Critical Applied Linguistics: Concerns and Domains

Critical applied linguistics seems a new phenomenon and a point under the study. Thus much has not been written and wider debts were not made on it whether to be kept as an autonomous discipline or to be studded just under mainstream division, applied linguistics. So, the intention of the current article is to just mention some points on the issue focusing on concerns and domains in brief. So it will contribute to the amelioration of the disciplines

Inter Simple Sequence Repeat (ISSR) analysis of wild and cultivated rice species from Ethiopia

The genetic diversity of three wild rice populations of Ethiopia along with three cultivated rice populations were studied using Inter simple sequence repeats (ISSRs) as a molecular marker. A total of 93 clear and reproducible bands were generated using four dinucleotides and two tetra nucleotides primers. Both UPGMA and neighbor joining trees were constructed for each individual and population using Jaccard’s similarity coefficient. The trees and PCO clearly indicated six distinct groups which are based on populations of origin. Oryza glaberrima, Oryza sativa and NERICA-3 clustered as a major group while Oryza barthii and Oryza longistaminata were clustered as the second major group. Such clustering of O. glaberrima with O. sativa and NERICA-3 is considered to be due to genetic admixture of O. glaberrima with O. sativa. The over all gene diversity and percent polymorphisms were found to be higher in wild rice (0.14; 38.3 respectively) than in cultivars (0.11; 28.3 respectively). The Shannon’s diversity index also confirmed the existence of higher diversity in wild rice populations than cultivated species. Furthermore, partitioning of the Shannon’s diversity showed that the majority of the variations were observed among population (63%). Similarly, AMOVA demonstrate highly significant (P = 0.00) genetic differences among populations (72.9) than within populations (27.1).Key words: Genetic diversity, wild rice populations, cultivated rice, Oryza sativa, Oryza glaberrima, NERICA, ISSR

Genetic diversity and population structure of Ethiopian lentil (Lens culinaris Medikus) landraces as revealed by ISSR marker

Characterization of genetic resources maintained at genebanks has important implication for future utilization and collection activities. The objective of this study was to assess the level of geneticdiversity, genetic structure and genetic distance, and to indirectly estimate the level of gene flow among populations of Ethiopian lentil landraces using intersimple sequence repeat (ISSR) marker. Forthis purpose, seeds of seventy landrace accessions collected from seven different administrative regions of Ethiopia were obtained from Inistitute of Biodiversity Conservation and grown at SinanaAgricultural Research Center (Bale-Robe, Ethiopia) on-station field plot. DNA was extracted from a bulk leaf sample of fifteen randomly selected seed-raised plants using a triple CTAB extraction technique.ISSR data were generated using four primers. The total genetic diversity ( T H ), the intrapopulation genetic diversity ( S H ) and the interpopulation genetic diversity ( ST D ) were 0.175, 0.095 and 0.079,respectively. High intrapopulation genetic diversity was observed for Gonder, Shewa and Wello populations, while Arsi, Bale, Tigray and Gojam populations showed low intrapopulation diversity.There was high genetic differentiation (GST = 0.455) but intermediate gene flow level (Nm = 0.60) among populations. The genetic distance ( D ) between populations ranged from 0.012 – 0.228. Cluster analysisrevealed two groups of Ethiopian lentil landrace populations. The results provide important baseline for future germplasm conservation and improvement programs

The association of TB with HIV infection in Oromia Regional National State, Ethiopia in 2006/7

Background: Infection with Human Immunodeficiency Virus (HIV) is an established risk factor for tuberculosis infection. Population-based data on associations between HIV and tuberculosis (TB) can provide an epidemiological assessment of the impact of HIV infection on TB in environments where individual based data are difficult to collect.Method: We used an ecological study to assess the association between infection with HIV and tuberculosis in Oromia Region National State, Ethiopia in 2006/7.Result: The prevalence of HIV infection was significantly associated with the incidence of TB across the areas in Oromia region (r=0.69,

Applications of Virus Induced Gene Silencing (VIGS) in Plant Functional Genomics Studies

Virus induced gene silencing (VIGS) is an effective technology that exploits an antiviral defense mechanism in plants. It is a recently developed gene transcript suppression technique for characterizing the function of plant genes. VIGS is rapid, efficient and specific system for transient gene silencing. The major steps in VIGS includes; engineering viral genomes to the appropriate viral vector to incorporate fragments of host genes that are targeted to be silenced, infecting the appropriate plant hosts and silencing the target genes as part of the defense mechanism of the plant against virus infection. The VIGS vector is a recombinant virus engineered to be able to carry a piece an endogenous gene from the host. During infection with the modified vector, the host’s defense reaction will be induced against the cloned host gene; a loss of function phenotype makes it possible to identify the function of the gene. The recombinant virus is introduced into plant cells through Agrobacterium tumefaciens mediated transient expression or in vitro transcribed RNA inoculation or direct DNA inoculation. The Trans gene is amplified along with the viral RNA by RNA dependent RNA polymerase generating dsRNA molecules. dsRNA is the triggering molecule of Post transcriptional gene silencing. VIGS as a reverse genetics tool for functional genomics studies presenting several advantages. Despite its great potential, many limitations remain to be overcome. In this review, the molecular mechanism in VIGS technology, its advanced application in plant functional genomics studies and the major limitation and potential future prospects were briefly discussed

Recent Developments in Genomic Selection for Minor Gene Quantitative Disease Resistance Plant Breeding

To speed up the development of improved crop varieties, genomics assisted plant breeding is becoming an important tool. With traditional breeding and marker assisted selection, there have been several achievements in breeding for diseases resistance. Most research for disease resistance has been focused on major disease resistance genes which are highly effective although very vulnerable to breakdown with rapid changes in pathogenic races. In contrast, breeding for minor gene quantitative resistance can produce more durable plant varieties although it is very slow and challenging breeding. As the genetic architecture of the plant disease resistance shifts from single major R genes to many minor quantitative genes, the most appropriate approach for molecular plant breeding is genomic selection (GS) than marker assisted selection or conventional breeding. With the advent of new genomic tools, GS has emerged as one of the most important approaches for predicting genotype performance to improve genetically complex quantitative traits. Consequently, GS helps to accelerate the rate of genetic gain in breeding by using whole genome sequence data to predict the breeding value of offspring. GS breeding for quantitative resistance will therefore necessitate whole genome prediction models and selection methodology as implemented for classical complex traits. With the implementation of GS for yield and other economically important traits, whole genome marker profiles are available for the entire set of breeding lines, enabling genomic selection for disease resistance with no additional direct cost. Therefore, recent developments in GS including a two stream GS + de novo GWAS models (GS+) and GS for combined highest level of quantitative resistance with R genes (QR +R gene) individuals are expected to further advance disease resistance plant breeding and briefly discussed

Experimental Investigation on Mechanical and Turning Behavior of Al 7075/ x

The present research work involves the study of AA 7075-TiB2-Gr in situ composite through stir casting route. This in situ method involves formation of reinforcements within the matrix by the chemical reaction of two or more compounds which also produces some changes in the matrix material within the vicinity. Titanium Diboride (TiB2) and graphite were the reinforcement in a matrix of AA 7075 alloy. The composite was prepared with the formation of the reinforcement inside the molten matrix by adding salts of Potassium Tetrafluoroborate (KBF4) and Potassium Hexafluorotitanate (K2TiF6). The samples were taken under casted condition and the properties of the composite were tested by conducting characterization using X-ray diffraction (XRD), hardness test, flexural strength by using three-point bend test, scanning electron microscope (SEM), optical microstructure, grain size analysis, and surface roughness. It was found that good/excellent mechanical properties were obtained in AA 7075-TiB2-Gr reinforced in situ hybrid composite compared to alloy due to particulate strengthening of ceramic particles of TiB2 in the matrix. Further, Al 7075-3% TiB2-1% Gr hybrid in situ composite exhibited improved machinability over the alloy and composites due to self-lubricating property given by the Gr particles in the materials