Order of the Runge-Kutta Method and Evolution of the Stability Region

In this article, we demonstrate through specific examples that the evolution of the size of the absolute stability regions of Runge–Kutta methods for ordinary differential equation does not depend on the order of methods.We would like to express our deepest appreciation and gratitude to Professor Sergey Khashin of Ivanovo State University who provided us the possibility to coordinate and complete this article

Distribution, incidence and severity of viral diseases of yam (Dioscorea spp.) in Côte d’Ivoire

A survey was conducted in major yam cultivation zones in Côte d’Ivoire in 2009 to determine the incidence, severity of viral diseases, and viruses associated with the infected plants. Incidence and severity of the viral diseases were estimated based on symptoms. Enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR)-based techniques were used for the detection of Yam mosaic virus (YMV), Cucumber mosaic virus (CMV), Dioscorea mottle virus (DMoV) and yam badnaviruses in the sampled yam leaves. Disease incidence varied from 0 to 90% and symptom severity from 1 to 5. There were significant difference in incidence and severity between different agro-ecological zones (P < 0.001). About 36% of the samples tested positive to YMV, ca. 1.5% tested positive to CMV, ca. 39.1% samples tested positive to yam infecting badnaviruses, and none of the samples tested positive to DMoV. This study demonstrated high incidence of virus diseases in all the yam production regions and warrants implementation of virus disease control measures.Keywords: Yam, enzyme-linked immunosorbent assay (ELISA), polymerase chain reaction (PCR), viruses, Côte d’IvoireAfrican Journal of Biotechnology, Vol. 13(3), pp. 465-470, 15 January, 201

Health & Demographic Surveillance System Profile: The Taabo Health and Demographic Surveillance System, Côte d'Ivoire

The Taabo Health and Demographic Surveillance System (HDSS) is located in south-central Côte d'Ivoire, approximately 150 km north-west of Abidjan. The Taabo HDSS started surveillance activities in early 2009 and the man-made Lake Taabo is a key eco-epidemiological feature. Since inception, there has been a strong interest in research and integrated control of water-associated diseases such as schistosomiasis and malaria. The Taabo HDSS has generated setting-specific evidence on the impact of targeted interventions against malaria, schistosomiasis and other neglected tropical diseases. The Taabo HDSS consists of a small town, 13 villages and over 100 hamlets. At the end of 2013, a total population of 42 480 inhabitants drawn from 6707 households was under surveillance. Verbal autopsies have been conducted to determine causes of death. Repeated cross-sectional epidemiological surveys on approximately 5-7% of the population and specific, layered-on haematological, parasitological and questionnaire surveys have been conducted. The Taabo HDSS provides a database for surveys, facilitates interdisciplinary research, as well as surveillance, and provides a platform for the evaluation of health interventions. Requests to collaborate and to access data are welcome and should be addressed to the secretariat of the Centre Suisse de Recherches Scientifiques en Côte d'Ivoire: [[email protected]

Rapid detection of potyviruses from crude plant extracts

Potyviruses (genus Potyvirus; family Potyviridae) are widely distributed and represent one of the most economically important genera of plant viruses. Therefore, their accurate detection is a key factor in developing efficient control strategies. However, this can sometimes be problematic particularly in plant species containing high amounts of polysaccharides and polyphenols such as yam (Dioscorea spp.). Here, we report the development of a reliable, rapid and cost-effective detection method for the two most important potyviruses infecting yam based on reverse transcription-recombinase polymerase amplification (RT-RPA). The developed method, named ‘Direct RT-RPA’, detects each target virus directly from plant leaf extracts prepared with a simple and inexpensive extraction method avoiding laborious extraction of high-quality RNA. Direct RT-RPA enables the detection of virus-positive samples in under 30 min at a single low operation temperature (37 °C) without the need for any expensive instrumentation. The Direct RT-RPA tests constitute robust, accurate, sensitive and quick methods for detection of potyviruses from recalcitrant plant species. The minimal sample preparation requirements and the possibility of storing RPA reagents without cold chain storage, allow Direct RT-RPA to be adopted in minimally equipped laboratories and with potential use in plant clinic laboratories and seed certification facilities worldwide

International equatorial electrojet year : the African sector

International audienceThis paper presents the IEEY project in the African sector. The amount of our interpreted data is presently too short to allow proper scientific conclusions. Nevertheless, fist typical results illustrate our network possibilities. Some preliminary observations are briefly pre- , sented for their interest towards immediate research goals

Distribution, incidence and severity of viral diseases of yam (Dioscorea spp.) in Cote dIvoire

A survey was conducted in major yam cultivation zones in Côte d’Ivoire in 2009 to determine the incidence, severity of viral diseases, and viruses associated with the infected plants. Incidence and severity of the viral diseases were estimated based on symptoms. Enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR)-based techniques were used for the detection of Yam mosaic virus (YMV), Cucumber mosaic virus (CMV), Dioscorea mottle virus (DMoV) and yam badnaviruses in the sampled yam leaves. Disease incidence varied from 0 to 90% and symptom severity from 1 to 5. There were significant difference in incidence and severity between different agro-ecological zones (P < 0.001). About 36% of the samples tested positive to YMV, ca. 1.5% tested positive to CMV, ca. 39.1% samples tested positive to yam infecting badnaviruses, and none of the samples tested positive to DMoV. This study demonstrated high incidence of virus diseases in all the yam production regions and warrants implementation of virus disease control measures

Contamination des eaux de puits traditionnels par les nitrates sur le bassin versant de la Lobo (Buyo, sudouest de la Côte d’Ivoire)

Objective: Contamination of groundwater by nitrates is a real public health concern that is currently being paid a particular attention worldwide. This study investigates the spatial distribution of nitrates in traditional water supply wells in the Lobo's watershed, in order to derive appropriate measures to protect groundwater resources in this region. Methodology and Results: the origin of nitrate water from traditional wells of Lobo’s watershed was determined through the analysis of nitrate concentrations. The samples were collected in March (dry season) and June (wet season) 2007 on the waters of traditional wells in two villages Gbili and Logbozoa and camps on the lobo’s watershed. The results show that nitrate concentrations vary on the watershed. In general, concentrations range from 0 mg.L-1 to 71,26 mg L-1. Wells with a concentration above the guideline value of WHO (50 mg.L-1) are found in Buyo and both villages Gbili and Logbozoa. On the other hand, wells of Tchemasso, Buyo Provisoire and camps have nitrate levels complying with the standard. Conclusion and application of results: Well waters of Buyo and two villages Gbili and Logbozoa with higher population densities are richer in nitrate. On the contrary, wells of Tchemasso, Buyo Provisoire and camps, with lower population density and sometimes with wells in plantations have low levels. Thus, the high population density, coupled with the lack of sanitation and incorrectly installed latrines, is the main cause of high nitrate levels in traditional water supply wells in the Lobo’s Watershed. Water wells located in plantations with low nitrate levels show that agriculture is not responsible for the contamination of water in this area. In the short term, an appropriately designed awareness campaign on sanitation and public health directed to the populations should be initiated to allow improving and protecting well water quality in the Lobo’s watershed.Keywords: anthropogenic activity; groundwater; pollution; physico-chemical quality

Chlorine-Susceptible and Chlorine-Resistant Type 021N Bacteria Occurring in Bulking Activated Sludges

Two filamentous bacteria causing bulking in two activated sludges were examined. Investigations using morphological features, staining techniques, and fluorescent in situ hybridization identified both filaments as type 021N. However, an examination of the effect of chlorine on the sludges revealed a chlorine-susceptible type 021N in one sludge and a chlorine-resistant type 021N in the other

First Report of African Eggplant Yellowing Virus on Tomato Exhibiting Necrotic Yellowing Symptoms in Northern Côte d’Ivoire

International audienc