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Sample records for nucleaire au senegal

  1. Senegal.

    PubMed

    1991-07-01

    Background notes and statistics on Senegal are provided in the document. 196,840 sq. km. of diversified terrain are encompassed by the country, with a 1990 population of 7 million growing at the annual rate of 3%. The work force totals 3 million. Senegal claims a population comprised of 5 ethnic groups and various others, 3 religious beliefs, and speaking 5 languages. No period of education is listed as compulsory, with the country overall experiencing 28% literacy. The infant mortality rate is 78/1,000, while life expectancy is 48 years. 1989 GDP was $5 billion, and was growing at the rate of 6%. 1988 per capita GDP was $630, with a 1989 inflation rate of 2%. Agriculture accounts for 22% of GDP, industry for 24%; 1990 international trade deficit totalled $209 million. Additional data are provided on Senegal's people, government, economy, international affiliations, defense, history, political conditions, principal government officials, foreign relations, and bilateral relations with the United States. Senegal suffers from a resource-poor economy vulnerable to environmental and international commodity price fluctuations. The country depends heavily on international donor assistance. 70% of the labor force is engaged in farming, with peanuts accounting for 1/2 of agricultural output. Agroindustry investment is planned to bring Senegal further along toward food self-sufficiency. Fishing, phosphate production, and tourism are all areas for economic growth. Economic reforms along with favorable weather in recent years have resulted in real GDP growth. Foreign investment is welcomed in Senegal, as demonstrated by revised terms set forth in the investment code of 1987. PMID:12178030

  2. Une Nouvelle Place pour le francais au Senegal? (A New Place for French in Senegal?)

    ERIC Educational Resources Information Center

    Ka, Omar

    1993-01-01

    A discussion of the role of the French language in Senegal first chronicles language and education policy from the colonial period until 1980, then cites research indicating that French is infrequently used for personal purposes. Recent initiatives to strengthen its status and usage, and obstacles to their success, are outlined. (MSE)

  3. Teaching English in Francophone Senegal.

    ERIC Educational Resources Information Center

    Davis, Kay

    2002-01-01

    Examines the English teaching situation in the African Francophone country of Senegal. Discusses education in general in Senegal, English clubs, English teacher preparation, exchange and study abroad programs, and professional activities and organizations. (Author/VWL)

  4. Changing School Science in Senegal

    ERIC Educational Resources Information Center

    Peacock, Alan

    2003-01-01

    The Republic of Senegal, formerly a French colony, is the westernmost country in Africa. It is a three-party democracy, with 92% of the population being Muslim. The structure of education is still closely modelled on the French system of "Elementaire" (Basic) from 7 to 13, "Moyen" (Middle) from 13 to 16 and "Secondaire" (Upper Secondary) from 17…

  5. Rights of the Child in Senegal.

    ERIC Educational Resources Information Center

    Lacroix, Anne-Laurence; Mejia, Fernando

    This report to the United Nations Committee on the Rights of the Child contains observations of the World Organisation Against Torture (OMCT) concerning the application of the U.N. Convention on the Rights of the Child by the Republic of Senegal. Part 1 of the report, "Preliminary Observations," discusses Senegal's ratification of the Convention…

  6. Area Handbook for Senegal. Second Edition.

    ERIC Educational Resources Information Center

    Nelson, Harold D.; And Others

    This volume on Senegal is one of a series of handbooks prepared by Foreign Area Studies (FAS) of the American University. It is designed to be useful to military and other personnel who need a convenient compilation of basic facts about the social, economic, political, and military institutions and practices of Senegal. The emphasis is on…

  7. Ecoregions and land cover trends in Senegal

    USGS Publications Warehouse

    Tappan, G. Gray; Sall, M.; Wood, E.C.; Cushing, M.

    2004-01-01

    This study examines long-term changes in Senegal's natural resources. We monitor and quantify land use and land cover changes occurring across Senegal using nearly 40 years of satellite imagery, aerial surveys, and fieldwork. We stratify Senegal into ecological regions and present land use and land cover trends for each region, followed by a national summary. Results aggregated to the national level show moderate change, with a modest decrease in savannas from 74 to 70 percent from 1965 to 2000, and an expansion of cropland from 17 to 21 percent. However, at the ecoregion scale, we observed rapid change in some and relative stability in others. One particular concern is the decline in Senegal's biodiverse forests. However, in the year 2000, Senegal's savannas, woodlands, and forests still cover more than two-thirds of the country, and the rate of agricultural expansion has slowed.

  8. Senegal: The Battle to Create Employment

    ERIC Educational Resources Information Center

    Diop, Papa Amet

    1970-01-01

    Senegal suffers from an exodus from rural to urban areas and severe unemployment and underemployment. Efforts are made to adapt manpower training programs to economic reality. Programs include electrical engineering, rural nursing, handicrafts, and midwifery. (NL)

  9. Republic of Senegal. Country profile.

    PubMed

    Gold, D

    1985-04-01

    The demographic and economic characteristics and some of the cultural traditions of the Republic of Senegal are described. Senegal obtained its independence from France in 1960. Despite the fact that the majority of the population derives its living from agriculture, the country must import additional food staples to feed its population. Conditions contributing to poor crop yields in recent years include 1) the frequent occurrence of droughts, 2) soil depletion caused by overintensive cultivation practices, and 3) land dessication caused by poor forestry management. In 1984 crop yields were only 10% of the normal crop yields. The government under the leadership of the president, Adbou Diouf, is currently developing plans to improve agricultural conditions and to encourage the industrial development of the country. The tourist industry is also growing. In 1976 Senegal conducted it 1st national census. According to the census the total population was 5,068,741 and the population growth rate was 2.6%. The US Census Bureau estimates that the population growth rate is now 3.2% and that 654,000 people were added to the population between 1976 and 1985. 27% of the population is urban, and the majority of the urban population resides in Dakar. In recent years, the rate of rural to urban migration increased rapidly as a result of the deteriorating agricultural conditions. The population is unevenly distributed throughout the country; 82% of the population lives in 39% of the country's territory. In 1977, 18% of the population lived in housing with electricity, and in 1983, 37% of the population lived in housing with running water. Most rural residents live in villages consisting of clusters of clay structures with thatched roofs and dirt floors. Most of the urban poor live in crowded shantytowns, which lack urban services. More than 1/2 of the population is under the age of 18. According to the 1978 World Fertility Survey, 83% of all women of reproductive age are married

  10. Partnerships in the Education System of Senegal

    ERIC Educational Resources Information Center

    Ndiaye, Malick

    2006-01-01

    After gaining independence, at the Addis Ababa meeting (1961) most African countries, including Senegal, decided to develop their education systems. In 1980, a number of objectives were set out, including the democratization of primary education and universal sustainable schooling. According to its economic possibilities, its human resources and…

  11. Risk analysis. HIV / AIDS country profile: Senegal.

    PubMed

    1996-12-01

    Since the first acquired immunodeficiency syndrome (AIDS) case was confirmed in 1986, Senegal has conducted an aggressive prevention campaign. Senegal's National AIDS Committee has noted the contributions of poverty and migration to the spread of AIDS. By June 1994, 1297 AIDS cases had been reported and an estimated 500,000 people (1.4% of the population) were infected with human immunodeficiency virus (HIV)-1 and 2. The highest rate of HIV infection (14%) exists among commercial sex workers. At present, HIV/AIDS cases are concentrated in Dakar, Kaolack, the Matam region, and Ziguinchor; however, the growing importance of inter-regional trading is expected to spread HIV to the smaller towns and rural areas. Also salient is the recent devaluation by 50% of the CFA franc, which has reduced the public sector workforce and led many poor urban residents into commercial sex work. CFA devaluation has made Senegal attractive to tourists and business visitors--another factor responsible for growth of the legalized commercial sex industry. Although sex workers are instructed in condom use and tested annually for HIV, only 850 of the 2000 registered sex workers have reported for check-ups, and the majority of prostitutes are unregistered. Senegal's AIDS Plan for 1994-98 focuses on care of AIDS patients, pressures placed on family structures by HIV, and AIDS-related erosions in the status of women. Each health service region has its own local plan for AIDS/HIV and sexually transmitted diseases, supervised by a regional committee. Public education has involved outreach to religious leaders, promotion of affordable condoms, and distribution of over 75,000 leaflets to key target populations. About US $16 million of the $25,688,875-budget HIV/AIDS program for 1994-98 was pledged by external donors. PMID:12320531

  12. [Serological survey of animal toxoplasmosis in Senegal].

    PubMed

    Davoust, B; Mediannikov, O; Roqueplo, C; Perret, C; Demoncheaux, J-P; Sambou, M; Guillot, J; Blaga, R

    2015-02-01

    Toxoplasma gondii is an obligate, intracellular, parasitic protozoan within the phylum Apicomplexa that causes toxoplasmosis in mammalian hosts (including humans) and birds. We used modified direct agglutination test for the screening of the animals' sera collected in Senegal. In total, 419 animals' sera have been studied: 103 bovines, 43 sheep, 52 goats, 63 horses, 13 donkeys and 145 dogs. The collection of sera was performed in four different regions of Senegal: Dakar, Sine Saloum, Kedougou and Basse Casamance from 2011 to 2013. We have revealed antibodies in 13% of bovines, 16% of sheep, 15% of goats, 30% of horses, 23% of donkeys and 67% of dogs. Private dogs from villages were more often to have the anti-Toxoplasma antibodies compared to security society-owned dogs from Dakar. It may be explained by different meal consumed by dogs (factory-produced meal for dogs from Dakar vs. irregular sources for village dogs). Intense circulation of T. gondii in the studied zone may explain the unusually high seroprevalence among horses and donkeys. Tropical climate with high temperature and humidity is favorable for the conservation of oocysts of T. gondii. Results presented here may contribute to the evaluation of the risks of toxoplasmosis in humans in Senegal. PMID:25307881

  13. International Interdisciplinary Research Institute Project in Senegal

    NASA Astrophysics Data System (ADS)

    Gueye, Paul

    2010-02-01

    The project of an interdisciplinary research institute in Senegal was initiated in 1993 in Senegal (West Africa) and became a template for a similar project in the US in 1999. Since then, numerous meetings and presentations have been held at various national and international institutions, workshops and conferences. The current development of this partnership includes drafts for a full design of all systems at each facility, as well as the physics, applied health and educational programs to be implemented. The Senegal facility was conceived for scientific capacity building and equally to act as a focal point aimed at using the local scientific expertise. An anticipated outcome would be a contribution to the reduction of an ever-growing brain drain process suffered by the country, and the African continent in general. The development of the project led also to a strong African orientation of the facility: built for international collaboration, it is to be a pan-African endeavor and to serve primarily African countries. The facility received a presidential approval in a 2003 meeting and will develop an interdisciplinary program centered on a strong materials science research which will also allow for the establishment of an advanced analytical (physical chemistry) laboratory. A central part of the facility will be linked to state-of-the art accelerator mass spectrometry, cyclotron and low energy electromagnetic accelerator systems. )

  14. Job Satisfaction in the Coastal Pelagic Fisheries of Senegal

    ERIC Educational Resources Information Center

    Sall, Aliou

    2012-01-01

    The marine fishery in Senegal, West Africa, is a major source of employment and food security. It currently faces the consequences of ecological degradation. This paper examines job satisfaction among small-scale purse seine fishers, who constitute one of the dominant fishing metiers in Senegal. The research sample consists of 80 purse seine…

  15. [Long term adherence to HAART in Senegal].

    PubMed

    Bastard, M; Fall, M Basty Koita

    2014-10-01

    Adherence is one of the main predictors of antiretroviral treatment success. A governmental initiative was launched in 1998 for HIV-infected patients in Senegal to provide access to highly active antiretroviral therapy (HAART). Adherence measurements, defined as pills taken/pills prescribed, were assessed between November 1999 and June 2010 using a pill count along with a questionnaire for 330 patients. Predictors of adherence and identification of adherence trajectories were explored through latent class mixed model. We also performed a survival analysis using Cox proportional hazard model. Three adherence behaviours were revealed as well as a better adherence for women. A third of patients had a high adherence trajectory over time and a third had an intermediate one. Male gender and low adherence behaviour over time were independently associated with a higher mortality rate. This study shows that an overall good adherence can be obtained in the long term in Senegal, suggests a better adherence for women and points out a large subsample of patients with intermediate level of adherence behaviour who are at risk for developing resistance to antiretroviral drugs. PMID:24615434

  16. Physics in Africa: The Case of Senegal

    NASA Astrophysics Data System (ADS)

    Arame Boye-Faye, Ndeye

    2009-03-01

    For many years, the research activity in Senegal has been managed through the division of the Ministry of Education. In 2004 the current government established a full-fledged Ministry of Research. This has led to a renewed focus on the organization of the funding of research in Senegal. One important issue to underline is the lack of a budget line devoted to research in most of the local institutions, distinct from support for academic purposes. As a result, the research activity is funded through direct support from the government or thanks to international programs. The main tool for the government to support key research directions is the FIRST program, with a yearly budget of 700,000 US. For the last call for projects, up to 12 projects have been funded, which translates to about 58,000 US per project. The other option for research funding lies in different international programs specifically aimed at institutions within the least developed countries. The dominant ones are provided by the French-speaking community, the French-supported AIRE, the European Union framework and ICTP Abdus Salam Centre. In this general context of limited resources, physics is the least supported discipline both in terms of researchers and active laboratories. As a result, particular efforts have to be made to increase the impact of physics and the role of physicists so as to enable them to claim their proper role as the major player in making science and technology the driving forces in the development process of Africa.

  17. [Comparative analysis of adolescent fertility in Senegal and Mali].

    PubMed

    Traore, B

    1990-08-01

    A demographer has analyzed data on women aged 15-19 from the Demographic and Health Surveys of Mali and of Senegal to compare their adolescent fertility rates and the determinants of adolescent fertility. 50% of married women in Mali were first married at 15.7 years compared to 16.6 years in Senegal. 30% of teens were married before age 14 in Mali compared to 14% in Senegal. In fact, single women were two times more common in Senegal than in Mali (56.5% vs. 24.6%). 71.5% of teens in Mali were married compared to 41.9% in Senegal. 28% of female teens lived in urban areas in Mali compared to 44.8% in Senegal. In Mali, the marriage law states that men must be at least 18 and women must be at least 15. Reasons women marry before age 15 include marriage based on degree of physical development rather than age, unofficial weddings, and misrepresentation of age. Thus, it is not unusual to meet married women aged 13, 14, and 15 in rural areas. In Senegal, however, the minimum marriage age was 20 for men and 16 for women. Despite the differences, among married women, pregnant adolescents comprised the same proportion (16.5% in Mali and 16.9% in Senegal). Yet, 44.5% of female teens in Mali have a child compared to 26.1% in Senegal. Fecund teens comprised 59.4% in Mali and 54.5% in Senegal. Even though teens in Mali were less likely to know about contraception (41.3% vs. 74.6%), they were more likely to use it (16.1% vs. 11.5%). They may have been using it to space their second birth. Between 1957-1961 and 1967-1971, adolescent fertility remained constant, while it increased during the 1970s. It fell during 1982-1986. In Senegal, between 1956-1960 and 1961-1965, adolescent fertility increased, while it remained constant between 1961-1965 and 1976-1980. During 1981-1985, it decreased markedly. The decrease in adolescent fertility in the 1980s paralleled an increase in female education. PMID:12346455

  18. A climate trend analysis of Senegal

    USGS Publications Warehouse

    Funk, Christopher C.; Rowland, Jim; Adoum, Alkhalil; Eilerts, Gary; Verdin, James; White, Libby

    2012-01-01

    This brief report, drawing from a multi-year effort by the U.S. Agency for International Development (USAID) Famine Early Warning Systems Network (FEWS NET), identifies modest declines in rainfall, accompanied by increases in air temperatures. These analyses are based on quality-controlled station observations. Conclusions: * Summer rains have remained steady in Senegal over the past 20 years but are 15 percent below the 1920-1969 average. * Temperatures have increased by 0.9° Celsius since 1975, amplifying the effect of droughts. * Cereal yields are low but have been improving. * The amount of farmland per person is low and declining rapidly. * Current population and agriculture trends could lead to a 30-percent reduction in per capita cereal production by 2025.

  19. Female Employment Reduces Fertility in Rural Senegal

    PubMed Central

    2015-01-01

    Economic growth and modernization of society are generally associated with fertility rate decreases but which forces trigger this is unclear. In this paper we assess how fertility changes with increased labor market participation of women in rural Senegal. Evidence from high-income countries suggests that higher female employment rates lead to reduced fertility rates but evidence from developing countries at an early stage of demographic transition is largely absent. We concentrate on a rural area in northern Senegal where a recent boom in horticultural exports has been associated with a sudden increase in female off-farm employment. Using survey data we show that employed women have a significantly higher age at marriage and at first childbirth, and significantly fewer children. As causal identification strategy we use instrumental variable and difference-in-differences estimations, combined with propensity score matching. We find that female employment reduces the number of children per woman by 25%, and that this fertility-reducing effect is as large for poor as for non-poor women and larger for illiterate than for literate women. Results imply that female employment is a strong instrument for empowering rural women, reducing fertility rates and accelerating the demographic transition in poor countries. The effectiveness of family planning programs can increase if targeted to areas where female employment is increasing or to female employees directly because of a higher likelihood to reach women with low-fertility preferences. Our results show that changes in fertility preferences not necessarily result from a cultural evolution but can also be driven by sudden and individual changes in economic opportunities. PMID:25816301

  20. High Prevalence of Mansonella perstans Filariasis in Rural Senegal

    PubMed Central

    Bassene, Hubert; Sambou, Masse; Fenollar, Florence; Clarke, Siân; Djiba, Sawdiatou; Mourembou, Gaël; L. Y., Alioune Badara; Raoult, Didier; Mediannikov, Oleg

    2015-01-01

    Large parts of African and American countries are colonized by Mansonella, a very common but poorly described filarial nematode. Bloodsucking flies of the genus Culicoides are suspected to be the vector of Mansonella perstans, but no study in Senegal has confirmed that Culicoides can transmit the parasite. Designed specific real-time quantitative polymerase chain reaction (qPCR) can be used to identify microfilaria in stained blood smears. This study was performed in July and December 2010 in the southeastern Senegal, which is known to be endemic for M. perstans. We analyzed 297 blood smears from febrile and afebrile resident people by qPCR. The global prevalence of M. perstans was approximately 14.5% in both febrile and afebrile individuals. The age group of > 30 years had the highest prevalence (22.0%). No Culicoides among 1,159 studied specimens was positive for M. perstans and its vector in Senegal still requires identification. PMID:26078318

  1. Assessing the basement aquifers of Eastern Senegal

    NASA Astrophysics Data System (ADS)

    Diop, S.; Tijani, M. N.

    2008-11-01

    An analysis is presented of the chemical and isotopic measurements on groundwater samples from the basement aquifers of Eastern Senegal, in an attempt to shed light on the current hydrogeological conditions. The results demonstrate the use of isotopes together with conventional major ion chemistry as a convenient tool in hydrogeology. The discussion focuses on a description of the study area, with attention to pertinent details; a model of hydrochemical evolution, developed for the apparent bipolarity of the water facies; and a conception of groundwater storage dynamics and basin characteristics regarding geology (notably, identification of the main recharge mechanisms and locations). The main indications are that calcium-bicarbonate dominated “recent” groundwater evolves during confinement into sodium-bicarbonate dominated groundwater through calcium-for-sodium cation exchange. The drainage, fault and fracture systems provide movement for groundwater recharge. Moreover, the tritium distribution provides evidence to support the hypothesis of piston flow, consistent with the manner in which wells have been designed with reference to aquifer configuration. Estimates of recharge, as determined from the tritium data, are approximately 15%. There was a very good match between results obtained from two different approaches.

  2. Land use change and terrestrial carbon stocks in Senegal

    USGS Publications Warehouse

    Woomer, P.L.; Tieszen, L.L.; Tappan, G.; Toure, A.; Sall, M.

    2004-01-01

    Environmental degradation resulting from long-term drought and land use change has affected terrestrial carbon (C) stocks within Africa's Sahel. We estimated Senegal's terrestrial carbon stocks in 1965, 1985, and 2000 using an inventory procedure involving satellite images revealing historical land use change, and recent field measurements of standing carbon stocks occurring in soil and plants. Senegal was divided into eight ecological zones containing 11 land uses. In 2000, savannas, cultivated lands, forests, and steppes were the four largest land uses in Senegal, occupying 70, 22, 2.7, and 2.3 percent of Senegal's 199,823km2. System C stocks ranged from 9tCha-1 in degraded savannas in the north, to 113tCha-1 in the remnant forests of the Senegal River Valley. This approach resulted in estimated total C stocks of 1019 and 727MTC between 1965 and 2000, respectively, indicating a loss of 292MTC over 35 years. The proportion of C residing in biomass decreased with time, from 55 percent in 1965 to 38 percent in 2000. Calculated terrestrial C flux for 1993 was -7.5MTCyear-1 and had declined by 17 percent over the previous 18 years. Most of the terrestrial C flux in 1993 was attributed to biomass C reduction. Human disturbance accounted for only 22 percent of biomass C loss in 1993, suggesting that the effects of long-term Sahelian drought continue to play an overriding role in ecosystem change. Some carbon mitigation strategies for Senegal were investigated, including potential C sequestration levels. Opportunities for C mitigation exist but are constrained by available knowledge and access to resources. ?? 2004 Elsevier Ltd. All rights reserved.

  3. The Dynamics of Multilingualism: The Case of Senegal.

    ERIC Educational Resources Information Center

    Mansour, Gerda

    1980-01-01

    Describes a study which attempts to link micro and macro approaches in the study of societal multilingualism while introducing a diachronic perspective. The sociolinguistic profile of Senegal is used as a point of departure followed by an outline of sociohistorical factors which contributed to language use. Discusses the social implications of…

  4. Linguistic Resistance in the Murid Speech Community in Senegal.

    ERIC Educational Resources Information Center

    Ngom, Fallou

    2002-01-01

    Examines the religious and linguistic behavior of the Murid brotherhood in Touba, Senegal. Argues that the patterns of behavior found in the community are idiosyncratic of the brotherhood and set apart Murids from other religious groups. Argues that unlike other forms of resistance against French assimilation movements, Muridism represents one of…

  5. Polyadic Language Socialization Strategy: The Case of Toddlers in Senegal.

    ERIC Educational Resources Information Center

    Rabain-Jamin, Jacqueline

    1998-01-01

    Contributes to research on child-directed speech by examining the use of two types of utterances (reported speech and prompts) in interactions involving mothers, toddlers, and other adults or siblings in rural Senegal. Shows that mothers attempt to promote exchange in a triadic framework, with the goal of making the child part of a complex set of…

  6. Urban epidemic of dengue virus serotype 3 infection, Senegal, 2009.

    PubMed

    Faye, Ousmane; Ba, Yamar; Faye, Oumar; Talla, Cheikh; Diallo, Diawo; Chen, Rubing; Mondo, Mireille; Ba, Rouguiétou; Macondo, Edgard; Siby, Tidiane; Weaver, Scott C; Diallo, Mawlouth; Sall, Amadou Alpha

    2014-03-01

    An urban epidemic of dengue in Senegal during 2009 affected 196 persons and included 5 cases of dengue hemorrhagic fever and 1 fatal case of dengue shock syndrome. Dengue virus serotype 3 was identified from all patients, and Aedes aegypti mosquitoes were identified as the primary vector of the virus. PMID:24572297

  7. Urban Senegal and Rural Gambia: Computer and Community Education Programs.

    ERIC Educational Resources Information Center

    Pagano, Alicia I.

    1986-01-01

    Describes two educational programs in West Africa: a (LOGO) computer education program in Senegal, and a "self-improvement" community education program in The Gambia. While these two programs are diverse in geographic location, population, and curriculum materials, both are action-oriented, learner controlled, and consider the learner's broader…

  8. Energy and environment: A political ecology of woodfuels in Senegal

    NASA Astrophysics Data System (ADS)

    Pires, E. Mark

    This study examines relationships between energy use and the exploitation of woodland natural resources in the West African nation of Senegal. As in many other countries in the developing world, the majority of the population in Senegal depend on woodfuels, i.e., firewood and charcoal, to satisfy most of their household energy needs. Consequences of this situation include added pressure on the country's limited natural resource base, and increased socioeconomic hardship, particularly for women, as woodfuel resources become increasingly scarce. Woodfuel energy problems in developing countries are typically described in terms of an imbalance between supply and demand that is driven by rapid population growth. However, recent research suggests that a number of other factors should be explored in order to achieve a more thorough understanding of the relationship between woodfuel energy and forest resource management. This study attempts to determine what some of these factors are, and to explain how they inform the energy-environment situation in the case of Senegal. In addition, I examine the scope for addressing Senegal's woodfuel problem through greater local community participation in managing energy and natural resources, a current thrust in many international initiatives designed to help the country cope with this persistent problem. A relatively new conceptual framework for the analysis of human-environment relationships---viz. political ecology---is employed in this study. I attempt to show how political ecology can contribute to the resolution of Senegal's energy-environment dilemma by considering a more inclusive suite of social, economic, political, and environmental variables than has been explored by previous approaches. Findings from the research demonstrate the ability of the political ecology approach to capture many heretofore unexplored factors related to the energy-environment nexus in Senegal. A detailed matrix is generated that illustrates the

  9. Assessment of water availability and demand in Lake Guiers , Senegal.

    NASA Astrophysics Data System (ADS)

    Sambou, D.; Weihrauch, D.; Hellwing, V.; Diekkrüger, B.; Höllermann, B.; Gaye, A. T.

    2015-12-01

    Assessment of water availability and demand in Lake Guiers, SenegalWater resources are critical to economic growth and social development. In most African countries, supply of drinking water to satisfy population needs is a key issue because of population growth and climate and land use change. During the last three decades, increasing population, changing patterns of water demand, and concentration of population and economic activities in urban areas has pressurize Senegal's freshwater resources. To overcome this deficit, Senegal turned, to the exploitation of the Lake Guiers. It is the sole water reservoir which can be used extensively as a stable freshwater. Its water is use for irrigating crops and sugar refinery and as a drinking water resource for urban centres, including Dakar, the capital city of Senegal, as well as for the local population and animal herds. To ensure sustainability, a greater understanding of Lake Guiers's water resources and effective management of its use will be required. In this study we developed and quantified future water situation (water availability and demand) in Lake Guiers under scenarios of climate change and population growth until 2050, using the water management model WEAP (Water Evaluation And Planning system). The results show that the pressure on Lake Guiers's water resources will increase, leading to greater competition between agriculture and municipal demand site. Decreasing inflows due to climate change will aggravate this situation. WEAP results offer basis to assister lake Guiers water resources manager for an efficient long-term planning and management. Keywords: climate change, population growth , IWRM, Lake Guiers, Senegal

  10. Morocco and Senegal: Faces of Islam in Africa. Fulbright-Hays Summer Seminars Abroad, 1999 (Morocco and Senegal).

    ERIC Educational Resources Information Center

    Center for International Education (ED), Washington, DC.

    These projects were completed by participants in the Fulbright-Hays summer seminar in Morocco and Senegal in 1999. The participants represented various regions of the United States and different grade levels and subject areas. The 13 curriculum projects in the collection are: (1) "Doorway to Morocco: A Student Guide" (Sue Robertson); (2) "A Social…

  11. Greenwich turbine supplies Senegal with 25 MW in six months

    SciTech Connect

    1995-05-01

    Greenwich Turbine, Inc. (GTi) of East Granby, CT is a specialist firm in gas turbine repair/overhaul which has, in recent years, expanded into supplying gas turbine power plants in the 20- to 90-MW range. The sixteenth and latest power project was their most ambitious, a turbine plant for the West African nation of Senegal. The engine is a Pratt & Whitney FT4C-3F gas generator and power turbine. The plant was completed and commissioned on January 27, 1995, with the presidents of Senegal and Ivory Coast in attendance. The equipment is now going through a shake-down period, providing intermediate-duty power. And the GTi staff is justifiably proud of how quickly they were able to get this power online. 2 figs.

  12. [Anopheles of Senegal. An annotated and illustrated list].

    PubMed

    Diagne, N; Fontenille, D; Konate, L; Faye, O; Lamizana, M T; Legros, F; Molez, J F; Trape, J F

    1994-01-01

    Twenty species of Anopheles are presently known from Senegal. An. gambiae, An. arabiensis, An. pharoensis, An. rufipes and An. ziemanni have an extensive distribution. Probably because of climatic change, An. funestus is no more found in some areas and An. paludis tend to disappear. An. melas is located in coastal areas. The other species, namely An. coustani, An. brohieri, An. brunnipes, An. domicola, An. flavicosta, An. freetownensis, An. hancocki, An. maculipalpis, An. nili, An. pretoriensis, An. squamosus and An. wellcomei, are mainly found in southern Senegal. Only An. gambiae, An. arabiensis and An. funestus are of epidemiological significance as vectors of malaria and bancroftian filariasis. Twelve arboviruses have been isolated from eight Anopheles species. Each Anopheles species is illustrated and an identification key is given. PMID:7866049

  13. A National Medical Information System for Senegal: Architecture and Services.

    PubMed

    Camara, Gaoussou; Diallo, Al Hassim; Lo, Moussa; Tendeng, Jacques-Noël; Lo, Seynabou

    2016-01-01

    In Senegal, great amounts of data are daily generated by medical activities such as consultation, hospitalization, blood test, x-ray, birth, death, etc. These data are still recorded in register, printed images, audios and movies which are manually processed. However, some medical organizations have their own software for non-standardized patient record management, appointment, wages, etc. without any possibility of sharing these data or communicating with other medical structures. This leads to lots of limitations in reusing or sharing these data because of their possible structural and semantic heterogeneity. To overcome these problems we have proposed a National Medical Information System for Senegal (SIMENS). As an integrated platform, SIMENS provides an EHR system that supports healthcare activities, a mobile version and a web portal. The SIMENS architecture proposes also a data and application integration services for supporting interoperability and decision making. PMID:27577338

  14. Seroprevalence of African Swine Fever in Senegal, 2006

    PubMed Central

    Seck, Ismaila; Grosbois, Vladimir; Jori, Ferran; Blanco, Esther; Vial, Laurence; Akakpo, Ayayi J.; Bada-Alhambedji, Rianatou; Kone, Philippe; Roger, Francois L.

    2011-01-01

    In Senegal, during 2002–2007, 11 outbreaks of African swine fever (ASF) were reported to the World Organisation for Animal Health. Despite this, little was known of the epidemiology of ASF in the country. To determine the prevalence of ASF in Senegal in 2006, we tested serum specimens collected from a sample of pigs in the 3 main pig-farming regions for antibodies to ASF virus using an ELISA. Of 747 serum samples examined, 126 were positive for ASF, suggesting a prevalence of 16.9%. The estimated prevalences within each of the regions (Fatick, Kolda, and Ziguinchor) were 13.3%, 7.8%, and 22.1%, respectively, with statistical evidence to suggest that the prevalence in Ziguinchor was higher than in Fatick or Kolda. This regional difference is considered in relation to different farming systems and illegal trade with neighboring countries where the infection is endemic. PMID:21192854

  15. Agricultural activity shapes the communication and migration patterns in Senegal.

    PubMed

    Martin-Gutierrez, S; Borondo, J; Morales, A J; Losada, J C; Tarquis, A M; Benito, R M

    2016-06-01

    The communication and migration patterns of a country are shaped by its socioeconomic processes. The economy of Senegal is predominantly rural, as agriculture employs over 70% of the labor force. In this paper, we use mobile phone records to explore the impact of agricultural activity on the communication and mobility patterns of the inhabitants of Senegal. We find two peaks of phone calls activity emerging during the growing season. Moreover, during the harvest period, we detect an increase in the migration flows throughout the country. However, religious holidays also shape the mobility patterns of the Senegalese people. Hence, in the light of our results, agricultural activity and religious holidays are the primary drivers of mobility inside the country. PMID:27368795

  16. Agricultural activity shapes the communication and migration patterns in Senegal

    NASA Astrophysics Data System (ADS)

    Martin-Gutierrez, S.; Borondo, J.; Morales, A. J.; Losada, J. C.; Tarquis, A. M.; Benito, R. M.

    2016-06-01

    The communication and migration patterns of a country are shaped by its socioeconomic processes. The economy of Senegal is predominantly rural, as agriculture employs over 70% of the labor force. In this paper, we use mobile phone records to explore the impact of agricultural activity on the communication and mobility patterns of the inhabitants of Senegal. We find two peaks of phone calls activity emerging during the growing season. Moreover, during the harvest period, we detect an increase in the migration flows throughout the country. However, religious holidays also shape the mobility patterns of the Senegalese people. Hence, in the light of our results, agricultural activity and religious holidays are the primary drivers of mobility inside the country.

  17. Cholera outbreak in Senegal in 2005: was climate a factor?

    PubMed

    de Magny, Guillaume Constantin; Thiaw, Wassila; Kumar, Vadlamani; Manga, Noël M; Diop, Bernard M; Gueye, Lamine; Kamara, Mamina; Roche, Benjamin; Murtugudde, Raghu; Colwell, Rita R

    2012-01-01

    Cholera is an acute diarrheal illness caused by Vibrio cholerae and occurs as widespread epidemics in Africa. In 2005, there were 31,719 cholera cases, with 458 deaths in the Republic of Senegal. We retrospectively investigated the climate origin of the devastating floods in mid-August 2005, in the Dakar Region of Senegal and the subsequent outbreak of cholera along with the pattern of cholera outbreaks in three other regions of that country. We compared rainfall patterns between 2002 and 2005 and the relationship between the sea surface temperature (SST) gradient in the tropical Atlantic Ocean and precipitation over Senegal for 2005. Results showed a specific pattern of rainfall throughout the Dakar region during August, 2005, and the associated rainfall anomaly coincided with an exacerbation of the cholera epidemic. Comparison of rainfall and epidemiological patterns revealed that the temporal dynamics of precipitation, which was abrupt and heavy, was presumably the determining factor. Analysis of the SST gradient showed that the Atlantic Ocean SST variability in 2005 differed from that of 2002 to 2004, a result of a prominent Atlantic meridional mode. The influence of this intense precipitation on cholera transmission over a densely populated and crowded region was detectable for both Dakar and Thiès, Senegal. Thus, high resolution rainfall forecasts at subseasonal time scales should provide a way forward for an early warning system in Africa for cholera and, thereby, trigger epidemic preparedness. Clearly, attention must be paid to both natural and human induced environmental factors to devise appropriate action to prevent cholera and other waterborne disease epidemics in the region. PMID:22952995

  18. Immunization coverage and social differentiation in urban Senegal.

    PubMed Central

    Fassin, D; Jeannee, E

    1989-01-01

    We studied sociocultural factors associated with immunization coverage among a random sample of 500 mothers in the underprivileged suburbs of Dakar, Senegal. Factors associated with immunization of children under age 5 were maternal educational level and socioeconomic conditions (especially husband's regular salary); maternal age on arrival in town was more influential than total number of resident years in town; no effect of ethnicity was evident. PMID:2929817

  19. Cholera Outbreak in Senegal in 2005: Was Climate a Factor?

    PubMed Central

    Constantin de Magny, Guillaume; Thiaw, Wassila; Kumar, Vadlamani; Manga, Noël M.; Diop, Bernard M.; Gueye, Lamine; Kamara, Mamina; Roche, Benjamin; Murtugudde, Raghu; Colwell, Rita R.

    2012-01-01

    Cholera is an acute diarrheal illness caused by Vibrio cholerae and occurs as widespread epidemics in Africa. In 2005, there were 31,719 cholera cases, with 458 deaths in the Republic of Senegal. We retrospectively investigated the climate origin of the devastating floods in mid-August 2005, in the Dakar Region of Senegal and the subsequent outbreak of cholera along with the pattern of cholera outbreaks in three other regions of that country. We compared rainfall patterns between 2002 and 2005 and the relationship between the sea surface temperature (SST) gradient in the tropical Atlantic Ocean and precipitation over Senegal for 2005. Results showed a specific pattern of rainfall throughout the Dakar region during August, 2005, and the associated rainfall anomaly coincided with an exacerbation of the cholera epidemic. Comparison of rainfall and epidemiological patterns revealed that the temporal dynamics of precipitation, which was abrupt and heavy, was presumably the determining factor. Analysis of the SST gradient showed that the Atlantic Ocean SST variability in 2005 differed from that of 2002 to 2004, a result of a prominent Atlantic meridional mode. The influence of this intense precipitation on cholera transmission over a densely populated and crowded region was detectable for both Dakar and Thiès, Senegal. Thus, high resolution rainfall forecasts at subseasonal time scales should provide a way forward for an early warning system in Africa for cholera and, thereby, trigger epidemic preparedness. Clearly, attention must be paid to both natural and human induced environmental factors to devise appropriate action to prevent cholera and other waterborne disease epidemics in the region. PMID:22952995

  20. The Senegal Project: A Cultural Foods Unit for Middle School Students

    ERIC Educational Resources Information Center

    Nelson, Diane

    2011-01-01

    The Senegal Project is the culminating project in a unit on cultural foods in an 8th grade family and consumer sciences (FCS) course. Initially, students take a quick world tour by studying and cooking foods from Mexico, Italy, China, and India followed by a "more depth and less breadth" study of Senegal, a country with a culture vastly different…

  1. Interrelationships of Non-Formal Mother Tongue Education and Citizenship in Guinea and Senegal

    ERIC Educational Resources Information Center

    Clemons, Andrea; Yerende, Eva

    2009-01-01

    Guinea and Senegal are multilingual countries that use French as a language of instruction in the formal educational sector with some significant exceptions. As in many other African countries, such exceptions in Guinea and Senegal, use local African languages primarily in the non-formal sector for a variety of purposes, such as adult literacy and…

  2. The management of the Diama reservoir (Senegal River)

    NASA Astrophysics Data System (ADS)

    Duvail, S.; Hamerlynck, O.

    2003-04-01

    The Senegal River is regulated by 2 dams built in the 1980's by the "Organisation pour la Mise en Valeur du fleuve Sénégal" (OMVS), a river basin management organisation grouping Mali, Senegal and Mauritania. The initial objectives of OMVS, which were to regulate the Senegal flows in order to develop irrigated agriculture, produce hydropower and facilitate river navigation has been only partially met. The maintenance of the annual flood by the upstream dam (Manantali), initially to be phased out when irrigated agriculture would have replaced the traditional recession agriculture, is now scheduled to continue indefinitely on the basis of socio-economic and environmental concerns. This change of mindset has however not affected the management of the downstream dam (Diama). Initially conceived as a salt-wedge dam, its function evolved to a reservoir dam with a high and constant water level. During the dry season, the water level is maintained high and constant in order to reduce the pumping costs for the irrigated agriculture in the delta. During the flood season (July-October) the dam is primarily managed for risk avoidance: limit flooding downstream of the dam (especially the city of St. Louis) and secure the infrastructure of the dam itself. The permanent freshwater reservoir lake has adverse effects on ecosystems, on human and animal health and a high social cost for the traditional stakeholders of the deltaic floodplain (fishermen, livestock keepers and gatherers). Upstream of the reservoir there is an excess of stagnant freshwater and managers are confronted with the development of invasive species while substantial downstream flooding is essential for the estuarine ecosystems and local livelihoods. The presentation will review the different approaches to the management of the Diama reservoir and proposes different management scenarios and compares their economical, environmental, and social costs and benefits.

  3. The Origin and Evolutionary History of HIV-1 Subtype C in Senegal

    PubMed Central

    Jung, Matthieu; Leye, Nafissatou; Vidal, Nicole; Fargette, Denis; Diop, Halimatou; Toure Kane, Coumba; Gascuel, Olivier; Peeters, Martine

    2012-01-01

    Background The classification of HIV-1 strains in subtypes and Circulating Recombinant Forms (CRFs) has helped in tracking the course of the HIV pandemic. In Senegal, which is located at the tip of West Africa, CRF02_AG predominates in the general population and Female Sex Workers (FSWs). In contrast, 40% of Men having Sex with Men (MSM) in Senegal are infected with subtype C. In this study we analyzed the geographical origins and introduction dates of HIV-1 C in Senegal in order to better understand the evolutionary history of this subtype, which predominates today in the MSM population Methodology/Principal Findings We used a combination of phylogenetic analyses and a Bayesian coalescent-based approach, to study the phylogenetic relationships in pol of 56 subtype C isolates from Senegal with 3,025 subtype C strains that were sampled worldwide. Our analysis shows a significantly well supported cluster which contains all subtype C strains that circulate among MSM in Senegal. The MSM cluster and other strains from Senegal are widely dispersed among the different subclusters of African HIV-1 C strains, suggesting multiple introductions of subtype C in Senegal from many different southern and east African countries. More detailed analyses show that HIV-1 C strains from MSM are more closely related to those from southern Africa. The estimated date of the MRCA of subtype C in the MSM population in Senegal is estimated to be in the early 80's. Conclusions/Significance Our evolutionary reconstructions suggest that multiple subtype C viruses with a common ancestor originating in the early 1970s entered Senegal. There was only one efficient spread in the MSM population, which most likely resulted from a single introduction, underlining the importance of high-risk behavior in spread of viruses. PMID:22470456

  4. Revolution, Modernity and (Trans)National Shi`i Islam: Rethinking Religious Conversion in Senegal.

    PubMed

    Leichtman, Mara A

    2009-07-01

    The establishment of a Shi`i Islamic network in Senegal is one alternative to following the country's dominant Sufi orders. I examine Senegalese conversion narratives and the central role played by the Iranian Revolution, contextualizing life stories (trans)nationally in Senegal's political economy and global networks with Iran and Lebanon. Converts localize foreign religious ideologies into a 'national' Islam through the discourse that Shi`i education can bring peace and economic development to Senegal. Senegalese Shi`a perceive that proselytizing, media technologies, and Muslim networking can lead to social, cultural and perhaps even political change through translating the Iranian Revolution into a non-violent reform movement. PMID:23833329

  5. Vegetation impoverishment despite greening: a case study from central Senegal

    USGS Publications Warehouse

    Herrmann, Stefanie M.; Tappan, G. Gray

    2013-01-01

    Recent remote sensing studies have documented a greening trend in the semi-arid Sahel and Sudan zones of West Africa since the early 1980s, which challenges the mainstream paradigm of irreversible land degradation in this region. What the greening trend means on the ground, however, has not yet been explored. This research focuses on a region in central Senegal to examine changes in woody vegetation abundance and composition in selected sites by means of a botanical inventory of woody vegetation species, repeat photography, and perceptions of local land users. Despite the greening, an impoverishment of the woody vegetation cover was observed in the studied sites, indicated by an overall reduction in woody species richness, a loss of large trees, an increasing dominance of shrubs, and a shift towards more arid-tolerant, Sahelian species since 1983. Thus, interpretation of the satellite-derived greening trend as an improvement or recovery is not always justified. The case of central Senegal represents only one of several possible pathways of greening throughout the region, all of which result in similar satellite-derived greening signals.

  6. [Epidemiological surveillance and obstetrical dystocias surgery in Senegal].

    PubMed

    Bouillin, D; Fournier, G; Gueye, A; Diadhiou, F; Cissé, C T

    1994-01-01

    Maternal morbidity and mortality remain major problems of public health in developing countries. Having long been neglected, maternal health is now being included among the priorities of a large number of countries. The rate of maternal mortality in Senegal is 850 per 100,000 live births, among the highest in the world. The main causes of maternal mortality in Africa are obstructed labour and uterine rupture, hypertensive disorders of pregnancy, puerperal infection and haemorrhage. An epidemiological survey of obstetric disorders was initiated in 1992 in Senegal to characterise the requirements for surgical coverage during pregnancy and delivery. In 1992, the national rate of caesarean section was low (0.66% of estimated births). However, rates differed greatly between regions, and between rural and urban areas. The indications for caesarean section were classified into three groups, each corresponding to a different public health issue. The rate of maternal mortality associated with surgery was high: 4.7%, of which 29% during surgery and 71% post op. Perinatal prognosis was also poor, with a mortality rate of approximately 30%. There are only 18 reference obstetrics units functioning, and they give a very uneven coverage of the country. These finding have led to new guidelines to improve the quality and cover of maternal care over the coming years. PMID:7850191

  7. Coxiella burnetii in Humans and Ticks in Rural Senegal

    PubMed Central

    Mediannikov, Oleg; Fenollar, Florence; Socolovschi, Cristina; Diatta, Georges; Bassene, Hubert; Molez, Jean-François; Sokhna, Cheikh; Trape, Jean-François; Raoult, Didier

    2010-01-01

    Background Q fever is a worldwide zoonotic disease caused by Coxiella burnetii. Epidemiologically, animals are considered reservoirs and humans incidental hosts. Methodology/Principal Findings We investigated Q fever in rural Senegal. Human samples (e.g., sera, saliva, breast milk, feces) were screened in the generally healthy population of two villages of the Sine-Saloum region. Ticks were collected in four regions. Seroprevalence was studied by immunofluorescence, and all other samples were tested by two qPCR systems for detection of C. burnetii. Positive samples were genotyped (multispacer typing) by amplification and sequencing of three spacers. Strains were isolated by cell culture. We found that the seroprevalence may be as high as 24.5% (59 of 238 studied) in Dielmo village. We identified spontaneous excretion of C. burnetii by humans through faeces and milk. Hard and soft ticks (8 species) were infected in 0–37.6%. We identified three genotypes of C. burnetii. The previously identified genotype 6 was the most common in ticks in all studied regions and the only one found in human samples. Three strains of genotype 6 of C. burnetii were also recovered from soft tick Ornithodoros sonrai. Two other genotypes found in ticks, 35 and 36, were identified for the first time. Conclusions/Significance Q fever should be considered a significant public health threat in Senegal. Humans, similar to other mammals, may continuously excrete C. burnetii. PMID:20386603

  8. Tick-Borne Rickettsioses, Neglected Emerging Diseases in Rural Senegal

    PubMed Central

    Mediannikov, Oleg; Diatta, Georges; Fenollar, Florence; Sokhna, Cheikh; Trape, Jean-François; Raoult, Didier

    2010-01-01

    Background Rickettsioses are one of the most important causes of systemic febrile illness among travelers from developed countries, but little is known about their incidence in indigenous populations, especially in West Africa. Methodology/Principal Findings Overall seroprevalence evaluated by immunofluorescence using six rickettsial antigens (spotted fever and typhus group) in rural populations of two villages of the Sine-Saloum region of Senegal was found to be 21.4% and 51% for spotted fever group rickettsiae for Dielmo and Ndiop villages, respectively. We investigated the role of tick-borne rickettsiae as the cause of acute non-malarial febrile diseases in the same villages. The incidence of rickettsial DNA in 204 blood samples from 134 (62M and 72F) febrile patients negative for malaria was studied. DNA extracted from whole blood was tested by two qPCR systems. Rickettsial DNA was found in nine patients, eight with Rickettsia felis (separately reported). For the first time in West Africa, Rickettsia conorii was diagnosed in one patient. We also tested 2,767 Ixodid ticks collected in two regions of Senegal (Niakhar and Sine-Saloum) from domestic animals (cows, sheep, goats, donkeys and horses) by qPCR and identified five different pathogenic rickettsiae. We found the following: Rickettsia aeschlimannii in Hyalomma marginatum rufipes (51.3% and 44.8% in Niakhar and Sine-Saloum region, respectively), in Hyalomma truncatum (6% and 6.8%) and in Rhipicephalus evertsi evertsi (0.5%, only in Niakhar); R. c. conorii in Rh. e. evertsi (0.4%, only in Sine-Saloum); Rickettsia massiliae in Rhipicephalus guilhoni (22.4%, only in Niakhar); Rickettsia sibirica mongolitimonae in Hyalomma truncatum (13.5%, only in Sine-Saloum); and Rickettsia africae in Rhipicephalus evertsi evertsi (0.7% and 0.4% in Niakhar and Sine-Saloum region, respectively) as well as in Rhipicephalus annulatus (20%, only in Sine-Saloum). We isolated two rickettsial strains from H. truncatum: R. s

  9. Agricultural water and energy use in the Senegal River Valley

    NASA Astrophysics Data System (ADS)

    Masiyandima, M. C.; Sow, A.

    2015-12-01

    Assessment of the productivity of irrigation water is important measuring the performance of irrigation schemes especially in water scarce areas. Equally important for performance is the energy cost of providing water for irrigation. Sahel irrigation schemes are dependent on pumping water from rivers into a network of gravity operated channels. In the Senegal River valley in Senegal the cost of pumping water and for irrigation has been estimated to be 20-25% of total rice production costs. Irrigation schemes in the valley are characterized by low water productivity. We analysed rice production, irrigation water use and energy use for supplying irrigation water at Pont Gendarme, Ndiawar and Ngallenka MCA irrigation schemes in the Senegal River valley. For the 2013 rainfall season the mean yield ranged between 6 and 8t ha-1. Dry season yield ranged between 1.7 and 6.8t ha-1. Energy use for irrigation in the Ndiawar irrigation scheme was 8kg MJ-1 and 6.4kg MJ-1 in the 2013 and 2014 rainfall seasons respectively. In 2014 (rainfall season) energy productivity of irrigation water was 8.5, 8.0 and 16.4 kg MJ-1 at Ngallenka MCA, Ndiawar and Pont Gendarme respectively. Dry season (2014) energy productivity at Ndiawar and Pont Gendarme was 3.4 and 11.2kg MJ-1 respectively. Productivity of irrigation water was similar for all schemes (0.37kg m-3 at Pont Gendarme, 0.42kg m-3 at Ngallenka MCA, and 0.41kg m-3 Ndiawar). Energy use for the supply of irrigation water in the rainfall season ranged from 403 to 1,002MJ ha-1. Dry season irrigation energy use was 589MJ ha-1 Pont Gendarme and 331MJ ha-1 at Ndiawar. Reducing water use in these schemes through better water management will result in lower production costs and increased margins for the farmers. The observations from 2013 - 2014 highlight the importance of using both water and energy productivity to assess performance of irrigation schemes.

  10. Rapid evolution of water resources in the Senegal delta

    NASA Astrophysics Data System (ADS)

    Ngom, F. D.; Tweed, S.; Bader, J.-C.; Saos, J.-L.; Malou, R.; Leduc, C.; Leblanc, M.

    2016-09-01

    In recent decades major water developments have led to an agricultural transformation of the Senegal delta both in Senegal and Mauritania. This otherwise, semi-arid region of the Sahel band now has an abundant supply of freshwater all year round mostly used for irrigation and urban water supply, including for the capital cities of the two countries. Archives from the Landsat satellites and in-situ hydrographs were used in this paper to retrace and analyse the hydrological changes that have taken place in the region since the middle of the 20th century. The satellite archives indicate that the area covered by irrigation increased by one order of magnitude from 73 km2 in 1973 to ~ 770 km2 in 2010. The observed hydrological changes are complex, multi-faceted and often of great magnitude. If the water cycle was representative of natural conditions in the early 1980s, it is now representative of a heavily modified system controlled and impacted by human activities. The first hydraulic infrastructure was installed in 1947 to enable the Lake of Guiers to become the main water supply for Dakar. Two large dams were built on the Senegal River in the mid-1980s that modified the hydrological regime of the river by 1) preventing seawater intrusion, 2) raising the stage of the river and of Lake of Guiers and 3) moderating floods. Another recent hydrological change in the delta was the opening of river mouth in 2003, which has led to a reduction of the average water level while increasing the semi-diurnal tidal wave between the river mouth and Diama. Each phase of these river regime changes and each step of the irrigation expansion are expressed in localised changes in the physical groundwater system. Increasingly, the retroaction from the shallow aquifer systems is observed as a rise of the saline water table. This poses a threat to the environmental and agricultural value of the region, and the salinization of the soils. Mitigating actions for this threat are currently being

  11. Plasmodium falciparum In Vitro Resistance to Monodesethylamodiaquine, Dakar, Senegal, 2014

    PubMed Central

    Fall, Bécaye; Madamet, Marylin; Camara, Cheikhou; Amalvict, Rémy; Fall, Mansour; Nakoulima, Aminata; Diatta, Bakary; Diémé, Yaya; Wade, Boubacar

    2016-01-01

    We successfully cultured 36 Plasmodium falciparum isolates from blood samples of 44 malaria patients admitted to the Hôpital Principal de Dakar (Dakar, Senegal) during August–December 2014. The prevalence of isolates with in vitro reduced susceptibility was 30.6% for monodesethylamodiaquine, 52.8% for chloroquine, 44.1% for mefloquine, 16.7% for doxycycline, 11.8% for piperaquine, 8.3% for artesunate, 5.9% for pyronaridine, 2.8% for quinine and dihydroartemisinin, and 0.0% for lumefantrine. The prevalence of isolates with reduced in vitro susceptibility to the artemisinin-based combination therapy partner monodesethylamodiaquine increased from 5.6% in 2013 to 30.6% in 2014. Because of the increased prevalence of P. falciparum parasites with impaired in vitro susceptibility to monodesethylamodiaquine, the implementation of in vitro and in vivo surveillance of all artemisinin-based combination therapy partners is warranted. PMID:27088703

  12. [Dynamics of disease in Senegal: epidemiological transition or health transition?].

    PubMed

    Niang-Diene, A; Salem, G

    2015-08-01

    In Senegal, the evolution of disease as recorded by the public health care system confirms the preponderance of seeking care for infectious diseases (malaria, respiratory and diarrheal diseases) and reveals the emergence of chronic diseases. However, while the incidence of hypertension diagnosed by the public system increased from 14 to 81 per thousand inhabitants aged over 40, between 1995 and 2009, the diabetes appears only at 0.4‰, thus in contradiction with hospital data and general population surveys. For instance, diabetes prevalence was estimated at 10.4% in Saint-Louis in 2010 (8). This difference recalls the limitations of this data source as regards epidemiological information, but sheds light on the challenges facing the health care system, both in terms of detection, medical care, access to health care and treatment as well as cost recovery. PMID:25481256

  13. Plasmodium falciparum In Vitro Resistance to Monodesethylamodiaquine, Dakar, Senegal, 2014.

    PubMed

    Fall, Bécaye; Madamet, Marylin; Camara, Cheikhou; Amalvict, Rémy; Fall, Mansour; Nakoulima, Aminata; Diatta, Bakary; Diémé, Yaya; Wade, Boubacar; Pradines, Bruno

    2016-05-01

    We successfully cultured 36 Plasmodium falciparum isolates from blood samples of 44 malaria patients admitted to the Hôpital Principal de Dakar (Dakar, Senegal) during August-December 2014. The prevalence of isolates with in vitro reduced susceptibility was 30.6% for monodesethylamodiaquine, 52.8% for chloroquine, 44.1% for mefloquine, 16.7% for doxycycline, 11.8% for piperaquine, 8.3% for artesunate, 5.9% for pyronaridine, 2.8% for quinine and dihydroartemisinin, and 0.0% for lumefantrine. The prevalence of isolates with reduced in vitro susceptibility to the artemisinin-based combination therapy partner monodesethylamodiaquine increased from 5.6% in 2013 to 30.6% in 2014. Because of the increased prevalence of P. falciparum parasites with impaired in vitro susceptibility to monodesethylamodiaquine, the implementation of in vitro and in vivo surveillance of all artemisinin-based combination therapy partners is warranted. PMID:27088703

  14. Lunar and daily spawning rhythms of Senegal sole Solea senegalensis.

    PubMed

    Oliveira, C; Dinis, M T; Soares, F; Cabrita, E; Pousão-Ferreira, P; Sánchez-Vázquez, F J

    2009-07-01

    A periodicity of 29 days was observed in spawning rhythms in Senegal sole Solea senegalensis, with an acrophase around the last quarter and the new moon. In both spring and autumn, a very marked nocturnal spawning rhythm was registered, with spawning beginning after dusk and the acrophase occurring around 2300 hours. When the photoperiod was artificially extended (from 10L:14D to 14L:10D), S. senegalensis synchronized to the new photoperiod: spawning took place after the new 'dusk', the beginning gradually shifting from 2100 to 2300 hours and the acrophase from 2325 to 0032 hours. Under continuous light conditions, fish sustained rhythmicity for 2 days, with an acrophase at 2249 hours, which suggested the existence of an endogenous pacemaker controlling the daily spawning rhythm. These findings provided new insights for better understanding the reproductive physiology of this species and for optimizing the timing protocols of egg collection and larvae production in S. senegalensis aquaculture. PMID:20738482

  15. Zika Virus Emergence in Mosquitoes in Southeastern Senegal, 2011

    PubMed Central

    Diallo, Diawo; Sall, Amadou A.; Diagne, Cheikh T.; Faye, Oumar; Faye, Ousmane; Ba, Yamar; Hanley, Kathryn A.; Buenemann, Michaela; Weaver, Scott C.; Diallo, Mawlouth

    2014-01-01

    Background Zika virus (ZIKV; genus Flavivirus, family Flaviviridae) is maintained in a zoonotic cycle between arboreal Aedes spp. mosquitoes and nonhuman primates in African and Asian forests. Spillover into humans has been documented in both regions and the virus is currently responsible for a large outbreak in French Polynesia. ZIKV amplifications are frequent in southeastern Senegal but little is known about their seasonal and spatial dynamics. The aim of this paper is to describe the spatio-temporal patterns of the 2011 ZIKV amplification in southeastern Senegal. Methodology/Findings Mosquitoes were collected monthly from April to December 2011 except during July. Each evening from 18∶00 to 21∶00 hrs landing collections were performed by teams of 3 persons working simultaneously in forest (canopy and ground), savannah, agriculture, village (indoor and outdoor) and barren land cover sites. Mosquitoes were tested for virus infection by virus isolation and RT-PCR. ZIKV was detected in 31 of the 1,700 mosquito pools (11,247 mosquitoes) tested: Ae. furcifer (5), Ae. luteocephalus (5), Ae. africanus (5), Ae. vittatus (3), Ae. taylori, Ae. dalzieli, Ae. hirsutus and Ae. metallicus (2 each) and Ae. aegypti, Ae. unilinaetus, Ma. uniformis, Cx. perfuscus and An. coustani (1 pool each) collected in June (3), September (10), October (11), November (6) and December (1). ZIKV was detected from mosquitoes collected in all land cover classes except indoor locations within villages. The virus was detected in only one of the ten villages investigated. Conclusions/Significance This ZIKV amplification was widespread in the Kédougou area, involved several mosquito species as probable vectors, and encompassed all investigated land cover classes except indoor locations within villages. Aedes furcifer males and Aedes vittatus were found infected within a village, thus these species are probably involved in the transmission of Zika virus to humans in this environment. PMID

  16. Traditional leafy vegetables in Senegal: diversity and medicinal uses.

    PubMed

    Mathieu, Gueye; Meissa, Diouf

    2007-01-01

    Six administrative regions of Senegal were investigated. Forty species of vegetable leaves which are traditionally consumed in Senegal have been inventoried. All species are members of twenty-one families the most numerous of which are Amaranthaceae Juss., Malvaceae Juss., Moraceae Link., the Papilionaceae Giseke and Tiliaceae Juss. The species are subdivided into three groups: cultivated leafy vegetables, plants gathered annually, perennial sub-ligneous and ligneous species. The gathered species represent 67.5% of the inventory, 40.7% of which is ligneous. Cultivated species account for 32.5% of the inventory. The species are consumed for their medicinal properties, nutritive value and eating habits linked to specific ethnic traditions. During the drought years, with the scarcity of main food (millet, mays) consumption of leafy vegetables is high. All species reported except Sesuvium portulacastrum L. are consumed like vegetable herbs. The species of Hibiscus are eaten in spinach and condiment form while Sesuvium portulacastrum L is cooked in salad. Of the forty species examined, eleven are widely consumed. Within the entire study area, Hibiscus sabdariffa predominates among species consumed, followed by Moringa oleifera Lam. and Senna obtusifolia Link. A high consumption level of some species like amarante, Corchorus tridens L., Corchorus aestuans L., Leptadenia hastata Decne. and Vigna unguiculata (L.) Walp is confined to certain areas. In addition to their consumption as vegetables, the medicinal uses of 57.5% of these is of primary importance. The most commonly exploited parts are, respectively, leaf (40%), roots (20%), and bark (13.3%). Among the numerous pathologies treated, abscess, constipation, and rheumatism are predominant followed by aphrodisiac uses. The Amaranthus spp. L., Leptadenia hastata Decne., Senna obtusifolia Link., Adansonia digitata L. and Tamarindus indica L. are species with multiple medicinal uses. PMID:20161914

  17. Correlation between NDVI and the annual groundnut yield in Senegal

    NASA Astrophysics Data System (ADS)

    Martin, Samuel; Borondo, Javier; Morales, Alfredo; Losada, Juan Carlos; Tarquis, Ana M.; Benito, Rosa M.

    2016-04-01

    A key strategy to assert and minimize risk in agriculture is to gather information about the factors that may affect the production. That is why remote sensing measurements have become a fundamental tool in this area. Between all the existing measurements, the Normalized Difference Vegetation Index (NDVI) is one of the most useful. The NDVI, which is computed using satellite images, takes into account the physicochemical mechanism of the photosynthesis in order to quantify the photosynthetic activity of a an area. A natural question that arises from the risk and hazard management point of view is if this index can help us estimate or even forecast the yield of a given harvest. Intuitively, this should be possible if a correlation between NDVI and yield is found. We have focused our study in the country of Senegal, where more than 70% of the work force is employed in the agricultural sector. Since Senegal is also one of the most important peanut oil producer and exporter, the crop we have chosen for this research is the peanut. The economic relevance of this product guarantees that a significant fraction of the soil will be used for this crop. We have worked with NDVI data computed from satellite images taken with the MODIS instrument of the Terra satellite launched by NASA on 1999. In order to explore the correlations with agricultural yield, we have also retrieved production data from the Food and Agriculture Organization (FAO) of the United Nations. The results we have obtained suggest that a linear correlation between NDVI and yield do exist; moreover, this correlation can be enhanced if, instead of yearly averages of NDVI, the NDVI corresponding to a smaller time period -which lies within the growing season - is taken. Acknowledgements First author acknowledges the Research Grant obtained from CEIGRAM in 2015

  18. Water management in the Senegal River Delta: a continuing uncertainty

    NASA Astrophysics Data System (ADS)

    Mietton, M.; Dumas, D.; Hamerlynck, O.; Kane, A.; Coly, A.; Duvail, S.; Pesneaud, F.; Baba, M. L. O.

    2007-11-01

    Water management is the driving force behind the productivity of the ecosystems of the Senegal River Estuary and floodplains. It is dependent on human decision-making, but has been separated from the River's flooding since the building of the Diama Dam. The current objectives of the Office de Mise en Valeur du fleuve Sénégal (OMVS: Senegal River Development Agency) are mainly turned towards the development of irrigated agriculture on the former floodplains and since 2002 the production of hydroelectric power at Manantali. In October 2003, a four-metre-wide runoff canal, which quickly widened into a breach several hundred metres across, was dug in the Barbary Spit area to protect the city of Saint-Louis from heavy flooding. The hydraulic quality of the area downstream from the dam has improved to the extent that there is no longer any flooding there, but as the management of the dams concerns only the section of the river between Manantali and Diama, a certain amount of flood risk probably still persists. The intrusion of seawater into the estuary is also threatening ecosystems and fresh water supplies, and abruptly altering agricultural practices such as fruit and vegetable growing in the Gandiolais district. When added to the tentative efforts to coordinate the management of the two dams, with no management objective downstream from Diama, such permanent modifications impose serious constraints on the managers and residents of the lower delta. This paper presents an overview of the constraints and uncertainties at different levels and scales. This wholly human-wrought environment can be considered as a learning experience, where a large number of variables need to be monitored closely and an ongoing process of participatory analysis should be backed up by multidisciplinary research.

  19. Antiatherosclerotic and Cardioprotective Potential of Acacia senegal Seeds in Diet-Induced Atherosclerosis in Rabbits

    PubMed Central

    Ram, Heera; Jatwa, Rameshwar; Purohit, Ashok

    2014-01-01

    Acacia senegal L. (Fabaceae) seeds are essential ingredient of “Pachkutta,” a specific Rajasthani traditional food. The present study explored antiatherosclerotic and cardioprotective potential of Acacia senegal seed extract, if any, in hypercholesterolemic diet-induced atherosclerosis in rabbits. Atherosclerosis in rabbits was induced by feeding normal diet supplemented with oral administration of cholesterol (500 mg/kg body weight/day mixed with coconut oil) for 15 days. Circulating total cholesterol (TC), HDL-cholesterol (HDL-C), LDL-cholesterol (LDL-C), triglycerides, and VLDL-cholesterol (VLDL-C) levels; atherogenic index (AI); cardiac lipid peroxidation (LPO); planimetric studies of aortal wall; and histopathological studies of heart, aorta, kidney, and liver were performed. Apart from reduced atherosclerotic plaques in aorta (6.34 ± 0.72) and increased lumen volume (51.65 ± 3.66), administration with ethanolic extract of Acacia senegal seeds (500 mg/kg/day, p.o.) for 45 days to atherosclerotic rabbits significantly lowered serum TC, LDL-C, triglyceride, and VLDL-C levels and atherogenic index as compared to control. Atherogenic diet-induced cardiac LPO and histopathological abnormalities in aorta wall, heart, kidney, and liver were reverted to normalcy by Acacia senegal seed extract administration. The findings of the present study reveal that Acacia senegal seed extract ameliorated diet-induced atherosclerosis and could be considered as lead in the development of novel therapeutics. PMID:25544897

  20. [Ethnic dimension to migration in the Senegal river valley].

    PubMed

    Traore, S

    1993-08-01

    Studies of the factors determining migratory patterns in the Senegal River Valley usually stress the importance of economic factors related to colonial domination. But when cultural factors and the social relations governing them are examined in a comparative study of ethnic groups, distinct population subgroups may be revealed to have differential migratory patterns. The Soninka and the Poular, two groups highly affected by migration, were chosen for an analysis of the impact of specific historical experiences on migratory behavior. A historical analysis of colonial archives and anthropological and historical monographs and the 1982-83 "Survey of Migration in the Valley of the Senegal River" provided data. The survey indicated that Soninka and Poular migratory patterns differed from each other, but that both differed from the migratory patterns of all other ethnic groups in the region. Soninka migration is international and oriented primarily toward Europe. It has recently become more intense than that of the poular. The determinants of migration in the two groups appear related more to the structure of households than to lack of educational and health facilities or even of food at the village level. Pastoral life and its associated beliefs and religious ideology appear to have been the principal determinants of precolonial movement among the Poular, while Soninka migration responded more to competition over control of manpower. Itinerant commercial activity was coupled with use of slave labor to ensure food production. But the suppression of slavery and crises of subsistence aggravated by colonial policy provoked ever more distant migration, which found a focus in the French demand for labor after World War II. Migration as an alternative does not appear to have been as significant for the Poular until more recently, when subsistence agriculture and the sale of animals were no longer sufficient to cover monetary needs. Male migration among the Soninka is a

  1. Revolution, Modernity and (Trans)National Shi`i Islam: Rethinking Religious Conversion in Senegal

    PubMed Central

    Leichtman, Mara A.

    2013-01-01

    The establishment of a Shi`i Islamic network in Senegal is one alternative to following the country's dominant Sufi orders. I examine Senegalese conversion narratives and the central role played by the Iranian Revolution, contextualizing life stories (trans)nationally in Senegal's political economy and global networks with Iran and Lebanon. Converts localize foreign religious ideologies into a ‘national’ Islam through the discourse that Shi`i education can bring peace and economic development to Senegal. Senegalese Shi`a perceive that proselytizing, media technologies, and Muslim networking can lead to social, cultural and perhaps even political change through translating the Iranian Revolution into a non-violent reform movement. PMID:23833329

  2. [Evaluation of the cost of stroke management in Dakar, Senegal].

    PubMed

    Touré, K; Ndiaye, N M; Sène Diouf, F; Ndiaye, M; Diallo, A K; Ndao, A K; Thiam, A; Diagne, M; Diop, A G; Ndiaye, M N; Ndiaye, I P

    2005-11-01

    The purpose of this one-year cross-sectional study conducted in 1997 was to estimate the direct cost of stroke management in the Neurology Department of Fann University Hospital in Dakar, Senegal. Data were collected about the type of care services required and related spending. Cost analysis was made in CFA Francs (CFAF), the Senegalese currency (1 USD = 500 CFAF in 1997). A total of 1260 patients were hospitalized in the department including 383 for stroke (30.4%). Mean age was 60.8 +/- 14.2 years and men accounted for 49.2% of the population. The mortality rate was 46.2% among hospitalized patients. A total of 33,573 medical acts were carried out including 12,052 (35.9%) for stroke management. The direct cost of stroke management was 32,614,442 CFAF with a mean cost of 78,426 CFAF per patient. The cost was 18,839 CFAF in the patient care unit (57.8%) and 4,954,635 CFAF in the neuroradiology unit (15.2%). The cost of health care personnel was 19,373,172 CFAF (59.4%) and the cost for drugs and other medical products was 8,253,246 CFAF. Health education programs aimed at increasing awareness of risk factors are needed to reduce the cost of stroke management in this difficult economic period. PMID:16465816

  3. Diaspora, faith, and science: building a Mouride hospital in Senegal.

    PubMed

    Foley, Ellen E; Babou, Cheikh Anta

    2011-01-01

    This article examines a development initiative spearheaded by the members of a transnational diaspora – the creation of a medical hospital in the holy city of Touba in central Senegal. Although the construction of the hospital is decidedly a philanthropic project, Hôpital Matlaboul Fawzaini is better understood as part of the larger place-making project of the Muridiyya and the pursuit of symbolic capital by a particular Mouride "dahira". The "dahira's" project illuminates important processes of forging global connections and transnational localities, and underscores the importance of understanding the complex motivations behind diaspora development. The hospital's history reveals the delicate negotiations between state actors and diaspora organizations, and the complexities of public–private partnerships for development. In a reversal of state withdrawal in the neo-liberal era, a diaspora association was able to wrest new financial commitments from the state by completing a large infrastructure project. Despite this success, we argue that these kinds of projects, which are by nature uneven and sporadic, reflect particular historical conjunctures and do not offer a panacea for the failure of state-led development. PMID:21186681

  4. Energy assessment of Ivory Coast, Morocco, Nigeria, and Senegal

    SciTech Connect

    Ghirardi, A.; Sathaye, J.; Goering, P.

    1986-11-01

    This report is an overview of the energy market in four West African countries: The Ivory Coast, Morocco, Nigeria, and Senegal. We feel these countries are representative of the West African region. Together they account for 75% of the total energy use in West Africa, 78% of GDP, and 76% of population. The purpose of the study is to analyze the evolution of energy demand in the context of the general socio-economic background of the region. The study also examines energy supply and trade related to the energy sector. The analysis focuses on the study of commercial fuels. Although we have reviewed studies of wood, solar, wind, and agricultural residues, we leave out detailed discussions of these non-commercial energy forms. The first part of the report is an assessment of the trends in energy demand in the four study countries. We discuss the main factors driving energy demand sector by sector. This is followed by a review of the primary energy resources of the countries, and of the capacity for production of secondary fuels. The last section looks at energy trade, with particular emphasis on the role of the United States.

  5. Legislating Change? Responses to Criminalizing Female Genital Cutting in Senegal

    PubMed Central

    Shell-Duncan, Bettina; Hernlund, Ylva; Wander, Katherine; Moreau, Amadou

    2014-01-01

    Although the international community has recently promoted legislation as an important reform strategy for ending female genital cutting (FGC), there exist divergent views on its potential effects. Supporters argue that legal prohibition of FGC has a general deterrent effect, while others argue legislation can be perceived as coercive, and derail local efforts to end the practice. This study examines the range of responses observed in rural Senegal, where a 1999 anti-FGC law was imposed on communities in which the practice was being actively contested and targeted for elimination. Drawing on data from a mixed-methods study, we analyze responses in relation to two leading theories on social regulation, the law and economics and law and society paradigms, which make divergent predictions on the interplay between social norms and legal norms. Among supporters of FGC, legal norms ran counter to social norms, and did little to deter the practice, and in some instances incited reactance or drove the practice underground. Conversely, where FGC was being contested, legislation served to strengthen the stance of those contemplating or favoring abandonment. We conclude that legislation can complement other reform strategies by creating an “enabling environment” that supports those who have or wish to abandon FGC. PMID:24771947

  6. High mortality from snakebite in south-eastern Senegal.

    PubMed

    Trape, J F; Pison, G; Guyavarch, E; Mane, Y

    2001-01-01

    Over 24 years, from 1976 to 1999, we conducted a prospective study of overall and cause-specific mortality among the population of 42 villages of south-eastern Senegal. Of 4228 deaths registered during this period, 26 were caused by snakebite, 4 by invertebrate stings and 8 by other wild or domestic animals. The average annual mortality rate from snakebite was 14 deaths per 100,000 population. Among persons aged > or = 1 year, 0.9% (26/2880) of deaths were caused by snakebite and this cause represented 28% (26/94) of total deaths by accidents. We also investigated the snake fauna of the area. Of 1280 snakes belonging to 34 species that were collected, one-third were dangerous and the proportion of Viperidae, Elapidae and Atractaspidae was 23%, 11% and 0.6%, respectively. The saw-scaled viper Echis ocellatus was the most abundant species (13.6%). Other venomous species were Causus maculatus (6.5%), Naja katiensis (5.5%), Bitis arietans (2.7%), Elapsoidea trapei (2.4%), Naja nigricollis (1.2%), Naja melanoleuca (1.1%), Atractaspis aterrima (0.4%), Dendroaspis polylepis (0.3%) and Naja haje (0.1%). PMID:11579888

  7. Genetic characterization of Moniezia species in Senegal and Ethiopia.

    PubMed

    Diop, Gora; Yanagida, Tetsuya; Hailemariam, Zerihun; Menkir, Sissay; Nakao, Minoru; Sako, Yasuhito; Ba, Cheikh Tidiane; Ito, Akira

    2015-10-01

    Genetic diversity of Moniezia spp. from domestic ruminants in Senegal and Ethiopia was investigated based on the nucleotide sequences of mitochondrial cytochrome c oxidase subunit 1 (cox1) and nuclear small subunit ribosomal RNA gene (SSU rDNA). A total of 64 adult tapeworms were collected from sheep, goat and cattle, and the tapeworms from cattle were all morphologically identified as Moniezia benedeni. On the other hand, the tapeworms obtained from sheep and goat were identified as Moniezia expansa or could not be identified because of the lack of diagnostic morphologic character, i.e. interproglottidal glands (IPGs). Phylogenetic analysis based on cox1 gene sequences revealed that the worms from sheep/goat and cattle formed distinct clades, and three mitochondrial lineages were confirmed within the sheep/goat tapeworms. The maximum pairwise divergences among the three mitochondrial linages were about 3% in cox1 and 0.1% in SSU rDNA, while that between the worms from sheep/goat and cattle reached 13% in cox1 and 2.7% in SSU rDNA. All of the three mitochondrial lineages contained tapeworms morphologically identified as M. expansa, and the tapeworms without IPGs were confirmed in one of the three lineages, indicating the tapeworms without IPGs were also M. expansa. PMID:25752566

  8. Health-related media use among youth audiences in Senegal.

    PubMed

    Glik, Deborah; Massey, Philip; Gipson, Jessica; Dieng, Thierno; Rideau, Alexandre; Prelip, Michael

    2016-03-01

    Lower- and middle-income countries (LMICs) are experiencing rapid changes in access to and use of new internet and digital media technologies. The purpose of this study was to better understand how younger audiences are navigating traditional and newer forms of media technologies, with particular emphasis on the skills and competencies needed to obtain, evaluate and apply health-related information, also defined as health and media literacy. Sixteen focus group discussions were conducted throughout Senegal in September 2012 with youth aged 15-25. Using an iterative coding process based on grounded theory, four themes emerged related to media use for health information among Senegalese youth. They include the following: (i) media utilization; (ii) barriers and conflicts regarding media utilization; (iii) uses and gratifications and (iv) health and media literacy. Findings suggest that Senegalese youth use a heterogeneous mix of media platforms (i.e. television, radio, internet) and utilization often occurs with family members or friends. Additionally, the need for entertainment, information and connectedness inform media use, mostly concerning sexual and reproductive health information. Importantly, tensions arise as youth balance innovative and interactive technologies with traditional and conservative values, particularly concerning ethical and privacy concerns. Findings support the use of multipronged intervention approaches that leverage both new media, as well as traditional media strategies, and that also address lack of health and media literacy in this population. Implementing health-related interventions across multiple media platforms provides an opportunity to create an integrated, as opposed to a disparate, user experience. PMID:25113152

  9. [Adult purulent meningitis caused by Streptococcus pneumoniae in Dakar, Senegal].

    PubMed

    Manga, N M; Ndour, C T; Diop, S A; Ka-Sall, R; Dia, N M; Seydi, M; Soumare, M; Diop, B M; Sow, A I; Sow, P S

    2008-12-01

    The purpose of this retrospective study was to describe epidemiological, clinical, bacteriological and outcome features of purulent meningitis caused by Streptococcus pneumoniae in adult patients hospitalized in the infectious diseases clinic of the Fann University Hospital in Dakar, Senegal from 1995 to 2004. A total of 73 cases of pneumococcal meningitis were recorded during the study period. Streptococcus pneumoniae was the second cause of purulent meningitis after meningococcal infection. Sickle-cell disease (n=3) and HIV infection (n=9) were the main underlying factors and pneumonia was the main portal of entry into the CNS (51.8%). Coma was a frequent complication (61.6%). Penicillin-nonsusceptible Streptococcus pneumoniae (PNSP) accounted for 27.3% of isolated strains. However strains were sensitive to third-generation cephalosporin (100%) and chloramphenicol (68.2%) which were the most frequently used antibiotics. The mortality rate was 69.8% and neurological complications occurred in 13.7% of patients. The main unfavorable prognostic factors were cardiovascular collapse and/or coma at the time of admission and detection of pneumococcal strains by direct examination of CSF. The high mortality of pneumococcal meningitis in adult patients in Dakar shows the need to improve intensive care facilities and the growing incidence of PNSP underlines the requirement for better control of antibiotic prescription. PMID:19639833

  10. Oceanic influence on seasonal malaria outbreaks over Senegal and Sahel

    NASA Astrophysics Data System (ADS)

    Diouf, Ibrahima; Rodríguez de Fonseca, Belen; Deme, Abdoulaye; Cisse Cisse, Moustapha; Ndione Ndione, Jaques-Andre; Gaye, Amadou T.; Suarez, Roberto

    2015-04-01

    Beyond assessment and analysis of observed and simulated malaria parameters, this study is furthermore undertaken in the framework of predictability of malaria outbreaks in Senegal and remote regions in Sahel, which are found to take place two months after the rainy season. The predictors are the sea surface temperature anomalous patterns at different ocean basins mainly over the Pacific and Atlantic as they are related to changes in air temperature, humidity, rainfall and wind. A relationship between El Niño and anomalous malaria parameters is found. The malaria parameters are calculated with the Liverpool Malaria Model (LMM) using meteorological datasets from different reanalysis products. A hindcast of these parameters is performed using the Sea Surface temperature based Statistical Seasonal ForeCAST (S4CAST) model developed at UCM in order to predict malaria parameters some months in advance. The results of this work will be useful for decision makers to better access to climate forecasts and application on malaria transmission risk.

  11. Insectivory of savanna chimpanzees (Pan troglodytes verus) at Fongoli, Senegal.

    PubMed

    Bogart, Stephanie L; Pruetz, Jill D

    2011-05-01

    Little is known about the behavior of chimpanzees living in savanna-woodlands, although they are of particular interest to anthropologists for the insight they can provide regarding the ecological pressures affecting early hominins living in similar habitats. Fongoli, Senegal, is the first site where savanna chimpanzees have been habituated for observational data collection and is the hottest and driest site where such observation of chimpanzees occurs today. Previously, indirect evidence suggested these chimpanzees consumed termites throughout the year, an unusual occurrence for western and eastern chimpanzees. Although meat eating by chimpanzees continues to receive much attention, their use of invertebrate prey has received less emphasis in scenarios of hominin evolution. Here, we further examine the invertebrate diet of Fongoli chimpanzees using direct observational methods and accounting for potential environmental influences. Termite feeding positively correlated with high temperatures. Fongoli chimpanzees spend more time obtaining termites than any other chimpanzee population studied, and this extensive insectivory contributes to the list of distinctive behaviors they display relative to chimpanzees living in more forested habitats. We suggest that savanna chimpanzees at Fongoli differ significantly from chimpanzees elsewhere as a result of the selective pressures characterizing their harsh environment, and this contrast provides an example of a viable referential model for better understanding human evolution. Specifically, our results support the hypotheses that invertebrate prey may have figured more prominently into the diet of early hominins in similar habitats, especially given that invertebrates are an important source of protein and other essential nutrients in a highly seasonal environment. PMID:21484757

  12. Glycemic Control in a Clinic-Based Sample of Diabetics in M'Bour Senegal

    ERIC Educational Resources Information Center

    BeLue, Rhonda; Ndiaye, Khadidiatou; NDao, Fatou; Ba, Fatou Niass Niang; Diaw, Mor

    2016-01-01

    Background: Sub-Saharan Africa (SSA) including Senegal is faced with a significant and increasing burden of type 2 diabetes. However, little information is available about diabetes management among Senegalese diabetics. Purpose: The current study aims to describe the level of glycemic control among a convenience sample of diabetics who receive…

  13. Implementation of the Integrated Early Childhood Policy in Senegal. Early Childhood and Family Policy Series.

    ERIC Educational Resources Information Center

    Rayna, Sylvie

    As part of a UNESCO-sponsored series of studies examining how integrated and coordinated early childhood policies are implemented, this case study focuses on Senegal's integrated early childhood policy. The case study examines the context for policy development and analyzes the structure and resources of the Ministry for the Family and Early…

  14. Cognitive Skills among Children in Senegal: Disentangling the Roles of Schooling and Family Background

    ERIC Educational Resources Information Center

    Glick, Peter; Sahn, David E.

    2009-01-01

    We use unique data to estimate the determinants of cognitive ability among 14-17-year olds in Senegal. Unlike standard school-based samples, tests were administered to current students as well as to children no longer--or never--enrolled. Years of schooling strongly affects cognitive skills, but conditional on years of school, parental education…

  15. Polyploidy can Confer Superiority to West African Acacia senegal (L.) Willd. Trees

    PubMed Central

    Diallo, Adja M.; Nielsen, Lene R.; Kjær, Erik D.; Petersen, Karen K.; Ræbild, Anders

    2016-01-01

    Polyploidy is a common phenomenon in the evolution of angiosperms. It has been suggested that polyploids manage harsh environments better than their diploid relatives but empirical data supporting this hypothesis are scarce, especially for trees. Using microsatellite markers and flow cytometry, we examine the frequency of polyploids and diploids in a progeny trial testing four different populations of Acacia senegal, a species native to sub-Saharan regions of Africa. We compare growth between cytotypes and test whether polyploid seedlings grow better than diploids. Our results show that polyploids coexist with diploids in highly variable proportions among populations in Senegal. Acacia senegal genotypes were predominantly diploid and tetraploid, but triploid, pentaploid, hexaploid, and octaploid forms were also found. We find that polyploids show faster growth than diploids under our test conditions: in an 18 years old field trial, polyploid superiority was estimated to be 17% in trunk diameter and 9% in height while in a growth chamber experiment, polyploids grew 28% taller, but only after being exposed to drought stress. The results suggest that polyploid A. senegal can have an adaptive advantage in some regions of Africa. PMID:27379120

  16. Politics, Gender and Youth Citizenship in Senegal: Youth Policing of Dissent and Diversity

    ERIC Educational Resources Information Center

    Crossouard, Barbara; Dunne, Máiréad

    2015-01-01

    This paper reports on empirical research on youth as active citizens in Senegal with specific reference to their education and their sexual and reproductive health rights. In a context of postcoloniality which claims to have privileged secular, republican understandings of the constitution, the authors seek to illuminate how youth activists…

  17. Scaling up Sexuality Education in Senegal: Integrating Family Life Education into the National Curriculum

    ERIC Educational Resources Information Center

    Chau, Katie; Traoré Seck, Aminata; Chandra-Mouli, Venkatraman; Svanemyr, Joar

    2016-01-01

    In Senegal, school-based sexuality education has evolved over 20 years from family life education (FLE) pilot projects into cross-curricular subjects located within the national curriculum of primary and secondary schools. We conducted a literature review and semi-structured interviews to gather information regarding the scale and nature of FLE…

  18. Polyploidy can Confer Superiority to West African Acacia senegal (L.) Willd. Trees.

    PubMed

    Diallo, Adja M; Nielsen, Lene R; Kjær, Erik D; Petersen, Karen K; Ræbild, Anders

    2016-01-01

    Polyploidy is a common phenomenon in the evolution of angiosperms. It has been suggested that polyploids manage harsh environments better than their diploid relatives but empirical data supporting this hypothesis are scarce, especially for trees. Using microsatellite markers and flow cytometry, we examine the frequency of polyploids and diploids in a progeny trial testing four different populations of Acacia senegal, a species native to sub-Saharan regions of Africa. We compare growth between cytotypes and test whether polyploid seedlings grow better than diploids. Our results show that polyploids coexist with diploids in highly variable proportions among populations in Senegal. Acacia senegal genotypes were predominantly diploid and tetraploid, but triploid, pentaploid, hexaploid, and octaploid forms were also found. We find that polyploids show faster growth than diploids under our test conditions: in an 18 years old field trial, polyploid superiority was estimated to be 17% in trunk diameter and 9% in height while in a growth chamber experiment, polyploids grew 28% taller, but only after being exposed to drought stress. The results suggest that polyploid A. senegal can have an adaptive advantage in some regions of Africa. PMID:27379120

  19. Peace Corps Rural Energy Survey: Senegal. Training for Development Series. Training Manual No. T-27.

    ERIC Educational Resources Information Center

    Peace Corps, Washington, DC. Information Collection and Exchange Div.

    This survey was undertaken by the Peace Corps to assist Senegal in identifying energy needs in rural areas and in implementing alternative, renewable energy projects at the community level. This book describes the sample, energy use, energy needs, and resources. Fifteen villages of fewer than 5,000 people were selected for data collection. The…

  20. Language Use along the Urban Street in Senegal: Perspectives from Proprietors of Commercial Signs

    ERIC Educational Resources Information Center

    Shiohata, Mariko

    2012-01-01

    Senegal adopted French as the country's sole official language at the time of independence in 1960, since when the language has been used in administration and other formal domains. Similarly, French is employed throughout the formal education system as the language of instruction. Since the 1990s, however, government has mounted an ambitious…

  1. Linkages between observed, modeled Saharan dust loading and meningitis in Senegal during 2012 and 2013.

    PubMed

    Diokhane, Aminata Mbow; Jenkins, Gregory S; Manga, Noel; Drame, Mamadou S; Mbodji, Boubacar

    2016-04-01

    The Sahara desert transports large quantities of dust over the Sahelian region during the Northern Hemisphere winter and spring seasons (December-April). In episodic events, high dust concentrations are found at the surface, negatively impacting respiratory health. Bacterial meningitis in particular is known to affect populations that live in the Sahelian zones, which is otherwise known as the meningitis belt. During the winter and spring of 2012, suspected meningitis cases (SMCs) were with three times higher than in 2013. We show higher surface particular matter concentrations at Dakar, Senegal and elevated atmospheric dust loading in Senegal for the period of 1 January-31 May during 2012 relative to 2013. We analyze simulated particulate matter over Senegal from the Weather Research and Forecasting (WRF) model during 2012 and 2013. The results show higher simulated dust concentrations during the winter season of 2012 for Senegal. The WRF model correctly captures the large dust events from 1 January-31 March but has shown less skill during April and May for simulated dust concentrations. The results also show that the boundary conditions are the key feature for correctly simulating large dust events and initial conditions are less important. PMID:26296434

  2. Science and Religion on the Blackboard: Exploring Schoolmasters' Beliefs and Practices in Senegal

    ERIC Educational Resources Information Center

    Croché, Sarah

    2015-01-01

    This article treats the various forms of adjustment between scientific and religious discourses at school. It aims to analyse the beliefs and practices of schoolmasters and to explore how the oppositions between the "dominant" discourses of Western science and those of religion are addressed in secondary education in Senegal. The…

  3. Linkages between observed, modeled Saharan dust loading and meningitis in Senegal during 2012 and 2013

    NASA Astrophysics Data System (ADS)

    Diokhane, Aminata Mbow; Jenkins, Gregory S.; Manga, Noel; Drame, Mamadou S.; Mbodji, Boubacar

    2016-04-01

    The Sahara desert transports large quantities of dust over the Sahelian region during the Northern Hemisphere winter and spring seasons (December-April). In episodic events, high dust concentrations are found at the surface, negatively impacting respiratory health. Bacterial meningitis in particular is known to affect populations that live in the Sahelian zones, which is otherwise known as the meningitis belt. During the winter and spring of 2012, suspected meningitis cases (SMCs) were with three times higher than in 2013. We show higher surface particular matter concentrations at Dakar, Senegal and elevated atmospheric dust loading in Senegal for the period of 1 January-31 May during 2012 relative to 2013. We analyze simulated particulate matter over Senegal from the Weather Research and Forecasting (WRF) model during 2012 and 2013. The results show higher simulated dust concentrations during the winter season of 2012 for Senegal. The WRF model correctly captures the large dust events from 1 January-31 March but has shown less skill during April and May for simulated dust concentrations. The results also show that the boundary conditions are the key feature for correctly simulating large dust events and initial conditions are less important.

  4. Assessment of the undiscovered oil and gas of the Senegal province, Mauritania, Senegal, the Gambia, and Guinea-Bissau, northwest Africa

    USGS Publications Warehouse

    Brownfield, Michael E.; Charpentier, Ronald R.

    2003-01-01

    Undiscovered, conventional oil and gas resources were assessed in the Senegal Province as part of the U.S. Geological Survey World Petroleum Assessment 2000 (U.S. Geological Survey World Energy Assessment Team, 2000). Although several total petroleum systems may exist in the province, only one composite total petroleum system, the Cretaceous-Tertiary Composite Total Petroleum System, was defined with one assessment unit, the Coastal Plain and Offshore Assessment Unit, having sufficient data to allow quantitative assessment. The primary source rocks for the Cretaceous-Tertiary Composite Total Petroleum System are the Cenomanian-Turonian marine shales. The Turonian shales can be as much as 150 meters thick and contain Type II organic carbon ranging from 3 to 10 weight percent. In the Senegal Province, source rocks are mature even when situated at depths relatively shallow for continental passive margin basins. Reservoir rocks consist of Upper Cretaceous sandstones and lower Tertiary clastic and carbonate rocks. The Lower Cretaceous platform carbonate rocks (sealed by Cenomanian shales) have porosities ranging from 10 to 23 percent. Oligocene carbonate rock reservoirs exist, such as the Dome Flore field, which contains as much as 1 billion barrels of heavy oil (10? API, 1.6 percent sulfur) in place. The traps are a combination of structural closures and stratigraphic pinch-outs. Hydrocarbon production in the Senegal Province to date has been limited to several small oil and gas fields around Cape Verde (also known as the Dakar Peninsula) from Upper Cretaceous sandstone reservoirs bounded by normal faults, of which three fields (two gas and one oil) exceed the minimum size assessed in this study (1 MMBO; 6 BCFG). Discovered known oil resources in the Senegal Province are 10 MMBO, with known gas resources of 49 BCFG (Petroconsultants, 1996). This study estimates that 10 percent of the total number of potential oil and gas fields (both discovered and undiscovered) of at

  5. Transboundary water resources management and livelihoods: interactions in the Senegal river

    NASA Astrophysics Data System (ADS)

    Bruckmann, Laurent; Beltrando, Gérard

    2016-04-01

    In Sub-Saharan Africa, 90 % of wetlands provide ecosystem services to societies, especially for agriculture and fishing. However, tropical rivers are increasingly regulated to provide hydroelectricity and irrigated agriculture. Modifications of flows create new hydrological conditions that affect floodplains ecology and peoples' livelihoods. In the Senegal river valley, large dams were built during the 1980's to secure water resources after a decade of water scarcity in the 1970's: Manantali in the upper basin with a reservoir of 12km3 and Diama close to estuary to avoid saltwater intrusion during dry season. Senegal river water resources are known under the supervision of Senegal River Basin Development Organization (OMVS), which defines water allocation between different goals (electricity, irrigation, traditional activities). This study, based on the concept of socio-hydrology, analyses socio-ecological changes following thirty years of dam management. The work enlightens adaptation mechanisms of livelihoods from people living along the river floodplain and feedback on water ressources. The study uses a mixed method approach, combining hydrological analyses, literature review and data collection from surveys on stakeholders and key informants level in the middle Senegal valley. Our results suggest that in all the Senegal river valley, socio-ecological changes are driven by new hydrological conditions. If dam management benefit for peoples with electrification and development of an irrigated agriculture, it has also emphasized the floodplain degradation. Flooded area has decline and are more irregular, causing an erosion of floodplain supporting services (traditional activities as fishing, grazing and flood-recession agriculture). These conditions reduce peoples' livelihood possibilities and irrigation is the only regular activity. As a feedback, irrigated agriculture increases withdrawals in the river and, recently, in aquifers posing a new uncertainty on water

  6. Ecological impact of historical and future land-use patterns in Senegal

    USGS Publications Warehouse

    Parton, W.; Tappan, G. Gray; Ojima, D.; Tschakert, P.

    2004-01-01

    The CENTURY model was used to simulate changes in total system carbon resulting from land-use history (1850–2000), and impacts of climatic changes and improved land-use management practices in Senegal. Results show that 0.477 Gtons of carbon have been lost from 1850 to 2000. Improved management practices have the potential of increasing carbon levels by 0.116 Gtons from 2000 to 2100. Potential to store carbon exists for improved forest management and agriculture practices in southern Senegal. Potential climatic changes decrease plant production (30 percent), total system carbon (14 percent), and the potential to store carbon from improved management practices (31 percent).

  7. Tropheryma whipplei as a Cause of Epidemic Fever, Senegal, 2010-2012.

    PubMed

    Bassene, Hubert; Mediannikov, Oleg; Socolovschi, Cristina; Ratmanov, Pavel; Keita, Alpha K; Sokhna, Cheikh; Raoult, Didier; Fenollar, Florence

    2016-07-01

    The bacterium Tropheryma whipplei, which causes Whipple disease in humans, is commonly detected in the feces of persons in Africa. It is also associated with acute infections. We investigated the role of T. whipplei in febrile patients from 2 rural villages in Senegal. During June 2010-March 2012, we collected whole-blood finger-prick samples from 786 febrile and 385 healthy villagers. T. whipplei was detected in blood specimens from 36 (4.6%) of the 786 febrile patients and in 1 (0.25%) of the 385 apparently healthy persons. Of the 37 T. whipplei cases, 26 (70.2%) were detected in August 2010. Familial cases and a potential new genotype were observed. The patients' symptoms were mainly headache (68.9%) and cough (36.1%). Our findings suggest that T. whipplei is a cause of epidemic fever in Senegal. PMID:27314980

  8. Tropheryma whipplei as a Cause of Epidemic Fever, Senegal, 2010–2012

    PubMed Central

    Bassene, Hubert; Mediannikov, Oleg; Socolovschi, Cristina; Ratmanov, Pavel; Keita, Alpha K.; Sokhna, Cheikh; Raoult, Didier

    2016-01-01

    The bacterium Tropheryma whipplei, which causes Whipple disease in humans, is commonly detected in the feces of persons in Africa. It is also associated with acute infections. We investigated the role of T. whipplei in febrile patients from 2 rural villages in Senegal. During June 2010–March 2012, we collected whole-blood finger-prick samples from 786 febrile and 385 healthy villagers. T. whipplei was detected in blood specimens from 36 (4.6%) of the 786 febrile patients and in 1 (0.25%) of the 385 apparently healthy persons. Of the 37 T. whipplei cases, 26 (70.2%) were detected in August 2010. Familial cases and a potential new genotype were observed. The patients’ symptoms were mainly headache (68.9%) and cough (36.1%). Our findings suggest that T. whipplei is a cause of epidemic fever in Senegal. PMID:27314980

  9. Coastal Observations of Weather Features in Senegal during the AMMA SOP-3 Period

    NASA Technical Reports Server (NTRS)

    Jenkins, G.; Kucera, P.; Joseph, E.; Fuentes, J.; Gaye, A.; Gerlach, J.; Roux, F.; Viltard, N.; Papazzoni, M.; Protat, A.; Bouniol, D.; Reynolds, A.; Arnault, J.; Badiane, D.; Kebe, F.; Camara, M.; Sall, S.

    2009-01-01

    During 15 August through 30 September 2006, ground and aircraft measurements were obtained from a multi-national group of students and scientists in Senegal. Key measurements were aimed at investigating and understanding precipitation processes, thermodynamic and dynamic environmental conditions, cloud, aerosol and microphysical processes and spaceborne sensors (TRMM, CloudSat/Calipso) validation. Ground and aircraft instruments include: ground based polarimetric radar, disdrometer measurements, a course and a high-density rain gauge network, surface chemical measurements, a 10 m flux tower, broadband IR, solar and microwave measurements, rawinsonde and radiosonde measurements, FA-20 dropsonde, in situ microphysics and cloud radar measurements. Highlights during SOP3 include ground and aircraft measurements of squall lines, African Easterly Waves (AEWs), Saharan Air Layer advances into Senegal, and aircraft measurements of AEWs -- including the perturbation that became Hurricane Isaac.

  10. Mbaraan and the shifting political economy of sex in urban Senegal.

    PubMed

    Foley, Ellen E; Drame, Fatou Maria

    2013-01-01

    This paper examines transactional sex in Dakar as a window into broader processes of social and economic change in urban Senegal. Patterns of heterosexual behaviour in Senegal's capital (late and increasing age at first marriage for women, a relatively high divorce rate and a rise in transactional sex) reflect a confluence of socioeconomic forces that curtail some forms of heterosexual union and facilitate others. Our analysis focuses on the rise of mbaraan, a practice in which single, married and divorced women have multiple male partners. We argue that while mbaraan is in part an expression of women's agency and a transgression of dominant gender norms, it also reflects women's social and economic subordination and their inability to achieve self-sufficiency independent of men's financial support. We suggest that this urban phenomenon is the outcome of contradictory opportunities and constraints that women face as they grapple with material insecurity and marital disappointments. PMID:23181265

  11. The epidemiology of human and animal schistosomiasis in the Senegal River Basin.

    PubMed

    Vercruysse, J; Southgate, V R; Rollinson, D

    1985-09-01

    The results of four field surveys in Senegal are reported. 1. A snail survey in various parts of the Senegal River Basin, including the Senegal River, temporary rain-fed pools, swamps, irrigation canals and drains, ricefields and Lac de Guier was carried out. Three species of snails were commonly found: Bulinus guernei was the most common, occurring in permanent habitats, Bulinus senegalensis occurring in laterite pools in the eastern part of the Middle Valley, and also in the ricefields of Guédé Chantier and Lampsar; B. forskalii was found in small numbers in Lac de Guier and Richard Toll. Three B. guernei were found to be naturally infected with S. bovis. Neither B. jousseaumei, B. globosus nor B. umbilicatus were found in our surveys. 2. A survey for urinary schistosomiasis was carried out in 100 villages (walo, near the Senegal River) and 11 villages (diéré, away from the river) by delivering questionnaires in schools and by direct examinations of haematuria samples. The prevalence of haematuria varied between 0 and 33%. Generally, walos showed low rates of haematuria with the exception of Lampsar and Guédé Chantier, and diérés showed higher rates of haematuria. 3. Examination of 400 cattle at the abattoir St. Louis, revealed a prevalence of 80% of schistosome infection. Two species were present, S. bovis and less commonly S. curassoni. Sometimes high worm burdens were seen, but lesions appeared to be minimal because of high ratio of male to female worms. 4. Examinations of 5722 sheep and 1752 goats in the abattoir, Dakar revealed an overall prevalence of 2.1%. Of the infected animals, 97.3% were infected with S. curassoni and 2.7% with S. curasonni and S. bovis. Laboratory snail infection experiments showed that S. curassoni is marginally compatible with B. senegalensis, but incompatible with B. guernei. PMID:2865881

  12. Estimates of the Incidence of Induced Abortion And Consequences of Unsafe Abortion in Senegal

    PubMed Central

    Sedgh, Gilda; Sylla, Amadou Hassane; Philbin, Jesse; Keogh, Sarah; Ndiaye, Salif

    2015-01-01

    CONTEXT Abortion is highly restricted by law in Senegal. Although women seek care for abortion complications, no national estimate of abortion incidence exists. METHODS Data on postabortion care and abortion in Senegal were collected in 2013 using surveys of a nationally representative sample of 168 health facilities that provide postabortion care and of 110 professionals knowledgeable about abortion service provision. Indirect estimation techniques were applied to the data to estimate the incidence of induced abortion in the country. Abortion rates and ratios were calculated for the nation and separately for the Dakar region and the rest of the country. The distribution of pregnancies by planning status and by outcome was estimated. RESULTS In 2012, an estimated 51,500 induced abortions were performed in Senegal, and 16,700 (32%) resulted in complications that were treated at health facilities. The estimated abortion rate was 17 per 1,000 women aged 15–44 and the abortion ratio was 10 per 100 live births. The rate was higher in Dakar (21 per 1,000) than in the rest of the country (16 per 1,000). Poor women were far more likely to experience abortion complications, and less likely to receive treatment for complications, than nonpoor women. About 31% of pregnancies were unintended, and 24% of unintended pregnancies (8% of all pregnancies) ended in abortion. CONCLUSIONS Unsafe abortion exacts a heavy toll on women in Senegal. Reducing the barriers to effective contraceptive use and ensuring access to postabortion care without the risk of legal consequences may reduce the incidence of and complications from unsafe abortion. PMID:25856233

  13. From past to future agricultural expertise in Africa: Jola women of Senegal expand market-gardening

    PubMed Central

    Linares, Olga F.

    2009-01-01

    Jola women farmers in the Casamance region of southern Senegal use their “traditional” knowledge and farming skills to shift crop repertoires and techniques so as to embark on market-gardening, thus innovating in response to new needs and perceived opportunities. The argument is relevant to present-day concerns about regional food systems and the role of women in securing an income and providing extra food for the family. PMID:19965372

  14. Politics, gender and youth citizenship in Senegal: Youth policing of dissent and diversity

    NASA Astrophysics Data System (ADS)

    Crossouard, Barbara; Dunne, Máiréad

    2015-02-01

    This paper reports on empirical research on youth as active citizens in Senegal with specific reference to their education and their sexual and reproductive health rights. In a context of postcoloniality which claims to have privileged secular, republican understandings of the constitution, the authors seek to illuminate how youth activists sustain patriarchal, metropolitan views of citizenship and reinforce ethnic and locational (urban/rural) hierarchies. Their analysis is based on a case study of active youth citizenship, as reflected in youth engagement in the recent presidential elections in Senegal. This included involvement in youth protests against pre-election constitutional abuse and in a project monitoring the subsequent elections using digital technologies. The authors compare how youth activists enacted different notions of citizenship, in some instances involving a vigorous defence of Senegal's democratic constitution, while in others dismissing this as being irrelevant to youth concerns. Here the authors make an analytic distinction between youth engagement in politics, seen as the public sphere of constitutional democracy, and the political, which they relate to the inherently conflictual and agonistic processes through which (youth) identities are policed, in ways which may legitimate or marginalise. Despite the frequent construction of youth as being agents of change, this analysis shows how potentially productive and open spaces for active citizenship were drawn towards conformity and the reproduction of existing hegemonies, in particular through patriarchal gender relations and sexual norms within which female youth remained particularly vulnerable.

  15. [Excision: the new prohibition that divides the society. Press review: Senegal].

    PubMed

    1999-12-01

    Approximately 700,000 women in Senegal have suffered female genital mutilation (FGM). Now, following a vote upon legislation banning FGM, public opinion in the country over the practice is more divided than ever. The practitioners of FGM are not taking the law seriously, while politicians hesitate to openly condemn the practice, which still occurs widely in rural zones. Most of the 140 parliamentarians do not believe that laws alone can successfully end FGM in Senegal. Some deputies and feminists believe that several years of sensitization on the issue will be needed to effectively reduce the frequency with which FGM is practiced. Only optimists believe FGM will disappear on its own. The debate threatens to resurface in some areas during the year 2000 presidential election. One deputy from the governing party, originally from southern Senegal, states that he dares not tell his constituency that the president himself created the anti-FGM legislation, especially when locally elected leaders finance villages¿ FGM-related celebrations. According to a scholar of the Koran, FGM is an Islamic practice, but it is not taught in the Koran. FGM is therefore a cultural practice borne from individual choice. In Kolda, 650 km south of Dakar, the practitioners of such mutilation argue that they would rather be imprisoned than abandon the practice they consider to be an immutable component of their cultural history. PMID:12296198

  16. Schistosomiasis Sustained Control Program in Ethnic Groups Around Ninefescha (Eastern Senegal).

    PubMed

    N'Diaye, Monique; Dioukhane, Elhadji M; Ndao, Babacar; Diedhiou, Kemo; Diawara, Lamine; Talla, Idrissa; Vernet, Charlotte; Bessin, François; Barbier, Dominique; Dewavrin, Patrick; Klotz, Francis; Georges, Pierre

    2016-09-01

    Schistosomiasis is the second most significant parasitic disease in children in several African countries. For this purpose, the "Programme National de Lutte contre les Bilharzioses" (PNLB) was developed in partnership with the World Health Organization (WHO) to control this disease in Senegal. However, geographic isolation of Bedik ethnic groups challenged implementation of the key elements of the schistosomiasis program in eastern Senegal, and therefore, a hospital was established in Ninefescha to improve access to health care as well as laboratory support for this population. The program we have implemented from 2008 in partnership with the PNLB/WHO involved campaigns to 1) evaluate schistosomiasis prevalence in children of 53 villages around Ninefescha hospital, 2) perform a mass drug administration following the protocol established by the PNLB in school-aged children, 3) monitor annual prevalence, 4) implement health education campaigns, and 5) oversee the building of latrines. This campaign led to a drop in schistosomiasis prevalence but highlighted that sustainable schistosomiasis control by praziquantel treatment, awareness of the use of latrines, and inhabitants' voluntary commitment to the program are crucial to improve Schistosoma elimination. Moreover, this study revealed that preschool-aged children, for whom praziquantel was not recommended until 2014 in Senegal, constituted a significant reservoir for the parasite. PMID:27430549

  17. Invasion genetics of the introduced black rat (Rattus rattus) in Senegal, West Africa.

    PubMed

    Konečný, Adam; Estoup, Arnaud; Duplantier, Jean-Marc; Bryja, Josef; Bâ, Khalilou; Galan, Maxime; Tatard, Caroline; Cosson, Jean-Francois

    2013-01-01

    An understanding of the evolutionary history and dynamics of invasive species is required for the construction of predictive models of future spread and the design of biological management measures. The black rat (Rattus rattus) is a major vertebrate invader with a worldwide distribution. Despite the severe ecological, economic and health impacts of this species, its evolutionary history has been little studied. We carried out extensive specimen sampling in Senegal, West Africa, and used microsatellite markers to describe the pattern and processes of invasion in this large continental area. The genetic data obtained were combined with historical knowledge concerning the presence of this species in Senegal. Data were analysed by a combination of Bayesian clustering and approximate Bayesian computation methods. The invasion pathways closely paralleled the history of human trade routes in Senegal. In several places, we detected the occurrence of multiple introductions from genetically different sources. Long-distance migration between towns and villages was also observed. Our findings suggest that genetic bottlenecks and admixture have played a major role in shaping the genetics of invasive black rats. These two processes may generate genetic novelty and favour rapid evolution along the invasion pathways. PMID:23206272

  18. Estimation of population iodine intake from iodized salt consumed through bouillon seasoning in Senegal.

    PubMed

    Spohrer, Rebecca; Knowles, Jacqueline; Jallier, Vincent; Ndiaye, Banda; Indorf, Caroline; Guinot, Philippe; Kupka, Roland

    2015-11-01

    Universal salt iodization (USI) is the main global strategy to eliminate iodine deficiency. Regulation of USI programs often omits salt used in processed foods, despite their increasing contribution to salt intake. In West Africa, bouillon seasoning is a widely consumed source of salt and is therefore relevant to USI effectiveness. To develop program guidance around iodine in bouillon, iodine retention in 13 bouillon brands commercially available in Senegal was measured over 6 months. Iodine content was measured in broth using various water volumes and cooking times, as well as in rice cooked in the broth. Average iodine loss in bouillon over 6 months in 95% humidity at 40-40.5 °C was 4.5% (13.6% for cubes and 0.8% for powder sachets). Iodine was retained in broth with cooking times of up to an hour and in rice cooked in broth. Modeling of contribution to iodine intake revealed that bouillon is an important source of dietary iodine in Senegal. Results may inform salt iodization standards and regulation in Senegal and countries with similar bouillon consumption levels. PMID:26767583

  19. [Epidemiology of human schistosomiasis in Mauritania. The right bank of the Senegal River as model].

    PubMed

    Ouldabdallahi, M; Ouldbezeid, M; Diop, C; Dem, E; Lassana, K

    2010-12-01

    A study was performed to determine the transmission and prevalence of human schistosomiasis in the Mauritanian side of the Senegal River basin. Parasitological investigations by Kato-Katz and urine filtration conducted on 1,259 school children indicated a mean prevalence of S. haematobium--29.0%, 25.9% and 34.3%, respectively, in the children of the lower, middle and high valley. Only the school children of the lower delta valley were infected by S. mansoni with a mean prevalence rate of 21.5%. The malacological investigations carried out in the water points of each visited village highlighted the presence of B. pfeifferi, B. senegalensis, B. globosus, B. umbilicatus, B. truncatus and B. forskalii. The last three species are announced for the first time in the Mauritanian side of the Senegal River. The laboratory snail infection experiments indicate that B. senegalensis and B. globosus are the most important intermediate hosts for S. haematobium in the Mauritanian side of the Senegal River basin. However, an incompatibility between the oasis strains of S. haematobium and the snails of the lower valley was noted. In the middle valley and high valley, the infection of the school children takes place during the rainy season, because of the creation of the temporary water points, in the lower valley; the transmission seems to be continuous. PMID:20686878

  20. Ultra-relativistic Au+Au and d+Au collisions:

    NASA Astrophysics Data System (ADS)

    Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Chai, Z.; Decowski, M. P.; García, E.; Gburek, T.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Hauer, M.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Seals, H.; Sedykh, I.; Skulski, W.; Smith, C. E.; Stankiewicz, M. A.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Tang, J.-L.; Tonjes, M. B.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Vaurynovich, S. S.; Verdier, R.; Veres, G. I.; Wenger, E.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.

    In this talk I will review PHOBOS data on charged particle multiplicities, obtained in Au+Au and d+Au collisions at RHIC. The general features of the Au+Au pseudorapidity distributions results will be discussed and compared to those of /line{p}p collisions. The total charged particle multiplicity, scaled by the number of participant pairs, is observed to be about 40% higher in Au+Au collisions than in /line{p}p and d+Au systems, but, surprisingly at the same level of e+e- collisions. Limiting fragmentation scaling is seen to be obeyed in Au+Au collisions.

  1. [A comparative presentation of the population policies of Burkina Faso, Mali and Senegal].

    PubMed

    Dabo, K

    1992-07-01

    Population policies are currently at the center of debates about demography and development, and are a preoccupation of most governments, international organizations, and research institutions working in the areas of population, development, and human resources. Between 1988-93, 4 Sahel countries adopted populations policies. this article compares the policies of Senegal, Mali, and Burkina Faso. The 3 policy documents have similar structures, with preambles recalling the international agreements concerning population and development entered into by their governments. A chapter on population and development describes the demo-economic problem in each country at regional, sectorial, and global levels. After the analysis of demo-economic problems, each of the 3 has a chapter presenting the population policy. Each presentation covers the foundations and basic principles of the policy, its objectives, the strategies to be pursued, and the organizational structure. Development of each policy was technically supervised by the Planning Ministry in collaboration with the national population councils. In general terms, the 3 countries recognize in their basic principles that the population is the primary source of wealth of a nation. Each country states its desire to translate the recommendations of different African and world population conferences into concrete acts. The principles avow respect for fundamental human rights including the right to informed decision making by couples on number and spacing of children. The principles also recognize the need for an integrated approach to population and development. The ultimate objective of the population policies is improvement in the standard and quality of life. The number of general objectives outlined in the policies varied from 7 in Senegal to 13 in Burkina Faso. Senegal was the only country of the 3 to specify reduction of the fertility rate and the growth rate as an objective. Senegal and Burkina Faso included

  2. Breaking Through: TOSTAN's Non-Formal Basic Education Programme in National Languages in Senegal. Education for All: Making It Work. Innovation Series.

    ERIC Educational Resources Information Center

    Guttman, Cynthia

    Since 1988, thousands of rural villagers across Senegal have participated in a basic education program called TOSTAN, which means "breakthrough" in Wolof, the majority language. Supported by UNICEF and implemented in the six national languages of Senegal, TOSTAN goes beyond traditional literacy programs to link literacy learning with life skills…

  3. Genetic and Genomic Diversity Studies of Acacia Symbionts in Senegal Reveal New Species of Mesorhizobium with a Putative Geographical Pattern

    PubMed Central

    Diouf, Fatou; Diouf, Diegane; Klonowska, Agnieszka; Le Queré, Antoine; Bakhoum, Niokhor; Fall, Dioumacor; Neyra, Marc; Parrinello, Hugues; Diouf, Mayecor; Ndoye, Ibrahima; Moulin, Lionel

    2015-01-01

    Acacia senegal (L) Willd. and Acacia seyal Del. are highly nitrogen-fixing and moderately salt tolerant species. In this study we focused on the genetic and genomic diversity of Acacia mesorhizobia symbionts from diverse origins in Senegal and investigated possible correlations between the genetic diversity of the strains, their soil of origin, and their tolerance to salinity. We first performed a multi-locus sequence analysis on five markers gene fragments on a collection of 47 mesorhizobia strains of A. senegal and A. seyal from 8 localities. Most of the strains (60%) clustered with the M. plurifarium type strain ORS 1032T, while the others form four new clades (MSP1 to MSP4). We sequenced and assembled seven draft genomes: four in the M. plurifarium clade (ORS3356, ORS3365, STM8773 and ORS1032T), one in MSP1 (STM8789), MSP2 (ORS3359) and MSP3 (ORS3324). The average nucleotide identities between these genomes together with the MLSA analysis reveal three new species of Mesorhizobium. A great variability of salt tolerance was found among the strains with a lack of correlation between the genetic diversity of mesorhizobia, their salt tolerance and the soils samples characteristics. A putative geographical pattern of A. senegal symbionts between the dryland north part and the center of Senegal was found, reflecting adaptations to specific local conditions such as the water regime. However, the presence of salt does not seem to be an important structuring factor of Mesorhizobium species. PMID:25658650

  4. Collective flow in Au + Au collisions

    SciTech Connect

    Ritter, H.G.; EOS Collaboration

    1994-05-01

    Based on a preliminary sample of Au + Au collisions in the EOS time projection chamber at the Bevalac, we study sideward flow as a function of bombarding energy between 0.25A GeV and 1.2A GeV. We focus on the increase in in-plane transverse momentum per nucleon with fragment mass. We also find event shapes to be close to spherical in the most central collisions, independent of bombarding energy and fragment mass up to {sup 4}He.

  5. Glycemic Control in a Clinic-Based Sample of Diabetics in M'Bour Senegal.

    PubMed

    BeLue, Rhonda; Ndiaye, Khadidiatou; NDao, Fatou; Ba, Fatou Niass Niang; Diaw, Mor

    2016-04-01

    Background Sub-Saharan Africa (SSA) including Senegal is faced with a significant and increasing burden of type 2 diabetes. However, little information is available about diabetes management among Senegalese diabetics.Purpose The current study aims to describe the level of glycemic control among a convenience sample of diabetics who receive care at the M'Bour Hospital in M'Bour, Senegal.Methods A total of 106 type 2 diabetic patients were recruited at the hospital complex of M'Bour, Senegal. Linear regression was employed to assess the relationship between clinical and sociodemographic factors and Hba1c.Results Only 24.8% of the sample had glycemic control, according to an Hba1c test. Participants who were diagnosed earlier were less likely to have diabetes control (mean = 7.8 years) compared with those who were diagnosed more recently (mean = 6.5 years);p< .05.Conclusions We found that glycemic control in our sample was suboptimal. Length of time with diabetes was one of the key factors related to glycemic control. Length of time with diabetes is negatively associated with glycemic control. Early diagnosis and early glycemic control are essential to long-term glycemic control screening, and early detection for diabetes is uncommon given the general lack of health insurance and most people paying out of pocket for medical care. In the absence of universal health insurance, public health programs that provide blood sugar screenings for high-risk individuals would provide preliminary indication of abnormal glucose; however, subsequent diagnostic testing and follow-up may still be cost prohibitive. PMID:27037142

  6. Reconstructing Colonization Dynamics of the Human Parasite Schistosoma mansoni following Anthropogenic Environmental Changes in Northwest Senegal

    PubMed Central

    Van den Broeck, Frederik; Maes, Gregory E.; Larmuseau, Maarten H. D.; Rollinson, David; Sy, Ibrahima; Faye, Djibril; Volckaert, Filip A. M.; Polman, Katja; Huyse, Tine

    2015-01-01

    Background Anthropogenic environmental changes may lead to ecosystem destabilization and the unintentional colonization of new habitats by parasite populations. A remarkable example is the outbreak of intestinal schistosomiasis in Northwest Senegal following the construction of two dams in the ‘80s. While many studies have investigated the epidemiological, immunological and geographical patterns of Schistosoma mansoni infections in this region, little is known about its colonization history. Methodology/Principal Findings Parasites were collected at several time points after the disease outbreak and genotyped using a 420 bp fragment of the mitochondrial cytochrome c oxidase subunit 1 gene (cox1) and nine nuclear DNA microsatellite markers. Phylogeographic and population genetic analyses revealed the presence of (i) many genetically different haplotypes at the non-recombining mitochondrial marker and (ii) one homogenous S. mansoni genetic group at the recombining microsatellite markers. These results suggest that the S. mansoni population in Northwest Senegal was triggered by intraspecific hybridization (i.e. admixture) between parasites that were introduced from different regions. This would comply with the extensive immigration of infected seasonal agricultural workers from neighboring regions in Senegal, Mauritania and Mali. The spatial and temporal stability of the established S. mansoni population suggests a swift local adaptation of the parasite to the local intermediate snail host Biomphalaria pfeifferi at the onset of the epidemic. Conclusions/Significance Our results show that S. mansoni parasites are very successful in colonizing new areas without significant loss of genetic diversity. Maintaining high levels of diversity guarantees the adaptive potential of these parasites to cope with selective pressures such as drug treatment, which might complicate efforts to control the disease. PMID:26275049

  7. Early Infant Male Circumcision in Cameroon and Senegal: Demand, Service Provision, and Cultural Context

    PubMed Central

    Kenu, Ernest; Sint, Tin Tin; Kamenga, Claude; Ekpini, Rene

    2016-01-01

    ABSTRACT Background: Male circumcision is almost universal in North and West Africa, and practiced for various reasons. Yet there is little documentation on service delivery, clinical procedures, policies, and programmatic strategies. The United Nations Children’s Fund (UNICEF) commissioned country program reviews in 2014 to shed light on the delivery of male circumcision services for infants in Cameroon and Senegal. Methods: We conducted a policy desk review, key informant interviews, and focus group discussions at health centers and in communities. Between December 2014 and January 2015, we conducted 21 key informant interviews (13 with regional and district officers, 5 with national officers, and 3 with UNICEF officials) and 36 focus group discussions (6 with men, 6 with women, 12 with adolescent boys, and 12 with service providers). Some of the men and women were parents of the adolescents who participated in the focus group discussions. In the French-speaking areas, the focus group discussions were conducted in French through an accredited translator, audio recorded, and transcribed into English. Results: All of the facilities we visited in Cameroon and Senegal offer medical male circumcision, with 10 out of 12 performing early infant male circumcision (EIMC) routinely. Neither country has policies, guidelines, or strategies for EIMC. The procedure is done mainly by untrained service providers, with some providers using modern circumcision devices. There are no key messages on EIMC for families; the increasing demand for EIMC is led by the community. Conclusion: Despite the absence of national policies and strategies, EIMC is routinely offered at all levels of the health care system in Cameroon and Senegal, mainly by untrained service providers. Improving circumcision services will require guidelines for EIMC and improvements in training, equipment, supply chains, recordkeeping, and demand creation. PMID:27413080

  8. Preparation and characterization of antibacterial Senegalia (Acacia) senegal/iron-silica bio-nanocomposites

    NASA Astrophysics Data System (ADS)

    Şişmanoğlu, Tuba; Karakuş, Selcan; Birer, Özgür; Soylu, Gülin Selda Pozan; Kolan, Ayşen; Tan, Ezgi; Ürk, Öykü; Akdut, Gizem; Kilislioglu, Ayben

    2015-11-01

    Many studies that research bio-nanocomposites utilize techniques that involve the dispersion of strengthening components like silica, metal and metal oxides through a host biopolymer matrix. The biggest success factor for the bio-nanocomposite is having a smooth integration of organic and inorganic phases. This interattraction between the surfaces of inorganic particles and organic molecules are vital for good dispersion. In this study, a novel biodegradable antibacterial material was developed using gum arabic from Senegalia senegal (stabilizer), silica (structure reinforcer) and zero valent iron particles. Silica particles work to not only strengthen the mechanical properties of the Senegalia senegal but also prevent the accumulation of ZVI nanoparticles due to attraction between hydroxyl groups and FeO. The gum arabic/Fe-SiO2 bio-nanocomposite showed effective antibacterial property against the Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. Using Scanning electron microscopy, homogeneous dispersion and uniform particle size was viewed in the biopolymer. X-ray diffraction studies of iron particles organization in Senegalia senegal also showed that the main portion of iron was crystalline and in the form of FeO and Fe0. X-ray photoelectron spectroscopy was used to evaluate the chemical composition of the surface but no appreciable peak was measured for the iron before Ar etching. These results suggest that the surface of iron nanoparticles consist mainly of a layer of iron oxides in the form of FeO. Thermal gravimetric analysis was used to determine the thermal stability and absorbed moisture content.

  9. Sequestration of carbon in soil organic matter in Senegal: an overview

    USGS Publications Warehouse

    Tieszen, Larry L.; Tappan, G. Gray; Toure, A.

    2004-01-01

    The project focuses on four objectives in specific locations across the agroecological zones of Senegal. These objectives are: use of soil sampling and biogeochemical modeling to quantify the biophysical potential for carbon sequestration and to determine the sensitivity of the carbon stocks to various management and climate scenarios, to evaluate the socio-economic and cultural requirements necessary for successful project implementation directed toward an aggregation of smallholders to sequester around 100,000 t carbon (C), to support capacity building to develop a Carbon Specialist Team, and to initiate extrapolation from site-specific project areas to the Sahel region and the national level.

  10. Mechanical characterization of filler sandcretes with rice husk ash additions. Study applied to Senegal

    SciTech Connect

    Cisse, I.K.; Laquerbe, M.

    2000-01-01

    To capitalize on the local materials of Senegal (agricultural and industrial wastes, residual fines from crushing process, sands from dunes, etc.), rise husk ash and residues of industrial and agricultural wastes have been used as additions in sandcretes. The mechanical resistance of sandcrete blocks obtained when unground ash (and notably the ground ash) is added reveals that there is an increase in performance over the classic mortar blocks. In addition, the use of unground rice husk ash enables production of a lightweight sandcrete with insulating properties, at a reduced cost. The ash pozzolanic reactivity explains the high strengths obtained.

  11. Understanding the drivers of agricultural land use change in south-central Senegal

    USGS Publications Warehouse

    Wood, E. C.; Tappan, G. Gray; Hadj, Amadou

    2004-01-01

    Described is (1) the land use and land cover changes that have taken place in the Department of Velingara, an area of tropical dry woodland in south-central Senegal, (2) the biophysical and socio-economic drivers of those changes with an emphasis on transition to agricultural use, and (3) an assessment of the likelihood of intensification of agriculture in the Department. Results indicate that land devoted to agriculture, either in active cultivation or short-term fallow, is increasing. There is little evidence of agricultural intensification in most of Velingara, with extensification coming largely at the cost of reduction in both upland woodlands and riparian forest.

  12. Impacts of land use and climate change on carbon dynamics in south-central Senegal

    USGS Publications Warehouse

    Liu, Shu-Guang; Kaire, M.; Wood, Eric C.; Diallo, O.; Tieszen, Larry L.

    2004-01-01

    Total carbon stock in vegetation and soils was reduced 37% in south-central Senegal from 1900 to 2000. The decreasing trend will continue during the 21st century unless forest clearing is stopped, selective logging dramatically reduced, and climate change, if any, relatively small. Developing a sustainable fuelwood and charcoal production system could be the most feasible and significant carbon sequestration project in the region. If future climate changes dramatically as some models have predicted, cropland productivity will drop more than 65% around 2100, posing a serious threat to food security and the efficiency of carbon sequestration projects.

  13. Non-formal Education and Education Policy in Ghana and Senegal. Educational Studies and Documents, No. 35.

    ERIC Educational Resources Information Center

    United Nations Educational, Scientific, and Cultural Organization, Paris (France).

    One in a series of studies of lifelong learning, this paper discusses the cultural and educational needs of selected urban and rural communities in Senegal and Ghana, emphasizing grassroots initiative and the community's analysis of its own needs. Information is drawn in part from surveys, public meetings, and interviews in three communities:…

  14. Post-Primary Practical Education/Training in Senegal. Description and Evaluation of the Experiment. Occasional Paper No. 3.

    ERIC Educational Resources Information Center

    United Nations Educational, Scientific, and Cultural Organization, Paris (France).

    The document, written in French, presents an overview of educational programs in Senegal where ten to 17-year-old students are taught practical skills. The monograph is intended for UNESCO staff members and educational advisors as they collaborate with governments in developing nations to improve educational programs. The document is presented in…

  15. Implications of Social Practice Theory for the Development of a Numeracy Programme for the Gusilay People Group in Senegal

    ERIC Educational Resources Information Center

    Gerger, Elisabeth

    2014-01-01

    In this article, I present research on some traditional numeracy practices of the Gusilay people group in Senegal and make recommendations for developing a numeracy programme for women. Based on a strong foundation of traditional knowledge and practices, the programme will aim to meet felt needs of women who are faced with new numeracy related…

  16. An Examination of Early Childhood Teacher Education in Four West African Nations: Ghana, Mali, Senegal, and the Gambia.

    ERIC Educational Resources Information Center

    Pagano, Alicia I.

    This paper examines opportunities and challenges in early childhood teacher education in Ghana, Mali, Senegal, and the Gambia. It reviews socioeconomic and political issues, current and emerging policies for early childhood and primary education, teacher preparation strategies, and examples of successful programs. Information was collected during…

  17. Participatory Research Is the First Step towards Political Action: The Case of Young Female Domestic Servants in Dakar, Senegal.

    ERIC Educational Resources Information Center

    Diaw, Bamba

    1996-01-01

    Studied working conditions of female domestic workers in Dakar, Senegal, using group interviews. Found that most leave rural families for economic reasons. Village solidarity networks help find work, maintain rural norms, and provide support. Few employers provide written contracts, medical insurance, or adequate wages. Heavy work responsibilities…

  18. Developpement Cooperatif: Resultats du project et Recommandations en decoulant: Senegal. (Cooperative Development: Project Recommendations and the Results.)

    ERIC Educational Resources Information Center

    United Nations Development Programme, Geneva (Switzerland).

    The document reports on the activities undertaken and the results achieved in a project intended to develop cooperatives of food producers (including fisheries, farming and fruit growing) in Senegal. Three consultants were requested of and provided by the International Labor Organization, for the United Nations Development Program. Working with…

  19. Urinary schistosomiasis in the Sahelian region of the Senegal River Basin.

    PubMed

    Chaine, J P; Malek, E A

    1983-09-01

    Two dams are projected for the Senegal River, West Africa, for hydroelectric power, anti-salt intrusion and for provision of a dependable supply of freshwater year-round. This study was to ascertain the geographic distribution of schistosomiasis, its snail hosts and the potential transmission sites before the construction of the two dams. No intestinal schistosomiasis was found in the area investigated, the Sahelian region. Villages in the delta, as well as those situated by the Senegal River in the Middle Valley were found free of urinary schistosomiasis. However, the prevalence of the urinary form averaged 10.4% in villages situated in the higher land away from the river. The transmission sites in these villages are rain-fed, laterite pools which harbor the snail host, Bulinus senegalensis. In one pond the latter was found naturally infected with schistosome cercariae, and there are no bovines or ovines in the area at any time. Other bulinid snails found infected with schistosome cercariae were B. guernei and B. jousseaumei; the latter is probably the snail host of Schistosoma haematobium in one small village in the delta, where a low infection rate was reported by other workers. PMID:6649050

  20. Creating political priority for micronutrient deficiencies: a qualitative case study from Senegal

    PubMed Central

    Balarajan, Yarlini

    2014-01-01

    Objectives To examine what factors influence the agenda-setting process and level of political priority afforded to micronutrient deficiencies (MNDs). Design Qualitative case study employing process tracing, informed by primary data collected from semistructured interviews with policymakers. Setting Dakar, Senegal. Results Several facilitating and impeding factors affecting the level of political prioritisation for MNDs were identified. Facilitating factors included multiple stakeholders using aligned framing to collectively advocate for MNDs; availability of indicators to quantify issue severity and raise awareness; and transnational advocacy activities around micronutrients. Impeding factors included lack of awareness among policymakers and civil society about MNDs; issue complexity, with the need for coordinated multisectoral response to deliver a complex package of solutions; lack of resources trapping the issue in a ‘low-priority’ cycle; lack of a policy champion to advocate for the issue and the challenge of demonstrating the effectiveness of interventions to support advocacy efforts. Conclusions This study gives insight into the political prioritisation process for MNDs from the perspective of key stakeholders working at the national level in Senegal. In doing so, the study offers some explanation as to why the issue of MNDs has struggled to gain political attention and make it onto the national policy agenda. Moving forward, greater awareness of the factors affecting agenda setting for MNDs may help to devise political strategies to champion this development issue in countries with high burdens of micronutrient deficiencies. PMID:25107435

  1. Evaluation of land performance in Senegal using multi-temporal NDVI and rainfall series

    USGS Publications Warehouse

    Li, J.; Lewis, J.; Rowland, J.; Tappan, G.; Tieszen, L.L.

    2004-01-01

    Time series of rainfall data and normalized difference vegetation index (NDVI) were used to evaluate land cover performance in Senegal, Africa, for the period 1982-1997, including analysis of woodland/forest, agriculture, savanna, and steppe land cover types. A strong relationship exists between annual rainfall and season-integrated NDVI for all of Senegal (r=0.74 to 0.90). For agriculture, savanna, and steppe areas, high positive correlations portray 'normal' land cover performance in relation to the rainfall/NDVI association. Regions of low correlation might indicate areas impacted by human influence. However, in the woodland/forest area, a negative or low correlation (with high NDVI) may reflect 'normal' land cover performance, due in part to the saturation effect of the rainfall/NDVI association. The analysis identified three areas of poor performance, where degradation has occurred over many years. Use of the 'Standard Error of the Estimate' provided essential information for detecting spatial anomalies associated with land degradation. ?? 2004 Elsevier Ltd. All rights reserved.

  2. [Characteristics of occupational accidents in the building industry and public works in Senegal].

    PubMed

    Mbaye, I; Fall, M C; Sarr, E H; Ouatara, B; Sow, M L

    2001-01-01

    The objectives of this study were to appreciate the magnitude of work accidents in a building construction sector, to specify their type and characteristics. A retrospective study was undergone in a big building construction industry in Senegal. Data were collected from records of accidents reported to the Social Security Administration between 1994--1996. We looked for characteristics of accidents as well as workers involved in accident. 244 accidents were collected in a three years period, i e 81.5/year, 132 work injuries involved temporaryworkers. 55.73% occurred in chantiers, and 1/3 in working room. Moving and handle objects generated most accidents (36,47%). Wounds and contusions were the most frequent lesion (51,62.%). Arms and feets were concerned in 51.63%, and ocular lesions were noticed in 13.94%. These accidents generate an overall number of 3055 days lost. Work injuries in the building construction sector in Senegal are identical to those described in othercountries. Prevention measures requires improvement of working conditions, education of workers and availability of personal protective equipment's. PMID:15773178

  3. [Participation of women in decision-making in Senegal. The numbers that speak].

    PubMed

    Talla, R

    1999-12-01

    The most recent population survey conducted in Senegal in 1988 found that women comprise 52% of the country¿s total population and that rural women make up 75% of the active female population. The female population is very young overall since 58% of women are under 20 years old. However, women¿s numerical advantage is inversely proportional to their level of representation in decision-making situations. Senegal¿s government in power since 1998 has only 5 women among the 31 ministers, and there were only 3 female ministers in the preceding body of government leaders. This numerical underrepresentation of women is also qualitative in nature, with the female ministers holding relatively less powerful governmental positions compared to the men. Only 19 of the 140 deputies elected to the National Assembly in 1998 were women and no woman is president of a parliamentary body. Women have a greater presence at the magisterial and legislative level, but they are less present in the public sector where they comprise only 4% of the 68,000 state agents. Women overwhelmingly hold teacher and secretarial posts, while men dominate local communities. Among the 470 elected, regional councilors elected in November 1998, only 61 are women. Additional statistics and discussion are presented upon the role of women in Senegalese society, as well as upon their capacity to influence important decisions both in the public sector and at home. PMID:12296191

  4. Population structure of newly established Anopheles funestus populations in the Senegal River basin using paracentric chromosomal inversions.

    PubMed

    Dia, Ibrahima; Samb, Badara; Konate, Lassana; Fontenille, Didier

    2010-01-01

    Anopheles funestus is one of the major vectors of malaria in sub-saharan Africa. Because of several cycles of recurrent drought events that have occurred in the sahelian zone, this species had disappeared from this area since the 1970s following a disappearance of its specific breeding sites. Its comeback was, however, recently observed particularly in the Senegal River basin following the implementation of two dams. Because the implementation of hydro-agricultural and irrigation settings are suspected to be involved in the reestablishment of An. funestus populations and that paracentric inversions are involved in the adaptation to various environments, the present study was undertaken in 3 villages of the Senegal River basin (Keur Mbaye, Mbilor and Gankette Balla), (i) to study the chromosomal polymorphism of the newly established An. funestus populations in the Senegal River basin using paracentic inversions from ovarian nurse cells and (ii) their relationship with other populations of this species located in different environmental contexts (Dielmo in sudanian zone, Sankagne and Kouvar in northern sudano-guinean zone and Ngari in southern sudano-guinean zone) in order to know the key factors leading to their reestablishment in this area. Our results showed that the newly established An. funestus populations' exhibit low level of chromosomal polymorphism with two chromosomal inversions (the fixed 2Rs and the polymorphic 3La) out of the 9 paracentric inversions described up to now in An. funestus in Senegal. At population level, no significant deviation from Hardy-Weinberg equilibrium was observed for almost all inversions. Furthermore, significant genetic differentiation was revealed between the populations from the Senegal River basin and those from the sudanian and southern sudano-guinean zones and was not linked to geographical distance. However, the populations from the Senegal River basin were close or slightly differentiated to those from the northern

  5. Situational analysis of infant and young child nutrition policies and programmatic activities in Senegal.

    PubMed

    Wuehler, Sara E; Ly Wane, Coudy Thierno

    2011-04-01

    Progress towards reducing mortality and malnutrition among children <5 years of age has been less than needed to achieve related Millennium Development Goals (MDGs). Therefore, several international agencies joined to 'Reposition children's right to adequate nutrition in the Sahel', starting with an analysis of current activities related to infant and young child nutrition (IYCN). The main objectives of the situational analysis are to compile, analyse and interpret available information on infant and child feeding and the nutrition situation of children <2 years of age in Senegal, as one of the six targeted countries. These findings will be used to assist in identifying inconsistencies and filling gaps in current programming. Between August and December 2008, key informants responsible for conducting IYCN-related activities in Senegal were interviewed, and 157 documents were examined on the following themes: optimal breastfeeding and complementary feeding practices, prevention of micronutrient deficiencies, prevention of mother-to-child transmission of HIV, management of acute malnutrition, food security and hygienic practices. Nearly all of the key IYCN topics were addressed, specifically or generally, in national policy documents. Senegal reported substantial improvements since the 1990s towards reducing infant and young child mortality and underweight, and increasing exclusive breastfeeding among infants <6 months of age (34%). Senegal is one of the few countries in the region that is nearly on track for reaching related MDGs. Notable activities that may have played a role include: (1) vitamin A supplementation was expanded to nearly semi-annual national campaigns starting in 1994; (2) the Ministry of Health partnered with several national and international agencies to scale up child survival activities under the umbrella of the Basic Support for Institutionalizing Child Survival (1994-2006); (3) a national nutrition division was developed to support a national

  6. Case investigation and reactive case detection for malaria elimination in northern Senegal

    PubMed Central

    2013-01-01

    Background Given progress in malaria control in recent years, many control programmes in sub-Saharan Africa will soon be required to strengthen systems for surveillance in order to further drive transmission to zero. Yet few practical experiences are available to guide control programmes in designing surveillance system components in low transmission, pre-elimination, and elimination phases. Methods A malaria case investigation programme was piloted for 12 weeks in 2012 in Richard Toll district of northern Senegal. Malaria infections (N = 110) were identified through facility-based passive case detection and investigated within three days. Rapid diagnostic tests (RDT) and a brief questionnaire were administered to 5,520 individuals living within the index case compound or within five neighbouring compounds. Results In comparison with family and neighbours, index cases were more likely to be male, age 15–49, and to report travel within the past 15 days that entailed an overnight stay. Twenty-three (0.4%) of family/neighbours were RDT-positive. Potential risk factors for infection among family and neighbours were examined, including: sex, age, occupation, travel history, bed net usage, and residence (index vs neighbouring compound). Adjusting for all factors, relative risk (RR) of infection was associated with residence in the index case household (RR = 3.18, p < 0.05) and recent travel, including travel to Dakar (RR = 19.93, p < 0.001), travel within the region (RR = 9.57, p < 0.01), and to other regions in Senegal (RR = 94.30, p < 0.001). Recent fever among RDT-positive family/neighbours was uncommon (30%). Modifications to testing criteria were examined to optimize the efficiency of secondary case investigations in this population. Limiting blood testing to residents of the index case compound and neighbours with recent travel or fever would have identified 20/23 (87%) of the infections through testing 1,173 individuals

  7. Assessment of climate change impact on water resources in the Upper Senegal basin

    NASA Astrophysics Data System (ADS)

    Lamine Mbaye, Mamadou; Hagemann, Stefan; Haensler, Andreas; Stacke, Tobias; Thierno Gaye, Amadou

    2015-04-01

    This study assesses the potential impacts of climate change on water resources and the effect of statistical bias correction on the projected climate change signal in hydrological variables over the Upper Senegal Basin (West Africa). Original and bias corrected climate data from the regional climate model REMO were used as input for the Max Planck Institute for Meteorology-Hydrology Model (MPI-HM) to simulate river discharge, runoff, soil moisture and evapotranspiration. The results during the historical period (1971-2000) show that using the bias corrected input yields a better representation of the mean river flow regimes and the 10th and 90th percentiles of river flow at the outlet of the Upper Senegal Basin (USB). The Nash-Sutcliffe efficiency coefficient is 0.92 using the bias corrected input, which demonstrates the ability of the model in simulating river flow. The percent bias of 3.88% indicates a slight overestimation of the river flow by the model using the corrected input. The evaluation demonstrates the ability of the bias correction and its necessity for the simulation of historical river regimes. As for the potential changes of hydrological variables by the end of 21st century (2071-2100), a general decrease of river discharge, runoff, actual evapotranspiration, soil moisture is found under two Representative Concentration Pathways (RCP4.5 and RCP8.5) in all simulations. The decrease is higher under RCP8.5 with uncorrected data in the northern basin. However, there are some localized increases in some parts of the basin (e.g Guinean Highlands). The projected climate change signal of these above variables has the same spatial pattern and tendency for the uncorrected and bias corrected data although the magnitude of the corrected signal is somewhat lower than that uncorrected. Furthermore, the available water resources are projected to substantially decrease by more than -50% in the majority of the basin (especially in driest and hottest northern basin

  8. Magnetic susceptibilities of liquid Cr-Au, Mn-Au and Fe-Au alloys

    SciTech Connect

    Ohno, S.; Shimakura, H.; Tahara, S.; Okada, T.

    2015-08-17

    The magnetic susceptibility of liquid Cr-Au, Mn-Au, Fe-Au and Cu-Au alloys was investigated as a function of temperature and composition. Liquid Cr{sub 1-c}Au{sub c} with 0.5 ≤ c and Mn{sub 1-c}Au{sub c} with 0.3≤c obeyed the Curie-Weiss law with regard to their dependence of χ on temperature. The magnetic susceptibilities of liquid Fe-Au alloys also exhibited Curie-Weiss behavior with a reasonable value for the effective number of Bohr magneton. On the Au-rich side, the composition dependence of χ for liquid TM-Au (TM=Cr, Mn, Fe) alloys increased rapidly with increasing TM content, respectively. Additionally, the composition dependences of χ for liquid Cr-Au, Mn-Au, and Fe-Au alloys had maxima at compositions of 50 at% Cr, 70 at% Mn, and 85 at% Fe, respectively. We compared the composition dependences of χ{sub 3d} due to 3d electrons for liquid binary TM-M (M=Au, Al, Si, Sb), and investigated the relationship between χ{sub 3d} and E{sub F} in liquid binary TM-M alloys at a composition of 50 at% TM.

  9. Impact of Climate and Mosquito Vector Abundance on Sylvatic Arbovirus Circulation Dynamics in Senegal

    PubMed Central

    Althouse, Benjamin M.; Hanley, Kathryn A.; Diallo, Mawlouth; Sall, Amadou A.; Ba, Yamar; Faye, Ousmane; Diallo, Diawo; Watts, Douglas M.; Weaver, Scott C.; Cummings, Derek A. T.

    2015-01-01

    Sylvatic arboviruses have been isolated in Senegal over the last 50 years. The ecological drivers of the pattern and frequency of virus infection in these species are largely unknown. We used time series analysis and Bayesian hierarchical count modeling on a long-term arbovirus dataset to test associations between mosquito abundance, weather variables, and the frequency of isolation of dengue, yellow fever, chikungunya, and Zika viruses. We found little correlation between mosquito abundance and viral isolations. Rainfall was a negative predictor of dengue virus (DENV) isolation but a positive predictor of Zika virus isolation. Temperature was a positive predictor of yellow fever virus (YFV) isolations but a negative predictor of DENV isolations. We found slight interference between viruses, with DENV negatively associated with concurrent YFV isolation and YFV negatively associated with concurrent isolation of chikungunya virus. These findings begin to characterize some of the ecological associations of sylvatic arboviruses with each other and climate and mosquito abundance. PMID:25404071

  10. Induction of somatic embryogenesis in gum arabic tree [Acacia senegal (L.) Willd].

    PubMed

    Rathore, Jitendra Singh; Rai, Manoj K; Shekhawat, N S

    2012-10-01

    Factors affecting somatic embryogenesis from immature cotyledon of gum arabic tree [Acacia senegal (L.) Willd.] were investigated. Induction of somatic embryogenesis was influenced by plant growth regulator concentrations and addition of amino acids in medium. Best induction of somatic embryogenesis was obtained on MS medium supplemented with 0.45 μM 2, 4-D, 2.32 μM Kin and 15 mM L-glutamine. L-glutamine plays a significant role in the maturation of somatic embryos and most of embryos attained maturity only on L-glutamine (15 mM) containing medium. Maximum percent (75.0 ± 2.5) germination of somatic embryos was recorded on medium containing 0.22 μM BAP. PMID:24082503

  11. [Can plantar ulcers associated with leprosy be treated in the field. Results of experience in Senegal].

    PubMed

    Grauwin, M Y; Ndiaye, A; Sylla, P M; Gaye, A B; Mane, I; Cartel, J L; Lepers, J P

    1998-01-01

    The introduction of a program for the treatment of plantar ulcers (PU) in field conditions in Senegal was studied. The program was complementary to the Health Education and Protective Footwear to Prevent Disability (POD) initiatives within the Senegalese anti-leprosy program. The wound care given in health centers was coded and simplified. Access to hospitals was made easier for those patients requiring surgery. More than 30% of patients with PU were treated each year, with a mean of 62% cured. An increasing number of leprosy patients have been admitted to regional hospitals for surgery. Never before have patients with signs of leprosy had access to general hospitals. This study emphasizes the need for regular supervision of the individuals treating wounds. PMID:9690320

  12. Landscape Ecology of Sylvatic Chikungunya Virus and Mosquito Vectors in Southeastern Senegal

    PubMed Central

    Diallo, Diawo; Sall, Amadou A.; Buenemann, Michaela; Chen, Rubing; Faye, Oumar; Diagne, Cheikh T.; Faye, Ousmane; Ba, Yamar; Dia, Ibrahima; Watts, Douglas; Weaver, Scott C.; Hanley, Kathryn A.; Diallo, Mawlouth

    2012-01-01

    The risk of human infection with sylvatic chikungunya (CHIKV) virus was assessed in a focus of sylvatic arbovirus circulation in Senegal by investigating distribution and abundance of anthropophilic Aedes mosquitoes, as well as the abundance and distribution of CHIKV in these mosquitoes. A 1650 km2 area was classified into five land cover classes: forest, barren, savanna, agriculture and village. A total of 39,799 mosquitoes was sampled from all classes using human landing collections between June 2009 and January 2010. Mosquito diversity was extremely high, and overall vector abundance peaked at the start of the rainy season. CHIKV was detected in 42 mosquito pools. Our data suggest that Aedes furcifer, which occurred abundantly in all land cover classes and landed frequently on humans in villages outside of houses, is probably the major bridge vector responsible for the spillover of sylvatic CHIKV to humans. PMID:22720097

  13. Impact of climate and mosquito vector abundance on sylvatic arbovirus circulation dynamics in Senegal.

    PubMed

    Althouse, Benjamin M; Hanley, Kathryn A; Diallo, Mawlouth; Sall, Amadou A; Ba, Yamar; Faye, Ousmane; Diallo, Diawo; Watts, Douglas M; Weaver, Scott C; Cummings, Derek A T

    2015-01-01

    Sylvatic arboviruses have been isolated in Senegal over the last 50 years. The ecological drivers of the pattern and frequency of virus infection in these species are largely unknown. We used time series analysis and Bayesian hierarchical count modeling on a long-term arbovirus dataset to test associations between mosquito abundance, weather variables, and the frequency of isolation of dengue, yellow fever, chikungunya, and Zika viruses. We found little correlation between mosquito abundance and viral isolations. Rainfall was a negative predictor of dengue virus (DENV) isolation but a positive predictor of Zika virus isolation. Temperature was a positive predictor of yellow fever virus (YFV) isolations but a negative predictor of DENV isolations. We found slight interference between viruses, with DENV negatively associated with concurrent YFV isolation and YFV negatively associated with concurrent isolation of chikungunya virus. These findings begin to characterize some of the ecological associations of sylvatic arboviruses with each other and climate and mosquito abundance. PMID:25404071

  14. Experience on the management of the first imported Ebola virus disease case in Senegal

    PubMed Central

    Abdoulaye, Bousso; Moussa, Seydi; Daye, Ka; Boubakar, Badiane Seydou; Cor, Sarr Samba; Idrissa, Talla; Mamadou, Ndiaye El Hadj; Oumar, Ba Ibrahima; Tidiane, Ndour Cheikh; Selly, Ly Mamadou; Tacko, Diop Cheikh; Amadou, Diack Papa; Mandiaye, Loume; Mbaye, Diouf; Marie, Coll-Seck Awa

    2015-01-01

    The Ebola virus disease, as a first epidemic in West Africa, stands as the most deadly one throughout history. Guinea, the source of the epidemic, Sierra Leone and Liberia remain the most strongly affected. That epidemic thoroughly destabilized the health system of those countries. Following Nigeria, Senegal received its first imported case from the neighboring Republic of Guinea. In that sub regional psychotic context, such a situation has been handled and managed starting from the potential of a health system that is already suitably structured. The organization of the response, the management of the communication system and the rigorous monitoring of contacts have been decisive in the control of the epidemic. Our countries have to be prepared in order to face health threats, and that is the reason why the need to empower our health systems is important. PMID:26740836

  15. Optimization or Simulation? Comparison of approaches to reservoir operation on the Senegal River

    NASA Astrophysics Data System (ADS)

    Raso, Luciano; Bader, Jean-Claude; Pouget, Jean-Christophe; Malaterre, Pierre-Olivier

    2015-04-01

    Design of reservoir operation rules follows, traditionally, two approaches: optimization and simulation. In simulation, the analyst hypothesizes operation rules, and selects them by what-if analysis based on effects of model simulations on different objectives indicators. In optimization, the analyst selects operational objective indicators, finding operation rules as an output. Optimization rules guarantee optimality, but they often require further model simplification, and can be hard to communicate. Selecting the most proper approach depends on the system under analysis, and the analyst expertise and objectives. We present advantage and disadvantages of both approaches, and we test them for the Manantali reservoir operation rule design, on the Senegal River, West Africa. We compare their performance in attaining the system objectives. Objective indicators are defined a-priori, in order to quantify the system performance. Results from this application are not universally generalizable to the entire class, but they allow us to draw conclusions on this system, and to give further information on their application.

  16. Neoliberal reform and health dilemmas: social hierarchy and therapeutic decision making in Senegal.

    PubMed

    Foley, Ellen E

    2008-09-01

    In this article, I trace the links among neoliberalism, regional ecological decline, and the dynamics of therapeutic processes in rural Senegal. By focusing on illness management in a small rural community, the article explores how economic reform is mediated by existing social structures, and how household social organization in turn influences therapeutic decision making. The illness episodes relayed here demonstrate how the acute economic and social crisis facing the Ganjool region becomes written on the bodies of young men, and how the fault lines of gender and generation shape illness experiences. These narratives also illuminate the tremendous discrepancy between the lived realities of sickness and death, and the idealized models of health participation and empowerment envisioned by the state. Rather than "neoliberal subjects" who behave as rational economic actors, men and women coping with illness are social beings embedded in fields of power characterized by highly stratified household social relations. PMID:19014015

  17. Serological Survey of West Nile Virus in Domestic Animals from Northwest Senegal.

    PubMed

    Davoust, Bernard; Maquart, Marianne; Roqueplo, Cédric; Gravier, Patrick; Sambou, Masse; Mediannikov, Oleg; Leparc-Goffart, Isabelle

    2016-05-01

    In Africa, infection with West Nile virus (WNV) is frequent but almost always asymptomatic in humans and equids. The aim of this study was to identify whether any other domestic animal living in the same enzootic locality may be the sentinel of WNV circulation. In northwest Senegal, blood samples were collected from 283 adult domestic animals (136 sheep, 64 horses, 29 donkeys, 29 goats, 14 cattle, and 11 dogs), in three localities near Keur Momar Sarr. Each serum was tested for WNV immunoglobulin G using enzyme-linked immunosorbent assay. The prevalence among donkeys, horses, dogs, goats, cattle, and sheep was 86.2%, 68.7%, 27.3%, 6.9%, 0%, and 0%, respectively. This survey confirms that equids and dogs could be the best sentinel animals for surveillance of WNV. The ruminants do not play a role in WNV epidemiology. PMID:27002305

  18. Rangewide ploidy variation and evolution in Acacia senegal: a north–south divide?

    PubMed Central

    Odee, David W.; Wilson, Julia; Omondi, Stephen; Perry, Annika; Cavers, Stephen

    2015-01-01

    Knowledge of rangewide variation in DNA content and ploidy level may be valuable in understanding the evolutionary history of a species. Recent studies of Acacia senegal report diploids and occasional tetraploids in the Sudano-Sahelian region of sub-Saharan Africa, but nothing is known about the overall extent of DNA ploidy variation within the species. In this study, we determine the DNA content and ploidy level of A. senegal across its native range, and explore whether the variation is related to its evolutionary and colonization history. We used propidium iodide flow cytometry (FCM) to estimate DNA content (2C value) and infer ploidy in 157 individuals from 54 populations on various tissues, using seeds, fresh leaves, dried leaves and twigs and herbarium specimens. The mean 2C DNA (pg ± s.d.) contents detected were 1.47 ± 0.09, 2.12 ± 0.02, 2.89 ± 0.12, and a single individual with 4.51 pg, corresponding to a polyploid series of diploid, triploid, tetraploid and hexaploid individuals. Diploids were confirmed by chromosome counts (2n = 2x = 26). Most populations (90.7 %) were of single ploidy level, while mixed ploidy populations (9.3 %) comprising mostly diploids (2x+3x, 2x+4x and 2x+6x) were restricted to the Sudano-Sahelian and Indian subcontinent regions, its northern range. The species is predominantly diploid, and no mixed ploidy populations were detected in east and southern Africa, its southern range. The geographic pattern of ploidy variation in conjunction with existing phylogeographic and phylogenetic data of the species suggests that polyploids have occurred multiple times in its evolutionary and recent colonization history, including contemporary ecological timescales. The successful use of external tissues of dried twigs in FCM is new, and presents the opportunity to study numerous other dryland woody species. PMID:25680798

  19. Oceanic influence on seasonal malaria outbreaks over Senegal and Sahel. Predictability using S4CAST model

    NASA Astrophysics Data System (ADS)

    Diouf, Ibrahima; Deme, Abdoulaye; Rodriguez-Fonseca, Belen; Suárez-Moreno, Roberto; Cisse, Moustapha; Ndione, Jacques-André; Thierno Gaye, Amadou

    2014-05-01

    Senegal and, in general, West African regions are affected by important outbreaks of diseases with destructive consequences for human population, livestock and country's economy. The vector-borne diseases such as mainly malaria, Rift Valley Fever and dengue are affected by the interanual to decadal variability of climate. Analysis of the spatial and temporal variability of climate parameters and associated oceanic patterns is important in order to assess the climate impact on malaria transmission. In this study, the approach developed to study the malaria-climate link is predefined by the QWeCI project (Quantifying Weather and Climate Impacts on Health in Developing Countries). Preliminary observations and simulations results over Senegal Ferlo region, confirm that the risk of malaria transmission is mainly linked to climate parameters such as rainfall, temperature and relative humidity; and a lag of one to two months between the maximum of malaria and the maximum of climate parameters as rainfall is observed. As climate variables are able to be predicted from oceanic SST variability in remote regions, this study explores seasonal predictability of malaria incidence outbreaks from previous sea surface temperatures conditions in different ocean basins. We have found causal or coincident relationship between El Niño and malaria parameters by coupling LMM UNILIV malaria model and S4CAST statistiscal model with the aim of predicting the malaria parameters with more than 6 months in advance. In particular, El Niño is linked to an important decrease of the number of mosquitoes and the malaria incidence. Results from this research, after assessing the seasonal malaria parameters, are expected to be useful for decision makers to better access to climate forecasts and application on health in the framework of rolling back malaria transmission.

  20. Enteroviruses and Rhinoviruses: Molecular Epidemiology of the Most Influenza-Like Illness Associated Viruses in Senegal.

    PubMed

    Fall, Amary; Dia, Ndongo; Kébé, Ousmane; Sarr, Fatoumata Diene; Kiori, Davy E; Cissé, El Hadj Abdoul Khadir; Sy, Sara; Goudiaby, Deborah; Richard, Vincent; Diop, Ousmane Madiagne; Niang, Mbayame Ndiaye

    2016-08-01

    Different viruses have been identified as etiologic agents of respiratory tract infections, including severe cases. Among these, human rhinoviruses (HRVs) and human enteroviruses (HEVs) are recognized as leading causes. The present study describes the molecular epidemiology of HRVs and HEVs in Senegal over a 3-year surveillance period. From January 2012 to December 2014, nasopharyngeal and oropharyngeal swabs specimen were collected from patients with influenza-like illness (ILI). A real-time reverse transcription polymerase chain reaction was performed for HRV and HEV detection using the RV16 kit. Two regions were targeted for the molecular characterization of RVs: 5' untranslated region (5'UTR) and viral protein 4/viral protein 2 (VP4/VP2) transition region. For enteroviruses (EVs) phylogeny, VP1 gene was targeted. A total of 4,194 samples were collected. Children up to 5 years accounted for 52.9%. Among them, 1,415 (33.7%) were positive for HRV, 857 (20.4%) for HEV, and 437 cases of dual infections HRV/HEV. HRVs and HEVs were identified significantly in children aged 5 years or less. Only cough and vomiting signs were observed with significant association with viral infection. Both viruses co-circulated all year long with a marked increase of activity during rainy and cold period. All HRV types circulate in Senegal. HRV-A and C groups were the most common. HEV serotyping identified coxsackie B viruses (CBV) only. VP1 region revealed different CBV (CBV1, CBV2, CBV3, CBV4, and CBV5), echoviruses, coxsackieviruses A4-like strains and a poliovirus 2. The results suggest strong year-round respiratory picornavirus activity in children up to 5 years of age. Molecular studies identified a wide variety of RVs along with diverse EVs in samples from patients with ILI. PMID:27246444

  1. What is the real price of hydroelectric production on the Senegal River?

    NASA Astrophysics Data System (ADS)

    Raso, Luciano; Bader, Jean-Claude; Malaterre, Pierre-Olivier

    2014-05-01

    Manantali is an annual reservoir on the Senegal River, located in Mali and serving Senegal and Mauritania. The reservoir is used to regulate the flow for hydroelectric production, in the face of the extremely variable seasonal climate of the region. Manantali has been operative for about 10 years now, exceeding the planned production capacity. The economic benefit comes at a price. Before the dam's construction, the annual flood was the basis of flood recession agriculture, traditionally practiced by the local population. Hydroelectric production requires a more regular flow; therefore flow peaks that used to create the flood are now dumped in the reservoir. Floods are reduced because the current reservoir management privileges hydroelectric production to flood recession agriculture. Moreover, the local water authority is evaluating the construction of 6 more reservoirs, which will enhance even further the controllability of the river flow. This study assesses the externalities of energy production for the agricultural production, quantifying the reduction of flooded surface when energy production is maximized, or alternatively, the loss energy production to maintain a minimum sustainable flood. In addition, we examine the system reliability against extreme events, and how a better use of hydrological information can improve the present reservoir management, in order to find a win-win solution. In this study we employ Stochastic Dual Dynamic Programming (SDDP) methodology. SDDP is a leaner version of Stochastic Dynamic Programming (SDP). SDDP does not suffer of the "curse of dimensionality", and therefore it can be applied to larger systems. In this application we include in the model: i) A semi-distributed hydrological model, ii) the reservoir, iii) the hydraulic routing process within the catchment and from the reservoir to the floodplain.

  2. The prevalence of African animal trypanosomoses and tsetse presence in Western Senegal.

    PubMed

    Seck, M T; Bouyer, J; Sall, B; Bengaly, Z; Vreysen, M J B

    2010-09-01

    In 2005, the Government of Senegal initiated a tsetse eradication campaign in the Niayes and La Petite Côte aiming at the removal of African Animal Trypanosomosis (AAT), which is one of the main constraints to the development of more effective cattle production systems. The target area has particular meteorological and ecological characteristics that provide great potential for animal production, but it is unfortunately still infested by the riverine tsetse species Glossina palpalis gambiensis Vanderplank (Diptera: Glossinidae). The tsetse project in Senegal has adopted an area-wide integrated pest management (AW-IPM) approach that targets the entire tsetse population within a delimited area. During the first phase of the programme, a feasibility study was conducted that included the collection of entomological, veterinary, population genetics, environmental and socioeconomic baseline data. This paper presents the parasitological and serological prevalence data of AAT in cattle residing inside and outside the tsetse-infested areas of the target zone prior to the control effort. At the herd level, a mean parasitological prevalence of 2.4% was observed, whereas a serological prevalence of 28.7%, 4.4%, and 0.3% was obtained for Trypanosoma vivax, T. congolense and T. brucei brucei, respectively. The observed infection risk was 3 times higher for T. congolense and T. vivax in the tsetse-infested than in the assumed tsetse-free areas. Moreover, AAT prevalence decreased significantly with distance from the nearest tsetse captured which indicated that cyclical transmission of the parasites by tsetse was predominant over mechanical transmission by numerous other biting flies present. The importance of these results for the development of a control strategy for the planned AW-IPM campaign is discussed. PMID:21073148

  3. Insecticide susceptibility of Aedes aegypti populations from Senegal and Cape Verde Archipelago

    PubMed Central

    2012-01-01

    Background Two concomitant dengue 3 (DEN-3) epidemics occurred in Cape Verde Archipelago and Senegal between September and October 2009. Aedes aegypti was identified as the vector of these epidemics as several DEN-3 virus strains were isolated from this species in both countries. The susceptibility to pyrethroids, organochlorine, organophosphates and carbamate was investigated in two field strains of Aedes aegypti from both countries using WHO diagnostic bioassay kits in order to monitor their the current status of insecticide susceptibility. Findings The two tested strains were highly resistant to DDT. The Cape Verde strain was found to be susceptible to all others tested insecticides except for propoxur 0.1%, which needs further investigation. The Dakar strain was susceptible to fenitrothion 1% and permethrin 0.75%, but displayed reduced susceptibility to deltamethrin, lambda-cyhalothrin and propoxur. Conclusions As base-line results, our observations stress a careful management of insecticide use for the control of Ae. aegypti. Indeed, they indicate that DDT is no longer efficient for the control of Ae. aegypti populations in Cape Verde and Dakar and further suggest a thorough follow-up of propoxur susceptibility status in both sites and that of deltamethrin and lambda-cyhalothrin in Ae. aegypti populations in Dakar. Thus, regular monitoring of susceptibility is greatly needed as well as the knowing if this observed resistance/susceptibility is focal or not and for observed resistance, the use of biochemical methods is needed with detailed comparison of resistance levels over a large geographic area. Keywords Aedes aegypti, Insecticides, Susceptibility, Cape Verde, Senegal PMID:23088621

  4. Rewriting abortion: deploying medical records in jurisdictional negotiation over a forbidden practice in Senegal.

    PubMed

    Suh, Siri

    2014-05-01

    Boundary work refers to the strategies deployed by professionals in the arenas of the public, the law and the workplace to define and defend jurisdictional authority. Little attention has been directed to the role of documents in negotiating professional claims. While boundary work over induced abortion has been extensively documented, few studies have examined jurisdictional disputes over the treatment of abortion complications, or post-abortion care (PAC). This study explores how medical providers deploy medical records in boundary work over the treatment of complications of spontaneous and induced abortion in Senegal, where induced abortion is prohibited under any circumstance. Findings are based on an institutional ethnography of Senegal's national PAC program over a period of 13 months between 2010 and 2011. Data collection methods included in-depth interviews with 36 health care professionals, observation of PAC services at three hospitals, a review of abortion records at each hospital, and a case review of illegal abortions prosecuted by the state. Findings show that health providers produce a particular account of the type of abortion treated through a series of practices such as the patient interview and the clinical exam. Providers obscure induced abortion in medical documents in three ways: the use of terminology that does not differentiate between induced and spontaneous abortion in PAC registers, the omission of data on the type of abortion altogether in PAC registers, and reporting the total number but not the type of abortions treated in hospital data transmitted to state health authorities. The obscuration of suspected induced abortion in the record permits providers to circumvent police inquiry at the hospital. PAC has been implemented in approximately 50 countries worldwide. This study demonstrates the need for additional research on how medical professionals negotiate conflicting medical and legal obligations in the daily practice of treating

  5. Vibrio cholerae and Vibrio parahaemolyticus detected in seafood products from Senegal.

    PubMed

    Coly, Ignace; Sow, Amy Gassama; Seydi, Malang; Martinez-Urtaza, Jaime

    2013-12-01

    The detection of pathogenic Vibrio in seafood from Senegal has generated five food alerts in the European Union. To investigate the presence and abundance Vibrio cholerae and Vibrio parahaemolyticus in seafood and coastal and estuarine waters, 123 seafood samples and 52 water samples were collected during 2007-2009 from two large seafood markets in Dakar, and from different oceanic and estuarine areas of the country. V. parahaemolyticus was detected in 30.1% of seafood samples, whereas presence of V. cholerae was only found in 1.6%. In water samples, V. parahaemolyticus and V. cholerae were detected in 28.8% and 5.7% of the samples, respectively. Abundance of V. parahaemolyticus in seafood from the fishing areas ranged from <0.3 to 7.5 most probable number (MPN) per gram. In samples from markets, densities of V. parahaemolyticus showed higher values ranging from 0.61 to >110 MPN/g. Densities of V. cholerae in the two positive seafood samples reached values of 0.36 and 0.61 MPN/g, repectively. V. parahaemolyticus strains were found to possess tlh, but not tdh and trh by polymerase chain reaction, and all the strains of V. cholerae were non-O1 or non-O139. These results suggest that the prevalence of high salinities in coastal and estuarine environments of Senegal limits the occurrence of V. parahaemolyticus and V. cholerae, despite warmer temperatures prevailing in seawater environments throughout the year. Furthermore, temperature abuse driven by a deficient cold chain over the distribution and retail sales may represent a major risk due to the postharvest multiplication of these Vibrio pathogens. PMID:24147655

  6. Electrochemistry of Au(II) and Au(III) pincer complexes: determination of the Au(II)-Au(II) bond energy.

    PubMed

    Dann, Thomas; Roşca, Dragoş-Adrian; Wright, Joseph A; Wildgoose, Gregory G; Bochmann, Manfred

    2013-10-01

    The bond energy of the unsupported Au-Au bond in the Au(ii) dimer [(C(∧)N(∧)C)Au]2 and the difference between Au(III)-OH and Au(III)-H bond enthalpies have been determined experimentally by electrochemical methods, with Au-OH and Au-H complexes showing unexpected differences in their reduction pathways, supported by DFT modelling. PMID:24051607

  7. Comparative Medical Ethnobotany of the Senegalese Community Living in Turin (Northwestern Italy) and in Adeane (Southern Senegal)

    PubMed Central

    Ellena, Rachele; Quave, Cassandra L.; Pieroni, Andrea

    2012-01-01

    A medico-ethnobotanical survey was conducted among the Senegalese migrant communities of Turin (Piedmont, NW Italy) and their peers living in Adeane (Casamance, Southern Senegal), both among healers and laypeople. Through 27 in-depth interviews, 71 medicinal plant taxa were recorded and identified in Adeane and 41 in Turin, for a total of 315 different folk remedies recorded in Senegal and 62 in Turin. The large majority of the medicinal plants recorded among Senegalese migrants in Turin were also used in their country of origin. These findings demonstrate the resilience of home remedies among migrants and consequently the role they should have in shaping public health policies devoted to migrant groups in Western Countries, which seek to seriously take into account culturally sensitive approaches, that is, emic health-seeking strategies. PMID:22761638

  8. Magnetoresistance of Au films

    SciTech Connect

    Zhang, D. L.; Song, X. H.; Zhang, X; Zhang, Xiaoguang

    2014-01-01

    Measurement of the magnetoresistance (MR) of Au films as a function of temperature and film thickness reveals a strong dependence on grain size distribution and clear violation of the Kohler s rule. Using a model of random resistor network, we show that this result can be explained if the MR arises entirely from inhomogeneity due to grain boundary scattering and thermal activation of grain boundary atoms.

  9. Magnetoresistance of Au films

    DOE PAGESBeta

    Zhang, D. L.; Song, X. H.; Zhang, X.; Zhang, Xiaoguang

    2014-12-10

    Measurement of the magnetoresistance (MR) of Au films as a function of temperature and film thickness reveals a strong dependence on grain size distribution and clear violation of the Kohler s rule. Using a model of random resistor network, we show that this result can be explained if the MR arises entirely from inhomogeneity due to grain boundary scattering and thermal activation of grain boundary atoms.

  10. High Prevalence of Severe Food Insecurity and Malnutrition among HIV-Infected Adults in Senegal, West Africa

    PubMed Central

    Benzekri, Noelle A.; Sambou, Jacques; Diaw, Binetou; Sall, El Hadji Ibrahima; Sall, Fatima; Niang, Alassane; Ba, Selly; Ngom Guèye, Ndèye Fatou; Diallo, Mouhamadou Baïla; Hawes, Stephen E.; Seydi, Moussa; Gottlieb, Geoffrey S.

    2015-01-01

    Background Malnutrition and food insecurity are associated with increased mortality and poor clinical outcomes among people living with HIV/AIDS; however, the prevalence of malnutrition and food insecurity among people living with HIV/AIDS in Senegal, West Africa is unknown. The objective of this study was to determine the prevalence and severity of food insecurity and malnutrition among HIV-infected adults in Senegal, and to identify associations between food insecurity, malnutrition, and HIV outcomes. Methods We conducted a cross-sectional study at outpatient clinics in Dakar and Ziguinchor, Senegal. Data were collected using participant interviews, anthropometry, the Household Food Insecurity Access Scale, the Individual Dietary Diversity Scale, and chart review. Results One hundred and nine HIV-1 and/or HIV-2 participants were enrolled. The prevalence of food insecurity was 84.6% in Dakar and 89.5% in Ziguinchor. The prevalence of severe food insecurity was 59.6% in Dakar and 75.4% in Ziguinchor. The prevalence of malnutrition (BMI <18.5) was 19.2% in Dakar and 26.3% in Ziguinchor. Severe food insecurity was associated with missing clinic appointments (p = 0.01) and not taking antiretroviral therapy due to hunger (p = 0.02). Malnutrition was associated with lower CD4 cell counts (p = 0.01). Conclusions Severe food insecurity and malnutrition are highly prevalent among HIV-infected adults in both Dakar and Ziguinchor, and are associated with poor HIV outcomes. Our findings warrant further studies to determine the root causes of malnutrition and food insecurity in Senegal, and the short- and long-term impacts of malnutrition and food insecurity on HIV care. Urgent interventions are needed to address the unacceptably high rates of malnutrition and food insecurity in this population. PMID:26529509

  11. Effect of feeding Neem (Azadirachta indica) and Acacia (Acacia senegal) tree foliage on nutritional and carcass parameters in short-eared Somali goats.

    PubMed

    Hailemariam, Samson; Urge, Mengistu; Menkir, Sissay

    2016-02-01

    The study was conducted to determine the effects of dried foliage of Acacia senegal and Neem (Azadirachta indica) tree supplementations on feed intake, nutrient digestibility, growth, and carcass parameters in short-eared Somali goats. Twenty male intact short-eared Somali goat yearlings with an average live weight of 16.2 ± 1.08 (Mean ± SD) were assigned to four treatment groups, which comprised a basal diet of hay alone (T1) and supplementation with the tree foliages. Supplements consisted Neem tree (T2), A. senegal (T3) and the mixture of the two (1:1 ratio; T4) dried foliages. The crude protein (CP) content of Neem tree foliage, A. senegal, and their mixture were 16.92, 17.5 and 17.01 % of dry matter (DM), respectively. Total DM intake and digestibility of DM and organic matter were significantly (P < 0.001) higher for the supplemented groups. CP digestibility was significantly higher (P < 0.01) for goats supplemented with Neem tree (72 %) and A. senegal (67 %). The final body weights were higher (P < 0.05) for the goats supplemented with A. Senegal. An average daily body weight (BW) gain was higher (P < 0.01) in supplemented groups. The hot carcass weight was higher in the group supplemented with A. senegal (8.3 kg) among the supplemented groups, all of which are higher than the control (4.9 kg). It is concluded that the supplementation with tree foliage, especially with A. senegal tree foliage, on grass hay encouraged a better utilization of nutrients and animal performance as compared to goats fed on a basal diet of grass hay only. PMID:26563272

  12. Use of Argon, Corona, and Landsat imagery to assess 30 years of land resource changes in west-central Senegal

    USGS Publications Warehouse

    Tappan, G. Gray; Hadj, Amadou; Wood, Eric C.; Lietzow, Ronald W.

    2000-01-01

    Over the past 35 years, an agricultural area of west-central Senegal has experienced rapid population growth, fast expansion of agricultural lands, a decline in rainfall, and degradation of vegetative and soil resources. Although such changes have not escaped the attention of Senegal's people, its government, and the scientific community the ability to monitor and quantify land resource trends of recent decades has been difficult. Recently available high-resolution satellite photographs from the American Argon and Corona Programs provide coverage of Senegal back to 1963. The photographs make it possible to study and map land resources at the beginning of the Space Age. In this study, we characterize the changes that have occurred in the region from the early 1960s to the mid-1 990s. Early Argon and Corona photographs are used to reconstruct the historical land use and land cover; comparisons are made with assessments from recent Landsat images. Field studies and aerial surveys provide additional insight. The forces of change, driven primarily by population growth and unsustainable agricultural practices, are examined

  13. How to reach clients of female sex workers: a survey by surprise in brothels in Dakar, Senegal.

    PubMed Central

    Espirito Santo, M. E. Gomes do; Etheredge, G. D.

    2002-01-01

    OBJECTIVE: To describe the sampling techniques and survey procedures used in identifying male clients who frequent brothels to buy sexual services from female sex workers in Dakar, Senegal, with the aim of measuring the prevalence of human immunodeficiency virus (HIV) infection and investigating related risk behaviours. METHODS: Surveys were conducted in seven brothels in Dakar, Senegal. Clients were identified "by surprise" and interviewed and requested to donate saliva for HIV testing. RESULTS: Of the 1450 clients of prostitutes who were solicited to enter the study, 1140 (79.8%) agreed to be interviewed; 1083 (95%) of these clients provided saliva samples for testing. Of the samples tested, 47 were positive for HIV-1 or HIV-2, giving an HIV prevalence of 4.4%. CONCLUSION: The procedures adopted were successful in reaching the target population. Men present in the brothels could not deny being there, and it proved possible to explain the purpose of the study and to gain their confidence. Collection of saliva samples was shown to be an excellent method for performing HIV testing in difficult field conditions where it is hard to gain access to the population under study. The surveying of prostitution sites is recommended as a means of identifying core groups for HIV infection with a view to targeting education programmes more effectively. In countries such as Senegal, where the prevalence of HIV infection is still low, interventions among commercial sex workers and their clients may substantially delay the onset of a larger epidemic in the general population. PMID:12378288

  14. Epidemiology and Molecular Characterization of Human Respiratory Syncytial Virus in Senegal after Four Consecutive Years of Surveillance, 2012–2015

    PubMed Central

    Cisse, El Hadj Abdel Kader; Kiori, Davy E.; Sarr, Fatoumata Diene; Sy, Sara; Goudiaby, Debora; Richard, Vincent; Niang, Mbayame Ndiaye

    2016-01-01

    Background The burden of respiratory syncytial virus (RSV) infection remains poorly defined in Africa. To address this, we carried out a descriptive and retrospective pilot study, with a focus on the epidemiology of RSV in Senegal after 4 years of surveillance. Methodology and Results From January 2012 to October 2015 swabs were collected from consenting ILI outpatients. Viral detection was performed using RV16 kit enabling direct subtyping of RSV-A and B. For the molecular characterization of HRSV, the second hypervariable region of the Glycoprotein (G) gene was targeted for sequencing. We enrolled 5338 patients with 2803 children younger than five years of age (52.5%). 610 (11.4%) were positive for RSV infection: 276 (45.2%) were group A infections, 334 (54.8%) were group B infections and 21 (3.4%) were A/B co-infections. RSV detection rate is significantly higher (P < 0.0001) in children below 5 years. We noted that the annual distribution of RSV varied substantially by season and for the predominant subtype. Globally, results show a clear circulation pattern in the second half of each year; between June and September and possibly extended into November. The majority of RSV-A strains from Senegal clustered with strains that were previously assigned NA1 and novel ON1 genotype sequences. RSV-B sequences from Senegal clustered with the BA9 genotype. At the amino acid level, RSV-A strains from Senegal show proximity with the genotype ON1 characterized by a 72 nt insertion in G, resulting in 24 extra amino acids of which 23 are duplications of aa 261–283. Conclusion Globally our results show a clear circulation pattern of RSV in the second half of each year, between June and September and possibly extending into November, with children under 5 being more susceptible. Molecular studies identified the novel strains ON1 and BA9 as the major genotypes circulating in Senegal between 2012 and 2015. PMID:27315120

  15. Antibacterial Au nanostructured surfaces

    NASA Astrophysics Data System (ADS)

    Wu, Songmei; Zuber, Flavia; Brugger, Juergen; Maniura-Weber, Katharina; Ren, Qun

    2016-01-01

    We present here a technological platform for engineering Au nanotopographies by templated electrodeposition on antibacterial surfaces. Three different types of nanostructures were fabricated: nanopillars, nanorings and nanonuggets. The nanopillars are the basic structures and are 50 nm in diameter and 100 nm in height. Particular arrangement of the nanopillars in various geometries formed nanorings and nanonuggets. Flat surfaces, rough substrate surfaces, and various nanostructured surfaces were compared for their abilities to attach and kill bacterial cells. Methicillin-resistant Staphylococcus aureus, a Gram-positive bacterial strain responsible for many infections in health care system, was used as the model bacterial strain. It was found that all the Au nanostructures, regardless their shapes, exhibited similar excellent antibacterial properties. A comparison of live cells attached to nanotopographic surfaces showed that the number of live S. aureus cells was <1% of that from flat and rough reference surfaces. Our micro/nanofabrication process is a scalable approach based on cost-efficient self-organization and provides potential for further developing functional surfaces to study the behavior of microbes on nanoscale topographies.We present here a technological platform for engineering Au nanotopographies by templated electrodeposition on antibacterial surfaces. Three different types of nanostructures were fabricated: nanopillars, nanorings and nanonuggets. The nanopillars are the basic structures and are 50 nm in diameter and 100 nm in height. Particular arrangement of the nanopillars in various geometries formed nanorings and nanonuggets. Flat surfaces, rough substrate surfaces, and various nanostructured surfaces were compared for their abilities to attach and kill bacterial cells. Methicillin-resistant Staphylococcus aureus, a Gram-positive bacterial strain responsible for many infections in health care system, was used as the model bacterial strain. It

  16. Morphometric analysis with open source software to explore shallow hydrogeological features in Senegal and Guinea

    NASA Astrophysics Data System (ADS)

    Fussi, Fabio; Di Leo, Margherita; Bonomi, Tullia; Di Mauro, Biagio; Fava, Francesco; Fumagalli, Letizia; Hamidou Kane, Cheikh; Faye, Gayane; Niang, Magatte; Wade, Souleye; Hamidou, Barry; Colombo, Roberto

    2015-04-01

    Water represents a vital resource for everyone on this Planet, but, for some populations, the access to potable water is not given for granted. Recently, the interest in low cost technical solutions to improve access to ground water in developing countries, especially for people located in remote areas, has increased. Manual drilling (techniques to drill boreholes for water using human or animal power) is well known and practiced for centuries in many countries and represents a valid alternative to increase water access. Lately, this practice has raised the attention of national governments and international organizations. This technique is applicable only where hydrogeological conditions are suitable, namely in presence of thick layers of unconsolidated sediments and a shallow water table Aim of this study is exploring the potential of morphometric analysis to improve the methodology to identify areas with suitable hydrogeological conditions for manual drilling, supporting the implementation of water supply programs that can have great impact on living condition of the population. The characteristics of shallow geological layers are strongly dependent from geomorphological processes and are usually reflected in the morphological characteristics of landforms. Under these hypotheses, we have been investigating the geo-statistical correlation between several morphometric variables and a set of hydrogeological variables used in the estimation of suitability for manual drilling: thickness of unconsolidated sediments, texture, hydraulic conductivity of shallow aquifer, depth of water table. The morphology of two study areas with different landscape characteristics in Guinea and Senegal has been investigated coupling the Free and Open Source Software GRASS GIS and R. Several morphometric parameters have been extracted from ASTER GDEM digital elevation model, and have been compared with a set of hydrogeological characteristics obtained from semi-automatic analysis of

  17. Beneficial Hydrologic Relations Between Evergreen Woody Shrubs and Food Crops In the Peanut Basin, Senegal

    NASA Astrophysics Data System (ADS)

    Bogie, N. A.; Bayala, R.; McCants, T.; Bethel, D.; Diedhiou, I.; Dick, R.; Ghezzehei, T. A.

    2012-12-01

    The soils of the Sahel and surrounding regions are threatened by soil degradation and desertification that can lead to significant reduction in food supply. In Senegal, millet and peanut crops are grown in rotation in fields, where to varying degrees, two native shrubs Piliostigma reticulatum, and Guiera senegalensis are allowed to exist. Previous work established that the presence of shrubs increased moisture content, organic matter, crop yield, and ground water recharge beneath shrub canopies. However, relatively little is known about the mechanism controlling nutrient and water relations between the rhizospheres of the crops and shrubs. Therefore, the objective of this ongoing research is to provide mechanistic explanation for why and how the shrubs aid the crop productivity. This research involves field measurements of: crop yield and physiological responses to water stress, water balance, and meteorological data at two sites in the Peanut Basin of Senegal -- a northern site in Kuer Matar (with annual rainfall of 400-500 mm) for G. senegalensis and a southern site in Nioro du Rip (with 600-800 mm annual rainfall) for P. reticulatum. Although a water balance was performed once in the past, it is important to track water dynamics due to large fluctuations in precipitation and rainfall intensity. Interpretation of current observations is aided by numerical simulations using the HYDRUS 1D model calibrated against field data. Preliminary observations from Nioro du Rip show no significant difference between treatments in leaf area index or leaf water potential throughout the daily cycle (predawn, mid-morning, mid-afternoon, and evening) 30 days after sowing (DAS) and during a period of ample rainfall for crop establishment. There were, however, increases of 12.4mm and 13.0mm in profile moisture storage between sole crop and crop and shrub treatments from 20cm to 250cm depth at Keur Matar and Nioro du Rip, respectively. These profile moisture values come from the

  18. Evaluating the skill of seasonal weather forecasts in predicting aflatoxin contamination of groundnut in Senegal

    NASA Astrophysics Data System (ADS)

    Brak, B.; Challinor, A.

    2011-12-01

    skill in seasonal weather forecasting in West Africa (Senegal) sufficient to predict the occurrence of high (median) aflatoxin concentrations in groundnut at harvest and after some period of storage? For multiple locations in Senegal, aflatoxin contamination (AC) indices estimated using observed weather data from 1999-2010 were compared with AC indices based on gridded seasonal weather forecasts for the same location and year. Pearson correlation coefficients for ACobs and ACpred indices were calculated using all locations combined and, if sufficient weather years without missing values were available, for individual locations to test for regional differences in skill.

  19. Impact of Annual Praziquantel Treatment on Urogenital Schistosomiasis in a Seasonal Transmission Focus in Central Senegal.

    PubMed

    Senghor, Bruno; Diaw, Omar Talla; Doucoure, Souleymane; Seye, Mouhamadane; Diallo, Adiouma; Talla, Idrissa; Bâ, Cheikh T; Sokhna, Cheikh

    2016-03-01

    In Sub-Saharan Africa, urogenital schistosomiasis remains a significant public health problem, causing 150.000 deaths/year with approximately 112 million cases diagnosed. The Niakhar district is a disease hotspot in central Senegal where transmission occurs seasonally with high prevalences. The aim of this study was to determine the effect of annual treatment over 3 years on the seasonal transmission dynamics of S. haematobium in 9 villages in the Niakhar district. Adults and children aged between 5 and 60 years were surveyed from 2011 to 2014. Urine samples were collected door-to-door and examined for S. haematobium eggs at baseline in June 2011, and all participants were treated in August 2011 with PZQ (40 mg/kg). After this initial examination, evaluations were conducted at 3 successive time points from September 2011 to March 2014, to measure the efficacy of the annual treatments and the rates of reinfection. Each year, during the transmission period, from July to November-December, malacological surveys were also carried out in the fresh water bodies of each village to evaluate the infestation of the snail intermediate hosts. At baseline, the overall prevalence of S. haematobium infection was 57.7%, and the proportion of heavy infection was 45.3%, but one month after the first treatment high cure rates (92.9%) were obtained. The overall infection prevalence and proportion of heavy infection intensities were drastically reduced to 4.2% and 2.3%, respectively. The level of the first reinfection in February-March 2012 was 9.5%. At follow-up time points, prevalence levels varied slightly between reinfection and treatment from 9.5% in June 2012 to 0.3% in March 2013, 11.2 in June 2013, and 10.1% April 2014. At the end of the study, overall prevalence was significantly reduced from 57.7% to 10.1%. The overall rate of infested Bulinid snails was reduced after repeated treatment from 0.8% in 2012 to 0.5% in 2013. Repeated annual treatments are suggested to have a

  20. Modeling the Impact of Climate Change on Water Resources in the Senegal River Basin

    NASA Astrophysics Data System (ADS)

    Mbaye, M. L.

    2015-12-01

    In this study we assess the impact of climate change on water resources by using uncorrected and bias corrected data from the regional climate model REMO simulations over the Senegal River Basin. Both simulations were used as input of the Max Planck Institute for Meteorology - Hydrological Model over the Upper Senegal Basin.Applying the bias correction simulations of present day climate (1971-2000) substantially improved for both temporal and spatial variations of the analyzed climate parameters (precipitation, temperature) when compared to observations and independent station data. Additionally, the bias corrected input give better representation of the mean river flow, the low flows (10th percentile) and the high flows (90thpercentile) at the outlet of the USB.For the future, the regional climate model projections for precipitation show a general decrease by the end of 21stcentury (2071-2100) for both scenarios RCP4.5 and RCP8.5 and datasets in the majority of the basin, except the Guinean highlands where a slight increase is found. In case of the potential changes of the maximum consecutive number of dry days and wet days, the northern basin is likely to face the most pronounced increase of dry days and decrease of wet days, although slight increase of heavy rainfall is found with similar spatial patterns in both data. Furthermore, a general temperature increase is projected over the entire basin for both scenarios, but more pronounced under the RCP8.5 scenario. Warm night's percent is found to be higher than warm day's percent. As for the potential changes of the basin's hydrology, a general decrease of river discharge, runoff, actual evapotranspiration, soil moisture is found under RCP4.5 and RCP8.5 in all simulations. The decrease is higher under RCP8.5 with uncorrected data in the northern basin. However, there are some localized increases of runoff in some parts of the basin. Furthermore, the available water resources are projected to substantially decrease

  1. Modelling the Abundances of Two Major Culicoides (Diptera: Ceratopogonidae) Species in the Niayes Area of Senegal.

    PubMed

    Diarra, Maryam; Fall, Moussa; Lancelot, Renaud; Diop, Aliou; Fall, Assane G; Dicko, Ahmadou; Seck, Momar Talla; Garros, Claire; Allène, Xavier; Rakotoarivony, Ignace; Bakhoum, Mame Thierno; Bouyer, Jérémy; Guis, Hélène

    2015-01-01

    In Senegal, considerable mortality in the equine population and hence major economic losses were caused by the African horse sickness (AHS) epizootic in 2007. Culicoides oxystoma and Culicoides imicola, known or suspected of being vectors of bluetongue and AHS viruses are two predominant species in the vicinity of horses and are present all year-round in Niayes area, Senegal. The aim of this study was to better understand the environmental and climatic drivers of the dynamics of these two species. Culicoides collections were obtained using OVI (Onderstepoort Veterinary Institute) light traps at each of the 5 sites for three nights of consecutive collection per month over one year. Cross Correlation Map analysis was performed to determine the time-lags for which environmental variables and abundance data were the most correlated. C. oxystoma and C. imicola count data were highly variable and overdispersed. Despite modelling large Culicoides counts (over 220,000 Culicoides captured in 354 night-traps), using on-site climate measures, overdispersion persisted in Poisson, negative binomial, Poisson regression mixed-effect with random effect at the site of capture models. The only model able to take into account overdispersion was the Poisson regression mixed-effect model with nested random effects at the site and date of capture levels. According to this model, meteorological variables that contribute to explaining the dynamics of C. oxystoma and C. imicola abundances were: mean temperature and relative humidity of the capture day, mean humidity between 21 and 19 days prior a capture event, density of ruminants, percentage cover of water bodies within a 2 km radius and interaction between temperature and humidity for C. oxystoma; mean rainfall and NDVI of the capture day and percentage cover of water bodies for C. imicola. Other variables such as soil moisture, wind speed, degree days, land cover or landscape metrics could be tested to improve the models. Further work

  2. Impact of Annual Praziquantel Treatment on Urogenital Schistosomiasis in a Seasonal Transmission Focus in Central Senegal

    PubMed Central

    Senghor, Bruno; Diaw, Omar Talla; Doucoure, Souleymane; Seye, Mouhamadane; Diallo, Adiouma; Talla, Idrissa; Bâ, Cheikh T.; Sokhna, Cheikh

    2016-01-01

    In Sub-Saharan Africa, urogenital schistosomiasis remains a significant public health problem, causing 150.000 deaths/year with approximately 112 million cases diagnosed. The Niakhar district is a disease hotspot in central Senegal where transmission occurs seasonally with high prevalences. The aim of this study was to determine the effect of annual treatment over 3 years on the seasonal transmission dynamics of S. haematobium in 9 villages in the Niakhar district. Adults and children aged between 5 and 60 years were surveyed from 2011 to 2014. Urine samples were collected door-to-door and examined for S. haematobium eggs at baseline in June 2011, and all participants were treated in August 2011 with PZQ (40 mg/kg). After this initial examination, evaluations were conducted at 3 successive time points from September 2011 to March 2014, to measure the efficacy of the annual treatments and the rates of reinfection. Each year, during the transmission period, from July to November-December, malacological surveys were also carried out in the fresh water bodies of each village to evaluate the infestation of the snail intermediate hosts. At baseline, the overall prevalence of S. haematobium infection was 57.7%, and the proportion of heavy infection was 45.3%, but one month after the first treatment high cure rates (92.9%) were obtained. The overall infection prevalence and proportion of heavy infection intensities were drastically reduced to 4.2% and 2.3%, respectively. The level of the first reinfection in February-March 2012 was 9.5%. At follow-up time points, prevalence levels varied slightly between reinfection and treatment from 9.5% in June 2012 to 0.3% in March 2013, 11.2 in June 2013, and 10.1% April 2014. At the end of the study, overall prevalence was significantly reduced from 57.7% to 10.1%. The overall rate of infested Bulinid snails was reduced after repeated treatment from 0.8% in 2012 to 0.5% in 2013. Repeated annual treatments are suggested to have a

  3. Children of Senegal River Basin show the highest prevalence of Blastocystis sp. ever observed worldwide

    PubMed Central

    2014-01-01

    Background Blastocystis sp. is currently the most common intestinal protist found in human feces and considered an emerging parasite with a worldwide distribution. Because of its potential impact in public health, we reinforced the picture of Blastocystis sp. prevalence and molecular subtype distribution in Africa by performing the first survey of this parasite in Senegal. Methods Stool samples from 93 symptomatic presenting with various gastrointestinal disorders or asymptomatic children living in three villages of the Senegal River Basin were tested for the presence of Blastocystis sp. by non-quantitative and quantitative PCR using primer pairs targeting the SSU rDNA gene. Positive samples were subtyped to investigate the frequency of Blastocystis sp. subtypes in our cohort and the distribution of subtypes in the symptomatic and asymptomatic groups of children. Results By the use of molecular tools, all 93 samples were found to be positive for Blastocystis sp. indicating a striking parasite prevalence of 100%. Mixed infections by two or three subtypes were identified in eight individuals. Among a total of 103 subtyped isolates, subtype 3 was most abundant (49.5%) followed by subtype 1 (28.2%), subtype 2 (20.4%) and subtype 4 (1.9%). Subtype 3 was dominant in the symptomatic group while subtypes 1 and 2 were detected with equal frequency in both symptomatic and asymptomatic groups. The distribution of subtypes was compared with those available in other African countries and worldwide. Comparison confirmed that subtype 4 is much less frequently detected or absent in Africa while it is commonly found in Europe. Potential sources of Blastocystis sp. infection including human-to-human, zoonotic, and waterborne transmissions were also discussed. Conclusions The prevalence of Blastocystis sp. in our Senegalese population was the highest prevalence ever recovered worldwide for this parasite by reaching 100%. All cases were caused by subtypes 1, 2, 3 and 4 with a

  4. [Self-treatment of fever in the northern district of Dakar, Senegal].

    PubMed

    Ndiaye, P; Tal-Dia, A; Diedhiou, A; Juergens-Behr, A; Lemort, J P

    2006-02-01

    Malaria is assimilated with its cardinal symptom, i.e., fever. Treatment of fever with antimalarial drugs is crucial to the prevention of malaria-related death in Senegal. The objective of this study was to analyze fever-treatment practices as a basis for making realistic recommendations for self-treatment in the northern health district of Dakar, Senegal. This cross-sectional study was conducted from March 1 to April 30, 2003. The population included all patients with body temperature higher or equal to 37.5 degrees C (99.5 degrees F) associated with at least one of the following symptoms: headache, shivering, vomiting and diarrhoea. Study endpoints included demographic data and fever treatment modalities including the nature, dosage, and duration of the drugs used. Malaria was suspected in 180 of the 271 patients enrolled in the study. Treatment had already been undertaken in 134 patients including 108 (81%) who had initiated self-treatment. Drugs included antipyretics, antibiotics, and/or antimalarials. Antimalarial drug dosage was incorrect in 84% of those who initiated self-treatment. Dosage errors involved number of daily doses (55%), duration of treatment (13%), or both (32%). Only 45% of patients fully completed treatment. Medical advice was sought in 30% of the cases and drugs were obtained over the counter in pharmacies in 59%. Patients under the age of 15 years were significantly more likely to initiate self-treatment (p=6.10-6), to treat symptoms early, and to use an antimalarial (p=4.10-6). Although self-treatment shortened the delay between onset of symptoms and initiation of treatment, it is likely that indiscriminate and incomplete treatment is responsible for development of resistance to chloroquine in the northern health district of Dakar. Strategies must be adapted to numerous local factors influencing self-treatment including the availability of health-care services and drugs of quality. Special attention must be given to the improvement of

  5. The Predictability of the Sahelian Climate: Seasonal Sahel Rainfall and Onset over Senegal

    NASA Astrophysics Data System (ADS)

    Ndiaye, Ousmane

    The first part of this study addresses the predictability of seasonal rainfall totals in the Sahel region of West Africa. We show that, when driven with observed sea surface temperature (SST), atmospheric General Circulation Models (GCMs) do usually contain information about the observed interannual Sahel rainfall variability, through their predictions of the low-level tropical Atlantic / West Africa wind field. Most current GCMs are unable to directly represent the SST impact on the Sahel's rainfall variability. Therefore, this new result is significant for GCM prediction of Sahel rainfall at seasonal timescales, and potentially other timescales as well. For seasonal predictions, lead-time beyond a month is difficult due to SST developments. The second major result found here is the potential for coupled models to break through the lead-time barrier, with skill superior to that previously reported using empirical or GCM approaches. For the CFS model, skill levels only slightly less than those achieved by the best approaches using observed SST, have been achieved at lead-times of up to six months, utilizing the same low-level regional wind field. The onset of the rains is critical for agriculture. Two homogeneous onset regions over Senegal are defined (southern region and northern region). Both regions experience frequent false onsets. We find relationships between onset date and a mix of large scale boundary layer and regional atmospheric synoptic features. Variables containing information include low level wind, SST, precipitable water and moist static energy. The southern region onset is influenced by the SST gradient over the tropical Atlantic. The northern region is more related to SST in the global tropics. At the synoptic time scale, we find clear propagation of signals from the eastern Sahel: relatively slow for the southern region onset (about 2.5 m/s), with faster propagation typical for the northern region (about 8.5 m/s). The risk of a false onset is

  6. Genetic diversity and phylogenetic relationships in local cattle breeds of Senegal based on autosomal microsatellite markers

    PubMed Central

    Ndiaye, Ndèye Penda; Sow, Adama; Dayo, Guiguigbaza-Kossigan; Ndiaye, Saliou; Sawadogo, Germain Jerôme; Sembène, Mbacké

    2015-01-01

    Aim: In Senegal, uncontrolled cross-breeding of cattle breeds and changes in production systems are assumed to lead to an increase of gene flow between populations. This might constitute a relevant threat to livestock improvement. Therewith, this study was carried out to assess the current genetic diversity and the phylogenetic relationships of the four native Senegalese cattle breeds (Gobra zebu, Maure zebu, Djakoré, and N’Dama). Methods: Genomic DNA was isolated from blood samples of 120 unrelated animals collected from three agro-ecological areas of Senegal according to their phenotypic traits. Genotyping was done using 11 specific highly polymorphic microsatellite makers recommended by Food and Agriculture Organization. The basic measures of genetic variation and phylogenetic trees were computed using bioinformatics’ software. Results: A total of 115 alleles were identified with a number of alleles (Na) at one locus ranging from 6 to 16. All loci were polymorphic with a mean polymorphic information content of 0.76. The mean allelic richness (Rs) lay within the narrow range of 5.14 in N’Dama taurine to 6.10 in Gobra zebu. While, the expected heterozygosity (HE) per breed was high in general with an overall mean of 0.76±0.04. Generally, the heterozygote deficiency (FIS) of 0.073±0.026 was relatively due to inbreeding among these cattle breeds or the occurrence of population substructure. The high values of allelic and gene diversity showed that Senegalese native cattle breeds represented an important reservoir of genetic variation. The genetic distances and clustering trees concluded that the N’Dama cattle were most distinct among the investigated cattle populations. So, the principal component analyses showed qualitatively that there was an intensive genetic admixture between the Gobra zebu and Maure zebu breeds. Conclusions: The broad genetic diversity in Senegalese cattle breeds will allow for greater opportunities for improvement of productivity

  7. Surface morphology and optical properties of porphyrin/Au and Au/porphyrin/Au systems

    NASA Astrophysics Data System (ADS)

    Kalachyova, Yevgeniya; Lyutakov, Oleksiy; Solovyev, Andrey; Slepička, Petr; Švorčík, Vaclav

    2013-12-01

    Porphyrin/Au and Au/porphyrin/Au systems were prepared by vacuum evaporation and vacuum sputtering onto glass substrate. The surface morphology of as-prepared systems and those subjected to annealing at 160°C was studied by optical microscopy, atomic force microscopy, and scanning electron microscopy techniques. Absorption and luminescence spectra of as-prepared and annealed samples were measured. Annealing leads to disintegration of the initially continuous gold layer and formation of gold nanoclusters. An amplification of Soret band magnitude was observed on the Au/meso-tetraphenyl porphyrin (TPP) system in comparison with mere TPP. Additional enhancement of luminescence was observed after the sample annealing. In the case of sandwich Au/porphyrin/Au structure, suppression of one of the two porphyrins' luminescence maxima and sufficient enhancement of the second one were observed.

  8. Antibacterial Au nanostructured surfaces.

    PubMed

    Wu, Songmei; Zuber, Flavia; Brugger, Juergen; Maniura-Weber, Katharina; Ren, Qun

    2016-02-01

    We present here a technological platform for engineering Au nanotopographies by templated electrodeposition on antibacterial surfaces. Three different types of nanostructures were fabricated: nanopillars, nanorings and nanonuggets. The nanopillars are the basic structures and are 50 nm in diameter and 100 nm in height. Particular arrangement of the nanopillars in various geometries formed nanorings and nanonuggets. Flat surfaces, rough substrate surfaces, and various nanostructured surfaces were compared for their abilities to attach and kill bacterial cells. Methicillin-resistant Staphylococcus aureus, a Gram-positive bacterial strain responsible for many infections in health care system, was used as the model bacterial strain. It was found that all the Au nanostructures, regardless their shapes, exhibited similar excellent antibacterial properties. A comparison of live cells attached to nanotopographic surfaces showed that the number of live S. aureus cells was <1% of that from flat and rough reference surfaces. Our micro/nanofabrication process is a scalable approach based on cost-efficient self-organization and provides potential for further developing functional surfaces to study the behavior of microbes on nanoscale topographies. PMID:26648134

  9. HIV Risk among MSM in Senegal: A Qualitative Rapid Assessment of the Impact of Enforcing Laws That Criminalize Same Sex Practices

    PubMed Central

    Poteat, Tonia; Diouf, Daouda; Drame, Fatou Maria; Ndaw, Marieme; Traore, Cheikh; Dhaliwal, Mandeep; Beyrer, Chris; Baral, Stefan

    2011-01-01

    Men who have sex with men (MSM) are at high risk for HIV in Senegal, with a prevalence of 21.5%. In December 2008, nine male HIV prevention workers were imprisoned for “acts against nature” prohibited by Senegalese law. This qualitative study assessed the impact of these arrests on HIV prevention efforts. A purposive sample of MSM in six regions of Senegal was recruited by network referral. 26 in-depth interviews (IDIs) and 6 focus group discussions (FGDs) were conducted in July–August 2009. 14 key informants were also interviewed. All participants reported pervasive fear and hiding among MSM as a result of the December 2008 arrests and publicity. Service providers suspended HIV prevention work with MSM out of fear for their own safety. Those who continued to provide services noticed a sharp decline in MSM participation. An effective response to the HIV epidemic in Senegal should include active work to decrease enforcement of this law. PMID:22194906

  10. Implementation of a High-Dose-Rate Brachytherapy Program for Carcinoma of the Cervix in Senegal: A Pragmatic Model for the Developing World

    SciTech Connect

    Einck, John P.; Hudson, Alana; Shulman, Adam C.; Yashar, Catheryn M.; Dieng, Mamadou M.; Diagne, Magatte; Gueye, Latifatou; Gningue, Fama; Gaye, Pape M.; Fisher, Brandon J.; Mundt, Arno J.; Brown, Derek W.

    2014-07-01

    West Africa has one of the highest incidence rates of carcinoma of the cervix in the world. The vast majority of women do not have access to screening or disease treatment, leading to presentation at advanced stages and to high mortality rates. Compounding this problem is the lack of radiation treatment facilities in Senegal and many other parts of the African continent. Senegal, a country of 13 million people, had a single {sup 60}Co teletherapy unit before our involvement and no brachytherapy capabilities. Radiating Hope, a nonprofit organization whose mission is to provide radiation therapy equipment to countries in the developing world, provided a high-dose-rate afterloading unit to the cancer center for curative cervical cancer treatment. Here we describe the implementation of high-dose-rate brachytherapy in Senegal requiring a nonstandard fractionation schedule and a novel treatment planning approach as a possible blueprint to providing this technology to other developing countries.

  11. Spawning period of Senegal sole, Solea senegalensis, based on juvenile otolith microstructure

    NASA Astrophysics Data System (ADS)

    Vinagre, Catarina; Maia, Anabela; Amara, Rachid; Cabral, Henrique N.

    2013-02-01

    The Senegal sole, Solea senegalensis, is a flatfish species distributed from the Bay of Biscay to the coast of South Africa. Although it is a species of high commercial value its spawning period remains poorly known. In the Tagus estuary, Portugal, two juvenile cohorts of this species colonize two independent nursery areas within the estuarine system. Left lapilli otoliths of these 0-group juveniles were used to estimate age and back-calculate hatch dates, thus allowing the estimation of S. senegalensis spawning period in the Portuguese coast. The two cohorts of S. senegalensis completed the colonization of the two nurseries in July. The ages of juveniles were estimated to range between 46 and 111 days in nursery A, and between 33 and 61 days in nursery B. Hatch dates ranged from April to early June for juveniles colonizing nursery A, and from May to early June for juveniles colonizing nursery B. The mean hatch date in nursery A was the 7th of May, while in nursery B it was the 25th of May. It was concluded that the spawning period for this species off the Portuguese coast was from April to June.

  12. Silurian magmatism in eastern Senegal and its significance for the Paleozoic evolution of NW-Gondwana

    NASA Astrophysics Data System (ADS)

    Fullgraf, Thomas; Ndiaye, Papa Moussa; Blein, Olivier; Buscail, François; Lahondère, Didier; Le Métour, Joël; Sergeev, Sergey; Tegyey, Monique

    2013-02-01

    Submarine basalt and trachyte of the Nandoumba group occur in eastern Senegal within the Bassarides branch of the Mauritanides orogen. The unit forms part of the parautochthonous domain which is stacked between underlying Neoproterozoic to Paleozoic foreland and overlying Variscan nappes. The crystallisation age of the volcanic to subvolcanic rocks has been determined by U-Pb single zircon SHRIMP method at 428 ± 5.2 Ma whereas zircon xenocryst ages vary from 500 to 2200 Ma. The shape of the xenocryst grains document proximal Neo- and Paleoproterozoic and distal Mesoproterozoic provenance areas for assimilated sediments. This is compatible with the Paleoproterozoic Birimian basement and Neoproterozoic cover rocks nearby whereas an origin from the Amazonian craton could be assumed for distal Mesoproterozoic zircons. Geochemical and Sm-Nd isotope whole rock analysis show that basalts of the Nandoumba group are similar to modern transitional to alkaline volcanic lavas in intraplate settings. Those basalts have a deep mantle source with a great contribution of a recycled mantle component such as EM1 and/or EM2. The basalts resemble in their composition those from the Meguma terrane of Nova Scotia which are of similar age suggesting a common source and therefore connection of Meguma with Gondwana during this period. Review of circum-Atlantic Silurian magmatism indicates ongoing fragmentation of NW-Gondwana that started in Cambro/Ordovician times.

  13. [Phlebotomines of Senegal (Diptera: Psychodidae): population and population dynamics of the Mont-Rolland region].

    PubMed

    Ba, Y; Trouillet, J; Thonnon, J; Fontenille, D

    1998-06-01

    Phlebotomine sandflies were captured on a monthly basis from May 1995 to April 1996 in the Mont-Rolland district in Western Senegal. The objectives were to study the population dynamics of sandflies and to make an inventory of the viruses they transmit. Among 10,315 specimens captured, belonging to 14 species, Sergentomyia dubia (35.9%), S. schwetzi (27.7%) and S. buxtoni (24.5%) were the most abundant. Species from the genus Sergentomyia accounted for 99.6% versus 0.4% for the genus Phlebotomus. The sandflies population was observed to peak in February. The most populated resting sites of the captured insects were in decreasing order tree-holes, termite-hills and burrows. S. dubia was the most abundant species captured in tree-holes. It was S. buxtoni in termite-hills, while S. schwetzi was found to dwell most often in burrows. No virus was isolated from 2,114 specimens tested. PMID:9754310

  14. Patterns of a Sylvatic Yellow Fever Virus Amplification in Southeastern Senegal, 2010

    PubMed Central

    Diallo, Diawo; Sall, Amadou A.; Diagne, Cheikh T.; Faye, Oumar; Hanley, Kathryn A.; Buenemann, Michaela; Ba, Yamar; Faye, Ousmane; Weaver, Scott C.; Diallo, Mawlouth

    2014-01-01

    During the wet season of 2010, yellow fever virus (YFV) was detected in field-collected mosquitoes in the Kédougou region in southeastern Senegal. During this outbreak, we studied the association of the abundance of YFV-infected mosquitoes and land cover features to try and understand the dynamics of YFV transmission within the region. In total, 41,234 mosquito females were collected and tested for virus infection in 5,152 pools. YFV was detected in 67 pools; species including Aedes furcifer (52.2% of the infected pools), Ae. luteocephalus (31.3% of the infected pools), Ae. taylori (6.0% of the infected pools) and six other species (10.4% of the infected pools) captured in September (13.4%), October (70.1%), and November (16.4%). Spatially, YFV was detected from mosquitoes collected in all land cover classes but mainly, forest canopies (49.2%). Human infection is likely mediated by Ae. furcifer, the only species found infected with YFV within villages. Villages containing YFV-infected mosquitoes were significantly closer to large forests (> 2 ha) than villages in which no infected mosquitoes were detected. PMID:24615140

  15. Hemophagocytic Syndrome, an Uncommon Complication of Microscopic Polyangitis: A Case Report From Senegal

    PubMed Central

    Cisse, Mouhamadou Moustapha; Abdoul Karim Omar, Daher; Nzambaza, Jean De Dieu; Ba, Sidy; Ndao, Awa Cheikh; Sall, Abibatou; Dial, Cherif Mouhamed; Faye, Maria; Ka, El Hadji Fary; Faye, Moustapha; Lemrabott, Ahmed Tall; Niang, Abdou; Diouf, Boucar

    2015-01-01

    Introduction: We reported a case of hemophagocytic syndrome complicating microscopic polyangitis presented by crescentic glomerulonephritis. Case Presentation: A 22-year-old female patient originated from Dakar, Senegal presented with nephrotic syndrome and rapidly progressive glomerulonephritis. On physical examination, we noticed hyperchromic diffuse punctilious purpura skin lesions predominant on the trunk, the neck and the upper thigh. Immunology investigations revealed strongly positive anti SSA/Ro and anti-SSB. Anti-neutrophil cytoplasmic antibodies had positive results with a peri-nuclear type fluorescence, specific to myeloperoxidase. In optic microscopy, renal biopsy showed a crescentic glomerulonephritis with circumferential cellular and fibrous proliferation affecting 85% of glomeruli. The diagnosis of microscopic polyangitis with renal and skin involvement was retained. The patient received methylprednisolone and cyclophosphamide 700 mg/m2 every 15 days for the first 3 pulses and every 21 days thereafter. After the 5th month, she developed obnubilation, fever and central pancytopenia. Bone marrow aspiration was performed, which showed medullary invasion by macrophages with signs of hemophagocytosis. Diagnosis of hemophagocytic syndrome complicating a microscopic polyangitis was retained and methylprednisolone pulses started. The patient was under hemodialysis after follow-up of about 9 months with stable clinical state. Conclusions: The occurrence of SAM in pauci-autoimmune vasculitis is rarely described, particularly in Africa. Our case is an illustration of the reality of this association. PMID:26866006

  16. Prevalence and Scanning Electron Microscopic Identification of Anoplocephalid Cestodes among Small Ruminants in Senegal

    PubMed Central

    Yanagida, Tetsuya; Ba, Cheikh Tidiane; Marchand, Bernard

    2016-01-01

    This study was undertaken to determine the prevalence of anoplocephalid cestodes in sheep and goats in Senegal. Intestines of 462 sheep and 48 goats were examined; 47.4% of sheep and 6.2% of goats were infected. The species identified and their prevalence were, among sheep, Avitellina centripunctata 38.7%, Moniezia expansa 15.4%, Stilesia globipunctata 16.7%, and Thysaniezia ovilla 0.4%. Among goats, they were M. expansa 6.2% and T. ovilla 2.1%. The prevalence of all species was not statistically different between dry and rainy seasons. The infections were single or multiple. Indeed, 56.2% of sheep were infected by a single species, 37.4% by two species, and 6.4% by three species. For goats, 66.7% were infected by M. expansa and 33.3% by both M. expansa and T. ovilla. Scanning electron microscopic (SEM) observations of tapeworms show the general diagnosis characters of these species. PMID:27597893

  17. Cost-effectiveness of two interventions for the prevention of postpartum hemorrhage in Senegal

    PubMed Central

    Vlassoff, Michael; Diallo, Alioune; Philbin, Jesse; Kost, Kathryn; Bankole, Akin

    2016-01-01

    Objective While several clinical studies have compared the prophylactic efficacy of oxytocin and misoprostol for prevention of postpartum hemorrhage (PPH), no studies have examined these interventions at the community level. This cost-effectiveness analysis is the first to do so. Methods This cost-effectiveness study accompanied a randomized trial comparing the prophylactic effectiveness of misoprostol with that of oxytocin conducted in rural Senegal from June to September 2013 of consenting women delivering in maternity huts. We compared the two interventions, with PPH referrals to a higher level facility being the outcome measure. We calculated costs and effects for two hypothetical cohorts of women delivering during a one-year period, each receiving one of the interventions. A third cohort simulated current standard of care (SOC). A sensitivity analysis was performed to estimate the impact of variation in model assumptions. Results The incremental cost-effectiveness ratios (ICER) for the misoprostol intervention was USD 40 per PPH case averted and USD 120 for oxytocin. In all scenarios, the misoprostol intervention dominated except in the worst-case scenario, where the oxytocin intervention was slightly more cost-effective. Conclusion Our findings suggest that use of misoprostol for PPH prevention would be cost-effective in countries with inadequate maternal health care. PMID:26952348

  18. Downregulation of mouse intestinal Na(+)-coupled glucose transporter SGLT1 by gum arabic (Acacia Senegal).

    PubMed

    Nasir, Omaima; Artunc, Ferruh; Wang, Kan; Rexhepaj, Rexhep; Föller, Michael; Ebrahim, Ammar; Kempe, Daniela S; Biswas, Raja; Bhandaru, Madhuri; Walter, Michael; Mohebbi, Nilufar; Wagner, Carsten A; Saeed, Amal M; Lang, Florian

    2010-01-01

    Intestinal Na(+)-coupled glucose transporter SGLT1 determines the rate of glucose transport, which in turn influences glucose-induced insulin release and development of obesity. The present study explored effects of Gum Arabic (GA), a dietary polysaccharide from dried exudates of Acacia Senegal, on intestinal glucose transport and body weight in wild-type C57Bl/6 mice. Treatment with GA (100 g/l) in drinking water for four weeks did not affect intestinal SGLT1 transcript levels but decreased SGLT1 protein abundance in jejunal brush border membrane vesicles. Glucose-induced jejunal short-circuit currents revealed that GA treatment decreased electrogenic glucose transport. Drinking a 20% glucose solution for four weeks significantly increased body weight and fasting plasma glucose concentrations, effects significantly blunted by simultaneous treatment with GA. GA further significantly blunted the increase in body weight, fasting plasma glucose and fasting insulin concentrations during high fat diet. In conclusion, the present observations disclose a completely novel effect of gum arabic, i.e. its ability to decrease intestinal SGLT1 expression and activity and thus to counteract glucose-induced obesity. PMID:20110681

  19. Environmental hazards of mobile ground spraying with cyanophos and fenthion for quelea control in Senegal.

    PubMed

    Mullié, W C; Diallo, A O; Gadji, B; Ndiaye, M D

    1999-05-01

    Seven roosts of red-billed quelea, Quelea quelea, in the Senegal River Valley and Delta were visited during and after aerial or terrestrial treatments with either Cyanox (cyanophos 500 g a.i. liter-1, five roosts) or Queletox (fenthion 640 g a.i. liter-1, two roosts). The primary goal of the observations was to provide data on environmental effects of cyanophos after mobile ground spraying operations. Twenty-six species of vertebrates (birds, reptile, fish) were found dead or debilitated near the spray sites. Effects on nontarget fauna were most pronounced among owls (cyanophos and fenthion) and blue-naped mousebirds, Urocolius macrourus (fenthion). Among terrestrial invertebrates ants and carabid, and tenebrionid beetles were the most conspicuously affected. Among aquatic invertebrates affected tadpole shrimps, Triops cancriformis, dominated. Extremely high residues were found immediately after spraying on tree leaves in the spillway of a vehicle-mounted Berthoud Super Puma airblast sprayer (up to 1380 mg kg-1) and on birds found dying under these trees (125-11,277 microg bird-1, average 2720 microg bird-1) in two roosts treated with cyanophos. Blue-naped mousebirds were identified as being particularly at risk. Side effects were not dose related. They were most severe after routinely practiced mobile ground spraying applications which led to overdosing. These application methods impose severe environmental hazards, and should be abandoned. PMID:10330314

  20. Increase of malaria attacks among children presenting concomitant infection by Schistosoma mansoni in Senegal

    PubMed Central

    Sokhna, Cheikh; Le Hesran, Jean-Yves; Mbaye, Pape A; Akiana, Jean; Camara, Pape; Diop, Mamadou; Ly, Abdoulaye; Druilhe, Pierre

    2004-01-01

    Helminthic infections concomitant with malaria are common in inter-tropical areas. A recent study showed that mice co-infected with Schistosoma mansoni and Plasmodium chabaudi develop higher P. chabaudi parasitaemia and had a higher mortality rate. This important observation deserved to be further investigated among human populations. Malaria attacks were recorded in 512 children aged 6–15 years living in Richard Toll (Northern Senegal) among whom 336 were infected by S. mansoni, and 175 were not. The incidence rate of malaria attacks was significantly higher among S. mansoni-infected individuals, particularly those carrying the highest worm loads, as compared to uninfected subjects (26.6% versus 16,4 %). In contrast, the rate of malaria attacks was lower, without reaching significance, in medium grade S. mansoni infections. Thus, infection by S. mansoni affects susceptibility to malaria, but this can vary according to the intensity of parasite load. The immunological mechanisms underlying this dual effect need to be further explored. PMID:15544703

  1. Vertical ground motion and historical sea-level records in Dakar (Senegal)

    NASA Astrophysics Data System (ADS)

    Le Cozannet, Gonéri; Raucoules, Daniel; Wöppelmann, Guy; Garcin, Manuel; Da Sylva, Sylvestre; Meyssignac, Benoit; Gravelle, Médéric; Lavigne, Franck

    2015-08-01

    With growing concerns regarding future impacts of sea-level in major coastal cities, the most accurate information is required regarding local sea-level changes with respect to the coast. Besides global and regional sea-level changes, local coastal vertical ground motions can substantially contribute to local changes in sea-level. In some cases, such ground motions can also limit the usefulness of tide-gauge records, which are a unique source of information to evaluate global sea-level changes before the altimetry era. Using satellite synthetic aperture radar interferometry, this study aims at characterizing vertical coastal ground motion in Dakar (Senegal), where a unique century-long record in Africa has been rediscovered. Given the limited number of available images, we use a stacking procedure to compute ground motion velocities in the line of sight over 1992-2010. Despite a complex geology and a rapid population growth and development, we show that the city as a whole is unaffected by differential ground motions larger than 1 mm year-1. Only the northern part of the harbor displays subsidence patterns after 2000, probably as a consequence of land reclamation works. However, these ground motions do not affect the historical tide gauge. Our results highlight the value of the historical sea-level records of Dakar, which cover a 100 year time-span in a tropical oceanic region of Africa, where little data are available for past sea-level reconstructions.

  2. SST patterns and dynamics of the southern Senegal-Gambia upwelling center

    NASA Astrophysics Data System (ADS)

    Ndoye, S.; Capet, X.; Estrade, P.; Sow, B.; Dagorne, D.; Lazar, A.; Gaye, A.; Brehmer, P.

    2014-12-01

    The southern end of the Canary current system comprises of an original upwelling center that has so far received little attention, the Southern Senegal-Gambia Upwelling Center (SSUC). We investigate its dynamical functioning by taking advantage of favorable conditions in terms of limited cloud coverage. Analyses and careful examinations of over 1500 satellite images of sea surface temperature scenes contextualized with respect to wind conditions confirm the regularity and stability of the SSUC dynamical functioning (as manifested by the recurrence and persistence of particular SST patterns). The analyses also reveal subtle aspects of its upwelling structure: shelf break cooling of surface waters consistent with internal tide breaking/mixing; complex interplay between local upwelling and the Mauritanian current off the Cape Verde headland; complexity of the inner-shelf/mid shelf frontal transition. The amplitude of the diurnal cycle suggests that large uncertainties exist in the SSUC heat budget. The studies limitations underscore the need for continuous in situ measurement in the SSUC, particularly of winds.

  3. Identifying high production, low production and degraded rangelands in Senegal with normalized difference vegetation index data

    USGS Publications Warehouse

    Tappan, G. Gray; Wood, Lynette; Moore, Donald G.

    1993-01-01

    Seasonal herbaceous vegetation production on Senegal's native rangelands exhibits high spatial and temporal variability. This variability can be monitored using normalized difference vegetation index (NDVI) data computed from 1-km resolution Advanced Very High Resolution Radiometer (AVHRR) image data. Although annual fluctuations in rainfall account for some of the variability, numerous long-term production patterns are evident in the AVHRR time-series data. Different n productivity reflect variations in the region's climate, topography, soils, and land use. Areas of overgrazing and intensive cultivation have caused long-term soil and vegetation degradation. Rangelands of high and low productivity, and degraded rangelands were identified using NDVI. Time-series image data from 1987 though 1992 were used to map relative rangeland productivity. The results were compared to detailed resource maps on soils, vegetation and land use. Much of the variation in rangeland productivity correlated well to the known distribution of resources. The study developed an approach that identified a number of areas of degraded soils and low vegetation production.

  4. Species and endosymbiont diversity of Bemisia tabaci (Homoptera: Aleyrodidae) on vegetable crops in Senegal.

    PubMed

    Hélène, Delatte; Rémy, Baudin; Nathalie, Becker; Anne-Laure, Girard; Traoré, Ramatoulaye Sidebe; Jean-Michel, Lett; Bernard, Reynaud

    2015-03-01

    Bemisia tabaci-transmitted geminiviruses are one of the major threats on cassava and vegetable crops in Africa. However, to date, few studies are available on the diversity of B. tabaci and their associated endosymbionts in Africa. More than 28 species have been described in the complex of B. tabaci cryptic species; among them, 2 are invasive pests worldwide: MED and MEAM1. In order to assess the species diversity of B. tabaci in vegetable crops in Senegal, several samplings in different localities, hosts and seasons were collected and analyzed with nuclear (microsatellite) and mitochondrial (COI) markers. The bacterial endosymbiont community was also studied for each sample. Two species were detected: MED Q1 and MEAM1 B. Patterns of MED Q1 (dominance on most of the samples and sites, highest nuclear and mitochondrial diversity and broader secondary endosymbiont community: Hamiltonella, Cardinium, Wolbachia and Rickettsia), point toward a predominant resident begomovirus vector group for MED Q1 on market gardening crops. Furthermore, the lower prevalence of the second species MEAM1 B, its lower nuclear and mitochondrial diversity and a narrower secondary endosymbiont community (Hamiltonella/Rickettsia), indicate that this genetic group is exotic and results from a recent invasion in this area. PMID:24789572

  5. Assessing drivers of full adoption of test and treat policy for malaria in Senegal.

    PubMed

    Faust, Christina; Zelner, Jonathan; Brasseur, Philippe; Vaillant, Michel; Badiane, Malick; Cisse, Moustafa; Grenfell, Bryan; Olliaro, Piero

    2015-07-01

    Malaria treatment policy has changed from presumptive treatment to targeted "test and treat" (T&T) with malaria rapid diagnostic tests (RDTs) and artemisinin combination therapy (ACT). This transition involves changing behavior among health providers, meaning delays between introduction and full implementation are recorded in almost every instance. We investigated factors affecting successful transition, and suggest approaches for accelerating uptake of T&T. Records from 2000 to 2011 from health clinics in Senegal where malaria is mesoendemic were examined (96,166 cases). The study period encompassed the implementation of national T&T policy in 2006. Analysis showed that adherence to test results is the first indicator of T&T adoption and is dependent on accumulation of experience with positive RDTs (odds ratio [OR]: 0.55 [P ≤ 0.001], 95% confidence interval [CI]: 0.53-0.58). Reliance on tests for malaria diagnosis (rather than presumptive diagnosis) followed after test adherence is achieved, and was also associated with increased experience with positive RDTs (OR: 0.60 [P ≤ 0.001], 95% CI: 0.58-0.62). Logistic models suggest that full adoption of T&T clinical practices can occur within 2 years, that monitoring these behavioral responses rather than RDT or ACT consumption will improve evaluation of T&T uptake, and that accelerating T&T uptake by focusing training on adherence to test results will reduce overdiagnosis and associated health and economic costs in mesoendemic regions. PMID:25962776

  6. Prevalence and Scanning Electron Microscopic Identification of Anoplocephalid Cestodes among Small Ruminants in Senegal.

    PubMed

    Ndom, Mallé; Diop, Gora; Quilichini, Yann; Yanagida, Tetsuya; Ba, Cheikh Tidiane; Marchand, Bernard

    2016-01-01

    This study was undertaken to determine the prevalence of anoplocephalid cestodes in sheep and goats in Senegal. Intestines of 462 sheep and 48 goats were examined; 47.4% of sheep and 6.2% of goats were infected. The species identified and their prevalence were, among sheep, Avitellina centripunctata 38.7%, Moniezia expansa 15.4%, Stilesia globipunctata 16.7%, and Thysaniezia ovilla 0.4%. Among goats, they were M. expansa 6.2% and T. ovilla 2.1%. The prevalence of all species was not statistically different between dry and rainy seasons. The infections were single or multiple. Indeed, 56.2% of sheep were infected by a single species, 37.4% by two species, and 6.4% by three species. For goats, 66.7% were infected by M. expansa and 33.3% by both M. expansa and T. ovilla. Scanning electron microscopic (SEM) observations of tapeworms show the general diagnosis characters of these species. PMID:27597893

  7. Cattle and cultivators: A study of competition over natural resources in north Senegal

    USGS Publications Warehouse

    Freudenberger, Karen Schoonmaker; Wood, Eric

    1998-01-01

    This study presents an analysis of the interaction of humans and their environment in the arid Sahel ian zone of northern Senegal. It compares a pastoral community which lives primarily from the production of livestock and a farming community whose activities have traditionally centered on crop production. Living side by side but following different strategies for securing their livelihoods, these groups find themselves in increasing conflict over how the diminishing resources of the area should be used. The pastoral livelihood system, as practiced in the case study community of Maka Ndandary, is essentially conservationist in its approach to natural resources. It regulates the activities of community members toward the environment and employs diverse strategies to protect local resources against incursion by outsiders. The agricultural village, represented by the case study of Teud Bitty, takes a much more extractive approach to its resources. As resources have diminished over time, the villagers have become even more aggressive in their attempts to exploit what remains, whether soils or trees ... both within and outside their territory.

  8. Study of African Dust with Multi-Wavelength Raman Lidar During "Shadow" Campaign in Senegal

    NASA Astrophysics Data System (ADS)

    Veselovskii, Igor; Goloub, Philippe; Podvin, Thierry; Bovchaliuk, Valentyn; Tanre, Didier; Derimian, Yevgeny; Korenskiy, Mikhail; Dubovik, Oleg

    2016-06-01

    West Africa and the adjacent oceanic regions are very important locations for studying dust properties and their influence on weather and climate. The SHADOW (Study of SaHAran Dust Over West Africa) campaign is performing a multi-scale and multi-laboratory study of aerosol properties and dynamics using a set of in situ and remote sensing instruments at an observation site located at IRD (Institute for Research and Development) Center, Mbour, Senegal (14°N, 17°W). In this paper, we present the results of lidar measurements performed during the first phase of SHADOW which occurred in March-April, 2015. The multiwavelength Mie-Raman lidar acquired 3β+2α+1δ measurements during this period. This set of measurements has permitted particle intensive properties such as extinction and backscattering Ångström exponents (BAE) for 355/532 nm wavelengths corresponding lidar ratios and depolarization ratio at 532 nm to be determined. The backscattering Ångström exponent during the dust episodes decreased to ~-0.7, while the extinction Ångström exponent though being negative, was greater than -0.2. Low values of BAE can likely be explained by an increase in the imaginary part of the dust refractive index at 355 nm compared to 532 nm.

  9. Arboreal nesting as anti-predator adaptation by savanna chimpanzees (Pan troglodytes verus) in southeastern Senegal.

    PubMed

    Pruetz, J D; Fulton, S J; Marchant, L F; McGrew, W C; Schiel, M; Waller, M

    2008-04-01

    Chimpanzees (Pan troglodytes) make nests for resting and sleeping, which is unusual for anthropoid primates but common to all great apes. Arboreal nesting has been linked to predation pressure, but few studies have tested the adaptive nature of this behavior. We collected data at two chimpanzee study sites in southeastern Senegal that differed in predator presence to test the hypothesis that elevated sleeping platforms are adaptations for predator defense. At Assirik in the Parc National du Niokolo-Koba, chimpanzees face four species of large carnivore, whereas at Fongoli, outside national park boundaries, humans have exterminated almost all natural predators. We quantified the availability of vegetation at the two sites to test the alternative hypothesis that differences in nesting reflect differences in habitat structure. We also examined possible sex differences in nesting behavior, community demographic differences, seasonality and nest age differences as variables also potentially affecting nest characteristics and nesting behavior between the two sites. Chimpanzees at Fongoli nested at lower heights and farther apart than did chimpanzees at Assirik and sometimes made nests on the ground. The absence of predators outside of the national park may account for the differences in nest characteristics at the two sites, given the similarities in habitat structure between Fongoli and Assirik. However, Fongoli chimpanzees regularly build arboreal nests for sleeping, even under minimal predation pressure, and this requires explanation. PMID:18161774

  10. Geographic information system as country-level development and monitoring tool, Senegal example

    USGS Publications Warehouse

    Moore, Donald G.; Howard, Stephen M.

    1990-01-01

    Geographic information systems (GIS) allow an investigator the capability to merge and analyze numerous types of country-level resource data. Hypothetical resource analysis applications in Senegal were conducted to illustrate the utility of a GIS for development planning and resource monitoring. Map and attribute data for soils, vegetation, population, infrastructure, and administrative units were merged to form a database within a GIS. Several models were implemented using a GIS to: analyze development potential for sustainable dryland agriculture; prioritize where agricultural development should occur based upon a regional food budget; and monitor dynamic events with remote sensing. The steps for implementing a GIS analysis are described and illustrated, and the use of a GIS for conducting an economic analysis is outlined. Using a GIS for analysis and display of results opens new methods of communication between resource scientists and decision makers. Analyses yielding country-wide map output and detailed statistical data for each level of administration provide the advantage of a single system that can serve a variety of users.

  11. [Prevalence of intestinal parasitis at the King Baudouin health center of Guediawaye (Senegal)].

    PubMed

    Ndir, I; Gaye, A; Sy, M; Gaye, O; Ndir, O

    2002-01-01

    A prospective study carrying on 302 samples of stools of aged children of 0 to 15 years has been achieved between January 02 and April 11 2001 in the center of health Roi Baudouin of Guediawaye (SENEGAL) to appreciate the prevalence of intestinal parasitis. For every child, we made a scotch test, a macroscopic exam of stools and a microscopic exam to the direct analysis and after concentration by the method of RITCHIE simplified. The global prevalence is 56,62%. Ascaris lumbricoides arrived in head with 34,17%, follow-up of Giardia lamblia (22,50%), Trichirus trichiura (22,08%) and Amoeba (14,58%). The prevalence varied with age and the children who are 11 to 15 years have the indication of infestation the most elevated (75,86%): The difference of prevalence to the sex and according to the presence or no current water is not meaningful. On the other hand topics to weak standard of living have an indication elevated parasitis with 66,05%. So measures of efficient struggle must be undertaken to combat these intestinal parasitis. PMID:15776669

  12. Subsidence, extension and thermal history of the West African margin in Senegal

    NASA Astrophysics Data System (ADS)

    Brun, Marie Véronique Latil; Lucazeau, Francis

    1988-10-01

    The subsidence of the Atlantic margin in Senegal clearly shows two rapid stages related to the formation of (1) the Central Atlantic during the early Jurassic (around 200 Ma), and (2) the Equatorial Atlantic during the Cretaceous (100 Ma). A simple model of extension is used to interpret the subsidence history and to derive the thermal evolution of this basin. The present-day gravity, bathymetry, bottom hole temperatures (BHT) in oil exploration boreholes and heat flow density are used to control the validity of the model. Two cross sections from the outcropping basement to oceanic crust are used, one in Casamance and the other one at the south to latitude of Dakar. The model can fully explain the first-order subsidence history as well as the present-day observations, and therefore can provide valuable information about the thermal evolution of sediments and about the structure of the continental crust along the margin. Comparisons with the opposite margin in North America (Blake Plateau and Carolina trough) indicate a rather different evolution (the North American margin did not undergo the second stage of rifting) and a different crustal structure (crustal thinning is less important on the African margin).

  13. Sexual Selection of Human Cooperative Behaviour: An Experimental Study in Rural Senegal

    PubMed Central

    Tognetti, Arnaud; Berticat, Claire; Raymond, Michel; Faurie, Charlotte

    2012-01-01

    Human cooperation in large groups and between non-kin individuals remains a Darwinian puzzle. Investigations into whether and how sexual selection is involved in the evolution of cooperation represent a new and important research direction. Here, 69 groups of four men or four women recruited from a rural population in Senegal played a sequential public-good game in the presence of out-group observers, either of the same sex or of the opposite sex. At the end of the game, participants could donate part of their gain to the village school in the presence of the same observers. Both contributions to the public good and donations to the school, which reflect different components of cooperativeness, were influenced by the sex of the observers. The results suggest that in this non-Western population, sexual selection acts mainly on men’s cooperative behaviour with non-kin, whereas women’s cooperativeness is mainly influenced by nonsexual social selection. PMID:22984503

  14. Muted voices: HIV/AIDS and the young people of Burkina Faso and Senegal.

    PubMed

    Rosendal Østergaard, Lise; Samuelsen, Helle

    2004-11-01

    This article explores the discrepancies between the vocal public discourse on HIV/AIDS and sexuality as generally encouraged by policy-makers and donor communities in Africa, and the often hushed voices of their target groups: young people in African communities. Based on fieldwork among urban youth in Senegal and Burkina Faso, we describe the silence of young people with regard to HIV/AIDS and sexuality as a social phenomenon, with focus given to family relations, peer relations and gender aspects in partnerships. Drawing on Foucault and Morrell, an inability and unwillingness to speak about HIV/AIDS and sexuality are analysed as a response to an everyday life characterised by uncertainty. This response represents a certain degree of resistance, while it constitutes a major barrier to any HIV/AIDS prevention effort. Finally, we stress that despite great constraints in their everyday lives, young people have some room to manoeuvre and are able to apply some negotiating strategies to reduce sexually-related health risks. PMID:25875058

  15. [Waste management from dental care in the health districts of Dakar, Senegal].

    PubMed

    Faye, D; Mbacké Lo, C M; Kanouté, A

    2014-01-01

    Management of medical waste is becoming an increasing public health concerns, especially as these waste treatment methods can themselves create both health and environmental risks. The objective of the study was to evaluate the management of waste from dental care in Dakar. A cross-sectional, descriptive study of dental services in Dakar, based on a questionnaire was used to determine the knowledge and attitudes of dentists on the management of dental waste. All practitioners stated that their offices had waste bins, 81.2% using plastic bags; 73.2% reported that the bins were washed and disinfected an average of once a day. Only 7.2% of the offices or facilities had an autoclave, and 5.8% an incinerator. Three quarters of the respondents did not know how to dispose of contaminated waste and none of them had conducted a study to estimate the quantity of their departmental waste. The management of waste from dental care is not structured in Senegal nor in most developing countries. Moreover, the gaps and ineffectiveness of legislation result in major threats to public health and the environment. The government should focus, among other things, on stakeholder awareness and training, by providing facilities with the resources necessary to contribute to sustainable development through the management of dental waste. PMID:25499629

  16. Policy perspectives and attitudes towards mental health treatment in rural Senegal

    PubMed Central

    2014-01-01

    Background Mental health is often given low priority in health policy planning, particularly in developing countries. Several international health bodies, including the World Health Organization, recommend integrating mental health into primary care settings to reduce mortality and morbidity associated with mental illness, particularly in low-resource settings. Objective This study explores health care workers' and policy stakeholders’ knowledge and attitudes regarding mental illness, interactions with patients in the community, and perceived training needs at a health clinic in rural southeastern Senegal. Interviews were conducted with eight key informant medical staff members and community health workers. Methods Interview data were analyzed and interpreted using a qualitative content analysis based on the grounded theory approach. Results The findings indicate that staff members encounter many patients with emotional/psychological problems or mental illnesses, and they employ various strategies in treating these patients. Respondents also highlighted the need for more training to address and diagnose mental health problems, especially severe psychiatric illnesses. Conclusions Findings are used to discuss recommendations for developing a comprehensive mental health primary care treatment approach that includes screening patients for mental health problems screening, incorporating rural villagers' attitudes and beliefs about mental illness into treatment, and utilizing community health workers—who are often a first health contact for many—to work with the medical staff to identify mental health problems. PMID:24646335

  17. Point-of-sale promotion of breastmilk substitutes and commercially produced complementary foods in Cambodia, Nepal, Senegal and Tanzania.

    PubMed

    Champeny, Mary; Pereira, Catherine; Sweet, Lara; Khin, Mengkheang; Ndiaye Coly, Aminata; Sy Gueye, Ndeye Yaga; Adhikary, Indu; Dhungel, Shrid; Makafu, Cecilia; Zehner, Elizabeth; Huffman, Sandra L

    2016-04-01

    In order to assess the prevalence of point-of-sale promotions of infant and young child feeding products in Phnom Penh, Cambodia; Kathmandu Valley, Nepal; Dakar Department, Senegal; and Dar es Salaam, Tanzania, approximately 30 retail stores per site, 121 in total, were visited. Promotional activity for breastmilk substitutes (BMS) and commercially produced complementary foods in each site were recorded. Point-of-sale promotion of BMS occurred in approximately one-third of sampled stores in Phnom Penh and Dakar Department but in 3.2% and 6.7% of stores in Kathmandu Valley and Dar es Salaam, respectively. Promotion of commercially produced complementary foods was highly prevalent in Dakar Department with half of stores having at least one promotion, while promotions for these products occurred in 10% or less of stores in the other three sites. While promotion of BMS in stores is legal in Senegal, it is prohibited in Cambodia without prior permission of the Ministry of Health/Ministry of Information and prohibited in both Nepal and Tanzania. Strengthening legislation in Senegal and enforcing regulations in Cambodia could help to prevent such promotion that can negatively affect breastfeeding practices. Key messages Even in countries such as Cambodia, Nepal and Tanzania where point-of-sale promotion is restricted, promotions of BMS were observed (in nearly one-third of stores in Phnom Penh and less than 10% in Dar es Salaam and Kathmandu). Limited promotion of commercially produced complementary foods was evident (less than 10% of stores had a promotion for such foods), except in Dakar Department, where promotions were found in half of stores. Efforts are needed to strengthen monitoring, regulation and enforcement of restrictions on the promotion of BMS. Manufacturers and distributors should take responsibility for compliance with national regulations and global policies pertaining to the promotion of breastmilk substitutes. PMID:27061961

  18. Community-acquired diarrhea among children and adults in urban settings in Senegal: clinical, epidemiological and microbiological aspects

    PubMed Central

    2013-01-01

    Background Only limited data are available relating to the etiology of diarrhea in children and adults in Senegal. The aim of this prospective study was to describe the epidemiology and etiology of community-acquired diarrheal infections in children and adults living in urban settings. Methods A prospective study was carried out from March 2009 to December 2010, in the urban region of Dakar, Senegal. Patients with acute diarrhea were enrolled, interviewed to collect their clinical history, and their stools were tested for bacteria, virus and parasites. Results A total of 223 patients (including 112 children younger than five years old) with diarrhea were included. At least one enteropathogen was detected in 81% (180/223) of the patients: 29% (64/223) had bacterial infections (mainly diarrheagenic E. coli and Shigella spp), 21% (39/185) viral infections (mainly rotavirus) and 14% (31/223) parasitic infections. Co-infection was identified in 17.8% (32/180) of the patients. Viral infection was significantly more frequent in children under five years old during the dry season. Bacteria and parasites were equally frequent in all age groups. There was a seasonal variation of bacterial infections during the study period, with a higher proportion of infections being bacterial, and due to Salmonella spp. in particular, during the rainy season. Conclusion Our study suggests that in urban settings in Senegal, rotavirus is the principal cause of pediatric diarrhea during the dry season and that the proportion of bacterial infections seems to be higher during the rainy season. Further work is needed to document the burden of diarrheal diseases in sub-Saharan urban communities and to identify risk factors, including those linked to the rapid and unplanned urbanization in Africa. PMID:24321175

  19. Low and seasonal malaria transmission in the middle Senegal River basin: identification and characteristics of Anopheles vectors

    PubMed Central

    2012-01-01

    Background During the last decades two dams were constructed along the Senegal River. These intensified the practice of agriculture along the river valley basin. We conducted a study to assess malaria vector diversity, dynamics and malaria transmission in the area. Methods A cross-sectional entomological study was performed in September 2008 in 20 villages of the middle Senegal River valley to evaluate the variations of Anopheles density according to local environment. A longitudinal study was performed, from October 2008 to January 2010, in 5 selected villages, to study seasonal variations of malaria transmission. Results Among malaria vectors, 72.34% of specimens collected were An. arabiensis, 5.28% An. gambiae of the S molecular form, 3.26% M form, 12.90% An. pharoensis, 4.70% An. ziemanni, 1.48% An. funestus and 0.04% An. wellcomei. Anopheles density varied according to village location. It ranged from 0 to 21.4 Anopheles/room/day and was significantly correlated with the distance to the nearest ditch water but not to the river. Seasonal variations of Anopheles density and variety were observed with higher human biting rates during the rainy season (8.28 and 7.55 Anopheles bite/man/night in October 2008 and 2009 respectively). Transmission was low and limited to the rainy season (0.05 and 0.06 infected bite/man/night in October 2008 and 2009 respectively). During the rainy season, the endophagous rate was lower, the anthropophagic rate higher and L1014F kdr frequency higher. Conclusions Malaria vectors are present at low-moderate density in the middle Senegal River basin with An. arabiensis as the predominant species. Other potential vectors are An. gambiae M and S form and An. funestus. Nonetheless, malaria transmission was extremely low and seasonal. PMID:22269038

  20. Effect of Inoculation of Acacia senegal mature trees with Mycorrhiza and Rhizobia on soil properties and microbial community structure

    NASA Astrophysics Data System (ADS)

    Assigbetsé, K.; Ciss, I.; Bakhoum, N.; Dieng, L.

    2012-04-01

    Inoculation of legume plants with symbiotic microorganisms is widely used to improve their development and productivity. The objective of this study was to investigate the effect of inoculation of Acacia senegal mature trees with rhizobium (Sinorhizobium) and arbuscular mycorrhizal fungus (G. mosseae, G. fasciculatum, G. intraradices) either singly or in combination, on soil properties, activity and the genetic structure of soil microbial communities. The experiment set up in Southern Senegal consisted of 4 randomized blocks of A. senegal mature trees with 4 treatments including inoculated trees with Rhizobium (R), mycorrhizal fungus (M) and with Rhizobium+mycorhizal fungus (RM) and non-inoculated control (CON). Soil were sampled 2 years after the inoculation. Soil pH, C and N and available P contents were measured. The microbial abundance and activity were measured in terms of microbial biomass C (MBC) and basal soil respiration. The community structure of the total bacterial, diazotrophic and denitrifying communities was assessed by denaturing gradient gel electrophoresis of 16S rDNA, nifH and nirK genes respectively. Inoculations with symbiont under field conditions have increased soil pH. The C and N contents were enhanced in the dual-inoculated treatments (RM). The mycorrhized treatment have displayed the lowest available P contents while RM and R treatments exhibited higher contents rates. The microbial biomass C rates were higher in treatments co-inoculated with AM fungi and Rhizobium than in those inoculated singly with AM fungi or Rhizobium strains. The basal soil respiration were positively correlated to MBC, and the highest rates were found in the co-inoculated treatments. Fingerprints of 16S rDNA gene exhibited similar patterns between inoculated treatments and the control showing that the inoculation of mature trees have not impacted the total bacterial community structure. In contrast, the inoculated treatments have displayed individually different

  1. From the Cross (and Crescent) to the Cedar and Back Again: Transnational Religion and Politics Among Lebanese Christians in Senegal

    PubMed Central

    Leichtman, Mara A.

    2013-01-01

    This article examines the changing relationship between religion, secularism, national politics, and identity formation among Lebanese Christians in Senegal. Notre Dame du Liban, the first Lebanese religious institution in West Africa, draws on its Lebanese “national” character to accommodate Lebanese Maronite Catholic and Greek Orthodox Christians in Dakar, remaining an icon of “Lebanese” religion, yet departing from religious sectarianism in Lebanon. As such, transnational religion can vary from national religion, gaining new resonances and reinforcing a wider “secular” ethno-national identity. PMID:24077518

  2. Final report of the safety assessment of Acacia catechu gum, Acacia concinna fruit extract, Acacia dealbata leaf extract, Acacia dealbata leaf wax, Acacia decurrens extract, Acacia farnesiana extract, Acacia farnesiana flower wax, Acacia farnesiana gum, Acacia senegal extract, Acacia senegal gum, and Acacia senegal gum extract.

    PubMed

    2005-01-01

    These ingredients are derived from various species of the acacia plant. Only material derived from Acacia senegal are in current use according to industry data. The concentration at which these ingredients are reported to be used ranges from 9% in mascara to 0.0001% in tonics, dressings, and other hair-grooming aids. Gum arabic is a technical name for Acacia Senegal Gum. Gum arabic is comprised of various sugars and glucuronic acid residues in a long chain of galactosyl units with branched oligosaccharides. Gum arabic is generally recognized as safe as a direct food additive. Little information is available to characterize the extracts of other Acacia plant parts or material from other species. Acacia Concinna Fruit Extract was generally described as containing saponins, alkaloids, and malic acid with parabens and potassium sorbate added as preservatives. Cosmetic ingredient functions have been reported for Acacia Decurrens Extract (astringent; skin-conditioning agent--occlusive) and Acacia Farnesiana Extract (astringent), but not for the other Acacias included in this review. Toxicity data on gum arabic indicates little or no acute, short-term, or subchronic toxicity. Gum arabic is negative in several genotoxicity assays, is not a reproductive or developmental toxin, and is not carcinogenic when given intraperitoneally or orally. Clinical testing indicated some evidence of skin sensitization with gum arabic. The extensive safety test data on gum arabic supports the safety of Acacia Senegal Gum and Acacia Senegal Gum Extract, and it was concluded that these two ingredients are safe as used in cosmetic formulations. It was not possible, however, to relate the data on gum arabic to the crude Acacias and their extracts from species other than Acacia senegal. Therefore, the available data were considered insufficient to support the safety of Acacia Catechu Gum, Acacia Concinna Fruit Extract, Acacia Dealbata Leaf Extract, Acacia Dealbata Leaf Wax, Acacia Decurrens

  3. Fatal Cases of Gestational Trophoblastic Neoplasia in a National Trophoblastic Disease Reference Center in Dakar Senegal

    PubMed Central

    Gueye, Mamour; Ndiaye-Gueye, Mame Diarra; Kane Gueye, Serigne Modou; Moreau, Jean Charles

    2016-01-01

    Objectives: The objectives of this study were to analyze deaths after gestational trophoblastic neoplasia and to determine the factors of treatment failure. Methods: This is a retrospective study in Aristide Le Dantec teaching Hospital in Dakar, Senegal, between 1 January 2006 and 31 December 2014. We took into account socio-epidemiological characteristics of patients, initial diagnosis, time between uterine evacuation and admission, time to onset of gestational trophoblastic neoplasia (GTN), treatment received (deadlines, protocols), difficulties experienced in the diagnosis and the initiation of treatment and survival. Results: In total, 1044 patients were admitted during the study period; 164 cases of GTN were diagnosed (15.7%); and 21 deaths occurred leading to a specific lethality of 12.8%. The average age was 30 years. Almost all patients (n = 18; 85.7%) had low income or no income. Eight out of 21 patients (38.1%) were seen in our department after GTN onset. The mean time to onset of GTN of all patients was 22.1 weeks. For 66.6%, histology was not available; the diagnosis of hydatidiform mole was made on the clinical history and sonographic features and GTN on human chorionic gonadotrophin (hCG) evolution and ultrasound findings. None of the patients had regular chemotherapy due to financial reasons. Patients who died within 3 months after diagnosis had metastatic tumors (7 of 21). All these women had resistance to treatment or progressed after three courses of chemotherapy. Ten of the 12 women with high-risk GTN were not treated with multi-agent chemotherapy (EMA-CO) for purely financial reasons. Conclusion and Global Health Implications: The high incidence and mortality require a profound reorganization of our health system and a high awareness of practitioners to refer to time or to declare all suspected cases of hydatidiform mole or gestational trophoblastic neoplasia. PMID:27622010

  4. Heat-flow and subsurface temperature history at the site of Saraya (eastern Senegal)

    NASA Astrophysics Data System (ADS)

    Lucazeau, F.; Rolandone, F.

    2012-06-01

    New temperature measurements from eight boreholes in the West African Craton (WAC) reveal superficial perturbations down to 100 meters below the alteration zone. These perturbations are both related to a recent increase of the surface air temperature (SAT) and to the site effects caused by fluids circulations and/or the lower conduction in the alterites. The ground surface temperature (GST) inverted from the boreholes temperatures is stable in the past (1700-1940) and then dramatically increases in the most recent years (1.5 °C since 1950). This is consistent with the increase of the SAT recorded at two nearby meteorological stations (Tambacounda and Kedougou), and more generally in the Sahel with a coeval rainfall decrease. Site effects are superimposed to the climatic effect and interpreted by advective (circulation of fluids) or conductive (lower conductivity of laterite and of high-porosity sand) perturbations. We used a 1-D finite differences thermal model and a Monte-Carlo procedure to find the best estimates of these sites perturbations: all the eight boreholes temperatures logs can be interpreted with the same basal heat-flow and the same surface temperature history, but with some realistic changes of thermal conductivity and/or fluid velocity. The GST trend observed in Senegal can be confirmed by two previous boreholes measurements made in 1983 in other locations of West Africa, the first one in an arid zone of northern Mali and the second one in a subhumid zone in southern Mali. Finally, the background heat-flow is low (30 ± 1 m Wm-2), which makes this part of the WAC more similar with the observations in the southern part (33 ± 8 m Wm-2) rather than with those in the northern part and in the PanAfrican domains where the surface heat-flow is 15-20 m Wm-2 higher.

  5. Heat-flow and subsurface temperature history at the site of Saraya (eastern Senegal)

    NASA Astrophysics Data System (ADS)

    Lucazeau, F.; Rolandone, F.

    2012-08-01

    New temperature measurements from eight boreholes in the West African Craton (WAC) reveal superficial perturbations down to 100 m below the alteration zone. These perturbations are both related to a recent increase in the surface air temperature (SAT) and to the site effects caused by fluid circulations and/or the lower conduction in the alterites. The ground surface temperature (GST), inverted from the boreholes temperatures, increased slowly in the past (~0.4 °C from 1700 to 1940) and then, more importantly, in recent years (~1.5 °C from 1940 to 2010). This recent trend is consistent with the increase of the SAT recorded at two nearby meteorological stations (Tambacounda and Kedougou), and more generally in the Sahel with a coeval rainfall decrease. Site effects are superimposed to the climatic effect and interpreted by advective (circulation of fluids) or conductive (lower conductivity of laterite and of high-porosity sand) perturbations. We used a 1-D finite differences thermal model and a Monte-Carlo procedure to find the best estimates of these site perturbations: all the eight borehole temperature logs can be interpreted with the same basal heat-flow and the same surface temperature history, but with some realistic changes of thermal conductivity and/or fluid velocity. The GST trend observed in Senegal can be confirmed by two previous borehole measurements made in 1983 in other locations of West Africa, the first one in an arid zone of northern Mali and the second one in a sub-humid zone in southern Mali. Finally, the background heat-flow is low (31±2 mW m-2), which makes this part of the WAC more similar with the observations in the southern part (33±8 mW m-2) rather than with those in the northern part and in the Pan-African domains where the surface heat-flow is 15-20 mW m-2 higher.

  6. Groundwater salinization in the Saloum (Senegal) delta aquifer: minor elements and isotopic indicators.

    PubMed

    Faye, Serigne; Maloszewski, Piotr; Stichler, Willibald; Trimborn, Peter; Cissé Faye, Seynabou; Bécaye Gaye, Cheikh

    2005-05-01

    The hydrochemistry of minor elements bromide (Br), boron (B), strontium (Sr), environmental stable isotopes (18O and 2H) together with major-ion chemistry (chloride, sodium, calcium) has been used to constrain the source(s), relative age, and processes of salinization in the Continental Terminal (CT) aquifer in the Saloum (mid-west Senegal) region. Seventy-one groundwater wells which include 24 wells contaminated by saltwater and three sites along the hypersaline Saloum River were sampled to obtain additional information on the hydrochemical characteristics of the groundwater defined in previous studies. Use of Br against Cl confirms the Saloum River saline water intrusion up to a contribution of 7% into the aquifer. In addition to this recent intrusion, a relatively ancient intrusion of the Saloum River water which had reached at least as far as 20 km south from the source was evidenced. The high molar ratio values of Sr/Cl and Sr/Ca indicate an additional input of strontium presumably derived from carbonate precipitation/dissolution reactions and also via adsorption reactions. The variable B concentrations (7-650 microg/L) found in the groundwater samples were tested against the binary mixing model to evaluate the processes of salinization which are responsible for the investigated system. Sorption of B and depletion of Na occur as the Saloum river water intrudes the aquifer (salinization) in the northern part of the region, whereas B desorption and Na enrichment occur as the fresh groundwater flushing displaces the saline waters in the coastal strip (refreshening). In the central zone where ancient intrusion prevailed, the process of freshening of the saline groundwater is indicated by the changes in major-ion chemistry as well as B desorption and Na enrichment. In addition to these processes, stable isotopes reveal that mixing with recently infiltrating waters and evaporation contribute to the changes in isotopic signature. PMID:15862849

  7. Impact of salinity on early life history traits of three estuarine fish species in Senegal

    NASA Astrophysics Data System (ADS)

    Labonne, Maylis; Morize, Eric; Scolan, Pierre; Lae, Raymond; Dabas, Eric; Bohn, Marcel

    2009-05-01

    The adaptive mechanisms on the early life stages of fishes to hypersaline stress are still poorly understood and probably determine the resistance of a population to disruption, compared with other less plastic species. The Casamance River in Senegal is an ideal location to test the adaptation to salinity as a dam was built in 1998 to exclude saline water intrusion. This lowered the salinity from 70 to 5 upstream and 60 downstream. The salinity influence on the growth in the early life of three West African fish species ( Ethmalosa fimbriata, Sarotherodon melanotheron, and Tilapia guineensis) was studied using the width of microstructures in the otoliths and the individual migratory behaviour analysed from strontium (Sr) to calcium (Ca) ratios in the otoliths. The Sr:Ca ratio was quantified along individual transects measured from the posterior edge of the otolith to the core. The fishes were sampled on both sides of the dam that separated water with low salinity upstream from metahaline and hyperhaline water downstream. The results showed that salinity has different influence on the growth of each species. Ethmalosa fimbriata has the highest growth during the first 180 days in the freshwaters, indicating growth inhibition in the hyperhaline areas. For the two other species no growth difference were found. The Sr/Ca ratio varied widely, in Tilapia and Sarotherodon from below the dam. Individual life histories were more heterogeneous than upstream and showed a crossing of the dam for some individuals which could reach half of the fishes analysed. On the contrary in E. fimbriata, despite the large range of salinity, identical Sr/Ca profiles were found both upstream and downstream. This indicated that Sr/Ca ratio was not appropriate to evaluate life history patterns linked to salinity for this specie.

  8. Rewriting abortion: deploying medical records in jurisdictional negotiation over a forbidden practice in Senegal

    PubMed Central

    Suh, Siri

    2014-01-01

    Boundary work refers to the strategies deployed by professionals in the arenas of the public, the law and the workplace to define and defend jurisdictional authority. Little attention has been directed to the role of documents in negotiating professional claims. While boundary work over induced abortion has been extensively documented, few studies have examined jurisdictional disputes over the treatment of abortion complications, or post-abortion care (PAC). This study explores how medical providers deploy medical records in boundary work over the treatment of complications of spontaneous and induced abortion in Senegal, where induced abortion is prohibited under any circumstance. Findings are based on an institutional ethnography of Senegal’s national PAC program over a period of 13 months between 2010 and 2011. Data collection methods included in-depth interviews with 36 health care professionals, observation of PAC services at three hospitals, a review of abortion records at each hospital, and a case review of illegal abortions prosecuted by the state. Findings show that health providers produce a particular account of the type of abortion treated through a series of practices such as the patient interview and the clinical exam. Providers obscure induced abortion in medical documents in three ways: the use of terminology that does not differentiate between induced and spontaneous abortion in PAC registers, the omission of data on the type of abortion altogether in PAC registers, and reporting the total number but not the type of abortions treated in hospital data transmitted to state health authorities. The obscuration of suspected induced abortion in the record permits providers to circumvent police inquiry at the hospital. PAC has been implemented in nearly 50 countries worldwide. This study demonstrates the need for additional research on how medical professionals negotiate conflicting medical and legal obligations in the daily practice of treating abortion

  9. Quantifying the impact of land degradation on crop production: the case of Senegal

    NASA Astrophysics Data System (ADS)

    Sonneveld, B. G. J. S.; Keyzer, M. A.; Ndiaye, D.

    2015-06-01

    Land degradation has been a persistent problem in Senegal for a long time and by now has become a serious impediment to long term development. In this paper, we quantify the impact of land degradation on crop yields using the results of a nation-wide land degradation assessment. For this, the study needs to address two issues. First, the land degradation assessment comprises qualitative expert judgments that have to be converted into more objective, quantitative terms. We propose a land degradation index and assess its plausibility. Second, observational data on soils, land use and rainfall do not provide sufficient information to isolate the impact of land degradation. We, therefore, design a pseudo-experiment that for sites with otherwise similar circumstances compares the yield of a site with and one without land degradation. This pairing exercise is conducted under a gradual refining of the classification of circumstances, until a more or less stable response to land degradation is obtained, In this way, we hope to have controlled sufficiently for confounding variables that will bias the estimation of the impact of land degradation on crop yields. A small number of shared characteristics reveal tendencies of "severe" land degradation levels being associated with declining yields as compared to similar sites with "low" degradation levels. However, as we zoom in at more detail some exceptions come to the fore, in particular in areas without fertilizer application. Yet, our overall conclusion is that yield reduction is associated to higher levels of land degradation, irrespective of whether fertilizer is being applied or not.

  10. Late Holocene interdecadal climate variability in the Sahel: inferences from a marine dust record offshore Senegal

    NASA Astrophysics Data System (ADS)

    Meyer, I.; Stuut, J.-B.; Mollenhauer, G.; Mulitza, S.; Zabel, M.

    2009-04-01

    Present-day climate in northwestern Africa strongly depends on the avaiability of water. At least since the Pliocene the Saharan Desert and the semiarid Sahel belt (tropical North Afrika) have been frequently affected by sudden shifts to more arid climate. The rate of change from arid to humid conditions is presently under heavy debate (e.g., deMenocal et al., 2001, Kröpelin et al., 2008). A recent example of abrupt droughts occurred in the early 70's and 80's of the last century. In this study we compare different high-resolution marine sediment records of Sahel climate variability from the Senegal mud belt, northwest Africa. Marine sediment cores show the variations of terrigenous input (both aeolian dust and fluvial matter) from the African continent. Due to their different distinctive grain-size distributions, aeolian dust and fluvial mud can be recognised and quantified in marine sediments (e.g., Stuut et al., 2002). Based on these variations in the grain-size distributions of the terrigenous sediment fraction, deconvolved with an end-member modelling algorithm (Weltje, 1997), are used to reconstruct rainfall variability and dust production on land for the last 4,000 years. References P. B. deMenocal, et al. (2001). Late Holocene Cultural Responses to Climate Change During the Holocene. Science 292, 667 S. Kröpelin, et al. (2008) Response to Comment on "Climate-Driven Ecosystem Succession in the Sahara: The Past 6000 Years" Science 322, 1326c G. J. Weltje (1997) End-member modeling of compositional data: Numerical-statistical algorithms for solving the explicit mixing problem. Mathematical Geology 9, 4

  11. Dyslipidemia, obesity and other cardiovascular risk factors in the adult population in Senegal

    PubMed Central

    Doupa, Dominique; Seck, Sidy Mohamed; Dia, Charles Abdou; Diallo, Fatou Agne; Kane, Modou Oumy; Kane, Adama; Gueye, Pape Madieye; Mbaye, Maimouna Ndour; Gueye, Lamine; Jobe, Modou

    2014-01-01

    Introduction According to the WHO, 50% of deaths worldwide (40.1% in developing countries) are due to chronic non-communicable diseases (NCDs). Of these chronic NCDs, cardiovascular diseases remain the leading cause of death and disability in developed countries. The Framingham study has shown the importance of hypercholesterolemia as a primary risk factor. In Senegal, the epidemiology of dyslipidemia and obesity are still poorly understood due to the lack of comprehensive studies on their impact on the general population. This motivated this study to look into the key epidemiologic and socio-demographic determinants of these risk factors. Methods It was a cross-sectional descriptive epidemiological survey which included 1037 individuals selected by cluster sampling. Data were collected using a questionnaire following the WHO STEPwise approach. Socio-demographic, health and biomedical variables were collected. P value <0.05 was considered to be statistically significant. Results The average age was 48 years with a female predominance (M: F of 0.6). The literacy rate was 65.2% and 44.7% of participants were from rural areas. The prevalence of hypercholesterolemia, hyperLDLemia, hypoHDLemia, hypertriglyceridemia and mixed hyperlipidemia were 56%, 22.5%, 12.4%, 7.11% and 1.9% respectively. One in four was obese (BMI> 30kg/m2) and 34.8% had abdominal obesity. The main factors significantly associated with dyslipidemia were obesity, urban dwelling, physical inactivity and a family history of dyslipidemia. Conclusion The prevalence of dyslipidemia, obesity and other risk factors in the population was high needing immediate care for those affected and implementation of prevention strategies. PMID:25815102

  12. Quantifying the impact of land degradation on crop production: the case of Senegal

    NASA Astrophysics Data System (ADS)

    Sonneveld, B. G. J. S.; Keyzer, M. A.; Ndiaye, D.

    2016-01-01

    Land degradation has been a persistent problem in Senegal for more than a century and by now has become a serious impediment to long-term development. In this paper, we quantify the impact of land degradation on crop yields using the results of a nationwide land degradation assessment. For this, the study needs to address two issues. First, the land degradation assessment comprises qualitative expert judgements that have to be converted into more objective, quantitative terms. We propose a land degradation index and assess its plausibility. Second, observational data on soils, land use, and rainfall do not provide sufficient information to isolate the impact of land degradation. We, therefore, design a pseudo-experiment that for sites with otherwise similar circumstances compares the yield of a site with and one without land degradation. This pairing exercise is conducted under a gradual refining of the classification of circumstances, until a more or less stable response to land degradation is obtained. In this way, we hope to have controlled sufficiently for confounding variables that will bias the estimation of the impact of land degradation on crop yields. A small number of shared characteristics reveal tendencies of "severe" land degradation levels being associated with declining yields as compared to similar sites with "low" degradation levels. However, as we zoom in at more detail some exceptions come to the fore, in particular in areas without fertilizer application. Yet, our overall conclusion is that yield reduction is associated with higher levels of land degradation, irrespective of whether fertilizer is being applied or not.

  13. Infant and early childhood mortality in the Sine-Saloum region of Senegal.

    PubMed

    Goldberg, H I; M'Bodji, F G

    1988-10-01

    Infant and early childhood mortality in Senegal's Sine-Saloum region was investigated through use o f data from a 1982-83 family health survey. The survey involved interviews with 1894 married women 15-44 years of age living in extended family residential units in rural areas. Given evidence of substantial underreporting of early deaths, at least among children born before 1980, an adjustment factor was applied to the survey data. Infant mortality was estimated to be about 113/1000 live births and mortality before age 5 years was 263/1000. Strong mortality differentials, particularly after infancy, were noted according to the 2 socioeconomic variables included in the analysis: type of house and father's occupation. The probability of dying at ages 1-4 years was 50% higher among children living in traditional homes than among those in modern homes as well as among children whose fathers' were engaged in primary sector occupations (farming, livestock, fishing). Infant mortality showed no sex differential, while mortality at ages 1-4 years was 18% higher among females. Diarrheal and respiratory diseases were the 2 leading causes of death, killing at least 15% of all children by 5 years of age. Tetanus was an important cause of death during infancy, while measles and malaria were significant causes only after the 1st birthday. For all causes of death, the effect of socioeconomic status is higher in early childhood than in infancy, presumably because of the protective effect of breastfeeding. 82% of children who died had fever during their terminal illness, 51% had diarrhea, 39% had a cough, and 14% a rash. At least some mortality in this area might be prevented through treatment of these symptoms. However, calculating the degree to which particular interventions such as oral rehydration for diarrhea would reduce mortality is a complex task, requiring knowledge of replacement mortality, effectiveness of interventions, and the numbers of mothers who would utilize them

  14. Crop Monitoring as a Tool for Modelling the Genesis of Millet Prices in Senegal

    NASA Astrophysics Data System (ADS)

    Jacques, D.; Marinho, E.; Defourny, P.; Waldner, F.; d'Andrimont, R.

    2015-12-01

    Food security in Sahelian countries strongly relies on the ability of markets to transfer staplesfrom surplus to deficit areas. Market failures, leading to the inefficient geographical allocation of food,are expected to emerge from high transportation costs and information asymmetries that are commonin moderately developed countries. As a result, important price differentials are observed betweenproducing and consuming areas which damages both poor producers and food insecure consumers. Itis then vital for policy makers to understand how the prices of agricultural commodities are formed byaccounting for the existing market imperfections in addition to local demand and supply considerations. To address this issue, we have gathered an unique and diversified set of data for Senegal andintegrated it in a spatially explicit model that simulates the functioning of agricultural markets, that isfully consistent with the economic theory. Our departure point is a local demand and supply modelaround each market having its catchment areas determined by the road network. We estimate the localsupply of agricultural commodities from satellite imagery while the demand is assumed to be a functionof the population living in the area. From this point on, profitable transactions between areas with lowprices to areas with high prices are simulated for different levels of per kilometer transportation costand information flows (derived from call details records i.e. mobile phone data). The simulated prices are then comparedwith the actual millet prices. Despite the parsimony of the model that estimates only two parameters, i.e. the per kilometertransportation cost and the information asymmetry resulting from low levels of mobile phone activitybetween markets, it impressively explains more than 80% of the price differentials observed in the 40markets included in the analysis. In one hand these results can be used in the assessment of the socialwelfare impacts of the further development of

  15. Herbivorous and microbial grazing pathways of metazooplankton in the Senegal River Estuary (West Africa)

    NASA Astrophysics Data System (ADS)

    Pagano, Marc; Champalbert, Gisèle; Aka, Maryse; Kouassi, Ernest; Arfi, Robert; Got, Patrice; Troussellier, Marc; N'Dour, E. H.; Corbin, Daniel; Bouvy, Marc

    2006-04-01

    The trophic relationships between metazooplankton and natural particles were studied in May 2002 in the Senegal River Estuary (16°N, 16°W) in low water conditions (dry season). Environmental factors, micro-organism and metazooplankton were analyzed through sampling at a fixed station. Gut fluorescence measurements of and field experiments on zooplankton metabolism were also performed. Chlorophyll a concentrations ranged from 6.5 to 10.2 μg l -1. The phytoplankton was dominated by picoplanktonic cells (83-94% of total numbers). The particulate organic carbon (1.2-2.7 mg l -1) originated for a large amount from organic detritus (20-70%). The zooplankton biomass was dominated by Cirripedia larvae and calanoid copepods ( Acartia clausi, Temora stylifera and Paracalanus spp.). These taxa showed diel vertical migrations and maximal gut fluorescence at night, independently of tidal effects. Metabolic budgets show that their daily ingestion rates on phytoplankton (27-55% of body carbon weight) were insufficient to balance their respiration needs (40-51% of body carbon) and suggest that a selective feeding upon micro-heterotrophs (Heterotrophic NanoFlagellates, HNF) and/or detritus would be necessary to complete their energetic needs. The daily grazing pressure of metazooplankton represented only 5% of the in situ chlorophyll a and 14% of the primary production, but this pressure was mainly orientated towards nanophytoplankton. The daily recycling of nutrients by the metazooplankton excretion was rather high (83 and 46% of the in situ NH 4-N and PO 4-P concentrations, respectively). Therefore, the impact of metazooplankton on phytoplankton through top-down (grazing) and bottom-up (nutrient recycling) processes seemed substantial in this tropical estuary.

  16. Plant-food and tool transfer among savanna chimpanzees at Fongoli, Senegal.

    PubMed

    Pruetz, Jill D; Lindshield, Stacy

    2012-04-01

    Transferring food is considered a defining characteristic of humans, as such behavior is relatively uncommon in other animal species save for kin-based transfer. Chimpanzees (Pan troglodytes) are one exception, as they commonly transfer meat among nonrelatives but rarely transfer other resources. New observations at Fongoli, Senegal, show habitual transfer of wild-plant foods and other non-meat resources among community members beyond transfers from mother to offspring. We explore various explanations for these behaviors with a focus on age- and sex-class patterns in transfer events. In a total of 27 of 41 cases, male chimpanzees at Fongoli transferred wild-plant foods or tools to females. Most other cases involved transfer among males or males taking food from females. In light of male-female transfer patterns at Fongoli, we examine four hypotheses that have been applied to food transfer in apes: (1) testing for male-coercive tendency (van Noordwijk and van Schaik, Behav Ecol Sociobiol 63:883-890, 2009), (2) costly signaling (Hockings et al. PLoS ONE 2:e886, 2007), (3) food-for-sex (Gomes and Boesch, PLoS ONE 4:5116, 2009), and (4) sharing-under-pressure (Gilby, Anim Behav 71:953-963, 2006). We also consider hypotheses posed to explain transfer among callitrichids, where such behavior is more common (Ruiz-Miranda et al. Am J Primatol 48:305-320, 1999). Finally, we examine variables such as patch and food size and food transport. We discuss our findings relative to general patterns of non-meat transfer in Pan and examine them in the context of chimpanzee sociality in particular. We then contrast chimpanzee species and subspecies in terms of non-meat food and tool transfer and address the possibility that a savanna environment contributes to the unusual pattern observed at Fongoli. PMID:22101639

  17. Assessing Drivers of Full Adoption of Test and Treat policy for Malaria in Senegal

    PubMed Central

    Faust, Christina; Zelner, Jonathan; Brasseur, Philippe; Vaillant, Michel; Badiane, Malick; Cisse, Moustafa; Grenfell, Bryan; Olliaro, Piero

    2015-01-01

    Malaria treatment policy has changed from presumptive treatment to targeted “test and treat” (T&T) with malaria rapid diagnostic tests (RDTs) and artemisinin combination therapy (ACT). This transition involves changing behavior among health providers, meaning delays between introduction and full implementation are recorded in almost every instance. We investigated factors affecting successful transition, and suggest approaches for accelerating uptake of T&T. Records from 2000 to 2011 from health clinics in Senegal where malaria is mesoendemic were examined (96,166 cases). The study period encompassed the implementation of national T&T policy in 2006. Analysis showed that adherence to test results is the first indicator of T&T adoption and is dependent on accumulation of experience with positive RDTs (odds ratio [OR]: 0.55 [P ≤ 0.001], 95% confidence interval [CI]: 0.53–0.58). Reliance on tests for malaria diagnosis (rather than presumptive diagnosis) followed after test adherence is achieved, and was also associated with increased experience with positive RDTs (OR: 0.60 [P ≤ 0.001], 95% CI: 0.58–0.62). Logistic models suggest that full adoption of T&T clinical practices can occur within 2 years, that monitoring these behavioral responses rather than RDT or ACT consumption will improve evaluation of T&T uptake, and that accelerating T&T uptake by focusing training on adherence to test results will reduce overdiagnosis and associated health and economic costs in mesoendemic regions. PMID:25962776

  18. Moving malaria in pregnancy programs from neglect to priority: experience from Malawi, Senegal, and Zambia

    PubMed Central

    Roman, Elaine; Wallon, Michelle; Brieger, William; Dickerson, Aimee; Rawlins, Barbara; Agarwal, Koki

    2014-01-01

    Background: Pregnant women and infants are particularly vulnerable to malaria. National malaria in pregnancy (MIP) programs in Malawi, Senegal, and Zambia were reviewed to identify promising strategies that have helped these countries achieve relatively high coverage of MIP interventions as well as ongoing challenges that have inhibited further progress. Methods: We used a systematic case study methodology to assess health system strengths and challenges in the 3 countries, including desk reviews of available reports and literature and key informant interviews with national stakeholders. Data were collected between 2009 and 2011 and analyzed across 8 MIP health systems components: (1) integration of programs and services, (2) policy, (3) commodities, (4) quality assurance, (5) capacity building, (6) community involvement, (7) monitoring and evaluation, and (8) financing. Within each program area, we ranked degree of scale up across 4 stages and synthesized the findings in a MIP table of analysis to reveal common themes related to better practices, remaining bottlenecks, and opportunities to accelerate MIP coverage, strengthen MIP programs, and improve results. Findings: Each of the 3 countries has malaria policies in place that reflect current MIP guidance from the World Health Organization. The 3 countries successfully integrated MIP interventions into a platform of antenatal care services, but coordination at the national level was disjointed. All 3 countries recognized the importance of having a MIP focal person to ensure collaboration and planning at the national level, but only Malawi had appointed one. Commodity stockouts were frequent due to problems at all levels of the logistics system, from quantification to distribution. Lack of support for quality assurance and weak monitoring and evaluation mechanisms across all 3 countries affected optimal coverage. Conclusions: MIP programs should address all 8 interconnected MIP health systems areas holistically, in

  19. Au20: A Tetrahedral Cluster

    SciTech Connect

    Li, Jun; Li, Xi; Zhai, Hua Jin; Wang, Lai S.

    2003-02-07

    Photoelectron spectroscopy revealed that a 20 atom gold cluster has an extremely large energy gap, which is even greater than that of C60, and an electron affinity comparable with that of C60. This observation suggests that the Au20 cluster must be extremely stable and chemically inert. Using relativistic density functional calculations, we found that Au20 possesses a remarkable tetrahedral structure, which is a fragment of the bulk face-centered cubic lattice of gold with a small structural relaxation. Au20 is thus a true cluster molecule, while at the same time it is exactly part of the bulk, but with very different properties. The tetrahedral Au20 may possess interesting catalytic properties and may be synthesized in bulk quantity or assembled on non-interacting surfaces.

  20. Situation Report--Ghana, Guyana, India, Japan, Kenya, Khmer Republic, Nepal, Niger, Republic of Vietnam, Senegal, Thailand, and Trinidad and Tobago.

    ERIC Educational Resources Information Center

    International Planned Parenthood Federation, London (England).

    Data relating to population and family planning in twelve foreign countries are presented in these situation reports. Countries included are Ghana, Guyana, India, Japan, Kenya, Khmer Republic, Nepal, Niger, Republic of Vietnam, Senegal, Thailand, and Trinidad and Tobago. Information is provided under two topics, general background and family…

  1. Development of a Model for Estimation of Acacia Senegal Tree Biomass Using Allometry and Aster Satellite Imagery at Ennuhud, West Kordofan State, Sudan

    NASA Astrophysics Data System (ADS)

    Elamin, Hatim; Elnour Adam, Hassan; Csaplovics, Elmar

    The current paper deals with the development of a biomass model for Acacia senegal trees by applying allometric equations for ground data combined with ASTER satellite data sets. The current study is conducted around Ennuhud area which is located in Ennuhud locality in West Kordofan State, Sudan. Primary data are obtained by application of random sampling around Ennuhud town where Acacia senegal tree species is abundant. Ten sample units are taken. Each unit contains five sample plots (15x15 m), one in the centre and the others in the four directions 100 m away from the centre forming a total of 50 sample plots. The tree coordinates, diameter/diameters (diameter at breast height ≥ 5 cm), height and crown diameters will be recorded. Sensor data were acquired from ASTER remote sensing satellite (29.03.2007 & 26.01.2011) and integrated with the in-situ data. The expected findings allow for the calculation of the mean diameter of trees. The tree above ground biomass (TAGB), tree below ground biomass (TBGB) and the tree total biomass (TTB) of Acacia senegal are computed consequently. Remotely sensed data are integrated with the ground data for creating the data base for calculating the correlation of the relationship between the two methods of data collection. The application of allometric equations is useful as a non-destructive method for biomass estimation by the application of remote sensing is recommended for biomass modelling over large areas. Keywords: Biomass model, Acacia senegal tree, remote sensing, Ennuhud, North Kordofan

  2. Recalibrating Baseline Evidence in Burundi, Malawi, Senegal and Uganda: Exploring the Potential of Multi-Site, National-Level Stakeholder Engagement in Participatory Evaluation

    ERIC Educational Resources Information Center

    Edge, Karen; Marphatia, Akanksha A.

    2015-01-01

    This paper details our collaborative work on the Improving Learning Outcomes in Primary Schools (ILOPS) project in Burundi, Malawi, Uganda and Senegal. ILOPS set out to establish an innovative template for multi-stakeholder, multinational participatory evaluation (PE) and examine the fundamental roles, relationships and evidence that underpin the…

  3. [Oral benefits for the elderly: results of a one-year implementation of the "Sesame" plan in Senegal].

    PubMed

    Cisse, D; Lo, C M; Faye, D; Diouf, M; Kanoute, A; Kane, A W

    2010-03-01

    Among the 650,000 persons aged 60 and over in Senegal, only 30% were receiving social security coverage, divided between the Senegalese Retirement Providence Institute and the National Retirement Fund. To fill the social demand, the government has put in place since 1 September 2006 a plan called "Sesame" which gives people aged 60 and older, free access to certain health services provided in public health. The implementation of this plan creates a lot of comments in the health community. The objectives of this study were to describe the dental benefits offered and to identify the difficulties perceived and experienced by the service provider after one year the "sesame" plan was implemented in Ouakam Health Center dental office, benchmark place of Gerontology in the Dakar North health district in Senegal. The study included two components: quantitative and qualitative terms, respectively, consisting of a retrospective study from sheets review and an interview with the health center service provider. The beneficiaries were a total of 42, mean age 68 years, including 66.7% men. Just over a third (35.7%) resided outside Ouakam. Almost 4/5 of the beneficiaries have suffered dental extractions on 1 to 10 teeth per beneficiary. The proportions of people receiving dentine treatment and curetage were respectively 4.8% and 2.4%. Qualitative data showed that the implementation of the plan was not shared between providers and beneficiaries. The "Sesame" plan is a commendable initiative to encourage and improve. PMID:20839478

  4. HIV type 1 subtype C remains the predominant subtype in men having sex with men in Senegal.

    PubMed

    Ndiaye, Halimatou Diop; Tchiakpe, Edmond; Vidal, Nicole; Ndiaye, Ousseynou; Diop, Abdou Khoudia; Peeters, Martine; Mboup, Souleymane; Toure-Kane, Coumba

    2013-09-01

    HIV-1 epidemics are expanding among men who have sex with men in low- and middle-income countries. To confirm and further explore preliminary data in Senegal, we aimed to determine 3 years after a first study the HIV-1 genetic diversity in three different viral regions. From 109 samples available in 2007, 93 were sequenced in gag, 77 in env, and 60 in pol. Phylogenetic analysis showed that subtype C predominated (38-52%), followed by CRF02_AG (30-40%), subtype B (13-17%), and CRF09_cpx (2.6-5%). Subsubtype A3 and strains tightly linked to CRF43_02G were identified in env and gag, respectively, and 12% of the samples were unique recombinants. Six transmission chains involving two to seven individuals were identified. Some strains carried resistance mutations inside transmission chains. This study confirmed the existence of a dual epidemic in Senegal and emphasized the need to strengthen prevention programs to avoid strains intermixing between low-risk women and high-risk men. PMID:23742654

  5. First insights into the genetic diversity and origin of Leishmania infantum in Mont Rolland (Thiès region, Senegal).

    PubMed

    Cassan, Cecile; Dione, Michel Mainack; Dereure, Jacques; Diedhiou, Souleymane; Bucheton, Bruno; Hide, Mallorie; Kako, Caroline; Gaye, Oumar; Senghor, Massila; Niang, Abdoul Aziz; Bañuls, Anne-Laure; Faye, Babacar

    2016-06-01

    Visceral leishmaniasis is not endemic in West Africa. However, high seroprevalence of Leishmania infantum infection (one of the Leishmania species that cause visceral leishmaniasis) was detected in dogs and humans in the Mont Rolland community (close to Thiès, Senegal), despite the lack of reports concerning human clinical cases. Our aim was to genetically characterize this L. infantum population and identify its origin. We thus conducted seven field surveys in 25 villages of the Mont Rolland community between 2005 and 2009 and blood samples were collected from 205 dogs. Serological testing indicated that 92 dogs (44.9%) were positive for Leishmania infection. L. infantum was identified as the cause of infection. Analysis of 29 L. infantum isolates from these dogs by multilocus microsatellite typing and multilocus sequence typing indicated that this population had very limited genetic diversity, low level of heterozygosity and only seven different genotypes (79.3% of all isolates had the same genotype). Multilocus sequence typing showed that the Mont Rolland isolates clustered with strains from the Mediterranean basin and were separated from East African and Asian strains. Therefore, our data suggest a quite recent and unique introduction into Senegal of a L. infantum strain from the Mediterranean basin. PMID:26945844

  6. Parasitic Infections among Children under Five Years in Senegal: Prevalence and Effect on Anaemia and Nutritional Status

    PubMed Central

    Tine, Roger C. K.; Faye, Babacar; Ndour, Cheikh T.; Sylla, Khadime; Sow, Doudou; Ndiaye, Magatte; Ndiaye, Jean L.; Magnussen, Pascal; Alifrangis, Michael; Bygbjerg, Ib C.; Gaye, Oumar

    2013-01-01

    Although malaria is declining in many countries in Africa, malaria and anaemia remain frequent in children. This study was conducted to assess the relationship between malaria parasitaemia, intestinal worms, and anaemia, in children <5 years living in low transmission area in Senegal. A survey was carried out in 30 villages in the central part of Senegal. A two-level random cluster sampling technique was used to select study participant. Children <5 years were enrolled after informed consent. For each child, blood thick and smear tests were performed, haemoglobin concentration was measured with HemoCue, and stool samples were collected and examined using the Ritchie technique. A total of 736 children were recruited. Malaria parasite prevalence was 1.5% (0.7–2.6); anaemia was found in 53.4% (48.2–58.9), while intestinal parasites and stunting represented 26.2% (22.6–30.2) and 22% (18.6–25.5), respectively. In a logistic regression analysis, anaemia was significantly associated with malaria parasitaemia (aOR= 6.3 (1.5–53.5)) and stunting (aOR = 2 (1.2–3.1)); no association was found between intestinal parasites and anaemia. Malaria and anaemia remain closely associated even when malaria is declining. Scaling up antimalarial interventions may contribute to eliminate malaria and reduce the occurrence of anaemia among children. PMID:27335851

  7. Preliminary report of an identification mission for safe motherhood, Senegal: putting the M back in M.C.H.

    PubMed

    Kimball, A M; Cisse, S; Fayemi, G; Ericcson, S; Helfenbein, S; Nakoulima, A; Sene, N T; Papiernik, E

    1988-04-01

    The Government of Senegal, in keeping with the priority given to women and children in its health programs, requested the assistance of the United Nations Development Program (UNDP) in identifying and executing a program to diminish maternal mortality in that country. A UNDP "Mission of Identification" was carried out in response to this initiative. The preliminary results of this mission confirm that the issue of maternal safety is of primary concern not only to the government but also to women in the Republic of Senegal. The methodology employed during this mission allowed the team of national and international experts to confirm the level of this concern and to identify four major potential areas of intervention. Quantitative goals for the program have been set and estimates for the efficacy of each of the intervention areas indicate that intervention through the timely provision of access to emergency surgical services and appropriate prenatal care will yield the largest reduction. The feasibility of providing interventions in each of the four areas was also addressed during the mission. This methodology will be applicable to other settings as Third World countries begin to address the problem of excessive maternal mortality. PMID:2898392

  8. Prevalence and intensity of urinary schistosomiasis among school children in the district of Niakhar, region of Fatick, Senegal

    PubMed Central

    2014-01-01

    Background Urinary schistosomiasis is a parasitic disease that exists in all regions of Senegal. It is a major public health issue in this country. This study was carried out to determine the prevalence and intensity of this parasitosis in 12 villages of Niakhar (Fatick, Senegal). Methods A total of 210 schoolchildren, aged 7 to 15 years, were enrolled in this study, and urine samples were examined for Schistosoma haematobium eggs using a standard urine filtration technique. Results Of these children, 121 (57.6%) were found to be infected with a mean geometric count of 185 eggs per 10 ml of urine. The disease was present in all surveyed villages, and the prevalence ranged from 14.3% to 92.8%. The prevalence of infection was significantly correlated with increasing age and was higher in boys. Infection intensity was significantly higher in boys but did not significantly differ with age. Significant relationships between i) water contact or access to running water and ii) the prevalence or intensity of urinary schistosomiasis were also noted. Conclusions The district of Niakhar is endemic for urinary schistosomiasis, with a high intensity of infection. A control program to decrease the prevalence and intensity should be implemented in this area to improve community health. PMID:24387599

  9. Geographic variation of female genital mutilation and legal enforcement in sub-Saharan Africa: a case study of Senegal.

    PubMed

    Kandala, Ngianga-Bakwin; Komba, Paul N

    2015-04-01

    This paper draws on household data to examine the prevalence of female genital mutilation (FGM) in Senegal and the effectiveness of the country's anti-FGM law in dealing with actual breaches and providing protection to the victims. The 2010-2011 Senegal Demographic Health Survey and Multiple Indicators Cluster Survey (SDHS-MICS) covers 14,228 women and their daughters. Logistic regression was used to investigate the geographic distribution of FGM across regions. For the enforceability of anti-FGM, desk research was used. Overall prevalence among women and daughters was 28.1% and 6.2%, respectively. Significant factors were sociodemographics, ethnicity, and region. This analysis shows both advantages and vulnerabilities of the anti-FGM law in relation to the issue of enforcement. It indicates that the law falls short of offering adequate protection to potential victims. FGM is a cultural and social norm imbedded predominantly in rural settings and as such, drives resistance to jettisoning FGM. Legislation has been one of the driving forces behind the eradication of the practice. PMID:25732681

  10. Kandia: threatened forest, threatened livelihood - a study of human-environment interaction in the Department of Velingara, Senegal

    USGS Publications Warehouse

    Freudenberger, Karen Schoonmaker; Tappan, Gary

    1997-01-01

    This case study is one of several carried out as part the Long-term Environmental Monitoring in Senegal Project. Co-financed by USAID and the U.S. Geological Survey's EROS Data Center (EDC), and implemented by EDC and the Centre de Suivi Ecologique (CSE), this project has carried out extensive monitoring of natural resources and land use patterns in Senegal in order to better understand the complex dynamics of change in semi-arid tropics. The monitoring, as carried out by EROS staff and their Senegalese collaborators, has involved use of information collected by remote sensing (satellite and aerial photographs) as well as extensive field work including the collection of physical information about soils, vegetation, land use practices, and biodiversity at 2 over 600 sites in all parts of the country (Tappan and Wood, 1995). This information provides a remarkable record of changes in physical and land cover parameters over the last 30 years. Figure 2 presents a satellite image of the eastern Kolda Region covering the Department of Velingara.

  11. Geographic Variation of Female Genital Mutilation and Legal Enforcement in Sub-Saharan Africa: A Case Study of Senegal

    PubMed Central

    Kandala, Ngianga-Bakwin; Komba, Paul N.

    2015-01-01

    This paper draws on household data to examine the prevalence of female genital mutilation (FGM) in Senegal and the effectiveness of the country's anti-FGM law in dealing with actual breaches and providing protection to the victims. The 2010–2011 Senegal Demographic Health Survey and Multiple Indicators Cluster Survey (SDHS-MICS) covers 14,228 women and their daughters. Logistic regression was used to investigate the geographic distribution of FGM across regions. For the enforceability of anti-FGM, desk research was used. Overall prevalence among women and daughters was 28.1% and 6.2%, respectively. Significant factors were sociodemographics, ethnicity, and region. This analysis shows both advantages and vulnerabilities of the anti-FGM law in relation to the issue of enforcement. It indicates that the law falls short of offering adequate protection to potential victims. FGM is a cultural and social norm imbedded predominantly in rural settings and as such, drives resistance to jettisoning FGM. Legislation has been one of the driving forces behind the eradication of the practice. PMID:25732681

  12. Interfacial nanodroplets guided construction of hierarchical Au, Au-Pt, and Au-Pd particles as excellent catalysts

    PubMed Central

    Ma, Aijing; Xu, Jie; Zhang, Xuehua; Zhang, Bin; Wang, Dayang; Xu, Haolan

    2014-01-01

    Interfacial nanodroplets were grafted to the surfaces of self-sacrificed template particles in a galvanic reaction system to assist the construction of 3D Au porous structures. The interfacial nanodroplets were formed via direct adsorption of surfactant-free emulsions onto the particle surfaces. The interfacial nanodroplets discretely distributed at the template particle surfaces and served as soft templates to guide the formation of porous Au structures. The self-variation of footprint sizes of interfacial nanodroplets during Au growth gave rise to a hierarchical pore size distribution of the obtained Au porous particles. This strategy could be easily extended to synthesize bimetal porous particles such as Au-Pt and Au-Pd. The obtained porous Au, Au-Pt, and Au-Pd particles showed excellent catalytic activity in catalytic reduction of 4-nitrophenol. PMID:24797697

  13. Interfacial nanodroplets guided construction of hierarchical Au, Au-Pt, and Au-Pd particles as excellent catalysts.

    PubMed

    Ma, Aijing; Xu, Jie; Zhang, Xuehua; Zhang, Bin; Wang, Dayang; Xu, Haolan

    2014-01-01

    Interfacial nanodroplets were grafted to the surfaces of self-sacrificed template particles in a galvanic reaction system to assist the construction of 3D Au porous structures. The interfacial nanodroplets were formed via direct adsorption of surfactant-free emulsions onto the particle surfaces. The interfacial nanodroplets discretely distributed at the template particle surfaces and served as soft templates to guide the formation of porous Au structures. The self-variation of footprint sizes of interfacial nanodroplets during Au growth gave rise to a hierarchical pore size distribution of the obtained Au porous particles. This strategy could be easily extended to synthesize bimetal porous particles such as Au-Pt and Au-Pd. The obtained porous Au, Au-Pt, and Au-Pd particles showed excellent catalytic activity in catalytic reduction of 4-nitrophenol. PMID:24797697

  14. Geographic information science: Contribution to understanding salt and sodium affected soils in the Senegal River Valley

    NASA Astrophysics Data System (ADS)

    Ndiaye, Ramatoulaye

    The Senegal River valley and delta (SRVD) are affected by long term climate variability. Indicators of these climatic shifts include a rainfall deficit, warmer temperatures, sea level rise, floods, and drought. These shifts have led to environmental degradation, water deficits, and profound effects on human life and activities in the area. Geographic Information Science (GIScience), including satellite-based remote sensing methods offer several advantages over conventional ground-based methods used to map and monitor salt-affected soil (SAS) features. This study was designed to assess the accuracy of information on soil salinization extracted from Landsat satellite imagery. Would available imagery and GIScience data analysis enable an ability to discriminate natural soil salinization from soil sodication and provide an ability to characterize the SAS trend and pattern over 30 years? A set of Landsat MSS (June 1973 and September 1979), Landsat TM (November 1987, April 1994 and November 1999) and ETM+ (May 2001 and March 2003) images have been used to map and monitor salt impacted soil distribution. Supervised classification, unsupervised classification and post-classification change detection methods were used. Supervised classifications of May 2001 and March 2003 images were made in conjunction field data characterizing soil surface chemical characteristics that included exchange sodium percentage (ESP), cation exchange capacity (CEC) and the electrical conductivity (EC). With this supervised information extraction method, the distribution of three different types of SAS (saline, saline-sodic, and sodic) was mapped with an accuracy of 91.07% for 2001 image and 73.21% for 2003 image. Change detection results confirmed a decreasing trend in non-saline and saline soil and an increase in saline-sodic and sodic soil. All seven Landsat images were subjected to the unsupervised classification method which resulted in maps that separate SAS according to their degree of

  15. Symmetry energy from elliptic flow in 197Au + 197Au

    NASA Astrophysics Data System (ADS)

    Russotto, P.; Wu, P. Z.; Zoric, M.; Chartier, M.; Leifels, Y.; Lemmon, R. C.; Li, Q.; Łukasik, J.; Pagano, A.; Pawłowski, P.; Trautmann, W.

    2011-03-01

    The elliptic-flow ratio of neutrons with respect to protons or light complex particles in reactions of neutron-rich systems at relativistic energies is proposed as an observable sensitive to the strength of the symmetry term in the equation of state at supra-normal densities. The results obtained from the existing FOPI/LAND data for 197Au + 197Au collisions at 400 MeV/nucleon in comparison with the UrQMD model favor a moderately soft symmetry term with a density dependence of the potential term proportional to (ρ /ρ0) γ with γ = 0.9 ± 0.4.

  16. Flow in Au+Au collisions at RHIC

    NASA Astrophysics Data System (ADS)

    Belt Tonjes, Marguerite; PHOBOS Collaboration; Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; García, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Holynski, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Tang, J.-L.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wolfs, F. L. H.; Wosiek, B.; Wozniak, K.; Wuosmaa, A. H.; Wyslouch, B.

    2004-08-01

    The study of flow can provide information on the initial state dynamics and the degree of equilibration attained in heavy-ion collisions. This contribution presents results for both elliptic and directed flow as determined from data recorded by the PHOBOS experiment in Au+Au runs at RHIC at \\sqrt{s_{{\\rm NN}}} = 19.6, 130 and 200 GeV. The PHOBOS detector provides a unique coverage in pseudorapidity for measuring flow at RHIC. The systematic dependence of flow on pseudorapidity, transverse momentum, centrality and energy is discussed.

  17. Using Spatial Information Technologies as Monitoring Devices in International Watershed Conservation along the Senegal River Basin of West Africa

    PubMed Central

    Merem, Edmund C.; Twumasi, Yaw A.

    2008-01-01

    In this paper, we present the applications of spatial technologies—Geographic Information Systems (GIS) and remote sensing—in the international monitoring of river basins particularly analyzing the ecological, hydrological, and socio-economic issues along the Senegal River. The literature on multinational water crisis has for decades focused on mediation aspects of trans-boundary watershed management resulting in limited emphasis placed on the application of advances in geo-spatial information technologies in multinational watershed conservation in the arid areas of the West African sub-region within the Senegal River Basin for decision-making and monitoring. While the basin offers life support in a complex ecosystem that stretches across different nations in a mostly desert region characterized by water scarcity and subsistence economies, there exists recurrent environmental stress induced by both socio-economic and physical factors. Part of the problems consists of flooding, drought and limited access to sufficient quantities of water. These remain particularly sensitive issues that are crucial for the health of a rapidly growing population and the economy. The problems are further compounded due to the threats of climate change and the resultant degradation of almost the region’s entire natural resources base. While the pace at which the institutional framework for managing the waters offers opportunities for hydro electricity and irrigated agriculture through the proliferation of dams, it has raised other serious concerns in the region. Even where data exists for confronting these issues, some of them are incompatible and dispersed among different agencies. This not only widens the geo-spatial data gaps, but it hinders the ability to monitor water problems along the basin. This study will fill that gap in research through mix scale methods built on descriptive statistics, GIS and remote sensing techniques by generating spatially referenced data to

  18. Influence of integrated services on postpartum family planning use: a cross-sectional survey from urban Senegal

    PubMed Central

    2013-01-01

    Background Although the majority of postpartum women indicate a desire to delay a next birth, family planning (FP) methods are often not offered to, or taken up by, women in the first year postpartum. This study uses data from urban Senegal to examine exposure to FP information and services at the time of delivery and at child immunization appointments and to determine if these points of integration are associated with greater use of postpartum FP. Methods A representative, household sample of women, ages 15–49, was surveyed from six cities in Senegal in 2011. This study focuses on women who were within two years postpartum (n = 1879). We also include women who were surveyed through exit interviews after a visit to a high volume health facility in the same six cities; clients included were visiting the health facility for delivery, post-abortion care, postnatal care, and child immunization services (n = 794). Descriptive analyses are presented to examine exposure to FP services among postpartum women and women visiting the health facility. Logistic regression models are used to estimate the effect of integrated services on postpartum FP use in the household sample of women. Analyses were conducted using Stata version 12. Results Among exit interview clients, knowledge of integrated services is high but only a few reported receiving FP services. A majority of the women who did not receive FP services indicated an interest in receiving such information and services. Among the household sample of women up to two-years postpartum, those who received FP information at the time of delivery are more likely to be using modern FP postpartum than their counterparts who also delivered in a facility but did not receive such information. Exposure to FP services at an immunization visit was not significantly related to postpartum FP use. Another key finding is that women with greater self-efficacy are more likely to use a modern FP method. Conclusion This study

  19. Selection of antimalarial drug resistance after intermittent preventive treatment of infants and children (IPTi/c) in Senegal.

    PubMed

    Ndiaye, Magatte; Tine, Roger; Faye, Babacar; Ndiaye, Jean L; Diouf, Ibrahima; Lo, Aminata C; Sylla, Khadime; Dieng, Yemou; Hallett, Rachel; Alifrangis, Michael; Gaye, Oumar

    2013-01-01

    Senegal has since 2003 used sulphadoxine-pyrimethamine (SP) for Intermittent Preventive Treatment (IPT) of malaria in risk groups. However, the large-scale IPT strategy may result in increasing drug resistance. Our study investigated the possible impact of SP-IPT given to infants and children on the prevalence of SP-resistant haplotypes in the Plasmodium falciparum genes Pfdhfr and Pfdhps, comparing sites with and without IPTi/c. P. falciparum positives samples (n=352) were collected from children under 5years of age during two cross-sectional surveys in 2010 and 2011 in three health districts (two on IPTi/c and one without IPTi/c intervention) located in the southern part of Senegal. The prevalence of SP-resistance-related haplotypes in Pfdhfr and Pfdhps was determined by nested PCR followed by sequence-specific oligonucleotide probe (SSOP)-ELISA. The prevalence of the Pfdhfr double mutant haplotypes (CNRN and CICN) was stable between years at<10% in the control group (P=0.69), while it rose significantly in the IPTi/c group from 2% in 2010 to 20% in 2011 (P=0.008). The prevalence of the Pfdhfr triple mutant haplotype (CIRN) increased in both groups, but only significantly in the IPTi/c group from 41% to 65% in 2011 (P=0.005). Conversely, the Pfdhps 437G mutation decreased in both groups from 44.6% to 28.6% (P=0.07) and from 66.7% to 47.5% (P=0.02) between 2010 and 2011 in the control and the IPTi/c groups, respectively. Combined with Pfdhfr, there was a weak trend for decreasing prevalence of quadruple mutants (triple Pfdhfr+Pfdhps 437G) in both groups (P=0.15 and P=0.34). During the two cross-sectional surveys, some significant changes were observed in the SP-resistance-related genes. However, since these changes were observed in the two groups, the IPTi/c strategy does only seem to have limited impact on resistance development and other factors as well. However, continuous monitoring will be needed, due to the up-scaling of the IPTi/c strategy in Senegal

  20. Using spatial information technologies as monitoring devices in international watershed conservation along the Senegal River Basin of West Africa.

    PubMed

    Merem, Edmund C; Twumasi, Yaw A

    2008-12-01

    In this paper, we present the applications of spatial technologies-Geographic Information Systems (GIS) and remote sensing-in the international monitoring of river basins particularly analyzing the ecological, hydrological, and socio-economic issues along the Senegal River. The literature on multinational water crisis has for decades focused on mediation aspects of trans-boundary watershed management resulting in limited emphasis placed on the application of advances in geo-spatial information technologies in multinational watershed conservation in the arid areas of the West African sub-region within the Senegal River Basin for decision-making and monitoring. While the basin offers life support in a complex ecosystem that stretches across different nations in a mostly desert region characterized by water scarcity and subsistence economies, there exists recurrent environmental stress induced by both socio-economic and physical factors. Part of the problems consists of flooding, drought and limited access to sufficient quantities of water. These remain particularly sensitive issues that are crucial for the health of a rapidly growing population and the economy. The problems are further compounded due to the threats of climate change and the resultant degradation of almost the region's entire natural resources base. While the pace at which the institutional framework for managing the waters offers opportunities for hydro electricity and irrigated agriculture through the proliferation of dams, it has raised other serious concerns in the region. Even where data exists for confronting these issues, some of them are incompatible and dispersed among different agencies. This not only widens the geo-spatial data gaps, but it hinders the ability to monitor water problems along the basin. This study will fill that gap in research through mix scale methods built on descriptive statistics, GIS and remote sensing techniques by generating spatially referenced data to supplement

  1. Effects of the sandbar breaching on hydrobiological parameters and zooplankton communities in the Senegal River Estuary (West Africa).

    PubMed

    Champalbert, Gisèle; Pagano, Marc; Arfi, Robert; Chevalier, Cristèle

    2014-05-15

    This study describes the changes in hydrology, zooplankton communities and abundance in the Senegal River Estuary (SRE) before and after the breaching of the sandbar in October 2003. Samples were taken in 2003 at 3 stations located upstream (DI), in mid estuary (HY) and downstream (RM), and in 2005 at the same stations (RM becoming Old River Mouth: ORM), plus the new river mouth (NRM) resulting from the morphological evolution of the SRE. The study showed marked seasonal variations that affected the structure and distribution of zooplankton as well as major changes caused by the sandbar opening: increased marine influence throughout the whole SRE, changes in the horizontal gradients, arrival of euryhaline species and increase in meroplankton, in particular decapod larvae, transformation of the ORM area into a slackwater area with limited exchanges and the highest zooplankton numbers during high waters. PMID:24685450

  2. Emergence of Mutations in the K13 Propeller Gene of Plasmodium falciparum Isolates from Dakar, Senegal, in 2013-2014.

    PubMed

    Boussaroque, Agathe; Fall, Bécaye; Madamet, Marylin; Camara, Cheikhou; Benoit, Nicolas; Fall, Mansour; Nakoulima, Aminata; Dionne, Pierre; Fall, Kadidiatou Ba; Diatta, Bakary; Diémé, Yaya; Wade, Boubacar; Pradines, Bruno

    2016-01-01

    The kelch 13 (K13) propeller gene is associated with artemisinin resistance. In a previous work, there were no mutations found in 138 Plasmodium falciparum isolates collected in 2012 and 2013 from patients residing in Dakar, Senegal (M. Torrentino-Madamet et al., Malar J 13:472, 2014, http://dx.doi.org/10.1186/1475-2875-13-472). However, the N554H, Q613H, and V637I mutations were identified in the propeller region of K13 in 92 (5.5%) isolates in 2013 and 2014. There were five polymorphisms identified in the Plasmodium/Apicomplexa-specific domain (K123R, N137S, N142NN/NNN, T149S, and K189T/N). PMID:26503652

  3. Emergence of Mutations in the K13 Propeller Gene of Plasmodium falciparum Isolates from Dakar, Senegal, in 2013-2014

    PubMed Central

    Boussaroque, Agathe; Fall, Bécaye; Madamet, Marylin; Camara, Cheikhou; Benoit, Nicolas; Fall, Mansour; Nakoulima, Aminata; Dionne, Pierre; Fall, Kadidiatou Ba; Diatta, Bakary; Diémé, Yaya; Wade, Boubacar

    2015-01-01

    The kelch 13 (K13) propeller gene is associated with artemisinin resistance. In a previous work, there were no mutations found in 138 Plasmodium falciparum isolates collected in 2012 and 2013 from patients residing in Dakar, Senegal (M. Torrentino-Madamet et al., Malar J 13:472, 2014, http://dx.doi.org/10.1186/1475-2875-13-472). However, the N554H, Q613H, and V637I mutations were identified in the propeller region of K13 in 92 (5.5%) isolates in 2013 and 2014. There were five polymorphisms identified in the Plasmodium/Apicomplexa-specific domain (K123R, N137S, N142NN/NNN, T149S, and K189T/N). PMID:26503652

  4. Acceptability and Feasibility of Delivering Pentavalent Vaccines in a Compact, Prefilled, Autodisable Device in Vietnam and Senegal

    PubMed Central

    Guillermet, Elise; Dicko, Hamadou M.; Mai, Le Thi Phuong; N’Diaye, Mamadou; Hane, Fatoumata; Ba, Seydina Ousmane; Gomis, Khadidjatou; Tho, Nguyen Thi Thi; Lien, Nguyen Thi Phuong; Than, Phan Dang; Dinh, Tran Van; Jaillard, Philippe; Gessner, Bradford D.; Colombini, Anais

    2015-01-01

    Background Prefilled syringes are the standard in developed countries but logistic and financial barriers prevent their widespread use in developing countries. The current study evaluated use of a compact, prefilled, autodisable device (CPAD) to deliver pentavalent vaccine by field actors in Senegal and Vietnam. Methods We conducted a logistic, programmatic, and anthropological study that included a) interviews of immunization staff at different health system levels and parents attending immunization sessions; b) observation of immunization sessions including CPAD use on oranges; and c) document review. Results Respondents perceived that the CPAD would improve safety by being non-reusable and preventing needle and vaccine exposure during preparation. Preparation was considered simple and may reduce immunization time for staff and caretakers. CPAD impact on cold storage requirements depended on the current pentavalent vaccine being used; in both countries, CPAD would reduce the weight and volume of materials and safety boxes thereby potentially improving outreach strategies and waste disposal. CPAD also would reduce stock outages by bundling vaccine and syringes and reduce wastage by using a non-breakable plastic presentation. Respondents also cited potential challenges including ability to distinguish between CPAD and other pharmaceuticals delivered via a similar mechanism (such as contraceptives), safety, and concerns related to design and ease of administration (such as activation, ease of delivery, and needle diameter and length). Conclusions Compared to current pentavalent vaccine presentations in Vietnam and Senegal, CPAD technology will address some of the main barriers to vaccination, such as supply chain issues and safety concerns among health workers and families. Most of the challenges we identified can be addressed with health worker training, minor design modifications, and health messaging targeting parents and communities. Potentially the largest

  5. Building hazard maps of extreme daily rainy events from PDF ensemble, via REA method, on Senegal River Basin

    NASA Astrophysics Data System (ADS)

    Giraldo Osorio, J. D.; García Galiano, S. G.

    2011-11-01

    The Sudano-Sahelian zone of West Africa, one of the poorest of the Earth, is characterized by high rainfall variability and rapid population growth. In this region, heavy storm events frequently cause extensive damage. Nonetheless, the projections for change in extreme rainfall values have shown a great divergence between Regional Climate Models (RCM), increasing the forecast uncertainty. Novel methodologies should be applied, taking into account both the variability provided by different RCMs, as well as the non-stationary nature of time series for the building of hazard maps of extreme rainfall events. The present work focuses on the probability density functions (PDFs)-based evaluation and a simple quantitative measure of how well each RCM considered can capture the observed annual maximum daily rainfall (AMDR) series on the Senegal River basin. Since meaningful trends have been detected in historical rainfall time series for the region, non-stationary probabilistic models were used to fit the PDF parameters to the AMDR time series. In the development of PDF ensemble by bootstrapping techniques, Reliability Ensemble Averaging (REA) maps were applied to score the RCMs. The REA factors were computed using a metric to evaluate the agreement between observed -or best estimated- PDFs, and that simulated with each RCM. The assessment of plausible regional trends associated to the return period, from the hazard maps of AMDR, showed a general rise, owing to an increase in the mean and the variability of extreme precipitation. These spatial-temporal distributions could be considered by Organization for the Development of the Senegal River (Organisation pour la mise en valeur du fleuve Sénégal, OMVS), in such a way as to reach a better balance between mitigation and adaptation.

  6. "Right tool," wrong "job": Manual vacuum aspiration, post-abortion care and transnational population politics in Senegal.

    PubMed

    Suh, Siri

    2015-06-01

    The "rightness" of a technology for completing a particular task is negotiated by medical professionals, patients, state institutions, manufacturing companies, and non-governmental organizations. This paper shows how certain technologies may challenge the meaning of the "job" they are designed to accomplish. Manual vacuum aspiration (MVA) is a syringe device for uterine evacuation that can be used to treat complications of incomplete abortion, known as post-abortion care (PAC), or to terminate pregnancy. I explore how negotiations over the rightness of MVA as well as PAC unfold at the intersection of national and global reproductive politics during the daily treatment of abortion complications at three hospitals in Senegal, where PAC is permitted but induced abortion is legally prohibited. Although state health authorities have championed MVA as the "preferred" PAC technology, the primary donor for PAC, the United States Agency for International Development, does not support the purchase of abortifacient technologies. I conducted an ethnography of Senegal's PAC program between 2010 and 2011. Data collection methods included interviews with 49 health professionals, observation of PAC treatment and review of abortion records at three hospitals, and a review of transnational literature on MVA and PAC. While MVA was the most frequently employed form of uterine evacuation in hospitals, concerns about off-label MVA practices contributed to the persistence of less effective methods such as dilation and curettage (D&C) and digital curettage. Anxieties about MVA's capacity to induce abortion have constrained its integration into routine obstetric care. This capacity also raises questions about what the "job," PAC, represents in Senegalese hospitals. The prioritization of MVA's security over women's access to the preferred technology reinforces gendered inequalities in health care. PMID:25948127

  7. Changes in Habitat Structure May Explain Decrease in Reintroduced Mohor Gazelle Population in the Guembeul Fauna Reserve, Senegal

    PubMed Central

    Moreno, Eulalia; Sane, Abibou; Benzal, Jesús; Ibáñez, Belén; Sanz-Zuasti, Joaquín; Espeso, Gerardo

    2012-01-01

    Simple Summary The reintroduction of plants and animals to the wild is an important technique to save endangered species from extinction. To perform post release monitoring is crucial to evaluate reintroduction outcomes. A Mohor gazelle reintroduction programme took place in Senegal in 1984. We attempt to explain why the size of the reintroduced gazelle population has diminished in recent years. We suggest that changes in habitat structure occurred over time and have very likely reduced the amount of suitable habitat for this species. Abstract Reintroduction is a widespread method for saving populations of endangered species from extinction. In spite of recent reviews, it is difficult to reach general conclusions about its value as a conservation tool, as authors are reluctant to publish unsuccessful results. The Mohor gazelle is a North African gazelle, extinct in the wild. Eight individuals were reintroduced in Senegal in 1984. The population grew progressively, albeit slowly, during the first 20 years after release, but then declined dramatically, until the population in 2009 was estimated at no more than 13–15 individuals. This study attempts to determine the likelihood of gazelle-habitat relationships to explain why the size of the gazelle population has diminished. Our results show that the Mohor gazelle in Guembeul is found in open habitats with less developed canopy where the grass is shorter, suggesting the possibility that changes in habitat structure have taken place during the time the gazelles have been in the Reserve, reducing the amount of suitable habitat. Reintroduction design usually concentrates on short-term factors that may affect survival of the released animals and their descendants (short-term achievement), while the key factors for assessing its success may be those that affect the long-term evolution of the population. PMID:26487026

  8. Prevalence of molecular markers of Plasmodium falciparum drug resistance in Dakar, Senegal

    PubMed Central

    2012-01-01

    Background As a result of the widespread resistance to chloroquine and sulphadoxine-pyrimethamine, artemisinin-based combination therapy (ACT) (including artemether-lumefantrine and artesunate-amodiaquine) has been recommended as a first-line anti-malarial regimen in Senegal since 2006. Intermittent preventive treatments with anti-malarial drugs based on sulphadoxine-pyrimethamine are also given to children or pregnant women once per month during the transmission season. Since 2006, there have been very few reports on the susceptibility of Plasmodium falciparum to anti-malarial drugs. To estimate the prevalence of resistance to several anti-malarial drugs since the introduction of the widespread use of ACT, the presence of molecular markers associated with resistance to chloroquine and sulphadoxine-pyrimethamine was assessed in local isolates at the military hospital of Dakar. Methods The prevalence of genetic polymorphisms in genes associated with anti-malarial drug resistance, i.e., Pfcrt, Pfdhfr, Pfdhps and Pfmdr1, and the copy number of Pfmdr1 were evaluated for a panel of 174 isolates collected from patients recruited at the military hospital of Dakar from 14 October 2009 to 19 January 2010. Results The Pfcrt 76T mutation was identified in 37.2% of the samples. The Pfmdr1 86Y and 184F mutations were found in 16.6% and 67.6% of the tested samples, respectively. Twenty-eight of the 29 isolates with the 86Y mutation were also mutated at codon 184. Only one isolate (0.6%) had two copies of Pfmdr1. The Pfdhfr 108N/T, 51I and 59R mutations were identified in 82.4%, 83.5% and 74.1% of the samples, respectively. The double mutant (108N and 51I) was detected in 83.5% of the isolates, and the triple mutant (108N, 51I and 59R) was detected in 75.3%. The Pfdhps 437G, 436F/A and 613S mutations were found in 40.2%, 35.1% and 1.8% of the samples, respectively. There was no double mutant (437G and 540E) or no quintuple mutant (Pfdhfr 108N, 51I and 59R and Pfdhps 437G and 540E

  9. Decline of Pseudodiaptomus hessei (Copepoda, Calanoida) in two water bodies located in the Senegal River hydrosystem (West Africa): Hypotheses and perspectives

    NASA Astrophysics Data System (ADS)

    Mendoza-Vera, Juana Mireya; Kâ, Samba; Cuoc, Corinne; Bouvy, Marc; Pagano, Marc

    2008-09-01

    Pseudodiaptomus hessei is a key species in many water bodies in the Senegal River hydrosystem but it became rare or completely disappeared from two ecosystems (Lake Guiers and Dakar Bango Reservoir; Senegal, West Africa) after major hydrological changes caused by human action, mainly impoundments on the river in 1985, and the opening of a new estuary mouth in 2003. Kâ et al. [Kâ, S., Pagano, M., Ba, N., Bouvy, M., Leboulanger, C., Arfi, R., Thiaw, O.T., Ndour, E.H.M., Corbin, D., Defaye, D., Cuoc, C., Kouassi, E., 2006. Zooplankton distribution related to environmental factors and phytoplankton in a shallow tropical lake (Lake Guiers, Senegal, West Africa). International Review of Hydrobiology 91(5), 389-405] put forward several hypotheses to explain the reasons for this decline: salinity and chemical changes in the water, predation by a cyclopid predator Mesocyclops ogunnus and/or the inhibiting effects of cyanobacteria and/or diatoms (allelopathy). This study assessed these hypotheses by studying the distribution of P. hessei in 13 stations (including the Dakar Bango reservoir and Lake Guiers) in relation to physical, chemical and biological (phyto- and zooplanktons) factors at each station. We produced a distribution pattern for this species in the Senegal River hydrosystem. Rank correlations and principal component analysis showed that P. hessei was not correlated with conductivity but was positively correlated with pH and alkalinity, suggesting chemical effects. The clear association with two filamentous cyanobacteria ( Cylindrospermopsis raciborskii and Anabaena sp.) did not appear to support the hypothesis of cyanobacteria inhibition but blooming conditions were never encountered during the study. Negative correlation with diatoms (especially with Fragilaria sp.) suggested that aldehyde producing diatoms had a negative effect. Negative correlations with cyclopids such as Mesocyclops supported the hypothesis of cyclopid predation to explain the decline of P

  10. Seasonal dynamics of Culicoides (Diptera: Ceratopogonidae) biting midges, potential vectors of African horse sickness and bluetongue viruses in the Niayes area of Senegal

    PubMed Central

    2014-01-01

    Background The African horse sickness epizootic in Senegal in 2007 caused considerable mortality in the equine population and hence major economic losses. The vectors involved in the transmission of this arbovirus have never been studied specifically in Senegal. This first study of the spatial and temporal dynamics of the Culicoides (Diptera: Ceratopogonidae) species, potential vectors of African horse sickness in Senegal, was conducted at five sites (Mbao, Parc Hann, Niague, Pout and Thies) in the Niayes area, which was affected by the outbreak. Methods Two Onderstepoort light traps were used at each site for three nights of consecutive collection per month over one year to measure the apparent abundance of the Culicoides midges. Results In total, 224,665 specimens belonging to at least 24 different species (distributed among 11 groups of species) of the Culicoides genus were captured in 354 individual collections. Culicoides oxystoma, Culicoides kingi, Culicoides imicola, Culicoides enderleini and Culicoides nivosus were the most abundant and most frequent species at the collection sites. Peaks of abundance coincide with the rainy season in September and October. Conclusions In addition to C. imicola, considered a major vector for the African horse sickness virus, C. oxystoma may also be involved in the transmission of this virus in Senegal given its abundance in the vicinity of horses and its suspected competence for other arboviruses including bluetongue virus. This study depicted a site-dependent spatial variability in the dynamics of the populations of the five major species in relation to the eco-climatic conditions at each site. PMID:24690198

  11. Universality in fragment inclusive yields from Au+Au collisions

    NASA Astrophysics Data System (ADS)

    Insolia, A.; Tuvè, C.; Albergo, S.; Bieser, F.; Brady, F. P.; Caccia, Z.; Cebra, D.; Chacon, A. D.; Chance, J. L.; Choi, Y.; Costa, S.; Elliott, J. B.; Gilkes, M.; Hauger, J. A.; Hirsch, A. S.; Hjort, E. L.; Justice, M.; Keane, D.; Kintner, J.; Lisa, M.; Matis, H. S.; McMahan, M.; McParland, C.; Olson, D. L.; Partlan, M. D.; Porile, N. T.; Potenza, R.; Rai, G.; Rasmussen, J.; Ritter, H. G.; Romero, J. L.; Russo, G. V.; Scharenberg, R.; Scott, A.; Shao, Y.; Srivastava, B. K.; Symons, T. J. M.; Tincknell, M. L.; Wang, S.; Warren, P. G.; Wieman, H. H.; Wolf, K. L.

    2001-11-01

    The inclusive light fragment (Z⩽7) yield data in Au+Au reactions, measured by the EOS Collaboration at the LBNL Bevalac, are presented and discussed. For peripheral collisions the measured charge distributions develop progressively according to a power law which can be fitted by a single τ exponent independently of the bombarding energy in the range 250-1200 A MeV. In addition to this universal feature, we observe that the location of the maximum in the individual yields of different charged fragments shift towards lower multiplicity as the fragment charge increases from Z=3 to Z=7. This trend is common to all six measured beam energies. Moments of charge distributions and correlations among different moments are reported. Finally, the THe,DT thermometer has been constructed for central and peripheral collisions using the double yield ratios of He and D, T projectile fragments. The measured nuclear temperatures are in agreement with experimental findings in other fragmentation reactions.

  12. Global polarization measurement in Au+Au collisions

    SciTech Connect

    Abelev, B.I.; Adams, J.; Aggarwal, M.M.; Ahammed, Z.; Amonett,J.; Anderson, B.D.; Anderson, M.; Arkhipkin, D.; Averichev, G.S.; Bai,Y.; Balewski, J.; Barannikova, O.; Barnby, L.S.; Baudot, J.; Bekele, S.; Belaga, V.V.; Bellingeri-Laurikainen, A.; Bellwied, R.; Benedosso, F.; Bhardwaj, S.; Bhasin, A.; Bhati, A.K.; Bichsel, H.; Bielcik, J.; Bielcikova, J.; Bland, L.C.; Blyth, S.-L.; Bonner, B.E.; Botje, M.; Bouchet, J.; Brandin, A.V.; Bravar, A.; Bystersky, M.; Cadman, R.V.; Cai,X.Z.; Caines, H.; Calderon de la Barca Sanchez, M.; Castillo, J.; Catu,O.; Cebra, D.; Chajecki, Z.; Chaloupka, P.; Chattopadhyay, S.; Chen,H.F.; Chen, J.H.; Cheng, J.; Cherney, M.; Chikanian, A.; Christie, W.; Coffin, J.P.; Cormier, T.M.; Cosentino, M.R.; Cramer, J.G.; Crawford,H.J.; Das, D.; Das, S.; Daugherity, M.; de Moura, M.M.; Dedovich, T.G.; DePhillips, M.; Derevschikov, A.A.; Didenko, L.; Dietel, T.; Djawotho,P.; Dogra, S.M.; Dong, W.J.; Dong, X.; Draper, J.E.; Du, F.; Dunin, V.B.; Dunlop, J.C.; Dutta Mazumdar, M.R.; Eckardt, V.; Edwards, W.R.; Efimov,L.G.; Emelianov, V.; Engelage, J.; Eppley, G.; Erazmus, B.; Estienne, M.; Fachini, P.; Fatemi, R.; Fedorisin, J.; Filimonov, K.; Filip, P.; Finch,E.; Fine, V.; Fisyak, Y.; Fu, J.; Gagliardi, C.A.; Gaillard, L.; Ganti,M.S.; Ghazikhanian, V.; Ghosh, P.; Gonzalez, J.S.; Gorbunov, Y.G.; Gos,H.; Grebenyuk, O.; Grosnick, D.; Guertin, S.M.; Guimaraes, K.S.F.F.; Guo,Y.; Gupta, N.; Gutierrez, T.D.; Haag, B.; Hallman, T.J.; Hamed, A.; Harris, J.W.; He, W.; Heinz, M.; Henry, T.W.; Hepplemann, S.; Hippolyte,B.; Hirsch, A.; Hjort, E.; Hoffman, A.M.; Hoffmann, G.W.; Horner, M.J.; Huang, H.Z.; Huang, S.L.; Hughes, E.W.; Humanic, T.J.; Igo, G.; Jacobs,P.; Jacobs, W.W.; Jakl, P.; Jia, F.; Jiang, H.; Jones, P.G.; Judd, E.G.; Kabana, S.; Kang, K.; Kapitan, J.; Kaplan, M.; Keane, D.; Kechechyan, A.; Khodyrev,V.Yu.; Kim, B.C.; Kiryluk, J.; Kisiel, A.; Kislov, E.M.; Klein,S.R.; Kocoloski, A.; Koetke, D.D.; et al.

    2007-08-02

    The system created in non-central relativisticnucleus-nucleus collisions possesses large orbital angular momentum. Dueto spin-orbit coupling, particles produced in such a system could becomeglobally polarized along the direction of the system angular momentum. Wepresent the results of Lambda and anti-Lambda hyperon global polarizationmeasurements in Au+Au collisions at sqrt sNN=62.4 GeV and 200 GeVperformed with the STAR detector at RHIC. The observed globalpolarization of Lambda and anti-Lambda hyperons in the STAR acceptance isconsistent with zero within the precision of the measurements. Theobtained upper limit, lbar P Lambda, anti-Lambda rbar<= 0.02, iscompared to the theoretical values discussed recently in theliterature.

  13. Nuclear Modification of Jet Fragmentation in Au+Au Collisions

    NASA Astrophysics Data System (ADS)

    Rowan, Zachary; Phenix Collaboration

    2015-10-01

    The characterization of energy in the quark gluon plasma is facilitated by measurements of modifications to the observed jet fragmentation. A favorable channel of study relies on direct photons created in the initial parton interactions of heavy ion collisions. Such a photon traverses the created medium unscathed and grants us a proxy for the transverse momentum of an away side jet. PHENIX Au+Au data recorded at √{sNN} = 200 GeV during RHIC run 14 benefit from the background rejection capability of the silicon vertex detector, enabling the extraction of a higher purity hadron signal. This advantage, combined with a larger integrated luminosity, allows previous PHENIX measurements of fragmentation functions to be extended to greater jet energies. In this talk, the status of the analysis of direct photon hadron correlations with the new data set will be discussed.

  14. Global polarization measurement in Au+Au collisions

    NASA Astrophysics Data System (ADS)

    Abelev, B. I.; Aggarwal, M. M.; Ahammed, Z.; Anderson, B. D.; Arkhipkin, D.; Averichev, G. S.; Bai, Y.; Balewski, J.; Barannikova, O.; Barnby, L. S.; Baudot, J.; Baumgart, S.; Belaga, V. V.; Bellingeri-Laurikainen, A.; Bellwied, R.; Benedosso, F.; Betts, R. R.; Bhardwaj, S.; Bhasin, A.; Bhati, A. K.; Bichsel, H.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Blyth, S.-L.; Bombara, M.; Bonner, B. E.; Botje, M.; Bouchet, J.; Brandin, A. V.; Burton, T. P.; Bystersky, M.; Cai, X. Z.; Caines, H.; Sánchez, M. Calderón De La Barca; Callner, J.; Catu, O.; Cebra, D.; Cervantes, M. C.; Chajecki, Z.; Chaloupka, P.; Chattopadhyay, S.; Chen, H. F.; Chen, J. H.; Chen, J. Y.; Cheng, J.; Cherney, M.; Chikanian, A.; Christie, W.; Chung, S. U.; Clarke, R. F.; Codrington, M. J. M.; Coffin, J. P.; Cormier, T. M.; Cosentino, M. R.; Cramer, J. G.; Crawford, H. J.; Das, D.; Dash, S.; Daugherity, M.; Moura, M. M. De; Dedovich, T. G.; Dephillips, M.; Derevschikov, A. A.; Didenko, L.; Dietel, T.; Djawotho, P.; Dogra, S. M.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Du, F.; Dunin, V. B.; Dunlop, J. C.; Mazumdar, M. R. Dutta; Edwards, W. R.; Efimov, L. G.; Emelianov, V.; Engelage, J.; Eppley, G.; Erazmus, B.; Estienne, M.; Fachini, P.; Fatemi, R.; Fedorisin, J.; Feng, A.; Filip, P.; Finch, E.; Fine, V.; Fisyak, Y.; Fu, J.; Gagliardi, C. A.; Gaillard, L.; Ganti, M. S.; Garcia-Solis, E.; Ghazikhanian, V.; Ghosh, P.; Gorbunov, Y. N.; Gos, H.; Grebenyuk, O.; Grosnick, D.; Grube, B.; Guertin, S. M.; Guimaraes, K. S. F. F.; Gupta, A.; Gupta, N.; Haag, B.; Hallman, T. J.; Hamed, A.; Harris, J. W.; He, W.; Heinz, M.; Henry, T. W.; Heppelmann, S.; Hippolyte, B.; Hirsch, A.; Hjort, E.; Hoffman, A. M.; Hoffmann, G. W.; Hofman, D. J.; Hollis, R. S.; Horner, M. J.; Huang, H. Z.; Hughes, E. W.; Humanic, T. J.; Igo, G.; Iordanova, A.; Jacobs, P.; Jacobs, W. W.; Jakl, P.; Jones, P. G.; Judd, E. G.; Kabana, S.; Kang, K.; Kapitan, J.; Kaplan, M.; Keane, D.; Kechechyan, A.; Kettler, D.; Khodyrev, V. Yu.; Kiryluk, J.; Kisiel, A.; Kislov, E. M.; Klein, S. R.; Knospe, A. G.; Kocoloski, A.; Koetke, D. D.; Kollegger, T.; Kopytine, M.; Kotchenda, L.; Kouchpil, V.; Kowalik, K. L.; Kravtsov, P.; Kravtsov, V. I.; Krueger, K.; Kuhn, C.; Kulikov, A. I.; Kumar, A.; Kurnadi, P.; Kuznetsov, A. A.; Lamont, M. A. C.; Landgraf, J. M.; Lange, S.; Lapointe, S.; Laue, F.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, C.-H.; Lehocka, S.; Levine, M. J.; Li, C.; Li, Q.; Li, Y.; Lin, G.; Lin, X.; Lindenbaum, S. J.; Lisa, M. A.; Liu, F.; Liu, H.; Liu, J.; Liu, L.; Ljubicic, T.; Llope, W. J.; Longacre, R. S.; Love, W. A.; Lu, Y.; Ludlam, T.; Lynn, D.; Ma, G. L.; Ma, J. G.; Ma, Y. G.; Mahapatra, D. P.; Majka, R.; Mangotra, L. K.; Manweiler, R.; Margetis, S.; Markert, C.; Martin, L.; Matis, H. S.; Matulenko, Yu. A.; McShane, T. S.; Meschanin, A.; Millane, J.; Miller, M. L.; Minaev, N. G.; Mioduszewski, S.; Mischke, A.; Mitchell, J.; Mohanty, B.; Morozov, D. A.; Munhoz, M. G.; Nandi, B. K.; Nattrass, C.; Nayak, T. K.; Nelson, J. M.; Nepali, C.; Netrakanti, P. K.; Nogach, L. V.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Okorokov, V.; Olson, D.; Pachr, M.; Pal, S. K.; Panebratsev, Y.; Pavlinov, A. I.; Pawlak, T.; Peitzmann, T.; Perevoztchikov, V.; Perkins, C.; Peryt, W.; Phatak, S. C.; Planinic, M.; Pluta, J.; Poljak, N.; Porile, N.; Poskanzer, A. M.; Potekhin, M.; Potrebenikova, E.; Potukuchi, B. V. K. S.; Prindle, D.; Pruneau, C.; Pruthi, N. K.; Putschke, J.; Qattan, I. A.; Raniwala, R.; Raniwala, S.; Ray, R. L.; Relyea, D.; Ridiger, A.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Rose, A.; Roy, C.; Ruan, L.; Russcher, M. J.; Sahoo, R.; Sakrejda, I.; Sakuma, T.; Salur, S.; Sandweiss, J.; Sarsour, M.; Sazhin, P. S.; Schambach, J.; Scharenberg, R. P.; Schmitz, N.; Seger, J.; Selyuzhenkov, I.; Seyboth, P.; Shabetai, A.; Shahaliev, E.; Shao, M.; Sharma, M.; Shen, W. Q.; Shimanskiy, S. S.; Sichtermann, E. P.; Simon, F.; Singaraju, R. N.; Smirnov, N.; Snellings, R.; Sorensen, P.; Sowinski, J.; Speltz, J.; Spinka, H. M.; Srivastava, B.; Stadnik, A.; Stanislaus, T. D. S.; Staszak, D.; Stock, R.; Strikhanov, M.; Stringfellow, B.; Suaide, A. A. P.; Suarez, M. C.; Subba, N. L.; Sumbera, M.; Sun, X. M.; Sun, Z.; Surrow, B.; Symons, T. J. M.; Toledo, A. Szanto De; Takahashi, J.; Tang, A. H.; Tarnowsky, T.; Thomas, J. H.; Timmins, A. R.; Timoshenko, S.; Tokarev, M.; Trainor, T. A.; Trentalange, S.; Tribble, R. E.; Tsai, O. D.; Ulery, J.; Ullrich, T.; Underwood, D. G.; Buren, G. Van; Kolk, N. Van Der; Leeuwen, M. Van; Molen, A. M. Vander; Varma, R.; Vasilevski, I. M.; Vasiliev, A. N.; Vernet, R.; Vigdor, S. E.; Viyogi, Y. P.; Vokal, S.; Voloshin, S. A.; Wada, M.; Waggoner, W. T.; Wang, F.; Wang, G.; Wang, J. S.; Wang, X. L.; Wang, Y.; Webb, J. C.; Westfall, G. D.; , C. Whitten, Jr.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, J.; Wu, Y.; Xu, N.; Xu, Q. H.; Xu, Z.; Yepes, P.; Yoo, I.-K.; Yue, Q.; Yurevich, V. I.; Zawisza, M.; Zhan, W.; Zhang, H.; Zhang, W. M.; Zhang, Y.; Zhang, Z. P.; Zhao, Y.; Zhong, C.; Zhou, J.; Zoulkarneev, R.; Zoulkarneeva, Y.; Zubarev, A. N.; Zuo, J. X.

    2007-08-01

    The system created in noncentral relativistic nucleus-nucleus collisions possesses large orbital angular momentum. Because of spin-orbit coupling, particles produced in such a system could become globally polarized along the direction of the system angular momentum. We present the results of Λ and Λ¯ hyperon global polarization measurements in Au+Au collisions at sNN=62.4 and 200 GeV performed with the STAR detector at the BNL Relativistic Heavy Ion Collider (RHIC). The observed global polarization of Λ and Λ¯ hyperons in the STAR acceptance is consistent with zero within the precision of the measurements. The obtained upper limit, |PΛ,Λ¯|⩽0.02, is compared with the theoretical values discussed recently in the literature.

  15. d + Au hadron correlation measurements at PHENIX

    SciTech Connect

    Anne M. Sickles

    2014-05-13

    In these proceedings, we discuss recent results from d + Au collisions in PHENIX ridge related measurements and their possible hydrodynamic origin. We present the v2 at midrapidity and measurements of the pseudorapidity dependence of the ridge, distinguishing between the d-going and Au-going directions. We investigate the possible geometrical origin by comparing v2 in d + Au to that in p + Pb, Au + Au and Pb + Pb collisions. Future plans to clarify the role of geometry in small collision systems at RHIC are discussed.

  16. Cometary Activity Beyond 4 AU

    NASA Astrophysics Data System (ADS)

    Womack, M.

    2000-10-01

    Recent observations of the distantly active comets 29 P/Schwassmann-Wachmann 1, 2060 Chiron, and C/1995 O1 (Hale-Bopp) are consistent with models that predict that the activity beyond 4 AU is dominated by outgassing of CO and CO2 molecules trapped in an amorphous water ice surface undergoing crystallization. The nominal CO production rates in Hale-Bopp, SW 1 and Chiron over the range of r = 4 to 9 AU are consistent with Q(CO) = (2.9+/-0.5)x1030r{(-2.5 +/- 0.1)}, with sporadic outbursts superimposed. The data indicate that the gas production rates in distant comets are primarily determined by the composition, and not the size, of the nucleus. The dust production rates, however, are very different among these comets and are not well-correlated with heliocentric distance. Thus, the gas and dust mixtures may not be uniform amongst these comets, nor in an individual comet. Development and sublimation of an icy grain coma at ~ 5 AU appears to be a common feature in distantly active comets. Sublimation of such icy grains is probably the main source of emission of OH, CH3OH, HCN, and H2S in comets beyond 4 AU. Studying the energetics of these phenomena provides an excellent opportunity to learn more about the composition and physical behavior of comet nuclei, as well as other icy bodies in the outer solar system, such as moons and Kuiper Belt Objects. This work was funded by the NSF CAREER Program.

  17. Synthesis and optical property characterization of elongated AuPt and Pt@Au metal nanoframes

    NASA Astrophysics Data System (ADS)

    Lee, Sangji; Jang, Hee-Jeong; Jang, Ho Young; Hong, Soonchang; Moh, Sang Hyun; Park, Sungho

    2016-02-01

    We report a facile method to synthesize elongated nanoframes consisting of Pt and Au in solution. Pentagonal Au nanorods served as templates and successfully led to an elongated AuPt nanoframe after etching the core Au. Subsequently, the coating of Au around Pt ridges resulted in Pt@Au metal nanoframes. The resulting elongated nanostructure exhibited 5 well-defined ridges continuously connected along the long axis. During the shape evolution from pure Au nanorods to elongated Pt@Au metal nanoframes, their corresponding localized surface plasmon resonance bands were monitored. Especially, unique surface plasmon features were observed for elongated Pt@Au nanoframes where the short-axis oscillation of surface free electrons is strongly coupled but the long-axis oscillation is not coupled among the ridges.We report a facile method to synthesize elongated nanoframes consisting of Pt and Au in solution. Pentagonal Au nanorods served as templates and successfully led to an elongated AuPt nanoframe after etching the core Au. Subsequently, the coating of Au around Pt ridges resulted in Pt@Au metal nanoframes. The resulting elongated nanostructure exhibited 5 well-defined ridges continuously connected along the long axis. During the shape evolution from pure Au nanorods to elongated Pt@Au metal nanoframes, their corresponding localized surface plasmon resonance bands were monitored. Especially, unique surface plasmon features were observed for elongated Pt@Au nanoframes where the short-axis oscillation of surface free electrons is strongly coupled but the long-axis oscillation is not coupled among the ridges. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr08200e

  18. Ex vivo susceptibility of Plasmodium falciparum isolates from Dakar, Senegal, to seven standard anti-malarial drugs

    PubMed Central

    2011-01-01

    Background As a result of widespread chloroquine and sulphadoxine-pyrimethamine resistance, artemisinin-based combination therapy (ACT) (which includes artemether-lumefantrine and artesunate-amodiaquine) has been recommended as a first-line anti-malarial regimen in Senegal since 2006. Since then, there have been very few reports on the ex vivo susceptibility of Plasmodium falciparum to anti-malarial drugs. To examine whether parasite susceptibility has been affected by the widespread use of ACT, the ex vivo susceptibility of local isolates was assessed at the military hospital of Dakar. Methods The ex vivo susceptibility of 93 P. falciparum isolates from Dakar was successfully determined using the Plasmodium lactate dehydrogenase (pLDH) ELISA for the following drugs: chloroquine (CQ), quinine (QN), mefloquine (MQ), monodesethylamodiaquine (MDAQ), lumefantrine (LMF), dihydroartemisinin (DHA) and doxycycline (DOX). Results After transformation of the isolate IC50 in ratio of IC50 according to the susceptibility of the 3D7 reference strain (isolate IC50/3D7 IC50), the prevalence of the in vitro resistant isolates with reduced susceptibility was 50% for MQ, 22% for CQ, 12% for DOX, 6% for both QN and MDAQ and 1% for the drugs LMF and DHA. The highest significant positive correlations were shown between responses to CQ and MDAQ (r = 0.569; P < 0.0001), LMF and QN (r = 0.511; P < 0.0001), LMF and DHA (r = 0.428; P = 0.0001), LMF and MQ (r = 0.413; P = 0.0002), QN and DHA (r = 0.402; P = 0.0003) and QN and MQ (r = 0.421; P = 0.0001). Conclusions The introduction of ACT in 2002 has not induced a decrease in P. falciparum susceptibility to the drugs DHA, MDAQ and LMF, which are common ACT components. However, the prevalence of P. falciparum isolates with reduced susceptibility has increased for both MQ and DOX. Taken together, these data suggest that intensive surveillance of the P. falciparum in vitro susceptibility to anti-malarial drugs in Senegal is required. PMID

  19. Pfhrp2 and pfhrp3 polymorphisms in Plasmodium falciparum isolates from Dakar, Senegal: impact on rapid malaria diagnostic tests

    PubMed Central

    2013-01-01

    Background An accurate diagnosis is essential for the rapid and appropriate treatment of malaria. The accuracy of the histidine-rich protein 2 (PfHRP2)-based rapid diagnostic test (RDT) Palutop+4® was assessed here. One possible factor contributing to the failure to detect malaria by this test is the diversity of the parasite PfHRP2 antigens. Methods PfHRP2 detection with the Palutop+4® RDT was carried out. The pfhrp2 and pfhrp3 genes were amplified and sequenced from 136 isolates of Plasmodium falciparum that were collected in Dakar, Senegal from 2009 to 2011. The DNA sequences were determined and statistical analyses of the variation observed between these two genes were conducted. The potential impact of PfHRP2 and PfHRP3 sequence variation on malaria diagnosis was examined. Results Seven P. falciparum isolates (5.9% of the total isolates, regardless of the parasitaemia; 10.7% of the isolates with parasitaemia ≤0.005% or ≤250 parasites/μl) were undetected by the PfHRP2 Palutop+4® RDT. Low parasite density is not sufficient to explain the PfHRP2 detection failure. Three of these seven samples showed pfhrp2 deletion (2.4%). The pfhrp3 gene was deleted in 12.8%. Of the 122 PfHRP2 sequences, 120 unique sequences were identified. Of the 109 PfHRP3 sequences, 64 unique sequences were identified. Using the Baker’s regression model, at least 7.4% of the P. falciparum isolates in Dakar were likely to be undetected by PfHRP2 at a parasite density of ≤250 parasites/μl (slightly lower than the evaluated prevalence of 10.7%). This predictive prevalence increased significantly between 2009 and 2011 (P = 0.0046). Conclusion In the present work, 10.7% of the isolates with a parasitaemia ≤0.005% (≤250 parasites/μl) were undetected by the PfHRP2 Palutop+4® RDT (7.4% by the predictive Baker’model). In addition, all of the parasites with pfhrp2 deletion (2.4% of the total samples) and 2.1% of the parasites with parasitaemia >0.005% and presence of pfhrp2 were

  20. The effects of midwives’ job satisfaction on burnout, intention to quit and turnover: a longitudinal study in Senegal

    PubMed Central

    2012-01-01

    Background Despite working in a challenging environment plagued by persistent personnel shortages, public sector midwives in Senegal play a key role in tackling maternal mortality. A better understanding of how they are experiencing their work and how it is affecting them is needed in order to better address their needs and incite them to remain in their posts. This study aims to explore their job satisfaction and its effects on their burnout, intention to quit and professional mobility. Methods A cohort of 226 midwives from 22 hospitals across Senegal participated in this longitudinal study. Their job satisfaction was measured from December 2007 to February 2008 using a multifaceted instrument developed in West Africa. Three expected effects were measured two years later: burnout, intention to quit and turnover. Descriptive statistics were reported for the midwives who stayed and left their posts during the study period. A series of multiple regressions investigated the correlations between the nine facets of job satisfaction and each effect variable, while controlling for individual and institutional characteristics. Results Despite nearly two thirds (58.9%) of midwives reporting the intention to quit within a year (mainly to pursue new professional training), only 9% annual turnover was found in the study (41/226 over 2 years). Departures were largely voluntary (92%) and entirely domestic. Overall the midwives reported themselves moderately satisfied; least contented with their “remuneration” and “work environment” and most satisfied with the “morale” and “job security” facets of their work. On the three dimensions of the Maslach Burnout Inventory, very high levels of emotional exhaustion (80.0%) and depersonalization (57.8%) were reported, while levels of diminished personal accomplishment were low (12.4%). Burnout was identified in more than half of the sample (55%). Experiencing emotional exhaustion was inversely associated with

  1. Measurement of Health Program Equity Made Easier: Validation of a Simplified Asset Index Using Program Data From Honduras and Senegal

    PubMed Central

    Ergo, Alex; Ritter, Julie; Gwatkin, Davidson R; Binkin, Nancy

    2016-01-01

    ABSTRACT Equitable access to programs and health services is essential to achieving national and international health goals, but it is rarely assessed because of perceived measurement challenges. One of these challenges concerns the complexities of collecting the data needed to construct asset or wealth indices, which can involve asking as many as 40 survey questions, many with multiple responses. To determine whether the number of variables and questions could be reduced to a level low enough for more routine inclusion in evaluations and research without compromising programmatic conclusions, we used data from a program evaluation in Honduras that compared a pro-poor intervention with government clinic performance as well as data from a results-based financing project in Senegal. In both, the full Demographic and Health Survey (DHS) asset questionnaires had been used as part of the evaluations. Using the full DHS results as the “gold standard,” we examined the effect of retaining successively smaller numbers of variables on the classification of the program clients in wealth quintiles. Principal components analysis was used to identify those variables in each country that demonstrated minimal absolute factor loading values for 8 different thresholds, ranging from 0.05 to 0.70. Cohen’s kappa statistic was used to assess correlation. We found that the 111 asset variables and 41 questions in the Honduras DHS could be reduced to 9 variables, captured by only 8 survey questions (kappa statistic, 0.634), without substantially altering the wealth quintile distributions for either the pro-poor program or the government clinics or changing the resulting policy conclusions. In Senegal, the 103 asset variables and 36 questions could be reduced to 32 variables and 20 questions (kappa statistic, 0.882) while maintaining a consistent mix of users in each of the 2 lowest quintiles. Less than 60% of the asset variables in the 2 countries’ full DHS asset indices overlapped

  2. Measurement of Health Program Equity Made Easier: Validation of a Simplified Asset Index Using Program Data From Honduras and Senegal.

    PubMed

    Ergo, Alex; Ritter, Julie; Gwatkin, Davidson R; Binkin, Nancy

    2016-03-01

    Equitable access to programs and health services is essential to achieving national and international health goals, but it is rarely assessed because of perceived measurement challenges. One of these challenges concerns the complexities of collecting the data needed to construct asset or wealth indices, which can involve asking as many as 40 survey questions, many with multiple responses. To determine whether the number of variables and questions could be reduced to a level low enough for more routine inclusion in evaluations and research without compromising programmatic conclusions, we used data from a program evaluation in Honduras that compared a pro-poor intervention with government clinic performance as well as data from a results-based financing project in Senegal. In both, the full Demographic and Health Survey (DHS) asset questionnaires had been used as part of the evaluations. Using the full DHS results as the "gold standard," we examined the effect of retaining successively smaller numbers of variables on the classification of the program clients in wealth quintiles. Principal components analysis was used to identify those variables in each country that demonstrated minimal absolute factor loading values for 8 different thresholds, ranging from 0.05 to 0.70. Cohen's kappa statistic was used to assess correlation. We found that the 111 asset variables and 41 questions in the Honduras DHS could be reduced to 9 variables, captured by only 8 survey questions (kappa statistic, 0.634), without substantially altering the wealth quintile distributions for either the pro-poor program or the government clinics or changing the resulting policy conclusions. In Senegal, the 103 asset variables and 36 questions could be reduced to 32 variables and 20 questions (kappa statistic, 0.882) while maintaining a consistent mix of users in each of the 2 lowest quintiles. Less than 60% of the asset variables in the 2 countries' full DHS asset indices overlapped, and in none of

  3. Changes in Habitat Structure May Explain Decrease in Reintroduced Mohor Gazelle Population in the Guembeul Fauna Reserve, Senegal.

    PubMed

    Moreno, Eulalia; Sane, Abibou; Benzal, Jesús; Ibáñez, Belén; Sanz-Zuasti, Joaquín; Espeso, Gerardo

    2012-01-01

    Reintroduction is a widespread method for saving populations of endangered species from extinction. In spite of recent reviews, it is difficult to reach general conclusions about its value as a conservation tool, as authors are reluctant to publish unsuccessful results. The Mohor gazelle is a North African gazelle, extinct in the wild. Eight individuals were reintroduced in Senegal in 1984. The population grew progressively, albeit slowly, during the first 20 years after release, but then declined dramatically, until the population in 2009 was estimated at no more than 13-15 individuals. This study attempts to determine the likelihood of gazelle-habitat relationships to explain why the size of the gazelle population has diminished. Our results show that the Mohor gazelle in Guembeul is found in open habitats with less developed canopy where the grass is shorter, suggesting the possibility that changes in habitat structure have taken place during the time the gazelles have been in the Reserve, reducing the amount of suitable habitat. Reintroduction design usually concentrates on short-term factors that may affect survival of the released animals and their descendants (short-term achievement), while the key factors for assessing its success may be those that affect the long-term evolution of the population. PMID:26487026

  4. The Establishment of Marine Protected Areas in Senegal: Untangling the Interactions Between International Institutions and National Actors

    NASA Astrophysics Data System (ADS)

    Ferraro, Gianluca; Brans, Marleen; Dème, Moustapha; Failler, Pierre

    2011-04-01

    International institutions, understood as sets of rules contained in international agreements, are aimed at orienting national governments towards specific policy options. Nevertheless, they can determine a change in national policies and practices only if states are willing and capable of incorporating international obligations into their national legislations and ensuring their application and enforcement in areas that follow completely under national jurisdiction. The establishment of marine protected areas promoted by international agreements as a tool for the protection of marine resources represents an interesting case for revealing the complex interactions between international institutions and national actors. Particularly, the establishment of these areas in Senegal shows the salience of domestic constellations of actors who may support or undercut national commitments to international regimes: political elites, bureaucracies, the general public and target groups. By anchoring the empirical analysis to an actor-centred institutionalist perspective, the article explains how dynamic constellations of actors can distort the penetration of international objectives in the national policy framework. Different constellations of national actors can indeed bend international institutions at different moments: during the formulation of a new law in line with international obligations; in the definition of its implementation framework; and in the enforcement of national policies.

  5. Shift in species composition in the Anopheles gambiae complex after implementation of long-lasting insecticidal nets in Dielmo, Senegal.

    PubMed

    Sougoufara, S; Harry, M; Doucouré, S; Sembène, P M; Sokhna, C

    2016-09-01

    Long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) are the cornerstones of malaria vector control. However, the effectiveness of these control tools depends on vector ecology and behaviour, which also largely determine the efficacy of certain Anopheles mosquitoes (Diptera: Culicidae) as vectors. Malaria vectors in sub-Saharan Africa are primarily species of the Anopheles gambiae complex, which present intraspecific differences in behaviour that affect how they respond to vector control tools. The focus of this study is the change in species composition in the An. gambiae complex after the implementation of LLINs in Dielmo, Senegal. The main findings referred to dramatic decreases in the proportions of Anopheles coluzzii and An. gambiae after the introduction of LLINs, and an increase in the proportion of Anopheles arabiensis. Two years after LLINs were first introduced, An. arabiensis remained the most prevalent species and An. gambiae had begun to rebound. This indicated a need to develop additional vector control tools that can target the full range of malaria vectors. PMID:27058993

  6. Passive sampling devices enable capacity building and characterization of bioavailable pesticide along the Niger, Senegal and Bani Rivers of Africa.

    PubMed

    Anderson, Kim A; Seck, Dogo; Hobbie, Kevin A; Traore, Anna Ndiaye; McCartney, Melissa A; Ndaye, Adama; Forsberg, Norman D; Haigh, Theodore A; Sower, Gregory J

    2014-04-01

    It is difficult to assess pollution in remote areas of less-developed regions owing to the limited availability of energy, equipment, technology, trained personnel and other key resources. Passive sampling devices (PSDs) are technologically simple analytical tools that sequester and concentrate bioavailable organic contaminants from the environment. Scientists from Oregon State University and the Centre Régional de Recherches en Ecotoxicologie et de Sécurité Environnementale (CERES) in Senegal developed a partnership to build capacity at CERES and to develop a pesticide-monitoring project using PSDs. This engagement resulted in the development of a dynamic training process applicable to capacity-building programmes. The project culminated in a field and laboratory study where paired PSD samples were simultaneously analysed in African and US laboratories with quality control evaluation and traceability. The joint study included sampling from 63 sites across six western African countries, generating a 9000 data point pesticide database with virtual access to all study participants. PMID:24535398

  7. A new genus and two new species of lecanicephalidean tapeworms from the striped panray, Zanobatus schoenleinii (Rhinopristiformes: Zanobatidae), off Senegal.

    PubMed

    Jensen, Kirsten; Mojica, Kendra R; Caira, Janine N

    2014-10-01

    Recognised for their diversity in apical structure morphology, members of the cestode order Lecanicephalidea Wardle et McLeod, 1952 known to date exhibit relatively mundane and uniform acetabular morphology. A new lecanicephalidean genus, Zanobatocestus gen. n., is proposed for two new species found parasitising the spiral intestine of the striped panray, Zanobatus schoenleinii (Müller et Henle), off Senegal that are highly unusual in acetabular morphology. Unlike the members of the 21 recognised lecanicephalidean genera, which possess simple, uniloculate suckers or bothridia, Zanobatocestus minor sp. n. and Z. major sp. n. possess biloculate bothridia. The form of their apical structures and cocoons readily distinguish the two new species from one another. Zanobatocestus minor sp. n. exhibits an apical modification of the scolex proper that is narrow and elongated, an apical organ that is small and internal, and eggs in cocoons forming linear strands, whereas Z. major sp. n. exhibits an apical modification of the scolex proper that is wide and short, an apical organ that is extensive and primarily external, and eggs in cocoons primarily as doublets with bipolar filaments. Given the typically high host specificity of lecanicephalidean cestodes, as parasites of the only genus and species currently considered valid in the family Zanobatidae, Zanobatocestus gen. n. is likely to remain one of the less specious lecanicephalidean genera. PMID:25549499

  8. On the spatial coherence of rainfall over the Saloum delta (Senegal) from seasonal to decadal time scales

    NASA Astrophysics Data System (ADS)

    WADE, Malick; Mignot, Juliette; Lazar, Alban; Gaye, Amadou Thierno; Carré, Matthieu

    2015-06-01

    A paleoreconstruction of the length and intensity of the rainy season over western Africa has been recently proposed, using analysis of fossil mollusk shells from the Saloum delta region, in western Senegal. In order to evaluate the significance of local long-term reconstructions of precipitations from paleoclimate proxies, and to better characterize the spatial homogeneity of rainfall distribution in northern Africa, we analyze here the spatial representativeness of rainfall in this region, from seasonal to decadal timescales. The spatial coherence of winter episodic rainfall events is relatively low and limited to surrounding countries. On the other hand, the summer rainfall, associated with the West African Monsoon, shows extended spatial coherence. At seasonal timescales, local rainfall over the Saloum is significantly correlated with rainfall in the whole western half of the Sahel. At interannual and longer timescales, the spatial coherence extends as far as the Red Sea, covering the full Sahel region. This spatial coherence is mainly associated to the zonal extension of the Inter Tropical Convergence Zone. Coherently, summer rainfalls appear to be driven by SST anomalies mainly in the Pacific, the Indian Ocean, the Mediterranean basin, and the North Pacific. A more detailed analysis shows that consistency of the spatial rainfall coherence is reduced during the onset season of the West African Monsoon.

  9. The use of Jatropha curcas to achieve a self sufficient water distribution system: A case study in rural Senegal

    NASA Astrophysics Data System (ADS)

    Archer, Alexandra

    The use of Jatropha curcas as a source of oil for fueling water pumps holds promise for rural communities struggling to achieve water security in arid climates. The potential for use in developing communities as an affordable, sustainable fuel source has been highly recommended for many reasons: it is easily propagated, drought resistant, grows rapidly, and has high-oil-content seeds, as well as medicinal and economic potential. This study uses a rural community in Senegal, West Africa, and calculates at what level of Jatropha curcas production the village is able to be self-sufficient in fueling their water system to meet drinking, sanitation and irrigation requirements. The current water distribution system was modelled to represent irrigation requirements for nine different Jatropha curcas cultivation and processing schemes. It was found that a combination of using recycled greywater for irrigation and a mechanical press to maximize oil recovered from the seeds of mature Jatropha curcas trees, would be able to operate the water system with no diesel required.

  10. Rift Valley fever dynamics in Senegal: a project for pro-active adaptation and improvement of livestock raising management.

    PubMed

    Lafaye, Murielle; Sall, Baba; Ndiaye, Youssou; Vignolles, Cecile; Tourre, Yves M; Borchi, Franc Ois; Soubeyroux, Jean-Michel; Diallo, Mawlouth; Dia, Ibrahima; Ba, Yamar; Faye, Abdoulaye; Ba, Taibou; Ka, Alioune; Ndione, Jacques-André; Gauthier, Hélène; Lacaux, Jean-Pierre

    2013-11-01

    The multi-disciplinary French project "Adaptation à la Fiévre de la Vallée du Rift" (AdaptFVR) has concluded a 10-year constructive interaction between many scientists/partners involved with the Rift Valley fever (RVF) dynamics in Senegal. The three targeted objectives reached were (i) to produce--in near real-time--validated risk maps for parked livestock exposed to RVF mosquitoes/vectors bites; (ii) to assess the impacts on RVF vectors from climate variability at different time-scales including climate change; and (iii) to isolate processes improving local livestock management and animal health. Based on these results, concrete, pro-active adaptive actions were taken on site, which led to the establishment of a RVF early warning system (RVFews). Bulletins were released in a timely fashion during the project, tested and validated in close collaboration with the local populations, i.e. the primary users. Among the strategic, adaptive methods developed, conducted and evaluated in terms of cost/benefit analyses are the larvicide campaigns and the coupled bio-mathematical (hydrological and entomological) model technologies, which are being transferred to the staff of the "Centre de Suivi Ecologique" (CSE) in Dakar during 2013. Based on the results from the AdaptFVR project, other projects with similar conceptual and modelling approaches are currently being implemented, e.g. for urban and rural malaria and dengue in the French Antilles. PMID:24258902

  11. Climate impacts on environmental risks evaluated from space: a conceptual approach to the case of Rift Valley Fever in Senegal

    PubMed Central

    Tourre, Yves M.; Lacaux, Jean-Pierre; Vignolles, Cécile; Lafaye, Murielle

    2009-01-01

    Background Climate and environment vary across many spatio-temporal scales, including the concept of climate change, which impact on ecosystems, vector-borne diseases and public health worldwide. Objectives To develop a conceptual approach by mapping climatic and environmental conditions from space and studying their linkages with Rift Valley Fever (RVF) epidemics in Senegal. Design Ponds in which mosquitoes could thrive were identified from remote sensing using high-resolution SPOT-5 satellite images. Additional data on pond dynamics and rainfall events (obtained from the Tropical Rainfall Measuring Mission) were combined with hydrological in-situ data. Localisation of vulnerable hosts such as penned cattle (from QuickBird satellite) were also used. Results Dynamic spatio-temporal distribution of Aedes vexans density (one of the main RVF vectors) is based on the total rainfall amount and ponds’ dynamics. While Zones Potentially Occupied by Mosquitoes are mapped, detailed risk areas, i.e. zones where hazards and vulnerability occur, are expressed in percentages of areas where cattle are potentially exposed to mosquitoes’ bites. Conclusions This new conceptual approach, using precise remote-sensing techniques, simply relies upon rainfall distribution also evaluated from space. It is meant to contribute to the implementation of operational early warning systems for RVF based on both natural and anthropogenic climatic and environmental changes. In a climate change context, this approach could also be applied to other vector-borne diseases and places worldwide. PMID:20052381

  12. After the withdrawal of 'informed choice': the meanings and social effects of mothers' choice for HIV prevention in Senegal.

    PubMed

    Desclaux, Alice

    2014-01-01

    To prevent HIV transmission through breastfeeding, African health services in 1998 implemented the World Health Organization's approach of 'informed choice' when recommending infant feeding options to HIV-positive mothers. In 2010, 'informed choice' was withdrawn in favour of antiretroviral prophylaxis with breastfeeding. A 2010-11 ethnographic study conducted in Senegal among HIV-positive mothers revealed three broad responses to the withdrawal of choice and formula provision: 'resistance' from association members claiming the health system was responsible for providing formula to ensure efficient prevention; 'compliance' among mothers adopting 'protected breastfeeding' without complaints; and 'self-reliance' among women trying to obtain formula through other means without mentioning choice. These three responses shed light on the meanings attributed to choice and on the social impact of formula provision during the 'informed choice era.' The analysis shows that the top-down introduction of 'informed choice' as an ethical and management imperative was appropriated and re-signified locally, making space for new forms of sociality within medical and associative social spaces. These social forms could not easily be maintained after the withdrawal of formula provision; women who continue to exert choice do so silently. By focusing on the upheaval of social care arrangements after the introduction of prophylaxis by pharmaceuticals, this paper sheds light on the understudied local consequences of changes in public health policies and the social framing of 'choice' in low-income countries' health systems. PMID:24975228

  13. Water-poverty relationships in the coastal town of Mbour (Senegal): Relevance of GIS for decision support

    NASA Astrophysics Data System (ADS)

    Toure, Néné Makoya; Kane, Alioune; Noel, Jean François; Turmine, Vincent; Nedeff, Valentin; Lazar, Gabriel

    2012-02-01

    Coastal area is always a zone with complex problems. Due to the attraction they exert, are facing many social problems. Therefore, a coastal city is usually a city with problems. Its extension, caused by the influx of people from different backgrounds, creates an increased demand for services. One of the problems frequently encountered, especially in Senegal, is access to water. The problem of access to water is poorly treated, without being correlated with the urban evolution, i.e. with increasing population and demand growth. The water resource is facing numerous complications such as the lack of integrated management, integration issues at the governance level, where the local factor is often forgotten. The town of Mbour, object of our study, does not come out of that lot, being an attractive coastal city, from an African country. This indicates the need for an integrated management oriented from local to a global basis and not vice versa. The study presented in this paper indicates that a large proportion of the population has not access to a verified drinking water system and uses water from wells or standpipes. Half of the surveyed population (50%) has no access to a water supply system. The water poverty map of the town overlaps with that of the general poverty excepting few neighborhoods. This means that even areas that are not affected by poverty have a very low or poor access to water, which so far remains the perverse effect of the reform of the Senegalese water sector in 1995.

  14. [Mortality from snake bites, wild and domestic animal bites and arthropod stings in the savannah zone of eastern Senegal].

    PubMed

    Trape, J F; Pison, G; Guyavarch, E; Mane, Y

    2002-08-01

    From 1976 to 1999, we conducted a prospective study of overall and cause-specific mortality among the population of 42 villages of south-eastern Senegal. Of 4,228 deaths registered during this period, 26 were brought on by snakebites, 4 by invertebrate stings and 8 by other wild or domestic animals. The average annual mortality rate from snakebite was 14 deaths per 100,000 population. Among persons aged 1 year or more, 0.9% (26/2,880) of deaths were caused by snakebite and this cause represented 28% (26/94) of the total number of deaths by accident. We also investigated the snake fauna of the area. Of 1,280 snakes belonging to 34 species that were collected, one-third were dangerous and the proportion of Viperidae, Elapidae and Atractaspididae was 23%, 11% and 0.6%, respectively. The saw-scaled viper Echis ocellatus was the most abundant species (13.6%). Other venomous species were Causus maculatus (6.5%), Naja katiensis (5.5%), Bitis arietans (2.7%), Elapsoidea trapei (2.4%), Naja nigricollis (1.2%), Naja melanoleuca (1.1%), Atractaspis aterrima (0.4%), Dendroaspis polylepis (0.3%) and Naja haje (0.1%). PMID:12404858

  15. Host preferences and circadian rhythm of Culicoides (Diptera: Ceratopogonidae), vectors of African horse sickness and bluetongue viruses in Senegal.

    PubMed

    Fall, Moussa; Fall, Assane G; Seck, Momar T; Bouyer, Jérémy; Diarra, Maryam; Lancelot, Renaud; Gimonneau, Geoffrey; Garros, Claire; Bakhoum, Mame T; Faye, Ousmane; Baldet, Thierry; Balenghien, Thomas

    2015-09-01

    African horse sickness- and bluetongue virus are orbiviruses transmitted by Culicoides biting midges (Diptera: Ceratopogonidae) to horses and to ruminants, respectively. Since the last epizootic outbreak of African horse sickness in 2007 in Senegal, extensive investigations have been undertaken to improve our knowledge on Culicoides species involved locally in the transmission of the virus. The purpose of this study was to compare and quantify the host preferences of potential vectors of these orbiviruses on horse and sheep and to study their circadian rhythm. We found that Culicoides oxystoma and species of the sub-genus Avaritia (Culicoides imicola, Culicoides bolitinos and Culicoides pseudopallidipennis) had a preference for horse when compared to sheep (the predicted ratio between horse and sheep was 80 for C. oxystoma and 26 for C. imicola), and were mostly crepuscular: C. oxystoma had continuous activity throughout the diel with peaks in numbers collected after sunrise and sunset, while C. imicola was mostly nocturnal with peak after sunset. Unexpectedly, species of the subgenus Lasiohelea was also collected during this study. This diurnal biting species was a nuisance pest for both animal species used as bait. PMID:26099680

  16. Using species distribution models to optimize vector control in the framework of the tsetse eradication campaign in Senegal

    PubMed Central

    Dicko, Ahmadou H.; Lancelot, Renaud; Seck, Momar T.; Guerrini, Laure; Sall, Baba; Lo, Mbargou; Vreysen, Marc J. B.; Lefrançois, Thierry; Fonta, William M.; Peck, Steven L.; Bouyer, Jérémy

    2014-01-01

    Tsetse flies are vectors of human and animal trypanosomoses in sub-Saharan Africa and are the target of the Pan African Tsetse and Trypanosomiasis Eradication Campaign (PATTEC). Glossina palpalis gambiensis (Diptera: Glossinidae) is a riverine species that is still present as an isolated metapopulation in the Niayes area of Senegal. It is targeted by a national eradication campaign combining a population reduction phase based on insecticide-treated targets (ITTs) and cattle and an eradication phase based on the sterile insect technique. In this study, we used species distribution models to optimize control operations. We compared the probability of the presence of G. p. gambiensis and habitat suitability using a regularized logistic regression and Maxent, respectively. Both models performed well, with an area under the curve of 0.89 and 0.92, respectively. Only the Maxent model predicted an expert-based classification of landscapes correctly. Maxent predictions were therefore used throughout the eradication campaign in the Niayes to make control operations more efficient in terms of deployment of ITTs, release density of sterile males, and location of monitoring traps used to assess program progress. We discuss how the models’ results informed about the particular ecology of tsetse in the target area. Maxent predictions allowed optimizing efficiency and cost within our project, and might be useful for other tsetse control campaigns in the framework of the PATTEC and, more generally, other vector or insect pest control programs. PMID:24982143

  17. Passive sampling devices enable capacity building and characterization of bioavailable pesticide along the Niger, Senegal and Bani Rivers of Africa

    PubMed Central

    Anderson, Kim A.; Seck, Dogo; Hobbie, Kevin A.; Traore, Anna Ndiaye; McCartney, Melissa A.; Ndaye, Adama; Forsberg, Norman D.; Haigh, Theodore A.; Sower, Gregory J.

    2014-01-01

    It is difficult to assess pollution in remote areas of less-developed regions owing to the limited availability of energy, equipment, technology, trained personnel and other key resources. Passive sampling devices (PSDs) are technologically simple analytical tools that sequester and concentrate bioavailable organic contaminants from the environment. Scientists from Oregon State University and the Centre Régional de Recherches en Ecotoxicologie et de Sécurité Environnementale (CERES) in Senegal developed a partnership to build capacity at CERES and to develop a pesticide-monitoring project using PSDs. This engagement resulted in the development of a dynamic training process applicable to capacity-building programmes. The project culminated in a field and laboratory study where paired PSD samples were simultaneously analysed in African and US laboratories with quality control evaluation and traceability. The joint study included sampling from 63 sites across six western African countries, generating a 9000 data point pesticide database with virtual access to all study participants. PMID:24535398

  18. [Living the aging in Senegal Perceptions/representations and coping strategies of persons of age three: results of investigations retrospective].

    PubMed

    Kâ, Ousseynou; Faye, Atoumane; Mbaye, El Hadji; Tall, Alioune Badara; Gaye, Awa; Sow, Papa Gallo; Ba, Cheikh Tidiane

    2016-03-01

    In Senegal, due to the young age of the population (60%) the concerns of the old tend to be put in the background. And yet, problems related to old age are a reality. These problems come up not in terms of demography (the old represent only 4.7% of the population), but in terms of the breaking-up of the social fabric, urbanization and the dismantling of the solidarity and poverty networks. This work is based on a collection of qualitative data from three studies conducted between 2008 and 2011 with the elderly to assess their real- life experiences, their perception of aging, their challenges and coping strategies. The results showed a transformation in the role and status of the old; this transformation being caused by social and society-related mutations. As a result, the inter-generation solidarity links have much loosened in the urban areas making the old people more vulnerable (in economic, social, health terms), especially those in charge of a family. The situation has been made worse by the unemployment affecting their offspring. In addition, the old people, who are often suffering from chronic diseases, find it hard to take charge of their medical expenses, despite the institution of the National Sesame Health Plan for the old or free health care policy. This has made them even more vulnerable. Yet before this precarious situation, the elderly develop strategies to cope with difficulties. Some recommendations have been made with a view to improving their lives and socioeconomic condition. PMID:26852947

  19. Effectiveness of a community-based intervention to improve nutrition in young children in Senegal: a difference in difference analysis.

    PubMed

    Alderman, Harold; Ndiaye, Biram; Linnemayr, Sebastian; Ka, Abdoulaye; Rokx, Claudia; Dieng, Khadidiatou; Mulder-Sibanda, Menno

    2009-05-01

    There are few studies of community growth promotion as a means of addressing malnutrition that are based on longitudinal analysis of large-scale programmes with adequate controls to construct a counterfactual. The current study uses a difference in difference comparison of cohorts to assess the impact on the proportion of underweight children who lived in villages receiving services provided by the Senegal Nutrition Enhancement Project between 2004 and 2006. The project, designed to extend nutrition and growth promotion intervention into rural areas through non-governmental organisation service providers, significantly lowered the risk of a child having a weight more than 2 sd below international norms. The odds ratio of being underweight for children in programme villages after introduction of the intervention was 0.83 (95% CI 0.686, 1.000), after controlling for regional trends and village and household characteristics. Most measured aspects of health care and health seeking behaviour improved in the treatment relative to the control. PMID:18559130

  20. Rift Valley fever in a zone potentially occupied by Aedes vexans in Senegal: dynamics and risk mapping

    NASA Astrophysics Data System (ADS)

    Tourre, Y. M.; Vignolles, C.; Lacaux, J.-P.; Bigeard, G.; Ndione, J.-A.; Lafaye, M.

    2009-09-01

    This paper presents an analysis of the interaction between the various variables associated with Rift Valley fever (RVF) such as the mosquito vector, available hosts and rainfall distribution. To that end, the varying zones potentially occupied by mosquitoes (ZPOM), rainfall events and pond dynamics, and the associated exposure of hosts to the RVF virus by Aedes vexans, were analyzed in the Barkedji area of the Ferlo, Senegal, during the 2003 rainy season. Ponds were identified by remote sensing using a high-resolution SPOT-5 satellite image. Additional data on ponds and rainfall events from the Tropical Rainfall Measuring Mission were combined with in-situ entomological and limnimetric measurements, and the localization of vulnerable ruminant hosts (data derived from QuickBird satellite). Since "Ae. vexans productive events” are dependent on the timing of rainfall for their embryogenesis (six days without rain are necessary to trigger hatching), the dynamic spatio-temporal distribution of Ae. vexans density was based on the total rainfall amount and pond dynamics. Detailed ZPOM mapping was obtained on a daily basis and combined with aggressiveness temporal profiles. Risks zones, i.e. zones where hazards and vulnerability are combined, are expressed by the percentages of parks where animals are potentially exposed to mosquito bites. This new approach, simply relying upon rainfall distribution evaluated from space, is meant to contribute to the implementation of a new, operational early warning system for RVF based on environmental risks linked to climatic and environmental conditions.

  1. Wetting and energetics of solid Au and Au-Ge/SiC interfaces

    SciTech Connect

    Wang, Z.; Wynblatt, P.

    1998-09-01

    A solid state wetting technique has been used to investigate the effects of alloying Au with Ge on the wetting and energetics of Au/SiC interfaces at 1123 K. Germanium was found to segregate to the Au/SiC interface, thereby lowering the contact angle of Au on SiC from 133 to 110, and doubling the work of adhesion of Au on SiC. Calculations based on a monolayer model predict a segregation of 0.89 monolayers of Ge at the Au/SiC interface for Au containing 2.3 at.% Ge. This agrees reasonably well with a coverage of 0.6 monolayers Ge at the Au/SiC interface obtained by direct measurements based on the crater edge profiling technique. The work also demonstrates that simple models of interfacial composition can be combined with the Gibbs adsorption isotherm to provide reliable estimates of interfacial composition at complex four-component interfaces.

  2. Gold nanowired: a linear (Au25)(n) polymer from Au25 molecular clusters.

    PubMed

    De Nardi, Marco; Antonello, Sabrina; Jiang, De-en; Pan, Fangfang; Rissanen, Kari; Ruzzi, Marco; Venzo, Alfonso; Zoleo, Alfonso; Maran, Flavio

    2014-08-26

    Au25(SR)18 has provided fundamental insights into the properties of clusters protected by monolayers of thiolated ligands (SR). Because of its ultrasmall core, 1 nm, Au25(SR)18 displays molecular behavior. We prepared a Au25 cluster capped by n-butanethiolates (SBu), obtained its structure by single-crystal X-ray crystallography, and studied its properties both experimentally and theoretically. Whereas in solution Au25(SBu)18(0) is a paramagnetic molecule, in the crystal it becomes a linear polymer of Au25 clusters connected via single Au-Au bonds and stabilized by proper orientation of clusters and interdigitation of ligands. At low temperature, [Au25(SBu)18(0)]n has a nonmagnetic ground state and can be described as a one-dimensional antiferromagnetic system. These findings provide a breakthrough into the properties and possible solid-state applications of molecular gold nanowires. PMID:25088331

  3. Pt{sub 3}Au and PtAu clusters: Electronic states and potential energy surfaces

    SciTech Connect

    Dai, D.; Balasubramanian, K.

    1994-03-15

    We carried out complete active space multiconfiguration self-consistent-field calculations followed by multireference singles+doubles configuration interaction with the Davidson correction which included up to 3.55 million configurations employing relativistic effective core potentials on Pt{sub 3}+Au and PtAu clusters. Four low-lying electronic states were identified for Pt{sub 3}+Au. The {sup 2}{ital A}{sub 2} electronic state ({ital C}{sub 3{ital v}}) was found to be the ground state of Pt{sub 3}Au. Spin--orbit effects were found to be significant. We also computed six low-lying electronic states of PtAu and four low-lying electronic states of PtAu{sup +}. The 5/2 ({sup 2}{Delta}) and 0{sup +}({sup 1}{Sigma}{sup +}) states were found to be the ground states of PtAu and PtAu{sup +}, respectively.

  4. Interplanetary dust between 1 and 5 AU

    NASA Technical Reports Server (NTRS)

    Stanley, J. E.; Singer, S. F.; Alvarez, J. M.

    1979-01-01

    Analyses of data from the Meteoroid Detection Experiment (MDE) and the Imaging Photopolarimeter (IPP) aboard Pioneer 10 and 11 have led to contradictory conclusions. While the MDE indicates a significant particle environment in the outer solar system (out to at least 5 AU), the IPP sees no zodiacal light (therefore implying no small particles) past 3.3 AU. These two results are reconciled by noting that the spectral index p (relating particle radius and particle concentration) is not a constant in the solar system but changes from less than 2 near 1 AU to more than 2.5 at 5 AU for particles in the range of 10 microns.

  5. Bright, NIR-emitting Au23 from Au25: characterization and applications including biolabeling.

    PubMed

    Muhammed, Madathumpady Abubaker Habeeb; Verma, Pramod Kumar; Pal, Samir Kumar; Kumar, R C Arun; Paul, Soumya; Omkumar, Ramakrishnapillai Vyomakesannair; Pradeep, Thalappil

    2009-10-01

    A novel interfacial route has been developed for the synthesis of a bright-red-emitting new subnanocluster, Au(23), by the core etching of a widely explored and more stable cluster, Au(25)SG(18) (in which SG is glutathione thiolate). A slight modification of this procedure results in the formation of two other known subnanoclusters, Au(22) and Au(33). Whereas Au(22) and Au(23) are water soluble and brightly fluorescent with quantum yields of 2.5 and 1.3 %, respectively, Au(33) is organic soluble and less fluorescent, with a quantum yield of 0.1 %. Au(23) exhibits quenching of fluorescence selectively in the presence of Cu(2+) ions and it can therefore be used as a metal-ion sensor. Aqueous- to organic-phase transfer of Au(23) has been carried out with fluorescence enhancement. Solvent dependency on the fluorescence of Au(23) before and after phase transfer has been studied extensively and the quantum yield of the cluster varies with the solvent used. The temperature response of Au(23) emission has been demonstrated. The inherent fluorescence of Au(23) was used for imaging human hepatoma cells by employing the avidin-biotin interaction. PMID:19711391

  6. The Electronic Properties and L3 XANES of Au and Nano-Au

    SciTech Connect

    Yiu, Y.M.; Zhang, P.; Sham, T.K.

    2004-04-20

    The electronic properties of Au crystal and nano Au have been investigated by theory and experiment. Molecularly capped nano-Au was synthesized using the two-phase method. Au nano-particles have been characterized by X-Ray Diffraction (XRD) and Transmission Electron Microscopy (TEM). They retain the fcc crystal structure. Their sizes have been determined to be in a range from 5.5 nm to 1.7 nm. The L3 X-ray Absorption Near Edge Structure (XANES) of nano-Au and Au foil have been recorded using synchrotron radiation, and examined by theoretical calculation based on the first principles. Both theory and experiment show that the nano-Au particles have essentially all the Au L3 XANES features of bulk Au in the near edge region with less pronounced resonance peaks. It is also shown that nano Au exhibits lower 4f binding energy than bulk Au in good agreement with quantum confined Au systems reported previously.

  7. Au nanorod helical superstructures with designed chirality.

    PubMed

    Lan, Xiang; Lu, Xuxing; Shen, Chenqi; Ke, Yonggang; Ni, Weihai; Wang, Qiangbin

    2015-01-14

    A great challenge for nanotechnology is to controllably organize anisotropic nanomaterials into well-defined three-dimensional superstructures with customized properties. Here we successfully constructed anisotropic Au nanorod (AuNR) helical superstructures (helices) with tailored chirality in a programmable manner. By designing the 'X' pattern of the arrangement of DNA capturing strands (15nt) on both sides of a two-dimensional DNA origami template, AuNRs functionalized with the complementary DNA sequences were positioned on the origami and were assembled into AuNR helices with the origami intercalated between neighboring AuNRs. Left-handed (LH) and right-handed (RH) AuNR helices were conveniently accomplished by solely tuning the mirrored-symmetric 'X' patterns of capturing strands on the origami. The inter-rod distance was precisely defined as 14 nm and inter-rod angle as 45°, thus a full helix contains 9 AuNRs with its length up to about 220 nm. By changing the AuNR/origami molar ratio in the assembly system, the average number of AuNR in the helices was tuned from 2 to 4 and 9. Intense chiroptical activities arose from the longest AuNR helices with a maximum anisotropy factor of ∼0.02, which is highly comparable to the reported macroscopic AuNR assemblies. We expect that our strategy of origami templated assembly of anisotropic chiral superstructures would inspire the bottom-up fabrication of optically active nanostructures and shed light on a variety of applications, such as chiral fluids, chiral signal amplification, and fluorescence combined chiral spectroscopy. PMID:25516475

  8. Tangafric: a software for the estimation of textural and hydraulic properties in shallow aquifers from well logs in Senegal and Guinea

    NASA Astrophysics Data System (ADS)

    Fussi, Fabio; Bonomi, Tullia; Fava, Francesco; Hamidou, Barry; Hamidou Khane, Cheikh; Faye, Gayane; Wade, Souleye; Colombo, Roberto

    2014-05-01

    Background In order to increase access to drinking water in Africa there is more and more interest in the promotion of manual drilling techniques, without need of expensive drilling equipment, but they can be applied only in those areas with suitable hydrogeological conditions: thick layers of unconsolidated sediments and shallow groundwater level. Mapping of suitable zones for manual drilling at national level in Africa is a crucial activity and local institutions and UNICEF are implementing specific programs for its promotion, but the limitation in available data concerning shallow hydrogeological aquifers are limited. The research has been developed in the project "Use of remote sensing and terrain modeling to identify suitable zones for manual drilling in Africa and support low cost water supply", within the scientific cooperation between the University of Milano-Bicocca, Universite' Cheick Anta Diop (Dakar Senegal) , SNAPE - Service Nationale de Points d'Eau (Conakry Guinea), UNICEF Senegal and UNICEF Guinea. The project is funded by NERC (National Environmental Research Council, UK). Objective of the research: The presented work is only the starting point of the project aiming to elaborate an automatic procedures to manage and improve the existing database of borehole logs in Senegal and Guinea for the interpretation of shallow hydrogeological conditions and identification of suitable zones for manual drilling, in two pilot areas: Louga (Northwestern Senegal) and Faranah/Kankan (Eastern Guinea). Within the objective of the project is also considered the integration of Remote Sensing to support hydrogeological interpretation, especially where borehole logs are not present. Methodology Focus is to create a hydrogeological database, TANGAFRIC, to organize, codify and elaborate hydrogeological data. The metodology derives from the software TANGRAM (www.tangram.samit.unimib.it) produced by the University of Milano Bicocca, with innovative aspect of stratigraphic

  9. Oxygen-assisted reduction of Au species on Au/SiO2 catalyst in room temperature CO oxidation

    SciTech Connect

    Wu, Zili; Zhou, Shenghu; Zhu, Haoguo; Dai, Sheng; Overbury, Steven {Steve} H

    2008-01-01

    An unexpected oxygen-assisted reduction of cationic Au species by CO was found on a Au/SiO2 catalyst at room temperature; CO oxidation activity increases simultaneously with the reduction of Au species, suggesting the key role of metallic Au played in CO oxidation on Au/SiO2.

  10. Projected impact of climate change in the hydroclimatology of Senegal with a focus over the Lake of Guiers for the twenty-first century

    NASA Astrophysics Data System (ADS)

    Tall, Moustapha; Sylla, Mouhamadou Bamba; Diallo, Ismaïla; Pal, Jeremy S.; Faye, Aïssatou; Mbaye, Mamadou Lamine; Gaye, Amadou Thierno

    2016-04-01

    This study analyzes the impact of anthropogenic climate change in the hydroclimatology of Senegal with a focus over the lake of Guiers basin for the middle (2041-2060) and late twenty-first century (2080-2099). To this end, high-resolution multimodel ensemble based on regional climate model experiments considering two Representative Concentration Pathways (RCP4.5 and RCP8.5) is used. The results indicate that an elevated warming, leading to substantial increase of atmospheric water demand, is projected over the whole of Senegal. In the Lake basin, these increases in potential evapotranspiration (PE) range between 10 and 25 % in the near future and for RCP4.5 while for the far future and RCP8.5, they exceed 50 %. In addition, mean precipitation unveils contrasting changes with wetter (10 to 25 % more) conditions by the middle of the century and drier conditions (more than 50 %) during the late twenty-first century. Such changes cause more/less evapotranspiration and soil moisture respectively during the two future periods. Furthermore, surface runoff shows a tendency to increase in most areas amid few locations including the Lake basin with substantial reduction. Finally, it is found that while semi-arid climates develop in the RCP4.5 scenario, generalized arid conditions prevail over the whole Senegal for RCP8.5. It is thus evident that these future climate conditions substantially threaten freshwater availability for the country and irrigated cropping over the Lake basin. Therefore, strong governmental politics are needed to help design response options to cope with the challenges posed by the projected climate change for the country.

  11. Diagnostic Accuracy of a Prototype Point-of-Care Test for Ocular Chlamydia trachomatis under Field Conditions in The Gambia and Senegal

    PubMed Central

    Harding-Esch, Emma M.; Holland, Martin J.; Schémann, Jean-François; Molina, Sandra; Sarr, Isatou; Andreasen, Aura A.; Roberts, Chrissy h.; Sillah, Ansumana; Sarr, Boubacar; Harding, Edward F.; Edwards, Tansy; Bailey, Robin L.; Mabey, David C. W.

    2011-01-01

    Background The clinical signs of active trachoma are often present in the absence of ocular Chlamydia trachomatis infection in low prevalence and mass treated settings. Treatment decisions are currently based on the prevalence of clinical signs, and this may result in the unnecessary distribution of mass antibiotic treatment. We aimed to evaluate the diagnostic accuracy of a prototype point-of-care (POC) test, developed for field diagnosis of ocular C. trachomatis, in low prevalence settings of The Gambia and Senegal. Methodology/Principal Findings Three studies were conducted, two in The Gambia and one in Senegal. Children under the age of 10 years were screened for the clinical signs of trachoma. Two ocular swabs were taken from the right eye. The first swab was tested by the POC test in the field and the result independently graded by two readers. The second swab was tested for the presence of C. trachomatis by Amplicor Polymerase Chain Reaction. In Senegal, measurements of humidity and temperature in the field were taken. A total of 3734 children were screened, 950 in the first and 1171 in the second Gambian study, and 1613 in Senegal. The sensitivity of the prototype POC test ranged between 33.3–67.9%, the specificity between 92.4–99.0%, the positive predictive value between 4.3–21.0%, and the negative predictive value between 98.0–99.8%. The rate of false-positives increased markedly at temperatures above 31.4°C and relative humidities below 11.4%. Conclusions/Significance In its present format, this prototype POC test is not suitable for field diagnosis of ocular C. trachomatis as its specificity decreases in hot and dry conditions: the environment in which trachoma is predominantly found. In the absence of a suitable test for infection, trachoma diagnosis remains dependent on clinical signs. Under current WHO recommendations, this is likely resulting in the continued mass treatment of non-infected communities. PMID:21829735

  12. [(CF3)4Au2(C5H5N)2]--a new alkyl gold(II) derivative with a very short Au-Au bond.

    PubMed

    Zopes, David; Hegemann, Corinna; Tyrra, Wieland; Mathur, Sanjay

    2012-09-11

    A new gold(II) species [(CF(3))(4)Au(2)(C(5)H(5)N)(2)] with a very short unsupported Au-Au bond (250.62(9) pm) was generated by photo irradiation of a silver aurate, [Ag(Py)(2)][Au(CF(3))(2)], unambiguously characterized by (19)F and (109)Ag NMR studies. PMID:22836874

  13. Estuarine resources use by juvenile Flagfin mojarra ( Eucinostomus melanopterus) in an inverse tropical estuary (Sine Saloum, Senegal)

    NASA Astrophysics Data System (ADS)

    Gning, Ndombour; Le Loc'h, François; Thiaw, Omar T.; Aliaume, Catherine; Vidy, Guy

    2010-03-01

    The Flagfin mojarra, Eucinostomus melanopterus, is a marine spawner whose young individuals are common in the Sine Saloum inverse estuary (Senegal). The species offers the opportunity to study both the use of the estuarine nursery resources and the impact of the particular environment of the inverse estuary on these resources. This will lead to a better understanding of the functioning of the nursery. We investigated the resources used by juvenile Flagfin mojarra by coupling stomach contents and stable isotopes methods. Young Flagfin mojarra feed on a wide range of invertebrates. Diet changed from copepods in the smallest size class (10-40 mm), to a range of invertebrates including amphipods, insect larvae, polychaetes and mollusc in the medium size class (up to 60 mm) and mainly polychaetes for individuals >60 mm in size. In mangrove habitats with moderate salinity, the diet was dominated by polychaetes and decapod larvae (crabs) whereas in habitats with higher salinity, diet was dominated by amphipods. In very hypersaline areas with scarce mangroves, diet comprised benthic copepods, chironomid larvae and ostracods. This agreed with a clear change in δ13C measured in fish sampled at downstream or upstream sites. Comparison with signatures of primary producers suggested that the local food web exploited by young Flagfin mojarra is mainly based on phytoplankton in the downstream mangrove area, and mainly on benthic microalgae in the upstream hypersaline area. As in many studies considering the food webs in mangrove, mangrove was not identified as a major contributor to the food web exploited by E. melanopterus. This needs further investigation particularly because the exportation of estuarine materials to the sea is limited in an inverse estuary.

  14. [Variability of diarrheal diseases in children under 5 living in an urban setting: observations in Rufisque, Senegal].

    PubMed

    Sy, I; Handschumacher, P; Wyss, K; Cisse, G; Lo, B; Piermay, J L; Tanner, M

    2010-02-01

    Rapid urbanization has created numerous health risks in developing countries, but the exact impact on many diseases in function of living conditions is unclear. For insight into this complex relationship, a study on diarrheal diseases was carried out to obtain knowledge about the distribution of health risks in an urban setting. An epidemiological survey with a combined longitudinal and transverse design was conducted in Rufisque, Senegal, from April 2002 to March 2003 in a sample including households with children less than 5-years-old living in four areas presenting different levels of hygiene. Results showed a high overall incidence of diarrhea (6.5 episodes/child/year) but there were major discrepancies between the four study areas in direct relation with level of hygiene. The annual incidence per child was lower in the low-cost housing project (fair hygiene, 3.4 episodes) than in the Castors area (poor hygiene, 6.8 episodes), Diokoul Wague area (very poor hygiene, 7.3 episodes) and Goufe Aldiana area (no hygiene, 8.4 episodes). The study showed only a slight seasonal effect on diarrheal disease in the different areas. However, the differences observed between areas during the cold and hot dry seasons were considerably attenuated in the rainy season. This variability in the incidence rate that underlines the diversity of urban living conditions depends on a variety of risk factors (such as age and number of children) that may interact, although hygiene level remains critical. For issues usually given priority at the national level, multiplying studies aimed at fine analysis of factors underlying disease transmission is useful since this approach can improve understanding of public health policy in city environments characterized by the complex conditions (density and diversity) created by urbanization. PMID:20337117

  15. The Framework Convention on Global Health: A tool for empowering the HIV/AIDS movements in Senegal and South Africa.

    PubMed

    Scheepers, Ella

    2013-01-01

    Despite the Alma Ata-inspired slogan "health for all by 2000," the world remains afflicted with poor health in the second decade of the 21st century.1 This situation has generated much debate, and as a result, national and global responses have arguably entered a new era, building on the past success and failures of health movements, most notably on the back of the global HIV/AIDS movement. This article aims to contribute to the existing knowledge around a Framework Convention on Global Health (FCGH) from the perspective that any international legal framework conceptualisation on the right to health must involve those whose health is at stake. In order to achieve this analyses of the role played by civil society, who aim to give a voice to those unheard in the halls of state power, are vital for any discussion around the international right to health framework. The two case studies, Senegal and South Africa, were used to look at the current status of the international right to health framework, specifically in the context of the civil society's role in combating the HIV/AIDS epidemic. Through this, the article explores the possible role of an FCGH in empowering the HIV/AIDS movements in the protection and promotion of the right to health in Africa. The findings discerned that African states face different challenges regarding the realization of the right to health in the context of HIV/AIDS. However, the important role played by civil society in this realization is highlighted in both cases. They emphasize the diverse roles that an FCGH could play in empowering civil society, through the formulation of a global standard and framework on the right to health, in the form of an FCGH, particularly if it is as a result of a movement of rights education and advocacy from below. PMID:25006094

  16. Identifying landscape features associated with Rift Valley fever virus transmission, Ferlo region, Senegal, using very high spatial resolution satellite imagery

    PubMed Central

    2013-01-01

    Introduction Dynamics of most of vector-borne diseases are strongly linked to global and local environmental changes. Landscape changes are indicators of human activities or natural processes that are likely to modify the ecology of the diseases. Here, a landscape approach developed at a local scale is proposed for extracting mosquito favourable biotopes, and for testing ecological parameters when identifying risk areas of Rift Valley fever (RVF) transmission. The study was carried out around Barkedji village, Ferlo region, Senegal. Methods In order to test whether pond characteristics may influence the density and the dispersal behaviour of RVF vectors, and thus the spatial variation in RVFV transmission, we used a very high spatial resolution remote sensing image (2.4 m resolution) provided by the Quickbird sensor to produce a detailed land-cover map of the study area. Based on knowledge of vector and disease ecology, seven landscape attributes were defined at the pond level and computed from the land-cover map. Then, the relationships between landscape attributes and RVF serologic incidence rates in small ruminants were analyzed through a beta-binomial regression. Finally, the best statistical model according to the Akaike Information Criterion corrected for small samples (AICC), was used to map areas at risk for RVF. Results Among the derived landscape variables, the vegetation density index (VDI) computed within a 500 m buffer around ponds was positively correlated with serologic incidence (p<0.001), suggesting that the risk of RVF transmission was higher in the vicinity of ponds surrounded by a dense vegetation cover. The final risk map of RVF transmission displays a heterogeneous spatial distribution, corroborating previous findings from the same area. Conclusions Our results highlight the potential of very high spatial resolution remote sensing data for identifying environmental risk factors and mapping RVF risk areas at a local scale. PMID:23452759

  17. Environmental surveillance of poliovirus and non-polio enterovirus in urban sewage in Dakar, Senegal (2007-2013)

    PubMed Central

    Ndiaye, Abdou Kader; Diop, Pape Amadou Mbathio; Diop, Ousmane Madiagne

    2014-01-01

    Introduction Global poliomyelitis eradication initiative relies on (i) laboratory based surveillance of acute flaccid surveillance (AFP) to monitor the circulation of wild poliovirus in a population, and (ii) vaccination to prevent its diffusion. However, as poliovirus can survive in the environment namely in sewage, environmental surveillance (ES) is of growing importance as the eradication target is close. This study aimed to assess polioviruses and non polio enteroviruses circulation in sewage drains covering a significant population of Dakar. Methods From April 2007 to May 2013, 271 specimens of raw sewage were collected using the grab method in 6 neighborhoods of Dakar. Samples were processed to extract and concentrate viruses using polyethylene glycol and Dextran (two-phase separation method). Isolation of enteroviruses was attempted in RD, L20B and Hep2 cell lines. Polioviruses were identified by RT-PCR and Elisa. Non Polio Enteroviruses (NPEVs) were identified by RT-PCR and microneutralisation tests. Results Polioviruses and NPEVs were respectively detected in 34,3% and 42,8% sewage samples. No wild poliovirus neither circulating vaccine-derived Poliovirus (cVDPV) was detected. Neutralization assays have identified 49 non polio enteroviruses that were subsequently classified in 13 serotypes belonging to HEV-A (22, 4%), HEV-B (12, 24%), HEV-C (26, 53%) and HEV-D (6, 12%) species. Conclusion This study is the first documentation of enteroviruses environmental detection in Senegal. It shows the usefulness of environmental surveillance for indirect monitoring of the circulation and distribution of enteroviruses in the community. PMID:25848458

  18. The influence of natural and anthropogenic factors on mangrove dynamics over 60 years: The Somone Estuary, Senegal

    NASA Astrophysics Data System (ADS)

    Sakho, Issa; Mesnage, Valérie; Deloffre, Julien; Lafite, Robert; Niang, Isabelle; Faye, Guilgane

    2011-07-01

    Although such ecosystems are fragile, this study shows that the anthropogenic damages inflicted on the mangrove forests of West Africa can be reversed over a relatively short time period if environmental conditions are favorable. The mangrove ecosystem of the microtidal Somone Estuary, Senegal, has undergone extreme changes during the last century. The area occupied by mangrove forest was estimated with a diachronic study by GIS for the period 1946-2006. Between 1946 and 1978, 85% of the area was progressively replaced by unvegetated mudflats in the intertidal zones and by barren area in the supratidal zones. Until 1990, this was mainly a result of traditional wood harvesting. The impact was exacerbated by the closing off of the estuary to the sea (1967-1969 and 1987) and by an extended drought (1970 onwards), which resulted in a lack of renewal of water, hypersalinization and acidification. The main factors controlling mangrove evolution in the Somone ecosystem, however, are anthropogenic. Until 1990, traditional wood cutting (for wood and oyster harvesting) was practiced by the local population. Between 1978 and 1989, a small area occupied by the mangroves was stabilized. Since 1992, a modification of mangrove logging and a new reforestation policy resulted in an exponential increase of mangrove area progressively replacing intertidal mudflats. Such success in the restoration of the ecosystem reforestation is supported by favorable environmental conditions: tidal flooding, groundwater influence, rainfall during the wet season, low net accretion rate of about 0.2-0.3 cm year -1, and a ban on the cutting of mangrove wood. The rate of mangrove loss from 1946 to 1978 was 44,000 m 2 year -1, but this has been offset by restoration efforts resulting in an increase in mangrove area from 1992 to 2006 of 63,000 m 2 year -1.

  19. Crop Water Stress Reduction Due to The Effects of Native Woody Shrubs in the Peanut Basin, Senegal

    NASA Astrophysics Data System (ADS)

    Bogie, N. A.; Bayala, R.; Burns, A.; Diedhiou, I.; Ghezzehei, T. A.; Dick, R.

    2013-12-01

    A variable climate coupled with intense grazing and farming pressure can have devastating effects on the Sudano-Sahel. Traditionally millet and peanut crops are grown in association with two native shrubs Piliostigma reticulatum, and Guiera senegalensis which are coppiced during the growing season. There exist considerable knowledge gaps regarding the mechanisms by which the woody shrub rhizosphere supports enhanced nutrient and moisture levels for use by crops in the Peanut Basin, Senegal. Previous work in the area established increased moisture content, organic matter, and decreased deep drainage beneath shrub-crop inter crops as compared to crop only plots. In this study we followed crop physiological parameters of leaf water potential, stomatal conductance, and leaf temperature as they relate to water stress and yield. In addition we performed a water balance using soil moisture monitoring equipment, meteorological data, and two hydrologic models (HYDRUS and the Penman-Monteith). We also performed analysis of the 13C isotope discrimination in leaf biomass in surrounding farmers' fields as a proxy for moisture stress in order to increase the reach of the research from field scale to regional scale. Preliminary results from peanut plants point towards a significant reduction in crop water stress within crop-shrub treatments as compared to control crop only plots. Preliminary results from millet plants point to decreased early season soil temperatures underneath the crop-shrub treatments. It is hypothesized a major mechanism for increased soil moisture below shrubs is due to hydraulic redistribution (HR) however, we argue that it may simply be the effect of the shrub rhizosphere, and the mulching and shading effects of the shrub canopy and its fallen biomass as it grows throughout the cropping season. Soil temperature at 10cm depth at Keur Matar Site at the beginning of cropping season,

  20. Promotion and consumption of commercially produced foods among children: situation analysis in an urban setting in Senegal.

    PubMed

    Feeley, Alison B; Ndeye Coly, Aminata; Sy Gueye, Ndeye Yaga; Diop, Elhadji Issakha; Pries, Alissa M; Champeny, Mary; Zehner, Elizabeth R; Huffman, Sandra L

    2016-04-01

    This study assessed the promotion of commercially produced foods and consumption of these products by children less than 24 months of age in Dakar Department, Senegal. Interviews with 293 mothers of children attending child health clinics assessed maternal exposure to promotion and maternal recall of foods consumed by the child on the preceding day. Promotion of breastmilk substitutes and commercially produced complementary foods outside health facilities was common with 41.0% and 37.2% of mothers, respectively, reporting product promotions since the birth of their youngest child. Promotion of commercially produced snack food products was more prevalent, observed by 93.5% of mothers. While all mothers reported having breastfed their child, only 20.8% of mothers breastfed their newborn within the first hour after delivery, and 44.7% fed pre-lacteal feeds in the first 3 days after delivery. Of children 6-23 months of age, 20.2% had consumed a breastmilk substitute; 49.1% ate a commercially produced complementary food, and 58.7% ate a commercially produced snack food product on the previous day. There is a need to stop the promotion of breastmilk substitutes, including infant formula, follow-up formula, and growing-up milks. More stringent regulations and enforcement could help to eliminate such promotion to the public through the media and in stores. Promotion of commercial snack foods is concerning, given the high rates of consumption of such foods by children under the age of 2 years. Efforts are needed to determine how best to reduce such promotion and encourage replacement of these products with more nutritious foods. PMID:27061957

  1. HBV carriage in children born from HIV-seropositive mothers in Senegal: The need of birth-dose HBV vaccination.

    PubMed

    Gueye, Sokhna Bousso; Diop-Ndiaye, Halimatou; Lo, Gora; Mintsa, Sandrine; Guindo, Ibrahima; Dia, Aminata; Sow-Sall, Amina; Gaye-Diallo, Aissatou; Mboup, Souleymane; Touré-Kane, Coumba

    2016-05-01

    Hepatitis B is a major public health problem in Senegal, a country with high prevalence and a transmission occurring mainly during infancy. Only, one 6-8 weeks vaccination campaign was initiated in 2005 and it was part of the expanded program of immunization. The aim of this study was to determine the prevalence of HBsAg in children born from HIV-seropositive mothers by using dried blood specimens. Specimens were collected between July 2007 and November 2012 from children aged 2-48 weeks in Dakar and decentralized sites working on HIV mother-to-child transmission prevention. HBsAg detection was performed using Architect HBsAg Qualitative II kit (Abbott Diagnostics, Ireland) and for all reactive samples confirmation was done using Architect HBsAg Qualitative II Confirmatory kit (Abbott Diagnostics, Ireland). Nine hundred thirty samples were collected throughout the country with 66% out of Dakar, the capital city. The median age was 20 weeks and 88% of children were less than 1 year of age with a sex ratio of 1.27 in favor of boys. HBsAg was detected in 28 cases giving a global prevalence of 3%. According to age, HBsAg prevalences were 5.1% for children less than 6 weeks, 4.1% and 4.6%, respectively, for those aged 12-18 weeks and 18-24 weeks of age. The HIV prevalence was 2.6% with no HIV/HBV co-infection. This study showed a high rate of HBV infection in children under 24 months, highlighting the need to promote birth-dose HBV vaccination as recommended by WHO. PMID:26488892

  2. Assessing the well water pollution problem by nitrates in the small scale farming systems of the Niayes region, Senegal

    NASA Astrophysics Data System (ADS)

    Mamadou, S.; Vanclooster, M.

    2009-04-01

    Human activities exert many pressures on the quality of groundwater, and advanced assessment programmes are needed to design sustainable water management strategies. To contribute to this challenge, we assessed the nitrate pollution problem of groundwater wells in the small scale farming systems of the Niayes region in Senegal and explained this water pollution problem in terms of well characteristics and land use properties. A fast rural appraisal was performed in 2007 to collect basic back ground data of the small scale farming systems and well water was analysed in 131 wells for nitrate content, pH and electrical conductivity. For a subset of wells, soil analyses were made of the well environment for assessing the attenuation properties of the protecting soil. Cluster analysis was used to define a well typology, while principal component and multiple correspondence analysis was used to explain the nitrate pollution in terms of well characteristics and other physico-chemical properties of the wells, and land use. The study confirms that the wells are seriously affected by the nitrate pollution problem. Wells can be classified in three well classes, which are characterized by a geographical gradient. Nitrate pollution increases from north to south, while the salinity affects particularly the wells in the northern area of the region. The nitrate levels exceeding 50 ppm are more common in residential areas than in the horticultural fields. The results further show that, even if direct pollution problem of wells cannot be excluded, pollution from leaching out of the root zone of vegetable crops to the groundwater is likely. This is confirmed by the assessment of the farming activities in this area and this is consistent with the low attenuation properties of the soils characterizing this region. Considering the nitrate pollution threshold, we further distinguish very few non-polluting crops in this region, which calls for an urgent adoption of agriculture management

  3. Exposure of sheep to mosquito bites: possible consequences for the transmission risk of Rift Valley Fever in Senegal.

    PubMed

    Chevalier, V; Mondet, B; Diaite, A; Lancelot, R; Fall, A G; Ponçon, N

    2004-09-01

    Rift Valley Fever (RVF) is a growing health problem in West Africa. In northern Senegal, the candidate vectors of this arbovirosis are Aedes (Aedimorphus) vexans Meigen and Culex (Culex) poicilipes Theobald (Diptera: Culicidae). Domestic ruminants are the reservoirs of the virus. A study was undertaken during the 2002 rainy season to assess spatial and temporal variations in exposure to mosquito bites in sheep herds, and to evaluate the possible consequences on the risk of RVF transmission to sheep. Mosquitoes were collected with sheep-baited traps. The number of Ae. vexans females (the predominant species during the 2002 rainy season) trapped per trap-night was the dependent variable in statistical analyses. The trapping periods were divided into six series of two to five consecutive days, from July to November 2002. Three temporary ponds were selected according to their ecological features: depth, bank slope, size and vegetation cover. Traps were laid on the pond bank and in the nearest available compound, close to the sheep night pen. Data were analysed using mixed-effects Poisson models. The explanatory variables were the trapping period, the pond, and the capture site. The exposure to mosquito bites varied according to the pond type, suggesting that the risk of transmission was spatially heterogeneous. However, there was no obvious trend in transmission risk due to the effect of the distance from the compound to the pond. The period with the highest exposure was in October, i.e. when transhumant herds left the Ferlo to relocate to their dry-season settlement. It is thus hypothesized that transhumance, the seasonal movements of herds, plays a significant role in the dissemination of RVF virus in the region. PMID:15347392

  4. Shark Attacks in Dakar and the Cap Vert Peninsula, Senegal: Low Incidence despite High Occurrence of Potentially Dangerous Species

    PubMed Central

    Trape, Sébastien

    2008-01-01

    Background The International Shark Attack File mentions only four unprovoked shark attacks on the coast of West Africa during the period 1828–2004, an area where high concentrations of sharks and 17 species potentially dangerous to man have been observed. To investigate if the frequency of shark attacks could be really low and not just under-reported and whether there are potentially sharks that might attack in the area, a study was carried out in Dakar and the Cap Vert peninsula, Senegal. Methodology/Principal Findings Personnel of health facilities, administrative services, traditional authorities and groups of fishermen from the region of Dakar were interviewed about the occurrence of shark attacks, and visual censuses were conducted along the coastline to investigate shark communities associated with the coasts of Dakar and the Cap Vert peninsula. Six attacks were documented for the period 1947–2005, including two fatal ones attributed to the tiger shark Galeocerdo cuvieri. All attacks concerned fishermen and only one occurred after 1970. Sharks were observed year round along the coastline in waters 3–15 m depth. Two species potentially dangerous for man, the nurse shark Ginglymostoma cirratum and the blacktip shark Carcharhinus limbatus, represented together 94% of 1,071 sharks enumerated during 1,459 hours of observations. Threatening behaviour from sharks was noted in 12 encounters (1.1%), including 8 encounters with C. limbatus, one with Galeocerdo cuvieri and 3 with unidentified sharks. Conclusions/Significance These findings suggest that the frequency of shark attacks on the coast of West Africa is underestimated. However, they also indicate that the risk is very low despite the abundance of sharks. In Dakar area, most encounters along the coastline with potentially dangerous species do not result in an attack. Compared to other causes of water related deaths, the incidence of shark attack appears negligible, at least one thousand fold lower. PMID

  5. Regular treatments of praziquantel do not impact on the genetic make-up of Schistosoma mansoni in Northern Senegal.

    PubMed

    Huyse, T; Van den Broeck, F; Jombart, T; Webster, B L; Diaw, O; Volckaert, F A M; Balloux, F; Rollinson, D; Polman, K

    2013-08-01

    The Senegal River Basin (SRB) experienced a major epidemic of intestinal schistosomiasis in the early nineties, after the construction of a dam for irrigation purposes. Exceptionally low cure rates following praziquantel (PZQ) treatment at the onset of the epidemic raised concerns about PZQ resistant strains of Schistosoma mansoni, although they could also be attributed to the intense transmission at that time. A field study in the same region more than 15 years later found cure rates for S. mansoni still to be low, whereas Schistosomahaematobium responded well to treatment. We collected S. mansoni miracidia from children at base-line prior to treatment, six months after two PZQ treatments and two years after the start of the study when they had received a total of five PZQ treatments. In total, 434 miracidia from 12 children were successfully genotyped with at least six out of nine DNA microsatellite loci. We found no significant differences in the genetic diversity of, and genetic differentiation between parasite populations before and after repeated treatment, suggesting that PZQ treatment does not have an impact on the neutral evolution of the parasite. This is in stark contrast with a similar study in Tanzania where a significant decrease in genetic diversity was observed in S. mansoni miracidia after a single round of PZQ treatment. We argue that PZQ resistance might play a role in our study area, although rapid re-infection cannot be excluded. It is important to monitor this situation carefully and conduct larger field studies with short-term follow-up after treatment. Since PZQ is the only general schistosomicide available, the possibility of PZQ resistance is of great concern both for disease control and for curative use in clinical practice. PMID:23684792

  6. Exposure to MTV's global HIV prevention campaign in Kathmandu, Nepal; São Paulo, Brazil; and Dakar, Senegal.

    PubMed

    Geary, Cynthia Waszak; Burke, Holly McClain; Castelnau, Laure; Neupane, Shailes; Sall, Yacine Ba; Wong, Emily

    2007-02-01

    In 2002 MTV aired a global media campaign, "Staying Alive," to promote HIV prevention among 16- to 25-year-olds. Skeptics believed that a global MTV campaign would reach only a small group of elite young people. MTV increased access to its campaign, however, by making all materials "rights free" to third-party (non-MTV) broadcasters. Over 789 million households in over 166 countries had access to some or all of the campaign. To understand the level of actual exposure and the types of young people exposed, data were analyzed from population-based household surveys in three diverse urban areas where a campaign evaluation was conducted: Kathmandu, Nepal; São Paulo, Brazil and Dakar, Senegal. Exposure rates ranged from 12% in Kathmandu, 23% in São Paulo, and 82% in Dakar, reaching an estimated 32,000, 400,000, 220,000 16- to 25-year-olds in each city, respectively. A number of personal, social and economic characteristics found to predict campaign exposure were identified in each site; in general, these were related to economic status and use of "new" media technologies. Though this skew toward more exposure by those with greater resources existed, we found that the campaign audience was in no way composed only of "elite" young people. (For example, although more of those exposed to the campaign had used the Internet compared with those not exposed, this was not the majority of those exposed in most countries.) The possibility of reaching millions of young people through global networks with minimal marginal costs after production, creates a new paradigm for reaching an important segment of young people. PMID:17411388

  7. Thermal and photoinduced reduction of ionic Au(III) to elemental Au nanoparticles by dissolved organic matter in water: possible source of naturally occurring Au nanoparticles.

    PubMed

    Yin, Yongguang; Yu, Sujuan; Liu, Jingfu; Jiang, Guibin

    2014-01-01

    Naturally occurring Au nanoparticles (AuNPs) have been widely observed in ore deposits, coal, soil, and environmental water. Identifying the source of these naturally occurring AuNPs could be helpful for not only the discovery of Au deposits through advanced exploration methods, but also the elucidation of the biogeochemical cycle and environmental toxicity of ionic Au and engineered AuNPs. Here, we investigated the effect of natural/simulated sunlight and heating on the reduction of ionic Au by ubiquitous dissolved organic matter (DOM) in river water. The reductive process probed by X-ray photoelectron spectroscopy revealed that phenolic, alcoholic, and aldehyde groups in DOM act as reductive sites. Long-time exposure with thermal and photoirradiation induced the further fusion and growth of AuNPs to branched Au nanostructure as precipitation. The formation processes and kinetics of AuNPs were further investigated using humic acid (HA) as the DOM model, with comprehensive characterizing methods. We have observed that HA can reduce ionic Au(III) complex (as chloride or hydroxyl complex) to elemental Au nanoparticles under sunlight or heating. In this process, nearly all of the Au(III) could be reduced to AuNPs, in which HA serves as not only the reductive agent, but also the coating agent to stabilize and disperse AuNPs. The size and stability of AuNPs were highly dependent on the concentration ratio of Au(III) to HA. These results imply that, besides biological processes, this thermal or photochemical reduction process is another possible source of naturally occurring AuNPs in natural environments, which possibly has critical impacts on the transport and transformation of Au and engineered AuNPs. PMID:24471802

  8. Self-assembly of thiolated cyanine aggregates on Au(111) and Au nanoparticle surfaces

    NASA Astrophysics Data System (ADS)

    Menéndez, Guillermo O.; Cortés, Emiliano; Grumelli, Doris; Méndez de Leo, Lucila P.; Williams, Federico J.; Tognalli, Nicolás G.; Fainstein, Alejandro; Vela, María Elena; Jares-Erijman, Elizabeth A.; Salvarezza, Roberto C.

    2012-01-01

    Heptamethinecyanine J-aggregates display sharp, intense fluorescence emission making them attractive candidates for developing a variety of chem-bio-sensing applications. They have been immobilized on planar thiol-covered Au surfaces and thiol-capped Au nanoparticles by weak molecular interactions. In this work the self-assembly of novel thiolated cyanine (CNN) on Au(111) and citrate-capped AuNPs from solutions containing monomers and J-aggregates has been studied by using STM, XPS, PM-IRRAS, electrochemical techniques and Raman spectroscopy. Data show that CNN species adsorb on the Au surfaces by forming thiolate-Au bonds. We found that the J-aggregates are preferentially adsorbed on the Au(111) surface directly from the solution while adsorbed CNN monomers cannot organize into aggregates on the substrate surface. These results indicate that the CNN-Au interaction is not able to disorganize the large J-aggregates stabilized by π-π stacking to optimize the S-Au binding site but it is strong enough to hinder the π-π stacking when CNNs are chemisorbed as monomers. The optical properties of the J-aggregates remain active after adsorption. The possibility of covalently bonding CNN J-aggregates to Au planar surfaces and Au nanoparticles controlling the J-aggregate/Au distance opens a new path regarding their improved stability and the wide range of biological applications of both CNN and AuNP biocompatible systems.Heptamethinecyanine J-aggregates display sharp, intense fluorescence emission making them attractive candidates for developing a variety of chem-bio-sensing applications. They have been immobilized on planar thiol-covered Au surfaces and thiol-capped Au nanoparticles by weak molecular interactions. In this work the self-assembly of novel thiolated cyanine (CNN) on Au(111) and citrate-capped AuNPs from solutions containing monomers and J-aggregates has been studied by using STM, XPS, PM-IRRAS, electrochemical techniques and Raman spectroscopy. Data show

  9. Photoionization of Au+, Au2+, and Au3+ ions and developments in the synthesis of the metallofullerene Au@C60

    NASA Astrophysics Data System (ADS)

    Kilcoyne, A. L. David; Muller, Alfred; Schippers, Stefan; Hellhund, Jonas; Borovik, Alexander; Mueller, Allison; Gross, Dylan; Johnson, Andrea; Macaluso, David; A. L. D. Kilcoyne Collaboration

    2015-05-01

    Absolute single photoionization of Au+, Au2+, and Au3+ ions was investigated via the merged-beams technique at AMO Beamline 10.0.1.2 of the Advanced Light Source at Lawrence Berkeley National Laboratory. The absolute single photoionization yield was measured as a function of photon energy for each species from the metastable state ionization threshold region to well above the ground state ionization potential. Additional high-resolution measurements were performed for Au+ and Au2+ ions in the region of the ground and metastable state ionization thresholds to better resolve the detailed resonant structure found therein. This structure was used, along with the reported excited state energy levels of Au+, to preliminarily identify previously unreported excitation levels in all three ions. In addition and as a component of the same program, photoionization studies of the endohedral metallofullerene Au@C60+were performed using endohedral fullerene samples synthesized on-site at Beamline 10.0.1.2 of the ALS.

  10. Controlled Synthesis of Au@AgAu Yolk-Shell Cuboctahedra with Well-Defined Facets.

    PubMed

    Londono-Calderon, Alejandra; Bahena, Daniel; Yacaman, Miguel J

    2016-08-01

    The synthesis of Au@AgAu yolk-shell cuboctahedra nanoparticles formed by galvanic replacement in a seed-mediated method is described. Initially, single-crystal Au seeds are used for the formation of Au@Ag core-shell nanocubes, which serve as the template material for the deposition of an external Au layer. The well-controlled synthesis yields the formation of cuboctahedra nanoparticles with smooth inner and outer Au/Ag surfaces. The deposition/oxidation process is described to understand the formation of cuboctahedra and octahedra nanoparticles. The Au core maintains the initial morphology of the seed and remains static at the center of the yolk-shell because of residual Ag. Structural analysis of the shell indicates intrinsic stacking faults (SFs) near the surface. Energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) compositional analysis show an Au-Ag nonordered alloy forming the shell. The three-dimensional structure of the nanoparticles presented open facets on the [111] as observed by electron tomography SIRT reconstruction over a stack of high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) images. The geometrical model was validated by analyzing the direction of streaks in coherent nanobeam diffraction (NBD). The catalytic activity was evaluated using a model reaction based on the reduction of 4-nitrophenol (4-NTP) by NaBH4 in the presence of Au@AgAu yolk-shell nanoparticles. PMID:27385583

  11. First Description of the Extended Spectrum-Beta-Lactamase Gene blaCTX-M-109 in Salmonella Grumpensis Strains Isolated from Neonatal Nosocomial Infections in Dakar, Senegal

    PubMed Central

    Seck, Abdoulaye; Dia, Mouhamadou Lamine; Timbiné, Lassina Gadi; Niang, Aïssatou Ameth; Ndiaye, El Hadji Momar; Sonko, Mouhamadou Abdoulaye; Wane, Abdoul Aziz; Bercion, Raymond; Ndiaye, Ousmane; Cissé, Moussa Fafa; Gassama-Sow, Amy

    2016-01-01

    Nosocomial infections are very common in African hospitals, particularly in neonatal units. These infections are most often caused by bacteria such as Escherichia coli, Klebsiella spp and Staphylococcus spp. Salmonella strains are rarely involved in nosocomial infections. Here, we report the first description of S. Grumpensis in neonatal infections in Senegal. Seventeen Salmonella strains were isolated from hospitalized infants’ stool samples. The following resistance phenotype was described in strains: AMXRTICRCFR FOXRCFXRCTXRCAZRIMPSATMRNARNORRCIPRTMRGMRTERSXTR. All isolates were susceptible to imipenem, 15 out of 17 produced an extended spectrum ß-lactamase (ESBL). blaOXA-1, blaSHV-1, blaTEM-1, blaCTX-M1 genes were detected in strains 8, 13, 5 and 8, respectively. blaCTX-M1 sequencing revealed the presence of blaCTX-M-109. Thirteen of the 17 Salmonella Grumpensis strains were analyzed by PFGE. These 13 isolates belonged to a single pulsotype and were genotypically identical. This is the first report of neonatal S. Grumpensis infections in Senegal, and the first report of blaCTX-M-109 in the genus Salmonella. PMID:27355480

  12. Male clients of brothel prostitutes as a bridge for HIV infection between high risk and low risk groups of women in Senegal

    PubMed Central

    d Gomes; Etheredge, G

    2005-01-01

    Objective: To explore the extent to which male clients of prostitutes have a role as a bridge in the spread of HIV into the general population of Dakar, Senegal. Methods: A sexual behaviour HIV prevalence survey was carried out among clients of female prostitutes working in brothels recruited outside the prostitutes' rooms after the encounter. All men entering the house and leaving the women's rooms were asked to answer the questions and to donate saliva for HIV-1 and HIV-2 testing. Results: Findings suggest that a proportion of clients form a potential bridge for HIV transmission between prostitutes and partners from the general population. They have unprotected sexual contacts with both brothel prostitutes, and steady and casual partners, and expose both unmarried and married women to HIV infection. Findings also indicate that wives are more exposed to HIV than other categories of women in the population. Conclusions: Clients of brothels' prostitutes have a significant potential for spreading HIV beyond the initial high risk behaviour groups in Senegal. Efforts should be provided to target specific groups at higher risk for HIV infection, such as young men from the densely populated working class neighbourhoods of Dakar, and women outside the commercial sex networks for HIV education and prevention. PMID:16061544

  13. First Description of the Extended Spectrum-Beta-Lactamase Gene blaCTX-M-109 in Salmonella Grumpensis Strains Isolated from Neonatal Nosocomial Infections in Dakar, Senegal.

    PubMed

    Diop, Amadou; Sambe-Ba, Bissoume; Seck, Abdoulaye; Dia, Mouhamadou Lamine; Timbiné, Lassina Gadi; Niang, Aïssatou Ameth; Ndiaye, El Hadji Momar; Sonko, Mouhamadou Abdoulaye; Wane, Abdoul Aziz; Bercion, Raymond; Ndiaye, Ousmane; Cissé, Moussa Fafa; Gassama-Sow, Amy

    2016-01-01

    Nosocomial infections are very common in African hospitals, particularly in neonatal units. These infections are most often caused by bacteria such as Escherichia coli, Klebsiella spp and Staphylococcus spp. Salmonella strains are rarely involved in nosocomial infections. Here, we report the first description of S. Grumpensis in neonatal infections in Senegal. Seventeen Salmonella strains were isolated from hospitalized infants' stool samples. The following resistance phenotype was described in strains: AMXRTICRCFR FOXRCFXRCTXRCAZRIMPSATMRNARNORRCIPRTMRGMRTERSXTR. All isolates were susceptible to imipenem, 15 out of 17 produced an extended spectrum ß-lactamase (ESBL). blaOXA-1, blaSHV-1, blaTEM-1, blaCTX-M1 genes were detected in strains 8, 13, 5 and 8, respectively. blaCTX-M1 sequencing revealed the presence of blaCTX-M-109. Thirteen of the 17 Salmonella Grumpensis strains were analyzed by PFGE. These 13 isolates belonged to a single pulsotype and were genotypically identical. This is the first report of neonatal S. Grumpensis infections in Senegal, and the first report of blaCTX-M-109 in the genus Salmonella. PMID:27355480

  14. Au40: A large tetrahedral magic cluster

    NASA Astrophysics Data System (ADS)

    Jiang, De-En; Walter, Michael

    2011-11-01

    40 is a magic number for tetrahedral symmetry predicted in both nuclear physics and the electronic jellium model. We show that Au40 could be such a a magic cluster from density functional theory-based basin hopping for global minimization. The putative global minimum found for Au40 has a twisted pyramid structure, reminiscent of the famous tetrahedral Au20, and a sizable HOMO-LUMO gap of 0.69 eV, indicating its molecular nature. Analysis of the electronic states reveals that the gap is related to shell closings of the metallic electrons in a tetrahedrally distorted effective potential.

  15. Au40: A Large Tetrahedral Magic Cluster

    SciTech Connect

    Jiang, Deen; Walter, Michael

    2011-01-01

    40 is a magic number for tetrahedral symmetry predicted in both nuclear physics and the electronic jellium model. We show that Au{sub 40} could be such a magic cluster from density functional theory-based basin hopping for global minimization. The putative global minimum found for Au{sub 40} has a twisted pyramid structure, reminiscent of the famous tetrahedral Au{sub 20}, and a sizable HOMO-LUMO gap of 0.69 eV, indicating its molecular nature. Analysis of the electronic states reveals that the gap is related to shell closings of the metallic electrons in a tetrahedrally distorted effective potential.

  16. d + Au hadron correlation measurements from PHENIX

    NASA Astrophysics Data System (ADS)

    Sickles, Anne M.

    2015-01-01

    Recent observations of extended pseudorapidity correlations at the LHC in p+p and p+Pb collisions are of great interest. Here we present related results from d+Au collisions at PHENIX. We present the observed v2 and discuss the possible origin in the geometry of the collision region. We also present new measurements of the pseudorapidity dependence of the ridge in d+Au collision. Future plans to clarify the role of geometry in small collision systems using 3 He + Au collisions are discussed.

  17. Au, Ge and AuGe Nanoparticles Fabricated by Laser Ablation

    SciTech Connect

    Musaev, O.R.; Sutter, E.; Wrobel, J.M.; Kruger, M.B.

    2012-02-01

    A eutectic AuGe target immersed in distilled water was ablated by pulsed ultraviolet laser light. The structure of the ablated material was investigated by high-resolution transmission electron microscopy (HRTEM). The images show formation of nanowire structures of AuGe up to 100 nm in length, with widths of 5-10 nm. These nanostructures have Ge content significantly lower than the target material. Electron diffraction demonstrates that they crystallize in the {alpha}-AuGe structure. For comparison, laser ablation of pure Au and pure Ge targets was also performed under the same conditions. HRTEM shows that Ge forms spherical nanoparticles with a characteristic size of {approx}30 nm. Au forms spherical nanoparticles with diameters of {approx}10 nm. Similar to AuGe, it also forms chainlike structures with substantially lower aspect ratio.

  18. Ir-induced activation of Au towards CO adsorption: Ir films deposited on Au{111}

    NASA Astrophysics Data System (ADS)

    Zhang, Tianfu; Driver, Stephen M.; Pratt, Stephanie J.; Jenkins, Stephen J.; King, David A.

    2016-06-01

    We have investigated the interaction of CO with Ir/Au{111} bimetallic surfaces, and the influence of morphology changes as Ir moves sub-surface into the Au bulk, using reflection-absorption infrared spectroscopy (RAIRS). The presence of Ir stabilises CO on exposed regions of the Au surface at temperatures up to around 200 K: we attribute this to low-coordinated Au sites, probably associated with lifting of the clean-surface 'herringbone' reconstruction by Ir deposition. The highest density of active Au sites is obtained after annealing the bimetallic surface to 500-600 K: we attribute this to morphology changes associated with the movement of Ir into bulk Au.

  19. Charged hadron transverse momentum distributions in Au+Au collisions at S=200 GeV

    NASA Astrophysics Data System (ADS)

    Roland, Christof; PHOBOS Collaboration; Back, B. B.; Baker, M. D.; Barton, D. S.; Betts, R. R.; Ballintijn, M.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; García, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Michałowski, J.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steadman, S. G.; Steinberg, P.; Stephans, G. S. F.; Stodulski, M.; Sukhanov, A.; Tang, J.-L.; Teng, R.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wadsworth, B.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.

    2003-03-01

    We present transverse momentum distributions of charged hadrons produced in Au+Au collisions at sqrt(s_NN) = 200 GeV. The evolution of the spectra for transverse momenta p_T from 0.25 to 5GeV/c is studied as a function of collision centrality over a range from 65 to 344 participating nucleons. We find a significant change of the spectral shape between proton-antiproton and peripheral Au+Au collisions. Comparing peripheral to central Au+Au collisions, we find that the yields at the highest p_T exhibit approximate scaling with the number of participating nucleons, rather than scaling with the number of binary collisions.

  20. RHIC Au beam in Run 2014

    SciTech Connect

    Zhang, S. Y.

    2014-09-15

    Au beam at the RHIC ramp in run 2014 is reviewed together with the run 2011 and run 2012. Observed bunch length and longitudinal emittance are compared with the IBS simulations. The IBS growth rate of the longitudinal emittance in run 2014 is similar to run 2011, and both are larger than run 2012. This is explained by the large transverse emittance at high intensity observed in run 2012, but not in run 2014. The big improvement of the AGS ramping in run 2014 might be related to this change. The importance of the injector intensity improvement in run 2014 is emphasized, which gives rise to the initial luminosity improvement of 50% in run 2014, compared with the previous Au-Au run 2011. In addition, a modified IBS model, which is calibrated using the RHIC Au runs from 9.8 GeV/n to 100 GeV/n, is presented and used in the study.

  1. Counterion-Mediated Assembly of Spherical Nucleic Acid-Au Nanoparticle Conjugates (SNA-AuNPs)

    NASA Astrophysics Data System (ADS)

    Kewalramani, Sumit; Moreau, Liane; Guerrero-García, Guillermo; Mirkin, Chad; Olvera de La Cruz, Monica; Bedzyk, Michael; Afosr Muri Team

    2015-03-01

    Controlled crystallization of colloids from solution has been a goal of material scientists for decades. Recently, nucleic acid functionalized spherical Au nanoparticles (SNA-AuNPs) have been programmed to assemble in a wide variety of crystal structures. In this approach, the assembly is driven by Watson-Crick hybridization between DNAs coating the AuNPs. Here, we show that counterions can induce ordered assembly of SNA-AuNPs in bulk solutions, even in the absence of base pairing interactions. The electrostatics-driven assembly of spherical nucleic acid-Au nanoparticle conjugates (SNA-AuNPs) is probed as a function of counterion concentration and counterion valency [ +1 (Na+) or +2 (Ca2+) ] by in situ solution X-ray scattering. Assemblies of AuNPs capped with single-stranded (ss-) or double-stranded (ds-) DNA are examined. SAXS reveals disordered (gas-like) --> face-centered-cubic (FCC) --> glass-like phase transitions with increasing solution ionic strength. These studies demonstrate how non-base-pairing interactions can be tuned to create crystalline assemblies of SNA-AuNPs. The dependence of the inter-SNA-AuNP interactions on counterion valency and stiffness of the DNA corona will be discussed.

  2. Sclerometric study of galvanic AuNi and AuCo coatings

    NASA Astrophysics Data System (ADS)

    Shugurov, A. R.; Panin, A. V.; Shesterikov, E. V.

    2011-03-01

    Mechanisms of wear in galvanic AuNi and AuCo coatings have been studied using the methods of sclerometry and atomic force microscopy. It is demonstrated that the scratch test at a small load can be used for a comparative analysis of the resistance of metal coatings to abrasive wear. It is established that a developed surface relief related to the formation of grain agglomerates provides for a higher wear resistance of AuCo coatings as compared to that of smooth AuNi films, which is explained by dissipation of the elastic energy of the contact interaction of the sclerometric indenter with the sample surface.

  3. DFT study on cysteine adsorption mechanism on Au(111) and Au(110)

    SciTech Connect

    Buimaga-Iarinca, Luiza; Floare, Calin G.; Calborean, Adrian; Turcu, Ioan

    2013-11-13

    Periodic density functional theory calculations were used to investigate relevant aspects of adsorption mechanisms of cysteine dimers in protonated form on Au(111) and Au(110) surfaces. The projected densities of states are explicitly discussed for all main chemical groups of cysteine, i.e. the amino group (NH2), the thiol group (SH) and the carboxylic group (COOH) to identify differences in adsorption mechanism. Special emphasis is put on the analysis of changes in the electronic structure of molecules adsorbed on Au(111) and Au(110) surfaces as well as the accompanying charge transfer mechanisms at molecule-substrate interaction.

  4. Systematic Measurements of Identified Particle Spectra in pp, d+Au and Au+Au Collisions from STAR

    SciTech Connect

    STAR Coll

    2009-04-11

    Identified charged particle spectra of {pi}{sup {+-}}, K{sup {+-}}, p and {bar p} at mid-rapidity (|y| < 0.1) measured by the dE/dx method in the STAR-TPC are reported for pp and d + Au collisions at {radical}s{sub NN} = 200 GeV and for Au + Au collisions at 62.4 GeV, 130 GeV, and 200 GeV. Average transverse momenta, total particle production, particle yield ratios, strangeness and baryon production rates are investigated as a function of the collision system and centrality. The transverse momentum spectra are found to be flatter for heavy particles than for light particles in all collision systems; the effect is more prominent for more central collisions. The extracted average transverse momentum of each particle species follows a trend determined by the total charged particle multiplicity density. The Bjorken energy density estimate is at least several GeV/fm{sub 3} for a formation time less than 1 fm/c. A significantly larger net-baryon density and a stronger increase of the net-baryon density with centrality are found in Au + Au collisions at 62.4 GeV than at the two higher energies. Antibaryon production relative to total particle multiplicity is found to be constant over centrality, but increases with the collision energy. Strangeness production relative to total particle multiplicity is similar at the three measured RHIC energies. Relative strangeness production increases quickly with centrality in peripheral Au + Au collisions, to a value about 50% above the pp value, and remains rather constant in more central collisions. Bulk freeze-out properties are extracted from thermal equilibrium model and hydrodynamics-motivated blast-wave model fits to the data. Resonance decays are found to have little effect on the extracted kinetic freeze-out parameters due to the transverse momentum range of our measurements. The extracted chemical freeze-out temperature is constant, independent of collision system or centrality; its value is close to the predicted phase

  5. Systematic measurements of identified particle spectra in pp, d+Au, and Au+Au collisions at the star detector.

    SciTech Connect

    Abelev, B. I.; Aggarwal, M. M.; Ahammed, Z.; Anderson, B. D.; Arkhipkin, D.; Krueger, K.; Spinka, H. M.; Underwood, D. G.; High Energy Physics; Univ. of Illinois; Panjab Univ.; Variable Energy Cyclotron Centre; Kent State Univ.; Particle Physic Lab.; STAR Collaboration

    2009-01-01

    Identified charged-particle spectra of {pi}{sup {+-}}, K{sup {+-}}, p, and {bar p} at midrapidity (|y|<0.1) measured by the dE/dx method in the STAR (solenoidal tracker at the BNL Relativistic Heavy Ion Collider) time projection chamber are reported for pp and d+Au collisions at {radical}s{sub NN} = 200 GeV and for Au+Au collisions at 62.4, 130, and 200 GeV. Average transverse momenta, total particle production, particle yield ratios, strangeness, and baryon production rates are investigated as a function of the collision system and centrality. The transverse momentum spectra are found to be flatter for heavy particles than for light particles in all collision systems; the effect is more prominent for more central collisions. The extracted average transverse momentum of each particle species follows a trend determined by the total charged-particle multiplicity density. The Bjorken energy density estimate is at least several GeV/fm{sup 3} for a formation time less than 1 fm/c. A significantly larger net-baryon density and a stronger increase of the net-baryon density with centrality are found in Au+Au collisions at 62.4 GeV than at the two higher energies. Antibaryon production relative to total particle multiplicity is found to be constant over centrality, but increases with the collision energy. Strangeness production relative to total particle multiplicity is similar at the three measured RHIC energies. Relative strangeness production increases quickly with centrality in peripheral Au+Au collisions, to a value about 50% above the pp value, and remains rather constant in more central collisions. Bulk freeze-out properties are extracted from thermal equilibrium model and hydrodynamics-motivated blast-wave model fits to the data. Resonance decays are found to have little effect on the extracted kinetic freeze-out parameters because of the transverse momentum range of our measurements. The extracted chemical freeze-out temperature is constant, independent of

  6. Systematic measurements of identified particle spectra in pp, d+Au, and Au+Au collisions at the STAR detector

    NASA Astrophysics Data System (ADS)

    Abelev, B. I.; Aggarwal, M. M.; Ahammed, Z.; Anderson, B. D.; Arkhipkin, D.; Averichev, G. S.; Bai, Y.; Balewski, J.; Barannikova, O.; Barnby, L. S.; Baudot, J.; Baumgart, S.; Beavis, D. R.; Bellwied, R.; Benedosso, F.; Betts, R. R.; Bhardwaj, S.; Bhasin, A.; Bhati, A. K.; Bichsel, H.; Bielcik, J.; Bielcikova, J.; Biritz, B.; Bland, L. C.; Bombara, M.; Bonner, B. E.; Botje, M.; Bouchet, J.; Braidot, E.; Brandin, A. V.; Bruna, E.; Bueltmann, S.; Burton, T. P.; Bystersky, M.; Cai, X. Z.; Caines, H.; Sánchez, M. Calderón De La Barca; Callner, J.; Catu, O.; Cebra, D.; Cendejas, R.; Cervantes, M. C.; Chajecki, Z.; Chaloupka, P.; Chattopadhyay, S.; Chen, H. F.; Chen, J. H.; Chen, J. Y.; Cheng, J.; Cherney, M.; Chikanian, A.; Choi, K. E.; Christie, W.; Chung, S. U.; Clarke, R. F.; Codrington, M. J. M.; Coffin, J. P.; Cormier, T. M.; Cosentino, M. R.; Cramer, J. G.; Crawford, H. J.; Das, D.; Dash, S.; Daugherity, M.; Silva, C. De; Dedovich, T. G.; Dephillips, M.; Derevschikov, A. A.; de Souza, R. Derradi; Didenko, L.; Djawotho, P.; Dogra, S. M.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Du, F.; Dunlop, J. C.; Mazumdar, M. R. Dutta; Edwards, W. R.; Efimov, L. G.; Elhalhuli, E.; Elnimr, M.; Emelianov, V.; Engelage, J.; Eppley, G.; Erazmus, B.; Estienne, M.; Eun, L.; Fachini, P.; Fatemi, R.; Fedorisin, J.; Feng, A.; Filip, P.; Finch, E.; Fine, V.; Fisyak, Y.; Gagliardi, C. A.; Gaillard, L.; Gangadharan, D. R.; Ganti, M. S.; Garcia-Solis, E.; Ghazikhanian, V.; Ghosh, P.; Gorbunov, Y. N.; Gordon, A.; Grebenyuk, O.; Grosnick, D.; Grube, B.; Guertin, S. M.; Guimaraes, K. S. F. F.; Gupta, A.; Gupta, N.; Guryn, W.; Haag, B.; Hallman, T. J.; Hamed, A.; Harris, J. W.; He, W.; Heinz, M.; Heppelmann, S.; Hippolyte, B.; Hirsch, A.; Hjort, E.; Hoffman, A. M.; Hoffmann, G. W.; Hofman, D. J.; Hollis, R. S.; Huang, H. Z.; Humanic, T. J.; Igo, G.; Iordanova, A.; Jacobs, P.; Jacobs, W. W.; Jakl, P.; Jin, F.; Jones, P. G.; Joseph, J.; Judd, E. G.; Kabana, S.; Kajimoto, K.; Kang, K.; Kapitan, J.; Kaplan, M.; Keane, D.; Kechechyan, A.; Kettler, D.; Khodyrev, V. Yu.; Kiryluk, J.; Kisiel, A.; Klein, S. R.; Knospe, A. G.; Kocoloski, A.; Koetke, D. D.; Kopytine, M.; Kotchenda, L.; Kouchpil, V.; Kravtsov, P.; Kravtsov, V. I.; Krueger, K.; Krus, M.; Kuhn, C.; Kumar, L.; Kurnadi, P.; Lamont, M. A. C.; Landgraf, J. M.; Lapointe, S.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, C.-H.; Levine, M. J.; Li, C.; Li, Y.; Lin, G.; Lin, X.; Lindenbaum, S. J.; Lisa, M. A.; Liu, F.; Liu, H.; Liu, J.; Liu, L.; Ljubicic, T.; Llope, W. J.; Longacre, R. S.; Love, W. A.; Lu, Y.; Ludlam, T.; Lynn, D.; Ma, G. L.; Ma, Y. G.; Mahapatra, D. P.; Majka, R.; Mall, O. I.; Mangotra, L. K.; Manweiler, R.; Margetis, S.; Markert, C.; Matis, H. S.; Matulenko, Yu. A.; McShane, T. S.; Meschanin, A.; Millane, J.; Miller, M. L.; Minaev, N. G.; Mioduszewski, S.; Mischke, A.; Mitchell, J.; Mohanty, B.; Molnar, L.; Morozov, D. A.; Munhoz, M. G.; Nandi, B. K.; Nattrass, C.; Nayak, T. K.; Nelson, J. M.; Nepali, C.; Netrakanti, P. K.; Ng, M. J.; Nogach, L. V.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Okada, H.; Okorokov, V.; Olson, D.; Pachr, M.; Page, B. S.; Pal, S. K.; Pandit, Y.; Panebratsev, Y.; Pawlak, T.; Peitzmann, T.; Perevoztchikov, V.; Perkins, C.; Peryt, W.; Phatak, S. C.; Planinic, M.; Pluta, J.; Poljak, N.; Poskanzer, A. M.; Potukuchi, B. V. K. S.; Prindle, D.; Pruneau, C.; Pruthi, N. K.; Putschke, J.; Raniwala, R.; Raniwala, S.; Ray, R. L.; Reed, R.; Ridiger, A.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Rose, A.; Roy, C.; Ruan, L.; Russcher, M. J.; Rykov, V.; Sahoo, R.; Sakrejda, I.; Sakuma, T.; Salur, S.; Sandweiss, J.; Sarsour, M.; Schambach, J.; Scharenberg, R. P.; Schmitz, N.; Seger, J.; Selyuzhenkov, I.; Seyboth, P.; Shabetai, A.; Shahaliev, E.; Shao, M.; Sharma, M.; Shi, S. S.; Shi, X.-H.; Sichtermann, E. P.; Simon, F.; Singaraju, R. N.; Skoby, M. J.; Smirnov, N.; Snellings, R.; Sorensen, P.; Sowinski, J.; Spinka, H. M.; Srivastava, B.; Stadnik, A.; Stanislaus, T. D. S.; Staszak, D.; Strikhanov, M.; Stringfellow, B.; Suaide, A. A. P.; Suarez, M. C.; Subba, N. L.; Sumbera, M.; Sun, X. M.; Sun, Y.; Sun, Z.; Surrow, B.; Symons, T. J. M.; de Toledo, A. Szanto; Takahashi, J.; Tang, A. H.; Tang, Z.; Tarnowsky, T.; Thein, D.; Thomas, J. H.; Tian, J.; Timmins, A. R.; Timoshenko, S.; Tlusty, D.; Tokarev, M.; Tram, V. N.; Trattner, A. L.; Trentalange, S.; Tribble, R. E.; Tsai, O. D.; Ulery, J.; Ullrich, T.; Underwood, D. G.; Buren, G. Van; van Leeuwen, M.; Molen, A. M. Vander; Vanfossen, J. A., Jr.; Varma, R.; Vasconcelos, G. M. S.; Vasilevski, I. M.; Vasiliev, A. N.; Videbaek, F.; Vigdor, S. E.; Viyogi, Y. P.; Vokal, S.; Voloshin, S. A.; Wada, M.; Waggoner, W. T.; Wang, F.; Wang, G.; Wang, J. S.; Wang, Q.; Wang, X.; Wang, X. L.; Wang, Y.; Webb, J. C.; Westfall, G. D.; Whitten, C., Jr.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, Y.; Xu, N.; Xu, Q. H.; Xu, Y.; Xu, Z.; Yepes, P.; Yoo, I.-K.; Yue, Q.; Zawisza, M.; Zbroszczyk, H.; Zhan, W.; Zhang, H.; Zhang, S.; Zhang, W. M.; Zhang, Y.; Zhang, Z. P.; Zhao, Y.; Zhong, C.; Zhou, J.; Zoulkarneev, R.; Zoulkarneeva, Y.; Zuo, J. X.

    2009-03-01

    Identified charged-particle spectra of π±, K±, p, and pmacr at midrapidity (|y|<0.1) measured by the dE/dx method in the STAR (solenoidal tracker at the BNL Relativistic Heavy Ion Collider) time projection chamber are reported for pp and d+Au collisions at sNN=200 GeV and for Au+Au collisions at 62.4, 130, and 200 GeV. Average transverse momenta, total particle production, particle yield ratios, strangeness, and baryon production rates are investigated as a function of the collision system and centrality. The transverse momentum spectra are found to be flatter for heavy particles than for light particles in all collision systems; the effect is more prominent for more central collisions. The extracted average transverse momentum of each particle species follows a trend determined by the total charged-particle multiplicity density. The Bjorken energy density estimate is at least several GeV/fm3 for a formation time less than 1 fm/c. A significantly larger net-baryon density and a stronger increase of the net-baryon density with centrality are found in Au+Au collisions at 62.4 GeV than at the two higher energies. Antibaryon production relative to total particle multiplicity is found to be constant over centrality, but increases with the collision energy. Strangeness production relative to total particle multiplicity is similar at the three measured RHIC energies. Relative strangeness production increases quickly with centrality in peripheral Au+Au collisions, to a value about 50% above the pp value, and remains rather constant in more central collisions. Bulk freeze-out properties are extracted from thermal equilibrium model and hydrodynamics-motivated blast-wave model fits to the data. Resonance decays are found to have little effect on the extracted kinetic freeze-out parameters because of the transverse momentum range of our measurements. The extracted chemical freeze-out temperature is constant, independent of collision system or centrality; its value is close

  7. High frequency of HIV-1 infections with multiple HIV-1 strains in men having sex with men (MSM) in Senegal.

    PubMed

    Leye, Nafissatou; Vidal, Nicole; Ndiaye, Ousseynou; Diop-Ndiaye, Halimatou; Wade, Abdoulaye Sidibé; Mboup, Souleymane; Delaporte, Eric; Toure-Kane, Coumba; Peeters, Martine

    2013-12-01

    Circulating and unique recombinant HIV-1 strains continue to be identified and their number increases over time, suggesting that co-infection with multiple HIV-1 is frequent. In this study we analyzed to what extent dual infections with different HIV-1 variants occur in a population group with high risk behaviour, high HIV-1 prevalence and in an area where multiple HIV-1 subtypes and Circulating Recombinant Forms (CRFs) co-circulate. We studied 69 MSM with our recently developed multi-region hybridization assay (MHA), based on fluorescent probe detection for eight common variants circulating in West and West Central Africa. At least 11 (15.9%) of the 69 patients were simultaneously infected with two different HIV-1 subtypes and/or CRFs. Among the 29 samples identified as subtype C by MHA in gag, 15 (57.7%) reacted with both C1 and C2 probes. Sequence analysis suggests that the majority of the samples reactive with C1 and C2 probes are most likely infected with two different subtype C clades. Single genome amplification and DNA dilutions confirmed dual infection with subtype D and C for MSM1193, triple infection with two different C subtype strains and one CRF02_AG strain in MSM1157 and showed that MSM3017 is at least co-infected with CRF06_cpx and CRF02_AG and another strain that could not be classified. Comparison of all subtype C sequences from the MSM population and from the general population from this and previous studies confirmed the intermixing of HIV-1 variants between low-risk women and high-risk men as shown by the intermixing of subtype C variants from MSM1157 and a female patient (02SN-HALD478). Comparison of dual infection rates between the general population and MSM in Senegal, show also clearly the importance of high HIV prevalence and high risk behavior in dual infections and subsequent intermixing of HIV-1 variants which can lead to emergence and spread of new recombinants (CRFs). PMID:24035811

  8. [A survey of school teachers' knowledge and behaviour about epilepsy, in a developing country such as Senegal].

    PubMed

    Ndour, D; Diop, A G; Ndiaye, M; Niang, C; Sarr, M M; Ndiaye, I P

    2004-03-01

    Epilepsy is one of the most common disorders encountered in children of developing countries. In Senegal, as in many other African countries, the disease is enrobed in superstition, discrimination, and stigma. There is a clear-cut lack of information programs in the developing world about seizures and epilepsy. Academic achievement of children with epilepsy is hampered by social barriers in addition to the burden of the disease and its treatment. The aim of this study was to evaluate teachers'knowledge, awareness, and current attitudes about epilepsy in order to obtain baseline data for the development of a school health education program on epilepsy. The study was carried out in Dakar. It was conducted by sending self-administered and anonymous questionnaires to 400 elementary school teachers; the data were randomly mapped, stratified, and chosen to produce a statistically representative sample of the teacher population of Dakar. The questionnaires contained 22 items related to knowledge of epilepsy, the attitude of teachers towards epilepsy, and their ability to provide first aid in case of seizures. A total of 373 teachers (93p.cent) completed the questionnaires. For 69p.cent, epilepsy arises in the brain, for 28.7p.cent it is a subnatural affliction. Epilepsy was considered to be contagious for 24p.cent and could be cured for 73p.cent. Although 66p.cent would help an epileptic pupil during a seizure, 53p.cent mentioned harmful measures. Eighty-four percent noticed that an epileptic child could go to a normal classroom, while 62.5p.cent would prefer a special school. Eighty-four percent said their knowledge on epilepsy was not sufficient and the majority (99p.cent) desired training on epilepsy. For 25.7p.cent, better collaboration between parents, doctors, and teachers would b helpful to achieve better management of epileptic children. This study demonstrated encouraging knowledge of teachers about epilepsy. However, some of their wrong attitudes may be

  9. Retrieval of optical and physical properties of African dust from multiwavelength Raman lidar measurements during the SHADOW campaign in Senegal

    NASA Astrophysics Data System (ADS)

    Veselovskii, I.; Goloub, P.; Podvin, T.; Bovchaliuk, V.; Derimian, Y.; Augustin, P.; Fourmentin, M.; Tanre, D.; Korenskiy, M.; Whiteman, D. N.; Diallo, A.; Ndiaye, T.; Kolgotin, A.; Dubovik, O.

    2016-06-01

    West Africa and the adjacent oceanic regions are very important locations for studying dust properties and their influence on weather and climate. The SHADOW (study of SaHAran Dust Over West Africa) campaign is performing a multiscale and multilaboratory study of aerosol properties and dynamics using a set of in situ and remote sensing instruments at an observation site located at the IRD (Institute for Research and Development) in Mbour, Senegal (14° N, 17° W). In this paper, we present the results of lidar measurements performed during the first phase of SHADOW (study of SaHAran Dust Over West Africa) which occurred in March-April 2015. The multiwavelength Mie-Raman lidar acquired 3β + 2α + 1δ measurements during this period. This set of measurements has permitted particle-intensive properties, such as extinction and backscattering Ångström exponents (BAE) for 355/532 nm wavelengths' corresponding lidar ratios and depolarization ratio at 532 nm, to be determined. The mean values of dust lidar ratios during the observation period were about 53 sr at both 532 and 355 nm, which agrees with the values observed during the SAMUM-1 and SAMUM-2 campaigns held in Morocco and Cabo Verde in 2006 and 2008. The mean value of the particle depolarization ratio at 532 nm was 30 ± 4.5 %; however, during strong dust episodes this ratio increased to 35 ± 5 %, which is also in agreement with the results of the SAMUM campaigns. The backscattering Ångström exponent during the dust episodes decreased to ˜ -0.7, while the extinction Ångström exponent, though negative, was greater than -0.2. Low values of BAE can likely be explained by an increase in the imaginary part of the dust refractive index at 355 nm compared to 532 nm. The dust extinction and backscattering coefficients at multiple wavelengths were inverted to the particle microphysics using the regularization algorithm and the model of randomly oriented spheroids. The analysis performed has demonstrated that the

  10. Application of isotopic tracers as a tool for understanding hydrodynamic behavior of the highly exploited Diass aquifer system (Senegal)

    NASA Astrophysics Data System (ADS)

    Madioune, Diakher Hélène; Faye, Serigne; Orban, Philippe; Brouyère, Serge; Dassargues, Alain; Mudry, Jacques; Stumpp, Christine; Maloszewski, Piotr

    2014-04-01

    The Diass horst aquifer system located 50 km east of Dakar (Senegal) is exploited in two main aquifers covered by a sandy superficial aquifer: the confined/unconfined Palaeocene karstic limestone and the confined Maastrichtian sandstone aquifer underneath. This system has experienced intensive groundwater abstraction during the last 50 years to supply increasing water demand, agricultural and industrial needs. The high abstraction rate from 1989 to 2009 (about 109,000 m3/d) has caused a continuous groundwater level decline (up to 30 m), a modification of the groundwater flow and salinization in parts of the aquifers. The objective of the study is to improve our understanding of the system functioning with regards to high pumping, identify the geochemical reactions that take place in the system, infer origin and timing of recharge by using mainly stable (δ18O, δ2H, 13C) and radioactive (3H and 14C) isotopes. Water types defined in the Piper diagram vary in order of abundance from Ca-HCO3 (65%), Ca/Na-Cl (20%), Na-HCO3 (3%) and Na-Cl (12%). Values of δ18O and δ2H for the superficial aquifer range between -5.8 and -4.2‰ and between -42 and -31‰, respectively. For the Palaeocene aquifer they range from -5.8 to -5.0‰ and from -38 to -31‰, respectively; values in the Maastrichtian aquifer are between -5.9 and -4.3‰ for δ18O and -38 to -26‰ for δ2H. Plotted against the conventional δ18O vs δ2H diagram, data from the upper aquifer exhibit a dispersed distribution with respect to isotopic fractionation while those of the Palaeocene and Maastrichtian aquifers are aligned parallel and slightly below/or on the Global Meteoric Water Line (GMWL) evidencing ancient waters which had evaporated during infiltration. The low tritium (generally <0.7 TU) and 14C (0.7-57.2 pmc) contents indicate predominance of older water being recharged during the Pleistocene and Holocene periods. However, few boreholes which exhibit high tritium (1.2-4.3 TU) and 14C (65.7-70.8 pmc

  11. Successful mLearning Pilot in Senegal: Delivering Family Planning Refresher Training Using Interactive Voice Response and SMS

    PubMed Central

    Diedhiou, Abdoulaye; Gilroy, Kate E; Cox, Carie Muntifering; Duncan, Luke; Koumtingue, Djimadoum; Pacqué-Margolis, Sara; Fort, Alfredo; Settle, Dykki; Bailey, Rebecca

    2015-01-01

    Background: In-service training of health workers plays a pivotal role in improving service quality. However, it is often expensive and requires providers to leave their posts. We developed and assessed a prototype mLearning system that used interactive voice response (IVR) and text messaging on simple mobile phones to provide in-service training without interrupting health services. IVR allows trainees to respond to audio recordings using their telephone keypad. Methods: In 2013, the CapacityPlus project tested the mobile delivery of an 8-week refresher training course on management of contraceptive side effects and misconceptions to 20 public-sector nurses and midwives working in Mékhé and Tivaouane districts in the Thiès region of Senegal. The course used a spaced-education approach in which questions and detailed explanations are spaced and repeated over time. We assessed the feasibility through the system's administrative data, examined participants' experiences using an endline survey, and employed a pre- and post-test survey to assess changes in provider knowledge. Results: All participants completed the course within 9 weeks. The majority of participant prompts to interact with the mobile course were made outside normal working hours (median time, 5:16 pm); average call duration was about 13 minutes. Participants reported positive experiences: 60% liked the ability to determine the pace of the course and 55% liked the convenience. The largest criticism (35% of participants) was poor network reception, and 30% reported dropped IVR calls. Most (90%) participants thought they learned the same or more compared with a conventional course. Knowledge of contraceptive side effects increased significantly, from an average of 12.6/20 questions correct before training to 16.0/20 after, and remained significantly higher 10 months after the end of training than at baseline, at 14.8/20, without any further reinforcement. Conclusions: The mLearning system proved

  12. A Coastal Niño/Niña Phenomenon Off the Coast of Senegal (West Africa)

    NASA Astrophysics Data System (ADS)

    Oettli, P.; Morioka, Y.; Doi, T.; Yamagata, T.

    2014-12-01

    A recent discovery, the Dakar Niño/Niña, is introduced, involving a local air-sea interaction in the southern region of the Canary Current, an eastern boundary current in the North Atlantic Ocean. In the region (20°-15°W, 9°-15°N) located south of the Cap-Vert peninsula (Senegal, Western Africa), Sea Surface Temperature (SST) undergoes a strong seasonal cycle with a minimum variability during boreal late summer/early fall and with a peak in boreal winter when the surface trade-winds are at their peak strength. The present study identifies that this area is subject to anomalous warming/cooling of the SST in boreal winter, during the period 1982-2011. A close examination of the relationships between the SST and the dynamics of the lower atmosphere reveals the important role played by the surface wind, particularly the meridional component and its angle to the coast. At the interannual time-scale, less (more) intense trade winds in February lead to warmer (cooler) SST in March. The interannual variability in trade winds (speed and direction) also has an influence on the intensity of the coastal upwelling. These results have implications for a potential impact on the fish abundance and also on the local fishery and economy. Similar regional warming phenomena have been described in other oceanic basins, such as in the South Atlantic Ocean (Benguela Niño), the southern Indian Ocean (Ningaloo Niño) and the North Pacific Ocean (California Niño). A comparison between the Dakar Niño and the well documented Ningaloo Niño suggests that an important difference arises to be the distinct feedback mechanisms from the ocean into the atmosphere. The Ningaloo Niño (Niña) has significant impacts on regional precipitation in Australia, through changes in SLP anomalies. While the Dakar Niño (Niña) appears to favor the wind-evaporation-SST (WES) feedback, at a local- to regional-scale. The connection between coastal Niño and ENSO is also analyzed.

  13. MALDI-TOF Identification of the Human Gut Microbiome in People with and without Diarrhea in Senegal

    PubMed Central

    Samb-Ba, Bissoume; Mazenot, Catherine; Gassama-Sow, Amy; Dubourg, Grégory; Richet, Hervé; Hugon, Perrine; Lagier, Jean-Christophe; Raoult, Didier; Fenollar, Florence

    2014-01-01

    Background In Africa, there are several problems with the specific identification of bacteria. Recently, MALDI-TOF mass spectrometry has become a powerful tool for the routine microbial identification in many clinical laboratories. Methodology/Principal Findings This study was conducted using feces from 347 individuals (162 with diarrhea and 185 without diarrhea) sampled in health centers in Dakar, Senegal. Feces were transported from Dakar to Marseille, France, where they were cultured using different culture conditions. The isolated colonies were identified using MALDI-TOF. If a colony was unidentified, 16S rRNA sequencing was performed. Overall, 2,753 isolates were tested, allowing for the identification of 189 bacteria from 5 phyla, including 2 previously unknown species, 11 species not previously reported in the human gut, 10 species not previously reported in humans, and 3 fungi. 2,718 bacterial isolates (98.8%) out of 2,750 yielded an accurate identification using mass spectrometry, as did the 3 Candida albicans isolates. Thirty-two bacterial isolates not identified by MALDI-TOF (1.2%) were identified by sequencing, allowing for the identification of 2 new species. The number of bacterial species per fecal sample was significantly higher among patients without diarrhea (8.6±3) than in those with diarrhea (7.3±3.4; P = 0.0003). A modification of the gut microbiota was observed between the two groups. In individuals with diarrhea, major commensal bacterial species such as E. coli were significantly decreased (85% versus 64%), as were several Enterococcus spp. (E. faecium and E. casseliflavus) and anaerobes, such as Bacteroides spp. (B. uniformis and B. vulgatus) and Clostridium spp. (C. bifermentans, C. orbiscindens, C. perfringens, and C. symbosium). Conversely, several Bacillus spp. (B. licheniformis, B. mojavensis, and B. pumilus) were significantly more frequent among patients with diarrhea. Conclusions/Significance MALDI-TOF is a potentially

  14. 100-MeV proton beam intensity measurement by Au activation analysis using 197Au(p, pn)196Au and 197Au(p, p3n)194Au reactions

    NASA Astrophysics Data System (ADS)

    Mokhtari Oranj, Leila; Jung, Nam-Suk; Oh, Joo-Hee; Lee, Hee-Seock

    2016-05-01

    The proton beam intensity of a 100-MeV proton linac at the Korea Multi-purpose Accelerator Complex (KOMAC) was measured by an Au activation analysis using 197Au(p, pn)196Au and 197Au(p, p3n)194Au reactions to determine the accuracy and precision of beam intensity measurement using Gafchromic film dosimetry method. The target, irradiated by 100-MeV protons, was arranged in a stack consisting of Au, Al foils and Pb plates. The yields of produced radio-nuclei in Au foils were obtained by gamma-ray spectroscopy. The FLUKA code was employed to calculate the energy spectrum of protons onto the front surface of Au foils located at three different depth points of the target and also to investigate the condition of incident beam on the target. A good agreement was found between the beam intensity measurements using the activation analysis method at three different depth points of the target. An excellent agreement was also observed between the beam intensity measurements using the Au activation analysis method and the dosimetry method using Gafchromic film.

  15. Impact of combining intermittent preventive treatment with home management of malaria in children less than 10 years in a rural area of Senegal: a cluster randomized trial

    PubMed Central

    2011-01-01

    Background Current malaria control strategies recommend (i) early case detection using rapid diagnostic tests (RDT) and treatment with artemisinin combination therapy (ACT), (ii) pre-referral rectal artesunate, (iii) intermittent preventive treatment and (iv) impregnated bed nets. However, these individual malaria control interventions provide only partial protection in most epidemiological situations. Therefore, there is a need to investigate the potential benefits of integrating several malaria interventions to reduce malaria prevalence and morbidity. Methods A randomized controlled trial was carried out to assess the impact of combining seasonal intermittent preventive treatment in children (IPTc) with home-based management of malaria (HMM) by community health workers (CHWs) in Senegal. Eight CHWs in eight villages covered by the Bonconto health post, (South Eastern part of Senegal) were trained to diagnose malaria using RDT, provide prompt treatment with artemether-lumefantrine for uncomplicated malaria cases and pre-referral rectal artesunate for complicated malaria occurring in children under 10 years. Four CHWs were randomized to also administer monthly IPTc as single dose of sulphadoxine-pyrimethamine (SP) plus three doses of amodiaquine (AQ) in the malaria transmission season, October and November 2010. Primary end point was incidence of single episode of malaria attacks over 8 weeks of follow up. Secondary end points included prevalence of malaria parasitaemia, and prevalence of anaemia at the end of the transmission season. Primary analysis was by intention to treat. The study protocol was approved by the Senegalese National Ethical Committee (approval 0027/MSP/DS/CNRS, 18/03/2010). Results A total of 1,000 children were enrolled. The incidence of malaria episodes was 7.1/100 child months at risk [95% CI (3.7-13.7)] in communities with IPTc + HMM compared to 35.6/100 child months at risk [95% CI (26.7-47.4)] in communities with only HMM (aOR = 0.20; 95

  16. Monthly day/night changes and seasonal daily rhythms of sexual steroids in Senegal sole (Solea senegalensis) under natural fluctuating or controlled environmental conditions.

    PubMed

    Oliveira, Catarina; Vera, Luísa M; López-Olmeda, José F; Guzmán, José M; Mañanós, Evaristo; Ramos, Jesus; Sánchez-Vázquez, F Javier

    2009-02-01

    In this paper we attempted to investigate the existence of daily fluctuations on plasma sexual steroids (17beta-estradiol, E(2) and testosterone, T) in Senegal sole (Solea senegalensis) females. We described the monthly day/night concentrations and seasonal daily rhythms in animals reared under natural photo- and thermo-period. In addition, the influence of the natural annual fluctuation of the water temperature on the plasma concentration of these steroids was investigated, using one group of Senegal sole under a natural photoperiod, but with an attenuated thermal cycle (around 17-20 degrees C) for one year. Although no significant day/night differences were detected in monthly samplings, the existence of an annual rhythm of E(2) and T (p<0.01) with an acrophase in February was revealed by COSINOR analysis. Maximum values were reached in March for both steroids (6.1+/-1.7 ng mL(-1) at mid-dark, MD and 4.0+/-0.6 ng mL(-1) at mid-light, ML for E2 and 1.4+/-0.4 ng mL(-1) at MD and 0.8+/-0.1 ng mL(-1) at ML for T) in anticipation of the spawning season (May-June). As regards seasonal daily rhythms, the presence of daily oscillations was revealed. At the spring solstice (21st March) a daily rhythm was observed for both steroids (COSINOR, p<0.01), with an acrophase at 20:00 h (E(2)) and at 21:08 h (T). In summer, autumn and winter no daily rhythms were observed due to the low steroid levels at those seasons. When Senegal sole females were submitted to an attenuated annual thermal cycle, the steroid rhythm disappeared (there was no surge in spring, as in the control group) and these fish did not spawn, despite being subjected to natural photoperiod conditions. This result underlined the importance of the natural annual fluctuation of water temperature and photoperiod on the synchronization of the spawning season and on the onset of steroidogenesis. PMID:18835359

  17. Mentoring, Task Sharing, and Community Outreach Through the TutoratPlus Approach: Increasing Use of Long-Acting Reversible Contraceptives in Senegal

    PubMed Central

    Gueye, Babacar; Wesson, Jennifer; Koumtingue, Djimadoum; Stratton, Sara; Viadro, Claire; Talla, Hawa; Dioh, Etienne; Cissé, Carol; Sebikali, Boniface; Mamadou Daff, Bocar

    2016-01-01

    ABSTRACT Background: To broaden access to family planning in rural areas and improve contraceptive prevalence, Senegal, in the context of wide method choice, is promoting implants and the intrauterine device, currently used throughout the country by only 5.6% of women of reproductive age who are in union, primarily urban women. Methods: The TutoratPlus performance improvement approach strengthens family planning clinical skills, particularly for long-acting reversible contraceptives (LARCs), through mentoring, task sharing, and community outreach. Following a 2013 baseline situation analysis, 290 participating facilities in 12 of Senegal's 14 regions developed action plans to address gaps identified in 3 areas: provider performance, equipment, and infrastructure. Between 2013 and 2014, 85 trained mentors coached, demonstrated skills, and observed 857 providers, including nurses, nonclinical family planning counselors, and community health workers (CHWs), in LARC service provision through two 5-day visits per facility at 21-day intervals. We used routine service delivery data and TutoratPlus mentoring data to assess changes in contraceptive use, including LARCs, 6 months before and 6 months after the mentoring intervention among 100 of the facilities with complete data. Results: The baseline assessment of 290 facilities found that fewer than half (47%) had a provider who could offer at least 1 LARC method, and 64% to 69% lacked kits. Post-intervention, all 290 facilities were adequately equipped and clinically able to offer LARCs. Among the 552 clinical providers, the percentage with acceptable LARC performance (at least 80% of observation checklist items correct) doubled from 32% to 67% over the 2 mentoring visits. In the 100 facilities with available comparison data, the number of new LARC users rose from 1,552 to 2,879 in the 6 months pre- and post-intervention—an 86% increase. Conclusion: Success of the TutoratPlus approach in Senegal is likely in part

  18. EVENT STRUCTURE AT RHIC FROM P-P TO AU-AU.

    SciTech Connect

    TRAINOR,T.A.

    2004-03-15

    Several correlation analysis techniques are applied to p-p and Au-Au collisions at RHIC. Strong large-momentum-scale correlations are observed which can be related to local charge and momentum conservation during hadronization and to minijet (minimum-bias parton fragment) correlations.

  19. Using supported Au nanoparticles as starting material for preparing uniform Au/Pd bimetallic catalysts

    SciTech Connect

    Villa, Alberto; Prati, Laura; Su, Dangshen; Wang, Di; Veith, Gabriel M

    2010-01-01

    One of the best methods for producing bulk homogeneous (composition) supported bimetallic AuPd clusters involves the immobilization of a protected Au seed followed by the addition of Pd. This paper investigates the importance of this gold seed in controlling the resulting bimetallic AuPd clusters structures, sizes and catalytic activities by investigating three different gold seeds. Uniform Au-Pd alloy were obtained when a steric/electrostatic protecting group, poly(vinyl alcohol) (PVA), was used to form the gold clusters on activated carbon (AC). In contrast Au/AC precursors prepared using Au nanoparticles with only electrostatic stabilization (tetrakis(hydroxypropyl)phosphonium chloride (THPC)), or no stabilization (magnetron sputtering) produced inhomogeneous alloys and segregation of the gold and palladium. The uniform alloyed catalyst (Pd{at}Au{sub PVA}/AC) is the most active and selective catalyst, while the inhomogenous catalysts are less active and selective. Further study of the PVA protected Au clusters revealed that the amount of PVA used is also critical for the preparation of uniform alloyed catalyst, their stability, and their catalytic activity.

  20. Electrochemical Characterization of Protein Adsorption onto YNGRT-Au and VLGXE-Au Surfaces.

    PubMed

    Trzeciakiewicz, Hanna; Esteves-Villanueva, Jose; Soudy, Rania; Kaur, Kamaljit; Martic-Milne, Sanela

    2015-01-01

    The adsorption of the proteins CD13, mucin and bovine serum albumin on VLGXE-Au and YNGRT-Au interfaces was monitored by electrochemical impedance spectroscopy in the presence of [Fe(CN)6](3-/4-). The hydrophobicity of the Au surface was tailored using specific peptides, blocking agents and diluents. The combination of blocking agents (ethanolamine or n-butylamine) and diluents (hexanethiol or 2-mercaptoethanol) was used to prepare various peptide-modified Au surfaces. Protein adsorption onto the peptide-Au surfaces modified with the combination of n-butylamine and hexanethiol produced a dramatic decrease in the charge transfer resistance, Rct, for all three proteins. In contrast, polar peptide-surfaces induced a minimal change in Rct for all three proteins. Furthermore, an increase in Rct was observed with CD13 (an aminopeptidase overexpressed in certain cancers) in comparison to the other proteins when the VLGXE-Au surface was modified with n-butylamine as a blocking agent. The electrochemical data indicated that protein adsorption may be modulated by tailoring the peptide sequence on Au surfaces and that blocking agents and diluents play a key role in promoting or preventing protein adsorption. The peptide-Au platform may also be used for targeting cancer biomarkers with designer peptides. PMID:26262621

  1. The extraction characteristic of Au-Ag from Au concentrate by thiourea solution

    NASA Astrophysics Data System (ADS)

    Kim, Bongju; Cho, Kanghee; On, Hyunsung; Choi, Nagchoul; Park, Cheonyoung

    2013-04-01

    The cyanidation process has been used commercially for the past 100 years, there are ores that are not amenable to treatment by cyanide. Interest in alternative lixiviants, such as thiourea, halogens, thiosulfate and malononitrile, has been revived as a result of a major increase in gold price, which has stimulated new developments in extraction technology, combined with environmental concern. The Au extraction process using the thiourea solvent has many advantages over the cyanidation process, including higher leaching rates, faster extraction time and less than toxicity. The purpose of this study was investigated to the extraction characteristic of Au-Ag from two different Au concentrate (sulfuric acid washing and roasting) under various experiment conditions (thiourea concentration, pH of solvent, temperature) by thiourea solvent. The result of extraction experiment showed that the Au-Ag extraction was a fast extraction process, reaching equilibrium (maximum extraction rate) within 30 min. The Au-Ag extraction rate was higher in the roasted concentrate than in the sulfuric acid washing. The higher the Au-Ag extraction rate (Au - 70.87%, Ag - 98.12%) from roasted concentrate was found when the more concentration of thiourea increased, pH decreased and extraction temperature increased. This study informs extraction method basic knowledge when thiourea was a possibility to eco-/economic resources of Au-Ag utilization studies including the hydrometallurgy.

  2. Electrochemical Characterization of Protein Adsorption onto YNGRT-Au and VLGXE-Au Surfaces

    PubMed Central

    Trzeciakiewicz, Hanna; Esteves-Villanueva, Jose; Soudy, Rania; Kaur, Kamaljit; Martic-Milne, Sanela

    2015-01-01

    The adsorption of the proteins CD13, mucin and bovine serum albumin on VLGXE-Au and YNGRT-Au interfaces was monitored by electrochemical impedance spectroscopy in the presence of [Fe(CN)6]3−/4−. The hydrophobicity of the Au surface was tailored using specific peptides, blocking agents and diluents. The combination of blocking agents (ethanolamine or n-butylamine) and diluents (hexanethiol or 2-mercaptoethanol) was used to prepare various peptide-modified Au surfaces. Protein adsorption onto the peptide-Au surfaces modified with the combination of n-butylamine and hexanethiol produced a dramatic decrease in the charge transfer resistance, Rct, for all three proteins. In contrast, polar peptide-surfaces induced a minimal change in Rct for all three proteins. Furthermore, an increase in Rct was observed with CD13 (an aminopeptidase overexpressed in certain cancers) in comparison to the other proteins when the VLGXE-Au surface was modified with n-butylamine as a blocking agent. The electrochemical data indicated that protein adsorption may be modulated by tailoring the peptide sequence on Au surfaces and that blocking agents and diluents play a key role in promoting or preventing protein adsorption. The peptide-Au platform may also be used for targeting cancer biomarkers with designer peptides. PMID:26262621

  3. Identified particles in Au+Au collisions at S=200 GeV

    NASA Astrophysics Data System (ADS)

    Phobos Collaboration; Wosiek, Barbara; Back, B. B.; Baker, M. D.; Barton, D. S.; Betts, R. R.; Ballintijn, M.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; García, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Manly, S.; McLeod, D.; Michałowski, J.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steadman, S. G.; Steinberg, P.; Stephans, G. S. F.; Stodulski, M.; Sukhanov, A.; Tang, J.-L.; Teng, R.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wadsworth, B.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.

    2003-03-01

    The yields of identified particles have been measured at RHIC for Au+Au collisions at S=200 GeV using the PHOBOS spectrometer. The ratios of antiparticle to particle yields near mid-rapidity are presented. The first measurements of the invariant yields of charged pions, kaons and protons at very low transverse momenta are also shown.

  4. Observation of anisotropic event shapes and transverse flow in ultrarelativistic Au+Au collisions

    SciTech Connect

    Barrette, J.; Bellwied, R.; Bennett, S.; Braun-Munzinger, P.; Cleland, W.E.; Clemen, M.; Cole, J.; Cormier, T.M.; David, G.; Dee, J.; Dietzsch, O.; Drigert, M.; Gilbert, S.; Hall, J.R.; Hemmick, T.K.; Herrmann, N.; Hong, B.; Jiang, C.L.; Kwon, Y.; Lacasse, R.; Lukaszew, A.; Li, Q.; Ludlam, T.W.; McCorkle, S.; Mark, S.K.; Matheus, R.; O'Brien, E.; Panitkin, S.; Piazza, T.; Pruneau, C.; Rao, M.N.; Rosati, M.; daSilva, N.C.; Sedykh, S.; Sonnadara, U.; Stachel, J.; Takai, H.; Takagui, E.M.; Voloshin, S.; Wang, G.; Wessels, J.P.; Woody, C.L.; Xu, N.; Zhang, Y.; Zhang, Z.; Zou, C. Gesellschaft fuer Schwerionenforschung, Darmstadt Idaho National Engineering Laboratory, Idaho Falls, Idaho 83402 McGill Univesity, Montreal, H3A 2T8 University of Pittsburgh, Pittsburgh, Pennsylvania 15260 SUNY, Stony Brook, New York, 11794 University of Sao Paulo, Sao Paulo

    1994-11-07

    Event shapes for Au + Au collisions at 11.4 GeV/[ital c] per nucleon were studied over nearly the full solid angle with the E877 apparatus. The analysis was performed by Fourier expansion of azimuthal distributions of the transverse energy ([ital E][sub [ital T

  5. The role of plasmons and interband transitions in the color of AuAl2, AuIn2, and AuGa2

    NASA Astrophysics Data System (ADS)

    Keast, V. J.; Birt, K.; Koch, C. T.; Supansomboon, S.; Cortie, M. B.

    2011-09-01

    First principles calculations of the optical properties of the intermetallic compounds AuAl2, AuIn2, and AuGa2 have been performed. Analysis of the dielectric functions showed that AuAl2 is unique because a bulk plasmon is seen in the optical region and contributes to the purple color of this material. An experimental electron energy-loss spectrum showed excellent agreement with the theoretical prediction and confirmed the presence of the bulk plasmon.

  6. Jets and dijets in Au+Au and p+p collisions at RHIC

    SciTech Connect

    Hardtke, D.; STAR Collaboration

    2002-12-09

    Recent data from RHIC suggest novel nuclear effects in the production of high p{sub T} hadrons. We present results from the STAR detector on high p{sub T} angular correlations in Au+Au and p+p collisions at {radical}S = 200 GeV/c. These two-particle angular correlation measurements verify the presence of a partonic hard scattering and fragmentation component at high p{sub T} in both central and peripheral Au+Au collisions. When triggering on a leading hadron with p{sub T}>4 GeV, we observe a quantitative agreement between the jet cone properties in p+p and all centralities of Au+Au collisions. This quantitative agreement indicates that nearly all hadrons with p{sub T}>4 GeV/c come from jet fragmentation and that jet fragmentation properties are not substantially modified in Au+Au collisions. STAR has also measured the strength of back-to-back high p{sub T} charged hadron correlations, and observes a small suppression of the back-to-back correlation strength in peripheral collisions, and a nearly complete disappearance o f back-to-back correlations in central Au+Au events. These phenomena, together with the observed strong suppression of inclusive yields and large value of elliptic flow at high p{sub T}, are consistent with a model where high p{sub T} hadrons come from partons created near the surface of the collision region, and where partons that originate or propagate towards the center of the collision region are substantially slowed or completely absorbed.

  7. Interaction of HNCO with Au(111) surfaces

    NASA Astrophysics Data System (ADS)

    Farkas, A. P.; Berkó, A.; Solymosi, F.

    2012-08-01

    The surface chemistry of isocyanic acid, HNCO, and its dissociation product, NCO, was studied on clean, O-dosed and Ar ion bombarded Au(111) surfaces. The techniques used are high resolution energy loss spectroscopy (HREELS) and temperature-programmed desorption (TPD). The structure of Ar ion etched surface is explored by scanning tunneling microscopy (STM). HNCO adsorbs molecularly on Au(111) surface at 100 K yielding strong losses at 1390, 2270 and 3230 cm- 1. The weakly adsorbed HNCO desorbs in two peaks characterized by Tp = 130 and 145 K. The dissociation of the chemisorbed HNCO occurs at 150 K to give NCO species characterized by a vibration at 2185 cm- 1. The dissociation process is facilitated by the presence of preadsorbed O and by defect sites on Au(111) produced by Ar ion bombardment. In the latter case the loss feature of NCO appeared at 2130 cm- 1. Isocyanate on Au(111) surface was found to be more stable than on the single crystal surfaces of Pt-group metals. Results are compared with those obtained on supported Au catalysts.

  8. Sensitivity analysis of the GEMS soil organic carbon model to land cover land use classification uncertainties under different climate scenarios in Senegal

    USGS Publications Warehouse

    Dieye, A.M.; Roy, D.P.; Hanan, N.P.; Liu, S.; Hansen, M.; Toure, A.

    2011-01-01

    Spatially explicit land cover land use (LCLU) change information is needed to drive biogeochemical models that simulate soil organic carbon (SOC) dynamics. Such information is increasingly being mapped using remotely sensed satellite data with classification schemes and uncertainties constrained by the sensing system, classification algorithms and land cover schemes. In this study, automated LCLU classification of multi-temporal Landsat satellite data were used to assess the sensitivity of SOC modeled by the Global Ensemble Biogeochemical Modeling System (GEMS). The GEMS was run for an area of 1560 km2 in Senegal under three climate change scenarios with LCLU maps generated using different Landsat classification approaches. This research provides a method to estimate the variability of SOC, specifically the SOC uncertainty due to satellite classification errors, which we show is dependent not only on the LCLU classification errors but also on where the LCLU classes occur relative to the other GEMS model inputs. ?? 2011 Author(s).

  9. Modeling nutrients profiles at the sediment-water interface. Calibration and validation from two climatically contrasted estuaries: Seine (France) and Somone (Senegal)

    NASA Astrophysics Data System (ADS)

    Mesnage, Valérie; Lecoq, Nicolas; Sakho, Issa; Vennin, Arnaud

    2013-11-01

    The dialysis porewater sampler, type Hesslein, allows sampling of sediment interstitial water according to a continuous gradient between sediment and the water column. Its equilibration time fluctuates according to the nature of sediment, so it has to be measured in each kind of sediment. The aim of this work is to develop a physical diffusion model in order to determine an equilibration time without using extensive field experiments. The model is validated by real nutrient concentration profiles obtained on two estuaries under different climates, moderate climate (estuary of the Seine) and tropical dry climate (estuary of Somone, Senegal). The results highlight that the equilibration of the dialysis porewater sampler is not homogeneous over the full sediment height investigated. Other sediment characteristics as compaction, rate of bioturbation or bacterial density must be taken into account in order to find a well-calculated value of the equilibration time.

  10. Synthesis and characterization in AuCu–Si nanostructures

    SciTech Connect

    Novelo, T.E.; Amézaga-Madrid, P.; Maldonado, R.D.; Oliva, A.I.; Alonzo-Medina, G.M.

    2015-03-15

    Au/Cu bilayers with different Au:Cu concentrations (25:75, 50:50 and 75:25 at.%) were deposited on Si(100) substrates by thermal evaporation. The thicknesses of all Au/Cu bilayers were 150 nm. The alloys were prepared by thermal diffusion into a vacuum oven with argon atmosphere at 690 K during 1 h. X-ray diffraction analysis revealed different phases of AuCu and CuSi alloys in the samples after annealing process. CuSi alloys were mainly obtained for 25:75 at.% samples, meanwhile the AuCuII phase dominates for samples prepared with 50:50 at.%. Additionally, the Au:Cu alloys with 75:25 at.%, produce Au{sub 2}Cu{sub 3} and Au{sub 3}Cu phases. The formed alloys were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS) to study the morphology and the elemental concentration of the formed alloys. - Highlights: • AuCu/Si alloy thin films were prepared by thermal diffusion. • Alloys prepared with 50 at.% of Au produce the AuCuII phase. • Alloys prepared with 75 at.% of Au produce Au{sub 3}Cu and Au{sub 2}Cu{sub 3} phases. • All alloys present diffusion of Si and Cu through the CuSi alloy formation.

  11. Seasonal and daily plasma melatonin rhythms and reproduction in Senegal sole kept under natural photoperiod and natural or controlled water temperature.

    PubMed

    Vera, L M; De Oliveira, C; López-Olmeda, J F; Ramos, J; Mañanós, E; Madrid, J A; Sánchez-Vázquez, F J

    2007-08-01

    The melatonin daily rhythm provides the organism with photoperiod-related information and represents a mechanism to transduce information concerning time of day. In addition, the duration and amplitude of the nocturnal elevation gives information about duration and thus the time of year. In this study, we investigate the existence of an annual rhythm of plasma melatonin in the Senegal sole. Differences in plasma melatonin levels between fish kept at a controlled temperature (17-20 degrees C) and those exposed to the environmental temperature cycle (11.5-25 degrees C) were also examined throughout the year. Spawning was registered in both groups to determine the time of year in which reproductive rhythms occurred. Our results pointed to the existence of an annual rhythm of plasma melatonin at mid-darkness (MD), with the highest levels (203 +/- 44 pg/mL) observed when water temperature reached 25 degrees C. Water temperature influenced nocturnal, but not diurnal melatonin. Daily melatonin rhythms showed seasonal differences, with higher mean nocturnal levels during the summer solstice (138 +/- 19 pg/mL) and autumn equinox (149 +/- 49 pg/mL). When animals were kept at a constant temperature throughout the year, plasma melatonin levels differed from those observed in fish exposed to the environmental temperature cycle. Regarding the reproductive rhythms, spawning was observed at the end of spring in sole kept under natural temperature conditions, whereas no spawning at all was registered in sole reared at a constant temperature. In short, both photoperiod and temperature affected melatonin production in the Senegal sole, transducing seasonal information and controlling annual reproductive rhythms. PMID:17614835

  12. Ecology of Phlebotomine Sand Flies in the Rural Community of Mont Rolland (Thiès Region, Senegal): Area of Transmission of Canine Leishmaniasis

    PubMed Central

    Senghor, Massila W.; Faye, Malick N.; Faye, Babacar; Diarra, Karamoko; Elguero, Eric; Gaye, Oumar

    2011-01-01

    Background Different epidemiological studies previously indicated that canine leishmaniasis is present in the region of Thiès (Senegal). However, the risks to human health, the transmission cycle and particularly the implicated vectors are unknown. Methodology/Principal Findings To improve our knowledge on the population of phlebotomine sand flies and the potential vectors of canine leishmaniasis, sand flies were collected using sticky traps, light traps and indoor spraying method using pyrethroid insecticides in 16 villages of the rural community of Mont Rolland (Thiès region) between March and July 2005. The 3788 phlebotomine sand flies we collected (2044 males, 1744 females) were distributed among 9 species of which 2 belonged to the genus Phlebotomus: P. duboscqi (vector of cutaneous leishmaniasis in Senegal) and P. rodhaini. The other species belonged to the genus Sergentomyia: S. adleri, S. clydei, S. antennata, S. buxtoni, S. dubia, S. schwetzi and S. magna. The number of individuals and the species composition differed according to the type of trap, suggesting variable, species-related degrees of endophily or exophily. The two species of the genus Phlebotomus were markedly under-represented in comparison to the species of the genus Sergentomyia. This study also shows a heterogeneous spatial distribution within the rural community that could be explained by the different ecosystems and particularly the soil characteristics of this community. Finally, the presence of the S. dubia species appeared to be significantly associated with canine leishmaniasis seroprevalence in dogs. Conclusions/Significance Our data allow us to hypothesize that the species of the genus Sergentomyia and particularly the species S. dubia and S. schwetzi might be capable of transmitting canine leishmaniasis. These results challenge the dogma that leishmaniasis is exclusively transmitted by species of the genus Phlebotomus in the Old World. This hypothesis should be more thoroughly

  13. “Right tool,” wrong “job”: Manual vacuum aspiration, post-abortion care and transnational population politics in Senegal

    PubMed Central

    Suh, Siri

    2015-01-01

    The “rightness” of a technology for completing a particular task is negotiated by medical professionals, patients, state institutions, manufacturing companies, and non-governmental organizations. This paper shows how certain technologies may challenge the meaning of the “job” they are designed to accomplish. Manual vacuum aspiration (MVA) is a syringe device for uterine evacuation that can be used to treat complications of incomplete abortion, known as post-abortion care (PAC), or to terminate pregnancy. I explore how negotiations over the rightness of MVA as well as PAC unfold at the intersection of national and global reproductive politics during the daily treatment of abortion complications at three hospitals in Senegal, where PAC is permitted but induced abortion is legally prohibited. Although state health authorities have championed MVA as the “preferred” PAC technology, the primary donor for PAC, the United States Agency for International Development, does not support the purchase of abortifacient technologies. I conducted an ethnography of Senegal's PAC program between 2010 and 2011. Data collection methods included interviews with 49 health professionals, observation of PAC treatment and review of abortion records at three hospitals, and a review of transnational literature on MVA and PAC. While MVA was the most frequently employed form of uterine evacuation in hospitals, concerns about off-label MVA practices contributed to the persistence of less effective methods such as dilation and curettage (D&C) and digital curettage. Anxieties about MVA's capacity to induce abortion have constrained its integration into routine obstetric care. This capacity also raises questions about what the “job,” PAC, represents in Senegalese hospitals. The prioritization of MVA's security over women's access to the preferred technology reinforces gendered inequalities in health care. PMID:25948127

  14. Quali-quantitative analysis of best selling drugs from pharmacy, street market and traditional herbal medicine: a pilot study of market surveillance in Senegal.

    PubMed

    Pichini, Simona; Rotolo, Maria Concetta; Bellotti, Pasquale; Minutillo, Adele; Mastrobattista, Luisa; Pacifici, Roberta

    2015-02-01

    A pilot study of market surveillance in Senegal has been performed analyzing best selling drugs from an official pharmacy and a street market in two principal cities of Senegal and some traditional preparations from herbal medicine from the same market. A simple and rapid gas chromatography method with mass spectrometry detection has been applied after a liquid-liquid extraction of pharmaceutical products and traditional preparations at acidic, neutral and basic pH with chloroform-isopropanol (9:1, v/v). The assay was validated in the range from 10mg to 250 mg/g powder preparations with good determination coefficients (r(2)≥ 0.99) for the calibration curves. At three concentrations spanning the linear dynamic ranges of the calibration curves, mean recoveries of substances under investigation were always higher than 90% and intra-assay and inter-assay precision and accuracy were always better than 15%. The four best selling drugs purchased from a Dakar local pharmacy exactly contained the amount of active principles reported in the respective labels while the best selling drugs freely purchased from Kaolack market contained an amount of active ingredients lower than that declared on the label. No pharmacological active compound, but salicylic acid was found in one of the traditional herbal preparations. This pilot study showed that whereas official drugs sold in pharmacies at prices accessible for a very few portion of the population contained the amount of active principles as reported in the labels, those from street market bought by the majority of population contained an amount of active ingredients lower than that declared on the label and finally traditional herbal preparations seldom contain pharmacological active principles. PMID:25481086

  15. Weather regimes over Senegal during the summer monsoon season using self-organizing maps and hierarchical ascendant classification. Part I: synoptic time scale

    NASA Astrophysics Data System (ADS)

    Guèye, A. K.; Janicot, Serge; Niang, A.; Sawadogo, S.; Sultan, Benjamin; Diongue-Niang, A.; Thiria, S.

    2011-01-01

    The aim of this work is to define over the period 1979-2002 the main synoptic weather regimes relevant for understanding the daily variability of rainfall during the summer monsoon season over Senegal. "Pure" synoptic weather regimes are defined by removing the influence of seasonal and interannual time scales, in order to highlight the day by day variability of the atmospheric circulation. The Self-Organizing Maps (SOM) approach, a clustering methodology based on non-linear artificial neural network, is combined with a Hierarchical Ascendant Classification to compute these regimes. Nine weather regimes are identified using the mean sea level pressure and 850 hPa wind field as variables, and gathered into three classes. Two of these weather regimes represent the classical 3-5-day African easterly waves with a mean wavelength of about 3,000 km. Three others are characterized by a modulation of the semi-permanent trough located along the western coast of West Africa and might be interpreted in terms of the 6-9-day easterly waves. The last four weather regimes are characterized by a more or less strong north-south dipole of circulation. They can be interpreted as a northward/southward displacement of the Saharan Heat Low for two of them, and a filling/deepening of this depression for the other two. The circulation patterns of all these nine weather regimes are very consistent with the associated anomaly patterns of precipitable water, mid-troposphere vertical velocity, outgoing longwave radiation, and finally rainfall. Rainfall distribution is also highlighted over the southwestern area of Senegal.

  16. Polymorphism in dhfr/dhps genes, parasite density and ex vivo response to pyrimethamine in Plasmodium falciparum malaria parasites in Thies, Senegal.

    PubMed

    Ndiaye, Daouda; Dieye, Baba; Ndiaye, Yaye D; Van Tyne, Daria; Daniels, Rachel; Bei, Amy K; Mbaye, Aminata; Valim, Clarissa; Lukens, Amanda; Mboup, Souleymane; Ndir, Omar; Wirth, Dyann F; Volkman, Sarah

    2013-12-01

    Resistance to sulfadoxine-pyrimethamine (SP) in Plasmodium falciparum malaria parasites is associated with mutations in the dihydrofolate reductase (dhfr) and dihydropteroate synthase (dhps) genes, and these mutations have spread resistance worldwide. SP, used for several years in Senegal, has been recommended for intermittent preventive treatment for malaria in pregnancy (IPTp) and has been widely implemented since 2003 in this country. There is currently limited data on SP resistance from molecular marker genotyping, and no data on pyrimethamine ex vivo sensitivity in Senegal. Molecular markers of SP resistance and pyrimethamine ex vivo sensitivity were investigated in 416 parasite samples collected from the general population, from the Thies region between 2003 and 2011. The prevalence of the N51I/C59R/S108N triple mutation in dhfr increased from 40% in 2003 to 93% in 2011. Furthermore, the prevalence of the dhfr N51I/C59R/S108N and dhps A437G quadruple mutation increased, from 20% to 66% over the same time frame, then down to 44% by 2011. There was a significant increase in the prevalence of the dhfr triple mutation, as well as an association between dhfr genotypes and pyrimethamine response. Conversely, dhps mutations in codons 436 and 437 did not show consistent variation between 2003 and 2011. These findings suggest that regular screening for molecular markers of antifolate resistance and ex vivo drug response monitoring should be incorporated with ongoing in vivo efficacy monitoring in areas where IPTp-SP is implemented and where pyrimethamine and sulfa drugs are still widely administered in the general population. PMID:24533303

  17. Implementation of 5S management method for lean healthcare at a health center in Senegal: a qualitative study of staff perception

    PubMed Central

    Kanamori, Shogo; Sow, Seydou; Castro, Marcia C.; Matsuno, Rui; Tsuru, Akiko; Jimba, Masamine

    2015-01-01

    Background 5S is a lean method for workplace organization; it is an abbreviation representing five Japanese words that can be translated as sort, set in order, shine, standardize, and sustain. The 5S management method has been recognized recently as a potential solution for improving the quality of government healthcare services in low- and middle-income countries. Objective To assess how the 5S management method creates changes in the workplace and in the process and outcomes of healthcare services, and how it can be applicable in a resource-poor setting, based on data from a pilot intervention of the 5S program implemented in a health facility in Senegal. Design In this qualitative study, we interviewed 21 health center staff members 1 year after the pilot intervention. We asked them about their views on the changes brought on by the 5S program in their workplace, daily routines, and services provided. We then transcribed interview records and organized the narrative information by emerging themes using thematic analysis in the coding process. Results Study participants indicated that, despite resource constraints and other demotivating factors present at the health center, the 5S program created changes in the work environment, including fewer unwanted items, improved orderliness, and improved labeling and directional indicators of service units. These efforts engendered changes in the quality of services (e.g. making services more efficient, patient-centered, and safe), and in the attitude and behavior of staff and patients. Conclusions The pilot intervention of the 5S management method was perceived to have improved the quality of healthcare services and staff motivation in a resource-poor healthcare facility with a disorderly work environment in Senegal. Quantitative and qualitative research based on a larger-scale intervention would be needed to elaborate and validate these findings and to identify the cost-effectiveness of such intervention in low- and

  18. [Study of the Consumers' preference on the universal health coverage development strategy through health mutual in Ziguinchor Region, Southwest of Senegal].

    PubMed

    Sagna, O; Seck, I; Dia, A T; Sall, F L; Diouf, S; Mendy, J; Ka, O; Kassoka, B

    2016-08-01

    In Senegal, the informal and rural sector that accounts for over 80% of the population is covered only up to 7% by a health insurance system. That is why, for the implementation of development strategy of the universal health coverage (UHC) through mutual health insurance providers, the Government of Senegal has focused on this sector. The objective of this study was to assess the consumer's preference on the UHC development strategies through mutual health insurance providers. This was a qualitative and exploratory study based on a literature review, and indepth interview with the heads of households. It was also based on focus groups of people with and without health mutual membership, and the Expert Committee meetings. The results showed that the most critical attributes in the decision-making of consumers to join the health mutual in Ziguinchor were the membership units; the content of the benefit package, the payment modalities of the premium, the premium amount, the availability of transportation, the co-payment level, convention arrangement with health facilities, and health mutual governance. For a successful implementation of the UHC development strategy through health mutual organizations, policymakers should explore the possibility of introducing the modality of payment in kind, the revision of the co-payment amount, and the promotion of equity through the introduction of a differentiated premium contribution by income. They should also establish a crossborder strategy with The Gambia and Guinea-Bissau to improve health care access to people living in the borders. The promotion of innovative funding and risk equalization between health insurance schemes is also recommended. In areas where the microfinance institutions are well organized and structured their substitution to health mutuals should be an option the decision-makers have to explore. PMID:27459872

  19. Au nanoparticles films used in biological sensing

    NASA Astrophysics Data System (ADS)

    Rosales Pérez, M.; Delgado Macuil, R.; Rojas López, M.; Gayou, V. L.; Sánchez Ramírez, J. F.

    2009-05-01

    Lactobacillus para paracasei are used commonly as functional food and probiotic substances. In this work Au nanoparticles self-assembled films were used for Lactobacillus para paracasei determination at five different concentrations. Functionalized substrates were immersed in a colloidal solution for one and a half hour at room temperature and dried at room temperature during four hours. After that, drops of Lactobacillus para paracasei in aqueous solution were put into the Au nanoparticles film and let dry at room temperature for another two hours. Infrared spectroscopy in attenuated total reflectance sampling mode was used to observe generation peaks due to substrate silanization, enhancement of Si-O band intensity due to the Au colloids added to silanized substrate and also to observe the enhancement of Lactobacillus para paracasei infrared intensity of the characteristic frequencies at 1650, 1534 and 1450 cm-1 due to surface enhancement infrared absorption.

  20. Au-Ag@Au Hollow Nanostructure with Enhanced Chemical Stability and Improved Photothermal Transduction Efficiency for Cancer Treatment.

    PubMed

    Jiang, Tongtong; Song, Jiangluqi; Zhang, Wenting; Wang, Hao; Li, Xiaodong; Xia, Ruixiang; Zhu, Lixin; Xu, Xiaoliang

    2015-10-01

    Despite the fact that Au-Ag hollow nanoparticles (HNPs) have gained much attention as ablation agents for photothermal therapy, the instability of the Ag element limits their applications. Herein, excess Au atoms were deposited on the surface of a Au-Ag HNP by improving the reduction power of l-ascorbic acid (AA) and thereby preventing the reaction between HAuCl4 and the Ag element in the Au-Ag alloy nanostructure. Significantly, the obtained Au-Ag@Au HNPs show excellent chemical stability in an oxidative environment, together with remarkable increase in extinction peak intensity and obvious narrowing in peak width. Moreover, finite-difference time-domain (FDTD) was used to simulate the optical properties and electric field distribution of HNPs. The calculated results show that the proportion of absorption cross section in total extinction cross section increases with the improvement of Au content in HNP. As predicted by the theoretical calculation results, Au-Ag@Au nanocages (NCs) exhibit a photothermal transduction efficiency (η) as high as 36.5% at 808 nm, which is higher than that of Au-Ag NCs (31.2%). Irradiated by 808 nm laser at power densities of 1 W/cm(2), MCF-7 breast cancer cells incubated with PEGylated Au-Ag@Au NCs were seriously destroyed. Combined together, Au-Ag@Au HNPs with enhanced chemical stability and improved photothermal transduction efficiency show superior competitiveness as photothermal agents. PMID:26371629

  1. Review of the Senegalo-Malian shear zone system - Timing, kinematics and implications for possible Au mineralisation styles

    NASA Astrophysics Data System (ADS)

    Diene, M.; Fullgraf, T.; Diatta, F.; Gloaguen, E.; Gueye, M.; Ndiaye, P. M.

    2015-12-01

    The Kédougou Kénieba Inlier (KKI) of eastern Senegal forms a typical Paleoproterozoic greenstone belt characterised by low-metamorphic sequences of volcanic rocks and volcano-sediments that have been intruded at various stages by gabbroic suites and calc-alkaline granitoids. The main structures of the KKI comprise two anastomosing structures about N-S trending shear belts that are distinguished into the western Main Transcurrent Zone (MTZ) and the eastern Senegalo-Malian shear zone system (SMSZ). These shear belts are taken to define the limits between the western Mako, the central Diale-Kéniebandi and the eastern Daléma-Kofi domains even though transitions exist between their characteristic deposition sequences. Remote sensing analysis of airborne geophysics and satellite data (Landsat, ENVI, SRTM) in combination with geological field mapping, structural analysis and geochronology suggests that the SMSZ represents a Birimian structure that records a main stage of deformation that could characterise the major transcurrent Eburnean tectonics (D2) dated from 2105 Ma (Feybesse et al., 2006a-e). This sinistral transpressive deformation marked by a major constraint oriented NNW-SSE, is accompanied by a NNE-SSW extension leading to the opening of dilational areas such as small pull-apart basins marked by local calk-alkaline volcanic sequences and several coeval intrusions of the Boboti Suite dated 2080 ± 0.9 Ma (Hirdes and Davis, 2002). A post-Birimian to pre-Neoproterozoic deformation post dates the transcurrent phase and is marked by regional N-S extension. Review of the existing Au-mineralisation models in combination with the spatial analysis of soil geochemical data suggest seven possible mineralisation styles that are related to the transpressional tectonics and coeval magmatism.

  2. The role of interfaces in the magnetoresistance of Au/Fe/Au/Fe/GaAs(001)

    SciTech Connect

    Enders, A.; Monchesky, T. L.; Myrtle, K.; Urban, R.; Heinrich, B.; Kirschner, J.; Zhang, X.-G.; Butler, W. H.

    2001-06-01

    The electron transport and magnetoresistance (MR) were investigated in high quality crystalline epitaxial Fe(001) and Au(001) films and exchange coupled Au/Fe/Au/Fe/GaAs(001) trilayer structures. Fits to the experimental data were based on the semiclassical Boltzmann equation, which incorporates the electronic properties obtained from first-principles local density functional calculations. The fits require a surprisingly high asymmetry for the spin dependent electron lifetimes in Fe, {tau}{sup {down_arrow}}/{tau}{sup {up_arrow}}=10 at room temperature. Despite the large atomic terraces at the Au/vacuum and Fe/GaAs interfaces the scattering at the outer interfaces was found to be diffuse. The origin of MR in Au/Fe/Au/Fe/GaAs(001) structures is due to electron channeling in the Au spacer layer. The measured MR is consistent with the diffusivity parameters s{sup {up_arrow}}=0.55, s{sup {down_arrow}}=0.77 at the metal{endash}metal interfaces. {copyright} 2001 American Institute of Physics.

  3. Plasmonic Fano resonance and dip of Au-SiO2-Au nanomatryoshka.

    PubMed

    Liaw, Jiunn-Woei; Chen, Huang-Chih; Kuo, Mao-Kuen

    2013-01-01

    This study theoretically investigates Fano resonances and dips of an Au-SiO2-Au nanomatryoshka that is excited by a nearby electric dipole. An analytical solution of dyadic Green's functions is used to analyze the radiative and nonradiative power spectra of a radial dipole in the proximity of a nanomatryoshka. From these spectra, the plasmon modes and Fano resonances that accompany the Fano dips are identified. In addition, the scattering and absorption spectra of a nanomatryoshka that is illuminated by a plane wave are investigated to confirm these modes and Fano dips. Our results reveal that a Fano dip splits each of the dipole and quadrupole modes into bonding and anti-bonding modes. The Fano dip and resonance result from the destructive interference of the plasmon modes of the Au shell and the Au core. The Fano factors that are obtained from the nonradiative power spectra of the Au shell and the Au core of a nanomatryoshka are in accordance with those obtained from the absorption cross section spectra. Moreover, these Fano factors increase as the plasmonic coupling of the Au shell with the core increases for both dipole and quadrupole modes. PMID:24206789

  4. Plasmonic Fano resonance and dip of Au-SiO2-Au nanomatryoshka

    PubMed Central

    2013-01-01

    This study theoretically investigates Fano resonances and dips of an Au-SiO2-Au nanomatryoshka that is excited by a nearby electric dipole. An analytical solution of dyadic Green's functions is used to analyze the radiative and nonradiative power spectra of a radial dipole in the proximity of a nanomatryoshka. From these spectra, the plasmon modes and Fano resonances that accompany the Fano dips are identified. In addition, the scattering and absorption spectra of a nanomatryoshka that is illuminated by a plane wave are investigated to confirm these modes and Fano dips. Our results reveal that a Fano dip splits each of the dipole and quadrupole modes into bonding and anti-bonding modes. The Fano dip and resonance result from the destructive interference of the plasmon modes of the Au shell and the Au core. The Fano factors that are obtained from the nonradiative power spectra of the Au shell and the Au core of a nanomatryoshka are in accordance with those obtained from the absorption cross section spectra. Moreover, these Fano factors increase as the plasmonic coupling of the Au shell with the core increases for both dipole and quadrupole modes. PMID:24206789

  5. Fabrication of segmented Au/Co/Au nanowires: insights in the quality of Co/Au junctions.

    PubMed

    Jang, Bumjin; Pellicer, Eva; Guerrero, Miguel; Chen, Xiangzhong; Choi, Hongsoo; Nelson, Bradley J; Sort, Jordi; Pané, Salvador

    2014-08-27

    Electrodeposition is a versatile method, which enables the fabrication of a variety of wire-like nanoarchitectures such as nanowires, nanorods, and nanotubes. By means of template-assisted electrodeposition, segmented Au/Co/Au nanowires are grown in anodic aluminum oxide templates from two different electrolytes. To tailor the properties of the cobalt segments, several electrochemical conditions are studied as a function of current density, pulse deposition, and pH. The morphology, crystal structure, and magnetic properties are accordingly investigated. Changes in the deposition conditions affect the cobalt electrocrystallization process directly. Cobalt tends to crystallize mainly in the hexagonal close-packed structure, which is the reason cobalt might not accommodate satisfactorily on the face-centered cubic Au surface or vice versa. We demonstrate that by modifying the electrolyte and the applied current densities, changes in the texture and the crystalline structure of cobalt lead to a good quality connection between dissimilar segments. In particular, lowering the bath pH, or using pulse plating at a high overpotential, produces polycrystalline fcc Co and thus well-connected Co/Au bimetallic junctions with smooth interface. These are crucial factors to be carefully considered taking into account that nanowires are potential building blocks in micro- and nanoelectromechanical systems. PMID:25025496

  6. Evidence of final-state suppression of high-p{_ T} hadrons in Au + Au collisions using d + Au measurements at RHIC

    NASA Astrophysics Data System (ADS)

    Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Becker, B.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Busza, W.; Carroll, A.; Decowski, M. P.; García, E.; Gburek, T.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Harrington, A. S.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Khan, N.; Kulinich, P.; Kuo, C. M.; Lee, J. W.; Lin, W. T.; Manly, S.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Roland, C.; Roland, G.; Sagerer, J.; Sarin, P.; Sedykh, I.; Skulski, W.; Smith, C. E.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Tonjes, M. B.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Veres, G. I.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wysłouch, B.; Zhang, J.

    Transverse momentum spectra of charged hadrons with pT < 6 GeV/c have been measured near mid-rapidity (0.2 < ɛ < 1.4) by the PHOBOS experiment at RHIC in Au + Au and d + Au collisions at {√ {s{NN}} = {200 GeV}}. The spectra for different collision centralities are compared to {p + ¯ {p}} collisions at the same energy. The resulting nuclear modification factor for central Au + Au collisions shows evidence of strong suppression of charged hadrons in the high-pT region (>2 GeV/c). In contrast, the d + Au nuclear modification factor exhibits no suppression of the high-pT yields. These measurements suggest a large energy loss of the high-pT particles in the highly interacting medium created in the central Au + Au collisions. The lack of suppression in d + Au collisions suggests that it is unlikely that initial state effects can explain the suppression in the central Au + Au collisions. PACS: 25.75.-q

  7. Revisiting the S-Au(111) interaction: Static or Dynamic?

    SciTech Connect

    Biener, M M; Biener, J; Friend, C M

    2004-08-17

    The chemical inertness typically observed for Au does not imply a general inability to form stable bonds with non-metals but is rather a consequence of high reaction barriers. The Au-S interaction is probably the most intensively studied interaction of Au surfaces with non-metals as, for example, it plays an important role in Au ore formation, and controls the structure and dynamics of thiol-based self-assembled-monolayers (SAMs). In recent years a quite complex picture of the interaction of sulfur with Au(111) surfaces emerged, and a variety of S-induced surface structures was reported under different conditions. The majority of these structures were interpreted in terms of a static Au surface, where the positions of the Au atoms remain essentially unperturbed. Here we demonstrate that the Au(111) surface exhibits a very dynamic character upon interaction with adsorbed sulfur: low sulfur coverages modify the surface stress of the Au surface leading to lateral expansion of the surface layer; large-scale surface restructuring and incorporation of Au atoms into a growing two-dimensional AuS phase were observed with increasing sulfur coverage. These results provide new insight into the Au-S surface chemistry, and reveal the dynamic character of the Au(111) surface.

  8. Controlled deposition of Au on (BiO)2CO3 microspheres: the size and content of Au nanoparticles matter.

    PubMed

    Li, Qiuyan; Hao, Xiaodong; Guo, Xiaolong; Dong, Fan; Zhang, Yuxin

    2015-05-21

    Novel 3D Au/(BiO)2CO3 (Au/BOC) heterostructures with size-controlled Au nanoparticles (NPs) (2-10 nm) were first synthesized and used in photocatalytic removal of ppb-level NO for air cleaning. The photocatalytic performance of Au/BOC heterostructures was enhanced by fine-tuning the content of Au and the size of Au NPs. A new photocatalysis mechanism of surface scattering and reflecting (SSR) coupled with surface plasmon resonance (SPR) was proposed to understand the enhanced photocatalytic activity. PMID:25906416

  9. Charged hadron transverse momentum distributions in Au+Au collisions at √ SNN = 200 GeV

    NASA Astrophysics Data System (ADS)

    Back, B. B.; Baker, M. D.; Barton, D. S.; Betts, R. R.; Ballintijn, M.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; García, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Michałowski, J.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steadman, S. G.; Steinberg, P.; Stephans, G. S. F.; Stodulski, M.; Sukhanov, A.; Tang, J.-L.; Teng, R.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wadsworth, B.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.; van Nieuwenhuizen, Gerrit; PHOBOS Collaboration

    2003-04-01

    We present transverse momentum distributions of charged hadrons produced in Au+Au collisions at √ SNN = 200 GeV. The evolution of the spectra for transverse momenta p T from 0.25 to 5 GeV/C is studied as a function of collision centrality. We find a significant change of the spectral shape between proton-antiproton and peripheral Au+Au collisions. When comparing peripheral to central Au+Au collisions, we find that the yields at the highest p T exhibit approximate scaling with the number of participating nucleons, rather than scaling with the number of binary collisions.

  10. Suppression of Upsilon production in d + Au and Au + Au collisions at root s(NN) = 200 GeV (vol 735, pg 127, 2014)

    SciTech Connect

    Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Alekseev, I.; Alford, J.; Anson, C. D.; Aparin, A.; Arkhipkin, D.; Gliske, S.; Krueger, K.; Spinka, H. M.; Underwood, D. G.

    2014-07-30

    We report measurements of Υ meson production in p + p, d +Au, and Au+Aucollisions using the STAR detector at RHIC. We compare the Υ yield to the measured cross section in p + p collisions in order to quantify any modifications of the yield in cold nuclear matter using d +Au data and in hot nuclear matter using Au+Au data separated into three centrality classes. Our p +p measurement is based on three times the statistics of our previous result. We obtain a nuclear modification factor for Υ (1S + 2S + 3S) in the rapidity range |y| < 1 in d + Aucollisions of RdAu = 0.79 ± 0.24(stat.) ± 0.03(syst.) ± 0.10(p + p syst.). A comparison with models including shadowing and initial state parton energy loss indicates the presence of additional cold-nuclear matter suppression. Similarly, in the top 10% most-central Au + Au collisions, we measure a nuclear modification factor of R AA = 0.49 ±0.1(stat.) ±0.02(syst.) ±0.06(p + p syst.), which is a larger suppression factor than that seen in cold nuclear matter. Our results are consistent with complete suppression of excited-state Υ mesons in Au + Aucollisions. The additional suppression in Au + Au is consistent with the level expected in model calculations that include the presence of a hot, deconfined Quark–Gluon Plasma. However, understanding the suppression seen in d + Au is still needed before any definitive statements about the nature of the suppression in Au + Au can be made.

  11. Nanoporous Au: an unsupported pure gold catalyst?

    SciTech Connect

    Wittstock, A; Neumann, B; Schaefer, A; Dumbuya, K; Kuebel, C; Biener, M; Zielasek, V; Steinrueck, H; Gottfried, M; Biener, J; Hamza, A; B?umer, M

    2008-09-04

    The unique properties of gold especially in low temperature CO oxidation have been ascribed to a combination of various effects. In particular, particle sizes below a few nm and specific particle-support interactions have been shown to play important roles. On the contrary, recent reports revealed that monolithic nanoporous gold (npAu) prepared by leaching a less noble metal, such as Ag, out of the corresponding alloy can also exhibit remarkably high catalytic activity for CO oxidation, even though no support is present. Therefore, it was claimed to be a pure and unsupported gold catalyst. We investigated npAu with respect to its morphology, surface composition and catalytic properties. In particular, we studied the reaction kinetics for low temperature CO oxidation in detail taking mass transport limitation due to the porous structure of the material into account. Our results reveal that Ag, even if removed almost completely from the bulk, segregates to the surface resulting in surface concentrations of up to 10 at%. Our data suggest that this Ag plays a significant role in activation of molecular oxygen. Therefore, npAu should be considered as a bimetallic catalyst rather than a pure Au catalyst.

  12. Characterization of Au and Bimetallic PtAu Nanoparticles on PDDA-Graphene Sheets as Electrocatalysts for Formic Acid Oxidation

    NASA Astrophysics Data System (ADS)

    Yung, Tung-Yuan; Liu, Ting-Yu; Huang, Li-Ying; Wang, Kuan-Syun; Tzou, Huei-Ming; Chen, Po-Tuan; Chao, Chi-Yang; Liu, Ling-Kang

    2015-09-01

    Nanocomposite materials of the Au nanoparticles (Au/PDDA-G) and the bimetallic PtAu nanoparticles on poly-(diallyldimethylammonium chloride) (PDDA)-modified graphene sheets (PtAu/PDDA-G) were prepared with hydrothermal method at 90 °C for 24 h. The composite materials Au/PDDA-G and PtAu/PDDA-G were evaluated by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA) for exploring the structural characterization for the electrochemical catalysis. According to TEM results, the diameter of Au and bimetallic PtAu nanoparticles is about 20-50 and 5-10 nm, respectively. X-ray diffraction (XRD) results indicate that both of PtAu and Au nanoparticles exhibit the crystalline plane of (111), (200), (210), and (311). Furthermore, XRD data also show the 2°-3° difference between pristine graphene sheets and the PDDA-modified graphene sheets. For the catalytic activity tests of Au/PDDA-G and PtAu/PDDA-G, the mixture of 0.5 M aqueous H2SO4 and 0.5 M aqueous formic acid was used as model to evaluate the electrochemical characterizations. The catalytic activities of the novel bimetallic PtAu/graphene electrocatalyst would be anticipated to be superior to the previous electrocatalyst of the cubic Pt/graphene.

  13. Strangelet search in Au+Au collisions at sNN=200 GeV

    NASA Astrophysics Data System (ADS)

    Abelev, B. I.; Aggarwal, M. M.; Ahammed, Z.; Anderson, B. D.; Arkhipkin, D.; Averichev, G. S.; Bai, Y.; Balewski, J.; Barannikova, O.; Barnby, L. S.; Baudot, J.; Baumgart, S.; Belaga, V. V.; Bellingeri-Laurikainen, A.; Bellwied, R.; Benedosso, F.; Betts, R. R.; Bhardwaj, S.; Bhasin, A.; Bhati, A. K.; Bichsel, H.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Blyth, S.-L.; Bombara, M.; Bonner, B. E.; Botje, M.; Bouchet, J.; Brandin, A. V.; Bravar, A.; Burton, T. P.; Bystersky, M.; Cadman, R. V.; Cai, X. Z.; Caines, H.; Sánchez, M. Calderón De La Barca; Callner, J.; Catu, O.; Cebra, D.; Chajecki, Z.; Chaloupka, P.; Chattopadhyay, S.; Chen, H. F.; Chen, J. H.; Chen, J. Y.; Cheng, J.; Cherney, M.; Chikanian, A.; Christie, W.; Chung, S. U.; Coffin, J. P.; Cormier, T. M.; Cosentino, M. R.; Cramer, J. G.; Crawford, H. J.; Das, D.; Dash, S.; Daugherity, M.; Moura, M. M. De; Dedovich, T. G.; Dephillips, M.; Derevschikov, A. A.; Didenko, L.; Dietel, T.; Djawotho, P.; Dogra, S. M.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Du, F.; Dunin, V. B.; Dunlop, J. C.; Mazumdar, M. R. Dutta; Eckardt, V.; Edwards, W. R.; Efimov, L. G.; Emelianov, V.; Engelage, J.; Eppley, G.; Erazmus, B.; Estienne, M.; Fachini, P.; Fatemi, R.; Fedorisin, J.; Feng, A.; Filip, P.; Finch, E.; Fine, V.; Fisyak, Y.; Fu, J.; Gagliardi, C. A.; Gaillard, L.; Ganti, M. S.; Garcia-Solis, E.; Ghazikhanian, V.; Ghosh, P.; Gorbunov, Y. G.; Gos, H.; Grebenyuk, O.; Grosnick, D.; Guertin, S. M.; Guimaraes, K. S. F. F.; Gupta, N.; Haag, B.; Hallman, T. J.; Hamed, A.; Harris, J. W.; He, W.; Heinz, M.; Henry, T. W.; Hepplemann, S.; Hippolyte, B.; Hirsch, A.; Hjort, E.; Hoffman, A. M.; Hoffmann, G. W.; Hofman, D.; Hollis, R.; Horner, M. J.; Huang, H. Z.; Hughes, E. W.; Humanic, T. J.; Igo, G.; Iordanova, A.; Jacobs, P.; Jacobs, W. W.; Jakl, P.; Jia, F.; Jones, P. G.; Judd, E. G.; Kabana, S.; Kang, K.; Kapitan, J.; Kaplan, M.; Keane, D.; Kechechyan, A.; Kettler, D.; Khodyrev, V. Yu.; Kim, B. C.; Kiryluk, J.; Kisiel, A.; Kislov, E. M.; Klein, S. R.; Knospe, A. G.; Kocoloski, A.; Koetke, D. D.; Kollegger, T.; Kopytine, M.; Kotchenda, L.; Kouchpil, V.; Kowalik, K. L.; Kravtsov, P.; Kravtsov, V. I.; Krueger, K.; Kuhn, C.; Kulikov, A. I.; Kumar, A.; Kurnadi, P.; Kuznetsov, A. A.; Lamont, M. A. C.; Landgraf, J. M.; Lange, S.; Lapointe, S.; Laue, F.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, C.-H.; Lehocka, S.; Levine, M. J.; Li, C.; Li, Q.; Li, Y.; Lin, G.; Lin, X.; Lindenbaum, S. J.; Lisa, M. A.; Liu, F.; Liu, H.; Liu, J.; Liu, L.; Ljubicic, T.; Llope, W. J.; Longacre, R. S.; Love, W. A.; Lu, Y.; Ludlam, T.; Lynn, D.; Ma, G. L.; Ma, J. G.; Ma, Y. G.; Mahapatra, D. P.; Majka, R.; Mangotra, L. K.; Manweiler, R.; Margetis, S.; Markert, C.; Martin, L.; Matis, H. S.; Matulenko, Yu. A.; McClain, C. J.; McShane, T. S.; Melnick, Yu.; Meschanin, A.; Millane, J.; Miller, M. L.; Minaev, N. G.; Mioduszewski, S.; Mironov, C.; Mischke, A.; Mitchell, J.; Mohanty, B.; Morozov, D. A.; Munhoz, M. G.; Nandi, B. K.; Nattrass, C.; Nayak, T. K.; Nelson, J. M.; Nepali, N. S.; Netrakanti, P. K.; Nogach, L. V.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Okorokov, V.; Oldenburg, M.; Olson, D.; Pachr, M.; Pal, S. K.; Panebratsev, Y.; Pavlinov, A. I.; Pawlak, T.; Peitzmann, T.; Perevoztchikov, V.; Perkins, C.; Peryt, W.; Phatak, S. C.; Planinic, M.; Pluta, J.; Poljak, N.; Porile, N.; Poskanzer, A. M.; Potekhin, M.; Potrebenikova, E.; Potukuchi, B. V. K. S.; Prindle, D.; Pruneau, C.; Putschke, J.; Qattan, I. A.; Raniwala, R.; Raniwala, S.; Ray, R. L.; Relyea, D.; Ridiger, A.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Rose, A.; Roy, C.; Ruan, L.; Russcher, M. J.; Sahoo, R.; Sakrejda, I.; Sakuma, T.; Salur, S.; Sandweiss, J.; Sarsour, M.; Sazhin, P. S.; Schambach, J.; Scharenberg, R. P.; Schmitz, N.; Seger, J.; Selyuzhenkov, I.; Seyboth, P.; Shabetai, A.; Shahaliev, E.; Shao, M.; Sharma, M.; Shen, W. Q.; Shimanskiy, S. S.; Sichtermann, E. P.; Simon, F.; Singaraju, R. N.; Smirnov, N.; Snellings, R.; Sorensen, P.; Sowinski, J.; Speltz, J.; Spinka, H. M.; Srivastava, B.; Stadnik, A.; Stanislaus, T. D. S.; Staszak, D.; Stock, R.; Strikhanov, M.; Stringfellow, B.; Suaide, A. A. P.; Suarez, M. C.; Subba, N. L.; Sumbera, M.; Sun, X. M.; Sun, Z.; Surrow, B.; Symons, T. J. M.; Toledo, A. Szanto De; Szeliga, B.; Takahashi, J.; Tang, A. H.; Tarnowsky, T.; Thomas, J. H.; Timmins, A. R.; Timoshenko, S.; Tokarev, M.; Trainor, T. A.; Trentalange, S.; Tribble, R. E.; Tsai, O. D.; Ulery, J.; Ullrich, T.; Underwood, D. G.; Buren, G. Van; Kolk, N. Van Der; Leeuwen, M. Van; Molen, A. M. Vander; Varma, R.; Vasilevski, I. M.; Vasiliev, A. N.; Vernet, R.; Vigdor, S. E.; Viyogi, Y. P.; Vokal, S.; Voloshin, S. A.; Waggoner, W. T.; Wang, F.; Wang, G.; Wang, J. S.; Wang, X. L.; Wang, Y.; Watson, J. W.; Webb, J. C.; Westfall, G. D.; Wetzler, A.; , C. Whitten, Jr.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, J.; Wu, Y.; Xu, N.; Xu, Q. H.; Xu, Z.; Yepes, P.; Yoo, I.-K.; Yue, Q.; Yurevich, V. I.; Zhan, W.; Zhang, H.; Zhang, W. M.; Zhang, Y.; Zhang, Z. P.; Zhao, Y.; Zhong, C.; Zhou, J.; Zoulkarneev, R.; Zoulkarneeva, Y.; Zubarev, A. N.; Zuo, J. X.

    2007-07-01

    We have searched for strangelets in a triggered sample of 61 million central (top 4%) Au+Au collisions at sNN=200 GeV near beam rapidities at the STAR solenoidal tracker detector at the BNL Relativistic Heavy Ion Collider. We have sensitivity to metastable strangelets with lifetimes of order ⩾0.1 ns, in contrast to limits over ten times longer in BNL Alternating Gradient Synchrotron (AGS) studies and longer still at the CERN Super Proton Synchrotron (SPS). Upper limits of a few 10-6 to 10-7 per central Au+Au collision are set for strangelets with mass ≳30 GeV/c2.

  14. Directed Flow of Charged Kaons in Au+Au Collisions from the BES Program at RHIC

    NASA Astrophysics Data System (ADS)

    Pandit, Yadav; STAR Collaboration

    2015-08-01

    We report the measurement of the directed flow (v1) for charged kaons in Au+Au collisions at =7.7, 11.5, 19.6, 27, 39, 62.4 and 200 GeV as a function of rapidity and compare these results for pions, protons and antiprotons. These new kaon results may help to constrain the medium properties and collision dynamics including the in-medium kaon potential and baryon number transport in these collisions.

  15. Flow and bose-einstein correlations in Au-Au collisions at RHIC

    NASA Astrophysics Data System (ADS)

    Phobos Collaboration; Manly, Steven; Back, B. B.; Baker, M. D.; Barton, D. S.; Betts, R. R.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; Garcia, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Henderson, C.; Hofman, D.; Hollis, R. S.; Hołyinski, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Michałowski, J.; Mignerey, A.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steadman, S. G.; Steinberg, P.; Stephans, G. S. F.; Stodulski, M.; Sukhanov, A.; Tang, J.-L.; Teng, R.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wadsworth, B.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.

    2003-03-01

    Argonne flow and Bose-Einstein correlations have been measured in Au-Au collisions at S=130 and 200 GeV using the PHOBOS detector at RHIC. The systematic dependencies of the flow signal on the transverse momentum, pseudorapidity, and centrality of the collision, as well as the beam energy are shown. In addition, results of a 3-dimensional analysis of two-pion correlations in the 200 GeV data are presented.

  16. Photoinduced drug release from thermosensitive AuNPs-liposome using a AuNPs-switch.

    PubMed

    An, Xueqin; Zhang, Fan; Zhu, Yinyan; Shen, Weiguo

    2010-10-14

    A thermosensitive liposome with embedded AuNPs in a bilayer was prepared using supercritical CO(2). The AuNPs-liposome can absorb a certain wavelength light, convert optical energy into heat, induce phase transition, and release drug. The results show that drug release from the liposome is due to the photothermic effects inducing phase transition of the liposome rather than destruction of the liposome structure. PMID:20820547

  17. Enhanced Second Harmonic Generation in AU/AI2O3/AU absorber

    NASA Astrophysics Data System (ADS)

    Huang, Fenglun; Bai, Songang; Li, Qiang; Qu, Yurui; Min, Qiu

    2016-01-01

    A kind of metal-insulator-metal (MIM) metamaterial absorber for generating second harmonic signal is investigated. The absorbers exhibit high absorption efficiency at the dip and notably enhance the generated second harmonic signal by a factor of over 30, in contrast to an Au/alumina double-layer without Au disk on the top. This study demonstrates the potential of metamaterial absorber for nonlinear photonics.

  18. Fabrication of High Sensitive Immunochromato Kit Using Au Colloid

    NASA Astrophysics Data System (ADS)

    Okamoto, Koji

    Au colloid have characteristics of surface plasmon resonance with absorption at 500 nm~600 nm wavelength. Surface on the citric acid Au colloid can be conjugated with protein eg. antibody. Various particle size of Au colloid makes it high sensitive immunochromato as diagnostics. High sensitive immunochromato will be useful for application of cancer marker eg. prostate specific antigen and influenza early diagnosis.

  19. Bonding, Luminescence, Metallophilicity in Linear Au3 and Au2Ag Chains Stabilized by Rigid Diphosphanyl NHC Ligands.

    PubMed

    Ai, Pengfei; Mauro, Matteo; Gourlaouen, Christophe; Carrara, Serena; De Cola, Luisa; Tobon, Yeny; Giovanella, Umberto; Botta, Chiara; Danopoulos, Andreas A; Braunstein, Pierre

    2016-09-01

    The heterofunctional and rigid ligand N,N'-diphosphanyl-imidazol-2-ylidene (PCNHCP; P = P(t-Bu)2), through its phosphorus and two N-heterocyclic carbene (NHC) donors, stabilizes trinuclear chain complexes, with either Au3 or AgAu2 cores, and dinuclear Au2 complexes. The two oppositely situated PCNHCP (L) ligands that "sandwich" the metal chain can support linear and rigid structures, as found in the known tricationic Au(I) complex [Au3(μ3-PCNHCP,κP,κCNHC,κP)2](OTf)3 (OTf = CF3SO3; [Au3L2](OTf)3; Chem. Commun. 2014, 50, 103-105) now also obtained by transmetalation from [Ag3(μ3-PCNHCP,κP,κCNHC,κP)2](OTf)3 ([Ag3L2](OTf)3), or in the mixed-metal tricationic [Au2Ag(μ3-PCNHCP,κP,κCNHC,κP)2](OTf)3 ([Au2AgL2](OTf)3). The latter was obtained stepwise by the addition of AgOTf to the digold(I) complex [Au2(μ2-PCNHCP,κP,κCNHC)2](OTf)2 ([Au2L2](OTf)2). The latter contains two dangling P donors and displays fluxional behavior in solution, and the Au···Au separation of 2.8320(6) Å in the solid state is consistent with metallophilic interactions. In the solvento complex [Au3Cl2(tht)(μ3-PCNHCP,κP,κCNHC,κP)](OTf)·MeCN ([Au3Cl2(tht)L](OTf)·MeCN), which contains only one L and one tht ligand (tht = tetrahydrothiophene), the metal chain is bent (148.94(2)°), and the longer Au···Au separation (2.9710(4) Å) is in line with relaxation of the rigidity due to a more "open" structure. Similar features were observed in [Au3Cl2(SMe2)L](OTf)·2MeCN. A detailed study of the emission properties of [Au3L2](OTf)3, [Au3Cl2(tht)L](OTf)·MeCN, [Au2L2](OTf)2, and [Au2AgL2](OTf)3 was performed by means of steady state and time-resolved photophysical techniques. The complex [Au3L2](OTf)3 displays a bright (photoluminescence quantum yield = 80%) and narrow emission band centered at 446 nm with a relatively small Stokes' shift and long-lived excited-state lifetime on the microsecond timescale, both in solution and in the solid state. In line with the very narrow emission

  20. Experimental and Theoretical Studies on Oxidation of Cu-Au Alloy Surfaces: Effect of Bulk Au Concentration

    PubMed Central

    Okada, Michio; Tsuda, Yasutaka; Oka, Kohei; Kojima, Kazuki; Diño, Wilson Agerico; Yoshigoe, Akitaka; Kasai, Hideaki

    2016-01-01

    We report results of our experimental and theoretical studies on the oxidation of Cu-Au alloy surfaces, viz., Cu3Au(111), CuAu(111), and Au3Cu(111), using hyperthermal O2 molecular beam (HOMB). We observed strong Au segregation to the top layer of the corresponding clean (111) surfaces. This forms a protective layer that hinders further oxidation into the bulk. The higher the concentration of Au in the protective layer formed, the higher the protective efficacy. As a result, of the three Cu-Au surfaces studied, Au3Cu(111) is the most stable against dissociative adsorption of O2, even with HOMB. We also found that this protective property breaks down for oxidations occurring at temperatures above 300 K. PMID:27516137

  1. Identified particle distributions in pp and Au+Au collisions atsqrt sNN=200 GeV

    SciTech Connect

    Adams, J.; Adler, C.; Aggarwal, M.M.; Ahammed, Z.; Amonett, J.; Anderson, B.D.; Anderson, M; Arkhipkin, D.; Averichev, G.S.; Badyal,S.K.; Balewski, J.; Barannikova, O.; Barnby, L.S.; Baudot, J.; Bekele,S.; Belaga, V.V.; Bellwied, R.; Berger, J.; Bezverkhny, B.I.; Bhardwaj,S.; Bhaskar, P.; Bhati, A.K.; Bichsel, H.; Billmeier, A.; Bland, L.C.; Blyth, C.O.; Bonner, B.E.; Botje, M.; Boucham, A.; Brandin, A.; Bravar,A.; Cadman, R.V.; Cai, X.Z.; Caines, H.; Calderon de la Barca Sanchez,M.; Carroll, J.; Castillo, J.; Castro, M.; Cebra, D.; Chaloupka, P.; Chattopadhyay, S.; Chen, H.F.; Chen, Y.; Chernenko, S.P.; Cherney, M.; Chikanian, A.; Choi, B.; Christie, W.; Coffin, J.P.; Cormier, T.M.; Cramer, J.G.; Crawford, H.J.; Das, D.; Das, S.; Derevschikov, A.A.; Didenko, L.; Dietel, T.; Dong, X.; Draper, J.E.; Du, F.; Dubey, A.K.; Dunin, V.B.; Dunlop, J.C.; Dutta Majumdar, M.R.; Eckardt, V.; Efimov,L.G.; Emelianov, V.; Engelage, J.; Eppley, G.; Erazmus, B.; Estienne, M.; Fachini, P.; Faine, V.; Faivre, J.; Fatemi, R.; Filimonov, K.; Filip, P.; Finch, E.; Fisyak, Y.; Flierl, D.; Foley, K.J.; Fu, J.; Gagliardi, C.A.; Ganti, M.S.; Gutierrez, T.D.; Gagunashvili, N.; Gans, J.; Gaudichet, L.; Germain, M.; Geurts, F.; Ghazikhanian, V.; Ghosh, P.; Gonzalez, J.E.; Grachov, O.; Grigoriev, V.; Cronstal, S.; Grosnick, D.; Guedon, M.; Guertin, S.M.; Gupta, A.; Gushin, E.; Hallman, T.J.; Hardtke, D.; Harris,J.W.; Heinz, M.; Henry, T.W.; Heppelmann, S.; Herston, T.; Hippolyte, B.; Hirsch, A.; Hjort, E.; Hoffmann, G.W.; Horsley, M.; Huang, H.Z.; Huang,S.L.; Humanic, T.J.; Igo, G.; Ishihara, A.; Jacobs, P.; Jacobs, W.W.; Janik, M.; Johnson, I.; Jones, P.G.; Judd, E.G.; Kabana, S.; Kaneta, M.; Kaplan, M.; Keane, D.; Kiryluk, J.; Kisiel, A.; Klay, J.; Klein, S.R.; Klyachko, A.; Koetke, D.D.; Kollegger, T.; Konstantinov, A.S.; Kopytine,S.M.; Kotchenda, L.; Kovalenko, A.D.; Kramer, M.; Kravtsov, P.; Krueger,K.; Kuhn, C.; Kulikov, A.I.; Kumar, A.; et al.

    2003-10-06

    Transverse mass and rapidity distributions for charged pions, charged kaons, protons and antiprotons are reported for {radical}sNN = 200 GeV pp and Au+Au collisions at RHIC. The transverse mass distributions are rapidity independent within |y| < 0.5, consistent with a boost-invariant system in this rapidity interval. Spectral shapes and relative particle yields are similar in pp and peripheral Au+Au collisions and change smoothly to central Au+Au collisions. No centrality dependence was observed in the kaon and antiproton production rates relative to the pion production rate from medium-central to central collisions. Chemical and kinetic equilibrium model fits to our data reveal strong radial flow and relatively long duration from chemical to kinetic freeze-out in central Au+Au collisions. The chemical freeze-out temperature appears to be independent of initial conditions at RHIC energies.

  2. Experimental and Theoretical Studies on Oxidation of Cu-Au Alloy Surfaces: Effect of Bulk Au Concentration.

    PubMed

    Okada, Michio; Tsuda, Yasutaka; Oka, Kohei; Kojima, Kazuki; Diño, Wilson Agerico; Yoshigoe, Akitaka; Kasai, Hideaki

    2016-01-01

    We report results of our experimental and theoretical studies on the oxidation of Cu-Au alloy surfaces, viz., Cu3Au(111), CuAu(111), and Au3Cu(111), using hyperthermal O2 molecular beam (HOMB). We observed strong Au segregation to the top layer of the corresponding clean (111) surfaces. This forms a protective layer that hinders further oxidation into the bulk. The higher the concentration of Au in the protective layer formed, the higher the protective efficacy. As a result, of the three Cu-Au surfaces studied, Au3Cu(111) is the most stable against dissociative adsorption of O2, even with HOMB. We also found that this protective property breaks down for oxidations occurring at temperatures above 300 K. PMID:27516137

  3. Charged hadron transverse momentum distributions in Au+Au collisions at √sNN=200 GeV

    NASA Astrophysics Data System (ADS)

    Back, B. B.; Baker, M. D.; Barton, D. S.; Betts, R. R.; Ballintijn, M.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; García, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Lee, J. W.; Manly, S.; McLeod, D.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steadman, S. G.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Tang, J.-L.; Teng, R.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Veres, G. I.; Wadsworth, B.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.

    2004-01-01

    We present transverse momentum distributions of charged hadrons produced in Au+Au collisions at sNN=200 GeV. The spectra were measured for transverse momenta pT from 0.25 to 4.5 GeV/c in a pseudorapidity range of 0.2<η<1.4. The evolution of the spectra is studied as a function of collision centrality, from 65 to 344 participating nucleons. The results are compared to data from proton-antiproton collisions and Au+Au collisions at lower RHIC energies. We find a significant change of the spectral shape between proton-antiproton and semi-peripheral Au+Au collisions. Comparing semi-peripheral to central Au+Au collisions, we find that the yields at high pT exhibit approximate scaling with the number of participating nucleons, rather than scaling with the number of binary collisions.

  4. The effect of Au amount on size uniformity of self-assembled Au nanoparticles

    NASA Astrophysics Data System (ADS)

    Chen, S.-H.; Wang, D.-C.; Chen, G.-Y.; Chen, K.-Y.

    2008-03-01

    The self-assembled fabrication of nanostructure, a dreaming approach in the area of fabrication engineering, is the ultimate goal of this research. A finding was proved through previous research that the size of the self-assembled gold nanoparticles could be controlled with the mole ratio between AuCl4- and thiol. In this study, the moles of Au were fixed, only the moles of thiol were adjusted. Five different mole ratios of Au/S with their effect on size uniformity were investigated. The mole ratios were 1:1/16, 1:1/8, 1:1, 1:8, 1:16, respectively. The size distributions of the gold nanoparticles were analyzed by Mac-View analysis software. HR-TEM was used to derive images of self-assembled gold nanoparticles. The result reached was also the higher the mole ratio between AuCl4- and thiol the bigger the self-assembled gold nanoparticles. Under the condition of moles of Au fixed, the most homogeneous nanoparticles in size distribution derived with the mole ratio of 1:1/8 between AuCl4- and thiol. The obtained nanoparticles could be used, for example, in uniform surface nanofabrication, leading to the fabrication of ordered array of quantum dots.

  5. Azimuthal anisotropy of ϕ meson in U+U and Au+Au collisions at RHIC

    NASA Astrophysics Data System (ADS)

    Bairathi, Vipul

    2016-01-01

    The measurements of the azimuthal anisotropy of φ meson in the U+U and Au+Au collisions at the Relativistic Heavy-Ion Collider (RHIC) are reported. The centrality dependence of the Fourier coefficients v2, v3, v4 and v5 is presented for φ meson at midrapidity (|ƞ| < 1.0), in U+U and Au+Au collisions at -√8NN = 193 and 200 GeV, respectively. The ƞ-sub event plane method is used with a n gap of 0.1 to suppress the non-flow effects. A strong centrality dependence is observed for the φ meson elliptic flow (v2), whereas no clear centrality dependence is observed for v3, v4 and v5. Ratios of the Fourier coefficients, v3/v2 and v4/v22 as a function of transverse momentum (pT) are also presented. A systematic comparison of the Fourier coefficients for the two systems U+U and Au+Au is discussed.

  6. From the Ternary Eu(Au/In)2 and EuAu4(Au/In)2 with Remarkable Au/In Distributions to a New Structure Type: The Gold-Rich Eu5Au16(Au/In)6 Structure.

    PubMed

    Steinberg, Simon; Card, Nathan; Mudring, Anja-Verena

    2015-09-01

    The ternary Eu(Au/In)2 (EuAu(0.46)In(1.54(2))) (I), EuAu4(Au/In)2 (EuAu(4+x)In(2-x) with x = 0.75(2) (II), 0.93(2), and 1.03(2)), and Eu5Au16(Au/In)6 (Eu5Au(17.29)In(4.71(3))) (III) have been synthesized, and their structures were characterized by single-crystal X-ray diffraction. I and II crystallize with the CeCu2-type (Pearson Symbol oI12; Imma; Z = 4; a = 4.9018(4) Å; b = 7.8237(5) Å; c = 8.4457(5) Å) and the YbAl4Mo2-type (tI14; I4/mmm; Z = 2; a = 7.1612(7) Å; c = 5.5268(7) Å) and exhibit significant Au/In disorder. I is composed of an Au/In-mixed diamond-related host lattice encapsulating Eu atoms, while the structure of II features ribbons of distorted, squared Au8 prisms enclosing Eu, Au, and In atoms. Combination of these structural motifs leads to a new structure type as observed for Eu5Au16(Au/In)6 (Eu5Au(17.29)In(4.71(3))) (oS108; Cmcm; Z = 4; a = 7.2283(4) Å; b = 9.0499(6) Å; c = 34.619(2) Å), which formally represents a one-dimensional intergrowth of the series EuAu2-"EuAu4In2". The site preferences of the disordered Au/In positions in II were investigated for different hypothetical "EuAu4(Au/In)2" models using the projector-augmented wave method and indicate that these structures attempt to optimize the frequencies of the heteroatomic Au-In contacts. A chemical bonding analysis on two "EuAu5In" and "EuAu4In2" models employed the TB-LMTO-ASA method and reveals that the subtle interplay between the local atomic environments and the bond energies determines the structural and site preferences for these systems. PMID:26270622

  7. Centrality dependence of direct photon production in (square root)S(NN) = 200 GeV Au + Au collisions.

    PubMed

    Adler, S S; Afanasiev, S; Aidala, C; Ajitanand, N N; Akiba, Y; Alexander, J; Amirikas, R; Aphecetche, L; Aronson, S H; Averbeck, R; Awes, T C; Azmoun, R; Babintsev, V; Baldisseri, A; Barish, K N; Barnes, P D; Bassalleck, B; Bathe, S; Batsouli, S; Baublis, V; Bazilevsky, A; Belikov, S; Berdnikov, Y; Bhagavatula, S; Boissevain, J G; Borel, H; Borenstein, S; Brooks, M L; Brown, D S; Bruner, N; Bucher, D; Buesching, H; Bumazhnov, V; Bunce, G; Burward-Hoy, J M; Butsyk, S; Camard, X; Chai, J-S; Chand, P; Chang, W C; Chernichenko, S; Chi, C Y; Chiba, J; Chiu, M; Choi, I J; Choi, J; Choudhury, R K; Chujo, T; Cianciolo, V; Cobigo, Y; Cole, B A; Constantin, P; d'Enterria, D; David, G; Delagrange, H; Denisov, A; Deshpande, A; Desmond, E J; Devismes, A; Dietzsch, O; Drapier, O; Drees, A; du Rietz, R; Durum, A; Dutta, D; Efremenko, Y V; El Chenawi, K; Enokizono, A; En'yo, H; Esumi, S; Ewell, L; Fields, D E; Fleuret, F; Fokin, S L; Fox, B D; Fraenkel, Z; Frantz, J E; Franz, A; Frawley, A D; Fung, S-Y; Garpman, S; Ghosh, T K; Glenn, A; Gogiberidze, G; Gonin, M; Gosset, J; Goto, Y; Granier de Cassagnac, R; Grau, N; Greene, S V; Perdekamp, M Grosse; Guryn, W; Gustafsson, H-A; Hachiya, T; Haggerty, J S; Hamagaki, H; Hansen, A G; Hartouni, E P; Harvey, M; Hayano, R; Hayashi, N; He, X; Heffner, M; Hemmick, T K; Heuser, J M; Hibino, M; Hill, J C; Holzmann, W; Homma, K; Hong, B; Hoover, A; Ichihara, T; Ikonnikov, V V; Imai, K; Isenhower, D; Ishihara, M; Issah, M; Isupov, A; Jacak, B V; Jang, W Y; Jeong, Y; Jia, J; Jinnouchi, O; Johnson, B M; Johnson, S C; Joo, K S; Jouan, D; Kametani, S; Kamihara, N; Kang, J H; Kapoor, S S; Katou, K; Kelly, S; Khachaturov, B; Khanzadeev, A; Kikuchi, J; Kim, D H; Kim, D J; Kim, D W; Kim, E; Kim, G-B; Kim, H J; Kistenev, E; Kiyomichi, A; Kiyoyama, K; Klein-Boesing, C; Kobayashi, H; Kochenda, L; Kochetkov, V; Koehler, D; Kohama, T; Kopytine, M; Kotchetkov, D; Kozlov, A; Kroon, P J; Kuberg, C H; Kurita, K; Kuroki, Y; Kweon, M J; Kwon, Y; Kyle, G S; Lacey, R; Ladygin, V; Lajoie, J G; Lebedev, A; Leckey, S; Lee, D M; Lee, S; Leitch, M J; Li, X H; Lim, H; Litvinenko, A; Liu, M X; Liu, Y; Maguire, C F; Makdisi, Y I; Malakhov, A; Manko, V I; Mao, Y; Martinez, G; Marx, M D; Masui, H; Matathias, F; Matsumoto, T; McGaughey, P L; Melnikov, E; Messer, F; Miake, Y; Milan, J; Miller, T E; Milov, A; Mioduszewski, S; Mischke, R E; Mishra, G C; Mitchell, J T; Mohanty, A K; Morrison, D P; Moss, J M; Mühlbacher, F; Mukhopadhyay, D; Muniruzzaman, M; Murata, J; Nagamiya, S; Nagle, J L; Nakamura, T; Nandi, B K; Nara, M; Newby, J; Nilsson, P; Nyanin, A S; Nystrand, J; O'Brien, E; Ogilvie, C A; Ohnishi, H; Ojha, I D; Okada, K; Ono, M; Onuchin, V; Oskarsson, A; Otterlund, I; Oyama, K; Ozawa, K; Pal, D; Palounek, A P T; Pantuev, V; Papavassiliou, V; Park, J; Parmar, A; Pate, S F; Peitzmann, T; Peng, J-C; Peresedov, V; Pinkenburg, C; Pisani, R P; Plasil, F; Purschke, M L; Purwar, A K; Rak, J; Ravinovich, I; Read, K F; Reuter, M; Reygers, K; Riabov, V; Riabov, Y; Roche, G; Romana, A; Rosati, M; Rosnet, P; Ryu, S S; Sadler, M E; Saito, N; Sakaguchi, T; Sakai, M; Sakai, S; Samsonov, V; Sanfratello, L; Santo, R; Sato, H D; Sato, S; Sawada, S; Schutz, Y; Semenov, V; Seto, R; Shaw, M R; Shea, T K; Shibata, T-A; Shigaki, K; Shiina, T; Silva, C L; Silvermyr, D; Sim, K S; Singh, C P; Singh, V; Sivertz, M; Soldatov, A; Soltz, R A; Sondheim, W E; Sorensen, S P; Sourikova, I V; Staley, F; Stankus, P W; Stenlund, E; Stepanov, M; Ster, A; Stoll, S P; Sugitate, T; Sullivan, J P; Takagui, E M; Taketani, A; Tamai, M; Tanaka, K H; Tanaka, Y; Tanida, K; Tannenbaum, M J; Tarján, P; Tepe, J D; Thomas, T L; Tojo, J; Torii, H; Towell, R S; Tserruya, I; Tsuruoka, H; Tuli, S K; Tydesjö, H; Tyurin, N; van Hecke, H W; Velkovska, J; Velkovsky, M; Veszprémi, V; Villatte, L; Vinogradov, A A; Volkov, M A; Vznuzdaev, E; Wang, X R; Watanabe, Y; White, S N; Wohn, F K; Woody, C L; Xie, W; Yang, Y; Yanovich, A; Yokkaichi, S; Young, G R; Yushmanov, I E; Zajc, W A; Zhang, C; Zhou, S; Zhou, S J; Zolin, L

    2005-06-17

    The first measurement of direct photons in Au + Au collisions at (square root)S(NN) = 200 GeV is presented. The direct photon signal is extracted as a function of the Au + Au collision centrality and compared to next-to-leading order perturbative quantum chromodynamics calculations. The direct photon yield is shown to scale with the number of nucleon-nucleon collisions for all centralities. PMID:16090462

  8. Spectra and elliptic flow for Λ, Ξ, and Ω in 200 A GeV Au+Au collisions

    NASA Astrophysics Data System (ADS)

    Zhu, Xiangrong; Song, Huichao

    2016-01-01

    Using VISHNU hybrid model, we calculate the pT-spectra and elliptic flow of Λ, Ξ, and Ω in 200 A GeV Au+Au collisions. Comparisons with the STAR measurements show that the model generally describes these soft hadron data. We also briefly study and discuss the mass ordering of elliptic flow among π, K, p, Λ, Ξ, and Ω in minimum bias Au+Au collisions.

  9. AU-FREDI - AUTONOMOUS FREQUENCY DOMAIN IDENTIFICATION

    NASA Technical Reports Server (NTRS)

    Yam, Y.

    1994-01-01

    The Autonomous Frequency Domain Identification program, AU-FREDI, is a system of methods, algorithms and software that was developed for the identification of structural dynamic parameters and system transfer function characterization for control of large space platforms and flexible spacecraft. It was validated in the CALTECH/Jet Propulsion Laboratory's Large Spacecraft Control Laboratory. Due to the unique characteristics of this laboratory environment, and the environment-specific nature of many of the software's routines, AU-FREDI should be considered to be a collection of routines which can be modified and reassembled to suit system identification and control experiments on large flexible structures. The AU-FREDI software was originally designed to command plant excitation and handle subsequent input/output data transfer, and to conduct system identification based on the I/O data. Key features of the AU-FREDI methodology are as follows: 1. AU-FREDI has on-line digital filter design to support on-orbit optimal input design and data composition. 2. Data composition of experimental data in overlapping frequency bands overcomes finite actuator power constraints. 3. Recursive least squares sine-dwell estimation accurately handles digitized sinusoids and low frequency modes. 4. The system also includes automated estimation of model order using a product moment matrix. 5. A sample-data transfer function parametrization supports digital control design. 6. Minimum variance estimation is assured with a curve fitting algorithm with iterative reweighting. 7. Robust root solvers accurately factorize high order polynomials to determine frequency and damping estimates. 8. Output error characterization of model additive uncertainty supports robustness analysis. The research objectives associated with AU-FREDI were particularly useful in focusing the identification methodology for realistic on-orbit testing conditions. Rather than estimating the entire structure, as is

  10. Three views of two giant streams: Aligned observations at 1 AU, 4.6 AU, and 5.9 AU

    NASA Technical Reports Server (NTRS)

    Siscoe, George; Intriligator, Devrie

    1993-01-01

    A close radial alignment of the Interplanetary Monitoring Platform (IMP) and Pioneers 10 and 11 spacecraft in 1974 allows a nearly unambiguous, empirical study of the radial evolution of the interaction regions of two contrasting weak and strong, giant streams. The study confirms the main aspects of the standard model of corotating interaction regions: an expanding and strengthening pair of forward-reverse shocks sandwich a stream interface. It adds the follwoing concepts: stream group speed--the speed at the stream interface tends to remain constant with distance; corotating stream complexes--interaction regions can include features like noncompressive density enhancements and streamer belts; secondary interfaces--a possible precursor to the reverse shock; and emerging stream interfaces--one emerged between 1 AU and 4.6 AU. The study uses the conservation specific entropy to correlate features between spacecraft.

  11. Di-hadron correlations with identified leading hadrons in 200 GeV Au + Au and d + Au collisions at STAR

    NASA Astrophysics Data System (ADS)

    Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Alekseev, I.; Aparin, A.; Arkhipkin, D.; Aschenauer, E. C.; Averichev, G. S.; Bai, X.; Bairathi, V.; Banerjee, A.; Bellwied, R.; Bhasin, A.; Bhati, A. K.; Bhattarai, P.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Bordyuzhin, I. G.; Bouchet, J.; Brandenburg, D.; Brandin, A. V.; Bunzarov, I.; Butterworth, J.; Caines, H.; Calderón de la Barca Sánchez, M.; Campbell, J. M.; Cebra, D.; Cervantes, M. C.; Chakaberia, I.; Chaloupka, P.; Chang, Z.; Chattopadhyay, S.; Chen, X.; Chen, J. H.; Cheng, J.; Cherney, M.; Christie, W.; Contin, G.; Crawford, H. J.; Das, S.; De Silva, L. C.; Debbe, R. R.; Dedovich, T. G.; Deng, J.; Derevschikov, A. A.; di Ruzza, B.; Didenko, L.; Dilks, C.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Du, C. M.; Dunkelberger, L. E.; Dunlop, J. C.; Efimov, L. G.; Engelage, J.; Eppley, G.; Esha, R.; Evdokimov, O.; Eyser, O.; Fatemi, R.; Fazio, S.; Federic, P.; Fedorisin, J.; Feng, Z.; Filip, P.; Fisyak, Y.; Flores, C. E.; Fulek, L.; Gagliardi, C. A.; Garand, D.; Geurts, F.; Gibson, A.; Girard, M.; Greiner, L.; Grosnick, D.; Gunarathne, D. S.; Guo, Y.; Gupta, S.; Gupta, A.; Guryn, W.; Hamad, A.; Hamed, A.; Haque, R.; Harris, J. W.; He, L.; Heppelmann, S.; Heppelmann, S.; Hirsch, A.; Hoffmann, G. W.; Hofman, D. J.; Horvat, S.; Huang, T.; Huang, B.; Huang, H. Z.; Huang, X.; Huck, P.; Humanic, T. J.; Igo, G.; Jacobs, W. W.; Jang, H.; Jia, J.; Jiang, K.; Judd, E. G.; Kabana, S.; Kalinkin, D.; Kang, K.; Kauder, K.; Ke, H. W.; Keane, D.; Kechechyan, A.; Khan, Z. H.; Kikoła, D. P.; Kisiel, A.; Kochenda, L.; Koetke, D. D.; Kosarzewski, L. K.; Kraishan, A. F.; Kravtsov, P.; Krueger, K.; Kumar, L.; Lamont, M. A. C.; Landgraf, J. M.; Landry, K. D.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, J. H.; Li, X.; Li, W.; Li, Z. M.; Li, Y.; Li, C.; Li, X.; Lisa, M. A.; Liu, F.; Ljubicic, T.; Llope, W. J.; Lomnitz, M.; Longacre, R. S.; Luo, X.; Ma, G. L.; Ma, Y. G.; Ma, R.; Ma, L.; Magdy, N.; Majka, R.; Manion, A.; Margetis, S.; Markert, C.; Masui, H.; Matis, H. S.; McDonald, D.; Meehan, K.; Mei, J. C.; Minaev, N. G.; Mioduszewski, S.; Mishra, D.; Mohanty, B.; Mondal, M. M.; Morozov, D. A.; Mustafa, M. K.; Nandi, B. K.; Nasim, Md.; Nayak, T. K.; Nigmatkulov, G.; Niida, T.; Nogach, L. V.; Noh, S. Y.; Novak, J.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Oh, K.; Okorokov, V.; Olvitt, D.; Page, B. S.; Pak, R.; Pan, Y. X.; Pandit, Y.; Panebratsev, Y.; Pawlik, B.; Pei, H.; Perkins, C.; Peterson, A.; Pile, P.; Pluta, J.; Poniatowska, K.; Porter, J.; Posik, M.; Poskanzer, A. M.; Pruthi, N. K.; Putschke, J.; Qiu, H.; Quintero, A.; Ramachandran, S.; Raniwala, R.; Raniwala, S.; Ray, R. L.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Roy, A.; Ruan, L.; Rusnak, J.; Rusnakova, O.; Sahoo, N. R.; Sahu, P. K.; Sakrejda, I.; Salur, S.; Sandweiss, J.; Sarkar, A.; Schambach, J.; Scharenberg, R. P.; Schmah, A. M.; Schmidke, W. B.; Schmitz, N.; Seger, J.; Seyboth, P.; Shah, N.; Shahaliev, E.; Shanmuganathan, P. V.; Shao, M.; Sharma, B.; Sharma, M. K.; Shen, W. Q.; Shi, S. S.; Shou, Q. Y.; Sichtermann, E. P.; Sikora, R.; Simko, M.; Singha, S.; Skoby, M. J.; Smirnov, N.; Smirnov, D.; Song, L.; Sorensen, P.; Spinka, H. M.; Srivastava, B.; Stanislaus, T. D. S.; Stepanov, M.; Strikhanov, M.; Stringfellow, B.; Sumbera, M.; Summa, B.; Sun, Y.; Sun, Z.; Sun, X. M.; Sun, X.; Surrow, B.; Svirida, D. N.; Szelezniak, M. A.; Tang, A. H.; Tang, Z.; Tarnowsky, T.; Tawfik, A.; Thomas, J. H.; Timmins, A. R.; Tlusty, D.; Todoroki, T.; Tokarev, M.; Trentalange, S.; Tribble, R. E.; Tribedy, P.; Tripathy, S. K.; Tsai, O. D.; Ullrich, T.; Underwood, D. G.; Upsal, I.; Van Buren, G.; van Nieuwenhuizen, G.; Vandenbroucke, M.; Varma, R.; Vasiliev, A. N.; Vertesi, R.; Videbæk, F.; Viyogi, Y. P.; Vokal, S.; Voloshin, S. A.; Vossen, A.; Wang, J. S.; Wang, F.; Wang, H.; Wang, G.; Wang, Y.; Wang, Y.; Webb, G.; Webb, J. C.; Wen, L.; Westfall, G. D.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, Y. F.; Wu; Xiao, Z. G.; Xie, W.; Xin, K.; Xu, H.; Xu, Z.; Xu, Q. H.; Xu, Y. F.; Xu, N.; Yang, S.; Yang, Y.; Yang, Q.; Yang, Y.; Yang, C.; Yang, Y.; Ye, Z.; Ye, Z.; Yepes, P.; Yi, L.; Yip, K.; Yoo, I.-K.; Yu, N.; Zbroszczyk, H.; Zha, W.; Zhang, Y.; Zhang, Z.; Zhang, J. B.; Zhang, J.; Zhang, X. P.; Zhang, S.; Zhang, J.; Zhao, J.; Zhong, C.; Zhou, L.; Zhu, X.; Zoulkarneeva, Y.

    2015-12-01

    The STAR Collaboration presents for the first time two-dimensional di-hadron correlations with identified leading hadrons in 200 GeV central Au + Au and minimum-bias d + Au collisions to explore hadronization mechanisms in the quark gluon plasma. The enhancement of the jet-like yield for leading pions in Au + Au data with respect to the d + Au reference and the absence of such an enhancement for leading non-pions (protons and kaons) are discussed within the context of a quark recombination scenario. The correlated yield at large angles, specifically in the ridge region, is found to be significantly higher for leading non-pions than pions. The consistencies of the constituent quark scaling, azimuthal harmonic model and a mini-jet modification model description of the data are tested, providing further constraints on hadronization.

  12. From the ternary Eu(Au/In)2 and EuAu4(Au/In)2 with remarkable Au/In distributions to a new structure type: The gold-rich Eu5Au16(Au/In)6 structure

    DOE PAGESBeta

    Steinberg, Simon; Card, Nathan; Mudring, Anja -Verena

    2015-08-13

    The ternary Eu(Au/In)2 (EuAu0.46In1.54(2)) (I), EuAu4(Au/In)2 (EuAu4+xIn2–x with x = 0.75(2) (II), 0.93(2), and 1.03(2)), and Eu5Au16(Au/In)6 (Eu5Au17.29In4.71(3)) (III) have been synthesized, and their structures were characterized by single-crystal X-ray diffraction. I and II crystallize with the CeCu2-type (Pearson Symbol oI12; Imma; Z = 4; a = 4.9018(4) Å; b = 7.8237(5) Å; c = 8.4457(5) Å) and the YbAl4Mo2-type (tI14; I4/mmm; Z = 2; a = 7.1612(7) Å; c = 5.5268(7) Å) and exhibit significant Au/In disorder. I is composed of an Au/In-mixed diamond-related host lattice encapsulating Eu atoms, while the structure of II features ribbons of distorted, squaredmore » Au8 prisms enclosing Eu, Au, and In atoms. Combination of these structural motifs leads to a new structure type as observed for Eu5Au16(Au/In)6 (Eu5Au17.29In4.71(3)) (oS108; Cmcm; Z = 4; a = 7.2283(4) Å; b = 9.0499(6) Å; c = 34.619(2) Å), which formally represents a one-dimensional intergrowth of the series EuAu2–“EuAu4In2”. The site preferences of the disordered Au/In positions in II were investigated for different hypothetical “EuAu4(Au/In)2” models using the projector-augmented wave method and indicate that these structures attempt to optimize the frequencies of the heteroatomic Au–In contacts. Furthermore, a chemical bonding analysis on two “EuAu5In” and “EuAu4In2” models employed the TB-LMTO-ASA method and reveals that the subtle interplay between the local atomic environments and the bond energies determines the structural and site preferences for these systems.« less

  13. Enhanced spin pumping at yttrium iron garnet/Au interfaces

    SciTech Connect

    Burrowes, C.; Heinrich, B.; Kardasz, B.; Montoya, E. A.; Girt, E.; Sun Yiyan; Song, Young-Yeal; Wu Mingzhong

    2012-02-27

    Spin injection across the ferrimagnetic insulator yttrium iron garnet (YIG)/normal metal Au interface was studied using ferromagnetic resonance. The spin mixing conductance was determined by comparing the Gilbert damping parameter {alpha} in YIG/Au and YIG/Au/Fe heterostructures. The main purpose of this study was to correlate the spin pumping efficiency with chemical modifications of the YIG film surface using in situ etching and deposition techniques. By means of Ar{sup +} ion beam etching, one is able to increase the spin mixing conductance at the YIG/Au interface by a factor of 5 compared to the untreated YIG/Au interface.

  14. Thermal Desorption of Au from W(001) Surface

    NASA Astrophysics Data System (ADS)

    Błaszczyszyn, R.; Chrzanowski, J.; Godowski, P. J.

    2000-12-01

    Adsorption of Au on W(001) at 450 K up to multilayer structures was investigated. Temperature programmed desorption technique was used in determination of coverage dependent desorption energy (region up to one monolayer). Results were discussed in terms of competitive interactions of Au--Au and Au--W atoms. Simple procedure for prediction of faceting behavior on the interface, basing on the desorption data, was postulated. It was deduced that the Au/W(001) interface should not show faceting tendency after thermal treatment.

  15. First results on d+Au collisions from PHOBOS

    NASA Astrophysics Data System (ADS)

    Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Becker, B.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; García, E.; Gburek, T.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Harrington, A. S.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Khan, N.; Kulinich, P.; Kuo, C. M.; Lee, J. W.; Lin, W. T.; Manly, S.; Mignerey, A. C.; Noell, A.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Roland, C.; Roland, G.; Sagerer, J.; Sarin, P.; Sawicki, P.; Sedykh, I.; Skulski, W.; Smith, C. E.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Teng, R.; Tonjes, M. B.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Veres, G. I.; Wadsworth, B.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.; Zhang, J.

    2004-02-01

    We have measured transverse momentum distributions of charged hadrons produced in d+Au collisions at √SNN = 200 GeV, in the range 0.25 < pT < 6.0 GeV/c. With increasing collision centrality, the yield at high transverse momenta increases more rapidly than the overall particle density, leading to a strong modification of the spectral shape. This change in spectral shape is qualitatively different from observations in Au+Au collisions at the same energy. The results provide important information for discriminating between different models for the suppression of high-pT hadrons observed in Au+Au collisions.

  16. Surface effects on the radiation response of nanoporous Au foams

    SciTech Connect

    Fu, E. G.; Caro, M.; Wang, Y. Q.; Baldwin, K.; Caro, A.; Zepeda-Ruiz, L. A.; Bringa, E.; Nastasi, M.

    2012-11-05

    We report on an experimental and simulation campaign aimed at exploring the radiation response of nanoporous Au (np-Au) foams. We find different defect accumulation behavior by varying radiation dose-rate in ion-irradiated np-Au foams. Stacking fault tetrahedra are formed when np-Au foams are irradiated at high dose-rate, but they do not seem to be formed in np-Au at low dose-rate irradiation. A model is proposed to explain the dose-rate dependent defect accumulation based on these results.

  17. Synthesis, structure, and bonding in K12Au21Sn4. A polar intermetallic compound with dense Au20 and open AuSn4 layers

    SciTech Connect

    Li, Bin; Kim, Sung-Jin; Miller, Gordon J.; and Corbett, John D.

    2009-10-29

    The new phase K{sub 12}Au{sub 21}Sn{sub 4} has been synthesized by direct reaction of the elements at elevated temperatures. Single crystal X-ray diffraction established its orthorhombic structure, space group Pmmn (No. 59), a = 12.162(2); b = 18.058(4); c = 8.657(2) {angstrom}, V = 1901.3(7) {angstrom}{sup 3}, and Z = 2. The structure consists of infinite puckered sheets of vertex-sharing gold tetrahedra (Au{sub 20}) that are tied together by thin layers of alternating four-bonded-Sn and -Au atoms (AuSn{sub 4}). Remarkably, the dense but electron-poorer blocks of Au tetrahedra coexist with more open and saturated Au-Sn layers, which are fragments of a zinc blende type structure that maximize tetrahedral heteroatomic bonding outside of the network of gold tetrahedra. LMTO band structure calculations reveal metallic properties and a pseudogap at 256 valence electrons per formula unit, only three electrons fewer than in the title compound and at a point at which strong Au-Sn bonding is optimized. Additionally, the tight coordination of the Au framework atoms by K plays an important bonding role: each Au tetrahedra has 10 K neighbors and each K atom has 8-12 Au contacts. The appreciably different role of the p element Sn in this structure from that in the triel members in K{sub 3}Au{sub 5}In and Rb{sub 2}Au{sub 3}Tl appears to arise from its higher electron count which leads to better p-bonding (valence electron concentrations = 1.32 versus 1.22).

  18. Isomorphism and solid solutions among Ag- and Au-selenides

    NASA Astrophysics Data System (ADS)

    Palyanova, Galina A.; Seryotkin, Yurii V.; Kokh, Konstantin A.; Bakakin, Vladimir V.

    2016-09-01

    Au-Ag selenides were synthesized by heating stoichiometric mixtures of elementary substances of initial compositions Ag2-xAuxSe with a step of x=0.25 (0≤x≤2) to 1050 °C and annealing at 500 °C. Scanning electron microscopy, optical microscopy, electron microprobe analysis and X-ray powder diffraction methods have been applied to study synthesized samples. Results of studies of synthesized products revealed the existence of three solid solutions with limited isomorphism Ag↔Au: naumannite Ag2Se - Ag1.94Au0.06Se, fischesserite Ag3AuSe2 - Ag3.2Au0.8Se2 and gold selenide AuSe - Au0.94Ag0.06Se. Solid solutions and AgAuSe phases were added to the phase diagram of Ag-Au-Se system. Crystal-chemical interpretation of Ag-Au isomorphism in selenides was made on the basis of structural features of fischesserite, naumannite, and AuSe.

  19. Direct Observation of Au Nanoclusters at Au/Si Interface and Enhanced SiO2 Growth Due to Catalytic Action by Au in Thermally Oxidized Au-Precipitated n-Type Si(001) Surfaces

    NASA Astrophysics Data System (ADS)

    Shimizu, Hirofumi; Kumamoto, Akihito; Imamura, Senji

    2013-04-01

    The behavior of Au nanoclusters at a Au/n-Si interface was investigated. In particular, SiO2 growth in thermally oxidized Au-precipitated n-type Si(001) surfaces was enhanced by the catalytic action of Au. When the Au-precipitated Si wafer was exposed to air for 30 d at room temperature (RT), a SiO2 film layer grew over Au nanoclusters on the Si surface. This is possibly because Si atoms may diffuse in an as-deposited Au layer and are oxidized in air at RT. In the case of oxidation at higher temperatures (850 °C for 30 min), Au nanoclusters were found to exist at the Au/n-Si interface. Moreover, the origin of protuberances observed by atomic force microscopy was found to be a bulge in the SiO2 film formed over the Au nanocluster, proving that the growth of the SiO2 film layer was enhanced by the catalytic action of Au.

  20. [Gold antirheumatic drug: desired and adverse effects of Au(I) and Au(III) [corrected] on the immune system.

    PubMed

    Griem, P; Gleichmann, E

    1996-01-01

    Three new findings are reviewed that help to understand the mechanisms of action of anti-rheumatic gold drugs, such as disodium aurothiomalate (Na2Au(I)TM): i) We found that Na2Au(I)TM selectively inhibits T-cell receptor-mediated antigen recognition by murine CD4+ T-cell hybridomas specific for antigenic peptides containing at least two cysteine residues. Presumably, Au(I) acts as a chelating agent forming linear complexes (Cys-Au(I)-Cys) which prevents correct antigen-processing and/or peptide recognition by the T-cell receptor, ii) We were able to show that Au(I) is oxidized to Au(III) in mononuclear phagocytes, such as macrophages. Because Au(III) rapidly oxidizes protein and itself is re-reduced to Au(I), this may introduce an Au(I)/Au(III) redox system into phagocytes which scavenges reactive oxygen species, such as hypochlorous acid (HOCl) and inactivates lysosomal enzymes, iii) Pretreatment with Au(III) of a model protein antigen, bovine ribonuclease A (RNase A), induced novel antigenic determinants recognized by CD4+ T lymphocytes. Analysis of the fine specificity of these "Au(III)-specific" T-cells revealed that they react to RNase peptides that are not presented to T-cells when the native protein, i.e., not treated with Au(III), is used as antigen. The T-cell recognition of these cryptic peptides did not require the presence of gold. This finding has important implications for understanding the pathogenesis of allergic and autoimmune responses induced by gold drugs. Taken together, our findings indicate that Au(I) and Au(III) each exert specific effects on several distinct functions of macrophages and the activation of T-cells. These effects may explain both the desired anti-inflammatory and the adverse effects of antirheumatic gold drugs. PMID:9036720

  1. Au-nanoparticles grafted on plasma treated PE

    NASA Astrophysics Data System (ADS)

    Švorčík, V.; Chaloupka, A.; Řezanka, P.; Slepička, P.; Kolská, Z.; Kasálková, N.; Hubáček, T.; Siegel, J.

    2010-03-01

    Polyethylene (PE) surface was treated with Ar plasma. Activated surface was grafted from methanol solution of 1,2-ethanedithiol. Then the sample was immersed into freshly prepared colloid solution of Au-nanoparticles. Finally Au layer was sputtered on the samples. Properties of the modified PE were studied using various methods: AFM, EPR, RBS and nanoindentation. It was shown that the plasma treatment results in degradation of polymer chain (AFM) and creation of free radicals by EPR. After grafting with dithiol, the concentration of free radicals declines. The presence of Au and S in the surface layer after the coating with Au-nanoparticles was proved by RBS. Plasma treatment changes PE surface morphology and increases surface roughness, too. Another significant change in surface morphology and roughness was observed after deposition of Au-nanoparticles. Nanoindentation measurements show that the grafting with Au-nanoparticles increases adhesion of subsequently sputtered Au layer.

  2. Collision-spike Sputtering of Au Nanoparticles.

    PubMed

    Sandoval, Luis; Urbassek, Herbert M

    2015-12-01

    Ion irradiation of nanoparticles leads to enhanced sputter yields if the nanoparticle size is of the order of the ion penetration depth. While this feature is reasonably well understood for collision-cascade sputtering, we explore it in the regime of collision-spike sputtering using molecular-dynamics simulation. For the particular case of 200-keV Xe bombardment of Au particles, we show that collision spikes lead to abundant sputtering with an average yield of 397 ± 121 atoms compared to only 116 ± 48 atoms for a bulk Au target. Only around 31 % of the impact energy remains in the nanoparticles after impact; the remainder is transported away by the transmitted projectile and the ejecta. The sputter yield of supported nanoparticles is estimated to be around 80 % of that of free nanoparticles due to the suppression of forward sputtering. PMID:26245857

  3. Collision-spike sputtering of Au nanoparticles

    SciTech Connect

    Sandoval, Luis; Urbassek, Herbert M.

    2015-08-06

    Ion irradiation of nanoparticles leads to enhanced sputter yields if the nanoparticle size is of the order of the ion penetration depth. While this feature is reasonably well understood for collision-cascade sputtering, we explore it in the regime of collision-spike sputtering using molecular-dynamics simulation. For this specific case of 200-keV Xe bombardment of Au particles, we show that collision spikes lead to abundant sputtering with an average yield of 397 ± 121 atoms compared to only 116 ± 48 atoms for a bulk Au target. Only around 31% of the impact energy remains in the nanoparticles after impact; the remainder is transported away by the transmitted projectile and the ejecta. The sputter yield of supported nanoparticles is estimated to be around 80% of that of free nanoparticles due to the suppression of forward sputtering.

  4. Collision-spike sputtering of Au nanoparticles

    DOE PAGESBeta

    Sandoval, Luis; Urbassek, Herbert M.

    2015-08-06

    Ion irradiation of nanoparticles leads to enhanced sputter yields if the nanoparticle size is of the order of the ion penetration depth. While this feature is reasonably well understood for collision-cascade sputtering, we explore it in the regime of collision-spike sputtering using molecular-dynamics simulation. For this specific case of 200-keV Xe bombardment of Au particles, we show that collision spikes lead to abundant sputtering with an average yield of 397 ± 121 atoms compared to only 116 ± 48 atoms for a bulk Au target. Only around 31% of the impact energy remains in the nanoparticles after impact; the remaindermore » is transported away by the transmitted projectile and the ejecta. The sputter yield of supported nanoparticles is estimated to be around 80% of that of free nanoparticles due to the suppression of forward sputtering.« less

  5. Tunable VO2/Au hyperbolic metamaterial

    NASA Astrophysics Data System (ADS)

    Prayakarao, S.; Mendoza, B.; Devine, A.; Kyaw, C.; van Dover, R. B.; Liberman, V.; Noginov, M. A.

    2016-08-01

    Vanadium dioxide (VO2) is known to have a semiconductor-to-metal phase transition at ˜68 °C. Therefore, it can be used as a tunable component of an active metamaterial. The lamellar metamaterial studied in this work is composed of subwavelength VO2 and Au layers and is designed to undergo a temperature controlled transition from the optical hyperbolic phase to the metallic phase. VO2 films and VO2/Au lamellar metamaterial stacks have been fabricated and studied in electrical conductivity and optical (transmission and reflection) experiments. The observed temperature-dependent changes in the reflection and transmission spectra of the metamaterials and VO2 thin films are in a good qualitative agreement with theoretical predictions. The demonstrated optical hyperbolic-to-metallic phase transition is a unique physical phenomenon with the potential to enable advanced control of light-matter interactions.

  6. A pilot cohort study to assess the feasibility of HIV prevention science research among men who have sex with men in Dakar, Senegal

    PubMed Central

    Dramé, Fatou Maria; Crawford, Emily E; Diouf, Daouda; Beyrer, Chris; Baral, Stefan D

    2013-01-01

    Introduction Men who have sex with men (MSM) are disproportionately burdened by HIV in Senegal, across sub-Saharan Africa and throughout the world. This is driven in part by stigma, and limits health achievements and social capital among these populations. To date, there is a limited understanding of the feasibility of prospective HIV prevention studies among MSM in Senegal, including HIV incidence and cohort retention rates. Methods One hundred and nineteen men who reported having anal sex with another man in the past 12 months were randomly selected from a sampling frame of 450 unique members of community groups serving MSM in Dakar. These men were enrolled in a 15-month pilot cohort study implemented by a community-based partner. The study included a structured survey instrument and biological testing for HIV, syphilis and hepatitis B virus at two time points. Results Baseline HIV prevalence was 36.0% (43/114), with cumulative HIV prevalence at study end being 47.2% (51/108). The annualized incidence rate was 16% (8/40 at risk for seroconversion over 15 months of follow-up, 95% confidence interval 4.6–27.4%). Thirty-seven men were lost to follow up, including at least four deaths. Men who were able to confide in someone about health, emotional distress and sex were less likely to be HIV positive (OR 0.36, p < 0.05, 95% CI 0.13, 0.97). Conclusions High HIV prevalence and incidence, as well as mortality in this young population of Senegalese MSM indicate a public health emergency. Moreover, given the high burden of HIV and rate of incident HIV infections, this population appears to be appropriate for the evaluation of novel HIV prevention, treatment and care approaches. Using a study implemented by community-based organizations, there appears to be feasibility in implementing interventions addressing the multiple levels of HIV risk among MSM in this setting. However, low retention across arms of this pilot intervention, and in the cohort, will need to be

  7. Plasmodium falciparum susceptibility to anti-malarial drugs in Dakar, Senegal, in 2010: an ex vivo and drug resistance molecular markers study

    PubMed Central

    2013-01-01

    Background In 2006, the Senegalese National Malaria Control Programme recommended artemisinin-based combination therapy (ACT) as the first-line treatment for uncomplicated malaria. Since the introduction of ACT, there have been very few reports on the level of resistance of P. falciparum to anti-malarial drugs. To determine whether parasite susceptibility has been affected by the new anti-malarial policies, an ex vivo susceptibility and drug resistance molecular marker study was conducted on local isolates obtained from the Centre de santé Elizabeth Diouf (Médina, Dakar, Senegal). Methods The prevalence of genetic polymorphisms in genes associated with anti-malarial drug resistance, i.e., pfcrt, pfdhfr, pfdhps and pfmdr1, were evaluated for a panel of 165 isolates collected from patients recruited from 17 August 2010 to 6 January 2011. The malaria isolates were assessed for susceptibility to chloroquine (CQ); quinine (QN); monodesethylamodiaquine (MDAQ), the active metabolite of amodiaquine; mefloquine (MQ); lumefantrine (LMF); dihydroartemisinin (DHA), the active metabolite of artemisinin derivatives; and doxycycline (DOX) using the Plasmodium lactate dehydrogenase (pLDH) ELISA. Results The prevalence of the in vitro resistant isolates, or isolates with reduced susceptibility, was 62.1% for MQ, 24.2% for CQ, 10.3% for DOX, 11.8% MDAQ, 9.7% for QN, 2.9% for LMF and 0% for DHA. The Pfcrt 76T mutation was identified in 43.6% of the samples. The pfmdr1 86Y, 184F and 1246Y mutations were found in 16.2%, 50.0% and 1.6% of the samples, respectively. The pfdhfr 108N, 51I and 59R mutations were identified in 81.9%, 77.4% and 79.4% of the samples, respectively. The double mutant (108N and 51I) was detected in 75.5% of the isolates, and the triple mutant (108N, 51I and 59R) was detected in 73.6% of the isolates. The pfdhps 437G, 436A and 613S mutations were found in 54.4%, 38.6% and 1.2% of the samples, respectively. There was only one double mutant, 437G and 540E, and one

  8. Non-stationary analysis of dry spells in monsoon season of Senegal River Basin using data from Regional Climate Models (RCMs)

    NASA Astrophysics Data System (ADS)

    Giraldo Osorio, J. D.; García Galiano, S. G.

    2012-07-01

    SummaryThe Senegal River Basin, located in West Africa, has been affected by several droughts since the end of the 1960s. In its valley, which is densely populated and highly vulnerable to climate variability and water availability, agricultural activities provide the livelihood for thousands of people. Increasing the knowledge about plausible trends of drought events will allow to improve the adaptation and mitigation measures in order to build "adaptive capacity" to climate change in West Africa. An innovative methodology for the non-stationary analysis of droughts events, which allows the prediction of regional trends associated to several return periods, is presented. The analyses were based on Regional Climate Models (RCMs) provided by the European ENSEMBLES project for West Africa, together with observed data. A non-stationary behaviour of the annual series of maximum length of dry spells (AMDSL) in the monsoon season is reflected in temporal changes in mean and variance. The non-stationary nature of hydrometeorological series, due to climate change and anthropogenic activities, is the main criticism to traditional frequency analysis. Therefore, in this paper, the modelling tool GAMLSS (Generalized Additive Models for Location, Scale and Shape), is applied to develop regional probability density functions (pdfs) fitted to AMDSL series for the monsoon season in the Senegal River Basin. The skills of RCMs in the representation of maximum length of dry spells observed for the period 1970-1990, are evaluated considering observed data. Based on the results obtained, a first selection of the RCMs with which to apply GAMLSS to the AMDSL series identified, for the time period 1970-2050, is made. The results of GAMLSS analysis exhibit divergent trends, with different value ranges for parameters of probability distributions being detected. Therefore, in the second stage of the paper, regional pdfs are constructed using bootstrapping distributions based on probabilistic

  9. Dramatic declines in seropositivity as determined with crude extracts of Plasmodium falciparum schizonts between 2000 and 2010 in Dielmo and Ndiop, Senegal

    PubMed Central

    2014-01-01

    Background Programmes of pre-elimination of malaria have been implemented in Senegal since 2010, and the burden of malaria has decreased substantially. These changes in the epidemiology should be monitored with effective tools that allow changes in patterns of transmission to be estimated. In Dielmo and Ndiop, two villages of Senegal with different malaria endemicity, infections have been followed longitudinally for 20 years, during which time there have been several control interventions leading to substantial decreases of transmission. This study aimed to compare malaria antibody responses of the inhabitants of these two villages, between 2000 and 2010, using schizont crude extracts of a local strain of P. falciparum (Pf Sch07/03). Methods Sera collected from inhabitants of the two villages (141 from Dielmo and 79 from Ndiop in 2000; 143 from Dielmo and 79 from Ndiop in 2010) were used to assess the prevalence of antibodies against crude schizont extracts of Pf Sch07/03. Three ages groups were defined: [5-9] yrs, [10-14] yrs and [15-19] yrs. Statistical comparisons were performed. Seroprevalence and the magnitude of antibody responses were compared between age groups, villages and periods. Results Overall seroprevalence to P.fSch07/03 decreased between 2000 and 2010 in both villages: from 94.4% to 44.4% in Dielmo and from 74.4% to 34.6% in Ndiop. The difference between Dielmo and Ndiop was highly significant in 2000 (p < 0.001) but not in 2010 (p >0.20). The decrease in seroprevalence was larger in younger (more than 40%) than older (less than 19%) inhabitants. Longitudinal monitoring of the younger group showed that seroprevalence decreased between 2000 and 2010 in Dielmo from 98.7 to 79.3, but not in Ndiop from 67.6 to 66.7. The magnitude of antibody responses in seropositive individuals was significantly higher in 2000 than 2010 for both villages. Conclusions Crude extracts of P. falciparum are appropriate tools for evaluating malaria prevalence at

  10. User-determined end of net life in Senegal: a qualitative assessment of decision-making related to the retirement of expired nets

    PubMed Central

    2013-01-01

    Background Procurement and distribution of long-lasting insecticidal nets (LLINs) in the African region has decreased from 145 million in 2010 to 66 million nets in 2012. As resources for LLIN distribution appear to stagnate, it is important to understand the users’ perception of the life span of a net and at what point and why they stop using it. In order to get the most value out of distributed nets and to ensure that they are used for as long as possible, programmes must communicate to users about how to assess useful net life and how to extend it. Methods Data were collected from 114 respondents who participated in 56 in-depth interviews (IDIs) and eight focus group discussions (FGDs) in August 2012 in eight regions in Senegal. Households were eligible for the study if they owned at least one net and had an available household member over the age of 18. Data were coded by a team of four coders in ATLAS.ti using a primarily deductive approach. Results Respondents reported assessing useful net life using the following criteria: the age of net, the number and size of holes and the presence of mosquitoes in the net at night. If they had the means to do so, many respondents preferred the acquisition of a new net rather than the continued use of a very torn net. However, respondents would preferentially use newer nets, saving older, but useable nets for the future or sharing them with family or friends. Participants reported observing alternative uses of nets, primarily for nets that were considered expired. Conclusions The results indicate that decisions regarding the end of net life vary among community members in Senegal, but are primarily related to net integrity. Additional research is needed into user-determined end of net life as well as care and repair behaviours, which could extend useful net life. The results from this study and from future research on this topic should be used to understand current behaviours and develop communication programmes to

  11. Assessing healthcare providers' knowledge and practices relating to insecticide-treated nets and the prevention of malaria in Ghana, Laos, Senegal and Tanzania

    PubMed Central

    2011-01-01

    Background Research evidence is not always being disseminated to healthcare providers who need it to inform their clinical practice. This can result in the provision of ineffective services and an inefficient use of resources, the implications of which might be felt particularly acutely in low- and middle-income countries. Malaria prevention is a particularly compelling domain to study evidence/practice gaps given the proven efficacy, cost-effectiveness and disappointing utilization of insecticide-treated nets (ITNs). Methods This study compares what is known about ITNs to the related knowledge and practices of healthcare providers in four low- and middle-income countries. A new questionnaire was developed, pilot tested, translated and administered to 497 healthcare providers in Ghana (140), Laos (136), Senegal (100) and Tanzania (121). Ten questions tested participants' knowledge and clinical practice related to malaria prevention. Additional questions addressed their individual characteristics, working context and research-related activities. Ordinal logistic regressions with knowledge and practices as the dependent variable were conducted in addition to descriptive statistics. Results The survey achieved a 75% response rate (372/497) across Ghana (107/140), Laos (136/136), Senegal (51/100) and Tanzania (78/121). Few participating healthcare providers correctly answered all five knowledge questions about ITNs (13%) or self-reported performing all five clinical practices according to established evidence (2%). Statistically significant factors associated with higher knowledge within each country included: 1) training in acquiring systematic reviews through the Cochrane Library (OR 2.48, 95% CI 1.30-4.73); and 2) ability to read and write English well or very well (OR 1.69, 95% CI 1.05-2.70). Statistically significant factors associated with better clinical practices within each country include: 1) reading scientific journals from their own country (OR 1.67, 95% CI

  12. Resistance to DDT and Pyrethroids and Increased kdr Mutation Frequency in An. gambiae after the Implementation of Permethrin-Treated Nets in Senegal

    PubMed Central

    Ndiath, Mamadou O.; Sougoufara, Seynabou; Gaye, Abdoulaye; Mazenot, Catherine; Konate, Lassana; Faye, Oumar; Sokhna, Cheikh; Trape, Jean-Francois

    2012-01-01

    Introduction The aim of this study was to evaluate the susceptibility to insecticides of An. gambiae mosquitoes sampled in Dielmo (Senegal), in 2010, 2 years after the implementation of Long Lasting Insecticide-treated Nets (LLINs) and to report the evolution of kdr mutation frequency from 2006 to 2010. Methods WHO bioassay susceptibility tests to 6 insecticides were performed on adults F0, issuing from immature stages of An. gambiae s.l., sampled in August 2010. Species and molecular forms as well as the presence of L1014F and L1014S kdr mutations were assessed by PCR. Longitudinal study of kdr mutations was performed on adult mosquitoes sampled monthly by night landing catches from 2006 to 2010. Findings No specimen studied presented the L1014S mutation. During the longitudinal study, L1014F allelic frequency rose from 2.4% in year before the implementation of LLINs to 4.6% 0–12 months after and 18.7% 13–30 months after. In 2010, An. gambiae were resistant to DDT, Lambda-cyhalothrin, Deltamethrin and Permethrin (mortality rates ranging from 46 to 63%) but highly susceptible to Fenitrothion and Bendiocarb (100% mortality). There was significantly more RR genotype among An. gambiae surviving exposure to DDT or Pyrethroids. An. arabiensis represented 3.7% of the sampled mosquitoes (11/300) with no kdr resistance allele detected. An. gambiae molecular form M represented 29.7% of the mosquitoes with, among them, kdr genotypes SR (18%) and SS (82%). An. gambiae molecular form S represented 66% of the population with, among them, kdr genotype SS (33.3%), SR (55.6%) and RR (11.1%). Only 2 MS hybrid mosquitoes were sampled and presented SS kdr genotype. Conclusion Biological evidence of resistance to DDT and pyrethroids was detected among An. gambiae mosquitoes in Dielmo (Senegal) within 24 months of community use of LLINs. Molecular identification of L1014F mutation indicated that target site resistance increased after the implementation of LLINs. PMID:22384107

  13. Analysis of the residual linewidth in electron-paramagnetic resonance of AuEr and AuYb

    NASA Astrophysics Data System (ADS)

    Spalden, Y. von; Baberschke, K.

    1981-04-01

    For single crystals of AuEr and polycrystalline AuYb the residual EPR linewidth due to inhomogeneous broadening is analyzed. Angular dependent experiments show uniquely that the main contribution is due to internal strain rather than to dipolar interaction. The independent experiments for AuEr and AuYb yield a consistent set of parameters but show a dipolar contribution two to three times smaller than calculated. An explanation for this is given. The very precise determination of Hres yields |Δg | = |ρJ1| < 0.005 for AuEr, a vanishing g-shift.

  14. Thermal stability of sputtered intermetallic Al-Au coatings

    SciTech Connect

    Moser, M.; Mayrhofer, P. H.; Ross, I. M.; Rainforth, W. M.

    2007-09-15

    Recently, the authors have shown that single-phase Al{sub 2}Au coatings, prepared by unbalanced magnetron sputtering, exhibit a dense columnar structure and highest hardness and indentation moduli of 8 and 144 GPa, respectively, within the Al-Au films investigated. This study focuses on the thermal stability of Al{sub 2}Au with respect to films containing more Al and Au having Al/Au at. % ratios of 4.32 and 1.85, respectively. Single-phase Al{sub 2}Au has the highest onset temperature for recovery of 475 deg. C and recrystallization of 575 deg. C. Upon annealing Au- and Al-rich films, their stresses deviate from the linear thermoelastic behavior at temperatures (T) above 200 and 450 deg. C, respectively, due to pores and metallic phases present. Metastable Au within the as-deposited Au-rich film is consumed by the growing intermetallic AlAu and AlAu{sub 2} phases at T{>=}450 deg. C, which themselves melt at {approx}625 deg. C. Due to nanometer scale segregations of Al, encapsulated by Al{sub 2}Au in Al-rich coatings, their melting point is reduced by {approx}85 deg. C to 575 deg. C. Dynamic thermal analyses up to 1100 deg. C in synthetic air reveal the single-phase Al{sub 2}Au films with a superior thermal stability and only negligible oxidation. At 750 deg. C, the mass gain is {approx}1.5 mg/cm{sup 2} after 50 h isothermal exposure. Based on the investigations, the authors can conclude that single-phase intermetallic Al{sub 2}Au films have a high potential for oxidation protection of sensitive materials.

  15. Assembly of hybrid oligonucleotide modified gold (Au) and alloy nanoparticles building blocks.

    PubMed

    Kuo, Yu-Ching; Jen, Chun-Ping; Chen, Yu-Hung; Su, Chia-Hao; Tsai, Shu-Hui; Yeh, Chen-Sheng

    2006-01-01

    The alloy-based hybrid materials with macroscopic network arrays were developed by AuAg/Au and AuAgPd/Au nanoparticle composites through oligonucleotides hybridization. AuAg/Au and AuAgPd/Au exhibited distinct organization. The morphology of AuAg/Au conjugation assembled mainly as compact aggregates while AuAgPd/Au hybrid conjugated into the loosen network assemblies. The dehybridization temperatures were studied as a function of molar ratio of alloy/Au. It was found that higher alloy/gold molar ratio led to stronger hybridization for alloy/gold composite, accompanied with increased melting temperature. These results could be interpreted in terms of more alloy nanoparticles bound to a Au particle when the molar ratio of alloy/gold increased. The thermal analysis also showed that AuAg/Au exhibited higher dehybridization temperature. A modified model describing the dehybridization probability of an intact Au/alloy aggregate was performed to support the dehybridization temperature increased with increasing alloy/Au molar ratio. As to more oligonucleotides carried by AuAg (4.9 +/- 1.9 nm) than by AuAgPd (4.4 +/- 1.5 nm) due to larger size in AuAg, the efficient hybridization could result in higher dehybridization temperature in AuAg/Au. PMID:16573077

  16. Unwinding Au(+)···Au(+) Bonded Filaments in Ligand-Supported Gold(I) Polymer under Pressure.

    PubMed

    Paliwoda, Damian; Wawrzyniak, Paulina; Katrusiak, Andrzej

    2014-07-01

    The ultimately thin single-strand gold filaments, of Au(+)···Au(+) bonded gold(I) diethyldithiocarbamate polymer, AuEt2DTC, can be transformed depending on pressure and solvate contents. When synthesized in the presence of CH2Cl2, it crystallizes into a tetragonal AuEt2DTC·xCH2Cl2 phase α with ligand-supported and unsupported Au(+)···Au(+) bonded filaments modulated into molecular Au8-pitch helices. Low contents of CH2Cl2 favors the β phase of significantly reduced volume and orthorhombic space group Fddd. The α-AuEt2DTC·xCH2Cl2 crystal exhibits a highly unusual negative-area compressibility, due to the spring-like compression of helices. Above 0.05 GPa, the crystal transforms to phase β, where the Au16-pitch helices partly unwind their turns, which relaxes the tension generated by external pressure between neighboring helices of the opposite handedness. This is a unique observation of atomic-scale helical filaments transformation, which otherwise is a universal process analogous to the helix reversal between DNA forms B and Z, and in macroscopic world it is similar to nonperiodic unwind kinks in grapevine tendrils and telephone cords. Pressure also reduces the differences between the ligand-supported and unsupported Au(+)···Au(+) bonds. PMID:26279531

  17. Virus-templated Au and Au/Pt Core/shell Nanowires and Their Electrocatalytic Activitives for Fuel Cell Applications

    PubMed Central

    LEE, YOUJIN; KIM, JUNHYUNG; YUN, DONG SOO; NAM, YOON SUNG; SHAO-HORN, YANG; BELCHER, ANGELA M.

    2014-01-01

    A facile synthetic route was developed to make Au nanowires (NWs) from surfactant-mediated bio-mineralization of a genetically engineered M13 phage with specific Au binding peptides. From the selective interaction between Au binding M13 phage and Au ions in aqueous solution, Au NWs with uniform diameter were synthesized at room temperature with yields greater than 98 % without the need for size selection. The diameters of Au NWs were controlled from 10 nm to 50 nm. The Au NWs were found to be active for electrocatalytic oxidation of CO molecules for all sizes, where the activity was highly dependent on the surface facets of Au NWs. This low-temperature high yield method of preparing Au NWs was further extended to the synthesis of Au/Pt core/shell NWs with controlled coverage of Pt shell layers. Electro-catalytic studies of ethanol oxidation with different Pt loading showed enhanced activity relative to a commercial supported Pt catalyst, indicative of the dual functionality of Pt for the ethanol oxidation and Au for the anti-poisoning component of Pt. These new one-dimensional noble metal NWs with controlled compositions could facilitate the design of new alloy materials with tunable properties. PMID:24910712

  18. Simulation of Electric Field in Semi Insulating Au/CdTe/Au Detector under Flux

    SciTech Connect

    Franc, J.; James, R.; Grill, R.; Kubat, J.; Belas, E.; Hoschl, P.; Moravec, P.; Praus, P.

    2009-08-02

    We report our simulations on the profile of the electric field in semi insulating CdTe and CdZnTe with Au contacts under radiation flux. The type of the space charge and electric field distribution in the Au/CdTe/Au structure is at high fluxes result of a combined influence of charge formed due to band bending at the electrodes and from photo generated carriers, which are trapped at deep levels. Simultaneous solution of drift-diffusion and Poisson equations is used for the calculation. We show, that the space charge originating from trapped photo-carriers starts to dominate at fluxes 10{sup 15}-10{sup 16}cm{sup -2}s{sup -1}, when the influence of contacts starts to be negligible.

  19. Reporting Errors in Siblings’ Survival Histories and Their Impact on Adult Mortality Estimates: Results From a Record Linkage Study in Senegal

    PubMed Central

    Helleringer, Stéphane; Pison, Gilles; Kanté, Almamy M.; Duthé, Géraldine; Andro, Armelle

    2014-01-01

    Estimates of adult mortality in countries with limited vital registration (e.g., sub-Saharan Africa) are often derived from information about the survival of a respondent’s siblings. We evaluated the completeness and accuracy of such data through a record linkage study conducted in Bandafassi, located in southeastern Senegal. We linked at the individual level retrospective siblings’ survival histories (SSH) reported by female respondents (n = 268) to prospective mortality data and genealogies collected through a health and demographic surveillance system (HDSS). Respondents often reported inaccurate lists of siblings. Additions to these lists were uncommon, but omissions were frequent: respondents omitted 3.8 % of their live sisters, 9.1 % of their deceased sisters, and 16.6 % of their sisters who had migrated out of the DSS area. Respondents underestimated the age at death of the siblings they reported during the interview, particularly among siblings who had died at older ages (≥45 years). Restricting SSH data to person-years and events having occurred during a recent reference period reduced list errors but not age and date errors. Overall, SSH data led to a 20 % underestimate of 45q15 relative to HDSS data. Our study suggests new quality improvement strategies for SSH data and demonstrates the potential use of HDSS data for the validation of “unconventional” demographic techniques. PMID:24493063

  20. The social context of carbon sequestration: considerations from a multi-scale environmental history of the Old Peanut Basin of Senegal

    USGS Publications Warehouse

    Tschakert, P.; Tappan, G.

    2004-01-01

    This paper presents the results of a multi-scale investigation of environmental change in the Old Peanut Basin of Senegal throughout the 20th century. Based on historical accounts, ethnographies, aerial photos, satellite images, field and household surveys as well as various participatory research activities with farmers in selected villages, the study attempts to make explicit layered scales of analysis, both temporally and spatially. It shows that, despite some general trends of resource degradation in the Old Peanut Basin, local farming systems have embarked on different pathways of change to adapt to their evolving environment. It also illustrates that high diversity with respect to soil fertility management exists at the farm and household level. Finally, the paper proposes a farmer-oriented approach to carbon sequestration in order to integrate recommended technical options more efficiently into the complex and dynamic livelihoods of smallholders in dryland environments. This approach includes pathway-specific land use and management options at the level of farming systems and, at the level of individual households, a basket of possible practices from which farmers can choose depending on their multiple needs, capacities, and adaptive strategies to cope with risk and uncertainty.

  1. Of shifting economies and making ends meet: the changing role of the accompagnant at the Fann Psychiatric Clinic in Dakar, Senegal.

    PubMed

    Kilroy-Marac, Katie

    2014-09-01

    Since 1972, inpatients at the Fann Psychiatric Clinic have been required to have a family member or close friend--an accompagnant--stay with them for the duration of their hospitalization. In recent years, however, the role of the accompagnant has seen a dramatic transformation. This article considers the emergence of a new kind of accompagnant at Fann: the for-hire accompagnant mercenaire, who is unrelated to the patient and not employed by the clinic. Against the backdrop of Senegal's neoliberal turn and in light of the growing prominence of the biomedical approach at Fann, the author shows how the idealized accompagnant model of family caretaking has given way to this new form of commodified care. At the same time, however, the author argues that accompagnants mercenaires regularly draw upon and establish new sets of moral codes, obligations, debts, and expectations in their day-to-day interactions with patients, family members, and staff alike. By way of a careful ethnographic examination of the evolution of the accompagnant role at Fann, this article brings into focus a complex and multidimensional picture of the shifting economies--moral and political, as well as therapeutic--within the present-day clinic. PMID:25034610

  2. Territorial and land-use rights perspectives on human-chimpanzee-elephant coexistence in West Africa (Guinea, Guinea-Bissau, Senegal, nineteenth to twenty-first centuries).

    PubMed

    Leblan, Vincent

    2016-07-01

    The first part of this article compares the distribution of chimpanzee and elephant populations in reaction to human territorial dynamics of West African trade in parts of nineteenth century Guinea, Guinea-Bissau and Senegal. It answers for this specific region the question of whether present-day situations of close chimpanzee-human spatial proximity are stable or only temporary phenomena in long-term processes of environmental change, and shows that conservation policies centred on either of these two "flagship" species carry radically different ecological, political and territorial implications. The second part shifts to local-level perspectives on human-chimpanzee relationships, emphasizing the land rights contentions and misunderstandings created by the implementation of protected areas at Bossou and in the Boké region of Guinea. These case studies help to look at acts of resistance and local interpretations of primate conservation policies as opportunities to reconsider what is being protected, for what purpose, as whose heritage, and to move towards new and more legitimate opportunities for the implementation of conservation policies. PMID:27038218

  3. Preventive measures to prevent loss to follow-up in highly active antiretroviral therapy (HAART): implementing a strategy in Ziguinchor (Casamance, Senegal) in 2014.

    PubMed

    Randé, H; Rouffy, D

    2016-05-01

    Since 2010, the Pharmacie et Aide Humanitaire (PAH) in Casamance (Senegal) has been maintaining a software package (Tacojo) that allows monthly monitoring of the distribution of treatment to every patient with HIV infection receiving highly active antiretroviral therapy (HAART). We used this program to set up measures to prevent the loss to follow-up of patients receiving HAART. Our involvement focused on two main areas. First, each patient is routinely contacted after inclusion, to help us to understand the patient's experience of the disease and the treatment. This process aims to improve adherence to the treatment. Then, all patients who miss an appointment are routinely contacted by telephone within seven days of that appointment. The goal is to understand the reasons for the absence and to encourage patients to continue their treatment. Despite the lack of distance due to the relative newness of this program, these preventive measures have shown hopeful results (80% of the patients came back after a call). It would be interesting to apply it in a sustainable manner and in more medical facilities. PMID:27412981

  4. Vector competence of Aedes aegypti and Aedes vittatus (Diptera: Culicidae) from Senegal and Cape Verde archipelago for West African lineages of chikungunya virus.

    PubMed

    Diagne, Cheikh T; Faye, Oumar; Guerbois, Mathilde; Knight, Rachel; Diallo, Diawo; Faye, Ousmane; Ba, Yamar; Dia, Ibrahima; Faye, Ousmane; Weaver, Scott C; Sall, Amadou A; Diallo, Mawlouth

    2014-09-01

    To assess the risk of emergence of chikungunya virus (CHIKV) in West Africa, vector competence of wild-type, urban, and non-urban Aedes aegypti and Ae. vittatus from Senegal and Cape Verde for CHIKV was investigated. Mosquitoes were fed orally with CHIKV isolates from mosquitoes (ArD30237), bats (CS13-288), and humans (HD180738). After 5, 10, and 15 days of incubation following an infectious blood meal, presence of CHIKV RNA was determined in bodies, legs/wings, and saliva using real-time reverse transcription-polymerase chain reaction. Aedes vittatus showed high susceptibility (50-100%) and early dissemination and transmission of all CHIKV strains tested. Aedes aegypti exhibited infection rates ranging from 0% to 50%. Aedes aegypti from Cape Verde and Kedougou, but not those from Dakar, showed the potential to transmit CHIKV in saliva. Analysis of biology and competence showed relatively high infective survival rates for Ae. vittatus and Ae. aegypti from Cape Verde, suggesting their efficient vector capacity in West Africa. PMID:25002293

  5. Annulotrema (Monogenea: Dactylogyridae) from Hydrocynus brevis (Characiformes: Alestidae) in Senegal, with descriptions of two new species and remarks on Annulotrema pikei.

    PubMed

    Řehulková, Eva; Musilová, Naďa; Gelnar, Milan

    2014-09-01

    Two new species of Annulotrema Paperna & Thurston, 1969 were collected from the gills of the African tiger fish, Hydrocynus brevis, from the Gambia River basin in the Niokolo-Koba National Park, Senegal. Annulotrema besalis n. sp. is characterized by having a male copulatory organ (MCO) composed of an arcuate copulatory tube articulated to an eight-shaped accessory piece with terminal claw. The new species resembles Annulotrema pikei (Price, Peebles & Bamford, 1969) in having morphologically similar types of haptoral sclerites and MCO. As a result of the differential diagnosis made for A. besalis n. sp., new information on taxonomically important features of A. pikei is provided based on illustrations of the sclerotized parts of the holotype from Hydrocynus vittatus. The report of A. pikei on the gills of Hydrocynus forskahlii by Paperna in 1979 is shown to be erroneous. Annulotrema uncata n. sp. is similar to Annulotrema alestesimberi Paperna, 1973 in its possession of a coiled copulatory tube with about two and a half rings. Features distinguishing the new species include the sharply curved shaft of the ventral anchor, the base of the copulatory tube extending to a sock-like structure and a leech-shaped vagina. The necessity of emending the generic diagnosis of Annulotrema is briefly discussed. PMID:24972586

  6. Population Genetics as a Tool to Select Tsetse Control Strategies: Suppression or Eradication of Glossina palpalis gambiensis in the Niayes of Senegal

    PubMed Central

    Solano, Philippe; Kaba, Dramane; Ravel, Sophie; Dyer, Naomi A.; Sall, Baba; Vreysen, Marc J. B.; Seck, Momar T.; Darbyshir, Heather; Gardes, Laetitia; Donnelly, Martin J.; De Meeûs, Thierry; Bouyer, Jérémy

    2010-01-01

    Background The Government of Senegal has initiated the “Projet de lutte contre les glossines dans les Niayes” to remove the trypanosomosis problem from this area in a sustainable way. Due to past failures to sustainably eradicate Glossina palpalis gambiensis from the Niayes area, controversies remain as to the best strategy implement, i.e. “eradication” versus “suppression.” To inform this debate, we used population genetics to measure genetic differentiation between G. palpalis gambiensis from the Niayes and those from the southern tsetse belt (Missira). Methodology/Principal Findings Three different markers (microsatellite DNA, mitochondrial CO1 DNA, and geometric morphometrics of the wings) were used on 153 individuals and revealed that the G. p. gambiensis populations of the Niayes were genetically isolated from the nearest proximate known population of Missira. The genetic differentiation measured between these two areas (θ = 0.12 using microsatellites) was equivalent to a between-taxa differentiation. We also demonstrated that within the Niayes, the population from Dakar – Hann was isolated from the others and had probably experienced a bottleneck. Conclusion/Significance The information presented in this paper leads to the recommendation that an eradication strategy for the Niayes populations is advisable. This kind of study may be repeated in other habitats and for other tsetse species to (i) help decision on appropriate tsetse control strategies and (ii) find other possible discontinuities in tsetse distribution. PMID:20520795

  7. Impact of photoperiod manipulation on day/night changes in melatonin, sex steroids and vitellogenin plasma levels and spawning rhythms in Senegal sole, Solea senegalensis.

    PubMed

    Oliveira, Catarina; Mañanós, Evaristo; Ramos, Jesus; Sánchez-Vázquez, Francisco Javier

    2011-07-01

    Photoperiod and temperature are known as the main synchronizers of seasonal reproduction in fish. This paper studied the role of photoperiod on the synchronization of F1 Senegal sole reproduction rhythms. Fish were maintained under constant short-photoperiod (9L:15D) from the winter solstice onwards (experimental group) or under naturally-changing photoperiod (control group), and water temperature naturally oscillated in both groups. Blood samples were collected during the reproduction season at pre-spawning (March), spawning (April) and post-spawning (May) to determine the endocrine status. Spawning events and egg quality parameters were also monitored. The results revealed a significant increase in nocturnal melatonin concentration from March to May in the control group, while in the experimental group such seasonal change did not occur. As to plasma levels of vitellogenin, testosterone, estradiol and 11keto-testosterone, differences between groups were found mostly in March, while in April and May levels were often similar. Spawning was observed in both groups, although the experimental group started slightly earlier and also finished earlier than the control group, perhaps as a result of the increase in sex steroids and VTG observed at pre-spawning. Briefly, reproduction rhythms persisted in the absence of the natural lengthening of photoperiod, although photoperiod manipulation altered the seasonal modulation of melatonin, increased sex steroids and vitellogenin at pre-spawning, and slightly advanced the timing of spawning. PMID:21466857

  8. Stratified entomological sampling in preparation for an area-wide integrated pest management program: the example of Glossina palpalis gambiensis (Diptera: Glossinidae) in the Niayes of Senegal.

    PubMed

    Bouyer, Jérémy; Seck, Momar Talla; Sall, Baba; Ndiaye, Elhadji Youssou; Guerrini, Laure; Vreysen, Marc J B

    2010-07-01

    The riverine tsetse species Glossina palpalis gambiensis Vanderplank 1949 (Diptera: Glossinidae) inhabits riparian forests along river systems in West Africa. The government of Senegal has embarked on a project to eliminate this tsetse species, and African animal trypanosomoses, from the Niayes area using an area-wide integrated pest management approach. A stratified entomological sampling strategy was therefore developed using spatial analytical tools and mathematical modeling. A preliminary phytosociological census identified eight types of suitable habitat, which could be discriminated from LandSat 7 ETM+ satellite images and denominated wet areas. At the end of March 2009, 683 unbaited Vavoua traps had been deployed, and the observed infested area in the Niayes was 525 km2. In the remaining area, a mathematical model was used to assess the risk that flies were present despite a sequence of zero catches. The analysis showed that this risk was above 0.05 in 19% of this area that will be considered as infested during the control operations. The remote sensing analysis that identified the wet areas allowed a restriction of the area to be surveyed to 4% of the total surface area (7,150 km2), whereas the mathematical model provided an efficient method to improve the accuracy and the robustness of the sampling protocol. The final size of the control area will be decided based on the entomological collection data. This entomological sampling procedure might be used for other vector or pest control scenarios. PMID:20695269

  9. Management of uncomplicated malaria in children under 13 years of age at a district hospital in senegal: from official guidelines to usual practices

    PubMed Central

    2011-01-01

    Background To be effective, national malaria guidelines must be properly followed. This study evaluated nurses' practices in the management of uncomplicated malaria cases at a District Hospital. Its objective was to identify the reasons for discrepancies between official guidelines and usual practices. Methods This study took place at Oussouye hospital, south-western Senegal. Blood smears were available for biological diagnosis in patients aged more than five years while the Integrated Management of Childhood Illness recommended treating fevers presumptively in children under five. First line anti-malarial was Amodiaquine plus sulphadoxine-pyrimethamine (AQ+SP) bi-therapy. Hospital records of children under 13 years of age seen between 2004 and 2005 were reviewed. Results Among children treated with anti-malarials, 74% (2, 063/2, 789) received AQ+SP. However, only 22% (406/1, 879) of febrile children and 19% (429/2, 198) of children diagnosed with malaria got a blood smear. Moreover, an anti-malarial was prescribed for 80% (377/474) of children with a negative blood smear. Conclusions The transition from chloroquine to AQ+SP was well followed. Nonetheless, blood smear use was very low and many over-prescriptions were reported. Reasons for discrepancies between guidelines and practices can be classified in three main categories: ambiguous guidelines, health system's dysfunctions and nurses' own considerations. Aside from the strengthening of the public health system, in order to guarantee practices complying with guidelines, training content should be more adapted to nurses' own considerations. PMID:21958422

  10. A large outbreak of scombroid fish poisoning associated with eating yellowfin tuna (Thunnus albacares) at a military mass catering in Dakar, Senegal.

    PubMed

    Demoncheaux, J-P; Michel, R; Mazenot, C; Duflos, G; Iacini, C; de Laval, F; Delaval, F; Saware, E M; Renard, J-C

    2012-06-01

    On 26 November 2010, an outbreak of scombroid fish poisoning occurred in the French Armed Forces in Dakar, Senegal. This chemical intoxication, due to high histamine concentration in fish, is often mistaken for an allergic reaction. A case-control study was undertaken including the 71 cases and 78 randomly selected controls among lunch attendees. The usual symptoms for scombroid fish poisoning were observed in cases, i.e. flushing (85.9%), headache (83.1%), rapid/weak pulse (59.1%) and diarrhoea (47.9%). Symptoms occurred from within a few minutes to up to 3 h following the meal. Most patients quickly recovered with antihistamine and/or symptomatic treatment. Tuna was the only food item positively associated with illness (odds ratio 36.3, 95% confidence interval 6.3-210.0), with the risk of illness increasing with the quantity of fish consumed. No bacterial contamination was found in leftover food, but histamine concentration in tuna was found to be 4900 mg/kg, almost 50-fold higher than the concentration allowed by European regulations. This report is unique because of the large size of the case series - to our knowledge, the largest event of scombroid fish poisoning ever reported - and the chemical and bacteriological analyses results obtained on leftover food. PMID:21875451

  11. A ninety-day oral toxicity study of a new type of processed gum arabic, from Acacia tree (Acacia senegal) exudates, in F344 rats.

    PubMed

    Doi, Y; Ichihara, T; Hagiwara, A; Imai, N; Tamano, S; Orikoshi, H; Ogasawara, K; Sasaki, Y; Nakamura, M; Shirai, T

    2006-04-01

    This study was designed to evaluate and characterize any subchronic toxicity of a new type of gum arabic (SUPER GUM [Acacia(sen)SUPER GUM]), a naturally processed polysaccharide exudate from gum acacia trees (Acacia senegal), when administered to both sexes of F344 rats at dietary levels of 0 (control), 1.25%, 2.5%, and 5.0% (10 rats/sex/group). During the study, the treatment had no effects on clinical signs, survival, body weights, and food and water consumption, or on findings of urinalysis, ophthalmology, hematology, or blood biochemistry. Gross pathology and histopathology exhibited no differences of toxicological significance between control and treated rats. Increased relative cecum (filled) weights, evident in both sexes of 5.0% group and females of 1.25% and 2.5% groups, were considered to be a physiological adaptation. Thus, the results indicated the toxic level of SUPER GUM to be more than 5.0%, and the no observed adverse effect level (NOAEL) was concluded to be 5.0% (3,117 mg/kg body weights/day for males, and 3,296 mg/kg body weights/day for males) from the present study. PMID:16256256

  12. Migration statistics relevant for malaria transmission in Senegal derived from mobile phone data and used in an agent-based migration model.

    PubMed

    Tompkins, Adrian M; McCreesh, Nicky

    2016-01-01

    One year of mobile phone location data from Senegal is analysed to determine the characteristics of journeys that result in an overnight stay, and are thus relevant for malaria transmission. Defining the home location of each person as the place of most frequent calls, it is found that approximately 60% of people who spend nights away from home have regular destinations that are repeatedly visited, although only 10% have 3 or more regular destinations. The number of journeys involving overnight stays peaks at a distance of 50 km, although roughly half of such journeys exceed 100 km. Most visits only involve a stay of one or two nights away from home, with just 4% exceeding one week. A new agent-based migration model is introduced, based on a gravity model adapted to represent overnight journeys. Each agent makes journeys involving overnight stays to either regular or random locations, with journey and destination probabilities taken from the mobile phone dataset. Preliminary simulations show that the agent-based model can approximately reproduce the patterns of migration involving overnight stays. PMID:27063741

  13. Acetobacter senegalensis sp. nov., a thermotolerant acetic acid bacterium isolated in Senegal (sub-Saharan Africa) from mango fruit (Mangifera indica L.).

    PubMed

    Ndoye, Bassirou; Cleenwerck, Ilse; Engelbeen, Katrien; Dubois-Dauphin, Robin; Guiro, Amadou Tidiane; Van Trappen, Stefanie; Willems, Anne; Thonart, Phillipe

    2007-07-01

    A thermotolerant acetic acid bacterium, designated strain CWBI-B418(T), isolated in Senegal from mango fruit (Mangifera indica), was characterized in detail by means of genotypic and phenotypic methods. The novel strain was strictly aerobic and exhibited optimal growth on YGM medium at 35 degrees C. Cells were Gram-negative, motile and coccoid. The strain was assigned to the genus Acetobacter on the basis of 16S rRNA gene sequence analysis. DNA-DNA hybridization experiments with its phylogenetically closest relatives showed that strain CWBI-B418(T) represented a novel Acetobacter genospecies. The DNA G+C content of strain CWBI-B418(T) was 56.0 mol%. Phenotypic characteristics enabling the differentiation of strain CWBI-B418(T) from phylogenetically related Acetobacter species were: production of 2-keto-D-gluconic acid from D-glucose, but not 5-keto-D-gluconic acid, production of catalase but not oxidase, growth on yeast extract with 30 % d-glucose, growth with ammonium as sole nitrogen source with ethanol as carbon source, utilization of glycerol and ethanol but not maltose or methanol as carbon sources, and growth in the presence of 10 % ethanol. Based on the genotypic and phenotypic data presented, strain CWBI-B418(T) clearly represents a novel Acetobacter species, for which the name Acetobacter senegalensis sp. nov. is proposed. The type strain is CWBI-B418(T) (=LMG 23690(T)=DSM 18889(T)). PMID:17625197

  14. Brief communication: Reaction to fire by savanna chimpanzees (Pan troglodytes verus) at Fongoli, Senegal: Conceptualization of "fire behavior" and the case for a chimpanzee model.

    PubMed

    Pruetz, Jill D; LaDuke, Thomas C

    2010-04-01

    The use and control of fire are uniquely human traits thought to have come about fairly late in the evolution of our lineage, and they are hypothesized to correlate with an increase in intellectual complexity. Given the relatively sophisticated cognitive abilities yet small brain size of living apes compared to humans and even early hominins, observations of wild chimpanzees' reactions to naturally occurring fire can help inform hypotheses about the likely responses of early hominins to fire. We use data on the behavior of savanna chimpanzees (Pan troglodytes verus) at Fongoli, Senegal during two encounters with wildfires to illuminate the similarities between great apes and humans regarding their reaction to fire. Chimpanzees' close relatedness to our lineage makes them phylogenetically relevant to the study of hominid evolution, and the open, hot and dry environment at Fongoli, similar to the savanna mosaic thought to characterize much of hominid evolution, makes these apes ecologically important as a living primate model as well. Chimpanzees at Fongoli calmly monitor wildfires and change their behavior in anticipation of the fire's movement. The ability to conceptualize the "behavior" of fire may be a synapomorphic trait characterizing the human-chimpanzee clade. If the cognitive underpinnings of fire conceptualization are a primitive hominid trait, hypotheses concerning the origins of the control and use of fire may need revision. We argue that our findings exemplify the importance of using living chimpanzees as models for better understanding human evolution despite recently published suggestions to the contrary. PMID:20027607

  15. Description of a new species of Eimeria Schneider, 1875 (Apicomplexa: Eimeriidae) from the western Derby eland Taurotragus derbianus derbianus Gray (Artiodactyla: Bovidae) in Senegal.

    PubMed

    Máca, Ondřej

    2012-06-01

    Examination of faecal samples from semi-captive western Derby elands Taurotragus derbianus derbianus Gray, in the Bandia and Fathala Reserves of Senegal, revealed the presence of oöcysts of the genus Eimeria Schneider, 1875 that we considered to represent a new species, Eimeria derbiani n. sp. The new species possesses nearly ellipsoidal oöcysts (length/width ratio 1.3) with a bi-layered wall and an average size of 27.6 × 21.5 μm. E. derbiani possesses a micropyle covered by a micropylar cap and ovoidal, single-layered sporocysts with an average size of 14.9 × 7.7 μm, each with a Stieda body. Sporozoites of E. derbiani possess a large refractile body and a nucleus. Sporulation lasted for 2 days at 23°C. The new species is differentiated from the two species parasitising Taurotragus oryx Pallas, E. canna Triffitt, 1924 and E. triffittae Yakimoff, 1934. PMID:22581248

  16. Admittance of Au/1,4-benzenedithiol/Au single-molecule junctions

    NASA Astrophysics Data System (ADS)

    Yamauchi, Kazumasa; Kurokawa, Shu; Sakai, Akira

    2012-12-01

    Employing the admittance formula for double-barrier junctions [Fu and Dudley, Phys. Rev. Lett. 70, 65 (1993)], we have estimated an ac susceptance (imaginary part of admittance) of Au/1,4-benzenedithiol/Au single-molecule junctions from their current-voltage characteristics. In the MHz regime, we find that the junction susceptance shows a very small (˜0.1 aF) capacitive component that can be entirely masked by a larger electrode capacitance. Direct ac signal transmission measurements up to 1 GHz reveal no molecular signals and confirm the smallness of the molecular capacitance in the MHz regime.

  17. Net charge fluctuations in Au + Au interactions at sqrt[s(NN)]=130 GeV.

    PubMed

    Adcox, K; Adler, S S; Ajitanand, N N; Akiba, Y; Alexander, J; Aphecetche, L; Arai, Y; Aronson, S H; Averbeck, R; Awes, T C; Barish, K N; Barnes, P D; Barrette, J; Bassalleck, B; Bathe, S; Baublis, V; Bazilevsky, A; Belikov, S; Bellaiche, F G; Belyaev, S T; Bennett, M J; Berdnikov, Y; Botelho, S; Brooks, M L; Brown, D S; Bruner, N; Bucher, D; Buesching, H; Bumazhnov, V; Bunce, G; Burward-Hoy, J; Butsyk, S; Carey, T A; Chand, P; Chang, J; Chang, W C; Chavez, L L; Chernichenko, S; Chi, C Y; Chiba, J; Chiu, M; Choudhury, R K; Christ, T; Chujo, T; Chung, M S; Chung, P; Cianciolo, V; Cole, B A; D'Enterria, D G; David, G; Delagrange, H; Denisov, A; Deshpande, A; Desmond, E J; Dietzsch, O; Dinesh, B V; Drees, A; Durum, A; Dutta, D; Ebisu, K; Efremenko, Y V; El Chenawi, K; En'yo, H; Esumi, S; Ewell, L; Ferdousi, T; Fields, D E; Fokin, S L; Fraenkel, Z; Franz, A; Frawley, A D; Fung, S-Y; Garpman, S; Ghosh, T K; Glenn, A; Godoi, A L; Goto, Y; Greene, S V; Grosse Perdekamp, M; Gupta, S K; Guryn, W; Gustafsson, H-A; Haggerty, J S; Hamagaki, H; Hansen, A G; Hara, H; Hartouni, E P; Hayano, R; Hayashi, N; He, X; Hemmick, T K; Heuser, J M; Hibino, M; Hill, J C; Ho, D S; Homma, K; Hong, B; Hoover, A; Ichihara, T; Imai, K; Ippolitov, M S; Ishihara, M; Jacak, B V; Jang, W Y; Jia, J; Johnson, B M; Johnson, S C; Joo, K S; Kametani, S; Kang, J H; Kann, M; Kapoor, S S; Kelly, S; Khachaturov, B; Khanzadeev, A; Kikuchi, J; Kim, D J; Kim, H J; Kim, S Y; Kim, Y G; Kinnison, W W; Kistenev, E; Kiyomichi, A; Klein-Boesing, C; Klinksiek, S; Kochenda, L; Kochetkov, V; Koehler, D; Kohama, T; Kotchetkov, D; Kozlov, A; Kroon, P J; Kurita, K; Kweon, M J; Kwon, Y; Kyle, G S; Lacey, R; Lajoie, J G; Lauret, J; Lebedev, A; Lee, D M; Leitch, M J; Li, X H; Li, Z; Lim, D J; Liu, M X; Liu, X; Liu, Z; Maguire, C F; Mahon, J; Makdisi, Y I; Manko, V I; Mao, Y; Mark, S K; Markacs, S; Martinez, G; Marx, M D; Masaike, A; Matathias, F; Matsumoto, T; McGaughey, P L; Melnikov, E; Merschmeyer, M; Messer, F; Messer, M; Miake, Y; Miller, T E; Milov, A; Mioduszewski, S; Mischke, R E; Mishra, G C; Mitchell, J T; Mohanty, A K; Morrison, D P; Moss, J M; Mühlbacher, F; Muniruzzaman, M; Murata, J; Nagamiya, S; Nagasaka, Y; Nagle, J L; Nakada, Y; Nandi, B K; Newby, J; Nikkinen, L; Nilsson, P; Nishimura, S; Nyanin, A S; Nystrand, J; O'Brien, E; Ogilvie, C A; Ohnishi, H; Ojha, I D; Ono, M; Onuchin, V; Oskarsson, A; Osterman, L; Otterlund, I; Oyama, K; Paffrath, L; Palounek, A P T; Pantuev, V S; Papavassiliou, V; Pate, S F; Peitzmann, T; Petridis, A N; Pinkenburg, C; Pisani, R P; Pitukhin, P; Plasil, F; Pollack, M; Pope, K; Purschke, M L; Ravinovich, I; Read, K F; Reygers, K; Riabov, V; Riabov, Y; Rosati, M; Rose, A A; Ryu, S S; Saito, N; Sakaguchi, A; Sakaguchi, T; Sako, H; Sakuma, T; Samsonov, V; Sangster, T C; Santo, R; Sato, H D; Sato, S; Sawada, S; Schlei, B R; Schutz, Y; Semenov, V; Seto, R; Shea, T K; Shein, I; Shibata, T-A; Shigaki, K; Shiina, T; Shin, Y H; Sibiriak, I G; Silvermyr, D; Sim, K S; Simon-Gillo, J; Singh, C P; Singh, V; Sivertz, M; Soldatov, A; Soltz, R A; Sorensen, S; Stankus, P W; Starinsky, N; Steinberg, P; Stenlund, E; Ster, A; Stoll, S P; Sugioka, M; Sugitate, T; Sullivan, J P; Sumi, Y; Sun, Z; Suzuki, M; Takagui, E M; Taketani, A; Tamai, M; Tanaka, K H; Tanaka, Y; Taniguchi, E; Tannenbaum, M J; Thomas, J; Thomas, J H; Thomas, T L; Tian, W; Tojo, J; Torii, H; Towell, R S; Tserruya, I; Tsuruoka, H; Tsvetkov, A A; Tuli, S K; Tydesjö, H; Tyurin, N; Ushiroda, T; van Hecke, H W; Velissaris, C; Velkovska, J; Velkovsky, M; Vinogradov, A A; Volkov, M A; Vorobyov, A; Vznuzdaev, E; Wang, H; Watanabe, Y; White, S N; Witzig, C; Wohn, F K; Woody, C L; Xie, W; Yagi, K; Yokkaichi, S; Young, G R; Yushmanov, I E; Zajc, W A; Zhang, Z; Zhou, S

    2002-08-19

    Data from Au + Au interactions at sqrt[s(NN)]=130 GeV, obtained with the PHENIX detector at the Relativistic Heavy-Ion Collider, are used to investigate local net charge fluctuations among particles produced near midrapidity. According to recent suggestions, such fluctuations may carry information from the quark-gluon plasma. This analysis shows that the fluctuations are dominated by a stochastic distribution of particles, but are also sensitive to other effects, like global charge conservation and resonance decays. PMID:12190459

  18. Domain wall dynamics in a spin-reorientation transition system Au/Co/Au

    SciTech Connect

    Roy, Sujoy; Seu, Keoki; Turner, Joshua J.; Park, Sungkyun; Kevan, Steve; Falco, Charles M.

    2009-05-14

    We report measurements of domain wall dynamics in an ultrathin Au/Co/Au system that exhibits a spin reorientation phase transition as a function of temperature.The domain walls exhibit cooperative motion throughout the temperature range of 150 - 300 K. The decay times were found to exhibit a maximum at the transition temperature. The slowdown has been explained as due to formation of a double well in the energy landscape by the different competing interactions. Our results show that the complex, slow dynamics can provide a more fundamental understanding of magnetic phase transitions.

  19. Measuring away-side jet modifications in Au+Au collisions at RHIC

    NASA Astrophysics Data System (ADS)

    Jiang, Kun; STAR Collaboration

    2015-08-01

    We report measurements of jet correlations in Au+Au collisions at = 200 GeV by the STAR experiment. In this analysis we devise a novel method to subtract flow background using data itself. The correlation width is studied as a function of centrality and associated particle pTT. The width is found to increase with centrality at modest to high associated particle pTT. The increase can arise from jet modification by medium and/or event averaging of away-side jets deflected by medium flow. The discrimination of the physics mechanisms requires further study by three-particle correlations.

  20. Energy Dependence of Particle Multiplicities in Central Au+Au Collisions

    NASA Astrophysics Data System (ADS)

    Back, B. B.; Baker, M. D.; Barton, D. S.; Betts, R. R.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Corbo, J.; Decowski, M. P.; Garcia, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Henderson, C.; Hicks, D.; Hofman, D.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Michałowski, J.; Mignerey, A.; Mülmenstädt, J.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Rafelski, M.; Rbeiz, M.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steadman, S. G.; Steinberg, P.; Stephans, G. S.; Stodulski, M.; Sukhanov, A.; Tang, J.-L.; Teng, R.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wadsworth, B.; Wolfs, F. L.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.

    2002-01-01

    We present the first measurement of the pseudorapidity density of primary charged particles in Au+Au collisions at (sNN) = 200 GeV. For the 6% most central collisions, we obtain dNch/dη\\|\\|η\\|<1 = 650+/-35(syst). Compared to collisions at (sNN) = 130 GeV, the highest energy studied previously, an increase by a factor of 1.14+/-0.05 at 90% confidence level, is found. The energy dependence of the pseudorapidity density is discussed in comparison with data from proton-induced collisions and theoretical predictions.

  1. Beam Energy Scan a Case for the Chiral Magnetic Effect in Au-Au Collisions

    SciTech Connect

    Longacre, R.

    2014-01-05

    The Chiral Magnetic Effect (CME) is predicted for Au-Au collisions at RHIC. However, many backgrounds can give signals that make the measurement hard to interpret. The STAR experiment has made measurements at different collisions energy ranging from √(sNN)=7.7 GeV to 62.4 GeV. In the analysis that is presented we show that the CME turns on with energy and is not present in central collisions where the induced magnetic is small.

  2. Two-Particle Interferometry of 200 GeV Au+Au Collisions at PHENIX

    SciTech Connect

    Heffner, M

    2004-04-19

    The PHENIX experiment has measured pion-pion, kaon-kaon, and proton-proton correlations in Au+Au collisions at {radical}S{sub NN} = 200GeV. The correlations are fit to extract radii using both the Bowler Coulomb correction and full calculation of the two-particle wave function. The resulting radii are similar for all three species and decrease with increasing k{sub t} as expected for collective flow. The R{sub out} and R{sub side} radii are approximately equal indicating a short emission duration.

  3. Onset of nuclear vaporization in [sup 197]Au+[sup 197]Au collisions

    SciTech Connect

    Tsang, M.B.; Hsi, W.C.; Lynch, W.G.; Bowman, D.R.; Gelbke, C.K.; Lisa, M.A.; Peaslee, G.F. ); Kunde, G.J.; Begemann-Blaich, M.L.; Hofmann, T.; Hubele, J.; Kempter, J.; Kreutz, P.; Kunze, W.D.; Lindenstruth, V.; Lynen, U.; Mang, M.; Mueller, W.F.J.; Neumann, M.; Ocker, B.; Ogilvie, C.A.; Pochodzalla, J.; Rosenberger, F.; Sann, H.; Schuettauf, A.; Serfling, V.; Stroth, J.; Trautmann, W.; Tucholski, A.; Woerner, A.; Zude, E.; Zwieglinski, B. ); Aiello, S.; Imme, G.; Pappalardo, V.; Raciti, G. ); Charity, R.J.; Sobotka, L.G. ); Iori, I.; Moroni, A.; Scardoni, R.; Ferr

    1993-09-06

    Multifragmentation has been measured for [sup 197]Au+[sup 197]Au collisions at [ital E]/[ital A]=100, 250, and 400 MeV. The mean fragment multiplicity increases monotonically with the charged particle multiplicity at [ital E]/[ital A]=100 MeV, but decreases for central collisions with incident energy, consistent with the onset of nuclear vaporization. Molecular dynamics calculations follow some trends but underpredict the observed fragment multiplicities. Including the statistical decay of excited residues improves the agreement for peripheral collisions but worsens it for central collisions.

  4. Relativistic multireference many-body perturbation theory calculations on Au64+ - Au69+ ions

    SciTech Connect

    Vilkas, M J; Ishikawa, Y; Trabert, E

    2006-03-31

    Many-body perturbation theory (MBPT) calculations are an adequate tool for the description of the structure of highly charged multi-electron ions and for the analysis of their spectra. They demonstrate this by way of a re-investigation of n=3, {Delta}n=0 transitions in the EUV spectra of Na-, Mg-, Al-like, and Si-like ions of Au that have been obtained previously by heavy-ion accelerator based beam-foil spectroscopy. They discuss the evidence and propose several revisions on the basis of the multi-reference many-body perturbation theory calculations of Ne- through P-like ions of Au.

  5. Initial-state geometry and fluctuations in Au + Au, Cu + Au, and U + U collisions at energies available at the BNL Relativistic Heavy Ion Collider

    NASA Astrophysics Data System (ADS)

    Schenke, Björn; Tribedy, Prithwish; Venugopalan, Raju

    2014-06-01

    We study within the IP-Glasma and two-component MC-Glauber models the effects of initial-state geometry and fluctuations on multiplicities and eccentricities for several collision species at the Relativistic Heavy Ion Collider (RHIC). These include copper-gold (Cu + Au), gold-gold (Au + Au), and uranium-uranium (U + U) collisions. The multiplicity densities per participant pair are very similar in all systems studied. Ellipticities vary strongly between collision systems, most significantly for central collisions, while fluctuation driven odd moments vary little between systems. Event-by-event distributions of eccentricities in mid-central collisions are wider in Cu + Au relative to Au + Au and U + U systems. An anticorrelation between multiplicity and eccentricity is observed in ultracentral U + U collisions which is weaker in the IP-Glasma model than the two-component MC-Glauber model. In ultracentral Au + Au collisions the two models predict opposite signs for the slope of this correlation. Measurements of elliptic flow as a function of multiplicity in such central events can therefore be used to discriminate between models with qualitatively different particle production mechanisms.

  6. Bridging gold in electron-deficient Al2Au(n)(0/-) and BAlAu(n)(0/-) (n = 1-3) clusters.

    PubMed

    Yao, Wen-Zhi; Liu, Bing-Tao; Lu, Zhang-Hui; Li, Si-Dian

    2013-06-20

    The geometrical and electronic structures of the electron-deficient dialuminum aurides Al2Aun(0/-) and hybrid boron-aluminum aurides BAlAun(0/-) (n = 1-3) are systematically investigated based on the density and wave function theories. Ab initio theoretical evidence strongly suggests that bridging gold atoms exist in the ground states of C2v Al2Au(-) ((3)B1), C2v Al2Au ((2)B1), C2v Al2Au2(-) ((2)A1), C2v Al2Au2 ((1)A1), Cs Al2Au3(-) ((1)A'), and D3h Al2Au3 ((2)A1), which prove to possess an Al-Au-Al τ bond. For BAlAun(0/-) (n = 1-3) mixed clusters, bridging B-Au-Al units only exist in Cs BAlAu3(-) ((1)A') and Cs BAlAu3 ((2)A'), whereas Cs BAlAu(-) ((3)A''), Cs BAlAu ((2)A''), Cs BAlAu2(-) ((2)A'), and Cs BAlAu2 ((1)A') do not possess a bridging gold, as demonstrated by the fact that B-Al and B-Au exhibit significantly stronger electronic interaction than Al-Au in the same clusters. Orbital analyses indicate that Au 6s contributes approximately 98%-99% to the Au-based orbital in these Al-Au-Al/B-Au-Al interactions, whereas Au 5d contributes 1%-2%. The adiabatic and vertical detachment energies of Al2Aun(-) (n = 1-3) are calculated to facilitate future experimental characterizations. The results obtained in this work establish an interesting τ bonding model (Al-Au-Al/B-Au-Al) for electron-deficient systems in which Au 6s plays a major factor. PMID:23718624

  7. Cu-Au, Ag-Au, Cu-Ag, and Ni-Au intermetallics: First-principles study of temperature-composition phase diagrams and structures

    NASA Astrophysics Data System (ADS)

    Ozoliņš, V.; Wolverton, C.; Zunger, Alex

    1998-03-01

    The classic metallurgical systems-noble-metal alloys-that have formed the benchmark for various alloy theories are revisited. First-principles fully relaxed general-potential linearized augmented plane-wave (LAPW) total energies of a few ordered structures are used as input to a mixed-space cluster expansion calculation to study the phase stability, thermodynamic properties, and bond lengths in Cu-Au, Ag-Au, Cu-Ag, and Ni-Au alloys. (i) Our theoretical calculations correctly reproduce the tendencies of Ag-Au and Cu-Au to form compounds and Ni-Au and Cu-Ag to phase separate at T=0 K. (ii) Of all possible structures, Cu3Au (L12) and CuAu (L10) are found to be the most stable low-temperature phases of Cu1-xAux with transition temperatures of 530 K and 660 K, respectively, compared to the experimental values 663 K and ~670 K. The significant improvement over previous first-principles studies is attributed to the more accurate treatment of atomic relaxations in the present work. (iii) LAPW formation enthalpies demonstrate that L12, the commonly assumed stable phase of CuAu3, is not the ground state for Au-rich alloys, but rather that ordered (100) superlattices are stabilized. (iv) We extract the nonconfigurational (e.g., vibrational) entropies of formation and obtain large values for the size-mismatched systems: 0.48 kB/atom in Ni0.5Au0.5 (T=1100 K), 0.37 kB/atom in Cu0.141Ag0.859 (T=1052 K), and 0.16 kB/atom in Cu0.5Au0.5 (T=800 K). (v) Using 8 atom/cell special quasirandom structures we study the bond lengths in disordered Cu-Au and Ni-Au alloys and obtain good qualitative agreement with recent extended x-ray-absorption fine-structure measurements.

  8. Electrostatic assembles and optical properties of Au CdTe QDs and Ag/Au CdTe QDs

    NASA Astrophysics Data System (ADS)

    Yang, Dongzhi; Wang, Wenxing; Chen, Qifan; Huang, Yuping; Xu, Shukun

    2008-09-01

    Au-CdTe and Ag/Au-CdTe assembles were firstly investigated through the static interaction between positively charged cysteamine-stabilized CdTe quantum dots (QDs) and negatively charged Au or core/shell Ag/Au nano-particles (NCs). The CdTe QDs synthesized in aqueous solution were capped with cysteamine which endowed them positive charges on the surface. Both Au and Ag/Au NCs were prepared through reducing precursors with gallic acid obtained from the hydrolysis of natural plant poly-phenols and favored negative charges on the surface of NCs. The fluorescence spectra of CdTe QDs exhibited strong quenching with the increase of added Au or Ag/Au NCs. Railey resonance scattering spectra of Au or Ag/Au NCs increased firstly and decreased latter with the concentration of CdTe QDs, accompanied with the solution color changing from red to purple and colorless at last. Experimental results on the effects of gallic acid, chloroauric acid tetrahydrate and other reagents demonstrated the static interaction occurred between QDs and NCs. This finding reveals the possibilities to design and control optical process and electromagnetic coupling in hybrid structures.

  9. Au/Pd core-shell nanoparticles with varied hollow Au cores for enhanced formic acid oxidation

    NASA Astrophysics Data System (ADS)

    Hsu, Chiajen; Huang, Chienwen; Hao, Yaowu; Liu, Fuqiang

    2013-03-01

    A facile method has been developed to synthesize Au/Pd core-shell nanoparticles via galvanic replacement of Cu by Pd on hollow Au nanospheres. The unique nanoparticles were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, ultraviolet-visible spectroscopy, and electrochemical measurements. When the concentration of the Au solution was decreased, grain size of the polycrystalline hollow Au nanospheres was reduced, and the structures became highly porous. After the Pd shell formed on these Au nanospheres, the morphology and structure of the Au/Pd nanoparticles varied and hence significantly affected the catalytic properties. The Au/Pd nanoparticles synthesized with reduced Au concentrations showed higher formic acid oxidation activity (0.93 mA cm-2 at 0.3 V) than the commercial Pd black (0.85 mA cm-2 at 0.3 V), suggesting a promising candidate as fuel cell catalysts. In addition, the Au/Pd nanoparticles displayed lower CO-stripping potential, improved stability, and higher durability compared to the Pd black due to their unique core-shell structures tuned by Au core morphologies.

  10. Au/Pd core-shell nanoparticles with varied hollow Au cores for enhanced formic acid oxidation

    PubMed Central

    2013-01-01

    A facile method has been developed to synthesize Au/Pd core-shell nanoparticles via galvanic replacement of Cu by Pd on hollow Au nanospheres. The unique nanoparticles were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, ultraviolet–visible spectroscopy, and electrochemical measurements. When the concentration of the Au solution was decreased, grain size of the polycrystalline hollow Au nanospheres was reduced, and the structures became highly porous. After the Pd shell formed on these Au nanospheres, the morphology and structure of the Au/Pd nanoparticles varied and hence significantly affected the catalytic properties. The Au/Pd nanoparticles synthesized with reduced Au concentrations showed higher formic acid oxidation activity (0.93 mA cm-2 at 0.3 V) than the commercial Pd black (0.85 mA cm-2 at 0.3 V), suggesting a promising candidate as fuel cell catalysts. In addition, the Au/Pd nanoparticles displayed lower CO-stripping potential, improved stability, and higher durability compared to the Pd black due to their unique core-shell structures tuned by Au core morphologies. PMID:23452438

  11. Lateral spreading of Au contacts on InP

    NASA Technical Reports Server (NTRS)

    Fatemi, Navid S.; Weizer, Victor G.

    1990-01-01

    The contact spreading phenomenon observed when small area Au contacts on InP are annealed at temperatures above about 400 C was investigated. It was found that the rapid lateral expansion of the contact metallization which consumes large quantities of InP during growth is closely related to the third stage in the series of solid state reactions that occur between InP and Au, i.e., to the Au3In-to-Au9In4 transition. Detailed descriptions are presented of both the spreading process and the Au3In-to-Au9In4 transition along with arguments that the two processes are manifestations of the same basic phenomenon.

  12. Structural and electronic properties of AuIr nanoalloys

    NASA Astrophysics Data System (ADS)

    Jiménez-Díaz, Laura M.; Pérez, Luis A.

    2013-01-01

    The lowest-energy structures of binary (AuIr) n , (AuIr3) s , and (Au3Ir) s clusters, with n = 2-20, and s = 5, modeled by the many-body Gupta potential, were obtained by using a genetic-symbiotic algorithm. These structures were further relaxed within the density functional theory to obtain the most stable structures for each composition. Segregation is observed in all the AuIr clusters, where the Ir atoms occupy the cluster core and the Au atoms are situated on the cluster surface. On the other hand, there is experimental evidence that the (AuIr) n nanoalloys could have an enhanced catalytic activity for CO oxidation. In order to study this phenomenon, we also performed first-principles density functional calculations of the CO and O2 adsorption on these bimetallic nanoclusters, considering three different compositions and a fixed cluster size of 20 atoms.

  13. Atomic and molecular adsorption on Au(111)

    SciTech Connect

    Santiago-Rodríguez, Yohaselly; Herron, Jeffrey A.; Curet-Arana, María C.; Mavrikakis, Manos

    2014-09-01

    Periodic self-consistent density functional theory (DFT-GGA) calculations were used to study the adsorption of several atomic species, molecular species and molecular fragments on the Au(111) surface with a coverage of 1/4 monolayer (ML). Binding geometries, binding energies, and diffusion barriers were calculated for 27 species. Furthermore, we calculated the surface deformation energy associated with the binding events. The binding strength for all the analyzed species can be ordered as follows: NH3 < NO < CO < CH3 < HCO < NH2 < COOH < OH < HCOO < CNH2 < H < N < NH < NOH < COH < Cl,< HCO3 < CH2 < CN b HNO < O < F < S < C < CH. Although the atomic species preferred to bind at the three-fold fcc site, no tendency was observed in site preference for the molecular species and fragments. The intramolecular and adsorbate-surface vibrational frequencies were calculated for all the adsorbates on their most energetically stable adsorption site. Most of the theoretical binding energies and frequencies agreed with experimental values reported in the literature. In general, the values obtained with the PW91 functional are more accurate than RPBE in reproducing these experimental binding energies. The energies of the adsorbed species were used to calculate the thermochemical potential energy surfaces for decomposition of CO, NO, N2, NH3 and CH4, oxidation of CO, and hydrogenation of CO, CO2 and NO, giving insight into the thermochemistry of these reactions on gold nanoparticles. These potential energy surfaces demonstrated that: the decomposition of species is not energetically favorable on Au(111); the desorption of NH3, NO and CO are more favorable than their decomposition; the oxidation of CO and hydrogenation of CO and NO on Au(111) to form HCO and HNO, respectively, are also thermodynamically favorable.

  14. Photosynthetic electron transport system promotes synthesis of Au-nanoparticles.

    PubMed

    Shabnam, Nisha; Pardha-Saradhi, P

    2013-01-01

    In this communication, a novel, green, efficient and economically viable light mediated protocol for generation of Au-nanoparticles using most vital organelle, chloroplasts, of the plant system is portrayed. Thylakoids/chloroplasts isolated from Potamogeton nodosus (an aquatic plant) and Spinacia oleracea (a terrestrial plant) turned Au³⁺ solutions purple in presence of light of 600 µmol m⁻² s⁻¹ photon flux density (PFD) and the purple coloration intensified with time. UV-Vis spectra of these purple colored solutions showed absorption peak at ∼545 nm which is known to arise due to surface plasmon oscillations specific to Au-nanoparticles. However, thylakoids/chloroplasts did not alter color of Au³⁺ solutions in dark. These results clearly demonstrated that photosynthetic electron transport can reduce Au³⁺ to Au⁰ which nucleate to form Au-nanoparticles in presence of light. Transmission electron microscopic studies revealed that Au-nanoparticles generated by light driven photosynthetic electron transport system of thylakoids/chloroplasts were in range of 5-20 nm. Selected area electron diffraction and powder X-ray diffraction indicated crystalline nature of these nanoparticles. Energy dispersive X-ray confirmed that these nanoparticles were composed of Au. To confirm the potential of light driven photosynthetic electron transport in generation of Au-nanoparticles, thylakoids/chloroplasts were tested for their efficacy to generate Au-nanoparticles in presence of light of PFD ranging from 60 to 600 µmol m⁻² s⁻¹. The capacity of thylakoids/chloroplasts to generate Au-nanoparticles increased remarkably with increase in PFD, which further clearly demonstrated potential of light driven photosynthetic electron transport in reduction of Au³⁺ to Au⁰ to form nanoparticles. The light driven donation of electrons to metal ions by thylakoids/chloroplasts can be exploited for large scale production of nanoparticles. PMID:23976990

  15. Systematic studies of the centrality dependence of soft photon production in Au + Au collision with PHENIX

    NASA Astrophysics Data System (ADS)

    Bannier, Benjamin

    2014-11-01

    Since the earliest days of Heavy Ion Physics thermal soft photon radiation emitted during the reaction had been theorized as a smoking gun signal for formation of a quark-gluon plasma and as a tool to characterize its properties. In recent years the existence of excess photon radiation in heavy ion collisions over the expectation from initial hard interactions has been confirmed at both RHIC and LHC energies by PHENIX and ALICE respectively. There the radiation has been found to exhibit elliptic flow v2 well above what can currently be reconciled with a picture of early emission from a plasma phase. During the 2007 and 2010 Au + Au runs PHENIX has measured a high purity sample of soft photons down to pT > 0.4 GeV / c using an external conversion method. We present recent systematic studies by PHENIX from that sample on the centrality dependence of the soft photon yield, and elliptic and triangular flow v2 and v3 in Au + Au collisions which fill in the experimental picture and enable discrimination of competing soft photon production scenarios.

  16. Photoionization of Au+ ions and developments in the synthesis of the metallofullerene Au@C60

    NASA Astrophysics Data System (ADS)

    Bogolub, Kyren; Macaluso, David; Mueller, Allison; Johnson, Andrea; Müller, Alfred; Schippers, Stefan; Hellhund, Jonas; Borovik, Alexander; Anders, Andre; Aguilar, Alex; Kilcoyne, A. L. David

    2014-05-01

    Single photoionization of Au+ ions was investigated via the merged-beams technique at AMO Beamline 10.0.1.2 of the Advanced Light Source at Lawrence Berkeley National Laboratory. The relative single photoionization yield was measured as a function of photon energy in the 45 eV to 120 eV energy range. These measurements were made in preparation for future photoionization studies of the endohedral metallofullerene Au@C60, the production of which was also investigated. In proof-of-principle measurements a mass-resolved beam of Au@C60+was produced with a primary ion beam current in the single picoamp range without optimization of the ion source or synthesis parameters. Plans are presented for improved metallofullere production yield to be used in photoionization measurements of the endohedral fullerene ions in conjunction with the continuing study of pure Au. We would like to acknowledge the generous sharing of equipment vital to this work by Andre Anders, the Plasma Applications group leader at the Advanced Light Source, LBNL.

  17. Preparations for p-Au run in 2015

    SciTech Connect

    Liu, C.

    2014-12-31

    The p-Au particle collision is a unique category of collision runs. This is resulted from the different charge mass ratio of the proton and fully stripped Au ion (1 vs.79/197). The p-Au run requires a special acceleration ramp, and movement of a number of beam components as required by the beam trajectories. The DX magnets will be moved for the first time in the history of RHIC. In this note, the planning and preparations for p-Au run will be presented.

  18. An Exploration of Catalytic Chemistry on Au/Ni(111)

    SciTech Connect

    Sylvia T. Ceyer

    2011-12-09

    This project explored the catalytic oxidation chemistry that can be effected on a Au/Ni(111) surface alloy. A Au/Ni(111) surface alloy is a Ni(111) surface on which less than 60% of the Ni atoms are replaced at random positions by Au atoms. The alloy is produced by vapor deposition of a small amount of Au onto Ni single crystals. The Au atoms do not result in an epitaxial Au overlayer or in the condensation of the Au into droplets. Instead, Au atoms displace and then replace Ni atoms on a Ni(111) surface, even though Au is immiscible in bulk Ni. The two dimensional structure of the clean Ni surface is preserved. This alloy is found to stabilize an adsorbed peroxo-like O2 species that is shown to be the critical reactant in the low temperature catalytic oxidation of CO and that is suspected to be the critical reactant in other oxidation reactions. This investigation revealed a new, practically important catalyst for CO oxidation that has since been patented.

  19. Heatless synthesis of well dispersible Au nanoparticles using pectin biopolymer.

    PubMed

    Ahmed, Hanan B; Zahran, M K; Emam, Hossam E

    2016-10-01

    Due to its potency to utilize in enormous applications, preparation of nanogold is of interest. Moreover, getting of highly dispersed nanogold with small size is extremely needful in specific fields. Herein, Au nanocolloid was prepared using alkali catalyzed pectin biopolymer. Pectin was concurrently used as reductant for Au ions and stabilizer for the produced Au nanoparticles (AuNPs). Reducing sugars were evaluated in the colloidal solution reflecting the role alkali in catalytic degradation of pectin to produce much powerful reducing moieties. The obtained Au nanocolloid was monitored via changing in color, UV-visible spectral and transmission electron microscopy. Using of NaOH as strong alkali achieving rapid rate of degradation reaction, resulted in 0.45g/L reducing sugars from 0.2g/L pectin which produced AuNPs with mean size of 6.5nm. In case of Na2CO3 which attained slow degradation rate led to, slightly low reducing sugar content (0.41g/L), fabricated comparatively size of AuNPs (7.5nm). In both cases, well distributed AuNPs was obtained with suitable stabilization up to 5 months and Na2CO3 exhibited higher stability. The current successful method used to produce small sized AuNPs with high dispersion is an innovative, one-step, easily, costless, energy saving and eco-friendly method. PMID:27212212

  20. Local anodic oxidation patterning of Au deposited Si surfaces.

    PubMed

    Vijaykumar, T; Kulkarni, G U

    2009-09-01

    Nanopatterning of Si(100) surfaces deposited with Au films from physical and chemical methods, has been carried out using a AFM set up mounted with a conducting tip. At a tip bias of -12 V, the LAO patterns drawn on various Au/SiOx surfaces have been compared with those on bare Si. The height of the oxide patterns is several times higher in the case of Au covered Si surfaces compared to patterns on bare Si surface. The enhancement in LAO is related to the catalytic activity of Au nanoparticulates at SiOx interface. PMID:19928226

  1. Prolonged reorganization of thiol-capped Au nanoparticles layered structures

    NASA Astrophysics Data System (ADS)

    Kundu, Sarathi; Das, Kaushik; Konovalov, Oleg

    2013-09-01

    Prolonged reorganization behaviour of mono-, di-, tri- and multi-layer films of Au nanoparticles prepared by Langmuir-Blodgett method on hydrophobic Si(001) substrates have been studied by using X-ray scattering techniques. Out-of-plane study shows that although at the initial stage the reorganization occurs through the compaction of the films keeping the layered structure unchanged but finally all layered structures modify to monolayer structure. Due to this reorganization the Au density increases within the nanometer thick films. In-plane study shows that inside the reorganized films Au nanoparticles are distributed randomly and the particle size modifies as the metallic core of Au nanoparticles coalesces.

  2. Layer growth in Au-Pb/In solder joints

    SciTech Connect

    Yost, F.G.; Ganyard, F.P.; Karnowsky, M.M.

    1986-01-01

    The solid state reaction between a Pb-In solder alloy and thin film Au has been investigated at ten aging temperatures ranging from 70 to 170/sup 0/C. Also, bulk Au-solder samples were aged at 150/sup 0/C for metallographic analysis. No significant difference was found between the aging behavior of thin and bulk Au specimens. A thin single phase layer of Au/sub 9/In/sub 4/ was found adjacent to Au while a thick two-phase layer of AuIn/sub 2/ and Pb was found between Au/sub 9/In/sub 4/ and solder. The Pb phase was shown to have considerable mobility and able to ripen at room temperature. Peculiar planar interface instabilities and voids in the Au-Au/sub 9/In/sub 4/ interface were found. The total layer thickness was found to vary linearly with aging time, indicating an interface-controlled reaction. An activation energy of 14,000 calories per mole was found by regression analysis of the kinetic data.

  3. Do Methanethiol Adsorbates on the Au(111) Surface Dissociate?

    NASA Astrophysics Data System (ADS)

    Zhou, Jian-Ge; Hagelberg, Frank

    2006-07-01

    The interaction of methanethiol molecules CH3SH with the Au(111) surface is investigated, and it is found for the first time that the S-H bond remains intact when the methanethiol molecules are adsorbed on the regular Au(111) surface. However, it breaks if defects are present in the Au(111) surface. At low coverage, the fcc region is favored for S atom adsorption, but at saturated coverage the adsorption energies at various sites are almost isoenergetic. The presented calculations show that a methanethiol layer on the regular Au(111) surface does not dimerize.

  4. Density functional study of the cysteine adsorption on Au nanoclusters

    NASA Astrophysics Data System (ADS)

    Pérez, L. A.; López-Lozano, X.; Garzón, I. L.

    2009-04-01

    The adsorption of the cysteine amino acid (H-SCβH2-CαH-NH2-COOH) on the Au55 cluster is investigated through density functional theory calculations. Two isomers, with icosahedral (Ih) and chiral (C1) geometries, of the Au55 cluster are used to calculate the adsorption energy of the cysteine on different facets of these isomers. Results, only involving the S(thiolate)-Au bonding show that the higher adsorption energies are obtained when the sulfur atom is bonded to an asymmetrical bridge site at the facet containing Au atoms with the lowest coordination of the C1 cluster isomer.

  5. Electron paramagnetic resonance in positively charged Au25 molecular nanoclusters.

    PubMed

    Akbari-Sharbaf, Arash; Hesari, Mahdi; Workentin, Mark S; Fanchini, Giovanni

    2013-01-14

    In this study, we investigated the unpaired electrons and singly occupied molecular orbitals (SOMO) of positively charged Au(25) molecular clusters using solid-state electron paramagnetic resonance (EPR). The EPR powder spectra of the positively charged (Au(25) (+)) and neutral (Au(25) (0)) species of Au(25) are discussed and compared. Our study demonstrates that Au(25) (+) is paramagnetic with a SOMO that is mostly localized about the central gold atom in the core of the molecule and possesses a strong p-type atomic character. The unpaired electron spin is demonstrated to strongly interact with the nuclear spins from other (197)Au nuclei in the core of Au(25) (+) molecules and the hyperfine tensor describing such interaction was extracted from the comparison of the EPR spectra with quantum mechanical simulations assuming an anisotropic structure of the core. Our simulations suggest that the core of Au(25) (+) molecular clusters is more distorted than in the corresponding neutral counterpart. They also confirm previous hypotheses suggesting that the icosahedral core of Au(25) (+) experiences contraction with decreasing temperature. PMID:23320681

  6. Atomistic simulations of Au-silica nanocomposite film growth

    SciTech Connect

    Khan, Saif A.; Heinig, K.-H.; Avasthi, D. K.

    2011-05-01

    The growth of Au-silica nanocomposite film is simulated in the framework of kinetic three dimensional lattice Monte Carlo simulations considering the basic phenomena in the deposition process. In case of co-sputter deposition, the growth kinetics of nanoparticles has been studied taking into consideration the effect of the energetic sputtered species reaching the surface of the film during deposition. Formation of Au nanorod like structures are predicted under certain growth conditions particularly when surface diffusion assisted phase separation plays the dominant role and bulk kinetics is frozen. The observed dependence of the Au nanoparticle size on Au/silica ratio is in agreement with the experimental results.

  7. Enhanced photoluminescence in Au-embedded ITO nanowires.

    PubMed

    Kim, Hyunsu; Park, Sunghoon; Jin, Changhyun; Lee, Chongmu

    2011-12-01

    Gold (Au)-embedded indium tin oxide (ITO) nanowires were synthesized by thermal evaporation of a mixture of In(2)O(3,) SnO(2) and graphite powders on Si (100) substrates coated with Au thin films followed by annealing. At the initial stages of annealing, Au formed a continuous linear core located along the long axis of each ITO nanowire. The morphology of the Au core changed from a continuous line to a discrete line, and then to a droplet-like chain, finally evolving into a peapod in which crystalline Au nanoparticles were encapsulated in crystalline ITO with increasing annealing temperature. The ITO nanowires with the Au core showed an emission band at ~380 nm in the ultraviolet region. The ultraviolet emission intensity increased rapidly with increasing annealing temperature. The intensity of emission from the Au-peapod ITO nanowires (annealed at 750 °C) was approximately 20 times higher than that of the emission from the Au-core/ITO-shell ITO nanowires with a continuous linear shaped-Au core (annealed at 550 °C). This ultraintense ultraviolet emission might have originated mainly from the enhanced crystalline quality of the annealed ITO nanowires. PMID:22087582

  8. Component conversion from pure Au nanorods to multiblock Ag-Au-Ag nanorods assisted by Pt nanoframe templates.

    PubMed

    Lee, Sangji; Jang, Hee-Jeong; Jang, Ho Young; Kim, Seong Kyu; Park, Sungho

    2016-07-14

    We developed a new method for synthesizing multiblock Ag-Au-Ag nanorods using Pt nanoframes that had been deposited on the edges of Au nanorod seeds. As a function of Au etching time, the length of the Au nanorod decreased symmetrically starting from the two ends, leading to the formation of empty inner space at the ends. Subsequent reduction of Ag ions could be selectively performed in the inner space confined by Pt nanoframes and the resulting Ag-Au-Ag nanorods exhibited characteristic LSPR modes originating from each block component (in a transverse direction) and SPR coupling (in a longitudinal direction). The high quality of the resulting multiblock nanorods enabled observation of the longitudinal quadrupole mode that was induced by Ag-Au SPR coupling in a long axis. The mode exhibited high sensitivity in accordance with the change in the surrounding media, demonstrating great potential for sensor applications. PMID:27315144

  9. Diffusion of the Linear CH3S-Au-SCH3 Complex on Au(111) from First Principles

    SciTech Connect

    Jiang, Deen; Dai, Sheng

    2009-01-01

    Recent experimental and computational advances have clearly established the importance of the linear alkylthiolate-Au-alkylthiolate (RS-Au-SR) complex at the interface between the thiolate groups and the gold surface. By using density functional theory-based first principles method, here we show that the elementary diffusion step of this linear complex on Au(111) has a barrier of only {approx}0.5 eV in the case of methylthiolate, indicating great mobility of the linear complex on Au(111). The role of this low barrier in the formation of a self-assembled monolayer of thiolate groups in the form of RS-Au-SR on Au(111) is discussed.

  10. Observation of D0 Meson Nuclear Modifications in Au +Au Collisions at √sNN =200 GeV

    NASA Astrophysics Data System (ADS)

    Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Alekseev, I.; Alford, J.; Anson, C. D.; Aparin, A.; Arkhipkin, D.; Aschenauer, E. C.; Averichev, G. S.; Banerjee, A.; Beavis, D. R.; Bellwied, R.; Bhasin, A.; Bhati, A. K.; Bhattarai, P.; Bichsel, H.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Bordyuzhin, I. G.; Borowski, W.; Bouchet, J.; Brandin, A. V.; Brovko, S. G.; Bültmann, S.; Bunzarov, I.; Burton, T. P.; Butterworth, J.; Caines, H.; Calderón de la Barca Sánchez, M.; Cebra, D.; Cendejas, R.; Cervantes, M. C.; Chaloupka, P.; Chang, Z.; Chattopadhyay, S.; Chen, H. F.; Chen, J. H.; Chen, L.; Cheng, J.; Cherney, M.; Chikanian, A.; Christie, W.; Chwastowski, J.; Codrington, M. J. M.; Contin, G.; Cramer, J. G.; Crawford, H. J.; Cui, X.; Das, S.; Davila Leyva, A.; De Silva, L. C.; Debbe, R. R.; Dedovich, T. G.; Deng, J.; Derevschikov, A. A.; Derradi de Souza, R.; Dhamija, S.; di Ruzza, B.; Didenko, L.; Dilks, C.; Ding, F.; Djawotho, P.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Du, C. M.; Dunkelberger, L. E.; Dunlop, J. C.; Efimov, L. G.; Engelage, J.; Engle, K. S.; Eppley, G.; Eun, L.; Evdokimov, O.; Eyser, O.; Fatemi, R.; Fazio, S.; Fedorisin, J.; Filip, P.; Finch, E.; Fisyak, Y.; Flores, C. E.; Gagliardi, C. A.; Gangadharan, D. R.; Garand, D.; Geurts, F.; Gibson, A.; Girard, M.; Gliske, S.; Greiner, L.; Grosnick, D.; Gunarathne, D. S.; Guo, Y.; Gupta, A.; Gupta, S.; Guryn, W.; Haag, B.; Hamed, A.; Han, L.-X.; Haque, R.; Harris, J. W.; Heppelmann, S.; Hirsch, A.; Hoffmann, G. W.; Hofman, D. J.; Horvat, S.; Huang, B.; Huang, H. Z.; Huang, X.; Huck, P.; Humanic, T. J.; Igo, G.; Jacobs, W. W.; Jang, H.; Judd, E. G.; Kabana, S.; Kalinkin, D.; Kang, K.; Kauder, K.; Ke, H. W.; Keane, D.; Kechechyan, A.; Kesich, A.; Khan, Z. H.; Kikola, D. P.; Kisel, I.; Kisiel, A.; Koetke, D. D.; Kollegger, T.; Konzer, J.; Koralt, I.; Kotchenda, L.; Kraishan, A. F.; Kravtsov, P.; Krueger, K.; Kulakov, I.; Kumar, L.; Kycia, R. A.; Lamont, M. A. C.; Landgraf, J. M.; Landry, K. D.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, J. H.; LeVine, M. J.; Li, C.; Li, W.; Li, X.; Li, X.; Li, Y.; Li, Z. M.; Lisa, M. A.; Liu, F.; Ljubicic, T.; Llope, W. J.; Lomnitz, M.; Longacre, R. S.; Luo, X.; Ma, G. L.; Ma, Y. G.; Madagodagettige Don, D. M. M. D.; Mahapatra, D. P.; Majka, R.; Margetis, S.; Markert, C.; Masui, H.; Matis, H. S.; McDonald, D.; McShane, T. S.; Minaev, N. G.; Mioduszewski, S.; Mohanty, B.; Mondal, M. M.; Morozov, D. A.; Mustafa, M. K.; Nandi, B. K.; Nasim, Md.; Nayak, T. K.; Nelson, J. M.; Nigmatkulov, G.; Nogach, L. V.; Noh, S. Y.; Novak, J.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Oh, K.; Ohlson, A.; Okorokov, V.; Oldag, E. W.; Olvitt, D. L.; Pachr, M.; Page, B. S.; Pal, S. K.; Pan, Y. X.; Pandit, Y.; Panebratsev, Y.; Pawlak, T.; Pawlik, B.; Pei, H.; Perkins, C.; Peryt, W.; Pile, P.; Planinic, M.; Pluta, J.; Poljak, N.; Porter, J.; Poskanzer, A. M.; Pruthi, N. K.; Przybycien, M.; Pujahari, P. R.; Putschke, J.; Qiu, H.; Quintero, A.; Ramachandran, S.; Raniwala, R.; Raniwala, S.; Ray, R. L.; Riley, C. K.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Ross, J. F.; Roy, A.; Ruan, L.; Rusnak, J.; Rusnakova, O.; Sahoo, N. R.; Sahu, P. K.; Sakrejda, I.; Salur, S.; Sandweiss, J.; Sangaline, E.; Sarkar, A.; Schambach, J.; Scharenberg, R. P.; Schmah, A. M.; Schmidke, W. B.; Schmitz, N.; Seger, J.; Seyboth, P.; Shah, N.; Shahaliev, E.; Shanmuganathan, P. V.; Shao, M.; Sharma, B.; Shen, W. Q.; Shi, S. S.; Shou, Q. Y.; Sichtermann, E. P.; Singaraju, R. N.; Skoby, M. J.; Smirnov, D.; Smirnov, N.; Solanki, D.; Sorensen, P.; Spinka, H. M.; Srivastava, B.; Stanislaus, T. D. S.; Stevens, J. R.; Stock, R.; Strikhanov, M.; Stringfellow, B.; Sumbera, M.; Sun, X.; Sun, X. M.; Sun, Y.; Sun, Z.; Surrow, B.; Svirida, D. N.; Symons, T. J. M.; Szelezniak, M. A.; Takahashi, J.; Tang, A. H.; Tang, Z.; Tarnowsky, T.; Thomas, J. H.; Timmins, A. R.; Tlusty, D.; Tokarev, M.; Trentalange, S.; Tribble, R. E.; Tribedy, P.; Trzeciak, B. A.; Tsai, O. D.; Turnau, J.; Ullrich, T.; Underwood, D. G.; Van Buren, G.; van Nieuwenhuizen, G.; Vandenbroucke, M.; Vanfossen, J. A.; Varma, R.; Vasconcelos, G. M. S.; Vasiliev, A. N.; Vertesi, R.; Videbæk, F.; Viyogi, Y. P.; Vokal, S.; Vossen, A.; Wada, M.; Wang, F.; Wang, G.; Wang, H.; Wang, J. S.; Wang, X. L.; Wang, Y.; Wang, Y.; Webb, G.; Webb, J. C.; Westfall, G. D.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, Y. F.; Xiao, Z.; Xie, W.; Xin, K.; Xu, H.; Xu, J.; Xu, N.; Xu, Q. H.; Xu, Y.; Xu, Z.; Yan, W.; Yang, C.; Yang, Y.; Yang, Y.; Ye, Z.; Yepes, P.; Yi, L.; Yip, K.; Yoo, I.-K.; Yu, N.; Zawisza, Y.; Zbroszczyk, H.; Zha, W.; Zhang, J. B.; Zhang, J. L.; Zhang, S.; Zhang, X. P.; Zhang, Y.; Zhang, Z. P.; Zhao, F.; Zhao, J.; Zhong, C.; Zhu, X.; Zhu, Y. H.; Zoulkarneeva, Y.; Zyzak, M.; STAR Collaboration

    2014-10-01

    We report the first measurement of charmed-hadron (D0) production via the hadronic decay channel (D0→K-+π+) in Au +Au collisions at √sNN =200 GeV with the STAR experiment. The charm production cross section per nucleon-nucleon collision at midrapidity scales with the number of binary collisions, Nbin, from p +p to central Au +Au collisions. The D0 meson yields in central Au +Au collisions are strongly suppressed compared to those in p+p scaled by Nbin, for transverse momenta pT>3 GeV /c, demonstrating significant energy loss of charm quarks in the hot and dense medium. An enhancement at intermediate pT is also observed. Model calculations including strong charm-medium interactions and coalescence hadronization describe our measurements.

  11. Heterostructured Au/Pd-M (M = Au, Pd, Pt) nanoparticles with compartmentalized composition, morphology, and electrocatalytic activity.

    PubMed

    Lutz, Patrick S; Bae, In-Tae; Maye, Mathew M

    2015-10-14

    The synthesis, processing, and galvanic exchange of three heterostructured nanoparticle systems is described. The surface accessibility and redox potential of a Au/Pd-Ag dumbbell nanoparticle, where a Au/Pd core/shell region, and a silver region make up the domains, was used to prepare the new nanostructures with controlled composition, morphology, and microstructure. Results indicate that the silver domain was particularly susceptible to galvanic displacement, and was exchanged to Au/Pd-M (M = Au, Pd, Pt). Interestingly, the dumbbell morphology remained after exchange, and the silver region was transformed to hollow, parachute, or concentric domains respectively. The morphology and microstructure change was visualized via TEM and HRTEM, and the composition changes were probed via STEM-EDS imaging and XPS. The electrocatalytic activity of the Au/Pd-M towards methanol oxidation was studied, with results indicating that the Au/Pd-Pt nanoparticles had high activity attributed to the porous nature of the platinum domains. PMID:26351824

  12. Component conversion from pure Au nanorods to multiblock Ag-Au-Ag nanorods assisted by Pt nanoframe templates

    NASA Astrophysics Data System (ADS)

    Lee, Sangji; Jang, Hee-Jeong; Jang, Ho Young; Kim, Seong Kyu; Park, Sungho

    2016-06-01

    We developed a new method for synthesizing multiblock Ag-Au-Ag nanorods using Pt nanoframes that had been deposited on the edges of Au nanorod seeds. As a function of Au etching time, the length of the Au nanorod decreased symmetrically starting from the two ends, leading to the formation of empty inner space at the ends. Subsequent reduction of Ag ions could be selectively performed in the inner space confined by Pt nanoframes and the resulting Ag-Au-Ag nanorods exhibited characteristic LSPR modes originating from each block component (in a transverse direction) and SPR coupling (in a longitudinal direction). The high quality of the resulting multiblock nanorods enabled observation of the longitudinal quadrupole mode that was induced by Ag-Au SPR coupling in a long axis. The mode exhibited high sensitivity in accordance with the change in the surrounding media, demonstrating great potential for sensor applications.We developed a new method for synthesizing multiblock Ag-Au-Ag nanorods using Pt nanoframes that had been deposited on the edges of Au nanorod seeds. As a function of Au etching time, the length of the Au nanorod decreased symmetrically starting from the two ends, leading to the formation of empty inner space at the ends. Subsequent reduction of Ag ions could be selectively performed in the inner space confined by Pt nanoframes and the resulting Ag-Au-Ag nanorods exhibited characteristic LSPR modes originating from each block component (in a transverse direction) and SPR coupling (in a longitudinal direction). The high quality of the resulting multiblock nanorods enabled observation of the longitudinal quadrupole mode that was induced by Ag-Au SPR coupling in a long axis. The mode exhibited high sensitivity in accordance with the change in the surrounding media, demonstrating great potential for sensor applications. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr03484e

  13. Mesomorphic lamella rolling of au in vacuum.

    PubMed

    Huang, Chang-Ning; Chen, Shuei-Yuan; Shen, Pouyan

    2009-01-01

    Lamellar nanocondensates in partial epitaxy with larger-sized multiply twinned particles (MTPs) or alternatively in the form of multiple-walled tubes (MWTs) having nothing to do with MTP were produced by the very energetic pulse laser ablation of Au target in vacuum under specified power density and pulses. Transmission electron microscopic observations revealed (111)-motif diffraction and low-angle scattering. They correspond to layer interspacing (0.241-0.192 nm) and the nearest neighbor distance (ca. 0.74-0.55 nm) of atom clusters within the layer, respectively, for the lamella, which shows interspacing contraction with decreasing particle size under the influence of surface stress and rolls up upon electron irradiation. The uncapped MWT has nearly concentric amorphous layers interspaced by 0.458-0.335 nm depending on dislocation distribution and becomes spherical onions for surface-area reduction upon electron dosage. Analogous to graphene-derived tubular materials, the lamella-derived MWT of Au could have pentagon-hexagon pair at its zig-zag junction and useful optoelectronic properties worthy of exploration. PMID:20628452

  14. Interplanetary magnetic clouds at 1 AU

    NASA Technical Reports Server (NTRS)

    Klein, L. W.; Burlaga, L. F.

    1981-01-01

    Magnetic clouds are defined as regions with a radial dimension approximately 0.25 AU (at 1 AU) in which the magnetic field strength is high and the magnetic field direction changes appreciably by means of rotation of one component of B nearly parallel to a plane. The magnetic field geometry in such a magnetic cloud is consistent with that of a magnetic loop, but it cannot be determined uniquely. Forty-five clouds were identified in interplanetary data obtained near Earth between 1967 and 1978; at least one cloud passed the Earth every three months. Three classes of clouds were identified, corresponding to the association of a cloud with a shock, a stream interface, or a CME. There are approximately equal numbers of clouds in each class, and the three types of clouds might be different manifestations of a coronal transient. The magnetic pressure inside the clouds is higher than the ion pressure and the sum is higher than the pressure of the material outside of the cloud.

  15. Mesomorphic Lamella Rolling of Au in Vacuum

    NASA Astrophysics Data System (ADS)

    Huang, Chang-Ning; Chen, Shuei-Yuan; Shen, Pouyan

    2009-11-01

    Lamellar nanocondensates in partial epitaxy with larger-sized multiply twinned particles (MTPs) or alternatively in the form of multiple-walled tubes (MWTs) having nothing to do with MTP were produced by the very energetic pulse laser ablation of Au target in vacuum under specified power density and pulses. Transmission electron microscopic observations revealed (111)-motif diffraction and low-angle scattering. They correspond to layer interspacing (0.241-0.192 nm) and the nearest neighbor distance (ca. 0.74-0.55 nm) of atom clusters within the layer, respectively, for the lamella, which shows interspacing contraction with decreasing particle size under the influence of surface stress and rolls up upon electron irradiation. The uncapped MWT has nearly concentric amorphous layers interspaced by 0.458-0.335 nm depending on dislocation distribution and becomes spherical onions for surface-area reduction upon electron dosage. Analogous to graphene-derived tubular materials, the lamella-derived MWT of Au could have pentagon-hexagon pair at its zig-zag junction and useful optoelectronic properties worthy of exploration.

  16. Mesomorphic Lamella Rolling of Au in Vacuum

    PubMed Central

    2009-01-01

    Lamellar nanocondensates in partial epitaxy with larger-sized multiply twinned particles (MTPs) or alternatively in the form of multiple-walled tubes (MWTs) having nothing to do with MTP were produced by the very energetic pulse laser ablation of Au target in vacuum under specified power density and pulses. Transmission electron microscopic observations revealed (111)-motif diffraction and low-angle scattering. They correspond to layer interspacing (0.241–0.192 nm) and the nearest neighbor distance (ca. 0.74–0.55 nm) of atom clusters within the layer, respectively, for the lamella, which shows interspacing contraction with decreasing particle size under the influence of surface stress and rolls up upon electron irradiation. The uncapped MWT has nearly concentric amorphous layers interspaced by 0.458–0.335 nm depending on dislocation distribution and becomes spherical onions for surface-area reduction upon electron dosage. Analogous to graphene-derived tubular materials, the lamella-derived MWT of Au could have pentagon–hexagon pair at its zig-zag junction and useful optoelectronic properties worthy of exploration. PMID:20628452

  17. Ordered arrays of Au catalysts by FIB assisted heterogeneous dewetting

    NASA Astrophysics Data System (ADS)

    Benkouider, A.; Ronda, A.; David, T.; Favre, L.; Abbarchi, M.; Naffouti, M.; Osmond, J.; Delobbe, A.; Sudraud, P.; Berbezier, I.

    2015-12-01

    Synthesizing Au0.8Si0.2 nanocatalysts that are homogeneous in size and have controlled position is becoming a challenging and crucial prequisite for the fabrication of ordered semiconductor nanowires. In this study, Au0.8Si0.2 nanocatalysts are synthesized via dewetting of Au layers on Si(111) during thermal annealing in an ultra-high vacuum. In the first part of the paper, the mechanism of homogeneous dewetting is analyzed as a function of the Au-deposited thickness (h Au). We distinguish three different dewetting regimes: (I) for a low thickness ({h}{{Au}}≤slant 0.4 {nm}), a submonolyer coverage of Au is stabilized and there is no dewetting. (II) For an intermediate thickness (0.4 {nm}\\lt {h}{Au}≤slant 5 {nm}), there is both dewetting and Au0.8Si0.2 phase formation. The size and density of the Au0.8Si0.2 clusters are directly related to h Au. When cooling down to room temperature, the clusters decompose and reject the Si at the Au/Si substrate interface. (III) For a large thickness ({h}{{Au}}\\gt 5 {nm}), only dewetting takes place, without forming AuSi clusters. In this regime, the dewetting is kinetically controlled by the self-diffusion of Au (activation energy ∼0.43 eV) without evidence of an Si-alloying effect. As a practical consequence, when relying solely on the homogeneous dewetting of Au/Si(111) to form the Au0.8Si0.2 catalysts (without a supply of Si atoms from vapor), regime II should be used to obtain good size and density control. In the second part of the paper, a process for ordering the catalysts using focused ion beam-(FIB) assisted dewetting (heterogeneous dewetting) is developed. We show that no matter what the FIB milling conditions and the Au nominal thickness are, dewetting is promoted by ion beam irradiation and is accompanied by the formation of Au0.8Si0.2 droplets. The droplets preferentially form on the patterned areas, while in similar annealing conditions, they do not form on the unpatterned areas. This behavior is attributed

  18. Coating of a layer of Au on Al13 : The findings of icosahedral Al@Al12Au20- and Al12Au202- fullerenes using ab initio pseudopotential calculations

    NASA Astrophysics Data System (ADS)

    Kumar, Vijay

    2009-02-01

    We report results of ab initio pseudopotential calculations on the nanocoating of gold on an icosahedral Al13 cluster and the findings of icosahedrally symmetric endohedral Al@Al12Au20- and empty cage Al12Au202- compound fullerenes formed of metal atoms. Twelve Al atoms cap the pentagonal faces of a dodecahedral Au20 cage in which each Au atom has three Al atoms and three Au atoms as nearest neighbors. Mixing of Al13 and Au20 magic clusters leads to a large heat of formation of 0.55 eV/atom and high stability of the Al@Al12Au20 compound fullerene. The binding energies of Al12Au20 and Al@Al12Au20 are 3.017 and 3.007 eV/atom, respectively, which are much larger than 2.457 eV/atom for Au32 fullerene, leading to the possibility of their high abundance.

  19. Facile synthesis of ultrathin Au nanorods by aging the AuCl(oleylamine) complex with amorphous Fe nanoparticles in chloroform.

    PubMed

    Li, Zhengquan; Tao, Jing; Lu, Xianmao; Zhu, Yimei; Xia, Younan

    2008-09-01

    Despite plenty of reports on the preparation of Au nanorods, it remains challenging to grow uniform Au nanorods with diameters below 5 nm. In this communication, we demonstrate the facile synthesis of ultrathin Au nanorods with a uniform diameter of 2 nm and an average aspect ratio of 30. The synthesis involves the room-temperature aging of a mixture of the [AuCl(oleylamine)] complex with amorphous Fe nanoparticles in chloroform. Analysis of the growth mechanism indicates that Au nanoparticles with a high density of defects were formed at early stages, followed by etching and redeposition process that gradually led to the growth of ultrathin Au nanorods along the 111 direction. This growth mechanism is different from the mechanism recently reported for ultrathin Au nanowires (ref ), where the [AuCl(oleylamine)] complex is assembled into polymer chains followed by reduction to form wires, although the template effect of oleylamine for the formation of ultrathin Au nanorods cannot be completely ruled out. PMID:18681484

  20. Gold Apes Hydrogen. The Structure and Bonding in the Planar B7Au2- and B7Au2 Clusters

    SciTech Connect

    Zhai, Hua JIN.; Wang, Lai S.; Zubarev, Dmitry Y.; Boldyrev, Alexander I.

    2006-02-09

    We produced the B7Au2- mixed cluster and studied its electronic structure and chemical bonding using photoelectron spectroscopy and ab initio calculations. The photoelectron spectra of B7Au2- were observed to be relatively simple with vibrational resolution, in contrast to the complicated spectra observed for pure B7-, which had contributions from three isomers (Alexandrova et al., J. Phys. Chem. A, 2004, 108, 3509). Theoretical calculations show that B7Au2- possesses an extremely stable planar structure, identical to that of B7H2-, demonstrating that Au mimics H in its bonding to boron, analogous to the Au-Si bonding. The ground state structure of B7Au2- (B7H2-) can be viewed as adding two Au (H) atoms to the terminal B atoms of a higher-lying planar isomer of B7-. The bonding and stability in the planar B7Au2- (B7H2-) clusters are elucidated on the basis of the strong covalent B-Au (H) bonding and the concepts of aromaticity/antiaromaticity in these systems.

  1. Ultrafast charge carrier dynamics in Au/semiconductor nanoheterostructures

    NASA Astrophysics Data System (ADS)

    Lambright, Scott

    The charge carrier dynamics in several Au/semiconductor core/shell heterostructures were examined. Firstly, Au/CdS core/shell nanocomposites were synthesized in a four step procedure culminating in a cation exchange performed on the shell. Previous studies of the ultrafast carrier dynamics in Au/CdS nanocomposites with epitaxial boundary regions reported the suppression of plasmon character in transient absorption spectra accompanied by broadband photoinduced absorption. The coupling of electron wavefunctions with lattice defects at the boundary of the two domains has been blamed for these phenomena. In the current study, transmission electron micrographs of Au/CdS synthesized using cation exchange showed no evidence of strain on the lattice of either component, while femtosecond transient absorption data show the retention of bleach regions attributed to CdS's 1S(e)-1S3/2(h) transition and Au's plasmon resonance. Accelerated rates of bleach recovery for both excitations ( tauexiton ≈ 300 ps, tauplasmon ≈ .7 ps) indicated that the interaction of Au and CdS domains leads to faster relaxation to their respective photoexcitations when compared to relaxation times in isolated Au and CdS nanoparticles. It was believed that the Au/CdS boundary was non-epitaxial in the presented core/shell nanocomposites. Secondly, these non-epitaxial Au/CdS core/shells were subsequently used to demonstrate near-field energy transfer from 5 nm diameter Au cores to CdS-encapsulated CdSe quantum dots. To this end, Au/CdS and CdSe/CdS nanocrystals were embedded in semiconductor-matrix-encapsulated-nanocrystal-arrays (SMENA) together. The encapsulation of both domains in the high band-gap semiconductor CdS was a means to suppress charge transfer between the two nanoparticles. The fluorescence intensity in these films was enhanced 6-fold in some cases as a result of the presence of Au domains. It was also demonstrated that the fluorescence enhancement was independent of the potential

  2. Gas phase selective hydrogenation over oxide supported Ni-Au.

    PubMed

    Cárdenas-Lizana, Fernando; Keane, Mark A

    2015-11-14

    The chemoselective continuous gas phase (T = 573 K; P = 1 atm) hydrogenation of nitroarenes (p-chloronitrobenzene (p-CNB) and m-dinitrobenzene (m-DNB)) has been investigated over a series of oxide (Al2O3 and TiO2) supported Au and Ni-Au (1 : 10 mol ratio; 0.1-1 mol% Au) catalysts. Monometallic supported Au with mean particle size 3-9 nm promoted exclusive formation of p-chloroaniline (p-CAN) and m-nitroaniline (m-NAN). Selective hydrogenation rate was higher over smaller Au particles and can be attributed to increased surface hydrogen (from TPD measurements) at higher metal dispersion. (S)TEM analysis has confirmed an equivalent metal particle size for the supported bimetallics at the same Au loading where TPR indicates Ni-Au interaction and EDX surface mapping established Ni in close proximity to Au on isolated nanoparticles with a composition (Au/Ni) close to the bulk value (= 10). Increased spillover hydrogen due to the incorporation of Ni in the bimetallics resulted in elevated -NO2 group reduction rate. Full selectivity to p-CAN was maintained over all the bimetallic catalysts. Conversion of m-DNB over the lower loaded Ni-Au/Al2O3 generated m-NAN as sole product. An increase in Ni content (0.01 → 0.1 mol%) or a switch from Al2O3 to TiO2 as support resulted in full -NO2 reduction (to m-phenylenediamine). Our results demonstrate the viability of Ni-promotion of Au in the continuous production of functionalised anilines. PMID:25752655

  3. CO oxidation on h-BN supported Au atom

    SciTech Connect

    Gao Min; Lyalin, Andrey; Taketsugu, Tetsuya

    2013-01-21

    The mechanism of CO oxidation by O{sub 2} on Au atoms supported on the pristine and defected hexagonal boron nitride (h-BN) surface has been studied theoretically using density functional theory. It is found that O{sub 2} binds stronger than CO on an Au atom supported on the defect free h-BN surface and h-BN surface with nitrogen vacancy (V{sub N}-h-BN), but weaker than CO on a free Au atom or Au trapped by a boron vacancy (V{sub B}-h-BN). The excess of the positive or negative charge on Au can considerably change its catalytic properties and enhance activation of the adsorbed O{sub 2}. Coadsorption of CO and O{sub 2} on Au, Au/V{sub N}-h-BN, and Au/V{sub B}-h-BN results in additional charge transfer to O{sub 2}. Various pathways of the CO oxidation reaction by molecular oxygen are studied. We found two different pathways for CO oxidation: a two-step pathway where two CO{sub 2} molecules are formed independently, and a self-promotion pathway where oxidation of the first CO molecule is promoted by the second CO molecule. Interaction of Au with the defect-free and defected h-BN surfac