Genetic diversity of cassava (Manihot esculanta crantz) germplasm and effect of environment on resistance to Cassava Brown Streak and Cassava Mosaic Diseases in Burundi

IITA supervisor: Dr. Tumwegamire, S.Cassava is an important cash crop for many small scale farmers in Burundi. Most small scale farmers use local landraces and though they have farmer preferred traits, their genetic diversity is unknown and marred by phenotypic susceptibility to Cassava Brown Streak Disease (CBSD) and Cassava Mosaic Disease (CMD). This limits future breeding programs to improve cassava production and resistance to diseases in Burundi. Due to this, disease tolerant genotypes from other countries were introduced to Burundi to help improve on their germplasm and then determine the relationships between local landraces and improved germplasm. Objectives of this study were to (1) assess the genetic diversity among cassava landraces and introduced cassava genotypes using morphological and molecular markers, (2) determine effects of genotype by environment (GxE) interaction on resistance to CBSD and CMD diseases in varied agro-ecological zones of Burundi. Genotype characterization was done using 17 qualitative agro morphological traits while molelcular analysis was conducted using SNP genotyping data from DaRTseq using KDCompute on 118 genotypes. For objective 2, the effect of GxE interaction on resistance to cassava viral diseases was determined using 18 accessions arranged in alpha lattice design on 9 blocks per site. Data was taken on sprouted cuttings, whiteflies population, foliar diseases, root necrosis, growth parameters and yield. Results for objective 1, on 118 accessions revealed more than 18,000 SNPs but there with low genetic distance (Fst<0.15) between local landraces and resistant genotypes. Phenotypic classification showed three main clusters based on Ward’s Method with cluster III containing all introduced genotypes; genotypic classification showed six main clusters with cluster II and IV having 5 and 11 introduced genotypes, respectively. Overall, 73 accessions had unique genotypes while 16 accessions were genetic clones indicating that 73 could be used in hybridization programs. Morphological markers showed five paired accessions using Ward’s method. According to the field experimental study, 3 genotypes had dual tolerance to CBSD and CMD on leaves; 5 genotypes were tolerant to CMD; 7 genotypes were tolerant to CBSD on leaves and stems while 2 genotypes were resistant. Overall, 8 clones showed high yield while 3 were tolerant to CMD and CBSD in all locations indicating that they could be used in breeding programs for germplasm improvement. In conclusion, results on molecular characterization will contribute to optimizing the conservation of genetic resources, together with understanding diversity and its use in crop improvement. Identification of resistant/ tolerant genotypes will be incorporated in cassava breeding program for transferring the genes to farmer-preferred varieties. Dually resistant genotypes like Mkumba and Pwani were identified as putative duplicates clones, might be used as genetic stock that could combine resistance to CBSD and CMD a single genotype. From this study, it is recommended that these cassava genotypes could be included in Burundi genetic improvement programs for higher yield to realize genetic gains with time

Radioluminescence of annealed synthetic quartz

The radioluminescence of synthetic quartz annealed at various temperatures up to 1000 °C is reported. The amplitude of the emission bands increases with annealing temperature. In addition, when samples are annealed at temperatures exceeding 700 °C, the intensity of the radioluminescence increases with duration of annealing. The corresponding emission spectra show seven emission bands at 2.04, 2.54, 2.77, 3.04, 3.40, 3.75 and 3.91 eV. The change in dominant emission band with annealing is consistent with annealing-induced variations in lifetimes determined previously from time-resolved optically stimulated luminescence spectra in the same samples

Multiscale finite element modeling of nonlinear magnetoquasistatic problems using magnetic induction conforming formulations

© 2018 Society for Industrial and Applied Mathematics. In this paper we develop magnetic induction conforming multiscale formulations for magnetoquasistatic problems involving periodic materials. The formulations are derived using the periodic homogenization theory and applied within a heterogeneous multiscale approach. Therefore the fine-scale problem is replaced by a macroscale problem defined on a coarse mesh that covers the entire domain and many mesoscale problems defined on finely-meshed small areas around some points of interest of the macroscale mesh (e.g., numerical quadrature points). The exchange of information between these macro and meso problems is thoroughly explained in this paper. For the sake of validation, we consider a two-dimensional geometry of an idealized periodic soft magnetic composite.status: publishe

Complement receptor CD46 co-stimulates optimal human CD8+ T cell effector function via fatty acid metabolism

The induction of human CD4+ Th1 cells requires autocrine stimulation of the complement receptor CD46 in direct crosstalk with a CD4+ T cell-intrinsic NLRP3 inflammasome. However, it is unclear whether human cytotoxic CD8+ T cell (CTL) responses also rely on an intrinsic complement-inflammasome axis. Here we show, using CTLs from patients with CD46 deficiency or with constitutively-active NLRP3, that CD46 delivers co-stimulatory signals for optimal CTL activity by augmenting nutrient-influx and fatty acid synthesis. Surprisingly, although CTLs express NLRP3, a canonical NLRP3 inflammasome is not required for normal human CTL activity, as CTLs from patients with hyperactive NLRP3 activity function normally. These findings establish autocrine complement and CD46 activity as integral components of normal human CTL biology, and, since CD46 is only present in humans, emphasize the divergent roles of innate immune sensors between mice and men

Socioeconomic inequalities in prostate cancer screening in low- and middle-income countries: an analysis of the demographic and health surveys between 2010 and 2019

Introduction: Prostate cancer screening is a valuable public health tool in the early detection of prostate cancer. In this study, we aimed to determine the socioeconomic inequalities in the coverage of prostate cancer screening in Low and Middle-Income Countries (LMICs). Methods: This was a retrospective analysis of men's recode data files that were collected by the Demographic and Health Surveys (DHS) in LMICs (Armenia, Colombia, Honduras, Kenya, Namibia, Dominican Republic, and the Philippines). We included surveys that were conducted from 2010 to 2020 and measured the coverage of prostate cancer screening and the study population was men aged 40 years or older. Socioeconomic inequality was measured using the Concertation Index (CIX) and the Slope Index of Inequality (SII). Results: Eight surveys from seven countries were included in the study with a total of 47,863 men. The coverage of prostate cancer screening was below 50% in all the countries with lower rates in the rural areas compared to the urban areas. The pooled estimate for the coverage of screening was 10.4% [95% CI, 7.9–12.9%). Inequalities in the coverage of prostate cancer screening between the wealth quintiles were observed in the Democratic Republic, Honduras, and Namibia. Great variation in inequalities in the coverage of prostate cancer screening between rural and urban residents was observed in Colombia and Namibia. Conclusion: The coverage of prostate cancer screening was low in LMICs with variations in the coverage by the quintile of wealth (pro-rich) and type of place of residence (pro-urban). Policy summary: To achieve the desired impact of prostate cancer screening services in LMICs, it is important that the coverage of screening programs targets men living in rural areas and those in low wealth quintiles

Estimates of disease burden caused by foodborne pathogens in contaminated dairy products in Rwanda

Abstract Background The Girinka program in Rwanda has contributed to an increase in milk production, as well as to reduced malnutrition and increased incomes. But dairy products can be hazardous to health, potentially transmitting diseases such as bovine brucellosis, tuberculosis, and cause diarrhea. We analyzed the burden of foodborne disease due to consumption of raw milk and other dairy products in Rwanda to support the development of policy options for the improvement of the quality and safety of milk. Methods Disease burden data for five pathogens (Campylobacter spp., nontyphoidal Salmonella enterica, Cryptosporidium spp., Brucella spp., and Mycobacterium bovis) were extracted from the 2010 WHO Foodborne Disease Burden Epidemiology Reference Group (FERG) database and merged with data of the proportion of foodborne disease attributable to consuming dairy products from FERG and a separately published Structured Expert Elicitation study to generate estimates of the uncertainty distributions of the disease burden by Monte Carlo simulation. Results According to WHO, the foodborne disease burden (all foods) of these five pathogens in Rwanda in 2010 was like or lower than in the Africa E subregion as defined by FERG. There were 57,500 illnesses occurring in Rwanda owing to consumption of dairy products, 55 deaths and 3,870 Disability Adjusted Life Years (DALYs) causing a cost-of-illness of $3.2 million. 44% of the burden (in DALYs) was attributed to drinking raw milk and sizeable proportions were also attributed to traditionally (16–23%) or industrially (6–22%) fermented milk. More recent data are not available, but the burden (in DALYs) of tuberculosis and diarrheal disease by all causes in Rwanda has declined between 2010 and 2019 by 33% and 46%, respectively. Conclusion This is the first study examining the WHO estimates of the burden of foodborne disease on a national level in Rwanda. Transitioning from consuming raw to processed milk (fermented, heat treated or otherwise) may prevent a considerable disease burden and cost-of-illness, but the full benefits will only be achieved if there is a simultaneous improvement of pathogen inactivation during processing, and prevention of recontamination of processed products