The aim of the current study was to investigate the effects of a lactic acid bacteria inoculant（Lactobacillus plantarum, LP）, fibrolytic enzyme（EN）, combination of LP and EN（LP＋EN） on fermentation quality, nutr...The aim of the current study was to investigate the effects of a lactic acid bacteria inoculant（Lactobacillus plantarum, LP）, fibrolytic enzyme（EN）, combination of LP and EN（LP＋EN） on fermentation quality, nutritive characteristics and in vitro digestibility of total mixed ration（TMR） silages containing 0, 7.5 and 15.0%（on dry matter basis） of rape（Brassica campestris L.） straw（RS）（denoted as CTMR, LTMR and MTMR, respectively）. After ensiling for 60 days, TMR silages without additives were well preserved, but MTMR had higher p H than CTMR and LTMR. There were no differences in other parameters of fermentation quality, microbial composition, nutrition and in vitro digestibility between CTMR and LTMR except for yeast and mold number and crude protein（CP） content. CTMR and LTMR silage had higher CP content, in vitro neutral detergent fiber digestibility（IVNDFD） and in vitro acid detergent fiber digestibility（IVADFD）, lower acid detergent fiber（ADF） content than MTMR silage. LP and EN decreased p H and increased dry matter（DM） recovery of TMR silages. LP＋EN improved the fermentation quality, nutritive characteristics and in vitro digestibility of TMR silages, showed by lower p H, ADF content, higher lactic acid content, in vitro dry matter digestibility（IVDMD） and IVNDFD. Therefore, It was suggested that TMR silage contained 7.5% RS on a DM basis and treated with LP＋EN can be as a useful feed for ruminant.展开更多
The Lake Tana area is located within a complex volcano-tectonic basin on the northwestern Ethiopian plateau.The basin is underlain by a thick succession of Oligocene transitional basalts and sub-alkaline rhyolites ove...The Lake Tana area is located within a complex volcano-tectonic basin on the northwestern Ethiopian plateau.The basin is underlain by a thick succession of Oligocene transitional basalts and sub-alkaline rhyolites overlain in places,particularly south of the lake,by Quaternary alkaline to mildly transitional basalts,and dotted with Oligo-Miocene trachyte domes and plugs.This paper presents the results of integrated field,petrographic,and major and trace element geochemical studies of the Lake Tana area volcanic rocks,with particular emphasis on the Oligocene basalts and rhyolites.The studies reveal a clear petrogenetic link between the Oligocene basalts and rhyolites.The Oligocene basalts are:(1)plagioclase,olivine,and/or pyroxene phyric;(2)show an overall decreasing trend in MgO,Fe_(2)O_(3),and CaO with silica;(3)have relatively low Mg#,Ni and Cr contents and high Nb/La and Nb/Yb ratios;and(4)show LREE enriched and generally flat HREE patterns.All these imply the origin of the Oligocene basalts by shallow-level fractional crystallization of an enriched magma sourced at the asthenospheric mantle.The Oligocene rhyolites:(1)are enriched in incompatible while depleted in compatible trace elements,P and Ti;(2)show a strong negative Eu anomaly;(3)contain appreciable amounts of plagioclase,apatite,and Fe-Ti oxides;and(4)show clear geochemical similarity with well-constrained rhyolites from the Large Igneous Province(LIP)of the northwestern Ethiopian plateau.Low-pressure fractional crystallization of mantle-derived basaltic magma in crustal magma chambers explains the origin of these rhyolites.Our study further shows that the Oligocene basalts and rhyolites are co-genetic and the felsic rocks of the Lake Tana area are related differentiates of the flood basalt volcanism in the northwestern Ethiopian plateau.展开更多
BACKGROUND: Premature rupture of membrane(PROM) is linked to significant maternal prenatal mortalities and morbidity. In Ethiopia, where maternal mortality is still high, the maternal and fetal outcomes in PROM is ver...BACKGROUND: Premature rupture of membrane(PROM) is linked to significant maternal prenatal mortalities and morbidity. In Ethiopia, where maternal mortality is still high, the maternal and fetal outcomes in PROM is very important to decrease maternal and child mortality and for better management and prevention of complications. Thus, this study aimed to detect the maternal and fetal outcomes and associated factors in term PROM at Mizan-Aman General Hospital, south-west Ethiopia.METHODS: A retrospective cross sectional study was conducted using data available at MizanAman General Hospital during a period of 3 years(January 2011 to December 2013). We examined records of 4 525 women who gave birth in the hospital; out of these women, 185 were diagnosed with term PROM and all of them were included in the study. The data of these women were collected using a checklist based on registration books. The data were analyzed using SPSS version 20.0 statistical package. The association between independent and dependent variables was assessed by bivariate and multiple logistic regression analyses. 95%CI and P value less than 0.05 were considered statistically signifi cant.RESULTS: Of the 4 525 women who gave birth in the hospital, 202 were complicated by term PROM. About 22.2% of the women showed unfavorable maternal outcomes. The most common cause of maternal morbidity and mortality was puerperal sepsis. About 33.5% of neonates experienced unfavorable outcomes. The duration of PROM >12 hours(AOR=5.6, 95%CI 1.3–24.1) latency >24 hours(AOR=2.8, 95%CI 1.7–11.8), residing in rural areas(AOR=4.2, 95%CI 3.96–29.4) and birth weight less than 2 500 g were associated with unfavorable outcomes.CONCLUSION: Women residing in rural areas, long latency, and neonates with birth weight less 2 500 g may have unfavorable outcomes. Therefore, optimum obstetric and medical care is essential for the reduction of the devastating complications related to disorders.展开更多
The Safe Schools Declaration of 2015 is an inter-governmental political agreement signed by several countries designed to protect the schooling of the school-aged population during armed conflicts.Yet,in countries whe...The Safe Schools Declaration of 2015 is an inter-governmental political agreement signed by several countries designed to protect the schooling of the school-aged population during armed conflicts.Yet,in countries where civil war erupted,schools were demolished.Several school-aged children were either forcibly recruited by governments or coerced by rebel groups to serve in armed fights.As a result,several children were deprived of their education and have remained suffering from deep psychological scars.The central question of the study is:What kind of sustainability-driven school buildings can be initiated in countries that are now enduring peace so that the learning environments are more comfortable and improve the well-being of the war-impacted children and school employees?After reviewing the literature,a strategic conceptual framework that incorporated the synergistic relationship between economic,social,and environmental aspects of sustainability was initiated to map out sustainable school buildings.In short,the conceptual framework proposed to construct school buildings in some of the war-affected developing countries includes assembling cost-efficiency and eco-effectiveness inputs,using renewable energy sources powered by natural sunlight,collecting rainwater in mud cisterns,reducing emissions of carbon oxides,and empowering the local community to be the main actors to design sustainable buildings during the preconstruction,construction,and post-construction stages to serve as learning spaces for the war-affected occupants and their neighborhoods.展开更多
In this report,a series of novel piperidine-substituted thiophene[3,2-d]pyrimidine derivatives were designed to explore the hydrophobic channel of the non-nucleoside reverse transcriptase inhibitors binding pocket(NNI...In this report,a series of novel piperidine-substituted thiophene[3,2-d]pyrimidine derivatives were designed to explore the hydrophobic channel of the non-nucleoside reverse transcriptase inhibitors binding pocket(NNIBP)by incorporating an aromatic moiety to the left wing of the lead K-5 a2.The newly synthesized compounds were evaluated for anti-HIV potency in MT-4 cells and inhibitory activity to HIV-1 reverse transcriptase(RT).Most of the synthesized compounds exhibited broad-spectrum activity toward wild-type and a wide range of HIV-1 strains carrying single non-nucleoside reverse transcriptase inhibitors(NNRTI)-resistant mutations.Especially,compound 26 exhibited the most potent activity against wild-type and a panel of single mutations(L1001,K103 N,Y181 C,Y188 L and E138 K)with an EC50 ranging from 6.02 to 23.9 nmol/L,which were comparable to those of etravirine(ETR).Moreover,the RT inhibition activity,preliminary structure-activity relationship and molecular docking were also investigated.Furthermore,26 exhibited favorable pharmacokinetics(PK)profiles and with a bioavailability of 33.8%.Taken together,the results could provide valuable insights for further optimization and compound 26 holds great promise as a potential drug candidate for the treatment of HIV-1 infection.展开更多
BACKGROUND: Rapid sequence induction and intubation(RSII) is an emergency airway management technique for patients with a risk of pulmonary aspiration. It involves preoxygenation, administration of predetermined doses...BACKGROUND: Rapid sequence induction and intubation(RSII) is an emergency airway management technique for patients with a risk of pulmonary aspiration. It involves preoxygenation, administration of predetermined doses of induction and paralytic drugs, avoidance of mask ventilation, and laryngoscopy followed by tracheal intubation and keeping cricoid pressure applied till endotracheal tube cuff be inflated. Oxygen desaturation has been seen during RSII. We assessed the incidence of oxygen desaturation during RSII.METHODS: An institution-based observational study was conducted from March 3 to May 4, 2014 in our hospital. All patients who were operated upon under general anesthesia with RSII during the study period were included. A checklist was prepared for data collection.RESULTS: A total of 153 patients were included in this study with a response rate of 91.6%. Appropriate drugs for RSII, equipments for RSII, equipments for diffi cult intubation, suction machine with a catheter, a monitor and an oxygen backup such as ambu bag were not prepared for 41(26.8%), 50(32.7%), 51(33.3%), 38(24.8%) and 25(16.3%) patients respectively. Cricoid pressure was not applied at all for 17(11.1%) patients and 53(34.6%) patients were ventilated after induction of anesthesia but before intubation and endotracheal cuff inflation. A total of 55(35.9%) patients desaturated during RSII(SPO2<95%). The minimum, maximum and mean oxygen desaturations were 26%, 94% and 70.9% respectively. The oxygen desaturation was in the range of <50%, 50%–64%, 65%–74%, 75%–84%, 85%–89 % and 90%–94% for 6(3.9%), 7(4.6%), 5(3.3%), 10(6.5%), 13(8.5%) and 14(9.2%) patients respectively.CONCLUSION: The incidence of oxygen desaturation during RSII was high in our hospital. Preoperative patient optimization and training about the techniques of RSII should be emphasized.展开更多
Scalable production methods and low-cost materials with low embodied energy are key to success for organic solar cells.PEDOT(PSS)electrodes meet these criteria and allow for low-cost and all solution-processed solar c...Scalable production methods and low-cost materials with low embodied energy are key to success for organic solar cells.PEDOT(PSS)electrodes meet these criteria and allow for low-cost and all solution-processed solar cells.However,such devices are prone to shunting.In this work we introduce a roll-to-roll lamination method to construct semitransparent solar cells with a PEDOT(PSS)anode and an polyethyleneimine(PEI)modified PEDOT(PSS)cathode.We use the polymer:PCBM active layer coated on the electrodes as the lamination adhesive.Our lamination method efficiently eliminates any shunting.Extended exposure to ambient degrades the laminated devices,which manifests in a significantly reduced photocurrent extraction when the device is illuminated through the anode,despite the fact that the PEDOT(PSS)electrodes are optically equivalent.We show that degradation-induced electron traps lead to increased trap-assisted recombination at the anode side of the device.By limiting the exposure time to ambient during production,degradation is significantly reduced.We show that lamination using the active layer as the adhesive can result in device performance equal to that of conventional sequential coating.展开更多
This study examines the effects of industrial parks on export earnings,employment creation,and FDI attraction in Ethiopia.Despite varying degrees of successes and failures,several countries have utilized industrial pa...This study examines the effects of industrial parks on export earnings,employment creation,and FDI attraction in Ethiopia.Despite varying degrees of successes and failures,several countries have utilized industrial park and other forms of special economic zones as a policy instrument for fostering economic transformation.China is at the forefront of using special economic zones as a policy tool for economic transformation.Ethiopia is one of the African countries that has adopted industrial park development as a policy tool to enhance its economic transformation.However,the issue is not well researched and this study aims to contribute to fill the research gap.The analysis of the hypotheses test reveals that industrial parks in Ethiopia have statistically significant effects on export earnings,employment creation,and FDI attraction with significant levels of p≤0.001.Low labor productivity,domestic raw material supply constraints,weak forward and backward linkage,transport cost and logistic constraints,and government institutions’capacity constraints are identified as the major constraints that affect the effectiveness of industrial parks and manufacturing firms.On the other hand,the availability of a trainable labor force,raw material potential,preferential policies and incentives,the economic growth of the country,and the labor wage rise in China and other emerging countries are identified as the main five potentials and opportunities for sustained and dynamic industrial parks development.Based on the findings,three policy implications are suggested.First,formulating and implementing manufacturing labor force development and utilization policies and strategies are vital.Second,the forward-backward linkage along the value chain needs to be enhanced through proper policies.Finally,institutional capacity building through learning by doing and public-private partnership has to be strengthened.展开更多
A review of the literature indicates that,currently,Ethiopia is now beyond the bounds of fragility.The purpose of the study was to investigate whether Ethiopia was experiencing fragility.After a review of the literatu...A review of the literature indicates that,currently,Ethiopia is now beyond the bounds of fragility.The purpose of the study was to investigate whether Ethiopia was experiencing fragility.After a review of the literature on fragility,a theoretical framework lens on fragility was developed to empirically test Ethiopia’s current condition.A longitudinal analysis indicates that before 2018,Ethiopia was regarded as the central economic engine of sub-Saharan Africa.However,as the current regime reversed Ethiopia’s developmental state model and moved to follow a neo-liberal model,Ethiopia’s economy has gradually diminished.More specifically,during the current regime,Ethiopia has experienced a decline in its Gross Domestic Product,faced rampant unemployment,and encountered an increase in inflation.Its foreign exchange currency reserves have declined below the three-month threshold of hard currency required for a country to import goods and services,and its external debt has extended beyond the country’s GDP.By encouraging armed conflict and widespread insurgencies,the current regime has caused social tension and deep humanitarian crises in Ethiopia-resulting in devastation of health and school facilities and causing more than five million Ethiopians to be displaced.Finally,failing to provide leadership to his people,the current regime in Ethiopia has willingly allowed the incursion of Ethiopia’s sovereignty by foreign forces.The conclusion of the study is that,when observed through the lens of fragility using a longitudinal framework,currently,Ethiopia has traversed beyond fragility and seems to be heading toward balkanization.展开更多
Geospatial information acquired with Unmanned Aerial Vehicles(UAV)provides valuable decision-making support in many different domains,and technological advances coincide with a demand for ever more sophisticated data ...Geospatial information acquired with Unmanned Aerial Vehicles(UAV)provides valuable decision-making support in many different domains,and technological advances coincide with a demand for ever more sophisticated data products.One consequence is a research and development focus on more accurately referenced images and derivatives,which has long been a weakness especially of low to medium cost UAV systems equipped with relatively inexpensive inertial measurement unit(IMU)and Global Navigation Satellite System(GNSS)receivers.This research evaluates the positional accuracy of the real-time kinematics(RTK)GNSS on the DJI Matrice 600 Pro,one of the first available and widely used UAVs with potentially surveying-grade performance.Although a very high positional accuracy of the drone itself of 2 to 3 cm is claimed by DJI,the actual accuracy of the drone RTK for positioning the images and for using it for mapping purposes without additional ground control is not known.To begin with,the actual GNSS RTK position of reference center(the physical point on the antenna)on the drone is not indicated,and uncertainty regarding this also exists among the professional user community.In this study the reference center was determined through a set of experiments using the dual frequency static Leica GNSS with RTK capability.The RTK positioning data from the drone were then used for direct georeferencing,and its results were evaluated.Test flights were carried out over a 70 x 70 m area with an altitude of 40 m above the ground,with a ground sampling distance of 1.3 cm.Evaluated against ground control points,the planimetric accuracy of direct georeferencing for the photogrammetric product ranged between 30 and 60 cm.Analysis of direct georeferencing results showed a time delay of up to 0.28 seconds between the drone GNSS RTK and camera image acquisition affecting direct georeferencing results.展开更多
Tef is grown as<span> an</span><span> important domestic cereal in Ethiopia. Currently</span><span>,</span><span> global attention is given for it particularly as a </span&...Tef is grown as<span> an</span><span> important domestic cereal in Ethiopia. Currently</span><span>,</span><span> global attention is given for it particularly as a </span><span>“</span><span>health food</span><span>”</span><span> due to the absence of gluten and gluten like proteins in its grains. Regardless of its wider adaptation, productivity of tef is low in the country with the national average grain yield of 1.379 tons·ha</span><sup><span style="vertical-align:super;">-1</span></sup><span>. This is mainly because of low soil fertility and severe organic matter depletion intensified by low rate of chemical fertilizer application. This study was conducted to evaluate effects of balanced fertilizers on the yield, yield components of tef and to determine economic feasibility for tef production in Wolaita. The experiment was laid out in a randomized complete block design (RCBD) with sixteen treatments replicated three times. The treatments consist of factorial combinations of four rates of K (Potassium) (0, 25, 50, and 100 kg/ha) and four rates of NPSB (Nitrogen, Phosphorus, Sulfur and Boron) (0, 50, 100, 200 kg/ha) fertilizers. Fertilizer types such as urea (46-0-0), NPSB (18.9-37.7-6.95-0.1) and K (0-0-60) were used as a source of nutrients. The soil analysis result indicated that, most of the nutrients are below optimum level to support the potential crop production. This may be related with reduced farm management practices and continuous cropping with little or no fertilizers input. In this study</span><span>,</span><span> it was found that, the combined application of NPSB and K fertilizers had </span><span>a </span><span>significant effect on growth, yield and yield components of tef. Among the treatments studied, NPSB (100</span><span> </span><span>Kg/ha) and K (50</span><span> </span><span>Kg/ha) gave greater grain yield. Furthermore, this treatment enhanced growth and yield related parameters compared to the control treatment. Thus, it is conceivable to recommend each to attain greater grain yiel展开更多
AIM：To assess the pattern of ocular manifestation and associated factors among human immunodeficiency virus（HIV）/acquired immunodeficiency syndrome（AIDS） patients on highly active antiretroviral therapy（HAART） ...AIM：To assess the pattern of ocular manifestation and associated factors among human immunodeficiency virus（HIV）/acquired immunodeficiency syndrome（AIDS） patients on highly active antiretroviral therapy（HAART） at Hawassa University Referral Hospital, Southern Ethiopia. METHODS：A cross sectional study was conducted from January 2014 to April 2015. After obtaining informed written consent, 240 adult HIV/AIDS patients on HAART were randomly selected regardless of their ophthalmic symptoms, WHO status or CD4 count. Data were collected using structured questionnaires and ophthalmologic clinical examination. Data were entered and analyzed using SPSS version 20.0 software. RESULTS：The mean duration of HAART was 62.5mo. The prevalence of HIV related ocular manifestation was 14.2%. Seborrheic blepharitis（5%） was the most common ocular manifestation, followed by squamoid conjunctival growth（3.8%）. The rate of ocular manifestation was significantly higher among study participants who had CD4＋ count 〈200 cells/μL（AOR=3.83; 95%CI：1.315-11.153）, low duration of HAART（AOR=3.0; 95%CI：1.305-6.891） and who had primary school education [odds ratio（OR） =2.8; 95%CI：1.105-7.099]. Prevalence of visual impairment and blindness was 10.9% and 5.8%, respectively.CONCLUSION：HAART may be the reason for the decline in the prevalence of ocular manifestation in HIV/AIDS patients in the study area. Ophthalmologic screening of HIV/AIDS patients, especially those with CD4 counts of 〈200/μL cells and in the first five years of HAART followup is recommended to reduce visual impairment and/or blindness.展开更多
The runoff coefficient (RC) is the ratio between the runoff and rainfall amounts and is scale dependent, which is due in part to the heterogeneity of watershed characteristics. This study quantified the spatial scale ...The runoff coefficient (RC) is the ratio between the runoff and rainfall amounts and is scale dependent, which is due in part to the heterogeneity of watershed characteristics. This study quantified the spatial scale effects on runoff using long-term rainfall-runoff data on runoff plots and small watersheds. Effect of spatial scale on RC was studied for 12 runoff plots (2m by 15m) and three small watersheds (113-477 ha) in the highlands of Ethiopia using a total of 4397 and 13,92515-day cumulative pairs of rainfall and runoff data at watershed and runoff plot scales, respectively. The observed average RC of runoff plots was extrapolated based on the extent of representation of a particular watershed in terms of slope, land use, cover and soil type. The weighted RC of plots was then compared with the observed RC of the watershed to determine a scale factor for extrapolation. A decrease in RC from plot to the watershed was observed in Anjeni and Andit Tid watersheds, while an increase in RC in Maybar watershed illustrates the role of specific watershed conditions in determining the scale effect. This, in turn, suggests that the variation in scale factor is not well explained by the difference in the area alone. The scale effect of runoff generation was better explained by extrapolating the RC based on the representation of different watershed characteristics. Thus, extrapolation exercises in runoff modeling and scaling efforts of soil and water conservation practices should consider the scale effect cautiously.展开更多
Identifying land management practices(LMPs)that enhance on-site sediment management and crop productivity is crucial for the prevention,reduction,and restoration of land degradation and contributing to achieving land ...Identifying land management practices(LMPs)that enhance on-site sediment management and crop productivity is crucial for the prevention,reduction,and restoration of land degradation and contributing to achieving land degradation neutrality(LDN).We reviewed studies in Ethiopia to assess the effects of LMPs on soil loss(84 studies)and crop productivity(34 studies)relative to control practice.Yield variability on conserved lands was assessed using 12,796 fixed plot data.Effects of LMP on soil loss were 0.5-55 t ha^(−1)y^(−1)compared to control practices yielding 50 to 140 t ha^(−1)y^(−1).More than 55%of soil loss records revealed soil loss less than the tolerable rate(10 t ha^(−1)).Area closure,perennial vegetation cover,agronomic practices,mechanical erosion control practices,annual cropland cover,and drainage groups of practices led to 74.0±18.3%,69.0±24.6%,66.2±30.5%,66.1±18.0%,63.5±20.0%,and 40±11,1%soil loss reduction,respectively.A yield increase of 25.2±15.0%,37.5±28.0%,and 75.4±85.0%was found from drainage,agronomy,and mechanical erosion control practices,respectively.The average yield loss by erosion on fields without appropriate land management practice and on conserved fields was 26.5±26.0%and 25±3.7%,respectively.The findings suggest that practices that entail a continuous presence of soil cover during the rainy season,perennial vegetation,retention of moisture,and barriers for sediment transport were most effective at decreasing soil loss and increasing productivity.This review provides evidence to identify the best LMP practices for wider adoption and inform decision-making on LMP investments towards achieving sustainable solutions to reverse land degradation.展开更多
Application of simple and locally based erosion assessment methods that fit to the local condition is necessary to improve the performance and efficiency of soil conservation practices. In this study, rill erosion for...Application of simple and locally based erosion assessment methods that fit to the local condition is necessary to improve the performance and efficiency of soil conservation practices. In this study, rill erosion formation and development was investigated on the topo-sequence of three catchments （300-500 m slope length）; and on agricultural fields （6 m and 24 m slope lengths） with different crop-tillage surfaces during erosive storms. Rill density and rill erosion rates were measured using rill cross section survey and close range digital photogrammetry. Rill formation and development was commonly observed on conditions where there is wider terrace spacing, concave slope shapes and unstable stone terraces on steep slopes. At field plot level, rill development was controlled by the distribution and abrupt change in the soil surface roughness and extent of slope length. At catchment scale, however, rill formation and development was controlled by landscape structures, and concavity and convexity of the slope. Greater rill cross sections and many small local rills were associated to the rougher soil surfaces. For instance, relative comparison of crop tillage practices have showed that faba-bean tillage management was more susceptible to seasonal rill erosion followed by Teff and wheat tillage surfaces under no cover condition. Surface roughness and landscape structures played a net decreasing effect on the parallel rill network development. This implies that spatial and temporal variability of the rill prone areas was strongly associated with the nature and initial size of surface micro-topography or tillage roughness. Thus, it is necessary to account land management practices, detail micro-topographic surfaces and landscape structures for improved prediction of rill prone areas under complex topographic conditions. Application of both direct rill cross section survey and close range digital photogrammetric techniques could enhance field erosion assessment for practical soil conservation improvement.展开更多
This study aimed to assess the influence of conservation practices (P) and cover management (C) on soil loss reduction by determining it at the scale of landscape units in 16 systematically selected watersheds. Focusi...This study aimed to assess the influence of conservation practices (P) and cover management (C) on soil loss reduction by determining it at the scale of landscape units in 16 systematically selected watersheds. Focusing on major land management practices implemented through free community labor mobilization, the assessment combined remote sensing techniques, field observation, and expert as well as local knowledge. The results show an average net decrement of 39% ( ± 19%) in the P factor value and 8.9%( ± 21%) in the C factor value after implementation of land management practices. P factor value re-duction is linked to a high area coverage of level structures, while increases in the P factor value are associated with poor quality of structures, inappropriate practices, and wide spacing between structures on steep slopes. C factor value reduction is observed in non-arable shrub- and bushland with enriched area closure, whereas increased C factor values are associated with open access grasslands and untreated croplands. The overall change in P and C factor values resulted in a 42% ( ± 28%) relative soil loss re-duction. The demonstrated approach makes it possible to assess spatial and temporal dynamics in the P and C erosion factors and to estimate spatially disaggregated changes in the P and C factor values. This can help to improve parameterization of inputs for erosion modelling and to assess their relative soil loss effect. The approach provides valuable feedback on watershed planning processes and supports informed decisions regarding the appropriate selection of land management practices.展开更多
Background:Even though increasing population pressure and associated increased demand for food and economic development have led to overexploitation and degradation of wetlands throughout the world,the drivers are mos...Background:Even though increasing population pressure and associated increased demand for food and economic development have led to overexploitation and degradation of wetlands throughout the world,the drivers are most severe in developing countries.For generations,Fogera wetlands in Ethiopia which are parts of Lake Tana Biosphere Reserve have been widely used for grazing of indigenous cattle.Fogera cattle are one of several recognized indigenous breeds of Abyssinian zebu bovine cattle(Bos primigenius indicus)found in Fogera district,Ethiopia.This study was conducted to quantify impacts of rice expansion on cattle population in Fogera wetlands.Data were collected through questionnaire,focus group discussions,interviews,and land use/land cover analysis.Respondents were selected using systematic random sampling.Variance and LEVENES test were used to analyze the livestock unit and to check homogeneity.Results:The study revealed that during the 20-year period preceding 2015,the number of cattle owned decreased from 3509 to 1510 heads.In the same period,rice cultivation increased from 182 to 9499 ha and production from 6701 to 714,013 qt.Grazing lands were reduced from 8550 to 3501 ha,wetlands from 3114 to 1060 ha,and forests from 1542 to 907 ha.Land use/land cover changes showed a negative balance of 40%dry matter requiring cattle feed to be increasingly supplemented through purchases,or reduction in herd number.The study also indicated that the land-use changes brought at the expense of traditional cattle production systems.Conclusion:Hence,proper management is required to maintain these valuable resources and keep their role in socioeconomic development of the area.展开更多
基金supported by the Natural Science Foundation of the Jiangsu Province for Young Scholars,China(BK20130694)the Specialized Research Fund for the Doctoral Program of Higher Education,China(20130097120053)+1 种基金the National Natural Science Foundation of China(31502014)the Project of Jiangsu Independent Innovation,China(CX(15)1003)
文摘The aim of the current study was to investigate the effects of a lactic acid bacteria inoculant（Lactobacillus plantarum, LP）, fibrolytic enzyme（EN）, combination of LP and EN（LP＋EN） on fermentation quality, nutritive characteristics and in vitro digestibility of total mixed ration（TMR） silages containing 0, 7.5 and 15.0%（on dry matter basis） of rape（Brassica campestris L.） straw（RS）（denoted as CTMR, LTMR and MTMR, respectively）. After ensiling for 60 days, TMR silages without additives were well preserved, but MTMR had higher p H than CTMR and LTMR. There were no differences in other parameters of fermentation quality, microbial composition, nutrition and in vitro digestibility between CTMR and LTMR except for yeast and mold number and crude protein（CP） content. CTMR and LTMR silage had higher CP content, in vitro neutral detergent fiber digestibility（IVNDFD） and in vitro acid detergent fiber digestibility（IVADFD）, lower acid detergent fiber（ADF） content than MTMR silage. LP and EN decreased p H and increased dry matter（DM） recovery of TMR silages. LP＋EN improved the fermentation quality, nutritive characteristics and in vitro digestibility of TMR silages, showed by lower p H, ADF content, higher lactic acid content, in vitro dry matter digestibility（IVDMD） and IVNDFD. Therefore, It was suggested that TMR silage contained 7.5% RS on a DM basis and treated with LP＋EN can be as a useful feed for ruminant.
文摘The Lake Tana area is located within a complex volcano-tectonic basin on the northwestern Ethiopian plateau.The basin is underlain by a thick succession of Oligocene transitional basalts and sub-alkaline rhyolites overlain in places,particularly south of the lake,by Quaternary alkaline to mildly transitional basalts,and dotted with Oligo-Miocene trachyte domes and plugs.This paper presents the results of integrated field,petrographic,and major and trace element geochemical studies of the Lake Tana area volcanic rocks,with particular emphasis on the Oligocene basalts and rhyolites.The studies reveal a clear petrogenetic link between the Oligocene basalts and rhyolites.The Oligocene basalts are:(1)plagioclase,olivine,and/or pyroxene phyric;(2)show an overall decreasing trend in MgO,Fe_(2)O_(3),and CaO with silica;(3)have relatively low Mg#,Ni and Cr contents and high Nb/La and Nb/Yb ratios;and(4)show LREE enriched and generally flat HREE patterns.All these imply the origin of the Oligocene basalts by shallow-level fractional crystallization of an enriched magma sourced at the asthenospheric mantle.The Oligocene rhyolites:(1)are enriched in incompatible while depleted in compatible trace elements,P and Ti;(2)show a strong negative Eu anomaly;(3)contain appreciable amounts of plagioclase,apatite,and Fe-Ti oxides;and(4)show clear geochemical similarity with well-constrained rhyolites from the Large Igneous Province(LIP)of the northwestern Ethiopian plateau.Low-pressure fractional crystallization of mantle-derived basaltic magma in crustal magma chambers explains the origin of these rhyolites.Our study further shows that the Oligocene basalts and rhyolites are co-genetic and the felsic rocks of the Lake Tana area are related differentiates of the flood basalt volcanism in the northwestern Ethiopian plateau.
文摘BACKGROUND: Premature rupture of membrane(PROM) is linked to significant maternal prenatal mortalities and morbidity. In Ethiopia, where maternal mortality is still high, the maternal and fetal outcomes in PROM is very important to decrease maternal and child mortality and for better management and prevention of complications. Thus, this study aimed to detect the maternal and fetal outcomes and associated factors in term PROM at Mizan-Aman General Hospital, south-west Ethiopia.METHODS: A retrospective cross sectional study was conducted using data available at MizanAman General Hospital during a period of 3 years(January 2011 to December 2013). We examined records of 4 525 women who gave birth in the hospital; out of these women, 185 were diagnosed with term PROM and all of them were included in the study. The data of these women were collected using a checklist based on registration books. The data were analyzed using SPSS version 20.0 statistical package. The association between independent and dependent variables was assessed by bivariate and multiple logistic regression analyses. 95%CI and P value less than 0.05 were considered statistically signifi cant.RESULTS: Of the 4 525 women who gave birth in the hospital, 202 were complicated by term PROM. About 22.2% of the women showed unfavorable maternal outcomes. The most common cause of maternal morbidity and mortality was puerperal sepsis. About 33.5% of neonates experienced unfavorable outcomes. The duration of PROM >12 hours(AOR=5.6, 95%CI 1.3–24.1) latency >24 hours(AOR=2.8, 95%CI 1.7–11.8), residing in rural areas(AOR=4.2, 95%CI 3.96–29.4) and birth weight less than 2 500 g were associated with unfavorable outcomes.CONCLUSION: Women residing in rural areas, long latency, and neonates with birth weight less 2 500 g may have unfavorable outcomes. Therefore, optimum obstetric and medical care is essential for the reduction of the devastating complications related to disorders.
文摘The Safe Schools Declaration of 2015 is an inter-governmental political agreement signed by several countries designed to protect the schooling of the school-aged population during armed conflicts.Yet,in countries where civil war erupted,schools were demolished.Several school-aged children were either forcibly recruited by governments or coerced by rebel groups to serve in armed fights.As a result,several children were deprived of their education and have remained suffering from deep psychological scars.The central question of the study is:What kind of sustainability-driven school buildings can be initiated in countries that are now enduring peace so that the learning environments are more comfortable and improve the well-being of the war-impacted children and school employees?After reviewing the literature,a strategic conceptual framework that incorporated the synergistic relationship between economic,social,and environmental aspects of sustainability was initiated to map out sustainable school buildings.In short,the conceptual framework proposed to construct school buildings in some of the war-affected developing countries includes assembling cost-efficiency and eco-effectiveness inputs,using renewable energy sources powered by natural sunlight,collecting rainwater in mud cisterns,reducing emissions of carbon oxides,and empowering the local community to be the main actors to design sustainable buildings during the preconstruction,construction,and post-construction stages to serve as learning spaces for the war-affected occupants and their neighborhoods.
基金financial support from the Key Project of NSFC for International Cooperation(No.81420108027,China)the National Natural Science Foundation of China(NSFC Nos.81273354,81573347,81903453)+6 种基金Young Scholars Program of Shandong University(YSPSDU No.2016WLJH32,China)Shandong Provincial Natural Science Foundation(ZR2019BH011,China)China Postdoctoral Science Foundation(2018M640641,2019T120596)Key research and development project of Shandong Province(No.2017CXGC1401,China)KU Leuven(GOA 10/014,Belgium)the Spanish Government(MINECO Project SAF2017-881074-R,AEI/FEDER,UE)Generalitat de Catalunya(2017SGR1746,Spain)for the financial support
文摘In this report,a series of novel piperidine-substituted thiophene[3,2-d]pyrimidine derivatives were designed to explore the hydrophobic channel of the non-nucleoside reverse transcriptase inhibitors binding pocket(NNIBP)by incorporating an aromatic moiety to the left wing of the lead K-5 a2.The newly synthesized compounds were evaluated for anti-HIV potency in MT-4 cells and inhibitory activity to HIV-1 reverse transcriptase(RT).Most of the synthesized compounds exhibited broad-spectrum activity toward wild-type and a wide range of HIV-1 strains carrying single non-nucleoside reverse transcriptase inhibitors(NNRTI)-resistant mutations.Especially,compound 26 exhibited the most potent activity against wild-type and a panel of single mutations(L1001,K103 N,Y181 C,Y188 L and E138 K)with an EC50 ranging from 6.02 to 23.9 nmol/L,which were comparable to those of etravirine(ETR).Moreover,the RT inhibition activity,preliminary structure-activity relationship and molecular docking were also investigated.Furthermore,26 exhibited favorable pharmacokinetics(PK)profiles and with a bioavailability of 33.8%.Taken together,the results could provide valuable insights for further optimization and compound 26 holds great promise as a potential drug candidate for the treatment of HIV-1 infection.
文摘BACKGROUND: Rapid sequence induction and intubation(RSII) is an emergency airway management technique for patients with a risk of pulmonary aspiration. It involves preoxygenation, administration of predetermined doses of induction and paralytic drugs, avoidance of mask ventilation, and laryngoscopy followed by tracheal intubation and keeping cricoid pressure applied till endotracheal tube cuff be inflated. Oxygen desaturation has been seen during RSII. We assessed the incidence of oxygen desaturation during RSII.METHODS: An institution-based observational study was conducted from March 3 to May 4, 2014 in our hospital. All patients who were operated upon under general anesthesia with RSII during the study period were included. A checklist was prepared for data collection.RESULTS: A total of 153 patients were included in this study with a response rate of 91.6%. Appropriate drugs for RSII, equipments for RSII, equipments for diffi cult intubation, suction machine with a catheter, a monitor and an oxygen backup such as ambu bag were not prepared for 41(26.8%), 50(32.7%), 51(33.3%), 38(24.8%) and 25(16.3%) patients respectively. Cricoid pressure was not applied at all for 17(11.1%) patients and 53(34.6%) patients were ventilated after induction of anesthesia but before intubation and endotracheal cuff inflation. A total of 55(35.9%) patients desaturated during RSII(SPO2<95%). The minimum, maximum and mean oxygen desaturations were 26%, 94% and 70.9% respectively. The oxygen desaturation was in the range of <50%, 50%–64%, 65%–74%, 75%–84%, 85%–89 % and 90%–94% for 6(3.9%), 7(4.6%), 5(3.3%), 10(6.5%), 13(8.5%) and 14(9.2%) patients respectively.CONCLUSION: The incidence of oxygen desaturation during RSII was high in our hospital. Preoperative patient optimization and training about the techniques of RSII should be emphasized.
基金The work was funded by the Swedish Energy Agency,the Swedish Science Council and the Knut and Alice Wallenberg foundation(KAW)through generous instrument grants and a Wallenberg Scholar grant to O.I.We acknowledge Anders Elfwing at Linköping University for helpful discussions.
文摘Scalable production methods and low-cost materials with low embodied energy are key to success for organic solar cells.PEDOT(PSS)electrodes meet these criteria and allow for low-cost and all solution-processed solar cells.However,such devices are prone to shunting.In this work we introduce a roll-to-roll lamination method to construct semitransparent solar cells with a PEDOT(PSS)anode and an polyethyleneimine(PEI)modified PEDOT(PSS)cathode.We use the polymer:PCBM active layer coated on the electrodes as the lamination adhesive.Our lamination method efficiently eliminates any shunting.Extended exposure to ambient degrades the laminated devices,which manifests in a significantly reduced photocurrent extraction when the device is illuminated through the anode,despite the fact that the PEDOT(PSS)electrodes are optically equivalent.We show that degradation-induced electron traps lead to increased trap-assisted recombination at the anode side of the device.By limiting the exposure time to ambient during production,degradation is significantly reduced.We show that lamination using the active layer as the adhesive can result in device performance equal to that of conventional sequential coating.
文摘This study examines the effects of industrial parks on export earnings,employment creation,and FDI attraction in Ethiopia.Despite varying degrees of successes and failures,several countries have utilized industrial park and other forms of special economic zones as a policy instrument for fostering economic transformation.China is at the forefront of using special economic zones as a policy tool for economic transformation.Ethiopia is one of the African countries that has adopted industrial park development as a policy tool to enhance its economic transformation.However,the issue is not well researched and this study aims to contribute to fill the research gap.The analysis of the hypotheses test reveals that industrial parks in Ethiopia have statistically significant effects on export earnings,employment creation,and FDI attraction with significant levels of p≤0.001.Low labor productivity,domestic raw material supply constraints,weak forward and backward linkage,transport cost and logistic constraints,and government institutions’capacity constraints are identified as the major constraints that affect the effectiveness of industrial parks and manufacturing firms.On the other hand,the availability of a trainable labor force,raw material potential,preferential policies and incentives,the economic growth of the country,and the labor wage rise in China and other emerging countries are identified as the main five potentials and opportunities for sustained and dynamic industrial parks development.Based on the findings,three policy implications are suggested.First,formulating and implementing manufacturing labor force development and utilization policies and strategies are vital.Second,the forward-backward linkage along the value chain needs to be enhanced through proper policies.Finally,institutional capacity building through learning by doing and public-private partnership has to be strengthened.
文摘A review of the literature indicates that,currently,Ethiopia is now beyond the bounds of fragility.The purpose of the study was to investigate whether Ethiopia was experiencing fragility.After a review of the literature on fragility,a theoretical framework lens on fragility was developed to empirically test Ethiopia’s current condition.A longitudinal analysis indicates that before 2018,Ethiopia was regarded as the central economic engine of sub-Saharan Africa.However,as the current regime reversed Ethiopia’s developmental state model and moved to follow a neo-liberal model,Ethiopia’s economy has gradually diminished.More specifically,during the current regime,Ethiopia has experienced a decline in its Gross Domestic Product,faced rampant unemployment,and encountered an increase in inflation.Its foreign exchange currency reserves have declined below the three-month threshold of hard currency required for a country to import goods and services,and its external debt has extended beyond the country’s GDP.By encouraging armed conflict and widespread insurgencies,the current regime has caused social tension and deep humanitarian crises in Ethiopia-resulting in devastation of health and school facilities and causing more than five million Ethiopians to be displaced.Finally,failing to provide leadership to his people,the current regime in Ethiopia has willingly allowed the incursion of Ethiopia’s sovereignty by foreign forces.The conclusion of the study is that,when observed through the lens of fragility using a longitudinal framework,currently,Ethiopia has traversed beyond fragility and seems to be heading toward balkanization.
文摘Geospatial information acquired with Unmanned Aerial Vehicles(UAV)provides valuable decision-making support in many different domains,and technological advances coincide with a demand for ever more sophisticated data products.One consequence is a research and development focus on more accurately referenced images and derivatives,which has long been a weakness especially of low to medium cost UAV systems equipped with relatively inexpensive inertial measurement unit(IMU)and Global Navigation Satellite System(GNSS)receivers.This research evaluates the positional accuracy of the real-time kinematics(RTK)GNSS on the DJI Matrice 600 Pro,one of the first available and widely used UAVs with potentially surveying-grade performance.Although a very high positional accuracy of the drone itself of 2 to 3 cm is claimed by DJI,the actual accuracy of the drone RTK for positioning the images and for using it for mapping purposes without additional ground control is not known.To begin with,the actual GNSS RTK position of reference center(the physical point on the antenna)on the drone is not indicated,and uncertainty regarding this also exists among the professional user community.In this study the reference center was determined through a set of experiments using the dual frequency static Leica GNSS with RTK capability.The RTK positioning data from the drone were then used for direct georeferencing,and its results were evaluated.Test flights were carried out over a 70 x 70 m area with an altitude of 40 m above the ground,with a ground sampling distance of 1.3 cm.Evaluated against ground control points,the planimetric accuracy of direct georeferencing for the photogrammetric product ranged between 30 and 60 cm.Analysis of direct georeferencing results showed a time delay of up to 0.28 seconds between the drone GNSS RTK and camera image acquisition affecting direct georeferencing results.
文摘Tef is grown as<span> an</span><span> important domestic cereal in Ethiopia. Currently</span><span>,</span><span> global attention is given for it particularly as a </span><span>“</span><span>health food</span><span>”</span><span> due to the absence of gluten and gluten like proteins in its grains. Regardless of its wider adaptation, productivity of tef is low in the country with the national average grain yield of 1.379 tons·ha</span><sup><span style="vertical-align:super;">-1</span></sup><span>. This is mainly because of low soil fertility and severe organic matter depletion intensified by low rate of chemical fertilizer application. This study was conducted to evaluate effects of balanced fertilizers on the yield, yield components of tef and to determine economic feasibility for tef production in Wolaita. The experiment was laid out in a randomized complete block design (RCBD) with sixteen treatments replicated three times. The treatments consist of factorial combinations of four rates of K (Potassium) (0, 25, 50, and 100 kg/ha) and four rates of NPSB (Nitrogen, Phosphorus, Sulfur and Boron) (0, 50, 100, 200 kg/ha) fertilizers. Fertilizer types such as urea (46-0-0), NPSB (18.9-37.7-6.95-0.1) and K (0-0-60) were used as a source of nutrients. The soil analysis result indicated that, most of the nutrients are below optimum level to support the potential crop production. This may be related with reduced farm management practices and continuous cropping with little or no fertilizers input. In this study</span><span>,</span><span> it was found that, the combined application of NPSB and K fertilizers had </span><span>a </span><span>significant effect on growth, yield and yield components of tef. Among the treatments studied, NPSB (100</span><span> </span><span>Kg/ha) and K (50</span><span> </span><span>Kg/ha) gave greater grain yield. Furthermore, this treatment enhanced growth and yield related parameters compared to the control treatment. Thus, it is conceivable to recommend each to attain greater grain yiel
文摘AIM：To assess the pattern of ocular manifestation and associated factors among human immunodeficiency virus（HIV）/acquired immunodeficiency syndrome（AIDS） patients on highly active antiretroviral therapy（HAART） at Hawassa University Referral Hospital, Southern Ethiopia. METHODS：A cross sectional study was conducted from January 2014 to April 2015. After obtaining informed written consent, 240 adult HIV/AIDS patients on HAART were randomly selected regardless of their ophthalmic symptoms, WHO status or CD4 count. Data were collected using structured questionnaires and ophthalmologic clinical examination. Data were entered and analyzed using SPSS version 20.0 software. RESULTS：The mean duration of HAART was 62.5mo. The prevalence of HIV related ocular manifestation was 14.2%. Seborrheic blepharitis（5%） was the most common ocular manifestation, followed by squamoid conjunctival growth（3.8%）. The rate of ocular manifestation was significantly higher among study participants who had CD4＋ count 〈200 cells/μL（AOR=3.83; 95%CI：1.315-11.153）, low duration of HAART（AOR=3.0; 95%CI：1.305-6.891） and who had primary school education [odds ratio（OR） =2.8; 95%CI：1.105-7.099]. Prevalence of visual impairment and blindness was 10.9% and 5.8%, respectively.CONCLUSION：HAART may be the reason for the decline in the prevalence of ocular manifestation in HIV/AIDS patients in the study area. Ophthalmologic screening of HIV/AIDS patients, especially those with CD4 counts of 〈200/μL cells and in the first five years of HAART followup is recommended to reduce visual impairment and/or blindness.
文摘The runoff coefficient (RC) is the ratio between the runoff and rainfall amounts and is scale dependent, which is due in part to the heterogeneity of watershed characteristics. This study quantified the spatial scale effects on runoff using long-term rainfall-runoff data on runoff plots and small watersheds. Effect of spatial scale on RC was studied for 12 runoff plots (2m by 15m) and three small watersheds (113-477 ha) in the highlands of Ethiopia using a total of 4397 and 13,92515-day cumulative pairs of rainfall and runoff data at watershed and runoff plot scales, respectively. The observed average RC of runoff plots was extrapolated based on the extent of representation of a particular watershed in terms of slope, land use, cover and soil type. The weighted RC of plots was then compared with the observed RC of the watershed to determine a scale factor for extrapolation. A decrease in RC from plot to the watershed was observed in Anjeni and Andit Tid watersheds, while an increase in RC in Maybar watershed illustrates the role of specific watershed conditions in determining the scale effect. This, in turn, suggests that the variation in scale factor is not well explained by the difference in the area alone. The scale effect of runoff generation was better explained by extrapolating the RC based on the representation of different watershed characteristics. Thus, extrapolation exercises in runoff modeling and scaling efforts of soil and water conservation practices should consider the scale effect cautiously.
文摘Identifying land management practices(LMPs)that enhance on-site sediment management and crop productivity is crucial for the prevention,reduction,and restoration of land degradation and contributing to achieving land degradation neutrality(LDN).We reviewed studies in Ethiopia to assess the effects of LMPs on soil loss(84 studies)and crop productivity(34 studies)relative to control practice.Yield variability on conserved lands was assessed using 12,796 fixed plot data.Effects of LMP on soil loss were 0.5-55 t ha^(−1)y^(−1)compared to control practices yielding 50 to 140 t ha^(−1)y^(−1).More than 55%of soil loss records revealed soil loss less than the tolerable rate(10 t ha^(−1)).Area closure,perennial vegetation cover,agronomic practices,mechanical erosion control practices,annual cropland cover,and drainage groups of practices led to 74.0±18.3%,69.0±24.6%,66.2±30.5%,66.1±18.0%,63.5±20.0%,and 40±11,1%soil loss reduction,respectively.A yield increase of 25.2±15.0%,37.5±28.0%,and 75.4±85.0%was found from drainage,agronomy,and mechanical erosion control practices,respectively.The average yield loss by erosion on fields without appropriate land management practice and on conserved fields was 26.5±26.0%and 25±3.7%,respectively.The findings suggest that practices that entail a continuous presence of soil cover during the rainy season,perennial vegetation,retention of moisture,and barriers for sediment transport were most effective at decreasing soil loss and increasing productivity.This review provides evidence to identify the best LMP practices for wider adoption and inform decision-making on LMP investments towards achieving sustainable solutions to reverse land degradation.
基金the Austrian Academic Exchange Service (OAD) for financially supporting this study
文摘Application of simple and locally based erosion assessment methods that fit to the local condition is necessary to improve the performance and efficiency of soil conservation practices. In this study, rill erosion formation and development was investigated on the topo-sequence of three catchments （300-500 m slope length）; and on agricultural fields （6 m and 24 m slope lengths） with different crop-tillage surfaces during erosive storms. Rill density and rill erosion rates were measured using rill cross section survey and close range digital photogrammetry. Rill formation and development was commonly observed on conditions where there is wider terrace spacing, concave slope shapes and unstable stone terraces on steep slopes. At field plot level, rill development was controlled by the distribution and abrupt change in the soil surface roughness and extent of slope length. At catchment scale, however, rill formation and development was controlled by landscape structures, and concavity and convexity of the slope. Greater rill cross sections and many small local rills were associated to the rougher soil surfaces. For instance, relative comparison of crop tillage practices have showed that faba-bean tillage management was more susceptible to seasonal rill erosion followed by Teff and wheat tillage surfaces under no cover condition. Surface roughness and landscape structures played a net decreasing effect on the parallel rill network development. This implies that spatial and temporal variability of the rill prone areas was strongly associated with the nature and initial size of surface micro-topography or tillage roughness. Thus, it is necessary to account land management practices, detail micro-topographic surfaces and landscape structures for improved prediction of rill prone areas under complex topographic conditions. Application of both direct rill cross section survey and close range digital photogrammetric techniques could enhance field erosion assessment for practical soil conservation improvement.
文摘This study aimed to assess the influence of conservation practices (P) and cover management (C) on soil loss reduction by determining it at the scale of landscape units in 16 systematically selected watersheds. Focusing on major land management practices implemented through free community labor mobilization, the assessment combined remote sensing techniques, field observation, and expert as well as local knowledge. The results show an average net decrement of 39% ( ± 19%) in the P factor value and 8.9%( ± 21%) in the C factor value after implementation of land management practices. P factor value re-duction is linked to a high area coverage of level structures, while increases in the P factor value are associated with poor quality of structures, inappropriate practices, and wide spacing between structures on steep slopes. C factor value reduction is observed in non-arable shrub- and bushland with enriched area closure, whereas increased C factor values are associated with open access grasslands and untreated croplands. The overall change in P and C factor values resulted in a 42% ( ± 28%) relative soil loss re-duction. The demonstrated approach makes it possible to assess spatial and temporal dynamics in the P and C erosion factors and to estimate spatially disaggregated changes in the P and C factor values. This can help to improve parameterization of inputs for erosion modelling and to assess their relative soil loss effect. The approach provides valuable feedback on watershed planning processes and supports informed decisions regarding the appropriate selection of land management practices.
文摘Background:Even though increasing population pressure and associated increased demand for food and economic development have led to overexploitation and degradation of wetlands throughout the world,the drivers are most severe in developing countries.For generations,Fogera wetlands in Ethiopia which are parts of Lake Tana Biosphere Reserve have been widely used for grazing of indigenous cattle.Fogera cattle are one of several recognized indigenous breeds of Abyssinian zebu bovine cattle(Bos primigenius indicus)found in Fogera district,Ethiopia.This study was conducted to quantify impacts of rice expansion on cattle population in Fogera wetlands.Data were collected through questionnaire,focus group discussions,interviews,and land use/land cover analysis.Respondents were selected using systematic random sampling.Variance and LEVENES test were used to analyze the livestock unit and to check homogeneity.Results:The study revealed that during the 20-year period preceding 2015,the number of cattle owned decreased from 3509 to 1510 heads.In the same period,rice cultivation increased from 182 to 9499 ha and production from 6701 to 714,013 qt.Grazing lands were reduced from 8550 to 3501 ha,wetlands from 3114 to 1060 ha,and forests from 1542 to 907 ha.Land use/land cover changes showed a negative balance of 40%dry matter requiring cattle feed to be increasingly supplemented through purchases,or reduction in herd number.The study also indicated that the land-use changes brought at the expense of traditional cattle production systems.Conclusion:Hence,proper management is required to maintain these valuable resources and keep their role in socioeconomic development of the area.
