Spectral Model for Soybean Yield Estimate Using MODIS/EVI Data

Attaining reliable and timely agricultural estimates is very important everywhere, and in Brazil, due to its characteristics, this is especially true. In this study, estimations of crop production were made based on the temporal profiles of the Enhanced Vegetation Index (EVI) obtained from Moderate Resolution Imaging Spectroradiometer (MODIS) images. The objective was to evaluate the coupled model (CM) performance of crop area and crop yield estimates based solely on MODIS/EVI as input data in Rio Grande do Sul State, which is characterized by high variability in seasonal soybean yields, due to different crop development conditions. The resulting production estimates from CM were compared to official agricultural statistics of Brazilian Institute of Geography and Statistics (IBGE) and the National Company of Food Supply (CONAB) at different levels from 2000/2001 to 2010/2011 crop years. Results obtained with CM indicate that its application is able to generate timely production estimates for soybean both at municipality and local levels. Validation estimates with CM at State level obtained R2 = 0.95. Combining all cropping years at municipality level, estimates were highly correlated to official statistics from IBGE, with R2 = 0.91 and RMSD = 10,840 tons. Spatially interpolated comparisons of yield maps obtained from the CM estimates and IBGE data also showed visual similarity in their spatial distribution. Local level comparisons were performed and presented R2 = 0.95. Implications of this work point out that time-series analysis of production estimates are able to provide anticipated spatial information prior to the soybean harvest.

Paleohydrological Reconstruction from Late Holocene Records in Interdune Lakes(N’Guigmi,Northern Bank of the Lake Chad,Niger)

An old erg covers the northern part of the Lake Chad basin. This dune landform allowed the formation of many interdune ponds of various sizes. Still present in certain zones where the groundwater level is high (e.g. Kanem, southern Manga), these ponds formed in the past a vast network of lacustrine microsystems, as shown by the nature and the distribution of their deposits. In the Manga, these interdune deposits represent the main sedimentary records of the Holocene environmental succession. Their paleobiological (pollens, diatoms, ostracods) and geochemical (δ18O, δ13C, Sr/Ca) contents are often the basis for paleoenvironmental reconstruction. On the other hand, their sedimentological characters are rarely exploited. This study of palustro-lacustrine deposits of the Holocene N’Guigmi lake (northern bank of the Lake Chad;Niger) is based on the relationships between the sedimentological features and the climato-hydrological fluctuations. The mineralogical parameters (e.g. calcium carbonate content, clay mineralogy) and the nature of autochthonous mineralization (i.e. amorphous silica, clays, calcium carbonates) can be interpreted using a straightforward hydro-sedimentary model. Established to explain the geochemical dynamics of Lake Chad, this model is based on a biogeochemical cycle of the main elements (i.e. silicium, calcium) directly controlled by the local hydrological balance (i.e. rainfall/evaporation ratio). All these results show that a detailed study of sedimentological features can provide important paleohydrological informations about the regional aridification since ca 6500 14C BP.

Diagnostic of the diurnal cycle of turbulence of the Equatorial Atlantic Ocean upper boundary layer

This work is an attempt to diagnose the turbu-lence field of the equatorial Atlantic Ocean dur-ing the dry period when the mixed layer is more highly developed using the General Ocean Turbulence Model (GOTM). A relaxation scheme assimilates the vertical profiles of in situ ob-servations (current velocity, sea temperature and salinity) during simulations. In the absence of direct turbulence observations and modeling studies of the equatorial Atlantic Ocean, the results are compared qualitatively to observed and simulated results for the equatorial Pacific Ocean. Similarities are noted between the At-lantic simulation and previous studies per-formed in the Pacific Ocean. The mechanism of nocturnal turbulence production, namely deep- cycle turbulence, is well captured by GOTM si-mulations. This deep nocturnal turbulence ap-pears rather suddenly during the night in the simulations and consequently seems to be un-related to surface wind and radiation forcing.

Epidemiology of onchocerciasis-associated epilepsy in the Mbam and Sanaga river valleys of Cameroon:impact of more than 13 years of ivermectin

Background:A high epilepsy prevalence has been reported in several onchocerciasis-endemic villages along the Mbam and Sanaga river valleys in Cameroon,including Bilomo and Kelleng.We sought to determine the prevalence of epilepsy in these two villages following more than 13 years of community-directed treatment with ivermectin(CDTI).Methods:Door-to-door surveys were performed on the entire resident population in the villages in August 2017 and January 2018.Epilepsy was diagnosed using a 2-step approach:administration of a standardized 5-item questionnaire followed by confirmation by a neurologist.Previously published diagnostic criteria for onchocerciasis-associated epilepsy(OAE)were used.Ov16 serology was done for children aged 7-10 years to assess onchocerciasis transmission.Findings were compared with previous data from these two villages.Results:A total of 1525 individuals(1321 in Bilomo and 204 in Kelleng)in 233 households were surveyed in both villages.The crude prevalence of epilepsy was 4.6%in Bilomo(2017)and 7.8%in Kelleng(2018),including 12(15.6%of cases)persons with epilepsy(PWE)with nodding seizures.The age and sex-standardized prevalence in Kelleng decreased from 13.5%in 2004 to 9.3%in 2018(P<0.001).The median age of PWE shifted from 17(IQR:12-22)years to 24(IQR:20-30)years in Bilomo(P<0.001);and slightly from 24(IQR:14-34)years to 28(IQR:21.25-36.75)years in Kelleng(P=0.112).Furthermore,47.6%of all tested children between 7 and 10 years had Ov16 antibodies.Conclusions:There is a decrease in epilepsy prevalence after 13 years and more of CDTI in both villages.The age-shift observed in PWE suggests that ivermectin may prevent OAE in younger residents.Ov16 seropositivity in children indicates ongoing onchocerciasis transmission possibly due to suboptimal control measures.Our findings support the existence of OAE in Cameroon and highlight the need to strengthen onchocerciasis elimination programs.

Rainfall-Runoff Simulation in Part of Lower Niger Basin

Water resources assessment in poorly gauged and ungauged basins demand supportive rainfall-runoff estimation, while resolving practical water resource management and planning issues. In this study, the research method employed involves rainfall-runoff modeling and simulation with proper efficiency criteria evaluation using the MODMENS modeling platform, a numerical rainfall-runoff semi-distributed GR2M conceptual lumped model. The rainfall-runoff simulation was carried-out in three selected sub-basins of Lower River Niger Basin based on observable discharge dataset. Related error estimation was carried-out to estimate the runoff simulation uncertainty while model optimization approach entails use of Rosenbrock-Simplex method and model reliability evaluation entails the use of Nash and Sutcliffe efficiency criteria methods. Result shows a satisfactory model performance at Baro and Makurdi gauging stations （savannah ecological zone） while under-estimation characterizes simulated flow at Onitsha gauging station（Forest ecological region）. Seasonally, the model best fit the dry season flow but underestimate during the high flow periods （rainy seasons and wetter years）.

Effects of a sex ratio gradient on female mate-copying and choosiness in Drosophila melanogaster

In many sexually reproducing species, individuals can gather information about potential mates by observing their mating success. This behavioral pattern, that we call mate-copying, was reported in the fruit fly Drosophila rnelanogaster where females choosing between 2 males of contrasting phenotypes can build a preference for males of the phenotype they previously saw being chosen by a demonstrator female. As sex ratio is known to affect mate choice, our goal was to test whether mate-copying is also affected by encountered sex ratios. Thus, we created a gradient of sex ratio during demonstrations of mate-copying experiments by changing the number of females observ- ing from a central arena 6 simultaneous demonstrations unfolding in 6 peripheral compartments of a hexagonal device. We also tested whether the sex ratio experienced by females during demon- strations affected their choosiness （male courtship duration and double courtship rate） in subse- quent mate-choice tests. Experimental male：female sex ratio during demonstrations did not affect mate-copying indices, but positively affected the proportion of both males courting the female during mate-choice tests, as well as male courtship duration, the latter potentially explaining the for- mer relationship. As expected, the sex ratio affected female choosiness positively, and Drosophila females seem to have evolved a mate-copying ability independently of sex ratio, and a capacity to adapt their choosiness to male availability. This suggests that, as in many animal species, individuals, especially females, can adapt their mate choice depending on the current sex ratio.

Report of the first international workshop on onchocerciasis-associated epilepsy

Background:Recently,several epidemiological studies performed in Onchocerca volvulus-endemic regions have suggested that onchocerciasis-associated epilepsy(OAE)may constitute an important but neglected public health problem in many countries where onchocerciasis is still endemic.Main text:On October 12-14th 2017,the first international workshop on onchocerciasis-associated epilepsy(OAE)was held in Antwerp,Belgium.The workshop was attended by 79 participants from 20 different countries.Recent research findings strongly suggest that O.volvulus is an important contributor to epilepsy,particularly in meso-and hyperendemic areas for onchocerciasis.Infection with O.volvulus is associated with a spectrum of epileptic seizures,mainly generalised tonic-clonic seizures but also atonic neck seizures(nodding),and stunted growth.OAE is characterised by an onset of seizures between the ages of 3-18 years.Multidisciplinary working groups discussed topics such as how to 1)strengthen the evidence for an association between onchocerciasis and epilepsy,2)determine the burden of disease caused by OAE,3)prevent OAE,4)improve the treatment/care for persons with OAE and affected families,5)identify the pathophysiological mechanism of OAE,and 6)deal with misconceptions,stigma,discrimination and gender violence associated with OAE.An OAE Alliance was created to increase awareness about OAE and its public health importance,stimulate research and disseminate research findings,and create partnerships between OAE researchers,communities,advocacy groups,ministries of health,non-governmental organisations,the pharmaceutical industry and funding organizations.Conclusions:Although the exact pathophysiological mechanism underlying OAE remains unknown,there is increasing evidence that by controlling and eliminating onchocerciasis,OAE will also disappear.Therefore,OAE constitutes an additional argument for strengthening onchocerciasis elimination efforts.Given the high numbers of people with epilepsy in O.volvulus-endemic regions,more advocacy is urgently needed to provide anti-epileptic treatment to improve the quality of life of these individuals and their families.

ISOLATION AND CHARACTERIZATION OF BIOACTIVE COMPOUNDS FROM ENDOPHYTES ASSOCIATED WITH MEDICINAL PLANTS

In the field of natural products,plants have proven their interest as a source of lead compounds in drug discovery.Nevertheless,in the context of biodiversity preservation,researchers recently focused their work on renewable sources,like micromycetes,which present the ability to modulate their metabolism depending on the substrate.Fungi are one of nature’s most promising source for