Sinet, Ethiopian Journal of Science最新文献

{"title":"Demonstrating close-packing of atoms using spherical bubble gums","authors":"Z. Gebeyehu, R. B. Dabke","doi":"10.4314/SINET.V37I1","DOIUrl":"https://doi.org/10.4314/SINET.V37I1","url":null,"abstract":"In this paper, the use of spherical bubble gums (Gum Balls) to demonstrate the close-packing of atoms and ions is presented. Spherical bubble gums having distinctive colours were used to illustrate the different layers in variety of crystalline packing and the formation of tetrahedral and octahedral holes. Students with hands-on experience of building the different packing models could better understood the close-packing of atoms.","PeriodicalId":245987,"journal":{"name":"Sinet, Ethiopian Journal of Science","volume":"142 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113989067","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":"Infection Site Dependent Progression of Cutaneous Lesions in African Green Monkeys (Cercopithecus aethiops) Experimentally Infected with Leishmania aethiopica Promastigotes","authors":"Menberework Chanyalew, Asrat Hailu","doi":"10.4314/SINET.V36I1","DOIUrl":"https://doi.org/10.4314/SINET.V36I1","url":null,"abstract":"Studies on experimental infection of Leishmania aethiopica are very limited due to lack of laboratory animal models. It was previously reported that the African green monkey (grivet monkey) could serve as a non–human primate model of L. aethiopica infection. This report provides preliminary data on the development and progression of skin lesions in grivet monkeys when infected with L. aethiopica either in the eye lids or the tip of nose. A total of 22 African green monkeys were inoculated subcutaneously on the eye lid (n=14) or the tip of nose (n=8) with 5 x 10 6 stationary phase promastigotes of L. aethiopica . No lesions developed on the eye lids. Lesions of various stages of cutaneous leishmaniasis were observed at the tip of nose. The outcome of L. aethiopica infection in African green monkeys and possibly humans could be infection-site dependent. Further studies are needed to examine and understand the immunopathogenetic processes.","PeriodicalId":245987,"journal":{"name":"Sinet, Ethiopian Journal of Science","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123711710","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":"A preliminary survey of Erythrocebus patas in Anbesa Chaka, Bambesi Woreda of Benishangul-Gumuz Region, western Ethiopia","authors":"S. Yirga, Manyingerew Shenkut, Mezgebu Ashagrie, D. Sertse","doi":"10.4314/SINET.V33I1.71515","DOIUrl":"https://doi.org/10.4314/SINET.V33I1.71515","url":null,"abstract":"A preliminary survey conducted in Benishangul-Gumuz Region, Bambesi Woreda from late January to early February, 2010 resulted in finding two groups of the same taxon of patas monkeys. Each of the two groups had one adult male, and one of them consisted of 33 individuals, where as the other had a total of 23 individuals including the adult males, adult and sub-adult females and infants. The survey was conducted on foot and by a vehicle and behavioural data were collected using adlibtum method. From the structure of the two groups and the season during which they probably had their newborns, they belong to the species Erythrocebus patas which are also found elsewhere. However, the long black fur coloration along the shoulder, back and upper fore limbs of the males is different from any of the four different subspecies, namely, E . patas patas, E. patas villiersi, E. patas pyrrhonotus and E. patas baumstarki, and others found in Athi plains, southeast of Nairobi and east of the rift valley, which have pink faces and a blue nasal spot and not given subspecific names. Thus, it is reasonable to think of the Benishangul patas as subspecies, as they are distinct from the other subspecies.","PeriodicalId":245987,"journal":{"name":"Sinet, Ethiopian Journal of Science","volume":"113 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126698470","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":"Assessment of slope stability and remedial measures around Gilgel Gibe-II Hydroelectric Project, Southwest Ethiopia","authors":"Engdawork Mulatu, T. Raghuvanshi, B. Abebe","doi":"10.4314/SINET.V33I1.70560","DOIUrl":"https://doi.org/10.4314/SINET.V33I1.70560","url":null,"abstract":"A road constructed from Fofa town to Gilgel Gibe-II powerhouse in south-western Ethiopia passes through an extremely rugged terrain characterized by steep hill slopes and deep valleys. The present study has been carried out to identify potentially unstable slope sections and to work out proper remedial measures. In order to identify potential unstable slopes in the study area field investigations for slope stability analysis were undertaken. Further, based on the field manifestations of instabilities eight potentially unstable slopes were identified. Out of these, seven slope sections show potential for planar mode of failure whereas, one slope shows a potential for wedge mode of failure. The detailed stability study of these critical slope sections has been carried out by limit equilibrium method. The slopes having planar mode of failure were analyzed by using Sharma et al. (1995) technique, whereas the slope having wedge mode of failure was analyzed by ‘SASW’ computer program. The stability analysis was carried out for the existing and anticipated worst conditions. The results indicate that all critical slopes in the study area are stable for the existing conditions, represented by dry static conditions whereas for the anticipated worst conditions ( i.e. , moderately saturated slope with dynamic ground condition) slopes may become unstable. Based on the results of the stability condition, suitable remedial measures, such as safe cut slope design, rock bolt anchoring and suitable drainage requirements have been worked out for the critical slope sections.","PeriodicalId":245987,"journal":{"name":"Sinet, Ethiopian Journal of Science","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121716150","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":"Evaluation of indigenous fungal isolates and Metarhizium anisopliae var. acriidum against adult lesser wax moth, Achroia grisella (l) (Pyralidae: Lepidoptera)","authors":"E. Seyoum, H. Namusana","doi":"10.4314/SINET.V33I1.70751","DOIUrl":"https://doi.org/10.4314/SINET.V33I1.70751","url":null,"abstract":"The lesser wax moth (LWM) is a widely distributed and devastating insect pest to the honey production sector in Ethiopia. The present study aimed at investigating the potential of native fungal isolates against the lesser wax moth and assessing non target effect of one isolate of Beauveria (IITA 18) and five isolates of Metarhizium (IMI 330189, DLCO-AA83, DLCO-AA 109, DLCO-AA5, DLCO-AA14) via inoculating Ethiopian honeybee race, Apis mellifera bandasii . The effects of these six fungal isolates were evaluated in the laboratory for their pathogenicity to adult lesser wax moths. Spore dilutions were prepared in 0.5% Tween 80. Adults were treated by spraying 2 ml of conidial suspensions ranging from 2x10 4 to 2x10 7 conidia/ml. Adult lesser wax moths were found to be susceptible to all isolates and concentrations used. Comparison of post-treatment mortality of adult, lesser wax moth (LWM) at the lowest concentration (2x10 4 conidia/ml) revealed that infection of > 90% could be achieved by day 8 post inoculation. Investigation into effects of mycosis on percentage emergence of adults from fungal treated last instar larvae of the lwm showed no significant difference (P>0.05) between the treated and untreated controls. Laboratory based experiments on the host specificity of the six fugal isolates had no effect in which only 1 individual honeybee (0.5%) was infected with isolate IITA 18 (Beauveria spp.) while isolate DLCO-AA83 (Metarhizium spp.), caused infection in 2 individual honeybees.","PeriodicalId":245987,"journal":{"name":"Sinet, Ethiopian Journal of Science","volume":"110 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117217599","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":"Supplementary value of vetch (Vicia dasycarpa) hay as a replacement to concentrate mix in the diet of lactating crossbred cows","authors":"Getu Kitaw, S. Melaku, E. Seifu, M. Dejene","doi":"10.4314/SINET.V33I1.70739","DOIUrl":"https://doi.org/10.4314/SINET.V33I1.70739","url":null,"abstract":"An 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 (T 1 ), and replacement of the concentrate mix with vetch ( Vicia dasycarpa ) hay at a level of 25% (T 2 ), 50% (T 3 ) and 75% (T 4 ). 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) among treatments, except for cows in T 3 that had higher (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.","PeriodicalId":245987,"journal":{"name":"Sinet, Ethiopian Journal of Science","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131398869","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":"Embryogenic callus induction and regeneration in anther culture of noug (Guizotia abyssinica (L.F) Cass.)","authors":"Misteru Tesfaye, T. Feyissa, Likyelesh Gugsa","doi":"10.4314/SINET.V33I1.71512","DOIUrl":"https://doi.org/10.4314/SINET.V33I1.71512","url":null,"abstract":"Two released noug varieties, Shambu and Fogera, were used for this experiment. Initially, two experiments were conducted to identify the appropriate morphological stage of capitula (buds) for harvesting maximum number of responsive anthers and to study the optimum cold pretreatment duration for callus induction from the anthers. Three culture media, MS, B 5 and NN, were employed for callus induction. MS medium, with nine different combinations of KN and IAA, was used for shoot regeneration study. Three different concentrations of IBA and growth regulator-free MS medium were used for the rooting experiment. The results showed that capitula, fully or slightly covered by sepal having whitish-green or greenish-yellow anthers, were the optimum stages of harvesting capitula; callus was efficiently induced when the capitula were pre-treated at 4 ° C for 24 hours. The types of calli induced significantly (P≤0.05) varied among the three media. Embryogenic calli were mainly produced in NN and B 5 media, while varying in texture and colour. High percentage of embryogenic calli (80%) was induced on NN medium from the variety Shambu, followed by b 5 medium showing 40% inductions for both varieties. Among nine different KN and IAA combinations, 2 mg/l KN combined with 1 mg/l IAA, was the most efficient for shoot regeneration. It was also found that 0.5 mg/l IBA was optimum for root induction. In the growth room as well as in the glasshouse, the survival rate of regenerants was generally better for the variety Shambu than for Fogera.","PeriodicalId":245987,"journal":{"name":"Sinet, Ethiopian Journal of Science","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127964675","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":"Provenance of middle Stone Age obsidian artefacts from the central sector of the Main Ethiopian Rift Valley","authors":"A. Negash, F. Brown, M. Alene, B. Nash","doi":"10.4314/SINET.V33I1.70736","DOIUrl":"https://doi.org/10.4314/SINET.V33I1.70736","url":null,"abstract":"The Gademotta/Kulkuletti sites, located in the central part of the Main Ethiopian Rift Valley, represent the earliest Middle Stone Age (MSA) sequences in the country. Here we present the geochemical provenance of obsidian archaeological artefact recovered through excavation at the site. The artefacts and source materials were characterized by EDXRF and electron microprobe. Results show that the artefacts were procured from two sources, one local, and one presumably more distant, implying that despite the local availability of good quality raw material, not all obsidians were procured from a nearby source.","PeriodicalId":245987,"journal":{"name":"Sinet, Ethiopian Journal of Science","volume":"99 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116084239","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":"AN ECOLOGICAL STUDY ON RODENTS OF NATURAL VEGETATION AND FARM LANDS IN SILTIE, CENTRAL ETHIOPIA","authors":"Mulatu Osie, A. Bekele, M. Balakrishnan","doi":"10.4314/SINET.V33I1.71514","DOIUrl":"https://doi.org/10.4314/SINET.V33I1.71514","url":null,"abstract":"An ecological study on species composition, distribution, relative abundance and habitat association of rodents was conducted in Siltie natural vegetation and nearby farmlands during July 2008 - March 2009. Five habitat types, three from natural and two from agricultural fields were randomly selected based on representation of the main vegetation zones. In each habitat type, one representative grid was selected for live trapping. In addition, rodents were also snap-trapped from these habitats. A total of 562 captures was made in 2940 live-trap nights and 87 in 1200 snap-trap nights. Species of small mammals trapped were Mastomys natalensis (33.3%), Arvicanthis dembeensis (23.0%), Mastomys erythroleucus (12.1%), Stenocephalemys albipes (8.4%), Desmomys harringtoni (6.0%), Mus mahomet (5.9%) , Tatera robusta (5.1%) , Lophuromys flavopunctatus (2.8%) , Rattus rattus (2.5%) and Arvicanthis niloticus (0.9%). The trap success varied significantly from habitat to habitat. Population density of rodents was high in the bush land and forest habitats. Plant matters were the most common food items revealed from the stomach contents of snap-trapped individuals. A. dembeensis , M. Mahomet , D. harringtoni and M. natalensis were recorded as major pests in the study area. Breeding was seasonal for most of the species trapped. The number of embryos varied both within and among species.An ecological study on species composition, distribution, relative abundance and habitat association of rodents was conducted in Siltie natural vegetation and nearby farmlands during July 2008 - March 2009. Five habitat types, three from natural and two from agricultural fields were randomly selected based on representation of the main vegetation zones. In each habitat type, one representative grid was selected for live trapping. In addition, rodents were also snap-trapped from these habitats. A total of 562 captures was made in 2940 live-trap nights and 87 in 1200 snap-trap nights. Species of small mammals trapped were Mastomys natalensis (33.3%), Arvicanthis dembeensis (23.0%), Mastomys erythroleucus (12.1%), Stenocephalemys albipes (8.4%), Desmomys harringtoni (6.0%), Mus mahomet (5.9%) , Tatera robusta (5.1%) , Lophuromys flavopunctatus (2.8%) , Rattus rattus (2.5%) and Arvicanthis niloticus (0.9%). The trap success varied significantly from habitat to habitat. Population density of rodents was high in the bush land and forest habitats. Plant matters were the most common food items revealed from the stomach contents of snap-trapped individuals. A. dembeensis , M. Mahomet , D. harringtoni and M. natalensis were recorded as major pests in the study area. Breeding was seasonal for most of the species trapped. The number of embryos varied both within and among species.","PeriodicalId":245987,"journal":{"name":"Sinet, Ethiopian Journal of Science","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132661802","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":"Phosphate fertilizer and weed control effects on growth and yield of field pea on Nitisols of central highlands of Ethiopia","authors":"G. Agegnehu","doi":"10.4314/SINET.V32I2.68860","DOIUrl":"https://doi.org/10.4314/SINET.V32I2.68860","url":null,"abstract":"Soil acidity and the associated low phosphorus availability and poor crop management practices are among the major factors constraining field pea productivity in the highlands of Ethiopia. The effect of phosphate fertilizer and weed control on yield and yield components of field pea ( Pisum sativum L.) were studied on acidic Nitisols of farmers’ fields of Welmera Woreda, West Shoa. Factorial combinations of four levels of phosphate fertilizer (0, 10, 20 and 30 kg P ha -1 ) as triple super-phosphate (TSP) and two levels of weeding (w 0 = no weeding and w 1 = hand weeding once) were laid out in randomized complete block design with three replications. Results indicated that a highly significant positive response of plant height, number of pods per plant, total biomass and grain yields of field pea were noted to phosphate fertilizer and weeding treatments. Application of phosphate fertilizer at the rates of 10, 20 and 30 kg P ha -1 increased mean grain yields of field pea by 36, 67 and 57%, respectively compared to the control. Weeding once by hand increased mean grain yield of field pea by 15% compared to the unweeded check. The interaction between applied phosphate fertilizer and weed control (P×W) significantly affected field pea grain yield and total biomass. Grain yield was very significantly and positively correlated with plant height, number of pods per plant and total biomass (r = 0.59 ** , 0.68 *** and 0.94 *** , respectively). The results of economic analysis indicated that the treatment with application of 20 kg P ha -1 and weeding once during the 4 th week after sowing by hand was identified to be the best option with a marginal rate of return of 277%, well above the minimum acceptable rate of return of 100%, which is economically the most feasible alternative.","PeriodicalId":245987,"journal":{"name":"Sinet, Ethiopian Journal of Science","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122920557","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}