排序方式: 共有25条查询结果,搜索用时 46 毫秒
1.
2.
K. F. Dzerzhinskii F. N. Shkil Belay Abdissa Wondie Zelalem M. V. Mina 《Journal of Ichthyology》2007,47(8):639-646
Direct observations on three forms (morph types) of spawning barbs, considered by some authors as different species, were
carried out in September–October 2005 at the Gumara River and its small tributary, the Ducalit, in the Lake Tana basin. The
spawning barbs were sampled using cast nets. Barbs of different morphotypes composed common spawning aggregations and were
caught together. It is likely that troutlike females mate extensively with intermedius males and, probably, with bigmouth
small-eye males. Experiments in artificial fertilization and rearing showed that, during the embryonic period, there was no
increase in mortality of progeny from crosses of barbs of different morphotypes, in comparison with homonomic crosses, thus
suggesting an absence of postzygotic reproductive isolation between the morphotypes. At the same time, mortality of progeny
from crossing barbs with Varicorhinus beso Rüppell, 1836 was very high during the earliest stages of development, suggesting strong, even if incomplete, reproductive
isolation ensured by postzygotic mechanisms.
Published in Voprosy Ikhtiologii, 2007, Vol. 47, No. 5, pp. 676–683.
The article was translated by the authors. 相似文献
3.
Assefa Z 《Journal of human evolution》2006,51(1):50-75
The Middle Stone Age (MSA) sediments of Porc-Epic Cave near Dire Dawa, Ethiopia, have produced a large assemblage of archaeofaunal remains dating to the later periods of the Late Pleistocene. As one of the few MSA faunal assemblages from East Africa subject to detailed analysis, it provides rare insight into the foraging behavior of the early modern humans in this region. The MSA fauna include taxa that were not historically present in the area, with the occurrence of reduncines and alcelaphines indicating widespread grasslands and proximity to a perennial source of water. The faunal analysis examined several lines of evidence, including breakage patterns, surface modification, and skeletal-element representation. By incorporating comparisons with multiple actualistic data sets, the analysis of the assemblage demonstrates that, while the influence of carnivores and other biotic agents was evident, the faunal remains were accumulated primarily by hominid activity. The skeletal-element representation at Porc-Epic includes an abundance of high utility bones, in contrast to the predominance of "head-and-foot" elements documented at other MSA and Middle Paleolithic (MP) sites. The MSA occupants of Porc-Epic effectively exploited a wide range of prey with more emphasis on small- and medium-sized mammals. 相似文献
4.
Estefanía Custodio Endalamaw Gadisa Luis Sordo Israel Cruz Javier Moreno Javier Nieto Carmen Chicharro Abraham Aseffa Zelalem Abraham Tsegaye Hailu Carmen Ca?avate 《PLoS neglected tropical diseases》2012,6(9)
Background
In northern Ethiopia the prevalence of visceral leishmaniasis is steadily rising posing an increasing public health concern. In order to develop effective control strategies on the transmission of the disease it is important to generate knowledge on the epidemiological determinants of the infection.Methodology/Principal Findings
We conducted a cross-sectional survey on children 4–15 years of age using a multi staged stratified cluster sampling on high incidence sub-districts of Amhara regional state, Ethiopia. The survey included a socio-demographic, health and dietary questionnaire, and anthropometric measurements. We performed rK39-ICT and DAT serological tests in order to detect anti-Leishmania antibodies and carried out Leishmanin Skin Test (LST) using L.major antigen. Logistic regression models were used. Of the 565 children surveyed 56 children were positive to infection (9.9%). The individual variables that showed a positive association with infection were increasing age, being male and sleeping outside [adjusted odds ratios (95% CI): 1.15 (1.03, 1.29), 2.56 (1.19, 5.48) and 2.21 (1.03, 4.71) respectively] and in relation to the household: past history of VL in the family, living in a straw roofed house and if the family owned sheep [adjusted OR (95% CI): 2.92 (1.25, 6.81), 2.71 (1.21, 6.07) and 4.16 (1.41, 12.31) respectively].Conclusions/Significance
A behavioural pattern like sleeping outside is determinant in the transmission of the infection in this area. Protective measures should be implemented against this identified risk activity. Results also suggest a geographical clustering and a household focalization of the infection. The behaviour of the vector in the area needs to be clarified in order to establish the role of domestic animals and house materials in the transmission of the infection. 相似文献5.
The Kibish faunal remains are useful for reconstructing the habitat of the earliest documented Homo sapiens and for understanding the community within which early modern humans existed. A diverse assemblage of large mammals, including many species of bovids, suids, and equids, has been recovered from the Kibish Formation. There are no extinct large mammals represented in the fossil assemblage, and the overall taxonomic composition of the fossil fauna is similar to the modern-day wildlife community living near the Omo River. The fossil faunal assemblage shows a paucity of arboreal primates, and carnivore species are rare. However, the faunal sample includes possible Cephalophus (duiker) remains and Hylochoerus meinertzhageni (giant forest hog), taxa that are extremely rare in the African fossil record, and both indicate more closed habitats. Comparative analyses of the Kibish faunal remains using the ecological-diversity approach document close associations with edaphic grassland and woodland vegetation types. These vegetation forms are similar to current habitats surrounding the Omo River. 相似文献
6.
Anthony E. Kiszewski Zelalem Teffera Melaku Wondafrash Michael Ravesi Richard J. Pollack 《Journal of vector ecology》2014,39(2):414-423
Soil pits excavated for home construction are important larval habitats for malaria vectors in certain parts of Africa. Borrow pits in diverse stages of ecological succession in a maize‐farming region of Western Ethiopia were surveyed to assess the relationships between stage of succession and the structure and composition of invertebrate and plant communities, with particular attention to Anopheles gambiae s.l. and An. coustani, the primary local malaria vectors. An array of 82 borrow pits was identified in a multi‐lobed drainage basin in the community of Woktola. Each pit was evaluated on its physical features and by faunal and floral surveys during August, 2011, at the height of the longer rainy season (kiremt). Anopheles gambiae s.l. and An. coustani were the sole immature anophelines collected, often coexisting with Culex spp. Sedges were the most common plants within these pits, and included Cyperus elegantulus, C. flavescens, C. erectus and C. assimilis. The legume Smithia abyssinica, Nile grass (Acroceras macrum), cutgrass (Leersia hexandra), clover (Trifolium spp.), and the edible herb Centella asiatica, were also common in these habitats. No plant species in particular was strongly and consistently predictive of the presence or absence of mosquito immatures, particularly with regard to An. coustani. The presence of An.gambiae s.l. immatures in borrow pit habitats was negatively correlated with the presence of backswimmers (Notonectidae) (Z = −2.34, P = 0.019). Young (freshly excavated) borrow pits more likely contained immature An. gambiae s.l. (Z =‐2.86, P=0.004). Ecological succession was apparent in older pits, and as they aged, they became less likely to serve as habitats for An. gambiae s.l. (Z=0.26, P=0.796), and more likely to support An. coustani (Z=0.728, P=0.007). As borrow pits age they become less suitable for An. gambiae s.l. breeding and more likely to harbor An. coustani. The abundance of notonectids in habitats was a negative indicator for An. gambiae s.l. abundance. Plant species are not reliable indicators for the presence or absence of malaria vectors in borrow pits. 相似文献
7.
Bivariate random‐effects meta‐analysis models for diagnostic test accuracy studies using arcsine‐based transformations 下载免费PDF全文
Zelalem F. Negeri Mateen Shaikh Joseph Beyene 《Biometrical journal. Biometrische Zeitschrift》2018,60(4):827-844
Diagnostic or screening tests are widely used in medical fields to classify patients according to their disease status. Several statistical models for meta‐analysis of diagnostic test accuracy studies have been developed to synthesize test sensitivity and specificity of a diagnostic test of interest. Because of the correlation between test sensitivity and specificity, modeling the two measures using a bivariate model is recommended. In this paper, we extend the current standard bivariate linear mixed model (LMM) by proposing two variance‐stabilizing transformations: the arcsine square root and the Freeman–Tukey double arcsine transformation. We compared the performance of the proposed methods with the standard method through simulations using several performance measures. The simulation results showed that our proposed methods performed better than the standard LMM in terms of bias, root mean square error, and coverage probability in most of the scenarios, even when data were generated assuming the standard LMM. We also illustrated the methods using two real data sets. 相似文献
8.
Zelalem Mersha Shouan Zhang Yuqing Fu Xiaodan Mo Richard N. Raid Bernhard Hau 《Journal of Phytopathology》2013,161(3):154-164
Downy mildew, caused by the oomycete pathogen Peronospora belbahrii, is a devastating foliar disease of basil in the United States and worldwide. Currently there are very few chemistries or organic choices registered to control this disease. In this study, two systemic acquired resistance (SAR) inducers, acibenzolar‐S‐methyl (ASM) and β‐aminobutyric acid (BABA), were evaluated for their in vitro effects on the pathogen, for their potential to control basil downy mildew in greenhouses, and for changes in peroxidase activity in basil plants treated with these two SAR inducers. No significant inhibition of sporangial germination was detected in water agar amended with ASM at concentrations lower than 100 mg/l or with BABA at concentrations lower than 500 mg/l. Efficacy of ASM and BABA in greenhouses varied depending on the rate, method and timing of application. The area under the disease progress curve (AUDPC) of disease severity was significantly reduced compared to the non‐treated control when ASM was sprayed (in all experiments) or drenched (in one out of two experiments) pre‐, or pre‐ + post‐inoculation at rates of 25–400 mg/l. Three weekly post‐inoculation sprays of ASM at the rate of 50 mg/l reduced AUDPC by 93.0 and 47.2% when started 3 and 7 days after inoculation (DAI), respectively. The AUDPC of disease severity was also significantly reduced when BABA was sprayed pre‐ + post‐inoculation at rates of 125–500 mg/l. According to the prediction using a log‐logistic function, 50% maximum disease protection was achieved at a concentration of 27.5 mg/l of ASM. Basil plants treated with these two SAR inducers and challenged with the pathogen showed significantly higher peroxidase activity than the non‐treated control at 8 DAI. Temporally, the highest activity of peroxidase was detected at 8 DAI, decreased at 15 DAI and waned further at 23 DAI. 相似文献
9.
Ruth Lynfield Richard Davey Dominic E. Dwyer Marcelo H. Losso Deborah Wentworth Alessandro Cozzi-Lepri Kathy Herman-Lamin Grazyna Cholewinska Daniel David Stefan Kuetter Zelalem Ternesgen Timothy M. Uyeki H. Clifford Lane Jens Lundgren James D. Neaton for the INSIGHT Influenza Study Group 《PloS one》2014,9(7)
Background
Data from prospectively planned cohort studies on risk of major clinical outcomes and prognostic factors for patients with influenza A(H1N1)pdm09 virus are limited. In 2009, in order to assess outcomes and evaluate risk factors for progression of illness, two cohort studies were initiated: FLU 002 in outpatients and FLU 003 in hospitalized patients.Methods and Findings
Between October 2009 and December 2012, adults with influenza-like illness (ILI) were enrolled; outpatients were followed for 14 days and inpatients for 60 days. Disease progression was defined as hospitalization and/or death for outpatients, and hospitalization for >28 days, transfer to intensive care unit (ICU) if enrolled from general ward, and/or death for inpatients. Infection was confirmed by RT-PCR. 590 FLU 002 and 392 FLU 003 patients with influenza A (H1N1)pdm09 were enrolled from 81 sites in 17 countries at 2 days (IQR 1–3) and 6 days (IQR 4–10) following ILI onset, respectively. Disease progression was experienced by 29 (1 death) outpatients (5.1%; 95% CI: 3.4–7.2%) and 80 inpatients [death (32), hospitalization >28 days (43) or ICU transfer (20)] (21.6%; 95% CI: 17.5–26.2%). Disease progression (death) for hospitalized patients was 53.1% (26.6%) and 12.8% (3.8%), respectively, for those enrolled in the ICU and general ward. In pooled analyses for both studies, predictors of disease progression were age, longer duration of symptoms at enrollment and immunosuppression. Patients hospitalized during the pandemic period had a poorer prognosis than in subsequent seasons.Conclusions
Patients with influenza A(H1N1)pdm09, particularly when requiring hospital admission, are at high risk for disease progression, especially if they are older, immunodeficient, or admitted late in infection. These data reinforce the need for international trials of novel treatment strategies for influenza infection and serve as a reminder of the need to monitor the severity of seasonal and pandemic influenza epidemics globally.Trial Registration
ClinicalTrials.gov Identifiers: FLU 002- , FLU 003- NCT01056354. NCT01056185相似文献10.
Yassin MA Petrucci R Garie KT Harper G Arbide I Aschalew M Merid Y Kebede Z Bawazir AA Abuamer NM Cuevas LE 《PloS one》2011,6(9):e23733