Ethiopian Journals Online (EJOL)
Not a member yet
4332 research outputs found
Sort by
LAKE AFDERA: A THREATENED SALINE LAKE IN ETHIOPIA
Get PDFLake Afdera is a saline lake located in the Afar region, NorthernEthiopia. Because of its inaccessibility it is one of the least studied lakes of the country. It supports life including three species of fish of which two are endemic. Recently, reports are coming out that this lake is used for salt extraction. TIns paper gives some insight on the most probable wngers on the ecology of the lake if such activity is allowed to take place before environmental impact assessment was conducted
ATIACHMENT STUDY OF AGROBACTERlUM TUMEFACIENS TO TEF [ERAGROSTIS TEF (ZUCC.) TROTIER], YAM SPP., AND TOBACCO (NICOTIANA TABACCUM L.) EXPLANT
No full textAgrobacterium tumefociens attachment as a factor intransformation was investigated in tef (Eragrostis tej) zygotic embryos,seeds, seedlings, leaf bases and embryogenic callus; leaf discs of yamspecies (Dioscorea bulbifera, Diosrorea azynensis and Dioscorea alata); and leaf discs of tobacco (Nicotina tabaccum). Cocultivation was made with A1030(pCOPA10), AI030(pEB122), A1030(pTBIOS), AI030(pIB422),AI030(virA:TnS) and A281(PTi80542). Attachment and fibrils wereobserved associated in all strains, species, plants and explant used.Even though attachment is observed in intact and wounded plants,preferential attachment was observed around the wound area ofexplants. ~ni£ormity with bacteria binding was obtained withacetOsyringone treatment. The strains used equally bound to tef andyam in the same way as they did to tobacco which was a positivecontrol. Thus, tef and yam, like that of tobacco fit all the criteria forAgrobacterium attachment
Effect of elevated fry rearing temperature on survival rate, growth performance, and sex ratio of three Oreochromis niloticus populations of Ethiopian Rift Valley Lakes
No full textSex-reversal in Oreochromis niloticus is used to produce mono-sex males which are desired in aquaculture for better growth performances and population control. The present study was aimed at studying the effect of elevated fry rearing temperature on survival, sex ratios, and growth performances of O. niloticus populations of Lakes Chamo, Koka, and Ziway. Fries from five separate brood pairs of each population were either treated (T) in elevated fry rearing temperature of 36 ± 1°C or kept at room temperature of 24 ± 1°C as control (C) groups for 10 days (phase-I) and then grown in outdoor ponds for six months (phase-II). Survival rates in T groups (74.0 to 91.7%) were lower than that of C groups (83.3 to 97.0%) in all the three populations in phase-I but not in phase-II. Chamo population was better in survival rate (88.4% and 95.4% in Phase-I, and 95.4% and 95.3% in phase-II) than Koka population (85.8% and 91.3% in Phase-I, and 93.9% and 93.5% in phase-II) and Ziway population (80.2% and 88.6% in Phase-I and 90.2% and 91.9% in phase-II) both in T and C groups respectively. The Chamo population also attained significantly (p<0.05) higher mean final weight of 31.58 ± 6.78 g and 24.26 ± 6.67 g in T and C groups respectively, followed by that of Koka population with 21.70 ± 5.10 g and 18.83 ± 4.16 g while Ziway population with mean final weight of 17.49 ± 4.60 g and 16.81 ± 4.15 g was the least both in T and C groups. The overall sex ratios in T groups were skewed towards male but balanced in all C groups of each population. Better growth was achieved only in T groups with higher male ratio than their corresponding C groups. The number of sensitive brooding pairs and the overall male ratio in T groups were higher in the Koka population (40%, 61.68%) than in Ziway (20%, 56.78%) and Chamo (20%, 56.39%) populations respectively. However, the sensitivity of sex reversal to elevated fry rearing temperature was wide between individuals within each population than across the three populations. Hence, sensitive individuals can be selected from the populations and their degree of sensitivity can be improved through continuous selection of progenies from temperature-sensitive parents
Supplementary value of vetch (Vicia dasycarpa) hay as a replacement to concentrate mix in the diet of lactating crossbred cows
Get PDFAn experiment was conducted with the objective of replacing vetch for concentrate mix on feed intake and digestibility as well as milk production and composition in lactating F1 crossbred (Boran x Friesian) cows fed with a basal diet of urea-molasses-treated wheat straw. Eight crossbred cows of similar milk yield (8–10 kg d-1), body weight (BW) and stage of lactation (early lactation), but differing in parities were arranged in 4 x 4 double Latin square design. The treatments included offering urea-molasses treated wheat straw (UMTWS) ad libitum and supplementation with concentrate mix (T1), and replacement of the concentrate mix with vetch (Vicia dasycarpa) hay at a level of 25% (T2), 50% (T3) and 75% (T4). The concentrate mix consisted of 74% wheat bran, 25% noug seed (Guizotia abyssinica) cake and 1% common salt. In sacco degradability study showed that the concentrate mix and vetch were similar in rumen degradability parameters, except that rate of degradation was relatively faster for vetch hay. Total dry matter (DM) intake was significantly higher (P<0.05) for cows in T3 compared to cows in the other treatments. Nutrient intakes and apparent digestibility were non-significant (P>0.05) among treatments, except for cows in T3 that had higher (P<0.05) acid detergent fibre (ADF) intakes than cows on T1 and T2. Crude protein (CP) and metabolisable energy (ME) intakes were sufficient to meet daily requirements for the observed mean daily milk yield of 6.5 kg. Cows in T1 produced higher (P<0.05) milk yield compared to cows in T4. Milk compositions were similar (P>0.05) for cows in the different treatments. It is concluded that vetch hay could substitute up to 50% of the concentrate mix without compromising feed intake and digestibility of nutrients as well as milk yield and compositions of lactating F1 Boran x Friesian cows. 
EQUATORIAL ELECTROJET STRENGTH IN THE AFRICAN SECTOR DURING HIGH AND LOW SOLAR ACTIVITY YEARS
Get PDFINTRUSIVE EQUIVALENTS OF FLOOD VOLCANICS: EVIDENCE FROM PETROLOGY OF XENOLITHS IN QUATERNARY TANA BASANITES
Get PDFThe Injibara Quaternary basanites enclose a variety of xenoliths spanning in composition from peridotite through pyroxenite and gabbro to granite. This study focuses on the pyroxenite, gabbro and granite xenoliths. The pyroxenite xenoliths (enstatite + diopside + olivine ± spinel ± plagioclase ± ilmenite ± paragasite) are diverse, including olivine-orthopyroxenite, olivine-clinopyroxenite and websterite. They represent a suite of crystal cumulates from basalts with tholeiitic affinity evolving by polybaric crystal fractionation processes, or alternatively they may be related to chemical diversification of parental magma. The gabbro xenoliths, containing widely varying modal proportions of plagioclase, augite, enstatite, olivine and ilmenite, appear to be fragments of cumulate plutonic rocks, fractionated from tholeiitic basalts at high-level. They often show reaction textures, with a vermicular intergrowth of smaller augite, plagioclase and a chemically complex opaque phase composition embedded in glass from orthopyroxene. The granitic xenoliths contain quartz and two distinct feldspars–a sodic plagioclase and a potassic alkali feldspar– coprecipitated from the melt; accompanying mafic minerals are hydrous biotite and muscovite. This suggests that such granite magmas crystallized under water-saturated condition (PH2O = 5 kbar)
HYDROLOGICAL SYSTEM ANALYSIS AND GROUNDWATER RECHARGE ESTIMATION USING SEMI-DISTRIBUTED MODELS AND RIVER DISCHARGE IN THE MEKI RIVER BASIN
Get PDFGrounqwater recharge estimated from a soil water balance model- and from riverdischarge records were compared in the Meki River basin located in a clo~ central Main Ethiopianrift. The first method is based on soil-water balance model (WATBAL) whIch uses long~term averagemonthly hydrometeol'Ological data to quantify lumped soil water balance in three regions (rift,escarpment and highland). The second method involves estimation of recharge using discharge recordswith a computer code called BFI which uses a digital recursive filter to separate base flow from totaldaily discharge. The base flow was considered to be lumped catchment groundwater recharge withsome adjustments for upstream channel losses (14.4 mm annually) estimated from field systematic riverdischarge measurements. The results from BFI and WATBAL show general agreement on annual basis.However, the base flow seems to indicate realistic temporal variations, especially in dry seasons. Theannual weighed basin reclw'ge excluding channel loss from BFI model and WATBAL is SO.1 mm and 79.2mm respectively. The BFI model seems to provide realistic estimates of recharge for input into regionaltransient hydrological models and it also appears to be a viable method of defining the base flow fromthe river discharges against the classical manual base flow separation using regression curves. Bothlong-term and field discharge records clearly revealed that the total. flow and recharge showssubstantial temporal and spatial variations. The model results and discharge records demonstrate thatthe Meki River basin has relatively lower storilge capacity and fast response to rainfal