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Sample records for cameroon volcanic line

  1. Geohazards (floods and landslides in the Ndop plain, Cameroon volcanic line

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    Wotchoko Pierre

    2016-07-01

    Full Text Available The Ndop Plain, located along the Cameroon Volcanic Line (CVL, is a volcano-tectonic plain, formed by a series of tectonic movements, volcanic eruptions and sedimentation phases. Floods (annually and landslides (occasionally occur with devastating environmental effects. However, this plain attracts a lot of inhabitants owing to its fertile alluvial soils. With demographic explosion in the plain, the inhabitants (143,000 people tend to farm and inhabit new zones which are prone to these geohazards. In this paper, we use field observations, laboratory analyses, satellite imagery and complementary methods using appropriate software to establish hazard (flood and landslide maps of the Ndop Plain. Natural factors as well as anthropogenic factors are considered.

  2. A comparative review of petrogenetic processes beneath the Cameroon Volcanic Line: Geochemical constraints

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    Asobo N.E. Asaah

    2015-07-01

    Full Text Available The origin and petrogenesis of the Cameroon Volcanic Line (CVL, composed of volcanoes that form on both the ocean floor and the continental crust, are difficult to understand because of the diversity, heterogeneity, and nature of available data. Major and trace elements, and Sr-Nd-Pb isotope data of volcanic rocks of the CVL spanning four decades have been compiled to reinterpret their origin and petrogenesis. Volcanic rocks range from nephelinite, basanite and alkali basalts to phonolite, trachyte and rhyolite with the presence of a compositional gap between SiO2 58–64 wt.%. Similarities in geochemical characteristics, modeled results for two component mixing, and the existence of mantle xenoliths in most mafic rocks argue against significant crustal contamination. Major and trace element evidences indicate that the melting of mantle rocks to generate the CVL magma occurred dominantly in the garnet lherzolite stability field. Melting models suggest small degree (<3% partial melting of mantle bearing (6–10% garnet for Mt. Etinde, the Ngaoundere Plateau and the Biu Plateau, and <5% of garnet for the oceanic sector of the CVL, Mt. Cameroon, Mt. Bambouto, Mt. Manengouba and the Oku Volcanic Group. The Sr-Nd-Pb isotope systematics suggest that mixing in various proportions of Depleted MORB Mantle (DMM with enriched mantle 1 and 2 (EM1 and EM2 could account for the complex isotopic characteristics of the CVL lavas. Low Mg number (Mg# = 100 × MgO/(MgO + FeO and Ni, Cr and Co contents of the CVL mafic lavas reveal their crystallization from fractionated melts. The absence of systematic variation in Nb/Ta and Zr/Hf ratios, and Sr-Nd isotope compositions between the mafic and felsic lavas indicates progressive evolution of magmas by fractional crystallization. Trace element ratios and their plots corroborate mantle heterogeneity and reveal distinct geochemical signatures for individual the CVL volcanoes.

  3. A comparative review of petrogenetic processes beneath the Cameroon Volcanic Line:Geochemical constraints

    Institute of Scientific and Technical Information of China (English)

    Asobo N.E. Asaah; Tetsuya Yokoyama; Festus T. Aka; Tomohiro Usui; Mengnjo J. Wirmvem; Boris Chako Tchamabe; Takeshi Ohba; Gregory Tanyileke; J.V. Hell

    2015-01-01

    The origin and petrogenesis of the Cameroon Volcanic Line (CVL), composed of volcanoes that form on both the ocean floor and the continental crust, are difficult to understand because of the diversity, het-erogeneity, and nature of available data. Major and trace elements, and Sr-Nd-Pb isotope data of volcanic rocks of the CVL spanning four decades have been compiled to reinterpret their origin and petrogenesis. Volcanic rocks range from nephelinite, basanite and alkali basalts to phonolite, trachyte and rhyolite with the presence of a compositional gap between SiO2 58e64 wt.%. Similarities in geochemical characteristics, modeled results for two component mixing, and the existence of mantle xenoliths in most mafic rocks argue against significant crustal contamination. Major and trace element evidences indicate that the melting of mantle rocks to generate the CVL magma occurred dominantly in the garnet lherzolite stability field. Melting models suggest small degree (<3%) partial melting of mantle bearing (6e10%) garnet for Mt. Etinde, the Ngaoundere Plateau and the Biu Plateau, and<5%of garnet for the oceanic sector of the CVL, Mt. Cameroon, Mt. Bambouto, Mt. Manengouba and the Oku Volcanic Group. The Sr-Nd-Pb isotope sys-tematics suggest that mixing in various proportions of Depleted MORB Mantle (DMM) with enriched mantle 1 and 2 (EM1 and EM2) could account for the complex isotopic characteristics of the CVL lavas. Low Mg number (Mg# ¼ 100 ? MgO/(MgO þ FeO)) and Ni, Cr and Co contents of the CVL mafic lavas reveal their crystallization from fractionated melts. The absence of systematic variation in Nb/Ta and Zr/Hf ratios, and Sr-Nd isotope compositions between the mafic and felsic lavas indicates progressive evolution of magmas by fractional crystallization. Trace element ratios and their plots corroborate mantle het-erogeneity and reveal distinct geochemical signatures for individual the CVL volcanoes.

  4. Late Cretaceous intraplate silicic volcanic rocks from the Lake Chad region: An extension of the Cameroon volcanic line?

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    Shellnutt, J. G.; Lee, T.-Y.; Torng, P.-K.; Yang, C.-C.; Lee, Y.-H.

    2016-07-01

    Silicic volcanic rocks at Hadjer el Khamis, near Lake Chad, are considered to be an extension of the Cameroon volcanic line (CVL) but their petrogenetic association is uncertain. The silicic rocks are divided into peraluminous and peralkaline groups with both rock types chemically similar to within-plate granitoids. In situ U/Pb zircon dating yielded a mean 206Pb/238U age of 74.4 ± 1.3 Ma indicating the magmas erupted ˜10 million years before the next oldest CVL rocks (i.e., ˜66 Ma). The Sr isotopes (i.e., ISr = 0.7021-0.7037) show a relatively wide range but the Nd isotopes (i.e., 143Nd/144Ndi = 0.51268-0.51271) are uniform and indicate that the rocks were derived from a moderately depleted mantle source. Thermodynamic modeling shows that the silicic rocks likely formed by fractional crystallization of a mafic parental magma but that the peraluminous rocks were affected by low temperature alteration processes. The silicic rocks are more isotopically similar to Late Cretaceous basalts identified within the Late Cretaceous basins (i.e., 143Nd/144Ndi = 0.51245-0.51285) of Chad than the uncontaminated CVL rocks (i.e., 143Nd/144Ndi = 0.51270-0.51300). The age and isotopic compositions suggest the silicic volcanic rocks of the Lake Chad region are related to Late Cretaceous extensional volcanism in the Termit basin. It is unlikely that the silicic volcanic rocks are petrogenetically related to the CVL but it is possible that magmatism was structurally controlled by suture zones that formed during the opening of the Central Atlantic Ocean and/or the Pan-African Orogeny.

  5. Geohazards (floods and landslides) in the Ndop plain, Cameroon volcanic line

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    Wotchoko, Pierre; Bardintzeff, Jacques-Marie; Itiga, Zénon; Nkouathio, David Guimolaire; Guedjeo, Christian Suh; Ngnoupeck, Gerald; Dongmo, Armand Kagou; Wandji, Pierre

    2016-07-01

    The Ndop Plain, located along the Cameroon Volcanic Line (CVL), is a volcano-tectonic plain, formed by a series of tectonic movements, volcanic eruptions and sedimentation phases. Floods (annually) and landslides (occasionally) occur with devastating environmental effects. However, this plain attracts a lot of inhabitants owing to its fertile alluvial soils. With demographic explosion in the plain, the inhabitants (143,000 people) tend to farm and inhabit new zones which are prone to these geohazards. In this paper, we use field observations, laboratory analyses, satellite imagery and complementary methods using appropriate software to establish hazard (flood and landslide) maps of the Ndop Plain. Natural factors as well as anthropogenic factors are considered. The hazard maps revealed that 25% of the area is exposed to flood hazard (13% exposed to high flood hazard, 12% to moderate) and 5% of the area is exposed to landslide hazard (2% exposed to high landslide hazard, 3% to moderate). Some mitigation measures for floods (building of artificial levees, raising foundations of buildings and the meticulous regulation of the flood guards at Bamendjing Dam) and landslides (slope terracing, planting of trees, and building retaining walls) are proposed.

  6. Chemistry and origin of the Mayo Kila sapphires, NW region Cameroon (Central Africa): Their possible relationship with the Cameroon volcanic line

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    Paul Mbih, Kemeng; Meffre, Sebastien; Yongue, Rose Fouateu; Kanouo, Nguo Sylvestre; Jay, Thomson

    2016-06-01

    Mineralogical, chemical and geochronological studies constrained the origin of sapphires from Mayo Kila, Northwest Cameroon. The sapphires are mostly blue, with sizes ranging from 2 to 5 mm. The pale blue grains are transparent, whereas, other corundums are transparent to translucent and/or opaque. The sapphires are dominantly euhedral to sub-hedral with few polished lustrous grains, acquired features during moderate to short distance transport from a proximal source rock. Solid inclusions are limited to rutile and zircon. Trace element analysis of sapphires shows significant concentration (in ppm) in some elements: Fe (2208-14,473), Ti (82-1783), Ga (77-512), Mg (0.9-264.9), Cr (b.d.l -168) and V (1.3-82). The other elements (e.g. Sn, Nb, Ta, Th, Zr, Ni, Ce) are generally below 10 ppm. The calculated ratios for some of the selected elements show an extreme variation: Fe/Mg (43-3043), Fe/Ti (2-76), Ti/Mg (1-328), and Ga/Mg (0.4-363). They are dominantly corundum crystallized in alkaline magma (s) with few from metamorphic source (s). Trace elemental features with Hf (13,354-26,238 ppm), Th (4018-45,584 ppm) and U (7825-17,175 ppm), and Th/U (0.39-2.65) found in zircon inclusions are compatible with quantified values in magmatic crystallized zircons. The Cenozoic age (mean of 30.78 ± 0.28 Ma) obtained for zircon inclusions is close to the age of some igneous rocks found within the Cameroon Volcanic Line (e.g. rocks of the Mount Oku: 31-22 Ma), showing the same period of formation. The most probable source of the zircon host sapphires is the Oku Mountain located SW of Mayo Kila.

  7. Gas emission from diffuse degassing structures (DDS) of the Cameroon volcanic line (CVL): Implications for the prevention of CO2-related hazards

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    Issa; Ohba, T.; Chako Tchamabé, B.; Padrón, E.; Hernández, P.; Eneke Takem, E. G.; Barrancos, J.; Sighomnoun, D.; Ooki, S.; Nkamdjou, Sigha; Kusakabe, M.; Yoshida, Y.; Dionis, S.

    2014-08-01

    In the mid-1980s, lakes Nyos and Monoun violently released massive gas, mainly magmatic CO2 killing about 1800 people. Subsequent geochemical surveys and social studies indicate that lakes Nyos and Monoun event is cyclic in nature and may occur anywhere in the about 37 other volcanic lakes located in the corridor of the Cameroon volcanic line (CVL). This potential threat motivated us to check if, alike Nyos and Monoun, the internal dynamic of the other lakes is also controlled by inputs of deep-seated-derived CO2 and attempt to measure and provide comprehensive insights on the passive gas emission along the CVL. This knowledge shall contribute to the prevention of volcanic lake-related hazards in Cameroon and the refinement of the Global Carbon Cycle. We used in situ fixation and dry gas phase sampling methods to determine CO2 origin and the concentration, and the accumulation chamber technique to measure diffuse CO2 emission from nine lakes and on soil at Nyos Valley and Mount Manenguba Caldera. The results suggest that, although in minor concentrations (compared to Nyos and Monoun), ranging from 0.56 mmol kg- 1 to 8.75 mmol kg- 1, the bottom waters of some lakes also contain measurable magmatic CO2 with δ13C varies from - 4.42‰ to - 9.16‰ vs. PDB. That finding implies that, under certain circumstances, e.g. increase to volcanic and/or tectonic activities along the CVL, the concerned lakes could develop a Nyos-type behavioural scheme. The diffuse gas emission results indicate that the nine surveyed lakes release approximately 3.69 ± 0.37 kt km- 2 yr- 1 of CO2 to the atmosphere; extrapolation to the approximately 39 volcanic lakes located on the CVL yields an approximate CO2 output of 27.37 ± 0.5 kt km- 2 yr- 1, representing 0.023% of the global CO2 output from volcanic lakes. In addition to the precedent value, the gas removal operation in lakes Nyos and Monoun released approximately 2.52 ± 0.46 × 108 mol km- 2 yr- 1 CO2 to the atmosphere from January

  8. Typology of Natural Hazards and Assessment of Associated Risks in the Mount Bambouto Caldera (Cameroon Line, West Cameroon)

    Institute of Scientific and Technical Information of China (English)

    Ghislain T. ZANGMO; Armand D. KAGOU; David G. NKOUATHIO; Pierre WANDJI

    2009-01-01

    Mount Bambouto is a polygenic stratovoicano of the Cameroon Volcanic Line, built between 21 Ma and 4.5 Ma. It is situated approximately 200 km NE of Mount Cameroon, between 09°55' and 10°15' longitude east and, 05°25' and 05°50' latitude north. The volcano covers an area of (13×8 km). Mount Bambouto is characterized by several natural hazards of different origins: meteorological, such as landslides and rock falls; anthropogenic, such as bushfires, tribal wars and deforestation; and volcanological, such as volcanic eruption. The thematic map shows that 55-60% of the caldera has high probability of occurrence of mass movement. The caldera has a high population density (3000 inhabitants), which increases the level of risk, evaluated at approximately $US3.8 million for patrimony, 3000 civilian deaths and destruction of biodiversity.

  9. Evaluation of groundwater quality and its suitability for drinking, domestic, and agricultural uses in the Banana Plain (Mbanga, Njombe, Penja) of the Cameroon Volcanic Line.

    Science.gov (United States)

    Ako, Andrew Ako; Shimada, Jun; Hosono, Takahiro; Ichiyanagi, Kimpei; Nkeng, George Elambo; Fantong, Wilson Yetoh; Eyong, Gloria Eneke Takem; Roger, Ntankouo Njila

    2011-12-01

    Groundwater quality of the Banana Plain (Mbanga, Njombe, Penja-Cameroon) was assessed for its suitability for drinking, domestic, and agricultural uses. A total of 67 groundwater samples were collected from open wells, springs, and boreholes. Samples were analyzed for physicochemical properties, major ions, and dissolved silica. In 95% of groundwater samples, calcium is the dominant cation, while sodium dominates in 5% of the samples. Eighty percent of the samples have HCO(3) as major anion, and in 20%, NO(3) is the major anion. Main water types in the study area are CaHCO(3), CaMgHCO(3), CaNaHCO(3), and CaNaNO(3)ClHCO(3). CO(2)-driven weathering of silicate minerals followed by cation exchange seemingly controls largely the concentrations of major ions in the groundwaters of this area. Nitrate, sulfate, and chloride concentrations strongly express the impact of anthropogenic activities (agriculture and domestic activities) on groundwater quality. Sixty-four percent of the waters have nitrate concentrations higher than the drinking water limit. Also limiting groundwater use for potable and domestic purposes are contents of Ca(2+), Mg(2+) and HCO(3) (-) and total hardness (TH) that exceed World Health Organization (WHO) standards. Irrigational suitability of groundwaters in the study area was also evaluated, and results show that all the samples are fit for irrigation. Groundwater quality in the Banana Plain is impeded by natural geology and anthropogenic activities, and proper groundwater management strategies are necessary to protect sustainably this valuable resource.

  10. Cameroon.

    Science.gov (United States)

    1992-06-01

    The US profile of Cameroon indicates brief statistics on the population, geography, government, and economy and brief descriptions of the population, the history, government, political conditions, the economy, foreign relations, defense, and relations with the US. Principal government and US officials are furnished. The 1991 estimated population of Cameroon was 11.7 million of which 60% is rural. There are 200 different tribes who speak many African languages and dialects. The French and English languages both have official status. Muslims live in the north and Christians in the south. 80% live in the formerly French east. The growth rate is 3%. There is 65% literacy. Infant mortality is 20%. 70% are agricultural workers, 13% industrial and commercial, and 17% other. The government is an independent republic with an executive and legislative branch. Independence was achieved in 1960. There is 1 ruling party. Traditional courts administer the laws. Traditional rulers are treated as administrative adjuncts. Suffrage is universal adult. The central government budget is 1.4 billion of which 8.7% is for defense. There are 10 provinces and 4 major cities. The seaport city Douala is the largest at 1.5 million. Gross domestic product (GDP) is $12.5 billion with an annual growth rate of 4.3% and an inflation rate of 2%. Growth has been variable since 1988 and reached a low of 2.4% in 1988-89. Oil, natural gas, bauxite, iron core, and timber are natural resources. 27% of the GDP is in agricultural products (cocoa, coffee, cotton, fishing, and forestry). 13% of the GDP is manufacturing and 24% is industry. Exports are valued at $2.9 billion and imports at $2.2 billion. Major markets are France, Netherlands, and the US. Imports include intermediate goods, capital goods, fuel and lubricants, foodstuffs, beverages, and tobacco. Early inhabitants were the Pygmies, followed later by Bantu speakers, and Muslim Fulani. Political consolidation was achieved in 1970 after a period of

  11. Geochemistry of the volcanic rocks from Bioko Island (“Cameroon Hot Line”: Evidence for plume-lithosphere interaction

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    Fadimatou Ngounouno Yamgouot

    2016-09-01

    Full Text Available Bioko Island (3008 m a.s.l is located in the presently more active volcanic zone of the Cameroon Line and composed essentially of alkaline basalts and hawaiites, and lesser mugearites. The rocks show microlitic porphyritic texture with phenocrysts of olivine (83% < Fo < 87% and clinopyroxene in a matrix of plagioclase, clinopyroxene and oxides. Hawaiites and mugearites also include phenocrysts of plagioclase (An62-67Ab35-32Or3-1. Major element variation diagrams show an increase in SiO2, Al2O3, Na2O and K2O with increasing MgO for the studied rock groups. The rocks are characterized by low (86Sr/87Sri ratios (0.70320–0.70406, high ɛNd(t values (2.56–4.33 and high (206Pb/204Pbi ratios (20.032–20.035 values. Basalts are enriched in LILE and LREE, and have (Hf/SmN = 0.57–1.16. These geochemical signatures are similar to those of the Mount Cameroon rocks, and might be attributed to low degrees of partial melting from a garnet-amphibole-bearing mantle source. The trace elements and isotopic compositions suggest that the parental magma source might have involved HIMU- and EM1-components.

  12. Potential and limitations of risk scenario tools in volcanic areas through an example at Mount Cameroon

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    P. Gehl

    2013-10-01

    Full Text Available This paper presents an integrated approach to conduct a scenario-based volcanic risk assessment on a variety of exposed assets, such as residential buildings, cultivated areas, network infrastructures or individual strategic buildings. The focus is put on the simulation of scenarios, based on deterministic adverse event input, which are applied to the case study of an effusive eruption on the Mount Cameroon volcano, resulting in the damage estimation of the assets located in the area. The work is based on the recent advances in the field of seismic risk. A software for systemic risk scenario analysis developed within the FP7 project SYNER-G has been adapted to address the issue of volcanic risk. Most significant improvements include the addition of vulnerability models adapted to each kind of exposed element and the possibility to quantify the successive potential damages inflicted by a sequence of adverse events (e.g. lava flows, tephra fall, etc.. The use of an object-oriented architecture gives the opportunity to model and compute the physical damage of very disparate types of infrastructures under the same framework. Finally, while the risk scenario approach is limited to the assessment of the physical impact of adverse events, a specific focus on strategic infrastructures and a dialogue with stakeholders helps in evaluating the potential wider indirect consequences of an eruption.

  13. Locating the depth of magma supply for volcanic eruptions, insights from Mt. Cameroon.

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    Geiger, Harri; Barker, Abigail K; Troll, Valentin R

    2016-10-07

    Mt. Cameroon is one of the most active volcanoes in Africa and poses a possible threat to about half a million people in the area, yet knowledge of the volcano's underlying magma supply system is sparse. To characterize Mt. Cameroon's magma plumbing system, we employed mineral-melt equilibrium thermobarometry on the products of the volcano's two most recent eruptions of 1999 and 2000. Our results suggest pre-eruptive magma storage between 20 and 39 km beneath Mt. Cameroon, which corresponds to the Moho level and below. Additionally, the 1999 eruption products reveal several shallow magma pockets between 3 and 12 km depth, which are not detected in the 2000 lavas. This implies that small-volume magma batches actively migrate through the plumbing system during repose intervals. Evolving and migrating magma parcels potentially cause temporary unrest and short-lived explosive outbursts, and may be remobilized during major eruptions that are fed from sub-Moho magma reservoirs.

  14. Locating the depth of magma supply for volcanic eruptions, insights from Mt. Cameroon

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    Geiger, Harri; Barker, Abigail K.; Troll, Valentin R.

    2016-01-01

    Mt. Cameroon is one of the most active volcanoes in Africa and poses a possible threat to about half a million people in the area, yet knowledge of the volcano’s underlying magma supply system is sparse. To characterize Mt. Cameroon’s magma plumbing system, we employed mineral-melt equilibrium thermobarometry on the products of the volcano’s two most recent eruptions of 1999 and 2000. Our results suggest pre-eruptive magma storage between 20 and 39 km beneath Mt. Cameroon, which corresponds to the Moho level and below. Additionally, the 1999 eruption products reveal several shallow magma pockets between 3 and 12 km depth, which are not detected in the 2000 lavas. This implies that small-volume magma batches actively migrate through the plumbing system during repose intervals. Evolving and migrating magma parcels potentially cause temporary unrest and short-lived explosive outbursts, and may be remobilized during major eruptions that are fed from sub-Moho magma reservoirs. PMID:27713494

  15. Lithostratigraphy, volcanism, paleomagnetism and palynology of Quaternary lacustrine deposits from Barombi Mbo (West Cameroon): Preliminary results

    Science.gov (United States)

    Maley, J.; Livingstone, D. A.; Giresse, P.; Thouveny, N.; Brenac, P.; Kelts, K.; Kling, G.; Stager, C.; Haag, M.; Fournier, M.; Bandet, Y.; Williamson, D.; Zogning, A.

    1990-08-01

    We present preliminary results from the study of 23.50-m core from Lake Barombi Mbo, representing the last 25,000 years. The lake is in an explosion crater formed during Quaternary time. The very laminated sediment is composed mostly of clay containing 5-10% organic carbon. Each couplet is commonly composed of a basal lamina rich in quartz, plant debris, muscovite and sponge spicules, and of a more clayey upper lamina often with siderite. A perturbed section near the base of the core, before ca. 21,000 yr B.P., could be the result of a violent release of gas, such CO 2, comparable to the recent Nyos gas eruption. The paleomagnetic studies exhibit high-frequency oscillations interpreted as paleosecular variations of the local geomagnetic field. This first record obtained on the African continent can be closely compared to the type record obtained in Western Europe. The pollen results demonstrate the presence of a forest refuge in West Cameroon during the last great arid period, ca. 18,000 yr B.P. When equatorial forest was broken up, elements of montane vegetation spread to the lowlands. These phenomena resulted from a drying and cooling climate.

  16. Structure of the Crust beneath Cameroon, West Africa, from the Joint Inversion of Rayleigh Wave Group Velocities and Receiver Functions

    Energy Technology Data Exchange (ETDEWEB)

    Tokam, A K; Tabod, C T; Nyblade, A A; Julia, J; Wiens, D A; Pasyanos, M E

    2010-02-18

    The Cameroon Volcanic Line (CVL) is a major geologic feature that cuts across Cameroon from the south west to the north east. It is a unique volcanic lineament which has both an oceanic and a continental sector and consists of a chain of Tertiary to Recent, generally alkaline volcanoes stretching from the Atlantic island of Pagalu to the interior of the African continent. The oceanic sector includes the islands of Bioko (formerly Fernando Po) and Sao Tome and Principe while the continental sector includes the Etinde, Cameroon, Manengouba, Bamboutos, Oku and Mandara mountains, as well as the Adamawa and Biu Plateaus. In addition to the CVL, three other major tectonic features characterize the region: the Benue Trough located northwest of the CVL, the Central African Shear Zone (CASZ), trending N70 degrees E, roughly parallel to the CVL, and the Congo Craton in southern Cameroon. The origin of the CVL is still the subject of considerable debate, with both plume and non-plume models invoked by many authors (e.g., Deruelle et al., 2007; Ngako et al, 2006; Ritsema and Allen, 2003; Burke, 2001; Ebinger and Sleep, 1998; Lee et al, 1994; Dorbath et al., 1986; Fairhead and Binks, 1991; King and Ritsema, 2000; Reusch et al., 2010). Crustal structure beneath Cameroon has been investigated previously using active (Stuart et al, 1985) and passive (Dorbath et al., 1986; Tabod, 1991; Tabod et al, 1992; Plomerova et al, 1993) source seismic data, revealing a crust about 33 km thick at the south-western end of the continental portion of the CVL (Tabod, 1991) and the Adamawa Plateau, and thinner crust (23 km thick) beneath the Garoua Rift in the north (Stuart et al, 1985) (Figure 1). Estimates of crustal thickness obtained using gravity data show similar variations between the Garoua rift, Adamawa Plateau, and southern part of the CVL (Poudjom et al., 1995; Nnange et al., 2000). In this study, we investigate further crustal structure beneath the CVL and the adjacent regions in

  17. The origin of the Line Islands: plate or plume controlled volcanism?

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    Storm, L. P.; Konter, J. G.; Koppers, A. A.

    2011-12-01

    Geochemical compositions of melts produced in the Earth's mantle provide key data for our understanding of the Earth's internal structure. Particularly, the range in compositions for oceanic intraplate volcanism has fueled the ongoing debate on the dynamic origin of hotspots. Traditionally, hotspots have been interpreted to originate from narrow, upwelling plumes of hot mantle material that reach the bottom of the tectonic plates. Progressively younger volcanoes, as seen at, for example, Hawaii, are then derived from plume melts. However, such a plume may originate from the core-mantle boundary, the top of seismically defined superplumes, or the origin may not lie in a buoyantly upwelling plume at all. The presence of an age progressive volcanic chain and a large igneous province, a high buoyancy flux, the geochemical composition of the erupted lavas, and seismically slow velocities have been used to distinguish different hotspot origins. Volcanic chains that lack most of these features may originate from the eruption of shallow melts along lithospherically controlled cracks. A unique area to study this type of volcanism is the Line Islands. These islands define a complex chain of volcanoes south of Hawaii that morphologically define multiple sub-groups. Moreover, recent age dating has revealed a complex geochronology. Combined geochronological and geochemical data from the Line Islands allude to the presence of shallow mantle melts that feed eruptions where there are weaknesses in the plates due to fractures or fissures. The Line Islands consist of elongated ridges, seamounts, atolls and islands that form the northern segment of the Line-Tuamotu chain of volcanoes. The volcanic chain is divided into three morphologically distinct regions; the northern, central and southern provinces. Long en echelon ridges of the Line Islands Cross Trend intersect the northern province at 14-16°N, which consists of the section between the Molokai and Clarion fracture zones. The

  18. The late holocene palaeoenvironment in the Lake Njupi area, west Cameroon: implications regarding the history of Lake Nyos

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    Zogning, Appolinaire; Giresse, Pierre; Maley, Jean; Gadel, François

    1997-04-01

    Lake Njupi, 1 km east of Lake Nyos, on the Cameroon Volcanic Line, was formed by the damming of a local crustal depression. Two cores from Lake Nyos were analysed which penetrated sediments at the margin of the lake. The older deposits give an age of 3400 years BP and this date is proposed as a minimum age for Lake Njupi. Sedimentological, palynological and geochemical studies of a 2 m section provide an opportunity to reconstruct the Late Holocene environmental history. It is an organic-rich deposit (organic carbon up to 30%) with an abundant Silicospongia spicules fraction. An obvious sedimentary homogeneity is interrupted by 5 fine to coarse layers with sandy quartz and lignitic remains. Such inputs were denoted by carbohydrate maxima or sometimes by phenolic compounds. This study confirms the evidence of an arid period culminating between 2500 and 2000 yrs BP. This crisis began around 3000 yrs BP in the rain forest area of West Cameroon and also further to the south in Congo. Lake Njupi, situated today in a mostly grassland savanna environment known as the "Grass Fields", provides evidence for environmental changes from a mosaic of forest and savanna before 2500 years BP to a savanna characterised by high grass pollen contents (75 to 85%), with small islands of forest. The mountain vegetation characterised by Podocarpus and Olea capensis retreated around 2300 years BP at the time Elaeis guineensis (the Oil Palm) began its extension as a pioneer tree, later providing opportunities for its domestication by man.

  19. A new Xylaria (Xylariaceae, Ascomycota) from Cameroon

    DEFF Research Database (Denmark)

    Læssøe, Thomas; Cheek, M.

    2002-01-01

    A new species of Xylaria (Xylariaceae, Ascomycota) from western Cameroon is described on teleomorphic and cultural characters.......A new species of Xylaria (Xylariaceae, Ascomycota) from western Cameroon is described on teleomorphic and cultural characters....

  20. The Language Question in Cameroon

    Directory of Open Access Journals (Sweden)

    Echu, George

    2004-01-01

    Full Text Available In multilingual Cameroon, 247 indigenous languages live side by side with English and French (the two official languages and Cameroon Pidgin English (the main lingua franca. While the two official languages of colonial heritage dominate public life in the areas of education, administration, politics, mass media, publicity and literature, both the indigenous languages and Cameroon Pidgin English are relegated to the background. This paper is a critique of language policy in Cameroon revealing that mother tongue education in the early years of primary education remains a distant cry, as the possible introduction of an indigenous language in the school system is not only considered unwanted by educational authorities but equally combated against by parents who believe that the future of their children lies in the mastery of the official languages. This persistent disregard of indigenous languages does not only alienate the Cameroonian child culturally, but further alienates the vast majority of Cameroonians who are illiterate (in English and French since important State business is carried out in the official languages. As regards the implementation of the policy of official language bilingualism, there is clear imbalance in the use of the two official languages as French continues to be the dominant official language while English is relegated to a second place within the State. The frustration that ensues within the Anglophone community has led in recent years to the birth of Anglophone nationalism, a situation that seems to be widening the rift between the two main components of the society (Anglophones and Francophones, thereby compromising national unity. The paper is divided into five major parts. After a brief presentation of the country, the author dwells on multilingualism and language policy since the colonial period. The third, fourth and last parts of the paper focus on the critique of language policy in Cameroon with emphasis first on

  1. Variation in stable isotope ratios of monthly rainfall in the Douala and Yaounde cities, Cameroon: local meteoric lines and relationship to regional precipitation cycle

    Science.gov (United States)

    Wirmvem, Mengnjo Jude; Ohba, Takeshi; Kamtchueng, Brice Tchakam; Taylor, Eldred Tunde; Fantong, Wilson Yetoh; Ako, Ako Andrew

    2016-04-01

    Hydrogen (D) and oxygen (18O) stable isotopes in precipitation are useful tools in groundwater recharge and climatological investigations. This study investigated the isotopes in rainfall during the 2013 and 2014 hydrological years in the Douala and Yaounde urban cities. The objectives were to generate local meteoric water lines (LMWLs), define the spatial-temporal variations of the isotopes in rainwater and their relationship to the regional precipitation cycle, and determine the factors controlling the isotopic variation. The LWMLs in Douala and Yaounde were δD = 7.92δ18O + 12.99 and δD = 8.35δ18O + 15.29, respectively. The slopes indicate isotopic equilibrium conditions during rain formation and negligible evaporation effect during rainfall. Precipitation showed similar wide ranges in δ18O values from -5.26 to -0.75 ‰ in Douala and -5.8 to +1.81 ‰ in Yaounde suggesting a common moisture source from the Atlantic Ocean. Enriched weighted mean δ18O (wδ18O) values during the low pre- and post-monsoon showers coincided with low convective activity across the entire region. Enriched isotopic signatures also marked the West African monsoon transition phase during each hydrological year. Abrupt wδ18O depletion after the transition coincided with the monsoon onset in the region. Peak periods of monsoonal rainfall, associated with high convective activities, were characterised by the most depleted wδ18O values. Controls on isotopic variations are the amount effect and moisture recycling. The stable isotope data provide a tool for groundwater recharge studies while the isotopic correlation with regional rainfall cycle demonstrate their use as markers of moisture circulation and detecting climatic changes in precipitation.

  2. Leadership Style: School Perspective in Cameroon

    Directory of Open Access Journals (Sweden)

    Asan Vernyuy Wirba

    2015-01-01

    Full Text Available This paper examines leadership styles of secondary school principals in Cameroon, in terms of transformational, transactional, and laissez-faire leadership styles. This paper discusses the leadership styles in Cameroon and puts forward ideas for continuous improvement. A qualitative approach, using a semistructured interview, was adopted. It was conducted on ten principals, ten teachers, and ten students. Majority of respondents from schools described their principals as transformational leaders. Doubts are cast on the nature of transformational leadership in schools in Cameroon, since there is less training and development for leadership in schools.

  3. CPAFFC Delegation Visits Sierra Leone and Cameroon

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    <正>At the invitation of the Sierra Leone-China Friendship Association (SLCFA) and the Ministry of Territorial Administration and Decentralization of Cameroon, a 14-member CPAFFC delegation headed by Wang Daoyu, vice chairman of the Standing Committee of the Shandong Provincial People’s Congress, paid a goodwill visit to Sierra Leone and Cameroon in early December 2005. In Sierra Leone Vice President Solomon Ekuma Berewa, President of the Parliament Edmond Cowan, and Vice Foreign Minister Mohamed Kamara, and in

  4. Magnetic fabrics of the Miocene ignimbrites from West-Cameroon: Implications for pyroclastic flow source and sedimentation

    Science.gov (United States)

    Gountié Dedzo, M.; Nédélec, A.; Nono, A.; Njanko, T.; Font, E.; Kamgang, P.; Njonfang, E.; Launeau, P.

    2011-06-01

    The Miocene ignimbrites of Mounts Bambouto and Bamenda located in the central part of Cameroon Volcanic Line are generally made of welded and non-welded massive lapilli tuff and lithic breccias. These discontinuous deposits cover a total area of 180 km 2 with thickness ranging from 25 to 200 m. The different facies contain several lithic fragments of mainly trachytic nature. The devitrified matrix of the welded ignimbrites is constituted by sanidine, anorthoclase, quartz, plagioclase, clinopyroxene, biotite, Fe-Ti oxides and devitrified fiammes. Anisotropy of magnetic susceptibility (AMS) is used to characterize magnetic fabrics and to provide an estimate of flow direction of each ignimbrite sheet. Magnetic mineralogy results from different flow units show that titanomagnetite, titanohematite, maghemite and goethite with grain size ranging from coarse MD to very fine SP are the main magnetic carriers of these ignimbrites. Inferred transport directions based on the AMS data and field indicators show that Bambouto caldera is the source of main pyroclastic deposits of Mount Bambouto. In southwestern Mount Bamenda, Santa-Mbu caldera or Bambouto caldera constituted the probable emission center of Mbengwi, Bamenda and Mbu ignimbrite sheets, whereas magnetic fabrics of Bambili, Sabga and Big Babanki ignimbrites demonstrate that these deposits were emitted from a northeastern source, namely Oku vent in Mount Oku. A small number of subvertical AMS fabrics correspond to rocks possibly modified by an elutriation process.

  5. Survey of tomato diseases in Cameroon

    Directory of Open Access Journals (Sweden)

    Fontem, DA.

    1993-01-01

    Full Text Available Tomato (Lycopersicon esculentum Mill. is the most widely cultivated field vegetable crop in Cameroon. On-farm surveys were undertaken from November 1988 to October 1991 to identify nursery and field diseases in major tomato producing areas of Cameroon, Damping-off and seedling blights were the main seedling diseases. Of the eleven diseases observed in the field, the most widely distributed and severe on the foliage and fruits were early (Alternaria solani and late (Phytophthora infestans blights. Late blight was the most severe disease in the wet season while early blight was most severe in the dry season. Nine pathogens were associated with various fruit rots. This study indicates the need for an identification of appropriate control methods for early and late blights of tomato in Cameroon.

  6. The Burden of Orphans and Vulnerable Children Due to HIV/AIDS in Cameroon.

    Science.gov (United States)

    Nsagha, Dickson S; Bissek, Anne-Cécile Zk; Nsagha, Sarah M; Assob, Jules-Clement N; Kamga, Henri-Lucien F; Njamnshi, Dora M; Njunda, Anna L; Obama, Marie-Thérèse O; Njamnshi, Alfred K

    2012-01-01

    means of support. Similarly, the death of many people in their prime working years hamper the economy. Businesses are adversely affected due to the need to recruit and train new staff. Health and social service systems suffer from the loss of health workers, teachers, and other skilled workers. OVC due to HIV/AIDS are a major public health problem in Cameroon as the HIV prevalence continues its relentless increase with 141 new infections per day. In partnership with the Ministry of Social Affairs and other development organizations, the Ministry of Public Health has been striving hard to provide for the educational and medical needs of the OVC, vocational training for the out-of- school OVC and income generating activities for foster families and families headed by children. A continous multi-sectorial approach headed by the government to solve the problem of OVC due to AIDS is very important. In line with the foregoing, recommendations are proposed for the way forward.

  7. Homosexuality in Cameroon: identity and persecution

    NARCIS (Netherlands)

    Geschiere, P.; Dubel, I.; Hielkema, A.

    2010-01-01

    What does it mean to come out of the closet in Cameroon? It is clear that it takes courage, particularly lately, as the law has always expressly prohibited homosexuality. (1) The police, generally feared because of their brutal extortion of money from people, are eager to react to accusations of 'im

  8. The Reception of American Literature in Cameroon

    Science.gov (United States)

    Djockoua, Manyaka Toko

    2014-01-01

    In Cameroon, popular belief associates American literature with its country's economic and political greatness. Yet, if millions of Cameroonians show a growing enthusiasm for a visit to the US, just a few are interested in learning its literature. Using theories on the reading and teaching of literature, statistical data based on a questionnaire,…

  9. State formation, religion, and land tenure in Cameroon

    NARCIS (Netherlands)

    Schilder, K.; African Studies Centre, Leiden

    1988-01-01

    The purpose of this analytical bibliography is to provide an overview of the recently published social science literature on State formation, religion, and land tenure in Cameroon. The 800 entries have been arranged under the following subject headings: The Cameroon State (nation building, political

  10. Pedagogic Implications of Regionally-Determined Varieties of Cameroon English

    Science.gov (United States)

    Ubanako, Valentine Njende

    2011-01-01

    With much regional variation in Cameroon English, language learning and teaching becomes very much affected in Cameroon. As the same users make use of the various forms of English as the changing circumstances require, it becomes more and more difficult for them to make clear distinctions between the varieties, and somehow all of these varieties…

  11. An approach for the evaluation of rural governance in Cameroon: are community forests really forests for the communities?

    Directory of Open Access Journals (Sweden)

    Hilaire NKENGFACK

    2009-01-01

    Full Text Available The aim of this paper is to evaluate the contribution of the traditionalexploitation of timber, in a community framework, to the respect of governanceprinciples in actions for the fight against poverty in some rural communities inCameroon. In 1990, the government of Cameroon adopted laws on the freedomof association that authorised teaming up for the search of possibilities for abetter economic welfare of populations. It is in line with this that in 1994, a newforest law which authorises willing communities to organise themselves andrequest the government to grant them a portion of the national forest of thepublic domain to be managed by them and for their personal interest. Also, andwith the help of the international community, Cameroon elaborated in 1998 itsfirst poverty reduction strategy paper that encouraged amongst others,community actions in the search of solutions to the economic crisis that strokethe country. Through the application of a logit model to the responses collectedthrough a survey carried out on a sample of 200 individuals of the East regionof Cameroon, it was noticed that timber exploitation in a community frameworkdoes not necessarily lead to the strengthening of the links of belonging to acommon community, and to the equitable redistribution of revenues from theexploitation of the community forest.

  12. The Attitudes of Anglophone and Francophone Cameroonians towards Cameroon English as a Model of English Language Teaching and Learning in Cameroon

    Science.gov (United States)

    Atechi, Samuel; Angwah, Julius

    2016-01-01

    Teachers of English in Cameroon are proficient speakers of Cameroon English and their non-native status militates against their usage of Standard British English in the English language classrooms. This makes the attainment of British English thorny and perhaps impossible in Cameroon. Standing on that premise, we were motivated to find out…

  13. Volcanic gas

    Science.gov (United States)

    McGee, Kenneth A.; Gerlach, Terrance M.

    1995-01-01

    In Roman mythology, Vulcan, the god of fire, was said to have made tools and weapons for the other gods in his workshop at Olympus. Throughout history, volcanoes have frequently been identified with Vulcan and other mythological figures. Scientists now know that the “smoke" from volcanoes, once attributed by poets to be from Vulcan’s forge, is actually volcanic gas naturally released from both active and many inactive volcanoes. The molten rock, or magma, that lies beneath volcanoes and fuels eruptions, contains abundant gases that are released to the surface before, during, and after eruptions. These gases range from relatively benign low-temperature steam to thick hot clouds of choking sulfurous fume jetting from the earth. Water vapor is typically the most abundant volcanic gas, followed by carbon dioxide and sulfur dioxide. Other volcanic gases are hydrogen sulfide, hydrochloric acid, hydrogen, carbon monoxide, hydrofluoric acid, and other trace gases and volatile metals. The concentrations of these gas species can vary considerably from one volcano to the next.

  14. Clinical waste incinerators in Cameroon--a case study

    DEFF Research Database (Denmark)

    Mochungong, Peter Ikome Kuwoh; Gulis, Gabriel; Sodemann, Morten

    2012-01-01

    Incinerators are widely used to treat clinical waste in Cameroon's Northwest Region. These incinerators cause public apprehension owing to purported risks to operators, communities and the environment. This article aims to summarize findings from an April 2008 case study....

  15. Extended-spectrum-beta-lactamase-producing Enterobacteriaceae in Yaounde, Cameroon

    OpenAIRE

    Gangoue Pieboji, Joseph; Bedenic, B.; Koulla-Shiro, S.; Randegger, C.; Adiogo, D.; Ngassam, P.; Ndumbe, P; Hachler, H.

    2005-01-01

    Organisms producing extended-spectrum beta-lactamases (ESBLs) have been reported in many countries, but there is no information on the prevalence of ESBL-producing members of the family Enterobacteriaceae in Cameroon. A total of 259 Enterobacteriaceae strains were isolated between 1995 and 1998 from patients at the Yaounde Central Hospital in Cameroon. Enterobacterial isolates resistant to extended-spectrum cephalosporin and monobactam were screened for ESBL production by the double-disk (DD)...

  16. Extended-Spectrum-β-Lactamase-Producing Enterobacteriaceae in Yaounde, Cameroon

    OpenAIRE

    Gangoué-Piéboji, Joseph; Bedenic, Branka; Koulla-Shiro, Sinata; Randegger, Corinne; Adiogo, Dieudonné; Ngassam, Pierre; Ndumbe, Peter; Hächler, Herbert

    2005-01-01

    Organisms producing extended-spectrum β-lactamases (ESBLs) have been reported in many countries, but there is no information on the prevalence of ESBL-producing members of the family Enterobacteriaceae in Cameroon. A total of 259 Enterobacteriaceae strains were isolated between 1995 and 1998 from patients at the Yaounde Central Hospital in Cameroon. Enterobacterial isolates resistant to extended-spectrum cephalosporin and monobactam were screened for ESBL production by the double-disk (DD) sy...

  17. Volcanic Catastrophes

    Science.gov (United States)

    Eichelberger, J. C.

    2003-12-01

    The big news from 20th century geophysics may not be plate tectonics but rather the surprise return of catastrophism, following its apparent 19th century defeat to uniformitarianism. Divine miracles and plagues had yielded to the logic of integrating observations of everyday change over time. Yet the brilliant interpretation of the Cretaceous-Tertiary Boundary iridium anomaly introduced an empirically based catastrophism. Undoubtedly, decades of contemplating our own nuclear self-destruction played a role in this. Concepts of nuclear winter, volcanic winter, and meteor impact winter are closely allied. And once the veil of threat of all-out nuclear exchange began to lift, we could begin to imagine slower routes to destruction as "global change". As a way to end our world, fire is a good one. Three-dimensional magma chambers do not have as severe a magnitude limitation as essentially two-dimensional faults. Thus, while we have experienced earthquakes that are as big as they get, we have not experienced volcanic eruptions nearly as great as those preserved in the geologic record. The range extends to events almost three orders of magnitude greater than any eruptions of the 20th century. Such a calamity now would at the very least bring society to a temporary halt globally, and cause death and destruction on a continental scale. At maximum, there is the possibility of hindering photosynthesis and threatening life more generally. It has even been speculated that the relative genetic homogeneity of humankind derives from an evolutionary "bottleneck" from near-extinction in a volcanic cataclysm. This is somewhat more palatable to contemplate than a return to a form of Original Sin, in which we arrived at homogeneity by a sort of "ethnic cleansing". Lacking a written record of truly great eruptions, our sense of human impact must necessarily be aided by archeological and anthropological investigations. For example, there is much to be learned about the influence of

  18. [2 cases of sarcoidosis in Yaounde (Cameroon)].

    Science.gov (United States)

    Capdevielle, P; Vauterin, G; Mouden, J C; Darie, H

    1984-01-01

    Two new cases of sarcoidosis are reported from Cameroon. The first one concerned a man, 53 years old, who presented multiple dermal nodules of the face, polyadenopathy , splenomegaly, exertional dyspnea, reticular and micronodular aspect of lungs X-ray. Diagnosis was confirmed by histology of skin, ganglions and bronchus biopsies. Patient was treated by corticotherapy. The other one concerned a woman, 28 years old, who presented successively mediastinal adenopathies, then, 9 months later, reticular and micronodular aspect of lungs X-ray. During this period, a treatment against tuberculosis had been established. Bronchus biopsies confirmed the diagnosis. The patient was also treated by corticosteroids. The authors wonder whether sarcoidosis is actually or apparently rare in Negro-Africans, owing to the fact of frequent failure to recognize this affection, or confusion with tuberculosis. Correct incidence of sarcoidosis in Negro-Africans should be defined.

  19. Lead exposure from aluminum cookware in Cameroon

    Energy Technology Data Exchange (ETDEWEB)

    Weidenhamer, Jeffrey D.; Kobunski, Peter A. [Department of Chemistry, Geology and Physics, 401 College Ave., Ashland University, Ashland, OH 44805 (United States); Kuepouo, Gilbert [Research and Education Centre for Development (CREPD), Yaounde (Cameroon); Corbin, Rebecca W. [Department of Chemistry, Geology and Physics, 401 College Ave., Ashland University, Ashland, OH 44805 (United States); Gottesfeld, Perry, E-mail: pgottesfeld@okinternational.org [Occupational Knowledge International, San Francisco, CA (United States)

    2014-10-15

    Blood lead levels have decreased following the removal of lead from gasoline in most of the world. However, numerous recent studies provide evidence that elevated blood lead levels persist in many low and middle-income countries around the world at much higher prevalence than in the more developed countries. One potential source of lead exposure that has not been widely investigated is the leaching of lead from artisanal aluminum cookware, which is commonly used in the developing world. Twenty-nine samples of aluminum cookware and utensils manufactured by local artisans in Cameroon were collected and analyzed for their potential to release lead during cooking. Source materials for this cookware included scrap metal such as engine parts, radiators, cans, and construction materials. The lead content of this cookware is relatively low (< 1000 ppm by X-ray fluorescence), however significant amounts of lead, as well as aluminum and cadmium were released from many of the samples using dilute acetic acid extractions at boiling and ambient temperatures. Potential exposures to lead per serving were estimated to be as high as 260 μg, indicating that such cookware can pose a serious health hazard. We conclude that lead, aluminum and cadmium can migrate from this aluminum cookware during cooking and enter food at levels exceeding recommended public health guidelines. Our results support the need to regulate lead content of materials used to manufacture these pots. Artisanal aluminum cookware may be a major contributor to lead poisoning throughout the developing world. Testing of aluminum cookware in other developing countries is warranted. - Highlights: • Cookware is manufactured in Cameroon from scrap aluminum including car parts. • Twenty-nine cookware samples were evaluated for their potential to leach lead. • Boiling extractions to simulate the effects of cooking released significant lead. • Potential lead exposures per serving are estimated as high as 260 μg.

  20. Volcanic hazard management in dispersed volcanism areas

    Science.gov (United States)

    Marrero, Jose Manuel; Garcia, Alicia; Ortiz, Ramon

    2014-05-01

    Traditional volcanic hazard methodologies were developed mainly to deal with the big stratovolcanoes. In such type of volcanoes, the hazard map is an important tool for decision-makers not only during a volcanic crisis but also for territorial planning. According to the past and recent eruptions of a volcano, all possible volcanic hazards are modelled and included in the hazard map. Combining the hazard map with the Event Tree the impact area can be zoned and defining the likely eruptive scenarios that will be used during a real volcanic crisis. But in areas of disperse volcanism is very complex to apply the same volcanic hazard methodologies. The event tree do not take into account unknown vents, because the spatial concepts included in it are only related with the distance reached by volcanic hazards. The volcanic hazard simulation is also difficult because the vent scatter modifies the results. The volcanic susceptibility try to solve this problem, calculating the most likely areas to have an eruption, but the differences between low and large values obtained are often very small. In these conditions the traditional hazard map effectiveness could be questioned, making necessary a change in the concept of hazard map. Instead to delimit the potential impact areas, the hazard map should show the expected behaviour of the volcanic activity and how the differences in the landscape and internal geo-structures could condition such behaviour. This approach has been carried out in La Palma (Canary Islands), combining the concept of long-term hazard map with the short-term volcanic scenario to show the expected volcanic activity behaviour. The objective is the decision-makers understand how a volcanic crisis could be and what kind of mitigation measurement and strategy could be used.

  1. Energy, water and climate nexus: A case study of Cameroon

    DEFF Research Database (Denmark)

    Ackom, Emmanuel

    2014-01-01

    Cameroon is a country that is well endowed with natural resources including fertile arable lands, freshwater bodies, crude oil and other energy sources. The country's oil exploitation however results in significant pollution of Cameroon's land, water and air. Modern bioenergy is seen as having good...... potential to offset the reliance on crude oil. This study investigated the biomass resource availability from agricultural residues for liquid biofuel (as transportation fuel) and bioelectricity. Our findings indicate that sustainably extracted agricultural re sidues could yield 1.11 million bone dry tons......-38% of Cameroon's current electricity consumption. The potential water savings and avoided greenhouse gas missions from the use of agricultural residues for liquid biofuels and bioelectricity relative to crude oil have also been estimated. Modern bioenergy from agricultural residues does not pose concern to food...

  2. General overview of the disaster management framework in Cameroon.

    Science.gov (United States)

    Bang, Henry Ngenyam

    2014-07-01

    Efficient and effective disaster management will prevent many hazardous events from becoming disasters. This paper constitutes the most comprehensive document on the natural disaster management framework of Cameroon. It reviews critically disaster management in Cameroon, examining the various legislative, institutional, and administrative frameworks that help to facilitate the process. Furthermore, it illuminates the vital role that disaster managers at the national, regional, and local level play to ease the process. Using empirical data, the study analyses the efficiency and effectiveness of the actions of disaster managers. Its findings reveal inadequate disaster management policies, poor coordination between disaster management institutions at the national level, the lack of trained disaster managers, a skewed disaster management system, and a top-down hierarchical structure within Cameroon's disaster management framework. By scrutinising the disaster management framework of the country, policy recommendations based on the research findings are made on the institutional and administrative frameworks.

  3. Analytical Model of Underground Train Induced Vibrations on Nearby Building Structures in Cameroon: Assessment and Prediction

    Directory of Open Access Journals (Sweden)

    Lezin Seba MINSILI

    2013-11-01

    Full Text Available The purpose of this research paper was to assess and predict the effect of vibrations induced by an underground railway on nearby-existing buildings prior to the construction of projected new railway lines of the National Railway Master Plan of Cameroon and after upgrading of the railway conceded to CAMRAIL linking the two most densely populated cities of Cameroon: Douala and Yaoundé. With the source-transmitter-receiver mathematical model as the train-soil-structure interaction model, taking into account sub-model parameters such as type of the train-railway system, typical geotechnical conditions of the ground and the sensitivity of the nearby buildings, the analysis is carried out over the entire system using the dynamic finite element method in the time domain. This subdivision of the model is a powerful tool that allows to consider different alternatives of sub-models with different characteristics, and thus to determine any critical excessive vibration impact. Based on semi-empirical analytical results obtained from presented models, the present work assesses and predicts characteristics of traffic-induced vibrations as a function of time duration, intensity and vehicle speed, as well as their influence on buildings at different levels.

  4. Best practice guidelines for stroke in Cameroon: An innovative and participatory knowledge translation project

    Directory of Open Access Journals (Sweden)

    Lynn Cockburn

    2014-04-01

    Full Text Available Background: Although the adherence to stroke guidelines in high-income countries has been shown to be associated with improved patient outcomes, the research, development and implementation of rehabilitation related guidelines in African countries is lacking.Objectives: The purpose of this article is to describe how a group of front-line practitioners collaborated with academics and students to develop best practice guidelines (BPG for the management and rehabilitation of stroke in adult patients in Cameroon.Method: A working group was established and adapted internationally recognised processes for the development of best practice guidelines. The group determined the scope of the guidelines, documented current practices, and critically appraised evidence to develop guidelines relevant to the Cameroon context.Results: The primary result of this project is best practice guidelines which provided an overview of the provision of stroke rehabilitation services in the region, and made 83 practice recommendations to improve these services. We also report on the successes and challenges encountered during the process, and the working group’s recommendations aimed at encouraging others to consider similar projects.Conclusion: This project demonstrated that there is interest and capacity for improving stroke rehabilitation practices and for stroke guideline development in Africa.

  5. Extrathoracic heart in northern Cameroon: a case report

    Directory of Open Access Journals (Sweden)

    Alessandro Frigiola

    2009-06-01

    Full Text Available Tantchou et al report a case of ectopia cordis with successful surgical correction on a 7 months old child from northern Cameroon. Sternal clefts, ectopia cordis, and Cantrell's pentalogy continue to be very rare congenital anomalies in pediatric surgery. The prenatal diagnosis is easily made with ultrasound by visualizing the heart outside the thoracic cavity. Ectopia cordis is frequently associated with other congenital defects involving multiple organ systems. We report a case of ectopia cordis with successful surgical correction on a 7 months old child from northern Cameroon.

  6. Volcanic hazard assessment in monogenetic volcanic fields

    OpenAIRE

    Bartolini, Stefania

    2014-01-01

    [eng] One of the most important tasks of modern volcanology, which represents a significant socio-economic implication, is to conduct hazard assessment in active volcanic systems. These volcanological studies are aimed at hazard that allows to constructing hazard maps and simulating different eruptive scenarios, and are mainly addressed to contribute to territorial planning, definition of emergency plans or managing volcanic crisis. The impact of a natural event, as a volcanic eruption, can s...

  7. Linguistic Interference in a Multilingual Setting: The Case of Cameroon

    Science.gov (United States)

    Julius, Nashipu

    2006-01-01

    Cameroon, a central African state is one of the few countries in the world where, in addition to a very rich linguistically diverse landscape (a little below 300 identified indigenous languages) there is English and French (all vestiges of colonial legacy) used as official languages. Coupled with this, there is pidgin English which plays the role…

  8. REDD+ policy strategy in Cameroon: Actors, institutions and governance

    NARCIS (Netherlands)

    Somorin, O.A.; Visseren-Hamakers, I.J.; Arts, B.J.M.; Sonwa, D.J.; Tiani, A.

    2014-01-01

    Reducing emissions from deforestation and forest degradation (REDD+) is receiving increasing political and scientific attention as a climate change mitigation approach. The government of Cameroon has expressed an interest in participating in REDD+, and national deliberation on a policy strategy has

  9. Does malaria epidemiology project Cameroon as `Africa in miniature'?

    Indian Academy of Sciences (India)

    Huguette Gaelle Ngassa Mbenda; Gauri Awasthi; Poonam K Singh; Inocent Gouado; Aparup Das

    2014-09-01

    Cameroon, a west-central African country with a ∼20 million population, is commonly regarded as ‘Africa in miniature’ due to the extensive biological and cultural diversities of whole Africa being present in a single-country setting. This country is inhabited by ancestral human lineages in unique eco-climatic conditions and diverse topography. Over 90% Cameroonians are at risk of malaria infection, and ∼41% have at least one episode of malaria each year. Historically, the rate of malaria infection in Cameroon has fluctuated over the years; the number of cases was about 2 million in 2010 and 2011. The Cameroonian malaria control programme faces an uphill task due to high prevalence of multidrug-resistant parasites and insecticide-resistant malaria vectors. Above all, continued human migration from the rural to urban areas as well as population exchange with adjoining countries, high rate of ecological instabilities caused by deforestation, poor housing, lack of proper sanitation and drainage system might have resulted in the recent increase in incidences of malaria and other vector-borne diseases in Cameroon. The available data on eco-environmental variability and intricate malaria epidemiology in Cameroon reflect the situation in the whole of Africa, and warrant the need for in-depth study by using modern surveillance tools for meaningful basic understanding of the malaria triangle (host-parasite-vector-environment).

  10. Factors affecting livestock predation by lions in Cameroon

    NARCIS (Netherlands)

    Bommel, van L.; Vaate, bij de M.D.; Boer, de W.F.; Iongh, de H.H.

    2007-01-01

    Interviews were carried out in six villages south-west of Waza National Park, Cameroon, to investigate the impact of factors related to the occurrence of livestock raiding by lions. Data were analysed at the village and individual level. Livestock losses (cattle, sheep and/or goats) caused by lions

  11. The unfortunate sufferer: discursive dynamics around pregnancy loss in Cameroon

    NARCIS (Netherlands)

    E. van der Sijpt

    2013-01-01

    Pregnancy losses are ambiguous affairs in East Cameroon. Childbearing is not always people's primary aim within their fragile sexual and marital relationships, and it is often unclear to outsiders whether a pregnancy interruption is intended or unintended. Drawing on 15 months of fieldwork, I explor

  12. Catholic mission, colonial government and indigenous response in Kom (Cameroon)

    NARCIS (Netherlands)

    Vries, de J.

    1998-01-01

    This thesis illuminates the way in which a complex configuration of factors interacted in the first half of the 20th century to fundamentally transform the Kingdom of Kom in the Bamenda Grassfields of Cameroon. It examines the impact of colonial and missionary penetration, as well as the responses o

  13. Cameroon's main marketing board : history and scope of the ONCPB

    NARCIS (Netherlands)

    Laan, van der H.L.

    1987-01-01

    The creation of the ONCPB (Office national de commercialisation des produits de base) in 1976 was a turning point in the history of government regulation of agricultural marketing in Cameroon. It went a long way in unifying and harmonizing the marketing arrangements in francophone and anglophone Cam

  14. Treatment of malaria from monotherapy to artemisinin-based combination therapy by health professionals in urban health facilities in Yaoundé, central province, Cameroon

    OpenAIRE

    Bley Daniel; Malvy Denis; Vernazza-Licht Nicole; Gausseres Mathieu; Sayang Collins; Millet Pascal

    2009-01-01

    Abstract Background After adoption of artesunate-amodiaquine (AS/AQ) as first-line therapy for the treatment of uncomplicated malaria by the malaria control programme, this study was designed to assess the availability of anti-malarial drugs, treatment practices and acceptability of the new protocol by health professionals, in the urban health facilities and drugstores of Yaoundé city, Cameroon. Methods Between April and August 2005, retrospective and current information was collected by cons...

  15. Early warning indicators for HIV drug resistance in Cameroon during the year 2010.

    Directory of Open Access Journals (Sweden)

    Serge C Billong

    Full Text Available BACKGROUND: Rapid scale-up of antiretroviral therapy (ART in resource-limited settings is accompanied with an increasing risk of HIV drug resistance (HIVDR, which in turn could compromise the performance of national ART rollout programme. In order to sustain the effectiveness of ART in a resource-limited country like Cameroon, HIVDR early warning indicators (EWI may provide relevant corrective measures to support the control and therapeutic management of AIDS. METHODS: A retrospective study was conducted in 2010 among 40 ART sites (12 Approved Treatment Centers and 28 Management Units distributed over the 10 regions of Cameroon. Five standardized EWIs were selected for the evaluation using data from January through December, among which: (1 Good ARV prescribing practices: target = 100%; (2 Patient lost to follow-up: target ≤ 20%; (3 Patient retention on first line ART: target ≥ 70%; (4 On-time drug pick-up: target ≥ 90%; (5 ARV drug supply continuity: target = 100%. Analysis was performed using a Data Quality Assessment tool, following WHO protocol. RESULTS: THE NUMBER OF SITES ATTAINING THE REQUIRED PERFORMANCE ARE: 90% (36/40 for EWI(1, 20% (8/40 for EWI(2; 20% (8/40 for EWI(3; 0% (0/37 for EWI(4; and 45% (17/38 for EWI 5. ARV prescribing practices were in conformity with the national guidelines in almost all the sites, whereas patient adherence to ART (EWI(2, EWI(3, and EWI(4 was very low. A high rate of patients was lost-to-follow-up and others failing first line ART before 12 months of initiation. Discontinuity in drug supply observed in about half of the sites may negatively impact ARV prescription and patient adherence. These poor ART performances may also be due to low number of trained staff and community disengagement. CONCLUSIONS: The poor performance of the national ART programme, due to patient non-adherence and drug stock outs, requires corrective measures to limit risks of HIVDR emergence in Cameroon.

  16. Geoheritage at the Equator: Selected Geosites of São Tomé Island (Cameron Line, Central Africa

    Directory of Open Access Journals (Sweden)

    Maria Helena Henriques

    2015-01-01

    Full Text Available This work presents, for the first time, an overview of the rich geodiversity outcropping in the São Tomé island, one of the two islands that make up the archipelago of São Tomé and Príncipe, the second smallest state of Africa in area. Located at the equator, in the alignment known as the “Cameroon Volcanic Line”, this archipelago represents a privileged area for the comparative study between oceanic and continental alkaline volcanism, and therefore between the subcontinental and suboceanic mantle. Ten geosites of São Tomé island were selected, described and evaluated on the basis of their geoheritage value and using a qualitative system of classification, which integrates both the meaning attributed to the objects by scientific communities and the public understanding of such meanings related to its social use. The selected geosites display different heritage values (documental, scenic, symbolic, iconographic and indicial potentially usable for different purposes, namely scientific and educational, but mostly tourism. Geotourism can play a key role in the promotion of sustainable development in the Democratic Republic of São Tomé and Príncipe, and the geosites here described are likely to ground a geo-itinerary on this “pearl” of the Cameron Line.

  17. Challenges and conservation implications of the parrot trade in Cameroon

    OpenAIRE

    Simon A. Tamungang; Ofeh, Moses A.; Tchamba, Martin N.; Cheke, Robert A.; Kougoum, Ghislane P.

    2016-01-01

    Humans in every culture exploit wildlife resources around them to satisfy their immediate needs using many different methods. Similarly, parrots are exploited in Cameroon in various ways, for both consumptive and non-consumptive uses, by many cultures there. Trading in parrots is the biggest form of wild bird exploitation, and it is carried out by both the public and the private sectors, to satisfy both local and international demands. This paper therefore examined the challenges and conserva...

  18. Impact of agribusiness labour on the child education in Cameroon

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    Tiwang N Gildas

    2015-12-01

    Full Text Available This paper aimed to assess the involvement of child labour in agribusinesses as well as the schooling pattern of children involved in these agribusinesses in Cameroon. For this study, some descriptive statistics and cross tabulations were computed using SPSS.20 and stata 13 software packages. The population of this study was made up of 51,190 individuals of both sexes that were concerned by the third Cameroon National Household Survey. The sample drawn from this population was constituted of individuals of age 5-17 years old, making a total of 17,550 children. The main results of this study revealed that agribusiness child labour was present everywhere in Cameroon and by both boys and girls. Children of all ages of the sample were concerned by the phenomenon and their level of education was essentially the primary. The impact of agribusiness child labour on education was positive because it helped the working and schooling children to provide means to finance their education and other needs. On the other hand, it has a negative impact on education because some children went for these jobs and finally stayed there and did not return back to school.

  19. Particle Choices and Collocation in Cameroon English Phrasal Verbs

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    Napoleon Epoge

    2016-02-01

    Full Text Available The meaning of some phrasal verbs can be guessed from the meanings of the parts (to sit down = sit + down, run after = run + after and the meaning of some others have to be learned (to put up (a visitor = accommodate, to hold up = cause delay or try to rob someone due to their syntactic and semantic complexities. In this regard, the syntactic and semantic properties are expected to be the same in every English speaking context. Thus, this paper aims to explore the input-oriented syntactic and semantic properties of phrasal verbs in Cameroon English. Findings reveal that the syntactic property of some phrasal verbs undergoes innovative processes such as particle substitution (to round up a point, omission (to bite more than you can chew, and redundancy (to meet up with the requirements; while the semantic property undergoes the process of semantic extension (to came out with a pathetic story to justify ones absence from office; to come out with a wonderful strategy to curb corruption, and semantic shift (to put up with someone for one semester. This reveals that, in the New English context such as Cameroon, users resort to the domestication of the alien language as a functional and dominant paradigm to combat cultural imperialism and express new identity.Keywords: Cameroon English, collocation, particle, phrasal verb, semantics, syntax

  20. Dentofacial injuries in contact sports in Yaounde, Cameroon

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    M A Agbor

    2012-01-01

    Full Text Available Background: Dentofacial injuries constitute serious problems among competitive and recreational athletes, worldwide. Objective: To determine the prevalence of dentofacial injuries and related factors among individuals participating in contact sports in Yaoundé, Cameroon. Materials and Methods: This cross-sectional study among individuals participating in karate, judo, basketball, handball, football and wrestling in Yaoundé, Cameroon was conducted between January and April, 2012. Results: Of the 240 athletes interviewed, 115 and 89 of them reported bodily and dentofacial injuries giving 47.9% and 37.1% prevalence, respectively. The bodily injuries were limbs-(60.0%, chest-(23.5%, abdomen-(11.3% and neck- (5.2%. Mouth and face accounted for 52.8% and 37.1% of the dentofacial injuries, respectively. Other dentofacial injuries were teeth-(6.7% and mandible-(3.4%. Older athletes and years of participation were more likely to experience dentofacial injuries. Karate was the most common cause of dentofacial injuries followed by wrestling. The prevalence of the dentofacial injuries was similar among both genders and was equally prevalent during training and competition. The personal protective equipment use reduced the likelihood of dentofacial injuries among the athletes. Conclusion: The prevalence of dentofacial injuries were high while the personal protective equipment use was low among the individuals participating in contact sports in Yaoundé, Cameroon.

  1. Cryptoccocal meningitis in Yaoundé (Cameroon) HIV infected patients: Diagnosis, frequency and Cryptococcus neoformans isolates susceptibility study to fluconazole.

    Science.gov (United States)

    Kammalac Ngouana, T; Dongtsa, J; Kouanfack, C; Tonfack, C; Fomena, S; Mallié, M; Delaporte, E; Boyom, F-Fekam; Bertout, S

    2015-03-01

    Cryptococcal meningitis is a mycosis encountered especially in patients with Acquired Immunodeficiency Syndrome and is fatal in the absence of treatment. Information on epidemiology, diagnosis and susceptibility profile to antifungal drugs, are scarce in Cameroon. Authors evaluated the diagnosis possibilities of the cryptococcal meningitis in Cameroon, and studied the antifungal susceptibility of isolated strains to fluconazole, used as first line treatment of the disease in Cameroon. Between December 2009 and July 2011, 146 cerebrospinal fluids obtained from HIV patients with suspicion of meningitis were analysed. The diagnosis procedure involved macroscopic and cyto-chemical analysis, India ink test, culture on Sabouraud chloramphenicol medium and antigen latex agglutination test. Antifungal susceptibility testing of isolated strains to fluconazole was done by the E-test(®) method. The diagnosis of cryptococcal meningitis gave 28.08% positive cases. Among these patients, 80% were at stages III and IV and 20% at stage I of the HIV infection, according to the WHO previous classification. Cyto-chemical analysis showed current findings in the case of cryptococcal meningitis. India ink test and latex agglutination test exhibited very high sensitivity and specificity (>94%). Fluconazole antifungal susceptibility testing gave MICs lower than 32μg/mL to 92.7% of isolated strains and MICs greater than this value to 7.3% of isolates. These results showed that cryptococcal meningitis remains a real problem among HIV infected patients in Yaoundé. The emergence of fluconazole reduced susceptibility strains is worrying. Nevertheless, efficacy of rapid detection tests is interesting because this will help in rapid diagnosis and treatment of patients.

  2. Economic management in neo-colonial states : a case study of Cameroon

    NARCIS (Netherlands)

    Jua, N.

    1990-01-01

    This study examines the economic management strategies adopted by the Government of Cameroon. Economic planning in Cameroon has been anchored to the principles of planned liberalism, self-reliant development, balanced development and social justice. These concepts are elaborated and it is shown that

  3. Teachers' Perceptions of Students with Special Education Needs in Cameroon Secondary Schools

    Science.gov (United States)

    Arrah, Rosemary Oneke; Swain, Kristine D.

    2014-01-01

    This study examined teachers' perceptions of including students with special education needs in Cameroon secondary schools. Teachers (N = 130) from five secondary government, denominational or lay private schools in Buea subdivision of Cameroon, Africa, completed a 26-item survey. The survey was analyzed using descriptive statistics, t-tests, and…

  4. High prevalence and predominance of hepatitis delta virus genotype 1 infection in Cameroon.

    Science.gov (United States)

    Foupouapouognigni, Yacouba; Noah, Dominique Noah; Sartre, Michèle Tagni; Njouom, Richard

    2011-03-01

    Antibodies to the hepatitis delta virus (HDV) were found in 17.6% of 233 hepatitis B virus surface antigen-positive subjects in Cameroon. Phylogenetic analyses showed the presence of HDV-1, HDV-5, HDV-6, and HDV-7 genotypes. These results enrich the limited data on HDV prevalence and molecular diversity in Cameroon.

  5. Volcanic signals in oceans

    KAUST Repository

    Stenchikov, Georgiy L.

    2009-08-22

    Sulfate aerosols resulting from strong volcanic explosions last for 2–3 years in the lower stratosphere. Therefore it was traditionally believed that volcanic impacts produce mainly short-term, transient climate perturbations. However, the ocean integrates volcanic radiative cooling and responds over a wide range of time scales. The associated processes, especially ocean heat uptake, play a key role in ongoing climate change. However, they are not well constrained by observations, and attempts to simulate them in current climate models used for climate predictions yield a range of uncertainty. Volcanic impacts on the ocean provide an independent means of assessing these processes. This study focuses on quantification of the seasonal to multidecadal time scale response of the ocean to explosive volcanism. It employs the coupled climate model CM2.1, developed recently at the National Oceanic and Atmospheric Administration\\'s Geophysical Fluid Dynamics Laboratory, to simulate the response to the 1991 Pinatubo and the 1815 Tambora eruptions, which were the largest in the 20th and 19th centuries, respectively. The simulated climate perturbations compare well with available observations for the Pinatubo period. The stronger Tambora forcing produces responses with higher signal-to-noise ratio. Volcanic cooling tends to strengthen the Atlantic meridional overturning circulation. Sea ice extent appears to be sensitive to volcanic forcing, especially during the warm season. Because of the extremely long relaxation time of ocean subsurface temperature and sea level, the perturbations caused by the Tambora eruption could have lasted well into the 20th century.

  6. Volcanic evolution of the South Sandwich volcanic arc, South Atlantic, from multibeam bathymetry

    Science.gov (United States)

    Leat, Philip T.; Day, Simon J.; Tate, Alex J.; Martin, Tara J.; Owen, Matthew J.; Tappin, David R.

    2013-09-01

    New multibeam bathymetry data are presented for the South Sandwich intra-oceanic arc which occupies the small Sandwich plate in the South Atlantic, and is widely considered to be a simple end-member in the range of intra-oceanic arc types. The images show for the first time the distribution of submarine volcanic, tectonic and erosional-depositional features along the whole length of the 540 km long volcanic arc, allowing systematic investigation of along-arc variations. The data confirm that the volcanic arc has a simple structure composed of large volcanoes which form a well-defined volcanic front, but with three parallel cross-cutting seamount chains extending 38-60 km from near the volcanic front into the rear-arc. There is no evidence for intra-arc rifting or extinct volcanic lines. Topographic evidence for faulting is generally absent, except near the northern and southern plate boundaries. Most of the volcanic arc appears to be built on ocean crust formed at the associated back-arc spreading centre, as previously proposed from magnetic data, but the southern part of the arc appears to be underlain by older arc or continental crust whose west-facing rifted margin facing the back-arc basin is defined by the new bathymetry. The new survey shows nine main volcanic edifices along the volcanic front and ca. 20 main seamounts. The main volcanoes form largely glaciated islands with summits 3.0-3.5 km above base levels which are 2500-3000 m deep in the north and shallower at 2000-2500 m deep in the south. Some of the component seamounts are interpreted to have been active since the last glacial maximum, and so are approximately contemporaneous with the volcanic front volcanism. Seven calderas, all either submarine or ice-filled, have been identified: Adventure volcano, a newly discovered submarine volcanic front caldera volcano is described for the first time. All but one of the calderas are situated on summits of large volcanoes in the southern part of the arc, and

  7. Pteridophyta collected in Northern Nigeria and Northern Cameroon

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    Jan kornaś

    2014-01-01

    Full Text Available 25 species of Pteridophyta were collected in Northern Nigeria (mainly the Lake Chad Basin and the Mandara Mts. and in the neighbouring parts of Cameroon. 11 of them have not been recorded previously from this area: Isoetes schweinfurthii A. Br. in Bak., Selaginella tenerrima A. Br. ex Kuhn, Ophioglossum gomenzianum Welw. ex A. Br., Marsilea coromandeliana Willd., M. distorta A. Br., M. nubica A. Br., M. subterranea Lepr. ex A. Br., Azolla africana Desv., Ceratopteris richardii Brogn., Adiantum capillus-veneris Linn., and Actiniopleris semiflabellata Pic. Ser.

  8. Volcanic Rocks and Features

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Volcanoes have contributed significantly to the formation of the surface of our planet. Volcanism produced the crust we live on and most of the air we breathe. The...

  9. Gynaecological morbidity among HIV positive pregnant women in Cameroon

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    Nana Philip N

    2008-07-01

    Full Text Available Abstract Objective To compare the prevalence of gynaecological conditions among HIV infected and non-infected pregnant women. Methods Two thousand and eight (2008 pregnant women were screened for HIV, lower genital tract infections and lower genital tract neoplasia at booking antenatal visit. Results About 10% (198/2008 were HIV positive. All lower genital tract infections except candidiasis were more prevalent among HIV positive compared to HIV negative women: vaginal candidiasis (36.9% vs 35.4%; p = 0.678, Trichomoniasis (21.2% vs 10.6%; p p p = 0.026, syphilis (35.9% vs 10.6%; p Chlamydia trachomatis (38.4% vs 7.1%; p p p Conclusion We conclude that (i sexually transmitted infections (STIs are common in both HIV positive and HIV negative pregnant women in Cameroon, and (ii STIs and preinvasive cervical lesions are more prevalent in HIV-infected pregnant women compared to their non-infected compatriots. We recommend routine screening and treatment of STIs during antenatal care in Cameroon and other countries with similar social profiles.

  10. Poverty and Share Revenue in the Cameroon Cocoa Zone

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    Folefack, DP.

    2010-01-01

    Full Text Available This study evaluates the revenue level and unequal poverty revenue in the Cameroonian cocoa zone. The results show a great variability on the revenues generating activities to producers of cocoa in Cameroon. These activities generate an average revenue of 1 215 622 FCFA per year, with an annual average revenue of 145 933 FCFA per person. We realize through the indice of Gini 0.61 that the concentration of these revenues is most strong in Cameroon and the poverty rate is still affecting 69% of the population. We observe as well that the average revenue of 228 263 FCFA per year and per person for the producers of South West. They are thus the richest, inspite of the high degree of concentration. In the Centre, the population have a high average annual revenue of 87 257 FCFA per person and the concentration seems to be in a lower degree. Finally, in the South we find the poorest with a revenue of 53 504 FCFA per year and per person and the concentration is more important. An analysis based on unequal indicators shows in general that the revenue per person is relatively low and the degree of concentration of revenue is stronger in the Cameroonian cocoa zone.

  11. The Weight of Health Expenditures on Household Income in Cameroon

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    Joseph Parfait OWOUNDI

    2014-02-01

    Full Text Available  African leaders pledged at the Abuja conference in 2001, to mobilize more financial resources to allocate at least 15% of their national budgets to the health sector to achieve the Millennium Development Goals (MDGs, seem to have difficulty meeting this commitment because of weakness and fragmentation of health systems. These commitments were renewed in Gaborone, Botswana in 2005 and in Ouagadougou, Burkina Faso in 2006. Indeed, donor funding is still a large part of public health spending on the continent. In some countries, 50% or more of their budgets come from foreign or private assistance. In about half the countries, the private health financing is equal to or exceeds largely public funding, up to 70% in some states like Sudan, Côte d'Ivoire, Cameroon, Chad, Liberia and Uganda. Only five countries (Rwanda, Malawi, Zambia, Burkina Faso, and Togo have so far respected the promise made to the Abuja conference. In Cameroon, where 51% of the population lives on less than two dollars per day, the average propensity of the total medical consumption is very high. Indeed, 32% of households spend less than half of income on health, while 16% of households spend more than half of the income and 52% spend more than the total income. This corresponds to a weight of 68% in health care spending.  

  12. Local governance in disaster risk reduction in Cameroon

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    Buh-Wung Gaston

    2012-06-01

    Full Text Available At the 2005 World Conference on Disaster Risk Reduction held in Hyogo, Japan, 168 countries including Cameroon adopted the Hyogo Framework for Action, committing to take action to reduce human and socio-economic disaster losses. Geotechnology, Environmental Assessment and Disaster Risk Reduction was commissioned by the Global Network of Civil Society Organisations for Disaster Risk Reduction as the coordinating organisation in Cameroon to evaluate progress in implementation of the framework from the civil society perspective, particularly the role of local governance in disaster risk reduction (DRR. Seven regions of the country were identified for evaluation, where people have suffered losses from disasters during the last three decades. Three approaches were used: administration of questionnaires; consultations with local communities; and four case studies. It was found that there was significant scope for improvement on individual local governance indicators, and that effective progress depends on:1. level of achievement in the decentralisation process currently under way.2. adoption of a participatory approach to DRR.3. clear distribution of roles in the DRR process.4. adequate allocation of necessary financial and human resources.5. enhancement of capacity of local communities to prepare for and respond to all types of disasters.Creation of an independent body to carry out fundamental research, forecast new and emerging hazards and manage all disasters in the country will contribute greatly to moving things forward.

  13. Volcanic hazards to airports

    Science.gov (United States)

    Guffanti, M.; Mayberry, G.C.; Casadevall, T.J.; Wunderman, R.

    2009-01-01

    Volcanic activity has caused significant hazards to numerous airports worldwide, with local to far-ranging effects on travelers and commerce. Analysis of a new compilation of incidents of airports impacted by volcanic activity from 1944 through 2006 reveals that, at a minimum, 101 airports in 28 countries were affected on 171 occasions by eruptions at 46 volcanoes. Since 1980, five airports per year on average have been affected by volcanic activity, which indicates that volcanic hazards to airports are not rare on a worldwide basis. The main hazard to airports is ashfall, with accumulations of only a few millimeters sufficient to force temporary closures of some airports. A substantial portion of incidents has been caused by ash in airspace in the vicinity of airports, without accumulation of ash on the ground. On a few occasions, airports have been impacted by hazards other than ash (pyroclastic flow, lava flow, gas emission, and phreatic explosion). Several airports have been affected repeatedly by volcanic hazards. Four airports have been affected the most often and likely will continue to be among the most vulnerable owing to continued nearby volcanic activity: Fontanarossa International Airport in Catania, Italy; Ted Stevens Anchorage International Airport in Alaska, USA; Mariscal Sucre International Airport in Quito, Ecuador; and Tokua Airport in Kokopo, Papua New Guinea. The USA has the most airports affected by volcanic activity (17) on the most occasions (33) and hosts the second highest number of volcanoes that have caused the disruptions (5, after Indonesia with 7). One-fifth of the affected airports are within 30 km of the source volcanoes, approximately half are located within 150 km of the source volcanoes, and about three-quarters are within 300 km; nearly one-fifth are located more than 500 km away from the source volcanoes. The volcanoes that have caused the most impacts are Soufriere Hills on the island of Montserrat in the British West Indies

  14. Addressing urban sprawl in Douala, Cameroon: Lessons from Xiamen integrated coastal management

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    Suinyuy Derrick Ngoran

    2015-06-01

    The conclusions of this effort portray that sprawl in Cameroon is caused by inadequate policy implementation, outdated master plan, insufficient information, disparity in resources distribution among the different regions of the State and the gaps expounded by the traditional management. Grounded in the knowledge drawn from Xiamen ICM, the paper recommends the creation of an autonomous coastal interagency in Douala to address the gaps disrupted by sectoral management, and thus, improve coastal management in Cameroon.

  15. Retention in an antiretroviral therapy programme during an era of decreasing drug cost in Limbe, Cameroon

    OpenAIRE

    Mosoko Jembia J; Akam Wilfred; Weidle Paul J; Brooks John T; Aweh Asabi J; Kinge Thompson N; Pals Sherri; Raghunathan Pratima L

    2011-01-01

    Abstract Background In 2002, Cameroon initiated scale up of antiretroviral therapy (ART); on 1 October 2004, a substantial reduction in ART cost occurred. We assessed the impact of this event and other factors on enrolment and retention in care among HIV-infected patients initiating ART from February 2002 to December 2005 at the single ART clinic serving the Southwest Region in Limbe, Cameroon. Methods We retrospectively analyzed clinical and pharmacy payment records of HIV-infected patients ...

  16. Precambrian Lunar Volcanic Protolife

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    Jack Green

    2009-06-01

    Full Text Available Five representative terrestrial analogs of lunar craters are detailed relevant to Precambrian fumarolic activity. Fumarolic fluids contain the ingredients for protolife. Energy sources to derive formaldehyde, amino acids and related compounds could be by flow charging, charge separation and volcanic shock. With no photodecomposition in shadow, most fumarolic fluids at 40 K would persist over geologically long time periods. Relatively abundant tungsten would permit creation of critical enzymes, Fischer-Tropsch reactions could form polycyclic aromatic hydrocarbons and soluble volcanic polyphosphates would enable assembly of nucleic acids. Fumarolic stimuli factors are described. Orbital and lander sensors specific to protolife exploration including combined Raman/laser-induced breakdown spectrocsopy are evaluated.

  17. Volcanism and Oil & Gas In Northeast China

    Institute of Scientific and Technical Information of China (English)

    Shan Xuanlong

    2000-01-01

    Based on study on the relation with volcanic rock and oil & gas in Songliao Basin and Liaohe Basin in northeast China, author proposes that material from deep by volcanism enrichs the resources in basins, that heat by volcanism promotes organic matter transforming to oil and gas, that volcanic reservoir is fracture, vesicular, solution pore, intercrystal pore.Lava facies and pyroclastic facies are favourable reservoir. Mesozoic volcanic reservoir is majority of intermediate, acid rock,but Cenozoic volcanic reservoir is majority of basalt. Types of oil and gas pool relating to volcanic rock include volcanic fracture pool, volcanic unconformity pool, volcanic rock - screened pool, volcanic darpe structural pool.

  18. Alcohol use and extramarital sex among men in Cameroon

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    Wiysonge Charles

    2007-08-01

    Full Text Available Abstract Background The spread of HIV in sub-Saharan Africa is believed to be driven by unsafe sex, and identification of modifiable risk factors of the latter is needed for comprehensive HIV prevention programming in the region. Some previous studies suggest an association between alcohol abuse and unsafe sexual behaviour, such as multiple concurrent sexual partnerships and inconsistent condom use in sex with non-spousal non-cohabiting partners. However, most of these studies were conducted in developed countries and the few studies in Africa were conducted among well-defined social groups such as men attending beer halls or sexually transmitted infection clinics. We therefore examined the association between alcohol and extramarital sex (a sign of multiple concurrent sexual partnerships among men in a population-based survey in Cameroon; a low-income country in sub-Saharan Africa with a high rate of alcohol abuse and a generalised HIV epidemic. Methods We analyzed data from 2678 formally married or cohabiting men aged 15 to 59 years, who participated in the 2004 Cameroon Demographic and Health Survey, using a multivariate regression model. Results A quarter of the men (25.8% declared having taken alcohol before their last sexual intercourse and 21% indicated that the last sex was with a woman other than their wife or cohabiting partner. After controlling for possible confounding by other socio-demographic characteristics, alcohol use was significantly associated with having extramarital sex: adjusted odds ratio (OR 1.70, 95% confidence intervals (CI 1.40 to 2.05. Older age (30–44 years: OR 3.06, 95%CI 2.16–4.27 and 45–59 years: OR 4.10, 95%CI 2.16–4.27, higher education (OR 1.25, 95%CI 1.10–1.45, and wealth (OR 1.71, 95%CI 1.50–1.98 were also significantly associated with higher odds of having extramarital sex. The men were more likely to have used a condom in their last sex if it was extramarital (OR 10.50, 95%CI 8.10–13

  19. Wealth and sexual behaviour among men in Cameroon

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    Nana Philip

    2006-09-01

    Full Text Available Abstract Background The 2004 Demographic and Health Survey (DHS in Cameroon revealed a higher prevalence of HIV in richest and most educated people than their poorest and least educated compatriots. It is not certain whether the higher prevalence results partly or wholly from wealthier people adopting more unsafe sexual behaviours, surviving longer due to greater access to treatment and care, or being exposed to unsafe injections or other HIV risk factors. As unsafe sex is currently believed to be the main driver of the HIV epidemic in sub-Saharan Africa, we designed this study to examine the association between wealth and sexual behaviour in Cameroon. Methods We analysed data from 4409 sexually active men aged 15–59 years who participated in the Cameroon DHS using logistic regression models, and have reported odds ratios (OR with confidence intervals (CI. Results When we controlled for the potential confounding effects of marital status, place of residence, religion and age, men in the richest third of the population were less likely to have used a condom in the last sex with a non-spousal non-cohabiting partner (OR 0.43, 95% CI 0.32–0.56 and more likely to have had at least two concurrent sex partners in the last 12 months (OR 1.38, 95% CI 1.12–1.19 and more than five lifetime sex partners (OR 1.97, 95% CI 1.60–2.43. However, there was no difference between the richest and poorest men in the purchase of sexual services. Regarding education, men with secondary or higher education were less likely to have used a condom in the last sex with a non-spousal non-cohabiting partner (OR 0.24, 95% CI 0.16–0.38 and more likely to have started sexual activity at age 17 years or less (OR 2.73, 95% CI 2.10–3.56 and had more than five lifetime sexual partners (OR 2.59, 95% CI 2.02–3.31. There was no significant association between education and multiple concurrent sexual partnerships in the last 12 months or purchase of sexual services

  20. Electricity Self-Generation Costs for Industrial Companies in Cameroon

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    Diboma Benjamin Salomon

    2010-07-01

    Full Text Available Industrial production in developing countries (DC is frequently perturbed by electric energy supply difficulties. To overcome this problem, generators are used in self-generation of energy, but this leads to an increase of electricity-related expenses. This article assesses the impact of electricity self-generation on Cameroonian industrial companies. The model described in this article is based on data collected through a survey of a representative sample of industrial companies and from numerous previous thematic and statistical studies. The results of our analyses show that expenses related to electricity in industrial companies in Cameroon have increased five times due to electricity rationing and untimely power cuts. The article also suggests some solutions to improve the electricity self-generation capacity of industrial companies.

  1. Timing of Premarital Intercourse in Bandjoun (West Cameroon

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    Zacharie Tsala Dimbuene

    2013-03-01

    Full Text Available This article examined the effects of family environment on the risks of premarital intercourse for male and female youth. Previous research in sub-Saharan Africa (SSA on the linkages between family structures and sexual debut mainly utilized cross-sectional data. In a sample drawn from Cameroon Family and Health Survey (N = 2,166, descriptive and multivariate results showed that youth who resided in nuclear two-parent families, those who reported higher levels of parental monitoring and higher quality of parent–child relationships during childhood and/or adolescence, had significantly lower rates of premarital intercourse. Polygynous families, parent–child communication, orphanhood, and change in family structure were significantly associated with higher rates of premarital intercourse. Programmatic implications for reproductive health interventions in SSA are discussed.

  2. Mechanisms for Quality Assurance of Universities in Cameroon

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    Joseph BESONG BESONG

    2016-06-01

    Full Text Available This paper takes a perspective look at the evolution of universities in Cameroon and the recent orientation of deregulation as it affects quality assurance in Cameroonian universities. The paper having identified these flaws attempted to elucidate the meaning of mechanism for Quality assurance in the face of deregulation. The regulatory mechanisms identified by this paper include inter- alia, appropriate scrutiny of new programmes, relying on impartial advise of examiners. Using the state law NO.98/004 of 1998 to compliment the efforts of internal school administration and above all opening linkages between universities and relating universities education in the World of science and technology. This paper does not only enhance quality assurance but also builds the idea of economic growth and development.

  3. Tracing the origins of rescued chimpanzees reveals widespread chimpanzee hunting in Cameroon

    Directory of Open Access Journals (Sweden)

    Gadsby Elizabeth L

    2010-01-01

    Full Text Available Abstract Background While wild chimpanzees are experiencing drastic population declines, their numbers at African rescue and rehabilitation projects are growing rapidly. Chimpanzees follow complex routes to these refuges; and their geographic origins are often unclear. Identifying areas where hunting occurs can help law enforcement authorities focus scarce resources for wildlife protection planning. Efficiently focusing these resources is particularly important in Cameroon because this country is a key transportation waypoint for international wildlife crime syndicates. Furthermore, Cameroon is home to two chimpanzee subspecies, which makes ascertaining the origins of these chimpanzees important for reintroduction planning and for scientific investigations involving these chimpanzees. Results We estimated geographic origins of 46 chimpanzees from the Limbe Wildlife Centre (LWC in Cameroon. Using Bayesian approximation methods, we determined their origins using mtDNA sequences and microsatellite (STRP genotypes compared to a spatial map of georeferenced chimpanzee samples from 10 locations spanning Cameroon and Nigeria. The LWC chimpanzees come from multiple regions of Cameroon or forested areas straddling the Cameroon-Nigeria border. The LWC chimpanzees were partitioned further as originating from one of three biogeographically important zones occurring in Cameroon, but we were unable to refine these origin estimates to more specific areas within these three zones. Conclusions Our findings suggest that chimpanzee hunting is widespread across Cameroon. Live animal smuggling appears to occur locally within Cameroon, despite the existence of local wildlife cartels that operate internationally. This pattern varies from the illegal wildlife trade patterns observed in other commercially valuable species, such as elephants, where specific populations are targeted for exploitation. A broader sample of rescued chimpanzees compared against a more

  4. Modeling volcanic ash dispersal

    CERN Document Server

    CERN. Geneva

    2010-01-01

    The assessment of volcanic fallout hazard is an important scientific, economic, and political issue, especially in densely populated areas. From a scientific point of view, considerable progress has been made during the last two decades through the use of increasingly powerful computational models and capabilities. Nowadays, models are used to quantify hazard...

  5. Maternal mortality in Cameroon: a university teaching hospital report.

    Science.gov (United States)

    Tebeu, Pierre-Marie; Pierre-Marie, Tebeu; Halle-Ekane, Gregory; Gregory, Halle-Ekane; Da Itambi, Maxwell; Maxwell, Da Itambi; Enow Mbu, Robinson; Robinson, Enow Mbu; Mawamba, Yvette; Yvette, Mawamba; Fomulu, Joseph Nelson; Nelson, Fomulu Joseph

    2015-01-01

    More than 550,000 women die yearly from pregnancy-related causes. Fifty percent (50%) of the world estimate of maternal deaths occur in sub-Saharan Africa alone. There is insufficient information on the risk factors of maternal mortality in Cameroon. This study aimed at establishing causes and risk factors of maternal mortality. This was a case-control study from 1st January, 2006 to 31st December, 2010 after National Ethical Committee Approval. Cases were maternal deaths; controls were women who delivered normally. Maternal deaths were obtained from the delivery room registers and in-patient registers. Controls for each case were two normal deliveries following identified maternal deaths on the same day. Variables considered were socio-demographic and reproductive health characteristics. Epi Info 3.5.1 was used for analysis. The mean MMR was 287.5/100,000 live births. Causes of deaths were: postpartum hemorrhage (229.2%), unsafe abortion (25%), ectopic pregnancy (12.5%), hypertension in pregnancy (8.3%), malaria (8.3%), anemia (8.3%), heart disease (4.2%), and pneumonia (4.2%), and placenta praevia (4.2%). Ages ranged from 18 to 41 years, with a mean of 27.7 ± 5.14 years. Lack of antenatal care was a risk factor for maternal death (OR=78.33; CI: (8.66- 1802.51)). The mean MMR from 2006 to 2010 was 287.5/100,000 live births. Most of the causes of maternal deaths were preventable. Lack of antenatal care was a risk factor for maternal mortality. Key words: Maternal mortality, causes, risk factors, Cameroon.

  6. Crustal radial anisotropy beneath Cameroon from ambient noise tomography

    Science.gov (United States)

    Ojo, Adebayo Oluwaseun; Ni, Sidao; Li, Zhiwei

    2017-01-01

    To increase the understanding of crustal deformation and crustal flow patterns due to tectonic processes in Cameroon, we study the lateral variability of the crustal isotropic velocity and radial anisotropy estimated using Ambient Noise Tomography (ANT). Rayleigh and Love wave Noise Correlation Functions (NCFs) were retrieved from the cross-correlation of seismic ambient noise data recorded in Cameroon, and phase velocities at periods of 8 to 30 s were measured to perform surface wave tomography. Joint inversion of Rayleigh and Love wave data for isotropic velocity models could not fit the observed dispersions simultaneously. We attribute the Love-Rayleigh discrepancy to the presence of radial anisotropy in the crust and estimated its magnitude. Our 3-D radial anisotropic model reveals the spatial variation of strong to weak positive (Vsh > Vsv) and negative (Vsv > Vsh) radial anisotropy in the crust. We observe negative radial anisotropy in the upper crust that is associated mainly with the location of a previously reported mantle plume. The anisotropy could be attributed to the vertical alignment of fossil microcracks or metamorphic foliations due to the upwelling of plume material. A strong positive radial anisotropy is centered at the location of an inferred boundary between the Congo Craton and the Oubanguides Belt that might be related to the preferred orientation of crustal anisotropic minerals associated with shearing in this fault zone. The middle crust is characterized by a widespread negative radial anisotropy that is likely caused by the flow-induced alignment of anisotropic minerals that crystallized during magma intrusion. The magnitude of the radial anisotropy varies systematically from predominantly negative in the middle crust to positive in the lower crust. The imaged patterns of the isotropic velocity and radial anisotropy are consistent with previous studies and agree with regional tectonics.

  7. Aurorae and Volcanic Eruptions

    Science.gov (United States)

    2001-06-01

    Thermal-IR Observations of Jupiter and Io with ISAAC at the VLT Summary Impressive thermal-infrared images have been obtained of the giant planet Jupiter during tests of a new detector in the ISAAC instrument on the ESO Very Large Telescope (VLT) at the Paranal Observatory (Chile). . They show in particular the full extent of the northern auroral ring and part of the southern aurora. A volcanic eruption was also imaged on Io , the very active inner Jovian moon. Although these observations are of an experimental nature, they demonstrate a great potential for regular monitoring of the Jovian magnetosphere by ground-based telescopes together with space-based facilities. They also provide the added benefit of direct comparison with the terrestrial magnetosphere. PR Photo 21a/01 : ISAAC image of Jupiter (L-band: 3.5-4.0 µm) . PR Photo 21b/01 : ISAAC image of Jupiter (Narrow-band 4.07 µm) . PR Photo 21c/01 : ISAAC image of Jupiter (Narrow-band 3.28 µm) . PR Photo 21d/01 : ISAAC image of Jupiter (Narrow-band 3.21 µm) . PR Photo 21e/01 : ISAAC image of the Jovian aurorae (false-colour). PR Photo 21f/01 : ISAAC image of volcanic activity on Io . Addendum : The Jovian aurorae and polar haze. Aladdin Meets Jupiter Thermal-infrared images of Jupiter and its volcanic moon Io have been obtained during a series of system tests with the new Aladdin detector in the Infrared Spectrometer And Array Camera (ISAAC) , in combination with an upgrade of the ESO-developed detector control electronics IRACE. This state-of-the-art instrument is attached to the 8.2-m VLT ANTU telescope at the ESO Paranal Observatory. The observations were made on November 14, 2000, through various filters that isolate selected wavebands in the thermal-infrared spectral region [1]. They include a broad-band L-filter (wavelength interval 3.5 - 4.0 µm) as well as several narrow-band filters (3.21, 3.28 and 4.07 µm). The filters allow to record the light from different components of the Jovian atmosphere

  8. Batrachochytrium dendrobatidis in amphibians of Cameroon, including first records for caecilians.

    Science.gov (United States)

    Doherty-Bone, T M; Gonwouo, N L; Hirschfeld, M; Ohst, T; Weldon, C; Perkins, M; Kouete, M T; Browne, R K; Loader, S P; Gower, D J; Wilkinson, M W; Rödel, M O; Penner, J; Barej, M F; Schmitz, A; Plötner, J; Cunningham, A A

    2013-02-28

    Amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd) has been hypothesised to be an indigenous parasite of African amphibians. In Cameroon, however, previous surveys in one region (in the northwest) failed to detect this pathogen, despite the earliest African Bd having been recorded from a frog in eastern Cameroon, plus one recent record in the far southeast. To reconcile these contrasting results, we present survey data from 12 localities across 6 regions of Cameroon from anurans (n = 1052) and caecilians (n = 85) of ca. 108 species. Bd was detected in 124 amphibian hosts at 7 localities, including Mt. Oku, Mt. Cameroon, Mt. Manengouba and lowland localities in the centre and west of the country. None of the hosts were observed dead or dying. Infected amphibian hosts were not detected in other localities in the south and eastern rainforest belt. Infection occurred in both anurans and caecilians, making this the first reported case of infection in the latter order (Gymnophiona) of amphibians. There was no significant difference between prevalence and infection intensity in frogs and caecilians. We highlight the importance of taking into account the inhibition of diagnostic qPCR in studies on Bd, based on all Bd-positive hosts being undetected when screened without bovine serum albumin in the qPCR mix. The status of Bd as an indigenous, cosmopolitan amphibian parasite in Africa, including Cameroon, is supported by this work. Isolating and sequencing strains of Bd from Cameroon should now be a priority. Longitudinal host population monitoring will be required to determine the effects, if any, of the infection on amphibians in Cameroon.

  9. Exploring Hawaiian volcanism

    Science.gov (United States)

    Poland, Michael P.; Okubo, Paul G.; Hon, Ken

    2013-01-01

    In 1912 the Hawaiian Volcano Observatory (HVO) was established by Massachusetts Institute of Technology professor Thomas A. Jaggar Jr. on the island of Hawaii. Driven by the devastation he observed while investigating the volcanic disasters of 1902 at Montagne Pelée in the Caribbean, Jaggar conducted a worldwide search and decided that Hawai‘i provided an excellent natural laboratory for systematic study of earthquake and volcano processes toward better understanding of seismic and volcanic hazards. In the 100 years since HVO’s founding, surveillance and investigation of Hawaiian volcanoes have spurred advances in volcano and seismic monitoring techniques, extended scientists’ understanding of eruptive activity and processes, and contributed to development of global theories about hot spots and mantle plumes.

  10. Exploring Hawaiian Volcanism

    Science.gov (United States)

    Poland, Michael P.; Okubo, Paul G.; Hon, Ken

    2013-02-01

    In 1912 the Hawaiian Volcano Observatory (HVO) was established by Massachusetts Institute of Technology professor Thomas A. Jaggar Jr. on the island of Hawaii. Driven by the devastation he observed while investigating the volcanic disasters of 1902 at Montagne Pelée in the Caribbean, Jaggar conducted a worldwide search and decided that Hawai`i provided an excellent natural laboratory for systematic study of earthquake and volcano processes toward better understanding of seismic and volcanic hazards. In the 100 years since HVO's founding, surveillance and investigation of Hawaiian volcanoes have spurred advances in volcano and seismic monitoring techniques, extended scientists' understanding of eruptive activity and processes, and contributed to development of global theories about hot spots and mantle plumes.

  11. Are there biomedical criteria to assess an acute carbon dioxide intoxication by a volcanic emission?

    Science.gov (United States)

    Stupfel, Maurice; Le Guern, François

    1989-11-01

    On August 21, 1987, more than 1800 people, thousands of head of cattle and countless wild animals, including birds, were killed by a gas release which occurred during about 4 hours at the lake in the crater Iwi at Nyos in Cameroon; plant life was mostly unaffected. An international inquiry was performed by British, French, Italian, Japanese and U.S. volcanologists and physicians to determine what had been the cause of this disaster. An international conference organised by United Nations Educational Scientific, and Cultural Organisation (U.N.E.S.C.O.), the Cameroon Government and the U.N. Economic Commission for Africa held in Yaoundé March, 1987 concluded: 'that the cause of sudden death was suffocation (asphyxia) in a carbon dioxide atmosphere' The medical findings have been explained by asphyxia caused by carbon dioxide. The presence of other volcanic gases, e.g. hydrogen sulfide, cannot be ruled out' (Sigvaldason, 1989, this issue). This paper reviews what is mainly known about an acute carbon dioxide intoxication in order to disprove or confirm the diagnosis and helps to interpret the field observations and testimonies to provide a basis to discuss the prevention of such an intoxication.

  12. Geomagnetic imprint of the Persani volcanism

    Science.gov (United States)

    Besutiu, Lucian; Seghedi, Ioan; Zlagnean, Luminita; Atanasiu, Ligia; Popa, Razvan-Gabriel; Pomeran, Mihai; Visan, Madalina

    2016-04-01

    employing various filtering techniques. Thus, the reduction-to-the-pole or pseudo-gravity operators have allowed for an improved source positioning, distorted by the inclination of the geomagnetic vector, while high-order derivatives (e.g. horizontal and vertical gradients) have better outlined the contour of the hidden magnetic bodies. Overall, the geomagnetic survey has confirmed the assumptions previously inferred by geological field work. Besides, it helped identify several unrevealed buried volcanic forms and their relation to structural elements (e.g. fault aligned vents, and larger circular structures). In-depth development of the volcanic structures has been studied along several interpretative lines by using inversion and 2D forward modelling of geomagnetic data under rock magnetic properties constraints provided by lab analyses. Acknowledgements. The research was funded through CNCS - UEFISCDI, project number PN-II-ID-PCE-2012-4-0137.

  13. Community pico and micro hydropower for rural electrification: experiences from the mountain regions of Cameroon

    Directory of Open Access Journals (Sweden)

    Stefano Mandelli

    2016-02-01

    Full Text Available Less than 15% of rural areas of Cameroon have access to grid electricity. Only 53% of the population has access to grid electricity. Notwithstanding, Cameroon has a huge hydropower potential which could be harnessed. Mini grids, powered by pico and micro hydropower plants, are a relatively new rural electrification strategy in Cameroon. Several of such mini grids have been realized in the mountain regions of the country. Some of these systems have been more successful than others. This paper aims to share the experiences of community-based pico and micro hydropower schemes for rural electrification in Cameroon. The paper provides insight to the challenges that three of such mini grid systems powered by pico and micro hydropower plants had encountered and it attempts to identify issues related to their performances. The study was based on personal experience, field visits, participant observations, interviews and focus group discussions with key members of the beneficiary communities and documentations from the local NGO which implemented the schemes. Key findings of this study relate to the description of the main aspects about: planning of a robust system design, organizational aspects, like social cohesion at all levels of scheme management, community leadership and ownership of the system and involvement of the beneficiaries at all stages of the project cycle. These aspects were particularly addressed within the context of rural communities in Cameroon.

  14. Sustainable Development and Corporate Social Responsibility in Sub-Saharan Africa: Evidence from Industries in Cameroon

    Directory of Open Access Journals (Sweden)

    Oyewole Simon Oginni

    2016-05-01

    Full Text Available Present technological innovations and social organizations continue to impose risks and limitations on the efficient performance of the biosphere. Human activities have increasingly short-lived sustainable natural endowments, to the extent that, the multiplier effects have ripples beyond the traditional benefits of economic production and consumption. Therefore, this study addressed practical concerns on how industries in Sub-Saharan Africa promote sustainable development in their corporate social responsibility models, using industries in Cameroon as a case study; it examined economic, social, and environmental components of sustainable development and corporate social responsibility (CSR. Our sample consists of 335 business enterprises from the last Censure Survey of Enterprises in Cameroon. The study adopted a systematic analysis through the Adjusted Residual Test, and the Phi and Cramer’s V tests. Findings revealed that industries in Cameroon prioritize environmental and social dimensions over economic dimensions. However, a few large enterprises implement a broad CSR that promotes sustainable business practices, whereas smaller ones do not; industries in Cameroon implement environmental dimensions of CSR as a safe buffer and a social dimension as philanthropy. Hence, there is no concrete evidence that industries promote sustainable development via CSR in Cameroon. The implementation of a sustainable business model is a precondition for promoting sustainable development via CSR. Industries should realize the concrete value in implementing a sustainable business model that helps to adjust to the complex and increasingly changing business environment.

  15. Subdiffusion of volcanic earthquakes

    CERN Document Server

    Abe, Sumiyoshi

    2016-01-01

    A comparative study is performed on volcanic seismicities at Mt.Eyjafjallajokull in Iceland and Mt. Etna in Sicily, Italy, from the viewpoint of science of complex systems, and the discovery of remarkable similarities between them regarding their exotic spatio-temporal properties is reported. In both of the volcanic seismicities as point processes, the jump probability distributions of earthquakes are found to obey the exponential law, whereas the waiting-time distributions follow the power law. In particular, a careful analysis is made about the finite size effects on the waiting-time distributions, and accordingly, the previously reported results for Mt. Etna [S. Abe and N. Suzuki, EPL 110, 59001 (2015)] are reinterpreted. It is shown that spreads of the volcanic earthquakes are subdiffusive at both of the volcanoes. The aging phenomenon is observed in the "event-time-averaged" mean-squared displacements of the hypocenters. A comment is also made on presence/absence of long term memories in the context of t...

  16. Current cancer incidence and trends in Yaounde, Cameroon

    Directory of Open Access Journals (Sweden)

    Enow Orock GE

    2014-05-01

    Full Text Available Background: Except for some information on relative frequencies of different cancers in selected areas, the epidemiology of cancer in Cameroon is relatively unknown. Though there is no reliable data on its incidence and pattern, with an estimated 15,000 new cases diagnosed annually and a prevalence of about 25.000 cases throughout the country, cancer is being increasingly recognized as a public health problem in Cameroon. The Yaounde Cancer Registry is a population registry physically located at the General Hospital Yaounde that has been operating since 2004. It collects data from about 20 sources that cover the entire population of Yaounde estimated in 2010 at about 1,299,369. Objectives: The objective of this study was to find out the incidence and trends of cancer in the Yaounde population in the period 2004 – 2006/2010 – 2011. It is hoped that this will enable policy makers, health providers and other stake holders plan appropriate health management policy in this population. Materials and Methods: This report presents the cancer incidence for 5 years, 2004 – 2006/2010 – 2011 in the Yaounde population estimated at 1,299,369. Data of the Yaounde Cancer Registry was reviewed for the period under study using Canreg5 software. Only malignant cases registered during the period under study were used in the analysis while benign and other uncertain tumours were excluded. The 2010 census estimates by the National Institute of Statistics was employed to calculate the incidence, age-standardized and crude rates. Other software like excel, epi info were also used for analysis. Survival studies were not carried out in this study. Results: A total of 4,689 new malignant cases were reported, of which 2,901 (68% were females and 1,788 (32% were males. The incidence showed an average of 358 for men and 580 for women. The average age of cancer patients in Yaounde is 44.8 years. Morphologically confirmed cases accounted for 89% .The annual number of

  17. ETINDE. Improving the role of a methodological approach and ancillary ethnoarchaeological data application for place vulnerability and resilience to a multi-hazard environment: Mt. Cameroon volcano case study [MIA-VITA project -FP7-ENV-2007-1

    Science.gov (United States)

    Ilaria Pannaccione Apa, Maria; Kouokam, Emmanuel; Mbe Akoko, Robert; Peppoloni, Silvia; Fabrizia Buongiorno, Maria; Thierry, Pierre

    2013-04-01

    The FP7 MIA-VITA [Mitigate and assess risk from volcanic impact on terrain and human activities] project has been designed to address multidisciplinary aspects of volcanic threat assessment and management from prevention to crisis management recovery. In the socio-economic analysis carried out at Mt. Cameroon Bakweri and Bakossi ethnic groups, ancillary ethnoarchaeological information has been included to point out the cultural interaction between the volcano and its residents. In 2009-2011, ethnoanthropological surveys and interviews for data collection were carried out at Buea, Limbe, West Coast, Tiko and Muyuka sub-divisions adjacent to Mt. Cameroon. One of the outstanding, results from the Bakweri and Bakossi cultural tradition study: natural hazards are managed and produced by supernatural forces, as: Epasa Moto, God of the Mountain (Mt. Cameroon volcano) and Nyango Na Nwana , Goddess of the sea (Gulf of Guinea). In the case of Mount Cameroon, people may seek the spirit or gods of the mountain before farming, hunting and most recently the undertaking of the Mount Cameroon annual race are done. The spirit of this mountain must be seek to avert or stop a volcanic eruption because the eruption is attributed to the anger of the spirit. Among the Northern Bakweri, the association of spirits with the mountain could also be explained in terms of the importance of the mountain to the people. Most of their farming and hunting is done on the Mountain. Some forest products, for instance, wood for building and furniture is obtained from the forest of the mountain; this implies that the people rely on the Mountain for food, game and architecture/furniture etc. In addition, the eruption of the mountain is something which affects the people. It does not only destroy property, it frustrates people and takes away human lives when it occurs. Because of this economic importance of the Mountain and its unexpected and unwanted eruption, the tendency is to believe that it has some

  18. Volcanism on Mars. Chapter 41

    Science.gov (United States)

    Zimbelman, J. R.; Garry, W. B.; Bleacher, J. E.; Crown, D. A.

    2015-01-01

    Spacecraft exploration has revealed abundant evidence that Mars possesses some of the most dramatic volcanic landforms found anywhere within the solar system. How did a planet half the size of Earth produce volcanoes like Olympus Mons, which is several times the size of the largest volcanoes on Earth? This question is an example of the kinds of issues currently being investigated as part of the space-age scientific endeavor called "comparative planetology." This chapter summarizes the basic information currently known about volcanism on Mars. The volcanoes on Mars appear to be broadly similar in overall morphology (although, often quite different in scale) to volcanic features on Earth, which suggests that Martian eruptive processes are not significantly different from the volcanic styles and processes on Earth. Martian volcanoes are found on terrains of different age, and Martian volcanic rocks are estimated to comprise more than 50% of the Martian surface. This is in contrast to volcanism on smaller bodies such as Earth's Moon, where volcanic activity was mainly confined to the first half of lunar history (see "Volcanism on the Moon"). Comparative planetology supports the concept that volcanism is the primary mechanism for a planetary body to get rid of its internal heat; smaller bodies tend to lose their internal heat more rapidly than larger bodies (although, Jupiter's moon Io appears to contradict this trend; Io's intense volcanic activity is powered by unique gravitational tidal forces within the Jovian system; see "Volcanism on Io"), so that volcanic activity on Mars would be expected to differ considerably from that found on Earth and the Moon.

  19. Volcanic ash impacts on critical infrastructure

    Science.gov (United States)

    Wilson, Thomas M.; Stewart, Carol; Sword-Daniels, Victoria; Leonard, Graham S.; Johnston, David M.; Cole, Jim W.; Wardman, Johnny; Wilson, Grant; Barnard, Scott T.

    2012-01-01

    Volcanic eruptions can produce a wide range of hazards. Although phenomena such as pyroclastic flows and surges, sector collapses, lahars and ballistic blocks are the most destructive and dangerous, volcanic ash is by far the most widely distributed eruption product. Although ash falls rarely endanger human life directly, threats to public health and disruption to critical infrastructure services, aviation and primary production can lead to significant societal impacts. Even relatively small eruptions can cause widespread disruption, damage and economic loss. Volcanic eruptions are, in general, infrequent and somewhat exotic occurrences, and consequently in many parts of the world, the management of critical infrastructure during volcanic crises can be improved with greater knowledge of the likely impacts. This article presents an overview of volcanic ash impacts on critical infrastructure, other than aviation and fuel supply, illustrated by findings from impact assessment reconnaissance trips carried out to a wide range of locations worldwide by our international research group and local collaborators. ‘Critical infrastructure’ includes those assets, frequently taken for granted, which are essential for the functioning of a society and economy. Electricity networks are very vulnerable to disruption from volcanic ash falls. This is particularly the case when fine ash is erupted because it has a greater tendency to adhere to line and substation insulators, where it can cause flashover (unintended electrical discharge) which can in turn cause widespread and disruptive outages. Weather conditions are a major determinant of flashover risk. Dry ash is not conductive, and heavy rain will wash ash from insulators, but light rain/mist will mobilise readily-soluble salts on the surface of the ash grains and lower the ash layer’s resistivity. Wet ash is also heavier than dry ash, increasing the risk of line breakage or tower/pole collapse. Particular issues for water

  20. Volcanic Ash Nephelometer Probe Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced dropsondes that could effectively be guided through atmospheric regions of interest such as volcanic plumes may enable unprecedented observations of...

  1. Compatibility of Schistosoma mansoni Cameroon and Biomphalaria pfeifferi Senegal.

    Science.gov (United States)

    Southgate, V R; Tchuenté, L A; Théron, A; Jourdane, J; Ly, A; Moncrieff, C B; Gryseels, B

    2000-11-01

    The vectorial capacity of Biomphalaria pfeifferi from Ndiangue, Senegal, was investigated with an allopatric isolate of Schistosoma mansoni from Nkolbisson, Cameroon. The snail infection rate after exposure to a single miracidium per snail (MD1) was 56. 3 %, and 91.6%, for snails exposed to 5 miracidia per snail (MD5). The minimum pre-patent period was 21 days. The mean total cercarial production for the MDI group was 18,511 cercariae per snail, and 9757 cercariae for the MD5 group. The maximum production of cercariae for 1 day was 4892 observed in a snail from the MDI group at day 43 post-infection. The mean longevity of snails was higher in group MD1 (88 days p.i.) than in group MD5 (65 days p.i.). The chronobiological emergence pattern revealed a circadian rhythm with one shedding peak at mid-day. Comparisons are made with the vectorial capacity of the sympatric combination of B. pfeifferi Senegal/S. mansoni Senegal.

  2. Seroprevalence of Toxoplasma gondii infection among pregnant women in Cameroon

    Directory of Open Access Journals (Sweden)

    Anna L. Njunda

    2011-09-01

    Full Text Available Toxoplasmosis is caused by an intracellular protozoan, Toxoplasma gondii, which has a wide geographical distribution. The congenital form results in a gestational form that can present a temporary parasiteamia that will infect the fetus. For this reason early diagnosis in pregnancy is highly desirable, allowing prompt intervention in cases of infection. The aim of this study was to determine the seroprevalence of Toxoplasma gondii antibodies among pregnant women attending the Douala General Hospital. The study was carried out between March and July 2009, whereby 110 pregnant women were tested for IgG and IgM antibodies and information about eating habits and hygienic conditions was collected using a questionnaire. These women’s ages ranged from 20-44 years old with an average of 29.9 years; the overall IgG and IgM seroprevalence was 70% and 2.73 % respectively. Seroprevalence was significantly high amongst women who ate raw vegetables (76.39%, P<0.05 and there was a significant trend towards a higher seroprevalence in women who did not have a good source of water (75.58%, P<0.05. This research showed that consumption raw vegetables and poor quality drinking water are two risk factors associated with Toxoplasma gondii infection amongst pregnant women attending the Douala General Hospital in Cameroon.

  3. Indigenous Methods in Preserving Bush Mango Kernels in Cameroon

    Directory of Open Access Journals (Sweden)

    Zac Tchoundjeu

    2005-01-01

    Full Text Available Traditional practices for preserving Irvingia wombolu and Irvingia gabonensis (bush mango kernels were assessed in a survey covering twelve villages (Dongo, Bouno, Gribi [East], Elig-Nkouma, Nkom I, Ngoumou [Centre], Bidjap, Nko’ovos, Ondodo [South], Besong-Abang, Ossing and Kembong [Southwest], in the humid lowland forest zone of Cameroon. All the interviewed households that own trees of species were found to preserve kernels in periods of abundance, excluding Elig-Nkouma (87.5%. Eighty nine and 85% did so in periods of scarcity for I. wombolu and I. gabonensis respectively. Seventeen and twenty-nine kernel preservation practices were recorded for I. wombolu and I. gabonensis respectively. Most were based on continuous heating of the kernels or kernel by-products (cakes. The most commonly involved keeping the sun-dried kernels in a plastic bag on a bamboo rack hung above the fireplace in the kitchen. A 78% of interviews households reported preserving I. wombolu kernels for less than one year while 22% preserved it for more than one year with 1.9% for two years, the normal length of the off-season period for trees in the wild. Cakes wrapped with leaves and kept on a bamboo rack hung over the fireplace were reported by households in the East and South provinces to store Irvingia gabonensis longer (more than one year. Further studies on the utilization of heat for preserving and canning bush mango kernels are recommended.

  4. Volcanic Eruptions and Climate

    Science.gov (United States)

    Robock, A.

    2012-12-01

    Large volcanic eruptions inject sulfur gases into the stratosphere, which convert to sulfate aerosols with an e-folding residence time of about one year. The radiative and chemical effects of these aerosol clouds produce responses in the climate system. Observations and numerical models of the climate system show that volcanic eruptions produce global cooling and were the dominant natural cause of climate change for the past millennium, on timescales from annual to century. Major tropical eruptions produce winter warming of Northern Hemisphere continents for one or two years, while high latitude eruptions in the Northern Hemisphere weaken the Asian and African summer monsoon. The Toba supereruption 74,000 years ago caused very large climate changes, affecting human evolution. However, the effects did not last long enough to produce widespread glaciation. An episode of four large decadally-spaced eruptions at the end of the 13th century C.E. started the Little Ice Age. Since the Mt. Pinatubo eruption in the Philippines in 1991, there have been no large eruptions that affected climate, but the cumulative effects of small eruptions over the past decade had a small effect on global temperature trends. The June 13, 2011 Nabro eruption in Eritrea produced the largest stratospheric aerosol cloud since Pinatubo, and the most of the sulfur entered the stratosphere not by direct injection, but by slow lofting in the Asian summer monsoon circulation. Volcanic eruptions warn us that while stratospheric geoengineering could cool the surface, reducing ice melt and sea level rise, producing pretty sunsets, and increasing the CO2 sink, it could also reduce summer monsoon precipitation, destroy ozone, allowing more harmful UV at the surface, produce rapid warming when stopped, make the sky white, reduce solar power, perturb the ecology with more diffuse radiation, damage airplanes flying in the stratosphere, degrade astronomical observations, affect remote sensing, and affect

  5. Seasonal pattern of hospitalization from acute respiratory infections in Yaoundé, Cameroon.

    Science.gov (United States)

    Tchidjou, Hyppolite Kuekou; Vescio, Fenicia; Boros, Stefano; Guemkam, Georgette; Minka, Esthelle; Lobe, Monny; Cappelli, Giulia; Colizzi, Vittorio; Tietche, Felix; Rezza, Giovanni

    2010-10-01

    Acute respiratory infections (ARIs) are among the leading causes of childhood morbidity and mortality in Africa. The effects of climatic factors on occurrence of ARIs in the tropics are not clear. During the years 2006-07, we reviewed the clinical registers of the Chantal Biya Foundation (CBF), Yaoundé, Cameroon, paediatric hospital to investigate the association between climatic factors and ARIs in children. Our findings show that rain, high relative humidity and low temperatures are directly associated with an increase in the frequency of hospitalization from ARIs. Given the high frequency of hospitalization from ARIs we suggest that influenza vaccination campaigns should be implemented taking into account the seasonality in Cameroon.

  6. System of Volcanic activity

    Directory of Open Access Journals (Sweden)

    P. HÉDERVARI

    1972-06-01

    Full Text Available A comparison is made among the systems of B. G.
    Escher (3, of R. W. van Bemmelen (1 and that of the author (4. In this
    connection, on the basis of Esclier's classification, the terms of "constructiv
    e " and "destructive" eruptions are introduced into the author's system and
    at the same time Escher's concept on the possible relation between the depth
    of magma-chamber and the measure of the gas-pressure is discussed briefly.
    Three complementary remarks to the first paper (4 011 the subject of system
    of volcanic activity are added.

  7. Uranium series, volcanic rocks

    Science.gov (United States)

    Vazquez, Jorge A.

    2014-01-01

    Application of U-series dating to volcanic rocks provides unique and valuable information about the absolute timing of crystallization and differentiation of magmas prior to eruption. The 238U–230Th and 230Th-226Ra methods are the most commonly employed for dating the crystallization of mafic to silicic magmas that erupt at volcanoes. Dates derived from the U–Th and Ra–Th methods reflect crystallization because diffusion of these elements at magmatic temperatures is sluggish (Cherniak 2010) and diffusive re-equilibration is insignificant over the timescales (less than or equal to 10^5 years) typically associated with pre-eruptive storage of nearly all magma compositions (Cooper and Reid 2008). Other dating methods based on elements that diffuse rapidly at magmatic temperatures, such as the 40Ar/39Ar and (U–Th)/He methods, yield dates for the cooling of magma at the time of eruption. Disequilibrium of some short-lived daughters of the uranium series such as 210Po may be fractionated by saturation of a volatile phase and can be employed to date magmatic gas loss that is synchronous with volcanic eruption (e.g., Rubin et al. 1994).

  8. Volcan Reventador's Unusual Umbrella

    Science.gov (United States)

    Chakraborty, P.; Gioia, G.; Kieffer, S. W.

    2005-12-01

    In the past two decades, field observations of the deposits of volcanoes have been supplemented by systemmatic, and sometimes, opportunistic photographic documentation. Two photographs of the umbrella of the December 3, 2002 eruption of Volcan Reventador, Ecuador, reveal a prominently scalloped umbrella that is unlike any umbrella previously documented on a volcanic column. The material in the umbrella was being swept off a descending pyroclastic flow, and was, therefore, a co-ignimbrite cloud. We propose that the scallops are the result of a turbulent Rayleigh-Taylor (RT) instability with no precedents in volcanology. We ascribe the rare loss of buoyancy that drives this instability to the fact that the Reventador column fed on a cool co-ignimbrite cloud. On the basis of the observed wavelength of the scallops, we estimate a value for the eddy viscosity of the umbrella of 4000 ~m2/s. This value is consistent with a previously obtained lower bound (200 ~m2/s, K. Wohletz, priv. comm., 2005). We do not know the fate of the material in the umbrella subsequent to the photos. The analysis suggests that the umbrella was negatively buoyant. Field work on the co-ignimbrite deposits might reveal whether or not the material reimpacted, and if so, where and whether or not this material was involved in the hazardous flows that affected the main oil pipeline across Ecuador.

  9. Volcanic Eruptions and Climate

    Science.gov (United States)

    LeGrande, Allegra N.; Anchukaitis, Kevin J.

    2015-01-01

    Volcanic eruptions represent some of the most climatically important and societally disruptive short-term events in human history. Large eruptions inject ash, dust, sulfurous gases (e.g. SO2, H2S), halogens (e.g. Hcl and Hbr), and water vapor into the Earth's atmosphere. Sulfurous emissions principally interact with the climate by converting into sulfate aerosols that reduce incoming solar radiation, warming the stratosphere and altering ozone creation, reducing global mean surface temperature, and suppressing the hydrological cycle. In this issue, we focus on the history, processes, and consequences of these large eruptions that inject enough material into the stratosphere to significantly affect the climate system. In terms of the changes wrought on the energy balance of the Earth System, these transient events can temporarily have a radiative forcing magnitude larger than the range of solar, greenhouse gas, and land use variability over the last millennium. In simulations as well as modern and paleoclimate observations, volcanic eruptions cause large inter-annual to decadal-scale changes in climate. Active debates persist concerning their role in longer-term (multi-decadal to centennial) modification of the Earth System, however.

  10. Terrestrial volcanism in space and time

    Science.gov (United States)

    Simkin, Tom

    1993-01-01

    A survey is presented of current volcanic activity around the world and of dated volcanism over the past 10,000 yrs. The patterns in the data are described. The hazard presented by volcanism is briefly examined.

  11. Submarine Volcanic Morphology of Santorini Caldera, Greece

    Science.gov (United States)

    Nomikou, P.; Croff Bell, K.; Carey, S.; Bejelou, K.; Parks, M.; Antoniou, V.

    2012-04-01

    Santorini volcanic group form the central part of the modern Aegean volcanic arc, developed within the Hellenic arc and trench system, because of the ongoing subduction of the African plate beneath the European margin throughout Cenozoic. It comprises three distinct volcanic structures occurring along a NE-SW direction: Christianna form the southwestern part of the group, Santorini occupies the middle part and Koloumbo volcanic rift zone extends towards the northeastern part. The geology of the Santorini volcano has been described by a large number of researchers with petrological as well as geochronological data. The offshore area of the Santorini volcanic field has only recently been investigated with emphasis mainly inside the Santorini caldera and the submarine volcano of Kolumbo. In September 2011, cruise NA-014 on the E/V Nautilus carried out new surveys on the submarine volcanism of the study area, investigating the seafloor morphology with high-definition video imaging. Submarine hydrothermal vents were found on the seafloor of the northern basin of the Santorini caldera with no evidence of high temperature fluid discharges or massive sulphide formations, but only low temperature seeps characterized by meter-high mounds of bacteria-rich sediment. This vent field is located in line with the normal fault system of the Kolumbo rift, and also near the margin of a shallow intrusion that occurs within the sediments of the North Basin. Push cores have been collected and they will provide insights for their geochemical characteristics and their relationship to the active vents of the Kolumbo underwater volcano. Similar vent mounds occur in the South Basin, at shallow depths around the islets of Nea and Palaia Kameni. ROV exploration at the northern slopes of Nea Kameni revealed a fascinating underwater landscape of lava flows, lava spines and fractured lava blocks that have been formed as a result of 1707-1711 and 1925-1928 AD eruptions. A hummocky topography at

  12. Friction in volcanic environments

    Science.gov (United States)

    Kendrick, Jackie E.; Lavallée, Yan

    2016-04-01

    Volcanic landscapes are amongst the most dynamic on Earth and, as such, are particularly susceptible to failure and frictional processes. In rocks, damage accumulation is frequently accompanied by the release of seismic energy, which has been shown to accelerate in the approach to failure on both a field and laboratory scale. The point at which failure occurs is highly dependent upon strain-rate, which also dictates the slip-zone properties that pertain beyond failure, in scenarios such as sector collapse and pyroclastic flows as well as the ascent of viscous magma. High-velocity rotary shear (HVR) experiments have provided new opportunities to overcome the grand challenge of understanding faulting processes during volcanic phenomena. Work on granular ash material demonstrates that at ambient temperatures, ash gouge behaves according to Byerlee's rule at low slip velocities, but is slip-weakening, becoming increasingly lubricating as slip ensues. In absence of ash along a slip plane, rock-rock friction induces cataclasis and heating which, if sufficient, may induce melting (producing pseudotachylyte) and importantly, vesiculation. The viscosity of the melt, so generated, controls the subsequent lubrication or resistance to slip along the fault plane thanks to non-Newtonian suspension rheology. The shear-thinning behaviour and viscoelasticity of frictional melts yield a tendency for extremely unstable slip, and occurrence of frictional melt fragmentation. This velocity-dependence acts as an important feedback mechanism on the slip plane, in addition to the bulk composition, mineralogy and glass content of the magma, that all influence frictional behaviour. During sector collapse events and in pyroclastic density currents it is the frictional properties of the rocks and ash that, in-part, control the run-out distance and associated risk. In addition, friction plays an important role in the eruption of viscous magmas: In the conduit, the rheology of magma is integral

  13. Changes in lion (Panthera leo) home range size in Waza National Park, Cameroon

    NARCIS (Netherlands)

    Tumenta, P.N.; Van't Zelfde, M.; Croes, B.M.; Buij, R.; Funston, P.J.; Haes, de H.A.U.; longh, De H.H.

    2013-01-01

    The spatial ecology of Africa lions (Panthera leo) was studied from 2007 to 2009 in Waza National Park, Cameroon, by equipping individual lions with GPS/VHF radio-collars. Mean home range estimates using 100% minimum convex polygons (MCP) and 95% kernel-density estimation (KDE) were respectively 101

  14. Technical and Vocational Education in Cameroon and Critical Avenues for Development

    Science.gov (United States)

    Che, S. Megan

    2007-01-01

    Technical and vocational education (TVE) can influence development and economic progress for post-colonial societies. Some newly independent sub-Saharan African countries attempted curricular transformation that might produce a skilled workforce through widespread access to versions of TVE. In Cameroon, no such post-colonial curricular revolution…

  15. Habitat and diversity of ectomycorrhizal fungi in forests of South Cameroon

    NARCIS (Netherlands)

    Onguene, N.A.; Kuyper, T.W.

    2012-01-01

    Information is lacking on habitat and diversity of ectomycorrhizal (ECM) fungi of African humid forests. For three years, mushroom excursions were carried out in four sites with contrasted soil and altitude characteristics of South Cameroon, during wet seasons. Collected fungi were described in fres

  16. Striga infestation in northern Cameroon: Magnitude, dynamics and implications for managament

    NARCIS (Netherlands)

    Ayongwa, G.C.; Stomph, T.J.; Hoevers, R.; Ngoumou, T.N.; Kuyper, T.W.

    2010-01-01

    Surveys of Striga (S. hermonthica (Del.) Benth.) infestation in northern Cameroon over the period 1987–2005 assessed Striga dynamics and evaluated its control strategies. In that period the percentage of Striga-infested fields increased in North and Far-North Provinces. Striga incidence increased mo

  17. Fish Pond Aquaculture in Cameroon: A Field Survey of Determinants for Farmers' Adoption Behaviour

    Science.gov (United States)

    Ndah, Hycenth Tim; Knierim, Andrea; Ndambi, Oghaiki Asaah

    2011-01-01

    Although fish farming in Cameroon started in the late 1940s, currently the country meets only half of its domestic demand for fish. This article examines the complex issue of farmers' adoption decisions and attempts to answer why there is a lag in the diffusion process. The theory of behaviour modification and key variables of adoption form the…

  18. Distribution, incidence and abundance of the cassava brown root scale insect, Stictococcus vayssierei, in Cameroon

    NARCIS (Netherlands)

    Tchuanyo, M.; Huis, van A.; Lenteren, van J.C.

    2000-01-01

    A new scale insect, Stictococcus vayssierei, has been found attacking all the underground parts of cassava. From surveys in all the cassava-growing areas of Cameroon, the insect seems to be limited to the southern part of the country, where it is a major pest of cassava. This is the semi-humid zone

  19. Improving the benefits of wildlife harvesting in Northern Cameroon: a co-management perspective

    NARCIS (Netherlands)

    Mayaka, T.; Hendricks, T.; Wesseler, J.H.H.; Prins, H.H.T.

    2005-01-01

    We examined ways of improving the incentive structure of a safari company, the state, and the local communities within a wildlife co-management framework in Northern Cameroon. To this end, we built an integer linear programming model with state-allocated quotas and a profit maximisation objective fu

  20. How to win a football match in Cameroon : an anthropological study of Africa's most popular sport

    NARCIS (Netherlands)

    Pannenborg, A.

    2008-01-01

    Footballers Essomba and Ashu, team manager Kalla and spiritual adviser Zé are the key characters in this anthropological study of football in Cameroon, which is based on research carried out in 2003. It might seem that a well-organized club with professional executives, a team of talented players an

  1. Vulnerability, forest-related sectors and climate change adaptation : the case of Cameroon

    NARCIS (Netherlands)

    Sonwa, D.J.; Somorin, O.A.; Jum, C.; Bele, M.Y.; Nkem, J.N.

    2012-01-01

    In Cameroon and elsewhere in the Congo Basin, the majority of rural households and a large proportion of urban households depend on plant and animal products from the forests to meet their nutritional, energy, cultural and medicinal needs. This paper explores the likely impacts of climate-induced ch

  2. Knowledge, Attitudes and Practices towards Malaria in Mbonge and Kumba Sub-divisions in Cameroon

    NARCIS (Netherlands)

    Makoge, Valerie; Maat, Harro; Edward, Ndzi; Emery, Jerry

    2016-01-01

    Aims: To assess knowledge, attitudes and practices regarding transmission, prevention and treatment of malaria in four rural settings and one urban neighborhood. Study Design: Cross-sectional descriptive survey carried out in Cameroon. Place and Duration of Study: This study took place in rural Mbon

  3. Privatisation of agro-industrial parastatals and anglophone opposition in Cameroon

    NARCIS (Netherlands)

    Konings, P.J.J.

    1996-01-01

    This article focuses on the regional anglophone opposition in Cameroon which arose after 15 July 1994, when the government was forced by international donors to announce the privatization of 15 public enterprises, notably in the transport and agroindustrial sectors. The most prominent among them was

  4. Stress Management and Teachers' Productivity in Cameroon: Lessons from Momo Division

    Science.gov (United States)

    Anyi Einstein Moses E.

    2016-01-01

    A teacher who is stressed out, stresses out his student who in turn, behave differently (usually worse) and consequently produce more stress for the teacher. This study on Stress management and teachers' productivity was carried out in Momo Division North West Region of Cameroon. The aim was to find out the extent to which the teachers' acceptance…

  5. The Position of English Globally and Nationally: A Comparison of Cameroon and Vanuatu

    Science.gov (United States)

    Abongdia, Jane-Francis A.; Willans, Fiona

    2014-01-01

    This paper investigates language ideologies relevant to medium of instruction policy within two postcolonial countries: Cameroon and Vanuatu. Each country experienced British and French rule, and has retained both English and French as official languages and media of instruction. However, since Independence, there has been a difference in the way…

  6. Savannah Forest Beekeepers in Cameroon: Actions to Reduce Vulnerability. Chapter 7

    NARCIS (Netherlands)

    Ingram, V.J.

    2016-01-01

    The savannah forests in Adamaoua, Cameroon, are home to traditional, forest-based beekeepers, subsistence farmers and pastoralists. This sparsely populated region is economically marginal and little developed, with lower than national average incomes. Forest apiculture is important here: honey, bees

  7. Nutrient flows in smallholder production systems in the humid forest zone of southern Cameroon

    NARCIS (Netherlands)

    Kanmegne, J.; Smaling, E.M.A.; Brussaard, L.; Gansop-Kouomegne, A.; Boukung, A.

    2006-01-01

    The flows and balances of N, P and K were studied in 20 farms in the Campo Ma'an area in Cameroon between March and August 2002 to assess the nutrient dynamics in smallholder farms. Data were collected through farmer interviews, field measurements and estimates from transfer functions. Nutrient inpu

  8. Bridging the gap: how traditional healers interact with their patients. A comparative study in Cameroon.

    NARCIS (Netherlands)

    Labhardt, N.D.; Aboa, S.M.; Manga, E.; Bensing, J.M.; Langewitz, W.

    2010-01-01

    Objective: To compare traditional healers (TH) and Cameroonian representatives of Western medicine (Western providers (WP)) in terms of patient characteristics and communication patterns during the consultation in rural Cameroon. Methods: A facility-based comparative study was conducted. Seven TH we

  9. Phytochemical analysis and biological evaluation of selected African propolis samples from Cameroon and Congo

    NARCIS (Netherlands)

    Papachroni, D.; Graikou, K.; Kosalec, I.; Damianakos, H.; Ingram, V.J.; Chinou, I.

    2015-01-01

    The objective of this study was the chemical analysis of four selected samples of African propolis (Congo and Cameroon) and their biological evaluation. Twenty-one secondary metabolites belonging to four different chemical groups were isolated from the 70% ethanolic extracts of propolis and their st

  10. Plasmodium falciparum transmission blocking immunity under conditions of low and high endemicity in Cameroon.

    NARCIS (Netherlands)

    Boudin, C.; Kolk, M. van der; Tchuinkam, T.; Gouagna, C.; Bonnet, S.; Safeukui, I.; Mulder, B.J.M.; Meunier, J.Y.; Verhave, J.P.

    2004-01-01

    Transmission blocking immunity (TBI) was studied in relation to age, gametocyte density and transmission intensity. subjects with high gametocytaemias were selected in a hypo-endemic urban district and a hyper-endemic rural area in South Cameroon. TBI was determined in blood from gametocyte carriers

  11. Lolodorfus, a new genus of net-winged beetles (Coleoptera: Lycidae: Dexorinae) from Cameroon.

    Science.gov (United States)

    Bocakova, Milada

    2014-06-04

    A new genus Lolodorfus is proposed within the subfamily Dexorinae and Lolodorfus flavus sp. nov. from Cameroon is described. Illustrations of diagnostic characters are given. The genus Mimolibnetis Pic, 1936 is transferred to the Dexorinae Bocak et Bocakova, 1989, and consequently the subfamily Mimolibnetinae Kazantsev, 2013 is considered to be a younger synonym of Dexorinae Bocak et Bocakova, 1989.

  12. The politics of neoliberal reforms in Africa : State and civil society in Cameroon

    NARCIS (Netherlands)

    Konings, P.J.J.

    2011-01-01

    Neoliberalism has become the dominant development agenda in Africa, but neoliberal experiments have displayed a remarkable diversity in different countries. This book focuses on Cameroon, where the neoliberal project has been influenced by the nation's complex economic and political history. Current

  13. Determinants and Impacts Of Human Mobility Dynamics In The Western Highlands Of Cameroon

    NARCIS (Netherlands)

    Tankou, C.M.; Iongh, de H.H.; Persoon, G.; Bruijn, de M.E.; Snoo, de G.R.

    2014-01-01

    This study analyses human mobility among inhabitants of Cameroon‘s most populous region, the Western Highlands of Cameroon. In other to capture the impact of various determinants on human mobility, a comparative study was conducted through household and field surveys in three villages in the region

  14. Teaching Practice in Cameroon: The Effectiveness of the University of Buea Model and Implications for Quality

    Science.gov (United States)

    Endeley, Margaret Nalova

    2014-01-01

    The paper aimed at assessing the effectiveness of the teaching practice model in the University of Buea, which is different from that of other teacher education institutions in Cameroon. Teaching Practice is an important component of a teacher education programme and the quality of supervision and duration are key in achieving effectiveness which…

  15. The emotional world of kinship: Children's experiences of fosterage in East Cameroon

    NARCIS (Netherlands)

    Notermans, C.D.

    2008-01-01

    This article focuses on children's narrated experiences of fosterage in East Cameroon. It seeks to complement the predominantly adult approaches to fosterage with children's views of the intimate, emotional and competitive aspects of kinship in everyday life. As kinship evolves in homes through shar

  16. Buruli Ulcer in Cameroon: The Development and Impact of the National Control Programme.

    Directory of Open Access Journals (Sweden)

    Earnest Njih Tabah

    2016-01-01

    Full Text Available Cameroon is endemic for Buruli ulcer (BU and organised institutional BU control began in 2002. The objective was to describe the evolution, achievements and challenges of the national BU control programme (NBUCP and to make suggestions for scaling up the programme.We analysed collated data on BU from 2001 to 2014 and reviewed activity reports NBUCP in Cameroon. Case-detection rates and key BU control indicators were calculated and plotted on a time scale to determine trends in performance. A linear regression analysis of BU detection rate from 2005-2014 was done. The regression coefficient was tested statistically for the significance in variation of BU detection rate.In 14 years of BU control, 3700 cases were notified. The BU detection rate dropped significantly from 3.89 to 1.45 per 100 000 inhabitants. The number of BU endemic health districts rose from two to 64. Five BU diagnostic and treatment centres are functional and two more are planned for 2015. The health system has been strengthened and BU research and education has gained more interest in Cameroon.Although institutional BU control Cameroon only began 30 years after the first cases were reported in 1969, a number of milestones have been attained. These would serve as stepping stones for charting the way forward and improving upon control activities in the country if the major challenge of resource allocation is dealt with.

  17. Perils to pregnancies: On social sorrows and strategies surrounding pregnancy loss in Cameroon

    NARCIS (Netherlands)

    Sijpt, E. van der; Notermans, C.D.

    2010-01-01

    This article explores the local perceptions and practices surrounding pregnancy loss in Cameroon-a topic that has long been neglected in international reproductive health debates. Based on extended periods of anthropological fieldwork in an urban and a rural setting in the East province of the count

  18. Volcanic studies at Katmai

    Energy Technology Data Exchange (ETDEWEB)

    1989-12-31

    The Continental Scientific Drilling Program (CSDP) is a national effort supported by the Department of Energy, the US Geological Survey, and the National Science Foundation. One of the projects proposed for the CSDP consists of drilling a series of holes in Katmai National Park in Alaska to give a third dimension to the model of the 1912 eruption of Novarupta, and to investigate the processes of explosive volcanism and hydrothermal transport of metals (Eichelberger et al., 1988). The proposal for research drilling at Katmai states that ``the size, youth, elevated temperature, and simplicity of the Novarupta vent make it a truly unique scientific target.`` The National Park Service (NPS), which has jurisdiction, is sympathetic to aims of the study. However, NPS wishes to know whether Katmai is indeed uniquely suited to the research, and has asked the Interagency Coordinating Group to support an independent assessment of this claim. NPS suggested the National Academy of Sciences as an appropriate organization to conduct the assessment. In response, the National Research Council -- the working arm of the Academy -- established, under the aegis of its US Geodynamics Committee, a panel whose specific charge states: ``The proposed investigation at Katmai has been extensively reviewed for scientific merit by the three sponsoring and participating agencies. Thus, the scientific merit of the proposed drilling at Katmai is not at issue. The panel will review the proposal for scientific drilling at Katmai and prepare a short report addressing the specific question of the degree to which it is essential that the drilling be conducted at Katmai as opposed to volcanic areas elsewhere in the world.``

  19. Quaternary basaltic volcanism in the Payenia volcanic province, Argentina

    DEFF Research Database (Denmark)

    Søager, Nina

    The extensive Quaternary volcanism in the Payenia volcanic province, Mendoza, Argentina, is investigated in this study by major and trace element analyses, Sr, Nd, Hf and Pb-isotopic analyses and Zr-Hf isotope dilution data on samples from almost the entire province. The samples are mainly...... in basalts from all the studied volcanic fields in Payenia is signs of lower crustal contamination indicating assimilation of, in some cases, large amounts of trace element depleted, mafic, plagioclase-bearing rocks. The northern Payenia is dominated by backarc basalts erupted between late Pliocene to late...

  20. Prevalence and causes of blindness at a tertiary hospital in Douala, Cameroon

    Directory of Open Access Journals (Sweden)

    Eballé AO

    2011-09-01

    Full Text Available André Omgbwa Eballé1,4, Côme Ebana Mvogo1,3, Godefroy Koki2, Nyouma Mounè3, Cyrille Teutu5, Augustin Ellong2,3, Assumpta Lucienne Bella2,41Faculty of Medicine and Pharmaceutical Sciences, University of Douala, Douala, Cameroon; 2Faculty of Medicine and Biomedical Sciences, University of Yaoundé I, Yaoundé, Cameroon; 3General Hospital of Douala, Ophthalmology Unit, Douala, Cameroon; 4Cameroon National Blindness Control Programme, Ministry of Public Health, Yaoundé, Cameroon; 5Higher Institute of Health Sciences, Mountain University, Banganté, CameroonPurpose: The aim of this study was to determine the prevalence and causes of bilateral and unilateral blindness in the town of Douala and its environs based on data from the ophthalmic unit of a tertiary hospital in Douala.Methods: We conducted a retrospective epidemiological survey of consultations at the eye unit of the Douala General Hospital over the last 20 years (from January 1, 1990 to December 31, 2009.Results: Out of the 1927 cases of blindness, 1000 were unilateral, corresponding to a hospital prevalence of 1.84% and 927 cases were bilateral, corresponding to a hospital prevalence of 1.71%. No statistically significant difference was noted between the two (P = 0.14. The leading causes of bilateral blindness were cataract (50.1%, glaucoma (19.7%, and diabetic retinopathy (7.8% while the leading causes of unilateral blindness were cataract (40.4%, glaucoma (14.1%, and retinal detachment (9.1%. Cataract (51.2%, cortical blindness (16.3%, and congenital glaucoma (10% were the leading causes of bilateral blindness in children aged less than 10 years.Conclusion: Blindness remains a public health problem in the Douala region with a hospital prevalence which is relatively higher than the national estimate given by the National Blindness Control Program.Keywords: bilateral blindness, unilateral blindness, prevalence, Douala, Cameroon

  1. Access to potable water and sanitation in Cameroon within the context of Millennium Development Goals (MDGS).

    Science.gov (United States)

    Ako, Andrew Ako; Shimada, Jun; Eyong, Gloria Eneke Takem; Fantong, Wilson Yetoh

    2010-01-01

    Cameroon has been fully engaged with the Millennium Development Goals (MDGs) since their inception in 2000. This paper examines the situation of access to potable water and sanitation in Cameroon within the context of the Millennium Development Goals (MDGs), establishes whether Cameroon is on the track of meeting the MDGs in these domains and proposes actions to be taken to bring it closer to these objectives. Based on analyzed data obtained from national surveys, government ministries, national statistical offices, bibliographic research, reports and interviews, it argues that Cameroon will not reach the water and sanitation MGDs. While Cameroon is not yet on track to meet the targets of the MDGs for water and sanitation, it has made notable progress since 1990, much more needs to be done to improve the situation, especially in rural areas. In 2006, 70% of the population had access to safe drinking water and the coverage in urban centres is 88%, significantly better than the 47% in rural areas. However, rapid urbanization has rendered existing infrastructure inadequate with periurban dwellers also lacking access to safe drinking water. Sanitation coverage is also poor. In urban areas only 58% of the population has access to improved sanitation facilities, and the rate in rural areas is 42%. Women and girls shoulder the largest burden in collecting water, 15% of urban and 18% rural populations use improved drinking water sources over 30 minutes away. Cameroon faces the following challenges in reaching the water and sanitation MDGs: poor management and development of the resources, coupled with inadequate political will and commitment for the long term; rapid urbanization; urban and rural poverty and regulation and legislative lapses. The authors propose that: bridging the gap between national water policies and water services; recognizing the role played by Civil Society Organizations (CSOs) in the attainment of MDGs; developing a Council Water Resource Management

  2. A Critical Appraisal of the Juvenile Justice System under Cameroon's 2005 Criminal Procedure Code: Emerging Challenges

    Directory of Open Access Journals (Sweden)

    S Tabe

    2012-03-01

    Full Text Available The objective of this article is to examine the changes introduced by the 2005 Cameroonian Criminal Procedure Code on matters of juvenile justice, considering that before this Code, juvenile justice in Cameroon was governed by extra-national laws. In undertaking this analysis, the article highlights the evolution of the administration of juvenile justice 50 years after independence of Cameroon. It also points out the various difficulties and shortcomings in the treatment of juvenile offenders in Cameroon since the enactment of the new Criminal Procedure Code. The article reveals that the 2005 Code is an amalgamation of all hitherto existing laws in the country that pertained to juvenile justice, and that despite the considerable amount of criticism it has received, the Code is clearly an improvement of the system of juvenile justice in Cameroon, since it represents a balance of the due process rights of young people, the protection of society and the special needs of young offenders. This is so because the drafters of the Code took a broad view of the old laws on juvenile justice. Also a wide range of groups were consulted, including criminal justice professionals, children’s service organisations, victims, parents, young offenders, educators, advocacy groups and social-policy analysts. However, to address the challenges that beset the juvenile justice system of Cameroon, the strategy of the government should be focussed on three areas: the prevention of youth crime, the provision of meaningful consequences for the actions of young people, and the rehabilitation and reintegration of young offenders. Cameroonian law should seek educative solutions rather than to impose prison sentences or other repressive measures on young offenders. Special courts to deal with young offenders should be established outside the regular penal system and should be provided with resources that are adequate for and appropriate to fostering their understanding of

  3. Current Status of HIV/AIDS in Cameroon: How Effective are Control Strategies?

    Directory of Open Access Journals (Sweden)

    Dora Mbanya

    2008-12-01

    Full Text Available Nearly three decades after its discovery, HIV infection remains the number one killer disease in Sub-Saharan Africa where up to 67% of the world’s 33 million infected people live. In Cameroon, based on a Demographic Health Survey carried out in 2004, the national HIV prevalence is estimated at 5.5% with women and youths being predominantly infected. Orphans and vulnerable children (OVC from the HIV and AIDS pandemic have increased steadily over the years; hospital occupancy is estimated at about 30%, hence stretching the health system; co-infections like HIV/tuberculosis have been reported to reach 40-50% of infected cases and 95% of teachers are said not to be productive on several counts. Thus, the impact is multi-sectorial. Furthermore, the HIV epidemic in Cameroon is peculiar because of the wide HIV-1 genetic diversity of HIV-1 Group M observed with several subtypes reported (A, B, C, D, F, G, H, J, K, predominantly subtype A. There are also circulating recombinant forms, mainly CRF02_AG. In addition, HIV-1 Groups O and N have all been noted in Cameroon. These findings have great implications not only for HIV diagnosis, but also for responsiveness to therapy as well as for vaccine development. In 1986, the initial response of the Cameroon government to the increasing trends in the HIV/AIDS infection was to create a National AIDS Control Committee to coordinate a national AIDS programme. By 2000, the first National Strategic Plan was drawn for 2000-2005. The second National Strategic Plan for 2006-2010 is currently being implemented and covers various axes. Some results obtained show that there has been significantly positive outcomes noted in the various arms of intervention by the Cameroon government.

  4. Current status of HIV/AIDS in Cameroon: how effective are control strategies?

    Science.gov (United States)

    Mbanya, Dora; Sama, Martyn; Tchounwou, Paul

    2008-12-01

    Nearly three decades after its discovery, HIV infection remains the number one killer disease in Sub- Saharan Africa where up to 67% of the world's 33 million infected people live. In Cameroon, based on a Demographic Health Survey carried out in 2004, the national HIV prevalence is estimated at 5.5% with women and youths being predominantly infected. Orphans and vulnerable children (OVC) from the HIV and AIDS pandemic have increased steadily over the years; hospital occupancy is estimated at about 30%, hence stretching the health system; co-infections like HIV/tuberculosis have been reported to reach 40-50% of infected cases and 95% of teachers are said not to be productive on several counts. Thus, the impact is multi-sectorial. Furthermore, the HIV epidemic in Cameroon is peculiar because of the wide HIV-1 genetic diversity of HIV-1 Group M observed with several subtypes reported (A, B, C, D, F, G, H, J, K), predominantly subtype A. There are also circulating recombinant forms, mainly CRF02_AG. In addition, HIV-1 Groups O and N have all been noted in Cameroon. These findings have great implications not only for HIV diagnosis, but also for responsiveness to therapy as well as for vaccine development. In 1986, the initial response of the Cameroon government to the increasing trends in the HIV/AIDS infection was to create a National AIDS Control Committee to coordinate a national AIDS programme. By 2000, the first National Strategic Plan was drawn for 2000-2005. The second National Strategic Plan for 2006-2010 is currently being implemented and covers various axes. Some results obtained show that there has been significantly positive outcomes noted in the various arms of intervention by the Cameroon government.

  5. Review: Meredith Terretta, Nation of Outlaws, State of Violence: Nationalism, Grassfields Tradition, and State Building in Cameroon (2013

    Directory of Open Access Journals (Sweden)

    Sebastian Elischer

    2015-01-01

    Full Text Available Review of the monograph:Meredith Terretta, Nation of Outlaws, State of Violence: Nationalism, Grassfields Tradition, and State Building in Cameroon, Athens: Ohio University Press, 2013, ISBN 978-0-8214-2069-0, 368 pp.

  6. Io. [theories concerning volcanic activity

    Science.gov (United States)

    Johnson, T. V.; Soderblom, L. A.

    1983-01-01

    A report on the continuing investigation of Io is presented. Gravitational resonance is discussed as the cause of Io's volcanism, and the volcanic activity is explained in terms of sulfur chemistry. Theories concerning the reasons for the two main types of volcanic eruptions on Io are advanced and correlated with geographical features of the satellite. The sulfur and silicate models of the calderas are presented, citing the strengths and weaknesses of each. Problems of the gravitational resonance theory of Io's heat source are then described. Finally, observations of Io planned for the Galileo mission are summarized.

  7. Aquaculture in Cameroon and potential of lactic acid bacteria to be used as diseases controlling agents. A Review

    OpenAIRE

    Kaktchan, Pierre Marie; Zambou Ngoufack, Francois; Fonteh Anyangwe, Florence; Perez-Chabela, M. Lourdes

    2015-01-01

    Aquaculture is the world’s fastest growing food production sector and can be a great solution to the massive demand for protein of animal due to increase in the Cameroonian population. This review summarizes the past and present status of fish aquaculture in Cameroon, the new challenges for intensifying fish production and evaluates the possibility of using lactic acid bacteria as disease control agents in order to overcome these challenges. Fish farming started in Cameroon in the late 1940s,...

  8. Intestinal Parasitic Infections in HIV Infected and Non-Infected Patients in a Low HIV Prevalence Region, West-Cameroon

    OpenAIRE

    2013-01-01

    The magnitude of intestinal parasitic infection in acquired immunodeficiency syndrome patients requires careful consideration in the developing world where poor nutrition is associated with poor hygiene and several tropical diseases. However, there have been very few studies addressing this issue in Cameroon. This study was conducted to determine the prevalence of intestinal parasitosis in HIV/AIDS patients in Dschang -Cameroon. Stool and blood specimens from HIV/AIDS patients and control gro...

  9. Public health implications of contamination of Franc CFA (XAF) circulating in Buea (Cameroon) with drug resistant pathogens

    OpenAIRE

    Akoachere, Jane-Francis Tatah Kihla; Gaelle, Nana; Dilonga, Henry Meriki; Nkuo-Akenji, Theresa K

    2014-01-01

    Background Studies in different parts of the world have implicated money as a vehicle for transmission of pathogens. Such information which is necessary to facilitate infection control strategies is lacking in many sub-Saharan countries including Cameroon. This study analyzed the Franc de la Communauté Financiere d’Afrique (Franc CFA), the currency used in Cameroon and other countries in the Central African sub-region, as a potential vehicle for transmission of pathogenic bacteria and fungi, ...

  10. Hawaii Volcanism: Lava Forms

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Over the last several million years the Hawaiian Islands have been built of successive lava flows. They are the most recent additions in a long line of volcanoes...

  11. Stress and Time Management Settings in University of Maroua, Cameroon

    Directory of Open Access Journals (Sweden)

    Joseph BESONG BESONG

    2015-06-01

    Full Text Available The aim of this paper is to examine stress and time in educational management in Maroua University. These two phenomena are profound in educational issues in Cameroon due to the complex administration or management. Education comprised of diversity of activities ranging from administration, discipline, teaching, evaluation and learning. Each of these activities requires time schedule to avoid stress in the face of pressure. Administration requires planning, organizing, controlling, commanding, coordinating, reporting and budgeting. Each of these managing variables requires time, just as discipline, teaching, evaluation and learning should need. The situation may be affected by higher authority interference and cause a rush thus affecting every schedule in the system on this note, it is necessary that every administrator on management cadre should develop a list of activities such as admissions, examinations, sports, vacations and other ceremonies which requires his attention on daily, weekly, or monthly bases and there after allocate in a tentative fashion the most appropriate times for dealing with such activities. Some profile recommendations are: strict adhering to schedules to avoid overlapping or prolongation to other programs; the schedules should be pasted or placed at a convenient point in the office for reference to avoid forgetfulness: as an administrator, time should be allocated for meeting or consulting with visitors and subordinates; he should delegate functions to his accredited subordinates to crave chance or time for essential duty; he should review the school or organization programs on daily, weekly or monthly bases the degree to which his administration goals have been attained and he (i.e. administrator should crave time for rest i.e. holidays, relaxation and various forms of physical exercises to revitalizes the body for subsequent activities. The paper recommends planning which is vital in management to avoid time waste

  12. Los volcanes y los hombres

    OpenAIRE

    García, Carmen

    2007-01-01

    Desde las entrañas de la tierra, los volcanes han creado la atmósfera, el agua de los océanos, y esculpido los relieves del planeta: son, pues, los zahoríes de la vida. Existen volcanes que los hombres explotan o cultivan, y otros sobre los cuales se han construido observatorios en los que se llevan a cabo avanzadas investigaciones científicas.

  13. Volcanic eruptions observed with infrasound

    Science.gov (United States)

    Johnson, Jeffrey B.; Aster, Richard C.; Kyle, Philip R.

    2004-07-01

    Infrasonic airwaves produced by active volcanoes provide valuable insight into the eruption dynamics. Because the infrasonic pressure field may be directly associated with the flux rate of gas released at a volcanic vent, infrasound also enhances the efficacy of volcanic hazard monitoring and continuous studies of conduit processes. Here we present new results from Erebus, Fuego, and Villarrica volcanoes highlighting uses of infrasound for constraining quantitative eruption parameters, such as eruption duration, source mechanism, and explosive gas flux.

  14. Volcanic hazards and aviation safety

    Science.gov (United States)

    Casadevall, Thomas J.; Thompson, Theodore B.; Ewert, John W.; ,

    1996-01-01

    An aeronautical chart was developed to determine the relative proximity of volcanoes or ash clouds to the airports and flight corridors that may be affected by volcanic debris. The map aims to inform and increase awareness about the close spatial relationship between volcanoes and aviation operations. It shows the locations of the active volcanoes together with selected aeronautical navigation aids and great-circle routes. The map mitigates the threat that volcanic hazards pose to aircraft and improves aviation safety.

  15. Effects of human presence on chimpanzee nest location in the Lebialem-Mone forest landscape, Southwest Region, Cameroon.

    Science.gov (United States)

    Last, Cadell; Muh, Bernice

    2013-01-01

    In several areas of Africa, great apes experience increasing predation pressure as a result of human activities. In this study, terrestrial and arboreal nest construction among chimpanzee (Pan troglodytes ellioti) populations was investigated in the Lebialem-Mone Forest Landscape (LMFL), Southwest Region, Cameroon, to examine the anthropogenic effects on nest location. Data on the height, distribution and approximate age of chimpanzee night nests were collected during two 4-week primate field surveys (July to August 2010; July 2011) at two field sites (Bechati and Andu) within the LMFL. Data were collected using the line transect method. Chimpanzee night nests were categorized by their location: arboreal versus terrestrial. During the two field surveys, arboreal night nests were the most frequently constructed nest type at both sites, and the only type of night nest constructed at Bechati. Terrestrial night nests were also constructed at Andu. The main difference between these two sites is the level of human predation and agricultural development. At Bechati chimpanzees inhabit forest regions around dense, expanding villages and are regularly hunted by humans. However, at Andu the chimpanzee populations are not under the same threat. Therefore, terrestrial night nest construction in the LMFL appears to be a behavior exhibited where there is less human presence.

  16. The simultaneous loop flow correction analysis in the water feed network of Minkok Edjombo (SOUTH –CAMEROON.

    Directory of Open Access Journals (Sweden)

    MENDOMO MEYE SERGES

    2014-11-01

    Full Text Available With increasing population growth and industrial development, water flow rates and other hydraulic requirements associated with water distribution systems have been estimated to increase both national and local scale. Water shortage will cause inconvenience to people’s life and it will impact city function and industrial production. Hence to overcome this problem design and analysis of water distribution system is necessary to get optimal discharge. In this paper a water pipeline network analysis with a case study of a small city (MinkokEdjombo in the southern Cameroon system has been undertaken. What prompted this study is that the case study has a lot of fluctuations in its head loss. Also, the discharge is not proportional to the pipe diameter. The study therefore adopted simultaneous loop flow correction method because it computes simultaneous flows corrections for all loops, hence, the best since computational procedures takes into account the iterative influence of flow corrections between loops which have common pipes. After applying the simultaneous loop flow correction analyze in a twenty-four sampled pipeline network, a drastic reduction in head loss and regular line along the axis was observed. Besides, the rate at which the water flows was observed to be proportional to the pipe diameter. Hence, the method is a useful aid in planning, designing and operating of reticulated pipeline network for higher efficiency and improved economy.

  17. Volcanic Zone, New Zealand

    Directory of Open Access Journals (Sweden)

    Graham J. Weir

    2001-01-01

    Full Text Available A conceptual model of the Taupo Volcanic Zone (TVZ is developed, to a depth of 25 km, formed from three constant density layers. The upper layer is formed from eruption products. A constant rate of eruption is assumed, which eventually implies a constant rate of extension, and a constant rate of volumetric creation in the middle and bottom layers. Tectonic extension creates volume which can accomodate magmatic intrusions. Spreading models assume this volume is distributed throughout the whole region, perhaps in vertical dykes, whereas rifting models assume the upper crust is thinned and the volume created lies under this upper crust. Bounds on the heat flow from such magmatic intrusions are calculated. Heat flow calculations are performed and some examples are provided which match the present total heat output from the TVZ of about 4200 MW, but these either have extension rates greater than the low values of about 8 ± 4 mm/a being reported from GPS measurements, or else consider extension rates in the TVZ to have varied over time.

  18. Low birth weight in perinatally HIV-exposed uninfected infants: observations in urban settings in Cameroon.

    Directory of Open Access Journals (Sweden)

    Casimir Ledoux Sofeu

    Full Text Available BACKGROUND: The consequences of maternal HIV infection for fetal growth are controversial. Here, we estimated the frequency of small for gestational age and gender (SGAG among neonates born to HIV-infected or uninfected mothers and assessed the contribution, if any, of maternal HIV to the risk of SGAG. METHODS: The data used were obtained from the ANRS-Pediacam cohort in Cameroon. Pairs of newborns, one to a HIV-infected mother and the other to an uninfected mother, were identified during the first week of life, and matched on gender and recruitment site from 2007-2010. SGAG was defined in line with international recommendations as a birth weight Z-score adjusted for gestational age at delivery and gender more than two standard deviations below the mean (-2SD. Considering the matched design, logistic regression modeling was adjusted on site and gender to explore the effect of perinatal HIV exposure on SGAG. RESULTS: Among the 4104 mother-infant pairs originally enrolled, no data on birth weight and/or gestational age were available for 108; also, 259 were twins and were excluded. Of the remaining 3737 mother-infant pairs, the frequency of SGAG was 5.3% (95%CI: 4.6-6.0, and was significantly higher among HIV-infected infants (22.4% vs. 6.3%; p<.001 and lower among HIV-unexposed uninfected infants (3.5% vs. 6.3%; p<.001 than among HIV-exposed uninfected infants. Similarly, SGAG was significantly more frequent among HIV-infected infants (aOR: 4.1; 2.0-8.1 and less frequent among HIV-unexposed uninfected infants (aOR: 0.5; 0.4-0.8 than among HIV-exposed uninfected infants. Primiparity (aOR: 1.9; 1.3-2.7 and the presence of any disease during pregnancy (aOR: 1.4; 1.0-2.0 were identified as other contributors to SGAG. CONCLUSION: Maternal HIV infection was independently associated with SGAG for HIV-exposed uninfected infants. This provides further evidence of the need for adapted monitoring of pregnancy in HIV-infected women, especially if they are

  19. Magma genesis of the acidic volcanism in the intra-arc rift zone of the Izu volcanic arc, Japan

    Science.gov (United States)

    Haraguchi, S.; Tokuyama, H.; Ishii, T.

    2010-12-01

    The Izu volcanic arc extends over 550 km from the Izu Peninsula, Japan, to the Nishinoshima Trough or Sofugan tectonic line. It is the northernmost segment of the Izu-Bonin-Mariana arc system, which is located at the eastern side of the Philippine Sea Plate. The recent magmatism of the Izu arc is bimodal and characterized by basalt and rhyolite (e.g. Tamura and Tatsumi 2002). In the southern Izu arc, volcanic front from the Aogashima to the Torishima islands is characterized by submarine calderas and acidic volcanisms. The intra-arc rifting, characterized by back-arc depressions, small volcanic knolls and ridges, is active in this region. Volcanic rocks were obtained in 1995 during a research cruise of the R/V MOANA WAVE (Hawaii University, cruise MW9507). Geochemical variation of volcanic rocks and magma genesis was studied by Hochstaedter et al. (2000, 2001), Machida et al (2008), etc. These studies focused magma and mantle dynamics of basaltic volcanism in the wedge mantle. Acidic volcanic rocks were also dredged during the curies MW9507. However, studies of these acidic volcanics were rare. Herein, we present petrographical and chemical analyses of these acidic rocks, and compare these results with those of other acidic rocks in the Izu arc and lab experiments, and propose a model of magma genesis in a context of acidic volcanism. Dredge sites by the cruise MW9507 are 120, and about 50 sites are in the rift zone. Recovered rocks are dominated by the bimodal assemblage of basalt-basaltic andesite and dacite-rhyolite. The most abundant phase is olivine basalt, less than 50 wt% SiO2. Andesites are minor in volume and compositional gap from 56 to 65 wt% SiO2 exists. The across-arc variation of the HFSE contents and ratios, such as Zr/Y and Nb/Zr of rhyolites exhibit depleted in the volcanic front side and enriched in reararc side. This characteristic is similar to basaltic volcanism pointed out by Hochstaedter et al (2000). The petrographical features of rhyolites

  20. Geochemical Characteristics of Danfeng Meta-Volcanic Rocks in Shangzhou Area,Shaanxi Province

    Institute of Scientific and Technical Information of China (English)

    1995-01-01

    The Danfeng meta-volcanics in the Shangzhou area, Shaanxi Province are characterized by oceanic island arc volcanic geochemistry. They are a suite of low-K tholeiitic series and calc-alkaline series meta-volcanic rocks derived from different sources respectively.These meta-volcanics have high Th/Ta ratios and low contents of Ni,Ta,Ti,Y and Yb, suggesting that they were influenced by the subduction zone components.Many lines of evidence show that the Danfeng meta-volcanics were produced in an oceanic island are setting of the supra-subduction zone at the southern margin of the North China Block during the Early Paleozoic.

  1. Communicating Uncertainty in Volcanic Ash Forecasts: Decision-Making and Information Preferences

    Science.gov (United States)

    Mulder, Kelsey; Black, Alison; Charlton-Perez, Andrew; McCloy, Rachel; Lickiss, Matthew

    2016-04-01

    The Robust Assessment and Communication of Environmental Risk (RACER) consortium, an interdisciplinary research team focusing on communication of uncertainty with respect to natural hazards, hosted a Volcanic Ash Workshop to discuss issues related to volcanic ash forecasting, especially forecast uncertainty. Part of the workshop was a decision game in which participants including forecasters, academics, and members of the Aviation Industry were given hypothetical volcanic ash concentration forecasts and asked whether they would approve a given flight path. The uncertainty information was presented in different formats including hazard maps, line graphs, and percent probabilities. Results from the decision game will be presented with a focus on information preferences, understanding of the forecasts, and whether different formats of the same volcanic ash forecast resulted in different flight decisions. Implications of this research will help the design and presentation of volcanic ash plume decision tools and can also help advise design of other natural hazard information.

  2. Biological Constraints in Tomato Production in the Western Highlands of Cameroon

    Directory of Open Access Journals (Sweden)

    Fontem, DA.

    1999-01-01

    Full Text Available Tomato (Lycopersicon esculentum production is handicapped by damage due to pests and pathogens. Farmers' fields in the western highlands of Cameroon were surveyed during 1993 to 1996 to identify biological constraints in production. Diseases and insect pests are the most important biological limitations in tomato production. Late blight caused by Phytophthora infestans and early blight caused by Alternaria solani are the most severe diseases, while the melon fruitfly (Dacus cucurbitae is the most prevalent insect pest. Yield losses due to pest damage are high and reach 100 % when the crop is not treated in the wet season. Pest-resistant varieties are not available to farmers. Consequently, growers practise intensive pesticidal spray programmes to limit losses caused by pests and diseases. Results indicate the necessity for the adoption of integrated pest management strategies in tomato production in Cameroon.

  3. Health Impact Assessment and Evaluation of a Clinical Waste Management Policy for Cameroon.

    Science.gov (United States)

    Gulis, Gabriel; Mochungong, Peter Ikome Kuwoh

    2013-06-25

    Health impact assessment (HIA) was carried out to evaluate development of a clinical waste management policy for Cameroon. Fifteen stakeholders of different portfolios within the health sector were selected during a HIA initiating study trip to the Northwest region of Cameroon. Questionnaires were then developed and emailed to the stakeholders. The stakeholders identified cross-contamination, environmental pollution, physical injuries and poor waste management sites as potential risk factors that can be associated with poor clinical waste management. They recommended strong economic and political capital as a prerequisite for the development and implementation of a successful clinical waste policy. Local impacts on health, according to the stakeholders, should be prioritized in deciding any treatment and disposal option. The whole HIA process run through 2008-2010.

  4. Health impact assessment and evaluation of a clinical waste management policy for Cameroon

    Directory of Open Access Journals (Sweden)

    Gabriel Gulis

    2013-09-01

    Full Text Available Health impact assessment (HIA was carried out to evaluate development of a clinical waste management policy for Cameroon. Fifteen stakeholders of different portfolios within the health sector were selected during a HIA initiating study trip to the Northwest region of Cameroon. Questionnaires were then developed and emailed to the stakeholders. The stakeholders identified cross-contamination, environmental pollution, physical injuries and poor waste management sites as potential risk factors that can be associated with poor clinical waste management. They recommended strong economic and political capital as a prerequisite for the development and implementation of a successful clinical waste policy. Local impacts on health, according to the stakeholders, should be prioritized in deciding any treatment and disposal option. The whole HIA process run through 2008-2010.

  5. [Human African trypanosomiasis: description of two pediatric cases in Yaoundé, Cameroon].

    Science.gov (United States)

    Kinkela, M N; Chelo, D; Boula, A; Ebo'O Eyenga, V; Kohagne Tongue, L; Akazong, C A; Kyebyene, A; Tietche, F

    2010-02-01

    During the first decades of the 20th century, about 45% of deaths in Cameroon were believed to be due to human African trypanosomiasis. Thanks to the screening and treatment campaigns implemented between 1926-1932, a considerable regression of the disease was achieved and, by the 1950s, only a few well-known and delimited foci remained. Today, human African trypanosomiasis is an extremely rare diagnosis, especially in children. The purpose of this report is to describe two cases of neuromeningeal human African trypanosomiasis that were discovered coincidentally in two children, ages 12 and 2 years. The children were from two villages in the center of Cameroon that is not considered as a known endemic focus. These two cases raise difficult questions about the possibility of latent endemic foci of human African trypanosomiasis and of animal-to-human transmission. The outcome was favorable in the first case and fatal in the second.

  6. Survey of Minerai Status of Cattle in the Adamaoua Region of Cameroon

    Directory of Open Access Journals (Sweden)

    Njwe, RM.

    1994-01-01

    Full Text Available Serum and liver samples were collected from Zebu Gudali and Zebu Banyo cattle freshly slaughtered in abattoirs at eight different locations in each of the five administrative divisions of the Adamaoua region of Cameroon during the wet season (September to October, 1983 and the dry season (February to March, 1984. Liver samples were analysed for iron, copper and manganese while serum samples were analysed for calcium, magnesium and copper. Most of the animals were adequate in calcium, magnesium, iron and manganese. Copper was deficient in liver and sera of most of the animals. There is a need to intensif/research on the mineral status of cattle in the Adamaoua region of Cameroon. Copper sulphate is recommended in sait licks for cattle in this region.

  7. Phytochemical analysis and biological evaluation of selected African propolis samples from Cameroon and Congo.

    Science.gov (United States)

    Papachroni, Danai; Graikou, Konstantia; Kosalec, Ivan; Damianakos, Harilaos; Ingram, Verina; Chinou, Ioanna

    2015-01-01

    The objective of this study was the chemical analysis of four selected samples of African propolis (Congo and Cameroon) and their biological evaluation. Twenty-one secondary metabolites belonging to four different chemical groups were isolated from the 70% ethanolic extracts of propolis and their structures were elucidated on the basis of spectral evidence. Three triterpenes and two diprenyl-flavonoids were identified from Congo propolis, which has been investigated for the first time, while thirteen triterpenes, three diprenyl-flavonoids, two monoterpenic alcohols and one fatty acid ester have been identified from Cameroon propolis samples. To our knowledge, the identified diprenyl-flavonoids, as well as five of the isolated and determined triterpenes, are reported for the first time in propolis. Moreover, the total polyphenol content was estimated in all extracts and the antimicrobial activities of all four extracts were studied against six Gram-positive and -negative bacteria and three pathogenic fungi, showing an interesting antibacterial profile.

  8. Manyu youths, belonging and the antinomies of patrimonial elite politics in contemporary Cameroon

    DEFF Research Database (Denmark)

    Orock, Rogers Tabe Egbe

    2013-01-01

    actors. It argues that this tension generates relations of mutuality and interdependence between elite and nonelite actors. Yet, the article finds that while the logics of political intimacy between Manyu students and their political elites in Cameroon are mediated by kinship, ethnicity, and patronage......This article explores the social and political connections between youths and political elites from Manyu Division in South-Western Cameroon. Unlike several recent studies on youths in Africa, it focuses on educated youths from Manyu, exploring their strategies to secure greater political inclusion...... and better chances for upward social mobility. With a critical attention to their discourses and practices, the article examines the disjuncture between the promise of Cameroon’s patrimonial state as an inclusive structure of political action and the sense of exclusion, anxiety, and uncertainty felt by many...

  9. Nurses and challenges faced as clinical educators: a survey of a group of nurses in Cameroon

    Directory of Open Access Journals (Sweden)

    Vivian E A Eta

    2011-03-01

    Full Text Available BACKGROUND: Clinical teaching is an important component of clinical education. In nursing, clinical teaching is ensured by clinical nurse educators (CNEs. This study aimed at describing the major challenges faced by CNEs in Cameroon. METHODS: In a qualitative study, supplemented with quantitative methods, CNEs were enrolled from three health districts to represent their frequency in Cameroon’s health delivery system. RESULTS: A total of 56 CNEs participated in the study, of whom, as many as 58.9% acknowledged always facing challenges in clinical teaching and supervision. The major challenges identified were the lack of opportunities to update knowledge and skills, students’ lack of preparedness and the CNEs not being prepared for clinical teaching. CNEs attributed these challenges in major part to the lack of incentives and poor health policies. CONCLUSION: CNEs in Cameroon do indeed face major challenges which are of diverse origins and could adversely affect teaching in clinical settings

  10. Atmospheric chemistry in volcanic plumes.

    Science.gov (United States)

    von Glasow, Roland

    2010-04-13

    Recent field observations have shown that the atmospheric plumes of quiescently degassing volcanoes are chemically very active, pointing to the role of chemical cycles involving halogen species and heterogeneous reactions on aerosol particles that have previously been unexplored for this type of volcanic plumes. Key features of these measurements can be reproduced by numerical models such as the one employed in this study. The model shows sustained high levels of reactive bromine in the plume, leading to extensive ozone destruction, that, depending on plume dispersal, can be maintained for several days. The very high concentrations of sulfur dioxide in the volcanic plume reduces the lifetime of the OH radical drastically, so that it is virtually absent in the volcanic plume. This would imply an increased lifetime of methane in volcanic plumes, unless reactive chlorine chemistry in the plume is strong enough to offset the lack of OH chemistry. A further effect of bromine chemistry in addition to ozone destruction shown by the model studies presented here, is the oxidation of mercury. This relates to mercury that has been coemitted with bromine from the volcano but also to background atmospheric mercury. The rapid oxidation of mercury implies a drastically reduced atmospheric lifetime of mercury so that the contribution of volcanic mercury to the atmospheric background might be less than previously thought. However, the implications, especially health and environmental effects due to deposition, might be substantial and warrant further studies, especially field measurements to test this hypothesis.

  11. Climatic impact of volcanic eruptions

    Science.gov (United States)

    Rampino, Michael R.

    1991-01-01

    Studies have attempted to 'isolate' the volcanic signal in noisy temperature data. This assumes that it is possible to isolate a distinct volcanic signal in a record that may have a combination of forcings (ENSO, solar variability, random fluctuations, volcanism) that all interact. The key to discovering the greatest effects of volcanoes on short-term climate may be to concentrate on temperatures in regions where the effects of aerosol clouds may be amplified by perturbed atmospheric circulation patterns. This is especially true in subpolar and midlatitude areas affected by changes in the position of the polar front. Such climatic perturbation can be detected in proxy evidence such as decrease in tree-ring widths and frost rings, changes in the treeline, weather anomalies, severity of sea-ice in polar and subpolar regions, and poor grain yields and crop failures. In low latitudes, sudden temperature drops were correlated with the passage overhead of the volcanic dust cloud (Stothers, 1984). For some eruptions, such as Tambora, 1815, these kinds of proxy and anectdotal information were summarized in great detail in a number of papers and books (e.g., Post, 1978; Stothers, 1984; Stommel and Stommel, 1986; C. R. Harrington, in press). These studies lead to the general conclusion that regional effects on climate, sometimes quite severe, may be the major impact of large historical volcanic aerosol clouds.

  12. CNA Small Group Discussion: Aiding Cameroon’s Effort to Counter Boko Haram

    Science.gov (United States)

    2015-02-18

    important to understand that the modern (“ colonial ”) borders dividing the Lake Chad Basin region mean little to Boko Haram (and indeed to many...Cameroon is an important partner to the U.S. in Africa , and the two have cooperated on issues including economic development, public health, and...work with its neighbors to counter the threat and prevent its spread within Africa . One participant noted that, like the government of Nigeria, the

  13. Governance of disaster risk reduction in Cameroon: the need to empower local government

    OpenAIRE

    Bang, Henry N.

    2013-01-01

    The impact of natural hazards and/or disasters in Cameroon continues to hit local communities hardest, but local government lacks the ability to manage disaster risks adequately. This is partly due to the fact that the necessity to mainstream disaster risk reduction into local governance and development practices is not yet an underlying principle of Cameroon’s disaster management framework. Using empirical and secondary data, this paper analyses the governance of disaster risk...

  14. The Burden of Leprosy in Cameroon: Fifteen Years into the Post-elimination Era

    Science.gov (United States)

    Tabah, Earnest Njih; Nsagha, Dickson Shey; Bissek, Anne-Cecile Zoung-Kanyi; Bratschi, Martin W.; Njamnshi, Theophilus Ngeh; Plushke, Gerd; Njamnshi, Alfred Kongnyu

    2016-01-01

    Background Cameroon achieved the elimination target of leprosy in 2000, and has maintained this status ever since. However, a number of health districts in the country continue to report significant numbers of leprosy cases. The aim of this study was to assess the burden of leprosy in Cameroon from 2000 to 2014. Methods We obtained and analysed using the new leprosy burden concept of analysis, leprosy surveillance data collected between 2000 and 2014 from the National Leprosy Control Programme. Principal findings Cameroon achieved leprosy elimination in 2000, registering a prevalence rate of 0.94/10,000 population. The prevalence rate dropped further to reach 0.20/10,000 population (78% reduction) in 2014. Similarly, the new case detection rate dropped from 4.88/100,000 population in 2000 to 1.46/100,000 population (85.3% reduction) in 2014. All 10 regions of the country achieved leprosy elimination between 2000 and 2014; however, 10 health districts were still to do so by 2014. The number of high-leprosy-burden regions decreased from 8 in 2000 to 1 in 2014. Seven and two regions were respectively medium and low-burdened at the end of 2014. At the health districts level, 18 remained at the high-leprosy-burdened level in 2014. Conclusion The leprosy prevalence and detection rates as well as the overall leprosy burden in Cameroon have dropped significantly between 2000 and 2014. However, a good number of health districts remain high-leprosy-burdened. The National Leprosy Control Programme should focus efforts on these health districts in the next coming years in order to further reduce the burden of leprosy in the country. PMID:27732603

  15. Fallow practices in West Africa: A comparative importance of phenomenon in Cameroon and Nigeria

    OpenAIRE

    Nkamleu, Guy Blaise

    1999-01-01

    There is a clear need to understand the characteristics of fallow in order to seek appropriate alternatives. From a simultaneous study done in Cameroon and Nigeria, we assessed the specificity of fallow techniques in both countries and discovered that fallow practices remain important in traditional farming systems. Fallow is specifically applied in food crops and forest fields. There are less common in perennial fields and homegardens. Fallow practices remain the major land use technologies ...

  16. Cameroon: UN group finds detention of gay men a violation of human rights.

    Science.gov (United States)

    Pearshouse, Richard; Klein, Alana

    2006-12-01

    In an opinion issued on 11 October 2006, the United Nations Working Group on Arbitrary Detention declared that the detention of 11 men in Cameroon on the basis of their presumed sexual orientation constituted an arbitrary deprivation of liberty and a violation of the principle of equal protection of the law. The Working Group called on the Cameroonian government to "examine the possibility of amending the legislation" criminalizing homosexual sex.

  17. Amodiaquine-Artesunate versus Artemether-Lumefantrine against Uncomplicated Malaria in Children Less Than 14 Years in Ngaoundere, North Cameroon: Efficacy, Safety, and Baseline Drug Resistant Mutations in pfcrt, pfmdr1, and pfdhfr Genes.

    Science.gov (United States)

    Ali, Innocent M; Netongo, Palmer M; Atogho-Tiedeu, Barbara; Ngongang, Eric-Olivier; Ajua, Anthony; Achidi, Eric A; Mbacham, Wilfred F

    2013-01-01

    Background. In Cameroon, both Artesunate-amodiaquine (AS/AQ) and artemether-lumefantrine (AL) are used as first-line treatment against uncomplicated malaria in line with the WHO recommendations. We compared the efficacy and safety of both therapeutic combinations and determined the prevalence of drug resistance conferring mutations in three parasite genes. Methods. One hundred and fifty acute malaria patients between six months and 14 years of age were randomized to receive standard doses of either AS/AQ (73) or AL (77) and followedup for 28 days. Outcome of treatment was according to the standard WHO classification. DNA samples from pretreatment parasite isolates were used to determine the prevalence of resistant mutations in the pfcrt, pfmdr1, and dhfr genes. Results. Both drug combinations induced rapid clearance of parasites and malaria symptoms. PCR-corrected cure rates were 100% and 96.4% for AL. The combinations were well tolerated. Major haplotypes included CVIET (71%), CVMNT (25%) for the pfcrt; SND (100%) for the pfmdr1; IRN (79, 8%), NCS (8.8%), and mixed haplotype (11, 8%) for the dhfr. Conclusion. Both AS/AQ and AL were highly effective and well tolerated for the treatment of uncomplicated falciparum malaria in Ngaoundere, Cameroon. High prevalence of mutant pfcrt alleles confirms earlier observations. Long-term monitoring of safety and efficacy and molecular markers is highly solicited.

  18. Amodiaquine-Artesunate versus Artemether-Lumefantrine against Uncomplicated Malaria in Children Less Than 14 Years in Ngaoundere, North Cameroon: Efficacy, Safety, and Baseline Drug Resistant Mutations in pfcrt, pfmdr1, and pfdhfr Genes

    Directory of Open Access Journals (Sweden)

    Innocent M. Ali

    2013-01-01

    Full Text Available Background. In Cameroon, both Artesunate-amodiaquine (AS/AQ and artemether-lumefantrine (AL are used as first-line treatment against uncomplicated malaria in line with the WHO recommendations. We compared the efficacy and safety of both therapeutic combinations and determined the prevalence of drug resistance conferring mutations in three parasite genes. Methods. One hundred and fifty acute malaria patients between six months and 14 years of age were randomized to receive standard doses of either AS/AQ (73 or AL (77 and followedup for 28 days. Outcome of treatment was according to the standard WHO classification. DNA samples from pretreatment parasite isolates were used to determine the prevalence of resistant mutations in the pfcrt, pfmdr1, and dhfr genes. Results. Both drug combinations induced rapid clearance of parasites and malaria symptoms. PCR-corrected cure rates were 100% and 96.4% for AL. The combinations were well tolerated. Major haplotypes included CVIET (71%, CVMNT (25% for the pfcrt; SND (100% for the pfmdr1; IRN (79, 8%, NCS (8.8%, and mixed haplotype (11, 8% for the dhfr. Conclusion. Both AS/AQ and AL were highly effective and well tolerated for the treatment of uncomplicated falciparum malaria in Ngaoundere, Cameroon. High prevalence of mutant pfcrt alleles confirms earlier observations. Long-term monitoring of safety and efficacy and molecular markers is highly solicited.

  19. Knowledge and practice of condom use as well as perceived barriers among street adolescents in Cameroon

    Directory of Open Access Journals (Sweden)

    Samuel Nambile Cumber

    2016-02-01

    Full Text Available Introduction: Street children in Cameroon are adolescents, vulnerable to sexually transmitted infections (STIs and HIV and/or AIDS. The level of knowledge and practice of condom use among this population is unknown.Objective of the study: To assess the knowledge, practice and barriers to condom use in Cameroon.Materials and methods: The study was an analytical cross-sectional survey conducted in 2015. Questionnaires were administered to street children in a quiet location. Recruitment was made using the snowball technique with the help of peers.Results: More than 90% of participants knew of condoms, but only about 6% reported to have used a condom during their last sexual encounter. Most of the participants did not know that condoms could prevent HIV; only a few (15.5% knew about this.Conclusion: Street adolescents in Cameroon seem to know about condoms, but have insufficient information on the importance of their regular use. The main barriers for the low practice of condom use reported by this population were the following: condoms hinder sexual pleasure; are costly; and it is embarrassing to buy, use or propose to use a condom.

  20. [Vesicular contact dermatitis due to Paederus in Cameroon and review of the literature].

    Science.gov (United States)

    Vanhecke, C; Le Gall, P; Gaüzère, B-A

    2015-12-01

    This irritant blister dermatitis is caused by the genus Paederus whose geographical distribution is worldwide, with a higher incidence in tropical areas. It is induced by direct skin contact with pederin, a blistering and caustic substance found in the abdomen (coelome) of Paederus insects (insect order Coleoptera: family Staphylinidae). The diagnosis is based on the presence of typical clinical features combined with compatible epidemiological features. Our goal is to describe the epidemiological and clinical features of this irritant contact dermatitis in Cameroon through a retrospective study conducted at the end of the rainy season at the Oku Hospital in Northwest Cameroon and to also include cases reported at the medical center of the French Embassy in Yaounde during this same timeframe. In addition, we conducted a literature review of paederus dermatitis. Nineteen patients were included in this study. More than half of the patients presented with more than two lesions predominantly localized to the face or the neck; less than half had complications manifesting as either localized or respiratory reactions and three patients presented periorbital involvement. This study confirms the presence of paederus dermatitis in Cameroon. It is mainly localized in the unusual geoclimatic region of the western high mountains within the country, as well as the usual warm, moist areas of Yaounde. The clinical evolution of this dermatitis is usually one of spontaneous and uneventful resolution with complications being rare. Curative treatment is one of localized topical therapies while oral antibiotic therapy should be reserved for more complicated cases.

  1. Increased Carotid Thickness in Subjects with Recently-Diagnosed Diabetes from Rural Cameroon

    Science.gov (United States)

    Napoli, Nicola; Zardi, Enrico; Strollo, Rocky; Arigliani, Michele; Daverio, Andrea; Olearo, Flaminia; Tosi, Daniele; Dicuonzo, Giordano; Scarpa, Filomena; Pedone, Claudio; Tegue Simo, Hervé Hilaire; Mottini, Giovanni; Pozzilli, Paolo

    2012-01-01

    Background We have recently shown a high prevalence of diabetes and obesity in rural Cameroon, despite an improved lifestyle. Diabetes in rural Africa remains underdiagnosed and its role in increasing risk of atherosclerosis in these populations is unknown. We investigated the prevalence of carotid atherosclerosis and cardiovascular risk factors in a population of subjects with recently-diagnosed diabetes from rural Cameroon. Methodology/Principal Findings In a case-control study, carotid intima-media thickness (IMT) was measured in 74 subjects with diabetes (diagnosed 0.9 mm was found in 4%, 45.9% and 20% of diabetic subjects at the common, bulb or internal carotid, respectively. Only 25% of patients had an HbA1c9%). The prevalence of diabetic subjects with abnormal levels of LDL-cholesterol, triglycerides, HDL-cholesterol or blood pressure was 45%, 16.6%, 15% and 65.7%, respectively. Conclusions Carotid thickness is increased in subjects with diabetes from a rural area of Cameroon, despite the relatively recent diagnosis. These findings and the high rate of uncontrolled diabetes in this population support the increasing concern of diabetes and cardiovascular diseases in African countries and indicate the need for multifaceted health interventions in urban and rural settings. PMID:22916106

  2. Conservation Concern for the Deteriorating Geographical Range of the Grey Parrot in Cameroon

    Directory of Open Access Journals (Sweden)

    Simon A. Tamungang

    2014-01-01

    Full Text Available The need for information on Grey Parrot distribution and vegetation associations for informed management and policy decisions was the basis for this study. A nationwide survey of the Grey Parrot population and habitat status was carried out, using questionnaire and point count methods. From the results, the extent of the contemporary range of the parrots was restricted to Southern Cameroon, which harbours the rainforest. Regional parrot population means ranged from 3,487 parrots in the Littoral to 1,351,275 parrots in the East Regions. The extent of the contemporary range as a percentage of the whole country was 25.4% and as a percentage of the regions with rainforest was 44.5%. The historic range of the bird has been reduced by over 55.5%. Estimated percentage of forest lost per region ranged from 20.4% in the Centre to 57.1% in the East and South Regions. At a global level, Cameroon contributed 9% to the total extent of the range of the Grey Parrot in Africa. The range is increasingly fragmented, contracted, and lost through land-based socioeconomic activities. These degradation pressures on the range called for urgent conservation considerations for long-term survival of the parrot species and its associated biodiversity in Cameroon.

  3. Increased carotid thickness in subjects with recently-diagnosed diabetes from rural Cameroon.

    Directory of Open Access Journals (Sweden)

    Nicola Napoli

    Full Text Available BACKGROUND: We have recently shown a high prevalence of diabetes and obesity in rural Cameroon, despite an improved lifestyle. Diabetes in rural Africa remains underdiagnosed and its role in increasing risk of atherosclerosis in these populations is unknown. We investigated the prevalence of carotid atherosclerosis and cardiovascular risk factors in a population of subjects with recently-diagnosed diabetes from rural Cameroon. METHODOLOGY/PRINCIPAL FINDINGS: In a case-control study, carotid intima-media thickness (IMT was measured in 74 subjects with diabetes (diagnosed 0.9 mm was found in 4%, 45.9% and 20% of diabetic subjects at the common, bulb or internal carotid, respectively. Only 25% of patients had an HbA1c9%. The prevalence of diabetic subjects with abnormal levels of LDL-cholesterol, triglycerides, HDL-cholesterol or blood pressure was 45%, 16.6%, 15% and 65.7%, respectively. CONCLUSIONS: Carotid thickness is increased in subjects with diabetes from a rural area of Cameroon, despite the relatively recent diagnosis. These findings and the high rate of uncontrolled diabetes in this population support the increasing concern of diabetes and cardiovascular diseases in African countries and indicate the need for multifaceted health interventions in urban and rural settings.

  4. Nutritional composition, bioactive compounds and volatile profile of cocoa beans from different regions of Cameroon.

    Science.gov (United States)

    Caprioli, Giovanni; Fiorini, Dennis; Maggi, Filippo; Nicoletti, Marcello; Ricciutelli, Massimo; Toniolo, Chiara; Prosper, Biapa; Vittori, Sauro; Sagratini, Gianni

    2016-06-01

    Analysis of the complex composition of cocoa beans provides fundamental information for evaluating the quality and nutritional aspects of cocoa-based food products, nutraceuticals and supplements. Cameroon, the world's fourth largest producer of cocoa, has been defined as "Africa in miniature" because of the variety it habitats. In order to evaluate the nutritional characteristics of cocoa beans from five different regions of Cameroon, we studied their polyphenolic content, volatile compounds and fatty acids composition. The High Performance Thin Layer Chromatography (HPTLC) analysis showed that the Mbalmayo sample had the highest content of theobromine (11.6 mg/g) and caffeic acid (2.1 mg/g), while the Sanchou sample had the highest level of (-)-epicatechin (142.9 mg/g). Concerning fatty acids, the lowest level of stearic acid was found in the Mbalmayo sample while the Bertoua sample showed the highest content of oleic acid. Thus, we confirmed that geographical origin influences the quality and nutritional characteristics of cocoa from these regions of Cameroon.

  5. Governance of disaster risk reduction in Cameroon: The need to empower local government

    Directory of Open Access Journals (Sweden)

    Henry N. Bang

    2013-01-01

    Full Text Available The impact of natural hazards and/or disasters in Cameroon continues to hit local communities hardest, but local government lacks the ability to manage disaster risks adequately. This is partly due to the fact that the necessity to mainstream disaster risk reduction into local governance and development practices is not yet an underlying principle of Cameroon’s disaster management framework. Using empirical and secondary data, this paper analyses the governance of disaster risks in Cameroon with particular focus on the challenges local government faces in implementing disaster risk reduction strategies. The hypothesis is that the governance of disaster risks is too centralised at the national level, with huge implications for the effective governance of disaster risks at the local level. Although Cameroon has reinvigorated efforts to address growing disaster risks in a proactive way, it is argued that the practical actions are more reactive than proactive in nature. The overall aim is to explore the challenges and opportunities that local government has in the governance of disaster risks. Based on the findings from this research, policy recommendations are suggested on ways to mainstream disaster risk reduction strategies into local governance, and advance understanding and practice in the local governance of disaster risks in the country.

  6. The Amphibians of Mount Oku, Cameroon: an updated species inventory and conservation review

    Science.gov (United States)

    Doherty-Bone, Thomas M.; Gvoždík, Václav

    2017-01-01

    Abstract Amphibians are a disproportionately threatened group of vertebrates, the status of which in Sub-Saharan Africa is still uncertain, with heterogeneous fauna punctuated by mountains. Mount Oku, Cameroon is one such mountain, which holds many endemic and restricted-range species. The history of amphibian research on Mt Oku, current knowledge on biogeography and conservation biology is reviewed, including recent findings. This updated inventory adds 25 further species, with 50 species of amphibian so far recorded to the Oku Massif (c. 900 to 3,011 m). This includes 5 endemic to Mt Oku, 7 endemic to the Bamenda Highlands, 18 restricted to the highlands of Cameroon and Nigeria, and 20 with broader ranges across Africa. This includes a new mountain locality for the Critically Endangered Leptodactylodon axillaris. Among others, the first record of Phrynobatrachus schioetzi and Ptychadena taenioscelis from Cameroon are presented. The uncertainty of habitat affinities and elevational ranges are discussed. The proportion of threatened species on Mt Oku is 44.2%, but projected to increase to 47.9% due to new species descriptions and recent dramatic declines. The natural habitats of Mt Oku are irreplaceable refuges for its endemic and restricted-range amphibian populations under severe pressure elsewhere in their range. Threats to this important amphibian fauna are increasing, including agricultural encroachment, expanding aquaculture, livestock grazing, pollution, invasive species, forest loss and degradation. Past, present and desired conservation interventions to address these threats are discussed. PMID:28144180

  7. Unilateral childhood blindness: a hospital-based study in Yaoundé, Cameroon

    Directory of Open Access Journals (Sweden)

    André; Omgbwa Eballe

    2009-08-01

    Full Text Available André Omgbwa Eballe1, Emilienne Epée2, Godefroy Koki2, Lucienne Bella2, Côme Ebana Mvogo21Faculty of Medicine and Pharmaceutical Sciences, University of Douala, Douala, Cameroon; 2Faculty of Medicine and Biomedical Sciences, University of Yaoundé I, Yaoundé, CameroonIntroduction: We performed an analytic and prospective study over a period of 12 months from January 2nd to December 31st, 2008, at the Gynaeco-Obstetric and Paediatric Hospital of Yaoundé, Cameroon. Our aim was to determine the prevalence and causes of unilateral blindness in school children aged 6 to 15 years.Results: Among the 1,266 children aged 6 to 15 years who were recruited, 60 presented with unilateral blindness (4.7%: 42 boys (6.96% and 18 girls (2.71%. The mean age was 10.15 ± 3.4 years. In patients with unilateral blindness, 65% was due to ocular trauma.Discussion: The hospital-based prevalence of unilateral blindness in children is relatively high and ocular trauma is the leading etiology.Conclusion: Unilateral blindness in school children is avoidable and its incidence could be markedly reduced by emphasizing an information strategy and education based on prevention of ocular trauma. Early management of nontraumatic diseases such as infantile glaucoma and some tumors could improve outcome and avoid blindness.Keywords: unilateral blindness, ocular trauma, prevalence, education

  8. Oil depletion and development in Cameroon: A critical appraisal of the permanent income hypothesis

    Energy Technology Data Exchange (ETDEWEB)

    Djiofack, Calvin Z., E-mail: cdjiofack@worldbank.org [World Bank, Latin America and Caribbean, 1818 H Street, NW Washington, DC 20433 (United States); Omgba, Luc Desire, E-mail: Desire.OMGBA@supco-amiens.fr [Amiens School of Management, 18, Place Saint Michel-80038 Amiens Cedex 1 (France)

    2011-11-15

    This paper focuses on medium term policy options in the economic context of natural resource depletion. In particular, a novel approach for analyzing the impact of the permanent income hypothesis (PIH) with a dynamic recursive computable general equilibrium (CGE) model is employed. The model is benchmarked in an oil producing country with declining production, namely Cameroon. The results show that the PIH renders public finances less vulnerable during the post-oil transition. However, adopting the PIH is not associated with substantial improvements in growth and household welfare in Cameroon. Therefore, the PIH cannot be the only basis for better management of oil revenues in the country. - Highlights: > We assess for the first time, the adoption of permanent income hypothesis (PIH) in a dynamic CGE model. > The model is benchmarked in an oil country with declining production, namely Cameroon. > PIH renders public finances less vulnerable during the post-oil transition. > However, adopting the PIH is not associated with significant improvement of the growth and households' welfare.

  9. Distribution and heterogeneity of hepatitis C genotypes in hepatitis patients in Cameroon.

    Science.gov (United States)

    Pasquier, Christophe; Njouom, Richard; Ayouba, Ahidjo; Dubois, Martine; Sartre, Michèle Tagni; Vessière, Aurelia; Timba, Isabelle; Thonnon, Jocelyn; Izopet, Jacques; Nerrienet, Eric

    2005-11-01

    Hepatitis C virus infects humans world-wide. The virus genome varies greatly and it has several genotypes. HCV infection is highly prevalent in Central Africa and Cameroon. Initial studies on the genetic variability of HCV showed infection with HCV genotypes 1, 2, and 4. We have now sequenced the NS5b and E2 regions of 156 HCV isolates collected from patients presenting for diagnosis in Yaounde and used the data to describe the distribution of HCV genotypes and subtypes in patients with hepatitis in Cameroon. Genotype 1 was more frequent than Genotypes 4 and 2. Genotypes 1 and 4 were highly heterogeneous, containing many subtypes described previously (1b, 1c, 1e, 1h, 1l, 4f, 4t, 4p, 4k) and unsubtyped groups. There was a systematic phylogenetic concordance between NS5b and E2 sequence clustering. The Genotype 2 sequences did not vary. Neither subject age nor gender influenced HCV distribution. HCV Genotypes 1 and 4 are very heterogeneous in Cameroon, perhaps due to ancient infections. The homogeneity of HCV Genotype 2 indicates its more recent introduction from western Africa.

  10. Treatment of malaria from monotherapy to artemisinin-based combination therapy by health professionals in rural health facilities in southern Cameroon

    Directory of Open Access Journals (Sweden)

    Bley Daniel

    2009-07-01

    Full Text Available Abstract Background One year after the adoption of artesunate-amodiaquine (AS/AQ as first-line therapy for the treatment of uncomplicated malaria, this study was designed to assess the treatment practices regarding anti-malarial drugs at health facilities in four rural areas in southern Cameroon. Methods Between April and August 2005, information was collected by interviewing fifty-two health professionals from twelve rural health facilities, using a structured questionnaire. Results In 2005, only three anti-malarial drugs were used in rural health facilities, including: amodiaquine, quinine and sulphadoxine-pyrimethamine. Only 2.0% of the health professionals prescribed the recommended AS/AQ combination. After reading the treatment guidelines, 75.0% were in favour of the treatment protocol with the following limitations: lack of paediatric formulations, high cost and large number of tablets per day. Up to 21.0% of professionals did not prescribe AS/AQ because of the level of adverse events attributed to the use of amodiaquine as monotherapy. Conclusion The present study indicates that AS/AQ was not available in the public health facilities at the time of the study, and health practitioners were not informed about the new treatment guidelines. Results of qualitative analysis suggest that prescribers should be involved as soon as possible in projects related to the optimization of treatment guidelines and comply with new drugs. Adapted formulations should be made available at the international level and implemented locally before new drugs and treatments are proposed through a national control programme. This baseline information will be useful to monitor progresses in the implementation of artemisinin-based combination therapy in Cameroon.

  11. Geopulsation, Volcanism and Astronomical Periods

    Institute of Scientific and Technical Information of China (English)

    Yang Xuexiang; Chen Dianyou; Yang Xiaoying; Yang Shuchen

    2000-01-01

    Volcanism is mainly controlled by the intermittent release of energy in the earth. As far as the differential rotation of the earth's inner core is concerned, the Galactic Year may change the gravitational constant G, the solar radiative quantity and the moving speed of the solar system and affect the exchange of angular momentum between core and mantle as well as the energy exchange between crust and mantle. As a result, this leads to eruptions of superplumes and magma, and controls the energy flow from core - mantle boundary (CMB) to crust. When the earth' s speed decreases, it will release a huge amount of energy. They are the reason of the correspondence of the volcanic cycles one by one with the astronomical periods one by one. According to the astronomical periods, volcanic eruptions may possibly be predicted in the future.

  12. Geochemical study for volcanic surveillance

    Energy Technology Data Exchange (ETDEWEB)

    Panichi, C.; La Ruffa, G. [Consiglio Nazionale delle Ricerche, International Institute for Geothermal Research Ghezzano, PI (Italy)

    2000-07-01

    For years, geologists have been striving to reconstruct volcanic eruptions from the analysis of pyroclastic deposits and lava flows on the surface of the earth and in the oceans. This effort has produced valuable information on volcanic petrology and magma generation, separation, mixing, crystallisation, and interaction with water in phreatomagmatic and submarine eruptions. The volcanological process are tied to the dynamics of the earth's crust and lithosphere. The mantle, subducted oceanic crust, and continental crust contain different rock types and are sources of different magmas. Magmas consist primarily of completely or partially molten silicates containing volatile materials either dissolved in the melt or as bubbles of gas. The silicate and volatile portions affect the physical properties of magma and, therefore, the nature of a volcanic eruption.

  13. Models of volcanic eruption hazards

    Energy Technology Data Exchange (ETDEWEB)

    Wohletz, K.H.

    1992-01-01

    Volcanic eruptions pose an ever present but poorly constrained hazard to life and property for geothermal installations in volcanic areas. Because eruptions occur sporadically and may limit field access, quantitative and systematic field studies of eruptions are difficult to complete. Circumventing this difficulty, laboratory models and numerical simulations are pivotal in building our understanding of eruptions. For example, the results of fuel-coolant interaction experiments show that magma-water interaction controls many eruption styles. Applying these results, increasing numbers of field studies now document and interpret the role of external water eruptions. Similarly, numerical simulations solve the fundamental physics of high-speed fluid flow and give quantitative predictions that elucidate the complexities of pyroclastic flows and surges. A primary goal of these models is to guide geologists in searching for critical field relationships and making their interpretations. Coupled with field work, modeling is beginning to allow more quantitative and predictive volcanic hazard assessments.

  14. Recurrence models of volcanic events: Applications to volcanic risk assessment

    Energy Technology Data Exchange (ETDEWEB)

    Crowe, B.M. [Los Alamos National Lab., Las Vegas, NV (United States); Picard, R.; Valentine, G. [Los Alamos National Lab., NM (United States); Perry, F.V. [New Mexico Univ., Albuquerque, NM (United States)

    1992-03-01

    An assessment of the risk of future volcanism has been conducted for isolation of high-level radioactive waste at the potential Yucca Mountain site in southern Nevada. Risk used in this context refers to a combined assessment of the probability and consequences of future volcanic activity. Past studies established bounds on the probability of magmatic disruption of a repository. These bounds were revised as additional data were gathered from site characterization studies. The probability of direct intersection of a potential repository located in an eight km{sup 2} area of Yucca Mountain by ascending basalt magma was bounded by the range of 10{sup {minus}8} to 10{sup {minus}10} yr{sup {minus}1 2}. The consequences of magmatic disruption of a repository were estimated in previous studies to be limited. The exact releases from such an event are dependent on the strike of an intruding basalt dike relative to the repository geometry, the timing of the basaltic event relative to the age of the radioactive waste and the mechanisms of release and dispersal of the waste radionuclides in the accessible environment. The combined low probability of repository disruption and the limited releases associated with this event established the basis for the judgement that the risk of future volcanism was relatively low. It was reasoned that that risk of future volcanism was not likely to result in disqualification of the potential Yucca Mountain site.

  15. Controls on volcanism at intraplate basaltic volcanic fields

    Science.gov (United States)

    van den Hove, Jackson C.; Van Otterloo, Jozua; Betts, Peter G.; Ailleres, Laurent; Cas, Ray A. F.

    2017-02-01

    A broad range of controlling mechanisms is described for intraplate basaltic volcanic fields (IBVFs) in the literature. These correspond with those relating to shallow tectonic processes and to deep mantle plumes. Accurate measurement of the physical parameters of intraplate volcanism is fundamental to gain an understanding of the controlling factors that influence the scale and location of a specific IBVF. Detailed volume and geochronology data are required for this; however, these are not available for many IBVFs. In this study the primary controls on magma genesis and transportation are established for the Pliocene-Recent Newer Volcanics Province (NVP) of south-eastern Australia as a case-study for one of such IBVF. The NVP is a large and spatio-temporally complex IBVF that has been described as either being related to a deep mantle plume, or upper mantle and crustal processes. We use innovative high resolution aeromagnetic and 3D modelling analysis, constrained by well-log data, to calculate its dimensions, volume and long-term eruptive flux. Our estimates suggest volcanic deposits cover an area of 23,100 ± 530 km2 and have a preserved dense rock equivalent of erupted volcanics of least 680 km3, and may have been as large as 900 km3. The long-term mean eruptive flux of the NVP is estimated between 0.15 and 0.20 km3/ka, which is relatively high compared with other IBVFs. Our comparison with other IBVFs shows eruptive fluxes vary up to two orders of magnitude within individual fields. Most examples where a range of eruptive flux is available for an IBVF show a correlation between eruptive flux and the rate of local tectonic processes, suggesting tectonic control. Limited age dating of the NVP has been used to suggest there were pulses in its eruptive flux, which are not resolvable using current data. These changes in eruptive flux are not directly relatable to the rate of any interpreted tectonic driver such as edge-driven convection. However, the NVP and other

  16. Feasibility of pico-hydro and photovoltaic hybrid power systems for remote villages in Cameroon

    Energy Technology Data Exchange (ETDEWEB)

    Nfah, E.M. [Laboratoire d' Automatique et d' Informatique Appliquee, I.U.T. Fotso Victor, P.O. Box 134, Bandjoun, University of Dschang (Cameroon); Ngundam, J.M. [Automation and Control Laboratory, School of Engineering, P.O. Box 8390, University of Yaounde I (Cameroon)

    2009-06-15

    Pico-hydro (pH) and photovoltaic (PV) hybrid systems incorporating a biogas generator have been simulated for remote villages in Cameroon using a load of 73 kWh/day and 8.3 kWp. Renewable energy systems were simulated using HOMER, the load profile of a hostel in Cameroon, the solar insolation of Garoua and the flow of river Mungo. For a 40% increase in the cost of imported power system components, the cost of energy was found to be either 0.352 EUR/kWh for a 5 kW pico-hydro generator with 72 kWh storage or 0.396 EUR/kWh for a 3 kWp photovoltaic generator with 36 kWh storage. These energy costs were obtained with a biomass resource cost of 25 EUR/tonne. The pH and PV hybrid systems both required the parallel operation of a 3.3 kW battery inverter with a 10 kW biogas generator. The pH/biogas/battery systems simulated for villages located in the south of Cameroon with a flow rate of at least 92 l/s produced lower energy costs than PV/biogas/battery systems simulated for villages in the north of Cameroon with an insolation level of at least 5.55 kWh/m{sup 2}/day. For a single-wire grid extension cost of 5000 EUR/km, operation and maintenance costs of 125 EUR/yr/km and a grid power price of 0.1 EUR/kWh, the breakeven grid extension distances were found to be 12.9 km for pH/biogas/battery systems and 15.2 km for PV/biogas/battery systems respectively. Investments in biogas based renewable energy systems could thus be considered in the National Energy Action Plan of Cameroon for the supply of energy to key sectors involved in poverty alleviation. (author)

  17. A quantitative model for volcanic hazard assessment

    OpenAIRE

    W. Marzocchi; Sandri, L.; Furlan, C

    2006-01-01

    Volcanic hazard assessment is a basic ingredient for risk-based decision-making in land-use planning and emergency management. Volcanic hazard is defined as the probability of any particular area being affected by a destructive volcanic event within a given period of time (Fournier d’Albe 1979). The probabilistic nature of such an important issue derives from the fact that volcanic activity is a complex process, characterized by several and usually unknown degrees o...

  18. Volcanic forcing in decadal forecasts

    Science.gov (United States)

    Ménégoz, Martin; Doblas-Reyes, Francisco; Guemas, Virginie; Asif, Muhammad; Prodhomme, chloe

    2016-04-01

    Volcanic eruptions can significantly impact the climate system, by injecting large amounts of particles into the stratosphere. By reflecting backward the solar radiation, these particles cool the troposphere, and by absorbing the longwave radiation, they warm the stratosphere. As a consequence of this radiative forcing, the global mean surface temperature can decrease by several tenths of degrees. However, large eruptions are also associated to a complex dynamical response of the climate system that is particularly tricky do understand regarding the low number of available observations. Observations seem to show an increase of the positive phases of the Northern Atlantic Oscillation (NAO) the two winters following large eruptions, associated to positive temperature anomalies over the Eurasian continent. The summers following large eruptions are generally particularly cold, especially over the continents of the Northern Hemisphere. Overall, it is really challenging to forecast the climate response to large eruptions, as it is both modulated by, and superimposed to the climate background conditions, largely driven themselves by internal variability at seasonal to decadal scales. This work describes the additional skill of a forecast system used for seasonal and decadal predictions when it includes observed volcanic forcing over the last decades. An idealized volcanic forcing that could be used for real-time forecasts is also evaluated. This work consists in a base for forecasts that will be performed in the context of the next large volcanic eruption.

  19. Experimental generation of volcanic lightning

    Science.gov (United States)

    Cimarelli, Corrado; Alatorre-Ibargüengoitia, Miguel; Kueppers, Ulrich; Scheu, Bettina; Dingwell, Donald B.

    2014-05-01

    Ash-rich volcanic plumes that are responsible for injecting large quantities of aerosols into the atmosphere are often associated with intense electrical activity. Direct measurement of the electric potential at the crater, where the electric activity in the volcanic plume is first observed, is severely impeded, limiting progress in its investigation. We have achieved volcanic lightning in the laboratory during rapid decompression experiments of gas-particle mixtures under controlled conditions. Upon decompression (from ~100 bar argon pressure to atmospheric pressure), loose particles are vertically accelerated and ejected through a nozzle of 2.8 cm diameter into a large tank filled with air at atmospheric conditions. Because of their impulsive character, our experiments most closely represent the conditions encountered in the gas-thrust region of the plume, when ash is first ejected from the crater. We used sieved natural ash with different grain sizes from Popocatépetl (Mexico), Eyjafjallajökull (Iceland), and Soufrière Hills (Montserrat) volcanoes, as well as micrometric glass beads to constrain the influence of material properties on lightning. We monitored the dynamics of the particle-laden jets with a high-speed camera and the pressure and electric potential at the nozzle using a pressure transducer and two copper ring antennas connected to a high-impedance data acquisition system, respectively. We find that lightning is controlled by the dynamics of the particle-laden jet and by the abundance of fine particles. Two main conditions are required to generate lightning: 1) self-electrification of the particles and 2) clustering of the particles driven by the jet fluid dynamics. The relative movement of clusters of charged particles within the plume generates the gradient in electrical potential, which is necessary for lightning. In this manner it is the gas-particle dynamics together with the evolving particle-density distribution within different regions of

  20. A Volcanic Hydrogen Habitable Zone

    Science.gov (United States)

    Ramirez, Ramses M.; Kaltenegger, Lisa

    2017-03-01

    The classical habitable zone (HZ) is the circular region around a star in which liquid water could exist on the surface of a rocky planet. The outer edge of the traditional N2–CO2–H2O HZ extends out to nearly ∼1.7 au in our solar system, beyond which condensation and scattering by CO2 outstrips its greenhouse capacity. Here, we show that volcanic outgassing of atmospheric H2 can extend the outer edge of the HZ to ∼2.4 au in our solar system. This wider volcanic-hydrogen HZ (N2–CO2–H2O–H2) can be sustained as long as volcanic H2 output offsets its escape from the top of the atmosphere. We use a single-column radiative-convective climate model to compute the HZ limits of this volcanic hydrogen HZ for hydrogen concentrations between 1% and 50%, assuming diffusion-limited atmospheric escape. At a hydrogen concentration of 50%, the effective stellar flux required to support the outer edge decreases by ∼35%–60% for M–A stars. The corresponding orbital distances increase by ∼30%–60%. The inner edge of this HZ only moves out ∼0.1%–4% relative to the classical HZ because H2 warming is reduced in dense H2O atmospheres. The atmospheric scale heights of such volcanic H2 atmospheres near the outer edge of the HZ also increase, facilitating remote detection of atmospheric signatures.

  1. Addressing the concerns of rural communities about access to plants and knowledge in a sui generis legislation in Cameroon

    Indian Academy of Sciences (India)

    Marcelin Tonye Mahop

    2004-12-01

    This article assesses the traditional systems of accessing and using plant genetic resources as well as the benefit sharing and systems of sanctioning infringement in the context of biodiversity related activities in specific areas in the Northwest province of Cameroon. The article also addresses the type research and development activities using plant genetic resources and associated traditional knowledge in the context of Cameroon, the current laws regulating such activities and the extent to which these activities and laws affect and/or protect the customary biodiversity rights of rural communities. The article uses these assessments to suggest the context under which a sui generis legislation for the protection of the biodiversity rights of rural communities can be established in Cameroon.

  2. How Volcanism Controls Climate Change

    Science.gov (United States)

    Ward, P. L.

    2013-12-01

    Large explosive volcanoes eject megatons of sulfur dioxide into the lower stratosphere where it spreads around the world within months and is oxidized slowly to form a sulfuric-acid aerosol with particle sizes that grow large enough to reflect and scatter solar radiation, cooling Earth ~0.5C for up to 3 years. Explosive eruptions also deplete total column ozone ~6% causing up to 3C winter warming at mid-latitudes over continents. Global cooling predominates. Extrusive, basaltic volcanoes deplete ozone ~6% but do not eject much sulfur dioxide into the lower stratosphere, causing net global warming. Anthropogenic chlorofluorocarbons (CFCs) deplete ozone ~3% for up to a century while each volcanic eruption, even small ones, depletes ozone twice as much but for less than a decade through eruption of halogens and ensuing photochemical processes. The 2010 eruption of Eyjafjallajökull, the 2011 eruption of Grímsvötn, plus anthropogenic CFCs depleted ozone over Toronto Canada 14% in 2012, causing an unusually warm winter and drought. Total column ozone determines how much solar ultraviolet energy with wavelengths between 290 and 340 nanometers reaches Earth where it is absorbed most efficiently by the ocean. A 25% depletion of ozone increases the amount of this radiation reaching Earth by 1 W m-2 for overhead sun and 0.25 W m-2 for a solar zenith angle of 70 degrees. The tropopause is the boundary between the troposphere heated from below by a sun-warmed Earth and the stratosphere heated from above by the Sun through photodissociation primarily of oxygen and ozone. The mean annual height of the tropopause increased ~160 m between 1980 and 2004 at the same time that northern mid-latitude total column ozone was depleted by ~4%, the lower stratosphere cooled ~2C, the upper troposphere warmed ~0.1C, and mean surface temperatures in the northern hemisphere rose ~0.5C. Regional total ozone columns are observed to increase as rapidly as 20% within 5 hours with an associated 5

  3. DIVERSITY, STRUCTURAL PARAMETERS AND NON-TIMBER FOREST PRODUCTS IN THE FOREST RESERVE OF BONEPOUPA (DOUALA, CAMEROON

    Directory of Open Access Journals (Sweden)

    Jean Paul Kamdem

    2013-12-01

    Full Text Available http://dx.doi.org/10.5902/1980509812363In order to come up with a sustainable use of forest ecosystems in Cameroon, its vegetal diversity has been inventoried; the plant potentials and the structural parameters were studied in the forest reserve of Bonepoupa. Ten non-continuous plots of 200 m² were done and the materialization of the lines was done with a topofil put at the centre of the field with ropes at 5 m each of the topofil. In addition, ninety people were interviewed in order to know the potential use of species in this region. Up to 172 individuals with Diameter at Breast Height (DBH ≥ 5 cm divided into 27 species, 25 genera and 18 families were inventoried and the coefficient of abundance-dominance was determined. The diversity index of Shannon (H’ was H’1 = 4.17 ± 0.45 with H’1max = 4.75 and the evenness was R1 = 0.88. Taking into account herbaceous species, H’ determined by the coefficient of abundance-dominance was H’2 = 4.74 ± 0.56 with H’2max = 5.70 and the evenness  was  R2 = 0.83. The  total  basal  area  was 19.69 m2/ha and the density was 860 individuals/ha. These results indicate that herbaceous significantly modifies the value of the diversity index and that forest reserve of Bonepoupa is experiencing a problem of conservation which is due to a lack of its appropriate management. The knowledge of non-timber forest products and their use as food as well as medicinal resources by local population might be helpful for the sustainable management of resources in this forest reserve.

  4. Hospital Workers' Awareness of Health and Environmental Impacts of Poor Clinical Waste Disposal in the Northwest Region of Cameroon

    DEFF Research Database (Denmark)

    Mochungong, Peter I. K.; Gulis, Gabriel; Sodemann, Morten

    2010-01-01

    a survey to evaluate hospital workers' awareness of health and environmental impacts of poor clinical waste disposal in Cameroon. We randomly distributed 500 questionnaires to hospital workers in three hospitals in the Northwest Region of Cameroon in April 2008. In addition, we observed collection......, segregation, transportation, and disposal of clinical waste at the three hospitals. Of 475 total respondents, most lacked sufficient awareness of any environmental or public health impacts of poor clinical waste disposal and had never heard of any policy-national or international- on safe clinical waste...

  5. Treatment of malaria from monotherapy to artemisinin-based combination therapy by health professionals in urban health facilities in Yaoundé, central province, Cameroon

    Directory of Open Access Journals (Sweden)

    Bley Daniel

    2009-07-01

    Full Text Available Abstract Background After adoption of artesunate-amodiaquine (AS/AQ as first-line therapy for the treatment of uncomplicated malaria by the malaria control programme, this study was designed to assess the availability of anti-malarial drugs, treatment practices and acceptability of the new protocol by health professionals, in the urban health facilities and drugstores of Yaoundé city, Cameroon. Methods Between April and August 2005, retrospective and current information was collected by consulting registers and interviewing health practitioners in urban health facilities using a structured questionnaire. Results In 2005, twenty-seven trade-named drugs have been identified in drugstores; quinine tablets (300 mg were the most affordable anti-malarial drugs. Chloroquine was restricted to food market places and no generic artemisinin derivative was available in public health centres. In public health facilities, 13.6% of health professionals were informed about the new guidelines; 73.5% supported the use of AS-AQ as first-line therapy. However, 38.6% apprehended its use due to adverse events attributed to amodiaquine. Malaria treatment was mainly based on the diagnosis of fever. Quinine (300 mg tablets was the most commonly prescribed first-line anti-malarial drug in adults (44.5% and pregnant women (52.5%. Artequin® was the most cited artemsinin-based combination therapy (ACT (9.9%. Medical sales representatives were the main sources of information on anti-malarials. Conclusion The use of AS/AQ was not implemented in 2005 in Yaoundé, despite the wide range of anti-malarials and trade-named artemisinin derivatives available. Nevertheless, medical practitioners will support the use of this combination, when it is available in a paediatric formulation, at an affordable price. Training, information and participation of health professionals in decision-making is one of the key elements to improve adherence to new protocol guidelines. This baseline

  6. Multidimensional analysis and probabilistic model of volcanic and seismic activities

    Science.gov (United States)

    Fedorov, V.

    2009-04-01

    body, as well as to forecast of changes in its relief. As the volcanic and seismic processes are of cosmic nature and occurrence, it seems logical to investigate their chronological structure in terms of astronomical time reference system or in parameters of the Earth orbital movement. Gravitational interaction of the Earth with the moon, the Sun and planets of the Solar system forms the physical basis of this multidimensional system; it manifests itself in tidal deformations of the Earth's lithosphere and in periodical changes in the planet rotation and orbital speed. A search for chronological correlation between the Earth's volcanism and seismicity on one hand and the orbital parameters dynamic on the other shows a certain promise in relation to prognostic decisions. It should be kept in mind that the calculation of astronomical characteristics (Ephemerides), which is one of the main lines in theoretical astronomy, spans many years both in the past and in future. It seems appropriate therefore to apply the astronomical time reference system to investigations of chronological structure of volcanic and seismic processes from the methodical viewpoint, as well as for retrospective and prognostic analyses. To investigate temporal pattern of the volcanic and seismic processes and to find a degree of their dependence on tidal forces, we used the astronomical time reference system as related to the Earth's orbital movement. The system is based on substitution of calendar dates of eruption and earthquakes for corresponding values of known astronomical characteristics, such as the Earth to Sun and Earth to Moon distances, ecliptic latitude of the Moon, etc. In coordinates of astronomical parameters (JPL Planetary and Lunar Efemerides, 1997, as compiled by the Jet Propulsion Laboratory, California Institute of Technology, on the basis of DE 406 block developed by NASA), we analyzed massifs of information, both volcanological (Catalogue of the World volcanic eruptions by I

  7. Anomalous diffusion of volcanic earthquakes

    CERN Document Server

    Abe, Sumiyoshi

    2015-01-01

    Volcanic seismicity at Mt. Etna is studied. It is found that the associated stochastic process exhibits a subdiffusive phenomenon. The jump probability distribution well obeys an exponential law, whereas the waiting-time distribution follows a power law in a wide range. Although these results would seem to suggest that the phenomenon could be described by temporally-fractional kinetic theory based on the viewpoint of continuous-time random walks, the exponent of the power-law waiting-time distribution actually lies outside of the range allowed in the theory. In addition, there exists the aging phenomenon in the event-time averaged mean squared displacement, in contrast to the picture of fractional Brownian motion. Comments are also made on possible relevances of random walks on fractals as well as nonlinear kinetics. Thus, problems of volcanic seismicity are highly challenging for science of complex systems.

  8. Source mechanisms of volcanic tsunamis.

    Science.gov (United States)

    Paris, Raphaël

    2015-10-28

    Volcanic tsunamis are generated by a variety of mechanisms, including volcano-tectonic earthquakes, slope instabilities, pyroclastic flows, underwater explosions, shock waves and caldera collapse. In this review, we focus on the lessons that can be learnt from past events and address the influence of parameters such as volume flux of mass flows, explosion energy or duration of caldera collapse on tsunami generation. The diversity of waves in terms of amplitude, period, form, dispersion, etc. poses difficulties for integration and harmonization of sources to be used for numerical models and probabilistic tsunami hazard maps. In many cases, monitoring and warning of volcanic tsunamis remain challenging (further technical and scientific developments being necessary) and must be coupled with policies of population preparedness.

  9. Hormonal contraception, sexual behaviour and HIV prevalence among women in Cameroon

    Directory of Open Access Journals (Sweden)

    Soskolne Varda

    2008-10-01

    Full Text Available Abstract Background Data on the effect of contraceptive methods, other than the condom, on HIV acquisition is not clear. The aim of this study was to describe hormonal contraceptive use, sexual behaviour and HIV prevalence among women in Cameroon in order to provide baseline information for future analytical studies. Methods This is a cross-sectional descriptive study based a nationally representative sample of 4486 sexually active women aged 15–49 years who participated in the 2004 Cameroon Demographic and Health Survey. Results The overall HIV prevalence was 7.4% (332/4486. The HIV prevalence was higher in the 25–35 year age group (10.03%, urban residents (9.39%, and formerly married (18.48%, compared to their compatriots. The prevalence was lower in women with five or more living child (3.67%, women in the low wealth index category (3.79% and women who had no formal education (3.37%. The HIV prevalence was higher among women who had two or more partners in the last 12 months (10.26% and women who reported to have had four or more partners in their lifetime (12.40%. The prevalence of HIV was higher among current hormonal contraceptive users (6.63% compared to the current non-users (3.06%, among ever users of hormonal contraception (13.27% compared to the never users (7.11%. Conclusion We conclude that the prevalence of HIV among sexually active women in Cameroon varies according to sociodemographic characteristics, sexual behaviour and hormonal contraceptive use. Our findings underscore the need to counsel women using hormonal contraception to be aware that hormonal methods do not protect against HIV infection. Given the biologic plausibility of the link between hormonal contraception and HIV infection, future research should focus on carefully designed prospective studies to establish the temporal relationship and estimate the incidence of HIV infection among women using and not using hormonal contraceptive methods.

  10. A comprehensive mapping of the current capacity for human nutrition training in Cameroon

    Directory of Open Access Journals (Sweden)

    Roger Sodjinou

    2016-01-01

    Full Text Available Background: There is consensus among stakeholders in Cameroon on the need to develop and strengthen human resource capacity for nutrition. This study was conducted to provide a comprehensive mapping of the current capacity for tertiary-level human nutrition training in Cameroon. Design: Participating institutions included university-level institutions offering dedicated nutrition degree programs or other programs in which nutrition courses were taught. A semi-structured questionnaire administered during in-person interviews was used to collect data on existing programs and content of training curricula. Nutrition curricula were reviewed against the following criteria: intended objectives, coverage of nutrition topics, and teaching methods. Results: In total, five nutrition degree programs (four undergraduate programs and one master's program were identified. Three additional programs were about to be launched at the time of data collection. We did not find any doctorate degree programs in nutrition. All the undergraduate programs only had little focus on public health nutrition whereas the master's program in our sample offered a good coverage of all dimensions of human nutrition including basic and applied nutrition. The predominant teaching method was didactic lecture in all the programs. We did not find any formal documentation outlining the competencies that students were expected to gain upon completion of these programs. Nutrition courses in agricultural and health schools were limited in terms of contact hours and scope. Public health nutrition was not covered in any of the health professional schools surveyed. We found no institution offering in-service nutrition training at the time of the study. Conclusions: Based on our findings, we recommend that nutrition training programs in Cameroon be redesigned to make them more responsive to the public health needs of the country.

  11. Forest Conversion, Agricultural Transitions and the Influence of Multi-scale Market Factors in Southwest Cameroon

    Science.gov (United States)

    Ordway, E.; Lambin, E.; Asner, G. P.

    2015-12-01

    The changing structure of demand for commodities associated with food security and energy has had a startling impact on land use change in tropical forests in recent decades. Yet, the composition of conversion in the Congo basin remains a major uncertainty, particularly with regards to the scale of drivers of change. Owing to rapid expansion of production globally and longstanding historical production locally in the Congo basin, oil palm offers a lens through which to evaluate local land use decisions across a spectrum of small- to large-scales of production as well as interactions with regional and global supply chains. We examined the effect of global commodity crop expansion on land use change in Southwest Cameroon using a mixed-methods approach to integrate remote sensing, field surveys and socioeconomic data. Southwest Cameroon (2.5 Mha) has a long history of large- and small-scale agriculture, ranging from mixed crop subsistence agriculture to large monocrop plantations of oil palm, cocoa, and rubber. Trends and spatial patterns of forest conversion and agricultural transitions were analyzed from 2000-2015 using satellite imagery. We used economic, demographic and field survey datasets to assess how regional and global market factors and local commodity crop decisions affect land use patterns. Our results show that oil palm is a major commodity crop expanding in this region, and that conversion is occurring primarily through expansion by medium-scale producers and local elites. Results also indicate that global and regional supply chain dynamics influence local land use decision making. This research contributes new information on land use patterns and dynamics in the Congo basin, an understudied region. More specifically, results from this research contribute information on recent trends of oil palm expansion in Cameroon that will be used in national land use planning strategies.

  12. Cure or control: complying with biomedical regime of diabetes in Cameroon

    Directory of Open Access Journals (Sweden)

    Unwin Nigel

    2008-02-01

    Full Text Available Abstract Background The objective of the study was to explore the cultural aspect of compliance, its underlying principles and how these cultural aspects can be used to improve patient centred care for diabetes in Cameroon. Methods We used participant observation to collect data from a rural and an urban health district of Cameroon from June 2001 to June 2003. Patients were studied in their natural settings through daily interactions with them. The analysis was inductive and a continuous process from the early stages of fieldwork. Results The ethnography revealed a lack of basic knowledge about diabetes and diabetes risk factors amongst people with diabetes. The issue of compliance was identified as one of the main themes in the process of treating diabetes. Compliance emerged as part of the discourse of healthcare providers in clinics and filtered into the daily discourses of people with diabetes. The clinical encounters offered treatment packages that were socially inappropriate therefore rejected or modified for most of the time by people with diabetes. Compliance to biomedical therapy suffered a setback for four main reasons: dealing with competing regimes of treatment; coming to terms with biomedical treatment of diabetes; the cost of biomedical therapy; and the impact of AIDS on accepting weight loss as a lifestyle measure in prescription packages. People with diabetes had fears about and negative opinions of accepting certain prescriptions that they thought could interfere with their accustomed social image especially that which had to do with bridging their relationship with ancestors and losing weight in the era of HIV/AIDS. Conclusion The cultural pressures on patients are responsible for patients' partial acceptance of and adherence to prescriptions. Understanding the self-image of patients and their background cultures are vital ingredients to improve diabetes care in low-income countries of Sub-Sahara Africa like Cameroon.

  13. Petroleum geology of the deltaic sequence, Rio Del Rey basin, offshore Cameroon

    Energy Technology Data Exchange (ETDEWEB)

    Coughlin, R.M.; Bement, W.O.; Maloney, W.V. (Pecten International Company, Houston, TX (United States))

    1993-09-01

    The Rio Del Rey Basin of offshore Cameroon comprises the easternmost portion of the Niger delta complex. In the delta flank setting, the overall package is thinner and stratigraphic correlation simpler than in the depocenter to the west so the distribution of reservoirs and seals is well defined. Productive reservoirs are shallow, typically less than 2000 m, and mostly hydropressured to slightly overpressured. Reservoir properties generally are excellent and seismic bright-spot technology has played a major role in exploration and development efforts. Rio Del Rey is characterized by three main structural styles from north to south: (1) detachment-based growth faults, (2) highly faulted, mobile shale cored domes and ridges, and (3) toe thrusts and folds. Virtually all individual traps are fault dependent and lack of sufficient internal seals in sand-rich wave-dominated deltaic sequences can limit the objective window. Most fields are downthrown fault traps in which hanging-wall reservoirs are effectively sealed against older prodelta and marine shales. All large oil fields are located in the dome and ridge province and are potential analogs for similar structures now being explored on the upper slope off Nigeria. The best quality source rocks identified thus far are Paleocene to Eocene marine shales. Oil vs. gas distribution in the basin is a function of variations in the kerogen type, organic richness, and maturity of these source rocks. A significant quantity of the gas found to date in Rio Del Rey is biogenic in origin. The Cameroon charge model may aid in better understanding hydrocarbon distribution on offshore Nigeria, where the Miocene deltaic section is much thicker and potential Paleocene-Eocene source rocks likely are unpenetrated. The shallow deltaic play in Cameroon is relatively mature. Future exploration likely will focus on identifying deeper, nonbright-spot-supported opportunities including potential stratigraphic traps.

  14. Molecular Species Delimitation and Morphology of Aquatic and Sub-Aquatic Bugs (Heteroptera in Cameroon.

    Directory of Open Access Journals (Sweden)

    Solange Meyin A Ebong

    Full Text Available Aquatic and semi-aquatic bugs (Heteroptera represent a remarkable diversity and a resurging interest has been given to documenting at the species level these insects inhabiting Cameroon in Central Africa due to their potential implication in the transmission of the bacterium Mycobacterium ulcerans, the causal agent of Buruli ulcer, an emerging human disease. A survey was carried out over two years in Cameroon. Morphological analyses were done in two steps. A first step consisted in separating the specimens based on broadly shared characters into morphotypes. The specimens were then separated into two independent batches containing each the same representation of each morphotype. One batch (309 specimens was used by taxonomy experts on aquatic bugs for species level identification and/or to reconcile nymph with their corresponding adult species. The second batch (188 specimens was used to define species based on the COI DNA sequences (standard sequence used for "DNA barcoding" and using the Automatic Barcode Gap Discovery (ABGD method. The first morphological analysis step separated the specimens into 63 different morphotypes (49 adults and 14 nymphs, which were then found to belong to 54 morphological species in the infra-orders Gerromorpha and Nepomorpha based on the species-level morphological identification, and 41-45 putative molecular species according to the gap value retained in the ABGD. Integrating morphology and "DNA barcoding" reconciled all the specimens into 62 aquatic bug species in Cameroon. Generally, we obtained a good congruence between species a priori identified based on morphology from adult morphotypes and molecular putative species. Moreover, molecular identification has allowed the association of 86% of nymphs with adults. This work illustrates the importance of integrative taxonomy.

  15. Spatio-temporal evolution of the Tuxtla Volcanic Field

    Science.gov (United States)

    Kobs Nawotniak, S. E.; Espindola, J.; Godinez, L.

    2010-12-01

    Mapping of the Tuxtla Volcanic Field (TVF), located in Veracruz, Mexico, through the use of digital elevation models, aerial photography, and field confirmation has found 353 distinct cones, 4 large composite volcanoes, and 42 maars. Eruptive activity in the TVF began in the late Miocene, underwent a quiescent period approximately 2.6-0.8 Ma, and continues into historic times with the most recent eruption occurring at San Martín Tuxtla volcano in 1793. The covariance of the minimum cone separation in the TVF indicates that, despite the influence of clear vent alignments following regional faulting trends, the field as a whole is anticlustered. Dividing the cones by morphometric age shows that while the older cones have an anti-clustered distribution, the younger cones (Catemaco. These areas of concentrated volcanism roughly correspond to the locations of two gravity anomalies previously identified in the area. While the average height/width ratio is equal between the two clusters, the cones in the eastern group are significantly smaller than their counterparts in the western group. The maars of the TVF are mostly located within the younger volcanic series, west of Laguna Catemaco, and have an anticlustered distribution; many of the maars are evenly spaced along curved lines, where they are weakly grouped according to crater diameter. Results indicate volcanism TVF has undergone continued spatial restriction over time, concentrating in the western half of the TVF with the onset of the eruption of the younger volcanic series 0.8 Ma and further contracting along the principle fault system within the last 50 Ka.

  16. Risk Factors for Birth Asphyxia in an Urban Health Facility in Cameroon

    OpenAIRE

    Chiabi, Andreas; Nguefack, Seraphin; Evelyne MAH; NODEM, Sostenne; Mbuagbaw, Lawrence; Mbonda, Elie; TCHOKOTEU, Pierre-Fernand; Anderson DOH

    2013-01-01

    How to Cite This Article: Chiabi A, Nguefack S, Mah E, Nodem S, Mbuagbaw L, Mbonda E, Tchokoteu PF, Doh A. Risk Factors for Birth Asphyxia in an Urban Health Facility in Cameroon. Iran J Child Neurol. 2013 Summer; 7(3):46-54.ObjectiveThe World Health Organization (WHO) estimates that 4 million children are born with asphyxia every year, of which 1 million die and an equal number survive with severe neurologic sequelae. The purpose of this study was to identify the risk factors of birth asphyx...

  17. Determinants of outcome of children with type 1 diabetes in the North West Region of Cameroon

    OpenAIRE

    Niba, Loveline Lum

    2016-01-01

    Background: In sub-Saharan Africa the prognosis of children with type 1 diabetes is poor. Many are not diagnosed and those that are diagnosed have a reduced life expectancy (less than one year). This study set out to identify the factors that predict glucose control in children and adolescents with type 1 diabetes in the North West Region of Cameroon. Methods: A hospital based cross-sectional study involving 76 children/adolescents (41 girls and 35 boys, mean age of 15.1 ± 3.1 years) suf...

  18. Neotectonic earth movements related to the 1999 eruption of Cameroon Mountain, West Africa

    Institute of Scientific and Technical Information of China (English)

    C. E. Suh; S. N. Ayonghe; E. S. Njumbe

    2001-01-01

    @@ The 1999 eruption of Cameroon Mountain was restricted to two sites and controlled by fissures subparallel to one another. Brittle failure, vertical displacement, horizontal displacement and ground deflation are the main types of ground deformation around these sites. The eruptive vents at both sites have a NE-SW trend parallel to the principal eruptive fissures and brittle discontinuities in rock bodies in this vicinity. SH (greatest horizontal stress) is inferred to have a SW-NE trend parallel to the direction of vent migration and fracture propagation.

  19. Cameroon mid-level providers offer a promising public health dentistry model

    Directory of Open Access Journals (Sweden)

    Achembong Leo

    2012-11-01

    Full Text Available Background Oral health services are inadequate and unevenly distributed in many developing countries, particularly those in sub-Saharan Africa. Rural areas in these countries and poorer sections of the population in urban areas often do not have access to oral health services mainly because of a significant shortage of dentists and the high costs of care. We reviewed Cameroon’s experience with deploying a mid-level cadre of oral health professionals and the feasibility of establishing a more formal and predictable role for these health workers. We anticipate that a task-shifting approach in the provision of dental care will significantly improve the uneven distribution of oral health services particularly in the rural areas of Cameroon, which is currently served by only 3% of the total number of dentists. Methods The setting of this study was the Cameroon Baptist Convention Health Board (BCHB, which has four dentists and 42 mid-level providers. De-identified data were collected manually from the registries of 10 Baptist Convention clinics located in six of Cameroon’s 10 regions and then entered into an Excel format before importing into STATA. A retrospective abstraction of all entries for patient visits starting October 2010, and going back in time until 1500 visits were extracted from each clinic. Results This study showed that mid-level providers in BCHB clinics are offering a full scope of dental work across the 10 clinics, with the exception of treatment for major facial injuries. Mid-level providers alone performed 93.5% of all extractions, 87.5% of all fillings, 96.5% of all root canals, 97.5% of all cleanings, and 98.1% of all dentures. The dentists also typically played a teaching role in training the mid-level providers. Conclusions The Ministry of Health in Cameroon has an opportunity to learn from the BCHB model to expand access to oral health care across the country. This study shows the benefits of using a simple, workable, low

  20. [Commercial sexual exploitation of minor girls. A multifocal, exploratory and prospective study in Cameroon].

    Science.gov (United States)

    Mbassa Menick, D; Dassa, K S; Kenmogne, J B; Abanda Ngon, G

    2009-02-01

    To obtain reliable information on commercial sexual exploitation of minor girls under the age of 21, a multifocal, exploratry and prospective using a questionnaire was undertaken in Cameroon. This investigation was initiated and funded by the Cercle International pour la Promotion de la Création (CIPCRE) and carried out by the Cameroon Society for the Prevention of Child Abuse and Neglect (CASPCAN). The survey was performed during the last quarter of year 2004 in four major cities of Cameroon, i.e. Yaoundé, Douala, Bamenca and Bafoussam. Of the 800 questionnaires that were distributed, 722 were considered as suitable for analysis (90.3%). A total of 291 minor girls were victims of commercial sexual exploitation, i.e., 40% of the population studied. The mean age of the victims was 16.6 years (range, 9-20 years). The main reason given for entering prostitution was poverty. The victims were fairly well educated but the level of instruction was not sufficient to find a job paying an income comparable to prostitution. Many were from large families (mean, 7.1 children). The victims' family was monogamous in 40.2% of cases, polygamous in 24.4%, and monoparental in 35.4%. Eighty percent of the victims already had run away from home at least once due to problems in their families ranging from severe corporal punishment (25.8%) and mistreatment linked to parental alcohol and drug abuse to forced early marriage (27.5%) and intrafamilial sexual abuse. A large proportion of the victims (36.4%) were mothers who could not attend school and could not find work. Many victims were completely neglected by their own parents with 43.4% of parents being aware of the activities of their daughters but only 10.6% being opposed to it. Most (78.5%) had good knowledge of the risk of HIV and used condoms regular. These results confirms the general hypothesis of the authors that commercial exploitation of minor girls is widespread in Cameroon. The authors recommend development of a national

  1. Cryogenic Origin for Mars Analog Carbonates in the Bockfjord Volcanic Complex Svalbard (Norway)

    Science.gov (United States)

    Amundsen, H. E. F.; Benning, L.; Blake, D. F.; Fogel, M.; Ming, D.; Skidmore, M.; Steele, A.

    2011-01-01

    The Sverrefjell and Sigurdfjell eruptive centers in the Bockfjord Volcanic Complex (BVC) on Svalbard (Norway) formed by subglacial eruptions ca. 1 Ma ago. These eruptive centers carry ubiquitous magnesian carbonate deposits including dolomitemagnesite globules similar to those in the Martian meteorite ALH84001. Carbonates in mantle xenoliths are dominated by ALH84001 type carbonate globules that formed during quenching of CO2-rich mantle fluids. Lava hosted carbonates include ALH84001 type carbonate globules occurring throughout lava vesicles and microfractures and massive carbonate deposits associated with vertical volcanic vents. Massive carbonates include < or equal 5 cm thick magnesite deposits protruding downwards into clear blue ice within volcanic vents and carbonate cemented lava breccias associated with volcanic vents. Carbonate cements comprise layered deposits of calcite, dolomite, huntite, magnesite and aragonite associated with ALH84001 type carbonate globules lining lava vesicles. Combined Mossbauer, XRD and VNIR data show that breccia carbonate cements at Sverrefjell are analog to Comanche carbonates at Gusev crater.

  2. Women Farmers' Perceptions of the Economic Problems Influencing Their Productivity in Agricultural Systems: Meme Division of the Southwest Province, Cameroon.

    Science.gov (United States)

    Endeley, Joyce B.

    Women farmers produce about 60% of the food in Cameroon, but face more problems and constraints than men in performing their agricultural activities. Cash crop farmers (mostly men) are the targeted beneficiaries of government and international aids, and have better access to extension services, loans, subsidized production input (herbicides,…

  3. Common challenges in gum arabic production and commercialization in West Africa: a comparative study of Cameroon, Niger and Senegal

    NARCIS (Netherlands)

    Mujawamariya, G.; Madi, O.P.; Zoubeirou, A.M.; Sene, A.; Maisharou, A.; Haese, D' M.F.C.

    2013-01-01

    As gum arabic is widely used in food and non-food industries, demand is high all over the world. Still, smaller production countries in West Africa such as Cameroon, Niger and Senegal seem to have so many difficulties producing and commercializing gum arabic that their market shares have declined si

  4. Molecular Epidemiology of HIV Type 1 CRF02_AG in Cameroon and African Patients Living in Italy

    Science.gov (United States)

    Véras, Nazle Mendonca Collaço; Santoro, Maria Mercedes; Gray, Rebecca R.; Tatem, Andrew J.; Presti, Alessandra Lo; Olearo, Flaminia; Cappelli, Giulia; Colizzi, Vittorio; Takou, Desiré; Torimiro, Judith; Russo, Gianluca; Callegaro, Annapaola; Salpini, Romina; D'Arrigo, Roberta; Perno, Carlo-Federico; Goodenow, Maureen M.; Ciccozzi, Massimo

    2011-01-01

    Abstract HIV-1 CRF02_AG accounts for >50% of infected individuals in Cameroon. CRF02_AG prevalence has been increasing both in Africa and Europe, particularly in Italy because of migrations from the sub-Saharan region. This study investigated the molecular epidemiology of CRF02_AG in Cameroon by employing Bayesian phylodynamics and analyzed the relationship between HIV-1 CRF02_AG isolates circulating in Italy and those prevalent in Africa to understand the link between the two epidemics. Among 291 Cameroonian reverse transcriptase sequences analyzed, about 70% clustered within three distinct clades, two of which shared a most recent common ancestor, all related to sequences from Western Africa. The major Cameroonian clades emerged during the mid-1970s and slowly spread during the next 30 years. Little or no geographic structure was detected within these clades. One of the major driving forces of the epidemic was likely the high accessibility between locations in Southern Cameroon contributing to the mobility of the population. The remaining Cameroonian sequences and the new strains isolated from Italian patients were interspersed mainly within West and Central African sequences in the tree, indicating a continuous exchange of CRF02_AG viral strains between Cameroon and other African countries, as well as multiple independent introductions in the Italian population. The evaluation of the spread of CRF02_AG may provide significant insight about the future dynamics of the Italian and European epidemic. PMID:21453131

  5. SMALL Savannah : an information system for the integrated analysis of land use change in the Far North of Cameroon

    NARCIS (Netherlands)

    Fotsing, Eric

    2009-01-01

    SMALL Savannah is an Environmental Information System designed for the integrated analysis and sustainable land management in the savannas region of the Far North of Cameroon. This system combines an observation and spatial analysis module for the representation of phenomena from various geographic

  6. English-Medium Instruction in an English-French Bilingual Setting: Issues of Quality and Equity in Cameroon

    Science.gov (United States)

    Kuchah, Kuchah

    2016-01-01

    Despite its multilingual nature Cameroon's educational system provides for full immersion into either French-medium or English-medium education from the first year schooling. Following political tensions in the early 1990s the country decided to reaffirm its commitment to promote bilingualism in the educational system with the outcome being the…

  7. The determinants of the willingness-to-pay for community-based prepayment scheme in rural Cameroon.

    Science.gov (United States)

    Donfouet, Hermann Pythagore Pierre; Makaudze, Ephias; Mahieu, Pierre-Alexandre; Malin, Eric

    2011-09-01

    In rural Cameroon, many people have no access to quality healthcare services. This is largely attributed to lack of private out-of-pocket payment to finance healthcare services. A community-based prepayment health insurance scheme may be implemented to improve healthcare access in rural areas. This study examines the determinants of willingness-to-pay for a community-based prepayment healthcare system using a contingent valuation method conducted in rural Cameroon. To mitigate potential hypothetical bias, a consequential script is introduced in the questionnaire. The results indicate age, religion, profession, knowledge of community-based health insurance, awareness of usual practice in rural areas, involvement in association and disposable income are the key determinants of willingness to pay for a prepayment health scheme. On average, willingness to pay for the scheme by rural households is 1011 CFA francs/person/month (2.15 US dollars). The results underlie two important implications: first, there is substantial demand for a community healthcare prepayment scheme by rural poor households in Cameroon; second, rural households are averse to health shocks and hence they are willing to sacrifice monthly premium payments to protect themselves (and their households) from unforeseen health-related risks. If government could engage in social marketing strategies such as mass media campaigns and awareness, this could prove vital for encouraging participation by the rural poor in healthcare prepayment scheme in Cameroon.

  8. Crisis and neoliberal reforms in Africa : civil society and agro-industry in anglophone Cameroon's plantation economy

    NARCIS (Netherlands)

    Konings, P.J.J.

    2011-01-01

    This book discusses the consequences of the economic and financial crisis that befell the Cameroonian agro-industrial sector in the 1980s, using as a case study the plantation economy of the anglophone region of Cameroon. Two agro-industrial enterprises have dominated the plantation sector: a huge p

  9. Ternstroemia cameroonensis (Ternstroemiaceae), a new medicinally important species of montane tree, nearly extinct in the Highlands of Cameroon

    NARCIS (Netherlands)

    Cheek, M.; Tchiengue, B.; Tacham, W.N.

    2017-01-01

    Ternstroemia cameroonensis sp. nov. (Ternstroemiaceae) is formally described from the Highlands of Cameroon and its conservation status is assessed as Critically Endangered using the IUCN 2012 standard. This is the third species of Ternstroemia known from Africa. The species is unusual in its genus

  10. Breeding Biology and Diet of the African Swallow-Tailed Kite (Chelictinia riocourii) in Senegal and Cameroon

    NARCIS (Netherlands)

    Buij, R.; Cavaillés, S.; Mullié, W.C.

    2013-01-01

    We studied the breeding biology of the African Swallow-tailed Kite (Chelictinia riocourii) in two study areas located 3400 km apart in the central (Cameroon) and western (Senegal) portions of the species' breeding range. With 110 nests in 2.8 km2 of suitable breeding habitat, Kousmar islet (23 km2)

  11. BREEDING BIOLOGY AND DIET OF THE AFRICAN SWALLOW-TAILED KITE (CHELICTINIA RIOCOURII) IN SENEGAL AND CAMEROON

    NARCIS (Netherlands)

    Buij, Ralph; Cavailles, Simon; Mullie, Wim C.

    2013-01-01

    We studied the breeding biology of the African Swallow-tailed Kite (Chelictinia riocourii) in two study areas located 3400 km apart in the central (Cameroon) and western (Senegal) portions of the species' breeding range. With 110 nests in 2.8 km(2) of suitable breeding habitat, Kousmar islet (23 km(

  12. Preliminary studies of pest constraints to cotton seedlings in a direct seeding mulch-based system in Cameroon

    NARCIS (Netherlands)

    Brevault, T.; Guibert, H.; Naudin, K.

    2009-01-01

    The present study evaluated the pest constraints of an innovative crop management system in Cameroon involving conservation tillage and direct seeding mulch-based strategies. We hypothesized that the presence of mulch (i) would support a higher density of phytophagous arthropods particularly millipe

  13. Empowering Women and Ethnic Minority Groups to Collectively Market non Timber Forest Products from Community Forests in Cameroon

    NARCIS (Netherlands)

    Eijnatten, van Judith; Mala, William Armand; Ingram, V.J.; Belibi, M.B.

    2016-01-01

    Community forestry (CF) was introduced in Cameroon in 1994 as a way to reduce poverty and enhance sustainable forest management. CF activities have primarily focused on timber exploitation rather than non-timber forest product (NTFP) collection processing or marketing. The study reports on a two yea

  14. Quantitative Effects of Early and Late Blights on Tomato Yields in Cameroon

    Directory of Open Access Journals (Sweden)

    Fontem, DA.

    2003-01-01

    Full Text Available Early blight caused by Alternaria solani and late blight caused by Phytophthora infestans are the major diseases of tomato (Lycopersicon esculentum in Cameroon. The effect of both diseases on fruit yield was evaluated during the 1995 growing season in Dschang, Cameroon.Ten varieties were planted in the first trial (March-July and nine in the second (July- November. In both trials, plots were sprayed weekly with Ridomil Plus (2.0 kg/ha before flowering and with maneb (1.6 kg/ha after flowering. Early blight was more severe in the early part of the first trial, while late blight caused most damage during the second. Marketable yields varied according to variety. High yields in sprayed plots were obtained in Dona F1 (61.63 t/ha and Heinz 1370 (68.24 t/ha during the first trial, and in Fline (58.35 t/ha, Mecline (64.25 t/ha, and Moboline (55.16 t/ha during the second trial. Percent fruit infection in sprayed plots caused by both diseases varied according to variety from 12 to 65% in the first season and from 14 to 52% in the second, while losses in marketable yields for both blights were as high as 100% in unsprayed plots.

  15. Sexual vulnerability and HIV seroprevalence among the deaf and hearing impaired in Cameroon

    Directory of Open Access Journals (Sweden)

    Touko Adonis

    2010-02-01

    Full Text Available Abstract Background This quantitative cross-sectional study examines sexual behaviour of a target group of hearing-impaired persons in Yaounde, the capital city of the Republic of Cameroon. It measures their HIV prevalence to enable assessment of their sexual vulnerability and to help reduce the gap in existing HIV serology data among people with disabilities in general and the deaf in particular. Methods The snowball sampling procedure was adopted as an adequate approach to meet this hard-to-reach group. A total of 118 deaf participants were interviewed for the behavioural component, using sign language as a means of data collection, while 101 participants underwent HIV serology testing. Descriptive analyses were done for behavioural data with Epi info software, while sera were tested by health personnel, using rapid and confirmation test reagents. Results From the results, it was clear that the hearing impaired were highly involved in risky sexual practices, as observed through major sexual indicators, such as: age at first sexual intercourse; condom use; and knowledge of sexually transmitted infections and AIDS. Furthermore, it was noted that the HIV prevalence rate of the hearing impaired in the capital of Cameroon was 4%, close to the prevalence in the city's general population (4.7%. Conclusions Such results suggest that there is a need for in-depth behavioural research and serological studies in this domain to better understand the determinants of risky sexual behaviour among the hearing impaired, and to propose operational prevention approaches for this group.

  16. Producers’ motivation for collective action for kola production and marketing in Cameroon

    Directory of Open Access Journals (Sweden)

    Steven Franzel

    2012-04-01

    Full Text Available Collective action has been used as a strategy to improve the benefits of smallholder producers of kola nuts in Cameroon. Despite demonstrated benefits, not all producers are involved in the collective action. The presented study used a modified Technology Acceptance Model (TAM namely the Collective Action Behaviour model (CAB model to analyse kola producers’ motivation for collective action activities. Five hypotheses are formulated and tested using data obtained from 185 farmers who are involved in kola production and marketing in theWestern highlands of Cameroon. Results which were generated using Partial Least Squares (PLS approach for Structural Equation Modelling (SEM showed that farmers’ intrinsic motivators and ease of use influenced their behavioural intent to join a group marketing activities. The perceived usefulness that was mainly related to the economic benefits of group activities did not influence farmers’ behavioural intent. It is therefore concluded that extension messages and promotional activities targeting collective action need to emphasise the perceived ease of use of involvement and social benefits associated with group activities in order to increase farmers’ participation.

  17. Ethnomedicinal Plants Used by Traditional Healers to Treat Oral Health Problems in Cameroon

    Science.gov (United States)

    Ashu Agbor, Michael; Naidoo, Sudeshni

    2015-01-01

    Objectives. The objective of the study was to determine the therapeutic methods used by traditional healers to treat oral diseases in Cameroon. Methods. A total of 200 traditional healers with a mean age of 50.4 ± 14.2 years from all the provinces of Cameroon were studied using questionnaires. Information elicited was the local names of the medicinal plants used for the management of oral problems, their routes of administration, and methods of usage. Identification of live or dried plants or photographs of sample of the plants was done by a taxonomist. Results. The majority of the participants were males urban dwellers aged 41–50 years, 112 (56.0%) practice as herbalists and 56 (28.0%) were trained on medications preservation, 77(56.6%) treat diseases inside or outside the mouth, and 9.0% reported being specialist in oral diseases treatment. Of the 52 plants identified, 48 are used in the management of toothache, sore throat, mouth sores, abscess, broken tooth and jaw, tooth sensitivity, mouth thrush, dental caries, gingivitis, sinusitis, tonsillitis, xerostomia, oral syphilis, oral cancer, TMJ pain, halitosis, and tooth bleaching and 4 plants are used for dental extraction. Roots, leaves, and bark were the parts of plants used and some minerals as adjuncts. Conclusion. The study provides comprehensive information on therapeutic methods employed by traditional healers for the treatment of oral diseases. PMID:26495020

  18. Implications of the cattle trade network in Cameroon for regional disease prevention and control

    Science.gov (United States)

    Motta, Paolo; Porphyre, Thibaud; Handel, Ian; Hamman, Saidou M.; Ngu Ngwa, Victor; Tanya, Vincent; Morgan, Kenton; Christley, Rob; Bronsvoort, Barend M. deC.

    2017-01-01

    Movement of live animals is a major risk factor for the spread of livestock diseases and zoonotic infections. Understanding contact patterns is key to informing cost-effective surveillance and control strategies. In West and Central Africa some of the most rapid urbanization globally is expected to increase the demand for animal-source foods and the need for safer and more efficient animal production. Livestock trading points represent a strategic contact node in the dissemination of multiple pathogens. From October 2014 to May 2015 official transaction records were collected and a questionnaire-based survey was carried out in cattle markets throughout Western and Central-Northern Cameroon. The data were used to analyse the cattle trade network including a total of 127 livestock markets within Cameroon and five neighboring countries. This study explores for the first time the influence of animal trade on infectious disease spread in the region. The investigations showed that national borders do not present a barrier against pathogen dissemination and that non-neighbouring countries are epidemiologically connected, highlighting the importance of a regional approach to disease surveillance, prevention and control. Furthermore, these findings provide evidence for the benefit of strategic risk-based approaches for disease monitoring, surveillance and control, as well as for communication and training purposes through targeting key regions, highly connected livestock markets and central trading links. PMID:28266589

  19. Implications of the cattle trade network in Cameroon for regional disease prevention and control

    Science.gov (United States)

    Motta, Paolo; Porphyre, Thibaud; Handel, Ian; Hamman, Saidou M.; Ngu Ngwa, Victor; Tanya, Vincent; Morgan, Kenton; Christley, Rob; Bronsvoort, Barend M. Dec.

    2017-03-01

    Movement of live animals is a major risk factor for the spread of livestock diseases and zoonotic infections. Understanding contact patterns is key to informing cost-effective surveillance and control strategies. In West and Central Africa some of the most rapid urbanization globally is expected to increase the demand for animal-source foods and the need for safer and more efficient animal production. Livestock trading points represent a strategic contact node in the dissemination of multiple pathogens. From October 2014 to May 2015 official transaction records were collected and a questionnaire-based survey was carried out in cattle markets throughout Western and Central-Northern Cameroon. The data were used to analyse the cattle trade network including a total of 127 livestock markets within Cameroon and five neighboring countries. This study explores for the first time the influence of animal trade on infectious disease spread in the region. The investigations showed that national borders do not present a barrier against pathogen dissemination and that non-neighbouring countries are epidemiologically connected, highlighting the importance of a regional approach to disease surveillance, prevention and control. Furthermore, these findings provide evidence for the benefit of strategic risk-based approaches for disease monitoring, surveillance and control, as well as for communication and training purposes through targeting key regions, highly connected livestock markets and central trading links.

  20. Farmer's Perception and Adoption of New Aquaculture Technologies in the Western Highlands of Cameroon

    Directory of Open Access Journals (Sweden)

    Njankoua Wandji, D.

    2012-01-01

    Full Text Available Like other African countries, Cameroon is struggling to meet the food needs of its population. There are several possible solutions to this problem, such as the import of agricultural produce and increasing national production. In terms of fishery products (fish, shrimps, etc., it would not be easy to increase national production, due to the various constraints inherent in the sector and national industry, as well as low availability of farming areas. Fish farming is one of the solutions recommended as a sustainable method of producing an adequate supply of fish (farming fish in ponds. The main objective of this study is to highlight and analyse the socio-economic obstacles that are holding back the development of fish farming in the West Cameroon. Using the univariate dichotomous LOGIT model, this study has made it possible to identify the key determinants affecting the adoption of fish farming. The results indicate that its strong commercial orientation, coupled with the positive perception of its profitability, frequent contact, extension and level of education are the main determinants for the adoption of fish farming.

  1. Geographic Distribution of Childbirth among Adolescents in Cameroon from 2003 to 2005

    Directory of Open Access Journals (Sweden)

    P. M. Tebeu

    2010-01-01

    Full Text Available Objective. To determine the frequency and the trend of adolescents (10–19 years in childbirth within a period of 3 years in referral maternity units in Cameroon. Method. Descriptive and retrospective study for a 3-year period (2003–2005 in referral maternity units headed by a qualified Obstetrician-Gynecologist. We analyzed the trend and geographic distribution of 8222 adolescent deliveries over 3 years. Epi Info 3.5 software was used for data analysis. Chi square test for trend was used to assess the contribution of adolescent deliveries over years. The trend was considered significant if P<.05. Results. During the period of the study, there was a total of 8387 deliveries. We excluded 165 women because of lack of information about age. We therefore included a total of 8222 adolescent deliveries. Overall, the contribution of adolescents to deliveries ranged from 6.87% to 26.51%, depending on the region with a national mean of 14.23%. Adolescents aged 16 or less contributed to 2.82% of deliveries while those aged from 17 to 19 contributed to 11.41%. The contribution of adolescents to deliveries decreased significantly over 3 years (P<.0001. Conclusion. The study underscores the importance of Public Health programs in strengthening maternity services for adolescents in Cameroon while taking into consideration geographic differences.

  2. Ethnomedicinal Plants Used by Traditional Healers to Treat Oral Health Problems in Cameroon

    Directory of Open Access Journals (Sweden)

    Michael Ashu Agbor

    2015-01-01

    Full Text Available Objectives. The objective of the study was to determine the therapeutic methods used by traditional healers to treat oral diseases in Cameroon. Methods. A total of 200 traditional healers with a mean age of 50.4±14.2 years from all the provinces of Cameroon were studied using questionnaires. Information elicited was the local names of the medicinal plants used for the management of oral problems, their routes of administration, and methods of usage. Identification of live or dried plants or photographs of sample of the plants was done by a taxonomist. Results. The majority of the participants were males urban dwellers aged 41–50 years, 112 (56.0% practice as herbalists and 56 (28.0% were trained on medications preservation, 77(56.6% treat diseases inside or outside the mouth, and 9.0% reported being specialist in oral diseases treatment. Of the 52 plants identified, 48 are used in the management of toothache, sore throat, mouth sores, abscess, broken tooth and jaw, tooth sensitivity, mouth thrush, dental caries, gingivitis, sinusitis, tonsillitis, xerostomia, oral syphilis, oral cancer, TMJ pain, halitosis, and tooth bleaching and 4 plants are used for dental extraction. Roots, leaves, and bark were the parts of plants used and some minerals as adjuncts. Conclusion. The study provides comprehensive information on therapeutic methods employed by traditional healers for the treatment of oral diseases.

  3. Reducing Emissions from Deforestation and Degradation in Cameroon. Assessing costs and benefits

    Energy Technology Data Exchange (ETDEWEB)

    Bellassen, Valentin [Ecole Normale Superieure (ENS) (France); Gitz, Vincent [Centre International de Recherche sur l' Environnement et le Developpement (CIRED) (France)

    2008-12-01

    A new momentum is underway to account for emissions from 'avoided deforestation and degradation' at the United Nations Framework Convention on Climate Change (UNFCCC). This paper assesses the feasibility of one of the Reducing Emissions from Deforestation and Degradation (REDD) mechanisms currently discussed, namely that of 'Compensated Reduction', in the case of Cameroon. Here we assess the differential revenues that a farmer could get from 1 ha of land out of two alternative land-uses: shifting cultivation, the traditional land-use pattern in southern Cameroon, or carbon credits as compensation for the conservation of primary forest. It is found that a break-even price of USD 2.85/t of carbon dioxide equivalent would level shifting cultivation with 'Compensated Reduction'. This result suggests that at current carbon prices, and independently form variations in the discount rate, it could already be more profitable to preserve the primary forest rather than to log it in order to grow crops. (author)

  4. Sexual violence among host and refugee population in Djohong District, Eastern Cameroon.

    Science.gov (United States)

    Parmar, Parveen; Agrawal, Pooja; Greenough, P Gregg; Goyal, Ravi; Kayden, Stephanie

    2012-01-01

    The following is a population-based survey of the Central African Republic (CAR) female refugee population displaced to rural Djohong District of Eastern Cameroon and associated female Cameroonian host population to characterise the prevalence and circumstances of sexual violence. A population-based, multistage, random cluster survey of 600 female heads of household was conducted during March 2010. Women heads of household were asked about demographics, household economy and assets, level of education and sexual violence experienced by the respondent only. The respondents were asked to describe the circumstances of their recent assault. The lifetime prevalence of sexual violence among Djohong district female heads of household is 35.2% (95% CI 28.7-42.2). Among heads of household who reported a lifetime incident of sexual violence, 64.0% (95% CI 54.3-72.5) suffered sexual violence perpetrated by their husband or partner. Among the host population, 3.9% (95% CI 1.4-10.5) reported sexual violence by armed groups compared to 39.0% (95% CI 25.6-54.2) of female refugee heads of household. Women who knew how to add and subtract were less likely to report sexual violence during their lifetime (OR 0.16, 95% CI 0.08-0.34). Sexual violence is common among refugees and host population in Eastern Cameroon. Most often, perpetrators are partners/husbands or armed groups.

  5. A novel sickle cell mutation of yet another origin in Africa: the Cameroon type.

    Science.gov (United States)

    Lapouméroulie, C; Dunda, O; Ducrocq, R; Trabuchet, G; Mony-Lobé, M; Bodo, J M; Carnevale, P; Labie, D; Elion, J; Krishnamoorthy, R

    1992-05-01

    The sickle cell mutation (beta s) arose as at least three independent events in Africa and once in Asia, being termed the Senegal, Benin, Bantu and Indian types respectively. An investigation in Cameroon was carried out to determine whether the atypical sickle genes observed in the neighboring countries are the result of recombination or the presence of a sickle cell mutation of a different genetic origin. It was conducted on 40 homozygous SS patients followed at the Blood Transfusion Center in the capital city of Yaoundé. On 80 beta s chromosomes, 13 exhibited a novel polymorphic pattern that was observed three times in the homozygous state. This chromosome contains an A gamma T gene. The restriction fragment length polymorphism haplotype is different from all the other beta s chromosomes in both the 5' and 3' regions, but has previously been reported in sporadic cases. The (AT)8(T)5 sequence in the -500 region of the beta gene is specific and different from that of the Senegal, Benin, Bantu or Indian beta s genes. All the carriers of this specific chromosome belong to the Eton ethnic group and originate from the Sanaga river valley. This observation strongly argues for yet another independent origin of the sickle cell mutation in Africa, here referred to as the "Cameroon type". The Benin haplotype and a Benin/Bantu recombinant haplotype have been observed in the other studied populations: Ewondo, Bamiléké, Bassa, Yambassa and Boulou.

  6. A Crispy Delicacy: Augosoma Beetle as Alternative Source of Protein in East Cameroon

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    F. J. Muafor

    2014-01-01

    Full Text Available Despite the fact that the exoskeleton of the Augosoma centaurus (Dynastinae is hard and difficult to chew, this insect is often gathered in Eastern Cameroon for food in periods of availability. Nine ethnic groups in Eastern Cameroon were surveyed to understand the role of this insect in assuring food security, using quantitative and qualitative social science approaches. Both the larvae and adult stages of this beetle are habitually consumed in the areas studied. In total, about 65% of consumers prefer consuming the adults, while 35% prefer consuming the larvae. About 24% of consumers derive the same satisfaction from the consumption of Augosoma or other edible insects. Close to 39% of consumers prefer other edible insects to Augosoma, while 37% prefer the consumption of Augosoma to other edible insects. This beetle usually occurs at a period when other edible insects are not available, therefore constituting a good source of alternative protein in this region where poverty, poaching, and biodiversity erosion are still a major problem. Furthermore, the gathering of this beetle for food is equally a means of biological pest control of raffia plants and a tool to enhance community-based conservation of the areas global biodiversity.

  7. Campano-Maastrichtian foraminifera from onshore sediments in the Rio del Rey Basin, Southwest Cameroon

    Science.gov (United States)

    Njoh, Oliver Anoh; Victor, Obiosio; Christopher, Agyingi

    2013-03-01

    Campanian-Maastrichtian marine sediments outcrop in five genetically linked sedimentary basins along the West African coast in the Gulf of Guinea, from the Douala Basin in Cameroon to the Anambra Basin in Nigeria. These sediments in the more centrally located Rio del Rey Basin have been the least studied. Therefore, the geologic history of this region has merely been speculative. The Rio del Rey Basin like the adjacent Niger Delta is producing hydrocarbon from the offshore Tertiary sedimentary interval in which all studies have been focused, neglecting the onshore Cretaceous sediments. Outcrops in the basin are rare, small and highly weathered. Samples from some of these sediments have yielded a few Planktonic and dominantly benthonic foraminiferal assemblages. The long-ranging heterohelix and hedbergellids characterized the planktics while the species Afrobolivina afra which is a well known diagnostic taxon for Campanian-Maastrichtian sediments in West African basins clearly dominate the benthic assemblage. Its occurrence in association with other Upper Cretaceous forms such as Bolivina explicata, Praebulimina exiqua, Gabonita lata, Ammobaculites coprolithiformis amongst others, formed the basis on which this age was assigned to the sediments sampled from the Rio del Rey Basin. Hence, this work has undoubtedly established the much needed link in this regional geologic history and correlates these sediments with the Logbaba and Nkporo Formations in the Douala Basin in Cameroon and the southeastern Nigerian Sedimentary Basins. Thus, these units were all deposited during this same geologic period and probably controlled by the same geologic event.

  8. Adoption of the Tenera Hybrid of Oil Palm (Elaeis guineensis Jacquin. among Smallholder Farmers in Cameroon

    Directory of Open Access Journals (Sweden)

    Assoumou Mezui, MR.

    2013-01-01

    Full Text Available The adoption of the Tenera oil palm (Elaeis guineensis Jacq. type was studied by focusing on 208 family farmers in Cameroon. The "Average Treatment Effect" (ATE method was used. This method enables to estimate, by use of a Probit model, the effects created when a farmer is exposed to treatment (or intervention, which represents a source of improved oil palm planting material. According to the results, the estimated adoption rate for Tenera is highly significant (P< 0.05 for all the categories of producers, regardless of the supply source, which may be formal or informal. In addition, the main factors that significantly determine this adoption are: availability of arable land in forested areas and whether growers intend to increase the size of their plantations. However, the supply of pure planting material remains an important constraint because the other two types of oil palm (Dura and Pisifera which produce poor palm oil yields are still mistakenly planted on many family farms in Cameroon. Further studies will address this issue in the aim of identifying appropriate solutions.

  9. Rural local institutions and climate change adaptation in forest communities in Cameroon

    Directory of Open Access Journals (Sweden)

    H. Carolyn Peach Brown

    2015-06-01

    Full Text Available Surveys and interviews were used to understand community resilience in forest-dependent communities facing climate change in Cameroon. Surveys of 232 individuals showed a diversity of formal and informal institutions that relate to most aspects of rural life. Although direct activities related to climate change adaptation were limited, the activities and density of membership in rural local institutions could increase the community's adaptive capacity. Twenty-six semistructured interviews were also conducted with representatives of diverse local institutions who had some responsibility for agriculture, forests, conservation, or development. Local governmental institutions had not received any information from the national level and were limited in their knowledge of how to help communities respond to climate change. Although limited in their direct action on climate change, local nongovernmental organizations and international institutions act as bridging institutions with rural communities and could facilitate sharing of knowledge and innovation, thereby fostering resilience. Planning for climate change adaptation in Cameroon needs to build the capacity of diverse local institutions and improve the relationships between local and national-level adaptation planning.

  10. Serological and molecular tools to detect neurologic parasitic zoonoses in rural Cameroon.

    Science.gov (United States)

    Nkouawa, Agathe; Sako, Yasuhito; Moyou-Somo, Roger; Ito, Akira

    2011-11-01

    Parasitic helminthiases, such as toxocariasis, cysticercosis and paragonimiasis are a public health threat, since they can affect the brain leading to neurological disorders. Epilepsy and paragonimiasis are common in southwestern Cameroon. We reviewed the literature for studies using antigens to diagnose toxocariasis, cysticercosis, and paragonimiasis. Serology revealed that 61 (36.3%), 26 (15.5%) and 2 (1.2%) of 168 persons examined [78 males (15.2 +/- 8.2 years old), 90 females (12.9 +/- 5.9 years old), 143 persons < 20 years old] had antibody responses to toxocariasis, paragonimiasis and cysticercosis, respectively. Of the 14 people with epilepsy, 5 were seropositive for Toxocara antigens and 1 was positive for both Toxocara and Paragonimus antigens. Two children were serologically confirmed to have cysticercosis. Serologic screening for cysticercosis may be feasible to detect asymptomatic cysticercosis in children in endemic areas leading to early treatment. The causative Paragonimus species was confirmed to be P. africanus by molecular sequencing. Education, screening and confirmation test for these diseases may be needed for control in Cameroon.

  11. An Examination of Forest Certification Status among Logging Companies in Cameroon.

    Science.gov (United States)

    Nukpezah, Daniel; Alemagi, Dieudonne; Duguma, Lalisa; Minang, Peter; Mbosso, Charlie; Tchoundjeu, Zac

    2014-01-01

    This paper assesses the level of interest, awareness, and adoption of ISO 14001 and Forest Stewardship Council (FSC) certification schemes among logging companies in Cameroon. Eleven logging companies located in Douala in the Littoral Region of Cameroon were assessed through a structured interview using an administered questionnaire which was mostly analyzed qualitatively thereafter. The findings indicated that none of the companies was certified for ISO 14001; however 63.64% of them were already FSC-certified. Four companies (36.36%) were neither FSC- nor ISO 14001 EMS-certified. Among the factors found to influence the adoption rate was the level of awareness about ISO 14001 and FSC certification schemes. The main drivers for pursuing FSC certification were easy penetration into international markets, tax holiday benefits, and enhancement of corporate image of the logging companies through corporate social responsibility fulfillments. Poor domestic market for certified products was found to be the major impediment to get certified. To make logging activities more environmentally friendly and socially acceptable, logging companies should be encouraged to get certified through the ISO 14001 EMS scheme which is almost nonexistent so far. This requires awareness creation about the scheme, encouraging domestic markets for certified products and creating policy incentives.

  12. Correlates of Tax Compliance of Small and Medium Size Businesses in Cameroon

    Directory of Open Access Journals (Sweden)

    Oludele Akinloye Akinboade

    2015-12-01

    Full Text Available Taxation provides a predictable and stable flow of revenue to finance development objectives. This is important in a country like Cameroon that has serious challenges with meeting its development objectives. Small and medium enterprises (SMEs are significant for economic growth in the country, contributing as much as about 22 percent of the gross domestic product. SMEs generate taxable incomes. They also collect employment and value added taxes on behalf of the government. Taxation, however, imposes high cost to small businesses. SMEs are less tax compliant in comparison to large businesses. SMEs are considered the ‘hard to tax group from the informal sector.’ As such, the literature suggests that only a fraction of their taxable incomes is reported to tax authorities. Against this background, factors that correlate with tax compliance of 575 small and medium size companies in Cameroon are discussed from a survey of companies in the manufacturing and wholesale sectors. High registration cost and time-consuming processes promote tax non-compliance. The perception that tax system is corrupt discourages registration and filing compliance. When there are too many compliance hurdles, the probability of filing compliance is reduced. However, a fair and static system encourages filing and registration compliance. A clear and consistent tax system promotes filing compliance. Authorities that understand their responsibilities and are willing to respond to enquiries during the registration process promote tax compliance in general.

  13. Analysis and Application of Intelligent Transportation Systems to Taxi System in Cameroon

    Institute of Scientific and Technical Information of China (English)

    Nzegge Chantale Ebude; Wang Mingyan

    2007-01-01

    Most traffic control systems available in major cities in Cameroon are still out dated,make use of theories and models which are very slow to implement,waste resources and their efficiency is very low.Thus the number of road accidents encountered on our major highways and inter urban traffic networks has been increasing despite the various efforts made by government and certain NGO to synthesize road users on certain aspects of traffic control and safety road use.Taxis are not left out in the whole show and most of the blame always falls on them.The need to use available Information and Communication Technology ICT to improve on the control of traffic in inter urban cities and major highways is imperative.ITS optimizes the use of resources,reduce pollution,contribute to environmental protection and increases the national economy.This paper starts by giving a brief situation of the transportation system in Cameroon,its drawbacks and proposes an optimized ITS based system.

  14. Evaluation of new tools for malaria vector control in Cameroon: focus on long lasting insecticidal nets.

    Directory of Open Access Journals (Sweden)

    Josiane Etang

    Full Text Available BACKGROUND: From 2006 to 2011, biological activity of insecticides for Indoor Residual Spraying (IRS, conventional treatment of nets (CTNs or long lasting insecticidal nets (LLINs was evaluated before their approval in Cameroon. The objective of the study was to select the best tools for universal malaria vector control coverage. METHODOLOGY: Bioassays were performed using WHO cones and the Kisumu susceptible strain of Anopheles gambiae s.s.. Among tested products, residual activity and wash resistance of Alpha-cypermethrin LLINs (Interceptor and CTNs (Fendona were assessed during 5 months in the Ntougou neighborhood. PRINCIPAL FINDINGS: All the 14 tested products were found effective (95-100% knockdown and mortality rates, although a significant decrease of efficacy was seen with lambda-cyhalothrinWP IRS, alpha-cypermethrin CTNs and LLINs (p< 0.05. However, the efficacy of Interceptor nets did not decrease during the 5 months evaluation, even after 25 washes (0.07Cameroon.

  15. Nephelometric Dropsonde for Volcanic Ash Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced dropsondes that could effectively be guided through atmospheric regions of interest such as volcanic plumes could enable unprecedented observations of...

  16. Catastrophic volcanic collapse: relation to hydrothermal processes.

    Science.gov (United States)

    López, D L; Williams, S N

    1993-06-18

    Catastrophic volcanic collapse, without precursory magmatic activity, is characteristic of many volcanic disasters. The extent and locations of hydrothermal discharges at Nevado del Ruiz volcano, Colombia, suggest that at many volcanoes collapse may result from the interactions between hydrothermal fluids and the volcanic edifice. Rock dissolution and hydrothermal mineral alteration, combined with physical triggers such as earth-quakes, can produce volcanic collapse. Hot spring water compositions, residence times, and flow paths through faults were used to model potential collapse at Ruiz. Caldera dimensions, deposits, and alteration mineral volumes are consistent with parameters observed at other volcanoes.

  17. Cholera public health surveillance in the Republic of Cameroon-opportunities and challenges

    Science.gov (United States)

    Ngwa, Moise Chi; Liang, Song; Mbam, Leonard Mbam; Mouhaman, Arabi; Teboh, Andrew; Brekmo, Kaousseri; Mevoula, Onana; Morris, John Glenn

    2016-01-01

    Introduction In Cameroon, cholera has periodically resurfaced since it was first reported in 1971. In 2003, Cameroon adapted the Integrated Disease Surveillance and Response (IDSR) strategy to strengthen surveillance in the country. This study was an in-depth description and assessment of the structure, core and support functions, and attributes of the current cholera surveillance system in Cameroon. It also discussed its strengths and challenges with hope that lessons learned could improve the system in Cameroon and in other countries in Africa implementing the IDSR strategy. Methods Semi-structured key informant interviews, peer reviewed articles, and government record review were conducted in the Far North and Centre Regions of Cameroon. We used the matrix and conceptual framework from the World Health Organization (WHO) and Centers for Disease Control and Prevention, WHO Regional Office for Africa Technical Guidelines to frame the study. Site visits included the WHO country office, the ministry of public health (MoPH), two Regional Public Health Delegations (RPHDs), eight health districts (HDs) and health facilities (HFs) including two labs. Results Cholera surveillance is passive but turns active during outbreaks and follows a hierarchical structure. Cholera data are collected at HFs and sent to HDs where data are compiled and sent to the RPHD in paper format. RPHDs de-identify, digitalize, and send the data to the MoPH via internet and from there to the WHO. The case definition was officially changed in 2010 but the outdated definition was still in use in 2013. Nationally, there are 3 laboratories that have the ability to confirm cholera cases; the lack of laboratory capacity at HFs hampers case and outbreak confirmation. The absence of structured data analysis at the RPHD, HD, and HF further compounds the situation, making the goal of IDSR of data analysis and rapid response at the HD very challenging. Feedback is strongest at the central level (MoPH) and

  18. Detection of a new subgenotype of hepatitis B virus genotype A in Cameroon but not in neighbouring Nigeria.

    Science.gov (United States)

    Hübschen, J M; Mbah, P O; Forbi, J C; Otegbayo, J A; Olinger, C M; Charpentier, E; Muller, C P

    2011-01-01

    To further investigate the genetic diversity of hepatitis B virus (HBV) genotype A in Africa, we analysed 263 HBV strains from Nigeria (n=163) and Cameroon (n=100). Phylogenetic analysis of S fragment sequences attributed 175 strains (66.5%) to genotype E and 88 (33.5%) to genotype A. In Cameroon, genotype A strains were the most prevalent (79/100, 79.0%), whereas, in Nigeria, genotype E was highly dominant (154/163, 94.5%). The genotype A strains grouped with reference strains of subgenotype A3 (n=8), the provisional subgenotype A5 (n=43), a recently reported new variant from Rwanda (n=35), or as outliers (n=2). Ten complete genome sequences obtained from strains that clustered with the new variant from Rwanda formed a separate group supported by a bootstrap value of 96. The between-group distance to other potential or recognized subgenotypes of genotype A was at least 3.81%. Thus, the new group of strains could be considered as a new subgenotype of HBV genotype A, tentatively named 'A7'. Interestingly, the 'A7' strains from Rwanda and Cameroon showed an interspersed clustering, but essentially no other (sub)genotypes were shared between the two countries, suggesting that 'A7' may have evolved in a yet unknown place and may have only relatively recently spread to Rwanda and Western Cameroon. Strains attributed to provisional subgenotype A5 were found for the first time in Cameroon (n=36) and Central Nigeria (n=2), indicating that A5 is more widespread than previously thought.

  19. Thermal vesiculation during volcanic eruptions

    Science.gov (United States)

    Lavallée, Yan; Dingwell, Donald B.; Johnson, Jeffrey B.; Cimarelli, Corrado; Hornby, Adrian J.; Kendrick, Jackie E.; von Aulock, Felix W.; Kennedy, Ben M.; Andrews, Benjamin J.; Wadsworth, Fabian B.; Rhodes, Emma; Chigna, Gustavo

    2015-12-01

    Terrestrial volcanic eruptions are the consequence of magmas ascending to the surface of the Earth. This ascent is driven by buoyancy forces, which are enhanced by bubble nucleation and growth (vesiculation) that reduce the density of magma. The development of vesicularity also greatly reduces the ‘strength’ of magma, a material parameter controlling fragmentation and thus the explosive potential of the liquid rock. The development of vesicularity in magmas has until now been viewed (both thermodynamically and kinetically) in terms of the pressure dependence of the solubility of water in the magma, and its role in driving gas saturation, exsolution and expansion during decompression. In contrast, the possible effects of the well documented negative temperature dependence of solubility of water in magma has largely been ignored. Recently, petrological constraints have demonstrated that considerable heating of magma may indeed be a common result of the latent heat of crystallization as well as viscous and frictional heating in areas of strain localization. Here we present field and experimental observations of magma vesiculation and fragmentation resulting from heating (rather than decompression). Textural analysis of volcanic ash from Santiaguito volcano in Guatemala reveals the presence of chemically heterogeneous filaments hosting micrometre-scale vesicles. The textures mirror those developed by disequilibrium melting induced via rapid heating during fault friction experiments, demonstrating that friction can generate sufficient heat to induce melting and vesiculation of hydrated silicic magma. Consideration of the experimentally determined temperature and pressure dependence of water solubility in magma reveals that, for many ascent paths, exsolution may be more efficiently achieved by heating than by decompression. We conclude that the thermal path experienced by magma during ascent strongly controls degassing, vesiculation, magma strength and the effusive

  20. Water in volcanic glass: From volcanic degassing to secondary hydration

    Science.gov (United States)

    Seligman, Angela N.; Bindeman, Ilya N.; Watkins, James M.; Ross, Abigail M.

    2016-10-01

    Volcanic glass is deposited with trace amounts (0.1-0.6 wt.%) of undegassed magmatic water dissolved in the glass. After deposition, meteoric water penetrates into the glass structure mostly as molecular H2O. Due to the lower δD (‰) values of non-tropical meteoric waters and the ∼30‰ offset between volcanic glass and environmental water during hydration, secondary water imparts lighter hydrogen isotopic values during secondary hydration up to a saturation concentration of 3-4 wt.% H2O. We analyzed compositionally and globally diverse volcanic glass from 0 to 10 ka for their δD and H2Ot across different climatic zones, and thus different δD of precipitation, on a thermal conversion elemental analyzer (TCEA) furnace attached to a mass spectrometer. We find that tephrachronologically coeval rhyolite glass is hydrated faster than basaltic glass, and in the majority of glasses an increase in age and total water content leads to a decrease in δD (‰), while a few equatorial glasses have little change in δD (‰). We compute a magmatic water correction based on our non-hydrated glasses, and calculate an average 103lnαglass-water for our hydrated felsic glasses of -33‰, which is similar to the 103lnαglass-water determined by Friedman et al. (1993a) of -34‰. We also determine a smaller average 103lnαglass-water for all our mafic glasses of -23‰. We compare the δD values of water extracted from our glasses to local meteoric waters following the inclusion of a -33‰ 103lnαglass-water. We find that, following a correction for residual magmatic water based on an average δD and wt.% H2Ot of recently erupted ashes from our study, the δD value of water extracted from hydrated volcanic glass is, on average, within 4‰ of local meteoric water. To better understand the difference in hydration rates of mafic and felsic glasses, we imaged 6 tephra clasts ranging in age and chemical composition with BSE (by FEI SEM) down to a submicron resolution. Mafic tephra

  1. Geochemical Characteristics and Metallogenesis of Volcanic Rocks as Exemplified by Volcanic Rocks in Ertix,Xinjiang

    Institute of Scientific and Technical Information of China (English)

    刘铁庚; 叶霖

    1997-01-01

    Volcanic rocks in Ertix,Xinjiang,occurring in the collision zone between the Siberia Plate and the Junggar Plate,are distributed along the Eritix River Valley in northern Xinjiang.The volcanic rocks were dated at Late Paleozoic and can be divided into the spilite-keratophyre series and the basalt-andesite series.The spilite-keratophyre series volcanic rocks occur in the Altay orogenic belt at the southwest margin of the Siberia Plate.In addition to sodic volcanic rocks.There are also associated potassic-sodic volcanic rocks and potassic volcanic rocks.The potassic-sodic volcanic rocks occur at the bottom of the eruption cycle and control the distribution of Pb and Zn deposits.The potassic volcanic rocks occur at the top of the eruption cycle and are associated with Au and Cu mineralizations.The sodic volcanic rocks occur in the middle stage of eruption cycle and control the occurrence of Cu(Zn) deposits.The basalt-andesite series volcanic rocks distributed in the North Junggar orogenic belt at the north margin of the Junggar-Kazakstan Plate belong to the potassic sodic volcain rocks.The volcanic rocks distributed along the Ulungur fault are relatively rich in sodium and poor in potassium and are predominated by Cu mineralization and associated with Au mineralization.Those volcanic rocks distributed along the Ertix fault are relatively rich in K and poor in Na,with Au mineralization being dominant.

  2. Report of the 7th international workshop on colposcopy, screening and prevention of cervical cancer, Douala, Cameroon, March 30 - 31 and April 1st 2016

    Directory of Open Access Journals (Sweden)

    Jovanny Tsuala Fouogue

    2016-09-01

    Conclusions: Master's classes, free communications and discussions were fruitful and appointment was taken for March 30-31, 2017 in Yaounde, Cameroon. [Int J Reprod Contracept Obstet Gynecol 2016; 5(9.000: 3269-3274

  3. Characterization of Bacillus anthracis-Like Bacteria Isolated from Wild Great Apes from Côte d'Ivoire and Cameroon

    OpenAIRE

    Klee, Silke R.; Özel, Muhsin; Appel, Bernd; Boesch, Christophe; Ellerbrok, Heinz; Jacob, Daniela; Holland, Gudrun; Fabian H Leendertz; Pauli, Georg; Grunow, Roland; Nattermann, Herbert

    2006-01-01

    We present the microbiological and molecular characterization of bacteria isolated from four chimpanzees and one gorilla thought to have died of an anthrax-like disease in Côte d'Ivoire and Cameroon. These isolates differed significantly from classic Bacillus anthracis by the following criteria: motility, resistance to the gamma phage, and, for isolates from Cameroon, resistance to penicillin G. A capsule was expressed not only after induction by CO2 and bicarbonate but also under normal grow...

  4. Volcanic Rocks As Targets For Astrobiology Missions

    Science.gov (United States)

    Banerjee, N.

    2010-12-01

    Almost two decades of study highlight the importance of terrestrial subaqueous volcanic rocks as microbial habitats, particularly in glass produced by the quenching of basaltic lava upon contact with water. On Earth, microbes rapidly begin colonizing glassy surfaces along fractures and cracks exposed to water. Microbial colonization of basaltic glass leads to enhanced alteration through production of characteristic granular and/or tubular bioalteration textures. Infilling of formerly hollow alteration textures by minerals enable their preservation through geologic time. Basaltic rocks are a major component of the Martian crust and are widespread on other solar system bodies. A variety of lines of evidence strongly suggest the long-term existence of abundant liquid water on ancient Mars. Recent orbiter, lander and rover missions have found evidence for the presence of transient liquid water on Mars, perhaps persisting to the present day. Many other solar system bodies, notably Europa, Enceladus and other icy satellites, may contain (or have once hosted) subaqueous basaltic glasses. The record of terrestrial glass bioalteration has been interpreted to extend back ~3.5 billion years and is widespread in modern oceanic crust and its ancient metamorphic equivalents. The terrestrial record of glass bioalteration strongly suggests that glassy or formerly glassy basaltic rocks on extraterrestrial bodies that have interacted with liquid water are high-value targets for astrobiological exploration.

  5. Engineering a robotic approach to mapping exposed volcanic fissures

    Science.gov (United States)

    Parcheta, C. E.; Parness, A.; Mitchell, K. L.

    2014-12-01

    Field geology provides a framework for advanced computer models and theoretical calculations of volcanic systems. Some field terrains, though, are poorly preserved or accessible, making documentation, quantification, and investigation impossible. Over 200 volcanologists at the 2012 Kona Chapman Conference on volcanology agreed that and important step forward in the field over the next 100 years should address the realistic size and shape of volcanic conduits. The 1969 Mauna Ulu eruption of Kīlauea provides a unique opportunity to document volcanic fissure conduits, thus, we have an ideal location to begin addressing this topic and provide data on these geometries. Exposed fissures can be mapped with robotics using machine vision. In order to test the hypothesis that fissures have irregularities with depth that will influence their fluid dynamical behavior, we must first map the fissure vents and shallow conduit to deci- or centimeter scale. We have designed, constructed, and field-tested the first version of a robotic device that will image an exposed volcanic fissure in three dimensions. The design phase included three steps: 1) create the payload harness and protective shell to prevent damage to the electronics and robot, 2) construct a circuit board to have the electronics communicate with a surface-based computer, and 3) prototype wheel shapes that can handle a variety of volcanic rock textures. The robot's mechanical parts were built using 3d printing, milling, casting and laser cutting techniques, and the electronics were assembled from off the shelf components. The testing phase took place at Mauna Ulu, Kīlauea, Hawai'i, from May 5 - 9, 2014. Many valuable design lessons were learned during the week, and the first ever 3D map from inside a volcanic fissure were successfully collected. Three vents had between 25% and 95% of their internal surfaces imaged. A fourth location, a non-eruptive crack (possibly a fault line) had two transects imaging the textures

  6. Geosphere-Biosphere Interactions in Bio-Activity Volcanic Lakes: Evidences from Hule and Rìo Cuarto (Costa Rica)

    Science.gov (United States)

    Cabassi, Jacopo; Tassi, Franco; Mapelli, Francesca; Borin, Sara; Calabrese, Sergio; Rouwet, Dmitri; Chiodini, Giovanni; Marasco, Ramona; Chouaia, Bessem; Avino, Rosario; Vaselli, Orlando; Pecoraino, Giovannella; Capecchiacci, Francesco; Bicocchi, Gabriele; Caliro, Stefano; Ramirez, Carlos; Mora-Amador, Raul

    2014-01-01

    Hule and Río Cuarto are maar lakes located 11 and 18 km N of Poás volcano along a 27 km long fracture zone, in the Central Volcanic Range of Costa Rica. Both lakes are characterized by a stable thermic and chemical stratification and recently they were affected by fish killing events likely related to the uprising of deep anoxic waters to the surface caused by rollover phenomena. The vertical profiles of temperature, pH, redox potential, chemical and isotopic compositions of water and dissolved gases, as well as prokaryotic diversity estimated by DNA fingerprinting and massive 16S rRNA pyrosequencing along the water column of the two lakes, have highlighted that different bio-geochemical processes occur in these meromictic lakes. Although the two lakes host different bacterial and archaeal phylogenetic groups, water and gas chemistry in both lakes is controlled by the same prokaryotic functions, especially regarding the CO2-CH4 cycle. Addition of hydrothermal CO2 through the bottom of the lakes plays a fundamental priming role in developing a stable water stratification and fuelling anoxic bacterial and archaeal populations. Methanogens and methane oxidizers as well as autotrophic and heterotrophic aerobic bacteria responsible of organic carbon recycling resulted to be stratified with depth and strictly related to the chemical-physical conditions and availability of free oxygen, affecting both the CO2 and CH4 chemical concentrations and their isotopic compositions along the water column. Hule and Río Cuarto lakes were demonstrated to contain a CO2 (CH4, N2)-rich gas reservoir mainly controlled by the interactions occurring between geosphere and biosphere. Thus, we introduced the term of bio-activity volcanic lakes to distinguish these lakes, which have analogues worldwide (e.g. Kivu: D.R.C.-Rwanda; Albano, Monticchio and Averno: Italy; Pavin: France) from volcanic lakes only characterized by geogenic CO2 reservoir such as Nyos and Monoun (Cameroon). PMID

  7. Geosphere-biosphere interactions in bio-activity volcanic lakes: evidences from Hule and Rio Cuarto (Costa Rica.

    Directory of Open Access Journals (Sweden)

    Jacopo Cabassi

    Full Text Available Hule and Río Cuarto are maar lakes located 11 and 18 km N of Poás volcano along a 27 km long fracture zone, in the Central Volcanic Range of Costa Rica. Both lakes are characterized by a stable thermic and chemical stratification and recently they were affected by fish killing events likely related to the uprising of deep anoxic waters to the surface caused by rollover phenomena. The vertical profiles of temperature, pH, redox potential, chemical and isotopic compositions of water and dissolved gases, as well as prokaryotic diversity estimated by DNA fingerprinting and massive 16S rRNA pyrosequencing along the water column of the two lakes, have highlighted that different bio-geochemical processes occur in these meromictic lakes. Although the two lakes host different bacterial and archaeal phylogenetic groups, water and gas chemistry in both lakes is controlled by the same prokaryotic functions, especially regarding the CO2-CH4 cycle. Addition of hydrothermal CO2 through the bottom of the lakes plays a fundamental priming role in developing a stable water stratification and fuelling anoxic bacterial and archaeal populations. Methanogens and methane oxidizers as well as autotrophic and heterotrophic aerobic bacteria responsible of organic carbon recycling resulted to be stratified with depth and strictly related to the chemical-physical conditions and availability of free oxygen, affecting both the CO2 and CH4 chemical concentrations and their isotopic compositions along the water column. Hule and Río Cuarto lakes were demonstrated to contain a CO2 (CH4, N2-rich gas reservoir mainly controlled by the interactions occurring between geosphere and biosphere. Thus, we introduced the term of bio-activity volcanic lakes to distinguish these lakes, which have analogues worldwide (e.g. Kivu: D.R.C.-Rwanda; Albano, Monticchio and Averno: Italy; Pavin: France from volcanic lakes only characterized by geogenic CO2 reservoir such as Nyos and Monoun

  8. Geosphere-biosphere interactions in bio-activity volcanic lakes: evidences from Hule and Rìo Cuarto (Costa Rica).

    Science.gov (United States)

    Cabassi, Jacopo; Tassi, Franco; Mapelli, Francesca; Borin, Sara; Calabrese, Sergio; Rouwet, Dmitri; Chiodini, Giovanni; Marasco, Ramona; Chouaia, Bessem; Avino, Rosario; Vaselli, Orlando; Pecoraino, Giovannella; Capecchiacci, Francesco; Bicocchi, Gabriele; Caliro, Stefano; Ramirez, Carlos; Mora-Amador, Raul

    2014-01-01

    Hule and Río Cuarto are maar lakes located 11 and 18 km N of Poás volcano along a 27 km long fracture zone, in the Central Volcanic Range of Costa Rica. Both lakes are characterized by a stable thermic and chemical stratification and recently they were affected by fish killing events likely related to the uprising of deep anoxic waters to the surface caused by rollover phenomena. The vertical profiles of temperature, pH, redox potential, chemical and isotopic compositions of water and dissolved gases, as well as prokaryotic diversity estimated by DNA fingerprinting and massive 16S rRNA pyrosequencing along the water column of the two lakes, have highlighted that different bio-geochemical processes occur in these meromictic lakes. Although the two lakes host different bacterial and archaeal phylogenetic groups, water and gas chemistry in both lakes is controlled by the same prokaryotic functions, especially regarding the CO2-CH4 cycle. Addition of hydrothermal CO2 through the bottom of the lakes plays a fundamental priming role in developing a stable water stratification and fuelling anoxic bacterial and archaeal populations. Methanogens and methane oxidizers as well as autotrophic and heterotrophic aerobic bacteria responsible of organic carbon recycling resulted to be stratified with depth and strictly related to the chemical-physical conditions and availability of free oxygen, affecting both the CO2 and CH4 chemical concentrations and their isotopic compositions along the water column. Hule and Río Cuarto lakes were demonstrated to contain a CO2 (CH4, N2)-rich gas reservoir mainly controlled by the interactions occurring between geosphere and biosphere. Thus, we introduced the term of bio-activity volcanic lakes to distinguish these lakes, which have analogues worldwide (e.g. Kivu: D.R.C.-Rwanda; Albano, Monticchio and Averno: Italy; Pavin: France) from volcanic lakes only characterized by geogenic CO2 reservoir such as Nyos and Monoun (Cameroon).

  9. Molecular monitoring of plasmodium falciparum drug susceptibility at the time of the introduction of artemisinin-based combination therapy in Yaoundé, Cameroon: Implications for the future

    Directory of Open Access Journals (Sweden)

    Menard Sandie

    2012-04-01

    Full Text Available Abstract Background Regular monitoring of the levels of anti-malarial resistance of Plasmodium falciparum is an essential policy to adapt therapy and improve malaria control. This monitoring can be facilitated by using molecular tools, which are easier to implement than the classical determination of the resistance phenotype. In Cameroon, chloroquine (CQ, previously the first-line therapy for uncomplicated malaria was officially withdrawn in 2002 and replaced initially by amodiaquine (AQ monotherapy. Then, artemisinin-based combination therapy (ACT, notably artesunate-amodiaquine (AS-AQ or artemether-lumefantrine (AL, was gradually introduced in 2004. This situation raised the question of the evolution of P. falciparum resistance molecular markers in Yaoundé, a highly urbanized Cameroonian city. Methods The genotype of pfcrt 72 and 76 and pfmdr1 86 alleles and pfmdr1 copy number were determined using real-time PCR in 447 P. falciparum samples collected between 2005 and 2009. Results This study showed a high prevalence of parasites with mutant pfcrt 76 (83% and pfmdr1 86 (93% codons. On the contrary, no mutations in the pfcrt 72 codon and no samples with duplication of the pfmdr1 gene were observed. Conclusion The high prevalence of mutant pfcrt 76T and pfmdr1 86Y alleles might be due to the choice of alternative drugs (AQ and AS-AQ known to select such genotypes. Mutant pfcrt 72 codon was not detected despite the prolonged use of AQ either as monotherapy or combined with artesunate. The absence of pfmdr1 multicopies suggests that AL would still remain efficient. The limited use of mefloquine or the predominance of mutant pfmdr1 86Y codon could explain the lack of pfmdr1 amplification. Indeed, this mutant codon is rarely associated with duplication of pfmdr1 gene. In Cameroon, the changes of therapeutic strategies and the simultaneous use of several formulations of ACT or other anti-malarials that are not officially recommended result in a

  10. Cenozoic volcanic rocks of Saudi Arabia

    Science.gov (United States)

    Coleman, R.G.; Gregory, R.T.; Brown, G.F.

    2016-01-01

    The Cenozoic volcanic rocks of Saudi Arabia cover about 90,000 km2, one of the largest areas of alkali olivine basalt in the world. These volcanic rocks are in 13 separate fields near the eastern coast of the Red Sea and in the western Arabian Peninsula highlands from Syria southward to the Yemen Arab Republic.

  11. Relationship between earthquake and volcanic eruption inferred from historical records

    Institute of Scientific and Technical Information of China (English)

    陈洪洲; 高峰; 吴雪娟; 孟宪森

    2004-01-01

    A large number of seismic records are discovered for the first time in the historical materials about Wudalianchi volcanic group eruption in 1720~1721, which provides us with abundant volcanic earthquake information. Based on the written records, the relationship between earthquake and volcanic eruption is discussed in the paper. Furthermore it is pointed that earthquake swarm is an important indication of volcanic eruption. Therefore, monitoring volcanic earthquakes is of great significance for forecasting volcanic eruption.

  12. Are students kidding with health research ethics? The case of HIV/AIDS research in Cameroon

    Science.gov (United States)

    2012-01-01

    Background Universities in Cameroon are playing an active part in HIV/AIDS research and much of this research is carried out by students, usually for the purpose of a dissertation/thesis. Student theses/dissertations present research findings in a much more comprehensive manner and have been described as the stepping-stone of a budding scientist’s potential in becoming an independent researcher. It is therefore important to verify how students handle issues of research ethics. Method Theses/dissertations on HIV/AIDS that described research studies involving the use of human research participants were screened to verify if research ethics approval and informed consent were obtained and documented. The contents of the consent forms were also qualitatively analyzed. Results Of 174 theses/dissertations on HIV, ethics approval was documented in 17 (9.77%) and informed consent in 77 (47.83%). Research ethics approval was first mentioned at all in 2002 and highly reported in the year 2007. Evidence of ethics approval was found for the first time in 2005 and informed consent first observed and evidenced in 1997. Ethics approval was mostly reported by students studying for an MD (14.01%) and was not reported in any Bachelors’ degree dissertation. Informed consent was also highly reported in MD theses (64.58%) followed by undergraduate theses (31.58%). Voluntary participation and potential benefits of the study were some of the common aspects dealt with in most of the consent forms. The right to discontinue participation in the study and management of residual samples were scarcely ever mentioned. Conclusions Overall, and given the current state of the art of research ethics around the world, student-scientists in Cameroon would seem to be merely kidding with research ethics. It is thus essential that training in health research ethics (HRE) be incorporated in the curriculum of universities in Cameroon in order that the next generation of scientists may be better

  13. [Experiences of Cameroon in population planning and economic and social development].

    Science.gov (United States)

    Kossivi Ayassou, M V

    1987-12-01

    Because it already has over 30 years of experience in preparing and executing 5-year plans, Cameroon was chosen as the case study for a workshop on training of African planners in population, human resources, and development planning. This communication, based on analysis of the 1st 5 plans and preparatory documents for the 6th, is divided into 4 chapters. The 1st chapter studies the methodology and structures for plan development and the models used in projections and forecasts. The 2nd chapter discusses sectorial programs while the 3rd examines the place of population in the different plans. The final chapter proposes a practical approach to planning of population, human resources, and development in Africa. Cameroon's experience in planning is instructive because it shows the growing consciousness of the importance of population factors and the progressive integration of demographic variables in the plans. The 20-year process began with construction of planning structures at the central, regional, and provincial levels, followed by constitution of series of demographic data and finally the establishment of a population commission that defined the major outlines of Cameroon's population policy and its translation into national, regional, and sectorial development plans. The results obtained were evidence of the political will of high authorities and of the technical competence of planning staffs. The framework for planning of population, human resources, and development in Africa is intended to guide planners while being adaptable to the conditions, structures, and needs of each particular country. The 9-step framework begins with an inventory and evaluation of statistical data available for planning, followed by definitions of the overall orientation of national development and of sectorial, regional, and national objectives of the plan. The 4th step is a study of the interdependence between population and social and economic factors, followed by development of

  14. Origin and paleoenvironment of Pleistocene-Holocene Travertine deposit from the Mbéré sedimentary sub-basin along the Central Cameroon shear zone: Insights from petrology and palynology and evidence for neotectonics

    Science.gov (United States)

    Tchouatcha, Milan Stafford; Njoya, André; Ganno, Sylvestre; Toyama, Réné; Ngouem, Paul Aubin; Njiké Ngaha, Pierre Ricard

    2016-06-01

    The Mbéré sub-basin belongs to the Mbéré-Djerem intra-continental basin of Central North Cameroon. In this sub-basin, a travertine outcrop has been discovered and investigated palynologically and petrologically in this study. The sporopollinic content of the studied travertine is mainly composed of fungal spores (Rhyzophagites sp., Monoporisporites sp …) associated with rare fresh water algae spores such as Chomotriletes minor and angiosperm pollens (compositae, graminae, …). This sporopollinic association is indicative of hot and semi-arid to arid paleoclimate and reveals a Pleistocene-Holocene depositional age. The whole rock major element geochemistry shows relative enrichment of CaO (49.48%) and CO2 (38.49%). The origin of CO2 is probably from magmatic and/or metamorphic fluids. Compared to other travertines, SiO2 and Al2O3 contents are significant with average concentrations of 5.68% and 2.58% respectively. The mineralogical composition revealed by a microscopic study of bulk rocks is dominated by calcite (90-92%) associated to quartz (2-4%) and feldspar (2-3%), meanwhile the heavy mineral concentrate is formed by various mineral types such as zircon (most abundant), garnet, tourmaline, epidote, biotite, peridot and aegirine augite suggesting that the underground water has crossed both volcanic, plutonic and metamorphic rocks. With the mineral composition made of both chemical and detrital derived elements, the Mbéré travertine corresponds to chemico-lithoclastic/detrital limestone. In the Mbéré trough, numerous thermo-mineral springs are located along major fractures and faults. This result suggests that the Mbéré travertine deposit is related to the rising of deep water with the help of a fracturing system, similar to those of Irdi (Morocco), Italy and Turkey where there is much volcanism.

  15. Geomorphological Approach for Regional Zoning In The Merapi Volcanic Area

    Directory of Open Access Journals (Sweden)

    Langgeng Wahyu Santosa

    2013-07-01

    Full Text Available Geomorphologial approach can be used as the basic for identifying and analyzing the natural resources potentials, especially in volcanic landscape. Based on its geomorphology, Merapi volcanic landscape can be divided into 5 morphological units, i.e.: volcanic cone, volcanic slope, volcanic foot, volcanic foot plain, and fluvio-volcanic plain. Each of these morphological units has specific characteristic and natural resources potential. Based on the condition of geomorphology, the regional zoning can be compiled to support the land use planning and to maintain the conservation of environmental function in the Merapi Volcanic area.

  16. Volcanism and associated hazards: the Andean perspective

    Science.gov (United States)

    Tilling, R. I.

    2009-12-01

    Andean volcanism occurs within the Andean Volcanic Arc (AVA), which is the product of subduction of the Nazca Plate and Antarctica Plates beneath the South America Plate. The AVA is Earth's longest but discontinuous continental-margin volcanic arc, which consists of four distinct segments: Northern Volcanic Zone, Central Volcanic Zone, Southern Volcanic Zone, and Austral Volcanic Zone. These segments are separated by volcanically inactive gaps that are inferred to indicate regions where the dips of the subducting plates are too shallow to favor the magma generation needed to sustain volcanism. The Andes host more volcanoes that have been active during the Holocene (past 10 000 years) than any other volcanic region in the world, as well as giant caldera systems that have produced 6 of the 47 largest explosive eruptions (so-called "super eruptions") recognized worldwide that have occurred from the Ordovician to the Pleistocene. The Andean region's most powerful historical explosive eruption occurred in 1600 at Huaynaputina Volcano (Peru). The impacts of this event, whose eruptive volume exceeded 11 km3, were widespread, with distal ashfall reported at distances >1000 km away. Despite the huge size of the Huaynaputina eruption, human fatalities from hazardous processes (pyroclastic flows, ashfalls, volcanogenic earthquakes, and lahars) were comparatively small owing to the low population density at the time. In contrast, lahars generated by a much smaller eruption (indecisiveness by government officials, rather than any major deficiencies in scientific data. Ruiz's disastrous outcome, however, together with responses to subsequent hazardous eruptions in Chile, Colombia, Ecuador, and Peru has spurred significant improvements in reducing volcano risk in the Andean region. But much remains to be done.

  17. Volcanism and associated hazards: The Andean perspective

    Science.gov (United States)

    Tilling, R.I.

    2009-01-01

    Andean volcanism occurs within the Andean Volcanic Arc (AVA), which is the product of subduction of the Nazca Plate and Antarctica Plates beneath the South America Plate. The AVA is Earth's longest but discontinuous continental-margin volcanic arc, which consists of four distinct segments: Northern Volcanic Zone, Central Volcanic Zone, Southern Volcanic Zone, and Austral Volcanic Zone. These segments are separated by volcanically inactive gaps that are inferred to indicate regions where the dips of the subducting plates are too shallow to favor the magma generation needed to sustain volcanism. The Andes host more volcanoes that have been active during the Holocene (past 10 000 years) than any other volcanic region in the world, as well as giant caldera systems that have produced 6 of the 47 largest explosive eruptions (so-called "super eruptions") recognized worldwide that have occurred from the Ordovician to the Pleistocene. The Andean region's most powerful historical explosive eruption occurred in 1600 at Huaynaputina Volcano (Peru). The impacts of this event, whose eruptive volume exceeded 11 km3, were widespread, with distal ashfall reported at distances >1000 km away. Despite the huge size of the Huaynaputina eruption, human fatalities from hazardous processes (pyroclastic flows, ashfalls, volcanogenic earthquakes, and lahars) were comparatively small owing to the low population density at the time. In contrast, lahars generated by a much smaller eruption (indecisiveness by government officials, rather than any major deficiencies in scientific data. Ruiz's disastrous outcome, however, together with responses to subsequent hazardous eruptions in Chile, Colombia, Ecuador, and Peru has spurred significant improvements in reducing volcano risk in the Andean region. But much remains to be done.

  18. Measuring Disability in Population Based Surveys: The Interrelationship between Clinical Impairments and Reported Functional Limitations in Cameroon and India

    Science.gov (United States)

    2016-01-01

    Purpose To investigate the relationship between two distinct measures of disability: self-reported functional limitations and objectively-screened clinical impairments. Methods We undertook an all age population-based survey of disability in two areas: North-West Cameroon (August/October 2013) and Telangana State, India (Feb/April 2014). Participants were selected for inclusion via two-stage cluster randomised sampling (probability proportionate to size cluster selection and compact segment sampling within clusters). Disability was defined as the presence of self-reported functional limitations across eight domains, or presence of moderate or greater clinical impairments. Clinical impairment screening comprised of visual acuity testing for vision impairment, pure tone audiometry for hearing impairment, musculoskeletal functioning assessment for musculoskeletal impairment, reported seizure history for epilepsy and reported symptoms of clinical depression (depression adults only). Information was collected using structured questionnaires, observations and examinations. Results Self-reported disability prevalence was 5.9% (95% CI 4.7–7.4) and 7.5% (5.9–9.4) in Cameroon and India respectively. The prevalence of moderate or greater clinical impairments in the same populations were 8.4% (7.5–9.4) in Cameroon and 10.5% (9.4–11.7) in India. Overall disability prevalence (self-report and/or screened positive to a moderate or greater clinical impairment) was 10.5% in Cameroon and 12.2% in India, with limited overlap between the sub-populations identified using the two types of tools. 33% of participants in Cameroon identified to have a disability, and 45% in India, both reported functional limitations and screened positive to objectively-screened impairments, whilst the remainder were identified via one or other tool only. A large proportion of people with moderate or severe clinical impairments did not self-report functional difficulties despite reporting

  19. Child labour in Yaoundé-Cameroon: Some lessons drawn from a survey on children

    Directory of Open Access Journals (Sweden)

    Simon A. Song Ntamack

    2005-12-01

    Full Text Available Although child labour is a phenomenon widely studied around the world, there are few papers that tackle the problem in Cameroon. The objective of this paper is to fill the gap by questioning the subject in Yaoundé, the capital city. But child labour phenomenon is analysed here from a questionnaire that has two distinctive features: (i the questionnaire is exclusively devoted to child labour, and (ii all the participants in the survey are exclusively children themselves. No adult (parent, guardian, elder, employer, etc. was consulted and given a chance to answer on behalf of a child. This process is extremely rare in child labour, since in general individuals other than children are requested to testify and answer inslead of children. While some results obtained from a standard Logit model on the determinant of child labour are well known, the others are either not known or insignificant. We suspect that the reason is the data collection.

  20. Survey of the mineral status of pastures and small ruminants in the West Region of Cameroon

    Directory of Open Access Journals (Sweden)

    Njwe, RM.

    1988-01-01

    Full Text Available Four dominant grass species (Hyparrhenia rufa, Melinis minutiflora, Pennisetum purpureum and Sporobolus africanus of natural pastures of the West Region of Cameroon were sampled at 60 sites between September and November of 1985. The grass samples were analysed for calcium, phosphorus, potassium, magnesium, sodium, iron, mangenese, copper and zinc. Serum was also collected from goats and sheep at the same locations where forages were sampled and analysed for calcium, phosphorus, magnesium, zinc and copper. Results showed that P, Mg, A/a, Zn and Cu in forages were generally below the critical level stipulated to satisfy the requirements of grazing livestock in the tropics. Calcium was inadequate in the sera of goats and sheep where as P, Mg, Zn and Cu were adequate. Use of salt licks to supplement intake of mineral elements from grasses by goats and sheep is necessary in the region.

  1. Ecological status and sources of anthropogenic contaminants in mangroves of the Wouri River Estuary (Cameroon)

    KAUST Repository

    Fusi, Marco

    2016-07-07

    Mangroves are critically threatened by human activities, despite the important ecosystem functions and services they provide. Mangroves in Cameroon represent no exception to the worldwide trend of mangrove destruction, especially around Douala, on the Wouri river estuary. In two sites around Douala, we assessed the presence of sterols, PAHs, PCBs, DEHP, DDT and its metabolite p,p\\'-DDE and potentially toxic metals in sediment samples. As a proxy of ecological quality, we measured the diversity and abundance of macrobenthos assemblages. We detected p,p\\'-DDE contamination, with concentrations higher than 3μgkg-1 in 16 out of 26 samples which were attributed to recent widespread use of DDT. The detection of sterols revealed faecal contamination. Significant sensitivity of the macrobenthos to contaminants was revealed, with possible implications on the overall mangrove vulnerability to climate change and on the provision of ecosystem services to local populations. © 2016 Elsevier Ltd.

  2. Examination of the effects of public spending and trade policy on real exchange rate in Cameroon

    Directory of Open Access Journals (Sweden)

    Victalice Ngimanang ACHAMOH

    2015-11-01

    Full Text Available The study adopts the inter-temporal model of Rodríguez (1989 and Edward (1989 extended in Elbadawi and Soto (1997 to empirically examine the effect of public expenditure and trade openness on the real exchange rate using Cameroon data from 1977 to 2010. After exploring some issues on exchange rate and reviewing the relevant literature, the study employs residual based-cointegration technique. All the variables were stationary at level form or first differences. Public spending significantly appreciates the real exchange likewise the trade openness variable in the longrun. The results of the study suggests that appreciation of real exchange rate could be prevented by contracting public spending or adopting restrictive trade measures especially in the long run.

  3. Ecological status and sources of anthropogenic contaminants in mangroves of the Wouri River Estuary (Cameroon).

    Science.gov (United States)

    Fusi, Marco; Beone, Gian Maria; Suciu, Nicoleta Alina; Sacchi, Angela; Trevisan, Marco; Capri, Ettore; Daffonchio, Daniele; Din, Ndongo; Dahdouh-Guebas, Farid; Cannicci, Stefano

    2016-08-30

    Mangroves are critically threatened by human activities, despite the important ecosystem functions and services they provide. Mangroves in Cameroon represent no exception to the worldwide trend of mangrove destruction, especially around Douala, on the Wouri river estuary. In two sites around Douala, we assessed the presence of sterols, PAHs, PCBs, DEHP, DDT and its metabolite p,p'-DDE and potentially toxic metals in sediment samples. As a proxy of ecological quality, we measured the diversity and abundance of macrobenthos assemblages. We detected p,p'-DDE contamination, with concentrations higher than 3μgkg(-1) in 16 out of 26 samples which were attributed to recent widespread use of DDT. The detection of sterols revealed faecal contamination. Significant sensitivity of the macrobenthos to contaminants was revealed, with possible implications on the overall mangrove vulnerability to climate change and on the provision of ecosystem services to local populations.

  4. Aflatoxin Contamination in Food and Body Fluids in Relation to Malnutrition and Cancer Status in Cameroon

    Directory of Open Access Journals (Sweden)

    Félicité M. Tchouanguep

    2010-01-01

    Full Text Available Aflatoxins are food contaminants usually associated with hepatitis, immunodepression, impairment of fertility and cancer. The present work was to determine the presence of aflatoxins in eggs, milk, urine, and blood samples that were collected from various sources and periods; and hepatitis B virus antigen in blood samples. Aflatoxin was found in eggs (45.2%, cow raw milk (15.9%, breast milk (4.8%, urine from kwashiorkor and marasmic kwashiorkor children (45.5%, and sera from primary liver cancer patients (63.9%; HbsAg was also detected in 69.4% of the serum samples, but there was no association between both factors. Both AF and hepatitis B virus seem to be risk factors that could increase the incidence and prevalence rates of malnutrition and cancer in Cameroon.

  5. Complete genome sequence of a new bipartite begomovirus infecting fluted pumpkin (Telfairia occidentalis) plants in Cameroon.

    Science.gov (United States)

    Leke, Walter N; Khatabi, Behnam; Fondong, Vincent N; Brown, Judith K

    2016-08-01

    The complete genome sequence was determined and characterized for a previously unreported bipartite begomovirus from fluted pumpkin (Telfairia occidentalis, family Cucurbitaceae) plants displaying mosaic symptoms in Cameroon. The DNA-A and DNA-B components were ~2.7 kb and ~2.6 kb in size, and the arrangement of viral coding regions on the genomic components was like those characteristic of other known bipartite begomoviruses originating in the Old World. While the DNA-A component was more closely related to that of chayote yellow mosaic virus (ChaYMV), at 78 %, the DNA-B component was more closely related to that of soybean chlorotic blotch virus (SbCBV), at 64 %. This newly discovered bipartite Old World virus is herein named telfairia mosaic virus (TelMV).

  6. Mycorrhiza status of Gnetum spp. in Cameroon: evaluating diversity with a view to ameliorating domestication efforts.

    Science.gov (United States)

    Bechem, Eneke Esoeyang Tambe; Alexander, Ian James

    2012-02-01

    A field survey was carried out to investigate the diversity of mycorrhizal fungi associated with Gnetum spp. in Cameroon. The extent and variation of ectomycorrhizal colonisation as well as the degree of host specificity were evaluated. Gnetum spp. were found to be almost always ectomycorrhizal in all sites visited. There were just two ectomycorrhizal morphotypes ('yellow' and 'white') associated with this plant. Such low diversity is unusual for an ectomycorrhizal plant. The yellow morphotype was the most widespread and prevalent and was identified by morphological and molecular methods to have been formed with Scleroderma sinnamariense. Propagules of this fungus were present in soil collected from farm lands, cocoa plantations, Chromolaena and bush fallows, as well as in a relatively undisturbed forest harbouring ectomycorrhizal legumes. The fungus responsible for the white morphotype was identified as also belonging to the genus Scleroderma by ITS sequence similarity. Arbuscular mycorrhizal structures were absent in cleared and stained portions of the roots.

  7. Parameter estimation based synchronization for an epidemic model with application to tuberculosis in Cameroon

    Energy Technology Data Exchange (ETDEWEB)

    Bowong, Samuel, E-mail: sbowong@gmail.co [Laboratory of Applied Mathematics, Department of Mathematics and Computer Science, Faculty of Science, University of Douala, P.O. Box 24157 Douala (Cameroon); Postdam Institute for Climate Impact Research (PIK), Telegraphenberg A 31, 14412 Potsdam (Germany); Kurths, Jurgen [Postdam Institute for Climate Impact Research (PIK), Telegraphenberg A 31, 14412 Potsdam (Germany); Department of Physics, Humboldt Universitat zu Berlin, 12489 Berlin (Germany)

    2010-10-04

    We propose a method based on synchronization to identify the parameters and to estimate the underlying variables for an epidemic model from real data. We suggest an adaptive synchronization method based on observer approach with an effective guidance parameter to update rule design only from real data. In order, to validate the identifiability and estimation results, numerical simulations of a tuberculosis (TB) model using real data of the region of Center in Cameroon are performed to estimate the parameters and variables. This study shows that some tools of synchronization of nonlinear systems can help to deal with the parameter and state estimation problem in the field of epidemiology. We exploit the close link between mathematical modelling, structural identifiability analysis, synchronization, and parameter estimation to obtain biological insights into the system modelled.

  8. Parameter estimation based synchronization for an epidemic model with application to tuberculosis in Cameroon

    Science.gov (United States)

    Bowong, Samuel; Kurths, Jurgen

    2010-10-01

    We propose a method based on synchronization to identify the parameters and to estimate the underlying variables for an epidemic model from real data. We suggest an adaptive synchronization method based on observer approach with an effective guidance parameter to update rule design only from real data. In order, to validate the identifiability and estimation results, numerical simulations of a tuberculosis (TB) model using real data of the region of Center in Cameroon are performed to estimate the parameters and variables. This study shows that some tools of synchronization of nonlinear systems can help to deal with the parameter and state estimation problem in the field of epidemiology. We exploit the close link between mathematical modelling, structural identifiability analysis, synchronization, and parameter estimation to obtain biological insights into the system modelled.

  9. Endemic Burkitt Lymphoma: Long-term Outcome in 87 Patients Who Presented With Paraplegia in Cameroon.

    Science.gov (United States)

    Hesseling, P B; Mbah, G; Kouya, F; Kimbi, C; Nfor, P; Kaah, J; Kuruvilla, R; Best, A; Wharin, P

    2015-01-01

    The reported long-term outcome of endemic Burkitt lymphoma (eBL) patients who present with paraplegia is largely unknown. Records of BL patients treated with comparable short-interval cyclophosphamide chemotherapy schedules between 2004 and 2014 at three Baptist mission hospitals in Cameroon were reviewed. Survivors were followed up and examined at home or in hospital. Eighty-seven of 948 (9.2%) patients had paraplegia at diagnosis. The survival rate in eBL patients with paraplegia at diagnosis was 33% (n = 29) after follow-up of between 2 and 96 (median 40) months. Seven patients (24%) had neurological sequelae and needed rehabilitation. There was no relationship between the duration of symptoms (4 weeks) and the survival rate or the risk to have neurological sequelae. The survival rate and risk for sequelae were similar in patients with confirmed St. Jude stage III and IV diseases.

  10. Aflatoxin contamination in food and body fluids in relation to malnutrition and cancer status in Cameroon.

    Science.gov (United States)

    Tchana, Angele N; Moundipa, Paul F; Tchouanguep, Félicité M

    2010-01-01

    Aflatoxins are food contaminants usually associated with hepatitis, immunodepression, impairment of fertility and cancer. The present work was to determine the presence of aflatoxins in eggs, milk, urine, and blood samples that were collected from various sources and periods; and hepatitis B virus antigen in blood samples. Aflatoxin was found in eggs (45.2%), cow raw milk (15.9%), breast milk (4.8%), urine from kwashiorkor and marasmic kwashiorkor children (45.5%), and sera from primary liver cancer patients (63.9%); HbsAg was also detected in 69.4% of the serum samples, but there was no association between both factors. Both AF and hepatitis B virus seem to be risk factors that could increase the incidence and prevalence rates of malnutrition and cancer in Cameroon.

  11. An economic comparison of typical dairy farming systems in South Africa, Morocco, Uganda and Cameroon.

    Science.gov (United States)

    Ndambi, Oghaiki Asaah; Hemme, Torsten

    2009-08-01

    Population growth, urbanisation and increased per capita milk consumption are main reasons for recent increasing milk demand in Africa. Due to globalisation, it is important to know how competitive various production systems are, especially as most governments promote local production and disfavour dairy imports. The TIPI-CAL (Technology Impact, Policy Impact Calculations model) was used to analyse and compare costs and returns of predominant dairy farming systems in South Africa, Morocco, Uganda and Cameroon. Results show that, as farms grew larger in size, family resources (especially land and labour) became insufficient and there was need for their acquisition from external sources. Though extensive dairy farming systems had the lowest cost of milk production (Africa had relatively low costs (Investment (ROI) due to a higher efficiency of input utilisation. It was concluded that, intensification of dairy farming and simultaneously increasing the scale of production will greatly increase productivity of farm inputs, thus recommended for development of the dairy sector in African countries.

  12. TOURISTY POLICIES AND THE HOTEL PARK DEVELOPEMENT OF CAMEROON (1950 - 2003

    Directory of Open Access Journals (Sweden)

    Violeta PUŞCAŞU

    2009-06-01

    Full Text Available The hotelier component represents an important side of the touristy activity success. In countries that have an emergent economy, as Cameroon, the tourism and the hotel business have shaped activation as a lever to the whole economy, since the second half of the 20th century. The present paperwork proposes an analytic overview of the evolution of the hotelier park in two of the main cities of the country, Douala and Yaoundé. The evolutional aspects are historically staged, correlated within the political framework and emphasize the tourist phenomenon overall. The goals of our research emphasize qualitative and quantitative upheaval recorded by the urban hotelier park for the identification of the causal terms between the phenomenon type relations/context and the possible substantiation policy in the future.

  13. Current practice of epidemiology in Africa: highlights of the 3rd conference of the African epidemiological association and 1st conference of the Cameroon society of epidemiology, Yaoundé, Cameroon, 2014.

    Science.gov (United States)

    Nkwescheu, Armand Seraphin; Fokam, Joseph; Tchendjou, Patrice; Nji, Akindeh; Ngouakam, Hermann; Andre, Bita Fouda; Joelle, Sobngwi; Uzochukwu, Benjamin; Akinroye, Kingsley; Mbacham, Wilfred; Colizzi, Vittorio; Leke, Rose; Victora, Cesar

    2015-01-01

    As the study of disease occurrence and health indicators in human populations, Epidemiology is a dynamic field that evolves with time and geographical context. In order to update African health workers on current epidemiological practices and to draw awareness of early career epidemiologists on concepts and opportunities in the field, the 3(rd) African Epidemiology Association and the 1st Cameroon Society of Epidemiology Conference was organized in June 2-6, 2014 at the Yaoundé Mont Febe Hotel, in Cameroon. Under the theme«Practice of Epidemiology in Africa: Stakes, Challenges and Perspectives», the conference attracted close to five hundred guest and participants from all continents. The two main programs were the pre-conference course for capacity building of African Early Career epidemiologists, and the conference itself, providing a forum for scientific exchanges on recent epidemiological concepts, encouraging the use of epidemiological methods in studying large disease burden and neglected tropical diseases; and highlighting existing opportunities.

  14. Heat impact on schoolchildren in Cameroon, Africa: potential health threat from climate change

    Directory of Open Access Journals (Sweden)

    Tord Kjellstrom

    2010-11-01

    Full Text Available Background: Health impacts related to climate change are potentially an increasing problem in Cameroon, especially during hot seasons when there are no means for protective and adaptive actions. Objective: To describe environmental conditions in schools and to evaluate the impact of heat on schoolchildren's health during school days in the Cameroon cities of Yaoundé and Douala. Methods: Schoolchildren (N=285 aged 12–16 years from public secondary schools completed a questionnaire about their background, general symptoms, and hot feelings in a cross-sectional study. In Yaoundé, 50 schoolchildren were individually interviewed during school days about hourly symptoms (fatigue, headache, and feeling very hot and performance. Lascar dataloggers were used to measure indoor classroom temperatures and humidity. Results: There was a significant correlation between daily indoor temperature and the percentages of schoolchildren who felt very hot, had fatigue, and headaches in Yaoundé. A high proportion of schoolchildren felt very hot (48%, had fatigue (76%, and headaches (38% in Yaoundé. Prevalences (% were higher among girls than boys for headaches (58 vs 39, feeling ‘very hot overall’ (37 vs 21, and ‘very hot in head’ (21 vs 18. Up to 62% were absentminded and 45% had slow writing speed. High indoor temperatures of 32.5°C in Yaoundé and 36.6°C in Douala were observed in school. Conclusions: Headache, fatigue, and feeling very hot associated with high indoor air temperature were observed among schoolchildren in the present study. Longitudinal data in schools are needed to confirm these results. School environmental conditions should be improved in order to enhance learning.

  15. Oral Health Status of the Elderly at Tonga, West Region, Cameroon

    Science.gov (United States)

    Michele Lolita, Yotat; Ashu Michael, Agbor; Hubert, Ntumba; Florence, Djachechi; Jacques, Bolenge

    2015-01-01

    Objectives. The aim of this study was to determine the oral health status of elderly persons in Tonga, West Region of Cameroon. Methodology. This is a cross-sectional study of persons of at least 65 years, living in Tonga village, West Region of Cameroon. Results. A total of 183 persons aged between 65 and 94 years, mean age of 73 years ±7 s.d., 83 (45,4%) males, and 100 (54,6%) females participated in the study. The most represented age range was 65–74 years (60.1%); 86 (47.3%) and elders above 65 constituted 1.8% of the total population. More than a third 117 (41.4%) had visible dental plaque, 117 (48,6%) had periodontal pockets >4 mm, 153 (54,1%) had teeth with total crown destruction, 70 (38.3%) had not lost a tooth, 23 (12.6%) had lost 1 tooth, 19 (10.4%) have lost at least 2 teeth, 100 (55.7%) were partially edentulous at the maxilla and 98 (53.6%) at the mandible, 2 (1.1%) were completely edentulous at the maxilla and 3 (1.6%) at the mandible, and 3.8% had removable dentures. The mean DMF index was 6.11 and 69.4% had dental caries. Risk factors to dental caries were toothbrushing and tobacco consumption while dental plaque was associated to pocket depth of 4–6 mm. Barriers to oral health care included ignorance 47 (25.7%), financial difficulties 124 (67.8%), and distance to the nearest clinic 12 (6.5%). Conclusion. The oral status of the elderly was generally poor. PMID:26633972

  16. Oral Health Status of the Elderly at Tonga, West Region, Cameroon

    Directory of Open Access Journals (Sweden)

    Yotat Michele Lolita

    2015-01-01

    Full Text Available Objectives. The aim of this study was to determine the oral health status of elderly persons in Tonga, West Region of Cameroon. Methodology. This is a cross-sectional study of persons of at least 65 years, living in Tonga village, West Region of Cameroon. Results. A total of 183 persons aged between 65 and 94 years, mean age of 73 years ±7 s.d., 83 (45,4% males, and 100 (54,6% females participated in the study. The most represented age range was 65–74 years (60.1%; 86 (47.3% and elders above 65 constituted 1.8% of the total population. More than a third 117 (41.4% had visible dental plaque, 117 (48,6% had periodontal pockets >4 mm, 153 (54,1% had teeth with total crown destruction, 70 (38.3% had not lost a tooth, 23 (12.6% had lost 1 tooth, 19 (10.4% have lost at least 2 teeth, 100 (55.7% were partially edentulous at the maxilla and 98 (53.6% at the mandible, 2 (1.1% were completely edentulous at the maxilla and 3 (1.6% at the mandible, and 3.8% had removable dentures. The mean DMF index was 6.11 and 69.4% had dental caries. Risk factors to dental caries were toothbrushing and tobacco consumption while dental plaque was associated to pocket depth of 4–6 mm. Barriers to oral health care included ignorance 47 (25.7%, financial difficulties 124 (67.8%, and distance to the nearest clinic 12 (6.5%. Conclusion. The oral status of the elderly was generally poor.

  17. Household and community socioeconomic and environmental determinants of child nutritional status in Cameroon

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    Pongou Roland

    2006-04-01

    Full Text Available Abstract Background Undernutrition is a leading cause of child mortality in developing countries, especially in sub-Saharan Africa. We examine the household and community level socioeconomic and environmental factors associated with child nutritional status in Cameroon, and changes in the effects of these factors during the 1990s economic crisis. We further consider age-specific effects of household economic status on child nutrition. Methods Child nutritional status was measured by weight-for-age (WAZ and height-for-age (HAZ z-scores. Data were from Demographic and Health Surveys conducted in 1991 and 1998. We used analysis of variance to assess the bivariate association between the explanatory factors and nutritional status. Multivariate, multilevel analyses were undertaken to estimate the net effects of both household and community factors. Results Average WAZ and HAZ declined respectively from -0.70 standard deviations (SD, i.e. 0.70 SD below the reference median, to -0.83 SD (p = 0.006 and from -1.03 SD to -1.14 SD (p = 0.026 between 1991 and 1998. These declines occurred mostly among boys, children over 12 months of age, and those of low socioeconomic status. Maternal education and maternal health seeking behavior were associated with better child nutrition. Household economic status had an overall positive effect that increased during the crisis, but it had little effect in children under 6 months of age. Improved household (water, sanitation and cooking fuel and community environment had positive effects. Children living in the driest regions of the country were consistently worst off, and those in the largest cities were best off. Conclusion Both household and community factors have significant impact on child health in Cameroon. Understanding these relationships can facilitate design of age- and community-specific intervention programs.

  18. From grass to grace: How SLMTA revolutionised the Bamenda Regional Hospital Laboratory in Cameroon

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    Siyem C. Nkwawir

    2014-09-01

    Full Text Available Background: Public health laboratories form the foundation on which today’s clinical laboratory practice in Cameroon is built. The advent of the Strengthening Laboratory Management Toward Accreditation (SLMTA programme in 2009 empowered the Bamenda Regional Hospital Laboratory (BRHL to improve its working culture, practices and management.Objectives: To evaluate the results of SLMTA implementation at BRHL and discuss lessons learned.Method: In 2010, the SLMTA programme was rolled out in Cameroon to improve laboratory quality management systems in five laboratories, including BRHL. Three workshops were conducted (the first centralised, the remaining two on-site at each laboratory and improvement projects were implemented after each workshop with the assistance of mentors. Audits were used in order to evaluate performance and to identify areas for further improvement.Results: BRHL had the lowest score (18% amongst the cohort at the baseline audit and the highest (81% at the official Stepwise Laboratory Quality Improvement Process Towards Accreditation (SLIPTA audit conducted in August 2013 by the African Society for Laboratory Medicine. Improvements were observed in each of the 12 Quality System Essentials; improvement was especially noteworthy in the areas of facilities and safety, and purchasing and inventory. Staff investment and pride in the quality of laboratory services increased.Conclusion: BRHL’s remarkable improvement was achieved with a combination of SLMTA training activities, intensive on-site mentorship and the collective focus of all laboratory staff. The experience at Bamenda Hospital illustrates what can be achieved when a laboratory successfully harnesses the energy of its staff and implements changes to improve the quality of services in a transformation taking them from grass to grace.

  19. Epidemiology and genetic variability of HHV-8/KSHV in Pygmy and Bantu populations in Cameroon.

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    Edouard Betsem

    2014-05-01

    Full Text Available BACKGROUND: Kaposi's sarcoma associated herpesvirus (KSHV/HHV-8 is the causal agent of all forms of Kaposi sarcoma. Molecular epidemiology of the variable K1 region identified five major subtypes exhibiting a clear geographical clustering. The present study is designed to gain new insights into the KSHV epidemiology and genetic diversity in Cameroon. METHODOLOGY/PRINCIPAL FINDINGS: Bantu and Pygmy populations from remote rural villages were studied. Antibodies directed against latent nuclear antigens (LANA were detected by indirect immunofluorescence using BC3 cells. Peripheral blood cell DNAs were subjected to a nested PCR amplifying a 737 bp K1 gene fragment. Consensus sequences were phylogenetically analyzed. We studied 2,063 persons (967 females, 1,096 males, mean age 39 years, either Bantus (1,276 or Pygmies (787. The Bantu group was older (42 versus 35 years: P<10(-4. KSHV anti-LANA seroprevalence was of 37.2% (768/2063, with a significant increase with age (P<10(-4 but no difference according to sex. Seroprevalence, as well as the anti-LANA antibodies titres, were higher in Bantus (43.2% than in Pygmies (27.6% (P<10(-4, independently of age. We generated 29 K1 sequences, comprising 24 Bantus and five Pygmies. These sequences belonged to A5 (24 cases or B (five cases subtypes. They exhibited neither geographical nor ethnic aggregation. A5 strains showed a wide genetic diversity while the B strains were more homogenous and belonged to the B1 subgroup. CONCLUSION: These data demonstrate high KSHV seroprevalence in the two major populations living in Southern and Eastern Cameroon with presence of mostly genetically diverse A5 but also B K1 subtypes.

  20. Strengths and weaknesses of the smallholder oil palm sector in Cameroon

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    Nkongho Raymond N.

    2014-03-01

    Full Text Available The present study is an evaluation of the current strengths and weaknesses of the oil palm smallholder sector in Cameroon, or more precisely of the non-industrial sector, as some holdings owned by elites can reach hundreds of hectares. A randomized sample of oil palm producers was chosen after categorization into elites, migrants, natives and company workers (past and present in four palm oil production basins in the Southern part of the country. 176 semi-structured questionnaires were administered. The production basins included: Eseka, Dibombari, Muyuka, and Lobe. Results from the study revealed that elites owned larger average areas (41.3 ha than the other categories of oil palm producers. All categories recorded low average plantation yields, ranging from 7 to 8.4 t FFB/ha/year (with minimum yields of 3 t FFB/ha. Though the elites showed better bargaining power and higher income, all categories of producers faced similar problems such as the high cost of inputs with no governmental subsidies, the difficulty in accessing loans with low interest rates and the use of rudimentary working tools. Despite such weaknesses, the sector also demonstrates some strengths such as the ability to impose little threat to the primary forest when compared to agro-industrial plantations, the availability of a domestic and sub-regional market for red palm oil, the availability of artisanal mills with low extraction rates although able to generate more income for the producers. There is a need for governmental policies that will strengthen partnership between small and medium oil palm producers and agro-industries as it was the case during the Fonader period, in order to converge with the poverty reduction strategy intiated by the government of Cameroon.

  1. A survey of knowledge, attitudes and practice of emergency contraception among university students in Cameroon

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    Kouam Luc

    2007-07-01

    Full Text Available Abstract Background Unsafe abortion is a major public health problem in low-and-middle income countries. Young and unmarried women constitute a high risk group for unsafe abortions. It has been estimated that widespread use of emergency contraception may significantly reduce the number of abortion-related morbidity and mortality. The purpose of this study was to evaluate the knowledge, attitudes and experiences on emergency contraceptive pills by the university students in Cameroon in order to develop and refine a national health programme for reducing unwanted pregnancies and their associated morbidity and mortality. Methods A convenient sample of 700 students of the University of Buea (Cameroon was selected for the study. Data was collected by a self-administered, anonymous and pre-tested questionnaire. Results The response rate was 94.9% (664/700. General level of awareness of emergency contraceptive pills was 63.0% (418/664. However, knowledge of the general features of emergency contraceptive pills was low and misinformation was high among these students. Knowledge differed according to the source of information: informal source was associated with misinformation, while medical and informational sources were associated with better knowledge. Although the students generally had positive attitudes regarding emergency contraceptive pills, up to 65.0% (465/664 believed that emergency contraceptive pills were unsafe. Those with adequate knowledge generally showed favourable attitudes with regards to emergency contraceptive pills (Mann-Whitney U = 2592.5, p = 0.000. Forty-nine students (7.4% had used emergency contraceptive pills themselves or had a partner who had used them. Conclusion Awareness of emergency contraception pills by Cameroonian students is low and the method is still underused. Strategies to promote use of emergency contraception should be focused on spreading accurate information through medical and informational sources, which

  2. Hepatitis B, HIV, and Syphilis Seroprevalence in Pregnant Women and Blood Donors in Cameroon

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    Jodie Dionne-Odom

    2016-01-01

    Full Text Available Objectives. We estimated seroprevalence and correlates of selected infections in pregnant women and blood donors in a resource-limited setting. Methods. We performed a cross-sectional analysis of laboratory seroprevalence data from pregnant women and voluntary blood donors from facilities in Cameroon in 2014. Rapid tests were performed to detect hepatitis B surface antigen, syphilis treponemal antibodies, and HIV-1/2 antibodies. Blood donations were also tested for hepatitis C and malaria. Results. The seroprevalence rates and ranges among 7069 pregnant women were hepatitis B 4.4% (1.1–9.6%, HIV 6% (3.0–10.2%, and syphilis 1.7% (1.3–3.8% with significant variability among the sites. Correlates of infection in pregnancy in adjusted regression models included urban residence for hepatitis B (aOR 2.9, CI 1.6–5.4 and HIV (aOR 3.5, CI 1.9–6.7. Blood donor seroprevalence rates and ranges were hepatitis B 6.8% (5.0–8.8%, HIV 2.2% (1.4–2.8%, syphilis 4% (3.3–4.5%, malaria 1.9%, and hepatitis C 1.7% (0.5–2.5%. Conclusions. Hepatitis B, HIV, and syphilis infections are common among pregnant women and blood donors in Cameroon with higher rates in urban areas. Future interventions to reduce vertical transmission should include universal screening for these infections early in pregnancy and provision of effective prevention tools including the birth dose of univalent hepatitis B vaccine.

  3. Retention in an antiretroviral therapy programme during an era of decreasing drug cost in Limbe, Cameroon

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    Mosoko Jembia J

    2011-06-01

    Full Text Available Abstract Background In 2002, Cameroon initiated scale up of antiretroviral therapy (ART; on 1 October 2004, a substantial reduction in ART cost occurred. We assessed the impact of this event and other factors on enrolment and retention in care among HIV-infected patients initiating ART from February 2002 to December 2005 at the single ART clinic serving the Southwest Region in Limbe, Cameroon. Methods We retrospectively analyzed clinical and pharmacy payment records of HIV-infected patients initiating ART according to national guidelines. We compared two cohorts of patients, enrolled before and after 1 October 2004, to determine if price reduction was associated with enhanced enrolment. We assessed factors associated with retention and survival by Cox proportional hazards models. Retention in care implied patients who had contact with the healthcare system as of 31 December 2005 (including those who were transferred to continue care in other ART centres, although these patients may have interrupted therapy at some time. A patient who was not retained in care may have dropped out (lost to follow up or died. Results Mean enrolment rates for 2920 patients who initiated ART before and after the price reduction were 46.5 and 95.5 persons/month, respectively (p Conclusions Reducing the cost of ART increased enrolment of clients in the programme, but did not change retention in care. In a system where most clients pay for ART, an accessible clinic location may be more important than the cost of medication for retention in care. Decentralizing ART clinics might improve retention and survival among patients on ART.

  4. Chronic non-communicable diseases in Cameroon - burden, determinants and current policies

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    Echouffo-Tcheugui Justin B

    2011-11-01

    Full Text Available Abstract Cameroon is experiencing an increase in the burden of chronic non-communicable diseases (NCDs, which accounted for 43% of all deaths in 2002. This article reviews the published literature to critically evaluate the evidence on the frequency, determinants and consequences of NCDs in Cameroon, and to identify research, intervention and policy gaps. The rising trends in NCDs have been documented for hypertension and diabetes, with a 2-5 and a 10-fold increase in their respective prevalence between 1994 and 2003. Magnitudes are much higher in urban settings, where increasing prevalence of overweight/obesity (by 54-82% was observed over the same period. These changes largely result from the adoption of unfavorable eating habits, physical inactivity, and a probable increasing tobacco use. These behavioral changes are driven by the economic development and social mobility, which are part of the epidemiologic transition. There is still a dearth of information on chronic respiratory diseases and cancers, as well as on all NDCs and related risk factors in children and adolescents. More nationally representative data is needed to tract risk factors and consequences of NCDs. These conditions are increasingly been recognized as a priority, mainly through locally generated evidence. Thus, national-level prevention and control programs for chronic diseases (mainly diabetes and hypertension have been established. However, the monitoring and evaluation of these programs is necessary. Budgetary allocations data by the ministry of health would be helpful, to evaluate the investment in NCDs prevention and control. Establishing more effective national-level tobacco control measures and food policies, as well as campaigns to promote healthy diets, physical activity and tobacco cessation would probably contribute to reducing the burden of NCDs.

  5. Measles outbreak in a poorly vaccinated region in Cameroon: a case series study, public health challenges and recommendations.

    Science.gov (United States)

    Njim, Tsi; Aminde, Leopold Ndemnge; Feteh, Fambombi Vitalis; Ngum, Joel Mbigha; Moustapha, Chandini Aliyou

    2015-01-01

    Measles is a highly contagious viral infection and still a leading cause of vaccine-preventable deaths in Africa; especially in unvaccinated populations. We reviewed the medical reports of the measles outbreak that occurred in Misaje, in the North west region of Cameroon from 11/03/2015 to 14/05/2015. Six measles cases were recorded during this period; three of them complicated by bacterial infections. Measles should be considered as a differential diagnosis for any febrile rash especially among poorly vaccinated populations. Primary preventive methods implemented by clinicians could help control outbreaks; especially with delays in public health intervention. Also, gaps in health policies in Cameroon should be addressed to scale up vaccination coverage in remote communities like Misaje to reduce the incidence of measles outbreaks.

  6. Linking Child Health, Maternal Labour Force Participation and Household Asset Endowments in Cameroon: What the People Say

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    Mbu Daniel TAMBI

    2014-11-01

    Full Text Available This paper is entitled “Linking Child Health, Maternal Labour Force Participation and Household Asset Endowments in Cameroon: what the people say”. The objectives are: (i document the determinants of child health as informed by focus group discussion, (ii analyze what the people say concerning the relationship between child health and maternal labour force participation, (iii explore the perception of the people on the effects of child health on asset accumulation and (iv suggest public policies on the basis of the findings. We used seven focus groups derived from different backgrounds in our framework. We observed that, parents make used of the extra time accrue to them due to better health for their children and family to do extra work that fetched them more money. Based on this, we recommend that decision makers should promote child health outcomes as it’s a tool to promote maternal labour and wealth accumulation in Cameroon

  7. Attainment of MDGs through tourism in the Central African sub-region: Implications for local economic development in Cameroon

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    Albert N. Kimbu

    2012-03-01

    Full Text Available This paper examines the role and contribution of tourism to local economic development and in the attainment of the Millennium Development Goals one and seven dealing with extreme poverty alleviation and environmental sustainability in the biodiversity endowed Central African sub-region. The concepts of sustainable tourism development and local economic development (in sub-Saharan Africa are examined. Through field observations and semi-structured interviews with 21 tourism industry stakeholders in Cameroon, an analysis of tourism’s role and future in LED and in the attainment of the Millennium Development Goals 1 & 7 is undertaken. The core challenges presently inhibiting tourism’s development thereby limiting its contribution to local economic development and the attainment of these goals in Cameroon are identified and a framework within which tourism’s contribution can be increased is proposed.

  8. Volcanic caves of East Africa - an overview

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    Jim W. Simons

    1998-01-01

    Full Text Available Numerous Tertiary to recent volcanoes are located in East Africa. Thus, much of the region is made up volcanic rock, which hosts the largest and greatest variety of East Africas caves. Exploration of volcanic caves has preoccupied members of Cave Exploration Group of East Africa (CEGEA for the past 30 years. The various publications edited by CEGEA are in this respect a treasure troves of speleological information. In the present paper an overview on the most important volcanic caves and areas are shortly reported.

  9. Toward Forecasting Volcanic Eruptions using Seismic Noise

    CERN Document Server

    Brenguier, Florent; Campillo, Michel; Ferrazzini, Valerie; Duputel, Zacharie; Coutant, Olivier; Nercessian, Alexandre

    2007-01-01

    During inter-eruption periods, magma pressurization yields subtle changes of the elastic properties of volcanic edifices. We use the reproducibility properties of the ambient seismic noise recorded on the Piton de la Fournaise volcano to measure relative seismic velocity variations of less than 0.1 % with a temporal resolution of one day. Our results show that five studied volcanic eruptions were preceded by clearly detectable seismic velocity decreases within the zone of magma injection. These precursors reflect the edifice dilatation induced by magma pressurization and can be useful indicators to improve the forecasting of volcanic eruptions.

  10. Mapping the topography and cone morphology of the Dalinor volcanic swarm in Inner Mongolia with remote sensing and DEM data

    Science.gov (United States)

    Gong, Liwen; Li, Ni; Fan, Qicheng; Zhao, Yongwei; Zhang, Liuyi; Zhang, Chuanjie

    2016-09-01

    The Dalinor volcanic swarm, located south of Xilinhot, Inner Mongolia of China, was a result of multistage eruptions that occurred since the Neogene period. This swarm is mainly composed of volcanic cones and lava tablelands. The objective of this study is to map the topography and morphology of this volcanic swarm. It is based on a variety of data collected from various sources, such as the digital elevation model (DEM), Landsat images, and a 1:50,000 topographic map, in addition to various software platforms, including ArcGIS, Envi4.8, Global Mapper, and Google Earth for data processing and interpretation. The results show that the overall topography of the volcanic swarm is a platform with a central swell having great undulation, sizable gradient variations, a rough surface, and small terrain relief. According to the undulating characteristics of the line profile, the volcanic swarm can be divided into four stairs with heights of 1,280 m, 1,360 m, 1,440 m, and 1,500 m. The analysis of the swath profile characterizes the two clusters of volcanoes with different height ranges and evolution. The lava tablelands and volcanic cones are distributed in nearly EW-trending belts, where tableland coverage was delineated with superposed layers of gradients and degrees of relief. According to the morphology, the volcanic cones were classified into four types: conical, composite, dome, and shield. The formation causes and classification basis for each type of volcanic cone were analyzed and their parameters were extracted. The H/D ratios of all types of volcanic cones were then statistically determined and projected to create a map of volcanic density distribution. Based on the relationship between distribution and time sequence of the formation of different volcanic cones, it can be inferred that the volcanic eruptions migrated from the margins to the center of the lava plateau. The central area was formed through superposition of multi-stage eruptive materials. In addition

  11. Volcanic Plume Measurements with UAV (Invited)

    Science.gov (United States)

    Shinohara, H.; Kaneko, T.; Ohminato, T.

    2013-12-01

    Volatiles in magmas are the driving force of volcanic eruptions and quantification of volcanic gas flux and composition is important for the volcano monitoring. Recently we developed a portable gas sensor system (Multi-GAS) to quantify the volcanic gas composition by measuring volcanic plumes and obtained volcanic gas compositions of actively degassing volcanoes. As the Multi-GAS measures variation of volcanic gas component concentrations in the pumped air (volcanic plume), we need to bring the apparatus into the volcanic plume. Commonly the observer brings the apparatus to the summit crater by himself but such measurements are not possible under conditions of high risk of volcanic eruption or difficulty to approach the summit due to topography etc. In order to overcome these difficulties, volcanic plume measurements were performed by using manned and unmanned aerial vehicles. The volcanic plume measurements by manned aerial vehicles, however, are also not possible under high risk of eruption. The strict regulation against the modification of the aircraft, such as installing sampling pipes, also causes difficulty due to the high cost. Application of the UAVs for the volcanic plume measurements has a big advantage to avoid these problems. The Multi-GAS consists of IR-CO2 and H2O gas analyzer, SO2-H2O chemical sensors and H2 semiconductor sensor and the total weight ranges 3-6 kg including batteries. The necessary conditions of the UAV for the volcanic plumes measurements with the Multi-GAS are the payloads larger than 3 kg, maximum altitude larger than the plume height and installation of the sampling pipe without contamination of the exhaust gases, as the exhaust gases contain high concentrations of H2, SO2 and CO2. Up to now, three different types of UAVs were applied for the measurements; Kite-plane (Sky Remote) at Miyakejima operated by JMA, Unmanned airplane (Air Photo Service) at Shinomoedake, Kirishima volcano, and Unmanned helicopter (Yamaha) at Sakurajima

  12. Bacillus anthracis Diversity and Geographic Potential across Nigeria, Cameroon and Chad: Further Support of a Novel West African Lineage

    OpenAIRE

    2015-01-01

    Zoonoses, diseases affecting both humans and animals, can exert tremendous pressures on human and veterinary health systems, particularly in resource limited countries. Anthrax is one such zoonosis of concern and is a disease requiring greater public health attention in Nigeria. Here we describe the genetic diversity of Bacillus anthracis in Nigeria and compare it to Chad, Cameroon and a broader global dataset based on the multiple locus variable number tandem repeat (MLVA-25) genetic typing ...

  13. Evaluation of bovine (Bos indicus) ovarian potential for in vitro embryo production in the Adamawa plateau (Cameroon)

    OpenAIRE

    2014-01-01

    An abattoir study was conducted to evaluate the ovarian potential of 201 local zebu cattle from Ngaoundere, Adamawa region (Cameroon) for in vitro embryo production (IVEP). The ovaries were excised, submerged in normal saline solution (0.9%) and transported to the laboratory for a detailed evaluation. Follicles on each ovary were counted, their diameters (Φ) measured and were grouped into 3 categories: small (Φ 8 mm). Each ovary was then sliced in...

  14. Characteristics of anti-hepatitis C virus antibody-positive patients in a hospital setting in Douala, Cameroon

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    Henry Namme Luma

    2016-04-01

    Conclusions: In the gastroenterology clinic of Douala General Hospital, while almost 40% of patients who were anti-HCV antibody-positive were asymptomatic and diagnosed fortuitously, some already presented complications, including cirrhosis and hepatocellular carcinoma. There is an urgent need to put in place programs to increase awareness and diagnosis of HCV infection and to develop extensive and targeted anti-HCV treatment guidelines to improve the management of these patients in Cameroon.

  15. Four new species of Cichlidogyrus (Monogenea, Ancyrocephalidae) from Sarotherodon mvogoi and Tylochromis sudanensis (Teleostei, Cichlidae) in Cameroon

    OpenAIRE

    Pariselle, Antoine; Bitja Nyom, A. R.; Bilong Bilong, C.F.

    2014-01-01

    The four Cichlidogyrus species (Monogenea, Ancyrocephalidae) found on the gills of Sarotherodon mvogoi and Tylochromis sudanensis (Teleostei, Cichlidae) in Cameroon are considered new and are described herein. Cichlidogyrus mvogoi n. sp. from Sarotherodon mvogoi, characterised by a long (> 100 mu m), thin and spirally coiled penis and a short marginal hook pair I. Cichlidogyrus sigmocirrus n. sp. from Tylochromis sudanensis, characterised by a short marginal hook pair I, a slightly spirally c...

  16. Aquaculture in Cameroon and potential of lactic acid bacteria to be used as diseases controlling agents. A Review

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    Kaktchan, Pierre Marie

    2015-08-01

    Full Text Available Aquaculture is the world’s fastest growing food production sector and can be a great solution to the massive demand for protein of animal due to increase in the Cameroonian population. This review summarizes the past and present status of fish aquaculture in Cameroon, the new challenges for intensifying fish production and evaluates the possibility of using lactic acid bacteria as disease control agents in order to overcome these challenges. Fish farming started in Cameroon in the late 1940s, and has seen little progress since the last ten years, but the production is still insufficient to meet the demand of the population estimated at 400 000 tons in 2015. In order to reduce massive fish imports, Cameroon plans to produce 100 000 tons of fish by commercial aquaculture. Achieving this task needs quality and quantity of fingerlings, and probiotic lactic acid bacteria instead of antibiotics could be used as disease control agents in young fish hatching and ponds in order to boost and ensure quality and quantity production.

  17. The substitution of mineral fertilizers by compost from household waste in Cameroon: economic analysis with a partial equilibrium model.

    Science.gov (United States)

    Jaza Folefack, Achille Jean

    2009-05-01

    This paper analyses the possibility of substitution between compost and mineral fertilizer in order to assess the impact on the foreign exchange savings in Cameroon of increasing the use of compost. In this regard, a partial equilibrium model was built up and used as a tool for policy simulations. The review of existing literature already suggests that, the compost commercial value i.e. value of substitution (33,740 FCFA tonne(-1)) is higher compared to the compost real price (30,000 FCFA tonne(-1)), proving that it could be profitable to substitute the mineral fertilizer by compost. Further results from the scenarios used in the modelling exercise show that, increasing the compost availability is the most favourable policy for the substitution of mineral fertilizer by compost. This policy helps to save about 18.55% of the annual imported mineral fertilizer quantity and thus to avoid approximately 8.47% of the yearly total import expenditure in Cameroon. The policy of decreasing the transport rate of compost in regions that are far from the city is also favourable to the substitution. Therefore, in order to encourage the substitution of mineral fertilizer by compost, programmes of popularization of compost should be highlighted and be among the top priorities in the agricultural policy of the Cameroon government.

  18. Volcanic Ash Advisory Database, 1983-2003

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Volcanic ash is a significant hazard to aviation and can also affect global climate patterns. To ensure safe navigation and monitor possible climatic impact, the...

  19. Volcanics in the Gulf Coast [volcanicg

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The volcanic provinces are modified after Plate 2, Principal structural features, Gulf of Mexico Basin (compiled by T.E. Ewing and R.F. Lopez) in Volume J, The...

  20. Volcanism and associated hazards: the Andean perspective

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    R. I. Tilling

    2009-12-01

    Full Text Available Andean volcanism occurs within the Andean Volcanic Arc (AVA, which is the product of subduction of the Nazca Plate and Antarctica Plates beneath the South America Plate. The AVA is Earth's longest but discontinuous continental-margin volcanic arc, which consists of four distinct segments: Northern Volcanic Zone, Central Volcanic Zone, Southern Volcanic Zone, and Austral Volcanic Zone. These segments are separated by volcanically inactive gaps that are inferred to indicate regions where the dips of the subducting plates are too shallow to favor the magma generation needed to sustain volcanism. The Andes host more volcanoes that have been active during the Holocene (past 10 000 years than any other volcanic region in the world, as well as giant caldera systems that have produced 6 of the 47 largest explosive eruptions (so-called "super eruptions" recognized worldwide that have occurred from the Ordovician to the Pleistocene.

    The Andean region's most powerful historical explosive eruption occurred in 1600 at Huaynaputina Volcano (Peru. The impacts of this event, whose eruptive volume exceeded 11 km3, were widespread, with distal ashfall reported at distances >1000 km away. Despite the huge size of the Huaynaputina eruption, human fatalities from hazardous processes (pyroclastic flows, ashfalls, volcanogenic earthquakes, and lahars were comparatively small owing to the low population density at the time. In contrast, lahars generated by a much smaller eruption (<0.05 km3 in 1985 of Nevado del Ruiz (Colombia killed about 25 000 people – the worst volcanic disaster in the Andean region as well as the second worst in the world in the 20th century. The Ruiz tragedy has been attributed largely to ineffective communications of hazards information and indecisiveness by government officials, rather than any major deficiencies in scientific data. Ruiz's disastrous outcome, however, together with responses to subsequent

  1. About the Mechanism of Volcanic Eruptions

    CERN Document Server

    Nechayev, Andrei

    2012-01-01

    A new approach to the volcanic eruption theory is proposed. It is based on a simple physical mechanism of the imbalance in the system "magma-crust-fluid". This mechanism helps to explain from unified positions the different types of volcanic eruptions. A criterion of imbalance and magma eruption is derived. Stratovolcano and caldera formation is analyzed. High explosive eruptions of the silicic magma is discussed

  2. Episodic Volcanism and Geochemistry in Western Nicaragua

    Science.gov (United States)

    Saginor, I.; Carr, M. J.; Gazel, E.; Swisher, C.; Turrin, B.

    2007-12-01

    The active volcanic arc in western Nicaragua is separated from the Miocene arc by a temporal gap in the volcanic record, during which little volcanic material was erupted. Previous work suggested that this gap lasted from 7 to 1.6 Ma, during which volcanic production in Nicaragua was limited or nonexistent. Because the precise timing and duration of this gap has been poorly constrained, recent fieldwork has focused on locating samples that may have erupted close to or even during this apparent hiatus in activity. Recent 40Ar/39Ar dates reveal pulses of low- level episodic volcanism at 7 Ma and 1 Ma between the active and Miocene arcs with current volcanism beginning ~350 ka. In addition, sampling from an inactive area between Coseguina and San Cristobal yielded two distinct groupings of ages; one of Tamarindo age (13 Ma) and the other around 3.5 Ma-the only samples of that age collected on-strike with the active arc. This raises the possibility the bases of the other active volcanoes contain lavas that are older than expected, but have been covered by subsequent eruptions. The Miocene arc differs from the active arc in Central America in several ways, with the latter having higher Ba/La and U/Th values due to increased slab input and changes in subducted sediment composition. Analysis of sample C-51 and others taken from the same area may shed light on the timing of this shift from high to low Ba/La and U/Th values. More importantly, it may help explain why the arc experienced such a dramatic downturn in volcanic production during this time. We also report 25 new major and trace element analyses that shed some light on the origins of these minor episodes of Nicaraguan volcanism. These samples are currently awaiting Sr and Nd isotopic analyses.

  3. Cretaceous volcanic-intrusive magmatism in western Guangdong and its geological significance

    Institute of Scientific and Technical Information of China (English)

    GENG; Hongyan; XU; Xisheng; S.Y.O'Reilly; ZHAO; Ming; SUN; Tao

    2006-01-01

    Systematic zircon LA-ICPMS U-Pb dating reveals that Cretaceous volcanic-intrusive activities developed in western Guangdong. Representative volcanic rocks, i.e. Maanshan and Zhougongding rhyodacites, have zircon U-Pb isotopic ages of 100±1 Ma, and the intrusive ones including the Deqing monzonitic granite body and the Xinghua granodiorite body in the Shidong complex, as well as the Tiaocun granodiorite body in the Guangping complex yield ages of 99±2 Ma, ca.100 Ma, and 104±3 Ma respectively. The biotite-granites of the Shidong complex main body (461±35 Ma) and that of the Guangping complex (444±6 Ma) are Caledonian. In spite of the big time interval between Cretaceous volcanic-intrusive magmatisms and Caledonian intrusive ones, both of them are characterized by enrichment in Rb, Th, Ce, Zr, Hf, Sm, depletion in Ba, Nb, Ta, P, Ti, Eu, and weakly REE tetrad effect. Eu negative anomalies are: Cretaceous volcanic rocks (Eu/Eu*=0.74), Cretaceous intrusive rocks (Eu/Eu*=0.35-0.58), Caledonian biotite granites (Eu/Eu*=0.31-0.34). Studies of Sr-Nd isotope data show that all these igneous rocks have high initial 87Sr/86Sr ratios (0.7105-0.7518), and low εNd(t) values (-7.23--11.39) with their Nd two-stage model ages ranging from 1.6-2.0 Ga, which suggest that they all derived from the Proterozoic crustal basement of southeast China.The occurrence of Cretaceous volcanic-intrusive magmatisms in western Guangdong is related with the important lithospheric extension event in southeast China (including Nanling region) at ca. 100 Ma.The "volcanic line" defined by the large scale Mesozoic intermediate-acidic volcanic magmatisms in southeast China may further extend to the southwest margin of Nanling region.

  4. Lunar volcanism in space and time

    Science.gov (United States)

    Head, J. W., III

    1976-01-01

    The role of lunar volcanism in the history of the moon is documented using lunar-orbit and earth-based data along with characterizations derived from Apollo and Luna sample-return missions. Characteristics of mare and highland volcanic features are described, Apollo and Luna results are discussed, and the characteristics of other mare deposits and of other highland features of possible volcanic origin are summarized. Major conclusions are that: (1) there is little unequivocal morphologic evidence for highland volcanism, (2) lunar mare lavas appear to have originated from depths of 100 to 500 km, (3) impact melting does not appear to have been a factor in the generation of mare lavas, (4) mare volcanism was characterized by massive outpourings of very fluid volatile-poor lava analogous to terrestrial flood basalts, (5) mare volcanism took place from 3.83 to about 2.5 billion years ago, (6) the preferential occurrence of mare deposits in large impact basins appears to be generically unrelated to basin formation, and (7) a thicker farside crust may be responsible for the distinctive nearside-farside asymmetry of mare deposits.

  5. Volcanic loading: The dust veil index

    Energy Technology Data Exchange (ETDEWEB)

    Lamb, H.H. [Univ. of East Anglia, Norwich (United Kingdom). Climatic Research Unit

    1985-09-01

    Dust ejected into the high atmosphere during explosive volcanic eruptions has been considered as a possible cause for climatic change. Dust veils created by volcanic eruptions can reduce the amount of light reaching the Earth`s surface and can cause reductions in surface temperatures. These climatic effects can be seen for several years following some eruptions and the magnitude and duration of the effects depend largely on the density or amount of tephra (i.e. dust) ejected, the latitude of injection, and atmospheric circulation patterns. Lamb (1970) formulated the Dust Veil Index (DVI) in an attempt to quantify the impact on the Earth`s energy balance of changes in atmospheric composition due to explosive volcanic eruptions. The DVI is a numerical index that quantifies the impact on the Earth`s energy balance of changes in atmospheric composition due to explosive volcanic eruptions. The DVI is a numerical index that quantifies the impact of a particular volcanic eruptions release of dust and aerosols over the years following the event. The DVI for any volcanic eruptions are available and have been used in estimating Lamb`s dust veil indices.

  6. Field evaluation of rapid diagnostic tests for malaria in Yaounde, Cameroon.

    Science.gov (United States)

    Tahar, Rachida; Sayang, Collins; Ngane Foumane, Vincent; Soula, Georges; Moyou-Somo, Roger; Delmont, Jean; Basco, Leonardo K

    2013-02-01

    Rapid diagnostic tests (RDTs) are affordable, alternative diagnostic tools. The present study aimed to evaluate RDTs available in Cameroon and compare their characteristics to follow the parasitological response of patients for 28 days. Malaria diagnosis was assessed in 179 febrile patients using conventional microscopy as the reference method. Parascreen detects both Plasmodium falciparum-specific histidine-rich protein 2 (Pf HRP-2) and Pan-specific plasmodial lactate dehydrogenase (pLDH) in all four human Plasmodium spp. Diaspot is based on the detection of Pf HRP-2. OptiMAL-IT (pLDH specific for P. falciparum and pLDH for all four human Plasmodium spp.) was assessed for comparison. The reliability of RDTs was evaluated by calculating the sensitivity, specificity, positive predictive value, negative predictive value, false-positive rate, false-negative rate, and likelihood ratio. The clinical outcome of 18 children treated with atovaquone-proguanil and followed for 28 days was evaluated using microscopy and RDTs. Of 179 samples, 133 (74.3%) were pure P. falciparum-positive smears, 4 (2.2%) pure P. malariae-positive smears, and 42 (23.5%) negative smears. Parascreen and Diaspot had high sensitivity (>92%) and positive predictive values (>94%). The specificities for Parascreen and Diaspot were 81.0% and 90.5%, respectively. The false-positive rates and the false-negative rates were 19.0% and 4.5% for Parascreen and 9.5% and 8.3% for Diaspot, respectively. Most false-negatives occurred in samples with low parasitaemia (500 asexual parasites/μL). Four pure P. malariae were only detected by the pan-Plasmodium bands of Parascreen and OptiMAL-IT. In blood samples from patients treated and followed-up for 28 days, HRP2-based RDTs remained positive in most samples until Day 28. Despite negative smears, OptiMAL-IT remained positive in several patients until Day 7 but was negative in all patients from Day 14 onwards. RDTs can improve the management of febrile patients. The

  7. Addressing Health Workforce Distribution Concerns: A Discrete Choice Experiment to Develop Rural Retention Strategies in Cameroon

    Directory of Open Access Journals (Sweden)

    Paul Jacob Robyn

    2015-03-01

    Full Text Available Background Nearly every nation in the world faces shortages of health workers in remote areas. Cameroon is no exception to this. The Ministry of Public Health (MoPH is currently considering several rural retention strategies to motivate qualified health personnel to practice in remote rural areas. Methods To better calibrate these mechanisms and to develop evidence-based retention strategies that are attractive and motivating to health workers, a Discrete Choice Experiment (DCE was conducted to examine what job attributes are most attractive and important to health workers when considering postings in remote areas. The study was carried out between July and August 2012 among 351 medical students, nursing students and health workers in Cameroon. Mixed logit models were used to analyze the data. Results Among medical and nursing students a rural retention bonus of 75% of base salary (aOR= 8.27, 95% CI: 5.28-12.96, P< 0.001 and improved health facility infrastructure (aOR= 3.54, 95% CI: 2.73-4.58 respectively were the attributes with the largest effect sizes. Among medical doctors and nurse aides, a rural retention bonus of 75% of base salary was the attribute with the largest effect size (medical doctors aOR= 5.60, 95% CI: 4.12-7.61, P< 0.001; nurse aides aOR= 4.29, 95% CI: 3.11-5.93, P< 0.001. On the other hand, improved health facility infrastructure (aOR= 3.56, 95% CI: 2.75-4.60, P< 0.001, was the attribute with the largest effect size among the state registered nurses surveyed. Willingness-to-Pay (WTP estimates were generated for each health worker cadre for all the attributes. Preference impact measurements were also estimated to identify combination of incentives that health workers would find most attractive. Conclusion Based on these findings, the study recommends the introduction of a system of substantial monetary bonuses for rural service along with ensuring adequate and functional equipment and uninterrupted supplies. By focusing on

  8. Bionomics of Anopheline species and malaria transmission dynamics along an altitudinal transect in Western Cameroon

    Directory of Open Access Journals (Sweden)

    Toto Jean-Claude

    2010-05-01

    Full Text Available Abstract Background Highland areas of Africa are mostly malaria hypoendemic, due to climate which is not appropriate for anophelines development and their reproductive fitness. In view of designing a malaria control strategy in Western Cameroon highlands, baseline data on anopheline species bionomics were collected. Methods Longitudinal entomological surveys were conducted in three localities at different altitudinal levels. Mosquitoes were captured when landing on human volunteers and by pyrethrum spray catches. Sampled Anopheles were tested for the presence of Plasmodium circumsporozoite proteins and their blood meal origin with ELISA. Entomological parameters of malaria epidemiology were assessed using Mac Donald's formula. Results Anopheline species diversity and density decreased globally from lowland to highland. The most aggressive species along the altitudinal transect was Anopheles gambiae s.s. of S molecular form, followed in the lowland and on the plateau by An. funestus, but uphill by An. hancocki. An. gambiae and An. ziemanni exhibited similar seasonal biting patterns at the different levels, whereas different features were observed for An. funestus. Only indoor resting species could be captured uphill; it is therefore likely that endophilic behaviour is necessary for anophelines to climb above a certain threshold. Of the ten species collected along the transect, only An. gambiae and An. funestus were responsible for malaria transmission, with entomological inoculation rates (EIR of 90.5, 62.8 and zero infective bites/human/year in the lowland, on the plateau and uphill respectively. The duration of gonotrophic cycle was consistently one day shorter for An. gambiae as compared to An. funestus at equal altitude. Altitudinal climate variations had no effect on the survivorship and the subsequent life expectancy of the adult stage of these malaria vectors, but most probably on aquatic stages. On the contrary increasing altitude

  9. Nutrients and bioactive compounds content of Baillonella toxisperma, Trichoscypha abut and Pentaclethra macrophylla from Cameroon.

    Science.gov (United States)

    Fungo, Robert; Muyonga, John; Kaaya, Archileo; Okia, Clement; Tieguhong, Juius C; Baidu-Forson, Jojo J

    2015-07-01

    Baillonella toxisperma, Pentaclethra macrophylla and Trichoscypha abut are important foods for communities living around forests in Cameroon. Information on the nutritional value and bioactive content of these foods is required to establish their contribution to the nutrition and health of the communities. Samples of the three foods were obtained from four villages in east and three villages in south Cameroon. The foods were analyzed for proximate composition, minerals and bioactive content using standard chemical analysis methods. T. abut was found to be an excellent source of bioactive compounds; flavonoids (306 mg/100 g), polyphenols (947 mg/100 g), proanthocyanins (61.2 mg/100 g), vitamin C (80.05 mg/100 g), and total oxalates (0.6 mg/100 g). P. macrophylla was found to be a rich source of total fat (38.71%), protein (15.82%) and total fiber (17.10%) and some bioactive compounds; vitamin E (19.4 mg/100 g) and proanthocyanins (65.0 mg/100 g). B. toxisperma, was found to have high content of carbohydrates (89.6%), potassium (27.5 mg/100 g) and calcium (37.5 mg/100 g). Flavonoids, polyphenols, vitamins C and E are the main bioactive compounds in these forest foods. The daily consumption of some of these fruits may coffer protection against some ailments and oxidative stress. Approximately 200 g of either B. toxisperma or P. macrophylla, can supply 100% iron and zinc RDAs for children aged 1-3 years, while 300 g of the two forest foods can supply about 85% iron and zinc RDAs for non-pregnant non-lactating women. The three foods provide 100% daily vitamins C and E requirements for both adults and children. The results of this study show that Baillonella toxisperma, Pentaclethra macrophylla and Trichoscypha abut can considerably contribute towards the human nutrient requirements. These forest foods also contain substantial levels of health promoting phytochemicals notably flavonoids, polyphenols, vitamins C and E. These foods therefore have

  10. Wind energy potential assessment of Cameroon's coastal regions for the installation of an onshore wind farm.

    Science.gov (United States)

    Arreyndip, Nkongho Ayuketang; Joseph, Ebobenow; David, Afungchui

    2016-11-01

    For the future installation of a wind farm in Cameroon, the wind energy potentials of three of Cameroon's coastal cities (Kribi, Douala and Limbe) are assessed using NASA average monthly wind data for 31 years (1983-2013) and compared through Weibull statistics. The Weibull parameters are estimated by the method of maximum likelihood, the mean power densities, the maximum energy carrying wind speeds and the most probable wind speeds are also calculated and compared over these three cities. Finally, the cumulative wind speed distributions over the wet and dry seasons are also analyzed. The results show that the shape and scale parameters for Kribi, Douala and Limbe are 2.9 and 2.8, 3.9 and 1.8 and 3.08 and 2.58, respectively. The mean power densities through Weibull analysis for Kribi, Douala and Limbe are 33.7 W/m2, 8.0 W/m2 and 25.42 W/m2, respectively. Kribi's most probable wind speed and maximum energy carrying wind speed was found to be 2.42 m/s and 3.35 m/s, 2.27 m/s and 3.03 m/s for Limbe and 1.67 m/s and 2.0 m/s for Douala, respectively. Analysis of the wind speed and hence power distribution over the wet and dry seasons shows that in the wet season, August is the windiest month for Douala and Limbe while September is the windiest month for Kribi while in the dry season, March is the windiest month for Douala and Limbe while February is the windiest month for Kribi. In terms of mean power density, most probable wind speed and wind speed carrying maximum energy, Kribi shows to be the best site for the installation of a wind farm. Generally, the wind speeds at all three locations seem quite low, average wind speeds of all the three studied locations fall below 4.0m/s which is far below the cut-in wind speed of many modern wind turbines. However we recommend the use of low cut-in speed wind turbines like the Savonius for stand alone low energy needs.

  11. Venus volcanism - Classification of volcanic features and structures, associations, and global distribution from Magellan data

    Science.gov (United States)

    Head, James W.; Crumpler, L. S.; Aubele, Jayne C.; Guest, John E.; Saunders, R. S.

    1992-01-01

    A classification and documentation of the range of morphologic features and structures of volcanic origin on Venus, their size distribution, and their global distribution and associations are presented based on a preliminary analysis of Magellan data. Some of the major questions about volcanism on Venus are addressed.

  12. Numerical modeling of volcanic arc development

    Science.gov (United States)

    Gerya, T.; Gorczyk, W.; Nikolaeva, K.

    2007-05-01

    We have created a new coupled geochemical-petrological-thermomechanical numerical model of subduction associated with volcanic arc development. The model includes spontaneous slab bending, subducted crust dehydration, aqueous fluid transport, mantle wedge melting and melt extraction resulting in crustal growth. Two major volcanic arc settings are modeled so far: active continental margins, and intraoceanic subduction. In case of Pacific-type continental margin two fundamentally different regimes of melt productivity are observed in numerical experiments which are in line with natural observations: (1) During continuous convergence with coupled plates highest amounts of melts are formed immediately after the initiation of subduction and then decrease rapidly with time due to the steepening of the slab inclination angle precluding formation of partially molten mantle wedge plumes; (2) During subduction associated with slab delamination and trench retreat resulting in the formation of a pronounced back arc basin with a spreading center in the middle melt production increases with time due to shallowing/stabilization of slab inclination associated with upward asthenospheric mantle flow toward the extension region facilitating propagation of hydrous partially molten plumes from the slab. In case of spontaneous nucleation of retreating oceanic subduction two scenarios of tecono-magmatic evolution are distinguished: (1) decay and, ultimately, the cessation of subduction and related magmatic activity, (2) increase in subduction rate (to up to ~12 cm/yr) and stabilization of subduction and magmatic arc growth. In the first case the duration of subduction correlates positively with the intensity of melt extraction: the period of continued subduction increases from 15,4 Myrs to 47,6 Myrs with the increase of melt extraction threshold from 1% to 9%. In scenario (1) the magmatic arc crust includes large amounts of rocks formed by melting of subducted crust atop the thermally

  13. Volcanic Alert System (VAS) developed during the (2011-2013) El Hierro (Canary Islands) volcanic process

    Science.gov (United States)

    Ortiz, Ramon; Berrocoso, Manuel; Marrero, Jose Manuel; Fernandez-Ros, Alberto; Prates, Gonçalo; De la Cruz-Reyna, Servando; Garcia, Alicia

    2014-05-01

    In volcanic areas with long repose periods (as El Hierro), recently installed monitoring networks offer no instrumental record of past eruptions nor experience in handling a volcanic crisis. Both conditions, uncertainty and inexperience, contribute to make the communication of hazard more difficult. In fact, in the initial phases of the unrest at El Hierro, the perception of volcanic risk was somewhat distorted, as even relatively low volcanic hazards caused a high political impact. The need of a Volcanic Alert System became then evident. In general, the Volcanic Alert System is comprised of the monitoring network, the software tools for the analysis of the observables, the management of the Volcanic Activity Level, and the assessment of the threat. The Volcanic Alert System presented here places special emphasis on phenomena associated to moderate eruptions, as well as on volcano-tectonic earthquakes and landslides, which in some cases, as in El Hierro, may be more destructive than an eruption itself. As part of the Volcanic Alert System, we introduce here the Volcanic Activity Level which continuously applies a routine analysis of monitoring data (particularly seismic and deformation data) to detect data trend changes or monitoring network failures. The data trend changes are quantified according to the Failure Forecast Method (FFM). When data changes and/or malfunctions are detected, by an automated watchdog, warnings are automatically issued to the Monitoring Scientific Team. Changes in the data patterns are then translated by the Monitoring Scientific Team into a simple Volcanic Activity Level, that is easy to use and understand by the scientists and technicians in charge for the technical management of the unrest. The main feature of the Volcanic Activity Level is its objectivity, as it does not depend on expert opinions, which are left to the Scientific Committee, and its capabilities for early detection of precursors. As a consequence of the El Hierro

  14. Treatment failure in a typhoid patient infected with nalidixic acid resistant S. enterica serovar Typhi with reduced susceptibility to Ciprofloxacin: a case report from Cameroon

    Directory of Open Access Journals (Sweden)

    Asonganyi Etienne DN

    2005-06-01

    Full Text Available Abstract Background Fluoroquinolones or third generation cephalosporins are the drugs of choice for the treatment of typhoid fever. Treatment failure with fluoroquinolones has been reported in Asia and Europe. We report a case of ciprofloxacin treatment failure in typhoid fever in Cameroon. Case presentation A 29-year-old female patient with suspected typhoid fever from Kumba, Cameroon, yielded growth of Salmonella enterica serovar Typhi in blood culture. The isolate was resistant to nalidixic acid but sensitive to ciprofloxacin by disc diffusion test. However, the patient did not respond to treatment with ciprofloxacin, although the isolate was apparently susceptible to ciprofloxacin. Conclusion Treatment failure with ciprofloxacin in our case indicates the presence of nalidixic acid resistant S. enterica serovar Typhi (NARST with reduced susceptibility to ciprofloxacin in Cameroon (Central Africa.

  15. Determinants of HIV-1 drug resistance in treatment-naïve patients and its clinical implications in an antiretroviral treatment program in Cameroon

    Directory of Open Access Journals (Sweden)

    Alexander Zoufaly

    2014-11-01

    Full Text Available Introduction: Facing the rapid scale-up of antiretroviral treatment (ART programs in resource-limited settings, monitoring of treatment outcome is essential in order to timely detect and tackle drawbacks [1]. Methods: In a prospective cohort study, 300 consecutive patients starting first-line ART were enrolled between 2009 and2010 in a large HIV treatment centre in rural Cameroon. Patients were followed up for 12 months. Virologic failure was defined as a VL >1000 cop/mL at month 12. Besides CD4 and viral load (VL analysis, HIV-1 drug resistance testing was performed in patients with VL>1000 copies (c/mL plasma. In those patients and controls, minority HIV-1 drug resistance mutations at baseline, and plasma drug levels were analyzed in order to identify the risk factors for virologic failure. Results: Most enrolled patients (71% were female. At baseline median CD4 cell count was 162/µL (IQR 59-259, median log10 VL was 5.4 (IQR 5.0–5.8 c/mL, and one-third of patients had World Health Organisation (WHO stage 3 or 4; 30 patients died during follow-up. Among all patients who completed follow-up 38/238 had virologic failure. These patients were younger, had lower CD4 cell counts and more often had WHO stage 3 or 4 at baseline compared to patients with VL<1000c/mL. Sixty-three percent of failing patients (24/38 had at least one mutation associated with high-level drug resistance. The M184V mutation was the most frequently detected nucleoside reverse transcriptase inhibitor (NRTI mutation (n=18 followed by TAMs (n=5 and multi-NRTI resistance mutations (n=4. The most commonly observed non-nucleoside reverse-transcriptase inhibitor (NNRTI resistance mutations were K103N (n=10, Y181C (n=7, and G190A (n=6. Drug resistance mutations at baseline were detected in 12/65 (18% patients, in 6 patients with and 6 patients without virological failure (p=0.77. Subtherapeutic NNRTI levels (OR 6.67, 95% CI 1.98–22.43, p<0.002 and poorer adherence (OR 1.54, 95% CI

  16. Role of volcanism in climate and evolution

    Energy Technology Data Exchange (ETDEWEB)

    Axelrod, D.I.

    1981-01-01

    Several major episodes of Tertiary explosive volcanism coincided with sharply lowered temperature as inferred from oxygen-isotope composition of foraminiferal tests in deep-sea cores. At these times, fossil floras in the western interior recorded significant changes. Reductions in taxa that required warmth occurred early in the Paleogene. Later, taxa that demand ample summer rain were reduced during a progressive change reflecting growth of the subtropic high. Other ecosystem changes that appear to have responded to volcanically induced climatic modifications include tachytely in Equidae (12 to 10 m.y. B.P.), rapid evolution of grasses (7 to 5 m.y. B.P.), evolution of marine mammals, and plankton flucuations. Although Lake Cretaceous extinctions commenced as epeiric seas retreated, the pulses of sharply lowered temperature induced by explosive volcanism, together with widespread falls of volcanic ash, may have led to extinction of dinosaurs, ammonites, cycadeoids, and other Cretaceous taxa. earlier, as Pangaea was assembled, Permian extinctions resulted not only from the elimination of oceans, epeiric seas, and shorelines, and the spread of more-continental climates, bu also from the climatic effects of major pulses of global volcanism and Gondwana glaciation.

  17. Volcanic activity: a review for health professionals.

    Science.gov (United States)

    Newhall, C G; Fruchter, J S

    1986-03-01

    Volcanoes erupt magma (molten rock containing variable amounts of solid crystals, dissolved volatiles, and gas bubbles) along with pulverized pre-existing rock (ripped from the walls of the vent and conduit). The resulting volcanic rocks vary in their physical and chemical characteristics, e.g., degree of fragmentation, sizes and shapes of fragments, minerals present, ratio of crystals to glass, and major and trace elements composition. Variability in the properties of magma, and in the relative roles of magmatic volatiles and groundwater in driving an eruption, determine to a great extent the type of an eruption; variability in the type of an eruption in turn influences the physical characteristics and distribution of the eruption products. The principal volcanic hazards are: ash and larger fragments that rain down from an explosion cloud (airfall tephra and ballistic fragments); flows of hot ash, blocks, and gases down the slopes of a volcano (pyroclastic flows); "mudflows" (debris flows); lava flows; and concentrations of volcanic gases in topographic depressions. Progress in volcanology is bringing improved long- and short-range forecasts of volcanic activity, and thus more options for mitigation of hazards. Collaboration between health professionals and volcanologists helps to mitigate health hazards of volcanic activity.

  18. Volcanic ash fuels anomalous plankton bloom in subarctic northeast Pacific

    Science.gov (United States)

    Hamme, Roberta C.; Webley, Peter W.; Crawford, William R.; Whitney, Frank A.; DeGrandpre, Michael D.; Emerson, Steven R.; Eriksen, Charles C.; Giesbrecht, Karina E.; Gower, Jim F. R.; Kavanaugh, Maria T.; Peña, M. Angelica; Sabine, Christopher L.; Batten, Sonia D.; Coogan, Laurence A.; Grundle, Damian S.; Lockwood, Deirdre

    2010-10-01

    Using multiple lines of evidence, we demonstrate that volcanic ash deposition in August 2008 initiated one of the largest phytoplankton blooms observed in the subarctic North Pacific. Unusually widespread transport from a volcanic eruption in the Aleutian Islands, Alaska deposited ash over much of the subarctic NE Pacific, followed by large increases in satellite chlorophyll. Surface ocean pCO2, pH, and fluorescence reveal that the bloom started a few days after ashfall. Ship-based measurements showed increased dominance by diatoms. This evidence points toward fertilization of this normally iron-limited region by ash, a relatively new mechanism proposed for iron supply to the ocean. The observations do not support other possible mechanisms. Extrapolation of the pCO2 data to the area of the bloom suggests a modest ˜0.01 Pg carbon export from this event, implying that even large-scale iron fertilization at an optimum time of year is not very efficient at sequestering atmospheric CO2.

  19. [Epidemiologic study of dracunculosis in the Podokwos of the Mandara mountains (northern Cameroon)].

    Science.gov (United States)

    Issoufa, H; Monekosso, G; Ripert, C

    1979-01-01

    The purpose of the present work is the study of the epidemiological aspects of dracontiasis in an endemic area in Cameroon. The study was undertaken in the central Podokwo settlement in Mora subdivision. It is a mountainous area with a climate characterized by a long dry season, from October to mid-May, and a short rainy season. Two seasonal, streams run across the settlement. The water supply of the community is ensured throughout the year by two well built wells. During the rainy season, shallow unprotected wells are the water sources of about 80% of the inhabitants. Among the 944 subjects studied in our sample, 251 had the disease, corresponding to a prevalence of 26 6%. There is no significant difference between both sexes in the prevalence of the disease in our study. The age group 13-26 years is most affected. The worm load varies from 1 to 5, averagely 1.5. As to the localization of the worms in the body, in 92.7% of cases the worms is located in the lower limbs, the feet alone representing up to 46.8%. Less common sites of localization are the head, the breast, the external genitalia. The maximum rate of infestation is observed between August and September. Desinfection of wells with chemicals would be recommended during this period of time.

  20. An Ethnographic Study of Diabetes: Implications for the Application of Patient Centred Care in Cameroon

    Directory of Open Access Journals (Sweden)

    Paschal Kum Awah

    2014-01-01

    Full Text Available Participant observation was conducted to explore the understanding of diabetes and examine the implications of these understandings for providing effective patient centered care in Cameroon. Ethnographic techniques—content and thematic analysis—were used to analyze the data collected from diverse techniques. Most participants distinguished “natural,” “supernatural,” and “man-made” causes of diabetes. Such aetiologies guided the behaviour and approaches adopted for treatment and helped explain why biomedical and traditional healing frameworks could so readily be used in tandem. Clinical encounters are often only one small part of the diabetes care process, alongside recourse to traditional medicine. With rituals, agents causing diabetes are apparently more convincingly explained as powerful reinforcement and a cure promised in traditional medicine. Though it seems “irrational” and dangerous to clinics when patients alternate between therapeutic regimes or pursue both simultaneously, it seems perfectly rational and beneficial to patients and beyond. So long as biomedical practitioners fail to recognize that their patients will probably also have recourse to traditional medicine, they and their services may compound the problems they face for patients to discuss openly how they have been managing their condition.

  1. Characterization of Doayo and Kapsiki taurine cattle breeds of Cameroon in their natural environment.

    Science.gov (United States)

    Ebangi, A Lot; Achukwi, M D; Messine, O; Abba, D

    2011-08-01

    Data were collected on live weight (LW), heart girth (HG), height-at-withers (HW), trunk length (TL), age, sex, and coat color of 207 taurines cattle--122 of the Doayo (Namchi) breed and 85 of the Kapsiki (Kirdi) breed. The animals, aged 1 to 20 years, were selected from 60 herds randomly selected from villages of Poli of Faro and Mokolo of Tsanga, divisions of the North and Far North Regions of Cameroon. The data were analyzed using the SAS program with a linear model, applying standard tests. Results indicated no breed effect (P > 0.05) in the growth trends of LW, HG, HW, and TL. HG and TL were highly significantly (P 0.05) significantly. The breeds attained maturity as from 4 years. In the absence of breed effect (P > 0.05), a single regression equation was established for the estimation of live weight as thus LW = -244.42 (±22.57) kg + 2.49 (±0.23) HG + 1.04 (±0.25) TL, with HG contributing up to 70% of total variation and TL, 2%. This equation could be used to develop a measuring band useful in the rural environment for commercial and clinical veterinary purposes.

  2. Description of a new bat species of the tribe Scotonycterini (Chiroptera, Pteropodidae) from Southwestern Cameroon.

    Science.gov (United States)

    Hassanin, Alexandre

    2014-02-01

    The tribe Scotonycterini is currently composed of three fruit bat species of the family Pteropodidae (Mammalia, Chiroptera) characterized by white fur patches on the head, specifically around the nose and behind the eyes: Scotonycteris zenkeri, S. ophiodon and Casinycteris argynnis. Herein a new species is described, Casinycteris campomaanensis sp. nov., based on female specimen collected in 2007 near the village Nkoélon-Mvini close to the Campo-Ma'an National Park, southwestern Cameroon. It is readily distinguished from the three other species of Scotonycterini by its body size and craniodental characteristics. Molecular analyses based on the complete mitochondrial cytochrome b gene indicate that the new species is the sister-group to C. argynnis and that the holotype of S. ophiodon is more closely related to Casinycteris than to S. zenkeri, rendering the genus Scotonycteris paraphyletic. Based on these results, morphological characters within the tribe Scotonycterini were reassessed and a new classification is proposed, in which the new species and S. ophiodon are placed in the genus Casinycteris.

  3. Identification of trypanosomes in wild animals from Southern Cameroon using the polymerase chain reaction (PCR

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    Herder S.

    2002-12-01

    Full Text Available One possible explanation of the maintenance of many historical foci of sleeping sickness in Central Africa could be the existence of a wild animal reservoir. In this study, PCR was used to detect the different trypanosome species present in wild animal captured by hunters in the southern forest belt of Cameroon (Bipindi. Trypanosomes were also detected by a parasitological method (Quantitative buffy coat : QBC. Parasite could not be isolated in culture medium (Kit for in vitro isolation : KIVI. Specific primers of T. brucei s.l., T. congolense forest type, T. congolense savannah type, T. vivax, T. simiae and T. b. gambiense group 1 were used to identify parasites in the blood of 164 animals belonging to 24 different species including ungulates, rodents, pangolins, carnivores, reptiles and primates. Of the 24 studied species, eight were carrying T. b. gambiense group 1. Those parasites pathogenic to man were found in monkeys (Cercocebus torquatus and Cercopithecus nictitans, in ungulates (Cephalophus dorsalis and C. monticola, in carnivores (Nandinia binotata and Genetta servalina and in rodents (Cricetomys gambianus and Atherurus africanus. 13 species (54 % were carrying T. brucei s.l. identified as non-gambiense group 1.

  4. [Anopheles gambiae, major malaria vector in Logbessou, a peri-urban area of Douala (Cameroon)].

    Science.gov (United States)

    Akono, P Ntonga; Tonga, C; Mbida, J A Mbida; Hondt, O E Ngo; Ambene, P Awono; Ndo, C; Magne, G Tamdem; Peka, M F; Ngaha, R; Lehman, L G

    2015-12-01

    An entomological survey was carried out from August to November 2013, in order to determine the vector system of a building site for social housing in a coastal periurban district of Douala (Cameroon). Mosquito larvae were collected and adult endophilic mosquitoes captured on volunteers, for a total sample of 4897 mosquitoes. Morpho-taxonomic techniques alongside molecular techniques enabled the identification of 4 species, all aggressive to humans: Cx. pipiens (22.3%), Ae. albopictus (0.3%), An. coluzzii and An. gambiae (77.4%). The overall average biting rate recorded was 41.73 bites/person/night (b/p/n). An. gambiae s.l. represents 90.82% of this aggressive fauna, followed by Cx. pipiens (8.58%) and Ae. albopictus (0.6%). The detection of CSP showed that An. gambiae was responsible for 100% of P. falciparum transmission. The overall mean Entomological Inoculation Rate (EIR) was 3.94 ib/p/n. Female An. gambiae mortality rates were 14.47%, 82.5% and 100% respectively with DDT, permethrin and deltamethrin. The proliferation of An. gambiae in this area during raining season, at the detriment of An. coluzzii Coetze & Wilkerson and An. melas Theobald known to be major malaria vectors in island and coastal areas of Africa, may owe to the forest that still colonises this coastal peri-urban locality. Residents should therefore make use of deltamethrin based protective measures.

  5. Interhousehold variability and its effects on seed circulation networks: a case study from northern Cameroon

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    Jean Wencélius

    2016-03-01

    Full Text Available We present a detailed ethnographic case study of sorghum seed acquisitions in a smallholder farming society in northern Cameroon. The effects of variability in household demographics and socioeconomic status on observed patterns of seed provisioning are explored alongside other variables such as age and gender. Our data set comprised 223 seed acquisition events. Independence tests (Pearson's chi-square and Fisher's exact tests were carried out to test for significant dependencies between individual- or household-level characteristics and properties of seed acquisition events (categories of seed source, social relationship of exchange, and type of landrace. Results indicate that wealth is a structuring factor of the local seed circulation network in as much as it is highly correlated with household composition and size. Members from wealthy households benefit from a more diverse set of seed sources. Their greater number of coresidents and the importance of intrahousehold dynamics of seed transactions also play a role in making wealthy farmers more seed secure than others. The methodological implications of our findings indicate that when documenting seed exchange networks, the collection of data through a single informant or the undertaking of social network analyses at the household level may induce important biases.

  6. Tropical chemical weathering of a garnet rich micaschist in the rainforest zone of Cameroon

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    Désiré Tsozué

    2017-01-01

    Full Text Available Soils developed on garnet-rich micaschist in the Southern Cameroon plateau were investigated. Morphologically, two weathering materials constituted the study profile, fine earth and nodules. Each material has a singular evolution from the coarse saprolite to the upper set of clayey and loose horizons. There is Al2O3 enrichment in the fine earth concomitantly to Fe2O3, Na2O and K2O enrichment in nodules in major element–Al2O3 variation diagrams. A–CN–K and A–CNK–FM diagrams show a progressive depletion of Al in nodules concomitantly to an enrichment of this element in the fine earth. Three pedogenetic processes emerge from the evolution of weathering products. There is a ferruginization process whose importance increases from the coarse saprolite to the upper set of clayey and loose horizons, giving rise to the formation of dense nodules composed of hematite, goethite and gibbsite. This ferruginization occurs concomitantly with a desaluminization process, which causes Al2O3 depletion in nodules. These nodules are formed by the process of induration where the hydrated amorphous hydroxide and oxides are dehydrated to their crystalline oxide form, due to condensation. In addition, there is aluminization, which occurs in the fine earth, leading to the development of a red clayey material composed of kaolinite and gibbsite.

  7. Novel highly divergent reassortant bat rotaviruses in Cameroon, without evidence of zoonosis

    Science.gov (United States)

    Yinda, Claude Kwe; Zeller, Mark; Conceição-Neto, Nádia; Maes, Piet; Deboutte, Ward; Beller, Leen; Heylen, Elisabeth; Ghogomu, Stephen Mbigha; Van Ranst, Marc; Matthijnssens, Jelle

    2016-01-01

    Bats are an important reservoir for zoonotic viruses. To date, only three RVA strains have been reported in bats in Kenya and China. In the current study we investigated the genetic diversity of RVAs in fecal samples from 87 straw-colored fruit bats living in close contact with humans in Cameroon using viral metagenomics. Five (near) complete RVA genomes were obtained. A single RVA strain showed a partial relationship with the Kenyan bat RVA strain, whereas the other strains were completely novel. Only the VP7 and VP4 genes showed significant variability, indicating the occurrence of frequent reassortment events. Comparing these bat RVA strains with currently used human RVA screening primers indicated that most of the novel VP7 and VP4 segments would not be detected in routine epidemiological screening studies. Therefore, novel consensus screening primers were developed and used to screen samples from infants with gastroenteritis living in close proximity with the studied bat population. Although RVA infections were identified in 36% of the infants, there was no evidence of zoonosis. This study identified multiple novel bat RVA strains, but further epidemiological studies in humans will have to assess if these viruses have the potential to cause gastroenteritis in humans. PMID:27666390

  8. In Cameroon, a female-centred organization works to conquer the poverty of rural women.

    Science.gov (United States)

    Fonkem, R N

    1999-01-01

    This is a discussion of the work of the Rural Women Development Council for poor rural women in Cameroon. The concept of absolute poverty involves the measurement of the quantity and quality of necessities required to maintain the average well-being of an individual or group of individuals. The standards are considered to be relative to a particular time and place. Subjective poverty is a state of acceptance by the person who is poor that he or she is poor; it is independent of the perspective of onlookers. Income levels vary resulting, and as a result, poverty exists. Under those premises, the Rural Women Development Council (RWDC) is helping to alleviate poverty in rural women through microcredit schemes. Over 200 women have engaged in farming and small trades. Increased equity, enhanced opportunity, peace and security, participation and sustainable future, in addition to increased income, help to defeat poverty. Strategies for eradicating poverty include enhancing the ability of local communities to adapt to stress, overcome emergencies and improve long-term productivity. The RWDC have observed that loanees are today economically above other rural women.

  9. Notes on the blood-feeding behavior of Aedes albopictus (Diptera: Culicidae in Cameroon

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    Kamgang Basile

    2012-03-01

    Full Text Available Abstract Background The invasive mosquito Aedes albopictus is often considered a poor vector of human pathogens, owing to its catholic feeding behavior. However, it was recently incriminated as a major vector in several Chikungunya epidemics, outside of its native range. Here we assessed two key elements of feeding behavior by Ae. albopictus females in Yaoundé, Cameroon, Central Africa. Host preference was explored and the human-biting activity of females was monitored over 24 h to determine periods of maximum bite exposure. Findings Analysis of ingested blood in outdoor-resting females showed that Ae. albopictus preferentially fed on humans rather than on available domestic animals (95% of the blood meals contained human blood. Our results further showed that Ae. albopictus is a day-biting species in Yaoundé, with a main peak of activity in the late afternoon. Conclusion This is the first report on the feeding behavior of Ae. albopictus in Central Africa. The species is highly aggressive to humans and might therefore be involved in human-human virus transmission in this setting.

  10. Treatment of Diabetes and/or Hypertension Using Medicinal Plants in Cameroon.

    Science.gov (United States)

    Tsabang, N; Yedjou, C G; Tsambang, Lwd; Tchinda, A T; Donfagsiteli, N; Agbor, G A; Tchounwou, Pbb; Nkongmeneck, B A

    Medicinal plants have served as valuable starting materials for drug development in both developing and developed countries. Today, more than 80% of the people living in Africa were depended on medicinal plants based medicines to satisfy their healthcare needs. The main goal of the present study was to collect and document information on herbal remedies traditionally used for the treatment of diabetes and/or hypertension in Cameroon. To reach this objective, data were collected from 328 patients who have been diagnosed at least once by a physician as diabetics and/or hypertension patients. One hundred and eighty two (182) among them took for a period of 10 days different varieties of medicinal plants which were prepared in form of decoction, maceration and infusion and administered orally twice or three times daily. As result, 70% of patients who used plants were relieved at the end of the treatment. Thirty-three plants have been recorded and documented for the treatment of diabetes and/or hypertension. The results of this study can stimulate a sustainable development by providing the basis for drugs discovery and by documenting biodiversity for long time exploitation.

  11. Sustaining mother tongue medium education: An inter-community self-help framework in Cameroon

    Science.gov (United States)

    Chiatoh, Blasius A.

    2011-12-01

    Advocating mother tongue education implies recognising the centrality of linguistic and cultural diversity in quality and accessible education planning and delivery. In minority linguistic settings, this need becomes particularly urgent. Decades of exclusive promotion of foreign languages have rendered the educational system incapable of guaranteeing maximum quality, accessibility and equity. Also, due to long periods of marginalisation and disempowerment, most indigenous communities are unable to undertake viable self-reliant educational initiatives. As a result, planning and management of education is not adapted to the needs and realities of target populations. What such an educational approach has succeeded in achieving is to cultivate a culture of near-total dependence and consumerism. In minority language situations where mother tongue education is still primarily in the hands of private institutions and individuals, successful planning also means influencing the perceptions and attitudes of indigenous people and systematically integrating them into the educational process. This paper discusses grass-roots mother tongue education in Cameroon. It focuses on the inter-community self-help initiative as a local response framework and argues that this initiative is a strong indication of the desire of communities to learn and promote learning in their own languages.

  12. Risk factors for buruli ulcer: a case control study in Cameroon.

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    Régis Pouillot

    Full Text Available BACKGROUND: Buruli ulcer is an infectious disease involving the skin, caused by Mycobacterium ulcerans. This disease is associated with areas where the water is slow-flowing or stagnant. However, the exact mechanism of transmission of the bacillus and the development of the disease through human activities is unknown. METHODOLOGY/PRINCIPAL FINDINGS: A case-control study to identify Buruli ulcer risk factors in Cameroon compared case-patients with community-matched controls on one hand and family-matched controls on the other hand. Risk factors identified by the community-matched study (including 163 pairs were: having a low level of education, swamp wading, wearing short, lower-body clothing while farming, living near a cocoa plantation or woods, using adhesive bandages when hurt, and using mosquito coils. Protective factors were: using bed nets, washing clothes, and using leaves as traditional treatment or rubbing alcohol when hurt. The family-matched study (including 118 pairs corroborated the significance of education level, use of bed nets, and treatment with leaves. CONCLUSIONS/SIGNIFICANCE: Covering limbs during farming activities is confirmed as a protective factor guarding against Buruli ulcer disease, but newly identified factors including wound treatment and use of bed nets may provide new insight into the unknown mode of transmission of M. ulcerans or the development of the disease.

  13. Indications for Surgical Removal of the Eye in Rural Areas in Cameroon

    Science.gov (United States)

    Kagmeni, Giles; Noche, Christelle Domngang; Nguefack-Tsague, Georges; Wiedemann, Peter

    2014-01-01

    OBJECTIVE To determine the main clinical indications for surgical removal of the eye in rural areas in Cameroon. DESIGN Retrospective non-comparative case series. PARTICIPANTS A total of 253 patients presenting to the Manna eye clinic Nkongsamba who underwent destructive eye surgery (DES) between January 2006 and December 2010 were reviewed. MAIN OUTCOME MEASURE Age, gender, occupation, prior medication, visual acuity, operation indications, and type of operation. RESULTS There were 58.10% (n = 147) men and 41.90% (n = 106) women. Median age was 29 years (interquartile range: 14–69 years); age ranged from 10 to 88 years. A total of 67.19% (n = 170) of participants were farmers and lived in rural zones. In all, 79.05% (n = 200) confessed to have trying a medication before the presentation. Surgical indications included infective causes (perforated corneal ulcer 33.20% (n = 84) and endophthalmitis 18.20% (n = 46)), trauma 17.40% (n = 44), painful blind eyes 11.50% (n = 29), malignancy 10.70% (n = 27), and others 9.10% (n = 23). CONCLUSION The most common causes of DES in this series could be avoided. Therefore, preventive measures including extensive health education of the public and traditional healers on the risks linked to the use of traditional medicines in ophthalmology and the late presentation of eye disease, quality control of the campaigns that offer free cataract operations in the country. PMID:24940088

  14. PROSTATIC ILLNESSES: EPIDEMIOLOGY AND TREATMENT WITH MEDICINAL PLANTS AT MAROUA (CAMEROON

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    Noumi E

    2011-03-01

    Full Text Available Three fieldworks were done at Maroua area in the Northern Cameroon to evaluate the epidemiology and the prophylaxis of prostatic illnesses, in 2008-2010. Data from the central Hospital of Maroua permitted us to appreciate the epidemiology. Interviews on 22 patients showed the risk factors for the apparition of prostatic illnesses and discussion with 27 phytotherapists indicated the treatments as done in the study area.Surgical intervention of Urogenital tumors related to prostatic illnesses occupy a preponderant place (51% in the surgery Service of the regional Hospital of Maroua. The patients prefer to go to traditional Doctors for treatment although there, the diagnoses by symptoms are approximate. Four plants are the more used by the traditional healers in the treatment of the prostatic illnesses: Azadirachta indica, Moringa oleifera, Sanseviera senegambica and Tamarindus indica; and 5 are new in the Cameroonian ethnobotany literature: Hyparrhenia nyassae, Hyphaene thebaica, Prosopis africana, Marsdenia sylvestri and Thelepogon elegans. The rate of monospecific recipe is lower (2/18 with respect to bispecific (12/18 or trispecific ones. The population of Maroua, both patients and phytotherapists, need some information on the feeding, the type of foods and the temperament of the prostate.

  15. History of partnership between agro-industries and oil palm smallholders in Cameroon

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    Nkongho Raymond N.

    2015-05-01

    Full Text Available The present article explores the origin and changes in partnership agreements established between agro-industries and oil palm smallholders in Cameroon. The different forms of partnership which have existed over the years in the oil palm sector until now are assessed, notably the FONADER-sponsored smallholder scheme (1978 to 1991 and more recently the Afriland First Bank sponsored villagisation project of Socapalm Eseka (2007/2008 to present. Special attention is given to the factors and conditions that have influenced the outcomes of these partnerships, specifically the failure of the FONADER-sponsored smallholder scheme. The authors conclude that with the current absence of steady support from the government to oil palm smallholders, especially after the implementation of the structural adjustment plans, private partnership schemes between agro-industries and oil palm smallholders could be highly profitable for both stakeholders. Such partnerships can foster social cohesion and limit further encroachment of agro-industries into the primary forest, provided such partnership agreements are carefully planned and adequately implemented.

  16. Nutritional Composition of Five Varieties of Pap Commonly Consumed in Maroua (Far-North, Cameroon

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    Ponka Roger

    2015-09-01

    Full Text Available The aim of this study was to determine the nutritional composition of five varieties of pap (cereal product commonly consumed in Maroua, city of the Far-North Region of Cameroon. The proximate composition (moisture, ash, protein, lipid, and crude fibre was determined by standard AOAC methods. Minerals (calcium, magnesium, sodium, potassium, iron, zinc, copper and manganese were determined by atomic absorption spectrophotometry and phosphorus was determined colorimetrically. Amino acid composition was determined by ion-exchange chromatography. All the pap varieties had a very high carbohydrate content (79.47-85.29 g/100 g dry matter. Appreciable levels of phosphorus and potassium were recorded in all the pap varieties (137.5-231.0 mg/100 g dry matter and 198.20-322.22 mg/100 g dry matter, respectively. Consumption of each pap (100 g by children 1-2 year old would meet 9.86-17.46% and 0.08-19.51% of their daily recommended intake respectively for protein and minerals. Leucine and glutamic acid were the most abundant essential amino acids and non-essential amino acids respectively in the pap. Essential amino acids in most of the pap samples met the recommended children requirement of the FAO/WHO/UNU for 1-2 year old children except methionine+cysteine and lysine.

  17. Neighborhood diversity of potentially pathogenic bacteria in drinking water from the city of Maroua, Cameroon.

    Science.gov (United States)

    Healy-Profitós, Jessica; Lee, Seungjun; Mouhaman, Arabi; Garabed, Rebecca; Moritz, Mark; Piperata, Barbara; Lee, Jiyoung

    2016-06-01

    This study examined the spatial variation of potential gastrointestinal pathogens within drinking water sources and home storage containers in four neighborhoods in Maroua, Cameroon. Samples were collected from source (n = 28) and home containers (n = 60) in each study neighborhood. Pathogen contamination was assessed using quantitative polymerase chain reaction, targeting Campylobacter spp., Shiga toxin producing Escherichia coli (virulence genes, stx1 and stx2), and Salmonella spp. Microbial source tracking (MST) targeted three different host-specific markers: HF183 (human), Rum2Bac (ruminant) and GFD (poultry) to identify contamination sources. Staphylococcus aureus and the tetracycline-resistance gene (tetQ) were assessed to measure human hand contact and presence of antibiotic-resistant bacteria. Pathogen/MST levels were compared statistically and spatially, and neighborhood variation was compared with previously collected demographic information. All the test fecal markers and pathogens (except Arcobacter) were detected in home and source samples. Two neighborhoods tested positive for most pathogens/MST while the others only tested positive for one or two. Spatial variation of pathogens/MST existed between sources, storage containers, and neighborhoods. Differing population density and ethno-economic characteristics could potentially explain variation. Future research should explore the influence of demographic and ethno-economic factors on water quality during microbial risk assessments in urban Africa.

  18. Human physique and sexual attractiveness: sexual preferences of men and women in Bakossiland, Cameroon.

    Science.gov (United States)

    Dixson, Barnaby J; Dixson, Alan F; Morgan, Bethan; Anderson, Matthew J

    2007-06-01

    Men and women living in a rural community in Bakossiland, Cameroon were asked to rate the attractiveness of images of male or female figures manipulated to vary in somatotype, waist-to-hip ratio (WHR), secondary sexual traits, and other features. In Study 1, women rated mesomorphic (muscular) and average male somatotypes as most attractive, followed by ectomorphic (slim) and endomorphic (heavily built) figures. In Study 2, amount and distribution of masculine trunk (chest and abdominal) hair was altered progressively in a series of front-posed male figures. A significant preference for one of these images was found, but the most hirsute figure was not judged as most attractive. Study 3 assessed attractiveness of front-posed male figures which varied only in length of the non-erect penis. Extremes of penile size (smallest and largest of five images) were rated as significantly less attractive than three intermediate sizes. In Study 4, Bakossi men rated the attractiveness of back-posed female images varying in WHR (from 0.5-1.0). The 0.8 WHR figure was rated markedly more attractive than others. Study 5 rated the attractiveness of female skin color. Men expressed no consistent preference for either lighter or darker female figures. These results are the first of their kind reported for a Central African community and provide a useful cross-cultural perspective to published accounts on sexual selection, human morphology and attractiveness in the U.S., Europe, and elsewhere.

  19. Regulation of business activities of petroleum contractors in Cameroon, Congo, Gabon, and Ivory Coast

    Energy Technology Data Exchange (ETDEWEB)

    Frilet, M.; Newman, J.

    1982-03-01

    Foreign companies engaging in business in Cameroon, Congo, Gabon, and Ivory Coast are subject to a broad range of regulations. This article deals only with those aspects of the regulations that are most important to petroleum contractors intending to engage in business in these countries. The regulator scheme actually applicable in a given case will depend on the legal structure through which a corporation operates. An American corporation may envisage engaging in business on a long-term basis through a local subsidiary or branch. On the other hand, it may wish only to perform temporary activities pursuant to one or more fixed-duration contracts with petroleum companies operating in one of countries. Each of these situations is dealt with. Common features of each area of regulation were described and the differences in regulations were presented. These topics were included: exchange control regulation, corporate forms of business association, authorization to engage in business, requirement of government or local participation in capital, investment code incentives, labor law requirements, taxation of corporations, taxation of profits, taxation of income from movable capital, taxation of amounts paid abroad as technical assistance fees, royalties and similar compensation, turnover taxes, payroll taxes, taxation of business performed without forming a local company or branch, taxation of employees and Social Security contributions. (DP)

  20. Natural enemies of lepidopterous borers on maize and elephant grass in the forest zone of Cameroon.

    Science.gov (United States)

    Ndemah, R; Schulthess, F; Poehling, M; Borgemeister, C; Goergen, G

    2001-06-01

    The importance, geographical and temporal distributions of parasitoids of lepidopterous borers on maize and elephant grass, Pennisetum purpureum, were assessed during surveys in farmers' fields in six villages and two on-station trials in the forest zone of Cameroon between 1995 and 1996. The borer species encountered were Busseola fusca (Fuller), Sesamia calamistis Hampson, Eldana saccharina Walker on both host plants, and Mussidia nigrivenella Ragonot on maize only. Busseola fusca was the predominant host accounting for 44-57% and 96% on maize and elephant grass, respectively, followed by E. saccharina on maize with 27-39%. Fifteen hymenopterous, two dipterous and one fungal species were found on these stem and cob-borers. Among those were six pupal, six larval, four egg, one larval-pupal parasitoid and four hyperparasitoids. The scelionid parasitoids Telenomus busseolae Gahan and T. isis Polaszek were found on B. fusca eggs in all locations. During the first season, mean egg parasitism was low and ranged between 3.1% and 27% versus 54-87% during the second season. Species belonging to the Tetrastichus atriclavus Waterston complex were recovered from all four borer species. The majority and most common larval and pupal parasitoid species belonged to the ingress-and-sting guild. Larval and pupal parasitism were very erratic and on more than 50% of the sampling occasions no parasitoids were recovered. Parasitoid diversity was higher on elephant grass than maize.

  1. Muddying the Waters: A New Area of Concern for Drinking Water Contamination in Cameroon

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    Jessica M. Healy Profitós

    2014-11-01

    Full Text Available In urban Maroua, Cameroon, improved drinking water sources are available to a large majority of the population, yet this water is frequently distributed through informal distribution systems and stored in home containers (canaries, leaving it vulnerable to contamination. We assessed where contamination occurs within the distribution system, determined potential sources of environmental contamination, and investigated potential pathogens. Gastrointestinal health status (785 individuals was collected via health surveys. Drinking water samples were collected from drinking water sources and canaries. Escherichia coli and total coliform levels were evaluated and molecular detection was performed to measure human-associated faecal marker, HF183; tetracycline-resistance gene, tetQ; Campylobacter spp.; and Staphylococcus aureus. Statistical analyses were performed to evaluate the relationship between microbial contamination and gastrointestinal illness. Canari samples had higher levels of contamination than source samples. HF183 and tetQ were detected in home and source samples. An inverse relationship was found between tetQ and E. coli. Presence of tetQ with lower E. coli levels increased the odds of reported diarrhoeal illness than E. coli levels alone. Further work is warranted to better assess the relationship between antimicrobial-resistant bacteria and other pathogens in micro-ecosystems within canaries and this relationship’s impact on drinking water quality.

  2. Prevalence of Hypertension in HIV/AIDS Patients on Highly Active Antiretroviral Therapy (HAART Compared with HAART-Naive Patients at the Limbe Regional Hospital, Cameroon.

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    Christian Akem Dimala

    Full Text Available Highly active antiretroviral therapy (HAART has greatly reduced the morbidity and mortality of HIV/AIDS patients but has also been associated with increased metabolic complications and cardiovascular diseases. Data on the association between HAART and hypertension (HTN in Africa are scarce.Primarily to compare the prevalence of HTN in HIV/AIDS patients on HAART and HAART-naïve patients in Limbe, Cameroon; and secondarily to assess other socio-demographic and clinical factors associated with HTN in this population.A cross-sectional study was conducted at the Limbe Regional Hospital HIV treatment center between April and June 2013, involving 200 HIV/AIDS patients (100 on first-line HAART regimens for at least 12 months matched by age and sex to 100 HAART-naïve patients. HTN was defined as a systolic blood pressure (BP ≥ 140 mmHg and/or diastolic BP ≥ 90 mmHg.The prevalence of HTN in patients on HAART was twice (38%; 95% CI: 28.5-48.3 that of the HAART-naïve patients (19%; 95% CI, 11.8-28.1, p = 0.003. In multivariate analyses adjusted for age, gender, smoking, family history of HTN, and BMI-defined overweight, HAART was associated with HTN, the adjusted odds ratio of the HAART-treated versus HAART-naïve group was 2.20 (95% CI: 1.07-4.52, p = 0.032. HTN was associated with older age and male gender, in the HAART group and with BMI-defined overweight in the HAART-naïve group.The prevalence of hypertension in HIV/AIDS patients in Limbe stands out to be elevated, higher in patients on HAART compared to those not on treatment. Blood pressure and cardiovascular risk factors should be routinely monitored. Other factors such as diet, weight control and physical exercise should also be considered.

  3. Shallow groundwater from the far north of Cameroon (southern Lake Chad): revisiting a 20 years old survey of hydrochemistry and stable isotopes

    Science.gov (United States)

    Ketchemen-Tandia, Beatrice; Mohammad, Bello; Fouepe, Alain; Ngo Boum, Suzanne; Nlend, Bertil; Garel, Emilie; Celle-Jeanton, Helene; Huneau, Frederic

    2016-04-01

    Two field hydrogeological investigation surveys were conducted in 1992 and 2013 using hydrochemistry and isotope techniques in the far north part of Cameroon which corresponds to the southern part of Lake Chad basin. All of these data relate to groundwater and surface water which were collected at the same places to potentially reveal any temporal variation in the chemical and isotopic characteristics of the water resources. Groundwater show mainly a Ca-HCO3 water type but CaMg-Cl and Na-HCO3 water types can also be found. The groundwater chemistry is resulting from many processes including pure silicate weathering and cation exchange. It is found that the nitrate content after 20 years has increased by an average factor of 6. These high concentrations in nitrate (up to 400 mg/l) are related to local anthropogenic activities and to the very bad conditions of maintaining of wells and boreholes. This pollution is also correlated to the population growth over the past two decades in the region. The isotopic content of groundwater is ranging from -6.87‰ to -0.32‰ for δ18O in 2013 and from -6.03‰ to +0.25‰ in 1992 without noticeable evolution through time. The conventional δD-δ18O diagram indicates that the groundwater has a meteoric origin more or less influenced by evaporation processes. Different processes involving different water sources were highlighted: (i) groundwater which has been affected by evaporation or in communication with evaporated surface waters; (ii) groundwater which is very close to the Global Meteoric Water Line and corresponding to a recent and direct recharge from precipitation; (iii) groundwater which is more depleted corresponding to a mixing between shallow and deep groundwater. This research is partly supported by the RAF7012and RAF7011 project from IAEA.

  4. National volcanic ash operations plan for aviation

    Science.gov (United States)

    ,; ,

    2007-01-01

    The National Aviation Weather Program Strategic Plan (1997) and the National Aviation Weather Initiatives (1999) both identified volcanic ash as a high-priority informational need to aviation services. The risk to aviation from airborne volcanic ash is known and includes degraded engine performance (including flameout), loss of visibility, failure of critical navigational and operational instruments, and, in the worse case, loss of life. The immediate costs for aircraft encountering a dense plume are potentially major—damages up to $80 million have occurred to a single aircraft. Aircraft encountering less dense volcanic ash clouds can incur longer-term costs due to increased maintenance of engines and external surfaces. The overall goal, as stated in the Initiatives, is to eliminate encounters with ash that could degrade the in-flight safety of aircrews and passengers and cause damage to the aircraft. This goal can be accomplished by improving the ability to detect, track, and forecast hazardous ash clouds and to provide adequate warnings to the aviation community on the present and future location of the cloud. To reach this goal, the National Aviation Weather Program established three objectives: (1) prevention of accidental encounters with hazardous clouds; (2) reduction of air traffic delays, diversions, or evasive actions when hazardous clouds are present; and (3) the development of a single, worldwide standard for exchange of information on airborne hazardous materials. To that end, over the last several years, based on numerous documents (including an OFCMsponsored comprehensive study on aviation training and an update of Aviation Weather Programs/Projects), user forums, and two International Conferences on Volcanic Ash and Aviation Safety (1992 and 2004), the Working Group for Volcanic Ash (WG/VA), under the OFCM-sponsored Committee for Aviation Services and Research, developed the National Volcanic Ash Operations Plan for Aviation and Support of the

  5. Marine mesocosm bacterial colonisation of volcanic ash

    Science.gov (United States)

    Witt, Verena; Cimarelli, Corrado; Ayris, Paul; Kueppers, Ulrich; Erpenbeck, Dirk; Dingwell, Donald; Woerheide, Gert

    2015-04-01

    Volcanic eruptions regularly eject large quantities of ash particles into the atmosphere, which can be deposited via fallout into oceanic environments. Such fallout has the potential to alter pH, light and nutrient availability at local scales. Shallow-water coral reef ecosystems - "rainforests of the sea" - are highly sensitive to disturbances, such as ocean acidification, sedimentation and eutrophication. Therefore, wind-delivered volcanic ash may lead to burial and mortality of such reefs. Coral reef ecosystem resilience may depend on pioneer bacterial colonisation of the ash layer, supporting subsequent establishment of the micro- and ultimately the macro-community. However, which bacteria are involved in pioneer colonisation remain unknown. We hypothesize that physico-chemical properties (i.e., morphology, mineralogy) of the ash may dictate bacterial colonisation. The effect of substrate properties on bacterial colonisation was tested by exposing five substrates: i) quartz sand ii) crystalline ash (Sakurajima, Japan) iii) volcanic glass iv) carbonate reef sand and v) calcite sand of similar grain size, in controlled marine coral reef aquaria under low light conditions for six months. Bacterial communities were screened every month by Automated Ribosomal Intergenic Spacer Analysis of the 16S-23S rRNA Internal Transcribed Spacer region. Multivariate statistics revealed discrete groupings of bacterial communities on substrates of volcanic origin (ash and glass) and reef origin (three sands). Analysis of Similarity supported significantly different communities associated with all substrates (p=0.0001), only quartz did not differ from both carbonate and calcite sands. The ash substrate exhibited the most diverse bacterial community with the most substrate-specific bacterial operational taxonomic units. Our findings suggest that bacterial diversity and community composition during colonisation of volcanic ash in a coral reef-like environment is controlled by the

  6. Constraining the onset of flood volcanism in Isle of Skye Lava Field, British Paleogene Volcanic Province

    Science.gov (United States)

    Angkasa, Syahreza; Jerram, Dougal. A.; Svensen, Henrik; Millet, John M.; Taylor, Ross; Planke, Sverre

    2016-04-01

    In order to constrain eruption styles at the onset of flood volcanism, field observations were undertaken on basal sections of the Isle of Skye Lava Field, British Paleogene Volcanic Province. This study investigates three specific sections; Camus Ban, Neist Point and Soay Sound which sample a large area about 1500 km2 and can be used to help explain the variability in palaeo-environments at the onset of flood volcanism. Petrological analysis is coupled with petrophysical lab data and photogrammetry data to create detailed facies models for the different styles of initiating flood basalt volcanism. Photogrammetry is used to create Ortho-rectified 3D models which, along with photomontage images, allow detailed geological observations to be mapped spatially. Petrographic analyses are combined with petrophysical lab data to identify key textural variation, mineral compositions and physical properties of the volcanic rocks emplaced during the initial eruptions. Volcanism initiated with effusive eruptions in either subaerial or subaqueous environments resulting in tuff/hyaloclastite materials or lava flow facies lying directly on the older Mesozoic strata. Volcanic facies indicative of lava-water interactions vary significantly in thickness between different sections suggesting a strong accommodation space control on the style of volcanism. Camus Ban shows hyaloclastite deposits with a thickness of 25m, whereas the Soay Sound area has tuffaceous sediments of under 0.1m in thickness. Subaerial lavas overly these variable deposits in all studied areas. The flood basalt eruptions took place in mixed wet and dry environments with some significant locally developed water bodies (e.g. Camus Ban). More explosive eruptions were promoted in some cases by interaction of lavas with these water bodies and possibly by local interaction with water - saturated sediments. We record key examples of how palaeotopography imparts a primary control on the style of volcanism during the

  7. Volcanic Eruptions and Climate: Outstanding Research Issues

    Science.gov (United States)

    Robock, Alan

    2016-04-01

    Large volcanic eruptions inject sulfur gases into the stratosphere, which convert to sulfate aerosols with an e-folding residence time of about one year. The radiative and chemical effects of this aerosol cloud produce responses in the climate system. Based on observations after major eruptions of the past and experiments with numerical models of the climate system, we understand much about their climatic impact, but there are also a number of unanswered questions. Volcanic eruptions produce global cooling, and are an important natural cause of interannual, interdecadal, and even centennial-scale climate change. One of the most interesting volcanic effects is the "winter warming" of Northern Hemisphere continents following major tropical eruptions. During the winter in the Northern Hemisphere following every large tropical eruption of the past century, surface air temperatures over North America, Europe, and East Asia were warmer than normal, while they were colder over Greenland and the Middle East. This pattern and the coincident atmospheric circulation correspond to the positive phase of the Arctic Oscillation. While this response is observed after recent major eruptions, most state-of-the-art climate models have trouble simulating winter warming. Why? High latitude eruptions in the Northern Hemisphere, while also producing global cooling, do not have the same impact on atmospheric dynamics. Both tropical and high latitude eruptions can weaken the Indian and African summer monsoon, and the effects can be seen in past records of flow in the Nile and Niger Rivers. Since the Mt. Pinatubo eruption in the Philippines in 1991, there have been no large eruptions that affected climate, but the cumulative effects of small eruptions over the past decade have had a small effect on global temperature trends. Some important outstanding research questions include: How much seasonal, annual, and decadal predictability is possible following a large volcanic eruption? Do

  8. Tellurium in active volcanic environments: Preliminary results

    Science.gov (United States)

    Milazzo, Silvia; Calabrese, Sergio; D'Alessandro, Walter; Brusca, Lorenzo; Bellomo, Sergio; Parello, Francesco

    2014-05-01

    Tellurium is a toxic metalloid and, according to the Goldschmidt classification, a chalcophile element. In the last years its commercial importance has considerably increased because of its wide use in solar cells, thermoelectric and electronic devices of the last generation. Despite such large use, scientific knowledge about volcanogenic tellurium is very poor. Few previous authors report result of tellurium concentrations in volcanic plume, among with other trace metals. They recognize this element as volatile, concluding that volcanic gases and sulfur deposits are usually enriched with tellurium. Here, we present some results on tellurium concentrations in volcanic emissions (plume, fumaroles, ash leachates) and in environmental matrices (soils and plants) affected by volcanic emissions and/or deposition. Samples were collected at Etna and Vulcano (Italy), Turrialba (Costa Rica), Miyakejima, Aso, Asama (Japan), Mutnovsky (Kamchatka) at the crater rims by using common filtration techniques for aerosols (polytetrafluoroethylene filters). Filters were both eluted with Millipore water and acid microwave digested, and analyzed by inductively coupled plasma mass spectrometry (ICP-MS). Volcanic ashes emitted during explosive events on Etna and Copahue (Argentina) were analyzed for tellurium bulk composition and after leaching experiments to evaluate the soluble fraction of tellurium. Soils and leaves of vegetation were also sampled close to active volcanic vents (Etna, Vulcano, Nisyros, Nyiragongo, Turrialba, Gorely and Masaya) and investigated for tellurium contents. Preliminary results showed very high enrichments of tellurium in volcanic emissions comparing with other volatile elements like mercury, arsenic, thallium and bismuth. This suggests a primary transport in the volatile phase, probably in gaseous form (as also suggested by recent studies) and/or as soluble salts (halides and/or sulfates) adsorbed on the surface of particulate particles and ashes. First

  9. Emplacement Scenarios for Volcanic Domes on Venus

    Science.gov (United States)

    Glaze, Lori S.; Baloga, Steve M.; Stofan, Ellen R.

    2012-01-01

    One key to understanding the history of resurfacing on Venus is better constraints on the emplacement timescales for the range of volcanic features visible on the surface. A figure shows a Magellan radar image and topography for a putative lava dome on Venus. 175 such domes have been identified with diameters ranging from 19 - 94 km, and estimated thicknesses as great as 4 km. These domes are thought to be volcanic in origin and to have formed by the flow of viscous fluid (i.e., lava) on the surface.

  10. Volcanic Pipe of the Namuaiv Mountain

    Directory of Open Access Journals (Sweden)

    Vladimir K. Karzhavin

    2011-12-01

    Full Text Available This research was aimed at reconstructing thermodynamic conditions required for the studied mineral assemblages to be created and exist in nature. The results of the investigations confirm to the recent ideas about an important, even leading, role of temperature, pressure and dioxide carbon in diamond formation in volcanic pipers. The results of this theoretical research allows assuming that one of the reasons for the absence of diamonds in the Namuaiv Mountain volcanic pipe may lie in the increased content of water and oxidizing environmental conditions of their formation

  11. The volcanic response to deglaciation: Evidence from glaciated arcs and a reassessment of global eruption records

    Science.gov (United States)

    Watt, Sebastian F. L.; Pyle, David M.; Mather, Tamsin A.

    Several lines of evidence have previously been used to suggest that ice retreat after the last glacial maximum (LGM) resulted in regionally-increased levels of volcanic activity. It has been proposed that this increase in volcanism was globally significant, forming a substantial component of the post-glacial rise in atmospheric CO2, and thereby contributing to climatic warming. However, as yet there has been no detailed investigation of activity in glaciated volcanic arcs following the LGM. Arc volcanism accounts for 90% of present-day subaerial volcanic eruptions. It is therefore important to constrain the impact of deglaciation on arc volcanoes, to understand fully the nature and magnitude of global-scale relationships between volcanism and glaciation. The first part of this paper examines the post-glacial explosive eruption history of the Andean southern volcanic zone (SVZ), a typical arc system, with additional data from the Kamchatka and Cascade arcs. In all cases, eruption rates in the early post-glacial period do not exceed those at later times at a statistically significant level. In part, the recognition and quantification of what may be small (i.e. less than a factor of two) increases in eruption rate is hindered by the size of our datasets. These datasets are limited to eruptions larger than 0.1 km3, because deviations from power-law magnitude-frequency relationships indicate strong relative under-sampling at smaller eruption volumes. In the southern SVZ, where ice unloading was greatest, eruption frequency in the early post-glacial period is approximately twice that of the mid post-glacial period (although frequency increases again in the late post-glacial). A comparable pattern occurs in Kamchatka, but is not observed in the Cascade arc. The early post-glacial period also coincides with a small number of very large explosive eruptions from the most active volcanoes in the southern and central SVZ, consistent with enhanced ponding of magma during

  12. Breast Self-Examination and breast cancer awareness in women in developing countries: a survey of women in Buea, Cameroon

    Directory of Open Access Journals (Sweden)

    Suh Mary Atanga

    2012-11-01

    Full Text Available Abstract Background Breast cancer is one of the leading causes of cancer morbidity and mortality worldwide. In Cameroon, breast cancer causes as many as 10.7 deaths per 100,000 women making it the second cause of cancer mortality. Better documenting women’s knowledge and practices on breast cancer and breast self-exam (BSE would be useful in the design of interventions aimed at preventing breast cancer. This study sought to 1. describe Cameroonian women’s knowledge of breast self-examination (BSE; 2. assess their impression on the practice of BSE and 3. describe their perceptions on the causes, risk factors and prevention of breast cancer. Methods A cross-sectional survey was conducted in a volunteer sample of 120 consenting women in Buea, Cameroon. Data were collected using a structured questionnaire self-administered by study participants. Results The sample was fairly educated with close to three quarters (70.83% having completed high school. Nearly three quarters (74.17% of participants had previously heard about BSE, however as many as 40% had never done a BSE. Although 95% of participants believed that breast cancer could be prevented, only 36.67% recognized breast examination as a prevention method. A substantial 13.33% thought that breast cancer could be prevented with a vaccine while 45% thought that dieting or exercising would prevent breast cancer. Similarly, 70% of participants thought that breast cancer could be treated, with 35.83% thinking that it could be treated medically while 34.17% thought it could be treated traditionally or spiritually. Conclusions The practice of BSE while perceived as being important is not frequent in these women in Buea, Cameroon. Health education campaigns are imperative to elucidate the public on the causes, risk factors and prevention of breast cancer. Further studies need to explore what interventions could be best used to improve the uptake and practice of BSE.

  13. Characterization of Bacillus anthracis-like bacteria isolated from wild great apes from Cote d'Ivoire and Cameroon.

    Science.gov (United States)

    Klee, Silke R; Ozel, Muhsin; Appel, Bernd; Boesch, Christophe; Ellerbrok, Heinz; Jacob, Daniela; Holland, Gudrun; Leendertz, Fabian H; Pauli, Georg; Grunow, Roland; Nattermann, Herbert

    2006-08-01

    We present the microbiological and molecular characterization of bacteria isolated from four chimpanzees and one gorilla thought to have died of an anthrax-like disease in Côte d'Ivoire and Cameroon. These isolates differed significantly from classic Bacillus anthracis by the following criteria: motility, resistance to the gamma phage, and, for isolates from Cameroon, resistance to penicillin G. A capsule was expressed not only after induction by CO(2) and bicarbonate but also under normal growth conditions. Subcultivation resulted in beta-hemolytic activity and gamma phage susceptibility in some subclones, suggesting differences in gene regulation compared to classic B. anthracis. The isolates from Côte d'Ivoire and Cameroon showed slight differences in their biochemical characteristics and MICs of different antibiotics but were identical in all molecular features and sequences analyzed. PCR and Southern blot analyses confirmed the presence of both the toxin and the capsule plasmid, with sizes corresponding to the B. anthracis virulence plasmids pXO1 and pXO2. Protective antigen was expressed and secreted into the culture supernatant. The isolates possessed variants of the Ba813 marker and the SG-749 fragment differing from that of classic B. anthracis strains. Multilocus sequence typing revealed a close relationship of our atypical isolates with both classic B. anthracis strains and two uncommonly virulent Bacillus cereus and Bacillus thuringiensis isolates. We propose that the newly discovered atypical B. anthracis strains share a common ancestor with classic B. anthracis or that they emerged recently by transfer of the B. anthracis plasmids to a strain of the B. cereus group.

  14. A new subtype (subgenotype) Ac (A3) of hepatitis B virus and recombination between genotypes A and E in Cameroon.

    Science.gov (United States)

    Kurbanov, Fuat; Tanaka, Yasuhito; Fujiwara, Kei; Sugauchi, Fuminaka; Mbanya, Dora; Zekeng, Leopold; Ndembi, Nicaise; Ngansop, Charlotte; Kaptue, Lazare; Miura, Tomoyuki; Ido, Eiji; Hayami, Masanori; Ichimura, Hiroshi; Mizokami, Masashi

    2005-07-01

    Blood samples (n=544) from two different populations (Pygmies and Bantus) in Cameroon, West Africa, were analysed. Serological tests indicated that the anti-hepatitis C virus (HCV) prevalence in Bantus (20.3 %) was higher than that in Pygmies (2.3 %, PHBV) serological markers was equally high in both populations: in total, 9.4, 17.3 and 86.8 % for HBsAg, anti-HBs and anti-HBc, respectively. HBV genotype A (HBV/A) and HBV/E were predominant (43.5 % each) in both populations, and HBV/D was found in a minority (13 %). The preS/S region was sequenced in nine cases (five HBV/A and four HBV/E) and the complete genome in six cases (four HBV/A and two HBV/E). Subsequent phylogenetic analysis revealed that the HBV/A strains were distinct from the subtypes (subgenotypes) described previously, Ae (A2) and Aa (A1), and in the preS/S region they clustered with previously reported sequences from Cameroon. Based on the nucleotide difference from Aa (A1) and Ae (A2), more than 4 % in the complete genome, the Cameroonian strains were suggested to represent a new subtype (subgenotype), designated HBV/Ac (A3). A high (3.9 %) nucleotide divergence in HBV/Ac (A3) strains suggested that the subtype (subgenotype) has a long natural history in the population of Cameroon. One of the HBV/Ac (A3) strains was found to be a recombinant with an HBV/E-specific sequence in the polymerase reverse transcriptase domain. Further cohort studies will be required to assess detailed epidemiological, virological and clinical characteristics of HBV/Ac (A3), as well as its recombinant form.

  15. An ethical approach to socio-economic information sources in ongoing vulnerability and resilience studies: the Mount Cameroon case

    Directory of Open Access Journals (Sweden)

    Maria Ilaria Pannaccione Apa

    2012-07-01

    Full Text Available The study of the vulnerability of facing natural and man-made hazards, with the related resilient answers belong to the complex and articulate field of social sciences called ‘Disaster Anthropology’. Vulnerability is generally defined as a weak point in facing an aggressive event that is difficult to manage. Resilience is the subsequent capacity for self-repair after a sustained natural or anthropogenic stress. Consequently, the theoretical model of economic resilience is the ability to restore an economic background that can support the gradual recovery of social benefits following a disaster. Moreover, the presence in the territory of different systems of production (natural eco-systems and/or technical systems should allow multi-resilient communities. The mathematical structure of these economic theorems makes their practical application difficult inside an ethno-anthropological context, as it conflicts with cultural variables of the socio-structural fabric. An example can be given by some urban and rural family structures that are settled around the Mount Cameroon volcano (southwest Cameroon, in which the general psychological pressure increases because of both the constant exposure to natural hazards and the vulnerability arising from its social environment (e.g. castes, forced housing allocation, cultural estrangement to local chiefdom. Therefore, the rational heuristic model to be adopted in this social vulnerability study is performed by several combined analyses that have many interpretive obstacles. In 2009, within FP7-MIA-VITA, the first fieldwork mission for the study of socio-economic development of communities living around Mount Cameroon was launched. This completed 108 interviews across several social groups of different ethnicities and religions. The resulting information is being re-tested and verified from the second fieldwork mission in 2011, for completion of the study area.

  16. Plate Tectonic Setting and Eruptive Characteristics of the K—rich Volcanic Belt in HeilingJiang Province,Northeast China

    Institute of Scientific and Technical Information of China (English)

    邱家骧; 吴志勤; 等

    1990-01-01

    Various lines of geological,geophysical and geochemical evidence indicate that the K-rich volcanic belt in Northeast China as represented by the volcanic groups at Wudalianchi,Erkeshan and Kelo was developed,in terms of plate tectonics,in a rift valley system within the continental plate,The volcanic material includes effusive lavas and explosive pyroclastics whose characteristics and flowing/accumulation mechanisms were studied in detail,The distribution of pyroclastics shows that the eruption is of Strombolian type with increasing intensity towards the late stages.

  17. Malaria and colonialism in the German colonies New Guinea and the Cameroons. Research, control, thoughts of eradication.

    Science.gov (United States)

    Eckart, W U

    1998-06-01

    German malaria research during the colonial period took place between medical and political interests. In the field of zoological and clinical research of malaria Germany was not a pioneer. Nevertheless, Robert Koch forced by impressive Italian results tried to participate in malaria research on the field of acquired malaria immunity and by optimizing the therapeutic doses of quinine in German New Guinea. In the German Cameroons, on the other hand, the fight against malaria was completely dominated by racial and political arguments. The paper tries to shed light on this dichotomy, which turned out to be not very productive.

  18. The impact of signing a memorandum of understanding on reproductive health with the Ministry of Public Health in Cameroon.

    Science.gov (United States)

    Leke, Robert J I; Njotang, Nana P; Shearon, Azong B; Wankah, Charlotte A

    2014-10-01

    Health statistics relating to Millennium Development Goals 4 and 5 are poor for most low-resource countries. Professional societies can assist governments to improve these health indicators. For an effective collaboration, the Society of Gynaecologists and Obstetricians Cameroon (SOGOC) and the Ministry of Public Health signed a memorandum of understanding on reproductive health. A major consequence of this collaboration was the ease of transfer of competence associated with SOGOC adopting a monitoring and evaluation role, which has improved quality of care. The impact of this collaboration for the Society has been significant; SOGOC is recognized as a partner and has an opportunity to play a leadership role in issues concerning reproductive health.

  19. A FIELD STUDY OF INDICATORS OF THE PERFORMANCE OF FOUR ABSORPTION CHILLERS IN THE SUDANO-SAHELIAN REGION OF CAMEROON

    OpenAIRE

    A. N. N. Chedop; N. Djongyang; R.Tchinda; Zaatri, A.; J. D. Kana

    2016-01-01

    This paper presents a field study of indicators of the performance of absorption refrigerating systems in the Sudano-Sahelian region of Cameroon. A modeling of various components of the system is performed in order to choose the technology best adapted for the region. Based on the characteristics from the manufacturers, four absorption chillers were studied; namely: EAW Schüco LB 15 and 30; Rotartica Solar 045 and Sonnenklima Suninverse. The model of Kühn and Ziegler and meteorological data o...

  20. Composition, structure, origin, and evolution of off-axis linear volcanic structures of the Brazil Basin, South Atlantic

    Science.gov (United States)

    Skolotnev, S. G.; Peive, A. A.

    2017-01-01

    The paper considers the conditions and mechanisms of the formation of linear volcanic structures in the Brazil Basin, South Atlantic. Among these objects, those related to the ascent of deep mantle plumes predominate. It is shown that the ascent of melts from plume sources leads to the formation of (a) hot spot tracks in the form of linear volcanic ridges and (b) active hot lines in the form of submarine mountain chains with trends differing from those of hot spot tracks and with a more variable character of the age distribution of volcanic rocks. Fault tectonics affects the character of plume activity. In addition, plume material from a hot spot area is dragged by a moving plate as a flow or a sublithospheric lens, which leads to the long-term existence of particular independent segments of linear structures and sometimes to late volcanism reactivation within their limits. Decompression melting of the asthenospheric mantle in zones where thin lithosphere undergoes tension causes the formation of passive hot lines. The main mantle source for the considered volcanic rocks was a mixture of DMM and HIMU mantle components, with the latter abruptly dominating. In marginal oceanic regions, the EM1 component is also present (the EM2 component is found more rarely) within fragments of tectonically delaminated continental mantle that was trapped by the oceanic mantle during the breakup of Gondwana.

  1. Organic Entrainment and Preservation in Volcanic Glasses

    Science.gov (United States)

    Wilhelm, Mary Beth; Ojha, Lujendra; Brunner, Anna E.; Dufek, Josef D.; Wray, James Joseph

    2014-01-01

    Unaltered pyroclastic deposits have previously been deemed to have "low" potential for the formation, concentration and preservation of organic material on the Martian surface. Yet volcanic glasses that have solidified very quickly after an eruption may be good candidates for containment and preservation of refractory organic material that existed in a biologic system pre-eruption due to their impermeability and ability to attenuate UV radiation. Analysis using NanoSIMS of volcanic glass could then be performed to both deduce carbon isotope ratios that indicate biologic origin and confirm entrainment during eruption. Terrestrial contamination is one of the biggest barriers to definitive Martian organic identification in soil and rock samples. While there is a greater potential to concentrate organics in sedimentary strata, volcanic glasses may better encapsulate and preserve organics over long time scales, and are widespread on Mars. If volcanic glass from many sites on Earth could be shown to contain biologically derived organics from the original environment, there could be significant implications for the search for biomarkers in ancient Martian environments.

  2. Monogenetic volcanism: personal views and discussion

    Science.gov (United States)

    Németh, K.; Kereszturi, G.

    2015-11-01

    Monogenetic volcanism produces small-volume volcanoes with a wide range of eruptive styles, lithological features and geomorphic architectures. They are classified as spatter cones, scoria (or cinder) cones, tuff rings, maars (maar-diatremes) and tuff cones based on the magma/water ratio, dominant eruption styles and their typical surface morphotypes. The common interplay between internal, such as the physical-chemical characteristics of magma, and external parameters, such as groundwater flow, substrate characteristics or topography, plays an important role in creating small-volume volcanoes with diverse architectures, which can give the impression of complexity and of similarities to large-volume polygenetic volcanoes. In spite of this volcanic facies complexity, we defend the term "monogenetic volcano" and highlight the term's value, especially to express volcano morphotypes. This study defines a monogenetic volcano, a volcanic edifice with a small cumulative volume (typically ≤1 km3) that has been built up by one continuous, or many discontinuous, small eruptions fed from one or multiple magma batches. This definition provides a reasonable explanation of the recently recognized chemical diversities of this type of volcanism.

  3. Monitoring and forecasting Etna volcanic plumes

    Directory of Open Access Journals (Sweden)

    S. Scollo

    2009-09-01

    Full Text Available In this paper we describe the results of a project ongoing at the Istituto Nazionale di Geofisica e Vulcanologia (INGV. The objective is to develop and implement a system for monitoring and forecasting volcanic plumes of Etna. Monitoring is based at present by multispectral infrared measurements from the Spin Enhanced Visible and Infrared Imager on board the Meteosat Second Generation geosynchronous satellite, visual and thermal cameras, and three radar disdrometers able to detect ash dispersal and fallout. Forecasting is performed by using automatic procedures for: i downloading weather forecast data from meteorological mesoscale models; ii running models of tephra dispersal, iii plotting hazard maps of volcanic ash dispersal and deposition for certain scenarios and, iv publishing the results on a web-site dedicated to the Italian Civil Protection. Simulations are based on eruptive scenarios obtained by analysing field data collected after the end of recent Etna eruptions. Forecasting is, hence, supported by plume observations carried out by the monitoring system. The system was tested on some explosive events occurred during 2006 and 2007 successfully. The potentiality use of monitoring and forecasting Etna volcanic plumes, in a way to prevent threats to aviation from volcanic ash, is finally discussed.

  4. Impact of Volcanic Activity on AMC Channel Operations

    Science.gov (United States)

    2014-06-13

    IMPACT OF VOLCANIC ACTIVITY ON AMC CHANNEL OPERATIONS GRADUATE RESEARCH PROJECT Matthew D... VOLCANIC ACTIVITY ON AMC CHANNEL OPERATIONS GRADUATE RESEARCH PROJECT Presented to the Faculty Department of Operational Sciences...AFIT-ENS-GRP-14-J-11 IMPACT OF VOLCANIC ACTIVITY ON AMC CHANNEL OPERATIONS Matthew D. Meshanko, BS, MA Major, USAF

  5. Implications of volcanic erratics in Quaternary deposits of North Greenland

    DEFF Research Database (Denmark)

    Funder, Svend Visby; Larsen, Ole

    1982-01-01

    Erratic boulders, petrographically similar to the volcanics exposed around Kap Washington, are found on islands and along the coast much further to the east. Isotopic measurements on two such boulders show that these volcanic rocks are of the same age as the Kap Washington volcanics. The regional...

  6. Yellow fever control in Cameroon: Where are we now and where are we going?

    Directory of Open Access Journals (Sweden)

    Mimbouga Julienne

    2008-02-01

    Full Text Available Abstract Background Cameroon is one of 12 African countries that bear most of the global burden of yellow fever. In 2002 the country developed a five-year strategic plan for yellow fever control, which included strategies for prevention as well as rapid detection and response to outbreaks when they occur. We have used data collected by the national Expanded Programme on Immunisation to assess the progress made and challenges faced during the first four years of implementing the plan. Methods In January 2003, case-based surveillance of suspected yellow fever cases was instituted in the whole country. A year later, yellow fever immunisation at nine months of age (the same age as routine measles immunisation was introduced. Supplementary immunisation activities (SIAs, both preventive and in response to outbreaks, also formed an integral part of the yellow fever control plan. Each level of the national health system makes a synthesis of its activities and sends this to the next higher level at defined regular intervals; monthly for routine data and daily for SIAs. Results From 2004 to 2006 the national routine yellow fever vaccination coverage rose from 58.7% to 72.2%. In addition, the country achieved parity between yellow fever and measles vaccination coverage in 2005 and has since maintained this performance level. The number of suspected yellow fever cases in the country increased from 156 in 2003 to 859 in 2006, and the proportion of districts that reported at least one suspected yellow fever case per year increased from 31.4% to 68.2%, respectively. Blood specimens were collected from all suspected cases (within 14 days of onset of symptoms and tested at a central laboratory for yellow fever IgM antibodies; leading to confirmation of yellow fever outbreaks in the health districts of Bafia, Méri and Ntui in 2003, Ngaoundéré Rural in 2004, Yoko in 2005 and Messamena in 2006. Owing to constraints in rapidly mobilising the necessary resources

  7. Holocene explosive volcanism of the Jan Mayen (island) volcanic province, North-Atlantic

    Science.gov (United States)

    Gjerløw, Eirik; Haflidason, H.; Pedersen, R. B.

    2016-07-01

    The volcanic island Jan Mayen, located in the Norwegian-Greenland Sea, hosts the active stratovolcano of Beerenberg, the northernmost active subaerial volcano in the world. At least five eruptions are known from the island following its discovery in the 17th century, but its eruptive history prior to this is basically unknown. In this paper two sediment cores retrieved close to Jan Mayen have been studied in detail to shed light on the Holocene history of explosive volcanism from the Jan Mayen volcanic province. Horizons with elevated tephra concentrations were identified and tephra from these was analysed to determine major element chemistry of the tephra. The tephra chemistry was used to provide a link between the two cores and the land based tephra records from Jan Mayen Island. We managed to link two well-developed tephra peaks in the cores by their geochemical composition and age to Jan Mayen. One of these peaks represents the 1732 AD eruption of Eggøya while the other peak represents a previously undescribed eruption dated to around 10.3 ka BP. Two less prominent tephra peaks, one in each core, dated to approximately 2.3 and 3.0 ka BP, also have a distinct geochemical character linking them to Jan Mayen volcanism. However, the most prominent tephra layer in the cores located close to Jan Mayen and numerous other cores along the Jan Mayen ridge is the 12.1 ka BP Vedde Ash originating from the Iceland volcanic province. We find that the Holocene volcanism on Jan Mayen is much less explosive than volcanism in Iceland, and propose that either low amounts of explosive volcanic activity from the summit region of Beerenberg or small to absent glacier cover on Beerenberg is responsible for this.

  8. Calibration of microbolometer infrared cameras for measuring volcanic ash mass loading

    Science.gov (United States)

    Carroll, Russell C.

    Small spacecraft with thermal infrared (TIR) imaging capabilities are needed to detect dangerous levels of volcanic ash that can severely damage jet aircraft engines and must be avoided. Grounding aircraft after a volcanic eruption may cost the airlines millions of dollars per day, while accurate knowledge of volcanic ash density might allow for safely routing aircraft around dangerous levels of volcanic ash. There are currently limited numbers of satellites with TIR imaging capabilities so the elapsed time between revisits can be large, and these instruments can only resolve total mass loading along the line-of-sight. Multiple small satellites could allow for decreased revisit times as well as multiple viewing angles to reveal the three-dimensional structure of the ash cloud through stereoscopic techniques. This paper presents the design and laboratory evaluation of a TIR imaging system that is designed to fit within the resource constraints of a multi-unit CubeSat to detect volcanic ash mass loading. The laboratory prototype of this TIR imaging system uses a commercial off-the shelf (COTS) camera with an uncooled microbolometer sensor, two narrowband filters, a black body source and a custom filter wheel. The infrared imaging system detects the difference in attenuation of volcanic ash at 11 mum and 12 mum by measuring the brightness temperature at each band. The brightness temperature difference method is used to measure the column mass loading. Multi-aspect images and stereoscopic techniques are needed to estimate the mass density from the mass loading, which is the measured mass per unit area. Laboratory measurements are used to characterize the noise level and thermal stability of the sensor. A calibration technique is developed to compensate for sensor temperature drift. The detection threshold of volcanic ash density of this TIR imaging system is found to be from 0.35 mg/m3 to 26 mg/m3 for ash clouds that have thickness of 1 km, while ash cloud densities

  9. Geochemical signatures of the diffuse CO2 emission from Brava volcanic system, Cape Verde

    Science.gov (United States)

    Rodriguez, F.; Bandomo, Z.; Barros, I.; Dias Fonseca, J.; Fernandes, P.; Rodrigues, J.; Melian Rodriguez, G.; Padron, E.; Dionis, S.; Sonia, S.; Gonçalves, A.; Fernandes, A.; Hernandez Perez, P. A.; Perez, N.

    2010-12-01

    Brava (67 km2) the smallest of the populated Cape Verde islands, lies at the southwestern end of the archipelagic crescent. Brava volcanic system has no documented historical eruptions, but its youthful volcanic morphology and the fact that earthquake swarms still occur indicate the potential for future eruptions. A geochemical survey of diffuse gas emissions was carried out in Brava island during February and March 2010. For this survey 228 sampling sites were selected all over the island to perform soil CO2 efflux measurements, using a portable accumulation chamber and an IR sensor, and soil temperature measurements at a depth of 30-50 cm. Soil gas samples were collected at 40 cm depth for chemical (He, H2, N2, CO2, CH4, Ar and O2) and isotopic (δ13C-CO2) analysis in 32 selected sampling sites. CO2 efflux values ranged from non-detectable up to 1.343 g m-2 d-1. To quantify the total diffuse CO2 emission from Brava volcanic system, a CO2 efflux map was constructed using sequential Gaussian simulations (sGs). Most of the studied area showed background levels of CO2 efflux (˜2 g m-2 d-1), while peak levels (>1300 g m-2 d-1) were mainly identified at Vinagre and Baleia areas. The total diffuse CO2 output from Brava volcanic system was estimated about 41.6 t d-1. The analysis of the carbon isotopic signature of the CO2 in the soil atmosphere provides an insight for evaluating the origin of the diffuse CO2 emission. Observed δ13C-CO2 values ranged from -20.86 to -1.26 ‰. A binary plot of CO2 concentrations versus δ13C-CO2 values allows us to represent three major geochemical reservoirs (atmospheric air, volcanic gas, and biogenic gas) and their related mixing lines. The chemical and isotopic analysis of Brava soil gas samples suggest a mixing with deep-seated CO2 and biogenic gas for the diffuse CO2 emission from Brava volcanic system. The lack of visible volcanic gas emission in Brava highlights the importance of monitoring diffuse CO2 emission to improve its

  10. Perceived social approval and condom use with casual partners among youth in urban Cameroon

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    Meekers Dominique

    2011-08-01

    Full Text Available Abstract Background HIV prevention programs targeting youth often emphasize the role of peers, and assume that youths will model their behavior after their peers'. We challenge this view; we argue that adopting a given behavior requires social approval, and that youths do not necessarily turn to peers for such approval. This study analyzes survey data on youths in urban Cameroon to 1 identify which type of persons youths look to for social approval, and 2 establish how important social approval by these persons is for condom use among youths. Methods We analyzed data from three survey waves (2000, 2002, and 2003 of a reproductive health survey conducted among urban Cameroonian youth (aged 15-24. Only respondents who reported having at least one casual partner in the past year were retained for the analysis. Bivariate analyses and structural equation modeling were used to examine relationships among perceived social approval, attitudes towards condoms and condom use. Results The data show that only 3% of youths named their friends as people whose opinion they valued, while 93% mentioned family members. The perceived approval of condom use by these persons had a significant positive effect on the frequency of condom use among youths. The frequency of condom use was also affected by the respondents' attitudes toward condom use, the range of persons with whom they discussed reproductive health matters, whether they were enrolled in school, socioeconomic status, their self-efficacy, perceived severity of AIDS, risk perception and sexual risk behavior. The perceived social approval of condom use and the respondents' own condom attitudes were correlated. Conclusions Our analysis demonstrates that perceived social approval facilitates the adoption of condom use among urban Cameroonian youth. However, youths tend to value the opinions of family members much more than the opinions of their peers. These results suggest that interventions targeting youths

  11. Impact of land management system on crop yields and soil fertility in Cameroon

    Science.gov (United States)

    Tsozué, D.; Nghonda, J. P.; Mekem, D. L.

    2015-09-01

    The impact of direct-seeding mulch-based cropping systems (DMC), direct seeding (DS) and tillage seeding (TS) on Sorghum yields, soil fertility and the rehabilitation of degraded soils was evaluated in northern Cameroon. Field work consisted of visual examination, soil sampling, yield and rainfall data collection. Three fertilization rates (F1: 100 kg ha-1 NPK + 25 kg ha-1 of urea in DMC, F2: 200 kg ha-1 NPK + 50 kg ha-1 of urea in DMC and F3: 300 kg ha-1 NPK + 100 kg ha-1 of urea in DMC) were applied to each cropping system (DS, TS and DMC), resulting in nine experimental plots. Two types of chemical fertilizer were used (NPK 22.10.15 and urea) and applied each year from 2002 to 2012. Average Sorghum yields were 1239, 863 and 960 kg ha-1 in DMC, DS and TS, respectively, at F1, 1658, 1139 and 1192 kg ha-1 in DMC, DS and TS, respectively, at F2, and 2270, 2138 and 1780 kg ha-1 in DMC, DS and TS, respectively, at F3. pH values were 5.2-5.7 under DMC, 4.9-5.3 under DS and TS and 5.6 in the control sample. High values of cation exchange capacity were recorded in the control sample, TS system and F1 of DMC. Base saturation rates, total nitrogen and organic matter contents were higher in the control sample and DMC than in the other systems. All studied soils were permanently not suitable for Sorghum due to the high percentage of nodules. F1 and F2 of the DS were currently not suitable, while F1 and F3 of DMC, F3 of DS and F1, F2 and F3 of TS were marginally suitable for Sorghum due to low pH values.

  12. Influence of Processing Methods on Proximate Composition and Dieting of Two Amaranthus Species from West Cameroon

    Science.gov (United States)

    Suffo Kamela, Arnaud Landry; Mouokeu, Raymond Simplice; Ashish, Rawson; Maffo Tazoho, Ghislain; Glory Moh, Lamye; Pamo Tedonkeng, Etienne

    2016-01-01

    The effects of various processing methods on the proximate composition and dieting of Amaranthus hybridus and Amaranthus cruentus from West Cameroon were investigated in this study. Both amaranths leaves were subjected to same treatments (sun-dried and unsliced, sliced and cooked), milled, and analysed for their mineral and proximate composition. Thirty-Six Wistar albino rats of 21 to 24 days old were distributed in six groups and fed for 14 days with 10% protein based diets named D0 (protein-free diet), DI (egg white as reference protein), DII (sun-dried and unsliced A. hybridus), DIII (cooked and sliced A. hybridus), DIV (sun-dried and unsliced A. cruentus), and DV (cooked and sliced A. cruentus). The protein bioavailability and haematological and biochemical parameters were assessed in rats. The results showed that K, P, Mg, Zn, and Fe had the higher content in both samples regardless of processing method. The sun-dried and unsliced A. cruentus contained the highest value of crude protein 32.22 g/100 g DM (dry matter) while the highest crude lipid, 3.80 and 2.58%, was observed, respectively, in sun-dried and unsliced A. hybridus and cooked and sliced A. cruentus. Cooked and sliced A. hybridus and A. cruentus contained high crude fiber of 14 and 12.18%, respectively. Rats fed with diet DIII revealed the best protein bioavailability and haematological parameters whereas 100% mortality rate was recorded with group fed with diet DIV. From this study, it is evident that cooked and sliced A. hybridus and A. cruentus could play a role in weight reduction regimes. PMID:28078277

  13. Heavy metals in five leafy vegetables from urban and periurban sites in Ngaoundere, Cameroon

    Directory of Open Access Journals (Sweden)

    R. Adjia1

    2010-01-01

    Full Text Available Heavy metal concentrations were estimated in five leafy vegetables (Solanum nigrum, Brassica oleraceae, Lactuca sativa, Amaranthus hybridus and Corchorus olitorius from urban and periurban sites in Ngaoundere (Cameroon using an Atomic Absorption Spectrophotometer (AAS. Vegetable samples were collected at the two stages of maturity: stage I (60 days and stage II (90 days for analysis. The results showed that the concentrations of heavy metals in all vegetables were greater in urban site than in periurban site. The highest concentrations of Fe (673.92 mg/kg DW, Cu (10.42 mg/kg, Cd (1.70 mg/kg DW, and Pb (31.75 mg/kg DW were recorded in Lactuca sativa, Zn (94.60 mg/kg DW in Solanum nigrum, and Ni (16.91 mg/kg DW in Corchorus olitorius. The concentrations of Cu, and Pb were greater in roots than in aerial parts, while Fe, Cd, Ni and Zn concentrations were greater in aerial parts than in roots. Some of the concentrations of Ni, Zn and Pb in crops reached the critical level for plant growth. In general, the results indicated that the consumption of leafy vegetables harvested at the stage II potentially provides the greatest amount of heavy metals. The transportation index (Ti decreased in vegetables harvested at the stage II for Fe, Cu, Cd and Zn but slightly increased for Ni and Pb, suggesting that heavy metal transportation from roots to aerial parts depends on the plant phenology and metal species. In all farms and at the two stages of maturity, the lead concentrations in all vegetables were more than the FAO/WHO maximum recommended level in leafy vegetable for human consumption. Moreover, all vegetables had some Cd concentrations that were higher than limits set by FAO/WHO. So, they are not suitable for human consumption.

  14. Can mima-like mounds be Vertisol relics (Far North Region of Cameroon, Chad Basin)?

    Science.gov (United States)

    Diaz, Nathalie; Dietrich, Fabienne; Cailleau, Guillaume; Sebag, David; Ngounou Ngatcha, Benjamin; Verrecchia, Eric P.

    2016-05-01

    Non-anthropogenic earth mounds, defined as mima-like mounds in this study, have recently been observed in non-carbonate watersheds along the Sudano-Sahelian belt in the Chad Basin. In the Diamare piedmont (northern Cameroon) they are particularly well developed within stream networks. In less eroded areas, they occur as whaleback, flattened morphologies, or even as buried features. All these shapes are composed of clay-rich sediment associated with high proportions of secondary carbonate nodules and Fesbnd Mn micro-nodules. Their soil structure is prismatic to massive and vertical cracks are observed locally. Grain-size distributions emphasize the clay-rich nature of the sediment, with average clay contents of 32% ± 12.8% (n = 186), which is significantly higher than the clay content in the adjacent sediments in the landscape (mean = 10% ± 4%, n = 21). Moreover, high proportions of smectite characterize the soil, with average contents of 34 ± 7% (n = 25). At the micro-scale, the groundmass has a cross-striated b-fabric, with embedded smooth subangular quartz and feldspar grains of the silt-size fraction. All the characteristics point to altered vertic properties in the clay-rich sediment composing the mima-like mounds. Mima-like mounds are thus interpreted as degraded Vertisols. Compared to present-day Vertisols occurring in the piedmont, mima-like mounds are located upstream. It is thus proposed that the Vertisol areas were more extensive during a former and wetter period than the present-day. Subsequent changing climatic conditions increased erosion, revealing the gilgai micro-relief by preferential erosion in micro-lows rather than in micro-highs. Mima-like mounds of the Chad Basin might thus result from pedogenesis combined with later erosion. These local processes can be inherited from regional climatic variations during the Late Pleistocene-Holocene and likely be related to the African Humid Period.

  15. Domestic animals as potential reservoir hosts of Trypanosoma brucei gambiense in sleeping sickness foci in Cameroon

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    Njiokou F.

    2010-03-01

    Full Text Available An explanation of the endemic nature and/or the resurgence of Human African Trypanosomiasis (HAT in the historic foci in West and Central Africa may be the existence of an animal reservoir. In some HAT foci, pigs were found infected by Trypanosoma brucei gambiense but the implication of the other domestic animals was not quite evaluated. This study aims to determine the prevalence of T. b. gambiense in domestic animal species (goat, sheep, pig and dog commonly found in the four active HAT foci in Cameroon (Bipindi, Fontem, Campo and Doumé. Blood samples were collected from 307 pigs, 264 goats, 267 sheep and 37 dogs and used for parasitological (QBC, immunological (LiTat 1.3 CATT and molecular (PCR analyses. QBC detected trypanosomes in 3.88 % domestic animals while 22.7 % were sero-positive with LiTat 1.3 CATT tests. Of the 875 animals analysed, 174 (19.88 % harboured T. brucei s.l. DNA, found in each of the four types of animal and in the four localities. The infection rate significantly differed among the animal species (p < 0.0001 and localities (p < 0.0001. The PCR also revealed T. b. gambiense group 1 DNA in 27 (3.08 % domestic animals. The specific infection rates were as follows: sheep (6.74 %, goats (3.08 %, pigs (0.32 % and dogs (0 %. T. b. gambiense was found in 8 (3.92 % animals from Bipindi, 15 (4.83 % from Campo, 4 (2.59 % from Fontem-Center and none from Doumé. The infection rates significantly differed between the localities, and correlated with the intensity of HAT transmission in the foci.

  16. [Guidelines for evaluating the viability of health care centers: test in northern Cameroon].

    Science.gov (United States)

    Bene, T; Mevel, A; Yougouda, A; Fontaine, D

    1998-01-01

    A working group has developed a manual of practical guidelines for evaluating the viability of health care centers (HCC). These guidelines were tested in 1996 at the HCC in Badjouma, Cameroon. Viability is assessed in three dimensions, i.e. quality of care, cost-effectiveness, and institutional efficacy on the basis of the demand for services, staff requirements, cash flow, and supply costs. Regular evaluation of these parameters allows identification of areas requiring improvement to enhance the viability of the HCC. With only 0.29 visits per year per inhabitant, the attendance rate at the Badjouma facility is low. Public appeal is adversely affected by an under-qualified staff and poor equipment. Overall operating expenses are 6.8 million CFA francs per year and depreciation costs are 1.7 million CFA francs per year. Direct proceeds related to health care services (mainly sale of medication) are 4.1 million CFA francs. The remaining sources of revenue are state subsidies (2.5 million CFA francs) and international aid (0.4 million CFA francs). The deficit is 1.5 million CFA francs corresponding mainly to depreciation costs. Evaluation of the financial viability based on service-generated revenues alone (49%) and on combined domestic revenues, i.e. service revenues and state subsidies (79%), shows that the HCC depends mainly on depreciation costs. Analysis of institutional efficacy by comparing real activity with activity defined in official texts showed that the state was the main decision-maker but also revealed a tendency to pass off responsibility due to poorly defined command structure. The results of this test validate the proposed manual as a tool for global analysis of the activity and relevance of a HCC. Findings can be used to draw conclusions on the effects of national health policies at the local level.

  17. Generalized Extreme Value Distribution Models for the Assessment of Seasonal Wind Energy Potential of Debuncha, Cameroon

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    Nkongho Ayuketang Arreyndip

    2016-01-01

    Full Text Available The method of generalized extreme value family of distributions (Weibull, Gumbel, and Frechet is employed for the first time to assess the wind energy potential of Debuncha, South-West Cameroon, and to study the variation of energy over the seasons on this site. The 29-year (1983–2013 average daily wind speed data over Debuncha due to missing values in the years 1992 and 1994 is gotten from NASA satellite data through the RETScreen software tool provided by CANMET Canada. The data is partitioned into min-monthly, mean-monthly, and max-monthly data and fitted using maximum likelihood method to the two-parameter Weibull, Gumbel, and Frechet distributions for the purpose of determining the best fit to be used for assessing the wind energy potential on this site. The respective shape and scale parameters are estimated. By making use of the P values of the Kolmogorov-Smirnov statistic (K-S and the standard error (s.e analysis, the results show that the Frechet distribution best fits the min-monthly, mean-monthly, and max-monthly data compared to the Weibull and Gumbel distributions. Wind speed distributions and wind power densities of both the wet and dry seasons are compared. The results show that the wind power density of the wet season was higher than in the dry season. The wind speeds at this site seem quite low; maximum wind speeds are listed as between 3.1 and 4.2 m/s, which is below the cut-in wind speed of many modern turbines (6–10 m/s. However, we recommend the installation of low cut-in wind turbines like the Savonius or Aircon (10 KW for stand-alone low energy need.

  18. Characterizing the phylogenetic tree community structure of a protected tropical rain forest area in Cameroon.

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    Stéphanie Manel

    Full Text Available Tropical rain forests, the richest terrestrial ecosystems in biodiversity on Earth are highly threatened by global changes. This paper aims to infer the mechanisms governing species tree assemblages by characterizing the phylogenetic structure of a tropical rain forest in a protected area of the Congo Basin, the Dja Faunal Reserve (Cameroon. We re-analyzed a dataset of 11538 individuals belonging to 372 taxa found along nine transects spanning five habitat types. We generated a dated phylogenetic tree including all sampled taxa to partition the phylogenetic diversity of the nine transects into alpha and beta components at the level of the transects and of the habitat types. The variation in phylogenetic composition among transects did not deviate from a random pattern at the scale of the Dja Faunal Reserve, probably due to a common history and weak environmental variation across the park. This lack of phylogenetic structure combined with an isolation-by-distance pattern of taxonomic diversity suggests that neutral dispersal limitation is a major driver of community assembly in the Dja. To assess any lack of sensitivity to the variation in habitat types, we restricted the analyses of transects to the terra firme primary forest and found results consistent with those of the whole dataset at the level of the transects. Additionally to previous analyses, we detected a weak but significant phylogenetic turnover among habitat types, suggesting that species sort in varying environments, even though it is not predominating on the overall phylogenetic structure. Finer analyses of clades indicated a signal of clustering for species from the Annonaceae family, while species from the Apocynaceae family indicated overdispersion. These results can contribute to the conservation of the park by improving our understanding of the processes dictating community assembly in these hyperdiverse but threatened regions of the world.

  19. Serological studies of neurologic helminthic infections in rural areas of southwest cameroon: toxocariasis, cysticercosis and paragonimiasis.

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    Agathe Nkouawa

    Full Text Available BACKGROUND: Both epilepsy and paragonimiasis had been known to be endemic in Southwest Cameroon. A total of 188 people (168 and 20 with and without symptoms confirmed by clinicians, respectively, 84.6% under 20 years old were selected on a voluntary basis. Among 14 people (8.3% with history of epilepsy, only one suffered from paragonimiasis. Therefore, we challenged to check antibody responses to highly specific diagnostic recombinant antigens for two other helminthic diseases, cysticercosis and toxocariasis, expected to be involved in neurological diseases. Soil-transmitted helminthic infections were also examined. METHODOLOGY/PRINCIPAL FINDINGS: Fecal samples were collected exclusively from the 168 people. Eggs of Ascaris lumbricoides, Trichuris trichiura and hookworms were found from 56 (33.3%, 72 (42.8%, and 19 (11.3% persons, respectively. Serology revealed that 61 (36.3%, 25 (14.9% and 2 (1.2% of 168 persons showed specific antibody responses to toxocariasis, paragonimiasis and cysticercosis, respectively. By contrast, 20 people without any symptoms as well as additional 20 people from Japan showed no antibody responses. Among the 14 persons with epilepsy, 5 persons were seropositive to the antigen specific to Toxocara, and one of them was simultaneously positive to the antigens of Paragonimus. The fact that 2 children with no history of epilepsy were serologically confirmed to have cysticercosis strongly suggests that serological survey for cysticercosis in children is expected to be useful for early detection of asymptomatic cysticercosis in endemic areas. CONCLUSIONS/SIGNIFICANCE: Among persons surveyed, toxocariasis was more common than paragonimiasis, but cysticercosis was very rare. However, the fact that 2 children were serologically confirmed to have cysticercosis was very important, since it strongly suggests that serology for cysticercosis is useful and feasible for detection of asymptomatic cysticercotic children in endemic

  20. Haemostatic trends in HIV-infected individuals in Yaoundé, Cameroon: a pilot study

    Science.gov (United States)

    Tene, Larissa; Tagny, Claude T.; Mintya-Ndoumba, Annick; Fossi, Vincent N.; Mbanya, Dora

    2016-01-01

    Bleeding disorders are haematological manifestations that are frequently observed during HIV infection. This study intends to describe the haemostatic trends in HIV-infected patients in Cameroon. This cross-sectional descriptive study was carried out at the haematology unit of the Yaoundé University Teaching Hospital from March to June 2012. It included consenting HIV-positive patients, aged 18 years and above, naive to antiretroviral treatment or not. The coagulation profile was measured with Stago reagents (Stago Diagnostics, Asnières sur Seine, France) using a chronometric technique on a semi-automate (Stago Diagnostics). Platelets count was estimated on a human count automate (Human diagnostic, Wiesbaden, Germany) by flow cytometry. A total of 139 HIV-infected patients were included in this study, out of which 106 were females (76.3%) against 33 (23.7%) males, giving a sex ratio of 0.3 (M/F). Mean age was 38.85 years (range 22–73 years) and median CD4 count was 353 cells/μl (Interquartile range 200–500 cells/μl). Hyperfibrinogenaemia was the most frequent bleeding disorder in the studied population [40 of 139 (28.78%)], followed by low prothrombin time (PT) [22 of 139 (15.83%)], thrombocytopenia [19 of 139 (13.67%)], hypofibrinogenaemia [18 of 139 (12.95)], prolonged activated partial thromboplastin time (7.91) and by thrombocytosis which was less frequent [6 of 139 (4.32%)]. Out of the six haemostatic disorders, only low PT was significantly associated with CD4 count (P=0.02). This study showed that bleeding disorders are very frequent in the HIV-infected patients studied. Low PT was significantly associated with CD4 count, hence it may be recommended to systematic screen for bleeding disorders in severe immune-depressed (CD4 ≤ 200) HIV-infected patients. PMID:24469390

  1. Radon-thoron discriminative measurements in the high natural radiation areas of southwestern Cameroon.

    Science.gov (United States)

    Saïdou; Tokonami, Shinji; Janik, Miroslaw; Samuel, Bineng Guillaume; Abdourahimi; Joseph Emmanuel, Ndjana Nkoulou I I

    2015-12-01

    Although indoor radon was initially measured in the uranium regions of Poli and Lolodorf using Electret Ionization Chambers, discriminative RADUET detectors were deployed in 70 houses of the high natural radiation areas of Bikoue and Ngombas in the uranium region of Lolodorf in Southwestern Cameroon. Radon and thoron concentrations were determined using Image-J and Microscope Methods for track evaluation. Radon and thoron concentrations follow lognormal distributions and ranged respectively from 27 ± 26 to 937 ± 5 Bq m(-3) and from 48 ± 40 to 700 ± 128 Bq m(-3). The arithmetic means of radon and thoron concentrations were found to be 92 ± 3 Bq m(-3) and 260 ± 13 Bq m(-3.) Less than 2% of houses have indoor radon above the reference level of 300 Bq m(-3) and 30% of houses have thoron concentrations above 300 Bq m(-3.) Inhalation doses due to radon and thoron range respectively between 0.6-17.7 mSv yr(-1) and 0.2-3 mSv yr(-1) with the mean values of 1.4 mSv yr(-1) and 1 mSv yr(-1). The contribution of indoor thoron to the total inhalation dose ranges between 15%- 78.5% with the mean value of 47%. Thus thoron cannot be neglected when assessing radiation dose.

  2. International Database of Volcanic Ash Impacts

    Science.gov (United States)

    Wallace, K.; Cameron, C.; Wilson, T. M.; Jenkins, S.; Brown, S.; Leonard, G.; Deligne, N.; Stewart, C.

    2015-12-01

    Volcanic ash creates extensive impacts to people and property, yet we lack a global ash impacts catalog to organize, distribute, and archive this important information. Critical impact information is often stored in ephemeral news articles or other isolated resources, which cannot be queried or located easily. A global ash impacts database would improve 1) warning messages, 2) public and lifeline emergency preparation, and 3) eruption response and recovery. Ashfall can have varying consequences, such as disabling critical lifeline infrastructure (e.g. electrical generation and transmission, water supplies, telecommunications, aircraft and airports) or merely creating limited and expensive inconvenience to local communities. Impacts to the aviation sector can be a far-reaching global issue. The international volcanic ash impacts community formed a committee to develop a database to catalog the impacts of volcanic ash. We identify three user populations for this database: 1) research teams, who would use the database to assist in systematic collection, recording, and storage of ash impact data, and to prioritize impact assessment trips and lab experiments 2) volcanic risk assessment scientists who rely on impact data for assessments (especially vulnerability/fragility assessments); a complete dataset would have utility for global, regional, national and local scale risk assessments, and 3) citizen science volcanic hazard reporting. Publication of an international ash impacts database will encourage standardization and development of best practices for collecting and reporting impact information. Data entered will be highly categorized, searchable, and open source. Systematic cataloging of impact data will allow users to query the data and extract valuable information to aid in the development of improved emergency preparedness, response and recovery measures.

  3. Volcanic lake systematics II. Chemical constraints

    Science.gov (United States)

    Varekamp, J.C.; Pasternack, G.B.; Rowe, G.L.

    2000-01-01

    A database of 373 lake water analyses from the published literature was compiled and used to explore the geochemical systematics of volcanic lakes. Binary correlations and principal component analysis indicate strong internal coherence among most chemical parameters. Compositional variations are influenced by the flux of magmatic volatiles and/or deep hydrothermal fluids. The chemistry of the fluid entering a lake may be dominated by a high-temperature volcanic gas component or by a lower-temperature fluid that has interacted extensively with volcanic rocks. Precipitation of minerals like gypsum and silica can strongly affect the concentrations of Ca and Si in some lakes. A much less concentrated geothermal input fluid provides the mineralized components of some more dilute lakes. Temporal variations in dilution and evaporation rates ultimately control absolute concentrations of dissolved constituents, but not conservative element ratios. Most volcanic lake waters, and presumably their deep hydrothermal fluid inputs, classify as immature acid fluids that have not equilibrated with common secondary silicates such as clays or zeolites. Many such fluids may have equilibrated with secondary minerals earlier in their history but were re-acidified by mixing with fresh volcanic fluids. We use the concept of 'degree of neutralization' as a new parameter to characterize these acid fluids. This leads to a classification of gas-dominated versus rock-dominated lake waters. A further classification is based on a cluster analysis and a hydrothermal speedometer concept which uses the degree of silica equilibration of a fluid during cooling and dilution to evaluate the rate of fluid equilibration in volcano-hydrothermal systems.

  4. Earthworm surface casting activity on slash-and-burn cropped land and in undisturbed Chromolaena odorata and young forest fallow in southern Cameroon

    NARCIS (Netherlands)

    Madong à Birang,; Hauser, S.; Brussaard, L.; Norgrove, L.

    2003-01-01

    The effect of slash-and-burn agriculture on earthworm surface cast deposition was assessed in 4-5 year old Chromolaena odorata (CHR) and young forest (YFOR). fallow (12-15 years) in the humid forest zone of southern Cameroon. In the villages Ngoungoumou (56.8% forest cover), Metet (39.5% forest cove

  5. Win-wins in forest product value chains? How governance impacts the sustainability of livelihoods based on non-timber forest products from Cameroon

    NARCIS (Netherlands)

    Ingram, V.J.

    2014-01-01

    Non-timber forest products (NTFPs) such as nuts, leaves, resins, barks and honey have medicinal, food, energy and cultural uses. This study examines eight such NTFP value chains from Cameroon, sold in markets locally and exported worldwide. It finds that these products are more valuable than previou

  6. Win-wins in forest product value chains? : how governance impacts the sustainability of livelihoods based on non-timber forest products from Cameroon

    NARCIS (Netherlands)

    Ingram, V.J.

    2014-01-01

    Non-timber forest products (NTFPs) such as nuts, leaves, resins, barks and honey from Cameroon have medicinal, food, energy and cultural uses. This study examines the arrangements governing eight such NTFP value chains, worth over 32 million US$ annually with around 34,000 people active, investigati

  7. Biome-specific effects of nitrogen and phosphorus on the photosynthetic characteristics of trees at a forest-savanna boundary in Cameroon

    NARCIS (Netherlands)

    Ferreira Domingues, Tomas; Ishida, F.Y.; Feldpausch, T.R.; Grace, John; Meir, Patrick; Saiz, Gustavo; Sene, Olivier; Schrodt, Franziska; Sonké, Bonaventure; Taedoumg, Herman; Veenendaal, E.M.; Lewis, Simon; Lloyd, Jon

    2015-01-01

    Photosynthesis/nutrient relationships of proximally growing forest and savanna trees were determined in an ecotonal region of Cameroon (Africa). Although area-based foliar N concentrations were typically lower for savanna trees, there was no difference in photosynthetic rates between the two vege

  8. An Exploratory Multi-Method Analysis of Cybercrime Perpetrators' Perceptions to Combat Cyber Crime in Sub Saharan Africa: The Case of Cameroon

    Science.gov (United States)

    Akuta, Eric Agwe-Mbarika

    2012-01-01

    The past decade has projected much of Africa as a haven for cybercrime perpetration. This view was widely evidenced in Cameroon, a country regarded as a miniature Africa due to its diverse socio-cultural, economic and political characteristics. In spite of efforts by government to curb cybercrime, the perpetration rate has not declined due to a…

  9. A lion population under threat : understanding lion (Panthera leo Linnaeus, 1758) ecology and human-lion interactions related to livestock predation in Waza National Park, Cameroon

    NARCIS (Netherlands)

    Tumenta, Pricelia Nyaekon

    2012-01-01

    Lions in Waza National Park Cameroon were studied with focus on lion ecology and the human-lion conflicts due to livestock predation. The number of adult lions has declined from 40-60 in 2002 to 14-21 in 2008, which represents a reduction of about 65% in 6 years. The human-livestock pressure on the

  10. The interactions of human mobility and farming systems and impacts on biodiversity and soil quality in the Western Highlands of Cameroon

    NARCIS (Netherlands)

    Tankou, Christopher Mubeteneh

    2013-01-01

    Population growth and the drop in the returns from the major cash crop (coffee) for small farmers are the main drivers that have influenced the farming systems and mobility of farmers in the Western Highlands of Cameroon (WHC). The main objective of this research activity was to determine the intera

  11. Technical Education and Vocational Training in Central Africa. Feasibility Survey of the Regional Development of Rapid Vocational Training: Cameroon, Central African Republic, Chad, and Gabon.

    Science.gov (United States)

    Organization for Rehabilitation through Training, Geneva (Switzerland).

    This final report is the result of a survey requested by the United States Agency for International Development (USAID) and undertaken by the Organization for Rehabilitation through Training (ORT) of four countries (Cameroon, Chad, Central African Republic, and Gabon) and a conference on vocational training sponsored by the Economic and Customs…

  12. Exploratory Data Analysis Using a Dedicated Visualization App: Looking for Patterns in Volcanic Activity

    Science.gov (United States)

    van Manen, S. M.; Chen, S.

    2015-12-01

    Here we present an App designed to visualize and identify patterns in volcanic activity during the last ten years. It visualizes VEI (volcanic explosivity index) levels, population size, frequency of activity, and geographic region, and is designed to address the issue of oversampling of data. Often times, it is difficult to access a large set of data that can be scattered at first glance and hard to digest without visual aid. This App serves as a model that solves this issue and can be applied to other data. To enable users to quickly assess the large data set it breaks down the apparently chaotic abundance of information into categories and graphic indicators: color is used to indicate the VEI level, size for population size within 5 km of a volcano, line thickness for frequency of activity, and a grid to pinpoint a volcano's latitude. The categories and layers within them can be turned on and off by the user, enabling them to scroll through and compare different layers of data. By visualising the data this way, patterns began to emerge. For example, certain geographic regions had more explosive eruptions than others. Another good example was that low frequency larger impact volcanic eruptions occurred more irregularly than smaller impact volcanic eruptions, which had a more stable frequencies. Although these findings are not unexpected, the easy to navigate App does showcase the potential of data visualization for the rapid appraisal of complex and abundant multi-dimensional geoscience data.

  13. The Online GVP/USGS Weekly Volcanic Activity Report: Providing Timely Information About Worldwide Volcanism

    Science.gov (United States)

    Mayberry, G. C.; Guffanti, M. C.; Luhr, J. F.; Venzke, E. A.; Wunderman, R. L.

    2001-12-01

    The awesome power and intricate inner workings of volcanoes have made them a popular subject with scientists and the general public alike. About 1500 known volcanoes have been active on Earth during the Holocene, approximately 50 of which erupt per year. With so much activity occurring around the world, often in remote locations, it can be difficult to find up-to-date information about current volcanism from a reliable source. To satisfy the desire for timely volcano-related information the Smithsonian Institution and US Geological Survey combined their strengths to create the Weekly Volcanic Activity Report. The Smithsonian's Global Volcanism Program (GVP) has developed a network of correspondents while reporting worldwide volcanism for over 30 years in their monthly Bulletin of the Global Volcanism Network. The US Geological Survey's Volcano Hazards Program studies and monitors volcanoes in the United States and responds (upon invitation) to selected volcanic crises in other countries. The Weekly Volcanic Activity Report is one of the most popular sites on both organization's websites. The core of the Weekly Volcanic Activity Report is the brief summaries of current volcanic activity around the world. In addition to discussing various types of volcanism, the summaries also describe precursory activity (e.g. volcanic seismicity, deformation, and gas emissions), secondary activity (e.g. debris flows, mass wasting, and rockfalls), volcanic ash hazards to aviation, and preventative measures. The summaries are supplemented by links to definitions of technical terms found in the USGS photoglossary of volcano terms, links to information sources, and background information about reported volcanoes. The site also includes maps that highlight the location of reported volcanoes, an archive of weekly reports sorted by volcano and date, and links to commonly used acronyms. Since the Weekly Volcanic Activity Report's inception in November 2000, activity has been reported at

  14. Climate change and its role in forecasting energy demand in buildings: A case study of Douala City, Cameroon

    Indian Academy of Sciences (India)

    Modeste Kameni Nematchoua; Gh R Roshan; René Tchinda; T Nasrabadi; Paola Ricciardi

    2015-02-01

    The foremost role of a building is to assure the comfort of its occupants. The thermal comfort of a building depends on the outdoor climate and requires a demand in energy for heating and cooling. In this paper, demand of energy (heating/cooling) in the buildings is discussed in Douala, Cameroon. Daily data of the last 40 years coming from five weather stations of Cameroon have been studied. Some forecasts have been carried out with 14 GCM models, associated to three future climate scenarios B1, A2, and A1B. However, only INCM3 of General Circulation Model (GCM) and A2 scenario was used. Energy demand in buildings is valued by HDD (heating degree day) and CDD (cooling degree day) indices. Obtained results show that the temperature evolves more quickly in dry season than in rainy season in Douala. Climate rise indicates an increasing demand of energy in the buildings for cooling. Global Douala heating shows a definite effect on outdoor comfort. From 2045 to 2075, the demand of energy for cooling will be superior to 50%. The total demand in energy for heating in the buildings is estimated to be 67.882 kcal from 1970 to 2000 and will be around 67.774 kcal from 2013 to 2043.

  15. Bacillus anthracis Diversity and Geographic Potential across Nigeria, Cameroon and Chad: Further Support of a Novel West African Lineage.

    Science.gov (United States)

    Blackburn, Jason K; Odugbo, Moses Ode; Van Ert, Matthew; O'Shea, Bob; Mullins, Jocelyn; Perreten, Vincent; Perrenten, Vincent; Maho, Angaya; Hugh-Jones, Martin; Hadfield, Ted

    2015-01-01

    Zoonoses, diseases affecting both humans and animals, can exert tremendous pressures on human and veterinary health systems, particularly in resource limited countries. Anthrax is one such zoonosis of concern and is a disease requiring greater public health attention in Nigeria. Here we describe the genetic diversity of Bacillus anthracis in Nigeria and compare it to Chad, Cameroon and a broader global dataset based on the multiple locus variable number tandem repeat (MLVA-25) genetic typing system. Nigerian B. anthracis isolates had identical MLVA genotypes and could only be resolved by measuring highly mutable single nucleotide repeats (SNRs). The Nigerian MLVA genotype was identical or highly genetically similar to those in the neighboring countries, confirming the strains belong to this unique West African lineage. Interestingly, sequence data from a Nigerian isolate shares the anthrose deficient genotypes previously described for strains in this region, which may be associated with vaccine evasion. Strains in this study were isolated over six decades, indicating a high level of temporal strain stability regionally. Ecological niche models were used to predict the geographic distribution of the pathogen for all three countries. We describe a west-east habitat corridor through northern Nigeria extending into Chad and Cameroon. Ecological niche models and genetic results show B. anthracis to be ecologically established in Nigeria. These findings expand our understanding of the global B. anthracis population structure and can guide regional anthrax surveillance and control planning.

  16. Bacillus anthracis Diversity and Geographic Potential across Nigeria, Cameroon and Chad: Further Support of a Novel West African Lineage.

    Directory of Open Access Journals (Sweden)

    Jason K Blackburn

    Full Text Available Zoonoses, diseases affecting both humans and animals, can exert tremendous pressures on human and veterinary health systems, particularly in resource limited countries. Anthrax is one such zoonosis of concern and is a disease requiring greater public health attention in Nigeria. Here we describe the genetic diversity of Bacillus anthracis in Nigeria and compare it to Chad, Cameroon and a broader global dataset based on the multiple locus variable number tandem repeat (MLVA-25 genetic typing system. Nigerian B. anthracis isolates had identical MLVA genotypes and could only be resolved by measuring highly mutable single nucleotide repeats (SNRs. The Nigerian MLVA genotype was identical or highly genetically similar to those in the neighboring countries, confirming the strains belong to this unique West African lineage. Interestingly, sequence data from a Nigerian isolate shares the anthrose deficient genotypes previously described for strains in this region, which may be associated with vaccine evasion. Strains in this study were isolated over six decades, indicating a high level of temporal strain stability regionally. Ecological niche models were used to predict the geographic distribution of the pathogen for all three countries. We describe a west-east habitat corridor through northern Nigeria extending into Chad and Cameroon. Ecological niche models and genetic results show B. anthracis to be ecologically established in Nigeria. These findings expand our understanding of the global B. anthracis population structure and can guide regional anthrax surveillance and control planning.

  17. Challenges in the Diagnosis and Management of Acquired Nontraumatic Urethral Strictures in Boys in Yaoundé, Cameroon

    Science.gov (United States)

    Mouafo Tambo, F. F.; Fossi kamga, G.; Kamadjou, C.; Mbouche, L.; Nwaha Makon, A. S.; Birraux, J.; Andze, O. G.; Angwafo, F. F.; Mure, P. Y.

    2016-01-01

    Introduction. Urethral strictures in boys denote narrowing of the urethra which can be congenital or acquired. In case of acquired strictures, the etiology is iatrogenic or traumatic and rarely infectious or inflammatory. The aim of this study was to highlight the diagnostic and therapeutic difficulties of acquired nontraumatic urethral strictures in boys in Yaoundé, Cameroon. Methodology. The authors report five cases of nontraumatic urethral strictures managed at the Pediatric Surgery Department of the YGOPH over a two-year period (November 2012–November 2014). In order to confirm the diagnosis of urethral stricture, all patients were assessed with both cystourethrography and urethrocystoscopy. Results. In all the cases the urethra was inflammatory with either a single or multiple strictures. The surgical management included internal urethrotomy (n = 1), urethral dilatation (n = 1), vesicostomy (n = 2), and urethral catheterization (n = 3). With a median follow-up of 8.2 months (4–16 months) all patients remained symptoms-free. Conclusion. The authors report the difficulties encountered in the diagnosis and management of nontraumatic urethral strictures in boys at a tertiary hospital in Yaoundé, Cameroon. The existence of an inflammatory etiology of urethral strictures in boys deserves to be considered. PMID:27239364

  18. Participatory Resource Mapping for Livelihood Values Derived from the Forest in Ekondo-Titi Subregion, Cameroon: A Gender Analysis

    Directory of Open Access Journals (Sweden)

    Daniel B. Etongo

    2012-01-01

    Full Text Available Increasingly, the multiplicity of products, services, and values, and the diversity of interests from different resource users and groups, is being acknowledged as vital for sustainable use. This calls for a shift from protection to sustainable use and to resource-user focus. The aim of this study is to identify the spatial occurrence of livelihood values through participatory resource mapping, their changes over time and alternatives for sustainable management. A participatory resource mapping study was conducted with local community, including important stakeholders in Ekondo-Titi subregion of Cameroon. The research technique which focused on gender revealed different patterns of forest resources and changes on the landscape. The study concludes that the importance of resources varies between men and women in Ekondo-Titi subregion of Cameroon, implying that resources may have multipurpose functions, but its exact role depends on the needs of the user groups that utilize them. The divergence of opinion on certain resources is a clear indication of preferences that are gender motivated. The study also revealed that the greatest impact of land use change is the conversion of forest land into agriculture.

  19. New insights in insect prey choice by chimpanzees and gorillas in southeast Cameroon: the role of nutritional value.

    Science.gov (United States)

    Deblauwe, Isra; Janssens, Geert P J

    2008-01-01

    The insect diet of chimpanzees and gorillas living at the northern periphery of the Dja Biosphere Reserve in southeast Cameroon and its nutritional contribution is described. We analyzed fecal samples and recorded additional evidence of insectivory. A detailed prey species list is presented for both apes. We carried out nutritional analyses (macronutrients, macro- and micro-minerals) on 11 important and eight nonimportant, but accessible, ant and termite prey species, and estimated the average nutrient intake/day through insects. Although gorillas ate insects more frequently, the average prey biomass intake/day by chimpanzees was twice that by gorillas. The lack of tool-use by gorillas cannot be the main reason for the small overlap of important prey species. Both apes did not seem to consume ant prey for one or more specific nutrients. Also other factors, such as medicinal use, should be considered. Termites, on the other hand, seemed to be selected for particular nutrients. Gorilla intake of the important termite prey, Cubitermes and Thoracotermes, met with estimated iron requirements. Their potential role as antidiarrheal treatment is as yet unclear. Chimpanzee intake of the important termite prey, Macrotermes spp., met with estimated manganese requirements and the protein intake/day (mean: 2 g/d) reached significant values (>20 g/d). To fully understand the importance of nutritional contributions of insects to ape diets in Cameroon, the chemical composition and nutrient intake of fruit and foliage in their diets should be investigated.

  20. Diabetes Mellitus: Indigenous naming, indigenous diagnosis and self-management in an African setting: the example from Cameroon

    Directory of Open Access Journals (Sweden)

    Awah Paschal K

    2009-02-01

    Full Text Available Abstract Background The objective was to examine how the indigenous naming, indigenous self-diagnosis and management of diabetes evolved with awareness in order to develop a socially oriented theoretical model for its care. Methods The data was collected through a one-year extended participant observation in Bafut, a rural health district of Cameroon. The sample consisted of 72 participants in a rural health district of Cameroon (men and women with type 2 diabetes. We used participant observation to collect data through focus group discussions, in depth interviews and fieldwork conversations. The method of analysis entailed a thick description, thematic analysis entailing constant comparison within and across FGD and across individual participants and content analysis. Results The core concepts identified were the evolution of names for diabetes and the indigenous diagnostic and self-management procedures. Participants fell into one of two naming typologies: (a Naming excluding any signs and symptoms of diabetes; (b naming including signs and symptoms of diabetes. Participants fell into two typologies of diagnostic procedures: (a those that use indigenous diagnostic procedures for monitoring and controlling diabetes outcomes and b those that had initially used it only for diagnosis and continued to use them for self management. These typologies varied according to how participants' awareness evolved and the impact on self-diagnosis and management. Conclusion The evolution of names for diabetes was an important factor that influenced the subsequent self-diagnosis and management of diabetes in both traditional and modern biomedical settings.

  1. Community-Based Tourism - Option for Forest-Dependent Communities in 1A IUCN Protected Areas? Cameroon Case Study

    Directory of Open Access Journals (Sweden)

    Burgin Shelley

    2014-01-01

    Full Text Available In developing countries, ‘exponential’ growth in IUCN protected lands has occurred in the last 25 years. Approximately 6% of protected areas are ‘Strict Nature Reserve[s]’ (1A with emphasis on conservation and strict restrictions on human access. Before Bakossi Forest Reserve (Cameroon had 1A protection, 95% of local families used the Reserve for their livelihood. They farmed cash crops, collected fire wood, timber, and food with incomes equivalent to US$35,000/annually/family. Post-protection, the Reserve’s local communities lacked support to develop alternative livelihoods, and 75% reported being intercepted illegally trespassing by Reserve guards. Without illegal activity economic impacts would have been substantially greater. Protection has also meant foregone national income from timber and coffee exports. We used Bakossi Forest Reserve as a case study to identify issues facing local communities excluded from the Reserve that traditionally provided their livelihood. We also investigated potential alternative family livelihoods based on critical evaluation of the literature. We identified ‘exceptional’ community-based tourism potential. We also found that Cameroon was the first African country to develop community-based forestry with the dual roles of conservation and poverty alleviation. Using this model, community-based tourism could be a cost-effectively initiative to deliver the same dual roles as community-based forestry.

  2. Using Spatial Density to Characterize Volcanic Fields on Mars

    Science.gov (United States)

    Richardson, J. A.; Bleacher, J. E.; Connor, C. B.; Connor, L. J.

    2012-01-01

    We introduce a new tool to planetary geology for quantifying the spatial arrangement of vent fields and volcanic provinces using non parametric kernel density estimation. Unlike parametricmethods where spatial density, and thus the spatial arrangement of volcanic vents, is simplified to fit a standard statistical distribution, non parametric methods offer more objective and data driven techniques to characterize volcanic vent fields. This method is applied to Syria Planum volcanic vent catalog data as well as catalog data for a vent field south of Pavonis Mons. The spatial densities are compared to terrestrial volcanic fields.

  3. Insight of the fusion behavior of volcanic ash: Implications for Volcanic ash Hazards to Aircraft Safety

    Science.gov (United States)

    Song, Wenjia; Hess, Kai-Uwe; Küppers, Ulrich; Scheu, Bettina; Cimarelli, Corrado; Lavallée, Yan; Sohyun, Park; Gattermann, Ulf; Müller, Dirk; Dingwell, Donald Bruce

    2014-05-01

    The interaction of volcanic ash with jet turbines during via ingestion of ash into engines operating at supra-volcanic temperatures is widely recognized as a potentially fatal hazard for jet aircraft. In the past 12 years, more than 60 modern jet airplanes, mostly jumbo jets, have been damaged by drifting clouds of volcanic ash that have contaminated air routes and airport facilities. Seven of these encounters are known to have caused in flight loss of engine power to jumbo jets carrying a total of more than 2000 passengers. The fusibility of volcanic ash is believed to impact strongly its deposition in the hotter parts of jet engines. Despite this, explicit investigation of ash sintering using standardized techniques is in its infancy. Volcanic ash may vary widely in its physical state and chemical composition between and even within explosive volcanic eruptions. Thus a comparative study of the fusibility of ash which involves a standard recognized techniques would be highly desirable. In this work, nine samples of fine ash, deposited from co-pyroclastic offrom nine different volcanoes which cover a broad range of chemical composition, were investigated. Eight of them were collected from 2001-2009 eruptions. Because of the currently elevated level of eruptive activity and its potential hazards to aircraft safety and the remaining one sample was collected from a 12,121 ± 114 yr B.P. eruption. We used the method of accessing the behavior of deposit-forming impurities in high temperature boiler plants on the basis of observations of the change in shape and size of a cylindrical coal ash to study the fusion phenomena as well as determine the volcanic ash melting behavior by defining four characteristic temperatures (shrinkage temperature, deformation temperature, hemispherical temperature, and flow temperature) by means of heating microscope instrument and different thermal analysis methods. Here, we find that there are similar sticking ability and flow behavior of

  4. Electrical charging of ash in Icelandic volcanic plumes

    CERN Document Server

    Aplin, Karen L; Nicoll, Keri A

    2014-01-01

    The existence of volcanic lightning and alteration of the atmospheric potential gradient in the vicinity of near-vent volcanic plumes provides strong evidence for the charging of volcanic ash. More subtle electrical effects are also visible in balloon soundings of distal volcanic plumes. Near the vent, some proposed charging mechanisms are fractoemission, triboelectrification, and the so-called "dirty thunderstorm" mechanism, which is where ash and convective clouds interact electrically to enhance charging. Distant from the vent, a self-charging mechanism, probably triboelectrification, has been suggested to explain the sustained low levels of charge observed on a distal plume. Recent research by Houghton et al. (2013) linked the self-charging of volcanic ash to the properties of the particle size distribution, observing that a highly polydisperse ash distribution would charge more effectively than a monodisperse one. Natural radioactivity in some volcanic ash could also contribute to self-charging of volcan...

  5. Small instrument to volcanic seismic signals

    Science.gov (United States)

    Carreras, Normandino; Gomariz, Spartacus; Manuel, Antoni

    2014-05-01

    Currently, the presence of volcanoes represents a threat to their local populations, and for this reason, scientific communities invest resources to monitor seismic activity of an area, and to obtain information to identify risk situations. To perform such monitoring, it can use different general purpose acquisition systems commercially available, but these devices do not meet to the specifications of reduced dimensions, low weight, low power consumption and low cost. These features allow the system works in autonomous mode for a long period of time, and it makes easy to be carried and to be installed. In the line of designing a volcanic acquisition system with the previously mentioned specifications, exists the Volcanology Department of CSIC, developers of a system with some of these specifications. The objective of this work is to improve the energy consumption requirements of the previous system, providing three channels of data acquisition and with the possibility to transmit data acquisition via radio frequency to a base station, allowing operation it in remote mode. The developed acquisition system consists of three very low-power acquisition modules of Texas Instruments (ADS1246), and this is designed to capture information of the three coordinate axes. A microprocessor also of Texas Instruments (MSP430F5438) is used to work in low-power, due to it is ready to run this consumption and also takes advantage the power save mode in certain moments when system is not working. This system is configurable by serial port, and it has a SD memory to storage data. Contrast to the previous system, it has a RF communication module incorporated specially to work in remote mode of Lynx (YLX-TRM8053-025-05), and boasts also with a GPS module which keeps the time reference synchronized with module of SANAV (GM-1315LA). Thanks to this last selection of components, it is designed a small system about 106 x 106 mm. Assuming that the power supply system is working during all the

  6. Quaternary volcanism in the Acambay graben, Mexican Volcanic Belt: Re-evaluation for potential volcanic danger in central Mexico

    Science.gov (United States)

    Aguirre-Diaz, G. J.; Pedrazzi, D.; Lacan, P.; Roldan-Quintana, J.; Ortuňo, M.; Zuniga, R. R.; Laurence, A.

    2015-12-01

    The Mexican Volcanic Belt (MVB) is best known for the major active stratovolcanoes, such as Popocatépetl, Citlaltépetl and Colima. The most common stratovolcanoes in this province are modest-size cones with heights of 800 to 1000 m. Examples are Tequila, Sangangüey, Las Navajas, Culiacán, La Joya, El Zamorano, Temascalcingo and Altamirano; these last two were formed within the Acambay Graben in central MVB. The Acambay graben (20 x 70 km) is 100 km to the NW of Mexico City, with E-W trending seismically active normal faults; in particular the Acambay-Tixmadejé fault related to a mB =7 earthquake in 1912. Within the graben there are many volcanic structures, including calderas, domes, cinder cones and stratovolcanoes; Temascalcingo and Altamirano are the largest, with about 800 and 900 m heights, respectively. Temascalcingo is mostly composed of dacitic lavas and block and ash flow deposits. Includes a 3 x 2.5 km summit caldera and a magmatic sector collapse event with the associated debris avalanche deposit. 14C ages of 37-12 ka correspond to the volcano's latest phases that produced pyroclastic deposits. A major plinian eruption formed the San Mateo Pumice with an age of <20 Ka. Altamirano volcano is poorly studied; it is andesitic-dacitic, composed of lavas, pyroclastic flow deposits, and pumice fallouts. Morphologically is better preserved than Temascalcingo, and it should be younger. 14C ages of 4.0-2.5 ka were performed in charcoal within pyroclastic flow deposits that apparently were erupted from Altamirano. An undated 3 m thick pumice fallout on the flanks of Altamirano volcano could be also Holocene. It represents a major explosive event. The relatively young ages found in volcanic deposits within the Acambay graben raise the volcanic danger level in this area, originally thought as an inactive volcanic zone. The two major volcanoes, Temascalcingo and Altamirano, should be considered as dormant volcanoes that could restart activity at any time. We

  7. Noise-induced variability of volcanic extrusions

    Science.gov (United States)

    Alexandrov, D. V.; Bashkirtseva, I. A.; Ryashko, L. B.

    2016-11-01

    Motivated by important physical applications, we study a non-linear dynamics of volcanic extrusions on the basis of a simple pressure-mass flow model. We demonstrate that the deterministic phase portrait represents either the bulbous-type curves or closed paths stretched to their left depending on the initial conditions. The period of phase trajectories therewith increases when the pressure drop between the conduit top and bottom compensates the lava column pressure in it. Stochastic forcing changes the system dynamics drastically. We show that a repetitive scenario of volcanic behaviour with intermittency of stochastic oscillations of different extrusion amplitudes and frequencies appears in the presence of noises. As this takes place, the mean values of interspike intervals characterizing the system periodicity have a tendency to grow with increasing the noise intensity. The probability distribution functions confirming this dynamic behaviour are constructed.

  8. Learning to recognize volcanic non-eruptions

    Science.gov (United States)

    Poland, Michael P.

    2010-01-01

    An important goal of volcanology is to answer the questions of when, where, and how a volcano will erupt—in other words, eruption prediction. Generally, eruption predictions are based on insights from monitoring data combined with the history of the volcano. An outstanding example is the A.D. 1980–1986 lava dome growth at Mount St. Helens, Washington (United States). Recognition of a consistent pattern of precursors revealed by geophysical, geological, and geochemical monitoring enabled successful predictions of more than 12 dome-building episodes (Swanson et al., 1983). At volcanic systems that are more complex or poorly understood, probabilistic forecasts can be useful (e.g., Newhall and Hoblitt, 2002; Marzocchi and Woo, 2009). In such cases, the probabilities of different types of volcanic events are quantified, using historical accounts and geological studies of a volcano's past activity, supplemented by information from similar volcanoes elsewhere, combined with contemporary monitoring information.

  9. Connecting Io's volcanic activity to the Io plasma torus: comparison of Galileo/NIMS volcanic and ground-based torus observations

    Science.gov (United States)

    Magalhaes, F. P.; Lopes, R. M. C.; Rathbun, J. A.; Gonzalez, W. D.; Morgenthaler, J. P.; Echer, E.; Echer, M. P. D. S.

    2015-12-01

    Io, the innermost of the Jupiter's four Galilean moons, is a remarkable object in the Solar System, due to its intense and energetic volcanic activity. The volcanic sulfur and oxygen in Io's tenuous atmosphere escapes forming an extended neutral cloud around Io and Jupiter. Subsequently, by ionization and pickup ions, a ring of charged particles encircling Jupiter is created, forming the Io plasma torus. Considering this scenario, it is reasonable to expect that the Io plasma torus should be affected by changes in Io's volcanism. Interactions between Io and the Jovian environment is unique and yet not very well understood. Here we present two sets of observations. One from the Galileo Near-Infrared Imaging Spectrograph (NIMS) instrument, which obtained spectral image cubes between 0.7 and 5.2 microns. The other dataset is from ground-based observations of the [SII] 6731 Å emission lines from the Io plasma torus, obtained at McMath-Pierce Solar Telescope, at Kitt Peak. Our dataset from the [SII] 6731 Å emission lines cover more years than the one from the NIMS data. The years presented in this work for a comparative study are from 1998 through 2001. Using the NIMS instrument we were able to identify which volcanoes were active and measure their level of activity. From the [SII] 6731 Å emission lines we were able to trace the densest part of the torus and also the brightness of both ansa. By comparing the results from the Galileo instrument and the ground-based observations, we are exploring how the Io plasma torus responds to large eruptions from Io. We aim with this study to help improve our understanding of this complex coupled system, Jupiter-Io.

  10. Characterization of volcanic ash from the 2011 Grímsvötn eruption by means of single-particle analysis

    Science.gov (United States)

    Lieke, K. I.; Kristensen, T. B.; Korsholm, U. S.; Sørensen, J. H.; Kandler, K.; Weinbruch, S.; Ceburnis, D.; Ovadnevaite, J.; O'Dowd, C. D.; Bilde, M.

    2013-11-01

    This work focuses on transport and properties of ash from the Icelandic volcano Grímsvötn that erupted in spring 2011. Atmospheric transport of volcanic ash from the eruption was simulated using the Danish Emergency Response Model of the Atmosphere (DERMA). The arrivals of volcanic particles were detected on-line at Mace Head at the West coast of Ireland during volcanic plume advection identified by high resolution time of flight aerosol mass spectrometry (HR-ToF AMS). Based on DERMA information aerosol particles were collected in Copenhagen, Denmark, before predicted arrival of the ash plume and during a period where ash was present in the air. Analysis of the meteorological conditions shows that the particles collected before arrival of the volcanic ash may serve as a good reference sample allowing identification of significant changes in ambient aerosol properties during the volcanic ash event over Copenhagen. Using single particle analysis in scanning electron microscopy (SEM), data on structure, chemical composition, size and morphology of individual volcanic ash particles from the Grímsvötn eruption after atmospheric transport to Scandinavia are provided. Particles were sliced with Focused Ion Beam (FIB). Element mappings from cross-sections through collected volcanic ash particles reveal inhomogeneous distributions of the elements K, Mg, Fe and Ti.

  11. The Zuni-Bandera Volcanic Field, NM: An Analog for Exploring Planetary Volcanic Terrains

    Science.gov (United States)

    Bleacher, J. E.; Garry, W. B.; Zimbelman, J. R.; Crumpler, L. S.; Aubele, J. C.

    2010-12-01

    The Zuni-Bandera volcanic field, near Grants, New Mexico, is comprised of volcanic deposits from several basaltic eruptions during the last million years. This vent field exhibits a diverse group of coalesced lava flows and displays well-preserved volcanic features including a’a and pahoehoe flows, collapsed lava tubes, cinder cones and low shields. The McCartys flow is a 48-km long inflated basalt flow and is the youngest in the field at around 3000 years old. Over the last three years we have used the Zuni-Bandera volcanic field, and the McCartys flow in particular, as a terrestrial analog for exploring planetary volcanic fields, and understanding the role of lava sheet inflation in flow field development. We have conducted three different styles of analog tests, 1) basic field science focused on understanding lava sheet inflation, 2) mission operations tests related to EVA design and real-time modification of traverse plans, and 3) science enabling technology tests. The Zuni-Bandera field is an ideal location for each style of analog test because it provides easy access to a diverse set of volcanic features with variable quality of preservation. However, many limitations must also be considered in order to maximize lessons learned. The McCartys flow displays well-preserved inflation plateaus that rise up to 15 m above the surrounding field. The preservation state enables textures and morphologies indicative of this process to be characterized. However, the pristine nature of the flow does not compare well with the much older and heavily modified inflated flows of Mars and the Moon. Older flows west of McCartys add value to this aspect of analog work because of their degraded surfaces, development of soil horizons, loose float, and limited exposure of outcrops, similar to what might be observed on the Moon or Mars. EVA design tests and science enabling technology tests at the Zuni-Bandera field provide the opportunity to document and interpret the relationships

  12. Taos Plateau Volcanic Project: A Vehicle for Integration of Concepts in Igneous Petrology

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    Henry, D.; Dutrow, B.

    2003-12-01

    Integrating concepts of igneous petrology is generally a challenge, but can be effective in the context of a project based on actual field, geochemical and geochronological data. The final lab project in the igneous portion of petrology involves a series of volcanic and associated rock samples that were collected from the Taos Plateau Volcanic Field, New Mexico, USA. Samples were collected over an area of several tens of km2 throughout the Plateau and represent a spatially and temporally correlated rock suite related to continental rifting. Rift-related magmatism encompasses much of the diversity of terrestrial magma types. Compositions of mafic magmas range from tholeiite to some of the most silica-undersaturated magmas found on the continents. Large effusive eruptions from fissures are typical of some rifts, whereas others may be dominated by central vent cones or even silicic caldera complexes. The injection of mantle-derived magma in extending crust may have a profound effect on the rheology of the crust and, therefore, the style of deformation associated with extension. Most of these aspects of rift volcanism and a wide range of mafic to silicic magma compositions are represented in the Rio Grande rift and the volcanic rocks of the Taos Plateau. In addition, much published data exists for whole rock and trace element geochemistry as well as geochronology. Rock samples and associated information are presented so that the student must integrate multiple lines of evidence, petrographic, petrologic, geochemical and geochronological data in a geospatial framework, to establish a geologic history of the region. The student must also draw on skills learned in mineralogy and structural geology furthering core geoscience education. Subsequent to the petrology course, the students visit the Taos Plateau Volcanic Field during their required field camp, thus reinforcing the linkage between the classroom setting and geologic reality.

  13. Volcanic alert system (VAS) developed during the 2011-2014 El Hierro (Canary Islands) volcanic process

    Science.gov (United States)

    García, Alicia; Berrocoso, Manuel; Marrero, José M.; Fernández-Ros, Alberto; Prates, Gonçalo; De la Cruz-Reyna, Servando; Ortiz, Ramón

    2014-06-01

    The 2011 volcanic unrest at El Hierro Island illustrated the need for a Volcanic Alert System (VAS) specifically designed for the management of volcanic crises developing after long repose periods. The VAS comprises the monitoring network, the software tools for analysis of the monitoring parameters, the Volcanic Activity Level (VAL) management, and the assessment of hazard. The VAS presented here focuses on phenomena related to moderate eruptions, and on potentially destructive volcano-tectonic earthquakes and landslides. We introduce a set of new data analysis tools, aimed to detect data trend changes, as well as spurious signals related to instrumental failure. When data-trend changes and/or malfunctions are detected, a watchdog is triggered, issuing a watch-out warning (WOW) to the Monitoring Scientific Team (MST). The changes in data patterns are then translated by the MST into a VAL that is easy to use and understand by scientists, technicians, and decision-makers. Although the VAS was designed specifically for the unrest episodes at El Hierro, the methodologies may prove useful at other volcanic systems.

  14. Venus volcanism: initial analysis from magellan data.

    Science.gov (United States)

    Head, J W; Campbell, D B; Elachi, C; Guest, J E; McKenzie, D P; Saunders, R S; Schaber, G G; Schubert, G

    1991-04-12

    Magellan images confirm that volcanism is widespread and has been fimdamentally important in the formation and evolution of the crust of Venus. High-resolution imaging data reveal evidence for intrusion (dike formation and cryptodomes) and extrusion (a wide range of lava flows). Also observed are thousands of small shield volcanoes, larger edifices up to several hundred kilometers in diameter, massive outpourings of lavas, and local pyroclastic deposits. Although most features are consistent with basaltic compositions, a number of large pancake-like domes are morphologically similar to rhyolite-dacite domes on Earth. Flows and sinuous channels with lengths of many hundreds of kilometers suggest that extremely high effusion rates or very fluid magmas (perhaps komatiites) may be present. Volcanism is evident in various tectonic settings (coronae, linear extensional and compressional zones, mountain belts, upland rises, highland plateaus, and tesserae). Volcanic resurfacing rates appear to be low (less than 2 Km(3)/yr) but the significance of dike formation and intrusions, and the mode of crustal formation and loss remain to be established.

  15. Minerogenesis of volcanic caves of Kenya.

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    Rossi Antonio

    2003-01-01

    Full Text Available Kenya is one of the few countries in which karst cavities are scarce with respect to volcanic ones, which are widespread throughout the whole country. The great variability in lava composition allowed the evolution of very different cavities, some of which are amongst the largest lava tubes of the world. As normal for such a kind of cave, the hosted speleothems and cave minerals are scarce but important from the minerogenetic point of view. Anyway up to present no specific mineralogical research have been carried out therein. During the 8th International Symposium on Volcanospeleology, held in Nairobi in February 1998, some of the most important volcanic caves of Kenya have been visited and their speleothems and/or chemical deposits sampled: most of them were related to thick guano deposits once present inside these cavities. Speleothems mainly consisted of opal or gypsum, while the deposits related to guano often resulted in a mixture of sulphates and phosphates. The analyses confirmed the great variability in the minerogenetic mechanisms active inside the volcanic caves, which consequently allow the evolution of several different minerals even if the total amount of chemical deposit is scarce. Among the observed minerals kogarkoite, phillipsite and hydroxyapophyllite, must be cited because they are new cave minerals not only for the lava tubes of Kenya, but also for the world cave environment. The achieved results are compared with the available random data from previous literature in order to allow an updated overview on the secondary cave minerals of Kenya.

  16. Venus volcanism: Initial analysis from Magellan data

    Science.gov (United States)

    Head, J.W.; Campbell, D.B.; Elachi, C.; Guest, J.E.; Mckenzie, D.P.; Saunders, R.S.; Schaber, G.G.; Schubert, G.

    1991-01-01

    Magellan images confirm that volcanism is widespread and has been fundamentally important in the formation and evolution of the crust of Venus. High-resolution imaging data reveal evidence for intrusion (dike formation and cryptodomes) and extrusion (a wide range of lava flows). Also observed are thousands of small shield volcanoes, larger edifices up to several hundred kilometers in diameter, massive outpourings of lavas, and local pyroclastic deposits. Although most features are consistent with basaltic compositions, a number of large pancake-like domes are morphologically similar to rhyolite-dacite domes on Earth. Flows and sinuous channels with lengths of many hundreds of kilometers suggest that extremely high effusion rates or very fluid magmas (perhaps komatiites) may be present. Volcanism is evident in various tectonic settings (coronae, linear extensional and compressional zones, mountain belts, upland rises, highland plateaus, and tesserae). Volcanic resurfacing rates appear to be low (less than 2 km3/yr) but the significance of dike formation and intrusions, and the mode of crustal formation and loss remain to be established.

  17. Real time retrieval of volcanic cloud particles and SO2 by satellite using an improved simplified approach

    Science.gov (United States)

    Pugnaghi, Sergio; Guerrieri, Lorenzo; Corradini, Stefano; Merucci, Luca

    2016-07-01

    Volcanic plume removal (VPR) is a procedure developed to retrieve the ash optical depth, effective radius and mass, and sulfur dioxide mass contained in a volcanic cloud from the thermal radiance at 8.7, 11, and 12 µm. It is based on an estimation of a virtual image representing what the sensor would have seen in a multispectral thermal image if the volcanic cloud were not present. Ash and sulfur dioxide were retrieved by the first version of the VPR using a very simple atmospheric model that ignored the layer above the volcanic cloud. This new version takes into account the layer of atmosphere above the cloud as well as thermal radiance scattering along the line of sight of the sensor. In addition to improved results, the new version also offers an easier and faster preliminary preparation and includes other types of volcanic particles (andesite, obsidian, pumice, ice crystals, and water droplets). As in the previous version, a set of parameters regarding the volcanic area, particle types, and sensor is required to run the procedure. However, in the new version, only the mean plume temperature is required as input data. In this work, a set of parameters to compute the volcanic cloud transmittance in the three quoted bands, for all the aforementioned particles, for both Mt. Etna (Italy) and Eyjafjallajökull (Iceland) volcanoes, and for the Terra and Aqua MODIS instruments is presented. Three types of tests are carried out to verify the results of the improved VPR. The first uses all the radiative transfer simulations performed to estimate the above mentioned parameters. The second one makes use of two synthetic images, one for Mt. Etna and one for Eyjafjallajökull volcanoes. The third one compares VPR and Look-Up Table (LUT) retrievals analyzing the true image of Eyjafjallajökull volcano acquired by MODIS aboard the Aqua satellite on 11 May 2010 at 14:05 GMT.

  18. [Characteristics of murder and attempted murder in Cameroon. Study based on expert psychiatric court reports].

    Science.gov (United States)

    Mbassa Menick, D

    2009-06-01

    The purpose of this study was to describe the sociodemographic, psychopathologic and criminological features associated with homicide based on review of expert psychiatric court reports describing murder and attempted murder perpetrators examined at Jamot Hospital in Yaoundé, Cameroon. The study cohort comprised reports describing 12 offenders who were examined at the request of ajudge or public prosecutor from March 1, 2002 to July 31, 2006. There were 8 men (66.7%) and 4 women (33.3%) with a mean age of 18.3 years (range, 17 to 43 years). In 8 cases the criminal act coincided with a difficult period in the offender's life. In the remaining 4 cases the act could not be linked to a specific life event. Assaults were carried out by strangulation, battery, or stabbing (knifes or machetes) in 87.5% of cases and occurred at the victim's home in 68.8% of cases. The main mental disorders diagnosed using the ICD-10 classification were schizophrenia in 41.7% of cases (n = 5), chronic delirium in 25.0% (n = 3), and personality disorder in 8.3 % (n = 1). Nine offenders (75.0%) had a history of mental disorder including 8 within at least six months preceding the assault. Four offenders had already received psychiatric treatment including 2 who required hospitalization following one or more episodes of psychotic decompensation. There were a total of 16 victims including 14 that died and 2 that were seriously wounded but survived thanks to prompt medical attention. The victims included 8 males and 8 females with 11 children (68.7%) and 5 adults (31.3%). In the child group 9 victims died (81.8%) and 2 survived (18.2%). Except one 17-year-old teenager, the 6 female and 3 male child victims were between the ages of 18 months and 8 years. The adult victims included 1 female and 4 males. The main findings of this study were the high incidence of mental disease, especially schizophrenics (66.7%), associated with homicide and the high number of child victims (62.5%). The first

  19. Measurement of radium isotope activities in reservoir and spring water in the Cameroon Central Region

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    Rose Lydie Marie

    2015-09-01

    Full Text Available Purpose: To determine the activities of 226Ra and 228Ra in the reservoir and spring water samples respectively during the dry and the rainy seasons; and to calculate the annual intake Ii (Bq/y for each type of water samples. Methods: Using both well calibrated Canberra NaI(Tl and HPGe detector systems, it was possible to determine the average specific activity of those radium’s isotopes in water samples which were collected in 2010, from Reservoirs and springs in Cameroon central region including Ngoaekelle, Minboman, Etoudi and Njoungolo. Results: The average specific activity values obtained for 226Ra and 228Ra in reservoir water samples were 8.76 ± 3.50 BqL-1 and 0.64 ± 0.28 BqL-1 during the dry season and, 8.24 ±3.48 BqL-1 and 0.58 ± 0.24 BqL-1 during the rainy season respectively. For spring water, the average values were 3.50 ± 0.63 BqL-1 and below 0.0002 BqL-1 (detection limit of 228Ra in water during the dry season; 3.20 ± 0.60 BqL-1 and below 0.0002 BqL-1 (detection limit of 228Ra in water during the rainy season respectively. Assuming that the volume of drinking water for adult is 2.5 litres per day, the average annual intakes of 226Ra and 228Ra through ingestion in these water samples were 7702 Bq/y and 575 Bq/y for reservoir water; 2993 Bq/y and < 0.25 for spring water respectively. Conclusion: The results have indicated that the annual intake by the population of sampling region as a result of 226Ra in these drinking waters is 7.7 × 103Bq/y more than the maximum limit fixed by ICRP which is 7 × 103 Bq/y. There is a need for regular monitoring the radiological water quality aspect in this region.

  20. Spatio-temporal patterns and landscape-associated risk of Buruli ulcer in Akonolinga, Cameroon.

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    Jordi Landier

    2014-09-01

    Full Text Available Buruli ulcer (BU is an extensively damaging skin infection caused by Mycobacterium ulcerans, whose transmission mode is still unknown. The focal distribution of BU and the absence of interpersonal transmission suggest a major role of environmental factors, which remain unidentified. This study provides the first description of the spatio-temporal variations of BU in an endemic African region, in Akonolinga, Cameroon. We quantify landscape-associated risk of BU, and reveal local patterns of endemicity.From January 2002 to May 2012, 787 new BU cases were recorded in 154 villages of the district of Akonolinga. Incidence per village ranged from 0 (n = 59 villages to 10.4 cases/1000 person.years (py; median incidence was 0.4 cases/1,000 py. Villages neighbouring the Nyong River flood plain near Akonolinga town were identified as the highest risk zone using the SPODT algorithm. We found a decreasing risk with increasing distance to the Nyong and identified 4 time phases with changes in spatial distribution. We classified the villages into 8 groups according to landscape characteristics using principal component analysis and hierarchical clustering. We estimated the incidence ratio (IR associated with each landscape using a generalised linear model. BU risk was highest in landscapes with abundant wetlands, especially cultivated ones (IR = 15.7, 95% confidence interval [95%CI] = 15.7[4.2-59.2], and lowest in reference landscape where primary and secondary forest cover was abundant. In intermediate-risk landscapes, risk decreased with agriculture pressure (from IR[95%CI] = 7.9[2.2-28.8] to 2.0[0.6-6.6]. We identified landscapes where endemicity was stable and landscapes where incidence increased with time.Our study on the largest series of BU cases recorded in a single endemic region illustrates the local evolution of BU and identifies the Nyong River as the major driver of BU incidence. Local differences along the river are explained by wetland

  1. Assessing the accessibility of HIV care packages among tuberculosis patients in the Northwest Region, Cameroon

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    Miguel San

    2010-03-01

    Full Text Available Abstract Background Tuberculosis (TB and human immunodeficiency virus (HIV co-infection is a major source of morbidity and mortality globally. The World Health Organization (WHO has recommended that HIV counselling and testing be offered routinely to TB patients in order to increase access to HIV care packages. We assessed the uptake of provider-initiated testing and counselling (PITC, antiretroviral (ART and co-trimoxazole preventive therapies (CPT among TB patients in the Northwest Region, Cameroon. Methods A retrospective cohort study using TB registers in 4 TB/HIV treatment centres (1 public and 3 faith-based for patients diagnosed with TB between January 2006 and December 2007 to identify predictors of the outcomes; HIV testing/serostatus, ART and CPT enrolment and factors that influenced their enrolment between public and faith-based hospitals. Results A total of 2270 TB patients were registered and offered pre-HIV test counselling; 2150 (94.7% accepted the offer of a test. The rate of acceptance was significantly higher among patients in the public hospital compared to those in the faith-based hospitals (crude OR 1.97; 95% CI 1.33 - 2.92 and (adjusted OR 1.92; 95% CI 1.24 - 2.97. HIV prevalence was 68.5% (1473/2150. Independent predictors of HIV-seropositivity emerged as: females, age groups 15-29, 30-44 and 45-59 years, rural residence, previously treated TB and smear-negative pulmonary TB. ART uptake was 50.3% (614/1220 with 17.2% (253/1473 of missing records. Independent predictors of ART uptake were: previously treated TB and extra pulmonary TB. Finally, CPT uptake was 47.0% (524/1114 with 24% (590/1114 of missing records. Independent predictors of CPT uptake were: faith-based hospitals and female sex. Conclusion PITC services are apparently well integrated into the TB programme as demonstrated by the high testing rate. The main challenges include improving access to ART and CPT among TB patients and proper reporting and monitoring of

  2. Antimicrobial and toxicological activities of five medicinal plant species from Cameroon Traditional Medicine

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    Njouendou Abdel J

    2011-08-01

    methanolic extracts of Phyllanthus muellerianus and Piptadeniastrum africana indicated that these two plants were not toxic. At the dose of 4 g/kg body weight, kidney and liver function tests indicated that these two medicinal plants induced no adverse effect on these organs. Conclusion These results showed that, all these plant's extracts can be used as antimicrobial phytomedicines which can be therapeutically used against infections caused by multiresistant agents. Phyllanthus muellerianus, Piptadeniastum africana, antimicrobial, acute toxicity, kidney and liver function tests, Cameroon Traditional Medicine

  3. Operational barriers to the implementation of multidrug therapy and leprosy elimination in Cameroon

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    Nsagha Dickson

    2009-01-01

    Full Text Available Background: The World Health Organization targeted to eliminate leprosy from the world with multidrug therapy (MDT by 2000. But, leprosy remains a problem in Essimbiland of Menchum Division of Cameroon, with a prevalence of 1.7/10,000 and high rate of case detection in children. Aims: To assess knowledge and practices on the cure of leprosy, treatment duration, drug availability and problems faced by leprosy patients acquiring drugs in order to enhance MDT implementation and leprosy elimination in Menchum and Boyo divisions. Methods: Observational study in which a structured questionnaire was administered to leprosy patients, their contacts and a control group. Results: 480 respondents were interviewed and 405 (84.8% (95% confidence interval [CI]: 81.6-87.2% knew that leprosy can be cured. These respondents comprised 166 (92.2% of 180 contacts, 129 (93.5% of 138 patients and 110 (67.9% of 162 controls. Two hundred and fourteen (44.6% (95% CI: 40.1-48.9% respondents knew that leprosy treatment is free, comprising of 110 (51.4% patients, 99 (46.3% contacts and five (2.3% controls. A statistically significant difference in the knowledge on free treatment of leprosy was found to exist between leprosy patients, contacts and controls, with leprosy patients having a better knowledge (79.71% (95% CI: 73-86.42%, followed by contacts (55.0% (95% CI: 47.73-62.26% and controls (3.1% (95% CI: 0.43-5.77% (P = 0.00. Pertinent problems faced by patients in getting MDT included distant health facilities and poor road network (91[19.0%], lack of confidence in treatment (56 [11.7%], MDT shortage (45 [9.4%], few health facilities (52 [10.8%], gratification demands (25 [5.2%], disturbance from other illnesses (24 [5.0], ignorance (21 [4.4%] and poor relationship with nurses (24 [5.0%]. Conclusion: Patients still face problems in getting free MDT. Better MDT implementation and leprosy elimination strategies are proposed.

  4. High mosquito burden and malaria transmission in a district of the city of Douala, Cameroon

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    Antonio-Nkondjio Christophe

    2012-10-01

    Full Text Available Abstract Background Rapid demographic growth in Douala city, Cameroon, has resulted in profound ecological and environmental changes. Although demographic changes can affect anopheline mosquito breeding sites, there is a lack of understanding about the epidemiological impact that such changes might have on vector ecology and malaria transmission. Methods A 12-month entomological study was conducted in a highly populated district of Douala called Ndogpassi. Adult mosquitoes were collected using two methods: 1 human landing catches (HLC; and 2 Centers for Disease Control and Prevention (CDC light traps; these methods were used twice monthly from January to December 2011. Mosquito genus and species were identified with morphological and molecular diagnostic tools. The sampling efficiency of the CDC light trap and HLC were compared. Anopheles gambiae infection with Plasmodium falciparum was detected using ELISA. Susceptibility to DDT, permethrin, and deltamethrin insecticides were also determined. Results A total of 6923 mosquitoes were collected by HLC (5198 and CDC light traps (1725. There was no equivalence in the sampling efficiency between light traps and human landing catches (P > 0.01. With 51% of the total, Culex was the most common, followed by Anopheles (26.14%, Mansonia (22.7% and Aedes (0.1%. An. gambiae ss (M form comprised ~98% of the total anophelines collected. An. gambiae had a biting rate of 0.25 to 49.25 bites per human per night, and was the only species found to be infected with P. falciparum. A P. falciparum infection rate of 0.5% was calculated (based on enzyme-linked immunosorbent assays using the circumsporozoite surface protein. The entomological inoculation rate was estimated at 31 infective bites per annum. Insecticide susceptibility tests on An. gambiae females revealed a mortality rate of 33%, 76% and 98% for DDT, permethrin and deltamethrin, respectively. The West African kdr allele (L1014F was detected in 38 of

  5. Knowledge and practice of traditional healers in oral health in the Bui Division, Cameroon

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    Naidoo Sudeshni

    2011-01-01

    Full Text Available Abstract Background The majority of Cameroonians depend on traditional medicines for their health care needs and about seven per cent of the average household health budget is spent on traditional medicines irrespective of their incomes. The aim of the present study was to determine the oral care knowledge and practices of Traditional Healers (TH on oral health delivery in the urban and rural areas of Bui Division of Cameroon and the objectives to determine the cost of treatment and reasons why people visit TH. Methods The present study was cross sectional and utilized semi-structured questionnaires to collect data. Results The sample consisted of 21 TH and 52 clients of TH. Sixty two percent of the TH's were above 40 years and 90% male. The mean age was 46 years (range 20-77 years. Twenty four percent of the TH practiced as herbalists and the remainder both divination and herbalism. Sixty seven percent of people in the Bui Division, who patronize TH for their oral health needs, fall within the 20-40 year age group. There is little collaboration between the oral health workers and TH and only 6% of all patients seen by TH are referred to the dentist. Socio-cultural and economic factors affect the oral health care seeking behavior of patients in this area and only 6.5% of patients visit dental clinics. Reasons for not attending dental clinics included high cost, poor accessibility, superstition and fear. TH's are not experienced in the treatment of pulpitis - the majority of patients who presented with toothache had temporary or no relief, but despite this 67% reported being satisfied with their treatment. Sixty nine percent of the patients visited TH because of low cost - the average cost of treatment with TH (approximately $5 is very low, as compared to conventional treatment ($50. Conclusions Traditional healers are willing to co-operate with oral health workers in improving oral health. Since they have a vital role to play in health care

  6. Global volcanic emissions: budgets, plume chemistry and impacts

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    Mather, T. A.

    2012-12-01

    Over the past few decades our understanding of global volcanic degassing budgets, plume chemistry and the impacts of volcanic emissions on our atmosphere and environment has been revolutionized. Global volcanic emissions budgets are needed if we are to make effective use of regional and global atmospheric models in order to understand the consequences of volcanic degassing on global environmental evolution. Traditionally volcanic SO2 budgets have been the best constrained but recent efforts have seen improvements in the quantification of the budgets of other environmentally important chemical species such as CO2, the halogens (including Br and I) and trace metals (including measurements relevant to trace metal atmospheric lifetimes and bioavailability). Recent measurements of reactive trace gas species in volcanic plumes have offered intriguing hints at the chemistry occurring in the hot environment at volcanic vents and during electrical discharges in ash-rich volcanic plumes. These reactive trace species have important consequences for gas plume chemistry and impacts, for example, in terms of the global fixed nitrogen budget, volcanically induced ozone destruction and particle fluxes to the atmosphere. Volcanically initiated atmospheric chemistry was likely to have been particularly important before biological (and latterly anthropogenic) processes started to dominate many geochemical cycles, with important consequences in terms of the evolution of the nitrogen cycle and the role of particles in modulating the Earth's climate. There are still many challenges and open questions to be addressed in this fascinating area of science.

  7. Neogene volcanism in Gutai Mts. (Eastern Carpathains: a review

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    Marinel Kovacs

    2003-04-01

    Full Text Available Two types of volcanism developed in Gutâi Mts. (inner volcanic chain of Eastern Carpathians: a felsic, extensional/“back-arc” type and an intermediate, arc type. The felsic volcanism of explosive origin, consisting of caldera-related rhyolitic ignimbrites and resedimented volcaniclastics, had taken place during Early-Middle Badenian and Early Sarmatian. The intermediate volcanism, consisting of extrusive (effusive and explosive and intrusive activity, had developed during Sarmatian and Pannonian (13.4-7.0 Ma. It is represented by typical calc-alkaline series, from basalts to rhyolites. Lava flows of basaltic andesites and andesites are predominant, often emplaced in subaqueous environment. Extrusive domes, mainly composed of dacites, are associated to the andesitic volcanic structures. The intermediate volcanism, consisting of extrusive (effusive and explosive and intrusive activity, had developed during Sarmatian and Pannonian (13.4-7.0 Ma. It is represented by typical calc-alkaline series, from basalts to rhyolites. Lava flows of basaltic andesites and andesites are predominant, often emplaced in subaqueous environment. Extrusive domes, mainly composed of dacites, are associated to the andesitic volcanic structures. The geochemical study on the volcanic rocks shows the calc-alkaline character of both felsic and intermediate volcanism and typical subduction zones geochemical signatures for the intermediate one. The felsic volcanism shows affinities with subduction-related rocks as well. The main petrogenetic process in Gutâi Mts. was crustal assimilation, strongly constrained by trace element and isotope geochemistry.

  8. Testing the reliability of the Gutenberg-Richter b-value to aid volcanic eruption forecasting

    Science.gov (United States)

    Roberts, Nick; Bell, Andrew; Main, Ian

    2014-05-01

    The distribution of earthquake magnitudes is an important additional attribute of a volcanic earthquake catalogue and analyses of properties of the "frequency-magnitude distribution" (FMD) underpins most studies of volcanic seismicity. The event rate and inter-event intervals are of primary interest as their changes can be a primary indicator of volcanic unrest. The classic model for the earthquake FMD is the Gutenberg-Richter (GR) relation (Gutenberg and Richter, 1954): log(N) = a - bM, where N is the cumulative number of earthquakes of magnitude equal to or greater than M, a is a measure of the total seismicity rate of the region and the b-value represents the relative proportion of large and small events in the catalogue. The b-value for tectonic earthquakes has been well studied with a global average of approximately 1. However, b-values in volcanic settings are often reported to be much higher, sometimes with values as high as 3. Spatial variations in the volcanic b-value have been used to map stress conditions and magma reservoirs, and it has been argued that temporal variations have the potential to forecast eruptive activity. Here we assess different methodologies for analysing properties of the FMD, and re-evaluate what we know about the FMD of volcanic earthquakes. Using synthetic models we evaluate the reliability of methods for calculating the catalogue completeness magnitude where earthquake rates fluctuate rapidly in time to simulate pre-, syn- and post- earthquake swarm activity. We also evaluate to what extent volcanic FMDs are consistent with the GR model, using earthquake data from volcanoes including El Hierro, Canary Islands and Kilauea and Mauna Loa, Hawaii. We suggest that much of the proposed variation in b-value can be attributed to uncertainty in the completeness magnitude, and FMDs not displaying GR properties. In the case where event rate is pulsing or swarming the b-value has a tendency not to stabilise with increasing completeness

  9. Mapping of schistosomiasis and soil-transmitted helminthiasis in the regions of centre, East and West Cameroon.

    Directory of Open Access Journals (Sweden)

    Louis-Albert Tchuem Tchuenté

    Full Text Available BACKGROUND: Schistosomiasis and soil-transmitted helminthiasis (STH are widely distributed in Cameroon. Although mass drug administration (MDA of mebendazole is implemented nationwide, treatment with praziquantel was so far limited to the three northern regions and few health districts in the southern part of Cameroon, based on previous mapping conducted 25 years ago. To update the disease distribution map and determine where treatment with praziquantel should be extended, mapping surveys were conducted in three of the seven southern regions of Cameroon, i.e. Centre, East and West. METHODOLOGY: Parasitological surveys were conducted in April-May 2010 in selected schools in all 63 health districts of the three targeted regions, using appropriate research methodologies, i.e. Kato-Katz and urine filtration. PRINCIPAL FINDINGS: The results showed significant variation of schistosomiasis and STH prevalence between schools, villages, districts and regions. Schistosoma mansoni was the most prevalent schistosome species, with an overall prevalence of 5.53%, followed by S. haematobium (1.72% and S. guineensis (0.14%. The overall prevalence of schistosomiasis across the three regions was 7.31% (95% CI: 6.86-7.77%. The prevalence for Ascaris lumbricoides was 11.48 (95% CI: 10.93-12.04%, Trichuris trichiura 18.22% (95% CI: 17.56-18.90% and hookworms 1.55% (95% CI: 1.35-1.78%, with an overall STH prevalence of 24.10% (95% CI: 23.36-24.85% across the three regions. STH was more prevalent in the East region (46.57%; 95% CI: 44.41-48.75% in comparison to the Centre (25.12; 95% CI: 24.10-26.17% and West (10.49%; 95% CI: 9.57-11.51% regions. CONCLUSIONS/SIGNIFICANCE: In comparison to previous data, the results showed an increase of schistosomiasis transmission in several health districts, whereas there was a significant decline of STH infections. Based on the prevalence data, the continuation of annual or bi-annual MDA for STH is recommended, as well as an

  10. The Effect of Plate Structure on Intraplate Volcanism, Kodiak-Bowie Seamount Chain, Gulf of Alaska

    Science.gov (United States)

    Reece, R. S.; Christeson, G. L.; Gulick, S. S.; Barth, G. A.; Van Avendonk, H. J.

    2012-12-01

    Newly acquired ocean bottom seismometer (OBS) and multi-channel seismic (MCS) data in the vicinity of the Kodiak-Bowie Seamount Chain and Aja Fracture Zone reveal the character and structure of the Pacific Plate, overlying sediment, and seamounts in the Gulf of Alaska. Our data include two marine wide-angle OBS profiles, two coincident MCS profiles, and several nearby MCS profiles, including lines parallel to and crossing the Seamount Chain and Fracture Zone. This new data may help to reveal the character of the Kodiak-Bowie Seamount Chain and associated intraplate volcanism, much of which is concealed by the Surveyor and Baranof sedimentary fan systems. The Kodiak-Bowie Seamount Chain stretches over 1000 km across the Gulf of Alaska, from the Aleutian Trench in the northwest to offshore Queen Charlotte Islands in the southeast. The ages of the seamounts range from 24 Ma at Kodiak Seamount in the northwest to ≥0.7 Ma at Bowie Seamount in the southeast. Although the seamounts are largely age-progressive, some members of the chain are dated significantly out of sequence. Previous studies suggest the possibility that the majority of seamounts in the chain could be products of the Bowie plume. The Gulf-wide Aja Fracture Zone intersects the Kodiak-Bowie Seamount Chain in the central Gulf at the location of the seismic lines. Preliminary tomographic inversions of the seismic data reveal significant changes in crustal thickness across the Aja Fracture Zone, including at least a 3 km step up in the moho from south to north. Additionally, the region north of the Fracture Zone exhibits a 3 km thick low velocity zone in the upper crust, which is double the thickness of the same feature south of the fracture zone. This low velocity zone in the upper crust may be representative of intraplate volcanism associated with the Kodiak-Bowie Chain; several higher velocity perturbations within this zone are coincident with the locations of major seamounts. We will further refine

  11. Io's volcanic influence on the Io plasma torus: HISAKI observation in 2015

    Science.gov (United States)

    Tsuchiya, F.; Yoshioka, K.; Kimura, T.; Murakami, G.; Yoneda, M.; Koga, R.; Kagitani, M.; Sakanoi, T.; Kasaba, Y.; Yamazaki, A.; Yoshikawa, I.

    2015-12-01

    The satellite Io which has many active volcanos supplies volcanic gases to the Jovian magnetosphere with typical rate of 1 ton/sec and has been known be a primary source of plasmas in the magnetosphere. Change in the volcanic activity on Io should cause change of the supply rate and could affect structure of the magnetosphere and dynamics occurs in it. However, responses of the magnetosphere to the volcanic activity is still not fully understood; one of the reasons is lack of continuous and long term observations of Io' volcanic gas extended around Io, plasmas in the Io torus, and activity of the magnetosphere. The extreme ultraviolet (EUV) spectroscope, EXCEED, onboard the HISAKI satellite has capability to measure ion and atomic emission lines in EUV range (55-145nm) and is dedicated to observing solar system planets. The satellite has been successfully launched on Sep. 2013 and 2nd campaign of Io plasma torus and Jovian northern EUV aurora observation has been done from the end of Nov. 2014 to middle of May 2015. On middle of Jan. 2015, HISAKI detected gradual increase in intensity of S+ emission lines and decrease of S3+ ones in the plasma torus. The S+ intensity showed a maximum around the end of Feb. and S++ and S3+ intensities also showed maxima subsequently. Simultaneous ground based observation of the sodium nebula showed increase of the emission intensity from the middle of Jan. to the beginning of Mar. These observations suggest that the volcanic activity began at the middle of Jan. and increase neutral atom and ion densities in the Io torus. The intensities of S+ and S2+ ions returned to the pre-increase level by the middle of May 2015. S3+ had still been in the decay phase at the end of the observation. Change in radial structure of the plasma torus was also found during the volcanic event. The intensity of S+ ion began to increase around the orbit of Io (6 Jovian radii). The brightened region propagated outward and reached at 8.5 Jovian radii from

  12. Assessing forest products usage and local residents' perception of environmental changes in peri-urban and rural mangroves of Cameroon, Central Africa

    Directory of Open Access Journals (Sweden)

    Nfotabong-Atheull Adolphe

    2011-12-01

    Full Text Available Abstract Background Deforestation is one of the most ubiquitous forms of land degradation worldwide. Although remote sensing and aerial photographs can supply valuable information on land/use cover changes, they may not regularly be available for some tropical coasts (e.g., Cameroon estuary where cloud cover is frequent. With respect to mangroves, researchers are now employing local knowledge as an alternative means of understanding forest disturbances. This paper was primarily aimed at assessing the mangrove forest products usage, along with the local people's perceptions on environmental changes, between Littoral (Cameroon estuary and Southern (mouth of the Nyong River and Mpalla village regions of Cameroon. Methods The data from both locations were obtained through conducting household interviews and field observations. Results In the Cameroon estuary (Littoral region, 69.23% of respondents (mostly elders could distinguish two to four mangrove plants, whereas the informants (65.45% in the mouth of the Nyong River and Mpalla village (mostly young people interviewed from the Southern region are familiar with only one or two commonly found mangroves. Also, more respondents from the Cameroon estuary are depending on mangroves for fuelwood (Rhizophora spp. and housing (Rhizophora spp., Avicennia germinans (L. Stearn and Nypa fruticans (Thumb. Wurmb. purposes, in contrast to Nyong River mouth and Mpalla village. Although local people perceived wood extraction as a greater disruptive factor, there are several causes for mangrove depletion in the Cameroon estuary. Among others, over-harvesting, clear-felled corridors, sand extraction and housing were found important. Furthermore, a decline in mangrove fauna composition (in terms of fishery products was recorded in the Littoral as well as Southern regions. However, the causes of such perceived negative changes were not similar in both cases. Conclusions Findings of this study highlight the need to

  13. Hepatotoxicity and effectiveness of a Nevirapine-based antiretroviral therapy in HIV-infected patients with or without viral hepatitis B or C infection in Cameroon

    Directory of Open Access Journals (Sweden)

    Gwet Henri

    2010-03-01

    Full Text Available Abstract Background Coinfection with hepatitis B virus (HBV or hepatitis C virus (HCV in HIV-infected patients receiving a commonly used nevirapine-based antiretroviral therapy is a major concern for African clinicians owing to its high prevalence, the infrequent testing and treatment of viral hepatitis, and the impact of liver disease on the tolerability and effectiveness of anti-HIV treatment. We compared the hepatotoxicity and the immunological, virological and clinical effectiveness of a nevirapine-based antiretroviral therapy between patients infected with HIV only and patients coinfected with hepatitis B or C virus in Cameroon. Methods A retrospective cohort study was conducted among HIV-1-infected patients. Plasma HBV DNA and HCV RNA were tested in positive or indeterminate samples for HBsAg or HCV antibodies, respectively. All patients received nevirapine and lamivudine plus stavudine or zidovudine. Results Of 169 HIV-1-infected patients with a median baseline CD4 count of 135 cells/mm3 (interquartile range [IQR] 67-218, 21% were coinfected with HBV or HCV. In coinfected patients, the median viral load was 2.47 × 107 IU/mL for HBV (IQR 3680-1.59 × 108 and 928 000 IU/mL for HCV (IQR 178 400-2.06 × 106. Multivariate analyses showed that the risk of hepatotoxicity was 2-fold higher in coinfected patients (p p = 0.8, HIV-1 viral load below 400 copies/mL (p = 0.9, death (p = 0.3 and death or new AIDS-defining event (p = 0.1. Nevirapine was replaced by a protease inhibitor in 4 patients owing to hepatotoxicity. Conclusion This study suggests that the nevirapine-based antiretroviral therapy could be used safely as first-line treatment in patients with low CD4 cell count in Africa despite frequent coinfections with HBV or HCV and infrequent testing of these infections. Although testing for HBV and HCV should be systematically performed before initiating antiretroviral therapy, transaminases elevations at baseline or during treatment should be

  14. Volcanic geology of Admiralty Bay, King George Island, Antarctica

    Institute of Scientific and Technical Information of China (English)

    邢光福; 王德滋; 金庆民; 沈渭洲; 陶奎元

    2002-01-01

    At Admiralty Bay of central King George Island, Keller Peninsula, Ullman Spur and Point Hennequin are main Tertiary volcanic terranes. Field investigation and isotopic datings indicate that, there occurred three periods of eruptions ( three volcanic cycles) and accompanying N-toward migration of the volcanic center on Keller Peninsula. After the second period of eruptions, the crater collapsed and a caldera was formed, then later eruptions were limited at the northern end of the peninsula and finally migrated to Ullman Spur. Thus Keller Peninsula is a revived caldera, and its volcanism migrated toward E with time. Point Hennequin volcanism happened more or less simultaneously with the above two areas, but has no clear relation in chemical evolution with them, frequently it belongs to another independent volcanic center.

  15. Supervolcanoes within an ancient volcanic province in Arabia Terra, Mars.

    Science.gov (United States)

    Michalski, Joseph R; Bleacher, Jacob E

    2013-10-03

    Several irregularly shaped craters located within Arabia Terra, Mars, represent a new type of highland volcanic construct and together constitute a previously unrecognized Martian igneous province. Similar to terrestrial supervolcanoes, these low-relief paterae possess a range of geomorphic features related to structural collapse, effusive volcanism and explosive eruptions. Extruded lavas contributed to the formation of enigmatic highland ridged plains in Arabia Terra. Outgassed sulphur and erupted fine-grained pyroclastics from these calderas probably fed the formation of altered, layered sedimentary rocks and fretted terrain found throughout the equatorial region. The discovery of a new type of volcanic construct in the Arabia volcanic province fundamentally changes the picture of ancient volcanism and climate evolution on Mars. Other eroded topographic basins in the ancient Martian highlands that have been dismissed as degraded impact craters should be reconsidered as possible volcanic constructs formed in an early phase of widespread, disseminated magmatism on Mars.

  16. The Yucca Mountain probabilistic volcanic hazard analysis project

    Energy Technology Data Exchange (ETDEWEB)

    Coppersmith, K.J.; Perman, R.C.; Youngs, R.R. [Geomatrix Consultants, Inc., San Francisco, CA (United States)] [and others

    1996-12-01

    The Probabilistic Volcanic Hazard Analysis (PVHA) project, sponsored by the U.S. Department of Energy (DOE), was conducted to assess the probability of a future volcanic event disrupting the potential repository at Yucca Mountain. The PVHA project is one of the first major expert judgment studies that DOE has authorized for technical assessments related to the Yucca Mountain project. The judgments of members of a ten-person expert panel were elicited to ensure that a wide range of approaches were considered for the hazard analysis. The results of the individual elicitations were then combined to develop an integrated assessment of the volcanic hazard that reflects the diversity of alternative scientific interpretations. This assessment, which focused on the volcanic hazard at the site, expressed as the probability of disruption of the potential repository, will provide input to an assessment of volcanic risk, which expresses the probability of radionuclide release due to volcanic disruption.

  17. Assessing volcanic hazard at Yucca Mountain using expert judgment

    Energy Technology Data Exchange (ETDEWEB)

    Coppersmith, K.J.; Perman, R.C. [Geomatrix Consultants, Inc., San Francisco, CA (United States); Nesbit, J. [Department of Energy, Las Vegas, NV (United States)] [and others

    1995-12-01

    A study to assess the probability of a future volcanic event disrupting the potential repository at Yucca Mountain, termed the Probabilistic Volcanic Hazard Analysis (PVHA) project, is being sponsored by the U.S. Department of Energy (DOE). This assessment, which is focused on the volcanic hazard at the site, expressed as the probability of disruption of the potential repository, will eventually provide input to an assessment of volcanic risk, which expresses the probability of radionuclide release due to volcanic disruption. To ensure that a wide range of approaches are considered in the hazard analysis, judgments of members of an expert panel will be elicited. The results of the individual elicitations will be combined to develop an integrated assessment of the volcanic hazard that reflects the diversity of scientific interpretations. This paper outlines the hazard model components and the procedures for eliciting expert judgments.

  18. Supervolcanoes Within an Ancient Volcanic Province in Arabia Terra, Mars

    Science.gov (United States)

    Michalski, Joseph. R.; Bleacher, Jacob E.

    2014-01-01

    Several irregularly shaped craters located within Arabia Terra, Mars represent a new type of highland volcanic construct and together constitute a previously unrecognized martian igneous province. Similar to terrestrial supervolcanoes, these low-relief paterae display a range of geomorphic features related to structural collapse, effusive volcanism, and explosive eruptions. Extruded lavas contributed to the formation of enigmatic highland ridged plains in Arabia Terra. Outgassed sulfur and erupted fine-grained pyroclastics from these calderas likely fed the formation of altered, layered sedimentary rocks and fretted terrain found throughout the equatorial region. Discovery of a new type of volcanic construct in the Arabia volcanic province fundamentally changes the picture of ancient volcanism and climate evolution on Mars. Other eroded topographic basins in the ancient Martian highlands that have been dismissed as degraded impact craters should be reconsidered as possible volcanic constructs formed in an early phase of widespread, disseminated magmatism on Mars.

  19. Volcanic ash plume identification using polarization lidar: Augustine eruption, Alaska

    Science.gov (United States)

    Sassen, Kenneth; Zhu, Jiang; Webley, Peter W.; Dean, K.; Cobb, Patrick

    2007-01-01

    During mid January to early February 2006, a series of explosive eruptions occurred at the Augustine volcanic island off the southern coast of Alaska. By early February a plume of volcanic ash was transported northward into the interior of Alaska. Satellite imagery and Puff volcanic ash transport model predictions confirm that the aerosol plume passed over a polarization lidar (0.694 mm wavelength) site at the Arctic Facility for Atmospheric Remote Sensing at the University of Alaska Fairbanks. For the first time, lidar linear depolarization ratios of 0.10 – 0.15 were measured in a fresh tropospheric volcanic plume, demonstrating that the nonspherical glass and mineral particles typical of volcanic eruptions generate strong laser depolarization. Thus, polarization lidars can identify the volcanic ash plumes that pose a threat to jet air traffic from the ground, aircraft, or potentially from Earth orbit.

  20. High Line

    DEFF Research Database (Denmark)

    Kiib, Hans

    2015-01-01

    At just over 10 meters above street level, the High Line extends three kilometers through three districts of Southwestern Manhattan in New York. It consists of simple steel construction, and previously served as an elevated rail line connection between Penn Station on 34th Street and the many....... The High Line project has been carried out as part of an open conversion strategy. The result is a remarkable urban architectural project, which works as a catalyst for the urban development of Western Manhattan. The greater project includes the restoration and reuse of many old industrial buildings...... in close proximity to the park bridge and new projects being added to fit the context. The outcome is a conglomeration of non-contemporary urban activities along the High Line, where mechanical workshops, small wholesale stores. etc. mix with new exclusive residential buildings, eminent cafés...

  1. High Line

    DEFF Research Database (Denmark)

    Kiib, Hans

    2015-01-01

    in close proximity to the park bridge and new projects being added to fit the context. The outcome is a conglomeration of non-contemporary urban activities along the High Line, where mechanical workshops, small wholesale stores. etc. mix with new exclusive residential buildings, eminent cafés......At just over 10 meters above street level, the High Line extends three kilometers through three districts of Southwestern Manhattan in New York. It consists of simple steel construction, and previously served as an elevated rail line connection between Penn Station on 34th Street and the many...... factories and warehouses on Gansevoort Street. Today the High Line is a beautiful park covered with new tiles, viewing platforms and smaller recreational areas. The park bridge has simple, uniform, urban fittings and features a variety of flowering plants, grasses, shrubs and trees from around the world...

  2. Sexual Abuse in Cameroon: A Four-Year-Old Girl Victim of Rape in Buea Case Study.

    Science.gov (United States)

    Chishugi, John; Franke, Trixy

    2016-01-01

    A young girl was brought to the emergency unit after suffering sexual abuse by an older male. Additional abuses against women and girls include physical beating, forced marriage, female genital mutilation, breast ironing, widow's rites, psychological abuse, and discrimination in education, finance, employment, and legal access. Cameroon has adopted strategies aimed at eliminating violence against women, including ratification of international policies, penal codes, and support of local and international efforts that promote women; however, many of the laws remain in name only and are rarely enforced, given women's lack of financial access to quality lawyers and an unsympathetic male-dominated police force. Underreporting and culturally accepted abuses remain a challenge, too, as the country seeks to understand the extent of abuses and how to effectively fight against them. A complete paradigm shift in cultural attitude toward the female gender is required for abuses to cease.

  3. An Economic Analysis of Boko Haram’s Activities in the Chad-Cameroon-Nigeria Border Area

    Directory of Open Access Journals (Sweden)

    TAMBA Isaac

    2015-02-01

    Full Text Available Terrorism is fast becoming a worldwide phenomenon with about 25% of attacks committed in developing countries. These attacks devastate societies causing huge economic loss with negative growth effects. Recent attacks suspectively conducted by Boko Haram in the north of Nigeria and along its border with Cameroon and Chad are already inflicting damage to local economies with a general drop in savings, investment, trade and a strain on domestic budgets. Poverty and exclusion generate dissidents and reactionary groups activities such as Boko Haram. But, the historical background permits to understand the emergency and the development of some of them. Tackling the Boko Haram threat requires a concerted multinational approach with a key socioeconomic component that incorporates the fact that conflict thrives better in circumstances of poverty and inequality.

  4. A FIELD STUDY OF INDICATORS OF THE PERFORMANCE OF FOUR ABSORPTION CHILLERS IN THE SUDANO-SAHELIAN REGION OF CAMEROON

    Directory of Open Access Journals (Sweden)

    A. N. N. Chedop

    2016-01-01

    Full Text Available This paper presents a field study of indicators of the performance of absorption refrigerating systems in the Sudano-Sahelian region of Cameroon. A modeling of various components of the system is performed in order to choose the technology best adapted for the region. Based on the characteristics from the manufacturers, four absorption chillers were studied; namely: EAW Schüco LB 15 and 30; Rotartica Solar 045 and Sonnenklima Suninverse. The model of Kühn and Ziegler and meteorological data of the city of Maroua ((14.33 °E, 10.58 °N were used to assess the coefficient of the performance (COP of these machines. Results showed that the Sonnenklima Suninverse technology is best suited for the climatic conditions of the Sudano-Sahelian region with COP values between 1.5 and 3.5.

  5. The α-β phase transition in volcanic cristobalite.

    OpenAIRE

    Damby, D. E.; Llewellin, E.W.; Horwell, C. J.; Williamson, B.J.; Najorka, J; Cressey, G.; Carpenter, M.A.

    2014-01-01

    Cristobalite is a common mineral in volcanic ash produced from dome-forming eruptions. Assessment of the respiratory hazard posed by volcanic ash requires understanding the nature of the cristobalite it contains. Volcanic cristobalite contains coupled substitutions of Al3+ and Na+ for Si4+; similar co-substitutions in synthetic cristobalite are known to modify the crystal structure, affecting the stability of the α and β forms and the observed transition between them. Here, for the first time...

  6. Distinguishing volcanic lithology using Self-Organizing Map

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Self-Organizing Map is an unsupervised learning algorithm. It has the ability of self-organization,self-learning and side associative thinking. Based on the principle it can identified the complex volcanic lithology. According to the logging data of the volcanic rock samples, the SOM will be trained, The SOM training results were analyzed in order to choose optimally parameters of the network. Through identifying the logging data of volcanic formations, the result shows that the map can achieve good application effects.

  7. VOLCANIC TSUNAMI GENERATING SOURCE MECHANISMS IN THE EASTERN CARIBBEAN REGION

    OpenAIRE

    2004-01-01

    Earthquakes, volcanic eruptions, volcanic island flank failures and underwater slides have generated numerous destructive tsunamis in the Caribbean region. Convergent, compressional and collisional tectonic activity caused primarily from the eastward movement of the Caribbean Plate in relation to the North American, Atlantic and South American Plates, is responsible for zones of subduction in the region, the formation of island arcs and the evolution of particular volcanic centers on the over...

  8. Plasmodium falciparum-like parasites infecting wild apes in southern Cameroon do not represent a recurrent source of human malaria.

    Science.gov (United States)

    Sundararaman, Sesh A; Liu, Weimin; Keele, Brandon F; Learn, Gerald H; Bittinger, Kyle; Mouacha, Fatima; Ahuka-Mundeke, Steve; Manske, Magnus; Sherrill-Mix, Scott; Li, Yingying; Malenke, Jordan A; Delaporte, Eric; Laurent, Christian; Mpoudi Ngole, Eitel; Kwiatkowski, Dominic P; Shaw, George M; Rayner, Julian C; Peeters, Martine; Sharp, Paul M; Bushman, Frederic D; Hahn, Beatrice H

    2013-04-23

    Wild-living chimpanzees and gorillas harbor a multitude of Plasmodium species, including six of the subgenus Laverania, one of which served as the progenitor of Plasmodium falciparum. Despite the magnitude of this reservoir, it is unknown whether apes represent a source of human infections. Here, we used Plasmodium species-specific PCR, single-genome amplification, and 454 sequencing to screen humans from remote areas of southern Cameroon for ape Laverania infections. Among 1,402 blood samples, we found 1,000 to be Plasmodium mitochondrial DNA (mtDNA) positive, all of which contained human parasites as determined by sequencing and/or restriction enzyme digestion. To exclude low-abundance infections, we subjected 514 of these samples to 454 sequencing, targeting a region of the mtDNA genome that distinguishes ape from human Laverania species. Using algorithms specifically developed to differentiate rare Plasmodium variants from 454-sequencing error, we identified single and mixed-species infections with P. falciparum, Plasmodium malariae, and/or Plasmodium ovale. However, none of the human samples contained ape Laverania parasites, including the gorilla precursor of P. falciparum. To characterize further the diversity of P. falciparum in Cameroon, we used single-genome amplification to amplify 3.4-kb mtDNA fragments from 229 infected humans. Phylogenetic analysis identified 62 new variants, all of which clustered with extant P. falciparum, providing further evidence that P. falciparum emerged following a single gorilla-to-human transmission. Thus, unlike Plasmodium knowlesi-infected macaques in southeast Asia, African apes harboring Laverania parasites do not seem to serve as a recurrent source of human malaria, a finding of import to ongoing control and eradication measures.

  9. Adherence to Antiretroviral Therapy (ART) in Yaoundé-Cameroon: Association with Opportunistic Infections, Depression, ART Regimen and Side Effects.

    Science.gov (United States)

    Fonsah, Julius Y; Njamnshi, Alfred K; Kouanfack, Charles; Qiu, Fang; Njamnshi, Dora M; Tagny, Claude T; Nchindap, Emilienne; Kenmogne, Léopoldine; Mbanya, Dora; Heaton, Robert; Kanmogne, Georgette D

    2017-01-01

    Following global efforts to increase antiretroviral therapy (ART) access in Sub-Saharan Africa, ART coverage among HIV-infected Cameroonians increased from 0% in 2003 to 22% in 2014. However, the success of current HIV treatment programs depends not only on access to ART, but also on retention in care and good treatment adherence. This is necessary to achieve viral suppression, prevent virologic failure, and reduce viral transmission and HIV/AIDS-related deaths. Previous studies in Cameroon showed poor adherence, treatment interruption, and loss to follow-up among HIV+ subjects on ART, but the factors that influence ART adherence are not well known. In the current cross-sectional study, patient/self-reported questionnaires and pharmacy medication refill data were used to quantify ART adherence and determine the factors associated with increased risk of non-adherence among HIV-infected Cameroonians. We demonstrated that drug side-effects, low CD4 cell counts and higher viral loads are associated with increased risk of non-adherence, and compared to females, males were more likely to forego ART because of side effects (pART regimen, age, gender, and education showed that subjects with opportunistic infections had 3.1-times higher odds of having been non-adherent (p40 years) were less likely to be non-adherent (pART during antibiotic treatment (r = 0.53, p = 0.04), and was associated with lower CD4 cell counts (p = 0.04) and longer non-adherent periods (p = 0.04). Change in ART regimen was significantly associated with increased likelihood of non-adherence and increased duration of the non-adherence period. Addressing these underlying risk factors could improve ART adherence, retention in care and treatment outcomes for HIV/AIDS patients in Cameroon.

  10. Pattern of corneal pathologies in children seen at Yaoundé Gynaeco-Obstetric and Paediatric Hospital, Cameroon

    Directory of Open Access Journals (Sweden)

    Bella AL

    2013-10-01

    Full Text Available Assumpta L Bella,1,2 Viola A Dohvoma,1 André O Eballe,3 Oumarou Abdouramani2 1Faculty of Medicine and Biomedical Sciences, University of Yaoundé I, Yaoundé, 2Yaoundé Gynaeco-Obstetric and Paediatric Hospital, Yaoundé, 3Faculty of Medicine and Pharmaceutical Sciences, University of Douala, Douala, Cameroon Purpose: To describe the different corneal pathologies and determine the prevalence of corneal blindness amongst children aged 0–15 years, seen at the ophthalmology unit of a tertiary hospital in Cameroon. Patients and methods: The medical records of all patients who presented to the Ophthalmic Unit between 2002 and 2010 were reviewed, retrospectively. The records of children aged 0–15 years, presenting with corneal pathologies, were further reviewed. Data collected included age, sex, past medical history, initial visual acuity, type of corneal lesion, and visual acuity at last follow-up. Results: Of the 7,922 children seen over the study period, 168 had corneal pathologies: a prevalence of 2.1%. Males were more affected than females (male to female ratio: 1.4:1; P = 0.008. The age range was from 2 weeks to 15 years (mean age: 7.1 years; standard deviation: 4.4 years. The leading etiologies were trauma (48.2%; n = 81 and infection (28.0%; n = 47. Amongst those with available follow-up data, visual impairment and blindness occurred in 50% of the cases (n = 12, with one case being bilateral. Conclusion: Trauma is the most frequent cause of corneal blindness in children. Keywords: keratitis, ocular trauma, childhood blindness

  11. Intestinal parasitic infections in HIV infected and non-infected patients in a low HIV prevalence region, West-Cameroon.

    Science.gov (United States)

    Nkenfou, Céline Nguefeu; Nana, Christelle Tafou; Payne, Vincent Khan

    2013-01-01

    The magnitude of intestinal parasitic infection in acquired immunodeficiency syndrome patients requires careful consideration in the developing world where poor nutrition is associated with poor hygiene and several tropical diseases. However, there have been very few studies addressing this issue in Cameroon. This study was conducted to determine the prevalence of intestinal parasitosis in HIV/AIDS patients in Dschang -Cameroon. Stool and blood specimens from HIV/AIDS patients and control group were screened respectively for intestinal parasites and for HIV antibodies. Intestinal parasites were identified using direct microscopy, formalin-ether concentration and Ziehl Neelsen methods. Out of 396 participants recruited among patients consulting at hospital, 42 (10.6%) were HIV positive, thirty of them treatment naïve. The overall prevalence of intestinal parasites was 14.64%. Out of 42 HIV/AIDS patients, 59.5% (25/42) were infected with intestinal parasites, while only 9.32% (33/354) of the HIV negative patients were infected with intestinal parasites. The parasites detected in our study population included Crystosporidium parvum (2.53%), Entamoeba histolytica (7.52%), Entamoeba coli (4.04%), Giardia lamblia (0.25%), Trichuris trichura (0.25%), Strongyloides stercoralis (0.25%) and Taenia spp. (0.25%). In the HIV infected group, Crystosporidium parvum (19.04%), Entamoeba histolytica (19.04%), Entamoeba coli (21.42%), Giardia lamblia (2.38%), Strongyloides stercoralis (0.25%) and Taenia spp. (0.25%) were found. Crystosporidium parvum was found to be significantly higher in HIV/AIDS patients than in controls (Pintestinal parasitosis. Routine examinations of stool samples for parasites would significantly benefit the HIV patients by contributing in reducing morbidity and improving the efficiency of antiretroviral treatment. Even after the introduction of free anti-retroviral drugs, opportunistic intestinal infections are still a threat. HIV patients should be screened

  12. Factors associated with blood pressure control amongst adults with hypertension in Yaounde, Cameroon: a cross-sectional study

    Science.gov (United States)

    Menanga, Alain; Edie, Sandrine; Boombhi, Jérôme; Musa, Ahmadou Jingi; Mfeukeu, Liliane Kuate; Kingue, Samuel

    2016-01-01

    Background Hypertension is associated with considerable morbidity and mortality. Improvement of its management to reduce adverse cardiovascular outcomes will require an understanding of the patient characteristics and treatment factors associated with uncontrolled blood pressure. Factors that affect blood pressure control have not been sufficiently described in Cameroon. The main goal of our study was to determine the predictors of blood pressure control in patients with hypertension in an urban city in Cameroon. Methods This was descriptive cross-sectional study from five outpatient hypertension consultation units in Hospitals in Yaoundé. Controlled hypertension was defined as blood pressure ≤140/90 mmHg. Logistic regression was used to determine factors associated with blood pressure control. Results Among the 440 patients enrolled in the survey, 280 (63.6%) were females. The mean age was 61 (SD ±11) years. Mean systolic blood pressure (SBP) was 147 mmHg and mean diastolic blood pressure (DBP) was 88 mmHg. Only 36.8% of patients had their mean blood pressure controlled (BP ≤140/90 mmHg). Multivariable logistic regression analysis revealed good adherence to anti-hypertensive medications (OR= 3.99; 95% CI: 2.20–7.23; Plifestyle changes (OR =1.5; 95% CI: 0.53–2.49; P=0.031) to be factors independently associated with controlled hypertension. Conclusions Only one out of three patients has their blood pressure controlled. The results of our study suggest that good adherence to treatment are important factors for tight blood pressure control in primary care. Further identification of patients at risk of non-adherence to treatment and poor blood pressure control can lead to targeted interventions to reduce hypertension related morbidity and mortality in this setting. PMID:27747167

  13. Zircon dating and mineralogy of the Mokong Pan-African magmatic epidote-bearing granite (North Cameroon)

    Science.gov (United States)

    Tchameni, R.; Sun, F.; Dawaï, D.; Danra, G.; Tékoum, L.; Nomo Negue, E.; Vanderhaeghe, O.; Nzolang, C.; Dagwaï, Nguihdama

    2016-09-01

    We present the mineralogy and age of the magmatic epidote-bearing granite composing most of the Mokong pluton, in the Central Africa orogenic belt (North Cameroon). This pluton intrudes Neoproterozoic (~830 to 700 Ma) low- to high-grade schists and gneisses (Poli-Maroua group), and is crosscut or interleaved with bodies of biotite granite of various sizes. The pluton is weakly deformed in its interior, but solid-state deformation increases toward its margins marked by narrow mylonitic bands trending NNE-SSW. The magmatic epidote granitic rocks are classified as quartz monzodiorite, granodiorite, monzogranite, and syenogranite. They are medium- to coarse-grained and composed of K-feldspar + plagioclase + biotite + amphibole + epidote + magnetite + titanite + zircon + apatite. In these granites, the pistacite component [atomic Fe+3/(Fe3+ + Al)] in epidote ranges from 16 to 29 %. High oxygen fugacity (log ƒO2 - 14 to -11) and the preservation of epidote suggest that the magma was oxidized. Al-in hornblende barometry and hornblende-plagioclase thermometry indicate hornblende crystallization between 0.53 and 0.78 GPa at a temperature ranging from 633 to 779 °C. Zircon saturation thermometry gives temperature estimates ranging from 504 to 916 °C, the latter being obtained on samples containing inherited zircons. U/Pb geochronology by LA-ICP-MS on zircon grains characterized by magmatic zoning yields a concordia age of 668 ± 11 Ma (2 σ). The Mokong granite is the only known occurrence magmatic epidote in Cameroon, and is an important milestone for the comparison of the Central Africa orogenic belt with the Brasiliano Fold Belt, where such granites are much more abundant.

  14. The Numba ductile deformation zone (northwest Cameroon): A geometric analysis of folds based on the Fold Profiler method

    Indian Academy of Sciences (India)

    T N Janko; C Njiki Chatu´e; M Kw´ekam; B E Bella Nk´e; A F Yakeu Sandjo; E M Fozing

    2017-03-01

    The Numba ductile deformation zone (NDDZ) is characterised by folds recorded during the three deformation phases that affected the banded amphibole gneiss. Fold-shape analyses using the program Fold Profiler with the aim to show the importance of folding events in the structural analysis of the NDDZ and its contribution to the Pan-African orogeny in central Africa have been made. Classical field method, conic sections method and Ramsay’s fold classification method were applied to (i) have the general orientation of folds, (ii) analyze the fold shapes and (iii) classify the geometry of the folded bands. Fold axes in banded amphibole gneiss plunge moderately (<15◦) towards the NNE or SSW. The morphology of F₁, F₂ and F₃ folds in the study area clearly points to (i) Z-shape folds with SE vergence and (ii) a dextral sense of shear motion. Conic section method reveals two dominant families: F₁ and F₃ folds belong to parabolic shape folds, while F₂ folds belong to parabolic shape and hyperbolic shape folds. Ramsay’s scheme emphasizes class 1C (for F₁, F₂ and F₃ folds) and class 3 (for F₂ folds) as main fold classes. The co-existence of the various fold shapes can be explained by (i) the structuration of the banded gneiss, (ii) the folding mechanisms that associate shear with a non-least compressive or flattening component in a ductile shear zone and (iii) the change in rheological properties of the band during the period of fold formation. These data allow us to conclude that the Numba region underwent ductile dextral shear and can be integrated (i) in a correlation model with the Central Cameroon Shear Zone(CCSZ) and associated syn-kinematic intrusions and (ii) into the tectonic model of Pan-African belt of central Africa in Cameroon.

  15. Adherence to Antiretroviral Therapy (ART) in Yaoundé-Cameroon: Association with Opportunistic Infections, Depression, ART Regimen and Side Effects

    Science.gov (United States)

    Fonsah, Julius Y.; Njamnshi, Alfred K.; Kouanfack, Charles; Qiu, Fang; Njamnshi, Dora M.; Tagny, Claude T.; Nchindap, Emilienne; Kenmogne, Léopoldine; Mbanya, Dora; Heaton, Robert; Kanmogne, Georgette D.

    2017-01-01

    Following global efforts to increase antiretroviral therapy (ART) access in Sub-Saharan Africa, ART coverage among HIV-infected Cameroonians increased from 0% in 2003 to 22% in 2014. However, the success of current HIV treatment programs depends not only on access to ART, but also on retention in care and good treatment adherence. This is necessary to achieve viral suppression, prevent virologic failure, and reduce viral transmission and HIV/AIDS-related deaths. Previous studies in Cameroon showed poor adherence, treatment interruption, and loss to follow-up among HIV+ subjects on ART, but the factors that influence ART adherence are not well known. In the current cross-sectional study, patient/self-reported questionnaires and pharmacy medication refill data were used to quantify ART adherence and determine the factors associated with increased risk of non-adherence among HIV-infected Cameroonians. We demonstrated that drug side-effects, low CD4 cell counts and higher viral loads are associated with increased risk of non-adherence, and compared to females, males were more likely to forego ART because of side effects (p40 years) were less likely to be non-adherent (p<0.01) and had shorter non-adherent periods (p<0.0001). The presence of depression symptoms correlated with non-adherence to ART during antibiotic treatment (r = 0.53, p = 0.04), and was associated with lower CD4 cell counts (p = 0.04) and longer non-adherent periods (p = 0.04). Change in ART regimen was significantly associated with increased likelihood of non-adherence and increased duration of the non-adherence period. Addressing these underlying risk factors could improve ART adherence, retention in care and treatment outcomes for HIV/AIDS patients in Cameroon. PMID:28141867

  16. Distribution and characteristics of volcanic reservoirs in China

    Institute of Scientific and Technical Information of China (English)

    HUANG Yulong; WANG Pujun; CHEN Shuming

    2009-01-01

    About forty productive oil/gas fields hosted in volcanic reservoirs have been found since 1957 in fourteen basins of China. They can be simply subdivided into two groups, the east and the west. Reservoir volcanic rocks of the east group are predominantly composed of Late Jurassic to Early Cretaceous rhyolite and Tertiary basalt, preferred being considered as rift type volcanics developed in the circum-Pacific tectonic regime. Those of the west are Permo-Carboniferous intermediate/basic volcanic rocks, being island-arc type ones developed in paleo-Asian Ocean tectonic regime.

  17. Melting Behavior of Volcanic Ash relevant to Aviation Ash Hazard

    Science.gov (United States)

    Song, W.; Hess, K.; Lavallee, Y.; Cimarelli, C.; Dingwell, D. B.

    2013-12-01

    Volcanic ash is one of the major hazards caused by volcanic eruptions. In particular, the threat to aviation from airborne volcanic ash has been widely recognized and documented. In the past 12 years, more than 60 modern jet airplanes, mostly jumbo jets, have been damaged by drifting clouds of volcanic ash that have contaminated air routes and airport facilities. Seven of these encounters are known to have caused in-flight loss of engine power to jumbo jets carrying a total of more than 2000 passengers. The primary cause of engine thrust loss is that the glass in volcanic ash particles is generated at temperatures far lower than the temperatures in the combustion chamber of a jet engine ( i.e. > 1600 oC) and when the molten volcanic ash particles leave this hottest section of the engine, the resolidified molten volcanic ash particles will be accumulated on the turbine nozzle guide vanes, which reduced the effective flow of air through the engine ultimately causing failure. Thus, it is essential to investigate the melting process and subsequent deposition behavior of volcanic ash under gas turbine conditions. Although few research studies that investigated the deposition behavior of volcanic ash at the high temperature are to be found in public domain, to the best our knowledge, no work addresses the formation of molten volcanic ash. In this work, volcanic ash produced by Santiaguito volcano in Guatemala in November 8, 2012 was selected for study because of their recent activity and potential hazard to aircraft safety. We used the method of accessing the behavior of deposit-forming impurities in high temperature boiler plants on the basis of observations of the change in shape and size of a cylindrical coal ash to study the sintering and fusion phenomena as well as determine the volcanic ash melting behavior by using characteristic temperatures by means of hot stage microscope (HSM), different thermal analysis (DTA) and Thermal Gravimetric Analysis (TGA) to

  18. Exceptional Volumes of Rejuvenated Volcanism in Samoa

    Science.gov (United States)

    Konter, J. G.; Jackson, M.; Storm, L.

    2010-12-01

    The internal structure of within-plate volcanoes is typically compared to the stages of volcanic evolution in Hawaii. In Samoa, these stages show some differences with the Hawaiian model, in terms of the duration, volume and geochemical composition of the stages. Particularly, the rejuvenated stage of volcanism in Samoa is significantly more voluminous, with increasing geographic coverage with age, completely repaving the island of Savai’i. This unusual outpouring of rejuvenated lavas has previously been proposed to be related to the tectonic setting, near the northern terminus of the Tonga Trench. Therefore, Samoan volcanism might be caused by lithospheric fracturing, a mantle plume, or potentially a combination of the two. We collected new samples from a deeply eroded canyon on Savai’i to determine a time evolution of the transition from shield to eventual rejuvenated lavas. The canyon exposes several hundred meters of lavas, and we collected samples about 200m vertically down into the canyon. These samples are dominantly olivine basalts, and their Pb isotope compositions fall within the compositional field of young rejuvenated lavas on Savai’i and Upolu. This canyon section, therefore, represents a minimum thickness for the rejuvenated lavas of 200m. Assuming eruption of rejuvenated lavas only occurred subaerially, with a universal thickness of 200m, the new data suggest more than one percent of the volume of Savai’i consists of rejuvenated lavas. This is an order of magnitude greater than the largest relative volumes in Hawaii (Kauai), and implies a different cause for rejuvenated volcanism in Samoa. Another feature that suggests different processes may be important is the transition between the shield and rejuvenated stage. Although Samoan volcanoes do not seem to erupt exactly the same rock types as characteristic Hawaiian post-shield stage lavas, there is a definite shift to more evolved compositions (including trachytes) during the later stages of

  19. Volcanic hazard assessment at Deception Island

    Science.gov (United States)

    Bartolini, S.; Sobradelo, R.; Geyer, A.; Martí, J.

    2012-04-01

    Deception Island is the most active volcano of the South Shetland Islands (Antarctica) with more than twenty eruptions recognised over the past two centuries. The island was formed on the expansion axis of the Central Bransfield Strait and its evolution consists of constructive and destructive phases. A first a shield phase was followed by the construction of a central edifice and formation of the caldera with a final monogenetic volcanism along the caldera rim. The post-caldera magma composition varies from andesitic-basaltic to dacitic. The activity is characterised by monogenetic eruptions of low volume and short duration. The eruptions show a variable degree of explosivity, strombolian or phreatomagmatic, with a VEI 2 to 4, which have generated a wide variety of pyroclastic deposits and lavas. It is remarkable how many phases of phreatic explosive eruptions are associated to the emission of large ballistic blocks. Tephra record preserved in the glacier ice of Livingston Island or in marine sediments show the explosive power of the phreatomagmatic phases and the wide dispersal of its finest products in a great variety of directions of the prevailing winds. Also it is important to highlight the presence of different lahar deposits associated with some of these eruptions. In this contribution we present the guidelines to conduct a short-term and long-term volcanic hazard assessment at Deception Island. We apply probabilistic methods to estimate the susceptibility, statistical techniques to determine the eruption recurrence and eruptive scenario, and reproduce the effects of historical eruptions too. Volcanic hazard maps and scenarios are obtained using a Voris-based model tool (Felpeto et al., 2007) in a free Geographical Information System (GIS), a Quantum GIS.

  20. Structural significance of the south Tyrrhenian volcanism

    Science.gov (United States)

    Gaudiosi, G.; Musacchio, G.; Ventura, G.; de Astis, G.

    2003-04-01

    The southern part of the Tyrrhenian Sea represents a transition from ocenic- (the Tyrrhenian Sea) to continental-domain (the Calabrian Arc) and is affected by active calkalkaline to potassic volcanism (the Eolian Islands). Active extensional tectonics, coupled with the general upwelling of northern Sicily and Calabria continental crust, coexists with active subduction of the Ionian Plate beneath the Calabrian Arc. This has been interpreted as the result of the detachment of the slab beneath the Calbrian Arc. Present-day tectonics is characterized by NE-SW normal faults and NNW- SSE dextral oblique-slip faults. The normal faults form the major peri- Tyrrhenian basins. Refraction and high resolution onshore-offshore wide-angle-reflection profiles, as well as potential field modeling, provide a 3D image of the Moho. Short wave-length undulations characterize the Moho beneath the Aeolian Arch. The major upraise is about 6 km, beneath the Aeolian active volcanic area, and affects all the crustal boundaries. Another sharp crustal thinning is observed beneath the gulf of Patti at the south-eastern edge of the Tyrrhenian basin. We suggest that the graben-like structure, occurring along the Salina-Lipari-Vulcano islands and oriented at high angles to the trench, is lithospheric and can be followed down to Moho depths. NNW-SSE dextral oblique-slip faults, like the Tindari Letojanni fault system, control the Salina-Lipari-Vulcano portion of the Aeolian volcanism and connect the oceanic crust of the Marsili Basin to the Malta Escarpment, through the Etna volcano. Across this lineament seismicity changes from mostly shallow to the west, to deep intra- slab to the east.

  1. Volcanic hazards on the Island of Hawaii

    Science.gov (United States)

    Mullineaux, Donal Ray; Peterson, Donald W.

    1974-01-01

    Volcanic hazards on the Island of Hawaii have been determined to be chiefly products of eruptions: lava flows, falling fragments, gases, and particle-and-gas clouds. Falling fragments and particle-and-gas clouds can be substantial hazards to life, but they are relatively rare. Lava flows are the chief hazard to property; they are frequent and cover broad areas. Rupture, subsidence, earthquakes, and sea waves (tsunamis) caused by eruptions are minor hazards; those same events caused by large-scale crustal movements, however, are major hazards to both life and property. Volcanic hazards are greatest on Mauna Loa and Kilauea, and the risk is highest along the rift zones of those volcanoes. The hazards are progressively less severe on Hualalai, Mauna Kea, and Kohala volcanoes. Some risk from earthquakes extends across the entire island, and the risk from tsunamis is high all along the coast. The island has been divided into geographic zones of different relative risk for each volcanic hazard, and for all those hazards combined. Each zone is assigned a relative risk for that area as a whole; the degree of risk varies within the zones, however, and in some of them the risk decreases gradationally across the entire zone. Moreover, the risk in one zone may be locally as great or greater than that at some points in the zone of next higher overall risk. Nevertheless, the zones can be highly useful for land-use planning. Planning decisions to which the report is particularly applicable include the selection of kinds of structures and kinds of land use that are appropriate for the severity and types of hazards present. For example, construction of buildings that can resist a lava flow is generally not feasible, but it is both feasible and desirable to build structures that can resist falling rock fragments, earthquakes, and tsunamis in areas where risk from those hazards is relatively high. The report can also be used to select sites where overall risk is relatively low, to

  2. Payenia volcanic province, southern Mendoza, Argentina

    DEFF Research Database (Denmark)

    Søager, Nina; Holm, Paul Martin; Llambias, Eduardo Jorge

    2013-01-01

    The Pleistocene to Holocene Payenia volcanic province is a backarc region of 60,000 km2 in Mendoza, Argentina, which is dominated by transitional to alkaline basalts and trachybasalts. We present major and trace element compositions of 139 rocks from this area of which the majority are basaltic...... basalts, trace element variations suggest a significant contribution from lower crustal melts, possibly up to 70% in the most extreme cases. The contaminating lower crustal rocks must have been depleted mafic rocks with a plagioclase component. The extensive melting of lower crust is probably related...

  3. Volcanism/tectonics working group summary

    Energy Technology Data Exchange (ETDEWEB)

    Kovach, L.A. [Nuclear Regulatory Commission, Washington, DC (United States); Young, S.R. [Center for Nuclear Waste Regulatory Analyses, San Antonio, TX (United States)

    1995-09-01

    This article is a summary of the proceedings of a group discussion which took place at the Workshop on the Role of Natural Analogs in Geologic Disposal of High-Level Nuclear Waste in San Antonio, Texas on July 22-25, 1991. The working group concentrated on the subject of the impacts of earthquakes, fault rupture, and volcanic eruption on the underground repository disposal of high-level radioactive wastes. The tectonics and seismic history of the Yucca Mountain site in Nevada is discussed and geologic analogs to that site are described.

  4. Ice nucleating properties of volcanic ash particles from the Eyjafjallajökull volcanic eruption

    Science.gov (United States)

    Kulkarni, G.; Zelenyuk, A.; Beranek, J.

    2011-12-01

    The volcanic ash from the volcanic emissions can significantly contribute to the natural source of aerosols in the atmosphere. In the vicinity and downwind of eruption site, the transported ash might have a stronger impact on the aviation industry, regional air quality, and climate. Despite the environmental significance of ash, our understanding of ash particles reacting with other volcanic plume constituents is rudimentary. In particular, the complex interactions between the water vapor and ash particles under different meteorological conditions that lead to cloud hydrometeors are poorly understood. To improve our understanding, we focus on investigating the ice formation properties of ash particles collected from the recent volcanic eruption. It was observed that the ash particles are less efficient ice nuclei compared to the natural dust particles in the deposition nucleation regime, but have similar efficiencies in the condensation freezing mode. The ice nucleated ash particles are separated from the interstitial particles, and further evaporated to understand the elemental composition, size, shape and morphology of the ice residue using the single particle mass spectrometer. The elemental composition reveals that majority of the elements are also present in the natural dust particles, but subtle differences are observed. This suggests that particle properties play an important role in the ice nucleation process.

  5. Experiments on the formation of volcanic cones (In connection with East Indian volcanic islands)

    NARCIS (Netherlands)

    Kuenen, Ph.H.

    1933-01-01

    Several investigators have tackled the problem of the main causes that produce the slopes of volcanic cones, especially with a view to explaining the characteristic concave profiles of strato-volcanoes *). A satisfactory result has not been arrived at, however. This became evident to the present aut

  6. How often are ethics approval and informed consent reported in publications on health research in Cameroon? A five-year review.

    Science.gov (United States)

    Munung, Nchangwi Syntia; Che, Chi Primus; Ouwe-Missi-Oukem-Boyer, Odile; Tangwa, Godfrey B

    2011-09-01

    We assessed the extent of research ethics approval and informed consent reporting in publications emanating from Cameroon and indexed in PubMed from 2005-2009. In our review of 219 full-length articles, we found that 57.53% reported ethics approval, 70.78% informed consent, and 50.68% both ethics approval and informed consent. Reporting these procedures was more common in randomized clinical trials than in other study designs. Also, 59.52% of the articles on vulnerable populations documented ethics approval and 76.19% documented informed consent. This study also identified some structures for ethics review and recommends some next steps for research on the quality of ethics review in Cameroon.

  7. The Lake Chad Basin, an Isolated and Persistent Reservoir of Vibrio cholerae O1: A Genomic Insight into the Outbreak in Cameroon, 2010

    DEFF Research Database (Denmark)

    Kaas, Rolf Sommer; Ngandjio, Antoinette; Nzouankeu, Ariane

    2016-01-01

    The prevalence of reported cholera was relatively low around the Lake Chad basin until 1991. Since then, cholera outbreaks have been reported every couple of years. The objective of this study was to investigate the 2010/2011 Vibrio cholerae outbreak in Cameroon to gain insight into the genomic...... make-up of the V. cholerae strains responsible for the outbreak. Twenty-four strains were isolated and whole genome sequenced. Known virulence genes, resistance genes and integrating conjugative element (ICE) elements were identified and annotated. A global phylogeny (378 genomes) was inferred using...... a single nucleotide polymorphism (SNP) analysis. The Cameroon outbreak was found to be clonal and clustered distant from the other African strains. In addition, a subset of the strains contained a deletion that was found in the ICE element causing less resistance. These results suggest that V. cholerae...

  8. The Lake Chad Basin, an Isolated and Persistent Reservoir of Vibrio cholerae O1: A Genomic Insight into the Outbreak in Cameroon, 2010

    Science.gov (United States)

    Kaas, Rolf S.; Ngandjio, Antoinette; Nzouankeu, Ariane; Siriphap, Achiraya; Fonkoua, Marie-Christine; Aarestrup, Frank M.; Hendriksen, Rene S.

    2016-01-01

    The prevalence of reported cholera was relatively low around the Lake Chad basin until 1991. Since then, cholera outbreaks have been reported every couple of years. The objective of this study was to investigate the 2010/2011 Vibrio cholerae outbreak in Cameroon to gain insight into the genomic make-up of the V. cholerae strains responsible for the outbreak. Twenty-four strains were isolated and whole genome sequenced. Known virulence genes, resistance genes and integrating conjugative element (ICE) elements were identified and annotated. A global phylogeny (378 genomes) was inferred using a single nucleotide polymorphism (SNP) analysis. The Cameroon outbreak was found to be clonal and clustered distant from the other African strains. In addition, a subset of the strains contained a deletion that was found in the ICE element causing less resistance. These results suggest that V. cholerae is endemic in the Lake Chad basin and different from other African strains. PMID:27191718

  9. The exploitation of "Exploitation" in the tenofovir prep trial in Cameroon: Lessons learned from media coverage of an HIV prevention trial.

    Science.gov (United States)

    Mack, Natasha; Robinson, Elizabeth T; MacQueen, Kathleen M; Moffett, Jill; Johnson, Laura M

    2010-06-01

    media coverage influences how clinical trials are perceived internationally and in communities where trials occur, affecting recruitment, retention, and political support for research. We conducted a discourse analysis of news coverage from 2004-2005 of a trial in Cameroon on oral PrEP for HIV prevention, to identify messages, communication techniques, and sources of messages that were amplified via media. We identified two parallel discourses: one on ethical concerns about the Cameroon trial, and a second, more general "science exploitation" discourse concerned with the potential for trials with vulnerable participant populations to be conducted unethically, benefiting only wealthy populations. Researchers should overtly address exploitation as an integral, ongoing component of research, particularly where historical or cultural conditions set the stage for controversy to emerge.

  10. Oxygen Isotope Character of the Lake Owyhee Volcanic Field, Oregon

    Science.gov (United States)

    Blum, T.; Strickland, A.; Valley, J. W.

    2012-12-01

    Oxygen isotope analyses of zircons from lavas and tuffs from the Lake Owyhee Volcanic Field (LOVF) of east central Oregon unequivocally demonstrate the presence of mid-Miocene low-δ18O magmas (δ18Ozrc<4.7 ‰). Despite the growing data set of low-δ18O melts within, and proximal to, the Snake River Plain (SRP) Large Igneous Province, debate persists regarding both the mechanisms for low-δ18O magma petrogenesis, and their relative influence in the SRP. The LOVF is associated with widespread silicic volcanism roughly concurrent with the eruption of the Steens-Columbia River Basalt Group between ~17-15Ma. Silicic activity in the LOVF is limited to 16-15Ma, when an estimated 1100km3 of weakly peralkaline to metaluminous rhyolitic lavas and ignimbrites erupted from a series of fissures and calderas. Geographically, the LOVF overlaps the Oregon-Idaho Graben (OIG), and straddles the 87Sr/86Sr= 0.704 line which, together with the 0.706 line to the east, delineate the regional transition from the North American Precambrian continental crust to the east to younger Phanerozoic accreted terranes to the west. Here we report high accuracy ion microprobe analyses of δ18O in zircons using a 10-15μm spot, with average spot-to-spot precision ±0.28‰ (2SD), to investigate intra-grain and intra-unit δ18Ozrc trends for LOVF rhyolites. Due to its high closure temperature, chemical and physical resistance, and slow oxygen diffusion rates, zircon offers a robust record of magmatic oxygen isotope ratios during crystallization and provides constraints on the petrogenesis of Snake River Plain (SRP) low-δ18O melts. Individual zircons from LOVF rhyolites show no evidence of core-rim δ18O zoning, and populations exhibit ≤0.42‰ (2SD) intra-unit variability. Unit averages range from 2.2 to 4.3‰, with the lowest values in caldera-forming ignimbrites, but all units show evidence of crystallization from low-δ18O melts. Quartz and feldspar analyses by laser fluorination (precision

  11. Mineralogy and geochemistry of laterites developed on chlorite schists in Tchollire region, North Cameroon

    Science.gov (United States)

    Banakeng, L. A.; Zame, P. Zo'o.; Tchameni, R.; Mamdem, L.; Bitom, D.

    2016-07-01

    Laterites developed from the weathering of chlorite schists have been studied in Tchollire region, North Cameroon. They include two profiles: a 5.5 m depth profile in Doudja site and a 12.3 m profile in Fimbe site. The chlorite schists have a lepidoblastic to lepidogranoblastic texture and are mainly composed of chlorite, muscovite, biotite, feldspars and quartz but that of Fimbe is marked by the presence of amphibole. It is felsic with a high SiO2 content (67%) and low Fe2O3 (5.8%) and MgO (2.4%) contents in Doudja site but has a lower content of SiO2 (46%) in the Fimbe site where it is mafic with higher contents in Fe2O3 (12.4%) and MgO (6.3%). The chlorite schists of Doudja show high contents in Zr, Sr, Ta, with moderate contents in Cr, V, U and Zn. That of Fimbe is particularly rich in Cr, V, Ni, Sr and Zn with a moderate Zr content. All chlorite schists have high barium contents (270-393 ppm) with LREE-enrichment. The soils are yellowish and, from bottom to top, are composed of a coarse saprolite, fine saprolite, loose clayey horizon and an organo mineral horizon. The main minerals are chlorite, muscovite, biotite, feldspars, quartz, smectites, vermiculite, kaolinite, hematite and goethite. In Doudja, SiO2 mainly decreases from the bottom to the top of the profile while, Al2O3 and Fe2O3 generally increase; in Fimbe, SiO2 and Al2O3 increase up the profile but Fe2O3 decreases; the general high Fe and corresponding decrease in Mg contents in the soils show that the smectite formed is nontronite. Chromium, V, Cu, Ba and Sr show high contents in the two studied profiles but Zr, U and Ta is higher in Doudja than in Fimbe. Copper generally has high contents in the loose clayey and organo mineral horizons. Nickel is higher in the Fimbe profile and probably issued from the Ni-rich mafic protolith. SiO2 has positive correlations with K2O, Zr, Li and Rb. Correlations of SiO2 with CaO, TiO2 and Cr are negative. Al2O3 and Fe2O3 have a positive correlation with Pb. Doudja

  12. DENSITY AND NATURAL REGENERATION POTENTIAL OF SELECTED NON-TIMBER FOREST PRODUCTS SPECIES IN THE SEMI-DECIDUOUS RAINFOREST OF SOUTHEASTERN CAMEROON

    OpenAIRE

    FONGNZOSSIE FEDOUNG, Evariste; NGANSOP TOUNKAM, Marlène; Zapfack, Louis; KEMEUZE, Victor Aimé; SONWA, Denis Jean; NGUENANG, Guy Merlin; NKONGMENECK Bernard-Aloys

    2014-01-01

    This study was conducted to determine the population structure and the status of natural regeneration for eight edible and/or commercial wild fruit tree species (Afrostyrax lepidophyllus, Baillonella toxisperma, Irvingia gabonensis, Panda oleosa, Pentaclethra macrophylla, Ricinodendron heudelotii, Scorodophloeus zenkeri and Tetrapleura tetraptera) in semi-deciduous rainforest of southeastern Cameroon. We established 16 transects with 5 km in length and 20 m in width each. Along each transect,...

  13. Characterization of Enteroviruses from non-human primates in cameroon revealed virus types widespread in humans along with candidate new types and species.

    Directory of Open Access Journals (Sweden)

    Serge Alain Sadeuh-Mba

    Full Text Available Enteroviruses (EVs infecting African Non-Human Primates (NHP are still poorly documented. This study was designed to characterize the genetic diversity of EVs among captive and wild NHP in Cameroon and to compare this diversity with that found in humans. Stool specimens were collected in April 2008 in NHP housed in sanctuaries in Yaounde and neighborhoods. Moreover, stool specimens collected from wild NHP from June 2006 to October 2008 in the southern rain forest of Cameroon were considered. RNAs purified directly from stool samples were screened for EVs using a sensitive RT-nested PCR targeting the VP1 capsid coding gene whose nucleotide sequence was used for molecular typing. Captive chimpanzees (Pan troglodytes and gorillas (Gorilla gorilla were primarily infected by EV types already reported in humans in Cameroon and elsewhere: Coxsackievirus A13 and A24, Echovirus 15 and 29, and EV-B82. Moreover EV-A119, a novel virus type recently described in humans in central and west Africa, was also found in a captive Chimpanzee. EV-A76, which is a widespread virus in humans, was identified in wild chimpanzees, thus suggesting its adaptation and parallel circulation in human and NHP populations in Cameroon. Interestingly, some EVs harbored by wild NHP were genetically distinct from all existing types and were thus assigned as new types. One chimpanzee-derived virus was tentatively assigned as EV-J121 in the EV-J species. In addition, two EVs from wild monkeys provisionally registered as EV-122 and EV-123 were found to belong to a candidate new species. Overall, this study indicates that the genetic diversity of EVs among NHP is more important than previously known and could be the source of future new emerging human viral diseases.

  14. African women in political leadership : a comparative study of cameroon (1192-2011) and SOuth Africa (1994-2011) / G.M Ashu

    OpenAIRE

    Ashu, G M

    2012-01-01

    The main aim of the study was to compare the state of women's political representation in the leadership structures of South Africa and Cameroon after almost two decades of multi-party politics in these two African states. The objectives were: to examine the structures and mechanisms that have been put in place in both countries to promote and advance gender equality and women's empowerment; to find out the obstacles which inhibit women's political representation or their ad...

  15. Factors Associated with Fatal Outcomes Following Cholera-Like Syndrome in Far North Region of Cameroon: A Community-Based Survey.

    Science.gov (United States)

    Djouma, Fabrice N; Ateudjieu, Jerome; Ram, Malathi; Debes, Amanda K; Sack, David A

    2016-12-07

    This study demonstrates that most cholera deaths in this region of Cameroon occur out of hospital. This is a region which is prone to cholera, and interventions are needed to improve access to emergency medical care, especially during cholera outbreaks. Cameroon has experienced 14 cholera epidemics during the last 20 years, and these have had high case fatality rates. This study attempted to assess the effect of delays in seeking care and the locations of care as possible risk factors for cholera mortality. The study used data from a community-based survey regarding the circumstances of 97 fatal cases and 197 control (nonfatal) cases following a cholera-like syndrome in villages with cholera-like diseases during cholera outbreaks in Cameroon during 2009-2011. Deaths occurred in one of four environments: the community, in a temporary community treatment center (TCTC), in transit to a treatment center, or in a hospital (39%, 32%, 5%, and 24%, respectively). Using a case-control analysis, factors associated with deaths included the nonuse of a cholera treatment center, receiving health care in a TCTC instead of a hospital, and greater than 4 hours delay between the onset of symptoms and the decision to go to a treatment center (odds ratios of 17.1 [confidence interval (CI): 7.0-41.8], 2.5 [CI: 1.2-5.0], and 2.2 [CI: 1.0-4.6], respectively). During cholera epidemics, a higher proportion of deaths are still occurring in communities. The nonuse and delays in deciding to go a treatment center, and treatment at TCTC rather than a hospital were risk factors for death among patients with cholera-like syndrome in Cameroon. Informing people on community management of cholera-like syndrome and improving care in all health facilities are needed to reduce deaths during cholera epidemics.

  16. VOLCANIC TSUNAMI GENERATING SOURCE MECHANISMS IN THE EASTERN CARIBBEAN REGION

    Directory of Open Access Journals (Sweden)

    George Pararas-Carayannis

    2004-01-01

    Full Text Available Earthquakes, volcanic eruptions, volcanic island flank failures and underwater slides have generated numerous destructive tsunamis in the Caribbean region. Convergent, compressional and collisional tectonic activity caused primarily from the eastward movement of the Caribbean Plate in relation to the North American, Atlantic and South American Plates, is responsible for zones of subduction in the region, the formation of island arcs and the evolution of particular volcanic centers on the overlying plate. The inter-plate tectonic interaction and deformation along these marginal boundaries result in moderate seismic and volcanic events that can generate tsunamis by a number of different mechanisms. The active geo-dynamic processes have created the Lesser Antilles, an arc of small islands with volcanoes characterized by both effusive and explosive activity. Eruption mechanisms of these Caribbean volcanoes are complex and often anomalous. Collapses of lava domes often precede major eruptions, which may vary in intensity from Strombolian to Plinian. Locally catastrophic, short-period tsunami-like waves can be generated directly by lateral, direct or channelized volcanic blast episodes, or in combination with collateral air pressure perturbations, nuéss ardentes, pyroclastic flows, lahars, or cascading debris avalanches. Submarine volcanic caldera collapses can also generate locally destructive tsunami waves. Volcanoes in the Eastern Caribbean Region have unstable flanks. Destructive local tsunamis may be generated from aerial and submarine volcanic edifice mass edifice flank failures, which may be triggered by volcanic episodes, lava dome collapses, or simply by gravitational instabilities. The present report evaluates volcanic mechanisms, resulting flank failure processes and their potential for tsunami generation. More specifically, the report evaluates recent volcanic eruption mechanisms of the Soufriere Hills volcano on Montserrat, of Mt. Pel

  17. Actinobacterial Diversity in Volcanic Caves and Associated Geomicrobiological Interactions.

    Science.gov (United States)

    Riquelme, Cristina; Marshall Hathaway, Jennifer J; Enes Dapkevicius, Maria de L N; Miller, Ana Z; Kooser, Ara; Northup, Diana E; Jurado, Valme; Fernandez, Octavio; Saiz-Jimenez, Cesareo; Cheeptham, Naowarat

    2015-01-01

    Volcanic caves are filled with colorful microbial mats on the walls and ceilings. These volcanic caves are found worldwide, and studies are finding vast bacteria diversity within these caves. One group of bacteria that can be abundant in volcanic caves, as well as other caves, is Actinobacteria. As Actinobacteria are valued for their ability to produce a variety of secondary metabolites, rare and novel Actinobacteria are being sought in underexplored environments. The abundance of novel Actinobacteria in volcanic caves makes this environment an excellent location to study these bacteria. Scanning electron microscopy (SEM) from several volcanic caves worldwide revealed diversity in the morphologies present. Spores, coccoid, and filamentous cells, many with hair-like or knobby extensions, were some of the microbial structures observed within the microbial mat samples. In addition, the SEM study pointed out that these features figure prominently in both constructive and destructive mineral processes. To further investigate this diversity, we conducted both Sanger sequencing and 454 pyrosequencing of the Actinobacteria in volcanic caves from four locations, two islands in the Azores, Portugal, and Hawai'i and New Mexico, USA. This comparison represents one of the largest sequencing efforts of Actinobacteria in volcanic caves to date. The diversity was shown to be dominated by Actinomycetales, but also included several newly described orders, such as Euzebyales, and Gaiellales. Sixty-two percent of the clones from the four locations shared less than 97% similarity to known sequences, and nearly 71% of the clones were singletons, supporting the commonly held belief that volcanic caves are an untapped resource for novel and rare Actinobacteria. The amplicon libraries depicted a wider view of the microbial diversity in Azorean volcanic caves revealing three additional orders, Rubrobacterales, Solirubrobacterales, and Coriobacteriales. Studies of microbial ecology in

  18. Nano-volcanic Eruption of Silver

    Science.gov (United States)

    Lin, Shih-Kang; Nagao, Shijo; Yokoi, Emi; Oh, Chulmin; Zhang, Hao; Liu, Yu-Chen; Lin, Shih-Guei; Suganuma, Katsuaki

    2016-10-01

    Silver (Ag) is one of the seven metals of antiquity and an important engineering material in the electronic, medical, and chemical industries because of its unique noble and catalytic properties. Ag thin films are extensively used in modern electronics primarily because of their oxidation-resistance. Here we report a novel phenomenon of Ag nano-volcanic eruption that is caused by interactions between Ag and oxygen (O). It involves grain boundary liquation, the ejection of transient Ag-O fluids through grain boundaries, and the decomposition of Ag-O fluids into O2 gas and suspended Ag and Ag2O clusters. Subsequent coating with re-deposited Ag-O and the de-alloying of O yield a conformal amorphous Ag coating. Patterned Ag hillock arrays and direct Ag-to-Ag bonding can be formed by the homogenous crystallization of amorphous coatings. The Ag “nano-volcanic eruption” mechanism is elaborated, shedding light on a new mechanism of hillock formation and new applications of amorphous Ag coatings.

  19. Nano-volcanic Eruption of Silver

    Science.gov (United States)

    Lin, Shih-kang; Nagao, Shijo; Yokoi, Emi; Oh, Chulmin; Zhang, Hao; Liu, Yu-chen; Lin, Shih-guei; Suganuma, Katsuaki

    2016-01-01

    Silver (Ag) is one of the seven metals of antiquity and an important engineering material in the electronic, medical, and chemical industries because of its unique noble and catalytic properties. Ag thin films are extensively used in modern electronics primarily because of their oxidation-resistance. Here we report a novel phenomenon of Ag nano-volcanic eruption that is caused by interactions between Ag and oxygen (O). It involves grain boundary liquation, the ejection of transient Ag-O fluids through grain boundaries, and the decomposition of Ag-O fluids into O2 gas and suspended Ag and Ag2O clusters. Subsequent coating with re-deposited Ag-O and the de-alloying of O yield a conformal amorphous Ag coating. Patterned Ag hillock arrays and direct Ag-to-Ag bonding can be formed by the homogenous crystallization of amorphous coatings. The Ag “nano-volcanic eruption” mechanism is elaborated, shedding light on a new mechanism of hillock formation and new applications of amorphous Ag coatings. PMID:27703220

  20. Supercomputer modeling of volcanic eruption dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Kieffer, S.W. [Arizona State Univ., Tempe, AZ (United States); Valentine, G.A. [Los Alamos National Lab., NM (United States); Woo, Mahn-Ling [Arizona State Univ., Tempe, AZ (United States)

    1995-06-01

    Our specific goals are to: (1) provide a set of models based on well-defined assumptions about initial and boundary conditions to constrain interpretations of observations of active volcanic eruptions--including movies of flow front velocities, satellite observations of temperature in plumes vs. time, and still photographs of the dimensions of erupting plumes and flows on Earth and other planets; (2) to examine the influence of subsurface conditions on exit plane conditions and plume characteristics, and to compare the models of subsurface fluid flow with seismic constraints where possible; (3) to relate equations-of-state for magma-gas mixtures to flow dynamics; (4) to examine, in some detail, the interaction of the flowing fluid with the conduit walls and ground topography through boundary layer theory so that field observations of erosion and deposition can be related to fluid processes; and (5) to test the applicability of existing two-phase flow codes for problems related to the generation of volcanic long-period seismic signals; (6) to extend our understanding and simulation capability to problems associated with emplacement of fragmental ejecta from large meteorite impacts.