275 research outputs found
MORPHOMETRIC STUDY OF THE REPRODUCTIVE SYSTEM OF GIANT AFRICAN LAND SNAIL Archachatina marginata ovum (Pfeiffer) (Pulmonata: Achatinidae) FOUND IN ILE-IFE, SOUTHWESTERN NIGERIA.
The morphometry of the reproductive organs of the giant African land snail, Archachatina marginata ovum from wild collection at Ile-Ife, southwest Nigeria, was assessed during March - May (early rainy season) and August – October (late rainy season) of 2010. A total 134 snails were dissected and clas-sified into one of five different reproductive states (low mating readiness; high mating readiness; egg production; gravid and post reproductive). The five states were observed in snails collected during the early rainy season, whereas the gravid state was not observed in the collections during late rainy sea-son. Albumen gland was considerably enlarged at egg production state forming about 60 % of the total weight of the reproductive system, while vas deferens was significantly longer in snails at high mating readiness state. The sizes of the reproductive organs were not substantially related to the size of the snail as the coefficient of determination (r2) of the relationship were in most cases below 0.5. The over-all results indicated that variations in the morphology of the reproductive organs of A. marginata ovum are mostly state dependent and less related to the size of the snail and thus could be used reliably to categorise the snails into reproductive states
Association of polymorphisms in the aldosterone-regulated sodium reabsorption pathway with blood pressure among Hispanics
Background: Whereas genome-wide association study (GWAS) has proven to be an important tool for discovery of variants influencing many human diseases and traits, unfortunately its performance has not been much of all-around success for some complex conditions, for example, hypertension. Because some of the existing effective pharmacotherapeutic agents act by targeting known biological pathways, pathway-based analytical approaches could lead to more success in discovery of disease-associated variants. The objective of the present study was to identify functional variants associated with blood pressure in the aldosterone-regulated sodium reabsorption pathway using the simulated and real blood pressure phenotypes provided for Genetic Analysis Workshop 19. Methods: The present analysis included 1942 samples with exome sequencing data and for whom blood pressure phenotypes were available. Because only odd-numbered autosomes were available, we restricted analysis to 127 quality-controlled single-nucleotide polymorphisms from the aldosterone-regulated sodium reabsorption pathway. We performed pathway-based association analysis using appropriate regression models for single variant, haplotype and epistasis association analyses. To account for multiple comparisons, statistical significance was empirically derived by permutation procedure and Bonferroni correction. Results: The topmost pathway-based association signals were observed in PRKCA gene for diastolic blood pressure (DBP), systolic blood pressure (SBP), and mean arterial pressure (MAP) in both real and simulated data. The associations remained significant (P \u3c0.05) after multiple testing corrections for the number of genes. Similarly, the pathway-based 2-locus epistasis analysis indicated significant interactions between INSR and PRKCG for SBP and MAP; INS and PIK3R2 for DBP; PIK3CD and ATP1B2 for hypertension in the real data set. We also observed significant within-gene interactions in INSR for SBP, DBP, and hypertension in the simulated data set. Conclusion: The findings from this study show that pathway-based analytical approach targeting known biological pathways can be useful in identification of disease-associated variants that are otherwise undetectable by GWAS. The approach takes advantage of the assumption of nonindependence of variants within and across pathway genes which leads to reduced penalty of multiple testing and thus less-stringent statistical significance threshold
Potential benefits of genetic modification (GM) technology for food security and health improvement in West Africa: Assessing the perception of farmers in Ghana and Nigeria
We assessed the perception of farmers towards potential adoption of genetic modification (GM) technology for improving health, food security and agricultural productivity using a semi-structured interview. A total sample of 54 small-scale farmers participated in 6 focus group meetings (FGMs) and 23 in-depth interviews at six locations in Ghana and Nigeria (West Africa). Our results reveal that most farmers have a very poor understanding of GM technology which they often misunderstood as traditional plant breeding biotechnology. While most respondents focused on the potential benefits of GM technology including high-yielding varieties, better nutritional value and shorter growing cycle crop traits, only a few respondents were concerned about the potential health and environmental risks of GM technology. Root and tuber crops such as cassava, yam and sweet potato were mostly discussed for health improvement and food security through GM technology. This study emphasizes the need to recognize challenges such as lack of awareness, inadequate training, low level of education and poor extension services among others in introducing new technology including GM technology to resource poor farmers in African countries like Ghana and Nigeria. We conclude that failure to address these challenges will impede the adoption of GM technology. Therefore, Ghanaian and Nigerian government(s) must put in place policy measures to address these problems.Keywords: Food security, health improvement, genetic modification (GM) technology, Ghana, Nigeria, West Africa farmersAfrican Journal of Biotechnology, Vol. 13(2), pp. 245-256, 8 January, 201
Proximate Composition and Amino Acid Profile of Raw and Cooked Black Variety of Tiger nut (Cyperus esculentus L.) Grown in Northeast Nigeria
Tiger nut (Cyperus esculentus L.) is an underutilized tuber of family Cyperaceae which produces rhizomes from the base of the tuber that is somewhat spherical. The three varieties of yellow, brown and black tiger nut are grown in Nigeria. Proximate and amino acid compositions of raw and cooked black variety of Cyperus esculentus were investigated using standard analytical techniques. The respective proximate composition values (%) for the raw and cooked samples were: Moisture (3.73 and 4.66), ash (2.57 and 3.38), crude fat (8.94 and 9.92), crude protein (12.09 and 9.25), crude fibre (7.02 and 4.52), and carbohydrate (65.66 and 69.29). The calculated fatty acids and metabolizable energy for the raw and cooked samples were 7.15 and 7.94%; 1652.53 and 1702.22 kJ/100g, respectively. The values of metabolizable energy in this study showed that both samples have energy concentrations more favourable than cereals. The amino acid profile revealed that raw and cooked samples of Cyperus esculentus contained nutritionally useful quantities of most of the essential amino acids with total essential amino acid (TEAA) (with His) were 45.69 and 48.25%, respectively. The value of predicted protein efficiency ratio (P–PER) for the raw tuber was 2.77, the value is higher than the reported P–PER values of some legumes in the literature. However, essential amino acid supplementation may be required in Ile, Leu, TSAA and Val when comparing the EAA in this report with the recommended FAO/WHO provisional pattern. The limiting EAAs in the raw and cooked Cyperus esculentus tuber were Leu and TSAA, respectively. Keywords: Proximate, amino acids, tigernu
Investigation of the Properties of “Pure Water” Sachet Modified Bitumen
The increasing volume of traffic loads on our roads is currently a challenge on flexible pavement design and construction. Factors such as durability, strength and economic needs have to be considered in the design and construction of road pavement. Many researches have been conducted to explore supplementary material that can make a durable asphalt pavement. It is not unfamiliar that the modification of bitumen with the use of polymers enhances its performance characteristics but at the same time significantly alters its rheological properties. One of the environmental issues in most regions of Nigeria is the large number of polymeric wastes made from polyethylene water sachet (PWS) popularly called “Pure Water” Nylon deposited in domestic wastes and landfills. This study was conducted to investigate the effect of PWS on the properties of conventional bitumen and suitability of discarded PWS as bitumen modifier and to reduce the environmental effects of PWS disposal. Bituminous blends containing PWS at various percentages 2.5%, 5%, 7.5%, 10%, 12.5% and 15% weight of conventional bitumen. Penetration, softening point and float tests were carried out on the samples to evaluate the penetration index, viscosity, stiffness modulus and the suitability of PWS as bitumen modifier. Sieve analysis and infrared spectroscopy of the shredded PWS sample were also carried out. Result obtained from tests was compared between control sample (0% PWS) and PWS modified samples. The test results show that PWSs influence more on the penetration of the modified sample with the increase in the viscosity of the bitumen as can be observed by the decrease in the value of penetration with the increase in concentration of PWS. The penetration index values of Samples 2.5% PWS and 7.5% PWS makes them to be classified as blown bitumen and the PI value of Sample 5% PWS makes it less susceptible to temperature changes and can be classified as oxidized bitumen. PWS is a cheap and readily available material in construction when used appropriately in bitumen and the recycling of PWS for asphalt base roads helps alleviate an environmental problem and saves energy. Keywords: Bitumen, pure water sachet (PWS), infrared spectroscopy analysis, penetration test, softening point, viscosity tes
Microanatomical effects of ethanolic extract of Cola nitida on the stomach mucosa of adult wistar rats
The study investigated the microanatomical effects of the extracts of Cola nitida on the stomach mucosa of adult male Wistar rats. Twenty adult male wistar rats were randomly divided into four equal groups of A, B, C and D (n=5). Animals in experimental groups B, C and D were given 600mg/kg body weight of crude extract of Cola nitida each by oral intubation for five, seven and nine consecutive days respectively, while group A (control) received equivalent volume of distilled water. Twenty four hrs after the last administration, the animals were sacrificed; tissues were harvested and fixed in 10% formol saline for histological analysis. The study revealed necrotized surface epithelium, degenerated gastric mucosa, and loss of glandular elements in the stomachs of experimental groups’ vis-à -vis the control group. These observations were days-dependent; as those groups which received the extract for higher number of days were seen to be adversely affected. In conclusion, Cola nitida at 600mg/kg body weight can cause gastric lesion in animals. This lesion may be pronounced if the administration continued for days. Cola nitida should, therefore, be taken with caution to avoid gastric complications.Keyword: Cola nitida, necrotized, degenerated, stomach mucosa, microanatomy, glandular element
Association of regions on chromosomes 6 and 7 with blood pressure in Nigerian families
Background: Elevated blood pressure (BP) shares a level of heritability similar to many other traits related to cardiovascular risk; however, specific susceptibility loci have been difficult to localize. We conducted a multistage study of BP as a continuous trait in a low-risk West African population in which it was anticipated that environmental exposures would be reduced in complexity and intensity. In our earlier genome-wide linkage study for BP in this population, strong linkage evidence was noted on chromosomes 6 and 7. Methods and Results: We subsequently genotyped a total of 3431 tag single-nucleotide polymorphisms (SNPs) in 3 regions (viz, 152.68 to 165.99 Mb on chromosome 6, 0.29 to 20.67 Mb, and 104.09 to 123.06 Mb on chromosome 7) in 713 individuals from 199 families. We conducted a family-based association analysis using individual SNPs and associated haplotypes. After correction for multiple comparisons, 6 intronic and 1 intergenic SNPs achieved nominal statistical significance (P\u3c0.05) for the association with BP. The associated intronic SNPs include 2 in the PARK2 gene on chromosome 6; 2 in the KCND2 gene, and 1 each in the C7orf58 and HDAC9 genes on chromosome 7. The intergenic SNP is located between the RPA3 and GLCCI1 genes on chromosome 7. The haplotypes on which these SNPs resided were more strongly associated with BP than their respective single SNPs. The frequency of the at-risk haplotypes ranged from 14% to 48%. Conclusions: These data provide preliminary evidence that regions on chromosomes 6 and 7 may influence susceptibility to elevations in BP. © 2009 American Heart Association, Inc
The Effects of Gray Markets in the International Product Distribution Systems
The problem of gray markets has become one of the main concerns to many global marketing firms. Many of the distribution goals of today’s firms in the international arena have been thwarted by the activities and issues of gray marketing. This work, therefore, analyzes the incidence of gray markets in the international distribution system. The study is guided by the following objectives: to examine if gray marketing affects product defection as well as encourage increasing customers’ complaint; to examine the effects of gray markets activities on the availability of goods in certain part of the world; and to ascertain whether the realization of distribution objectives in the international marketing environment is affected by the incidence of gray market. To achieve the objectives spelled out, the study utilizes descriptive research. The questionnaire was the main research instrument that the study used to sift data from a sample of 50 respondents who were consumers. Based on the analyzed data, the following findings were made: that gray market affects product defection and hence, it leads to increasing customer complaints of certain product in the foreign markets; that gray market leads to negative availability of good in certain parts of the world; and that, gray market affects the realization of distribution goals and objectives of some organizations in international marketing environments. Guided by the findings, the study concludes that gray markets have a very strong effect on the international distribution Systems, causing dumping of good in certain target foreign markets and leading to non-realization of place utility objective by some global firms. The study recommends that gray markets should be minimized through utilization of internet technology, lowering costs to reliable distributors and as well ensuring effective selection of middlemen. Keywords: gray market, distribution, international systems and parallel importing
The Challenges of e-Tailing in Employment Creation: Empirical Evidence from Nigeria
As more and more manufacturers and retailers turn to e-tailing to increase profits and capture new customers, the emphasis on online shopping means more opportunities for web designer jobs and developer jobs, not to mention an increase in the number of marketing jobs and content roles. This paper investigates the retail sector contribution and strategies for job creation. The research is based on a wide and broad literature review of the latest trends in the Nigeria retail industry, followed and supplemented by quantitative research of the key retailers in the country. The work, among others things identifies the drivers of change and related factors that have a bearing and influence on employment creation based on the emerging opportunities and threats (e.g. Technology). The study also evaluates the effect of e-retailing on job creation in Nigeria and as well investigates the challenges for managing e-tailing in a developing economy. To achieve the spelt objectives, the study utilizes survey design; and data was collected though a self-administered questionnaire from a number of 302 respondents who were retailers in three selected open markets in Ibadan Metropolis, Oyo State Nigeria. Statistical technique software SPSS was employed to aid the data analysis. Having analyzed the data, the study found out that e-tailing has brought about changes in the ways people buys and this affects many traditional retail outlets. It was also discovered that e-tailing is still ineffective in Nigeria economy. The work among other things, recommends that brick and mortal retailers should strengthen their operations in order to continue being in business. The work in addition to that also advised that Nigeria manufacturers and retailers should go electronic so as to face the digital rivals created by e-tailers
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