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Sample records for cameroon volcanic line

  1. Late Cretaceous intraplate silicic volcanism in the Lake Chad region: incipient continental rift volcanism vs. Cameroon Line volcanism

    Science.gov (United States)

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

    2015-12-01

    The crustal evolution of west-central Africa during the Cretaceous was directly related to plate motion associated with the opening of the central Atlantic Ocean. Late Cretaceous (~66 Ma) to recent magmatism related to the Cameroon Line stretches from Northern Cameroon (i.e. Golda Zuelva) to the Gulf of Guinea (i.e. Pagalu) and is considered to be due to mantle-crust interaction. The volcanic rocks at Hadjer el Khamis, west-central Chad, are considered to be amongst the oldest volcanic rocks of the Cameroon Line but their relationship is uncertain because they erupted during a period of a regional extension associated with the opening of the Late Cretaceous (~75 Ma) Termit basin. The silicic volcanic rocks can be divided into a peraluminous group and a peralkaline group with both rock types having similar chemical characteristics as within-plate granitoids. In situ U/Pb zircon dating yielded a mean 206Pb/238U age of 74.4 ± 1.3 Ma and indicates the rocks erupted ~10 million years before the next oldest eruption attributed to the Cameroon Line. The Sr isotopes (i.e. ISr = 0.7050 to 0.7143) show a wide range but the Nd isotopes (i.e. 143Nd/144Ndi = 0.51268 to 0.51271) are more uniform and indicate that the rocks were derived from a moderately depleted mantle source. Major and trace elemental modeling show that the silicic rocks likely formed by shallow fractionation of a mafic parental magma where the peraluminous rocks experienced crustal contamination and the peralkaline rocks did not. The silicic rocks are more isotopically similar to Late Cretaceous basalts in the Doba and Bongor basins (i.e. ISr = 0.7040 to 0.7060; 143Nd/144Ndi = 0.51267 to 0.51277) of southern Chad than to rocks of the Cameroon Line (i.e. ISr = 0.7026 to 0.7038; 143Nd/144Ndi = 0.51270 to 0.51300). Given the age and isotopic compositions, it is likely that the silicic volcanic rocks of the Lake Chad area are related to Late Cretaceous extensional tectonics rather than to Cameroon Line magmatism.

  2. Nitrate contamination of groundwater in two areas of the Cameroon Volcanic Line (Banana Plain and Mount Cameroon area)

    Science.gov (United States)

    Ako, Andrew Ako; Eyong, Gloria Eneke Takem; Shimada, Jun; Koike, Katsuaki; Hosono, Takahiro; Ichiyanagi, Kimpei; Richard, Akoachere; Tandia, Beatrice Ketchemen; Nkeng, George Elambo; Roger, Ntankouo Njila

    2014-06-01

    Water containing high concentrations of nitrate is unfit for human consumption and, if discharging to freshwater or marine habitats, can contribute to algal blooms and eutrophication. The level of nitrate contamination in groundwater of two densely populated, agro-industrial areas of the Cameroon Volcanic Line (CVL) (Banana Plain and Mount Cameroon area) was evaluated. A total of 100 samples from boreholes, open wells and springs (67 from the Banana Plain; 33 from springs only, in the Mount Cameroon area) were collected in April 2009 and January 2010 and analyzed for chemical constituents, including nitrates. The average groundwater nitrate concentrations for the studied areas are: 17.28 mg/l for the Banana Plain and 2.90 mg/l for the Mount Cameroon area. Overall, groundwaters are relatively free from excessive nitrate contamination, with nitrate concentrations in only 6 % of groundwater resources in the Banana Plain exceeding the maximum admissible concentration for drinking water (50 mg/l). Sources of NO3 - in groundwater of this region may be mainly anthropogenic (N-fertilizers, sewerage, animal waste, organic manure, pit latrines, etc.). Multivariate statistical analyses of the hydrochemical data revealed that three factors were responsible for the groundwater chemistry (especially, degree of nitrate contamination): (1) a geogenic factor; (2) nitrate contamination factor; (3) ionic enrichment factor. The impact of anthropogenic activities, especially groundwater nitrate contamination, is more accentuated in the Banana Plain than in the Mount Cameroon area. This study also demonstrates the usefulness of multivariate statistical analysis in groundwater study as a supplementary tool for interpretation of complex hydrochemical data sets.

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

    Directory of Open Access Journals (Sweden)

    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.

  4. 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.

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

    Science.gov (United States)

    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.

  6. New thermoluminescence age estimates for the Nyos maar eruption (Cameroon Volcanic Line).

    Science.gov (United States)

    Schmidt, Christoph; Tchouankoue, Jean Pierre; Nkouamen Nemzoue, Peguy Noel; Ayaba, Félicité; Nformidah-Ndah, Siggy Signe; Nformi Chifu, Emmanuel

    2017-01-01

    Nyos maar is located in the Cameroon Volcanic Line and generates a multitude of primary and secondary hazards to the local population. For risk assessment and hazard mitigation, the age of the Nyos maar eruption provides some vital information. Since previous dating efforts using a range of techniques resulted in vastly varying eruption ages, we applied thermoluminescence (TL) methods to obtain independent and direct chronological constraints for the time of maar formation. Target minerals were granitic quartz clasts contained in pyroclastic surge deposits. Thermoluminescence plateau results prove that heat and/or pressure during the phreatomagmatic eruption was sufficient to reset the inherited luminescence signal of granitic bedrock quartz. Parallel application of three TL measurement protocols to one of the two samples gave consistent equivalent doses for the quartz ultra-violet emission. Despite the robustness of our dose estimates, the assessment of the dose rate was accompanied by methodological challenges, such as estimation of the original size distribution of quartz grains in the pyroclastic deposits. Considering results from additional laboratory analyses to constrain these uncertainties, we calculate an average maximum TL age of 12.3 ± 1.5 ka for the Nyos maar eruption. Based on these new data, a more solid risk assessment can be envisaged.

  7. New thermoluminescence age estimates for the Nyos maar eruption (Cameroon Volcanic Line.

    Directory of Open Access Journals (Sweden)

    Christoph Schmidt

    Full Text Available Nyos maar is located in the Cameroon Volcanic Line and generates a multitude of primary and secondary hazards to the local population. For risk assessment and hazard mitigation, the age of the Nyos maar eruption provides some vital information. Since previous dating efforts using a range of techniques resulted in vastly varying eruption ages, we applied thermoluminescence (TL methods to obtain independent and direct chronological constraints for the time of maar formation. Target minerals were granitic quartz clasts contained in pyroclastic surge deposits. Thermoluminescence plateau results prove that heat and/or pressure during the phreatomagmatic eruption was sufficient to reset the inherited luminescence signal of granitic bedrock quartz. Parallel application of three TL measurement protocols to one of the two samples gave consistent equivalent doses for the quartz ultra-violet emission. Despite the robustness of our dose estimates, the assessment of the dose rate was accompanied by methodological challenges, such as estimation of the original size distribution of quartz grains in the pyroclastic deposits. Considering results from additional laboratory analyses to constrain these uncertainties, we calculate an average maximum TL age of 12.3 ± 1.5 ka for the Nyos maar eruption. Based on these new data, a more solid risk assessment can be envisaged.

  8. New evidence for the asthenospheric origin of the Cameroon Volcanic Line from 1D shear wave velocities

    CSIR Research Space (South Africa)

    Tokam, AP

    2013-10-01

    Full Text Available structure of central Africa and the architecture of Precambrian lithosphere beneath the Congo Basin. In prep. Reusch, A.M., Nyblade, A.A., Wiens, D.A., Shore, P.J., Ateba, B., Tabod. C.T. and Nnange, J.M. 2010. Upper mantle structure beneath Cameroon... of Tertiary to Recent, generally alkaline, volcanoes stretching from the Atlantic island of Pagalu to the interior of the African continent (Lee et al. 1994). The line has been recently investigated using earthquake seismology data (Tabod et al., 1992...

  9. δ18O and δD variations in some volcanic lakes on the Cameroon Volcanic Line (West-Africa: generating isotopic baseline data for volcano monitoring and surveillance in Cameroon

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    . Issa

    2014-06-01

    Full Text Available Based on geo-anthropological and geochemical studies, catastrophes similar to the unprecedented gas explosions in the mid-1980s from the Cameroonian killer lakes Nyos and Monoun, might occur in any of the 37 other lakes located along the Cameroon Volcanic Line (CVL. Because people could suffer loss and desolation from predictable catastrophes in the future, monitoring/surveillance policies must be established. Due to their location, crater lakes integrate the geochemical processes that develop in the Earth’s crust due to magmatic activities. Therefore, monitoring the surface manifestations of those deep seated and/or hydrothermal processes might reveal increases/decreases in magmatic activities. The anomalous changes in a volcanic lake induced by mixing with exogenous fluids that have a specific δ18O and δD compositional fingerprint (magmatic, metamorphic, etc. could be utilized to predict volcanic hazards. If the steady state of a lake environment and the external and intrinsic parameters that control its hydrodynamics are clearly identified and reasonably understood, the anomalous evolutionary processes that compromise its stability can be identified. This study attempts to collect the δ18O and δD data from 17 Cameroonian lakes to help establish a volcano-related monitoring/surveillance network. This work identifies the processes that control the isotopic composition of the lakes and assesses the intra-/inter- and spatial δ18O/δD variations. Almost all of the lakes contain meteoric water. These lakes are mostly isotopically stratified; epilimnia is generally more positive than the hypolimnia. However, although the rainfall is gradually depleted in heavy isotopes when moving from the South to the North due to the latitude effect, the lakes become more enriched (0.6‰/100 km due to evaporation. The evaluated impact of several parameters on the isotopic variation suggests that the hydrological setting may play an important, albeit not

  10. Petrology of spinel lherzolite xenoliths from Youkou volcano, Adamawa Massif, Cameroon Volcanic Line: mineralogical and geochemical fingerprints of sub-rift mantle processes

    Science.gov (United States)

    Njombie, Merlin Patrick Wagsong; Temdjim, Robert; Foley, Stephen F.

    2018-02-01

    The basaltic maar of Youkou, situated in the Adamawa Volcanic Massif in the eastern branch of the continental segment of the Cameroon Volcanic Line, contains mantle-derived xenoliths of various types in pyroclastites. Spinel-bearing lherzolite xenoliths from the Youkou volcano generally exhibit protogranular textures with olivine (Fo89.4-90.5), enstatite (En89 - 91Fs8.7-9.8Wo0.82-1.13), clinopyroxene, spinel (Cr#Sp = 9.4-13.8), and in some cases amphibole (Mg# = 88.5-89.1). Mineral equilibration temperatures in the lherzolite xenoliths have been estimated from three-two pyroxene thermometers and range between 835 and 937 °C at pressures of 10-18 kbar, consistent with shallow mantle depths of around 32-58 km. Trends displayed by bulk-rock MgO correlate with Al2O3, indicating that the xenoliths are refractory mantle residues after partial melting. The degree of partial melting estimated from spinel compositions is less than 10%: evidences for much higher degrees of depletion are preserved in one sample, but overprinted by refertilization in others. Trace element compositions of the xenoliths are enriched in highly incompatible elements (LREE, Sr, Ba, and U), indicating that the spinel lherzolites underwent later cryptic metasomatic enrichment induced by plume-related hydrous silicate melts. The extreme fertility (Al2O3 = 6.07-6.56 wt% in clinopyroxene) and the low CaO/Al2O3 ratios in the spinel lherzolites suggest that they could not be a simple residue of partial melting of primitive mantle and must have experienced refertilization processes driven by the infiltration of carbonatite or carbonated silicate melts.

  11. Characterization of the sub-continental lithospheric mantle beneath the Cameroon volcanic line inferred from alkaline basalt hosted peridotite xenoliths from Barombi Mbo and Nyos Lakes

    Science.gov (United States)

    Pintér, Zsanett; Patkó, Levente; Tene Djoukam, Joëlle Flore; Kovács, István; Tchouankoue, Jean Pierre; Falus, György; Konc, Zoltán; Tommasi, Andréa; Barou, Fabrice; Mihály, Judith; Németh, Csaba; Jeffries, Teresa

    2015-11-01

    We carried out detailed petrographic, major and trace element geochemical, microstructural and FTIR analyses on eight characteristic ultramafic xenoliths from Nyos and Barombi Mbo Lakes in the continental sector of the Cameroon Volcanic Line (CVL). The studied xenoliths are spinel lherzolites showing lithologies similar to the other xenoliths reported previously along the CVL. They have protogranular and porphyroclastic textures. One of the Barombi xenolith contains amphibole, which had not been previously reported in this locality. Amphibole is common in the Nyos xenoliths suite. Peridotite xenoliths from both localities show some chemical heterogeneity, but Barombi xenoliths generally are less depleted in basaltic elements with respect to Nyos xenoliths. Trace element compositions of Nyos spinel lherzolites show a moderately depleted initial (premetasomatic) composition and variable enrichment in REE. Evidence for both modal and cryptic metasomatism is present in Nyos xenoliths. Rare earth element patterns of clinopyroxene suggest that interaction between mafic melts and the upper mantle occurred beneath the Nyos locality. Barombi Mbo xenoliths, on the other hand, record a small degree of partial melting. The Barombi Mbo xenoliths have weak, dominantly orthorhombic olivine crystal preferred orientations, whereas Nyos ones have strong axial-[010] patterns, which may have formed in response to transpression. Nominally anhydrous mantle minerals (NAMs) of the Barombi Mbo xenoliths show generally higher bulk concentrations of 'water' (70-127 ppm) than Nyos xenoliths (32-81 ppm). The Barombi Mbo xenoliths could originate from a juvenile segment of the lithospheric mantle, which had been originally part of the asthenosphere. It became a part of the lithosphere in response to thermal relaxation following the extension, forming a weakly deformed lower lithospheric mantle region along the CVL. The Nyos xenoliths, however, represent a shallow lithospheric mantle bearing

  12. Mount Oku, Cameroon Volcanic Line

    African Journals Online (AJOL)

    The peridotite has as minerals; plagioclases, spinel, olivine, and pyroxene The lavas show enrichment in LREE as compared to HREE ... These samples were decomposed, by lithium metaborate/lithium ..... Sm/Yb diagrams for determining the enrichment of the source and the partial melting degree of the mantle source.

  13. Volcanic Ash from the 1999 Eruption of Mount Cameroon Volcano ...

    African Journals Online (AJOL)

    Volcanic ash from the 1999 eruption of Mount Cameroon volcano has been characterized for its particle size and shape (by scanning electron microscopy, SEM), and mineralogy (by X-ray diffractometry, XRD). Also the total fluorine (F) content of the ash was determined by the selective ion electrode method. The results ...

  14. 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.

  15. Volcanic Ash from the 1999 Eruption of Mount Cameroon Volcano ...

    African Journals Online (AJOL)

    2008-10-21

    Oct 21, 2008 ... Economic Geology Unit, Department of Geology and Environmental Science, University of Buea, P.O. Box 63, Buea, South ..... mars 1999. Health Science and Disease 3, 62-63. Araya, O., Wittwer, F. and Villa, A., (1993): Evolution of fluoride concentrations in cattle and grass following a volcanic eruption.

  16. Volcanic risk perception in rural communities along the slopes of mount Cameroon, West-Central Africa

    Science.gov (United States)

    Njome, Manga S.; Suh, Cheo E.; Chuyong, George; de Wit, Maarten J.

    2010-11-01

    A study of volcanic risk perception was carried out in rural communities around the Mount Cameroon volcano between August and December 2008. The results indicate that risk perception reflects the levels of threat to which a resident population has been exposed to previously. Results of 70 responses to questionnaires show that local knowledge of hazards is high. Most respondents correctly indicated that earthquake and lava flow activities would affect resident population most in the future. By contrast, respondent's ability to adapt and protect themselves from the effects of future eruptions is poor, and inhabitants would likely shift responsibility for their protection to the requisite experts. This study confirms that there is little knowledge of any existing emergency plan, little or no educational outreach activities, but a high perceived need for information about and implementation of such actions. Knowledge about natural threats is found to be directly related to past exposure to volcanic hazard, and is significantly higher for people living along the southern than those along the northern slopes of Mt. Cameroon. The data also show that the media remains the most accessible channel for hazard communication, and that the internet is a growing information source that should be used to reach out to the younger generation. It is clear from the results of this study that major education and information efforts are required to improve the public's knowledge, confidence in the government, and growing self-reliance, in order to improve both collective and individual capacity to face future volcanic emergencies.

  17. 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.

  18. Radioactivity level and soil radon measurement of a volcanic area in Cameroon.

    Science.gov (United States)

    Ngachin, M; Garavaglia, M; Giovani, C; Kwato Njock, M G; Nourreddine, A

    2008-07-01

    The radioactivity level of soils in a volcanic area in Cameroon was determined and discussed. Thirty soils samples were collected from Buea and Limbé cities located in the south-western Cameroon. These two regions are known for theirs volcanic grounds due to the presence of Mount Cameroon Mountain. The activity concentrations of natural radionuclides as well as that of the fission product were evaluated by gamma-ray spectrometry using a hyper-purity germanium detector (HPGe). The ranges of concentrations in the surveyed soils were 11-17 Bq kg(-1), 22-36 Bq kg(-1) and 43-201 Bq kg(-1) for (226)Ra, (232)Th and (40)K, respectively. The radioisotope (137)Cs was also found but in a very small amount. The outdoor absorbed dose rate 1m above ground with the corresponding annual effective dose rate, assuming a 20% occupancy factor was estimated. The radium equivalent and the external hazard index were also evaluated and results are compared with available data from other studies and with the world average value [United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), 1988. Sources, Effects and Risks of Ionizing Radiation. Report to the General Assembly on the Effects of Atomic Radiation. United Nations, New York; UNSCEAR, 2000. Sources and Effects of Ionizing Radiations. Report to the General Assembly with Scientific Annexes. United Nations, New York]. A solid state nuclear track detector (SSNTD), LR-115 was used for soil radon measurements at a depth of 50 cm. The ranges of soil radon concentrations were 6.7-10.8 kBq m(-3) and 5.5-8.7 kBq m(-3) in Buea and Limbé, respectively. A positive correlation was found between concentrations of radium measured with gamma-spectrometry and the soil radon concentrations measured with the nitrate cellulose detectors. The results of this study provide the radioactivity level in soil of a volcanic area, which has been found to be within the safety limits. The south-western Cameroon can be considered as having

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

    Science.gov (United States)

    Gehl, P.; Quinet, C.; Le Cozannet, G.; Kouokam, E.; Thierry, P.

    2013-10-01

    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.

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

    Science.gov (United States)

    Gehl, P.; Quinet, C.; Le Cozannet, G.; Kouokam, E.; Thierry, P.

    2013-04-01

    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 events 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  2. Deep to shallow crustal differentiation of within-plate alkaline magmatism at Mt. Bambouto volcano, Cameroon Line

    Science.gov (United States)

    Marzoli, Andrea; Aka, Festus T.; Merle, Renaud; Callegaro, Sara; N'ni, Jean

    2015-04-01

    At Mt. Bambouto, a continental stratovolcano of the Cameroon Line, magmatic activity lasted for over 20 Ma and was characterized by at least two caldera formation events. Here we present detailed mineral and whole-rock compositions of Mt. Bambouto basanites, hawaiites, trachytes and phonolites, with emphasis on caldera related volcanic rocks. These data show that differentiation took place within a complex magma plumbing system, with magma chambers occurring at different depths within the crust. Though differentiation was chiefly dominated by fractional crystallization, chemical mineral zoning of olivines, clinopyroxenes, and feldspars is also indicative of open-system processes such as magma mixing and magma chamber recharge. Chemical zoning is evident mainly in the outer 100 microns of the analyzed crystals, suggesting that magma mixing occurred shortly before eruption. The last caldera collapse at about 15 Ma also marked a clear change in the magma plumbing system. Before caldera collapse, Mt. Bambouto was characterized by a dominant production of peralkaline quartz trachytic magmas in shallow magma chambers. During this phase, evolved basic magmas (hawaiites) and strongly evolved alkaline magmas were formed in middle and upper crustal magma chambers, respectively. After emptying of the shallow quartz trachytic magma chamber and caldera collapse, magmas from the deep magmatic plumbing system were mobilized and partially mixed. This triggered eruptions of magmas on the caldera rims.

  3. Geophysical evidence of Cretaceous volcanics in Logone Birni Basin (Northern Cameroon), Central Africa, and consequences for the West and Central African Rift System

    Science.gov (United States)

    Loule, Jean-Pierre; Pospisil, Lubomil

    2013-01-01

    Detailed analyses and interpretation realized by combining existing 2D reflection seismic and Gravity/Magnetic data of the Logone Birni Basin (LBB) in the West and Central African Rift System (WCAS) have revealed the distribution of the main buried volcanic bodies as well as their relationships with the structural and tectonic evolution of this basin. The volcanic activity in the LBB is restricted to the Cretaceous period. Three main volcanic episodes are identified and are associated to the Neocomian, Late Albian and Cenomanian-Turonian rifting phases respectively. The volcanic bodies within the Lower Cretaceous are either lying directly on basement or are mainly interbedded with the contemporaneous sediments whereas the Upper Cretaceous bodies are morphologically expressed in the forms of dykes and sills. The volcanic activity was more intense in the western region of the central LBB (Zina sub-basin) along the Cameroon-Nigeria border whereas it was scanty and scattered in the other parts of the basin. The main volcanic dykes are found on the flanks of the major faults bounding basement horsts or in crestal positions in association with syndepositional faults. Although WCAS is associated with large amount of crustal extension and minor volcanism, the intense volcanic activity observed in LBB during the Cretaceous suggests that the intrusive zone during this period was confined to the basement beneath the study area flanked respectively to the north, south and southwest by the Lake Chad, Poli and Chum triple junctions. Tensional stresses generated by this localized domal uplift accounts for most of the observed tectonic structures where major faults transected the entire lithosphere, thus providing conduits for magma migration.

  4. The amphibians of Mount Oku, Cameroon: an updated species inventory and conservation review

    Czech Academy of Sciences Publication Activity Database

    Doherty-Bone, T. M.; Gvoždík, Václav

    2017-01-01

    Roč. 643 (2017), s. 109-139 ISSN 1313-2989 R&D Projects: GA ČR GJ15-13415Y Institutional support: RVO:68081766 Keywords : Biodiversity * caecilians * Cameroon Volcanic Line * Central Africa * frogs * Lake Oku * montane forests and grasslands Subject RIV: EG - Zoology Impact factor: 1.031, year: 2016

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

    Science.gov (United States)

    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

  6. 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

  7. Coastal Zone of Cameroon

    African Journals Online (AJOL)

    komla

    A biogeochemical model of water, salt and nutrients budgets for two estuarine systems within Cameroon's coastal zone (Latitudes 2°— 1 3°N, Longitudes ... along ecological food webs and the earth's along an approximate 25,000 km along ...... Cameroon. Cameroon Wildlife and. Conservation Society Consultancy Report.

  8. First-line antiretroviral therapy and dyslipidemia in people living with HIV-1 in Cameroon: a cross-sectional study

    Directory of Open Access Journals (Sweden)

    Kengne André

    2011-09-01

    Full Text Available Abstract Background Data on lipid profile derangements induced by antiretroviral treatment in Africa are scarce. The aim of this study was to determine the prevalence and characteristics of lipid profile derangements associated with first-line highly active antiretroviral therapy (ART among Cameroonians living with human immunodeficiency virus (HIV infection. Methods This cross-sectional study was conducted between November 2009 and January 2010, and involved 138 HIV patients who had never received ART (ART-naive group and 138 others treated for at least 12 months with first line triple ART regimens that included nevirapine or efavirenz (ART group. Lipid profile was determined after overnight fast and dyslipidemia diagnosed according to the US National Cholesterol Education Program III criteria. Data comparison used chi-square test, Student t-test and logistic regressions. Results The prevalence of total cholesterol ≥ 200 mg/dl was 37.6% and 24.6% respectively in ART group and ART-naive groups (p = 0.019. The equivalents for LDL-cholesterol ≥ 130 mg/dl were 46.4% and 21% (p ≤ 0.001. Proportions of patients with total cholesterol/HDL-cholesterol ratio ≥ 5 was 35.5% in ART group and 18.6% in ART-naive group (p ≤ 0.001. The distribution of HDL-cholesterol and triglycerides was similar between the two groups. In multivariable analysis adjusted for age, sex, body mass index, CD4 count and co-infection with tuberculosis, being on ART was significantly and positively associated with raised total cholesterol, LDL-cholesterol and TC/HDL cholesterol. The adjusted odd ratios (95% confidence interval, p-value ART-treated vs. ART-naïve was 1.82 (1.06-1.12, p = 0.02 for TC ≥ 200 mg/dl; 2.99 (1.74-5.15, p Conclusions First-line antiretroviral therapy that includes nonnucleoside reverse transcriptase inhibitors is associated with pro-atherogenic adverse lipid profile in people with HIV-1 infection compared to untreated HIV-infected subjects in

  9. African Journals Online: Cameroon

    African Journals Online (AJOL)

    Items 1 - 8 of 8 ... The Cameroon Journal of Experimental Biology is the official journal of the Cameroon Forum for Biological Sciences (CAFOBIOS). ... It is intended to provide locally and internationally relevant updates to the clinical practice of Obstetrics, Gynaecology and Pediatrics while touching on the broader public health ...

  10. Country report Cameroon

    Energy Technology Data Exchange (ETDEWEB)

    Tagne, E.

    2007-07-01

    The author of the contribution under consideration reports on the history of activities in biogas projects in Cameroon. The first projects started in the year 1978. The latest projects are concerned to an anaerobic sanitation system Cameroon (ASSC) biogas plant at different places in Cameroon. Problems arise from a weak cooperation between project beneficiary and project officers as well as from irregular supply of building materials. Direct consequences of such project will be the creation of job opportunities, improvement of health, education and training of youths from nursery to high schools, also contractors and local artisans for the use of anaerobic systems to the detriment of septic tanks.

  11. Crust-mantle coupling mechanism in Cameroon, West Africa, revealed by 3D S-wave velocity and azimuthal anisotropy

    Science.gov (United States)

    Ojo, Adebayo Oluwaseun; Ni, Sidao; Chen, Haopeng; Xie, Jun

    2018-01-01

    To understand the depth variation of deformation beneath Cameroon, West Africa, we developed a new 3D model of S-wave isotropic velocity and azimuthal anisotropy from joint analysis of ambient seismic noise and earthquake surface wave dispersion. We found that the Cameroon Volcanic Line (CVL) is well delineated by slow phase velocities in contrast with the neighboring Congo Craton, in agreement with previous studies. Apart from the Congo Craton and the Oubanguides Belt, the uppermost mantle revealed a relatively slow velocity indicating a thinned or thermally altered lithosphere. The direction of fast axis in the upper crust is mostly NE-SW, but trending approximately N-S around Mt. Oku and the southern CVL. The observed crustal azimuthal anisotropy is attributed to alignment of cracks and crustal deformation related to magmatic activities. A widespread zone of weak-to-zero azimuthal anisotropy in the mid-lower crust shows evidence for vertical mantle flow or isotropic mid-lower crust. In the uppermost mantle, the fast axis direction changed from NE-SW to NW-SE around Mt. Oku and northern Cameroon. This suggests a layered mechanism of deformation and revealed that the mantle lithosphere has been deformed. NE-SW fast azimuths are observed beneath the Congo Craton and are consistent with the absolute motion of the African plate, suggesting a mantle origin for the observed azimuthal anisotropy. Our tomographically derived fast directions are consistent with the local SKS splitting results in some locations and depths, enabling us to constrain the origin of the observed splitting. The different feature of azimuthal anisotropy in the upper crust and the uppermost mantle implies decoupling between deformation of crust and mantle in Cameroon.

  12. Country watch: Cameroon.

    Science.gov (United States)

    Epanya, A; Delude, B R

    1996-01-01

    Education for Life and Love, a program initiated by Cameroon's Catholic Health Service, seeks to reach young people with educational messages that encourage responsible sexual behavior. Nearly 280,000 students attend Cameroon's 1200 Catholic primary and secondary schools. Sex education is introduced in the third year of primary school (ages 9-10 years) and continues through secondary school; out-of-school Catholic youth are reached through church workshops and youth groups. The sex education curriculum includes communication skills and the promotion of respect between males and females, as well as factual information on adolescent pregnancy, sexually transmitted diseases, and acquired immunodeficiency syndrome. Outreach to parents seeks to alleviate their concerns that sex education promotes early sexual activity. Cameroon Catholic youth face ongoing tensions between the media's romanticization of premarital sex and the Church's efforts to encourage self-control and responsible choices.

  13. IDRC in Cameroon

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

    IDRC has been supporting research in Cameroon since 1976. The Centre's funding has enabled researchers, for example, to provide concrete infor- mation that eased women's access to health services, enhance the use of computers and the Internet in schools, and help the country's teachers' colleges integrate ...

  14. CAMEROON FIGHTING BOKO HARAM

    Directory of Open Access Journals (Sweden)

    Ж КЖ Кума

    2017-12-01

    Full Text Available This study proposes to retrace Boko Haram atrocities in Cameroon as well as the history of international cooperation against the Islamist sect since the declaration of the war against it in 2014. The principal internal counter-terrorist efforts are shown, including establishement of “Operational Com-mand” missions, partial reorganization of the territorial map of the army’s command, the expansion of defense policy at the subregional level and the gradual redefinition of military, the allocation of re-sources and tools adapted to these new missions. Cameroon engages in a process of multilateralization of the challenges of counter-terrorism coopera-tion, which gives a new dimension to the action of the defense and security forces as well as the multi-lateralization of the stakes of cooperation. The role of major powers and the countries of the subregion as well as the African Union and the United Nations is revealed. Cameroon is a traditional beneficiary of French military assistance. Counter-terrorist assistance also came from Russia, US, UK and Germany. The role of the Multinational Joint Task Force of Commission of the Lake Chad Basin (LCBC is shown. The author also shows that the war against Boko Haram seems to produce exceptional results that force both admiration and criticism of the Cameroonian people and the international community. The case of criticism by the NGO Amnesty International is analysed in details.

  15. Cameroon Journal of Experimental Biology

    African Journals Online (AJOL)

    The Cameroon Journal of Experimental Biology is the official journal of the Cameroon Forum for Biological Sciences (CAFOBIOS). It is an interdisciplinary journal for the publication of original research papers, short communications and review articles in all fields of experimental biology including biochemistry, physiology, ...

  16. Journal of the Cameroon Academy of Sciences - Vol 8, No 2-3 (2009)

    African Journals Online (AJOL)

    Volcanic Ash from the 1999 Eruption of Mount Cameroon Volcano: Characterization and Implications to Health Hazards · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. MBS Atanga, AS Van der Meerve, EM Shemamg, CE Suh, W Kruger, MS Njome, NE Asobo, 63- ...

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

    Science.gov (United States)

    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.

  18. Cameroon Journal of Agricultural Science

    African Journals Online (AJOL)

    Journal Camerounais des Sciences Agricoles The Cameroon Journal of Agricultural Science publishes new information on all aspects of agricultural science – agronomy, breeding, crop protection, economics, rural sociology, forestry and animal science, health and production ...

  19. The use of luminescence for dating young volcanic eruptions

    Science.gov (United States)

    Schmidt, Christoph; Schaarschmidt, Maria; Kolb, Thomas; Richter, Daniel; Tchouankoue, Jean Pierre; Zöller, Ludwig

    2017-04-01

    Reliable chronologies of volcanic eruptions are vital for hazard analysis, but dating of Holocene and Late Pleistocene volcanism poses a major challenge. Established techniques such as 40Ar/39Ar are often problematic due to the long half-life of 40K or the absence of datable materials. In this context, luminescence dating methods are an alternative since they are applicable to Earth's most common minerals and to a range of different datable events. Luminescence signal resetting during volcanic activity can be caused by heat (lava, contact to lava), light (disintegration of ejecta) or (temperature-assisted) pressure in the course of phreatomagmatic explosions. While volcanogenic minerals assembling basalt or other volcanic rocks are less suitable for luminescence dating due to so-called anomalous fading, the signal of volcanogenically heated or fragmented country rock actually relates to the time of eruption as well and further provides reproducible results. This contribution aims to illustrate the potential of this latter approach by presenting two case studies. The first refers to two Late Pleistocene scoria cones in the Westeifel Volcanic Field (WEVF), Germany, of which the Wartgesberg locality was dated by 40Ar/39Ar and 14C, while the closeby Facher Höhe is chronologically poorly constrained (Mertz et al. 2015; pers comm. Luise Eichhorn, 2016). The former locality allows testing the accuracy of various luminescence techniques (thermoluminescence, TL, optically stimulated luminescence, OSL, infrared stimulated luminescence, IRSL) applied to quartz and feldspar against independent age control. The other study site is the monogenetic Lake Nyos Maar as part of the Cameroon Volcanic Line, having killed 1,700 people in 1986 following the release of large amounts of CO2. Previous dating efforts of the last explosive activity are inconsistent and yielded age estimates ranging from 400 a (14C) to >350 ka (K-Ar) (Aka et al. 2008). Our results demonstrate that multiple

  20. Cameroon Journal of Experimental Biology: Submissions

    African Journals Online (AJOL)

    Author Guidelines. Instructions to Authors The Cameroon Journal of Experimental Biology (Cameroon J. Exp. Biol.) welcomes contributions in all fields of experimental biology including biochemistry, physiology, pharmacology, toxicology, pathology, environmental biology, microbiology, parasitology, phytochemistry, food ...

  1. Sustainable development in Cameroon's forestry sector: Progress ...

    African Journals Online (AJOL)

    EJIRO

    This paper examines initiatives formulated by the government of Cameroon to promote sustainable development within its forestry sector, and proffers a series of policy recommendations for advancing sustainable forest management in Cameroon. Since the enactment of Cameroon's comprehensive forestry law (Law N0.

  2. Widowhood in contemporary Anglophone Cameroon literature

    African Journals Online (AJOL)

    2016-03-28

    Mar 28, 2016 ... Widowhood in contemporary Anglophone. Cameroon Literature. Moving from the premise that widows have been at the margins of literary discourse in Cameroon, this paper examines widow- hood in contemporary Anglophone Cameroon literature using John Nkemngong Nkengasong's The Widow's ...

  3. 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

  4. Volcanic Gas

    Science.gov (United States)

    ... often escape continuously into the atmosphere from the soil, volcanic vents , fumaroles , and hydrothermal systems. By far the ... after falling into a snow depression surrounding a volcanic fumarole and filled ... of CO 2 gas in soils can also damage or destroy vegetation, as is ...

  5. Promotion and Development of Tourism in Cameroon

    OpenAIRE

    Frida-Tolonen, Frida

    2014-01-01

    This Bachelor’s thesis is aimed to achieve a main goal which is at Promoting and developing tourism in Cameroon. This work will give a broad overview of issues in tourism in Africa and Cameroon, suggesting guidelines to assist countries such as Cameroon, Namibia, Nigeria, to develop a more coherent structure for tourism. Tourism can only develop sustainably if it is united into the country’s overall economic, social and physical planning policies and enhancing regional promotion and effective...

  6. Recruitment Of International Students Into Cameroon Tertiary ...

    African Journals Online (AJOL)

    This paper highlights the importance of Cameroon\\'s tertiary institutions\\' cooperation links with other African Universities given the rebirth of Organisation of African Unity as African Union, and the New Partnership for Africa Development (NEPAD). The present system of recruiting international students is haphazardly been ...

  7. Chieftaincy and privatisation in Anglophone Cameroon

    NARCIS (Netherlands)

    Konings, P.J.J.; Binsbergen, van W.M.J.; Pelgrim, R.

    2003-01-01

    This chapter examines the opposition of Bakweri chiefs in Anglophone Cameroon to the government announcement, on 15 July 1994, of the privatization of the Cameroon Development Corporation (CDC), one of the oldest and largest agroindustrial parastatals of the country. The chiefs claimed Bakweri

  8. Understanding poverty-related diseases in Cameroon from a salutogenic perspective

    NARCIS (Netherlands)

    Makoge, Valerie

    2017-01-01

    Poverty-related diseases (PRDs) assume poverty as a determinant in catching disease and an obstacle for cure and recovery. In Cameroon, over 48 % of the population lives below the poverty line. This dissertation starts from the premise that the relation between poverty and disease is mediated by

  9. University Strategic Planning in Cameroon

    Directory of Open Access Journals (Sweden)

    Terfot Augustine Ngwana

    2003-12-01

    Full Text Available This article argues that the global, regional, and local realities can complement rather than contradict each other in the process of strategic planning for universities in Sub-Saharan Africa (SSA. Using the case of the University of Buea in Cameroon, it attempts to use the global trends of polarisation in knowledge production capacity as an input or tool for identifying strategic choice in the process of strategic planning in institutions. The national policy background is used to highlight the context and inherent role of the central government in the process of institutional strategic planning.

  10. 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.

  11. Analogue modelling of deformation structures at Mt Cameroon analysed with a digital image correlation technique

    Science.gov (United States)

    Kervyn, Matthieu; Walter, Thomas R.; van Wyk de Vries, Benjamin; Ernst, Gerald G. J.

    2010-05-01

    Mt. Cameroon is a large, 4090 m high, continental volcano. It is characterized by repetitive basaltic lava flow eruptions, the most recent ones occurring in 1999 and 2000. Upper flanks of Mt Cameroon are exceptionally steep (~30°) for a lava-dominated volcano and are constrained by sharp breaks-in-slope. Field work enabled to identified well-defined inward-dipping structures bordering a flat summit plateau and thrust faults associated with topographic terraces around Mt Cameroon's base, suggesting summit subsidence and gravitational spreading of the volcano flanks above its sedimentary base. To better understand the structural configuration and morphology observed, scaled analogue experiments were designed. A volcanic ridge, made out of fine quartz sand, was let spread under gravitational forces above a ductile silicone layer. Experiments were conducted in 2D and 3D configurations. A digital image correlation (DIC) procedure was used to record fault formation and evolution through time. 3D spreading of an elongated edifice favors displacement perpendicular to the long axis, and formation of a summit graben and basal thrusts or folds parallel to this axis. Results of the DIC highlights the strain concentration in the central part of the main graben and along specific strike-slip faults bordering secondary grabens. This deformation is however not associated with slope increase or instabilities. 2D spreading of a volcanic ridge between two glass panes is associated either with two outward-dipping listric normal faults and inward-dipping antithetic faults or with two sets of deep and shallow normal faults, defining a central graben and forming steep mid-slopes with local instabilities, depending on the thickness of the underlying ductile material. Results from the experiments are compared with structural lineaments mapped at Mt Cameroon. It is concluded that the elongated morphology of Mt Cameroon promotes directional spreading perpendicular to its long axis, probably

  12. FRIENDSHIP AMONG PASTORAL FULBE IN NORTHWEST CAMEROON

    OpenAIRE

    Pelican, Michaela

    2012-01-01

    This article discusses perceptions and practices of friendship among the Mbororo (pastoral Fulbe) in northwest Cameroon. The concept of friendship is culturally and socially embedded, and the author highlights the flexible and multilayered character of friendship in Cameroon. While in Europe and the U.S. the voluntary and emotional connotations of friendship are stressed, for the Mbororo, it includes a significant economic component and may overlap with other relationships, such as kinship an...

  13. [The demographic situation in Cameroon].

    Science.gov (United States)

    Njeck, R A

    1984-01-01

    The population census in 1976 and the Cameroon Fertility Survey (CFS) of 1978 have allowed the population profile of Cameroon to be better known, but data are still scarce on many topics. Several hypotheses were adopted for the elaboration of population estimates for 1983: mortality was assumed constant between 1976-86 despite constant improvements in the health infrastructure, fertility was assumed to be constant despite increases over the previous 2 decades, net migration was assumed to be negligible, and different structures such as education and employment were assumed constant in the absence of data. The population of Cameroon was estimated at about 9,540,000 as of June 1984. 42.8% was under 15 years of age. Children of school age (6-14 years) represented 23.7% of the total population, and 4.9% was over 60 years of age. The masculinity ratio was 99.6. In some rural areas the sex ratio was under 70 between ages 20-30. According to the 1976 census, in 1976 among men and women respectively, 39.5 and 15.9% were single, 55.8% and 66.8% were married, 2.1% and 13.9% were widowed, and 2.6% and 3.4% were divorced. According to CFS data, among men and women in 1978, 36.0% and 13.6% were single, 58.5% and 69.6% were married, 2.2% and 13.5% were widowed, and 3.0% and 3.6% were divorced. CFS data indicated that 63% of women and 46% of men had never attended school. 39.9% of the population was economically active in 1976. Unemployment reached 17.2% in urban areas and 4.3% in rural areas. The birth rate increased from 43/1000 in 1960-65 to 45/1000 in 1976. The mortality rate declined from 23/1000 in 1960-65 to 20/1000 in 1976, and life expectancy at birth increased from 37.5 to 44.6 in the same period (47 years for women and 42.3 for men). The infant mortality rate was 113/1000 in 1978, and the rate of natural increase was estimated at 2.5%.

  14. 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.

  15. The Effects of Sustainable Tourism on the Pygmies of Cameroon

    OpenAIRE

    Njenji, Julius

    2014-01-01

    The Cameroon Pygmies like many indigenous groups of the World are facing threats and marginalization or discrimination on the land they first possessed by their neighboring farmer´s group known as, the Bantus and the Cameroon Government policies as a result of tourism development. This study examines The Effects of Sustainable Tourism on the Pygmies of Cameroon as the government pushes its policy to invest more in tourism, hoping to make Cameroon a tourist destination by 2035. The tourism gro...

  16. Anglophone Cameroon literature: A conversation with Bole Butake

    African Journals Online (AJOL)

    2016-03-28

    Mar 28, 2016 ... a missing entity. People like Professor Fonlon, Sankie Maimo; the creation of. Cameroon Tribune, and so on. Cameroonians started writing in the newspapers, especially Cameroon Tribune, and Fonlon tried to justify why anglophones were not writing literature. He published an article in Cameroon Tribune ...

  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. 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.

  19. LINES

    Directory of Open Access Journals (Sweden)

    Minas Bakalchev

    2015-10-01

    Full Text Available The perception of elements in a system often creates their interdependence, interconditionality, and suppression. The lines from a basic geometrical element have become the model of a reductive world based on isolation according to certain criteria such as function, structure, and social organization. Their traces are experienced in the contemporary world as fragments or ruins of a system of domination of an assumed hierarchical unity. How can one release oneself from such dependence or determinism? How can the lines become less “systematic” and forms more autonomous, and less reductive? How is a form released from modernistic determinism on the new controversial ground? How can these elements or forms of representation become forms of action in the present complex world? In this paper, the meaning of lines through the ideas of Le Corbusier, Leonidov, Picasso, and Hitchcock is presented. Spatial research was made through a series of examples arising from the projects of the architectural studio “Residential Transformations”, which was a backbone for mapping the possibilities ranging from playfulness to exactness, as tactics of transformation in the different contexts of the contemporary world.

  20. Assessing Public Attitudes and Behaviour to Household Waste Management in Cameroon to Drive Strategy Development: A Q Methodological Approach

    Directory of Open Access Journals (Sweden)

    Lawrence O. Mbeng

    2009-09-01

    Full Text Available Household waste is an environmental and public health problem, especially for the large cities in Sub-Saharan African countries. While the improper management of household waste in Cameroon is linked to the systematic failure of policy makers and municipal authorities to identify the most sustainable ways of dealing with it in such a manner that is in line is with their socio-economic aspirations, the impact of public attitudes and behaviour has been neglected. It is in this context that this paper uses Q-methodology, a powerful methodology for identifying the different trends in behaviour in the management of household waste in Douala, Cameroon.

  1. Widowhood in contemporary Anglophone Cameroon literature

    African Journals Online (AJOL)

    2016-03-28

    Mar 28, 2016 ... hood in contemporary Anglophone Cameroon literature using John Nkemngong Nkengasong's The Widow's Might (2006) and ..... girl, namely, neglecting her studies for a life of promiscuity. ..... Nwajiaku, Ijioma C. “Representation of the Womanist Discourse in the Short Fiction of Akachi Ezeigbo and.

  2. Journal of the Cameroon Academy of Sciences

    African Journals Online (AJOL)

    Revue de L'academie des Sciences du Cameroun The Journal of the Cameroon Academy of Sciences is a multi-disciplinary publication devoted to all aspects of fundamental and applied research. It also publishes topical reviews on science and technology in development, arts, humanities and culture.

  3. IRON BIOAVAILABILITY IN CAMEROON WEANING FOODS AND ...

    African Journals Online (AJOL)

    The objective of the study was to assess the "in vitro" bioavailability of iron in the main Cameroon traditional complementary foods identified during interviews of one month with 91 mothers of weaning babies of up to 30 months, in order to identify and select good food sources of iron to fight against iron deficiency and iron ...

  4. The Bildungsroman in Cameroon Anglophone Literature: John ...

    African Journals Online (AJOL)

    This paper investigates the bildungsroman genre in postcolonial Cameroon Anglophone fiction through a textual analysis of John Nkemngong Nkengasong's Across the Mongolo and Margaret Afuh's Born before Her Time. It seeks to show that these two writers have borrowed a foreign genre and successfully manipulated ...

  5. State-space approach to evaluate spatial variability of field measured soil water status along a line transect in a volcanic-vesuvian soil

    Directory of Open Access Journals (Sweden)

    A. Comegna

    2010-12-01

    Full Text Available Unsaturated hydraulic properties and their spatial variability today are analyzed in order to use properly mathematical models developed to simulate flow of the water and solute movement at the field-scale soils. Many studies have shown that observations of soil hydraulic properties should not be considered purely random, given that they possess a structure which may be described by means of stochastic processes. The techniques used for analyzing such a structure have essentially been based either on the theory of regionalized variables or to a lesser extent, on the analysis of time series. This work attempts to use the time-series approach mentioned above by means of a study of pressure head h and water content θ which characterize soil water status, in the space-time domain. The data of the analyses were recorded in the open field during a controlled drainage process, evaporation being prevented, along a 50 m transect in a volcanic Vesuvian soil. The isotropic hypothesis is empirical proved and then the autocorrelation ACF and the partial autocorrelation functions PACF were used to identify and estimate the ARMA(1,1 statistical model for the analyzed series and the AR(1 for the extracted signal. Relations with a state-space model are investigated, and a bivariate AR(1 model fitted. The simultaneous relations between θ and h are considered and estimated. The results are of value for sampling strategies and they should incite to a larger use of time and space series analysis.

  6. Elephantiasis of non-filarial origin (podoconiosis) in the highlands of north-western Cameroon.

    Science.gov (United States)

    Wanji, S; Tendongfor, N; Esum, M; Che, J N; Mand, S; Tanga Mbi, C; Enyong, P; Hoerauf, A

    2008-09-01

    Lymphoedema, a condition of localized fluid retention, results from a compromised lymphatic system. Although one common cause in the tropics is infection with filarial worms, non-filarial lymphoedema, also known as podoconiosis, has been reported among barefoot farmers in volcanic highland zones of Africa, Central and South America and north-western India. There are conflicting reports on the causes of lymphoedema in the highland regions of Cameroon, where the condition is of great public-health importance. To characterise the focus of lymphoedema in the highlands of the North West province of Cameroon and investigate its real causes, a cross-sectional study was carried out on the adults (aged > or =15 years) living in the communities that fall within the Ndop and Tubah health districts. The subjects, who had to have lived in the study area for at least 10 years, were interviewed, examined clinically, and, when possible, checked for microfilaraemia. The cases of lymphoedema confirmed by ultrasonography and a random sample of the other subjects were also tested for filarial antigenaemia. The interviews, which explored knowledge, attitudes and perceptions (KAP) relating to lymphoedema, revealed that the condition was well known, with each study community having a local name for it. Of the 834 individuals examined clinically, 66 (8.1%) had lymphoedema of the lower limb, with all the clinical stages of this condition represented. None of the 792 individuals examined parasitologically, however, had microfilariae of W. bancrofti (or any other filarial parasite) in their peripheral blood, and only one (0.25%) of the 399 individuals tested for the circulating antigens of W. bancrofti gave a positive result. In addition, none of the 504 mosquitoes caught landing on human bait in the study area and dissected was found to harbour any stage of W. bancrofti. These findings indicate that the elephantiasis seen in the North West province of Cameroon is of non-filarial origin.

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

    Indian Academy of Sciences (India)

    2014-07-16

    Jul 16, 2014 ... which can be explained by poverty, lack of employment and economic crisis, to name a few (Fleisher 2007). Traditionally, the principal income-generating activities in Cameroon are trade and agriculture. In the migration from Cameroon to. Germany, for example, Cameroonian migrants constitute the.

  8. Colonial Bilingual Heritage and Post-Colonial Myths in Cameroon's ...

    African Journals Online (AJOL)

    This article examines Cameroon's bilingual heritage and describes post-colonial attitudes and tendencies towards language and language use in the country's educational system. The intent is to show that Cameroon's bilingual heritage - a colonial legacy - has led to an unnecessary and chaotic national competition among ...

  9. Money Supply, Interest Rate, and Economic Growth in Cameroon: A ...

    African Journals Online (AJOL)

    ... expansionary monetary policy in Cameroon. This work therefore recommends guided expansionary monetary policy as an instrument for growth and development in Cameroon in particular and the CEMAC zone in general. Key words: Dynamic, Money Supply, Interest Rates, Economic growth, Co-integration and Inflation.

  10. Francophone Cameroon literature: A conversation with Ambroise Kom

    African Journals Online (AJOL)

    2016-03-28

    Mar 28, 2016 ... You have had an illustrious academic career in Cameroon, France, the United States. You retired from the College of the Holy Cross and came back home. Before we talk about Francophone. Cameroon Literature, can we begin with what you're doing now? To tell you what I am doing today would be a long ...

  11. Customary courts' system in West Cameroon: reforms and conflict ...

    African Journals Online (AJOL)

    It further held that it continued without any interference from the Federal Government in West Cameroon until 1966, when the former favoured reforms that could reduce their authority (Customary Courts). It called for the reduction of their powers and a transfer of the control of these institutions from West Cameroon Ministry of ...

  12. Nexus of conflict reporting: Analysis of Cameroon newspaper ...

    African Journals Online (AJOL)

    The Post Newspaper and Cameroon Tribune from July 2014 to December 2014 were content analyzed to examine the level of prominence, the angle and proximity of the stories covered on the said cross border conflicts. Findings reveal that the coverage of these conflicts by Cameroon Tribune and the Post Newspaper ...

  13. Anglophone Cameroon literature 1959–90: A brief overview ...

    African Journals Online (AJOL)

    This article examines modern Anglophone Cameroon literature from 1959 to 1990. The article argues that like most literature emanating from the continent a proper understanding of Anglophone Cameroon literature must be predicated on an analysis of its specific socio-historical determinants. A careful analysis of the ...

  14. The role of women's secret societies in cameroon's contemporary ...

    African Journals Online (AJOL)

    Although there are many secret societies, most of which belong to the male folk in the North West Province of Cameroon, little was and/or is known about their activities. However, Takumbeng, a women's secret society from the North West Province of Cameroon came to prominence in the 1990's during the political upheaval ...

  15. Determinants of Inequality in Cameroon: A Regression-Based ...

    African Journals Online (AJOL)

    This paper applies the regression-based inequality decomposition approach to explore determinants of income inequality in Cameroon using the 2007 Cameroon household consumption survey. The contribution of each source to measured income inequality is the sum of its weighted marginal contributions in all possible ...

  16. 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

  17. Cameroon Journal of Agricultural Science - Vol 3, No 2 (2007)

    African Journals Online (AJOL)

    Effects of burning intensity on soil water storage and transmission characteristics in an Ultisol under cropping in Southern Cameroon · EMAIL FULL TEXT EMAIL FULL ... Countrywide distribution of fauna associated with the cassava green mite (Mononychellus tanajoa) in Cameroon · EMAIL FULL TEXT EMAIL FULL TEXT

  18. Reactions of some potato genotypes to late blight in Cameroon ...

    African Journals Online (AJOL)

    Reactions of some potato genotypes to late blight in Cameroon. D. K. Njualem, P. Demo, H. A. Mendoza, J. T. Koi, S. F. Nana. Abstract. Field experiments were conducted in Cameroon in 1995 and 1996 to evaluate reactions of different potato genotypes to late blight. There were significant differences among genotypes for ...

  19. Cholera public health surveillance in the Republic of Cameroon ...

    African Journals Online (AJOL)

    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 ...

  20. Poverty and malnutrition in Cameroon | Fambon | African Journal of ...

    African Journals Online (AJOL)

    Over the past decades, child malnutrition has persisted at high rates in many developing countries including Cameroon. This research attempts to evaluate the levels and characteristics of the malnutrition affecting children in Cameroon by using the anthropometrics data gathered during the 1998 Demographic Health ...

  1. Analysis of Cameroon's forestry sector: Implication for sustainable ...

    African Journals Online (AJOL)

    Cameroon forestry sector has undergone profound institutional and legislative reforms for the past decades. Consequently, the objective of this paper is to examine the activities of Cameroon administration focused on the strategies for sustainable management of the forestry sector. The target population for achieving this ...

  2. 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.

  3. Silent circulation of arboviruses in Cameroon.

    Science.gov (United States)

    Fokam, E B; Levai, L D; Guzman, H; Amelia, P A; Titanji, V P K; Tesh, R B; Weaver, S C

    2010-06-01

    To investigate the silent circulation and transmission of arthropod-borne viruses (arboviruses) in the Fako Division of Cameroon. This survey was conducted based on clinical observations and laboratory diagnosis; field collections of mosquitoes. This study was conducted in the Fako Division of South West Cameroon. One hundred and two sera were obtained from febrile patients (with negative laboratory findings for malaria and typhoid fever) at clinics in the Fako Division, and diurnal anthropophilic mosquitoes (4,764) collected. Virus isolation was attempted from these, and sera were screened for antibodies against 18 African arboviruses by haemagglutination inhibition (HI) and complement fixation (CF) tests. No virus was isolated. Fifty three of 79 (67.1%) sera reacted with one or more viral antigens. Twenty nine sera (36.7%) reacted with members of the genus Alphavirus, with Chikungunya (CHIKV) and O'nyong-nyong (ONNV) viruses as the most frequent (34.2%). Forty six sera (58.2%) reacted with members of the genus Flavivirus: 24 (30.4%) were cross-reactive, but 11.4% reacted monotypically with Zika, 5.1% with yellow fever virus (YFV), 5.1% with dengue virus-2 (DENV-2), 2.5% with DENV-1 and 1.3% with Wesselsbron virus, respectively. The plaque reduction neutralisation test used to specify the agent that elicited the response could not resolve 33.3% of the cross reactions between CHIKV and ONNV. Neutralising antibody titres against ONNV and CHIKV were very high indicating probable re-infection. Our results indicate previously undetected circulation of arboviruses in Cameroon, and suggest that they are important, overlooked public health problems.

  4. Silicate volcanism on Io

    Science.gov (United States)

    Carr, M. H.

    1986-03-01

    This paper is mainly concerned with the nature of volcanic eruptions on Io, taking into account questions regarding the presence of silicates or sulfur as principal component. Attention is given to the generation of silicate magma, the viscous dissipation in the melt zone, thermal anomalies at eruption sites, and Ionian volcanism. According to the information available about Io, it appears that its volcanism and hence its surface materials are dominantly silicic. Several percent of volatile materials such as sulfur, but also including sodium- and potassium-rich materials, may also be present. The volatile materials at the surface are continually vaporized and melted as a result of the high rates of silicate volcanism.

  5. 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…

  6. African Urban Harvest: Agriculture in the Cities of Cameroon, Kenya ...

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

    2010-01-01

    . Book cover African Urban Harvest: Agriculture in the Cities of Cameroon, Kenya and Uganda. Editor(s):. Gordon Prain, Nancy Karanja, and Diana Lee-Smith. Publisher(s):. Springer, CIP, IDRC. January 1, 2010. ISBN: 9781441969620.

  7. The role of the Association of Cameroon Accountants as a ...

    African Journals Online (AJOL)

    ONECCA); as a regulatory body for the accounting profession in Cameroon. The data collected have been used to carefully assess the effectiveness of the accounting institution, as a regulatory body. The data reveals the extent to which effective ...

  8. Studying the Logone floodplain, Cameroon, as a coupled human ...

    African Journals Online (AJOL)

    Studying the Logone floodplain, Cameroon, as a coupled human and natural system. M Moritz, S Laborde, SC Phang, M Ahmadou, M Durand, A Fernandez, IM Hamilton, S Kari, B Mark, P Scholte, N Xiao, R Ziebe ...

  9. Evaluating the fate of organic compounds in the Cameroon ...

    African Journals Online (AJOL)

    ISHIOMA

    environment, quantify intermedia transfer processes and the major loss mechanisms from the ... Key words: Fate model, fugacity, exposure assessment, chemical fate in Cameroon, persistence. INTRODUCTION. The use of chemicals and chemical derivatives in agriculture, industry and infrastructure development has.

  10. 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.......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....

  11. 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.

  12. 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.

  13. 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...

  14. Languages of volcanic landscapes

    Science.gov (United States)

    Frederick J. Swanson

    2008-01-01

    As a young geologist in 1980, I felt a powerful attraction to volcanoes, and I thought I knew volcanoes rather well. I had studied volcanology. I had climbed volcanic peaks in the Cascades. And I had tried to be an attentive citizen of my volcanic region, the Pacific Northwest. But when I had a chance to go with other scientists to Mount St. Helens within days of its...

  15. Under five malnutrition crises in the Boko Haram Area of Cameroon ...

    African Journals Online (AJOL)

    Boko-Haram has increased their attacks along the Cameroon boarder in the Far North region of Cameroon since 2013. The prevalence of malnutrition in the north of Cameroon is high. Regions like the Adamawa, North and Far North regions have a prevalence of malnutrition of 5.2%, 6.7%, 9.0%, respectively; and, ...

  16. Deficiencies in pastoral care with prisoners in Cameroon

    Directory of Open Access Journals (Sweden)

    Abraham K. Akih

    2012-08-01

    Full Text Available Cameroon celebrated fifty years of independence from colonial rule on 20 May 2010. Major problems facing the nation are economic, social and political crises and the appalling condition of its prisons. This article focuses on pastoral care with prisoners in Cameroon. Most churches in Cameroon have no pastoral care programme for prisoners. The churches in general are not yet committed to this kind of work. The article argues that changes and reform of the penitential system will be difficult if not impossible without collaboration with other institutions and resources, which include the different faith communities and faith based organisations. The focus should be on the care and well-being of those within its walls if successful rehabilitation is to take place. Spiritual care will contribute to the general well-being of prisoners. The article gives a broad overview of the situation of prisons and prisoners in Cameroon and presents a pastoral care approach that could contribute to the overall improvement of the lives of people in Cameroon prisons.

  17. 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

  18. Volcanism in Eastern Africa

    Science.gov (United States)

    Cauthen, Clay; Coombs, Cassandra R.

    1996-01-01

    In 1891, the Virunga Mountains of Eastern Zaire were first acknowledged as volcanoes, and since then, the Virunga Mountain chain has demonstrated its potentially violent volcanic nature. The Virunga Mountains lie across the Eastern African Rift in an E-W direction located north of Lake Kivu. Mt. Nyamuragira and Mt. Nyiragongo present the most hazard of the eight mountains making up Virunga volcanic field, with the most recent activity during the 1970-90's. In 1977, after almost eighty years of moderate activity and periods of quiescence, Mt. Nyamuragira became highly active with lava flows that extruded from fissures on flanks circumscribing the volcano. The flows destroyed vast areas of vegetation and Zairian National Park areas, but no casualties were reported. Mt. Nyiragongo exhibited the same type volcanic activity, in association with regional tectonics that effected Mt. Nyamuragira, with variations of lava lake levels, lava fountains, and lava flows that resided in Lake Kivu. Mt. Nyiragongo, recently named a Decade volcano, presents both a direct and an indirect hazard to the inhabitants and properties located near the volcano. The Virunga volcanoes pose four major threats: volcanic eruptions, lava flows, toxic gas emission (CH4 and CO2), and earthquakes. Thus, the volcanoes of the Eastern African volcanic field emanate harm to the surrounding area by the forecast of volcanic eruptions. During the JSC Summer Fellowship program, we will acquire and collate remote sensing, photographic (Space Shuttle images), topographic and field data. In addition, maps of the extent and morphology(ies) of the features will be constructed using digital image information. The database generated will serve to create a Geographic Information System for easy access of information of the Eastem African volcanic field. The analysis of volcanism in Eastern Africa will permit a comparison for those areas from which we have field data. Results from this summer's work will permit

  19. The North South Paleozoic to Quaternary trend of alkaline magmatism from Niger Nigeria to Cameroon: Complex interaction between hotspots and Precambrian faults

    Science.gov (United States)

    Ngako, Vincent; Njonfang, Emmanuel; Aka, Festus Tongwa; Affaton, Pascal; Nnange, Joseph Metuk

    2006-07-01

    The alkaline magmatism from Niger-Nigeria to Cameroon forms large scale magmatic provinces across the African plate. It displays a N-S trend from Aïr in Niger to Jos Plateau in Nigeria changing southeastwards towards Cameroon. We have compiled recent petrological, geochemical and structural data on these magmatic provinces. The data show that although there is a general age decrease from one province to another (407 ± 8 Ma in Aïr to ⩽66 Ma in Cameroon), there is no age migration in any given province, except in the Nigeria province (Younger Granites) where a rough NE-SW age decrease is observed. The relationship between these different magmatic provinces that share similar geochemical data, added to the SW-NE parallel trends of Nigeria, Benue Trough and Cameroon Line, is difficult to explain in terms of a simple northward motion of the African plate over a single hotspot. In the light of recent tectonic models, we suggest complex interaction between, on the one hand, at least two mantle plumes acting in succession (including the St. Helena mantle plume) and, on the other hand, lithospheric fractures that induce oblique alignments of new magmatic complexes.

  20. 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.

  1. 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.

  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. © 2014 The Author(s). Disasters © Overseas Development Institute, 2014.

  3. Early childhood feeding practices in northern Cameroon.

    Science.gov (United States)

    Einterz, E M; Bates, M E

    1994-01-01

    Following the identification of differences in disease patterns among infants from households of different social groups (Moslem and non-Moslem) in northern Cameroon, 534 mothers and their children 0-23 months old were studied to determine early childhood feeding practices in the 2 groups. Several significant differences were revealed. Compared with non-Moslem infants, Moslems were more likely to be given animal milk instead of breast milk before the age of 3 d. On average, millet pap was introduced to Moslem babies between their 1st and 2nd months and to non-Moslem babies between their 3rd and 4th months. Moslem mothers more commonly prepared pap with oil or cow butter as an ingredient. Moslem mothers also planned to wean their children at an earlier age than non-Moslems and were less likely to report boiling their children's drinking water. Moslem mothers of infants less than 5 months old were likely to believe their breast milk was insufficient. The implications of these findings on the higher incidence of infant diarrhoea, stunting and early childhood death among Moslems are discussed.

  4. Precambrian Lunar Volcanic Protolife

    Directory of Open Access Journals (Sweden)

    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.

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

    DEFF Research Database (Denmark)

    Ackom, Emmanuel

    2014-01-01

    -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...... 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...... of agricultural residues. The study provides policy recommendations to help encourage modern bioenergy applications from residues in Cameroon....

  6. Family, obligations, and migration: The role of kinship in Cameroon

    Directory of Open Access Journals (Sweden)

    Annett Fleischer

    2007-05-01

    Full Text Available The aim of this paper is to investigate the influence of family and kin networks on the individual decision to migrate. The study is based on qualitative ethnographic data which was collected during a field research in Cameroon in spring 2005, showing the considerable impact of the extended family on the migrant's choice to leave Cameroon for Germany. Migrants do not solely move for their own achievements and purposes, but rather as significant members of their entire immediate family. The individual is part of an informal reciprocal system of exchange which is based on trust and has social consequences, and includes duties and responsibilities for both sides.

  7. Volcanic activity and climatic changes.

    Science.gov (United States)

    Bryson, R A; Goodman, B M

    1980-03-07

    Radiocarbon dates of volcanic activity suggest variations that appear to be related to climatic changes. Historical eruption records also show variations on the scale of years to centuries. These records can be combined with simple climatic models to estimate the impact of various volcanic activity levels. From this analysis it appears that climatic prediction in the range of 2 years to many decades requires broad-scale volcanic activity prediction. Statistical analysis of the volcanic record suggests that some predictability is possible.

  8. Modeling volcanic ash dispersal

    CERN Multimedia

    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...

  9. Access to land in the Anglophone regions of Cameroon: Challenges ...

    African Journals Online (AJOL)

    Cameroon is divided into two major clusters of regions- Anglophone and Francophone. This article ... Utilising existing legislations, case laws, and policy since the dawn of the colonial era, the paper sought to examine the application to land, of the laws that have exacerbated the land crises in the country. Secondary data ...

  10. Functioning and disability in recent research from Cameroon: a ...

    African Journals Online (AJOL)

    Among other common themes, knowledge and awareness was the highest reported category (22 studies), closely followed by traditional beliefs (20 studies) and financial barriers (9 studies). Conclusion: There is a small body of primary research from Cameroon on disability. The main themes related to disability are stigma, ...

  11. Measles outbreak in a poorly vaccinated region in Cameroon

    African Journals Online (AJOL)

    ebutamanya

    2015-10-20

    Oct 20, 2015 ... Abstract. 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 ...

  12. Journal of the Cameroon Academy of Sciences - Vol 5 (2005)

    African Journals Online (AJOL)

    Malaria and HIV/AIDS in Cameroon: Antenatal care attendees as a case study in management of both infections · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. PM Ndumbe, G Elonge-Fobia, J Ngu, O Bate, D Mfonfu, 39-48 ...

  13. Cameroon native goat populations' genetic diversity and maternal ...

    African Journals Online (AJOL)

    Based on the previous migratory scenarios, the Cameroon native goats may have various maternal origins, Indian, Middle East and south Mediterranean regions. The results are useful for conservation and subsequent investigations may be undertaken to broaden genetic diversity particularly for production purpose.

  14. Page 1 JOURNAL OF THE CAMEROON ACADEMY OF SCIENCES ...

    African Journals Online (AJOL)

    hypereutrophic shallow reservoir of urban zone of Cameroon (Central Africa) from November. 1996 to December 1997. ...... spas now -96 Dec 96 jan-97 Feb. 97 March 97 Apr 97. May 97. Months species in the Yaounde Municipal Lake is typically eutrophic to hypereutrophic. This confirms the conclusion of Shiel et al.

  15. Geochemistry of the Bayonplutonic Complex – Western Cameroon ...

    African Journals Online (AJOL)

    The BayonNeoproterozoic plutonic complex located in Western Cameroon intrudes gneisses of Paleo to Neo Proterozoic age. The complex is composed of gabbro, monzogabbro and monzonites frequently crosscut by trachytic and granitic veins. The primary mineral assemblages of the gabbro and monzogabbro is ...

  16. Household-level Social Capital in Cameroon and Children's Schooling

    African Journals Online (AJOL)

    This article examines household-level social capital as a determinant of children's schooling using a cross-sectional data of the 2001 Cameroon Household Survey. Reduced form demand equations of schooling for the entire sample, male and female children are estimated separately. Results indicate that parent's ...

  17. Bars to Jars: Bamboo Value Chains in Cameroon

    NARCIS (Netherlands)

    Ingram, V.J.; Tieguhong, C.

    2013-01-01

    Bamboo is a well know and versatile material, which is a common sight across Cameroon's diverse ecosystems, from dry to humid tropical and Afromontane forests. Its numerous uses range from storage jars to decorating restaurant-bars, beehives to knives, fences, fodder, and fuel. Responding to the

  18. Bars to jars: bamboo value chains in Cameroon

    NARCIS (Netherlands)

    Ingram, V.; Tieguhong, J.C.

    2013-01-01

    Bamboo is a well know and versatile material, which is a common sight across Cameroon's diverse ecosystems, from dry to humid tropical and Afromontane forests. Its numerous uses range from storage jars to decorating restaurant-bars, beehives to knives, fences, fodder, and fuel. Responding to the

  19. Quality control in foods | Mbofung | Journal of the Cameroon ...

    African Journals Online (AJOL)

    No Abstract. Keywords: food quality; safety; GMO; control system; nutrition. Journal of the Cameroon Academy of Sciences Vol. 6 (1) 2006: pp 53-62. Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT · AJOL African Journals Online. HOW TO USE AJOL.

  20. Genetic diversity of Cameroon native goat populations revealed by ...

    African Journals Online (AJOL)

    A total of seventeen caprine microsatellite markers were used on 169 goats to investigate genetic diversity of eight Cameroon native goats and to assess genetic differentiation with the east African small goat. All microsatellites showed a high polymorphic content (PIC) of more than 0.5 in almost all ecotypes.

  1. Dentofacial injuries in commercial motorcycle accidents in Cameroon

    African Journals Online (AJOL)

    Department of Dentistry Faculte des sciences de la Sante, Université des Montagnes BP 208, Bangangté ... Faculty of dentistry. Universite des Montagnes. B P. 208 bagante- Cameroon. Email:agborasm@yahoo.com increased utilization of motorcycle transportation is ..... Pattern of paediatric maxillofacial fractures in La-.

  2. 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

  3. Anglophone Cameroon literature 1959–90: A brief overview

    African Journals Online (AJOL)

    2016-03-28

    Mar 28, 2016 ... is a representation of the conflicts and tensions resulting from changes introduced by colonial rule and a new Christian world view. When Sankie Maimo published I am Vindicated in 1959 in Ikenne, Nigeria, he must not have been aware that he was launching modern Anglophone Cameroon literature.

  4. Parental Literacy and Child Health Production in Cameroon | Baye ...

    African Journals Online (AJOL)

    This study examined the empirical impact of parental education on child health. Using Cameroon household consumption survey data collected by the government statistics office in 2001 and a range of econometric methods, the existence of prominent spillover effects linking parental literacy to better child health ...

  5. Water supply, sanitation and health risks in Yaounde, Cameroon ...

    African Journals Online (AJOL)

    Population growth and rapid urbanization in Cameroon have led to major demographic changes in the urban centres, potentially resulting in serious environmental problems in the most populated cities such as Yaounde. In order to better understand the impacts on the hygiene conditions in certain quarters of this political ...

  6. Analysis of Cameroon newspaper coverage of cross border conflicts

    African Journals Online (AJOL)

    journalism'. It is evident from the data on Table 4 that Cameroon Tribune and The Post Newspapers were incapable of having pictures of actual events from the conflict sites. Based on evidence from international news reports, conflict stories are best accompanied by conflict pictures and not pictures of personalities far from ...

  7. Francophone Cameroon literature: A conversation with Ambroise Kom

    African Journals Online (AJOL)

    2016-03-28

    Mar 28, 2016 ... about the evolution of Francophone Cameroon literature with the aim of providing a framework ... training as a postcolonial student concerned with the evolution of African countries,. I kept thinking that my place ..... (organic intellectuals of the system).4 These intellectuals were there to be the mouthpiece of ...

  8. Cameroon Journal of Agricultural Science - Vol 3, No 1 (2007)

    African Journals Online (AJOL)

    Effect of harvesting techniques on cumulative yields of huckleberry (Solanum scabrum) in the humid forest region of Cameroon · EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. M Messia, S Zok, E.E Ehabe, C Poubom. http://dx.doi.org/10.4314/cjas.v3i1.48360 ...

  9. The Status of Genetically Modified Organisms (GMO) in Cameroon ...

    African Journals Online (AJOL)

    2012-12-21

    Dec 21, 2012 ... The Status of Genetically Modified Organisms (GMO) in Cameroon-A mini. Review. 1. Introduction. One of the main applications of ... harmful to human health and the environment. The United States, followed by countries like. Brazil .... and release of GMOs. The EU and Green Peace experts participated in ...

  10. Linguistic inequality in Cameroon: The case of advertising in Douala ...

    African Journals Online (AJOL)

    Despite the vast research conducted on linguistic hegemony, linguistic inequality, multilingualism and multiculturalism in Cameroon, very little has been done in advertising as it reflects language representation. Much of the research has focused on the linguistic hegemony and privileging of French and English in ...

  11. Factors associated to bed net use in Cameroon: a retrospective ...

    African Journals Online (AJOL)

    Introduction: Insecticide treated net remains a tool of choice for malaria prevention in Cameroon. However, data suggests that its use by the population, especially vulnerable groups remains low. Moreover, there is a paucity of information about factors influencing its use. We sought out to identify factors associated with net ...

  12. Evaluating the incidence of indirect tax reforms in Cameroon ...

    African Journals Online (AJOL)

    Between 1983 and 1996, income inequality moved from 0.49 to 0.44 and subsequently to 0.41 in 2001. The indirect tax structure has a role to play in inequality reduction policies. Using the 1983/84, 1996 and the 2001 Cameroon household surveys, this study reveals that the indirect tax reforms of 1994 and 1999 have been ...

  13. Dentofacial injuries in commercial motorcycle accidents in Cameroon

    African Journals Online (AJOL)

    Dentofacial injuries in commercial motorcycle accidents in Cameroon: Pattern and cost implication of care. ... Soft tissue injuries were most frequent (91.2%) followed by trauma to the teeth (83.5%), of which 62.3% were tooth loss. Mandibular fracture was commoner than maxillary fracture; (45% versus 25.3%). A total of ...

  14. Juvenile justice in cameroon 50 years after independence ; what ...

    African Journals Online (AJOL)

    AZERTY

    eighty-seven sections covering every aspect of criminal procedure in Anglophone Cameroon. 4. The Nigerian .... adopted the Common Law rule that the criminal responsibility of a child between 10. 11. Dambazau ..... protection, education and vocational skills, with a view to assisting them to assume socially constructive ...

  15. Anglophone university students and Anglophone nationalist struggles in Cameroon

    NARCIS (Netherlands)

    Konings, P.J.J.; Abbink J., van Kessel, W.M.J.

    2005-01-01

    The importance of student politics in Africa during economic and political liberalization cannot be underestimated. However, this study of anglophone students in Cameroon cautions against treating students as a homogeneous group. It shows that although anglophone students today feel even more

  16. Youth Subjectivities and Associational Life in Bamenda, Cameroon

    African Journals Online (AJOL)

    chifaou.amzat

    2009-05-13

    May 13, 2009 ... of structural dependency), social adulthood, citizenship and social participa- tion. This study answers the above questions by focusing on the subjectivities and activities of three associations of young men and women in Bamenda,. Cameroon's leading Anglophone city. The associations include the Chosen.

  17. Muslim Rulers, Justice and Politics In Cameroon During French ...

    African Journals Online (AJOL)

    Muslim Rulers, Justice and Politics In Cameroon During French Colonialism. ... Journal for Islamic Studies ... Laamibee and Sultans certainly continued to perfom some of their former judicial duties, but they became auxiliaries of the State administrative structure and were under the control of the secular political system.

  18. Opposition Politics and Electoral Democracy in Cameroon, 1992-2007

    African Journals Online (AJOL)

    This article seeks to assess the impact of electoral democracy in Cameroon especially in terms of the performance of the Opposition between 1992 and 2007, evaluate the internal shortcomings of opposition parties, and make a projection regarding a vibrant democratic space that will go beyond routine elections to speak to ...

  19. Genetic diversity in cocoa germplasm of southern Cameroon ...

    African Journals Online (AJOL)

    The range of polymorphism of about 194 cocoa accessions collected in farms in Southern Cameroon during field surveys and 71 Trinitario and Upper Amazon clones available in genebanks on-station was assessed using 13 SSR markers. The gene diversity, genetic differentiation and genetic similarities were analysed for ...

  20. Human lorries: carriers in the British Southern Cameroon's economy ...

    African Journals Online (AJOL)

    Like her predecessor, Germany, one of the first challenges she faced was how to improve and speed up the transportation of private and public goods in a ... This essay aims at understanding the logic of these changes and the implications of these regulations in modern day Northwest and Southwest regions of Cameroon.

  1. Local vegetables in Cameroon: Corchorus species used as a vegetable.

    NARCIS (Netherlands)

    Westphal-Stevels, J.M.C.

    1986-01-01

    An agro-botanical study of local vegetables in Cameroon is in preparation, including the taxonomy, identity, morphology, agronomy and nutritional value of about 70 species. Corchorus olitorius L. and other edible species of the genus Corchorus L. (Tiliaceae) are part of this study. The wide

  2. The Numba ductile deformation zone (northwest Cameroon): A ...

    Indian Academy of Sciences (India)

    and (ii) a dextral sense of shear motion. Conic section method reveals two dominant ... (CCSZ) and associated syn-kinematic intrusions and (ii) into the tectonic model of Pan-African belt of central Africa in Cameroon. 1. Introduction ... undeformed stage, to the final fold are a matter of significance to kinematic studies of fold-.

  3. The present status and perspectives of Biotechnology in Cameroon ...

    African Journals Online (AJOL)

    The present status and perspectives of Biotechnology in Cameroon with particular reference to GM and non-GM technologies. ... The present article reviews these achievements, and further describes the applications of biotechnology techniques to health, plant and animal production including the recent introduction of Bt- ...

  4. Smoke-Free Worksites and Public Spaces in Cameroon | IDRC ...

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

    It is also a way to help smokers quit. The research team will evaluate the application of regulations forbidding the consumption and sale of tobacco in public spaces in the city, strengthen the capacity of those involved in their application, and promote public support for smoke-free public spaces in Cameroon.

  5. The mount Cameroon height determined from ground gravity data ...

    African Journals Online (AJOL)

    ... in mountainous areas, where the topography is very rough. Mount Cameroon, which is the highest summit in central and western Africa, is now known to culminate at 4037.7 ± 0.7 m above sea level. This height is nearly 60 m less than the approximate value of 4095 m published by the National Institute of Cartography.

  6. The socio-cultural implications of climate change in Cameroon ...

    African Journals Online (AJOL)

    Climate change impact has remained a serious threat to man and more particularly in the water-stressed environment of north Cameroon where in most cases, man struggles for bare survival by eking out a living from a harsh or hostile climatic environment. In this region, the socio-cultural impacts can be devastating as has ...

  7. Risk factors of cervical intraepithelial lesion in Douala-Cameroon ...

    African Journals Online (AJOL)

    Risk factors of cervical intraepithelial lesion in Douala-Cameroon: Implications of Herpes Simplex Virus Type 2, Chlamydia Trachomatis and Treponema Pallidum. ... Infection with high risk oncogenic human papillomavirus (HPV) such as HPVs 16 and 18 is the main cause of cervical cancer. ... a description of the source ...

  8. Determining the Optimum Level of Working Capital in the Cameroon ...

    African Journals Online (AJOL)

    The issue of working capital is very important to the operations of the Cameroon Development Corporation (CDC) Net working capital (i.e. the excess of liquid current assets over current liabilities) is an indispensable component of any business organization's capital structure. For any company to make profit in order to ...

  9. Care for Older Persons in Cameroon: Alternatives for Social ...

    African Journals Online (AJOL)

    Despite its relevance to social development, providing apposite and effective care services to elderly men and women is still a major challenge in contemporary Cameroon. This is largely due to the weak institutional support system and poverty which estranges the elderly and jeopardizes their well-being. Deconstructing the ...

  10. Salt, history and culture in the western grasslands of Cameroon ...

    African Journals Online (AJOL)

    This paper examines the socio-cultural value of salt among the people of the western grasslands of Cameroon from the precolonial era to contemporary times. Salt was andremains an important condiment used in households, marriages, treatment of the sick, initiation and other cultural ceremonies throughout the western ...

  11. Backprojection of volcanic tremor

    Science.gov (United States)

    Haney, Matthew M.

    2014-01-01

    Backprojection has become a powerful tool for imaging the rupture process of global earthquakes. We demonstrate the ability of backprojection to illuminate and track volcanic sources as well. We apply the method to the seismic network from Okmok Volcano, Alaska, at the time of an escalation in tremor during the 2008 eruption. Although we are able to focus the wavefield close to the location of the active cone, the network array response lacks sufficient resolution to reveal kilometer-scale changes in tremor location. By deconvolving the response in successive backprojection images, we enhance resolution and find that the tremor source moved toward an intracaldera lake prior to its escalation. The increased tremor therefore resulted from magma-water interaction, in agreement with the overall phreatomagmatic character of the eruption. Imaging of eruption tremor shows that time reversal methods, such as backprojection, can provide new insights into the temporal evolution of volcanic sources.

  12. Volcanic eruptions on Io

    Science.gov (United States)

    Strom, R. G.; Schneider, N. M.; Terrile, R. J.; Cook, A. F.; Hansen, C.

    1981-09-01

    Nine eruption plumes which were observed during the Voyager 1 encounter with Io are discussed. During the Voyager 2 encounter, four months later, eight of the eruptions were still active although the largest became inactive sometime between the two encounters. Plumes range in height from 60 to over 300 km with corresponding ejection velocities of 0.5 to 1.0 km/s and plume sources are located on several plains and consist of fissures or calderas. The shape and brightness distribution together with the pattern of the surface deposition on a plume 3 is simulated by a ballistic model with a constant ejection velocity of 0.5 km/s and ejection angles which vary from 0-55 deg. The distribution of active and recent eruptions is concentrated in the equatorial regions and indicates that volcanic activity is more frequent and intense in the equatorial regions than in the polar regions. Due to the geologic setting of certain plume sources and large reservoirs of volatiles required for the active eruptions, it is concluded that sulfur volcanism rather than silicate volcanism is the most likely driving mechanism for the eruption plumes.

  13. Holocene Volcanic Records in the Siple Dome Ice Cores

    Science.gov (United States)

    Zielinski, G. A.; Dunbar, N. W.; Kurbatov, A. V.; Voisin, D. T.

    2001-12-01

    Using both the SO42- and Cl- time series and tephrochronological analyses, a highly detailed record of Holocene volcanism is being reconstructed from the Siple Dome A ice core. The volcanic glaciochemical record is being developed at a 2-4 year resolution for the last 10,000 years. Volcanic peaks were identified as those having a concentration of 2{σ } above the mean positive residual of the spline fit, as was done for the GISP2 volcanic record. We identified about 70 volcanic events for the mid-late Holocene. The largest sulfate signal (350 ppb) over the time period evaluated occurs at 2242 years ago. Large signals of volcanically enhanced sulfate in the ice core record also occur around 720 years ago (1280 C.E.;194-249 ppb)and 4710 years ago (378ppb). Ages for large equatorial or southern hemisphere volcanic eruptions are synchronous with identified sulfate peaks in the reconstructed volcanic record. However, the continuous scan for volcanic glass in these same samples yielded glass compositions more in-line with Antarctica volcanic zones (i.e., local eruptions). Nevertheless, our record provides important information on the atmospheric impact of volcanism in Antarctica geochemical cycles. The glass (i.e., tephra) found in various samples indicate that volcanoes within the McMurdo Volcanic Center (Victoria Land and the islands off its coast) including Mt. Melbourne, The Pleaides and Buckle Island appear to be the most active in Antarctica during the late Holocene. Rhyolitic shards of a composition not found in Antarctica also are present in some layers, although they are not overly abundant. The presence of dust with a Patagonian origin in East Antarctica ice cores as well as the nature of the Antarctica vortex indicate that material from this part of the southern hemisphere can reach various parts of Antarctica. Common circulation patterns around the Ross and Amundson Seas as well as the satellite trace of aerosols from the 1991 Cerro Hudson eruption, Argentina

  14. Prevention of Catastrophic Volcanic Eruptions

    OpenAIRE

    Fujii, Yoshiaki; Kodama, Jun-ichi; Fukuda, Daisuke; Dassanayake, Abn

    2017-01-01

    Giant volcanic eruptions emit sulphate aerosols as well as volcanic ash. Needless to say that volcanic ash causes significant damage to the environment and human at large. However, the aerosols are even worse. They reach the Stratosphere and stay there for months to years reflecting insolation. As a result, air temperature at the Earth's surfaces drops. Even a slight temperature drop may cause severe food shortage. Yellowstone supervolcano, for example, can even make human in the Northern Hem...

  15. 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

  16. 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...

  17. A permanent volcanic hazard hiding in diffuse degassing areas

    Science.gov (United States)

    Viveiros, Fátima; Silva, Catarina; Ferreira, Teresa; Pacheco, Joana; Luís Gaspar, João

    2017-04-01

    Carbon dioxide (CO2) is one of the most abundant volcanic gases and it is released not only during eruptive events, but also during periods of quiescence through fumaroles, springs and soil diffuse degassing areas. In this last case, CO2 is permanently and silently released from the soils and high CO2 concentrations can be measured if the gas accumulates in depressed and non-ventilated areas (such as caves, pits), or even if it enters in buildings. From a public health perspective CO2 is considered an inert asphyxiant gas and may be lethal when present in concentrations higher than 10 vol.%. In the last 30 years several diffuse degassing areas have been identified in different volcanic systems and lethal incidents due to high CO2 concentrations were reported in volcanic environments of Italy (Alban Hills), New Zealand (Rotorua), Cameroon (Lake Nyos and Lake Cameroon), USA (Mammoth Mountain) and Portugal (Azores archipelago). In the Azores volcanic archipelago several villages are located in diffuse degassing areas, where lethal indoor CO2 concentrations (> 20 vol.%) were measured. Recent studies showed that the rate of CO2 emission may change not only during seismo-volcanic unrest, but also due to changes in the meteorological conditions (e.g. barometric pressure, rainfall, wind speed). Few works are available in the literature with permanent monitoring of indoor CO2 in diffuse degassing environments and the monitoring tests are usually applied during a short period of time. This study shows the results of four years (2012-2016) of permanent CO2 monitoring in 12 buildings placed at Caldeiras da Ribeira Grande, an area located in the north flank of Fogo Volcano (São Miguel Island, Azores archipelago), where thermal anomalies and CO2 emissions were detected. CO2 fluxes as high as 20000 g m-2 d-1 are released from the soils and temperature in some sites reaches 100°C. Spike-like and long term variations are observed in the time series recorded by a total of 52

  18. Bars to jars: bamboo value chains in Cameroon.

    Science.gov (United States)

    Ingram, Verina; Tieguhong, Julius Chupezi

    2013-04-01

    Bamboo is a well know and versatile material, which is a common sight across Cameroon's diverse ecosystems, from dry to humid tropical and Afromontane forests. Its numerous uses range from storage jars to decorating restaurant-bars, beehives to knives, fences, fodder, and fuel. Responding to the paucity of data on species and uses, the value chain for bamboo in Cameroon was analyzed. Based on 171 interviews and field observations, two African indigenous species (alpine Yushania alpina and savannah Oxytenanthera abyssinica) and exotic (Bambusa vulgaris spp.) bamboos were identified as most utilized. They were tracked from major production zones to final consumers. The ecological, socio-economic, institutional, and governance contexts and impacts are described and analyzed. Issues for research, conservation, and development are highlighted. These include the ambiguous regulatory status, the relationship between tenure and management, threats and conservation of African species and options to increase the sustainable livelihoods for stakeholders dependent upon bamboo.

  19. Teachers’ approaches to language classroom assessment in Cameroon primary schools

    Directory of Open Access Journals (Sweden)

    Achu Charles Tante

    2013-10-01

    Full Text Available Assessment has a huge impact on ESL primary pupils, in part, because on the curriculum English is both a subject and also a language of learning all the other subjects. For children still acquiring L1 it is daunting sometimes to be expected to understand concepts in L2. It may be difficult then to gather information to make an impartial judgement with regards to a pupil’s language level. This study is a preliminary inquiry that attempts to find out teachers’ approaches to classroom assessment in Cameroon primary schools. Using a qualitative open-ended question the researcher finds out three main categories of assessment approaches used by teachers. From the categories extrapolations on possible assumptions that guide teachers’ choices of assessment procedures are described and suggested for future study. Keywords Classroom assessment approach, Cameroon, scheme of work, ESL/EFL, Young Learners 

  20. Waste management in Cameroon. A new policy perspective?

    Energy Technology Data Exchange (ETDEWEB)

    Manga, Veronica Ebot [Department of Geology and Environmental Science, University of Buea, P.O. Box 63, Buea (Cameroon); Forton, Osric Tening [Waste and Energy Research Group (WERG), Faculty of Science and Engineering, University of Brighton, Brighton, BN2 4GJ (United Kingdom); Ramboll Whitbybird, 60 Newman Street, London, W1T 3DA (United Kingdom); Read, Adam D. [Hyder Consulting Ltd., Aston Cross Business Village, 50 Rocky Lane, Aston, Birmingham, B6 5RQ (United Kingdom)

    2008-02-15

    Towns and cities in Cameroon exhibit the burdens of waste management which characterise so many African cities. Several factors including inadequate financial resources, low levels of enforcement of regulations and poor governance often lead to poor solid waste management services. This paper presents a critical analysis of the state of solid waste management regulations in Cameroon and constraints this places on the delivery of sustainable waste management solutions. A case study of the Limbe Municipal Council is used to highlight some of the waste management related problems in the country. Results indicate that solid waste management services are rudimentary; essentially collect and dump. Current regulations do not adequately address waste handling or disposal. There are inefficiencies in the implementation of waste management policy due to the devolved responsibilities between several governmental agencies and the local councils. The paper discusses some of these constraints and concludes with suggestions for improving the delivery of sustainable waste management solutions. (author)

  1. Prevalence and causes of hearing impairment in Fundong Health District, North-West Cameroon.

    Science.gov (United States)

    Ferrite, Silvia; Mactaggart, Islay; Kuper, Hannah; Oye, Joseph; Polack, Sarah

    2017-04-01

    To estimate the prevalence and causes of hearing impairment in Fundong Health District, North-West Cameroon. We selected 51 clusters of 80 people (all ages) through probability proportionate to size sampling. Initial hearing screening was undertaken through an otoacoustic emission (OAE) test. Participants aged 4+ years who failed this test in both ears or for whom an OAE reading could not be taken underwent a manual pure-tone audiometry (PTA) screening. Cases of hearing impairment were defined as those with pure-tone average ≥41 dBHL in adults and ≥35 dBHL in children in the better ear, or children under age 4 who failed the OAE test in both ears. Each case with hearing loss was examined by an ear, nose and throat nurse who indicated the main likely cause. We examined 3567 (86.9%) of 4104 eligible people. The overall prevalence of hearing impairment was 3.6% (95% confidence interval [CI]: 2.8-4.6). The prevalence was low in people aged 0-17 (1.1%, 0.7-1.8%) and 18-49 (1.1%, 0.5-2.6%) and then rose sharply in people aged 50+ (14.8%, 11.7-19.1%). Among cases, the majority were classified as moderate (76%), followed by severe (15%) and profound (9%). More than one-third of cases of hearing impairment were classified as unknown (37%) or conductive (37%) causes, while sensorineural causes were less common (26%). Prevalence of hearing impairment in North-West Cameroon is in line with the WHO estimate for sub-Saharan Africa. The majority of cases with known causes are treatable, with impacted wax playing a major role. © 2017 John Wiley & Sons Ltd.

  2. Media reporting of tenofovir trials in Cambodia and Cameroon

    Directory of Open Access Journals (Sweden)

    Wong Elaine

    2005-08-01

    Full Text Available Abstract Background Two planned trials of pre-exposure prophylaxis tenofovir in Cambodia and Cameroon to prevent HIV infection in high-risk populations were closed due to activist pressure on host country governments. The international news media contributed substantially as the primary source of knowledge transfer regarding the trials. We aimed to characterize the nature of reporting, specifically focusing on the issues identified by media reports regarding each trial. Methods With the aid of an information specialist, we searched 3 electronic media databases, 5 electronic medical databases and extensively searched the Internet. In addition we contacted stakeholder groups. We included media reports addressing the trial closures, the reasons for the trial closures, and who was interviewed. We extracted data using content analysis independently, in duplicate. Results We included 24 reports on the Cambodian trial closure and 13 reports on the Cameroon trial closure. One academic news account incorrectly reported that it was an HIV vaccine trial that closed early. The primary reasons cited for the Cambodian trial closure were: a lack of medical insurance for trial related injuries (71%; human rights considerations (71%; study protocol concerns (46%; general suspicions regarding trial location (37% and inadequate prevention counseling (29%. The primary reasons cited for the Cameroon trial closure were: inadequate access to care for seroconverters (69%; participants not sufficiently informed of risks (69%; inadequate number of staff (46%; participants being exploited (46% and an unethical study design (38%. Only 3/23 (13% reports acknowledged interviewing research personnel regarding the Cambodian trial, while 4/13 (30.8% reports interviewed researchers involved in the Cameroon trial. Conclusion Our review indicates that the issues addressed and validity of the media reports of these trials is highly variable. Given the potential impact of the media

  3. Epilepsy and cysticercosis in Northwest Cameroon: a serological study.

    Science.gov (United States)

    Elliott, Irene; Jerome, Ambanibe; Angwafor, Samuel A; Smith, Mary Lou; Takougang, Innocent; Noh, John; Tsang, Victor; Wilkins, Patricia; Cockburn, Lynn; Keystone, Jay; Njamnshi, Alfred K; Snead, O Carter

    2013-05-01

    The prevalence of epilepsy in Cameroon is higher than that of the industrialized world and other developing countries. Neurocysticercosis due to Taenia solium infestation has been reported as a major cause of epilepsy in some parts of Cameroon although there are some conflicting data. The prevalence of epilepsy is especially high in the Momo division of the North-West Province of Cameroon. We hypothesized that individuals with epilepsy in this region have a higher percentage of seropositivity to T. solium than matched controls. We conducted a case-control study in the Momo subdivision of Ngie. Individuals with epilepsy were recruited from the health centers in Ngie. Control subjects were selected from 19 Ngie villages. Potential cases of people with epilepsy (PWE) were identified through a questionnaire applied by trained field workers, using history of epileptic seizures as a key indicator. Blood samples were taken from all consenting individuals by finger prick, stored in StabilZyme Select, and assayed for antibodies to T. solium in an Atlanta based reference laboratory. We accrued 249 patients with epilepsy, of whom 237 met the inclusion criteria, and 245 age-matched controls. There was no significant difference in seropositivity to T. solium between those individuals with epilepsy (5%) and controls (4.9%). Our data do not support the hypothesis that epilepsy is associated with seropositivity to T. solium. It is highly unlikely that cysticercosis plays a causative role in the high prevalence of epilepsy in this region of Cameroon. Copyright © 2013 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.

  4. The role of parents in early childhood education in Cameroon

    OpenAIRE

    Ashu, F. (Felix)

    2013-01-01

    This research aims to provide some suggestions for the role of parents in early childhood education in Cameroon. It also tries to create an awareness of the current state of educational structures and institutions that are available for early childhood education and to identify gaps where urgent attention is needed. Data for this study was collected through interview with the use of Skype. A stratified random sampling method was used and the focus groups were parents who live both in cities a...

  5. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  7. Association between intimate partner violence and induced abortion in Cameroon.

    Science.gov (United States)

    Alio, Amina P; Salihu, Hamisu M; Nana, Philip N; Clayton, Heather B; Mbah, Alfred K; Marty, Phillip J

    2011-02-01

    To examine the association between intimate partner violence (IPV; physical, sexual, and emotional violence) and induced abortion in Cameroon. We used data from the 2004 Cameroon Demographic Health Survey (DHS) and hierarchic multivariate modeling to compare the rates of induced abortion by IPV type. In 2004, 2570 women were administered the domestic violence module of the DHS. Of those women, 126 (4.9%) reported having had at least 1 induced abortion. Cameroonian women reported high rates of IPV: physical violence (995 [38.7%]); emotional violence (789 [30.7%]); and sexual violence (381 [14.8%]). After adjusting for covariates, physical and sexual IPV increased the risk for induced abortion, whereas the association between emotional violence and induced abortion was not significant in multivariate models. Given the increased risk for maternal morbidity and mortality following unsafe induced abortions in Cameroon, the association between induced abortion and IPV is of interest in terms of public health. Programs targeted at preventing IPV might reduce the rate of maternal morbidity and mortality. Copyright © 2010 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.

  8. Dinosaur trackways from the early Late Cretaceous of western Cameroon

    Science.gov (United States)

    Martin, Jeremy E.; Menkem, Elie Fosso; Djomeni, Adrien; Fowe, Paul Gustave; Ntamak-Nida, Marie-Joseph

    2017-10-01

    Dinosaur trackways have rarely been reported in Cretaceous strata across the African continent. To the exception of ichnological occurrences in Morocco, Tunisia, Niger and Cameroon, our knowledge on the composition of Cretaceous dinosaur faunas mostly relies on skeletal evidence. For the first time, we document several dinosaur trackways from the Cretaceous of the Mamfe Basin in western Cameroon. Small and medium-size tridactyl footprints as well as numerous large circular footprints are present on a single horizon showing mudcracks and ripple marks. The age of the locality is considered Cenomanian-Turonian and if confirmed, this ichnological assemblage could be younger than the dinosaur footprints reported from northern Cameroon, and coeval with or younger than skeletal remains reported from the Saharan region. These trackways were left in an adjacent subsiding basin along the southern shore of the Benue Trough during a time of high-sea stand when the Trans-Saharan Seaway was already disconnecting West Africa from the rest of the continent. We predict that other similar track sites may be occurring along the margin of the Benue Trough and may eventually permit to test hypotheses related to provincialism among African dinosaur faunas.

  9. 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. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  10. The Impact Of Dental Auxiliaries In Oral Health Delivery In Cameroon

    African Journals Online (AJOL)

    Objective: To assess the impact of dental auxiliaries in oral health delivery in Cameroon. Materials and Methods: A cross-sectional study of 47 dental auxiliaries recruited from six of 10 provinces in Cameroon was conducted in 2010. A self-administered questionnaire elicited information on demography, training received ...

  11. HIV/AIDS in Cameroon: Rising gender issues in policy-making matters

    African Journals Online (AJOL)

    This literature review investigated gender differentials in HIV/AIDS in Cameroon and to which extent gender was taken into account in the country's current policy on. HIV/AIDS. The review found that in Cameroon women were at increased risk of being infected with HIV/AIDS compared to men and that apart from biological ...

  12. Under Five Malnutrition Crises in the Boko Haram Area of Cameroon

    African Journals Online (AJOL)

    bUnder Privilege Children and Women Assistance (UPCAWA-SWEDEN), Researcher Cameroon Branch, Bamenda, Cameroon ... prevalence of malnutrition of 5.2%, 6.7%, 9.0%, respectively; and, in addition to that, 1289 children have been admitted for ... of civilians, destruction of property, and even kidnapping in the.

  13. 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…

  14. 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.

  15. Determination of the isostatic compensation mechanism of the ...

    African Journals Online (AJOL)

    The Adamawa dome in Central Cameroon represents a post-Cretaceous uplifted region, paralled to a Precambrian Foumban Shear Zone, and characterised by Tertiary-Recent volcanic centres of the Cameroon Volcanic Line, and a long negative Bouguer anomaly similar in shape and amplitude to those of other African ...

  16. A Study of Vowel Nasalization and Vowel Epenthesis Processes in Cameroon Francophone English

    Directory of Open Access Journals (Sweden)

    Gilbert Tagne Safotso

    2017-03-01

    Full Text Available Unlike Cameroon English and Received Pronunciation, Cameroon Francophone English has a number of nasal  and epenthetic vowels. Those nasal vowels are generally French ones, as Cameroon Francophone English is heavily influenced by that language. The epenthetic vowels found in Cameroon Francophone English as in many other non-native Englishes are difficult to explain. Part of the data analysed is drawn from past studies (Safotso 2001, 2006, 2012 & 2015; Kouega 2008. This is complemented by the oral reading of some test words by French-speaking Cameroonian undergraduate/postgraduate students and some speech gathered from debates and interventions on various national TV channels and radio stations. Results show that in Cameroon Francophone English, vowel nasalization and vowel epenthesis occur in specific positions. This paper attempts to show how they operate in that variety of English.

  17. Microstructures and magnetic fabrics of the Ngaoundéré granite pluton (Cameroon): Implications to the late-Pan-African evolution of Central Cameroon Shear Zone

    Science.gov (United States)

    Dawaï, Daouda; Tchameni, Rigobert; Bascou, Jérome; Awe Wangmene, Salomon; Fosso Tchunte, Périclex Martial; Bouchez, Jean-Luc

    2017-05-01

    The Ngaoundéré granite pluton, in Central-North Cameroon, located near the Central Cameroon Shear zone (CCSZ), and previously studied for its petrography and geochemistry, is characterized by the absence of macroscopic markers of deformation. In this study, we report microstructures and magnetic fabrics (AMS) of this pluton and discuss the relationship with the Pan-African evolution of the CCSZ. The pluton consists of a porphyritic Hbl-Bt-monzogranite at its rim and a porphyritic biotite-granite at its core, a petrographic distribution denoting a normal zoning pattern, i.e. more silicic toward the centre. As expected, magnetic susceptibilities values also exhibit a zoning pattern in agreement with petrographic zonation. Thermomagnetic data indicate that this pluton is dominantly ferromagnetic in behaviour. As indicated by its microstructures, the pluton has suffered a continuum of deformation from the magmatic state to the high temperature solid-state during magma crystallization and solidification. The magnetic foliations dominantly strike NE-SW and dip moderately to steeply and the lineations mostly plunge shallowly to the NE or SW, roughly parallel to NE-to ENE-trending Central Cameroun Shear Zone (CCSZ). The foliation poles define a girdle pattern with a zone axis (52°/11°) rather close to the best line of the lineations (44°/21°). These fabrics correlate with the structures of the country rocks ascribed by several workers to a regional transpression. Toward the margins of the pluton, particularly the northern one, the lineations tend to rotate from NE to N in azimuth. This change is interpreted as due to strain partitioning, simple shearing with NE-SW extension being relayed by compression toward the northern pluton border. This new magnetic fabric study suggests that the Ngaoundéré pluton (poorly dated at c. 575 Ma) was emplaced during the late stages of the CCSZ dextral transpressive movement. It also provides some more constraints on the correlation

  18. Late Neogene Volcanic Stratigraphy in the Southern Puertecitos Volcanic Province of Baja California: Time Constraints and Vent Source Location

    Science.gov (United States)

    Garcia-Carrillo, P.; Martin, A.; Lopez-Martinez, M.; Cañon, E.

    2007-05-01

    during the opening of the Lower Delfin basin has been accommodated to the east. Our data support multiple source vents located offshore the central Puertecitos Volcanic Province. These pyroclastic flows may constitute useful marker horizons in marine seismic lines for reconstructing the timing and amount of extension across conjugate margins in the Lower Delfin basin.

  19. Correlating geochemistry, tectonics, and volcanic volume along the Central American volcanic front

    Science.gov (United States)

    Bolge, Louise L.; Carr, Michael J.; Milidakis, Katherine I.; Lindsay, Fara N.; Feigenson, Mark D.

    2009-12-01

    The Central American volcanic front consists of several distinct volcanic lineaments or segments, separated by right steps and/or changes in strike. Each volcanic line is rotated slightly counterclockwise from the strike of the inclined seismic zone. Right stepping volcanic lines, oblique to the strike of the slab, create a sawtooth pattern in the depth to the slab. Zr/Nb is the first geochemical signature with consistent large offsets at the right steps in the volcanic front. Moreover, Zr/Nb mirrors the sawtooth variation in depth to the slab; within a segment it increases from SE to NW, and at the right steps, separating segments, it abruptly decreases. Unfortunately, there is no simple negative correlation between Zr/Nb and depth to the slab because Zr/Nb also has a regional variation, similar to previously documented regional variations in slab tracers in Central America (e.g., Ba/La, U/Th, and 87Sr/86Sr). Within a segment, Zr/Nb decreases with increasing depth to slab. This can be explained in two ways: a Nb retaining mineral, e.g., amphibole, in the subducting slab is breaking down gradually with increasing depth causing more Nb to be released and consequently a smaller Nb depletion in deeper melts; alternatively, all melts have the same initial Nb depletion which is then diluted by acquiring Nb from the surrounding mantle wedge as melts rise and react. Deeper melts have longer paths and therefore more reaction with the mantle wedge diluting the initial Nb depletion. Within each volcanic segment there is variation in eruptive volume. The largest volcanoes generally occur in the middle of the segments, and the smaller volcanoes tend to be located at the ends. Connecting the largest volcanoes in each segment suggests an axis of maximum productivity. This is likely the surface projection of the center of the melt aggregation zone. The largest volcanoes tap the entire melt zone. Those with shallow depths to the slab tap just the front part of the melt zone and

  20. [Malaria vector control in Cameroon: past, present, future. Reflections].

    Science.gov (United States)

    Carnevale, P; Mouchet, J

    2001-07-01

    During the fifties, large scale malaria vector control projects based upon house spraying were implemented in Southern and Northern parts of Cameroon in line of malaria eradication concept. In the South, the pilot zone of Yaounde gathered about 150,000 inhabitants, in the forest area. First operations started in 1953 but the programme became actually operational in 1956. It was divided in two parts: the western part was treated with DDT, while the eastern one was treated with dieldrin. At the same time, the whole forested area was also treated with dieldrin until 1960. Yaounde itself was not treated because it was free of anopheles and malaria. House spraying in the pilot area of Yaounde was a complete success and plasmodic index dropped below 1%. The same success was observed in most of the southern treated areas. Unfortunatly dieldrin resistance of An. gambiae hampered this programme which stopped in 1960. The northem pilot project dealt with some 250,000 inhabitants around Maroua, in a savanna area. To avoid dieldrin resistance observed in 1956, DDT was selected and house spraying started in 1959. From a strictly operational point of view, the campaign was considered as a success. But after two years, it was noticed that plasmodic index remained still around the same value of 35% and the programme stopped. It was thus stated that according to available techniques it was not possible to reach the ultimate goal of eradication even when chemoprophylaxis (chloroquin + pyrimethamin) was added. The comparison between south (= success) and north (= failure) was very interesting as it underlined the big differences between epidemiological faces, an unaccepted concept at that time. Now ecological and epidemiological diversity is the well acknowledged. It also underlined the need of diversity of strategies according to the epidemiology of the disease and the ecology of its vector Vector control was then stopped for a while. In the eighties, Primary Health Care was

  1. 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...

  2. Volcanology: Volcanic bipolar disorder explained

    Science.gov (United States)

    Jellinek, Mark

    2014-02-01

    Eruptions come in a range of magnitudes. Numerical simulations and laboratory experiments show that rare, giant super-eruptions and smaller, more frequent events reflect a transition in the essential driving forces for volcanism.

  3. Hygroscopic properties of volcanic ash

    National Research Council Canada - National Science Library

    T. L. Lathem; P. Kumar; A. Nenes; J. Dufek; I. N. Sokolik; M. Trail; A. Russell

    2011-01-01

      Volcanic ash is hygroscopic Water vapor adsorption is the main proceess controlling ash hygroscopicity The results can be parameterized in a simple correlation for use in models Limited observational...

  4. Monogenetic volcanic hazards and assessment

    Science.gov (United States)

    Connor, C.; Connor, L. J.; Richardson, J. A.

    2012-12-01

    Many of the Earth's major cities are build on the products of monogenetic volcanic eruptions and within geologically active basaltic volcanic fields. These cities include Mexico City (Mexico), Auckland (New Zealand), Melbourne (Australia), and Portland (USA) to name a few. Volcanic hazards in these areas are complex, and involve the potential formation of new volcanic vents and associated hazards, such as lava flows, tephra fallout, and ballistic hazards. Hazard assessment is complicated by the low recurrence rate of volcanism in most volcanic fields. We have developed a two-stage process for probabilistic modeling monogenetic volcanic hazards. The first step is an estimation of the possible locations of future eruptive vents based on kernel density estimation and recurrence rate of volcanism using Monte Carlo simulation and accounting for uncertainties in age determinations. The second step is convolution of this spatial density / recurrence rate model with hazard codes for modeling lava inundation, tephra fallout, and ballistic impacts. A methodology is presented using this two-stage approach to estimate lava flow hazard in several monogenetic volcanic fields, including at a nuclear power plant site near the Shamiram Plateau, a Quaternary volcanic field in Armenia. The location of possible future vents is determined by estimating spatial density from a distribution of 18 mapped vents using a 2-D elliptical Gaussian kernel function. The SAMSE method, a modified asymptotic mean squared error approach, uses the distribution of known eruptive vents to optimally determine a smoothing bandwidth for the Gaussian kernel function. The result is a probability map of vent density. A large random sample (N=10000) of vent locations is drawn from this probability map. For each randomly sampled vent location, a lava flow inundation model is executed. Lava flow input parameters (volume and average thickness) are determined from distributions fit to field observations of the low

  5. 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.

  6. 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.

  7. Pteridophyta collected in Northern Nigeria and Northern Cameroon

    Directory of Open Access Journals (Sweden)

    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. The condition of foreigners in the family law of Cameroon

    Directory of Open Access Journals (Sweden)

    Valeri Lesmont Bahoken

    2016-10-01

    Full Text Available The preamble of the constitution of Cameroon enshrines the principle of assimilation of foreigners into nationals through the Family law. However in concrete terms, this constitutional provision is undermined (limited, hindered by a number of political and sociological constraints. The foreigner faces limitations in enjoying the said rights as well as in creating them. It is therefore necessary to amend the Cameroonian legislation so that it complies fully with the exigencies (requirements, needs of fundamental rights, the construction of the universal human being (man in general, who will be governed by the same rules everywhere.

  9. Cameroon; Poverty Reduction Strategy Paper-Progress Report

    OpenAIRE

    International Monetary Fund

    2008-01-01

    The growth rate of agriculture in Cameroon was estimated at 3.3 percent in 2006, compared with 2.7 percent in 2005. This is owing to increased activity in the food agriculture sector (4.3 percent) and in forestry and logging (4.0 percent). Livestock farming and fisheries, on the one hand, grew by 3 percent and 2 percent, respectively. Industrial and commercial agriculture, on the other hand, experienced a slowdown, on the one hand, with a growth rate of –2.3 percent in 2006 compared with 1.7 ...

  10. Paragonimiasis in Cameroon: molecular identification, serodiagnosis and clinical manifestations.

    Science.gov (United States)

    Nkouawa, Agathe; Okamoto, Munehiro; Mabou, Alida Kouojip; Edinga, Eulodie; Yamasaki, Hiroshi; Sako, Yasuhito; Nakao, Minoru; Nakaya, Kazuhiro; Blair, David; Agatsuma, Takeshi; Enyong, Peter; Shibahara, Toshiyuki; Moyou-Somo, Roger; Ito, Akira

    2009-03-01

    Paragonimiasis is a common parasitic zoonosis in Cameroon and neighbouring countries in Western Africa. Serum, sputum and faecal samples were collected in an endemic area of South West Province, Cameroon, after administration of a questionnaire to identify individuals with appropriate symptoms and histories. Microscopic examination revealed eggs in sputum from 16 people, but none in any faecal sample. These 16 were among the 25 and 26 people, respectively, positive by ELISA and by immunoblot using Paragonimus africanus crude antigens. Copro-DNA detection was attempted using 23 faecal samples (18 from sputum egg-negative and five from sputum egg-positive individuals). Copro-DNA was detected in four of the five sputum egg-positive individuals. These results strongly suggest that: (1) serology is much more sensitive than sputum examination for diagnosis of paragonimiasis; and (2) a copro-DNA test may be more sensitive than a microscopic search for eggs in faeces. Molecular sequence data from ITS2 and cox1 genes confirmed that adult worms experimentally raised in cats were P. africanus and that eggs from sputum or other worm products from human faeces also belonged to this species. Based on these results, 26 of 168 persons (15.5%) were diagnosed as suffering from paragonimiasis.

  11. Poverty and Share Revenue in the Cameroon Cocoa Zone

    Directory of Open Access Journals (Sweden)

    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.

  12. Local governance in disaster risk reduction in Cameroon

    Directory of Open Access Journals (Sweden)

    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. RITUAL USE OF CURRENCY IN LAIMBWE HISTORY, CAMEROON

    Directory of Open Access Journals (Sweden)

    Henry Kam Kah

    2018-02-01

    Full Text Available The advent of Europeans in Cameroon in the 15th century and the introduction of a western currency as a standard of exchange and a measurement of value to replace other indigenous currencies had an impact on initiation into regulatory and entertainment societies in Cameroonian communities including the Laimbwe of the North West Region. Male and female institutions eventually began using these currencies during initiation rites. These included nwerong, ngiri, ngumba, takembeng, ndofoumgbui, kwifoyn (also kwifo’o, kwifeu, kuiifuai kefa’a, tschong, libah and ikuum in the grasslands and Liengu, male, ahon, muankum, nganya, monekim, ekpe and obasinjom in the forest region of Cameroon. Prior to the introduction of standard money, some local currencies like cowrie shells were used together with the provision of material things like goats, pigs, fowls and bush meat. Money is effectively a measure of value, status and a store of wealth within the Laimbwe traditional milieu. This paper examines how and why the introduction of money in initiation and other ritual activities led to the emergence of new social classes and the re-enforcement of the socio-political order of the Laimbwe people. The study essentially relies on discussions with members of societies, observation and written material.

  14. Gynaecological morbidity among HIV positive pregnant women in Cameroon

    Directory of Open Access Journals (Sweden)

    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.

  15. On the visibility of airborne volcanic ash and mineral dust

    Science.gov (United States)

    Weinzierl, B.; Sauer, D. N.; Minikin, A.; Reitebuch, O.; Dahlkötter, F.; Mayer, B. C.; Emde, C.; Tegen, I.; Gasteiger, J.; Petzold, A.; Veira, A.; Kueppers, U.; Schumann, U.

    2012-12-01

    aerosol layer and the background, the illumination, the particle size distribution and mass concentration, the wavelength-dependent light scattering and absorption by the aerosol layer, the human perception, etc. In addition, the optical depth along the line of sight through an aerosol layer is more important than just the (vertical) optical depth, which is measured, for example, by sun photometers or satellites. The results of our study are in particular interesting for the question on the visibility of volcanic ash. Our analyses of "visible ash" demonstrate that under clear sky conditions volcanic ash is visible already at concentrations far below what is currently considered as the upper limit for safe operation of an aircraft engine (2 mg m-3). The presence of a grayish-brown layer in the atmosphere does not unambiguously indicate the presence of volcanic ash. An uninformed observer is unlikely to identify an aged volcanic ash layer in his field of view without further information. The presence of clouds would make it even more complicated to visually detect volcanic ash. In regions with high background aerosol loading in the atmosphere from natural or anthropogenic influences, such as seen in large parts of Asia, the visual detection of volcanic ash as an additional contaminant will be substantially more difficult.

  16. MIGRATION AND IDENTITY IN SOUTHWEST REGION OF CAMEROON: THE GRAFFIE FACTOR, C.1930S-1996

    Directory of Open Access Journals (Sweden)

    Walter Gam Nkwi

    2017-09-01

    Full Text Available This article focuses on the dynamics of internal migration taking the case of Bamenda Grassfielders’ migrants in coastal Cameroon and stresses on how such migrations gave rise to the identity puzzle between those who were branded as the graffie and their host. It questions how the politicization of identity can be understood within the historical and political dynamics of Cameroon. The article further maintains that at the onset of the British colonial rule many people from this region migrated to the industrial complex of coastal Cameroon as plantation labour as well as auxiliary labour in other colonial services. After work in these services they retired and became enterprising to the chagrin of their host. They were thus derogatorily branded as graffie. Using the concept of identity in migration the article questions why and how the graffie have coped with their identity in heterogeneous spaces like the South west region of Cameroon.

  17. 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,

  18. 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

  19. Journal of the Cameroon Academy of Sciences - Vol 11, No 1 (2013)

    African Journals Online (AJOL)

    ) Yields in Meme Division, South West Region of Cameroon · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. Martin Keghe Nkobe, Susan Imbolo Mulua, Amougou Joseph Armathée, ...

  20. Occupational exposure to blood, hepatitis B vaccine knowledge and uptake among medical students in Cameroon

    National Research Council Canada - National Science Library

    Noubiap, Jean Jacques N; Nansseu, Jobert Richie N; Kengne, Karen K; Tchokfe Ndoula, Shalom; Agyingi, Lucy A

    2013-01-01

    .... In this study we describe the knowledge of risk factors for HBV infection, history of accidental exposure to blood, awareness of HBV vaccine and the vaccination status among medical students in Cameroon...

  1. SMEs Financing issue in Cameroon in the context of Financial Crises

    OpenAIRE

    NGUENA, Christian L.

    2012-01-01

    Still today Cameroon is suffering from a shy landscape of entrepreneurship and a private sector constituted at 90% by SMEs confronted to a lack of funding; The situation tends to increase with the advent of financial crisis. It is in this framework that this study tries to make an identification and evaluation at descriptive and econometric levels of responsibility of actors involved in the financing problem faced by SMEs in Cameroon. Using a multinomial logit model we estimated our variable ...

  2. Chasing a Pair of Chinese Sandals: Markets and Trade Routes in Cameroon

    OpenAIRE

    Racaud, Sylvain

    2016-01-01

    What are the connections between a village in Cameroon and the transnational network of Chinese junk? From interviews with vendors of Chinese junk and observations of commercial areas, this paper shows territorial dynamics at two ends of the trade route in Cameroon: Douala and the periodic markets in Mont Bamboutos (West). This paper argues that the structuring of the Chinese junk trade route integrates town and countryside in a complementary space produced by commercial relations, appropriat...

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

    Directory of Open Access Journals (Sweden)

    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.

  4. Epidemiology of rotavirus diarrhea in children under 5 years in Northern Cameroon

    OpenAIRE

    Ndze, Valentine Ngum; Akum, Achidi Eric; Kamga, Gonsu Hortense; Enjema, Lyonga Emilia; Esona, Mathew Dioh; Banyai, Krisztian; Therese, Obama Abena Marie

    2012-01-01

    Background Rotavirus still remains the major cause of diarrhea in children below 5 years. No data on rotavirus epidemiology is available in the Northern regions of Cameroon. We aimed to determine the prevalence of group A rotavirus (RVA) in children below 5 years with diarrhea in two regions of Northern Cameroon (North West and Far North Regions) so as to improve our knowledge on the burden of rotavirus disease for imminent introduction of a rotavirus vaccine. Methods Stool samples were colle...

  5. Sismos y volcanes en Colombia

    OpenAIRE

    Duque Escobar, Gonzalo

    2010-01-01

    Notas sobre las zonas de amenaza sísmica y principales fuentes sísmicas de Colombia, y los segmentos volcánicos de los Andes colombianos con los principales volcanes activos, de conformidad con los estudios del Ingeominas. Anexos a títulos con sus correspondientes enlaces, para ofrecer artículos relacionados con sismos y volcanes, en los que se consideran aspectos de interés para la gestión del riesgo sísmico y volcánico en Colombia

  6. Nutrition Transition and Biocultural Determinants of Obesity among Cameroonian Migrants in Urban Cameroon and France.

    Science.gov (United States)

    Cohen, Emmanuel; Amougou, Norbert; Ponty, Amandine; Loinger-Beck, Juliette; Nkuintchua, Téodyl; Monteillet, Nicolas; Bernard, Jonathan Y; Saïd-Mohamed, Rihlat; Holdsworth, Michelle; Pasquet, Patrick

    2017-06-29

    Native of rural West Cameroon, the Bamiléké population is traditionally predisposed to obesity. Bamiléké who migrated to urban areas additionally experience the nutrition transition. We investigated the biocultural determinants of obesity in Bamiléké who migrated to urban Cameroon (Yaoundé), or urban France (Paris). We conducted qualitative interviews ( n = 36; 18 men) and a quantitative survey ( n = 627; 266 men) of adults using two-stage sampling strategy, to determine the association of dietary intake, physical activity and body weight norms with obesity of Bamiléké populations in these three socio-ecological areas (rural Cameroon: n = 258; urban Cameroon: n = 319; urban France: n = 50). The Bamiléké valued overweight and traditional energy-dense diets in rural and urban Cameroon. Physical activity levels were lower, consumption of processed energy-dense food was frequent and obesity levels higher in new migrants living in urban Cameroon and France. Female sex, age, duration of residence in urban areas, lower physical activity and valorisation of overweight were independently associated with obesity status. This work argues in favour of local and global health policies that account for the origin and the migration trajectories to prevent obesity in migrants.

  7. 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

  8. Communication of geohazard risks by focus group discussions in the Mount Cameroon area, Cameroon.

    Science.gov (United States)

    del Marmol, M.-A.; Suh Atanga, M. Bi; Njome, S.; Mafany Teke, G.; Jacobs, P.; Suh, C. E.

    2012-04-01

    The inappropriate translation of scientific information of geohazard (volcanic, landslide and crater lake outgassing) risks to any local population leaves people with incongruent views of the real dangers. Initial workshops organized under the supervision of the VLIR-OI (Flemish Interuniversity Council - Own Initiatives) members have led to the deployment of billboards as requested and drawn up by the locals. The VLIR-OI project has also organized focus group discussions (FGD) with the local stakeholders to find out in various cities, the state of preparedness, the response to emergency situations, the recovery from the emergency and the mitigation. Researchers have preferred open discussion with the local population and its representatives in order to elicit information that otherwise might not be found on a structured questionnaire. FGD provide a meaningful interactive opportunity to collect information and reflection on a wide range of input. The method provides an insight into problems that require a solution through a process of discovering the meaning attributed to certain events or issues. In this research four cardinal points as preparedness, response, recovery and mitigation (Fothergill, 1996) guided the FGD. The population (i.e. local town councils) were constituted by a mix of chiefs, engineers, technicians and civil servants and government officials. In all the three city councils concerned, the engineers in charge complained about the lack of strategic planning, and about the missing of an elaborated strategy for disasters. They are aware of the existence of an organigram in the "Département de l'Action Civile" in Yaounde but never received any "strategic" document. Therefore inappropriate actions might be taken by the municipalities themselves. Fortunately all people interrogated at the FDG always mentioned solidarity in any event. Fothergill, 1996, Gender, Risk, and Disasters, Intern. Jour. of Mass Emergencies and Disasters, vol.14, n°1, 33-56

  9. Timing of Premarital Intercourse in Bandjoun (West Cameroon

    Directory of Open Access Journals (Sweden)

    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.

  10. Wealth and sexual behaviour among men in Cameroon

    Directory of Open Access Journals (Sweden)

    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

  11. SUSTAINABILITY ISSUES IN THE CAMEROON BANANA SUPPLY CHAIN

    Directory of Open Access Journals (Sweden)

    Kingsly Awang Ollong

    2017-01-01

    Full Text Available Bananas are a major staple as well as an important cash crop in developing countries and the most eaten fruit in Europe and Northern America. For decades, the banana economy has been a key example of trade injustice. The concentration of power in the hands of a few multinational companies has negatively affected the lives of thousands of banana workers and small farmers. While this activity has generated considerable profit for the multinational corporations that operate the plantations, the labourers and the communities in which these plantations are found have suffered injustices in the hands of the companies. It is against this backdrop that this paper sets out to make an appraisal of some sustainability issues that have gone a long way to affect the lives of both the workers and the communities in the Njombe-Penja area which is one the key banana producing area in Cameroon.

  12. Mechanisms for Quality Assurance of Universities in Cameroon

    Directory of Open Access Journals (Sweden)

    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.

  13. Alcohol use and extramarital sex among men in Cameroon

    Directory of Open Access Journals (Sweden)

    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

  14. Geochemistry of Selected Kaolins from Cameroon and Nigeria

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    Bukalo Nenita N.

    2017-12-01

    Full Text Available The geochemical characteristics of selected kaolins from Cameroon and Nigeria are presented, with an attempt to elucidate on their possible industrial applications by comparing them to world-known kaolin deposits. Major oxides concentrations were subjected to factor analyses in interpreting their relationships. Geochemical indices, including chemical index of alteration (CIA, chemical index of weathering (CIW and the index of compositional variability (ICV were computed and plotted on binary and ternary diagrams to determine the intensity of weathering of the kaolins and discriminate their different source rock types. Kaolinite was the major phase, followed by quartz, illite and goethite as minor phases. Minerals in trace phases included smectite, anatase, muscovite, gibbsite, microcline, palygorskite and calcite. Mean abundances of major oxides in wt% were: SiO2 (56.96>Al2O3 (24.09>Fe2O3 (3.78>TiO2 (1.53> K2O (1.26> MgO (0.27>CaO (0.20>Na2O (0.17>P2O5 (0.05>MnO (0.04. The CIW versus CIA and ICV versus CIA plots showed that most of the kaolins clearly depicted extreme silicate weathering. The current applications of kaolins from Cameroon and Nigeria include ceramics and manufacturing of bricks and tiles. Low MgO, CaO, Na2O, K2O and TiO2 further position the kaolins for pharmaceutics, cosmetics, rubber and plastic applications. Thus, the studied kaolins have the potential to contribute to improved economic development of these countries.

  15. Lead concentrations and labeling of new paint in cameroon.

    Science.gov (United States)

    Gottesfeld, P; Kuepouo, G; Tetsopgang, S; Durand, K

    2013-01-01

    In spite of the availability of substitutes for lead compounds used in paints, manufacturers continue to produce these paints for decorative and industrial applications. We report here on the concentration of lead in new paint sold in Cameroon and provide a summary of labeling practices on paints available in the country, based on a market survey. Investigators visited 76 retail and wholesale paint suppliers in Cameroon to collect information from paint product labels and to collect samples of paints to analyze for lead content. Only 8.5% of paints had labels identifying any of the ingredients, and none of the lead paints included any warning language. Based on a convenience sample (weighted to include multiple colors from the most common brands), 61 mostly enamel paints were purchased from retail outlets and analyzed for lead content (median: 2150 ppm; range: paint samples had concentrations exceeding the U.S. standard of 90 ppm total lead. All but one of the samples with lead concentrations greater than 90 ppm were also greater than 600 ppm. The largest manufacturer in the country-Seigneurie, a subsidiary of the U.S.-based company PPG-had significant lead concentrations in 9 out of 22 (41%) paints tested. There is an immediate need to adopt mandatory standards to limit the lead content of paint manufactured, imported, and sold in the country. To promote safer paint products we recommend the development of a third-party certification program for paints without added lead. These recommendations are consistent with the objectives of the Global Alliance to Eliminate Lead Paint established under the auspices of the United Nations to address this problem on a global scale.

  16. 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.

  17. Geochemistry of Selected Kaolins from Cameroon and Nigeria

    Science.gov (United States)

    Bukalo, Nenita N.; Ekosse, Georges-Ivo E.; Odiyo, John O.; Ogola, Jason S.

    2017-12-01

    The geochemical characteristics of selected kaolins from Cameroon and Nigeria are presented, with an attempt to elucidate on their possible industrial applications by comparing them to world-known kaolin deposits. Major oxides concentrations were subjected to factor analyses in interpreting their relationships. Geochemical indices, including chemical index of alteration (CIA), chemical index of weathering (CIW) and the index of compositional variability (ICV) were computed and plotted on binary and ternary diagrams to determine the intensity of weathering of the kaolins and discriminate their different source rock types. Kaolinite was the major phase, followed by quartz, illite and goethite as minor phases. Minerals in trace phases included smectite, anatase, muscovite, gibbsite, microcline, palygorskite and calcite. Mean abundances of major oxides in wt% were: SiO2 (56.96)>Al2O3 (24.09)>Fe2O3 (3.78)>TiO2 (1.53)> K2O (1.26)> MgO (0.27)>CaO (0.20)>Na2O (0.17)>P2O5 (0.05)>MnO (0.04). The CIW versus CIA and ICV versus CIA plots showed that most of the kaolins clearly depicted extreme silicate weathering. The current applications of kaolins from Cameroon and Nigeria include ceramics and manufacturing of bricks and tiles. Low MgO, CaO, Na2O, K2O and TiO2 further position the kaolins for pharmaceutics, cosmetics, rubber and plastic applications. Thus, the studied kaolins have the potential to contribute to improved economic development of these countries.

  18. 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.

  19. [Household behaviour regarding health and drug consumption in Cameroon].

    Science.gov (United States)

    Commeyras, Christophe; Ndo, Jean Rolin; Merabet, Omar; Kone, Hamidou; Rakotondrabe, Faraniaina Patricia

    2006-01-01

    To begin a renewal of national health policy in Cameroon, a steering committee from the Cameroon Ministry of Health and its partners sought to analyze health demand through a national population survey and supply capacity through a national survey of retail drug stores. A survey of healthcare consumers was also conducted. The present publication describes the results of the population survey. It measured perceived, rather than objective (diagnosed), morbidity. The morbidity ratio, defined as the proportion of persons who reported having been ill during the reference period, two weeks before the survey, was measured at 23% and varied with demographic, social, and economic characteristics such as age, sex, poverty, the sex and educational level of the head of the household, and place of residence (urban or rural). We asked about six types of response to illness: modern consultation, traditional consultation, modern self-medication, traditional self-medication, expectant management, and prayer. The approaches of individual therapeutic itineraries fluctuated for each subject, depending first on financial capacity, second on geographic accessibility, and third on socio-cultural perception of the illness, which governed in particular choice of a modern or traditional approach. Thus, less than a quarter of all subjects initially chose consultation in a health care centre, which accounted for only 31% of all approaches, and 37% of the effective health responses (excluding treatment abstention). Half, however, chose it as a second step, and 40% as a third. Globally, 56% of those who reported illness did not seek a modern consultation during this illness, and 23% of those who took three separate steps for the same illness never sought a modern consultation. Half of all household health expenditures were for medication, and this proportion was highest in the poorest population. In 2002, the population spent 366 billion CFA Francs on health care: 170 billion for drugs, 75

  20. Page 1 JOURNAL OF THE CAMEROON ACADEMY OF SCIENCES ...

    African Journals Online (AJOL)

    dence for Upper Pleistocene volcanic activity in Annobon. Helium released by crushing is practically similar at 7.88 - 8.64R, (mean = 8.28 + 0.29 R) indicating that the Annobon magma source has a. MORB-like He/He ratio. Key words: Annobon, xenolith, MORB-like He, cosmogenic He, eruption age. RESUME.

  1. Potential volcanic impacts on future climate variability

    Science.gov (United States)

    Bethke, Ingo; Outten, Stephen; Otterå, Odd Helge; Hawkins, Ed; Wagner, Sebastian; Sigl, Michael; Thorne, Peter

    2017-11-01

    Volcanic activity plays a strong role in modulating climate variability. Most model projections of the twenty-first century, however, under-sample future volcanic effects by not representing the range of plausible eruption scenarios. Here, we explore how sixty possible volcanic futures, consistent with ice-core records, impact climate variability projections of the Norwegian Earth System Model (NorESM) under RCP4.5 (ref. ). The inclusion of volcanic forcing enhances climate variability on annual-to-decadal timescales. Although decades with negative global temperature trends become ~50% more commonplace with volcanic activity, these are unlikely to be able to mitigate long-term anthropogenic warming. Volcanic activity also impacts probabilistic projections of global radiation, sea level, ocean circulation, and sea-ice variability, the local-scale effects of which are detectable when quantifying the time of emergence. These results highlight the importance and feasibility of representing volcanic uncertainty in future climate assessments.

  2. 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

  3. The San Franciscan volcanic field, Arizona

    Science.gov (United States)

    Robinson, Henry Hollister

    1913-01-01

    LOCATION OF AREAThe San Franciscan volcanic field, which takes its name from San Francisco Mountain, the largest volcano of the group, covers about 3,000 square miles in the north-central part of Arizona, as shown by the shaded space on the index map forming figure 1. The center of the field lies about 50 miles south of the Grand Canyon of the Colorado and the southern boundary is in part coterminous with that of the San Francisco Plateau, which forms the southwestern division of the great Colorado Plateau.The region is easily reached, for the main line of the Atchison, Topeka, & Santa Fe Railway traverses it from east to west for more than 60 miles. Flagstaff, a town of 1,500 inhabitants 10 miles south of the summit of San Francisco Mountain, is on the railroad, amid a branch line runs from Williams, 34 miles farther west, to the Grand Canyon. All the more important points of interest in the field may be reached without difficulty by wagon, and outfits may be obtained at Flagstaff.OUTLINE OF THE REPORTThis report deals primarily with the volcanic phenomena of the region as determined in the field and laboratory. Chapter I contains a brief description of the geography of the field and Chapter II is devoted largely to the sedimentary formations and structure. The rest of the report Chapters III to VI—treats entirely of the various features of the volcanoes and igneous rocks, both individually and collectively. Detailed descriptions of the volcanoes and lava fields are given in Chapter III; the volcanic history of the region and its correlation with the general history of the surrounding country are presented in Chapter IV. These two chapters will presumably suffice for the general reader who may desire to become acquainted with the broader volcanic features of the region. Chapter V (Petrography) is devoted entirely to the detailed description of the individual igneous rocks of the region, as represented by a selected set of type specimens. In Chapter VI (Petrology

  4. 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. © 2015 The Author(s).

  5. Development of the Oil Industry in Cameroon and Its Implications for Education and Training. IIEP Research Report No. 79.

    Science.gov (United States)

    Sanyal, Bikas C.; And Others

    A study analyzed how the oil industry in Cameroon developed and influenced the expansion, structure, and content of Cameroon's formal and nonformal education and training system. A survey of 213 employees and 8 enterprises was supplemented by a review of government reports and official published and unpublished documents. The economy of Cameroon…

  6. 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.

  7. 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.

  8. Detection of emerging HIV variants in blood donors from urban areas of Cameroon.

    Science.gov (United States)

    Lee, S; Wood, O; Tang, S; Hu, J; Machuca, A; Kerby, S; Awazi, B; Vockley, C; Hewlett, I

    2007-10-01

    The U.S. Food and Drug Administration has licensed several assays for use in donor testing and management of persons with human immunodeficiency virus (HIV) infection. However, the performance of these assays for detection and quantitation of emerging HIV genetic variants has not been studied extensively. We tested 240 human plasma specimens collected from two urban blood centers in Cameroon where HIV genetic diversity and recombinant HIV strains are highly prevalent, using several FDA licensed assays. The testing record in Cameroon indicated that 149 specimens were HIV antibody positive and 91 specimens were negative using a rapid HIV-1/2 antibody assay in routine use in Cameroon blood centers. Both sets of samples were evaluated in the FDA laboratory using four ELISA tests for HIV-1 group M, HIV-1 group O, and HIV-2 antibodies, one IFA for HIV-1 antibody, one Western blot for HIV-1, one HIV-1 p-24 antigen assay, and three nucleic acid tests (NAT). Our results indicate that the assays had high sensitivity for detection of emerging genetic variants, although a small number of samples harboring circulating recombinant forms (CRFs) found in Cameroon were not always consistently detected by a few assays. These findings may be due to the evolving genetic diversity of HIV strains in Cameroon.

  9. 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 (volcano risk in the Andean region. But much remains to be done.

  10. 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.

  11. Disruptive event analysis: volcanism and igneous intrusion

    Energy Technology Data Exchange (ETDEWEB)

    Crowe, B.M.

    1980-08-01

    An evaluation is made of the disruptive effects of volcanic activity with respect to long term isolation of radioactive waste through deep geologic storage. Three major questions are considered. First, what is the range of disruption effects of a radioactive waste repository by volcanic activity. Second, is it possible, by selective siting of a repository, to reduce the risk of disruption by future volcanic activity. And third, can the probability of repository disruption by volcanic activity be quantified. The main variables involved in the evaluation of the consequences of repository disruption by volcanic activity are the geometry of the magma-repository intersection (partly controlled by depth of burial) and the nature of volcanism. Potential radionuclide dispersal by volcanic transport within the biosphere ranges in distance from several kilometers to global. Risk from the most catastrophic types of eruptions can be reduced by careful site selection to maximize lag time prior to the onset of activity. Certain areas or volcanic provinces within the western United States have been sites of significant volcanism and should be avoided as potential sites for a radioactive waste repository. Examples of projection of future sites of active volcanism are discussed for three areas of the western United States. Probability calculations require two types of data: a numerical rate or frequency of volcanic activity and a numerical evaluation of the areal extent of volcanic disruption for a designated region. The former is clearly beyond the current state of art in volcanology. The latter can be approximated with a reasonable degree of satisfaction. In this report, simplified probability calculations are attempted for areas of past volcanic activity.

  12. Mechanical interaction between volcanic systems in Libya

    Science.gov (United States)

    Elshaafi, Abdelsalam; Gudmundsson, Agust

    2018-01-01

    The spatial distributions of monogenetic volcanoes, primarily volcanic craters, within the four principal volcanic provinces of Libya are examined and presented on a volcano-density map. Six main volcanic clusters have been identified, referred to as volcanic systems. Remarkably, the Al Haruj (AHVP) and Nuqay (NVP) volcanic provinces have double-peak volcano-density distributions, while the Gharyan (GVP) and As Sawda (SVP) volcanic provinces have single-peak volcano-density distributions. We interpret each volcano-density peak as corresponding to a separate volcanic system, so that there is a total of six systems in these four provinces. There was an overlap in volcanic activity in these provinces with at least three simultaneously active. We propose that each of the 6 volcanic systems was/is supplied with magma from a large sill-like reservoir - similar in lateral dimensions to the systems/clusters themselves. Numerical results show zones of high tensile and shear stresses between the reservoirs that coincide roughly with the main swarms of extension (dykes and volcanic fissures) and shear (faults) fractures in the areas. The most recent volcanic eruptions in Libya fall within the modelled high-stress concentration zones, primarily eruptions in the volcano Waw an Namus and the Holocene Al Mashaqaq lava flow. There are no known eruptions in Libya in historical time, but some or all the volcanic systems may have had one or more arrested historical dyke injections. In particular, part of the recurrent seismic events in the Hun Graben in the northwest Libya may be related to dyke propagation and arrest. If some of the inferred magma reservoirs are still fluid, as is likely, they pose earthquake and volcanic hazards to parts of Libya, particularly to the city of Gharyan and Zallah town, as well as to many oil-field operations.

  13. The pace of arc volcanism

    Science.gov (United States)

    Palmer, M. R.; Fraass, A. J.; Hatfield, R. G.; McCanta, M. C.

    2016-12-01

    Being able to reconstruct the long-term history of activity at an island arc volcanic centre has important implications for a wide variety of geologic processes. On-land records are frequently incomplete and radiometric dating is complicated in many systems. Here, we describe the application of rapid and non-destructive measurements of sediment physical properties (colour reflectance, gamma ray attenuation and magnetic susceptibility) from marine sediments recovered from IODP site U1396 to produce a tephra index (TI). This approach is combined with palaeomagnetic and foram isotope stratigraphy to yield a 4.5 Myr record of volcanic activity in the northern Lesser Antilles. Pb isotope data on visible tephra layers and volcanological models suggest the tephra is predominantly derived from the nearby island of Montserrat. When examined over a range of time-averaged intervals, the TI record shows long term (order 106 year) cycles of relative quiescence and heightened activity. In accordance with the model of Hall & Kincaid (2001, Science, 292, 2472), this record suggests that the long-term pace of volcanic activity in the northern Lesser Antilles is established by diapirs rising from deep within the mantle wedge. The diapirs do not themselves act as the major source of melt, but rather they create a conduit network that facilitates the rapid rise of melt to the surface. Within the order 106 year cycles, there are shorter-term fluctuations (order 104 years) that may reflect cycles of edifice growth and destruction, and/or pulses of melt rising through conduit networks established by the rising diapirs. The U1396 TI record provides the most complete and non-aliased long-term record of activity at an island arc volcanic center yet determined. It thus provides the first field evidence that can be used to test models of the deep mantle processes that control the pace of arc volcanism. Importantly, the approach presented here is readily applicable to other arc and island

  14. The Eruptive History of the Talpa-Mascota-San Sebastian Volcanic Field in Western Mexico.

    Science.gov (United States)

    Ownby, S.; Lange, R.; Carmichael, I. S.; Hall, C.

    2004-12-01

    The eruptive history of the Talpa-Mascota-San Sebastian (TMSS) volcanic field in the Jalisco Block (JB) of western Mexico is presented. The JB is bounded by the Tepic-Zacoalco and Colima grabens, as well as the Middle America Trench where the Rivera plate subducts beneath North America. The TMSS volcanic field spans ˜2030 km2 and contains ˜123 small cones and flows of minette, absarokite, basic hornblende lamprophyre, basaltic andesite, and andesite. The petrology of these lavas is described in Lange and Carmichael (1990, 1991) and Carmichael et al. (1996). Of the ˜123 distinguishable eruptive units within this volcanic field, 26 samples have been dated by the 40Ar/39Ar method, and are combined with 10 dates from a previous abstract and nine dates from the literature (for a total of 45). The oldest lavas (2.35 to 0.5 Ma) are found in the Talpa region, whereas the youngest lavas (predominantly Mexico. These age results confirm that the potassic lavas of Mascota (not unlike those erupted 3-4 Myr ago in the Sierra Nevada batholith; Farmer et al., 2002) are part of line of similar volcanism that youngs to the N-NW. The Los Volcanes field was active from 3.4-1.5 Myr ago (Wallace and Carmichael, 1992), whereas two dates from the Ayutla volcanic field give ages of 4.4 and 4.5 Ma (Righter and Rosas-Elguera, 2001). It thus appears that this line of potassic volcanism within the interior of the Jalisco block is not a coeval "volcanic front", which raises the possibility that it may not be directly related to active subduction of the Rivera plate.

  15. CONTEXTUALIZING THE USE OF THE DIPLOMATIC ALTERNATIVE IN CONFLICT RESOLUTION IN THE DISPUTE BETWEEN NIGERIA AND CAMEROON OVER BAKASSI 1994 -2006

    Directory of Open Access Journals (Sweden)

    Ekpotuatin Charles Ariye

    2017-09-01

    Full Text Available This study focuses on the subject of the application of alternative means as a complement to the judicial, adjudication and arbitration options in the resolution of disputes/conflicts. The Nigeria-Cameroon conflict over Bakassi is used as a case in point. By blending the theoretical perspectives on the diplomacy/negotiation approach with the reality of this case it argues that the application of alternative dispute resolution mechanism, in this instance, facilitated a long lasting and negotiated settlement, which led to amicable and final resolution. With the understanding that dispute/conflict resolution seeks to find solutions acceptable to both parties to achieve peaceful coexistence, the question arises as to whether the ICJ’s ruling in itself was able to amicably resolve the dispute? What we find is that the Ruling of 2002 did not in itself lead to instant settlement, rather it drew negative responses from Nigeria, so that it took the intervention of stakeholders in the international system, especially the Western countries, and particularly the UN and its then Secretary-General, Kofi Annan, to activate the UN machinery to put in place direct bilateral talks between Nigeria and Cameroon to iron out their differences. The emergent Mixed Commission and the Greentree Agreement of 2006 ensured the achievement of reconciliation, lasting peace and final resolution along the lines of the ICJ’s Judgment of 2002.

  16. The Cameroon Press Photo Archive (CPPA Buea in Crisis 1955-2016

    Directory of Open Access Journals (Sweden)

    Solomon Kekeisen Nsah

    2017-06-01

    Full Text Available Since its invention photography in all its ramifications has affected and continues to affect the everyday life of people. It has become a powerful means of communication and mode of visual expression that touches human life in many ways. For example, photography is valued as a means of crystallising memories. One archive which illustrates it is the Cameroon Press Photo Archives - Buea (CPPA-B. The CPPA-Buea was established to use photography as a means of immortalising, conserving and granting access to historical events and personalities in British Southern Cameroons. More than fifty-five years later the institution has not only been in crisis but has been basically abandoned by the authorities in charge. Through qualitative analysis, this paper traces the origin and evolution of the CPPA, its challenges, prospects and ongoing reforms between 1955 and 2016. Keywords: Photo Archives, Photography, Cameroon Press

  17. 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.

  18. Oral health status of diabetes mellitus patients in Southwest Cameroon.

    Science.gov (United States)

    Bissong, Mea; Azodo, C C; Agbor, M A; Nkuo-Akenji, T; Fon, P Nde

    2015-06-01

    Diabetes mellitus affects virtually all tissues and organs the body including the hard and soft issues of the oral cavity, manifesting with several complications. To assess the prevalence of oral diseases in diabetics and non-diabetics and to correlate oral diseases with glycaemic control. This was an observational study involving 149 diabetic patients recruited from hospitals in Southwest Region of Cameroon and 102 non-diabetic controls drawn from the general population. The study participants were aged 18 years and above. Data were collected using questionnaires, oral examination and laboratory tests. Oral examination was conducted to assess dental plaque, calculus, dental caries, periodontitis, gingivitis and candidiasis. Glycemic status was assessed by measuring glycated hemoglobin (HbA1c) levels using standardized methods. Thirty five out of 149 (23.5%) diabetic patients had gingivitis; 37 (24.8%) had periodontitis; 29 (19.5%) had dental caries and 32 (21.5%) had oral candidiasis. Gingivitis, periodontitis and oral candidiasis was significantly higher in diabetics than non-diabetics (P diabetic patients presented with poor oral hygiene than non-diabetics. Poorly controlled diabetics presented more with gingivitis and candidiasis than well-controlled diabetics and this relationship was statistically significant. The prevalence of oral disease was significantly higher in diabetics than in non-diabetic controls and hyperglycaemia seemed to be a major contributor to oral health in diabetic patients in the study area. Proper management of blood sugar levels might improve on the oral health of diabetes mellitus patients.

  19. [Descriptive study of cerebrovascular accidents in Douala, Cameroon].

    Science.gov (United States)

    Chiasseu, Mbeumi M T; Mbahe, S

    2011-10-01

    A cerebrovascular accident or stroke is a sudden-onset cerebral deficit of vascular origin lasting more than 24 hours. These events represent the second leading cause of death in the world and take a particularly heavy toll in third world countries. The purpose of this study was to describe cerebrovascular lesions (type, location, size) as well as patient age and gender in Cameroon. Brain CT-scan and MRI findings from 50 stroke patients admitted to two health centers in Douala were reviewed. Data showed that 74% of patients were over 50 years of age, the 51-60 year group being the most affected. Patients were male in 64% of cases. Ischemic stroke accounted for 60% of cases versus 40% for hemorrhagic stroke. The most affected sites were the sylvian territory site in ischemic stroke and the temporal lobe in hemorrhagic stroke, acconting for 43.3% and 35% of cases respectively. The median size of ischemic and hemorrhagic lesions were 2.81 cm3, and 26.98 cm3 respectively. Hemorrhagic stroke and lacunar infarcts were more common in this sample. Discrepancies between results at the two hospitals may be due to the use of different imaging techniques. Indeed, MRI is known to be more sensitive than CT-scan for acute detection of stroke lesions.

  20. Modeling Fuel Choice among Households in Northern Cameroon

    Directory of Open Access Journals (Sweden)

    Jean Hugues Nlom

    2015-07-01

    Full Text Available The present study aims to explore economic and socio-demographic factors that influence a household’s probability to switch from firewood to cleaner fuels (kerosene and LPG in northern Cameroon. The paper employs an ordered probit model to construct cooking patterns and fuel choices. Three main cooking sources are considered: firewood, kerosene, and liquefied petroleum gas. Utilized data are derived from a national survey conducted in 2004 by the Cameroonian National Institute of Statistics. The study analyzes the data related to the Sudano-Sahelian agro-ecological zone, which is one of the most affected by land degradation and decertification. While results indicate that there is a potential for a transition from traditional to cleaner fuels in the studied region, this transition is still in its earlier stage. The research demonstrates that firewood and kerosene prices, age of household heads, educational level of household heads and willingness to have a gas cylinder, as well as type of dwelling have a statistically significant impact on fuel-switching decisions.

  1. Self medication for oral health problems in Cameroon.

    Science.gov (United States)

    Agbor, Michael A; Azodo, Clement C

    2011-08-01

    To assess the use of self medication in oral health problems in Cameroon. This multi-regional cross-sectional survey was conducted in three towns; Bamenda, Yaounde and Buea over a 10 month period. The questionnaire elicited information on demography, oral problem for self medication, substance used for self medication, source of the substance, duration of self medication, reason for self medication, source of advice of the drugs or those products used, opinion about the substance, effect and duration. The prevalence of self medication for oral health problems was 67.8% which was significantly associated with age, marital status and location. The most frequently self medicated oral health problem was toothache (54.7%). The majority (64.5%) of the respondents used pharmaceutical products while a minority (7.7%) used dangerous substances such as petrol and vinegar for self medication. Sources of substances of self medication included pharmacy (55.6%), road side vendors (26.1%), native healers (7.8%), mobile drug vendors in buses (5.3%), and others (5.3%). The choice of substances used for self medication was mostly guided by the advice from relatives. The majority of the respondents self-medicated for oral health problems. Unmarried, urban residents, aged 21-30 years reported significantly increased self-medication for oral health problems. Evidently dangerous substances were utilised for self-medication in this study, necessitating awareness and other forms of intervention. © 2011 FDI World Dental Federation.

  2. Petrology of peraluminous and peralkaline rhyolites from the SE Lake Chad (northernmost Cameroon Line)

    Science.gov (United States)

    Mbowou, Gbambié Isaac Bertrand; Botelho, Nilson Francisquini; Lagmet, Claudial Amane; Ngounouno, Ismaïla

    2015-12-01

    Peraluminous (P.I. peralkaline (P.I. > 1) rhyolites from SE Lake Chad consisted of quartz, alkali feldspar and oxides-hydroxides phenocrysts, display negative Eu anomaly. F-arfvedsonite, augite-hedenbergite, aegirine and aegirine-augite are present in peralkaline rhyolites. The peralkaline and peraluminous rhyolitic magmas of the SE Lake Chad derive likely from the same source, according to their coexistence on the same volcano (Hadjer Bigli); their similar Zr/Nb, Zr/Hf ratios and their linear trends established in Zr vs Nb, Zr vs Ta and Zr vs Y diagrams, which linked to removal of successive batches of magma from a mantle source or to different degrees of partial melting. These magmas generated from the partial melting model of the underplated mantle, which would have induced the intrusion of crustal materials, triggering the hydrothermal reactions. Although, the high Zr amounts are not related to bulk assimilation of partially melted crustal materials.

  3. Volcanic caves of East Africa - an overview

    OpenAIRE

    Jim W. Simons

    1998-01-01

    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 are...

  4. Achieving high uptake of human papillomavirus vaccine in Cameroon: lessons learned in overcoming challenges.

    Science.gov (United States)

    Ogembo, Javier Gordon; Manga, Simon; Nulah, Kathleen; Foglabenchi, Lily H; Perlman, Stacey; Wamai, Richard G; Welty, Thomas; Welty, Edith; Tih, Pius

    2014-07-31

    Cameroon has the highest age-standardized incidence rate of cervical cancer (30/100,000 women) in Central Africa. In 2010-2011, the Cameroon Baptist Convention Health Services (CBCHS) received donated human papillomavirus (HPV) vaccine, Gardasil, from Merck & Co. Inc. through Axios Healthcare Development to immunize 6400 girls aged 9-13 years. The aim was to inform the Cameroon Ministry of Health (MOH) of the acceptability, feasibility, and optimal delivery strategies for HPV vaccine. Following approval by the MOH, CBCHS nurses educated girls, parents, and communities about HPV, cervical cancer, and HPV vaccine through multimedia coverage, brochures, posters, and presentations. Because educators were initially reluctant to allow immunization in schools, due to fear of adverse events, the nurses performed 40.7% of vaccinations in the clinics, 34.5% in community venues, and only 24.7% in schools. When no adverse events were reported, more schools and communities permitted HPV vaccine immunization on their premises. To recover administrative costs, CBCHS charged a fee of US$8 per 3-dose series only to those who were able to pay. Despite the fee, 84.6% of the 6,851 girls who received the first dose received all three doses. With adequate education of all stakeholders, HPV vaccination is acceptable and feasible in Cameroon. Following this demonstration project, in 2014 the Global Access to Vaccines and Immunization (GAVI) Alliance awarded the Cameroon MOH HPV vaccine at a price of US$4.50 per dose to immunize sixth grade girls and girls aged 10 years who are not in school in two districts of Cameroon. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. 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...

  6. Felsic Volcanics on the Moon

    Science.gov (United States)

    Jolliff, B. L.; Lawrence, S. J.; Stopar, J.; Braden, S.; Hawke, B. R.; Robinson, M. S.; Glotch, T. D.; Greenhagen, B. T.; Seddio, S. M.

    2012-12-01

    Lunar Reconnaissance Orbiter (LRO) imaging and thermal data provide new morphologic and compositional evidence for features that appear to be expressions of nonmare silicic volcanism. Examples reflecting a range of sizes and volcanic styles include the Gruithuisen and Mairan Domes, and the Hansteen Alpha (H-A) and Compton-Belkovich (C-B) volcanic complexes. In this work we combine new observations with existing compositional remote sensing and Apollo sample data to assess possible origins. Images and digital topographic data at 100 m scale (Wide Angle Camera) and ~0.5 to 2 m (Narrow Angle Camera) reveal (1) slopes on volcanic constructs of ~12° to 27°, (2) potential endogenic summit depressions, (3) small domical features with dense boulder populations, and (4) irregular collapse features. Morphologies in plan view range from the circular to elliptical Gruithuisen γ and δ domes (~340 km2 each), to smaller cumulodomes such as Mairan T and C-B α (~30 km2, each), to the H-A (~375 km2) and C-B (~680 km2) volcanic complexes. Heights range from ~800-1800 m, and most domes are relatively flat-topped or have a central depression. Positions of the Christiansen Feature in LRO Diviner data reflect silicic compositions [1]. Clementine UVVIS-derived FeO varies from ~5 to 10 wt%. Lunar Prospector Th data indicate model values of 20-55 ppm [2,3], which are consistent with compositions ranging from KREEP basalt to lunar granite. The Apollo collection contains small rocks and breccia clasts of felsic/granitic lithologies. Apollo 12 samples include small, pristine and brecciated granitic rock fragments and a large, polymict breccia (12013) consisting of felsic material (quartz & K-feldspar-rich) and mafic phases (similar to KREEP basalt). Many of the evolved lunar rocks have geochemically complementary compositions. The lithologic associations and the lack of samples with intermediate composition suggest a form of magmatic differentiation that produced mafic and felsic

  7. Volcanic hazards and public response

    Science.gov (United States)

    Peterson, Donald W.

    1988-05-01

    Although scientific understanding of volcanoes is advancing, eruptions continue to take a substantial toll of life and property. Some of these losses could be reduced by better advance preparation, more effective flow of information between scientists and public officials, and better understanding of volcanic behavior by all segments of the public. The greatest losses generally occur at volcanoes that erupt infrequently where people are not accustomed to dealing with them. Scientists sometimes tend to feel that the blame for poor decisions in emergency management lies chiefly with officials or journalists because of their failure to understand the threat. However, the underlying problem embraces a set of more complex issues comprising three pervasive factors. The first factor is the volcano: signals given by restless volcanoes are often ambiguous and difficult to interpret, especially at long-quiescent volcanoes. The second factor is people: people confront hazardous volcanoes in widely divergent ways, and many have difficulty in dealing with the uncertainties inherent in volcanic unrest. The third factor is the scientists: volcanologists correctly place their highest priority on monitoring and hazard assessment, but they sometimes fail to explain clearly their conclusions to responsible officials and the public, which may lead to inadequate public response. Of all groups in society, volcanologists have the clearest understanding of the hazards and vagaries of volcanic activity; they thereby assume an ethical obligation to convey effectively their knowledge to benefit all of society. If society resists, their obligation nevertheless remains. They must use the same ingenuity and creativity in dealing with information for the public that they use in solving scientific problems. When this falls short, even excellent scientific results may be nullified.

  8. K-AR AGES, MINERALOGY, MAJOR AND TRACE ELEMENT ...

    African Journals Online (AJOL)

    The Ndu Volcanic Ridge occupies the central position amongst the continental sector volcanoes of the Cameroon Volcanic Line. K-Ar age determination coupled with field observations show that there were three episodes of volcanic manifestation: 31-28 Ma; 23-21 Ma and <1 Ma. Basaltic magmas were erupted during the ...

  9. Download this PDF file

    African Journals Online (AJOL)

    active volcano on the continental sector of the Cameroon. Volcanic Line (CVL). Mount Cameroon erupted.6 times in the last century (1909, 1922, 1954, 1959, 1982 and. 1999). It entered into another session of active eruption this century on the 28* May 2000 (Figure 1). Fako Division has relatively high rainfall, with.

  10. Page 1 JOURNAL OFTHE CAMEROONACADEMYOFSCIENCES ...

    African Journals Online (AJOL)

    active volcano on the continental sector of the Cameroon. Volcanic Line (CVL). Mount Cameroon erupted.6 times in the last century (1909, 1922, 1954, 1959, 1982 and. 1999). It entered into another session of active eruption this century on the 28* May 2000 (Figure 1). Fako Division has relatively high rainfall, with.

  11. A Ground Deformation Monitoring Approach to Understanding Magma Chamber Systems and Eruptive Cycles of Mount Cameroon

    Science.gov (United States)

    Riley, S.; Clarke, A.

    2005-05-01

    Mount Cameroon is a 13,400ft basanite volcano on the passive margin of West Africa. It has erupted seven times in the past century making it one of the most active volcanoes in Africa. Most recently Mount Cameroon erupted in 1999 and 2000 first issuing strombolian explosions from vents near the summit, and later erupting effusively from a fissure running southwest from the summit (Suh et al., 2003). Prior to 2004, the only monitoring equipment on Mount Cameroon was a small seismometer network installed following the 1982 eruption. By 1999 only a single seismometer in the network was functional. Seismic activity did not rise above background levels until the few days immediately preceding the eruption. In an effort to raise awareness of the volcano's condition and provide a more efficient warning of impending eruptions we have begun constructing a ground deformation network on Mount Cameroon. The new network currently consists of two Applied Geomechanics 711-2A(4X) biaxial tiltmeters capable of resolving 0.1 microradians of tilt. One station is located approximately 500 m from the 2000 summit vent, and the other is approximately 1km away from the central fissure approximately 5km southwest of the 2000 summit vent. Three primary processes could precede eruptions at Mt. Cameroon, offering the opportunity for detection and prediction by our network. These processes are magma chamber pressurization, magma ascent via a central conduit, and/or propagation of magma along the central fissure. Magma chamber location, if a significant chamber exists, is poorly constrained, however, previous petrologic studies on Mount Cameroon (Suh et al., 2003; Fitton et al., 1983) suggest Mount Cameroon magmas originate at a depth less than 40km. Published seismic data (Ambeh, 1989) contains evidence of magmatic activity and possible chambers at depths ranging from 10km to 70km. Preliminary calculations using a simple Mogi model suggest deformation caused by pressurization of a large

  12. Mind the gap: knowledge and practice of providers treating uncomplicated malaria at public and mission health facilities, pharmacies and drug stores in Cameroon and Nigeria.

    Science.gov (United States)

    Mangham-Jefferies, Lindsay; Hanson, Kara; Mbacham, Wilfred; Onwujekwe, Obinna; Wiseman, Virginia

    2015-11-01

    Artemisinin combination therapy (ACT) has been the first-line treatment for uncomplicated malaria in Cameroon since 2004 and Nigeria since 2005, though many febrile patients receive less effective antimalarials. Patients often rely on providers to select treatment, and interventions are needed to improve providers' practice and encourage them to adhere to clinical guidelines. Providers' adherence to malaria treatment guidelines was examined using data collected in Cameroon and Nigeria at public and mission facilities, pharmacies and drug stores. Providers' choice of antimalarial was investigated separately for each country. Multilevel logistic regression was used to determine whether providers were more likely to choose ACT if they knew it was the first-line antimalarial. Multiple imputation was used to impute missing data that arose when linking exit survey responses to details of the provider responsible for selecting treatment. There was a gap between providers' knowledge and their practice in both countries, as providers' decision to supply ACT was not significantly associated with knowledge of the first-line antimalarial. Providers were, however, more likely to supply ACT if it was the type of antimalarial they prefer. Other factors were country-specific, and indicated providers can be influenced by what they perceived their patients prefer or could afford, as well as information about their symptoms, previous treatment, the type of outlet and availability of ACT. Public health interventions to improve the treatment of uncomplicated malaria should strive to change what providers prefer, rather than focus on what they know. Interventions to improve adherence to malaria treatment guidelines should emphasize that ACT is the recommended antimalarial, and it should be used for all patients with uncomplicated malaria. Interventions should also be tailored to the local setting, as there were differences between the two countries in providers' choice of antimalarial

  13. Volcanic eruptions; energy and size

    Science.gov (United States)

    de la Cruz-Reyna, S.

    1991-01-01

    The Earth is a dynamic planet. Many different processes are continuously developing, creating a delicate balance between the energy stored and generated in its interior and the heat lost into space. The heat in continuously transferred through complex self-regulating convection mechanisms on a planetary scale. The distribution of terrestrial heat flow reveals some of the fine structure of the energy transport mechanisms in the outer layers of the Earth. Of these mechanisms in the outer layers of the Earth. Of these mechanisms, volcanism is indeed the most remarkable, for it allows energy to be transported in rapid bursts to the surface. In order to maintain the subtle balance of the terrestrial heat machine, one may expect that some law or principle restricts the ways in which these volcanic bursts affect the overall energy transfer of the Earth. For instance, we know that the geothermal flux of the planet amounts to 1028 erg/year. On the other hand, a single large event like the Lava Creek Tuff eruption that formed Yellowstone caldera over half a million years ago may release the same amount of energy in a very small area, over a short period of time. 

  14. Small global-mean cooling due to volcanic radiative forcing

    Science.gov (United States)

    Gregory, J. M.; Andrews, T.; Good, P.; Mauritsen, T.; Forster, P. M.

    2016-12-01

    In both the observational record and atmosphere-ocean general circulation model (AOGCM) simulations of the last ˜150 years, short-lived negative radiative forcing due to volcanic aerosol, following explosive eruptions, causes sudden global-mean cooling of up to ˜0.3 K. This is about five times smaller than expected from the transient climate response parameter (TCRP, K of global-mean surface air temperature change per W m-2 of radiative forcing increase) evaluated under atmospheric CO2 concentration increasing at 1 % yr-1. Using the step model (Good et al. in Geophys Res Lett 38:L01703, 2011. doi: 10.1029/2010GL045208), we confirm the previous finding (Held et al. in J Clim 23:2418-2427, 2010. doi: 10.1175/2009JCLI3466.1) that the main reason for the discrepancy is the damping of the response to short-lived forcing by the thermal inertia of the upper ocean. Although the step model includes this effect, it still overestimates the volcanic cooling simulated by AOGCMs by about 60 %. We show that this remaining discrepancy can be explained by the magnitude of the volcanic forcing, which may be smaller in AOGCMs (by 30 % for the HadCM3 AOGCM) than in off-line calculations that do not account for rapid cloud adjustment, and the climate sensitivity parameter, which may be smaller than for increasing CO2 (40 % smaller than for 4 × CO2 in HadCM3).

  15. 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

  16. CO2 flux from Javanese mud volcanism

    Science.gov (United States)

    Queißer, M.; Burton, M. R.; Arzilli, F.; Chiarugi, A.; Marliyani, G. I.; Anggara, F.; Harijoko, A.

    2017-06-01

    Studying the quantity and origin of CO2 emitted by back-arc mud volcanoes is critical to correctly model fluid-dynamical, thermodynamical, and geochemical processes that drive their activity and to constrain their role in the global geochemical carbon cycle. We measured CO2 fluxes of the Bledug Kuwu mud volcano on the Kendeng Fold and thrust belt in the back arc of Central Java, Indonesia, using scanning remote sensing absorption spectroscopy. The data show that the expelled gas is rich in CO2 with a volume fraction of at least 16 vol %. A lower limit CO2 flux of 1.4 kg s-1 (117 t d-1) was determined, in line with the CO2 flux from the Javanese mud volcano LUSI. Extrapolating these results to mud volcanism from the whole of Java suggests an order of magnitude total CO2 flux of 3 kt d-1, comparable with the expected back-arc efflux of magmatic CO2. After discussing geochemical, geological, and geophysical evidence we conclude that the source of CO2 observed at Bledug Kuwu is likely a mixture of thermogenic, biogenic, and magmatic CO2, with faulting controlling potential pathways for magmatic fluids. This study further demonstrates the merit of man-portable active remote sensing instruments for probing natural gas releases, enabling bottom-up quantification of CO2 fluxes.

  17. CO2 flux from Javanese mud volcanism.

    Science.gov (United States)

    Queißer, M; Burton, M R; Arzilli, F; Chiarugi, A; Marliyani, G I; Anggara, F; Harijoko, A

    2017-06-01

    Studying the quantity and origin of CO2 emitted by back-arc mud volcanoes is critical to correctly model fluid-dynamical, thermodynamical, and geochemical processes that drive their activity and to constrain their role in the global geochemical carbon cycle. We measured CO2 fluxes of the Bledug Kuwu mud volcano on the Kendeng Fold and thrust belt in the back arc of Central Java, Indonesia, using scanning remote sensing absorption spectroscopy. The data show that the expelled gas is rich in CO2 with a volume fraction of at least 16 vol %. A lower limit CO2 flux of 1.4 kg s-1 (117 t d-1) was determined, in line with the CO2 flux from the Javanese mud volcano LUSI. Extrapolating these results to mud volcanism from the whole of Java suggests an order of magnitude total CO2 flux of 3 kt d-1, comparable with the expected back-arc efflux of magmatic CO2. After discussing geochemical, geological, and geophysical evidence we conclude that the source of CO2 observed at Bledug Kuwu is likely a mixture of thermogenic, biogenic, and magmatic CO2, with faulting controlling potential pathways for magmatic fluids. This study further demonstrates the merit of man-portable active remote sensing instruments for probing natural gas releases, enabling bottom-up quantification of CO2 fluxes.

  18. Monogenetic volcanism in the Cordillera Central of Colombia: unknown volcanic fields associated with the northernmost Andes' volcanic chain related subduction

    Science.gov (United States)

    Murcia, Hugo; Borrero, Carlos; Németh, Károly

    2017-04-01

    Monogenetic volcanic fields are commonly related to rifts and/or intraplate tectonic settings. However, although less common, they appear also associated with subduction zones, including both front and back-arc volcanoes. To nourish this uncommon tectonic location, it is shown here that monogenetic volcanic fields, in addition to polygenetic volcanoes, also appear at the northernmost part of the Andes Northern Volcanic Zone (NVZ) (2° S to 4°30´N). These fields are associated with the main axe of the Quaternary active volcanic structures; they are linked to the polygenetic Cerro Bravo - Cerro Machín Volcanic Chain ( 80 km long; CBCMVC) in Colombia, the chain that hosts the iconic Nevado del Ruiz volcano. To the present, three monogenetic volcanic fields, with a typical calc-alkaline signature, have been identified in both sides of this chain: 1) Villamaría - Termales Monogenetic Volcanic Field (VTMVF) located to the northwestern part (>5 km) of the CBCMVC. This field is made up of at least 14 volcanoes aligned with the Villamaría - Termales fault zone. The volcanism has been mainly effusive, represented by lava domes and some lava flows. The volcanoes are andesitic to dacitic in composition. It is inferred that the magmatic source is a magma chamber close to Nevado del Ruiz volcano. Based on stratigraphic relationships, it is assumed that the last eruption occurred 10 wt.%) in the whole CBCMVC. Its source is related to the same magmas that feed the volcanoes in the CBCMVC. Stratigraphic relationships show that the volcanoes are younger than the underlying alluvial and volcaniclastic Ibagué fan (<1 Ma). Overall, it is clear that monogenetic volcanic fields are not atypical in the area, although their relationship with the magmatism feeding the polygenetic arc of the Andes' volcanic chain related subduction, is still unknown.

  19. Interpreting gravity anomalies in south Cameroon, central Africa

    Directory of Open Access Journals (Sweden)

    Tadjou Jean Marie

    2012-10-01

    Full Text Available

    The area involved in this study is the northern part of the Congo craton, located in south Cameroon, (2.5°N - 4.5°N, 11°E - 13°E. The study involved analysing gravity data to delineate major structures and faults in south Cameroon. The region’s Bouguer gravity is

  20. Soils of volcanic regions in Europe

    NARCIS (Netherlands)

    Arnalds, O.; Bartoli, F.; Buurman, P.; Oskarsson, H.; Stoops, G.; García-Rodeja, E.

    2007-01-01

    Soils of volcanic areas often exhibit unique properties differentiating them from other soils on Earth. This book gives comprehensive coverage of soils in volcanic regions within Europe, dealing with most aspects of modern day soil science. It covers a range of issues such as mineralogy, chemistry,

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

    DEFF Research Database (Denmark)

    Søager, Nina

    primitive basalts and trachybasalts but also more evolved samples from the retroarc region and the larger volcanoes Payún Matrú and Payún Liso are presented. The samples cover a broad range of compositions from intraplate lavas similar to ocean island basalts to arc andesites. A common feature found...... are isotopically similar to the Andean Southern Volcanic Zone arc rocks and their mantle source possibly resembled the source of South Atlantic N-MORB prior to addition of fluids and melts from the subduction channel. However, it must have been more enriched than the estimates of depleted upper mantle from...... the lithosphere is thinnest and possibly in areas of elevated mantle temperatures. The pyroxenite melts formed at deeper levels react with the surrounding peridotite and thereby changes composition leading to eruption of melts which experienced variable degrees of melt-peridotite interaction. This can presumably...

  2. Climate Curriculum Modules on Volcanic Eruptions, Geoengineering, and Nuclear Winter

    Science.gov (United States)

    Robock, A.

    2016-12-01

    To support a climate dynamics multidisciplinary curriculum for graduate and senior university students, I will describe proposed on-line modules on volcanic eruptions and climate, geoengineering, and nuclear winter. Each of these topics involves aerosols in the stratosphere and the response of the climate system, but each is distinct, and each is evolving as more research becomes available. While nature can load the stratosphere with sulfate aerosols for several years from large volcanic eruptions, humans could also put sulfate aerosols into the stratosphere on purpose through geoengineering or soot as a result of the fires from a nuclear war. As reported for the first time in the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, volcanic eruptions are a natural analog for the climate impacts of potential anthropogenic aerosol injections into the stratosphere, either sulfates from potential attempts to cool the climate to counteract global warming, or smoke that would be produced from fires in cities and industrial targets in a nuclear war. Stratospheric aerosols would change the temperature, precipitation, total insolation, and fraction of diffuse radiation due to their radiative impacts, and could produce more ultraviolet radiation by ozone destruction. Surface ozone concentration could also change by changed transport from the stratosphere as well as changed tropospheric chemistry. There would be two options: 1) Each module would stand alone and could be taught independently, or 2) The volcanic eruptions module would stand alone, and would also serve as a prerequisite for each of the other two modules, which could be taught independently of each other. Each module includes consideration of the physical climate system as well as impacts of the resulting climate change. Geoengineering includes both solar radiation management and carbon dioxide reduction. The geoengineering and nuclear winter modules also include consideration of policy and

  3. 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.

  4. The Impact of a Community Mobilization Project on Health-Related Knowledge and Practices in Cameroon.

    Science.gov (United States)

    Babalola, Stella; Sakolsky, Natasha; Vondrasek, Claudia; Mounlom, Damaris; Brown, Jane; Tchupo, Jean-Paul

    2001-01-01

    Evaluated the impact of a reproductive health community mobilization initiative in Cameroon. Baseline and followup survey data indicated that at a rural site, the intervention positively influenced family planning knowledge and practices, HIV/AIDS and sexually transmitted disease knowledge and attitudes, and use of health services. At an urban…

  5. 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

  6. Soil physical and chemical properties of cacao farms in the south western region of cameroon

    Science.gov (United States)

    The low macro nutrient content (K, Ca and Mg) in soils under cacao is one of the major causes of the poor cacao (Theobroma cacao L) yields. Efforts were made to assess the major physical and chemical properties of soils from some important cacao zones of the South West Region of Cameroon in order t...

  7. Journal of the Cameroon Academy of Sciences - Vol 3, No 1 (2003)

    African Journals Online (AJOL)

    The impact of capture and trade in African grey parrot populations (Psittacus erithacus) in Lobeke National Park, south east Cameroon, EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. A Ngenyi, Z Nzooh, L Usongo, 11-16 ...

  8. Journal of the Cameroon Academy of Sciences - Vol 7, No 3 (2008)

    African Journals Online (AJOL)

    The geological control and triggering mechanisms of landslides of 20th July of 2003 within the Bamboutos Caldera, Cameroon · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. SN Ayonghe, EB Ntasin, 191-204 ...

  9. HIV/AIDS and older adults in Cameroon: Emerging issues and ...

    African Journals Online (AJOL)

    Perpetua Lum Tanyi

    2018-02-06

    Feb 6, 2018 ... larger study which had been conducted concerning the burden of HIV infection and AIDS on the older adults in the Northwest. Region of Cameroon. ... population ageing in Africa, has interlocked to not only create new emerging issues but ...... Economic Development and Cultural Change,. 56(2), 441–475.

  10. Genetic structure of the tiger mosquito, Aedes albopictus, in Cameroon (Central Africa).

    Science.gov (United States)

    Kamgang, Basile; Brengues, Cécile; Fontenille, Didier; Njiokou, Flobert; Simard, Frédéric; Paupy, Christophe

    2011-01-01

    Aedes albopictus (Skuse, 1884) (Diptera: Culicidae), a mosquito native to Asia, has recently invaded all five continents. In Central Africa it was first reported in the early 2000s, and has since been implicated in the emergence of arboviruses such as dengue and chikungunya in this region. Recent genetic studies of invasive species have shown that multiple introductions are a key factor for successful expansion in new areas. As a result, phenotypic characters such as vector competence and insecticide susceptibility may vary within invasive pest species, potentially affecting vector efficiency and pest management. Here we assessed the genetic variability and population genetics of Ae. albopictus isolates in Cameroon (Central Africa), thereby deducing their likely geographic origin. Mosquitoes were sampled in 2007 in 12 localities in southern Cameroon and analyzed for polymorphism at six microsatellite loci and in two mitochondrial DNA regions (ND5 and COI). All the microsatellite markers were successfully amplified and were polymorphic, showing moderate genetic structureamong geographic populations (F(ST)  = 0.068, P albopictus in Cameroon. Phylogeographic analysis based on COI polymorphism indicated that Ae. albopictus populations from Cameroon are related to tropical rather than temperate or subtropical outgroups. The moderate genetic diversity observed among Cameroonian Ae. albopictus isolates is in keeping with recent introduction and spread in this country. The genetic structure of natural populations points to multiple introductions from tropical regions.

  11. 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

  12. Journal of the Cameroon Academy of Sciences - Vol 5, No 2 (2005)

    African Journals Online (AJOL)

    Distribution of the Giardia sp cysts in the Mfondi water basin (Cameroon): influence of some physico-chemical factors of the medium · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. AG Ajeagah, SM Foto, T Njine, T Njine, M Wouafo, RS Moyou, M Nola, A Monkiedje, ...

  13. Wind Power Potentials in Cameroon and Nigeria: Lessons from South Africa

    Directory of Open Access Journals (Sweden)

    Abdullahi Abubakar Mas’ud

    2017-03-01

    Full Text Available Wind energy has seen a tremendous growth for electricity generation worldwide and reached 456 GW by the end of June 2016. According to the World Wind Energy Association, global wind power will reach 500 GW by the end of 2016. Africa is a continent that possesses huge under-utilized wind potentials. Some African countries, e.g., Morocco, Egypt, Tunisia and South Africa, have already adopted wind as an alternative power generation source in their energy mix. Among these countries, South Africa has invested heavily in wind energy with operational wind farms supplying up to 26,000 GWh annually to the national grid. However, two African countries, i.e., Cameroon and Nigeria, have vast potentials, but currently are lagging behind in wind energy development. For Nigeria, there is slow implementation of renewable energy policy, with no visible operational wind farms; while Cameroon does not have any policy plan for wind power. These issues are severely hindering both direct foreign and local investments into the electricity sector. Cameroon and Nigeria have huge wind energy potentials with similar climatic conditions and can benefit greatly from the huge success recorded in South Africa in terms of policy implementation, research, development and technical considerations. Therefore, this paper reviews the wind energy potentials, policies and future renewable energy road-maps in Cameroon and Nigeria and identifies their strength and weakness, as well as providing necessary actions for future improvement that South Africa has already adopted.

  14. Neuropeltis eladii (Convolvulaceae), a new species from the South Province of Cameroon

    NARCIS (Netherlands)

    Breteler, F.J.

    2014-01-01

    Background and aims - The paleotropical genus Neuropeltis of the Convolvulaceae was recently treated in a synopsis for the African continent (Breteler 2010), counting nine species. This number is now enlarged by a new, overlooked, species from the South Province of Cameroon. Methods - Normal

  15. 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…

  16. Teachers' Use of Information and Communications Technology in Education: Cameroon Secondary Schools Perspectives

    Science.gov (United States)

    Haji, Shaibou Abdoulai; Moluayonge, Gracemary Eloheneke; Park, Innwoo

    2017-01-01

    Information and Communications Technology (ICT) offers innovative tools for restructuring teaching and learning processes in preparing students for the 21st Century skills. However, there is no sufficient and reliable data concerning how the use of ICT fit in different school cultures in Cameroon, and how teachers with varying pedagogical and…

  17. High fertility and development in Cameroon | Nana-Fabu | Journal of ...

    African Journals Online (AJOL)

    High fertility and development in Cameroon. ... Journal of Social Development in Africa ... Many scholars of development, in sub Saharan Africa especially, have come to perceive increases in the African population as a threat to what is an already precarious balance between people and scarce natural resources, as well as ...

  18. 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

  19. Identification of three Me/oidogyne species from Cameroon by the ...

    African Journals Online (AJOL)

    A study was conducted to identify some Cameroonian Mefoidogyne species by the polymerase chain reaction (PCR). Meloidogyne isolates from various host crops in fifteen localities of the South West, West, and North West Provinces of Cameroon, were cultured on susceptible tomato in a greenhouse in Munster, Germany.

  20. Floodplain rehabilitation in Far North Cameroon: expected impact on bird life

    NARCIS (Netherlands)

    Scholte, P.; Kort, de S.; Weerd, van M.

    2000-01-01

    The Logone floodplain in the sahelo-Sudanian zone of Cameroon used to be a highly productive ecosystem. Perennial pastures and fish played a crucial role for fishermen, pastoralists and wildlife. The construction of an upstream dam reduced inundation causing widespread degradation Nonetheless,

  1. Contract farming and capital accumulation in Cameroon : the case of the CDC smallholder schemes

    NARCIS (Netherlands)

    Konings, P.J.J.; Geschiere, P.L.; Konings, P.J.J.

    1993-01-01

    Contract farming schemes associated with agro-industrial enterprises have been of a more limited scope in Cameroon than in several other Third World countries, and largely unsuccessful. The Cameroonian experience with contract farming therefore poses an interesting challenge to modernization

  2. 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…

  3. Risk Factors Associated With Epilepsy In A Rural Area In Cameroon ...

    African Journals Online (AJOL)

    Introduction An epileptic area with very high endemicity has been described in Bilomo, a village near Yaounde, the capital city of Cameroon. Purpose This study was carried out to determine some of the risk and precipitating factors associated with epilepsy in Bilomo. Patients and Methods This was part of a ...

  4. Learner Orientation through Professional Development of Teachers? Empirical Results from Cascade Training in Anglophone Cameroon

    Science.gov (United States)

    Lange, Sarah

    2014-01-01

    This paper examines the effects of a professional development programme on the attitudes towards the teaching and learning of teachers in the Anglophone part of Cameroon. The development programme combines a multiplier system with school-based in-service training. The research compares the effects that the training had on the attitudes of three…

  5. Journal of the Cameroon Academy of Sciences - Vol 9, No 1 (2011)

    African Journals Online (AJOL)

    Deformation history of the Yaounde Group in the Awae - Ayos area (Southern- Cameroon): Evidence for Pan-African thrust tectonics · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. JB Olinga, D Minyem, JE Mpesse, GE Ekodeck, 33-46 ...

  6. Religious revival in the Roman Catholic Church and the autochthony-allochthony conflict in Cameroon

    NARCIS (Netherlands)

    Konings, P.J.J.

    2003-01-01

    post-print versionThis article explores the reasons for, and the repercussions of, a virulent and protracted crisis in the South West Province of anglophone Cameroon during the 1990s caused by the emergence of a Pentecostalism-inspired revival movement within the Roman Catholic Church. The so-called

  7. 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

  8. Poverty and health among CDC plantation labourers in Cameroon: Perceptions, challenges and coping strategies

    NARCIS (Netherlands)

    Makoge, Valerie; Vaandrager, Lenneke; Maat, Harro; Koelen, Maria

    2017-01-01

    Creating better access to good quality healthcare for the poor is a major challenge to development. In this study, we examined inter-linkages between poverty and disease, referred to as poverty-related diseases (PRDs), by investigating how Cameroon Development Corporation (CDC) camp dwellers respond

  9. Violence against female sex workers in Cameroon: accounts of violence, harm reduction, and potential solutions.

    Science.gov (United States)

    Lim, Sahnah; Peitzmeier, Sarah; Cange, Charles; Papworth, Erin; LeBreton, Matthew; Tamoufe, Ubald; Kamla, Aristide; Billong, Serge; Fokam, Pamella; Njindam, Iliassou; Decker, Michele R; Sherman, Susan G; Baral, Stefan

    2015-03-01

    Female sex workers (FSWs) in Cameroon, and West Africa generally, suffer a disproportionate burden of HIV. Although violence against FSWs has been documented extensively in other parts of the world, data on violence from West African countries are lacking. The aim of this study was to qualitatively document violence and harm reduction strategies from the perspective of FSWs in Cameroon as well as to understand how experiences of violence may increase FSWs' HIV risk. FSWs from 7 major cities in Cameroon (Douala, Yaounde, Bamenda, Bertoua, Nagoundere, Kribi, and Bafoussam) were purposively recruited. Data from 31 in-depth interviews and 7 focus groups (n = 70; with some overlapping participants from in-depth interviews) conducted with these FSWs in 6 of these 7 cities (excluding Kribi) were analyzed using a grounded theory approach. Transcripts revealed 3 primary themes related to violence: (1) sources and types of violence, including sexual, physical, and financial violence perpetrated by clients and police, (2) harm reduction strategies, including screening clients and safe work locations, receipt of payment before sexual act, and formation of an informal security network, and (3) recommendations on structural changes to reduce violence that emphasized sex work decriminalization and increased police accountability. As in other parts of the world, violence against FSWs is pervasive in Cameroon. Interventions targeting violence and HIV must address the forms of violence cited locally by FSWs and can build on FSWs' existing strengths and harm reduction strategies. Structural changes are needed to ensure access to justice for this population.

  10. Laboratory diagnosis of malaria in the North West Region of Cameroon: analysis of limitations

    NARCIS (Netherlands)

    Ndofor, Eric; van Gool, Tom; Gillis, Henk

    2013-01-01

    Malaria is still rife and perennial in Cameroon despite remarkable progress in controlling the disease. About 95% of the country is malaria endemic. Prompt and accurate diagnosis of malaria may lead to improved patient care and reduced morbidity. This paper analyses limitations in malaria diagnosis

  11. 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

  12. 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

  13. Knowledge and utilization of edible mushrooms by local populations of the rain forest of South Cameroon

    NARCIS (Netherlands)

    Dijk, van J.F.W.; Onguene, N.A.; Kuyper, T.W.

    2003-01-01

    Indigenous knowledge of edible fungi and their utilization by local populations were investigated in southern Cameroon from 1996 to 1999. Some 100 participants from the major ethnic groups, comprising Bantu farmers and Bagyeli (Pygmy) hunter-gatherers, were interviewed. Mushroom usage by 30

  14. Prevalence and determinants of burnout syndrome among physicians in Cameroon: a research proposal.

    Science.gov (United States)

    Feteh, Vitalis Fambombi; Njim, Tsi; Nji, Miriam A M; Ayeah, Chia Mark; Sama, Carlson-Babila; Tianyi, Frank Leonel

    2017-10-25

    Burnout syndrome is a common psychological state, that may affect human healthcare providers due to their prolonged exposure to job stressors. Burnout can hinder optimal healthcare delivery. Hence this study aims to determine the prevalence and correlates of burnout syndrome amongst physicians in Cameroon. Specifically: (1) to determine the prevalence of burnout syndrome amongst Cameroonian doctors. (2) To identify potential determinants of burnout among Cameroonian doctors. (3) To compare the prevalence and determinants of burnout among specialist physicians and general practitioners in Cameroon. This cross-sectional study will include a minimum of 335 doctors working in five regions of Cameroon. Consenting physicians will be consecutively recruited and data on sociodemographic and work characteristics will be collected via a printed self-administered questionnaire and burnout will be assessed using the Maslach Burnout Inventory. Data will be analysed using Epi Info version 7 and a p value burnout syndrome. Physicians' mental health is largely neglected in developing countries like Cameroon. Data from this research will help inform practitioners on the magnitude of the problem and favour the development of policies that improve the mental health of care-providers.

  15. 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

  16. Local blacksmiths's activity in the west region of Cameroon and their ...

    African Journals Online (AJOL)

    As a result of the nature of pollutant and exhaustible of fossils energies, developed countries have made use of renewable energy sources to make effective their energy systems. To stow on that vision in Cameroon, the promotion of micro-hydroelectric powers plants (MHPP) is a priority and any contribution to its ease is ...

  17. 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.

  18. "Ask and you shall be given" : Pentecostalism and the economic crisis in Cameroon

    NARCIS (Netherlands)

    Akoko, R.M.

    2007-01-01

    Cameroon's economic crisis has led to widespread unemployment and poverty since the 1980s. Civil society organizations, including the churches, believe that bad governance is at the heart of the country's economic problems and are calling for the introduction of democratic institutions. However, a

  19. Novel Human Rotavirus Genotype G5P[7] from Child with Diarrhea, Cameroon

    Science.gov (United States)

    Geyer, Annelise; Banyai, Krisztian; Page, Nicola; Aminu, Maryam; Armah, George E.; Hull, Jennifer; Steele, Duncan A.; Glass, Roger I.; Gentsch, Jon R.

    2009-01-01

    We report characterization of a genotype G5P[7] human rotavirus (HRV) from a child in Cameroon who had diarrhea. Sequencing of all 11 gene segments showed similarities to >5 genes each from porcine and human rotaviruses. This G5P[7] strain exemplifies the importance of heterologous animal rotaviruses in generating HRV genetic diversity through reassortment. PMID:19116059

  20. ‘The vagina does not talk’: conception concealed or deliberately disclosed in Eastern Cameroon

    NARCIS (Netherlands)

    van der Sijpt, E.

    2012-01-01

    In the East Province of Cameroon, respectable womanhood has long been intrinsically related to ethics of production and reproduction: women attain social standing through productive work in the fields and through the reproduction of children - preferably within a marital setting. Yet, in the face of

  1. Diet selection and density estimates of forest buffalo in Campo-Ma'an National Park, Cameroon

    NARCIS (Netherlands)

    Bekhuis, P.; Jong, de C.B.; Prins, H.H.T.

    2008-01-01

    We studied diet selection and density of forest buffalo in the Campo Ma'an National Park of southern Cameroon. The buffalo's diet in this rainforest comprised 43% grass, including 15%Leptochloa caerulecens. Other species eaten were non-graminoid monocots (21.3%), mainly Commelinaceae (18.2%),

  2. 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.

  3. Io Eclipse/Volcanic Eruption

    Science.gov (United States)

    1997-01-01

    This image was acquired while Io was in eclipse (in Jupiter's shadow) during Galileo's eighth orbit, and reveals several dynamic processes. The most intense features are red, while glows of lesser intensity are yellow or green, and very faint glows appear blue in this color-coded image. The small red or yellow spots mark the sites of high-temperature magma erupting onto the surface in lava flows or lava lakes.This image reveals a field of bright spots near Io's sub-Jupiter point (right-hand side of image). The sub-Jupiter hemisphere always faces Jupiter just as the Moon's nearside always faces Earth. There are extended diffuse glows on the equatorial limbs or edges of the planet (right and left sides). The glow on the left is over the active volcanic plume Prometheus, but whereas Prometheus appears to be 75 kilometers (46.6 miles) high in reflected light, here the diffuse glow extends about 800 kilometers (497 miles) from Io's limb. This extended glow indicates that gas or small particles reach much greater heights than the dense inner plume. The diffuse glow on the right side reaches a height of 400 kilometers (249 miles), and includes a prominence with a plume-like shape. However, no volcanic plume has been seen at this location in reflected light. This type of observation is revealing the relationships between Io's volcanism, atmosphere and exosphere.Taken on May 6, 1997, north is toward the top. The image was taken with the clear filter of the solid state imaging (CCD) system on NASA's Galileo spacecraft at a range of 1.8 million kilometers (1.1 million miles).The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational

  4. 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

  5. Assessing Mesoscale Volcanic Aviation Hazards using ASTER

    Science.gov (United States)

    Pieri, D.; Gubbels, T.; Hufford, G.; Olsson, P.; Realmuto, V.

    2006-12-01

    The Advanced Spaceborne Thermal Emission and Reflection (ASTER) imager onboard the NASA Terra Spacecraft is a joint project of the Japanese Ministry for Economy, Trade, and Industry (METI) and NASA. ASTER has acquired over one million multi-spectral 60km by 60 km images of the earth over the last six years. It consists of three sub-instruments: (a) a four channel VNIR (0.52-0.86um) imager with a spatial resolution of 15m/pixel, including three nadir-viewing bands (1N, 2N, 3N) and one repeated rear-viewing band (3B) for stereo-photogrammetric terrain reconstruction (8-12m vertical resolution); (b) a SWIR (1.6-2.43um) imager with six bands at 30m/pixel; and (c) a TIR (8.125-11.65um) instrument with five bands at 90m/pixel. Returned data are processed in Japan at the Earth Remote Sensing Data Analysis Center (ERSDAC) and at the Land Processes Distributed Active Archive Center (LP DAAC), located at the USGS Center for Earth Resource Observation and Science (EROS) in Sioux Falls, South Dakota. Within the ASTER Project, the JPL Volcano Data Acquisition and Analyses System (VDAAS) houses over 60,000 ASTER volcano images of 1542 volcanoes worldwide and will be accessible for downloads by the general public and on-line image analyses by researchers in early 2007. VDAAS multi-spectral thermal infrared (TIR) de-correlation stretch products are optimized for volcanic ash detection and have a spatial resolution of 90m/pixel. Digital elevation models (DEM) stereo-photogrammetrically derived from ASTER Band 3B/3N data are also available within VDAAS at 15 and 30m/pixel horizontal resolution. Thus, ASTER visible, IR, and DEM data at 15-100m/pixel resolution within VDAAS can be combined to provide useful boundary conditions on local volcanic eruption plume location, composition, and altitude, as well as on topography of underlying terrain. During and after eruptions, low- altitude winds and ash transport can be affected by topography, and other orographic thermal and water vapor

  6. Functioning and disability in recent research from Cameroon: a narrative synthesis.

    Science.gov (United States)

    Ray, Minal; Wallace, Lorena; Mbuagbaw, Lawrence; Cockburn, Lynn

    2017-01-01

    People living with disabilities in Cameroon face many barriers to daily functioning and social participation. However, there is limited research on disabilities and their impact. We sought to examine the research related to disability from Cameroon. We conducted a systematic review, bibliometric analysis, and narrative synthesis of research related to disability, functioning, and social participation from Cameroon published during 2005-2014. The articles were screened in duplicate to identify articles addressing impacts of disability on functioning. Disability was contextualized using the International Classification of Functioning, Disability and Health (ICF) framework. Data were analyzed narratively per identified themes using an inductive data-driven approach. A total of 46 studies were included following full-text review of which 36 addressed non-communicable diseases and conditions, 7 addressed infectious diseases and 3 addressed neglected tropical diseases. Among ICF Activity and Participation Restrictions, work and employment was the highest reported category (19 studies), followed by intimate relationships (14 studies), and looking after one's health (8 studies). Among ICF Environmental Factors, societal attitudes were the highest reported category (21 studies), followed by health services, systems and policies (14 studies) and support and relationships (11 studies). Among other common themes, knowledge and awareness was the highest reported category (22 studies), closely followed by traditional beliefs (20 studies) and financial barriers (9 studies). There is a small body of primary research from Cameroon on disability. The main themes related to disability are stigma, limited knowledge and awareness, poor quality of care and hindered employment opportunities. Further efforts are required to investigate the complexities of living with a disability in Cameroon and strategies to enhance adequate participation in activities of daily life.

  7. Lessons for REDD+ from Cameroon's past forestry law reform: a political economy analysis

    Directory of Open Access Journals (Sweden)

    Guy Patrice Dkamela

    2014-09-01

    Full Text Available Reducing emissions from deforestation and forest degradation and enhancing forest carbon stocks (REDD+ is gaining traction in Cameroon. However, given the deep-rooted trans-sectoral drivers of forest loss, enforcing REDD+ policies will require major policy change and reform both within and beyond the forestry sector. In this paper, we view the REDD+ policy arena in Cameroon within a political economy framework and conduct policy network analysis to explore the factors that will enable or hinder efforts to implement the broad policy change required to realize REDD+. As the REDD+ context is shaped by the history of Cameroon's forestry sector, we draw lessons for REDD+ from the forestry law reform undertaken in 1994. We focus our analysis on three factors considered necessary for REDD+ success: (i autonomy of the nation state from interests behind deforestation and forest degradation, (ii national ownership over reform processes, and (iii inclusiveness of policy processes. We find that the REDD+ policy process in Cameroon is repeating the weaknesses of the earlier forestry law reform, as seen in the minimal ownership of REDD+ by national actor groups and low inclusiveness among domestic actors at both national and local levels, as well as the absence of a national coalition for REDD+. Furthermore, politics and private agendas are compromising state agencies' autonomy in making decisions about forest resources. Our findings suggest that responses to these weaknesses, as well as to inconsistencies between sectoral policies and to competition over forest resources, will determine whether REDD+ can induce change within and beyond Cameroon's forestry sector.

  8. 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.

  9. Volcanic caves of East Africa - an overview

    Directory of Open Access Journals (Sweden)

    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.

  10. Low Birth Weight in Perinatally HIV-Exposed Uninfected Infants: Observations in Urban Settings in Cameroon

    Science.gov (United States)

    Sofeu, Casimir Ledoux; Warszawski, Josiane; Ateba Ndongo, Francis; Penda, Ida Calixte; Tetang Ndiang, Suzie; Guemkam, Georgette; Makwet, Nicaise; Owona, Félicité; Kfutwah, Anfumbom; Tchendjou, Patrice; Texier, Gaëtan; Tchuente, Maurice; Faye, Albert; Tejiokem, Mathurin Cyrille

    2014-01-01

    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

  11. Geology of Newberry National Volcanic Monument, Oregon, USA

    Science.gov (United States)

    Donnelly-Nolan, J. M.; Jensen, R. A.; Robinson, J. E.

    2014-12-01

    Volcanic geology is the dominant theme at Newberry National Volcanic Monument in central Oregon. Established almost 25 years ago, the NNVM (like the Mt. St. Helens National Volcanic Monument) is managed by the U.S. Forest Service. The monument encompasses some 90 square miles in Deschutes National Forest of the 1200-sq-mi Newberry Volcano, including the 4x5 mi scenic central caldera and the volcano's youngest lava flow, the 1300-yr-old Big Obsidian Flow. The seismically-monitored Newberry Volcano is considered by the USGS to be a very high threat volcano, with the potential to impact adjacent populations in Bend, Sunriver, and LaPine and damage infrastructure including highways, railroads, and power lines. Unspectacular from a distance, the broad shield shape of Newberry Volcano hides the abundance and youthfulness of volcanic activity. Included in NNVM are 7-ka basalt to andesite lavas of the Northwest Rift Zone (NWRZ) that erupted from spatter and cinder cones over a N-S distance of 20 miles and temporarily blocked the flow of the adjacent Deschutes River. These well-exposed lavas are post-Mazama in age, having erupted after a blanket of ash and pumice was deposited on the volcano when Mt. Mazama erupted at 7.7 ka to form Crater Lake. Images from lidar data obtained in 2011 clearly display the post-Mazama lavas, which not only are unmantled by the tephra, but also lack the thick forest that has grown in the tephra further obscuring many of the youthful volcanic features across this massive rear-arc Cascades volcano. NNVM features interpretive trails at the Big Obsidian Flow in the caldera and at Lava Cast Forest and Lava Butte flow along the NWRZ. Also within the monument are two of the premier drivable viewpoints in Oregon, on Lava Butte and at the 7984-ft top of Paulina Peak on the rim of the caldera. On a clear day, views from Paulina Peak encompass much of the High Cascades, extending from Mt. Shasta in California to Mt. Adams in Washington.

  12. Active Volcanic Plumes on Io

    Science.gov (United States)

    1997-01-01

    This color image, acquired during Galileo's ninth orbit around Jupiter, shows two volcanic plumes on Io. One plume was captured on the bright limb or edge of the moon (see inset at upper right), erupting over a caldera (volcanic depression) named Pillan Patera after a South American god of thunder, fire and volcanoes. The plume seen by Galileo is 140 kilometers (86 miles) high and was also detected by the Hubble Space Telescope. The Galileo spacecraft will pass almost directly over Pillan Patera in 1999 at a range of only 600 kilometers (373 miles).The second plume, seen near the terminator (boundary between day and night), is called Prometheus after the Greek fire god (see inset at lower right). The shadow of the 75-kilometer (45- mile) high airborne plume can be seen extending to the right of the eruption vent. The vent is near the center of the bright and dark rings. Plumes on Io have a blue color, so the plume shadow is reddish. The Prometheus plume can be seen in every Galileo image with the appropriate geometry, as well as every such Voyager image acquired in 1979. It is possible that this plume has been continuously active for more than 18 years. In contrast, a plume has never been seen at Pillan Patera prior to the recent Galileo and Hubble Space Telescope images.North is toward the top of the picture. The resolution is about 6 kilometers (3.7 miles) per picture element. This composite uses images taken with the green, violet and near infrared filters of the solid state imaging (CCD) system on NASA's Galileo spacecraft. The images were obtained on June 28, 1997, at a range of more than 600,000 kilometers (372,000 miles).The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http

  13. 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...

  14. Palaeoclimate: Volcanism caused ancient global warming

    Science.gov (United States)

    Meissner, Katrin J.; Bralower, Timothy J.

    2017-08-01

    A study confirms that volcanism set off one of Earth's fastest global-warming events. But the release of greenhouse gases was slow enough for negative feedbacks to mitigate impacts such as ocean acidification. See Letter p.573

  15. Submarine silicic volcanism: Processes and products

    Digital Repository Service at National Institute of Oceanography (India)

    Kalangutkar, N.G.; Iyer, S.D.

    The occurrence of submarine silicic volcanics is rare at the mid-oceanic ridges, abyssal depths, seamounts and fracture zones. Hydrothermal processes are active in submarine silicic environments and are associated with host ores of Cu, Au, Ag, Pb...

  16. [Contribution of the Institut de Formation et de Recherche Demographiques (IFORD) to population activities in Cameroon].

    Science.gov (United States)

    Ngatchou, R D; Mbida, O

    1984-01-01

    The Institute for Demographic Training and Research (IFORD) has contributed more to demographic knowledge in Cameroon than in other countries because of its location within Cameroon. Training in demography at IFORD had 3 phases: classic training, intended to provide students with a solid background in demography including data collection and interpretation and knowledge of population interactions with social and economic development; initiation of research, in which graduates in demography spend a year working on projects at the Institute; and perfecting of research on particular topics by groups of established professionals in sessions lasting up to 4 weeks. 38 Cameroonian demographers have been trained by IFORD since 1974, 4 have received initial research training, and 2 or 3 have been included in each short course. Each year since 1973, IFORD has organized a census or survey in the medium sized towns of Cameroon to provide data as well as training opportunities for future demographers. Most of the surveys have been analyzed and the results published. The publication section of IFORD, created in January 1979, produces 4 series of publications: a liaison bulletin of African demography, Annals of IFORD, notes and documents, and pedagogic documents. 5 issues of the Annals and 2 of the notes and documents have dealt with Cameroon and others are due to appear shortly. A survey on levels and differentials of infant and child mortality is the most important demographic research undertaken by IFORD in Cameroon to date. Each of the 10,000 newborns included was followed at home in 7 visits between 1978-81. Evaluations of sources of demographic data have also been done. IFORD publications containing research findings for Cameroon on topics including urban growth, rural population and agrarian problems, monographs on national and regional populations, mortality, fertility, the active population and employment status, the school age population, and methodologic studies, are

  17. Volcanic rock properties control sector collapse events

    Science.gov (United States)

    Hughes, Amy; Kendrick, Jackie; Lavallée, Yan; Hornby, Adrian; Di Toro, Giulio

    2017-04-01

    Volcanoes constructed by superimposed layers of varying volcanic materials are inherently unstable structures. The heterogeneity of weak and strong layers consisting of ash, tephra and lavas, each with varying coherencies, porosities, crystallinities, glass content and ultimately, strength, can promote volcanic flank and sector collapses. These volcanoes often exist in areas with complex regional tectonics adding to instability caused by heterogeneity, flank overburden, magma movement and emplacement in addition to hydrothermal alteration and anomalous geothermal gradients. Recent studies conducted on the faulting properties of volcanic rocks at variable slip rates show the rate-weakening dependence of the friction coefficients (up to 90% reduction)[1], caused by a wide range of factors such as the generation of gouge and frictional melt lubrication [2]. Experimental data from experiments conducted on volcanic products suggests that frictional melt occurs at slip rates similar to those of plug flow in volcanic conduits [1] and the bases of mass material movements such as debris avalanches from volcanic flanks [3]. In volcanic rock, the generation of frictional heat may prompt the remobilisation of interstitial glass below melting temperatures due to passing of the glass transition temperature at ˜650-750 ˚C [4]. In addition, the crushing of pores in high porosity samples can lead to increased comminution and strain localisation along slip surfaces. Here we present the results of friction tests on both high density, glass rich samples from Santaguito (Guatemala) and synthetic glass samples with varying porosities (0-25%) to better understand frictional properties underlying volcanic collapse events. 1. Kendrick, J.E., et al., Extreme frictional processes in the volcanic conduit of Mount St. Helens (USA) during the 2004-2008 eruption. J. Structural Geology, 2012. 2. Di Toro, G., et al., Fault lubrication during earthquakes. Nature, 2011. 471(7339): p. 494-498. 3

  18. Volcanism and associated hazards: the Andean perspective

    Directory of Open Access Journals (Sweden)

    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

  19. Shape measurements of volcanic particles by CAMSIZER

    OpenAIRE

    Lo Castro, Maria Deborah; Andronico, Daniele; Nunnari, Giuseppe; Spata, Alessandro; Torrisi, Alessio

    2009-01-01

    The shape of volcanic particles is an important parameter holding information related to physical and geochemical processes. The study of particle shape may help improving knowledge on the main eruptive processes (fragmentation, transport and sedimentation) during explosive activity. In general, volcanic ash is formed by different components, namely juvenile, lithic and crystal particles, each one characterized by peculiar morphology. Moreover, quantifying the shape of pyroclasts is needed by...

  20. 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

  1. Medical effects of volcanic eruptions

    Science.gov (United States)

    Baxter, Peter J.

    1990-09-01

    Excluding famine and tsunamis, most deaths in volcanic eruptions have been from pyroclastic flows and surges (nuées ardentes) and wet debris flows (lahars). Information on the causes of death and injury in eruptions is sparse but the available literature is summarised for the benefit of volcanologists and emergency planners. In nuées, thermal injury may be at least as important as asphyxia in causing immediate deaths. The high temperature of the gases and entrained particles readily causes severe burns to the skin and the air passages and the presence of both types of injury in an individual may combine to increase the delayed mortality risk from respiratory complications or from infection of burns. Trauma from missiles or body displacement is also common, but the role of asphyxiant or irritant gases, and steam, remains unclear. The ratio of dead: injured is much higher than in other natural disasters. At the periphery of a nuée being protected inside buildings which remain intact appears to greatly increase the chances of survival. In lahars, infected wounds and crush injury are the main delayed causes of death, and the scope for preventive measures, other than evacuation, is small. The evidence from Mount St. Helens, 1980, and other major eruptions indicates that, although mortality is high within the main zone of devastation and in the open, emergency planning should concentrate on the periphery of a nuée where preventive measures are feasible and could save many lives in densely populated areas.

  2. Geosphere-biosphere interactions in bio-activity volcanic lakes: evidences from Hule and Rìo 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

  3. 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.

  4. 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

  5. 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.

  6. Cooperia pectinata and C. punctata, parasites of the abomasum of cattle in northern Cameroon (Central Africa).

    Science.gov (United States)

    Chollet, J Y; Jacquiet, P; Cardinale, E; Ndamkou-Ndamkou, C; Diop, C; Thiam, A; Dorchies, P

    2000-02-29

    Cooperia pectinata Ransom, 1907 and C. punctata von Linstow, 1907 are common trichostrongyles of zebu cattle in Africa. Their intestinal localization within the digestive tract is considered by many authors to be exclusive. Nevertheless, some limited surveys in Malagasy, Mauritania, The Gambia and Cameroon reported the presence of both Cooperia species in the abomasum. The present survey was carried out in a slaughterhouse of northern Cameroon on 17 zebu cattle and confirms the infection of the small intestine and the abomasum by the two species within the total number of cattle examined. Abomasal infections especially with Cooperia punctata were heavier than those in the intestine. Due to the movements of herdbreeders in Central Africa, and to the preliminary results obtained in Mauritania, The Gambia, Burkina Faso and Malagasy, abomasal localization of C. pectinata and C. punctata may be encountered in very large areas of Africa, and that cooperiosis may contribute together with Haemonchus species to the digestive disorders involving the abomasum.

  7. A low proportion of HBeAg among HBsAg-positive pregnant women with known HIV status could suggest low perinatal transmission of HBV in Cameroon

    Directory of Open Access Journals (Sweden)

    Kfutwah Anfumbom KW

    2012-03-01

    Full Text Available Abstract Background Transmission of hepatitis B virus (HBV from HBV-positive mothers to their infants is common and usually occurs when the mother is hepatitis B e antigen (HBeAg positive and/or has a high HBV DNA load. In this study, we determined the prevalence of hepatitis B surface antigen (HBsAg and HBeAg among pregnant women with known HIV status. Findings A total of 650 pregnant women with a mean age of 26.2 years including 301 HIV-positives and 349 HIV-negatives were screened for HBsAg (Monolisa AgHBs Plus Biorad, France. Among the HBsAg-positives, HBeAg and anti-HBe were tested (Monolisa Ag HBe Plus Biorad, France. Overall, 51 (7.85% were positive for HBsAg. The prevalence of HBsAg was not statistically different between HIV-positive and HIV-negative pregnant women [28/301 (9.3% vs 23/349 (6.59%; p = 0.2]. None of the 45 HBsAg-positive samples was reactive for HBeAg. Conclusions Our study indicates a high prevalence of HBsAg with very low proportion of HBeAg in Cameroonian pregnant women. Since perinatal transmission of HBV is mostly effective when the mother is also HBeAg-positive, our data could suggest that perinatal transmissions play a minor role in HBV prevalence in Cameroon. In line with previous African studies, these findings further suggests that horizontal transmission could be the most common mechanism of HBV infections in Cameroon.

  8. Plant biodiversity and vegetation structure in traditional cocoa forest gardens in southern Cameroon under different management

    OpenAIRE

    Bisseleua, D. Hervé B.; Vidal, Stefan

    2007-01-01

    Floristic surveys were performed in 17 traditional cocoa forest gardens under different management regimes in the humid forest area of southern Cameroon, to assess the impact of intensification on plant biodiversity. This impact was evaluated by analyzing species richness, vegetation structure, carbon sequestration and above ground biomass. We hypothesize that: (a) plant (tree and herbs) species richness is negatively correlated to management intensity and (b) vegetational density predictably...

  9. Genetic structure of the tiger mosquito, Aedes albopictus, in Cameroon (Central Africa.

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    Basile Kamgang

    Full Text Available BACKGROUND: Aedes albopictus (Skuse, 1884 (Diptera: Culicidae, a mosquito native to Asia, has recently invaded all five continents. In Central Africa it was first reported in the early 2000s, and has since been implicated in the emergence of arboviruses such as dengue and chikungunya in this region. Recent genetic studies of invasive species have shown that multiple introductions are a key factor for successful expansion in new areas. As a result, phenotypic characters such as vector competence and insecticide susceptibility may vary within invasive pest species, potentially affecting vector efficiency and pest management. Here we assessed the genetic variability and population genetics of Ae. albopictus isolates in Cameroon (Central Africa, thereby deducing their likely geographic origin. METHODS AND RESULTS: Mosquitoes were sampled in 2007 in 12 localities in southern Cameroon and analyzed for polymorphism at six microsatellite loci and in two mitochondrial DNA regions (ND5 and COI. All the microsatellite markers were successfully amplified and were polymorphic, showing moderate genetic structureamong geographic populations (F(ST  = 0.068, P < 0.0001. Analysis of mtDNA sequences revealed four haplotypes each for the COI and ND5 genes, with a dominant haplotype shared by all Cameroonian samples. The weak genetic variation estimated from the mtDNA genes is consistent with the recent arrival of Ae. albopictus in Cameroon. Phylogeographic analysis based on COI polymorphism indicated that Ae. albopictus populations from Cameroon are related to tropical rather than temperate or subtropical outgroups. CONCLUSION: The moderate genetic diversity observed among Cameroonian Ae. albopictus isolates is in keeping with recent introduction and spread in this country. The genetic structure of natural populations points to multiple introductions from tropical regions.

  10. Developing effective chronic disease interventions in Africa: insights from Ghana and Cameroon

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    Boynton Petra

    2010-04-01

    Full Text Available Abstract Background Africa faces an urgent but 'neglected epidemic' of chronic disease. In some countries stroke, hypertension, diabetes and cancers cause a greater number of adult medical admissions and deaths compared to communicable diseases such as HIV/AIDS or tuberculosis. Experts propose a three-pronged solution consisting of epidemiological surveillance, primary prevention and secondary prevention. In addition, interventions must be implemented through 'multifaceted multi-institutional' strategies that make efficient use of limited economic and human resources. Epidemiological surveillance has been prioritised over primary and secondary prevention. We discuss the challenge of developing effective primary and secondary prevention to tackle Africa's chronic disease epidemic through in-depth case studies of Ghanaian and Cameroonian responses. Methods A review of chronic disease research, interventions and policy in Ghana and Cameroon instructed by an applied psychology conceptual framework. Data included published research and grey literature, health policy initiatives and reports, and available information on lay community responses to chronic diseases. Results There are fundamental differences between Ghana and Cameroon in terms of 'multi-institutional and multi-faceted responses' to chronic diseases. Ghana does not have a chronic disease policy but has a national health insurance policy that covers drug treatment of some chronic diseases, a culture of patient advocacy for a broad range of chronic conditions and mass media involvement in chronic disease education. Cameroon has a policy on diabetes and hypertension, has established diabetes clinics across the country and provided training to health workers to improve treatment and education, but lacks community and media engagement. In both countries churches provide public education on major chronic diseases. Neither country has conducted systematic evaluation of the impact of

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

    OpenAIRE

    Kouam Luc; Wiysonge Charles; Fomulu Nelson; Ngassa Pius; Kongnyuy Eugene J; Doh Anderson S

    2007-01-01

    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 t...

  12. Wild Food, Prices, Diets and Development: Sustainability and Food Security in Urban Cameroon

    OpenAIRE

    Lauren Q. Sneyd

    2013-01-01

    This article analyses wild food consumption in urban areas of Cameroon. Building upon findings from Cameroon’s Comprehensive Food Security and Vulnerability Analysis (CFSVA) this case study presents empirical data collected from 371 household and market surveys in Cameroonian cities. It employs the UN Special Rapporteur on the Right to Food’s framework for understanding challenges related to the availability, accessibility, and adequacy of food. The survey data suggest that many wild/traditio...

  13. [Fertility and mortality in the urban agglomeration of Banyo (Cameroon): the influence of venereal diseases].

    Science.gov (United States)

    Hurault, J

    1983-01-01

    The demographic situation in the city of Banyo, Cameroon, is described for the period 1952-1976 using survey and census data. This city was characterized by a large slave population, particularly in the nineteenth century, and slavery remained common up to the 1960s. The consequences of slavery, including disruption of family life, concubinage, and high rates of venereal disease, are noted. Fertility and mortality differences among the slave and free populations are analyzed by sex. (summary in ENG, SPA)

  14. 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...neighbors. Chad , for example, has emerged in recent weeks as a key player in the effort to counter Boko Haram . In early February, Chadian troops entered...Cameroon, Chad , and Niger in their fight to defeat Boko Haram . __________  This work was published by the Center for Strategic Studies (CSS) at the CNA

  15. Forest eternal? Endemic butterflies of the Bamenda highlands, Cameroon, avoid close-canopy forest

    Czech Academy of Sciences Publication Activity Database

    Tropek, Robert; Konvička, M.

    2010-01-01

    Roč. 48, č. 2 (2010), s. 428-437 ISSN 0141-6707 R&D Projects: GA ČR GD206/08/H044 Grant - others:Ministry of Agriculture and Rural Development of the Republic of Cameroon(CM) 014125; AV ČR(CZ) IAA601410709 Program:IA Institutional research plan: CEZ:AV0Z50070508 Keywords : afromontane landscape * conservation * Lepidoptera Subject RIV: EH - Ecology, Behaviour Impact factor: 0.778, year: 2010

  16. Fatal monomorphic ventricular tachycardia in a semi-urban setting in Cameroon: a case report

    OpenAIRE

    Nkoke, Clovis; Luchuo, Engelbert Bain; Dikoume, Laetitia

    2017-01-01

    Background Ventricular tachycardia is a life threatening cardiac arrhythmia. It needs management with defibrillation, without which, immediate death may occur. Case presentation A 66?year old black African patient with a 2?year history of hypertension was admitted to the emergency department of the Buea Regional hospital, a semi-urban setting in Cameroon, after presenting with syncope while in church. The wife described a similar episode 2?weeks prior without any further evaluation. Upon arri...

  17. 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

    2016-10-01

    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. 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. 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. 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.

  18. Weight gain of steers on pastures of cameroon grass and braquiarão grass

    Directory of Open Access Journals (Sweden)

    Cláudia de Paula Rezende

    2015-07-01

    Full Text Available We evaluate pastures formed of Pennisetum purpureum cv.cameroon and Urochloa brizantha.cv. Marandu aiming at greater live weight gains per animal and per hectare. The animals were crossbred male half blood Tabapuã/Nellore live weight of 280 kg (9.3 kilos. Each grass was submitted to four stocking rates in a rotated grazing system with three days of grazing and 36 days of rest, resulting in a 39 days grazing cycle. In the summer the stocking rates were 2.64, 3.49, 4.34 and 5.09 UA/ha in and winter the rates were 164, 2.38, 3.26 and 3.89 UA/ha. In summer, the stocking rate of 4.34 UA/ha enabled best combination between weight gain per animal and per area with daily average gains of 0.560kg/animal and 2.99 kg/ha on cameroon grass and of 0.505 kg/animal and 2.79 kg/ha for braquiarão grass. However, in winter, the stocking rate of 3.26 UA/ha was the one which enabled greatest animal yield with daily average gains of 0.670kg/animal and 2.86 kg/ha on cameroon grass and 0.503 kg/animal and 2.10kg/ha on braquiarão grass. The weight gain per animal and per area is influenced by stocking rate. The cameroon grass provides greater weight than grass braquiarão gains, both animal as per area, in both rainy and dry seasons.

  19. Epidemiology of rotavirus diarrhea in children under 5 years in Northern Cameroon.

    Science.gov (United States)

    Ndze, Valentine Ngum; Akum, Achidi Eric; Kamga, Gonsu Hortense; Enjema, Lyonga Emilia; Esona, Mathew Dioh; Banyai, Krisztian; Therese, Obama Abena Marie

    2012-01-01

    Rotavirus still remains the major cause of diarrhea in children below 5 years. No data on rotavirus epidemiology is available in the Northern regions of Cameroon. We aimed to determine the prevalence of group A rotavirus (RVA) in children below 5 years with diarrhea in two regions of Northern Cameroon (North West and Far North Regions) so as to improve our knowledge on the burden of rotavirus disease for imminent introduction of a rotavirus vaccine. Stool samples were collected during 2010 and 2011 from 390 children below 5 years presenting with diarrhea in four hospitals in Northern Cameroon and were screened for rotavirus group A by reverse transcription-polymerase chain reaction. This study revealed that 42.8% of the children below 5 years had group A rotavirus infection, 46.5% in the Far North region while the North West had a prevalence of 33.9%. Of the 252 hospitalized and the 138 outpatient children, 124(49.2%) and 43(31.2%) (P=0.00085), respectively, were positive for group A rotavirus. Children below 24 months were most affected (44.7%), while the age group 49-60 months had the lowest prevalence (25%). The RVA prevalence was 44.6% in the urban and 28.9% in the rural settings of our study. It was observed that the proportion of children with diarrhea who had rotavirus accompanied with fever and vomiting in the outpatient group and inpatient group were 13.0% and 28.6% respectively, P=0.03. This study showed high incidence of rotavirus infection especially among hospitalized children in Northern Cameroon, suggesting that rotavirus is a major cause of childhood morbidity and mortality in this area.

  20. Perceptions Regarding HIV/AIDS and Risky Behaviours Among Prison Inmates in Southwest Region of Cameroon

    OpenAIRE

    Tarkang EE; Pietra V; Adam A; Fusheini A; Kweku M

    2016-01-01

    Prisoners are at exceptional risk of infection with HIV because of the association of injection drug use, tattooing, sex between men and unprotected sexual intercourse with incarceration. This study described the perceptions regarding HIV/ AIDS and risky behaviours among prison inmates in Kumba in the Southwest region of Cameroon.This was a cross sectional study, conducted among 232 male prison inmates in Kumba, in December 2015. Data were collected using a structured pretested questionnaire,...

  1. On the Role of Climate Forcing by Volcanic Sulphate and Volcanic Ash

    Directory of Open Access Journals (Sweden)

    Baerbel Langmann

    2014-01-01

    Full Text Available There is overall agreement that volcanic sulphate aerosols in the stratosphere can reduce solar radiation reaching the earth’s surface for years, thereby reducing surface temperatures, affecting global circulation patterns and generally the global climate system. However, the response of the climate system after large volcanic eruptions is not fully understood and global climate models have difficulties to reproduce the observed variability of the earth system after large volcanic eruptions until now. For geological timescales, it has been suggested that, in addition to the stratospheric climate forcing by volcanic sulphate aerosols, volcanic ash affects climate by modifying the global carbon cycle through iron fertilising the surface ocean and stimulating phytoplankton growth. This process has recently also been observed after the eruption of the volcano Kasatochi on the Aleutian Islands in summer 2008. To trigger future research on the effect of volcanic ash on the climate system via ocean iron fertilisation, this review paper describes the formation processes and atmospheric life cycles of volcanic sulphate and volcanic ash, contrasts their impact on climate, and emphasises current limitations in our understanding.

  2. Volcanic Supersites as cross-disciplinary laboratories

    Science.gov (United States)

    Provenzale, Antonello; Beierkuhnlein, Carl; Giamberini, Mariasilvia; Pennisi, Maddalena; Puglisi, Giuseppe

    2017-04-01

    Volcanic Supersites, defined in the frame of the GEO-GSNL Initiative, are usually considered mainly for their geohazard and geological characteristics. However, volcanoes are extremely challenging areas from many other points of view, including environmental and climatic properties, ecosystems, hydrology, soil properties and biogeochemical cycling. Possibly, volcanoes are closer to early Earth conditions than most other types of environment. During FP7, EC effectively fostered the implementation of the European volcano Supersites (Mt. Etna, Campi Flegrei/Vesuvius and Iceland) through the MED-SUV and FUTUREVOLC projects. Currently, the large H2020 project ECOPOTENTIAL (2015-2019, 47 partners, http://www.ecopotential-project.eu/) contributes to GEO/GEOSS and to the GEO ECO Initiative, and it is devoted to making best use of remote sensing and in situ data to improve future ecosystem benefits, focusing on a network of Protected Areas of international relevance. In ECOPOTENTIAL, remote sensing and in situ data are collected, processed and used for a better understanding of the ecosystem dynamics, analysing and modelling the effects of global changes on ecosystem functions and services, over an array of different ecosystem types, including mountain, marine, coastal, arid and semi-arid ecosystems, and also areas of volcanic origin such as the Canary and La Reunion Islands. Here, we propose to extend the network of the ECOPOTENTIAL project to include active Volcanic Supersites, such as Mount Etna and other volcanic Protected Areas, and we discuss how they can be included in the framework of the ECOPOTENTIAL workflow. A coordinated and cross-disciplinary set of studies at these sites should include geological, biological, ecological, biogeochemical, climatic and biogeographical aspects, as well as their relationship with the antropogenic impact on the environment, and aim at the global analysis of the volcanic Earth Critical Zone - namely, the upper layer of the Earth

  3. Pneumocystis jirovecii colonisation in HIV-positive and HIV-negative subjects in Cameroon.

    Science.gov (United States)

    Riebold, D; Enoh, D O; Kinge, T N; Akam, W; Bumah, M K; Russow, K; Klammt, S; Loebermann, M; Fritzsche, C; Eyong, J E; Eppel, G; Kundt, G; Hemmer, C J; Reisinger, E C

    2014-06-01

    To determine the prevalence of Pneumocystis pneumonia (PCP), a major opportunistic infection in AIDS patients in Europe and the USA, in Cameroon. Induced sputum samples from 237 patients without pulmonary symptoms (126 HIV-positive and 111 HIV-negative outpatients) treated at a regional hospital in Cameroon were examined for the prevalence of Pneumocystis jirovecii by specific nested polymerase chain reaction (nPCR) and staining methods. CD4 counts and the history of antiretroviral therapy of the subjects were obtained through the ESOPE database system. Seventy-five of 237 study participants (31.6%) were colonised with Pneumocystis, but none showed active PCP. The Pneumocystis colonisation rate in HIV-positive subjects was more than double that of HIV-negative subjects (42.9% vs. 18.9%, P 500 cells/μl were colonised at a rate of 20.0%, subjects with CD4 counts between 200 and 500 cells/μl of 42.5%, and subjects with CD4 counts <200 cells/μl of 57.1%. Colonisation with Pneumocystis in Cameroon seems to be comparable to rates found in Western Europe. Prophylactic and therapeutic measures against Pneumocystis should be taken into account in HIV care in western Africa. © 2014 John Wiley & Sons Ltd.

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

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    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.

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

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    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.

  6. Pattern and clinical aspects of congenital heart diseases and their management in Cameroon.

    Science.gov (United States)

    Tantchou Tchoumi, J C; Ambassa, J C; Chelo, D; Djimegne, F Kamdem; Giamberti, A; Cirri, S; Kingue, S; Butera, G

    2011-02-01

    The aim of the study was to investigate the occurrence, pattern and clinical aspects of congenital heart diseases and their management in Cameroon. In this multicentred retrospective study from January 2006 till November 2009, out of 51,636 consulting in three referral centres, 505 were recruited. All the patients presented with the following symptoms: cyanosis, clubbing, frequent respiratory tract infections, failure to thrive, growth retardation, precordial murmur and dyspnoea. Patients were sent for the screening of congenital heart disease. After the comprehensive Doppler echocardiography, the recruited patients were diagnosed with congenital (67.2%) and in few, acquired heart disease. Heart murmur, dyspnoea and growth retardation was the triad mostly encountered. The occurrence of congenital heart diseases in Cameroon is 9.87%. In Douala, isolated ventricular septal defect, interatrial septal defect and isolated pulmonary valve stenosis were more diagnosed than in Shisong (P abroad; 9% in the cardiac centre. Our data show that congenital heart diseases are represented in Cameroon as in the literature; isolated ventricular septal defect is the predominant pathology.

  7. 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

  8. Drivers of Live Cattle Price in the Livestock Trading System of Central Cameroon.

    Science.gov (United States)

    Motta, Paolo; Handel, Ian G; Rydevik, Gustaf; Hamman, Saidou M; Ngwa, Victor Ngu; Tanya, Vincent N; Morgan, Kenton L; Bronsvoort, Barend M deC; Porphyre, Thibaud

    2017-01-01

    Livestock production and trade are critical for the food security and welfare of rural households in sub-Saharan Africa. In Cameroon, animal trade consists mainly of live cattle commercialized through livestock markets. Identifying the factors contributing to cattle price formation is critical for designing effective policies for sustainable production and for increasing food availability. In this study, we evaluated the influence of a range of individual- and market-level factors on the price of cattle that were sold in all transactions (n = 118,017) recorded over a 12-month period from 31 livestock markets in the main cattle production area of the country. An information-theoretic approach using a generalized additive mixed-effect model was implemented to select the best explanatory model as well as evaluate the robustness of the identified drivers and the predictive ability of the model. The age and gender of the cattle traded were consistently found to be important drivers of the price (p traded live cattle (p traded, nearly 50% of the observed variation in live cattle prices was explained by the final model. Ultimately, our model gives a large scale overview of drivers of cattle price formation in Cameroon and to our knowledge is the first study of this scale in Central Africa. Our findings represent an important milestone in designing efficient and sustainable animal health management programme in Cameroon and ensure livelihood sustainability for rural households.

  9. 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

    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.

  10. Assessment of trace metal pollution in sediments and intertidal fauna at the coast of Cameroon.

    Science.gov (United States)

    Ngeve, Magdalene N; Leermakers, Martine; Elskens, Marc; Kochzius, Marc

    2015-06-01

    Coastal systems act as a boundary between land and sea. Therefore, assessing pollutant concentrations at the coast will provide information on the impact that land-based anthropogenic activities have on marine ecosystems. Sediment and fauna samples from 13 stations along the whole coast of Cameroon were analyzed to assess the level of trace metal pollution in sediments and intertidal fauna. Sediments showed enrichment of As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, V, and Zn. However, pollution of greater concern was observed for Cd, Cr, Cu, Ni, and Zn at the northern stations. Some sites recorded trace metal levels higher than recommended in sediment quality guidelines. Species diversity was low, and high bioaccumulation of trace metals was observed in biological samples. Some edible gastropod species accumulated trace metals above the safety limits of the World Health Organization, European Medicine Agency, and the US Environment Protection Agency. Although industrial pollution is significant along Cameroon's coast, natural pollution from the volcano Mount Cameroon is also of concern.

  11. Rethinking and Reconfiguring English Language Education: Averting Linguistic Genocide in Cameroon

    Directory of Open Access Journals (Sweden)

    Carlous Muluh Nkwetisama

    2017-09-01

    Full Text Available The over 285 indigenous languages of Cameroon may be crushed by the English language. To ensure a sustainable linguistic ecological balance whose peace is undoubtedly threatened by the global imperialistic terrors of English colonialism, an overhaul of ELT practitioners is needed. The English language is taught and learned in Cameroon against a conflictual linguistic platform of French (the other official language of questionable equal status as English, Pidgin English and over 285 indigenous languages. Of these local languages, just about 40 are currently being used (taught in education at the different levels of education in the country. The aim of this paper was to examine the English language politics, practices and teaching. It thereafter evaluated English language teachers’ perception of the so called English Language Teaching Tenets. It also aimed at assessing the functional load of English and it ascertained the extent to which it was threatening the development of local languages as well as effective access to education in Cameroon.

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

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    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.

  13. 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.

  14. Neuropsychology in Cameroon: first normative data for cognitive tests among school-aged children.

    Science.gov (United States)

    Ruffieux, N; Njamnshi, A K; Mayer, E; Sztajzel, R; Eta, S C; Doh, R F; Kengne, A-M; Ngamaleu, R N; Chanal, J; Verdon, V; Hauert, C-A

    2010-01-01

    Very few normative data on psychometric tests are available in sub-Saharan African countries, in spite of the obvious needs and potential benefits from psychological and neuropsychological examination in these contexts. The goal of the ongoing overall project is to assess the cognitive functioning of Cameroonian school-aged children suffering from Sickle Cell Disease. For this purpose, normative data on psychometric tests adapted to the Cameroonian cultural context had to first be established. 125 "healthy" school-aged Cameroonian children were recruited from public schools in the city of Yaounde and were given a battery of 14 cognitive tests assessing executive functions and memory. Criteria for tests inclusions were: simplicity of administration, few verbal demand, and broad cross-cultural applicability. Results allow concluding that the battery is appropriate for neuropsychological evaluation in Cameroon, with the exception of the Block Design test (WISC-IV) and a Verbal Phonemic Fluency test. A factor analysis shows a division of the tests in a four-factors model that is very consistent with the expected measures of the tests. Effects of gender, age, and education are also discussed. this study is the first to report normative data on neuropsychological tests among children in Cameroon and constitutes an initial step for the advancement of neuropsychology in this country in particular and in sub-Saharan Africa in general. The battery is currently used in Cameroon with children suffering from Sickle Cell Disease as an aid to detect cerebrovascular complications.

  15. Parentage analysis and outcrossing patterns in cacao (Theobroma cacao L.) farms in Cameroon.

    Science.gov (United States)

    Efombagn, M I B; Sounigo, O; Eskes, A B; Motamayor, J C; Manzanares-Dauleux, M J; Schnell, R; Nyassé, S

    2009-07-01

    The present study investigates the parentage of farm accessions in Cameroon using data from 12 microsatellite loci. Bayesian analysis suggests that 25.5% of the 400 farm accessions studied is still closely related to the traditional Amelonado variety called 'German Cocoa' by the farmers. Another 46.3% of the farm accessions were found to be direct descendants (20.8% first-generation (F1) hybrids and 25.5% selfed genotypes) from 24 parental clones used in biclonal seed gardens (BSGs) established in the 1970s in southern and western Cameroon. Furthermore, 28.3% of farm accessions appeared to descent from uncontrolled pollination events in cacao farms, which could be related to a common practice of cacao growers to use seeds collected in their own farm for new plantings. All farm accessions descending from BSG could be individually related through parentage analysis to the 24 progenitors of the BSG. Only 25% of progenies distributed from BSG corresponded to F1 hybrids combinations originally planned to be released. Significant biparental inbreeding estimates were observed for all 'traditional' farms and for most 'F1 hybrids' farms due to presence of a high proportion of selfed accessions. Biparental inbreeding occurs when plants receive pollen from genetically related neighbors. High levels of outcrossing observed in 'mixed' farms might be explained by the admixture of traditional varieties and BSG progenies. The implications of our finding for management of seed gardens and for further breeding using farm accessions in Cameroon are discussed.

  16. 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

  17. 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.

  18. Seroprevalence of hepatitis B virus infection in Cameroon: a systematic review and meta-analysis.

    Science.gov (United States)

    Bigna, Jean Joel; Amougou, Marie A; Asangbeh, Serra Lem; Kenne, Angeladine Malaha; Noumegni, Steve Raoul N; Ngo-Malabo, Elodie T; Noubiap, Jean Jacques

    2017-06-30

    Better knowledge of hepatitis B virus (HBV) infection prevalence at the national level can help to implement pertinent strategies to address HBV related burden. The aim was to estimate the seroprevalence of HBV infection in Cameroon. Systematic review and meta-analysis. People residing in Cameroon. Electronic databases including PubMed/MEDLINE, African Journals Online (AJOL), ScienceDirect, WHO-Afro Library, WHO-IRIS, African Index Medicus, National Institute of Statistics and National AIDS Control Committee, Cameroon; regardless of language and from 1 January 2000 to 30 September 2016. This was completed with a manual search of references of relevant papers. Risk of bias in methodology of studies was measured using the Newcastle-Ottawa Scale. Out of 511 retrieved papers, 44 studies with a total of 105 603 individuals were finally included. The overall pooled seroprevalence was 11.2% (95% CI 9.7% to 12.8%) with high heterogeneity between studies ( I 2 =97.9%). Egger's test showed no publication bias (p=0.167). A sensitivity analysis excluding individuals at high risk of HBV infection and after adjustment using trim and fill method showed a pooled seroprevalence of 10.6% (95% CI 8.6% to 12.6%) among 100 501 individuals (general population, blood donors and pregnant women). Sources of heterogeneity included geographical regions across country and setting (rural 13.3% vs urban 9.0%), and implementation of HBV universal immunisation (born after 9.2% vs born before 0.7%). Sex, site, timing of data collection, HBV screening tools and methodological quality of studies were not sources of heterogeneity. Only a third of the studies had low risk of bias in their methodology. The seroprevalence of HBV infection in Cameroon is high. Effective strategies to interrupt the transmission of HBV are urgently required. Specific attention is needed for rural settings, certain regions and people born before the implementation of the HBV universal immunisation programme in Cameroon

  19. Active Volcanic Eruptions on Io

    Science.gov (United States)

    1996-01-01

    Six views of the volcanic plume named Prometheus, as seen against Io's disk and near the bright limb (edge) of the satellite by the SSI camera on the Galileo spacecraft during its second (G2) orbit of Jupiter. North is to the top of each frame. To the south-southeast of Prometheus is another bright spot that appears to be an active plume erupting from a feature named Culann Patera. Prometheus was active 17 years ago during both Voyager flybys, but no activity was detected by Voyager at Culann. Both of these plumes were seen to glow in the dark in an eclipse image acquired by the imaging camera during Galileo's first (G1) orbit, and hot spots at these locations were detected by Galileo's Near-Infrared Mapping Spectrometer.The plumes are thought to be driven by heating sulfur dioxide in Io's subsurface into an expanding fluid or 'geyser'. The long-lived nature of these eruptions requires that a substantial supply of sulfur dioxide must be available in Io's subsurface, similar to groundwater. Sulfur dioxide gas condenses into small particles of 'snow' in the expanding plume, and the small particles scatter light and appear bright at short wavelengths. The images shown here were acquired through the shortest-wavelength filter (violet) of the Galileo camera. Prometheus is about 300 km wide and 75 km high and Culann is about 150 km wide and less than 50 km high. The images were acquired on September 4, 1996 at a range of 2,000,000 km (20 km/pixel resolution). Prometheus is named after the Greek fire god and Culann is named after the Celtic smith god.The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can

  20. 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

  1. A new way to detect volcanic plumes

    Science.gov (United States)

    Larson, Kristine M.

    2013-06-01

    of volcanic plumes, especially ash-laden ones, is important both for public health and aircraft safety. A variety of geophysical tools and satellite data are used to monitor volcanic eruptions and to predict the movement of ash. However, satellite-based methods are restricted by time of day and weather, while radars are often unavailable because of cost/portability. Here a method is proposed to detect volcanic plumes using GPS signal strength data. The strengths and limitations of the method are assessed using GPS data collected during the 2008 and 2009 eruptions of the Okmok and Mt. Redoubt volcanoes. Plume detections using this GPS technique are consistent with independently collected seismic and radar data.

  2. Ozone depletion following future volcanic eruptions

    Science.gov (United States)

    Eric Klobas, J.; Wilmouth, David M.; Weisenstein, Debra K.; Anderson, James G.; Salawitch, Ross J.

    2017-07-01

    While explosive volcanic eruptions cause ozone loss in the current atmosphere due to an enhancement in the availability of reactive chlorine following the stratospheric injection of sulfur, future eruptions are expected to increase total column ozone as halogen loading approaches preindustrial levels. The timing of this shift in the impact of major volcanic eruptions on the thickness of the ozone layer is poorly known. Modeling four possible climate futures, we show that scenarios with the smallest increase in greenhouse gas concentrations lead to the greatest risk to ozone from heterogeneous chemical processing following future eruptions. We also show that the presence in the stratosphere of bromine from natural, very short-lived biogenic compounds is critically important for determining whether future eruptions will lead to ozone depletion. If volcanic eruptions inject hydrogen halides into the stratosphere, an effect not considered in current ozone assessments, potentially profound reductions in column ozone would result.

  3. Tropical Volcanic Soils From Flores Island, Indonesia

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    Hikmatullah

    2010-01-01

    Full Text Available Soils that are developed intropical region with volcanic parent materials have many unique properties, and high potential for agricultural use.The purpose of this study is to characterize the soils developed on volcanic materials from Flores Island, Indonesia,and to examine if the soils meet the requirements for andic soil properties. Selected five soils profiles developed fromandesitic volcanic materials from Flores Island were studied to determine their properties. They were compared intheir physical, chemical and mineralogical characteristics according to their parent material, and climatic characteristicdifferent. The soils were developed under humid tropical climate with ustic to udic soil moisture regimes withdifferent annual rainfall. The soils developed from volcanic ash parent materials in Flores Island showed differentproperties compared to the soils derived from volcanic tuff, even though they were developed from the sameintermediary volcanic materials. The silica contents, clay mineralogy and sand fractions, were shown as the differences.The different in climatic conditions developed similar properties such as deep solum, dark color, medium texture, andvery friable soil consistency. The soils have high organic materials, slightly acid to acid, low to medium cationexchange capacity (CEC. The soils in western region have higher clay content and showing more developed than ofthe eastern region. All the profiles meet the requirements for andic soil properties, and classified as Andisols order.The composition of sand mineral was dominated by hornblende, augite, and hypersthenes with high weatherablemineral reserves, while the clay fraction was dominated by disordered kaolinite, and hydrated halloysite. The soilswere classified into subgroup as Thaptic Hapludands, Typic Hapludands, and Dystric Haplustands

  4. Volcanic air pollution hazards in Hawaii

    Science.gov (United States)

    Elias, Tamar; Sutton, A. Jeff

    2017-04-20

    Noxious sulfur dioxide gas and other air pollutants emitted from Kīlauea Volcano on the Island of Hawai‘i react with oxygen, atmospheric moisture, and sunlight to produce volcanic smog (vog) and acid rain. Vog can negatively affect human health and agriculture, and acid rain can contaminate household water supplies by leaching metals from building and plumbing materials in rooftop rainwater-catchment systems. U.S. Geological Survey scientists, along with health professionals and local government officials are working together to better understand volcanic air pollution and to enhance public awareness of this hazard.

  5. 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

  6. Volcanic Pipe of the Namuaiv Mountain

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    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

  7. Assessing Volcanic Risk in Saudi Arabia

    Science.gov (United States)

    Lindsay, Jan Marie; Rashad Moufti, Mohammed

    2014-08-01

    The Kingdom of Saudi Arabia has numerous large monogenetic volcanic fields, known locally as "harrats." The largest of these, Harrat Rahat (Figure 1), produced a basaltic fissure eruption in 1256 C.E. with lava flows traveling within 20 kilometers of the city Al-Madinah, which currently has a population of 1.5 million plus an additional 3 million pilgrims annually. With more than 950 visible vents and periodic seismic swarms, an understanding of the risk of future eruptions in this volcanic field is vital.

  8. 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.

  9. AVAL - The ASTER Volcanic Ash Library

    Science.gov (United States)

    Williams, D.; Ramsey, M. S.

    2016-12-01

    Volcanic ash is a rich data source for understanding the causal mechanisms behind volcanic eruptions. Petrologic and morphometric information can provide direct information on the characteristics of the parent magma. Understanding how erupted ash interacts with the atmosphere can help quantify the effect that explosive volcanism has on the local to regional climate, whereas a measure of the particle size distribution enables more accurate modeling of plume propagation. Remote sensing is regularly employed to monitor volcanic plumes using a suite of high temporal/low spatial resolution sensors. These methods employ radiative transfer modeling with assumptions of the transmissive properties of infrared energy through the plume to determine ash density, particle size and sulfur dioxide content. However, such approaches are limited to the optically-transparent regions, and the low spatial resolution data are only useful for large-scale trends. In a new approach, we are treating the infrared-opaque regions of the plume in a similar way to a solid emitting surface. This allows high spatial resolution orbital thermal infrared data from the dense proximal plume to be modeled using a linear deconvolution approach coupled with a spectral library to extract the particle size and petrology. The newly created ASTER Volcanic Ash Library (AVAL) provides the end member spectral suite, and is comprised of laboratory emission measurements of volcanic ash taken from a variety of different volcanic settings, to obtain a wide range of petrologies. These samples have been further subdivided into particle size fractions to account for spectral changes due to diffraction effects. Once mapped to the ASTER sensor's spectral resolution, this library is applied to image data and the plume deconvolved to estimate composition and particle size. We have analyzed eruptions at the Soufrière Hills Volcano, Montserrat, Chaitén and Puyehue-Cordón Caulle, both Chile, and Eyjafjallajökull, Iceland

  10. Consequences of powerful volcanic eruptions according to dendrochronological data

    Science.gov (United States)

    Kasatkina, E. A.; Shumilov, O. I.; Timonen, M.; Kanatjev, A. G.

    2013-07-01

    For the first time we identify the peculiarities of the effect of the most powerful (VEI > 5) volcanic eruptions on the regional climate of the Murmansk region on the basis of Kola Peninsula dendrochronological data for a period of more than 560 years. The analysis was based on the tree-ring chronology covering the period from 1445 to 2005. This chronology was derived from Pinus sylvestris samples collected near the northern tree line at Loparskaya station (68°37' N; 33°14' E). The data were processed using modern techniques adopted in dendrochronology (cross dating and standardization). We reveal a significant decrease in the radial tree-ring growth over 8 years (on average) after the eruptions; then its value is restored to the normal level. This finding will help evaluate the response of the regional climate system to external climate forcings in this economically important region for Russia.

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

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    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.

  12. Widespread Neogene and Quaternary Volcanism on Central Kerguelen Plateau, Southern Indian Ocean

    Science.gov (United States)

    Duncan, R. A.; Falloon, T.; Quilty, P. G.; Coffin, M. F.

    2016-12-01

    We report new age determinations and compositions for rocks from 18 dredge hauls collected from eight submarine areas across Central Kerguelen Plateau (CKP). Sea knolls and volcanic fields with multiple small cones were targeted over a 125,000 km2 region that includes Heard and McDonald islands. Large early Miocene (16-22 Ma) sea knolls rise from the western margin of the CKP and are part of a NNW-SSE line of volcanic centers that lie between Îles Kerguelen and Heard and McDonald islands. A second group of large sea knolls is aligned E-W across the center of this region. We see evidence of much younger activity (5 Ma to present) in volcanic fields to the north of, and up to 300 km NE of Heard Island. Compositions include basanite, basalt, and trachybasalt, that are broadly similar to plateau lava flows from nearby Ocean Drilling Program (ODP) Site 1138, lower Miocene lavas at Îles Kerguelen, dredged rocks from the early Miocene sea knolls, and Big Ben lavas from Heard Island. Geochemical data indicate decreasing fractions of mantle source melting with time. The western line of sea knolls has been related to hotspot activity now underlying the Heard Island area. In view of the now recognized much larger area of young volcanic activity, we propose that a broad region of CKP became volcanically active in Neogene time due to incubation of plume material at the base of the relatively stationary overlying plateau. The presence of pre-existing crustal faults promotes access for melts from the Heard mantle plume to rise to the surface.

  13. 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 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 thanks grant DGAPA-UNAM-PAPIIT IN-104615.

  14. VOLCANIC EMISSIONS AND DISTAL PALAEOENVIRONMENTAL IMPACTS IN NEW ZEALAND

    OpenAIRE

    GILES, TERESA MARY

    1999-01-01

    This thesis is a palaeoenviromnental investigation into possible non-climatic effects on the environment from volcanic ash fall and toxic emissions outside the blast zone of a volcanic eruption. These effects are determined from palynological and geochemical changes following tephra fall at a range of sites across the North Island of New Zealand which were located at increasing distances from the main volcanic source, the Taupo Volcanic Zone. These sites collectively covered a wid...

  15. Serving in Africa: US Peace Corps in Cameroon Dienst in Afrika: Das US Peace Corps in Kamerun

    Directory of Open Access Journals (Sweden)

    Julius A. Amin

    2013-01-01

    Full Text Available Based on a variety of primary sources including recently declassified documents, interviews in Cameroon, letters, and Peace Corps Volunteers’ personal correspondence, this study examines the service of the US Peace Corps in “Agroforestry” and “Small Enterprise Development” in Cameroon. The study argues that Volunteers were ill trained, ill prepared, and ill equipped for service in Cameroon, and as a result did not achieve Goal 1 of the Peace Corps Act, which calls on the agency to assist developing nations in gaining “trained manpower”. The study has broader implications, as it raises questions about the relevance of Peace Corps-like organizations in Cameroon, and in African nations as a whole. It focuses on Cameroon for a variety of reasons, among which is that Cameroon is one of only three nations in Africa in which Volunteers have served uninterruptedly since 1962.Dieser Beitrag untersucht die Entwicklungshilfepraxis des US Peace Corps in Kamerun in den Bereichen Agroforstwirtschaft und Kleinunternehmen. Er basiert auf Primärquellen, wie erst kürzlich freigegebenen Dokumenten, privaten Korrespondenzen der Entwicklungshelfer („Volunteers“ und Interviews in Kamerun. Der Autor kommt zu dem Schluss, dass die fachliche Qualifikation der Peace-Corps-Entwicklungshelfer nicht angemessen war und dass sie auf ihre Aufgaben in Kamerun schlecht vorbereitet und nur unzureichend ausgerüstet wurden. Aus diesem Grund sei das vorrangige Ziel des Peace Corps – Entwicklungsländer bei der Ausbildung von Arbeitskräften zu unterstützen – gar nicht zu erreichen gewesen. Er stellt darüber hinaus die Frage nach der Relevanz entsprechender Organisationen in Kamerun und in Afrika generell. Der Beitrag konzentriert sich unter anderem deshalb auf Kamerun, weil dies eines der drei Länder Afrikas ist, in denen seit 1962 ununterbrochen Entwicklungshelfer des Peace Corps gearbeitet haben.

  16. Molecular characterization and phylogenetic relatedness of dog-derived Rabies Viruses circulating in Cameroon between 2010 and 2016.

    Directory of Open Access Journals (Sweden)

    Serge Alain Sadeuh-Mba

    2017-10-01

    Full Text Available Rabies is enzootic among dog populations in some parts of Cameroon and the risk of human rabies is thought to be steadily high in these regions. However, the molecular epidemiology of circulating Rabies Virus (RABV has been hardly considered in Cameroon as well as in most neighboring central African countries. To address this fundamental gap, 76 nucleoprotein (N gene sequences of dog-derived RABV were obtained from 100 brain specimens sampled in Cameroon from 2010 to 2016. Studied sequences were subjected to molecular and phylogenetic analyses with reference strains retrieved from databases. The 71 studied Africa-1 isolates displayed 93.5-100% nucleotide (nt and 98.3-100% amino-acid (aa identities to each other while, the 5 studied Africa-2 isolates shared 99.4-99.7% sequence similarities at nt and aa levels. Maximum Likelihood based phylogenies inferred from nucleotide sequences confirmed all studied RABV isolates as members of the dog-related species 1 of the Lyssavirus genus. Individual isolates could be unambiguously assigned as either the Africa-1 subclade of the Cosmopolitan clade or the Africa 2 clade. The Africa-1 subclade appeared to be more prevalent and diversified. Indeed, 70 studied isolates segregated into 3 distinct circulating variants within Africa-1a lineage while a unique isolate was strikingly related to the Africa-1b lineage known to be prevalent in the neighboring Central African Republic and eastern Africa. Interestingly, all five Africa-2 isolates fell into the group-E lineage even though they appeared to be loosely related to databases available reference RABV; including those previously documented in Cameroon. This study uncovered the co-circulation of several Africa-1 and Africa-2 lineages in the southern regions of Cameroon. Striking phylogenetic outcasts to the geographic differentiation of RABV variants indicated that importation from close regions or neighboring countries apparently contributes to the sustainment

  17. Molecular characterization and phylogenetic relatedness of dog-derived Rabies Viruses circulating in Cameroon between 2010 and 2016.

    Science.gov (United States)

    Sadeuh-Mba, Serge Alain; Momo, Jean Blaise; Besong, Laura; Loul, Sévérin; Njouom, Richard

    2017-10-01

    Rabies is enzootic among dog populations in some parts of Cameroon and the risk of human rabies is thought to be steadily high in these regions. However, the molecular epidemiology of circulating Rabies Virus (RABV) has been hardly considered in Cameroon as well as in most neighboring central African countries. To address this fundamental gap, 76 nucleoprotein (N) gene sequences of dog-derived RABV were obtained from 100 brain specimens sampled in Cameroon from 2010 to 2016. Studied sequences were subjected to molecular and phylogenetic analyses with reference strains retrieved from databases. The 71 studied Africa-1 isolates displayed 93.5-100% nucleotide (nt) and 98.3-100% amino-acid (aa) identities to each other while, the 5 studied Africa-2 isolates shared 99.4-99.7% sequence similarities at nt and aa levels. Maximum Likelihood based phylogenies inferred from nucleotide sequences confirmed all studied RABV isolates as members of the dog-related species 1 of the Lyssavirus genus. Individual isolates could be unambiguously assigned as either the Africa-1 subclade of the Cosmopolitan clade or the Africa 2 clade. The Africa-1 subclade appeared to be more prevalent and diversified. Indeed, 70 studied isolates segregated into 3 distinct circulating variants within Africa-1a lineage while a unique isolate was strikingly related to the Africa-1b lineage known to be prevalent in the neighboring Central African Republic and eastern Africa. Interestingly, all five Africa-2 isolates fell into the group-E lineage even though they appeared to be loosely related to databases available reference RABV; including those previously documented in Cameroon. This study uncovered the co-circulation of several Africa-1 and Africa-2 lineages in the southern regions of Cameroon. Striking phylogenetic outcasts to the geographic differentiation of RABV variants indicated that importation from close regions or neighboring countries apparently contributes to the sustainment of the enzootic

  18. Compositional Differences between Felsic Volcanic rocks from the ...

    African Journals Online (AJOL)

    Pliocene felsic rift margin and Quaternary rift center volcanic rocks from the northern Main Ethiopian Rift (MER) exhibit contrasts in major and trace element contents and Sr-Nd isotopic ratios. Quaternary rift center felsic volcanic rocks are mainly peralkaline trachytes and rhyolites, whereas Pliocene felsic rift margin volcanic ...

  19. Improving volcanic ash forecasts with ensemble-based data assimilation

    NARCIS (Netherlands)

    Fu, Guangliang

    2017-01-01

    The 2010 Eyjafjallajökull volcano eruption had serious consequences to civil aviation. This has initiated a lot of research on volcanic ash forecasting in recent years. For forecasting the volcanic ash transport after eruption onset, a volcanic ash transport and diffusion model (VATDM) needs to be

  20. Deccan volcanism, the KT mass extinction and dinosaurs

    Indian Academy of Sciences (India)

    2009-10-29

    Oct 29, 2009 ... Recent advances in Deccan volcanic studies indicate three volcanic phases with the phase-1 at 67.5 Ma followed by a 2 m.y. period of quiescence. Phase-2 marks the main Deccan volcanic eruptions in Chron 29r near the end of the Maastrichtian and accounts for ∼80% of the entire 3500 m thick Deccan ...

  1. 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...

  2. The Elusive Evidence of Volcanic Lightning.

    Science.gov (United States)

    Genareau, K; Gharghabi, P; Gafford, J; Mazzola, M

    2017-11-14

    Lightning strikes are known to morphologically alter and chemically reduce geologic formations and deposits, forming fulgurites. A similar process occurs as the result of volcanic lightning discharge, when airborne volcanic ash is transformed into lightning-induced volcanic spherules (LIVS). Here, we adapt the calculations used in previous studies of lightning-induced damage to infrastructure materials to determine the effects on pseudo-ash samples of simplified composition. Using laboratory high-current impulse experiments, this research shows that within the lightning discharge channel there is an ideal melting zone that represents roughly 10% or less of the total channel radius at which temperatures are sufficient to melt the ash, regardless of peak current. The melted ash is simultaneously expelled from the channel by the heated, expanding air, permitting particles to cool during atmospheric transport before coming to rest in ash fall deposits. The limited size of this ideal melting zone explains the low number of LIVS typically observed in volcanic ash despite the frequent occurrence of lightning during explosive eruptions.

  3. Amazonian volcanism inside Valles Marineris on Mars

    Czech Academy of Sciences Publication Activity Database

    Brož, Petr; Hauber, E.; Wray, J. J.; Michael, G.

    2017-01-01

    Roč. 473, September (2017), s. 122-130 ISSN 0012-821X Institutional support: RVO:67985530 Keywords : Mars * Valles Marineris * volcanism * scoria cone * hydrothermal activity Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 4.409, year: 2016

  4. Geochemistry and petrogenesis of anorogenic basic volcanic ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    anorogenic setting for the basic rocks of Kundal area is suggested, which is in conformity with the similar setting for Malani Igneous Suite. 1. Introduction. The Malani magmatism is characterized by sub- volcanic setting, volcano-plutonic ring structures, anorogenic (A-type), high heat producing magma- tism and controlled by ...

  5. Assessing quality in volcanic ash soils

    Science.gov (United States)

    Terry L. Craigg; Steven W. Howes

    2007-01-01

    Forest managers must understand how changes in soil quality resulting from project implementation affect long-term productivity and watershed health. Volcanic ash soils have unique properties that affect their quality and function; and which may warrant soil quality standards and assessment techniques that are different from other soils. We discuss the concept of soil...

  6. Halogen Chemistry in Volcanic Plumes (Invited)

    Science.gov (United States)

    Roberts, Tjarda

    2017-04-01

    Volcanoes release vast amounts of gases and particles in the atmosphere. Volcanic halogens (HF, HCl, HBr, HI) are co-emitted alongside SO2, and observations show rapid formation of BrO and OClO in the plume as it disperses into the troposphere. The development of 1D and Box models (e.g. PlumeChem) that simulate volcanic plume halogen chemistry aims to characterise how volcanic reactive halogens form and quantify their atmospheric impacts. Following recent advances, these models can broadly reproduce the observed downwind BrO/SO2 ratios using "bromine-explosion" chemistry schemes, provided they use a "high-temperature initialisation" to inject radicals (OH, Cl, Br and possibly NOx) which "kick-start" the low-temperature chemistry cycles that convert HBr into reactive bromine (initially as Br2). The modelled rise in BrO/SO2 and subsequent plateau/decline as the plume disperses downwind reflects cycling between reactive bromine, particularly Br-BrO, and BrO-HOBr-BrONO2. BrCl is produced when aerosol becomes HBr-depleted. Recent model simulations suggest this mechanism for reactive chlorine formation can broadly account for OClO/SO2 reported at Mt Etna. Predicted impacts of volcanic reactive halogen chemistry include the formation of HNO3 from NOx and depletion of ozone. This concurs with HNO3 widely reported in volcanic plumes (although the source of NOx remains under question), as well as observations of ozone depletion reported in plumes from several volcanoes (Mt Redoubt, Mt Etna, Eyjafjallajokull). The plume chemistry can transform mercury into more easily deposited and potentially toxic forms, for which observations are limited. Recent incorporation of volcanic halogen chemistry in a 3D regional model of degassing from Ambrym (Vanuatu) also predicts how halogen chemistry causes depletion of OH to lengthen the SO2 lifetime, and highlights the potential for halogen transport from the troposphere to the stratosphere. However, the model parameter-space is vast and

  7. Stability of volcanic conduits during explosive eruptions

    Science.gov (United States)

    Aravena, Álvaro; de'Michieli Vitturi, Mattia; Cioni, Raffaello; Neri, Augusto

    2017-06-01

    Geological evidences of volcanic conduit widening are common in most pyroclastic deposits (e.g. presence of lithic fragments from different depths), suggesting a continuous modification of the conduit geometry during volcanic eruptions. However, the controlling factors of the mechanisms driving conduit enlargement (e.g. erosion, local collapse) are still partially unclear, as well as the influence of conduit geometry on the eruptive dynamics. Although numerical models have been systematically employed to study volcanic conduits, their mechanical stability and the eruptive dynamics related to non-cylindrical conduits have been poorly addressed. We present here a 1D steady-state model which includes the main processes experimented by ascending magmas (i.e. crystallization, rheological changes, fragmentation, drag forces, outgassing and degassing), and the application of two mechanical stability criteria (Mohr-Coulomb and Mogi-Coulomb), in order to study the collapse conditions of volcanic conduits during a representative explosive rhyolitic eruption. It emerges that mechanical stability of volcanic conduits is mainly controlled by its radial dimension, and a minimum radius for reaching stable conditions can be computed, as a function of water content and inlet overpressure. Additionally, for a set of input parameters thought typical of explosive rhyolitic volcanism, we estimated a minimum magma flux for developing a mechanically stable conduit ( 7 • 107 - 3 • 108 kg/s). Results are consistent with the unsteady character usually observed in sub-Plinian eruptions, opposite to mainly stationary Plinian eruptions, commonly characterized by higher magma discharge rates. We suggest that cylindrical conduits represent a mechanically stable configuration only for large radii. Because the instability conditions are not uniform along the conduit, the widening processes probably lead to conduit geometries with depth-varying width. Consequently, as our model is able to

  8. 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...

  9. 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

  10. Volcanic field elongation, vent distribution and tectonic evolution of continental rift: The Main Ethiopian Rift example

    Science.gov (United States)

    Mazzarini, Francesco; Le Corvec, Nicolas; Isola, Ilaria; Favalli, Massimiliano

    2015-04-01

    Magmatism and faulting operate in continental rifts and interact at a variety of scales, however their relationship is complex. The African rift, being the best example for both active continental rifting and magmatism, provides the ideal location to study the interplay between the two mechanisms. The Main Ethiopian Rift (MER), which connects the Afar depression in the north with the Turkana depression and Kenya Rift to the south, consists of two distinct systems of normal faults and its floor is scattered with volcanic fields formed by tens to several hundreds monogenetic, generally basaltic, small volcanoes and composite volcanoes and small calderas. The distribution of vents defines the overall shape of the volcanic field. Previous work has shown that the distribution of volcanic vents and the shape of a field are linked to its tectonic environment and its magmatic system. In order to distinguish the impact of each mechanism, we analyzed four volcanic fields located at the boundary between the central and northern MER, three of them (Debre Zeyit, Wonji and Kone) grew in the rift valley and one (Akaki) on the western rift shoulder. The elongation and shape of the fields were analyzed based on their vent distribution using the Principal Component Analysis (PCA), the Vent-to-Vent Distance (VVD), and the two dimensional symmetric Gaussian kernel density estimate methods. We extracted from these methods several parameters characterizing the spatial distribution of points (e.g., eccentricity (e), eigenvector index (evi), angular dispersion (Da)). These parameters allow to define at least three types of shape for volcanic fields: strong elongate (line and ellipse), bimodal/medium elongate (ellipse) and dispersed (circle) shapes. Applied to the natural example, these methods well differentiate each volcanic field. For example, the elongation of the field increases from shoulder to rift axis inversely to the angular dispersion. In addition, the results show that none of

  11. Remote Sensing of Volcanic Clouds: Sulfur Gases and Plume Top Topography

    Science.gov (United States)

    Crisp, Joy A.

    1999-01-01

    New absorption line parameters for H2S were published and submitted to the Gestion et Etude des Informations Spectroscopiques Atmospheriques (GEISA) and high resolution transmission molecular absorption (HITRAN) databases. These new absorption line parameters will make it possible to use observations from the future Tropospheric Emission Spectrometer (TES) instrument [Earth Observing System (EOS) Chemistry Mission (CHEM) platform] to make more accurate H2S measurements if it observes an H2S-rich volcanic cloud. H2S is the second most abundant volcanic sulfur gas, and like SO2, it also converts to H2SO4 aerosols and can have a climate impact. A paper on the Moderate-resolution Imaging-Spectroradiometer (MODIS) SO2 alert is being revised. New aspects in the revision include verification of the SO2 alert during the EOS mission; factors affecting SO2 detection at thermal infrared, ultraviolet, and microwave wavelengths; radiative transfer tests; more description of satellite instruments; and thermal surface alert installed for MODIS. Her research involves the use of remote sensing to generate maps of plume top altitude. This parameter is important for models of volcanic eruption, aircraft hazards, and climate impact. The topographic shape of the top surface of a volcanic plume can provide information necessary to understand the physics controlling the injection and dispersal of a volcanic plume in the atmosphere. Glaze et al. describe the application of a photoclinometric technique to volcanic plumes. The software algorithm has been improved to account for more general plume and illumination geometries and for easily extracting position information directly from Advanced Very High-Resolution Radiometer (AVHRR) level 1B data. Testing of the algorithm has focused on acquiring AVHRR data for a variety of volcanic plumes in an effort to identify problems with the software as well as model sensitivities. The plumes chosen were erupted from volcanoes at a variety of

  12. 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.

  13. Cooling Rates of Lunar Volcanic Glass Beads

    Science.gov (United States)

    Hui, Hejiu; Hess, Kai-Uwe; Zhang, Youxue; Peslier, Anne; Lange, Rebecca; Dingwell, Donald; Neal, Clive

    2016-01-01

    It is widely accepted that the Apollo 15 green and Apollo 17 orange glass beads are of volcanic origin. The diffusion profiles of volatiles in these glass beads are believed to be due to degassing during eruption (Saal et al., 2008). The degree of degassing depends on the initial temperature and cooling rate. Therefore, the estimations of volatiles in parental magmas of lunar pyroclastic deposits depend on melt cooling rates. Furthermore, lunar glass beads may have cooled in volcanic environments on the moon. Therefore, the cooling rates may be used to assess the atmospheric condition in an early moon, when volcanic activities were common. The cooling rates of glasses can be inferred from direct heat capacity measurements on the glasses themselves (Wilding et al., 1995, 1996a,b). This method does not require knowledge of glass cooling environments and has been applied to calculate the cooling rates of natural silicate glasses formed in different terrestrial environments. We have carried out heat capacity measurements on hand-picked lunar glass beads using a Netzsch DSC 404C Pegasus differential scanning calorimeter at University of Munich. Our preliminary results suggest that the cooling rate of Apollo 17 orange glass beads may be 12 K/min, based on the correlation between temperature of the heat capacity curve peak in the glass transition range and glass cooling rate. The results imply that the parental magmas of lunar pyroclastic deposits may have contained more water initially than the early estimations (Saal et al., 2008), which used higher cooling rates, 60-180 K/min in the modeling. Furthermore, lunar volcanic glass beads could have been cooled in a hot gaseous medium released from volcanic eruptions, not during free flight. Therefore, our results may shed light on atmospheric condition in an early moon.

  14. 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.

  15. Knowledge, Attitude, and Practice on Breast Cancer among Health Professionals in Douala References Hospitals, Cameroon.

    Science.gov (United States)

    Nguefack, Charlotte Tchente; N'djeudjui, Calvin; Engbang, Jean Paul Ndamba; Nana, Théophile Njamen; Ekane, Gregory Halle; Tebeu, Pierre-Marie

    2017-01-13

    In Cameroon, patients with breast cancer are more often diagnosed at stage III and IV, hence the need of preventives actions. Knowledge and attitude of medical personnel may influence their practice with regards to screening and early detection of breast cancer. Very few is known about this subject in Cameroon. The objective was to describe the knowledge, attitude, and practice of health care professionals on breast cancer risk factors, diagnostic methods, and screening. This was a cross-sectional study conducted during a 6-month period, among health professionals of Douala General Hospital and Laquintinie Hospital, Cameroon.Data were collected using a self-administered questionnaire which included demographic characteristics, questions on breast cancer risk factors, screening, and diagnostic methods. Marks were attributed to each question and calculated for each section. Participants fell in four categories of knowledge, attitude, and practice: very weak, weak, good, and excellent. The software XLStat7.5.2 was used for data analysis. Overall, 445 health professionals were interviewed. The average age was 39 ± 9 years. The level of knowledge, attitude, and practice was accessed respectively as weak (50.1%), very good (64.5%), and poor (36.4%). The personal practice of female workers was poor (43.0%). Compared to participants with very weak to weak knowledge, those with good to excellent knowledge had 1.55-fold odds of excellent attitude p knowledge was the participant qualification (academic degree). These results suggest the need for training of health professionals in Douala references hospitals on breast cancer risks factors, diagnostic, and screening methods.

  16. Drivers of Live Cattle Price in the Livestock Trading System of Central Cameroon

    Directory of Open Access Journals (Sweden)

    Paolo Motta

    2018-01-01

    Full Text Available Livestock production and trade are critical for the food security and welfare of rural households in sub-Saharan Africa. In Cameroon, animal trade consists mainly of live cattle commercialized through livestock markets. Identifying the factors contributing to cattle price formation is critical for designing effective policies for sustainable production and for increasing food availability. In this study, we evaluated the influence of a range of individual- and market-level factors on the price of cattle that were sold in all transactions (n = 118,017 recorded over a 12-month period from 31 livestock markets in the main cattle production area of the country. An information-theoretic approach using a generalized additive mixed-effect model was implemented to select the best explanatory model as well as evaluate the robustness of the identified drivers and the predictive ability of the model. The age and gender of the cattle traded were consistently found to be important drivers of the price (p < 0.01. Also, strong, but complex, relationships were found between cattle prices and both local human and bovine population densities. Finally, the model highlighted a positive association between the number of incoming trading connections of a livestock market and the price of the traded live cattle (p < 0.01. Although our analysis did not account for factors informing on specific phenotypic traits nor breed characteristics of cattle traded, nearly 50% of the observed variation in live cattle prices was explained by the final model. Ultimately, our model gives a large scale overview of drivers of cattle price formation in Cameroon and to our knowledge is the first study of this scale in Central Africa. Our findings represent an important milestone in designing efficient and sustainable animal health management programme in Cameroon and ensure livelihood sustainability for rural households.

  17. 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.

  18. Impact of Refugees on Local Health Systems: A Difference-in-Differences Analysis in Cameroon.

    Science.gov (United States)

    Tatah, Lambed; Delbiso, Tefera Darge; Rodriguez-Llanes, Jose Manuel; Gil Cuesta, Julita; Guha-Sapir, Debarati

    2016-01-01

    Hosting refugees may represent a drain on local resources, particularly since external aid is frequently insufficient. Between 2004 and 2011, over 100,000 refugees settled in the eastern border of Cameroon. With little known on how refugee influx affects health services of the hosting community, we investigated the impact of refugees on mother and child health (MCH) services in the host community in Cameroon. We used Cameroon's 2004 and 2011 Demographic and Health Surveys to evaluate changes in MCH indicators in the refugee hosting community. Our outcome variables were antenatal care (ANC) coverage, caesarean delivery rate, place of delivery and child vaccination coverage; whereas the exposure variable was residence in the refugee hosting community. We used a difference-in-differences analysis to compare indicators of the refugee hosting community to a control group selected through propensity score matching from the rest of the country. A total of 10,656 women were included in our 2004 analysis and 7.6% (n = 826) of them resided in the refugee hosting community. For 2011, 15,426 women were included and 5.8% (n = 902) of them resided in the hosting community. Between 2004 and 2011, both the proportion of women delivering outside health facilities and children not completing DPT3 vaccination in the refugee hosting community decreased by 9.0% (95% Confidence Interval (CI): 3.9-14.1%) and 9.6% (95% CI: 7.9-11.3%) respectively. However, ANC attendance and caesarean delivery did not show any significant change. Our findings demonstrate that none of the evaluated MCH service indicators deteriorated (in fact, two of them improved: delivery in health facilities and completing DPT3 vaccine) with the presence of refugees. This suggests evidence disproving the common belief that refugees always have a negative impact on their hosting community.

  19. 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.

  20. Geophysical imaging of metacratonizaton in the northern edge of the Congo craton in Cameroon

    Science.gov (United States)

    Goussi Ngalamo, Jeannot F.; Bisso, D.; Abdelsalam, Mohamed G.; Atekwana, Estella A.; Katumwehe, Andrew B.; Ekodeck, G. E.

    2017-05-01

    We used the World Gravity Map (WGM 2012) data to investigate the Archean Congo craton and the Oubanguides orogenic belt in Cameroon. The Oubanguides orogenic belt constitutes, from northwest to southeast, the Neoproterozoic West Cameroon domain, the Paleoproterozoic-Neoproterozoic Adamawa-Yade domain, and the dominantly Neoproterozoic Yaoundé domain (the crustal expression of the suture zone between the Congo craton and the orogenic terranes). We analyzed the WGM 2012 data to identify different gravity anomalies. We also applied the two-dimensional (2D) radially-averaged power spectral analysis to the WGM 2012 data to estimate the Moho depth. Additionally, we developed a 2D forward gravity model along a Nsbnd S profile to image the lithospheric structure of the Precambrian entities. We found that: (1) the Congo craton, the Yaoundé domain, the southeastern part of the West Cameroon domain, and the northern part of the Adamawa-Yade domain are characterized by low gravity anomaly. (2) the southern part of the Adamawa-Yade domain is marked by a pronounced E-W trending high gravity anomaly. (3) the crust is thicker beneath the Congo craton, the Yaoundé domain and the southern part of the Adamawa-Yade domain. (4) the presence of a denser lower crust material beneath the southern part of the Adamawa-Yade domain. We propose that this denser crustal material is an under-thrusted portion of the Congo craton that has been densified through metacratonization processes that accompanied collision between the craton and the orogenic terranes. This is in good agreement with geological and geochemical observations indicating that the northern edge of the Congo craton and the Adamawa-Yade domain had undergone metacratonization during the Neoproterozoic. Our suggestion is also in good agreement with observations which show that the margins of many cratons worldwide have been decratonized due to subduction processes. Our work highlights the importance of potential field geophysical

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

    Science.gov (United States)

    Le Gall, Philippe; Chen, Ping-Ping; Nieser, Nico; Guilbert, Eric; Njiokou, Flobert; Marsollier, Laurent; Guégan, Jean-François; Pluot-Sigwalt, Dominique; Eyangoh, Sara; Harry, Myriam

    2016-01-01

    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. PMID:27149077

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

    Science.gov (United States)

    Meyin A Ebong, Solange; Petit, Elsa; Le Gall, Philippe; Chen, Ping-Ping; Nieser, Nico; Guilbert, Eric; Njiokou, Flobert; Marsollier, Laurent; Guégan, Jean-François; Pluot-Sigwalt, Dominique; Eyangoh, Sara; Harry, Myriam

    2016-01-01

    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.

  3. 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.

  4. Impact of Refugees on Local Health Systems: A Difference-in-Differences Analysis in Cameroon.

    Directory of Open Access Journals (Sweden)

    Lambed Tatah

    Full Text Available Hosting refugees may represent a drain on local resources, particularly since external aid is frequently insufficient. Between 2004 and 2011, over 100,000 refugees settled in the eastern border of Cameroon. With little known on how refugee influx affects health services of the hosting community, we investigated the impact of refugees on mother and child health (MCH services in the host community in Cameroon. We used Cameroon's 2004 and 2011 Demographic and Health Surveys to evaluate changes in MCH indicators in the refugee hosting community. Our outcome variables were antenatal care (ANC coverage, caesarean delivery rate, place of delivery and child vaccination coverage; whereas the exposure variable was residence in the refugee hosting community. We used a difference-in-differences analysis to compare indicators of the refugee hosting community to a control group selected through propensity score matching from the rest of the country. A total of 10,656 women were included in our 2004 analysis and 7.6% (n = 826 of them resided in the refugee hosting community. For 2011, 15,426 women were included and 5.8% (n = 902 of them resided in the hosting community. Between 2004 and 2011, both the proportion of women delivering outside health facilities and children not completing DPT3 vaccination in the refugee hosting community decreased by 9.0% (95% Confidence Interval (CI: 3.9-14.1% and 9.6% (95% CI: 7.9-11.3% respectively. However, ANC attendance and caesarean delivery did not show any significant change. Our findings demonstrate that none of the evaluated MCH service indicators deteriorated (in fact, two of them improved: delivery in health facilities and completing DPT3 vaccine with the presence of refugees. This suggests evidence disproving the common belief that refugees always have a negative impact on their hosting community.

  5. 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.

  6. 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

  7. Burns in pregnancy: a case report from Buea Regional Hospital, Cameroon

    Directory of Open Access Journals (Sweden)

    Aimié Thierry Bitang

    2009-12-01

    Full Text Available To the best of our knowledge similar cases of severe burns in pregnancy have not been published in Cameroon; indicating the rarity of this devastating condition and therefore the dilemma that practitioners may be confronted with in its management. This report is to help the Physician understand the factors that should determine his/her management decisions by reviewing the limited literature of burns in pregnancy. A multidisciplinary approach by a team of Obstetricians, Anesthetist/Intensive care Physicians, Pediatricians and Surgeons is indispensible. Adequate resuscitation, fight against sepsis, the gestational age and the severity of the burn will determine the outcome or prognosis.

  8. 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

  9. Determinants of modern contraceptive practice in Yaoundé-Cameroon: a community based cross sectional study.

    Science.gov (United States)

    Njotang, Philip Nana; Yakum, Martin Ndinakie; Ajong, Atem Bethel; Essi, Marie José; Akoh, Ebile Walter; Mesumbe, Nzene Edmond; Ako, Simon; Mbu, Enow Robinson

    2017-06-24

    Despite numerous efforts put in place to increase modern contraceptive use in Cameroon as a means to fight maternal and infant mortality, the prevalence of modern contraception has shown only a slow increase and maternal mortality is constantly rising. This paper attempts to identify barriers to contraceptive use in Biyem-Assi, Yaoundé-Cameroon so as to clearly define in which domain and how to intervene concerning contraceptive use in Cameroon. It was a community-based cross sectional study involving a two-steps cluster sampling. Data were collected from November 2014 to April 2015 and analysis done with Epi-Info version 3.5.4. Association between contraceptive use and independent factors was estimated by calculating odds ratio (OR) and confidence interval at 95%. Significance of association in univariate analysis was estimated by calculating the p value with chi2 test. Potential confounder (pregnancy intention) controlled in a multiple logistic regression. A total of 613 sexually active women were enrolled into the study with a mean age of 27.2 (δ ± 6.2) years. Among the women, 293 (47.8%) were in a union and 530 (86.8%) of them had attended at least a secondary education. Also, 107 (17.5%) responded that their beliefs do not approve contraceptive use and 101 (16.6%) said their partners do not approve contraception. At the moment of data collection, 361 (58.9 [54.9-62.8] %) were currently using a modern contraceptive method. The rate of use of modern contraception was significantly lower in women in a union (OR 0.57, p = 0.0002) and in those with age greater than 30 years (OR 0.45, p = 0.0004). Conversely, the rate of use was significantly higher in women whose partners approved contraception (OR 4.14, p = 0.0000) or when family planning was discussed within the couple (OR 1.93, p = 0.0028). The rate of use of modern contraception in Biyem-Assi Health District is relatively high. Women in a union and those aged greater than 30 years turn to be

  10. Generalized Extreme Value Distribution Models for the Assessment of Seasonal Wind Energy Potential of Debuncha, Cameroon

    OpenAIRE

    Nkongho Ayuketang Arreyndip; Ebobenow Joseph

    2016-01-01

    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 partit...

  11. Weight gain of steers on pastures of cameroon grass and braquiarão grass

    OpenAIRE

    Cláudia de Paula Rezende; José Marques Pereira; Thasia Martins Macedo; Augusto Magno Ferreira Borges; Gleidson Giordano Pinto de Carvalho; Érico de Sa Petit Lobão; Isis Miranda Carvalho Nicory

    2015-01-01

    We evaluate pastures formed of Pennisetum purpureum cv.cameroon and Urochloa brizantha.cv. Marandu aiming at greater live weight gains per animal and per hectare. The animals were crossbred male half blood Tabapuã/Nellore live weight of 280 kg (9.3 kilos). Each grass was submitted to four stocking rates in a rotated grazing system with three days of grazing and 36 days of rest, resulting in a 39 days grazing cycle. In the summer the stocking rates were 2.64, 3.49, 4.34 and 5.09 UA/ha in and w...

  12. 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.

  13. 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

  14. [Effects of volcanic eruptions on human health in Iceland. Review].

    Science.gov (United States)

    Gudmundsson, Gunnar; Larsen, Guðrun

    2016-01-01

    Volcanic eruptions are common in Iceland and have caused health problems ever since the settlement of Iceland. Here we describe volcanic activity and the effects of volcanic gases and ash on human health in Iceland. Volcanic gases expelled during eruptions can be highly toxic for humans if their concentrations are high, irritating the mucus membranes of the eyes and upper respiratory tract at lower concentrations. They can also be very irritating to the skin. Volcanic ash is also irritating for the mucus membranes of the eyes and upper respiratory tract. The smalles particles of volcanic ash can reach the alveoli of the lungs. Described are four examples of volcanic eruptions that have affected the health of Icelanders. The eruption of Laki volcanic fissure in 1783-1784 is the volcanic eruption that has caused the highest mortality and had the greatest effects on the well-being of Icelanders. Despite multiple volcanic eruptions during the last decades in Iceland mortality has been low and effects on human health have been limited, although studies on longterm effects are lacking. Studies on the effects of the Eyjafjallajökul eruption in 2010 on human health showed increased physical and mental symptoms, especially in those having respiratory disorders. The Directorate of Health in Iceland and other services have responded promptly to recurrent volcanic eruptions over the last few years and given detailed instructions on how to minimize the effects on the public health. Key words: volcanic eruptions, Iceland, volcanic ash, volcanic gases, health effects, mortality. Correspondence: Gunnar Guðmundsson, ggudmund@landspitali.is.

  15. 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

  16. Bio-indicator species and Central African rain forest refuges in the Campo-Ma'an area, Cameroon

    NARCIS (Netherlands)

    Tchouto, M.G.P.; de Wilde, J.J.F.E.; de Boer, W.F.; van der Maesen, L.J.G.; Cleef, A.M.

    2009-01-01

    This study aims to examine the geographical position of late Pleistocene forest refuges in the tropical lowland rain forest in southern Cameroon by analysing the distribution of 178 selected bio-indicator species. We studied the distribution patterns of these species, such as strict and narrow

  17. 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

  18. A new species of Colletoecema (Rubiaceae) from southern Cameroon with a discussion of relationships among basal Rubioideae

    NARCIS (Netherlands)

    Sonké, B.; Dessein, S.; Taedoumg, H.; Groeninckx, I.; Robbrecht, E.

    2008-01-01

    Colletoecema magna, a new species from the Ngovayang Massif (southern Cameroon) is described and illustrated. A comparative morphological study illustrates the similar placentation and fruit anatomy of the novelty and Colletoecema dewevrei, the only other species of the genus. Colletoecema magna

  19. Diversity and dynamics of mycorrhizal associations in tropical rain forests with different disturbance regimes in South Cameroon

    NARCIS (Netherlands)

    Onguene, N.A.

    2000-01-01

    The present study documents the occurrence of mycorrhizal associations in the rain forests of south Cameroon. All species investigated are mycorrhizal. Most timber species form arbuscular mycorrhiza, but some timber species, which usually occur in clumps, form ectomycorrhiza. Species

  20. Importance of the ectomycorrhizal network for ectomycorrhiza formation and seedling survival in rain forests of South Cameroon

    NARCIS (Netherlands)

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

    2002-01-01

    An investigation was undertaken at two sites in south Cameroon to assess the importance of living roots of adult trees as sources of inoculum for survival, ectomycorrhizal colonisation and growth of seedlings of Paraberlinia bifoliolata. One-month-old seedlings of Paraberlinia bifoliolata, isolated

  1. 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

  2. Soil macrofauna community structure along a gradient of land use intensification in the humid forest zone of southern Cameroon.

    NARCIS (Netherlands)

    Madong à Birang,

    2004-01-01

    The impact of land use systems on soil macrofauna community structures is described as well as their relationships with the vegetation and soil parameters in the humid forest zone of southernCameroon

  3. 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,…

  4. Global References, Local Translation: Adaptation of the Bologna Process Degree Structure and Credit System at Universities in Cameroon

    Science.gov (United States)

    Eta, Elizabeth Agbor; Vubo, Emmanuel Yenshu

    2016-01-01

    This article uses temporal comparison and thematic analytical approaches to analyse text documents and interviews, examining the adaptation of the Bologna Process degree structure and credit system in two sub-systems of education in Cameroon: the Anglo-Saxon and the French systems. The central aim is to verify whether such adaptation has replaced,…

  5. The neglected burden of snakebites in Cameroon: a review of the epidemiology, management and public health challenges.

    Science.gov (United States)

    Tochie, Joel Noutakdie; Temgoua, Mazou N; Njim, Tsi; Celestin, Danwang; Tankeu, Ronni; Nkemngu, Njinkeng J

    2017-08-14

    Snakebite is an underestimated medical and surgical emergency in developing countries responsible for a high disease burden. Optimal management of snake envenomation in these resource-limited settings is precluded by several public health challenges. In this review, we discuss the disease burden of snakebites in Cameroon and the public health challenges of its management in view of making recommendations essential for policy-making. MEDLINE, African Journals Online and Google Scholar were searched from January 1990 to February 2017 for studies addressing snakebite in Cameroon. Our search extended to include grey literature from book chapters, conference proceedings, theses and documents from organizations. Our results suggest that snakebites pose a significant health and economic burden in Cameroon. A composite of factors contributes to the challenge of managing snakebites in Cameroon and include: inadequate disease surveillance; poor health-seeking behaviours of patients; under-production and scarcity of anti-venom serum and the relatively high cost of anti-venom serum. There is an urgent need to revamp the current health policies through health education, promotion and building of sustainable health systems. Disease surveillance and management can be improved by providing refresher courses for healthcare providers and subsidization of the prices of anti-venom serum in pharmacies in the country.

  6. Diversity patterns in the flora of the Campo-Ma'an rain forest, Cameroon: do tree species tell it all?

    NARCIS (Netherlands)

    Tchouto, M.G.P.; Boer, de W.F.; Wilde, de J.J.F.E.; Maesen, van der L.J.G.

    2006-01-01

    This study describes diversity patterns in the flora of the Campo-Ma¿an rain forest, in south Cameroon. In this area, the structure and composition of the forests change progressively from the coastal forest on sandy shorelines through the lowland evergreen forest rich in Caesalpinioideae with

  7. The soils of the lower eastern slopes of the Cameroon mountain and their suitability for various perennial crops

    NARCIS (Netherlands)

    Hasselo, H.N.

    1961-01-01

    On the eastern slopes of the Cameroon Mountains soils occurring below the 100- metre contour were surveyed on a scale 1:25,000. Most soils are young marine clay soils used for growing bananas, oilpalms, cocoa, rubber and tea. At some places there are lava streams from the mountains.

    A more

  8. Curriculum development at the Regional African Wildlife Colleges, with special reference to the Ecole de Faune (Cameroon)

    NARCIS (Netherlands)

    Scholte, P.

    2003-01-01

    Regional colleges in Tanzania, Cameroon and, recently, South Africa have trained some 4000 wildlife managers. Training need assessments called for major curriculum reforms, which were developed and implemented in the late 1990s. This is an analysis of the factors that influenced this curriculum

  9. 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.

  10. 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.

  11. 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

  12. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  14. Barriers to counselling support for HIV/AIDS patients in south-western Cameroon.

    Science.gov (United States)

    Fonchingong, Charles C; Mbuagbo, Timothy O; Abong, Jennifer T

    2004-11-01

    The potential synergy between counselling and HIV/AIDS prevention is gaining recognition in Cameroon as counselling sessions are more often organised at health centres. In order to evaluate the actual achievements of these efforts, a qualitative ethnographic survey (based on interviews and focus group discussions) was conducted in two public and two private hospitals in the South-West Province. Churches and public health officials in Cameroon are struggling with the psycho-social, philosophical, psychological, theological, social, moral, ethical and cultural dimensions of HIV/AIDS, as they seek out viable prevention strategies. Health centres are also struggling to embrace the full meaning of counselling and to make psychological and spiritual support to AIDS patients available through the centres. Patients using these health centres may receive HIV testing against a backdrop of cultural standards that allow unsafe sex and bar open discussion on sex and sexuality. We propose that reversing the trend of the epidemic requires the intervention of the State, organisations in civil society and the family. Equally crucial is the role played by the churches - especially in confronting issues of stigmatisation and abandonment that often accompany patient disclosure, and in providing spiritual, emotional and psychological support to patients undergoing treatment.

  15. 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.

  16. 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.

  17. Genetic analysis of hepatitis A virus variants circulating among children presenting with acute diarrhea in Cameroon.

    Science.gov (United States)

    Forbi, Joseph C; Agwale, Simon M; Ndip, Lucy M; Esona, Mathew D

    2012-05-01

    Molecular investigation was undertaken of circulating hepatitis A virus (HAV) associated with cases of acute diarrhea among children under 5 years of age in Kumba-Cameroon. Reverse transcription PCR, sequencing, and phylogenetic analysis of a 371 bp segment of the VP1/P2A junction of six isolates obtained from stool samples showed the exclusive emergence of genetically related HAV subgenotype IA. All the isolates clustered within a unique lineage exhibiting a 99.5% nucleotide identity suggesting infection from a common source. The Cameroonian HAV isolates did not intermix or cluster with those from other regions of Africa and the rest of the world. Tajima's neutralization tests using the six sequences suggested HAV/IA population expansion (D = -1.37; P = 0.016). This is the first description of indigenous HAV genotypes circulating in Cameroon revealing a community-wide spread and predominance of HAV/1A infection in the Kumba area. These findings stress the need for routine molecular tracking of HAV infection as a contributory cause of acute diarrhea in Cameroonian children. Copyright © 2012 Wiley Periodicals, Inc.

  18. Konzo outbreak among refugees from Central African Republic in Eastern region, Cameroon.

    Science.gov (United States)

    Ciglenečki, I; Eyema, R; Kabanda, C; Taafo, F; Mekaoui, H; Urbaniak, V

    2011-03-01

    Konzo is a spastic paraparesis of sudden onset, linked to the exclusive consumption of insufficiently processed bitter cassava as staple food combined with low protein intake. Around 60,000 refugees from the Central African Republic sought refuge in villages in eastern Cameroon between 2005 and 2007. Médecins Sans Frontières was providing nutritional and medical assistance in the villages affected by displacement. We describe cases of konzo seen at the mobile clinics organized in these villages. Basic information including demographic data, history and clinical presentation was recorded for each konzo patient. All patients were given nutritional supplements, and selected cases were referred for physiotherapy to a rehabilitation center. A total of 469 patients were diagnosed with konzo. The majority (80%) were refugees. Children and women of reproductive age predominated. Most of the patients developed symptoms after 2007 in a seasonal pattern with most of the cases occurring during the dry winter season. Most of the patients complained about walking difficulties and weight loss and had exaggerated lower limb reflexes and muscle wasting on observation. Eastern Cameroon is an area with konzo. More effort needs to be put into preventive and educational measures. In addition, timely balanced food rations have to be provided to refugees. Copyright © 2010 Elsevier Ltd. All rights reserved.

  19. Evaluation of New Tools for Malaria Vector Control in Cameroon: Focus on Long Lasting Insecticidal Nets

    Science.gov (United States)

    Etang, Josiane; Nwane, Philippe; Piameu, Michael; Manga, Blaise; Souop, Daniel; Awono-Ambene, Parfait

    2013-01-01

    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. PMID:24086399

  20. Logging Concessions and Local Livelihoods in Cameroon: from Indifference to Alliance?

    Directory of Open Access Journals (Sweden)

    Guillaume Lescuyer

    2012-03-01

    Full Text Available Sustainable forest management gives the opportunity to better integrate the way local populations use their customary "village terroirs" in the logging activities. This requirement is explicitly stated in all forest laws of the Congo Basin countries but its implementation on the field remains under documented. In Cameroon, 30 forest management plans (FMP for logging concessions have been reviewed to assess how they effectively include customary use rights. The integration of use rights into the FMPs is heterogeneous but always with very low enforcement. The weak influence of the FMP application on local practices is confirmed with an empirical survey that shows that natural, financial, and physical capitals in two villages of the eastern region of Cameroon have been little affected by the adjoining logging concession over the latest 13 years. Extrasector policies such as agriculture, road infrastructure, techniques, and land tenure are the real drivers of socioeconomic change at the local scale. Their impacts are facilitated by the presence of the logging concessions, which can contribute indirectly to improve local livelihoods.

  1. 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.

  2. Molecular assessment of the bacterial community associated with Cassava (Manihot esculenta Crantz) cultivation in Cameroon.

    Science.gov (United States)

    Sarr, Papa Saliou; Sugiyama, Akifumi; Begoude, Aime Didier Boyogueno; Yazaki, Kazufumi; Araki, Shigeru; Nawata, Eiji

    2017-04-01

    Bacterial communities play an important role in nutrient cycles and plant development. Their distribution and activity may depend on location and environmental heterogeneity. This study characterized soil bacterial communities in cassava fields of Eastern (Andom) and Southern (Bityili) Cameroon using molecular tools. In both sites, two improved varieties (TMS-96/1414; TMS-92/0326) and a local variety (Local) were grown in a randomized block design. Composite bulk soils were collected at 10months after planting from cassava plots. The 16S rDNA region was amplified, MiSeq was performed and sequence data analyzed. The same 17 bacterial phyla were present in both Andom and Bityili, while Chlorobi and Deinococcus-Thermus were only specific to Andom. The phyla Proteobacteria, Planctomycetes, Actinobacteria and Acidobacteria were dominant. Although both sites shared similar phyla, the principal coordinate analysis revealed significant variations in their composition, suggesting that the functions of the bacteria in nutrients cycling are likely to differ between Andom and Bityili. Cassava yields were generally higher in Andom which also displayed a higher diversity of bacterial communities. This study provides useful information on the composition of bacterial communities in cassava fields in two agro-ecologies of Cameroon. It constitutes to our knowledge the first report describing soil bacterial communities in association with cassava growth in the country, using molecular tools. Copyright © 2017 Elsevier GmbH. All rights reserved.

  3. 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.

  4. Addressing health workforce distribution concerns: a discrete choice experiment to develop rural retention strategies in Cameroon.

    Science.gov (United States)

    Robyn, Paul Jacob; Shroff, Zubin; Zang, Omer Ramses; Kingue, Samuel; Djienouassi, Sebastien; Kouontchou, Christian; Sorgho, Gaston

    2015-03-01

    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. 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. Among medical and nursing students a rural retention bonus of 75% of base salary (aOR= 8.27, 95% CI: 5.28-12.96, Pworker cadre for all the attributes. Preference impact measurements were also estimated to identify combination of incentives that health workers would find most attractive. 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 the analysis of locally relevant, actionable incentives, generated through the involvement of policy-makers at the design stage, this study provides an example of research directly linked to policy action to address a vitally important issue in global health.

  5. Epidemiology of sudden cardiac death in Cameroon: rationale and design of the Douala-SUD survey.

    Science.gov (United States)

    Bonny, Aimé; Noah, Dominique Noah; Ngantcha, Marcus; Ateh, Robinson; Saka, Cécile; Wa, Jonas; Fonga, Réné; Amougou, Sylvie Ndongo; Gregers Winkel, Bo; Lambiase, Pier; Priori, Silvia G

    2014-01-01

    The burden of sudden unexplained death in sub-Saharan Africa is unknown. The aim of this study is to establish the epidemiology of sudden cardiac death in Cameroon. The Douala sudden unexplained death (Douala-SUD) study is a prospective, multiple-source, community-based surveillance of all cases of unexpected death (15 years. After approval from institutional boards, all deaths occurring in residents of four areas of Douala city will be checked for circumstances of death and past medical history. Subjects who die naturally will be further investigated. Unexpected death victims will be checked for detailed demographic, clinical, electrocardiographic, echocardiographic and biological records. Autopsy background and genetic analysis (postmortem or in first relatives if the young victim is aged<40 years) will be performed as far as possible. Finally, the use of cardiopulmonary resuscitation efforts during the timeframe of sudden cardiac arrest will also be evaluated. The Douala-SUD study will provide comprehensive, contemporary data on the epidemiology of sudden unexplained and cardiac death in sub-Saharan Africa and will help in the development of strategies to prevent and manage cardiac arrest in Cameroon as well as in other sub-Saharan countries. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  6. [Gender and sexuality in young people at Bafoussam and Mbalmayo, Cameroon].

    Science.gov (United States)

    Jean-Robert, Rwenge Mburano

    2004-08-01

    Gender and sexuality of youths in Bafoussam and Mbalmayo, Cameroon. This paper outlines, while resorting to the gender perspective, the social factors that predispose youths to risky sexual practices using data from a survey of culture, gender, sexual behaviour and STD/AIDS carried out in Cameroon, at Bafoussam (Bamileke area) and Mbalamayo (Bëti area). Analysis revealed that the ideology of masculinity and feminity prevail in the populations studied, but in the Bamileke group, where gender system is unfavourable to women, young people adhere less to these ideologies than their parents. Our data also revealed that the level of the knowledge of the modes of transmission of STD/AIDS and the degree of acceptability of condoms in this group are higher among boys than girls. The young Bëti were more inclined to take risks in sexual activities than the Bamileke. It was equally found that boys were more inclined than girls to be unfaithful to their regular partners, while the boys were more inclined to use condoms than girls. Finally, our data revealed that age and other characteristics of the regular sexual partners of young people influence, among others, the probability of being engaged in risky sex especially among girls. Health education and information programmes can be improved amongst these youth populations by taking into account the totality of these elements.

  7. 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.

  8. 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.

  9. 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.

  10. Taos Plateau Volcanic Project: A Vehicle for Integration of Concepts in Igneous Petrology

    Science.gov (United States)

    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.

  11. Sustaining Volcanism of the Klyuchevskoy Group

    Science.gov (United States)

    Nikulin, A.; Levin, V. L.; Carr, M. J.; Herzberg, C. T.; West, M. E.

    2011-12-01

    A primary control on the geographic position of volcanic arcs is the depth of fluid release from the subducting plate beneath the arc. Volcanoes of the Klyuchevskoy Group in Eastern Russia comprise the most active volcanic arc system in the world with the depth of the subducting Pacific plate beneath the arc estimated at 180-200km, greatly in excess of the global average. We attribute this deviation to a presence of a secondary melt generation source beneath this arc and present geophysical, geochemical and petrological evidence in support of this hypothesis. We present seismological constraints based on receiver function migration on the upper mantle structure beneath the Klyuchevskoy Group. We identify a sharply bounded low-velocity seismic feature at ~110 km depth separated from the subducting Pacific Plate. Analysis of open-access geochemical databases yields a previously unnoted bi-modal distribution of Zr/Nb concentrations in the Klyuchevskoy Group lavas. If the Zr/Nb ratio has some sensitivity for the depth to the slab, as it appears to in Central America, the observed bi-modal distribution of Zr/Nb values within lavas of the Klyuchevskoy Group may be associated with two sources, a deep source and a shallower source with higher Zr/Nb. Results of petrological modeling of melting conditions inferred from unfractionated basalt indicate melting pressures consistent with a source at a depth shallower than the estimated depth to the subducting plate. Inferred pressures of initial melting indicate a depth of about 70 to 90 km depth, roughly consistent with the position of the low -velocity seismic anomaly. We hypothesize that this upper mantle structure may serve as a second source of melts driving volcanism of the Klyuchevskoy Group. Presence of such source may explain both the extraordinary productivity of this volcanic arc and its unusual location.

  12. Volcanic disasters and incidents: A new database

    Science.gov (United States)

    Witham, C. S.

    2005-12-01

    A new database on human mortality and morbidity, and civil evacuations arising from volcanic activity is presented. The aim is to quantify the human impacts of volcanic phenomena during the 20th Century. Data include numbers of deaths, injuries, evacuees and people made homeless, and the nature of the associated volcanic phenomena. The database has been compiled from a wide range of sources, and discrepancies between these are indicated where they arise. The quality of the data varies according to the source and the impacts reported. Data for homelessness are particularly poor and effects from ashfall and injuries appear to be under-reported. Of the 491 events included in the database, ˜53% resulted in deaths, although the total death toll of 91,724 is dominated by the disasters at Mt Pelée and Nevado del Ruiz. Pyroclastic density currents account for the largest proportion of deaths, and lahars for the most injuries incurred. The Philippines, Indonesia, and Southeast Asia, as a region, were the worst affected, and middle-income countries experienced greater human impacts than low or high-income countries. Compilation of the database has highlighted a number of problems with the completeness and accuracy of the existing CRED EM-DAT disaster database that includes volcanic events. This database is used by a range of organisations involved with risk management. The new database is intended as a resource for future analysis and will be made available via the Internet. It is hoped that it will be maintained and expanded.

  13. 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

  14. 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.

  15. UNAVCO Conference explores advances in volcanic geodesy

    Science.gov (United States)

    Stein, Seth; Hamburger, Michael; Meertens, Charles; Dixon, Timothy; Owen, Susan

    Volcanic eruptions are among Earth's most spectacular surface phenomena. However, attempts to understand their basic physics face the challenge that the key processes occur at great depth and are difficult to observe. Thus volcanologists have been interested for years in using ground deformation measurements to study active volcanoes and predict their behavior during extended volcanic crises, such as the dramatic six weeks in 1980 between the initial and major eruptions of Mt. Saint Helens.The advent of new technologies in recent years—in particular the Global Positioning System (GPS) and Interferometric Synthetic Aperture Radar (INSAR)—has shown potential for significant advances in volcano studies. Progress in this direction was explored at a conference organized by the University Navstar Consortium (UNAVCO) on September 15-17, 1999, with financial support from the National Science Foundation (NSF), NASA, and the U.S. Geological Survey (USGS). The meeting aimed to assess the status of various geodetic technologies and their potential to address crucial scientific and social needs in volcanic science and monitoring, as well as to develop recommendations on ways to spur further progress in these areas.

  16. Amazonian volcanism inside Valles Marineris on Mars

    Science.gov (United States)

    Brož, Petr; Hauber, Ernst; Wray, James J.; Michael, Gregory

    2017-09-01

    The giant trough system of Valles Marineris is one of the most spectacular landforms on Mars, yet its origin is still unclear. Although often referred to as a rift, it also shows some characteristics that are indicative of collapse processes. For decades, one of the major open questions was whether volcanism was active inside the Valles Marineris. Here we present evidence for a volcanic field on the floor of the deepest trough of Valles Marineris, Coprates Chasma. More than 130 individual edifices resemble scoria and tuff cones, and are associated with units that are interpreted as lava flows. Crater counts indicate that the volcanic field was emplaced sometime between ∼0.4 Ga and ∼0.2 Ga. The spatial distribution of the cones displays a control by trough-parallel subsurface structures, suggesting magma ascent in feeder dikes along trough-bounding normal faults. Spectral data reveal an opaline-silica-rich unit associated with at least one of the cones, indicative of hydrothermal processes. Our results point to magma-water interaction, an environment of astrobiological interest, perhaps associated with late-stage activity in the evolution of Valles Marineris, and suggest that the floor of Coprates Chasma is promising target for the in situ exploration of Mars.

  17. Geothermal and volcanism in west Java

    Science.gov (United States)

    Setiawan, I.; Indarto, S.; Sudarsono; Fauzi I, A.; Yuliyanti, A.; Lintjewas, L.; Alkausar, A.; Jakah

    2018-02-01

    Indonesian active volcanoes extend from Sumatra, Jawa, Bali, Lombok, Flores, North Sulawesi, and Halmahera. The volcanic arc hosts 276 volcanoes with 29 GWe of geothermal resources. Considering a wide distribution of geothermal potency, geothermal research is very important to be carried out especially to tackle high energy demand in Indonesia as an alternative energy sources aside from fossil fuel. Geothermal potency associated with volcanoes-hosted in West Java can be found in the West Java segment of Sunda Arc that is parallel with the subduction. The subduction of Indo-Australian oceanic plate beneath the Eurasian continental plate results in various volcanic products in a wide range of geochemical and mineralogical characteristics. The geochemical and mineralogical characteristics of volcanic and magmatic rocks associated with geothermal systems are ill-defined. Comprehensive study of geochemical signatures, mineralogical properties, and isotopes analysis might lead to the understanding of how large geothermal fields are found in West Java compared to ones in Central and East Java. The result can also provoke some valuable impacts on Java tectonic evolution and can suggest the key information for geothermal exploration enhancement.

  18. 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.

  19. 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

  20. 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

    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. 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. 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 non-existent at the levels

  1. Global volcanic emissions: budgets, plume chemistry and impacts

    Science.gov (United States)

    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.

  2. Long-lived but Discontinuous Hotspot Volcanism of the South Pacific Mantle

    Science.gov (United States)

    Koppers, A.; Staudigel, H.; Wijbrans, J.; Pringle, M.

    2001-12-01

    Hotspots of the South Pacific have been operating since the Early Cretaceous. We present evidence that their heterogeneous geochemical character and, hence, their respective HIMU-EMI-EMII mantle sources, can be traced back into the West Pacific Seamount Province (WPSP) using plate tectonic reconstructions. This implies that the HIMU, EMI and EMII mantle components are enduring features within the Earth's mantle, at least, for the last 140 Myr. These correlations are eminent on the scale of the WPSP and the South Pacific Thermal and Isotopic Anomaly (SOPITA) although the evolution of individual hotspots emerges notably more complicated. Hotspots in the WPSP and SOPITA mantle regions typically display intermittent volcanic activity, longevities shorter than 70 Myr, superposition of hotspot volcanism, and indirectly the motion of their mantle plumes through time. In our plate tectonic reconstructions, we use 40Ar/39Ar seamount ages and Sr-Nd-Pb isotopic signatures to map out Cretaceous hotspot volcanism in the WPSP and to characterize its evolution with respect to the currently active hotspots in the SOPITA region. EM-type Magellan, Anewetak, Ralik and Ratak seamount trails can be traced back to the magmatic activity of the Macdonald, Rurutu and Rarotonga hotspots during the Cretaceous; the HIMU-type seamounts within the Southern Wake seamount trail (97-120 Ma) most likely originated from the Mangaia-Rurutu "hot-line" in the Cook-Austral Islands. The Typhoon and Japanese guyots terminated their volcanism during the Early Cretaceous and have no presently active hot spot. However, the currently active Samoan, Society, Pitcairn and Marquesas hotspots may be traced back only to about 30-70 Myr and lack long-lived counterparts in the WPSP. These hotspots may have become active over the last 30-70 Myr only. All in all hotspot volcanism in the South Pacific seems to be controlled by a "superplume" type of mantle convection giving rise to multiple weak mantle plumes, each

  3. Experimental Constraints on the Respiratory Health Hazard Posed by Crystalline Silica-bearing Volcanic Ash

    Science.gov (United States)

    Damby, D. E.; Horwell, C. J.; Baxter, P. J.

    2016-12-01

    Since volcanic ash from the 1980 eruption of Mount St Helens, USA, impacted on a million inhabitants in the Pacific Northwest, it is known that a substantial fraction of volcanic ejecta is respirable and therefore capable of being a human health hazard. Exacerbation of airway problems, such as asthma and chronic bronchitis, due to an increase in ambient particulate matter following the eruption, was an expected finding; however, a significant amount of cristobalite, a toxic mineral, in the ash was unforeseen and led to repeated toxicological testing of the ash to establish the hazard posed to human health. Those results together with studies on cristobalite-bearing ash from other major eruptions suggest that volcanic cristobalite is minimally reactive relative to pure phase standards. This finding adheres to a well-established thesis on the variable pathogenicity of crystalline silica, whereby intrinsic characteristics and extrinsic modifications of the crystalline silica govern reactivity. Indeed, chemical impurities (up to 4 wt% aluminum) and substantial structural defects have been implicated in the reduced potency of volcanic cristobalite. However, whilst not overtly toxic, volcanic ash exposure can initiate a sample-dependent inflammatory response in macrophages, a cell type that provides a first line of defense against inhaled particles. Inflammation plays a pivotal role in crystal-driven disease progression and can be observed in patients with particle-induced lung disease. We demonstrate that ash can induce inflammation by stimulating the NLRP3 inflammasome, a cytosolic receptor complex that drives the inflammatory response to several endo- and exogenous crystalline materials. The impact of inflammasome activation mediated by inhaled ash particles and its potential relevance in chronic pulmonary diseases was confirmed in primary human cells; however, it is not yet known whether the response resolves in vivo. The NLRP3 inflammasome as an ash

  4. Prevalence, correlates and pattern of Hepatitis B among antenatal clinic attenders in Yaounde-Cameroon: is perinatal transmission of HBV neglected in Cameroon?

    Science.gov (United States)

    2013-01-01

    Background Few studies have evaluated the prevalence of HBV in the general Cameroonian population or among antenatal attendants. The aim of this study was to determine the prevalence, correlates and patterns of Hepatitis B surface antigen among pregnant women attending antenatal care in Yaounde-Cameroon. Methods This was a cross-sectional multicenter study carried out in a referral hospital and two secondary hospitals in Yaounde, the capital of Cameroon. The study lasted 15 months (March 2011 to June 2012), and recruited 959 pregnant women. Patient recruitment was consecutive. The HBsAg was tested using the Monalisa HBsAg Ultra ELISA kit. Other hepatitis B markers were equally tested. We used the statistical package for social sciences (SPSS) version 14.0 software to conduct a quantitative analysis of the derived data. Simple descriptive statistics such as means, standard deviations, and proportions were used to describe the data. We tested for association in categorical variables using the chi-squared (χ2) test. The odds ratio (OR) and the corresponding 95% confidence intervals (95% CI) were used to summarise the strength of association between specific binary exposure and outcome variables. The level of statistical significance for the study was set at p hepatitis B infection (HBsAg) among antenatal clinic attenders in our setting was 7.7%. Amongst these women, just 5.4% were previously aware of their HBsAg status. The rate of HBV infectivity was high, with 28% of HBsAg positive women having evidence of HBeAg in their plasma, and up to 45.8% of these women lacking antibodies against hepatitis B e antigen (anti-HBe). About 41% of the pregnant women had had previous contact with HBV as evidenced by the positive status for anti-HBc. Just 2.7% of the pregnant women had previously been vaccinated against HBV. The mean age for HBsAg positivity in our setting was 26.9 ±4.7 years, and the most affected age group was the 25 – 29 years age group. There was no

  5. Analysis of concentration patterns in volcanic rocks: Insights into dynamics of highly explosive volcanic eruptions

    Science.gov (United States)

    Perugini, D.; Petrelli, M.; Poli, G.

    2006-10-01

    In this contribution we present new data resulting from the analysis of concentration patterns of mixed juvenile fragments ejected by a highly explosive volcanic eruption that occurred on Salina Island (Aeolian Islands, Italy) and our aim is to identify the fluid-dynamic regime characterizing the magma mixing process. Concentration patterns are studied by calculating the power spectrum of concentration variability along transects crossing the magma mixing structures. Results indicate that the slope of power spectrum has an average value of about -5/3, according to Kolmogorov law of turbulence, and suggest that the magma mixing process, in the studied conditions, can be approximated by considering the passive scalar mixing hypothesis in homogeneous isotropic turbulent flow. These results represent a first step towards a better understanding of magma mixing processes associated to highly explosive volcanic eruptions and this first step is taken by studying concentration patterns in volcanic rocks by coupling petrological and non-linear dynamics methods.

  6. Short-lived and discontinuous intraplate volcanism in the South Pacific: Hot spots or extensional volcanism?

    Science.gov (United States)

    Koppers, Anthony A. P.; Staudigel, Hubert; Pringle, Malcolm S.; Wijbrans, Jan R.

    2003-10-01

    South Pacific intraplate volcanoes have been active since the Early Cretaceous. Their HIMU-EMI-EMII mantle sources can be traced back into the West Pacific Seamount Province (WPSP) using plate tectonic reconstructions, implying that these distinctive components are enduring features within the Earth's mantle for, at least, the last 120 Myr. These correlations are eminent on the scale of the WPSP and the South Pacific Thermal and Isotopic Anomaly (SOPITA), but the evolution of single hot spots emerges notably more complicated. Hot spots in the WPSP and SOPITA mantle regions typically display intermittent volcanic activity, longevities shorter than 40 Myr, superposition of hot spot volcanism, and motion relative to other hot spots. In this review, we use 40Ar/39Ar seamount ages and Sr-Nd-Pb isotopic signatures to map out Cretaceous volcanism in the WPSP and to characterize its evolution with respect to the currently active hot spots in the SOPITA region. Our plate tectonic reconstructions indicate cessation of volcanism during the Cretaceous for the Typhoon and Japanese hot spots; whereas the currently active Samoan, Society, Pitcairn and Marquesas hot spots lack long-lived counterparts in the WPSP. These hot spots may have become active during the last 20 Myr only. The other WPSP seamount trails can be only "indirectly" reconciled with hot spots in the SOPITA region. Complex age distributions in the Magellan, Anewetak, Ralik and Ratak seamount trails would necessitate the superposition of multiple volcanic trails generated by the Macdonald, Rurutu and Rarotonga hot spots during the Cretaceous; whereas HIMU-type seamounts in the Southern Wake seamount trail would require 350-500 km of hot spot motion over the last 100 Myr following its origination along the Mangaia-Rurutu "hotline" in the Cook-Austral Islands. These observations, however, violate all assumptions of the classical Wilson-Morgan hot spot hypothesis, indicating that long-lived, deep and fixed mantle

  7. Ecological niche modelling of Hemipteran insects in Cameroon; the paradox of a vector-borne transmission for Mycobacterium ulcerans, the causative agent of Buruli ulcer.

    Science.gov (United States)

    Carolan, Kevin; Ebong, Solange Meyin A; Garchitorena, Andres; Landier, Jordi; Sanhueza, Daniel; Texier, Gaëtan; Marsollier, Laurent; Gall, Philipe Le; Guégan, Jean-François; Lo Seen, Danny

    2014-10-25

    The mode of transmission of the emerging neglected disease Buruli ulcer is unknown. Several potential transmission pathways have been proposed, such as amoebae, or transmission through food webs. Several lines of evidence have suggested that biting aquatic insects, Naucoridae and Belostomatidae, may act as vectors, however this proposal remains controversial. Herein, based on sampling in Cameroon, we construct an ecological niche model of these insects to describe their spatial distribution. We predict their distribution across West Africa, describe important environmental drivers of their abundance, and examine the correlation between their abundance and Buruli ulcer prevalence in the context of the Bradford-Hill guidelines. We find a significant positive correlation between the abundance of the insects and the prevalence of Buruli ulcer. This correlation changes in space and time, it is significant in one Camerounese study region in (Akonolinga) and not other (Bankim). We discuss notable environmental differences between these regions. We interpret the presence of, and change in, this correlation as evidence (though not proof) that these insects may be locally important in the environmental persistence, or transmission, of Mycobacterium. ulcerans. This is consistent with the idea of M. ulcerans as a pathogen transmitted by multiple modes of infection, the importance of any one pathway changing from region to region, depending on the local environmental conditions.

  8. Trypanosoma brucei Inhibition by Essential Oils from Medicinal and Aromatic Plants Traditionally Used in Cameroon (Azadirachta indica, Aframomum melegueta, Aframomum daniellii, Clausena anisata, Dichrostachys cinerea and Echinops giganteus).

    Science.gov (United States)

    Kamte, Stephane L Ngahang; Ranjbarian, Farahnaz; Campagnaro, Gustavo Daniel; Nya, Prosper C Biapa; Mbuntcha, Hélène; Woguem, Verlaine; Womeni, Hilaire Macaire; Ta, Léon Azefack; Giordani, Cristiano; Barboni, Luciano; Benelli, Giovanni; Cappellacci, Loredana; Hofer, Anders; Petrelli, Riccardo; Maggi, Filippo

    2017-07-06

    Essential oils are complex mixtures of volatile components produced by the plant secondary metabolism and consist mainly of monoterpenes and sesquiterpenes and, to a minor extent, of aromatic and aliphatic compounds. They are exploited in several fields such as perfumery, food, pharmaceutics, and cosmetics. Essential oils have long-standing uses in the treatment of infectious diseases and parasitosis in humans and animals. In this regard, their therapeutic potential against human African trypanosomiasis (HAT) has not been fully explored. In the present work, we have selected six medicinal and aromatic plants ( Azadirachta indica , Aframomum melegueta , Aframomum daniellii , Clausena anisata , Dichrostachys cinerea , and Echinops giganteus ) traditionally used in Cameroon to treat several disorders, including infections and parasitic diseases, and evaluated the activity of their essential oils against Trypanosma brucei TC221. Their selectivity was also determined with Balb/3T3 (mouse embryonic fibroblast cell line) cells as a reference. The results showed that the essential oils from A. indica , A . daniellii , and E. giganteus were the most active ones, with half maximal inhibitory concentration (IC 50 ) values of 15.21, 7.65, and 10.50 µg/mL, respectively. These essential oils were characterized by different chemical compounds such as sesquiterpene hydrocarbons, monoterpene hydrocarbons, and oxygenated sesquiterpenes. Some of their main components were assayed as well on T. brucei TC221, and their effects were linked to those of essential oils.

  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

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    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. 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.

  11. 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.

  12. Charletonia cameroonensis Haitlinger & Kekeunou sp. nov. and the first record of C. justynae Haitlinger, 1987 (Acari: Erythraeidae) from Cameroon with redescription of the species.

    Science.gov (United States)

    Haitlinger, Ryszard; Kekeunou, Sévilor; Lupicki, Dariusz

    2014-01-30

    Charletonia cameroonensis Haitlinger & Kekeunou sp. nov. is described and illustrated from larvae obtained from Zonocerus variegatus (Linnaeus, 1758) (Orthoptera: Pyrgomorphidae) in Cameroon. For the first time C. justynae Haitlinger, 1987 is reported from Cameroon and from Z. variegatus and Eupezus rufipes Quedenfeldt, 1885 (Coleoptera: Tenebrionidae). This paper also presents new morphological data and a range of metric and meristic data for C. justynae. Distribution and hosts of Charletonia found on Orthoptera are given.

  13. The population genetics of wild chimpanzees in Cameroon and Nigeria suggests a positive role for selection in the evolution of chimpanzee subspecies.

    Science.gov (United States)

    Mitchell, Matthew W; Locatelli, Sabrina; Ghobrial, Lora; Pokempner, Amy A; Sesink Clee, Paul R; Abwe, Ekwoge E; Nicholas, Aaron; Nkembi, Louis; Anthony, Nicola M; Morgan, Bethan J; Fotso, Roger; Peeters, Martine; Hahn, Beatrice H; Gonder, Mary Katherine

    2015-01-21

    Chimpanzees (Pan troglodytes) can be divided into four subspecies. Substantial phylogenetic evidence suggests that these subspecies can be grouped into two distinct lineages: a western African group that includes P. t. verus and P. t. ellioti and a central/eastern African group that includes P. t. troglodytes and P. t. schweinfurthii. The geographic division of these two lineages occurs in Cameroon, where the rages of P. t. ellioti and P. t. troglodytes appear to converge at the Sanaga River. Remarkably, few population genetic studies have included wild chimpanzees from this region. We analyzed microsatellite genotypes of 187 wild, unrelated chimpanzees, and mitochondrial control region sequencing data from 604 chimpanzees. We found that chimpanzees in Cameroon and eastern Nigeria comprise at least two, and likely three populations. Both the mtDNA and microsatellite data suggest that there is a primary separation of P. t. troglodytes in southern Cameroon from P. t. ellioti north and west of the Sanaga River. These two populations split ~200-250 thousand years ago (kya), but have exchanged one migrant per generation since separating. In addition, P. t. ellioti consists of two populations that split from one another ~4 kya. One population is located in the rainforests of western Cameroon and eastern Nigeria, whereas the second population appears to be confined to a savannah-woodland mosaic in central Cameroon. Our findings suggest that there are as many as three genetically distinct populations of chimpanzees in Cameroon and eastern Nigeria. P. t. troglodytes in southern Cameroon comprises one population that is separated from two populations of P. t. ellioti in western and central Cameroon, respectively. P. t. ellioti and P. t. troglodytes appear to be characterized by a pattern of isolation-with-migration, and thus, we propose that neutral processes alone can not explain the differentiation of P. t. ellioti and P. t. troglodytes.

  14. Transform Tectonics and Non-Volcanic Oceanic Islands

    OpenAIRE

    Palmiotto, Camilla

    2014-01-01

    Oceanic islands can be divided, according to their origin, in volcanic and tectonic. Volcanic islands are due to excess volcanism. Tectonic islands are mainly formed due to vertical tectonic motions of blocks of oceanic lithosphere along transverse ridges flanking transform faults at slow and ultraslow mid-ocean ridges. Vertical tectonic motions are due to a reorganization of the geometry of the transform plate boundary, with the transition from a transcurrent tectonics to a transtensive and/...

  15. Role of volcanic forcing on future global carbon cycle

    OpenAIRE

    J. F. Tjiputra; O. H. Otterå

    2011-01-01

    Using a fully coupled global climate-carbon cycle model, we assess the potential role of volcanic eruptions on future projection of climate change and its associated carbon cycle feedback. The volcanic-like forcings are applied together with business-as-usual IPCC-A2 carbon emissions scenario. We show that very large volcanic eruptions similar to Tambora lead to short-term substantial global cooling. However, over a long period, smaller but more frequent eruptions, such as Pinatubo, would hav...

  16. Volatile Transport by Volcanic Plumes on Earth, Venus and Mars

    Science.gov (United States)

    Glaze, Lori S.; Self, Stephen; Baloga, Steve; Stofan, Ellen R.

    2012-01-01

    Explosive volcanic eruptions can produce sustained, buoyant columns of ash and gas in the atmosphere (Fig. 1). Large flood basalt eruptions may also include significant explosive phases that generate eruption columns. Such eruptions can transport volcanic volatiles to great heights in the atmosphere. Volcanic eruption columns can also redistribute chemical species within the atmosphere by entraining ambient atmosphere at low altitudes and releasing those species at much higher altitudes.

  17. Los volcanes del Sistema Volcánico Transversal

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    Esperanza Yarza de la Torre

    2012-02-01

    Full Text Available Si hizo la selección de textos referentes a algunos de los volcanes que integran el Sistema Volcánico Transversal. Publicado en: Yarza de De la Torre, E. (1992, "Los volcanes del Sistema Volcánico Transversal", Volcanes de México, 4a ed. corregida y aumentada, Instituto de Geografía, UNAM, México, pp. 82-83, 89-136.

  18. Los volcanes del Sistema Volcánico Transversal

    OpenAIRE

    Esperanza Yarza de la Torre

    2003-01-01

    Si hizo la selección de textos referentes a algunos de los volcanes que integran el Sistema Volcánico Transversal. Publicado en: Yarza de De la Torre, E. (1992), "Los volcanes del Sistema Volcánico Transversal", Volcanes de México, 4a ed. corregida y aumentada, Instituto de Geografía, UNAM, México, pp. 82-83, 89-136.

  19. 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

  20. Why Are Nigeria-Cameroon Chimpanzees (Pan troglodytes ellioti) Free of SIVcpz Infection?

    Science.gov (United States)

    Locatelli, Sabrina; Harrigan, Ryan J; Sesink Clee, Paul R; Mitchell, Matthew W; McKean, Kurt A; Smith, Thomas B; Gonder, Mary Katherine

    2016-01-01

    Simian immunodeficiency virus (SIV) naturally infects two subspecies of chimpanzee: Pan troglodytes troglodytes from Central Africa (SIVcpzPtt) and P. t. schweinfurtii from East Africa (SIVcpzPts), but is absent in P. t. verus from West Africa and appears to be absent in P. t. ellioti inhabiting Nigeria and western Cameroon. One explanation for this pattern is that P. t. troglodytes and P. t schweinfurthii may have acquired SIVcpz after their divergence from P. t. verus and P. t. ellioti. However, all of the subspecies, except P. t. verus, still occasionally exchange migrants making the absence of SIVcpz in P. t. ellioti puzzling. Sampling of P. t. ellioti has been minimal to date, particularly along the banks of the Sanaga River, where its range abuts that of P. t. troglodytes. This study had three objectives. First, we extended the sampling of SIVcpz across the range of chimpanzees north of the Sanaga River to address whether under-sampling might account for the absence of evidence for SIVcpz infection in P. t. ellioti. Second, we investigated how environmental variation is associated with the spread and prevalence of SIVcpz in the two chimpanzee subspecies inhabiting Cameroon since environmental variation has been shown to contribute to their divergence from one another. Finally, we compared the prevalence and distribution of SIVcpz with that of Simian Foamy Virus (SFV) to examine the role of ecology and behavior in shaping the distribution of diseases in wild host populations. The dataset includes previously published results on SIVcpz infection and SFVcpz as well as newly collected data, and represents over 1000 chimpanzee fecal samples from 41 locations across Cameroon. Results revealed that none of the 181 P. t. ellioti fecal samples collected across the range of P. t. ellioti tested positive for SIVcpz. In addition, species distribution models suggest that environmental variation contributes to differences in the distribution and prevalence of SIVcpz and

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

    Science.gov (United States)

    Munung, Nchangwi Syntia; Tangwa, Godfrey B; Che, Chi Primus; Vidal, Laurent; Ouwe-Missi-Oukem-Boyer, Odile

    2012-06-11

    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. 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. 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. 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 equipped with thorough knowledge and practice of

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

    Directory of Open Access Journals (Sweden)

    Munung Nchangwi

    2012-06-01

    Full Text Available Abstract 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

  3. Adolescent deliveries in rural Cameroon: an 8-year trend, prevalence and adverse maternofoetal outcomes.

    Science.gov (United States)

    Agbor, Valirie Ndip; Mbanga, Clarence Mvalo; Njim, Tsi

    2017-09-29

    Adolescent deliveries remain a global public health concern especially in low- and middle-income countries where 95% of these deliveries occur. In Cameroon, adolescent pregnancies have a high disease burden due to their association with adverse pregnancy outcomes. We sought to evaluate the prevalence, trend and adverse maternofoetal outcomes of adolescent deliveries in a rural community in Cameroon. We carried out a retrospective register analysis of 1803 singleton deliveries in two health facilities located in the Oku sub-division over an 8-year period (2009 to 2016). We excluded: records without maternal age, babies born before arrival, birthweights less than 1000 g, multiple deliveries and deliveries before 28 weeks gestation. Data analysis was done using Epi info 7.0.8.3. The Fisher's exact test was used to compare categorical variables, while the chi-square test for trends was used to determine time trends. P-values below 5% were considered statistically significant. The 8-year prevalence of adolescent deliveries was 20.4% (95% CI = 18.6-22.4) with a significant, downward trend between 2009 and 2016 (P trend = 0.05). Second-fourth degree perineal tears were more likely to complicate adolescent (Age trend in the prevalence of adolescent deliveries was associated with a significant decrease in the trend of neonatal asphyxia at the fifth minute. Married adolescents and their babies were as likely to develop the complications of adolescent delivery such as second-fourth degree perineal tears (OR = 0.8; 95% CI = 0.4-1.6; p = 0.456), low birthweight (OR = 2.1; 95% CI = 0.9-4.7; p = 0.070) and fifth minute neonatal asphyxia (OR = 0.9; 95% CI = 0.4-2.0; p = 0.832) as single adolescents and their babies. The prevalence of adolescent deliveries in this rural community is high with one of every five babies born to an adolescent mother. Despite the downward trend indicating a decrease in adolescent deliveries, our study demonstrates the need to

  4. The spectrum of skin diseases in a rural setting in Cameroon (sub-Saharan Africa

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    Bissek Anne-Cécile

    2012-06-01

    Full Text Available Abstract Background Skin disorders are generally considered to be more prevalent in the rural areas of Cameroon. This study was carried out to verify this assumption by describing the spectrum of skin disorders in a rural setting of Cameroon. Methods We carried out a community-based clinical skin examination of 400 consenting subjects from 4 villages of Cameroon: Nyamanga (27%, Yebekolo (24%, Mbangassina (23% and Bilomo (26%. Results The overall prevalence of skin diseases in our sample was 62% {95% CI: 57.2%, 66.8%} (248/400. The commonest skin disorders were: fungal infections (25.4%, parasitic infestations (21.4%, atrophic skin disorders (11.7%, hypertrophic skin disorders (9.7%, disorders of skin appendages {acne} (8.9%, benign neoplasm (6.5%, bacterial skin infections (5.2%, pigmentation disorders (4.8%, and dermatitis/eczema (4.0%. Skin infections and infestations constituted 52.82% of all skin disorders. The overall prevalence of infectious and parasitic infestation was 32.75% {95%CI: 28.17%, 37.59%} (131/400 as against 29.25% {95%CI: 24.83%, 33.98%} (117/400 for non-infectious disorders. Among people with skin infections/parasitic infestations, those with fungal infections and onchocercal skin lesions were the most prevalent, accounting for 48.1% (63/131 and 35.1% (46/131; and an overall prevalence of 15.75% {95%CI: 12.3%, 19.7%} (63/400 and 11.5% {95%CI: 8.5%, 15.0%} (46/400 respectively. There was secondary bacterial infection in 12.1% {95%CI: 8.31%, 16.82%} (30/248 of subjects with skin diseases. Hypertrophic and atrophic disorders of the skin were mainly keloids (9.68%, scarification marks (6.05% and burn scars (5.65%. Skin diseases like dermatitis and eczema (4.03%, malignant tumours and pigmentation disorders were rare in our sample. The proportion of subjects diagnosed with skin disorders after examination (62.8% was significantly higher than the proportion of 40.8% that declared having skin diseases (p  Conclusion The

  5. Prevalence and factors associated with depression among medical students in Cameroon: a cross-sectional study.

    Science.gov (United States)

    Ngasa, Stewart Ndutard; Sama, Carlson-Babila; Dzekem, Bonaventure Suiru; Nforchu, Kilton Neba; Tindong, Maxime; Aroke, Desmond; Dimala, Christian Akem

    2017-06-09

    Depression is an important contributor to the global burden disease that affects people of communities all over the world. With high level of demands in academics and psychosocial pressure, medical students during their course of training tend to become depressed, leading to problems later in professional life and compromising patient care. In Cameroon, there is lack of data on the prevalence of depression and its impact on medical students. To determine the prevalence and predisposing factors associated with depression among medical students in Cameroon (preclinical and clinical). We also evaluated the impact of depression on self-reported academic performance. A cross sectional study was carried out in all 4 state medical schools in 4 different regions from December 2015 to January 2016. Diagnosis of depression, major depression and its associated factors were assessed using the 9-Item-Patient Health Questionnaire (PHQ-9) and a structured questionnaire respectively. We included 618 medical students (response rate: 90.4%). About a third of them (30.6%, 95% CI: 22.8-36.7) were found to have major depressive disorder (PHQ Score ≥ 10). With regards to the severity of depression, 214 (34.6%), 163 (26.4%), 21 (3.4%), and 5 (0.80%) students were classified as having mild, moderate, moderately severe and severe depression respectively. The presence of a chronic disease (OR: 3.70, 95% CI: 1.72-7.94, p = 0.001), major life events (OR: 2.17, 95%CI: 1.32-3.58, P = 0.002), female gender (OR: 1.59, 95% CI: 1.06-2.37, p = 0.024) and being a student at the clinical level (OR: 4.26, 95% CI: 2.71-6.71, p depression. There was no association between depression and self-reported academic performance, (OR: 1.2, 95% CI: 0.9-1.7, p = 0.080). The prevalence of major depressive disorders among medical students in Cameroon is high and is associated with the presence chronic disease, major life events, female gender and being a student at the clinical level. So we recommend

  6. Map of biomedical research in Cameroon; a documentary review of approved protocols from 1997 to 2012.

    Science.gov (United States)

    Walter, Ebile Akoh; Jerome, Ateudjieu; Marceline, Djuidje Ngounoue; Yakum, Martin Ndinakie; Pierre, Watcho

    2017-11-21

    Over the last decade, there has been a rapid increase in biomedical research in Cameroon. However, the question of whether these research projects target major health priorities, vulnerable populations and geographic locations at risk remains to be answered. The aim of this paper is to describe the state of biomedical research in Cameroon which is a key determinant that would guide future health care policies and promote equitable access to healthcare. A documentary review of all approved protocols (proposals) of biomedical research projects, from 1997 through 2012, at the Cameroon National Ethics Committee. Protocols were reviewed systematically by independent reviewers and data were extracted on a grid. Data were analyzed by calculating proportions at 95% confidence interval, chi-square test (chi2) and p-values. Two thousand one hundred seventy two protocols were reviewed for data extraction. One thousand three hundred ninety-five (64.7%) were student projects, 369 (17.0%) projects had international sponsors, and 1528 (72.4%) were hospital-based studies. The most targeted domain was the fight against diseases 1323 (61.3%); mostly HIV 342 (25.8%) and Malaria 136 (10.3%). Over half of the studies were concentrated in the Centre region 1242 (57.2%), with the least projects conducted in the Northern region 15 (0.7%). There was strong evidence that international and local sponsors would influence the research site (p-value = 0.01) and population targets (p-value = 0.00). Although biomedical research targets some important diseases that pose a great burden to Cameroonians, the most vulnerable populations are excluded from research. Biomedical research scarcely addresses other components of the health system and emerging diseases of vital public health importance. We recommend that the government should play a central role, between researchers from academic institutions, sponsors, NGOs and research institutions, to ensure that biomedical research addresses the

  7. Application of NIR Laser Spectroscopy to the Monitoring of Volcanic Plumes: Principles and Practicalities

    Science.gov (United States)

    Hamish, A.; Christenson, B. W.; Mazot, A.

    2014-12-01

    The major volatile species in volcanic plume emissions (i.e., H2O, CO2, SO2, HCl, HF) are all strongly infrared (IR)-active, and lend themselves to infrared spectroscopic analysis. However, physical/optical access to plume gases along pathways which include a suitable natural or active IR radiation source is often difficult or impossible to achieve, particularly for timeframes extending beyond short campaign periods. In this study, we present results from preliminary tests conducted on three volcanic CO2 plume emissions using a tunable diode NIR laser system (TDL, Boreal Laser Inc.). The approach is proving itself as a good candidate for continuous monitoring of volcanic plume CO2, and by default all other IR-active constituents for which lasers of appropriate wavelength are available. The CO2 system is configured with a TDL in a transceiver generating laser light which can be tuned to coincide with one of several absorption lines in the CO2 absorption band between 1575 nm and 1585 nm. This beam propagates through the atmosphere (and plume) to a retro-reflector, which returns the beam to a photodiode detector in the transceiver which processes the signal to report real time CO2 column densities. The CO2 absorption line at 1579.1 nm was used to good effect on Mt Ruapehu (NZ) where volcanic gases emanate through a 100 m deep crater lake, resulting in CO2 concentrations of > 78 ppm above background in the mixing zone varying from 4 to 30 m above the lake surface. Subsequent tests on the main plume at White Island, however, generated only poor results with indicated CO2 amounts being less than atmospheric. We concluded that this was the result of interference from a neighboring but comparatively minor H2O absorption band which in the proximal, higher temperature plume (estimated 50-70 °C), had H2O concentrations some 4-5 times greater than ambient. A change to a less sensitive absorption line further removed from potential H2O band interference (1567.9 nm) appears to

  8. 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

  9. The Martian highland paterae: Evidence for explosive volcanism on Mars

    Science.gov (United States)

    Crown, David A.; Greeley, Ronald

    1988-01-01

    The Martian surface exhibits numerous volcanic landforms displaying great diversity in size, age, and morphology. Most research regarding Martian volcanology has centered around effusive basaltic volcanism, including analyses of individual lava flows, extensive lava plains, and large shield volcanoes. These studies were hindered by a lack of definitive morphologic criteria for the remote identification of ash deposits. Knowledge of the abundances, ages, and geologic settings of explosive volcanic deposits on Mars is essential to a comprehensive understanding of the evolution of the Martian surface, with implications for the evolution of the lithosphere and atmosphere as well as the histories of specific volcanic centers and provinces.

  10. Effect of volcanic tuff on the characteristics of cement mortar

    Directory of Open Access Journals (Sweden)

    Jehad Al-Zou'by

    2014-06-01

    Full Text Available This paper examines how Jordanian volcanic tuff aggregates affect the characteristics of cement mortar. Five mortar mixes were prepared by replacing normal aggregate (standard sand with volcanic tuff aggregate in ratios of 0, 25, 50, 75, and 100% (M1 to M5, respectively. Compressive strength, flexural strength, and unit weight were tested at mortar ages of 3, 7, 28, and 56 days. The results revealed improved compressive and flexural strength, which were maximal for the M3 sample. Unit weight decreased as the ratio of volcanic tuff increased. Based on these results, adding Jordanian volcanic tuff in the appropriate ratio will improve these mortar characteristics.

  11. High Line

    DEFF Research Database (Denmark)

    Kiib, Hans

    2015-01-01

    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......, and galleries. With the High Line, a new urban architectural typology has been created that is aesthetically enriching and sets new standards for urban transformation and urban life. “The park accommodates the wild, the cultivated, the intimate and the social. Access points are durational experiences designed...

  12. The volcanic and tectonic history of Enceladus

    Science.gov (United States)

    Kargel, J.S.; Pozio, S.

    1996-01-01

    Enceladus has a protracted history of impact cratering, cryo-volcanism, and extensional, compressional, and probable strike-slip faulting. It is unique in having some of the outer Solar System's least and most heavily cratered surfaces. Enceladus' cratering record, tectonic features, and relief elements have been analyzed more comprehensively than done previously. Like few other icy satellites, Enceladus seems to have experienced major lateral lithospheric motions; it may be the only icy satellite with global features indicating probable lithospheric convergence and folding. Ridged plains, 500 km across, consist of a central labyrinthine ridge complex atop a broad dome surrounded by smooth plains and peripheral sinuous ridge belts. The ridged plains have few if any signs of extension, almost no craters, and an average age of just 107 to 108 years. Ridge belts have local relief ranging from 500 to 2000 m and tend to occur near the bottoms of broad regional troughs between swells. Our reanalysis of Peter Thomas' (Dermott, S. F., and P. C. Thomas, 1994, The determination of the mass and mean density of Enceladus from its observed shape, Icarus, 109, 241-257) limb profiles indicates that high peaks, probably ridge belts, also occur in unmapped areas. Sinuous ridges appear foldlike and are similar to terrestrial fold belts such as the Appalachians. If they are indeed folds, it may require that the ridged plains are mechanically (perhaps volcanically) layered. Regional topography suggests that folding may have occurred along zones of convective downwelling. The cratered plains, in contrast to the ridged plains, are heavily cratered and exhibit extensional structures but no obvious signs of compression. Cratered plains contain a possible strike-slip fault (Isbanir Fossa), along which two pairs of fractures seem to have 15 km of right-lateral offset. The oldest cratered plains might date from shortly after the formation of the saturnian system or the impact disruption and

  13. 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.

  14. 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.

  15. Hubble Captures Volcanic Eruption Plume From Io

    Science.gov (United States)

    1997-01-01

    The Hubble Space Telescope has snapped a picture of a 400-km-high (250-mile-high) plume of gas and dust from a volcanic eruption on Io, Jupiter's large innermost moon.Io was passing in front of Jupiter when this image was taken by the Wide Field and Planetary Camera 2 in July 1996. The plume appears as an orange patch just off the edge of Io in the eight o'clock position, against the blue background of Jupiter's clouds. Io's volcanic eruptions blasts material hundreds of kilometers into space in giant plumes of gas and dust. In this image, material must have been blown out of the volcano at more than 2,000 mph to form a plume of this size, which is the largest yet seen on Io.Until now, these plumes have only been seen by spacecraft near Jupiter, and their detection from the Earth-orbiting Hubble Space Telescope opens up new opportunities for long-term studies of these remarkable phenomena.The plume seen here is from Pele, one of Io's most powerful volcanos. Pele's eruptions have been seen before. In March 1979, the Voyager 1 spacecraft recorded a 300-km-high eruption cloud from Pele. But the volcano was inactive when the Voyager 2 spacecraft flew by Jupiter in July 1979. This Hubble observation is the first glimpse of a Pele eruption plume since the Voyager expeditions.Io's volcanic plumes are much taller than those produced by terrestrial volcanos because of a combination of factors. The moon's thin atmosphere offers no resistance to the expanding volcanic gases; its weak gravity (one-sixth that of Earth) allows material to climb higher before falling; and its biggest volcanos are more powerful than most of Earth's volcanos.This image is a contrast-enhanced composite of an ultraviolet image (2600 Angstrom wavelength), shown in blue, and a violet image (4100 Angstrom wavelength), shown in orange. The orange color probably occurs because of the absorption and/or scattering of ultraviolet light in the plume. This light from Jupiter passes through the plume and is

  16. 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.

  17. Automatic classification of seismo-volcanic signatures

    Science.gov (United States)

    Malfante, Marielle; Dalla Mura, Mauro; Mars, Jérôme; Macedo, Orlando; Inza, Adolfo; Métaxian, Jean-Philippe

    2017-04-01

    The prediction of volcanic eruptions and the evaluation of their associated risks is still a timely and open issue. For this purpose, several types of signals are recorded in the proximity of volcanoes and then analysed by experts. Typically, seismic signals that are considered as precursor or indicator of an active volcanic phase are detected and manually classified. In this work, we propose an architecture for automatic classification of seismo-volcanic waves. The system we propose is based on supervised machine learning. Specifically, a prediction model is built from a large dataset of labelled examples by the means of a learning algorithm (Support Vector Machine or Random Forest). Four main steps are involved: (i) preprocess the signals, (ii) from each signal, extract features that are useful for the classes discrimination, (iii) use an automatic learning algorithm to train a prediction model and (iv) classify (i.e., assign a semantic label) newly recorded and unlabelled examples. Our main contribution lies in the definition of the feature space used to represent the signals (i.e., in the choice of the features to extract from the data). Feature vectors describe the data in a space of lower dimension with respect to the original one. Ideally, signals are separable in the feature space depending on their classes. For this work, we consider a large set of features (79) gathered from an extensive state of the art in both acoustic and seismic fields. An analysis of this feature set shows that for the application of interest, 11 features are sufficient to discriminate the data. The architecture is tested on 4725 seismic events recorded between June 2006 and September 2011 at Ubinas, the most active volcano of Peru. Six main classes of signals are considered: volcanic tremors (TR), long period (LP), volcano-tectonic (VT), explosion (EXP), hybrids (HIB) and tornillo (TOR). Our model reaches above 90% of accuracy, thereby validating the proposed architecture and the

  18. Venus - False Color of Volcanic Plains

    Science.gov (United States)

    1992-01-01

    This Magellan full-resolution mosaic of Venus, centered at 10 degrees north latitude, 301 degrees east longitude, shows an area replete with diverse volcanic features. The image, of an area 489 kilometers long by 311 kilometers wide (303 by 193 miles), is dominated by volcanic plains which appear mottled because of varying roughnesses of each solidified lava flow. The rougher the terrain the brighter it appears in the radar image. The small, bright bumps clustered in the left portion of the image are a grouping of small volcanoes called a shield field. Each shield volcano is approximately 2 to 5 kilometers (1.2 to 3.1 miles) in diameter and has very subdued relief. It is believed that the lava flows that make up each shield originates from a common source. To the right of the shield field is another type of volcano, called a scalloped dome. It is 25 kilometers (16 miles) in diameter and has a central pit. Some of the indistinct lobe-shaped pattern around the dome may either be lava flows or rocky debris which has fallen from the scalloped cliffs surrounding the domes. The small radial ridges characteristic of scalloped domes are remnants of catastrophic landslides. To the right of that feature is a large depression called a volcanic caldera. The caldera was formed when lava was expelled from an underground chamber, which when emptied, subsequently collapsed forming the depression. The feature furthermost to the east (right) is another scalloped dome, 35 kilometers (22 miles) in diameter. That feature is unusual in that lava came out through the southeastern margin, rafting a large portion of the dome for 20 kilometers (12 miles). The lava continues into the lower right portion of the area in the image. Its steep rounded boundaries suggest it was a very sticky, oozing lava. That same type of lava is what scientists propose formed the steep-sided domes such as the bright, round feature, slightly northeast of center. It is highly likely that the features are all part

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

    Directory of Open Access Journals (Sweden)

    Islay Mactaggart

    Full Text Available To investigate the relationship between two distinct measures of disability: self-reported functional limitations and objectively-screened clinical impairments.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.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 participation restrictions

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

    Science.gov (United States)

    Mactaggart, Islay; Kuper, Hannah; Murthy, G V S; Oye, Joseph; Polack, Sarah

    2016-01-01

    To investigate the relationship between two distinct measures of disability: self-reported functional limitations and objectively-screened clinical impairments. 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. 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 participation restrictions. Tools to