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Seasonal abundance and habitat use of bird species in and around Wondo Genet Forest,south‐central Ethiopia 下载免费PDF全文
Zerihun Girma Yosef Mamo Girma Mengesha Ashok Verma Tsyon Asfaw 《Ecology and evolution》2017,7(10):3397-3405
The habitat use and seasonal migratory pattern of birds in Ethiopia is less explored as compared to diversity studies. To this end, this study aimed at investigating the patterns of distribution related to seasonality and the effect of habitat characteristics (elevation, slope, and average vegetation height) on habitat use of birds of Wondo Genet Forest Patch. A stratified random sampling design was used to assess the avian fauna across the four dominant habitat types found in the study area: natural forest, wooded grassland, grassland, and agroforestry land. A point transect count was employed to investigate avian species richness and abundance per habitat type per season. Ancillary data, such as elevation above sea level, latitude and longitude, average vegetation height, and percent slope inclination, were recorded with a GPS and clinometers per plot. A total of 33 migratory bird species were recorded from the area, of which 20 species were northern (Palearctic) migrants while 13 were inter‐African migrants. There was a significant difference in the mean abundance of migratory bird species between dry and wet seasons (t = 2.13, p = .038, df = 44). The variation in mean abundance per plot between the dry and wet seasons in the grassland habitat was significant (t = 2.35, p = .051, df = 7). In most habitat types during both dry and wet seasons, omnivore birds were the most abundant. While slope was a good predictor for bird species abundance in the dry season, altitude and average vegetation height accounted more in the wet season. The patch of forest and its surrounding is an important bird area for migratory, endemic, and global threatened species. Hence, it is conservation priority area, and the study suggests that conservation coupled with ecotourism development is needed for its sustainability. 相似文献
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Vantieghem A Xu Y Assefa Z Piette J Vandenheede JR Merlevede W De Witte PA Agostinis P 《The Journal of biological chemistry》2002,277(40):37718-37731
The role of Bcl-2 in photodynamic therapy (PDT) is controversial, and some photosensitizers have been shown to induce Bcl-2 degradation with loss of its protective function. Hypericin is a naturally occurring photosensitizer with promising properties for the PDT of cancer. Here we show that, in HeLa cells, photoactivated hypericin does not cause Bcl-2 degradation but induces Bcl-2 phosphorylation in a dose- and time-dependent manner. Bcl-2 phosphorylation is induced by sublethal PDT doses; increasing the photodynamic stress promptly leads to apoptosis, during which Bcl-2 is neither phosphorylated nor degraded. Bcl-2 phosphorylation involves mitochondrial Bcl-2 and correlates with the kinetics of a G(2)/M cell cycle arrest, preceding apoptosis. The co-localization of hypericin with alpha-tubulin and the aberrant mitotic spindles observed following sublethal PDT doses suggest that photodamage to the microtubule network provokes the G(2)/M phase arrest. PDT-induced Bcl-2 phosphorylation is not altered by either the overexpression or inhibition of p38 mitogen-activated protein kinase (p38 MAPK) and c-Jun NH(2)-terminal protein kinase 1 (JNK1) nor by inhibiting the extracellular signal-regulated kinases (ERKs) or protein kinase C. By contrast, Bcl-2 phosphorylation is selectively suppressed by the cyclin-dependent protein kinase (CDK)-inhibitor roscovitine, completely blocked by the protein synthesis inhibitor cycloheximide and enhanced by the overexpression of CDK1, suggesting a role for this pathway. However, in an in vitro kinase assay, active CDK1/cyclin B1 complex failed to phosphorylate immunoprecipitated Bcl-2, suggesting that this protein kinase may not directly modify Bcl-2. Mutation of serine-70 to alanine in Bcl-2 abolishes PDT-induced phosphorylation and restores the caspase-3 activation to the same levels of the vector-transfected cells, indicating that Bcl-2 phosphorylation may be a signal to delay apoptosis in G(2)/M phase-arrested cells. 相似文献
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SN Rajak E Habtamu HA Weiss A Bedri M Zerihun T Gebre CE Gilbert PM Emerson MJ Burton 《PLoS neglected tropical diseases》2012,6(8):e1766
Background
Trachomatous trichiasis (TT) surgery is provided free or subsidised in most trachoma endemic settings. However, only 18–66% of TT patients attend for surgery. This study analyses barriers to attendance among TT patients in Ethiopia, the country with the highest prevalence of TT in the world.Methodology/Principal Findings
Participants with previously un-operated TT were recruited at 17 surgical outreach campaigns in Amhara Region, Ethiopia. An interview was conducted to ascertain why they had not attended for surgery previously. A trachoma eye examination was performed by an ophthalmologist. 2591 consecutive individuals were interviewed. The most frequently cited barriers to previous attendance for surgery were lack of time (45.3%), financial constraints (42.9%) and lack of an escort (35.5% in females, 19.6% in males). Women were more likely to report a fear of surgery (7.7% vs 3.2%, p<0.001) or be unaware of how to access services (4.5% vs 1.0% p<0.001); men were more frequently asymptomatic (19.6% vs 10.1%, p<0.001). Women were also less likely to have been previously offered TT surgery than men (OR = 0.70, 95%CI 0.53–0.94).Conclusions/Significance
The major barriers to accessing surgery from the patients'' perspective are the direct and indirect costs of surgery. These can to a large extent be reduced or overcome through the provision of free or low cost surgery at the community level.Trial Registration
ClinicalTrials.gov and NCT00522860 NCT00522912相似文献64.
Biology Bulletin - Eragrostis tef is a increasingly becoming popular in different parts of the world as cereal due to its wide acceptability in extreme environmental conditions where most other... 相似文献
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Jonathan D. King Tesfaye Teferi Elizabeth A. Cromwell Mulat Zerihun Jeremiah M. Ngondi Mesele Damte Frew Ayalew Zerihun Tadesse Teshome Gebre Ayelign Mulualem Alemu Karie Berhanu Melak Mitku Adugna Demelash Gessesse Abebe Worku Tekola Endashaw Fisseha Admassu Ayele Nicole E. Stoller Mary Rose A. King Aryc W. Mosher Tesfaye Gebregzabher Geremew Haileysus Peter Odermatt Jürg Utzinger Paul M. Emerson 《PLoS neglected tropical diseases》2014,8(3)
Background
To eliminate blinding trachoma, the World Health Organization emphasizes implementing the SAFE strategy, which includes annual mass drug administration (MDA) with azithromycin to the whole population of endemic districts. Prevalence surveys to assess impact at the district level are recommended after at least 3 years of intervention. The decision to stop MDA is based on a prevalence of trachomatous inflammation follicular (TF) among children aged 1–9 years below 5% at the sub-district level, as determined by an additional round of surveys limited within districts where TF prevalence is below 10%. We conducted impact surveys powered to estimate prevalence simultaneously at the sub-district and district in two zones of Amhara, Ethiopia to determine whether MDA could be stopped.Methodology
Seventy-two separate population-based, sub-district surveys were conducted in 25 districts. In each survey all residents from 10 randomly selected clusters were screened for clinical signs of trachoma. Data were weighted according to selection probabilities and adjusted for correlation due to clustering.Principal Findings
Overall, 89,735 residents were registered from 21,327 households of whom 72,452 people (80.7%) were examined. The prevalence of TF in children aged 1–9 years was below 5% in six sub-districts and two districts. Sub-district level prevalence of TF in children aged 1–9 years ranged from 0.9–76.9% and district-level from 0.9–67.0%. In only one district was the prevalence of trichiasis below 0.1%.Conclusions/Significance
The experience from these zones in Ethiopia demonstrates that impact assessments designed to give a prevalence estimate of TF at sub-district level are possible, although the scale of the work was challenging. Given the assessed district-level prevalence of TF, sub-district-level surveys would have been warranted in only five districts. Interpretation was not as simple as stopping MDA in sub-districts below 5% given programmatic challenges of exempting sub-districts from a highly regarded program and the proximity of hyper-endemic sub-districts. 相似文献67.
Testing the generality of above‐ground biomass allometry across plant functional types at the continent scale 下载免费PDF全文
Keryn I. Paul Stephen H. Roxburgh Jerome Chave Jacqueline R. England Ayalsew Zerihun Alison Specht Tom Lewis Lauren T. Bennett Thomas G. Baker Mark A. Adams Dan Huxtable Kelvin D. Montagu Daniel S. Falster Mike Feller Stan Sochacki Peter Ritson Gary Bastin John Bartle Dan Wildy Trevor Hobbs John Larmour Rob Waterworth Hugh T.L. Stewart Justin Jonson David I. Forrester Grahame Applegate Daniel Mendham Matt Bradford Anthony O'Grady Daryl Green Rob Sudmeyer Stan J. Rance John Turner Craig Barton Elizabeth H. Wenk Tim Grove Peter M. Attiwill Elizabeth Pinkard Don Butler Kim Brooksbank Beren Spencer Peter Snowdon Nick O'Brien Michael Battaglia David M Cameron Steve Hamilton Geoff McAuthur Jenny Sinclair 《Global Change Biology》2016,22(6):2106-2124
Accurate ground‐based estimation of the carbon stored in terrestrial ecosystems is critical to quantifying the global carbon budget. Allometric models provide cost‐effective methods for biomass prediction. But do such models vary with ecoregion or plant functional type? We compiled 15 054 measurements of individual tree or shrub biomass from across Australia to examine the generality of allometric models for above‐ground biomass prediction. This provided a robust case study because Australia includes ecoregions ranging from arid shrublands to tropical rainforests, and has a rich history of biomass research, particularly in planted forests. Regardless of ecoregion, for five broad categories of plant functional type (shrubs; multistemmed trees; trees of the genus Eucalyptus and closely related genera; other trees of high wood density; and other trees of low wood density), relationships between biomass and stem diameter were generic. Simple power‐law models explained 84–95% of the variation in biomass, with little improvement in model performance when other plant variables (height, bole wood density), or site characteristics (climate, age, management) were included. Predictions of stand‐based biomass from allometric models of varying levels of generalization (species‐specific, plant functional type) were validated using whole‐plot harvest data from 17 contrasting stands (range: 9–356 Mg ha?1). Losses in efficiency of prediction were <1% if generalized models were used in place of species‐specific models. Furthermore, application of generalized multispecies models did not introduce significant bias in biomass prediction in 92% of the 53 species tested. Further, overall efficiency of stand‐level biomass prediction was 99%, with a mean absolute prediction error of only 13%. Hence, for cost‐effective prediction of biomass across a wide range of stands, we recommend use of generic allometric models based on plant functional types. Development of new species‐specific models is only warranted when gains in accuracy of stand‐based predictions are relatively high (e.g. high‐value monocultures). 相似文献
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The natural forest of Masha was studied to determine the species composition and population structure of woody species in the area. A total of 130 plant species belonging 61 families were recorded, in which family Acanthaceae was represented by 11 species followed by Rubiaceae (10) and Asteraceae (9). The composition and population structure of woody species, with diameter at breast height (DBH) >2.5 cm and height >2 m, and their regeneration were assessed in 65 sample plots of 400 m2 each. The density for trees and shrubs with DBH >2.5 cm was 1681 ind.ha?1, and the basal area of the study area was 142.6 m2 ha?1. Four community types were recognized. This forest is of international and national conservation importance given its high biodiversity. Managing the remaining forest would be an appropriate option for sustainable management of biodiversity. 相似文献
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