373 research outputs found
Testing the WEAP Hydrologic Model for Awash Basin, Ethiopia “Soil Moisture Module with Watershed Demand Approach”
The research is financed by the Egyptian Government through the Nile Sector bilateral cooperation project Abstract Currently, there are several hydrological simulation models in use worldwide. Prior to adoption of a model to a specific basin, its feasibility and practicality should be tested. This study highlights on the application of Water Evaluation and Planning system (WEAP) model for hydrologic simulation of Awash river basin in Ethiopia. A monthly time step hydrologic model was developed using the soil moisture rainfall-runoff method incorporated in WEAP with an aim to check the suitability of the model for Awash river basin. For this purpose five selected flow gauge stations located at the upper, middle and lower Awash basin were used as control stations. The model is configured taking into account the effects of development and hence the water abstractions, storage, loss rate, etc. are estimated using the data provided through various kinds of research and survey in Ethiopia. Standard methods are also used to prepare the hydro-metrological and landuse input data for each sub-catchment. Based on data availability, the time period 1986-2005 was selected for the hydrologic simulation. The observed data were split for calibration (1986–1995) and validation (1996–2005) purposes. Initially, the model was set up using the default model parameters. Then, manual calibration is performed to reproduce the observed streamflow. The model-simulated values are compared with those obtained from observations using standard statistical tests on monthly and monthly average basis. From the performance test results, it is observed that the coefficient of determination (R2) and the Index of Agreement (IA) show a good fit. Furthermore, the Nash-Sutcliffe Efficiency (NSE) and the Percent Bias (PBIAS) calibration and validation results show good performance for Upper Awash stations and satisfactory results for the middle and lower Awash control stations. As a conclusion, the main modelling constraints were discussed and possible solutions were also suggested in order to improve the performance of water resources simulation models for the Awash basin. Keywords: Awash Basin, Hydrologic Simulation, Calibration, Validation, Model Performance, WEAP DOI: 10.7176/CER/12-3-07 Publication date:March 31st 202
Invitro Antibacterial Screening of Extracts from Selected Ethiopian Medicinal Plants
Indigenous knowledge, literature reports and ethnobotanical records suggest that plants are the basis for medicines. They constitute natural source of antimicrobial drugs that will provide novel or lead compounds for the fight against disease. In this study, the antimicrobial activity of three selected Ethiopian medicinal plants was studied with the objective of screening their antibacterial activity. The fruits of Measalanceolata, aerial part of Cissus quadrangularis and leaf of Dodonae angustifolia were collected, air dried under shed, powdered and soaked in 80% methanol and extracted. In vitro antibacterial activity of the extracts was tested at different concentrations by using agar disc diffusion method and measuring the zone of inhibition. The plant extracts showed broad spectrum activity against gram positive (S. aureus) as well as gram negative (E. coli) bacteria, except Cissus quadrangularis which did not show any activity against E. coli. Furthermore, the plant extracts had also concentration dependant zone of inhibition against the tested bacteria. In fact, the highest activity was obtained for Dodonae angustifolia at 1000mg/ml against S. aureus. The activities are attributed to the presence of some secondary metabolites present in the tested plants which have been associated with antibacterial activities. This finding suggests that these medicinal plants can be potential source to isolate antibacterial drugs.Keywords: Antibacterial activity, Disc diffusion, E. coli, Plant extract and S. aureus
Differences in the nutritional quality of improved finger millet genotypes in Ethiopia
Improved crop genotypes are constantly introduced. However, information on their nutritional quality is generally limited. The present study reports the proximate composition and the concentration and relative bioavailability of minerals of improved finger millets of different genotypes. Grains of finger millet genotypes (n = 15) grown in research station during 2019 and 2020 in Ethiopia, and replicated three times in a randomized complete block design, were analysed for proximate composition, mineral concentration (iron, zinc, calcium, selenium), and antinutritional factors (phytate, tannin and oxalate). Moreover, the antinutritional factors to mineral molar ratio method was used to estimate mineral bioavailability. The result shows a significant genotypic variation in protein, fat and fibre level, ranging from 10% to 14.6%, 1.0 to 3.8%, and 1.4 to 4.6%, respectively. Similarly, different finger millets genotypes had significantly different mineral concentrations ranging from 3762 ± 332 to 5893 ± 353 mg kg−1 for Ca, 19.9 ± 1.6 to 26.2 ± 2.7 mg kg−1 for Zn, 36.3 ± 4.6 to 52.9 ± 9.1 mg kg−1 for Fe and 36.6 ± 11 to 60.9 ± 22 µg kg−1 for Se. Phytate (308–360 µg g−1), tannin (0.15–0.51 mg g−1) and oxalate (1.26–4.41 mg g−1) concentrations were also influenced by genotype. Antinutritional factors to minerals molar ratio were also significantly different by genotypes but were below the threshold for low mineral bioavailability. Genotype significantly influenced mineral and antinutritional concentrations of finger millet grains. In addition, all finger millet genotypes possess good mineral bioavailability. Especially, the high Ca concentration in finger millet, compared to in other cereals, could play a vital role to combating Ca deficiency. The result suggests the different finger millet genotypes possess good nutrient content and may contribute to the nutrition security of the local people
Appraisal of the Sesame production opportunities and constraints, and farmer-preferred varieties and traits, in eastern and southwestern Ethiopia
Open access article; Published online: 11 Oct 2021Sesame (Sesamum indicum L.) is an important oilseed crop with well-developed value chains. It is Ethiopia’s most valuable export commodity after coffee (Coffea arabica L.), contributing to socioeconomic development. The productivity of the crop is low and stagnant in Ethiopia and other major sesame growing regions in sub-Saharan Africa (<0.6 t/ha) due to a multitude of production constraints. The objective of this study was to document sesame production opportunities and constraints, as well as farmer- and market-preferred varieties and traits, in eastern and southwestern Ethiopia as a guide for large-scale production and breeding. A participatory rural appraisal (PRA) study was conducted in two selected sesame growing regions and four districts in Ethiopia. Data were collected from 160 and 46 sesame farmers through semistructured questionnaires and focus group discussions. Sesame is grown by all respondent farmers in the study areas for food and as a source of cash. Most respondent farmers (56%) reported cultivating sesame using seeds of unknown varieties often sourced from the informal seed sector. About 83% of the respondents reported lack of access to improved seeds as the most important production constraint, followed by low yield gains from cultivating the existing varieties (reported by 73.8% of respondents), diseases (69.4%), and low market price (68.8%). Other production constraints included insect pests (59.4%), lack of market information (55%), and high cost of seed (50%). The above constraints were attributed to the absence of a dedicated breeding programme, lack of a formal seed sector, poor extension services, and underdeveloped pre- and postharvest infrastructures. The most important market-preferred traits of sesame included true-to-type seed (reported by 36.3% of respondents), white seed colour (28.8%), and high seed oil content (23.8%). The vital farmer-preferred attributes included reasonable market price (reported by 11.3% of respondents), resistance to crop diseases (10.9%), drought tolerance (10.3%), resistance to crop insect pests (9.2%), higher seed yield (8.9%), higher thousand-seed weight (7.2%), higher oil content (6.3%), white seed colour (6.1%), early maturity (6.1%), and good oil qualities such as aroma and taste (5.7%). Therefore, there is a need for a dedicated sesame genetic improvement programme by integrating the above key production constraints and market- and farmer-preferred traits to develop and deploy new generation varieties to enhance the production, productivity, and adoption of sesame cultivars in Ethiopia
Planning for Environmental Water Allocations: Hydrology - Based Assessment in the Awash River Basin, Ethiopia
The research is financed by the Egyptian Government through the Nile Sector bilateral cooperation project Abstract With expanding water demand due to rapid socio-economic growth and shrinking supplies due to pollution and climate change impact, there is an increasing strain on the water resources of the Awash river basin. Furthermore, flow alterations due to the existing and the ongoing water resources infrastructure projects may adversely impact the natural life cycle of aquatic ecosystems in the river basin. In order to manage these consequences, compensation releases or allocation of environmental flows may be mandatory and calls for the establishment of environmental flows framework in Ethiopia. In this study, the environmental flows at selected five existing and proposed dam sites in the Awash river basin were investigated using six worldwide used hydrology-based methods, viz.: Desktop Reserve Model (DRM), Global Environmental Flow Calculator (GEFC), Tennant, Tessman, 7Q10 and Q95. The environmental flow volumes from the six methods were compared on mean annual, monthly average and monthly basis and it is found that the predictions from the DRM and GEFC are more reliable than the others. Comparative results indicate that minimum annual average flow rates of 4.4 m3/s (15 % of Mean Annual Flow (MAF)), 10.5 m3/s (19 % of MAF), 16.4 m3/s (22 % of MAF), 2.5 m3/s (17 % of MAF) and 24.2 m3/s (26 % of MAF) are required at the immediate downstream reaches of Melka kuntre, Koka, Awash Compensation, Kesem and Tendaho dams respectively. Accordingly, the annual average environmental flow throughout the basin varies from 15-26 % of the natural MAF. Although preliminary, being the first attempt in the Awash river basin, this study is expected to stimulate dialogue among experts and decision makers in Ethiopia. Keywords: EFR, EFA, Tennant, Tessman, Q95, 7Q10, DRM, GEFC Software, Awash DOI: 10.7176/JEES/9-11-08 Publication date: November 30th 201
The effect of physical water quality and water level changes on the occurrence and density of <i>Anopheles</i> mosquito larvae around the shoreline of the Koka reservoir, central Ethiopia
Entomological studies to determine the effect of the physical characteristics of mosquito larval breeding water bodies and reservoir water level changes on the occurrence of Anopheles mosquito larvae were conducted in two villages at Koka reservoir in central Ethiopia between August and December 2007. Of the two study villages, Ejersa is located close to the reservoir, and Kuma is 5 km away from it. Data on the type, number and physical characteristics of Anopheles larval breeding habitat, species composition and densities of anopheles mosquitoes in and around the study villages were investigated and recorded. Meteorological and reservoir water level data were compared with availability of Anopheles larval breeding sites and densities. Entomological data, derived from weekly larval collections, showed that Anopheles pharoensis Theobald, Anopheles gambiae s.l. Giles, Anopheles coustani Laveran and Anopheles squamosus Theobald were breeding in the study area. The mean larval density of An. gambiae s.l. in this study was higher in slightly turbid and shallow aquatic habitat than in turbid and relatively deep aquatic habitat. The density of An. pharoensis in habitat with floating vegetation and with relatively shady conditions was significantly higher than that of less shaded aquatic habitat and greater emergent vegetation. There was also a positive correlation between the occurrence of Anopheles larvae with the water and daily minimum atmospheric temperature. Similarly at Ejersa, over the sampling period, there was a positive correlation between falling reservoir water levels and the number of positive breeding habitats. These results confirm that physical characteristics of the water bodies play an important role in the species composition, total Anopheles larval count, and the density of Anopheles mosquitoes. Suitable breeding habitat in the vicinity of the reservoir village was strongly associated with the reservoir. This is particularly important for An. pharoensis and An. gambiae s.l. which are important vectors of malaria in the area
Bayesian estimation of one-parameter qubit gates
We address estimation of one-parameter unitary gates for qubit systems and
seek for optimal probes and measurements. Single- and two-qubit probes are
analyzed in details focusing on precision and stability of the estimation
procedure. Bayesian inference is employed and compared with the ultimate
quantum limits to precision, taking into account the biased nature of Bayes
estimator in the non asymptotic regime. Besides, through the evaluation of the
asymptotic a posteriori distribution for the gate parameter and the comparison
with the results of Monte Carlo simulated experiments, we show that asymptotic
optimality of Bayes estimator is actually achieved after a limited number of
runs. The robustness of the estimation procedure against fluctuations of the
measurement settings is investigated and the use of entanglement to improve the
overall stability of the estimation scheme is also analyzed in some details.Comment: 10 pages, 5 figure
A de Haas-van Alphen study of the filled skutterudite compounds PrOsAs and LaOsAs
Comprehensive magnetic-field-orientation dependent studies of the
susceptibility and de Haas-van Alphen effect have been carried out on single
crystals of the filled skutterudites PrOsAs and LaOsAs
using magnetic fields of up to 40~T. Several peaks are observed in the
low-field susceptibility of PrOsAs, corresponding to cascades of
metamagnetic transitions separating the low-field antiferromagnetic and
high-field paramagnetic metal (PMM) phases. The de Haas-van Alphen experiments
show that the Fermi-surface topologies of PrOsAs in its PMM phase
and LaOsAs are very similar. In addition, they are in reasonable
agreement with the predictions of bandstructure calculations for
LaOsAs on the PrOsAs lattice. Both observations suggest
that the Pr 4 electrons contribute little to the number of itinerant
quasiparticles in the PMM phase. However, whilst the properties of
LaOsAs suggest a conventional nonmagnetic Fermi liquid, the effects
of direct exchange and electron correlations are detected in the PMM phase of
PrOsAs. For example, the quasiparticle effective masses in
PrOsAs are found to decrease with increasing field, probably
reflecting the gradual suppression of magnetic fluctuations associated with
proximity to the low-temperature, low-field antiferromagnetic state
Localized f electrons in CexLa1-xRhIn5: dHvA Measurements
Measurements of the de Haas-van Alphen effect in CexLa1-xRhIn5 reveal that
the Ce 4f electrons remain localized for all x, with the mass enhancement and
progressive loss of one spin from the de Haas-van Alphen signal resulting from
spin fluctuation effects. This behavior may be typical of antiferromagnetic
heavy fermion compounds, inspite of the fact that the 4f electron localization
in CeRhIn5 is driven, in part, by a spin-density wave instability.Comment: 4 pages, 4 figures, submitted to PR
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