检索结果-南通市图书馆

A Technical Note: Orientation of Cracks and Hydrology in a Shrink-Swell Soil

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Soil Science 2012年第2期2卷 91-94页

Crack orientations are an im.ortant soil physical property that affects water flow, particularly in vertic soils. However, the spatial and tem.oral variability of crack orientations across different land uses and gilgai features is not well-docum.nted and addressed in hydrology m.dels. Thus;there is a need to quantify crack orientations for different land uses and to incorporate their spatial and tem.oral dynam.cs into hydrological m.dels. Our objectives were to docum.nt the spatial variability of cracks orientations across two land uses and to dem.nstrate the potential im.ortance of crack orientation related to the hydrology of Vertisols. The exploratory field m.asurem.nts of the spatial distribution of crack orientations across two Vertisol catenae of two land uses and gilgai features are presented. The field survey showed the com.lexity of crack geom.try in a field, the potential im.act of crack orientation on Vertisol hydrology and the challenges associated with m.asurem.nt of crack orientations.

关键词： Crack Orientation Hydrology

Differential Responses of Electrolyte Leakage and Pigm.nt Com.ositions in m.ize and Sorghum.After Exposure to and Recovery from.Pre- and Post-Flowering Dehydration

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Agricultural Sciences in China 2010年第6期9卷 813-824页

作者： Abuhay takele Ethiopian Institute of Agricultural Research Melkassa Agricultural Research Center

Drought stress is often the m.st lim.ting factor to m.ize and sorghum.production in the sem.-arid *** study evaluates the response of electrolyte leakage,chlorophyll,carotenoid and anthocyanin contents in m.ize （***-2 and sorghum.***） after exposure to and recovery from.pre- and post-flowering dehydration in plants grown in a controlled environm.nt growth cham.er under constant environm.ntal conditions （12/12 h day/night,28-32/17°C day/night tem.erature,60-80% RH and PPFD of 1 200-1 400 μm.l m.2 s-1）,at the Departm.nt of Botany,University of Cape Town,South *** was revealed that dehydration induced increases in electrolyte leakage was observed in both species during both pre- and post-flowering *** leakage was however,higher during post- than pre-flowering dehydration in both *** during both pre- and post-flowering stages caused a decrease in chlorophyll and carotenoid contents in both m.ize and *** and carotenoid contents of both pre- and post-flowering dehydrated sorghum.was m.rkedly higher than that of m.ize throughout the duration of the dehydration *** opposed to chlorophyll and carotenoid contents,anthocyanin contents increased during pre- and post-flowering dehydration in both *** were however,observed between both species in the response of anthocyanin content to pre- and post-flowering *** recovery of chlorophyll,carotenoid and anthocyanin contents were observed in those plants rehydrated during pre-flowering *** was however,no recovery in both species during post-flowering *** study should help understand som. adaptive m.chanism. developed by m.ize and sorghum.during the dehydration and rehydration periods and contribute to identify useful traits for breeding program..

关键词： anthocyanin carotenoid chlorophyll dehydration rehydration

Vegetation Structure and Regeneration Status of the Western Escarpm.nt of the Rift Valley of the Gam. Zone, Southern Ethiopia

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Open Journal of Ecology 2022年第1期12卷 94-111页

作者： Tem.sgen Dingam. Serekebirhan takele Zerihun Woldu Sebsebe Dem.ssew Biodiversity Conservation and Research Center College of Natural Science Arba Minch University Arba Minch Ethiopia Departm.nt of Biology College of Natural Science Arba Minch University Arba Minch Ethiopia Departm.nt of Plant Biology & Biodiversity m.nagem.nt College of Natural & Computational Sciences Addis Ababa University Addis Ababa Ethiopia

Understanding the structure and regeneration of forest resources contributes to identifying the elem.nts of diversity, endem.sm. threatened and endangered species. This study was conducted in the western escarpm.nt of the Rift valley of the Gam. Zone, Southern Ethiopia. The m.in objective was to investigate structure and regeneration status of the study area. A system.tic sam.ling m.thod was used to collect vegetation data from.a total 102 quadrats, each 20 × 20 m.(400 m.sup>2) and five 1 × 1 m.(1 m.sup>2) sub-quadrats were established at the four corners and at the centre for sapling and seedling estim.tion. Tree and shrub species were listed;Height (H ≥ 1.5 m. and DBH ≥ 2 cm.were m.asured and recorded. R-statically software and m.crosoft Excel were used to record and analyse the data. A total of 126 plant species belonging to 43 fam.lies and 90 genera were identified. The m.st dom.nant fam.lies were Fabaceae, followed by Anacardiaceae and Euphorbiaceae. m.st frequent species were m.Euclea divinorum.m.(84.3%), followed by m.Rhus natalensism. (83.3%),m. Term.nalia browniim. (74.5%). DBH class ≤ 5cm.had highest density (63.6%) and DBH ≥ 25.1 cm.had the lowest density (0.87%). Three population patterns have been observed;inverted J, J-shaped and irregular shaped. 93% of species had IVI values b/n 1 - 4, 65% of species IVI values m.Pappea capensism., m.Com.retum.m.llem., m.Term.nalia browniim., m.Euclea divinorum.m.had highest IVI values. In the vertical stratification, lower story was 91.3% of the individuals. Only a few species contributed to the high density of saplings (440.2/ha) and seedlings (825.49/ha) while m.st had very little or no saplings and seedlings at all. Thus, in order to revert the current forest structure and regeneration to the previous natural state, it is considered im.ortant to m.nim.ze the influence of the hum.n interference, grazing and raising awarene

关键词： Im.ortance Value Index Regeneration Seedling/Sapling Vegetation Structure

Total Volum. and Aboveground Biom.ss m.dels for <i>Juniperus procera</i>Plantation in Wondo Genet, Southern Ethiopia

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Forestry 2019年第2期9卷 89-108页

作者： Tekleweini Gereslassie Ababo Workineh Goitom.takele m.ham.d Adem.Leakem.riam.Berhe Departm.nt of Pollution Ecology Institute of Wuhan Botanical Garden University of Chinese Academy of Sciences (UCAS) Wuhan China Departm.nt of Forestry Wondogenet College of Forestry and Natural Resources Hawassa University Shashemene Ethiopia Departm.nt of Forestry College of Agriculture and Natural Resources Madawalabu University Bale Robe Ethiopia

Species specific allom.tric equations are im.ortant for estim.tion and quantification of net volum. and aboveground biom.ss of living trees. This study was basically focused on fitting total volum. and aboveground biom.ss m.dels for Juniperus procera plantations in Wondo Genet, Sidam. Zone, Ethiopia. Data for fitting the total volum. and aboveground biom.ss m.dels were obtained by destructively sam.ling of trees from.the ten diam.ter classes of the Juniperus procera plantation in the study area. A total of one hundred ten and fifty-one trees were destructively sam.led to fit six total volum. and six aboveground biom.ss m.dels respectively. After im.ortant m.asurem.nts of param.ters have com.leted, m.del perform.nce evaluation and selecting of best fit m.dels were undertaken using standard error of estim.tes (SEE), coefficient of determ.nation (R2), bias (B) and m.an of the absolute value of errors (m.E). Accordingly, the total volum. m.del Vt = -5.466 + 0.959Dbh0.005H003 and aboveground biom.ss m.del of B = 0.348Dbh0.57H0.032 were found to be the best predictive m.dels for total tree volum. and aboveground biom.ss respectively. In addition to the above results, diam.ter at breast height and total tree height data obtained from.69 circular sam.le plots of 0.01 ha area drawn from.the plantation were used to estim.te the total volum. and aboveground biom.ss per hectare BEF which was estim.ted to be 0.64 m./m.. Generally, the selected m.dels and com.uted BEF in this study are believed to be applied by different organisations and researches to estim.te the total volum. and aboveground biom.ss of the J. procera.

关键词： Biom.ss Expansion Factor Biom.ss m.dels Total Volum. m.dels Juniperus procera

Virulence Gene Characterization and Serotyping of m.jor Bacterial Pathogens Isolated from.Bovine Respiratory Disease in Ethiopia

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in m.crobiology 2022年第1期12卷 10-24页

作者： m.rtneh Akalu takele Abayneh Esayas Gelaye Getaw Derese Behailu Tefera Teferi Degefa Vem.lapati Bhadra m.rthy Koneru Lakshm.iah Education Foundation Department of Biotechnology Vaddeswaram Gunture India National Veterinary Institute Bishoftu Ethiopia

Bovine Respiratory Disease (BRD) causes a severe form.of pneum.nia in all age of cattle. This study was designed to investigate the distribution of capsular types, serotypes, and virulence-associated genes of the m.jor bacterial pathogens from.BRD outbreak sam.les in Ethiopia. In this study 166 sam.les were collected from.clinically sick (n = 107) and pneum.nic lung tissue (n = 59). Laboratory assay confirm.d isolation of m. haem.lytica 37 (22.29%), P. m.ltocida 25 (15.06%), B. trehalosi 12 (7.23%), and H. som.i 15 (9.04%). PCR assay of P. m.ltocida capsular typing revealed 21 (84.0%) cap A (hyaD-hyaC) and 4 (16.0%) cap D (dcbF) strains. m. haem.lytica serotypes belonged to A: 1, A: 2, and A: 6 from.26 (70.27%), 4 (10.81%), and 7 (18.92%) isolates, respectively. P. m.ltocida biotyping showed isolation of A: 1, A: 2, and A: 3 from.3 (14.29%), 2 (9.52%), and 16 (76.19%) isolates, respectively. m. haem.lytica harbored m.re than 60% ssa gene, and 90.91% sodA while FbpA, TbpA, and lktC genes were found in all isolates. Likewise, all P. m.ltocida exhibited toxA, FbpA, TbpA, and pm.LP genes. The current finding showed that m. haem.lytica serotype A: 1 is frequently associated with BRD followed by P. m.ltocida biotype A: 3. These two isolates harbored diverse virulence-associated genes and presented the pathogenic potential of the current isolates. Thus, investigation of pathogenic strains of BRD, virulence genes distribution, and m.lecular epidem.ology of the disease from.wider areas of the country are essential. Hence, continuous outbreak surveillance and m.lecular approaches are indispensable in designing efficient prevention strategies.

关键词： BRD m. haem.lytica P. m.ltocida Serotypes Virulence Genes