The Cameroon line, West Africa, and its bearing on the origin of oceanic and continental alkali basalt

International Nuclear Information System (INIS)

Fitton, J.G.

1985-01-01

The Cameroon line is a unique within-plate volcanic province which straddles a continental margin. It 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. It provides, therefore, an ideal area in which to compare the sub-oceanic and sub-continental mantle sources for alkali basalt. Basaltic rocks in the oceanic and continental sectors are geochemically and isotopically indistinguishable which suggests that they have identical mantle sources. This conclusion rules out substantial lithosphere involvement in the generation of alkali basalts and therefore weakens the case for mantle metasomatism as a necessary precursor to alkaline magmatism. The convecting upper mantle is a much more likely source as it will be well-stirred and unlikely to show any ocean-continent differences. The long history of Cameroon line magmatism (65 Ma) and lack of evidence for migration of volcanism with time makes a deeper mantle source unlikely. Mid-ocean ridge basalts (MORB) also originate within the convecting upper mantle and so must share a common source with the Cameroon line alkali basalts (and, by implication, ocean island and continental rift basalts). A grossly homogeneous mantle with a bulk composition depleted in large-ion lithophile elements (LILE), but containing streaks of old, LILE-enriched material, provides a plausible common source. Large degree, near-surface melting of such a source would produce MORB. Smaller degree melts produced at deeper levels would percolate upwards along grain boundaries and become enriched in LILE by leaching LILE-rich grain boundary films. The mixing of these liquids with melts from the LILE-rich streaks will produce magmas with the geochemical and isotopic features of ocean island basalts. (orig.)

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

International Nuclear Information System (INIS)

Tokam, Alain-Pierre K.; Tabod, Charles T.; Nyblade, Andrew A.; Jordi Julia; Wiens, Douglas A.; Pasyanos, Michael E.

2009-09-01

The joint inversion of Rayleigh wave group velocities and receiver functions was carried out to investigate the crustal and uppermost mantle structures beneath Cameroon. This was achieved using data from 32 broadband seismic stations installed for 2 years across Cameroon. The Moho depth estimates reveal that the Precambrian crust is variable across the country and shows some significant differences compared to other similar geologic units in East and South Africa. These differences suggest that the setting of the Cameroon Volcanic Line (CVL) and the eastward extension of the Benue Trough have modified the crust of the Panafrican mobile belt in Cameroon by thinning beneath the Rift area and CVL. The velocity models obtained from the joint inversion show at most stations, a layer with shear wave velocities ≥ 4.0 km/s, indicating the presence of a mafic component in the lower crust, predominant beneath the Congo Craton. The lack of this layer at stations within the Panafrican mobile belt may partly explain the crustal thinning observed beneath the CVL and rift area. The significant presence of this layer beneath the Craton, results from the 2100 Ma magmatic events at the origin of the emplacement of swarms of mafic dykes in the region. The CVL stations are underlain by a crust of 35 km on average except near Mt-Cameroon where it is about 25 km. The crustal thinning observed beneath Mt. Cameroon supported by the observed positive gravity anomalies here, suggests the presence of dense astenospheric material within the lithosphere. Shear wave velocities are found to be slower in the crust and uppermost mantle beneath the CVL than the nearby tectonic terrains, suggesting that the origin of the line may be an entirely mantle process through the edge-flow convection process. (author)

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, ...

An endangered species in Cameroon

African Journals Online (AJOL)

Justine Nzweundji

2015-08-19

Aug 19, 2015 ... 2002) and one of the main sources of supply to satisfy this demand consists of Cameroon natural populations. (Nsawir and Ingram, 2007). Unfortunately, much of this exploitation has been ..... Prunus africana: Money growing on trees? A plant that can boost rural economies in the Cameroon Highlands.

Cameroon.

Science.gov (United States)

1992-06-01

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

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.

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

African Journals Online (AJOL)

... for the rapid exploitation of biotechnology for the socioeconomic development of Cameroon, subject to the mobilization of the necessary venture capital. Keywords: Cameroon, Biotechnology, GMO, Biodiversity, Economic Development, Recombinant DNA JOURNAL OF THE CAMEROON ACADEMY OF SCIENCES Vol.

Opposition Politics and Electoral Democracy in Cameroon, 1992-2007

African Journals Online (AJOL)

2015-05-29

May 29, 2015 ... This article seeks to assess the impact of electoral democracy in. Cameroon especially ... Democratic Party (KNDP), the Cameroon People National Congress (CPNC) and the Cameroon .... The Supreme Court cancelled the election results in seven constituencies ..... Church and the media (Ake 2000:135).

Cenozoic intra-plate magmatism in the Darfur volcanic province: mantle source, phonolite-trachyte genesis and relation to other volcanic provinces in NE Africa

Science.gov (United States)

Lucassen, Friedrich; Pudlo, Dieter; Franz, Gerhard; Romer, Rolf L.; Dulski, Peter

2013-01-01

Chemical and Sr, Nd and Pb isotopic compositions of Late Cenozoic to Quaternary small-volume phonolite, trachyte and related mafic rocks from the Darfur volcanic province/NW-Sudan have been investigated. Isotope signatures indicate variable but minor crustal contributions. Some phonolitic and trachytic rocks show the same isotopic composition as their primitive mantle-derived parents, and no crustal contributions are visible in the trace element patterns of these samples. The magmatic evolution of the evolved rocks is dominated by crystal fractionation. The Si-undersaturated strongly alkaline phonolite and the Si-saturated mildly alkaline trachyte can be modelled by fractionation of basanite and basalt, respectively. The suite of basanite-basalt-phonolite-trachyte with characteristic isotope signatures from the Darfur volcanic province fits the compositional features of other Cenozoic intra-plate magmatism scattered in North and Central Africa (e.g., Tibesti, Maghreb, Cameroon line), which evolved on a lithosphere that was reworked or formed during the Neoproterozoic.

Marketing of Accommodation services : Case-Hotel Azam Cameroon

OpenAIRE

Youkam, Germaine

2012-01-01

Cameroon is Africa in miniature with a lot of tourist attractions owing to its geological and cultural diversity. Natural features include beaches, deserts, mountains, rainforests, and savannas. Accommodation services have been a grand phenomenon within the tourism industry in Cameroon. The accommodation sector has developed tremendously within the past decades. The objective of this research work was to find about out the marketing of accommodation services in Cameroon with Hotel Azam as...

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.

Environmental exposure to carcinogens in northwestern Cameroon

African Journals Online (AJOL)

EB

2013-09-03

Sep 3, 2013 ... 3. Department of Biomedical Sciences, Faculty of Health Sciences, University of Buea, Cameroon. 4. Department of Medical Laboratory Sciences, ... the leading causes of death. Lung cancer has been reported from Cameroon17 but no association has been established between cigarette smoking and lung ...

Implications of the Bakassi conflict resolution for Cameroon

African Journals Online (AJOL)

the security and economic interests of the colonial powers. After independence, ... nation-state intervenes in the domestic disputes of another state. Occasionally, a .... and in Cameroon, where the Southern Cameroon National Council (SCNC).

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.

Approaches to mastering the uranium potential of Cameroon

International Nuclear Information System (INIS)

Chakam Tagheu, P.; Simo, A.

2014-01-01

Uranium deposits are spread over the five continents. According to the International Atomic Energy Agency (IAEA) estimation in 2009, the global reserves of economically recoverable uranium are estimated at 4.5 million tonnes. In 2012, the world production of uranium was about 54,610 tonnes and the main producers were Kazakhstan (36%), Canada (15%) and Australia (12%). Brazil, Russia, China, India productions accounted for 9.4% of the overall world production. Significant deposits also exist in Africa including Cameroon; those currently in mining stage are in Namibia, Malawi, and Niger. Cameroon has significant mineral deposits such as gold, alluvial diamonds, iron, bauxite and uranium. All of them are still in the exploration stage. Although Cameroon has not launched a nuclear power programme, the mining of its uranium resources is considered as an important component of the national economy. Many uranium occurrences have so far been discovered in Cameroon. They include Kitongo, Salaki, Mayo Nielse and Teubang in the Northern region and Ngombas near Lolodorf in the Southern region. The Cameroon Government is engaged in (i) the assessment of the U-ore resource through drilling, and (ii) the airborne geophysical survey of mining potentials areas. The result of these studies may lead to a better estimation of the national uranium potential. This paper aims at pointing out constraints to assess the uranium potential of Cameroon and proposes measures that could improve on the leveraging of exploitation of this mineral. (author)

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

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

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 ...

Solar energy in the Northern Cameroon

International Nuclear Information System (INIS)

Djuikom, M.; Ndjomaha, Ch.; Vandenbergh, M.

2004-01-01

In 2003, the Cameroon Ministry of the Environment and Forestry has initiated a research project for studying the promotion of renewable energies and their impact on rural development. This work has been realized jointly with the department of Economy and Rural Development of the Agronomic University of Gembloux (Belgium), the Centre Des Etudes de L'Environnement et de Developpement du Cameroun (CEDC, Maroua) and the Institut fur Solare Energieversorgungstechnik (ISET, Germany). This initiative comes when the electricity sector in Cameroon has been facing important changes (Privatization of the national company of electricity, creation of a rural electrification agency, multiplication of the dialogues and seminars around the strategies of promotion for renewable energies, frequent black-outs during the dry season). The first objective of the project is to contribute to a better knowledge of the situation of the use of renewable energies in Cameroon. Therefore, Mrs Marthe Djuikom undertook from July to September 2003 a socio-economic survey on the use of solar energy in the northern Cameroon. The next step will be the creation of an energy program at the CEDC with the following tasks: promotion of photovoltaic technology, support of local and international synergies on the organisational aspects, training, information and coordination of reflexions at the local level for the promotion of rural electrification projects. (authors)

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, ...

Canine and Human Rabies in Cameroon | Awah | Tropical ...

African Journals Online (AJOL)

This paper is a retrospective review of recorded rabies and antirabies activities in Cameroon from 1990 to 1999 to determine the current state of rabies in both dogs and humans. Rabies and antirabies activities were recorded every year in Cameroon through out the 10-year study period with the highest values observed in ...

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.

Country programme review Republic of Cameroon

International Nuclear Information System (INIS)

Cherif, H.C.; Hasling, W.; Hera, C.H.; Maudarbocus, A.Y.; Mtimet, S.

1993-10-01

A multi-disciplinary country programme review and programming mission was undertaken to the Republic of Cameroon, from 21 to 25 June 1993. This report reflects the findings and recommendations of the mission and falls into four sections. The first section describes the country profile and includes information about its economy and its development plans and policies. The second reviews the Agency's past and present technical co-operation programmes in Cameroon. The third section deals with a sectoral programme and institutional review, and the fourth section presents possible future technical co-operation activities

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

African Journals Online (AJOL)

Introduction: 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. Methods: We conducted a systematic review, bibliometric ...

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

African Journals Online (AJOL)

Linguistic inequality in Cameroon: The case of advertising in Douala. ... multilingualism and multiculturalism in Cameroon, very little has been done in advertising as it reflects language representation. Much of ... AJOL African Journals Online.

International Uranium Resources Evaluation Project (IUREP) orientation phase mission report: Cameroon. Draft

International Nuclear Information System (INIS)

Trey, Michel de; Leney, George W.

1983-05-01

Geology Branch with mapping and exploration services. Most of CAMEROON is underlain by Precambrian granites , anatexites, migmatites, gneisses, and schists. The NTEM complex in the south is Archean age. Most other areas are probably Lower Proterozoic, with some Middle Proterozoic inliers of the LOM, POLI, and MBALMAYO-BENGBIS, and the DJA series in the southeast. The DJA tillite is probably Upper Proterozoic. There are small remnant basins of Paleozoic volcanics, and larger basins and grabens of Middle-Upper Cretaceous. Tertiary rocks are present in the Coastal basins and the southeast. The Lake Chad depression is covered with Quaternary sands. All of the older rocks except the NTEM complex and the DJA series are within the Panafrican Mobile Belt. The border faults of the Cretaceous BENOUE graben are throughgoing crustal features. Tertiary intrusives and plateau basalts are found along the 'LINE OF CAMEROON', and volcanism has continued to present. Uranium exploration from 1950 to present has produced mostly negative results. Only one important prospect has been found at GOBLE-KITONGO, and has been the subject of repeated exploration from 195 8 to present. An enriched zone in syenite at LOLODORF is also under investigation. Anomalies on an airborne survey of the DJA series are being checked for mineralization similar to the FRANCEVILLIAN of GABON. Total expenditures that may be assigned to uranium are on the order of $10 million (U.S.). There are no uranium ore reserves or reasonably assured resources in CAMEROON. Speculative resources of 10,000 tonnes have been assigned to the LOLODORT syenite, and 5000 tonnes to the GOBLE-KITONGO prospect and Paleozoic volcanics at $130/kg. (U.S.). Favorable areas are the DJA series, syenites of the Panafrican granite and 'granites ultimes', Mesozoic-Cenozoic basins (especially DOUALA), LOM and MBALMAYO-BENGBIS series, POLI-MAROUA, and Lower Proterozoic/Archean gneiss and granite. Recommendations have been made for topical studies of

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.

Aedes (Stegomyia) albopictus (Skuse), a potential new Dengue vector in southern Cameroon.

OpenAIRE

Fontenille, D.; Toto, J. C.

2001-01-01

Aedes albopictus, a mosquito vector of Dengue virus, has been recorded for the first time in Cameroon. Entomologic surveys in 2000 demonstrated that it is widespread in southern Cameroon, colonizing a wide variety of breeding sites and biting humans in every district surveyed. The presence of this vector increases the risk for emergence of dengue in Cameroon.

Dentofacial injuries in contact sports in Yaounde, Cameroon

OpenAIRE

M A Agbor; C C Azodo; N. E. F. Ngagoue

2012-01-01

Background: Dentofacial injuries constitute serious problems among competitive and recreational athletes, worldwide. Objective: To determine the prevalence of dentofacial injuries and related factors among individuals participating in contact sports in Yaoundé, Cameroon. Materials and Methods: This cross-sectional study among individuals participating in karate, judo, basketball, handball, football and wrestling in Yaoundé, Cameroon was conducted between January and April, 2012. Results: Of t...

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 ...

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 ...

The contractual and legal framework for petroleum exploration in Cameroon

International Nuclear Information System (INIS)

Ndi, George

1992-01-01

Cameroon has been a producer and net exporter of oil now for almost 15 years, although the country remains a minor player in the international oil industry. However, with its privileged location on the West African coast and an offshore oil industry which is centred on the Gulf of Guinea, Cameroon has been, and remains, a regional oil producer of some importance. This article sets out to analyse the legal aspects of the commercial exploitation of oil in Cameroon by examining the applicable law, exploration/production contracts, and the fiscal regime. Its purpose is to try to provide a setting which facilitates a proper understanding of the legal frame-work in which the petroleum industry operates in Cameroon, as well as an indication of the direction of government policy towards the further development and expansion of the industry. But first, it will be useful to begin the discussion with an examination of the role of petroleum production in the national economy. (author)

CTBTO international monitoring system: Status of work in Cameroon and perspectives

International Nuclear Information System (INIS)

Nyobe, J.B.

2002-01-01

The presentation outlines Cameroon's participation in CTBTO programme and its seismic activities. Areas of inter-regional and international cooperation are described. Suggestions are made on ways in which Cameroon can contribute to the work of the commission

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 ...

Journal of the Cameroon Academy of Sciences: About this journal

African Journals Online (AJOL)

Journal of the Cameroon Academy of Sciences: About this journal. Journal Home > Journal of the Cameroon Academy of Sciences: About this journal. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register · Journal Home · ABOUT THIS JOURNAL · Advanced Search ...

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 ...

Adaptation of Regional Representative Soil Project and Soil Judging for Cameroon

Science.gov (United States)

Che, Celestine Akuma

2013-01-01

Representative regional soils have agricultural, cultural, economic, environmental, and historical importance to Cameroon. Twenty seven regional representative soils have been identified in Cameroon. A set of laboratory exercises, assignments and exam questions have been developed utilizing the Regional Representative Soil Project (RRSP) that…

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

NARCIS (Netherlands)

Jua, N.

1990-01-01

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

The Anglophone Cameroon-Nigeria boundary: Opportunities and conflicts

International Nuclear Information System (INIS)

Konings, Piet

2005-01-01

Recent studies of African boundaries have tended to focus either on the growing number of border disputes between states or on frontier regions that are said to offer local inhabitants a wide range of economic opportunities. This article attempts to combine both approaches and to demonstrate the ambiguous nature of the Anglophone Cameroon-Nigeria border. On the one hand, the border has been subject to regular skirmishes between Cameroon and Nigeria, culminating in a protracted war over the sovereignty of the Bakassi peninsula - an area rich in oil reserves. On the other hand, it has for historical and economic reasons never constituted a real barrier to cross-border movements of labour and goods. The large Nigerian migrant community in Anglophone Cameroon, in particular, has been able to benefit from formal and informal cross-border trade for a long time. Unsurprisingly, its dominant position in the host community's commercial sector has been a continuous source of conflict. (Author)

Cameroon's national literatures: An introduction

African Journals Online (AJOL)

2016-03-28

Mar 28, 2016 ... In the Afterword of my book The Sacred Door and Other Stories: .... (Cameroon National Union) in 1966, and declared a unitary state in 1972 known as ... censorship, and to the general feeling of hopelessness of the 2000s.

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

Upper Triassic mafic dykes of Lake Nyos, Cameroon (West Africa) I: K-Ar age evidence within the context of Cameroon Line magmatism, and the tectonic significance

Science.gov (United States)

Aka, Festus Tongwa; Hasegawa, Takeshi; Nche, Linus Anye; Asaah, Asobo Nkengmatia Elvis; Mimba, Mumbfu Ernestine; Teitchou, Isidore; Ngwa, Caroline; Miyabuchi, Yasuo; Kobayashi, Tetsuo; Kankeu, Boniface; Yokoyama, Tetsuya; Tanyileke, Gregory; Ohba, Takeshi; Hell, Joseph Victor; Kusakabe, Minoru

2018-05-01

The hydrodynamic fragmentation that formed Lake Nyos in northwest Cameroon did not only make it the most unpopular lake in the world from a gas disaster perspective, it also opened a rare and formidable window through which much of the geology of Cameroon can be studied in a single locality. The Cambrian quartz monzonite cliff excavated by the maar-forming explosion and exposed in its northeastern shore is intruded by mafic dykes, two of which we dated. Even though close to one another, the dykes are different in composition. The alkaline dyke yields a slightly older (Carnian) K-Ar fedspar age of 231.1 ± 4.8 Ma, while the sub alkaline dyke yields an age of 224.8 ± 4.7 Ma (Norian). Based on radioisotopic age data available over the last 48 years (347 data) for the Cameroon Line magmatism comprising eruptives and volcano-plutonic complexes, the Nyos dykes are way older than the Cameroon Line, and even pre-date the Lower Cretaceous initiation of west Gondwana fragmentation in Equatorial Atlantic domain. They would therefore not have been directly linked to the formation of the Cameroon Line. Alternatively, they might be associated with the development of intra-continental rift systems in West Central Africa that pre-dated west Gondwana breakup to form the Atlantic Ocean.

Mapping for Health in Cameroon: Polio Legacy and Beyond.

Science.gov (United States)

Rosencrans, Louie C; Sume, Gerald E; Kouontchou, Jean-Christian; Voorman, Arend; Anokwa, Yaw; Fezeu, Maurice; Seaman, Vincent Y

2017-07-01

During the poliovirus outbreak in Cameroon from October 2013 to April 2015, the Ministry of Public Health's Expanded Program on Immunization requested technical support to improve mapping of health district boundaries and health facility locations for more effective planning and analysis of polio program data. In December 2015, teams collected data on settlements, health facilities, and other features using smartphones. These data, combined with high-resolution satellite imagery, were used to create new health area and health district boundaries, providing the most accurate health sector administrative boundaries to date for Cameroon. The new maps are useful to and used by the polio program as well as other public health programs within Cameroon such as the District Health Information System and the Emergency Operations Center, demonstrating the value of the Global Polio Eradication Initiative's legacy. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America.

Does malaria epidemiology project Cameroon as

Indian Academy of Sciences (India)

2014-07-16

Jul 16, 2014 ... migration from the rural to urban areas as well as population exchange with adjoining countries, high ... cultural practices, deforestation, etc., have also resulted in ..... (Cameroon): influence of urban agriculture and pollution.

The Dilemma of Civil Society in Cameroon Since 1990: Which Way ...

African Journals Online (AJOL)

sulaiman.adebowale

2008-04-09

Apr 9, 2008 ... of civil society when it has an impact on the society; if not it should be left out. .... campaign and the post-October 1992 election results. As a matter of ... from the General Agreement on Tariffs (GATT) text on Cameroon. ..... Nyamnjoh, F. B., 1997, 'Media, Tribalism and Democracy in Cameroon, in Gerddes,.

TROPFOMS, a decision support model for sustainabele management of south Cameroon's rainforests

NARCIS (Netherlands)

Eba'a Atyi, R.

2000-01-01

Natural forests play an important role in the economy of Cameroon, at both the national and local levels. Unfortunately, there is still a general sense that in Cameroon, like in most tropical countries, forests are not managed in a sustainable way. The poor forest management practices,

Thanking Responders in Cameroon English

Science.gov (United States)

Ouafeu, Yves Talla Sando

2009-01-01

An analysis of authentic or genuine interactions among Cameroon English speakers reveals that conversational routines in this variety of English differ a good deal from those obtained in other varieties of English, non-native varieties of English inclusive, and more specifically in native varieties of English. This paper looks at "thanking…

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…

Recruitment Of International Students Into Cameroon Tertiary ...

African Journals Online (AJOL)

Recruitment Of International Students Into Cameroon Tertiary Institutions In The Absence Of International Offices. ... The present system of recruiting international students is haphazardly been handled by ... AJOL African Journals Online.

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

African Journals Online (AJOL)

African Journal of Environmental Science and Technology ... sector, and proffers a series of policy recommendations for advancing sustainable forest management in ... Since the enactment of Cameroon's comprehensive forestry law (Law N0.

Pro Poor Growth in Cameroon

Directory of Open Access Journals (Sweden)

Samuel Fambon

2017-06-01

Full Text Available The purpose of this paper is to analyze the relationship between economic growth, poverty and income distribution in Cameroon, using both the data derived from three Cameroonian household surveys and the Poverty Equivalent Growth Rate (PEGR methodology developed by Kakwani et al. (2004, The study found that economic growth in Cameroon was pro poor over the period 1996–2007, which suggests that instead of increasing the economic growth rate alone, the poverty equivalent growth rate should also be maximized to achieve the poverty reduction objective, meaning that on the one hand, the growth rate should be boosted, and on the other, the distribution of income should also be concurrently improved. A decomposition of changes in poverty using the Kakwani (1997 approach reveal that the growth component dominates the redistribution component in the reduction of poverty. This suggests that the fall in absolute poverty over the survey period may be attributed to an increase in average household income, and not to the redistributive policies of the government.

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.

Causality analysis of diesel consumption and economic growth in Cameroon

International Nuclear Information System (INIS)

Tamba, Jean Gaston; Njomo, Donatien; Limanond, Thirayoot; Ntsafack, Borel

2012-01-01

This study examines the causal relationship between diesel consumption and economic growth in Cameroon by using a three-step modern time-series technique. Tests for unit roots, cointegration, and Granger-causality based on error correction model are employed on annual data covering the period 1975–2008. Empirical results of the study confirm the presence of a long-run equilibrium relationship between diesel consumption and economic growth. The error correction model shows that an estimated 1% increase in economic growth causes a rise in diesel consumption of 1.30% in the long-run. The overall results show that there exists bidirectional causality in the long-run relationship and no causality in the short-run relationship between diesel consumption and economic growth at the 5% level of significance. Thus, the energy policies in Cameroon should place priority on the discovery of new oil field and building capacity additions of the refinery to increase production of petroleum products, as this would propel the economic growth of the country. - Highlights: ► We examine the causal relationship between diesel consumption and GDP in Cameroon. ► we analyze the petroleum products sector in Cameroon. ► 1% increase in economic growth causes a rise in diesel consumption of 1.30%. ► The policy aimed at improving diesel supply have a positive impact on economics.

A multi-perspective view of genetic variation in Cameroon.

Science.gov (United States)

Coia, V; Brisighelli, F; Donati, F; Pascali, V; Boschi, I; Luiselli, D; Battaggia, C; Batini, C; Taglioli, L; Cruciani, F; Paoli, G; Capelli, C; Spedini, G; Destro-Bisol, G

2009-11-01

In this study, we report the genetic variation of autosomal and Y-chromosomal microsatellites in a large Cameroon population dataset (a total of 11 populations) and jointly analyze novel and previous genetic data (mitochondrial DNA and protein coding loci) taking geographic and cultural factors into consideration. The complex pattern of genetic variation of Cameroon can in part be described by contrasting two geographic areas (corresponding to the northern and southern part of the country), which differ substantially in environmental, biological, and cultural aspects. Northern Cameroon populations show a greater within- and among-group diversity, a finding that reflects the complex migratory patterns and the linguistic heterogeneity of this area. A striking reduction of Y-chromosomal genetic diversity was observed in some populations of the northern part of the country (Podokwo and Uldeme), a result that seems to be related to their demographic history rather than to sampling issues. By exploring patterns of genetic, geographic, and linguistic variation, we detect a preferential correlation between genetics and geography for mtDNA. This finding could reflect a female matrimonial mobility that is less constrained by linguistic factors than in males. Finally, we apply the island model to mitochondrial and Y-chromosomal data and obtain a female-to-male migration Nnu ratio that was more than double in the northern part of the country. The combined effect of the propensity to inter-populational admixture of females, favored by cultural contacts, and of genetic drift acting on Y-chromosomal diversity could account for the peculiar genetic pattern observed in northern Cameroon.

JOURNAL, OF THE CAMEROON ACADEMY OFSCII:NCES

African Journals Online (AJOL)

Institute of Agronomic Research for development (IRAD) Box 33 Maroua, Cameroon;. E-maîl: rckenga(Gºyahoo. ... genetic transformation (Arriola, 1995). The continued ..... Grenier, C., Bramel-Cox, P.J., and P. Hamon. 2001. Core collection of ...

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

African Journals Online (AJOL)

EJIRO

passed to facilitate the implementation of this law. (Oyono, 2004; Alemagi ... to be responsible for their negative environmental impacts and offers a vision for ... socio-economic sustainability within the forestry sector in. Cameroon, it is important ...

Regulation of Biotechnology in Cameroon W

African Journals Online (AJOL)

... security and public health are high on government's policy agenda. ... tion by the Cameroon Development Corporation. (CDC) of a ... can model law on Safety in Biotechnology (and the Convention ..... its biosafety regulation on liability and redress in due course. ... in Kuala Lumpur, Malaysia in February this year. (2004).

Homosexuality in Cameroon: identity and persecution

NARCIS (Netherlands)

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

2010-01-01

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

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 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.

Women and Economic Development in Cameroon.

Science.gov (United States)

Bryson, Judy C.

Based on a survey of written sources and perspectives of knowledgeable individuals, the report provides information on women's economic roles in Cameroon, and on aspects of social life which effect their economic performance. A description of the importance of traditional social systems and their evolution over the last 30 years follows a brief…

Vegetable Consumption patterns in Yaounde, Cameroon | Kamga ...

African Journals Online (AJOL)

A survey was conducted in August and September 2008 in Yaoundé, Cameroon to assess vegetable consumption attitudes, constraints and factors that stimulate households' consumption. Stratified sample based on district size, socioeconomic status and ethnics groups were used. Three hundred households were ...

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.

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.

Stable Isotopic Composition of Rainfall in Western Cameroon

Energy Technology Data Exchange (ETDEWEB)

Ketchemen-Tandia, B.; Ngo Boum, S.; Ebonji Seth, C. R.; Nkoue Ndong, G. R.; Wonkam, C. [Universite de Douala, Douala (Cameroon); Huneau, F. [Universite de Bordeaux, EA Georessources and Environnement, Talence (France); Celle-Jeanton, H. [Clermont Universite, Clermont-Ferrand (France)

2013-07-15

Monthly rainfall collected at the douala station (Western cameroon) from 2006 to 2008 was analysed for oxygen-18 and deuterium content. The dataset, which is now integrated into the GNIP database, was compared to the local groundwater record in order to define the input function of regional hydrosystems. The isotope data displays a wide range of values from -0.59 to -6.14 per mille for oxygen-18 and from -7.75 to -38.8 per mille for deuterium, closely following the GMWL (global Meteoric Water line), suggesting that rain formation processes occurred under isotopic equilibrium conditions between the condensate and the corresponding vapour. No significant evaporation tendency was found. The comparison with the previous studies in the area provides a realistic pattern of isotope concentrations in both surface and groundwater throughout Cameroon. (author)

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.

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.

ON THE SUSTAINABILITY OF CURRENT ACCOUNT DEFICITS IN CAMEROON

Directory of Open Access Journals (Sweden)

Edouard T. Djeutem

2013-04-01

Full Text Available Two approaches are used to analyze the sustainability of the current account deficits of Cameroon in order to find out whether current economic policies are sound enough to guarantee the country’ s financial solvency. The first uses a structural procedure to compare current account deficits relative to an optimal benchmark using the Campbell-Shiller’s methodology. The second uses a reduced form approach to test for intertemporal budget constraint through cointegration tests between imports and exports plus net transfer payments on foreign obligations. Our results suggest that the current account imbalances for Cameroon based on data from the period 1970-2002 are “excessive” and the deficits are currently unsustainable.

Local Rulers in North Cameroon. The Interplay of Politics and Conversion

Directory of Open Access Journals (Sweden)

Kees Schilder

1993-03-01

Full Text Available This article analyses the conversion to Islam of indigenous chiefs in North Cameroon. The chiefs studied belong to the Mundang ethnic group. Their islamisation is interpreted as the outcome of the ambivalence brought about by their intermediary role between local society and the wider society. This approach offers insights in (a the connection between conversion and political careers; (b the relation between Islam and ethnic identities; and (c the popular legitimacy of conversion. KEY WORDS: Cameroon, Mundang, chiefs, Islam, ethnicity, cosmology

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.

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 ...

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.

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.

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....

[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%.

Phylogenic analysis of human bocavirus detected in children with acute respiratory infection in Yaounde, Cameroon.

Science.gov (United States)

Kenmoe, Sebastien; Vernet, Marie-Astrid; Njankouo-Ripa, Mohamadou; Penlap, Véronique Beng; Vabret, Astrid; Njouom, Richard

2017-07-17

Human Bocavirus (HBoV) was first identified in 2005 and has been shown to be a common cause of respiratory infections and gastroenteritis in children. In a recent study, we found that 10.7% of children with acute respiratory infections (ARI) were infected by HBoV. Genetic characterization of this virus remains unknown in Central Africa, particularly in Cameroon Leeding us to evaluate the molecular characteristics of HBoV strains in Cameroonian children with ARI. Phylogenetic analysis of partial HBoV VP1/2 sequences showed a low level of nucleotide variation and the circulation of HBoV genotype 1 (HBoV-1) only. Three clades were obtained, two clustering with each of the reference strains ST1 and ST2, and a third group consisting of only Cameroon strains. By comparing with the Swedish reference sequences, ST1 and ST2, Cameroon sequences showed nucleotide and amino acid similarities of respectively 97.36-100% and 98.35-100%. These results could help improve strategies for monitoring and control of respiratory infections in Cameroon.

Sexual risk behaviours of high school female learners in Mbonge subdivision of rural Cameroon.

Science.gov (United States)

Tarkang, Elvis Enowbeyang

2015-01-01

Since female learners in high schools in Cameroon fall within the age group hardest hit by HIV/AIDS, it is assumed that these learners might be exposed to sexual risk behaviours. However, little has been explored on the sexual risk behaviours of high school female learners in Cameroon. This study aimed at examining the sexual risk behaviours of high school female learners in Mbonge subdivision of rural Cameroon. A cross sectional design was adopted, using a self-administered questionnaire for data collection. Respondents were selected through disproportional stratified simple random sampling resulting in 210 female grade 10 to grade 12 learners from three participating high schools in Mbonge subdivision, Cameroon. Descriptive and inferential statistics were calculated using SPSS version 20 software program. Majority of the respondents, 54.0% reported being sexually active, of whom only 39.8% used condoms during first sex; 49.5% used condoms during last sex and 29.6% used condoms consistently. Up to 32% of the sexually active respondents had multiple sexual partners in the past one year before the study, while 9.3% had multiple sexual partners during the study period. The mean age of first sex was 15.6 years. Lack of parental control, religion, academic profile, poverty, place of residence and perception of risk of HIV infection were the main factors significantly associated with sexual risk behaviours. The findings indicate that sexual risk behaviours exist among high school female learners in Mbonge, Cameroon. There is need for campaigns and interventions to bring about sexual behaviour change.

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 ...

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

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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.

Perception of the Environmental Degradation of Gold Mining on Socio-Economic Variables in Eastern Cameroon, Cameroon

OpenAIRE

Marc Anselme Kamga; Charles Olufisayo Olatubara; Moses Monday Atteh; Serge Nzali; Adeola Adenikinju; Théodore Yimgnia Mbiatso; Ralain Bryan Ngatcha

2018-01-01

Artisanal mining is associated with a number of environmental impacts, including deforestation and land degradation, open pits which pose animal traps and health hazards, and heavy metals contamination of land (water and soil), dust and noise pollution. The study examines the perception of environmental degradation of gold mining sites in eastern Cameroon. Human-environment interaction and distance decay models are the conceptual framework for this study.  This study employed a survey re...

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

African Journals Online (AJOL)

ISHIOMA

A level III fugacity model was developed to evaluate the fate of chemicals in the Cameroon ... environment, quantify intermedia transfer processes and the major loss ... perform baseline exposure and risk assessment of chemicals used in ...

Writing in Cameroon, the first hundred years

African Journals Online (AJOL)

2016-03-28

Mar 28, 2016 ... in Bulu territory, the American pastor Adolphus Good, it won the London African .... same year, Le Vieux Nègre et la médaille is a critique of the vieux nègre (old black man), .... Cameroon, cautious editorial choices and writers' self-censorship, a limited range of ... many also used film and other media.

Production performance and exploitation of heterosis in Cameroon ...

African Journals Online (AJOL)

A crossbreeding experiment using Cameroon indigenous (CF) and German Dahlem Red (GR) chickens was undertaken to determine production performance and heterosis estimates of body weight of cockerels and laying hens at various ages and and egg production traits in layers. Four genetic groups were involved, ...

Occupation of public space : anglophone nationalism in Cameroon

NARCIS (Netherlands)

Jua, N.; Konings, P.J.J.

2004-01-01

This article examines the historical process leading to the emergence of Anglophone nationalism in public space during the liberalisation process in the 1990s in Cameroon. Anglophone nationalism poses a severe threat to the post-colonial State's nation-building project that has been driven by the

THE PLIGHT OF GERMAN MISSIONS IN MANDATE CAMEROON: AN HISTORICAL ANALYSIS

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Lang Michael Kpughe

2017-09-01

Full Text Available The First World War and its resultant Mandate and Trusteeship systems greatly affected the German mission enterprise in Cameroon. Apart from causing the forceful ousting of German missionaries from Cameroon, the British and the French whom the League of Nations and United Nations successively chose as administering powers within the Mandate and Trusteeship frameworks adopted hostile policies towards German missions. From the beginning of the war to the post-Second World War era, the foundation of German missions was seriously threatened. This paper critically examines the treatment of German missions in both British and French Cameroons during the Mandate and Trusteeship periods, focusing especially on the opposing attitudes of both administering powers towards the missions in their spheres of influence. The paper establishes that the administering powers’ treatment of German missions, which was underpinned by imperial and nationalist exigencies, roiled the attainment of the triple missionization agenda of planting self-supporting, self-governing and self-evangelizing churches. It thus argues that the First World War triggered the mistreatment of German missions, with some missions forced to terminate their activities while others were allowed to continue their mission work under difficult conditions.

Pesticides use in cocoa sector in Cameroon: characterization of ...

African Journals Online (AJOL)

International Journal of Biological and Chemical Sciences ... Journal Home > Vol 8, No 5 (2014) > ... The chemical control is the widely control method applied in Cameroon for pests and diseases by all the cocoa producers without technical ...

Dentofacial injuries in commercial motorcycle accidents in Cameroon

African Journals Online (AJOL)

Objective: To assess the pattern of dentofacial injuries in commercial motorcycle accidents among riders and passengers in Cameroon. Materials and Methods: This was a hospital based study conducted in 6 out of 10 regional capitals in the months of December 2011 to September 2012. Analyzed information included age, ...

Factors affecting livestock predation by lions in Cameroon

NARCIS (Netherlands)

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

2007-01-01

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

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

African Journals Online (AJOL)

2008-12-11

Dec 11, 2008 ... However, different predictions of monetary theories have assigned different degrees of .... Sources: World Bank, World Table, Cameroon Financial Bill 2007, and African Development Indicators. ..... of Accounting and Statistics.

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

Science.gov (United States)

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

2010-01-01

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

Simulation of off-grid generation options for remote villages in Cameroon

International Nuclear Information System (INIS)

Nfah, E.M.; Ngundam, J.M.; Vandenbergh, M.; Schmid, J.

2008-01-01

Off-grid generation options have been simulated for remote villages in Cameroon using a load of 110 kWh/day and 12 kWp. The energy costs of proposed options were simulated using HOMER, a typical village load profile, the solar resource of Garoua and the flow of river Mungo. For a 40% increase in the cost of imported power system components, the cost of energy was found to be 0.296 EUR/kWh for a micro-hydro hybrid system comprising a 14 kW micro-hydro generator, a 15 kW LPG generator and 36 kWh of battery storage. The cost of energy for photovoltaic (PV) hybrid systems made up of an 18 kWp PV generator, a 15 kW LPG generator and 72 kWh of battery storage was also found to be 0.576 EUR/kWh for remote petrol price of 1 EUR/l and LPG price of 0.70 EUR/m 3 . The micro-hydro hybrid system proved to be the cheapest option for villages located in the southern parts of Cameroon with a flow rate of at least 200l/s, while the PV hybrid system was the cheapest option for villages in the northern parts of Cameroon with an insolation level of at least 5.55 kWh/m 2 /day. For a single-wire grid extension cost of 5000 EUR/km, operation and maintenance costs of 125 EUR/yr/km and a local grid power price of 0.1 EUR/kWh, the breakeven grid extension distances were found to be 15.4 km for micro-hydro/LPG generator systems and 37.4 km for PV/LPG generator systems respectively. These results could be used in Cameroon's National Energy Action Plan for the provision of energy services in the key sectors involved in the fight against poverty. (author)

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

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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.

Implications of the Bakassi conflict resolution for Cameroon | Baye ...

African Journals Online (AJOL)

This paper sketches a conceptual framework of international conflict dynamics and resolution, examines the geopolitics of the Bakassi dispute between Nigeria and Cameroon, and outlines socio-economic implications of its peaceful settlement. Neglect and subsequent discovery of oil deposits subjected the Bakassi ...

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

African Journals Online (AJOL)

Abstract This paper deals with the accurate determination of mount Cameroon orthometric height, by combining ground gravity data, global navigation satellite system (GNSS) observations and global geopotential models. The elevation of the highest point (Fako) is computed above the WGS84 reference ellipsoid.

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

African Journals Online (AJOL)

Money Supply, Interest Rate, and Economic Growth in Cameroon: A Time Series ... the impacts of money and interest rate on economic growth and development. ... Money Supply, Interest Rates, Economic growth, Co-integration and Inflation.

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

African Journals Online (AJOL)

Perpetua Lum Tanyi

2018-02-06

Feb 6, 2018 ... ... social policy are discussed. Keywords: HIV/AIDS, older adults, African family, caregiving, Cameroon ...... and treatment that may be spread out over the full period of illness. ..... anxiety, relationships, grief, loss and addictions.

New attitudes key to progress in Malawi, Cameroon | IDRC ...

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

2011-11-08

Nov 8, 2011 ... New attitudes key to progress in Malawi, Cameroon ... in Malawi — good laws protecting women's rights — but they are not working. Why? ... Colonial rule — first by the Germans and later the French and British — brought in a ...

Floodplain rehabilitation in North Cameroon: impact on vegetation dynamics

NARCIS (Netherlands)

Scholte, P.; Kirda, P.; Adam, S.; Kadiri, B.

2000-01-01

Since the construction in 1979 of a dam in the Logone floodplain in the Sahelo-Sudanian zone of Cameroon, annual inundations have decreased, reducing perennial vegetation as important grazing source for nomadic herds and wildlife during the dry season. Presently, possibilities exist to release

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

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Basile Kamgang

Full Text Available 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 < 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.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.

Seroprevalence of Human Herpesvirus-8 in HIV-1 Infected and Uninfected Individuals in Cameroon

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Owen Wood

2013-09-01

Full Text Available We evaluated the prevalence of HHV-8 antibodies in 516 plasma samples collected from HIV positive and negative patients from blood banks and urban areas of Cameroon. Among HIV-1 positive samples, HHV-8 seropositivity rate was 61% based on combined reactivity using both ELISA and IFA techniques. HIV negative samples showed 62% seropositivity rate for HHV-8 antibodies. Our results indicate a high HHV-8 prevalence rate in both HIV infected and uninfected individuals in Cameroon.

Volcanism on Io

Science.gov (United States)

Davies, Ashley Gerard

2014-03-01

Preface; Introduction; Part I. Io, 1610 to 1995: Galileo to Galileo: 1. Io, 1610-1979; 2. Between Voyager and Galileo: 1979-95; 3. Galileo at Io; Part II. Planetary Volcanism: Evolution and Composition: 4. Io and Earth: formation, evolution, and interior structure; 5. Magmas and volatiles; Part III. Observing and Modeling Volcanic Activity: 6. Observations: thermal remote sensing of volcanic activity; 7. Models of effusive eruption processes; 8. Thermal evolution of volcanic eruptions; Part IV. Galileo at Io: the Volcanic Bestiary: 9. The view from Galileo; 10. The lava lake at Pele; 11. Pillan and Tvashtar: lava fountains and flows; 12. Prometheus and Amirani: Effusive activity and insulated flows; 13. Loki Patera: Io's powerhouse; 14. Other volcanoes and eruptions; Part V. Volcanism on Io: The Global View: 15. Geomorphology: paterae, shields, flows and mountains; 16. Volcanic plumes; 17. Hot spots; Part VI. Io after Galileo: 18. Volcanism on Io: a post-Galileo view; 19. The future of Io observations; Appendix 1; Appendix 2; References; Index.

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 ...

Comparison of bacterial communities of tilapia fish from Cameroon ...

African Journals Online (AJOL)

Comparison of bacterial communities of tilapia fish from Cameroon and Vietnam using PCR-DGGE (polymerase chain reaction-denaturing gradient gel electrophoresis) ... The different PCR-DGGE 16S rDNA banding profiles obtained were analysed and results showed that there were specific bands for each geographical ...

Initiatives supporting evidence informed health system policymaking in Cameroon and Uganda: a comparative historical case study.

Science.gov (United States)

Ongolo-Zogo, Pierre; Lavis, John N; Tomson, Goran; Sewankambo, Nelson K

2014-11-29

There is a scarcity of empirical data on institutions devoted to knowledge brokerage and their influence in Africa. Our objective was to describe two pioneering Knowledge Translation Platforms (KTPs) supporting evidence informed health system policymaking (EIHSP) in Cameroon and Uganda since 2006. This comparative historical case study of Evidence Informed Policy Network (EVIPNet) Cameroon and Regional East African Community Health Policy Initiative (REACH-PI) Uganda using multiple methods comprised (i) a descriptive documentary analysis for a narrative historical account, (ii) an interpretive documentary analysis of the context, profiles, activities and outputs inventories and (iii) an evaluative survey of stakeholders exposed to evidence briefs produced and policy dialogues organized by the KTPs. Both initiatives benefited from the technical and scientific support from the global EVIPNet resource group. EVIPNet Cameroon secretariat operates with a multidisciplinary group of part-time researchers in a teaching hospital closely linked to the ministry of health. REACH-PI Uganda secretariat operates with a smaller team of full time staff in a public university. Financial resources were mobilized from external donors to scale up capacity building, knowledge management, and linkage and exchange activities. Between 2008 and 2012, twelve evidence briefs were produced in Cameroon and three in Uganda. In 2012, six rapid evidence syntheses in response to stakeholders' urgent needs were produced in Cameroon against 73 in Uganda between 2010 and 2012. Ten policy dialogues (seven in Cameroon and three in Uganda) informed by pre-circulated evidence briefs were well received. Both KTPs contributed to developing and testing new resources and tools for EIHSP. A network of local and global experts has created new spaces for evidence informed deliberations on priority health policy issues related to MDGs. This descriptive historical account of two KTPs housed in government

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

African Journals Online (AJOL)

kemrilib

The review found that in Cameroon women were at increased risk of being infected with HIV/AIDS ... the high prevalence of HIV/AIDS among women. However ...... (Assessed 10 March 2006). 2. .... Prevention. Washington DC 1999: pp 1-7. 45.

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 ...

Analysis of Cameroon newspaper coverage of cross border conflicts

African Journals Online (AJOL)

Nexus of conflict reporting: Analysis of Cameroon newspaper coverage of cross ... The conflicts taking place in the Central African Republic, Chad, Nigeria and Gabon have raised ... Consequently, it is in the interest of the public .... of Humanitarian Affairs (OCHA, 2014), ... As what concerns the case of Nigeria, UNHCR.

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 ...

Measles outbreak in a poorly vaccinated region in Cameroon: a ...

African Journals Online (AJOL)

preventable deaths in Africa; especially in unvaccinated populations. We reviewed the medical reports of the measles outbreak that occurred in Misaje, in the North west region of Cameroon from 11/03/2015 to 14/05/2015. Six measles cases ...

Structure of the crust beneath Cameroon, West Africa, from the joint inversion of Rayleigh wave group velocities and receiver functions

Science.gov (United States)

Tokam, Alain-Pierre K.; Tabod, Charles T.; Nyblade, Andrew A.; Julià, Jordi; Wiens, Douglas A.; Pasyanos, Michael E.

2010-11-01

The Cameroon Volcanic Line (CVL) consists of a linear chain of Tertiary to Recent, generally alkaline, volcanoes that do not exhibit an age progression. Here we study crustal structure beneath the CVL and adjacent regions in Cameroon using 1-D shear wave velocity models obtained from the joint inversion of Rayleigh wave group velocities and P-receiver functions for 32 broad-band seismic stations deployed between 2005 January and 2007 February. We find that (1) crustal thickness (35-39km) and velocity structure is similar beneath the CVL and the Pan African Oubanguides Belt to the south of the CVL, (2) crust is thicker (43-48km) under the northern margin of the Congo Craton and is characterized by shear wave velocities >=4.0kms-1 in its lower part and (3) crust is thinner (26-31km) under the Garoua rift and the coastal plain. In addition, a fast velocity layer (Vs of 3.6-3.8kms-1) in the upper crust is found beneath many of the seismic stations. Crustal structure beneath the CVL and the Oubanguides Belt is very similar to Pan African crustal structure in the Mozambique Belt, and therefore it appears not to have been modified significantly by the magmatic activity associated with the CVL. The crust beneath the coastal plain was probably thinned during the opening of the southern Atlantic Ocean, while the crust beneath the Garoua rift was likely thinned during the formation of the Benue Trough in the early Cretaceous. We suggest that the thickened crust and the thick mafic lower crustal layer beneath the northern margin of the Congo Craton may be relict features from a continent-continent collision along this margin during the formation of Gondwana.

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

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

Smoke-Free Worksites and Public Spaces in Cameroon. Existing data indicate a tobacco epidemic of the first order in Africa, but the rapid increase in tobacco consumption continues. This situation justifies the current project by Research for International Tobacco Control (RITC), an initiative of IDRC and the Bill and Melinda ...

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

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. CD 4 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 CD 4 counts between 200 and 500 cells/μl of 42.5%, and subjects with CD 4 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.

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.

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.

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

Indian Academy of Sciences (India)

Cameroon, a west-central African country with a ∼20 million population, is commonly regarded as 'Africa in miniature' due to the extensive biological and cultural diversities of whole Africa being present in a single-country setting. This country is inhabited by ancestral human lineages in unique eco-climatic conditions and ...

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

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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

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

The Fallacy of Promoting Non Native Varieties of English in Postcolonial Multilingual Settings: The Case of Cameroon English (CamE) in Cameroon

Science.gov (United States)

Essossomo, Serges Moïse

2015-01-01

This research endeavour is a major contribution to the current debate on the integration of non-native varieties into the school curriculum in non-native settings. Taking the specific case of Cameroon, this work rests on the solid assumption that the promotion of CamE to the detriment of Standard British English accent is definitely a fallacy. The…

Rivers and ports in transport history of Cameroon, 1916-1961 | Nkwi ...

African Journals Online (AJOL)

Rivers and ports in transport history of Cameroon, 1916-1961. ... rivers and ports for their physical mobility, transportation of bulky goods, mails migration and above all European consumer ... EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT

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

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

Volcanic stratigraphy: A review

Science.gov (United States)

Martí, Joan; Groppelli, Gianluca; Brum da Silveira, Antonio

2018-05-01

Volcanic stratigraphy is a fundamental component of geological mapping in volcanic areas as it yields the basic criteria and essential data for identifying the spatial and temporal relationships between volcanic products and intra/inter-eruptive processes (earth-surface, tectonic and climatic), which in turn provides greater understanding of the geological evolution of a region. Establishing precise stratigraphic relationships in volcanic successions is not only essential for understanding the past behaviour of volcanoes and for predicting how they might behave in the future, but is also critical for establishing guidelines for exploring economic and energy resources associated with volcanic systems or for reconstructing the evolution of sedimentary basins in which volcanism has played a significant role. Like classical stratigraphy, volcanic stratigraphy should also be defined using a systematic methodology that can provide an organised and comprehensive description of the temporal and spatial evolution of volcanic terrain. This review explores different methods employed in studies of volcanic stratigraphy, examines four case studies that use differing stratigraphic approaches, and recommends methods for using systematic volcanic stratigraphy based on the application of the concepts of traditional stratigraphy but adapted to the needs of volcanological environment.

The Impact Of Dental Auxiliaries In Oral Health Delivery In Cameroon

African Journals Online (AJOL)

treat 6-10 patients per day while 13 (29.5%) of respondents work without any direct supervision. Out of ... the training and job description of dental auxiliaries in Cameroon. Introduction .... A Textbook for Preventive and. Community Dentistry.

Ritual use of currency in Laimbwe history, Cameroon | Kah | Lwati: A ...

African Journals Online (AJOL)

Ritual use of currency in Laimbwe history, Cameroon. ... exchange and a measurement of value to replace other indigenous currencies, had an impact ... social classes and the re-enforcement of the socio-political order of the Laimbwe people.

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 ...

Financing Of Small And Medium-Size Enterprises In Cameroon ...

African Journals Online (AJOL)

Financing Of Small And Medium-Size Enterprises In Cameroon. ... Available data from the banking sector shows that as much as 78.7% of all ... SMEs and large companies pay back their loans better than the other ... Even the SME loan repayment rate of 62.9% is still low by World Bank ... AJOL African Journals Online.

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

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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.

Gynaecological morbidity among HIV positive pregnant women in Cameroon

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Nana Philip N

2008-07-01

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

The Origin of Widespread Long-lived Volcanism Across the Galapagos Volcanic Province

Science.gov (United States)

O'Connor, J. M.; Stoffers, P.; Wijbrans, J. R.; Worthington, T. J.

2005-12-01

40Ar/39Ar ages for rocks dredged (SO144 PAGANINI expedition) and drilled (DSDP) from the Galapagos Volcanic Province (Cocos, Carnegie, Coiba and Malpelo aseismic ridges and associated seamounts) show evidence of 1) increasing age with distance from the Galapagos Archipelago, 2) long-lived episodic volcanism at many locations, and 3) broad overlapping regions of coeval volcanism. The widespread nature of synchronous volcanism across the Galapagos Volcanic Province (GVP) suggests a correspondingly large Galapagos hotspot melting anomaly (O'Connor et al., 2004). Development of the GVP via Cocos and Nazca plate migration and divergence over this broad melting anomaly would explain continued multiple phases of volcanism over millions of years following the initial onset of hotspot volcanism. The question arising from these observations is whether long-lived GVP episodic volcanism is equivalent to `rejuvenescent' or a `post-erosional' phase of volcanism that occurs hundreds of thousands or million years after the main shield-building phase documented on many mid-plate seamount chains, most notably along the Hawaiian-Emperor Seamount Chain? Thus, investigating the process responsible for long-lived episodic GVP volcanism provides the opportunity to evaluate this little understood process of rejuvenation in a physical setting very different to the Hawaiian-Emperor Chain (i.e. on/near spreading axis versus mid-plate). We consider here timing and geochemical information to test the various geodynamic models proposed to explain the origin of GVP hotspot volcanism, especially the possibility of rejuvenated phases that erupt long after initial shield-building.

The protection of juveniles under Cameroon criminal law and procedures through the lens of international standards

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Thomas Ojong

2017-10-01

Full Text Available While the legislative framework on the adminitration of juvenile justice in Cameroon may currently be adequate and in compliance with the international conventions ratified by the State, the implementation of the national law should be the primary mechanism through which human rights are realized. Cameroon is usually said to be a State with good laws but poor implementation. With recourse to the normative and empirical methods, this article explores the provisions on the protection of juveniles in Cameroon criminal law and procedures through the lens of internationally recognized principles. It looks at the provisions as they are interpreted and applied by the Courts. The prospect being to invite the Government and all the stakeholders to embark on establishing the structures provided for and ensure effectiveness in the enforcement of juvenile justice in the country so as to overcome the current weaknesses that the system is experiencing.

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

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S Tabe

2012-03-01

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

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

Audiovisual translation in Cameroon: An Analysis of Voice-over in ...

African Journals Online (AJOL)

Cameroon is a multilingual country with people from different backgrounds with English and French as the official languages. The need to render information broadcast on television channels across the country to the population is accordingly of paramount importance. This can be achieved through subtitling and dubbing ...

Primarity and biometric indices of native goats in western Cameroon ...

African Journals Online (AJOL)

Goats are well integrally part of communities' livelihoods in both rural and urban regions in Cameroon. Our study intended to contribute to genetic characterization of native goats populations found in one of the highest populated region based on morphometric indices as developed by Lauvergne and COGNOSAG ...

Wealth and sexual behaviour among men in Cameroon

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Nana Philip

2006-09-01

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

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,

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

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

African Journals Online (AJOL)

The burden of human immunodeficiency virus (HIV) infection and acquired immune deficiency syndrome (AIDS) on the elderly population in three divisions within the Northwest Region of Cameroon was examined. Data for this paper were extracted from a larger study which had been conducted concerning the burden of ...

Volcanic features of Io

International Nuclear Information System (INIS)

Carr, M.H.; Masursky, H.; Strom, R.G.; Terrile, R.J.

1979-01-01

The volcanic features of Io as detected during the Voyager mission are discussed. The volcanic activity is apparently higher than on any other body in the Solar System. Its volcanic landforms are compared with features on Earth to indicate the type of volcanism present on Io. (U.K.)

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

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Henry N. Bang

2013-02-01

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

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.

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 ...

RITUAL USE OF CURRENCY IN LAIMBWE HISTORY, CAMEROON

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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.

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.

Spatial and Inter-temporal Sources of Poverty, Inequality and Gender Disparities in Cameroon: a Regression-Based Decomposition Analysis

OpenAIRE

Boniface Ngah Epo; Francis Menjo Baye; Nadine Teme Angele Manga

2011-01-01

This study applies the regression-based inequality decomposition technique to explain poverty and inequality trends in Cameroon. We also identify gender related factors which explain income disparities and discrimination based on the 2001 and 2007 Cameroon household consumption surveys. The results show that education, health, employment in the formal sector, age cohorts, household size, gender, ownership of farmland and urban versus rural residence explain household economic wellbeing; dispa...

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

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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.

Assessment of aflatoxin contamination of maize, peanut meal and poultry feed mixtures from different agroecological zones in Cameroon.

Science.gov (United States)

Kana, Jean Raphaël; Gnonlonfin, Benoit Gbemenou Joselin; Harvey, Jagger; Wainaina, James; Wanjuki, Immaculate; Skilton, Robert A; Teguia, Alexis

2013-04-29

Mycotoxins affect poultry production by being present in the feed and directly causing a negative impact on bird performance. Carry-over rates of mycotoxins in animal products are, in general, small (except for aflatoxins in milk and eggs) therefore representing a small source of mycotoxins for humans. Mycotoxins present directly in human food represent a much higher risk. The contamination of poultry feed by aflatoxins was determined as a first assessment of this risk in Cameroon. A total of 201 samples of maize, peanut meal, broiler and layer feeds were collected directly at poultry farms, poultry production sites and poultry feed dealers in three agroecological zones (AEZs) of Cameroon and analyzed for moisture content and aflatoxin levels. The results indicate that the mean of the moisture content of maize (14.1%) was significantly (P poultry in Cameroon.

Under Five Malnutrition Crises in the Boko Haram Area of Cameroon

African Journals Online (AJOL)

aDiscipline of Public Health Medicine, Department of Nursing & Public ... bUnder Privilege Children and Women Assistance (UPCAWA-SWEDEN), ... In most cases, malnutrition in its mild stage can present with no ... Other studies by the National Institute of Statistics in Cameroon .... Inpatient management of children with.

[Entomologic study of loaiasis transmission in the Lekie area (Cameroon)].

Science.gov (United States)

Demanou, M; Pion, S D; Boussinesq, M

2001-11-01

A number of cases of Loa encephalopathy have been recorded after ivermectin treatment in the Lekie Division, an area of degraded forest located in central Cameroon. An entomological study was carried out in a village of this region between May 1999 and April 2000 to determine whether the high microfilarial loads of Loa found in the population, which can exceed 10,000 microfilariae per ml of blood, were related to high densities of vector populations. The Chrysops collected at 10 catching stations, using hand nets, by persons standing by a wood fire, were dissected to evaluate their level of infection with Loa. The vectorial densities were three-fold higher in the forest stations than in those located near the habitations (2307 and 725 bites per man per year, respectively). These values are lower than those reported from similar studies in Cameroon, Congo and Gabon. Measurement of Chrysops densities does not seem to be an appropriate tool to evaluate the level of endemicity of loiasis, and to delineate the areas where there is a risk of post-ivermectin Loa encephalopathies.

The State of Dubbing in Cameroon: A Review of research on ...

African Journals Online (AJOL)

This paper examines the various studies that have been carried out in the domain of dubbing as an audiovisual translation (AVT) mode in Cameroon by Cameroonian researchers. It identifies what has been done so far, critically examines the frameworks, methods and procedures used, determines and appraises what is ...

Nuclear-derived techniques improve cattle productivity and milk quality in Cameroon

International Nuclear Information System (INIS)

Dixit, Aabha

2016-01-01

Increasing agricultural production and improving the quality of milk and meat are key to combating poverty and increasing food security in Africa. Countries such as Cameroon are increasingly turning to innovative, nuclear and nuclear-derived techniques to control and prevent diseases among livestock, and boost cattle and milk production.

Sources of Quaternary volcanism in the Itasy and Ankaratra volcanic fields, Madagascar

Science.gov (United States)

Rasoazanamparany, C.; Widom, E.; Kuentz, D. C.; Raharimahefa, T.; Rakotondrazafy, F. M. A.; Rakotondravelo, K. M.

2017-12-01

We present new major and trace element and Sr, Nd, Pb and Os isotope data for Quaternary basaltic lavas and tephra from the Itasy and Ankaratra volcanic fields, representing the most recent volcanism in Madagascar. Mafic magmas from Itasy and Ankaratra exhibit significant inter- and intra-volcanic field geochemical heterogeneity. The Itasy eruptive products range in composition from foidite to phonotephrite whereas Ankaratra lavas range from basanite to trachybasalts. Trace element signatures of samples from both volcanic fields are very similar to those of ocean island basalts (OIB), with significant enrichment in Nb and Ta, depletion in Rb, Cs, and K, and relatively high Nb/U and Ce/Pb. However, the Itasy volcanic rocks show enrichment relative to those of Ankaratra in most incompatible elements, indicative of a more enriched source and/or lower degrees of partial melting. Significant inter- and intra-volcanic field heterogeneity is also observed in Sr, Nd, Pb and Os isotope signatures. The Itasy volcanic rocks generally have less radiogenic Sr and Nd isotopic ratios but more radiogenic Pb isotopic signatures than the Ankaratra volcanic field. Together, the Itasy and Ankaratra volcanic rocks form a well-defined negative correlation in Sr vs. Pb isotopes that could be attributed to lithospheric contamination or variable degrees of mixing between distinct mantle sources. However, the lack of correlation between isotopes and indices of crustal contamination (e.g. MgO and Nb/U) are inconsistent with shallow lithospheric contamination, and instead suggest mixing between compositionally distinct mantle sources. Furthermore, although Sr-Pb isotope systematics are apparently consistent with mixing between two different sources, distinct trends in Sr vs. Nd isotopes displayed by samples from Itasy and Ankaratra, respectively, argue for more complex source mixing involving three or more sources. The current data demonstrate that although the Itasy and Ankaratra volcanic

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

Availability and conversion to energy potentials of wood-based industry residues in Cameroon

International Nuclear Information System (INIS)

Simo, A.; Siyam Siew, S.

2000-01-01

The importance of biomass as the most accessible primary energy source in Cameroon is presented. The valorization of wood wastes and residues is seen as a way of implementing the sustainable use of biomass resources. A recent survey of wood-based industries in Cameroon reveals that large volumes of industrial wood residues are generated in the rain forest areas and are inefficiently used. Important quantities are lost in the form of burning in the four main forestry provinces, while other parts of the country suffer from fuelwood shortage. With the exception of the plywood factories, the wood industry is essentially dependent on commercial energy. An analysis made to show the economic and environmental benefits of converting wood residues to energy for industrial and domestic use is presented. (author)

Energy consumption and economic growth: Evidence from Cameroon

International Nuclear Information System (INIS)

Fondja Wandji, Yris D.

2013-01-01

The aim of this paper is to study the nature of the relationship between energy consumption and economic growth in Cameroon through a three-step approach: (i) Study the stationarity of the chronic, (ii) test of causality between variables and (iii) estimate the appropriate model. The study concludes in a non-stationarity of the series. Using the data in first difference, the Granger causality test yields a strong evidence for unidirectional causality running from OIL to GDP. Cointegration tests also show that these two series are co-integrated and the Error Correction Model (ECM) reveals that every percentage increase in Oil products consumption increases economic growth by around 1.1%. This result confirms the intuition that an economic policy aimed at improving energy supply will necessarily have a positive impact on economic growth. On the other side, a lack of energy is a major bottleneck for further economic development in Cameroon. - Highlights: • The series of GDP, ELECTRICITY, OIL and BIOFUELS are integrated of order 1. • The Granger causality test yields a unidirectional causality running from OIL to GDP. • No causal link between GDP and ELECTRICITY, and no more between GDP and BIOFUELS. • Cointegration tests also show that only OIL and GDP are co-integrated. • Every percentage increase in OIL increases GDP by around 1.1%

New and little known species of ptyctimous mites (Acari, Oribatida) from Cameroon

Czech Academy of Sciences Publication Activity Database

Niedbala, W.; Starý, Josef

2014-01-01

Roč. 3889, č. 1 (2014), s. 31-57 ISSN 1175-5326 Institutional research plan: CEZ:AV0Z60660521 Institutional support: RVO:60077344 Keywords : ptyctimous mites * new species * taxonomy * morphology * Cameroon Subject RIV: EG - Zoology Impact factor: 0.906, year: 2014

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 ...

Investigation of a possible yellow fever epidemic and serosurvey for flavivirus infections in northern Cameroon, 1984.

Science.gov (United States)

Tsai, T F; Lazuick, J S; Ngah, R W; Mafiamba, P C; Quincke, G; Monath, T P

1987-01-01

A cluster of fatal hepatitis cases in northern Cameroon in 1984 stimulated a field investigation to rule out an epidemic of yellow fever. A serosurvey of villages in the extreme north of the country, in a Sudan savanna (SS) phytogeographical zone, disclosed no evidence of recent yellow fever infection. However, further south, in a Guinea savanna (GS) phytogeographical zone, serological evidence was found of endemic yellow fever virus transmission. The results indicate a potential for epidemic spread of yellow fever virus from the southern GS zone to the nothern SS zone of Cameroon, where immunity in the population was low.

Neonatal mortality in a referral hospital in Cameroon over a seven ...

African Journals Online (AJOL)

Background: The fourth Millennium Development Goals targets reduction of the mortality rate of under-fives by 2/3 by the year 2015. This reduction starts with that of neonatal mortality representing 40% of childhood mortality. In Cameroon neonatal mortality was 31% in 2011. Objectives: We assessed the trends, associated ...

Chieftaincy, labour control and capitalist development in Cameroon

OpenAIRE

Konings, P.J.J.

1996-01-01

Contrary to the studies of ethnic authorities in the Zambian and Ghanaian mines by A.L. Epstein (1958), J. Crisp (1984), and C. Lentz and V. Erlmann (1989), the present study demonstrates that chieftaincy has continued to play an important mediating role between capital and labour in estate tea production at Ndu, a small Wimbum town in the northeastern part of the Bamenda Grassfields in Cameroon, where the author conducted fieldwork in 1991. Capitalism has not yet penetrated deeply in this ar...

A predominance of hypertensive heart disease among patients with cardiac disease in buea, a semi-urban setting, South west region of cameroon

NARCIS (Netherlands)

Nkoke, Clovis; Makoge, Christelle; Dzudie, Anastase; Mfeukeu, Liliane Kuate; Luchuo, Engelbert Bain; Menanga, Alain; Kingue, Samuel

2017-01-01

Objective: The pattern of heart disease is diverse within and among world regions. The little data on the spectrum of heart disease in Cameroon has been so far limited to major cities. We sought to describe the pattern of heart disease in Buea, the South West Region of Cameroon, a semi-urban

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.

[The burden of disability in Cameroon].

Science.gov (United States)

Foti, Calogero; Albensi, Caterina; Giordani, Laura; Azeufack Ngueko, Yannick; Sanou Sobze, Martin; Colizzi, Vittorio

2017-01-01

Rehabilitation services for disabled persons are lacking in countries with limited economic resources. Reliable and objective data are needed to plan for their implementation and to determine the burden of disability in these countries. A descriptive cross-sectional study conducted in June 2013 among people living in Dschang Health District, in the West region of Cameroon, to collect information about socio-demographic aspects of physically disabled subjects and health determinants of disabilities. Data was collected using a standard questionnaire in French. In total, 159 physically disabled subjects were enrolled in the study. Mean age was 36 years [± SD 17.26], 55.9% of subjects were female, and 33.8% had a low educational-level. The most frequently reported disabilities were orthopaedic problems (mainly fractures) [45.8%], infectious diseases [29.1%]), and neurological disabilities (mainly hemiplegia [33.3%], hemiparesis [23.8%], and monoplegia [23.8%]). The main causes of disability were trauma due to traffic accidents (17.8%) and inappropriate medical interventions (14.5%). Disability was related to age and 50% of participants experienced social discrimination. Disabled subjects with low-incomes (from 50.000 to 200.000 XAF) were required to pay for rehabilitative care (XAF 10.000 to 100.000), and up to 83% had appealed for improved quality of Rehabilitation Medicine. Although Law n. 83/013 for the protection of persons with disabilities in Cameroon dates back to 1983, the results of this study show that disabled people, and children in particular, are still marginalized, vulnerable and have little chance of recovery. Therefore, there is a clear need to improve the quality and availability of rehabilitative care services , with programmatic interventions that ensure implementation of existing laws, improve access to rehabilitative services, provide disabled persons with the necessary specialty medical products, and eliminate barriers to their social

Modern bioenergy from agricultural and forestry residues in Cameroon: Potential, challenges and the way forward

International Nuclear Information System (INIS)

Ackom, Emmanuel K.; Alemagi, Dieudonne; Ackom, Nana B.; Minang, Peter A.; Tchoundjeu, Zac

2013-01-01

Environmentally benign modern bioenergy is widely acknowledged as a potential substitute for fossil fuels to offset the human dependence on fossil fuels for energy. We have profiled Cameroon, a country where modern bioenergy remains largely untapped due to a lack of availability of biomass data and gaps in existing policies. This study assessed the biomass resource potential in Cameroon from sustainably extracted agricultural and forest residues. We estimated that environmentally benign residues amount to 1.11 million bone dry tons per year. This has the potential to yield 0.12–0.32 billion liters of ethanol annually to displace 18–48% of the national consumption of gasoline. Alternatively, the residues could provide 0.08–0.22 billion liters of biomass to Fischer Tropsch diesel annually to offset 17–45% of diesel fuel use. For the generation of bioelectricity, the residues could supply 0.76–2.02 TW h, which is the equivalent of 15–38% of Cameroon's current electricity consumption. This could help spread electricity throughout the country, especially in farming communities where the residues are plentiful. The residues could, however, offset only 3% of the national consumption of traditional biomass (woodfuel and charcoal). Policy recommendations that promote the wider uptake of modern bioenergy applications from residues are provided. - Highlights: • Environmentally benign residues amount to 1.11×10 6 bone dry tonnes per annum. • 0.12–0.32 billion litres of bio ethanol annually to displace 18–48% national gasoline use. • 0.08–0.22 billion litres of biomass to BTL diesel per year to offset 17–45% of diesel use. • 0.76–2.02 TW h of electricity, representing 15–38% of Cameroon's consumption. • Residues could offset only 3% of national consumption of traditional biomass

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

Genetic diversity and structure of domestic cavy (Cavia porcellus populations from smallholder farms in southern Cameroon

Directory of Open Access Journals (Sweden)

Basengere Ayagirwe

2017-09-01

Full Text Available Although domestic cavies are widely used in sub-Saharan Africa as a source of meat and income, there are only a few studies of their population structure and genetic relatedness. This seminal study was designed with the main objective to assess the genetic diversity and determine the population structure of cavy populations from Cameroon to guide the development of a cavy improvement program. Sixteen microsatellite markers were used to genotype 109 individuals from five cavy populations (Wouri, Moungo and Nkongsamba in the Littoral region, and Mémé and Fako in the Southwest region of Cameroon. Twelve markers worked in the five populations with a total of 17 alleles identified, with a range of 2.9 to 4.0 alleles per locus. Observed heterozygosity (from 0.022 to 0.277 among populations was lower than expected heterozygosity (from 0.42 to 0.54. Inbreeding rates between individuals of the populations and between individuals in each population were 59.3% and 57.2%, respectively, against a moderate differentiation rate of 4.9%. All the tested loci deviated from Hardy-Weinberg equilibrium, except for locus 3. Genetic distances between populations were small (from 0.008 to 0.277, with a high rate of variability among individuals within each population (54.4%. Three distinct genetic groups were structured. This study has shown that microsatellites are useful for the genetic characterization of cavy populations in Cameroon and that the populations investigated have sufficient genetic diversity that can be used to be deployed as a basis for weight, prolificacy and disease resistance improvement. The genetic of diversity in Southern Cameroon is wide and constitute an opportunity for cavy breeding program.

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.

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

Trend in mortality from a recent measles outbreak in Cameroon: a ...

African Journals Online (AJOL)

Introduction: measles is a highly contagious viral infection with high mortality in poorly vaccinated regions. We sought to establish the trend in mortality and the factors that favoured the recent measles outbreak that occurred in Benakuma, in the North west region of Cameroon from the 21/06/2015 to 26/09/2015. Methods: we ...

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 ...

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

African Journals Online (AJOL)

user

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 ...

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

International Nuclear Information System (INIS)

Bellassen, Valentin; Gitz, Vincent

2008-01-01

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

Volcanic sulfur dioxide index and volcanic explosivity index inferred from eruptive volume of volcanoes in Jeju Island, Korea: application to volcanic hazard mitigation

Science.gov (United States)

Ko, Bokyun; Yun, Sung-Hyo

2016-04-01

Jeju Island located in the southwestern part of Korea Peninsula is a volcanic island composed of lavaflows, pyroclasts, and around 450 monogenetic volcanoes. The volcanic activity of the island commenced with phreatomagmatic eruptions under subaqueous condition ca. 1.8-2.0 Ma and lasted until ca. 1,000 year BP. For evaluating volcanic activity of the most recently erupted volcanoes with reported age, volcanic explosivity index (VEI) and volcanic sulfur dioxide index (VSI) of three volcanoes (Ilchulbong tuff cone, Songaksan tuff ring, and Biyangdo scoria cone) are inferred from their eruptive volumes. The quantity of eruptive materials such as tuff, lavaflow, scoria, and so on, is calculated using a model developed in Auckland Volcanic Field which has similar volcanic setting to the island. The eruptive volumes of them are 11,911,534 m3, 24,987,557 m3, and 9,652,025 m3, which correspond to VEI of 3, 3, and 2, respectively. According to the correlation between VEI and VSI, the average quantity of SO2 emission during an eruption with VEI of 3 is 2-8 × 103 kiloton considering that the island was formed under intraplate tectonic setting. Jeju Island was regarded as an extinct volcano, however, several studies have recently reported some volcanic eruption ages within 10,000 year BP owing to the development in age dating technique. Thus, the island is a dormant volcano potentially implying high probability to erupt again in the future. The volcanoes might have explosive eruptions (vulcanian to plinian) with the possibility that SO2 emitted by the eruption reaches stratosphere causing climate change due to backscattering incoming solar radiation, increase in cloud reflectivity, etc. Consequently, recommencement of volcanic eruption in the island is able to result in serious volcanic hazard and this study provides fundamental and important data for volcanic hazard mitigation of East Asia as well as the island. ACKNOWLEDGMENTS: This research was supported by a grant [MPSS

The Disposition of Water Supply and Demand in Cameroon: What Potential for what Standard of Living Conditions?

Directory of Open Access Journals (Sweden)

Oumar Saidou Baba

2017-04-01

Full Text Available Aim/purpose - This paper attempts to appraise the potential of water resources for Cameroon and the standard of living conditions confronting people in the country. Design/methodology/approach - A simple descriptive method of data analysis is adopted using analytical tools such as percentages, tables, and means to achieve the objectives of the inquiry. Data for the study were generated from personal observations in one hand and collected from water resources literature, on the other hand. Findings - With the help of the data gathered, the paper establishes that despite the existence of abundant water resources in Cameroon the standard of living conditions of people with respect to basic needs of survival such as drinking water, improved sanitation services, and electricity supply is far below expectation. Research implications/limitations - The main implication of the study is that in spite of the surplus volume of water resources (325.96 km3 or 95.12% of annual total water resources endowment in Cameroon, the population benefits marginally from it due to the mismanagement of resources and misplacement of priorities as obtained in most sub-Saharan African countries. One limitation of this study is that the use of limited primary data in the investigation offers no room toward establishing the extent of water resources allocation to the various users of water in the country. Originality/value/contribution - The paper suggests that the government of Cameroon should encourage the population to run community basic social services projects and subsidize the activities of such ventures in kind through technical assistance or in cash.

The Emotional World of Kinship: Children's Experiences of Fosterage in East Cameroon

Science.gov (United States)

Notermans, Catrien

2008-01-01

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

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…

Human Capital Accumulation of Children in Cameroon: Does Disability Really Matter?

Science.gov (United States)

Simo Fotso, Arlette; Solaz, Anne; Diene, Mbaye; Tsafack Nanfosso, Roger

2018-01-01

Although most of the world's disabled people live in developing countries, little is known about the consequences of disability in this part of the world. Using the DHS-MICS 2011 data of Cameroon, this paper contributes to the literature by providing new robust estimates of the effect of child disability on education in a developing country…

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.

The emotional world of kinship: Children’s experiences of fosterage in East Cameroon

NARCIS (Netherlands)

Notermans, C.D.

2008-01-01

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

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

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

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

Journal of the Cameroon Academy of Sciences - Vol 4, No 2 (2004)

African Journals Online (AJOL)

Foraging and pollination behaviour of the African Honey bee (Apis mellifera adansonii) on Callistemon rigidus flowers in Ngaoundere (Cameroon) · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. F-N Tchuenguem Fohouo, J Messi, D Brüchner, B Bouba, G Mbofung, ...

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

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Kaktchan, Pierre Marie

2015-08-01

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

"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

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

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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

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

KAUST Repository

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

2016-01-01

Mangroves are critically threatened by human activities, despite the important ecosystem functions and services they provide. Mangroves in Cameroon represent no exception to the worldwide trend of mangrove destruction, especially around Douala

Quelques exemples camerounais de liaison possible entre phénomênes géologiques et végétation

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R. Latouzey

1983-11-01

Full Text Available SOME CAMEROON EXAMPLES OF A POSSIBLE CONNECTION BETWEEN GEOLOGICALPHENOMENA AND VEGETATION The paper includes the following: a morphological, ecological and geographical description of the monophytic populations (unique in humid African forests of Gilbertiodendron dewevrei  (Caesalpiniaceae in south-east Cameroon; probable relic character of these populations; comparison with other gregarious species in the Caesalpiniaceae and Sapotaceae; hypothesis of the reduction of hydrostatic levels; — the same hypothesis related to the deep forested valleys of the Sudano-Zambezi plateau of Adamaoua in the centre of Cameroon and —  a study of a sandstone ‘inselberg,’ overhanging the dense humid evergreen forest of south-west Cameroon, with compound vegetation (a type of ‘miombo’ but including maritime littoral plants as well as endemic elements; hypothesis of recent epirogenic movements, of tectonic movements, of volcanic effects (Mont Cameroun.

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.

Implementing a Fee-for-Service Cervical Cancer Screening and Treatment Program in Cameroon: Challenges and Opportunities.

Science.gov (United States)

DeGregorio, Geneva; Manga, Simon; Kiyang, Edith; Manjuh, Florence; Bradford, Leslie; Cholli, Preetam; Wamai, Richard; Ogembo, Rebecca; Sando, Zacharie; Liu, Yuxin; Sheldon, Lisa Kennedy; Nulah, Kathleen; Welty, Thomas; Welty, Edith; Ogembo, Javier Gordon

2017-07-01

Cervical cancer screening is one of the most effective cancer prevention strategies, but most women in Africa have never been screened. In 2007, the Cameroon Baptist Convention Health Services, a large faith-based health care system in Cameroon, initiated the Women's Health Program (WHP) to address this disparity. The WHP provides fee-for-service cervical cancer screening using visual inspection with acetic acid enhanced by digital cervicography (VIA-DC), prioritizing care for women living with HIV/AIDS. They also provide clinical breast examination, family planning (FP) services, and treatment for reproductive tract infection (RTI). Here, we document the strengths and challenges of the WHP screening program and the unique aspects of the WHP model, including a fee-for-service payment system and the provision of other women's health services. We retrospectively reviewed WHP medical records from women who presented for cervical cancer screening from 2007-2014. In 8 years, WHP nurses screened 44,979 women for cervical cancer. The number of women screened increased nearly every year. The WHP is sustained primarily on fees-for-service, with external funding totaling about $20,000 annually. In 2014, of 12,191 women screened for cervical cancer, 99% received clinical breast exams, 19% received FP services, and 4.7% received treatment for RTIs. We document successes, challenges, solutions implemented, and recommendations for optimizing this screening model. The WHP's experience using a fee-for-service model for cervical cancer screening demonstrates that in Cameroon VIA-DC is acceptable, feasible, and scalable and can be nearly self-sustaining. Integrating other women's health services enabled women to address additional health care needs. The Cameroon Baptist Convention Health Services Women's Health Program successfully implemented a nurse-led, fee-for-service cervical cancer screening program using visual inspection with acetic acid-enhanced by digital cervicography in

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

NARCIS (Netherlands)

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

2013-01-01

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

Alcohol use and extramarital sex among men in Cameroon

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Wiysonge Charles

2007-08-01

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

Fathers, Families, & Child Well-Being in Cameroon: A Review of the Literature.

Science.gov (United States)

Nsamenang, A. Bame

This review discusses fatherhood in Cameroon in the context of anthropological, sociological, and psychological literature. With a focus on the family, the review examines the image and role of the father, the division of labor by gender, and the changing value of the Cameroonian father. The review notes that Cameroonian culture assigns the bulk…

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.

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.

Gender and plantation labour in Africa : the story of tea pluckers' struggles in Cameroon

NARCIS (Netherlands)

Konings, P.J.J.

2012-01-01

This book explores the relationship between plantation labour and gender in Africa, particularly Cameroon. It demonstrates that the introduction of plantation labour during colonial rule has had significant consequences for gender roles and relations within and beyond the capitalist labour process.

[Epidemiologic and clinical study of paragonimosis in Cameroon. Results of niclofolan treatment].

Science.gov (United States)

Ripert, C; Carrie, J; Ambroise-Thomas, P; Baecher, R; Kum, N P; Same-Ekobo, A

1981-01-01

Paragonimiasis does not occur only in the South West Province of Cameroon. Four foci exist in the country. They are the well known focus in the Mount Kupe area, the Mbam focus, the Nyong focus and the Ntem focus. All of them are located in the rainforest within the distribution area of Potadoma. This disease, characterized by the presence of eggs in sputum and feces, has often been confused with tuberculosis. In the villages where paragonimiasis is diagnosed by means of parasitological techniques circulating antibodies, revealed with a P. westermani antigen (ELISA), are often found in blood specimens taken from inhabitants. Teen agers suffer the most from the disease and females more often than males. Women and children are traditionally concerned with crabs fishing and they eat them after partly raw. Crabs of the genus Sudanautes contain the infective metacercariae. Paragonimiasis is enzootic and the civet cat V. civetta seems to be the main natural definitive host in Cameroon. Niclofolan given orally in a single dose of 2 mg/kg body weight showed a 100% cure rate. Side reactions are mild and transient.

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.

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

Science.gov (United States)

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

2015-01-01

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

Research evidence and policy: qualitative study in selected provinces in South Africa and Cameroon.

Science.gov (United States)

Naude, Celeste E; Zani, Babalwa; Ongolo-Zogo, Pierre; Wiysonge, Charles S; Dudley, Lillian; Kredo, Tamara; Garner, Paul; Young, Taryn

2015-09-03

The translation of research into policy and practice is enhanced by policymakers who can recognise and articulate their information needs and researchers that understand the policymakers' environment. As researchers, we sought to understand the policymaking process and how research evidence may contribute in South Africa and Cameroon. We conducted qualitative in-depth interviews in South Africa and focus group discussions in Cameroon with purposively sampled subnational (provincial and regional) government health programme managers. Audio recorded interviews were transcribed, thematically coded and analysed. Participants in both countries described the complex, often lengthy nature of policymaking processes, which often include back-and-forth consultations with many diverse stakeholder groups. These processes may be influenced by political structures, relationships between national and subnational levels, funding and international stakeholder agendas. Research is not a main driver of policy, but rather current contextual realities, costs, logistics and people (clinicians, NGOs, funders) influence the policy, and research plays a part. Research evidence is frequently perceived as unavailable, inaccessible, ill-timed or not applicable. The reliability of research on the internet was questioned. Evidence-informed health decision-making (EIDM) is regarded as necessary in South Africa but is less well understood in Cameroon. Insufficient time and capacity were hindrances to EIDM in both countries. Good relationships between researchers and policymakers may facilitate EIDM. Researchers should have a good understanding of the policymaking environment if they want to influence it. Greater interaction between policymakers and researchers is perceived as beneficial when formulating research and policy questions as it raises researchers' awareness of implementation challenges and enables the design of tailored and focused strategies to respond to policymakers' needs

The Volcanism Ontology (VO): a model of the volcanic system

Science.gov (United States)

Myer, J.; Babaie, H. A.

2017-12-01

We have modeled a part of the complex material and process entities and properties of the volcanic system in the Volcanism Ontology (VO) applying several top-level ontologies such as Basic Formal Ontology (BFO), SWEET, and Ontology of Physics for Biology (OPB) within a single framework. The continuant concepts in BFO describe features with instances that persist as wholes through time and have qualities (attributes) that may change (e.g., state, composition, and location). In VO, the continuants include lava, volcanic rock, and volcano. The occurrent concepts in BFO include processes, their temporal boundaries, and the spatio-temporal regions within which they occur. In VO, these include eruption (process), the onset of pyroclastic flow (temporal boundary), and the space and time span of the crystallization of lava in a lava tube (spatio-temporal region). These processes can be of physical (e.g., debris flow, crystallization, injection), atmospheric (e.g., vapor emission, ash particles blocking solar radiation), hydrological (e.g., diffusion of water vapor, hot spring), thermal (e.g., cooling of lava) and other types. The properties (predicates) relate continuants to other continuants, occurrents to continuants, and occurrents to occurrents. The ontology also models other concepts such as laboratory and field procedures by volcanologists, sampling by sensors, and the type of instruments applied in monitoring volcanic activity. When deployed on the web, VO will be used to explicitly and formally annotate data and information collected by volcanologists based on domain knowledge. This will enable the integration of global volcanic data and improve the interoperability of software that deal with such data.

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

2018-01-01

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 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. PMID:29387687

Review of the evolution of insecticide resistance in main malaria vectors in Cameroon from 1990 to 2017.

Science.gov (United States)

Antonio-Nkondjio, Christophe; Sonhafouo-Chiana, N; Ngadjeu, C S; Doumbe-Belisse, P; Talipouo, A; Djamouko-Djonkam, L; Kopya, E; Bamou, R; Awono-Ambene, P; Wondji, Charles S

2017-10-10

Malaria remains a major public health threat in Cameroon and disease prevention is facing strong challenges due to the rapid expansion of insecticide resistance in vector populations. The present review presents an overview of published data on insecticide resistance in the main malaria vectors in Cameroon to assist in the elaboration of future and sustainable resistance management strategies. A systematic search on mosquito susceptibility to insecticides and insecticide resistance in malaria vectors in Cameroon was conducted using online bibliographic databases including PubMed, Google and Google Scholar. From each peer-reviewed paper, information on the year of the study, mosquito species, susceptibility levels, location, insecticides, data source and resistance mechanisms were extracted and inserted in a Microsoft Excel datasheet. The data collected were then analysed for assessing insecticide resistance evolution. Thirty-three scientific publications were selected for the analysis. The rapid evolution of insecticide resistance across the country was reported from 2000 onward. Insecticide resistance was highly prevalent in both An. gambiae (s.l.) and An. funestus. DDT, permethrin, deltamethrin and bendiocarb appeared as the most affected compounds by resistance. From 2000 to 2017 a steady increase in the prevalence of kdr allele frequency was noted in almost all sites in An. gambiae (s.l.), with the L1014F kdr allele being the most prevalent. Several detoxification genes (particularly P450 monooxygenase) were associated with DDT, pyrethroids and bendiocarb resistance. In An. funestus, resistance to DDT and pyrethroids was mainly attributed to the 119F-GSTe2 metabolic resistance marker and over-expression of P450 genes whereas the 296S-RDL mutation was detected in dieldrin-resistant An. funestus. The review provides an update of insecticide resistance status in malaria vector populations in Cameroon and stresses the need for further actions to reinforce malaria

Volcanic signals in oceans

KAUST Repository

Stenchikov, Georgiy L.; Delworth, Thomas L.; Ramaswamy, V.; Stouffer, Ronald J.; Wittenberg, Andrew; Zeng, Fanrong

2009-01-01

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

[Ocular traumatism in children at Laquintinie Hospital, Douala (Cameroon)].

Science.gov (United States)

Bella-Hiag, A L; Mvogo, C E

2000-01-01

Pediatric ophthalmology is poorly developed in Cameroon. However, efforts are being made to collect data essential for the development of national strategies to combat blindness. We relate our experience, within this framework, at a large public hospital in Cameroon. We carried out a retrospective study covering the period from June 1993 to May 1998, studying the medical files of children under the age of 15 years with ocular traumatism. Data were collected from 144 files. The frequency of ocular/orbital injury was 7.8% and was the third most common condition, after ametropia and kerato-conjunctivitis, in this population. The mean age of the children was 7 years and 3 months and more boys (64%) than girls were affected. Ocular lesions were due to contusion in 83.3% of cases. The principal causes of the trauma were children's games (40.2%), and punishment by parents or teachers (23.7%). The ocular lesions were similar to those described in previous studies. Infection was rare, because the interval from trauma to consultation was very short. The functional prognosis was severe, with 24.3% of patients having final vision less than 1/10. We recommend that children should be informed about the dangers of violent games and that parents and teachers should be made aware of the dangers associated with brutality towards children. Finally, ophthalmologists should ensure that the injured eye is treated rapidly and carefully so as to minimize functional sequelae.

Marketing Cameroon as a Cultural Tourism Destination to Finnish Tourists

OpenAIRE

Akuri, Lucien; Landa Celestin, Ndingi

2013-01-01

Cultural tourism is already a global phenomenon and has been increasingly promoted in the forms such as heritage, arts, creative, rural and urban cultural tourism, amongst others, and their sub-sections. The marketing of these cultural tourism forms and their attractions by various tourism destinations to target markets is still complex and thus, a major challenge. The study investigates the ways in which Cameroon with very rich and diverse cultural products and attractions can be markete...

HIV-1 group O infection in Cameroon from 2006 to 2013: Prevalence, genetic diversity, evolution and public health challenges

Science.gov (United States)

Villabona-Arenas, Christian Julian; Domyeum, Jenny; Mouacha, Fatima; Butel, Christelle; Delaporte, Eric; Peeters, Martine; Mpoudi-Ngole, Eitel; Aghokeng, Avelin Fobang

2015-01-01

The human immunodeficiency virus, HIV, is characterized by a tremendously high genetic diversity, leading to the currently known circulating HIV types, groups, subtypes, and recombinant forms. HIV-1 group O is one of the most diverse forms of HIV-1 and has been so far related to Cameroon or individuals originating from Cameroon. In this study, we investigated in Cameroon, the evolution of this viral group from 2006 to 2013, in terms of prevalence, genetic diversity and public health implications. Our results confirmed the predominance of HIV-1 group M (98.5%), a very low prevalence (O was found at around 0.6% (95% confidence interval: 0.4–0.8%), indicating that the frequency of this virus in Cameroon has remained stable over the last decades. However, we found an extensive high genetic diversity within this HIV-1 group, that resulted from previous steady increase on the effective number of HIV-1 group O infections through time, and the current distribution of the circulating viral strains still does not allow classification as subtypes. The frequency of dual infections with HIV-1 group M and group O was 0.8% (95% confidence interval: 0.6–1.0%), but we found no recombinant forms in co-infected patients. Natural resistance to integrase inhibitors was not identified, although we found several mutations considered as natural polymorphisms. Our study shows that infections with HIV-1 group O can be adequately managed in countries where the virus circulates, but this complex virus still represents a challenge for diagnostics and monitoring strategies. PMID:26371064

Estrutura do pasto disponível e do resíduo pós-pastejo em pastagens de capim-cameroon e capim-marandu Pasture structure and post-grazing herbage mass in pastures of elephantgrass cv. Cameroon and palisadegrass cv. Marandu

Directory of Open Access Journals (Sweden)

Cláudia de Paula Rezende

2008-10-01

Full Text Available Avaliaram-se, em dois experimentos, as características estruturais e o teor de proteína bruta das forrageiras Pennisetum purpureum cv. Cameroon e Brachiaria brizantha cv. Marandu em pastagens submetidas a quatro taxas de lotação rotacionadas. No período das águas, as taxas de lotação impostas a ambas as pastagens foram de 3, 4, 5 e 6 novilhos/ha e, no período seco, de 2, 3, 4 e 5 novilhos/ha. Nos dois experimentos, o capim-cameroon apresentou maior massa de forragem total e massa de forragem verde, que decresceram com o aumento da desfolha imposta pelas taxas de lotação, principalmente no período seco. Nessa forrageira, o aumento da taxa de lotação comprometeu em maior intensidade a fração de matéria seca de lâmina foliar verde. No período das águas, as taxas de lotação que propiciaram maior oferta de massa seca de forragem total, forragem verde e fração de lâmina foliar foram as de 5 e 4 novilhos/ha, respectivamente, para os capins cameroon e marandu. No período seco, no entanto, os maiores valores obtidos para essas variáveis foram, respectivamente, de 4 e 3 novilhos/ha. As taxas de lotação não influenciaram o teor de proteína bruta das gramíneas, que foi maior no componente lâmina foliar verde da planta.Two experiments were carried out to evaluate structural characteristics and crude protein concentration of Pennisetum purpureum cv. Cameroon and Brachiaria brizantha cv. Marandu under four rotational stocking rates. During the rainfall period, the studied stocking rates for both pastures were 3, 4, 5, and 6 steers/ha and in the dry period the stocking rates were 2, 3, 4, and 5 steers/ha. In both experiments, elephantgrass cv. Cameroon produced greater total herbage mass and green herbage mass, which decreased with the increase in defoliation as a result of the used stocking rates, mainly during the dry period. For elephantgrass pastures, the increase in stocking rate had a greater negative effect on the green

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

‘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

Information circulation in rice production: the case of UNVDA and Ndop rice farmers, Cameroon

NARCIS (Netherlands)

Chindong, P.E.

2008-01-01

The study revealed that the dominant Agricultural extension approaches used in the rice sector in Cameroon is ToT and T&V. The methods of information circulation using these approaches are individual and group methods. The extension approaches has been criticized for its ineffectiveness especially

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

Shift of Enterovirus species among children in Cameroon--identification of a new enterovirus, EV-A119.

Science.gov (United States)

Ayukekbong, James; Kabayiza, Jean-Claude; Lindh, Magnus; Nkuo-Akenji, Theresia; Tah, Ferdinand; Bergström, Tomas; Norder, Helene

2013-09-01

Infections caused by human enteroviruses (EVs) are often asymptomatic or mild, although they may cause more severe illnesses as meningitis and acute flaccid paralysis. EVs have globally posed a threat to children, and outbreaks of aseptic meningitis and hand, foot and mouth disease are frequently reported. To identify EV strains circulating among healthy children in a small community in Limbe, Cameroon two years apart. Species and EV types were obtained by partial 5'UTR-VP4 and VP1 sequencing of RNA from stool samples collected in October 2009 and September 2011 from 150 children in Cameroon. In all, 74 children (49%) were infected with 28 different types of EV. There were 29 (54%) infected children in 2009, and 45 (47%) in 2011. There was a significant difference between detected species of EV, with 15 (47%) children infected with EV-A in 2009, and 22 (71%) with EV-B in 2011 (p=0.0001). In 2009, one child was infected by a divergent EV, which was most similar to EV-A90. Based on the complete VP1 sequence, it was shown to be a new EV designated EV-A119. The current study shows a high heterogeneity of circulating EV types among children in Limbe, Cameroon, and a previously not described shift in predominating EV species. Copyright © 2013 Elsevier B.V. All rights reserved.

Candidate constructional volcanic edifices on Mercury

OpenAIRE

Wright, J.; Rothery, D. A.; Balme, M. R.; Conway, S. J.

2018-01-01

[Introduction] Studies using MESSENGER data suggest that Mercury’s crust is predominantly a product of effusive volcanism that occurred in the first billion years following the planet’s formation. Despite this planet-wide effusive volcanism, no constructional volcanic edifices, characterized by a topographic rise, have hitherto been robustly identified on Mercury, whereas constructional volcanoes are common on other planetary bodies in the solar system with volcanic histories. Here, we descri...

Disruptive event analysis: volcanism and igneous intrusion

International Nuclear Information System (INIS)

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

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

The Weight of Health Expenditures on Household Income in Cameroon

Directory of Open Access Journals (Sweden)

Joseph Parfait OWOUNDI

2014-02-01

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

Atmospheric dust contribution to budget of U-series nuclides in weathering profiles. The Mount Cameroon volcano

Science.gov (United States)

Pelt, E.; Chabaux, F. J.; Innocent, C.; Ghaleb, B.

2009-12-01

Analysis of U-series nuclides in weathering profiles is developed today for constraining time scale of soil and weathering profile formation (e.g., Chabaux et al., 2008). These studies require the understanding of U-series nuclides sources and fractionation in weathering systems. For most of these studies the impact of aeolian inputs on U-series nuclides in soils is usually neglected. Here, we propose to discuss such an assumption, i.e., to evaluate the impact of dust deposition on U-series nuclides in soils, by working on present and paleo-soils collected on the Mount Cameroon volcano. Recent Sr, Nd, Pb isotopic analyses performed on these samples have indeed documented significant inputs of Saharan dusts in these soils (Dia et al., 2006). We have therefore analyzed 238U-234U-230Th nuclides in the same samples. Comparison of U-Th isotopic data with Sr-Nd-Pb isotopic data indicates a significant impact of the dust input on the U and Th budget of the soils, around 10% for both U and Th. Using Sr-Nd-Pb isotopic data of Saharan dusts given by Dia et al. (2006) we estimate U-Th concentrations and U-Th isotope ratios of dusts compatible with U-Th data obtained on Saharan dusts collected in Barbados (Rydell H.S. and Prospero J.M., 1972). However, the variations of U/Th ratios along the weathering profiles cannot be explained by a simple mixing scenario between material from basalt and from the defined atmospheric dust pool. A secondary uranium migration associated with chemical weathering has affected the weathering profiles. Mass balance calculation suggests that U in soils from Mount Cameroon is affected at the same order of magnitude by both chemical migration and dust accretion. Nevertheless, the Mount Cameroon is a limit case were large dust inputs from continental crust of Sahara contaminate basaltic terrain from Mount Cameroon volcano. Therefore, this study suggests that in other contexts were dust inputs are lower, or the bedrocks more concentrated in U and Th

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

Directory of Open Access Journals (Sweden)

Lynn Cockburn

2014-11-01

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.

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

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. 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. 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 (peducation toward universal coverage of malaria vector control in Cameroon.

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.

Higher Education Strategic Planning in Sub-Saharan Africa: A Case Study of Cameroon.

Science.gov (United States)

Ngwana, Terfot Augustine

This paper argues that a framework for strategic planning in universities in Sub-Saharan Africa can be developed with the background of global, regional, and institutional realities. Using the specific case of the University of Buea in Cameroon, the paper attempts to expose the global trends of polarization in knowledge production capacity as an…

Challenges to implementing Gavi's health system strengthening support in Chad and Cameroon: results from a mixed-methods evaluation.

Science.gov (United States)

Dansereau, Emily; Miangotar, Yodé; Squires, Ellen; Mimche, Honoré; El Bcheraoui, Charbel

2017-11-16

Since 2005, Gavi has provided health system strengthening (HSS) grants to address bottlenecks affecting immunization services. This study is the first to evaluate the Gavi HSS implementation process in either Cameroon or Chad, two countries with significant health system challenges and poor achievement on the child and maternal health Millennium Development Goals. We triangulated quantitative and qualitative data including financial records, document review, field visit questionnaires, and key informant interviews (KII) with representatives from the Ministries of Health, Gavi, and other partners. We conducted a Root Cause Analysis of key implementation challenges, guided by the Consolidated Framework for Implementation Research. We conducted 124 field visits and 43 KIIs in Cameroon, and 57 field visits and 39 KIIs in Chad. Cameroon's and Chad's HSS programs were characterized by delayed disbursements, significant deviations from approved expenditures, and reprogramming of funds. Nearly a year after the programs were intended to be complete, many district and facility-level activities were only partially implemented and significant funds remained unabsorbed. Root causes of these challenges included unpredictable Gavi processes and disbursements, poor communication between the countries and Gavi, insufficient country planning without adequate technical assistance, lack of country staff and leadership, and weak country systems to manage finances and promote institutional memory. Though Chad and Cameroon both critically needed support to strengthen their weak health systems, serious challenges drastically limited implementation of their Gavi HSS programs. Implementation of future HSS programs in these and similar settings can be improved by transparent and reliable procedures and communication from Gavi, proposals that account for countries' programmatic capacity and the potential for delayed disbursements, implementation practices that foster learning and adaptation

A practical approach to low protein diets for patients with chronic kidney disease in Cameroon.

Science.gov (United States)

Ashuntantang, Gloria Enow; Fouda, Hermine; Kaze, Francois Folefack; Halle, Marie-Patrice; Tabi-Arrey, Crista; Biwole-Sida, Magloire

2016-09-07

Cameroon is a low-middle income country with a rich diversity of culture and cuisine. Chronic kidney disease (CKD) is common in Cameroon and over 80 % of patients present late for care, precluding the use of therapies such as low protein diets (LPDs) that slow its progression. Moreover, the prescription of LPDs is challenging in Cameroon because dieticians are scarce, there are no renal dieticians, and people often have to fund their own healthcare. The few nephrologists that provide care for CKD patients have limited expertise in LPD design. Therefore, only moderate LPDs of 0.6 g protein per kg bodyweight per day, or relatively mild LPDs of 0.7-0.8 g protein per kg bodyweight per day are prescribed. The moderate LPD is prescribed to patients with stage 3 or 4 CKD with non-nephrotic proteinuria, no evidence of malnutrition and no interrcurrent acute illnesses. The mild LPD is prescribed to patients with stage 3 or 4 CKD with nephrotic proteinuria, non-symptomatic stage 5 CKD patients or stage 5 CKD patients on non-dialysis treatment. In the absence of local sources of amino and keto acid supplements, traditional mixed LPDs are used. For patients with limited and sporadic access to animal proteins, the prescribed LPDs do not restrict vegetable proteins, but limit intake of animal proteins (when available) to 70 % of total daily protein intake. For those with better access to animal proteins, the prescribed LPDs limit intake of animal proteins to 50-70 % of total daily protein intake, depending on their meal plan. Images of 100 g portions of meat, fish and readily available composite meals serve as visual guides of quantities for patients. Nutritional status is assessed before LPD prescription and during follow up using a subjective global assessment and serum albumin. In conclusion, LPDs are underutilised and challenging to prescribe in Cameroon because of weakness in the health system, the rarity of dieticians, a wide diversity of dietary habits, the limited

Language Models and the Teaching of English Language to Secondary School Students in Cameroon

Science.gov (United States)

Ntongieh, Njwe Amah Eyovi

2016-01-01

This paper investigates Language models with an emphasis on an appraisal of the Competence Based Language Teaching Model (CBLT) employed in the teaching and learning of English language in Cameroon. Research endeavours at various levels combined with cumulative deficiencies experienced over the years have propelled educational policy makers to…

Using Volcanic Lightning Measurements to Discern Variations in Explosive Volcanic Activity

Science.gov (United States)

Behnke, S. A.; Thomas, R. J.; McNutt, S. R.; Edens, H. E.; Krehbiel, P. R.; Rison, W.

2013-12-01

VHF observations of volcanic lightning have been made during the recent eruptions of Augustine Volcano (2006, Alaska, USA), Redoubt Volcano (2009, Alaska, USA), and Eyjafjallajökull (2010, Iceland). These show that electrical activity occurs both on small scales at the vent of the volcano, concurrent with an eruptive event and on large scales throughout the eruption column during and subsequent to an eruptive event. The small-scale discharges at the vent of the volcano are often referred to as 'vent discharges' and are on the order of 10-100 meters in length and occur at rates on the order of 1000 per second. The high rate of vent discharges produces a distinct VHF signature that is sometimes referred to as 'continuous RF' radiation. VHF radiation from vent discharges has been observed at sensors placed as far as 100 km from the volcano. VHF and infrasound measurements have shown that vent discharges occur simultaneously with the onset of eruption, making their detection an unambiguous indicator of explosive volcanic activity. The fact that vent discharges are observed concurrent with explosive volcanic activity indicates that volcanic ejecta are charged upon eruption. VHF observations have shown that the intensity of vent discharges varies between eruptive events, suggesting that fluctuations in eruptive processes affect the electrification processes giving rise to vent discharges. These fluctuations may be variations in eruptive vigor or variations in the type of eruption; however, the data obtained so far do not show a clear relationship between eruption parameters and the intensity or occurrence of vent discharges. Further study is needed to clarify the link between vent discharges and eruptive behavior, such as more detailed lightning observations concurrent with tephra measurements and other measures of eruptive strength. Observations of vent discharges, and volcanic lightning observations in general, are a valuable tool for volcano monitoring, providing a

Serotype Diversity of Foot-and-Mouth-Disease Virus in Livestock without History of Vaccination in the Far North Region of Cameroon.

Science.gov (United States)

Ludi, A; Ahmed, Z; Pomeroy, L W; Pauszek, S J; Smoliga, G R; Moritz, M; Dickmu, S; Abdoulkadiri, S; Arzt, J; Garabed, R; Rodriguez, L L

2016-02-01

Little information is available about the natural cycle of foot-and-mouth disease (FMD) in the absence of control measures such as vaccination. Cameroon presents a unique opportunity for epidemiological studies because FMD vaccination is not practiced. We carried out a prospective study including serological, antigenic and genetic aspects of FMD virus (FMDV) infections among different livestock production systems in the Far North of Cameroon to gain insight into the natural ecology of the virus. We found serological evidence of FMDV infection in over 75% of the animals sampled with no significant differences of prevalence observed among the sampled groups (i.e. market, sedentary, transboundary trade and mobile). We also found antibodies reactive to five of the seven FMDV serotypes (A, O, SAT1, SAT2 and SAT3) among the animals sampled. Finally, we were able to genetically characterize viruses obtained from clinical and subclinical FMD infections in Cameroon. Serotype O viruses grouped into two topotypes (West and East Africa). SAT2 viruses grouped with viruses from Central and Northern Africa, notably within the sublineage causing the large epidemic in Northern Africa in 2012, suggesting a common origin for these viruses. This research will guide future interventions for the control of FMD such as improved diagnostics, guidance for vaccine formulation and epidemiological understanding in support of the progressive control of FMD in Cameroon. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

Recurrence models of volcanic events: Applications to volcanic risk assessment

International Nuclear Information System (INIS)

Crowe, B.M.; Picard, R.; Valentine, G.; Perry, F.V.

1992-01-01

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

Volcanic Plume Measurements with UAV (Invited)

Science.gov (United States)

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

2013-12-01

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

Marine pollution in Cameroon (Gulf of Guinea): State and remedies for successful control and monitoring

International Nuclear Information System (INIS)

Folack, J.

1999-01-01

This paper analyses the various research results obtained over several years in Cameroon on coastal and marine pollution, especially pollution by solid wastes, industrial and domestic effluents, hydrocarbons (tar balls), heavy metals and pesticides. Values in the order of 175,531 and 194,685 tons have been estimated for annual pollution loads in terms of BOD and suspended matter respectively. With respect to BOD, the most polluting industries are petroleum refineries, food processing and chemical industries which respectively represent 38, 36 and 10% of the total annual BOD. Measurement of tar balls on various Cameroonian beaches shows values as high as 42.40 g/m 2 of beach, while the concentration of heavy metals encountered in shrimps and fish consumed in Cameroon shows a very wide range of values. Most of these values are similar to those obtained within the region, and some are alarming in their magnitude

AfricaArray: aims, achievements and future activities

CSIR Research Space (South Africa)

Durrheim, RJ

2009-09-01

Full Text Available data that can augment groundwater, oil, gas, and mineral exploration, and help the forecasting of natural hazards such as earthquakes and volcanic eruptions. Network capabilities are initially focused on seismic sensors, but expansions are planned... also form part of the Indian Ocean Tsunami Early Warning System. Earthquakes are often precursors of volcanic eruptions, enabling timely evacuation. The Nyiragongo volcano (DRC) and Mount Cameroon are being monitored. The most recent major eruption...

[Plants and their use by the people of Northern Cameroon: selection and use in the nineteenth and twentieth centuries].

Science.gov (United States)

Gormo, Jean; Nizesete, Bienvenu Denis

2013-06-01

The functional versatility of plants can be seen in their numerous uses by the people of Northern Cameroon. They have implemented local know-how which has allowed them to effectively exploit their botanical environment. The disappearance of valuable species has forced them to develop other strategies, with a new era marked by the consumption of manufactured products. This article summarizes the principal uses of plants by the people of Northern Cameroon, evaluates their strategies for extracting value from grasses and woods, and questions the validity of the measures currently in place to preserve the botanical heritage at risk due to the actions of man and nature.

The influence of rural-urban migration on migrant's fertility behavior in Cameroon.

Science.gov (United States)

Lee, B S

1992-01-01

Preliminary analysis of Cameroon fertility data suggests that rural stayers do not have a significantly higher fertility than rural-urban migrants in contrast to hypotheses suggested in the literature. Bongaarts and Caldwell both suggest that modernization plays a role in African fertility and migration patterns by increasing exposure to childbearing. Supply constraints are changed by higher levels of education, short duration of postpartum abstinence, less prevalence of polygamy, and more stable marriages. The influence of relatives may be weaker and the fear of losing a husband greater, which influence earlier returns to sexual relations. Because the levels of fertility of stayers and movers may be equal does not suggest that movers do not adapt fertility to urban norms. Analysis was conducted with d ata from the 1978 Cameroon World Fertility Survey on 8219 women aged 15-54 years for rural nonmigrants, rural-rural migrants, and rural-urban migrants. Rural-urban migrants were found to be better educated, have fewer cases of infertility, and have more stable first marriages. Descriptive statistics are provided for migrants and nonmigrants. Cross classification analysis shows that fertility is not lower for women with higher education, even when migration status is controlled for. Multivariate regression results in an autoregressive model in a first difference form indicated that the fertility rate of rural-urban migrant women was significantly higher than that of rural staryers during the period of 5-9 years after migration. The urban effect acts to reduce migrants' fertility by about .13 births. Comparisons are made with Mexican and Korean migration behavior, which reflect decreased fertility after migration of 1.5 births and 2.6 births, respectively. The suggestion is that the fertility-increasing effect of supply conditions in Cameroon is significantly offset by the fertility-depressing adaptation effect of migration to urban areas. It is expected that

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…

Conceptual model of volcanism and volcanic hazards of the region of Ararat valley, Armenia

Science.gov (United States)

Meliksetian, Khachatur; Connor, Charles; Savov, Ivan; Connor, Laura; Navasardyan, Gevorg; Manucharyan, Davit; Ghukasyan, Yura; Gevorgyan, Hripsime

2015-04-01

Armenia and the adjacent volcanically active regions in Iran, Turkey and Georgia are located in the collision zone between the Arabian and Eurasian lithospheric plates. The majority of studies of regional collision related volcanism use the model proposed by Keskin, (2003) where volcanism is driven by Neo-Tethyan slab break-off. In Armenia, >500 Quaternary-Holocene volcanoes from the Gegham, Vardenis and Syunik volcanic fields are hosted within pull-apart structures formed by active faults and their segments (Karakhanyan et al., 2002), while tectonic position of the large in volume basalt-dacite Aragats volcano and periphery volcanic plateaus is different and its position away from major fault lines necessitates more complex volcano-tectonic setup. Our detailed volcanological, petrological and geochemical studies provide insight into the nature of such volcanic activity in the region of Ararat Valley. Most magmas, such as those erupted in Armenia are volatile-poor and erupt fairly hot. Here we report newly discovered tephra sequences in Ararat valley, that were erupted from historically active Ararat stratovolcano and provide evidence for explosive eruption of young, mid K2O calc-alkaline and volatile-rich (>4.6 wt% H2O; amph-bearing) magmas. Such young eruptions, in addition to the ignimbrite and lava flow hazards from Gegham and Aragats, present a threat to the >1.4 million people (~ ½ of the population of Armenia). We will report numerical simulations of potential volcanic hazards for the region of Ararat valley near Yerevan that will include including tephra fallout, lava flows and opening of new vents. Connor et al. (2012) J. Applied Volcanology 1:3, 1-19; Karakhanian et al. (2002), JVGR, 113, 319-344; Keskin, M. (2003) Geophys. Res. Lett. 30, 24, 8046.

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

Directory of Open Access Journals (Sweden)

Asonganyi Etienne DN

2005-06-01

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

Lead exposure from aluminum cookware in Cameroon

International Nuclear Information System (INIS)

Weidenhamer, Jeffrey D.; Kobunski, Peter A.; Kuepouo, Gilbert; Corbin, Rebecca W.; Gottesfeld, Perry

2014-01-01

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. �

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. �

Closer look at lunar volcanism

International Nuclear Information System (INIS)

Vaniman, D.T.; Heiken, G.; Taylor, G.J.

1984-01-01

Although the American Apollo and Soviet Luna missions concentrated on mare basalt samples, major questions remain about lunar volcanism. Lunar field work will be indispensable for resolving the scientific questions about ages, compositions, and eruption processes of lunar volcanism. From a utilitarian standpoint, a better knowledge of lunar volcanism will also yield profitable returns in lunar base construction (e.g., exploitation of rille or lava-tube structures) and in access to materials such as volatile elements, pure glass, or ilmenite for lunar industry

Volcanic alert system (VAS) developed during the 2011-2014 El Hierro (Canary Islands) volcanic process

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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.

Lidar sounding of volcanic plumes

Science.gov (United States)

Fiorani, Luca; Aiuppa, Alessandro; Angelini, Federico; Borelli, Rodolfo; Del Franco, Mario; Murra, Daniele; Pistilli, Marco; Puiu, Adriana; Santoro, Simone

2013-10-01

Accurate knowledge of gas composition in volcanic plumes has high scientific and societal value. On the one hand, it gives information on the geophysical processes taking place inside volcanos; on the other hand, it provides alert on possible eruptions. For this reasons, it has been suggested to monitor volcanic plumes by lidar. In particular, one of the aims of the FP7 ERC project BRIDGE is the measurement of CO2 concentration in volcanic gases by differential absorption lidar. This is a very challenging task due to the harsh environment, the narrowness and weakness of the CO2 absorption lines and the difficulty to procure a suitable laser source. This paper, after a review on remote sensing of volcanic plumes, reports on the current progress of the lidar system.

Gas measurements from the Costa Rica-Nicaragua volcanic segment suggest possible along-arc variations in volcanic gas chemistry

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Aiuppa, A.; Robidoux, P.; Tamburello, G.; Conde, V.; Galle, B.; Avard, G.; Bagnato, E.; De Moor, J. M.; Martínez, M.; Muñóz, A.

2014-12-01

Obtaining accurate estimates of the CO2 output from arc volcanism requires a precise understanding of the potential along-arc variations in volcanic gas chemistry, and ultimately of the magmatic gas signature of each individual arc segment. In an attempt to more fully constrain the magmatic gas signature of the Central America Volcanic Arc (CAVA), we present here the results of a volcanic gas survey performed during March and April 2013 at five degassing volcanoes within the Costa Rica-Nicaragua volcanic segment (CNVS). Observations of the volcanic gas plume made with a multicomponent gas analyzer system (Multi-GAS) have allowed characterization of the CO2/SO2-ratio signature of the plumes at Poás (0.30±0.06, mean ± SD), Rincón de la Vieja (27.0±15.3), and Turrialba (2.2±0.8) in Costa Rica, and at Telica (3.0±0.9) and San Cristóbal (4.2±1.3) in Nicaragua (all ratios on molar basis). By scaling these plume compositions to simultaneously measured SO2 fluxes, we estimate that the CO2 outputs at CNVS volcanoes range from low (25.5±11.0 tons/day at Poás) to moderate (918 to 1270 tons/day at Turrialba). These results add a new information to the still fragmentary volcanic CO2 output data set, and allow estimating the total CO2 output from the CNVS at 2835±1364 tons/day. Our novel results, with previously available information about gas emissions in Central America, are suggestive of distinct volcanic gas CO2/ST (= SO2 + H2S)-ratio signature for magmatic volatiles in Nicaragua (∼3) relative to Costa Rica (∼0.5-1.0). We also provide additional evidence for the earlier theory relating the CO2-richer signature of Nicaragua volcanism to increased contributions from slab-derived fluids, relative to more-MORB-like volcanism in Costa Rica. The sizeable along-arc variations in magmatic gas chemistry that the present study has suggested indicate that additional gas observations are urgently needed to more-precisely confine the volcanic CO2 from the CAVA, and from

Structural control of monogenetic volcanism in the Garrotxa volcanic field (Northeastern Spain) from gravity and self-potential measurements

Science.gov (United States)

Barde-Cabusson, S.; Gottsmann, J.; Martí, J.; Bolós, X.; Camacho, A. G.; Geyer, A.; Planagumà, Ll.; Ronchin, E.; Sánchez, A.

2014-01-01

We report new geophysical observations on the distribution of subsurface structures associated with monogenetic volcanism in the Garrotxa volcanic field (Northern Spain). As part of the Catalan Volcanic Zone, this Quaternary volcanic field is associated with the European rifts system. It contains the most recent and best preserved volcanic edifices of the Catalan Volcanic Zone with 38 monogenetic volcanoes identified in the Garrotxa Natural Park. We conducted new gravimetric and self-potential surveys to enhance our understanding of the relationship between the local geology and the spatial distribution of the monogenetic volcanoes. The main finding of this study is that the central part of the volcanic field is dominated by a broad negative Bouguer anomaly of around -0.5 mGal, within which a series of gravity minima are found with amplitudes of up to -2.3 mGal. Inverse modelling of the Bouguer data suggests that surficial low-density material dominates the volcanic field, most likely associated with effusive and explosive surface deposits. In contrast, an arcuate cluster of gravity minima to the NW of the Croscat volcano, the youngest volcano of this zone, is modelled by vertically extended low-density bodies, which we interpret as a complex ensemble of fault damage zones and the roots of young scoria cones. A ground-water infiltration zone identified by a self-potential anomaly is associated with a steep horizontal Bouguer gravity gradient and interpreted as a fault zone and/or magmatic fissure, which fed the most recent volcanic activity in the Garrotxa. Gravimetric and self-potential data are well correlated and indicate a control on the locations of scoria cones by NNE-SSW and NNW-SSE striking tectonic features, which intersect the main structural boundaries of the study area to the north and south. Our interpretation of the data is that faults facilitated magma ascent to the surface. Our findings have major implications for understanding the relationship

New species of Auritella (Inocybaceae) from Cameroon, with a worldwide key to the known species.

Science.gov (United States)

Matheny, P Brandon; Henkel, Terry W; Séné, Olivier; Korotkin, Hailee B; Dentinger, Bryn T M; Aime, M Catherine

2017-12-01

Two new species in the genus Auritella ( Inocybaceae ) are described as new from tropical rainforest in Cameroon. Descriptions, photographs, line drawings, and a worldwide taxonomic key to the described species of Auritella are presented. Phylogenetic analysis of 28S rDNA and rpb2 nucleotide sequence data suggests at least five phylogenetic species that can be ascribed to Auritella occur in the region comprising Cameroon and Gabon and constitute a strongly supported monophyletic subgroup within the genus. Phylogenetic analysis of ITS data supports the conspecificity of numerous collections attributed to the two new species as well as the monophyly of Australian species of Auritella . This work raises the known number of described species of Auritella to thirteen worldwide, four of which occur in tropical Africa, one in tropical India, and eight in temperate and tropical regions of Australia. This is the first study to confirm an ectomycorrhizal status of Auritella using molecular data.

Factors Associated with Fatal Outcomes Following Cholera-Like Syndrome in Far North Region of Cameroon: A Community-Based Survey.

Science.gov (United States)

Djouma, Fabrice N; Ateudjieu, Jerome; Ram, Malathi; Debes, Amanda K; Sack, David A

2016-12-07

This study demonstrates that most cholera deaths in this region of Cameroon occur out of hospital. This is a region which is prone to cholera, and interventions are needed to improve access to emergency medical care, especially during cholera outbreaks. Cameroon has experienced 14 cholera epidemics during the last 20 years, and these have had high case fatality rates. This study attempted to assess the effect of delays in seeking care and the locations of care as possible risk factors for cholera mortality. The study used data from a community-based survey regarding the circumstances of 97 fatal cases and 197 control (nonfatal) cases following a cholera-like syndrome in villages with cholera-like diseases during cholera outbreaks in Cameroon during 2009-2011. Deaths occurred in one of four environments: the community, in a temporary community treatment center (TCTC), in transit to a treatment center, or in a hospital (39%, 32%, 5%, and 24%, respectively). Using a case-control analysis, factors associated with deaths included the nonuse of a cholera treatment center, receiving health care in a TCTC instead of a hospital, and greater than 4 hours delay between the onset of symptoms and the decision to go to a treatment center (odds ratios of 17.1 [confidence interval (CI): 7.0-41.8], 2.5 [CI: 1.2-5.0], and 2.2 [CI: 1.0-4.6], respectively). During cholera epidemics, a higher proportion of deaths are still occurring in communities. The nonuse and delays in deciding to go a treatment center, and treatment at TCTC rather than a hospital were risk factors for death among patients with cholera-like syndrome in Cameroon. Informing people on community management of cholera-like syndrome and improving care in all health facilities are needed to reduce deaths during cholera epidemics. © The American Society of Tropical Medicine and Hygiene.

Volcanic Hazards in Site Evaluation for Nuclear Installations

Energy Technology Data Exchange (ETDEWEB)

NONE

2012-10-15

This publication provides comprehensive and updated guidance for site evaluation in relation to volcanic hazards. It includes recommendations on assessing the volcanic hazards at a nuclear installation site, in order to identify and characterize, in a comprehensive manner, all potentially hazardous phenomena that may be associated with future volcanic events. It describes how some of these volcanic phenomena may affect the acceptability of the selected site, resulting in exclusion of a site or determining the corresponding design basis parameters for the installation. This Safety Guide is applicable to both existing and new sites, and a graded approach is recommended to cater for all types of nuclear installations. Contents: 1. Introduction; 2. Overview of volcanic hazard assessment; 3. General recommendations; 4. Necessary information and investigations (database); 5. Screening of volcanic hazards; 6. Site specific volcanic hazard assessment; 7. Nuclear installations other than nuclear power plants; 8. Monitoring and preparation for response; 9. Management system for volcanic hazard assessment; Annex I: Volcanic hazard scenarios; Annex II: Worldwide sources of information.

Volcanic ash in ancient Maya ceramics of the limestone lowlands: implications for prehistoric volcanic activity in the Guatemala highlands

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Ford, Anabel; Rose, William I.

1995-07-01

In the spirit of collaborative research, Glicken and Ford embarked on the problem of identifying the source of volcanic ash used as temper in prehistoric Maya ceramics. Verification of the presence of glass shards and associated volcanic mineralogy in thin sections of Maya ceramics was straightforward and pointed to the Guatemala Highland volcanic chain. Considering seasonal wind rose patterns, target volcanoes include those from the area west of and including Guatemala City. Joint field research conducted in 1983 by Glicken and Ford in the limestone lowlands of Belize and neighboring Guatemala, 300 km north of the volcanic zone and 150 km from the nearest identified ash deposits, was unsuccessful in discovering local volcanic ash deposits. The abundance of the ash in common Maya ceramic vessels coupled with the difficulties of long-distance procurement without draft animals lead Glicken to suggest that ashfall into the lowlands would most parsimoniously explain prehistoric procurement; it literally dropped into their hands. A major archaeological problem with this explanation is that the use of volcanic ash occurring over several centuries of the Late Classic Period (ca. 600-900 AD). To accept the ashfall hypothesis for ancient Maya volcanic ash procurement, one would have to demonstrate a long span of consistent volcanic activity in the Guatemala Highlands for the last half of the first millennium AD. Should this be documented through careful petrographic, microprobe and tephrachronological studies, a number of related archaeological phenomena would be explained. In addition, the proposed model of volcanic activity has implications for understanding volcanism and potential volcanic hazards in Central America over a significantly longer time span than the historic period. These avenues are explored and a call for further collaborative research of this interdisciplinary problem is extended in this paper.

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.

Geophysical expression of caldera related volcanism, structures and mineralization in the McDermitt volcanic field

Science.gov (United States)

Rytuba, J. J.; Blakely, R. J.; Moring, B.; Miller, R.

2013-12-01

The High Rock, Lake Owyhee, and McDermitt volcanic fields, consisting of regionally extensive ash flow tuffs and associated calderas, developed in NW Nevada and SE Oregon following eruption of the ca. 16.7 Ma Steens flood basalt. The first ash flow, the Tuff of Oregon Canyon, erupted from the McDermitt volcanic field at 16.5Ma. It is chemically zoned from peralkaline rhyolite to dacite with trace element ratios that distinguish it from other ash flow tuffs. The source caldera, based on tuff distribution, thickness, and size of lithic fragments, is in the area in which the McDermitt caldera (16.3 Ma) subsequently formed. Gravity and magnetic anomalies are associated with some but not all of the calderas. The White Horse caldera (15.6 Ma), the youngest caldera in the McDermitt volcanic field has the best geophysical expression, with both aeromagnetic and gravity lows coinciding with the caldera. Detailed aeromagnetic and gravity surveys of the McDermitt caldera, combined with geology and radiometric surveys, provides insight into the complexities of caldera collapse, resurgence, post collapse volcanism, and hydrothermal mineralization. The McDermitt caldera is among the most mineralized calderas in the world, whereas other calderas in these three Mid Miocene volcanic fields do not contain important hydrothermal ore deposits, despite having similar age and chemistry. The McDermitt caldera is host to Hg, U, and Li deposits and potentially significant resources of Ga, Sb, and REE. The geophysical data indicate that post-caldera collapse intrusions were important in formation of the hydrothermal systems. An aeromagnetic low along the E caldera margin reflects an intrusion at a depth of 2 km associated with the near-surface McDermitt-hot-spring-type Hg-Sb deposit, and the deeper level, high-sulfidation Ga-REE occurrence. The Li deposits on the W side of the caldera are associated with a series of low amplitude, small diameter aeromagnetic anomalies that form a continuous

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

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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.

Trends and determining factors associated with adherence to antiretroviral therapy (ART in Cameroon: a systematic review and analysis of the CAMPS trial

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Mbuagbaw Lawrence

2012-12-01

Full Text Available Abstract Background The benefits of antiretroviral therapy (ART cannot be experienced if they are not taken as prescribed. Yet, not all causes of non-adherence are dependent on the patient. Having to pay for medication reduces adherence rates. Non- adherence has severe public health implications which must be addressed locally and globally. This paper seeks to describe the trends in adherence rates reported in Cameroon and to investigate the determinants of adherence to ART in the Cameroon Mobile Phone SMS (CAMPS trial. Methods We conducted a systematic review of electronic databases (PubMed, Google Scholar, Web of Science, CINAHL, EMBASE and PSYCINFO for publications on adherence to ART in Cameroon (from January 1999 to May 2012 and described the trend in reported adherence rates and the factors associated with adherence. Data were extracted in duplicate. We used multivariable analyses on the baseline data for 200 participants in the CAMPS trial to determine the factors associated with adherence in four models using different measures of adherence (more than 90% or 95% on the visual analogue scale, no missed doses and a composite measure: 100% on the visual analogue scale, no missed doses and all pills taken on time. Results We identified nine studies meeting our inclusion criteria. Adherence to ART in Cameroon has risen steadily between 2000 and 2010, corresponding to reductions in the cost of medication. The factors associated with adherence to ART in Cameroon are grouped into patient, medication and disease related factors. We also identified factors related to the health system and the patient-provider relationship. In the CAMPS trial, education, side effects experienced and number of reminder methods were found to improve adherence, but only using multiple reminder methods was associated with better adherence in all the regression models (Adjusted Odds Ratio [AOR] 4.11, 95% Confidence Interval [CI] 1.89, 8.93; p Conclusions Reducing the

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

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Fontem, DA.

2003-01-01

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

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.

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

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F. J. Muafor

2014-01-01

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

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

Science.gov (United States)

Jaza Folefack, Achille Jean

2009-05-01

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

Modelling ground deformation patterns associated with volcanic processes at the Okataina Volcanic Centre

Science.gov (United States)

Holden, L.; Cas, R.; Fournier, N.; Ailleres, L.

2017-09-01

The Okataina Volcanic Centre (OVC) is one of two large active rhyolite centres in the modern Taupo Volcanic Zone (TVZ) in the North Island of New Zealand. It is located in a complex section of the Taupo rift, a tectonically active section of the TVZ. The most recent volcanic unrest at the OVC includes the 1315 CE Kaharoa and 1886 Tarawera eruptions. Current monitoring activity at the OVC includes the use of continuous GPS receivers (cGPS), lake levelling and seismographs. The ground deformation patterns preceding volcanic activity the OVC are poorly constrained and restricted to predictions from basic modelling and comparison to other volcanoes worldwide. A better understanding of the deformation patterns preceding renewed volcanic activity is essential to determine if observed deformation is related to volcanic, tectonic or hydrothermal processes. Such an understanding also means that the ability of the present day cGPS network to detect these deformation patterns can also be assessed. The research presented here uses the finite element (FE) modelling technique to investigate ground deformation patterns associated with magma accumulation and diking processes at the OVC in greater detail. A number of FE models are produced and tested using Pylith software and incorporate characteristics of the 1315 CE Kaharoa and 1886 Tarawera eruptions, summarised from the existing body of research literature. The influence of a simple ring fault structure at the OVC on the modelled deformation is evaluated. The ability of the present-day continuous GPS (cGPS) GeoNet monitoring network to detect or observe the modelled deformation is also considered. The results show the modelled horizontal and vertical displacement fields have a number of key features, which include prominent lobe based regions extending northwest and southeast of the OVC. The results also show that the ring fault structure increases the magnitude of the displacements inside the caldera, in particular in the

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…

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

Science.gov (United States)

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

2014-01-08

Studies in different parts of the world have implicated money as a vehicle for transmission of pathogens. Such information which is necessary to facilitate infection control strategies is lacking in many sub-Saharan countries including Cameroon. This study analyzed the Franc de la Communauté Financiere d'Afrique (Franc CFA), the currency used in Cameroon and other countries in the Central African sub-region, as a potential vehicle for transmission of pathogenic bacteria and fungi, particularly drug-resistant strains, to generate findings which could create awareness on currency contamination and serve as a guide when formulating health policies on currency. Two hundred and thirteen currency samples representing various denominations of notes and coins randomly collected from diverse sources in Buea, Cameroon were analyzed for bacteria and fungi. The sensitivity of bacterial isolates to antibiotics was tested using the disc diffusion method. The relationship between contamination and physical state, source or denomination of currency was assessed using the χ2 test. All statistics were discussed at 0.05 significance level. Two hundred (93.9%) samples were contaminated with notes (96.6%) showing higher contamination than coins (88.2%). Uncirculated (mint) samples showed no contamination. There was a significant difference (PCFA franc circulating in Buea could serve as a vehicle for transmission of drug resistant pathogenic or potential organisms and contamination could be due to currency usage and handling as mint notes were not contaminated. Hygiene practices during or after handling currency is greatly encouraged to prevent infection.

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 (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 hazardous eruptions in Chile, Colombia, Ecuador, and Peru has spurred significant

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

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

Directory of Open Access Journals (Sweden)

Serge C Billong

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

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

Science.gov (United States)

Billong, Serge C; Fokam, Joseph; Nkwescheu, Armand S; Kembou, Etienne; Milenge, Pascal; Tsomo, Zephirin; Dion, Grace Ngute; Aghokeng, Avelin F; Mpoudi, Eitel N; Ndumbe, Peter M; Colizzi, Vittorio; Elat Nfetam, Jean B

2012-01-01

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

Crustal structure beneath Cameroon from EGM2008

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Ngatchou Heutchi Evariste

2014-02-01

Full Text Available We used the Earth Gravitational Model (EGM2008 data sets to analyze the regional gravity anomalies and to study the underground structures in Cameroon. We first created a high-resolution Free-Air anomaly database, then corrected the gravity field of the topographic effect by using ETOPOl DEM with a resolution of 0.01° to obtain the Bouguer anomaly, then applied a multi-scale wavelet-analysis technique to separate the gravity-field components into different parts of shallow-to-deep origins, and finally used the logarithmic power spectrum technique to obtain detailed images and corresponding source depths as well as certain lateral inhomogeneity of structure density. The anomalies of shallow origin show successive elongated gravity “highs” and “lows” attributable to subsurface Tertiary and lower Cretaceous undulations. Our results are in good agreement with previous investigations.

Timing of Premarital Intercourse in Bandjoun (West Cameroon

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Zacharie Tsala Dimbuene

2013-03-01

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

Mechanisms for Quality Assurance of Universities in Cameroon

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Joseph BESONG BESONG

2016-06-01

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

Uncovering high rates of unsafe injection equipment reuse in rural Cameroon: validation of a survey instrument that probes for specific misconceptions

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Reid Savanna R

2011-02-01

Full Text Available Abstract Background Unsafe reuse of injection equipment in hospitals is an on-going threat to patient safety in many parts of Africa. The extent of this problem is difficult to measure. Standard WHO injection safety assessment protocols used in the 2003 national injection safety assessment in Cameroon are problematic because health workers often behave differently under the observation of visitors. The main objective of this study is to assess the extent of unsafe injection equipment reuse and potential for blood-borne virus transmission in Cameroon. This can be done by probing for misconceptions about injection safety that explain reuse without sterilization. These misconceptions concern useless precautions against cross-contamination, i.e. "indirect reuse" of injection equipment. To investigate whether a shortage of supply explains unsafe reuse, we compared our survey data against records of purchases. Methods All health workers at public hospitals in two health districts in the Northwest Province of Cameroon were interviewed about their own injection practices. Injection equipment supply purchase records documented for January to December 2009 were compared with self-reported rates of syringe reuse. The number of HIV, HBV and HCV infections that result from unsafe medical injections in these health districts is estimated from the frequency of unsafe reuse, the number of injections performed, the probability that reused injection equipment had just been used on an infected patient, the size of the susceptible population, and the transmission efficiency of each virus in an injection. Results Injection equipment reuse occurs commonly in the Northwest Province of Cameroon, practiced by 44% of health workers at public hospitals. Self-reported rates of syringe reuse only partly explained by records on injection equipment supplied to these hospitals, showing a shortage of syringes where syringes are reused. Injection safety interventions could

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

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

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.

Holocene volcanic geology, volcanic hazard, and risk on Taveuni, Fiji

International Nuclear Information System (INIS)

Cronin, S.J.; Neall, V.E.

2001-01-01

The Holocene volcanic geology of Taveuni has been mapped in order to produce a volcanic hazard and risk assessment for the island. Taveuni is the third-largest island of the Fiji group and home to 14,500 people. At least cubic km 2.7 of olivine-alkali-basalt magma was erupted from over 100 events throughout the Holocene. Vents are concentrated along a northeast-striking rift zone that is parallel to other regional structural trends. There is an overall trend of younging southward along the rift. Holocene lavas and tephras are grouped within six newly defined eruptive periods, established on a basis of radiocarbon dating. Within these periods, 14 tephra layers, useful as local marker horizons, are recognised. At least 58% of Holocene eruptions produced lava flows, while almost all produced some tephra. Individual eruption event volumes ranged between 0.001 and cubic km 0.20 (dense rock equivalent). Many eruptions involved at least some phases of phreatic and/or phreato-magmatic activity, although dominant hydrovolcanic activity was limited to only a few events. A volcanic hazard map is presented, based on the Holocene geology map and statistical analyses of eruption recurrence. The highest levels of ground-based and near-vent hazards are concentrated along the southern portion of the island's rift axis, with the paths of initial lava flows predicted from present topography. Tephra fall hazards are based on eruption parameters interpreted from mapped Holocene tephra layers. Hawaiian explosive-style eruptions appear to be a dominant eruptive process, with prevailing low-level (<3 km) southeasterly winds dispersing most tephra to the northwestern quadrant. Vulnerable elements (population centres, infrastructure, and economy) on Taveuni have been considered in deriving a volcanic risk assessment for the island. A number of infrastructural and subdivision developments are either under way or planned for the island, driven by its highly fertile soils and availability of

Geomorphological Approach for Regional Zoning In The Merapi Volcanic Area

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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.

Deprivation profile in Cameroon: A combined analysis of Poverty and Social Exclusion

OpenAIRE

Miamo Wendji, Clovis

2015-01-01

In this study, we analyze the privations welfare in Cameroon considering poverty and social exclusion. The framework provided by the capability approach and construction of indicators of poverty and social exclusion by the fuzzy method from ECAM III survey data shows that the overall level of poverty and social exclusion (respectively 0.4008 and 0.2291), are still very high. The definition of two-dimensional profile of welfare deprivation reveals that the determinants of deprivation are diffe...

Investigating Gender Wage Gap in Employment: A Microeconometric Type-Analysis for Cameroon

OpenAIRE

Mbratana, Taoufiki; Kenne Fotié, Andrée

2017-01-01

Using the 2007 Cameroon Household Consumption Survey, we study gender wage disparity in pay-employment and self-employment. The main question considered in this paper is to know why women pay-employment and self-employment wages are relatively low. More generally, what is the underlying factors generating and explained wage gap between men and women householder in employment? To answer to our question, firstly, we use the Oaxaca-Blinder (OB) Decomposition to explain wage gap. Afterward, we pe...

Transition of neogene arc volcanism in central-western Hokkaido, viewed from K-Ar ages, style of volcanic activity, and bulk rock chemistry

Energy Technology Data Exchange (ETDEWEB)

Hirose, Wataru; Iwasaki, Miyuki; Nakagawa, Mitsuhiro [Hokkaido Univ., Sapporo (Japan)

2000-02-01

Spatial and temporal variations in late Cenozoic volcanism of southwestern Hokkaido at the northern end of NE-Japan arc have been clarified by 261 K-Ar and 76 FT ages including 49 newly determined K-Ar ages, volcanic stratigraphy, physical volcanology and whole-rock geochemistry. Arc volcanism characterized by rocks with low-Ti and Nb, and by across-arc increase in K{sub 2}O content in these rocks has continued at least since 12 Ma. Based on volcanic stratigraphy, physical volcanology and whole-rock geochemistry, volcanism after 12 Ma can be subdivided into 4 stages, 12-5, 5-1.7, and 1.7-0 Ma. The volcanism from 12 Ma to 5 Ma extended northward widely compared with distribution of Quaternary arc volcanism (1.7-0 Ma). This suggests that the arc trench junction between Kuril and NE-Japan arc's trenches was located about 100 km northward from the present position. Since around 5 Ma until 1.7 Ma, different type of volcanism under local extension field, characterized by a group of monogenetic volcanoes of alkali basalt and shield volcanoes of calc-alkaline andesite, had occurred at northern end of the volcanic region (Takikawa-Mashike region). During and after this volcanism, the northern edge of arc volcanism in the area has migrated southward. This suggests that the trench junction has migrated about 100 km southward since {approx}5 Ma. The quaternary arc volcanism (1.7-0 Ma) has been restricted at the southern part of the region. The volcanism since 12 Ma might be influenced by oblique subduction of Pacific plate beneath Kuril arc, resulting in the formation of local back arc basin at the junction and to southward migration of the trench junction. (author)

Factors associated with perception of risk of contracting HIV among secondary school female learners in Mbonge subdivision of rural Cameroon.

Science.gov (United States)

Tarkang, Elvis Enowbeyang

2014-01-01

Since learners in secondary schools fall within the age group hardest hit by HIV/AIDS, it is obvious that these learners might be at high risk of contracting HIV/AIDS. However, little has been explored on the perception of risk of contracting HIV among secondary school learners in Cameroon. This study aimed at examining the perception of risk of contracting HIV among secondary school learners in Mbonge subdivision of rural Cameroon using the Health Belief Model (HBM) as framework. A quantitative, correlational design was adopted, using a self-administered questionnaire to collect data from 210 female learners selected through disproportional, stratified, simple random sampling technique, from three participating senior secondary schools. Statistics were calculated using SPSS version 20 software program. Only 39.4% of the respondents perceived themselves to be at high risk of contracting HIV, though the majority, 54.0% were sexually active. Multinomial logistic regression analyses show that sexual risk behaviours (p=0.000) and the Integrated Value Mapping (IVM) of the perception components of the HBM are the most significant factors associated with perception of risk of contracting HIV at the level p<0.05. The findings of this study can play an instrumental role in the development of effective preventive and interventional messages for adolescents in Cameroon.

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

Science.gov (United States)

Pearshouse, Richard; Klein, Alana

2006-12-01

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

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

Psychosocial stressors of sickle cell disease on adult patients in Cameroon.

Science.gov (United States)

Wonkam, Ambroise; Mba, Caryl Zameyo; Mbanya, Dora; Ngogang, Jeanne; Ramesar, Raj; Angwafo, Fru F

2014-12-01

Sickle Cell Disease (SCD) is a debilitating illness that affects quality of life. Studies of the psychosocial burden of SCD on patients have been rarely reported in Africa. We used a quantitative method, with face-to-face administered questionnaires, to study indices of psychosocial stressors on adult SCD patients in Cameroon. The questionnaire included a 36-item stress factors scale evaluating general perceptions of stress and five main stressors' domain: disease factors, hospital factors, financial factors, family factors and quality of personal-life factors. Items pertaining to psychosocial stressors involved four response options with increasing severity: 0, 1, 2 or 3. Non-parametric tests were used for analysis. The majority of the 83 participants were urban dwellers, female, 20-30 years old, single, unemployed, with at least a secondary or tertiary education. Median age at diagnosis was 100 months; 47.8% had >3 painful vaso-oclusive crises annually. Only 4.8% had been treated with hydroxyurea. The majority reported moderate to severe difficulty coping with SCD. The "degree of clinical severity" category displayed the highest median score (2.0), while familial stressors showed the lowest (0.8). Being female, married, with low education level, an additional affected sibling and low direct income were significantly associated with specific stressors' categories. In Cameroon, there is an urgent need to implement policies that ensure affordable access to health-care and practices to reduce SCD morbidity and improve patients' quality of life.

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.

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...

Slab dehydration in Cascadia and its relationship to volcanism, seismicity, and non-volcanic tremor

Science.gov (United States)

Delph, J. R.; Levander, A.; Niu, F.

2017-12-01

The characteristics of subduction beneath the Pacific Northwest (Cascadia) are variable along strike, leading to the segmentation of Cascadia into 3 general zones: Klamath, Siletzia, and Wrangelia. These zones show marked differences in tremor density, earthquake density, seismicity rates, and the locus and amount of volcanism in the subduction-related volcanic arc. To better understand what controls these variations, we have constructed a 3D shear-wave velocity model of the upper 80 km along the Cascadia margin from the joint inversion of CCP-derived receiver functions and ambient noise surface wave data using 900 temporary and permanent broadband seismic stations. With this model, we can investigate variations in the seismic structure of the downgoing oceanic lithosphere and overlying mantle wedge, the character of the crust-mantle transition beneath the volcanic arc, and local to regional variations in crustal structure. From these results, we infer the presence and distribution of fluids released from the subducting slab and how they affect the seismic structure of the overriding lithosphere. In the Klamath and Wrangelia zones, high seismicity rates in the subducting plate and high tremor density correlate with low shear velocities in the overriding plate's forearc and relatively little arc volcanism. While the cause of tremor is debated, intermediate depth earthquakes are generally thought to be due to metamorphic dehydration reactions resulting from the dewatering of the downgoing slab. Thus, the seismic characteristics of these zones combined with rather sparse arc volcanism may indicate that the slab has largely dewatered by the time it reaches sub-arc depths. Some of the water released during earthquakes (and possibly tremor) may percolate into the overriding plate, leading to slow seismic velocities in the forearc. In contrast, Siletzia shows relatively low seismicity rates and tremor density, with relatively higher shear velocities in the forearc

Seismological evidence for a sub-volcanic arc mantle wedge beneath the Denali volcanic gap, Alaska

Science.gov (United States)

McNamara, D.E.; Pasyanos, M.E.

2002-01-01

Arc volcanism in Alaska is strongly correlated with the 100 km depth contour of the western Aluetian Wadati-Benioff zone. Above the eastern portion of the Wadati-Benioff zone however, there is a distinct lack of volcanism (the Denali volcanic gap). We observe high Poisson's ratio values (0.29-0.33) over the entire length of the Alaskan subduction zone mantle wedge based on regional variations of Pn and Sn velocities. High Poisson's ratios at this depth (40-70 km), adjacent to the subducting slab, are attributed to melting of mantle-wedge peridotites, caused by fluids liberated from the subducting oceanic crust and sediments. Observations of high values of Poisson's ratio, beneath the Denali volcanic gap suggest that the mantle wedge contains melted material that is unable to reach the surface. We suggest that its inability to migrate through the overlying crust is due to increased compression in the crust at the northern apex of the curved Denali fault.

Farmer's perception of the effects of eartworms on soil fertility and crop performance in southern Cameroon

NARCIS (Netherlands)

Madong à Birang,; Hauser, S.; Amougou, D.L.

2003-01-01

The knowledge and perception of the effects of earthworms on soil fertility and crop growth was surveyed in a humid forest zone of southern Cameroon. A total of 215 farmers were interviewed in seven villages: two villages were near the capital Yaounde, severely deforested with a high land-use

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

Volcanic Gases and Hot Spring Water to Evaluate the Volcanic Activity of the Mt. Baekdusan

Science.gov (United States)

Yun, S. H.; Lee, S.; Chang, C.

2017-12-01

This study performed the analysis on the volcanic gases and hot spring waters from the Julong hot spring at Mt. Baekdu, also known as Changbaishan on the North Korea(DPRK)-China border, during the period from July 2015 to August 2016. Also, we confirmed the errors that HCO3- concentrations of hot spring waters in the previous study (Lee et al. 2014) and tried to improve the problem. Dissolved CO2 in hot spring waters was analyzed using gas chromatograph in Lee et al.(2014). Improving this, from 2015, we used TOC-IC to analysis dissolved CO2. Also, we analyzed the Na2CO3 standard solutions of different concentrations using GC, and confirmed the correlation between the analytical concentrations and the real concentrations. However, because the analytical results of the Julong hot spring water were in discord with the estimated values based on this correlation, we can't estimate the HCO3-concentrations of 2014 samples. During the period of study, CO2/CH4 ratios in volcanic gases are gradually decreased, and this can be interpreted in two different ways. The first interpretation is that the conditions inside the volcanic edifice are changing into more reduction condition, and carbon in volcanic gases become more favorable to distribute into CH4 or CO than CO2. The second interpretation is that the interaction between volcanic gases and water becomes greater than past, and the concentrations of CO2which have much higher solubility in water decreased, relatively. In general, the effect of scrubbing of volcanic gas is strengthened during the quiet periods of volcanic activity rather than active periods. Meanwhile, the analysis of hot spring waters was done on the anion of acidic gases species, the major cations, and some trace elements (As, Cd, Re).This work was funded by the Korea Meteorological Administration Research and Development Program under Grant KMIPA 2015-3060.

Evaluation of phosphorus sorption characteristics of soils from the ...

African Journals Online (AJOL)

The evaluation of phosphorus sorption characteristics of soils and their relation to soil properties from the Bambouto sequence of Baranka 1, Baranka 2, Femock 1 and Femock 2 has been studied. Phosphorus, an essential plant nutrient, is often not readily available to plants and this deficiency tends to limit plant growth.

Disruptive event analysis: volcanism and igneous intrusion

International Nuclear Information System (INIS)

Crowe, B.M.

1979-01-01

Three basic topics are addressed for the disruptive event analysis: first, the range of disruptive consequences of a radioactive waste repository by volcanic activity; second, the possible reduction of the risk of disruption by volcanic activity through selective siting of a repository; and third, the quantification of the probability of repository disruption by volcanic activity

Timing and compositional evolution of Late Pleistocene to Holocene volcanism within the Harrat Rahat volcanic field, Kingdom of Saudi Arabia

Science.gov (United States)

Stelten, M. E.; Downs, D. T.; Dietterich, H. R.

2017-12-01

Harrat Rahat is one of the largest ( 20,000 km2) of 15 active Cenozoic volcanic fields that stretch 3,000 km along the western Arabian Peninsula from Yemen to Syria. The Harrat Rahat volcanic field is 310 km long (N-S) by 75 km wide (E-W), and is dominated by alkalic basalts with minor hawaiite, mugearite, benmoreite, and trachyte eruptives. The timing of volcanism within greater Harrat Rahat is poorly constrained, but field relations and geochronology indicate that northern Harrat Rahat hosted the most recent eruptions. To better constrain the timing and compositional evolution of Harrat Rahat during this recent phase, we present 743 geochemical analyses, 144 40Ar/39Ar ages, and 9 36Cl exposure ages for volcanic strata from northernmost Harrat Rahat. These data demonstrate that volcanism has been ongoing from at least 1.2 Ma to the present, with the most recent eruption known from historical accounts at 1256 CE. Basalt has erupted persistently from 1.2 Ma to the present, but more evolved volcanism has been episodic. Benmoreite erupted at 1.1 Ma and between 550 to 400 ka. Trachytic volcanism has only occurred over the past 150 ka, with the most recent eruption at 5 ka. Aside from the well-documented basaltic eruption at 1256 CE, prior workers interpreted 6 additional basaltic eruptions during the Holocene. However, our 36Cl exposure ages demonstrate that these erupted between 60 to 13 ka. Interestingly, in the northern part of our field area, where the spatial density of volcanic vents is low, young volcanism (<150 ka) is dominated by basaltic eruptions. Conversely, young volcanism in the southern part of our field area, where volcanic vent density is high, is dominated by trachyte. This observation is consistent with a process wherein the time-integrated effects of basaltic influx into the crust in the south produced a mafic intrusive complex, through which younger basaltic magmas cannot ascend. Instead, these magmas stall and produce trachyte, likely through

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

Climatic impact of volcanic eruptions

Science.gov (United States)

Rampino, Michael R.

1991-01-01

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

The acceptability of volunteer, repeat blood donations in a hospital setting in the Adamaoua region of Cameroon.

Science.gov (United States)

Rolseth, S; Stange, P; Adamou, D; Roald, B; Danki-Sillong, F; Jourdan, P

2014-12-01

The knowledge of factors that may influence blood donation in Cameroon is limited. The objectives of this study are to assess the characteristics of previous and potential blood donors by exploring the religious beliefs, and knowledge and understanding of blood donations among individuals present at a district hospital. Forty-nine in-depth, semi-structured interviews were conducted among consenting, randomly selected 18 years or older community members present at a district hospital in the Adamaoua region during October and November 2011. Ninety-eight per cent (48/49) of the individuals present at this district hospital had heard of blood transfusions. Forty-seven per cent (23/49) had not previously been asked to donate blood; however, 94% (44/47) said that they would donate if given the opportunity. Thirty-three per cent (16/49) had previously donated blood to family members or for replacement, and 81% of these said they would repeat donations. The majority of both donors and non-donors were motivated to donate blood for altruistic reasons. The findings suggest that community members present at this district hospital in Cameroon may be recruited for repeat blood donations. Although the altruistic motivation to donate blood suggests that donors could be recruited from a district hospital population, targeted information about blood donations and accessible blood transfusion services need to be put in place. The study may add to the understanding of the preconditions for blood donations and the possibility to establish sustainable blood transfusion services in the Adamaoua region in Cameroon. © 2014 British Blood Transfusion Society.

Do the factors associated with female HIV infection vary by socioeconomic status in Cameroon?

Science.gov (United States)

Mumah, Joyce N; Jackson-Smith, Douglas

2014-07-01

One of the most consistent findings in social epidemiology is an inverse relationship between indicators of SES and most types of illness. However, a growing body of research on HIV in sub-Saharan Africa suggests an intriguing reversal of this pattern, particularly with respect to HIV among women. In Cameroon, specifically, high-SES women have higher rates of HIV infection compared with low-SES women. Using data from the 2004 Cameroon DHS, this study explored the relationships between SES and HIV and tested a multivariate model designed to highlight the distinctive factors associated with increased risk of HIV among women in different SES classes. The results revealed that high-SES women who reported engaging in riskier sexual behaviour had the highest levels of HIV infection. Surprisingly, among this group increased knowledge of HIV, more domestic decision-making authority and access to health care did not reduce vulnerability. Meanwhile, among low-SES women relative gender inequality was significantly related to HIV risk. Specifically, among this group of women, having a partner with higher education was strongly associated with greater HIV risk. The results suggest that different approaches targeting each sub-group are needed to effectively combat the disease.

Self-disclosure of HIV status, disclosure counseling, and retention in HIV care in Cameroon.

Science.gov (United States)

Breger, Tiffany L; Newman, Jamie E; Mfangam Molu, Brigitte; Akam, Wilfred; Balimba, Ashu; Atibu, Joseph; Kiumbu, Modeste; Azinyue, Innocent; Hemingway-Foday, Jennifer; Pence, Brian W

2017-07-01

Poor retention in care is common among HIV-positive adults in sub-Saharan Africa settings and remains a key barrier to HIV management. We quantify the associations of disclosure of HIV status and referral to disclosure counseling with successful retention in care using data from three Cameroon clinics participating in the Phase 1 International epidemiologic Databases to Evaluate AIDS Central Africa cohort. Of 1646 patients newly initiating antiretroviral therapy between January 2008 and January 2011, 43% were retained in care following treatment initiation. Self-disclosure of HIV status to at least one person prior to treatment initiation was associated with a minimal increase in the likelihood of being retained in care (risk ratio [RR] = 1.14; 95% confidence interval (CI): 0.94, 1.38). However, referral to disclosure counseling was associated with a moderate increase in retention (RR = 1.37; 95% CI: 1.21, 1.55) and was not significantly modified by prior disclosure status (p = .3). Our results suggest that while self-disclosure may not significantly improve retention among patients receiving care at these Cameroon sites, counseling services may play an important role regardless of prior disclosure status.

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

Science.gov (United States)

Mollel, Godwin F; Swisher, Carl C

2012-08-01

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

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

Directory of Open Access Journals (Sweden)

Albert N. Kimbu

2012-03-01

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

Using Satellite Observations to Evaluate the AeroCOM Volcanic Emissions Inventory and the Dispersal of Volcanic SO2 Clouds in MERRA

Science.gov (United States)

Hughes, Eric J.; Krotkov, Nickolay; da Silva, Arlindo; Colarco, Peter

2015-01-01

Simulation of volcanic emissions in climate models requires information that describes the eruption of the emissions into the atmosphere. While the total amount of gases and aerosols released from a volcanic eruption can be readily estimated from satellite observations, information about the source parameters, like injection altitude, eruption time and duration, is often not directly known. The AeroCOM volcanic emissions inventory provides estimates of eruption source parameters and has been used to initialize volcanic emissions in reanalysis projects, like MERRA. The AeroCOM volcanic emission inventory provides an eruptions daily SO2 flux and plume top altitude, yet an eruption can be very short lived, lasting only a few hours, and emit clouds at multiple altitudes. Case studies comparing the satellite observed dispersal of volcanic SO2 clouds to simulations in MERRA have shown mixed results. Some cases show good agreement with observations Okmok (2008), while for other eruptions the observed initial SO2 mass is half of that in the simulations, Sierra Negra (2005). In other cases, the initial SO2 amount agrees with the observations but shows very different dispersal rates, Soufriere Hills (2006). In the aviation hazards community, deriving accurate source terms is crucial for monitoring and short-term forecasting (24-h) of volcanic clouds. Back trajectory methods have been developed which use satellite observations and transport models to estimate the injection altitude, eruption time, and eruption duration of observed volcanic clouds. These methods can provide eruption timing estimates on a 2-hour temporal resolution and estimate the altitude and depth of a volcanic cloud. To better understand the differences between MERRA simulations and volcanic SO2 observations, back trajectory methods are used to estimate the source term parameters for a few volcanic eruptions and compared to their corresponding entry in the AeroCOM volcanic emission inventory. The nature of

Retrospective analysis of the prevalence of and factors associated with condom use among young HIV-infected women in Cameroon

Directory of Open Access Journals (Sweden)

Mariecel Pilapil

2016-01-01

Full Text Available Objectives: Young women are more likely to be infected with HIV globally, in sub-Saharan Africa, and in Cameroon. Despite its clear clinical and public health benefits, condom use among HIV-infected women continues to be low. The objective of this study was to describe the prevalence of inconsistent condom use among HIV-infected women in Cameroon and the factors associated with it. Methods: We conducted a cross-sectional study of HIV-infected young women aged 17–26 years from three semi-urban HIV clinics in the Northwest Region of Cameroon. This study was a subgroup analysis of a previously reported study on inconsistent condom use in HIV-infected and -uninfected youth. Inconsistent condom use was defined as reporting “sometimes” or “never” to questions regarding frequency of condom use. Logistic regression modeling was used to determine factors associated with inconsistent condom use. Results: A total of 84 participants were recruited and submitted completed questionnaires for analysis. Median age was 24 years (interquartile range = 22–25 and the median age at HIV diagnosis was 21 years (interquartile range = 20–23. Fifty percent of the participants reported no prior schooling or only primary school education. Overall, 61/84 (73% reported inconsistent condom use. After adjusting for potential confounders, education to the secondary school level was protective against inconsistent condom use (odds ratio = 0.19; confidence interval: 0.04–0.95, and having ≥2 pregnancies was associated with inconsistent condom use (odds ratio = 7.52; confidence interval: 1.67–34.00. Conclusion: There is a high prevalence of inconsistent condom use among young HIV-infected women in Cameroon, which appears to be associated with lower levels of educational attainment and higher parity. Further larger studies assessing the factors associated with poor condom use in this population are warranted and may inform public health

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......Due to the infectious nature of some clinical waste, poor disposal practices have sparked concern regarding the impact on public health and the environment. Lack of sufficient knowledge of the associated risks may be a strong factor contributing to inadequate disposal practices. We conducted......, 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...

Assessment of volcanic hazards, vulnerability, risk and uncertainty (Invited)

Science.gov (United States)

Sparks, R. S.

2009-12-01

A volcanic hazard is any phenomenon that threatens communities . These hazards include volcanic events like pyroclastic flows, explosions, ash fall and lavas, and secondary effects such as lahars and landslides. Volcanic hazards are described by the physical characteristics of the phenomena, by the assessment of the areas that they are likely to affect and by the magnitude-dependent return period of events. Volcanic hazard maps are generated by mapping past volcanic events and by modelling the hazardous processes. Both these methods have their strengths and limitations and a robust map should use both approaches in combination. Past records, studied through stratigraphy, the distribution of deposits and age dating, are typically incomplete and may be biased. Very significant volcanic hazards, such as surge clouds and volcanic blasts, are not well-preserved in the geological record for example. Models of volcanic processes are very useful to help identify hazardous areas that do not have any geological evidence. They are, however, limited by simplifications and incomplete understanding of the physics. Many practical volcanic hazards mapping tools are also very empirical. Hazards maps are typically abstracted into hazards zones maps, which are some times called threat or risk maps. Their aim is to identify areas at high levels of threat and the boundaries between zones may take account of other factors such as roads, escape routes during evacuation, infrastructure. These boundaries may change with time due to new knowledge on the hazards or changes in volcanic activity levels. Alternatively they may remain static but implications of the zones may change as volcanic activity changes. Zone maps are used for planning purposes and for management of volcanic crises. Volcanic hazards maps are depictions of the likelihood of future volcanic phenomena affecting places and people. Volcanic phenomena are naturally variable, often complex and not fully understood. There are

Martian volcanism: A review

International Nuclear Information System (INIS)

Carr, M.H.

1987-01-01

Martian volcanism is reviewed. It is emphasized that lava plains constitute the major type of effusive flow, and can be differentiated by morphologic characteristics. Shield volcanoes, domes, and patera constitute the major constructional landforms, and recent work has suggested that explosive activity and resulting pyroclastic deposits may have been involved with formation of some of the small shields. Analysis of morphology, presumed composition, and spectroscopic data all indicate that Martian volcanism was dominantly basaltic in composition

Volcanic eruptions and solar activity

Science.gov (United States)

Stothers, Richard B.

1989-01-01

The historical record of large volcanic eruptions from 1500 to 1980 is subjected to detailed time series analysis. In two weak but probably statistically significant periodicities of about 11 and 80 yr, the frequency of volcanic eruptions increases (decreases) slightly around the times of solar minimum (maximum). Time series analysis of the volcanogenic acidities in a deep ice core from Greenland reveals several very long periods ranging from about 80 to about 350 yr which are similar to the very slow solar cycles previously detected in auroral and C-14 records. Solar flares may cause changes in atmospheric circulation patterns that abruptly alter the earth's spin. The resulting jolt probably triggers small earthquakes which affect volcanism.

Volcanic hazards of the Idaho National Engineering Laboratory and adjacent areas

International Nuclear Information System (INIS)

Hackett, W.R.; Smith, R.P.

1994-12-01

Potential volcanic hazards are assessed, and hazard zone maps are developed for the Idaho National Engineering Laboratory (INEL) and adjacent areas. The basis of the hazards assessment and mapping is the past volcanic history of the INEL region, and the apparent similarity of INEL volcanism with equivalent, well-studied phenomena in other regions of active volcanism, particularly Hawaii and Iceland. The most significant hazards to INEL facilities are associated with basaltic volcanism, chiefly lava flows, which move slowly and mainly threaten property by inundation or burning. Related hazards are volcanic gases and tephra, and ground disturbance associated with the ascent of magma under the volcanic zones. Several volcanic zones are identified in the INEL area. These zones contain most of the volcanic vents and fissures of the region and are inferred to be the most probable sites of future INEL volcanism. Volcanic-recurrence estimates are given for each of the volcanic zones based on geochronology of the lavas, together with the results of field and petrographic investigations concerning the cogenetic relationships of INEL volcanic deposits and associated magma intrusion. Annual probabilities of basaltic volcanism within the INEL volcanic zones range from 6.2 x 10 -5 per year (average 16,000-year interval between eruptions) for the axial volcanic zone near the southern INEL boundary and the Arco volcanic-rift zone near the western INEL boundary, to 1 x 10 -5 per year (average 100,000-year interval between eruptions) for the Howe-East Butte volcanic rift zone, a geologically old and poorly defined feature of the central portion of INEL. Three volcanic hazard zone maps are developed for the INEL area: lava flow hazard zones, a tephra (volcanic ash) and gas hazard zone, and a ground-deformation hazard zone. The maps are useful in land-use planning, site selection, and safety analysis

[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.

The prevalence of human immunodeficiency virus among pregnant women attending a hospital in the Moungo district, Cameroon

NARCIS (Netherlands)

van dan Meeberg, P. C.; Kooiman, R. C.; Buisman, N. J.; Goudsmit, J.; Lange, J. M.; Bannenberg, A. F.

1989-01-01

A seroepidemiological survey conducted from January to May 1986 among 650 pregnant women from mixed rural/urban origin in the Moungo district, Cameroon, revealed a very low prevalence of antibodies to human immunodeficiency viruses (HIV). One subject appeared to be infected with HIV 2. This is

Prevalence and predictors of major depression in HIV-infected patients on antiretroviral therapy in Bamenda, a semi-urban center in Cameroon.

Directory of Open Access Journals (Sweden)

Bradley N Gaynes

Full Text Available Recent blue-ribbon panel reports have concluded that HIV treatment programs in less wealthy countries must integrate mental health identification and treatment into normal HIV clinical care and that research on mental health and HIV in these settings should be a high priority. We assessed the epidemiology of depression in HIV patients on antiretroviral therapy in a small urban setting in Cameroon by administering a structured interview for depression to 400 patients consecutively attending the Bamenda Regional Hospital AIDS Treatment Center. One in five participants met lifetime criteria for MDD, and 7% had MDD within the prior year. Only 33% had ever spoken with a health professional about depression, and 12% reported ever having received depression treatment that was helpful or effective. Over 2/3 with past-year MDD had severe or very severe episodes. The number of prior depressive episodes and the number of HIV symptoms were the strongest predictors of past-year MDD. The prevalence of MDD in Cameroon is as high as that of other HIV-associated conditions, such as tuberculosis and Hepatitis B virus, whose care is incorporated into World Health Organization guidelines. The management of depression needs to be incorporated in HIV-care guidelines in Cameroon and other similar settings.

Geochemical characteristics of the Jos-Plateau Basalts, North ...

African Journals Online (AJOL)

The Jos Plateau basalts, present Zr/Nb ratios (2.4-3.0) comparable to those of the alkali basalts of the lower Benue valley, and of the Cameroon volcanic line, suggesting that they were possibly derived from the same mantle source. Keywords: Jos Plateau, alkali basalt, mantle, partial melting, incompatible elements.

Stochastic Modeling of Past Volcanic Crises

Science.gov (United States)

Woo, Gordon

2018-01-01

The statistical foundation of disaster risk analysis is past experience. From a scientific perspective, history is just one realization of what might have happened, given the randomness and chaotic dynamics of Nature. Stochastic analysis of the past is an exploratory exercise in counterfactual history, considering alternative possible scenarios. In particular, the dynamic perturbations that might have transitioned a volcano from an unrest to an eruptive state need to be considered. The stochastic modeling of past volcanic crises leads to estimates of eruption probability that can illuminate historical volcanic crisis decisions. It can also inform future economic risk management decisions in regions where there has been some volcanic unrest, but no actual eruption for at least hundreds of years. Furthermore, the availability of a library of past eruption probabilities would provide benchmark support for estimates of eruption probability in future volcanic crises.

Rate of volcanism on Venus

International Nuclear Information System (INIS)

Fegley, B. Jr.; Prinn, R.G.

1988-07-01

The maintenance of the global H 2 SO 4 clouds on Venus requires volcanism to replenish the atmospheric SO 2 which is continually being removed from the atmosphere by reaction with calcium minerals on the surface of Venus. The first laboratory measurements of the rate of one such reaction, between SO 2 and calcite (CaCO 3 ) to form anhydrite (CaSO 4 ), are reported. If the rate of this reaction is representative of the SO 2 reaction rate at the Venus surface, then we estimate that all SO 2 in the Venus atmosphere (and thus the H 2 SO 4 clouds) will be removed in 1.9 million years unless the lost SO 2 is replenished by volcanism. The required rate of volcanism ranges from about 0.4 to about 11 cu km of magma erupted per year, depending on the assumed sulfur content of the erupted material. If this material has the same composition as the Venus surface at the Venera 13, 14 and Vega 2 landing sites, then the required rate of volcanism is about 1 cu km per year. This independent geochemically estimated rate can be used to determine if either (or neither) of the two discordant (2 cu km/year vs. 200 to 300 cu km/year) geophysically estimated rates is correct. The geochemically estimated rate also suggests that Venus is less volcanically active than the Earth

Global volcanic aerosol properties derived from emissions, 1990-2014, using CESM1(WACCM): VOLCANIC AEROSOLS DERIVED FROM EMISSIONS

Energy Technology Data Exchange (ETDEWEB)

Mills, Michael J. [Atmospheric Chemistry Observations and Modeling Laboratory, National Center for Atmospheric Research, Boulder Colorado USA; Schmidt, Anja [School of Earth and Environment, University of Leeds, Leeds UK; Easter, Richard [Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland Washington USA; Solomon, Susan [Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge Massachusetts USA; Kinnison, Douglas E. [Atmospheric Chemistry Observations and Modeling Laboratory, National Center for Atmospheric Research, Boulder Colorado USA; Ghan, Steven J. [Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland Washington USA; Neely, Ryan R. [School of Earth and Environment, University of Leeds, Leeds UK; National Centre for Atmospheric Science, University of Leeds, Leeds UK; Marsh, Daniel R. [Atmospheric Chemistry Observations and Modeling Laboratory, National Center for Atmospheric Research, Boulder Colorado USA; Conley, Andrew [Atmospheric Chemistry Observations and Modeling Laboratory, National Center for Atmospheric Research, Boulder Colorado USA; Bardeen, Charles G. [Atmospheric Chemistry Observations and Modeling Laboratory, National Center for Atmospheric Research, Boulder Colorado USA; Gettelman, Andrew [Atmospheric Chemistry Observations and Modeling Laboratory, National Center for Atmospheric Research, Boulder Colorado USA

2016-03-06

Accurate representation of global stratospheric aerosol properties from volcanic and non-volcanic sulfur emissions is key to understanding the cooling effects and ozone-loss enhancements of recent volcanic activity. Attribution of climate and ozone variability to volcanic activity is of particular interest in relation to the post-2000 slowing in the apparent rate of global average temperature increases, and variable recovery of the Antarctic ozone hole. We have developed a climatology of global aerosol properties from 1990 to 2014 calculated based on volcanic and non-volcanic emissions of sulfur sources. We have complied a database of volcanic SO2 emissions and plume altitudes for eruptions between 1990 and 2014, and a new prognostic capability for simulating stratospheric sulfate aerosols in version 5 of the Whole Atmosphere Community Climate Model, a component of the Community Earth System Model. Our climatology shows remarkable agreement with ground-based lidar observations of stratospheric aerosol optical depth (SAOD), and with in situ measurements of aerosol surface area density (SAD). These properties are key parameters in calculating the radiative and chemical effects of stratospheric aerosols. Our SAOD climatology represents a significant improvement over satellite-based analyses, which ignore aerosol extinction below 15 km, a region that can contain the vast majority of stratospheric aerosol extinction at mid- and high-latitudes. Our SAD climatology significantly improves on that provided for the Chemistry-Climate Model Initiative, which misses 60% of the SAD measured in situ. Our climatology of aerosol properties is publicly available on the Earth System Grid.

Hepatitis B virus exposure during childhood in Cameroon, Central African Republic and Senegal after the integration of HBV vaccine in the expanded program on immunization.

Science.gov (United States)

Rey-Cuille, Marie-Anne; Njouom, Richard; Bekondi, Claudine; Seck, Abdoulaye; Gody, Chrysostome; Bata, Petulla; Garin, Benoit; Maylin, Sarah; Chartier, Loic; Simon, François; Vray, Muriel

2013-10-01

More than 2 billion people worldwide have been exposed to hepatitis B virus (HBV). To prevent these infections, Senegal and Cameroon integrated the HBV vaccine into their Expanded Program on Immunization (EPI) in 2005, as did the Central African Republic (CAR) in 2008. We evaluated the prevalence of HBV exposure and infection after the integration of the HBV vaccine in the EPI. An observational cross-sectional study was conducted among the hospitalized children 3 months to 6 years of age in Cameroon, CAR and Senegal. Plasma was collected for the detection of anti-HBc, anti-HBs and hepatitis B surface antigen in children with anti-HBc and anti-HBs. Between April 2009 and May 2010, 1783 children were enrolled, 19.4% of whom were anti-HBc positive. The percentage of children with anti-HBc was 44.4% among the children younger than 6 months, decreasing after 6 months to reach 18.8% at 12 months. This decline was followed by a rapid increase in anti-HBc positivity rate in CAR observed as early as 12 months of age compared with Cameroon and Senegal, where the anti-HBc increased between 18 and 36 months of age, respectively. The prevalence of hepatitis B surface antigen-positive children was significantly higher in CAR than that in Cameroon and Senegal (5.1% versus 0.7% and 0.2%; P Senegal suggests a positive impact of HBV vaccination.

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

DEFF Research Database (Denmark)

Ackom, Emmanuel

2014-01-01

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...... per year. Using current bioconversion efficiency rates, the residues could potentially yield 0.12-0.32 billion liters of ethanol annually that is enough to offset 18-48% of the national consumption of gasoline. For bioelectricity generation, the same residues could provide 0.76-2.02 TW h, or 15...... of agricultural residues. The study provides policy recommendations to help encourage modern bioenergy applications from residues in Cameroon....

Indirect Climatic Effects of Major Volcanic Eruptions

Science.gov (United States)

Hofmann, D. J.

2007-05-01

The direct effects on climate, related to atmospheric emissions to the atmosphere following major volcanic eruptions, are well-known although the sparseness of such eruptions make detailed study on the range of such variations difficult. In general terms, infrared absorption by volcanic emissions to the stratosphere result in local heating early in the event when gaseous sulfur compounds exist. This early period is followed by gas to particle conversion, on a time scale of 1-2 months, promoting the formation of sulfuric acid-water droplets. Coagulation and droplet growth result in the "volcanic stratospheric aerosol layer" which is related to the predominant direct climatic effect of large eruptions, the cooling of the troposphere by backscattering of solar visible radiation to space with a recovery time scale of 1-2 years. In this paper we will discuss some of the less-known "indirect" effects of the volcanic stratospheric aerosol on climate. We label them indirect as they act on climate through intermediary atmospheric constituents. The intermediaries in the volcanic indirect climatic effect are generally atmospheric greenhouse gases or other atmospheric gases and conditions which affect greenhouse gases. For example, cooling of the troposphere following major eruptions reduces the growth rate of atmospheric carbon dioxide related to respiration by the terrestrial biosphere. In addition, redirection of part of the direct solar beam into diffuse radiation by the volcanic stratospheric aerosol stimulates plant photosynthesis, further reducing the carbon dioxide growth rate. The growth rate of the second-most important atmospheric greenhouse gas, methane, is also affected by volcanic emissions. Volcanic stratospheric aerosol particles provide surface area which catalyzes heterogeneous chemical reactions thus stimulating removal of stratospheric ozone, also a greenhouse gas. Although major droughts usually related to ENSO events have opposite effects on carbon

Volcanism Studies: Final Report for the Yucca Mountain Project

International Nuclear Information System (INIS)

Crowe, Bruce M.; Perry, Frank V.; Valentine, Greg A.; Bowker, Lynn M.

1998-01-01

This report synthesizes the results of volcanism studies conducted by scientists at the Los Alamos National Laboratory and collaborating institutions on behalf of the Department of Energy's Yucca Mountain Project. An assessment of the risk of future volcanic activity is one of many site characterization studies that must be completed to evaluate the Yucca Mountain site for potential long-term storage of high-level radioactive waste. The presence of several basaltic volcanic centers in the Yucca Mountain region of Pliocene and Quaternary age indicates that there is a finite risk of a future volcanic event occurring during the 10,000-year isolation period of a potential repository. Chapter 1 introduces the volcanism issue for the Yucca Mountain site and provides the reader with an overview of the organization, content, and significant conclusions of this report. The risk of future basaltic volcanism is the primary topic of concern including both events that intersect a potential repository and events that occur near or within the waste isolation system of a repository. Future volcanic events cannot be predicted with certainty but instead are estimated using formal methods of probabilistic volcanic hazard assessment (PVHA). Chapter 2 describes the volcanic history of the Yucca Mountain region (YMR) and emphasizes the Pliocene and Quaternary volcanic record, the interval of primary concern for volcanic risk assessment. The distribution, eruptive history, and geochronology of Plio-Quaternary basalt centers are described by individual center emphasizing the younger postcaldera basalt ( than about 7 x 10 -8 events yr -1 . Simple probability estimates are used to assess possible implications of not drilling aeromagnetic anomalies in the Amargosa Valley. The sensitivity of the disruption probability to the location of northeast boundaries of volcanic zones near the Yucca Mountain sit

Mainshock-Aftershocks Clustering Detection in Volcanic Regions

Science.gov (United States)

Garza Giron, R.; Brodsky, E. E.; Prejean, S. G.

2017-12-01

Crustal earthquakes tend to break their general Poissonean process behavior by gathering into two main kinds of seismic bursts: swarms and mainshock-aftershocks sequences. The former is commonly related to volcanic or geothermal processes whereas the latter is a characteristic feature of tectonically driven seismicity. We explore the mainshock-aftershock clustering behavior of different active volcanic regions in Japan and its comparison to non-volcanic regions. We find that aftershock production in volcanoes shows mainshock-aftershocks clustering similar to what is observed in non-volcanic areas. The ratio of volanic areas that cluster in mainshock-aftershocks sequences vs the areas that do not is comparable to the ratio of non-volcanic regions that show clustering vs the ones that do not. Furthermore, the level of production of aftershocks for most volcanic areas where clustering is present seems to be of the same order of magnitude, or slightly higher, as the median of the non-volcanic regions. An interesting example of highly aftershock-productive volcanoes emerges from the 2000 Miyakejima dike intrusion. A big seismic cluster started to build up rapidly in the south-west flank of Miyakejima to later propagate to the north-west towards the Kozushima and Niijima volcanoes. In Miyakejima the seismicity showed a swarm-like signature with a constant earthquake rate, whereas Kozushima and Niijima both had expressions of highly productive mainshock-aftershocks sequences. These findings are surprising given the alternative mechanisms available in volcanic systems for releasing deviatoric strain. We speculate that aftershock behavior might hold a relationship with the rheological properties of the rocks of each system and with the capacity of a system to accumulate or release the internal pressures caused by magmatic or hydrothermal systems.

Neogene volcanism in Gutai Mts. (Eastern Carpathains: a review

Directory of Open Access Journals (Sweden)

Marinel Kovacs

2003-04-01

Full Text Available Two types of volcanism developed in Gutâi Mts. (inner volcanic chain of Eastern Carpathians: a felsic, extensional/“back-arc” type and an intermediate, arc type. The felsic volcanism of explosive origin, consisting of caldera-related rhyolitic ignimbrites and resedimented volcaniclastics, had taken place during Early-Middle Badenian and Early Sarmatian. The intermediate volcanism, consisting of extrusive (effusive and explosive and intrusive activity, had developed during Sarmatian and Pannonian (13.4-7.0 Ma. It is represented by typical calc-alkaline series, from basalts to rhyolites. Lava flows of basaltic andesites and andesites are predominant, often emplaced in subaqueous environment. Extrusive domes, mainly composed of dacites, are associated to the andesitic volcanic structures. The intermediate volcanism, consisting of extrusive (effusive and explosive and intrusive activity, had developed during Sarmatian and Pannonian (13.4-7.0 Ma. It is represented by typical calc-alkaline series, from basalts to rhyolites. Lava flows of basaltic andesites and andesites are predominant, often emplaced in subaqueous environment. Extrusive domes, mainly composed of dacites, are associated to the andesitic volcanic structures. The geochemical study on the volcanic rocks shows the calc-alkaline character of both felsic and intermediate volcanism and typical subduction zones geochemical signatures for the intermediate one. The felsic volcanism shows affinities with subduction-related rocks as well. The main petrogenetic process in Gutâi Mts. was crustal assimilation, strongly constrained by trace element and isotope geochemistry.

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

OpenAIRE

Kamgang, Basile; Nchoutpouen, Elysée; Simard, Frédéric; Paupy, Christophe

2012-01-01

Abstract Background The invasive mosquito Aedes albopictus is often considered a poor vector of human pathogens, owing to its catholic feeding behavior. However, it was recently incriminated as a major vector in several Chikungunya epidemics, outside of its native range. Here we assessed two key elements of feeding behavior by Ae. albopictus females in Yaoundé, Cameroon, Central Africa. Host preference was explored and the human-biting activity of females was monitored over 24 h to determine ...

Bovine trypanosomosis in north province of cameroon

International Nuclear Information System (INIS)

Ndamkou, C.N.; Nchare, A.

1997-01-01

The results of the examination of 2959 bovine blood samples collected from four divisions of North Province of Cameroon showed a prevalence of 1.72 for T. brucei, 0.98 for T. congolense and 4.03 for T. vivax using parasitological techniques, such as the buffy coat technique (BCT) and the microhaematrocrit centrifugation technique (MHCT). Prevalence rates in tsetse infested areas were higher than in tsetse free areas for T. brucei and T. congolense, but not for T. vivax. The Antigen ELISA was used to detect trypanosomal antigens in serum samples of a subset of the same animals. By using the Ag-ELISA many more animals were detected positive for T. brucei and T. vivax, but not for T. congolense, than when just the two parasitological techniques were used. As a matter of fact 90% of the T. brucei infections were detected by the Ag-ELISA and 10% by using either the BCT or the MHCT. (author).6 refs, 5 figs, 6 tabs

Bovine trypanosomosis in north province of cameroon

Energy Technology Data Exchange (ETDEWEB)

Ndamkou, C N; Nchare, A [Laboratoire National Veterinaire de Bokle (LANAVET), Garoua (Cameroon)

1997-02-01

The results of the examination of 2959 bovine blood samples collected from four divisions of North Province of Cameroon showed a prevalence of 1.72 for T. brucei, 0.98 for T. congolense and 4.03 for T. vivax using parasitological techniques, such as the buffy coat technique (BCT) and the microhaematrocrit centrifugation technique (MHCT). Prevalence rates in tsetse infested areas were higher than in tsetse free areas for T. brucei and T. congolense, but not for T. vivax. The Antigen ELISA was used to detect trypanosomal antigens in serum samples of a subset of the same animals. By using the Ag-ELISA many more animals were detected positive for T. brucei and T. vivax, but not for T. congolense, than when just the two parasitological techniques were used. As a matter of fact 90% of the T. brucei infections were detected by the Ag-ELISA and 10% by using either the BCT or the MHCT. (author).6 refs, 5 figs, 6 tabs.

Livelihood opportunities amongst adults with and without disabilities in Cameroon and India: A case control study.

Science.gov (United States)

Mactaggart, Islay; Banks, Lena Morgon; Kuper, Hannah; Murthy, G V S; Sagar, Jayanthi; Oye, Joseph; Polack, Sarah

2018-01-01

Proven links between disability and poverty suggest that development programmes and policies that are not disability-inclusive will leave persons with disabilities behind. Despite this, there is limited quantitative evidence on livelihood opportunities amongst adults with disabilities in Low and Middle Income Countries. This study adds to the limited evidence base, contributing data from one African and one Asian Setting. We undertook a population-based case-control study of adults (18+) with and without disabilities in North-West Cameroon and in Telangana State, India. We found that adults with disabilities were five times less likely to be working compared to age-sex matched controls in both settings. Amongst adults with disabilities, current age, marital status and disability type were key predictors of working. Inclusive programmes are therefore needed to provide adequate opportunities to participate in livelihood prospects for adults with disabilities in Cameroon and India, on an equal basis as others. These findings are of crucial importance at this stage of the Sustainable Development Agenda, to ensure that the mandate of inclusive development is achieved.

Electricity Self-Generation Costs for Industrial Companies in Cameroon

Directory of Open Access Journals (Sweden)

Diboma Benjamin Salomon

2010-07-01

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

Petrology and geochronology of metamorphosed volcanic rocks and a middle Cretaceous volcanic neck in the east-central Sierra Nevada, California.

Science.gov (United States)

Kistler, R.W.; Swanson, S.E.

1981-01-01

Metamorphosed Mesozoic volcanic rocks from the E-central Sierra Nevada range in composition from basalt to rhyolite and have ages, based on whole rock Rb-Sr and U-Pb zircon dating, of about 237- 224, 185, 163, 134, and 100Ma. The major plutons of the batholith in this area are of Triassic (215-200Ma) and Cretaceous (94-80Ma) ages. Initial 87Sr/86Sr values for the metamorphosed volcanic rocks of the area are in the range from 0.7042 to 0.7058 and are generally different from the values for the surrounding batholithic rocks (0.7056-0.7066). A circular, zoned granitic pluton, with an outcrop area of 2.5km2, similar in appearance to a ring dike complex, was apparently a conduit for some or possibly all of the middle-Cretaceous metamorphosed volcanic rocks exposed about 5km to the S in the western part of the Ritter Range. Samples from the metamorphosed volcanic rocks and the pluton yield a Rb/Sr whole rock isochron age of 99.9+ or -2.2Ma with an intitial 87Sr/86Sr of 0.7048+ or -0.00001. Major element variation diagrams of the pluton and volcanic rocks define coincident compositional trends. The ages of volcanic events relative to the ages of the major intrusive epochs and the major element and isotopic compositions of the volcanic rocks relative to the major plutons indicate that the volcanic rocks are not simply or directly related to the major plutons in the Sierra Nevada. -from Authors

Volcanic Characteristics of Kueishantao in Northeast Taiwan and Their Implications

Directory of Open Access Journals (Sweden)

Ching-Lung Chiu

2010-01-01

Full Text Available Kueishantao (KST is a small offshore volcanic island located at the southernmost part of the Okinawa Trough. In this study, we conducted a detailed mapping incorporating the new high resolution LiDAR DTM laser scanning device to accurately construct a volcanic sequence. A new 1/5000 geological map was established. One primary volcanic cone, composed of layers of both lava flows and pyroclastic rocks constituted the major edifice of KST. The other minor volcanic cone, which consists of volcanic lapillis and blocks, is seated to the east of the main cone. The escarped and nearly straight coast in the southern part of the KST indicates that the volcano suffered a large post-volcanic edifice collapse erasing nearly one half of the volume of both volcanic cones. The increase in the abundance of the xenoliths of sedimentary rocks from the lower to the upper part of the volcanic sequence indicates that the formation of volcanic rocks of the KST involved an intensification of crustal contamination. The possibility of volcanic eruption can not be excluded in the future based on the present thermolu¬minescene age data of 7 ka. The associated eruptive ash fall and tsunami induced by the further collapse of the KST volcanic edifice might have great influence to the adjacent inland. Thus, long-term monitoring of volcanic activities around KST should be required for future hazard assessments.

The Valle de Bravo Volcanic Field. A monogenetic field in the central front of the Mexican Volcanic Belt

Science.gov (United States)

Aguirre-Diaz, G. J.; Jaimes-Viera, M. D.; Nieto-Obreg¢n, J.; Lozano-Santacruz, R.

2003-12-01

The Valle de Bravo volcanic field, VBVF, is located in the central-southern front of the Mexican Volcanic Belt just to the southwest of Nevado de Toluca volcano. The VBVF covers 3,703 square Km and includes at least 122 cinder cones, 1 shield volcano, several domes, and the 2 volcanic complexes of Zitacuaro and Villa de Allende. Morphometric parameters calibrated with isotopic ages of the volcanic products indicate four groups or units for the VBVF, Pliocene domes and lava flows, undifferentiated Pleistocene lava flows,> 40 Ka cones and lavas, 40 to 25 Ka cones and lavas, 25 to 10 Ka cones and lavas, and < 10 Ka cones and lavas. Whole-rock chemistry shows that all products of the VBVF range from basaltic andesites to dacites. No basalts were found, in spite of many units are olivine-rich and large some with large weight percent contents of MgO, 1 to 9. There is the possibility that some or all of the olivines in some samples could be xenocrysts. Some andesites are high in Sr, 1000 to 1800 ppm, that correlates with relatively high values of Ba, Cr, Ni, Cu, CaO and MgO. Y and Nb have the typical low values for orogenic rocks. The only shield volcano of the VBVF has a base of 9 Km, and its composition is practically the average composition of the whole field. Stratigraphycally, it is one of the earlier events of the VBVF. Compared with other volcanic fields of the Mexican Volcanic Belt, it lacks basalts and alkalic rocks. All volcanism of this field is calcalkaline

Mapping the geographical distribution of podoconiosis in Cameroon using parasitological, serological, and clinical evidence to exclude other causes of lymphedema.

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Kebede Deribe

2018-01-01

Full Text Available Podoconiosis is a non-filarial elephantiasis, which causes massive swelling of the lower legs. It was identified as a neglected tropical disease by WHO in 2011. Understanding of the geographical distribution of the disease is incomplete. As part of a global mapping of podoconiosis, this study was conducted in Cameroon to map the distribution of the disease. This mapping work will help to generate data on the geographical distribution of podoconiosis in Cameroon and contribute to the global atlas of podoconiosis.We used a multi-stage sampling design with stratification of the country by environmental risk of podoconiosis. We sampled 76 villages from 40 health districts from the ten Regions of Cameroon. All individuals of 15-years old or older in the village were surveyed house-to-house and screened for lymphedema. A clinical algorithm was used to reliably diagnose podoconiosis, excluding filarial-associated lymphedema. Individuals with lymphoedema were tested for circulating Wuchereria bancrofti antigen and specific IgG4 using the Alere Filariasis Test Strips (FTS test and the Standard Diagnostics (SD BIOLINE lymphatic filariasis IgG4 test (Wb123 respectively, in addition to thick blood films. Presence of DNA specific to W. bancrofti was checked on night blood using a qPCR technique.Overall, 10,178 individuals from 4,603 households participated in the study. In total, 83 individuals with lymphedema were identified. Of the 83 individuals with lymphedema, two were found to be FTS positive and all were negative using the Wb123 test. No microfilaria of W. bancrofti were found in the night blood of any individual with clinical lymphedema. None were found to be positive for W. bancrofti using qPCR. Of the two FTS positive cases, one was positive for Mansonella perstans DNA, while the other harbored Loa loa microfilaria. Overall, 52 people with podoconiosis were identified after applying the clinical algorithm. The overall prevalence of podoconiosis was

Assessment of the atmospheric impact of volcanic eruptions

Science.gov (United States)

Sigurdsson, H.

1988-01-01

The dominant global impact of volcanic activity is likely to be related to the effects of volcanic gases on the Earth's atmosphere. Volcanic gas emissions from individual volcanic arc eruptions are likely to cause increases in the stratospheric optical depth that result in surface landmass temperature decline of 2 to 3 K for less than a decade. Trachytic and intermediate magmas are much more effective in this regard than high-silica magmas, and may also lead to extensive ozone depletion due to effect of halogens and magmatic water. Given the assumed relationship between arc volcanism and subduction rate, and the relatively small variation in global spreading rates in the geologic record, it is unlikely that the rates of arc volcanism have varied greatly during the Cenozoic. Hotspot related basaltic fissure eruptions in the subaerial environment have a higher mass yield of sulfur, but lofting of the valcanic aerosol to levels above the tropopause is required for a climate impact. High-latitude events, such as the Laki 1783 eruption can easily penetrate the tropopause and enter the stratosphere, but formation of a stratospheric volcanic aerosol form low-latitude effusive basaltic eruptions is problematical, due to the elevated low-latitude tropopause. Due to the high sulfur content of hotspot-derived basaltic magmas, their very high mass eruption rates and the episodic behavior, hotspots must be regarded as potentially major modifiers of Earth's climate through the action of their volcanic volatiles on the chemistry and physics of the atmosphere.

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

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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.

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

NARCIS (Netherlands)

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

2016-01-01

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

A Volcanic Hydrogen Habitable Zone

International Nuclear Information System (INIS)

Ramirez, Ramses M.; Kaltenegger, Lisa

2017-01-01

The classical habitable zone (HZ) is the circular region around a star in which liquid water could exist on the surface of a rocky planet. The outer edge of the traditional N_2–CO_2–H_2O HZ extends out to nearly ∼1.7 au in our solar system, beyond which condensation and scattering by CO_2 outstrips its greenhouse capacity. Here, we show that volcanic outgassing of atmospheric H_2 can extend the outer edge of the HZ to ∼2.4 au in our solar system. This wider volcanic-hydrogen HZ (N_2–CO_2–H_2O–H_2) can be sustained as long as volcanic H_2 output offsets its escape from the top of the atmosphere. We use a single-column radiative-convective climate model to compute the HZ limits of this volcanic hydrogen HZ for hydrogen concentrations between 1% and 50%, assuming diffusion-limited atmospheric escape. At a hydrogen concentration of 50%, the effective stellar flux required to support the outer edge decreases by ∼35%–60% for M–A stars. The corresponding orbital distances increase by ∼30%–60%. The inner edge of this HZ only moves out ∼0.1%–4% relative to the classical HZ because H_2 warming is reduced in dense H_2O atmospheres. The atmospheric scale heights of such volcanic H_2 atmospheres near the outer edge of the HZ also increase, facilitating remote detection of atmospheric signatures.

A Volcanic Hydrogen Habitable Zone

Energy Technology Data Exchange (ETDEWEB)

Ramirez, Ramses M.; Kaltenegger, Lisa, E-mail: rmr277@cornell.edu [Carl Sagan Institute, Cornell University, Ithaca, NY (United States)

2017-03-01

The classical habitable zone (HZ) is the circular region around a star in which liquid water could exist on the surface of a rocky planet. The outer edge of the traditional N{sub 2}–CO{sub 2}–H{sub 2}O HZ extends out to nearly ∼1.7 au in our solar system, beyond which condensation and scattering by CO{sub 2} outstrips its greenhouse capacity. Here, we show that volcanic outgassing of atmospheric H{sub 2} can extend the outer edge of the HZ to ∼2.4 au in our solar system. This wider volcanic-hydrogen HZ (N{sub 2}–CO{sub 2}–H{sub 2}O–H{sub 2}) can be sustained as long as volcanic H{sub 2} output offsets its escape from the top of the atmosphere. We use a single-column radiative-convective climate model to compute the HZ limits of this volcanic hydrogen HZ for hydrogen concentrations between 1% and 50%, assuming diffusion-limited atmospheric escape. At a hydrogen concentration of 50%, the effective stellar flux required to support the outer edge decreases by ∼35%–60% for M–A stars. The corresponding orbital distances increase by ∼30%–60%. The inner edge of this HZ only moves out ∼0.1%–4% relative to the classical HZ because H{sub 2} warming is reduced in dense H{sub 2}O atmospheres. The atmospheric scale heights of such volcanic H{sub 2} atmospheres near the outer edge of the HZ also increase, facilitating remote detection of atmospheric signatures.

Large-scale volcanism associated with coronae on Venus

Science.gov (United States)

Roberts, K. Magee; Head, James W.

1993-01-01

The formation and evolution of coronae on Venus are thought to be the result of mantle upwellings against the crust and lithosphere and subsequent gravitational relaxation. A variety of other features on Venus have been linked to processes associated with mantle upwelling, including shield volcanoes on large regional rises such as Beta, Atla and Western Eistla Regiones and extensive flow fields such as Mylitta and Kaiwan Fluctus near the Lada Terra/Lavinia Planitia boundary. Of these features, coronae appear to possess the smallest amounts of associated volcanism, although volcanism associated with coronae has only been qualitatively examined. An initial survey of coronae based on recent Magellan data indicated that only 9 percent of all coronae are associated with substantial amounts of volcanism, including interior calderas or edifices greater than 50 km in diameter and extensive, exterior radial flow fields. Sixty-eight percent of all coronae were found to have lesser amounts of volcanism, including interior flooding and associated volcanic domes and small shields; the remaining coronae were considered deficient in associated volcanism. It is possible that coronae are related to mantle plumes or diapirs that are lower in volume or in partial melt than those associated with the large shields or flow fields. Regional tectonics or variations in local crustal and thermal structure may also be significant in determining the amount of volcanism produced from an upwelling. It is also possible that flow fields associated with some coronae are sheet-like in nature and may not be readily identified. If coronae are associated with volcanic flow fields, then they may be a significant contributor to plains formation on Venus, as they number over 300 and are widely distributed across the planet. As a continuation of our analysis of large-scale volcanism on Venus, we have reexamined the known population of coronae and assessed quantitatively the scale of volcanism associated

The exploitation of "Exploitation" in the tenofovir prep trial in Cameroon: Lessons learned from media coverage of an HIV prevention trial.

Science.gov (United States)

Mack, Natasha; Robinson, Elizabeth T; MacQueen, Kathleen M; Moffett, Jill; Johnson, Laura M

2010-06-01

media coverage influences how clinical trials are perceived internationally and in communities where trials occur, affecting recruitment, retention, and political support for research. We conducted a discourse analysis of news coverage from 2004-2005 of a trial in Cameroon on oral PrEP for HIV prevention, to identify messages, communication techniques, and sources of messages that were amplified via media. We identified two parallel discourses: one on ethical concerns about the Cameroon trial, and a second, more general "science exploitation" discourse concerned with the potential for trials with vulnerable participant populations to be conducted unethically, benefiting only wealthy populations. Researchers should overtly address exploitation as an integral, ongoing component of research, particularly where historical or cultural conditions set the stage for controversy to emerge.

Submarine Volcanic Eruptions and Potential Analogs for Venus

Science.gov (United States)

Wilson, L.; Mouginismark, P. J.; Fryer, P.; Gaddis, L. R.

1985-01-01

As part of an analysis program to better understand the diversity of volcanic processes on the terrestrial planets, an investigation of the volcanic landforms which exist on the Earth's ocean floor was initiated. In part, this analysis is focused toward gaining a better understanding of submarine volcanic landforms in their own right, but also it is hoped that these features may show similarities to volcanic landforms on Venus, due to the high ambient water (Earth) and atmospheric (Venus) pressures. A series of numerical modelling experiments was performed to investigate the relative importance of such attributes as water pressure and temperature on the eruption process, and to determine the rate of cooling and emplacement of lava flows in the submarine environment. Investigations to date show that the confining water pressure and the buoyancy effects of the surrounding water significantly affect the styles of volcanism on the ocean floor. In the case of Venusian volcanism, confining pressures will not be as great as that found at the ocean's abyssal plains, but nevertheless the general trend toward reducing magma vesiculation will hold true for Venus as well as the ocean floor. Furthermore, other analogs may also be found between submarine volcanism and Venusian activity.

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

Directory of Open Access Journals (Sweden)

Lauren Q. Sneyd

2013-11-01

Full Text Available 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/traditional foods are physically available in Cameroonian cities most of the time, including fruits, vegetables, spices, and insects. Cameroonians spend considerable sums of their food budget on wild foods. However, low wages and the high cost of city living constrain the social and economic access most people have to these foods. The data also suggest that imports of non-traditional staple foods, such as low cost rice, have increasingly priced potentially more nutritious or safe traditional local foods out of markets after the 2008 food price crisis. As a result, diets are changing in Cameroon as the resource-constrained population continues to resort to the coping strategy of eating cheaper imported foods such as refined rice or to eating less frequently. Cameroon’s nutrition transition continues to be driven by need and not necessarily by the preferences of Cameroonian consumers. The implications of this reality for sustainability are troubling.

Constructional Volcanic Edifices on Mercury: Candidates and Hypotheses of Formation

Science.gov (United States)

Wright, Jack; Rothery, David A.; Balme, Matthew R.; Conway, Susan J.

2018-04-01

Mercury, a planet with a predominantly volcanic crust, has perplexingly few, if any, constructional volcanic edifices, despite their common occurrence on other solar system bodies with volcanic histories. Using image and topographical data from the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft, we describe two small (Earth and the Moon. Though we cannot definitively conclude that these landforms are volcanic, the paucity of constructional volcanic edifices on Mercury is intriguing in itself. We suggest that this lack is because volcanic eruptions with sufficiently low eruption volumes, rates, and flow lengths, suitable for edifice construction, were highly spatiotemporally restricted during Mercury's geological history. We suggest that volcanic edifices may preferentially occur in association with late-stage, postimpact effusive volcanic deposits. The European Space Agency/Japan Aerospace Exploration Agency BepiColombo mission to Mercury will be able to investigate further our candidate volcanic edifices; search for other, as-yet unrecognized edifices beneath the detection limits of MESSENGER data; and test our hypothesis that edifice construction is favored by late-stage, low-volume effusive eruptions.

Age of the Auckland Volcanic Field

International Nuclear Information System (INIS)

Lindsay, J.; Leonard, G.S.

2009-01-01

In 2008 a multi-disciplinary research programme was launched, a GNS Science-University of Auckland collaboration with the aim of DEtermining VOlcanic Risk in Auckland (DEVORA). A major aspiration of DEVORA is development of a probabilistic hazard model for the Auckland Volcanic Field (AVF). This will be achieved by investigating past eruption magnitude-frequency relationships and comparing these with similar data from analogous volcanic fields. A key data set underpinning this is an age database for the AVF. To this end a comprehensive dating campaign is planned as part of DEVORA. This report, Age of the Auckland Volcanic Field, is a synthesis of all currently available age data for the AVF. It represents one of several reports carried out as part of the 'synthesis' phase of DEVORA, whereby existing data from all previous work is collated and summarised, so that gaps in current knowledge can be identified and addressed. (author). 60 refs., 7 figs., 31 tabs.

Sediment-infill volcanic breccia from the Neoarchean Shimoga greenstone terrane, western Dharwar Craton: Implications on pyroclastic volcanism and sedimentation in an active continental margin

Science.gov (United States)

Manikyamba, C.; Saha, Abhishek; Ganguly, Sohini; Santosh, M.; Lingadevaru, M.; Rajanikanta Singh, M.; Subba Rao, D. V.

2014-12-01

We report sediment-infill volcanic breccia from the Neoarchean Shimoga greenstone belt of western Dharwar Craton which is associated with rhyolites, chlorite schists and pyroclastic rocks. The pyroclastic rocks of Yalavadahalli area of Shimoga greenstone belt host volcanogenic Pb-Cu-Zn mineralization. The sediment-infill volcanic breccia is clast-supported and comprises angular to sub-angular felsic volcanic clasts embedded in a dolomitic matrix that infilled the spaces in between the framework of volcanic clasts. The volcanic clasts are essentially composed of alkali feldspar and quartz with accessory biotite and opaques. These clasts have geochemical characteristics consistent with that of the associated potassic rhyolites from Daginkatte Formation. The rare earth elements (REE) and high field strength element (HFSE) compositions of the sediment-infill volcanic breccia and associated mafic and felsic volcanic rocks suggest an active continental margin setting for their generation. Origin, transport and deposition of these rhyolitic clasts and their aggregation with infiltrated carbonate sediments may be attributed to pyroclastic volcanism, short distance transportation of felsic volcanic clasts and their deposition in a shallow marine shelf in an active continental margin tectonic setting where the rhyolitic clasts were cemented by carbonate material. This unique rock type, marked by close association of pyroclastic volcanic rocks and shallow marine shelf sediments, suggest shorter distance between the ridge and shelf in the Neoarchean plate tectonic scenario.

Volcanic Supersites as cross-disciplinary laboratories

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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

Lidar detection of carbon dioxide in volcanic plumes

Science.gov (United States)

Fiorani, Luca; Santoro, Simone; Parracino, Stefano; Maio, Giovanni; Del Franco, Mario; Aiuppa, Alessandro

2015-06-01

Volcanic gases give information on magmatic processes. In particular, anomalous releases of carbon dioxide precede volcanic eruptions. Up to now, this gas has been measured in volcanic plumes with conventional measurements that imply the severe risks of local sampling and can last many hours. For these reasons and for the great advantages of laser sensing, the thorough development of volcanic lidar has been undertaken at the Diagnostics and Metrology Laboratory (UTAPRAD-DIM) of the Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA). In fact, lidar profiling allows one to scan remotely volcanic plumes in a fast and continuous way, and with high spatial and temporal resolution. Two differential absorption lidar instruments will be presented in this paper: BILLI (BrIdge voLcanic LIdar), based on injection seeded Nd:YAG laser, double grating dye laser, difference frequency mixing (DFM) and optical parametric amplifier (OPA), and VULLI (VULcamed Lidar), based on injection seeded Nd:YAG laser and optical parametric oscillator (OPO). The first one is funded by the ERC (European Research Council) project BRIDGE and the second one by the ERDF (European Regional Development Fund) project VULCAMED. While VULLI has not yet been tested in a volcanic site, BILLI scanned the gas emitted by Pozzuoli Solfatara (Campi Flegrei volcanic area, Naples, Italy) during a field campaign carried out from 13 to 17 October 2014. Carbon dioxide concentration maps were retrieved remotely in few minutes in the crater area. Lidar measurements were in good agreement with well-established techniques, based on different operating principles. To our knowledge, it is the first time that carbon dioxide in a volcanic plume is retrieved by lidar, representing the first direct measurement of this kind ever performed on an active volcano and showing the high potential of laser remote sensing in geophysical research.

Topographic stress and catastrophic collapse of volcanic islands

Science.gov (United States)

Moon, S.; Perron, J. T.; Martel, S. J.

2017-12-01

Flank collapse of volcanic islands can devastate coastal environments and potentially induce tsunamis. Previous studies have suggested that factors such as volcanic eruption events, gravitational spreading, the reduction of material strength due to hydrothermal alteration, steep coastal cliffs, or sea level change may contribute to slope instability and induce catastrophic collapse of volcanic flanks. In this study, we examine the potential influence of three-dimensional topographic stress perturbations on flank collapses of volcanic islands. Using a three-dimensional boundary element model, we calculate subsurface stress fields for the Canary and Hawaiian islands to compare the effects of stratovolcano and shield volcano shapes on topographic stresses. Our model accounts for gravitational stresses from the actual shapes of volcanic islands, ambient stress in the underlying plate, and the influence of pore water pressure. We quantify the potential for slope failure of volcanic flanks using a combined model of three-dimensional topographic stress and slope stability. The results of our analysis show that subsurface stress fields vary substantially depending on the shapes of volcanoes, and can influence the size and spatial distribution of flank failures.

Lahar—River of volcanic mud and debris

Science.gov (United States)

Major, Jon J.; Pierson, Thomas C.; Vallance, James W.

2018-05-09

Lahar, an Indonesian word for volcanic mudflow, is a mixture of water, mud, and volcanic rock flowing swiftly along a channel draining a volcano. Lahars can form during or after eruptions, or even during periods of inactivity. They are among the greatest threats volcanoes pose to people and property. Lahars can occur with little to no warning, and may travel great distances at high speeds, destroying or burying everything in their paths.Lahars form in many ways. They commonly occur when eruptions melt snow and ice on snow-clad volcanoes; when rains fall on steep slopes covered with fresh volcanic ash; when crater lakes, volcano glaciers or lakes dammed by volcanic debris suddenly release water; and when volcanic landslides evolve into flowing debris. Lahars are especially likely to occur at erupting or recently active volcanoes.Because lahars are so hazardous, U.S. Geological Survey scientists pay them close attention. They study lahar deposits and limits of inundation, model flow behavior, develop lahar-hazard maps, and work with community leaders and governmental authorities to help them understand and minimize the risks of devastating lahars.

Volcanic styles at Alba Patera, Mars: implications of lava flow morphology to the volcanic history

International Nuclear Information System (INIS)

Schneeberger, D.M.; Pieri, D.C.

1988-01-01

Alba Patera presents styles of volcanism that are unique to Mars. Its very low profile, large areal extent, unusually long and voluminous lava flows, and circumferential graben make it among Mars' most interesting volcanic features. Clues to Alba's volcanic history are preserved in its morphology and stratigraphy. Understanding the relationship of lava flow morphology to emplacement processes should enable estimates of viscosity, effusion rate, and gross composition to be made. Lava flows, with dimensions considered enormous by terrestrial standards, account for a major portion of the exposed surface of Alba Patera. These flows exhibit a range of morphologies. While most previous works have focused on the planimetric characteristics, attention was drawn to the important morphological attributes, paying particular attention to what the features suggest about the emplacement process

Insights into chameleons of the genus Trioceros (Squamata: Chamaeleonidae) in Cameroon, with the resurrection of Chamaleon serratus Mertens, 1922

Czech Academy of Sciences Publication Activity Database

Barej, M. F.; Ineich, I.; Gvoždík, Václav; Lhermitte-Vallarino, N.; Gonwouo, N.L.; Le Breton, M.; Bott, U.; Schmitz, A.

2010-01-01

Roč. 57, č. 2 (2010), s. 211-229 ISSN 2190-7307 R&D Projects: GA MŠk LC06073 Institutional research plan: CEZ:AV0Z50450515 Keywords : Chameleon serratus * Cameroon * insights Subject RIV: EG - Zoology

Imaging volcanic CO2 and SO2

Science.gov (United States)

Gabrieli, A.; Wright, R.; Lucey, P. G.; Porter, J. N.

2017-12-01

Detecting and quantifying volcanic carbon dioxide (CO2) and sulfur dioxide (SO2) emissions is of relevance to volcanologists. Changes in the amount and composition of gases that volcanoes emit are related to subsurface magma movements and the probability of eruptions. Volcanic gases and related acidic aerosols are also an important atmospheric pollution source that create environmental health hazards for people, animals, plants, and infrastructures. For these reasons, it is important to measure emissions from volcanic plumes during both day and night. We present image measurements of the volcanic plume at Kīlauea volcano, HI, and flux derivation, using a newly developed 8-14 um hyperspectral imaging spectrometer, the Thermal Hyperspectral Imager (THI). THI is capable of acquiring images of the scene it views from which spectra can be derived from each pixel. Each spectrum contains 50 wavelength samples between 8 and 14 um where CO2 and SO2 volcanic gases have diagnostic absorption/emission features respectively at 8.6 and 14 um. Plume radiance measurements were carried out both during the day and the night by using both the lava lake in the Halema'uma'u crater as a hot source and the sky as a cold background to detect respectively the spectral signatures of volcanic CO2 and SO2 gases. CO2 and SO2 path-concentrations were then obtained from the spectral radiance measurements using a new Partial Least Squares Regression (PLSR)-based inversion algorithm, which was developed as part of this project. Volcanic emission fluxes were determined by combining the path measurements with wind observations, derived directly from the images. Several hours long time-series of volcanic emission fluxes will be presented and the SO2 conversion rates into aerosols will be discussed. The new imaging and inversion technique, discussed here, are novel allowing for continuous CO2 and SO2 plume mapping during both day and night.

Inside the volcanic boiler room: knowledge exchange among stakeholders of volcanic unrest

Science.gov (United States)

Gottsmann, Joachim; Christie, Ryerson; Bretton, Richard

2014-05-01

The knowledge of the causative links between subsurface processes, resulting monitoring signals and imminent eruption is incomplete. As a consequence, hazard assessment and risk mitigation strategies are subject to uncertainty. Discussion of unrest and pre-eruptive scenarios with uncertain outcomes are central during the discourse between a variety of stakeholders in volcanic unrest including scientists, emergency managers, policy makers and the public. Drawing from research within the EC FP7 VUELCO project, we argue that knowledge exchange amongst the different stakeholders of volcanic unrest evolves along three dimensions: 1) the identification of knowledge holders (including local communities) and their needs and expectations, 2) vehicles of communication and 3) trust. In preparing products that feed into risk assessment and management, scientists need to ensure that their deliverables are timely, accurate, clear, understandable and cater to the expectations of emergency managers. The means and content of communication amongst stakeholders need to be defined and adhered to. Finally, efficient and effective interaction between stakeholders is ideally based on mutual trust between those that generate knowledge and those that receive knowledge. For scientists, this entails contextualising volcanic hazard and risk in the framework of environmental and social values. Periods of volcanic quiescence are ideally suited to test established protocols of engagement between stakeholders in preparation for crises situations. The different roles of stakeholders and associated rules of engagement can be scrutinised and reviewed in antecessum rather than ad-hoc during a crisis situation to avoid issues related to distrust, loss of credibility and overall poor risk management. We will discuss these themes drawing from exploitation of research results from Mexico and Ecuador.

Ages of plains volcanism on Mars

Science.gov (United States)

Hauber, Ernst; Jagert, Felix; Broz, Petr

2010-05-01

Plain-style volcanism [1] is widespread in the Tharsis and Elysium volcanic provinces on Mars, [2,3]. Detailed images and topographic data reveal the morphology and topography of clusters of low shields and associated lava flows. The landforms of plains volcanism on Mars have all well-known terrestrial analogues in basaltic volcanic regions, such as Hawaii, Iceland, and in particular the Snake River Plains [4]. The very gentle flank slopes (J. (1981) Icarus, 45, 586-601. [3] Hodges C.A. and Moore H.J. (1994) Atlas of volcanic features on Mars: USGS Prof. Paper 1534, 194 p. [4] Hauber E. et al. (2009) J. Volcanol. Geotherm. Res. 185, 69-95. [5] Wilson L. et al. (2009) J. Volcanol. Geotherm. Res. 185, 28-46. [6] Vaucher, J. et al. (2009) Icarus 204, 418-442. [7] Baratoux D. et al. (2009) J. Volcanol. Geotherm. Res. 185, 47-68. [8] Bleacher J.E. et al. (2009) J. Volcanol. Geotherm. Res. 185, 96-102. [9] Ivanov B.A. (2001) Space Sci. Rev. 96, 87-104. [10] Hartmann W.H. and Neukum G. (2001) Space Sci. Rev. 96, 165-194 [11] Kneissl T. et al. (2010) LPS XVI, submitted. [12] Michael, G.G. and Neukum G. (2010) Earth Planet. Sci. Lett., in press. . [13] Malin M.C. et al. (2007) JGR 112, E05S04, doi: 10.1029/2006JE002808.

Field-trip guide to mafic volcanism of the Cascade Range in Central Oregon—A volcanic, tectonic, hydrologic, and geomorphic journey

Science.gov (United States)

Deligne, Natalia I.; Mckay, Daniele; Conrey, Richard M.; Grant, Gordon E.; Johnson, Emily R.; O'Connor, Jim; Sweeney, Kristin

2017-08-16

The Cascade Range in central Oregon has been shaped by tectonics, volcanism, and hydrology, as well as geomorphic forces that include glaciations. As a result of the rich interplay between these forces, mafic volcanism here can have surprising manifestations, which include relatively large tephra footprints and extensive lava flows, as well as water shortages, transportation and agricultural disruption, and forest fires. Although the focus of this multidisciplinary field trip will be on mafic volcanism, we will also look at the hydrology, geomorphology, and ecology of the area, and we will examine how these elements both influence and are influenced by mafic volcanism. We will see mafic volcanic rocks at the Sand Mountain volcanic field and in the Santiam Pass area, at McKenzie Pass, and in the southern Bend region. In addition, this field trip will occur during a total solar eclipse, the first one visible in the United States in more than 25 years (and the first seen in the conterminous United States in more than 37 years).The Cascade Range is the result of subduction of the Juan de Fuca plate underneath the North American plate. This north-south-trending volcanic mountain range is immediately downwind of the Pacific Ocean, a huge source of moisture. As moisture is blown eastward from the Pacific on prevailing winds, it encounters the Cascade Range in Oregon, and the resulting orographic lift and corresponding rain shadow is one of the strongest precipitation gradients in the conterminous United States. We will see how the products of the volcanoes in the central Oregon Cascades have had a profound influence on groundwater flow and, thus, on the distribution of Pacific moisture. We will also see the influence that mafic volcanism has had on landscape evolution, vegetation development, and general hydrology.

Motorcycle injury among secondary school students in the Tiko municipality, Cameroon.

Science.gov (United States)

Nyagwui, Asonganyi Edwin; Fredinah, Namatovu; Che, Longho Bernard; Yulia, Blomstedt

2016-01-01

Injury from motorcycle is a considerable cause of disability and death in the world and especially in low and middle-income countries; it is one of the most serious public health problems. In Cameroon, motorcycle is commonly used for transportation particularly among students. The aim of this paper is to study the risk-factors of the motorcycle-related accidents and injuries among secondary school students' in the Tiko municipality, Cameroon. A cross sectional study was conducted in January 2012 on 391 students age 16-24 from public and private schools in the Tiko Municipality. Logistic regression was used to estimate the association between risk factors and injuries. A closed-ended and few open-ended questionnaire was used to collect data. The study showed that over 70% of students used motorcycles always or often. Few had undergone any formal training for driving a motorcycle. The vast majority reported not wearing protective gear while driving or riding a motorcycle. Usage of protective gear was particularly low among girls. Over 16% reported using a motorbike always or occasionally under the influence of alcohol or drugs. Over 58% of respondents reported having an accident and over 35% were injured when driving or riding a motorcycle. Those who lived at the Tiko-Douala road have three times higher probability to sustain accidents and injuries than students residing elsewhere (OR 3.19 (1.20-8.46). It is deeply alarming that every second respondent in the study reported having been in an accident and every third motorcycle user was somehow injured. We therefore call for an immediate attention and a deeper investigation into the highlighted situation, particularly at Tiko-Douala road.

Long term volcanic hazard analysis in the Canary Islands

Science.gov (United States)

Becerril, L.; Galindo, I.; Laín, L.; Llorente, M.; Mancebo, M. J.

2009-04-01

Historic volcanism in Spain is restricted to the Canary Islands, a volcanic archipelago formed by seven volcanic islands. Several historic eruptions have been registered in the last five hundred years. However, and despite the huge amount of citizens and tourist in the archipelago, only a few volcanic hazard studies have been carried out. These studies are mainly focused in the developing of hazard maps in Lanzarote and Tenerife islands, especially for land use planning. The main handicap for these studies in the Canary Islands is the lack of well reported historical eruptions, but also the lack of data such as geochronological, geochemical or structural. In recent years, the use of Geographical Information Systems (GIS) and the improvement in the volcanic processes modelling has provided an important tool for volcanic hazard assessment. Although this sophisticated programs are really useful they need to be fed by a huge amount of data that sometimes, such in the case of the Canary Islands, are not available. For this reason, the Spanish Geological Survey (IGME) is developing a complete geo-referenced database for long term volcanic analysis in the Canary Islands. The Canarian Volcanic Hazard Database (HADA) is based on a GIS helping to organize and manage volcanic information efficiently. HADA includes the following groups of information: (1) 1:25.000 scale geologic maps, (2) 1:25.000 topographic maps, (3) geochronologic data, (4) geochemical data, (5) structural information, (6) climatic data. Data must pass a quality control before they are included in the database. New data are easily integrated in the database. With the HADA database the IGME has started a systematic organization of the existing data. In the near future, the IGME will generate new information to be included in HADA, such as volcanological maps of the islands, structural information, geochronological data and other information to assess long term volcanic hazard analysis. HADA will permit

HJ (Iran) and HT (Cameroon) - Reflections on a new test for sexuality-based asylum claims in Britain

NARCIS (Netherlands)

Wessels, J.M.

2012-01-01

The case HJ (Iran) and HT (Cameroon) v Secretary of State for the Home Department [2010] UKSC 31 was celebrated as a 'fundamental shift in asylum law'. In this decision, the UK Supreme Court rejects the 'reasonably tolerable test' that had been applied in the case of the gay men HJ, a 40-year-old

Properties of volcanic soils in cold climate conditions

Science.gov (United States)

Kuznetsova, Elena

2017-04-01

Layers of volcanic ash and the Andosol soils derived from them may play an important role in preserving snow and ice as well as developing permafrost conditions in the immediate vicinity of volcanoes of high elevation or those situated at high latitudes, and land areas, often distant from volcanic activity that are either prone to permafrost or covered by snow and ice, but are affected by the deposition of subaerial ash. The special properties of volcanic ash that are responsible are critically reviewed particularly in relation to recent research in Kamchatka in the Far East of Russia. Of particular importance are the thermal properties and the unfrozen water contents of ash layers and the rate at which the weathering of volcanic glass takes place. Volcanic glass is the most easily weathered component of volcanic ejecta (Shoji et al., 1993; Kimble et al., 2000). There are many specific environmental conditions, including paleoclimate and present-day climate, the composition of volcanic tephra and glaciation history, which cause the differences in weathering and development of volcanic ash soils (Zehetner et al., 2003). The preservation of in situ, unweathered, and unaltered surficial ash-fall deposits in the cold regions has important implications for paleoclimate and glacial history. Ash-fall deposits, which trap and preserve the soils, sediments, and landforms on which they fall, can be used to resolve local climate conditions (temperature and moisture) at the ash site during ash-fall deposition. The preservation of detailed sedimentary features (e.g. bedding in the ash, sharpness of stratigraphic contacts) can tell us about their post-depositional history, whether they have been redeposited by wind or water, or overridden by glaciers (Marchant et al., 1996). Weathering of volcanic glass results in the development of amorphous clay minerals (e.g. allophane, opal, palagonite) but this takes place much slower in cold than under warmer climate conditions. Only few

The onset of the volcanism in the Ciomadul Volcanic Dome Complex (Eastern Carpathians): Eruption chronology and magma type variation

Science.gov (United States)

Molnár, Kata; Harangi, Szabolcs; Lukács, Réka; Dunkl, István; Schmitt, Axel K.; Kiss, Balázs; Garamhegyi, Tamás; Seghedi, Ioan

2018-04-01

Combined zircon U-Th-Pb and (U-Th)/He dating was applied to refine the eruption chronology of the last 2 Myr for the andesitic and dacitic Pilişca volcano and Ciomadul Volcanic Dome Complex (CVDC), the youngest volcanic area of the Carpathian-Pannonian region, located in the southernmost Harghita, eastern-central Europe. The proposed eruption ages, which are supported also by the youngest zircon crystallization ages, are much younger than the previously determined K/Ar ages. By dating every known eruption center in the CVDC, repose times between eruptive events were also accurately determined. Eruption of the andesite at Murgul Mare (1865 ± 87 ka) and dacite of the Pilişca volcanic complex (1640 ± 37 ka) terminated an earlier pulse of volcanic activity within the southernmost Harghita region, west of the Olt valley. This was followed by the onset of the volcanism in the CVDC, which occurred after several 100s kyr of eruptive quiescence. At ca. 1 Ma a significant change in the composition of erupted magma occurred from medium-K calc-alkaline compositions to high-K dacitic (Baba-Laposa dome at 942 ± 65 ka) and shoshonitic magmas (Malnaş and Bixad domes; 964 ± 46 ka and 907 ± 66 ka, respectively). Noteworthy, eruptions of magmas with distinct chemical compositions occurred within a restricted area, a few km from one another. These oldest lava domes of the CVDC form a NNE-SSW striking tectonic lineament along the Olt valley. Following a brief (ca. 100 kyr) hiatus, extrusion of high-K andesitic magma continued at Dealul Mare (842 ± 53 ka). After another ca. 200 kyr period of quiescence two high-K dacitic lava domes extruded (Puturosul: 642 ± 44 ka and Balvanyos: 583 ± 30 ka). The Turnul Apor lava extrusion occurred after a ca. 200 kyr repose time (at 344 ± 33 ka), whereas formation of the Haramul Mic lava dome (154 ± 16 ka) represents the onset of the development of the prominent Ciomadul volcano. The accurate determination of eruption dates shows that the

Developing International Guidelines on Volcanic Hazard Assessments for Nuclear Facilities

Science.gov (United States)

Connor, Charles

2014-05-01

Worldwide, tremendous progress has been made in recent decades in forecasting volcanic events, such as episodes of volcanic unrest, eruptions, and the potential impacts of eruptions. Generally these forecasts are divided into two categories. Short-term forecasts are prepared in response to unrest at volcanoes, rely on geophysical monitoring and related observations, and have the goal of forecasting events on timescales of hours to weeks to provide time for evacuation of people, shutdown of facilities, and implementation of related safety measures. Long-term forecasts are prepared to better understand the potential impacts of volcanism in the future and to plan for potential volcanic activity. Long-term forecasts are particularly useful to better understand and communicate the potential consequences of volcanic events for populated areas around volcanoes and for siting critical infrastructure, such as nuclear facilities. Recent work by an international team, through the auspices of the International Atomic Energy Agency, has focused on developing guidelines for long-term volcanic hazard assessments. These guidelines have now been implemented for hazard assessment for nuclear facilities in nations including Indonesia, the Philippines, Armenia, Chile, and the United States. One any time scale, all volcanic hazard assessments rely on a geologically reasonable conceptual model of volcanism. Such conceptual models are usually built upon years or decades of geological studies of specific volcanic systems, analogous systems, and development of a process-level understanding of volcanic activity. Conceptual models are used to bound potential rates of volcanic activity, potential magnitudes of eruptions, and to understand temporal and spatial trends in volcanic activity. It is these conceptual models that provide essential justification for assumptions made in statistical model development and the application of numerical models to generate quantitative forecasts. It is a

Multiple insecticide resistance mechanisms in Anopheles gambiae s.l. populations from Cameroon, Central Africa.

Science.gov (United States)

Nwane, Philippe; Etang, Josiane; Chouaїbou, Mouhamadou; Toto, Jean Claude; Koffi, Alphonsine; Mimpfoundi, Rémy; Simard, Frédéric

2013-02-22

Increasing incidence of DDT and pyrethroid resistance in Anopheles mosquitoes is seen as a limiting factor for malaria vector control. The current study aimed at an in-depth characterization of An. gambiae s.l. resistance to insecticides in Cameroon, in order to guide malaria vector control interventions. Anopheles gambiae s.l. mosquitoes were collected as larvae and pupae from six localities spread throughout the four main biogeographical domains of Cameroon and reared to adults in insectaries. Standard WHO insecticide susceptibility tests were carried out with 4% DDT, 0.75% permethrin and 0.05% deltamethrin. Mortality rates and knockdown times (kdt50 and kdt95) were determined and the effect of pre-exposure to the synergists DEF, DEM and PBO was assessed. Tested mosquitoes were identified to species and molecular forms (M or S) using PCR-RFLP. The hot ligation method was used to depict kdr mutations and biochemical assays were conducted to assess detoxifying enzyme activities. The An. arabiensis population from Pitoa was fully susceptible to DDT and permethrin (mortality rates>98%) and showed reduced susceptibility to deltamethrin. Resistance to DDT was widespread in An. gambiae s.s. populations and heterogeneous levels of susceptibility to permethrin and deltamethrin were observed. In many cases, prior exposure to synergists partially restored insecticide knockdown effect and increased mortality rates, suggesting a role of detoxifying enzymes in increasing mosquito survival upon challenge by pyrethroids and, to a lower extent DDT. The distribution of kdr alleles suggested a major role of kdr-based resistance in the S form of An. gambiae. In biochemical tests, all but one mosquito population overexpressed P450 activity, whereas baseline GST activity was low and similar in all field mosquito populations and in the control. In Cameroon, multiple resistance mechanisms segregate in the S form of An. gambiae resulting in heterogeneous resistance profiles, whereas in

Basaltic volcanic episodes of the Yucca Mountain region

International Nuclear Information System (INIS)

Crowe, B.M.

1990-01-01

The purpose of this paper is to summarize briefly the distribution and geologic characteristics of basaltic volcanism in the Yucca Mountain region during the last 10--12 Ma. This interval largely postdates the major period of silicic volcanism and coincides with and postdates the timing of major extensional faulting in the region. Field and geochronologic data for the basaltic rocks define two distinct episodes. The patterns in the volume and spatial distribution of these basaltic volcanic episodes in the central and southern part of the SNVF are used as a basis for forecasting potential future volcanic activity in vicinity of Yucca Mountain. 33 refs., 2 figs

Monogenetic volcanism: personal views and discussion

Science.gov (United States)

Németh, K.; Kereszturi, G.

2015-11-01

Monogenetic volcanism produces small-volume volcanoes with a wide range of eruptive styles, lithological features and geomorphic architectures. They are classified as spatter cones, scoria (or cinder) cones, tuff rings, maars (maar-diatremes) and tuff cones based on the magma/water ratio, dominant eruption styles and their typical surface morphotypes. The common interplay between internal, such as the physical-chemical characteristics of magma, and external parameters, such as groundwater flow, substrate characteristics or topography, plays an important role in creating small-volume volcanoes with diverse architectures, which can give the impression of complexity and of similarities to large-volume polygenetic volcanoes. In spite of this volcanic facies complexity, we defend the term "monogenetic volcano" and highlight the term's value, especially to express volcano morphotypes. This study defines a monogenetic volcano, a volcanic edifice with a small cumulative volume (typically ≤1 km3) that has been built up by one continuous, or many discontinuous, small eruptions fed from one or multiple magma batches. This definition provides a reasonable explanation of the recently recognized chemical diversities of this type of volcanism.

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.

Principal geological characteristics of the volcanic-type uranium deposits in China

International Nuclear Information System (INIS)

Fang Xiheng

2009-01-01

The volcanic-type uranium deposits in China distribute in two gigantic active belts, that is, circum-Pacific belt and latitudinal structure belt crossing Europe-Asia. The volcanic-type uranium deposits occur in continental volcanics,which are mainly composed of acid or alkali volcanics. Based on the study of 87 Sr/ 86 Sr initial ratio, REE distribution pattern and melt inclusion thermometry of volcanics, it is found that volcanic magma originated mainly from high-temperature melt of sialsphere and they were propably contaiminated partially by mantle materials. The volcanic eruption was controlled by regional fault and formed eruption belt, the beld can be divided into several sub-belt which was comprised by a serial eruption centres. The volcanic-type uranium deposits occur by the side of down-faulted red basin or associated with basic swarm. This means that the uranium mineralization is related to deep tectonics-magmatism. The paper proposes that the moderate erosion of volcanic belt is an important precondition to find uranium deposits. (authors)

Eocene volcanism and the origin of horizon A

Science.gov (United States)

Gibson, T.G.; Towe, K.M.

1971-01-01

A series of closely time-equivalent deposits that correlate with seismic reflector horizon A exists along the coast of eastern North America. These sediments of Late-Early to Early-Middle Eocene age contain an authigenic mineral suite indicative of the alteration of volcanic glass. A volcanic origin for these siliceous deposits onshore is consistent with a volcanic origin for the cherts of horizon A offshore.

Not Seeing the Cattle for the Elephants: The Implications of Discursive Linkages between Boko Haram and Wildlife Poaching in Waza National Park, Cameroon

Directory of Open Access Journals (Sweden)

Alice Kelly Pennaz

2018-01-01

Full Text Available The decline of wildlife in Central and West African border parks has been directly linked to Islamic terrorism in the region in media and government discourse. Using Waza National Park in the Far North Region of Cameroon as a case study, we show that wildlife declines in the park long preceded the appearance of Boko Haram, the extremist group best known for kidnapping over 200 girls in northern Nigeria. We also show that there is no evidence that Boko Haram are using wildlife products from the park to sustain their operations. Instead, the “poacher-as-terrorist” narrative obscures complex, historically embedded reasons for insecurity in northern Cameroon as well as massive losses of biodiversity in this region. The media and governments' focus on the “poacher-as-terrorist” narrative has important implications for the victims of Boko Haram, including mobile pastoralists. It is their cattle that are most likely a major source of sustenance and funding for the operations of Boko Haram. However, because these mobile pastoralist groups are “invisible” in the bush, their struggles remain ignored. We argue that the continued espousal of the “poacher-as-terrorist” narrative allows Boko Haram violence against mobile pastoralists to continue, and makes way for further environmental degradation in Cameroon's protected areas.

Use of a tool-set by Pan troglodytes troglodytes to obtain termites (Macrotermes) in the periphery of the Dja Biosphere Reserve, southeast Cameroon.

Science.gov (United States)

Deblauwe, Isra; Guislain, Patrick; Dupain, Jef; Van Elsacker, Linda

2006-12-01

At the northern periphery of the Dja Biosphere Reserve (southeastern Cameroon) we recorded a new use of a tool-set by Pan troglodytes troglodytes to prey on Macrotermes muelleri, M. renouxi, M. lilljeborgi, and M. nobilis. We recovered 79 puncturing sticks and 47 fishing probes at 17 termite nests between 2002 and 2005. The mean length of the puncturing sticks (n = 77) and fishing probes (n = 45) was 52 cm and 56 cm, respectively, and the mean diameter was 9 mm and 4.5 mm, respectively. Sixty-eight percent of 138 chimpanzee fecal samples contained major soldiers of four Macrotermes species. The chimpanzees in southeastern Cameroon appeared to be selective in their choice of plant material to make their tools. The tools found at our study site resemble those from other sites in this region. However, in southeastern Cameroon only one tool-set type was found, whereas two tool-set types have been reported in Congo. Our study suggests that, along with the different vegetation types and the availability of plant material around termite nests, the nest and gallery structure and foraging behavior of the different Macrotermes spp. at all Central African sites must be investigated before we can attribute differences in tool-use behavior to culture. (c) 2006 Wiley-Liss, Inc.

Local and remote infrasound from explosive volcanism

Science.gov (United States)

Matoza, R. S.; Fee, D.; LE Pichon, A.

2014-12-01

Explosive volcanic eruptions can inject large volumes of ash into heavily travelled air corridors and thus pose a significant societal and economic hazard. In remote volcanic regions, satellite data are sometimes the only technology available to observe volcanic eruptions and constrain ash-release parameters for aviation safety. Infrasound (acoustic waves ~0.01-20 Hz) data fill this critical observational gap, providing ground-based data for remote volcanic eruptions. Explosive volcanic eruptions are among the most powerful sources of infrasound observed on earth, with recordings routinely made at ranges of hundreds to thousands of kilometers. Advances in infrasound technology and the efficient propagation of infrasound in the atmosphere therefore greatly enhance our ability to monitor volcanoes in remote regions such as the North Pacific Ocean. Infrasound data can be exploited to detect, locate, and provide detailed chronologies of the timing of explosive volcanic eruptions for use in ash transport and dispersal models. We highlight results from case studies of multiple eruptions recorded by the International Monitoring System and dedicated regional infrasound networks (2008 Kasatochi, Alaska, USA; 2008 Okmok, Alaska, USA; 2009 Sarychev Peak, Kuriles, Russian Federation; 2010 Eyjafjallajökull, Icleand) and show how infrasound is currently used in volcano monitoring. We also present progress towards characterizing and modeling the variability in source mechanisms of infrasound from explosive eruptions using dedicated local infrasound field deployments at volcanoes Karymsky, Russian Federation and Sakurajima, Japan.

Volcanism Studies: Final Report for the Yucca Mountain Project

Energy Technology Data Exchange (ETDEWEB)

Bruce M. Crowe; Frank V. Perry; Greg A. Valentine; Lynn M. Bowker

1998-12-01

This report synthesizes the results of volcanism studies conducted by scientists at the Los Alamos National Laboratory and collaborating institutions on behalf of the Department of Energy's Yucca Mountain Project. An assessment of the risk of future volcanic activity is one of many site characterization studies that must be completed to evaluate the Yucca Mountain site for potential long-term storage of high-level radioactive waste. The presence of several basaltic volcanic centers in the Yucca Mountain region of Pliocene and Quaternary age indicates that there is a finite risk of a future volcanic event occurring during the 10,000-year isolation period of a potential repository. Chapter 1 introduces the volcanism issue for the Yucca Mountain site and provides the reader with an overview of the organization, content, and significant conclusions of this report. The risk of future basaltic volcanism is the primary topic of concern including both events that intersect a potential repository and events that occur near or within the waste isolation system of a repository. Future volcanic events cannot be predicted with certainty but instead are estimated using formal methods of probabilistic volcanic hazard assessment (PVHA). Chapter 2 describes the volcanic history of the Yucca Mountain region (YMR) and emphasizes the Pliocene and Quaternary volcanic record, the interval of primary concern for volcanic risk assessment. The distribution, eruptive history, and geochronology of Plio-Quaternary basalt centers are described by individual center emphasizing the younger postcaldera basalt (<5 Ma). The Lathrop Wells volcanic center is described in detail because it is the youngest basalt center in the YMR. The age of the Lathrop Wells center is now confidently determined to be about 75 thousand years old. Chapter 3 describes the tectonic setting of the YMR and presents and assesses the significance of multiple alternative tectonic models. The Crater Flat volcanic zone is

The use of indigenous techniques of communication for language learning: The case of Cameroon

OpenAIRE

Ebong, Balbina

2004-01-01

This study aimed at determining whether the use of indigenous techniques of communication can have a positive impact on the motivation of the learner of English as a foreign language in Cameroon. By indigenous techniques of communication we mean techniques like role-play, songs, the telling of folktales, riddles and proverbs. This work is intended as a contribution to the search for improvement of student motivation and enthusiasm, whereby they can be more responsive as they participate spont...

Cenozoic volcanic rocks of Saudi Arabia

Science.gov (United States)

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

2016-01-01

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

Microphysical Properties of Alaskan Volcanic Ash

Science.gov (United States)

Puthukkudy, A.; Espinosa, R.; Rocha Lima, A.; Remer, L.; Colarco, P. R.; Whelley, P.; Krotkov, N. A.; Young, K.; Dubovik, O.; Wallace, K.; Martins, J. V.

2017-12-01

Volcanic ash has the potential to cause a variety of severe problems for human health and the environment. Therefore, effective monitoring of the dispersion and fallout from volcanic ash clouds and characterization of the aerosol particle properties are essential. One way to acquire information from volcanic clouds is through satellite remote sensing: such images have greater coverage than ground-based observations and can present a "big picture" perspective. A challenge of remote sensing is that assumptions of certain properties of the target are often a pre-requisite for making accurate and quantitative retrievals. For example, detailed information about size distribution, sphericity, and optical properties of the constituent matter is needed or must be assumed. The same kind of information is also needed for atmospheric transport models to properly simulate the dispersion and fallout of volcanic ash. Presented here is a laboratory method to determine the microphysical and optical properties of volcanic ash samples collected from two Alaskan volcanoes with markedly different compositions. Our method uses a Polarized Imaging Nephelometer (PI-Neph) and a system that re-suspends the particles in an air flow. The PI-Neph measures angular light scattering and polarization of the re-suspended particles from 3o to 175o in scattering angle, with an angular resolution of 1o . Primary measurements include phase function and polarized phase function at three wavelengths (445nm, 532nm, and 661nm). Size distribution, sphericity, and complex refractive index are retrieved indirectly from the PI-Neph measurements using the GRASP (Generalized Retrieval of Aerosol and Surface Properties) inversion algorithm. We report the results of this method applied to samples from the Mt. Okmok (2008) and Mt. Katmai (1912) volcanic eruptions. To our knowledge, this is the first time direct measurements of phase matrix elements of ash from Mt. Okmok and Mt. Katmai have been reported. Retrieved

Volcanic hazard studies for the Yucca Mountain project

International Nuclear Information System (INIS)

Crowe, B.; Turrin, B.; Wells, S.; Perry, F.; McFadden, L.; Renault, C.E.; Champion, D.; Harrington, C.

1989-01-01

Volcanic hazard studies are ongoing to evaluate the risk of future volcanism with respect to siting of a repository for disposal of high-level radioactive waste at the Yucca Mountain site. Seven Quaternary basaltic volcanic centers are located a minimum distance of 12 km and a maximum distance of 47 km from the outer boundary of the exploration block. The conditional probability of disruption of a repository by future basaltic volcanism is bounded by the range of 10/sup /minus/8/ to 10/sup /minus/10/ yr/sup /minus/1/. These values are currently being reexamined based on new developments in the understanding of the evaluation of small volume, basaltic volcanic centers including: (1) Many, perhaps most, of the volcanic centers exhibit brief periods of eruptive activity separated by longer periods of inactivity. (2) The centers may be active for time spans exceeding 10 5 yrs, (3) There is a decline in the volume of eruptions of the centers through time, and (4) Small volume eruptions occurred at two of the Quaternary centers during latest Pleistocene or Holocene time. We classify the basalt centers as polycyclic, and distinguish them from polygenetic volcanoes. Polycyclic volcanism is characterized by small volume, episodic eruptions of magma of uniform composition over time spans of 10 3 to 10 5 yrs. Magma eruption rates are low and the time between eruptions exceeds the cooling time of the magma volumes. 25 refs., 2 figs

Volcanic eruption plumes on Io

International Nuclear Information System (INIS)

Strom, R.G.; Terrile, R.J.; Masursky, H.; Hansen, C.

1979-01-01

The detection of an umbrella-shaped plume extending about 280 km above the bright limb of Io was one of the most important discoveries made during the Voyager 1 encounter with the jovian system. This discovery proves that Io is volcanically active at present, and the number and magnitude of these eruptions indicate that Io is the most volcanically active body so far discovered in the Solar System. Preliminary analyses of these eruptive plumes are presented. (U.K.)

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.

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

The Lathrop Wells volcanic center

International Nuclear Information System (INIS)

Crowe, B.; Morley, R.

1992-01-01

The Lathrop Wells volcanic center is located 20 km south of the potential Yucca Mountain site, at the south end of the Yucca Mountain range. This paper discusses a detailed Study Plan which was prepared describing planned geochronology and field studies to assess the chronology of the Lathrop Wells volcanic center and other Quaternary volcanic centers in the region. A paper was published discussing the geomorphic and soil evidence for a late Pleistocene or Holoceno age for the main cone of the center. The purpose of this paper was to expose the ideas concerning the age of the Lathrop Wells center to scientific scrutiny. Additionally, field evidence was described suggesting the Lathrop Wells center may have formed from multiple eruptive events with significant intervals of no activity between events. This interpretation breaks with established convention in the volcanological literature that small volume basalt centers are monogenetic

Major-element geochemistry of the Silent Canyon--Black Mountain peralkaline volcanic centers, northwestern Nevada Test Site: applications to an assessment of renewed volcanism

International Nuclear Information System (INIS)

Crowe, B.M.; Sargent, K.A.

1979-01-01

The Silent Canyon and Black Mountain volcanic centers are located in the northern part of the Nevada Test Site. The Silent Canyon volcanic center is a buried cauldron complex of Miocene age (13 to 15 m.y.). Black Mountain volcanic center is an elliptical-shaped cauldron complex of late Miocene age. The lavas and tuffs of the two centers comprise a subalkaline-peralkaline association. Rock types range from quartz normative subalkaline trachyte and rhyolite to peralkaline commendite. The Gold Flat Member of the Thirsty Canyon Tuff (Black Mountain) is a pantellerite. The major-element geochemistry of the Black Mountain--Silent Canyon volcanic centers differ in the total range and distribution of SiO 2 , contents, the degree of peralkalinity (molecular Na 2 O + K 2 O > Al 2 O 3 ) and in the values of total iron and alumina through the range of rock types. These differences indicate that the suites were unrelated and evolved from differing magma bodies. The Black Mountain volcanic cycle represents a renewed phase of volcanism following cessation of the Timber Mountain--Silent Canyon volcanic cycles. Consequently, there is a small but numerically incalculable probability of recurrence of Black Mountain-type volcanism within the Nevada Test Site region. This represents a potential risk with respect to deep geologic storage of high-level radioactive waste at the Nevada Test Site

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.

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.

Ash production by attrition in volcanic conduits and plumes.

Science.gov (United States)

Jones, T J; Russell, J K

2017-07-17

Tephra deposits result from explosive volcanic eruption and serve as indirect probes into fragmentation processes operating in subsurface volcanic conduits. Primary magmatic fragmentation creates a population of pyroclasts through volatile-driven decompression during conduit ascent. In this study, we explore the role that secondary fragmentation, specifically attrition, has in transforming primary pyroclasts upon transport in volcanic conduits and plumes. We utilize total grain size distributions from a suite of natural and experimentally produced tephra to show that attrition is likely to occur in all explosive volcanic eruptions. Our experimental results indicate that fine ash production and surface area generation is fast (eruption column stability, tephra dispersal, aggregation, volcanic lightening generation, and has concomitant effects on aviation safety and Earth's climate.

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

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

Classifcation of volcanic structure in mesozoic era in the Fuzhou-Shaoxing area

International Nuclear Information System (INIS)

Zhang Fengqi.

1989-01-01

The volcanic structure in the Fuzhou-Shaoxing area can be classified into IV grades: the grade I be the zone of volcanic activity; the grade II be the second zone of volcanic activity; the grade III be the positive, negative volcanic structure; the grade IV be volcanic conduit, volcanic crater, concealed eruption breccia pipe. Based on the geological situation in this area, the different types of volcanic structure are also dealt with. In the mean time, both the embossed type in the depression area and the depressed type in the embossed area in the volcanic basin are pointed out. It is of great advantage to Uranium mineralization

Volcanic eruptions on Io

Science.gov (United States)

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

1981-01-01

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.

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.

Improving communication during volcanic crises on small, vulnerable islands

Science.gov (United States)

McGuire, W. J.; Solana, M. C.; Kilburn, C. R. J.; Sanderson, D.

2009-05-01

Increased exposure to volcanic hazard, particularly at vulnerable small islands, is driving an urgent and growing need for improved communication between monitoring scientists, emergency managers and the media, in advance of and during volcanic crises. Information gathering exercises undertaken on volcanic islands (Guadeloupe, St. Vincent and Montserrat) in the Lesser Antilles (eastern Caribbean), which have recently experienced - or are currently experiencing - volcanic action, have provided the basis for the compilation and publication of a handbook on Communication During Volcanic Emergencies, aimed at the principal stakeholder groups. The findings of the on-island surveys point up the critical importance of (1) bringing together monitoring scientists, emergency managers, and representatives of the media, well in advance of a volcanic crisis, and (2), ensuring that procedures and protocols are in place that will allow, as far as possible, effective and seamless cooperation and coordination when and if a crisis situation develops. Communication During Volcanic Emergencies is designed to promote and encourage both of these priorities through providing the first source-book addressing working relationships and inter-linkages between the stakeholder groups, and providing examples of good and bad practice. While targeting the volcanic islands of the eastern Caribbean, the source-book and its content are largely generic, and the advice and guidelines contained therein have equal validity in respect of improving communication before and during crises at any volcano, and have application to the communication issue in respect of a range of other geophysical hazards.

Self-potential anomalies in some Italian volcanic areas

Directory of Open Access Journals (Sweden)

C. Silenziario

1996-06-01

Full Text Available The study of Self-Potential (SP space and time variations in volcanic areas may provide useful information on both the geometrical structure of the volcanic apparatuses and the dynamical behaviour of the feeding and uprising systems. In this paper, the results obtained on the islands of Vulcano (Eolian arc and Ponza (Pontine archipelago and on the Mt. Somma-Vesuvius complex are shown. On the island of Vulcano and on the Mt. Somma-Vesuvius apparatus areal SP surveys were performed with the aim of evidencing anomalies closely associated to the zones of major volcanic activity. On the island of Vulcano a profile across the fumaroles along the crater rim of the Fossa Cone was also carried out in order to have a direct relationship between fumarolic fracture migration and flow rate and SP anomaly space and time variations. The areal survey on the island of Ponza, which is considered an inactive area, is assumed as a reference test with which to compare the amplitude and pattern of the anomalies in the active areas. A tentative interpretation of the SP anomalies in volcanic areas is suggested in terms of electrokinetic phenomena, related to the movement of fluids of both volcanic and non-volcanic origin.

Screening criteria of volcanic hazards aspect in the NPP site evaluation

International Nuclear Information System (INIS)

Nur Siwhan

2013-01-01

Studies have been conducted on the completeness of regulation in Indonesia particularly on volcanic hazards aspects in the evaluation of nuclear power plant site. Volcanic hazard aspect needed to identify potential external hazards that may endanger the safety of the operation of nuclear power plants. There are four stages for evaluating volcanic hazards, which are initial assessment, characterization sources of volcanic activity in the future, screening volcanic hazards and assessment of capable volcanic hazards. This paper discuss the third stage of the general evaluation which is the screening procedure of volcanic hazards. BAPETEN Chairman Regulation No. 2 Year of 2008 has only one screening criteria for missile volcanic phenomena, so it required screening criteria for other hazard phenomena that are pyroclastic flow density; lava flows; avalanche debris materials; lava; opening hole new eruptions, volcano missile; tsunamis; ground deformation; and hydrothermal system and ground water anomaly. (author)

Venus - Volcanic features in Atla Region

Science.gov (United States)

1991-01-01

This Magellan image from the Atla region of Venus shows several types of volcanic features and superimposed surface fractures. The area in the image is approximately 350 kilometers (217 miles) across, centered at 9 degrees south latitude, 199 degrees east longitude. Lava flows emanating from circular pits or linear fissures form flower-shaped patterns in several areas. A collapse depression approximately 20 kilometers by 10 kilometers (12 by 6 miles) near the center of the image is drained by a lava channel approximately 40 kilometers (25 miles) long. Numerous surface fractures and graben (linear valleys) criss-cross the volcanic deposits in north to northeast trends. The fractures are not buried by the lavas, indicating that the tectonic activity post-dates most of the volcanic activity.

Tropical Volcanic Soils From Flores Island, Indonesia

Directory of Open Access Journals (Sweden)

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

Mapping of schistosomiasis and soil-transmitted helminthiasis in the regions of centre, East and West Cameroon.

Directory of Open Access Journals (Sweden)

Louis-Albert Tchuem Tchuenté

Full Text Available BACKGROUND: Schistosomiasis and soil-transmitted helminthiasis (STH are widely distributed in Cameroon. Although mass drug administration (MDA of mebendazole is implemented nationwide, treatment with praziquantel was so far limited to the three northern regions and few health districts in the southern part of Cameroon, based on previous mapping conducted 25 years ago. To update the disease distribution map and determine where treatment with praziquantel should be extended, mapping surveys were conducted in three of the seven southern regions of Cameroon, i.e. Centre, East and West. METHODOLOGY: Parasitological surveys were conducted in April-May 2010 in selected schools in all 63 health districts of the three targeted regions, using appropriate research methodologies, i.e. Kato-Katz and urine filtration. PRINCIPAL FINDINGS: The results showed significant variation of schistosomiasis and STH prevalence between schools, villages, districts and regions. Schistosoma mansoni was the most prevalent schistosome species, with an overall prevalence of 5.53%, followed by S. haematobium (1.72% and S. guineensis (0.14%. The overall prevalence of schistosomiasis across the three regions was 7.31% (95% CI: 6.86-7.77%. The prevalence for Ascaris lumbricoides was 11.48 (95% CI: 10.93-12.04%, Trichuris trichiura 18.22% (95% CI: 17.56-18.90% and hookworms 1.55% (95% CI: 1.35-1.78%, with an overall STH prevalence of 24.10% (95% CI: 23.36-24.85% across the three regions. STH was more prevalent in the East region (46.57%; 95% CI: 44.41-48.75% in comparison to the Centre (25.12; 95% CI: 24.10-26.17% and West (10.49%; 95% CI: 9.57-11.51% regions. CONCLUSIONS/SIGNIFICANCE: In comparison to previous data, the results showed an increase of schistosomiasis transmission in several health districts, whereas there was a significant decline of STH infections. Based on the prevalence data, the continuation of annual or bi-annual MDA for STH is recommended, as well as an

Mapping of schistosomiasis and soil-transmitted helminthiasis in the regions of centre, East and West Cameroon.

Science.gov (United States)

Tchuem Tchuenté, Louis-Albert; Kamwa Ngassam, Romuald Isaka; Sumo, Laurentine; Ngassam, Pierre; Dongmo Noumedem, Calvine; Nzu, Deguy D'or Luogbou; Dankoni, Esther; Kenfack, Christian Mérimé; Gipwe, Nestor Feussom; Akame, Julie; Tarini, Ann; Zhang, Yaobi; Angwafo, Fru Fobuzski

2012-01-01

Schistosomiasis and soil-transmitted helminthiasis (STH) are widely distributed in Cameroon. Although mass drug administration (MDA) of mebendazole is implemented nationwide, treatment with praziquantel was so far limited to the three northern regions and few health districts in the southern part of Cameroon, based on previous mapping conducted 25 years ago. To update the disease distribution map and determine where treatment with praziquantel should be extended, mapping surveys were conducted in three of the seven southern regions of Cameroon, i.e. Centre, East and West. Parasitological surveys were conducted in April-May 2010 in selected schools in all 63 health districts of the three targeted regions, using appropriate research methodologies, i.e. Kato-Katz and urine filtration. The results showed significant variation of schistosomiasis and STH prevalence between schools, villages, districts and regions. Schistosoma mansoni was the most prevalent schistosome species, with an overall prevalence of 5.53%, followed by S. haematobium (1.72%) and S. guineensis (0.14%). The overall prevalence of schistosomiasis across the three regions was 7.31% (95% CI: 6.86-7.77%). The prevalence for Ascaris lumbricoides was 11.48 (95% CI: 10.93-12.04%), Trichuris trichiura 18.22% (95% CI: 17.56-18.90%) and hookworms 1.55% (95% CI: 1.35-1.78%), with an overall STH prevalence of 24.10% (95% CI: 23.36-24.85%) across the three regions. STH was more prevalent in the East region (46.57%; 95% CI: 44.41-48.75%) in comparison to the Centre (25.12; 95% CI: 24.10-26.17%) and West (10.49%; 95% CI: 9.57-11.51%) regions. In comparison to previous data, the results showed an increase of schistosomiasis transmission in several health districts, whereas there was a significant decline of STH infections. Based on the prevalence data, the continuation of annual or bi-annual MDA for STH is recommended, as well as an extension of praziquantel in identified moderate and high risk communities for

Variational data assimilation of satellite observations to estimate volcanic ash emissions

NARCIS (Netherlands)

Lu, S.

2017-01-01

Volcanic eruptions release a large amount of volcanic ash, which can pose hazard to human and animal health, land transportation, and aviation safety. Volcanic Ash Transport and Dispersion (VATD) models are critical tools to provide advisory information and timely volcanic ash forecasts. Due to the

Volcanic risk

International Nuclear Information System (INIS)

Rancon, J.P.; Baubron, J.C.

1995-01-01

This project follows the previous multi-disciplinary studies carried out by the French Bureau de Recherches Geologiques et Minieres (BRGM) on the two active volcanoes of the French lesser Antilles: Mt Pelee (Martinique) and Soufriere (Guadeloupe) for which geological maps and volcanic risk studies have been achieved. The research program comprises 5 parts: the study of pyroclastic deposits from recent eruptions of the two volcanoes for a better characterization of their eruptive phenomenology and a better definition of crisis scenarios; the study of deposits and structures of active volcanoes from Central America and the study of eruptive dynamics of andesite volcanoes for a transposition to Antilles' volcanoes; the starting of a methodological multi-disciplinary research (volcanology, geography, sociology...) on the volcanic risk analysis and on the management of a future crisis; and finally, the development of geochemical survey techniques (radon, CO 2 , H 2 O) on active volcanoes of Costa-Rica and Europe (Fournaise, Furnas, Etna) and their application to the Soufriere. (J.S.). 9 refs., 3 figs

Groundwater characteristics and problems in volcanic rock terrains

International Nuclear Information System (INIS)

Custodio, E.

1989-01-01

Volcanic rock formations, each with their own particular hydrogeological characteristics, occur in circumstances that cover a multiplicity of situations. These range from permeable porous rock formations to permeable fissured formations and include all types of intermediate situation between the two. The type of volcanism, distance from the source of emission, age, alteration processes and tectonics are all factors which determine their behaviour. Volcanic formations usually constitute a single aquifer system, even though this may be very heterogeneous and may locally be separated into clearly defined subunits. At times, formations may be hundreds of metres thick and are fairly permeable almost throughout. As a rule, volcanic material does not yield directly soluble salts to the water that flows through it. Mineralization of the water is due to the concentration of rainfall and the hydrolysis of silicates as a result of CO 2 being absorbed from the atmosphere and the ground, or as a result of volcanism itself. Cationic grouping is usually closely correlated to that of the rock formation in which the chemical composition is formed. Most environmental isotope and radioisotope techniques may be used, and at times are of unquestionable value. However, the existence of evaporation in the soil with possible isotopic fractionation, the effects of marked relief, the dilution of dissolved carbon by volcanic carbon and isotopic exchange brought about by volcanic carbon, etc., should be taken into account before valid conclusions are drawn. The paper uses examples taken from existing studies, mainly those being carried out in the Canary Islands (Spain). (author). 98 refs, 18 figs, 4 tabs

Status of volcanism studies for the Yucca Mountain Site Characterization Project

Energy Technology Data Exchange (ETDEWEB)

Crowe, B.; Perry, F.; Murrell, M.; Poths, J.; Valentine, G.A. [Los Alamos National Lab., NM (United States); Wells, S. [Univ. of California, Riverside, CA (United States); Bowker, L.; Finnegan, K. [Univ. of Nevada, Las Vegas, NV (United States); Geissman, J.; McFadden, L.

1995-02-01

Chapter 1 introduces the volcanism issue for the Yucca Mountain site and provides the reader with an overview of the organization, content, and significant conclusions of this report. The risk of future basaltic volcanism is the primary topic of concern including both events that intersect a potential repository and events that occur near or within the waste isolation system of a repository. Chapter 2 describes the volcanic history of the Yucca Mountain region (YMR) and emphasizes the Pliocene and Quaternary volcanic record, the interval of primary concern for volcanic risk assessment. The Lathrop Wells volcanic center is described in detail because it is the youngest basalt center in the YMR. Chapter 3 describes the tectonic setting of the YMR and presents and assesses the significance of multiple alternative tectonic models. Geophysical data are described for the YMR and are used as an aid to understand the distribution of basaltic volcanic centers. Chapter 4 discusses the petrologic and geochemical features of basaltic volcanism in the YMR, the southern Great Basin and the Basin and Range province. The long time of activity and characteristic small volume of the Postcaldera basalt of the YMR result in one of the lowest eruptive rates in a volcanic field in the southwest United States. Chapter 5 summarizes current concepts of the segregation, ascent, and eruption of basalt magma. Chapter 6 summarizes the history of volcanism studies (1979 through early 1994), including work for the Yucca Mountain Site Characterization Project and overview studies by the state of Nevada and the Nuclear Regulatory Commission. Chapter 7 summarizes probabilistic volcanic hazard assessment using a three-part conditional probability model. Chapter 8 describes remaining volcanism work judged to be needed to complete characterization studies for the YMR. Chapter 9 summarizes the conclusions of this volcanism status report.

Status of volcanism studies for the Yucca Mountain Site Characterization Project

International Nuclear Information System (INIS)

Crowe, B.; Perry, F.; Murrell, M.; Poths, J.; Valentine, G.A.; Wells, S.; Bowker, L.; Finnegan, K.; Geissman, J.; McFadden, L.

1995-02-01

Chapter 1 introduces the volcanism issue for the Yucca Mountain site and provides the reader with an overview of the organization, content, and significant conclusions of this report. The risk of future basaltic volcanism is the primary topic of concern including both events that intersect a potential repository and events that occur near or within the waste isolation system of a repository. Chapter 2 describes the volcanic history of the Yucca Mountain region (YMR) and emphasizes the Pliocene and Quaternary volcanic record, the interval of primary concern for volcanic risk assessment. The Lathrop Wells volcanic center is described in detail because it is the youngest basalt center in the YMR. Chapter 3 describes the tectonic setting of the YMR and presents and assesses the significance of multiple alternative tectonic models. Geophysical data are described for the YMR and are used as an aid to understand the distribution of basaltic volcanic centers. Chapter 4 discusses the petrologic and geochemical features of basaltic volcanism in the YMR, the southern Great Basin and the Basin and Range province. The long time of activity and characteristic small volume of the Postcaldera basalt of the YMR result in one of the lowest eruptive rates in a volcanic field in the southwest United States. Chapter 5 summarizes current concepts of the segregation, ascent, and eruption of basalt magma. Chapter 6 summarizes the history of volcanism studies (1979 through early 1994), including work for the Yucca Mountain Site Characterization Project and overview studies by the state of Nevada and the Nuclear Regulatory Commission. Chapter 7 summarizes probabilistic volcanic hazard assessment using a three-part conditional probability model. Chapter 8 describes remaining volcanism work judged to be needed to complete characterization studies for the YMR. Chapter 9 summarizes the conclusions of this volcanism status report

Yellow fever control in Cameroon: Where are we now and where are we going?

OpenAIRE

Wiysonge, Charles Shey; Nomo, Emmanuel; Mawo, Jeanne; Ofal, James; Mimbouga, Julienne; Ticha, Johnson; Ndumbe, Peter M

2008-01-01

Abstract Background Cameroon is one of 12 African countries that bear most of the global burden of yellow fever. In 2002 the country developed a five-year strategic plan for yellow fever control, which included strategies for prevention as well as rapid detection and response to outbreaks when they occur. We have used data collected by the national Expanded Programme on Immunisation to assess the progress made and challenges faced during the first four years of implementing the plan. Methods ...

X-ray microanalysis of volcanic ash

International Nuclear Information System (INIS)

Kearns, S L; Buse, B

2012-01-01

The 2010 eruption of Eyjafjallajökull volcano in Iceland demonstrated the disruptive nature of high-level volcanic ash emissions to the world's air traffic. The chemistry of volcanic material is complex and varied. Different eruptions yield both compositional and morphological variation. Equally a single eruption, such as that in Iceland will evolve over time and may potentially produce a range of volcanic products of varying composition and morphology. This variability offers the petrologist the opportunity to derive a tracer to the origins both spatially and temporally of a single particle by means of electron microbeam analysis. EPMA of volcanic ash is now an established technique for this type of analysis as used in tephrachronology. However, airborne paniculate material may, as in the case of Eyjafjallajökull, result in a particle size that is too small and too dispersed for preparation of standard EPMA mounts. Consequently SEM-EDS techniques are preferred for this type of quantitative analysis . Results of quantitative SEM-EDS analysis yield data with a larger precision error than EPMA yet sufficient to source the original eruption. Uncoated samples analyzed using variable pressure SEM yield slightly poorer results at modest pressures.

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

NARCIS (Netherlands)

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

2013-01-01

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

Formation and evolution of mesozoic volcanic basins in Gan-Hang tectonic belt

International Nuclear Information System (INIS)

Zhang Xingpu

1999-01-01

The author mainly discusses the principle model for the formation and the evolution of Mesozoic volcanic basins in the Gan-Hang Tectonic Belt, and describes the distinct evolution features between the internal and external sites of volcanic basins, the natural relation between the down-warped, down-faulted, collapse volcanic basins and volcanic domes, the relationship between the formation of inter layered fractured zones of the volcanic cover and the evolution of volcanic basins

Petrogeochemistry of Mesozoic basaltic volcanics in Daqingshan area

International Nuclear Information System (INIS)

Li Xiaoguang; Li Ziying; Wei Sanyuan; Qi Da'neng

2009-01-01

Through the discussion on petrogeochemistry of Later Mesozoic basaltic volcanics in Daqingshan Basin in Manzhouli area, combined with field observation and the predecessors' study, its magma evolution,genesis and diagenetic structural environment are discussed, and some suggestion are provided for the further work. Basaltic magma in this area is believed to be derived from mantle with incompatible elements which were later participated by some crustal materials. It is a partially melting product of mantle by early metasomatized fluid under lithosphere extension. Through petrogeochemical analysis of the volcanics and the contrast to the adjacent uranium-producing volcanics, it is concluded that this region has structural environment to form magma evolution series which are more favorable for volcanic hydrothermal-type uranium and polymetallic mineralization. (authors)

An ethical approach to socio-economic information sources in ongoing vulnerability and resilience studies: the Mount Cameroon case

Directory of Open Access Journals (Sweden)

Maria Ilaria Pannaccione Apa

2012-07-01

Full Text Available The study of the vulnerability of facing natural and man-made hazards, with the related resilient answers belong to the complex and articulate field of social sciences called ‘Disaster Anthropology’. Vulnerability is generally defined as a weak point in facing an aggressive event that is difficult to manage. Resilience is the subsequent capacity for self-repair after a sustained natural or anthropogenic stress. Consequently, the theoretical model of economic resilience is the ability to restore an economic background that can support the gradual recovery of social benefits following a disaster. Moreover, the presence in the territory of different systems of production (natural eco-systems and/or technical systems should allow multi-resilient communities. The mathematical structure of these economic theorems makes their practical application difficult inside an ethno-anthropological context, as it conflicts with cultural variables of the socio-structural fabric. An example can be given by some urban and rural family structures that are settled around the Mount Cameroon volcano (southwest Cameroon, in which the general psychological pressure increases because of both the constant exposure to natural hazards and the vulnerability arising from its social environment (e.g. castes, forced housing allocation, cultural estrangement to local chiefdom. Therefore, the rational heuristic model to be adopted in this social vulnerability study is performed by several combined analyses that have many interpretive obstacles. In 2009, within FP7-MIA-VITA, the first fieldwork mission for the study of socio-economic development of communities living around Mount Cameroon was launched. This completed 108 interviews across several social groups of different ethnicities and religions. The resulting information is being re-tested and verified from the second fieldwork mission in 2011, for completion of the study area.

Assessment of Aflatoxin Contamination of Maize, Peanut Meal and Poultry Feed Mixtures from Different Agroecological Zones in Cameroon

Directory of Open Access Journals (Sweden)

Jean Raphaël Kana

2013-04-01

Full Text Available Mycotoxins affect poultry production by being present in the feed and directly causing a negative impact on bird performance. Carry-over rates of mycotoxins in animal products are, in general, small (except for aflatoxins in milk and eggs therefore representing a small source of mycotoxins for humans. Mycotoxins present directly in human food represent a much higher risk. The contamination of poultry feed by aflatoxins was determined as a first assessment of this risk in Cameroon. A total of 201 samples of maize, peanut meal, broiler and layer feeds were collected directly at poultry farms, poultry production sites and poultry feed dealers in three agroecological zones (AEZs of Cameroon and analyzed for moisture content and aflatoxin levels. The results indicate that the mean of the moisture content of maize (14.1% was significantly (P < 0.05 higher than all other commodities (10.0%–12.7%. Approximately 9% of maize samples were positive for aflatoxin, with concentrations overall ranging from <2 to 42 µg/kg. Most of the samples of peanut meal (100%, broiler (93.3% and layer feeds (83.0% were positive with concentrations of positive samples ranging from 39 to 950 µg/kg for peanut meal, 2 to 52 µg/kg for broiler feed and 2 to 23 µg/kg for layer feed. The aflatoxin content of layer feed did not vary by AEZ, while the highest (16.8 µg/kg and the lowest (8.2 µg/kg aflatoxin content of broiler feed were respectively recorded in Western High Plateau and in Rainforest agroecological zones. These results suggest that peanut meal is likely to be a high risk feed, and further investigation is needed to guide promotion of safe feeds for poultry in Cameroon.

Cattle productivity on smallholder farms in the Western Highlands of Cameroon

International Nuclear Information System (INIS)

Njoya, A.; Mbanya, N.J.; Nguemdjom, A.; Kamga, P.; Ndi, C.; Kameni, A.; Nfi, N.A.

1999-01-01

A study of the traditional cattle production systems in the Western Highlands of Cameroon was carried out between August 1994 and September 1997. Fifty two cows selected from 14 farms in 4 locations were monitored monthly. Data were collected on calf and dam weight, dam's body condition, milk offtake and forage quality. Reproductive performance was monitored by measuring progesterone levels in milk sampled weekly. Crude protein content of grazed pastures rose from 12.5% in July to 14.5% in October and declined steadily to reach 4.5% in February. With such a decline in forage quality during the dry season, cows are unable to obtain their nutrient needs, thus productivity was low. Body condition score declined from medium (5.6) at calving to upper low (4.5) 4 months after the initiation of milk offtake. Body weight of cows decreased by nearly 14% during the same period. The interval between calving to first progesterone rise, calving to conception, and inter-calving intervals were 172 ± 116, 185 ± 106 and 448 ± 86 days, respectively. Milk offtake averaged 1.29 ± 0.44 kg/cow/day for a lactation length of 10.5 months. A significant effect of season was detected in milk offtake (P <0.001), body condition score (P <0.05), body weight of cows (P <0.05), intervals from calving to first progesterone rise (P <0.05), calving to conception (P <0.05) and inter-calving interval (P <0.01). Supplementary feeding during the dry season and early lactation to cover the nutrient requirements of the cows in the traditional production system of Western Highlands of Cameroon is recommended and forms the purpose of the second part of this study which is now underway. (author)

Nuclear medicine and the management of prostate cancer in Yaounde - Cameroon

International Nuclear Information System (INIS)

Dong a Zok, F.; Mbodj, M.; Assiga Ahanda, Y.M.; Angwafor, F.

2009-01-01

Prostate cancer is the most frequent neoplasm affecting males above 50 years old in developed countries. Previous studies carried out in Cameroon have shown that, this condition is not infrequent. Late diagnosis is equally common. The advent of nuclear medicine technology in the year 2000 has enabled the possibility of prostate specific antigen (P.S.A.) assay and imaging by bone scintigraphy. In this study, we aimed at assessing the contributions of P.S.A. assay and bone scintigraphy in the management of prostate cancer in Cameroon. Within a 5 years period (January 2003 - December 2007) 360 patients had biopsy proven (Gleason score) prostate adenocarcinoma. The age ranged from 50 to 85 years with a mean of 67 years. Those aged between 60 to 69 years were more affected. The patients were divided into 2 groups: a first one accruing of 250 patients with a previous bone scintigraphy carried out before treatment and a second group of patients who underwent a bone scintigraphy during treatment. Clinical features digital rectal examination, endorectal echography were noted. P.S.A. levels and bone scintigraphy results were also noted. Most of these patients (80.56%) presented with advanced lesions with metastases. Orchiectomy and hormonotherapy were the most used methods of treatment due to late diagnosis. Bone scintigraphy-evidenced lesions were mainly located (92.25%) at the dorso-lumbar region of the spine. There is a correlation between the following variables: clinical features, namely, digital rectal examinations, P.S.A. blood levels, ultrasound, histology and bone scintigraphy. Therefore, we can conclude that, P.S.A. is an important marker of prostate cancer. Its association with bone scintigraphy is appropriate for the detection of bone metastases. (authors)

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,…

From Chicken Breath to the Killer Lakes of Cameroon: Uniting Seven Interesting Phenomena with a Single Chemical Underpinning.

Science.gov (United States)

DeLorenzo, Ron

2001-01-01

Recommends integrating different applications to serve the need for students to know the relevancy of the course of their future. Uses different and unrelated phenomena to teach equilibria. Introduces six phenomena; (1) Killer Lakes of Cameroon, (2) Chicken Breath, (3) The Permian Ocean, (4) Snow Line, (5) Hard-Water Boiler Scale, and (6)…

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

Science.gov (United States)

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

2016-06-01

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

Fluids in volcanic and geothermal systems

Science.gov (United States)

Sigvaldason, Gudmundur E.

Mineral buffers control the composition of most volatile components of magmas and dissolved species in geothermal fluids. The only element which occurs in significant quantities in volcanic and geothermal fluids and is not controlled by mineral buffers is chlorine. It is argued that in absence of marine influence, geothermal fluids reflect the chlorine content of associated magmatic fluids. The chlorine content of oceanic volcanic rocks has a positive correlation with elements, which are believed to indicate a heterogenous source region. Since the source is generally believed to be the Earth's mantle, the implication is that the mantle is heterogenous with regard to chlorine and other volatiles. Such heterogeneities would have important consequences for genesis and distribution of ore. All major magma types of the oceanic environment occur in Iceland. Their spatial distribution is closely related to a volcanotectonic pattern, suggesting crustal control. A geophysical model of crustal accretion in a rift zone is used in conjunction with classical petrology to predict geochemical processes in a rift zone crust. The model has two kinematic parameters-drift rate and subsidence rate-which combined describe trajectories of mass particles deposited on the surface. When considering in conjunction with thermal gradients of the rift zone a series of metamorphic reactions and chemical fractionation processes are bound to occur, eventually resulting in a layering of the oceanic crust. The physical parameters result in a derived variable, rift zone residence time, which depends on the width of a rift zone. Long residence times in a wide rift zone lead to multistage recycling of material. Other properties of the model, based on geometric arrangement of productive fissure swarms within a rift zone, explain off-rift volcanism as directly related to rift zone processes, either as plate trapped magmatic domains or a transgressive thermal anomaly into an older crust. Off

[Health and drug consumption profile 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 consumer survey. Their socioeconomic profile of these consumers was much higher than that of the general population. This indicates that the poorest do not use health facilities or even self-medication. Within the population of healthcare consumers, women and children used private for-profit (60 %) and nonprofit (65 %) private health facilities most often, while men used mainly private pharmacies (60 %) and street drug (medication) sellers (62 %). In all, 85 % of the users of formal drug retailers had had a consultation with a healthcare provider. The average consultation cost was 1,440 CFA Francs, but the 7 % who paid the provider directly had an average cost of 1,794 CFA Francs. In all, 22 % did not pay at all, because of free consultations in some health facilities (40 %), personal relationships with prescribers, or other reasons. Hospitalization costs averaged 4,800 CFA Francs, and medical examinations 4,534 CFA Francs. These two categories had the highest percentage of insured patients (12 % and 5 %). Drug costs were 5,067 CFA Francs from pharmacies and 1,308 CFA Francs in the street. Total healthcare costs per person averaged 14,990 CFA Francs. Weighted, drugs accounted for the largest share, followed by hospitalisation, medical examinations, consultations, and transportation. In the formal sector, less than 10 % reported paying fees directly to the healthcare providers rather than to the HF cashier. Except for consultation in the public sector, paying providers was associated with a lower bill. However, 24 % purchased drugs from the healthcare workers, which indicates that drug sales are

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.

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

‘My "veil" does not go with my jeans’: veiling, fundamentalism, education and women’s agency in northern Cameroon

NARCIS (Netherlands)

van Santen, J.C.M.

2009-01-01

This article demonstrates that the struggle over the Muslim ‘veil’ in public schools, which is related to tensions between the norms of secular democracy and principles of religious tolerance, has also become a topic of debate in Cameroon. I take the life of a young woman, Maimouna, whose life I

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

Investigating the role of male advantage and female disadvantage in explaining the discrimination effect of the gender pay gap in the Cameroon labor market. Oaxaca-Ransom decomposition approach

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Dickson Thomas NDAMSA

2015-05-01

Full Text Available The paper assesses the sources of gender-based wage differentials and investigates the relative importance of the endowment effect, female disadvantage and male advantage in explaining gender-based wage differentials in the Cameroon labor market. Use is made of the Ordinary Least Square technique and the Oaxaca-Ransom decomposition. Oaxaca-Ransom decomposition results show that primary education, secondary education, tertiary education and professional training are sources of the gender pay gap. Our results also underline the importance of working experience, formal sector employment and urban residency in explaining wage differentials between male and female workers in the Cameroon labour market. Our findings reveal that education human capital explains a greater portion of the endowment effect and contributes little to the discrimination effect. Essentially, we observe that the discrimination effect has a worsening effect on the gender pay gap compared to the mitigating role of the endowment effect. Again, our results show that a greater part of the discrimination effect of the gender pay gap is attributed to female disadvantage in the Cameroon labor market.

Volcanic Eruptions and Climate: Outstanding Research Issues

Science.gov (United States)

Robock, Alan

2016-04-01

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

VOLCANIC TSUNAMI GENERATING SOURCE MECHANISMS IN THE EASTERN CARIBBEAN REGION

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George Pararas-Carayannis

2004-01-01

Full Text Available Earthquakes, volcanic eruptions, volcanic island flank failures and underwater slides have generated numerous destructive tsunamis in the Caribbean region. Convergent, compressional and collisional tectonic activity caused primarily from the eastward movement of the Caribbean Plate in relation to the North American, Atlantic and South American Plates, is responsible for zones of subduction in the region, the formation of island arcs and the evolution of particular volcanic centers on the overlying plate. The inter-plate tectonic interaction and deformation along these marginal boundaries result in moderate seismic and volcanic events that can generate tsunamis by a number of different mechanisms. The active geo-dynamic processes have created the Lesser Antilles, an arc of small islands with volcanoes characterized by both effusive and explosive activity. Eruption mechanisms of these Caribbean volcanoes are complex and often anomalous. Collapses of lava domes often precede major eruptions, which may vary in intensity from Strombolian to Plinian. Locally catastrophic, short-period tsunami-like waves can be generated directly by lateral, direct or channelized volcanic blast episodes, or in combination with collateral air pressure perturbations, nuéss ardentes, pyroclastic flows, lahars, or cascading debris avalanches. Submarine volcanic caldera collapses can also generate locally destructive tsunami waves. Volcanoes in the Eastern Caribbean Region have unstable flanks. Destructive local tsunamis may be generated from aerial and submarine volcanic edifice mass edifice flank failures, which may be triggered by volcanic episodes, lava dome collapses, or simply by gravitational instabilities. The present report evaluates volcanic mechanisms, resulting flank failure processes and their potential for tsunami generation. More specifically, the report evaluates recent volcanic eruption mechanisms of the Soufriere Hills volcano on Montserrat, of Mt. Pel

Volcanic systems of Iceland and their magma source

Science.gov (United States)

Sigmarsson, Olgeir

2017-04-01

Several active hot-spot volcanoes produce magma from mantle sources which composition varies on decadal time scale. This is probably best demonstrated by the recent work of Pietruszka and collaborators on Kilauea, Hawaii. In marked contrast, basalt lavas from volcanic system in Iceland located above the presumed centre of the Iceland mantle plume have uniform isotope composition over the last 10 thousand years. Volcanic systems are composed of a central volcano and a fissure swarm, or a combination of both and they represent a fundamental component of the neovolcanic zones in Iceland. Four such systems, those of Askja, Bárðarbunga, Kverkfjöll and Grímsvötn in central Iceland were chosen for investigation. The last three have central volcanoes covered by the Vatnajökull ice-sheet whereas part of their fissure swarms is ice-free. Tephra produced during subglacial eruptions together with lavas from the fissure swarms of Holocene age have been collected and analysed for Sr, Nd and Th isotope ratios. Those volcanic formations that can be univocally correlated to a given volcanic system display uniform isotope ratio but different from one volcanic system to another. An exception to this regularity is that Askja products have isotope ratios indistinguishable from those of Gímsvötn, but since these volcanic systems lies far apart their lava fields do not overlap. A practical aspect of these findings was demonstrated during the rifting event of Bárðarbunga and fissure eruption forming the Holuhraun lava field. Relatively low, O isotope ratios in these basalts and heterogeneous macrocrystal composition have been ascribed to important metabasaltic crustal contamination with or without crystal mush recycling. In that case a surprisingly efficient magma mixing and melt homogenization must have occurred in the past beneath the volcanic systems. One possibility is that during the rapid deglaciation much mantle melting occurred and melts accumulated at the mantle

Explosive Volcanic Activity at Extreme Depths: Evidence from the Charles Darwin Volcanic Field, Cape Verdes

Science.gov (United States)

Kwasnitschka, T.; Devey, C. W.; Hansteen, T. H.; Freundt, A.; Kutterolf, S.

2013-12-01

Volcanic eruptions on the deep sea floor have traditionally been assumed to be non-explosive as the high-pressure environment should greatly inhibit steam-driven explosions. Nevertheless, occasional evidence both from (generally slow-) spreading axes and intraplate seamounts has hinted at explosive activity at large water depths. Here we present evidence from a submarine field of volcanic cones and pit craters called Charles Darwin Volcanic Field located at about 3600 m depth on the lower southwestern slope of the Cape Verdean Island of Santo Antão. We examined two of these submarine volcanic edifices (Tambor and Kolá), each featuring a pit crater of 1 km diameter, using photogrammetric reconstructions derived from ROV-based imaging followed by 3D quantification using a novel remote sensing workflow, aided by sampling. The measured and calculated parameters of physical volcanology derived from the 3D model allow us, for the first time, to make quantitative statements about volcanic processes on the deep seafloor similar to those generated from land-based field observations. Tambor cone, which is 2500 m wide and 250 m high, consists of dense, probably monogenetic medium to coarse-grained volcaniclastic and pyroclastic rocks that are highly fragmented, probably as a result of thermal and viscous granulation upon contact with seawater during several consecutive cycles of activity. Tangential joints in the outcrops indicate subsidence of the crater floor after primary emplacement. Kolá crater, which is 1000 m wide and 160 m deep, appears to have been excavated in the surrounding seafloor and shows stepwise sagging features interpreted as ring fractures on the inner flanks. Lithologically, it is made up of a complicated succession of highly fragmented deposits, including spheroidal juvenile lapilli, likely formed by spray granulation. It resembles a maar-type deposit found on land. The eruption apparently entrained blocks of MORB-type gabbroic country rocks with

Supervolcanoes within an ancient volcanic province in Arabia Terra, Mars.

Science.gov (United States)

Michalski, Joseph R; Bleacher, Jacob E

2013-10-03

Several irregularly shaped craters located within Arabia Terra, Mars, represent a new type of highland volcanic construct and together constitute a previously unrecognized Martian igneous province. Similar to terrestrial supervolcanoes, these low-relief paterae possess a range of geomorphic features related to structural collapse, effusive volcanism and explosive eruptions. Extruded lavas contributed to the formation of enigmatic highland ridged plains in Arabia Terra. Outgassed sulphur and erupted fine-grained pyroclastics from these calderas probably fed the formation of altered, layered sedimentary rocks and fretted terrain found throughout the equatorial region. The discovery of a new type of volcanic construct in the Arabia volcanic province fundamentally changes the picture of ancient volcanism and climate evolution on Mars. Other eroded topographic basins in the ancient Martian highlands that have been dismissed as degraded impact craters should be reconsidered as possible volcanic constructs formed in an early phase of widespread, disseminated magmatism on Mars.

Miocene volcanism in the Oaş-Gutâi Volcanic Zone, Eastern Carpathians, Romania: Relationship to geodynamic processes in the Transcarpathian Basin

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Kovacs, Marinel; Seghedi, Ioan; Yamamoto, Masatsugu; Fülöp, Alexandrina; Pécskay, Zoltán; Jurje, Maria

2017-12-01

We present the first comprehensive study of Miocene volcanic rocks of the Oaş-Gutâi Volcanic Zone (OGVZ), Romania, which are exposed in the eastern Transcarpathian Basin (TB), within the Eastern Alpine-Western Carpathian-Northern Pannonian (ALCAPA) block. Collision between the ALCAPA block and Europe at 18-16 Ma produced the Carpathian fold-and-thrust belt. This was followed by clockwise rotation and an extensional regime forming core complexes of the separated TB fragment. Based on petrographic and geochemical data, including Srsbnd Nd isotopic compositions and Ksbnd Ar ages, we distinguish three types of volcanic activity in the OGVZ: (1) early Miocene felsic volcanism that produced caldera-related ignimbrites in the Gutâi Mountains (15.4-14.8 Ma); (2) widespread middle-late Miocene intermediate/andesitic volcanism (13.4-7.0 Ma); and (3) minor late Miocene andesitic/rhyolitic volcanism comprising the Oraşu Nou rhyolitic volcano and several andesitic-dacitic domes in the Oaş Mountains (11.3-9.5 Ma). We show that magma evolution in the OGVZ was controlled by assimilation-fractional crystallization and magma-mixing processes within an interconnected multi-level crustal magmatic reservoir. The evolution of volcanic activity within the OGVZ was controlled by the geodynamics of the Transcarpathian Basin. The early felsic and late intermediate Miocene magmas were emplaced in a post-collisional setting and were derived from a mantle source region that was modified by subduction components (dominantly sediment melts) and lower crust. The style of volcanism within the eastern TB system exhibits spatial variations, with andesitic composite volcanoes (Gutâi Mountains) observed at the margins, and isolated andesitic-rhyolitic monogenetic volcanoes (Oaş Mountains) in the center of the basin.

Do Students Eventually Get to Publish their Research Findings? The Case of Human Immunodeficiency Virus/Acquired Immunodeficiency Syndrome Research in Cameroon.

Science.gov (United States)

Munung, Ns; Vidal, L; Ouwe-Missi-Oukem-Boyer, O

2014-05-01

Scientific publication is commonly used to communicate research findings and in most academic/research settings, to evaluate the potential of a researcher and for recruitment and promotion. It has also been said that researchers have the duty to make public, the findings of their research. As a result, researchers are encouraged to share their research findings with the scientific world through peer review publications. In this study, we looked at the characteristics and publication rate of theses that documented studies on human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome in Cameroon. TO CHECK IF A THESIS RESULTED IN A PUBLICATION, WE SEARCHED: A database of publications on HIV in Cameroon, African Journals Online, PubMed and Google scholar. For each publication we recorded if the student was an author, the position of the student in the author listing, the journal and where the journal was indexed. We also looked at the impact factor of the journals. One hundred and thirty theses/dissertations were included in the study, 74.6% (97/130) were written as part of a medical degree (MD), 23.8% (31/130) a postgraduate (PG) degree and 1.5% (2/130) for a Doctorate/PhD. On a whole, 13.9% (18/130) of the theses resulted in at least one publication in a scientific journal with a total of 22 journal articles, giving a mean publication rate of 0.17 article/thesis, 86.4% (11/22) were indexed on PubMed, 9.1% (2/22) on African Journals Online and 4.6% (1/22) on Google scholar. One PG thesis led to two book chapters. The student was the first author in 22.7% (5/22) of the articles and not an author in 9.1% (2/22) of the articles. Student supervisor was an author in all the articles. This study reveals that most students in Cameroon failed to transform their theses/dissertations to scientific publications. This indicates an urgent need to sensitize students on the importance of presenting their research findings in scientific meetings and peer reviewed journals

Explosive volcanism, shock metamorphism and the K-T boundary

International Nuclear Information System (INIS)

Desilva, S.L.; Sharpton, V.L.

1988-01-01

The issue of whether shocked quartz can be produced by explosive volcanic events is important in understanding the origin of the K-T boundary constituents. Proponents of a volcanic origin for the shocked quartz at the K-T boundary cite the suggestion of Rice, that peak overpressures of 1000 kbars can be generated during explosive volcanic eruptions, and may have occurred during the May, 1980 eruption of Mt. St. Helens. Attention was previously drawn to the fact that peak overpressures during explosive eruptions are limited by the strength of the rock confining the magma chamber to less than 8 kbars even under ideal conditions. The proposed volcanic mechanisms for generating pressures sufficient to shock quartz are further examined. Theoretical arguments, field evidence and petrographic data are presented showing that explosive volcanic eruptions cannot generate shock metamorphic features of the kind seen in minerals at the K-T boundary

Global time-size distribution of volcanic eruptions on Earth.

Science.gov (United States)

Papale, Paolo

2018-05-01

Volcanic eruptions differ enormously in their size and impacts, ranging from quiet lava flow effusions along the volcano flanks to colossal events with the potential to affect our entire civilization. Knowledge of the time and size distribution of volcanic eruptions is of obvious relevance for understanding the dynamics and behavior of the Earth system, as well as for defining global volcanic risk. From the analysis of recent global databases of volcanic eruptions extending back to more than 2 million years, I show here that the return times of eruptions with similar magnitude follow an exponential distribution. The associated relative frequency of eruptions with different magnitude displays a power law, scale-invariant distribution over at least six orders of magnitude. These results suggest that similar mechanisms subtend to explosive eruptions from small to colossal, raising concerns on the theoretical possibility to predict the magnitude and impact of impending volcanic eruptions.

SYSTHESIS OF VOLCANISM STUDIES FOR THE YUCCA MOUNTAIN SITE CHARACTERIZATION PROJECT

International Nuclear Information System (INIS)

FV PERRY; GA CROWE; GA VALENTINE; LM BOWKER

1997-01-01

This report synthesizes the results of volcanism studies conducted by scientists at the Los Alamos National Laboratory and collaborating institutions on behalf of the Department of Energy's Yucca Mountain Project. Chapter 1 introduces the volcanism issue for the Yucca Mountain site and provides the reader with an overview of the organization, content, and significant conclusions of this report. The hazard of future basaltic volcanism is the primary topic of concern including both events that intersect a potential repository and events that occur near or within the waste isolation system of a repository. Future volcanic events cannot be predicted with certainty but instead are estimated using formal methods of probabilistic volcanic hazard assessment (PVHA). Chapter 2 describes the volcanic history of the Yucca Mountain region (YMR) and emphasizes the Pliocene and Quaternary volcanic record, the interval of primary concern for volcanic risk assessment. The distribution, eruptive history, and geochronology of Plio-Quaternary basalt centers are described by individual center emphasizing the younger postcaldera basalt ( -7 events per year. Bounding probability estimates are used to assess possible implications of not drilling aeromagnetic anomalies in the Arnargosa Valley and Crater Flat. The results of simulation modeling are used to assess the sensitivity of the disruption probability for the location of northeast boundaries of volcanic zones near the Yucca Mountain site. A new section on modeling of radiological releases associated with surface and subsurface magmatic activity has been added to chapter 6. The modeling results are consistent with past total system performance assessments that show future volcanic and magmatic events are not significant components of repository performance and volcanism is not a priority issue for performance assessment studies

Monitoring and forecasting Etna volcanic plumes

Directory of Open Access Journals (Sweden)

S. Scollo

2009-09-01

Full Text Available In this paper we describe the results of a project ongoing at the Istituto Nazionale di Geofisica e Vulcanologia (INGV. The objective is to develop and implement a system for monitoring and forecasting volcanic plumes of Etna. Monitoring is based at present by multispectral infrared measurements from the Spin Enhanced Visible and Infrared Imager on board the Meteosat Second Generation geosynchronous satellite, visual and thermal cameras, and three radar disdrometers able to detect ash dispersal and fallout. Forecasting is performed by using automatic procedures for: i downloading weather forecast data from meteorological mesoscale models; ii running models of tephra dispersal, iii plotting hazard maps of volcanic ash dispersal and deposition for certain scenarios and, iv publishing the results on a web-site dedicated to the Italian Civil Protection. Simulations are based on eruptive scenarios obtained by analysing field data collected after the end of recent Etna eruptions. Forecasting is, hence, supported by plume observations carried out by the monitoring system. The system was tested on some explosive events occurred during 2006 and 2007 successfully. The potentiality use of monitoring and forecasting Etna volcanic plumes, in a way to prevent threats to aviation from volcanic ash, is finally discussed.

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

Global volcanic earthquake swarm database and preliminary analysis of volcanic earthquake swarm duration

Directory of Open Access Journals (Sweden)

S. R. McNutt

1996-06-01

Full Text Available Global data from 1979 to 1989 pertaining to volcanic earthquake swarms have been compiled into a custom-designed relational database. The database is composed of three sections: 1 a section containing general information on volcanoes, 2 a section containing earthquake swarm data (such as dates of swarm occurrence and durations, and 3 a section containing eruption information. The most abundant and reliable parameter, duration of volcanic earthquake swarms, was chosen for preliminary analysis. The distribution of all swarm durations was found to have a geometric mean of 5.5 days. Precursory swarms were then separated from those not associated with eruptions. The geometric mean precursory swarm duration was 8 days whereas the geometric mean duration of swarms not associated with eruptive activity was 3.5 days. Two groups of precursory swarms are apparent when duration is compared with the eruption repose time. Swarms with durations shorter than 4 months showed no clear relationship with the eruption repose time. However, the second group, lasting longer than 4 months, showed a significant positive correlation with the log10 of the eruption repose period. The two groups suggest that different suites of physical processes are involved in the generation of volcanic earthquake swarms.

Volcanic deformation in the Andes

Science.gov (United States)

Riddick, S.; Fournier, T.; Pritchard, M.

2009-05-01

We present the results from an InSAR survey of volcanic activity in South America. We use data from the Japanese Space Agency's ALOS L-band radar satellite from 2006-2009. The L-band instrument provides better coherence in densely vegetated regions, compared to the shorter wave length C-band data. The survey reveals volcano related deformation in regions, north, central and southern, of the Andes volcanic arc. Since observations are limited to the austral summer, comprehensive coverage of all volcanoes is not possible. Yet, our combined observations reveal volcanic/hydrothermal deformation at Lonquimay, Llaima, Laguna del Maule, and Chaitén volcanoes, extend deformation measurements at Copahue, and illustrate temporal complexity to the previously described deformation at Cerro Hudson and Cordón Caulle. No precursory deformation is apparent before the large Chaitén eruption (VEI_5) of 2 May 2008, (at least before 16 April) suggesting rapid magma movement from depth at this long dormant volcano. Subsidence at Ticsani Volcano occurred coincident with an earthquake swarm in the same region.

Monitoring the Sumatra volcanic arc with InSAR

Science.gov (United States)

Chaussard, E.; Hong, S.; Amelung, F.

2009-12-01

The Sumatra volcanic arc is the result of the subduction of the Indo-Australian plate under the Sunda plate. The arc consists of 35 known volcanic centers, subaerials on the west coast of the Sumatra and Andaman Islands and submarines between these islands. Six active centers are known in the Sumatra volcanic arc. Surface deformation in volcanic areas usually indicates movement of magma or hydrothermal fluids at depth. Here we present a satellite-based Interferometric synthetic aperture radar (InSAR) survey of the Sumatra volcanic arc using ALOS data. Spanning the years 2007 to beginning of 2009, our survey reveals the background level of activity of the 35 volcanoes. We processed data from 40 tracks (24 in descending orbit and 16 in ascending orbit) to cover the whole Sumatra arc. In the first results five of these six known active centers show no sign of activity: Dempo, Kaba, Marapi, Talang and Peuet. The remaining active volcano, Mount Kerinci, has an ambiguous signal. We used pair-wise logic and InSAR time series of the available ALOS data to determine if the observed InSAR signal is caused by ground deformation or by atmospheric delays.

Global monsoon precipitation responses to large volcanic eruptions.

Science.gov (United States)

Liu, Fei; Chai, Jing; Wang, Bin; Liu, Jian; Zhang, Xiao; Wang, Zhiyuan

2016-04-11

Climate variation of global monsoon (GM) precipitation involves both internal feedback and external forcing. Here, we focus on strong volcanic forcing since large eruptions are known to be a dominant mechanism in natural climate change. It is not known whether large volcanoes erupted at different latitudes have distinctive effects on the monsoon in the Northern Hemisphere (NH) and the Southern Hemisphere (SH). We address this issue using a 1500-year volcanic sensitivity simulation by the Community Earth System Model version 1.0 (CESM1). Volcanoes are classified into three types based on their meridional aerosol distributions: NH volcanoes, SH volcanoes and equatorial volcanoes. Using the model simulation, we discover that the GM precipitation in one hemisphere is enhanced significantly by the remote volcanic forcing occurring in the other hemisphere. This remote volcanic forcing-induced intensification is mainly through circulation change rather than moisture content change. In addition, the NH volcanic eruptions are more efficient in reducing the NH monsoon precipitation than the equatorial ones, and so do the SH eruptions in weakening the SH monsoon, because the equatorial eruptions, despite reducing moisture content, have weaker effects in weakening the off-equatorial monsoon circulation than the subtropical-extratropical volcanoes do.

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.

Reservoir Space Evolution of Volcanic Rocks in Deep Songliao Basin, China

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Zheng, M.; Wu, X.; Zheng, M.; HU, J.; Wang, S.

2015-12-01

Recent years, large amount of natural gas has been discovered in volcanic rock of Lower Crataceous of Songliao basin. Volcanic reservoirs have become one of the important target reservoir types of eastern basin of China. In order to study the volcanic reservoirs, we need to know the main factors controlling the reservoir space. By careful obsercation on volcanic drilling core, casting thin sections and statistical analysis of petrophysical properties of volcanic reservoir in Songliao basin, it can be suggested that the igneous rock reservoir in Yingcheng formation of Lower Crataceous is composed of different rock types, such ad rohylite, rohylitic crystal tuff, autoclastic brecciation lava and so on. There are different reservoirs storage space in in various lithological igneous rocks, but they are mainly composed of primary stoma, secondary solution pores and fractures.The evolution of storage space can be divided into 3 stage: the pramary reservoir space,exogenic leaching process and burial diagenesis.During the evolution process, the reservoir space is effected by secondary minerals, tectonic movement and volcanic hydrothermal solution. The pore of volcanic reservoirs can be partially filled by secondary minerals, but also may be dissoluted by other chemical volcanic hydrothermal solution. Therefore, the favorable places for better-quality volcanic reservoirs are the near-crater facies of vocanic apparatus and dissolution zones on the high position of paleo-structures.

Eruptive and environmental processes recorded by diatoms in volcanically-dispersed lake sediments from the Taupo Volcanic Zone, New Zealand

Science.gov (United States)

Harper, Margaret A.; Pledger, Shirley A.; Smith, Euan G. C.; Van Eaton, Alexa; Wilson, Colin J. N.

2015-01-01

Late Pleistocene diatomaceous sediment was widely dispersed along with volcanic ash (tephra) across and beyond New Zealand by the 25.4 ka Oruanui supereruption from Taupo volcano. We present a detailed analysis of the diatom populations in the Oruanui tephra and the newly discovered floras in two other eruptions from the same volcano: the 28.6 ka Okaia and 1.8 ka Taupo eruptions. For comparison, the diatoms were also examined in Late Pleistocene and Holocene lake sediments from the Taupo Volcanic Zone (TVZ). Our study demonstrates how these microfossils provide insights into the lake history of the TVZ since the Last Glacial Maximum. Morphometric analysis of Aulacoseira valve dimensions provides a useful quantitative tool to distinguish environmental and eruptive processes within and between individual tephras. The Oruanui and Okaia diatom species and valve dimensions are highly consistent with a shared volcanic source, paleolake and eruption style (involving large-scale magma-water interaction). They are distinct from lacustrine sediments sourced elsewhere in the TVZ. Correspondence analysis shows that small, intact samples of erupted lake sediment (i.e., lithic clasts in ignimbrite) contain heterogeneous diatom populations, reflecting local variability in species composition of the paleolake and its shallowly-buried sediments. Our analysis also shows a dramatic post-Oruanui supereruption decline in Cyclostephanos novaezelandiae, which likely reflects a combination of (1) reorganisation of the watershed in the aftermath of the eruption, and (2) overall climate warming following the Last Glacial Maximum. This decline is reflected in substantially lower proportions of C. novaezelandiae in the 1.8 ka Taupo eruption deposits, and even fewer in post-1.8 ka sediments from modern (Holocene) Lake Taupo. Our analysis highlights how the excellent preservation of siliceous microfossils in volcanic tephra may fingerprint the volcanic source region and retain a valuable record

[Some reflections on the introduction of family planning into businesses in Cameroon].

Science.gov (United States)

Ngambi Kunga

1990-01-01

Cameroon has announced that it favors family planning as a means of improving family welfare. In the local context, family planning would refer to spacing and to a lesser extent limiting births, as well as combatting infertility. This work argues that, at a time of deep economic and financial crisis for Cameroon and of growing need and demand for family planning services, the introduction of employment-based family planning services could reinforce the family planning activities of the government and private agencies. The work broadly outlines national family planning policy, identifies weaknesses of proposed family planning strategies, and points out the advantages of employment-based services. Cameroon's infant mortality rate of 90/1000 live births and maternal mortality of 420/100,000 are partly related to its very high fertility rate, closely spaced births, and early pregnancy. The national family planning program goal is to promote health and wellbeing by preventing early and unwanted pregnancies and illnesses in high-risk groups. A decline in unwanted births would be achieved through voluntary use of contraception. The main strategy would be an ambitious IEC program to inform the population of the advantages of family planning using mass media, print materials, and interpersonal communication. The general objectives of the IEC program would be to reduce maternal mortality to 300/100,000 and infant mortality from 90 to 70/1000 and increase contraceptive prevalence from 3 to 20% by 1994. Family planning services and commercial distribution centers would be created, taking advantage of existing health facilities wherever possible as well as community based systems of service delivery for the population not yet served by the traditional distribution system. Experience with the IEC strategy in other countries demonstrates that there is a great disproportion between the population touched by IEC and contraceptive prevalence. The strategy would probably be more

Volcanic passive margins: another way to break up continents.

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Geoffroy, L; Burov, E B; Werner, P

2015-10-07

Two major types of passive margins are recognized, i.e. volcanic and non-volcanic, without proposing distinctive mechanisms for their formation. Volcanic passive margins are associated with the extrusion and intrusion of large volumes of magma, predominantly mafic, and represent distinctive features of Larges Igneous Provinces, in which regional fissural volcanism predates localized syn-magmatic break-up of the lithosphere. In contrast with non-volcanic margins, continentward-dipping detachment faults accommodate crustal necking at both conjugate volcanic margins. These faults root on a two-layer deformed ductile crust that appears to be partly of igneous nature. This lower crust is exhumed up to the bottom of the syn-extension extrusives at the outer parts of the margin. Our numerical modelling suggests that strengthening of deep continental crust during early magmatic stages provokes a divergent flow of the ductile lithosphere away from a central continental block, which becomes thinner with time due to the flow-induced mechanical erosion acting at its base. Crustal-scale faults dipping continentward are rooted over this flowing material, thus isolating micro-continents within the future oceanic domain. Pure-shear type deformation affects the bulk lithosphere at VPMs until continental breakup, and the geometry of the margin is closely related to the dynamics of an active and melting mantle.

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.

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

Science.gov (United States)

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

2016-04-01

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

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,…

First volcanic CO2 budget estimate for three actively degassing volcanoes in the Central American Volcanic Arc

Science.gov (United States)

Robidoux, Philippe; Aiuppa, Alessandro; Conde, Vladimir; Galle, Bo; Giudice, Gaetano; Avard, Geoffroy; Muñoz, Angélica

2014-05-01

CO2 is a key chemical tracer for exploring volcanic degassing mechanisms of basaltic magmatic systems (1). The rate of CO2 release from sub-aerial volcanism is monitored via studies on volcanic plumes and fumaroles, but information is still sparse and incomplete for many regions of the globe, including the majority of the volcanoes in the Central American Volcanic Arc (2). Here, we use a combination of remote sensing techniques and in-situ measurements of volcanic gas plumes to provide a first estimate of the CO2 output from three degassing volcanoes in Central America: Turrialba, in Costa Rica, and Telica and San Cristobal, in Nicaragua. During a field campaign in March-April 2013, we obtained (for the three volcanoes) a simultaneous record of SO2 fluxes (from the NOVAC network (3)) and CO2 vs. SO2 concentrations in the near-vent plumes (obtained via a temporary installed fully-automated Multi-GAS instrument (4)). The Multi-GAS time-series allowed to calculate the plume CO2/SO2 ratios for different intervals of time, showing relatively stable gas compositions. Distinct CO2 - SO2 - H2O proportions were observed at the three volcanoes, but still within the range of volcanic arc gas (5). The CO2/SO2 ratios were then multiplied by the SO2 flux in order to derive the CO2 output. At Turrialba, CO2/SO2 ratios fluctuated, between March 12 and 19, between 1.1 and 5.7, and the CO2flux was evaluated at ~1000-1350 t/d (6). At Telica, between March 23 and April 8, a somewhat higher CO2/SO2 ratio was observed (3.3 ± 1.0), although the CO2 flux was evaluated at only ~100-500 t/d (6). At San Cristobal, where observations were taken between April 11 and 15, the CO2/SO2 ratio ranged between 1.8 and 7.4, with a mean CO2 flux of 753 t/d. These measurements contribute refining the current estimates of the total CO2 output from the Central American Volcanic Arc (7). Symonds, R.B. et al., (2001). J. Volcanol. Geotherm. Res., 108, 303-341 Burton, M. R. et al. (2013). Reviews in

The volcanism of the western part of the Los Frailes Meseta (Bolivia): a representative example of the Andean volcanism since the Upper Oligocene

International Nuclear Information System (INIS)

Leroy, L.; Jimenez, N.

1996-01-01

The Los Frailes Meseta (Bolivia) is one of the large tertiary ignimbritic fields of the inner volcanic arc from Central Andes (Central Volcanic Zone. CVZ), in contact zone between the Altiplano to the west and the Eastern Cordillera to the east. Field observations and mineralogical and geochemical studies (major and trace elements) lead to distinguish two types of volcanism in the western border to the Meseta. During the Middle Miocene and Pliocene, the volcanic activity can be subdivided into three pyroclastic emission cycles, the Larco, Coroma and Pliocene ignimbrites, the first two being separated by the Quechua 2 orogeny. All these ignimbrites are very similar and correspond to peraluminous rhyolites to rhyodacites. In the studies area, the Coroma cycle is the only one where an ignimbrite-less evolved resurgent dome association can be observed. Beside these ignimbrites, isolated small lava flows and domes overlay and/or intrude all the other formations. They are meta-aluminous lavas with a shoshonitic affinity. A quaternary age can be attributed to his second volcanism. These two volcanic types are well-known in the CVZ and are related to the different deformation stages, either compressional or extensional, which occur alternately in the Cordillera since 26 Ma. (authors). 61 refs., 12 figs., 3 tabs

Evidence for volcanism in NW Ishtar Terra, Venus

International Nuclear Information System (INIS)

Gaddis, L.; Greeley, R.

1989-01-01

Venera 15/16 radar data for an area in NW Ishtar Terra, Venus, show an area with moderate radar return and a smooth textured surface which embays low lying areas of the surrounding mountainous terrain. Although this unit may be an extension of the lava plains of Lakshmi Planum to the southeast, detailed study suggests a separate volcanic center in NW Ishtar Terra. Lakshmi Planum, on the Ishtar Terra highland, exhibits major volcanic and tectonic features. On the Venera radar image radar brightness is influenced by slope and roughness; radar-facing slopes (east-facing) and rough surfaces (approx. 8 cm average relief) are bright, while west-facing slopes and smooth surfaces are dark. A series of semi-circular features, apparently topographic depressions, do not conform in orientation to major structural trends in this region of NW Ishtar Terra. The large depression in NW Ishtar Terra is similar to the calderas of Colette and Sacajawea Paterae, as all three structures are large irregular depressions. NW Ishtar Terra appears to be the site of a volcanic center with a complex caldera structure, possibly more than one eruptive vent, and associated lobed flows at lower elevations. The morphologic similarity between this volcanic center and those of Colette and Sacajawea suggests that centralized eruptions have been the dominant form of volcanism in Ishtar. The location of this volcanic center at the intersection of two major compressional mountain belts and the large size of the calders (with an inferred larg/deep magma source) support a crustal thickening/melting rather than a hot-spot origin for these magmas

Geochemistry of volcanic series of Aragats province

International Nuclear Information System (INIS)

Meliksetyan, Kh.B.

2012-01-01

In this contribution we discuss geochemical and isotope characteristics of volcanism of the Aragats volcanic province and possible petrogenetical models of magma generation in collision zone of Armenian highland. We talk about combination of some specific features of collision related volcanism such as dry and high temperature conditions of magma generation, that demonstrate some similarities to intraplate-like petrogenesis and presence of mantle source enriched by earlier subductions, indicative to island-arc type magma generation models. Based on comprehensive analysis of isotope and geochemical data and some published models of magma generation beneath Aragats we lead to a petrogenetic model of origin of Aragats system to be a result of magma mixture between mantle originated mafic magma with felsic, adakite-type magmas

Rationing hepatitis C treatment in the context of austerity policies in France and Cameroon: A transnational perspective on the pharmaceuticalization of healthcare systems.

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Chabrol, Fanny; David, Pierre-Marie; Krikorian, Gaëlle

2017-08-01

New powerful drugs against hepatitis C can cure the disease, but they are not widely distributed because their exorbitant prices are destabilizing healthcare systems in both African and European countries. This article takes access to hepatitis C treatments since 2013 in France and in Cameroon as a lens to analyze the rationing of pharmaceutical treatments in relation to recent transformations of health systems. Access to these treatments is analyzed thanks to ethnographic observation and interviews lead in Paris and Yaoundé, with patients, associations, health professionals and public health experts. In Cameroon, rationing takes place through various layers of socio-economic restrictions, and no patient organization advocates for hepatitis treatment. In France, access to hepatitis C treatments has become politicized, and collective mobilizations have denounced rationing as a threat to the promise of universal social security. In this study, we examine Africa's long experience with rationing in the context of structural adjustment, and we bring together experiences in France and Cameroon. This article analyses the phenomenon of the pharmaceuticalization of healthcare systems, that is to say the growing use of pharmaceuticals in healthcare systems, by documenting the social and political construction of scarcity. Indeed, whereas pharmaceuticalization is a concept that has often been used in situations of drugs abundance, a parallel analysis of rationing highlights a political economy of pharmaceuticals that shapes public health debates and policies according to an economy of scarcity, especially in times of austerity. Copyright © 2017. Published by Elsevier Ltd.

Population trends of antelopes in Waza National Park (Cameroon) from 1960 to 2001: The interacting effects of rainfall, flooding and human interventions

NARCIS (Netherlands)

Scholte, P.; Adam, S.; Serge, B.K.

2007-01-01

Antelopes are prominent wildlife in Waza National Park, situated in Sahelo-Sudanian Cameroon, which has witnessed dramatic changes in rainfall and flooding. To assess their impacts, we reviewed 26 aerial and terrestrial surveys, comprising total, transect and localized counts. Estimated numbers of

Global monsoon precipitation responses to large volcanic eruptions

Science.gov (United States)

Liu, Fei; Chai, Jing; Wang, Bin; Liu, Jian; Zhang, Xiao; Wang, Zhiyuan

2016-01-01

Climate variation of global monsoon (GM) precipitation involves both internal feedback and external forcing. Here, we focus on strong volcanic forcing since large eruptions are known to be a dominant mechanism in natural climate change. It is not known whether large volcanoes erupted at different latitudes have distinctive effects on the monsoon in the Northern Hemisphere (NH) and the Southern Hemisphere (SH). We address this issue using a 1500-year volcanic sensitivity simulation by the Community Earth System Model version 1.0 (CESM1). Volcanoes are classified into three types based on their meridional aerosol distributions: NH volcanoes, SH volcanoes and equatorial volcanoes. Using the model simulation, we discover that the GM precipitation in one hemisphere is enhanced significantly by the remote volcanic forcing occurring in the other hemisphere. This remote volcanic forcing-induced intensification is mainly through circulation change rather than moisture content change. In addition, the NH volcanic eruptions are more efficient in reducing the NH monsoon precipitation than the equatorial ones, and so do the SH eruptions in weakening the SH monsoon, because the equatorial eruptions, despite reducing moisture content, have weaker effects in weakening the off-equatorial monsoon circulation than the subtropical-extratropical volcanoes do. PMID:27063141

Radon gas as a tracer for volcanic processes

International Nuclear Information System (INIS)

Thomas, D.M.

1990-01-01

Radon emissions from volcanic systems have been under investigation for several decades. Soil gas and groundwater radon activities have been used to map faults and to characterize geothermal systems, and measurements of atmospheric radon and radon daughter concentrations have been used to estimate the volume of magma chambers feeding active eruptions. Several studies have also shown that temporal variations in radon concentration have been associated with the onset of volcanic eruptions or changes in the rates or character of an eruption. Some of these studies have been able to clearly define the cause of the radon anomalies but others have proposed models of radon emission and transport that are not well supported by the known physical and chemical processes that occur in a volcanic system. In order to better characterize the processes that control radon activities in volcanic systems, it is recommended that future radon monitoring programs attempt to maintain continuous recording of radon activities; individual radon measurements should be made over the shortest time intervals possible that are consistent with acceptable counting statistics and geophysical, meteorological, and hydrological parameters should be measured in order to better define the physical processes that affect radon activities in volcanic systems. (author). 63 refs

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.

Mapping of Schistosomiasis and Soil-Transmitted Helminthiasis in the Regions of Centre, East and West Cameroon

Science.gov (United States)

Tchuem Tchuenté, Louis-Albert; Kamwa Ngassam, Romuald Isaka; Sumo, Laurentine; Ngassam, Pierre; Dongmo Noumedem, Calvine; Nzu, Deguy D'or Luogbou; Dankoni, Esther; Kenfack, Christian Mérimé; Gipwe, Nestor Feussom; Akame, Julie; Tarini, Ann; Zhang, Yaobi; Angwafo, Fru Fobuzski

2012-01-01

Background Schistosomiasis and soil-transmitted helminthiasis (STH) are widely distributed in Cameroon. Although mass drug administration (MDA) of mebendazole is implemented nationwide, treatment with praziquantel was so far limited to the three northern regions and few health districts in the southern part of Cameroon, based on previous mapping conducted 25 years ago. To update the disease distribution map and determine where treatment with praziquantel should be extended, mapping surveys were conducted in three of the seven southern regions of Cameroon, i.e. Centre, East and West. Methodology Parasitological surveys were conducted in April–May 2010 in selected schools in all 63 health districts of the three targeted regions, using appropriate research methodologies, i.e. Kato-Katz and urine filtration. Principal Findings The results showed significant variation of schistosomiasis and STH prevalence between schools, villages, districts and regions. Schistosoma mansoni was the most prevalent schistosome species, with an overall prevalence of 5.53%, followed by S. haematobium (1.72%) and S. guineensis (0.14%). The overall prevalence of schistosomiasis across the three regions was 7.31% (95% CI: 6.86–7.77%). The prevalence for Ascaris lumbricoides was 11.48 (95% CI: 10.93–12.04%), Trichuris trichiura 18.22% (95% CI: 17.56–18.90%) and hookworms 1.55% (95% CI: 1.35–1.78%), with an overall STH prevalence of 24.10% (95% CI: 23.36–24.85%) across the three regions. STH was more prevalent in the East region (46.57%; 95% CI: 44.41–48.75%) in comparison to the Centre (25.12; 95% CI: 24.10–26.17%) and West (10.49%; 95% CI: 9.57–11.51%) regions. Conclusions/Significance In comparison to previous data, the results showed an increase of schistosomiasis transmission in several health districts, whereas there was a significant decline of STH infections. Based on the prevalence data, the continuation of annual or bi-annual MDA for STH is recommended, as well as an

Production of low molecular weight hydrocarbons by volcanic eruptions on early Mars.

Science.gov (United States)

Segura, Antígona; Navarro-González, Rafael

2005-10-01

Methane and other larger hydrocarbons have been proposed as possible greenhouse gases on early Mars. In this work we explore if volcanic processes may have been a source for such molecules based on theoretical and experimental considerations. Geologic evidence and numerical simulations indicate that explosive volcanism was widely distributed throughout Mars. Volcanic lightning is typically produced in such explosive volcanism. Therefore this geologic setting was studied to determine if lightning could be a source for hydrocarbons in volcanic plumes. Volcanic lightning was simulated by focusing a high-energy infrared laser beam inside of a Pyrex reactor that contained the proposed volcanic gas mixture composed of 64% CH(4), 24% H(2), 10% H(2)O and 2% N(2), according to an accretion model and the nitrogen content measured in Martian meteorites. The analysis of products was performed by gas chromatography coupled to infrared and mass spectroscopy. Eleven hydrocarbons were identified among the products, of which acetylene (C(2)H(2)) was the most abundant. A thermochemical model was used to determine which hydrocarbons could arise only from volcanic heat. In this case, acetylene and ethylene are formed at magmatic temperatures. Our results indicate that explosive volcanism may have injected into the atmosphere of early Mars approximately 6 x 10(12) g yr(-1) of acetylene, and approximately 2 x 10(12) g yr(-1) of 1,3-butadiyne, both produced by volcanic lightning, approximately 5 x 10(11) g yr(-1) of ethylene produced by volcanic heat, and 10(13) g yr(-1) of methane.

Participatory Resource Mapping for Livelihood Values Derived from the Forest in Ekondo-Titi Subregion, Cameroon: A Gender Analysis

Directory of Open Access Journals (Sweden)

Daniel B. Etongo

2012-01-01

Full Text Available Increasingly, the multiplicity of products, services, and values, and the diversity of interests from different resource users and groups, is being acknowledged as vital for sustainable use. This calls for a shift from protection to sustainable use and to resource-user focus. The aim of this study is to identify the spatial occurrence of livelihood values through participatory resource mapping, their changes over time and alternatives for sustainable management. A participatory resource mapping study was conducted with local community, including important stakeholders in Ekondo-Titi subregion of Cameroon. The research technique which focused on gender revealed different patterns of forest resources and changes on the landscape. The study concludes that the importance of resources varies between men and women in Ekondo-Titi subregion of Cameroon, implying that resources may have multipurpose functions, but its exact role depends on the needs of the user groups that utilize them. The divergence of opinion on certain resources is a clear indication of preferences that are gender motivated. The study also revealed that the greatest impact of land use change is the conversion of forest land into agriculture.

Strike-slip pull-apart process and emplacement of Xiangshan uranium-producing volcanic basin

International Nuclear Information System (INIS)

Qiu Aijin; Guo Lingzhi; Shu Liangshu

2001-01-01

Xiangshan volcanic basin is one of the famous uranium-producing volcanic basins in China. Emplacement mechanism of Xiangshan uranium-producing volcanic basin is discussed on the basis of the latest research achievements of deep geology in Xiangshan area and the theory of continental dynamics. The study shows that volcanic activity in Xiangshan volcanic basin may be divided into two cycles, and its emplacement is controlled by strike-ship pull-apart process originated from the deep regional faults. Volcanic apparatus in the first cycle was emplaced in EW-trending structure activated by clockwise strike-slipping of NE-trending deep fault, forming the EW-trending fissure-type volcanic effusion belt. Volcanic apparatus in the second cycle was emplaced at junction points of SN-trending pull-apart structure activated by sinistral strike-slipping of NE-trending deep faults and EW-trending basement faults causing the center-type volcanic magma effusion and extrusion. Moreover, the formation mechanism of large-rich uranium deposits is discussed as well

Volcanic gas emissions and degassing dynamics at Ubinas and Sabancaya volcanoes; implications for the volatile budget of the central volcanic zone

Science.gov (United States)

Moussallam, Yves; Tamburello, Giancarlo; Peters, Nial; Apaza, Fredy; Schipper, C. Ian; Curtis, Aaron; Aiuppa, Alessandro; Masias, Pablo; Boichu, Marie; Bauduin, Sophie; Barnie, Talfan; Bani, Philipson; Giudice, Gaetano; Moussallam, Manuel

2017-09-01

Emission of volcanic gas is thought to be the dominant process by which volatiles transit from the deep earth to the atmosphere. Volcanic gas emissions, remain poorly constrained, and volcanoes of Peru are entirely absent from the current global dataset. In Peru, Sabancaya and Ubinas volcanoes are by far the largest sources of volcanic gas. Here, we report the first measurements of the compositions and fluxes of volcanic gases emitted from these volcanoes. The measurements were acquired in November 2015. We determined an average SO2 flux of 15.3 ± 2.3 kg s- 1 (1325-ton day- 1) at Sabancaya and of 11.4 ± 3.9 kg s- 1 (988-ton day- 1) at Ubinas using scanning ultraviolet spectroscopy and dual UV camera systems. In-situ Multi-GAS analyses yield molar proportions of H2O, CO2, SO2, H2S and H2 gases of 73, 15, 10 1.15 and 0.15 mol% at Sabancaya and of 96, 2.2, 1.2 and 0.05 mol% for H2O, CO2, SO2 and H2S at Ubinas. Together, these data imply cumulative fluxes for both volcanoes of 282, 30, 27, 1.2 and 0.01 kg s- 1 of H2O, CO2, SO2, H2S and H2 respectively. Sabancaya and Ubinas volcanoes together contribute about 60% of the total CO2 emissions from the Central Volcanic zone, and dominate by far the total revised volatile budget of the entire Central Volcanic Zone of the Andes.

Nature and origin of secondary mineral coatings on volcanic rocks of the Black Mountain, Stonewall Mountain, and Kane Springs Wash volcanic centers, southern, Nevada

Science.gov (United States)

Taranik, James V.; Hsu, Liang C.; Spatz, David M.; Chenevey, Michael J.

1989-01-01

The following subject areas are covered: (1) genetic, spectral, and LANDSAT Thematic Mapper imagery relationship between desert varnish and tertiary volcanic host rocks, southern Nevada; (2) reconnaissance geologic mapping of the Kane Springs Wash Volcanic Center, Lincoln County, Nevada, using multispectral thermal infrared imagery; (3) interregional comparisons of desert varnish; and (4) airborne scanner (GERIS) imagery of the Kane Springs Wash Volcanic Center, Lincoln County, Nevada.

Determination of multiple mycotoxins levels in poultry feeds from Cameroon.

Science.gov (United States)

Abia, Wilfred Angie; Simo, Grace Nella; Warth, Benedikt; Sulyok, Michael; Krska, Rudolf; Tchana, Angele; Moundipa, Paul Fewou

2013-02-01

For the first time in Cameroon, this paper reports on multiple mycotoxins occurrences in poultry feeds. Twenty feed samples collected from different poultry farms were analyzed for 320 fungal metabolites by liquid chromatography electrospray ionization tandem mass spectrometry. Results showed feeds contamination by 68 metabolites including 18 mycotoxins/metabolites currently regulated in the European Union such as fumonisins B1 (FB1), B2, and B3; deoxynevalenol (DON); and beta-zearalenol recovered in all samples. FB1 reported highest FB mean level of 468 (range 16-1930) microg kg(-1). Levels of DON and ZEN were mostly concentrated in feeds from western-highlands conversely for FBs and aflatoxins concentrations in Yaounde. Aflatoxin B1 mean level of 40 microg kg(-1) exceeded the worldwide permitted limit for aflatoxins in feed and generally inversely proportional to weight gain in chicken.

Compositional Differences between Felsic Volcanic rocks from the ...

African Journals Online (AJOL)

The elemental and Sr-Nd isotopic compositions of the volcanic rocks suggest that fractional crystallization from differing basic parents accompanied by a limited assimilation (AFC) was the dominant process controlling the genesis of the MER felsic volcanic rocks. Keywords: Ethiopia; Northern Main Ethiopian Rift; Bimodal ...

Eruptive history of the Elysium volcanic province of Mars

International Nuclear Information System (INIS)

Tanaka, K.L.; Scott, D.H.

1987-01-01

New geologic mapping of the Elysium volcanic province at 1:2,000,000 scale and crater counts provide a basis for describing its overall eruptive history. Four stages are listed and described in order of their relative age. They are also distinguished by eruption style and location. Stage 1: Central volcanism at Hecates and Albor Tholi. Stage 2: Shield and complex volcanism at Elysium Mons and Elysium Fossae. Stage 3: Rille volcanism at Elysium Fossae and Utopia Planitia. Stage 4: Flood lava and pyroclastic eruptions at Hecates Tholus and Elysium Mons. Tectonic and channeling activity in the Elysium region is intimately associated with volcanism. Recent work indicates that isostatic uplift of Tharsis, loading by Elysium Mons, and flexural uplift of the Elysium rise produced the stresses responsible for the fracturing and wrinkle-ridge formation in the region. Coeval faulting and channel formation almost certainly occurred in the pertinent areas in Stages 2 to 4. Older faults east of the lava flows and channels on Hecates Tholus may be coeval with Stage 1

Investigation of a possible yellow fever epidemic and serosurvey for flavivirus infections in northern Cameroon, 1984

OpenAIRE

Tsai, T. F.; Lazuick, J. S.; Ngah, R. W.; Mafiamba, P. C.; Quincke, G.; Monath, T. P.

1987-01-01

A cluster of fatal hepatitis cases in northern Cameroon in 1984 stimulated a field investigation to rule out an epidemic of yellow fever. A serosurvey of villages in the extreme north of the country, in a Sudan savanna (SS) phytogeographical zone, disclosed no evidence of recent yellow fever infection. However, further south, in a Guinea savanna (GS) phytogeographical zone, serological evidence was found of endemic yellow fever virus transmission. The results indicate a potential for epidemic...

Observations of volcanic plumes using small balloon soundings

Science.gov (United States)

Voemel, H.

2015-12-01

Eruptions of volcanoes are very difficult to predict and for practical purposes may occur at any time. Any observing system intending to observe volcanic eruptions has to be ready at any time. Due to transport time scales, emissions of large volcanic eruptions, in particular injections into the stratosphere, may be detected at locations far from the volcano within days to weeks after the eruption. These emissions may be observed using small balloon soundings at dedicated sites. Here we present observations of particles of the Icelandic Grimsvotn eruption at the Meteorological Observatory Lindenberg, Germany in the months following the eruption and observations of opportunity of other volcanic particle events. We also present observations of the emissions of SO2 from the Turrialba volcano at San Jose, Costa Rica. We argue that dedicated sites for routine observations of the clean and perturbed atmosphere using small sounding balloons are an important element in the detection and quantification of emissions from future volcanic eruptions.

The Role of Volcanic Activity in Climate and Global Change

KAUST Repository

Stenchikov, Georgiy L.

2015-09-23

Explosive volcanic eruptions are magnificent events that in many ways affect the Earth\\'s natural processes and climate. They cause sporadic perturbations of the planet\\'s energy balance, activating complex climate feedbacks and providing unique opportunities to better quantify those processes. We know that explosive eruptions cause cooling in the atmosphere for a few years, but we have just recently realized that volcanic signals can be seen in the subsurface ocean for decades. The volcanic forcing of the previous two centuries offsets the ocean heat uptake and diminishes global warming by about 30%. The explosive volcanism of the twenty-first century is unlikely to either cause any significant climate signal or to delay the pace of global warming. The recent interest in dynamic, microphysical, chemical, and climate impacts of volcanic eruptions is also excited by the fact that these impacts provide a natural analogue for climate geoengineering schemes involving deliberate development of an artificial aerosol layer in the lower stratosphere to counteract global warming. In this chapter we aim to discuss these recently discovered volcanic effects and specifically pay attention to how we can learn about the hidden Earth-system mechanisms activated by explosive volcanic eruptions. To demonstrate these effects we use our own model results when possible along with available observations, as well as review closely related recent publications.

The monogenetic Bayuda Volcanic Field, Sudan - New insights into geology and volcanic morphology

Science.gov (United States)

Lenhardt, Nils; Borah, Suranjana B.; Lenhardt, Sukanya Z.; Bumby, Adam J.; Ibinoof, Montasir A.; Salih, Salih A.

2018-05-01

The small monogenetic Bayuda Volcanic Field (BVF; 480 km2), comprising at least 53 cinder cones and 15 maar volcanoes in the Bayuda desert of northern Sudan is one of a few barely studied volcanic occurrences of Quaternary age in Sudan. The exact age of the BVF and the duration of volcanic activity has not yet been determined. Furthermore, not much is known about the eruptional mechanisms and the related magmatic and tectonic processes that led to the formation of the volcanic field. In the framework of a larger project focusing on these points it is the purpose of this contribution to provide a first account of the general geology of the BVF volcanoes as well as a first description of a general stratigraphy, including a first description of their morphological characteristics. This was done by means of fieldwork, including detailed rock descriptions, as well as the analysis of satellite images (SRTM dataset at 30 m spatial resolution). The BVF cinder cones are dominated by scoracious lapilli tephra units, emplaced mainly by pyroclastic fallout from Strombolian eruptions. Many cones are breached and are associated with lava flows. The subordinate phreatomagmatism represented by maar volcanoes suggests the presence of ground and/or shallow surface water during some of the eruptions. The deposits constituting the rims around the maar volcanoes are interpreted as having mostly formed due to pyroclastic surges. Many of the tephra rings around the maars are underlain by thick older lava flows. These are inferred to be the horizons where rising magma interacted with groundwater. The existence of phreatomagmatic deposits may point to a time of eruptive activity during a phase with wetter conditions and therefore higher groundwater levels than those encountered historically. This is supported by field observations as well as the morphological analysis, providing evidence for relatively high degrees of alteration of the BVF volcanoes and therefore older eruption ages as

Critical review of a new volcanic eruption chronology

Science.gov (United States)

Neuhäuser, Dagmar L.; Neuhäuser, Ralph

2016-04-01

Sigl. et al. (2015, Nature) present historical evidence for 32 volcanic eruptions to evaluate their new polar ice core 10-Be chronology - 24 are dated within three years of sulfur layers in polar ice. Most of them can be interpreted as weather phenomena (Babylonia: disk of sun like moon, reported for only one day, e.g. extinction due to clouds), Chinese sunspot reports (pellet, black vapor, etc.), solar eclipses, normal ice-halos and coronae (ring, bow, etc.), one aurora (redness), red suns due to mist drops in wet fog or fire-smoke, etc. Volcanic dust may facilitate detections of sunspots and formation of Bishop's ring, but tend to inhibit ice-halos, which are otherwise often reported in chronicles. We are left with three reports possibly indicating volcanic eruptions, namely fulfilling genuine criteria for atmospheric disturbances due to volcanic dust, e.g. bluish or faint sun, orange sky, or fainting of stars for months (BCE 208, 44-42, and 32). Among the volcanic eruptions used to fix the chronology (CE 536, 626, 939, 1257), the reports cited for the 930s deal only with 1-2 days, at least one reports an eclipse. In the new chronology, there is a sulfur detection eight years after the Vesuvius eruption, but none in CE 79. It may appear surprising that, from BCE 500 to 1, all five northern sulfur peaks labeled in figure 2 in Sigl et al. are systematically later by 2-4 years than the (corresponding?) southern peaks, while all five southern peaks from CE 100 to 600 labeled in figure 2 are systematically later by 1-4 years than the (corresponding?) northern peaks. Furthermore, in most of their six strongest volcanic eruptions, temperatures decreased years before their sulfur dating - correlated with weak solar activity as seen in radiocarbon, so that volcanic climate forcing appears dubious here. Also, their 10-Be peaks at CE 775 and 994 are neither significant nor certain in dating.

Effects of Volcanic Eruptions on Stratospheric Ozone Recovery

Science.gov (United States)

Rosenfield, Joan E.

2002-01-01

The effects of the stratospheric sulfate aerosol layer associated with the Mt. Pinatubo volcano and future volcanic eruptions on the recovery of the ozone layer is studied with an interactive two-dimensional photochemical model. The time varying chlorine loading and the stratospheric cooling due to increasing carbon dioxide have been taken into account. The computed ozone and temperature changes associated with the Mt. Pinatubo eruption in 1991 agree well with observations. Long model runs out to the year 2050 have been carried out, in which volcanoes having the characteristics of the Mount Pinatubo volcano were erupted in the model at 10-year intervals starting in the year 2010. Compared to a non-volcanic run using background aerosol loading, transient reductions of globally averaged column ozone of 2-3 percent were computed as a result of each of these eruptions, with the ozone recovering to that computed for the non-volcanic case in about 5 years after the eruption. Computed springtime Arctic column ozone losses of from 10 to 18 percent also recovered to the non-volcanic case within 5 years. These results suggest that the long-term recovery of ozone would not be strongly affected by infrequent volcanic eruptions with a sulfur loading approximating Mt. Pinatubo. Sensitivity studies in which the Arctic lower stratosphere was forced to be 4 K and 10 K colder resulted in transient ozone losses of which also recovered to the non-volcanic case in 5 years. A case in which a volcano five times Mt. Pinatubo was erupted in the year 2010 led to maximum springtime column ozone losses of 45 percent which took 10 years to recover to the background case. Finally, in order to simulate a situation in which frequent smaller volcanic eruptions result in increasing the background sulfate loading, a simulation was made in which the background aerosol was increased by 10 percent per year. This resulted in a delay of the recovery of column ozone to 1980 values of more than 10 years.

Volcanic Ash Data Assimilation System for Atmospheric Transport Model

Science.gov (United States)

Ishii, K.; Shimbori, T.; Sato, E.; Tokumoto, T.; Hayashi, Y.; Hashimoto, A.

2017-12-01

The Japan Meteorological Agency (JMA) has two operations for volcanic ash forecasts, which are Volcanic Ash Fall Forecast (VAFF) and Volcanic Ash Advisory (VAA). In these operations, the forecasts are calculated by atmospheric transport models including the advection process, the turbulent diffusion process, the gravitational fall process and the deposition process (wet/dry). The initial distribution of volcanic ash in the models is the most important but uncertain factor. In operations, the model of Suzuki (1983) with many empirical assumptions is adopted to the initial distribution. This adversely affects the reconstruction of actual eruption plumes.We are developing a volcanic ash data assimilation system using weather radars and meteorological satellite observation, in order to improve the initial distribution of the atmospheric transport models. Our data assimilation system is based on the three-dimensional variational data assimilation method (3D-Var). Analysis variables are ash concentration and size distribution parameters which are mutually independent. The radar observation is expected to provide three-dimensional parameters such as ash concentration and parameters of ash particle size distribution. On the other hand, the satellite observation is anticipated to provide two-dimensional parameters of ash clouds such as mass loading, top height and particle effective radius. In this study, we estimate the thickness of ash clouds using vertical wind shear of JMA numerical weather prediction, and apply for the volcanic ash data assimilation system.

Volcanic risk perception of young people in the urban areas of Vesuvius: Comparisons with other volcanic areas and implications for emergency management

Science.gov (United States)

Carlino, S.; Somma, R.; Mayberry, G.C.

2008-01-01

More than 600 000 people are exposed to volcanic risk in the urban areas near the volcano, Vesuvius, and may need to be evacuated if there is renewed volcanic activity. The success of a future evacuation will strongly depend on the level of risk perception and preparedness of the at-risk communities during the current period of quiescence. The volcanic risk perception and preparedness of young people is of particular importance because hazard education programs in schools have been shown to increase the clarity of risk perception and students often share their knowledge with their parents. In order to evaluate young people's risk perception and preparedness for a volcanic crisis, a multiple choice questionnaire was distributed to 400 high-school students in three municipalities located close to the volcano. The overall results suggest that despite a 60-year period of quiescence at Vesuvius, the interviewed students have an accurate perception of the level of volcanic risk. On the other hand, the respondents demonstrate a clear lack of understanding of volcanic processes and their related hazards. Also, the interviewed students show high levels of fear, poor perceived ability to protect themselves from the effects of a future eruption, and insufficient knowledge of the National Emergency Plan for Vesuvian Area (NEPVA). The latter result suggests that in comparison with volcanic crises in other regions, during a future eruption of Vesuvius, there may not be enough time to educate the large number of people living near the volcano about how to appropriately respond. The inadequate risk education and preparedness of respondents implies that a strong effort is needed to improve communication strategies in order to facilitate successful evacuations. Therefore, it is important to take advantage of the present period of quiescence at Vesuvius to improve the accuracy of risk perception of youth in local communities. ?? 2008.

Pacific seamount volcanism in space and time

Science.gov (United States)

Hillier, J. K.

2007-02-01

Seamounts constitute some of the most direct evidence about intraplate volcanism. As such, when seamounts formed and into which tectonic setting they erupted (i.e. on-ridge or off-ridge) are a useful reflection of how the properties of the lithosphere interact with magma generation in the fluid mantle beneath. Proportionately few seamounts are radiometrically dated however, and these tend to be recently active. In order to more representatively sample and better understand Pacific seamount volcanism this paper estimates the eruption ages (tvolc) of 2706 volcanoes via automated estimates of lithospheric strength. Lithospheric strength (GTRrel) is deduced from the ratio of gravity to topography above the summits of volcanoes, and is shown to correlate with seafloor age at the time of volcanic loading (Δt) at 61 sites where radiometric constraints upon Δt exist. A trend of fits data for these 61, and with seafloor age (tsf) known, can date the 2706 volcanoes; tvolc = tsf - Δt. Widespread recurrences of volcanism proximal to older features (e.g. the Cook-Austral alignment in French Polynesia) suggest that the lithosphere exerts a significant element of control upon the location of volcanism, and that magmatic throughput leaves the lithosphere more susceptible to the passage of future melts. Observations also prompt speculation that: the Tavara seamounts share morphological characteristics and isostatic compensation state with the Musicians, and probably formed similarly; the Easter Island chain may be a modern analogy to the Cross-Lines; a Musicians - South Hawaiian seamounts alignment may be deflecting the Hawaiian hotspot trace.

The interactions of human mobility and farming systems and impacts on biodiversity and soil quality in the Western Highlands of Cameroon

NARCIS (Netherlands)

Tankou, Christopher Mubeteneh

2013-01-01

Population growth and the drop in the returns from the major cash crop (coffee) for small farmers are the main drivers that have influenced the farming systems and mobility of farmers in the Western Highlands of Cameroon (WHC). The main objective of this research activity was to determine the

Stratigraphical sequence and geochronology of the volcanic rock series in caifang basin, south jiangxi

International Nuclear Information System (INIS)

Xu Xunsheng; Wu Jianhua

2010-01-01

The late Mesozoic volcanic rocks in Jiangxi constitute two volcanic belts: the northern is Xiajiang-Guangfeng volcanic belt, the volcanic rocks series belong to one volcano cycle and named Wuyi group which is subdivided into three formations (Shuangfengling formation, Ehuling formation and Shixi formation); the southern is Sannan-Xunwu volcanic belt, the volcanic rocks series in Caifang basin which locates on Sannan-Xunwu volcanic belt also belong to only one volcano cycle. It can be subdivided into two lithology and lithofacies units (upper and lower): the lower unit consists of sedimentary rocks and associated with a subordinate amount of volcanic rocks, it belongs to erupt-deposit facies which is the product of early volcanic stage; the upper unit is mostly composed of volcanic rocks, it belongs to erupt facies that is the volcanic eruption product. SHRIMP zircon U-Pb age of rhyolite? which locates at the top of the upper unit is 130.79 ± 0.73) Ma. According to the new International Stratigraphic Chart, the boundary of Jurassic and Cretaceous is (145.4 ± 4.0) Ma, so the age shows that the geologic period of Caifang volcanic rocks series is early Early Cretaceous epoch. On the basis of lithological correlation, lithofacies and stratigraphic horizon analysis, the volcanic rock series in Caifang basin fall under Wuyi group, and the lower unit could be incorporated into Shuangfengling formation, the upper unit could be incorporated into Ehuling formation. The subdivision of sequence and the determination of geochronology of the volcanic rock series in Caifang basin provide some references for the study of the late Mesozoic volcanic rocks series of the Sannan-Xunwu volcanic belt. (authors)

Volcanism at 1.45 Ma within the Yellowstone Volcanic Field, United States

Science.gov (United States)

Rivera, Tiffany A.; Furlong, Ryan; Vincent, Jaime; Gardiner, Stephanie; Jicha, Brian R.; Schmitz, Mark D.; Lippert, Peter C.

2018-05-01

Rhyolitic volcanism in the Yellowstone Volcanic Field has spanned over two million years and consisted of both explosive caldera-forming eruptions and smaller effusive flows and domes. Effusive eruptions have been documented preceding and following caldera-forming eruptions, however the temporal and petrogenetic relationships of these magmas to the caldera-forming eruptions are relatively unknown. Here we present new 40Ar/39Ar dates for four small-volume eruptions located on the western rim of the second-cycle caldera, the source of the 1.300 ± 0.001 Ma Mesa Falls Tuff. We supplement our new eruption ages with whole rock major and trace element chemistry, Pb isotopic ratios of feldspar, and paleomagnetic and rock magnetic analyses. Eruption ages for the effusive Green Canyon Flow (1.299 ± 0.002 Ma) and Moonshine Mountain Dome (1.302 ± 0.003 Ma) are in close temporal proximity to the eruption age of the Mesa Falls Tuff. In contrast, our results indicate a period of volcanism at ca 1.45 Ma within the Yellowstone Volcanic Field, including the eruption of the Bishop Mountain Flow (1.458 ± 0.002 Ma) and Tuff of Lyle Spring (1.450 ± 0.003 Ma). These high-silica rhyolites are chemically and isotopically distinct from the Mesa Falls Tuff and related 1.3 Ma effusive eruptions. The 40Ar/39Ar data from the Tuff of Lyle Spring demonstrate significant antecrystic inheritance, prevalent within the upper welded ash-flow tuff matrix, and minimal within individual pumice. Antecrysts are up to 20 kyr older than the eruption, with subpopulations of grains occurring every few thousand years. We interpret these results as an indicator for the timing of magmatic pulses into a growing magmatic system that would ultimately erupt the Tuff of Lyle Spring, and which we more broadly interpret as the tempo of crustal accumulation associated with bimodal magmatism. We propose a system whereby chemically, isotopically, and temporally distinct, isolated small-volume magma batches are

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

Directory of Open Access Journals (Sweden)

Tord Kjellstrom

2010-11-01

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

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.

The Te Rere and Okareka eruptive episodes : Okataina Volcanic Centre, Taupo Volcanic Zone, New Zealand

International Nuclear Information System (INIS)

Nairn, I.A.

1992-01-01

The Te Rere and Okareka eruptive episodes occurred within the Okataina Volcanic Centre at c. 21 000 and 18 000 yr B.P., respectively. The widespread rhyolitic pumice fall deposits of Te Rere Ash (volume 5 km 3 ) and Okareka Ash (6 km 3 ) are only rarely exposed in near-source areas, and locations of their vent areas have been uncertain. New exposures and petrographic and chemical analyses show that the Te Rere episode eruptions occurred from multiple vents, up to 20 km apart, on the Haroharo linear vent zone. The Okareka episode eruptions occurred from vents since buried beneath the Tarawera volcanic massif. Eruption of the rhyolitic Okareka pumice fall was immediately preceded by a small basaltic scoria eruption, apparently from vents close to those for the following rhyolite eruptions. Dacitic mixed pumices scattered within the rhyolite pumice layers immediately overlying the scoria were formed by mixing of the basalt and rhyolite magmas. The Te Rere and Okareka pyroclastic eruptions were both followed by extrusion of voluminous rhyolite lavas. These eruptive episodes mark the commencement of growth of the present-day Haroharo and Tarawera volcanic complexes. (author). 27 refs., 14 figs., 6 tabs

Knowledge of Bovine Tuberculosis, Cattle Husbandry and Dairy Practices amongst Pastoralists and Small-Scale Dairy Farmers in Cameroon

Science.gov (United States)

Kelly, Robert F.; Hamman, Saidou M.; Morgan, Kenton L.; Nkongho, Egbe F.; Ngwa, Victor Ngu; Tanya, Vincent; Andu, Walters N.; Sander, Melissa; Ndip, Lucy; Handel, Ian G.; Mazeri, Stella; Muwonge, Adrian; Bronsvoort, Barend M. de. C.

2016-01-01

Background Control of bovine tuberculosis (bTB) and zoonotic tuberculosis (zTB) has relied upon surveillance and slaughter of infected cattle, milk pasteurisation and public health education. In Cameroon, like many other sub-Saharan African countries, there is limited understanding of current cattle husbandry or milk processing practices or livestock keepers awareness of bTB. This paper describes husbandry and milk processing practices within different Cameroonian cattle keeping communities and bTB awareness in comparison to other infectious diseases. Study design A population based cross-sectional sample of herdsmen and a questionnaire were used to gather data from pastoralists and dairy farmers in the North West Region and Vina Division of Cameroon. Results Pastoralists were predominately male Fulanis who had kept cattle for over a decade. Dairy farmers were non-Fulani and nearly half were female. Pastoralists went on transhumance with their cattle and came into contact with other herds and potential wildlife reservoirs of bTB. Dairy farmers housed their cattle and had little contact with other herds or wildlife. Pastoralists were aware of bTB and other infectious diseases such as foot-and-mouth disease and fasciolosis. These pastoralists were also able to identify clinical signs of these diseases. A similar proportion of dairy farmers were aware of bTB but fewer were aware of foot-and-mouth and fasciolosis. In general, dairy farmers were unable to identify any clinical signs for any of these diseases. Importantly most pastoralists and dairy farmers were unaware that bTB could be transmitted to people by consuming milk. Conclusions Current cattle husbandry practices make the control of bTB in cattle challenging especially in mobile pastoralist herds. Routine test and slaughter control in dairy herds would be tractable but would have profound impact on dairy farmer livelihoods. Prevention of transmission in milk offers the best approach for human risk mitigation

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...

Volcanic ash as fertiliser for the surface ocean

Directory of Open Access Journals (Sweden)

B. Langmann

2010-04-01

Full Text Available Iron is a key limiting micro-nutrient for marine primary productivity. It can be supplied to the ocean by atmospheric dust deposition. Volcanic ash deposition into the ocean represents another external and so far largely neglected source of iron. This study demonstrates strong evidence for natural fertilisation in the iron-limited oceanic area of the NE Pacific, induced by volcanic ash from the eruption of Kasatochi volcano in August 2008. Atmospheric and oceanic conditions were favourable to generate a massive phytoplankton bloom in the NE Pacific Ocean which for the first time strongly suggests a connection between oceanic iron-fertilisation and volcanic ash supply.

Understanding of research, genetics and genetic research in a rapid ethical assessment in north west Cameroon.

Science.gov (United States)

Kengne-Ouafo, Jonas A; Millard, James D; Nji, Theobald M; Tantoh, William F; Nyoh, Doris N; Tendongfor, Nicholas; Enyong, Peter A; Newport, Melanie J; Davey, Gail; Wanji, Samuel

2016-05-01

There is limited assessment of whether research participants in low-income settings are afforded a full understanding of the meaning of medical research. There may also be particular issues with the understanding of genetic research. We used a rapid ethical assessment methodology to explore perceptions surrounding the meaning of research, genetics and genetic research in north west Cameroon. Eleven focus group discussions (including 107 adults) and 72 in-depth interviews were conducted with various stakeholders in two health districts in north west Cameroon between February and April 2012. Most participants appreciated the role of research in generating knowledge and identified a difference between research and healthcare but gave varied explanations as to this difference. Most participants' understanding of genetics was limited to concepts of hereditary, with potential benefits limited to the level of the individual or family. Explanations based on supernatural beliefs were identified as a special issue but participants tended not to identify any other special risks with genetic research. We demonstrated a variable level of understanding of research, genetics and genetic research, with implications for those carrying out genetic research in this and other low resource settings. Our study highlights the utility of rapid ethical assessment prior to complex or sensitive research. © The Author 2015. Published by Oxford University Press on behalf of Royal Society of Tropical Medicine and Hygiene.

Delayed entry into HIV care after diagnosis in two specialized care and treatment centres in Cameroon: the influence of CD4 count and WHO staging

Directory of Open Access Journals (Sweden)

Noah F. Takah

2016-07-01

Full Text Available Abstract Background Delayed entry into HIV care has complicated the challenges faced in sub-Saharan Africa due to the high HIV burden. A clear knowledge of the factors affecting delayed entry will be essential in directing interventions towards reducing delayed entry into HIV care. There exist very limited data on delayed entry in Cameroon despite its relevance; hence this study was conducted to determine the rate of delayed entry and its associated factors in HIV programmes in Cameroon. Methods Data used for this study was routine data obtained from the files of HIV patients who were diagnosed between January 1, 2015 and June 30, 2015 at Limbe and Buea regional hospital HIV centers in the South West region of Cameroon. Data analysis was done using SPSS version 20. Results Of the 223 patients included in the study, nearly one-quarter of patients (22.4 % delayed to enter HIV care within 3 months. Those who delayed to enter care were less likely to present at first diagnosis (using HIV rapid test with symptoms such as fever > 1 month (5 % versus 30 %, p = 0.01 and weight loss > 10 % (13 % versus 48 %, p < 0.001. Alcohol consumption, WHO stage and CD4 count levels were also associated with delayed entry in bivariate analysis. In multivariate analysis only CD4 count greater than 500cells/μl and WHO stages I and II were independently associated with delayed entry into HIV care within 3 months. Conclusion In the South West region of Cameroon, approximately 1 out of 4 patients delay to enter HIV care. This high proportion of patients who delay to enter care correlates to the findings recorded by other studies in sub Saharan Africa. Interventions tackling delayed entry into HIV care might need to be favorably directed towards patients that have high CD4 counts and are at very early WHO clinical stages.

Geochemical evidence for waning magmatism and polycyclic volcanism at Crater Flat, Nevada

International Nuclear Information System (INIS)

Perry, F.V.; Crowe, B.M.

1992-01-01

This paper reports that petrologic and geochemical studies of basaltic rocks in the Yucca Mountain region are currently focused on understanding the evolution of volcanism in the Crater Flat volcanic field and the mechanisms of polycyclic volcanic field and the mechanisms of polycyclic volcanism at the Lathrop Wells volcanic center, the youngest center in the Crater Flat volcanic field. Geochemical and petrologic data indicate that the magma chambers which supplied the volcanic centers at Crater Flat became situated at greater crustal depths as the field evolved. Deep magma chambers may be related to a waning magma flux that was unable to sustain upper crustal magma conduits and chambers. Geochemical data from the Lathrop Wells volcanic center indicate that eruptive units identified from field and geomorphic relationships are geochemically distinct. The geochemical variations cannot be explained by fractional crystallization of a single magma batch, indicating that several magma batches were involved in the formation of the Lathrop Wells center. Considering the low magma flux in the Yucca Mountain region in the Quaternary, the probability of several magma batches erupting essentially simultaneously at Lathrop Wells is considered remote

What, When, Where, and Why of Secondary Hawaiian Hotspot Volcanism

Science.gov (United States)

Garcia, M. O.; Ito, G.; Applegate, B.; Weis, D.; Swinnard, L.; Flinders, A.; Hanano, D.; Nobre-Silva, I.; Bianco, T.; Naumann, T.; Geist, D.; Blay, C.; Sciaroni, L.; Maerschalk, C.; Harpp, K.; Christensen, B.

2007-12-01

Secondary hotspot volcanism occurs on most oceanic island groups (Hawaii, Canary, Society) but its origins remain enigmatic. A 28-day marine expedition used multibeam bathymetry and acoustic imagery to map the extent of submarine volcanic fields around the northern Hawaiian Islands (Kauai, Niihau and Kaula), and the JASON2 ROV to sample many volcanoes to characterize the petrology, geochemistry (major and trace elements, and isotopes) and ages of the lavas from these volcanoes. Our integrated geological, geochemical and geophysical study attempts to examine the what (compositions and source), where (distribution and volumes), when (ages), and why (mechanisms) of secondary volcanism on and around the northern Hawaiian Islands. A first-order objective was to establish how the submarine volcanism relates in space, time, volume, and composition to the nearby shield volcanoes and their associated onshore secondary volcanism. Our surveying and sampling revealed major fields of submarine volcanoes extending from the shallow slopes of these islands to more than 100 km offshore. These discoveries dramatically expand the volumetric importance, distribution and geodynamic framework for Hawaiian secondary volcanism. New maps and rock petrology on the samples collected will be used to evaluate currently proposed mechanisms for secondary volcanism and to consider new models such as small-scale mantle convection driven by thermal and melt-induced buoyancy to produce the huge volume of newly discovered lava. Our results seem to indicate substantial revisions are needed to our current perceptions of hotspot dynamics for Hawaii and possibly elsewhere.

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.

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

Directory of Open Access Journals (Sweden)

Catherine Lytrice AKAMBA MANI

2009-06-01

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

Volcanic unrest and hazard communication in Long Valley Volcanic Region, California

Science.gov (United States)

Hill, David P.; Mangan, Margaret T.; McNutt, Stephen R.

2017-01-01

The onset of volcanic unrest in Long Valley Caldera, California, in 1980 and the subsequent fluctuations in unrest levels through May 2016 illustrate: (1) the evolving relations between scientists monitoring the unrest and studying the underlying tectonic/magmatic processes and their implications for geologic hazards, and (2) the challenges in communicating the significance of the hazards to the public and civil authorities in a mountain resort setting. Circumstances special to this case include (1) the sensitivity of an isolated resort area to media hype of potential high-impact volcanic and earthquake hazards and its impact on potential recreational visitors and the local economy, (2) a small permanent population (~8000), which facilitates face-to-face communication between scientists monitoring the hazard, civil authorities, and the public, and (3) the relatively frequent turnover of people in positions of civil authority, which requires a continuing education effort on the nature of caldera unrest and related hazards. Because of delays associated with communication protocols between the State and Federal governments during the onset of unrest, local civil authorities and the public first learned that the U.S. Geological Survey was about to release a notice of potential volcanic hazards associated with earthquake activity and 25-cm uplift of the resurgent dome in the center of the caldera through an article in the Los Angeles Times published in May 1982. The immediate reaction was outrage and denial. Gradual acceptance that the hazard was real required over a decade of frequent meetings between scientists and civil authorities together with public presentations underscored by frequently felt earthquakes and the onset of magmatic CO2 emissions in 1990 following a 11-month long earthquake swarm beneath Mammoth Mountain on the southwest rim of the caldera. Four fatalities, one on 24 May 1998 and three on 6 April 2006, underscored the hazard posed by the CO2�

Magnetic properties of frictional volcanic materials

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Kendrick, Jackie E.; Lavallée, Yan; Biggin, Andrew; Ferk, Annika; Leonhardt, Roman

2015-04-01

During dome-building volcanic eruptions, highly viscous magma extends through the upper conduit in a solid-like state. The outer margins of the magma column accommodate the majority of the strain, while the bulk of the magma is able to extrude, largely undeformed, to produce magma spines. Spine extrusion is often characterised by the emission of repetitive seismicity, produced in the upper <1 km by magma failure and slip at the conduit margins. The rheology of the magma controls the depth at which fracture can occur, while the frictional properties of the magma are important in controlling subsequent marginal slip processes. Upon extrusion, spines are coated by a carapace of volcanic fault rocks which provide insights into the deeper conduit processes. Frictional samples from magma spines at Mount St. Helens (USA), Soufriere Hills (Montserrat) and Mount Unzen (Japan) have been examined using structural, thermal and magnetic analyses to reveal a history of comminution, frictional heating, melting and cooling to form volcanic pseudotachylyte. Pseudotachylyte has rarely been noted in volcanic materials, and the recent observation of its syn-eruptive formation in dome-building volcanoes was unprecedented. The uniquely high thermal conditions of volcanic environments means that frictional melt remains at elevated temperatures for longer than usual, causing slow crystallisation, preventing the development of some signature "quench" characteristics. As such, rock-magnetic tests have proven to be some of the most useful tools in distinguishing pseudotachylytes from their andesite/ dacite hosts. In volcanic pseudotachylyte the mass normalised natural remanent magnetisation (NRM) when further normalised with the concentration dependent saturation remanence (Mrs) was found to be higher than the host rock. Remanence carriers are defined as low coercive materials across all samples, and while the remanence of the host rock displays similarities to an anhysteretic remanent

SYSTHESIS OF VOLCANISM STUDIES FOR THE YUCCA MOUNTAIN SITE CHARACTERIZATION PROJECT

Energy Technology Data Exchange (ETDEWEB)

Perry, F. V.; Crowe, G. A.; Valentine, G. A.; Bowker, L. M.

1997-09-23

This report synthesizes the results of volcanism studies conducted by scientists at the Los Alamos National Laboratory and collaborating institutions on behalf of the Department of Energy's Yucca Mountain Project. Chapter 1 introduces the volcanism issue for the Yucca Mountain site and provides the reader with an overview of the organization, content, and significant conclusions of this report. The hazard of future basaltic volcanism is the primary topic of concern including both events that intersect a potential repository and events that occur near or within the waste isolation system of a repository. Future volcanic events cannot be predicted with certainty but instead are estimated using formal methods of probabilistic volcanic hazard assessment (PVHA). Chapter 2 describes the volcanic history of the Yucca Mountain region (YMR) and emphasizes the Pliocene and Quaternary volcanic record, the interval of primary concern for volcanic risk assessment. The distribution, eruptive history, and geochronology of Plio-Quaternary basalt centers are described by individual center emphasizing the younger postcaldera basalt (<5 Ma). The Lathrop Wells volcanic center is described in detail because it is the youngest basalt center in the YMR. The age of the Lathrop Wells center is now confidently determined to be about 75 thousand years old. Chapter 3 describes the tectonic setting of the YMR and presents and assesses the significance of multiple alternative tectonic models. The distribution of Pliocene and Quaternary basaltic volcanic centers is evaluated with respect to tectonic models for detachment, caldera, regional and local rifting, and the Walker Lane structural zone. Geophysical data are described for the YMR and are used as an aid to understand the distribution of past basaltic volcanic centers and possible future magmatic processes. Chapter 4 discusses the petrologic and geochemical features of basaltic volcanism in the YMR, the southern Great Basin and the

Petrogenesis of volcanic rocks that host the world-class Agsbnd Pb Navidad District, North Patagonian Massif: Comparison with the Jurassic Chon Aike Volcanic Province of Patagonia, Argentina

Science.gov (United States)

Bouhier, Verónica E.; Franchini, Marta B.; Caffe, Pablo J.; Maydagán, Laura; Rapela, Carlos W.; Paolini, Marcelo

2017-05-01

We present the first study of the volcanic rocks of the Cañadón Asfalto Formation that host the Navidad world-class Ag + Pb epithermal district located in the North Patagonian Massif, Patagonia, Argentina. These volcanic and sedimentary rocks were deposited in a lacustrine environment during an extensional tectonic regime associated with the breakup of Gondwana and represent the mafic to intermediate counterparts of the mainly silicic Jurassic Chon Aike Volcanic Province. Lava flows surrounded by autobrecciated carapace were extruded in subaerial conditions, whereas hyaloclastite and peperite facies suggest contemporaneous subaqueous volcanism and sedimentation. LA-ICPMS Usbnd Pb ages of zircon crystals from the volcanic units yielded Middle Jurassic ages of 173.9 ± 1.9 Ma and 170.8 ± 3 Ma. In the Navidad district, volcanic rocks of the Cañadón Asfalto Formation show arc-like signatures including high-K basaltic-andesite to high-K dacite compositions, Rb, Ba and Th enrichment relative to the less mobile HFS elements (Nb, Ta), enrichment in light rare earth elements (LREE), Ysbnd Ti depletion, and high Zr contents. These characteristics could be explained by assimilation of crustal rocks in the Jurassic magmas, which is also supported by the presence of zircon xenocrysts with Permian and Middle-Upper Triassic ages (281.3 Ma, 246.5, 218.1, and 201.3 Ma) and quartz xenocrysts recognized in these volcanic units. Furthermore, Sr and Nd isotope compositions suggest a contribution of crustal components in these Middle Jurassic magmas. High-K basaltic andesite has initial 87Sr/86Sr ratios of 0.70416-0.70658 and ξNd(t) values of -5.3 and -4. High-K dacite and andesite have initial 87Sr/86Sr compositions of 0.70584-0.70601 and ξNd(t) values of -4,1 and -3,2. The range of Pb isotope values (206Pb/204Pb = 18.28-18.37, 207Pb/204Pb = 15.61-15.62, and 208Pb/204Pb = 38.26-38.43) of Navidad volcanic rocks and ore minerals suggest mixing Pb sources with contributions of