East African Journal of Sciences最新文献

{"title":"The Mathematical Basis of the Calendar Used by the Ethiopian Orthodox Twahedo Church for Fasting Periods and Religious Holidays","authors":"S. Tafesse","doi":"10.4314/EAJSCI.V2I1.40368","DOIUrl":"https://doi.org/10.4314/EAJSCI.V2I1.40368","url":null,"abstract":"The Ethiopian Orthodox Twahedo Church (EOTC) has been the most dominant religion fully supported by the government for many years. EOTC has its own calendar, which is genuinely respected by the people. Nowadays, the Ethiopian people officially celebrate five major religious holidays every year: the New Year called ‘Inqutatash’, Holy Cross, Christmas, Epiphany and Easter. Easter has no fixed date. The dates of some of the fasting periods and the religious holidays also vary from year to year. In this paper, number theory is applied to the determination of the calendar for the fasting periods and major holidays of the EOTC whose dates vary from year to year.","PeriodicalId":33393,"journal":{"name":"East African Journal of Sciences","volume":"2 1","pages":"79-85"},"PeriodicalIF":0.0,"publicationDate":"2008-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4314/EAJSCI.V2I1.40368","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70512774","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Leaf Area Estimation Models for Ginger (Zingibere officinale Rosc.)","authors":"A. Netsere, G. Hailemichael, E. Taye","doi":"10.4314/EAJSCI.V2I1.40360","DOIUrl":"https://doi.org/10.4314/EAJSCI.V2I1.40360","url":null,"abstract":"The study was carried out to develop leaf area estimation models for three cultivars (37/79, 38/79 and 180/73) and four accessions (29/86, 30/86, 47/86 and 52/86) of ginger. Significant variations were observed among the tested genotypes in leaf length (L), leaf width (W) and actual leaf area (ALA). Leaf area was highly correlated with L  W, followed by L + W, L and W. Regression equations developed for the aforementioned cultivars and accessions were Y = 13.6 + 1.204X, Y = 4.244 + 1.349X, Y = 0.516 + 1.428X, Y = -54.627 + 2.201X, Y = 1.811 + 1.421X, Y = -2.386 + 1.489X and Y = -4.614 + 1.831X respectively, where Y is estimated leaf area (ELA) and X is L  W, and have R2 ranged between 0.916 and 0.942. Simple constants (K) were also derived from L  W and have the values of 1.454, 1.458, 1.396, 1.626, 1.433, 1.586 and 1.429 for the respective genotypes. On all cultivars and accessions, the correlation coefficients (r) computed between ALA and ELA [K (L  W)] were positive and significant (p < 0.01). Hence both the regression models and K developed are employed equally for estimating the areas of intact ginger leaves.","PeriodicalId":33393,"journal":{"name":"East African Journal of Sciences","volume":"2 1","pages":"25-28"},"PeriodicalIF":0.0,"publicationDate":"2008-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4314/EAJSCI.V2I1.40360","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70512286","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of Plant Density on Morphological Characteristics, Yield and Chemical Composition of Napier Grass ( Pennisetum purpureum (L.) Schumach)","authors":"T. Zewdu","doi":"10.4314/EAJSCI.V2I1.40365","DOIUrl":"https://doi.org/10.4314/EAJSCI.V2I1.40365","url":null,"abstract":"An experiment to assess the effect of plant density on morphological characteristics, dry matter production and chemical composition of Napier grass ( Pennisetum purpureum (L.) Schumach) was conducted in 2004 and 2005 at Haramaya University, eastern Ethiopia. There were a total of nine treatments with 1.5, 1 and 0.5m spacing between rows and 0.75, 0.5 and 0.25m spacing between plants, which consisted of 8,888.9, 13,333.3, 26,667.7, 13,333.3, 20,000, 40,000, 26,667.7, 40,000, and 80,000 plants per ha, arranged in a randomized complete block design with three replications. The plot size was 3m width x 6m length and the spacings between replications and plots were 1.5m and 1m respectively. There was no significant (P > 0.05) effect in morphological characteristics of Napier grass due to plant density during the establishment year. However, the number of tillers, total leaves, internode number, internode length, basal circumference and leaf length per plant were significantly (P 0.05) effect on the chemical composition of Napier grass due to plant density. However, the crude protein (CP) content of all the treatments was above 15%, which is the optimum required for animal growth or production. The fibre fractions were also below the threshold level (600 g/kg DM) at which DM intake of cattle is affected. Based on DM yield production and CP content, the production of Napier grass using 40, 000 plants per hectare is recommended to livestock producers in eastern Ethiopia agro-ecologies of the country. Keywords : Chemical Composition; Dry Matter Yield; Morphological Characteristics; Napier Grass; Plant Density East African Journal of Sciences Vol. 2 (1) 2008: pp. 55-61","PeriodicalId":33393,"journal":{"name":"East African Journal of Sciences","volume":"2 1","pages":"55-61"},"PeriodicalIF":0.0,"publicationDate":"2008-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4314/EAJSCI.V2I1.40365","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70512634","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Farmers Perceptions on the Productivity of Water in Agriculture: A Case Study at Debre Kidane Watershed, Eastern Tigray, Ethiopia","authors":"N. Tadesse, E. Bekelle","doi":"10.4314/EAJSCI.V2I1.40366","DOIUrl":"https://doi.org/10.4314/EAJSCI.V2I1.40366","url":null,"abstract":"Awareness of the knowledge of farmers on the productivity of water in agriculture (PWA) is the basis for all irrigation activities. This paper assesses the current knowledge level of farmers towards PWA in the Debre Kidane watershed which is located in eastern Tigray. It also identifies obstacles regarding the spread of knowledge of PWA and indicates the best knowledge-disseminating strategies and tools for raising awareness about PWA. Data for the study was obtained from a formal household questionnaire survey, key informant discussion and direct observations of farmers' fields. In the study area, the concept of PWA is new. All the farmers measure the crop harvested but not the volume of water used to produce it. Almost none of the irrigators know when their crop needs water and when to stop irrigating their crop. Howev er, farmers are keen todiscover methods which could help them to produce more crops per drops of water. Consequently, farmers indicated that training is the most suitable knowledge-sharing strategy for creating awareness about PWA, and its absence is the barrier that hinders them from recording PWA. Furthermore, they pointed out that training given through demonstration is their method of preference. Most of the farmers irrigate their farmland by checking the availability of the water in their shallow wells and irrigating their crop until the furrow holds up water. For better utilization of the groundwater resources in the area, the farmers have to be introduced to the concept of PWA. Keywords : Groundwater; Knowledge; Productivity; Strategy; Tool. East African Journal of Sciences Vol. 2 (1) 2008: pp. 62-67","PeriodicalId":33393,"journal":{"name":"East African Journal of Sciences","volume":"2 1","pages":"62-67"},"PeriodicalIF":0.0,"publicationDate":"2008-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4314/EAJSCI.V2I1.40366","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70512706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigations on the Effect of Ball Burnishing Parameters on Surface Roughness and Corrosion Resistance of Hsla Dual - Phase Steels","authors":"D. Rao, H. S. Hebbar, M. Komaraiah, U. N. Kempaiah","doi":"10.4314/EAJSCI.V2I2.40377","DOIUrl":"https://doi.org/10.4314/EAJSCI.V2I2.40377","url":null,"abstract":"Surface finish has a vital influence on most functional properties of a component, such as fatigue strength, wear resistance and corrosion resistance. This has led to processes such as lapping, honing, and burnishing. Burnishing is a fine finishing operation involving the cold working and plastic deformation of surface layers to enhance the surface integrity and the functional utility of a component. This study has been carried out to establish the effect of burnishing parameters, i.e. feed rate, speed, force, ball diameter and lubricant on surface roughness and corrosion resistance of HSLA dual – phase steel specimens. The result indicates that burnishing parameters have a significant effect on surface roughness and corrosion resistance. Keywords : Hardness; Burnishing; Factorial Design; Inter-Critical Temperature East African Journal of Sciences Vol. 2 (2) 2008: pp. 164-169","PeriodicalId":33393,"journal":{"name":"East African Journal of Sciences","volume":"2 1","pages":"164-169"},"PeriodicalIF":0.0,"publicationDate":"2008-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70513082","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development and Performance Evaluation of Indigenously Made Cooling Chambers for Extending the Shelf Life of Mangoes and Sweet Oranges","authors":"D. Debela, Fekedau Lemessa, H. Ravishankar","doi":"10.4314/EAJSCI.V1I2.40351","DOIUrl":"https://doi.org/10.4314/EAJSCI.V1I2.40351","url":null,"abstract":"A study was conducted to develop, construct and evaluate the performance of cooling chambers made from factory pressed burnt clay (structure-1), locally molded mud blocks (structure-2) and wood wall (structure-3) for extending the shelf life of mangoes and sweet oranges. It was observed that structure-1 significantly (p𕟨.05) registered low temperature and high relative humidity over structure-2 and structure-3. Significant lower physiological loss (p𕟨.05) in weight (PLW) was observed in commodities stored under structure-1 due to the low temperature and high RH probably arising from the low vapor pressure. Structure-2 registered significantly (p𕟨.05) low PLW as compared to structure-3 attributable to the differences in wall thickness. Total soluble solids increased as storage time progressed. The rate of increment, however, was significantly lower in mangoes stored under structure-1 as compared to the other chambers. The juice content of the commodities decreased over time irrespective of cooling chambers. The rate of reduction in juice content was, however; significantly lower in structure-1 than the other two. Keywords : Cooling-Chamber; Mango; Shelf-life; Sweet-Orange East African Journal of Sciences Vol. 1 (2) 2007: pp. 127-135","PeriodicalId":33393,"journal":{"name":"East African Journal of Sciences","volume":"1 1","pages":"127-135"},"PeriodicalIF":0.0,"publicationDate":"2007-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4314/EAJSCI.V1I2.40351","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70512535","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enclosures to Enhance Woody Species Diversity in The Dry Lands of Eastern Tigray, Ethiopia","authors":"Emiru Birhane, D. Teketay, P. Barklund","doi":"10.4314/EAJSCI.V1I2.40352","DOIUrl":"https://doi.org/10.4314/EAJSCI.V1I2.40352","url":null,"abstract":"Vegetation and soil seed banks were studied in exclosures and unprotected areas, to investigate the role of exclosures in the rehabilitation of degraded drylands. Woody vegetation was assessed in fifty plots in exclosures and 30 in unprotected areas, each measuring 20 × 20 m². Twenty-seven woody species representing eighteen families were observed in exclosures and fourteen woody species representing twelve families were\u0000recorded in open area. Higher abundance, density and basal area were found in the exclosure. An expanding population structure in exclosure, and obstructed population structure in open area, showed favorable succession in the set-aside area. In both cases, woody species were absent in the soil seed bank. Keywords : Degradation; Natural Regeneration; Rehabilitation; Soil Seed Bank East African Journal of Sciences Vol. 1 (2) 2007: pp. 136-147","PeriodicalId":33393,"journal":{"name":"East African Journal of Sciences","volume":"1 1","pages":"136-147"},"PeriodicalIF":0.0,"publicationDate":"2007-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4314/EAJSCI.V1I2.40352","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70512549","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Concerns on Mismatches between Environments of Selection and Production of Crop Varieties in Ethiopia","authors":"G. Keneni","doi":"10.4314/EAJSCI.V1I2.40347","DOIUrl":"https://doi.org/10.4314/EAJSCI.V1I2.40347","url":null,"abstract":"Crop production plays a significant role in the Ethiopian economy. The sub-sector's output has, however, been very low partially due to the biophysical challenges constraining productivity in smallholder farms and inadequate technological interventions. Genetic modification of crops to improve productivity is preferred to the continual manipulation of the growing environment because of cost particularly to the large majority of resource-poor farmers who cannot afford for production inputs. Consideration of varietal selection vis-a-vis\u0000actual target production environment is vital to maximizing gains from breeding efforts. The tradition across most of the breeding programs in Ethiopia is to develop varieties under optimum management despite the fact that marginal management characterizes the ultimate target production environments. Whether selection under optimum management is likely to result in better productivity gain than under the actual target production\u0000environments is a crucial issue in varietal development. This paper discusses the logical framework for breeding success and the conventional approach to varietal selection and its challenges in Ethiopia. Based on the analyses, the paper proposes that the wheel of the current variety development schemes should be redirected and made more objective and focused towards better serving the major target beneficiaries, i.e. the resource-poor farmers. Keywords : Direct Selection; Indirect Selection; Selection Environment; Target Environment East African Journal of Sciences Vol. 1 (2) 2007: pp. 93-103","PeriodicalId":33393,"journal":{"name":"East African Journal of Sciences","volume":"1 1","pages":"93-103"},"PeriodicalIF":0.0,"publicationDate":"2007-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4314/EAJSCI.V1I2.40347","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70512371","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterization and Fertility Status of the Soils of Ayehu Research Substation, Northwestern Highlands of Ethiopia","authors":"G. Fisseha, H. Gebrekidan","doi":"10.4314/EAJSCI.V1I2.40354","DOIUrl":"https://doi.org/10.4314/EAJSCI.V1I2.40354","url":null,"abstract":"The pedogenic properties and fertility status of the soils at Ayehu Substation of the Amhara Region Agricultural Research Institute were studied both in the field and through laboratory analysis. On the basis of in situ description of two soil profiles and laboratory analysis, the soils of the study site qualified for the Nitisol soil group as\u0000per the FAO/UNESCO Soil Grouping System. The soils were moderately acidic in reaction and silty clay to clay in texture. The pedons exhibited increasing clay contents with depth qualifying for argillic (Bt) horizons. The surface horizons of both pedons revealed the lowest and the bottom (Bt3) horizons indicate the highest bulk density values. The consistent increase of bulk density with depth is apparently due to the decreasing level of organic carbon (OC) with depth from 2.6 to 0.6% in pedon 1 and from 2.8 to 1.1% in pedon 2. The lowest total porosity (44.2%) was observed in the Bt3 horizon of pedon 1 and the highest (55.2%) in the composite surface soil collected around pedon 2. Throughout the depths of the two pedons and surface soil samples, pH (H 2 O) values were higher than pH (KCl) resulting in positive ΔpH values and indicating the presence of variable charge clay surfaces. The subsoil horizons showed lower values of cation exchange capacity (CEC) and percentage base saturation suggesting intensive weathering and presence of 1:1\u0000(kaolinitic) clay minerals. The quantity of exchangeable Na was trace whilst appreciable amount of exchangeable K was available in both pedons. The surface horizons contained high exchangeable Ca and Mg to the extent that the sum of these bases occupied over 83% of the CEC in both pedons. In accordance with OC, total N decreased with depth\u0000from 0.19 to 0.05% in pedon 1 and from 0.22 to 0.10% in pedon 2. The highest contents of Olsen P (3.21 mg l -1 ) and Bray P (4.40 mg l -1 ) were obtained in the surface horizon of pedon 1 and both showed decreasing trends with depth in\u0000the two pedons. Application of increasing rates of P fertilizer increased both the Olsen and Bray II P consistently, while applied rates of N did not bring significant change in soil total N content. Keywords : Ayehu Area; Bray II Available P; Nitisols; Olsen Available P; Pedon East African Journal of Sciences Vol. 1 (2) 2007: pp. 160-169","PeriodicalId":33393,"journal":{"name":"East African Journal of Sciences","volume":"1 1","pages":"160-169"},"PeriodicalIF":0.0,"publicationDate":"2007-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4314/EAJSCI.V1I2.40354","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70512612","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Response of Anchote (Coccinia Abyssinica) to Organic and Inorganic Fertilizers Rates and Plant Population Density in Western Oromia, Ethiopia","authors":"G. Abera, H. Guteta","doi":"10.4314/EAJSCI.V1I2.40350","DOIUrl":"https://doi.org/10.4314/EAJSCI.V1I2.40350","url":null,"abstract":"A comparative study of organic and inorganic fertilizer, and intra-row and inter-row spacing experiments were conducted at Bako Agricultural Research Center for three consecutive years (2002-2004) to determine optimum nutrient supply and plant population, respectively, for anchote production. The experiments were laid out in a randomized complete block design with three replications. The fertilizer study consisted of four nitrogen levels: 0, 46, 92 and 138 kg N ha -1 and three phosphorous levels: 0, 20 and 40 kg Pha -1 in a factorial arrangement along with farmyard manure (FYM) at rates of 5, 8 and 10 t ha -1 . The spacing study was conducted using three intra-rows: 10, 20 and 30 cm and four inter rows: 40, 60, 80 and 100 cm. Analysis of variance showed highly significant difference among N rates with respect to root length and root yield. Similarly, P and FYM supply resulted in highly significant difference in root yield. Apparently, application of 5 and 8 t ha -1 FYM resulted in an improved root yield of 44% and 63% over control, respectively. The supply of FYM was found to be superior over inorganic fertilizer supply perhaps due to its merits in improving soil structure, organic matter and enhancement of nutrient uptake. Intra-row spacing affected root yield highly and significantly while inter row spacing affected root yield and average root weight per plant. The reduction of intra-row spacing from 30 cm to 10 cm resulted in increase of total tuberous root yield by 137%. Reduction of inter row spacing from 100 cm to 40 cm resulted in high total tuberous root yield by 37.4%. From the present findings, therefore, 5-8 t ha -1 FYM or 46/20 kg ha -1 N/P and 40-60 cm inter row and 10 cm intra-row spacing are recommended for high yield of anchote production and enhancement of soil structure and its nutrient contents for the western sub-humid zones of Oromia, Ethiopia. Keywords : Anchote; Farm Yard Manure; Inorganic Fertilizer; Root Yield; Spacing East African Journal of Sciences Vol. 1 (2) 2007: pp. 120-126","PeriodicalId":33393,"journal":{"name":"East African Journal of Sciences","volume":"1 1","pages":"120-126"},"PeriodicalIF":0.0,"publicationDate":"2007-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4314/EAJSCI.V1I2.40350","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70512504","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}