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Tadesse Dejenie Tsehaye Asmelash Luc De Meester Afework Mulugeta Abreha Gebrekidan Sarah Risch Annemie Pals Katleen Van der Gucht Wim Vyverman Jan Nyssen Jozef Deckers Steven Declerck 《Hydrobiologia》2008,610(1):193-209
The semi-arid highlands of Northern Ethiopia (Tigray) have numerous small reservoirs that have been created by microdams in
an attempt to provide water supply for irrigation and livestock drinking. Although the reservoirs have substantial added value
to residents, their use as water resource is jeopardized by eutrophication and a high occurrence of blooms of toxic cyanobacteria.
So far, there is no systematic information available on the limnological and aquatic ecological characteristics of these dams.
We carried out a standardized survey of 32 reservoirs and assessed a wide set of morphometric, abiotic and biotic variables.
The sampling was performed during two seasons, September–October 2004 (end of the wet season/start of the dry season) and
April–May 2005 (towards the end of the dry season). Using multivariate analysis, we revealed dominating patterns of variable
associations and compared the variability in these patterns among seasons. According to standardized PCA and RDA analyses,
the most important axis of variation was mainly represented by a gradient in nutrients and altitude that was also positively
associated with phytoplankton biomass, suspended matter and oxygen concentration, and negatively with water transparency.
For most variables, correlations between the wet and dry season were weak, which suggests that individual reservoirs behaved
rather differently in their response to seasonal changes. Nevertheless, a Mantel correlation (r = 0.32; P = 0.035) showed a weak but significant overall concordance in the variable association patterns among seasons. A number of
reservoirs became very shallow or fell dry in the dry season, a process that was associated with an increase in suspended
matter and conductivity and a decrease in transparency. These reservoirs contained lower amounts of fish and tended to be
less eutrophic than the deeper, permanent systems, as they had lower levels of phosphorus and chlorophyll-a. With multiple regression analysis, we constructed most parsimonious models in an attempt to explain the variation in key
biotic variables: phytoplankton and cyanobacteria biomass, cladoceran biomass, fish biomass and the abundance of submerged
vegetation. Phytoplankton and fish biomass tended to be positively related with the concentration of total phosphorus, whereas
cladoceran biomass was not associated with nutrient concentrations. The positive association of fish and phytoplankton with
nutrient concentrations suggests a bottom-up control, whereas the absence of an association between zooplankton and nutrient
concentrations may be indicative for top-down control. The biomass of cyanobacteria was negatively related to the biomass
of cladocerans (Daphnia), which likely reflects a top-down effect. Most reservoirs were turbid. The occurrence and abundance of macrophytes tended
to be positively related to water transparency and was negatively associated to TP and the amount of livestock frequenting
the reservoirs. However, macrophytes were not limited to clear-water reservoirs.
Handling editor: L. M. Bini 相似文献
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The use of ribotyping and antibiotic resistance patterns for identification of host sources of Escherichia coli strains 总被引:1,自引:0,他引:1
AIMS: To compare antibiotic resistance and ribotyping patterns ability to identify triplicate isolates sent from a group of 40 Escherichia coli taken from seven host sources. METHODS AND RESULTS: Of the 120 isolates, 22 isolates were resistant to ampicillin, streptomycin, tetracycline and trimethoprim and 98 isolates were susceptible. Antibiotic patterns identified 33 of the triplicates and three of the six groups had isolates from multiple hosts. Ribotyping divided the isolates into 27 ribotype groups with all triplicates grouped into the same ribotype group with one host per group. CONCLUSIONS: Antibiotic susceptibility pattern placed 98 of the isolates in a single group with 50% of the antibiotic susceptibility pattern groups containing multiple host species. Ribotyping groups were host specific with each host having one to seven ribotype groups. SIGNIFICANCE AND IMPACT OF THE STUDY: Antibiotic susceptibility pattern groups have been used for environmental source identification and faecal pollution tracking, however these groups do not always distinguish between host species. Stability of the markers is a potential concern and this system can only be used if antibiotic resistance levels are high in the isolates studied. All isolates have a ribotype group which was stable and like other molecular methods has advantages over antibiotic susceptibility pattern groups which uses a phenotypic method. 相似文献
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Christopher C. Smitson Admasu Tenna Mulugeta Tsegaye Abere S. Alemu Daniel Fekade Abraham Aseffa Henry M. Blumberg Russell R. Kempker 《PloS one》2014,9(1)
Introduction
There are limited data on clinical outcomes of ART-experienced patients with cryptococcal antigenemia. We assessed clinical outcomes of a predominantly asymptomatic, ART-experienced cohort of HIV+ patients previously found to have a high (8.4%) prevalence of cryptococcal antigenemia.Methods
The study took place at All Africa Leprosy, Tuberculosis and Rehabilitative Training Centre and Black Lion Hospital HIV Clinics in Addis Ababa, Ethiopia. A retrospective study design was used to perform 12-month follow-up of 367 mostly asymptomatic HIV-infected patients (CD4<200 cells/µl) with high levels of antiretroviral therapy use (74%) who were previously screened for cryptococcal antigenemia. Medical chart abstraction was performed approximately one year after initial screening to obtain data on clinic visit history, ART use, CD4 count, opportunistic infections, and patient outcome. We evaluated the association of cryptococcal antigenemia and a composite poor outcome of death and loss to follow-up using logistic regression.Results
Overall, 323 (88%) patients were alive, 8 (2%) dead, and 36 (10%) lost to follow-up. Among the 31 patients with a positive cryptococcal antigen test (titers ≥1∶8) at baseline, 28 were alive (all titers ≤1∶512), 1 dead and 2 lost to follow-up (titers ≥1∶1024). In multivariate analysis, cryptococcal antigenemia was not predictive of a poor outcome (aOR = 1.3, 95% CI 0.3–4.8). A baseline CD4 count <100 cells/µl was associated with an increased risk of a poor outcome (aOR 3.0, 95% CI 1.4–6.7) while an increasing CD4 count (aOR 0.1, 95% CI 0.1–0.3) and receiving antiretroviral therapy at last follow-up visit (aOR 0.1, 95% CI 0.02–0.2) were associated with a reduced risk of a poor outcome.Conclusions
Unlike prior ART-naïve cohorts, we found that among persons receiving ART and with CD4 counts <200 cells/µl, asymptomatic cryptococcal antigenemia was not predictive of a poor outcome. 相似文献76.
Identification of LBM180, a lamellar body limiting membrane protein of alveolar type II cells, as the ABC transporter protein ABCA3 总被引:8,自引:0,他引:8
Mulugeta S Gray JM Notarfrancesco KL Gonzales LW Koval M Feinstein SI Ballard PL Fisher AB Shuman H 《The Journal of biological chemistry》2002,277(25):22147-22155
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Samuel Woldemariam Sahile Zewdu Teshome Mulugeta Kibret 《Archives Of Phytopathology And Plant Protection》2013,46(9-10):461-484
AbstractIntegrated management of faba bean chocolate spot (Botrytis fabae Sard.) was studied using moderately tolerant variety, “Hachalu” and the local cultivar at Chilga district during 2016 main cropping season. The objective was to evaluate effect of host resistance, intercropping and fungicide applications on epidemics of faba bean chocolate spot, yield and yield components of faba bean, and sole and intercrop systems productivity. The experiment was randomised complete block design in a factorial combination of two faba bean cultivars, two cropping systems (Hachalu- and local-barley intercropping in 2:1 ratio) and four levels of fungicide (Chlorothalonil) spray and integration in three replications of faba bean and barley, respectively. Cultivars and spray intervals significantly (p?<?.01) affected the seed yield while cultivars alone had significant variation (p?<?.01) on 100-seed weight as a main effect. Therefore, 21-days fungicide spray intervals integrated with Hachalu sole and Hachalu-barley intercropping may be considered for chocolate spot management. 相似文献
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Jonathan D. King Tekola Endeshaw Elisabeth Escher Genetu Alemtaye Sileabatt Melaku Woyneshet Gelaye Abebe Worku Mitku Adugna Berhanu Melak Tesfaye Teferi Mulat Zerihun Demelash Gesese Zerihun Tadesse Aryc W. Mosher Peter Odermatt Jürg Utzinger Hanspeter Marti Jeremiah Ngondi Donald R. Hopkins Paul M. Emerson 《PLoS neglected tropical diseases》2013,7(6)
Background
The SAFE strategy aims to reduce transmission of Chlamydia trachomatis through antibiotics, improved hygiene, and sanitation. We integrated assessment of intestinal parasites into large-scale trachoma impact surveys to determine whether documented environmental improvements promoted by a trachoma program had collateral impact on intestinal parasites.Methodology
We surveyed 99 communities for both trachoma and intestinal parasites (soil-transmitted helminths, Schistosoma mansoni, and intestinal protozoa) in South Gondar, Ethiopia. One child aged 2–15 years per household was randomly selected to provide a stool sample of which about 1 g was fixed in sodium acetate-acetic acid-formalin, concentrated with ether, and examined under a microscope by experienced laboratory technicians.Principal Findings
A total of 2,338 stool specimens were provided, processed, and linked to survey data from 2,657 randomly selected children (88% response). The zonal-level prevalence of Ascaris lumbricoides, hookworm, and Trichuris trichiura was 9.9% (95% confidence interval (CI) 7.2–12.7%), 9.7% (5.9–13.4%), and 2.6% (1.6–3.7%), respectively. The prevalence of S. mansoni was 2.9% (95% CI 0.2–5.5%) but infection was highly focal (range by community from 0–52.4%). The prevalence of any of these helminth infections was 24.2% (95% CI 17.6–30.9%) compared to 48.5% as found in a previous study in 1995 using the Kato-Katz technique. The pathogenic intestinal protozoa Giardia intestinalis and Entamoeba histolytica/E. dispar were found in 23.0% (95% CI 20.3–25.6%) and 11.1% (95% CI 8.9–13.2%) of the surveyed children, respectively. We found statistically significant increases in household latrine ownership, use of an improved water source, access to water, and face washing behavior over the past 7 years.Conclusions
Improvements in hygiene and sanitation promoted both by the SAFE strategy for trachoma and health extension program combined with preventive chemotherapy during enhanced outreach services are plausible explanations for the changing patterns of intestinal parasite prevalence. The extent of intestinal protozoa infections suggests poor water quality or unsanitary water collection and storage practices and warrants targeted intervention. 相似文献79.
Wondi Mersie Lidya Alemayehu Lorraine Strathie Andrew McConnachie Shitaye Terefe Mulugeta Negeri 《Biocontrol Science and Technology》2019,29(3):239-251
The invasive weed, parthenium (Parthenium hysterophorus L.) (Asteraceae: tribe Heliantheae), damages agriculture, adversely impacts biodiversity and is hazardous to human and animal health in Ethiopia. The host range of two natural enemies, a leaf-feeding beetle, Zygogramma bicolorata (Coleoptera: Chrysomelidae) and a stem-boring weevil, Listronotus setosipennis (Coleoptera: Curculionidae) was evaluated for biological control of the weed in Ethiopia. The specificity of Z. bicolorata and L. setosipennis was assessed against 29 and 31 non-target plant species, respectively. The host range of Z. bicolorata and L. setosipennis was first assessed using no-choice tests to examine their oviposition and feeding response on non-target plants. Although oviposition by Z. bicolorata occurred on six non-target species in four Asteraceae species in no-choice tests, it was significantly lower than on parthenium and no larvae developed. Zygogramma bicolorata nibbled the leaves of one of the five niger seed (Guizotia abyssinica L. – an oil seed crop closely related to parthenium) cultivars tested, but feeding and oviposition were significantly less than on parthenium. Furthermore, choice tests indicated that Z. bicolorata did not oviposit nor feed on G. abyssinica when parthenium was present. In no-choice tests, L. setosipennis did not oviposit on any of the non-target species assessed. Mean oviposition on parthenium was 39.0?±?3.4 eggs per plant whereas no eggs were laid on any of the 31 species tested. Based on these and other host range tests, permission was obtained to field release Z. bicolorata and L. setosipennis in Ethiopia. 相似文献
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