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Sample records for blue nile basin

  1. Hydrological characterization of watersheds in the Blue Nile Basin

    OpenAIRE

    S. G. Gebrehiwot; Ilstedt, U.; Gärdenas, A. I.; Bishop, K.

    2010-01-01

    We made a hydrological characterization of 32 watersheds (31–4350 km2) in the Blue Nile Basin, using data from a study of water and land resources in the Blue Nile Basin, Ethiopia published in 1964 by the US Bureau of Reclamation (USBR). The USBR document contains data on flow, climate, topography, geology, soil type, and land use for the period from 1959 to 1963. The aim of the study was to identify which combination of watershed variables best explain the variati...

  2. Hydrology and forests in the Blue Nile basin

    OpenAIRE

    Gebrehiwot, Solomon Gebreyohannis

    2012-01-01

    Forest cover change is considered a major cause of water scarcity during the dry season in the Blue Nile River Basin of Ethiopia, which is part of the Nile River system. However, this is an over-simplification of the complex reality of forest and flow relationships, especially in the tropics. The objectives of this study were to explore the spatial relationship of land use and flow regime, detect temporal changes in the hydrological regime, determine changes in the forest cover, and summarize...

  3. Sediment balances in the Blue Nile River Basin

    Institute of Scientific and Technical Information of China (English)

    Yasir SAALI; Alessandra CROSATO; Yasir AMOHAMED; Seifeldin HABDALLA; Nigel GWRIGHT

    2014-01-01

    Rapid population growth in the upper Blue Nile basin has led to fast land-use changes from natural forest to agricultural land. This resulted in speeding up the soil erosion process in the highlands and increasing sedimentation further downstream in reservoirs and irrigation canals. At present, several dams are planned across the Blue Nile River in Ethiopia and the Grand Ethiopian Renaissance Dam is currently under construction near the border with Sudan. This will be the largest hydroelectric power plant in Africa. The objective of this paper is to quantify the river flows and sediment loads along the Blue Nile River network. The Soil and Water Assessment Tool was used to estimate the water flows from un-gauged sub-basins. To assess model performance, the estimated sediment loads were compared to the measured ones at selected locations. For the gauged sub-basins, water flows and sediment loads were derived from the available flow and sediment data. To fill in knowledge gaps, this study included a field survey in which new data on suspended solids and flow discharge were collected along the Blue Nile and on a number of tributaries. The comparison between the results of this study and previous estimates of the sediment load of the Blue Nile River at El Deim, near the Ethiopian Sudanese border, show that the sediment budgets have the right order of magnitude, although some uncertainties remain. This gives confidence in the results of this study providing the first sediment balance of the entire Blue Nile catchment at the sub-basin scale.

  4. Hydrological characterization of watersheds in the Blue Nile Basin, Ethiopia

    OpenAIRE

    S. G. Gebrehiwot; Ilstedt, U.; Gärdenas, A. I.; Bishop, K.

    2011-01-01

    Thirty-two watersheds (31–4350 km2), in the Blue Nile Basin, Ethiopia, were hydrologically characterized with data from a study of water and land resources by the US Department of Interior, Bureau of Reclamation (USBR) published in 1964. The USBR document contains data on flow, topography, geology, soil type, and land use for the period 1959 to 1963. The aim of the study was to identify watershed variables best explaining the variation in the hydrological regime, with a...

  5. Understanding Catchment Processes and Hydrological Modelling in the Abay/Upper Blue Nile Basin, Ethiopia

    NARCIS (Netherlands)

    Gebrekristos, S.T.

    2015-01-01

    The water resources in the Abay/Upper Blue Nile basin are the source of life for the several hundred million people living in the basin and further downstream. It provides more than 60% of the total Nile water. Intensive farming in unfavourable soils and slopes, overgrazing and soil erosion is among

  6. Hydrological characterization of watersheds in the Blue Nile Basin

    Directory of Open Access Journals (Sweden)

    S. G. Gebrehiwot

    2010-07-01

    Full Text Available We made a hydrological characterization of 32 watersheds (31–4350 km2 in the Blue Nile Basin, using data from a study of water and land resources in the Blue Nile Basin, Ethiopia published in 1964 by the US Bureau of Reclamation (USBR. The USBR document contains data on flow, climate, topography, geology, soil type, and land use for the period from 1959 to 1963. The aim of the study was to identify which combination of watershed variables best explain the variation in the hydrological regime, with special focus to low flow and, what kind of land use low flow might benefit from. Principal Component Analysis (PCA and Partial Least Square (PLS were used to analyze the relationship between hydrologic variables (total flow, maximum flow, minimum flow, runoff coefficient, and low flow index and 30 potential watershed variables. We found that three groups of watershed variables – climate and topography, geology and soil, and land use had almost equal influence on the variation in the hydrologic variables (R2 values ranging from 0.3 to 0.5. The individual variables which were selected based on statistical significance from all groups of explanatory variables were better in explaining the variation. Low flow was positively correlated most strongly to wetland, wood land, rainfall, luvisols, and alluvial soils. Low flow was negatively correlated to grazing land, bush land, tuffs/basalts, eutric-vertisols and riverine forest. We concluded that low flow benefits from the land use types that preserve soil quality and water storage, such as wetland, savannah and woodland, while it was lower in land use resulting in soil degradation. Therefore it provides support to the theory that some land use such as grassland, can promote higher low flow

  7. Hydrological characterization of watersheds in the Blue Nile Basin, Ethiopia

    Directory of Open Access Journals (Sweden)

    S. G. Gebrehiwot

    2011-01-01

    Full Text Available Thirty-two watersheds (31–4350 km2, in the Blue Nile Basin, Ethiopia, were hydrologically characterized with data from a study of water and land resources by the US Department of Interior, Bureau of Reclamation (USBR published in 1964. The USBR document contains data on flow, topography, geology, soil type, and land use for the period 1959 to 1963. The aim of the study was to identify watershed variables best explaining the variation in the hydrological regime, with a special focus on low flows. Moreover, this study aimed to identify variables that may be susceptible to management policies for developing and securing water resources in dry periods. Principal Component Analysis (PCA and Partial Least Square (PLS were used to analyze the relationship between five hydrologic response variables (total flow, high flow, low flow, runoff coefficient, low flow index and 30 potential explanatory watershed variables. The explanatory watershed variables were classified into three groups: land use, climate and topography as well as geology and soil type. Each of the three groups had almost equal influence on the variation in hydrologic variables (R2 values ranging from 0.3 to 0.4. Specific variables from within each of the three groups of explanatory variables were better in explaining the variation. Low flow and low flow index were positively correlated to land use types woodland, dense wet forest and savannah grassland, whereas grazing land and bush land were negatively correlated. We concluded that extra care for preserving low flow should be taken on tuffs/basalts which comprise 52% of the Blue Nile Basin. Land use management plans should recognize that woodland, dense wet forest and savannah grassland can promote higher low flows, while grazing land diminishes low flows.

  8. Understanding Catchment Processes and Hydrological Modelling in the Abay/Upper Blue Nile Basin, Ethiopia

    OpenAIRE

    Gebrekristos, S.T.

    2015-01-01

    The water resources in the Abay/Upper Blue Nile basin are the source of life for the several hundred million people living in the basin and further downstream. It provides more than 60% of the total Nile water. Intensive farming in unfavourable soils and slopes, overgrazing and soil erosion is among the major problems in the basin. Land degradation as a result of soil erosion decreases soil fertility in the upper catchments and simultaneously increases sedimentation in reservoirs and irrigati...

  9. Diurnal rainfall variability over the Upper Blue Nile Basin: a remote sensing based approach

    NARCIS (Netherlands)

    Rientjes, Tom H.M.; Haile, A.T.; Fenta, A.A.

    2012-01-01

    In this study we aim to assess the diurnal cycle of rainfall across the Upper Blue Nile (UBN) basin using satellite observations from Tropical Rainfall Measuring Mission (TRMM). Seven years (2002-2008) of Precipitation Radar (PR) and TRMM Microwave Imager (TMI) data are used and analyses are based o

  10. Analyzing runoff processes through conceptual hydrological modelling in the Upper Blue Nile basin, Ethiopia

    Science.gov (United States)

    Dessie, M.; Verhoest, N. E. C.; Pauwels, V. R. N.; Admasu, T.; Poesen, J.; Adgo, E.; Deckers, J.; Nyssen, J.

    2014-05-01

    Understanding runoff processes in a basin is of paramount importance for the effective planning and management of water resources, in particular in data scarce regions of the Upper Blue Nile. Hydrological models representing the underlying hydrological processes can predict river discharges from ungauged catchments and allow for an understanding of the rainfall-runoff processes in those catchments. In this paper, such a conceptual process-based hydrological model is developed and applied to the upper Gumara and Gilgel Abay catchments (both located within the Upper Blue Nile basin, the Lake Tana sub-basin) to study the runoff mechanisms and rainfall-runoff processes in the basin. Topography is considered as a proxy for the variability of most of the catchment characteristics. We divided the catchments into different runoff production areas using topographic criteria. Impermeable surfaces (rock outcrops and hard soil pans, common in the Upper Blue Nile basin) were considered separately in the conceptual model. Based on model results, it can be inferred that about 65% of the runoff appears in the form of interflow in the Gumara study catchment, and baseflow constitutes the larger proportion of runoff (44-48%) in the Gilgel Abay catchment. Direct runoff represents a smaller fraction of the runoff in both catchments (18-19% for the Gumara, and 20% for the Gilgel Abay) and most of this direct runoff is generated through infiltration excess runoff mechanism from the impermeable rocks or hard soil pans. The study reveals that the hillslopes are recharge areas (sources of interflow and deep percolation) and direct runoff as saturated excess flow prevails from the flat slope areas. Overall, the model study suggests that identifying the catchments into different runoff production areas based on topography and including the impermeable rocky areas separately in the modeling process mimics well the rainfall-runoff process in the Upper Blue Nile basin and brings a useful result

  11. Analyzing runoff processes through conceptual hydrological modeling in the Upper Blue Nile Basin, Ethiopia

    Science.gov (United States)

    Dessie, M.; Verhoest, N. E. C.; Pauwels, V. R. N.; Admasu, T.; Poesen, J.; Adgo, E.; Deckers, J.; Nyssen, J.

    2014-12-01

    Understanding runoff processes in a basin is of paramount importance for the effective planning and management of water resources, in particular in data-scarce regions such as the Upper Blue Nile. Hydrological models representing the underlying hydrological processes can predict river discharges from ungauged catchments and allow for an understanding of the rainfall-runoff processes in those catchments. In this paper, such a conceptual process-based hydrological model is developed and applied to the upper Gumara and Gilgel Abay catchments (both located within the Upper Blue Nile Basin, the Lake Tana sub-basin) to study the runoff mechanisms and rainfall-runoff processes in the basin. Topography is considered as a proxy for the variability of most of the catchment characteristics. We divided the catchments into different runoff production areas using topographic criteria. Impermeable surfaces (rock outcrops and hard soil pans, common in the Upper Blue Nile Basin) were considered separately in the conceptual model. Based on model results, it can be inferred that about 65% of the runoff appears in the form of interflow in the Gumara study catchment, and baseflow constitutes the larger proportion of runoff (44-48%) in the Gilgel Abay catchment. Direct runoff represents a smaller fraction of the runoff in both catchments (18-19% for the Gumara, and 20% for the Gilgel Abay) and most of this direct runoff is generated through infiltration excess runoff mechanism from the impermeable rocks or hard soil pans. The study reveals that the hillslopes are recharge areas (sources of interflow and deep percolation) and direct runoff as saturated excess flow prevails from the flat slope areas. Overall, the model study suggests that identifying the catchments into different runoff production areas based on topography and including the impermeable rocky areas separately in the modeling process mimics the rainfall-runoff process in the Upper Blue Nile Basin well and yields a useful

  12. Analyzing runoff processes through conceptual hydrological modelling in the Upper Blue Nile basin, Ethiopia

    Directory of Open Access Journals (Sweden)

    M. Dessie

    2014-05-01

    Full Text Available Understanding runoff processes in a basin is of paramount importance for the effective planning and management of water resources, in particular in data scarce regions of the Upper Blue Nile. Hydrological models representing the underlying hydrological processes can predict river discharges from ungauged catchments and allow for an understanding of the rainfall–runoff processes in those catchments. In this paper, such a conceptual process-based hydrological model is developed and applied to the upper Gumara and Gilgel Abay catchments (both located within the Upper Blue Nile basin, the Lake Tana sub-basin to study the runoff mechanisms and rainfall–runoff processes in the basin. Topography is considered as a proxy for the variability of most of the catchment characteristics. We divided the catchments into different runoff production areas using topographic criteria. Impermeable surfaces (rock outcrops and hard soil pans, common in the Upper Blue Nile basin were considered separately in the conceptual model. Based on model results, it can be inferred that about 65% of the runoff appears in the form of interflow in the Gumara study catchment, and baseflow constitutes the larger proportion of runoff (44–48% in the Gilgel Abay catchment. Direct runoff represents a smaller fraction of the runoff in both catchments (18–19% for the Gumara, and 20% for the Gilgel Abay and most of this direct runoff is generated through infiltration excess runoff mechanism from the impermeable rocks or hard soil pans. The study reveals that the hillslopes are recharge areas (sources of interflow and deep percolation and direct runoff as saturated excess flow prevails from the flat slope areas. Overall, the model study suggests that identifying the catchments into different runoff production areas based on topography and including the impermeable rocky areas separately in the modeling process mimics well the rainfall–runoff process in the Upper Blue Nile basin

  13. A multi basin SWAT model analysis of runoff and sedimentation in the Blue Nile, Ethiopia

    Directory of Open Access Journals (Sweden)

    Z. M. Easton

    2010-10-01

    Full Text Available A multi basin analysis of runoff and erosion in the Blue Nile Basin, Ethiopia was conducted to elucidate sources of runoff and sediment. Erosion is arguably the most critical problem in the Blue Nile Basin, as it limits agricultural productivity in Ethiopia, degrades benthos in the Nile, and results in sedimentation of dams in downstream countries. A modified version of the Soil and Water Assessment Tool (SWAT model was developed to predict runoff and sediment losses from the Ethiopian Blue Nile Basin. The model simulates saturation excess runoff from the landscape using a simple daily water balance coupled to a topographic wetness index in ways that are consistent with observed runoff processes in the basin. The spatial distribution of landscape erosion is thus simulated more correctly. The model was parameterized in a nested design for flow at eight and sediment at three locations in the basin. Subbasins ranged in size from 1.3 to 174 000 km2, and interestingly, the partitioning of runoff and infiltrating flow could be predicted by topographic information. Model predictions showed reasonable accuracy (Nash Sutcliffe Efficiencies ranged from 0.53–0.92 with measured data across all sites except Kessie, where the water budget could not be closed; however, the timing of flow was well captured. Runoff losses increased with rainfall during the monsoonal season and were greatest from areas with shallow soils and large contributing areas. Analysis of model results indicate that upland landscape erosion dominated sediment delivery to the main stem of the Blue Nile in the early part of the growing season when tillage occurs and before the soil was wetted up and plant cover was established. Once plant cover was established in mid August landscape erosion was negligible and sediment export was dominated by channel processes and re-suspension of landscape sediment deposited early in the growing season. These results imply that targeting small

  14. A multi basin SWAT model analysis of runoff and sedimentation in the Blue Nile, Ethiopia

    Directory of Open Access Journals (Sweden)

    Z. M. Easton

    2010-06-01

    Full Text Available A multi basin analysis of runoff and erosion in the Blue Nile Basin, Ethiopia was conducted to elucidate sources of runoff and sediment. Erosion is arguably the most critical problem in the Blue Nile Basin, as it limits agricultural productivity in Ethiopia, degrades benthos in the Nile, and results in sedimentation of dams in downstream countries. A modified version of the Soil and Water Assessment Tool (SWAT model was developed to predict runoff and sediment losses from the Ethiopian Blue Nile Basin. The model simulates saturation excess runoff from the landscape using a simple daily water balance coupled to a wetness index in ways that are consistent with observed runoff processes in the basin. The spatial distribution of landscape erosion is thus simulated more correctly. The model was parameterized in a nested design for flow at eight and sediment at two subbasin locations in the basin. Subbasins ranged in size from 4.8 to 174 000 km2, and interestingly, the partitioning of runoff and infiltrating flow could be predicted by topographic information. Model predictions showed reasonable accuracy (Nash Sutcliffe Efficiencies ranged from 0.53–0.92 with measured data across all sites except Kessie, where the water budget could not be closed; however, the timing of flow was well captured. Runoff losses increased with rainfall during the monsoonal season and were greatest from shallow soils. Analysis of model results indicate that upland landscape erosion dominated sediment delivery to the main stem of the Blue Nile in the early part of the growing season before the soil was wetted up and plant cover was established. Once plant cover was established in mid August landscape erosion was negligible and sediment export was dominated by channel processes and re-suspension of landscape sediment deposited early in the growing season. These results imply that targeting small areas of the landscape where runoff is produced can be the most

  15. Diurnal rainfall variability over the Upper Blue Nile Basin: A remote sensing based approach

    Science.gov (United States)

    Rientjes, Tom; Haile, Alemseged Tamiru; Fenta, Ayele Almaw

    2013-04-01

    In this study we aim to assess the diurnal cycle of rainfall across the Upper Blue Nile (UBN) basin using satellite observations from Tropical Rainfall Measuring Mission (TRMM). Seven years (2002-2008) of Precipitation Radar (PR) and TRMM Microwave Imager (TMI) data are used and analyses are based on GIS operations and simple statistical techniques. Observations from PR and TMI reveal that over most parts of the basin area, the rainfall occurrence and conditional mean rain rate are highest between mid- and late-afternoon (15:00-18:00 LST). Exceptions to this are the south-west and south-eastern parts of the basin area and the Lake Tana basin where midnight and early morning maxima are observed. Along the Blue Nile River gorge the rainfall occurrence and the conditional mean rain rate are highest during the night (20:00-23:00 LST). Orographic effects by large scale variation of topography, elevation and the presence of the UBN river gorge were assessed taking two transects across the basin. Along transects from north to south and from east to west results indicate increased rainfall with increase of elevation whereas areas on the windward side of the high mountain ranges receive higher amount of rainfall than areas on the leeward side. As such, mountain ranges and elevation affect the rainfall distribution resulting in rain shadow effect in the north-eastern parts of Choke-mountain and the ridges in the north-east of the basin. Moreover, a direct relation between rainfall occurrence and elevation is observed specifically for 17:00-18:00 LST. Further, results indicate that the rainfall distribution in the deeply incised and wide river gorge is affected with relatively low rainfall occurrence and low mean rainfall rates in the gorge areas. Seasonal mean rainfall depth is highest in the south-west area and central highlands of the basin while areas in the north, north-east and along the Blue Nile gorge receive the least amount of rainfall. Statistical results of this

  16. Water budget modelling of the Upper Blue Nile basin using the JGrass-NewAge model system and satellite data

    OpenAIRE

    Abera, Wuletawu; Formetta, Giuseppe; Brocca, Luca; Rigon, Riccardo

    2016-01-01

    The Upper Blue Nile basin is one of the most data-scarce regions in the world, hence, the hydrological information required for informed decision making in water resources management is limited. The hydrological complexity of the basin, tied with the lack of hydrometerological data, means that most hydrological studies in the region are either restricted to small subbasins where there are relatively better hydrometeorological data available, or at the whole basin scale but at v...

  17. Changes in land cover, rainfall and stream flow in Upper Gilgel Abbay catchment, Blue Nile basin – Ethiopia

    NARCIS (Netherlands)

    Rientjes, T.H.M.; Haile, A.T.; Kebede, E.; Mannaerts, C.M.M.; Habib, E.; Steenhuis, T.S.

    2011-01-01

    In this study we evaluated changes in land cover and rainfall in the Upper Gilgel Abbay catchment in the Upper Blue Nile basin and how changes affected stream flow in terms of annual flow, high flows and low flows. Land cover change assessment was through classification analysis of remote sensing ba

  18. Climate Change Impact on Variability of Rainfall Intensity in Upper Blue Nile Basin, Ethiopia

    Science.gov (United States)

    Worku, L. Y.

    2015-12-01

    Extreme rainfall events are major problems in Ethiopia with the resulting floods that usually could cause significant damage to agriculture, ecology, infrastructure, disruption to human activities, loss of property, loss of lives and disease outbreak. The aim of this study was to explore the likely changes of precipitation extreme changes due to future climate change. The study specifically focuses to understand the future climate change impact on variability of rainfall intensity-duration-frequency in Upper Blue Nile basin. Precipitations data from two Global Climate Models (GCMs) have been used in the study are HadCM3 and CGCM3. Rainfall frequency analysis was carried out to estimate quantile with different return periods. Probability Weighted Method (PWM) selected estimation of parameter distribution and L-Moment Ratio Diagrams (LMRDs) used to find the best parent distribution for each station. Therefore, parent distributions for derived from frequency analysis are Generalized Logistic (GLOG), Generalized Extreme Value (GEV), and Gamma & Pearson III (P3) parent distribution. After analyzing estimated quantile simple disaggregation model was applied in order to find sub daily rainfall data. Finally the disaggregated rainfall is fitted to find IDF curve and the result shows in most parts of the basin rainfall intensity expected to increase in the future. As a result of the two GCM outputs, the study indicates there will be likely increase of precipitation extremes over the Blue Nile basin due to the changing climate. This study should be interpreted with caution as the GCM model outputs in this part of the world have huge uncertainty.

  19. Characterisation of stable isotopes to identify residence times and runoff components in two meso-scale catchments in the Abay/Upper Blue Nile basin, Ethiopia

    NARCIS (Netherlands)

    Tekleab, S.; Wenninger, J.W.; Uhlenbrook, S.

    2014-01-01

    Measurements of the stable isotopes oxygen-18 (18O) and deuterium (2H) were carried out in two meso-scale catchments, Chemoga (358 km2) and Jedeb (296 km2) south of Lake Tana, Abay/Upper Blue Nile basin, Ethiopia. The region is of paramount importance for the water resources in the Nile basin, as mo

  20. Accuracy of satellite rainfall estimates in the Blue Nile Basin: Lowland plain versus highland mountain

    Science.gov (United States)

    Gebremichael, Mekonnen; Bitew, Menberu M.; Hirpa, Feyera A.; Tesfay, Gebrehiwot N.

    2014-11-01

    The demand for accurate satellite rainfall products is increasing particularly in Africa where ground-based data are mostly unavailable, timely inaccessible, and unreliable. In this study, the accuracy of three widely used, near-global, high-resolution satellite rainfall products (CMORPH, TMPA-RT v7, TMPA-RP v7), with a spatial resolution of 0.25° and a temporal resolution of 3 h, is assessed over the Blue Nile River Basin, a basin characterized by complex terrain and tropical monsoon. The assessment is made using relatively dense experimental networks of rain gauges deployed at two, 0.25° × 0.25°, sites that represent contrasting topographic features: lowland plain (mean elevation of 719 m.a.s.l.) and highland mountain (mean elevation of 2268 m.a.s.l.). The investigation period covers the summer seasons of 2012 and 2013. Compared to the highland mountain site, the lowland plain site exhibits marked extremes of rain intensity, higher mean rain intensity when it rains, lower frequency of rain occurrence, and smaller seasonal rainfall accumulation. All the satellite products considered tend to overestimate the mean rainfall rate at the lowland plain site, but underestimate it at the highland mountain site. The satellite products miss more rainfall at the highland mountain site than at the lowland plain site, and underestimate the heavy rain rates at both sites. Both sites have uncertainty (root mean square error) values greater than 100% for 3 h accumulations of mountain.

  1. Digging, Damming or Diverting? Small-Scale Irrigation in the Blue Nile Basin, Ethiopia

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    Irit Eguavoen

    2012-10-01

    Full Text Available The diversity of small-scale irrigation in the Ethiopian Blue Nile basin comprises small dams, wells, ponds and river diversion. The diversity of irrigation infrastructure is partly a consequence of the topographic heterogeneity of the Fogera plains. Despite similar social-political conditions and the same administrative framework, irrigation facilities are established, used and managed differently, ranging from informal arrangements of households and 'water fathers' to water user associations, as well as from open access to irrigation schedules. Fogera belongs to Ethiopian landscapes that will soon transform as a consequence of large dams and huge irrigation schemes. Property rights to land and water are negotiated among a variety of old and new actors. This study, based on ethnographic, hydrological and survey data, synthesises four case studies to analyse the current state of small-scale irrigation. It argues that all water storage options have not only certain comparative advantages but also social constraints, and supports a policy of extending water storage 'systems' that combine and build on complementarities of different storage types instead of fully replacing diversity by large dams.

  2. Social impact and impoverishment risks of the Koga irrigation scheme, Blue Nile basin, Ethiopia

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    Eguavoen, Irit

    2012-06-01

    Full Text Available The Koga project is the first new large-scale irrigation scheme in the Blue Nile river basin since the 1970s and may thus serve as an example of the tremendous changes of landscape and livelihood that are accompanying current water development projects in Ethiopia. This article analyzes the impoverishment risks arising out of the development-induced relocation of households in Koga. Following the Impoverishment Risk and Reconstruction model, seven of eight impoverishment risks could be identified, namely temporal landlessness, homelessness, joblessness, social marginalization, loss of household assets, social disarticulation and food insecurity, though the majority of relocated households succeeded in moving to other rural areas and did not face the challenges caused by urbanization. The Koga project and the local municipality undertook activities to reverse the impoverishment risk for the relocated households, but focused on the reconstruction of material livelihood assets (land, houses and compensation. The extent of rural-urban migration as a result of the project was underestimated. Proactive activities by the affected households succeeded in reducing their risk of impoverishment if they were informed early enough about the irrigation project.

  3. Morphological changes of Gumara River channel over 50 years, upper Blue Nile basin, Ethiopia

    Science.gov (United States)

    Abate, Mengiste; Nyssen, Jan; Steenhuis, Tammo S.; Moges, Michael M.; Tilahun, Seifu A.; Enku, Temesgen; Adgo, Enyew

    2015-06-01

    In response to anthropogenic disturbances, alluvial rivers adjust their geometry. The alluvial river channels in the upper Blue Nile basin have been disturbed by human-induced factors since a longtime. This paper examines channel adjustment along a 38-km stretch of the Gumara River which drains towards Lake Tana and then to the Blue Nile. Over a 50 years period, agriculture developed rapidly in the catchment and flooding of the alluvial plain has become more frequent in recent times. The objectives of this study were to document the changes in channel planform and cross-section of the Gumara River and to investigate whether the changes could have contributed to the frequent flooding or vice versa. Two sets of aerial photographs (1957 and 1980) were scanned, and then orthorectified. Recent channel planform information was extracted from SPOT images of 2006 and Google Earth. Channel planform and bed morphology (vertical changes) were determined for these nearly 50 years period. The vertical changes were determined based on aggradation along a permanent structure, historic information on river cross-sections at a hydrological gauging station, and field observations. The results indicate that the lower reach of Gumara near its mouth has undergone major planform changes. A delta with approx. 1.12 km2 of emerged land was created between 1957 and 1980 and an additional 1 km2 of land has been added between 1980 and 2006. The sinuosity of the river changed only slightly: negatively (-1.1% i.e. meandering decreased) for the period from 1957 to 1980 and positively (+3.0%) for the period 1980-2006. Comparison of cross-sections at the hydrological gauging station showed that the deepest point in the river bed aggraded by 2.91 m for the period 1963-2009. The importance of sediment deposition in the stream and on its banks is related to land degradation in the upper catchment, and to artificial rising of Lake Tana level that creates a backwater effect and sediment deposition in

  4. Analyzing catchment behavior through catchment modeling in the Gilgel Abay, Upper Blue Nile River Basin, Ethiopia

    Directory of Open Access Journals (Sweden)

    S. Uhlenbrook

    2010-10-01

    Full Text Available Understanding catchment hydrological processes is essential for water resources management, in particular in data scarce regions. The Gilgel Abay catchment (a major tributary into Lake Tana, source of the Blue Nile is undergoing intensive plans for water management, which is part of larger development plans in the Blue Nile basin in Ethiopia. To obtain a better understanding of the water balance dynamics and runoff generation mechanisms and to evaluate model transferability, catchment modeling has been conducted using the conceptual hydrological model HBV. Accordingly, the catchment of the Gilgel Abay has been divided into two gauged sub-catchments (Upper Gilgel Abay and Koga and the un-gauged part of the catchment. All available data sets were tested for stationarity, consistency and homogeneity and the data limitations (quality and quantity are discussed. Manual calibration of the daily models for three different catchment representations, i.e. (i lumped, (ii lumped with multiple vegetation zones, and (iii semi-distributed with multiple vegetation and elevation zones, showed good to satisfactory model performances with Nash-Sutcliffe efficiencies Reff > 0.75 and > 0.6 for the Upper Gilgel Abay and Koga sub-catchments, respectively. Better model results could not be obtained with manual calibration, very likely due to the limited data quality and model insufficiencies. Increasing the computation time step to 15 and 30 days improved the model performance in both sub-catchments to Reff > 0.8. Model parameter transferability tests have been conducted by interchanging parameters sets between the two gauged sub-catchments. Results showed poor performances for the daily models (0.30 < Reff < 0.67, but better performances for the 15 and 30 days models, Reff > 0.80. The transferability tests together with a sensitivity analysis using Monte Carlo simulations (more than 1 million

  5. Sediment concentration rating curves for a monsoonal climate: upper Blue Nile Basin

    Science.gov (United States)

    Moges, M. A.; Zemale, F. A.; Alemu, M. L.; Ayele, G. K.; Dagnew, D. C.; Tilahun, S. A.; Steenhuis, T. S.

    2015-12-01

    Information on sediment content in rivers is important for design of reservoirs and for environmental applications. Because of scarcity of continuous sediment data, methods have been developed to predict sediment loads based on few discontinuous measurements. Traditionally, loads are being predicted using rating curves that relate sediment load to discharge. The relationship assumes inherently a unique relationship between concentration and discharge and therefore although performing satisfactorily in predicting loads, it may be less suitable for predicting concentration. This is especially true in the Blue Nile basin of Ethiopia where concentrations decrease for a given discharge with the progression of the rainy monsoon phase. The objective of this paper is to improve the sediment concentration predictions throughout the monsoon period for the Ethiopian highlands with a modified rating type equation. To capture the observed sediment concentration pattern, we assume that the sediment concentration was at the transport limit early in the rainy season and then decrease linearly with effective rainfall towards source limited concentration. The modified concentration rating curve was calibrated for the four main rivers in the Lake Tana basin where sediment concentrations affect fish production and tourism. Then the scalability of the rating type equation was checked in three 100-ha watersheds for which historic data was available. The results show, that for predicting sediment concentrations, the (modified) concentration rating curve was more accurate than the (standard) load rating curve as expected. In addition loads were predicted more accurately for three of the four rivers. We expect that after more extensive testing over a wider geographical area, the proposed concentration rating curve will offer improved predictions of sediment concentrations in monsoonal climates.

  6. A participatory approach for hydrometeorological monitoring in the Blue Nile River Basin of Ethiopia

    OpenAIRE

    Zemadim, B.; McCartney, Matthew; Langan, Simon; Sharma, Bharat

    2013-01-01

    Participatory research is increasingly recognized as being useful for conducting multiple activities in research for development projects. The co-learning environment created in participatory research helps to identify existing social and technological gaps, and develop possible solutions to improve the livelihoods of rural communities. This report describes a participatory approach used in the establishment and implementation of hydrometeorological monitoring networks in the Blue Nile River ...

  7. Linking soil erosion to onsite financial cost: lessons from watersheds in the Blue Nile basin

    Directory of Open Access Journals (Sweden)

    T. Erkossa

    2015-02-01

    Full Text Available The study was conducted in three watersheds (Dapo, Meja and Mizewa in the Ethiopian part of the Blue Nile Basin to estimate the onsite cost of soil erosion using the productivity change approach, in which crop yield reduction due to plant nutrients lost with the sediment and runoff has been analyzed. For this purpose, runoff measurement and sampling was conducted during the main rainy season of 2011 at the outlet of two to three sub watersheds in each watershed. The sediment concentration of the runoff, and nitrogen and phosphorus content of the runoff and sediment were determined. Crop response functions were developed for the two plant nutrients based on data obtained from the nearest Agricultural Research Centers. The response functions were used to estimate crop yield reduction as a result of the lost N and P assuming there is no compensation through fertilization. The results show a significant yield reduction and resultant financial loss to the farmers. Considering only grain yield of maize (Zea mays, farmers at Dapo annually lose about 220 and USD 150 ha-1 due to the loss of nitrogen and phosphorus, respectively. In view of the importance of the crop residues including as feed, the loss can be even greater. The study demonstrated that in addition to the long-term deterioration of land quality, the annual financial loss suffered by farmers is substantial. Therefore, on farm soil and water conservation measures that are suitable in biophysical and socio-economic terms in the landscapes and beyond need to be encouraged.

  8. Hydrochemical evaluation of groundwater in the Blue Nile Basin, eastern Sudan, using conventional and multivariate techniques

    Science.gov (United States)

    Hussein, Mohammed Tahir

    Hydrochemical evaluation of groundwater systems can be carried out using conventional and multivariate techniques, namely cluster, factor analyses and others such as correspondence analysis. The main objective of this study is to investigate the groundwater quality in the Blue Nile basin of eastern Sudan, and to workout a hydrochemical evaluation for the aquifer system. Conventional methods and multivariate techniques were applied to achieve these goals. Two water-bearing layers exist in the study area: the Nubian Sandstone Formation and the Al-Atshan Formation. The Nubian aquifer is recharged mainly from the Blue Nile and Dinder Rivers through lateral subsurface flow and through direct rainfall in outcrop areas. The Al-Atshan aquifer receives water through underground flow from River Rahad and from rainfall infiltration. The prevailing hydrochemical processes are simple dissolution, mixing, partial ion exchange and ion exchange. Limited reverse ion exchange has been witnessed in the Nubian aquifer. Three factors control the overall mineralization and water quality of the Blue Nile Basin. The first factor includes high values of total dissolved solids, electrical conductivity, sodium, potassium, chloride, bicarbonate, sulphate and magnesium. The second factor includes calcium and pH. The third factor is due to fluoride concentration in the groundwater. The study highlights the descriptive capabilities of conventional and multivariate techniques as effective tools in groundwater quality evaluation. Une étude hydrochimique de systèmes aquifères a pu être réalisée au moyen des techniques conventionnelles et multidimensionnelles, telles que les analyses de cluster et factorielles, ainsi que d'autres comme l'analyse des correspondances. Le principal objectif de ce travail est d'étudier la qualité des eaux souterraines du bassin du Nil bleu au Soudan oriental, et de réaliser une évaluation hydrochimique du système aquifère. Des méthodes conventionnelles et

  9. Hydrological response to climate change for Gilgel Abay River, in the Lake Tana Basin -Upper Blue Nile Basin of Ethiopia.

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    Yihun Taddele Dile

    Full Text Available Climate change is likely to have severe effects on water availability in Ethiopia. The aim of the present study was to assess the impact of climate change on the Gilgel Abay River, Upper Blue Nile Basin. The Statistical Downscaling Tool (SDSM was used to downscale the HadCM3 (Hadley centre Climate Model 3 Global Circulation Model (GCM scenario data into finer scale resolution. The Soil and Water Assessment Tool (SWAT was set up, calibrated, and validated. SDSM downscaled climate outputs were used as an input to the SWAT model. The climate projection analysis was done by dividing the period 2010-2100 into three time windows with each 30 years of data. The period 1990-2001 was taken as the baseline period against which comparison was made. Results showed that annual mean precipitation may decrease in the first 30-year period but increase in the following two 30-year periods. The decrease in mean monthly precipitation may be as much as about -30% during 2010-2040 but the increase may be more than +30% in 2070-2100. The impact of climate change may cause a decrease in mean monthly flow volume between -40% to -50% during 2010-2040 but may increase by more than the double during 2070-2100. Climate change appears to have negligible effect on low flow conditions of the river. Seasonal mean flow volume, however, may increase by more than the double and +30% to +40% for the Belg (small rainy season and Kiremit (main rainy season periods, respectively. Overall, it appears that climate change will result in an annual increase in flow volume for the Gilgel Abay River. The increase in flow is likely to have considerable importance for local small scale irrigation activities. Moreover, it will help harnessing a significant amount of water for ongoing dam projects in the Gilgel Abay River Basin.

  10. Methods for interfacing IPCC climate change scenarios with higher resolution watershed management models in the Ethiopian Blue Nile Basin

    Science.gov (United States)

    Easton, Z. M.; MacAlister, C.; Fuka, D. R.

    2013-12-01

    As much as 90% of the Nile River flow that reaches Egypt originates in the Highlands of the Ethiopian Blue Nile Basin. This imbalance in water availability poses a threat to water security in the region, and could be severely impacted by projected climate change. This analysis coupled hydrodynamic/watershed models with the Intergovernmental Panel on Climate Change (IPCC) AR4 climate change scenarios to assess the potential impact on water resources and sediment dynamics. Specific AR4 scenarios include the A1B, B1, B2 and COMMIT, which were used to force the baseline hydrodynamic models calibrated against 1979-2011 streamflow for 20 sub-watersheds in the Tana and Beles basins. Transfer functions were developed to distribute the model parameters from the calibrated sub-watersheds to un-gauged portions of the basins based on a similarity index of hydrologic response units. We analyzed the scenario in two manners: first we ran all of the seven individual Global Circulation Model results in the IPCC AR4 report though our watershed models to asses the potential spread of climate change predictions; then we assessed the mean value produced for each IPCC AR4 scenario to better estimate convergence. Results indicate that the Tana basin is expected to experience an increase in mean annual flow. The Beles basin is predicted to experience a small decrease in mean annual flow. Sediment concentrations in the Tana basin increase proportionally more than the flow increase. Interestingly, and perhaps counter to what might be expected for a decrease in flow in the Beles basin, sediment concentrations increase.

  11. Comparative evaluation of different satellite rainfall estimation products and bias correction in the Upper Blue Nile (UBN) basin

    Science.gov (United States)

    Abera, Wuletawu; Brocca, Luca; Rigon, Riccardo

    2016-09-01

    In a region where ground-based gauge data are scarce, satellite rainfall estimates (SREs) are a viable option for proper space-time rainfall characterization. However, their accuracy and performances vary from region to region, and must be assessed. In this study, five high resolution satellite products (3B42V7, CMORPH, TAMSAT, SM2R-CCI, and CFSR) are compared and analyzed using the available rain gauge data in one of the most topographically and climatologically complex basin of Africa, the Upper Blue Nile basin (UBN). The basin rainfall is investigated systematically, and it is found that, at some locations, the difference in mean annual rainfall estimates between these SREs could be as much as about 2700 mm. Considering three goodness-of-fit indexes, correlation, bias and root mean square error (RMSE) between the SREs and ground-based gauge rainfall, CMORPH, TAMSAT and SM2R-CCI outperform the other two. Furthermore, a confusion matrix is used to investigate the detection ability of satellite rainfall products for different rainfall intensities. TAMSAT has the highest (91%) detection skill for dry days, followed by CFSR (77%). On the contrary, SM2R-CCI has the highest accuracy index for medium rainfall ranges (10-20 mm). The empirical cumulative distribution (ecdf) mapping technique is used to correct the intensities distribution givenby the SREs. This method provides a means to improve the rainfall estimation of all SREs, and the highest improvement is obtained for CMORPH (bias reduction from - 72% to - 1%).

  12. Water balance of a lake with floodplain buffering: Lake Tana, Blue Nile Basin, Ethiopia

    Science.gov (United States)

    Dessie, Mekete; Verhoest, Niko E. C.; Pauwels, Valentijn R. N.; Adgo, Enyew; Deckers, Jozef; Poesen, Jean; Nyssen, Jan

    2015-03-01

    Lakes are very important components of the earth's hydrological cycle, providing a variety of services for humans and ecosystem functioning. For a sustainable use of lakes, a substantial body of knowledge on their water balance is vital. We present here a detailed daily water balance analysis for Lake Tana, the largest lake in Ethiopia and the source of the Blue Nile. Rainfall on the lake is determined by Thiessen polygon procedure, open water evaporation is estimated by the Penman-combination equation and observed inflows for the gauged catchments as well as outflow data at the two lake outlets are directly used. Runoff from ungauged catchments is estimated using a simple rainfall-runoff model and runoff coefficients. Hillslope catchments and floodplains are treated separately, which makes this study unique compared to previous water balance studies. Impact of the floodplain on the lake water balance is analyzed by conducting scenario-based studies. We found an average yearly abstraction of 420 × 106 m3 or 6% of river inflows to the lake by the floodplain in 2012 and 2013. Nearly 60% of the inflow to the lake is from the Gilgel Abay River. Simulated lake levels compare well with the observed lake levels (R2 = 0.95) and the water balance can be closed with a closure error of 82 mm/year (3.5% of the total lake inflow). This study demonstrates the importance of floodplains and their influence on the water balance of the lake and the need of incorporating the effects of floodplains and water abstraction for irrigation to improve predictions.

  13. Catchment modeling and model transferability in upper Blue Nile Basin, Lake Tana, Ethiopia

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    A. S. Gragne

    2008-03-01

    Full Text Available Understanding spatial and temporal distribution of water resources has an important role for water resource management. To understand water balance dynamics and runoff generation mechanisms at the Gilgel Abay catchment (a major tributary into lake Tana, source of Blue Nile, Ethiopia and to evaluate model transferability, catchment modeling was conducted using the conceptual hydrological model HBV. The catchment of the Gigel Abay was sub-divided into two gauged sub-catchments (Upper Gilgel Abay, UGASC, and Koga, KSC and one ungauged sub-catchment.

    Manual calibration of the daily models for three different catchment representations (CRs: (i lumped, (ii lumped with multiple vegetation zones, and (iii semi-distributed with vegetations zone and elevation zones, showed good to satisfactory model performance (Nash-Sutcliffe efficiency values, Reff>0.75 and >0.6, respectively, for UGASC and KSC. The change of the time step to fifteen and thirty days resulted in very good model performances in both sub-catchments (Reff>0.8. The model parameter transferability tests conducted on the daily models showed poor performance in both sub-catchments, whereas the fifteen and thirty days models yielded high Reff values using transferred parameter sets. This together with the sensitivity analysis carried out after Monte Carlo simulations (1 000 000 model runs per CR explained the reason behind the difference in hydrologic behaviors of the two sub-catchments UGASC and KSC. The dissimilarity in response pattern of the sub-catchments was caused by the presence of dambos in KSC and differences in the topography between UGASC and KSC. Hence, transferring model parameters from the view of describing hydrological process was found to be not feasible for all models. On the other hand, from a water resources management perspective the results obtained by transferring parameters of the larger time step model were

  14. The use of remote sensing to quantify wetland loss in the Choke Mountain range, Upper Blue Nile basin, Ethiopia

    Directory of Open Access Journals (Sweden)

    E. Teferi

    2010-12-01

    Full Text Available Wetlands provide multiple ecosystem services such as storing and regulating water flows and water quality, providing unique habitats to flora and fauna, and regulating micro-climatic conditions. Conversion of wetlands for agricultural use is a widespread practice in Ethiopia, particularly in the southwestern part where wetlands cover large areas. Although there are many studies on land cover and land use changes in this region, comprehensive studies on wetlands are still missing. Hence, extent and rate of wetland loss at regional scales is unknown. The objective of this paper is to quantify wetland dynamics and estimate wetland loss in the Choke Mountain range (area covering 17 443 km2 in the Upper Blue Nile basin, a key headwater region of the river Nile. Therefore, satellite remote sensing imagery of the period 1986–2005 were considered. To create images of surface reflectance that are radiometrically consistent, a combination of cross-calibration and atmospheric correction (Vogelman-DOS3 methods was used. A hybrid supervised/unsupervised classification approach was used to classify the images. Overall accuracies of 94.1% and 93.5% and Kappa Coefficients of 0.908 and 0.913 for the 1986 and 2005 imageries, respectively were obtained. The results showed that 607 km2 of seasonal wetland with low moisture and 22.4 km2 of open water are lost in the study area during the period 1986 to 2005. The current situation in the wetlands of Choke Mountain is characterized by further degradation which calls for wetland conservation and rehabilitation efforts through incorporating wetlands into watershed management plans.

  15. The use of remote sensing to quantify wetland loss in the Choke Mountain range, Upper Blue Nile basin, Ethiopia

    Directory of Open Access Journals (Sweden)

    E. Teferi

    2010-08-01

    Full Text Available Wetlands provide multiple ecosystem services such as storing and regulating water flows and water quality, providing unique habitats to flora and fauna, and regulating micro-climatic conditions. Conversion of wetlands for agricultural use is a widespread practice in Ethiopia, particularly in the southwestern part where wetlands cover large areas. Although there are many studies on land cover and land use changes in this region, comprehensive studies on wetlands are still missing. Hence, extent and rate of wetland loss at regional scale is unknown. The objective of this paper is to quantify wetland dynamics and estimate wetland loss in the Choke Mountain range (area covering 17 443 km2 in the Upper Blue Nile basin, a key headwater region of the river Nile. Therefore, satellite remote sensing images of the period 1986–2005 were considered. To create images of surface reflectance that are radiometrically consistent, a combination of cross-calibration and atmospheric correction (Vogelman-DOS3 methods was used. A hybrid supervised/unsupervised classification approach was used to classify the images. Overall accuracies of 94.1% and 93.5% and Kappa Coefficients of 0.908 and 0.913 for the 1986 and 2005 imageries, respectively were obtained. The results showed that 607 km2 of seasonal wetland with low moisture and 22.4 km2 of open water are lost in the study area during the period 1986 to 2005. The current situation in the wetlands of Choke Mountain is characterized by further degradation which calls for wetland conservation and rehabilitation efforts through incorporating wetlands into watershed management plans.

  16. Changes in land cover and stream flows in Gilgel Abbay catchment, Upper Blue Nile basin – Ethiopia

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    T. H. M. Rientjes

    2010-12-01

    Full Text Available We evaluated the land cover change in the Upper Gilgel Abbay catchment in the Upper Blue Nile basin through classification analysis of remote sensing based land cover data and through assessing the changes in the hydrological regime by statistical analysis of stream flow observations. Results of the land cover classification analysis indicated that 50.9% and 16.7% of the catchment area was covered by forest in 1973 and 2001, respectively. This significant decrease in forest cover is mainly due to expansion of agricultural land. A comparison of stream flow time series of the Upper Gilgel Abbay catchment to stream flow time series from two neighbouring catchments shows a different trend and a statistically significant change over time. In 1986–2001, the annual and the high flows of the catchment increased by 13% and 46%, respectively while the low flows decreased by 35%. Generally, the results indicate significant changes in land cover and the hydrological regimes of the Upper Gilgel Abbay catchment over the past 30 years.

  17. Impact of Climate Change on Runoff in the Gilgel Abbay Watershed, the Upper Blue Nile Basin, Ethiopia

    Directory of Open Access Journals (Sweden)

    Hailu Sheferaw Ayele

    2016-09-01

    Full Text Available Hydrological assessment is critical to the successful implementation of adaption measures. In this study, projections of seven global circulation models (GCMs associated with high and medium–low Representative Concentration Pathways (RCP 8.5 and RCP 4.5 for the period 2021–2040 and 2081–2100 were adopted to assess changes on runoffs in the Gilgel Abbay watershed, the upper Blue Nile basin. A weather generator was employed to generate daily temperature and precipitation to drive a hydrological model for impact assessment. Despite the projected magnitude of changes varied among different GCMs and RCPs, increasing runoffs in wet-season and decreasing in dry-season are observed in both periods, mainly attributed to the change in projected precipitation. Such changes are profound in cases of RCP 8.5 with respect to those of RCP 4.5 and in cases of 2081–2100 with respect to those of 2021–2040. Although the increasing runoffs would provide greater inflow to Lake Tana, the increase of precipitation in wet-season would imply a higher possibility of flash floods. On the other hand, decrease runoffs in dry-season further intensify existing shortage of irrigation water demand. These changes will have deleterious consequences on the economic wellbeing of the country and require successful implementation of adaption measures to reduce vulnerability.

  18. Assessing Impact of Climate Change on the Runoffs of Gilgel Abbay Watershed, the upper Blue Nile Basin, Ethiopia

    Science.gov (United States)

    Ayele, H. S.; Li, M. H.; Tung, C. P.; Liu, T. M.

    2015-12-01

    Water is the most climate sensitive sector in changing climate. Hydrological vulnerability assessment is critical to the implementation of adaption measures. In this study, projections of 7 GCMs in association with high (RCP8.5) and medium low (RCP4.5) representative concentration path way from the CMPI5 (fifth phase of the Coupled Model Intercomparison Project) for the period 2021-2040 and 2081-2100 were adopted to assess the impacts of climate change on the runoffs of Gilgel Abbay watershed, the upper Blue Nile basin, in Ethiopia. The GCMs selected were first screened in harmony with baseline climate statistics of study areas. Based on climate projections and statistical characteristics of historical weather data, a weather generator was employed to generate daily temperature and precipitation as inputs for the GWLF hydrological model to simulate runoffs. Changes of projected temperature and precipitation were analyzed to explain variations of evapotranspiration and influences on future runoffs. We found that, despite the fact that the projected magnitude varies among different GCMs, increasing in the wet and a decreasing in dry seasons runoffs were observed in both time windows, which mainly attributes to the increase of precipitations projected by most of GCMs. In contrast to great increases in runoffs, the increase of evapotranspiration by elevating temperature is less significant. The increasing runoffs in both time windows will provide more water inflow to the Lake Tana. On the other hand, the increase of precipitation in wet season makes the wet season wetter and implies higher possibility of flash floods. This will have deleterious consequences in the local community. Therefore, concerned water organizations in local, state, and federal levels shall be prepared to harness the opportunities with more water resources for utilization and management, as well as flood preventive measures.

  19. Changes in land cover, rainfall and stream flow in Upper Gilgel Abbay catchment, Blue Nile basin – Ethiopia

    Directory of Open Access Journals (Sweden)

    T. H. M. Rientjes

    2011-06-01

    Full Text Available In this study we evaluated changes in land cover and rainfall in the Upper Gilgel Abbay catchment in the Upper Blue Nile basin and how changes affected stream flow in terms of annual flow, high flows and low flows. Land cover change assessment was through classification analysis of remote sensing based land cover data while assessments on rainfall and stream flow data are by statistical analysis. Results of the supervised land cover classification analysis indicated that 50.9 % and 16.7 % of the catchment area was covered by forest in 1973 and 2001, respectively. This significant decrease in forest cover is mainly due to expansion of agricultural land.

    By use of a change detection procedure, three periods were identified for which changes in rainfall and stream flow were analyzed. Rainfall was analyzed at monthly base by use of the Mann-Kendall test statistic and results indicated a statistically significant, decreasing trend for most months of the year. However, for the wet season months of June, July and August rainfall has increased. In the period 1973–2005, the annual flow of the catchment decreased by 12.1 %. Low flow and high flow at daily base were analyzed by a low flow and a high flow index that is based on a 95 % and 5 % exceedance probability. Results of the low flow index indicated decreases of 18.1 % and 66.6 % for the periods 1982–2000 and 2001–2005 respectively. Results of high flows indicated an increase of 7.6 % and 46.6 % for the same periods. In this study it is concluded that over the period 1973–2005 stream flow has changed in the Gilgel Abbay catchment by changes in land cover and changes in rainfall.

  20. Land-Use Change Modelling in the Upper Blue Nile Basin

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    Seleshi G. Yalew

    2016-08-01

    Full Text Available Land-use and land-cover changes are driving unprecedented changes in ecosystems and environmental processes at different scales. This study was aimed at identifying the potential land-use drivers in the Jedeb catchment of the Abbay basin by combining statistical analysis, field investigation and remote sensing. To do so, a land-use change model was calibrated and evaluated using the SITE (SImulation of Terrestrial Environment modelling framework. SITE is cellular automata based multi-criteria decision analysis framework for simulating land-use conversion based on socio-economic and environmental factors. Past land-use trajectories (1986–2009 were evaluated using a reference Landsat-derived map (agreement of 84%. Results show that major land-use change drivers in the study area were population, slope, livestock and distances from various infrastructures (roads, markets and water. It was also found that farmers seem to increasingly prefer plantations of trees such as Eucalyptus by replacing croplands perhaps mainly due to declining crop yield, soil fertility and climate variability. Potential future trajectory of land-use change was also predicted under a business-as-usual scenario (2009–2025. Results show that agricultural land will continue to expand from 69.5% in 2009 to 77.5% in 2025 in the catchment albeit at a declining rate when compared with the period from 1986 to 2009. Plantation forest will also increase at a much higher rate, mainly at the expense of natural vegetation, agricultural land and grasslands. This study provides critical information to land-use planners and policy makers for a more effective and proactive management in this highland catchment.

  1. Plan form changes of Gumara River channel over 50 years (Upper Blue Nile basin, Ethiopia)

    Science.gov (United States)

    Abate, Mengiste; Nyssen, Jan; Mehari, Michael

    2014-05-01

    Channel plan form changes were investigated along the 65 km long Gumara River in Lake Tana basin (Ethiopia) by overlaying information from aerial photographs and SPOT imagery. Two sets of aerial photographs (1957 and 1980) were scanned, and then orthorectified in ENVI 4.2 environment. Recent channel plan form information was extracted from SPOT images of 2006. ERDAS 2010 and ArcGIS 10.1 tools were used for the data preparation and analysis. The information on river plan form changes spans from 1957 to 2006 (49 years), during which time the Gumara catchment has been subjected to changes in land use/cover and increasing water abstraction, which may have affected its hydrogeomorphology. The results indicated that the lower reach of Gumara at its mouth has undergone major plan form changes. A delta of 1.12 km² was created between 1957 and 1980 and additional 1.00 km² land has been created between 1980 and 2006. The sinuosity of the plan form changed only slightly through the study period: 1.78 in 1957, 1.76 in 1980, and 1.81 in 2006. Comparison of cross sections at the hydrological gauging station showed that the river bed aggraded in the order of 1.5 m to 2.5 m for the period 1963-2009. The trend analysis of stream flow of Gumara River versus rainfall in the catchment also indicated that the bed level of the Gumara river at its gauging station has risen. From field observations, the impact of direct human interventions was identified. The building of artificial levees along the river banks has contributed to huge deposition in the river bed. At locations where intensive irrigation takes place in the floodplain, seepage water through the banks created river bank failure and modifications in plan form. The unstable segments of the river reach were identified and will be further analysed.

  2. Water balance modeling of Upper Blue Nile catchments using a top-down approach

    NARCIS (Netherlands)

    Tekleab, S.; Uhlenbrook, S.; Mohamed, Y.; Savenije, H.H.G.; Temesgen, M.; Wenninger, J.

    2011-01-01

    The water balances of twenty catchments in the Upper Blue Nile basin have been analyzed using a top-down modeling approach based on Budyko’s hypotheses. The objective of this study is to obtain better understanding of water balance dynamics of upper Blue Nile catchments on annual and monthly time sc

  3. Visualising DNA in Classrooms Using Nile Blue

    Science.gov (United States)

    Milne, Christine; Roche, Scott; McKay, David

    2008-01-01

    Giving students the opportunity to extract, manipulate and visualise DNA molecules enhances a constructivist approach to learning about modern techniques in biology and biotechnology Visualisation usually requires agarose gel electrophoresis and staining. In this article, we report on an alternative DNA stain, Nile Blue A, that may be used in the…

  4. Designing multi-reservoir system designs via efficient water-energy-food nexus trade-offs - Selecting new hydropower dams for the Blue Nile and Nepal's Koshi Basin

    Science.gov (United States)

    Harou, J. J.; Hurford, A.; Geressu, R. T.

    2015-12-01

    Many of the world's multi-reservoir water resource systems are being considered for further development of hydropower and irrigation aiming to meet economic, political and ecological goals. Complex river basins serve many needs so how should the different proposed groupings of reservoirs and their operations be evaluated? How should uncertainty about future supply and demand conditions be factored in? What reservoir designs can meet multiple goals and perform robustly in a context of global change? We propose an optimized multi-criteria screening approach to identify best performing designs, i.e., the selection, size and operating rules of new reservoirs within multi-reservoir systems in a context of deeply uncertain change. Reservoir release operating rules and storage sizes are optimized concurrently for each separate infrastructure design under consideration across many scenarios representing plausible future conditions. Outputs reveal system trade-offs using multi-dimensional scatter plots where each point represents an approximately Pareto-optimal design. The method is applied to proposed Blue Nile River reservoirs in Ethiopia, where trade-offs between capital costs, total and firm energy output, aggregate storage and downstream irrigation and energy provision for the best performing designs are evaluated. The impact of filling period for large reservoirs is considered in a context of hydrological uncertainty. The approach is also applied to the Koshi basin in Nepal where combinations of hydropower storage and run-of-river dams are being considered for investment. We show searching for investment portfolios that meet multiple objectives provides stakeholders with a rich view on the trade-offs inherent in the nexus and how different investment bundles perform differently under plausible futures. Both case-studies show how the proposed approach helps explore and understand the implications of investing in new dams in a global change context.

  5. Comparing TRMM 3B42, CFSR and ground-based rainfall estimates as input for hydrological models, in data scarce regions: the Upper Blue Nile Basin, Ethiopia

    Directory of Open Access Journals (Sweden)

    A. W. Worqlul

    2015-02-01

    Full Text Available Accurate prediction of hydrological models requires accurate spatial and temporal distribution of rainfall observation network. In developing countries rainfall observation station network are sparse and unevenly distributed. Satellite-based products have the potential to overcome these shortcomings. The objective of this study is to compare the advantages and the limitation of commonly used high-resolution satellite rainfall products as input to hydrological models as compared to sparsely populated network of rain gauges. For this comparison we use two semi-distributed hydrological models Hydrologiska Byråns Vattenbalansavdelning (HBV and Parameter Efficient Distributed (PED that performed well in Ethiopian highlands in two watersheds: the Gilgel Abay with relatively dense network and Main Beles with relatively scarce rain gauge stations. Both are located in the Upper Blue Nile Basin. The two models are calibrated with the observed discharge from 1994 to 2003 and validated from 2004 to 2006. Satellite rainfall estimates used includes Climate Forecast System Reanalysis (CFSR, Tropical Rainfall Measuring Mission (TRMM 3B42 version 7 and ground rainfall measurements. The results indicated that both the gauged and the CFSR precipitation estimates were able to reproduce the stream flow well for both models and both watershed. TRMM 3B42 performed poorly with Nash Sutcliffe values less than 0.1. As expected the HBV model performed slightly better than the PED model, because HBV divides the watershed into sub-basins resulting in a greater number of calibration parameters. The simulated discharge for the Gilgel Abay was better than for the less well endowed (rain gauge wise Main Beles. Finally surprisingly, the ground based gauge performed better for both watersheds (with the exception of extreme events than TRMM and CFSR satellite rainfall estimates. Undoubtedly in the future, when improved satellite products will become available, this will change.

  6. Effects of land use and land cover on selected soil quality indicators in the headwater area of the Blue Nile basin of Ethiopia.

    Science.gov (United States)

    Teferi, Ermias; Bewket, Woldeamlak; Simane, Belay

    2016-02-01

    Understanding changes in soil quality resulting from land use and land management changes is important to design sustainable land management plans or interventions. This study evaluated the influence of land use and land cover (LULC) on key soil quality indicators (SQIs) within a small watershed (Jedeb) in the Blue Nile Basin of Ethiopia. Factor analysis based on principal component analysis (PCA) was used to determine different SQIs. Surface (0-15 cm) soil samples with four replications were collected from five main LULC types in the watershed (i.e., natural woody vegetation, plantation forest, grassland, cultivated land, and barren land) and at two elevation classes (upland and midland), and 13 soil properties were measured for each replicate. A factorial (2 × 5) multivariate analysis of variance (MANOVA) showed that LULC and altitude together significantly affected organic matter (OM) levels. However, LULC alone significantly affected bulk density and altitude alone significantly affected bulk density, soil acidity, and silt content. Afforestation of barren land with eucalypt trees can significantly increase the soil OM in the midland part but not in the upland part. Soils under grassland had a significantly higher bulk density than did soils under natural woody vegetation indicating that de-vegetation and conversion to grassland could lead to soil compaction. Thus, the historical LULC change in the Jedeb watershed has resulted in the loss of soil OM and increased soil compaction. The study shows that a land use and management system can be monitored if it degrades or maintains or improves the soil using key soil quality indicators. PMID:26744135

  7. Effects of land use and land cover on selected soil quality indicators in the headwater area of the Blue Nile basin of Ethiopia.

    Science.gov (United States)

    Teferi, Ermias; Bewket, Woldeamlak; Simane, Belay

    2016-02-01

    Understanding changes in soil quality resulting from land use and land management changes is important to design sustainable land management plans or interventions. This study evaluated the influence of land use and land cover (LULC) on key soil quality indicators (SQIs) within a small watershed (Jedeb) in the Blue Nile Basin of Ethiopia. Factor analysis based on principal component analysis (PCA) was used to determine different SQIs. Surface (0-15 cm) soil samples with four replications were collected from five main LULC types in the watershed (i.e., natural woody vegetation, plantation forest, grassland, cultivated land, and barren land) and at two elevation classes (upland and midland), and 13 soil properties were measured for each replicate. A factorial (2 × 5) multivariate analysis of variance (MANOVA) showed that LULC and altitude together significantly affected organic matter (OM) levels. However, LULC alone significantly affected bulk density and altitude alone significantly affected bulk density, soil acidity, and silt content. Afforestation of barren land with eucalypt trees can significantly increase the soil OM in the midland part but not in the upland part. Soils under grassland had a significantly higher bulk density than did soils under natural woody vegetation indicating that de-vegetation and conversion to grassland could lead to soil compaction. Thus, the historical LULC change in the Jedeb watershed has resulted in the loss of soil OM and increased soil compaction. The study shows that a land use and management system can be monitored if it degrades or maintains or improves the soil using key soil quality indicators.

  8. Evaluation of climate anomalies impacts on the Upper Blue Nile Basin in Ethiopia using a distributed and a lumped hydrologic model

    Science.gov (United States)

    Elsanabary, Mohamed Helmy; Gan, Thian Yew

    2015-11-01

    Evaluating the climate anomalies impacts on the Upper Blue Nile Basin (UBNB), Ethiopia, a large basin with scarce hydroclimatic data, through hydrologic modeling is a challenge. A fully distributed, physically-based model, a modified version of the Interactions Soil-Biosphere Atmosphere model of Météo France (MISBA), and a lumped, conceptual rainfall-runoff Sacramento model, SAC-SMA of the US National Weather Service, were used to simulate the streamflow of UBNB. To study the potential hydrologic effect of climate anomalies on the UBNB, rainfall and temperature data observed when climate anomalies were active, were resampled and used to drive MISBA and SAC-SMA. To obtain representative, distributed precipitation data in mountainous basins, it was found that a 3% adjustment factor for every 25 m rise in elevation was needed to orographically correct the rainfall over UBNB. The performance of MISBA applied to UBNB improved after MISBA was modified so that it could simulate evaporation loss from the canopy, providing coefficient of determination (R2) = 0.58, and root mean square error (RMSE) = 0.34 m3/s in comparison with the observed streamflow. In contrast, the performance of SAC-SMA at the calibration run and the validation run is better than that of MISBA, such that R2 is 0.79 for calibration and 0.82 for validation even though it models the hydrology of UBNB in a lumped, conceptual framework as against the physically-based, fully distributed framework of MISBA. El Niño tends to decrease the June-September rainfall but increase the February-May rainfall, while La Niña has opposite effect on the rainfall of UBNB. Based on the simulations of MISBA and SAC-SMA for UBNB, La Niña and Indian Ocean Dipole (IOD) tend to have a wetting effect while El Niño has a drying effect on the streamflow of the UBNB. In addition, El Niño Southern Oscillation (ENSO) and IOD increase the streamflow variability more than changing the magnitude of streamflow. The results provide

  9. Nile Blue derivatives as lysosomotropic photosensitizers

    Science.gov (United States)

    Lin, Chi-Wei; Shulok, Janine R.; Kirley, S. D.; Cincotta, Louis; Foley, James W.

    1991-06-01

    The benzophenoxazines, including several Nile blue analogues, are a unique group of dyes that localize selectively in animal tumors. Chemical modifications of Nile blue A can yield derivatives with high 1O2 quantum yields. These derivatives represent a group of potentially effective photosensitizers for selective phototherapy of malignant tumors. In vitro evaluation of these derivatives has indicated that those with high 1O2 yields are very effective in mediating the photocytotoxicity of tumor cells. This photodynamic effect is most likely mediated through the action of 1O2, since photoirradiation under D2O enhanced and under hypoxic conditions diminished the photocytotoxic action. The subcellular localization of these photosensitizers in bladder tumor cells in culture was examined by light and fluorescence microscopies as well as by histochemical and biochemical studies. The results indicate that these dyes are localized primarily in the lysosome. The cellular uptake and retention of these dyes is energy- and pH-dependent. Agents such as nigericin, which alter the transmembrane pH gradient, reduced uptake and enhanced efflux of the dyes, while agents such as valinomycin, which reduce cellular membrane potential, had no effect on the uptake. These findings are consistent with having ion-trapping as the mechanism for the uptake of these dyes. Photoirradiation of sensitizer-treated cells obliterated lysosomes in a light-dose and drug-dose dependent fashion. Release of the hydrolytic enzymes may be the main cause for subsequent cell death since the cytolytic effect was reduced by a specific inhibitor of lysosomal proteolytic enzyme. A lysosomotropic photosensitization mechanism is therefore proposed for the photocytotoxic action of the Nile blue derivatives. This mechanism may provide an approach to the development of new photosensitizers for the effective and selective destruction of malignant tumors.

  10. Late Pleistocene and Holocene environments in the Nile basin

    Science.gov (United States)

    Williams, Martin A. J.

    2009-10-01

    Owing to the very gently sloping nature of the flood plain in the lower White Nile valley, which is underlain by a former lake-bed, the depositional record in that area is unusually well preserved. In Egypt and along the Blue Nile phases of erosion have destroyed segments of the sedimentary record, but the White Nile sequence is a good proxy for both the main Nile and the Blue Nile. During the last 15 ka, at least, times of high flow in the Blue Nile and main Nile were synchronous with those in the White Nile. Not all the White Nile flood deposits have been preserved but calibrated radiocarbon dates obtained on fossil freshwater and amphibious Pila shells and fish bones indicate that White Nile levels were high around 14.7-13.1 ka, 9.7-9.0 ka, 7.9-7.6 ka, 6.3 ka and 3.2-2.8 ka. The Blue Nile record is more fragmentary and that of the main Nile even more so except for the Holocene Nile delta. Calibrated radiocarbon ages for high Blue Nile flows indicate very high flood levels towards 13.9-13.2 ka, 8.6 ka, 7.7 ka and 6.3 ka. Incision by the Blue Nile and main Nile has caused progressive incision in the White Nile amounting to at least 4 m since the terminal Pleistocene ˜ 15 ka ago and at least 2 m over the past 9 ka. The Blue Nile seems to have cut down at least 10 m since ˜ 15 ka and at least 4 m since 9 ka. The time-transgressive and relatively late inception of plant domestication in the Nile valley may partly reflect this history of incision. Nile incision would propagate upstream into the White Nile valley, draining previously swampy areas along the valley floor, which would then become accessible to cultivation.

  11. Identifying residence times and streamflow generation processes using δ18O and δ2H in meso-scale catchments in the Abay/Upper Blue Nile, Ethiopia

    NARCIS (Netherlands)

    Teklaeb, S.; Wenninger, J.W.; Uhlenbrook, S.

    2013-01-01

    Measurements of the stable isotopes oxygen-18 (18O) and deuterium (2H) were carried out in two meso-scale catchments, Chemoga (358 km2) and Jedeb (296 km2) south of Lake Tana, Abay/Upper Blue Nile basin, Ethiopia. The region is of paramount importance for the water resources in the Nile basin. Stabl

  12. Impacts of climate change on Blue Nile flows using bias-corrected GCM scenarios

    Directory of Open Access Journals (Sweden)

    M. E. Elshamy

    2009-05-01

    Full Text Available This study analyses the output of 17 general circulation models (GCMs included in the 4th IPCC assessment report. Downscaled precipitation and potential (reference crop evapotranspiration (PET scenarios for the 2081–2098 period were constructed for the upper Blue Nile basin. These were used to drive a fine-scale hydrological model of the Nile Basin to assess their impacts on the flows of the upper Blue Nile at Diem, which accounts for about 60% of the mean annual discharge of the Nile at Dongola. There is no consensus among the GCMs on the direction of precipitation change. Changes in total annual precipitation range between −15% to +14% but more models report reductions (10 than those reporting increases (7. Several models (6 report small changes within 5%. The ensemble mean of all models shows almost no change in the annual total rainfall. All models predict the temperature to increase between 2°C and 5°C and consequently PET to increase by 2–14%. Changes to the water balance are assessed using the Budyko framework. The basin is shown to belong to a moisture constrained regime. However, during the wet season the basin is largely energy constrained. For no change in rainfall, increasing PET thus leads to a reduced wet season runoff coefficient. The ensemble mean runoff coefficient (about 20% for baseline simulations is reduced by about 3.5%. Assuming no change or moderate changes in rainfall, the simulations presented here indicate that the water balance of the upper Blue Nile basin may become more moisture constrained in the future.

  13. Hydroclimate variability in the Nile River Basin during the past 28,000 years

    Science.gov (United States)

    Castañeda, Isla S.; Schouten, Stefan; Pätzold, Jürgen; Lucassen, Friedrich; Kasemann, Simone; Kuhlmann, Holger; Schefuß, Enno

    2016-03-01

    It has long been known that extreme changes in North African hydroclimate occurred during the late Pleistocene yet many discrepancies exist between sites regarding the timing, duration and abruptness of events such as Heinrich Stadial (HS) 1 and the African Humid Period (AHP). The hydroclimate history of the Nile River is of particular interest due to its lengthy human occupation history yet there are presently few continuous archives from the Nile River corridor, and pre-Holocene studies are rare. Here we present new organic and inorganic geochemical records of Nile Basin hydroclimate from an eastern Mediterranean (EM) Sea sediment core spanning the past 28 ka BP. Our multi-proxy records reflect the fluctuating inputs of Blue Nile versus White Nile material to the EM Sea in response to gradual changes in local insolation and also capture abrupt hydroclimate events driven by remote climate forcings, such as HS1. We find strong evidence for extreme aridity within the Nile Basin evolving in two distinct phases during HS1, from 17.5 to 16 ka BP and from 16 to 14.5 ka BP, whereas peak wet conditions during the AHP are observed from 9 to 7 ka BP. We find that zonal movements of the Congo Air Boundary (CAB), and associated shifts in the dominant moisture source (Atlantic versus Indian Ocean moisture) to the Nile Basin, likely contributed to abrupt hydroclimate variability in northern East Africa during HS1 and the AHP as well as to non-linear behavior of hydroclimate proxies. We note that different proxies show variable gradual and abrupt responses to individual hydroclimate events, and thus might have different inherent sensitivities, which may be a factor contributing to the controversy surrounding the abruptness of past events such as the AHP. During the Late Pleistocene the Nile Basin experienced extreme hydroclimate fluctuations, which presumably impacted Paleolithic cultures residing along the Nile corridor.

  14. Water balance modeling of Upper Blue Nile catchments using a top-down approach

    Directory of Open Access Journals (Sweden)

    S. Tekleab

    2010-09-01

    Full Text Available The hydrological behavior and functioning of twenty catchments in the Upper Blue Nile basin have been analyzed using a top-down modeling approach that is based on Budyko's hypotheses. The objective is to obtain better understanding of catchment response for prediction in ungauged catchments. The water balance analysis using Budyko-type curve at annual scale reveals that the aridity index does not exert a first order control in most of the catchments. This implies the need to increase model complexity to a monthly time scale to include the effects of seasonal soil moisture dynamics. The dynamic water balance model used in this study predicts the direct runoff and other processes based on limit concept. The uncertainty of model parameters has been assessed using the GLUE (Generalized Likelihood Uncertainty Estimation. The results show that the majority of the parameters are reasonably well identifiable. Moreover, a multi-objective model calibration strategy has been employed within the GLUE framework to emphasize the different aspects of the hydrographs on low and high flows. The model has been calibrated and validated against observed streamflow time series and it shows good performance for the twenty catchments of the upper Blue Nile. During the calibration period (1995–2000 the Nash and Sutcliffe coefficient of efficiency for monthly flow prediction varied between 0.52 to 0.93 during high flows, while it varied between 0.32 to 0.90 during low flows (logarithms of flow series. The model is parsimonious and it is suggested that the resulting parameters can be used to predict monthly stream flows in the ungauged catchments of the Upper Blue Nile basin, which accounts about 60% of total Nile basin flow.

  15. Mutually beneficial and sustainable management of Ethiopian and Egyptian dams in the Nile Basin

    Science.gov (United States)

    Habteyes, Befekadu G.; Hasseen El-bardisy, Harb A. E.; Amer, Saud A.; Schneider, Verne R.; Ward, Frank A.

    2015-10-01

    Ongoing pressures from population growth, recurrent drought, climate, urbanization and industrialization in the Nile Basin raise the importance of finding viable measures to adapt to these stresses. Four tributaries of the Eastern Nile Basin contribute to supplies: the Blue Nile (56%), White Nile-Albert (14%), Atbara (15%) and Sobat (15%). Despite much peer reviewed work addressing conflicts on the Nile, none to date has quantitatively examined opportunities for discovering benefit sharing measures that could protect negative impacts on downstream water users resulting from new upstream water storage developments. The contribution of this paper is to examine the potential for mutually beneficial and sustainable benefit sharing measures from the development and operation of the Grand Ethiopian Renaissance Dam while protecting baseline flows to the downstream countries including flows into the Egyptian High Aswan Dam. An integrated approach is formulated to bring the hydrology, economics and institutions of the region into a unified framework for policy analysis. A dynamic optimization model is developed and applied to identify the opportunities for Pareto Improving measures to operate these two dams for the four Eastern Nile Basin countries: Ethiopia, South Sudan, Sudan, and Egypt. Results indicate a possibility for one country to be better off (Ethiopia) and no country to be worse off from a managed operation of these two storage facilities. Still, despite the optimism of our results, considerable diplomatic negotiation among the four riparians will be required to turn potential gains into actual welfare improvements.

  16. Groundwater recharge, circulation and geochemical evolution in the source region of the Blue Nile River, Ethiopia

    Energy Technology Data Exchange (ETDEWEB)

    Kebede, Seifu [Laboratory of Hydrogeology, University of Avignon, 33 Rue Louis Pasteur, 84000 Avignon (France) and Department of Geology and Geophysics, Addis Ababa University, P.O. Box 1176, Addis Ababa (Ethiopia)]. E-mail: seifu.kebede@univ-avignon.fr; Travi, Yves [Laboratory of Hydrogeology, University of Avignon, 33 Rue Louis Pasteur, 84000 Avignon (France); Alemayehu, Tamiru [Department of Geology and Geophysics, Addis Ababa University, P.O. Box 1176, Addis Ababa (Ethiopia); Ayenew, Tenalem [Department of Geology and Geophysics, Addis Ababa University, P.O. Box 1176, Addis Ababa (Ethiopia)

    2005-09-15

    Geochemical and environmental isotope data were used to gain the first regional picture of groundwater recharge, circulation and its hydrochemical evolution in the upper Blue Nile River basin of Ethiopia. Q-mode statistical cluster analysis (HCA) was used to classify water into objective groups and to conduct inverse geochemical modeling among the groups. Two major structurally deformed regions with distinct groundwater circulation and evolution history were identified. These are the Lake Tana Graben (LTG) and the Yerer Tullu Wellel Volcanic Lineament Zone (YTVL). Silicate hydrolysis accompanied by CO{sub 2} influx from deeper sources plays a major role in groundwater chemical evolution of the high TDS Na-HCO {sub 3} type thermal groundwaters of these two regions. In the basaltic plateau outside these two zones, groundwater recharge takes place rapidly through fractured basalts, groundwater flow paths are short and they are characterized by low TDS and are Ca-Mg-HCO {sub 3} type waters. Despite the high altitude (mean altitude {approx}2500 masl) and the relatively low mean annual air temperature (18 deg. C) of the region compared to Sahelian Africa, there is no commensurate depletion in {delta} {sup 18}O compositions of groundwaters of the Ethiopian Plateau. Generally the highland areas north and east of the basin are characterized by relatively depleted {delta} {sup 18}O groundwaters. Altitudinal depletion of {delta} {sup 18}O is 0.1%o/100 m. The meteoric waters of the Blue Nile River basin have higher d-excess compared to the meteoric waters of the Ethiopian Rift and that of its White Nile sister basin which emerges from the equatorial lakes region. The geochemically evolved groundwaters of the YTVL and LTG are relatively isotopically depleted when compared to the present day meteoric waters reflecting recharge under colder climate and their high altitude.

  17. Groundwater recharge, circulation and geochemical evolution in the source region of the Blue Nile River, Ethiopia

    International Nuclear Information System (INIS)

    Geochemical and environmental isotope data were used to gain the first regional picture of groundwater recharge, circulation and its hydrochemical evolution in the upper Blue Nile River basin of Ethiopia. Q-mode statistical cluster analysis (HCA) was used to classify water into objective groups and to conduct inverse geochemical modeling among the groups. Two major structurally deformed regions with distinct groundwater circulation and evolution history were identified. These are the Lake Tana Graben (LTG) and the Yerer Tullu Wellel Volcanic Lineament Zone (YTVL). Silicate hydrolysis accompanied by CO2 influx from deeper sources plays a major role in groundwater chemical evolution of the high TDS Na-HCO 3 type thermal groundwaters of these two regions. In the basaltic plateau outside these two zones, groundwater recharge takes place rapidly through fractured basalts, groundwater flow paths are short and they are characterized by low TDS and are Ca-Mg-HCO 3 type waters. Despite the high altitude (mean altitude ∼2500 masl) and the relatively low mean annual air temperature (18 deg. C) of the region compared to Sahelian Africa, there is no commensurate depletion in δ 18O compositions of groundwaters of the Ethiopian Plateau. Generally the highland areas north and east of the basin are characterized by relatively depleted δ 18O groundwaters. Altitudinal depletion of δ 18O is 0.1%o/100 m. The meteoric waters of the Blue Nile River basin have higher d-excess compared to the meteoric waters of the Ethiopian Rift and that of its White Nile sister basin which emerges from the equatorial lakes region. The geochemically evolved groundwaters of the YTVL and LTG are relatively isotopically depleted when compared to the present day meteoric waters reflecting recharge under colder climate and their high altitude

  18. Late Pleistocene desiccation of Lake Tana, source of the Blue Nile

    Science.gov (United States)

    Lamb, Henry F.; Bates, C. Richard; Coombes, Paul V.; Marshall, Michael H.; Umer, Mohammed; Davies, Sarah J.; Dejen, Eshete

    2007-02-01

    High-resolution seismic data from Lake Tana, the source of the Blue Nile in northern Ethiopia, reveal a deep sedimentary sequence divided by four strong reflectors. Data from nearshore cores show that the uppermost strong reflector represents a stiff silt unit, interpreted as a desiccation surface. Channel cuts in this surface, bordered by levee-like structures, are apparent in the seismic data from near the lake margin, suggesting fluvial downcutting and over-bank deposition during seasonal flood events. Periphytic diatoms and peat at the base of a core from the deepest part of the lake overlie compacted sediments, indicating that desiccation was followed by development of shallow-water environments and papyrus swamp in the central basin between 16,700 and 15,100 cal BP. As the lake level rose, open-water evaporation from the closed lake caused it to become slightly saline, as indicated by halophytic diatoms. An abrupt return to freshwater conditions occurred at 14,750 cal BP, when the lake overflowed into the Blue Nile. Further reflection surfaces with downcut structures are identifiable in seismic images of the overlying sediments, suggesting at least two lesser lake-level falls, tentatively dated to about 12,000 and 8000 cal BP. Since Lake Victoria, the source of the White Nile, was also dry until 15,000 cal BP, and did not reach overflow until 14,500 cal BP, the entire Nile system must have been reduced to intermittent seasonal flow until about 14,500 cal BP, when baseflow was re-established with almost simultaneous overflow of the headwater lakes of both the White and Blue Nile rivers. Desiccation of the Nile sources coincides with Heinrich event 1, when cessation of northward heat transport from the tropical Atlantic disrupted the Atlantic monsoon, causing drought in north tropical Africa. The strong reflectors at deeper levels in the seismic sequence of Lake Tana may represent earlier desiccation events, possibly contemporaneous with previous Late

  19. Water balance modeling of Upper Blue Nile catchments using a top-down approach

    Directory of Open Access Journals (Sweden)

    S. Tekleab

    2011-07-01

    Full Text Available The water balances of twenty catchments in the Upper Blue Nile basin have been analyzed using a top-down modeling approach based on Budyko's hypotheses. The objective of this study is to obtain better understanding of water balance dynamics of upper Blue Nile catchments on annual and monthly time scales and on a spatial scale of meso scale to large scale. The water balance analysis using a Budyko-type curve at annual scale reveals that the aridity index does not exert a first order control in most of the catchments. This implies the need to increase model complexity to monthly time scale to include the effects of seasonal soil moisture dynamics. The dynamic water balance model used in this study predicts the direct runoff and other processes based on the limit concept; i.e. for dry environments since rainfall amount is small, the aridity index approaches to infinity or equivalently evaporation approaches rainfall and for wet environments where the rainfall amount is large, the aridity index approaches to zero and actual evaporation approaches the potential evaporation. The uncertainty of model parameters has been assessed using the GLUE (Generalized Likelihood Uncertainty Estimation methodology. The results show that the majority of the parameters are reasonably well identifiable. However, the baseflow recession constant was poorly identifiable. Parameter uncertainty and model structural errors could be the reason for the poorly identifiable parameter. Moreover, a multi-objective model calibration strategy has been employed to emphasize the different aspects of the hydrographs on low and high flows.

    The model has been calibrated and validated against observed streamflow time series and it shows good performance for the twenty study catchments in the upper Blue Nile. During the calibration period (1995–2000 the Nash and Sutcliffe efficiency (E NS for monthly flow prediction varied between 0.52 to 0.93 (dominated by

  20. Drought in the Nile Basin: characterizing variability, quantifying uncertainty, and studying processes with the Nile Land Data Assimilation System

    Science.gov (United States)

    Alo, C. A.; Zaitchik, B. F.; Habib, S.; Anderson, M. C.; Ozdogan, M.

    2010-12-01

    The Nile Land Data Assimilation System (Nile LDAS) has been developed to support studies of hydrologic variability, land cover patterns, and climate change impacts in the countries that share the Nile basin. Here we present results of retrospective Nile LDAS simulations that examine climatic and hydrologic variability across the basin in recent decades. Use of Nile LDAS in this study allows us to compare patterns of drought as captured by different precipitation datasets—including Tropical Rainfall Measurement Mission (TRMM) precipitation products, the CPC Merged Analysis of Precipitation (CMAP), and multiple meteorological reanalyses—different land surface models—including Noah Land Surface Model, the Common Land Model, and Catchment LSM—and independent satellite observations—including the Gravity Recovery and Climate Experiment (GRACE). Results of Nile LDAS simulations show distinct temporal and spatial patterns of drought across the climatic gradients of the Nile basin. These results also demonstrate that diagnosis of drought patterns is sensitive to choice of meteorological dataset and land surface model. We present an objective classification of drought susceptibility zones based on the results of these Nile LDAS simulations, including assessment of confidence and uncertainty. Lastly, we discuss the possible drivers of hydrological variability at the local to the basin scale. Follow-on studies are in progress to merge, compare, and improve Nile LDAS datasets in order to provide optimal estimates of hydrological states and fluxes in the Nile basin, with the ultimate objective of improving drought analysis and response in an evolving climate.

  1. The question of Sudan: a hydro-economic optimization model for the Sudanese Blue Nile

    Science.gov (United States)

    Satti, S.; Zaitchik, B.; Siddiqui, S.

    2015-05-01

    The effects of development and the uncertainty of a changing climate in eastern Africa pose myriad challenges for water managers along the Blue Nile. Sudan's large irrigation potential, hydroelectric dams, and prime location within the basin mean that Sudan's water management decisions will have great social, economic and political implications for the region. At the same time, Sudan's water use options are constrained by tradeoffs between upstream irrigation developments and downstream hydropower facilities as well as by the country's commitments under existing or future transboundary water sharing agreements. Here, we present a model that can be applied to evaluate optimal allocation of surface water resources to irrigation and hydropower in the Sudanese portion of the Blue Nile. Hydrologic inputs are combined with agronomic and economic inputs to formulate an optimization model within the General Algebraic Modeling System (GAMS). A sensitivity analysis is performed by testing model response to a range of economic conditions and to changes in the volume and timing of hydrologic flows. Results indicate that changing hydroclimate inputs have the capacity to greatly influence the productivity of Sudan's water resource infrastructure. Results also show that the economically optimal volume of water consumption, and thus the importance of existing treaty constraints, is sensitive to the perceived value of agriculture relative to electricity as well as to changing hydrological conditions.

  2. Identifying residence times and streamflow generation processes using δ18O and δ2H in meso-scale catchments in the Abay/Upper Blue Nile, Ethiopia

    OpenAIRE

    Teklaeb, S.; Wenninger, J.W.; Uhlenbrook, S.

    2013-01-01

    Measurements of the stable isotopes oxygen-18 (18O) and deuterium (2H) were carried out in two meso-scale catchments, Chemoga (358 km2) and Jedeb (296 km2) south of Lake Tana, Abay/Upper Blue Nile basin, Ethiopia. The region is of paramount importance for the water resources in the Nile basin. Stable isotope composition in precipitation, spring water and streamflow were analyzed (i) to characterize the spatial and temporal variations of water fluxes; (ii) to estimate the mean residence time o...

  3. Agricultural Model for the Nile Basin Decision Support System

    Science.gov (United States)

    van der Bolt, Frank; Seid, Abdulkarim

    2014-05-01

    To analyze options for increasing food supply in the Nile basin the Nile Agricultural Model (AM) was developed. The AM includes state-of-the-art descriptions of biophysical, hydrological and economic processes and realizes a coherent and consistent integration of hydrology, agronomy and economics. The AM covers both the agro-ecological domain (water, crop productivity) and the economic domain (food supply, demand, and trade) and allows to evaluate the macro-economic and hydrological impacts of scenarios for agricultural development. Starting with the hydrological information from the NileBasin-DSS the AM calculates the available water for agriculture, the crop production and irrigation requirements with the FAO-model AquaCrop. With the global commodity trade model MAGNET scenarios for land development and conversion are evaluated. The AM predicts consequences for trade, food security and development based on soil and water availability, crop allocation, food demand and food policy. The model will be used as a decision support tool to contribute to more productive and sustainable agriculture in individual Nile countries and the whole region.

  4. Nile tilapia and blue tilapia fry production in a subtropical climate

    Science.gov (United States)

    The relationship between production in earthen ponds located in a subtropical climate of fry suitable for hormonal sex inversion and degree-days was quantified for Nile tilapia (Oreochromis niloticus; Egypt strain) and blue tilapia (O. aureus). Degree-days were calculated for each trial as the sum o...

  5. Causal links between Nile floods and eastern Mediterranean sapropel formation during the past 125 kyr confirmed by OSL and radiocarbon dating of Blue and White Nile sediments

    Science.gov (United States)

    Williams, M. A. J.; Duller, G. A. T.; Williams, F. M.; Woodward, J. C.; Macklin, M. G.; El Tom, O. A. M.; Munro, R. N.; El Hajaz, Y.; Barrows, T. T.

    2015-12-01

    It has long been hypothesised that beds of highly organic mud or sapropels seen in marine sediment cores retrieved from the floor of the eastern Mediterranean accumulated during times of high Nile fluvial discharge. Our recent fieldwork in the valleys of the Blue Nile, the White Nile and the main Nile has for the first time revealed a sequence of extreme flood episodes synchronous with sapropel units S5 (124 kyr), S4 (102 kyr), S3 (81 kyr), S2 (55 kyr) and S1 (13.5-6.5 kyr). There are more weakly defined links with Nile floods and sapropel units S9 (240 kyr), S8 (217 kyr), S7 (195 kyr), S6 (172 kyr), but the dating error terms are too large to allow us to be too definite. During times of extreme floods over the past 125 kyr, wide distributary channels of the Blue Nile flowed across the Gezira alluvial fan in central Sudan and transported a bed load of sand and gravel into the lower White Nile valley. The sands were reworked by wind to form source-bordering dunes, all of which contain heavy minerals of Ethiopian provenance. These source-bordering dunes were active at 115-105 kyr, 60 kyr and 12-7 kyr, all times of extreme Blue Nile floods. The flood and dune sediments were dated using a combination of optically stimulated luminescence (OSL) and radiocarbon analyses. The Quaternary record of Nile floods discussed here shows a precessional signal and reflects episodes of stronger summer monsoon and more northerly seasonal movement of the ITCZ, linked to times of higher insolation in northern tropical latitudes. Progressive aggradation of Holocene Nile channels in northern Sudan has had a profound influence upon human settlement in the last 8 kyr.

  6. Incentive compatibility and conflict resolution in international river basins: A case study of the Nile Basin

    Science.gov (United States)

    Wu, Xun; Whittington, Dale

    2006-02-01

    Nation-states rarely go to war over water, but it is equally rare that water conflicts in an international river basin are resolved through cooperation among the riparian countries that use the shared resources. Gains from cooperation will mean little to individual riparians unless the required cooperative behaviors are incentive compatible. Cooperative game theory offers useful insights for assessing cooperative solutions for water conflicts in international river basins. Applying cooperative game theory concepts such as core, nucleolus, and Shapley value to Nile water conflicts, we examine the incentive structure of both cooperative and noncooperative strategies for different riparian countries and establish some baseline conditions for incentive-compatible cooperation in the Nile basin.

  7. Sediment concentration rating curves for a monsoonal climate: upper Blue Nile

    Science.gov (United States)

    Moges, Mamaru A.; Zemale, Fasikaw A.; Alemu, Muluken L.; Ayele, Getaneh K.; Dagnew, Dessalegn C.; Tilahun, Seifu A.; Steenhuis, Tammo S.

    2016-07-01

    Information on sediment concentration in rivers is important for design of reservoirs and for environmental applications. Because of the scarcity of continuous sediment data, methods have been developed to predict sediment loads based on few discontinuous measurements. Traditionally, loads are being predicted using rating curves that relate sediment load to discharge. The relationship assumes inherently a unique relationship between concentration and discharge and therefore although performing satisfactorily in predicting loads, it may be less suitable for predicting concentration. This is especially true in the Blue Nile Basin of Ethiopia where concentrations decrease for a given discharge with the progression of the rainy monsoon phase. The objective of this paper is to improve the sediment concentration predictions throughout the monsoon period for the Ethiopian highlands with a modified rating type equation. To capture the observed sediment concentration pattern, we assume that the sediment concentration was at the transport limit early in the rainy season and then decreases linearly with effective rainfall towards source-limited concentration. The modified concentration rating curve was calibrated for the four main rivers in the Lake Tana basin where sediment concentrations affect fish production and tourism. Then the scalability of the rating type equation was checked in three 100 ha watersheds for which historic data were available. The results show that for predicting sediment concentrations, the (modified) concentration rating curve was more accurate than the (standard) load rating curve as expected. In addition loads were predicted more accurately for three of the four rivers. We expect that after more extensive testing over a wider geographical area, the proposed concentration rating curve will offer improved predictions of sediment concentrations in monsoonal climates.

  8. Droughts and floods over the upper catchment of the Blue Nile and their connections to the timing of El Niño and La Niña Events

    Directory of Open Access Journals (Sweden)

    M. A. H. Zaroug

    2013-08-01

    Full Text Available The Blue Nile originates from Lake Tana in the Ethiopian Highland and contributes about 67% of the discharge in the main Nile River. Previous studies investigated the relationship of sea surface temperature (SST in the Pacific Ocean (Nino 3.4 region to occurrence of floods and droughts in rainfall and river flow over the Nile basin. In this paper we focus on the dependence of occurrence of droughts and floods in the upper catchment of the Blue Nile on the timing of El Niño and La Niña events. Different events start in different times of the year and follow each other exhibiting different patterns and sequences. Here, we study the impact of this timing and temporal patterns on the Nile droughts and floods. We analyze discharge measurements (1965–2012 at the outlet of the upper catchment of the Blue Nile in relation to the El Niño index. When an El Niño event is followed by a La Niña event, there is a 67% chance for occurrence of an extreme flood. The association of start dates of El Niño with occurrence of droughts in the upper catchment of the Blue Nile is evaluated. An El Niño event that starts in (April–June is associated with a significant drought occurrence in 83% of the cases. We propose that observations as well as global model forecasts of SST during this season could be used in seasonal forecasting of the Blue Nile flow.

  9. Holocene palaeo-environments on the western coast of the Nile Delta: local and basin-wide forcing factors

    Science.gov (United States)

    Flaux, Clément; Véron, Alain; Marriner, Nick; el-Assal, Mena; Claude, Christelle; Morhange, Christophe

    2014-05-01

    The Canopic branch, which is today either silted up and cultivated or re-used in the modern drainage network, was the main channel for the western Nile Delta during Antiquity. Ancient Canopic flow used to supply the water network on the deltaic margin, including secondary tributaries, the Maryut lake, and irrigation agriculture and urban needs. We present new data obtained from a sediment core taken close to the palaeo-Canopic channel. Lead (Pb) isotopic analyses of bulk sediments, together with sedimentology, macro- and micro-fauna assemblages, magnetic susceptibility and radiocarbon dates provide evidence for environmental changes at the Canopic mouth in addition to changes in Nile sediment sources during the last 6000 years. Alternation of estuarine to lagoonal and peaty biofacies have recorded stages of transgression and progradation. 206Pb/207Pb analyses suggest a change in dominant sediment load from the White Nile to Blue Nile between 6000 and 5000 years cal. BP. The dataset is then compared and contrasted with previous studies, including: (1) a dense grid of dated bio-sedimentological cores data from the northwestern Nile Delta; (2) strontium isotope records of water and sediment fluxes on the delta; and (3) geochemical records from offshore sediment cores. Our analysis attempts to date and discriminate between basin-wide and regional to local forcing agents driving environmental changes at the mouth of the Canopic. The three main factors discussed will include climatic forcing of Nile flow and load changes, relative sea-level variations, and human impacts on the Canopic flow.

  10. Optimal operation of a multipurpose multireservoir system in the Eastern Nile River Basin

    Directory of Open Access Journals (Sweden)

    Q. Goor

    2010-07-01

    Full Text Available The upper Blue Nile River Basin in Ethiopia is a largely untapped resource despite its huge potential for hydropower generation and irrigated agriculture. Controversies exist as to whether the numerous infrastructural development projects that are on the drawing board in Ethiopia will generate positive or negative externalities downstream in Sudan and Egypt. This study attempts at 1 examining the (re-operation of infrastructures, in particular the proposed reservoirs in Ethiopia and the High Aswan Dam and 2 assessing the economic benefits and costs associated with the storage infrastructures in Ethiopia and their spatial and temporal distribution. To achieve this, a basin-wide integrated hydro-economic model has been developed. The model integrates essential hydrologic, economic and institutional components of the river basin in order to explore both the hydrologic and economic consequences of various policy options and planned infrastructural projects. Unlike most of the deterministic economic-hydrologic models reported in the literature, a stochastic programming formulation has been adopted in order to: i understand the effect of the hydrologic uncertainty on management decisions, ii determine allocation policies that naturally hedge against the hydrological risk, and iii assess the relevant risk indicators. The study reveals that the development of four mega dams in the upper part of the Blue Nile Basin would change the drawdown refill cycle of the High Aswan Dam. Should the operation of the reservoirs be coordinated, they would enable an average annual saving of at least 2.5 billion m3 through reduced evaporation losses from the Lake Nasser. Moreover, the new reservoirs (Karadobi, Beko-Abo, Mandaya and Border in Ethiopia would have significant positive impacts on hydropower generation and irrigation in Ethiopia and Sudan: at the basin scale, the annual energy generation is boosted by 38.5 TWh amongst which 14.2 TWh due to storage

  11. Impacts of global change on the Nile basin: Options for hydropolitical reform in Egypt and Ethiopia

    OpenAIRE

    Martens, Anja Kristina

    2011-01-01

    This paper analyzes drivers of global change and their impacts on the current and future availability and accessibility of water resources in the Nile Basin. Drivers include changes in demography, climate, the socioeconomy, and politics, all of which are likely to increase the demand for freshwater and thus competition over its use across riparian countries. As a result of historic bilateral agreements, Egypt, as the most downstream country, uses the lion's share of the Nile's waters, which m...

  12. Assessing and managing water scarcity within the Nile River Transboundary Basin

    Science.gov (United States)

    Butts, M. B.; Wendi, D.; Jessen, O. Z.; Riegels, N. D.

    2012-04-01

    The Nile Basin is the main source of water in the North Eastern Region of Africa and is perhaps one of the most critical river basins in Africa as the riparian countries constitute 40% of the population on the continent but only 10% of the area. This resource is under considerable stress with rising levels of water scarcity, high population growth, watershed degradation, and loss of environmental services. The potential impacts of climate change may significantly exacerbate this situation as the water resources in the Nile Basin are critically sensitive to climate change (Conway, Hanson, Doherty, & Persechino, 2007). The motivation for this study is an assessment of climate change impacts and adaptation potential for floods and droughts within the UNEP project "Adapting to climate change induced water stress in the Nile River Basin", supported by SIDA. This project is being carried out as collaboration between DHI, the UK Met Office, and the Nile Basin Initiative (NBI). The Nile Basin exhibits highly diverse climatological and hydrological characteristics. Thus climate change impacts and adaptive capacity must be addressed at both regional and sub-basin scales. While the main focus of the project is the regional scale, sub-basin scale modelling is required to reflect variability within the basin. One of the major challenges in addressing this variability is the scarcity of data. This paper presents an initial screening modelling study of the water balance of the Nile Basin along with estimates of expected future impacts of climate change on the water balance. This initial study is focussed on the Ethiopian Highlands and the Lake Victoria regions, where the impact of climate change on rainfall is important. A robust sub-basin based monthly water balance model is developed and applied to selected sub-basins. The models were developed and calibrated using publicly available data. One of the major challenges in addressing this variability within the basin is the

  13. Spatial and temporal variability of rainfall in the Nile Basin

    Directory of Open Access Journals (Sweden)

    C. Onyutha

    2014-10-01

    Full Text Available Spatio-temporal variability in annual and seasonal rainfall totals were assessed at 37 locations of the Nile Basin in Africa using quantile perturbation method. To get insight into the spatial difference in rainfall statistics, the stations were grouped based on the pattern of the long-term mean of monthly rainfall and that of temporal variability. To find the origin of the driving forces for the temporal variability in rainfall, correlation analyses were carried out using global monthly sea level pressure and surface temperature. Further investigations to support the obtained correlations were made using a total of 10 climate indices. It was possible to obtain 3 groups of stations; those within the equatorial region (A, Sudan and Ethiopia (B, and Egypt (C. For group A, annual rainfall was found to be below (above the reference during the late 1940s to 1950s (1960s to mid 1980s. Conversely for groups B and C, the period 1930s to late 1950s (1960s to 1980s was characterized by anomalies being above (below the reference. For group A, significant linkages were found to Niño 3, Niño 3.4 and the North Atlantic and Indian Ocean drivers. Correlations of annual rainfall of group A with Pacific Ocean-related climate indices were inconclusive. With respect to the main wet seasons, the June to September rainfall of group B has strong connection to the influence from the Indian Ocean. For the March to May (October to February rainfall of group A (C, possible links to the Atlantic and Indian Oceans were found.

  14. Assessment of Undiscovered Oil and Gas Resources of the Nile Delta Basin Province, Eastern Mediterranean

    Science.gov (United States)

    Kirschbaum, Mark A.; Schenk, Christopher J.; Charpentier, Ronald R.; Klett, Timothy R.; Brownfield, Michael E.; Pitman, Janet K.; Cook, Troy A.; Tennyson, Marilyn E.

    2010-01-01

    The U.S. Geological Survey estimated means of 1.8 billion barrels of recoverable oil, 223 trillion cubic feet of recoverable gas, and 6 billion barrels of natural gas liquids in the Nile Delta Basin Province using a geology-based assessment methodology.

  15. A molecular survey on cystic echinococcosis in Sinnar area,Blue Nile state (Sudan)

    Institute of Scientific and Technical Information of China (English)

    Kamal Ibrahim; Romig Thomas; Kern Peter; Rihab All Omer

    2011-01-01

    Background Cystic echinococcosis (CE) is a zoonosis caused by the cestodes of the Echinococcus species. Its life cycle involves dogs and other canids as definitive hosts for the intestinal tapeworm, as well as domestic and wild ungulates as intermediate hosts for the tissue-invading metacestode (larval) stage. The disease has a special impact on disadvantaged pastoralist communities and is listed now among the three top priority neglected tropical disease (NTD).Therefore, CE is a neglected disease even in high endemicity regions. This study aimed at investigation of the prevalence of CE in different animals slaughtered for food consumption in Sinnar area, Blue Nile states in Sudan.Methods A survey of CE in livestock was conducted from April 2009 to March 2011 in Sinnar area, Blue Nile state in Sudan. Location, parasitological status and fertility conditions were determined. In addition, 120 hydatid cysts (30 from camels, 62 from cattle and 28 from sheep) were examined by polymerase chain reaction (PCR) and mitochondrial gene sequencing for the genetic allocation of Echinococcus strains or species Results The prevalence of CE was 29.7% (30/101) in camels, 2.7% (62/2310) in cattle and 0.6% (26/4378) in sheep. It was shown that infection rates increased with age in camels, cattle and sheep. In camels, 67% (20/30) of the infected animals were aged between 2-5 years whereas 58% (36/62) of the infected cattle were >5 years. In sheep, the prevalence rate was distributed equally between animals ranging 2-5 years and >5 years. Even though multiple cysts were found in some animals, the average number of cysts per animal was close to 1 in all examined species. Lungs were found to be the predilection sites for the parasite in both camels and cattle, while most of the cysts found in sheep were located in the liver. About 63.4% of cysts encountered in camels were considered as large (5-7 cm), whereas those in cattle and sheep were medium (2-4 cm) and small (<2

  16. An outbreak of bovine trypanosomiasis in the Blue Nile State, Sudan

    Directory of Open Access Journals (Sweden)

    Nakamura Ichiro

    2011-05-01

    Full Text Available Abstract Background In this paper, we report an outbreak of bovine trypanosomiasis in Kurmuk District, Blue Nile State, Sudan that involved an infection with four Trypanosoma species in cattle. The outbreak occurred in June 2010 when indigenous cattle, mainly Kenana and Fulani breed types, crossed the national Sudanese border to Ethiopia and returned. A veterinarian was notified of massive deaths in the cattle populations that recently came from Ethiopia. All animals involved in the outbreak were from the nomadic Fulani group and resident local cattle were not infected and no death has been reported among them. A total of 210 blood samples were collected from the ear vein of cattle. A few samples were also collected from other domestic animals species. Parasitological examinations including hematocrit centrifugation techniques (HCT and Giemsa-stained thin blood films were carried out. ITS1-PCR, which provides a multi-species-specific diagnosis in a single PCR, was performed. Findings Parasitological examinations revealed that 43% (91/210 of the affected cattle population was infected with two morphologically distinct trypanosomes. Seventy animals (33.3% were infected with T. vivax and twenty one (10% with T. congolense. In contrast, ITS1-PCR was able to identify four Trypanosoma species namely T. vivax, T. congolense, T. simiae and T. brucei in 56.7% (80/141. T. brucei showed the highest prevalence of 36.9% (52/141 and the lowest 19% (27/141 was displayed by T. congolense. Furthermore, and because ITS1-PCR could not differentiate between T. brucei subspecies, serum resistance-associated (SRA gene based PCR was used to detect the human T. brucei rhodesiense in T. brucei positive samples. None of the samples was shown positive for T. b. rhodesiense. The identity of the 400 bp PCR product originating from T. simiae, was further confirmed by sequencing and subsequent phylogenetic analysis. Conclusions The outbreak of bovine trypanosomiasis occurred

  17. Preparation of graphene/nile blue nanocomposite: Application for oxygen reduction reaction and biosensing

    International Nuclear Information System (INIS)

    Highlights: •New nanocomposite is synthesized by electrochemical polymerization of Nile blue and reduction of GO on GCE. •The nanocomposite is characterized by SEM, UV–vis and electrochemical methods. •High electrocatalytic activity was observed for O2 reduction on GNs-NB nanocomposite. •GCE-GNs-NBpoly was tested successfully for immobilization of GOx and detection of glucose. -- Abstract: Nile blue/graphene (NB-GNs) nanocomposite was synthesized for the first time via a green and effective one-step electrochemical method, allowing to reduce graphene oxide (GO) and NB on the glassy carbon electrode (GCE) simultaneously and construct GCE-GNs-NBpoly composite. The composite was characterized by scanning electron microscopy (SEM), UV–Vis spectroscopy, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The electrochemical results obtained in the absence of any redox probe, where NB was active, allowed to trace step-by-step addition of the NB-GNs nanocomposite onto the GCE electrode surface, supporting formation of the GCE-GNs-NBpoly composite. The electrocatalytic activity of the as-prepared GCE-GNs-NBpoly towards O2 reduction was studied in neutral medium. The results revealed excellent electrocatalytic performance for two-electron reduction of oxygen, suggesting its potential application as metal-free electrocatalysts for O2 reduction reaction. Application of the GCE-GNs-NBpoly in electrochemical biosensing was demonstrated by immobilization of glucose oxidase (GOx) on the surface of GCE-GNs-NBpoly, and then, using it for sensing of glucose. The biosensor exhibited a linear response, from 0.2 to 2.0 mM glucose, with a low detection limit, 2.1 μM, and high sensitivity, 67.0 μA mM−1 cm−2, obtained by cyclic voltammetry method. The proposed biosensor was successfully tested for determination of glucose in blood serum samples

  18. Hydrological Balance of Lake Tana, Upper Blue Nile Basin, Ethiopia

    NARCIS (Netherlands)

    Rientjes, Tom H.M.; Perera, Janaka B.U.; Haile, Alemseged T.; Gieske, Ambro S.M.; Booij, Martijn J.; Reggiani, Paolo; Melesse, Assefa M.

    2011-01-01

    In recent years, few studies are presented on the water balance of Lake Tana. In these studies, the water balance is closed by unknown runoff contributions from ungauged catchments. Studies relied on simple procedures of area comparison to estimate runoff from ungauged catchments. In this study, emp

  19. Effect of Bias Correction of Satellite-Rainfall Estimates on Runoff Simulations at the Source of the Upper Blue Nile

    Directory of Open Access Journals (Sweden)

    Emad Habib

    2014-07-01

    Full Text Available Results of numerous evaluation studies indicated that satellite-rainfall products are contaminated with significant systematic and random errors. Therefore, such products may require refinement and correction before being used for hydrologic applications. In the present study, we explore a rainfall-runoff modeling application using the Climate Prediction Center-MORPHing (CMORPH satellite rainfall product. The study area is the Gilgel Abbay catchment situated at the source basin of the Upper Blue Nile basin in Ethiopia, Eastern Africa. Rain gauge networks in such area are typically sparse. We examine different bias correction schemes applied locally to the CMORPH product. These schemes vary in the degree to which spatial and temporal variability in the CMORPH bias fields are accounted for. Three schemes are tested: space and time-invariant, time-variant and spatially invariant, and space and time variant. Bias-corrected CMORPH products were used to calibrate and drive the Hydrologiska Byråns Vattenbalansavdelning (HBV rainfall-runoff model. Applying the space and time-fixed bias correction scheme resulted in slight improvement of the CMORPH-driven runoff simulations, but in some instances caused deterioration. Accounting for temporal variation in the bias reduced the rainfall bias by up to 50%. Additional improvements were observed when both the spatial and temporal variability in the bias was accounted for. The rainfall bias was found to have a pronounced effect on model calibration. The calibrated model parameters changed significantly when using rainfall input from gauges alone, uncorrected, and bias-corrected CMORPH estimates. Changes of up to 81% were obtained for model parameters controlling the stream flow volume.

  20. Tropical dryland agroforestry on clay soils: : Analysis of systems based on Acacia senegal in the Blue Nile region, Sudan

    OpenAIRE

    Raddad, Elamin Yousif Abdalla

    2006-01-01

    Acacia senegal, the gum arabic producing tree, is the most important component in traditional dryland agroforestry systems in the Blue Nile region, Sudan. The aim of the present study was to provide new knowledge on the potential use of A. senegal in dryland agroforestry systems on clay soils, as well as information on tree/crop interaction, and on silvicultural and management tools, with consideration on system productivity, nutrient cycling and sustainability. Moreover, the aim was also to ...

  1. Nile blue shows its true colors in gas-phase absorption and luminescence ion spectroscopy

    Science.gov (United States)

    Stockett, M. H.; Houmøller, J.; Brøndsted Nielsen, S.

    2016-09-01

    Nile blue is used extensively in biology as a histological stain and fluorescent probe. Its absorption and emission spectra are strongly solvent dependent, with variations larger than 100 nm. The molecule is charged due to an iminium group, and it is therefore an obvious target for gas-phase ion spectroscopy. Here we report the absorption and emission spectra of the mass-selected bare ions isolated in vacuo, and based on our results we revisit the interpretation of solution-phase spectra. An accelerator mass spectrometer was used for absorption spectroscopy where the absorption is represented by the yield of photofragment ions versus excitation wavelength (action spectroscopy). The luminescence experiments were done with a newly built ion trap setup equipped with an electrospray ion source, and some details on the mass selection technique will be given which have not been described before. In vacuo, the absorption and emission maxima are at 580 ± 10 nm and 628 ± 1 nm. These values are somewhat blue-shifted relative to those obtained in most solvents; however, they are much further to the red than those in some of the most non-polar solvents. Furthermore, the Stokes shift in the gas phase (1300 cm-1) is much smaller than that in these non-polar solvents but similar to that in polar ones. An explanation based on charge localization by solvent dipoles, or by counterions in some non-polar solvents, can fully account for these findings. Hence in the case of ions, it is nontrivial to establish intrinsic electronic transition energies from solvatochromic shifts alone.

  2. Heterogeneous photocatalytic degradation of nile blue dye in aqueous BiOCl suspensions

    Science.gov (United States)

    Sarwan, Bhawna; Pare, B.; Acharya, A. D.

    2014-05-01

    Bismuth oxychloride (BiOCl) was synthesized by hydrolysis method. Several analytical tools such as X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Brunauer-Emmett-Teller (BET) surface area, X-ray photoelectron spectroscopic, and energy-dispersive spectroscopic techniques were used to characterize the sample. The prepared material had average pore diameter of about 7-10 nm and the BET surface area of BiOCl was 40 m2 g-1. The analysis of hydroxyl radicals (•OH) formation was performed by fluorescence technique. The intermediates and the final products of degradation were detected by high-performance liquid chromatography-photodiode array-electrospray ionization-mass spectrometry (HPLC-ESI-DAD-MS) technology. The degradation of nile blue (NB) dye was mainly attributed to the destruction of the conjugated structure, and after that the intermediates were transformed into small molecules mainly phenol, aniline, etc., which were mineralized to water and carbon dioxide. During three recycles, the catalyst did not exhibit any significant loss of photocatalytic activity, confirming that the photocatalyst is essentially stable. The NB oxidation was evaluated by the decrease in total organic carbon (TOC) content. The formation of NO3- and the evolution of CO2 revealed complete mineralization of aqueous NB during the photocatalytic process by this photocatalyst.

  3. 20,000 years of Nile River dynamics and environmental changes in the Nile catchment area as inferred from Nile upper continental slope sediments

    Science.gov (United States)

    Revel, Marie; Ducassou, E.; Skonieczny, C.; Colin, C.; Bastian, L.; Bosch, D.; Migeon, S.; Mascle, J.

    2015-12-01

    Multi-proxy analysis of two marine sediment cores (MS27PT and MD04-2726) from the Nile continental slope provides evidence of changes in Nile sediment discharge related to changes in Ethiopian African Monsoon (EAM) precipitation, and allows us to reconstruct changes in Nile River runoff, vegetation and erosion in the Nile headwaters. Sediment element composition and neodymium isotopic composition reveal significant changes in clastic sediment provenance, with sources oscillating between a Saharan aeolian contribution during the Last Glacial Maximum/deglacial transition and during the Late Holocene, and a Blue/Atbara Nile fluvial contribution during the African Humid Period (AHP). This study provides a new understanding of past environmental changes. Between 14.6 and 14.13 ka there was a major input of sediments from the Ethiopian Highlands, consistent with a stronger EAM at that time. Climate in the Nile basin was wetter between 14.8 and 8.4 ka, with a corresponding increase in Blue Nile water and sediment discharge via the main Nile into the Eastern Mediterranean. The gradual climatic transition from the AHP to the present-day dry climate was reflected in a decrease in Blue Nile sediment deposition and flood discharge between 8.4 and 3.7 ka, with aridity at a maximum between 3.7 and 2.6 ka. The onset of drier conditions in the Blue Nile basin seems to have begun before the 8.2 ka cooling event in the North Atlantic. We speculate that the climatic change from the wet AHP to the dry late Holocene may have been a result of a break in the low latitude dynamic equilibrium between climate, vegetation and erosion, which may in turn have affected the climate in higher latitudes. Reduced Nile flow may also have had an impact on Levantine Intermediate Water originating in the Eastern Mediterranean through an increase in intermediate water formation.

  4. Predictive modeling of West Nile virus transmission risk in the Mediterranean Basin: how far from landing?

    Science.gov (United States)

    Chevalier, Véronique; Tran, Annelise; Durand, Benoit

    2014-01-01

    The impact on human and horse health of West Nile fever (WNF) recently and dramatically increased in Europe and neighboring countries. Involving several mosquito and wild bird species, WNF epidemiology is complex. Despite the implementation of surveillance systems in several countries of concern, and due to a lack of knowledge, outbreak occurrence remains unpredictable. Statistical models may help identifying transmission risk factors. When spatialized, they provide tools to identify areas that are suitable for West Nile virus transmission. Mathematical models may be used to improve our understanding of epidemiological process involved, to evaluate the impact of environmental changes or test the efficiency of control measures. We propose a systematic literature review of publications aiming at modeling the processes involved in WNF transmission in the Mediterranean Basin. The relevance of the corresponding models as predictive tools for risk mapping, early warning and for the design of surveillance systems in a changing environment is analyzed. PMID:24362544

  5. Predictive Modeling of West Nile Virus Transmission Risk in the Mediterranean Basin: How Far from Landing?

    Directory of Open Access Journals (Sweden)

    Véronique Chevalier

    2013-12-01

    Full Text Available The impact on human and horse health of West Nile fever (WNF recently and dramatically increased in Europe and neighboring countries. Involving several mosquito and wild bird species, WNF epidemiology is complex. Despite the implementation of surveillance systems in several countries of concern, and due to a lack of knowledge, outbreak occurrence remains unpredictable. Statistical models may help identifying transmission risk factors. When spatialized, they provide tools to identify areas that are suitable for West Nile virus transmission. Mathematical models may be used to improve our understanding of epidemiological process involved, to evaluate the impact of environmental changes or test the efficiency of control measures. We propose a systematic literature review of publications aiming at modeling the processes involved in WNF transmission in the Mediterranean Basin. The relevance of the corresponding models as predictive tools for risk mapping, early warning and for the design of surveillance systems in a changing environment is analyzed.

  6. Assessing the Effects of Climate Change on Drought Risk for the Nile River Basin

    Science.gov (United States)

    Strzepek, K. M.; Boehlert, B. B.; Vogel, R. M.

    2012-12-01

    Approximately 90 percent of the Nile River runoff is generated within two regions—the Ethiopian highlands and the Lake Victoria and Equatorial Lakes—that have historically contrasting precipitation regimes. As a result of uncorrelated interannual rainfall variability, meteorological droughts in one region are typically offset by wetter periods in the other, thus having a moderating effect on downstream Nile river flow to Sudan and Egypt. Under climate change, the drivers of these contrasting rainfall regimes (including the annual migration of the Inter Tropical Convergence Zone) may be fundamentally altered such that droughts become correlated between these regions, leading to unprecedented low flows in the downstream Nile. The water management challenges that would result are likely to be exacerbated if climate change increases drought occurrence and intensity across the basin. In this research, we first assess the effect of climate change on drought frequency and intensity across eight Nile subbasins by applying the Standardized Precipitation Index (SPI) and the Palmer Drought Severity Index (PDSI) to the full suite of 22 Intergovernmental Panel on Climate Change General Circulation Models for three IPCC-SRES emissions scenarios (B1, A1B, and A2 from the Special Report on Emissions Scenarios (SRES)). We then use these outputs to evaluate how climate change affects the correlation of drought occurrence and intensity between the Ethiopian highlands and the Lake Victoria and Equatorial Lakes regions. In the first inquiry, we find that the frequency of drought over the next century based on precipitation alone (SPI) is projected to increase in the northern Nile basin, and decrease in the southern regions. Drought frequencies based on both precipitation and temperature (PDSI) are projected to increase across most of the Nile basin, however, with almost universally experienced increases in drought risk by the late 21st century. For both measures, the Ethiopia

  7. ALEXI analysis of water consumption in the Nile Basin

    Science.gov (United States)

    Remote sensing can be used to generate diagnostic estimates of evapotranspiration (ET) that provide information regarding consumptive water use across landscapes. These satellite-based assessments can be a valuable complement to prognostic simulations of basin-scale water budgets, providing an inde...

  8. Heterogeneous photocatalytic degradation of nile blue dye in aqueous BiOCl suspensions

    Energy Technology Data Exchange (ETDEWEB)

    Sarwan, Bhawna, E-mail: sarbhawna@gmail.com [Laboratory of Photocatalysis, Department of Chemistry, Madhav Science Post Graduate College, Vikram University, Ujjain 456010, Madhya Pradesh (India); Pare, B. [Laboratory of Photocatalysis, Department of Chemistry, Madhav Science Post Graduate College, Vikram University, Ujjain 456010, Madhya Pradesh (India); Acharya, A.D. [School of Studies in Physics, Vikram University, Ujjain 456010, Madhya Pradesh (India)

    2014-05-01

    Graphical abstract: - Highlights: • Photocatalytic degradation of NB dye was carried out by using synthesized BiOCl. • Hydrolysis method was presented. • Formation of {sup •} OH verified by fluorescence technology. • BiOCl possessed highly adsorption capacity for organic dye. • The intermediates and the final products of degradation were detected. • Mineralization of NB confirmed by TOC and nitrate anions production. - Abstract: Bismuth oxychloride (BiOCl) was synthesized by hydrolysis method. Several analytical tools such as X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Brunauer–Emmett–Teller (BET) surface area, X-ray photoelectron spectroscopic, and energy-dispersive spectroscopic techniques were used to characterize the sample. The prepared material had average pore diameter of about 7–10 nm and the BET surface area of BiOCl was 40 m{sup 2} g{sup −1}. The analysis of hydroxyl radicals ({sup •} OH) formation was performed by fluorescence technique. The intermediates and the final products of degradation were detected by high-performance liquid chromatography–photodiode array-electrospray ionization-mass spectrometry (HPLC–ESI-DAD-MS) technology. The degradation of nile blue (NB) dye was mainly attributed to the destruction of the conjugated structure, and after that the intermediates were transformed into small molecules mainly phenol, aniline, etc., which were mineralized to water and carbon dioxide. During three recycles, the catalyst did not exhibit any significant loss of photocatalytic activity, confirming that the photocatalyst is essentially stable. The NB oxidation was evaluated by the decrease in total organic carbon (TOC) content. The formation of NO{sub 3}{sup −} and the evolution of CO{sub 2} revealed complete mineralization of aqueous NB during the photocatalytic process by this photocatalyst.

  9. Building Climate Resilience in the Blue Nile/Abay Highlands: A Framework for Action

    Directory of Open Access Journals (Sweden)

    Belay Simane

    2012-02-01

    Full Text Available Ethiopia has become warmer over the past century and human induced climate change will bring further warming over the next century at unprecedented rates. On the average, climate models show a tendency for higher mean annual rainfall and for wetter conditions, in particular during October, November and December, but there is much uncertainty about the future amount, distribution, timing and intensity of rainfall. Ethiopia’s low level of economic development, combined with its heavy dependence on agriculture and high population growth rate make the country particularly susceptible to the adverse effects of climate change. Nearly 90% of Ethiopia’s population lives in the Highlands, which include the critical Blue Nile (Abay Highlands—a region that holds special importance due to its role in domestic agricultural production and international water resources. A five year study of climate vulnerability and adaptation strategies in communities of Choke Mountain, located in the center of the Abay Highlands, has informed a proposed framework for enhancing climate resilience in communities across the region. The framework is motivated by the critical need to enhance capacity to cope with climate change and, subsequently, to advance a carbon neutral and climate resilient economy in Ethiopia. The implicit hypothesis in applying a research framework for this effort is that science-based information, generated through improved understanding of impacts and vulnerabilities of local communities, can contribute to enhanced resilience strategies. We view adaptation to climate change in a wider context of changes, including, among others, market conditions, the political-institutional framework, and population dynamics. From a livelihood perspective, culture, historical settings, the diversity of income generation strategies, knowledge, and education are important factors that contribute to adaptive capacities. This paper reviews key findings of the Choke

  10. Shifting Sediment Sources in the Quaternary Nile

    Science.gov (United States)

    Woodward, Jamie; Macklin, Mark; Fielding, Laura; Millar, Ian; Williams, Martin

    2016-04-01

    Invited Paper The Nile basin contains the longest river channel system in the world and drains about one tenth of the African continent. A dominant characteristic of the modern Nile is the marked spatial and temporal variability in the flux of water and sediment. Because the major headwater basins of the Nile are linked to key elements of the global climate system, the sedimentary records in the basin have attracted good deal of attention from the Quaternary palaeoclimate and palaeohydrology communities. Various approaches (from heavy minerals to strontium isotopes) have been employed to examine present and past patterns of sediment yield in the basin. A good deal of work has been carried out on the long sediment records in the delta and offshore which provide high resolution archives of hydrological changes in the upstream basin as well fluctuations in the input of dust from the desert. The sediment load of the modern desert Nile (downstream of Khartoum) is dominated by sediment inputs from the Blue Nile (61 +/- 5%) and Atbara (35 +/- 4%), whilst the White Nile contribution is meagre (3 +/- 2%) (Padoan et al. 2011). Recent work has shown that these values were very different during humid phases of the Quaternary when stronger Northern Hemisphere summer insolation produced wetter conditions across North Africa. In the early Holocene, for example, the Nile floodplain in Northern Sudan shows a tributary wadi input of 40-50%. This paper will review three decades of work on the sediment delivery dynamics of the Quaternary Nile and explore their palaeoclimatic implications. Padoan, M., Garzanti, E., Harlavan, Y., Villa, I.M. (2011) Tracing Nile sediment sources by Sr and Nd isotope signatures (Uganda, Ethiopia, Sudan). Geochim. Cosmochim. Acta 75 (12), 3627-3644.

  11. Screening reservoir systems by considering the efficient trade-offs—informing infrastructure investment decisions on the Blue Nile

    Science.gov (United States)

    Geressu, Robel T.; Harou, Julien J.

    2015-12-01

    Multi-reservoir system planners should consider how new dams impact downstream reservoirs and the potential contribution of each component to coordinated management. We propose an optimized multi-criteria screening approach to identify best performing designs, i.e., the selection, size and operating rules of new reservoirs within multi-reservoir systems. Reservoir release operating rules and storage sizes are optimized concurrently for each separate infrastructure design under consideration. Outputs reveal system trade-offs using multi-dimensional scatter plots where each point represents an approximately Pareto-optimal design. The method is applied to proposed Blue Nile River reservoirs in Ethiopia, where trade-offs between total and firm energy output, aggregate storage and downstream irrigation and energy provision for the best performing designs are evaluated. This proof-of concept study shows that recommended Blue Nile system designs would depend on whether monthly firm energy or annual energy is prioritized. 39 TWh/yr of energy potential is available from the proposed Blue Nile reservoirs. The results show that depending on the amount of energy deemed sufficient, the current maximum capacities of the planned reservoirs could be larger than they need to be. The method can also be used to inform which of the proposed reservoir type and their storage sizes would allow for the highest downstream benefits to Sudan in different objectives of upstream operating objectives (i.e., operated to maximize either average annual energy or firm energy). The proposed approach identifies the most promising system designs, reveals how they imply different trade-offs between metrics of system performance, and helps system planners asses the sensitivity of overall performance to the design parameters of component reservoirs.

  12. Hydroclimatology of the Nile: results from a regional climate model

    Directory of Open Access Journals (Sweden)

    Y. A. Mohamed

    2005-01-01

    Full Text Available This paper presents the result of the regional coupled climatic and hydrologic model of the Nile Basin. For the first time the interaction between the climatic processes and the hydrological processes on the land surface have been fully coupled. The hydrological model is driven by the rainfall and the energy available for evaporation generated in the climate model, and the runoff generated in the catchment is again routed over the wetlands of the Nile to supply moisture for atmospheric feedback. The results obtained are quite satisfactory given the extremely low runoff coefficients in the catchment. The paper presents the validation results over the sub-basins: Blue Nile, White Nile, Atbara river, the Sudd swamps, and the Main Nile for the period 1995 to 2000. Observational datasets were used to evaluate the model results including radiation, precipitation, runoff and evaporation data. The evaporation data were derived from satellite images over a major part of the Upper Nile. Limitations in both the observational data and the model are discussed. It is concluded that the model provides a sound representation of the regional water cycle over the Nile. The sources of atmospheric moisture to the basin, and location of convergence/divergence fields could be accurately illustrated. The model is used to describe the regional water cycle in the Nile basin in terms of atmospheric fluxes, land surface fluxes and land surface-climate feedbacks. The monthly moisture recycling ratio (i.e. locally generated/total precipitation over the Nile varies between 8 and 14%, with an annual mean of 11%, which implies that 89% of the Nile water resources originates from outside the basin physical boundaries. The monthly precipitation efficiency varies between 12 and 53%, and the annual mean is 28%. The mean annual result of the Nile regional water cycle is compared to that of the Amazon and the Mississippi basins.

  13. A Novel Reagentless Biosensor Constructed by Layer-by-Layer Assembly of HRP and Nile Blue Premixed with Polyanion

    Institute of Scientific and Technical Information of China (English)

    Shao Ming YANG; Yang Mei LI; Xiu Ming JIANG; Xian Fu LIN

    2005-01-01

    A novel reagentless biosensor constructed by the organic dye nile blue (NB) and horseradish peroxidase (HRP) has been fabricated via layer-by-layer (LBL) self-assembly technique. NB premixed with polyanion poly (sodium-p-styrenesulfonate) (PSS) acts as the mediator between the immobilized HRP and the electrode surface. The response of the biosensor to hydrogen peroxide has been investigated. The linear range of the biosensor to hydrogen peroxide was from 0.20 mmol/L to 7.03 mmol/L with a sensitivity of 8.45μA/(mmol/L).

  14. Epidemiology of West Nile Disease in Europe and in the Mediterranean Basin from 2009 to 2013

    Directory of Open Access Journals (Sweden)

    Daria Di Sabatino

    2014-01-01

    Full Text Available West Nile virus (WNV transmission has been confirmed in the last four years in Europe and in the Mediterranean Basin. An increasing concern towards West Nile disease (WND has been observed due to the high number of human and animal cases reported in these areas confirming the importance of this zoonosis. A new epidemiological scenario is currently emerging: although new introductions of the virus from abroad are always possible, confirming the epidemiological role played by migratory birds, the infection endemisation in some European territories today is a reality supported by the constant reoccurrence of the same strains across years in the same geographical areas. Despite the WND reoccurrence in the Old World, the overwintering mechanisms are not well known, and the role of local resident birds or mosquitoes in this context is poorly understood. A recent new epidemiological scenario is the spread of lineage 2 strain across European and Mediterranean countries in regions where lineage 1 strain is still circulating creating favourable conditions for genetic reassortments and emergence of new strains. This paper summarizes the main epidemiological findings on WNV occurrence in Europe and in the Mediterranean Basin from 2009 to 2013, considering potential future spread patterns.

  15. Hydrologic impacts of climate change on the Nile River basin: Implications of the 2007 IPCC climate scenarios

    NARCIS (Netherlands)

    Beyene, T.; Lettenmaier, D.P.; Kabat, P.

    2010-01-01

    We assess the potential impacts of climate change on the hydrology and water resources of the Nile River basin using a macroscale hydrology model. Model inputs are bias corrected and spatially downscaled 21st Century simulations from 11 General Circulation Models (GCMs) and two global emissions scen

  16. Identifying residence times and streamflow generation processes using δ18O and δ2H in meso-scale catchments in the Abay/Upper Blue Nile, Ethiopia

    Directory of Open Access Journals (Sweden)

    S. Tekleab

    2013-08-01

    Full Text Available Measurements of the stable isotopes oxygen-18 (18O and deuterium (2H were carried out in two meso-scale catchments, Chemoga (358 km2 and Jedeb (296 km2 south of Lake Tana, Abay/Upper Blue Nile basin, Ethiopia. The region is of paramount importance for the water resources in the Nile basin. Stable isotope composition in precipitation, spring water and streamflow were analyzed (i to characterize the spatial and temporal variations of water fluxes; (ii to estimate the mean residence time of water using a sine wave regression approach; and (iii to identify runoff components using classical two component hydrograph separations at a seasonal time scale. The results show that the isotopic composition of precipitation exhibit marked seasonal variations, which suggests different sources of moisture generation for the rainfall in the study area. The Atlantic–Indian ocean, Congo basin, and the Sud swamps are the likely the potential moisture source areas during the main rainy (summer season. While, the Indian–Arabian, and Mediterranean Sea moisture source areas during little rain (spring, and dry (winter seasons. The spatial variation of the isotopic composition is affected by the amount effect and to less extent by altitude and temperature effects. A mean altitude effect of −0.12‰ (100 m−1 for 18O and −0.58‰ (100 m−1 for 2H were discernable in precipitation isotope composition. The seasonal variations of the isotopic signature of the spring water exhibit a damped response as compared to the river waters, which shows that the spring water has longer residence times than the river water. Results from the hydrograph separation at a seasonal time scale indicate the dominance of event water with an average of 71% and 64% of the total runoff during the wet season in the Chemoga and Jedeb catchment, respectively. The stable isotope compositions of streamflow samples were damped compared to the input function of precipitation for both catchments

  17. Concentration-dependent energy transfer studies in ternary dye mixture of Stilbene-420, Coumarin-540 and Nile Blue

    Science.gov (United States)

    Sharma, A. K.; Ahlawat, D. S.; Mohan, D.; Singh, R. D.

    2009-01-01

    The energy transfer studies in the case of ternary dye mixture [Stilbene-420 (donor) + Coumarin-540 (intermediator) + Nile Blue (acceptor)] have been done and discussed through optical gain characteristics at various acceptor concentrations under nitrogen laser excitation. The concentration of the other two dyes were kept constant. It is observed that the concentration of the acceptor dye plays a very critical role in energy transfer dye laser (ETDL) as small change in its concentration varies the intensity of the laser output in the red region by large amount. Also, the highest laser output in the red region is obtained when the concentration of the acceptor dye is slightly higher than that of the intermediator dye. The present studies are helpful in deciding the optimum concentration of the acceptor dye to be used in ternary dye mixture for maximum gain and tuning range. The ternary dye mixture under study provides an ETDL tuning range up to 700 nm.

  18. Adsorption of Nile Blue A from Wastewater Using Magnetic Multi-Walled Carbon Nanotubes: Kinetics and Equilibrium Studies

    Directory of Open Access Journals (Sweden)

    Mehrnaz Ghoochian

    2016-04-01

    Full Text Available Background: Synthetic dyes are serious pollutants and wide ranges of methods have been employed for their removal from aquatic systems. We studied the adsorption of "Nile blue A" (NBA, an anionic dye, from aqueous solution by oxidized multi-walled carbon nanotubes (MWCNTs. Methods: Scanning electron microscope and Fourier transform infrared spectroscopy were used to characterize function groups produced at MWCNTs surface. Kinetics and adsorption isotherms of NBA, the effect of temperature, pH, contact time and initial dosage of nanotubes on the adsorption capacity were also assessed. The experimental data were analyzed by Langmuir and Freundlich models. Results: Most of the dye was removed in the first 5 min and best adsorption percentage was at pH 7.0. The equilibrium reached at 45 min. The experimental data were analyzed by Langmuir and Freundlich models and the results fitted well with the Freundlich model. The adsorption kinetic data were analyzed using first-order and the pseudo-second order model and the adsorption kinetic data of NBA dye onto MWCNTs fitted the pseudo-second order model. The maximum adsorption capacity was obtained as 169.49 mg g-1. Conclusion: Freundlich model suggested that the adsorption process followed heterogeneous distribution onto MWCNTs and pseudo-second model of adsorption implied that chemical processes controlled the rate-controlling step. Oxidized MWCNTs could be used as an effective adsorbent for the removal of "Nile Blue A" dye. Oxidization of MWCNTs by nitric acid, improves the efficiency of NBA removal due to increases in functional groups and total number of adsorption sites.

  19. Hydroclimatology of the Nile: results from a regional climate model

    Directory of Open Access Journals (Sweden)

    Y. A. Mohamed

    2005-02-01

    Full Text Available This paper is the result of the first regional coupled climatic and hydrologic model of the Nile. For the first time the interaction between the climatic processes and the hydrological processes on the land surface have been fully coupled. The hydrological model is driven by the rainfall and the energy available for evaporation generated in the climate model, and the runoff generated in the catchment is again routed over the wetlands of the Nile to supply moisture for atmospheric feedback. The results obtained are surprisingly accurate given the extremely low runoff coefficients in the catchment.

    The paper presents model results over the sub-basins: Blue Nile, White Nile, Atbara river and the Main Nile for the period 1995 to 2000, but focuses on the Sudd swamp. Limitations in both the observational data and the model are discussed. It is concluded that the model provides a sound representation of the regional water cycle over the Nile. The model is used to describe the regional water cycle in the Nile basin in terms of atmospheric fluxes, land surface fluxes and land surface-climate feedbacks. The monthly moisture recycling ratio (i.e. locally generated/total precipitation over the Nile varies between 8 and 14%, with an annual mean of 11%, which implies that 89% of the Nile water resources originates from outside the basin physical boundaries. The monthly precipitation efficiency varies between 12 and 53%, and the annual mean is 28%. The mean annual result of the Nile regional water cycle is compared to that of the Amazon and the Mississippi basins.

  20. Critical review of SWAT applications in the upper Nile basin countries

    Science.gov (United States)

    van Griensven, A.; Ndomba, P.; Yalew, S.; Kilonzo, F.

    2012-09-01

    The Soil and Water Assessment Tool (SWAT) is an integrated river basin model that is widely applied within the Nile basin. Up to date, more than 20 peer-reviewed papers describe the use of SWAT for a variety of problems in the upper Nile basin countries, such as erosion modelling, land use and climate change impact modelling and water resources management. The majority of the studies are focused on locations in the tropical highlands in Ethiopia and around Lake Victoria. The popularity of SWAT is attributed to the fact that the tool is freely available and that it is readily applicable through the development of geographic information system (GIS) based interfaces and its easy linkage to sensitivity, calibration and uncertainty analysis tools. The online and free availability of basic GIS data that are required for SWAT made its applicability more straightforward even in data-scarce areas. However, the easy use of SWAT may not always lead to appropriate models which is also a consequence of the quality of the available free databases in these regions. In this paper, we aim at critically reviewing the use of SWAT in the context of the modelling purpose and problem descriptions in the tropical highlands of the Nile basin countries. To evaluate the models that are described in journal papers, a number of criteria are used to evaluate the model set-up, model performances, physical representation of the model parameters, and the correctness of the hydrological model balance. On the basis of performance indicators, the majority of the SWAT models were classified as giving satisfactory to very good results. Nevertheless, the hydrological mass balances as reported in several papers contained losses that might not be justified. Several papers also reported the use of unrealistic parameter values. More worrying is that many papers lack this information. For this reason, most of the reported SWAT models have to be evaluated critically. An important gap is the lack of

  1. Critical review of SWAT applications in the upper Nile basin countries

    Directory of Open Access Journals (Sweden)

    A. van Griensven

    2012-09-01

    Full Text Available The Soil and Water Assessment Tool (SWAT is an integrated river basin model that is widely applied within the Nile basin. Up to date, more than 20 peer-reviewed papers describe the use of SWAT for a variety of problems in the upper Nile basin countries, such as erosion modelling, land use and climate change impact modelling and water resources management. The majority of the studies are focused on locations in the tropical highlands in Ethiopia and around Lake Victoria. The popularity of SWAT is attributed to the fact that the tool is freely available and that it is readily applicable through the development of geographic information system (GIS based interfaces and its easy linkage to sensitivity, calibration and uncertainty analysis tools. The online and free availability of basic GIS data that are required for SWAT made its applicability more straightforward even in data-scarce areas. However, the easy use of SWAT may not always lead to appropriate models which is also a consequence of the quality of the available free databases in these regions. In this paper, we aim at critically reviewing the use of SWAT in the context of the modelling purpose and problem descriptions in the tropical highlands of the Nile basin countries. To evaluate the models that are described in journal papers, a number of criteria are used to evaluate the model set-up, model performances, physical representation of the model parameters, and the correctness of the hydrological model balance. On the basis of performance indicators, the majority of the SWAT models were classified as giving satisfactory to very good results. Nevertheless, the hydrological mass balances as reported in several papers contained losses that might not be justified. Several papers also reported the use of unrealistic parameter values. More worrying is that many papers lack this information. For this reason, most of the reported SWAT models have to be evaluated critically. An important gap is

  2. The Influence of Policy Discourses on multilevel water governance: a case study of the Equatorial Nile Basin

    OpenAIRE

    Hissen, Nina F.

    2014-01-01

    This research assesses how discourses on climate change and water security during policy making impact on actual water management, analysing the Equatorial Nile Basin and its riparian countries (Uganda, Kenya, Tanzania, Burundi, Rwanda and DR Congo) as a case study. The thesis looks at the significance of informal policy networks for water governance, and critically discusses the extent to which the framing of issues by these networks are reflected in the practical implementation of mul...

  3. Isotope geochemistry of water-sediments interaction downstream the Nile basin

    International Nuclear Information System (INIS)

    The environmental setup: Downstream the Nile basin, the river cuts for more than 2000km northward across the eastern Great Sahara to discharge into the Mediterranean. The Holocene fine-textured fluvial sediments are bounded, on the east and west, by desert plateaus and depressions along the floodplain and delta, whereas fluvio-marine sediments adjoin the river/ocean interface. Since several millennia, intense anthropogenic and biogenic activities started to locally impose its control on the involved aqueous and solid-phases of the fluvial environment when humans added a fourth dimension to the three-component physiography (river-desert-ocean) through classic cultivation under exceptional annual flood water supply. Gradually, the historic basin-irrigation hydrologic system has entirely been replaced by perennial pond-irrigation during the last 150 years and was completed by early 1970s. Extensive farming started to take place during the last 50 years in the satellite desert plateaus and depressions in close hydrologic connection to the floodplain and delta, depending either on surface water supply from the river (through long aqueducts) or depending on groundwater pumping. Also, land reclamation projects have transformed previously saline and low wetlands into cultivated areas with different degrees of success and failure during the last centuries in the north of the delta. This reclamation solely depends on surface water supply from open channels, and recently it also depends on re-use of drainage water flowing out from southern and middle delta lands as agricultural return flow. Sampling and Methods Isotope and hydro-geo-chemical observations were collected for several components in some parts downstream the Nile basin in Egypt in order to distinguish the major processes that control the operational system. Water and solid-phase samples (from river, irrigation open channels, drainage ditches, shallow phreatic water-table, moderately deep groundwater and surface

  4. The Challenges and Opportunities of Hydrologic Remote Sensing in Data-Poor Regions: Case Study of Nile River Basin

    Science.gov (United States)

    Hasan, E.; Kirstetter, P.; Zhang, K.; Hong, Y.

    2015-12-01

    The Nile River Basin (NRB) is one of the largest trans-boundary watercourses; it is the lifeline for more than 300 million people belonging to 11 African nations sharing the NRB. The riparian countries are challenged by their infirm relationships, lack of information sharing and insufficient monitoring stations. Thus, to understand the water future along the NRB under the changing climate, reliable, and sufficient information are needed. This to assess and understand: whether will be more rainfall and induced flooding events, or the drought conditions with less surface runoff will be dominant over the Nile Basin? In addition, to what extent the available remote sensing and model reanalysis data can substitute the lack of detailed ground information, and help to determine the size and risk associated to the climatic impact on the Nile Basin? In the current study, we utilizing multi-scale remote sensing, and model reanalysis datasets for hydrologic monitoring along the NRB in Africa. The list of remote sensing, and model reanalysis datasets that implemented: several MODIS satellite products such as the NDVI, LAI, LST, and LULC datasets. Three GRACE satellite derivative products: TWS, EWT, and DTWS, and TRMM satellite precipitation product. In addition to number of model reanalysis datasets including Global Precipitation Climatological Center (GPCC) datasets, Global Land Data Assimilation System (GLDAS) products, Climate Research Unit (CRU) datasets, Physical Science Division (PSD) gridded climate dataset, and in situ Global Runoff Data Centre (GRDC) datasets. The main objective of our research is to monitor the hydrological changes and the variation in water balance along the NRB. The study approach accomplished through: (1) developing a distributed storage changes based grid, (2) trend analysis and inter-annual variability shift detections using regime shift analysis, (3) define the water stress and water deficit periods along the Nile Basins, (4) applying multi

  5. Critical review of the application of SWAT in the upper Nile Basin countries

    Science.gov (United States)

    van Griensven, A.; Ndomba, P.; Yalew, S.; Kilonzo, F.

    2012-03-01

    The Soil and Water Assessment Tool (SWAT) is a hydrological simulation tool that is widely applied within the Nile basin. Up to date, more than 20 peer reviewed papers describe the use of SWAT for a variety of problems in the upper Nile basin countries, such as erosion modeling, land use modeling, climate change impact modeling and water resources management. The majority of the studies are clustered in the tropical highlands in Ethiopia and around Lake Victoria. The popularity of SWAT is attributed to the fact that the tool is freely available and that it is readily applicable through the development of Geographic Information System (GIS) based interfaces and its easy linkage to sensitivity, calibration and uncertainty analysis tools. The online and free availability of basic GIS data that are required for SWAT made its applicability more straight forward even in data scarce areas. However, the easy use of SWAT may not always lead to knowledgeable models. In this paper, we aim at critically reviewing the use of SWAT in the context of the modeling purpose and problem descriptions in the tropical highlands of the Nile Basin countries. A number of criteria are used to evaluate the model set-up, model performances, physical representation of the model parameters, and the correctness of the hydrological model balance. On the basis of performance indicators, the majority of the SWAT models were classified as giving satisfactory to very good results. Nevertheless, the hydrological mass balances as reported in several papers contained losses that might not be justified. Several papers also reported unrealistic parameter values. More worrying is that many papers lack this information. For this reason, it is difficult to give an overall positive evaluation to most of the reported SWAT models. An important gap is the lack of attention that is given to the vegetation and crop processes. None of the papers reported any adaptation to the crop parameters, or any crop related

  6. Critical review of the application of SWAT in the upper Nile Basin countries

    Directory of Open Access Journals (Sweden)

    A. van Griensven

    2012-03-01

    Full Text Available The Soil and Water Assessment Tool (SWAT is a hydrological simulation tool that is widely applied within the Nile basin. Up to date, more than 20 peer reviewed papers describe the use of SWAT for a variety of problems in the upper Nile basin countries, such as erosion modeling, land use modeling, climate change impact modeling and water resources management. The majority of the studies are clustered in the tropical highlands in Ethiopia and around Lake Victoria. The popularity of SWAT is attributed to the fact that the tool is freely available and that it is readily applicable through the development of Geographic Information System (GIS based interfaces and its easy linkage to sensitivity, calibration and uncertainty analysis tools. The online and free availability of basic GIS data that are required for SWAT made its applicability more straight forward even in data scarce areas. However, the easy use of SWAT may not always lead to knowledgeable models. In this paper, we aim at critically reviewing the use of SWAT in the context of the modeling purpose and problem descriptions in the tropical highlands of the Nile Basin countries. A number of criteria are used to evaluate the model set-up, model performances, physical representation of the model parameters, and the correctness of the hydrological model balance. On the basis of performance indicators, the majority of the SWAT models were classified as giving satisfactory to very good results. Nevertheless, the hydrological mass balances as reported in several papers contained losses that might not be justified. Several papers also reported unrealistic parameter values. More worrying is that many papers lack this information. For this reason, it is difficult to give an overall positive evaluation to most of the reported SWAT models. An important gap is the lack of attention that is given to the vegetation and crop processes. None of the papers reported any adaptation to the crop parameters, or

  7. Synthetic incorporation of Nile Blue into DNA using 2′-deoxyriboside substitutes: Representative comparison of (R- and (S-aminopropanediol as an acyclic linker

    Directory of Open Access Journals (Sweden)

    Daniel Lachmann

    2010-02-01

    Full Text Available The Nile Blue chromophore was incorporated into oligonucleotides using “click” chemistry for the postsynthetic modification of oligonucleotides. These were synthesized using DNA building block 3 bearing an alkyne group and reacted with the azide 4. (R-3-amino-1,2-propanediol was applied as the linker between the phosphodiester bridges. Two sets of DNA duplexes were prepared. One set carried the chromophore in an A-T environment, the second set in a G-C environment. Both were characterized by optical spectroscopy. Sequence-dependent fluorescence quenching was applied as a sensitive tool to compare the stacking interactions with respect to the chirality of the acyclic linker attachment. The results were compared to recent results from duplexes that carried the Nile Blue label in a sequentially and structurally identical context, except for the opposite chirality of the linker ((S-3-amino-1,2-propandiol. Only minor, negligible differences were observed. Melting temperatures, UV–vis absorption spectra together with fluorescence quenching data indicate that Nile Blue stacks perfectly between the adjacent base pairs regardless of whether it has been attached via an S- or R-configured linker. This result was supported by geometrically optimized DNA models.

  8. Polyhydroxyalkanoate granules quantification in mixed microbial cultures using image analysis: Sudan Black B versus Nile Blue A staining.

    Science.gov (United States)

    Mesquita, Daniela P; Amaral, A Luís; Leal, Cristiano; Oehmen, Adrian; Reis, Maria A M; Ferreira, Eugénio C

    2015-03-20

    Polyhydroxyalkanoates (PHA) can be produced and intracellularly accumulated as inclusions by mixed microbial cultures (MMC) for bioplastic production and in enhanced biological phosphorus removal (EBPR) systems. Classical methods for PHA quantification use a digestion step prior to chromatography analysis, rendering them labor intensive and time-consuming. The present work investigates the use of two quantitative image analysis (QIA) procedures specifically developed for PHA inclusions identification and quantification. MMC obtained from an EBPR system were visualized by bright-field and fluorescence microscopy for PHA inclusions detection, upon Sudan Black B (SBB) and Nile Blue A (NBA) staining, respectively. The captured color images were processed by QIA techniques and the image analysis data were further treated using multivariate statistical analysis. Partial least squares (PLS) regression coefficients of 0.90 and 0.86 were obtained between QIA parameters and PHA concentrations using SBB and NBA, respectively. It was found that both staining procedures might be seen as alternative methodologies to classical PHA determination. PMID:25732579

  9. Value versus Accuracy: application of seasonal forecasts to a hydro-economic optimization model for the Sudanese Blue Nile

    Science.gov (United States)

    Satti, S.; Zaitchik, B. F.; Siddiqui, S.; Badr, H. S.; Shukla, S.; Peters-Lidard, C. D.

    2015-12-01

    The unpredictable nature of precipitation within the East African (EA) region makes it one of the most vulnerable, food insecure regions in the world. There is a vital need for forecasts to inform decision makers, both local and regional, and to help formulate the region's climate change adaptation strategies. Here, we present a suite of different seasonal forecast models, both statistical and dynamical, for the EA region. Objective regionalization is performed for EA on the basis of interannual variability in precipitation in both observations and models. This regionalization is applied as the basis for calculating a number of standard skill scores to evaluate each model's forecast accuracy. A dynamically linked Land Surface Model (LSM) is then applied to determine forecasted flows, which drive the Sudanese Hydroeconomic Optimization Model (SHOM). SHOM combines hydrologic, agronomic and economic inputs to determine the optimal decisions that maximize economic benefits along the Sudanese Blue Nile. This modeling sequence is designed to derive the potential added value of information of each forecasting model to agriculture and hydropower management. A rank of each model's forecasting skill score along with its added value of information is analyzed in order compare the performance of each forecast. This research aims to improve understanding of how characteristics of accuracy, lead time, and uncertainty of seasonal forecasts influence their utility to water resources decision makers who utilize them.

  10. Estimation of Some Bio-Physical Indicators for Sustainable Crop Production in the Eastern Nile Basin of Sudan Using Landsat-8 Imagery and SEBAL Model

    Science.gov (United States)

    Guma Biro Turk, Khalid

    2016-07-01

    Crop production under modern irrigation systems require unique management at field level and hence better utilization of agricultural inputs and water resources. This study aims to make use of remote sensing (RS) data and the surface energy balance algorithm for land (SEBAL) to improve the on-farm management. The study area is located in the Eastern part of the Blue Nile River about 60 km south of Khartoum, Sudan. Landsat-8 data were used to estimate a number of bio-physical indicators during the growing season of the year 2014/2015. Accordingly, in-situ weather data and SEBAL model were applied to calculate: the reference (ET0), actual (ETa) and potential (ETp) evapotranspiration, soil moisture (SM), crop factor (kc), nitrogen (N), biomass production (BP) and crop water productivity (CWP). Results revealed that ET0 showed steady variation throughout the year, varying from 5 to 7 mm/day. However, ETa and ETp showed clear temporal variation attributed to frequent cutting of the alfalfa, almost monthly. The BP of the alfalfa was observed to be high when there is no cutting activates were made before the image acquisition date. Nevertheless the CWP trends are following the biomass production ones, low when there is no biomass and high when the biomass is high. The application of SEBAL model within the study area using the Landsat-8 imagery indicates that it's possible to produce field-based bio-physical indicators, which can be useful in monitoring and managing the field during the growing season. However, a cross-calibration with the in-situ data should be considered in order to maintain the spatial variability within the field. Keywords: Bio-physical Indicators; Remote Sensing; SEBAL; Landsat-8; Eastern Nile Basin

  11. A preliminary site response in the Nile delta basin (Egypt) using microtremor H/V spectral ratio

    International Nuclear Information System (INIS)

    Complete text of publication follows. For understanding the behavior of ground motion in the Nile Delta to mitigate the earthquake disasters the site effects are determined. The H/V spectral ratio technique as a low cost method is used. The microtremor (background noise) measurements are carried out at 24 sites distributed at the Nile Delta provinces. The obtained fundamental frequency values ranges between 0.821 and 2 Hz in all sites except at sites 15 and 18 which reveal frequency of 8.2 and 9.2 respectively. The low values represent thick sedimentary section and the high values illustrate an impedance contrast of soft sediments at shallow depth. Some sites demonstrate two peaks one at the low frequency and the other at the higher frequency. The preliminary evaluation of site effects at the Nile Delta basin demonstrates depth heterogeneity in the sedimentary section. The maximum value of ground motion amplification was found to be 5.1 at the fundamental frequency 1.3 Hz at site 22 (Demietta). The results demonstrate that the central part of the Delta is thicker than the eastern and western parts.

  12. Development and metabolism of the city of Khartoum (Republic of Sudan: spatial designing of the coastal territory of the Blue and White Nile

    Directory of Open Access Journals (Sweden)

    Shakurov Ilhomjeon

    2016-01-01

    Full Text Available The given article reveals the development of the metabolism of the city of Khartoum, the problems of influence on the microclimate improvement elements built up coastal territory of the Blue and White Nile in Khartoum. The study shows the microclimate formation factors of Khartoum, gives an assessment of the modern state of the microclimate of the coastal zone and its changes. The article indicates that, depending on the nature of use and planning organization of coastal territories microclimatic influence of water areas can propagate over appreciable distances to the city or limitation depth in a narrow strip along the coast. In urban areas the air temperature is considerably higher and the humidity is lower than in the coastal area especially in summer, this is due to differences in physical properties of water and land. Water has a higher heat capacity, high reflectivity, the wind speed increases and increasing the humidity of air masses passing over it. Thus, in order to improve microclimatic and hygienic conditions of coastal territories in Khartoum there is the need to use the favorable impact of the Blue and White Nile.

  13. Identification and mapping of soil erosion areas in the Blue Nile-Eastern Sudan using multispectral ASTER and MODIS satellite data and the SRTM elevation model

    Science.gov (United States)

    El Haj Tahir, M.; Kääb, A.; Xu, C.-Y.

    2010-01-01

    This paper is part of a set of studies to evaluate the spatial and temporal variability of soil water in terms of natural as well as land-use changes as fundamental factors for vegetation regeneration in arid ecosystems in the Blue Nile-Sudan. The specific aim is to indicate the spatial distribution of soil erosion caused by the rains of 2006. The current study is conducted to determine whether automatic classification of multispectral Advanced Space borne Thermal Emission and Reflection Radiometer (ASTER) imagery could accurately discriminate erosion gullies. Shuttle Radar Topography Mission (SRTM) is used to orthoproject ASTER data. A maximum likelihood classifier is trained with four classes, Gullies, Flat_Land, Mountains and Water and applied to images from March and December 2006. Validation is done with field data from December and January 2006/2007, and using drainage network analysis of SRTM digital elevation model. The results allow the identification of erosion gullies and subsequent estimation of eroded area. Consequently the results were up-scaled using Moderate Resolution Imaging Spectroradiometer (MODIS) images of the same dates. Because the selected study site is representative of the wider Blue Nile province, it is expected that the approach presented could be applied to larger areas.

  14. Identification and mapping of soil erosion areas in the Blue Nile-Eastern Sudan using multispectral ASTER and MODIS satellite data and the SRTM elevation model

    Directory of Open Access Journals (Sweden)

    M. El Haj Tahir

    2010-01-01

    Full Text Available This paper is part of a set of studies to evaluate the spatial and temporal variability of soil water in terms of natural as well as land-use changes as fundamental factors for vegetation regeneration in arid ecosystems in the Blue Nile-Sudan. The specific aim is to indicate the spatial distribution of soil erosion caused by the rains of 2006. The current study is conducted to determine whether automatic classification of multispectral Advanced Space borne Thermal Emission and Reflection Radiometer (ASTER imagery could accurately discriminate erosion gullies. Shuttle Radar Topography Mission (SRTM is used to orthoproject ASTER data. A maximum likelihood classifier is trained with four classes, Gullies, Flat_Land, Mountains and Water and applied to images from March and December 2006. Validation is done with field data from December and January 2006/2007, and using drainage network analysis of SRTM digital elevation model. The results allow the identification of erosion gullies and subsequent estimation of eroded area. Consequently the results were up-scaled using Moderate Resolution Imaging Spectroradiometer (MODIS images of the same dates. Because the selected study site is representative of the wider Blue Nile province, it is expected that the approach presented could be applied to larger areas.

  15. From the Mountains of the Moon to the Grand Renaissance: misinformation, disinformation and, finally, information for cooperation in the Nile River basin

    Science.gov (United States)

    Zaitchik, B. F.; Habib, S.; Anderson, M. C.; Ozdogan, M.

    2012-12-01

    The Nile River basin is shared by 11 nations and approximately 200 million people. Eight of the riparian States are defined as Least Developed Countries by the United Nations, and about 50% of the total basin population lives below the international poverty line. In addition, eight of the eleven countries have experienced internal or external wars in the past 20 years, six are predicted to be water scarce by 2025, and, at present, major water resource development projects are moving forward in the absence of a fully recognized basin-wide water sharing agreement. Nevertheless, the Nile basin presents remarkable opportunities for transboundary water cooperation, and today—notwithstanding significant substantive and perceived disagreements between stakeholders in the basin—this cooperation is beginning to be realized in topics ranging from flood early warning to hydropower optimization to regional food security. This presentation will provide an overview of historic and present challenges and opportunities for transboundary water management in the Nile basin and will present several case studies in which improved hydroclimatic information and communication systems are currently laying the groundwork for advanced cooperation. In this context climate change acts as both stress and motivator. On one hand, non-stationary hydrology is expected to tax water resources in the basin, and it undermines confidence in conventionally formulated water sharing agreements. On the other, non-stationarity is increasingly understood to be an exogenous threat to regional food and water security that will require informed, flexible cooperation between riparian states.

  16. Earth Observation Based Assessment of the Water Production and Water Consumption of Nile Basin Agro-Ecosystems

    Directory of Open Access Journals (Sweden)

    Wim G.M. Bastiaanssen

    2014-10-01

    Full Text Available The increasing competition for water resources requires a better understanding of flows, fluxes, stocks, and the services and benefits related to water consumption. This paper explains how public domain Earth Observation data based on Moderate Resolution Imaging Spectroradiometer (MODIS, Second Generation Meteosat (MSG, Tropical Rainfall Measurement Mission (TRMM and various altimeter measurements can be used to estimate net water production (rainfall (P > evapotranspiration (ET and net water consumption (ET > P of Nile Basin agro-ecosystems. Rainfall data from TRMM and the Famine Early Warning System Network (FEWS-NET RainFall Estimates (RFE products were used in conjunction with actual evapotranspiration from the Operational Simplified Surface Energy Balance (SSEBop and ETLook models. Water flows laterally between net water production and net water consumption areas as a result of runoff and withdrawals. This lateral flow between the 15 sub-basins of the Nile was estimated, and partitioned into stream flow and non-stream flow using the discharge data. A series of essential water metrics necessary for successful integrated water management are explained and computed. Net water withdrawal estimates (natural and humanly instigated were assumed to be the difference between net rainfall (Pnet and actual evapotranspiration (ET and some first estimates of withdrawals—without flow meters—are provided. Groundwater-dependent ecosystems withdraw large volumes of groundwater, which exceed water withdrawals for the irrigation sector. There is a strong need for the development of more open-access Earth Observation databases, especially for information related to actual ET. The fluxes, flows and storage changes presented form the basis for a global framework to describe monthly and annual water accounts in ungauged river basins.

  17. Assessing the impacts of climate change on river basin management: A new method with application to the Nile River

    Science.gov (United States)

    Tidwell, Amy C.

    A framework is developed for the assessment of climate change impacts on water resources systems. The applied techniques include: quantifying global climate model (GCM) skill over a range of time scales; developing future climate scenarios based on GCM data that are found to skillfully represent the observed climate over an historical baseline period; and using the climate scenarios together with hydrologic and water resources models to make assessments of the potential impacts and implications of climate change on water resources systems. A statistical analysis of GCM skill in East Africa shows that temperature is well represented in the GCMs at monthly to annual time scales. Precipitation is found to be much less reliable in the models and shows skill in fewer seasons and nodes than temperature. Eight climate scenarios, stemming from three global climate models and two atmospheric emissions scenarios, project temperature increases between 2 and 5° Celsius by the year 2080. Precipitation projections vary widely across models as well as regionally. The scenarios project changes in precipitation from -38% to +42%. The climate change impact methodology is applied to the Nile River Basin. It is shown that, in spite of widely varying precipitation projections, the major sub-basins of the Nile River will experience decreases in watershed runoff under all eight climate scenarios. Detailed water resources models are employed to assess the system wide response to the climate-induced hydrologic changes. The assessments indicate that water supply deficits will emerge by 2030 and continue to grow in frequency and magnitude by 2080. Additional impacts include reservoir depletion and reduced hydropower generation. An assessment of the river system response to basin development projects, including additional water storage and wetlands water conservation, indicates that adverse climate impacts may be mitigated for 30 to 40 years. The assessments demonstrate the relevance of

  18. Spatio-Temporal Identification of Areas Suitable for West Nile Disease in the Mediterranean Basin and Central Europe.

    Directory of Open Access Journals (Sweden)

    Annamaria Conte

    Full Text Available West Nile virus (WNV is a mosquito-transmitted Flavivirus belonging to the Japanese encephalitis antigenic complex of the Flaviviridae family. Its spread in the Mediterranean basin and the Balkans poses a significant risk to human health and forces public health officials to constantly monitor the virus transmission to ensure prompt application of preventive measures. In this context, predictive tools indicating the areas and periods at major risk of WNV transmission are of paramount importance. Spatial analysis approaches, which use environmental and climatic variables to find suitable habitats for WNV spread, can enhance predictive techniques. Using the Mahalanobis Distance statistic, areas ecologically most suitable for sustaining WNV transmission were identified in the Mediterranean basin and Central Europe. About 270 human and equine clinical cases notified in Italy, Greece, Portugal, Morocco, and Tunisia, between 2008 and 2012, have been considered. The environmental variables included in the model were altitude, slope, night time Land Surface Temperature, Normalized Difference Vegetation Index, Enhanced Vegetation Index, and daily temperature range. Seasonality of mosquito population has been modelled and included in the analyses to produce monthly maps of suitable areas for West Nile Disease. Between May and July, the most suitable areas are located in Tunisia, Libya, Egypt, and North Cyprus. Summer/Autumn months, particularly between August and October, characterize the suitability in Italy, France, Spain, the Balkan countries, Morocco, North Tunisia, the Mediterranean coast of Africa, and the Middle East. The persistence of suitable conditions in December is confined to the coastal areas of Morocco, Tunisia, Libya, Egypt, and Israel.

  19. Predictive Modeling of West Nile Virus Transmission Risk in the Mediterranean Basin: How Far from Landing?

    OpenAIRE

    Véronique Chevalier; Annelise Tran; Benoit Durand

    2013-01-01

    The impact on human and horse health of West Nile fever (WNF) recently and dramatically increased in Europe and neighboring countries. Involving several mosquito and wild bird species, WNF epidemiology is complex. Despite the implementation of surveillance systems in several countries of concern, and due to a lack of knowledge, outbreak occurrence remains unpredictable. Statistical models may help identifying transmission risk factors. When spatialized, they provide tools to identify areas th...

  20. Hydrologic interconnection between the volcanic aquifer and springs, Lake Tana basin on the Upper Blue Nile

    Science.gov (United States)

    Nigate, Fenta; Van Camp, Marc; Kebede, Seifu; Walraevens, Kristine

    2016-09-01

    Hydrochemical and stable isotope (δ18O, δ2H) data were used to identify the recharge sources of major springs and the hydraulic interconnection between the volcanic aquifer and springs in the Gilgel Abay catchment and adjacent areas. The hydrochemical data analysis showed that all water samples of springs and shallow wells have freshwater chemistry, Casbnd HCO3 to Casbnd Mgsbnd HCO3 types. This is mainly controlled by dissolution/hydrolysis of silicate minerals. The analyzed stable isotope data indicate that springs water, except Dengel Mesk, Kurt Bahir and Bility springs, and well waters, except Dangila well, fall close to the LMWL. This clearly shows that the infiltrated rainwater did not undergo much evaporation and δ18O values for spring water and groundwater are nearly equal to the value of Ethiopian summer rainfall, which is -2.5‰. Therefore, generally both stable isotope and hydrochemical data show the recharge source to springs and shallow groundwater is primarily from precipitation. Furthermore, data suggest that rock-water interaction has remained relatively limited, pointing to relatively short residence times, and local recharge rather than regional recharge.

  1. Economic and institutional incentives for managing the Ethiopean highlands of the Upper Blue Nile Basin

    DEFF Research Database (Denmark)

    Kassahun, Habtamu Tilahun; Jacobsen, Jette Bredahl

    2015-01-01

    of grazing land reform, and an additional extension service. Thus, we address farmers’ combined choice of management of private and communal lands. We use a latent class model with attribute non-attendance for one class to accommodate the preferences of farmers who always select the status quo option without...... making a trade-off for experimentally designed policy attributes. Moreover, we estimate individual specific and socio-spatial group specific preferences across 90 units. Farmers’ preference within the same socio-spatial unit is fairly homogeneous. Apart from the non-attendance class, the study reveals...... two classes. One class, which is probably dominated by literate farmers and farmers who have easy credit access, is willing to contribute more labour and requires fewer subsidies than the other class. Furthermore, the two groups have opposite viewpoints on management (semi-privatisation of common land...

  2. Hydrogeochemistry and environmental isotope investigations of the Nile basin water in Sohag district, Upper Egypt

    International Nuclear Information System (INIS)

    This paper discusses the results of environmental isotopes and major chemical data for twenty-eight selected water samples representative of the Nile water in Sohag district. The major ion chemistry is used to tabulate the water types for the aquifer and to review the source of salinity. The stable isotopes 18O and 2H are used to investigate the groundwater origin and the possible recharge sources. The radioactive isotope tritium is applied to assess the approximate residence time of groundwater in the aquifer

  3. LIS-HYMAP coupled Hydrological Modeling in the Nile River Basin and the Greater Horn of Africa

    Science.gov (United States)

    Jung, H. C.; Getirana, A.; Policelli, F. S.

    2015-12-01

    Water scarcity and resources in Africa have been exacerbated by periodic droughts and floods. However, few studies show the quantitative analysis of water balance or basin-scale hydrological modeling in Northeast Africa. The NASA Land Information System (LIS) is implemented to simulate land surface processes in the Nile River Basin and the Greater Horn of Africa. In this context, the Noah land surface model (LSM) and the Hydrological Modeling and Analysis Platform (HYMAP) are used to reproduce the water budget and surface water (rivers and floodplains) dynamics in that region. The Global Data Assimilation System (GDAS) meteorological dataset is used to force the system . Due to the unavailability of recent ground-based observations, satellite data are considered to evaluate first model outputs. Water levels at 10 Envisat virtual stations and water discharges at a gauging station are used to provide model performance coefficients (e.g. Nash-Sutcliffe, delay index, relative error). We also compare the spatial and temporal variations of flooded areas from the model with the Global Inundation Extent from Multi-Satellites (GIEMS) and the Alaska Satellite Facility (ASF)'s MEaSUREs Wetland data. Finally, we estimate surface water storage variations using a hypsographic curve approach with Shuttle Radar Topography Mission (SRTM) topographic data and evaluate the model-derived water storage changes in both river and floodplain. This study demonstrates the feasibility of using LIS-HYMAP coupled modeling to support seasonal forecast methods for prediction of decision-relevant metrics of hydrologic extremes.

  4. Assessment of spatial and temporal patterns of green and blue water flows in inland river basins in Northwest China

    Directory of Open Access Journals (Sweden)

    C. F. Zang

    2012-03-01

    Full Text Available In arid and semi-arid regions freshwater resources have become scarcer with increasing demands from socio-economic development and population growth. Until recently, water research and management in these has mainly focused on blue water but ignored green water. Here we report on spatial and temporal patterns of both blue and green water flows simulated by the Soil and Water Assessment Tool (SWAT for the Heihe river basin, the second largest inland river basin in Northwest China. Calibration and validation at two hydrological stations show good performance of the SWAT model in modelling hydrological processes. The total green and blue water flows were 22.09 billion m3 in the 2000s for the Heihe river basin. Blue water flows are larger in upstream sub-basins than in downstream sub-basins mainly due to high precipitation and large areas of glaciers in upstream. Green water flows are distributed more homogeneously among different sub-basins. The green water coefficient was 88.0% in the 2000s for the entire river basin, varying from around 80–90% in up- and mid-stream sub-basins to above 95% in downstream sub-basins. This is much higher than reported green water coefficient in many other river basins. The spatial patterns of green water coefficient were closely linked to dominant land covers (e.g. glaciers in upstream and desert in downstream and climate conditions (e.g. high precipitation in upstream and low precipitation in downstream. There are no clear consistent historical trends of change in green and blue water flows and green water coefficient at both the river basin and sub-basin levels. This study provides insights into green and blue water endowments for the entire Heihe river basin at sub-basin level. The results are helpful for formulating reasonable water policies to improve water resources management in the inland river basins of China.

  5. A GRACE-Streamflow Land Surface Model Calibration Approach for Improved Baseflow and Water Table Simulations over the Highly Managed Upper-Nile Basin of East Africa

    Science.gov (United States)

    Nanteza, J.; Lo, M. H.; Wu, R. J.; Thomas, B. F.; Famiglietti, J. S.

    2015-12-01

    Land surface models (LSMs) are useful tools for understanding behaviors of land hydrologic variables at different time and spatial scales. LSM outputs, however, are marked with great uncertainties resulting from the simplified assumptions on the parameterization and processes of the land surface and a poor representation of both the natural and anthropogenic controls on the system. The Upper-Nile basin, over Uganda, Kenya and Tanzania, is one region that is characteristic of significant human controls on streamflow, including Lake Victoria releases. The river Nile flow from Lake Victoria follows apriori rating curves that are not simulated by LSMs. Apart from management practices; the huge storage volume of Lake Victoria also modifies the seasonal characteristics of the Upper-Nile discharge, creating small seasonal variations in stream flow. In this study we calibrate several critical parameters in the Community Land Model (CLM.v4) in a multiobjective framework using total water storage anomalies (∆TWS) from GRACE, observed total runoff (Q) and estimated baseflow (BF) over the Upper-Nile basin. The goal is to improve the CLM parameters so that the model simulates the agreed curve (apriori) streamflow and baseflow with a better accuracy. We demonstrate the significance of improved parametrization by comparing model results of ∆TWS, Q and BF with a combination of insitu and estimated observations. Preliminary results based on RMSE statistics show that with calibration, simulations of ∆TWS, Q and BF achieve higher performance. Further, an improvement in the model's capacity to simulate the water table depth is also evident with the calibration. Such results provide a basis for using CLM for other hydrologic experiments that could guide water resources management in this highly managed basin.

  6. Assessment of climate change impact on hydrological extremes in two source regions of the Nile River Basin

    Directory of Open Access Journals (Sweden)

    M. T. Taye

    2011-01-01

    Full Text Available The potential impact of climate change was investigated on the hydrological extremes of Nyando River and Lake Tana catchments, which are located in two source regions of the Nile River basin. Climate change scenarios were developed for rainfall and potential evapotranspiration (ETo, considering 17 General Circulation Model (GCM simulations to better understand the range of possible future change. They were constructed by transferring the extracted climate change signals to the observed series using a frequency perturbation downscaling approach, which accounts for the changes in rainfall extremes. Projected changes under two future SRES emission scenarios A1B and B1 for the 2050s were considered. Two conceptual hydrological models were calibrated and used for the impact assessment. Their difference in simulating the flows under future climate scenarios was also investigated.

    The results reveal increasing mean runoff and extreme peak flows for Nyando catchment for the 2050s while unclear trend is observed for Lake Tana catchment for mean volumes and high/low flows. The hydrological models for Lake Tana catchment, however, performed better in simulating the hydrological regimes than for Nyando, which obviously also induces a difference in the reliability of the extreme future projections for both catchments. The unclear impact result for Lake Tana catchment implies that the GCM uncertainty is more important for explaining the unclear trend than the hydrological models uncertainty. Nevertheless, to have a better understanding of future impact, hydrological models need to be verified for their credibility of simulating extreme flows.

  7. Shifting sediment sources in the world's longest river: A strontium isotope record for the Holocene Nile

    Science.gov (United States)

    Woodward, Jamie; Macklin, Mark; Fielding, Laura; Millar, Ian; Spencer, Neal; Welsby, Derek; Williams, Martin

    2015-12-01

    We have reconstructed long-term shifts in catchment sediment sources by analysing, for the first time, the strontium (Sr) and neodymium (Nd) isotope composition of dated floodplain deposits in the Desert Nile. The sediment load of the Nile has been dominated by material from the Ethiopian Highlands for much of the Holocene, but tributary wadis and aeolian sediments in Sudan and Egypt have also made major contributions to valley floor sedimentation. The importance of these sources has shifted dramatically in response to global climate changes. During the African Humid Period, before c. 4.5 ka, when stronger boreal summer insolation produced much higher rainfall across North Africa, the Nile floodplain in northern Sudan shows a tributary wadi input of 40-50%. Thousands of tributary wadis were active at this time along the full length of the Saharan Nile in Egypt and Sudan. As the climate became drier after 4.5 ka, the valley floor shows an abrupt fall in wadi inputs and a stronger Blue Nile/Atbara contribution. In the arid New Kingdom and later periods, in palaeochannel fills on the margins of the valley floor, aeolian sediments replace wadi inputs as the most important secondary contributor to floodplain sedimentation. Our sediment source data do not show a measurable contribution from the White Nile to the floodplain deposits of northern Sudan over the last 8500 years. This can be explained by the distinctive hydrology and sediment delivery dynamics of the upper Nile basin. High strontium isotope ratios observed in delta and offshore records - that were previously ascribed to a stronger White Nile input during the African Humid Period - may have to be at least partly reassessed. Our floodplain Sr records also have major implications for bioarchaeologists who carry out Sr isotope-based investigations of ancient human remains in the Nile Valley because the isotopic signature of Nile floodplain deposits has shifted significantly over time.

  8. Ocean-color remote sensing of the Nile delta shelf and SE Levantine basin and possible linkage to some mesoscale circulation features and Nile river run-off

    Science.gov (United States)

    Moufaddal, Wahid; Lavender, Samantha

    To date, and despite the passage of more than 30 years since the launch of the first satellite based ocean-color sensor, no systematic study of the variability of chlorophyll in the Egyptian Mediterranean coast off the Nile delta has been undertaken using this kind of data. Meantime, available in-situ measurements on chlorophyll and other nutrient parameters along this coast are indeed very modest and scarce. The lack of data has in turn created a large gap in our knowledge on the biogeochemical characteristics of the coastal water and impacts of the Aswan High Dam and other land-use changes on the marine ecosystems and nutrient budget in the Nile delta shelf and the SE Mediterranean. The present study aims to fill part of this gap through application of ocean-color remote sensing and satellite retrieval of phytoplankton chlorophyll. For this purpose a 10-year (1997-2006) monthly satellite dataset from ESA Globcolour project (an ESA Data User Element project: http://www.globcolour.info) was retrieved and subjected to time-series analysis. Results of this analysis revealed that the oceanic and coastal parts off the Nile delta coast and SE Mediterranean manifest from time to time some of the most interesting and dynamical marine features including meso-scale gyres, coastal filaments, localized algal blooms and higher concentration of phytoplankton chlorophyll. These features together with certain physical pro-cesses and surface run-off from Nile mouthes and other land-based sources were found to exert pronounced effects on the nutrient supply and quality of the coastal and oceanic surface waters in this region. Results reveled also that there has been a general upward trend in concentration of surface chlorophyll during the 10-year period from 1997 to 2006 with a coincident rise of the coastal fisheries implying that improvement of nutrient supply is most likely responsible for this rise. Results confirmed also shift of the Nile phytoplankton bloom in space and time

  9. Orbital forcing of glacial/interglacial variations in chemical weathering within the White Nile basin: stable-isotope and biomarker evidence from Lakes Victoria and Edward

    Science.gov (United States)

    Cockerton, Helen E.; Alayne Street-Perrott, F.; Barker, Philip A.; Leng, Melanie J.; Sloane, Hilary J.; Horstwood, Matthew S. A.; Snelling, Andrea

    2014-05-01

    The continental Si cycle on Quaternary time scales has been largely neglected. Emphasis has been placed on long-term geochemical processes of silicate-rock weathering and the resulting drawdown of atmospheric CO2, rather than on shorter-term biogenic processes occurring along the land-ocean continuum. Si-accumulating plants (notably tropical rainforest hardwoods, savanna and wetland grasses, and Papyrus) and aquatic organisms (such as diatoms and sponges in lakes, rivers and swamps) have the potential to take up, store and recycle significant amounts of Si, thereby modifying the riverine flux of Si to the oceans, the productivity of siliceous marine organisms and the rate of atmospheric CO2 drawdown on an orbital time scale. The main aim of this study was to investigate spatial and temporal patterns of Si cycling along the Nile system during the last 20ka BP. Utilising sediment cores from Lakes Victoria and Edward, coupled measurements of stable Si and O isotopes on cleaned diatom separates were employed to reconstruct millennial-scale variations in biotic Si cycling and palaeohydrology, respectively. Abundance ratios of lipid biomarkers (n-alkanes) were used to track major changes in terrestrial and aquatic ecosystems. The results have been interpreted in the light of multi-isotope analyses (2H,18O,30Si) of modern water samples collected along the courses of the modern White and Blue Niles during both wet- and dry-season conditions. During drier intervals (the Last Glacial Maximum and the late Holocene: high 18Odiatom), Si cycling was greatly reduced. Diminished vegetation cover, reduced biotic rock weathering, a declining soil stock of amorphous silica (ASi) and decreased runoff resulted in reduced dissolved silica (DSi) supply to the lakes in relation to aquatic demand (high 30Sidiatom). In contrast, enhanced monsoon rainfall (low 18Odiatom) during the early to mid-Holocene promoted a substantial increase in terrestrial biomass within the White Nile headwaters

  10. Institutional and legal arrangements in the Nile river basin: suggestions to improve the current situation toward adaptive integrated water resources management.

    Science.gov (United States)

    Abdalla, Khalid Mohamed El Hassan

    2008-01-01

    A comparative study was conducted in this work in order to investigate the current situation in the Nile river basin (NRB) regarding the institutional and legal arrangements needed to support the adaptive integrated water resources management (AIWRM) strategy. Two similar river basins were selected to achieve this comparison and to introduce suggestions to reform the current situation in the basin. Before that, the ideal situation is investigated to be as a yardstick for the desired situation. The study indicated that the necessary AIWRM criteria may include regulatory as well as implementation organizations that support shared-vision reaching with its all necessary features (cooperation, stakeholders' participation, subsidiarity, and information and knowledge exchange). Thus the main features of the desired situations regarding AIWRM in river basins are stakeholders' participation, learning-driven ability, quick response to risks and uncertainties, and finally a legal framework that could support these criteria. Although the AIWRM criteria seem to be satisfied in NRB, the basin lacks the necessary regulatory institutions as well as the legal framework. According to this, this study recommends to reform the current situation in NRB by creating regulator institutions (policy and decision making level) as well a legal framework to legitimate them.

  11. Multi-objective regionalisation for lake level simulation, the case of Lake Tana in the Upper Blue Nile, Ethiopia

    Directory of Open Access Journals (Sweden)

    T. H. M. Rientjes

    2010-09-01

    Full Text Available The aim in this study is to simulate lake levels of Lake Tana by solving the water balance at daily time step. Since 42% of the basin is ungauged regionalisation procedures are applied. We examine the predictive capability of a regionalisation approach that combines multi-objective calibration of a simple conceptual model and multi regression analyses to establish relations between model parameters and catchment characteristics. Recently few studies are presented on lake level simulation of Lake Tana. In these studies the water balance of the lake is closed by estimation of runoff contributions from ungauged catchments. Studies partly relied on simple ad-hoc procedures of area comparison to estimate runoff from ungauged catchments. In this study a regional model is developed that relies on principles of similarity of catchments. For runoff modelling the HVB-96 model is selected while multi-objective model calibration is by a Monte Carlo procedure.

    Assessment of the lake water balance was established by comparing measured to estimated lake levels. Results of daily lake level simulation show a water balance closure term of 85 mm and a relative volume error of 2.17%. Results show runoff from ungauged catchments of 527 mm per year for the simulation period 1994 to 2003 that is approximately 30% of Lake Tana stream flow inflow. Compared to previous works this closure term is smallest.

  12. Multi-objective regionalisation for lake level simulation, the case of Lake Tana in the Upper Blue Nile, Ethiopia

    Science.gov (United States)

    Rientjes, T. H. M.; Perera, B. U. J.; Haile, A. T.; Reggiani, P.

    2010-09-01

    The aim in this study is to simulate lake levels of Lake Tana by solving the water balance at daily time step. Since 42% of the basin is ungauged regionalisation procedures are applied. We examine the predictive capability of a regionalisation approach that combines multi-objective calibration of a simple conceptual model and multi regression analyses to establish relations between model parameters and catchment characteristics. Recently few studies are presented on lake level simulation of Lake Tana. In these studies the water balance of the lake is closed by estimation of runoff contributions from ungauged catchments. Studies partly relied on simple ad-hoc procedures of area comparison to estimate runoff from ungauged catchments. In this study a regional model is developed that relies on principles of similarity of catchments. For runoff modelling the HVB-96 model is selected while multi-objective model calibration is by a Monte Carlo procedure. Assessment of the lake water balance was established by comparing measured to estimated lake levels. Results of daily lake level simulation show a water balance closure term of 85 mm and a relative volume error of 2.17%. Results show runoff from ungauged catchments of 527 mm per year for the simulation period 1994 to 2003 that is approximately 30% of Lake Tana stream flow inflow. Compared to previous works this closure term is smallest.

  13. Regionalisation for lake level simulation – the case of Lake Tana in the Upper Blue Nile, Ethiopia

    Directory of Open Access Journals (Sweden)

    T. H. M. Rientjes

    2011-04-01

    Full Text Available In this study lake levels of Lake Tana are simulated at daily time step by solving the water balance for all inflow and outflow processes. Since nearly 62% of the Lake Tana basin area is ungauged a regionalisation procedure is applied to estimate lake inflows from ungauged catchments. The procedure combines automated multi-objective calibration of a simple conceptual model and multiple regression analyses to establish relations between model parameters and catchment characteristics.

    A relatively small number of studies are presented on Lake Tana's water balance. In most studies the water balance is solved at monthly time step and the water balance is simply closed by runoff contributions from ungauged catchments. Studies partly relied on simple ad-hoc procedures of area comparison to estimate runoff from ungauged catchments. In this study a regional model is developed that relies on principles of similarity of catchments characteristics. For runoff modelling the HBV-96 model is selected while multi-objective model calibration is by a Monte Carlo procedure. We aim to assess the closure term of Lake Tana's water balance, to assess model parameter uncertainty and to evaluate effectiveness of a multi-objective model calibration approach to make hydrological modeling results more plausible.

    For the gauged catchments, model performance is assessed by the Nash-Sutcliffe coefficient and Relative Volumetric Error and resulted in satisfactory to good performance for six, large catchments. The regional model is validated and indicated satisfactory to good performance in most cases. Results show that runoff from ungauged catchments is as large as 527 mm per year for the simulation period and amounts to approximately 30% of Lake Tana stream inflow. Results of daily lake level simulation over the simulation period 1994–2003 show a water balance closure term of 85 mm per year that accounts to 2.7% of the total lake inflow. Lake level

  14. The modern Nile sediment system: Processes and products

    Science.gov (United States)

    Garzanti, Eduardo; Andò, Sergio; Padoan, Marta; Vezzoli, Giovanni; El Kammar, Ahmed

    2015-12-01

    We trace compositional changes of Nile sediments for 7400 km, from their sources in equatorial rift highlands of Burundi and Rwanda to their sink in the Mediterranean Sea. All chemical and physical controls on sediment petrography, mineralogy and geochemistry, including weathering, grain-size, hydraulic sorting, mechanical breakdown, anthropic impact, mixing and recycling are investigated in detail. The Nile course is controlled along its entire length by the East African-Red Sea Rift. In this anorogenic setting, detritus is derived in various proportions from volcanic fields associated with tectonic extension (Anorogenic Volcanic provenance) and from igneous, metamorphic and sedimentary rocks uplifted on the rift shoulders or exposed on the craton (Continental Block provenance). The entire spectrum of such detrital signatures is displayed in the Nile catchment. Volcaniclastic Atbara sand is generated by focused erosion of the Ethiopian basaltic plateau in semiarid climate, whereas quartzose White Nile sand reflects low erosion rates, extensive weathering and sediment trapping in lakes and swamps at equatorial to subequatorial latitudes. In the main Nile, as in its main tributary the Blue Nile, suspended load is volcaniclastic, whereas feldspatho-quartzose bedload is derived largely from basement sources, with fine to medium-grained eolian sand added along the lower course. Mixing of detrital populations with different provenance and grain size is reflected in diverse violations of settling-equivalence relationships in fluvial and deltaic sediments. Sediment delivery from Sudan has been cut off after closure of the Aswan High Dam and accelerated erosion of deltaic cusps is leading to local formation of placer lags dominated by ultradense Fe-Ti-Cr oxides, but mineralogical changes caused by man's radical modification of fluvial regimes have been minor so far. In beaches of Sinai, Gaza and Israel, the Nile volcaniclastic trace gets progressively diluted by quartzose

  15. Biophysical and financial impacts of community-based gully rehabilitation in the Birr Watershed, Upper Blue Nile Basin, Ethiopia

    Science.gov (United States)

    Although erosion in the Ethiopian highlands has been occurring for thousands of years, rivers sediment concentration has increased two to three fold during the last fifty years, reducing crop and livestock production and the volume of irrigation water stored in reservoirs. Gully erosion in particula...

  16. Global water scarcity: the monthly blue water footprint compared to blue water availability for the world's major river basins

    NARCIS (Netherlands)

    Hoekstra, A.Y.; Mekonnen, M.M.

    2011-01-01

    Conventional blue water scarcity indicators suffer from four weaknesses: they measure water withdrawal instead of consumptive water use, they compare water use with actual runoff rather than natural (undepleted) runoff, they ignore environmental flow requirements and they evaluate scarcity on an ann

  17. Quaternary history of the White Nile

    Science.gov (United States)

    williams, martin

    2014-05-01

    The White Nile only joined the Blue Nile ~0.3 Ma ago. It provides much of the low water discharge to the Nile. Without this contribution, in very dry years the Nile would dry up during the winter months. Owing to its very gentle flood gradient of 1: 100,000, the White Nile has an unusually complete alluvial record. High White Nile flood levels dated by OSL are synchronous with sapropel units S8, S7, S6, S5 and S1 in the East Mediterranean, which have astronomical ages of 217, 195, 172, 124 and 8 ka, respectively. Blue Nile palaeochannels that flow into the former White Nile complete the flood record, and coincide with sapropel units S4, S3 and S2, with respective ages of 102, 81 and 55 ka. The two most recent phases of very high White Nile flow were marked by widespread flooding across the lower White Nile valley during the last interglacial and the terminal Pleistocene - the latter coinciding with the abrupt return of the summer monsoon at 14.5 ka and the synchronous onset of humid conditions across the Sahara and East Africa, which ended suddenly at 5 ka, when desiccation set in. This humid phase was not uniformly wet; nor was the late Holocene uniformly dry. High White Nile flood levels have calibrated radiocarbon ages of 14.7-13.1, 9.7-9.0, 7.9-7.6, 6.3 and 3.2-2.8 ka obtained on freshwater gastropod shells. It was during these times that the White Nile valley was occupied successively by Mesolithic, Neolithic and Meroitic societies. West of the lower White Nile shallow ponds fed by local runoff supported an abundant gastropod fauna between 9.9 and 7.6 ka, with peak wetness at 9.0-8.4 ka, coeval with Mesolithic barbed bone harpoon sites east of the lower White Nile. The drier intervals recorded in the White Nile valley appear to coincide with times of polar cooling and more widespread tropical aridity.

  18. Inter- and intra-annual variation of water footprint of crops and blue water scarcity in the Yellow River basin (1961-2009)

    Science.gov (United States)

    Zhuo, La; Mekonnen, Mesfin M.; Hoekstra, Arjen Y.; Wada, Yoshihide

    2016-01-01

    The Yellow River Basin (YRB), the second largest river basin of China, has experienced a booming agriculture over the past decades. But data on variability of and trends in water consumption, pollution and scarcity in the YRB are lacking. We estimate, for the first time, the inter- and intra-annual water footprint (WF) of crop production in the YRB for the period 1961-2009 and the variation of monthly scarcity of blue water (ground and surface water) for 1978-2009, by comparing the blue WF of agriculture, industry and households in the basin to the maximum sustainable level. Results show that the average overall green (from rainfall) and blue (from irrigation) WFs of crops in the period 2001-2009 were 14% and 37% larger, respectively, than in the period 1961-1970. The annual nitrogen- and phosphorus-related grey WFs (water required to assimilate pollutants) of crop production grew by factors of 24 and 36, respectively. The green-blue WF per ton of crop reduced significantly due to improved crop yields, while the grey WF increased because of the growing application of fertilizers. The ratio of blue to green WF increased during the study period resulting from the expansion of irrigated agriculture. In the period 1978-2009, the annual total blue WFs related to agriculture, industry and households varied between 19% and 52% of the basin's natural runoff. The blue WF in the YRB generally peaks around May-July, two months earlier than natural peak runoff. On average, the YRB faced moderate to severe blue water scarcity during seven months (January-July) per year. Even in the wettest month in a wet year, about half of the area of the YRB still suffered severe blue water scarcity, especially in the basin's northern part.

  19. Water footprints as an indicator for the equitable utilization of shared water resources. (Case study: Egypt and Ethiopia shared water resources in Nile Basin)

    Science.gov (United States)

    Sallam, Osama M.

    2014-12-01

    The question of "equity." is a vague and relative term in any event, criteria for equity are particularly difficult to determine in water conflicts, where international water law is ambiguous and often contradictory, and no mechanism exists to enforce principles which are agreed-upon. The aim of this study is using the water footprints as a concept to be an indicator or a measuring tool for the Equitable Utilization of shared water resources. Herein Egypt and Ethiopia water resources conflicts in Nile River Basin were selected as a case study. To achieve this study; water footprints, international virtual water flows and water footprint of national consumption of Egypt and Ethiopia has been analyzed. In this study, some indictors of equitable utilization has been gained for example; Egypt water footprint per capita is 1385 CM/yr/cap while in Ethiopia is 1167 CM/yr/cap, Egypt water footprint related to the national consumption is 95.15 BCM/yr, while in Ethiopia is 77.63 BCM/yr, and the external water footprints of Egypt is 28.5%, while in Ethiopia is 2.3% of the national consumption water footprint. The most important conclusion of this study is; natural, social, environmental and economical aspects should be taken into account when considering the water footprints as an effective measurable tool to assess the equable utilization of shared water resources, moreover the water footprints should be calculated using a real data and there is a necessity to establishing a global water footprints benchmarks for commodities as a reference.

  20. Impacts of human activities and climate variability on green and blue water flows in the Heihe River Basin in Northwest China

    Directory of Open Access Journals (Sweden)

    C. Zang

    2013-07-01

    Full Text Available Human activities and climate factors both affect the availability of water resources and the sustainability of water management. Especially in already dry regions, water has become more and more scarce with increasing requirements from growing population, economic development and diet shifts. Although progress has been made in understanding variability of runoff, the impacts of climate variability and human activities on flows of both green water (actual evapotranspiration and blue water (discharge accumulated in the river network remain less well understood. We study the spatial patterns of blue and green water flows and the impacts on them of human activities and climate variability as simulated by the Soil and Water Assessment Tool (SWAT for an inland Heihe river basin located in Northwest China. The results show that total green and blue water flow increased from 1980 to 2005, mainly as a result of climate variability (upward precipitation trends. Direct human activities did not significantly change the total green and blue water flow. However, land use change led to a transformation of 206 million m3 from green to blue water flow, while farmland irrigation expansion resulted in a transformation of 66 million m3 from blue to green water flow. The synchronous climate variability caused an increase of green water flow by 469 million m3 and an increase of blue water flow by 146 million m3 at the river basin level, while the geographical distribution showed an uneven change even with reductions of water flows in western sub-basins at midstream. The results are helpful to benchmark the water resources in the context of global change in the inland river basins in China. This study also provides a general approach to investigate the impacts of historical human activities and climate variability on green and blue water flows at the river basin level.

  1. Pollution ecology of breeding great blue herons in the Columbia Basin, Oregon and Washington

    Science.gov (United States)

    Blus, L.J.; Henny, C.J.; Kaiser, T.E.

    1980-01-01

    Approximately 40 pairs of Great Blue Herons (Ardea herodias) formerly nested in trees on or near Blalock Island about 95 km downstream from Richland, Washington, in the Columbia River (Nehls 1972 ). In conjunction with construction of the John Day Lock and Dam and before creating Lake Umatilla in 1968, large trees along the shoreline, including those in the heronry on Blalock Island, were removed except for about six cottonwood trees (Populus sp.) that were left standing near the south bank of the river (David Lenhart, pers. comm.). As a mitigation procedure, the Umatilla National Wildlife Refuge (Umatilla) was established in 1967. The herons subsequently established a secondary heronry in the six cottonwoods; 20 pairs were present in 1971 (Nehls 1972). The inundated trees died and deteriorated; only two trees with eight nests remained in 1976 (Henny and Kurtz 1978), and we found just two nests in one tree in 1978. With a decrease in traditional nesting sites, the birds nested on islands in big sagebrush (Artemisia tridentata), on channel markers in the Columbia River, and on nesting platforms constructed for Canada Geese (Branta canadensis). The purpose of this paper is to describe the breeding biology of Great Blue Herons at Umatilla and the McNary Recreation Area (McNary) in 1978 and the relationship of organochlorine residues in eggs to eggshell thickness and reproductive success. The primary reason for conducting this study was to determine if the heptachlor seed treatment that was severely affecting Canada Geese at Umatilla (Blus et al. 1979) was also a hazard to Great Blue Herons. At the same time we also investigated possible effects of other organochlorines on the herons.

  2. Nile Basin Initiative diskursiivisena areenana

    OpenAIRE

    Laitinen, Erkka Petteri

    2011-01-01

    Vain tiivistelmÀ. OpinnÀytteiden sidotut arkistokappaleet ovat luettavissa HY:n keskustakampuksen valtiotieteiden kirjastossa (Unioninkatu 35). OpinnÀytteitÀ lainataan ainoastaan mikrokortteina kirjaston kaukopalvelun vÀlityksellÀ. Abstract only. The paper copy of the whole thesis is available for reading room use at the Library of Social Sciences (Unioninkatu 35) . Microfiche copies of these theses are available for interlibrary loans. Endast avhandlingens sammandrag. Pappersexem...

  3. Assessment of undiscovered oil and gas resources of the East Coast Mesozoic basins of the Piedmont, Blue Ridge Thrust Belt, Atlantic Coastal Plain, and New England Provinces, 2011

    Science.gov (United States)

    Milici, Robert C.; Coleman, James L.; Rowan, Elisabeth L.; Cook, Troy A.; Charpentier, Ronald R.; Kirschbaum, Mark A.; Klett, Timothy R.; Pollastro, Richard M.; Schenk, Christopher J.

    2012-01-01

    During the early opening of the Atlantic Ocean in the Mesozoic Era, numerous extensional basins formed along the eastern margin of the North American continent from Florida northward to New England and parts of adjacent Canada. The basins extend generally from the offshore Atlantic continental margin westward beneath the Atlantic Coastal Plain to the Appalachian Mountains. Using a geology-based assessment method, the U.S. Geological Survey estimated a mean undiscovered natural gas resource of 3,860 billion cubic feet and a mean undiscovered natural gas liquids resource of 135 million barrels in continuous accumulations within five of the East Coast Mesozoic basins: the Deep River, Dan River-Danville, and Richmond basins, which are within the Piedmont Province of North Carolina and Virginia; the Taylorsville basin, which is almost entirely within the Atlantic Coastal Plain Province of Virginia and Maryland; and the southern part of the Newark basin (herein referred to as the South Newark basin), which is within the Blue Ridge Thrust Belt Province of New Jersey. The provinces, which contain these extensional basins, extend across parts of Georgia, South Carolina, North Carolina, Virginia, Maryland, Delaware, Pennsylvania, New Jersey, New York, Connecticut, and Massachusetts.

  4. The question of Sudan: a hydroeconomic optimization model for the Sudanese Nile

    Science.gov (United States)

    Satti, S.; Zaitchik, B.; Siddiqui, S.

    2014-10-01

    The effects of development and the uncertainty of a changing climate in East Africa pose myriad challenges for water managers along the Blue Nile. Sudan's large irrigation potential, hydroelectric dams, and prime location within the basin mean that Sudan's water management decisions will have great social, economic and political implications within the region. At the same time, Sudan's water use options are constrained by tradeoffs between upstream irrigation developments and downstream hydropower facilities as well as by the country's commitments under existing or future transboundary water sharing agreements. Here, we present a model that can be applied to evaluate optimal allocation of surface water resources to irrigation and hydropower in the Sudanese portion of the Blue Nile. Hydrologic inputs are combined with agronomic and economic inputs to formulate an optimization model within the General Algebraic Modeling System (GAMS). A sensitivity analysis is performed by testing model response to a range of economic conditions and to changes in the volume and timing of hydrologic flows. Results indicate that changing hydroclimate inputs have the capacity to greatly influence the productivity of Sudan's water resources infrastructure. Results also show that the economically optimal volume of water consumption, and thus the importance of existing treaty constraints, is sensitive to the perceived value of agriculture relative to electricity as well as to changing hydrological conditions.

  5. What's West Nile Virus?

    Science.gov (United States)

    ... Help White House Lunch Recipes What's West Nile Virus? KidsHealth > For Kids > What's West Nile Virus? Print A A A Text Size en español ¿Qué es el Virus del Nilo Occidental? What exactly is the West ...

  6. FAQ: General Questions about West Nile Virus

    Science.gov (United States)

    ... Public Service Videos General Questions About West Nile Virus Recommend on Facebook Tweet Share Compartir On this ... West Nile virus cases? What is West Nile virus? West Nile virus is an arthropod-borne virus ( ...

  7. Rainfall variability and estimation for hydrologic modeling : a remote sensing based study at the source basin of the Upper Blue Nile River

    NARCIS (Netherlands)

    Haile, Alemseged Tamiru

    2010-01-01

    Rainfall is one of the meteorological forcing terms in hydrologic modelling and therefore its spatial variability in coverage, frequency and intensity affects simulation results. Rainfall variability in particular under the effect of orography adjacent to a large water body is not fully explored. Su

  8. Tracking Nile Delta vulnerability to Holocene change.

    Directory of Open Access Journals (Sweden)

    Nick Marriner

    Full Text Available Understanding deltaic resilience in the face of Holocene climate change and human impacts is an important challenge for the earth sciences in characterizing the full range of present and future wetland responses to global warming. Here, we report an 8000-year mass balance record from the Nile Delta to reconstruct when and how this sedimentary basin has responded to past hydrological shifts. In a global Holocene context, the long-term decrease in Nile Delta accretion rates is consistent with insolation-driven changes in the 'monsoon pacemaker', attested throughout the mid-latitude tropics. Following the early to mid-Holocene growth of the Nile's deltaic plain, sediment losses and pronounced erosion are first recorded after ~4000 years ago, the corollaries of falling sediment supply and an intensification of anthropogenic impacts from the Pharaonic period onwards. Against the backcloth of the Saharan 'depeopling', reduced river flow underpinned by a weakening of monsoonal precipitation appears to have been particularly conducive to the expansion of human activities on the delta by exposing productive floodplain lands for occupation and irrigation agriculture. The reconstruction suggests that the Nile Delta has a particularly long history of vulnerability to extreme events (e.g. floods and storms and sea-level rise, although the present sediment-starved system does not have a direct Holocene analogue. This study highlights the importance of the world's deltas as sensitive archives to investigate Holocene geosystem responses to climate change, risks and hazards, and societal interaction.

  9. Leaf curl diseases of two solanaceous species in Southwest Arabia are caused by a monopartite begomovirus evolutionarily most closely related to a species from the Nile Basin and unique suite of betasatellites

    KAUST Repository

    Idris, Ali

    2012-10-01

    The complete genome of 2780 bases was amplified using rolling circle amplification, and cloned, and sequenced for two distinct strains of the monopartite begomovirus Tomato leaf curl Sudan virus (ToLCSDV). The two strains shared 86-91% identity with the previously described ToLCSDV from the Nile Basin, and 90-91% identity with one another. One strain was cloned from symptomatic tomato plants from Tihamah (ToLCSDV-YE[YE:Tih:05]) while the other was cloned from symptomatic tobacco plants collected from Wadi Hadramaut (ToLCSDV-YE[YE:Had:89]). A distinct full-length betasatellite molecule (1352 bases) was cloned from the respective field-infected tomato and tobacco plants. Agro-inoculation of tomato and Nicotiana benthamiana plants with cloned partial tandem repeats of ToLCSDV-YE[YE:Tih11:05]) and the associated betasatellite, Tomato leaf curl Yemen betasatellite (ToLCYEB-[Tih:tom:137:05]), resulted in the reproduction of leaf curl disease symptoms in test plants like those observed in the field-infected plants. The betasatellite contributed to symptom severity in N. benthamiana test plants when it was co-inoculated with ToLCSDV-YE, compared to the milder symptoms that were observed in tobacco plants infected with the helper virus alone. © 2012 Elsevier B.V.

  10. Orbital forcing of glacial/interglacial variations in chemical weathering and silicon cycling within the upper White Nile basin, East Africa: Stable-isotope and biomarker evidence from Lakes Victoria and Edward

    Science.gov (United States)

    Cockerton, Helen E.; Street-Perrott, F. Alayne; Barker, Philip A.; Leng, Melanie J.; Sloane, Hilary J.; Ficken, Katherine J.

    2015-12-01

    On Quaternary time scales, the global biogeochemical cycle of silicon is interlocked with the carbon cycle through biotic enhancement of silicate weathering and uptake of dissolved silica by vascular plants and aquatic microalgae (notably diatoms, for which Si is an essential nutrient). Large tropical river systems dominate the export of Si from the continents to the oceans. Here, we investigate variations in Si cycling in the upper White Nile basin over the last 15 ka, using sediment cores from Lakes Victoria and Edward. Coupled measurements of stable O and Si isotopes on diatom separates were used to reconstruct past changes in lake hydrology and Si cycling, while the abundances of lipid biomarkers characteristic of terrestrial/emergent higher plants, submerged/floating aquatic macrophytes and freshwater algae document past ecosystem changes. During the late-glacial to mid-Holocene, 15-5.5 ka BP, orbital forcing greatly enhanced monsoon rainfall, forest cover and chemical weathering. Riverine inputs of dissolved silica from the lake catchments exceeded aquatic demand and may also have had lower Si-isotope values. Since 5.5 ka BP, increasingly dry climates and more open vegetation, reinforced by the spread of agricultural cropland over the last 3-4 ka, have reduced dissolved silica inputs into the lakes. Centennial-to millennial-scale dry episodes are also evident in the isotopic records and merit further investigation.

  11. West Nile electrification project

    OpenAIRE

    Prototype Carbon Fund of the World Bank

    2007-01-01

    Metadata only record In early 2004, the West Nile Rural Electrification Company Ltd. plans to start up their new efficient diesel generators in the West Nile towns of Arua and Nebbi, to provide reliable power to the population during the day and most of the night. This is the first carbon finance project that has been approved in Uganda, with an Emission Reductions Purchase Agreement signed in March 2003. The company must expand their customer base quickly, because not only their income fr...

  12. An Integrated Hydrological and Water Management Study of the Entire Nile River System - Lake Victoria to Nile Delta

    Science.gov (United States)

    Habib, Shahid; Zaitchik, Benjamin; Alo, Clement; Ozdogan, Mutlu; Anderson, Martha; Policelli, Fritz

    2011-01-01

    The Nile basin River system spans 3 million km(exp 2) distributed over ten nations. The eight upstream riparian nations, Ethiopia, Eretria, Uganda, Rwanda, Burundi, Congo, Tanzania and Kenya are the source of approximately 86% of the water inputs to the Nile, while the two downstream riparian countries Sudan and Egypt, presently rely on the river's flow for most of the their needs. Both climate and agriculture contribute to the complicated nature of Nile River management: precipitation in the headwaters regions of Ethiopia and Lake Victoria is variable on a seasonal and inter-annual basis, while demand for irrigation water in the arid downstream region is consistently high. The Nile is, perhaps, one of the most difficult trans-boundary water issue in the world, and this study would be the first initiative to combine NASA satellite observations with the hydrologic models study the overall water balance in a to comprehensive manner. The cornerstone application of NASA's Earth Science Research Results under this project are the NASA Land Data Assimilation System (LDAS) and the USDA Atmosphere-land Exchange Inverse (ALEXI) model. These two complementary research results are methodologically independent methods for using NASA observations to support water resource analysis in data poor regions. Where an LDAS uses multiple sources of satellite data to inform prognostic simulations of hydrological process, ALEXI diagnoses evapotranspiration and water stress on the basis of thermal infrared satellite imagery. Specifically, this work integrates NASA Land Data Assimilation systems into the water management decision support systems that member countries of the Nile Basin Initiative (NBI) and Regional Center for Mapping of Resources for Development (RCMRD, located in Nairobi, Kenya) use in water resource analysis, agricultural planning, and acute drought response to support sustainable development of Nile Basin water resources. The project is motivated by the recognition that

  13. Discover the Nile River

    Science.gov (United States)

    Project WET Foundation, 2009

    2009-01-01

    Bordering on the Fantastic. As the longest river on earth, the Nile passes through 10 countries. Presented through a wide range of activities and a winning array of games, it's also unsurpassed at taking young minds into exploring the world of water, as well as natural and man made wonders.

  14. Gravity Investigation in Area East of River Nile (Khartoum State)

    Institute of Scientific and Technical Information of China (English)

    Eldawi M G; Farwa A G

    2003-01-01

    The purpose of the study is to investigate the subsurface geology of the area. For quantitative interpretation of the resulting Bouguer anomalies, borehole data are explored. This is done along several profiles obtained from software program G. model C version 2. 2 No. 175. This program is based on two -dimensional mass distribution. The interpretation reveals two basinal features filling depressions in the basement complex named as Abu Harira basin and Kabbashi basin. They are structurally related to Khartoum basin. As a result, a geological/structural map of the area in east of the Nile is produced. The basinal features in the study area are considered as parts of the central Sudan (Khartoum basin) that had been subjected to several tectonic events that resulted in the formation of several fracture systems associated with block subsidence and formation of these basins.

  15. The Dusky Large Blue – Maculinea nausithous kijevensis (Sheljuzhko, 1928) in the Transylvanian basin: New data on taxonomy and ecology

    DEFF Research Database (Denmark)

    Rákosy, Laszló; Tartally, András; Goia, Marin;

    2010-01-01

    Maculinea nausithous (Bergsträsser, 1779) was recently discovered in two parts of the Transylvanian basin. External characters of these populations completely agree with the original description of Maculinea nausithous kijevensis (Sheljuzhko, 1928) and show some small but constant differences aga...... collected in northeastern Romania, in Kazakhstan and in the western part of the Altai Mts. Therefore we believe that this subspecies has a wider Euro-Siberian distribution....

  16. Impact of the Sudd wetland on the Nile hydroclimatology

    Science.gov (United States)

    Mohamed, Y. A.; van den Hurk, B. J. J. M.; Savenije, H. H. G.; Bastiaanssen, W. G. M.

    2005-08-01

    Large evaporation occurs over the Sudd wetland, a huge swamp located on the upper Nile. Historically, water resources planners have had the intention to reduce the Sudd evaporation by shortcut channels (e.g., Jonglei canal). The question is: What is the effect of draining the Sudd wetland on the regional water cycle and on the Nile water flow? A regional climate model has been applied to the Nile Basin, with a special modification to include routing of the Nile flood over the Sudd. The impact of the wetland on the Nile hydroclimatology has been studied by comparing two model scenarios: the present climatology and a drained Sudd scenario. The results indicate that draining the entire Sudd has negligible impact on the regional water cycle owing to the relatively small area covered by the wetland. The runoff gain would then be up to ~36 Gm3 yr-1. However, the impact on the microclimate is large. The relative humidity will drop by 30-40% during the dry season, and temperature will rise by 4°-6°C. The impact during the wet season is small.

  17. The Carbon Cycle at the Nile Headwaters

    Science.gov (United States)

    Jones, Michael; Saunders, Matthew

    2014-05-01

    The carbon cycle at the Nile headwaters M B Jones, School of Natural Sciences, Trinity College, University of Dublin, Dublin 2, Ireland M Saunders, Environmental and Biochemical Sciences Group, The James Hutton Institute, Aberdeen, Scotland River systems play an integral role in the global carbon cycle by connecting the terrestrial biosphere, the atmosphere and the oceans. Extensive wetland systems, such as those found in the Amazon region, have been shown to export significant amounts of carbon to river waters as dissolved carbon dioxide (CO2) that can be transported and emitted hundreds of km downstream. The assessment of both regional and global carbon budgets could therefore be improved by quantifying these lateral carbon fluxes, especially from highly productive temporarily or permanently flooded areas where substantial CO2 evasion from inland waters can occur. The Nile is the longest river in the world and the headwaters are located in the extensive Papyrus dominated wetlands in central Africa that are associated with Lake Victoria. From its source the White Nile flows northwards through wetlands in Uganda and Sudan before it joins the Blue Nile. Papyrus wetlands have been shown to be some of the most productive global ecosystems, with recorded rates of aerial net primary productivity of up to 3.09 kg C m-2 yr-1. In addition, where anaerobic conditions occur they also accumulate large amounts of carbon in the form of peat, and under these circumstances they represent a significant carbon sink. However, as water moves through these wetlands and is exchanged with surrounding rivers and lakes significant quantities of dissolved organic and inorganic carbon as well as suspended particulate organic matter are exported, which are either released further downstream by degassing, decomposition or deposition. Information on such losses from these wetland ecosystems is extremely sparse but in order to better constrain ecosystem scale carbon dynamics more accurate

  18. Nile behaviour and Late Palaeolithic humans in Upper Egypt during the Late Pleistocene

    Science.gov (United States)

    Vermeersch, Pierre M.; Van Neer, Wim

    2015-12-01

    The reconstruction of the environment and the human population history of the Nile Valley during the Late Pleistocene have received a lot of attention in the literature thus far. There seems to be a consensus that during MIS2 extreme dry conditions prevailed over north-eastern Africa, which was apparently not occupied by humans. The Nile Valley seems to be an exception; numerous field data have been collected suggesting an important population density in Upper Egypt during MIS2. The occupation remains are often stratified in, or at least related to, aeolian and Nile deposits at some elevation above the present-day floodplain. They are rich in lithics and animal bones, mainly fish, illustrating the exploitation of the Nile Valley by the Late Palaeolithic inhabitants. The fluvial processes active during that period have traditionally been interpreted as a continuously rising highly braided river. In this paper we summarize the evidence thus far available for the Late Pleistocene on the population densities in the Nile Valley, and on the models of Nilotic behaviour. In the discussion we include data on the environmental conditions in Eastern Africa, on the aeolian processes in the Western Desert of Egypt derived from satellite images, 14C and OSL dates, in order to formulate a new model that explains the observed high remnants of aeolian and Nilotic deposits and the related Late Palaeolithic sites. This model hypothesizes that, during the Late Pleistocene, and especially the LGM, dunes from the Western Desert invaded the Nile Valley at several places in Upper Egypt. The much reduced activity of the White Nile and the Blue Nile was unable to evacuate incoming aeolian sand and, as a consequence, several dams were created in the Upper Egyptian Nile Valley. Behind such dams the created lakes offered ideal conditions for human subsistence. This model explains the occurrence of Late Palaeolithic hunter-fisher-gatherers in a very arid environment with very low Nile flows

  19. Naturally occurring contaminants in the Piedmont and Blue Ridge crystalline-rock aquifers and Piedmont Early Mesozoic basin siliciclastic-rock aquifers, eastern United States, 1994–2008

    Science.gov (United States)

    Chapman, Melinda J.; Cravotta, Charles A.; Szabo, Zoltan; Lindsay, Bruce D.

    2013-01-01

    Groundwater quality and aquifer lithologies in the Piedmont and Blue Ridge Physiographic Provinces in the eastern United States vary widely as a result of complex geologic history. Bedrock composition (mineralogy) and geochemical conditions in the aquifer directly affect the occurrence (presence in rock and groundwater) and distribution (concentration and mobility) of potential naturally occurring contaminants, such as arsenic and radionuclides, in drinking water. To evaluate potential relations between aquifer lithology and the spatial distribution of naturally occurring contaminants, the crystalline-rock aquifers of the Piedmont and Blue Ridge Physiographic Provinces and the siliciclastic-rock aquifers of the Early Mesozoic basin of the Piedmont Physiographic Province were divided into 14 lithologic groups, each having from 1 to 16 lithochemical subgroups, based on primary rock type, mineralogy, and weathering potential. Groundwater-quality data collected by the U.S. Geological Survey (USGS) National Water-Quality Assessment (NAWQA) Program from 1994 through 2008 from 346 wells and springs in various hydrogeologic and land-use settings from Georgia through New Jersey were compiled and analyzed for this study. Analyses for most constituents were for filtered samples, and, thus, the compiled data consist largely of dissolved concentrations. Concentrations were compared to criteria for protection of human health, such as U.S. Environmental Protection Agency (USEPA) drinking water maximum contaminant levels and secondary maximum contaminant levels or health-based screening levels developed by the USGS NAWQA Program in cooperation with the USEPA, the New Jersey Department of Environmental Protection, and Oregon Health & Science University. Correlations among constituent concentrations, pH, and oxidation-reduction (redox) conditions were used to infer geochemical controls on constituent mobility within the aquifers. Of the 23 trace-element constituents evaluated

  20. Water balance modelling of the Nile River system to aid in understanding hydrologic interactions

    International Nuclear Information System (INIS)

    The importance of understanding the hydrology of the Nile Basin cannot be overstated. In this massive watershed, the interests of providing Nile countries with an adequate water supply competes with the need to protect unique and irreplaceable ecosystems like Lake Victoria and Lake Tana, the Equatorial lakes, and the Sudd swamp. Researchers worldwide have long studied various aspects of Nile Basin hydrology, from rainfall studies in the Ethiopian highlands to evaporation rates in Lake Nasser. An important aspect of the basin's hydrological cycle that has received less attention, however, has been the relative influence of groundwater in the basin. Groundwater plays an increasingly important role for Nile Basin countries. It is the source of water for irrigation and other uses in many parts of the basin; in some countries it provides large percentages of the urban water supply. Additionally, groundwater use is expected to increase significantly in the next decade, as is its vulnerability to pollution. However, limited information exists on the quantity and movement of groundwater in the Nile countries, particularly in relation to rivers, lakes, and wetlands - the surface waters - of the Nile system. A highly effective strategy for understanding interactions between surface water and groundwater is the use of water balance models. In their simplest form, water balances account for all the inputs and outputs of water in a given system, such as rainfall, evaporation, river flow, recharge to groundwater aquifers, and discharge of groundwater. Water balance models can be conducted on a variety of scales, from small headwater catchments to continental scale systems, such as the entire Nile Basin. The Isotope Hydrology Section is working with Nile countries on a project, funded by the Global Environment Facility (GEF) and implemented by the United Nations Development Programme (UNDP), entitled, 'Mainstreaming Groundwater Considerations into the Integrated Management of the

  1. Synthesis and optical properties of pyrrolidinyl peptide nucleic acid carrying a clicked Nile red label

    Directory of Open Access Journals (Sweden)

    Nattawut Yotapan

    2014-09-01

    Full Text Available DNA or its analogues with an environment-sensitive fluorescent label are potentially useful as a probe for studying the structure and dynamics of nucleic acids. In this work, pyrrolidinyl peptide nucleic acid (acpcPNA was labeled at its backbone with Nile red, a solvatochromic benzophenoxazine dye, by means of click chemistry. The optical properties of the Nile red-labeled acpcPNA were investigated by UV–vis and fluorescence spectroscopy in the absence and in the presence of DNA. In contrast to the usual quenching observed in Nile red-labeled DNA, the hybridization with DNA resulted in blue shifting and an enhanced fluorescence regardless of the neighboring bases. More pronounced blue shifts and fluorescence enhancements were observed when the DNA target carried a base insertion in close proximity to the Nile red label. The results indicate that the Nile red label is located in a more hydrophobic environment in acpcPNA–DNA duplexes than in the single-stranded acpcPNA. The different fluorescence properties of the acpcPNA hybrids of complementary DNA and DNA carrying a base insertion are suggestive of different interactions between the Nile red label and the duplexes.

  2. Environmental color affects Nile tilapia reproduction

    Directory of Open Access Journals (Sweden)

    Volpato G.L.

    2004-01-01

    Full Text Available We investigated the effects of environmental color on the reproductive behavior of Nile tilapia, Oreochromis niloticus. Two environmental colors were tested by covering the aquarium (60 x 60 x 40 cm with white (12 groups or blue (13 groups cellophane and observing reproductive behavior in groups of 2 males (10.27 ± 0.45 cm and 3 females (10.78 ± 0.45 cm each. After assignment to the respective environmental color (similar luminosity = 100 to 120 Lux, the animals were observed until reproduction (identified by eggs in the female's mouth or up to 10 days after the first nest building. Photoperiod was from 6:00 h to 18:00 h every day. Food was offered in excess once a day and water quality was similar among aquaria. Daily observations were made at 8:00, 11:00, 14:00 and 17:00 h regarding: a latency to the first nest, b number of nests, c gravel weight removed (the male excavates the nest in the bottom of the aquarium, d nest area, and e mouthbrooding incubation (indication of reproduction. The proportion of reproducing fish was significantly higher (6 of 13 in the group exposed to the blue color compared the group exposed to the white color (1 of 12; Goodman's test of proportions. Moreover, males under blue light removed significantly larger masses of gravel (blue = 310.70 ± 343.50 g > white = 130.38 ± 102.70 g; P = 0.01 and constructed wider nests (blue = 207.93 ± 207.80 cm² > white = 97.68 ± 70.64 cm²; P = 0.03 than the control (white. The other parameters did not differ significantly between light conditions. We concluded that reproduction in the presence of blue light was more frequent and intense than in the presence of white light.

  3. Mental Status after West Nile Virus Infection

    OpenAIRE

    Haaland, Kathleen Y.; Sadek, Joseph; Pergam, Steven; Echevarria, Leonor A.; Davis, Larry E.; Goade, Diane; Harnar, Joanne; Nofchissey, Robert A.; Sewel, C. Mack; Ettestad, Paul

    2006-01-01

    Mental status after acute West Nile virus infection has not been examined objectively. We compared Telephone Interview for Cognitive Status scores of 116 patients with West Nile fever or West Nile neuroinvasive disease. Mental status was poorer and cognitive complaints more frequent with West Nile neuroinvasive disease (p = 0.005).

  4. A review of seawater intrusion in the Nile Delta groundwater system – the basis for assessing impacts due to climate changes and water resources development

    NARCIS (Netherlands)

    Mabrouk, M.B.; Jonoski, A.; Solomatine, D.P.; Uhlenbrook, S.

    2013-01-01

    Serious environmental problems are emerging in the River Nile basin and its groundwater resources. Recent years have brought scientific evidence of climate change and development-induced environmental impacts globally as well as over Egypt. Some impacts are subtle, like decline of the Nile River wat

  5. Postpartum Blues

    Medline Plus

    Full Text Available ... blues The postpartum blues E-mail to a friend Please fill in all fields. Please enter a ... blues: Talk to your partner or a good friend about how you feel Get plenty of rest ...

  6. The Landscape and Archaeology of Jebel Sabaloka and the Sixth Nile Cataract, Sudan

    Directory of Open Access Journals (Sweden)

    Lenka Suková

    2012-12-01

    Full Text Available There are only six cataracts on the Main Nile of which the sixth Nile cataract located ca. 80 km downstream of the confluence of the Blue and White Niles represents the southernmost and smallest of theseries. Despite its close vicinity to Khartoum, this area was the least studied cataract zone along the Middle Nile until 2009 when it became the object of geoarchaeological research by the Czech Institute of Egyptology (Faculty of Arts, Charles University in Prague and the Institute of Geology (Academy of Sciences of the Czech Republic. Four field campaigns have been carried out in Jebel Sabaloka and the Sixth Nile Cataract up to now, of which the first two were focused on landscape archaeology of a “large scale”, i.e. on the recognition of all observable human influencesin the research area of approx. 15×20 km. The main result of the first landscape archaeological reconnaissance consistsin the localisation and first description of ca. 30 major sites spanning from the Middle Palaeolithic up to the recent past. A peculiar archaeological feature of this part of the nile Valley has turned out to be the existence of a dense network of terraced “villages” connected via old paths with the Nile and with the periphery of the mountains. Furthermore, two Christian and Islamic forts have been found at places guarding the crossing of the Nile above the sixth cataract. Last but not least, a large number of prehistoric sites, including an extraordinarily rich settlement dated to the Mesolithic and Neolithic periods, has been described as well. After the first two seasons, the findings of which are summarised in this paper, it can be argued that the last of the six Nile cataracts to be investigated has finally begun to reveal its rich and hitherto unknown archaeological past.

  7. Developing the greatest Blue Economy: Water productivity, fresh water depletion, and virtual water trade in the Great Lakes basin

    Science.gov (United States)

    Mayer, Alex; Mubako, Stanley; Ruddell, Benjamin L.

    2016-06-01

    The Great Lakes basin hosts the world's most abundant surface fresh water reserve. Historically an industrial and natural resource powerhouse, the region has suffered economic stagnation in recent decades. Meanwhile, growing water resource scarcity around the world is creating pressure on water-intensive human activities. This situation creates the potential for the Great Lakes region to sustainably utilize its relative water wealth for economic benefit. We combine economic production and trade datasets with water consumption data and models of surface water depletion in the region. We find that, on average, the current economy does not create significant impacts on surface waters, but there is some risk that unregulated large water uses can create environmental flow impacts if they are developed in the wrong locations. Water uses drawing on deep groundwater or the Great Lakes themselves are unlikely to create a significant depletion, and discharge of groundwater withdrawals to surface waters offsets most surface water depletion. This relative abundance of surface water means that science-based management of large water uses to avoid accidentally creating "hotspots" is likely to be successful in avoiding future impacts, even if water use is significantly increased. Commercial water uses are the most productive, with thermoelectric, mining, and agricultural water uses in the lowest tier of water productivity. Surprisingly for such a water-abundant economy, the region is a net importer of water-derived goods and services. This, combined with the abundance of surface water, suggests that the region's water-based economy has room to grow in the 21st century.

  8. Natural equilibria and anthropic effects on sediment transport in big river systems: The Nile case

    Science.gov (United States)

    Garzanti, Eduardo; Andò, Sergio; Padoan, Marta; Vezzoli, Giovanni; Villa, Igor

    2014-05-01

    The Nile River flows for ~ 6700 km, from Burundi and Rwanda highlands south of the Equator to the Mediterranean Sea at northern subtropical latitudes. It is thus the longest natural laboratory on Earth, a unique setting in which we are carrying out a continuing research project to investigate changes in sediment composition associated with a variety of chemical and physical processes, including weathering in equatorial climate and hydraulic sorting during transport and deposition. Petrographic, mineralogical, chemical, and isotopic fingerprints of sand and mud have been monitored along all Nile branches, from the Kagera and White Nile draining Archean, Paleoproterozoic and Mesoproterozoic basements uplifted along the western branch of the East African rift, to the Blue Nile and Atbara Rivers sourced in Ethiopian volcanic highlands made of Oligocene basalt. Downstream of the Atbara confluence, the Nile receives no significant tributary water and hardly any rainfall across the Sahara. After construction of the Aswan High Dam in 1964, the Nile ceased to be an active conveyor-belt in Egypt, where the mighty river has been tamed to a water canal; transported sediments are thus chiefly reworked from older bed and levee deposits, with minor contributions from widyan sourced in the Red Sea Hills and wind-blown desert sand and dust. Extensive dam construction has determined a dramatic sediment deficit at the mouth, where deltaic cusps are undergoing ravaging erosion. Nile delta sediments are thus recycled under the effect of dominant waves from the northwest, the longest Mediterranean fetch direction. Nile sands, progressively enriched in more stable minerals such as quartz and amphiboles relative to volcanic rock fragments and pyroxene, thus undergo multistep transport by E- and NE-directed longshore currents all along the coast of Egypt and Palestine, and are carried as far as Akko Bay in northern Israel. Nile mud reaches the Iskenderun Gulf in southern Turkey. A full

  9. West Nile Virus Cases, 2006-present

    Data.gov (United States)

    U.S. Department of Health & Human Services — This dataset contains positive cases of West Nile virus found in humans by county of residence, 2006-present. Humans usually become infected with West Nile virus by...

  10. A review of green- and blue-water resources and their trade-offs for future agricultural production in the Amazon Basin: what could irrigated agriculture mean for Amazonia?

    Science.gov (United States)

    Lathuillière, Michael J.; Coe, Michael T.; Johnson, Mark S.

    2016-06-01

    The Amazon Basin is a region of global importance for the carbon and hydrological cycles, a biodiversity hotspot, and a potential centre for future economic development. The region is also a major source of water vapour recycled into continental precipitation through evapotranspiration processes. This review applies an ecohydrological approach to Amazonia's water cycle by looking at contributions of water resources in the context of future agricultural production. At present, agriculture in the region is primarily rain-fed and relies almost exclusively on green-water resources (soil moisture regenerated by precipitation). Future agricultural development, however, will likely follow pathways that include irrigation from blue-water sources (surface water and groundwater) as insurance from variability in precipitation. In this review, we first provide an updated summary of the green-blue ecohydrological framework before describing past trends in Amazonia's water resources within the context of land use and land cover change. We then describe green- and blue-water trade-offs in light of future agricultural production and potential irrigation to assess costs and benefits to terrestrial ecosystems, particularly land and biodiversity protection, and regional precipitation recycling. Management of green water is needed, particularly at the agricultural frontier located in the headwaters of major tributaries to the Amazon River, and home to key downstream blue-water users and ecosystem services, including domestic and industrial users, as well as aquatic ecosystems.

  11. Postpartum Blues

    Medline Plus

    Full Text Available ... Quality Collaboratives Launch Prematurity research centers What is team science? More than 75 years of solving problems ... delivery cause the postpartum blues. How can you manage the baby blues? The American College of Obstetricians ...

  12. Postpartum Blues

    Medline Plus

    Full Text Available ... with this condition are happy most of the time. But compared to how she usually feels, the ... the "blues" usually lessens and goes away over time. What causes the baby blues? Medical experts believe ...

  13. Postpartum Blues

    Medline Plus

    Full Text Available ... Postpartum care > The postpartum blues The postpartum blues E-mail to a friend Please fill in all fields. Please enter a valid e-mail address. Your information: Your recipient's information: Your ...

  14. Postpartum Blues

    Medline Plus

    Full Text Available ... can you manage the baby blues? The American College of Obstetricians and Gynecologists recommends that women do ... can you manage the baby blues? The American College of Obstetricians and Gynecologists recommends that women do ...

  15. Postpartum Blues

    Medline Plus

    Full Text Available ... Feels sad Feels confused The postpartum blues peak three to five days after delivery. They usually end ... Feels sad Feels confused The postpartum blues peak three to five days after delivery. They usually end ...

  16. Postpartum Blues

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    Full Text Available ... postpartum blues The postpartum blues E-mail to a friend Please fill in all fields. Please enter ... hear about breakthroughs for babies and families. Ask a question Our health experts can answer questions about ...

  17. Postpartum Blues

    Medline Plus

    Full Text Available ... Medical experts believe that changes in the woman's hormones after delivery cause the postpartum blues. How can ... Medical experts believe that changes in the woman's hormones after delivery cause the postpartum blues. How can ...

  18. A new model of river dynamics, hydroclimatic change and human settlement in the Nile Valley derived from meta-analysis of the Holocene fluvial archive

    Science.gov (United States)

    Macklin, Mark G.; Toonen, Willem H. J.; Woodward, Jamie C.; Williams, Martin A. J.; Flaux, Clément; Marriner, Nick; Nicoll, Kathleen; Verstraeten, Gert; Spencer, Neal; Welsby, Derek

    2015-12-01

    In the Nile catchment, a growing number of site- and reach-based studies employ radiocarbon and, more recently, OSL dating to reconstruct Holocene river histories, but there has been no attempt to critically evaluate and synthesise these data at the catchment scale. We present the first meta-analysis of published and publically available radiocarbon and OSL dated Holocene fluvial units in the Nile catchment, including the delta region, and relate this to changing climate and river dynamics. Dated fluvial units are separated both geographically (into the Nile Delta and White, Blue, and Desert Nile sub-regions) and into depositional environment (floodplain and palaeochannel fills). Cumulative probability density frequency (CPDF) plots of floodplain and palaeochannel units show a striking inverse relationship during the Holocene, reflecting abrupt (civilizations in the Nile Valley.

  19. Inter- and intra-annual variation of water footprint of crops and blue water scarcity in the Yellow River basin (1961-2009)

    NARCIS (Netherlands)

    Zhuo, L.; Mekonnen, M.M.; Hoekstra, A.Y.; Wada, Y.

    2016-01-01

    The Yellow River Basin (YRB), the second largest river basin of China, has experienced a booming agriculture over the past decades. But data on variability of and trends in water consumption, pollution and scarcity in the YRB are lacking. We estimate, for the first time, the inter- and intra-annual

  20. Socioeconomic dynamics of water quality in the Egyptian Nile

    Science.gov (United States)

    Malik, Maheen; Nisar, Zainab; Karakatsanis, Georgios

    2016-04-01

    The Nile River remains the most important source of freshwater for Egypt as it accounts for nearly all of the country's drinking and irrigation water. About 95% of the total population is accounted to live along the Banks of the Nile(1). Therefore, water quality deterioration in addition to general natural scarcity of water in the region(2) is the main driver for carrying out this study. What further aggravates this issue is the water conflict in the Blue Nile region. The study evaluates different water quality parameters and their concentrations in the Egyptian Nile; further assessing the temporal dynamics of water quality in the area with (a) the Environmental Kuznets Curve (EKC)(3) and (b) the Jevons Paradox (JP)(4) in order to identify water quality improvements or degradations using selected socioeconomic variables(5). For this purpose various environmental indicators including BOD, COD, DO, Phosphorus and TDS were plotted against different economic variables including Population, Gross Domestic Product (GDP), Annual Fresh Water Withdrawal and Improved Water Source. Mathematically, this was expressed by 2nd and 3rd degree polynomial regressions generating the EKC and JP respectively. The basic goal of the regression analysis is to model and highlight the dynamic trend of water quality indicators in relation to their established permissible limits, which will allow the identification of optimal future water quality policies. The results clearly indicate that the dependency of water quality indicators on socioeconomic variables differs for every indicator; while COD was above the permissible limits in all the cases despite of its decreasing trend in each case, BOD and phosphate signified increasing concentrations for the future, if they continue to follow the present trend. This could be an indication of rebound effect explained by the Jevons Paradox i.e. water quality deterioration after its improvement, either due to increase of population or intensification

  1. Kind of Blue - Europa Blues

    DEFF Research Database (Denmark)

    Mortensen, Tore; Kirkegaard, Peter

    2009-01-01

    Bidraget reflekterer over sammenhænge mellem to værker fra det musikalske og litterære område. Det drejer sig om Miles Davis' Kind of Blue fra 1959 og Arne Dahls krimi, Europa Blues fra 2001. Den grundlæggende indfaldsvinkel er det performative, den frie, men samtidigt disciplinerede musikalske...

  2. Seasonal forecasts of drought indices in African basins

    Directory of Open Access Journals (Sweden)

    E. Dutra

    2012-09-01

    Full Text Available Vast parts of Africa rely on the rainy season for livestock and agriculture. Droughts can have a severe impact in these areas which often have a very low resilience and limited capabilities to mitigate their effects. This paper tries to assess the predictive capabilities of an integrated drought monitoring and forecasting system based on the Standard precipitation index (SPI. The system is firstly constructed by temporally extending near real-time precipitation fields (ECMWF ERA-Interim reanalysis and the Climate Anomaly Monitoring System-Outgoing Longwave Radiation Precipitation Index, CAMS-OPI with forecasted fields as provided by the ECMWF seasonal forecasting system and then is evaluated over four basins in Africa: the Blue Nile, Limpopo, Upper Niger, and Upper Zambezi. There are significant differences in the quality of the precipitation between the datasets depending on the catchments, and a general statement regarding the best product is difficult to make. All the datasets show similar patterns in the South and North West Africa, while there is a low correlation in the tropical region which makes it difficult to define ground truth and choose an adequate product for monitoring. The Seasonal forecasts have a higher reliability and skill in the Blue Nile, Limpopo and Upper Niger in comparison with the Zambezi. This skill and reliability depends strongly on the SPI time-scale, and more skill is observed at larger time-scales. The ECMWF seasonal forecasts have predictive skill which is higher than using climatology for most regions. In regions where no reliable near real-time data is available, the seasonal forecast can be used for monitoring (first month of forecast. Furthermore, poor quality precipitation monitoring products can reduce the potential skill of SPI seasonal forecasts in two to four months lead time.

  3. Postpartum Blues

    Medline Plus

    Full Text Available ... leader Partner Spotlight Become a partner World Prematurity Day Your support helps babies We are determined to ... confused The postpartum blues peak three to five days after delivery. They usually end by the tenth ...

  4. Postpartum Blues

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    Full Text Available ... Saving Just a moment, please. You've saved this page It's been added to your dashboard . After ... blues" is not really correct since women with this condition are happy most of the time. But ...

  5. Postpartum Blues

    Medline Plus

    Full Text Available ... dashboard . After the baby is born, many new mothers have the postpartum blues (also called the baby ... compared to how she usually feels, the new mother: Is more irritable Cries more easily Feels sad ...

  6. Postpartum Blues

    Medline Plus

    Full Text Available ... for your baby Feeding your baby Common illnesses New parents Family health & safety Complications & Loss Pregnancy complications ... your dashboard . After the baby is born, many new mothers have the postpartum blues (also called the ...

  7. A distal 140 kyr sediment record of Nile discharge and East African monsoon variability

    Science.gov (United States)

    Ehrmann, Werner; Schmiedl, Gerhard; Seidel, Martin; Krüger, Stefan; Schulz, Hartmut

    2016-03-01

    Clay mineral assemblages in a sediment core from the distal Nile discharge plume off Israel have been used to reconstruct the late Quaternary Nile sediment discharge into the eastern Mediterranean Sea (EMS). The record spans the last ca. 140 kyr. Smectite abundances indicate the influence of the Blue Nile and the Atbara River that have their headwaters in the volcanic rocks of the Ethiopian Highlands. Kaolinite abundances indicate the influence of wadis, which contribute periodically to the suspension load of the Nile. Due to the geographical position, the climate and the sedimentary framework of the EMS is controlled by two climate systems. The long-term climate regime was governed by the African monsoon that caused major African humid periods (AHPs) with enhanced sediment discharge at 132 to AHP 5), 116 to 99 (AHP4), and 89 to 77 ka (AHP3). They lasted much longer than the formation of the related sapropel layers S5 (> 2 kyr), S4 (3.5 kyr), and S3 (5 kyr). During the last glacial period (Marine Isotope Stages (MISs) 4-2), the long-term changes in the monsoonal system were superimposed by millennial-scale changes in an intensified midlatitude glacial system. This climate regime caused short but pronounced drought periods in the Nile catchment, which are linked to Heinrich events and alternate with more humid interstadials. The clay mineral record further implies that feedback mechanisms between vegetation cover and sediment discharge of the Nile are detectable but of minor importance for the sedimentary record in the southeastern Mediterranean Sea during the investigated African humid periods.

  8. West Nile virus: a growing concern?

    OpenAIRE

    Gould, L. Hannah; Fikrig, Erol

    2004-01-01

    West Nile virus was first detected in North America in 1999 and has subsequently spread throughout the United States and Canada and into Mexico and the Caribbean. This review describes the epidemiology and ecology of West Nile virus in North America and the prospects for effective treatments and vaccines.

  9. Blue gods, blue oil, and blue people.

    Science.gov (United States)

    Fairbanks, V F

    1994-09-01

    Studies of the composition of coal tar, which began in Prussia in 1834, profoundly affected the economies of Germany, Great Britain, India, and the rest of the world, as well as medicine and surgery. Such effects include the collapse of the profits of the British indigo monopoly, the growth in economic power of Germany based on coal tar chemistry, and an economic crisis in India that led to more humane tax laws and, ultimately, the independence of India and the end of the British Empire. Additional consequences were the development of antiseptic surgery and the synthesis of a wide variety of useful drugs that have eradicated infections and alleviated pain. Many of these drugs, particularly the commonly used analgesics, sulfonamides, sulfones, and local anesthetics, are derivatives of aniline, originally called "blue oil" or "kyanol." Some of these aniline derivatives, however, have also caused aplastic anemia, agranulocytosis, and methemoglobinemia (that is, "blue people"). Exposure to aniline drugs, particularly when two or three aniline drugs are taken concurrently, seems to be the commonest cause of methemoglobinemia today. PMID:8065194

  10. Quantifying Knick Point Migration Rates Related to the Messinian Crisis. The Case of the Nile River

    Science.gov (United States)

    Stüwe, Kurt; Pucher, Christoph; Robl, Jörg; Hergarten, Stefan

    2016-04-01

    The Messinian crisis is a temporally well-constrained period between 5.3 my and 5.9 my, when the strait of Gibraltar was tectonically closed and the Mediterranean Sea had consequently desiccated. This dramatic base level drop by about 1500 vertical meters had a profound influence on the geomorphic evolution of the major drainages surrounding the Mediterranean basin. In particular, it caused substantial knickpoints in the major rivers including the Rhone, the Ebro, the Po and the Nile. While the knickpoints of the Rhone and Ebro have been studied previously and the knickpoints created by the Po may lie today underneath the Po plains, the knickpoint and its migration along the Nile has not been studied and would have migrated along its current river channel. In this contribution we focus on numerical modelling of the knickpoint migration in the Nile and use our modelling results in comparison with the present day morphological analyses of the river to constrain absolute migration rates. We suspect that the first Nile cataract near Assuan, some 1000 km upstream of today's river mouth may be the relict of the Messinian salinity crisis making it to one of the fastest migrating knickpoints in the world.

  11. NNDSS - Table II. West Nile virus disease

    Data.gov (United States)

    U.S. Department of Health & Human Services — NNDSS - Table II. West Nile virus disease - 2015.In this Table, provisional cases of selected notifiable diseases (≥1,000 cases reported during the preceding...

  12. Influence of environmental color on zootechnical performance and feeding behavior during masculinization of Nile tilapia

    Directory of Open Access Journals (Sweden)

    Perila Maciel Rebouças

    2014-10-01

    Full Text Available The rise of tilapia in Brazil and the world increasingly needs the best growing conditions. Despite the Nile tilapia has diurnal, your vision is considered a strong sensory stimulus, and as the perception of the color contrast of medium, production losses may be evidence due to stress caused too. Thus, an experiment was conducted at Biotechnology Aquaculture Applied Center (CEBIAQUA, The Fishing Engineering Department, Federal University of Ceará, with the aim of evaluating the influence of the background color translucent on zootechnical performance and feeding behavior of Nile tilapia during masculinization. We used 200 post-larvae (average weight = 0:02 ± 0.01g; mean initial length = 1.10 ± 0.01 cm of Nile tilapia, packed in 40 L aquarium, covered with cellophane, for 28 days. Fish were distributed in a completely randomized in two treatments (blue and green and five replications. Environmental variables analyzed were dissolved oxygen, temperature, pH and photoperiod and productive performance was evaluated weight, total length, condition factor and lot uniformity. Behavioral observations occurred twice daily, immediately before the first feeding and 2 minutes after each feeding treatment. We found no significant difference in water parameters in two treatments. The weight, length and condition factor did not differ between treatments. There was a higher survival rate, more lot uniformity, and an obvious grouped behavior during feeding in aquaria translucent greens than blues. So for the masculinization of Nile tilapia, it is recommended to translucent green, because the results were most satisfactory.

  13. West Nile virus: North American experience

    Science.gov (United States)

    Hofmeister, Erik K.

    2011-01-01

    West Nile virus, a mosquito-vectored flavivirus of the Japanese encephalitis serogroup, was first detected in North America following an epizootic in the New York City area in 1999. In the intervening 11 years since the arrival of the virus in North America, it has crossed the contiguous USA, entered the Canadian provinces bordering the USA, and has been reported in the Caribbean islands, Mexico, Central America and, more recently, South America. West Nile virus has been reported in over 300 species of birds in the USA and has caused the deaths of thousands of birds, local population declines of some avian species, the clinical illness and deaths of thousands of domestic horses, and the clinical disease in over 30 000 Americans and the deaths of over 1000. Prior to the emergence of West Nile virus in North America, St. Louis encephalitis virus and Dengue virus were the only other known mosquito-transmitted flaviviruses in North America capable of causing human disease. This review will discuss the North American experience with mosquito-borne flavivirus prior to the arrival of West Nile virus, the entry and spread of West Nile virus in North America, effects on wild bird populations, genetic changes in the virus, and the current state of West Nile virus transmission.

  14. Review of Tour of the Nile [iPad App

    Directory of Open Access Journals (Sweden)

    Helen Strudwick

    2013-07-01

    Full Text Available A review of the iPad app, Tour of the Nile. The app promises 'a virtual journey along the Nile Valley' plus the chance to 'handle' objects through the technology of augmented reality.

  15. Posthuman blues

    CERN Document Server

    Tonnies, Mac

    2013-01-01

    Posthuman Blues, Vol. I is first volume of the edited version of the popular weblog maintained by author Mac Tonnies from 2003 until his tragic death in 2009. Tonnies' blog was a pastiche of his original fiction, reflections on his day-to-day life, trenchant observations of current events, and thoughts on an eclectic range of material he culled from the Internet. What resulted was a remarkably broad portrait of a thoughtful man and the complex times in which he lived, rendered with intellige...

  16. ITCZ and ENSO-like pacing of Nile delta hydro-geomorphology during the Holocene

    Science.gov (United States)

    Marriner, Nick; Flaux, Clément; Kaniewski, David; Morhange, Christophe; Leduc, Guillaume; Moron, Vincent; Chen, Zhongyuan; Gasse, Françoise; Empereur, Jean-Yves; Stanley, Jean-Daniel

    2012-06-01

    The Nile valley accommodates the world's longest river and shaped the development of numerous complex societies, providing a reliable source of water for farming and linking populations to sub-Saharan Africa and the Mediterranean Sea. Its fertile delta lay at the heart of ancient Egyptian civilization, however little is known of its morpho-sedimentary response to basin-wide changes in Holocene hydrology. Here, we present two well-resolved records from the Nile delta (based on ˜320 radiocarbon dates) to reconstruct the timing and rhythm of catchment-scale modifications during the past 8000 years. On the orbital timescale, we demonstrate that Nilotic hydrology and sedimentation have responded to low-latitude insolation forcing while, on sub-millennial timescales, many of the major phases of deltaic modification were mediated by climate events linked to El Niño Southern Oscillation-type (ENSO) variability.

  17. N Isotopes in Nile Sediments (ethiopia, Sudan)

    Science.gov (United States)

    Padoan, M.; Villa, I. M.; Garzanti, E.; Galbusera, M.; Quistini, S.; Peruta, L.; El Kammar, A.

    2009-04-01

    The Nile is the most important river of the Eastern Mediterranean. Its water and sediment fluxes have greatly influenced marine circulation throughout the Quaternary, and are widely considered as possible causes for stagnation and formation of sapropel (Krom et al., 1999a; 2002; Talbot et al., 2000; Freydier et al., 2001; Weldeab et al., 2002; Scrivner et al., 2004). Variations in annual flooding and baseflow of the river Nile, controlled by climate changes, had major impact on the rise and demise of Egyptian dynasties (Stanley et al., 2003). In order to better define sedimentary sources of the Nile system and to obtain more robust results, we have analyzed Nd isotopes in sediments of all its major Sudanese and Ethiopian tributaries (Atbara, Gash, Abay, Didesa, Dabus, White Nile, Bahr Ez Zeraf) in several replicate samples. Analyses were carried out on distinct mud and sand fractions (STANLEY, J.D., CLIFF, R.A., WOODWARD, J.C., 2002. Nile River sediment fluctuations over the past 7000 yr and their key role in sapropel development. Geol., 30, n. 1, 71-74. PADOAN M., GALBUSERA M., QUISTINI S., VILLA I.M., AND GARZANTI E., 2007 Isotopic tracers of Nile sediment sources. AGU Fall Meeting, San Francisco December 2007. PIK, R., DENIEL, C., COULON, C., YIRGU, G., MARTY, B., 1999, Isotopic and trace element signatures of Ethiopian flood basalts: Evidence for plume-lithosphere interactions. Geochim. Cosmochim. Acta, 63, 2263-2279. SCRIVNER, A., VANCE, D., ROHLING, E.J., 2004. New neodymium isotope data quantify Nile involvement in Mediterranean anoxic episodes. Geol., 32, n. 7, 565-568. STANLEY, J.D., KROM, M.D., CLIFF, R.A., WOODWARD, J.C., 2003. Short Contribution: Nile flow failure at the End of the Old Kingdom, Egypt: strontium isotopic and petrologic evidence. TALBOT, M.R., WILLIAMS, M.A.J., ADAMSON, D.A., 2000. Strontium isotope evidence for late Pleistocene reestablishment of an integrated Nile drainage network. Geol., 28, n. 4, 343-346. WELDEAB, S., EMEIS, K

  18. West Nile Virus Drug Discovery

    Directory of Open Access Journals (Sweden)

    Siew Pheng Lim

    2013-12-01

    Full Text Available The outbreak of West Nile virus (WNV in 1999 in the USA, and its continued spread throughout the Americas, parts of Europe, the Middle East and Africa, underscored the need for WNV antiviral development. Here, we review the current status of WNV drug discovery. A number of approaches have been used to search for inhibitors of WNV, including viral infection-based screening, enzyme-based screening, structure-based virtual screening, structure-based rationale design, and antibody-based therapy. These efforts have yielded inhibitors of viral or cellular factors that are critical for viral replication. For small molecule inhibitors, no promising preclinical candidate has been developed; most of the inhibitors could not even be advanced to the stage of hit-to-lead optimization due to their poor drug-like properties. However, several inhibitors developed for related members of the family Flaviviridae, such as dengue virus and hepatitis C virus, exhibited cross-inhibition of WNV, suggesting the possibility to re-purpose these antivirals for WNV treatment. Most promisingly, therapeutic antibodies have shown excellent efficacy in mouse model; one of such antibodies has been advanced into clinical trial. The knowledge accumulated during the past fifteen years has provided better rationale for the ongoing WNV and other flavivirus antiviral development.

  19. Color vision: retinal blues.

    Science.gov (United States)

    Johnston, Jamie; Esposti, Federico; Lagnado, Leon

    2012-08-21

    Two complementary studies have resolved the circuitry underlying green-blue color discrimination in the retina. A blue-sensitive interneuron provides the inhibitory signal required for computing green-blue color opponency.

  20. Evaluation of regional-scale hydrological models using multiple criteria for 12 large river basins on all continents

    Science.gov (United States)

    Huang, Shaochun; Krysanova, Valentina; Hattermann, Fred; Vetter, Tobias; Flörke, Martina; Samaniego, Luis; Arheimer, Berit; Yang, Tao; van Griensven, Ann; Su, Buda; Gelfan, Alexander; Breuer, Lutz; Haberlandt, Uwe

    2016-04-01

    A good performance of hydrological impact models under historical climate and land use conditions is a prerequisite for reliable projections under climate change. The evaluation of nine regional-scale hydrological models considering monthly river discharge, long-term average seasonal dynamics and extremes was performed in the framework of the ISI-MIP project for 12 large river basins on all continents. The modelling tools include: ECOMAG, HBV, HYMOD, HYPE, mHM, SWAT, SWIM, VIC and WaterGAP3. These models were evaluated for the following basins: the Rhine and Tagus in Europe, the Niger and Blue Nile in Africa, the Ganges, Lena, Upper Yellow and Upper Yangtze in Asia, the Upper Mississippi, MacKenzie and Upper Amazon in America, and Darling in Australia. The model calibration and validation was done using WATCH climate data for all cases. The model outputs were evaluated using twelve statistical criteria to assess the fidelity of model simulations for monthly discharge, seasonal dynamics, flow duration curves, extreme floods and low flow. The reproduction of monthly discharge and seasonal dynamics was successful in all basins except the Darling, and the high flows and flood characteristics were also captured satisfactory in most cases. However, the criteria for low flow were below the thresholds in many cases. An overview of this collaborative experiment and main results on model evaluation will be presented.

  1. Groundwater geochemistry of nile delta-desert interface 1.isotope hydrology

    International Nuclear Information System (INIS)

    Sustenance and environmental protection of groundwater supply is of major concern in the integral environmental development in the arid to sub-arid regions in the Nile basin. Isotope data (18O, 2H and 3H) of groundwater in the west of the Nile delta indicates the contribution of palaeo groundwater component (in the range 0.1 - 0.8 with means of 0.39 and 0.52 for tahrir and khatatbah, respectively) along with sub recent recharge from the delta aquifer and recent recharge from irrigation conveyance canals in desert. Isotope mixing model (developed as Two-input table using excelTM spreads heat on apple MacintoshTM) is proposed to explain the apparent discrepancies in groundwater isotopic composition of khatatbah and tahrir areas assuming the contribution of two isotopically different palaeo-oples with two isotopically similar maind delta groundwater poles. About 0.30% 18O depletion per 10 Km downstream is detected and low northward groundwater recharge is suggested along 75 Km of the western strip of rosetta Nile. Higher sub-recent recharge from the main delta aquifer is believed to take place in khatatbah than tahrir whereas the last is believed to be replenished at present from the irrigation/ drainage network and irrigated fields with higher pollution risk for groundwater system in tahrir aquifer is exposed to northern marine intrusion. Lowering of the piezo metric level is to be expected in the newly exploited desertic areas under over pumping. 9 figs

  2. Production of Genetically Improved Organic Nile Tilapia

    NARCIS (Netherlands)

    Charo, H.; Komen, J.; Bovenhuis, H.; Rezk, M.A.; Ponzoni, R.W.

    2008-01-01

    Demand for organic products for human consumption has been on the increase due to the belief that organic products are safer and healthier to the consumer and the environment. In developing countries, Nile tilapia (Oreochromis niloticus) is usually grown in low-input organically fed ponds with littl

  3. Why We Need West Nile Virus Testing

    Centers for Disease Control (CDC) Podcasts

    2016-09-27

    Dr. Rodrigo Hasbun, a professor of infectious diseases at McGovern Medical School at UT Health, discusses the need for West Nile virus testing in Texas.  Created: 9/27/2016 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 9/27/2016.

  4. NNDSS - Table II. West Nile virus disease

    Data.gov (United States)

    U.S. Department of Health & Human Services — NNDSS - Table II. West Nile virus disease - 2016. In this Table, provisional* cases of selected†notifiable diseases (≥1,000 cases reported during the preceding...

  5. Synthesis and application of an aqueous nile red microemulsion for the development of fingermarks on porous surfaces.

    Science.gov (United States)

    de la Hunty, Mackenzie; Spindler, Xanthe; Chadwick, Scott; Lennard, Chris; Roux, Claude

    2014-11-01

    An oil-in-water microemulsion containing a luminescent dye, nile red, has been synthesised using a solvent-diffusion method. This has been demonstrated to be effective in developing fresh latent fingermarks on porous surfaces. The working solution is made using a binary surfactant solution to create a lactescent dual organic-aqueous phase intermediate, which subsequently results in a transparent microemulsion after the organic solvent has evaporated. The solution is non-toxic and performs comparatively with a previously published methanolic formulation but at a much lower cost and with an extended shelf life. The microemulsion outperforms a previously reported aqueous nile blue formulation for the development of both charged and natural fresh fingermarks, and requires lower exposure times for image recording.

  6. Spatial variability of evaporation and moisture storage in the swamps of the upper Nile studied by remote sensing techniques

    Science.gov (United States)

    Mohamed, Y. A.; Bastiaanssen, W. G. M.; Savenije, H. H. G.

    2004-04-01

    The water balance of the upper Nile swamps, in particular, the Sudd, has been the topic of debate for many years. Surface Energy Balance Algorithm for Land (SEBAL) is a parameterization scheme of surface heat fluxes based on spectral satellite measurements. The SEBAL scheme has been applied to derive the energy balance components from National Oceanic Atmospheric Administration-Advanced Very High Resolution Radiometer (NOAA-AVHRR) images over the extensive swamps in the upper Nile. The study area covers the swamps of the Sudd, Bahr el Ghazal and the Sobat sub-basins. The actual evaporation and soil moisture for an area between 2-12°N and 26-36°E (approximately 1000 km×1000 km) have been investigated. Monthly (actual) evaporation and soil moisture maps for the year 2000 have been generated. The evaporation results were verified against longer-term averaged rainfall and flow data of the three sub-basins. A close resemblance was obtained for the Sudd (1.8% error) and the Sobat Basin (5.7% error), while the balance lacks closure for the Ghazal basin (27%) due to un-gauged or inadequately gauged inflow from the upper catchments. It is concluded that soil moisture availability controls the monthly evaporation rates for all areas that are not saturated with water, and that a significant dry-down in the winter period occurs. It is concluded that the evaporation for the Sudd wetlands is 20% less and the average area occupied by the wetlands is 74% larger than assumed in earlier hydrological studies (e.g. Jonglei canal studies). The derived results can serve as a sound basis to support the widely debated evaporation losses from the Sudd, as well as form an input to regional scale climate models for studying atmospheric circulation patterns over Africa and the Nile Basin.

  7. West Nile viral infection of equids

    OpenAIRE

    Angenvoort, J.; Brault, A.C.; Bowen, R A; Groschup, M.H

    2013-01-01

    West Nile virus (WNV) is a flavivirus transmitted between certain species of birds and mosquito vectors. Tangential infections of equids and subsequent equine epizootics have occurred historically. Although the attack rate has been estimated to be below 10%, mortality rates can approach 50% in horses that present clinical disease. Symptoms are most commonly presenting in the form of encephalitis with ataxia as well as limb weakness, recumbency and muscle fasciculation. The most effective stra...

  8. The Nile floodplain, hydroclimatic variability, and its relation with cultural dynamics in ancient Thebes (Luxor, Egypt)

    Science.gov (United States)

    Toonen, Willem H. J.; Graham, Angus; Pennington, Ben; Hunter, Morag; Strutt, Kris; Barker, Dominic; Masson, Aurelia; Emery, Virginia

    2016-04-01

    were contemporary. The abundance of ceramic material also allowed the reconstruction of sedimentation rates across the floodplain, which ranged between 0.8-2.2 mm/yr, largely in agreement with estimates from other studies. Importantly, there seems to have been a major decrease in sedimentation rates after the New Kingdom. Furthermore, the abandonment of the secondary channel of the Nile and the formation of a well-developed calcareous palaeosol (both of which could have been forced by drought and failing Nile floods) correlate with the demise of the New Kingdom. This suggests that regionally observed cultural and natural dynamics may have been driven by hydroclimatic variability in the larger Nile basin. A lower calcareous palaeosol, located at least 1m below the New Kingdom horizon, hints at a previous period of severe drought and its age is tentatively inferred as Old Kingdom. The age of this lower palaeosol needs to be confirmed by more precise dating, but could support the idea that cultural dynamics in ancient floodwater farming cultures are strongly linked to hydroclimatic change.

  9. Blue cures blue but be cautious

    Directory of Open Access Journals (Sweden)

    Pranav Sikka

    2011-01-01

    Full Text Available Methemoglobinemia is a disorder characterized by the presence of >1% methemoglobin (metHb in the blood. Spontaneous formation of methemoglobin is normally counteracted by protective enzyme systems, for example, nicotinamide adenine dinucleotide phosphate (NADPH methemoglobin reductase. Methemoglobinemia is treated with supplemental oxygen and methylene blue (1-2 mg/kg administered slow intravenously, which acts by providing an artificial electron acceptor for NADPH methemoglobin reductase. But known or suspected glucose-6-phosphate dehydrogenase (G6PD deficiency is a relative contraindication to the use of methylene blue because G6PD is the key enzyme in the formation of NADPH through pentose phosphate pathway and G6PD-deficient individuals generate insufficient NADPH to efficiently reduce methylene blue to leukomethylene blue, which is necessary for the activation of the NADPH-dependent methemoglobin reductase system. So, we should be careful using methylene blue in methemoglobinemia patient before G6PD levels.

  10. Water quality and potamoplankton evaluation of the Nile River in Upper Egypt

    Directory of Open Access Journals (Sweden)

    Ahmed Mohamed El-Otify

    2015-06-01

    by the alternate dominance between diatoms and cyanobacteria, while zooplankton community was always dominated by rotifers. Phytoplankton populations were numerically more abundant in autumn and zooplankton peaked in spring.ConclusionsWastewater disposal restricted the abundance of the Nile zooplankton assemblages mainly due to the numerical decline of Rotifera and Cladocera. Otherwise, wastewater did not exert major limits for phytoplankton. The data obtained in this investigation will be crucial to understand potamoplankton regulation and contribute to the knowledge regarding the Limnology of the Nile basin.

  11. Nile behaviour and Upper Palaeolithic humans in Upper Egypt

    Science.gov (United States)

    Vermeersch, Pierre M.

    2014-05-01

    There is evidence of a decreasing human occupation of the Upper Egyptian Nile valley during the MIS 5 to MIS 3 period. Whereas very large extraction sites of the Middle Stone Age have been recorded, only very few sites of the Upper Palaeolithic have been found. The best explanation of this fact is that during the Late Middle Stone Age and the Upper Palaeolithc there was nearly no need for raw materials because there was only a very restricted population present in Upper Egypt. From about 22 ka BP an important population increase is registered by the presence of numerous Late Palaeolithic sites. During the whole LGM there is abundant presence of humans along the Nile Valley in Upper Egypt. This population was mainly living from fishing. There seems to be an abrupt end of the Palaeolithic occupation after 12.8 ka BP. Until now, no sites were found in the Valley until some rare Epipaleolithic sites occur about 8.0 ka BP. It will be suggested that these population changes are influenced by the river Nile behaviour. The best interpretation of the observations in the Upper Egyptian Nile Valley is the hypothesis that at the same time that Nile flow was reduced because of the dryness in its source area, the impact of aeolian activity was increased over Northeast Africa. The increased aeolian activity by northern winds in the Fayum and Wadi Ryan during the LGM resulted in the accumulation of aeolian sand in the valley. That aeolian sand was transported along the western Nile valley cliffs until it was accumulated when the Nile Valley change it S-N direction, such as at Nag'Hammadi. At other places sand was invading the Nile valley, directly from the Western Desert, creating a damming of the Nile at several places such as Armant and Aswan. As Nile flow was quite reduced, the Nile was unable to erode all the incoming sand and the Nile water with its important clay content was dammed. At several places large lakes were created in the Nile Valley. Those lakes were an ideal

  12. The evolution of the River Nile. The buried saline rift lakes in Sudan—I. Bahr El Arab Rift, the Sudd buried saline lake

    Science.gov (United States)

    Salama, Ramsis B.

    The River Nile in Sudan, was during the Tertiary, a series of closed lake basins. Each basin occupying one of the major Sudanese rift systems (Salama, 1985a). In this paper evidence is presented for the presence of the buried saline Sudd Lake in Bahr El Arab rift. The thick Tertiary sediments filling the deep grabens were eroded from the elevated blocks; Jebel Marra, Darfur Dome, Nuba Mountains and the Nile-Congo Divide. The thick carbonate deposits existing at the faulted boundaries of Bahr El Arab defines the possible boundaries between the fresh and saline water bodies. The widespread presence of kanker nodules in the sediments was a result of continuous efflorescence, leaching and evaporative processes. The highly saline zone in the central part of the Sudd was formed through the same processes with additional sulphate being added by the oxidation of the hydrogen sulphide gases emanating from the oil fields.

  13. Taxonomy Icon Data: Nile crocodile [Taxonomy Icon

    Lifescience Database Archive (English)

    Full Text Available Nile crocodile Crocodylus niloticus Chordata/Vertebrata/Reptilia/etc Crocodylus_nil...oticus_L.png Crocodylus_niloticus_NL.png Crocodylus_niloticus_S.png Crocodylus_niloticus_NS.png http://biosc...iencedbc.jp/taxonomy_icon/icon.cgi?i=Crocodylus+niloticus&t=L http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Crocodylus+ni...loticus&t=NL http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Crocodylus+ni...loticus&t=S http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Crocodylus+niloticus&t=NS ...

  14. Skin manifestations of West Nile virus infection.

    Science.gov (United States)

    Del Giudice, P; Schuffenecker, I; Zeller, H; Grelier, M; Vandenbos, F; Dellamonica, P; Counillon, E

    2005-01-01

    West Nile virus (WNV) infection is a potentially lethal arbovirus infection. Many notable outbreaks have occurred during the last few years throughout the world, including Europe and the USA. The severity of the disease is mainly related to the neurological complications. A maculopapular exanthema is reported as a clinical sign of the disease. Recently an outbreak of WNV infection occurred in southern France. Three patients out of 6 had a similar skin roseola-like eruption. The cluster of 3 cases of similar febrile roseola of unexplained cause during the same week led to the diagnosis of the first WNV human outbreak in France for 40 years. PMID:16286745

  15. Rising Sea Levels threatens the Nile Delta

    OpenAIRE

    Attia, Shady

    2007-01-01

    Like many other deltas, Egypt is particularly vulnerable to the effects of global warming. A relative rise in sea-level of 1 m would submerge much of the delta region within 30 km of the coast during the next 100 years. Rising sea levels would have significant long-term impacts on physical, biological and socio-economic conditions of the Nile Delta. These include the damage and destruction of buildings near beaches, erosion of beaches, salt-water intrusion, and flooding more than 1,200 km2 o...

  16. Assessment of future Nile flow through an ensemble of RCM simulations

    Science.gov (United States)

    Buontempo, Carlo; Ezzat Elshamy, Mohamed; Lørup, Jens Kristian; Jones, Richard; Butts, Mike; Betts, Richard; Hassan, Mohamed; Amin, Doaa M.; Kotb, Alaa-Eldin M.; Palin, Erika; Sanderson, Michael; McCarthy, Rachel

    2010-05-01

    The Nile represents a crucial resource for the economy of eastern and north-eastern Africa. Agriculture, energy production and livelihood in general depend strongly on the river. Assessing the impact that climate change may have on water resources is thus of critical importance for the people living in the Nile Basin. The objective of this study, carried out in close collaboration between the Ministry of Water Resources and Irrigation in Egypt, UK Met Office Hadley Centre and DHI, is to assess the possible impacts of climate change on the Nile river flow and in particular the inflow to the High Aswan Dam. Using climate models to inform water-related policies in the Nile Basin is a complex matter: the range of projections of change in both precipitation and river runoff tends to be wide with no consensus even on the sign of change. Previous studies (e.g. Conway & Hulme 1996; Strzepek & Yates 1996; Strzepek et al. 1996; Yates & Strzepek 1998) have shown the difficulty in assessing the impacts of climate change on Egyptian water resources. It is important to consider uncertainties in climate projections, since precise forecasts are not possible. Probabilistic projections have previously been generated by the Met Office Hadley Centre for the UK (the UK Climate Projections 2009, or UKCP09), involving a complex hierarchy of global and regional climate models, simple climate models and statistical techniques. Here we use an approach aligned to part of the full UKCP09 methodology, in which we perform a number of simulations with the PRECIS regional climate model driven by boundary conditions from several different variants of the HadCM3 GCM. Each of these versions was characterised by different values for a set of parameters that describe the basic unresolved physical processes (e.g. Palmer and Williams 2008) and simulate a range of plausible climate changes over the region. For this project a set of 5 GCM ensemble members was initially selected from the 17 transient runs

  17. Polychlorinated Biphenyls Water Pollution along the River Nile, Egypt

    Directory of Open Access Journals (Sweden)

    Ayman Mohamed Megahed

    2015-01-01

    Full Text Available Ten polychlorinated biphenyl (PCB congeners were determined in water samples collected along the River Nile using gas chromatography-electron capture detector (GC-ECD. PCB concentrations ranged from 14 to 20 μg/L, which were higher than those reported in previous studies, indicating serious PCB pollution in the River Nile. PCB congener profiles varied depending on the sampling sties. PCB-138 was the predominant congener accounting for more than 18% of total PCBs. The composition of PCB congeners in the water revealed that highly chlorinated PCB technical mixtures such as Aroclor 1254 was the main PCB production historically used in Egypt. An increasing trend in PCB levels from the upper stream to the Nile estuaries was observed. The calculated flux of PCBs indicated that 6.8 tons of PCBs is dumped into the Mediterranean Sea each year from the River Nile. The hazard quotients and carcinogenic risk caused by PCB pollution in the River Nile were above the acceptable level indicating that PCBs in the River Nile water pose adverse health effects for all age groups. Our findings revealed that PCBs possess a serious risk to the Egyptian population that depends mainly on the River Nile as a source of water. Thus, stricter legislation and regulatory controls should be applied to reduce the risk of PCBs in Egypt.

  18. Nile Delta vegetation response to Holocene climate variability

    Science.gov (United States)

    Bernhardt, Christopher E.; Horton, Benjamin P.; Stanley, Jean-Daniel

    2012-01-01

    A 7000 yr palynologic record from Burullus Lagoon, Nile Delta, Egypt, is assessed to investigate changes in terrestrial vegetation in response to Nile flow. Previous studies in this region have shown that sea-level rise in the early to mid-Holocene, and markedly increased human land use during the past several centuries, altered vegetation in and around the lagoon. The pollen record from this study documents changes in delta vegetation that likely reflect variations in Nile flow. We suggest that Cyperaceae pollen is a sensitive marker of precipitation over the Nile headwaters and the resultant Nile flow. Decreases in Cyperaceae pollen, interpreted as a marker for diminished Nile flow, as well as the increase in relative abundance of microscopic charcoal, occurred at ca. 6000–5500, ca. 5000, ca. 4200, and ca. 3000 cal. yr B.P. (calibrated years before present). These correspond to extreme regional and global aridity events associated with a more southerly mean position of the Intertropical Convergence Zone. These changes, also recorded by other proxy studies, indicate that several marked regional drought events affected the Nile Delta region and impacted ancient Egyptian and Middle Eastern civilizations.

  19. Blue and White Pot

    Institute of Scientific and Technical Information of China (English)

    1996-01-01

    Many recent archaeological studies have proven that the earliest blue and white porcelain was produced from the kiln in Gongxian County, Henan Province in the Tang Dynasty (618-907). It was an important variety of porcelain available for export then. The early blue and white porcelain in the Yuan Dynasty appeared dark and gray. During the reign of Zhizheng, clear blue and white porcelain was produced, indicating

  20. A Framework for Integrated Management of Transboundary Basins: the case of Sio sub-catchment in East Africa.

    OpenAIRE

    Obando, Joy A.; Makalle, Albinus; Bamutaze, Bamutaze

    2007-01-01

    The Sio sub-catchment is transboundary, originating in Kenya and flowing into Berkeley Bay of the Lake Victoria basin. It forms an important sub-catchment of the Nile basin and a significant base for the livelihood of small scale farmers engaged in mixed farming, depending on agriculture and livestock keeping as well as a large population depending on fishing. Indeed, high population densities exceeding 300 persons per square kilometre and cattle densities of 38 have been noted within basin, ...

  1. Feeling blue? Blue phosphors for OLEDs

    Directory of Open Access Journals (Sweden)

    Hungshin Fu

    2011-10-01

    Full Text Available Research on organic light emitting diodes (OLEDs has been revitalized, partly due to the debut of the OLED TV by SONY in 2008. While there is still plenty of room for improvement in efficiency, cost-effectiveness and longevity, it is timely to report on the advances of light emitting materials, the core of OLEDs, and their future perspectives. The focus of this account is primarily to chronicle the blue phosphors developed in our laboratory. Special attention is paid to the design strategy, synthetic novelty, and their OLED performance. The report also underscores the importance of the interplay between chemistry and photophysics en route to true-blue phosphors.

  2. Blue Willow Story Plates

    Science.gov (United States)

    Fontes, Kris

    2009-01-01

    In the December 1997 issue of "SchoolArts" is a lesson titled "Blue Willow Story Plates" by Susan Striker. In this article, the author shares how she used this lesson with her middle-school students many times over the years. Here, she describes a Blue Willow plate painting project that her students made.

  3. NNDSS - Table II. Varicella to West Nile virus disease

    Data.gov (United States)

    U.S. Department of Health & Human Services — NNDSS - Table II. Varicella to West Nile virus disease - 2014. In this Table, all conditions with a 5-year average annual national total of more than or equals...

  4. From blue jeans to blue genes.

    Science.gov (United States)

    Boon, Laurence M; Vikkula, Miikka

    2009-03-01

    Cutaneous venous anomalies are common. They are blue and vary in size, number, and location and account for most consultations at specialized interdisciplinary clinics for vascular anomalies. Venous lesions are clinically important because they cause pain, dysfunction, destruction of adjacent tissues, and esthetic concern. Only resection and sclerotherapy are helpful, although not always curative. Understanding etiopathogenesis could help design animal models and develop novel therapeutic approaches. John B. Mulliken, MD, envisioned a project to uncover the genetic basis of an inherited form of venous malformation in a large New England family. Recruitment of 2 young fellows resulted in a collaborative project that unraveled the searched-for gene and its mutation. This was an opening for a new era in vascular anomalies. Two blue genes' mutations were discovered, which account for most, if not all, of the inherited forms of venous anomalies, but other genes as well, for rheologically diverse lesions. Differential diagnosis and management has improved, and animal models are being made. This was achieved through the help of Dr Mulliken, who inspired 2 young investigators in blue jeans to find 2 blue genes.

  5. Niles Named To Head Virginia Tech's Newest College

    OpenAIRE

    Hincker, Lawrence

    2003-01-01

    Jerry Niles, interim dean of Virginia Tech's College of Human Sciences and Education and the college's former associate dean for innovation, graduate studies, and research, has been named dean of the university's newest college following an in-house search that began in January. Niles will assume the helm of the college, which will merge the College of Human Sciences and Education with the liberal arts departments in the current College of Arts and Sciences. His appointment is effective March...

  6. Polychlorinated Biphenyls Water Pollution along the River Nile, Egypt

    OpenAIRE

    Ayman Mohamed Megahed; Hesham Dahshan; Abd-El-Kader, Mahdy A.; Amr Mohamed Mohamed Abd-Elall; Mariam Hassan Elbana; Ehab Nabawy; Mahmoud, Hend A.

    2015-01-01

    Ten polychlorinated biphenyl (PCB) congeners were determined in water samples collected along the River Nile using gas chromatography-electron capture detector (GC-ECD). PCB concentrations ranged from 14 to 20 μg/L, which were higher than those reported in previous studies, indicating serious PCB pollution in the River Nile. PCB congener profiles varied depending on the sampling sties. PCB-138 was the predominant congener accounting for more than 18% of total PCBs. The composition of PCB cong...

  7. OPTIMUM WATER RESOURCES MANAGEMENT (OWRMIN THE MIDDLE-EAST&AL NILE VALLEY

    Directory of Open Access Journals (Sweden)

    NAJAH M. L. AL-MAIMURI

    2012-12-01

    Full Text Available An optimization water resources management study is developed in the Middle-East region and Al Nile Valley. It is based on assessment of hydrologic element of a specified area within the region, development of groundwater model, conjunctive use study, and rebalancing of the resulting water resources. Al Adhaim basin of 4110.28 km2which is located in northern-south of Iraq is chosen as sample of study for the availability of data. It is found that the optimization technique and rebalancing of the hydrologic elements in the considered area saves 282.8 million m3 per year of surface releases, reduces operation time of Kirkuk Irrigation Canal (KIC to 6 months per year, and treats the problems of water table rise due to the excessive surface water releases.

  8. Blue ocean strategy.

    Science.gov (United States)

    Kim, W Chan; Mauborgne, Renée

    2004-10-01

    Despite a long-term decline in the circus industry, Cirque du Soleil profitably increased revenue 22-fold over the last ten years by reinventing the circus. Rather than competing within the confines of the existing industry or trying to steal customers from rivals, Cirque developed uncontested market space that made the competition irrelevant. Cirque created what the authors call a blue ocean, a previously unknown market space. In blue oceans, demand is created rather than fought over. There is ample opportunity for growth that is both profitable and rapid. In red oceans--that is, in all the industries already existing--companies compete by grabbing for a greater share of limited demand. As the market space gets more crowded, prospects for profits and growth decline. Products turn into commodities, and increasing competition turns the water bloody. There are two ways to create blue oceans. One is to launch completely new industries, as eBay did with online auctions. But it's much more common for a blue ocean to be created from within a red ocean when a company expands the boundaries of an existing industry. In studying more than 150 blue ocean creations in over 30 industries, the authors observed that the traditional units of strategic analysis--company and industry--are of limited use in explaining how and why blue oceans are created. The most appropriate unit of analysis is the strategic move, the set of managerial actions and decisions involved in making a major market-creating business offering. Creating blue oceans builds brands. So powerful is blue ocean strategy, in fact, that a blue ocean strategic move can create brand equity that lasts for decades. PMID:15559577

  9. Blue ocean strategy.

    Science.gov (United States)

    Kim, W Chan; Mauborgne, Renée

    2004-10-01

    Despite a long-term decline in the circus industry, Cirque du Soleil profitably increased revenue 22-fold over the last ten years by reinventing the circus. Rather than competing within the confines of the existing industry or trying to steal customers from rivals, Cirque developed uncontested market space that made the competition irrelevant. Cirque created what the authors call a blue ocean, a previously unknown market space. In blue oceans, demand is created rather than fought over. There is ample opportunity for growth that is both profitable and rapid. In red oceans--that is, in all the industries already existing--companies compete by grabbing for a greater share of limited demand. As the market space gets more crowded, prospects for profits and growth decline. Products turn into commodities, and increasing competition turns the water bloody. There are two ways to create blue oceans. One is to launch completely new industries, as eBay did with online auctions. But it's much more common for a blue ocean to be created from within a red ocean when a company expands the boundaries of an existing industry. In studying more than 150 blue ocean creations in over 30 industries, the authors observed that the traditional units of strategic analysis--company and industry--are of limited use in explaining how and why blue oceans are created. The most appropriate unit of analysis is the strategic move, the set of managerial actions and decisions involved in making a major market-creating business offering. Creating blue oceans builds brands. So powerful is blue ocean strategy, in fact, that a blue ocean strategic move can create brand equity that lasts for decades.

  10. Assessment of macroinvertebrate communities in adjacent urban stream basins, Kansas City, Missouri, metropolitan area, 2007 through 2011

    Science.gov (United States)

    Christensen, Eric D.; Krempa, Heather M.

    2013-01-01

    Macroinvertebrates were collected as part of two separate urban water-quality studies from adjacent basins, the Blue River Basin (Kansas City, Missouri), the Little Blue River and Rock Creek Basins (Independence, Missouri), and their tributaries. Consistent collection and processing procedures between the studies allowed for statistical comparisons. Seven Blue River Basin sites, nine Little Blue River Basin sites, including Rock Creek, and two rural sites representative of Missouri ecological drainage units and the area’s ecoregions were used in the analysis. Different factors or levels of urban intensity may affect the basins and macroinvertebrate community metrics differently, even though both basins are substantially developed above their downstream streamgages (Blue River, 65 percent; Little Blue River, 52 percent). The Blue River has no flood control reservoirs and receives wastewater effluent and stormflow from a combined sewer system. The Little Blue River has flood control reservoirs, receives no wastewater effluent, and has a separate stormwater sewer system. Analysis of macroinvertebrate community structure with pollution-tolerance metrics and water-quality parameters indicated differences between the Blue River Basin and the Little Blue River Basin.

  11. Blue Ribbon Panel Report

    Science.gov (United States)

    An NCI Cancer Currents blog by the NCI acting director thanking the cancer community for contributing to the Cancer Moonshot Blue Ribbon Panel report, which was presented to the National Cancer Advisory Board on September 7.

  12. New York Blue

    Data.gov (United States)

    Federal Laboratory Consortium — New York Blue is used cooperatively by the Laboratory and Stony Brook University as part of the New York Center for Computation Sciences. Ranked as the 28th fastest...

  13. Up-to-date knowledge of West Nile virus infection

    Directory of Open Access Journals (Sweden)

    Hrnjaković-Cvjetković Ivana

    2009-01-01

    Full Text Available Virus West Nile virus is a single-stranded RNA virus of the family Flaviviridae, genus Flavivirus. Epidemiology West Nile virus is maintained in the cycle involving culicine mosquitoes and birds .Humans typically acquire West Nile infection through a bite from infected adult mosquito. Person to person transmission can occur through organ transplantation, blood and blood product transfusions, transplacentally and via brest milk. Human cases of West Nile infections were recorded in Africa, Israel, Russia, India, Pakistan. In Romania in 1996 West Nile fever occurred with hundreds of neurologic cases and 17 fatalities. First human cases in the United States were in New York City where 59 persons were infected and had fever, meningitis, encephalitis and flaccid paralysis. Clinical manifestation Most human cases are asymptomatic. The majority of symptomatic patients have a self limited febrile illness. Fatigue, nausea, vomiting, eye pain, headache, myalgias, artralgias, lymphadenopathy and rash are common complaints. Less than 1% of all infected persons develop more severe neurologic illness including meningitis, encefalitis and flaccid paralysis. Laboratory diagnosis Diagnosis of West Nile virus infection is based on serologic testing, isolation of virus from patient samples and detection of viral antigen or viral genom. ELISA test and indirect immunofluorescenceassay are used for detecting IgM and IgG antibodies in serum and cerebrospinal fluid. Treatment In vitro studies have suggested that ribavirin and interferon alfa -2b may be useful in the treatment of West Nile virus disease. Prevention The most important measures are mosquito control program and personal protective measures. .

  14. Issues and challenges in spatial and temporal water allocation in the Nile Delta

    NARCIS (Netherlands)

    Wolters, Wouter; Smit, Robert; El-Din, Mohamed Nour; Ahmed, Eman Sayed; Froebrich, Jochen; Ritzema, Henk

    2016-01-01

    "Egypt is a gift of the Nile," wrote Herodotus, and indeed, without the Nile there would be no Egypt as the world knows it. Egypt is mainly dependent on the flow in the Nile River (with an agreed share of 55.5 BCM) and it receives about 1.3 BCM rainfall annually (mainly along the north coast). Th

  15. Use of Generalised Linear Models to quantify rainfall input uncertainty to hydrological modelling in the Upper Nile

    Science.gov (United States)

    Kigobe, M.; McIntyre, N.; Wheater, H. S.

    2009-04-01

    Interest in the application of climate and hydrological models in the Nile basin has risen in the recent past; however, the first drawback for most efforts has been the estimation of historic precipitation patterns. In this study we have applied stochastic models to infill and extend observed data sets to generate inputs for hydrological modelling. Several stochastic climate models within the Generalised Linear Modelling (GLM) framework have been applied to reproduce spatial and temporal patterns of precipitation in the Kyoga basin. A logistic regression model (describing rainfall occurrence) and a gamma distribution (describing rainfall amounts) are used to model rainfall patterns. The parameters of the models are functions of spatial and temporal covariates, and are fitted to the observed rainfall data using log-likelihood methods. Using the fitted model, multi-site rainfall sequences over the Kyoga basin are generated stochastically as a function of the dominant seasonal, climatic and geographic controls. The rainfall sequences generated are then used to drive a semi distributed hydrological model using the Soil Water and Assessment Tool (SWAT). The sensitivity of runoff to uncertainty associated with missing precipitation records is thus tested. In an application to the Lake Kyoga catchment, the performance of the hydrological model highly depends on the spatial representation of the input precipitation patterns, model parameterisation and the performance of the GLM stochastic models used to generate the input rainfall. The results obtained so far disclose that stochastic models can be developed for several climatic regions within the Kyoga basin; and, given identification of a stochastic rainfall model; input uncertainty due to precipitation can be usefully quantified. The ways forward for rainfall modelling and hydrological simulation in Uganda and the Upper Nile are discussed. Key Words: Precipitation, Generalised Linear Models, Input Uncertainty, Soil Water

  16. Global monthly water scarcity: blue water footprints versus blue water availability.

    Directory of Open Access Journals (Sweden)

    Arjen Y Hoekstra

    Full Text Available Freshwater scarcity is a growing concern, placing considerable importance on the accuracy of indicators used to characterize and map water scarcity worldwide. We improve upon past efforts by using estimates of blue water footprints (consumptive use of ground- and surface water flows rather than water withdrawals, accounting for the flows needed to sustain critical ecological functions and by considering monthly rather than annual values. We analyzed 405 river basins for the period 1996-2005. In 201 basins with 2.67 billion inhabitants there was severe water scarcity during at least one month of the year. The ecological and economic consequences of increasing degrees of water scarcity--as evidenced by the Rio Grande (Rio Bravo, Indus, and Murray-Darling River Basins--can include complete desiccation during dry seasons, decimation of aquatic biodiversity, and substantial economic disruption.

  17. Fish species diversity in the Victoria and Kyoga lake basins: their conservation and sustainable use

    OpenAIRE

    2000-01-01

    Introduction of exotic fish species especially the Nile perch Lates niloticus, is believed to be responsible for the decline of fish species diversity in lakes Victoria, Kyoga and Nabugabo.About 60% of the haplochromine cichlids are thought to have become extinct from L. Victoria due to predation by the Nile perch. However there are many lakes satelite to the lakes Victoria and Kyoga basins which still have fish fauna similar to that of the main lakes. many of the satellite lakes are separate...

  18. The Blues of David Lynch

    OpenAIRE

    Roche, David

    2009-01-01

    This article is an attempt to elaborate a typology of the color blue in the color films of David Lynch up to and including Mulholland Drive (2001). The color blue is considered alternately as light, matter or verbal language. The author studies the use, function, value and meaning of blue lighting, divided into static and flashing light, and of the blue objects in Blue Velvet (1986) and Mulholland Drive. The author shows how Lynch appropriates connotations Western culture, under the influence...

  19. Time Series Models Adoptable for Forecasting Nile Floods and Ethiopian Rainfalls.

    Science.gov (United States)

    El-Fandy, M. G.; Taiel, S. M. M.; Ashour, Z. H.

    1994-01-01

    Long-term rainfall forecasting is used in making economic and agricultural decisions in many countries. It may also be a tool in minimizing the devastation resulting from recurrent droughts. To be able to forecast the total annual rainfall or the levels of seasonal floods, a class of models has first been chosen. The model parameters have then been estimated with an appropriate parameter estimation algorithm. Finally, diagnostic tests have been performed to verify the adequacy of the model. These are the general principles of system identification, which is the most crucial part of the forecasting procedure. In this paper several sets of data have been studied using different statistical procedures. The examined data include a historical 835-year record representing the levels of the seasonal Nile floods in Cairo, Egypt, during the period A.D. 622-1457. These readings were originally carried out by the Arabsto a great degree of accuracy in order to be used in estimating yearly taxes or Zacat (islamic duties). The observations also comprise recent total annual rainfall data over Addis Ababa (Ethiopia) (1907-1984), the total annual discharges of Ethiopian rivers (including the river Sobat discharges at Hillet Doleib, Blue Nile discharge at Roseris, river Dinder, river Rahar, and river Atbara), equatorial lake plateau supply as contributed at Aswan during the period 1912-1982, and the total annual discharges at Aswan during the period 1871-1982. Periodograms have been used to uncover possible peridodicities. Trends of rainfall and discharges of some rivers of east and central Africa have been also estimated.Using the first half of the available record, two autoregressive integrated moving average (ARIMA) time series models have been identified, one for the levels of the seasonal Nile floods in Cairo, the second to model the annual rainfall over Ethiopia. The time series models have been applied in 1-year-ahead forecasting to the other hall of the available record and

  20. [West Nile virus: a reality in Mexico].

    Science.gov (United States)

    Téllez, Ildefonso; Calderón, Oscar; Franco-Paredes, Carlos; del Río, Carlos

    2006-01-01

    West Nile virus (WNV) is a RNA virus of the Flaviridae, genus flavivirus family. It is a neuropathogenic virus causing disease in birds, horses and humans. WNVis transmitted by the vector mosquito Culex sp. The virus life 's cycle includes mosquitoes as vectors and birds as natural hosts. Humans are accidental hosts. Since the introduction of the Epidemiological Surveillance Program at the Ministry ofHealth. we have documented 90 positive test results among birds out of 1,223 cases studied in Mexico as of September IS. 2005. The incubation period in humans after a mosquito bite ranges from 3 to 14 days. Disease is characterized by early onset fever, general malaise, decreased appetite, nausea, vomiting, headaches, myalgias, enlarged lymph nodes andrash. Neurological manifestations include encephalitis andflaccid paralysis, which are present in less than 1% of subjects infected with WNV. Older patients display more adverse outcomes including death. The diagnosis is made by the determination of specific IgM and JgG antibodies in serum and/or cerebrospinal fluid. There is no antiviral treatment to date against WNV but interferon ?2b, and WNVspec4ic-immunoglobulin have been used Prevention is therefore the key to control the infection.

  1. The radiosensitivity of nile tilapia (Oreochromis niloticus) fingerlings

    International Nuclear Information System (INIS)

    The nile tilapia (Oreochromis niloticus), a very popular fish commercially in the Philippines, was studied to determine its radiosensitivity and to see its potential as a biological indicator in aquatic ecosystems. Nile tilapia was seen to be radiosensitive. The fish were exposed to gamma-irradiation and chromosomal aberrations were induced. The various types of aberrations seen were chromatid gaps, chromosome gaps, chromatid fragments, dicentric rings, fusions, despiralizations and translocations. Among the aberrations observed, dicentric rings, fusions and chromosome gaps were strongly correlated with dosage, with only the dicentric rings increasing steadily with increasing dosage. In the course of the study, the lethal dosage50 for nile tilapia with 18 days was determined and it was observed at 2.0 krad. The modal chromosome number was also established at 2n=44 with a karyotype exhibiting 22 pairs of acrocentric chromosomes with 2 pairs of marker chromosomes present. (Author)

  2. Beyond Deep Blue

    CERN Document Server

    Newborn, Monty

    2011-01-01

    More than a decade has passed since IBM's Deep Blue computer stunned the world by defeating Garry Kasparov, the world chess champion at that time. Beyond Deep Blue tells the continuing story of the chess engine and its steady improvement. The book provides analysis of the games alongside a detailed examination of the remarkable technological progress made by the engines - asking which one is best, how good is it, and how much better can it get. Features: presents a total of 118 games, played by 17 different chess engines, collected together for the first time in a single reference; details the

  3. A Blue Lagoon Function

    DEFF Research Database (Denmark)

    Markvorsen, Steen

    2007-01-01

    We consider a specific function of two variables whose graph surface resembles a blue lagoon. The function has a saddle point $p$, but when the function is restricted to any given straight line through $p$ it has a {\\em{strict local minimum}} along that line at $p$.......We consider a specific function of two variables whose graph surface resembles a blue lagoon. The function has a saddle point $p$, but when the function is restricted to any given straight line through $p$ it has a {\\em{strict local minimum}} along that line at $p$....

  4. The Blue Collar Brain

    Directory of Open Access Journals (Sweden)

    Guy eVan Orden

    2012-06-01

    Full Text Available Much effort has gone into elucidating control of the body by the brain, less so the role of the body in controlling the brain. This essay develops the idea that the brain does a great deal of work in the service of behavior that is controlled by the body, a blue collar role compared to the white collar control exercised by the body. The argument that supports a blue collar role for the brain is also consistent with recent discoveries clarifying the white collar role of synergies across the body's tensegrity structure, and the evidence of critical phenomena in brain and behavior.

  5. [Two imported cases of West Nile fever in Denmark].

    Science.gov (United States)

    Knudsen, Troels Bygum; Wilcke, Jon Torgny R; Andersen, Ove

    2003-05-01

    In the light of the current American epidemic, and since West Nile fever (WNF) has never previously been reported in Denmark, we describe two cases imported from Israel and Canada, respectively. WNF was diagnosed in a 46-year-old Danish tourist returning from Israel and a visiting 73-year-old Canadian citizen with Danish ancestry. The former manifested itself clinically as a mild flu-like illness, the latter as serious infection of the central nervous system. Thus, in addition to representing a rare case of West Nile encephalitis, it also constitutes one of the first reported cases of human infection of Canadian origin. PMID:12795078

  6. Dynamics of wind setdown at Suez and the Eastern Nile Delta.

    Directory of Open Access Journals (Sweden)

    Carl Drews

    Full Text Available BACKGROUND: Wind setdown is the drop in water level caused by wind stress acting on the surface of a body of water for an extended period of time. As the wind blows, water recedes from the upwind shore and exposes terrain that was formerly underwater. Previous researchers have suggested wind setdown as a possible hydrodynamic explanation for Moses crossing the Red Sea, as described in Exodus 14. METHODOLOGY/PRINCIPAL FINDINGS: This study analyzes the hydrodynamic mechanism proposed by earlier studies, focusing on the time needed to reach a steady-state solution. In addition, the authors investigate a site in the eastern Nile delta, where the ancient Pelusiac branch of the Nile once flowed into a coastal lagoon then known as the Lake of Tanis. We conduct a satellite and modeling survey to analyze this location, using geological evidence of the ancient bathymetry and a historical description of a strong wind event in 1882. A suite of model experiments are performed to demonstrate a new hydrodynamic mechanism that can cause an angular body of water to divide under wind stress, and to test the behavior of our study location and reconstructed topography. CONCLUSIONS/SIGNIFICANCE: Under a uniform 28 m/s easterly wind forcing in the reconstructed model basin, the ocean model produces an area of exposed mud flats where the river mouth opens into the lake. This land bridge is 3-4 km long and 5 km wide, and it remains open for 4 hours. Model results indicate that navigation in shallow-water harbors can be significantly curtailed by wind setdown when strong winds blow offshore.

  7. Blue-green algae

    Science.gov (United States)

    ... for 6 months relieves allergy symptoms in adults. Arsenic poisoning. Early research shows that taking a combination of blue-green algae and zinc by mouth twice daily for 12 weeks reduces arsenic levels and its effects on the skin in ...

  8. The Blue Denmark

    DEFF Research Database (Denmark)

    Hansen, Carsten Ørts; Sornn-Friese, Henrik

    This paper makes an important contribution to the discussion about knowledge based localised externalities in the context of shipping and the maritime sector in Denmark. In the paper we ask if there is a national, knowledge‐based maritime cluster configured around the shipowners in Denmark. This ...... talk about The Blue Denmark....

  9. The "Blue Banana" Revisited

    NARCIS (Netherlands)

    Faludi, A.K.F.

    2015-01-01

    This essay is about the “Blue Banana”. Banana is the name given subsequently by others to a Dorsale européenne (European backbone) identified empirically by Roger Brunet. In a background study to the Communication of the European Commission ‘Europe 2000’, Klaus Kunzmann and Michael Wegener put forwa

  10. Human Streptococcus agalactiae Isolate in Nile Tilapia (Oreochromis niloticus)

    OpenAIRE

    Evans, Joyce J.; Klesius, Phillip H.; Pasnik, David J.; Bohnsack, John F.

    2009-01-01

    Streptococcus agalactiae, the Lancefield group B streptococcus (GBS) long recognized as a mammalian pathogen, is an emerging concern with regard to fish. We show that a GBS serotype Ia multilocus sequence type ST-7 isolate from a clinical case of human neonatal meningitis caused disease and death in Nile tilapia (Oreochromis niloticus).

  11. Heritability of cold tolerance in Nile tilapia, Oreochromis niloticus, juveniles

    NARCIS (Netherlands)

    Charo-Karisa, H.; Rezk, M.A.; Bovenhuis, H.; Komen, J.

    2005-01-01

    The inability of tilapia to tolerate low temperatures is of major economic concern as it reduces their growing season and leads to over winter mortality. In this study, cold tolerance of juvenile Nile tilapia, Oreochromis niloticus, was investigated and heritability estimates obtained. A total of 80

  12. The Buzz-z-z on West Nile Virus

    Centers for Disease Control (CDC) Podcasts

    2012-01-12

    In this podcast for kids, the Kidtastics talk about West Nile Virus and how to protect yourself from it.  Created: 1/12/2012 by Centers for Disease Control and Prevention (CDC).   Date Released: 1/12/2012.

  13. Clinical sentinel surveillance of equine West Nile fever, Spain

    DEFF Research Database (Denmark)

    Saegerman, C.; Alba-Casals, A.; García-Bocanegra, I.;

    2016-01-01

    West Nile fever (WNF) is a viral zoonotic infection caused by a mosquito-borne flavivirus of the Flaviviridae family. According to a comparative study, the passive surveillance of horses by equine veterinarians appeared to be the most cost-effective system in the European context of WNF. Clinical...

  14. Breeding for improved production of Nile tilapia (Oreochromis niloticus L.)

    NARCIS (Netherlands)

    Rutten, M.J.M.

    2005-01-01

    The aim of this thesis was to generate knowledge that supports the design of breeding programs for Nile tilapia targeting genetic improvement of body weight and fillet yield to serve the European market. To this end, both the genetic variation and the performance levels of different strains of tilap

  15. Purpura fulminans associated with acute West Nile virus encephalitis.

    Science.gov (United States)

    Shah, Sheevam; Fite, Laura Paul; Lane, Natalie; Parekh, Palak

    2016-02-01

    Purpura fulminans is a progressive thrombotic disorder that presents with widespread purpura due to deficiency or dysfunction of protein C or protein S. Lesions present as well-demarcated erythematous macules that progress to irregular areas of hemorrhagic necrosis.West Nile virus is a member of the Flaviviridae family transmitted to humans through the bite of various mosquito species. It manifests as West Nile fever in 25% of those infected and less commonly as neuroinvasive disease. An African American man in his fortiespresented with altered mental status and was noted to have evidence of disseminated intravascular coagulation according to his lab data. He then developed dusky skin discoloration and systemic flaccid bullae with desquamation. Biopsy was consistent with purpura fulminans and the patient eventually developed symmetric peripheral gangrene, requiring amputations of all four extremities. Infectious work up revealed positive testing for IgM and IgG antibodies in serum and cerebrospinal fluid leading to the diagnosis of acute West Nile Virus encephalitis. We present this case to describe the rarely reported association of purpura fulminans with West Nile Virus infection.

  16. Holocene evolution of the River Nile drainage system as revealed from the Lake Dendi sediment record, central Ethiopian highlands

    Science.gov (United States)

    Wagner, B.; Viehberg, F. A.; Wennrich, V.; Junginger, A.; Kolvenbach, A.; Rethemeyer, J.; Schaebitz, F.; Schmiedl, G. H.

    2015-12-01

    A 12 m long sediment sequence from Dendi Crater lakes, located on the central Ethiopian Plateau, was analysed with sedimentological and geochemical methods to reconstruct the regional environmental history. Bulk organic carbon samples from 23 horizons throughout the sequence were used for AMS radiocarbon dating and indicate that the sediment sequence spans the last ca. 12 cal kyr BP. Microscope analyses and sedimentological data reveal three tephra layers, of which the most prominent layer with a thickness of ~2 m was deposited at 10.2 cal kyr BP and probably originates from an eruption of the Wenchi crater 12 km to the west of the Dendi lakes. Sedimentological data of the pelagic deposits indicate shifts in erosion and rainfall throughout the record. A decrease in Ca and Sr at 11.6 cal kyr BP is related to the shift of less humid condition during the Younger Dryas (YD) to the return to full humid conditions of the African Humid Period (AHP). Single thin horizons with high carbonate content or high Ti and K imply that short spells of dry conditions and significantly increased rainfall superimpose the generally more humid conditions during the AHP. The end of the AHP is gradual. Relatively stable and less humid conditions characterised the Dendi Crater lakes until around 3.9 cal kyr BP. A highly variable increase in clastic matter over the last 1500 years indicates higher erosion due to short-term variations in precipitation within the Dendi catchment. Overall, the sediment record suggests moderate change of precipitation during the Holocene, which is probably due to their exposed location in the Ethiopian highlands. The data from the Dendi Crater lakes show, in concert with other records from the Nile catchment and the Eastern Mediterranean Sea (EMS), that the Blue Nile provided the main freshwater source for maintaining EMS stratification and sapropel S1 formation between ca. 10.0 and 8.7 cal kyr BP. Subsequent aridification is recorded from equatorial East Africa

  17. The Blue Emu

    Science.gov (United States)

    Descalzi, Doug; Gillett, John; Gordon, Carlton; Keener, ED; Novak, Ken; Puente, Laura

    1993-01-01

    The primary goal in designing the Blue Emu was to provide an airline with a cost efficient and profitable means of transporting passengers between the major cities in Aeroworld. The design attacks the market where a demand for inexpensive transportation exists and for this reason the Blue Emu is an attractive investment for any airline. In order to provide a profitable aircraft, special attention was paid to cost and economics. For example, in manufacturing, simplicity was stressed in structural design to reduce construction time and cost. Aerodynamic design employed a tapered wing which reduced the induced drag coefficient while also reducing the weight of the wing. Even the propulsion system was selected with cost effectiveness in mind, yet also to maintain the marketability of the aircraft. Thus, in every aspect of the design, consideration was given to economics and marketability of the final product.

  18. Synthesizing a Blue Ocean

    OpenAIRE

    Vester, Daniel

    2012-01-01

    The purpose of this Master thesis was to determine how electronic musical instrument companies could utilize innovation strategies to add value to their products and create new business markets beyond their core. The theoretical framework was established by outlining competitive strategies suitable for adoption by electronic musical instrument companies. The Blue Ocean Strategy was compared to traditional competitive strategies such as Porter’s Five Forces, and subsequently chosen because of ...

  19. Abundance, distribution and population trends of Nile crocodile (Crocodylus niloticus) in Gonarezhou National Park, Zimbabwe

    OpenAIRE

    Zisadza-Gandiwa, P.; Gandiwa, E.; Jakarasi, J.; Westhuizen, van der, H.; Muvengwi, J.

    2013-01-01

    The Nile crocodile (Crocodylus niloticus) is an iconic or keystone species in many aquatic ecosystems. In order to understand the abundance, distribution, and population trends of Nile crocodiles in Gonarezhou National Park (GNP), southeastern Zimbabwe, we carried out 4 annual aerial surveys, using a Super Cub aircraft, along 3 major rivers, namely, Save, Runde and Mwenezi, between 2008 and 2011. Our results show that Runde River was characterised by a significant increase in Nile crocodile a...

  20. Water Resources in Lake Tana Basin: Statistical Analysis of Hydrological and Meteorological Time Series

    Science.gov (United States)

    Tigabu, T. B.; Hörmann, G.; Fohrer, N.

    2015-12-01

    Nowadays, time series environmental flow analysis is becoming one of the most important tasks in ecohydrology in order to design process based system solutions. Thus, the purpose of this research paper was to understand temporal and spatial variability of stream flows, rainfall, and inflows and outflows to and from the Lake Tana basin. Autocorrelation and cross correlation tests were applied for the long years' daily stream flows and rainfall using R languages. These methods were used to see how the stream flow or rainfall data were serially correlated and rainfall, stream flow and lake level time series data were cross correlated with each other. Autocorrelation tests of daily rainfall were carried out for many rainfall stations and the outputs indicate that there are no spikes showing significant seasonal signals. The annual rainfall map was produced for the whole catchment based on long years' records at different stations inside the catchment using inverse distance weighted interpolation (IDW) method in the GIS environment. Based on this map there is high spatial variability of annual rainfall in the catchment. The average maximum, minimum and mean annual rainfall values are 1506.4, 798.7, and 1238.1 mm respectively. According to the cross correlation tests done for stream flow & rainfall, better correlations were observed after 15 to 30 days lag time due to late response of the catchment for runoff generation. The study also prevailed that the Lake Tana water level and Blue Nile discharge at Bahir Dar station have positive cross correlation with maximum value at time lag of zero. There is a dramatic drop in the lake level and stream flow volume at the same location since 2000 due to human induced local climate forcing. In general, this research indicates that there is high temporal and spatial variability in rainfall, Lake water level and stream flows.

  1. Analysis of the influence of tectonics on the evolution valley network based on the SRTM DEM and the relationship of automatically extracted lineaments and the tectonic faults, Jemma River basin, Ethiopia

    Science.gov (United States)

    Kusák, Michal

    2016-04-01

    The Ethiopian Highland is good example of high plateau landscape formed by combination of tectonic uplift and episodic volcanism (Kazmin, 1975; Pik et al., 2003; Gani et al., 2009). Deeply incised gorges indicate active fluvial erosion which leads to instabilities of over-steepened slopes. In this study we focus on Jemma River basin which is a left tributary of Abay - Blue Nile to assess the influence of neotectonics on the evolution of its river and valley network. Tectonic lineaments, shape of valley networks, direction of river courses and intensity of fluvial erosion were compared in six subregions which were delineate beforehand by means of morphometric analysis. The influence of tectonics on the valley network is low in the older deep and wide canyons and in the and on the high plateau covered with Tertiary lava flows while younger upper part of the canyons it is high. Furthermore, the coincidence of the valley network with the tectonic lineaments differs in the subregions. The fluvial erosion along the main tectonic zones (NE-SW) direction made the way for backward erosion possible to reach far distant areas in E for the fluvial erosion. This tectonic zone also separates older areas in the W from the youngest landscape evolution subregions in the E, next to the Rift Valley. We studied the functions that can automatically extract lineaments in programs ArcGIS 10.1 and PCI Geomatica. The values of input parameters and their influence of the final shape and number of lineaments. A map of automated extracted lineaments was created and compared with 1) the tectonic faults by Geology Survey of Ethiopia (1996); and 2) the lineaments based on visual interpretation of by the author. The comparation of lineaments by automated visualization in GIS and visual interpretation of lineaments by the author proves that both sets of lineaments are in the same azimuth (NE-SW) - the same direction as the orientation of the rift. But it the mapping of lineaments by automated

  2. Estruturas fundamentais no blues

    OpenAIRE

    Silva, Rafael Palmeira da

    2012-01-01

    Resumo: Esta pesquisa tem como objeto de estudo a aplicação e adaptação da teoria de Schenker como ferramenta analítica aplicada ao jazz, tendo em vista a possibilidade de encontrar estruturas fundamentais distintas na música popular. Tendo como base as análises feitas por Larson (1998; 2009), Forte (2011) e Stock (1993) a pesquisa abordará, em um primeiro momento, as origens do jazz (blues e ragtime) como parte essencial para sua abordagem analítica, através da ótica etno-schenkeriana propos...

  3. Recent progress in West Nile virus diagnosis and vaccination

    Directory of Open Access Journals (Sweden)

    De Filette Marina

    2012-03-01

    Full Text Available Abstract West Nile virus (WNV is a positive-stranded RNA virus belonging to the Flaviviridae family, a large family with 3 main genera (flavivirus, hepacivirus and pestivirus. Among these viruses, there are several globally relevant human pathogens including the mosquito-borne dengue virus (DENV, yellow fever virus (YFV, Japanese encephalitis virus (JEV and West Nile virus (WNV, as well as tick-borne viruses such as tick-borne encephalitis virus (TBEV. Since the mid-1990s, outbreaks of WN fever and encephalitis have occurred throughout the world and WNV is now endemic in Africa, Asia, Australia, the Middle East, Europe and the Unites States. This review describes the molecular virology, epidemiology, pathogenesis, and highlights recent progress regarding diagnosis and vaccination against WNV infections.

  4. Clinical Manifestations and Outcomes of West Nile Virus Infection

    Directory of Open Access Journals (Sweden)

    James J. Sejvar

    2014-02-01

    Full Text Available Since the emergence of West Nile virus (WNV in North America in 1999, understanding of the clinical features, spectrum of illness and eventual functional outcomes of human illness has increased tremendously. Most human infections with WNV remain clinically silent. Among those persons developing symptomatic illness, most develop a self-limited febrile illness. More severe illness with WNV (West Nile neuroinvasive disease, WNND is manifested as meningitis, encephalitis or an acute anterior (polio myelitis. These manifestations are generally more prevalent in older persons or those with immunosuppression. In the future, a more thorough understanding of the long-term physical, cognitive and functional outcomes of persons recovering from WNV illness will be important in understanding the overall illness burden.

  5. Seasonal and geographic variation of southern blue whale subspecies in the Indian ocean.

    OpenAIRE

    Flore Samaran; Stafford, Kathleen M.; Branch, Trevor A.; Jason Gedamke; Jean-Yves Royer; Dziak, Robert P.; Christophe Guinet

    2013-01-01

    International audience Understanding the seasonal movements and distribution patterns of migratory species over ocean basin scales is vital for appropriate conservation and management measures. However, assessing populations over remote regions is challenging, particularly if they are rare. Blue whales (Balaenoptera musculus spp) are an endangered species found in the Southern and Indian Oceans. Here two recognized subspecies of blue whales and, based on passive acoustic monitoring, four "...

  6. Blue ocean leadership.

    Science.gov (United States)

    Kim, W Chan; Mauborgne, Renée

    2014-05-01

    Ten years ago, two INSEAD professors broke ground by introducing "blue ocean strategy," a new model for discovering uncontested markets that are ripe for growth. In this article, they apply their concepts and tools to what is perhaps the greatest challenge of leadership: closing the gulf between the potential and the realized talent and energy of employees. Research indicates that this gulf is vast: According to Gallup, 70% of workers are disengaged from their jobs. If companies could find a way to convert them into engaged employees, the results could be transformative. The trouble is, managers lack a clear understanding of what changes they could make to bring out the best in everyone. Here, Kim and Mauborgne offer a solution to that problem: a systematic approach to uncovering, at each level of the organization, which leadership acts and activities will inspire employees to give their all, and a process for getting managers throughout the company to start doing them. Blue ocean leadership works because the managers' "customers"-that is, the people managers oversee and report to-are involved in identifying what's effective and what isn't. Moreover, the approach doesn't require leaders to alter who they are, just to undertake a different set of tasks. And that kind of change is much easier to implement and track than changes to values and mind-sets. PMID:24956870

  7. Blue ocean leadership.

    Science.gov (United States)

    Kim, W Chan; Mauborgne, Renée

    2014-05-01

    Ten years ago, two INSEAD professors broke ground by introducing "blue ocean strategy," a new model for discovering uncontested markets that are ripe for growth. In this article, they apply their concepts and tools to what is perhaps the greatest challenge of leadership: closing the gulf between the potential and the realized talent and energy of employees. Research indicates that this gulf is vast: According to Gallup, 70% of workers are disengaged from their jobs. If companies could find a way to convert them into engaged employees, the results could be transformative. The trouble is, managers lack a clear understanding of what changes they could make to bring out the best in everyone. Here, Kim and Mauborgne offer a solution to that problem: a systematic approach to uncovering, at each level of the organization, which leadership acts and activities will inspire employees to give their all, and a process for getting managers throughout the company to start doing them. Blue ocean leadership works because the managers' "customers"-that is, the people managers oversee and report to-are involved in identifying what's effective and what isn't. Moreover, the approach doesn't require leaders to alter who they are, just to undertake a different set of tasks. And that kind of change is much easier to implement and track than changes to values and mind-sets.

  8. Blue emitting undecaplatinum clusters

    Science.gov (United States)

    Chakraborty, Indranath; Bhuin, Radha Gobinda; Bhat, Shridevi; Pradeep, T.

    2014-07-01

    A blue luminescent 11-atom platinum cluster showing step-like optical features and the absence of plasmon absorption was synthesized. The cluster was purified using high performance liquid chromatography (HPLC). Electrospray ionization (ESI) and matrix assisted laser desorption ionization (MALDI) mass spectrometry (MS) suggest a composition, Pt11(BBS)8, which was confirmed by a range of other experimental tools. The cluster is highly stable and compatible with many organic solvents.A blue luminescent 11-atom platinum cluster showing step-like optical features and the absence of plasmon absorption was synthesized. The cluster was purified using high performance liquid chromatography (HPLC). Electrospray ionization (ESI) and matrix assisted laser desorption ionization (MALDI) mass spectrometry (MS) suggest a composition, Pt11(BBS)8, which was confirmed by a range of other experimental tools. The cluster is highly stable and compatible with many organic solvents. Electronic supplementary information (ESI) available: Details of experimental procedures, instrumentation, chromatogram of the crude cluster; SEM/EDAX, DLS, PXRD, TEM, FT-IR, and XPS of the isolated Pt11 cluster; UV/Vis, MALDI MS and SEM/EDAX of isolated 2 and 3; and 195Pt NMR of the K2PtCl6 standard. See DOI: 10.1039/c4nr02778g

  9. The Holocene Geoarchaeology of the Desert Nile in Northern Sudan

    Science.gov (United States)

    Woodward, Jamie; Macklin, Mark; Spencer, Neal; Welsby, Derek; Dalton, Matthew; Hay, Sophie; Hardy, Andrew

    2016-04-01

    Invited Paper Forty years ago Colin Renfrew declared that "every archaeological problem starts as a problem in geoarchaeology" (Renfrew, 1976 p. 2). With this assertion in mind, this paper draws upon the findings from field research in two sectors of the Nile Valley of Northern Sudan dedicated to the exploration of human-environment interactions during the middle and late Holocene. This part of the Nile corridor contains a rich cultural record and an exceptionally well preserved Holocene fluvial archive. A distinctive feature of these records is the variety of evidence for interaction between desert and river over a range of spatial and temporal scales. This interaction presented both challenges and opportunities for its ancient inhabitants. This paper will present evidence for large-scale landscape changes driven by shifts in global climate. It will also show how we have integrated the archaeological and geological records in the Northern Dongola Reach and at Amara West - where long-term field projects led by archaeologists from the British Museum have recognised the importance of a sustained commitment to interdisciplinary research to achieve a fully integrated geoarchaeological approach across a range of scales. The former project is a large-scale landscape survey with multiple sites across an 80 km reach of the Nile whilst the latter has a strong focus on a single New Kingdom town site and changes in its environmental setting. By combining multiple archaeological and geological datasets - and pioneering the use of OSL dating and strontium isotope analysis in the Desert Nile - we have developed a new understanding of human responses to Holocene climate and landscape change in this region. Renfrew, C. (1976) Archaeology and the earth sciences. In: D.A. Davidson and M.I. Shackley (eds) Geoarchaeology: Earth Science and the Past, Duckworth, London, 1-5.

  10. The resurgence of lymphatic filariasis in the Nile delta.

    OpenAIRE

    Harb, M.; Faris, R; Gad, A. M.; Hafez, O. N.; Ramzy, R.; Buck, A. A.

    1993-01-01

    A study of 325,000 residents of 314 villages in six governorates of the Nile delta area of Egypt revealed that the prevalence of lymphatic filariasis increased from 20% in 1991, especially in the governorates of Qalyubiya, Monufiya, Dakhaliya, and Giza. The distribution of the communites with endemic filariasis is focal. Clusters of villages with high prevalences are surrounded by others in which the disease is absent, although their environmental, social, and agricultural f...

  11. Postpartum Blues and Postpartum Depression

    Directory of Open Access Journals (Sweden)

    Erdem Ö et al.

    2009-09-01

    Full Text Available Postpartum blues which is seen during the postpartum period is a transient psychological state. Most of the mothers experience maternity blues in postpartum period. It remains usually unrecognized by the others. Some sensitive families can misattribute these feelings as depression. In this article, we tried to review the characteristics of maternity blues and its differences from depression. We defined depression and presented the incidence and diagnostic criteria, of major depression as well as the risk factors and clinic findings of postpartum depression. Thus, especially at primary care we aimed to prevent misdiagnosis of both maternity blues and depression

  12. Blue Mountains Ecoregion: Chapter 16 in Status and trends of land change in the Western United States--1973 to 2000

    Science.gov (United States)

    Soulard, Christopher E.

    2012-01-01

    The Blue Mountains Ecoregion encompasses approximately 65,461 km² (25,275 mi²) of land bordered on the north by the Columbia Plateau Ecoregion, on the east by the Northern Rockies Ecoregion, on the south by the Snake River Basin and the Northern Basin and Range Ecoregions, and on the west by the Cascades and the Eastern Cascades Slopes and Foothills Ecoregions (fig. 1) (Omernik, 1987; U.S. Environmental Protection Agency, 1997). Most of the Blue Mountains Ecoregion is located within Oregon (83.5 percent); 13.8 percent is in Idaho, and 2.7 percent is in Washington. The Blue Mountains are composed of primarily Paleozoic volcanic rocks, with minor sedimentary, metamorphic, and granitic rocks. Lower mountains and numerous basin-and-range areas, as well as the lack of Quaternary-age volcanoes, distinguish the Blue Mountains from the adjacent Cascade Range (Thorson and others, 2003).

  13. Seroconversion for west Nile and St. Louis encephalitis viruses among sentinel horses in Colombia

    Directory of Open Access Journals (Sweden)

    Salim Mattar

    2011-12-01

    Full Text Available We prospectively sampled flavivirus-naïve horses in northern Colombia to detect West Nile virus (WNV and St. Louis encephalitis virus (SLEV seroconversion events, which would indicate the current circulation of these viruses. Overall, 331 (34.1% of the 971 horses screened were positive for past infection with flaviviruses upon initial sampling in July 2006. During the 12-month study from July 2006-June 2007, 33 WNV seroconversions and 14 SLEV seroconversions were detected, most of which occurred in the department of Bolivar. The seroconversion rates of horses in Bolivar for the period of March-June 2007 reached 12.4% for WNV and 6.7% for SLEV. These results comprise the first serologic evidence of SLEV circulation in Colombia. None of the horses sampled developed symptoms of encephalitis within three years of initial sampling. Using seroconversions in sentinel horses, we demonstrated an active circulation of WNV and SLEV in northern Colombia, particularly in the department of Bolivar. The absence of WNV-attributed equine or human disease in Colombia and elsewhere in the Caribbean Basin remains a topic of debate and speculation.

  14. Trace metal concentrations in Nile tilapia (Oreochromis niloticus) in three catchments, Sri Lanka.

    Science.gov (United States)

    Allinson, G; Salzman, S A; Turoczy, N; Nishikawa, M; Amarasinghe, U S; Nirbadha, K G S; De Silva, S S

    2009-03-01

    Samples of the muscle and liver of the Nile tilapia (Oreochromis niloticus) were obtained from a single reservoir in each of three Sri Lankan catchments (Kaudulla, Rajanganaya, and Udawalawe reservoirs in the Mahaweli, Kala Oya, and Walawe Ganga river basins, respectively) in 2002. The concentrations of 12 elements were consistently detected in the tilapia muscle and liver (Ca, Cd, Cu, Fe, Hg, K, Mg, Mn, Na, P, Sr and Zn). However, a three factorial principal components analysis suggested that there were no differences in the metal profiles (range of elements and concentration) of the fish obtained from any of the three reservoirs, although the chemistries of each tissue (muscle and liver) were different. Metal concentrations were below WHO and Food Standards Australia and New Zealand guideline values, and substantial quantities of tilapia would need to be consumed each week on a regular basis to exceed intake limits (e.g. more than 1.5 kg to exceed intake lits for Cu), suggesting consumption of tilapia from these reservoirs poses little risk to human health. PMID:18949439

  15. The role of satellite lakes in conservation of fish species diversity in the Lake Kyoga basin

    OpenAIRE

    Ogutu-Ohwayo, R.; Wandera, S.B.; Namulemo, G.; Mbabazi, D.

    1999-01-01

    Lakes Victoria and Kyoga had, a diverse fish fauna, which was important as food for local population and valuable in scientific studies. Over the past twenty years, the diversity of fish in these lakes had declined due to over-exploitation, introduction of new fish species including the piscivorous Nile perch and degradation of fish habitat. Studies of satellite lakes in the Victoria and Kyoga lake basins suggested that some of these lakes harboured species which had been lost from the mai...

  16. Localization of West Nile Virus in monkey brain: double staining antigens immunohistochemically of neurons, neuroglia cells and West Nile Virus

    OpenAIRE

    He, Xianli; Ren, Junping; Xu, Fangling; Ferguson, Monique R; Li, Guangyu

    2009-01-01

    West Nile virus (WNV) can cause encephalitis or meningitis that affects brain tissue, which can also lead to permanent neurological damage that can be fatal. To our knowledge, no consistent double immunohistochemical staining of neurons, neuroglia cells, and WNV has yet been reported. To establish a method for performing double-label immunohistochemical detection of neurons, neuroglia cells and WNV, examining the pathological characteristics of WNV-infected neurons, neuroglia cells, and inves...

  17. Tracing of the defunct Canopic Nile branch using geoelectrical resistivity data around Itay El-Baroud area, Nile Delta, Egypt

    International Nuclear Information System (INIS)

    Around the Nile Delta Branches, ancient settlements had been created and left their remains to be good witness for the paleoenvironment during the Holocene time. Therefore, tracing of the defunct Canopic branch and its distributaries as well as associated environments are of great importance. Using a Schlumberger electrode configuration, well-distributed 44 vertical electrical resistivity soundings were acquired. The 1D modelling technique was applied to estimate the depth and the apparent resistivity of the interpreted geoelectrical units. Then 2D inversion was applied for the same data set using the ABIC least-squares inversion scheme. The geoelectrical cross-sections and slice maps discriminate the Upper Quaternary sequence into three geoelectrical units. The Holocene Nile mud is represented by two units: the agricultural root zone (unit 1) that is underlain by relatively thick water-saturated mud (unit 2). The Upper Pleistocene sandy aquifer is represented by irregular surface (unit 3). Two generations of defunct channels were traced out. The older channels are characterized by low sinuosity compared with younger channels. This is probably attributed to river activity due to relatively low sea level and much higher Nile discharge. The system of younger channels is characterized by broad meanders, probably as a consequence of sea-level rise and decreased gradient since the Middle Holocene

  18. Instant BlueStacks

    CERN Document Server

    Judge, Gary

    2013-01-01

    Get to grips with a new technology, understand what it is and what it can do for you, and then get to work with the most important features and tasks. A fast-paced, example-based approach guide for learning BlueStacks.This book is for anyone with a Mac or PC who wants to run Android apps on their computer. Whether you want to play games that are freely available for Android but not your computer, or you want to try apps before you install them on a physical device or use it as a development tool, this book will show you how. No previous experience is needed as this is written in plain English

  19. Edwardsiella ictaluri as the causative agent of mortality in cultured Nile tilapia

    Science.gov (United States)

    Edwardsiella ictaluri was consistently isolated from the spleens, livers, and head kidneys of diseased Nile tilapia Oreochromis niloticus from a farm experiencing mortality events in several culture ponds. We describe the first published outbreak of E. ictaluri–induced Edwardsiellosis in Nile tilapi...

  20. Complete Genome Sequence of Streptococcus agalactiae Strain S25 Isolated from Peritoneal Liquid of Nile Tilapia

    Science.gov (United States)

    Mainardi, Rafaella Menegheti; Lima Júnior, Edson Antônio; Ribeiro Júnior, Jose Carlos; Beloti, Vanerli; Carmo, Anderson Oliveira; Kalapothakis, Evanguedes; Gonçalves, Daniela Dib; Padua, Santiago Benites

    2016-01-01

    Streptococcus agalactiae (Lancefield group B; GBS) is one of the major pathogens in fish production, especially in Nile tilapia (Oreochromis niloticus). The genomic characteristics of GBS isolated from fish must be more explored. Thus, we present here the genome of GBS S25, isolated from Nile tilapia from Brazil. PMID:27491974

  1. Risk assessment on severe hazards to China caused by West Nile virus

    Institute of Scientific and Technical Information of China (English)

    CHEN Jiming; SUN Yingxue; WANG Zhiliang; SHEN Chaojian; XIE Zhonglun; WANG Ximing

    2004-01-01

    Recent West Nile virus epidemics in USA draw worldwide concerns. Here the basic biological and epidemiologicai features of the virus are analyzed along with the special immunity of humans and animals, the immigration of birds and the natural environments in China. The risk of severe hazards to China caused by West Nile virus is assessed not high thereafter.

  2. Complete Genome Sequence of Streptococcus agalactiae Strain S25 Isolated from Peritoneal Liquid of Nile Tilapia.

    Science.gov (United States)

    Mainardi, Rafaella Menegheti; Lima Júnior, Edson Antônio; Ribeiro Júnior, Jose Carlos; Beloti, Vanerli; Carmo, Anderson Oliveira; Kalapothakis, Evanguedes; Gonçalves, Daniela Dib; Padua, Santiago Benites; Pereira, Ulisses Pádua

    2016-01-01

    Streptococcus agalactiae (Lancefield group B; GBS) is one of the major pathogens in fish production, especially in Nile tilapia (Oreochromis niloticus). The genomic characteristics of GBS isolated from fish must be more explored. Thus, we present here the genome of GBS S25, isolated from Nile tilapia from Brazil. PMID:27491974

  3. West Nile Virus: What You Need to Know Now - August 2012

    Centers for Disease Control (CDC) Podcasts

    2012-08-21

    This podcast lists the states where most of the 2012 West Nile viruses have been reported and explains how people can protect themselves from West Nile virus.  Created: 8/21/2012 by .   Date Released: 8/21/2012.

  4. Explaining and forecasting interannual variability in the flow of the Nile River

    Science.gov (United States)

    Siam, M. S.; Eltahir, E. A. B.

    2014-05-01

    The natural interannual variability in the flow of Nile River had a significant impact on the ancient civilizations and cultures that flourished on the banks of the river. This is evident from stories in the Bible and Koran, and from the numerous Nilometers discovered near ancient temples. Here, we analyze extensive data sets collected during the 20th century and define four modes of natural variability in the flow of Nile River, identifying a new significant potential for improving predictability of floods and droughts. Previous studies have identified a significant teleconnection between the Nile flow and the Eastern Pacific Ocean. El Niño-Southern Oscillation (ENSO) explains about 25% of the interannual variability in the Nile flow. Here, we identify, for the first time, a region in the southern Indian Ocean with similarly strong teleconnection to the Nile flow. Sea Surface Temperature (SST) in the region (50-80° E and 25-35° S) explains 28% of the interannual variability in the Nile flow. During those years with anomalous SST conditions in both Oceans, we estimate that indices of the SSTs in the Pacific and Indian Oceans can collectively explain up to 84% of the interannual variability in the flow of Nile. Building on these findings, we use classical Bayesian theorem to develop a new hybrid forecasting algorithm that predicts the Nile flow based on global models predictions of indices of the SST in the Eastern Pacific and Southern Indian Oceans.

  5. Clinical West Nile virus infection in 2 horses in western Canada.

    Science.gov (United States)

    Abutarbush, Sameeh M; O'Connor, Brendan P; Clark, Chris; Sampieri, Francesca; Naylor, Jonathan M

    2004-04-01

    Two horses had a history of ataxia and weakness or recumbency. One recovered and was diagnosed with West Nile virus (WNV) infection by serologic testing. The other was euthanized; it had meningoencephalomyelitis, WNV was detected by polymerase chain reaction. West Nile virus infection is an emerging disease. Year 2002 is the first year in which cases have been seen in Saskatchewan.

  6. Abundance, distribution and population trends of Nile crocodile (Crocodylus niloticus) in Gonarezhou National Park, Zimbabwe

    NARCIS (Netherlands)

    Zisadza-Gandiwa, P.; Gandiwa, E.; Jakarasi, J.; Westhuizen, van der H.; Muvengwi, J.

    2013-01-01

    The Nile crocodile (Crocodylus niloticus) is an iconic or keystone species in many aquatic ecosystems. In order to understand the abundance, distribution, and population trends of Nile crocodiles in Gonarezhou National Park (GNP), southeastern Zimbabwe, we carried out 4 annual aerial surveys, using

  7. Mud volcano formation within the Western slope of the Nile Cone sourced from pre-salt layers

    Science.gov (United States)

    Kirkham, Christopher; Cartwright, Joseph; Hermanrud, Christian; Jebsen, Christopher

    2015-04-01

    Mud volcanos are prevalent in a variety of settings, particularly in those where rapid sedimentation, thrust loading or horizontal tectonic stresses are observed. Here we describe from a three-dimensional (3D) seismic survey located on the Western slope of the Nile Cone, a suite of mud volcanoes emplaced throughout the post-salt Pliocene-Recent succession. These mud volcanoes are highly variable in scale, some among the largest ever described. Extrusive volumes range from 100 km3. Evaporites are widely considered a world class seal which has given rise to the discovery of numerous pre-salt hydrocarbon accumulations. Pre-salt depletion features, contrasts in p-wave velocity and salt welding due to mud remobilisation, are all indicative of a pre-Messinian (sub-salt) primary mud source, predominantly Tortonian in age. This implies large scale mud remobilisation through the thick Messinian evaporite succession. It is our interpretation that the formation of mud volcanoes within this region is intimately related to the basinal hydrodynamics, which include undercompaction and subsequent fluid retention, local sea level variation and overpressure generation. These mechanisms are controlled by key events in the geological history of the basin such as the Messinian Salinity Crisis (MSC) and the Zanclean flood. We argue that the formation of these mud volcanoes is a direct response to overpressure generated primarily through rapid loading of pre-salt sediments during the MSC and catastrophic re-flooding during its immediate aftermath. Ultimately the location at which they form is associated with deeper features such as underlying faults and potential hydrocarbon plays. It is feasible that similar basin-scale remobilisation and overpressure could be expected for other salt basins world-wide that have undergone similar priming processes.

  8. Blue-sky thinking

    International Nuclear Information System (INIS)

    Global environmental problems - such as the greenhouse effect, the depletion of natural resources and the accumulation of wastes - have been recognized as common international issues affecting humanity since the 1990s. Sustainable development on a global scale is now sought, for instance, with the establishment of the targets for greenhouse gas reduction in the 1997 Kyoto Protocol, and with the adoption of the Declaration on Sustainable Development at the 2002 Johannesburg Summit. Honda launched the slogan 'Blue Sky for Children' in the 1960s when environmental pollution became a highly visible issue. During that decade we started an aggressive approach aimed at substantial environmental improvement, and unveiled the Compound Vortex Controlled Combustion (CVCC) engine - which used unique low-emission technology - in the United States and Japan. Since then, we have developed the Variable Valve Timing and Lift Electric Control System (VTEC) and the i-VTEC series with innovative engine technology, permitting global production of vehicles that combine high performance with state-of-the-art low-emission technologies. And we continued to work to preserve the global environment by releasing a hybrid vehicle, the Insight, which achieved the most efficient fuel consumption in the world at the time of its introduction in 1998

  9. Blue Man袭东京

    Institute of Scientific and Technical Information of China (English)

    Naomi Saeki; 李宝怡

    2008-01-01

    <正>20年前在美国曼克顿风靡一时的Blue Man Group,最近在东京出现,马上成为城中话题。在东京,每年有不少舞台剧演出,但是像Blue Man Group这样备受注目的,近年罕见。Blue Man Group in Tokyo于上年12月开始公演·1个月的门票早在9月中旬

  10. Blue Angel for green electronics

    Energy Technology Data Exchange (ETDEWEB)

    Boettcher-Tiedemann, C.; Jacobs, B. [Federal Environmental Agency, Berlin (Germany)

    2004-07-01

    The Blue Angel was the first eco-label worldwide. It has been in existence for 26 years. For the last 12 years, modern electronic office and communications equipment has been among the products that are eligible for award of the Blue Angel. The Blue Angel eco-label is an important element of integrated product policy and is aimed towards environmentally sound product design. In addition, health aspects are increasingly being taken into account in criteria development. The use of the label gives innovative companies better market opportunities for products so labelled. For consumers and for purchasers in businesses and public administrations, it gives valuable guidance for product purchase. (orig.)

  11. Thermal preference predicts animal personality in Nile tilapia Oreochromis niloticus.

    Science.gov (United States)

    Cerqueira, Marco; Rey, Sonia; Silva, Tome; Featherstone, Zoe; Crumlish, Margaret; MacKenzie, Simon

    2016-09-01

    Environmental temperature gradients provide habitat structure in which fish orientate and individual thermal choice may reflect an essential integrated response to the environment. The use of subtle thermal gradients likely impacts upon specific physiological and behavioural processes reflected as a suite of traits described by animal personality. In this study, we examine the relationship between thermal choice, animal personality and the impact of infection upon this interaction. We predicted that thermal choice in Nile tilapia Oreochromis niloticus reflects distinct personality traits and that under a challenge individuals exhibit differential thermal distribution. Nile tilapia were screened following two different protocols: 1) a suite of individual behavioural tests to screen for personality and 2) thermal choice in a custom-built tank with a thermal gradient (TCH tank) ranging from 21 to 33 °C. A first set of fish were screened for behaviour and then thermal preference, and a second set were tested in the opposite fashion: thermal then behaviour. The final thermal distribution of the fish after 48 h was assessed reflecting final thermal preferendum. Additionally, fish were then challenged using a bacterial Streptococcus iniae model infection to assess the behavioural fever response of proactive and reactive fish. Results showed that individuals with preference for higher temperatures were also classified as proactive with behavioural tests and reactive contemporaries chose significantly lower water temperatures. All groups exhibited behavioural fever recovering personality-specific thermal preferences after 5 days. Our results show that thermal preference can be used as a proxy to assess personality traits in Nile tilapia and it is a central factor to understand the adaptive meaning of animal personality within a population. Importantly, response to infection by expressing behavioural fever overrides personality-related thermal choice. PMID:27219014

  12. Local impact of temperature and precipitation on West Nile virus infection in Culex species mosquitoes in northeast Illinois, USA

    Directory of Open Access Journals (Sweden)

    Haramis Linn

    2010-03-01

    infection data from numerous sources across several years are important to the strength of the models presented. The other spatial environmental factors that tended to be important, including impervious surfaces and elevation measures, would mediate the effect of rainfall on soils and in urban catch basins. Changes in weather patterns with global climate change make it especially important to improve our ability to predict how inter-related local weather and environmental factors affect vectors and vector-borne disease risk. Local impact of temperature and precipitation on West Nile virus infection in Culex species mosquitoes in northeast Illinois, USA.

  13. Mosquito larval habitat mapping using remote sensing and GIS: Implications of coalbed methane development and West Nile virus

    Energy Technology Data Exchange (ETDEWEB)

    Zou, L.; Miller, S.N.; Schmidtmann, E.T. [University of Wyoming, Laramie, WY (United States). Dept. of Renewable Resources

    2006-09-15

    Potential larval habitats of the mosquito Culex tarsalis (Coquillett), implicated as a primary vector of West Nile virus in Wyoming, were identified using integrated remote sensing and geographic information system (GIS) analyses. The study area is in the Powder River Basin of north central Wyoming, an area that has been undergoing a significant increase in coalbed methane gas extractions since the late 1990s. Large volumes of water are discharged, impounded, and released during the extraction of methane gas, creating aquatic habitats that have the potential to support immature mosquito development. Landsat TM and ETM + data were initially classified into spectrally distinct water and vegetation classes, which were in turn used to identify suitable larval habitat sites. This initial habitat classification was refined using knowledge-based GIS techniques requiring spatial data layers for topography, streams, and soils to reduce the potential for overestimation of habitat. Accuracy assessment was carried out using field data and high-resolution aerial photography commensurate with one of the Landsat images. The classifier can identify likely habitat for ponds larger than 0.8 ha (2 acres) with generally satisfactory results (72.1%) with a lower detection limit of approximate to 0.4 ha (1 acre). Results show a 75% increase in potential larval habitats from 1999 to 2004 in the study area, primarily because of the large increase in small coalbed methane water discharge ponds. These results may facilitate mosquito abatement programs in the Powder River Basin with the potential for application throughout the state and region.

  14. Experimental Infection of Cats and Dogs with West Nile Virus

    OpenAIRE

    Austgen, Laura E.; Bowen, Richard A.; Bunning, Michel L.; Davis, Brent S.; Mitchell, Carl J.; Chang, Gwong-Jen J.

    2004-01-01

    Domestic dogs and cats were infected by mosquito bite and evaluated as hosts for West Nile virus (WNV). Viremia of low magnitude and short duration developed in four dogs but they did not display signs of disease. Four cats became viremic, with peak titers ranging from 103.0 to 104.0 PFU/mL. Three of the cats showed mild, non-neurologic signs of disease. WNV was not isolated from saliva of either dogs or cats during the period of viremia. An additional group of four cats were exposed to WNV o...

  15. Merowe Dam and the inundation of paleochannels of the Nile

    CERN Document Server

    Sparavigna, Amelia Carolina

    2010-01-01

    The course of the Nile in northern Sudan follows a contorted path through bedrocks, creating the Great Bend. Few years ago, the satellite images showed a fertile strip of land with villages, where paleochannels of the river hosted many fields with cultivations and archaeological sites. Now, a huge part of this valley is under the waters of Merowe Dam reservoir. Comparing the images of the region before and after the dam gates were closed, we can see that the reservoir created itself through flooding the paleochannels.

  16. Genetically delivered antibody protects against West Nile virus

    OpenAIRE

    Pereboev, Alexander; Borisevich, Viktoriya; Tsuladze, George; Shakhmatov, Mikhail; Hudman, Deborah; Kazachinskaia, Elena; Razumov, Ivan; Svyatchenko, Viktor; Loktev, Valery; Yamshchikov, Vladimir

    2007-01-01

    Gene-based delivery of recombinant antibody genes is a promising therapeutic strategy offering numerous advantages including sustained antibody levels, better safety profile and lower production cost. Here we describe generation of a recombinant antibody Fc-9E2 comprising a fusion protein between human Fc of IgG1 and a single-chain Fv derived from a hybridoma 9E2 secreting a mAb neutralizing West Nile virus (WNV). Fc-9E2 was shown to retain parental mAb's specificity and WNV-neutralizing capa...

  17. Chronic West Nile virus infection in kea (Nestor notabilis).

    Science.gov (United States)

    Bakonyi, Tamás; Gajdon, Gyula K; Schwing, Raoul; Vogl, Wolfgang; Häbich, Annett-Carolin; Thaller, Denise; Weissenböck, Herbert; Rudolf, Ivo; Hubálek, Zdenek; Nowotny, Norbert

    2016-02-01

    Six kea (Nestor notabilis) in human care, naturally infected with West Nile virus (WNV) lineage 2 in Vienna, Austria, in 2008, developed mild to fatal neurological signs. WNV RNA persisted and the virus evolved in the birds' brains, as demonstrated by (phylo)genetic analyses of the complete viral genomes detected in kea euthanized between 2009 and 2014. WNV antibodies persisted in the birds, too. Chronic WNV infection in the brain might contribute to the circulation of the virus through oral transmission to predatory birds.

  18. Interdisciplinary assessment of sea-level rise and climate change impacts on the lower Nile delta, Egypt.

    Science.gov (United States)

    Sušnik, Janez; Vamvakeridou-Lyroudia, Lydia S; Baumert, Niklas; Kloos, Julia; Renaud, Fabrice G; La Jeunesse, Isabelle; Mabrouk, Badr; Savić, Dragan A; Kapelan, Zoran; Ludwig, Ralf; Fischer, Georg; Roson, Roberto; Zografos, Christos

    2015-01-15

    CLImate-induced changes on WAter and SECurity (CLIWASEC) was a cluster of three complementary EC-FP7 projects assessing climate-change impacts throughout the Mediterranean on: hydrological cycles (CLIMB - CLimate-Induced changes on the hydrology of Mediterranean Basins); water security (WASSERMed - Water Availability and Security in Southern EuRope and the Mediterranean) and human security connected with possible hydro-climatic conflicts (CLICO - CLImate change hydro-COnflicts and human security). The Nile delta case study was common between the projects. CLIWASEC created an integrated forum for modelling and monitoring to understand potential impacts across sectors. This paper summarises key results from an integrated assessment of potential challenges to water-related security issues, focusing on expected sea-level rise impacts by the middle of the century. We use this common focus to illustrate the added value of project clustering. CLIWASEC pursued multidisciplinary research by adopting a single research objective: sea-level rise related water security threats, resulting in a more holistic view of problems and potential solutions. In fragmenting research, policy-makers can fail to understand how multiple issues can materialize from one driver. By combining efforts, an integrated assessment of water security threats in the lower Nile is formulated, offering policy-makers a clearer picture of inter-related issues to society and environment. The main issues identified by each project (land subsidence, saline intrusion - CLIMB; water supply overexploitation, land loss - WASSERMed; employment and housing security - CLICO), are in fact related. Water overexploitation is exacerbating land subsidence and saline intrusion, impacting on employment and placing additional pressure on remaining agricultural land and the underdeveloped housing market. All these have wider implications for regional development. This richer understanding could be critical in making better

  19. Interdisciplinary assessment of sea-level rise and climate change impacts on the lower Nile delta, Egypt.

    Science.gov (United States)

    Sušnik, Janez; Vamvakeridou-Lyroudia, Lydia S; Baumert, Niklas; Kloos, Julia; Renaud, Fabrice G; La Jeunesse, Isabelle; Mabrouk, Badr; Savić, Dragan A; Kapelan, Zoran; Ludwig, Ralf; Fischer, Georg; Roson, Roberto; Zografos, Christos

    2015-01-15

    CLImate-induced changes on WAter and SECurity (CLIWASEC) was a cluster of three complementary EC-FP7 projects assessing climate-change impacts throughout the Mediterranean on: hydrological cycles (CLIMB - CLimate-Induced changes on the hydrology of Mediterranean Basins); water security (WASSERMed - Water Availability and Security in Southern EuRope and the Mediterranean) and human security connected with possible hydro-climatic conflicts (CLICO - CLImate change hydro-COnflicts and human security). The Nile delta case study was common between the projects. CLIWASEC created an integrated forum for modelling and monitoring to understand potential impacts across sectors. This paper summarises key results from an integrated assessment of potential challenges to water-related security issues, focusing on expected sea-level rise impacts by the middle of the century. We use this common focus to illustrate the added value of project clustering. CLIWASEC pursued multidisciplinary research by adopting a single research objective: sea-level rise related water security threats, resulting in a more holistic view of problems and potential solutions. In fragmenting research, policy-makers can fail to understand how multiple issues can materialize from one driver. By combining efforts, an integrated assessment of water security threats in the lower Nile is formulated, offering policy-makers a clearer picture of inter-related issues to society and environment. The main issues identified by each project (land subsidence, saline intrusion - CLIMB; water supply overexploitation, land loss - WASSERMed; employment and housing security - CLICO), are in fact related. Water overexploitation is exacerbating land subsidence and saline intrusion, impacting on employment and placing additional pressure on remaining agricultural land and the underdeveloped housing market. All these have wider implications for regional development. This richer understanding could be critical in making better

  20. Intraspecific variation in gill morphology of juvenile Nile perch, Lates niloticus, in Lake Nabugabo, Uganda

    Science.gov (United States)

    Paterson, Jaclyn A.; Chapman, Lauren J.; Schofield, Pamela J.

    2010-01-01

    Several studies have demonstrated intraspecific variation in fish gill size that relates to variation in dissolved oxygen (DO) availability across habitats. In Lake Nabugabo, East Africa, ecological change over the past 12 years has coincided with a shift in the distribution of introduced Nile perch such that a larger proportion of the population now inhabits waters in or near wetland ecotones where DO is lower than in open waters of the lake. In this study, we compared gill size of juvenile Nile perch between wetland and exposed (open-water) habitats of Lake Nabugabo in 2007, as well as between Nile perch collected in 1996 and 2007. For Nile perch of Lake Nabugabo [<20 cm total length (TL)], there was a significant habitat effect on some gill traits. In general, fish from wetland habitats were characterized by a longer total gill filament length and average gill filament length than conspecifics from exposed habitats. Nile perch collected from wetland areas in 2007 had significantly larger gills (total gill filament length) than Nile perch collected in 1996, but there was no difference detected between Nile perch collected from exposed sites in 2007 and conspecifics collected in 1996.

  1. Was Lates Late? A Null Model for the Nile Perch Boom in Lake Victoria

    Science.gov (United States)

    Downing, Andrea S.; Galic, Nika; Goudswaard, Kees P. C.; van Nes, Egbert H.; Scheffer, Marten; Witte, Frans; Mooij, Wolf M.

    2013-01-01

    Nile perch (Lates niloticus) suddenly invaded Lake Victoria between 1979 and 1987, 25 years after its introduction in the Ugandan side of the lake. Nile perch then replaced the native fish diversity and irreversibly altered the ecosystem and its role to lakeshore societies: it is now a prised export product that supports millions of livelihoods. The delay in the Nile perch boom led to a hunt for triggers of the sudden boom and generated several hypotheses regarding its growth at low abundances – all hypotheses having important implications for the management of Nile perch stocks. We use logistic growth as a parsimonious null model to predict when the Nile perch invasion should have been expected, given its growth rate, initial stock size and introduction year. We find the first exponential growth phase can explain the timing of the perch boom at the scale of Lake Victoria, suggesting that complex mechanisms are not necessary to explain the Nile perch invasion or its timing. However, the boom started in Kenya before Uganda, indicating perhaps that Allee effects act at smaller scales than that of the whole Lake. The Nile perch invasion of other lakes indicates that habitat differences may also have an effect on invasion success. Our results suggest there is probably no single management strategy applicable to the whole lake that would lead to both efficient and sustainable exploitation of its resources. PMID:24204684

  2. Nile Red Staining for Oil Determination in Microalgal Cells: A New Insight through Statistical Modelling

    Directory of Open Access Journals (Sweden)

    Ronald Halim

    2015-01-01

    Full Text Available In the wake of global warming and rapid fossil fuel depletion, microalgae emerge as promising feedstocks for sustainable biofuel production. Nile red staining acts as a rapid diagnostic tool to measure the amount of biodiesel-convertible lipid that the cells accumulate. There is a need for the development of a more uniform staining procedure. In its first phase, this study examined the dependence of microalgal Nile red fluorescence (Tetraselmis suecica in terms of its most pertinent staining variables. A quadratic surface model that successfully described the Nile red fluorescence intensity as a composite function of its variables was generated (r2=0.86. Cell concentration was shown to have a significant effect on the fluorescence intensity. Up to a certain threshold, fluorescence intensity was shown to increase with Nile red dye concentration. In its second phase, the study reviewed findings from previous Nile red studies to elucidate some of the fundamental mechanism underlying the diffusion of Nile red dye molecules into the microalgal cells and their subsequent interaction with intracellular lipids. Through the review process, we were able to develop a simple framework that provided a set of guidelines for the standardization of the Nile red staining procedure across different microalgal species.

  3. Ecology of blue straggler stars

    CERN Document Server

    Carraro, Giovanni; Beccari, Giacomo

    2015-01-01

    The existence of blue straggler stars, which appear younger, hotter, and more massive than their siblings, is at odds with a simple picture of stellar evolution. Such stars should have exhausted their nuclear fuel and evolved long ago to become cooling white dwarfs. They are found to exist in globular clusters, open clusters, dwarf spheroidal galaxies of the Local Group, OB associations and as field stars. This book summarises the many advances in observational and theoretical work dedicated to blue straggler stars. Carefully edited extended contributions by well-known experts in the field cover all the relevant aspects of blue straggler stars research: Observations of blue straggler stars in their various environments; Binary stars and formation channels; Dynamics of globular clusters; Interpretation of observational data and comparison with models. The book also offers an introductory chapter on stellar evolution written by the editors of the book.

  4. Karner Blue Butterfly Recovery Plan

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This recovery plan has been prepared by the Karner Blue Butterfly Recovery Team under the leadership of Dr. David Andow, University of Minnesota-St. Paul. Dr. John...

  5. China Mobile: Expanding "Blue Ocean"

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Driving force is crucial for realizing high-speed growth. The strong driving force from "Blue Ocean Strategy" is an important advantage for China Mobile to realize harmonious and leap-forward development.

  6. Blue Ocean vs. Five Forces

    OpenAIRE

    Burke, Andrew; Stel, André; Thurik, Roy

    2010-01-01

    textabstractThe article reports on the authors' research in the Netherlands which focused on a profit model in Dutch retail stores and a so-called blue-ocean approach which requires a new market that attracts consumers and increases profits. Topics include the competitive strategy approach to increasing profits. The authors conclude that the blue-ocean strategy or innovation approach is sustainable.

  7. Revisiting the Tectono-Stratigraphic Evolution of the Eastern Mediterranean Offshore Levant and Nile Delta

    Science.gov (United States)

    Al-Balushi, Abdulaziz; Fraser, Alastair; A-L Jackson, Christopher; Bell, Rebecca; Kusznir, Nick

    2015-04-01

    Although the Eastern Mediterranean has become the focus for increased oil and gas exploration following significant discoveries in the pre-Messinian succession offshore Egypt and the Levant Margin, understanding its tectono-stratigraphic evolution is the first and most important step towards building reliable geological models that underpin petroleum play assessment. The Eastern Mediterranean Basin has evolved through a complex and poorly understood tectonic history. Disagreement within the scientific community relates to the age of rifting, the orientation of the crustal stretching direction and the type of crust underlying the Levant Basin and, by proxy, the magnitude of stretching. We present, for the first time, an interpretation of deep (i.e. 12-20 sec TWT) regional 2D seismic lines covering the entire Levant Basin. We have interpreted nine seismic surfaces (from top basement to seabed) from which depth and isopach maps for key surfaces and intervals have been generated. To constrain the rifting age, we have used a reverse subsidence modelling technique and restored the Middle Jurassic and the Late Cretaceous basin geometry along a NW-trending seismic profile from the Levant Basin. The restorations, for a specific rifting age, that meet geological constraints on water depth that are obtained from well data and seismic stratigraphy, are considered as viable solutions. The type of crust that underlies the Levant Margin has been inferred from the magnitude of the lithospheric stretching derived from gravity inversion and crustal thinning. Our interpretation of top basement and the Middle Jurassic depth-structure maps suggests that rifting in the Levant Basin led to the development of two main depocentres; in the northern Levant and the southern Levant, in the vicinity of the Nile Delta. These depocentres are separated by a series of NE-trending, fault- bound structural highs (i.e. Jonah and Leviathan). The orientation of the faults suggests they formed in

  8. Seasonal and geographic variation of southern blue whale subspecies in the Indian Ocean.

    Science.gov (United States)

    Samaran, Flore; Stafford, Kathleen M; Branch, Trevor A; Gedamke, Jason; Royer, Jean-Yves; Dziak, Robert P; Guinet, Christophe

    2013-01-01

    Understanding the seasonal movements and distribution patterns of migratory species over ocean basin scales is vital for appropriate conservation and management measures. However, assessing populations over remote regions is challenging, particularly if they are rare. Blue whales (Balaenoptera musculus spp) are an endangered species found in the Southern and Indian Oceans. Here two recognized subspecies of blue whales and, based on passive acoustic monitoring, four "acoustic populations" occur. Three of these are pygmy blue whale (B.m. brevicauda) populations while the fourth is the Antarctic blue whale (B.m. intermedia). Past whaling catches have dramatically reduced their numbers but recent acoustic recordings show that these oceans are still important habitat for blue whales. Presently little is known about the seasonal movements and degree of overlap of these four populations, particularly in the central Indian Ocean. We examined the geographic and seasonal occurrence of different blue whale acoustic populations using one year of passive acoustic recording from three sites located at different latitudes in the Indian Ocean. The vocalizations of the different blue whale subspecies and acoustic populations were recorded seasonally in different regions. For some call types and locations, there was spatial and temporal overlap, particularly between Antarctic and different pygmy blue whale acoustic populations. Except on the southernmost hydrophone, all three pygmy blue whale acoustic populations were found at different sites or during different seasons, which further suggests that these populations are generally geographically distinct. This unusual blue whale diversity in sub-Antarctic and sub-tropical waters indicates the importance of the area for blue whales in these former whaling grounds. PMID:23967221

  9. Seasonal and geographic variation of southern blue whale subspecies in the Indian Ocean.

    Directory of Open Access Journals (Sweden)

    Flore Samaran

    Full Text Available Understanding the seasonal movements and distribution patterns of migratory species over ocean basin scales is vital for appropriate conservation and management measures. However, assessing populations over remote regions is challenging, particularly if they are rare. Blue whales (Balaenoptera musculus spp are an endangered species found in the Southern and Indian Oceans. Here two recognized subspecies of blue whales and, based on passive acoustic monitoring, four "acoustic populations" occur. Three of these are pygmy blue whale (B.m. brevicauda populations while the fourth is the Antarctic blue whale (B.m. intermedia. Past whaling catches have dramatically reduced their numbers but recent acoustic recordings show that these oceans are still important habitat for blue whales. Presently little is known about the seasonal movements and degree of overlap of these four populations, particularly in the central Indian Ocean. We examined the geographic and seasonal occurrence of different blue whale acoustic populations using one year of passive acoustic recording from three sites located at different latitudes in the Indian Ocean. The vocalizations of the different blue whale subspecies and acoustic populations were recorded seasonally in different regions. For some call types and locations, there was spatial and temporal overlap, particularly between Antarctic and different pygmy blue whale acoustic populations. Except on the southernmost hydrophone, all three pygmy blue whale acoustic populations were found at different sites or during different seasons, which further suggests that these populations are generally geographically distinct. This unusual blue whale diversity in sub-Antarctic and sub-tropical waters indicates the importance of the area for blue whales in these former whaling grounds.

  10. Seasonal and geographic variation of southern blue whale subspecies in the Indian Ocean.

    Science.gov (United States)

    Samaran, Flore; Stafford, Kathleen M; Branch, Trevor A; Gedamke, Jason; Royer, Jean-Yves; Dziak, Robert P; Guinet, Christophe

    2013-01-01

    Understanding the seasonal movements and distribution patterns of migratory species over ocean basin scales is vital for appropriate conservation and management measures. However, assessing populations over remote regions is challenging, particularly if they are rare. Blue whales (Balaenoptera musculus spp) are an endangered species found in the Southern and Indian Oceans. Here two recognized subspecies of blue whales and, based on passive acoustic monitoring, four "acoustic populations" occur. Three of these are pygmy blue whale (B.m. brevicauda) populations while the fourth is the Antarctic blue whale (B.m. intermedia). Past whaling catches have dramatically reduced their numbers but recent acoustic recordings show that these oceans are still important habitat for blue whales. Presently little is known about the seasonal movements and degree of overlap of these four populations, particularly in the central Indian Ocean. We examined the geographic and seasonal occurrence of different blue whale acoustic populations using one year of passive acoustic recording from three sites located at different latitudes in the Indian Ocean. The vocalizations of the different blue whale subspecies and acoustic populations were recorded seasonally in different regions. For some call types and locations, there was spatial and temporal overlap, particularly between Antarctic and different pygmy blue whale acoustic populations. Except on the southernmost hydrophone, all three pygmy blue whale acoustic populations were found at different sites or during different seasons, which further suggests that these populations are generally geographically distinct. This unusual blue whale diversity in sub-Antarctic and sub-tropical waters indicates the importance of the area for blue whales in these former whaling grounds.

  11. Masculinization of Nile tilapia (Oreochromis niloticus) by immersion in androgens

    Science.gov (United States)

    Gale, W.L.; Fitzpatrick, M.S.; Lucero, M.; Contreras-Sanchez, W.M.; Schreck, C. B.

    1999-01-01

    The use of all-male populations increases the efficiency and feasibility of tilapia aquaculture. The objective of this study was to determine the efficacy of a short-term immersion procedure for masculinizing Nile tilapia (Oreochromis niloticus). Two synthetic androgens were evaluated: 17α-methyldihydrotestosterone (MDHT) and 17α-methyltestosterone (MT). Exposure (3 h) on 10 and again on 13 days post-fertilization to MDHT at 500 μg/1 successfully masculinized fry in all experiments, resulting in 100, 94 and 83 ± 2% males in Experiments 1, 2 and 3, respectively. Immersions in MDHT or MT at 100 μg/1 resulted in significantly skewed sex ratios in Experiments 1 and 3 (MT resulted in 73 and 83 ± 3% males; and MDHT resulted in 72 and 91 ± 1% males) but not in Experiment 2. Immersion in MT at 500 μg/1 only caused masculinization in Experiment 3. Although further research and refinement is needed, immersion of Nile tilapia in MDHT may provide a practical alternative to the use of steroid-treated feed. Furthermore, when compared with current techniques for steroid-induced sex inversion of tilapia, short-term immersion reduces the period of time that workers are exposed to anabolic steroids.

  12. Efficiency of aquatic macrophytes to treat Nile tilapia pond effluents

    Directory of Open Access Journals (Sweden)

    Henry-Silva Gustavo Gonzaga

    2006-01-01

    Full Text Available The effluents from fish farming can increase the quantity of suspended solids and promote the enrichment of nitrogen and phosphorus in aquatic ecosystems. In this context, the aim of this work was to evaluate the efficiency of three species of floating aquatic macrophytes (Eichhornia crassipes, Pistia stratiotes and Salvinia molesta to treat effluents from Nile tilapia culture ponds. The effluent originated from a 1,000-m² pond stocked with 2,000 male Nile tilapia Oreochromis niloticus. The treatment systems consisted of 12 experimental tanks, three tanks for each macrophyte species, and three control tanks (without plants. Water samples were collected from the: (i fish pond source water, (ii effluent from fish pond and (iii effluents from the treatment tanks. The following water variables were evaluated: turbidity, total and dissolved nitrogen, ammoniacal-N, nitrate-N, nitrite-N, total phosphorus and dissolved phosphorus. E. crassipes and P. stratiotes were more efficient in total phosphorus removal (82.0% and 83.3%, respectively and total nitrogen removal (46.1% and 43.9%, respectively than the S. molesta (72.1% total phosphorus and 42.7% total nitrogen and the control (50.3% total phosphorus and 22.8% total nitrogen, indicating that the treated effluents may be reused in the aquaculture activity.

  13. 21 CFR 73.50 - Ultramarine blue.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Ultramarine blue. 73.50 Section 73.50 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.50 Ultramarine blue. (a) Identity. The color additive ultramarine blue is a blue pigment obtained...

  14. Experimental infection of Carrion crows (Corvus corone) with two European West Nile virus (WNV) strains.

    Science.gov (United States)

    Dridi, Maha; Vangeluwe, Didier; Lecollinet, Sylvie; van den Berg, Thierry; Lambrecht, Bénédicte

    2013-07-26

    West Nile virus (WNV) has become a wide-spread arbovirus in Europe and the Mediterranean Basin countries. This emerging zoonotic disease disseminated 13 years ago in North America where its impact on animal and public health has been considerable. Although American corvids have been the most reliable avian sentinels for WN surveillance in the United States, there is so far no data available about the susceptibility of their Western European counterparts to WNV. Clinical follow-up and serum, oral swabs and feathers viral RNA load monitoring was herein performed on wild-caught Carrion crows (Corvus corone) experimentally inoculated with two WNV strains, Is98 that was isolated from a stork in Israel where it elicited high rates of avian deaths in 1998, and Fr2000 which was only associated to sporadic equine cases in Camargue, France in 2000. Inoculated crows were sensitive to both WNV infections and, as expected from the available epidemiological data, Is98 induced a higher mortality rate (100% vs. 33%) and a quicker fatal outcome, with higher viral RNA loads detected in the serum, oral swabs and feathers than in the Fr2000 group. Therefore, Carrion crows should also be a target species for WNV surveillance in Western Europe, where reporting for abnormal mortalities could be completed by viral detection in the herein described avian matrices. These experimental findings also emphasize the peculiarity of the European situation where a large spectrum of WNV genetic and pathotypic variants have been so far isolated despite limited WN disease reports in wild birds. PMID:23434187

  15. Recent circulation of West Nile virus and potentially other closely related flaviviruses in Southern France.

    Science.gov (United States)

    Vittecoq, Marion; Lecollinet, Sylvie; Jourdain, Elsa; Thomas, Frédéric; Blanchon, Thomas; Arnal, Audrey; Lowenski, Steeve; Gauthier-Clerc, Michel

    2013-08-01

    In recent years, the number of West Nile virus (WNV) cases reported in horses and humans has increased dramatically throughout the Mediterranean basin. Furthermore, the emergence of Usutu virus (USUV) in Austria in 2001, and its subsequent expansion to Hungary, Spain, Italy, Switzerland, the United Kingdom, and Germany, has given added cause for concern regarding the impact of the spread of flaviviruses on human and animal health in western Europe. Despite frequent detection of WNV and USUV cases in neighboring countries, no case of WNV has been detected in France since 2006 and USUV has never been reported. However, recent investigations focused on detecting the circulation of flaviviruses in France are lacking. We investigated the circulation of WNV and USUV viruses in wild birds in southern France on the basis of a serological survey conducted on a sentinel species, the magpie (Pica pica), in the Camargue area from November, 2009, to December, 2010. We detected WNV-neutralizing antibodies at a high titer (160) in a second-year bird showing recent exposure to WNV, although no WNV case has been detected in humans or in horses since 2004 in the Camargue. In addition, we observed low titers (10 or 20) of USUV-specific antibodies in six magpies, two of which were also seropositive for WNV. Such low titers do not give grounds for concluding that these birds had been exposed to USUV; cross-reactions at low titers may occur between antigenically closely related flaviviruses. But these results urge for further investigations into the circulation of flaviviruses in southern France. They also emphasize the necessity of undertaking epidemiological studies on a long-term basis, rather than over short periods following public health crises, to gain insight into viral dynamics within natural reservoirs. PMID:23930977

  16. Pesticide residues in Nile tilapia (Oreochromis niloticus) and Nile perch (Lates niloticus) from Southern Lake Victoria, Tanzania

    Energy Technology Data Exchange (ETDEWEB)

    Henry, L. [Chemistry Department, University of Dar es Salaam. PO Box 35061, Dar es Salaam (Tanzania); Kishimba, M.A. [Chemistry Department, University of Dar es Salaam. PO Box 35061, Dar es Salaam (Tanzania)]. E-mail: kishimba@chem.udsm.ac.tz

    2006-03-15

    Nile tilapia (Oreochromis niloticus) and Nile perch (Lates niloticus) samples were collected from fish landing stations in nine riparian districts on the Tanzanian side of Lake Victoria and screened for residues of 64 organochlorine, organophosphorus, carbamate, and pyrethroid pesticides. The residue levels in the fish fillet were up to 0.003, 0.03 and 0.2 mg/kg fresh weight (0.7, 3.8 and 42 mg/kg lipid weight) of fenitrothion, DDT and endosulfan, respectively. Mean levels within sites were up to 0.002, 0.02 and 0.1 mg/kg fresh weight (0.5, 0.5 and 16 mg/kg lipid weight), respectively. The detection of higher levels of p,p'-DDT than the degradation products (p,p'-DDD and p,p'-DDE), and higher levels of endosulfan isomers ({alpha} and {beta}) than the sulphate, in fish samples, implied recent exposure of fish to DDT and endosulfan, respectively. Generally, most of the fish samples had residue levels above the average method detection limits (MDLs), but were within the calculated ADI. - Fish from Lake Victoria had relatively low pesticide levels.

  17. "Clothed in triple blues": sorting out the Italian blues.

    Science.gov (United States)

    Bimler, David; Uusküla, Mari

    2014-04-01

    Cross-cultural comparisons of color perception and cognition often feature versions of the "similarity sorting" procedure. By interpreting the assignment of two color samples to different groups as an indication that the dissimilarity between them exceeds some threshold, sorting data can be regarded as low-resolution similarity judgments. Here we analyze sorting data from speakers of Italian, Russian, and English, applying multidimensional scaling to delineate the boundaries between perceptual categories while highlighting differences between the three populations. Stimuli were 55 color swatches, predominantly from the blue region. Results suggest that at least two Italian words for "blue" are basic, a similar situation to Russian, in contrast to English where a single "blue" term is basic.

  18. Reported Neuroinvasive Cases of West Nile Virus by State, 2002-2014

    Data.gov (United States)

    U.S. Environmental Protection Agency — This map shows the average annual incidence of neuroinvasive West Nile virus disease in each state, which is calculated as the average number of new cases per...

  19. Normal haematology and blood biochemistry of wild Nile crocodiles (Crocodylus niloticus in the Okavango Delta, Botswana

    Directory of Open Access Journals (Sweden)

    C.J. Lovely

    2007-06-01

    Full Text Available Wild Nile crocodiles (Crocodylus niloticus of various size classes were captured in the Okavango Delta, Botswana. Blood was collected from the post occipital sinus and used for the determination of a wide range of haematological and biochemical parameters. These values were compared between the sexes and between 3 size classes. The values were also compared with the limited data available from farmed Nile crocodiles, as well as from other wild Nile crocodiles. The Okavango crocodiles were comparatively anaemic, and had comparatively low total protein and blood glucose levels. There was a high prevalence of Hepatozoon pettiti infection, however, there was no significant difference in haematological values between the infected and uninfected crocodiles. The values reported here will be useful in diagnostic investigations in both zoo and farmed Nile crocodiles.

  20. Reported Neuroinvasive Cases of West Nile Virus by State, 2002–2014

    Data.gov (United States)

    U.S. Environmental Protection Agency — This map shows the average annual incidence of neuroinvasive West Nile virus disease in each state, which is calculated as the average number of new cases per...

  1. Selectivity of three aquatic weeds as diet for Nile tilapia (Oreochromis niloticus)

    OpenAIRE

    Agbede, S.A.; Akinyemi, O.; A. E. Falaye; Atsanda, N. N.; Adeyemo, A.O.; Adesina, A. A.

    2001-01-01

    A total of sixty juvenile Oreochromis niloticus (Nile tilapia) were fed three species of aquatic weed, namely Azolla filiculoides (water fern), Elodea sp. and Pistia stratiotes (water lettuce) to determine which of the weeds will be selectively consumed, and preferred of all. A control group of twenty Nile tilapia was fed compounded feed. The selectivity of the weeds was observed based on their utilization as food source, and Azolla filiculoides was found to be highly utilized, followed by El...

  2. The biology, ecology, population parameters and the fishery of the Nile tilapia, Oreochromis niloticus (L)

    OpenAIRE

    Balirwa, J.S.

    1994-01-01

    Oreochromis niloticus (the Nile tilapia) and three other ti1apine species: Oreochromis leucostictus, Tilapia zi11ii and T. rendallii were introduced into Lakes Victoria, Kyoga and Nabugabo in 1950s and 1960s. The source and foci of the stockings are given by Welcomme (1966) but the origin of the stocked species was Lake Albert. The Nile tilapia was introduced as a management measure to relieve fishing pressure on the endemic tiapiines and, since it grows to a bigger size, to...

  3. MORPHOLOGICAL AND RADIOLOGICAL STUDIES ON THE SKULL OF THE NILE CROCODILE (CROCODYLUS NILOTICUS)

    OpenAIRE

    Nora A. Shaker; Samah H. El-Bably

    2015-01-01

    Background and Aim: Present study provides with more anatomical information on the structure and form of the bones forming the cranium of the Nile crocodile helps in understanding the interpretation of X ray images and surgical affection of the crocodile heads. Materials and Methods: The present study was conducted on six heads of the Nile crocodile (Crocodylus niloticus). The heads were removed from their bodies and prepared by hot water maceration technique. The bones of the skull were s...

  4. Technique for the collection of clear urine from the Nile crocodile (Crocodylus niloticus)

    OpenAIRE

    Dirk G. Booyse; Fritz W. Huchzermeyer; Soley, John T; Herman B. Groenewald; Lizette C. Bekker; Jan G. Myburgh; Taisen Iguchi; Louis J. Guillette, Jr

    2012-01-01

    Urine samples can be a very useful diagnostic tool for the evaluation of animal health. In this article, a simple technique to collect urine from the Nile crocodile (Crocodylus niloticus) was described, based on a similar unpublished technique developed for the American alligator (Alligator mississippiensis) using a canine urinary catheter. With this technique, it was possible to collect relatively clean urine samples from Nile crocodiles of different sizes using canine urinary catheters or s...

  5. Why Do Proteins Glow Blue?

    CERN Document Server

    Sarkar, Sohini; Hazra, Partha; Mandal, Pankaj

    2014-01-01

    Recent literatures reported blue-green emission from amyloid fibril as exclusive signature of fibril formation. This unusual visible luminescence is regularly used to monitor fibril growth. Blue-green emission has also been observed in crystalline protein and in solution. However, the origin of this emission is not known exactly. Our spectroscopic study of serum proteins reveals that the blue-green emission is a property of protein monomer. Evidences suggest that semiconductor-like band structure of proteins with the optical band-gap in the visible region is possibly the origin of this phenomenon. We show here that the band structure of proteins is primarily the result of electron delocalization through the peptide chain, rather than through the hydrogen bond network in secondary structure.

  6. Species diversity defends against the invasion of Nile tilapia (Oreochromis niloticus

    Directory of Open Access Journals (Sweden)

    Gu Dang E.

    2014-05-01

    Full Text Available Nile tilapia (Oreochromis niloticus is one of the most widely cultured species globally and has successfully colonized much of the world. Despite numerous studies of this exotic species, how differences in native communities mitigate the consequences of Nile tilapia invasion is unknown. Theory predicts that communities that are more diverse should be more resistant to exotic species, an effect that is referred to as “biotic resistance”, but these effects are spatially dependent and organism-specific. Field surveys and laboratory experiments were conducted to test the theory of “biotic resistance” and ascertain the relationship between native species richness and the invasion of Nile tilapia. In the field, we found that as native species richness increased, the biomass of Nile tilapia was significantly reduced. Consistent with results from the field, our manipulative experiment indicated that the growth of Nile tilapia was negatively related to native species richness. Thus, our study supports the theory of “biotic resistance” and suggests that species biodiversity represents an important defense against the invasion of Nile tilapia.

  7. The blue-collar brain.

    Science.gov (United States)

    Van Orden, Guy; Hollis, Geoff; Wallot, Sebastian

    2012-01-01

    Much effort has gone into elucidating control of the body by the brain, less so the role of the body in controlling the brain. This essay develops the idea that the brain does a great deal of work in the service of behavior that is controlled by the body, a blue-collar role compared to the white-collar control exercised by the body. The argument that supports a blue-collar role for the brain is also consistent with recent discoveries clarifying the white-collar role of synergies across the body's tensegrity structure, and the evidence of critical phenomena in brain and behavior. PMID:22719730

  8. Water and Benefit Sharing in Transboundary River Basins

    Science.gov (United States)

    Arjoon, D.; Tilmant, A.; Herrmann, M.

    2015-12-01

    Growing water scarcity underlies the importance of cooperation for the effective management of river basins, particularly in the context of international rivers in which unidirectional externalities can lead to asymmetric relationships between riparian countries. Studies have shown that significant economic benefits can be expected through basin-wide cooperation, however, the equitable partitioning of these benefits over the basin is less well studied and tends to overlook the importance of stakeholder input in the definition of equitability. In this study, an institutional arrangement to maximize welfare and then share the scarcity cost in a river basin is proposed. A river basin authority plays the role of a bulk water market operator, efficiently allocating bulk water to the users and collecting bulk water charges which are then equitably redistributed among water users. This highly regulated market restrains the behaviour of water users to control externalities and to ensure basin-wide coordination, enhanced efficiency, and the equitable redistribution of the scarcity cost. The institutional arrangement is implemented using the Eastern Nile River basin as a case study. The importance of this arrangement is that it can be adopted for application in negotiations to cooperate in trans-boundary river basins. The benefit sharing solution proposed is more likely to be perceived as equitable because water users help define the sharing rule. As a result, the definition of the sharing rule is not in question, as it would be if existing rules, such as bankruptcy rules or cooperative game theory solutions, are applied, with their inherent definitions of fairness. Results of the case study show that the sharing rule is predictable. Water users can expect to receive between 93.5% and 95% of their uncontested benefits (benefits that they expect to receive if water was not rationed), depending on the hydrologic scenario.

  9. Use of Testing for West Nile Virus and Other Arboviruses.

    Science.gov (United States)

    Vanichanan, Jakapat; Salazar, Lucrecia; Wootton, Susan H; Aguilera, Elizabeth; Garcia, Melissa N; Murray, Kristy O; Hasbun, Rodrigo

    2016-09-01

    In the United States, the most commonly diagnosed arboviral disease is West Nile virus (WNV) infection. Diagnosis is made by detecting WNV IgG or viral genomic sequences in serum or cerebrospinal fluid. To determine frequency of this testing in WNV-endemic areas, we examined the proportion of tests ordered for patients with meningitis and encephalitis at 9 hospitals in Houston, Texas, USA. We identified 751 patients (567 adults, 184 children), among whom 390 (52%) experienced illness onset during WNV season (June-October). WNV testing was ordered for 281 (37%) of the 751; results indicated acute infection for 32 (11%). Characteristics associated with WNV testing were acute focal neurologic deficits; older age; magnetic resonance imaging; empirically prescribed antiviral therapy; worse clinical outcomes: and concomitant testing for mycobacterial, fungal, or other viral infections. Testing for WNV is underutilized, and testing of patients with more severe disease raises the possibility of diagnostic bias in epidemiologic studies. PMID:27537988

  10. Use of Testing for West Nile Virus and Other Arboviruses

    Science.gov (United States)

    Vanichanan, Jakapat; Salazar, Lucrecia; Wootton, Susan H.; Aguilera, Elizabeth; Garcia, Melissa N.; Murray, Kristy O.

    2016-01-01

    In the United States, the most commonly diagnosed arboviral disease is West Nile virus (WNV) infection. Diagnosis is made by detecting WNV IgG or viral genomic sequences in serum or cerebrospinal fluid. To determine frequency of this testing in WNV-endemic areas, we examined the proportion of tests ordered for patients with meningitis and encephalitis at 9 hospitals in Houston, Texas, USA. We identified 751 patients (567 adults, 184 children), among whom 390 (52%) experienced illness onset during WNV season (June–October). WNV testing was ordered for 281 (37%) of the 751; results indicated acute infection for 32 (11%). Characteristics associated with WNV testing were acute focal neurologic deficits; older age; magnetic resonance imaging; empirically prescribed antiviral therapy; worse clinical outcomes: and concomitant testing for mycobacterial, fungal, or other viral infections. Testing for WNV is underutilized, and testing of patients with more severe disease raises the possibility of diagnostic bias in epidemiologic studies. PMID:27537988

  11. Avian hosts of West Nile virus in Arizona.

    Science.gov (United States)

    Komar, Nicholas; Panella, Nicholas A; Young, Ginger R; Brault, Aaron C; Levy, Craig E

    2013-09-01

    West Nile virus (WNV) causes sporadic outbreaks of human encephalitis in Phoenix, Arizona. To identify amplifying hosts of WNV in the Phoenix area, we blood-sampled resident birds and measured antibody prevalence following an outbreak in the East Valley of metropolitan Phoenix during summer, 2010. House sparrow (Passer domesticus), house finch (Haemorhous mexicanus), great-tailed grackle (Quiscalus mexicanus), and mourning dove (Zenaida macroura) accounted for most WNV infections among locally resident birds. These species roost communally after early summer breeding. In September 2010, Culex vector-avian host contact was 3-fold greater at communal bird roosts compared with control sites, as determined by densities of resting mosquitoes with previous vertebrate contact (i.e., blood-engorged or gravid mosquitoes). Because of the low competence of mourning doves, these were considered weak amplifiers but potentially effective free-ranging sentinels. Highly competent sparrows, finches, and grackles were predicted to be key amplifying hosts for WNV in suburban Phoenix. PMID:23857022

  12. Megalocytivirus infection in cultured Nile tilapia Oreochromis niloticus.

    Science.gov (United States)

    Subramaniam, Kuttichantran; Gotesman, Michael; Smith, Charlie E; Steckler, Natalie K; Kelley, Karen L; Groff, Joseph M; Waltzek, Thomas B

    2016-05-26

    Megalocytiviruses, such as infectious spleen and kidney necrosis virus (ISKNV), induce lethal systemic diseases in both ornamental and food fish species. In this study, we investigated an epizootic affecting Nile tilapia Oreochromis niloticus cultured in the US Midwest. Diseased fish displayed lethargy, gill pallor, and distension of the coelomic cavity due to ascites. Histopathological examination revealed a severe systemic abundance of intravascular megalocytes that were especially prominent in the gills, kidney, spleen, liver, and intestinal submucosa. Transmission electron microscopic examination revealed abundant intracytoplasmic polygonal virions consistent with iridovirus infection. Comparison of the full-length major capsid protein nucleotide sequences from a recent outbreak with a remarkably similar case that occurred at the same facility many years earlier revealed that both epizootics were caused by ISKNV. A comparison of this case with previous reports suggests that ISKNV may represent a greater threat to tilapia aquaculture than previously realized. PMID:27225209

  13. Potential for New York mosquitoes to transmit West Nile virus.

    Science.gov (United States)

    Turell, M J; O'Guinn, M; Oliver, J

    2000-03-01

    We evaluated the potential for several North American mosquito species to transmit the newly introduced West Nile (WN) virus. Mosquitoes collected in the New York City Metropolitan Area during the recent (1999) WN outbreak were allowed to feed on chickens infected with WN virus isolated from a crow that had died during this outbreak. These mosquitoes were tested approximately 2 weeks later to determine infection, dissemination, and transmission rates. Culex pipiens mosquitoes were highly susceptible to infection, and nearly all individuals with a disseminated infection did transmit WN virus by bite. In contrast, Aedes vexans were only moderately susceptible to oral infection; however, those individuals inoculated with WN virus did transmit virus by bite.

  14. Peste des petits ruminants outbreaks in White Nile State, Sudan.

    Science.gov (United States)

    Ishag, Osama M; Saeed, Intisar K; Ali, Yahia H

    2015-01-01

    Eight outbreaks of peste des petits ruminants in sheep and goats were reported in White Nile State, Sudan, between 2008 and 2009. A mortality rate of 4.2% was reported across the different outbreaks. Clinically the disease was characterised by high fever, ocular and nasal discharge, pneumonia, ulceration of the mucous membranes, diarrhoea and death. The postmortem findings included necrotic lesions in the mouth and gastrointestinal tract, and swollen, oedematous lymph nodes associated with the lungs and intestine. Of the 209 serum samples tested by competitive enzyme-linked immunosorbent assay, 113 (54%) were found positive. Peste des petits ruminants virus was confirmed in tissues, nasal swabs and blood samples by immunocapture enzyme-linked immunosorbent assay, reverse-transcription polymerase chain reaction and isolation of the virus in culture of lamb testicle cells. PMID:26304168

  15. West Nile Virus%西尼罗病毒

    Institute of Scientific and Technical Information of China (English)

    Lyle R. Petersen; Anthony A. Marfin; Duane J. Gubler

    2004-01-01

    西尼罗病毒(West Nile Virus,WNV)1999年首次侵入北美洲,在纽约市地区爆发脑膜脑炎导致7人死亡。在此之前,人们对它还不甚知晓。到2002年,人和兽医监测报告指出,在地理上它已向西扩展到太平洋沿岸。同年,WNV引起了北美史无前例的最大一次虫媒病毒脑炎爆发。

  16. Peste des petits ruminants outbreaks in White Nile State, Sudan

    Directory of Open Access Journals (Sweden)

    Osama M. Ishag

    2015-02-01

    Full Text Available Eight outbreaks of peste des petits ruminants in sheep and goats were reported in White Nile State, Sudan, between 2008 and 2009. A mortality rate of 4.2% was reported across the different outbreaks. Clinically the disease was characterised by high fever, ocular and nasal discharge, pneumonia, ulceration of the mucous membranes, diarrhoea and death. The postmortem findings included necrotic lesions in the mouth and gastrointestinal tract, and swollen, oedematous lymph nodes associated with the lungs and intestine. Of the 209 serum samples tested by competitive enzyme-linked immunosorbent assay, 113 (54% were found positive. Peste des petits ruminants virus was confirmed in tissues, nasal swabs and blood samples by immunocapture enzyme-linked immunosorbent assay, reverse-transcription polymerase chain reaction and isolation of the virus in culture of lamb testicle cells.

  17. Ventilation rates indicate stress-coping styles in Nile tilapia.

    Science.gov (United States)

    Barreto, Rodrigo E; Volpato, Gilson L

    2011-12-01

    Behavioural responses to stress can form distinct profiles in a wide range of animals: proactive and reactive profiles or coping styles. Stress responsiveness can also differentiate between the behavioural profiles. The tendency to regain feed intake following transfer to a novel social-isolation tank (the speed of acclimation) can discriminate between proactive or reactive profiles. Consequently, differential stress responsiveness can be linked to this feeding behaviour trait. This study shows that ventilation rates of Nile tilapia, Oreochromis niloticus (L.), correlate with the rate of feeding resumption, following transfer to a novel social-isolation aquarium. Therefore, ventilation rate (VR) indicates coping styles; consequently, VR is a proxy for the way fish will deal with environmental challenges. PMID:22116283

  18. Experimental Infections of Wild Birds with West Nile Virus

    Directory of Open Access Journals (Sweden)

    Elisa Pérez-Ramírez

    2014-02-01

    Full Text Available Avian models of West Nile virus (WNV disease have become pivotal in the study of infection pathogenesis and transmission, despite the intrinsic constraints that represents this type of experimental research that needs to be conducted in biosecurity level 3 (BSL3 facilities. This review summarizes the main achievements of WNV experimental research carried out in wild birds, highlighting advantages and limitations of this model. Viral and host factors that determine the infection outcome are analyzed in detail, as well as recent discoveries about avian immunity, viral transmission, and persistence achieved through experimental research. Studies of laboratory infections in the natural host will help to understand variations in susceptibility and reservoir competence among bird species, as well as in the epidemiological patterns found in different affected areas.

  19. Overview of West Nile Virus Transmission and Epidemiology.

    Science.gov (United States)

    Troupin, Andrea; Colpitts, Tonya M

    2016-01-01

    West Nile virus (WNV) is a mosquito-borne flavivirus that can cause mild-to-severe disease in humans and horses. WNV was first documented in Uganda in 1937 and passed through the majority of Africa, West Asia, and Europe before arriving in the USA (with infections in New York City in 1999). After the spread of the virus on the US east coast, it traveled westward, northward, and southward through the USA and into Central and South America. WNV can cause fever, rashes, nausea, vomiting, and potentially neuroinvasive disease or death. The virus is sustained through a mosquito-bird-mosquito cycle and there are many species that are competent vectors. Unfortunately, there are no vaccines and the only treatment is supportive care. This chapter highlights the epidemiology and transmission of WNV and provides insight into some of the challenges of controlling WNV disease.

  20. Blood cues induce antipredator behavior in Nile tilapia conspecifics.

    Directory of Open Access Journals (Sweden)

    Rodrigo Egydio Barreto

    Full Text Available In this study, we show that the fish Nile tilapia displays an antipredator response to chemical cues present in the blood of conspecifics. This is the first report of alarm response induced by blood-borne chemical cues in fish. There is a body of evidence showing that chemical cues from epidermal 'club' cells elicit an alarm reaction in fish. However, the chemical cues of these 'club' cells are restricted to certain species of fish. Thus, as a parsimonious explanation, we assume that an alarm response to blood cues is a generalized response among animals because it occurs in mammals, birds and protostomian animals. Moreover, our results suggest that researchers must use caution when studying chemically induced alarm reactions because it is difficult to separate club cell cues from traces of blood.

  1. Ventilation rates indicate stress-coping styles in Nile tilapia

    Indian Academy of Sciences (India)

    Rodrigo E Barreto; Gilson L Volpato

    2011-12-01

    Behavioural responses to stress can form distinct profiles in a wide range of animals: proactive and reactive profiles or coping styles. Stress responsiveness can also differentiate between the behavioural profiles. The tendency to regain feed intake following transfer to a novel social-isolation tank (the speed of acclimation) can discriminate between proactive or reactive profiles. Consequently, differential stress responsiveness can be linked to this feeding behaviour trait. This study shows that ventilation rates of Nile tilapia, Oreochromis niloticus (L.), correlate with the rate of feeding resumption, following transfer to a novel social-isolation aquarium. Therefore, ventilation rate (VR) indicates coping styles; consequently, VR is a proxy for the way fish will deal with environmental challenges.

  2. Frequency of West Nile Virus Infection in Iranian Blood Donors.

    Science.gov (United States)

    Aghaie, Afsaneh; Aaskov, John; Chinikar, Sadegh; Niedrig, Matthias; Banazadeh, Soudabeh; Mohammadpour, Hashem Khorsand

    2016-09-01

    West Nile virus (WNV) can be transmitted by blood transfusions and organ transplants. This study was a retrospective study which was performed in Blood Transfusion Center to evaluate the WNV infection in blood donors in Iran. A total of 540 blood samples were taken from volunteer healthy donors who referred for blood donation to Chabahar Blood Center. The presence of WNV was studied by detecting immunoglobulin G (IgG) WNV by enzyme linked immune sorbent assay (ELISA). Demonstration of elevated WNV IgG confirmed by immunoflouorescence assay (IFA) Euroimmun kit. Out of the 540 samples 17.96 % (97 cases) were seropositive by ELISA and 1.48 % (8 cases) was seropositive by IFA. This means that 8.24 % of ELISA seropositive samples were confirmed by IFA. Special attention should be paid to criteria of donor selection, albeit positive results may be due to a previous infection in these donors. PMID:27429528

  3. Screening reservoir systems by considering the efficient trade-offs-informing infrastructure investment decisions on the Blue Nile

    OpenAIRE

    Geressu, R. T.; J. J. Harou

    2015-01-01

    Multi-reservoir system planners should consider how new dams impact downstream reservoirs and the potential contribution of each component to coordinated management. We propose an optimized multi-criteria screening approach to identify best performing designs, i.e., the selection, size and operating rules of new reservoirs within multi-reservoir systems. Reservoir release operating rules and storage sizes are optimized concurrently for each separate infrastructure design under consideration. ...

  4. Diversification of West Nile virus in a subtropical region

    Directory of Open Access Journals (Sweden)

    Mores Christopher N

    2009-07-01

    Full Text Available Abstract Background West Nile virus (WNV has spread across North, Central, and South America since its introduction in 1999. At the start of this spread, Florida was considered a potentially important area with regards to transmission due to its geographic, climatological, and demographic conditions. Curiously, the anticipated high levels of transmission or disease outbreaks have not been observed. As other studies have predicted that the lack of intense WNV transmission is not due to vector incompetence, we sought to evaluate the role of viral strain diversity in WNV transmission in Florida. Therefore, a phylogentic analysis was carried out on several isolates collected from three distinct locations in Florida. Results Contrasting with a positive control collected in Indian River County, Florida during 2003 that contains the original NY99 genotype with valanine at amino acid 159 of the envelope region, all of the isolates collected in 2005 contain the WN02 genotype composed of a substation with alanine at that position indicating the window of introduction of the WN02 genotype occurred between 2003 and 2005. From the eight isolates collected in Duval, Indian River, and Manatee Counties; there is also a silent nucleotide substitution that differentiates the isolates collected on the Atlantic side of the state compared to the isolate collected on the Gulf side, which groups closer to isolates from other locations near the Gulf. Conclusion As a whole, the Florida isolates contained numerous variable nucleotide and amino acid sites from the reference sequences, as well as each other; indicating greater nucleotide diversity within the Florida 2005 isolates than within other regions. Finally, a series of three amino acid substitutions surrounding a set of histidines located in the envelope coding region that hypothesized to play a role in conformational changes was found in the isolate collected in Indian River County, perhaps changing the

  5. Autonomic nervous dysfunction in hamsters infected with West Nile virus.

    Directory of Open Access Journals (Sweden)

    Hong Wang

    Full Text Available Clinical studies and case reports clearly document that West Nile virus (WNV can cause respiratory and gastrointestinal (GI complications. Other functions controlled by the autonomic nervous system may also be directly affected by WNV, such as bladder and cardiac functions. To investigate how WNV can cause autonomic dysfunctions, we focused on the cardiac and GI dysfunctions of rodents infected with WNV. Infected hamsters had distension of the stomach and intestines at day 9 after viral challenge. GI motility was detected by a dye retention assay; phenol red dye was retained more in the stomachs of infected hamsters as compared to sham-infected hamsters. The amplitudes of electromygraphs (EMGs of intestinal muscles were significantly reduced. Myenteric neurons that innervate the intestines, in addition to neurons in the brain stem, were identified to be infected with WNV. These data suggest that infected neurons controlling autonomic function were the cause of GI dysfunction in WNV-infected hamsters. Using radiotelemetry to record electrocardiograms and to measure heart rate variability (HRV, a well-accepted readout for autonomic function, we determined that HRV and autonomic function were suppressed in WNV-infected hamsters. Cardiac histopathology was observed at day 9 only in the right atrium, which was coincident with WNV staining. A subset of WNV infected cells was identified among cells with hyperpolarization-activated cyclic nucleotide-gated potassium channel 4 (HCN4 as a marker for cells in the sinoatrial (SA and atrioventricular (AV nodes. The unique contribution of this study is the discovery that WNV infection of hamsters can lead to autonomic dysfunction as determined by reduced HRV and reduced EMG amplitudes of the GI tract. These data may model autonomic dysfunction of the human West Nile neurological disease.

  6. The Blue Revolution in Asia

    DEFF Research Database (Denmark)

    Ponte, Stefano; Kelling, Ingrid; Jespersen, Karen Sau;

    2014-01-01

    In this article, we examine the upgrading trajectories of selected aquaculture value chains in four Asian countries and the links between upgrading and three factors of value chain governance: coordination mechanisms; types of drivers; and domestic regulation. We find instances of improving produ...... of upgrading the "blue revolution" in Asia...

  7. Liquid biofuels from blue biomass

    DEFF Research Database (Denmark)

    Kádár, Zsófia; Jensen, Annette Eva; Bangsø Nielsen, Henrik;

    2011-01-01

    Marine (blue) biomasses, such as macroalgaes, represent a huge unexploited amount of biomass. With their various chemical compositions, macroalgaes can be a potential substrate for food, feed, biomaterials, pharmaceuticals, health care products and also for bioenergy. Algae use seawater as a growth...

  8. Nobel Prize for blue LEDs

    Science.gov (United States)

    Kraftmakher, Yaakov

    2015-05-01

    A brief review of lighting technologies is presented. Unavoidable restrictions for incandescent light bulbs caused by the Planck distribution and properties of the human eye are illustrated. The efficiency and luminous efficacy of thermal radiation are calculated for various temperatures; the results clearly show the limitations for thermal radiators. The only way to overcome these limitations is using non-thermal radiators, such as fluorescent lamps and light-emitting diodes (LEDs). Unique advantages of LEDs undoubtedly made a revolution in this field. A crucial element of this progress is the blue LEDs (Nobel Prize 2014). Some experiments with a blue and a green LED are described: (i) the luminescence triggered in a green-yellow phosphor inside a white LED by the blue LED; (ii) radiant spectra and ‘efficiency droop’ in the LEDs; (iii) modulation of the blue LED up to 4 MHz; and (iv) the h/e ratio from the turn-on voltage of the green LED. The experiments are suitable for undergraduate laboratories and usable as classroom demonstrations.

  9. Blue Ocean vs. Five Forces

    NARCIS (Netherlands)

    A.E. Burke (Andrew); A.J. van Stel (André); A.R. Thurik (Roy)

    2010-01-01

    textabstractThe article reports on the authors' research in the Netherlands which focused on a profit model in Dutch retail stores and a so-called blue-ocean approach which requires a new market that attracts consumers and increases profits. Topics include the competitive strategy approach to increa

  10. Flavour production of Stilton blue cheese microflora

    OpenAIRE

    Gkatzionis, Konstantinos

    2010-01-01

    In the blue cheese Stilton the starter mould Penicillium roqueforti grows and sporulates during the ripening period and is considered to be responsible for the unique blue cheese aroma. However, the sporulation of the mould, which results in the formation of blue veins, takes place in a fraction of the Stilton matrix which overall is very heterogeneous. Most blue cheeses develop a secondary microflora of yeasts which may affect their aroma. The aim of this study was to investigate the yeast f...

  11. The Nile hydroclimatology: impact of the Sudd wetland

    OpenAIRE

    Mohamed Ali, Y.A.

    2005-01-01

    Hydroclimatology emerges as a new discipline because of the increasing recognition of the coupled nature of landsurfaceatmopshere processes. Land use change affects the atmospheric moisture conditions, not only locally but also at continental scales. Similarly climate change influences river basin hydrology and water resources. Good understanding of the atmospheric part of the regional water cycle is important for sound (integrated) water resources planning and management at river basin scale...

  12. The natural history of West Nile virus infection presenting with West Nile virus meningoencephalitis in a man with a prolonged illness: a case report

    Directory of Open Access Journals (Sweden)

    Wood James B

    2011-05-01

    Full Text Available Abstract Introduction Estimates indicate that West Nile virus infects approximately one and a half million people in the United States of America. Up to 1% may develop West Nile virus neuroinvasive disease, in which infected patients develop any combination of meningitis, encephalitis, or acute paralysis. Case presentation A 56-year-old African-American man presented to our hospital with headache, restlessness, fever, myalgias, decreased appetite, and progressive confusion. A cerebrospinal fluid examination showed mild leukocytosis and an elevated protein level. Testing for routine infections was negative. Brain T2-weighted magnetic resonance imaging scans showed marked enlargement of caudate nuclei and increased intensity within the basal ganglia and thalami. A West Nile virus titer was positive, and serial brain magnetic resonance imaging scans showed resolving abnormalities that paralleled his neurological examination. Conclusion This report is unusual as it portrays the natural history and long-term consequences of West Nile virus meningoencephalitis diagnosed on the basis of serial brain images.

  13. Levant jet system-effect of post LGM seafloor currents on Nile sediment transport in the eastern Mediterranean

    Science.gov (United States)

    Schattner, U.; Gurevich, M.; Kanari, M.; Lazar, M.

    2015-11-01

    Sedimentary development of a continental margin is directly related to seafloor current dynamics. Yet the linkage between the processes remains vague due to the different time scales they represent. To narrow this gap we focus on the thoroughly studied distribution system of Nile derived sediments across the Levant continental margin (eastern Mediterranean). These sediments dominate the Late Quaternary stratigraphy of the entire margin. Their mobilization has been explained exclusively by longshore transport, while oceanographic evidence from the basin and margin are not incorporated in the known mechanism. New data indicates that longshore mechanism is part of a much larger system. Based on integrated interpretation of multibeam bathymetry, high-resolution single-channel seismic reflection and oceanographic (temperature, salinity and chlorophyll) data we suggest a jet current system mobilizes the Levant Surface Water (LSW), Levant Intermediate Water (LIW) and Atlantic Water (AW) northwards along the margin, between 0 and 400 m water depths. On the seafloor, contourite currents form elongated along-strike morphologies. Below 400 m along-dip gravity flows dominate sediment transport to down the slope, below the Eastern Mediterranean Deep Water (EMDW). Initiation of this mechanism during the Pleistocene-Holocene transition and not at the end of the Last Glacial Maximum (LGM) indicates a gradual recovery of the thermo-haline circulation. Current intensification in the early Holocene may have also increased water stratification. This comprehensive mechanism explains sediment transport along the entire depth range of the continental margin, while integrating seafloor currents, morphology, as well as their relation to sea level rise and stratigraphy of water masses in the Levant basin since the LGM. Given the consistency of seafloor currents throughout the Holocene we propose to address them as the Levant Jet System.

  14. Food habits of blue grouse

    Science.gov (United States)

    Stewart, R.E.

    1944-01-01

    The food habits of Blue Grouse vary from a simple winter diet that is made up predominantly of coniferous needles to a complex diet during the summer months, characterized by great variety of foods including green leaves, fruits and seeds, flowers, animal matter and coniferous needles. The spring and fall, which represent the transition periods between these two, are characterized by feeding habits that are generally intermediate. The diets of the two species of Blue Grouse, Dendrugapus obscurus and Dendragapus juliginosus, are quite similar as far as major types of food are concerned, but they differ considerably in the species that are taken. Such differences reflect differences in the vegetation within the ecologic and geographic ranges occupied by the two species.

  15. Thermoluminescence (TL) of Egyptian Blue

    Energy Technology Data Exchange (ETDEWEB)

    Schvoerer, M.; Delavergne, M.-C.; Chapoulie, R.

    1988-01-01

    Egyptian Blue is a synthesized crystalline pictorial pigment with formula CaCuSi/sub 4/O/sub 10/. It has been used in Egypt and Mesopotamia from the 3rd millenium B.C. A preliminary experiment on a recently synthesized sample showed that this pigment is thermoluminescent after ..beta.. irradiation (/sup 90/Sr). As the signal intensity grows linearly with the administered dose within the temperature range commonly used in TL dating, we have been looking for this phenomenon from archaeological pigments. It was encountered with two samples found in excavation. From its intensity and stability we concluded that Egyptian Blue can be dated using TL. This first and positive result encouraged us to extend the method to other types of mineral pigments synthesized by early man, and to suggest that it may be used for direct dating of ancient murals.

  16. The Physics of the Blues

    Science.gov (United States)

    Gibson, J. Murray

    2009-03-01

    In looking at the commonalities between music and science, one sees that the musician's palette is based on the principles of physics. The pitch of a musical note is determined by the frequency of the sound wave. The scales that musicians use to create and play music can be viewed as a set of rules. What makes music interesting is how musicians develop those rules and create ambiguity with them. I will discuss the evolution of western musical scales in this context. As a particular example, ``Blue'' notes are very harmonic notes that are missing from the equal temperament scale. The techniques of piano blues and jazz represent the melding of African and Western music into something totally new and exciting. Live keyboard demonstrations will be used. Beyond any redeeming entertainment value the talk will emphasize the serious connections between science and art in music. Nevertheless tips will be accepted.

  17. European Surveillance for West Nile Virus in Mosquito Populations

    Directory of Open Access Journals (Sweden)

    Nicholas Johnson

    2013-10-01

    Full Text Available A wide range of arthropod-borne viruses threaten both human and animal health either through their presence in Europe or through risk of introduction. Prominent among these is West Nile virus (WNV, primarily an avian virus, which has caused multiple outbreaks associated with human and equine mortality. Endemic outbreaks of West Nile fever have been reported in Italy, Greece, France, Romania, Hungary, Russia and Spain, with further spread expected. Most outbreaks in Western Europe have been due to infection with WNV Lineage 1. In Eastern Europe WNV Lineage 2 has been responsible for human and bird mortality, particularly in Greece, which has experienced extensive outbreaks over three consecutive years. Italy has experienced co-circulation with both virus lineages. The ability to manage this threat in a cost-effective way is dependent on early detection. Targeted surveillance for pathogens within mosquito populations offers the ability to detect viruses prior to their emergence in livestock, equine species or human populations. In addition, it can establish a baseline of mosquito-borne virus activity and allow monitoring of change to this over time. Early detection offers the opportunity to raise disease awareness, initiate vector control and preventative vaccination, now available for horses, and encourage personal protection against mosquito bites. This would have major benefits through financial savings and reduction in equid morbidity/mortality. However, effective surveillance that predicts virus outbreaks is challenged by a range of factors including limited resources, variation in mosquito capture rates (too few or too many, difficulties in mosquito identification, often reliant on specialist entomologists, and the sensitive, rapid detection of viruses in mosquito pools. Surveillance for WNV and other arboviruses within mosquito populations varies between European countries in the extent and focus of the surveillance. This study reviews the

  18. [Cases of West Nile fever in Novosibirsk region in 2004, and the genotyping of its viral pathogen].

    Science.gov (United States)

    Ternovoĭ, V A; Protopopova, E V; Kononova, Iu V; Ol'khovikova, E A; Spiridonova, E A; Akopov, G D; Shestopalov, A M; Loktev, V B

    2007-01-01

    Three cases of West Nile fever were registered for the first time in Novosibirsk region in 2004. The diagnosis was confirmed by revealing IgG against West Nile virus (three cases) and viral RNA (two cases). Sequence analysis of fragments of E protein gene showed that the virus belonged to Ia genotype. PMID:17338376

  19. The invasion of an introduced predator, Nile perch (Lates niloticus, L.) in Lake Victoria (East Africa): chronology and causes

    NARCIS (Netherlands)

    Goudswaard, P.C.; Witte, F.; Katunzi, E.F.B.

    2008-01-01

    Nile perch, a large predatory fish, was introduced into Lake Victoria in 1954. The upsurge of Nile perch in Lake Victoria was first observed in the Nyanza Gulf, Kenya, in 1979. In Ugandan waters this occurred 2¿3 years later and in the Tanzanian Mwanza Gulf 4¿5 years later. At the beginning of the u

  20. Movements of blue sharks (Prionace glauca across their life history.

    Directory of Open Access Journals (Sweden)

    Frederic Vandeperre

    Full Text Available Spatial structuring and segregation by sex and size is considered to be an intrinsic attribute of shark populations. These spatial patterns remain poorly understood, particularly for oceanic species such as blue shark (Prionace glauca, despite its importance for the management and conservation of this highly migratory species. This study presents the results of a long-term electronic tagging experiment to investigate the migratory patterns of blue shark, to elucidate how these patterns change across its life history and to assess the existence of a nursery area in the central North Atlantic. Blue sharks belonging to different life stages (n = 34 were tracked for periods up to 952 days during which they moved extensively (up to an estimated 28.139 km, occupying large parts of the oceanic basin. Notwithstanding a large individual variability, there were pronounced differences in movements and space use across the species' life history. The study provides strong evidence for the existence of a discrete central North Atlantic nursery, where juveniles can reside for up to at least 2 years. In contrast with previously described nurseries of coastal and semi-pelagic sharks, this oceanic nursery is comparatively vast and open suggesting that shelter from predators is not its main function. Subsequently, male and female blue sharks spatially segregate. Females engage in seasonal latitudinal migrations until approaching maturity, when they undergo an ontogenic habitat shift towards tropical latitudes. In contrast, juvenile males generally expanded their range southward and apparently displayed a higher degree of behavioural polymorphism. These results provide important insights into the spatial ecology of pelagic sharks, with implications for the sustainable management of this heavily exploited shark, especially in the central North Atlantic where the presence of a nursery and the seasonal overlap and alternation of different life stages coincides with a

  1. Movements of blue sharks (Prionace glauca) across their life history.

    Science.gov (United States)

    Vandeperre, Frederic; Aires-da-Silva, Alexandre; Fontes, Jorge; Santos, Marco; Serrão Santos, Ricardo; Afonso, Pedro

    2014-01-01

    Spatial structuring and segregation by sex and size is considered to be an intrinsic attribute of shark populations. These spatial patterns remain poorly understood, particularly for oceanic species such as blue shark (Prionace glauca), despite its importance for the management and conservation of this highly migratory species. This study presents the results of a long-term electronic tagging experiment to investigate the migratory patterns of blue shark, to elucidate how these patterns change across its life history and to assess the existence of a nursery area in the central North Atlantic. Blue sharks belonging to different life stages (n = 34) were tracked for periods up to 952 days during which they moved extensively (up to an estimated 28.139 km), occupying large parts of the oceanic basin. Notwithstanding a large individual variability, there were pronounced differences in movements and space use across the species' life history. The study provides strong evidence for the existence of a discrete central North Atlantic nursery, where juveniles can reside for up to at least 2 years. In contrast with previously described nurseries of coastal and semi-pelagic sharks, this oceanic nursery is comparatively vast and open suggesting that shelter from predators is not its main function. Subsequently, male and female blue sharks spatially segregate. Females engage in seasonal latitudinal migrations until approaching maturity, when they undergo an ontogenic habitat shift towards tropical latitudes. In contrast, juvenile males generally expanded their range southward and apparently displayed a higher degree of behavioural polymorphism. These results provide important insights into the spatial ecology of pelagic sharks, with implications for the sustainable management of this heavily exploited shark, especially in the central North Atlantic where the presence of a nursery and the seasonal overlap and alternation of different life stages coincides with a high fishing

  2. Hydrology and empire: the Nile, water imperialism and the partition of Africa.

    Science.gov (United States)

    Tvedt, Terje

    2011-01-01

    Why did the British march up the Nile in the 1890s? The answers to this crucial question of imperial historiography have direct relevance for narratives and theories about imperialism, in general, and the partition of Africa in the nineteenth century, in particular. They will also influence our understanding of some of the main issues in the modern history of the whole region, including state developments and resource utilisation. This article presents an alternative to dominant interpretations of the partition of Africa and the role of British Nile policies in this context. It differs from mainstream diplomatic history, which dominates this research field, in its emphasis on how geographical factors and the hydrological characteristics of the Nile influenced and framed British thinking and actions in the region. Realising the importance of such factors and the specific character of the regional water system does not imply less attention to traditional diplomatic correspondence or to the role of individual imperial entrepreneurs. The strength of this analytical approach theoretically is that it makes it possible to locate the intentions and acts of historical subjects within specific geographical contexts. Empirically, it opens up a whole new set of source material, embedding the reconstruction of the British Nile discourse in a world of Nile plans, water works and hydrological discourses.

  3. Impact of climate change on water and agriculture: Challenges and possible solutions for the Nile Delta

    Science.gov (United States)

    Mabrouk, Badr; Arafa, Salah; Farahat, Hany; Badr, Marmar; Gampe, David; Ludwig, Ralf

    2013-04-01

    The Nile-Delta is subjected to continuous changes; including shoreline changes either erosion or accretion, subsidence of the delta, as well as sea level rise due to climate change. The impacts of climate change on the Nile Delta have been addressed on local and international level as the Nile Delta coastal zones are vulnerable to sea level rise. The poster presents recent research activities and findings from the CLIMB project in the Nile Delta and costal zones of Egypt. Lots of field data have been collected such as aquifer geometry data, soil properties data, well data and contamination sources. All of these data support a coupled modeling approach of the land surface hydrological model WASIM-ETH and the hydrological model MOD-Flow to simulate and project the future impact translation of climate projections into hydrological impacts. Results confirm intensified threads to water security. Increasing potential evaporation (in response to increasing temperature) in combination with decreasing water levels in the Nile river, reduced precipitation and groundwater recharge and deteriorating groundwater quality, imposes great challenges to ensure the supply of drinking water and irrigation. Current irrigation strategies are highly inefficient and must be replaced by new and adapted systems. Based on the results of the coupled modeling approach, various scenarios can be evaluated. The vision is to develop a road map for climate change and green economy that maximizes wellbeing of the Egyptian citizens, operates with environmental limits, and is capable of adapting to global environmental change.

  4. Crystal Structure of West Nile Virus Envelope Glycoprotein Reveals Viral Surface Epitopes

    Energy Technology Data Exchange (ETDEWEB)

    Kanai,R.; Kar, K.; Anthony, K.; Gould, L.; Ledizet, M.; Fikrig, E.; Marasco, W.; Koski, R.; Modis, Y.

    2006-01-01

    West Nile virus, a member of the Flavivirus genus, causes fever that can progress to life-threatening encephalitis. The major envelope glycoprotein, E, of these viruses mediates viral attachment and entry by membrane fusion. We have determined the crystal structure of a soluble fragment of West Nile virus E. The structure adopts the same overall fold as that of the E proteins from dengue and tick-borne encephalitis viruses. The conformation of domain II is different from that in other prefusion E structures, however, and resembles the conformation of domain II in postfusion E structures. The epitopes of neutralizing West Nile virus-specific antibodies map to a region of domain III that is exposed on the viral surface and has been implicated in receptor binding. In contrast, we show that certain recombinant therapeutic antibodies, which cross-neutralize West Nile and dengue viruses, bind a peptide from domain I that is exposed only during the membrane fusion transition. By revealing the details of the molecular landscape of the West Nile virus surface, our structure will assist the design of antiviral vaccines and therapeutics.

  5. Localized Eruptive Blue Nevi after Herpes Zoster

    Science.gov (United States)

    Colson, Fany; Arrese, Jorge E.; Nikkels, Arjen F.

    2016-01-01

    A 52-year-old White man presented with a dozen small, well-restricted, punctiform, asymptomatic, blue-gray macules on the left shoulder. A few months earlier, he had been treated with oral acyclovir for herpes zoster (HZ) affecting the left C7–C8 dermatomes. All the blue macules appeared over a short period of time and then remained stable. The patient had not experienced any previous trauma or had tattooing in this anatomical region. The clinical diagnosis suggested blue nevi. Dermatoscopy revealed small, well-limited, dark-blue, compact, homogeneous areas evoking dermal blue nevi. An excisional biopsy was performed and the histological examination confirmed a blue nevus. As far as we are aware of, this is the first report of eruptive blue nevi following HZ, and it should be included in the differential diagnosis of zosteriform dermatoses responding to an isotopic pathway. In addition, a brief review concerning eruptive nevi is presented. PMID:27462219

  6. Inflation and alternatives with blue tensor spectra

    International Nuclear Information System (INIS)

    We study the tilt of the primordial gravitational waves spectrum. A hint of blue tilt is shown from analyzing the BICEP2 and POLARBEAR data. Motivated by this, we explore the possibilities of blue tensor spectra from the very early universe cosmology models, including null energy condition violating inflation, inflation with general initial conditions, and string gas cosmology, etc. For the simplest G-inflation, blue tensor spectrum also implies blue scalar spectrum. In general, the inflation models with blue tensor spectra indicate large non-Gaussianities. On the other hand, string gas cosmology predicts blue tensor spectrum with highly Gaussian fluctuations. If further experiments do confirm the blue tensor spectrum, non-Gaussianity becomes a distinguishing test between inflation and alternatives

  7. Evaluation of FT-IR and Nile Red methods for microalgal lipid characterization and biomass composition determination.

    Science.gov (United States)

    Feng, Guo-Dong; Zhang, Fang; Cheng, Li-Hua; Xu, Xin-Hua; Zhang, Lin; Chen, Huan-Lin

    2013-01-01

    To characterize lipid content of microalgal cells rapidly and accurately, the gravimetric determination, FT-IR and Nile Red (NR) staining were investigated on six typical eukaryotic and prokaryotic algae species. FT-IR and Nile Red were relative quantification methods and a standard curve was required in contrast to the gravimetric method. The FT-IR method determined the lipid, carbohydrate and protein contents simultaneously assuming that the algal cells only consisted of those three components. The Nile Red method was a relatively rapid method for neutral lipid content characterization by spectrofluorometry and could locate lipid body of the algal cell by fluorescence microscopy. According to sample sources and processing purposes, the gravimetric determination was preferable for large-scale cultivation with low-frequency monitoring, while FT-IR and Nile Red were suitable for general laboratory cultivation with medium-frequency monitoring, in particularly Nile Red was appropriate for small samples when high-frequency screening was required. PMID:23196229

  8. Polish Terms for "Blue" in the Perspective of Vantage Theory

    Science.gov (United States)

    Stanulewicz, Danuta

    2010-01-01

    The Polish set of terms for blue includes, inter alia, the following adjectives: "niebieski" "blue", "blekitny" "(sky) blue", "granatowy" "navy blue", "lazurowy" "azure", "modry" "(intense) blue" and "siny" "(grey) violet-blue". The adjective "niebieski" is the basic term; however, it shares some of its functions with "blekitny", which is…

  9. West Nile virus associations in wild mammals: a synthesis.

    Science.gov (United States)

    Jeffrey Root, J

    2013-04-01

    Exposures to West Nile virus (WNV) have been documented in a variety of wild mammals in both the New and Old Worlds. This review tabulates at least 100 mammal species with evidence of WNV exposure. Many of these exposures were detected in free-ranging mammals, while several were noted in captive individuals. In addition to exposures, this review discusses experimental infections in terms of the potential for reservoir competence of select wild mammal species. Overall, few experimental infections have been conducted on wild mammals. As such, the role of most wild mammals as potential amplifying hosts for WNV is, to date, uncertain. In most instances, experimental infections of wild mammals with WNV have resulted in no or low-level viremia. Some recent studies have indicated that certain species of tree squirrels (Sciurus spp.), eastern chipmunks (Tamias striatus), and eastern cottontail rabbits (Sylvilagus floridanus) develop viremia sufficient for infecting some mosquito species. Certain mammalian species, such as tree squirrels, mesopredators, and deer have been suggested as useful species for WNV surveillance. In this review article, the information pertaining to wild mammal associations with WNV is synthesized. PMID:23212739

  10. Eyewitness introduction to Egypt: "The gift of the Nile".

    Science.gov (United States)

    Brown, Geraldine

    2009-01-01

    Northeastern corner of Africa, lying at the crossroads between the two continents of Europe and Asia (in the Sinai Peninsula), while bordering Libya, Sudan, Israel and the Red Sea. Egypt is the most ancient tourist country in the world. Several health fact-finding missions in the last few years were made to this small country that is frequently defined by the Valley of the Nile. With the spreading deserts on either side, or a very rich heritage of ancient relics, these scenic vistas are without equal elsewhere in the world. Although there are significant cultural differences among the population, Egypt has a long history of ethnic and religious compassion. Among the many rarities, main tourist attractions include the three great Pyramids of Giza and the Sphinx, amazing ancient wonders of the world. These fact-finding missions included how health and medical care are defined, how people and culture are intertwined with its physical features, land use, and the economy and its resources. PMID:19927898

  11. Host sphingomyelin increases West Nile virus infection in vivo.

    Science.gov (United States)

    Martín-Acebes, Miguel A; Gabandé-Rodríguez, Enrique; García-Cabrero, Ana M; Sánchez, Marina P; Ledesma, María Dolores; Sobrino, Francisco; Saiz, Juan-Carlos

    2016-03-01

    Flaviviruses, such as the dengue virus and the West Nile virus (WNV), are arthropod-borne viruses that represent a global health problem. The flavivirus lifecycle is intimately connected to cellular lipids. Among the lipids co-opted by flaviviruses, we have focused on SM, an important component of cellular membranes particularly enriched in the nervous system. After infection with the neurotropic WNV, mice deficient in acid sphingomyelinase (ASM), which accumulate high levels of SM in their tissues, displayed exacerbated infection. In addition, WNV multiplication was enhanced in cells from human patients with Niemann-Pick type A, a disease caused by a deficiency of ASM activity resulting in SM accumulation. Furthermore, the addition of SM to cultured cells also increased WNV infection, whereas treatment with pharmacological inhibitors of SM synthesis reduced WNV infection. Confocal microscopy analyses confirmed the association of SM with viral replication sites within infected cells. Our results unveil that SM metabolism regulates flavivirus infection in vivo and propose SM as a suitable target for antiviral design against WNV. PMID:26764042

  12. Economic conditions predict prevalence of West Nile virus.

    Directory of Open Access Journals (Sweden)

    Ryan J Harrigan

    Full Text Available Understanding the conditions underlying the proliferation of infectious diseases is crucial for mitigating future outbreaks. Since its arrival in North America in 1999, West Nile virus (WNV has led to population-wide declines of bird species, morbidity and mortality of humans, and expenditures of millions of dollars on treatment and control. To understand the environmental conditions that best explain and predict WNV prevalence, we employed recently developed spatial modeling techniques in a recognized WNV hotspot, Orange County, California. Our models explained 85-95% of the variation of WNV prevalence in mosquito vectors, and WNV presence in secondary human hosts. Prevalence in both vectors and humans was best explained by economic variables, specifically per capita income, and by anthropogenic characteristics of the environment, particularly human population and neglected swimming pool density. While previous studies have shown associations between anthropogenic change and pathogen presence, results show that poorer economic conditions may act as a direct surrogate for environmental characteristics related to WNV prevalence. Low-income areas may be associated with higher prevalence for a number of reasons, including variations in property upkeep, microhabitat conditions conducive to viral amplification in both vectors and hosts, host community composition, and human behavioral responses related to differences in education or political participation. Results emphasize the importance and utility of including economic variables in mapping spatial risk assessments of disease.

  13. Potential North American vectors of West Nile virus.

    Science.gov (United States)

    Turell, M J; Sardelis, M R; Dohm, D J; O'Guinn, M L

    2001-12-01

    The outbreak of disease in the New York area in 1999 due to West Nile (WN) virus was the first evidence of the occurrence of this virus in the Americas. To determine potential vectors, more than 15 mosquito species (including Culex pipiens, Cx. nigripalpus, Cx. quinquefasciatus, Cx. salinarius, Aedes albopictus, Ae. vexans, Ochlerotatus japonicus, Oc. sollicitans, Oc. taeniorhynchus, and Oc. triseriatus) from the eastern United States were evaluated for their ability to serve as vectors for the virus isolated from birds collected during the 1999 outbreak in New York. Mosquitoes were allowed to feed on one- to four-day old chickens that had been inoculated with WN virus 1-3 days previously. The mosquitoes were incubated for 12-15 days at 26 degrees C and then allowed to refeed on susceptible chickens and assayed to determine transmission and infection rates. Several container-breeding species (e.g., Ae. albopictus, Oc. atropalpus, and Oc. japonicus) were highly efficient laboratory vectors of WN virus. The Culex species were intermediate in their susceptibility. However, if a disseminated infection developed, all species were able to transmit WN virus by bite. Factors such as population density, feeding preference, longevity, and season of activity also need to be considered in determining the role these species could play in the transmission of WN virus.

  14. Functional Analysis of West Nile Virus Proteins in Human Cells.

    Science.gov (United States)

    Kaufusi, Pakieli H; Tseng, Alanna; Nerurkar, Vivek R

    2016-01-01

    West Nile Virus (WNV) lineage 2 strains have been responsible for large outbreaks of neuroinvasive disease in the United States and Europe between 1999 and 2012. Different strains in this lineage have previously been shown to produce either severe or mild neuroinvasive disease in mice. Phylogenetic and amino acid comparisons between highly or less virulent lineage 2 strains have demonstrated that the nonstructural (NS) gene(s) were most variable. However, the roles of some of the NS proteins in virus life cycle are unknown. The aim of this chapter is to describe simple computational and experimental approaches that can be used to: (1) explore the possible roles of the NS proteins in virus life cycle and (2) test whether the subtle amino acid changes in WNV NS gene products contributed to the evolution of more virulent strains. The computational approaches include methods based on: (1) sequence similarity, (2) sequence motifs, and (3) protein membrane topology predictions. Highlighted experimental procedures include: (1) isolation of viral RNA from WNV-infected cells, (2) cDNA synthesis and PCR amplification of WNV genes, (3) cloning into GFP expression vector, (4) bacterial transformation, (5) plasmid isolation and purification, (6) transfection using activated dendrimers (Polyfect), and (7) immunofluorescence staining of transfected mammalian cells. PMID:27188549

  15. Feeding Nile tilapia with artificial diets and dried bioflocs biomass

    Directory of Open Access Journals (Sweden)

    Nayara Nunes Caldini

    2015-10-01

    Full Text Available The effects of supplying dried bioflocs biomass to Nile tilapia juveniles were investigated in the present work. Fish were stocked in experimental rearing tanks for eight weeks. Selected variables of water quality, growth performance and effluent quality were evaluated. Fish were given different combinations of artificial diets and biofloc biomass, in wet (in natura or dry form. As the supply of artificial diet decreased, the allowance of biofloc biomass increased in the same proportion. Biofloc biomass was produced in two 500-L tanks that received daily applications of dry molasses to adjust the C: N ratio of the water to 15: 1. The concentration of nitrite in water was only reduced in the tanks receiving wet bioflocs. The fish growth performance was poorer in the tanks that received dried biofloc biomass than in the tanks with wet biofloc biomass. Given the lack of positive results, there is no justification to dry the biofloc biomass aiming at delivering it as a dry biomass to reared fish.

  16. MATHEMATICAL ANALYSIS OF WEST NILE VIRUS MODEL WITH DISCRETE DELAYS

    Institute of Scientific and Technical Information of China (English)

    Salisu M. GARBA; Mohammad A. SAFI

    2013-01-01

    The paper presents the basic model for the transmission dynamics of West Nile virus (WNV). The model, which consists of seven mutually-exclusive compartments representing the birds and vector dynamics, has a locally-asymptotically stable disease-free equilibrium whenever the associated reproduction number (R0) is less than unity. As reveal in [3, 20], the analyses of the model show the existence of the phenomenon of backward bifurcation (where the stable disease-free equilibrium of the model co-exists with a stable endemic equilibrium when the reproduction number of the disease is less than unity). It is shown, that the backward bifurcation phenomenon can be removed by substituting the associated standard incidence function with a mass action incidence. Analysis of the reproduction number of the model shows that, the disease will persist, whenever R0 >1, and increase in the length of incubation period can help reduce WNV burden in the community if a certain threshold quantities, denoted by ∆b and ∆v are negative. On the other hand, increasing the length of the incubation period increases disease burden if∆b>0 and ∆v >0. Furthermore, it is shown that adding time delay to the corresponding autonomous model with standard incidence (considered in [2]) does not alter the qualitative dynamics of the autonomous system (with respect to the elimination or persistence of the disease).

  17. Agroindustrial byproducts in diets for Nile tilapia juveniles

    Directory of Open Access Journals (Sweden)

    João Sérgio Oliveira Carvalho

    2012-03-01

    Full Text Available This study was conducted to evaluate performance and body composition of tilapia (Oreochromis niloticus fed diets containing byproducts aerial parts of cassava meal (Manihot esculenta, mesquite pod meal (Prosopis juliflora, cocoa meal (Theobroma cacao and palm kernel cake (Elaeis guineensis and to analyze the economic viability of the feed. A total of 1,350 juvenile males (100 g were distributed in 15 cages (1 m³ in completely randomized design with five treatments (basal diet and four test diets and three replicates. The following aspects were evaluated: final weight, total feed intake, total weight gain, feed conversion, specific growth rate, protein efficiency ratio and survival rate, dry matter, crude protein, fat and ash body, the average cost of feed per kilogram of weight gain and economic efficiency rate. No differences were observed for total consumption of food or survival rate. For other variables, the inclusion of cocoa and cassava meal impaired fish performance. No differences were observed for dry matter, crude protein and body ash. The lower body fat accumulation was recorded for the tilapia fed palm kernel cake. The best economic indicators were found to diets containing palm kernel cake. The byproducts evaluated can be used up to 150 g/kg in feed formulation, providing good performance and economic rate for Nile tilapia.

  18. West Nile virus and USUTU--a threat to Poland.

    Science.gov (United States)

    Moniuszko-Malinowska, Anna; Czupryna, Piotr; Dunaj, Justyna; Zajkowska, Joanna; Siemieniako, Agnieszka; Pancewicz, Sławomir

    2016-01-01

    In recent years emergence of new infectious diseases and the growing spread of pathogens to new areas is observed. Most of these pathogens are zoonotic viruses and their transmission route is from animals to humans and vice versa. These so called emerging and re-emerging pathogens that were present previously only in Africa and Asia are becoming a threat to European countries. These include, e.g. West Nile virus and USUTU virus. The aim of the study is to present the clinical course of infections caused by WVN and USUTU, diagnostic and therapeutic possibilities and, above all, the current epidemiological situation of these infections in the world. We also tried to answer the question whether, there is a risk of infection with these viruses in Poland. After analyzing the available literature we venture a conclusion that in Poland there is a risk of WNV and USUTU infection. Global warming, change of socio-economic conditions, travelling greatly affect the spread of these viruses. In addition there are confirmed human cases of these diseases in countries neighboring Poland, as well as presence of both viruses and the presence of vectors (Culex pipiens sl and Culex torrentium (Diptera: Culicidae)) in our country. All these facts indicate that there is a necessity of epidemiological studies and consideration of these pathogens in the differential diagnosis of febrile illness and neuroinfection. PMID:27344466

  19. West Nile Virus in Resident Birds from Yucatan, Mexico.

    Science.gov (United States)

    Chaves, Andrea; Sotomayor-Bonilla, Jesus; Monge, Otto; Ramírez, Abigaíl; Galindo, Francisco; Sarmiento-Silva, Rosa Elena; Gutiérrez-Espeleta, Gustavo A; Suzán, Gerardo

    2016-01-01

    West Nile virus (WNV) in the Americas is thought to be transported at large spatial scales by migratory birds and locally spread and amplified by resident birds. Local processes, including interspecific interactions and dominance of passerine species recognized as competent reservoirs, may boost infection and maintain endemic cycles. Change in species composition has been recognized as an important driver for infection dynamics. Due to migration and changes in species diversity and composition in wintering grounds, changes in infection prevalence are expected. To these changes, we used PCR to estimate the prevalence of WNV in wild resident birds during the dry and rainy seasons of 2012 in Yucatan, Mexico. Serum samples were obtained from 104 wild birds, belonging to six orders and 35 species. We detected WNV in 14 resident birds, representing 11 species and three orders. Prevalences by order was Passeriformes (27%), Columbiformes (6%), and Piciformes (33%). Resident birds positive to WNV from Yucatan may be indicative of local virus circulation and evidence of past virus transmission activity. PMID:26540336

  20. Differential Virulence and Pathogenesis of West Nile Viruses

    Directory of Open Access Journals (Sweden)

    Emilie Donadieu

    2013-11-01

    Full Text Available West Nile virus (WNV is a neurotropic flavivirus that cycles between mosquitoes and birds but that can also infect humans, horses, and other vertebrate animals. In most humans, WNV infection remains subclinical. However, 20%–40% of those infected may develop WNV disease, with symptoms ranging from fever to meningoencephalitis. A large variety of WNV strains have been described worldwide. Based on their genetic differences, they have been classified into eight lineages; the pathogenic strains belong to lineages 1 and 2. Ten years ago, Beasley et al. (2002 found that dramatic differences exist in the virulence and neuroinvasion properties of lineage 1 and lineage 2 WNV strains. Further insights on how WNV interacts with its hosts have recently been gained; the virus acts either at the periphery or on the central nervous system (CNS, and these observed differences could help explain the differential virulence and neurovirulence of WNV strains. This review aims to summarize the current state of knowledge on factors that trigger WNV dissemination and CNS invasion as well as on the inflammatory response and CNS damage induced by WNV. Moreover, we will discuss how WNV strains differentially interact with the innate immune system and CNS cells, thus influencing WNV pathogenesis.

  1. Host sphingomyelin increases West Nile virus infection in vivo.

    Science.gov (United States)

    Martín-Acebes, Miguel A; Gabandé-Rodríguez, Enrique; García-Cabrero, Ana M; Sánchez, Marina P; Ledesma, María Dolores; Sobrino, Francisco; Saiz, Juan-Carlos

    2016-03-01

    Flaviviruses, such as the dengue virus and the West Nile virus (WNV), are arthropod-borne viruses that represent a global health problem. The flavivirus lifecycle is intimately connected to cellular lipids. Among the lipids co-opted by flaviviruses, we have focused on SM, an important component of cellular membranes particularly enriched in the nervous system. After infection with the neurotropic WNV, mice deficient in acid sphingomyelinase (ASM), which accumulate high levels of SM in their tissues, displayed exacerbated infection. In addition, WNV multiplication was enhanced in cells from human patients with Niemann-Pick type A, a disease caused by a deficiency of ASM activity resulting in SM accumulation. Furthermore, the addition of SM to cultured cells also increased WNV infection, whereas treatment with pharmacological inhibitors of SM synthesis reduced WNV infection. Confocal microscopy analyses confirmed the association of SM with viral replication sites within infected cells. Our results unveil that SM metabolism regulates flavivirus infection in vivo and propose SM as a suitable target for antiviral design against WNV.

  2. Does reservoir host mortality enhance transmission of West Nile virus?

    Directory of Open Access Journals (Sweden)

    Foppa Ivo M

    2007-05-01

    Full Text Available Abstract Background Since its 1999 emergence in New York City, West Nile virus (WNV has become the most important and widespread cause of mosquito-transmitted disease in North America. Its sweeping spread from the Atlantic to the Pacific coast was accompanied by widespread mortality among wild birds, especially corvids. Only sporadic avian mortality had previously been associated with this infection in the Old World. Here, we examine the possibility that reservoir host mortality may intensify transmission, both by concentrating vector mosquitoes on remaining hosts and by preventing the accumulation of "herd immunity". Results Inspection of the Ross-Macdonald expression of the basic reproductive number (R0 suggests that this quantity may increase with reservoir host mortality. Computer simulation confirms this finding and indicates that the level of virulence is positively associated with the numbers of infectious mosquitoes by the end of the epizootic. The presence of reservoir incompetent hosts in even moderate numbers largely eliminated the transmission-enhancing effect of host mortality. Local host die-off may prevent mosquitoes to "waste" infectious blood meals on immune host and may thus facilitate perpetuation and spread of transmission. Conclusion Under certain conditions, host mortality may enhance transmission of WNV and similarly maintained arboviruses and thus facilitate their emergence and spread. The validity of the assumptions upon which this argument is built need to be empirically examined.

  3. West Nile Virus in Resident Birds from Yucatan, Mexico.

    Science.gov (United States)

    Chaves, Andrea; Sotomayor-Bonilla, Jesus; Monge, Otto; Ramírez, Abigaíl; Galindo, Francisco; Sarmiento-Silva, Rosa Elena; Gutiérrez-Espeleta, Gustavo A; Suzán, Gerardo

    2016-01-01

    West Nile virus (WNV) in the Americas is thought to be transported at large spatial scales by migratory birds and locally spread and amplified by resident birds. Local processes, including interspecific interactions and dominance of passerine species recognized as competent reservoirs, may boost infection and maintain endemic cycles. Change in species composition has been recognized as an important driver for infection dynamics. Due to migration and changes in species diversity and composition in wintering grounds, changes in infection prevalence are expected. To these changes, we used PCR to estimate the prevalence of WNV in wild resident birds during the dry and rainy seasons of 2012 in Yucatan, Mexico. Serum samples were obtained from 104 wild birds, belonging to six orders and 35 species. We detected WNV in 14 resident birds, representing 11 species and three orders. Prevalences by order was Passeriformes (27%), Columbiformes (6%), and Piciformes (33%). Resident birds positive to WNV from Yucatan may be indicative of local virus circulation and evidence of past virus transmission activity.

  4. West Nile virus vector Culex modestus established in southern England

    Directory of Open Access Journals (Sweden)

    Golding Nick

    2012-02-01

    Full Text Available Abstract Background The risk posed to the United Kingdom by West Nile virus (WNV has previously been considered low, due to the absence or scarcity of the main Culex sp. bridge vectors. The mosquito Culex modestus is widespread in southern Europe, where it acts as the principle bridge vector of WNV. This species was not previously thought to be present in the United Kingdom. Findings Mosquito larval surveys carried out in 2010 identified substantial populations of Cx. modestus at two sites in marshland in southeast England. Host-seeking-adult traps placed at a third site indicate that the relative seasonal abundance of Cx. modestus peaks in early August. DNA barcoding of these specimens from the United Kingdom and material from southern France confirmed the morphological identification. Conclusions Cx. modestus appears to be established in the North Kent Marshes, possibly as the result of a recent introduction. The addition of this species to the United Kingdom's mosquito fauna may increase the risk posed to the United Kingdom by WNV.

  5. Technique for the collection of clear urine from the Nile crocodile (Crocodylus niloticus

    Directory of Open Access Journals (Sweden)

    Dirk G. Booyse

    2012-07-01

    Full Text Available Urine samples can be a very useful diagnostic tool for the evaluation of animal health. In this article, a simple technique to collect urine from the Nile crocodile (Crocodylus niloticus was described, based on a similar unpublished technique developed for the American alligator (Alligator mississippiensis using a canine urinary catheter. With this technique, it was possible to collect relatively clean urine samples from Nile crocodiles of different sizes using canine urinary catheters or small diameter stomach tubes. Based on the gross anatomical features of the cloaca of the Nile crocodile, it was confirmed that urine accumulates in a chamber consisting of the urodeum and coprodeum. Faecal material is stored temporarily in the very short rectum, which is separated from the urinary chamber by the rectocoprodeal sphincter.

  6. Type Locality for the Great Blue Limestone in the Bingham Nappe, Oquirrh Mountains, Utah

    OpenAIRE

    United States Geological Survey

    2000-01-01

    The Great Blue Limestone was named originally by Spurr (1895) from exposures near the Mercur mining district in the Oquirrh Mountains, Utah. The formation was described in greater detail by Gilluly (1932) in the Ophir mining district. Neither formally established a type locality for this formation in the Oquirrh Mountains. However, the formation has since been correlated broadly with similar sedimentary rocks elsewhere in the adjoining Rocky Mountains and Great Basin regions. For the reco...

  7. Purification and crystallization of dengue and West Nile virus NS2B–NS3 complexes

    International Nuclear Information System (INIS)

    Crystals of dengue serotype 2 and West Nile virus NS2B–NS3 protease complexes have been obtained and the crystals of both diffract to useful resolution. Sample homogeneity was essential for obtaining X-ray-quality crystals of the dengue protease. Controlled proteolysis produced a crystallizable fragment of the apo West Nile virus NS2B–NS3 and crystals were also obtained in the presence of a peptidic inhibitor. Both dengue and West Nile virus infections are an increasing risk to humans, not only in tropical and subtropical areas, but also in North America and parts of Europe. These viral infections are generally transmitted by mosquitoes, but may also be tick-borne. Infection usually results in mild flu-like symptoms, but can also cause encephalitis and fatalities. Approximately 2799 severe West Nile virus cases were reported this year in the United States, resulting in 102 fatalities. With this alarming increase in the number of West Nile virus infections in western countries and the fact that dengue virus already affects millions of people per year in tropical and subtropical climates, there is a real need for effective medicines. A possible therapeutic target to combat these viruses is the protease, which is essential for virus replication. In order to provide structural information to help to guide a lead identification and optimization program, crystallizations of the NS2B–NS3 protease complexes from both dengue and West Nile viruses have been initiated. Crystals that diffract to high resolution, suitable for three-dimensional structure determinations, have been obtained

  8. Purification and crystallization of dengue and West Nile virus NS2B–NS3 complexes

    Energy Technology Data Exchange (ETDEWEB)

    D’Arcy, Allan, E-mail: allan.darcy@novartis.com; Chaillet, Maxime; Schiering, Nikolaus; Villard, Frederic [Novartis Institutes of Biomedical Research, Protease Platform, Klybeckstrasse 144, CH 4002 Basel (Switzerland); Lim, Siew Pheng [Novartis Institutes of Tropical Diseases (Singapore); Lefeuvre, Peggy [Novartis Institutes of Biomedical Research, Protease Platform, Klybeckstrasse 144, CH 4002 Basel (Switzerland); Erbel, Paul [Novartis Institutes of Biomedical Research, Protease Platform, Klybeckstrasse 144, CH 4002 Basel (Switzerland); Novartis Institutes of Tropical Diseases (Singapore)

    2006-02-01

    Crystals of dengue serotype 2 and West Nile virus NS2B–NS3 protease complexes have been obtained and the crystals of both diffract to useful resolution. Sample homogeneity was essential for obtaining X-ray-quality crystals of the dengue protease. Controlled proteolysis produced a crystallizable fragment of the apo West Nile virus NS2B–NS3 and crystals were also obtained in the presence of a peptidic inhibitor. Both dengue and West Nile virus infections are an increasing risk to humans, not only in tropical and subtropical areas, but also in North America and parts of Europe. These viral infections are generally transmitted by mosquitoes, but may also be tick-borne. Infection usually results in mild flu-like symptoms, but can also cause encephalitis and fatalities. Approximately 2799 severe West Nile virus cases were reported this year in the United States, resulting in 102 fatalities. With this alarming increase in the number of West Nile virus infections in western countries and the fact that dengue virus already affects millions of people per year in tropical and subtropical climates, there is a real need for effective medicines. A possible therapeutic target to combat these viruses is the protease, which is essential for virus replication. In order to provide structural information to help to guide a lead identification and optimization program, crystallizations of the NS2B–NS3 protease complexes from both dengue and West Nile viruses have been initiated. Crystals that diffract to high resolution, suitable for three-dimensional structure determinations, have been obtained.

  9. Dynamic water accounting in heavily committed river basins

    Science.gov (United States)

    Tilmant, Amaury; Marques, Guilherme

    2014-05-01

    Many river basins throughout the world are increasingly under pressure as water demands keep rising due to population growth, industrialization, urbanization and rising living standards. In the past, the typical answer to meet those demands focused on the supply-side and involved the construction of hydraulic infrastructures to capture more water from surface water bodies and from aquifers. As river basins were being more and more developed, downstream water users and ecosystems have become increasingly dependant on the management actions taken by upstream users. The increased interconnectedness between water users, aquatic ecosystems and the built environment is further compounded by climate change and its impact on the water cycle. Those pressures mean that it has become increasingly important to measure and account for changes in water fluxes and their corresponding economic value as they progress throughout the river system. Such basin water accounting should provide policy makers with important information regarding the relative contribution of each water user, infrastructure and management decision to the overall economic value of the river basin. This paper presents a dynamic water accounting approach whereby the entire river basin is considered as a value chain with multiple services including production and storage. Water users and reservoirs operators are considered as economic agents who can exchange water with their hydraulic neighbors at a price corresponding to the marginal value of water. Effective water accounting is made possible by keeping track of all water fluxes and their corresponding transactions using the results of a hydro-economic model. The proposed approach is illustrated with the Eastern Nile River basin in Africa.

  10. Bacteria and Turbidity Survey for Blue Mountain Lake, Arkansas, Spring and Summer, 1994

    Science.gov (United States)

    Lasker, A. Dwight

    1995-01-01

    Introduction Blue Mountain Lake darn is located at river mile 74.4 on the Petit Jean River in Logan and Yell Counties in west-central Arkansas (fig. 1). Drainage area above the darn is 488 square miles. Blue Mountain Lake is located between two national forests-the Ozark National Forest and the Ouachita National Forest. The primary purpose for Blue Mountain Lake is flood control, but the lake is used for a variety of recreational purposes. The U.S. Geological Survey (USGS) in cooperation with the U.s. Army Corps of Engineers, Little Rock District, conducted a bacterial and turbidity study of the Blue Mountain Lake Basin during the spring and suri1mer 1994. Samples were collected weekly at 11 locations within the lake basin from May through September 1994. Eight sampling sites were located on tributaries to the lake and three sampling sites were located on the lake with one of the sites located at a swim beach (fig. 2; table 1).

  11. The Role of Innate Immunity in Conditioning Mosquito Susceptibility to West Nile Virus

    Directory of Open Access Journals (Sweden)

    Abhishek N. Prasad

    2013-12-01

    Full Text Available Arthropod-borne viruses (arboviruses represent an emerging threat to human and livestock health globally. In particular, those transmitted by mosquitoes present the greatest challenges to disease control efforts. An understanding of the molecular basis for mosquito innate immunity to arbovirus infection is therefore critical to investigations regarding arbovirus evolution, virus-vector ecology, and mosquito vector competence. In this review, we discuss the current state of understanding regarding mosquito innate immunity to West Nile virus. We draw from the literature with respect to other virus-vector pairings to attempt to draw inferences to gaps in our knowledge about West Nile virus and relevant vectors.

  12. Physicochemical and sensory characteristics of snack made with minced Nile tilapia

    OpenAIRE

    João De Paula Cortez Netto; Paulo Roberto Campagnoli de Oliveira Filho; Judite Lapa-Guimarães; Elisabete Maria Macedo Viegas

    2014-01-01

    Nile tilapia is one of the major fish species cultivated worldwide and in Brazil. The tilapia fillet yield is between 30-35%, thus around 70% of waste is generated. A portion of this waste can be used to obtain minced fish, and the resulting product can be used as meat raw material to prepare fish snacks. The aim of this study was to produce fish snacks containing different inclusion levels (20, 30, and 40%) of minced fish obtained from Nile tilapia processing waste and evaluate their physico...

  13. Diatoms from the Quaternary sediments of the Nile Delta, Egypt, and their palaeoecological significance

    Science.gov (United States)

    Zalat, Abdelfattah A.

    1995-02-01

    This study represents the first contribution describing diatom taxa from the Quaternary sediments of the Nile Delta, Egypt. A total of 99 diatom species and varieties belonging to 28 genera were identified. The palaeoecological conditions during the time of deposition (pH salinity, eutrophication and dissolved silica concentration) are discussed. Deposition of the Quaternary Nile Delta sediments occurred in slightly alkaline, fresh water of oligohalobian type, which was of variable trophic status with a high dissolved silica concentration. The variations visible in the ratio of planktic to epiphytic and benthic diatoms generally reflect shallow environments with water-level changes related to climatic fluctuations.

  14. Water quality and potamoplankton evaluation of the Nile River in Upper Egypt

    OpenAIRE

    Ahmed Mohamed El-Otify; Isaac Agaiby Iskaros

    2015-01-01

    Aim: The composition, abundance, community structure of potamoplankton and major physical and chemical variables of the Nile water in Upper Egypt were investigated to assess its status in different seasons during 2007.MethodsWater samples were collected seasonally during 2007 from six investigated sites from variable depths at levels of 0, 2.5 and 5 m. The area of this investigation is defined as the southern 120 Km of the main stream of the Nile in Upper Egypt (24° 04’ – 25° 00’ latitudes an...

  15. Natural and nosocomial infection in a patient with West Nile encephalitis and extrapyramidal movement disorders.

    Science.gov (United States)

    Solomon, Tom; Fisher, Ann F; Beasley, David W C; Mandava, Pitchaiah; Granwehr, Bruno P; Langsjoen, Hans; Travassos Da Rosa, Amelia P; Barrett, Alan D T; Tesh, Robert B

    2003-06-01

    Since its first recognition in North America in 1999, West Nile virus (WNV) has spread rapidly across the continent, but in many communities, rapid diagnostic tests for detection of WNV infection are not fully available. We describe a patient with extrapyramidal movement disorders and changes in the basal ganglia noted on magnetic resonance images that are characteristic of other flavivirus encephalitides and may help in the recognition of patients with West Nile encephalitis. Detailed molecular analysis suggested that, although our patient received a blood transfusion infected with WNV, the virus that caused his initial infection and encephalitis was probably acquired naturally from a mosquito.

  16. A 7500-year strontium isotope record from the northwestern Nile delta (Maryut lagoon, Egypt)

    Science.gov (United States)

    Flaux, Clément; Claude, Christelle; Marriner, Nick; Morhange, Christophe

    2013-10-01

    During the Holocene, delta evolution has been collectively mediated by relative sea-level changes, continental hydrology and human impacts. In this paper, we present a strontium isotope record from the Maryut lagoon (northwestern Nile delta) to quantify the interplay between relative sea-level variations and Nile flow changes during the past 7500 years. 87Sr/86Sr stratigraphy allows five hydrological stages to be defined. (1) The marine transgression of the area is dated to ˜7.5 ka cal. BP, with a clear marine 87Sr/86Sr signature (0.70905-0.7091). (2) Between ˜7 and ˜5.5 ka, in the context of the so-called African Humid Period (AHP), freshwater inputs became progressively predominant in the Maryut's hydrology. Deceleration of sea-level rise coupled with high Nile discharge induced coastal progradation which led to the progressive closure of the Maryut lagoon. (3) Between ˜5.5 and ˜3.8 ka, the end of the AHP is translated by a progressive hydrological shift from a Nile-dominated to a marine-dominated lagoon (87Sr/86Sr shifts from 0.70865 to 0.7088 to 0.70905-0.70915). (4) From ˜2.8 to ˜1.7 ka, 87Sr/86Sr ratios shift towards lower values (0.7084). Although this change is not precisely resolved because of a hiatus in the Maryut's sedimentary record, the 87Sr/86Sr transition from sea-like to Nile-dominated values is attributed to irrigation practices since the early Ptolemaic period (i.e. since ˜2.3 ka), including the Alexandria canal which played a key role in isolating the Maryut from the Mediterranean sea. (5) The final phase of the record covers the period between ˜1.7 and ˜0.2 ka. 87Sr/86Sr ratios indicate high freshwater inputs (from 0.7080 to 0.7085), except between 1.2 and 1.1 to ˜0.7 ka, when a Maryut lowstand and seawater intrusion are attested. In modern times, the Nile's coastal lagoons have been increasingly supplied by freshwater linked to the diversion of waters from the two Nile branches into the irrigation system. It is suggested that this

  17. Molecularly engineered live-attenuated chimeric West Nile/dengue virus vaccines protect rhesus monkeys from West Nile virus

    International Nuclear Information System (INIS)

    Two molecularly engineered, live-attenuated West Nile virus (WN) vaccine candidates were highly attenuated and protective in rhesus monkeys. The vaccine candidates are chimeric viruses (designated WN/DEN4) bearing the membrane precursor and envelope protein genes of WN on a backbone of dengue 4 virus (DEN4) with or without a deletion of 30 nucleotides (Δ30) in the 3' noncoding region of DEN4. Viremia in WN/DEN4- infected monkeys was reduced 100-fold compared to that in WN- or DEN4-infected monkeys. WN/DEN4-3'Δ30 did not cause detectable viremia, indicating that it is even more attenuated for monkeys. These findings indicate that chimerization itself and the presence of the Δ30 mutation independently contribute to the attenuation phenotype for nonhuman primates. Despite their high level of attenuation in monkeys, the chimeras induced a moderate-to-high titer of neutralizing antibodies and prevented viremia in monkeys challenged with WN. The more attenuated vaccine candidate, WN/DEN4-3'Δ30, will be evaluated first in our initial clinical studies

  18. Various Shades of Blue's Functions

    CERN Document Server

    Janik, R A; Papp, G; Zahed, I; Janik, Romuald A.; Nowak, Maciej A.; Papp, Gabor; Zahed, Ismail

    1997-01-01

    We discuss random matrix models in terms of elementary operations on Blue's functions (functional inverse of Green's functions). We show that such operations embody the essence of a number of physical phenomena whether at/or away from the critical points. We illustrate these assertions by borrowing on a number of recent results in effective QCD in vacuum and matter. We provide simple physical arguments in favor of the universality of the continuum QCD spectral oscillations, whether at zero virtuality, in the bulk of the spectrum or at the chiral critical points. We also discuss effective quantum systems of disorder with strong or weak dissipation (Hatano-Nelson localization).

  19. The water footprint of agricultural products in European river basins

    International Nuclear Information System (INIS)

    This work quantifies the agricultural water footprint (WF) of production (WFprod, agr) and consumption (WFcons, agr) and the resulting net virtual water import (netVWi, agr) of 365 European river basins for a reference period (REF, 1996–2005) and two diet scenarios (a healthy diet based upon food-based dietary guidelines (HEALTHY) and a vegetarian (VEG) diet). In addition to total (tot) amounts, a differentiation is also made between the green (gn), blue (bl) and grey (gy) components. River basins where the REF WFcons, agr, tot exceeds the WFprod, agr, tot (resulting in positive netVWi, agr, tot values), are found along the London–Milan axis. These include the Thames, Scheldt, Meuse, Seine, Rhine and Po basins. River basins where the WFprod, agr, tot exceeds the WFcons, agr, tot are found in Western France, the Iberian Peninsula and the Baltic region. These include the Loire, Ebro and Nemunas basins. Under the HEALTHY diet scenario, the WFcons, agr, tot of most river basins decreases (max −32%), although it was found to increase in some basins in northern and eastern Europe. This results in 22 river basins, including the Danube, shifting from being net VW importers to being net VW exporters. A reduction (max −46%) in WFcons, agr, tot is observed for all but one river basin under the VEG diet scenario. In total, 50 river basins shift from being net VW importers to being net exporters, including the Danube, Seine, Rhone and Elbe basins. Similar observations are made when only the gn + bl and gn components are assessed. When analysing only the bl component, a different river basin pattern is observed. (letters)

  20. The water footprint of agricultural products in European river basins

    Science.gov (United States)

    Vanham, D.; Bidoglio, G.

    2014-05-01

    This work quantifies the agricultural water footprint (WF) of production (WFprod, agr) and consumption (WFcons, agr) and the resulting net virtual water import (netVWi, agr) of 365 European river basins for a reference period (REF, 1996-2005) and two diet scenarios (a healthy diet based upon food-based dietary guidelines (HEALTHY) and a vegetarian (VEG) diet). In addition to total (tot) amounts, a differentiation is also made between the green (gn), blue (bl) and grey (gy) components. River basins where the REF WFcons, agr, tot exceeds the WFprod, agr, tot (resulting in positive netVWi, agr, tot values), are found along the London-Milan axis. These include the Thames, Scheldt, Meuse, Seine, Rhine and Po basins. River basins where the WFprod, agr, tot exceeds the WFcons, agr, tot are found in Western France, the Iberian Peninsula and the Baltic region. These include the Loire, Ebro and Nemunas basins. Under the HEALTHY diet scenario, the WFcons, agr, tot of most river basins decreases (max -32%), although it was found to increase in some basins in northern and eastern Europe. This results in 22 river basins, including the Danube, shifting from being net VW importers to being net VW exporters. A reduction (max -46%) in WFcons, agr, tot is observed for all but one river basin under the VEG diet scenario. In total, 50 river basins shift from being net VW importers to being net exporters, including the Danube, Seine, Rhone and Elbe basins. Similar observations are made when only the gn + bl and gn components are assessed. When analysing only the bl component, a different river basin pattern is observed.

  1. Comprehensive mapping of common immunodominant epitopes in the West Nile virus nonstructural protein 1 recognized by avian antibody responses.

    Directory of Open Access Journals (Sweden)

    Encheng Sun

    Full Text Available West Nile virus (WNV is a mosquito-borne flavivirus that primarily infects birds but occasionally infects humans and horses. Certain species of birds, including crows, house sparrows, geese, blue jays and ravens, are considered highly susceptible hosts to WNV. The nonstructural protein 1 (NS1 of WNV can elicit protective immune responses, including NS1-reactive antibodies, during infection of animals. The antigenicity of NS1 suggests that NS1-reactive antibodies could provide a basis for serological diagnostic reagents. To further define serological reagents for diagnostic use, the antigenic sites in NS1 that are targeted by host immune responses need to be identified and the potential diagnostic value of individual antigenic sites also needs to be defined. The present study describes comprehensive mapping of common immunodominant linear B-cell epitopes in the WNV NS1 using avian WNV NS1 antisera. We screened antisera from chickens, ducks and geese immunized with purified NS1 for reactivity against 35 partially overlapping peptides covering the entire WNV NS1. This study identified twelve, nine and six peptide epitopes recognized by chicken, duck and goose antibody responses, respectively. Three epitopes (NS1-3, 14 and 24 were recognized by antibodies elicited by immunization in all three avian species tested. We also found that NS1-3 and 24 were WNV-specific epitopes, whereas the NS1-14 epitope was conserved among the Japanese encephalitis virus (JEV serocomplex viruses based on the reactivity of avian WNV NS1 antisera against polypeptides derived from the NS1 sequences of viruses of the JEV serocomplex. Further analysis showed that the three common polypeptide epitopes were not recognized by antibodies in Avian Influenza Virus (AIV, Newcastle Disease Virus (NDV, Duck Plague Virus (DPV and Goose Parvovirus (GPV antisera. The knowledge and reagents generated in this study have potential applications in differential diagnostic approaches and

  2. Blue-sheet instability of Schwarzschild wormholes

    International Nuclear Information System (INIS)

    The Schwarzschild wormhole geometry is found to be unstable against the gravitational effects of accumulated, blue-shifted matter and radiation, or ''blue sheets'', accreting along the past horizons. This is shown by constructing a simple model of a wormhole geometry featuring such blue sheets and manifesting their effects. In this model the blue sheets are treated as null delta-function surface layers, and we derive here general conditions for matching spacetime geometries across such null hypersurfaces of discontinuity. These junction conditions are then applied to the construction of the wormhole model. The wormhole evolution depicted in this model shows that the gravitational focussing produced by the blue-sheet mass-energy eventually encloses the blue sheets and past horizons within future horizons, leaving a black-hole geometry. These effects limit emission processes from the region of a wormhole's past singularity into the external universe, and severely restrict the possible role of wormholes in cosmological contexts. (author)

  3. Assessing water footprint at river basin level: a case study for the Heihe River Basin in northwest China

    Directory of Open Access Journals (Sweden)

    Z. Zeng

    2012-05-01

    Full Text Available Increasing water scarcity places considerable importance on the quantification of water footprint (WF at different levels. Despite progress made previously, there are still very few WF studies focusing on specific river basins, especially for those in arid and semi-arid regions. The aim of this study is to quantify WF within the Heihe River Basin (HRB, a basin located in the arid and semi-arid northwest of China. The findings show that the WF was 1768 million m3 yr−1 in the HRB over 2004–2006. Agricultural production was the largest water consumer, accounting for 96% of the WF (92% for crop production and 4% for livestock production. The remaining 4% was for the industrial and domestic sectors. The "blue" component of WF was 811 million m3 yr−1. This indicates a blue water proportion of 46%, which is much higher than the world average and China's average, which is mainly due to the aridness of the HRB and a high dependence on irrigation for crop production. However, even in such a river basin, blue WF was still smaller than green WF, indicating the importance of green water. We find that blue WF exceeded blue water availability during eight months per year and also on an annual basis. This indicates that WF of human activities was achieved at a cost of violating environmental flows of natural freshwater ecosystems, and such a WF pattern is not sustainable. Considering the large WF of crop production, optimizing the crop planting pattern is often a key to achieving more sustainable water use in arid and semi-arid regions.

  4. Assessing water footprint at river basin level: a case study for the Heihe River Basin in northwest China

    Directory of Open Access Journals (Sweden)

    Z. Zeng

    2012-08-01

    Full Text Available Increasing water scarcity places considerable importance on the quantification of water footprint (WF at different levels. Despite progress made previously, there are still very few WF studies focusing on specific river basins, especially for those in arid and semi-arid regions. The aim of this study is to quantify WF within the Heihe River Basin (HRB, a basin located in the arid and semi-arid northwest of China. The findings show that the WF was 1768 million m3 yr−1 in the HRB over 2004–2006. Agricultural production was the largest water consumer, accounting for 96% of the WF (92% for crop production and 4% for livestock production. The remaining 4% was for the industrial and domestic sectors. The "blue" (surface- and groundwater component of WF was 811 million m3 yr−1. This indicates a blue water proportion of 46%, which is much higher than the world average and China's average, which is mainly due to the aridness of the HRB and a high dependence on irrigation for crop production. However, even in such a river basin, blue WF was still smaller than "green" (soil water WF, indicating the importance of green water. We find that blue WF exceeded blue water availability during eight months per year and also on an annual basis. This indicates that WF of human activities was achieved at a cost of violating environmental flows of natural freshwater ecosystems, and such a WF pattern is not sustainable. Considering the large WF of crop production, optimizing the crop planting pattern is often a key to achieving more sustainable water use in arid and semi-arid regions.

  5. Geothermal Technologies Program Blue Ribbon Panel Recommendations

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2011-06-17

    The Geothermal Technologies Program assembled a geothermal Blue Ribbon Panel on March 22-23, 2011 in Albuquerque, New Mexico for a guided discussion on the future of geothermal energy in the United States and the role of the DOE Program. The Geothermal Blue Ribbon Panel Report captures the discussions and recommendations of the experts. An addendum is available here: http://www.eere.energy.gov/geothermal/pdfs/gtp_blue_ribbon_panel_report_addendum10-2011.pdf

  6. African Music: Source of the Blues

    OpenAIRE

    Bayer, Konrad Sidney

    2010-01-01

    [Abstract] African music is the primary source for the blues. Scholars have supplied ample evidence to support this assertion. However, the African retentions still present in the blues are not immediately apparent. African music and the blues share many similarities, including the predominance of rhythm, the uses of music as social commentary and critique, types of instruments, and musical structure. Slaves brought their culture with them to the New World when they were forcibly taken from t...

  7. Propagation of model and forcing uncertainty into hydrological drought characteristics in a multi-model century-long experiment in continental river basins

    Science.gov (United States)

    Samaniego, L. E.; Kumar, R.; Schaefer, D.; Huang, S.; Yang, T.; Mishra, V.; Eisner, S.; Vetter, T.; Pechlivanidis, I.; Liersch, S.; Flörke, M.; Krysanova, V.

    2015-12-01

    Droughts are creeping hydro-meteorological events that bring societiesand natural systems to their limits and inducing considerablesocio-economic losses. Currently it is hypothesized that climate changewill exacerbate current trends leading a more severe and extendeddroughts, as well as, larger than normal recovery periods. Currentassessments, however, lack of a consistent framework to deal withcompatible initial conditions for the impact models and a set ofstandardized historical and future forcings. The ISI-MIP project provides an unique opportunity to understand thepropagation of model and forcing uncertainty into century-long timeseries of drought characteristics using an ensemble of model predictionsacross a broad range of climate scenarios and regions. In the presentstudy, we analyze this issue using the hydrologic simulations carriedout with HYPE, mHM, SWIM, VIC, and WaterGAP3 in seven large continentalriver basins: Amazon, Blue Nile, Ganges, Niger, Mississippi, Rhine,Yellow. All models are calibrated against observed streamflow duringthe period 1971-2001 using the same forcings based on the WATCH datasets. These constrained models were then forced with bias correctedoutputs of five CMIP-5 GCMs under four RCP scenarios (i.e. 2.6, 4.5,6.0, and 8.5 W/m2) for the period 1971-2099. A non-parametric kernel density approach is used to estimate thetemporal evolution of a monthly runoff index based on simulatedstreamflow. Hydrologic simulations corresponding to each GCM during thehistoric period of 1981-2010 serve as reference for the estimation ofthe basin specific monthly probability distribution functions. GCMspecific reference pdfs are then used to recast the future hydrologicmodel outputs from different RCP scenarios. Based on these results,drought severity and duration are investigated during periods: 1)2006-2035, 2) 2036-2065 and 3) 2070-2099. Two main hypothesis areinvestigated: 1) model predictive uncertainty of drought indices amongdifferent hydrologic

  8. Detection and sequencing of West Nile virus RNA from human urine and serum samples during the 2014 seasonal period.

    Science.gov (United States)

    Nagy, Anna; Bán, Enikő; Nagy, Orsolya; Ferenczi, Emőke; Farkas, Ágnes; Bányai, Krisztián; Farkas, Szilvia; Takács, Mária

    2016-07-01

    West Nile virus, a widely distributed mosquito-borne flavivirus, is responsible for numerous animal and human infections in Europe, Africa and the Americas. In Hungary, the average number of human infections falls between 10 and 20 cases each year. The severity of clinically manifesting infections varies widely from the milder form of West Nile fever to West Nile neuroinvasive disease (WNND). In routine laboratory diagnosis of human West Nile virus infections, serological methods are mainly applied due to the limited duration of viremia. However, recent studies suggest that detection of West Nile virus RNA in urine samples may be useful as a molecular diagnostic test for these infections. The Hungarian National Reference Laboratory for Viral Zoonoses serologically confirmed eleven acute human infections during the 2014 seasonal period. In three patients with neurological symptoms, viral RNA was detected from both urine and serum specimens, albeit for a longer period and in higher copy numbers with urine. Phylogenetic analysis of the NS3 genomic region of three strains and the complete genome of one selected strain demonstrated that all three patients had lineage-2 West Nile virus infections. Our findings reaffirm the utility of viral RNA detection in urine as a molecular diagnostic procedure for diagnosis of West Nile virus infections. PMID:27038827

  9. Detection and sequencing of West Nile virus RNA from human urine and serum samples during the 2014 seasonal period.

    Science.gov (United States)

    Nagy, Anna; Bán, Enikő; Nagy, Orsolya; Ferenczi, Emőke; Farkas, Ágnes; Bányai, Krisztián; Farkas, Szilvia; Takács, Mária

    2016-07-01

    West Nile virus, a widely distributed mosquito-borne flavivirus, is responsible for numerous animal and human infections in Europe, Africa and the Americas. In Hungary, the average number of human infections falls between 10 and 20 cases each year. The severity of clinically manifesting infections varies widely from the milder form of West Nile fever to West Nile neuroinvasive disease (WNND). In routine laboratory diagnosis of human West Nile virus infections, serological methods are mainly applied due to the limited duration of viremia. However, recent studies suggest that detection of West Nile virus RNA in urine samples may be useful as a molecular diagnostic test for these infections. The Hungarian National Reference Laboratory for Viral Zoonoses serologically confirmed eleven acute human infections during the 2014 seasonal period. In three patients with neurological symptoms, viral RNA was detected from both urine and serum specimens, albeit for a longer period and in higher copy numbers with urine. Phylogenetic analysis of the NS3 genomic region of three strains and the complete genome of one selected strain demonstrated that all three patients had lineage-2 West Nile virus infections. Our findings reaffirm the utility of viral RNA detection in urine as a molecular diagnostic procedure for diagnosis of West Nile virus infections.

  10. First isolation of West Nile virus from a dromedary camel.

    Science.gov (United States)

    Joseph, Sunitha; Wernery, Ulrich; Teng, Jade Ll; Wernery, Renate; Huang, Yi; Patteril, Nissy Ag; Chan, Kwok-Hung; Elizabeth, Shyna K; Fan, Rachel Yy; Lau, Susanna Kp; Kinne, Jörg; Woo, Patrick Cy

    2016-01-01

    Although antibodies against West Nile virus (WNV) have been detected in the sera of dromedaries in the Middle East, North Africa and Spain, no WNV has been isolated or amplified from dromedary or Bactrian camels. In this study, WNV was isolated from Vero cells inoculated with both nasal swab and pooled trachea/lung samples from a dromedary calf in Dubai. Complete-genome sequencing and phylogenetic analysis using the near-whole-genome polyprotein revealed that the virus belonged to lineage 1a. There was no clustering of the present WNV with other WNVs isolated in other parts of the Middle East. Within lineage 1a, the dromedary WNV occupied a unique position, although it was most closely related to other WNVs of cluster 2. Comparative analysis revealed that the putative E protein encoded by the genome possessed the original WNV E protein glycosylation motif NYS at E154-156, which contained the N-linked glycosylation site at N-154 associated with increased WNV pathogenicity and neuroinvasiveness. In the putative NS1 protein, the A70S substitution observed in other cluster 2 WNVs and P250, which has been implicated in neuroinvasiveness, were present. In addition, the foo motif in the putative NS2A protein, which has been implicated in neuroinvasiveness, was detected. Notably, the amino-acid residues at 14 positions in the present dromedary WNV genome differed from those in most of the closely related WNV strains in cluster 2 of lineage 1a, with the majority of these differences observed in the putative E and NS5 proteins. The present study is the first to demonstrate the isolation of WNV from dromedaries. This finding expands the possible reservoirs of WNV and sources of WNV infection. PMID:27273223

  11. Conservation and variability of West Nile virus proteins.

    Directory of Open Access Journals (Sweden)

    Qi Ying Koo

    Full Text Available West Nile virus (WNV has emerged globally as an increasingly important pathogen for humans and domestic animals. Studies of the evolutionary diversity of the virus over its known history will help to elucidate conserved sites, and characterize their correspondence to other pathogens and their relevance to the immune system. We describe a large-scale analysis of the entire WNV proteome, aimed at identifying and characterizing evolutionarily conserved amino acid sequences. This study, which used 2,746 WNV protein sequences collected from the NCBI GenPept database, focused on analysis of peptides of length 9 amino acids or more, which are immunologically relevant as potential T-cell epitopes. Entropy-based analysis of the diversity of WNV sequences, revealed the presence of numerous evolutionarily stable nonamer positions across the proteome (entropy value of < or = 1. The representation (frequency of nonamers variant to the predominant peptide at these stable positions was, generally, low (< or = 10% of the WNV sequences analyzed. Eighty-eight fragments of length 9-29 amino acids, representing approximately 34% of the WNV polyprotein length, were identified to be identical and evolutionarily stable in all analyzed WNV sequences. Of the 88 completely conserved sequences, 67 are also present in other flaviviruses, and several have been associated with the functional and structural properties of viral proteins. Immunoinformatic analysis revealed that the majority (78/88 of conserved sequences are potentially immunogenic, while 44 contained experimentally confirmed human T-cell epitopes. This study identified a comprehensive catalogue of completely conserved WNV sequences, many of which are shared by other flaviviruses, and majority are potential epitopes. The complete conservation of these immunologically relevant sequences through the entire recorded WNV history suggests they will be valuable as components of peptide-specific vaccines or other

  12. First isolation of West Nile virus from a dromedary camel

    Science.gov (United States)

    Joseph, Sunitha; Wernery, Ulrich; Teng, Jade LL; Wernery, Renate; Huang, Yi; Patteril, Nissy AG; Chan, Kwok-Hung; Elizabeth, Shyna K; Fan, Rachel YY; Lau, Susanna KP; Kinne, Jörg; Woo, Patrick CY

    2016-01-01

    Although antibodies against West Nile virus (WNV) have been detected in the sera of dromedaries in the Middle East, North Africa and Spain, no WNV has been isolated or amplified from dromedary or Bactrian camels. In this study, WNV was isolated from Vero cells inoculated with both nasal swab and pooled trachea/lung samples from a dromedary calf in Dubai. Complete-genome sequencing and phylogenetic analysis using the near-whole-genome polyprotein revealed that the virus belonged to lineage 1a. There was no clustering of the present WNV with other WNVs isolated in other parts of the Middle East. Within lineage 1a, the dromedary WNV occupied a unique position, although it was most closely related to other WNVs of cluster 2. Comparative analysis revealed that the putative E protein encoded by the genome possessed the original WNV E protein glycosylation motif NYS at E154–156, which contained the N-linked glycosylation site at N-154 associated with increased WNV pathogenicity and neuroinvasiveness. In the putative NS1 protein, the A70S substitution observed in other cluster 2 WNVs and P250, which has been implicated in neuroinvasiveness, were present. In addition, the foo motif in the putative NS2A protein, which has been implicated in neuroinvasiveness, was detected. Notably, the amino-acid residues at 14 positions in the present dromedary WNV genome differed from those in most of the closely related WNV strains in cluster 2 of lineage 1a, with the majority of these differences observed in the putative E and NS5 proteins. The present study is the first to demonstrate the isolation of WNV from dromedaries. This finding expands the possible reservoirs of WNV and sources of WNV infection. PMID:27273223

  13. Two Myxobolus spp. infecting the kidney of Nile tilapia (Oreochromis niloticus) in the River Nile at Beni-Suef governorate, Egypt, and the associated renal changes.

    Science.gov (United States)

    Abdel-Baki, Abdel-Azeem S; Abdel-Haleem, Heba M; Sakran, Thabet; Zayed, Eman; Ibrahim, Khalid E; Al-Quraishy, Saleh

    2015-03-01

    Two Myxobolus spp. are described from the kidney of the Nile tilapia (Oreochromis niloticus) collected from the River Nile, Egypt. The prevalence of infection was 61 % (47/77), with the infected fish in each case parasitized by the two Myxobolus species simultaneously. The infection was exhibited as free spores in Bowman capsules and renal glomeruli, which makes their original structures difficult to discern. In some cases, the infection appeared as a fibrous plasmodia-like structure containing degenerated developmental stages and spores in the interstitium. The paper identifies each species based on the morphological characteristics of its spores and identifies the histological impacts of Myxobolus infection in this species of fish. PMID:25566769

  14. Variable blue straggler stars in NGC 5466

    International Nuclear Information System (INIS)

    Nine variable blue stragglers have been found in the globular cluster NGC 5466. The six dwarf Cepheids in this cluster coexist in the instability strip with other nonvariable stars. The three eclipsing binaries are among the hottest of the blue stragglers. The hypothesis is discussed that all blue stragglers in this cluster have undergone mass transfer in close binaries. Under this hypothesis, rotation and spin-down play important roles in controlling the evolution of blue stragglers in old clusters and in affecting some of their observational properties. 14 refs

  15. Evaluating the Use of Commercial West Nile Virus Antigens as Positive Controls in the Rapid Analyte Measurement Platform West Nile Virus Assay.

    Science.gov (United States)

    Burkhalter, Kristen L; Savage, Harry M

    2015-12-01

    We evaluated the utility of 2 types of commercially available antigens as positive controls in the Rapid Analyte Measurement Platform (RAMP®) West Nile virus (WNV) assay. Purified recombinant WNV envelope antigens and whole killed virus antigens produced positive RAMP results and either type would be useful as a positive control. Killed virus antigens provide operational and economic advantages and we recommend their use over purified recombinant antigens. We also offer practical applications for RAMP positive controls and recommendations for preparing them. PMID:26675461

  16. Evaluating the Use of Commercial West Nile Virus Antigens as Positive Controls in the Rapid Analyte Measurement Platform West Nile Virus Assay.

    Science.gov (United States)

    Burkhalter, Kristen L; Savage, Harry M

    2015-12-01

    We evaluated the utility of 2 types of commercially available antigens as positive controls in the Rapid Analyte Measurement Platform (RAMP®) West Nile virus (WNV) assay. Purified recombinant WNV envelope antigens and whole killed virus antigens produced positive RAMP results and either type would be useful as a positive control. Killed virus antigens provide operational and economic advantages and we recommend their use over purified recombinant antigens. We also offer practical applications for RAMP positive controls and recommendations for preparing them.

  17. The geographic concentration of blue carbon in the continental US

    Science.gov (United States)

    Feagin, R. A.; Hinson, A.

    2014-12-01

    Salt water wetlands have the potential to be bought and sold as relatively rich reservoirs of carbon in the context of sequestration projects. However, little is known about the geographic distribution of this potential, and no coarse scale investigation has addressed this ecosystem service at the continental scale. Our objective was to determine blue carbon stocks and flux in coastal wetland soils in the United States and categorize the potential for projects by estuarine basin, state, and wetland type. We linked National Wetlands Inventory (NWI) data with the Soil Survey Geographic Database (SSURGO) through spatial analysis within a Geographic Information System (GIS). We then calculated and mapped soil organic carbon across the continental US. Results were filtered by state, estuarine basin, wetland type, and accumulation rate, and ranking lists for each categorization were produced. The results showed that belowground carbon accumulation is concentrated in specific regions, with the richest and largest reservoirs in the Gulf and Atlantic southeastern estuaries, for example mangrove zones in Florida. Salt marshes on the southern Pacific Coast were relatively low in carbon due to small areas of coverage and the presence of sandy and inorganic soil. The geomorphic position of a wetland within a given estuary, for example on an exposed barrier island versus recessed towards inflowing headwaters, accounted for a greater degree of soil carbon variation than the wetland type, for example woody mangroves versus herbaceous marshes. The potential of a blue carbon sequestration project in relation to its location could be influential in determining wetland policy, conservation, and restoration in the coming decades.

  18. Ecological Risk Assessment of Metal Pollution along Greater Cairo Sector of the River Nile, Egypt, Using Nile Tilapia, Oreochromis niloticus, as Bioindicator

    Directory of Open Access Journals (Sweden)

    Wael A. Omar

    2015-01-01

    Full Text Available The present work aims to evaluate seasonal metal pollution along Greater Cairo sector of the River Nile, Egypt, using wild Nile tilapia, Oreochromis niloticus, as bioindicator and to conduct a risk assessment for human consumers. Greater Cairo is the largest populated area along the whole course of River Nile with a wide range of anthropogenic activities. Effects of metal pollution on fish body indices were studied using condition factor (CF and scaled mass index (SMI. Metal pollution index (MPI showed that the total metal load in fish organs followed the follwoing order: kidney > liver > gill > muscle which gives a better idea about the target organs for metal accumulation. Metal concentrations in fish muscle (edible tissue showed the following arrangement: Fe > Zn > Cu > Mn > Pb > Cd. Metal’s bioaccumulation factor (BAF in fish muscle showed the following arrangement: Zn > Cu > Fe > Mn > Cd and Pb. The hazard index (HI as an indicator of human health risks associated with fish consumption showed that adverse health effects are not expected to occur in most cases. However, the metals’ cumulative risk effects gave an alarming sign specifically at high fish consumption rates.

  19. Possible adaptation measures of agriculture sector in the Nile Delta to climate change impacts

    Directory of Open Access Journals (Sweden)

    S. M. Attaher

    2009-10-01

    Full Text Available The overall agricultural system in the Nile Delta region is considered as one of the highest intensive and complicated agriculture systems in the world. According to the recent studies, the Nile Delta region is one of the highly vulnerable regions in the world to climate change. Sea level rise, soil and water degradation, undiversified crop-pattern, yield reduction, pests and disease severity, and irrigation and drainage management were the main key factors that increased vulnerability of the agriculture sector in that region. The main objective of this study is to conduct a community-based multi-criteria adaptation assessment in the Nile Delta using a preset questionnaire. A list of possible adaptation measures for agriculture sector was evaluated. The results indicated that the Nile Delta growers have strong perceptions to act positively to reduce the impacts of climate change. They reflected the need to improve the their adaptive capacity based on clear scientific message with adequate governmental support to coop with the negative impacts of climate change.

  20. Optimizing fish meal-free commercial diets for Nile Tilapia, Oreochromis niloticus

    Science.gov (United States)

    A feeding trial was conducted in a closed recirculating aquaculture system with Nile tilapia Oreochromis niloticus juveniles (mean weight, 6.81 g) to examine the response to a practical diet containing protein primarily from menhaden fish meal (FM) and soybean meal (SBM) (control, Diet 1) or to diet...

  1. Fishborne trematodes in cultured Nile tilapia (Oreochromis niloticus) and wild-caught fish from Thailand

    DEFF Research Database (Denmark)

    Wiriya, Benjamaporn; Clausen, Jesper Hedegaard; Inpankaew, Tawin;

    2013-01-01

    Fish-borne zoonotic trematode (FZT) infections affect the health of more than 18 million people around the world, particularly in Asian countries. Nile tilapia (Oreochromis niloticus) is a white meat fish that has an increasing national and international market. The objective of this study...

  2. Bacterial distribution and tissue targets following experimental Edwardsiella ictaluri infection in nile tilapia Oreochromis niloticus

    Science.gov (United States)

    Edwardsiella ictaluri, a Gram-negative enteric bacterium, is the known etiological agent of enteric septicemia of catfish. In the last few years, different strains have been implicated as the causative agent of mortality events in cultured fish, including Nile tilapia Oreochromis niloticus L. Due to...

  3. West Nile virus isolated from a Virginia opossum (Didelphis virginiana) in northwestern Missouri, USA, 2012.

    Science.gov (United States)

    Bosco-Lauth, Angela; Harmon, Jessica R; Lash, R Ryan; Weiss, Sonja; Langevin, Stanley; Savage, Harry M; Godsey, Marvin S; Burkhalter, Kristen; Root, J Jeffrey; Gidlewski, Thomas; Nicholson, William L; Brault, Aaron C; Komar, Nicholas

    2014-10-01

    We describe the isolation of West Nile virus (WNV; Flaviviridae, Flavivirus) from blood of a Virginia opossum (Didelphis virginiana) collected in northwestern Missouri, USA in August 2012. Sequencing determined that the virus was related to lineage 1a WNV02 strains. We discuss the role of wildlife in WNV disease epidemiology. PMID:25098303

  4. West Nile Virus RNA in Tissues from Donor Associated with Transmission to Organ Transplant Recipients

    Centers for Disease Control (CDC) Podcasts

    2013-11-19

    William Hale reads an abridged version of the Emerging Infectious Diseases’ dispatch, West Nile Virus RNA in Tissues from Donor Associated with Transmission to Organ Transplant Recipients.  Created: 11/19/2013 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 11/21/2013.

  5. Vector competence of the stable fly (Diptera: Muscidae)for West Nile virus.

    Science.gov (United States)

    Stable flies, which are notorious pests of cattle and other livestock, were suspected of transmitting West Nile virus (WNV) among American white pelicans at the Medicine Lake Wildlife Refuge in northeastern Montana in 2006-2007. However the ability of stable flies to transmit the virus was unknown. ...

  6. Effect of parasitism on vaccine efficacy against Streptococcus iniae in Nile tilapia

    Science.gov (United States)

    Limited information is available on vaccine performance in parasitized fish. The objective of this study was to determine if parasitism of fish affected vaccine efficacy. Antibody level, hematology and survival of Nile tilapia vaccinated with a modified S. iniae bacterin were compared among non-para...

  7. Limitations of microbial hydrocarbon degradation at the Amon mud volcano (Nile deep-sea fan)

    NARCIS (Netherlands)

    Felden, J.; Lichtschlag, A.; Wenzhöfer, F.; de Beer, D.; Feseker, T.; Pop Ristova, P.; de Lange, G.; Boetius, A.

    2013-01-01

    The Amon mud volcano (MV), located at 1250m water depth on the Nile deep-sea fan, is known for its active emission of methane and non-methane hydrocarbons into the hydrosphere. Previous investigations showed a low efficiency of hydrocarbon-degrading anaerobic microbial communities inhabiting the Amo

  8. Genotype by production environment interaction in the GIFT strain of Nile tilapia (Oreochromis niloticus)

    NARCIS (Netherlands)

    Khaw, H.L.; Ponzonia, R.W.; Hamzah, A.; Abu-Bakara, K.R.; Bijma, P.

    2012-01-01

    Three discrete generations of GIFT fish (Nile tilapia strain, Oreochromis niloticus; a total of 10,065 fish with pedigree and phenotypic information) were tested in pond and cage culture environments to determine genotype by production environment interaction between both environments in Malaysia. L

  9. Lake Victoria wetlands and the ecology of the Nile Tilapia, Oreochromis Niloticus Linné

    NARCIS (Netherlands)

    Balirwa, J.S.

    1998-01-01

    The importance of LalNile tilap'a was studied. Five wetland types were defined: papyrus, reed, bulrush, hippo grass, water hyacinth. Hydrology, vegetation and distance towards open water explained the variation in abiotic and biotic factors. Over 30 fish species were ide

  10. Human Monoclonal Antibodies against West Nile Virus Induced by Natural Infection Neutralize at a Postattachment Step

    NARCIS (Netherlands)

    Vogt, Matthew R.; Moesker, Bastiaan; Goudsmit, Jaap; Jongeneelen, Mandy; Austin, S. Kyle; Oliphant, Theodore; Nelson, Steevenson; Pierson, Theodore C.; Wilschut, Jan; Throsby, Mark; Diamond, Michael S.

    2009-01-01

    West Nile virus (WNV) is a neurotropic flavivirus that is now a primary cause of epidemic encephalitis in North America. Studies of mice have demonstrated that the humoral immune response against WNV limits primary infection and protects against a secondary challenge. The most-potent neutralizing mo

  11. Antioxidant and antihypertensive activity of gelatin hydrolysate from Nile tilapia skin

    OpenAIRE

    Choonpicharn, Sadabpong; Jaturasitha, Sanchai; Rakariyatham, Nuansri; Suree, Nuttee; Niamsup, Hataichanoke

    2014-01-01

    Fish skin, a by-product from fish processing industries, still contains a significant amount of protein-rich material. Gelatin was extracted from Nile tilapia skin with the yield 20.77 ± 0.80 % wet weight. Gelatin was then separately hydrolyzed by proteases, including bromelain, papain, trypsin, flavourzyme, alcalase and neutrase. Low molecular weight gelatin hydrolysate (

  12. Genetic parameters for reproductive traits in female Nile tilapia (Oreochromis niloticus): II. Fecundity and fertility

    NARCIS (Netherlands)

    Trong, T.Q.; Arendonk, van J.A.M.; Komen, J.

    2013-01-01

    Harvest weight is the main trait in Nile tilapia (Oreochromis niloticus) breeding programmes. The effects of selection for harvest weight on female reproductive traits are unknown. In this paper we estimate genetic parameters for reproductive traits and their correlation with harvest weight using fe

  13. Spatially Explicit West Nile Virus Risk Modeling in Santa Clara County, CA

    Science.gov (United States)

    A geographic information systems model designed to identify regions of West Nile virus (WNV) transmission risk was tested and calibrated with data collected in Santa Clara County, California. American Crows that died from WNV infection in 2005, provided spatial and temporal ground truth. When the mo...

  14. Susceptibility of Nile tilapia (Oreochromis niloticus) fed dietary sodium chloride to nitrite toxicity

    Science.gov (United States)

    Juvenile Nile tilapia (Oreochromis niloticus) were fed diets supplemented with 0 or 6% NaCl for 10 weeks. Tilapia were exposed to approximately 21 mg/l nitrite-N after five and ten weeks of feeding to determine the effect of dietary NaCl supplementation on resistance to nitrite toxicity. Fish were...

  15. Occurrence of West Nile Virus Antibodies in Wild Birds, Horses, and Humans in Poland

    Directory of Open Access Journals (Sweden)

    Jowita Samanta Niczyporuk

    2015-01-01

    Full Text Available Serum samples of 474 wild birds, 378 horses, and 42 humans with meningitis and lymphocytic meningitis were collected between 2010 and 2014 from different areas of Poland. West Nile virus (WNV antibodies were detected using competition enzyme linked immunosorbent assays: ELISA-1 ID Screen West Nile Competition, IDvet, ELISA-2 ID Screen West Nile IgM Capture, and ELISA-3 Ingezim West Nile Compac. The antibodies were found in 63 (13.29% out of 474 wild bird serum samples and in one (0.26% out of 378 horse serum samples. Fourteen (33.33% out of 42 sera from patients were positive against WNV antigen and one serum was doubtful. Positive samples obtained in birds were next retested with virus microneutralisation test to confirm positive results and cross-reactions with other antigens of the Japanese encephalitis complex. We suspect that positive serological results in humans, birds, and horses indicate that WNV can be somehow closely related with the ecosystem in Poland.

  16. Occurrence of West Nile Virus Antibodies in Wild Birds, Horses, and Humans in Poland

    Science.gov (United States)

    Niczyporuk, Jowita Samanta; Samorek-Salamonowicz, Elżbieta; Lecollinet, Sylvie; Pancewicz, Sławomir Andrzej; Kozdruń, Wojciech; Czekaj, Hanna

    2015-01-01

    Serum samples of 474 wild birds, 378 horses, and 42 humans with meningitis and lymphocytic meningitis were collected between 2010 and 2014 from different areas of Poland. West Nile virus (WNV) antibodies were detected using competition enzyme linked immunosorbent assays: ELISA-1 ID Screen West Nile Competition, IDvet, ELISA-2 ID Screen West Nile IgM Capture, and ELISA-3 Ingezim West Nile Compac. The antibodies were found in 63 (13.29%) out of 474 wild bird serum samples and in one (0.26%) out of 378 horse serum samples. Fourteen (33.33%) out of 42 sera from patients were positive against WNV antigen and one serum was doubtful. Positive samples obtained in birds were next retested with virus microneutralisation test to confirm positive results and cross-reactions with other antigens of the Japanese encephalitis complex. We suspect that positive serological results in humans, birds, and horses indicate that WNV can be somehow closely related with the ecosystem in Poland. PMID:25866767

  17. Fatal clostridial enterotoxemia (Clostrium glycolcum) in an ornate nile monitor (Veranus ornarus)

    DEFF Research Database (Denmark)

    Bertelsen, Mads Frost; Weese, J. Scott

    2006-01-01

    Enterotoxemia caused by Clostridium glycolium was identified as the cause of circulatory collapse and death in a female, 3-year old, captive-bred ornate Nile monitor (Veranus ornatus). Anaerobic culture af fecal samples from 12 other monitor lizards from collection failed to demonstrate the prese...

  18. Apparent digestibility coefficient of duckweed (Lemna minor), fresh and dry for Nile tilapia (Oreochromis niloticus L.)

    NARCIS (Netherlands)

    El-Shafai, S.A.A.M.; El-Gohary, F.; Verreth, J.A.J.; Schrama, J.W.; Gijzen, H.J.

    2004-01-01

    Dry matter (DMD), protein (PD), ash (AD), fat (FD), gross energy (ED) and phosphorus (PhD) digestibility coefficients were determined for five different iso-N fish diets fed to Nile tilapia (Oreochromis niloticus). The control diet contained fishmeal (35%), corn (29%), wheat (20%), wheat bran (10%),

  19. How to us Nile Red, a selective fluorescent stain for microalgal neutral lipids

    NARCIS (Netherlands)

    Alemán-Nava, Gibrán S.; Cuellar-Bermudez, Sara P.; Cuaresma, María; Bosma, Rouke; Muylaert, Koenraad; Ritmann, Bruce E.; Parra, Roberto

    2016-01-01

    The use of Nile Red for rapid monitoring of the neutral lipid content in microalgae has gained interest over the last decade, since neutral lipids are feedstock for renewable transportation fuel. In this review, we discuss the main considerations needed to make an NR protocol reliable for stainin

  20. The Nile valley of Egypt: A major active graben that magnifies seismic waves

    International Nuclear Information System (INIS)

    The Nile valley and the Nile delta are part of the active rift that is probably connected with the Red Sea tectonism. This zone is characterized by small to moderate size earthquakes that have caused extremely severe damage to recent and historical constructions. The most vulnerable area along the Nile valley is the one of Cairo-Faiyoum. Small local and large distant earthquakes could be a source of huge socio-economic damage in this area. The loose soft alluvial sediments of the Nile Canyon are the main factors behind this potential damage because they may greatly amplify the ground motion, as demonstrated by strong ground motion modelling. The largest amplification is generally concentrated along the edges of the graben and occurs at frequencies between 1 Hz and 2 Hz. This may explain the huge damage caused by distant earthquakes during recent and historical times. The distribution of intensity values during the events of 1926 and 1992 is well correlated with the modelled spatial distribution of the spectral amplification. (author)

  1. Significance of Algal Assemblages in Assessing Water Quality of the River Nile at Minia,Egypt

    International Nuclear Information System (INIS)

    A sector of the Nile system in the Providence Minia, has been studied for physicochemical properties of waters and characteristics of the inhabiting algal communities. Monthly samples in the period April, 1994-Marsh, 1995 were collected from three sites on the Nile and one site on a drainage canal connected to it. Samples were analysed for water temperature, ph, inorganic forms of nitrogen, inorganic phosphates, silicates, chemical oxygen demand, total carbohydrates, total proteins, and the major nutritive metal ions; Na+, K+, Ca++and Mg++.Algal samples, collected at the same intervals, were studied for the characteristics of algal communities including diversity of species, abundance of populations and species co,position. A total of 124 taxa were recorded during the period of study of which 27 cyanophytes, 34 chlorophyte, 6 euglenophytes and 57 bacillariophytes. Changes in water chemistry of the river Nile, on receiving discharges from domestic, agricultural and industrial effluents, have been shown to be accompanied with alterations in the algal communities including species composition, species diversity and abundance of populations. Water quality was assessed on the basis of both chemical and biological data and results have indicated that the Nile at the area of study is subjected to eutrophication and organic pollution. Bio indicator species have also used to distinguish polluted and relatively clean localities

  2. Natural mating in Nile tilapia (Oreochromis niloticus L.) : implications for reproductive success, inbreeding and cannibalism

    NARCIS (Netherlands)

    Fessehaye, Y.

    2006-01-01

    Niletilapia ( Oreochromis niloticus L.) is one of the most important species among the commercially farmed tilapias. Both small-scale and commercial production of tilapia is rapidly expanding in many countries of the world because t

  3. Genetic parameters for fillet traits and body measurements in Nile tilapia (Oreochromis niloticus L.)

    NARCIS (Netherlands)

    Rutten, M.J.M.; Bovenhuis, H.; Komen, J.

    2005-01-01

    Fillet weight is an economically important trait in Nile tilapia production for the European market which asks for fish with average body weights of at least 700 g. Genetic parameters to design or optimize breeding programs for these body weights are lacking. In an earlier study we showed that high

  4. Noncoding subgenomic flavivirus RNA: multiple functions in West Nile virus pathogenesis and modulation of host responses

    NARCIS (Netherlands)

    Roby, J.A.; Pijlman, G.P.; Wilusz, J.; Khromykh, A.A.

    2014-01-01

    Flaviviruses are a large group of positive strand RNA viruses transmitted by arthropods that include many human pathogens such as West Nile virus (WNV), Japanese encephalitis virus (JEV), yellow fever virus, dengue virus, and tick-borne encephalitis virus. All members in this genus tested so far are

  5. Detecting West Nile Virus in Owls and Raptors by an Antigen-capture Assay

    OpenAIRE

    Gancz, Ady Y.; Campbell, Douglas G.; Barker, Ian K; Lindsay, Robbin; Hunter, Bruce

    2004-01-01

    We evaluated a rapid antigen-capture assay (VecTest) for detection of West Nile virus in oropharyngeal and cloacal swabs, collected at necropsy from owls (N = 93) and raptors (N = 27). Sensitivity was 93.5%–95.2% for northern owl species but

  6. Aggression and mortality among Nile tilapia (Oreochromis niloticus) maintained in the laboratory at different densities

    Science.gov (United States)

    Because Nile tilapia (Oreochromis niloticus) density may affect stress levels, metabolism, and survival among tilapia in experimental studies and thus may affect experimental results, tilapia were held in a commonly-used commercial tank system to assess the relationship between fish density and beha...

  7. Complete genome sequence of a virulent Streptococcus agalactiae strain 138P isolated from diseased Nile tilapia

    Science.gov (United States)

    Streptococcus agalactiae strain 138P was isolated from the kidney of diseased Nile tilapia in Idaho during a 2007 streptococcal disease outbreak. The full genome of S. agalactiae 138P is 1,838,716 bp. The availability of this genome will allow comparative genomics to identify genes for antigen disco...

  8. Complete Genome Sequence of a Virulent Streptococcus agalactiae Strain, 138P, Isolated from Diseased Nile Tilapia

    OpenAIRE

    Pridgeon, Julia W.; Zhang, Dunhua

    2014-01-01

    Streptococcus agalactiae strain 138P was isolated from the kidney of diseased Nile tilapia in Idaho during a 2007 streptococcal disease outbreak. The full genome sequence of S. agalactiae 138P is 1,838,701 bp. The availability of this genome will allow comparative genomics analysis to identify genes for antigen discovery and vaccine development.

  9. Fecal strings Associated with Streptococcus agalactiae Infection in Nile Tilapia, Oreochromis niloticus

    Science.gov (United States)

    Nile tilapia (Oreochromis niloticus) were experimentally-infected with Streptococcus agalactiae for several infectivity and vaccine studies. Some of the S. agalactiae-infected tilapia produced considerably longer (up to 20 cm in length) fecal waste strings than historically observed from tilapia at...

  10. Influence of Tricaine Methanesulfonate on Streptococcus agalactiae vaccination of Nile tilapia (Oreochromis niloticus)

    Science.gov (United States)

    Experiments were conducted to study the influence of tricaine methanesulfonate (MS-222) on blood glucose levels and percent cumulative survival of Nile tilapia (Oreochromis niloticus) challenged with Streptococcus agalactiae 30 days post-vaccination with S. agalactiae vaccine or sham-vaccination wit...

  11. Efficacy of an experimentally inactivated Streptococcus agalactiae vaccine in Nile tilapia (Oreochromis niloticus) reared in Brazil

    Science.gov (United States)

    Tilapia aquaculture is one of the fastest growing segments of fish production in Brazil. Nile tilapia (Oreochromis niloticus) is largely cultivated in the state of Parana, where Streptococcus agalactiae is the cause of severe disease outbreaks. The objective of this paper was to evaluate an inactiva...

  12. Using high titer West Nile intravenous immunoglobulin from selected Israeli donors for treatment of West Nile virus infection

    Directory of Open Access Journals (Sweden)

    Gottreich Ahuva

    2009-02-01

    Full Text Available Abstract Background West Nile Virus (WNV is endemic in Israel and a significant level of antibodies is present in the population due to natural exposure. Anecdotal cases suggested that the presence of anti-WNV antibodies in intravenous immunoglobulin (IVIG from Israeli donors (IVIG-IL assisted the recovery of patients with severe WNV infection. Methods To enhance the therapeutic efficacy of IVIG-IL against WNV infection, OMRIX Biopharmaceuticals, Israel, have developed a strategy for selection of plasma units from a 10% fraction of Israeli blood donors with anti-WNV antibodies. Positive units were processed into pharmaceutical grade WNV IVIG (WNIG. Following inoculation with WNV, mice received i.p. injections of different doses (0.01–8 mg/mouse of IVIG-IL or WNIG, according to the specific experimental protocol. Results WNIG was about 10 times more potent (per gr of IgG than was regular IVIG-IL when tested by ELISA and neutralization assays. In a mouse lethal WNV infection model, prophylactic treatment with WNIG was at least 5–10-fold more potent as compared to treatment with IVIG-IL. Treatment with WNIG during active encephalitis, three or four days following WNV infection, had a significant protective effect. WNIG was also very effective in protecting immunosuppressed mice. Indeed, treatment of dexamethasone-immunosuppressed mice with 0.2 or 1.0 mg WNIG 4 h after virus infection, led to 100% survival. Conclusion IVIG produced from selected plasma donated in WNV endemic regions can be used to produce WNV IVIG with superior activity for therapeutic and prophylactic measures.

  13. Long-persistence blue phosphors

    Science.gov (United States)

    Yen, William M. (Inventor); Jia, Weiyi (Inventor); Lu, Lizhu (Inventor); Yuan, Huabiao (Inventor)

    2000-01-01

    This invention relates to phosphors including long-persistence blue phosphors. Phosphors of the invention are represented by the general formula: MO . mAl.sub.2 O.sub.3 :Eu.sup.2+,R.sup.3+ wherein m is a number ranging from about 1.6 to about 2.2, M is Sr or a combination of Sr with Ca and Ba or both, R.sup.3+ is a trivalent metal ion or trivalent Bi or a mixture of these trivalent ions, Eu.sup.2+ is present at a level up to about 5 mol % of M, and R.sup.3+ is present at a level up to about 5 mol % of M. Phosphors of this invention include powders, ceramics, single crystals and single crystal fibers. A method of manufacturing improved phosphors and a method of manufacturing single crystal phosphors are also provided.

  14. [Algolization of drinkable water basins in Nizhny Tagil industrial complex].

    Science.gov (United States)

    Kul'nev, V V; Pochechun, V A

    2016-01-01

    The article covers experience of biologic rehabilitation through correction of algocenosis (algolization) of drinkable water basins in Nizhny Tagil industrial complex. Biologic rehabilitation of Chernoistochnik and Verhne-Vyisky drinkable water basins in 2011-2012 considerably improved water quality in ecologic hydrochemical and hydrobiologic parameters--that was proved by absent water contamination with blue-green algae, lower saprobiont index. Results also are significant lower concentration of pollutants--heavy metals (ferrum, manganese, copper), oil products, decreased odor and and better water quality in hydrochemical parameters to second class according to water pollution index. PMID:27048137

  15. Molecular structure, distribution, and immunology function of TNFSF13B (BAFF) in Nile tilapia (Oreochromis niloticus).

    Science.gov (United States)

    Liu, Hongzhen; Zhang, Jiaxin; Li, Jianfeng; Song, Jinyun; Zhang, Shuangquan

    2016-04-01

    B cell-activating factor (BAFF)is a member of the tumor necrosis factor (TNF) family and plays roles in B cell survival and maturation. In this study, the full-length cDNA of Nile tilapia (Oreochromis niloticus) BAFF (tBAFF) was amplified from the spleen by reverse transcription PCR (RT-PCR). The open reading frame of this cDNA encodes a protein of 261 amino acids containing a predicted transmembrane domain and a furin protease cleavage site, similar to mammalian, avian, and reptile BAFF. Real-time quantitative PCR (qPCR) analysis revealed that tBAFF is present in various tissues and is predominantly expressed in the spleen. The predicted three-dimensional (3D) structure of the Nile tilapia (Oreochromis niloticus) soluble BAFF (tsBAFF) monomer was determined by (3D) structure modeling monomeranalyzed by (3D) structure mouse counterpart. Both tsBAFF and EGFP/tsBAFF were efficiently expressed in Escherichia coli BL21 (DE3), as confirmed by SDS-PAGE and Western blot analysis. After purification, the EGFP/tsBAFF fusion protein showed a fluorescence spectrum similar to that of EGFP. Laser scanning confocal microscopy showed that EGFP/tsBAFF bound to its receptor. In vitro, tsBAFF promoted the proliferation of Nile tilapia and mouse splenic B cells together with/without a priming agent (Staphylococcus aureus Cowan 1, SAC) or anti-mouse IgM. Furthermore, tsBAFF showed a similar proliferation-stimulating effect on mouse B cells compared to msBAFF. These findings indicate that tsBAFF plays an important role in the proliferation of Nile tilapia B cells and has functional cross-reactivity among Nile tilapia and mammals. Therefore, BAFF may represent a useful factor for enhancing immunological efficacy in animals.

  16. Molecular structure, distribution, and immunology function of TNFSF13B (BAFF) in Nile tilapia (Oreochromis niloticus).

    Science.gov (United States)

    Liu, Hongzhen; Zhang, Jiaxin; Li, Jianfeng; Song, Jinyun; Zhang, Shuangquan

    2016-04-01

    B cell-activating factor (BAFF)is a member of the tumor necrosis factor (TNF) family and plays roles in B cell survival and maturation. In this study, the full-length cDNA of Nile tilapia (Oreochromis niloticus) BAFF (tBAFF) was amplified from the spleen by reverse transcription PCR (RT-PCR). The open reading frame of this cDNA encodes a protein of 261 amino acids containing a predicted transmembrane domain and a furin protease cleavage site, similar to mammalian, avian, and reptile BAFF. Real-time quantitative PCR (qPCR) analysis revealed that tBAFF is present in various tissues and is predominantly expressed in the spleen. The predicted three-dimensional (3D) structure of the Nile tilapia (Oreochromis niloticus) soluble BAFF (tsBAFF) monomer was determined by (3D) structure modeling monomeranalyzed by (3D) structure mouse counterpart. Both tsBAFF and EGFP/tsBAFF were efficiently expressed in Escherichia coli BL21 (DE3), as confirmed by SDS-PAGE and Western blot analysis. After purification, the EGFP/tsBAFF fusion protein showed a fluorescence spectrum similar to that of EGFP. Laser scanning confocal microscopy showed that EGFP/tsBAFF bound to its receptor. In vitro, tsBAFF promoted the proliferation of Nile tilapia and mouse splenic B cells together with/without a priming agent (Staphylococcus aureus Cowan 1, SAC) or anti-mouse IgM. Furthermore, tsBAFF showed a similar proliferation-stimulating effect on mouse B cells compared to msBAFF. These findings indicate that tsBAFF plays an important role in the proliferation of Nile tilapia B cells and has functional cross-reactivity among Nile tilapia and mammals. Therefore, BAFF may represent a useful factor for enhancing immunological efficacy in animals. PMID:26915306

  17. Blue Skies, Coffee Creamer, and Rayleigh Scattering

    Science.gov (United States)

    Liebl, Michael

    2010-01-01

    The first physical explanation of Earths blue sky was fashioned in 1871 by Lord Rayleigh. Many discussions of Rayleigh scattering and approaches to studying it both in and out of the classroom are available. Rayleigh scattering accounts for the blue color of the sky and the orange/red color of the Sun near sunset and sunrise, and a number of…

  18. Fluvial geoarchaeology in Avaris, the Hyksos capital in the Eastern Nile Delta (2nd Mill. B.C.)

    Science.gov (United States)

    Schmitt, Laurent; Goiran, Jean-Philippe; Tronchère, Hervé; Forstner-Muller, Irene

    2014-05-01

    Tell el-Dab'a, the ancient city of Avaris, is a key site for understanding the complex alluvial environment of the Nile delta in northern Egypt which is characterized by a palaeo-network of anastomosing branches. Avaris, the capital of the Hyksos kings, is located on the Pelusiac palaeo-branch, near the eastern margin of the delta. Avaris was an important harbour town from the late 12th Dynasty until the end of the Hyksos Period and then again in the Ramesside Period. For the first time, OSL, radiocarbon and archaeological datings have been combined on the fluvial archives. This database helps us to understand better the chrono-stratigraphy and the evolution of the palaeo-environments. Sedimentary analyses have been conducted on (i) the stratigraphy on the main harbour basin revealed by an excavation in spring 2013 (ii) the sediments that gradually silted in the pelusiac branch: coarse bedload at the bottom and sands to fine silts above. A complete bankfull cross section of the Pelusiac branch has been obtained. Thus, we get 3 important characteristics of the main branch: (1) the width, (2) the depth (3) and the palaeo-discharge has been computed. In order to get an idea of the palaeo-processes, C/M diagrams have been done thanks to the micro-granulometric data. By combining these results, a 5 millennium diachronic cartography of the evolution of the Pelusiac palaeo-branch near Avaris has been produced, providing new insights into the natural landscape evolution that may have accelerated the demise of the great city.

  19. Triboelectric Nanogenerators for Blue Energy Harvesting.

    Science.gov (United States)

    Khan, Usman; Kim, Sang-Woo

    2016-07-26

    Blue energy in the form of ocean waves offers an enormous energy resource. However, it has yet to be fully exploited in order to make it available for the use of mankind. Blue energy harvesting is a challenging task as the kinetic energy from ocean waves is irregular in amplitude and is at low frequencies. Though electromagnetic generators (EMGs) are well-known for harvesting mechanical kinetic energies, they have a crucial limitation for blue energy conversion. Indeed, the output voltage of EMGs can be impractically low at the low frequencies of ocean waves. In contrast, triboelectric nanogenerators (TENGs) are highly suitable for blue energy harvesting as they can effectively harvest mechanical energies from low frequencies (blue energy harvesting. In this Perspective, we describe some of the recent progress and also address concerns related to durable packaging of TENGs in consideration of harsh marine environments and power management for an efficient power transfer and distribution for commercial applications.

  20. Differential pathogenicity of five Streptococcus agalactiae isolates of diverse geographic origin in Nile tilapia (Oreochromis niloticus L.)

    Science.gov (United States)

    Streptococcus agalactiae is an emerging pathogen of fish and has caused significant morbidity amd mortality worldwide. The work in this study assessed whether pathogenic differences exist among isolates from different geographic locations. Nile tilapia (Oreochromis niloticus L.) were administered an...

  1. Geophysical studies in the vicinity of Blue Mountain and Pumpernickel Valley near Winnemucca, north-central Nevada

    Science.gov (United States)

    Ponce, David A.

    2012-01-01

    From May 2008 to September 2009, the U.S. Geological Survey (USGS) collected data from more than 660 gravity stations, 100 line-km of truck-towed magnetometer traverses, and 260 physical-property sites in the vicinity of Blue Mountain and Pumpernickel Valley, northern Nevada (fig. 1). Gravity, magnetic, and physical-property data were collected to study regional crustal structures as an aid to understanding the geologic framework of the Blue Mountain and Pumpernickel Valley areas, which in general, have implications for mineral- and geothermal-resource investigations throughout the Great Basin.

  2. Pseudomine, an isoxazolidone with siderophoric activity from Pseudomonas fluorescens AH2 isolated from Lake Victorian Nile Perch

    DEFF Research Database (Denmark)

    Anthoni, U.; Christophersen, C.; Nielsen, P.H.;

    1995-01-01

    A siderophore, pseudomonine, and sodium salicylate were isolated from the culture broth of iron-deficient cultures of Pseudomonas fluorescens AH2 isolated from the surface of spoiled Nile Perch from Lake Victoria......A siderophore, pseudomonine, and sodium salicylate were isolated from the culture broth of iron-deficient cultures of Pseudomonas fluorescens AH2 isolated from the surface of spoiled Nile Perch from Lake Victoria...

  3. Technique for the collection of clear urine from the Nile crocodile (Crocodylus niloticus)

    OpenAIRE

    Jan G. Myburgh; Fritz W. Huchzermeyer; Soley, John T; Dirk G. Booyse; Herman B. Groenewald; Lizette C. Bekker; Taisen Iguchi; GUILLETTE, LOUIS J.

    2012-01-01

    Urine samples can be a very useful diagnostic tool for the evaluation of animal health. In this article, a simple technique to collect urine from the Nile crocodile (Crocodylus niloticus) was described, based on a similar unpublished technique developed for the American alligator (Alligator mississippiensis) using a canine urinary catheter. With this technique, it was possible to collect relatively clean urine samples from Nile crocodiles of different sizes using canine urinary catheters or...

  4. Phenological and liver antioxidant profiles of adult Nile tilapia (Oreochromis niloticus) exposed to toxic live cyanobacterium (Microcystis aeruginosa Kützing) cells.

    Science.gov (United States)

    Khairy, Hanan M; Ibrahim, Marwa A; Ibrahem, Mai D

    2012-01-01

    Blue-green algae (cyanobacteria) constitute the greater part of the phytoplankton. Microcystis aeruginosa is amongst the most ubiquitously distributed cyanobacterial species, and almost invariably produces cyclic heptapeptide toxins called microcystins (MCs). The present study was designed to investigate the phenological and liver antioxidant profiles of the Nile tilapia Oreochromis niloticus chronically exposed to toxic live M. aeruginosa cells. Fish were grown in the absence and presence of M. aeruginosa in three different concentrations for seven days, and subsequently reared for another 30 days in the absence of the cyanobacteria. While cyanobacteria did not cause any fish mortality, there was a progressive development of yellowish discolouration in the livers of exposed fish. In the livers, the activities and levels of superoxide dismutase (SOD), lactate dehydrogenase (LDH), glutathione (GSH), and lipid peroxidation products like malondialdehyde (MDA) were elevated in response to the concentration of M. aeruginosa. Moreover, DNA fragmentation and DNA-protein crosslinks were measured. These parameters can thus be considered potential biomarkers for the fish exposure to M. aeruginosa. The present study sheds light on cyanobacterial blooms like health, environmental, and economic problem, respectively. PMID:23413757

  5. Isolation and characterization of Streptococcus spp. group B in Nile tilapias (Oreochromis niloticus reared in hapas nets and earth nurseries in the northern region of Parana State, Brazil

    Directory of Open Access Journals (Sweden)

    Salvador Rogério

    2005-01-01

    Full Text Available The objective of this study was to isolate and characterize Streptococcus spp. in Nile tilapias (Oreochromis niloticus reared in net-pens and earth nurseries. Eight intensive tilapia-rearing farms were investigated in north Paraná, Brazil from April 1st 2001 to April 30th 2002. The fish were reared in a system of hapas nets on four farms and in earth nurseries on other four farms. A total of 370 samples were analyzed of material collected from 120 fish (brain, liver, kidney, skin scrapes, ascites liquid and eye that were sown on BHI agar (Brain Heart Infusion supplemented with 1% yeast extract and sheep blood. Streptococcus spp. was isolated in 36 of the samples (18 brain, eight liver, eight kidney and two ascites liquid from 25 fish. Streptococci were isolated in both systems, almost in the same proportion. First the streptococci were characterized by the catalase and esculin test, growth in methylene blue and sodium chloride at 6.5%. They were classified in groups by the Slidex Strepto-Kit (BioMerieux, France. The phenotypic characteristics were determined by the Api 20 Strep microtest system (BioMerieux, France. The 36 Streptococcus spp. samples did not present hemolysis and were classified as Lancefield group B. Further 16 samples were identified as Streptococcus agalactiae and 20 were not identified by the Api 20 Strep, but presented the same biochemical profile described for the reference strain of Streptococcus difficile (ND-2-22.

  6. The agricultural water footprint of EU river basins

    Science.gov (United States)

    Vanham, Davy

    2014-05-01

    This work analyses the agricultural water footprint (WF) of production (WFprod,agr) and consumption (WFcons,agr) as well as the resulting net virtual water import (netVWi,agr) for 365 EU river basins with an area larger than 1000 km2. Apart from total amounts, also a differentiation between the green, blue and grey components is made. River basins where the WFcons,agr,tot exceeds WFprod,agr,tot values substantially (resulting in positive netVWi,agr,tot values), are found along the London-Milan axis. River basins where the WFprod,agr,totexceeds WFcons,agr,totare found in Western France, the Iberian Peninsula and the Baltic region. The effect of a healthy (HEALTHY) and vegetarian (VEG) diet on the WFcons,agr is assessed, as well as resulting changes in netVWi,agr. For HEALTHY, the WFcons,agr,tot of most river basins decreases (max 32%), although in the east some basins show an increase. For VEG, in all but one river basins a reduction (max 46%) in WFcons,agr,tot is observed. The effect of diets on the WFcons,agrof a river basin has not been carried out so far. River basins and not administrative borders are the key geographical entity for water management. Such a comprehensive analysis on the river basin scale is the first in its kind. Reduced river basin WFcons,agrcan contribute to sustainable water management both within the EU and outside its borders. They could help to reduce the dependency of EU consumption on domestic and foreign water resources.

  7. Tapered photonic crystal fibers for blue-enhanced supercontinuum generation

    DEFF Research Database (Denmark)

    Møller, Uffe; Sørensen, Simon Toft; Larsen, Casper;

    2012-01-01

    Tapering of photonic crystal fibers is an effective way of shifting the blue edge of a supercontinuum spectrum down in the deep-blue. We discuss the optimum taper profile for enhancing the power in the blue edge.......Tapering of photonic crystal fibers is an effective way of shifting the blue edge of a supercontinuum spectrum down in the deep-blue. We discuss the optimum taper profile for enhancing the power in the blue edge....

  8. Sharing water and benefits in transboundary river basins

    Science.gov (United States)

    Arjoon, Diane; Tilmant, Amaury; Herrmann, Markus

    2016-06-01

    The equitable sharing of benefits in transboundary river basins is necessary to solve disputes among riparian countries and to reach a consensus on basin-wide development and management activities. Benefit-sharing arrangements must be collaboratively developed to be perceived not only as efficient, but also as equitable in order to be considered acceptable to all riparian countries. The current literature mainly describes what is meant by the term benefit sharing in the context of transboundary river basins and discusses this from a conceptual point of view, but falls short of providing practical, institutional arrangements that ensure maximum economic welfare as well as collaboratively developed methods for encouraging the equitable sharing of benefits. In this study, we define an institutional arrangement that distributes welfare in a river basin by maximizing the economic benefits of water use and then sharing these benefits in an equitable manner using a method developed through stakeholder involvement. We describe a methodology in which (i) a hydrological model is used to allocate scarce water resources, in an economically efficient manner, to water users in a transboundary basin, (ii) water users are obliged to pay for water, and (iii) the total of these water charges is equitably redistributed as monetary compensation to users in an amount determined through the application of a sharing method developed by stakeholder input, thus based on a stakeholder vision of fairness, using an axiomatic approach. With the proposed benefit-sharing mechanism, the efficiency-equity trade-off still exists, but the extent of the imbalance is reduced because benefits are maximized and redistributed according to a key that has been collectively agreed upon by the participants. The whole system is overseen by a river basin authority. The methodology is applied to the Eastern Nile River basin as a case study. The described technique not only ensures economic efficiency, but may

  9. Optimization of a Nile Red method for rapid lipid determination in autotrophic, marine microalgae is species dependent.

    Science.gov (United States)

    Balduyck, Lieselot; Veryser, Cedrick; Goiris, Koen; Bruneel, Charlotte; Muylaert, Koenraad; Foubert, Imogen

    2015-11-01

    Several studies have been conducted to develop rapid methods for quantification of lipid content in microalgae, as an alternative for time consuming gravimetric methods. Different studies showed that lipid staining with Nile Red in whole cell suspensions and subsequently quantification by the use of a spectrofluorometric device is a promising method, but a profound optimization and validation is rare. It has already been proven that the correlation curve for quantification is species dependent, but it has not yet been investigated whether this is also the case for the optimization of the Nile Red assay protocol. Therefore, two autotrophic, marine microalgae, Nannochloropsis oculata and T-Isochrysis lutea, strongly differing in e.g. cell wall structure, were selected in this study to investigate whether optimization of the Nile Red assay is species dependent. Besides this, it was checked for one of these species, Nannochloropsis, whether the lipid content, determined by the Nile Red assay, could indeed be correlated with the neutral and/or total lipid content determined by gravimetric methods. It was found that optimization of the Nile Red assay was strongly species dependent. Consequently, optimization has to be done for each species before using the assay. For Nannochloropsis, a good correlation was found between total and neutral lipid content obtained by the Nile Red assay and by gravimetric methods.

  10. The biology, ecology and impact of the Nile perch, Lates niloticus in lakes Victoria, Kyoga and Nabugabo and the future of the fisheries

    OpenAIRE

    Ogutu-Ohwayo, R.

    2000-01-01

    Nile perch (Mputa), Lates niloticus was introduced into Lakes Victoria and Kyoga from lake Albert to increase fish production of these lakes by feeding on and converting the small sized haplochromines (Nkejje) which were abundant in these lakes into a larger table fish. It was, however, feared that Nile perch would prey on and deplete stocks of the native fishes and affect fish species diversity. Nile perch became well established and is currently among the three most important commercial spe...

  11. Blue jays nest in an unusual structure

    Science.gov (United States)

    Muths, Erin L.; Lyons, Curtis P.; Sedgwick, James A.

    2007-01-01

    We describe a successful Blue Jay (Cyanocitta cristata) nest in an unusual structure on the side of a building.  The nest was located near the edge of the species' range along the Front Range of the Rocky Mountains in Colorado.  The nest was completely obvious, suggesting that the structure itself provided adequate cover and sercurity for the jays.  Blue Jays appear to be declining in some areas of the United States such as the Southeast.  Structures such as the one we describe may be more useful in attracting Blue Jays than the nesting platforms available commercially.

  12. A blue/green water-based accounting framework for assessment of water security

    Science.gov (United States)

    Rodrigues, Dulce B. B.; Gupta, Hoshin V.; Mendiondo, Eduardo M.

    2014-09-01

    A comprehensive assessment of water security can incorporate several water-related concepts, while accounting for Blue and Green Water (BW and GW) types defined in accordance with the hydrological processes involved. Here we demonstrate how a quantitative analysis of provision probability and use of BW and GW can be conducted, so as to provide indicators of water scarcity and vulnerability at the basin level. To illustrate the approach, we use the Soil and Water Assessment Tool (SWAT) to model the hydrology of an agricultural basin (291 km2) within the Cantareira Water Supply System in Brazil. To provide a more comprehensive basis for decision making, we analyze the BW and GW-Footprint components against probabilistic levels (50th and 30th percentile) of freshwater availability for human activities, during a 23 year period. Several contrasting situations of BW provision are distinguished, using different hydrological-based methodologies for specifying monthly Environmental Flow Requirements (EFRs), and the risk of natural EFR violation is evaluated by use of a freshwater provision index. Our results reveal clear spatial and temporal patterns of water scarcity and vulnerability levels within the basin. Taking into account conservation targets for the basin, it appears that the more restrictive EFR methods are more appropriate than the method currently employed at the study basin. The blue/green water-based accounting framework developed here provides a useful integration of hydrologic, ecosystem and human needs information on a monthly basis, thereby improving our understanding of how and where water-related threats to human and aquatic ecosystem security can arise.

  13. Outcomes of West Nile encephalitis patients after 1 year of West Nile encephalitis outbreak in Kerala, India: A follow-up study.

    Science.gov (United States)

    Balakrishnan, Anukumar; Thekkekara, Romy Jose; Tandale, Babasheb V

    2016-11-01

    We reported an acute encephalitis syndrome outbreak in Alappuzha district in Kerala, India during the year 2011. The etiology was confirmed to be West Nile virus lineage 1. Many encephalitis patients from this outbreak exhibited neurological sequelae post recovery. This study was aimed to assess the clinical outcomes of West Nile encephalitis confirmed case-patients after 1 year of acute illness. Forty West Nile virus confirmed encephalitis patients were selected from the 2011 outbreak was included in this study. Out of 40 cases, only 30 survived after 12 months. Among these 30 recovered case-patients, 27 (90%) consented for clinical follow-up and 23 (73.67%) of them consented for assessment of cognitive impairment and deposition of blood sample for antibody testing. The most common symptom observed in these patients was fatigue (25.93%). Other symptoms included dizziness (7.4%), decreased sense of hearing (7.4%) and decreased sense of smell (7.4%). Reduced power in limbs was found in 33.33% of the cases. Most of the patients (23.1%) were dependent on others for normal daily living activities. The patients also had probable risk of poor cognition (29.41%) and dementia (57.14%). None of the patients were positive for WNV specific IgM at 12 months post onset of disease. The study concluded that the long-term sequelae were noticed in WNV positive patients. Prevention effort should be focused on the elderly (≥60 years old) people who have a higher risk of severe sequelae. The state health authorities should create awareness among people in order to prevent the transmission of disease. J. Med. Virol. 88:1856-1861, 2016. © 2016 Wiley Periodicals, Inc.

  14. Analysis and localization of blue whale vocalizations in the Solomon Sea using waveform amplitude data.

    Science.gov (United States)

    Frank, Scott D; Ferris, Aaron N

    2011-08-01

    During the Woodlark Basin seismic experiment in eastern Papua New Guinea (1999-2000), an ocean-bottom seismic array recorded marine mammal vocalizations along with target earthquake signals. The array consisted of 14 instruments, 7 of which were three-component seismometers with a fourth component hydrophone. They were deployed at 2.0-3.2 km water depth and operated from September 1999 through February 2000. While whale vocalizations were recorded throughout the deployment, this study focuses on 3 h from December 21, 1999 during which the signals are particularly clear. The recordings show a blue whale song composed of a three-unit phrase. That song does not match vocalization characteristics of other known Pacific subpopulations and may represent a previously undocumented blue whale song. Animal tracking and source level estimates are obtained with a Bayesian inversion method that generates probabilistic source locations. The Bayesian method is augmented to include travel time estimates from seismometers and hydrophones and acoustic signal amplitude. Tracking results show the whale traveled northeasterly over the course of 3 h, covering approximately 27 km. The path followed the edge of the Woodlark Basin along a shelf that separates the shallow waters of the Trobriand platform from the deep waters of the basin.

  15. Properties of blue-stained wood

    Directory of Open Access Journals (Sweden)

    Miha Humar

    2008-07-01

    Full Text Available Discoloration of wood is frequently caused by blue-stain fungi. Among them Aureobasidium pullulans and Sclerophoma pithyophila are reported as the most important staining organism. In previous researches, it was generally considered that blue-stain fungi do not influence mechanical properties. However, there were some opposite results published as well. In order to elucidate this issue, specimens made of Scots pine (Pinus sylvestris sapwood were exposed to two blue stain fungi A. pullulans and S. pithyophila for periods between two and eight weeks. FTIR, weight, colour and non-destructive modulus of elasticity measurements were performed before and after exposure. The results showed that blue stain fungi, besides considerable discoloration, do not cause any significant damage to wood. Surprisingly the non-destructive MoE analysis showed that modulus of elasticity even slightly increase after fungal exposure.

  16. Blue Ribbon Panel Report - BRP - Cancer Moonshot

    Science.gov (United States)

    The Blue Ribbon Panel Report outlines 10 recommendations to accelerate progress against cancer. The panel was established to ensure that the Cancer Moonshot's approaches are grounded in the best science.

  17. Blue Ribbon Panel 2016 Video Playlist

    Science.gov (United States)

    Blue Ribbon Panel members discuss recommendations from the panel report that was presented to the National Cancer Advisory Board on September 7, 2016. The playlist includes an overview video and 10 videos on the specific recommendations.

  18. Blue Ocean Strategy and marketing Icelandic fish

    OpenAIRE

    Sigrún Guðbjartsdóttir 1976

    2012-01-01

    The aim of the thesis is to explore if practice of Blue Ocean Strategy, through value innovation, or certain tools and framework of the strategy can be useful for Icelandic fish marketing companies. Blue Ocean Strategy is an innovative strategy that pushes companies to look beyond conventional boundaries of an industry and discover new market space through value innovation and consequently make competition irrelevant. Data was gathered through qualitative research methods, interviews as we...

  19. Blue Flag: a Symbol of Environmental Protection

    Directory of Open Access Journals (Sweden)

    Ioan Petroman

    2010-10-01

    Full Text Available Blue Flag is a high standard symbol of environmental protection and it is awarded to the beaches and agreement ports by the Foundation of Education for the Environment. The beaches having been awarded this distinction warrant particular protection for their visitors, which is a particular point of tourism attractiveness: the result, they are preferred by tourists and, therefore, by tour operators selling tourism packages for the littoral. In 2009, Romanian beaches were not awarded any Blue Flags.

  20. Blue emitting organic semiconductors under high pressure

    DEFF Research Database (Denmark)

    Knaapila, Matti; Guha, Suchismita

    2016-01-01

    This review describes essential optical and emerging structural experiments that use high GPa range hydrostatic pressure to probe physical phenomena in blue-emitting organic semiconductors including π-conjugated polyfluorene and related compounds. The work emphasizes molecular structure and inter......This review describes essential optical and emerging structural experiments that use high GPa range hydrostatic pressure to probe physical phenomena in blue-emitting organic semiconductors including π-conjugated polyfluorene and related compounds. The work emphasizes molecular structure...

  1. Blue Whales Respond to Anthropogenic Noise

    OpenAIRE

    Mariana L Melcón; Amanda J Cummins; Kerosky, Sara M; Lauren K Roche; Wiggins, Sean M.; John A. Hildebrand

    2012-01-01

    Anthropogenic noise may significantly impact exposed marine mammals. This work studied the vocalization response of endangered blue whales to anthropogenic noise sources in the mid-frequency range using passive acoustic monitoring in the Southern California Bight. Blue whales were less likely to produce calls when mid-frequency active sonar was present. This reduction was more pronounced when the sonar source was closer to the animal, at higher sound levels. The animals were equally likely to...

  2. Development of Nile red-functionalized magnetic silica nanoparticles for cobalt ion sensing and entrapping

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Tao; Lv, Yanlin; Liu, Heng; Lv, Yi; Tian, Zhiyuan, E-mail: zytian@ucas.ac.cn [University of Chinese Academy of Sciences (UCAS), School of Chemistry and Chemical Engineering (China)

    2013-09-15

    A new type of hybrid nanoparticles (NPs) with combined magnetic and fluorescent properties in single particle was developed by incorporating magnetic silica NPs with highly fluorescent Nile red dyes. These NPs clearly exhibit Co{sup 2+} ion entrapping ability in aqueous milieu and Co{sup 2+}-induced fluorescence enhancement features with high selectivity owing to the Co{sup 2+}-triggered inhibition on the photoinduced electron transfer progress in the efficient fluorophore (Nile red derivative). Moreover, these dual-functional NPs display superparamagnetic features and the motion of these fluorescent NPs can be induced by the application of an external magnetic field, enabling a facile separation/removal of toxic Co{sup 2+} ion from the aqueous milieu and real-time monitoring via fluorescence measurements.

  3. Use of fish processing waste as protein source in diet for Nile tilapia (Orechromis niloticus

    Directory of Open Access Journals (Sweden)

    Chotipuntu, P.

    2005-02-01

    Full Text Available Five diets were prepared using fish processing waste meal (FMFP to replace fish meal (FM at inclusion levels of 0, 25, 50, 75 and 100%. Frog diet was used as a control diet. Nile tilapia (Oreochromis niloticus were reared in laboratory conditions for 8 weeks. It was found that substitution levels of protein from FMFP in the tested diets reduced growth and feed efficiency of tilapia (p<0.05. However, the differences looks like significant trend especially that between the 100% substitution level and the frog diet. Substitution of FM by FMFD at 75% reduced cost of feed by 15.35%. It was concluded that up to 75% inclusion of FMFD in the diet of tilapia could support normal growth of Nile tilapia with the potential for substitution of FM.

  4. Crystallization and preliminary X-ray diffraction analysis of West Nile virus

    International Nuclear Information System (INIS)

    Crystals of infectious West Nile virus were obtained and diffracted at best to about 25 Å resolution. Preliminary analysis of the diffraction pattern suggested tight hexagonal packing of the intact virus. West Nile virus, a human pathogen, is closely related to other medically important flaviviruses of global impact such as dengue virus. The infectious virus was purified from cell culture using polyethylene glycol (PEG) precipitation and density-gradient centrifugation. Thin amorphously shaped crystals of the lipid-enveloped virus were grown in quartz capillaries equilibrated by vapor diffusion. Crystal diffraction extended at best to a resolution of about 25 Å using synchrotron radiation. A preliminary analysis of the diffraction images indicated that the crystals had unit-cell parameters a ≃ b ≃ 480 Å, γ = 120°, suggesting a tight hexagonal packing of one virus particle per unit cell

  5. Prevalence of West Nile virus in Mashhad, Iran:A population-based study

    Institute of Scientific and Technical Information of China (English)

    Zahra Meshkat; Sadegh Chinikar; MohammadTaghi Shakeri; Lida Manavifar; Maryam Moradi; Hessam Mirshahabi; Tahmineh Jalali; Sahar Khakifirouz; Nariman Shahhosseini

    2015-01-01

    Objective:To evaluate the prevalence of West Nile virus seropositivity in the general population of Mashhad, Northeast of Iran.Methods:One hundred and eighty two individuals living in the city of Mashhad were studied using cluster sampling method. Both IgM and IgG antibodies against WNV were detected by ELISA method.Results:In this study, the overall IgG seroprevalence of positive West Nile virus was 11%; however, IgM antibody was not found in the participants.Conclusions:Our study suggested that the prevalence rate of West virus is considerable in Mashhad city. It seems necessary for clinicians and health care workers to be aware of WNV infection in the Northeast Iran.

  6. Evaluating red-cockaded woodpeckers for exposure to West Nile Virus and blood parasites

    Science.gov (United States)

    Dusek, R.J.; Richardson, D.; Egstad, K.F.; Heisey, Dennis M.

    2006-01-01

    A marked decline in the Picoides borealis (Red-cockaded Woodpecker [RCW]) population at Noxubee National Wildlife Refuge, MS, was observed in 2002. Demographic changes - including absence of hatch-year birds, decreases in size of known groups, and loss of known groups-were identified during annual fall surveys and are uncharacteristic of RCW populations. In 2003, a serosurvey of 28 adult RCWs was conducted to investigate the presence of West Nile virus (WNV) exposure in the population, possibly providing insight into whether WNV may have been responsible for this decline. Blood smears were also examined from these birds for blood parasites. We found no evidence of West Nile virus exposure or blood parasites in any of the RCWs sampled. Further monitoring of the RCW population and WNV activity in other species at Noxubee NWR is recommended to further evaluate the potential role of WNV and blood parasites in their decline.

  7. Le lupus systémique juvénile familial: à propos de deux familles

    OpenAIRE

    Krich, Sanaa; Inani, Kawtar; Meziane, Mariame; Souilmi, Fatima Zohta; Atmani, Samir; Hida, Mustapha; Harmouch, Taoufik; Amarti, Afaf; Mernissi, Fatima Zohra

    2015-01-01

    Le lupus érythémateux systémique (LES) juvénile est une connectivite rare, d’évolution plus sévère que chez l'adulte. Les cas familiaux sont exceptionnels. Il s'agissait de deux familles (5 patients atteints), chez qui on a objectivé un LES juvénile chez deux sæurs âgées de 14 ans et 6 ans respectivement chez la première famille, deux frères, âgés de 20 ans et 6 ans respectivement plus une sæur âgée de 10 ans chez la deuxième famille. Dans tout les cas le diagnostic de lupus systémique a été ...

  8. Does sex influence intraspecific aggression and dominance in Nile tilapia juveniles?

    Science.gov (United States)

    Pinho-Neto, Cândido Ferreira; Miyai, Caio Akira; Sanches, Fabio Henrique Carretero; Giaquinto, Percília Cardoso; Delicio, Helton Carlos; Barcellos, Leonardo José Gil; Volpato, Gilson Luiz; Barreto, Rodrigo Egydio

    2014-06-01

    Although sex of mature fish is known to influence aggression, this issue has so far been neglected in juveniles. Here, we tested this sex effect and showed that it does not significantly affect intraspecific aggression in juveniles of the cichlid Nile tilapia. To reach this conclusion, we measured the latency period before onset of confrontation, the frequency and types of aggressive interactions, the duration of a dispute, and the probability of becoming dominant. This was done on pairs of Nile tilapia that varied by sex: females×females, males×males, and females×males. In a double blind approach, after pairing, the sex of each individual was histologically verified and contrasted with behavioral data.

  9. Water Quality Assessment of the River Nile System:An Overview

    Institute of Scientific and Technical Information of China (English)

    RIFAAT A. WAHAAB; MOHAMED I. BADAWY

    2004-01-01

    Objectives The main objective of the present article is to assess and evaluate the characteristics of the Nile water system, and identify the major sources of pollution and its environmental and health consequences. The article is also aimed to highlight the importance of water management via re-use and recycle of treated effluents for industrial purpose and for cultivation of desert land. Method An intensive effort was made by the authors to collect, assess and compile the available data about the River Nile. Physico-chemical analyses were conducted to check the validity of the collected data. For the determination of micro-pollutants, Gas Chromatography (GC) and High Performance Liquid Chromatography (HPLC) were used. Heavy metals were also determined to investigate the level of industrial pollution in the river system. Results The available data revealed that the river receives a large quantity of industrial, agriculture and domestic wastewater. It is worth mentioning that the river is still able to recover in virtually all the locations, with very little exception. This is due to the high dilution ratio. The collected data confirmed the presence of high concentrations of chromium and manganese in all sediment samples. The residues of organo-chlorine insecticides were detected in virtually all locations. However, the levels of such residues are usually below the limit set by the WHO for use as drinking water. The most polluted lakes are Lake Maryut and Lake Manzala.Groundwater pollution is closely related to adjacent (polluted) surface waters. High concentrations of nutrients, E. coli, sulfur, heavy metals, etc. have been observed in the shallow groundwater, largely surpassing WHO standards for drinking water use. Conclusion A regular and continuous monitoring scheme shall be developed for the River Nile system. The environmental law shall be enforced to prohibit the discharge of wastewater (agricultural, domestic or industrial) to River Nile system.

  10. Understanding farmers' adaptation to water scarcity : a case study from the western Nile Delta, Egypt

    OpenAIRE

    Ghazouani, W.; Molle, François; Swelam, A.; Rap, E.; Abdo, A.

    2014-01-01

    This study was undertaken to analyze farmers' adaption to water scarcity in the command area of a secondary canal in the Nile Delta of Egypt. The results revealed that farmers' responses were driven by a multiplicity of factors, beyond water scarcity or profit maximization. These additional factors include food security of the family, risk management, social capital and history of farmers, and most unexpectedly the collective dimension of crop choice. The findings of this study expose the lim...

  11. Animal viral diseases and global change: Bluetongue and West Nile fever as paradigms

    Directory of Open Access Journals (Sweden)

    Miguel Angel eJimenez-Clavero

    2012-06-01

    Full Text Available Environmental changes have an undoubted influence on the appearance, distribution and evolution of infectious diseases, and notably on those transmitted by vectors. Global change refers to environmental changes arising from human activities affecting the fundamental mechanisms operating in the biosphere. This paper discusses the changes observed in recent times with regard to some important arboviral (arthropod-borne viral diseases of animals, and the role global change could have played in these variations. Two of the most important arboviral diseases of animals, bluetongue and West Nile fever/encephalitis, have been selected as models. In both cases, in the last 15 years an important leap forward has been observed, which has lead to considering them emerging diseases in different parts of the world. Bluetongue, affecting domestic ruminants, has recently afflicted livestock in Europe in an unprecedented epizootic, causing enormous economic losses. West Nile fever/encephalitis affects wildlife (birds, domestic animals (equines and humans, thus, beyond the economic consequences of its occurrence, as a zoonotic disease, it poses an important public health threat. West Nile virus has expanded in the last 12 years worldwide, and particularly in the Americas, where it first occurred in 1999, extending throughout the Americas relentlessly since then, causing a severe epidemic of disastrous consequences for public health, wildlife and livestock. In Europe, West Nile virus is known long time ago, but it is since the last years of the XXth century that its incidence has risen substantially. Circumstances such as global warming, changes in land use and water management, increase in travel, trade of animals, and others, can have an important influence in the observed changes in both diseases. The following question is raised: What is the contribution of global changes to the current increase of these diseases in the world?

  12. Selection for growth of Nile tilapia (Oreochromis niloticus L.) in low-input environments

    NARCIS (Netherlands)

    Charo-Karisa, H.

    2006-01-01

    Nile tilapia,Oreochromis niloticus,is one of the most important species farmed in the world and is the mainstay of many res

  13. Vector competence of selected North American Culex and Coquillettidia mosquitoes for West Nile virus.

    OpenAIRE

    Sardelis, M. R.; Turell, M.J.; Dohm, D. J.; O'Guinn, M. L.

    2001-01-01

    To control West Nile virus (WNV), it is necessary to know which mosquitoes are able to transmit this virus. Therefore, we evaluated the WNV vector potential of several North American mosquito species. Culex restuans and Cx. salinarius, two species from which WNV was isolated in New York in 2000, were efficient laboratory vectors. Cx. quinquefasciatus and Cx. nigripalpus from Florida were competent but only moderately efficient vectors. Coquillettidia perturbans was an inefficient laboratory v...

  14. Flaviviruses, an expanding threat in public health: focus on Dengue, West Nile, and Japanese encephalitis virus

    OpenAIRE

    Daep, Carlo Amorin; Muñoz-Jordán, Jorge L.; Eugenin, Eliseo Alberto

    2014-01-01

    The flaviviruses Dengue, West Nile, and Japanese encephalitis represent three major mosquito-borne viruses worldwide. These pathogens impact the lives of millions of individuals and potentially could affect non-endemic areas already colonized by mosquito vectors. Unintentional transport of infected vectors (Aedes and Culex sp), traveling within endemic areas, rapid adaptation of the insects into new geographic locations, climate change, and lack of medical surveillance have greatly contribute...

  15. Nile Red staining of phytoplankton neutral lipids: species-specific fluorescence kinetics in various solvents

    OpenAIRE

    Natunen, Katariina; Seppälä, Jukka; Schwenk, Dagmar; Rischer, Heiko; Spilling, Kristian; Tamminen, Timo

    2014-01-01

    Nile Red (NR) staining potentially offers a simple method for monitoring lipid accumulation in microalgal cultivation. However, variable staining efficiencies and methods have been reported. The effect of dimethyl sulfoxide (DMSO), ethylene glycol (EG) and glycerol on NR penetration with four different phytoplankton species representing different taxonomical groups was studied. Treatment with the solvents enhanced the NR fluorescence of the diatom Phaeodactylum tricornutum during kinetic fluo...

  16. Antibodies to West Nile Virus in Wild and Farmed Crocodiles in Southeastern Mexico

    OpenAIRE

    Machain-Williams, Carlos; Padilla-Paz, Sergio E.; Weber, Manuel; Cetina-Trejo, Rosa; Juarez-Ordaz, José Alfredo; Loroño-Pino, María Alba; Ulloa, Armando; Wang, Chong; Garcia-Rejon, Julián; Blitvich, Bradley J.

    2013-01-01

    Surveillance for evidence of West Nile virus (WNV) infection in Morelet’s crocodiles (Crocodylus moreletii) was conducted in Campeche State, Mexico, in 2007. Sera from 62 crocodiles (32 free-ranging and 30 captive) were assayed for antibodies to WNV by epitope-blocking enzyme-linked immunosorbent assay. Antibodies to WNV were detected in 13 (41%) wild and nine (30%) captive crocodiles, and the overall antibody prevalence was 35%. Although evidence of WNV infection in captive crocodiles has be...

  17. Anti-diabetic effects of palm fruit juice in the Nile rat (Arvicanthis niloticus)

    OpenAIRE

    Bolsinger, Julia; Pronczuk, Andrzej; Sambanthamurthi, Ravigadevi; Hayes, K. C.

    2014-01-01

    With the increasing incidence of metabolic diseases, numerous bioactive phytochemicals have been proffered in the dietary prevention of these conditions. Palm fruit juice (PFJ) possesses bioactive phenolic compounds (referred to as oil palm phenolics; OPP) that may deter diabetes. The objective of the present experiments was to document the degree to which PFJ reduces diabetes symptoms in a variety of circumstances in the Nile rat (Arvicanthis niloticus), a novel model for carbohydrate-induce...

  18. Aerosol climatology over Nile Delta based on MODIS, MISR and OMI satellite data

    OpenAIRE

    H. S. Marey; J. C. Gille; H. M. El-Askary; Shalaby, E. A.; M. E. El-Raey

    2011-01-01

    Since 1999 Cairo and the Nile delta region have suffered from air pollution episodes called the "black cloud" during the fall season. These have been attributed to either burning of agriculture waste or long-range transport of desert dust. Here we present a detailed analysis of the optical and microphysical aerosol properties, based on satellite data. Monthly mean values of Moderate Resolution Imaging Spectroradiometer (MODIS) aerosol optical depth (AOD) at 550 nm were examined for the 10 yr ...

  19. On the potential roles of ticks and migrating birds in the ecology of West Nile virus

    OpenAIRE

    Hagman, Karl; Barboutis, Christos; Ehrenborg, Christian; Fransson, Thord; Thomas G.T. Jaenson; Lindgren, Per-Eric; Lundkvist, Åke; Nyström, Fredrik; Waldenström, Jonas; Salaneck, Erik

    2014-01-01

    Background: Mosquitoes are the primary vectors of West Nile virus (WNV). Ticks have, however, been suggested to be potential reservoirs of WNV. In order to investigate their role in the spread of the virus, ticks, which had been collected from birds migrating northwards from Africa to Europe, were analyzed for the potential presence of WNV-RNA.Methods: On the Mediterranean islands Capri and Antikythira a total of 14,824 birds were captured and investigated from which 747 ticks were collected....

  20. Spatio-temporal patterns of distribution of West Nile virus vectors in eastern Piedmont Region, Italy

    OpenAIRE

    Bisanzio Donal; Giacobini Mario; Bertolotti Luigi; Mosca Andrea; Balbo Luca; Kitron Uriel; Vazquez-Prokopec Gonzalo M

    2011-01-01

    Abstract Background West Nile Virus (WNV) transmission in Italy was first reported in 1998 as an equine outbreak near the swamps of Padule di Fucecchio, Tuscany. No other cases were identified during the following decade until 2008, when horse and human outbreaks were reported in Emilia Romagna, North Italy. Since then, WNV outbreaks have occurred annually, spreading from their initial northern foci throughout the country. Following the outbreak in 1998 the Italian public health authority def...