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1

EAST AFRICA EAST AFRICA  

E-print Network

EAST AFRICA #12;EAST AFRICA Investment Invested in research and student programs in East Africa $2.7+million SHARCNET Access granted to all partner universities in East Africa CIDA UPCD project, Rebuilding of The Africa Institute at The University of Western Ontario (2011) #12;EAST AFRICA Recruitment and Building

Denham, Graham

2

The seismicity in Kenya (East Africa) for the period 1906-2010: A review  

NASA Astrophysics Data System (ADS)

Kenya has had a seismic station since 1963 as part of the World Wide Standardized Seismograph Network (WWSSN). In 1990, the University of Nairobi in collaboration with GeoForschungsZentrum (GFZ) started to build up a local seismological network, the Kenya National Seismic Network (KNSN), which operated for about ten years between 1993-2002. This, however, experienced a myriad of problems ranging from equipment breakdown, vandalism and lack of spares. Kenya is seismically active since the Kenya rift valley traverses through the country from north to south bisecting the country into eastern and western regions. In the central part, the Kenya rift branches to form the NW-SE trending Kavirondo (Nyanza) rift. The Kenya rift valley and the Kavirondo (Nyanza) rift are the most seismically active where earthquakes of local magnitude (Ml) in the order of ?2.0-5.0 occur. Furthermore, historical records show that earthquakes of magnitudes of the order of Ml ? 6.0 have occurred in Kenya. Such large magnitude earthquakes include the January 6, 1928 Subukia earthquake (Ml 7.1) and an aftershock (Ml 6.2) four days later, as well as the 1913 Turkana region earthquake (Ml 6.2). Since early 1970's, numerous seismic investigations have been undertaken in Kenya in order to understand the formation and structure of the Kenyan part of the East African rift valley. Earthquake data from these studies is, however, rather disorganized and individual datasets, including that acquired during the period 1993-2002, cannot furnish us with comprehensive information on the seismicity of Kenya for the past ?100 years. The purpose of this paper is, therefore, to review the seismicity in Kenya for the period 1906-2010 by utilizing data and results from different sources. The general seismicity of Kenya has been evaluated using historical data, data recorded by local seismic networks, the United States Geological Survey catalogue as well as earthquake data from the numerous seismic investigations by different individuals and research groups. On the basis of earthquake data from these sources, the entire N-S trending Kenya rift valley and the NW-SE trending Nyanza (Kavirondo) rift are characterized by a high rate of seismicity, and the USGS network has been effective in detecting local M > 3.0 earthquakes. A peculiar trend is exhibited by earthquakes of Ml ? 5.1 in that these occur along the N-S and NW-SE trending Kenya rift valley and the Kavirondo (Nyanza) rift zone respectively. Earthquake data from the various sources for the period 1906-2010 is complete for Ml ? 4.4 earthquakes with a b-value of 0.79 which is characteristic of tectonic active regions like rifts. There is need to revive and extend the KNSN for a greater coverage and effective seismic monitoring in Kenya.

Mulwa, J. K.; Kimata, F.; Suzuki, S.; Kuria, Z. N.

2014-01-01

3

Yellow fever virus susceptibility of two mosquito vectors from Kenya, East Africa.  

PubMed

Yellow fever is an unpredictable disease of increasing epidemic threat in East Africa. Aedes (Stegomyia) aegypti has never been implicated as a vector in this region and recent outbreaks have involved a newly emerging virus genotype (East African). To better understand the increasing epidemic risk of yellow fever in East Africa, this study is the first to investigate the vector competence for an emerging East African virus genotype in Kenyan A. aegypti sensu latu (s.l) and A. (Stegomyia) simpsoni s.l. mosquito species. Using first filial generation mosquitoes and a low passage yellow fever virus, this study demonstrated that although A. aegypti s.l. is a competent vector, A. simpsoni s.l. is likely a more efficient vector. PMID:22521217

Ellis, Brett R; Sang, Rosemary C; Horne, Kate McElroy; Higgs, Stephen; Wesson, Dawn M

2012-06-01

4

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

5

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

6

Components of rainy seasons variability in Equatorial East Africa : onset, cessation, rainfall frequency and intensity  

E-print Network

1 Components of rainy seasons variability in Equatorial East Africa : onset, cessation, rainfall rainfall variables is analysed over Equatorial East Africa (Kenya and northeastern Tanzania). At station

Boyer, Edmond

7

Distribution of Glycerol Diakyl Glycerol Tetraethers in Surface Soil and Crater Lake Sediments from Mount Kenya, East Africa  

NASA Astrophysics Data System (ADS)

Glycerol diakyl glycerol tetraethers (GDGTs), a palaeoclimate proxy based on the relative abundance of lipids produced by archaea and bacteria, is gaining wide acceptance for the determination of past temperature and pH conditions. This study looks at the spatial distribution and abundance of GDGTs in soil and sediment samples along an altitudinal transect from 3 crater lakes of Mt. Kenya (Lake Nkunga, Sacred Lake and Lake Rutundu) ranging in elevation from 1700m - 3080m above sea level. GDGTs were extracted with solvents and then analysed using high performance liquid chromatography/atmospheric pressure chemical ionization-mass spectrometry (HPLC/APCI-MS). Mean annual air temperature and pH were estimated based on the relative abundance of the different branched GDGTs, i.e. on the MBT (Methylation index of Branched Tetraethers) and CBT (Cyclization ratio of Branched Tetraethers) indices. Substantial amount of GDGTs were detected in both soil and sediment samples. In addition, branched GDGT distribution was observed to vary with altitude. These results highlight the importance of quantifying the branched GDGTs to understand the environmental parameters controlling the distribution of these lipids. The MBT/CBT proxy is a promising tool to infer palaeotemperatures and characterize the climate events of the past millennia in equatorial east Africa.

Omuombo, C.; Huguet, A.; Olago, D.; Williamson, D.

2013-12-01

8

Mercury in fish from three rift valley lakes (Turkana, Naivasha and Baringo), Kenya, East Africa  

Microsoft Academic Search

Total mercury (THg) concentrations were measured for various fish species from Lakes Turkana, Naivasha and Baringo in the rift valley of Kenya. The highest THg concentration (636 ng g?1 wet weight) was measured for a piscivorous tigerfish Hydrocynus forskahlii from Lake Turkana. THg concentrations for the Perciformes species, the Nile perch Lates niloticus from Lake Turkana and the largemouth bass

L. M. Campbell; O. Osano; R. E Hecky; D. G Dixon

2003-01-01

9

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

10

Influenza in East Africa  

PubMed Central

Very little information is available concerning the frequency of influenza in East Africa. Following recent outbreaks of influenza in Uganda, that were due to the A2/Hong Kong/68 virus, it was considered useful to obtain information relating to the prevalence of infection due to this virus and to the current strain of influenza B virus, not only in Uganda but also in the neighbouring territories of Kenya and Tanzania. The results of serological testing of sera showed that widespread outbreaks of influenza A2/Hong Kong/68 infection had occurred recently in all three territories, while there was evidence of sporadic infection in all territories by the current influenza B strain. Despite the favourable climate of East Africa, it is evident that widespread outbreaks of influenza can occur, and these may arise during the period of the year when influenza is rare in countries with temperate climates. Influenza can easily spread to other countries via air travellers to and from East Africa. PMID:5312523

Montefiore, D.; Drozdov, S. G.; Kafuko, G. W.; Fayinka, O. A.; Soneji, A.

1970-01-01

11

Mercury in fish from three rift valley lakes (Turkana, Naivasha and Baringo), Kenya, East Africa.  

PubMed

Total mercury (THg) concentrations were measured for various fish species from Lakes Turkana, Naivasha and Baringo in the rift valley of Kenya. The highest THg concentration (636 ng g(-1) wet weight) was measured for a piscivorous tigerfish Hydrocynus forskahlii from Lake Turkana. THg concentrations for the Perciformes species, the Nile perch Lates niloticus from Lake Turkana and the largemouth bass Micropterus salmoides from Lake Naivasha ranged between 4 and 95 ng g(-1). The tilapiine species in all lakes, including the Nile tilapia Oreochromis niloticus, had consistently low THg concentrations ranging between 2 and 25 ng g(-1). In Lake Naivasha, the crayfish species, Procambrus clarkii, had THg concentrations similar to those for the tilapiine species from the same lake, which is consistent with their shared detritivore diet. THg concentrations in all fish species were usually consistent with their known trophic position, with highest concentrations in piscivores and declining in omnivores, insectivores and detritivores. One exception is the detritivore Labeo cylindricus from Lake Baringo, which had surprisingly elevated THg concentrations (mean=75 ng g(-1)), which was similar to those for the top trophic species (Clarias and Protopterus) in the same lake. Except for two Hydrocynus forskahlii individuals from Lake Turkana, which had THg concentrations near or above the international marketing limit of 500 ng g(-1), THg concentrations in the fish were generally below those of World Health Organization's recommended limit of 200 ng g(-1) for at-risk groups. PMID:12810322

Campbell, L M; Osano, O; Hecky, R E; Dixon, D G

2003-01-01

12

FAO Forestry Department Wood Energy WISDOM East Africa  

E-print Network

FAO ­ Forestry Department ­ Wood Energy WISDOM ­ East Africa Woodfuel Integrated Supply http://www.fao.org/docrep/009/j8227e/j8227e00.htm #12;6 #12;East Africa WISDOM iii Foreword case involves ten countries of east and central Africa: Rwanda, Kenya, Egypt, Burundi, DR Congo

13

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

14

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

15

Kenya.  

PubMed

Attention in this discussion of Kenya is directed to the following: geography; people; history; government; political conditions; the economy; defense; and relations between Kenya and the US. In 1987, the population was estimated at 21.6 million with an estimated annual growth rate of 4.1%. Traditional herders, Arab Muslims, and cosmopolitan residents of Nairobi all contribute to the culture of Kenya. The standard of living in major cities is among the highest in sub-Saharan Africa. Fossils located in east Africa suggest that protohumans roamed the area more than 20 million years ago. Recent anthropological finds near Kenya's Lake Turkana indicate that the "Homo" genus of humans lived in the area 2.6 million years ago. Kenya's colonial history dates from the Berlin conference of 1885. In 1895, the British government established the East African Protectorate and, soon after, opened the fertile highlands to white settlers. The settlers were allowed a voice in government before it officially was made a British colony in 1920, but Africans were not permitted any direct political participation until 1944. Kenya became independent on December 12, 1963, and in 1964 assumed the status of a republic within the Commonwealth. The president is elected by the National Assembly to serve a 5-year term, but if the president dissolves the assembly, a new presidential election must be held. Since independence, Kenya has maintained remarkable stability during many changes within the democratic system. Kenya's major political challenge is to reinvigorate its economy, which has suffered from a combination of problems such as government deficit spending, a chronic shortage of foreign exchange, and the rising cost of oil imports. Economic growth has declined since 1973, and real gross domestic product (GDP) has grown only by about 2.75% for the 1980-86 period. One of Kenya's basic problems is its population growth rate. With less than 20% of the land classified as potentially arable and much of that already densely populated, food crop production faces serious constraints. The US and Kenya enjoy cordial relations. The main purpose of US bilateral assistance to Kenya is to promote broad-based economic development as the basis for continued progress in political, social, and related areas of national life. US aid strategy is structured around 3 major objectives: reduced population growth; increased rural production, employment, and income; and efficient, basic social services. PMID:12177968

1988-01-01

16

Faculty Position in East Africa  

E-print Network

Faculty Position in East Africa Carnegie Mellon University is embarking on an exciting opportunity to transform graduate education in East Africa by introducing new models of education, research and development.Striving to become the technology hub for East Africa,Rwanda is investing heavily in infrastructure and capacity

McGaughey, Alan

17

LEast African Currency Board e la genesi dellattivit bancaria nellAfrica Orientale Britannica  

Microsoft Academic Search

THE CURRENCY BOARD AND THE RISE OF BANKING IN EAST AFRICA. The East Africa region consists today of three independent countries, Kenya, Tanzania (formerly Tanganyika) and Uganda, which, from the early 1920s to the achievement of independence, formed an administrative unit under British rule: the British East Africa. The paper presents an historical synthesis of the basic problems and developments

Arnaldo MAURI

2007-01-01

18

Phylodynamics of HIV-1 Subtype C Epidemic in East Africa  

PubMed Central

The HIV-1 subtype C accounts for an important fraction of HIV infections in east Africa, but little is known about the genetic characteristics and evolutionary history of this epidemic. Here we reconstruct the origin and spatiotemporal dynamics of the major HIV-1 subtype C clades circulating in east Africa. A large number (n?=?1,981) of subtype C pol sequences were retrieved from public databases to explore relationships between strains from the east, southern and central African regions. Maximum-likelihood phylogenetic analysis of those sequences revealed that most (>70%) strains from east Africa segregated in a single regional-specific monophyletic group, here called CEA. A second major Ethiopian subtype C lineage and a large collection of minor Kenyan and Tanzanian subtype C clades of southern African origin were also detected. A Bayesian coalescent-based method was then used to reconstruct evolutionary parameters and migration pathways of the CEA African lineage. This analysis indicates that the CEA clade most probably originated in Burundi around the early 1960s, and later spread to Ethiopia, Kenya, Tanzania and Uganda, giving rise to major country-specific monophyletic sub-clusters between the early 1970s and early 1980s. The results presented here demonstrate that a substantial proportion of subtype C infections in east Africa resulted from dissemination of a single HIV local variant, probably originated in Burundi during the 1960s. Burundi was the most important hub of dissemination of that subtype C clade in east Africa, fueling the origin of new local epidemics in Ethiopia, Kenya, Tanzania and Uganda. Subtype C lineages of southern African origin have also been introduced in east Africa, but seem to have had a much more restricted spread. PMID:22848653

Delatorre, Edson Oliveira; Bello, Gonzalo

2012-01-01

19

Developing a systemic approach to teacher education in sub-Saharan Africa: emerging lessons from Kenya, Tanzania and Uganda  

Microsoft Academic Search

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,

Frank Hardman; Jim Ackers; Niki Abrishamian; Margo OSullivan

2011-01-01

20

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

21

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

22

Neolithic Pottery Traditions from the Islands, the Coast and the Interior of East Africa  

Microsoft Academic Search

Scholars have attributed the spread of agriculture and pottery technology to the larger part of eastern and southern Africa to Bantu speakers. However, the spread of similar aspects to the Kenya and Tanzania Rift Valley as far south as Eyasi Basin and as far east as Mount Kilimanjaro has been attributed to Cushitic speakers. Whereas the spread of these innovations

Felix A. Chami; Amandus Kwekason

2003-01-01

23

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

24

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

25

A Scientific note on Varroa mites found in East Africa; Threat or Opportunity  

Technology Transfer Automated Retrieval System (TEKTRAN)

Varroa mites have devastated Apis mellifera L. honeybee populations wherever they co-occur around the world, yet in East Africa these mites may have finally met their match. Varroa destructor Anderson and Truman (Acari:Varroidae) was found in Kenya and Tanzania for the first time in early 2009, but...

26

A Biocultural Framework for Examining Maternal Cravings and Aversions among Pastoral Women in East Africa  

Microsoft Academic Search

Food preferences during pregnancy result from a complex set of biocultural interactions with important implications for maternal and child health. This article explores the social context of maternal food choice in marginal environments of East Africa. Biocultural data collected among Turkana and Datoga women living in Kenya and Tanzania indicate there is a significant social context to food choice that

Alyson G. Young; Ivy L. Pike

2012-01-01

27

Integrating diverse methods to understand climateland interactions in East Africa  

E-print Network

Integrating diverse methods to understand climate­land interactions in East Africa Jennifer M-disciplinary scientists examining climate­land dynamics at multiple scales in East Africa. East Africa is a region

28

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

29

New hominids from East Turkana, Kenya.  

PubMed

Thirty-five new fossil hominid specimens are described. They were recovered from the Plio-Pleistocene sediments to the east of Lake Turkana (formerly Lake Rudolf). They include cranial and mandibular parts, teeth, and postcranial bones of upper and lower limbs. Parts of a single skeleton are also described. All of the specimens are described in anatomical detail and selected measurements are given. Some of the specimens are illustrated. It is proposed that they should be attributed to the family Hominidae, with genus and species undetermined until detailed comparative studies have been undertaken. PMID:826171

Day, M H; Leakey, R E; Walker, A C; Wood, B A

1976-11-01

30

The alternative of Chinese aid in Africa : impacts of China's development strategy through Chinese aid, finance, and firms in Kenya  

E-print Network

This thesis examines the differences of Chinese and Western aid implementation and its effects in Africa though the case study of Chinese aid and finance for road development in Kenya. Today, Kenya receives tangible benefits ...

Mullin, Deborah Wei

2009-01-01

31

Azania XLII 2007 East Africa, the Comoros Islands and  

E-print Network

Azania XLII 2007 East Africa, the Comoros Islands and Madagascar before the sixteenth century and China' (al-Bîrûnî, ca. 1030, trans. Ferrand 1907: 552) The historical developments of East Africa expansion and private enterprise. #12;16 East Africa, the Comoros Islands and Madagascar before

Paris-Sud XI, Université de

32

View of east Africa ravaged by drought  

NASA Technical Reports Server (NTRS)

A near vertical view of a portion of east Africa revaged by drought for the past five years is seen in this Skylab 3 Earth Resources Experiments Package S190-B (five-inch earth terrain camera) photograph taken from the Skylab space station in Earth orbit. The semi-desert scene is in southwestern Niger.

1973-01-01

33

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. PMID:10491248

Wang, Peiyi; Adair, Richard

1999-01-01

34

Genomic adaptation of admixed dairy cattle in East Africa  

PubMed Central

Dairy cattle in East Africa imported from the U.S. and Europe have been adapted to new environments. In small local farms, cattle have generally been maintained by crossbreeding that could increase survivability under a severe environment. Eventually, genomic ancestry of a specific breed will be nearly fixed in genomic regions of local breeds or crossbreds when it is advantageous for survival or production in harsh environments. To examine this situation, 25 Friesians and 162 local cattle produced by crossbreeding of dairy breeds in Kenya were sampled and genotyped using 50K SNPs. Using principal component analysis (PCA), the admixed local cattle were found to consist of several imported breeds, including Guernsey, Norwegian Red, and Holstein. To infer the influence of parental breeds on genomic regions, local ancestry mapping was performed based on the similarity of haplotypes. As a consequence, it appears that no genomic region has been under the complete influence of a specific parental breed. Nonetheless, the ancestry of Holstein-Friesians was substantial in most genomic regions (>80%). Furthermore, we examined the frequency of the most common haplotypes from parental breeds that have changed substantially in Kenyan crossbreds during admixture. The frequency of these haplotypes from parental breeds, which were likely to be selected in temperate regions, has deviated considerably from expected frequency in 11 genomic regions. Additionally, extended haplotype homozygosity (EHH) based methods were applied to identify the regions responding to recent selection in crossbreds, called candidate regions, resulting in seven regions that appeared to be affected by Holstein-Friesians. However, some signatures of selection were less dependent on Holsteins-Friesians, suggesting evidence of adaptation in East Africa. The analysis of local ancestry is a useful approach to understand the detailed genomic structure and may reveal regions of the genome required for specialized adaptation when combined with methods for searching for the recent changes of haplotype frequency in an admixed population.

Kim, Eui-Soo; Rothschild, Max F.

2014-01-01

35

Khat in East Africa: taking women into or out of sex work?  

PubMed

Women's drug use is often associated with sex work as a means of raising money for consumption. Similarly, in Kenya and Uganda, journalists, the general public and aid agencies associate female consumption of the stimulant drug, khat (Catha edulis), as pulling women into prostitution. In contrast to Yemen and Ethiopia, these views are expressed by people living in areas where there are no rituals or traditions of female khat consumption. This paper presents data from a study carried out in Kenya and Uganda in 2004 and 2005 that documents that the majority of women engaging in khat chewing are not sex workers. Frequently, however, women who retail khat are often assumed by men to be sexually immoral. The role of women in the retail and wholesale khat trade is examined. The stigma attached to selling khat is linked to the overall situation of independent women in East Africa and the place of commercial sex in urban life. PMID:18649237

Beckerleg, Susan

2008-07-01

36

An overview of the transboundary aquifers in East Africa  

NASA Astrophysics Data System (ADS)

A transboundary aquifer is a body of groundwater intersected by two or more countries with the potential threat of dispute over a shared groundwater resource. A large portion of the population in East Africa relies on surface water resources for day-to-day activities; in turn, this is dependent on episodic rainfall. Surface water in the region is vulnerable to pollution and potential climate change. Consequently, frequent conflict over the water use is a regular event in the region. This paper examines the transboundary aquifers and their significance for water supply in the six adjacent Intergovernmental Authority on Development (IGAD) countries (Ethiopia, Eritrea, Sudan, Kenya, Somalia and Djibouti). Analysis of available literature and short field visits to accessible areas were undertaken in order to examine the geology, hydrogeological dynamics, and water use. The geology of the transboundary aquifers is mainly represented by Precambrian basement, Mesozoic sedimentary rocks, Cenozoic volcanics and recent alluvial deposits. Taking into consideration the topographic setting and water circulation, the Ethiopian highlands are the major sources of recharge to the transboundary aquifers of the adjacent countries. The surface runoff drains through 11 major rivers into the neighbouring countries. The groundwater contained in the transboundary aquifers is yet to receive attention by the various countries, but the future trend is towards exploiting the resources to alleviate water shortages in the region. It is hoped that the systematic development of these groundwater resources would strengthen cooperation in this conflict-dominated region.

Abiye, Tamiru Alemayehu

2010-11-01

37

Pastoralists and hydatid disease: an ultrasound scanning prevalence survey in east Africa.  

PubMed

An attempt was made to estimate the prevalence of hydatid disease in nomadic pastoralists living in eastern Africa and to identify environmental, cultural and behavioural factors which may influence Echinococcus transmission. 18,565 nomadic pastoralists, from 12 different groups living in the vast, semi-desert regions of Kenya, Sudan, Ethiopia and Tanzania, were screened for hydatid cysts using a portable ultrasound scanner. High prevalences of hydatidosis were recorded among the north-western (5.6%) and north-eastern (2.1%) Turkana of north-west Kenya, the Toposa (3.2%) of southern Sudan, the Nyangatom (2.2%), Hamar (0.5%) and Boran (1.8%) of south-west Ethiopia and northern Kenya and the Maasai (1.0%) of Tanzania. Lower prevalences were recorded amongst the southern (0.3%) and lake dwelling (0.3%) Turkana and the Pokot (0.1%) of Kenya. The disease was not found amongst the Turkana, Samburu, Dassanetch, Gabbra, Somali or Rendille screened on the east side of Lake Turkana. The scanning surveys were well accepted by the people and provided evidence for the need to expand the present hydatid control programme in Turkana to cover the whole hyperendemic focus. Such a programme must contain an educational component for, although most groups recognized hydatid cysts, there was complete lack of knowledge concerning the parasite and its mode of transmission. PMID:2692230

Macpherson, C N; Spoerry, A; Zeyhle, E; Romig, T; Gorfe, M

1989-01-01

38

Recent outbreaks of rift valley Fever in East Africa and the middle East.  

PubMed

Rift Valley fever (RVF) is an important neglected, emerging, mosquito-borne disease with severe negative impact on human and animal health. Mosquitoes in the Aedes genus have been considered as the reservoir, as well as vectors, since their transovarially infected eggs withstand desiccation and larvae hatch when in contact with water. However, different mosquito species serve as epizootic/epidemic vectors of RVF, creating a complex epidemiologic pattern in East Africa. The recent RVF outbreaks in Somalia (2006-2007), Kenya (2006-2007), Tanzania (2007), and Sudan (2007-2008) showed extension to districts, which were not involved before. These outbreaks also demonstrated the changing epidemiology of the disease from being originally associated with livestock, to a seemingly highly virulent form infecting humans and causing considerably high-fatality rates. The amount of rainfall is considered to be the main factor initiating RVF outbreaks. The interaction between rainfall and local environment, i.e., type of soil, livestock, and human determine the space-time clustering of RVF outbreaks. Contact with animals or their products was the most dominant risk factor to transfer the infection to humans. Uncontrolled movement of livestock during an outbreak is responsible for introducing RVF to new areas. For example, the virus that caused the Saudi Arabia outbreak in 2000 was found to be the same strain that caused the 1997-98 outbreaks in East Africa. A strategy that involves active surveillance with effective case management and diagnosis for humans and identifying target areas for animal vaccination, restriction on animal movements outside the affected areas, identifying breeding sites, and targeted intensive mosquito control programs has been shown to succeed in limiting the effect of RVF outbreak and curb the spread of the disease from the onset. PMID:25340047

Himeidan, Yousif E; Kweka, Eliningaya J; Mahgoub, Mostafa M; El Rayah, El Amin; Ouma, Johnson O

2014-01-01

39

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

40

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)

1996-12-31

41

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

PubMed

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 provide evidence of morphological continuity between the two taxa. Here we describe two new cranial fossils from the Koobi Fora Formation, east of Lake Turkana in Kenya, that have bearing on the relationship between species of early Homo. A partial maxilla assigned to H. habilis reliably demonstrates that this species survived until later than previously recognized, making an anagenetic relationship with H. erectus unlikely. The discovery of a particularly small calvaria of H. erectus indicates that this taxon overlapped in size with H. habilis, and may have shown marked sexual dimorphism. The new fossils confirm the distinctiveness of H. habilis and H. erectus, independently of overall cranial size, and suggest that these two early taxa were living broadly sympatrically in the same lake basin for almost half a million years. PMID:17687323

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

2007-08-01

42

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

43

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

44

Analysis of the Junction of the East African Rift and the Cretaceous-Paleogene Rifts in Northern Kenya and Southern Ethiopia  

NASA Astrophysics Data System (ADS)

The East African rift (EAR) is a Tertiary-Miocene system that extends from the Middle East, through East Africa, to Mozambique in southern Africa. Much of the present information is from the Ethiopian and Kenyan parts of the rift. Several characteristics of the EAR such as rift-related volcanism, faulting and topographic relief being exposed make it attractive for studying continental rift processes. Structural complexities reflected in the geometries of grabens and half-grabens, the existence of transverse fault zones and accommodation zones, and the influence of pre-existing geologic structures have been documented. In particular, the EAR traverses the Anza graben and related structures near the Kenya/Ethiopian border. The Anza graben is one in a series of Cretaceous-Paleogene failed rifts that trend across Central Africa from Nigeria through Chad to Sudan and Kenya with an overall northwest-southeast trend. In spite of a number of recent studies, we do not understand the interaction of these two rift systems. In both Ethiopia and Kenya, the rift segments share some broad similarities in timing and are related in a geographic sense. For example, volcanism appears to have generally preceded or in some cases have been contemporaneous with major rift faulting. Although, these segments are distinct entities, each with its own tectonic and magmatic evolution, and they do connect in the region crossed by the Anza graben and related structures. In our present study, we are using a combination of recently collected seismic, gravity and remote sensing data to increase our understanding of these two segments of the EAR. We hope that by analysing the satellite data, the variety and differences in the volume of magmatic products extruded along in southern Ethiopia and northern Kenya will be identified. The geometry of structures (in particular, those causing the gravity axial high) will be modelled to study the impact of the older Anza graben structural trends with the younger EAR. For example there is significant crustal thinning in the Lake Turkana area of the northern Kenya segment of the EAR system. In regard to the recent EAGLE experiment in Ethiopia, we are ivestigating if the transition from relatively thick crust (~40 km) to thinned, rifted crust is as abrupt in Ethiopia as it is in Kenya.

Mariita, N. O.; Tadesse, K.; Keller, G. R.

2003-12-01

45

A Heated Debate: Evidence for Two Thermal Upwellings in East Africa  

NASA Astrophysics Data System (ADS)

East African Cenozoic magmatism records the thermal influence of one or more long-lived mantle plumes. We present primary magma compositions, mantle potential temperatures (Tp), and mantle melt fractions using PRIMELT2 in order to examine the geographic and historical distribution of upper mantle thermal anomalies in East Africa. Regional magmatism can be divided into an early flood basalt phase in Ethiopia/Yemen (~30 Ma), a longer-lived episode of basaltic magmatism in Kenya and Southern Ethiopia (~45 to 23 Ma), and a more recent phase (~23 Ma to Present) that is coincidental with the development of the East African Rift (EAR). We have carefully selected a total of 54 samples from these time periods, excluding erroneous results derived from lavas with evidence of clinopyroxene fractionation or volatile rich and pyroxenitic sources. Our results show that elevated Tp in the Ethiopian/Yemen flood basalt province (Tp max =1520C) and in the early Kenya/S. Ethiopia magmatism (Tp max = 1510C) are virtually identical. Our results indicate that the existing geochemical division between high and low Ti Ethiopia/Yemen flood basalts has a thermal basis: low-Ti lavas are hotter than the high-Ti lavas. Magmatism in the region subsequent to 23 Ma exhibits only minor cooling (Tp max = 1490C), though more substantial cooling is observed in Turkana, Kenya (60C) and Yemen (80C). Rift lavas from Ethiopia exhibit a clear decrease in Tp away from Afar southwestward along the EAR before progressively rising again in Southern Ethiopia towards Turkana. South of Turkana, elevated Tp is observed in the western and eastern branches of the EAR surrounding the Tanzania Craton. The modern spatial distribution of Tp in EAR magmatism indicate two distinct heat sources, one in Afar and another under the Tanzania craton. We suggest that hot mantle plume material from Afar and Turkana (which may or may not merge at depth) is channeled beneath the thinned rift lithosphere and provides a significant thermal input to EAR magmatism resulting in elevated Tp, even in magmas clearly derived from the lithosphere. Our results add to the debate generated by numerous global-scale tomographic inversions that presently do not show consensus as to the number and location of low-velocity upwellings beneath East Africa.

Rooney, T.; Herzberg, C.; Bastow, I.

2008-12-01

46

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. PMID:15941419

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

2011-01-01

47

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

48

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

NASA Astrophysics Data System (ADS)

Soil erosion threatens the food security of 2.6 billion people worldwide. The situation is particularly dire in East and Sub-Saharan Africa where per capita food production has declined over the past 45 years. Erosion and the resultant loss of fertile soil is a key socio-economic and ecological problem in Kenya, affecting all sectors of its economy and damaging marine and terrestrial ecosystems. The temporal pattern of soil erosion is almost unknown and currently only sparse and rather anecdotal information exists. To aid in filling this gap of knowledge, we present a 300-year long Barium record from two Kenyan coral colonies (Porites sp., 315'S, 409' E; Malindi Marine National Park) that documents a dynamic history of soil erosion in the Sabaki river drainage basin. To reconstruct Sabaki River sediment flux to the Malindi coral reef Ba/Ca ratios were measured in the skeleton of two Porites colonies (Mal 96-1 and Mal 95-3). Well-developed annual bands allow us to develop annually precise chronologies. Ba/Ca ratios were measured in core Mal 96-1 at continuous 40 ?m intervals (~400 to 500 samples yr-1) using laser-ablation inductively coupled plasma mass spectrometry (LA- ICP-MS). To test for reproducibility and accuracy of the Mal 96-1 Ba/Ca profile, coral core Mal 95-3 was analyzed at lower resolution (1 to 12 samples yr-1) using discrete micro-drill sampling and isotope dilution ICP-MS. The close similarity between both coral Ba/Ca profiles, in absolute values as well as general pattern, underscores the accuracy of the LA-ICP-MS technique and adds confidence to our interpretation of the 300 year long Mal 96-1 Ba/Ca profile. The Ba/Ca coral proxy record shows that while the sediment flux from the Sabaki River is nearly constant between 1700 and 1900, a continuous rise in sediment flux is observed since 1900, reflecting steadily increasing demographic pressure on land use. The peak in suspended sediment load and hence soil erosion recorded at the Malindi reef occurred between 1974 and 1980 where there is a five to tenfold increase relative to natural levels. This is attributed to the combined effects of dramatically increasing population, unregulated land use, deforestation and severe droughts in the early 1970s. It is concluded that despite laudable attempts to instigate soil conservation measures, it is unlikely that in Kenya there will be a sustainable reduction in soil erosion without a significant improvement in socio-economic conditions.

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

2006-12-01

49

Chronology of Quaternary glaciations in East Africa Timothy M. Shanahan *, Marek Zreda  

E-print Network

Chronology of Quaternary glaciations in East Africa Timothy M. Shanahan *, Marek Zreda Department 31 January 2000 Abstract A new glacial chronology for equatorial East Africa is developed using; East Africa; chronology 1. Introduction Tropical East Africa is one of three places on the equator

Zreda, Marek

50

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

51

Mshindi Kablanketi Dry Bean for East Africa  

Technology Transfer Automated Retrieval System (TEKTRAN)

Mshindi was derived from the single cross Rojo x Kablanketi made in Dec-Jan 1992-93. Mshindi was previously tested under the experimental number EG 21. Mshindi is Swahili for Winner. Mshindi out-yielded the check Kenya in 10 of 12 trials and had an overall yield advantage of 117%. Mshindi ha...

52

Omo River Delta, Lake Turkana, Ethiopia/Kenya border, Africa  

NASA Technical Reports Server (NTRS)

As a result of land clearing operations in the local area, the Omo River Delta (4.5N, 36.0E) at the north end of Lake Turkana, on the Ethiopia/Kenya border has become enlarged through topsoil erosion. The delta measured 800 sq. km. in 1981 doubled to 1,600 sq. km. by 1988 and was up to 1,800 sq. km. in 1991. This is the same area where the Leaky Anthropological Team discovered the earliest remains of human ancestors.

1991-01-01

53

Multiproxy Evidence for a Positive Hydrological Budget during the Little Ice Age in the East African Rift, Kenya  

NASA Astrophysics Data System (ADS)

Hominin evolution took place in Africa during the Plio-Pleistocene and climate change is thought to be a factor, with Africa experiencing a general cooling and increasing aridification over the last several million years. Today, the climate of the East African Rift Valley of Kenya is characterized as semi-arid with evapotranspiration four times precipitation. Water resources are a valuable commodity for the many millions of inhabitants of the Valley. The short instrumental record shows precipitation fluctuates at sub-decadal timeframes as a result of the ENSO cycle; while during prehistory variations in monsoonal precipitation occurred on Milankovitch timescales (i.e. African Humid Period). Both timescales exhibit significant impacts on the distribution of surface water. However, little is known regarding precipitation variability over sub-millennial timescales. Emerging paleoclimate data indicates that the near surface presence of water has also varied over century length timescales. We present paleoclimate data from multiple sites along a north-south 600 km transect of the Gregory Rift Valley (Kenya) that indicate the region experienced wetter conditions during the Little Ice Age (A.D. 1400-1850). Our reconstructions of landscape and climate during this time frame rely upon a multiproxy and interdisciplinary approach. We discuss data from a variety of environmental settings (e.g. lakes, wetlands, and springs) that indicate an overall increase in hydrologic balance. Evidence is derived from biologic microfossils such as pollen, diatom and testate amoebae assemblages as well as inorganic components of the sedimentary record and geomorphic changes. The data differs significantly from studies undertaken to the west in Uganda and the Congo, where negative hydrologic balances occurred during the Little Ice Age. While the atmospheric dynamics causing this disparity are not yet recognized, interactions between the Intertropical Convergence Zone and the Congo Air Boundary are a likely causal agent.

Goman, M.; Ashley, G. M.; Hover, V. C.; Owen, R.

2011-12-01

54

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. PMID:23611649

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

2013-01-01

55

A hominine hip bone, KNM-ER 3228, from East Lake Turkana, Kenya.  

PubMed

A male hominine partial hip bone, KNM -ER 3228, from East Lake Turkana , Kenya is described. In most of its features this specimen resembles modern human male hip bones. This is especially true for functional features related to weight transfer from the trunk to the pelvis and within the pelvis, and to the effective action of musculature arising from the pelvis during the performance of the modern human type of bipedalism . KNM -ER 3228 is very similar to the Olduvai Hominid 28 and the Arago XLIV hip bones, both attributed to Homo erectus . PMID:6428239

Rose, M D

1984-04-01

56

Pluralistic Modelling Approaches to Simulating Climate-Land Change Interactions in East Africa  

E-print Network

Pluralistic Modelling Approaches to Simulating Climate- Land Change Interactions in East Africa@purdue.edu Keywords: Land use, climate change, expert systems, role playing games, qualitative models, East Africa to understand how climate change impacts changes in land use in East Africa. A role playing game model has been

Illinois at Chicago, University of

57

An Agent-Based Model of Conflict in East Africa And the Effect of Watering Holes  

E-print Network

An Agent-Based Model of Conflict in East Africa And the Effect of Watering Holes William G. Kennedy conflict between herdsmen in east Africa using the MASON agent-based simulation environment is presented group. 1. Introduction The Mandera Triangle of East Africa is a complex environmental and human social

George Mason University

58

Wet periods along the East Africa Coast and the extreme wet spell event of October 1997  

E-print Network

1 Wet periods along the East Africa Coast and the extreme wet spell event of October 1997 R. E Meteorological Society 2, 1 (2008) 67-83" #12;2 Abstract Extreme wet spells affect the East Africa Coast (EAC. Introduction The East Africa Coast (EAC, fig.1) is regularly affected by heavy rainfall events. These events

Boyer, Edmond

59

Thermal plume models and melt generation in East Africa: A dynamic modeling approach  

E-print Network

= Thermal plume models and melt generation in East Africa: A dynamic modeling approach Shu The hypothesis that thermal plumes contribute to the Cenozoic magmatism in East Africa is now widely accepted for the melt generation in East Africa. We investigate how the plume(s), the Tanzania craton, and the African

van Keken, Peter

60

Recent glacial recession in the Rwenzori Mountains of East Africa due to rising air temperature  

E-print Network

Recent glacial recession in the Rwenzori Mountains of East Africa due to rising air temperature recent decline in the areal extent of glaciers in the Rwenzori Mountains of East Africa from 2.01 ± 0. Muwanga, and B. Nakileza (2006), Recent glacial recession in the Rwenzori Mountains of East Africa due

Jones, Peter JS

61

Use of vegetation properties from EOS observations for land-climate modeling in East Africa  

E-print Network

Use of vegetation properties from EOS observations for land-climate modeling in East Africa Jianjun East Africa. In this study, we used the NASA's Earth Observing System (EOS) products to improve greatly improved the spatial and temporal dynamics of vegetation in East Africa. Three experiments were

62

Pluralistic Modelling Approaches to Simulating Climate-Land Change Interactions in East Africa  

E-print Network

1 Pluralistic Modelling Approaches to Simulating Climate- Land Change Interactions in East Africa@purdue.edu Keywords: Land use, climate change, expert systems, role playing games, qualitative models, East Africa to understand how climate change impacts changes in land use in East Africa. A role playing game model has been

63

Aspects of Education in the Middle East and North Africa  

ERIC Educational Resources Information Center

The chapters in this volume do not represent the whole of the Middle East and North Africa, as such a collection would have been too large for one volume. Rather, the selection here is intended to present different perspectives on a range of educational issues, relevant to a particular focus or country, or common to a number of countries in the

Brock, Colin, Ed.; Levers, Lila Zia

2007-01-01

64

Reducing the Burden of Cancer in East Africa  

Cancer.gov

The mission of CGH is to advance global cancer research, build expertise, and leverage resources across nations to reduce cancer deaths worldwide. To carry out that mission, we facilitate the sharing of knowledge and expertise. CGH's latest effort, the East Africa Cancer Control Leadership Forum, carried out this mission by helping African partners develop their own individual cancer control programs.

65

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

66

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

67

Holocene TEX86 temperature reconstructions from Lake Turkana, East Africa  

Microsoft Academic Search

We present new high resolution Holocene lake surface temperature records from Lake Turkana, East Africa. These two TEX86 reconstructions, from the northern and southern basins of the lake, capture ~90 year resolution of climate patterns seen in this closed-basin system, as well as the thermal water dynamics between the two basins. The modern lake experiences surface temperatures in the northern

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

2009-01-01

68

A solar box cooker for mass production in East Africa  

SciTech Connect

A solar box cooker produced in Tanzania, East Africa with indigenous materials is described. When compared to a commercially produced glass and cardboard one, it was found to perform as well. Heat transfer through each major component of the cooker is presented. The smallest losses were through the walls of the box. The greatest losses were observed in the cover system.

Funk, P.A.; Wilcke, W.F. [Univ. of Minnesota, St. Paul, MN (United States). Dept. of Agricultural Engineering

1992-12-31

69

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

70

The Galla or Oroma of East Africa.  

PubMed

This brief anthropological study describes the Galla, or Oromo meaning "free men," who constitute one of the largest racial groups in Ethiopia and a small minority in Kenya. The people are characterized as warlike, and their women wield great influence over their husbands and enjoy a large degree of freedom of movement, especially for a Moslem community. The homes, clothing, food, history, tribal organization, law, religion, medicine, marriage customs, funeral customs, and social welfare all receive attention. Marriage is entered into for rearing children rather than romantic or sentimental reasons. Premarital intercourse, not leading to marriage, is common; but this custom is revoked upon marriage, where faithfulness is demanded. Until recently, 1st born girls were left to die of exposure, resulting in a relative scarcity of women and necessitating early betrothels. Marriage is by purchase, being arranged by the bride's family with the groom's assent. Medicine relies on witchdoctors and medicinemen who are familiar with indigenous plants and their uses. These medical practitioners are granted high esteem within the community. An extended family, headed by the grandfather until his death, ensures social welfare for all members of the community. PMID:12259237

Jaenen, C

1956-01-01

71

Climate Change Impacts on East Africa  

Microsoft Academic Search

\\u000a Africa contains about one-fifth of all known species of plants, mammals, and birds, as well as one-sixth of amphibians and\\u000a reptiles. These species make up some of the worlds most diverse and biologically important ecosystems, such as savannahs,\\u000a tropical forests, coral reef marines and freshwater habitats, wetlands, and montane ecosystems. These globally important ecosystems\\u000a provide the economic foundation that many

Muawya Ahmed Hussein

72

The development of the East African Rift system in north-central Kenya  

NASA Astrophysics Data System (ADS)

Between 1980 and 1986 geological surveying to produce maps on a scale of 1:250,000 was completed over an area of over 100,000 km 2 in north-central Kenya, bounded by the Equator, the Ethiopian border and longitudes 36 and 38 E. The Gregory Rift, much of which has the structure of an asymmetric half-graben, is the most prominent component of the Cenozoic multiple rift system which extends up to 200 km to the east and for about 100 km to the west, forming the Kenya dome. On the eastern shoulder and fringes two en echelon arrays of late Tertiary to Quaternary multicentre shields can be recognized: to the south is the Aberdares-Mount Kenya-Nyambeni Range chain and, to the north the clusters of Mount Kulal, Asie, Huri Hills and Marsabit, with plateau lavas and fissure vents south of Marsabit in the Laisamis area. The Gregory Rift terminates at the southern end of Lake Turkana. Further north the rift system splays: the arcuate Kinu Sogo fault zone forms an offset link with the central Ethiopian Rift system. In the rifts of north-central Kenya volcanism, sedimentation and extensional tectonics commenced and have been continuous since the late Oligocene. Throughout this period the Elgeyo Fault acted as a major bounding fault. A comparative study of the northern and eastern fringes of the Kenya dome with the axial graben reinforces the impression of regional E-W asymmetry. Deviations from the essential N-trend of the Gregory Rift reflect structural weaknesses in the underlying Proterozoic basement, the Mozambique Orogenic Belt: thus south of Lake Baringo the swing to the southeast parallels the axes of the ca. 620 Ma phase folds. Secondary faults associated with this flexure have created a "shark tooth" array, an expression of en echelon offsets of the eastern margin of the Gregory Rift in a transtensional stress regime: hinge zones where major faults intersect on the eastern shoulder feature intense box faulting and ramp structures which have counterparts in the rift system in southern Ethiopia. The NE- and ENE-trending fissures of the eastern fringes of the Kenya dome, notably in the Meru-Nyambeni areaand in the Huri and Marsabit shields, parallel late orogenic structures dated at around 580-480 Ma. Alkaline trends characterize the petrochemistry of the Cenozoic volcanics: In the Gregory Rift, voluminous Miocene alkali basalts, associated with hawaiite/mugearite lavas, define a trend culminating in the Miocene flood phonolites of the eastern shoulderand in the trachyphonolites, trachytes and peralkaline rhyolites, with associated pyroclastics, in central volcanoes such as Korosi, Paka and Silali. Such trends may manifest in the products of a single volcanic centre, also regionally on a broadly cyclic basis. On the eastern flanks of the Kenya dome the flood phonolites are less evident, but the same alkaline trends dominate the lava sequences, supplemented by nephelinitic extrusives in parts of the Nyambeni Range and in the Laisamis area. Results from recent seismicity surveys in the Laisamis area indicate that crustal extension may be currently active on the eastern fringes of the Kenya dome, but manifest at greater depths than in the axial Gregory Rift-Lake Turkana zone: a correlation is suggested with the ultra-alkaline petrochemistry of some of the eastern multicentre shields.

Hackman, B. D.; Charsley, T. J.; Key, R. M.; Wilkinson, A. F.

1990-11-01

73

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

74

Regional initiatives in support of surveillance in East Africa: The East Africa Integrated Disease Surveillance Network (EAIDSNet) Experience.  

PubMed

The East African Integrated Disease Surveillance Network (EAIDSNet) was formed in response to a growing frequency of cross-border malaria outbreaks in the 1990s and a growing recognition that fragmented disease interventions, coupled with weak laboratory capacity, were making it difficult to respond in a timely manner to the outbreaks of malaria and other infectious diseases. The East Africa Community (EAC) partner states, with financial support from the Rockefeller Foundation, established EAIDSNet in 2000 to develop and strengthen the communication channels necessary for integrated cross-border disease surveillance and control efforts. The objective of this paper is to review the regional EAIDSNet initiative and highlight achievements and challenges in its implementation. Major accomplishments of EAIDSNet include influencing the establishment of a Department of Health within the EAC Secretariat to support a regional health agenda; successfully completing a regional field simulation exercise in pandemic influenza preparedness; and piloting a web-based portal for linking animal and human health disease surveillance. The strategic direction of EAIDSNet was shaped, in part, by lessons learned following a visit to the more established Mekong Basin Disease Surveillance (MBDS) regional network. Looking to the future, EAIDSNet is collaborating with the East, Central and Southern Africa Health Community (ECSA-HC), EAC partner states, and the World Health Organization to implement the World Bank-funded East Africa Public Health Laboratory Networking Project (EAPHLNP). The network has also begun lobbying East African countries for funding to support EAIDSNet activities. PMID:23362409

Ope, Maurice; Sonoiya, Stanley; Kariuki, James; Mboera, Leonard E G; Gandham, Ramana N V; Schneidman, Miriam; Kimura, Mwihaki

2013-01-01

75

A REAPPRAAISAL OF THE GEOLOGY, GEOCHEMISTRY, STRUCTURES AND TECTONICS OF THE MOZAMBIQUE BELT IN KENYA, EAST OF THE RIFT SYSTEM  

Microsoft Academic Search

The largest segment of the Neoproterozoic Mozambique belt in Kenya occurs east of the north-south oriented Rift system. Geological works carried out in the country during the last few decades have progressively revealed the complexity of the geology, structures and tectonics of the Mozambique belt in the region. Important high grade tectono-thermal events in the belt took place between about

C. M. Nyamai; E. M. Mathu; N. Opiyo-Akech; E. Wallbrecher

76

A Reappraisal of the Geology, Structures and Tectonics of the Mozambique Belt in Kenya East of the Rift System  

Microsoft Academic Search

The largest segment of the Neoproterozoic Mozambique orogenic belt in Kenya occurs east of the north-south oriented rift system. Geological investigations carried out in the country during the last few decades have revealed the complexity of the geology, structures and tectonics of the Mozambique Belt in the region. Important high-grade tectonothermal events in the belt took place between ca. 845

C. M. N yamai; E. M. Mathu; E. Wallbrecher; N. Opiyo-Akechl

77

Chemical ecology: studies from East Africa.  

PubMed

The International Centre of Insect Physiology and Ecology (ICIPE), in Nairobi, provides a laboratory at which a multinational group of scientists pursues interdisciplinary research. In collaboration with their colleagues in biology, ICIPE chemists have characterized the sex pheromones of the tick which serves as a vector of East Coast fever and have identified a termite queen-cell-building pheromone. The structure of many anthropod defensive chemicals have been determined; most interesting of these are the trinervitenes, structurally novel diterpenoids from nasute termites. Several highly active insect antifeedants were discovered using a simple bioassay to screen selected East African plants. These antifeedants may provide leads for the development of new insect-control techniques. PMID:17745589

Meinwald, J; Prestwich, G D; Nakanishi, K; Kubo, I

1978-03-17

78

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. PMID:22958352

2012-01-01

79

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

80

Aquaculture for increased fish production in East Africa ?  

E-print Network

Fish is produced for human consumption and other purposes through capture fisheries and aquaculture. Fish production from natural stocks has already reached its limits and is declining while aquaculture production is increasing. Aquaculture is making a significant contribution to fish production in several countries thus proving to be a potential alternative to supplement the declining capture fisheries. In East Africa the contribution of aquaculture to the total fish production is still insignificant although it has been practised in the region since the 1900s. The predominant aquaculture production system in East Africa at present is small scale earthen ponds characterised by low inputs and low yields. Important ingredients for the emergence of a commercial aquaculture industry are highlighted with emphasis on the need for a conducive and harmonised policy framework across the region. This paper advocates a focused plan of action for aquaculture development in the region and makes succinct recommendations for fast transformation of the industry.

J. Rutaisire; H. Charo-karisa; A. P. Shoko; B. Nyandat

81

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. PMID:24968313

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

2014-01-01

82

Newborn screening: Experiences in the Middle East and North Africa  

Microsoft Academic Search

SummaryThis review presents the current experiences with newborn screening in the Middle East and North Africa region. The population\\u000a in the region is about 400 million, with high birth rate and an estimated 10 million newborns per year. The majority of the\\u000a population is of the Islamic faith and mostly Arab. The population is characterized by a high consanguinity (2570%)

A. A. Saadallah; M. S. Rashed

2007-01-01

83

Spatial phylodynamics of HIV-1 epidemic emergence in east Africa  

PubMed Central

Design We sought to investigate the evolutionary and historical reasons for the different epidemiological patterns of HIV-1 in the early epidemic. In order to characterize the demographic history of HIV-1 subtypes A and D in east Africa, we examined molecular epidemiology, geographical and historical data. Methodology We employed high-resolution phylodynamics to investigate the introduction of HIV-1A and D into east Africa, the geographic trends of viral spread, and the demographic growth of each subtype. We also used geographic information system data to investigate human migration trends, population growth, and human mobility. Results HIV-1A and D were introduced into east Africa after 1950 and spread exponentially during the 1970s, concurrent with eastward expansion. Spatiotemporal data failed to explain the establishment and spread of HIV based on urban population growth and migration. The low prevalence of the virus in the Democratic Republic of Congo before and after the emergence of the pandemic was, however, consistent with regional accessibility data, highlighting the difficulty in travel between major population centers in central Africa. In contrast, the strong interconnectivity between population centers across the east African region since colonial times has likely fostered the rapid growth of the epidemic in this locale. Conclusion This study illustrates how phylodynamic analysis of pathogens informed by geospatial data can provide a more holistic and evidence-based interpretation of past epidemics. We advocate that this landscape phylodynamics approach has the potential to provide a framework both to understand epidemics' spread and to design optimal intervention strategies. PMID:19644346

Gray, Rebecca R.; Tatem, Andrew J.; Lamers, Susanna; Hou, Wei; Laeyendecker, Oliver; Serwadda, David; Sewankambo, Nelson; Gray, Ronald H.; Wawer, Maria; Quinn, Thomas C.; Goodenow, Maureen M.; Salemi, Marco

2009-01-01

84

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

85

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. PMID:22368447

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

2012-01-01

86

Climate and Land Use Change Processes in East Africa While some regions of East Africa are being preserved as natural areas, others, including the  

E-print Network

Climate and Land Use Change Processes in East Africa While some regions of East Africa are being of the project is to establish the mechanisms that determine how climate and land use (primarily in the human-mediated realm, but also land use change through natural processes) interact with each other and possibly

87

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

88

New Australopithecus boisei specimens from east and west Lake Turkana, Kenya.  

PubMed

New specimens of Plio-Pleistocene Australopithecus boisei are described from east and west Lake Turkana in Northern Kenya. These include a cranium and partial mandible from deposits close to 2.5 Myr and two partial crania and two mandibles from later horizons. The earlier fossils enable us to decipher, for the first time, some of the in situ evolution of this species within the Turkana Basin. The following are among the important changes in the cranium through time: 1) increase in size and change in shape of the braincase, 2) changes in the meningeal vessel pattern and possibly in the venous drainage pattern, 3) increased flexion of the cranial base and decreased prognathism, and 4) changes in the temporal bone to bring about a more vertical posterior face of the petrous pyramid and the development of a strong articular eminence. PMID:3136654

Leakey, R E; Walker, A

1988-05-01

89

Upper mantle Q and thermal structure beneath Tanzania, East Africa from teleseismic P wave spectra  

E-print Network

Upper mantle Q and thermal structure beneath Tanzania, East Africa from teleseismic P wave spectra. Introduction [2] East Africa is a geologically unique region with Cenozoic volcanism and a developing., A. A. Nyblade, and J. Ritsema (2004), Upper mantle Q and thermal structure beneath Tanzania, East

Ritsema, Jeroen

90

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

91

Landscape feedbacks, Climate Change, and Food Production Risk in East Africa  

NASA Astrophysics Data System (ADS)

Land Cover/ Land Use Change (LCLUC) and climate change due to elevated levels of greenhouse gases (GHG) both exert strong influence over agricultural production in developing countries. In addition, LCLUC is a first-order climate forcing capable of mitigating or exacerbating GHG effects on climate. LCLUC and GHG forcings that alter climate may then in turn influence agricultural systems, thereby creating a feedback to LCLUC. These human-land-climate interactions are complex- particularly in heterogeneous landscapes like East Africa- where subsistence farming and highly variable growing season conditions are excellent for investigating the nature and magnitude of these interactions. Here we present results of a sensitivity test exploring these feedbacks in Kenya, Tanzania, Uganda, Rwanda, and Burundi. First, we assess the impacts of "aggressive" agricultural expansion and generally warmer, wetter boundary conditions due to large increases in GHG for 2050-2059 using the Regional Atmospheric Modeling System (RAMS). These results are contrasted to simulations conducted for 2000- 2009 conditions. Second, we examine simulated changes in agricultural yield using the process-based crop model CERES-Maize; we use maize as a proxy for all East African agricultural productivity. These simulated yields are imported into the Land Transformation Model (LTM), which, informed by socioeconomic constraints, develops a new projection of land cover under the new yield conditions. Third, by comparing the original "aggressive" landscape with the new yield-feedback landscape, we show areas exhibiting sensitivity to LCLUC under elevated GHG conditions. Although this is a mere sensitivity test, we can identify areas prone to potential food production disturbances. These sensitive areas, while unlikely to see climate and landscape changes this dramatic, can serve as "canaries in the coal mine" for predicting larger changes in East African food production. Additionally, we discuss key challenges of propagating error in coupling these systems.

Moore, N.; Pijanowski, B.; Lofgren, B.; Alagarswamy, G.

2008-12-01

92

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

93

Omnibus Report: Europe, Middle East, Africa, East Asia and Latin America.  

PubMed

5 papers deal respectively with economic development in Europe, the Middle East, Africa, East Asia, and Latin America. In Europe, basic problems include increasing political and military weakness; the high costs of social democracy; problems of the welfare state; the trend toward low or no-growth population rates; declining fertility combined with increasing longevity; increasing demand for social services and health care; industrial decline; continuing decline in economic indices; integration of the Left in European politics; and a pervasive trend toward neoconservatism. The paper on the Middle East focuses on Iran, Saudi Arabia, and the recent Egypt-Israel Treaty, in terms of assessment of the present situation followed by a prognosis for the future. The paper on Africa discusses 4 crises of development: 1) the crisis of national identity; 2) the crisis of poverty; 3) the crisis of colonialism and neocolonialism; and 4) the crisis of popular control over government. The paper on east Asia discusses the "economic miracles" and whether or not they are replicable elsewhere in the Pacific and Asia. Finally, the paper on Latin America focuses on the fact that despite expansion of the urban middle class through economic development and modernization, little economic improvement has resulted. The challenge of the 1980s will be to see whether Latin America can put its economies back on track while managing to channel more of the economic benefits to the "have-nots" and to allow more open, participatory systems. PMID:12179856

Gallagher, C F; Nolte, R H; Liebenow, J G; Ravenholt, A; Handelman, H

1979-01-01

94

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

95

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

96

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

97

Chapter 5: Policies on Free Primary and Secondary Education in East Africa--Retrospect and Prospect  

ERIC Educational Resources Information Center

This article reviews the evolution of education policies in the East African region in a historical context. The focus is on the formulation of policies for access to primary and secondary education in Kenya, Uganda, and Tanzania since their independence in the 1960s. The three countries have common characteristics and historical backgrounds. For

Oketch, Moses; Rolleston, Caine

2007-01-01

98

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

99

Diarrhoea and effects of different water sources, sanitation and hygiene behaviour in East Africa  

Microsoft Academic Search

published studies on domestic water use and environmental health in East Africa, based on direct observations or other reliable research methods. The objective of this study was to carry out a repeat analysis of domestic water use and environmental health in East Africa based on DOW I. The study was conducted in the same sites as DOW I. Field assistants

James K. Tumwine; John Thompson; Munguti Katua-Katua; Mark Mujwajuzi; Nick Johnstone; Elizabeth Wood; Ina Porras

2002-01-01

100

Mantle plumes and associated ow beneath Arabia and East Africa Sung-Joon Chang , Suzan Van der Lee  

E-print Network

Mantle plumes and associated ow beneath Arabia and East Africa Sung-Joon Chang , Suzan Van der Lee Keywords: seismic tomography joint inversion mantle plume mantle ow Arabia East Africa We investigate-velocity structure beneath Arabia and East Africa. This image shows elongated vertical and horizontal low- velocity

van der Lee, Suzan

101

65 FR 30564 - International Trade Administration Business Development Trade Mission to Egypt, Kenya, and South...  

Federal Register 2010, 2011, 2012, 2013

...Mission to Egypt, Kenya, and South Africa AGENCY: International Trade Administration...Mission to Egypt, Kenya, and South Africa, October 1-7, 2000. [[Page...countries of Egypt, Kenya and South Africa. This Business Development...

2000-05-12

102

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

103

Quinine resistant falciparum malaria acquired in east Africa.  

PubMed

A 43 year old man with falciparum malaria acquired in East Africa was treated with quinine intravenously at a loading dose of 500 mg and subsequently 500 mg tid. Within 42 hours after initiation of treatment the parasitaemia increased from 2% to 16%. A RIII-resistance against quinine was suspected and therapy was switched to oral administration of halofantrine (500 mg at 6 hourly intervals) which led to complete recovery. Blood samples were cultured for malaria parasites 42 hours after start of therapy with quinine but before initiation of therapy with halofantrine. In vitro resistance testing was performed with samples directly derived from the patient and after 24 and 48 hours of culturing. In repeated tests an in vitro resistance to quinine could be confirmed (IC50: 25.6 x 10(-6) mol/l, IC99: > 51.2 x 10(-6) mol/l) while the strain was fully susceptible to chloroquine (IC50: < 0.4 x 10(-6) mol/l, IC99: 1.6 x 10(-6) mol/l), mefloquine (IC50: < 0.4 x 10(-6) mol/l, IC99: 3.2 x 10(-6) mol/l), tetracycline (IC50: 0.16 x 10(-6) mol/l, IC99: 0.32 x 10(-6) mol/l) and halofantrine (IC50: 0.02 x 10(-6) mol/l, IC99: 0.04 x 10(-6) mol/l). Increased susceptibility to quinine after addition of verapamil was noted. The presence of a specific mutation, on the pfmdr1-gene on chromosome 5, previously associated with chloroquine drug resistance, could be confirmed by polymerase chain reaction. To our knowledge a R III-in vivo and in vitro resistance of Plasmodium falciparum to quinine has not been described yet in East Africa.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7631126

Jelinek, T; Schelbert, P; Lscher, T; Eichenlaub, D

1995-03-01

104

A spring forward for hominin evolution in East Africa.  

PubMed

Groundwater is essential to modern human survival during drought periods. There is also growing geological evidence of springs associated with stone tools and hominin fossils in the East African Rift System (EARS) during a critical period for hominin evolution (from 1.8 Ma). However it is not known how vulnerable these springs may have been to climate variability and whether groundwater availability may have played a part in human evolution. Recent interdisciplinary research at Olduvai Gorge, Tanzania, has documented climate fluctuations attributable to astronomic forcing and the presence of paleosprings directly associated with archaeological sites. Using palaeogeological reconstruction and groundwater modelling of the Olduvai Gorge paleo-catchment, we show how spring discharge was likely linked to East African climate variability of annual to Milankovitch cycle timescales. Under decadal to centennial timescales, spring flow would have been relatively invariant providing good water resource resilience through long droughts. For multi-millennial periods, modelled spring flows lag groundwater recharge by 100 s to 1000 years. The lag creates long buffer periods allowing hominins to adapt to new habitats as potable surface water from rivers or lakes became increasingly scarce. Localised groundwater systems are likely to have been widespread within the EARS providing refugia and intense competition during dry periods, thus being an important factor in natural selection and evolution, as well as a vital resource during hominin dispersal within and out of Africa. PMID:25207544

Cuthbert, Mark O; Ashley, Gail M

2014-01-01

105

A Spring Forward for Hominin Evolution in East Africa  

PubMed Central

Groundwater is essential to modern human survival during drought periods. There is also growing geological evidence of springs associated with stone tools and hominin fossils in the East African Rift System (EARS) during a critical period for hominin evolution (from 1.8 Ma). However it is not known how vulnerable these springs may have been to climate variability and whether groundwater availability may have played a part in human evolution. Recent interdisciplinary research at Olduvai Gorge, Tanzania, has documented climate fluctuations attributable to astronomic forcing and the presence of paleosprings directly associated with archaeological sites. Using palaeogeological reconstruction and groundwater modelling of the Olduvai Gorge paleo-catchment, we show how spring discharge was likely linked to East African climate variability of annual to Milankovitch cycle timescales. Under decadal to centennial timescales, spring flow would have been relatively invariant providing good water resource resilience through long droughts. For multi-millennial periods, modelled spring flows lag groundwater recharge by 100 s to 1000 years. The lag creates long buffer periods allowing hominins to adapt to new habitats as potable surface water from rivers or lakes became increasingly scarce. Localised groundwater systems are likely to have been widespread within the EARS providing refugia and intense competition during dry periods, thus being an important factor in natural selection and evolution, as well as a vital resource during hominin dispersal within and out of Africa. PMID:25207544

Cuthbert, Mark O.; Ashley, Gail M.

2014-01-01

106

Effects of crossbreeding East African, Galla and Boer goats on body size, growth rate and kid survivability in Kenya  

E-print Network

Station, Kenya were used foz the study of body size, growth rate and kid survivability of meat goats. The study chazacters were adjusted for fixed effects of year of birth, month of birth, sex and dam age at birth. Actual age at weaning was included... AGR than the Galla for growth intervals between 4 mo to 9 mo, The East African had a higher fraction of kid survival from birth to weaning (. 96) compared to the Galla (. 85) and the Boer ( 78) The Boer additive direct effects were positive...

Angwenyi, Geoffrey Noah

2012-06-07

107

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. PMID:24000820

2013-01-01

108

Contrasting long-term records of biomass burning in wet and dry savannas of equatorial East Africa.  

PubMed

Rainfall controls fire in tropical savanna ecosystems through impacting both the amount and flammability of plant biomass, and consequently, predicted changes in tropical precipitation over the next century are likely to have contrasting effects on the fire regimes of wet and dry savannas. We reconstructed the long-term dynamics of biomass burning in equatorial East Africa, using fossil charcoal particles from two well-dated lake-sediment records in western Uganda and central Kenya. We compared these high-resolution (5 years/sample) time series of biomass burning, spanning the last 3800 and 1200 years, with independent data on past hydroclimatic variability and vegetation dynamics. In western Uganda, a rapid (<100 years) and permanent increase in burning occurred around 2170 years ago, when climatic drying replaced semideciduous forest by wooded grassland. At the century time scale, biomass burning was inversely related to moisture balance for much of the next two millennia until ca. 1750 ad, when burning increased strongly despite regional climate becoming wetter. A sustained decrease in burning since the mid20th century reflects the intensified modern-day landscape conversion into cropland and plantations. In contrast, in semiarid central Kenya, biomass burning peaked at intermediate moisture-balance levels, whereas it was lower both during the wettest and driest multidecadal periods of the last 1200 years. Here, burning steadily increased since the mid20th century, presumably due to more frequent deliberate ignitions for bush clearing and cattle ranching. Both the observed historical trends and regional contrasts in biomass burning are consistent with spatial variability in fire regimes across the African savanna biome today. They demonstrate the strong dependence of East African fire regimes on both climatic moisture balance and vegetation, and the extent to which this dependence is now being overridden by anthropogenic activity. PMID:24677504

Colombaroli, Daniele; Ssemmanda, Immaculate; Gelorini, Vanessa; Verschuren, Dirk

2014-09-01

109

Energy system development in Africa : the case of grid and off-grid power in Kenya  

E-print Network

This research used a combination of a grounded theory approach and system dynamics to study the electric power system in Kenya and to model the feedback at work in the development of the system. The ethnographic study ...

Steel, Katherine Deaton

2008-01-01

110

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

111

Widespread Pyrethroid and DDT Resistance in the Major Malaria Vector Anopheles funestus in East Africa Is Driven by Metabolic Resistance Mechanisms  

PubMed Central

Background Establishing the extent, geographical distribution and mechanisms of insecticide resistance in malaria vectors is a prerequisite for resistance management. Here, we report a widespread distribution of insecticide resistance in the major malaria vector An. funestus across Uganda and western Kenya under the control of metabolic resistance mechanisms. Methodology/Principal Findings Female An. funestus collected throughout Uganda and western Kenya exhibited a Plasmodium infection rate between 4.2 to 10.4%. Widespread resistance against both type I (permethrin) and II (deltamethrin) pyrethroids and DDT was observed across Uganda and western Kenya. All populations remain highly susceptible to carbamate, organophosphate and dieldrin insecticides. Knockdown resistance plays no role in the pyrethroid and DDT resistance as no kdr mutation associated with resistance was detected despite the presence of a F1021C replacement. Additionally, no signature of selection was observed on the sodium channel gene. Synergist assays and qRT-PCR indicated that metabolic resistance plays a major role notably through elevated expression of cytochrome P450s. DDT resistance mechanisms differ from West Africa as the L119F-GSTe2 mutation only explains a small proportion of the genetic variance to DDT resistance. Conclusion The extensive distribution of pyrethroid and DDT resistance in East African An. funestus populations represents a challenge to the control of this vector. However, the observed carbamate and organophosphate susceptibility offers alternative solutions for resistance management. PMID:25333491

Mulamba, Charles; Riveron, Jacob M.; Ibrahim, Sulaiman S.; Irving, Helen; Barnes, Kayla G.; Mukwaya, Louis G.; Birungi, Josephine; Wondji, Charles S.

2014-01-01

112

Holocene TEX86 temperature reconstructions from Lake Turkana, East Africa  

NASA Astrophysics Data System (ADS)

We present new high resolution Holocene lake surface temperature records from Lake Turkana, East Africa. These two TEX86 reconstructions, from the northern and southern basins of the lake, capture ~90 year resolution of climate patterns seen in this closed-basin system, as well as the thermal water dynamics between the two basins. The modern lake experiences surface temperatures in the northern basin ~1-3 C warmer than the southern basin, due to upwelling in the southern basin induced by the predominant southerly winds. The paleotemperature records show parallel trends to this modern basinal temperature gradient, averaging ~1.5 C warmer in the northern basin than the southern during the ~2000 years of record overlap (~450-2500 ybp). Some temperature intervals with coverage in both basins show strong agreement (i.e. ~2600-2000 Cal ybp), whereas increased wind-generated upwelling events may be responsible for periods that appear strongly antiphased (i.e. 2000-1600 Cal ybp) between basins. There does not appear to be any evidence of warming into the Medieval Warm Period (MWP, ~800-1200AD) or cooling at the start of the Little Ice Age (LIA, ~600 ybp). The southern basin temperature record indicates a substantial ~5 C warming culminating in a thermal maximum ~5ka, immediately followed by ~3 C cooling. This supports previous observations of an anomalously warm interval ~5ka documented in lake surface temperature records from Lakes Malawi and Tanganyika. A similar Holocene thermal maximum ~5ka has also been described from the Indian Ocean off the coast of Somalia (311N, 5026E) (Bard et al., 1997). The abundance of these records now point to this being the warmest or one of the warmest intervals in the Holocene in tropical East Africa and indicates this may be a widespread regional climate response. Although these temperature trends appear reasonable, overall TEX86 temperatures for Lake Turkana are considerably lower than modern surface water temperatures. Present surface temperatures in Lake Turkana have a seasonal range from ~25.5-31 C while TEX86 paleotemperatures are ~20-27 C. An explanation for this difference is not yet known; it may be due to ecological characteristics of the Lake Turkana Crenarchaeota population that are not yet understood.

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

2009-12-01

113

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

114

Long-term variability and rainfall control of savanna fire regimes in equatorial East Africa  

E-print Network

Long-term variability and rainfall control of savanna fire regimes in equatorial East Africa D A V Abstract Fires burning the vast grasslands and savannas of Africa significantly influence the global carbon regimes. To examine climate­vegetation­fire linkages in dry savanna, we conducted macroscopic

Hu, Feng Sheng

115

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

116

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

117

A new cryptic Dainty Frog from East Africa (Anura: Ranidae: Cacosternum)  

Microsoft Academic Search

We describe a new species of dainty frog in the genus Cacosternum (Ranidae) from East Africa. It is similar morphologically to Cacosternum boettgeri from the interior of southern Africa, and is distinguished on the basis of an advertisement call with double or treble pulsed notes. Skeletal and DNA sequence differences support the species status of this taxon. It is known

Alan Channing; Caroline Brun; Marius Burger; Severine Febvre; David Moyer

2005-01-01

118

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. PMID:24802260

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

119

Complete Genome Sequences of Lineage III Peste des Petits Ruminants Viruses from the Middle East and East Africa  

PubMed Central

For the first time, complete genome sequences of four lineage III peste des petits ruminants (PPR) viruses (Oman 1983, United Arab Emirates 1986, Ethiopia 1994, and Uganda 2012) originated from the Middle East and East Africa are reported here. The availability of complete genome sequences from all four lineages (I to IV) of the PPR virus (PPRV) would greatly help in a comprehensive understanding of the molecular evolution and emergence of PPRV. PMID:25342675

Muniraju, Murali; Munir, Muhammad; Banyard, Ashley C.; Ayebazibwe, Chrisostom; Wensman, Jonas; Zohari, Siamak; Berg, Mikael; Parthiban, AravindhBabu R.; Mahapatra, Mana; Libeau, Genevive; Batten, Carrie

2014-01-01

120

Complete Genome Sequences of Lineage III Peste des Petits Ruminants Viruses from the Middle East and East Africa.  

PubMed

For the first time, complete genome sequences of four lineage III peste des petits ruminants (PPR) viruses (Oman 1983, United Arab Emirates 1986, Ethiopia 1994, and Uganda 2012) originated from the Middle East and East Africa are reported here. The availability of complete genome sequences from all four lineages (I to IV) of the PPR virus (PPRV) would greatly help in a comprehensive understanding of the molecular evolution and emergence of PPRV. PMID:25342675

Muniraju, Murali; Munir, Muhammad; Banyard, Ashley C; Ayebazibwe, Chrisostom; Wensman, Jonas; Zohari, Siamak; Berg, Mikael; Parthiban, AravindhBabu R; Mahapatra, Mana; Libeau, Genevive; Batten, Carrie; Parida, Satya

2014-01-01

121

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 1422 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. PMID:24400011

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

2013-01-01

122

Drought-associated chikungunya emergence along coastal East Africa  

Technology Transfer Automated Retrieval System (TEKTRAN)

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 ecoclimatic conditions associated wit...

123

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

124

A multivariate approach for persistence-based drought prediction: Application to the 20102011 East Africa drought  

E-print Network

A multivariate approach for persistence-based drought prediction: Application to the 2010­2011 East Africa drought Amir AghaKouchak Center for Hydrometeorology and Remote Sensing, Department of Civil-2175, USA a r t i c l e i n f o Article history: Available online xxxx Keywords: Drought prediction East

AghaKouchak, Amir

125

Forecast and Validation of the Rift Valley fever outbreak in East Africa: 2006-2007  

Technology Transfer Automated Retrieval System (TEKTRAN)

Background The instantaneous occurrence of El Nino / Southern Oscillation (ENSO) warm events and anomalous warming of the equatorial western Indian Ocean (WIO) are associated with elevated and widespread rainfall over East Africa. Such, sustained, heavy rainfall in East is associated with the emerg...

126

Near East and North Africa: An Annotated List of Materials for Children.  

ERIC Educational Resources Information Center

This is an annotated bibliography of materials appropriate for kindergarten through ninth grade children. The Near East as used here is all of North Africa, the Arabian Penninsula, Iran, Afghanistan, Greece, and Turkey. A section is devoted to each nation with some of the works in the native languages of the Near East. They include nonfiction,

State Univ. of New York, Ithaca. School of Hotel Administration at Cornell Univ.

127

Smart Boards to Chalkboards: Professional Development for Early Childhood Teachers in Rural East Africa  

ERIC Educational Resources Information Center

The purpose of this study was to examine the teaching strategies of early childhood development teachers in rural East Africa. Teams of early childhood educators from the United States presented professional development conferences for East African Early Childhood Development teachers during the summers of 2007 and 2008. The conferences introduced

Williams, Jeanne

2012-01-01

128

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

129

Palaeolimnology and archaeology of Holocene deposits north-east of Lake Turkana, Kenya  

Microsoft Academic Search

Geological, diatom, pollen and archaeological studies, supported by 24 original radiocarbon dates, provide new evidence to illustrate the Holocene history of Lake Turkana, Kenya. High and intermediate lake levels are recorded between 10,000 and about 3,000 yr BP, with a general regression during the later Holocene. Archaeological finds document the transition from a fishing-based economy to pastoralism.

R. B. Owen; J. W. Barthelme; R. W. Renaut; A. Vincens

1982-01-01

130

Hypovitaminosis D in the Middle East and North Africa  

PubMed Central

Background: The Middle East and North Africa (MENA) region registers some of the highest rates of hypovitaminosis D worldwide. Aim: We systematically reviewed the prevalence of hypovitaminosis D, rickets and osteomalacia, their predictors and impact on major outcomes, in the region. Methods: Medline, Pubmed and Embase search engines, entering keywords and concepts, combined with individual countries of interest, were used. Search was limited years 20002012; and review articles were used for the period preceding year 2000. Results: Rickets and osteomalacia still occur in this sunny region. Hypovitaminosis D prevails, with rates varying 3090%, considering a desirable serum 25 hydroxy-vitamin D [25(OH)D] of 20 ng/ml. Advancing age, female gender, multi-parity, clothing style, season, socio-economic status and urban living are recognized predictors of hypovitaminosis D in adults. Prolonged breastfeeding without vitamin D supplementation and low dietary calcium intake are the recognized risk factors for rickets and hypovitaminosis D in children.. Associations with pain score and disease activity in rheumatologic disorders, viral load and interleukins in hepatitis C, BMI, lipids and insulin sensitivity, blood pressure, heart failure and mortality are described. Sun exposure in adults decreased prevalence of metabolic syndrome in one study. Few randomized vitamin D trials revealed that the majority of mothers or children failed to achieve a desirable 25(OH)D level, even with doses by far exceeding current recommendations. A trial in adolescent girls reveals substantial bone and lean mass increments. Conclusion: Hypovitaminosis D is prevalent in MENA. The lack of populations based studies, gaps in studies in infants, pre-pubertal children and pregnant women, hinder the development of region specific guidelines and constitute a major obstacle to impact this chronic and most often subclinical disease. PMID:24194968

Bassil, Darina; Rahme, Maya; Hoteit, Maha; Fuleihan, Ghada El-Hajj

2013-01-01

131

Predicting distribution of Aedes aegypti and Culex pipiens complex, potential vectors of Rift Valley fever virus in relation to disease epidemics in East Africa  

PubMed Central

Background The East African region has experienced several Rift Valley fever (RVF) outbreaks since the 1930s. The objective of this study was to identify distributions of potential disease vectors in relation to disease epidemics. Understanding disease vector potential distributions is a major concern for disease transmission dynamics. Methods Diverse ecological niche modelling techniques have been developed for this purpose: we present a maximum entropy (Maxent) approach for estimating distributions of potential RVF vectors in un-sampled areas in East Africa. We modelled the distribution of two species of mosquitoes (Aedes aegypti and Culex pipiens complex) responsible for potential maintenance and amplification of the virus, respectively. Predicted distributions of environmentally suitable areas in East Africa were based on the presence-only occurrence data derived from our entomological study in Ngorongoro District in northern Tanzania. Results Our model predicted potential suitable areas with high success rates of 90.9% for A. aegypti and 91.6% for C. pipiens complex. Model performance was statistically significantly better than random for both species. Most suitable sites for the two vectors were predicted in central and northwestern Tanzania with previous disease epidemics. Other important risk areas include western Lake Victoria, northern parts of Lake Malawi, and the Rift Valley region of Kenya. Conclusion Findings from this study show distributions of vectors had biological and epidemiological significance in relation to disease outbreak hotspots, and hence provide guidance for the selection of sampling areas for RVF vectors during inter-epidemic periods. PMID:24137533

Mweya, Clement Nyamunura; Kimera, Sharadhuli Iddi; Kija, John Bukombe; Mboera, Leonard E. G.

2013-01-01

132

U-series Chronology of volcanoes in the Central Kenya Peralkaline Province, East African Rift  

NASA Astrophysics Data System (ADS)

We are studying the East African Rift System (EARS) in the Central Kenya Peralkaline Province (CKPP), and specifically the young volcanoes Mt. Suswa, Longonot, and Menengai. Ar dates by Al Deino on K-feldspar phenocrysts show a strong correlation between older Ar ages and decreasing 230Th/232Th, which we interpret to reflect the age of eruption. This system has been the subject of recent research done by several UTEP alumni including Antony Wamalwa using potential field and magnetotelluric (MT) data to identify and characterize fractures and hydrothermal fluids. Also research on geochemical modeling done by John White, Vanessa Espejel and Peter Omenda led to the hypothesis of possible disequilibrium in these young, mainly obsidian samples in their post eruptive history. A pilot study of 8 samples, (also including W-2a USGS standard and a blank) establish the correlation that was seen between the ages found by Deino along with the 230/232Th ratios. All 8 samples from Mt. Suswa showed a 234U/238U ratio of (1) which indicates secular equilibrium or unity and that these are very fresh samples with no post-eruptive decay or leaching of U isotopes. The pilot set was comprised of four samples from the ring-trench group (RTG) with ages ranging from 7ka-present, two samples from the post-caldera stage ranging from 31-10ka, one sample from the syn-caldera stage dated at 41ka, and one sample from the pre-caldera stage dated at 112ka. The young RTG had a 230/232Th fractionation ratio of 0.8 ranging to the older pre-caldera stage with a 230/232Th ratio of 0.6. From this current data and research of 14C ages by Nick Rogers, the data from Longonot volcano was also similar to the 230/232Th ratio we found. Rogers' data places Longonot volcano ages to be no more than 20ka with the youngest samples also roughly around 0.8 disequilibrium. These strong correlations between the pilot study done for Mt. Suswa, 40Ar ages by Deino, along with 14C ages from Rogers have led to the exploration of present U-series data set of the youngest samples from the rest of the CKPP volcanoes including: Menengai, more from Longonot, and Olkaria. And since it is observed that there is the presence of lateral migration along an axial dike swarm that has operated in other parts of the EARS, we have chosen to run samples from the adjacent mafic fields of Elmenteita, Tandamara, and Ndabibi to see if there is a trend in the correlation of the 230/232Th ratios at the time of eruption as well as observing how close these samples get to unity. This would answer questions as to whether similar 230/232Th ratios imply that the mafic fields feed the calderas.

Negron, L. M.; Ma, L.; Deino, A.; Anthony, E. Y.

2012-12-01

133

High prevalence of Rickettsia africae variants in Amblyomma variegatum ticks from domestic mammals in rural western Kenya: implications for human health.  

PubMed

Tick-borne spotted fever group (SFG) rickettsioses are emerging human diseases caused by obligate intracellular Gram-negative bacteria of the genus Rickettsia. Despite being important causes of systemic febrile illnesses in travelers returning from sub-Saharan Africa, little is known about the reservoir hosts of these pathogens. We conducted surveys for rickettsiae in domestic animals and ticks in a rural setting in western Kenya. Of the 100 serum specimens tested from each species of domestic ruminant 43% of goats, 23% of sheep, and 1% of cattle had immunoglobulin G (IgG) antibodies to the SFG rickettsiae. None of these sera were positive for IgG against typhus group rickettsiae. We detected Rickettsia africae-genotype DNA in 92.6% of adult Amblyomma variegatum ticks collected from domestic ruminants, but found no evidence of the pathogen in blood specimens from cattle, goats, or sheep. Sequencing of a subset of 21 rickettsia-positive ticks revealed R. africae variants in 95.2% (20/21) of ticks tested. Our findings show a high prevalence of R. africae variants in A. variegatum ticks in western Kenya, which may represent a low disease risk for humans. This may provide a possible explanation for the lack of African tick-bite fever cases among febrile patients in Kenya. PMID:25325312

Maina, Alice N; Jiang, Ju; Omulo, Sylvia A; Cutler, Sally J; Ade, Fredrick; Ogola, Eric; Feikin, Daniel R; Njenga, M Kariuki; Cleaveland, Sarah; Mpoke, Solomon; Ng'ang'a, Zipporah; Breiman, Robert F; Knobel, Darryn L; Richards, Allen L

2014-10-01

134

High Prevalence of Rickettsia africae Variants in Amblyomma variegatum Ticks from Domestic Mammals in Rural Western Kenya: Implications for Human Health  

PubMed Central

Abstract Tick-borne spotted fever group (SFG) rickettsioses are emerging human diseases caused by obligate intracellular Gram-negative bacteria of the genus Rickettsia. Despite being important causes of systemic febrile illnesses in travelers returning from sub-Saharan Africa, little is known about the reservoir hosts of these pathogens. We conducted surveys for rickettsiae in domestic animals and ticks in a rural setting in western Kenya. Of the 100 serum specimens tested from each species of domestic ruminant 43% of goats, 23% of sheep, and 1% of cattle had immunoglobulin G (IgG) antibodies to the SFG rickettsiae. None of these sera were positive for IgG against typhus group rickettsiae. We detected Rickettsia africaegenotype DNA in 92.6% of adult Amblyomma variegatum ticks collected from domestic ruminants, but found no evidence of the pathogen in blood specimens from cattle, goats, or sheep. Sequencing of a subset of 21 rickettsia-positive ticks revealed R. africae variants in 95.2% (20/21) of ticks tested. Our findings show a high prevalence of R. africae variants in A. variegatum ticks in western Kenya, which may represent a low disease risk for humans. This may provide a possible explanation for the lack of African tick-bite fever cases among febrile patients in Kenya. PMID:25325312

Maina, Alice N.; Jiang, Ju; Omulo, Sylvia A.; Cutler, Sally J.; Ade, Fredrick; Ogola, Eric; Feikin, Daniel R.; Njenga, M. Kariuki; Cleaveland, Sarah; Mpoke, Solomon; Ng'ang'a, Zipporah; Breiman, Robert F.; Knobel, Darryn L.

2014-01-01

135

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

136

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

137

Anomalously wet and dry rainy seasons in Equatorial East Africa and associated differences in intra-seasonal characteristics  

NASA Astrophysics Data System (ADS)

Differences between anomalously wet and dry rainy seasons over the period 1961-2001 in Equatorial East Africa (Kenya, northern Tanzania) are studied at local scale using a 53 rain-gauge network and analysing six intra-seasonal characteristics (ISCs): the onset and end dates, the wet spells number and length, daily mean rainfall amount and the dry spells length. As compared to anomalously dry Long Rains, anomalously wet ones record earlier onsets, more wet spells with higher daily mean rainfall amounts (above 14 mm/day). For the Short Rains, the end date is also widely modulated across the rain gauge network, and daily mean rainfall amounts above (below) 10 mm/day are more (less) frequent during anomalously wet (dry) seasons. The differences in the number, length and daily mean rainfall amount of wet spells between anomalously wet and anomalously dry rainy seasons is also analysed in an ensemble of 24 sea surface temperature-forced runs of the ECHAM4.5 Atmospheric General Circulation Model. For the Long Rains, results are inconsistent between runs which suggests a lack of reproducibility of the ISCs in the model. For the Short Rains, the ISCs distributions between anomalously wet and anomalously dry years are significantly different in most of the runs/locations. In particular, daily mean rainfall amounts above 8 mm/day are more (less) frequent in the model during anomalously wet (dry) years.

Philippon, N.; Camberlin, P.; Moron, V.; Boyard-Micheau, J.

2015-01-01

138

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

139

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

140

Retrospective observations on the geographical relationship between Rhipicephalus appendiculatus and East Coast fever in southern Africa.  

PubMed

East Coast fever appeared in southern Africa in 1902, after the importation of cattle from East Africa, and spread throughout the range of Rhipicephalus appendiculatus until it reached the southern limit of distribution of this tick in 1916. It was progressively eradicated by quarantine, destocking, slaughter and frequent dipping in arsenic. The last case occurred in Swaziland in 1960. A computer based system for matching climates and ecology (CLIMEX) revealed a direct correlation between the climatic favorability of different areas for the tick and the time required to eradicate the disease. PMID:2031290

Lawrence, J A

1991-02-23

141

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 030'S and 100'S. It is bounded on the east by longitude 3430'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 Gy h(-1), and the mean is 2.3 Gy 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

142

Twenty-five years of geodetic measurements along the Tadjoura-Asal rift system, Djibouti, East Africa  

E-print Network

years of geodetic measurements along the Tadjoura-Asal rift system, Djibouti, East Africa, J. GeophysTwenty-five years of geodetic measurements along the Tadjoura- Asal rift system, Djibouti, East Africa Christophe Vigny,1 Jean-Bernard de Chabalier,2 Jean-Claude Ruegg,2 Philippe Huchon,3 Kurt L. Feigl

Vigny, Christophe

143

Learning Large-Scale Dynamic Discrete Choice Models of Spatio-Temporal Preferences with Application to Migratory Pastoralism in East Africa  

E-print Network

to Migratory Pastoralism in East Africa Stefano Ermon Stanford University ermon@cs.stanford.edu Yexiang Xue pastoralism in East Africa and that it considerably outperforms other approaches on a large- scale real

Bejerano, Gill

144

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

145

Geopolitical influences on German development policies in Africa and AIDS policies in Kenya  

E-print Network

-abiding. Many African countries do not fulfill those conditions. Extremely high prevalence rates of HIV/AIDS in Africa severely undermine social structure, economic development and political stability and thus contribute to state failure. State failure...

Bachmann, Veit

2009-06-02

146

DAVIS, NEIL NATHANIEL. Dynamic and Stochastic Modeling of Various Components of the Hydrological Cycle for East Africa. (Under the direction of Fredrick Semazzi.)  

E-print Network

of the Hydrological Cycle for East Africa. (Under the direction of Fredrick Semazzi.) This research has investigated the ability to model precipitation over East Africa using the RegCM regional climate model, and the ability compared to determine which performed best for East Africa. Additionally the micro- physical scheme SUBEX

Liu, Paul

147

The effects of HIV and AIDS on fertility in East and Central Africa  

Microsoft Academic Search

Concern has been expressed about the fertility of people infected with HIV: the worry has been that on learning of their condition, HIV-affected individuals may attempt to accomplish unmet reproductive goals knowing that they will not live a normal life span. This article addresses the potential effects of AIDS on fertility and reproductive decisions in East and Central Africa. The

Philip Setel

1995-01-01

148

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

149

Pleistocene desiccation in East Africa bottlenecked but did not extirpate the adaptive radiation  

E-print Network

of Lake Victoria haplochromine cichlid fishes Kathryn R. Elmera,1 , Chiara Reggioa,1 , Thierry Wirtha,2 March 3, 2009) The Great Lakes region of East Africa, including Lake Victoria, is the center, within that lake basin or elsewhere, from which Lake Victoria was recolonized. We studied the population

Wirth, Thierry

150

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

151

Near East and North Africa: A Selected Functional and Country Bibliography.  

ERIC Educational Resources Information Center

This selected bibliography focuses on the Near East and North Africa. Among the topics covered are: Documentary Collections, History, Politics, and International Relations, Islam and the Islamic World, the Arabs, Geography, Art, Literature, Education and Sociocultural Patterns, and Economics, Labor and Oil. An introduction to the series is in SO

Foreign Service (Dept. of State), Washington, DC. Foreign Service Inst.

152

Revolution and Journalism Higher Education in the Middle East/North Africa Region  

ERIC Educational Resources Information Center

The disruptions brought by the Arab Spring revolutions in the Middle East/North Africa (MENA) region in 2010-2011 created a series of personal and professional challenges for those involved in higher education in journalism in the region. This research uses narrative inquiry to examine the impact revolution had on a group of educators in the MENA

Schafer, Shaun T.

2012-01-01

153

Biology of Octopus vulgaris off the east coast of South Africa  

Microsoft Academic Search

The biology of Octopus vulgaris Cuvier inhabiting subtropical littoral reefs off the east coast of South Africa was investigated. Analyses of stomach contents and lair middens revealed that the mussel Perna perna was the dominant food organism. Growth rate of captive individuals was higher than has previously been recorded but food conversion was lower. Females became sexually mature at 900

M. J. Smale; P. R. Buchan

1981-01-01

154

Meat-feasting Sites and Cattle Brands: Patterns of Rock-shelter Utilization in East Africa  

Microsoft Academic Search

Dr. Gramly has been working on the origins and development of East Africa's first food-producers. He is presently on the staff of the State University of New York at Stony Brook. In this article he describes excavations at two nineteenth century pastoral Masai sites and suggests an approach for tracing Maa-speaking pastoralists in the archaeological record.

Richard Michael Gramly

1975-01-01

155

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

156

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

157

Capacity-building requirements for e-records management : The case in East and Southern Africa  

Microsoft Academic Search

Purpose This article aims to examine capacity building requirements for e-records management in East and Southern Africa. It argues that e-records management poses a number of problems and challenges that include but are not limited to: lack of skills and competencies, inadequate resources, lack of awareness among government authorities and records professionals, fragility of media and the need for

Justus Wamukoya; Stephen M. Mutula

2005-01-01

158

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

159

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 6.81.0C from the LGM to the present, with mid-Holocene temperatures 1.60.9C 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

160

GEOGYNAMICAL SETTING OF THE VIRUNGA VOLCANIC PROVINCE, EAST AFRICA  

Microsoft Academic Search

The mid-Miocene-recently active Virunga volcanic province lies along the northwestern side of the broad, uplifted East African Plateau, which, like the Ethiopian Plateau to the north, is underlain by anomalously hot asthenosphere. We review mechanisms proposed to explain the geological, geophysical, and geochemical characteristics of the uplifted plateaux, providing a geodynamical framework for the active volcanoes of the Virunga volcanic

Cynthia Ebinger; Tanya Furman

161

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

162

Revolutionary Movements in the Middle East and North Africa  

E-print Network

Affairs, The New York Times, Harvard Middle Eastern and Islamic Review, Middle East Policy, and Turkish Insight. He is developing a program on Islam, entrepreneurship, and democracy at UC Berkeley. Thursdays This course examines the boundaries of whiteness at both extremes--the color line, which intends

Walker, Matthew P.

163

Trace element and Sr-Nd-Pb isotope geochemistry of Rungwe Volcanic Province, Tanzania: Implications for a superplume source for East Africa Rift magmatism  

NASA Astrophysics Data System (ADS)

The recently discovered high, plume-like 3He/4He ratios at Rungwe Volcanic Province (RVP) in southern Tanzania, similar to those at the Main Ethiopian Rift in Ethiopia, strongly suggest that magmatism associated with continental rifting along the entire East African Rift System (EARS) has a deep mantle contribution (Hilton et al., 2011). New trace element and Sr-Nd-Pb isotopic data for high 3He/4He lavas and tephras from RVP can be explained by binary mixing relationships involving Early Proterozoic (+/- Archaean) lithospheric mantle, present beneath the southern EARS, and a volatile-rich carbonatitic plume with a limited range of compositions and best represented by recent Nyiragongo lavas from the Virunga Volcanic Province also in the Western Rift. Other lavas from the Western Rift and from the southern Kenya Rift can also be explained through mixing between the same endmember components. In contrast, lavas from the northern Kenya and Main Ethiopian rifts can be explained through variable mixing between the same mantle plume material and the Middle to Late Proterozoic lithospheric mantle, present beneath the northern EARS. Thus, we propose that the bulk of EARS magmatism is sourced from mixing among three endmember sources: Early Proterozoic (+/- Archaean) lithospheric mantle, Middle to Late Proterozoic lithospheric mantle and a volatile-rich carbonatitic plume with a limited range of compositions. We propose further that the African Superplume, a large, seismically anomalous feature originating in the lower mantle beneath southern Africa, influences magmatism throughout eastern Africa with magmatism at RVP and Main Ethiopian Rift representing two different heads of a single mantle plume source. This is consistent with a single mantle plume origin of the coupled He-Ne isotopic signatures of mantle-derived xenoliths and/or lavas from all segments of the EARS (Halldorsson et al., 2014).

Castillo, Paterno; Hilton, David; Halldrsson, Smundur

2014-09-01

164

Genome-wide analysis reveals the ancient and recent admixture history of East African Shorthorn Zebu from Western Kenya  

PubMed Central

The Kenyan East African zebu cattle are valuable and widely used genetic resources. Previous studies using microsatellite loci revealed the complex history of these populations with the presence of taurine and zebu genetic backgrounds. Here, we estimate at genome-wide level the genetic composition and population structure of the East African Shorthorn Zebu (EASZ) of western Kenya. A total of 548 EASZ from 20 sub-locations were genotyped using the Illumina BovineSNP50 v. 1 beadchip. STRUCTURE analysis reveals admixture with Asian zebu, African and European taurine cattle. The EASZ were separated into three categories: substantial (?12.5%), moderate (1.56%

Mbole-Kariuki, M N; Sonstegard, T; Orth, A; Thumbi, S M; Bronsvoort, B M de C; Kiara, H; Toye, P; Conradie, I; Jennings, A; Coetzer, K; Woolhouse, M E J; Hanotte, O; Tapio, M

2014-01-01

165

Genome-wide analysis reveals the ancient and recent admixture history of East African Shorthorn Zebu from Western Kenya.  

PubMed

The Kenyan East African zebu cattle are valuable and widely used genetic resources. Previous studies using microsatellite loci revealed the complex history of these populations with the presence of taurine and zebu genetic backgrounds. Here, we estimate at genome-wide level the genetic composition and population structure of the East African Shorthorn Zebu (EASZ) of western Kenya. A total of 548 EASZ from 20 sub-locations were genotyped using the Illumina BovineSNP50 v. 1 beadchip. STRUCTURE analysis reveals admixture with Asian zebu, African and European taurine cattle. The EASZ were separated into three categories: substantial (?12.5%), moderate (1.56%

Mbole-Kariuki, M N; Sonstegard, T; Orth, A; Thumbi, S M; Bronsvoort, B M de C; Kiara, H; Toye, P; Conradie, I; Jennings, A; Coetzer, K; Woolhouse, M E J; Hanotte, O; Tapio, M

2014-10-01

166

Harnessing Africa's sun: China and the development of solar energy in Kenya  

Microsoft Academic Search

Africa has immense energy challenges, characterised by low rates of access to electricity, irregularities and a general shortage in electricity supply. Solar energy provides African governments with the opportunity to address these challenges. With an average quantity of five to six kilowatts of power from the sun per square metre per day, the continent has vast potential for producing energy

Tsidiso Disenyana

2009-01-01

167

Four-million-year-old hominids from East Lake Turkana, Kenya.  

PubMed

A piece of mandible and several isolated teeth are reported from fluviatile sediments older than 4 million years at East Lake Turkana. They most closely resemble hominids from Laetoli, Tanzania and Hadar, Ethiopia which have been assigned to Australopithecus afarensis. PMID:8141242

Coffing, K; Feibel, C; Leakey, M; Walker, A

1994-01-01

168

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. Antn; I. McDougall; C. Kiarie; F. K. Manthi; L. N. Leakey

2007-01-01

169

Public Policy and the Management of Higher Education in Sub-Saharan Africa: The Case of Kenya.  

ERIC Educational Resources Information Center

Examines Kenya's policy concerning growth and development of higher education over the last 20 years. Concludes that Kenya has problems of infrastructure quality and physical plant similar to those of other Sub-Saharan African countries, that resource allocation policies are inconsistent, and that expansion should be guided by popular demand for

Gray, Kenneth R.; Credle, Sid Howard

1996-01-01

170

Abstract We used a data set of ungulate censuses from 31 natural ecosystems from East and Southern Africa to  

E-print Network

Abstract We used a data set of ungulate censuses from 31 natural ecosystems from East and Southern Africa to test two hypotheses: (1) megaherbivores should domi- nate ungulate communities in ecosystems

Illius, Andrew

171

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

PubMed

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 more frequent. In this article, we combine drought and land degradation effects into an Agricultural Drought Framework, which departs from the farmers' prioritization of drought and accommodates scientists' concern for land degradation. It includes meteorological drought, soil water drought, and soil nutrient drought. The framework increases insight into how different land degradation processes influence the vulnerability of land and farmers to drought. A focus on increased rainwater use efficiency will address both problems of land degradation and drought, thereby improving productivity and food security in semiarid East Africa. PMID:18828283

Slegers, Monique F W; Stroosnijder, Leo

2008-07-01

172

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

173

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

174

Wastewater production, treatment, and irrigation in Middle East and North Africa  

Microsoft Academic Search

The Middle East and North Africa (MENA) region is the driest region of the world with only 1% of the worlds freshwater resources.\\u000a The increasing competition for good-quality water has cut into agricultures water share but since the use of freshwater for\\u000a domestic, industrial and municipal activities generates wastewater, the volume of wastewater used in agriculture has increased.\\u000a About 43%

Manzoor Qadir; Akissa Bahri; Toshio Sato; Esmat Al-Karadsheh

2010-01-01

175

Mantle deformation during rifting: Constraints from quantitative microstructural analysis of olivine from the East African Rift (Marsabit, Kenya)  

NASA Astrophysics Data System (ADS)

Lherzolitic and harzburgitic peridotite xenoliths from the Marsabit volcanic field of the East-African Rift, Kenya, display a range of porphyroclastic to ultramylonitic textures that record intense deformation and strain localisation during decompression, cooling and exhumation of subcontinental mantle lithosphere during the early stages of continental rifting. Quantitative microstructural analysis by electron backscatter diffraction of both bulk fabrics and intragrain low-angle boundaries have been applied to these xenoliths to establish how deformation has evolved during this exhumation history. Bulk rock fabric analysis indicates the operation of (001)[100] (E-type) as the dominant slip system in the constituent olivines, with only one porphyroclastic xenolith recording the development of the classical (010)[100] (A-type) fabric. A weak E-type fabric is also present within the fine-grained matrix of the mylonitic and ultramylonitic xenoliths. Low-angle boundaries, preserved within individual olivine grains within the different xenoliths indicate the evolution of intra-grain slip systems from (010)[100] (A-slip) and (001)[100] (E-slip) in porphyroclastic peridotites, to dominant (001)[100] (E-slip) in the protomylonite and mylonite and dominant (100)[001] (C-slip) in the ultramylonite. Bulk fabric and intragrain low-angle boundary analyses are therefore concordant and indicate a systematic evolution of olivine slip systems from A-type to E-type to C-type during strain localisation associated with cooling during mantle exhumation. Both approaches confirm the dominant activity of the (001)[100] E-type slip system during rifting. However, the ultramylonites also provide the first evidence of [001] slip in such an environment. The activation of these two slip systems in olivine might be a useful indicator of an extensional rift margin setting in other peridotites.

Kaczmarek, Mary-Alix; Reddy, Steven M.

2013-11-01

176

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

177

African 2, a clonal complex of Mycobacterium bovis epidemiologically important in East Africa.  

PubMed

We have identified a clonal complex of Mycobacterium bovis isolated at high frequency from cattle in Uganda, Burundi, Tanzania, and Ethiopia. We have named this related group of M. bovis strains the African 2 (Af2) clonal complex of M. bovis. Af2 strains are defined by a specific chromosomal deletion (RDAf2) and can be identified by the absence of spacers 3 to 7 in their spoligotype patterns. Deletion analysis of M. bovis isolates from Algeria, Mali, Chad, Nigeria, Cameroon, South Africa, and Mozambique did not identify any strains of the Af2 clonal complex, suggesting that this clonal complex of M. bovis is localized in East Africa. The specific spoligotype pattern of the Af2 clonal complex was rarely identified among isolates from outside Africa, and the few isolates that were found and tested were intact at the RDAf2 locus. We conclude that the Af2 clonal complex is localized to cattle in East Africa. We found that strains of the Af2 clonal complex of M. bovis have, in general, four or more copies of the insertion sequence IS6110, in contrast to the majority of M. bovis strains isolated from cattle, which are thought to carry only one or a few copies. PMID:21097608

Berg, Stefan; Garcia-Pelayo, M Carmen; Mller, Borna; Hailu, Elena; Asiimwe, Benon; Kremer, Kristin; Dale, James; Boniotti, M Beatrice; Rodriguez, Sabrina; Hilty, Markus; Rigouts, Leen; Firdessa, Rebuma; Machado, Adelina; Mucavele, Custodia; Ngandolo, Bongo Nare Richard; Bruchfeld, Judith; Boschiroli, Laura; Mller, Annlle; Sahraoui, Naima; Pacciarini, Maria; Cadmus, Simeon; Joloba, Moses; van Soolingen, Dick; Michel, Anita L; Djnne, Berit; Aranaz, Alicia; Zinsstag, Jakob; van Helden, Paul; Portaels, Franoise; Kazwala, Rudovick; Kllenius, Gunilla; Hewinson, R Glyn; Aseffa, Abraham; Gordon, Stephen V; Smith, Noel H

2011-02-01

178

Challenges in forestry conservation in East Africa. Is community based forestry the key to forest survival? 1  

Microsoft Academic Search

East Africa's forests are rapidly declining due to pressure from population increase and other land uses. Although most of the three East African states have enabling climatic systems for forest growth, only about 10% of the land is forested. This puts so much strain to forests, that are supposed to support over 50 million people, all depending on the natural

Kunga Ngece

179

The distribution of C 3 and C 4 grasses and carbon isotope discrimination along an altitudinal and moisture gradient in Kenya  

Microsoft Academic Search

More than 500 species of the Poaceae are found in Kenya, East Africa. Eighteen of twenty-seven tribes are exclusively (except the Paniceae and Danthonieae) of the C3 photosynthetic type. A floristic analysis of low altitude grasslands suggests that nearly all species at these low altitudes are of the C4 photosynthetic type. At high altitudes, however, nearly all grasses are of

Larry L. Tieszen; Michael M. Senyimba; Simeon K. Imbamba; John H. Troughton

1979-01-01

180

When to Randomize: Lessons from Independent Impact Evaluation of Reading to Learn (RtL) Programme to Improve Literacy and Numeracy in Kenya and Uganda  

ERIC Educational Resources Information Center

In East Africa, there is great effort directed toward ensuring that there is learning and value for money invested in universal education policies initiated over the past decade. Kenya and Uganda are two countries that typify this effort. The effort includes the work of research organisations such as Uwezo, which assess learning levels; RTI, which

Oketch, Moses; Ngware, Moses; Mutisya, Maurice; Kassahun, Admassu; Abuya, Benta; Musyoka, Peter

2014-01-01

181

Seasonal changes in abundances of waterbirds at Sabaki River Mouth (Malindi, Kenya), a key stopover site on the West AsianEast African Flyway  

Microsoft Academic Search

Information on seasonal changes in waterbird numbers in coastal East Africa is limited, but crucial for estimating global flyway populations and targeting conservation efforts. The Sabaki River Mouth is an important site for waterbirds in the region. We counted waterbirds at the site monthly from April 2004 to February 2005. Our counts confirmed the importance of the site for the

Simon Valle; Luigi Boitani

2012-01-01

182

Sunspots, El Nio, 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

183

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 individuals 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. PMID:19553783

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

2011-01-01

184

Fluoride in groundwater in selected villages in Eritrea (North East Africa).  

PubMed

A study was undertaken to estimate fluoride content in the groundwater in certain parts of rural Eritrea. North-East Africa, along the River Anseba. Standard procedure was adopted for fluoride detection. Results indicate elevated concentration of fluoride in groundwater. The highest concentration was found to be 3.73 mg L(-1), well above the safety level for consumption. Geological basis for the high concentration of high fluoride has been established; it is presumed to be the pegmatite intrusion hosted by a granitic batholith. Extensive dental fluorosis has been observed in the population exposed to drinking water of high fluoride content. PMID:12002285

Srikanth, R; Viswanatham, K S; Kahsai, Fikremariam; Fisahatsion, Abraham; Asmellash, Micheal

2002-04-01

185

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

186

A survey of Echinococcus species in wild carnivores and livestock in East Africa.  

PubMed

We examined 71 faecal samples of carnivores from Queen Elizabeth National Park (QENP), Uganda, for eggs of Echinococcus species. Thirty-nine faecal samples contained taeniid eggs. For species diagnosis, DNA was isolated from a total of 1984 individual taeniid eggs. To differentiate eggs of Echinococcus felidis from other taeniid taxa (including the closely related Echinococcus granulosus sensu stricto), a restriction fragment length polymorphism (RFLP)-PCR of the mitochondrial nad1 gene was developed. As the faecal samples were taken from the environment, the host species was determined for all samples, except for one, by RFLP-PCR of the cob gene. Seven hundred and ninety-one of the 1984 eggs yielded a suitable PCR product. E. felidis was present in 34 of 47 samples from lions, none of 18 samples from leopards, and one of five samples from spotted hyenas. No Echinococcus taxon other than E. felidis was found, but three samples from lions contained eggs of Taenia regis. Two hydatid cysts of warthog origin from QENP were available for this study; molecular examination showed that one belonged to E. felidis, the other to E. granulosus (G1 strain). As a comparison of methods demonstrated that molecular diagnostic tools used for previous surveys of Echinococcus isolates in eastern Africa are not suitable to discriminate between E. felidis and E. granulosus sensu stricto, we re-examined 412 hydatid cyst samples of human, sheep, cattle, camel and goat origin from Kenya. Previous results were confirmed, as E. granulosus sensu stricto and Echinococcus canadensis G6/7 strain, but no E. felidis was found among these samples. In conclusion, we provide evidence that E. felidis is a frequent parasite of lions in Uganda, and possibly also occurs in hyenas. Additionally, we show that warthogs interact as intermediate hosts for E. felidis. We did not find evidence that E. felidis is present in eastern Africa outside conservation areas. PMID:19275902

Httner, Marion; Siefert, Ludwig; Mackenstedt, Ute; Romig, Thomas

2009-09-01

187

The importance of choice in the rollout of ARV-based prevention to user groups in Kenya and South Africa: a qualitative study  

PubMed Central

Introduction Stakeholders continue to discuss the appropriateness of antiretroviral-based pre-exposure prophylaxis (PrEP) for HIV prevention among sub-Saharan African and other women. In particular, women need formulations they can adhere to given that effectiveness has been found to correlate with adherence. Evidence from family planning shows that contraceptive use, continuation and adherence may be increased by expanding choices. To explore the potential role of choice in women's use of HIV prevention methods, we conducted a secondary analysis of research with female sex workers (FSWs) and men and women in serodiscordant couples (SDCs) in Kenya, and adolescent and young women in South Africa. Our objective here is to present their interest in and preferences for PrEP formulations pills, gel and injectable. Methods In this qualitative study, in Kenya we conducted three focus groups with FSWs, and three with SDCs. In South Africa, we conducted two focus groups with adolescent girls, and two with young women. All focus groups were audio-recorded, transcribed and translated into English as needed. We structurally and thematically coded transcripts using a codebook and QSR NVivo 9.0; generated code reports; and conducted inductive thematic analysis to identify major trends and themes. Results All groups expressed strong interest in PrEP products. In Kenya, FSWs said the products might help them earn more money, because they would feel safer accepting more clients or having sex without condoms for a higher price. SDCs said the products might replace condoms and reanimate couples sex lives. Most sex workers and SDCs preferred an injectable because it would last longer, required little intervention and was private. In South Africa, adolescent girls believed it would be possible to obtain the products more privately than condoms. Young women were excited about PrEP but concerned about interactions with alcohol and drug use, which often precede sex. Adolescents did not prefer a particular formulation but noted benefits and limitations of each; young women's preferences also varied. Conclusions The circumstances and preferences of sub-Saharan African women are likely to vary within and across groups and to change over time, highlighting the importance of choice in HIV prevention methods. PMID:25224616

Mack, Natasha; Evens, Emily M; Tolley, Elizabeth E; Brelsford, Kate; Mackenzie, Caroline; Milford, Cecilia; Smit, Jennifer A; Kimani, Joshua

2014-01-01

188

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

189

Numerical Modeling of Climatic Change from the Terminus Record of Lewis Glacier, Mount Kenya  

Microsoft Academic Search

Over the last 100 years, the glaciers and lakes of East Africa have undergone dramatic change in response to climatic forcing. However, the available conventional meterological series have not proven sufficient to explain these environmental events. The secular climatic change at Lewis Glacier, Mount Kenya (0(DEGREES)9'S, 37(DEGREES)19'E), is reconstructed from its terminus record documented since 1893. The short-time-step numerical model

Phillip Donald Kruss

1981-01-01

190

Managing the natural capital of papyrus within riparian zones of Lake Victoria, Kenya  

Microsoft Academic Search

The harvesting of natural products such as papyrus (Cyperus papyrus L.), whether for subsistence value or for the production of commodities intended for sale at local markets, contributes to\\u000a the well-being of riparian peoples around Lake Victoria, Kenya. Serious losses of papyrus wetlands across East Africa have\\u000a been reported, most of which are attributed to increasing anthropogenic stressors. Recent studies

E. H. J. Morrison; C. Upton; K. Odhiambo-Koyooh; D. M. Harper

191

Ocular rhinosporidiosis mimicking conjunctival squamous papilloma in Kenya a case report  

PubMed Central

Background Ocular rhinosporidiosis is a chronic granulomatous infection caused by a newly classified organism that is neither a fungus nor bacterium. It often presents as a benign conjunctival tumour but may mimic other ocular conditions. It is most often described in India. In Africa cases have been reported from South Africa, Kenya, Tanzania, Malawi, Uganda, Congo and Ivory Coast. Case presentation A 54year old man was seen in Kenya with a lesion that resembled a conjunctival papilloma. We report resemblance to conjunctival papilloma and the result of vital staining with 0.05% Toluidine Blue. Conclusion Ocular rhinosporidiosis occurs in East Africa. It may resemble conjunctival squamous papilloma. Vital staining with 0.05% Toluidine blue dye did not distinguish the two lesions well. PMID:24708655

2014-01-01

192

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. PMID:18074022

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

2007-01-01

193

Iwo Eleru's place among Late Pleistocene and Early Holocene populations of North and East Africa.  

PubMed

The Iwo Eleru site in Nigeria preserves the only terminal Pleistocene fossil from tropical West Africa. The peoples of this region contributed to significant population movements throughout the continent during the Holocene. As such, characterizing the phenotype of Late Pleistocene West African populations is critical for disentangling the evolutionary signatures of a highly complex African population history and structure. Previous research approached the calvaria's morphology from a paleoanthropological perspective, noting its mosaic of archaic and modern neurocranial features and distinctiveness from Pleistocene fossil taxa and contemporary modern human samples. In this paper, I compare Iwo Eleru with contemporary Late Pleistocene Africans and also consider the specimen's affinities with Holocene populations of the central and western Sahara, Nile Valley, and East Africa. Craniometric data were recorded for 22 neurocranial dimensions and subjected to principal components analysis and Mahalanobis distance estimation. Multidimensional scaling of distances indicated that Iwo Eleru fell outside the observed range of variation of other terminal Pleistocene supra-equatorial African populations, confirming previous results that documented its divergence from Neanderthals, Upper Paleolithic Europeans, and modern Africans. The calvaria was also distinct from Holocene Saharan, Nile Valley, and East African populations, which suggests limited West African input into the Sahara during the African Humid Period. Results presented here bolster previous research that suggested Iwo Eleru's anatomy reflected either admixture with archaic humans or the long-term survival of populations with more archaic neurocranial anatomy until the end of the Pleistocene. PMID:25065342

Stojanowski, Christopher M

2014-10-01

194

A proposed drainage evolution model for Central AfricaDid 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

195

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

196

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

197

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

NASA Astrophysics Data System (ADS)

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 the Regional Atmospheric Modeling System (RAMS) to compare GHG effects and LCLUC effects on agricultural yield in East Africa. The simulated decadal changes in climate are used to assess changes in agricultural yield as projected by the CERES-Maize model, which takes into consideration time series of air temperature, precipitation, and solar radiation. The results show that: 1) GHG-influenced yields and LCLUC-influenced yields are highly heterogeneous and not generalizable for the region, and 2) LCLUC effects can be either counteract or exacerbate GHG influences, with the greatest impacts occurring in highly populated areas. Spatial variability in impacts on yield among agriculturally important sub-regions can be masked in coarse-scale studies, effectively leading to under-identification of areas with negative impacts on food production. For an accurate assessment of food production, regional and local characteristics of GHG impacts must be considered along with LCLUC influences.

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

2008-12-01

198

The habitat use and selection of African elephants (Loxodonta africana) in a land use landscape in Kenya, Africa  

E-print Network

The habitat use and selection of African elephants (Loxodonta africana) in a land use landscape) to examine how land use and cover types affect the distribution of African elephants in Kenya (2) to determine what land use cover types support larger densities of elephants as a very general indicate

Hansen, Andrew J.

199

The impact of rapid population growth, expanding urbanisation, and other factors on development in sub-Saharan Africa: the contrasting responses of Tanzania and Kenya.  

PubMed

This article analyzes the impact of the twin factors of rapid population growth and expanding urbanization on social and economic development in sub-Saharan Africa and compares policies that have been developed in Tanzania and Kenya in response to these factors. The principal consequences of overpopulation and overurbanization have been economic stagnation and physical and cultural malaise in urban population centers. Between 1960-80, per capita incomes in 19 countries of sub-Saharan Africa grew by less than 1%/year and 15 countries recorded a negative rate of growth in per capita income during the 1970s. Urban populations have increased at at overall rate of 6%/year as sub-Saharan Africans have migrated to cities in search of employment. Few national governments in the region have formulated longterm strategies to deal effectively with this double-faceted development constraint or have integrated new urban populations into the national economy. tanzania's development strategy is focused on the goals of socialism, rural development, and self-reliance. Urban development has remained a residual item in Tanzania's national development process, despite the fact that the urban population increased from 5.7% of the total population in 1967 to 12.7% in 1978 and is projected to comprise 24.7% by the year 2000. In contrast, Kenya, whose proportion of urban population increased from 9% to 15% between 1962 and 1979, has pursued an urban-focused development strategy. The strong urban-rural linkages of the economy have focused migration to the secondary towns. The national development plan includes urban spatial, employment, and investment policies. Although this plan constitutes a good basis for future planning, the magnitude of the urban problem is beyond the capabilities of the central government and requires the development of local capabilities. PMID:12341833

Huth, M J

1984-01-01

200

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

201

Prey spectra of two swarm-raiding army ant species in East Africa  

E-print Network

. Kinuthia3 1 Institute of Biology, Neurobiology, Free University Berlin, K¨onigin-Luise-Strasse, Berlin, Nairobi, Kenya Keywords Dorylus molestus; Dorylus wilverthi; earthworms; Kibale; montane forest; Mount Kenya; polyphagy; predation. Correspondence Caspar Sch¨oning, Department of Population Biology

Menzel, Randolf - Institut für Biologie

202

18/03/2010 11:46IRIN Global | GLOBAL: Is humanitarianism genetic? | Asia East Africa ...Zambia Zimbabwe | In Brief Health & Nutrition Aid Policy | News Item Page 1 of 2http://www.irinnews.org/Report.aspx?ReportId=88437  

E-print Network

18/03/2010 11:46IRIN Global | GLOBAL: Is humanitarianism genetic? | Asia East Africa ...Zambia: Is humanitarianism genetic? | Asia East Africa ...Zambia Zimbabwe | In Brief Health & Nutrition Aid Policy | News

West, Stuart

203

High-Throughput High-Resolution Class I HLA Genotyping in East Africa  

PubMed Central

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

204

Thrust -wrench interference tectonics in the Gulf of Cadiz (Africa -Iberia plate boundary in the North-East Atlantic): insights from  

E-print Network

Thrust - wrench interference tectonics in the Gulf of Cadiz (Africa - Iberia plate boundary to a segment of the Africa- Eurasia plate boundary previously described as tectonically diffuse (e.g. Sartori key segment of the Africa-Iberia plate boundary (North- East Atlantic ocean), three main different

Paris-Sud XI, Université de

205

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 Programs 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

206

CORPORATE GOVERNANCE, OWNERSHIP STRUCTURE AND BANK PERFORMANCE: EVIDENCE FROM THE MIDDLE EAST AND NORTH AFRICA (MENA)1  

Microsoft Academic Search

We study the relationship between ownership structure and performance for a sample of 89 commercial, investment, specialized, and Islamic banks in the Middle East and North Africa (MENA) region for the period 1998-2003.) Our results for commercial banks show that the performance of banks is weakened with board\\/management separation and concentrated ownership, and enhanced with government ownership. I. Introduction The

Sebouh Aintablian; Wajih Al Boustany

207

Languages of the Middle East and North Africa. A Survey of Materials for the Study of the Uncommonly Taught Languages.  

ERIC Educational Resources Information Center

This is an annotated bibliography of basic tools of access for the study of the uncommonly taught languages of the Middle East and North Africa. It is one of eight fascicles which constitute a revision of "A Provisional Survey of Materials for the Study of the Neglected Languages" (CAL 1969). The emphasis is on materials for the adult learner

Johnson, Dora E.; And Others

208

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

209

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

210

Contrasting long-term records of biomass burning in wet and dry savannas of equatorial East Africa  

E-print Network

Contrasting long-term records of biomass burning in wet and dry savannas of equatorial East Africa savanna ecosystems through impacting both the amount and flammability of plant biomass, and consequently on the fire regimes of wet and dry savannas. We reconstructed the long-term dynamics of biomass burning

Bern, Universität

211

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

212

A Human Economy: A "Third Way" for the Future of Young People in the Middle East and North Africa  

ERIC Educational Resources Information Center

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

Zaalouk, Malak

2014-01-01

213

Age and growth determination of the white shark, Carcharodon carcharias, from the east coast of South Africa  

Microsoft Academic Search

The white shark, Carcharodon carcharias, is found worldwide in cold and temperate coastal and shelf waters (Compagno, 1984). As a large, uncommon apex predator, it has received considerable atten- tion from scientists over the past few years. Because of its great re- sale value, compared with most Abstract.-Ages of white sharks, Carcharodon carcharias, from the east coast of South Africa

Sabine P. Wintner; Geremy Cliff

214

The East Africa Oligocene intertrappean beds: Regional distribution, depositional environments and Afro/Arabian mammal dispersals  

NASA Astrophysics Data System (ADS)

The extensive outpouring of the Oligocene Trap basalts over eastern Africa and western Arabia was interrupted by a period of quiescence marked by the deposition of terrestrial sediments. These so-called intertrappean beds are often lignitiferous and yield recurrent floras and faunas, sometimes represented by endemic mammals. We intended to highlight the peculiar features of these sedimentary intercalations using a large-scale approach including eastern Africa and the western Arabian peninsula. Starting from a new mapping in the Eritrean highland, the intertrappean beds resulted a continuous level that was a few tens of meters thick and traceable for some tens of kilometers. They consist of fluvial red, green and gray mudstones and siltstones with subordinate channelized pebbly sandstones, and lignite seams. Two new 40Ar-39Ar datings constraint the age of the intertrappean beds between 29.0 Ma and 23.6 Ma. The outcrops near Mendefera have yielded the remains of two proboscidean families, the Deinotheriidae and the Gomphoteriidae. The morphological grade of the two Mendefera proboscideans would suggest a more derived stage than that of representatives of the same families from other Oligocene African sites (e.g., Chilga, Ethiopia). An Oligocene age could be inferred for them. The occurrence of the genus Prodeinotherium at Mai Gobro possibly represents the first occurrence of this taxon, while the Gomphotheirum sp. might represent the oldest occurrence of this taxon in Africa before its dispersal towards Asia and Europe. Proboscideans have also been found in the lowland intertrappean beds of Dogali near Massawa. These sediments were contiguous with the Eritrean highland intertrappean beds during the Oligocene, but are now tectonically displaced from them by two thousand meters of vertical topographical distance. Dogali is also known for the occurrence of possible Deinotheriidae remains and the primitive elephantoid Eritreum. Entering the Ethiopian highland, an inspection of the Agere Selam (Mekele) intertrappean beds revealed the occurrence of lacustrine limestones and diatomites, which were contrastingly quite subordinate with respect to the fine clastic sediments found in the nearby Amba Alaji area. Further south, the intertrappean section in the Jema valley (100 km north of Addis Ababa and close to the Blue Nile gorge) is 120 m thick with predominant clastic sediments and a few diatomites at the top. Literature information from 35 additional sites, including northern Kenya, Yemen, Sudan and Saudi Arabia sections, confirms the fluvial and lacustrine depositional environment of the intertrappean beds, underlines the interest in their mammal fauna (Chilga, Losodok), and reports exploitable coal seams for some of them. As for the vegetal landscape in which the intertrappean beds were deposited, pollen and plant analysis results indicative of a tropical wet forest, similar to that of present-day western Africa. Another common feature of the intertrappean beds is their relatively limited thickness, averaging a few tens of meters, but reaching a few hundred meters in graben-related basins, such as Delbi Moye in southern Ethiopia. In most cases only thin, lens-shaped successions were deposited above the hummocky topography of their volcanic substratum, commonly unaffected by significant faulting. An average duration of the intertrappean beds is from one to three million years. This time interval is commonly matched by a few tens (or more rarely, hundreds) of meters of sediments left over after erosive episodes or depositional starvation. As to the lateral continuity of the intertrappean beds, the present-day outcrops show large differences: from some tens of kilometers in the Mendefera area, to a few tens of kilometres in the Jema valley, and to a few hundreds meters in the Agere Selam (Mekele) area. Even if it is difficult to quantify the original size of the sedimentation areas, it nevertheless proves that the intertrappean basins exceed thousands of square kilometers in only a single case (Mendefera), but were quite restricte

Abbate, Ernesto; Bruni, Piero; Ferretti, Marco Peter; Delmer, Cyrille; Laurenzi, Marinella Ada; Hagos, Miruts; Bedri, Omar; Rook, Lorenzo; Sagri, Mario; Libsekal, Yosief

2014-11-01

215

Diet of Paranthropus boisei in the early Pleistocene of East Africa  

PubMed Central

The East African hominin Paranthropus boisei was characterized by a suite of craniodental features that have been widely interpreted as adaptations to a diet that consisted of hard objects that required powerful peak masticatory loads. These morphological adaptations represent the culmination of an evolutionary trend that began in earlier taxa such as Australopithecus afarensis, and presumably facilitated utilization of open habitats in the Plio-Pleistocene. Here, we use stable isotopes to show that P. boisei had a diet that was dominated by C4 biomass such as grasses or sedges. Its diet included more C4 biomass than any other hominin studied to date, including its congener Paranthropus robustus from South Africa. These results, coupled with recent evidence from dental microwear, may indicate that the remarkable craniodental morphology of this taxon represents an adaptation for processing large quantities of low-quality vegetation rather than hard objects. PMID:21536914

Cerling, Thure E.; Mbua, Emma; Kirera, Francis M.; Manthi, Fredrick Kyalo; Grine, Frederick E.; Leakey, Meave G.; Sponheimer, Matt; Uno, Kevin T.

2011-01-01

216

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

217

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. PMID:21509269

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

2009-01-01

218

Pathways to healing: curative travel among Muslims and non-Muslims in eastern East Africa.  

PubMed

Two areas of therapeutic provision in eastern East Africa are contrasted: a coastal stretch inhabited mainly by Muslims, and a largely non-Muslim hinterland, each with its own healers, medicines, and customary ethic. Spread over both areas are providers of biomedicine associated originally, and to some extent today, with Christianity. Whether or not they also attend biomedical sites, Muslims seek healers in the coastal stretch and non-Muslims usually in the hinterland, each following ethico-religious preferences. However, because people move through the two areas and compare treatments, individuals' journeys can change direction, with non-Muslims sometimes seeking Muslim healers and either of these groups choosing the more dispersed biomedical outlets. The notion of 'pathways' to health thus combines set journeys to areas known for particular healers and a distinctive ethic, with possible detours to alternative sources of therapy, including biomedicine not regarded as governed by the same ethic. PMID:24383750

Parkin, David

2014-01-01

219

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

220

Upper mantle attenuation structure beneath East Africa from relative t* measurements  

NASA Astrophysics Data System (ADS)

We are studying the attenuation structure of the upper mantle beneath east Africa using body waves recorded by a PASSCAL array that was deployed in Tanzania between 1994-1995. The array runs along two profiles (EW and NE-SW) that traverse the Tanzania craton and the surrounding rifted mobile belts. Studying this region may provide important clues on the initiation of Cenozoic rifting in east Africa and hence, give us insights into the tectonic and geodynamic processes that occur during the initial stages of rift development. The same dataset has been used to obtain tomographic velocity models, so we can compare the velocity structure to the attenuation structure. We determined the P wave spectral amplitude ratios of data from the same earthquake recorded at different stations (thereby eliminating the source effect), and computed relative t* (path integrated attenuation) from the slopes of these ratios. We then used a least-squares inversion to determine the t* at each station relative to the average t* of the array. We applied the same procedure to determine relative t* for S waves from the transverse components of the data (i.e., SH only). To simplify the problem, we selected events that have azimuths along the two profiles, and we have initially focused on events along the EW profile. On comparing the estimates of t* to the residual travel times estimated by Ritsema et. al., (1998), we observe that the t* values and residual travel times are not always correlated. Also, the observed t* values from P wave data are anti-correlated to the observed S wave data for stations within the craton. We are planning to compute forward models in order to isolate elastic from anelastic effects on our t* measurements, and to place constraints on upper mantle Q values.

Nyblade, A. A.; Venkataraman, A.; Ritsema, J.

2003-12-01

221

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 3C 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 ~5C, 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 Damst, J. S.

2011-12-01

222

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

223

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

NASA Astrophysics Data System (ADS)

During an El Nio, 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

224

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

225

Application of the QUILF thermobarometer to the peralkaline trachytes and pantellerites of the Eburru volcanic complex, East African Rift, Kenya  

Microsoft Academic Search

The Quaternary Eburru volcanic complex in the south-central Kenya Rift consists of pantelleritic trachytes and pantellerites. The phenocryst assemblage in the trachytes is sanidine+fayalite+ferrohedenbergite+aenigmatitequartzilmenitemagnetitepyrrhotitepyrite. In the pantellerites, the assemblage is sanidine+quartz+ferrohedenbergite+fayalite+aenigmatite+ferrorichterite+pyrrhotiteapatite, although fayalite, ferrohedenbergite and ilmenite are absent from more evolved rocks (e.g. with SiO2>71%). QUILF temperature calculations for the trachytes range from 709 to 793C and for the pantellerites

Minghua Ren; Peter A. Omenda; Elizabeth Y. Anthony; John C. White; Ray Macdonald; D. K. Bailey

2006-01-01

226

Spatially explicit, individual-based modelling of pastoralists' mobility in the rangelands of east Africa  

E-print Network

An agent based-model of mobility of pastoralists was developed and applied to the semi-arid rangeland region extending from southern Ethiopia to northern Kenya. This model was used to investigate temporal adaptation of pastoralists to the spatial...

MacOpiyo, Laban Adero

2005-11-01

227

Water Resources, Adaptation to Climate Change and Social Action in East Africa  

E-print Network

Mt Kenya Mt ElgonMt Elgon Indian O cean Rufiji Tan a Rufiji Tan a Lake Albert Lake Albert Lake Turkana Lake Turkana Lake Victoria Lake Victoria Lake Tanganyika Lake Tanganyika Lake Rukwa Lake Rukwa BURUNDI MALAWI

Richner, Heinz

228

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 ~1.5C 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 ~18.4C 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 ~3C over the remainder of the record.

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

2010-12-01

229

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 (~3S). 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 ~5C 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

230

Lake Challa (Mt. Kilimanjaro) sediments as recorder of present and past seasonality in equatorial East Africa  

NASA Astrophysics Data System (ADS)

In discussions on the impact of global warming on moisture balance and human water resources, natural archives of past hydrological variability in tropical regions are attracting increasing attention. The EuroCLIMATE project CHALLACEA studies the sediment archive of Lake Challa, a 4.5 km and ~94 m deep crater lake located on the lower eastern slope of Mt. Kilimanjaro with the aim to produce a continuous, high-resolution and multi-proxy reconstruction of past temperature and moisture-balance variability in equatorial East Africa over the past 25,000 years. Lake Challa is a freshwater lake with a water budget controlled mostly by sub-surface in- and outflow and lake-surface evaporation. Accordingly, microscopic thin-section investigation of sediment composition reveals an overall dominance of autochthonous components (diatom frustules, calcite, and organic matter). First results from an ongoing sediment trap study point to distinct seasonality in sediment input: calcite and organic matter accumulate during the warm southern hemisphere summer months (November - March), whereas the principal diatom blooms occur during the cool and windy period between June and October. Here we present the results of physical and chemical investigations of the lake water column between September 1999 and November 2007, which document the concomitant seasonal changes in lake mixing/stratification and related element cycling. High-resolution ?XRF profiles of these elements in the laminated sediments of Lake Challa thus also show marked seasonal cycles, as well as longer-term variability. In particular, variability in the Mn/Fe ratio along the top 15 cm of the sediment record is interpreted to reflect changes in lake stratification during the last ~100 years. This proxy record is evaluated in comparison with records of historical weather variability in East Africa, and of potentially influencing parameters such as the El Nio Southern Oscillation and the Indian Ocean Dipole. Eventually these exercises may contribute to high-resolution reconstruction of tropical East African climate variability over the last 25,000 years.

Kristen, I.; Wolff, C.; Schettler, G.; Dulski, P.; Naumann, R.; Haug, G. H.; Blaauw, M.; Verschuren, D.

2008-12-01

231

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

232

Intrt biochronologique des Kubanochoerinae (Mammalia, Suidae) et tude de nouveaux restes de Megalochoerus khinzikebirus et Libycochoerus massai du KenyaThe biochronological importance of Kubanochoerine (Mammalia, Suidae), together with a description of new material of Megalochoerus khinzikebirus and Libycochoerus massai from Kenya  

NASA Astrophysics Data System (ADS)

Kubanochoerine suids underwent such rapid increase in size from Early to Middle Miocene times that they can be used for biochronology. Megalochoerus khinzikebirus, a gigantic suid occurs at Gebel Zelten, Libya, and at two sites in Kenya dated about 15 Ma. Even larger suids of the same lineage ( Megalochoerus homungous) are known from younger deposits in Kenya, Pakistan, Libya and Turkey. The smaller species, Megalochoerus marymuunguae occurs in earlier strata in Kenya (ca 17.2 Ma) and it is, in its turn, larger than older species such as Libycochoerus jeanneli (17-17.8 Ma), Kenyasus rusingensis (17.8 Ma) and Nguruwe kijivium (ca 20 Ma) from East Africa. A record of Libycochoerus massai from the Tugen hills, Kenya (ca 15.5 Ma) provides further evidence in support of the usefulness of this lineage for geochronology.

Pickford, Martin

2001-02-01

233

Contraceptive Use in Women Enrolled into Preventive HIV Vaccine Trials: Experience from a Phase I/II Trial in East Africa  

PubMed Central

Background HIV vaccine trials generally require that pregnant women are excluded from participation, and contraceptive methods must be used to prevent pregnancy during the trial. However, access to quality services and misconceptions associated with contraceptive methods may impact on their effective use in developing countries. We describe the pattern of contraceptive use in a multi-site phase I/IIa HIV Vaccine trial in East Africa (Uganda, Kenya and Tanzania) and factors that may have influenced their use during the trial. Methods Pregnancy prevention counseling was provided to female participants during informed consent process and at each study visit. Participants' methods of contraception used were documented. Methods of contraceptives were provided on site. Pregnancy testing was done at designated visits during the trial. Obstacles to contraceptive use were identified and addressed at each visit. Results Overall, 103 (31.8%) of a total of 324 enrolled volunteers were females. Female participants were generally young with a mean age of 29(7.2), married (49.5%) and had less than high school education (62.1%). Hormonal contraceptives were the most common method of contraception (58.3%) followed by condom use (22.3%). The distribution of methods of contraception among the three sites was similar except for more condom use and less abstinence in Uganda. The majority of women (85.4%) reported to contraceptive use prior to screening. The reasons for not using contraception included access to quality services, insufficient knowledge of certain methods, and misconceptions. Conclusion Although hormonal contraceptives were frequently used by females participating in the vaccine trial, misconceptions and their incorrect use might have led to inconsistent use resulting in undesired pregnancies. The study underscores the need for an integrated approach to pregnancy prevention counseling during HIV vaccine trials. Trial Registration ClinicalTrials.gov NCT00123968 PMID:19360102

Kibuuka, Hannah; Guwatudde, David; Kimutai, Robert; Maganga, Lucas; Maboko, Leonard; Watyema, Cecilia; Sawe, Fredrick; Shaffer, Douglas; Matsiko, Dickson; Millard, Monica; Michael, Nelson; Wabwire-Mangen, Fred; Robb, Merlin

2009-01-01

234

Prevalence and comparison of Streptococcus infantarius subsp. infantarius and Streptococcus gallolyticus subsp. macedonicus in raw and fermented dairy products from East and West Africa.  

PubMed

Streptococcus infantarius subsp. infantarius (Sii) and Streptococcus gallolyticus subsp. macedonicus are members of the Streptococcus bovis/Streptococcus equinus complex (SBSEC) associated with human infections. SBSEC-related endocarditis was furthermore associated with rural residency in Southern Europe. SBSEC members are increasingly isolated as predominant species from fermented dairy products in Europe, Asia and Africa. African variants of Sii displayed dairy adaptations to lactose metabolism paralleling those of Streptococcus thermophilus including genome decay. In this study, the aim was to assess the prevalence of Sii and possibly other SBSEC members in dairy products of East and West Africa in order to identify their habitat, estimate their importance in dairy fermentation processes and determine geographic areas affected by this potential health risk. Presumptive SBSEC members were isolated on semi-selective M17 and SM agar media. Subsequent genotypic identification of isolates was based on rep-PCR fingerprinting and SBSEC-specific16S rRNA gene PCR assay. Detailed identification was achieved through application of novel primers enhancing the binding stringency in partial groES/groEL gene amplification and subsequent DNA sequencing. The presence of S. thermophilus-like lacS and lacZ genes in the SBSEC isolates was determined to elucidate the prevalence of this dairy adaptation. Isolates (n = 754) were obtained from 72 raw and 95 fermented milk samples from Cte d'Ivoire and Kenya on semi-selective agar media. Colonies of Sii were not detected from raw milk despite high microbial titers of approximately 10(6)CFU/mL on M17 agar medium. However, after spontaneous milk fermentation Sii was genotypically identified in 94.1% of Kenyan samples and 60.8% of Kenyan isolates. Sii prevalence in Cte d'Ivoire displayed seasonal variations in samples from 32.3% (June) to 40.0% (Dec/Jan) and isolates from 20.5% (June) to 27.7% (Dec/Jan) present at titers of 10(6)-10(8)CFU/mL. lacS and lacZ genes were detected in all Kenyan and 25.8% (June) to 65.4% (Dec/Jan) of Ivorian Sii isolates. Regional differences in prevalence of Sii and dairy adaptations were observed, but no clear effect of dairy animal, fermentation procedure and climate was revealed. Conclusively, the high prevalence of Sii in Kenya, Cte d'Ivoire in addition to Somalia, Sudan and Mali strongly indicates a pivotal role of Sii in traditional African dairy fermentations potentially paralleling that of typical western dairy species S. thermophilus. Putative health risks associated with the consumption of high amounts of live Sii and potential different degrees of evolutionary adaptation or ecological colonization require further epidemiologic and genomic investigations, particularly in Africa. PMID:24131584

Jans, Christoph; Kaindi, Dasel Wambua Mulwa; Bck, Dsire; Njage, Patrick Murigu Kamau; Kouam-Sina, Sylvie Mireille; Bonfoh, Bassirou; Lacroix, Christophe; Meile, Leo

2013-10-15

235

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

236

Effectiveness trial of community-based I Choose Life-Africa human immunodeficiency virus prevention program in Kenya.  

PubMed

We measured the effectiveness of a human immunodeficiency virus (HIV) prevention program developed in Kenya and carried out among university students. A total of 182 student volunteers were randomized into an intervention group who received a 32-hour training course as HIV prevention peer educators and a control group who received no training. Repeated measures assessed HIV-related attitudes, intentions, knowledge, and behaviors four times over six months. Data were analyzed by using linear mixed models to compare the rate of change on 13 dependent variables that examined sexual risk behavior. Based on multi-level models, the slope coefficients for four variables showed reliable change in the hoped for direction: abstinence from oral, vaginal, or anal sex in the last two months, condom attitudes, HIV testing, and refusal skill. The intervention demonstrated evidence of non-zero slope coefficients in the hoped for direction on 12 of 13 dependent variables. The intervention reduced sexual risk behavior. PMID:24957544

Adam, Mary B

2014-09-01

237

The origin and age of haplochromine fishes in Lake Victoria, east Africa.  

PubMed Central

According to a widely held view, the more than 300 species of haplochromine cichlid fishes in Lake Victoria (LV), East Africa, originated from a single founder species in less than 12,000 years. This view, however, does not follow from the published geological and molecular evidence. The former does indeed suggest that the LV basin dried out less than 15,000 years ago, but it does not provide any information about the species that re-colonized the new lake or that remained in the rivers draining the area. The molecular evidence is inconclusive with respect to the origin of the LV haplochromines because cichlids from critical regions around LV were not adequately sampled; and as far as the age of the LV haplochromines is concerned, it in fact led to an estimate of 250,000-750,000 years old. In the present study, mitochondrial DNA (control region) variation was determined by heteroduplex and sequencing analyses of more than 670 specimens collected at widely distributed East African riverine and lacustrine localities. The analyses revealed the existence of seven haplogroups (I-VII) distinguishable by characteristic substitutions. All endemic LV samples tested fell into one of these haplogroups (V) which, however, was also found to be present at various other localities, both riverine and lacustrine, outside LV. Within this haplogroup, four subgroups (VA through VD) could be distinguished, two of which (VB and VC) were represented in LV and at other localities. The great majority of the LV haplochromine species could be classified as belonging to the VC subgroup, which was found only in LV and in the rivers draining into it. Hence, while the endemic haplochromine species of LV could not have originated from a single founding population, the lake does harbour a large species flock which probably arose in situ. PMID:10874756

Nagl, S; Tichy, H; Mayer, W E; Takezaki, N; Takahata, N; Klein, J

2000-01-01

238

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

239

Management of psoriasis in Africa and the Middle East: a review of current opinion, practice and opportunities for improvement.  

PubMed

Psoriasis is a common, chronic, systemic, inflammatory disease of the skin that is often associated with inflammatory musculoskeletal disease. Psoriasis impacts on affected individuals and on society at many levels, being associated with considerable economic burden and impaired quality of life. This article aims to provide dermatologists and their allied healthcare professionals, particularly those practicing in Africa and the Middle East, with a review of the current understanding of psoriasis, its treatment and impact, as a backdrop for further discussion of the management of psoriasis in these regions. Insight into the real-life, day-to-day challenges and unmet needs currently facing dermatologists in Africa and the Middle East is provided by the authors, most of whom are experienced dermatologists practicing in this region. PMID:22117959

Abdulghani, M; Al Sheik, A; Alkhawajah, M; Ammoury, A; Behrens, F; Benchikhi, H; Benkaidali, I; Doss, N; El Gendy, A; Mokhtar, I; Odendaal, D; Raboobee, N; Thai, D; Weiss, R; Whitaker, D

2011-01-01

240

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

Microsoft Academic Search

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 87Sr\\/86Sr ratio, 143Nd\\/144Nd is lower in most phonolites than in the nephelinites and carbonatites. Interaction between nephelinitic magma and lower-crustal granulites can account for

Keith Bell; Tony Peterson

1991-01-01

241

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 Lrdal

2000-01-01

242

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. PMID:15836787

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

2005-01-01

243

Evaluation ofthe Middle East and North Africa Land Data Assimilation System  

NASA Technical Reports Server (NTRS)

The Middle East and North Africa (MENA) region 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 hydro climatic 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 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. The Land Data Assimilation System for the MENA region (MENA LDAS) has been developed to provide regional, gridded fields of hydrological states and fluxes relevant for water resources assessments. As an extension of the Global Land Data Assimilation System (GLDAS), the MENA LDAS was designed 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.

Bolten, John D.; Rodell, Matthew; Zaitchik, Benjamin; Ozdogan, Mutlu; Anderson, Martha; Bergaoui, Karim B.; Khalaf, Adla J.; McDonnell, Rachael A.

2012-01-01

244

Regional Climate Response to Volcanic Radiative Forcing in Middle East and North Africa  

NASA Astrophysics Data System (ADS)

We have tested the regional climate sensitivity in the Middle East and North Africa (MENA) to radiation perturbations caused by the large explosive equatorial volcanic eruptions of the second part of 20th century, El Chichon and Pinatubo occurred, respectively, in 1982 and 1991. The observations and reanalysis data show that the surface volcanic cooling in the MENA region is two-three times larger than the global mean response to volcanic forcing. The Red Sea surface temperature appears to be also very sensitive to the external radiative impact. E.g., the sea surface cooling, associated with the 1991 Pinatubo eruption, caused deep water mixing and coral bleaching for a few years. To better quantify these effects we use the Geophysical Fluid Dynamics Laboratory global High Resolution Atmospheric Model (HIRAM) to conduct simulations of both the El Chichon and Pinatubo impacts with the effectively 25-km grid spacing. We find that the circulation changes associated with the positive phase of the arctic oscillation amplified the winter temperature anomalies in 1982-1984 and 1991-1993. The dynamic response to volcanic cooling also is characterized by the southward shift of the inter-tropical convergence zone in summer and associated impact on the precipitation patterns. Thus, these results suggest that the climate regime in the MENA region is highly sensitive to external forcing. This is important for better understanding of the climate variability and change in this region.

Stenchikov, G.; Dogar, M.

2012-04-01

245

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? = 0.420.63, 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 = 0.170.39). 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. PMID:23956475

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

2013-01-01

246

Thermophilic Sulfate Reduction in Hydrothermal Sediment of Lake Tanganyika, East Africa  

PubMed Central

In environments with temperatures above 60C, thermophilic prokaryotes are the only metabolically active life-forms. By using the 35SO42- tracer technique, we studied the activity of sulfate-reducing microorganisms (SRM) in hot sediment from a hydrothermal vent site in the northern part of freshwater Lake Tanganyika (East Africa). Incubation of slurry samples at 8 to 90C demonstrated meso- and thermophilic sulfate reduction with optimum temperatures of 34 to 45C and 56 to 65C, respectively, and with an upper temperature limit of 80C. Sulfate reduction was stimulated at all temperatures by the addition of short-chain fatty acids and benzoate or complex substrates (yeast extract and peptone). A time course experiment showed that linear thermophilic sulfate consumption occurred after a lag phase (12 h) and indicated the presence of a large population of SRM in the hydrothermal sediment. Thermophilic sulfate reduction had a pH optimum of about 7 and was completely inhibited at pH 8.8 to 9.2. SRM could be enriched from hydrothermal chimney and sediment samples at 60 and 75C. In lactate-grown enrichments, sulfide production occurred at up to 70 and 75C, with optima at 63 and 71C, respectively. Several sporulating thermophilic enrichments were morphologically similar to Desulfotomaculum spp. Dissimilatory sulfate reduction in the studied hydrothermal area of Lake Tanganyika apparently has an upper temperature limit of 80C. PMID:16349249

Elsgaard, Lars; Prieur, Daniel; Mukwaya, Gashagaza M.; Jrgensen, Bo B.

1994-01-01

247

Aerial applications of insecticides for tsetse fly control in East Africa  

PubMed Central

Since 1948, research has progressed in East Africa on the control of tsetse flies by aeria, applications of insecticides. Initial experiments proved that residual spray treatments were ineffective while repeated applications of coarse aerosols gave promising fly mortalities. In recent years, with the development of more toxic insecticides used in conjunction with improved thermal exhaust equipment and modified rotary atomizers, sprays with fine aerosol characteristics have been produced at considerably reduced cost. Aerial applications of aerosols are confined to early morning and late afternoon when weather conditions are stable, but large areas can be treated during these short intervals, and the technique is efficient and economical. Control of tsetse flies has been good; where complete isolation of an area has been possible, eradication has been achieved. It would be economically worth while to assess the possibility of increasing spray swath widths, and also to continue with research into the biological effectiveness of pyrethrum, primarily because of its absolute safety in use. There is a need for a simple method for the determination of tsetse fly populations in woodland and savanna habitats. Finally, it is recommended that the results of research to date should be brought more forcefully to the attention of government bodies and commercial airspray operators so that the techniques be more fully exploited. PMID:5308701

Lee, C. W.

1969-01-01

248

Cost of Illness Due to Typhoid Fever in Pemba, Zanzibar, East Africa  

PubMed Central

ABSTRACT The aim of this study was to estimate the economic burden of typhoid fever in Pemba, Zanzibar, East Africa. This study was an incidence-based cost-of-illness analysis from a societal perspective. It covered new episodes of blood culture-confirmed typhoid fever in patients presenting at the outpatient or inpatient departments of three district hospitals between May 2010 and December 2010. Cost of illness was the sum of direct costs and costs for productivity loss. Direct costs covered treatment, travel, and meals. Productivity costs were loss of income by patients and caregivers. The analysis included 17 episodes. The mean age of the patients, was 23 years (range=5-65, median=22). Thirty-five percent were inpatients, with a mean of 4.75 days of hospital stay (range=3-7, median=4.50). The mean cost for treatment alone during hospital care was US$ 21.97 at 2010 prices (US$ 1=1,430.50 Tanzanian Shilling?TSH). The average societal cost was US$ 154.47 per typhoid episode. The major expenditure was productivity cost due to lost wages of US$ 128.02 (83%). Our results contribute to the further economic evaluation of typhoid fever vaccination in Zanzibar and other sub-Saharan African countries. PMID:25395900

Piatti, Moritz; Ley, Benedikt; Deen, Jacqueline; Thriemer, Kamala; von Seidlein, Lorenz; Salehjiddawi, Mohammad; Busch, Clara Jana-Lui; Schmied, Wolfgang H.; Ali, Said Mohammed; The Typhoid Economic Study Group (GiDeok Pak, Leon R. Ochiai, Mahesh K. Puri, Na Yoon Chang, Thomas F. Wierzba, and John D. Clemens)

2014-01-01

249

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

250

Cost of illness due to typhoid Fever in pemba, zanzibar, East Africa.  

PubMed

The aim of this study was to estimate the economic burden of typhoid fever in Pemba, Zanzibar, East Africa. This study was an incidence-based cost-of-illness analysis from a societal perspective. It covered new episodes of blood culture-confirmed typhoid fever in patients presenting at the outpatient or inpatient departments of three district hospitals between May 2010 and December 2010. Cost of illness was the sum of direct costs and costs for productivity loss. Direct costs covered treatment, travel, and meals. Productivity costs were loss of income by patients and caregivers. The analysis included 17 episodes. The mean age of the patients, was 23 years (range=5-65, median=22). Thirty-five percent were inpatients, with a mean of 4.75 days of hospital stay (range=3-7, median=4.50). The mean cost for treatment alone during hospital care was US$ 21.97 at 2010 prices (US$ 1=1,430.50 Tanzanian Shilling?TSH). The average societal cost was US$ 154.47 per typhoid episode. The major expenditure was productivity cost due to lost wages of US$ 128.02 (83%). Our results contribute to the further economic evaluation of typhoid fever vaccination in Zanzibar and other sub-Saharan African countries. PMID:25395900

Riewpaiboon, Arthorn; Piatti, Moritz; Ley, Benedikt; Deen, Jacqueline; Thriemer, Kamala; von Seidlein, Lorenz; Salehjiddawi, Mohammad; Busch, Clara Jana-Lui; Schmied, Wolfgang H; Ali, Said Mohammed; The Typhoid Economic Study Group GiDeok Pak Leon R Ochiai Mahesh K Puri Na Yoon Chang Thomas F Wierzba And John D Clemens

2014-09-01

251

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

252

Concentrating solar power in Europe, the Middle East and North Africa: achieving its potential  

NASA Astrophysics Data System (ADS)

Concentrating solar power (CSP) is a commercially available renewable energy technology capable of harnessing the immense solar resource in Southern Europe, the Middle East and North Africa (the MENA region), and elsewhere. This paper summarises the findings of a study by the European Academies Science Advisory Council which has examined the current status and development challenges of CSP, and consequently has evaluated the potential contribution of CSP in Europe and the MENA region to 2050. It identifies the actions that will be required by scientists, engineers, policy makers, politicians, business and investors alike, to enable this vast solar resource to make a major contribution to establishing a sustainable energy system. The study concludes that cost reductions of 50-60% in CSP electricity may reasonably be expected in the next 10-15 years, enabling the technology to be cost competitive with fossil-fired power generation at some point between 2020 and 2030. Incorporation of storage delivers added value in enabling CSP to deliver dispatchable power. Incentive schemes will be needed in Europe and MENA countries to enable this point to be achieved. Such schemes should reflect the true value of electricity to the grid, effectively drive R&D, and ensure transparency of performance and cost data.

Pitz-Paal, R.; Amin, A.; Bettzge, M.; Eames, P.; Fabrizi, F.; Flamant, G.; Garcia Novo, F.; Holmes, J.; Kribus, A.; van der Laan, H.; Lopez, C.; Papagiannakopoulos, P.; Pihl, E.; Smith, P.; Wagner, H.-J.

2012-10-01

253

Bilharziasis survey in British West and East Africa, Nyasaland, and the Rhodesias*  

PubMed Central

The author, in his capacity as a WHO consultant, undertook a survey of bilharziasis in British West and East Africa and Nyasaland during 1950-51. The information thus obtained has been revised and brought up to date and is recorded in the present article together with similar observations on Northern Rhodesia, which was not visited, and on Southern Rhodesia, the author's own country. In Part I, each country is dealt with in turn. The history of the disease and the findings of field surveys are reviewed, and, wherever possible, personal observations have been included. The fact that the information is of a scanty and incomplete nature is an indication that further local studies in all areas are badly needed. In Part II an attempt is made to survey the situation from the point of view of the various aspects of the subjectsmethods of obtaining morbidity data, intensity of infection, effects of the disease on human health, treatment, and the molluscan vectors. PMID:13383363

Blair, Dyson M.

1956-01-01

254

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

255

TeleEducation Initiatives for Sub-Saharan Africa: The Case of the African Virtual University in Kenya  

ERIC Educational Resources Information Center

Sub-Saharan Africa (SSA) lags behind the rest of the world in education. Less than 25 percent of qualified high school graduates in this region will make it to the university level, mainly because most countries within the region have less than three universities. Furthermore, alternatives to universities such as two year colleges and training

Wilkerson, DerKirra; Simmons, Lakisha; Mbarika, Victor; Thomas, Carlos; Mbarika, Irene; Tsuma, Clive; Wade, Tamiara L.

2011-01-01

256

Origin of Lower Cretaceous (`Nubian') sandstones of North-east Africa and Arabia from detrital zircon U-Pb SHRIMP dating  

E-print Network

Origin of Lower Cretaceous (`Nubian') sandstones of North-east Africa and Arabia from detrital Cretaceous sandstones of the type exposed in Israel, deposited over much of North Africa and Arabia as widespread sandstone sheets, typically are mineralogically and texturally mature. Previous petrographic

Dov, Avigad

257

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

PubMed

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. PMID:20534571

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

2010-06-01

258

ZHANG, XUEJIN. Adapting the Weather Research and Forecasting Model for the Simulation of Regional Climate in East Africa. (Under the direction of Dr. Lian Xie).  

E-print Network

. #12;Adapting the Weather Research and Forecasting Model for the Simulation of Regional Climate in EastABSTRACT ZHANG, XUEJIN. Adapting the Weather Research and Forecasting Model for the Simulation of Regional Climate in East Africa. (Under the direction of Dr. Lian Xie). The regional climate model (RCM

Liu, Paul

259

Additional results on palaeomagnetic stratigraphy of the Koobi Fora Formation, east of Lake Turkana (Lake Rudolf), Kenya  

USGS Publications Warehouse

The magnetostratigraphy of the hominid-bearing sediments exposed east of Lake Turkana has been strengthened by new palaeomagnetic results. Ages obtained from several tuffs by the 40Ar/39Ar method suggest an approxmate match between the observed magnetozones and the geomagnetic polarity time scale; however, the palaeomagnetic results are also compatible with a younger chronology suggested by conventional K-Ar dating of the KBS Tuff. ?? 1977 Nature Publishing Group.

Hillhouse, J.W.; Ndombi, J.W.M.; Cox, A.; Brock, A.

1977-01-01

260

Additional results on palaeomagnetic stratigraphy of the Koobi Fora Formation, east of Lake Turkana (Lake Rudolf), Kenya  

Microsoft Academic Search

The magnetostratigraphy of the hominid-bearing sediments exposed east of Lake Turkana has been strengthened by new palaeomagnetic results. Ages obtained from several tuffs by the 40Ar\\/39Ar method suggest an approxmate match between the observed magnetozones and the geomagnetic polarity time scale; however, the palaeomagnetic results are also compatible with a younger chronology suggested by conventional K-Ar dating of the KBS

J. W. Hillhouse

1977-01-01

261

Ash from the Toba supereruption in Lake Malawi shows no volcanic winter in East Africa at 75 ka.  

PubMed

The most explosive volcanic event of the Quaternary was the eruption of Mt. Toba, Sumatra, 75,000 y ago, which produced voluminous ash deposits found across much of the Indian Ocean, Indian Peninsula, and South China Sea. A major climatic downturn observed within the Greenland ice cores has been attributed to the cooling effects of the ash and aerosols ejected during the eruption of the Youngest Toba Tuff (YTT). These events coincided roughly with a hypothesized human genetic bottleneck, when the number of our species in Africa may have been reduced to near extinction. Some have speculated that the demise of early modern humans at that time was due in part to a dramatic climate shift triggered by the supereruption. Others have argued that environmental conditions would not have been so severe to have such an impact on our ancestors, and furthermore, that modern humans may have already expanded beyond Africa by this time. We report an observation of the YTT in Africa, recovered as a cryptotephra layer in Lake Malawi sediments, >7,000 km west of the source volcano. The YTT isochron provides an accurate and precise age estimate for the Lake Malawi paleoclimate record, which revises the chronology of past climatic events in East Africa. The YTT in Lake Malawi is not accompanied by a major change in sediment composition or evidence for substantial temperature change, implying that the eruption did not significantly impact the climate of East Africa and was not the cause of a human genetic bottleneck at that time. PMID:23630269

Lane, Christine S; Chorn, Ben T; Johnson, Thomas C

2013-05-14

262

Ash from the Toba supereruption in Lake Malawi shows no volcanic winter in East Africa at 75 ka  

PubMed Central

The most explosive volcanic event of the Quaternary was the eruption of Mt. Toba, Sumatra, 75,000 y ago, which produced voluminous ash deposits found across much of the Indian Ocean, Indian Peninsula, and South China Sea. A major climatic downturn observed within the Greenland ice cores has been attributed to the cooling effects of the ash and aerosols ejected during the eruption of the Youngest Toba Tuff (YTT). These events coincided roughly with a hypothesized human genetic bottleneck, when the number of our species in Africa may have been reduced to near extinction. Some have speculated that the demise of early modern humans at that time was due in part to a dramatic climate shift triggered by the supereruption. Others have argued that environmental conditions would not have been so severe to have such an impact on our ancestors, and furthermore, that modern humans may have already expanded beyond Africa by this time. We report an observation of the YTT in Africa, recovered as a cryptotephra layer in Lake Malawi sediments, >7,000 km west of the source volcano. The YTT isochron provides an accurate and precise age estimate for the Lake Malawi paleoclimate record, which revises the chronology of past climatic events in East Africa. The YTT in Lake Malawi is not accompanied by a major change in sediment composition or evidence for substantial temperature change, implying that the eruption did not significantly impact the climate of East Africa and was not the cause of a human genetic bottleneck at that time. PMID:23630269

Lane, Christine S.; Chorn, Ben T.; Johnson, Thomas C.

2013-01-01

263

Characterising the progress in HIV/AIDS research in the Middle East and North Africa  

PubMed Central

Objectives The Middle East and North Africa (MENA) region is perceived to have limited HIV data. The objective of this study was to quantitatively characterise the progress in HIV research in this region since the discovery of the epidemic. Methods Four indices were defined and implemented to measure the progress of HIV research using the PubMed, Embase, MENA HIV/AIDS Epidemiology Synthesis Project and US Census Bureau HIV/AIDS Surveillance databases. The four indices provide complementary measures to characterise different aspects of the progress of HIV research. Results A total of 2118, 2352, 683 and 4889 records were identified through the PubMed, the Embase, the Synthesis Project and the HIV Prevalence indices, respectively. The proportion of the total global HIV records that relate to MENA is 1.2%. Overall, the indices show steady progress in the number of new records every year, with an accelerated pace in the last few years. The rate of progress in MENA was also higher than the rate of progress in HIV records globally. There is no evidence so far of stabilisation or a peak in the number of new records year by year. About half of the records were produced after the year 2005. The number of records shows large heterogeneity across countries. Conclusions MENA has witnessed a rapid growth in HIV research over the last decade. However, there are still large gaps in HIV scientific evidence in the region, and the progress is far from being uniform across countries. Ongoing and future research needs to be geared towards academic standard and production of scientific publications. PMID:23596206

Saba, Hanan F; Kouyoumjian, Silva P; Mumtaz, Ghina R; Abu-Raddad, Laith J

2013-01-01

264

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

265

Regional nitrogen budget of the Lake Victoria Basin, East Africa: syntheses, uncertainties and perspectives  

NASA Astrophysics Data System (ADS)

Using the net anthropogenic nitrogen input (NANI) approach we estimated the N budget for the Lake Victoria Basin in East Africa. The NANI of the basin ranged from 887 to 3008 kg N km?2 yr?1 (mean: 1827 kg N km?2 yr?1) for the period 19952000. The net nitrogen release at basin level is due primarily to livestock and human consumption of feed and foods, contributing between 69% and 85%. Atmospheric oxidized N deposition contributed approximately 14% to the NANI of the Lake Victoria Basin, while either synthetic N fertilizer imports or biological N fixations only contributed less than 6% to the regional NANI. Due to the low N imports of feed and food products (<20 kg N km?2 yr?1), nitrogen release to the watershed must be derived from the mining of soil N stocks. The fraction of riverine N export to Lake Victoria accounted for 16%, which is much lower than for watersheds located in Europe and USA (25%). A significant reduction of the uncertainty of our N budget estimate for Lake Victoria Basin would be possible if better data on livestock systems and riverine N export were available. Our study indicates that at present soil N mining is the main source of nitrogen in the Lake Victoria Basin. Thus, sustainable N management requires increasing agricultural N inputs to guarantee food security and rehabilitation and protection of soils to minimize environmental costs. Moreover, to reduce N pollution of the lake, improving management of human and animal wastes needs to be carefully considered in future.

Zhou, Minghua; Brandt, Patric; Pelster, David; Rufino, Mariana C.; Robinson, Timothy; Butterbach-Bahl, Klaus

2014-10-01

266

Monitoring Water Resources in Pastoral Areas of East Africa Using Satellite Data and Hydrologic Modeling  

NASA Astrophysics Data System (ADS)

The nomadic pastoral communities in East Africa heavily depend on small water bodies and artificial lakes for domestic and livestock uses. The shortage of water in the region has made these water resources of great importance to them and sometimes even the reason for conflicts amongst rival communities in the region. Satellite-based data has significantly transformed the way we track and estimate hydrological processes such as precipitation and evapotranspiration. This approach has been particularly useful in remote places where conventional station-based weather networks are scarce. Tropical Rainfall Measuring Mission (TRMM) satellite data were extracted for the study region. National Oceanic and Atmospheric Administration's (NOAA) Global Data Assimilation System (GDAS) data were used to extract the climatic parameters needed to calculate reference evapotranspiration. The elevation data needed to delineate the watersheds were extracted from the Shuttle Radar Topography Mission (SRTM) with spatial resolution of 90m. The waterholes (most of which have average surface area less than a hectare) were identified using Advanced Space-borne Thermal Emission and Reflection Radiometer (ASTER) images with a spatial resolution of 15 m. As part of National Aeronautics and Space Administration's (NASA) funded enhancement to a livestock early warning decision support system, a simple hydrologic water balance model was developed to estimate daily waterhole depth variations. The model was run for over 10 years from 1998 till 2008 for 10 representative waterholes in the region. Although there were no independent datasets to validate the results, the temporal patterns captured both the seasonal and inter-annual variations, depicting known drought and flood years. Future research includes the installation of staff-gauges for model calibration and validation. The simple modeling approach demonstrated the effectiveness of integrating dynamic coarse resolution datasets such as TRMM with high resolution static datasets such as ASTER and SRTM DEM (Digital Elevation Model) to monitor water resources for drought early warning applications.

Alemu, H.; Senay, G. B.; Velpuri, N.; Asante, K. O.

2008-12-01

267

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

268

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

269

Lake Naivasha, Kenya  

NASA Technical Reports Server (NTRS)

If you live in Europe and buy roses, there is a good chance that they were grown in Kenya specifically, in one of the colossal greenhouses that blot out the once wild shores of Lake Naivasha, 90km north-west of Nairobi. Some 25% of Europe's cut flowers come from Kenya. After a tentative start in the 1980s the industry is now the country's third-largest foreign-currency earner, bringing in $120m a year. But the recent violence in Kenya is having a major impact on the flower growers. A local trade union says 3,000 of the 30,000 workers employed in Naivasha's flower farms have abandoned their jobs. Kenya emerged as a flower power when Israel scaled down its own industry. It has since lost business to neighboring Ethiopia, which offers tax breaks and better security, but Naivasha's perfect intensity of sunlight and days of near-constant length should keep it on top.

The ASTER image was acquired February 2, 2008, covers an area of 25 x 26.6 km, and is located near 0.8 degrees south latitude, 36.4 degrees east longitude.

The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

2008-01-01

270

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

271

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

272

Isotopic Evidence for Neogene Hominid Paleoenvironments in the Kenya Rift Valley  

NASA Astrophysics Data System (ADS)

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 (?13C) 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 ?13C values offer no evidence for a shift from more-closed C3 environments to C4 grassland habitats. If hominids evolved in East Africa during the Late Miocene, they did so in an ecologically diverse setting.

Kingston, John D.; Marino, Bruno D.; Hill, Andrew

1994-05-01

273

Isotopic evidence for neogene hominid paleoenvironments in the kenya rift valley.  

PubMed

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(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(13)C values offer no evidence for a shift from more-closed C3 environments to C4 grassland habitats. If hominids evolved in East Africa during the Late Miocene, they did so in an ecologically diverse setting. PMID:17830084

Kingston, J D; Hill, A; Marino, B D

1994-05-13

274

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.

Mller-Steinhagen, H.; Trieb, F.

2009-04-01

275

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

276

Identification of snails within the Bulinus africanus group from East Africa by multiplex SNaPshot trade mark analysis of single nucleotide polymorphisms within the cytochrome oxidase subunit I.  

PubMed

Identification of populations of Bulinus nasutus and B. globosus from East Africa is unreliable using characters of the shell. In this paper, a molecular method of identification is presented for each species based on DNA sequence variation within the mitochondrial cytochrome oxidase subunit I (COI) as detected by a novel multiplexed SNaPshotTM assay. In total, snails from 7 localities from coastal Kenya were typed using this assay and variation within shell morphology was compared to reference material from Zanzibar. Four locations were found to contain B. nasutus and 2 locations were found to contain B. globosus. A mixed population containing both B. nasutus and B. globosus was found at Kinango. Morphometric variation between samples was considerable and UPGMA cluster analysis failed to differentiate species. The multiplex SNaPshotTM assay is an important development for more precise methods of identification of B. africanus group snails. The assay could be further broadened for identification of other snail intermediate host species. PMID:12426591

Stothard, J R; Llewellyn-Hughes, J; Griffin, C E; Hubbard, S J; Kristensen, T K; Rollinson, D

2002-01-01

277

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

278

Prospects and challenges in the introduction of human papillomavirus vaccines in the extended Middle East and North Africa region.  

PubMed

The development of effective and safe human papillomavirus (HPV) vaccines provides a great opportunity to prevent a devastating disease, cervical cancer, and a host of other related diseases. However, the introduction of these vaccines has been slow in the Extended Middle East and North Africa (EMENA) region. Only one country has introduced the vaccine and few countries plan HPV vaccine introduction in the coming 5 years. Several factors influence the slow uptake in the region, including financial constraints, weak infrastructure for adolescent vaccine delivery, competition with high priority vaccines, and lack of reliable data on the burden of HPV disease. Other barriers include cultural and religious sensitivities, as the vaccines are offered to prevent a sexually transmitted disease in young girls. Recommendations to enhance HPV vaccine introduction in EMENA countries include establishing a regional joint vaccine procurement program, enhancing the adolescent vaccination platform, documenting the burden of cervical cancer, strengthening local National Immunization Technical Advisory Groups and designing Information, Education and Communication material that address cultural concerns. This article forms part of a regional report entitled "Comprehensive Control of HPV Infections and Related Diseases in the Extended Middle East and North Africa Region" Vaccine Volume 31, Supplement 6, 2013. Updates of the progress in the field are presented in a separate monograph entitled "Comprehensive Control of HPV Infections and Related Diseases" Vaccine Volume 30, Supplement 5, 2012. PMID:24331821

Jumaan, Aisha O; Ghanem, Soha; Taher, Jalaa; Braikat, Mhammed; Al Awaidy, Salah; Dbaibo, Ghassan S

2013-12-30

279

The physique of young males in east Africa from the biosocial point of view.  

PubMed

The aim of this study is to show the correlation between the physique of Africans from Kenya, Tanzania, Sudan and the conditions of their biosocial environment. All the young men examined were from Kenya (N=423), Tanzania (N= 153) and Sudan (N=154) aged 18 to 30. Based on the taken measurements (height, weight, sitting height, physiognomic leg length and chest, waist, hip, left thigh and left arm circumferences) the following indices were calculated: Body Mass Index (BMI), Rohrer's index and skelic index. The birth date, the number of children per mnage (in family), and the birth sequence of the examined subject were inquired. The measurement results were elaborated (worked out) statistically in accordance with commonly accepted standards. All the information contained in the collected material within the analysed countries was compared. On the basis of the measured traits and calculated indices it was found that the morphological constitution of the men from Sudan differed. Typical for this group are the largest stature length and the lowest weight and waist measurements. Kenyans are similar to Tanzanians, although the latter have higher weight, hip and thigh measurements and lower chest circumference. The characteristics of the examined Africans' morphological structure were analysed in comparison with the data available in literature and relating to the number of children in family, population density, illiteracy and the growth of income and of the HIV/AIDS problem. PMID:16848137

Rebacz, Ewa

2006-06-01

280

The changing pattern of imported malaria in British visitors to Kenya 1987-1990.  

PubMed Central

Following a sudden increase of imported malaria from Kenya in December 1989-January 1990, an investigation was set up to identify risk factors for travellers' malaria. A questionnaire asking for details of travel patterns and compliance with prophylaxis was sent to cases reported over the 6-month Kenyan winter period. Quarterly malaria attack rates between January 1987 and June 1991 were calculated and linked to meteorological conditions in Mombasa. The number of travellers to Kenya has doubled in the 4 years studied and the quarterly rates varied 4-fold over this period. There was no clear seasonal pattern of malaria in travellers, nor was there any clear relation of malaria to coastal rainfall. Compliance with chemoprophylaxis was poor, with only 16% of cases using currently advised regimens. While the annual malaria attack rate per 10,000 travellers decreased by 37% over the study period, the total numbers of malaria cases imported from Kenya rose by 61%, reflecting the increase in the numbers of travellers to the region. As the popularity of East Africa as a tourist destination continues to increase, Kenya will remain an important and significant source of malaria imported into the UK. PMID:8459379

Pryce, D I; Behrens, R H; Bradley, D J

1993-01-01

281

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

282

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

PubMed

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. PMID:24845801

Elhassan, Nuha; Gebremeskel, Eyoab Iyasu; Elnour, Mohamed Ali; Isabirye, Dan; Okello, John; Hussien, Ayman; Kwiatksowski, Dominic; Hirbo, Jibril; Tishkoff, Sara; Ibrahim, Muntaser E

2014-01-01

283

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. PMID:24845801

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

2014-01-01

284

Seismicity of the Earth 1900-2013 East African Rift  

USGS Publications Warehouse

Rifting in East Africa is not all coeval; volcanism and faulting have been an ongoing phenomenon on the continent since the Eocene (~45 Ma). The rifting began in northern East Africa, and led to the separation of the Nubia (Africa) and Arabia plates in the Red Sea and Gulf of Aden, and in the Lake Turkana area at the Kenya-Ethiopia border. A Paleogene mantle superplume beneath East Africa caused extension within the Nubia plate, as well as a first order topographic high known as the African superswell which now includes most of the eastern and southern sectors of the Nubia plate. Widespread volcanism erupted onto much of the rising plateau in Ethiopia during the Eocene-Oligocene (4529 Ma), with chains of volcanoes forming along the rift separating Africa and Arabia. Since the initiation of rifting in northeastern Africa, the system has propagated over 3,000 km to the south and southwest, and it experiences seismicity as a direct result of the extension and active magmatism.

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

2014-01-01

285

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

286

New Evidence For A Reduced Water Balance In East Africa During The Last Glacial Maximum. Implication For Model-data Comparison  

NASA Astrophysics Data System (ADS)

Recent data syntheses for East Africa (15N and 30S, East of 25E) contain con- flicting palaeoenvironmental evidence for the amount of precipitation received at the LGM. Lake level data show apparently wetter conditions for several basins especially south of the equator, whereas palaeovegetation indicates relative uniform aridity. This contradiction means that the performance of GCMs in reconstructing climate over East Africa at the LGM cannot be rigorously tested yet different boundary conditions pro- duce simulations supporting both scenarios. Here, we present three new records from lakes in the data-poor southern part of East Africa, Lake Malawi, L. Massoko and Lake Rukwa. We also re-assess previously published lake level data bases and intro- duce new sites and additional information for key regions. Changes in water level are primarily inferred from diatoms. Our results all point to conditions significantly drier than, or at least as dry as the present during the LGM in both hemispheres. The hydro- logical budget in the African tropics has not only been paced by the orbital forcing that predicts reduced monsoonal precipitation in the northern tropics, but enhanced rainfall in the southern tropics at the LGM. Relative aridity in East Africa is best simulated us- ing computed SSTs rather than CLIMAP values. Low LGM SSTs causing widespread aridity must have been dominant over any orbitally-induced rise in precipitation. The TSouth African monsoonT flow traversed continental areas of the northern tropics that were at least as dry as today and thus brought very little moisture. Reduced vegetation cover and reduced water surfaces may have further intensify aridity in East Africa.

Gasse, F.; Barker, P.

287

Nursing and midwifery regulation and HIV scale-up: establishing a baseline in east, central and southern Africa  

PubMed Central

Introduction Shifting HIV treatment tasks from physicians to nurses and midwives is essential to scaling-up HIV services in sub-Saharan Africa. Updating nursing and midwifery regulations to include task shifting and pre-service education reform can help facilitate reaching new HIV targets. Donor-supported initiatives to update nursing and midwifery regulations are increasing. However, there are gaps in our knowledge of current practice and education regulations and a lack of information to target and implement regulation strengthening efforts. We conducted a survey of national nursing and midwifery councils to describe current nursing and midwifery regulations in 13 African countries. Methods A 30-item survey was administered to a convenience sample of 13 national nursing and midwifery regulatory body leaders in attendance at the PEPFAR-supported African Health Profession Regulatory Collaborative meeting in Nairobi, Kenya on 28 February, 2011. The survey contained questions on task shifting and regulations such as registration, licensure, scope of practice, pre-service education accreditation, continuing professional development and use of international guidelines. Survey data were analyzed to present country-level, comparative and regional findings. Results Task shifting to nurses and midwives was reported in 11 of the 13 countries. Eight countries updated their scope of practice within the last five years; only one reported their regulations to reflect task shifting. Countries vary with regard to licensure, pre-service accreditation and continuing professional development regulations in place. There was no consistency in terms of what standards were used to design national practice and education regulations. Discussion Many opportunities exist to assist countries to modernise regulations to incorporate important advancements from task shifting and pre-service reform. Appropriate, revised regulations can help sustain successful health workforce strategies and contribute to further scale-up HIV services and other global health priorities. Conclusions This study provides fundamental information from which to articulate goals and to measure the impact of regulation strengthening efforts. PMID:23531276

McCarthy, Carey F; Voss, Joachim; Verani, Andre R; Vidot, Peggy; Salmon, Marla E; Riley, Patricia L

2013-01-01

288

When Will we be People as Well? Social Identity and the Politics of Cultural Performance: The Case of the Waata Oromo of East and Northeast Africa  

Microsoft Academic Search

This essay describes the struggle of an indigenous rights activist to obtain ethnic status and political representation for the Waata, former hunter-gatherers who belong to the Oromo-speaking people of East and Northeast Africa. It discusses how this leader is trying to positively redefine the label of 'caste' attributed to the Waata by scholars to explain the ambivalent position occupied by

Aneesa Kassam

2000-01-01

289

Adapting to climate change and disaster risk reduction through sustainable land management: Experiences in Tajikistan, East Africa, US, Argentina and Mongolia  

Technology Transfer Automated Retrieval System (TEKTRAN)

The special session will share and discuss experiences from different regions, namely from Tajikistan, East Africa, US, Argentina and Mongolia. Within the Pilot Program for Climate Resilience (PPCR) in Tajikistan 70 SLM technologies and approaches on how to implement SLM were documented with the Wor...

290

Distribution and movement of scalloped hammerhead Sphryna lewini and smooth hammerhead Sphyrna zygaena sharks along the east coast of southern Africa  

Microsoft Academic Search

Knowledge of population distribution and movement is crucial for the conservation and management of shark species occurring in coastal waters. From 1984 to 2009, 641 scalloped hammerheads Sphyrna lewini, 1 342 smooth hammerheads Sphyrna zygaena and 1 352 unspecified hammerheads Sphyrna spp. were tagged and released along the east coast of South Africa, with recapture rates of 1.9%, 1.5%, and

K M Diemer; B Q Mann; N E Hussey

2011-01-01

291

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

292

Conference report: Second conference of the Middle East and North Africa newborn screening initiative: Partnerships for sustainable newborn screening infrastructure and research opportunities  

Microsoft Academic Search

The second conference of the Middle East and North Africa newborn screening initiative: partnerships for sustainable newborn screen- ing infrastructure and research opportunities was held in Cairo, Arab Republic of Egypt on April 12 to 14, 2008. Policy makers, health ministry representatives, health care providers, and experts from the region, Europe, Asia, and North America participated. The primary outcome was

Danuta Krotoski; Sorrel Namaste; Randa Kamal Raouf; Ibrahim El Nekhely; Michele Hindi-Alexander; Gilian Engelson; James W. Hanson; R. Rodney Howell

2009-01-01

293

A General Survey of Religious Concepts and Art of North, East, South, and West Africa.  

ERIC Educational Resources Information Center

This paper, a summary of a multi-carousel slide presentation, reviews literature on the cultures, religions, and art of African people. Before focusing on West Africa, highlights of the lifestyles, religions, and icons of non-maskmaking cultures of North, West and South African people are presented. Clarification of West African religious concepts

Stewart, Rohn

294

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

Microsoft Academic Search

During an El Nio, 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

295

Natural control of Helicoverpa armigera in smallholder crops in East Africa  

Microsoft Academic Search

The African bollworm, Helicoverpa (=Heliothis) armigera , is one of the worst agricultural pests in Africa, attacking a variety of food and cash crops. For development of sustainable pest management, it is essential to study the ecology and natural mortality factors of the pest, and recently, the need for the assessment of the role of natural enemies, through life table

Berg van de H

1993-01-01

296

Impediments to media communication of social change in family planning and reproductive health: experiences from East Africa.  

PubMed

The media has been employed to increase uptake of Family Planning through behaviour change communication (BCC). Understanding the barriers encountered in effectively undertaking this function would increase the strategy's effectiveness. Sixty journalists from East Africa participated in trainings to enhance their BCC skills for Family Planning in which a qualitative study was nested to identify barriers to effective Family Planning BCC in the region's media. The barriers were observed to be insufficient BCC skills, journalists' conflict of interest, interests of media houses, inaccessible sources of family planning information, editorial ideologies and absence of commercially beneficial demand. Coupled with the historical ideologies of the media in the region, the observed barriers have precipitated ineffective family planning BCC in the regions media. Effective BCC for family planning in the regions media requires capacity building among practitioners and alignment of the concept to the media's and consumers' aspirations. PMID:24069769

Kagurusi, Patrick T

2013-09-01

297

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

298

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

299

A Comparison of Information and Communication Technology Application in New Partnership for Africa's Development (NEPAD) and Non-NEPAD Schools in Kenya  

ERIC Educational Resources Information Center

To date, less than ten percent of secondary schools in Kenya offer computer studies as a subject in the curriculum despite its perceived role in the nation's socio-economic development. The few schools that have an Information Communication Technology (ICT) programme limit the number of candidates who take up the subject, considering it a

Ayere, Mildred A.; Odera, Florence Yukabet; Agak, John Odwar

2010-01-01

300

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

301

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

302

The population genetic structure of Biomphalaria choanomphala in Lake Victoria, East Africa: implications for schistosomiasis transmission.  

PubMed

BackgroundThe freshwater snail Biomphalaria acts as the intermediate host of Schistosoma mansoni, a globally important human parasite. Understanding the population structure of intermediate host species can elucidate transmission dynamics and assist in developing appropriate control methods.MethodsWe examined levels of population genetic structure and diversity in 29 populations of Biomphalaria choanomphala collected around the shoreline of Lake Victoria in Uganda, Kenya and Tanzania, where S. mansoni is hyper-endemic. Molecular markers were utilized to estimate the degree to which snail populations are genetically differentiated from one another.ResultsHigh levels of snail genetic diversity were found coupled with evidence of geographically-determined population structure but low levels of local inbreeding. The data are consistent with an effect of schistosome infection on population structure of intermediate host snails, but other factors, such as habitat and historical demographic changes, could also be important determinants of the degree of population genetic structure in Biomphalaria choanomphala.ConclusionsThe low stratification of populations and high genetic diversity indicates potentially less local compatibility with intermediate snail populations than previously theorized, and highlights the importance of coordinated parasite control strategies across the region. PMID:25406437

Standley, Claire J; Goodacre, Sara L; Wade, Christopher M; Stothard, J

2014-11-19

303

Open system evolution of trachyte and phonolite magmas from the East Africa Rift  

NASA Astrophysics Data System (ADS)

The Quaternary Suswa volcanic system consists of a large shield volcano that developed two nested summit calderas and erupted metaluminous to peralkaline trachyte and phonolite lavas and tuffs. Suswa is adjacent to the Greater Olkaria Volcanic Center, Longonot, Eburru, and Menengai volcanic systems, which erupted trachyte, comendite, and pantellerite. These volcanoes comprise the Central Kenya Peralkaline Province and are the site of active geothermal energy production and exploration. Mafic to intermediate lavas (Elementieta, Ndabibi, and Lolonito-Akira-Tandamara volcanic fields) lie in the rift floor between the shield volcanoes and occur as components of mixed magmas within the complexes. Suswa includes two suites of trachyte-phonolite lavas and tuffs. The first suite (C1) consists of lavas that built the original shield volcano and lavas and tuffs related to the formation of the first caldera; the second suite (C2) consists of lavas and tuffs erupted during and after the formation of the second caldera. Trachyte-carbonate immiscibility has been recorded in C1 ash flow units. The lavas and tuffs of the C2 suite are generally less peralkaline and more silica undersaturated than those of the C1 suite and did not share a common parental magma. Geochemical modeling precludes fractional crystallization as the sole process for Suswa magmas. Instead, assimilation of syenitic material (probably the crystal mush left over from C1 fractional crystallization), resorption, and mixing between the mafic to intermediate lavas satellite to the shield volcanoes have contributed to the composition and eruptive style of these volcanoes.

Anthony, E. Y.; Espejel, V.

2011-12-01

304

The 36 C1 ages of the brines in the Magadi-Natron basin, East Africa  

Microsoft Academic Search

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 36 Cl methodology as a geochemical and hydrological tracer. The

Aaron Kaufman; Mordeckai Margaritz; Michael Paul; Claude Hillaire-Marcel; George Hollos; Elisabetta Boaretto; Maurice Taieb

1990-01-01

305

The sup 36 Cl ages of the brines in the Magadi-Natron basin, east Africa  

Microsoft Academic Search

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 ³⁶Cl methodology as a geochemical and hydrological tracer. The main

A. Kaufman; M. A. Margaritz; G. Hollos; M. Paul; E. Boaretto; C. Hillaire-Marcel; M. Taieb

1990-01-01

306

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

307

Simulated Physical Mechanisms Associated with Climate Variability over Lake Victoria Basin in East Africa  

E-print Network

Simulated Physical Mechanisms Associated with Climate Variability over Lake Victoria Basin in East the physical mechanisms associated with the multiscale variability of the Lake Victoria basin climate advanced in some of the previous studies that Lake Victoria generates its own climate (rainfall) through

Liu, Paul

308

Adapting to climate change: Agricultural system and household impacts in East Africa  

Microsoft Academic Search

The East African region exhibits considerable climatic and topographic variability. Much spatial and temporal variation in the response of different crops to climate change can thus be anticipated. In previous work we showed that a large part of this variation can be explained in terms of temperature and, to a lesser extent, water effects. Here, we summarise simulated yield response

Philip K. Thornton; Peter G. Jones; Gopal Alagarswamy; Jeff Andresen; Mario Herrero

2010-01-01

309

The evolving contribution of border faults and intra-rift faults in early-stage East African rifts: insights from the Natron (Tanzania) and Magadi (Kenya) basins  

NASA Astrophysics Data System (ADS)

In the early stages of continental rifting, East African Rift (EAR) basins are conventionally depicted as asymmetric basins bounded on one side by a ~100 km-long border fault. As rifting progresses, strain concentrates into the rift center, producing intra-rift faults. The timing and nature of the transition from border fault to intra-rift-dominated strain accommodation is unclear. Our study focuses on this transitional phase of continental rifting by exploring the spatial and temporal evolution of faulting in the Natron (border fault initiation at ~3 Ma) and Magadi (~7 Ma) basins of northern Tanzania and southern Kenya, respectively. We compare the morphologies and activity histories of faults in each basin using field observations and remote sensing in order to address the relative contributions of border faults and intra-rift faults to crustal strain accommodation as rifting progresses. The ~500 m-high border fault along the western margin of the Natron basin is steep compared to many border faults in the eastern branch of the EAR, indicating limited scarp degradation by mass wasting. Locally, the escarpment shows open fissures and young scarps 10s of meters high and a few kilometers long, implying ongoing border fault activity in this young rift. However, intra-rift faults within ~1 Ma lavas are greatly eroded and fresh scarps are typically absent, implying long recurrence intervals between slip events. Rift-normal topographic profiles across the Natron basin show the lowest elevations in the lake-filled basin adjacent to the border fault, where a number of hydrothermal springs along the border fault system expel water into the lake. In contrast to Natron, a ~1600 m high, densely vegetated, border fault escarpment along the western edge of the Magadi basin is highly degraded; we were unable to identify evidence of recent rupturing. Rift-normal elevation profiles indicate the focus of strain has migrated away from the border fault into the rift center, where faults pervasively dissect 1.2-0.8 Ma trachyte lavas. Unlike Natron, intra-rift faults in the Magadi basin exhibit primarily steep, little-degraded fault scarps, implying greater activity than Natron intra-rift faults. Numerous fault-associated springs feed water into perennial Lake Magadi, which has no surface drainage input, yet survives despite a high evaporation rate that has created economically viable evaporite deposits. Calcite vein-filled joints are common along fault zones around Lake Magadi, as well as several cm veins around columnar joints that imply isotropic expansion of the fracture network under high pressures of CO2-rich fluids. Our work indicates that the locus of strain in this portion of the EAR transfers from the border fault to the center of the rift basin some time between 3 and 7 million years after rift initiation. This transition likely reflects the evolving respective roles of crustal flexure and magma budget in focusing strain, as well as the hydrothermal fluid budget along evolving fault zones.

Muirhead, J.; Kattenhorn, S. A.; Dindi, E.; Gama, R.

2013-12-01

310

The seismicity of Kenya  

NASA Astrophysics Data System (ADS)

The Kenya Rift Valley, part of the East African Rift System, which extends from Lake Turkana in the north to Lake Magadi in the south, is seismically active. It is surprisingly free of teleseismic events compared to the Western Rift, but experiences considerable microseismic activity releasing the elastic strain energy. This is consistent with the crust having a low tensile strength, probably due to raised geotherms beneath the rift valley arising from lithospheric aattenuation. The microseismicity suggests presently active rifting occurs as far north as 2.5N. This is consistent with recent seismic reflection results in this region which show deep half-grabens beneath Lake Turkana. There is also a broad zone of seismicity subparalleling the rift and displaced about 150 km to the east. This may be associated with a second culmination of the lithosphere-asthenosphere boundary. In order to obtain a better understanding of the rifting process in Kenya it is suggested that a microseismic study be carried out in the Turkana region, whose near surface 3-dimensional morphology has already been examined via the seismic reflection method.

Maguire, P. K. H.; Shah, E. R.; Pointing, A. J.; Cooke, P. A. V.; Khan, M. A.; Swain, C. J.

311

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. PMID:24077927

Brass, Michael

2013-01-01

312

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

PubMed

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. PMID:24077927

Brass, Michael

2013-07-01

313

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

314

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 dcollement, 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 dcollement. 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

315

Nitrogen enrichment during decomposition of mangrove leaf litter in an east African coastal lagoon (Kenya): Relative importance of biological nitrogen fixation  

Microsoft Academic Search

In situ decomposition of senescent leaves of twoabundant mangrove species (Rhizophora mucronataLamarck and Ceriops tagal (Perr) C.B. Rob),enrichment of nitrogen and activity of dinitrogenfixing bacteria during decomposition were investigatedduring both rainy and dry seasons in a tropicalcoastal lagoon (Gazi, Kenya). Rates of leafdecomposition were higher for R. mucronata thanfor C. tagal and were highest, for both species,during rainy season. Rates

A. F. WOITCHIK; B. OHOWA; J. M. KAZUNGU; R. G. RAO; L. GOEYENS; F. DEHAIRS

1997-01-01

316

Tectonics and Volcanism of East Africa as Seen Using Remote Sensing Imagery  

NASA Technical Reports Server (NTRS)

The East African Rift is the largest area of active continental geology. The tectonics of this area has been studied with remote sensing data, including AVHRR, Landsat MSS and TM, SPOT, and electronic still camera from Shuttle. Lineation trends have been compared to centers of volcanic and earthquake activity as well as the trends shown on existing geologic maps. Remote sensing data can be used effectively to reveal and analyze significant tectonic features in this area.

Hutt, Duncan John

1996-01-01

317

New evidence for a reduced water balance in East Africa during the Last Glacial Maximum: implication for model-data comparison  

NASA Astrophysics Data System (ADS)

Some syntheses of lake-level data for the Last Glacial Maximum (LGM) in East Africa (10N and 30S, East of 25E) show apparently wetter conditions than present for some basins, whereas palaeovegetation reconstruction indicates a generally dry climate. PMIP GCM simulations for the LGM support both scenarios for this region when run under different boundary conditions. Here, we compare three new records from lakes in the data-poor southern part of East Africa; Lake Malawi, Lake Massoko, and Lake Rukwa. We also re-assess previously published lake-level data and apply a salinity transfer function to the diatom record from Lake Manyara. Our results show that in contrast to previous interpretations, these lakes were at least as low as today at the LGM and are thus in agreement with the palaeovegetation data. Relative drought across East Africa is best simulated by GCMs that use computed SSTs rather than the higher CLIMAP values. Lower SSTs and the presence of the Northern Hemisphere ice sheets must have been dominant over any monsoon precipitation rise caused by astronomically induced summer insolation enhancement in the southern African tropics.

Barker, Philip; Gasse, Franoise

2003-04-01

318

Mosquito-borne arbovirus surveillance at selected sites in diverse ecological zones of Kenya; 2007 2012  

PubMed Central

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 5years 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

2013-01-01

319

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

NASA Astrophysics Data System (ADS)

Mapping the abundance of 13C in leaf-wax components in surface sediments recovered from the seafloor off northwest Africa (0-35N) reveals a clear pattern of ? 13C distribution, indicating systematic changes in the proportions of terrestrial C 3 and C 4 plant input. At 20N latitude, we find that isotopically enriched products characteristic of C 4 plants account for more than 50% of the terrigenous inputs. This signal extends westward beneath the path of the dust-laden Sahara Air Layer (SAL). High C 4 contributions, apparently carried by January trade winds, also extend far into the Gulf of Guinea. Similar distributions are obtained if summed pollen counts for the Chenopodiaceae-Amaranthaceae and the Poaceae are used as an independent C 4 proxy. We conclude that the specificity of the latitudinal distribution of vegetation in North West Africa and the pathways of the wind systems (trade winds and SAL) are responsible for the observed isotopic patterns observed in the surface sediments. Molecular-isotopic maps on the marine-sedimentary time horizons (e.g., during the last glacial maximum) are thus a robust tool for assessing the phytogeographic changes on the tropical and sub-tropical continents, which have important implications for the changes in climatic and atmospheric conditions.

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

2000-10-01

320

Quality of life and wellbeing among HIV outpatients in East Africa: a multicentre observational study.  

PubMed

BackgroundGlobal health investment has reduced HIV mortality and transmission. However, little is known of patient-reported outcomes alongside ART rollout. This study aimed to measure wellbeing using patient-reported outcome measures (PROMS) among outpatients at PEPFAR-funded facilities.MethodsIn a multicentre 2 country cross-sectional study, adults attending 12 facilities in Kenya and Uganda gave self-reported data on quality of life (physical and mental wellbeing dimensions), functional and a measure of multidimensional problems (physical, psychological, social and spiritual).ResultsAmong the 1,337 participants, multidimensional problems were more common in psychological, spiritual and social domains than in physical. In multivariable analysis using GEE to adjust for facility effect, the mental health subscale of quality of life was lower for people with limited functional status (B=5.27, 95% CI 5.99, 1. 4.56 p<0.001) and higher for wealthier people (B=0.91, 95% CI 0.48, 1.33, p<0.001). The physical health subscale of quality of life was lower for those with limited functional status (B=8.58, 95% CI 9.46 to 7.70, p<0.001) and those who had a caregiver present (B=1.97, 95% CI 3.72 to 0.23, p=0.027), higher for wealthier people (B=1.14, 95% CI 0.65, 1.64, p<0.001), and positively associated with CD4 count (B=1.61, 95% CI 1.082.14, p<0.001). Multidimensional problems were more burdensome for people with limited functional status (B=2.06, 95% CI 2.46 to 1.66, p<0.001), and less burdensome with more education (B=0.63, 95% CI 0.251.00, p=0.001) or ART use (B=0.94, 95% CI 0.341.53, p=0.002).ConclusionsMultidimensional problems are highly prevalent, and worse with declining function. Importantly, ART use does not appear to be protective for self-reported physical and mental dimensions of quality of life. Assessment and management of self-reported wellbeing must form part of HIV care and treatment services to ensure maximum benefit from ART investment. PMID:25403371

Harding, Richard; Simms, Victoria; Penfold, Suzanne; Downing, Julia; Namisango, Eve; Powell, Richard A; Mwangi-Powell, Faith; Moreland, Scott; Gikaara, Nancy; Atieno, Mackuline; Higginson, Irene J

2014-11-18

321

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

322

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

323

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 Damst, Jaap S.

2012-11-01

324

Use of a crop climate modeling system to evaluate climate change adaptation practices: maize yield in East Africa  

NASA Astrophysics Data System (ADS)

Sub Saharan African agriculture is dominated by small-scale farmers and is heavily depend on growing season precipitation. Recent studies indicate that anthropogenic- induced warming including the Indian Ocean sea surface significantly influences precipitation in East Africa. East Africa is a useful region to assess impacts of future climate because of its large rainfall gradient, large percentage of its area being sub-humid or semi-arid, complex climatology and topography, varied soils, and because the population is particularly vulnerable to shifts in climate. Agronomic adaptation practices most commonly being considered include include a shift to short season, drought resistant maize varieties, better management practices especially fertilizer use, and irrigation. The effectiveness of these practices with climate change had not previously been tested. We used the WorldClim data set to represent current climate and compared the current and future climate scenarios of 4 Global Climate Models (GCMs) including a wetter (CCSM) and drier (HadCM3) GCM downscaled to 6 km resolution. The climate data was then used in the process-based CERES maize crop model to simulate the current period (representing 1960- 1990) and change in future maize production (from 2000 to 2050s). The effectiveness of agronomic practices, including short duration maize variety, fertilizer use and irrigation, to reduce projected future yield losses due to climate change were simulated. The GCMs project an increase in maximum temperature during growing season ranging from 1.5 to 3C. Changes in precipitation were dependent on the GCM, with high variability across different topographies land cover types and elevations. Projected warmer temperatures in the future scenarios accelerated plant development and led to a reduction in growing season length and yields even where moisture was sufficient Maize yield changes in 2050 relative to the historical period were highly varied, in excess of +/- 500 kg/ha in many areas. The simulated yield changes in the future were both spatially explicit and dependent on the GCM used. The effectiveness of agronomic practices was highly varied across the region depending on soil type, agro-ecological zone and projected climate change. The results have critical implications for agronomic research and policy. The study challenges using a ';one size fits all' approach in the identification of potential adaptation strategies. The goal is to use models to target local, optimized solutions as part of the broader need for impact assessments at coarser scales.

Moore, N. J.; Alagarswamy, G.; Andresen, J.; Olson, J.; Thornton, P.

2013-12-01

325

Natalizumab treatment for multiple sclerosis: Middle East and North Africa regional recommendations for patient selection and monitoring  

PubMed Central

Background Natalizumab, a highly specific ?4-integrin antagonist, , has recently been registered across the Middle East and North Africa region. It improves clinical and magnetic resonance imaging (MRI) outcomes and reduces the rate of relapse and disability progression in relapsing-remitting multiple sclerosis (MS). Natalizumab is recommended for patients who fail first-line disease-modifying therapy or who have very active disease. Progressive multifocal leukoencephalopathy is a rare, serious adverse event associated with natalizumab. We aim to develop regional recommendations for the selection and monitoring of MS patients to be treated with natalizumab in order to guide local neurological societies. Methods After a review of available literature, a group of neurologists with expertise in the management of MS met to discuss the evidence and develop regional recommendations to guide appropriate use of natalizumab in the region. Results Disease breakthrough is defined as either clinical (relapse or disability progression) or radiological activity (new T2 lesion or gadolinium-enhancing lesions on MRI), or a combination of both. Natalizumab is recommended as an escalation therapy in patients with breakthrough disease based on its established efficacy in Phase III studies. Several factors including prior immunosuppressant therapy, anti-John Cunningham virus (JCV) antibody status and patient choice will affect the selection of natalizumab. In highly active MS, natalizumab is considered as a first-line therapy for naive patients with disabling relapses in association with MRI activity. The anti-JCV antibody test is used to assess anti-JCV antibody status and identify the risk of PML. While seronegative patients should continue treatment with natalizumab, anti-JCV antibody testing every 6months and annual MRI scans are recommended as part of patient monitoring. In seropositive patients, the expected benefits of natalizumab treatment have to be weighed against the risks of PML. Clinical vigilance and follow-up MRI scans remain the cornerstone of monitoring. After 2years of natalizumab therapy, monitoring should include more frequent MRI scans (every 34months) for seropositive patients, and the risk-benefit ratio should be reassessed and discussed with patients. Conclusions Recommendations have been developed to guide neurologists in the Middle East and North Africa on patient selection for natalizumab treatment and monitoring. PMID:24521176

2014-01-01

326

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

327

Africa Aerosol Optical Depth Obtained From MISR  

E-print Network

OpticalDepth Central African Republic Chad Djibouti Egypt Ethiopia Libya Kenya Somalia Sudan Uganda #12;Southern Africa Ethiopia Libya Kenya Somalia Sudan Uganda #12;Southern Africa 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 Mean Seasonal Morocco Niger Nigeria Senegal Sierra Leone Togo Tunisia Western Sahara #12;Southern Africa MISR vs AERONET

Frank, Thomas D.

328

Unequal Access, Unequal Participation: Some Spatial and Socio-Economic Dimensions of the Gender Gap in Education in Africa with Special Reference to Ghana, Zimbabwe and Kenya  

ERIC Educational Resources Information Center

The question of unequal access to education among males and females appears to be universal in the developing world. However, females in Africa seem to suffer more discrimination in terms of access to education. This study revisits the question of gender disparities in educational access in Africa by analyzing data from recent comparative national

Shabaya, Judith; Konadu-Agyemang, Kwadwo

2004-01-01

329

Attitudes and perceptions of urban households in sub-Saharan Africa on water sources, threats and sustainability: A study in Bondo, Kenya  

E-print Network

in the reduction of diarrheal illness. Keys words: Urbanization, water, sub-Saharan Africa, women, participationMethods Attitudes and perceptions of urban households in sub-Saharan Africa on water sources sources of drinking water 3. To understand how women are involved in activities / interventions aimed

Hall, Sharon J.

330

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

331

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

332

The Potential Link Between El Nino and Water Hyacinth Blooms in Winam Gulf of Lake Victoria, East Africa: Evidence from Satellite Imagery  

Microsoft Academic Search

This study evaluates the link between the occurrence of El Nino events in East Africa and water hyacinth blooms in Winam Gulf\\u000a of Lake Victoria using remote sensing technology. A time-series of the Normalized Difference Vegetation Index (NDVI) analyzed\\u000a from data acquired by the multispectral Aqua\\/Terra sensors aboard the Moderate Resolution Imaging Spectroradiometer (MODIS)\\u000a satellite are used to monitor areal

Lawrence M. Kiage; Joyce Obuoyo

333

Where is the western limit of the tropical Indian Ocean seaweed flora? An analysis of intertidal seaweed biogeography on the east coast of South Africa  

Microsoft Academic Search

New, large-scale collections have been made of marine benthic macroalgae (seaweeds) on the east coast of South Africa, and the distributions of shallow-water species were analyzed in detail by multivariate, clustering and -diversity methods. The two northernmost sites are distinct, with a predominance of tropical species, and it is concluded that the changeover from a tropical Indian Ocean flora to

J. J. Bolton; F. Leliaert; O. De Clerck; R. J. Anderson; H. Stegenga; H. E. Engledow; E. Coppejans

2004-01-01

334

A comparison of the heart and muscle total lipid and fatty acid profiles of nine large shark species from the east coast of South Africa  

Microsoft Academic Search

We have assessed the fatty acid profiles of the hearts and different muscle tissues from nine large shark species (Carcharhinus limbatus (blacktip), Carcharhinus obscurus (dusky), Carcharhinus brevipinna (spinner), Carcharhinus leucas (Zambezi\\/bull), Galeocerdo cuvier (tiger), Sphyrna lewini (scalloped hammerhead), Sphyrna zygaena (smooth hammerhead), Carcharodon carcharias (great white) and Carcharias taurus (raggedtooth\\/grey nurse\\/sand tiger)) found off the east coast of South Africa.

Bruce Davidson; Jonathan Sidell; Jeffrey Rhodes; Geremy Cliff

2011-01-01

335

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

336

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

337

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

2014-06-01

338

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 m are considered, and dust-radiation interactions are included (Prez 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 (<10m 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. Prez, E. Cuevas and J.M. Baldasano. 2008. "Aerosol retrospective analysis over North Africa, North-eastern Atlant

Basart, S.; Prez, C.; Cuevas, E.; Baldasano, J. M.

2009-04-01

339

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

340

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

341

Latitudinal Variation In Mangrove Height And Biomass in East Africa Using SRTM Elevation Data  

NASA Astrophysics Data System (ADS)

One of the foundations of biogeography states that productivity and biomass are highest at the equator and decrease as latitude increases. This relationship was confirmed for mangrove ecosystems by Sanger and Snedaker in 1993, based on a review of mangrove biomass and litterfall studies. Recent advances in remote sensing technology have permitted the estimation of mangrove biomass using landcover maps and data from the Shuttle Radar Topography Mission (SRTM). A test of this paradigm of mangrove ecology, using Mozambique as a case study, did not confirm the relationship between mangrove biomass and latitude. In this study, we produced a height and biomass map of mangrove forests of the whole Western Indian Ocean (WIO) region, which spans from Somalia in the North (12N) to South Africa in the S (28S), including Madagascar. Landsat ETM+ data was used to produce landcover maps and SRTM elevation data to produce height and biomass maps for the WIO region. Based on our results, we did not find a significant correlation between latitude and height/biomass in mangrove forests. Our results suggest that that freshwater input and type of geographical setting (lagoons, bays, deltas and open coast) are more important in determining mangrove height and biomass.

Fatoyinbo, T. E.; Simard, M.; Shugart, H. H.

2007-12-01

342

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

343

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

344

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

345

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

346

Late Quaternary hydrology in North Africa and the Near East (Hans Oeschger Medal Lecture)  

NASA Astrophysics Data System (ADS)

The present-day arid-semiarid belt from North Africa to West Asia has experienced huge hydrological changes together with a long history of human civilisations. This belt straddles the boundary between a temperate domain (winter rains linked to the mid-latitude Westerlies), and a subtropical one (rare monsoonal summer precipitation). What are the timing and direction of major hydrological changes in these two domains ? How does the transitional zone migrate through time, and why ? How did human societies respond to changes in water availability ? These questions are addressed using records illustrating both long and short-term environmental changes. At the glacial-interglacial time scale, hydrological changes broadly follow the orbitally-induced Northern Hemisphere summer insolation, but with different regional expressions. In the winter rain domain, the best-dated records come from southern Levant : stable isotope records from speleothems in Israel (120-230 ka) show a remarkable consistency with those from the Eastern Mediterranean Sea(1,2), but the prominant role of rainfall amount or of moisture source isotopic composition on inland records is still debated (1-4); lake-level reconstructions in the Lisan-Dead Sea basin during the past 70 ka demonstrate higher winter rains during the last glacial period than during the Holocene (4,5). However, a new multi-proxy lacustrine record (230 ka) from northern Levant (Yammoneh, Lebanon) shows relatively wet environments during interglacial periods(6,7), suggesting temporal changes in the NS climatic gradients over the Levantine region. Extratropical rainfalls apparently remained predominant over northern Sahara, with a major period of aquifer recharge during the Late Pleistocene(8). Conversely, south of about 25-22 N, the subtropical deserts experienced pluvial periods during interglacials, including the remarkable early-Mid Holocene wetting of the Saharan heart(8). Older pluvial periods, precisely dated in speleothems from Arabia(9) and inferred from lake archives and nearshore marine cores for the Sahara coincide with Marine Isotopic Stages 9, 7, 5.5 and 5.3. Stable isotope and vegetation data indicate that there, precipitation is of tropical origin as a result of an intensified monsoon and a northward migration of the Intertropical Convergence zone. These regional patterns are discussed in the light of general climatic models: roles of orbital forcing, extent/decrease of the northern ice sheet and marine ice, atmospheric content in greenhouse gases, large-scale atmospheric and oceanic circulation and related latitudinal shifts of major climatic belts. At a shorter time-scale, several abrupt changes can also be related to climatic events in high northern latitudes. Pronounced dry spells in the Lisan basin are correlated with Heinrich events(5). The Younger Dryas (YD) and the 8.2 ka events often coincide with arid intervals. During the Holocene, the best-resolved records suggest close relationships between solar activity, northern high-latitude temperature and rainfall intensity. The rapid Mid-Late Holocene aridification leading to modern climates affected both the temperate and subtropical domains. Its mechanisms have been intensively debated. To-date, the best explanations derive from a transient simulation of the North Africa aridification using a general circulation ocean-atmosphere-terrestrial ecosystem model(10); it suggests that the vegetation collapse in southern Sahara is driven by a gradual monsoonal climate response to orbital forcing, increased climate variability and precipitation threshold, rather than a positive vegetation feedback as previously suggested. Long and short-term hydrological changes have obviously induced adjustments or migrations of human societies. For exemple, in the Levant, the YD drought placed the sedentary hunter-gatherers Natufians under severe stress that they circumvented by two strategies : (i) people were forced to switch from a passive dependence on wild grains harvests to the first practices of agriculture; (ii) some populations mi

Gasse, Franoise

2010-05-01

347

Reflexivity and Dialogue: Methodological and Socio-Ethical Dilemmas in Research with HIV-Affected Children in East Africa  

Microsoft Academic Search

This paper presents an integrated discussion of methods and ethics by drawing on participatory research with children in Ethiopia and Kenya. It examines the complex social, ethical, practical and methodological dilemmas of research with HIV-affected children, and explores how we confronted some of these dilemmas before, during and after fieldwork. The paper interrogates the role and limitations of global ethical

Morten Skovdal; Tatek Abebe

2012-01-01

348

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

349

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

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. PMID:21129198

2010-01-01

350

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

351

The 36C1 ages of the brines in the Magadi-Natron basin, East Africa  

NASA Astrophysics Data System (ADS)

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 36Cl 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 36C1/C1 ratio of 2.5 10 -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 36C1/C1 ratios (<1.2 10 -14). By comparing this value with the2.5 10 -14 in recent recharge, one obtains an approximate salt accumulation age of 760 Ka which is consistent with the time of the first appearance of the lake. These older brines also have lower 18O and 2H values which indicate that they were recharged during a climatically different era. The 36C1/C1 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 36C1 production. Such a calculation shows that the hypogene and epigene processes together contribute less than 6% of the total 36C1 present in the lake.

Kaufman, Aaron; Margaritz, Mordeckai; Paul, Michael; Hillaire-Marcel, Claude; Hollos, George; Boaretto, Elisabetta; Taieb, Maurice

1990-10-01

352

Spatial-explicit modeling of social vulnerability to malaria in East Africa  

PubMed Central

Background Despite efforts in eradication and control, malaria remains a global challenge, particularly affecting vulnerable groups. Despite the recession in malaria cases, previously malaria free areas are increasingly confronted with epidemics as a result of changing environmental and socioeconomic conditions. Next to modeling transmission intensities and probabilities, integrated spatial methods targeting the complex interplay of factors that contribute to social vulnerability are required to effectively reduce malaria burden. We propose an integrative method for mapping relative levels of social vulnerability in a spatially explicit manner to support the identification of intervention measures. Methods Based on a literature review, a holistic risk and vulnerability framework has been developed to guide the assessment of social vulnerability to water-related vector-borne diseases (VBDs) in the context of changing environmental and societal conditions. Building on the framework, this paper applies spatially explicit modeling for delineating homogeneous regions of social vulnerability to malaria in eastern Africa, while taking into account expert knowledge for weighting the single vulnerability indicators. To assess the influence of the selected indicators on the final index a local sensitivity analysis is carried out. Results Results indicate that high levels of malaria vulnerability are concentrated in the highlands, where immunity within the population is currently low. Additionally, regions with a lack of access to education and health services aggravate vulnerability. Lower values can be found in regions with relatively low poverty, low population pressure, low conflict density and reduced contributions from the biological susceptibility domain. Overall, the factors characterizing vulnerability vary spatially in the region. The vulnerability index reveals a high level of robustness in regard to the final choice of input datasets, with the exception of the immunity indicator which has a marked impact on the composite vulnerability index. Conclusions We introduce a conceptual framework for modeling risk and vulnerability to VBDs. Drawing on the framework we modeled social vulnerability to malaria in the context of global change using a spatially explicit approach. The results provide decision makers with place-specific options for targeting interventions that aim at reducing the burden of the disease amongst the different vulnerable population groups. PMID:25127688

2014-01-01

353

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, Peter K.; Stager, J.C.; Colman, Steven M.

2003-01-01

354

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.

355

Task shifting for cataract surgery in eastern Africa: productivity and attrition of non-physician cataract surgeons in Kenya, Malawi and Tanzania  

PubMed Central

Background This project examined the surgical productivity and attrition of non-physician cataract surgeons (NPCSs) in Tanzania, Malawi, and Kenya. Methods Baseline (2008-9) data on training, support, and productivity (annual cataract surgery rate) were collected from officially trained NPCSs using mailed questionnaires followed by telephone interviews. Telephone interviews were used to collect follow-up data annually on productivity and semi-annually on attrition. A detailed telephone interview was conducted if a surgeon left his/her post. Data were entered into and analysed using STATA. Results Among the 135 NPCSs, 129 were enrolled in the study (Kenya 88, Tanzania 38, and Malawi 3) mean age 42 years; average time since completing training 6.6 years. Employment was in District 44%, Regional 24% or mission/ private 32% hospitals. Small incision cataract surgery was practiced by 38% of the NPCSs. The mean cataract surgery rate was 188/year, median 76 (range 0-1700). For 39 (31%) NPCSs their surgical rate was more than 200/year. Approximately 22% in Kenya and 25% in Tanzania had years where the cataract surgical rate was zero. About 11% of the surgeons had no support staff. Factors significantly associated with increased productivity were: 1) located at a regional or private/mission hospital compared to a district hospital (OR = 8.26; 95 % CI 2.89 23.81); 2) 3 or more nurses in the eye unit (OR = 8.69; 95% CI 3.27-23.15); 3) 3 or more cataract surgical sets (OR = 3.26; 95% CI 1.48-7.16); 4) a separate eye theatre (OR = 5.41; 95% CI 2.15-13.65); 5) a surgical outreach program (OR = 4.44; 95% CI 1.88-10.52); and 6) providing transport for patients to hospital (OR = 6.39; 95% CI 2.62-15.59). The associations were similar for baseline and follow-up assessments. Attrition during the 3 years occurred in 13 surgeons (10.3%) and was due to retirement or promotion to administration. Conclusions High quality training is necessary but not sufficient to result in cataract surgical activity that meets population needs and maintains surgical skill. Needed are supporting institutions and staff, functioning equipment and programs to recruit and transport patients.

2014-01-01

356

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 unique and open source seismic data sets to improve seismic monitoring 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. In the first phase of this project, seismograms from earthquakes in the Zagros Mountains recorded at regional distances have been inverted for moment tensors, and source depths for the earthquakes have been determined via waveform matching. 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. Nine events with magnitudes between 5 and 6 have been studied so far. Source depths for six of the events are within the upper crust, and three are located within the lower crust. The uncertainty in the source depths of the lower crustal events allows for the possibility that some of them may have even nucleated within the upper mantle. Eight events have thrust mechanisms and one has a strike-slip mechanism. We also report estimates of three-dimensional P- and S-wave velocity structure of the upper mantle beneath the Arabian Peninsula obtained from travel time tomography. Travel time measurements were obtained using a data set provided by King Abdulaziz City for Science and Technology (KACST) for the Saudi Arabia National Digital Seismic Network. The network consists of 38 stations (27 broadband and 11 short period). We augmented the KACST data with delay times measured from permanent stations in the region and the 1995-7 Saudi Arabian PASSCAL Experiment. Tomographic images reveal a low velocity feature in the upper mantle stretching north-south beneath the central portion of the Arabian Shield.

Nyblade, A; Adams, A; Brazier, R; Park, Y; Rodgers, A

2006-07-10

357

A Multi-Model Real Time Forecasting Prototype System in the Mara Basin (Kenya/Tanzania)  

NASA Astrophysics Data System (ADS)

Remote sensing data and hydrologic models can respond to monitoring and forecasting needs in Africa and other poorly gauged regions. We present here the progress to date in developing a multi-model platform to provide hydrologic monitoring and forecasting using real time remote sensing observations. Satellite precipitation products such as CMORPH, TMPA (at 0.25 resolution) and PERSIANN-CCS (at 4km resolution) are used to force two models of different structure. One model is physically based and distributed, and the other is conceptual and lumped at the sub-basin level. The performance of both models is evaluated using different metrics, and the uncertainty in their predictions based on the errors incurred during the historical simulations period is computed. The models were compared and the potential increase in performance from using both models versus a single one will be assessed. This work provides insights into the advantages of a multi-model platform over a single model, with respect to different management and decision-making purposes. The methods were applied to the Mara Basin (Kenya/Tanzania), where growing human demands on water and land use are likely to alter significantly the hydrologic balance of the basin and the ecosystems that depend on it. These efforts are part of the Applied Sciences Team of the NASA SERVIR Program in collaboration with its East Africa Hub at the Regional Center for Mapping of Resources for Development (Nairobi,Kenya).

Serrat-Capdevila, A.; Valdes, J. B.; Valdes, R.; Demaria, E. M.; Durcik, M.; Maitaria, K.; Roy, T.

2013-12-01

358

The Tendaguru formation of southeastern Tanzania, East Africa: An alternating Late Jurassic to Early Cretaceous palaeoenvironment of exceptional status  

NASA Astrophysics Data System (ADS)

Dinosaur remains have inspired considerable scientific interest in the Tendaguru formation of southeastern Tanzania during the 20th century; however, this formation is exceptional in many other respects. The Late Jurassic to Early Cretaceous deposits of the Tendaguru formation in the southwestern Tethys are unique because they represent a marginal marine palaeoenvironment with nonmarine faunal and floral content. It is a threefold succession of marginal marine to terrestrial, carbonate-siliciclastic sediments with cyclic character, consisting of three transgressive-regressive cycles. Revisitation of the type locality (the Tendaguru, a hill approximately 60km northwest of the town of Lindi) by a German-Tanzanian expedition in summer 2000 (Heinrich et al., 2001) resulted in a new standard section (hitherto unpublished, the informal terminology is indicated by the use of lower case in Tendaguru formation), a refined environmental model (Aberhan et al., 2002) and many new insights towards its geology (with evidence of event-sedimentation, Bussert and Aberhan, 2004), biostratigraphy and a better understanding of the Tendaguru palaeo-ecosystems and the palaeoclimate. Within the scope of the designation of a new standard section at the type locality, calcareous microfossils (ostracods, charophytes) have been described to supplement the ongoing discussion about the age and palaeoecology of the Tendaguru formation (Sames, 2008). Although only a few unevenly distributed layers across the section produced calcareous microfossils, the results are very promising. A total of 40 ostracode and 2 charophyte taxa could be distinguished. The non-marine part of the ostracod fauna provides an important contribution to the documentation of Purbeck/Wealden-type nonmarine palaeoenvironments and its microfaunas and -floras previously unknown from East Africa. The marine faunal part belongs to a relatively endemic southern (Gondwana) fauna. Together with other fossil groups, the palaeoecological analysis of microfaunal and -floral assemblages confirms that the former subdivision of the Tendaguru formation into three non-marine intercalated with three marine layers should be recognised as generally only, because the formation is much more complex in detail. Application of calcareous microfossils has been demonstrated to make an important contribution to the interpretation of the Tendaguru formation's palaeoenvironment and is considered highly developable in the future. References: Aberhan, M., Bussert, R., Heinrich, W.-D., Schrank, E., Schultka, S., Sames, B., Kriwet, J. and Kapilima, S., 2002. Palaeoecology and depositional environments of the Tendaguru Beds (Late Jurassic to Early Cretaceous, Tanzania). Mitteilungen aus dem Museum fr Naturkunde in Berlin, Geowissenschaftliche Reihe, 5: 19-44. Bussert, R. and Aberhan, M., 2004. Storms and tsunamis: evidence of event sedimentation in the Late Jurassic Tendaguru Beds of southeastern Tanzania. Journal of African Earth Sciences, 39: 549-555. Heinrich, W.-D., Bussert, R., Aberhan, M., Hampe, O., Kapilima, S., Schrank, E., Schultka, S., Maier, G., Msaky, E., Sames, B. and Chami, R., 2001. The German-Tanzanian Tendaguru Expedition 2000. Mitteilungen aus dem Museum fr Naturkunde Berlin, Geowissenschaftliche Reihe, 20: 223-237. Sames, B., 2008. Application of Ostracoda and Charophyta from the Late Jurassic to Early Cretaceous Tendaguru formation at Tendaguru, Tanzania (East Africa) - Biostratigraphy, Palaeobiogeography and Palaeoecology. Palaeogeography, Palaeoclimatology, Palaeoecology, 264(3-4): 213-229.

Sames, B.

2009-04-01

359

Management of chronic obstructive pulmonary disease in the Middle East and North Africa: results of the BREATHE study.  

PubMed

Chronic obstructive pulmonary disease (COPD) is a potentially severe chronic progressive respiratory condition requiring long-term treatment and frequently involving episodic hospitalisations to manage exacerbations. The objective of this analysis was to document diagnosis, evaluation, treatment and management of COPD-related respiratory symptoms in 1,392 subjects fulfilling an epidemiological definition of COPD identified in a general population sample of 62,086 individuals aged ? 40 years in ten countries in the Middle East and North Africa region (Algeria, Egypt, Jordan, Lebanon, Morocco, Saudi Arabia, Syria, Tunisia, Turkey and United Arab Emirates), together with Pakistan. 442 subjects (31.8%) claimed to have received a diagnosis of COPD from a physician and 287 (20.6%) had undergone spirometry in the previous year. Use of specific treatments for respiratory symptoms was reported by 218 subjects (15.7%). Use of inhaled long-acting bronchodilators together with corticosteroids (53 subjects; 3.8%) and use of oxygen therapy (31 subjects; 2.3%) was very low. 852 subjects (61.2%) had consulted a physician about their respiratory condition at least once in the previous year, with a mean number of consultations of 3.4 3.6. Moreover, 284 subjects (20.4%) had been hospitalised overnight for their COPD, with a mean of 2.3 3.7 hospitalisations per year. Use of all healthcare resources was significantly higher (p < 0.001) in subjects with CAT scores ? 10 than in those with scores < 10, and greater in those with exacerbations than in those without. In conclusion, COPD in the region is under-diagnosed, inadequately evaluated and inadequately treated. Nonetheless, COPD symptoms are responsible for considerable healthcare consumption, with high levels of physician consultation and hospitalisation. PMID:23290703

Idrees, Majdy; Koniski, Marie-Louise; Taright, Samya; Shahrour, Naeem; Polatli, Mehmet; Ben Kheder, Ali; Alzaabi, Ashraf; Iraqi, Ghali; Khattab, Adel; Javed, Arshad; Rashid, Nauman; El Hasnaoui, Abdelkader

2012-12-01

360

Distribution of COPD-related symptoms in the Middle East and North Africa: results of the BREATHE study.  

PubMed

Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality worldwide. However, its epidemiology in many developing countries is poorly characterised. The objective of this analysis was to evaluate respiratory symptoms which could be COPD-related in a large sample of individuals aged ? 40 years in ten countries in the Middle East and North Africa (Algeria, Egypt, Jordan, Lebanon, Morocco, Saudi Arabia, Syria, Tunisia, Turkey and United Arab Emirates), together with Pakistan, using a standardised methodology. A random sample of 457,258 telephone numbers was contacted. A screening questionnaire was administered to each eligible participant, which included six questions relating to respiratory symptoms. Of 65,154 eligible subjects, 62,086 agreed to participate and 61,551 provided usable data. The age- and gender-adjusted prevalence of symptoms (persistent productive cough or breathlessness or both) was 14.3% [95% CI: 14.0-14.6%], ranging from 7.2% in UAE to 19.1% in Algeria. Symptoms were more frequent (p < 0.0001) in women (16.7%) than in men (12.2%). The adjusted prevalence of COPD according to the "epidemiological" definition (symptoms or diagnosis and cigarette use ? 10 pack years) was 3.6% [95% CI: 3.5-3.7%] (range: 1.9% in UAE to 6.1% in Syria). COPD was more frequent (p < 0.0001) in men (5.2%) than in women (1.8%). The frequency of symptoms was significantly higher in cigarette smokers (p< 0.001), as well as in waterpipe users (p < 0.026). In conclusion, the prevalence of COPD in this region seems to be lower than that reported in industrialised countries. Under-reporting and risk factors other than smoking may contribute to this difference. PMID:23290701

Tageldin, Mohamed Awad; Nafti, Salim; Khan, Javaid Ahmed; Nejjari, Chakib; Beji, Majed; Mahboub, Bassam; Obeidat, Nathir M; Uzaslan, Esra; Sayiner, Abdullah; Wali, Siraj; Rashid, Nauman; El Hasnaoui, Abdelkader

2012-12-01

361

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. PMID:22389729

Hotez, Peter J.; Savioli, Lorenzo; Fenwick, Alan

2012-01-01

362

Decadal rainfall variability modes in observed rainfall records over East Africa and their relations to historical sea surface temperature changes  

NASA Astrophysics Data System (ADS)

SummaryDetailed knowledge about the long-term interface of climate and rainfall variability is essential for managing agricultural activities in Eastern African countries. To this end, the space-time patterns of decadal rainfall variability modes over East Africa and their predictability potentials using Sea Surface Temperature (SST) are investigated. The analysis includes observed rainfall data from 1920 to 2004 and global SSTs for the period 1950-2004. Simple correlation, trend and cyclical analyses, Principal Component Analysis (PCA) with VARIMAX rotation and Canonical Correlation Analysis (CCA) are employed. The results show decadal signals in filtered observed rainfall record with 10 years period during March-May (MAM) and October-December (OND) seasons. During June-August (JJA), however, cycles with 20 years period are common. Too much/little rainfall received in one or two years determines the general trend of the decadal mean rainfall. CCA results for MAM showed significant positive correlations between the VARIMAX-PCA of SST and the canonical component time series over the central equatorial Indian Ocean. Positive loadings were spread over the coastal and Lake Victoria regions while negative loading over the rest of the region with significant canonical correlation skills. For the JJA seasons, Atlantic SSTs had negative loadings centred on the tropical western Atlantic Ocean associated with the wet/dry regimes over western/eastern sectors. The highest canonical correlation skill between OND rainfall and the Pacific SSTs showed that El Nio/La Nia phases are associated with wet/dry decades over the region.

Omondi, P.; Awange, J. L.; Ogallo, L. A.; Okoola, R. A.; Forootan, E.

2012-09-01

363

Pleistocene desiccation in East Africa bottlenecked but did not extirpate the adaptive radiation of Lake Victoria haplochromine cichlid fishes.  

PubMed

The Great Lakes region of East Africa, including Lake Victoria, is the center of diversity of the mega-diverse cichlid fishes (Perciformes: Teleostei). Paleolimnological evidence indicates dramatic desiccation of this lake ca. 18,000-15,000 years ago. Consequently, the hundreds of extant endemic haplochromine species in the lake must have either evolved since then or refugia must have existed, within that lake basin or elsewhere, from which Lake Victoria was recolonized. We studied the population history of the Lake Victoria region superflock (LVRS) of haplochromine cichlids based on nuclear genetic analysis (12 microsatellite loci from 400 haplochomines) of populations from Lake Kivu, Lake Victoria, and the connected and surrounding rivers and lakes. Population genetic analyses confirmed that Lake Kivu haplochromines colonized Lake Victoria. Coalescent analyses show a 30- to 50-fold decline in the haplochromine populations of Lake Victoria, Lake Kivu, and the region ca. 18,000-15,000 years ago. We suggest that this coincides with drastic climatic and geological changes in the late Pleistocene. The most recent common ancestor of the Lake Victoria region haplochromines was estimated to have existed about 4.5 million years ago, which corresponds to the first radiation of cichlids in Lake Tanganyika and the origin of the tribe Haplochrominii. This relatively old evolutionary origin may explain the high levels of polymorphism still found in modern haplochromines. This degree of polymorphism might have acted as a "genetic reservoir" that permitted the explosive radiation of hundreds of haplochromines and their array of contemporary adaptive morphologies. PMID:19651614

Elmer, Kathryn R; Reggio, Chiara; Wirth, Thierry; Verheyen, Erik; Salzburger, Walter; Meyer, Axel

2009-08-11

364

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 glacial/interglacial timescales.

Tierney, Jessica E.; Russell, James M.; Huang, Yongsong

2010-03-01

365

Abrupt Climatic Events Observed in Organic-Rich Sediments From Lake Tanganyika, Tropical East Africa, Over the Past 50 kyr  

NASA Astrophysics Data System (ADS)

Abrupt climate changes such as Dansgaard-Oeschger Cycles and Heinrich Events were first detected in high- latitude records, but an increasing number of studies suggest that these rapid changes are actually global events. The degree to which the tropics drive, control and/or respond to such rapid changes is still poorly understood due to a scarcity of data from low-latitude regions. A recently acquired sediment core from Lake Tanganyika, East Africa, provides a unique archive to study abrupt climate events in the tropics throughout the last glaciation. The core provides a continuous, undisturbed and high resolution climate record over the past 100 kyr. An age-depth model based on 25 new radiocarbon dates provides a solid, high-resolution chronology for the past 50 kyr. Throughout this time, several rapid changes in paleoclimate proxy data are observed along the core. Sedimentation rates remained fairly constant from the Holocene until the Last Glacial Maximum (LGM) but increased abruptly from ~80 mm/1000 yr to ~150 mm/1000 yr around 18 kyr BP. At the same time, the sediment record reveals a sudden increase in total organic carbon (TOC) from 4% to 12% indicating a rapid increase in organic matter contributions at the end of the LGM. Abrupt changes in TOC and ?13C values are also found at ~38 kyr, ~30 kyr and ~16 kyr BP, suggesting a possible link to Heinrich events 4, 3 and 1, respectively. Forthcoming very high-resolution analyses, to augment existing low-resolution data, include ?13C, ?15N, C/N ratios and TOC values. Furthermore, TEX86 measurements will be carried out to determine whether the observed changes in organic matter contributions are associated with changes in water temperatures. In combination with the solid 14C chronology, the new data will allow us to precisely determine the onset, timing and nature of abrupt changes and evaluate them in the global context.

Burnett, A. P.; Weyhenmeyer, C. E.; Scholz, C. A.; Swart, P. K.

2006-12-01

366

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

367

Carbon dioxide measurements in tropical east African biomes  

SciTech Connect

From January 1977 through May 1978 atmospheric CO/sub 2/ 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 CO/sub 2/ concentrations were conducted above different biomes. A large diurnal CO/sub 2/ periodicity was observed over land, with daytime drawdowns to 322 ppm and nighttime buildups to more than 400 ppm observed in savannah regions. In and around tropical rain forests, drawdowns to 310 ppm and buildups to more than 400 ppm were regularly observed. On the higher reaches of Mount Kenya, the diurnal CO/sub 2/ cycle was considerably reduced in amplitude, with variations in the range of 2-6 ppm throughout the 16-month study period. On sunny days, the drawdown of CO/sub 2/ was measurable to heights of at least 4000 m above ground level. Other CO/sub 2/ measurements in air over the Indian Ocean (to distances of up to 450 km upwind of the coast) produced fairly consistent concentrations of about 328.5 ppm which did not fluctuate diurnally. The weekly mean CO/sub 2/ concentrations over Kenya appear to have a bimodal structure, with minima occurring in July and January. On the basis of the data collected during the study it appears likely that regular observations at a high-altitude station on Mount Kenya, either with flask sampling or continuous analyzer measurements, are likely to yield data useful for estimates of CO/sub 2/ concentration backgrounds and trends. Also, there is strong evidence that Mount Kenya would be a good location to measure large-scale interhemispheric CO/sub 2/ exchanges and provide a unique base from which to study the effects of the tropical biome on biogeochemical phenomena. 20 references, 12 figures, 2 tables.

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

1981-06-20

368

Mitochondrial DNA diversity in two ethnic groups in southeastern Kenya: perspectives from the northeastern periphery of the Bantu expansion  

PubMed Central

The Bantu languages are widely distributed throughout sub-Saharan Africa. Genetic research supports linguists and historians who argue that migration played an important role in the spread of this language family, but the genetic data also indicates a more complex process involving substantial gene flow with resident populations. In order to understand the Bantu expansion process in east Africa, mtDNA hypervariable region I variation in 352 individuals from the Taita and Mijikenda ethnic groups was analyzed, and we evaluated the interactions that took place between the Bantu- and non-Bantu-speaking populations in east Africa. The Taita and Mijikenda are Bantu-speaking agropastoralists from southeastern Kenya, at least some of whose ancestors probably migrated into the area as part of Bantu migrations that began around 3,000 BCE. Our analyses indicate that they show some distinctive differences that reflect their unique cultural histories. The Taita are genetically more diverse than the Mijikenda with larger estimates of genetic diversity. The Taita cluster with other east African groups, having high frequencies of haplogroups from that region, while the Mijikenda have high frequencies of central African haplogroups and cluster more closely with central African Bantu-speaking groups. The non-Bantu speakers who lived in southeastern Kenya before Bantu speaking groups arrived were at least partially incorporated into what are now Bantu-speaking Taita groups. In contrast, gene flow from non-Bantu speakers into the Mijikenda was more limited. These results suggest a more complex demographic history where the nature of Bantu and non-Bantu interactions varied throughout the area. PMID:23382080

Batai, Ken; Babrowski, Kara B.; Arroyo, Juan Pablo; Kusimba, Chapurukha M.; Williams, Sloan R.

2013-01-01

369

Male involvement for the prevention of mother-to-child HIV transmission: A brief review of initiatives in East, West, and Central Africa.  

PubMed

Current trends in HIV/AIDS research in sub-Saharan Africa (SSA) highlight socially and culturally sensitive interventions that mobilize community members and resources for universal access to HIV prevention, treatment, and care services. These factors are particularly important when addressing the complex social and cultural nature of implementing services for prevention of mother-to-child transmission of HIV (PMTCT). Across the globe approximately 34 % fewer children were infected with HIV through the perinatal or breastfeeding route in 2011 (est. 330,000) than in 2001 (est. 500,000), but ongoing mother-to-child HIV transmission is concentrated in sub-Saharan Africa, where fully 90 % of 2011 cases are estimated to have occurred. Recent literature suggests that PMTCT in Africa is optimized when interventions engage and empower community members, including male partners, to support program implementation and confront the social, cultural and economic barriers that facilitate continued vertical transmission of HIV. In resource-limited settings the feasibility and sustainability of PMTCT programs require innovative approaches to strengthening male engagement by leveraging lessons learned from successful initiatives in SSA. This review presents an overview of studies assessing barriers and facilitators of male participation in PMTCT and new interventions designed to increase male engagement in East, West, and Central Africa from 2000-2013, and examines the inclusion of men in PMTCT programs through the lens of community and facility activities that promote the engagement and involvement of both men and women in transformative PMTCT initiatives. PMID:24633806

Dunlap, Julie; Foderingham, Nia; Bussell, Scottie; Wester, C William; Audet, Carolyn M; Aliyu, Muktar H

2014-06-01

370

Plague in Africa from 1935 to 1949  

PubMed Central

The history of plague in Africa during the period 1935-49 is reviewed. Much of the information derives from a questionnaire sent to all African territories in 1950. The annual incidence of plague in Africa declined, particularly from 1946 onwards. In 1949, under 400 cases were reported, as compared with over 6,000 in 1935. By the end of 1949, plague was still active in the Belgian Congo, Kenya and Tanganyika, Madagascar, and southern Africa. No cases were reported from Egypt, Tunisia, Algeria, Morocco, Senegal, or Uganda during 1949. A comparison of the seasonal incidence of plague with prevailing atmospheric conditions (temperature and rainfall) in African territories shows that human plague is more frequent in warm moist weather60-80F (15-27C)than in hot dry, or cold, weatherover 80F (27C) or under 60F (15C). The highlands of equatorial Africa and of Madagascar appear to provide the optimum environment for the persistence of plague on the domestic (murine) plane and the high-veld and Kalahari of southern Africa on the sylvatic plane. The rat (Rattus rattus) and the multimammate mouse (R. (Mastomys) natalensis) and their fleas Xenopsylla brasiliensis and X. cheopis appear to be mainly responsible for the persistence of the reservoir in the East African highlands; R. rattus and X. cheopis play this role in Madagascar. The gerbils (Tatera and Desmodillus) and their burrow fleas X. philoxera and X. piriei are the main reservoirs of plague in southern Africa. Within these areas, Pasteurella pestis finds an environment suitable for its continued survival; the conditions seem to be comparable to those defined as obtaining in endemic centres in India. Elsewhere in Africa such endemic centres do not appear to exist. PMID:13115987

Davis, D. H. S.

1953-01-01

371

Drying out the Nile? Regional Climate Change and Water Resources in East Africa with a focus on Lake Victoria and Lake Tana  

NASA Astrophysics Data System (ADS)

The East African lakes Victoria and Tana are important local water resources for agriculture, fisheries and hydropower; they are also the main sources of the Nile. In this study we focus on the evaporative and evapotranspirative regimes of the hydrological basins for Lakes Tana and Victoria to determine how regional climate change under the A1B scenario is likely to affect the local and regional hydrology. We show results from a very high resolution (10km) simulation, where the state-of-the-art regional climate model (RCM) HIRHAM5 was driven by the global circulation model (GCM) ECHAM5 under the A1B scenario. Three time-slices have been investigated for present day (1980-1999), mid-century (2046-2065) and end of the 21st century (2080-2099) periods. Our analysis includes a comparison with a coarser 0.44o (~50 km) resolution run which demonstrates the importance of using high resolution (10km or higher) in RCM studies of this type to correctly simulate the seasonal and geographical characteristics of the present day east African monsoon system. The projections also indicate that climate change under the intermediate SRES A1B scenario is expected to cause more frequent failures of the East African rains with important consequences for the region and for the hydrology of the East African Lakes. This work introduces the proposed DACEA (Drivers of Aridity Change in East Africa) project which aims to investigate regional and global teleconnections that affect aridity in East Africa. Future work will combine climate palaeoproxies from Lake Tana and Lake Victoria with model experiments carried out with the EC-Earth coupled Ocean-Atmosphere General Circulation Model and downscaled to very high resolution with the RCM HIRHAM5 to determine regional and global scale influences on the African monsoon system. The HIRHAM5 simulations will be dynamically coupled to a regional hydrological model based on MIKE SHE, to evaluate the consequences and the feedback from the regional hydrology of the lake basins in terms of the East African rains.

Mottram, Ruth; Fox Maule, Cathrine; Thejll, Peter; Stendel, Martin; Drews, Martin; Davies, Sarah; Lamb, Henry

2014-05-01

372

Out of Africa  

ERIC Educational Resources Information Center

Karen Blixen (Isak Dinesen), author of "Out of Africa," said, "God made the world round so people would never be able to see too far down the road." The author embraced this wonderful thought by venturing on a three-week journey to Kenya and Tanzania in search of grand adventure. In this article, the author shares her adventure with her students

Wilbert, Nancy Corrigan

2009-01-01

373

The MACC-II 2007-2008 reanalysis: atmospheric dust evaluation and characterization over Northern Africa and Middle East  

NASA Astrophysics Data System (ADS)

In the present work, atmospheric mineral dust from a MACC-II short reanalysis run for two years (2007-2008), has been evaluated over Northern Africa and Middle East using satellite aerosol products (from MISR, MODIS and OMI satellite sensors), ground-based AERONET data, in-situ PM10 concentrations from AMMA, and extinction vertical profiles from two ground-based lidars and CALIOP. The MACC-II aerosol optical depth (AOD) spatial and temporal (seasonal and interannual) variability shows good agreement with those provided by satellite sensors. The capability of the model to reproduce AOD, ngstrm exponent (AE) and dust optical depth (DOD) from daily to seasonal time-scale is quantified over twenty-six AERONET stations located in eight geographically distinct regions by using statistical parameters. Overall DOD seasonal variation is fairly well simulated by MACC-II in all regions, although the correlation is significantly higher in dust transport regions than in dust source regions. The ability of MACC-II in reproducing dust vertical profiles has been assessed by comparing seasonal averaged extinction vertical profiles simulated by MACC-II under dust conditions with corresponding extinction profiles obtained with lidar instruments at M'Bour and Santa Cruz de Tenerife, and with CALIOP. We find a good agreement in dust layers structures and averaged extinction vertical profiles between MACC-II, the lidars and CALIOP above the marine boundary layer from 1 to 6 km. Surface dust daily mean concentrations from MACC-II reanalysis has been evaluated with daily averaged PM10 at three monitoring stations of the Sahelian Dust Transect. MACC-II correctly reproduces daily to interannual surface dust concentration variability, although it underestimates daily and monthly means all year long, especially in winter and early spring (dry season). MACC-II reproduces well the dust variability recorded along the station-transect which reflects the variability in dust emission by different Saharan sources, but fails in reproducing the sporadic and very strong dust events associated to mesoscale convective systems during the wet season.

Cuevas, E.; Camino, C.; Benedetti, A.; Basart, S.; Terradellas, E.; Baldasano, J. M.; Morcrette, J.-J.; Marticorena, B.; Goloub, P.; Mortier, A.; Berjn, A.; Hernndez, Y.; Gil-Ojeda, M.; Schulz, M.

2014-11-01

374

Effect of Temporally and Spatially Variable Meteorological Forcing on the Stratification Dynamics of Lake Victoria, East Africa  

NASA Astrophysics Data System (ADS)

The annual cycle of stratification of tropical lakes is driven by seasonal changes in cloud cover as it affects solar radiation and net long wave radiation and seasonal changes in wind speed and relative humidity as they affect latent heat fluxes. For large tropical lakes, latent heat fluxes and net long wave radiation vary across the lake due to lake effects but remain largely unquantified, as are the resulting spatial differences in temperature. Here we present meteorological data and surface energy budgets for six stations around Lake Victoria, East Africa, and time series temperature profiles and transect data taken during different times of day and different seasons. Seasonality is determined by the northeast and southeast monsoons and intervening rainy seasons. Winds were higher in the afternoon to the north in the northeast monsoon and higher at night and in the morning to the south during the southeast monsoon. Cloud cover was least during the monsoons. Lakewide, latent heat fluxes range from 150W m-2 to 250 W m-2 in the afternoon with larger values to the north during the northeast monsoon. Values during the morning range from 100 W m-2 to 150 W m-2 but increase to 200 W m-2 - 300 W m-2 to the south and west during the southeast monsoon. The seasonal thermocline is generated during the northeast monsoon due to the higher afternoon winds which mix heat downwards and overall net heating. Holomixis, but with warmer temperatures to the north, occurs during the southeast monsoon due to the accentuated night time cooling and net heat loss. Wind speeds are lower and the diel range of air temperature and relative humidity is higher inshore than off. Consequently, computed monthly heat losses were at least 30% higher offshore and water temperatures are cooler offshore. Scaling analyses indicate that the stratification induced by inflows of cool water to the north at the end of the southeast monsoon are wind driven and that despite the warmer waters inshore which would enable convective circulation, inshore-offshore exchanges are mediated by wind and internal waves.

MacIntyre, S.; Romero, J. R.

2011-12-01

375

Rift propagation at craton margin.: Distribution of faulting and volcanism in the North Tanzanian Divergence (East Africa) during Neogene times  

NASA Astrophysics Data System (ADS)

A revised kinematic model is proposed for the Neogene tectono-magmatic development of the North Tanzanian Divergence where the axial valley in S Kenya splits southwards into a wide diverging pattern of block faulting in association with the disappearance of volcanism. Propagation of rifting along the S Kenya proto-rift during the last 8 Ma is first assumed to have operated by linkage of discrete magmatic cells as far S as the Ngorongoro-Kilimanjaro transverse volcanic belt that follows the margin of cratonic blocks in N Tanzania. Strain is believed to have nucleated throughout the thermally-weakened lithosphere in the transverse volcanic belt that might have later linked the S Kenya and N Tanzania rift segments with marked structural changes along-strike. The North Tanzanian Divergence is now regarded as a two-armed rift pattern involving: (1) a wide domain of tilted fault blocks to the W (Mbulu) that encompasses the Eyasi and Manyara fault systems, in direct continuation with the Natron northern trough. The reactivation of basement fabrics in the cold and intact Precambrian lithosphere in the Mbulu domain resulted in an oblique rift pattern that contrasts with the orthogonal extension that prevailed in the Magadi-Natron trough above a more attenuated lithosphere. (2) To the E, the Pangani horst-like range is thought to be a younger (< 1 Ma) structure that formed in response to the relocation of extension S of the Kilimanjaro magmatic center. A significant contrast in the mechanical behaviour of the stretched lithosphere in the North Tanzanian diverging rift is assumed to have occurred on both sides of the Masai cratonic block with a mid-crustal decoupling level to the W where asymmetrical fault-basin patterns are dominant (Magadi-Natron and Mbulu), whereas a component of dynamical uplift is suspected to have caused the topographic elevation of the Pangani range in relation with possible far-travelled mantle melts produced at depth further N.

Le Gall, B.; Nonnotte, P.; Rolet, J.; Benoit, M.; Guillou, H.; Mousseau-Nonnotte, M.; Albaric, J.; Deverchre, J.

2008-02-01

376

Water-Isotopes (2H, 3H, 18O) to trace the source and timing of recharge in a fractured granite aquifer in Western Kenya, Africa  

NASA Astrophysics Data System (ADS)

The Vihiga District in West Kenya North-West of Lake Victoria is one of the most densely populated areas in Kenya with 1033 person per square kilometer. To find the most suitable location of an own well for a Primary School in this district, springs, school wells and creeks were sampled in the surroundings to get information about the hydrological cycle in the area. The Waluka Primary school (0.02134N, 34.64311E) is situated on the northern slope of the Maragoli Hills 20 km to the North-West of the Nyanzan provincial capital of Kisumu at the eastern shore of Lake Victoria. The hilly relief varies between 1535 - 1675m. The yearly precipitation is between 1200-1600 mm/a (23C mean temperature) with biannual rainy seasons in which the long rains are generally from March to May as the Inter-Tropical Convergence Zone (ITCZ) moves northwards, and the short rains are typically from October to December as the ITCZ retreats southwards. A lateritic soil covers a thin alteration zone above the Precambrian Maragoli-Granite (Saggerson, 1952). Water circulates either in the thin alteration zone or in fault zones cutting through the Precambrian granite. From discharge measurements of two springs and a creek at the end of the dry season (February 2012) a minimum discharge of ca. 10-20 L/s km2 (300-600 mm) can be estimated. The water is of the alkaline sulfate-nitrate type with low mineralization (70-150 ? S/cm, 25C) and a low pH of about 5 to 6. The delta oxygen-18 and deuterium value ranges between -2.84 to -1.98 oand -8.5 to - 3.9 o(VSMOW). The deuterium excess ranges from 11.7-14.2 oThe water of one spring and well close to the school have a tritium content of 1.42 - 1.62 TU. All groundwater has a low arsenium, fluorine and uranium content, which had only a short soil passage. The relatively elevated, but not problematic content in nitrate (10 - 16 mg/L) probaly reflects the intensive agricultural activities in this area. As the mean ? 18O values during the rainy seasons are significantly lower (-3 to -4 o) than in the mean precipitation during the rest of the year (-2.5 to -1.9 o; Mwango, 2003) one can conclude that the main spring 'Anzaya' and the well in the Naboka Secondary School are recharged from deeper faults with water supplied more during the rainy season. The slightly higher d-excess of 13.4-14.2 ocompared to 11.7-12.6 oin the rest of the samples, indicates a somewhat higher recharge area of this two sites with water vapor recycled in the precipitation around the Liailhunuu peak (ca. 1675m). This effect is also supported by spring-water measurements at the Kilimanjaro (d-excess 13.4-6.6 o) 400 km SE. Similarily, the tritium content of 1.42 - 1.62 TU indicate that compared to a mean tritium content of 2 TU in the rain of this area (Mwango, 2003) the mean residence time can be in the range of recent to few years only.

Kralik, Martin; Whylidal, Stefan; Asunah, Francis; Sltenfu, Jrgen

2014-05-01

377

Mortality disparities among groups participating in an East Africa surveying expedition: the Herbert Henry Austin expedition of 1900-1901.  

PubMed

In the late nineteenth and early twentieth centuries, a number of European expeditions traveled to the region of Lake Rudolf, now largely in northern Kenya. Although diverse in intent, many of these were undertaken in the interests of furthering colonial territorial claims. In 1900-1901, Major Herbert Henry Austin led a British expedition down to the lake from Khartoum in the north. Of the 62 African, Arab, and European members of this expedition, only 18 (29%) arrived at its final destination at Lake Baringo in Kenya. Because of a confluence of adverse climatic, social, and political conditions, the expedition ran short of food supplies when it arrived at the northern end of the lake in April 1901. For the next 4months, the members of the expedition struggled down the west side of the lake and beyond. The greatest mortality (91%) occurred among the 32 African transport drivers who were the most marginally nourished at the outset of the trip. The lowest mortality among the Africans on the expedition (15%) occurred among the members of the Tenth Sudanese Rifles Battalion, who had an excellent nutritional status at the start of the expedition. Major Austin himself suffered from severe scurvy with retinal hemorrhages which left him partially blind in his right eye. An analysis of the mortality rates among the groups that participated in this expedition was undertaken. This revealed that poor nutritional status at the start of the trip was predictive of death from starvation. PMID:23943302

Imperato, Pascal James; Imperato, Gavin H; Imperato, Austin C

2013-10-01

378

Most of our social scientists are not institution based they are there for hireResearch consultancies and social science capacity for health research in East Africa  

PubMed Central

There is a serious shortage of senior African social scientists to lead health-related research in Africa. This is despite the existence of many African social science graduates, and decades of Northern funded research programmes intended to develop local capacity. To investigate the barriers to developing health social science research capacity in East Africa, 29 in-depth interviews, informal conversations and a group discussion were conducted with professionals in this field. Respondents explanations for inadequate social science research capacity primarily related to under-development and global economic inequalities. However, a recurrent theme was the predominance of individually contracted research consultancies. These seem to divert university staff from academic research, supporting colleagues and training the next generation of researchers, stunt the institutional capacity of university departments, restrict the sharing of research findings and perpetuate donors control of the research agenda. Although primarily due to macro-economic factors, limited research capacity in sub-Saharan Africa might be ameliorated by modifying the process by which much research is conducted. This exploratory study suggests that institutional research capacity might be strengthened if consultancy research were commissioned through institutions, rather than individuals, with the payment of substantial overheads. PMID:17826877

Wight, Daniel

2008-01-01

379

Facing Kenya's energy predicament  

SciTech Connect

Kenya's bleak economic future is not helped by its dependence on foreign oil and lack of fossil-fuel reserves. At a conference on Kenya's energy needs, held in May 1979, options for averting a fuel-food crisis were considered. Recognition of Kenya's resource poverty and the immediate need to establish wood-fuel production products, charcoal conversion, conservation projects, and a research agenda were the main themes of that conference and the bases for a Kenyan energy policy.

O'Keefe, P.; Shakow, D.

1980-06-01

380

HIV among People Who Inject Drugs in the Middle East and North Africa: Systematic Review and Data Synthesis  

PubMed Central

Background It is perceived that little is known about the epidemiology of HIV infection among people who inject drugs (PWID) in the Middle East and North Africa (MENA). The primary objective of this study was to assess the status of the HIV epidemic among PWID in MENA by describing HIV prevalence and incidence. Secondary objectives were to describe the risk behavior environment and the HIV epidemic potential among PWID, and to estimate the prevalence of injecting drug use in MENA. Methods and Findings This was a systematic review following the PRISMA guidelines and covering 23 MENA countries. PubMed, Embase, regional and international databases, as well as country-level reports were searched up to December 16, 2013. Primary studies reporting (1) the prevalence/incidence of HIV, other sexually transmitted infections, or hepatitis C virus (HCV) among PWIDs; or (2) the prevalence of injecting or sexual risk behaviors, or HIV knowledge among PWID; or (3) the number/proportion of PWID in MENA countries, were eligible for inclusion. The quality, quantity, and geographic coverage of the data were assessed at country level. Risk of bias in predefined quality domains was described to assess the quality of available HIV prevalence measures. After multiple level screening, 192 eligible reports were included in the review. There were 197 HIV prevalence measures on a total of 58,241 PWID extracted from reports, and an additional 226 HIV prevalence measures extracted from the databases. We estimated that there are 626,000 PWID in MENA (range: 335,0001,635,000, prevalence of 0.24 per 100 adults). We found evidence of HIV epidemics among PWID in at least one-third of MENA countries, most of which are emerging concentrated epidemics and with HIV prevalence overall in the range of 10%15%. Some of the epidemics have however already reached considerable levels including some of the highest HIV prevalence among PWID globally (87.1% in Tripoli, Libya). The relatively high prevalence of sharing needles/syringes (18%28% in the last injection), the low levels of condom use (20%54% ever condom use), the high levels of having sex with sex workers and of men having sex with men (15%30% and 2%10% in the last year, respectively), and of selling sex (5%29% in the last year), indicate a high injecting and sexual risk environment. The prevalence of HCV (31%64%) and of sexually transmitted infections suggest high levels of risk behavior indicative of the potential for more and larger HIV epidemics. Conclusions Our study identified a large volume of HIV-related biological and behavioral data among PWID in the MENA region. The coverage and quality of the data varied between countries. There is robust evidence for HIV epidemics among PWID in multiple countries, most of which have emerged within the last decade and continue to grow. The lack of sufficient evidence in some MENA countries does not preclude the possibility of hidden epidemics among PWID in these settings. With the HIV epidemic among PWID in overall a relatively early phase, there is a window of opportunity for prevention that should not be missed through the provision of comprehensive programs, including scale-up of harm reduction services and expansion of surveillance systems. Please see later in the article for the Editors' Summary PMID:24937136

Mumtaz, Ghina R.; Weiss, Helen A.; Thomas, Sara L.; Riome, Suzanne; Setayesh, Hamidreza; Riedner, Gabriele; Semini, Iris; Tawil, Oussama; Akala, Francisca Ayodeji; Wilson, David; Abu-Raddad, Laith J.

2014-01-01

381

Methanotrophy and chemoautotrophy within the redox gradient of a large and deep tropical lake (Lake Kivu, East Africa)  

NASA Astrophysics Data System (ADS)

Lake Kivu (East Africa) is a large (2370 km2) and deep (maximum depth of 485 m) meromictic lake. Its vertical structure consists of an oxic and nutrient-poor mixed layer down to 70 m maximum, and a permanently anoxic monimolimnion rich in dissolved gases (methane and carbon dioxide) and inorganic nutrients. Seasonal variation of the vertical position of the oxic-anoxic interface is driven by contrasting precipitation and wind speed regimes between rainy (October-May) and dry (June-September) season, the latter being characterized by a deepening of the oxic zone, and an increased input of dissolved gases and inorganic nutrients. Our work aimed at quantifying methanotrophic and chemoautotrophic production within the redox gradient of Lake Kivu and identifying the micro-organisms involved in these processes using phospholipid-derived fatty acid markers and their carbon stable isotope composition. Our approach combined both natural stable isotope abundance analysis and 13C-labelling (13C-DIC ; 13C-CH4) experiments. Sampling was carried out at two stations in Lake Kivu during rainy (February 2012) and dry (September 2012) season conditions. Methanotrophic bacterial production rates were highly variable (from 0.1 to 7.0 ?mol C L-1 d-1), but maximum values were always observed at the oxic-anoxic interface when the CH4:O2 ratio varied between 0.1 and 10, suggesting that the majority of methane was oxidized aerobically. Furthermore, strong stable isotope labelling of monounsaturated C16 fatty acids indicate that active methane oxidizers were related to the group of type I aerobic methanotrophs (gammaproteobacteria). Despite the dominance of aerobic methane oxidation, significant methanotrophic bacterial production rates were found below the oxic-anoxic interface during the rainy season, indicating that at least a fraction of the upcoming methane may be oxidized anaerobically. This observation was further confirmed by the strong labelling at these depths of the 10Me16:0 fatty acid, biomarker for sulphate-reducing bacteria, the syntrophic partners of anaerobic methane-oxidizing archaea. The methanotrophic bacterial growth efficiency (MBGE) was variable (2-50%), and inversely related to methane concentration. Maximum chemoautotrophic bacterial production rates were recorded well below the oxycline, in sulfidic waters. However, during the rainy season, significant dark C fixation rates were measured near the oxic-anoxic interface, in a nitracline where sulphide was absent, suggesting that another energy source was involved. Incorporation of labelled carbon in the 16:1?9c ; 16:1?7c and 18:1?7 fatty acids suggest that the active chemoautotrophic organisms belong to the phylum proteobacteria. Together, the vertically integrated methanotrophic and chemoautotrophic production rates were 31 mmol m-2 d-1 and 41 mmol-2 d-1 during the rainy and dry season, respectively. These values are comparable to the net phytoplanktonic production rates in Lake Kivu ranging between 12 and 160 mmol m-2 d-1 (on average 52 mmol m-2 d-1). Our results indicate that methanotrophs and chemoautotrophs contribute substantially to the carbon cycle in Lake Kivu.

Morana, Cedric; Borges, Alberto V.; Darchambeau, Franois; Roland, Fleur; Montante, Laetitia; Descy, Jean-Pierre; Bouillon, Steven

2014-05-01

382

Further hominids from the Plio-Pleistocene of Koobi Fora, Kenya.  

PubMed

Fifty-eight new fossil hominids from Plio-Pleistocene sediments east of Lake Turkana, Kenya, are described. They include cranial, mandibular, dental, and postcranial parts. Some are illustrated. PMID:3933357

Leakey, R E; Walker, A C

1985-06-01

383

A new Late Miocene great ape from Kenya and its implications for the origins of African great apes and humans  

PubMed Central

Extant African great apes and humans are thought to have diverged from each other in the Late Miocene. However, few hominoid fossils are known from Africa during this period. Here we describe a new genus of great ape (Nakalipithecus nakayamai gen. et sp. nov.) recently discovered from the early Late Miocene of Nakali, Kenya. The new genus resembles Ouranopithecus macedoniensis (9.68.7 Ma, Greece) in size and some features but retains less specialized characters, such as less inflated cusps and better-developed cingula on cheek teeth, and it was recovered from a slightly older age (9.99.8 Ma). Although the affinity of Ouranopithecus to the extant African apes and humans has often been inferred, the former is known only from southeastern Europe. The discovery of N. nakayamai in East Africa, therefore, provides new evidence on the origins of African great apes and humans. N. nakayamai could be close to the last common ancestor of the extant African apes and humans. In addition, the associated primate fauna from Nakali shows that hominoids and other non-cercopithecoid catarrhines retained higher diversity into the early Late Miocene in East Africa than previously recognized. PMID:18024593

Kunimatsu, Yutaka; Nakatsukasa, Masato; Sawada, Yoshihiro; Sakai, Tetsuya; Hyodo, Masayuki; Hyodo, Hironobu; Itaya, Tetsumaru; Nakaya, Hideo; Saegusa, Haruo; Mazurier, Arnaud; Saneyoshi, Mototaka; Tsujikawa, Hiroshi; Yamamoto, Ayumi; Mbua, Emma

2007-01-01

384

Trends and variability in East African rainfall and temperature observations  

NASA Astrophysics Data System (ADS)

The economy of East Africa is highly dependent on agriculture, leading to a strong vulnerability of local society to fluctuations in seasonal rainfall amounts, including extreme events. Hence, the knowledge about the evolution of seasonal rainfall under future climate conditions is crucial. Rainfall regimes over East Africa are influenced by multiple factors, including two monsoon systems, several convergence zones and the Rift Valley lakes. In addition, local conditions, like topography, modulate the large-scale rainfall pattern. East African rainfall variability is also influenced by various teleconnections like the Indian Ocean Zonal Mode and El Nio Southern Oscillation. Regarding future climate projections, regional and global climate models partly disagree on the increase or decrease of East African rainfall. The specific aim of the present study is the acquirement of historic data from weather stations in East Africa (Kenya, Tanzania, Ruanda and Uganda), the use of gridded satellite (rainfall) products (ARC2 and TRMM), and three-dimensional atmospheric reanalysis (e.g., ERA-Interim) to quantify climate variability in the recent past and to understand its causes. Climate variability and trends, including changes in extreme events, are evaluated using ETCCDI climate change and standardized precipitation indices. These climate indices are determined in order to investigate the variability of temperature and rainfall and their trends with the focus on most recent decades. In the follow-up, statistical and dynamical analyses are conducted to quantify the local impact of pertinent large-scale modes of climate variability (Indian Ocean Zonal Mode, El Nio Southern Oscillation, Sea Surface Temperature of the Indian Ocean).

Seregina, Larisa; Ermert, Volker; Fink, Andreas H.; Pinto, Joaquim G.

2014-05-01

385

Geophysical evidence for a failed Jurassic rift and triple junction in Kenya  

NASA Astrophysics Data System (ADS)

The interpretation of new and pre-existing aeromagnetic survey data for Kenya, in conjunction with published gravity data, indicates the existence of a palaeo-triple junction of Jurassic age in eastern Kenya. Two arms, represented by the Mombasa coast and the Somali coast respectively, developed into a part of the Indian Ocean. The third arm, which is now concealed by a cover of Quaternary sediments and volcanic rocks, remains as a rifted, sediment-filled trough extending at least as far northwest as the presently active East Africa Rift in Lake Turkana. It has a remarkable similarity, both in scale and geometry, with the Benue Trough of the Niger Delta. As with the Niger Delta, the present Kenyan coastline is not indicative of the true continental margin, as extensive sedimentation has occurred beyond the continental edge in the region of the triple junction since dispersal. Delineation of the true continental margin from aeromagnetic evidence allows pre-drift Madagascar to be re-assembled in closer proximity to the coast than indicated in many reconstructions though the geological evidence supporting this pre-drift position is still controversial.

Reeves, C. V.; Karanja, F. M.; MacLeod, I. N.

1987-01-01

386

Structural style of the Turkana Rift, Kenya  

SciTech Connect

Multifold seismic reflection and geologic mapping in part of the eastern branch of the East African Rift system of northern Kenya reveal a major rift structure containing at least 3 km of Neogene sediment fill beneath Lake Turkana. This includes a series of half-graben basins, with centrally located quaternary volcanic centers, which are linked end-to-end by structural accommodation zones. Whereas the geometry of rifting is similar to that of the nonvolcanic western branch of the East African Rift system, the Turkana half-grabens are much smaller and may reflect extension of a thinner lithosphere or development of more closely spaced fracture patterns during rift evolution, or both.

Dunkelman, T.J.; Karson, J.A.; Rosendahl, B.R.

1988-03-01

387

Structural style of the Turkana Rift, Kenya  

NASA Astrophysics Data System (ADS)

Multifold seismic reflection and geologic mapping in part of the eastern branch of the East African Rift system of northern Kenya reveal a major rift structure containing at least 3 km of Neogene sediment fill beneath Lake Turkana. This includes a series of half-graben basins, with centrally located Quaternary volcanic centers, which are linked end-to-end by structural accommodation zones. Whereas the geometry of rifting is similar to that of the nonvolcanic western branch of the East African Rift system, the Turkana half-grabens are much smaller and may reflect extension of a thinner lithosphere or development of more closely spaced fracture patterns during rift evolution, or both.

Dunkelman, Thomas J.; Karson, Jeffrey A.; Rosendahl, Bruce R.

1988-03-01

388

The decline of the native fishes of lakes Victoria and Kyoga (East Africa) and the impact of introduced species, especially the Nile perch, Lates niloticus , and the Nile tilapia, Oreochromis niloticus  

Microsoft Academic Search

There has been a decline, and in some cases an almost total disappearance, of many of the native fish species of lakes Victoria and Kyoga in East Africa since the development of the fisheries of these lakes was initiated at the beginning of this century. The Nile perch, Lates niloticus, a large, voracious predator which was introduced into these lakes

Richard Ogutu-Ohwayo

1990-01-01

389

Molecular Genetic Diversity of Hepatitis B Virus in Kenya  

Microsoft Academic Search

Eight genotypes of hepatitis B virus (A-H) and subgenotypes have been recognized worldwide. However, there is limited information on prevalent genotypes in many countries in Africa. This study was undertaken to determine the hepatitis B virus (HBV) genotypes in Kenya. Seropositive HBV blood samples from a blood donor setting were used in the study. HBV genotypes were determined in 52

Joseph Mwangi; Zipporah Nganga; Elijah Songok; Joyceline Kinyua; Nancy Lagat; Joseph Muriuki; Raphael Lihana; Samoel Khamadi; Saida Osman; Raphael Lwembe; Michael Kiptoo; Matilu Mwau; Ruth Chirchir; Solomon Mpoke; Jack Nyamongo; Fred Okoth; Rika Yamada; Seiji Kageyama; Hiroshi Ichimura

2008-01-01

390

Shocking elephants: Fences and crop raiders in Laikipia District, Kenya  

Microsoft Academic Search

Electric fences and other barriers to prevent movement of elephants onto arable land are increasingly important conservation tools in Africa, as elephant populations become isolated by areas of increasing human settlement. In Laikipia District in Kenya, crop raiding by elephants is a serious problem, and many different types of elephant barriers have been built over the last 30 years. In

C. R. Thouless; J. Sakwa

1995-01-01

391

Fish Assemblage Patterns as a Tool to Aid Conservation in the Olifants River Catchment (East), South Africa  

EPA Science Inventory

South Africa has committed to address freshwater conservation at the catchment scale, using a combination of landscape-level and species-level features as surrogates of freshwater biodiversity. Here we examined fishes in the Olifants catchment, where multiple anthropogenic pressu...

392

Prediction, Assessment of the Rift Valley fever Activity in East and Southern Africa 2006 - 2008 and Possible Vector Control Strategies  

Technology Transfer Automated Retrieval System (TEKTRAN)

Historical outbreaks of Rift Valley fever (RVF) since the early 1950s have been associated with cyclical patterns of the El Nino/Southern Oscillation (ENSO) phenomenon which results in elevated and widespread rainfall over the RVF endemic areas of Africa. Using satellite measurements of global and ...

393

Prediction, Assessment of the Rift Valley Fever Activity in East and Southern Africa 2006 - 2008 and Possible Vector Control Strategies  

Technology Transfer Automated Retrieval System (TEKTRAN)

Historical episodic outbreaks of Rift Valley fever (RVF) since the early 1950s have been associated with cyclical patterns (El Nio and La Nia) of El Nio Southern Oscillation (ENSO) phenomenon which results in elevated and widespread rainfall over the RVF endemic areas of Africa. Using satellite ...

394

A High-Resolution Paleoclimate Record Spanning the Past 25,000 Years in Southern East Africa  

Microsoft Academic Search

High-resolution profiles of the mass accumulation rate of biogenic silica and other geochemical proxies in two piston cores from northern Lake Malawi provide a climate signal for this part of tropical Africa spanning the past 25,000 years. The biogenic silica mass accumulation rate was low during the relatively dry late Pleistocene, when the river flux of silica to the lake

Thomas C. Johnson; Erik T. Brown; James McManus; Sylvia Barry; Philip Barker; Franoise Gasse

2002-01-01

395

Prevalence and diversity of cystic echinococcosis in livestock in Maasailand, Kenya.  

PubMed

Cystic echinococcosis (CE) is a zoonotic disease caused by several members of the Echinococcus granulosus species complex. In East Africa, several species/strains are known to occur in livestock and humans, but host preferences, relative frequencies and spatial distribution of these taxa are poorly known. Here, we contribute livestock data for Maasailand of southern Kenya. Total CE prevalence was 25.8 % in cattle (151/587), 16.5 % in sheep (71/430) and 10.8 % in goats (21/194), which is a significant increase compared to surveys done about three decades ago. The majority of cysts occurred in the liver (56 % in cattle, 70 % in sheep and 65 % in goats). Molecular characterization by PCR-RFLP and sequencing of parts of the mitochondrial nad-1 gene was done for a subsample of 285 cysts. E. granulosus G1 was dominant in all host species (200 of 201 cysts from cattle, 68 of 69 from sheep and 11 of 15 from goats); the remaining taxa were Echinococcus canadensis G6 (one cyst from sheep, four from goats) and Echinococcus ortleppi (one cyst from cattle). Considering cyst fertility, sheep appear to be the most important hosts for E. granulosus G1, while goats were found to be suitable hosts for E. canadensis G6 (three of four cysts were fertile). For the first time, E. ortleppi was found in cattle from southern Kenya. Our data show an intense and possibly increasing level of CE transmission in southern Kenya, and the predominance of E. granulosus G1, which appears to be particularly pathogenic to humans, calls for urgent control measures. PMID:22915272

Addy, Francis; Alakonya, Amos; Wamae, Njeri; Magambo, Japhet; Mbae, Cecilia; Mulinge, Erastus; Zeyhle, Eberhard; Wassermann, Marion; Kern, Peter; Romig, Thomas

2012-12-01

396

Trends of human immunodeficiency virus type-1 infection in female prostitutes and males diagnosed with a sexually transmitted disease in Djibouti, east Africa.  

PubMed

A cross-sectional serosurvey for human immunodeficiency virus type 1 (HIV-1) was conducted during the first quarter of 1991 among high risk groups in Djibouti, East Africa, and compared with previous surveys in 1987, 1988, and 1990. The survey demonstrated evidence of HIV-1 infection in 36.0% (n = 292) of street prostitutes, 15.3% (n = 360) of prostitutes working as bar hostesses, and 10.4% (n = 193) of males diagnosed with a sexually transmitted disease. By multivariate modeling, HIV-1 seropositivity in prostitutes was associated with Ethiopian nationality, working as a street prostitute, and residing in Djibouti for two years or less. We suggest that prostitution, particularly street prostitution, is a major route of HIV-1 transmission in Djibouti. PMID:8517486

Rodier, G R; Couzineau, B; Gray, G C; Omar, C S; Fox, E; Bouloumie, J; Watts, D

1993-05-01

397

A comparison of the heart and muscle total lipid and fatty acid profiles of nine large shark species from the east coast of South Africa.  

PubMed

We have assessed the fatty acid profiles of the hearts and different muscle tissues from nine large shark species (Carcharhinus limbatus (blacktip), Carcharhinus obscurus (dusky), Carcharhinus brevipinna (spinner), Carcharhinus leucas (Zambezi/bull), Galeocerdo cuvier (tiger), Sphyrna lewini (scalloped hammerhead), Sphyrna zygaena (smooth hammerhead), Carcharodon carcharias (great white) and Carcharias taurus (raggedtooth/grey nurse/sand tiger)) found off the east coast of South Africa. While there was generally little variation between the species, all species showed profiles rich in both n6 and n3 polyunsaturated fatty acids compared to terrestrial commercial meats that have low n3. Thus, utilizing skeletal muscle tissues from sharks caught as part of the bycatch when fishing for teleosts would avoid unnecessary wastage of a potentially valuable resource, with all the possible health benefits of high quality protein combined with balanced polyunsaturates, although contamination with high levels of metabolic wastes, such as urea, may be a negative consideration. PMID:20694746

Davidson, Bruce; Sidell, Jonathan; Rhodes, Jeffrey; Cliff, Geremy

2011-03-01

398

Influence of two Wolbachia strains on population structure of East African Drosophila simulans.  

PubMed Central

Drosophila simulans is hypothesized to have originated in continental East Africa or Madagascar. In this study, we investigated evolutionary forces operating on mitochondrial DNA (mtDNA) in populations of D. simulans from Zimbabwe, Malawi, Tanzania, and Kenya. Variation in mtDNA may be affected by positive selection, background selection, demographic history, and/or any maternally inherited factor such as the bacterial symbiont Wolbachia. In East Africa, the wRi and wMa Wolbachia strains associate with the siII or siIII mitochondrial haplogroups, respectively. To ask how polymorphism relates to Wolbachia infection status, we sequenced 1776 bp of mitochondrial DNA and 1029 bp of the X-linked per locus from 79 lines. The two southern populations were infected with wRi and exhibited significantly reduced mtDNA variation, while Wolbachia-uninfected siII flies from Tanzania and Kenya showed high levels of mtDNA polymorphism. These are the first known populations of D. simulans that do not exhibit reduced mtDNA variation. We observed no mitochondrial variation in the siIII haplogroup regardless of Wolbachia infection status, suggesting positive or background selection. These populations offer a unique opportunity to monitor evolutionary dynamics in ancestral populations that harbor multiple strains of Wolbachia. PMID:14704179

Dean, Matthew D; Ballard, Kirrie J; Glass, Anne; Ballard, J William O

2003-01-01

399

Chronic obstructive pulmonary disease in the adult population within the Middle East and North Africa region: rationale and design of the BREATHE study.  

PubMed

The objective of the BREATHE study was to estimate the regional prevalence of chronic obstructive pulmonary disease (COPD) symptoms within the general population in the Middle East/North Africa (MENA) region and to document risk factors, disease characteristics and management using a standardised methodology. This was an observational population-based survey performed in ten countries in the Middle East and North Africa (Algeria, Egypt, Jordan, Lebanon, Morocco, Saudi Arabia, Syria, Tunisia, Turkey and United Arab Emirates), together with Pakistan. A general population sample of 10,000 subjects ? 40 years of age in each country or zone was generated from random telephone numbers. Structured interviews were proposed by telephone. A screening questionnaire was administered to each subject collecting information on respiratory symptoms and smoking habits. Subjects with chronic bronchitis or breathlessness and smoking ? 10 pack years fulfilled the epidemiological definition of COPD ("COPD" population). This population then completed a full disease questionnaire, the COPD Assessment Test (CAT) and a cost-of-disease questionnaire. A randomly selected sample was also assessed by spirometry. In all, 457,258 telephone numbers were generated and contact was established with 210,121 subjects, of whom 65,154 were eligible and 62,086 accepted to participate. The overall response rate was 74.2%. 2,187 (3.5%) subjects fulfilled the criteria for the "COPD" population. Evaluable spirometry data were obtained from 1,847 (14.2%) subjects to whom it was proposed. The BREATHE study has collected a large amount of information on COPD variables from a representative sample of the general population of countries in the MENA region, which can be compared with other regional COPD initiatives. PMID:23290702

El Hasnaoui, Abdelkader; Rashid, Nauman; Lahlou, Aicha; Salhi, Hocine; Doble, Adam; Nejjari, Chakib

2012-12-01

400

Suboptimal management of rheumatoid arthritis in the Middle East and Africa: could the EULAR recommendations be the start of a solution?  

PubMed

Although the prevalence of RA in the Middle East and Africa is comparable with that in other parts of the world, evidence indicates that its management in this region is suboptimal for a variety of reasons, including misconceptions and misunderstandings about the disease's prevalence and severity in the region, compounded by the lack of local epidemiological and health-economic data around the disease; the perception that RA is a low priority compared with other more prevalent conditions; delayed diagnosis, referral and treatment; and a lack of a region-specific, evidence-based management approach. In the absence of such an approach, the EULAR treatment recommendations may provide a useful starting point for the creation of guidelines to suit local circumstances. However, although agreement with the EULAR recommendations is high, many barriers prevent their implementation in clinical practise, including lack of timely referral to rheumatologists; suboptimal use of synthetic DMARDs; poor access to biologics; lack of awareness of the burden of RA among healthcare professionals, patients and payers; and lack of appropriate staffing levels.To optimise the management of RA in the Middle East and Africa, will require a multi-pronged approach from a diverse group of stakeholders-including local, national and regional societies, such as the African League of Associations in Rheumatology and International League of Associations for Rheumatology, and service providers-to collect data on the epidemiology and burden of the disease; to increase awareness of RA and its burden among healthcare professionals, payers and patients through various educational programmes; to encourage early referral and optimise use of DMARDs by promoting the EULAR treatment recommendations; to encourage the development of locally applicable guidelines based on the EULAR treatment recommendations; and to facilitate access to drugs and the healthcare professionals who can prescribe and monitor them. PMID:23274756

El Zorkany, Bassel; Alwahshi, Humaid A; Hammoudeh, Mohamed; Al Emadi, Samar; Benitha, Romela; Al Awadhi, Adel; Bouajina, Elyes; Laatar, Ahmed; El Badawy, Samir; Al Badi, Marzooq; Al-Maini, Mustafa; Al Saleh, Jamal; Alswailem, Ramiz; Ally, Mahmood Moosa Tar Mahomed; Batha, Wafaa; Djoudi, Hachemi; El Garf, Ayman; El Hadidi, Khaled; El Marzouqi, Mohamed; Hadidi, Musa; Maharaj, Ajesh Basantharan; Masri, Abdel Fattah; Mofti, Ayman; Nahar, Ibrahim; Pettipher, Clive Allan; Spargo, Catherine Elizabeth; Emery, Paul

2013-02-01

401

Diet of Theropithecus from 4 to 1 Ma in Kenya.  

PubMed

Theropithecus was a common large-bodied primate that co-occurred with hominins in many Plio-Pleistocene deposits in East and South Africa. Stable isotope analyses of tooth enamel from T. brumpti (4.0-2.5 Ma) and T. oswaldi (2.0-1.0 Ma) in Kenya show that the earliest Theropithecus at 4 Ma had a diet dominated by C4 resources. Progressively, this genus increased the proportion of C4-derived resources in its diet and by 1.0 Ma, had a diet that was nearly 100% C4-derived. It is likely that this diet was comprised of grasses or sedges; stable isotopes cannot, by themselves, give an indication of the relative importance of leaves, seeds, or underground storage organs to the diet of this primate. Theropithecus throughout the 4- to 1-Ma time range has a diet that is more C4-based than contemporaneous hominins of the genera Australopithecus, Kenyanthropus, and Homo; however, Theropithecus and Paranthropus have similar proportions of C4-based resources in their respective diets. PMID:23733967

Cerling, Thure E; Chritz, Kendra L; Jablonski, Nina G; Leakey, Meave G; Manthi, Fredrick Kyalo

2013-06-25

402

Diet of Theropithecus from 4 to 1 Ma in Kenya  

PubMed Central

Theropithecus was a common large-bodied primate that co-occurred with hominins in many Plio-Pleistocene deposits in East and South Africa. Stable isotope analyses of tooth enamel from T. brumpti (4.02.5 Ma) and T. oswaldi (2.01.0 Ma) in Kenya show that the earliest Theropithecus at 4 Ma had a diet dominated by C4 resources. Progressively, this genus increased the proportion of C4-derived resources in its diet and by 1.0 Ma, had a diet that was nearly 100% C4-derived. It is likely that this diet was comprised of grasses or sedges; stable isotopes cannot, by themselves, give an indication of the relative importance of leaves, seeds, or underground storage organs to the diet of this primate. Theropithecus throughout the 4- to 1-Ma time range has a diet that is more C4-based than contemporaneous hominins of the genera Australopithecus, Kenyanthropus, and Homo; however, Theropithecus and Paranthropus have similar proportions of C4-based resources in their respective diets. PMID:23733967

Cerling, Thure E.; Chritz, Kendra L.; Jablonski, Nina G.; Leakey, Meave G.; Manthi, Fredrick Kyalo

2013-01-01

403

Burkitt lymphoma research in East Africa: highlights from the 9th African organization for research and training in cancer conference held in Durban, South Africa in 2013  

PubMed Central

A one-day workshop on Burkitt lymphoma (BL) was held at the 9th African Organization for Research and Training in Cancer (AORTIC) conference in 2013 in Durban, South Africa. The workshop featured 15 plenary talks by delegates representing 13 institutions that either fund or implement research on BL targeting AORTIC delegates primarily interested in pediatric oncology. The main outcomes of the meeting were improved sharing of knowledge and experience about ongoing epidemiologic BL research, BL treatment in different settings, the role of cancer registries in cancer research, and opportunities for African scientists to publish in scientific journals. The idea of forming a consortium of BL to improve coordination, information sharing, accelerate discovery, dissemination, and translation of knowledge and to build capacity, while reducing redundant efforts was discussed. Here, we summarize the presentations and discussions from the workshop.

2014-01-01

404

Emergence of rice yellow mottle virus in eastern Uganda: Recent and singular interplay between strains in East Africa and in Madagascar.  

PubMed

Epidemics of rice yellow mottle virus (RYMV) have developed recently in eastern Uganda, close to Lake Victoria in East Africa. Unexpectedly, all isolates from the affected area belonged to a single strain (named S4ug), a strain that is different from the S4lv strain that has been prevalent in the Lake Victoria basin for the past five decades. Interestingly, the S4ug strain is most closely related at the genomic level (except ORF1) to the strain present in Madagascar (S4mg), 2000km away. The minor parent of the S4mg recombinant strain could not be detected. Molecular clock dating analysis indicated that the singular sequence of events - that associated the emergence of a new strain (S4ug), a modular recombination between closely related strains (S4mg and S4ug) and a long distance transmission (S4mg) - occurred recently, within the past few decades. This finding is at variance with the process of gradual strain dispersal and diversification over two centuries throughout Africa that was previously established. PMID:25245592

Ochola, Dennis; Issaka, Souley; Rakotomalala, Mbolarinosy; Pinel-Galzi, Agns; Ndikumana, Innocent; Hubert, Judith; Hbrard, Eugnie; Sr, Yacouba; Tusiime, Geoffrey; Fargette, Denis

2015-01-01

405

Variability of vitamins B1, B2 and minerals content in baobab (Adansonia digitata) leaves in East and West Africa  

PubMed Central

The regional variability and ageage correlation on vitamin B1, vitamin B2 and minerals (Ca, Mg, P, K, Cu, Fe, Mn, Na, and Zn) concen