Hierarchical Neural Networks, p-Adic PDEs, and Applications to Image Processing

The first goal of this article is to introduce a new type of p-adic reaction-diffusion cellular neural network with delay. We study the stability of these networks and provide numerical simulations of their responses. The second goal is to provide a quick review of the state of the art of p-adic cellular neural networks and their applications to image processing

Grain yield response of Fonio (Digitaria exilis) varieties to fertilizer and cost- effectiveness under two different production systems in the Gambia

Fonio is an easy crop to grow because it grows well even on poor sandy soils, as well as in areas with low rainfall. The crop can withstand long dry  spells during the production season which are becoming a common occurrence in the West African subregion. In The Gambia, the common name  for the crop is “Findi”. It is commonly grown in fields that were previously cultivated with groundnut. Fonio is one of the oldest cereal crops grown in  the country; however, its cultivation has drastically declined to the extent that it is currently considered a minor crop in the country. Fonio is a very  fast-growing crop and matures earlier than most cereals. Its ability to withstand dry spells and its high nutritive value makes it an ideal climate-  smart crop. For this reason, there is renewed momentum in promoting the crop in the country. Despite these renewed efforts in its promotion,  there still exists a huge gap in terms of information on improved production practices that could help uplift the existing low yields. Appropriate  agronomic practices that can boost fonio productivity are not well documented at national level. To gather information on the input requirements  and utilizations, adaptability and productivity of fonio in The Gambia, experiments were conducted in 2018 and 2019 with the aim of generating  important production information that could guide efficient production and enhance productivity. Results obtained showed that fonio responded  positively to application of fertilizer. Application of 100 kg ha -1 comprising half NPK (15-15-15) and half urea was sufficient to produce financially  beneficial yields. Results also indicated that “Findiba”, which is a landrace may not be suitable for cultivation anymore due to its long growth period  amidst the short and erratic nature of the rainfall. The Momo and the Momosato varieties which are of shorter durations and high-yielding are more  suitable in the existing climatic conditions of the country

Diffusion and adoption of new rice varieties for Africa (Nerica) in the Gambia

Rice ( Oryza sativa ) is one of the most important cereal crops cultivated in sub-Saharan Africa (SSA). It is ranked as the fourth most important crop in terms of production after sorghum ( Sorghum bicolor ), maize ( Zea mays ) and millet ( Eleusine coracana ). The objective of this study was to establish adoption rates, and their determinants, of the New Rice Varieties for Africa (NERICA) in the Gambia. We used data from a stratified sample of 600 rice farmers and applied the Average Treatment Estimation (ATE) framework to establish rate of adoption and associated factors. The results revealed that NERICA adoption rate was barely 40% falling far below the expected 83%. The shortfall was due to the incomplete stakeholder exposure to NERICA in the period before 2006. The introduction of NERICA to villages was found to be a significant determinant of both exposure and adoption of NERICA varieties.Le riz ( Oryza sativa ) est l\u2019une des c\ue9r\ue9als les plus cultiv\ue9es en Afrique Sub-Saharienne. Il est la quatri\ue8me culture la plus importante en terme de production apr\ue8s le sorgho ( Sorghum bicolor ), le ma\uefs ( Zea mays ) et le millet ( Eleusine coracana ). L\u2019objectif de cette \ue9tude \ue9tait de \ue9tablir les taux d\u2019adoption et d\ue9terminants de nouvelles vari\ue9t\ue9s pour l\u2019Afrique (NERICA) en Gambie. Nous avons utilis\ue9 des donn\ue9es issues d\u2019un \ue9chantillon stratifi\ue9 de 600 riziculteurs, et le mod\ue8le d\u2019Estimation de la Moyenne de Traitements (ATE) \ue9tait appliqu\ue9 pour \ue9tablir le taux d\u2019adoption et les facteurs associ\ue9s. Les r\ue9sultats ont r\ue9v\ue9l\ue9 que le taux d\u2019adotpion du NERICA \ue9tait d\u2019environ 40% ce qui est en contraste avec le taux esp\ue9r\ue9 de 83%. Cette baisse \ue9tait due \ue0 une imparfaite pr\ue9sentation du NERICA aux partenaires avant l\u2019ann\ue9e 2006. L\u2019introduction du NERICA aux villages \ue9tait un d\ue9terminant significatif de la pr\ue9sentation et l\u2019adoption des vari\ue9t\ue9s NERICA

Facility and community results-based financing to improve maternal and child nutrition and health in The Gambia

In 2013, the Government of The Gambia implemented a novel results-based financing (RBF) intervention designed to improve maternal and child nutrition and health through a combination of community, facility and individual incentives. In a mixed-methods study, we used a randomized 2 x 2 study design to measure these interventions' impact on the uptake of priority maternal health services, hygiene and sanitation. Conditional cash transfers to individuals were bundled with facility results-based payments. Community groups received incentive payments conditional on completion of locally-designed health projects. Randomization occurred separately at health facility and community levels. Our model pools baseline, midline and endline exposure data to identify evidence of the interventions' impact in isolation or combination. Multivariable linear regression models were estimated. A qualitative study was embedded, with data thematically analyzed. We analyzed 5,927 household surveys: 1,939 baseline, 1,951 midline, and 2,037 endline. On average, community group interventions increased skilled deliveries by 11 percentage points, while the facility interventions package increased them by seven percentage points. No impact was found, either in the community group or facility intervention package arms on early ANC. The community group intervention led to 49, 43 and 48 percentage point increases in handwashing stations, soaps at station and water at station, respectively. No impact was found on improved sanitation facilities. The qualitative data help understand factors underlying these changes. No interaction was found between the community and facility interventions. Where demand-side barriers predominate and community governance structures exist, community group RBF interventions may be more effective than facility designs

Quantitative determination of vitamin D metabolites in plasma using UHPLC-MS/MS

Vitamin D is an important determinant of bone health at all ages. The plasma concentrations of 25-hydroxy vitamin D (25-OH D) and other metabolites are used as biomarkers for vitamin sufficiency and function. To allow for the simultaneous determination of five vitamin D metabolites, 25-OH D3, 25-OH D2, 24,25-(OH)2 D3, 1,25-(OH)2 D3, and 1,25-(OH)2 D2, in low volumes of human plasma, an assay using ultra-high-performance liquid chromatography–tandem mass spectrometry (UHPLC-MS/MS) was established. Plasma samples were spiked with isotope-labeled internal standards and pretreated using protein precipitation, solid-phase extraction (SPE) and a Diels–Alder derivatization step with 4-phenyl-1,2,4-triazoline-3,5-dione. The SPE recovery rates ranged from 55% to 85%, depending on the vitamin D metabolite; the total sample run time was <5 min. Mass spectrometry was conducted using positive ion electrospray ionization in the multiple reaction monitoring mode on a quadrupole–quadrupole-linear ion trap instrument after pre-column addition of methylamine to increase the ionization efficiency. The intra- and inter-day relative standard deviations were 1.6–4.1% and 3.7–6.8%, respectively. The limit of quantitation for these compounds was determined to be between 10 and 20 pg/mL. The 25-OH D results were compared with values obtained for reference materials (DEQAS). In addition, plasma samples were analyzed with two additional Diasorin antibody assays. All comparisons with conventional methods showed excellent correlations (r2 = 0.9738) for DEQAS samples, demonstrating the high degree of comparability of the new UHPLC-MS/MS technique to existing methods

Vitamin D Deficiency and Its Health Consequences in Africa

Africa is heterogeneous in latitude, geography, climate, food availability, religious and cultural practices, and skin pigmentation. It is expected, therefore, that prevalence of vitamin D deficiency varies widely, in line with influences on skin exposure to UVB sunshine. Furthermore, low calcium intakes and heavy burden of infectious disease common in many countries may increase vitamin D utilization and turnover. Studies of plasma 25OHD concentration indicate a spectrum from clinical deficiency to values at the high end of the physiological range; however, data are limited. Representative studies of status in different countries, using comparable analytical techniques, and of relationships between vitamin D status and risk of infectious and chronic diseases relevant to the African context are needed. Public health measures to secure vitamin D adequacy cannot encompass the whole continent and need to be developed locally