Sinet, Ethiopian Journal of Science最新文献_第8页

TOXICITY OF CASSAVA WASTEWATER EFFLUENTS TO AFRICAN CATFISH: CLARIAS GARIEPINUS (BURCHELL, 1822) 木薯废水对非洲鲶鱼的毒性研究:clarias gariepinus (burchell, 1822)

Sinet, Ethiopian Journal of Science Pub Date : 2006-04-12 DOI: 10.4314/SINET.V28I2.18254

S. Adewoye, O. Fawole, O. Owolabi, J. Omotosho

{"title":"TOXICITY OF CASSAVA WASTEWATER EFFLUENTS TO AFRICAN CATFISH: CLARIAS GARIEPINUS (BURCHELL, 1822)","authors":"S. Adewoye, O. Fawole, O. Owolabi, J. Omotosho","doi":"10.4314/SINET.V28I2.18254","DOIUrl":"https://doi.org/10.4314/SINET.V28I2.18254","url":null,"abstract":"The relative lethal and sublethal toxicity of cassava wastewater effluents from a local food factory were investigated on Clarias gariepinus fingerlings using a renewable static bioassay. The physico-chemical characteristics of the cassava wastewater effluents showed a number of deviations from the standards of the Federal Environmental Protection Agency (FEPA) on the guidelines for effluent discharges. Considering the pollutants of the effluent, cyanide (CN) is suspected to be primarily responsible for the toxicity, although synergistic effect of other pollutants cannot be ruled out. At each exposure, in the two tests, the test-organisms showed signs of serious stress, swimming pattern changed and mortality increased over relatively small increase in concentration. The LC 50 for lethal and sublethal tests were 0.024 mg1 -1 and 0.0064 mg1 -1 , respectively. The differences observed in the mortalities and bioconcentration of metals in fish muscles of varying concentrations were significant (p Keywords : bioconcentration, Clarias gariepinus , effluent, toxicity, wastewater SINET: Ethiopian Journal of Science Vol. 28(2) 2005: 189-194","PeriodicalId":245987,"journal":{"name":"Sinet, Ethiopian Journal of Science","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122493445","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}

引用次数: 38

Maturation, sex ratio and fecundity of the Nile perch lates niloticus (L.) (pisces: centropomidae) in Lake Chamo, Ethiopia 埃塞俄比亚查莫湖尼罗河鲈鱼的成熟、性别比例和繁殖力(双鱼座:拟鱼科)

Sinet, Ethiopian Journal of Science Pub Date : 2006-04-12 DOI: 10.4314/SINET.V28I2.18251

E. Dadebo, I. Ahlgren, G. Ahlgren

{"title":"Maturation, sex ratio and fecundity of the Nile perch lates niloticus (L.) (pisces: centropomidae) in Lake Chamo, Ethiopia","authors":"E. Dadebo, I. Ahlgren, G. Ahlgren","doi":"10.4314/SINET.V28I2.18251","DOIUrl":"https://doi.org/10.4314/SINET.V28I2.18251","url":null,"abstract":"Length-weight relationship, length at first maturity and sex ratio of the Nile perch Lates niloticus (L.) were studied from 342 fish samples collected between February 1995 and May 1996. The relationship between total length (TL ) and total weight (TW) for both sexes was curvilinear and statistically significant. The regression equation for the males was TW=0.0044TL 3.27 (r2=0.978, P<0.001) and that for the females was TW=0.0058TL 3.2 (r 2 =0.991, P<0.001). 50% maturity size of males and females were found to be 88 cm and 106 cm TL respectively. The overall male to female sex ratio of 1: 0.64 was significantly different from the theoretical 1:1 ratio (χ2=16.0, P<0.001). Generally males were more numerous at smaller size classes while females predominate at larger size classes. Forty-nine fish samples that ranged in length from 106.8 cm to 192 cm TL and in weight from 17,000 g to 108,000 g TW were used in fecundity estimates. The weight of ripe ovaries ranged from 325 g to 5,600 g with the mean weight of 934 g. Fecundity ranged between 1.24 million and 37.44 million eggs. The total and relative mean fecundity of L. niloticus was 6.35 million eggs female -1 and 162 eggs g -1 TW. The average number of eggs g -1 of ovary ranged from 6,200 to 9 ,300 with the mean number of 8 ,100. The relationships between fecundity and TL (F=0.0034TL 4.32, n=49, P<0.01) and fecundity and TW (F=0.4357TW1.55, n=49, P<0.01) were curvilinear while the relationship between fecundity and ovary weight (OW) (F=8,017OW-84,461, n=49, P<0.01) was linear.","PeriodicalId":245987,"journal":{"name":"Sinet, Ethiopian Journal of Science","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127526867","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}

引用次数: 4

Variation and association analyses on morphological characters of linseed ( Linum usitatissimum L.) in Ethiopia 埃塞俄比亚亚麻籽(Linum usitatissimum L.)形态性状变异及关联分析

Sinet, Ethiopian Journal of Science Pub Date : 2006-04-12 DOI: 10.4314/SINET.V28I2.18249

Worku Negash, Zemede Asfaw Z. Asfaw, Haile S. Yibrah

{"title":"Variation and association analyses on morphological characters of linseed ( Linum usitatissimum L.) in Ethiopia","authors":"Worku Negash, Zemede Asfaw Z. Asfaw, Haile S. Yibrah","doi":"10.4314/SINET.V28I2.18249","DOIUrl":"https://doi.org/10.4314/SINET.V28I2.18249","url":null,"abstract":"Morphological studies of linseed ( Linum usitatissimum L.) of Ethiopia were undertaken in this study on 56 accessions collected from 10 administrative regions (former regions) classified into seven altitude classes. The seeds were planted during 2001 growing season in Bale-Goro wereda using randomized complete block design (RCBD) on three replications with the aim of investigating the morphological diversity in the accessions. Over the entire accession, except seed number per boll, all the characters showed significant variation. However, regional groups of linseed accessions showed insignificant variations only for secondary branches number per plant (SBP), days to flowering (DTF) and days to maturity (DTM) among themselves, and altitudinal groups of linseed accessions only for seed number per boll (SNB) and days to flowering (DTF). The analysis for coefficient of variation and cluster analysis showed that accessions from Gojam and Tigray were less diversified. About 53% of the total associations showed significant correlation and out of this 71% of the correlations were with the positive significant correlation coefficients. Cluster analysis indicates that accessions collected from the two extremes of altitude classes have variations for the studied traits. It is only Tigray Region that did not contribute member accession to cluster III, whereas Gondar and Bale regions contribute member accessions to 80% of clusters. Factor analysis showed that of the total variation (73.86%) 30.04% and 27.29% were accounted for by first and second principal components, respectively. The highest Shannon diversity index (0.322 ± 0.039) was recorded for boll size and Shannon diversity index for overall pooled mean was 0.223 ± 0.063. Keywords : cluster/factor analysis, diversity index, linseed accessions, morphological characters, variation/association SINET: Ethiopian Journal of Science Vol. 28(2) 2005: 129-140","PeriodicalId":245987,"journal":{"name":"Sinet, Ethiopian Journal of Science","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127775953","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}

引用次数: 11

Changes in soil carbon and total nitrogen following reforestation of previously cultivated land in the highlands of Ethiopia 埃塞俄比亚高地以前耕地重新造林后土壤碳和总氮的变化

Sinet, Ethiopian Journal of Science Pub Date : 2006-04-12 DOI: 10.4314/SINET.V28I2.18245

M. Lemenih, Bekele Lemma, D. Teketay

{"title":"Changes in soil carbon and total nitrogen following reforestation of previously cultivated land in the highlands of Ethiopia","authors":"M. Lemenih, Bekele Lemma, D. Teketay","doi":"10.4314/SINET.V28I2.18245","DOIUrl":"https://doi.org/10.4314/SINET.V28I2.18245","url":null,"abstract":"Changes in soil C and total N stocks were investigated following reforestation of previously cultivated soil in comparison with soil subjected to continuous cultivation and soil under an adjacent natural forests in south central highlands of Ethiopia. Two of the most widely planted tree species in the highlands of Ethiopia, namely Eucalyptus saligna and Cupressus lusitanica , were considered in the plantation treatments. Soil C and total N contents in the upper 0–10 and 10–20 cm soil layers were significantly different in the order: Natural forest > C. lusitanica > E. saligna > Farmland. Differences in soil C and total N contents among the sites for soil depths greater than 20 cm were negligibly small and statistically not significant. Soil C and total N stocks in the upper 0.80 m mineral soil also varied significantly in the same order as above. Estimated average annual soil C accruals were 156 and 37 g C m -2 yr -1 for Cupressus lusitanica and Eucalyptus saligna , respectively. The results demonstrate that reforestation of former arable soils in the dry Afromontane region of Ethiopia could yield significant restoration of soil C and total N that are lost in the process of natural forest conversion into arable lands and subsequent cultivation. However, the two plantation species differed considerably with respect to the rate of soil C and total N accrual. This suggests that proper selection of tree species will considerably affect the magnitude and rate of soil C sequestration. Keywords : continuous farming, Cupressus lusitanica , Eucalyptus saligna , soil carbon sequestration, soil carbon loss SINET: Ethiopian Journal of Science Vol. 28(2) 2005: 99-108","PeriodicalId":245987,"journal":{"name":"Sinet, Ethiopian Journal of Science","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124975552","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}

引用次数: 19

Quantitative genetic analysis of total glucosinolate, oil and protein contents in Ethiopian mustard ( Brassica carinata A. Braun) 埃塞俄比亚芥菜(Brassica carinata A. Braun)总硫代葡萄糖苷、油和蛋白质含量的定量遗传分析

Sinet, Ethiopian Journal of Science Pub Date : 2006-04-12 DOI: 10.4314/SINET.V28I2.18250

N. Alemayehu, H. Becker

{"title":"Quantitative genetic analysis of total glucosinolate, oil and protein contents in Ethiopian mustard ( Brassica carinata A. Braun)","authors":"N. Alemayehu, H. Becker","doi":"10.4314/SINET.V28I2.18250","DOIUrl":"https://doi.org/10.4314/SINET.V28I2.18250","url":null,"abstract":"Cultivars of Ethiopian mustard are agronomically robust, but have very high levels of total glucosinolates, which impair feed value of the meal though it is rich in protein of balanced amino acids. This experiment was undertaken to assess the level of natural variation in total glucosinolate, and study its inheritance together with that of oil and protein from a diallel cross of six inbred lines which were field-tested in a randomized block design at two locations in Ethiopia. Seeds were analyzed using HPLC (glucosinolates), NMR (oil) and NIRS (protein). Analyses of variance, Hayman's method of diallel analysis and a mixed linear model of genetic analysis were employed to estimate and predict genetic parameters and interactions. There were significant differences among the parental lines as well as their hybrids. The additive, dominance and cytoplasmic effects were highly significant for all the traits. The additive component of variance, accounting for about 40% of the total variations in all the traits, was twice as much as the dominance, which in turn was also about twice as much as the variation accounted by the cytoplasm. A clear-cut case of inbreeding depression was evident with oil content. Partial dominance was most prevalent in governing total glucosinolate although some levels of over-dominance were also noticed. It appeared that in addition to nuclear genes, cytoplasmic components, which could be persistent or transient maternal effects, are also of significance in the inheritances of these quantitative traits in B. carinata . There were at least two dominant genes with decreasing effect on total glucosinolate for every single recessive gene of counter actions. The predominant additive component of variation coupled with the high narrow-sense heritability may allow fixation of low levels of total glucosinolate in recombinant inbred lines by selection. Keywords : Brassica carinata , diallel cross, glucosinolates, oil, protein SINET: Ethiopian Journal of Science Vol. 28(2) 2005: 141-150","PeriodicalId":245987,"journal":{"name":"Sinet, Ethiopian Journal of Science","volume":"161 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121691506","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}

引用次数: 11

Major ions composition of the groundwater and surface water systems and their geological and geochemical controls in the Ethiopian volcanic terrain 埃塞俄比亚火山地带地下水和地表水系统的主要离子组成及其地质和地球化学控制

Sinet, Ethiopian Journal of Science Pub Date : 2006-04-12 DOI: 10.4314/SINET.V28I2.18253

T. Ayenew

{"title":"Major ions composition of the groundwater and surface water systems and their geological and geochemical controls in the Ethiopian volcanic terrain","authors":"T. Ayenew","doi":"10.4314/SINET.V28I2.18253","DOIUrl":"https://doi.org/10.4314/SINET.V28I2.18253","url":null,"abstract":"Broad hydrochemical survey has been carried out to study the spatial variation of the major ions composition of the surface and groundwater systems in the Ethiopian volcanic terrain and associated Plio-Quaternary sediments. The result revealed wide hydrochemical variations controlled by geological, geochemical, geomorphological and climatological factors. The total ionic concentration increases dramatically from the highlands towards the rift valley following the regional groundwater flow directions to low-lying regions characterized by low annual rainfall and high evapotranspiration. In the rift the total dissolved solids (TDS) variation is dramatic (in places more than 50 fold). The highland waters are predominantly fresh with low total ionic concentrations, TDS varying often from 50 to 1200 mg/l; with dominant ions of Ca, Mg and HCO 3 . The rift valley waters have very high TDS (varying in a wide range between 200 and 73,015 mg/l) characterized by high Na and HCO3, in places highly enriched with F. Waters of the southern and central Main Ethiopian Rift (MER) are dominated by HCO 3 tending to SO 4 and Cl type in northern and central Afar mainly due to changes in lithology related to evaporite deposits and due to the natural chemical evolution of waters as they move from highland recharge to low-lying rift discharge areas. Deep geothermal waters, alkaline terminal lakes of the MER and small highly evaporated saline and brackish lakes of the Afar have the highest ionic concentrations. Keywords : Ethiopian rift, hydrogeology, ionic concentration, TDS, volcanic terrain SINET: Ethiopian Journal of Science Vol. 28(2) 2005: 171-188","PeriodicalId":245987,"journal":{"name":"Sinet, Ethiopian Journal of Science","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122240853","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}

引用次数: 54

Water stress affects the germination, emergence, and growth of different sorghum cultivars 水分胁迫影响不同高粱品种的萌发、出苗和生长

Sinet, Ethiopian Journal of Science Pub Date : 2006-04-12 DOI: 10.4314/SINET.V28I2.18248

W. Bayu, N. Rethman, P. Hammes, P. Pieterse, J. Grimbeek, M. V. D. Linde

{"title":"Water stress affects the germination, emergence, and growth of different sorghum cultivars","authors":"W. Bayu, N. Rethman, P. Hammes, P. Pieterse, J. Grimbeek, M. V. D. Linde","doi":"10.4314/SINET.V28I2.18248","DOIUrl":"https://doi.org/10.4314/SINET.V28I2.18248","url":null,"abstract":"Two experiments were conducted to study the effects of water deficit stress on the germination, emergence and seedling growth of sorghum [ Sorghum bicolor (L.) Moench] using Completely Randomised Block Design in four replications. Five sorghum cultivars (Jigurti, Gambella 1107, Meko, 76 T1 #23 and P9403) were evaluated under three water deficit stress treatments (0, -0.20 and -0.85 MPa) using PEG as an osmoticum (Experiment I) and under four varying growing media water contents (100, 60, 40 and 20% of field capacity) using sand (Experiment II). In both experiments, water deficit stress significantly reduced the rate and percentage of germination and emergence and early seedlings growth. Coleoptile, mesocotyl, radicle, and seedling shoot and root lengths, as well as root area were adversely affected by water deficit stress. Cultivars differed in the rate and percentage of germination, and emergence and seedling growth. Gambella 1107, Meko and P9403 had significantly (P Keywords : emergence, germination, seedling growth, sorghum, water deficit SINET: Ethiopian Journal of Science Vol. 28(2) 2005: 119-128","PeriodicalId":245987,"journal":{"name":"Sinet, Ethiopian Journal of Science","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133004405","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}

引用次数: 13

Vegetation of Chencha Highlands in Southern Ethiopia 埃塞俄比亚南部钦查高地的植被

Sinet, Ethiopian Journal of Science Pub Date : 2006-04-12 DOI: 10.4314/SINET.V28I2.18247

Desalegn Wana, Z. Woldu

引用次数: 19

GEOMAGNETIC SECULAR VARIATION AND THE 1969-1970 SECULAR JERK AT THE AFRICAN OBSERVATORIES 地磁长期变化和1969-1970年非洲天文台的长期扰动

Sinet, Ethiopian Journal of Science Pub Date : 2005-10-18 DOI: 10.4314/SINET.V27I2.18233

T. Haile

{"title":"GEOMAGNETIC SECULAR VARIATION AND THE 1969-1970 SECULAR JERK AT THE AFRICAN OBSERVATORIES","authors":"T. Haile","doi":"10.4314/SINET.V27I2.18233","DOIUrl":"https://doi.org/10.4314/SINET.V27I2.18233","url":null,"abstract":"All-day annual mean values of the D, H and Z components of the geomagnetic field from ten observatories in the African continent are used to study long period secular variations, effects of external signals for the variation in the recorded field and for the signatures of geomagnetic jerks in the African region. Polynomials of second or third degree are found to be adequate to represent the secular variation in the field for most of the observatories. This shows that no strong local anomalies exist over much of the continent and the source of the secular variation is deep seated. Departures from these trends are observed over the Southern African region. The residuals in the geomagnetic field components are shown to exhibit parallelism with the periods corresponding to the double solar cycle only for some of the stations. A clear latitudinal distribution in the geomagnetic component that exhibits the 1969–70 secular jerk is shown. The jerk appears in the plots of the first differences in H for the southern most observatories of Hermanus, Hartebeesthoek, and Tsumeb, while the Z plots show the jerk for near equatorial and equatorial stations of Antananarivo, Luanda Belas, Bangui and Addis Ababa. There is some indication for this jerk in the first difference plots of D for the northern stations of M'Bour and Tamanrasset. The plots of D rather strongly suggest the presence of a jerk around 1980 at most of the stations. Key words/phrases : Magnetic observatories, polynomial fitting, residuals, secular variation, secular jerk SINET: Ethiopian Journal of Science Vol. 27 (2) 2004: 105–120","PeriodicalId":245987,"journal":{"name":"Sinet, Ethiopian Journal of Science","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131297525","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}

引用次数: 1

Isozymes, protein and ODAP variability of grasspea (Lathyrus sativus L.) in Ethiopia 埃塞俄比亚草种(Lathyrus sativus L.)同工酶、蛋白质和ODAP变异

Sinet, Ethiopian Journal of Science Pub Date : 2005-10-18 DOI: 10.4314/SINET.V27I2.18246

W. Tadesse, E. Bekele

引用次数: 3