106 research outputs found

    RESPONSE OF MAIZE TO PLANTING DENSITIES AND INCORPORATION METHODS OF PRECEDING COWPEA GREEN MANURE IN A DERIVED SAVANNAH ECOLOGY OF NIGERIA

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    A field trial was conducted in the University of Agriculture, Abeokuta, a derived savannah ecological zone of Nigeria, between April to September, 2009 and March to August, 2010 to evaluate the response of succeeding maize to planting density and application methods of preceding cowpea green manure.  The green manure was established in a 2 × 3 factorial experiment arranged in a Randomized Complete Block design RCBD. There were three populations densities/ha of cowpea: 30cm×60cm(55,555), 30cm×30cm(111,111) and 30cm×15cm(222,222) and either incorporated or left as mulched six weeks after planting. One week after, maize variety, SUWAN1-SR was planted on all plots and a control plot. Biomass from population densities of 111,111 and 222,222 were similar (p>0.05) and higher (p<0.05) than that obtained from 55,555 in 2009. In 2010, different population produced significantly different biomass from each other, with biomass from 222,222 plants/ha being 52% greater than that from 111,111 plants/ha which was also 84% greater than from 55,555 plants/ha. Grain yield of maize from all incorporated green manure treatments were similar (p>0.05) and significantly higher (p<0.05) than from all mulched applied manure and control treatments in 2009. In 2010 maize grain yield was not significantly different across all treatments and control plots (p>0.05); highest grain yield (p>0.05) were obtained from treatments with both incorporated and mulched cowpea at 222,222 plants/ha. Grain yield of maize from all green manure plots were also higher (p>0.05) than the control plots. It was concluded that 111,111 plants/ha of Oloyin was the optimum for biomass production at 6 weeks after planting, for green manuring. Incorporating preceding cowpea green manure increased grain yield of succeeding maize. Growing cowpea at higher population density cannot make up for the losses of nutrient that would occur if the green manure is not incorporated.Â

    Development of Electrochemical Nanosensor for the Detection of Malaria Parasite in Clinical Samples

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    In this study, electrochemical nanosensors were developed from the synthesized metal oxide (MO) nanoparticles by supporting it on a gold electrode (Au). The activity of the developed nanosensor toward the detection of malaria biomarker (β-hematin) was determined and the optimum conditions at which the maximum detection and quantification occurred were established. β-Hematin current response at the sensors was higher when compared with the bare Au electrode and followed the order Au-CuO (C) > Au-CuO (M) > Au-Fe2O3 (M) > Au-Fe2O3 (C) > Au-Al2O3 (M) > Au-Al2O3 (C) > bare Au. The developed sensors were stable with a relatively low current drop (10.61–17.35 %) in the analyte. Au-CuO sensor had the best performance toward the biomarker and quantitatively detected P. berghei in infected mice's serum samples at 3.60–4.8 mM and P. falciparum in human blood serum samples at 0.65–1.35 mM concentration

    Characterizing Nigeria’s cassava seed system and the use of planting material in three farming communities

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    To archive a larger impact of seed interventions, we need to understand root, tuber and banana seed systems better. In the context of the intervention “Building an Economically Sustainable, Integrated Seed System for Cassava in Nigeria” (BASICS), there was a need to better understand the seed-sourcing behavior of cassava farmers and identify entry points for decentralized stem multipliers (DSMs). To this end a multi-stakeholder workshop provided insights into the wider landscape of Nigeria’s cassava seed system. In an explorative study we collected qualitative data via focus group discussions and complemented them with quantitative data from a survey of 90 cassava farmers in three study sites with different agro-ecological conditions. Our findings show that the cassava seed system is largely informal with vibrant stem trade within and between communities. Farmers in all study sites maintain a mix of varieties with multiple traits that is adapted to agro-ecological conditions and farmers’ preferences for use of roots. They value short maturity for early harvest, long storage of roots in the soil, bitterness as a protection against rodents, and high starch content for preparation of fufu. Although farmers in Nigeria’s South South region used only local landraces, farmers in other study sites dynamically combine those with new germplasm from the formal system. Because of a longer dry season, not all farmers are able to cover their need of planting material from their own fields alone. Despite using technologies for storage of cassava stems, there is still a demand for stems from relatives, friends, and neighbors; local traders and seed markets; and agricultural development programs. Differentiation of farmer categories by the size of their cassava fields showed no explainable pattern of different seed-sourcing behavior. Across the study population, the shortage of planting material and farmers’ interest in trying out new varieties were identified as entry points for the DSMs of the BASICS project. Further research on seed-sourcing dynamics, however, is needed to create a clear profile of stem buyers. We emphasize the importance of understanding the dynamics and the involvement of various actors in informal seed exchange to harmonize the work of DSMs in a seed system

    Family Planning Decisions, Perceptions and Gender Dynamics among Couples in Mwanza, Tanzania: A Qualitative Study.

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    Contraceptive use is low in developing countries which are still largely driven by male dominated culture and patriarchal values. This study explored family planning (FP) decisions, perceptions and gender dynamics among couples in Mwanza region of Tanzania. Twelve focus group discussions and six in-depth interviews were used to collect information from married or cohabiting males and females aged 18-49. The participants were purposively selected. Qualitative methods were used to explore family planning decisions, perceptions and gender dynamics among couples. A guide with questions related to family planning perceptions, decisions and gender dynamics was used. The discussions and interviews were tape-recorded, transcribed verbatim and analyzed manually and subjected to content analysis. Four themes emerged during the study. First, "risks and costs" which refer to the side effects of FP methods and the treatment of side -effects as well as the costs inherit in being labeled as an unfaithful spouse. Second, "male involvement" as men showed little interest in participating in family planning issues. However, the same men were mentioned as key decision-makers even on the number of children a couple should have and the child spacing of these children. Third, "gender relations and communication" as participants indicated that few women participated in decision-making on family planning and the number of children to have. Fourth, "urban-rural differences", life in rural favoring having more children than urban areas therefore, the value of children depended on the place of residence. Family Planning programs should adapt the promotion of communication as well as joint decision-making on FP among couples as a strategy aimed at enhancing FP use

    Cognitive function, social integration and mortality in a U.S. national cohort study of older adults

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    <p>Abstract</p> <p>Background</p> <p>Prior research suggests an interaction between social networks and Alzheimer's disease pathology and cognitive function, all predictors of survival in the elderly. We test the hypotheses that both social integration and cognitive function are independently associated with subsequent mortality and there is an interaction between social integration and cognitive function as related to mortality in a national cohort of older persons.</p> <p>Methods</p> <p>Data were analyzed from a longitudinal follow-up study of 5,908 American men and women aged 60 years and over examined in 1988–1994 followed an average 8.5 yr. Measurements at baseline included self-reported social integration, socio-demographics, health, body mass index, C-reactive protein and a short index of cognitive function (SICF).</p> <p>Results</p> <p>Death during follow-up occurred in 2,431. In bivariate analyses indicators of greater social integration were associated with higher cognitive function. Among persons with SICF score of 17, 22% died compared to 54% of those with SICF score of 0–11 (p < 0.0001). After adjusting for confounding by baseline socio-demographics and health status, the hazards ratio (HR) (95% confidence limits) for low SICF score was 1.43 (1.13–1.80, p < 0.001). After controlling for health behaviors, blood pressure and body mass, C-reactive protein and social integration, the HR was 1.36 (1.06–1.76, p = 0.02). Further low compared to high social integration was also independently associated with increased risk of mortality: HR 1.24 (1.02–1.52, p = 0.02).</p> <p>Conclusion</p> <p>In a cohort of older Americans, analyses demonstrated a higher risk of death independent of confounders among those with low cognitive function and low social integration with no significant interaction between them.</p

    C-Reactive Protein (CRP) Gene Polymorphisms, CRP Levels, and Risk of Incident Coronary Heart Disease in Two Nested Case-Control Studies

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    Background: C-reactive protein (CRP), an acute phase reactant and marker of inflammation, has been shown to predict risk of incident cardiovascular events. However, few studies have comprehensively examined six common single-nucleotide polymorphisms (SNPs) in the CRP gene, haplotypes, and plasma CRP levels with risk of coronary heart disease (CHD). Methods and Findings: We conducted parallel nested case-control studies within two ongoing, prospective cohort studies of U.S. women (Nurses' Health Study) and men (Health Professionals Follow-up Study). Blood samples were available in a subset of 32,826 women and 18,225 men for biomarker and DNA analyses. During 8 and 6 years of follow-up, 249 women and 266 men developed incident nonfatal myocardial infarction or fatal CHD, and controls (498 women, 531 men) were matched 2:1 on age, smoking, and date of blood draw from participants free of cardiovascular disease at the time the case was diagnosed. Among both women and men, minor alleles were significantly associated with higher CRP levels for SNPs 1919A greater than T and 4741G greater than C, but associated with lower CRP levels for SNPs 2667G greater than C and 3872C greater than T. SNP 2667G greater than C was individually associated with increased risk of CHD in both women [OR 1.57 (95% CI 1.01–2.44); p = 0.047] and men [1.93 (95% CI 1.30–2.88); p = 0.001]. Two of the five common haplotypes were associated with lower CRP levels, and Haplotype 4 which included minor alleles for 2667 and 3872 was associated with significantly lower CRP levels and an elevated risk of CHD. The remaining SNPs or haplotypes were not associated with CHD in both populations. Conclusions: Common variation in the CRP gene was significantly associated with plasma CRP levels; however, the association between common SNPs and CRP levels did not correspond to a predicted change in CHD risk. The underlying inflammatory processes which predict coronary events cannot be captured solely by variation in the CRP gene

    Geographic and Racial Variation in Premature Mortality in the U.S.: Analyzing the Disparities

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    Life expectancy at birth, estimated from United States period life tables, has been shown to vary systematically and widely by region and race. We use the same tables to estimate the probability of survival from birth to age 70 (S70), a measure of mortality more sensitive to disparities and more reliably calculated for small populations, to describe the variation and identify its sources in greater detail to assess the patterns of this variation. Examination of the unadjusted probability of S70 for each US county with a sufficient population of whites and blacks reveals large geographic differences for each race-sex group. For example, white males born in the ten percent healthiest counties have a 77 percent probability of survival to age 70, but only a 61 percent chance if born in the ten percent least healthy counties. Similar geographical disparities face white women and blacks of each sex. Moreover, within each county, large differences in S70 prevail between blacks and whites, on average 17 percentage points for men and 12 percentage points for women. In linear regressions for each race-sex group, nearly all of the geographic variation is accounted for by a common set of 22 socio-economic and environmental variables, selected for previously suspected impact on mortality; R2 ranges from 0.86 for white males to 0.72 for black females. Analysis of black-white survival chances within each county reveals that the same variables account for most of the race gap in S70 as well. When actual white male values for each explanatory variable are substituted for black in the black male prediction equation to assess the role explanatory variables play in the black-white survival difference, residual black-white differences at the county level shrink markedly to a mean of −2.4% (+/−2.4); for women the mean difference is −3.7% (+/−2.3)

    Association of Long Runs of Homozygosity With Alzheimer Disease Among African American Individuals

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    IMPORTANCE: Mutations in known causal Alzheimer disease (AD) genes account for only 1% to 3% of patients and almost all are dominantly inherited. Recessive inheritance of complex phenotypes can be linked to long (>1-megabase [Mb]) runs of homozygosity (ROHs) detectable by single-nucleotide polymorphism (SNP) arrays. OBJECTIVE: To evaluate the association between ROHs and AD in an African American population known to have a risk for AD up to 3 times higher than white individuals. DESIGN, SETTING, AND PARTICIPANTS: Case-control study of a large African American data set previously genotyped on different genome-wide SNP arrays conducted from December 2013 to January 2015. Global and locus-based ROH measurements were analyzed using raw or imputed genotype data. We studied the raw genotypes from 2 case-control subsets grouped based on SNP array: Alzheimer's Disease Genetics Consortium data set (871 cases and 1620 control individuals) and Chicago Health and Aging Project-Indianapolis Ibadan Dementia Study data set (279 cases and 1367 control individuals). We then examined the entire data set using imputed genotypes from 1917 cases and 3858 control individuals. MAIN OUTCOMES AND MEASURES: The ROHs larger than 1 Mb, 2 Mb, or 3 Mb were investigated separately for global burden evaluation, consensus regions, and gene-based analyses. RESULTS: The African American cohort had a low degree of inbreeding (F ~ 0.006). In the Alzheimer's Disease Genetics Consortium data set, we detected a significantly higher proportion of cases with ROHs greater than 2 Mb (P = .004) or greater than 3 Mb (P = .02), as well as a significant 114-kilobase consensus region on chr4q31.3 (empirical P value 2 = .04; ROHs >2 Mb). In the Chicago Health and Aging Project-Indianapolis Ibadan Dementia Study data set, we identified a significant 202-kilobase consensus region on Chr15q24.1 (empirical P value 2 = .02; ROHs >1 Mb) and a cluster of 13 significant genes on Chr3p21.31 (empirical P value 2 = .03; ROHs >3 Mb). A total of 43 of 49 nominally significant genes common for both data sets also mapped to Chr3p21.31. Analyses of imputed SNP data from the entire data set confirmed the association of AD with global ROH measurements (12.38 ROHs >1 Mb in cases vs 12.11 in controls; 2.986 Mb average size of ROHs >2 Mb in cases vs 2.889 Mb in controls; and 22% of cases with ROHs >3 Mb vs 19% of controls) and a gene-cluster on Chr3p21.31 (empirical P value 2 = .006-.04; ROHs >3 Mb). Also, we detected a significant association between AD and CLDN17 (empirical P value 2 = .01; ROHs >1 Mb), encoding a protein from the Claudin family, members of which were previously suggested as AD biomarkers. CONCLUSIONS AND RELEVANCE: To our knowledge, we discovered the first evidence of increased burden of ROHs among patients with AD from an outbred African American population, which could reflect either the cumulative effect of multiple ROHs to AD or the contribution of specific loci harboring recessive mutations and risk haplotypes in a subset of patients. Sequencing is required to uncover AD variants in these individuals
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