380 research outputs found
Methods for the evaluation of forage legumes, grasses and fodder trees for use as livestock feed
Forage plant evaluation is carried out by many institutions throughout sub-Saharan Africa. However, the approach adopted at various locations varies. This manual outlines standard evaluation methodology, which will enable researchers throughout the region to obtain meaningful results from their forage plant evaluation. This document is based on experience from the forage evaluation programme at ILCA, Kaduna. The first section deals with methodology for initial evaluation, including suitable methodology for small-plot evaluation trials and larger multi-locational trials. The second section covers methodology suitable for further evaluation of accessions identified in the initial evaluation
Reliability of non-invasive tissue sampling methods for DNA extraction in rabbits (Oryctolagus cuniculus)
[EN] Deoxyribonucleic acid (DNA) can be extracted from different tissue sources. The most common is blood, but in some situations it can be easier to take a biopsy. In some cases when it is difficult to capture animals, especially in wild populations, faeces and hairs can be considered as a source of DNA. This paper presents a pilot study conducted to compare the applicability of invasive and non-invasive sampling methods for extracting DNA for use in genetic studies of rabbits (Oryctolagus cuniculus). The study included 24 rabbits from the INRA 1001 strain. Blood, hair, ear biopsies and faeces were collected and used as DNA sources. Our aim was to verify the quantity of DNA obtained from different tissues using two or three types of extraction. DNA was obtained for all tissue types and all extraction methods. DNA extraction was shown to be optimal with the LGC (Laboratory of Cellular Genetics) blood extraction method. With regard to non-invasive methods, DNA extraction for hair using the LGC protocol and QIAamp¿ DNA mini kit gave very low quantities of DNA that could not be used for PCR reactions. The Chelex extraction protocol gave good results for PCR but could not be quantified. DNA extracted from faeces is a viable source of DNA for determining individual genotypes. The use of such non-invasive samples as a source of genetic material is a recent and very promising technique, especially for the study of endangered species, but these techniques are still too unreliable and costly to altogether replace invasive techniques when the latter are possible.Ben Larbi, M.; Tircazes, A.; Feve, K.; Tudela, F.; Bolet, G. (2012). Reliability of non-invasive tissue sampling methods for DNA extraction in rabbits (Oryctolagus cuniculus). World Rabbit Science. 20(2):117-124. doi:10.4995/wrs.2012.1077SWORD11712420
Role of persistent CMV infection in configuring T cell immunity in the elderly
Ageing is associated with declines in many physiological parameters, including multiple immune system functions. The rate of acceleration of the frequency of death due to cardiovascular disease or cancer seems to increase with age from middle age up to around 80 years, plateauing thereafter. Mortality due to infectious disease, however, does not plateau, but continues to accelerate indefinitely. The elderly commonly possess oligoclonal expansions of T cells, especially of CD8 cells, which, surprisingly, are often associated with cytomegalovirus (CMV) seropositivity. This in turn is associated with many of the same phenotypic and functional alterations to T cell immunity that have been suggested as biomarkers of immune system aging. Thus, the manner in which CMV and the host immune system interact is critical in determining the "age" of specific immunity. We may therefore consider immunosenescence in some respects as an infectious state. This implies that interventions aimed at the pathogen may improve the organ system affected. Hence, CMV-directed anti-virals or vaccination may have beneficial effects on immunity in later life
Anemia prevalence and associated factors among schoolage children in Accra and Kumasi Metropolis in Ghana
Anemia remains a serious public health concern, globally, affecting learning ability and physical development of children. Anemic children are at a higher risk of diminished economic productivity and low earning capacity in adulthood due to impaired school performance and reduced work capacity. Anemia contributes to about a quarter of Africa’s nutrition-related Disability Adjusted Life Years. The objective of this study was to determine the prevalence of anemia and its associated risk factors among school-aged children (SAC) between ages 9 and 15 years in urban Ghana. The analysis included a randomly selected subsample of 1,634 children from a larger study on nutrition of SAC enrolled between 2009 and 2012 in private and public basic schools in the Accra and Kumasi Metropolis in Ghana. Socio-demographic and household characteristics were collected with questionnaires. Weight and height were taken to the nearest 0.1kg and 0.1cm, respectively. Dietary information was collected using a food frequency questionnaire. Data were analyzed using IBM SPSS Statistic version 23. The relationship between hemoglobin levels and socio-demographic variables, and predictors of hemoglobin levels were determined using Chi-square and binary logistic regression. The mean hemoglobin concentration of the study participants was 12.9±1.3 g/dL. In Kumasi, SAC had higher mean hemoglobin concentration (13.1±1.2 g/dL) compared to those from Accra (12.6±1.3 g/dL; p=0.001). Mean hemoglobin concentration was significantly higher among males than females (13.0±1.4 g/dL vs 12.8±1.2 g/dL; p=0.002). Prevalence of anemia was 20.4%; mild anemia was most common (13.6% of total sample). Anemia cases were higher in public schools (24.6%) compared to private (18.2%). Two-thirds of anemia cases (64.0%) were from schools in Accra. Males had significantly higher prevalence of anemia (26.5%) than females (15.9%; p <0.05). In the adjusted logistic regression model, only city of residence (OR+1.65, 95% CI: 1.44–1.83), thinness (OR=2.60, 95% CI: 1.11-5.75), stunting (OR=1.85, 95% CI: 1.99-3.10) and overweight (OR=0.60, 95% CI: 0.36-0.94) were significantly associated with anemia. In this study, anemia was significantly associated with location and nutritional status
Anemia prevalence and associated factors among school age children in Accra and Kumasi metropolis in Ghana
Anemia remains a serious public health concern, globally, affecting learning ability and physical development of children. Anemic children are at a higher risk of diminished economic productivity and low earning capacity in adulthood due to impaired school performance and reduced work capacity. Anemia contributes to about a quarter of Africa’s nutrition-related Disability Adjusted Life Years. The objective of this study was to determine the prevalence of anemia and its associated risk factors among school-aged children (SAC) between ages 9 and 15 years in urban Ghana. The analysis included a randomly selected subsample of 1,634 children from a larger study on nutrition of SAC enrolled between 2009 and 2012 in private and public basic schools in the Accra and Kumasi Metropolis in Ghana. Socio-demographic and household characteristics were collected with questionnaires. Weight and height were taken to the nearest 0.1kg and 0.1cm, respectively. Dietary information was collected using a food frequency questionnaire. Data were analyzed using IBM SPSS Statistic version 23. The relationship between hemoglobin levels and socio- demographic variables, and predictors of hemoglobin levels were determined using Chi-square and binary logistic regression. The mean hemoglobin concentration of the study participants was 12.9±1.3 g/dL. In Kumasi, SAC had higher mean hemoglobin concentration (13.1±1.2 g/dL) compared to those from Accra (12.6±1.3 g/dL; p=0.001). Mean hemoglobin concentration was significantly higher among males than females (13.0±1.4 g/dL vs 12.8±1.2 g/dL; p=0.002). Prevalence of anemia was 20.4%; mild anemia was most common (13.6% of total sample). Anemia cases were higher in public schools (24.6%) compared to private (18.2%). Two-thirds of anemia cases (64.0%) were from schools in Accra. Males had significantly higher prevalence of anemia (26.5%) than females (15.9%; p <0.05). In the adjusted logistic regression model, only city of residence (OR+1.65, 95% CI: 1.44–1.83), thinness (OR=2.60, 95% CI: 1.11-5.75), stunting (OR=1.85, 95% CI: 1.99-3.10) and overweight (OR=0.60, 95% CI: 0.36-0.94) were significantly associated with anemia. In this study, anemia was significantly associated with location and nutritional status
The Politics of Service Delivery Reform
This article identifies the leaders, the supporters and the resisters of public service reform. It adopts a principal–agent framework, comparing reality with an ‘ideal’ situation in which citizens are the principals over political policy-makers as their agents, and policy-makers are the principals over public service officials as their agents. Reform in most developing countries is complicated by an additional set of external actors — international financial institutions and donors. In practice, international agencies and core government officials usually act as the ‘principals’ in the determination of reforms. The analysis identifies the interests involved in reform, indicating how the balance between them is affected by institutional and sectoral factors. Organizational reforms, particularly in the social sectors, present greater difficulties than first generation economic policy reforms
Immune profiling of Alzheimer patients
Alzheimer's disease (AD) is characterized by extracellular senile plaques in the brain, containing amyloid-β peptide (Aβ). We identify immunological differences between AD patients and age-matched controls greater than those related to age itself. The biggest differences were in the CD4+ rather than the CD8+ T cell compartment resulting in lower proportions of naïve cells, more late-differentiated cells and higher percentages of activated CD4+CD25+ T cells without a Treg phenotype in AD patients. Changes to CD4+ cells might be the result of chronic stimulation by Aβ present in the blood. These findings have implications for diagnosis and understanding the aetiology of the diseas
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Behavior of Circular Fiber-Reinforced Polymer-Steel-Confined Concrete Columns Subjected to Reversed Cyclic Loads: Experimental Studies and Finite-Element Analysis
This paper studied experimentally the behavior of circular fiber-reinforced polymer (FRP)-steel-confined concrete columns subjected to reversed cyclic loads. The influence of main structural factors on the cyclic behavior of the columns is discussed. Test results showed the outstanding seismic performance of FRP-steel-confined RC and steel-reinforced concrete (SRC) columns. The lateral confinement effectiveness of glass fiber-reinforced polymer (GFRP) tubes and GFRP-steel tubes was verified and a simplified OpenSees-based finite-element method (FEM) model was developed to simulate the experimental results of the test columns. Based on the proposed FEM model, a parametric analysis was conducted to investigate the effects of main factors on the reversed cyclic behavior of GFRP-steel-confined RC columns. Based on the test and numerical analyses, the study discussed the influence of variables such as the lateral confinement on the plastic hinge region (PHR) height and peak drift ratio of the columns under reversed cyclic loads. Results indicate that lateral confinement significantly affects the PHR height of circular confined RC columns. Based on the analyses of the data from this study and literature, a simple model was suggested to predict the peak drift ratio of confined RC columns
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Monotonic axial compressive behaviour and confinement mechanism of square CFRP-steel tube confined concrete
Steel tube confined concrete (STCC) is widely used in the vertical members of high-rise buildings such as columns. The axial load is not directly resisted by the steel tube in STCC, but is resisted via the interfacial frictional stress between steel tube and concrete core, which is different with that of concrete filled steel tube (CFT) members and would effectively suppress the outward local buckling of steel tube at early stage. Recently, fibre-reinforced polymer (FRP) confined STCC presents a potential to enhance the ductility and durability of such vertical elements. This paper presents an experimental study on monotonic axial compressive behaviour of carbon FRP (CFRP) confined STCC (CFRP-STCC) stub column and an analytical study on the confinement mechanism of and the ultimate axial bearing capacity of the elements. A three-stage confinement mechanism involving the different contributions of the steel tube and the CFRP wrap in CFRP-STCC elements was proposed based on the test results. A prediction model of the ultimate axial bearing capacity of CFRP-STCC stub columns was developed subsequently. Results show that the presence of CFRP wrap enhances effectively the load-bearing capacity and the ductility of steel tube confined plain concrete and reinforced concrete elements, and significantly prevents the local buckling of the steel tubes in the elements. The proposed prediction model of ultimate axial bearing capacity assesses test results with a great agreement
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