Ethiopian Journals Online (EJOL)
Not a member yet
4332 research outputs found
Sort by
Studies of the Cladocera (Crustacea: Branchiopoda) of Ethiopia: Current State and Further Perspectives
No full textThe cladoceran fauna of Ethiopia (East Africa) was analyzed based on original sampling data, obtained during activity of the Joint Ethio-Russian Biological Expedition. In total, we found 63 species of Cladocera in Ethiopian water bodies: 26 species of Chydoridae, 18 species of Daphniidae, 6 of Moinidae, 5 of Macrothricidae, 5 of Sididae, 2 of Ilyocryptidae and 1 of Bosminidae. The highest cladoceran diversity (39 taxa) was marked in the mountainous Lake Tana; some of them are typical only for this lake. Diverse lakes, rivers and temporary pools have lower species diversity (24 taxa in total). Water bodies of Bale Mountains are characterized by significantly low cladoceran diversity and high proportion of endemic taxa which are still waiting for detailed description. In general, Ethiopia is inhabited by typical tropical cladocerans with broad distribution ranges, cosmopolitan, circumtropical and Afrotropical-Palearctic species, as well as endemic taxa for Africa and Ethiopian high mountains regions. A cladoceran collection created as a result of our work will be a base for future taxonomic and ecological studies in Ethiopia
An Introduction to the Grasses of Ethiopia and Eritrea
No full textEthiopia together with Eritrea has a rich grass flora comprising over 600 species. Grasses typical of each of the vegetation types found in the area are discussed. Grasses from specialised edaphic conditions are considered, and also weed, pasture and lawn grasses. The paper concludes with a section on the importance of the Ethiopian highlands as a world centre of diversity for cultivated plants, with notes on indigenous cereal crop
Optimization of Media for Production of Bioactive Compounds by Streptomyces Parvullus Ss23/2 Isolated from Marine Algae in the Bay of Bengal, India
No full textStreptomyces are economically and biotechnologically valuable prokaryotes responsible for production of bioactive secondary metabolites, notably antibiotics, antitumor agents, immunosuppressive agents and enzymes. The present study deals with the optimization of media for production of bioactive compounds from Streptomyces parvullus SS23/2 isolated from marine algae (Dictyota dichotoma) at the Bay of Bengal, India. Suitable medium was selected and optimized under different chemical and physical parameters for maximum production following one-factor- at- a time approach. Optimum condition for initial pH, medium capacity, inoculum size, inoculum age, agitation and growth period were assessed and the result was found to be optimum at 7, 50 ml, 7.5% (v/v), 48 hours, 180 rpm and 6 days, respectively. Component of the best carbon source for the basal medium was sucrose at 2% and 1.5% concentration for bacteria and fungi, respectively. Malt extract at 1% concentration was the best nitrogen source for both bacteria and fungi. The composition of the best medium for Streptomyces parvullus SS23/2 was (g/l: Corn steep liquor, 10, sucrose, 20; malt extract, 10; K2HPO4, 5; NaCl, 2.5; ZnSO4, 0.04; CaCO3, 0.4; pH=7). After optimization, antimicrobial activity was improved from 36 mm to 40.7 mm inhibition zone against B. subtilis. In the research for bioactive compounds, screening, characterization and optimization of the media and cultural conditions are important for strain improvement. Therefore, optimization of products from Streptomyces in different samples may create a great potential for upscaling secondary metabolites such as antibiotics and might remain an area of research interest in the future antibiotic discover
MORPHOLOGICAL, ANATOMICAL AND PHYTOCHEMICAL STUDIES ON ZANHA GOLUNGENSIS HIERN. (FAMILY: SAPINDACEACE)
No full textZanha golungensis Hiern. is one of the commonly usedspecies of Sapindaceae in Nigeria owing to its medicinal properties; however,taxonomic data on the species are limited. In this study, morphological,anatomical and phytochemical characters of the leaf and stem of Z.golungensis were assessed with a view to add to existing literature on thespecies. Vegetative morphology, light microscopy as well as phytochemicalexaminations were performed. Taxonomically useful characters wererecorded which can be applied in the identification of Z. golungensis inpharmacognostic crude drug research without ambiguity. This is acontribution to already existing literature on the species
IDENTIFICATION OF NON-TUBERCULOUS MYCOBACTERIA FROM CLINICAL SPECIMENS REFERRED TO ADAMA TB REFERENCE LABORATORY, ETHIOPIA
No full textNon-tuberculous mycobacteria (NTM) are opportunisticpathogens that can be acquired from the environment like water and soil.They can cause pulmonary and extrapulmonary diseases in both HIV-positiveand HIV-negative individuals. There is no information in Ethiopia on theidentity and diversity of NTM in clinical specimens. The aim of this studywas to identify and characterize NTM from clinical samples stored betweenNovember 2016 to May 2017 at Adama TB reference laboratory. A total of47 NTM isolates were grouped using Runyon system and speciation wasdetermined using molecular method of GenoType Mycobacterium CM/ASassays. Of the 47 isolates, 24 (51%) were found to be slow growers while 23(49%) were rapid growers (Group IV). Of the slow growers, 4(16.7%) werephotochromogen (Group I), 7(29.2%) scotochromogen (Group II) and 13(54.2%) non-photochromogen (Group III). NTM species distribution amongidentified isolates revealed the following groups: M. intracellulare (n=6), M.abcessus/M. immunogenum (n=4), M. gordonae (n=4), M. simiae (n=3), M.fortuitum (type 1) (n=3), M. chelonae/M. immunogenum (n=1), M.scrofulaceum/M. paraaffinicum (n=1), M. avium (n=1) and M. mucogenicum(n=1). The study showed that there are different species of NTM that wereknown to cause NTM infection as well as disease. Mycobacterium aviumcomplex (Mycobacterium avium and intracellulare 29.2%) was found to bethe most common species out of the identified stains. Based on our findings,we suggest that due emphasis should be given to NTM while diagnosing TBand laboratories should be capacitated to properly identify NTM
INFLUENCE OF ABIOTIC FACTORS AND MACROPHYTE COVER ON ZOOPLANKTON DISTRIBUTION IN THE KETAR RIVER BACKWATERS
No full text: The aim of this study was to assess the relative influence ofabiotic parameters and macrophyte cover on the diversity and distribution ofzooplankton along the backwaters of the Ketar River. Six sampling sites wereselected along the river stretch and samples were collected from December2017 to November 2018. Zooplankton samples were collected from stagnantbackpools using 30 µm mesh size plankton net. A total of 36 species ofzooplankton were identified. Rotifera was represented by 28 species whileCopepoda had only 2 species. Significant difference in zooplankton taxa wereobserved between seasons and among the study sites. Downstream site 6 wasthe richest both in abundance and diversity, and the species richness wassignificantly higher in the dry season. Mesocyclops aequatorialis was adominant species in all the study sites. Electrical conductivity and totalphosphate were the main abiotic factors that positively influenced thedistribution of zooplankton in the river (Redundancy analysis). Contrary toprevious finding, significantly more diverse and abundant zooplanktoncommunities were recorded in the sites with no macrophyte cover in theKetar River. The study indicated that both spatial and temporal changes inabiotic factors were more important than macrophyte cover for zooplanktondynamics in this important influent river into Lake Ziway
THE ROLE OF GULLELE BOTANICAL GARDEN FOR BIRD CONSERVATION IN ADDIS ABABA, ETHIOPIA
No full textThis study was carried out to investigate the role of the GulleleBotanical Garden for avian conservation. Data on bird species diversity andabundance were collected during the dry (January to February 2021) and wetseasons (July to August 2021). The study area was stratified into threedominant habitat types namely nature reserve forest, modified scenic gardenand infrastructure development area. A stratified survey technique wasemployed using systematically established line transects in the three habitattypes. A total of 90 bird species belonging to 12 orders and 37 families wereidentified in the study area. Among the habitat types, the highest birddiversity was observed in the modified scenic garden habitat (H’ = 3.54),followed by the infrastructure development area (H’ = 3.29). Modified scenicgarden habitat had the highest species richness (67) followed byinfrastructure development area (58) and nature reserve forest (28).Community similarity was high between modified habitat and infrastructuredevelopment areas during the study. Gullele Botanical Garden supports twoendemic and 11 near-endemic bird species shared with Eritrea suggesting itsecological importance in avian fauna conservation. This study is the firstdetailed investigation regarding the diversity of bird species in the BotanicalGarden providing valuable information on the significance of managedhabitats with indigenous tree species to support different bird species
Reactive power management in electric power systems - A case study: EELPA 's system
No full textThe reactive power consumption by industrial plants and generation patterns in the Ethiopian Electric Light and Power Authority's (EELPA) system is critically evaluated. The flaws in the incentive mechanism for reactive power compensation are identified and recommendations made. Further, the voltage profile at the transmission level for peak and minimum loading conditions are calculated using a load flow program, the reasons for the less than satisfactory voltage stability are discussed and recommendations made
Non-stationary vibrations of mechanical systems with slowly varying natural frequencies during acceleration through resonance ( Approximate analytic solution)
No full textThe paper presents an approximate analytical solution for investigation of vibration responses in linear Single-Degree-of-Freedom-Systems (SDOF) with slowly varying natural frequency subjected to a transient excitalion force with constant amplitude. The solution employs the WBKJ-approximation method, the method of Variation of the constants and in the final analysis using error functions with complex variables. This has been used to study systems -with an ideal energy source, the excitation frequency changes linearly as function of time, the natural frequency changes slowly and linearly with time and the damping remains constant. The influence of the changing parameters on the non-stationary resonance response with special emphasis on the maximum amplitude and the speed are presented