Performance and inheritance of yield and maize streak virus disease resistance in white maize and yellow conversions

In sub Saharan Africa, past effort has registered success in developing high yielding and foliar disease resistant maize ( Zea mays L.) varieties, which are deficient in pro-vitamin A. A new initiative is to develop maize varieties, tolerant to foliar diseases and rich in pro-vitamin A carotenoids. To achieve this, yellow conversions of white testers and other elite maize varieties have been developed by the International Center for Maize and Wheat Development (CIMMYT). Unlike the white lines, limited information on agronomic performance and disease resistance is available for yellow maize conversions. This study was conducted to evaluate the performance of white maize and their corresponding yellow maize conversions for yield and tolerance to Maize streak virus (MSV) disease; and determine the inheritance patterns of these traits. Fourty seven three-way hybrids generated in a Line by tester mating design (North Carolina 2), 12 inbred lines (used as male parents), 4 single crosses (used as female parents) and 3 commercials checks were screened for resistance to Maize streak virus (MSV) disease at the National Crop Resources Research Institute (NaCRRI) in Uganda. The same genotypes were evaluated in a 9x5 alpha lattice design in three locations of Uganda (National Crop Resources Research Institute (NACRRI), National Semi Arid Resources Research Institute (NaSARRI) and Bulambuli) for agronomic performance. Results confirmed tolerance to MSV in testers CML202, CML395, CML444, CML445 and CML312-SR (white). Genotypes performed significantly differently for yield, anthesis days, plant height, ear height, husk cover, grain texture, reaction to Gray leaf spot (GLS) (P<0.001) and ear aspect (P<0.01). However, pairwise comparison of white and yellow conversions indicated no significant difference (P>0.05) in agronomic performance and tolerance to diseases. General combining ability (GCA) was more important than specific combining ability (SCA) for most traits, except for anthesis days, Turcicum leaf blight (TLB), GLS and yield. GCA effects for yield were not significant in both lines (male parents) and single cross testers (female parents) of white and yellow conversions. However, two unique cases were observed for diseases; yellow conversion of line CML444 significantly combined for susceptibility to TLB; while tester CML312/CML442 combined for resistance to GLS. Additionally, there was low heritably estimates for tolerance to MSV and yield. Generally, there was no significant difference between white and corresponding yellow maize conversion, implying that there is no significant loss in MSV resistance and yield performance while converting white into yellow maize.En Afrique sub-Saharienne, les efforts ant\ue9rieurs ont connu de grands succ\ue8s dans le d\ue9veloppement des vari\ue9t\ue9s tr\ue8s productives et tol\ue9rantes aux maladies foliaires du ma\uefs ( Zea mays L.), mais qui sont pauvres en provitamine A. La nouvelle vision est de d\ue9velopper des vari\ue9t\ue9s de ma\uefs r\ue9sistantes aux principales maladies foliaires, et riche en carot\ue9no\uefdes provitamine A. Pour y arriver, les conversions jaunes issues des testeurs blancs de ma\uefs ainsi que les vari\ue9t\ue9s \ue9lite ont \ue9t\ue9 d\ue9velopp\ue9es par le Centre International pour l\u2019Am\ue9lioration du Ma\uefs et du Bl\ue9 (CIMMYT). Contrairement aux lign\ue9es blanches de ma\uefs, la performance agronomique et le niveau de r\ue9sistance aux maladies des lign\ue9es jaunes reste m\ue9connue. Cette \ue9tude a \ue9t\ue9 men\ue9e dans le but d\u2019\ue9valuer la performance au niveau du rendement et la r\ue9sistance \ue0 la maladie des bandes (MSV) des vari\ue9t\ue9s de ma\uefs \ue0 grain de couleur blanche et leurs conversions de couleur jaune et d\ue9terminer le mode d\u2019h\ue9ritabilit\ue9 de ces deux param\ue8tres \ue9tudi\ue9s. Quarante-sept hybrides trois voies produits dans un mode de croisement Lign\ue9e par testeur (North Carolina II), 12 lign\ue9es \ue9pur\ue9es (utilis\ue9es comme parents m\ue2les), 4 hybrides simples (utilis\ue9s comme parents femelles) et 3 t\ue9moins ont \ue9t\ue9 inocul\ue9s par l\u2019agent causal de la maladie des bandes \ue0 NaCRRI (National Crop Ressources Research Institute) en Ouganda. La performance agronomique des m\ueames g\ue9notypes a \ue9t\ue9 \ue9valu\ue9e dans un dispositif exp\ue9rimental d\u2019alpha lattice (5parcelles \ue9l\ue9mentaires x 9 blocks) dans 3 sites de l\u2019Ouganda \ue0 savoir NaCRRI (National Crop Ressources Research Institute), NaSARRI (National Semi Arid Resources Research Institute) et Bulambuli. Les r\ue9sultats ont confirm\ue9 la tol\ue9rance \ue0 la MSV des testeurs \ue0 grains blancs CML202, CML395, CML444, CML445 et CML 312-SR. La performance des g\ue9notypes \ue9tait hautement significativement diff\ue9rente pour le rendement, le nombre de jours de floraison m\ue2le, la hauteur des plants, le niveau d\u2019insertion des \ue9pis sur les plants, la couverture des \ue9pis par les spathes, la texture des grains, la r\ue9action \ue0 la GLS (Glay leaf spot) (P<0.001) ainsi que pour l\u2019aspect des \ue9pis (P<0.01). Cependant, la comparaison entre le ma\uefs blanc et sa conversion jaune a montr\ue9 une diff\ue9rence non significative (P>0.05) au niveau de leur performance agronomique et la tol\ue9rance aux maladies. L\u2019aptitude g\ue9n\ue9rale \ue0 la combinaison (GCA) \ue9tait plus importante que l\u2019aptitude sp\ue9cifique \ue0 la combinaison (SCA) pour la plupart des param\ue8tres \ue0 l\u2019exception du nombre de jours \ue0 floraison m\ue2le, la tol\ue9rance \ue0 l\u2019helminthosporiose (TLB), GLS et le rendement. Les effets dus \ue0 la GCA pour le rendement n\u2019\ue9taient pas significatifs pour les parents m\ue2les (lign\ue9es) et femelles (hybrides simples) des g\ue9notypes \ue0 grain de couleur blanche et leurs conversions \ue0 grain de couleur jaune. N\ue9anmoins, deux cas exceptionnels ont \ue9t\ue9 observ\ue9s pour la tol\ue9rance aux maladies: la conversion jaune de la lign\ue9e CML444 \ue9tait un mauvais combinateur pour la TLB, alors que le testeur CML312/CML442 combinait bien pour la tol\ue9rance \ue0 la GLS. En plus, l\u2019h\ue9ritabilit\ue9 \ue9tait faible pour la tol\ue9rance \ue0 la MSV et le rendement. En g\ue9n\ue9ral, il n\u2019y avait pas de diff\ue9rence significative entre les g\ue9notypes \ue0 grain blanc et leurs conversions jaunes respectives, ce qui signifie que, lors de la conversion des vari\ue9t\ue9s \ue0 grain blanc en vari\ue9t\ue9s \ue0 grain jaune, il n\u2019y a aucune perte significative en ce qui est de la tol\ue9rance \ue0 la MSV et la performance en rendement des grains

The virological durability of first-line ART among HIV-positive adult patients in resource limited settings without virological monitoring: a retrospective analysis of DART trial data

BACKGROUND: Few low-income countries have virological monitoring widely available. We estimated the virological durability of first-line antiretroviral therapy (ART) after five years of follow-up among adult Ugandan and Zimbabwean patients in the DART study, in which virological assays were conducted retrospectively. METHODS: DART compared clinically driven monitoring with/without routine CD4 measurement. Annual plasma viral load was measured on 1,762 patients. Analytical weights were calculated based on the inverse probability of sampling. Time to virological failure, defined as the first viral load measurement ≥200 copies/mL after 48 weeks of ART, was analysed using Kaplan-Meier plots and Cox regression models. RESULTS: Overall, 65% of DART trial patients were female. Patients initiated first-line ART at a median (interquartile range; IQR) age of 37 (32-42) and with a median CD4 cell count of 86 (32-140). After 240 weeks of ART, patients initiating dual-class nucleoside reverse-transcriptase inhibitor (NRTI) -non-nucleoside reverse-transcriptase (NNRTI) regimens containing nevirapine + zidovudine + lamivudine had a lower incidence of virological failure than patients on triple-NRTI regimens containing tenofovir + zidovudine + lamivudine (21% vs 40%; hazard ratio (HR) =0.48, 95% CI:0.38-0.62; p < 0.0001). In multivariate analyses, female patients (HR = 0.79, 95% CI: 0.65-0.95; p = 0.02), older patients (HR = 0.73 per 10 years, 95% CI: 0.64-0.84; p < 0.0001) and patients with a higher pre-ART CD4 cell count (HR = 0.64 per 100 cells/mm(3), 95% CI: 0.54-0.75; p < 0.0001) had a lower incidence of virological failure after adjusting for adherence to ART. No difference in failure rate between the two randomised monitoring strategies was observed (p= 0.25). CONCLUSIONS: The long-term durability of virological suppression on dual-class NRTI-NNRTI first-line ART without virological monitoring is remarkable and is enabled by high-quality clinical management and a consistent drug supply. To achieve higher rates of virological suppression viral-load-informed differentiated care may be required. TRIAL REGISTRATION: Prospectively registered on 18/10/2000 as ISRCTN13968779

On Detection of Sybil Attack in Large-Scale VANETs Using Spider-Monkey Technique

Sybil security threat in vehicular ad hoc networks (VANETs) has attracted much attention in recent times. The attacker introduces malicious nodes with multiple identities. As the roadside unit fails to synchronize its clock with legitimate vehicles, unintended vehicles are identified, and therefore erroneous messages will be sent to them. This paper proposes a novel biologically inspired spider-monkey time synchronization technique for large-scale VANETs to boost packet delivery time synchronization at minimized energy consumption. The proposed technique is based on the metaheuristic stimulated framework approach by the natural spider-monkey behavior. An artificial spider-monkey technique is used to examine the Sybil attacking strategies on VANETs to predict the number of vehicular collisions in a densely deployed challenge zone. Furthermore, this paper proposes the pseudocode algorithm randomly distributed for energy-efficient time synchronization in two-way packet delivery scenarios to evaluate the clock offset and the propagation delay in transmitting the packet beacon message to destination vehicles correctly. The performances of the proposed technique are compared with existing protocols. It performs better over long transmission distances for the detection of Sybil in dynamic VANETs' system in terms of measurement precision, intrusion detection rate, and energy efficiency

Phenotypic and genotypic analyses to guide selection of reverse transcriptase inhibitors in second-line HIV therapy following extended virological failure in Uganda

Objectives We investigated phenotypic and genotypic resistance after 2 years of first-line therapy with two HIV treatment regimens in the absence of virological monitoring. Methods NORA [Nevirapine OR Abacavir study, a sub-study of the Development of AntiRetroviral Therapy in Africa (DART) trial] randomized 600 symptomatic HIV-infected Ugandan adults (CD4 cell count <200 cells/mm3) to receive zidovudine/lamivudine plus abacavir (cABC arm) or nevirapine (cNVP arm). All virological tests were performed retrospectively, including resistance tests on week 96 plasma samples with HIV RNA levels ≥1000 copies/mL. Phenotypic resistance was expressed as fold-change in IC50 (FC) relative to wild-type virus. Results HIV-1 RNA viral load ≥1000 copies/mL at week 96 was seen in 58/204 (28.4%) cABC participants and 21/159 (13.2%) cNVP participants. Resistance results were available in 35 cABC and 17 cNVP participants; 31 (89%) cABC and 16 (94%) cNVP isolates had a week 96 FC below the biological cut-off for tenofovir (2.2). In the cNVP arm, 16/17 participants had resistance mutations synonymous with high-level resistance to nevirapine and efavirenz; FC values for etravirine were above the biological cut-off in 9 (53%) isolates. In multivariate regression models, K65R, Y115F and the presence of thymidine analogue-associated mutations were associated with increased susceptibility to etravirine in the cABC arm. Conclusions Our data support the use of tenofovir following failure of a first-line zidovudine-containing regimen and shed further light on non-nucleoside reverse transcriptase inhibitor hypersusceptibility

Assessment of aflatoxin and fumonisin contamination levels in maize and mycotoxins awareness and risk factors in Rwanda

Mycotoxins are secondary metabolites of fungi that are toxic to humans and animals when consumed in contaminated food and feed. The Rwandan climate conditions like steady temperature and sufficient rainfall favor the growth of fungi leading to high probability of mycotoxins contamination. Mycotoxins get into maize throughout the value chain from the field to processed products. Maize is&nbsp; promoted in Rwanda under the Crop Intensification Program (CIP), for nutrition and food security. The aim of the study was to evaluate mycotoxins (Aflatoxin and fumonisin) levels in maize and assess awareness and factors associated with mycotoxin contamination in Rwanda. Maize samples (227 kg) from season B 2019 were collected in 15 Districts in five provinces of Rwanda after an interview with a representative of the household or cooperative using a structured questionnaire. The samples were analyzed for aflatoxin and&nbsp; fumonisin using Reveal Q+ and AccuScan Gold Reader. From the interview, most of the respondents were not aware about aflatoxin (59.7 %) and 99 % did not know the effect of mycotoxins on human health. The average of aflatoxin contamination in surveyed districts was 6.69±13 μg/kg. In general, 90.4 % of samples scored below the limit of aflatoxin level regulated in East Africa/Kenya regulation standards (10 μg/kg). The levels of aflatoxin ranged between 0 and 100.9 μg/kg. The means aflatoxin levels within districts ranged between 1.36±0.5 μg/kg and 13.75±25 μg/kg. Among 9.6 % of the samples containing aflatoxins above the EU and Kenyan regulations standard limit, 5.7 % were above the US standards of 20 μg/kg. Within clusters, the level of aflatoxin more than 10 μg/kg was 5 %, 7 % and 18 % for stores, household and market samples, respectively. From the study, as mechanical damage of grains, moisture content of grains and the temperature of the store house increased, Aflatoxin level also increased. Fumonisin analyzed in maize ranged from 0 to 2.3 μg/g and only one sample from market showed a slightly higher level of fumonisin than the EU and US limit of 2 μg/g. More effort for aflatoxin mitigation is needed at the market level. Farmers need to be aware and taught how they can improve their agricultural system and more knowledge on mycotoxin control is needed. The results point to appropriate measures to recommend for control ofmycotoxins in Rwanda and awareness creation. Key words: AccuScan, Aflatoxin, Fumonisin, Fungal, Maize, Mycotoxins, Reveal Q+, Rwand

Longitudinal evaluation of aflatoxin exposure in two cohorts in south-western Uganda

Aflatoxins (AF) are a group of mycotoxins. AF exposure causes acute and chronic adverse health effects such as aflatoxicosis and hepatocellular carcinoma in human populations, especially in the developing world. In this study, AF exposure was evaluated using archived serum samples from human immunodeficiency virus (HIV)-seronegative participants from two cohort studies in south-western Uganda. AFB1-lysine (AFB-Lys) adduct levels were determined via HPLC fluorescence in a total of 713 serum samples from the General Population Cohort (GPC), covering eight time periods between 1989 and 2010. Overall, 90% (642/713) of the samples were positive for AFB-Lys and the median level was 1.58 pg mg(-1) albumin (range = 0.40-168 pg mg(-1) albumin). AFB-Lys adduct levels were also measured in a total of 374 serum samples from the Rakai Community Cohort Study (RCCS), across four time periods between 1999 and 2003. The averaged detection rate was 92.5% (346/374) and the median level was 1.18 pg mg(-1) albumin (range = 0.40-122.5 pg mg(-1) albumin). In the GPC study there were no statistically significant differences between demographic parameters, such as age, sex and level of education, and levels of serum AFB-Lys adduct. In the RCCS study, longitudinal analysis using generalised estimating equations revealed significant differences between the adduct levels and residential areas (p = 0.05) and occupations (p = 0.02). This study indicates that AF exposure in people in two populations in south-western Uganda is persistent and has not significantly changed over time. Data from one study, but not the other, indicated that agriculture workers and rural area residents had more AF exposure than those non-agricultural workers and non-rural area residents. These results suggest the need for further study of AF-induced human adverse health effects, especially the predominant diseases in the region

Evaluation of equity in informal land development systems in two Nigerian cities

The informal land development system in Sub-Saharan Africa (SSA) is perceived to promote equity and could be leveraged to support sustainable urban development and management. However, scanty empirical evidence exists on the extent of the system’s provision of equity to support policy formulation and practice in the region. Based on stakeholder workshops, focus group discussions and questionnaire surveys, this study analyses the system’s provision of equity in Nigeria. The study finds all categories of people undertake informal developments. Consistent with literature, this finding reflects wide patronage of the informal land development system and its relevance. Nevertheless, contrary to the existing perception, the system’s provision of equity is low. The study recommends for the institution of pro-poor and gender sensitive land development and management policies and programmes to increase the levels of equity to support the achievement of the country’s sustainable urban development and management agenda

The Role of Climate Variability in the Spread of Malaria in Bangladeshi Highlands

Malaria is a major public health problem in Bangladesh, frequently occurring as epidemics since the 1990s. Many factors affect increases in malaria cases, including changes in land use, drug resistance, malaria control programs, socioeconomic issues, and climatic factors. No study has examined the relationship between malaria epidemics and climatic factors in Bangladesh. Here, we investigate the relationship between climatic parameters [rainfall, temperature, humidity, sea surface temperature (SST), El Niño-Southern Oscillation (ENSO), the normalized difference vegetation index (NDVI)], and malaria cases over the last 20 years in the malaria endemic district of Chittagong Hill Tracts (CHT)

Taxation and political stability

The present study is, in particular, an attempt to test the relationship between tax level and political stability by using some economic control variables and to see the relationship among government effectiveness, corruption, and GDP. For the purpose, we used the GMM (1991) and GMM system (1998), using a country-level panel data from 112 countries for the period 1997 to 2010. The main results show that political stability is not the key for the tax policy, under the control of political regime durability the taxes as percent in GDP having consistent sinusoidal tendency, by cubic type