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Introduction: Antibiotic resistance is the main factor influencing the ef-ficacy of treatments to eradicate the infection by Helicobacter pylori (H. pylori). The treatments including clarithromycin are the most frequently used in first-line ; however, the bacterial resistance to clarithromycin in treatment-naïve patients in Europe is, overall, >20%.Aims & Methods: To assess the effectiveness of first-line H. pylori treat- ments in Europe according to the resistance to clarithromycin.Non-interventional, prospective, multicenter, international European re-gistry on the management of H. pylori (Hp-EuReg). All culture-diagnosed infected adult patients were registered at AEG-REDCap e-CRF from 2013 to 2021. Per-protocol (PP) analysis was performed based on the presence or absence of bacterial resistance to clarithromycin in treatment-naïve pati-ents. The data was subject to quality control.Results: In total, 2, 479 culture-naïve patients were included. Of these, 627 (25%) reported resistance to clarithromycin. The eradication rate with the standard triple therapy (PPI+clarithromycin+amoxicillin) in patients susceptible to clarithromycin was 92% (424/460). The eradication rate in these clarithromycin-susceptible patients was higher both with the con-comitant regimen (PPI+clarithromycin+amoxicillin+metronidazole) and with the sequential treatment with tinidazole (95%, 882/929), and also with the bismuth quadruple regimen (PPI+bismuth+tetracycline+metronidazole) as single capsule (100%, 67/67) (p

Nile Tilapia, Oreochromis niloticus, is one of important commercial fish in Africa and other tropical regions. In Ethiopia, it accounts for more than 60% of the total annual landings. In Lake Hawassa, one of the rift valley lakes in Ethiopia, it even mounts to more than 85%. However, recently, the yield in the lake dropped to about 50% of its historical maximum, indicative of a dwindling population size resulting from overfishing. This research aimed at assessing the sustainable potential yield of tilapia in Lake Hawassa. Data were collected for one year, on a daily basis, from the commercial fishery. The growth parameters (L∞ and K), the total population (N) and the fishing mortality (F) were estimated using FiSAT II. The maximum sustainable and economic yields (MSY & MEY) and the corresponding fishing effort were determined using the length-based Thompson & Bell bio-economic model. Accordingly, the MSY was estimated at 466.3 tonnes per year. Our findings will be instrumental to prepare a fishery management plan for the lake. The procedure can also be applied to assess the fish stock of the other rift valley lakes.

ispartof: pages:10-15 ispartof: Excursion guide of the TropiLakes 2015 mid-conference excursion. Bahir Dar, Ethiopia: Bahir Dar University pages:10-15 ispartof: International ConferenceTropilakes 2015. Bahir Dar University, Bahir Dar, Ethiopia location:Ethiopia date:23 Sep - 29 Sep 2015 status: published

© 2016 Elsevier B.V. Gully erosion has important on and off site effects. Therefore, several studies have been conducted over the past decades to quantify gully headcut retreat (GHR) in different environments. Although these led to important site-specific and regional insights, the overall importance of this erosion process or the factors that control it at a global scale remain poorly understood. This study aims to bridge this gap by reviewing research on GHR and conducting a meta-analysis of measured GHR rates worldwide. Through an extensive literature review, GHR rates for 933 individual and actively retreating gullies have been compiled from more than 70 study areas worldwide (comprising a total measuring period of >19 600 years). Each GHR rate was measured through repeated field surveys and/or analyses of aerial photographs over a period of at least one year (maximum: 97 years, median: 17 years). The data show a very large variability, both in terms of gully dimensions (cross-sectional areas ranging between 0.11 and 816 m2 with a median of 4 m2) and volumetric GHR rates (ranging between 0.002 and 47 430 m3 year- 1 with a median of 2.2 m3 year- 1). Linear GHR rates vary between 0.01 and 135 m year- 1 (median: 0.89 m year- 1), while areal GHR rates vary between 0.01 and 3628 m2 year- 1 (median: 3.12 m2 year- 1). An empirical relationship allows estimating volumetric retreat rates from areal retreat rates with acceptable uncertainties. By means of statistical analyses for a subset of 724 gullies with a known contributing area, we explored the factors most relevant in explaining the observed 7 orders of magnitudes of variation in volumetric GHR rates. Results show that measured GHR rates are significantly correlated to the runoff contributing area of the gully (r2 = 0.15) and the rainy day normal (RDN; i.e. the long-term average annual rainfall depth divided by the average number of rainy days; r2 = 0.47). Other factors (e.g. land use or soil type) showed no significant correlation with the observed GHR rates. This may be attributed to the uncertainties associated with accurately quantifying these factors. In addition, available time series data demonstrate that GHR rates are subject to very large year-to-year variations. As a result, average GHR rates measured over short (100%) uncertainties. We integrated our findings into a weighted regression model that simulates the volumetric retreat rate of a gully headcut as a function of upstream drainage area and RDN. When weighing each GHR observation proportional to its measuring period, this model explains 68% of the observed variance in GHR rates at a global scale. For 76% of the monitored gullies, the simulated GHR values deviate less than one order of magnitude from their corresponding observed value. Our model clearly indicates that GHR rates are very sensitive to rainfall intensity. Since these intensities are expected to increase in most areas as a result of climate change, our results suggest that gully erosion worldwide will become more intense and widespread in the following decades. Finally, we discuss research topics that will help to address these challenges.

The use of drainage ditches on sloping farmland has an impact on the farmland itself and on the downstream area, though its environmental impacts are not unequivocal. Researchers are still divided about the balance of the positive and negative effects which can be both on-site and off-site. A case study area was chosen around Wanzaye (North Ethiopia) where three different cropland-management practices were studied in 75 catchments: (i) the catchment-wide use of stone bunds on the contour, (ii) the use of slightly sloping drainage furrows (feses), and (iii) the combined use of stone bunds and feses. Three trends in cropland management around Wanzaye and the wider region are observed: (i) feses are exclusively made on rather steep slopes where small drainage areas lead to the rapid development of gully heads; (ii) stone bunds are constructed on both steeper and gentle sloping cropland; and (iii) larger and gently sloping catchments seem to be most suitable for the combined use of drainage ditches and stone bunds. A standardized procedure for topographical threshold analysis was applied to study the impact of different land management practices on gully head development in cropland. Topographical thresholds for gully head development reflect the vulnerability of lands to gullying, i.e. s > kA-b, where s represents slope gradient of the soil surface and A the drainage area at the gully head, b an exponent, and k the resistance of the land to gully head development. The lowest k-values are found for feses catchments, which implies that catchments with the exclusive use of drainage ditches are the most vulnerable to gully head development compared to mixed catchments and stone bund catchments. Yet, on-site sheet and rill erosion are reduced by the use of feses as they reduce the runoff gradient., The use of drainage ditches on sloping farmland has an impact on the farmland itself and on the downstream area, though its environmental impacts are not unequivocal. Researchers are still divided about the balance of the positive and negative effects which can be both on-site and off-site. A case study area was chosen around Wanzaye (North Ethiopia) where three different cropland-management practices were studied in 75 catchments: (i) the catchment-wide use of stone bunds on the contour, (ii) the use of slightly sloping drainage furrows (feses), and (iii) the combined use of stone bunds and feses. Three trends in cropland management around Wanzaye and the wider region are observed: (i) feses are exclusively made on rather steep slopes where small drainage areas lead to the rapid development of gully heads; (ii) stone bunds are constructed on both steeper and gentle sloping cropland; and (iii) larger and gently sloping catchments seem to be most suitable for the combined use of drainage ditches and stone bunds. A standardized procedure for topographical threshold analysis was applied to study the impact of different land management practices on gully head development in cropland. Topographical thresholds for gully head development reflect the vulnerability of lands to gullying, i.e. s > kA-b, where s represents slope gradient of the soil surface, and A the drainage area at the gully head, b an exponent, and k the resistance of the land to gully head development. The lowest k-values are found for feses catchments, which implies that catchments with the exclusive use of drainage ditches are the most vulnerable to gully head development compared to mixed catchments and stone bund catchments. Yet, on-site sheet and rill erosion are reduced by the use of feses as they reduce the runoff gradient.

Gully cut-and-fill dynamics are often thought to be driven by climate and/or deforestation related to population pressure. However, in this case-study of nine representative catchments in the North Ethiopian Highlands, we find that neither climate changes nor deforestation can explain gully morphology changes over the 20th century. Firstly, by using a Monte Carlo simulation to estimate historical catchment-wide curve numbers, we show that the landscape was already heavily degraded in the 19th and early 20th century - a period with low population density. The mean catchment-wide curve number (>80) one century ago was, under the regional climatic conditions, already resulting in considerable simulated historical runoff responses. Secondly, 20th century land cover and runoff coefficient changes were confronted with 20th century changing gully morphologies. As the results show, large-scale land cover changes and deforestation cannot explain the observed processes. The study therefore invokes interactions between authigenic factors, small-scale plot boundary changes, cropland management and sociopolitical forces to explain the gully cut processes. Finally, semi-structured interviews and sedistratigraphic analysis of three filled gullies confirm the dominant impact of (crop)land management (tillage, check dams in gullies and channel diversions) on gully cut-and-fill processes. Since agricultural land management - including land tenure and land distribution - has been commonly neglected in earlier related research, we argue therefore that it can be a very strong driver of 20th century gully morphodynamics.

Gully cut-and-fill dynamics are often thought to be driven by climate and/or deforestation related to population pressure. However, in this case-study of nine representative catchments in the Northern Ethiopian Highlands, we find that neither climate changes nor deforestation can explain gully morphology changes over the twentieth century. Firstly, by using a Monte Carlo simulation to estimate historical catchment-wide curve numbers, we show that the landscape was already heavily degraded in the nineteenth and early twentieth century – a period with low population density. The mean catchment-wide curve number (> 80) one century ago was, under the regional climatic conditions, already resulting in considerable simulated historical runoff responses. Secondly, twentieth century land-cover and runoff coefficient changes were confronted with twentieth century changing gully morphologies. As the results show, large-scale land-cover changes and deforestation cannot explain the observed processes. The study therefore invokes interactions between authigenic factors, small-scale plot boundary changes, cropland management and sociopolitical forces to explain the gully cut processes. Finally, semi-structured interviews and sedistratigraphic analysis of three filled gullies confirm the dominant impact of (crop)land management (tillage, check dams in gullies and channel diversions) on gully cut-and-fill processes. Since agricultural land management – including land tenure and land distribution – has been commonly neglected in earlier related research, we argue therefore that it can be a very strong driver of twentieth century gully morphodynamics.

The combination of runoff-generating areas (saturated soils) and overland flow concentration in features such as drainage ditches makes sloping farmland vulnerable to soil erosion. The establishment of drainage ditches aims at draining the excess of water from the farmland, particularly in areas where soils are saturated in the rainy season. The hydrogeomorphic impacts on the farmland itself and on downstream areas need however also to be studied. Off site, downstream problems comprise higher peak discharges, leading to gully initiation, an increase in sediment load, and flooding problems. On-site problems such as the development of the drainage ditches into (ephemeral) gullies are less documented, although they may be important, as illustrated in the Lake Tana Basin (Ethiopia). The similarities and interactions between ephemeral gully channels and drainage ditches have to be considered to better understand all effects of drainage. Drainage ditches are a potential source of conflict between farmers with different interests and power, as well as between upstream and downstream users. A case study on drainage ditches on sloping farmlands in the Lake Tana Basin showed that nine out of ten catchments had drainage densities by ditches ranging from 53 to 510 m ha−1. Drainage ditches were constructed with an average top width of 27 (±9) cm. A significant correlation was found between stone bund density (physical conservation structures) and ditch drainage density (R = −0·72), in line with the Ethiopian government's ban on drainage ditches in farmlands where stone bunds have been constructed. Copyright © 2014 John Wiley & Sons, Ltd.

A hydrogeological study was undertaken in the Zenako-Argaka catchment, near Hagere Selam in Tigray, northern Ethiopia, during the rainy season of 2006. A geological map was produced through geophysical measurements and ?eld observations, and a fracture zone identi?ed in the north west of the catchment. A perched water table was found within the Trap Basalt series above the laterized upper Aram Aradam Sandstones. A map of this water table was compiled. Water-level variation during the measurement period was at least 4.5m. Variation in basal ?ow for the whole catchment for the measurement period was between 12 and 276m3/day. A groundwater ?ow model was produced using Visual MODFLOW, indicating the general direction of ?ow to be towards the south, and illustrating that the waterways have only a limited in?uence on groundwater ?ow. The soil water budget was calculated for the period 1995-2006, which showed the important in?uence of the distribution of rainfall in time. Although Hagere Selam received some 724mm of rainfall per year over this period, the strong seasonal variation in rainfall meant there was a water de?cit for on average 10months per year.

Metadata only record The aim of conservation agriculture (CA) is to improve soil quality and crop yield whilst reducing runoff and topsoil erosion. An experiment was carried out in a rainfed field using a permanent raised bed planting system for three years (2005-2007) in Adigudem, northern Ethiopia in order to evaluate the effect of CA on runoff, soil loss and crop yield. CA practices were introduced in fields with Vertisols in a randomized complete block design on permanent 5×19 meter plots. Three treatments were evaluated: (1) conventional tillage (CT) with a minimum of three tillage operations and removal of crop residues, (2) terwah (TER) that was similar to CT except that contour furrows were included at 1.5 meter intervals, and (3) derdero+ (DER+), which consists of permanent raised beds with a furrow and bed system, retention of 30% of standing crop residues and zero tillage on the top of the bed. All ploughing as well as the maintenance of the furrows of the permanent raised beds was done using a local ard plough called maresha. Results from monitoring over 3 yr showed that soil loss and runoff were significantly higher (P