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Sample records for blue nile abay

  1. Building Climate Resilience in the Blue Nile/Abay Highlands: A Role for Earth System Sciences

    PubMed Central

    Zaitchik, Benjamin F.; Simane, Belay; Habib, Shahid; Anderson, Martha C.; Ozdogan, Mutlu; Foltz, Jeremy D.

    2012-01-01

    The Blue Nile (Abay) Highlands of Ethiopia are characterized by significant interannual climate variability, complex topography and associated local climate contrasts, erosive rains and erodible soils, and intense land pressure due to an increasing population and an economy that is almost entirely dependent on smallholder, low-input agriculture. As a result, these highland zones are highly vulnerable to negative impacts of climate variability. As patterns of variability and precipitation intensity alter under anthropogenic climate change, there is concern that this vulnerability will increase, threatening economic development and food security in the region. In order to overcome these challenges and to enhance sustainable development in the context of climate change, it is necessary to establish climate resilient development strategies that are informed by best-available Earth System Science (ESS) information. This requirement is complicated by the fact that climate projections for the Abay Highlands contain significant and perhaps irreducible uncertainties. A critical challenge for ESS, then, is to generate and to communicate meaningful information for climate resilient development in the context of a highly uncertain climate forecast. Here we report on a framework for applying ESS to climate resilient development in the Abay Highlands, with a focus on the challenge of reducing land degradation. PMID:22470302

  2. Building climate resilience in the Blue Nile/Abay Highlands: Part II-arole for earth system sciences

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Blue Nile (Abay) Highlands of Ethiopia are characterized by significant interannual climate variability, dissected topography and associated local climate contrasts, erosive rains and erodible soils, and intense land pressure due to an increasing population and an economy that is almost entirely...

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

    PubMed Central

    Simane, Belay; Zaitchik, Benjamin F.; Mesfin, Desalegn

    2012-01-01

    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 Mountain study

  4. Hydrological Response to Climate Change for Gilgel Abay River, in the Lake Tana Basin - Upper Blue Nile Basin of Ethiopia

    PubMed Central

    Dile, Yihun Taddele; Berndtsson, Ronny; Setegn, Shimelis G.

    2013-01-01

    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. PMID:24250755

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

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

    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 more than 70% of total Nile water flow originates from the Ethiopian highlands. Stable isotope compositions in precipitation, spring water and streamflow were analysed (i) to characterise 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 on a seasonal timescale. The results show that the isotopic composition of precipitation exhibits marked seasonal variations, which suggests different sources of moisture generation for the rainfall in the study area. The Atlantic-Indian Ocean, Congo basin, Upper White Nile and the Sudd swamps are 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 in the isotopic composition is influenced by the amount effect as depicted by moderate coefficients of determination on a monthly timescale (R2 varies from 0.38 to 0.68) and weak regression coefficients (R2 varies from 0.18 to 0.58) for the altitude and temperature effects. A mean altitude effect accounting for -0.12‰/100 m for 18O and -0.58‰/100 m for 2H was discernible in precipitation isotope composition. Results from the hydrograph separation on a seasonal timescale 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 catchments, respectively. Moreover, the stable isotope compositions of streamflow samples were damped compared to the input function of

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

    NASA Astrophysics Data System (ADS)

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

    2013-08-01

    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 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 and this damping was

  7. Inter-annual and seasonal trends of vegetation condition in the Upper Blue Nile (Abay) Basin: dual-scale time series analysis

    NASA Astrophysics Data System (ADS)

    Teferi, E.; Uhlenbrook, S.; Bewket, W.

    2015-09-01

    A long-term decline in ecosystem functioning and productivity, often called land degradation, is a serious environmental challenge to Ethiopia that needs to be understood so as to develop sustainable land use strategies. This study examines inter-annual and seasonal trends of vegetation cover in the Upper Blue Nile (UBN) or Abbay Basin. The Advanced Very High Resolution Radiometer (AVHRR)-based Global Inventory, Monitoring, and Modeling Studies (GIMMS) normalized difference vegetation index (NDVI) was used for long-term vegetation trend analysis at low spatial resolution. Moderate Resolution Imaging Spectroradiometer (MODIS) NDVI data (MOD13Q1) were used for medium-scale vegetation trend analysis. Harmonic analyses and non-parametric trend tests were applied to both GIMMS NDVI (1981-2006) and MODIS NDVI (2001-2011) data sets. Based on a robust trend estimator (Theil-Sen slope), most parts of the UBN (~ 77 %) showed a positive trend in monthly GIMMS NDVI, with a mean rate of 0.0015 NDVI units (3.77 % yr-1), out of which 41.15 % of the basin depicted significant increases (p < 0.05), with a mean rate of 0.0023 NDVI units (5.59 % yr-1) during the period. However, the MODIS-based vegetation trend analysis revealed that about 36 % of the UBN showed a significant decreasing trend (p < 0.05) over the period 2001-2011 at an average rate of 0.0768 NDVI yr-1. This indicates that the greening trend of the vegetation condition was followed by decreasing trend since the mid-2000s in the basin, which requires the attention of land users and decision makers. Seasonal trend analysis was found to be very useful to identify changes in vegetation condition that could be masked if only inter-annual vegetation trend analysis was performed. Over half (60 %) of the Abay Basin was found to exhibit significant trends in seasonality over the 25-year period (1982-2006). About 17 and 16 % of the significant trends consisted of areas experiencing a uniform increase in NDVI throughout the year

  8. Climate resilience in the Blue Nile Highlands: defining a role for Earth System Sciences

    NASA Astrophysics Data System (ADS)

    Zaitchik, B. F.; Simane, B.

    2011-12-01

    The Blue Nile (Abay) Highlands of Ethiopia are characterized by significant interannual climate variability, dissected topography and associated local climate contrasts, erosive rains and erodible soils, and intense land pressure due to an increasing population and an economy that is almost entirely dependent on smallholder, low-input agriculture. As a result, these highland zones are highly vulnerable to negative impacts of climate variability. As most climate projections indicate that climate variability and intensity of rain events will increase in the coming decades, there is concern that vulnerability will increase, threatening economic development and food security in the region. In order to overcome these challenges and to enhance sustainable development in the context of climate change, it is necessary to develop climate resilient development strategies that are informed by best-available earth system science information on climate change impacts. This requirement is complicated by the fact that climate projections for the Abay Highlands contain significant and perhaps irreducible uncertainties. A critical challenge for Earth System Science (ESS), then, is to generate and to communicate meaningful information for climate resilient development in the context of a highly uncertain climate forecast. Here we report on a framework for applying ESS to climate resilient development in the Abay Highlands, with a focus on the challenge of reducing land degradation for improved food and water security.

  9. Visualising DNA in Classrooms Using Nile Blue

    ERIC Educational Resources Information Center

    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…

  10. Nile Blue derivatives as lysosomotropic photosensitizers

    NASA Astrophysics Data System (ADS)

    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.

  11. Building hydrologic information systems to promote climate resilience in the Blue Nile/Abay higlands

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Climate adaptation requires information about climate and land-surface conditions – spatially distributed, and at scales of human influence (the field scale). This article describes a project aimed at combining meteorological data, satellite remote sensing, hydrologic modeling, and downscaled clima...

  12. Blue Nile Rainfall Experiment: Validation Results

    NASA Astrophysics Data System (ADS)

    Gebremichael, M.

    2014-12-01

    The accuracy of three widely-used, near-global, high-resolution satellite rainfall products (CMORPH, TMPA-RT v7, TMPA-RP v7) is assessed over the Blue Nile River Basin, a basin characterized by complex terrain and tropical monsoon. The assessment is made using dense experimental networks of rain gauges deployed at two, 0.25°×0.25°, sites that represent contrasting topographic features: the lowland plain (mean elevation of 719 m.a.s.l.) site and the highland mountain (mean elevation of 2268 m.a.s.l.). The investigation period covers the summer seasons of 2012 through 2014. Compared to the highland mountain site, the lowland plain site exhibits marked extremes of rain intensity, higher rain intensity, 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. The satellite products underestimate the heavy rain rates at both sites. Both sites have uncertainty (root mean square error) values greater than 100% for 3 hour accumulations of less than 5 mm, or daily accumulations of less than 10 mm, and the uncertainty values decrease with increasing rainfall accumulation. Among the satellite products, CMORPH suffers from a large positive bias at the lowland plain site, and TMPA-RP and TMPA-RT miss a large number of rainfall events that contribute nearly half of the total rainfall at the lowland plain.

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

    NASA Astrophysics Data System (ADS)

    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.

  14. From non-covalent binding to irreversible DNA lesions: nile blue and nile red as photosensitizing agents

    PubMed Central

    Gattuso, Hugo; Besancenot, Vanessa; Grandemange, Stéphanie; Marazzi, Marco; Monari, Antonio

    2016-01-01

    We report a molecular modeling study, coupled with spectroscopy experiments, on the behavior of two well known organic dyes, nile blue and nile red, when interacting with B-DNA. In particular, we evidence the presence of two competitive binding modes, for both drugs. However their subsequent photophysical behavior is different and only nile blue is able to induce DNA photosensitization via an electron transfer mechanism. Most notably, even in the case of nile blue, its sensitization capabilities strongly depend on the environment resulting in a single active binding mode: the minor groove. Fluorescence spectroscopy confirms the presence of competitive interaction modes for both sensitizers, while the sensitization via electron transfer, is possible only in the case of nile blue. PMID:27329409

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

    NASA Astrophysics Data System (ADS)

    Worqlul, A. W.; Collick, A. S.; Tilahun, S. A.; Langan, S.; Rientjes, T. H. M.; Steenhuis, T. S.

    2015-02-01

    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.

  16. Ultrashort Dephasing Time Measurements in Nile Blue Polymer Films

    NASA Astrophysics Data System (ADS)

    Schwendiman, Julie J.; Grossman, Carl

    1998-03-01

    Ultrafast optical dephasing measurements were performed on thin films of the oxazine dye Nile Blue in poly-[vinyl alcohol] (PVOH). The experimental technique used two beam, time delayed degenerate four wave mixing (DFWM) with incoherent light.(T. Kobayashi, A. Terasaki, T. Hattori and K. Kurokawa, Appl. Phys. B 47, 107 (1988).) Under the conditions that the sample was at relatively high temperatures (between 200=B0K and room temperature) and the measurements were made on the blue side of the Nile Blue inhomogeneous distribution, small time delay oscillations in the were observed. A time delay period was measured at 1.96 +/- .07 fs, which corresponds to the central period of the incoherent light source (centered at 575 nm with a period of 1.92 fs). A comparison between the measured oscillation depth and a numerical simulation of the DFWM scattered intensity yields an estimate of a phase relaxation time between 2 and 3 femtoseconds. This technique offers a new method of measuring femtosecond dephasing times with applications to samples of broad homogeneous linewidths, at high temperatures or in highly interacting environments. The depth of the oscillation decreased with lower temperature and completely disappeared below T=3D100=B0K. The temperature dependence of this effect is currently under investigation.

  17. Laser output of nile blue A sulfate-xanthene in ethyl alcohol under coaxial flashlamp pumping*

    SciTech Connect

    Zhang Fugeng; Yu Chunlian

    1988-03-01

    Experimental results of laser output of nile blue A sulfate-xanthene in ethyl alcohol under coaxial flashlamp pumping are reported. Owing to the sensitization effect of rhodamine 6G the laser conversion efficiency of nile blue sulfate has been increased by 80%.

  18. Modeling the hydrologic effects of land and water development interventions: a case study of the upper Blue Nile river basin

    NASA Astrophysics Data System (ADS)

    Haregeweyn, Nigussie; Tsunekawa, Atsushi; Tsubo, Mitsuru; Meshesha, Derege; Adgo, Enyew; Poesen, Jean; Schütt, Brigitta

    2014-05-01

    Over 67% of the Ethiopian landmass has been identified as very vulnerable to climate variability and land degradation. These problems are more prevalent in the Upper Blue Nile (UBN, often called Abay) river basin covering a drainage area of about 199,800 km2. The UBN River runs from Lake Tana (NW Ethiopia) to the Ethiopia-Sudan border. To enhance the adaptive capacity to the high climate variability and land degradation in the basin, different land and water management measures (stone/soil bunds, runoff collector trenches, exclosures) have been extensively implemented, especially since recent years. Moreover, multipurpose water harvesting schemes including the Grand Ethiopian Renaissance Dam (GERD, reservoir area of ca. 4000 km2) and 17 other similar projects are being or to be implemented by 2025. However, impact studies on land and water management aspects rarely include detailed hydrological components especially at river basin scale, although it is generally regarded as a major determinant of hydrological processes. The main aim of this study is therefore to model the significance of land and water management interventions in surface runoff response at scale of UBN river basin and to suggest some recommendations. Spatially-distributed annual surface runoff was simulated for both present-day and future (2025) land and water management conditions using calibrated values of the proportional loss model in ArcGIS environment. Average annual rainfall map (1998-2012) was produced from calibrated TRMM satellite source and shows high spatial variability of rainfall ranging between ca. 1000 mm in the Eastern part of the basin to ca. 2000 mm in the southern part of the basin. Present-day land use day condition was obtained from Abay Basin Master Plan study. The future land use map was created taking into account the land and water development interventions to be implemented by 2025. Under present-day conditions, high spatial variability of annual runoff depth was observed

  19. Scanning Electrochemical Microscopy of DNA Monolayers Modified with Nile Blue

    PubMed Central

    Gorodetsky, Alon A.; Hammond, William J.; Hill, Michael G.; Slowinski, Krzysztof; Barton, Jacqueline K.

    2009-01-01

    Scanning electrochemical microscopy (SECM) is used to probe long-range charge transport (CT) through DNA monolayers containing the redox-active Nile Blue (NB) intercalator covalently affixed at a specific location in the DNA film. At substrate potentials negative of the formal potential of covalently attached NB, the electrocatalytic reduction of Fe(CN)63− generated at the SECM tip is observed only when NB is located at the DNA/solution interface; for DNA films containing NB in close proximity to the DNA/electrode interface, the electrocatalytic effect is absent. This behavior is consistent with both rapid DNA-mediated CT between the NB intercalator and the gold electrode as well as a rate-limiting electron transfer between NB and the solution phase Fe(CN)63−. The DNA-mediated nature of the catalytic cycle is confirmed through sequence-specific and localized detection of attomoles of TATA-binding protein, a transcription factor that severely distorts DNA upon binding. Importantly, the strategy outlined here is general and allows for the local investigation of the surface characteristics of DNA monolayers both in the absence and in the presence of DNA binding proteins. These experiments highlight the utility of DNA-modified electrodes as versatile platforms for SECM detection schemes that take advantage of CT mediated by the DNA base pair stack. PMID:19053641

  20. Age and origin of the Gezira alluvial fan between the Blue and White Nile rivers

    NASA Astrophysics Data System (ADS)

    Williams, martin

    2014-05-01

    The Gezira is a low-angle alluvial fan bounded by the Blue Nile to the east and the White Nile to the west. It is the main agricultural region of Sudan and produces high quality long-staple cotton for export. Dark cracking clays (vertisols) cover much of the Gezira and range in age from 50 kyr to Holocene. The Gezira is traversed by a series of defunct sandy channels that originate between Sennar and Wad Medani on the present-day Blue Nile. With a radius of 300 km and an area of 40,000 km2 the Gezira is a mega-fan. The younger channels range in age from early Holocene to 100 kyr, while near surface channels filled with rolled quartz and carbonate gravels have ages back to >250 kyr. Boreholes in the Gezira reveal coarse alluvial sands and gravels in now buried channels overlain by alluvial clays, forming a repetitive sequence of fining-upwards alluvial units. that probably extend back to Pliocene times. The fan is up to 180 m thick with a volume of ~1,800 km3. The sandy or gravelly bed-load channels coincide with colder drier climates and sparse vegetation in the Ethiopian headwaters of the Blue Nile and the alluvial clays denote widespread flooding during times of stronger summer monsoon. The early stages of such flood events were often accompanied by mass burial of Nile oyster (Etheria elliptica) beds, such as the 45-50 kyr floods that deposited up to 5 m of clay in the northern Gezira. A unique feature of the eastern Gezira is a former Blue Nile channel at least 80 km long running parallel to the present river and entirely filled with volcanic ash. The channel was only 3-4 m deep and 20-30 m wide. Very fine laminations and cross-beds, together with locally abundant phytoliths and sponge spicules, suggest slow-moving water, with flow dispersed across many distributary channels. The ash geochemistry is similar to that in the lower part of the Kibish Formation in the lower Omo valley of southern Ethiopia and points to a minimum age of 100 kyr and a maximum age of

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  2. 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

    NASA Astrophysics Data System (ADS)

    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.

  3. Hydrological Response to Climate Change over the Blue Nile Basin Distributed hydrological modeling based on surrogate climate change scenarios

    NASA Astrophysics Data System (ADS)

    Berhane, F. G.; Anyah, R. O.

    2010-12-01

    The program Soil and Water Assessment Tool (SWAT2009) model has been applied to the Blue Nile Basin to study the hydrological response to surrogate climate changes over the Blue Nile Basin (Ethiopia) by downscaling gridded weather data. The specific objectives of the study include (i) examining the performance of the SWAT model in simulating hydrology-climate interactions and feedbacks within the entire Blue Nile Basin, and (ii) investigating the response of hydrological variables to surrogate climate changes. Monthly weather data from the Climate Research Unit (CRU) are converted to daily values as input into the SWAT using Monthly to Daily Weather Converter (MODAWEC). Using the program SUFI-2 (Sequential Uncertainty Fitting Algorithm), data from 1979 to 1983 are applied for sensitivity analysis and calibration (P-factor = 90%, R-factor =0.7, R2 =0.93 and NS=0.93) and subsequently to validate hindcasts over the period 1984-1989 (R2 =0.92 and NS=0.92). The period from 1960-2000 was used as baseline and has been used to determine the changes and the effect of the surrogate climate changes over the Blue Nile Basin. Overall, our surrogate climate change based simulations indicate the hydrology of the Blue Nile catchment is very sensitive to potential climate change with 100%, 34% and 51% increase to the surface runoff, lateral flow and water yield respectively for the A2 scenario surrogate. Key Words: SWAT, MODAWEC, Blue Nile Basin, SUFI-2, climate change, hydrological modeling, CRU

  4. Prediction of future climate change for the Blue Nile, using a nested Regional Climate Model

    NASA Astrophysics Data System (ADS)

    Soliman, E.; Jeuland, M.

    2009-04-01

    Although the Nile River Basin is rich in natural resources, it faces many challenges. Rainfall is highly variable across the region, on both seasonal and inter-annual scales. This variability makes the region vulnerable to droughts and floods. Many development projects involving Nile waters are currently underway, or being studied. These projects will lead to land-use patterns changes and water distribution and availability. It is thus important to assess the effects of a) these projects and b) evolving water resource management and policies, on regional hydrological processes. This paper seeks to establish a basis for evaluation of such impacts within the Blue Nile River sub-basin, using the RegCM3 Regional Climate Model to simulate interactions between the land surface and climatic processes. We first present results from application of this RCM model nested with downscaled outputs obtained from the ECHAM5/MPI-OM1 transient simulations for the 20th Century. We then investigate changes associated with mid-21st century emissions forcing of the SRES A1B scenario. The results obtained from the climate model are then fed as inputs to the Nile Forecast System (NFS), a hydrologic distributed rainfall runoff model of the Nile Basin, The interaction between climatic and hydrological processes on the land surface has been fully coupled. Rainfall patterns and evaporation rates have been generated using RegCM3, and the resulting runoff and Blue Nile streamflow patterns have been simulated using the NFS. This paper compares the results obtained from the RegCM3 climate model with observational datasets for precipitation and temperature from the Climate Research Unit (UK) and the NASA Goddard Space Flight Center GPCP (USA) for 1985-2000. The validity of the streamflow predictions from the NFS is assessed using historical gauge records. Finally, we present results from modeling of the A1B emissions scenario of the IPCC for the years 2034-2055. Our results indicate that future

  5. Prediction of future climate change for the Blue Nile, using RCM nested in GCM

    NASA Astrophysics Data System (ADS)

    Sayed, E.; Jeuland, M.; Aty, M.

    2009-04-01

    Although the Nile River Basin is rich in natural resources, it faces many challenges. Rainfall is highly variable across the region, on both seasonal and inter-annual scales. This variability makes the region vulnerable to droughts and floods. Many development projects involving Nile waters are currently underway, or being studied. These projects will lead to land-use patterns changes and water distribution and availability. It is thus important to assess the effects of a) these projects and b) evolving water resource management and policies, on regional hydrological processes. This paper seeks to establish a basis for evaluation of such impacts within the Blue Nile River sub-basin, using the RegCM3 Regional Climate Model to simulate interactions between the land surface and climatic processes. We first present results from application of this RCM model nested with downscaled outputs obtained from the ECHAM5/MPI-OM1 transient simulations for the 20th Century. We then investigate changes associated with mid-21st century emissions forcing of the SRES A1B scenario. The results obtained from the climate model are then fed as inputs to the Nile Forecast System (NFS), a hydrologic distributed rainfall runoff model of the Nile Basin, The interaction between climatic and hydrological processes on the land surface has been fully coupled. Rainfall patterns and evaporation rates have been generated using RegCM3, and the resulting runoff and Blue Nile streamflow patterns have been simulated using the NFS. This paper compares the results obtained from the RegCM3 climate model with observational datasets for precipitation and temperature from the Climate Research Unit (UK) and the NASA Goddard Space Flight Center GPCP (USA) for 1985-2000. The validity of the streamflow predictions from the NFS is assessed using historical gauge records. Finally, we present results from modeling of the A1B emissions scenario of the IPCC for the years 2034-2055. Our results indicate that future

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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

  8. Late Pleistocene and Holocene drought events at Lake Tana, the source of the Blue Nile

    NASA Astrophysics Data System (ADS)

    Marshall, Michael H.; Lamb, Henry F.; Huws, Dei; Davies, Sarah J.; Bates, Richard; Bloemendal, Jan; Boyle, John; Leng, Melanie J.; Umer, Mohammed; Bryant, Charlotte

    2011-08-01

    Magnetic and geochemical core data spanning the last 17,000 years are correlated with new seismic stratigraphy from Lake Tana, Ethiopia, to infer past lake-level change and hence effective precipitation. The data confirm that low lake-level coincides with Heinrich Event 1 (H1) in the North Atlantic, as previously shown from diatom and pollen evidence (Lamb et al., 2007). The lake deepened at 15.3 cal kyr BP and abruptly returned to freshwater conditions, when the lake overflowed into the Blue Nile. Low runoff and lake levels and therefore rainfall are inferred between 13.0 and 12.5 cal kyr BP and may represent southerly suppression of the ITCZ and the associated monsoon front at the time of the Younger Dryas. Two drought episodes occurred at 8.4 and 7.5 cal kyr BP, and are also interpreted as a southward shift in the monsoon front. The first of these events appears to have preceded and been more significant than the 8.2 cal kyr BP. Precipitation declined after 6.8 cal kyr BP, although we do not see an abrupt end to the African Humid Period. This period culminated in a dry episode at ~ 4.2 cal kyr BP, supporting the view that reduced Nile flow was a contributing factor to the demise of the Egyptian Old Kingdom.

  9. Investigation of Regional Drivers for Discharge Variability in the Blue Nile Basin under Climate Change Conditions

    NASA Astrophysics Data System (ADS)

    Tecklenburg, J.; Hattermann, F. F.; Liersch, S.

    2012-04-01

    A discharge time series is the result of complex and interacting processes. Important for the runoff variability are catchment characteristics like the basin size and shape, gradient of altitude and exposition as well as micro- and macroclimatic conditions. The discharge dynamic of the Blue Nile is predominantly controlled by the monsoon variability. Due to the steep gradients in the Ethiopian highlands, the surface flow component represents the main fraction of the total discharge. The composition of discharge and the resulting time response of river runoff is further a function of subsurface retention and surface roughness. Thus, the soil surface characteristics and thereby the land use are main factors controlling formation of local water availability in the Upper Blue Nile basin. During the last 30 years the continual transformation of forest and grassland to cropland reduced the total forest area of Ethiopia to 2.5 % with respect to the total area. Regarding the discharge formation process, land cover change supports generation of surface flow because of degradation of the surface roughness with two mainly negative effects: more surface runoff and less vegetation cover leads to erosion and degradation of soils. On the other hand, the water available for plants (soil moisture) may be reduced by a decreasing infiltration rate. Both effects have consequences for agricultural production and lead to an increasing demand for irrigation. Thus, the combination of the processes may accelerate the negative environmental response which makes the system highly vulnerable and sensitive to changes in driving forces. This study aims at analyzing the correlation of possible regional drivers with the inter-seasonal and inter-annual variability of subcatchment discharge generation. The study will be carried out applying the eco-hydrological model SWIM (Soil and Water Integrated Model) driven by observed and scenario climate data. Based on satellite image information the effect

  10. Preconcentration and separation of iron, zinc, cadmium and mercury, from waste water using Nile blue a grafted polyurethane foam.

    PubMed

    El-shahat, M F; Moawed, E A; Zaid, M A A

    2003-04-10

    The present work describes a novel method for the incorporation of Nile blue A into polyurethane foam matrix. This foam material was found to be very suitable for the extraction of metal ions from aqueous solutions. The characterization of Nile blue A grafted foam and the effect of halide concentration, pH, shaking time, extraction isotherm and capacity have been investigated. This foam material was found to be suitable for the separation and preconcentration of iron (III), zinc (II), cadmium (II) and mercury (II) from waste water. The extraction was accomplished in (15-20) minutes. Iron was separated from acid medium (2-4 M HCl), zinc from (3-5 M HCl), cadmium from (4-6 M HCl) as thiocyanate complexes and mercury was separated from (1-2 M HCl) as chloride. PMID:18968973

  11. Effects of Bahir Dar Textile Factory Effluents on the Water Quality of the Head Waters of Blue Nile River, Ethiopia

    PubMed Central

    Mehari, Abrehet Kahsay; Gebremedhin, Shewit; Ayele, Belayneh

    2015-01-01

    The study was conducted in 2013/14 with the objective of determining the effects of Bahir Dar textile factory effluents on the head of Blue Nile River water quality. Dissolve oxygen was higher at the upstream site of the river, whereas BOD5, TDS, and total alkalinity values were higher at wastewater outlet of the factory site. The mean values of dissolved oxygen, BOD5, and total alkalinity were above maximum permissible limits set by WHO for drinking water at head of Blue Nile River. The mean value of BOD5 was above permissible limit of IFC for textile effluents to be discharged to surface water. A total of 836 aquatic macroinvertebrate individuals belonging to 21 families were collected. The Shannon-Wiener Diversity Index, the Hilsenhoff family-level biotic index, family richness, and percent dipterans were calculated. Hilsenhoff family-level biotic index and percent dipterans metrics differed significantly among sampling sites (P < 0.05). Hilsenhoff family-level biotic index was higher at the most downstream site but percent dipterans were higher at site of discharge of effluent to the head of Blue Nile River. Therefore, there is indication that effluent demands frequent control and proper treatment before being discharged to the environment. PMID:26688685

  12. Permian and Triassic microfloral assemblages from the Blue Nile Basin, central Ethiopia

    NASA Astrophysics Data System (ADS)

    Dawit, Enkurie L.

    2014-11-01

    Palynological investigation was carried out on surface samples from up to 400 m thick continental siliciclastic sediments, here referred to as “Fincha Sandstone”, in the Blue Nile Basin, central Ethiopia. One hundred sixty species were identified from 15 productive samples collected along a continuous road-cut exposure. Six informal palynological assemblage zones have been identified. These assemblage zones, in ascending order, are: “Central Ethiopian Permian Assemblage Zone - CEPAZ I”, earliest Permian (Asselian-Sakmarian); “CEPAZ II”, late Early Permian (Artinskian-Kungurian); CEPAZ III - Late Permian (Kazanian-Tatarian); “CETAZ IV”, Lower Triassic (Olenekian Induan); “CETAZ V”, Middle Triassic (Anisian Ladinian); “CETAZ VI”, Late Triassic (Carnian Norian). Tentative age ranges proposed herein are compared with faunally calibrated palynological zones in Gondwana. The overall composition and vertical distribution of miospores throughout the studied section reveals a wide variation both qualitatively and quantitatively. The high frequency of monosaccate pollen in CEPAZ I may reflect a Glossopterid-dominated upland flora in the earliest Permian. The succeeding zone is dominated by straite/taeniate disaccate pollen and polyplicates, suggesting a notable increase in diversity of glossopterids. The decline in the diversity of taeniate disaccate pollen and the concomitant rise in abundance of non-taeniate disaccates in CEPAZ III may suggest the decline in Glossopteris diversity, though no additional evidence is available to equate this change with End-Permian extinction. More diverse and dominant non-taeniate, disaccate, seed fern pollen assignable to FalcisporitesAlisporites in CETAZ IV may represent an earliest Triassic recovery flora. The introduction of new disaccate forms with thick, rigid sacci, such as Staurosaccites and Cuneatisporites, in CETAZ V and VI may indicate the emergence of new gymnospermous plants that might have favourably

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

    NASA Astrophysics Data System (ADS)

    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

  14. Rain event properties and dimensionless rain event hyetographs at the source of the Blue Nile River

    NASA Astrophysics Data System (ADS)

    Haile, A. T.; Rientjes, T.; Habib, E.; Jetten, V.

    2010-08-01

    In the present study, the spatial and temporal patterns of the rain event properties are analysed. The event properties are rain event depth, event duration, mean event intensity, peak intensity and the time span between two consecutive rain events which is referred to as inter-event time (IET). Dimensionless event hyetographs are established by relating fractions of event intensities to the corresponding fractions of event durations. The spatial variation of the characteristics of the hyetographs is also evaluated. A model in the form of the beta distribution function is applied to reproduce the dimensionless hyetographs. Rainfall data is obtained from a field campaign in two wet seasons of June-August (JJA) of 2007 and 2008 in the Gilgel Abbay watershed that is situated at the source basin of the upper Blue Nile River in Ethiopia. The rainfall data was recorded at eight stations. The results reveal that rain event depth is more related to peak intensity than to event duration. At the start and towards the end of the wet season, the rain events have larger depth with longer duration and longer IET than the rain events in the mid-season. Mean event intensity and IET are strongly related to terrain elevation. Sekela which is on a mountain area has the shortest IET while Bahir Dar which is at the south shore of the lake has the longest IET.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    Erkossa, T.; Wudneh, A.; Desalegn, B.; Taye, G.

    2015-02-01

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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 <5 mm, or daily accumulations of <10 mm, and the uncertainty values decrease with increasing rainfall accumulation. Among the satellite products, CMORPH suffers from a large positive bias at the lowland plain site, and TMPA-RP and TMPA-RT miss a large number of rainfall events that contribute nearly half of the total rainfall at the highland mountain.

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

    NASA Astrophysics Data System (ADS)

    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.

  20. Electrochemical properties of interstrand cross-linked DNA duplexes labeled with Nile blue.

    PubMed

    Mie, Yasuhiro; Kowata, Keiko; Kojima, Naoshi; Komatsu, Yasuo

    2012-12-11

    DNA molecules have attracted considerable attention as functional materials in various fields such as electrochemical sensors with redox-labeled DNA. However, the recently developed interstrand cross-link (ICL) technique for double-stranded DNA can adequately modify the electronic properties inside the duplex. Hence, the electrochemical investigation of ICL-DNA helps us to understand the electron transfer of redox-labeled DNA at an electrode surface, which would develop useful sensors. In this study, the first insight into this matter is presented. We prepared 17-mer DNA duplexes incorporating Nile blue (NB-DNA) at one end as a redox marker and a disulfide tether at the other end for immobilization onto an electrode. The duplexes were covalently cross-linked by bifunctional cross-linkers that utilize either a propyl or naphthalene residue to replace a base pair. Their electrochemical responses at the electrode surface were compared to evaluate the effect of the ICL on the electron-transfer reactions of the redox-labeled DNA duplexes. A direct transfer of electrons between NB and the electrode was observed for a standard DNA, as previously reported, whereas interstrand cross-linked DNA (CL-DNA) strands showed a decrease in the direct electron-transfer pathway. This is expected to result from constraining the elastic bending/flexibility of the duplex caused by the covalent cross-links. Interestingly, the CL-DNA incorporating naphthalene residues exhibited additional voltammetric peaks derived from DNA-mediated electron transfer (through base π stacking), which was not observed in the mismatched CL-DNA. The present results indicate that the ICL significantly affects electron transfer in the redox-labeled DNA at the electrode and can be an important determinant for electrochemical signaling in addition to its role in stabilizing the duplex structure. PMID:23153070

  1. Spectral Inspections on Molecular Configurations of Nile Blue A Adsorbed on the Elementary Clay Sheets.

    PubMed

    Huang, Mei; He, Shuai; Liu, Wenhong; Yao, Yunjin; Miao, Shiding

    2015-10-22

    Studies on the configuration of dye molecules are of great importance in revealing origins of the electronic bands as well as understanding their transitions. In this work, we utilized dye molecules named Nile blue A, which are a type of oxazine dyes, to study the molecular configurations when they are transferred from solutions to a solid surface. The Langmuir-Blodgett (LB) technique was employed to construct such an interface where the interaction between the dye molecules and solid supports can be pursued. Hybrid films were prepared via the LB depositions, and the dye molecules were assembled on the elementary clay sheets (laponite, saponite). The configuration of Nb reflected by the molecular orientation, packing density, phase behavior, and variances of the surface tension has been derived. The ex situ spectroscopy characterizations such as UV-vis absorption, fluorescence emission, and excitation spectra were carried out on these LB films to reveal the fact that the adsorbed Nb molecules are mainly assembled in two types of configurations. Adsorbed state I was found to be achieved at high concentrations (1-10 ppm) of clay dispersions and low surface pressure (∼5 mN/m). In this state the anionic oxazine rings of Nb are adsorbed on clay sheets sharing a large lift-off area. This configuration gives allowable fluorescence (λ = 550 nm). Lower clay concentration (<1 ppm) and high surface pressure (10-30 mN/m) yield the adsorbed state II in which the oxazine chromophores were arranged in a side-by-side style, and the dye molecules stand perpendicularly to the clay sheets. This conformation exhibits no photoluminescence. PMID:26436823

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

    NASA Astrophysics Data System (ADS)

    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

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

    NASA Astrophysics Data System (ADS)

    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

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

    NASA Astrophysics Data System (ADS)

    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.

  5. Morpho-tectonic analysis of the Tekeze River and the Blue Nile drainage systems on the Northwestern Plateau, Ethiopia

    NASA Astrophysics Data System (ADS)

    Ismail, Elamin H.; Abdelsalam, Mohamed G.

    2012-07-01

    This study examines the morpho-tectonic evolution of the drainage system in the Northwestern Plateau in Ethiopia dominated by the Tekeze River and the Blue Nile. The Northwestern Plateau is underlain by Precambrian crystalline rocks, followed by Mesozoic sedimentary section and topped with Oligocene-Quaternary volcanic rocks. The plateau is bounded in the east and southeast by the Afar Depression and the Main Ethiopian Rift, respectively. Digital Elevation Models (DEMs) from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and the Shuttle Radar Topography Mission (SRTM) data are analyzed to extract morpho-tectonic parameters including the Normalized Steepness Index (Ksn), the Concavity (θ) and the Regression Fit (r2) between the observed and predicted channel profiles from the sub-basins and the tributaries of the Tekeze River and the Blue Nile. Analysis of these morpho-tectonic parameters has shown that the evolution of the drainage systems on the Northwestern Plateau was influenced by three tectonic and geological events. The first event resulted in a broad and regional uplift of the plateau, most likely due to the rise of the Afar mantle plume ˜30 Ma. This regional uplift was accompanied by moderate incision rate of the Tekeze River and the Blue Nile drainage systems within the entire Northwestern Plateau. The second event, which was in the form of shield volcanoes build-up, occurred at ˜22 Ma and resulted in localized increase in the incision rate around these volcanoes. The third event is manifested by rift-flank uplift at ˜11 Ma on the western escarpments of the Afar Depression and the northwestern escarpments of the Main Ethiopian Rift. This event resulted in an increase in the incision rate of the Tekeze River and the Blue Nile drainage systems, but this increase seems to diminish towards the west and northwest leaving the drainage systems in the lower reaches of the two rivers relatively tectonically undisturbed, hence

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

    NASA Astrophysics Data System (ADS)

    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.

  7. Nile Blue-Based Nanosized pH Sensors for Simultaneous Far-Red and Near-Infrared Live Bioimaging

    PubMed Central

    2013-01-01

    Diblock copolymer vesicles are tagged with pH-responsive Nile Blue-based labels and used as a new type of pH-responsive colorimetric/fluorescent biosensor for far-red and near-infrared imaging of live cells. The diblock copolymer vesicles described herein are based on poly(2-(methacryloyloxy)ethyl phosphorylcholine-block-2-(diisopropylamino)ethyl methacrylate) [PMPC-PDPA]: the biomimetic PMPC block is known to facilitate rapid cell uptake for a wide range of cell lines, while the PDPA block constitutes the pH-responsive component that enables facile vesicle self-assembly in aqueous solution. These biocompatible vesicles can be utilized to detect interstitial hypoxic/acidic regions in a tumor model via a pH-dependent colorimetric shift. In addition, they are also useful for selective intracellular staining of lysosomes and early endosomes via subtle changes in fluorescence emission. Such nanoparticles combine efficient cellular uptake with a pH-responsive Nile Blue dye label to produce a highly versatile dual capability probe. This is in marked contrast to small molecule dyes, which are usually poorly uptaken by cells, frequently exhibit cytotoxicity, and are characterized by intracellular distributions invariably dictated by their hydrophilic/hydrophobic balance. PMID:24001153

  8. Nile Blue-based nanosized pH sensors for simultaneous far-red and near-infrared live bioimaging.

    PubMed

    Madsen, Jeppe; Canton, Irene; Warren, Nicholas J; Themistou, Efrosyni; Blanazs, Adam; Ustbas, Burcin; Tian, Xiaohe; Pearson, Russell; Battaglia, Giuseppe; Lewis, Andrew L; Armes, Steven P

    2013-10-01

    Diblock copolymer vesicles are tagged with pH-responsive Nile Blue-based labels and used as a new type of pH-responsive colorimetric/fluorescent biosensor for far-red and near-infrared imaging of live cells. The diblock copolymer vesicles described herein are based on poly(2-(methacryloyloxy)ethyl phosphorylcholine-block-2-(diisopropylamino)ethyl methacrylate) [PMPC-PDPA]: the biomimetic PMPC block is known to facilitate rapid cell uptake for a wide range of cell lines, while the PDPA block constitutes the pH-responsive component that enables facile vesicle self-assembly in aqueous solution. These biocompatible vesicles can be utilized to detect interstitial hypoxic/acidic regions in a tumor model via a pH-dependent colorimetric shift. In addition, they are also useful for selective intracellular staining of lysosomes and early endosomes via subtle changes in fluorescence emission. Such nanoparticles combine efficient cellular uptake with a pH-responsive Nile Blue dye label to produce a highly versatile dual capability probe. This is in marked contrast to small molecule dyes, which are usually poorly uptaken by cells, frequently exhibit cytotoxicity, and are characterized by intracellular distributions invariably dictated by their hydrophilic/hydrophobic balance. PMID:24001153

  9. Unforeseen distance-dependent SERS spectroelectrochemistry from surface-tethered Nile Blue: the role of molecular orientation.

    PubMed

    Wilson, Andrew J; Willets, Katherine A

    2016-08-15

    Covalent immobilization of redox-active dyes is an important strategy to evaluate structure-activity relationships in nanoscale electrochemistry by using optical readouts such as surface-enhanced Raman scattering (SERS). Here we investigate the role of the tether length in the SERS spectroelectrochemistry of surface-attached Nile Blue. Differential pulse voltammetry and a potential-dependent SERS derivative analysis reveal that the Nile Blue molecules adopt a different orientation with respect to the electrode surface as the number of carbons in a carboxylic acid-terminated alkanethiol monolayer is varied, which leads to unique SERS spectroelectrochemical behaviors. We use the relative molecular orientations and spectral characteristics to propose a model in which tethers shorter than the length of the molecule limit molecular motion under electrochemical perturbation, but tethers longer than the length of the molecule allow dye intercalation into the hydrophobic self-assembled monolayer, producing an unexpected decrease in the SERS intensity when the molecule is in the oxidized form. PMID:27337143

  10. Fluorescence-line-narrowing spectroscopy of nile blue in glass and polymer at 5 K: Determination of a single-site line shape function

    NASA Astrophysics Data System (ADS)

    Zhang, Yiping; Hartmann, S. R.; Moshary, F.

    1996-03-01

    Fluorescence-line-narrowing (FLN) spectra of the oxazine dye nile blue are obtained at 5 K in both ethanol glass and PVOH polymer. Multiple spectra, each associated with a different excitation wavelength setting, are presented. We analyze these spectra assuming a site-independent molecular response. Excellent agreement obtains in the ethanol glass host.

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

    NASA Astrophysics Data System (ADS)

    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 (<40 microns and 125-180 microns) of 30 samples, and systematic changes related to grain size and hydraulic-sorting processes could thus be investigated. On the same samples, companion studies are being carried out on Sr isotopes (Padoan et al., 2007) and on Pb isotopes at the Geological Survey of Israel (Harlavan et al., in preparation). Overall, isotopic signals are markedly different between the White Nile system, derived from largely Archean to Paleoproterozoic basement rocks, and Ethiopian tributaries, derived in diverse proportions from largely Neoproterozoic rift-shoulder basements and overlying Oligocene flood basalts. Isotopic signals of Main Nile sediments downstream of the Atbara confluence are close to those of Blue Nile sediments, indicating that detritus is mainly provided by the latter (Garzanti et al., 2006). In the White Nile branch, the 143Nd/144Nd ratio of the mud fraction is lower in the Bahr Ez Zeraf (0.51167) than in the White Nile downstrean of the Sobat confluence (0.51219), revealing significant sediment influx from the latter. In Blue Nile and Atbara branches

  12. Assessment of Active Landslides in Sanbaro Sago Valley, Blue-Nile Catchment, Ethiopia

    NASA Astrophysics Data System (ADS)

    Hailemariam Gugsa, Trufat

    2010-05-01

    In fall of 2009, a detail field mapping was carried out in the Sanbaro Sago Valley, south-eastern of Blue-Nile catchment, to inspect the landslide processes that affected the livelihood of more than 6,000 peoples. The valley is a part of Ethiopian highlands where long histories of rainfall triggered landslides are prominent. The villagers suffered the recurring landslides for the last five years, even at present; there are numerous evidences of active landslides, with some actual slides currently taking place. The nature their activity indicate high probability of destructive phenomena within the foreseeable future. The landslides already damaged houses, farm plots and drainage ditch, as well; more than 40 causalities are recorded. Most of the dwellers have been permanently displaced from their residences, as they lost their houses and farm plots. A preliminary zoning was made through the interpretation of satellite images (+ETM Land sat) that drape over the digital elevation model of the area, which followed by detail field investigation to map the geological, geomorphological, and anthropogenic factors that contribute to the landslide activity. The valley consists of low lying graben bounded by steep scarps that characterized by highly weathered Tertiary basaltic rocks covered with Quaternary deposits. Structurally controlled, alluvial and denudational landforms are present. There are distinct geomorphic units formed by differences in the lithology of the various basalt types. The Quaternary deposits along the ridge that has many rills and incised gullies are characterized by weathered basalts and alluvial-colluvial deposits. The elevation of the valley ranges from 1290m to 3200m m.a.s.l. The steep slopes, volcanic hills, exposed on the downthrown side of the major scarps have been modified by erosion, resulting in a highly dissected topography with steep gullies. This makes the steep slopes of the ridge to be one of landslide prone areas. Many of the active

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

    PubMed

    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. PMID:18930436

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

    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

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

    NASA Astrophysics Data System (ADS)

    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.

  17. Patterns of West Nile virus infection in Ohio blue jays: implications for initiation of the annual cycle.

    PubMed

    Garvin, Mary C; Tarvin, Keith A; Smith, Jennifer; Ohajuruka, Ojimadu A; Grimes, Sheila

    2004-05-01

    West Nile virus (WNV) was first detected in North America in New York City in 1999 and rapidly moved westward. Understanding the mechanisms by which the amplification cycle is reinitiated each year increases our ability to predict epizootics and geographic expansion of the disease. Such understanding is enhanced by knowledge of the patterns of infection in the vertebrate reservoir hosts. Blue jays (Cyanocitta cristata) may serve as reservoir hosts for WNV. We examined the influence of age and date on the prevalence of WNV in jay carcasses in Ohio during May-August 2002. Percent of carcasses that were infected increased significantly with time from 3% in May to more than 90% by August. We found no difference in prevalence between juvenile (nestlings and fledglings) and adult jays early in the season, which contradicts the expected pattern if the majority of the adults sampled in 2002 had been exposed to the virus in 2001. Therefore, jays infected in 2001 were unlikely to have been important in initiating the 2002 virus cycle in Ohio. PMID:15155993

  18. Estimation of evaporation over the upper Blue Nile basin by combining observations from satellites and river flow gauges

    NASA Astrophysics Data System (ADS)

    Allam, Mariam M.; Jain Figueroa, Anjuli; McLaughlin, Dennis B.; Eltahir, Elfatih A. B.

    2016-02-01

    Reliable estimates of regional evapotranspiration are necessary to improve water resources management and planning. However, direct measurements of evaporation are expensive and difficult to obtain. Some of the difficulties are illustrated in a comparison of several satellite-based estimates of evapotranspiration for the Upper Blue Nile (UBN) basin in Ethiopia. These estimates disagree both temporally and spatially. All the available data products underestimate evapotranspiration leading to basin-scale mass balance errors on the order of 35 percent of the mean annual rainfall. This paper presents a methodology that combines satellite observations of rainfall, terrestrial water storage as well as river-flow gauge measurements to estimate actual evapotranspiration over the UBN basin. The estimates derived from these inputs are constrained using a one-layer soil water balance and routing model. Our results describe physically consistent long-term spatial and temporal distributions of key hydrologic variables, including rainfall, evapotranspiration, and river-flow. We estimate an annual evapotranspiration over the UBN basin of about 2.55 mm per day. Spatial and temporal evapotranspiration trends are revealed by dividing the basin into smaller subbasins. The methodology described here is applicable to other basins with limited observational coverage that are facing similar future challenges of water scarcity and climate change.

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

    NASA Astrophysics Data System (ADS)

    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%).

  20. Water Dynamics in Fogera and the Upper Blue Nile - Farmers perspectives and remote sensing

    NASA Astrophysics Data System (ADS)

    Chemin, Yann; Desalegn, Mengistu; Curnow, Jayne; Johnston, Robyn

    2015-04-01

    This research work is about finding the connection between farmers perspectives on changes of water conditions in their socio-agricultural environment and satellite remote sensing analysis. Key informant surveys were conducted to investigate localised views on water scarcity as a counterpoint to the physical measurement of water availability. Does a numerical or mapped image identifying water scarcity always equate to a dearth of water for agriculture? To push the limits of the relationship between human and physical data we sought to ground-truth GIS results with the practical experience and knowledge of people living in the area. We data-mined public domain satellite data with FOSS (GDAL, GRASS GIS) and produced water-related spatio-temporal domains for our study area and the larger Upper Nile Basin. Accumulated remote sensing information was then cross-referenced with informant's accounts of water availability for the same space and time. During the survey fieldwork the team also took photographs electronically stamped with GPS coordinates to compare and contrast the views of informants and the remote sensing information with high resolution images of the landscape. We found that farmers perspective on the Spring maize crop sensibility to variability of rainfall can be quantified in space and time by remote sensing cumulative transpiration. A crop transpiration gap of 1-2.5 mm/day for about 20 days is to be overcome, a full amount of 20 to 50 mm, depending on the type of year deficit. Such gap can be overcome, even by temporary supplemental irrigation practices, however, the economical and cultural set up is already developed in another way, as per sesonal renting of higher soil profile water retention capacity fields.

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

    NASA Astrophysics Data System (ADS)

    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.

  2. Influence of downscaling methods in projecting climate change impact on hydrological extremes of upper Blue Nile basin

    NASA Astrophysics Data System (ADS)

    Taye, M. T.; Willems, P.

    2013-06-01

    Methods from two statistical downscaling categories were used to investigate the impact of climate change on high rainfall and flow extremes of the upper Blue Nile basin. The main downscaling differences considered were on the rainfall variable while a generally similar method was applied for temperature. The applied downscaling methods are a stochastic weather generator, LARS-WG, and an advanced change factor method, the Quantile Perturbation Method (QPM). These were applied on 10 GCM runs and two emission scenarios (A1B and B1). The downscaled rainfall and evapotranspiration were input into a calibrated and validated lumped conceptual model. The future simulations were conducted for 2050s and 2090s horizon and were compared with 1980-2000 control period. From the results all downscaling methods agree in projecting increase in temperature for both periods. Nevertheless, the change signal on the rainfall was dependent on the climate model and the downscaling method applied. LARS weather generator was good for monthly statistics although caution has to be taken when it is applied for impact analysis dealing with extremes, as it showed a deviation from the extreme value distribution's tail shape. Contrary, the QPM method was good for extreme cases but only for good quality daily climate model data. The study showed the choice of downscaling method is an important factor to be considered and results based on one downscaling method may not give the full picture. Regardless, the projections on the extreme high flows and the mean main rainy season flow mostly showed a decreasing change signal for both periods. This is either by decreasing rainfall or increasing evapotranspiration depending on the downscaling method.

  3. Simulations of Water and Energy Cycles over the Congo and Upper Blue Nile basins by IPCC GCMs

    NASA Astrophysics Data System (ADS)

    Eltahir, E. A.; Siam, M.

    2012-12-01

    The simulations of the hydrological cycle in general circulation models (GCMs) are characterized by a significant degree of uncertainty. This uncertainty is reflected in the wide range of IPCC (Intergovernmental Panel on Climate Change) GCMs predictions of future changes in the hydrological cycle, particularly over major African basins. Here, we explore the relations between the surface radiation and hydrological cycle within 17 of the IPCC GCMs over the Congo and Upper Blue Nile (UBN) basins. Most GCMs overestimate the hydrological cycle over the basins compared to observations. This overestimation is associated with excess net surface radiation, attributed to an overestimation of downward shortwave radiation and an underestimation of upward longwave radiation at the surface compared to observations. In order to verify if the overestimation of the net radiation is a systematic problem in these models for other regions, the net surface radiation over the Sahara Desert is also investigated. Although the Sahara Desert has a different climatic conditions compared to the studied basins, but the persistent overestimation of the net surface radiation for all models over this region suggests that models tend to overestimate the net surface radiation at least over the majority of the African continent. Our results also show that the increase in horizontal resolution of GCMs results in a better simulations of the hydrological cycle. In addition, the absence of the radiation effects of mineral aerosols, biomass burning and low negative cloud feedback for most of the models can be responsible of the overestimation of both the energy and hydrological cycles over the studied regions.

  4. Linking soil erosion to on-site financial cost: lessons from watersheds in the Blue Nile basin

    NASA Astrophysics Data System (ADS)

    Erkossa, T.; Wudneh, A.; Desalegn, B.; Taye, G.

    2015-06-01

    The study was conducted in three watersheds (Dapo, Meja and Mizewa) in the Ethiopian part of the Blue Nile Basin to estimate the on-site 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 analysed. 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 N and P contents in runoff and sediment were determined. Crop response functions were developed for the two plant nutrients based on data obtained from the nearest Agricultural Research Centres. 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 USD 220 ha-1 and 150 ha-1 due to the loss of N and P, 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.

  5. Regional geomorphic analysis and gis susceptibility mapping of landslides in the blue nile and the tekeze river basins of ethiopia

    NASA Astrophysics Data System (ADS)

    Ismail, Elamin Hassan Dai

    The Plateau region of Ethiopia lies within a seismically active continental extensional regime, which is being rapidly incised by the Blue Nile and the Tekeze Rivers. Extremely large landslides pose serious hazards in this highly populated region (>27 million), which is in the process of developing its hydrologic resources. This research sought to develop cost-effective methods to compile regional landslide inventory and landslide susceptibility maps, using geomorphic tools and GIS technologies. This work also sought to evaluate the relationships between landslide dams and knickpoints, caused by channel bed incision from those caused by slope failures, by utilizing identified knickpoints along 56 tributary channels across the study area. The study employed the weighted overlay technique to produce regional landslide susceptibility hazard maps, and for the first time, employing wind-driven and integrated rainfall/aspect rasters at various inclination to more realistically model the actual precipitation that is felt by hillsides of varying azimuth, shape, and height. Landslides greater than 500m long were tentatively identified on 1:200,000 topographic maps draped over 30m hill-shade generated ASTER GDEMv2. The mapping revealed different types of landslides, and also revealed a considerable number of old, dormant landslide features. The use of wind-driven rainfall with integrated rainfall and aspect rasters provided a much more detailed and asymmetric distribution of precipitation. Spatial distribution of the very high and high hazard areas, during the Kermit and Belg rainy seasons by a range of 0.38% for an inclination of 40o and 1.7% for inclinations on 60o, as compared to the traditional assumption of 90o vertical rainfall, without integration of a slope aspect raster.

  6. Late Pleistocene and Holocene environments in the Nile basin

    NASA Astrophysics Data System (ADS)

    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.

  7. Error analysis of global satellite precipitation products using daily gauged observations over the upper central Blue Nile Basin

    NASA Astrophysics Data System (ADS)

    Sahlu, Dejene; Moges, Semu; Anagnostou, Emmanouil N.; Hailu, Dereje

    2015-04-01

    Water resource assessment, planning and management in Africa are often constrained due to lack of reliable spatio-temporal rainfall data. Satellite and global reanalysis products are steadily growing and offering useful alternative datasets of rainfall globally. Aim of this paper is to examine the error characteristics of the main available global satellite precipitation products with the view to improve the reliability of wet season (June to September) rainfall datasets over the upper Blue Nile Basin in Ethiopia. The study utilized six satellite derived precipitation datasets at 0.25-deg spatial grid size and daily temporal resolution:1) the near real-time (3B42_RT) and gauge adjusted (3B42_V7) products of Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA), 2) gauge adjusted and unadjusted Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks (PERSIANN) products and 3) the gauge adjusted and un-adjusted product of the National Oceanic and Atmospheric Administration (NOAA) Climate Prediction Center Morphing technique (CMORPH) over the period of 2000 to 2013. The historical daily rainfall data sets are chosen for the same period from 64 gauging stations which are within a mountainous area of about 45,000 km2. The elevation of gauges used in this error study ranged from 1800 to 3000 meters above sea level. The error analysis utilized statistical techniques of missed rainfall volume fraction (MRV), falsely detected rainfall volume fraction (FRV), mean relative error (MRE), bias ratio (Bias), coefficient of variation of error (CVE) and the trends of the error metrics with respect to elevation. The three error metrics, MRE, Bias and CVE are further examined for five rainfall thresholds associated with different percentile categories (2nd, 20th, 50th, 80th and 98th) . Results show that CMORPH has relatively lower MRV (~1.5 %) than the TRMM and PERSIANN products (10 -13 %.). Non-gauge adjusted

  8. Coupled hydrologic and land use change models for decision making on land and water resources in the Upper Blue Nile basin

    NASA Astrophysics Data System (ADS)

    Yalew, Seleshi; van der Zaag, Pieter; Mul, Marloes; Uhlenbrook, Stefan; Teferi, Ermias; van Griensven, Ann; van der Kwast, Johannes

    2013-04-01

    Hydrology of a basin, alongside climate change, is well documented to impact and to be impacted by land use/land cover change processes. The need to understand the impacts of hydrology on land use change and vice- versa cannot be overstated especially in basins such as the Upper Blue Nile in Ethiopia, where the vast majority of farmers depend on rain-fed agriculture. A slight fluctuation in rainy seasons or an increase or decrease in magnitude of precipitation can easily trigger drought or flooding. On the other hand, ever growing population and emerging economic development, among others, is likely to continually alter land use/land cover change, thereby affecting hydrological processes. With the intention of identifying and analyzing interactions and future scenarios of the hydrology and land use/land cover, we carried out a case study on a meso-scale catchment, in the Upper Blue Nile basin. A land use model using SITE (SImulation of Terrestrial Environments) was built for analyzing land use trends from aerial land cover photographs of 1957 and simulate until 2009 based on socio-economic as well as biophysical factors. Major land use drivers in the catchment were identified and used as input to the land use model. Separate land use maps were produced using Landsat images of 1972, 1986, 1994 and 2009 for historical calibration of the land use model. By the same token, a hydrological model for the same catchment was built using the SWAT (Soil and Water Assessment Tool) model. After calibration of the two independent models, they were loosely coupled for analyzing the changes in either of the models and impacts on the other. Among other details, the coupled model performed better in identifying limiting factors from both the hydrology as well as from the land use perspectives. For instance, the simulation of the uncoupled land use model alone (without inputs from SWAT on the water budget of each land use parcel) continually considered a land use type such as a wet

  9. Summer Rains and Dry Seasons in the Upper Blue Nile Basin: The Predictability of Half a Century of Past and Future Spatiotemporal Patterns

    PubMed Central

    Mellander, Per-Erik; Gebrehiwot, Solomon G.; Gärdenäs, Annemieke I.; Bewket, Woldeamlak; Bishop, Kevin

    2013-01-01

    During the last 100 years the Ethiopian upper Blue Nile Basin (BNB) has undergone major changes in land use, and is now potentially facing changes in climate. Rainfall over BNB supplies over two-thirds of the water to the Nile and supports a large local population living mainly on subsistence agriculture. Regional food security is sensitive to both the amount and timing of rain and is already an important political challenge that will be further complicated if scenarios of climate change are realized. In this study a simple spatial model of the timing and duration of summer rains (Kiremt) and dry season (Bega), and annual rain over the upper BNB was established from observed data between 1952 and 2004. The model was used to explore potential impacts of climate change on these rains, using a down-scaled ECHAM5/MP1-OM scenario between 2050 and 2100. Over the observed period the amount, onset and duration of Kiremt rains and rain-free Bega days have exhibited a consistent spatial pattern. The spatially averaged annual rainfall was 1490 mm of which 93% was Kiremt rain. The average Kiremt rain and number of rainy days was higher in the southwest (322 days) and decreased towards the north (136 days). Under the 2050–2100 scenario, the annual mean rainfall is predicted to increase by 6% and maintain the same spatial pattern as in the past. A larger change in annual rainfall is expected in the southwest (ca. +130 mm) with a gradually smaller change towards the north (ca. +70 mm). Results highlight the need to account for the characteristic spatiotemporal zonation when planning water management and climate adaptation within the upper BNB. The presented simple spatial resolved models of the presence of Kiremt and annual total rainfall could be used as a baseline for such long-term planning. PMID:23869219

  10. Summer rains and dry seasons in the upper Blue Nile Basin: the predictability of half a century of past and future spatiotemporal patterns.

    PubMed

    Mellander, Per-Erik; Gebrehiwot, Solomon G; Gärdenäs, Annemieke I; Bewket, Woldeamlak; Bishop, Kevin

    2013-01-01

    During the last 100 years the Ethiopian upper Blue Nile Basin (BNB) has undergone major changes in land use, and is now potentially facing changes in climate. Rainfall over BNB supplies over two-thirds of the water to the Nile and supports a large local population living mainly on subsistence agriculture. Regional food security is sensitive to both the amount and timing of rain and is already an important political challenge that will be further complicated if scenarios of climate change are realized. In this study a simple spatial model of the timing and duration of summer rains (Kiremt) and dry season (Bega), and annual rain over the upper BNB was established from observed data between 1952 and 2004. The model was used to explore potential impacts of climate change on these rains, using a down-scaled ECHAM5/MP1-OM scenario between 2050 and 2100. Over the observed period the amount, onset and duration of Kiremt rains and rain-free Bega days have exhibited a consistent spatial pattern. The spatially averaged annual rainfall was 1490 mm of which 93% was Kiremt rain. The average Kiremt rain and number of rainy days was higher in the southwest (322 days) and decreased towards the north (136 days). Under the 2050-2100 scenario, the annual mean rainfall is predicted to increase by 6% and maintain the same spatial pattern as in the past. A larger change in annual rainfall is expected in the southwest (ca. +130 mm) with a gradually smaller change towards the north (ca. +70 mm). Results highlight the need to account for the characteristic spatiotemporal zonation when planning water management and climate adaptation within the upper BNB. The presented simple spatial resolved models of the presence of Kiremt and annual total rainfall could be used as a baseline for such long-term planning. PMID:23869219

  11. Hydrogeological and hydrochemical framework of Upper Awash River basin, Ethiopia: With special emphasis on inter-basins groundwater transfer between Blue Nile and Awash Rivers

    NASA Astrophysics Data System (ADS)

    Yitbarek, Andarge; Razack, Moumtaz; Ayenew, Tenalem; Zemedagegnehu, Engida; Azagegn, Tilahun

    2012-04-01

    Integrated approach has been used to investigate the hydrogeological framework of a complex fractured volcanic aquifer system in the Upper Awash River basin located at the western shoulder of the Ethiopian Rift. The groundwater flow system and mechanism of recharge of different aquifers have been studied using conventional hydrogeological field investigations, hydrochemistry, and isotope hydrology. Litho-hydrostratigraphic relationships were constructed from lithologic logs obtained from exploratory drilling of deep boreholes. The result indicates quite complex flow pattern and hydraulic characteristics of the different volcanic aquifers. The litho-hydrostratigraphic correlation indicates that the permeable and porous scoraceous lower basaltic aquifer is extended laterally all the way from the Blue Nile Plateau to the study area. New evidences have also emerged on the inter-basin groundwater transfer. Two distinct regional basaltic aquifers (upper and lower) are identified showing distinct hydrochemical and isotopic signatures. In the southern part of the study area the upper and lower aquifers form one unconfined regional aquifer system. In the northern and central part of the basin, it appears that the two systems are separated by regional aquiclude forming confined aquifers, in places with artesian wells. The groundwater from the deep exploratory wells (>250 m) tapping the lower basaltic aquifer and wells located in the south were found to be moderately mineralized (TDS: 400-600 mg/l), with relatively depleted stable isotope composition and with almost zero tritium. In contrast, the upper shallow aquifer has lesser ionic concentration, more isotopically enriched. Evidences from the different methods clearly indicate inter-basin groundwater transfer from the Blue Nile basin to the Upper Awash basin. The evidences also converge to testify common origin of recharge, presence of hydraulic connectivity for systems tapping the lower basaltic aquifer. This has enormous

  12. Impacts of conservation tillage on the hydrological and agronomic performance of fanya juus in the upper Blue Nile (Abbay) river basin

    NASA Astrophysics Data System (ADS)

    Temesgen, M.; Uhlenbrook, S.; Simane, B.; van der Zaag, P.; Mohamed, Y.; Wenninger, J.; Savenije1, H. H. G.

    2012-01-01

    Adoption of soil conservation structures (SCS) has been low in high rainfall areas of Ethiopia mainly due to crop yield reduction, increased soil erosion following breaching of SCS, incompatibility with the tradition of cross plowing and water-logging behind SCS. A new type of conservation tillage (CT) involving contour plowing and the construction of invisible subsoil barriers using a modified Maresha winged "subsoiler" is suggested as a means to tackle these problems as an integral part of the SCS. We investigated the effect of integrating the CT with SCS on the surface runoff, water-logging, soil loss, crop yield and plowing convenience. The new approach of conservation tillage has been compared with traditional tillage (TT) on 5 farmers' fields in a high rainfall area in the upper Blue Nile (Abbay) river basin. Test crops were wheat [triticum vulgare] and tef [eragrostis tef]. Farmers found CT convenient to apply between SCS. Surface runoff appeared to be reduced under CT by 48 and 15%, for wheat and tef, respectively. As a result, CT reduced sediment yield by 51 and 9.5%, for wheat and tef, respectively. Significantly reduced water-logging was observed behind SCS in CT compared to TT. Grain yields of wheat and tef increased by 35 and 10%, respectively, although the differences were not statistically significant apparently due to high fertility variations among fields of participating farmers. Farmers who tested CT indicated that they will continue this practice in the future.

  13. Impacts of conservation tillage on the hydrological and agronomic performance of Fanya juus in the upper Blue Nile (Abbay) river basin

    NASA Astrophysics Data System (ADS)

    Temesgen, M.; Uhlenbrook, S.; Simane, B.; van der Zaag, P.; Mohamed, Y.; Wenninger, J.; Savenije, H. H. G.

    2012-12-01

    Adoption of soil conservation structures (SCS) has been low in high rainfall areas of Ethiopia mainly due to crop yield reduction, increased soil erosion following breaching of SCS, incompatibility with the tradition of cross plowing and water-logging behind SCS. A new type of conservation tillage (CT) involving contour plowing and the construction of invisible subsoil barriers using a modified Maresha winged "subsoiler" is suggested as a means to tackle these problems as an integral part of the SCS. We investigated the effect of integrating the CT with SCS on the surface runoff, water-logging, soil loss, crop yield and plowing convenience. The new approach of conservation tillage has been compared with traditional tillage (TT) on 5 farmers' fields in a high rainfall area in the upper Blue Nile (Abbay) river basin. Test crops were wheat [triticum vulgare] and tef [eragrostis tef]. Farmers found CT convenient to apply between SCS. Surface runoff appeared to be reduced under CT by 48 and 15%, for wheat and tef, respectively. As a result, CT reduced sediment yield by 51 and 9.5%, for wheat and tef, respectively. Significantly reduced water-logging was observed behind SCS in CT compared to TT. Grain yields of wheat and tef increased by 35 and 10%, respectively, although the differences were not statistically significant apparently due to high fertility variations among fields of participating farmers. Farmers who tested CT indicated that they will continue this practice in the future.

  14. Nile Delta

    Atmospheric Science Data Center

    2013-04-15

    article title:  The Nile River Delta     View Larger Image ... of eastern Africa. At the apex of the fertile Nile River Delta is the Egyptian capital city of Cairo. To the west are the Great Pyramids ...

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

    PubMed

    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

  16. 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

    NASA Astrophysics Data System (ADS)

    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.

  17. ECOLOGICAL DETERMINANTS OF AVIAN INFLUENZA VIRUS, WEST NILE VIRUS, AND AVIAN PARAMYXOVIRUS INFECTION AND ANTIBODY STATUS IN BLUE-WINGED TEAL (ANAS DISCORS) IN THE CANADIAN PRAIRIES.

    PubMed

    Nallar, Rodolfo; Papp, Zsuzsanna; Leighton, Frederick A; Epp, Tasha; Pasick, John; Berhane, Yohannes; Lindsay, Robbin; Soos, Catherine

    2016-01-01

    The Canadian prairies are one of the most important breeding and staging areas for migratory waterfowl in North America. Hundreds of thousands of waterfowl of numerous species from multiple flyways converge in and disperse from this region annually; therefore this region may be a key area for potential intra- and interspecific spread of infectious pathogens among migratory waterfowl in the Americas. Using Blue-winged Teal (Anas discors, BWTE), which have the most extensive migratory range among waterfowl species, we investigated ecologic risk factors for infection and antibody status to avian influenza virus (AIV), West Nile virus (WNV), and avian paramyxovirus-1 (APMV-1) in the three prairie provinces (Alberta, Saskatchewan, and Manitoba) prior to fall migration. We used generalized linear models to examine infection or evidence of exposure in relation to host (age, sex, body condition, exposure to other infections), spatiotemporal (year, province), population-level (local population densities of BWTE, total waterfowl densities), and environmental (local pond densities) factors. The probability of AIV infection in BWTE was associated with host factors (e.g., age and antibody status), population-level factors (e.g., local BWTE population density), and year. An interaction between age and AIV antibody status showed that hatch year birds with antibodies to AIV were more likely to be infected, suggesting an antibody response to an active infection. Infection with AIV was positively associated with local BWTE density, supporting the hypothesis of density-dependent transmission. The presence of antibodies to WNV and APMV-1 was positively associated with age and varied among years. Furthermore, the probability of being WNV antibody positive was positively associated with pond density rather than host population density, likely because ponds provide suitable breeding habitat for mosquitoes, the primary vectors for transmission. Our findings highlight the importance of

  18. Nile River

    Atmospheric Science Data Center

    2013-04-15

    article title:  Nile River Fluctuations Near Khartoum, Sudan     ... history, the rising and falling waters of the mighty Nile River have directly impacted the lives of the people who live along its banks. ... the area around Sudan's capital city of Khartoum capture the river's dynamic nature. Acquired by the Multi-angle Imaging SpectroRadiometer ...

  19. Inter-annual and seasonal trends of vegetation condition in the Upper Blue Nile (Abbay) basin: dual scale time series analysis

    NASA Astrophysics Data System (ADS)

    Teferi, E.; Uhlenbrook, S.; Bewket, W.

    2015-02-01

    A long-term decline in ecosystem functioning and productivity, often called land degradation, is a serious environmental and development challenge to Ethiopia that needs to be understood so as to develop sustainable land use strategies. This study examines inter-annual and seasonal trends of vegetation cover in the Upper Blue Nile (UBN) or Abbay basin. Advanced Very High Resolution Radiometer (AVHRR) based Global Inventory, Monitoring, and Modelling Studies (GIMMS) Normalized Difference Vegetation Index (NDVI) was used for course scale long-term vegetation trend analysis. Moderate-resolution Imaging Spectroradiometer (MODIS) NDVI data (MOD13Q1) was used for finer scale vegetation trend analysis. Harmonic analyses and non-parametric trend tests were applied to both GIMMS NDVI (1981-2006) and MODIS NDVI (2001-2011) data sets. Based on a robust trend estimator (Theil-Sen slope) most part of the UBN (~77%) showed a positive trend in monthly GIMMS NDVI with a mean rate of 0.0015 NDVI units (3.77% yr-1), out of which 41.15% of the basin depicted significant increases (P < 0.05) with a mean rate of 0.0023 NDVI units (5.59% yr-1) during the period. However, the finer scale (250 m) MODIS-based vegetation trend analysis revealed that about 36% of the UBN shows a significantly decreasing trend (P < 0.05) over the period 2001-2011 at an average rate of 0.0768 NDVI yr-1. This indicates that the greening trend of vegetation condition was followed by browning trend since the mid-2000s in the basin, which requires the attention of land users and decision makers. Seasonal trend analysis was found to be very useful in identifying changes in vegetation condition that could be masked if only inter-annual vegetation trend analysis was performed. The finer scale intra-annual trend analysis revealed trends that were more linked to human activities. This study concludes that integrated analysis of course and fine scale, inter-annual and intra-annual trends enables a more robust

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

    NASA Astrophysics Data System (ADS)

    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

  1. Determining the Palaeodrainage of the Nile River from a Provenance Study of the Nile Delta Cone Sediments

    NASA Astrophysics Data System (ADS)

    Fielding, L.; Najman, Y.; Millar, I.; Butterworth, P.; Garzanti, E.; Kneller, B. C.

    2014-12-01

    This study documents the palaeodrainage history of the Nile River, in particular the time of its transition from a small locally sourced drainage network to the initiation of an extensive catchment. Today, the Nile drains as far south as Lake Victoria, with the White Nile draining largely cratonic rocks of Archean to Proterozoic age and the Blue Nile draining Cenozoic Ethiopian Continental Flood Basalts and Neoproterozoic basement. However, the timing of catchment expansion to the river's current extent is highly debated. Two end member models are: A) The Blue Nile did not connect with the lower Nile until the Late Messinian, and the White Nile not until 0.5 Ma. In this model, the pre-Messinian Nile delta sediments are locally derived from the Red Sea Hills (RSH) (Issawi and McCauley 1992). B) The Blue Nile has been connected to the lower Nile since the Oligocene (Burke and Wells 1989). Onshore fieldwork characterised each possible source area (Ethiopian flood basalts, Archean craton, and Neoproterozoic basement and Phanerozoic cover sequences of the RSH) using petrography, geochemistry and isotope studies. Tertiary-aged Nile delta sediments provide a unique archive of the river's palaeodrainage history, which were analysed from conventional core from exploration and appraisal wells in order to identify the occurrence (if any) of these sources in the delta geological record. Heavy mineral, petrographic, U/Pb rutile and Lu/Hf zircon analyses indicate Blue Nile and/or RSH input to the Nile delta since at least the Oligocene with very little input from the White Nile. Sr and Nd whole-rock analyses of mud samples allow discrimination between the Blue Nile and RSH sources and may, subject to further analyses, confirm Blue Nile input to the delta since the Oligocene. U-Pb zircon analyses reveal the presence of 20-30 Ma zircons in both the modern river sediments from the Ethiopian Highlands and the Nile Delta core from the early Miocene to present day indicating a

  2. 20,000 years of Nile River dynamics and environmental changes in the Nile catchment area as inferred from Nile upper continental slope sediments

    NASA Astrophysics Data System (ADS)

    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.

  3. Geochemistry of sediments and surface soils from the Nile Delta and lower Nile valley studied by epithermal neutron activation analysis

    NASA Astrophysics Data System (ADS)

    Arafa, Wafaa M.; Badawy, Wael M.; Fahmi, Naglaa M.; Ali, Khaled; Gad, Mohamed S.; Duliu, Octavian G.; Frontasyeva, Marina V.; Steinnes, Eiliv

    2015-07-01

    The distributions of 36 major and trace elements in 40 surface soil and sediment samples collected from the Egyptian section of the river Nile were determined by epithermal neutron activation analysis and compared with corresponding data for the Upper Continental Crust and North American Shale Composite. Their relative distributions indicate the presence of detrital material of igneous origin, most probably resulting from weathering on Ethiopian highlands and transported by the Blue Nile, the Nile main tributary. The distributions of the nickel, zinc, and arsenic contents suggest that the lower part of the Nile and its surroundings including the Nile Delta is not seriously polluted with metals from local human activity. The geographical distributions of Na, Cl, and I as well as results of principal component analysis suggest atmospheric supply of these elements from the ocean. In general the present data may contribute to a better understanding of the geochemistry of the Nile sediments.

  4. Shifting Sediment Sources in the Quaternary Nile

    NASA Astrophysics Data System (ADS)

    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.

  5. West Nile virus

    MedlinePlus

    West Nile virus is a disease spread by mosquitoes. The condition ranges from mild to severe. ... West Nile virus was first identified in 1937 in Uganda in eastern Africa. It was first discovered in the U.S. in ...

  6. Risky Sexual Behaviors among Female Youth in Tiss Abay, a Semi-Urban Area of the Amhara Region, Ethiopia

    PubMed Central

    Tadesse, Gojjam; Yakob, Bereket

    2015-01-01

    Background Little is known about sexual risks and associated factors about female youths in semi-urban areas of Ethiopia. This study aimed to describe the nature and magnitude of risky sexual behaviors, and the socio-demographic and behavioral determinants among female youths in Tiss Abay, a semi-urban area on the outskirts of Bahir Dar City of the Amhara Region in northern Ethiopia. Methods A cross-sectional census type study was conducted among female youths who were unmarried and aged 15–29 years in September 2011. Results 711 female youths participated in the study, with the mean age of initiation of sex of 78.6% being16.73±2.53 years. Only 52(9.3%) used condom during the first sex. Within the last 12 months, 509(71.6%) had sexual intercourse and 278(54.6%) had two or more sex partners, and 316(62.1%) did not use condom during their last sex. Sex under the influence of substances was reported by 350(68.8%), and a third of the recent sexes were against the will of participants. One or more risky sexual practices were reported by 503(70.3%) participants, including: multiple sexual partnerships, inconsistently using or not using condoms, sex under the influence of alcohol and/or sex immediately after watching pornography. Age group, current marital status, drinking homemade alcohol, chewing ‘khat’, watching pornography and using any form of stimulant substances were the predictors of risky sexual behavior. Watching pornography before sex and sex for transaction were the predicators of not using condom during most recent sex. Conclusions Risky sexual behaviors were very common among the female youths in Tiss Abay. Initiation of context-based interventions, such as raising awareness about the risks, safer sex practices, condom promotion and integration of gender issues in the programs are recommended. PMID:25738508

  7. Late Quaternary environments and prehistoric occupation in the lower White Nile valley, central Sudan

    NASA Astrophysics Data System (ADS)

    Williams, Martin A. J.; Usai, Donatella; Salvatori, Sandro; Williams, Frances M.; Zerboni, Andrea; Maritan, Lara; Linseele, Veerle

    2015-12-01

    Despite the major contributions provided over fifty years ago by A.J. Arkell and J.D. Tothill to our understanding of late Quaternary environments and prehistoric occupation near the confluence of the Blue and White Nile in central Sudan, three key questions have remained unresolved since then. (a) Was the decline in Nile flood levels from early Holocene times onwards caused by a reduction in Nile discharge, or by channel incision, or both? (b) Was the regional climate wetter during times of high Nile floods and drier during times of low Nile floods? (c) Given the high degree of disturbance of Mesolithic and later prehistoric sites, is it possible to identify primary-context, stratified and undisturbed occupation? Drawing upon dated evidence from three sites to the east of and three to the west of the lower White Nile, we provide a qualified answer to the first question and documented affirmative answers to the second and third questions.

  8. Predicting streamflow for land cover changes in the Upper Gilgel Abay River Basin, Ethiopia: A TOPMODEL based approach

    NASA Astrophysics Data System (ADS)

    Gumindoga, W.; Rientjes, T. H. M.; Haile, A. T.; Dube, T.

    Hydrological effects of land cover changes and runoff contributions from respective land cover types are analysed for the Upper Gilgel Abay basin in Ethiopia. Runoff production and streamflow are simulated by the TOPMODEL approach. For impact assessment of land cover changes, satellite based land covers for the years 1973, 1986 and 2001 are considered. Catchment topography as well as land cover and vegetation characteristics are derived from satellite images and serve to estimate model parameters. Land cover in TOPMODEL has been implemented by spatial units based on the actual size of each land cover type. The topographic index distribution function, which is an important input to the TOPMODEL, is prepared for each land cover type. Simulations are also performed for specific land cover types to allow inter comparison of hydrological responses. Results showed that the highest peak flow as well as the annual streamflow volume varied among the land cover types agriculture, forest and grassland which dominate land cover in the catchment. Results of this study show that in data poor basins, satellite images provide suitable land surface data for rainfall-runoff modelling and land surface parameterization. Findings are of relevance for many African rural catchments which experience rapid population increases and resource scarcity.

  9. The Nile River

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This image of the northern portion of the Nile River was captured by MISR's nadir camera on January 30, 2001 (Terra orbit 5956). The Nile is the longest river in the world, extending for about 6700 kilometers from its headwaters in the highlands of eastern Africa. At the apex of the fertile Nile River Delta is the Egyptian capital city of Cairo. To the west are the Great Pyramids of Giza. North of here the Nile branches into two distributaries, the Rosetta to the west and the Damietta to the east. Also visible in this image is the Suez Canal, a shipping waterway connecting Port Said on the Mediterranean Sea with the Gulf of Suez. The Gulf is an arm of the Red Sea, and is located on the righthand side of the picture. Image credit: NASA/GSFC/LaRC/JPL, MISR Team.

  10. A White Nile megalake during the last interglacial period

    NASA Astrophysics Data System (ADS)

    Barrows, Timothy T.; Williams, Martin A. J.; Mills, Stephanie C.; Duller, Geoff A. T.; Fifield, L. Keith; Haberlah, David; Tims, Stephen G.; Williams, Frances M.

    2014-05-01

    The eastern Sahara Desert of Africa is one of the most climatically sensitive areas on Earth, varying from lake-studded savannah woodland to hyperarid desert over the course of a glacial-interglacial cycle. In currently semiarid Sudan there is widespread evidence that a very large freshwater lake once filled the White Nile River valley (Barrows et al., 2014). Here we present the first quantitative estimate for the dimensions of the lake and a direct age for the emplacement of its shoreline. Using a profile dating approach with the cosmogenic nuclide 10Be, we estimate an exposure age of 109 ± 8 ka for this megalake, indicating that it probably formed during the last interglacial period. This age is supported by optically stimulated luminescence dating of Blue Nile paleochannels associated with the lake. Using a high-resolution digital elevation model, we estimate that the lake was more than 45,000 km2 in area, making it comparable to the largest freshwater lakes on Earth today. We attribute the lake's existence to seasonal flood pulses as a result of local damming of the White Nile by a more southern position of the Blue Nile and greatly increased precipitation associated with an enhanced monsoon. References Barrows, T.T., Williams, M.A.J., Mills, S.C., Duller, G.A.T., Fifield, L.K., Haberlah, D., Tims, S.G., Williams, F.M., 2014. A White Nile megalake during the last interglacial period. Geology. 10.1130/g35238.1

  11. Nile River Delta, Egypt

    NASA Technical Reports Server (NTRS)

    1984-01-01

    The Nile River Delta of Egypt (30.0N, 31.0E) irrigated by the Nile River and its many distributaries, is some of the richest farm land in the world and home to some 45 million people, over half of Egypt's population. The capital city of Cairo is at the apex of the delta. Just across the river from Cairo can be seen the ancient three big pyramids and sphinx at Giza and the Suez Canal is just to the right of the delta.

  12. Nile Delta, Egypt

    NASA Technical Reports Server (NTRS)

    1982-01-01

    The Nile Delta of Egypt (30.0N, 31.0E) irrigated by the Nile River and its many distributaries, is some of the richest farm land in the world and home to some 45 million people, over half of Egypt's population of 57 million. The capital city of Cairo is at the apex of the delta in the middle of the scene. Across the river from Cairo can be seen the three big pyramids and sphinx at Giza and the Suez Canal is just to the right of the delta.

  13. Holocene Floods and Sediment Sources in the Desert Nile: a Strontium Isotope Record from Northern Sudan

    NASA Astrophysics Data System (ADS)

    Woodward, Jamie; Macklin, Mark; Millar, Ian; Williams, Martin; Welsby, Derek; Duller, Geoff; Williams, Frances

    2014-05-01

    Strontium isotope ratios can be used to explore changes in Nile sediment sources and flood regime because the Blue Nile/Atbara and White Nile headwater catchments lie in markedly contrasting geological settings. Most of the existing Sr isotope data for the Holocene Nile has been obtained from lagoonal/lacustrine environments rather than directly from the fluvial sediments of the desert Nile. Northern Sudan contains some of the best preserved Holocene river deposits and landforms in the desert Nile. Using Optically Stimulated Luminescence (OSL) and radiocarbon dating, we have compiled a detailed record of Holocene river history in the Northern Dongola Reach (NDR) that spans the last c. 8500 years. This period includes major changes in global climate and Nile hydrological regime. In the palaeochannel fills and floodplain deposits of the NDR, we have sampled sedimentary units that represent discrete flood events. We have measured Sr and Nd isotopes on the fine-grained fraction of dated alluvial units. The Sr isotope signature of the NDR fluvial sediments is discussed and compared to published datasets for the Nile delta.

  14. Discover the Nile River

    ERIC Educational Resources Information Center

    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.

  15. FAQ: West Nile Virus and Dead Birds

    MedlinePlus

    ... Education Public Service Videos West Nile Virus & Dead Birds Recommend on Facebook Tweet Share Compartir On this ... dead bird sightings to local authorities. How do birds get infected with West Nile virus? West Nile ...

  16. The Carbon Cycle at the Nile Headwaters

    NASA Astrophysics Data System (ADS)

    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

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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. Mental Status after West Nile Virus Infection

    PubMed Central

    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). PMID:16965710

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

    NASA Astrophysics Data System (ADS)

    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.

  1. Solar Forcings on Nile and Earthquakes

    NASA Astrophysics Data System (ADS)

    Al-Shehri, Saad Mohammed; Sabbah, Ismail; Yousef, Shahinaz Moustafa; Amin, Magdy Y.

    2013-03-01

    Nile and earthquake periodicities are examined in the light of solar and geomagnetic periodicities in order to uncover the role of the sun in initiating such terrestrial phenomena. The Nile periodicities under considerations covers the period 622-1420 AD. 1749- 1800 and 1870-1945 and are taken from an earlier paper by Yousef and El-Rae (1995). It is found that 11 yr and 21 yr solar periodicities affected the White Nile originating from the Equatorial plateau. On the other hand the Blue Nile arising mainly from Lake Tana in Ethiopia was affected mostly by the 3.3 yr, 2.9 yr, 2.7 yr, and the 2.52 yr periodicities. Such short periodicities are also present in cosmic rays. This is fairly true as during weak solar cycles series at the bottom of the 80-120 year Solar Wolf-Gleissberg Cycles, the level of the second to last of the weak cycles rise and fall coherently with full solar cycles with a correlation coefficient of about 0.9. Rain over Ethiopia is affected by the Monsoon precipitation which is related to the quasi biennial oscillations QBO of the equatorial zonal wind between the easterlies and the westerlies in the tropical stratosphere with a mean period of 29 months. We propose that the QBO are stimulated by the 2.52-2.48 yr solar periodicities. The 2.52 and 2.48 yr periodicity is strong in odd solar cycles 21 and 23. Generally speaking, it looks that different solar periodicities are space-time dependant and that they affect different regimes of terrestrial responses. In the case of earthquakes, we think that they are related to geomagnetic storms initiated by solar stimuli. Several solar periodicities are found in earthquakes. We postulate that electric currents in the ring current and in the ionosphere induce surface as well as deep electric currents in the magma thus produce motion and disturbances of the plates and the magma leading to earthquakes and volcanoes.

  2. Monitoring the Spread of West Nile Virus with Satellite Data

    NASA Technical Reports Server (NTRS)

    2002-01-01

    A NASA-funded study uses temperature and vegetation data from satellites to help track and predict where West Nile virus is spreading in North America. Scientists and public health officials hope one day to use near real-time maps to focus resources and stave off the disease more efficiently. This image is a composite of land surface temperatures (LST) recorded between 1997 and 2000 and was used to help monitor and predict the spread of West Nile virus in the United States. In the color figure above, the mean land surface temperatures are in red; annual amplitude-or the difference between low and high annual temperatures-is in blue; and annual phase-or the timing of annual temperature peaks-appears in green. Brighter colors mean higher values. The major north-south temperature difference (dull red in the upper part of the image to bright red in the lower part) is considerably affected by the Rockies in the west and to a much lesser extent by the Appalachians in the east. The brighter blue in the upper part of the image indicates the big difference between highest and lowest temperatures during the course of a year at higher latitudes. There is less variation in the timing of the annual peak of land surface temperatures, which occurs earlier in the south than in the north. Black dots superimposed on this image are the locations (county geo-centers) where birds infected with West Nile virus were reported between January and October 2001. Scientists working with the International Research Partnership for Infectious Diseases (INTREPID) program based at NASA are using such imagery to define and predict the conditions where mosquitoes transmit West Nile virus in the U.S. The conclusion reached about the importance of any single variable depends both upon its value and context. A temperature of 30o Celsius (86o Fahrenheit) might be fatal for a mosquito at low humidity but survivable at higher humidities. The work done here on West Nile virus and other diseases shows very

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

    NASA Astrophysics Data System (ADS)

    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

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

    NASA Astrophysics Data System (ADS)

    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.

  5. The modern Nile sediment system: Processes and products

    NASA Astrophysics Data System (ADS)

    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

  6. Nile River, Lake Nasser, Aswan Dam, Egypt

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Egypt's High Aswan Dam on the Nile River at the first cataracts, Nile River, (24.0N, 33.0E) was completed in 1971 to provide cheap hydroelectric power and to regulate the historically uneven flow of the Nile River. The contrast between the largely base rock desert east of the Nile versus the sand covered desert west of the river and the ancient irrigated floodplain downstream from the damsite is clearly shown.

  7. Antibody response of five bird species after vaccination with a killed West Nile virus vaccine.

    PubMed

    Okeson, Danelle M; Llizo, Shirley Yeo; Miller, Christine L; Glaser, Amy L

    2007-06-01

    West Nile virus has been associated with numerous bird mortalities in the United States since 1999. Five avian species at three zoological parks were selected to assess the antibody response to vaccination for West Nile virus: black-footed penguins (Spheniscus demersus), little blue penguins (Eudyptula minor), American flamingos (Phoenicopterus ruber), Chilean flamingos (Phoenicopterus chilensis), and Attwater's prairie chickens (Tympanuchus cupido attwateri). All birds were vaccinated intramuscularly at least twice with a commercially available inactivated whole virus vaccine (Innovator). Significant differences in antibody titer over time were detected for black-footed penguins and both flamingo species. PMID:17679507

  8. West Nile Virus Infection.

    PubMed

    Sejvar, James J

    2016-06-01

    Although long recognized as a human pathogen, West Nile virus (WNV) emerged as a significant public health problem following its introduction and spread across North America. Subsequent years have seen a greater understanding of all aspects of this viral infection. The North American epidemic resulted in a further understanding of the virology, pathogenesis, clinical features, and epidemiology of WNV infection. Approximately 80% of human WNV infections are asymptomatic. Most symptomatic people experience an acute systemic febrile illness; less than 1% of infected people develop neuroinvasive disease, which typically manifests as meningitis, encephalitis, or anterior myelitis resulting in acute flaccid paralysis. Older age is associated with more severe illness and higher mortality; other risk factors for poor outcome have been challenging to identify. In addition to natural infection through mosquito bites, transfusion- and organ transplant-associated infections have occurred. Since there is no definitive treatment for WNV infection, protection from mosquito bites and other preventative measures are critical. WNV has reached an endemic pattern in North America, but the future epidemiologic pattern is uncertain. PMID:27337465

  9. The White Nile sedimentary system

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

    The Nile River flows for ~6700 km from south of the Equator to finally reach the Mediterranean Sea at northern subtropical latitudes (Woodward et al. 2007). This is the longest sedimentological laboratory on Earth, a unique setting in which we are investigating changes in sediment composition associated with diverse chemical and physical processes, including weathering and hydraulic sorting. The present study focuses on the southern branch of the Nile across 20° of latitude, from hyperhumid Burundi and Rwanda highlands in central Africa to Khartoum, the capital city of Sudan at the southern edge of the Sahara. Our study of the Kagera basin emphasizes the importance of weathering in soils at the source rather than during stepwise transport, and shows that the transformation of parent rocks into quartzose sand may be completed in one sedimentary cycle (Garzanti et al. 2013a). Micas and heavy minerals, less effectively diluted by recycling than main framework components, offer the best key to identify the original source-rock imprint. The different behaviour of chemical indices such as the CIA (a truer indicator of weathering) and the WIP (markedly affected by quartz dilution) helps us to distinguish strongly weathered first-cycle versus polycyclic quartz sands (Garzanti et al. 2013b). Because sediment is efficiently trapped in East African Rift lakes, the composition of Nile sediments changes repeatedly northwards across Uganda. Downstream of both Lake Kyoga and Lake Albert, quartzose sands are progressively enriched in metamorphiclastic detritus supplied from tributaries draining amphibolite-facies basements. The evolution of White Nile sediments across South Sudan, a scarcely accessible region that suffered decades of civil war, was inferred from the available information (Shukri 1950), integrated by original petrographic, heavy-mineral and geochemical data (Padoan et al. 2011). Mineralogical and isotopic signatures of Bahr-el-Jebel and Sobat sediments, derived

  10. Blue Note

    ScienceCinema

    Murray Gibson

    2010-01-08

    Argonne's Murray Gibson is a physicist whose life's work includes finding patterns among atoms. The love of distinguishing patterns also drives Gibson as a musician and Blues enthusiast."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.

  11. Blue Note

    SciTech Connect

    Murray Gibson

    2007-04-27

    Argonne's Murray Gibson is a physicist whose life's work includes finding patterns among atoms. The love of distinguishing patterns also drives Gibson as a musician and Blues enthusiast."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.

  12. Socioeconomic dynamics of water quality in the Egyptian Nile

    NASA Astrophysics Data System (ADS)

    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

  13. Hydro-economic Risk Assessment in the Eastern Nile River Basin

    NASA Astrophysics Data System (ADS)

    Arjoon, D.; Tilmant, A.; Mohamed, Y.

    2013-12-01

    In 2011, the Ethiopian government announced plans for the construction of the Grand Renaissance Dam (GRD) on the Blue Nile, just east of its border with Sudan, at a cost of almost 5 billion dollars. The project is expected to generate over 15 TWh of energy and will include a reservoir of more than 60 km3 capacity, which roughly corresponds to the average annual flow of the Blue Nile. This project is part of a larger scheme, by the government, to expand its hydroelectric power capacity, however, the scheme faces strong opposition from downstream Egypt and Sudan. Egypt and Sudan are highly dependent on flows that originate in Ethiopia (it has been estimated that 86% of Nile flow originates in the Ethiopian highlands). The Ethiopian government argues that the dam would supply electricity for Ethiopians as well as generate surplus energy for export to neighboring countries. The Ethiopians also argue that the huge reservoir would generate positive externalities downstream by reducing floods and providing more constant and predictable lows. This study attempts to provide an independent analysis of the hydrologic and economic risks faced by downstream countries when GRD will be online. To achieve this, an integrated, stochastic hydro-economic model of the entire Eastern Nile basin is used to analyze various development and management scenarios. The results indicate that if countries agree to co- operative management of the Eastern Nile River basin, GRD would indeed significantly increase basin-wide benefits, especially in Ethiopia and in Sudan. An alternative management scenario, whereby GRD would be operated by Sudan and Egypt, does not yield significant economic gains in these countries. However, massive unilateral irrigation developments in Ethiopia will be detrimental for all countries, including Ethiopia itself, due to the huge opportunity costs involved.

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

    NASA Astrophysics Data System (ADS)

    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 < 126 (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.

  15. A distal 145 ka sediment record of Nile discharge and East African monsoon variability

    NASA Astrophysics Data System (ADS)

    Ehrmann, W.; Schmiedl, G.; Seidel, M.; Krüger, S.; Schulz, H.

    2015-09-01

    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. 145 ka. Smectite abundances indicate the influence of the Blue Nile and Atbara 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 humid periods with enhanced sediment discharge at 132 to < 122 ka (AHP 5), 113 to 104 ka (AHP 4), and 86 to 74 ka (AHP 3). They lasted much longer than the formation of the related sapropel layers S5, S4 and S3. During the last glacial period (MIS 4-2) the long-term changes of the monsoonal system were superimposed by millennial-scale changes of an intensified mid-latitude 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.

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

    PubMed

    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

  17. West Nile Virus and wildlife

    USGS Publications Warehouse

    Marra, P.P.; Griffing, S.; Caffrey, C.; Kilpatrick, A.M.; McLean, R.; Brand, C.; Saito, E.; Dupuis, A.P.; Kramer, L.; Novak, R.

    2004-01-01

    West Nile virus (WNV) has spread rapidly across North America, resulting in human deaths and in the deaths of untold numbers of birds, mammals, and reptiles. The virus has reached Central America and the Caribbean and may spread to Hawaii and South America. Although tens of thousands of birds have died, and studies of some bird species show local declines, few regionwide declines can be attributed to WNV. Predicting future impacts of WNV on wildlife, and pinpointing what drives epidemics, will require substantial additional research into host susceptibility, reservoir competency, and linkages between climate, mosquitoes, and disease. Such work will entail a collaborative effort between scientists in governmental research groups, in surveillance and control programs, and in nongovernmental organizations. West Nile virus was not the first, and it will not be the last, exotic disease to be introduced to the New World. Its spread in North America highlights the need to strengthen animal monitoring programs and to integrate them with research on disease ecology.

  18. FAQ: General Questions about West Nile Virus

    MedlinePlus

    ... or meningitis (inflammation of the lining of the brain and spinal cord). West Nile virus transmission has been documented in Europe and the Middle East, Africa, India, parts of Asia, and Australia. It was first detected ...

  19. West Nile virus: North American experience

    USGS Publications Warehouse

    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.

  20. 21 CFR 866.3940 - West Nile virus serological reagents.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false West Nile virus serological reagents. 866.3940... virus serological reagents. (a) Identification. West Nile virus serological reagents are devices that consist of antigens and antisera for the detection of anti-West Nile virus IgM antibodies, in human...

  1. 21 CFR 866.3940 - West Nile virus serological reagents.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false West Nile virus serological reagents. 866.3940... virus serological reagents. (a) Identification. West Nile virus serological reagents are devices that consist of antigens and antisera for the detection of anti-West Nile virus IgM antibodies, in human...

  2. 21 CFR 866.3940 - West Nile virus serological reagents.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false West Nile virus serological reagents. 866.3940... virus serological reagents. (a) Identification. West Nile virus serological reagents are devices that consist of antigens and antisera for the detection of anti-West Nile virus IgM antibodies, in human...

  3. 21 CFR 866.3940 - West Nile virus serological reagents.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false West Nile virus serological reagents. 866.3940... virus serological reagents. (a) Identification. West Nile virus serological reagents are devices that consist of antigens and antisera for the detection of anti-West Nile virus IgM antibodies, in human...

  4. 21 CFR 866.3940 - West Nile virus serological reagents.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false West Nile virus serological reagents. 866.3940... virus serological reagents. (a) Identification. West Nile virus serological reagents are devices that consist of antigens and antisera for the detection of anti-West Nile virus IgM antibodies, in human...

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

    NASA Astrophysics Data System (ADS)

    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.

  6. 21,000 years of Ethiopian African monsoon variability recorded in sediments of the western Nile deep-sea fan: impact of the Nile freshwater inflow for the Mediterranean thermo-haline circulation

    NASA Astrophysics Data System (ADS)

    Revel, Marie; Colin, Christophe; Bernasconi, Stephano; Combourieu-Nebout, Nathalie; Ducassou, Emmanuelle; Rolland, Yann; Bosch, Delphine

    2014-05-01

    The Nile delta sedimentation constitutes a continuous high resolution (1.6 mm/year) record of Ethiopian African monsoon regime intensity. Multiproxy analyses performed on core MS27PT recovered in hemipelagic Nile sediment margin (<90 km outward of the Rosetta mouth of the Nile) allow the quantification of the Saharan aeolian dust and the Blue/White Nile River suspended matter frequency fluctuations during the last 21 cal. ka BP. The radiogenic Sr and Nd isotopes, clay mineralogy, bulk elemental composition and palynological analyses reveal large changes in source components, oscillating between a dominant aeolian Saharan contribution during the LGM and the Late Holocene (~4 to 2 cal. ka BP), a dominant Blue/Atbara Nile River contribution during the early Holocene (15 to 8.4 cal. ka BP) and a probable White Nile River contribution during the Middle Holocene (8.4 to 4 cal. ka BP). The following main features are highlighted: 1. The rapid shift from the LGM arid conditions to the African Humid Period (AHP) started at about 15 cal. ka BP. AHP extends until 8.4 cal. ka BP, and we suggest that the Ethiopian African Monsoon maximum between 12 and 8 cal. ka BP is responsible for a larger Blue/Atbara Nile sediment load and freshwater input into the Eastern Mediterranean Sea. 2. The transition between the AHP and the arid Late Holocene is gradual and occurs in two main phases between 8.4 and 6.5 cal. ka BP and 6.5 to 3.2 cal. ka BP. We suggest that the main rain belt shifted southward from 8.4 to ~4 cal. ka BP and was responsible for progressively reduced sediment load and freshwater input into the eastern Mediterranean Sea. 3. The aridification along the Nile catchments occurred from ~4 to 2 cal. ka BP. A dry period, which culminates at 3.2 cal. ka BP, and seems to coincide with a re-establishment of increased oceanic primary productivity in the western Mediterranean Sea. We postulate that the decrease in thermo-haline water Mediterranean circulation could be part of a

  7. The Blue Bottle Revisited.

    ERIC Educational Resources Information Center

    Vandaveer, Walter R., IV; Mosher, Mel

    1997-01-01

    Presents a modification of the classic Blue Bottle demonstration that involves the alkaline glucose reduction of methylene blue. Uses other indicators in the classic Blue Bottle to produce a rainbow of colors. (JRH)

  8. Impacts of West Nile Virus on wildlife

    USGS Publications Warehouse

    Saito, E.K.; Wild, M.A.

    2004-01-01

    The recent epidemic of West Nile virus in the United States proved to be unexpectedly active and was the largest epidemic of the virus ever recorded. Much remains to be discovered about the ecology and epidemiology of West Nile virus in the United States, including which species are important in maintaining the virus in nature, why some species are more susceptible to lethal infection, and what environmental factors are important in predicting future epidemics. These factors will likely vary regionally, depending on local ecological characteristics. Until scientists better understand the virus and factors influencing its activity, predicting its effects for future seasons is impossible. However, experts are certain about one thing: West Nile virus is here to stay.

  9. West Nile Virus: Review of the Literature

    PubMed Central

    Petersen, Lyle R.; Brault, Aaron C.; Nasci, Roger S.

    2015-01-01

    IMPORTANCE Since its introduction in North America in 1999,West Nile virus has produced the 3 largest arboviral neuroinvasive disease outbreaks ever recorded in the United States. OBJECTIVE To review the ecology, virology, epidemiology, clinical characteristics, diagnosis, prevention, and control of West Nile virus, with an emphasis on North America. EVIDENCE REVIEW PubMed electronic database was searched through February 5, 2013. United States national surveillance data were gathered from the Centers for Disease Control and Prevention. FINDINGS West Nile virus is now endemic throughout the contiguous United States, with 16 196 human neuroinvasive disease cases and 1549 deaths reported since 1999. More than 780 000 illnesses have likely occurred. To date, incidence is highest in the Midwest from mid-July to early September. West Nile fever develops in approximately 25% of those infected, varies greatly in clinical severity, and symptoms may be prolonged. Neuroinvasive disease (meningitis, encephalitis, acute flaccid paralysis) develops in less than 1% but carries a fatality rate of approximately 10%. Encephalitis has a highly variable clinical course but often is associated with considerable long-term morbidity. Approximately two-thirds of those with paralysis remain with significant weakness in affected limbs. Diagnosis usually rests on detection of IgM antibody in serum or cerebrospinal fluid. Treatment is supportive; no licensed human vaccine exists. Prevention uses an integrated pest management approach, which focuses on surveillance, elimination of mosquito breeding sites, and larval and adult mosquito management using pesticides to keep mosquito populations low. During outbreaks or impending outbreaks, emphasis shifts to aggressive adult mosquito control to reduce the abundance of infected, biting mosquitoes. Pesticide exposure and adverse human health events following adult mosquito control operations for West Nile virus appear negligible. CONCLUSIONS AND

  10. Tracing Nile sediment sources by Sr and Nd isotope signatures (Uganda, Ethiopia, Sudan)

    NASA Astrophysics Data System (ADS)

    Padoan, Marta; Garzanti, Eduardo; Harlavan, Yehudit; Villa, Igor Maria

    2011-06-01

    Strontium and neodymium isotopes, measured on diverse mud and sand fractions of sediment in transit along all major Nile branches, identify detritus sourced from Precambrian basements, Mesozoic strata, and Tertiary volcanic rocks exposed along the shoulders of the East African rift and in Ethiopian highlands. Sr and Nd isotopic ratios reflect the weighted average of detrital components generated in different catchments, allowing us to discriminate provenance, calculate sediment budgets, and investigate grain-size and hydraulic-sorting effects. 87Sr/ 86Sr and 143Nd/ 144Nd range, respectively, from as high as 0.722 and as low as 0.5108 for sediment derived from Archean gneisses in northern Uganda, to 0.705 and 0.5127 for sediment derived from Neoproterozoic Ethiopian and Eritrean basements. 87Sr/ 86Sr and 143Nd/ 144Nd, ranging 0.705-0.709 and 0.5124-0.5130 for Blue Nile tributaries, are 0.704-0.705 and 0.5127-0.5128 for largely volcaniclastic sediments of River Tekeze-Atbara, and 0.705-0.706 and 0.5126-0.5127 for main Nile sediments upstream Lake Nasser. Model mantle derivation ages ( tDM), oldest in Uganda where sediment is principally derived from the Congo Craton (3.4-3.0 Ga for Victoria and Albert Nile), progressively decrease northward across the Saharan Metacraton, from 2.6 Ga (Bahr el Jebel in South Sudan), to 2.4-2.2 Ga (Bahr ez Zeraf across the Sudd), and finally 1.6-1.3 Ga (White Nile upstream Khartoum). Instead, tDM ages of Sobat mud increase from 0.9 to 1.5 Ga across the Machar marshes. TDM ages are younger for sediments shed by Ethiopian (1.2-0.7 Ga) and Eritrean basements (1.5-1.2 Ga), and youngest for sediments shed from Ethiopian flood basalts (0.3-0.2 Ga). Integrated geochemical, mineralogical, and settling-equivalence analyses suggest influence on the Nd isotopic signal by volcanic lithic grains and titanite rather than by LREE-rich monazite or allanite. Because contributions by ultradense minerals is subordinate, intrasample variability of Sr and

  11. Avian hosts for West Nile virus in St. Tammany Parish, Louisiana, 2002.

    PubMed

    Komar, Nicholas; Panella, Nicholas A; Langevin, Stanley A; Brault, Aaron C; Amador, Manuel; Edwards, Eric; Owen, Jennifer C

    2005-12-01

    West Nile virus (WNV) infections in free-ranging birds were studied in Slidell, St. Tammany Parish, Louisiana, after a human encephalitis outbreak peaked there in July 2002. Seroprevalence in resident, free-ranging wild birds in one suburban site was 25% and 24% in August and October, respectively, indicating that most transmission had ceased by early August. Mortality rates, seroprevalence rates, host competence, and crude population estimates were used in mathematical models to predict actual infection rates, population impacts, and importance as amplifying hosts for several common passerine birds. Northern cardinal (Cardinalis cardinalis) and house sparrow (Passer domesticus) were the principal amplifying hosts, but blue jay (Cyanocitta cristata) and northern mockingbird (Mimus polyglottos) also contributed. The blue jay population was reduced by an estimated 47%. A variety of passerine bird species combined to play an important role as amplifying hosts in the WNV transmission cycle. PMID:16354808

  12. Vaccines in development against West Nile virus.

    PubMed

    Brandler, Samantha; Tangy, Frederic

    2013-10-01

    West Nile encephalitis emerged in 1999 in the United States, then rapidly spread through the North American continent causing severe disease in human and horses. Since then, outbreaks appeared in Europe, and in 2012, the United States experienced a new severe outbreak reporting a total of 5,387 cases of West Nile virus (WNV) disease in humans, including 243 deaths. So far, no human vaccine is available to control new WNV outbreaks and to avoid worldwide spreading. In this review, we discuss the state-of-the-art of West Nile vaccine development and the potential of a novel safe and effective approach based on recombinant live attenuated measles virus (MV) vaccine. MV vaccine is a live attenuated negative-stranded RNA virus proven as one of the safest, most stable and effective human vaccines. We previously described a vector derived from the Schwarz MV vaccine strain that stably expresses antigens from emerging arboviruses, such as dengue, West Nile or chikungunya viruses, and is strongly immunogenic in animal models, even in the presence of MV pre-existing immunity. A single administration of a recombinant MV vaccine expressing the secreted form of WNV envelope glycoprotein elicited protective immunity in mice and non-human primates as early as two weeks after immunization, indicating its potential as a human vaccine. PMID:24084235

  13. Tracking Nile Delta vulnerability to Holocene change.

    PubMed

    Marriner, Nick; Flaux, Clément; Morhange, Christophe; Stanley, Jean-Daniel

    2013-01-01

    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. PMID:23922692

  14. Does The Nile Reflect Solar Variability?

    NASA Technical Reports Server (NTRS)

    Ruzmaikin, Alexander; Feynman, Joan; Yung, Yuk

    2006-01-01

    Historical records of the Nile water level provide a unique opportunity to investigate the possibility that solar variability influences the Earth's climate. Particularly important are the annual records of the water level, which are uninterrupted for the years 622-1470 A.D. These records are non-stationary, so that standard spectral analyses cannot adequately characterize them. Here the Empirical Mode Decomposition technique, which is designed to deal with nonstationary, nonlinear time series, becomes useful. It allows the identification of two characteristic time scales in the water level data that can be linked to solar variability: the 88 year period and a time scale of about 200 years. These time scales are also present in the concurrent aurora data. Auroras are driven by coronal mass ejections and the rate of auroras is an excellent proxy for solar variability. Analysis of auroral data contemporaneous with the Nile data shows peaks at 88 years and about 200 years. This suggests a physical link between solar variability and the low frequency variations of the Nile water level. The link involves the influence of solar variability on the North Annual Mode of atmospheric variability and its North Atlantic and Indian Oceans patterns that affect rainfall over Eastern Equatorial Africa where the Nile originates.

  15. West Nile Virus: Symptoms and Treatment

    MedlinePlus

    ... Nile virus infection are available. Over-the-counter pain relievers can be used to reduce fever and relieve some symptoms In severe cases, patients often need to be hospitalized to receive supportive treatment, such as intravenous fluids, pain medication, and nursing ...

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  18. West Nile virus surveillance in East Baton Rouge Parish, Louisiana.

    PubMed

    Gleiser, Raquel M; Mackay, Andrew J; Roy, Alma; Yates, Mathew M; Vaeth, Randy H; Faget, Guy M; Folsom, Alex E; Augustine, William F; Wells, Roderick A; Perich, Michael J

    2007-03-01

    West Nile virus (WNV) was detected for the first time in Louisiana in the fall of 2001. Surveillance data collected from East Baton Rouge Parish in 2002 were examined to establish baseline data on WNV activity, to support the current design of disease surveillance programs, and to target vector control efforts in the parish. The first indications of WNV activity were from a dead Northern Cardinal collected in February and from a live male cardinal sampled on 14 March. In mosquito pools, WNV was first detected on June 11. The onset of the first human case and the first detection of WNV in sentinel chickens occurred concurrently on June 24. The number of reported human cases and minimum infection rates in mosquitoes peaked in July. WNV prevalence in wild birds increased in late August and was highest in December. WNV-positive wild birds and mosquito pools were detected an average of 31 and 59 days in advance of the onset date of reported human cases, respectively, within 5 km of the residence of a human case. Antibodies to WNV were detected in sera from 7 (Northern Cardinal, House Sparrow, Northern Mockingbird, Blue Jay, Hermit Thrush, Yellow-rumped Warbler, and White-throated Sparrow) of the 42 wild bird species tested. Wild bird serology indicated WNV activity during the winter. Out of 18 mosquito species tested, the only species found positive for WNV was Culex quinquefasciatus, a result suggesting that this species was the primary epizootic/epidemic vector. PMID:17536365

  19. Blue-green algae

    MedlinePlus

    ... Talk with your health provider.Medications that slow blood clotting (Anticoagulant / Antiplatelet drugs)Blue-green algae might slow blood clotting. Taking blue-green algae along with medications that ...

  20. Greening the Blue Bottle.

    ERIC Educational Resources Information Center

    Wellman, Whitney E.; Noble, Mark E.

    2003-01-01

    Compares the revised Blue Bottle formulation to the classical Blue Bottle. Indicates that the revised formulation gives a somewhat bluer solution, but initially slower reduction when compared to the classical formulation. (Author/KHR)

  1. The Blue Water

    ERIC Educational Resources Information Center

    Berger, J. Joel

    1973-01-01

    Describes some of the advantages of an elementary science activity in which students discover that blowing through a straw into a bromthymol blue solution changes the color to yellow. Directions are provided for preparing the bromthymol blue solution. (JR)

  2. Blue nightshade poisoning

    MedlinePlus

    ... when someone eats parts of the blue nightshade plant. This article is for information only. DO NOT ... is found in the blue nightshade ( Solanum dulcamara ) plant, especially in the fruit and leaves.

  3. Gospel and Blues Improvisation.

    ERIC Educational Resources Information Center

    Smallwood, Richard

    1980-01-01

    The similarities and differences between blues and gospel music are identified and the author suggests that both blues and gospel music have inherent improvisational qualities. Methods of capitalizing on these qualities are presented. Selected readings and recordings are included. (KC)

  4. Blue nightshade poisoning

    MedlinePlus

    Blue nightshade poisoning occurs when someone eats parts of the blue nightshade plant. This article is for information only. DO NOT use it to treat or manage an actual poison exposure. If you or someone you ...

  5. Thiamin requirement of Nile tilapia (Oreochromis niloticus)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Juvenile Nile tilapia were fed to apparent satiation twice daily with purified diets containing 0, 1.0, 2.0, 4.0, 8.0 and 16.0 mg/kg and 0. 2.0, 4.0, 8.0, 16.0 and 32.0 mg/kg of thiamin in separate 14-week (experiment 1) and 8-week trials (experiment 2), respectively. Fish fed the diet devoid of thi...

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

    NASA Astrophysics Data System (ADS)

    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 (<100 years) climate-related changes in flooding regime. The CPDF plot of dated floodplain units is interpreted as a record of over-bank river flows, whilst the CPDF plot of palaeochannel units reflect periods of major flooding associated with channel abandonment and contraction, as well as transitions to multi-centennial length episodes of greater aridity and low river flow. This analysis has identified major changes in river flow and dynamics in the Nile catchment with phases of channel and floodplain contraction at c. 6150-5750, 4400-4150, 3700-3450, 2700-2250, 1350-900, 800-550 cal. BC and cal. AD 1600, timeframes that mark shifts to new hydrological and geomorphological regimes. We discuss the impacts of these changing hydromorphological regimes upon riverine civilizations in the Nile Valley.

  7. Phylogenetic Analysis of West Nile Virus, Nuevo Leon State, Mexico

    PubMed Central

    Blitvich, Bradley J.; Fernández-Salas, Ildefonso; Contreras-Cordero, Juan F.; Loroño-Pino, María A.; Marlenee, Nicole L.; Díaz, Francisco J.; González-Rojas, José I.; Obregón-Martínez, Nelson; Chiu-García, Jorge A.; Black, William C.

    2004-01-01

    West Nile virus RNA was detected in brain tissue from a horse that died in June 2003 in Nuevo Leon State, Mexico. Nucleotide sequencing and phylogenetic analysis of the premembrane and envelope genes showed that the virus was most closely related to West Nile virus isolates collected in Texas in 2002. PMID:15324558

  8. Nile behaviour and Upper Palaeolithic humans in Upper Egypt

    NASA Astrophysics Data System (ADS)

    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

  9. Tracking Nile Delta Vulnerability to Holocene Change

    PubMed Central

    Marriner, Nick; Flaux, Clément; Morhange, Christophe; Stanley, Jean-Daniel

    2013-01-01

    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. PMID:23922692

  10. Seroprevalence of West Nile virus in Iran.

    PubMed

    Chinikar, Sadegh; Shah-Hosseini, Nariman; Mostafavi, Ehsan; Moradi, Maryam; Khakifirouz, Sahar; Jalali, Tahmineh; Goya, Mohammad Mehdi; Shirzadi, Mohammad Reza; Zainali, Mohammad; Fooks, Anthony R

    2013-08-01

    This study was undertaken to determine the seroprevalence of West Nile virus (WNV) in human and equine sera in Iran. Blood samples were tested from 300 human samples and 315 equine samples in five geographic zones of north and central parts of Iran between 2010 and 2012. All samples were tested for the immunoglobulin G (IgG) antibody to WNV by using an enzyme-linked immunosorbent assay (ELISA). Of all samples, 4 (1.3%) human and 9 (2.8%) equines were considered to be seropositive for WNV. These results suggest circulation and exposure of the human and equine populations to WNV in Iran. PMID:23697768

  11. Skin manifestations of West Nile virus infection.

    PubMed

    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

  12. Experimental infection of North American birds with the New York 1999 strain of West Nile virus.

    PubMed

    Komar, Nicholas; Langevin, Stanley; Hinten, Steven; Nemeth, Nicole; Edwards, Eric; Hettler, Danielle; Davis, Brent; Bowen, Richard; Bunning, Michel

    2003-03-01

    To evaluate transmission dynamics, we exposed 25 bird species to West Nile virus (WNV) by infectious mosquito bite. We monitored viremia titers, clinical outcome, WNV shedding (cloacal and oral), seroconversion, virus persistence in organs, and susceptibility to oral and contact transmission. Passeriform and charadriiform birds were more reservoir competent (a derivation of viremia data) than other species tested. The five most competent species were passerines: Blue Jay (Cyanocitta cristata), Common Grackle (Quiscalus quiscula), House Finch (Carpodacus mexicanus), American Crow (Corvus brachyrhynchos), and House Sparrow (Passer domesticus). Death occurred in eight species. Cloacal shedding of WNV was observed in 17 of 24 species, and oral shedding in 12 of 14 species. We observed contact transmission among four species and oral in five species. Persistent WNV infections were found in tissues of 16 surviving birds. Our observations shed light on transmission ecology of WNV and will benefit surveillance and control programs. PMID:12643825

  13. Experimental Infection of North American Birds with the New York 1999 Strain of West Nile Virus

    PubMed Central

    Langevin, Stanley; Hinten, Steven; Nemeth, Nicole; Edwards, Eric; Hettler, Danielle; Davis, Brent; Bowen, Richard; Bunning, Michel

    2003-01-01

    To evaluate transmission dynamics, we exposed 25 bird species to West Nile virus (WNV) by infectious mosquito bite. We monitored viremia titers, clinical outcome, WNV shedding (cloacal and oral), seroconversion, virus persistence in organs, and susceptibility to oral and contact transmission. Passeriform and charadriiform birds were more reservoir competent (a derivation of viremia data) than other species tested. The five most competent species were passerines: Blue Jay (Cyanocitta cristata), Common Grackle (Quiscalus quiscula), House Finch (Carpodacus mexicanus), American Crow (Corvus brachyrhynchos), and House Sparrow (Passer domesticus). Death occurred in eight species. Cloacal shedding of WNV was observed in 17 of 24 species, and oral shedding in 12 of 14 species. We observed contact transmission among four species and oral in five species. Persistent WNV infections were found in tissues of 16 surviving birds. Our observations shed light on transmission ecology of WNV and will benefit surveillance and control programs. PMID:12643825

  14. In Vitro and In Vivo Blood-Brain Barrier Models to Study West Nile Virus Pathogenesis.

    PubMed

    Kumar, Mukesh; Nerurkar, Vivek R

    2016-01-01

    The blood-brain barrier (BBB), a specialized interface between the peripheral blood circulation and the central nervous system, specifically regulates molecular and cellular flux between the two. It plays a critical role in the maintenance of brain hemostasis. The BBB restricts the entry of pathogens into the brain, and thus its permeability is a critical factor that determines their central effects. Once the permeability of BBB is compromised, it has serious implications in the etiology of many brain pathologies including West Nile virus (WNV) disease. In this chapter, we describe protocols for preparation, maintenance, infection and permeability measurement of monolayer and bilayer in vitro BBB models to study WNV pathogenesis. We also describe Evans blue dye assay, a well-established method to test vascular permeability in vivo after WNV infection. PMID:27188553

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

    PubMed Central

    Megahed, Ayman Mohamed; Dahshan, Hesham; Abd-El-Kader, Mahdy A.; Abd-Elall, Amr Mohamed Mohamed; Elbana, Mariam Hassan; Nabawy, Ehab; 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 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. PMID:26798844

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

    PubMed

    Megahed, Ayman Mohamed; Dahshan, Hesham; Abd-El-Kader, Mahdy A; Abd-Elall, Amr Mohamed Mohamed; Elbana, Mariam Hassan; Nabawy, Ehab; 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 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. PMID:26798844

  17. Nile Delta vegetation response to Holocene climate variability

    USGS Publications Warehouse

    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.

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

    NASA Astrophysics Data System (ADS)

    Goor, Q.; Halleux, C.; Mohamed, Y.; Tilmant, A.

    2010-10-01

    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. Moreover, the

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

    NASA Astrophysics Data System (ADS)

    Goor, Q.; Halleux, C.; Mohamed, Y.; Tilmant, A.

    2010-07-01

    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. Moreover, the

  20. Templated blue phases.

    PubMed

    Ravnik, Miha; Fukuda, Jun-ichi

    2015-11-21

    Cholesteric blue phases of a chiral liquid crystal are interesting examples of self-organised three-dimensional nanostructures formed by soft matter. Recently it was demonstrated that a polymer matrix introduced by photopolymerization inside a bulk blue phase not only stabilises the host blue phase significantly, but also serves as a template for blue phase ordering. We show with numerical modelling that the transfer of the orientational order of the blue phase to the surfaces of the polymer matrix, together with the resulting surface anchoring, can account for the templating behaviour of the polymer matrix inducing the blue phase ordering of an achiral nematic liquid crystal. Furthermore, tailoring the anchoring conditions of the polymer matrix surfaces can bring about orientational ordering different from those of bulk blue phases, including an intertwined complex of the polymer matrix and topological line defects of orientational order. Optical Kerr response of templated blue phases is explored, finding large Kerr constants in the range of K = 2-10 × 10(-9) m V(-2) and notable dependence on the surface anchoring strength. More generally, the presented numerical approach is aimed to clarify the role and actions of templating polymer matrices in complex chiral nematic fluids, and further to help design novel template-based materials from chiral liquid crystals. PMID:26412643

  1. Blue Willow Story Plates

    ERIC Educational Resources Information Center

    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.

  2. Introducing the Blues.

    ERIC Educational Resources Information Center

    Sinclair, Bryan

    2000-01-01

    Discusses the history of the blues and presents a list of resources that are designed to introduce the blues, both as a feeling and as an influential part of American music and culture. Includes picture books and nonfiction for young readers, nonfiction for older readers, Web sites, and compact disks. (LRW)

  3. Paraphimosis and amputation in a Nile crocodile (Crocodylus niloticus).

    PubMed

    Lankester, Felix; Hernandez-Divers, Stephen J

    2005-12-01

    A captive Nile crocodile (Crocodylus niloticus) developed recurrent episodes of paraphimosis over a 2-yr period, which eventually led to hemorrhage and obvious inflammation. Two months postsurgery, the crocodile remained clinically normal. PMID:17312729

  4. Blue ocean strategy.

    PubMed

    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

  5. West Nile Virus Infection of Birds, Mexico

    PubMed Central

    Guerrero-Sánchez, Sergio; Cuevas-Romero, Sandra; Nemeth, Nicole M.; Trujillo-Olivera, María Teresa Jesús; Worwa, Gabriella; Dupuis, Alan; Brault, Aaron C.; Kramer, Laura D.; Komar, Nicholas

    2011-01-01

    West Nile virus (WNV) has caused disease in humans, equids, and birds at lower frequency in Mexico than in the United States. We hypothesized that the seemingly reduced virulence in Mexico was caused by attenuation of the Tabasco strain from southeastern Mexico, resulting in lower viremia than that caused by the Tecate strain from the more northern location of Baja California. During 2006–2008, we tested this hypothesis in candidate avian amplifying hosts: domestic chickens, rock pigeons, house sparrows, great-tailed grackles, and clay-colored thrushes. Only great-tailed grackles and house sparrows were competent amplifying hosts for both strains, and deaths occurred in each species. Tecate strain viremia levels were higher for thrushes. Both strains produced low-level viremia in pigeons and chickens. Our results suggest that certain avian hosts within Mexico are competent for efficient amplification of both northern and southern WNV strains and that both strains likely contribute to bird deaths. PMID:22172633

  6. Systems analysis of West Nile virus infection.

    PubMed

    Suthar, Mehul S; Pulendran, Bali

    2014-06-01

    Emerging and re-emerging mosquito-borne viruses continue to pose a significant threat to human health throughout the world. Over the past decade, West Nile virus (WNV), Dengue virus (DENV), and Chikungunya virus (CHIKV), have caused annual epidemics of virus-induced encephalitis, hemorrhagic fever\\shock syndromes, and arthritis, respectively. Currently, no specific antiviral therapies or vaccines exist for use in humans to combat or prevent these viral infections. Thus, there is a pressing need to define the virus-host interactions that govern immunity and infection outcome. Recent technological breakthroughs in 'omics' resources and high-throughput based assays are beginning to accelerate antiviral drug discovery and improve on current strategies for vaccine design. In this review, we highlight studies with WNV and discuss how traditional and systems biological approaches are being used to rapidly identify novel host targets for therapeutic intervention and develop a deeper conceptual understanding of the host response to virus infection. PMID:24851811

  7. Mongolian blue spots

    MedlinePlus

    ... bruises. This can raise a question about possible child abuse. It is important to recognize that Mongolian blue ... Elsevier Saunders; 2011:chap 11. Read More Benign Child abuse - physical Rashes Update Date 4/14/2015 Updated ...

  8. Blue Ribbon Panel Report

    Cancer.gov

    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.

  9. Methylene blue unresponsive methemoglobinemia

    PubMed Central

    Patnaik, Sibabratta; Natarajan, Manivachagan Muthappa; James, Ebor Jacob; Ebenezer, Kala

    2014-01-01

    Acquired methemoglobinemia is an uncommon blood disorder induced by exposure to certain oxidizing agents and drugs. Although parents may not give any history of toxin ingestion; with the aid of pulse-oximetry and blood gas analysis, we can diagnose methemoglobinemia. Prompt recognition of this condition is required in emergency situations to institute early methylene blue therapy. We report an unusual case of severe toxic methemoglobinemia, which did not respond to methylene blue, but was successfully managed with exchange transfusion. PMID:24872659

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

    NASA Astrophysics Data System (ADS)

    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.

  11. Impact of the Sudd wetland on the Nile hydroclimatology

    NASA Astrophysics Data System (ADS)

    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.

  12. Impact of the Sudd wetland on the Nile hydroclimatology

    NASA Astrophysics Data System (ADS)

    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.

  13. West Nile Virus Ecology in a Tropical Ecosystem in Guatemala

    PubMed Central

    Morales-Betoulle, Maria E.; Komar, Nicholas; Panella, Nicholas A.; Alvarez, Danilo; López, María R.; Betoulle, Jean-Luc; Sosa, Silvia M.; Müller, María L.; Kilpatrick, A. Marm; Lanciotti, Robert S.; Johnson, Barbara W.; Powers, Ann M.; Cordón-Rosales, Celia

    2013-01-01

    West Nile virus ecology has yet to be rigorously investigated in the Caribbean Basin. We identified a transmission focus in Puerto Barrios, Guatemala, and established systematic monitoring of avian abundance and infection, seroconversions in domestic poultry, and viral infections in mosquitoes. West Nile virus transmission was detected annually between May and October from 2005 to 2008. High temperature and low rainfall enhanced the probability of chicken seroconversions, which occurred in both urban and rural sites. West Nile virus was isolated from Culex quinquefasciatus and to a lesser extent, from Culex mollis/Culex inflictus, but not from the most abundant Culex mosquito, Culex nigripalpus. A calculation that combined avian abundance, seroprevalence, and vertebrate reservoir competence suggested that great-tailed grackle (Quiscalus mexicanus) is the major amplifying host in this ecosystem. West Nile virus transmission reached moderate levels in sentinel chickens during 2007, but less than that observed during outbreaks of human disease attributed to West Nile virus in the United States. PMID:23149586

  14. Safety of West Nile Virus vaccines in sandhill crane chicks

    USGS Publications Warehouse

    Olsen, G.H.; Miller, K.J.; Docherty, D.E.; Bochsler, V.S.

    2008-01-01

    West Nile virus arrived in North America in 1999 and has spread across the continent in the ensuing years. The virus has proven deadly to a variety of native avian species including sandhill cranes (Grus canadensis). In order to provide safe and efficacious protection for captive and released populations of whooping cranes (G. americana), we have conducted a series of four research projects. The last of these was a study of the effects of two different West Nile virus vaccines on young Florida sandhill crane (G. c. pratensis) chicks and subsequent challenge with the virus. We found that vaccinating crane chicks as early as day 7 post-hatch caused no adverse reactions or noticeable morbidity. We tested both a commercial equine vaccine West Nile - Innovator (Fort Dodge Laboratories, Fort Dodge, Iowa) and a new recombinant DNA vaccine (Centers for Disease Control). We had a 33% mortality in control chicks (n =6) from West Nile virus infection, versus 0% mortality in two groups of vaccinated chicks (n = 12), indicating the two vaccines tested were not only safe but effective in preventing West Nile virus.

  15. Molecular cloning of estrogen receptor alpha of the Nile crocodile.

    PubMed

    Katsu, Yoshinao; Myburgh, Jan; Kohno, Satomi; Swan, Gerry E; Guillette, Louis J; Iguchi, Taisen

    2006-03-01

    Estrogens are essential for normal reproductive activity in female and male vertebrates. In female reptiles, they are essential for ovarian differentiation during a critical developmental stage. To understand the molecular mechanisms of estrogen action in the Nile crocodile (Crocodylus niloticus), we have isolated cDNA encoding the estrogen receptor alpha (ERalpha) from the ovary. Degenerate PCR primers specific to ER were designed and used to amplify Nile crocodile cDNA from the ovary. The full-length Nile crocodile ERalpha cDNA was obtained using 5' and 3' rapid amplification cDNA ends (RACE). The deduced amino acid sequence of the Nile crocodile ERalpha showed high identity to the American alligator ERalpha (98%), caiman ER (98%), lizard ER (82%) and chicken ERalpha (92%), although phylogenetic analysis suggested profound differences in the rate of sequence evolution for vertebrate ER sequences. Expression of ERalpha was observed in the ovary and testis of juvenile Nile crocodiles. These data provide a novel tool allowing future studies examining the regulation and ontogenic expression of ERalpha in crocodiles and expands our knowledge of estrogen receptor evolution. PMID:16455277

  16. Host selection by Culex pipiens mosquitoes and West Nile virus amplification.

    PubMed

    Hamer, Gabriel L; Kitron, Uriel D; Goldberg, Tony L; Brawn, Jeffrey D; Loss, Scott R; Ruiz, Marilyn O; Hayes, Daniel B; Walker, Edward D

    2009-02-01

    Recent field studies have suggested that the dynamics of West Nile virus (WNV) transmission are influenced strongly by a few key super spreader bird species that function both as primary blood hosts of the vector mosquitoes (in particular Culex pipiens) and as reservoir-competent virus hosts. It has been hypothesized that human cases result from a shift in mosquito feeding from these key bird species to humans after abundance of the key birds species decreases. To test this paradigm, we performed a mosquito blood meal analysis integrating host-feeding patterns of Cx. pipiens, the principal vector of WNV in the eastern United States north of the latitude 36 degrees N and other mosquito species with robust measures of host availability, to determine host selection in a WNV-endemic area of suburban Chicago, Illinois, during 2005-2007. Results showed that Cx. pipiens fed predominantly (83%) on birds with a high diversity of species used as hosts (25 species). American robins (Turdus migratorius) were marginally overused and several species were underused on the basis of relative abundance measures, including the common grackle (Quiscalus quiscula), house sparrow (Passer domesticus), and European starling (Sturnus vulgaris). Culex pipiens also fed substantially on mammals (19%; 7 species with humans representing 16%). West Nile virus transmission intensified in July of both years at times when American robins were heavily fed upon, and then decreased when robin abundance decreased, after which other birds species were selected as hosts. There was no shift in feeding from birds to mammals coincident with emergence of human cases. Rather, bird feeding predominated when the onset of the human cases occurred. Measures of host abundance and competence and Cx. pipiens feeding preference were combined to estimate the amplification fractions of the different bird species. Predictions were that approximately 66% of WNV-infectious Cx. pipiens became infected from feeding on just

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

    NASA Astrophysics Data System (ADS)

    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

  18. West Nile Virus Encephalitis 16 Years Later.

    PubMed

    Kleinschmidt-DeMasters, Bette K; Beckham, J David

    2015-09-01

    Arboviruses (Arthropod-borne viruses) include several families of viruses (Flaviviridae, Togaviradae, Bunyaviradae, Reoviradae) that are spread by arthropod vectors, most commonly mosquitoes, ticks and sandflies. The RNA genome allows these viruses to rapidly adapt to ever-changing host and environmental conditions. Thus, these virus families are largely responsible for the recent expansion in geographic range of emerging viruses including West Nile virus (WNV), dengue virus and Chikungunya virus. This review will focus on WNV, especially as it has progressively spread westward in North America since its introduction in New York in 1999. By 2003, WNV infections in humans had reached almost all lower 48 contiguous United States (US) and since that time, fluctuations in outbreaks have occurred. Cases decreased between 2008 and 2011, followed by a dramatic flair in 2012, with the epicenter in the Dallas-Fort Worth region of Texas. The 2012 outbreak was associated with an increase in reported neuroinvasive cases. Neuroinvasive disease continues to be a problem particularly in the elderly and immunocompromised populations, although WNV infections also represented the second most frequent cause of pediatric encephalitis in these same years. Neuropathological features in cases from the 2012 epidemic highlight the extent of viral damage that can occur in the CNS. PMID:26276026

  19. West Nile virus: should pediatricians care?

    PubMed

    Smith, Jennifer C; Mailman, Tim; MacDonald, Noni E

    2014-11-01

    Given the recurrent serious outbreaks of West Nile Virus (WNV) in the United States over the past decade, the spread to Canada and South America, the recurrent outbreaks in Europe, and the potential for serious neurological disease even in children under 18 years, paediatricians in affected areas must consider WNV in the differential diagnosis of all children presenting with aseptic meningitis, encephalitis and acute flaccid paralysis. Additionally, given that WNV encephalitis can occur after WNV infection, suspicion for neurological WNV disease must remain high even after otherwise benign febrile illnesses if the child lives in or has traveled to an affected region. Under-diagnosis in the pediatric population is likely a serious problem, necessitating further educational efforts. More follow-up studies of WNV neurological disease in children and youth are needed to better understand the potential long-term sequelae during vulnerable times of neurodevelopment and neural remodeling. Similarly, more research is need on short and long-term fetal outcomes of maternal WNV infection. PMID:25138381

  20. [West Nile virus: a new challenge?].

    PubMed

    Valero, Nereida

    2003-09-01

    West Nile Virus (WNV), a member of the family Flaviviridae, was first isolated in 1937. Since the original isolation of the WNV outbreaks have occurred with increase in frequency of cases in humans and horses, apparent increase in severe human disease and high avian death rates. In 1999, 2000 and 2002 outbreaks of the WNV encephalitis were reported in horses, birds and humans from New York and Canada. Ornithophilic mosquitoes are the principal vectors of the WNV and birds of several species chiefly migrants appear to be the major introductory or amplifying host. The pattern of outbreaks in the old and new world suggests that viremic migratory birds may also contribute to movement of the virus. If so, Central America, Caribbean Islands and countries of South America including Venezuela, are in potential risk for suffering a severe outbreak for WNV, since several species of birds have populations that pass trough New York and cross the western north Atlantic or Caribbean Sea. It is important the knowledge of the ecology of WNV as well of the efficacy of control efforts in order to minimize the public health impact in these countries, where all population is susceptible to this infection. PMID:14552056

  1. West Nile viral infection of equids

    PubMed Central

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

    2015-01-01

    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 strategy for prevention of equine disease is proper vaccination with one of the numerous commercially available vaccines available in North America or the European Union. Recently, WNV has been increasingly associated with equine epizootics resulting from novel non-lineage-1a viruses in expanding geographic areas. However, specific experimental data on the virulence of these novel virus strains is lacking and questions remain as to the etiology of the expanded epizootics: whether it be a function of inherent virulence or ecological and/or climactic factors that could precipitate the altered epidemiological patterns observed. PMID:24035480

  2. Nile delta: recent geological evolution and human impact.

    PubMed

    Stanley, D J; Warne, A G

    1993-04-30

    Few countries in the world are as dependent on water from a single source as Egypt. The natural Nile cycle of flow and sediment discharge has been disrupted by human intervention, including closure of the High Aswan Dam; this intervention has resulted in a series of responses that now threaten the northern Nile delta. Erosion, salinization, and pollution are inducing a marked decline in agricultural productivity and loss of land and coastal lagoons at a time when the population is expanding exponentially. Geological analyses of radiocarbon-dated cores across the northern delta are used to interpret the interaction of sea-level changes, climatic oscillations, subsidence, and transport processes during the past 35,000 years. Recognition of long-term trends of these natural factors provides a basis to evaluate the profound impact of human activity and to assess future changes in the Nile delta ecosystem. PMID:17812219

  3. A Review of Vaccine Approaches for West Nile Virus

    PubMed Central

    Iyer, Arun V.; Kousoulas, Konstantin G.

    2013-01-01

    The West Nile virus (WNC) first appeared in North America in 1999. The North American lineages of WNV were characterized by the presence of neuroinvasive and neurovirulent strains causing disease and death in humans, birds and horses. The 2012 WNV season in the United States saw a massive spike in the number of neuroinvasive cases and deaths similar to what was seen in the 2002–2003 season, according to the West Nile virus disease cases and deaths reported to the CDC by year and clinical presentation, 1999–2012, by ArboNET (Arboviral Diseases Branch, Centers for Disease Control and Prevention). In addition, the establishment and recent spread of lineage II WNV virus strains into Western Europe and the presence of neurovirulent and neuroinvasive strains among them is a cause of major concern. This review discusses the advances in the development of vaccines and biologicals to combat human and veterinary West Nile disease. PMID:24025396

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

    NASA Astrophysics Data System (ADS)

    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

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

    PubMed

    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. Heliacal rising of Sirius and flooding of the Nile

    NASA Astrophysics Data System (ADS)

    Nickiforov, M. G.; Petrova, A. A.

    In this paper the question of prediction of the Nile flood based on the first morning visibility of Sirius is considered. It is shown that the only text that describes this event is formulated very vaguely. It makes impossible to derive a reliable astronomical dating. Modern interpretations of this text are based on the free interpretation of the original source, and often do not match. According to historical evidence of Greek authors and later Egyptian texts, flooding of the Nile based on heliacal rising of Sirius could be predicted at the beginning of I millennium AD. This fact is confirmed by astronomical calculations.

  7. Blue honeysuckle list 47

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This manuscript summarizes descriptions for two newly released Lonicera caerulea L., blue honeysuckle, cultivars released for northern production. This fruit is popular in Russia and in Japan, particularly Hokkaido. It has possibility as a new fruit cultivar for North America. The University of Sask...

  8. Associations between two mosquito populations and West Nile virus in Harris County, Texas, 2003-06.

    PubMed

    Dennett, James A; Bala, Adilelkhidir; Wuithiranyagool, Taweesak; Randle, Yvonne; Sargent, Christopher B; Guzman, Hilda; Siirin, Marina; Hassan, Hassan K; Reyna-Nava, Martin; Unnasch, Thomas R; Tesh, Robert B; Parsons, Ray E; Bueno, Rudy

    2007-09-01

    Associations between Culex quinquefasciatus, Aedes albopictus and West Nile virus (WNV) activity, temperature, and rainfall in Harris County, Texas 2003-06 are discussed. Human cases were highly correlated to Cx. quinquefasciatus (r = 0.87) and Ae. albopictus (r = 0.78) pools, blue jays (r = 0.83), and Ae. albopictus collected (r = 0.71), but not Cx. quinquefasciatus collected (r = 0.45). Human cases were associated with temperature (r = 0.71), not rainfall (r = 0.29), whereas temperature correlated with Ae. albopictus and Cx. quinquefasciatus collections (r = 0.88 and 0.70, respectively) and Cx. quinqueftsciatus pools (r = 0.75), but not Ae. albopictus pools (r = 0.55). Both species (collections and pools) and blue jays were weakly correlated (r 5 0.41) with rainfall, but blue jays were better correlated with Cx. quinquefasciatus pools (r = 0.87), compared with Ae. albopictus pools (r = 0.67), Ae. albopictus collections (r = 0.69), and Cx. quinquefasciatus collections (r = 0.46). Peak minimum infection rate for Cx. quinquefasciatus (4.55), and Ae. albopictus (4.41) was in August with highest human cases (17.87), blue jays (55.58), and temperature (29.01 degrees C). Between both species, blood meal analysis indicated 68.18% of Cx. quinquefasciatus mammalian hosts were dog, while 22.72% were human, whereas Ae. albopictus had higher human (44.44%) but fewer dog hosts (22.22%). Ten bird species were identified as hosts for Cx. quinquefasciatus, with northern cardinal and blue jay representing 26.66% and 20.00%, respectively. No bird feeding activity was observed in Ae. albopictus. The earliest and latest human blood meal occurred in May (Ae. albopictus) and November (Cx. quinquefasciatus); 66.66% of human host identifications between both species occurred in October-November, after the seasonal human case peak. Based upon our data, WNV activity in both mosquito species warrants further investigation of their individual roles in WNV ecology within this region. PMID

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

    NASA Technical Reports Server (NTRS)

    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

  10. Switchable nile red-based probe for cholesterol and lipid order at the outer leaflet of biomembranes.

    PubMed

    Kucherak, Oleksandr A; Oncul, Sule; Darwich, Zeinab; Yushchenko, Dmytro A; Arntz, Youri; Didier, Pascal; Mély, Yves; Klymchenko, Andrey S

    2010-04-01

    Cholesterol and sphingomyelin form together a highly ordered membrane phase, which is believed to play important biological functions in plasma membranes of mammalian cells. Since sphingomyelin is present mainly at the outer leaflet of cell membranes, monitoring its lipid order requires molecular probes capable to bind specifically at this leaflet and exhibit negligibly slow flip-flop. In the present work, such a probe was developed by modifying the solvatochromic fluorescent dye Nile Red with an amphiphilic anchor group. To evaluate the flip-flop of the obtained probe (NR12S), we developed a methodology of reversible redox switching of its fluorescence at one leaflet using sodium dithionite. This method shows that NR12S, in contrast to parent Nile Red, binds exclusively the outer membrane leaflet of model lipid vesicles and living cells with negligible flip-flop in the time scale of hours. Moreover, the emission maximum of NR12S in model vesicles exhibits a significant blue shift in liquid ordered phase (sphingomyelin-cholesterol) as compared to liquid disordered phase (unsaturated phospholipids). As a consequence, these two phases could be clearly distinguished in NR12S-stained giant vesicles by fluorescence microscopy imaging of intensity ratio between the blue and red parts of the probe emission spectrum. Being added to living cells, NR12S binds predominantly, if not exclusively, their plasma membranes and shows an emission spectrum intermediate between those in liquid ordered and disordered phases of model membranes. Importantly, the emission color of NR12S correlates well with the cholesterol content in cell membranes, which allows monitoring the cholesterol depletion process with methyl-beta-cyclodextrin by fluorescence spectroscopy and microscopy. The attractive photophysical and switching properties of NR12S, together with its selective outer leaflet staining and sensitivity to cholesterol and lipid order, make it a new powerful tool for studying model and

  11. STS-56 Earth observation of the northeastern Nile Delta

    NASA Technical Reports Server (NTRS)

    1993-01-01

    STS-56 Earth observation of the northeastern Nile Delta was photographed from the Earth-orbiting Discovery, Orbiter Vehicle (OV) 103. The branch of the Nile featured in the frame is Daimietta. The Suez Canal marks the boundary of the Nile Delta agriculture and the Sinai Desert to the right. Lake Masada, the dark waterlogged area to the west (left) of Port Said is becoming more saline as the Aswan Dam has reduced sediment downstream. This sediment reduction, according to NASA scientists studying the STS-56 photography, has resulted in increased coastal erosion and the intrusion of a salt-water lens to the ground water, particularly in the northeastern portions of the delta. Center pivot irrigation fields are located along either side of the Ramses Canal, which connects the Daimietta Nile with Great Bitter Lake. This canal has been re-dug three or four times in the past 3,000 years. Historians note that the canal's most famous use was as the departure point of the fleet of Pharaoh Necho.

  12. Corvidae feather pulp and West Nile virus detection

    USGS Publications Warehouse

    Docherty, D.E.; Romaine Long, R.; Griffin, Katie M.; Saito, E.K.

    2004-01-01

    We evaluated cloacal swab, vascular pulp of flight feather, and kidney and spleen pool samples from carcasses of members of the family Corvidae as sources of West Nile virus (WNV). The cloacal swab, kidney and spleen pool, and feather pulp were the source of WNV in 38%, 43%, and 77%, respectively, of the carcasses.

  13. Agricultural Model for the Nile Basin Decision Support System

    NASA Astrophysics Data System (ADS)

    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.

  14. Assays to Detect West Nile Virus in Dead Birds

    PubMed Central

    Therrien, Joseph E.; Benson, Robert; Kramer, Laura; Kauffman, Elizabeth B.; Eidson, Millicent; Campbell, Scott

    2005-01-01

    Using oral swab samples to detect West Nile virus in dead birds, we compared the Rapid Analyte Measurement Platform (RAMP) assay with VecTest and real-time reverse-transcriptase–polymerase chain reaction. The sensitivities of RAMP and VecTest for testing corvid species were 91.0% and 82.1%, respectively. PMID:16318736

  15. Antibody Prevalence of West Nile Virus in Birds, Illinois, 2002

    PubMed Central

    Blitvich, Bradley J.; Koo, Hyun-Young; Van de Wyngaerde, Marshall; Brawn, Jeff D.; Novak, Robert J.

    2004-01-01

    Antibodies to West Nile virus were detected in 94 of 1,784 Illinois birds during 2002. Captive and urban birds had higher seropositivity than did birds from natural areas, and northern and central Illinois birds’ seropositivity was greater than that from birds from the southern sites. Adult and hatch-year exposure rates did not differ significantly. PMID:15207067

  16. West Nile Virus Isolation from Equines in Argentina, 2006

    PubMed Central

    Barrandeguy, María; Fabbri, Cintia; Garcia, Jorge B.; Vissani, Aldana; Trono, Karina; Gutierrez, Gerónimo; Pigretti, Santiago; Menchaca, Hernán; Garrido, Nelson; Taylor, Nora; Fernandez, Fernando; Levis, Silvana; Enría, Delia

    2006-01-01

    West Nile virus (WNV) was isolated from the brains of 3 horses that died from encephalitis in February 2006. The horses were from different farms in central Argentina and had not traveled outside the country. This is the first isolation of WNV in South America. PMID:17176571

  17. Warm-blooded isochore structure in Nile crocodile and turtle.

    PubMed

    Hughes, S; Zelus, D; Mouchiroud, D

    1999-11-01

    The genomes of warm-blooded vertebrates are characterized by a strong heterogeneity in base composition, with GC-rich and GC-poor isochores. The GC content of sequences, especially in third codon positions, is highly correlated with that of the isochore they are embedded in. In amphibian and fish genomes, GC-rich isochores are nearly absent. Thus, it has been proposed that the GC increase in a part of mammalian and avian genomes represents an adaptation to homeothermy. To test this selective hypothesis, we sequenced marker protein genes in two cold-blooded vertebrates, the Nile crocodile Crocodylus niloticus (10 genes) and the red-eared slider Trachemys scripta elegans (6 genes). The analysis of base composition in third codon position of this original data set shows that the Nile crocodile and the turtle also exhibit GC-rich isochores, which rules out the homeothermy hypothesis. Instead, we propose that the GC increase results from a mutational bias that took place earlier than the adaptation to homeothermy in birds and before the turtle/crocodile divergence. Surprisingly, the isochore structure appears very similar between the red-eared slider and the Nile crocodile than between the chicken and the Nile crocodile. This point questions the phylogenetic position of turtles as a basal lineage of extant reptiles. We also observed a regular molecular clock in the Archosauria, which enables us, by using a more extended data set, to confirm Kumar and Hedges's dating of the bird-crocodile split. PMID:10555283

  18. Fatal West Nile Virus Encephalitis in a Heart Transplant Recipient

    PubMed Central

    Gomez, Adam J.; Waggoner, Jesse J.; Itoh, Megumi; Hollander, Seth A.; Gutierrez, Kathleen M.; Budvytiene, Indre; Banaei, Niaz

    2015-01-01

    The diagnosis of encephalitis is particularly challenging in immunocompromised patients. We report here a case of fatal West Nile virus encephalitis confounded by the presence of budding yeast in the cerebrospinal fluid (CSF) from a patient who had undergone heart transplantation for dilated cardiomyopathy 11 months prior to presentation of neurologic symptoms. PMID:25994169

  19. Domestic goose model for West Nile virus vaccine efficiency testing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    West Nile virus (WNV) is an emergent pathogen in the Americas, first reported in New York during 1999, and has since spread across the United States (USA), Central and South America causing neurological disease in humans, horses and some bird species, including domestic geese. No WNV vaccines are li...

  20. Is Solar Variability Reflected in the Nile River?

    NASA Technical Reports Server (NTRS)

    Ruzmaikin, Alexander; Feynman, Joan; Yung, Yuk L.

    2006-01-01

    We investigate the possibility that solar variability influences North African climate by using annual records of the water level of the Nile collected in 622-1470 A.D. The time series of these records are nonstationary, in that the amplitudes and frequencies of the quasi-periodic variations are time-dependent. We apply the Empirical Mode Decomposition technique especially designed to deal with such time series. We identify two characteristic timescales in the records that may be linked to solar variability: a period of about 88 years and one exceeding 200 years. We show that these timescales are present in the number of auroras reported per decade in the Northern Hemisphere at the same time. The 11-year cycle is seen in the Nile's high-water level variations, but it is damped in the low-water anomalies. We suggest a possible physical link between solar variability and the low-frequency variations of the Nile water level. This link involves the influence of solar variability on the atmospheric Northern Annual Mode and on its North Atlantic Ocean and Indian Ocean patterns that affect the rainfall over the sources of the Nile in eastern equatorial Africa.

  1. West Nile virus infection in killer whale, Texas, USA, 2007.

    PubMed

    St Leger, Judy; Wu, Guang; Anderson, Mark; Dalton, Les; Nilson, Erika; Wang, David

    2011-08-01

    In 2007, nonsuppurative encephalitis was identified in a killer whale at a Texas, USA, marine park. Panviral DNA microarray of brain tissue suggested West Nile virus (WNV); WNV was confirmed by reverse transcription PCR and sequencing. Immunohistochemistry demonstrated WNV antigen within neurons. WNV should be considered in cases of encephalitis in cetaceans. PMID:21801643

  2. West Nile Virus Infection among the Homeless, Houston, Texas1

    PubMed Central

    Meyer, Tamra E.; Bull, Lara M.; Holmes, Kelly Cain; Pascua, Rhia F.; Travassos da Rosa, Amelia; Gutierrez, Christian R.; Corbin, Tracie; Woodward, Jennifer L.; Taylor, Jeffrey P.; Tesh, Robert B.

    2007-01-01

    Among 397 homeless participants studied, the overall West Nile virus (WNV) seroprevalence was 6.8%. Risk factors for WNV infection included being homeless >1 year, spending >6 hours outside daily, regularly taking mosquito precautions, and current marijuana use. Public health interventions need to be directed toward this high-risk population. PMID:18257995

  3. West Nile virus antibody prevalence in wild mammals, southern Wisconsin

    USGS Publications Warehouse

    Docherty, D.E.; Samuel, M.D.; Nolden, C.A.; Egstad, Kristina F.; Griffin, K.M.

    2006-01-01

    Twenty percent prevalence of West Nile virus antibody was found in free-ranging medium-sized Wisconsin mammals. No significant differences were noted in antibody prevalence with regard to sex, age, month of collection, or species. Our results suggest a similar route of infection in these mammals.

  4. West Nile Virus Fitness Costs in Different Mosquito Species.

    PubMed

    Coffey, Lark L; Reisen, William K

    2016-06-01

    West Nile virus (WNV) remains an important public health problem causing annual epidemics in the United States. Grubaugh et al. observed that WNV genetic divergence is dependent on the vector mosquito species. This suggests that specific WNV vector-bird species pairings may generate novel genotypes that could promote outbreaks. PMID:27108207

  5. West Nile Virus Isolation in Human and Mosquitoes, Mexico

    PubMed Central

    Elizondo-Quiroga, Darwin; Davis, C. Todd; Fernandez-Salas, Ildefonso; Escobar-Lopez, Roman; Olmos, Dolores Velasco; Gastalum, Lourdes Cecilia Soto; Acosta, Magaly Aviles; Elizondo-Quiroga, Armando; Gonzalez-Rojas, Jose I.; Cordero, Juan F. Contreras; Guzman, Hilda; Travassos da Rosa, Amelia; Blitvich, Bradley J.; Barrett, Alan D.T.; Beaty, Barry J.

    2005-01-01

    West Nile virus has been isolated for the first time in Mexico, from a sick person and from mosquitoes (Culex quinquefasciatus). Partial sequencing and analysis of the 2 isolates indicate that they are genetically similar to other recent isolates from northern Mexico and the western United States. PMID:16229779

  6. West Nile Virus Encephalitis in a Barbary Macaque (Macaca sylvanus)

    PubMed Central

    Barker, Ian K.; Crawshaw, Graham J.; Bertelsen, Mads F.; Drebot, Michael A.; Andonova, Maya

    2004-01-01

    An aged Barbary ape (Macaca sylvanus) at the Toronto Zoo became infected with naturally acquired West Nile virus (WNV) encephalitis that caused neurologic signs, which, associated with other medical problems, led to euthanasia. The diagnosis was based on immunohistochemical assay of brain lesions, reverse transcriptase–polymerase chain reaction, and virus isolation. PMID:15200866

  7. The Blue Emu

    NASA Technical Reports Server (NTRS)

    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.

  8. Prostatic blue nevus.

    PubMed

    Anderco, Denisa; Lazăr, Elena; Tăban, Sorina; Miclea, Fl; Dema, Alis

    2010-01-01

    We report the case of a 69-year-old patient with no significant personal urological history. The clinical and ultrasound examination revealed a prostatic gland with increased volume and homogenous appearance. After transurethral resection, multiples gray-brown-blackish prostatic chips were obtained, which could be confused with a malignant melanoma. The histological routine examination in conjunction with the histochemical (Fontana-Masson) and immunohistochemical (S100, HMB45) reactions established the diagnosis of prostatic blue nevus. The presence of melanin in prostatic tissue is an unusual aspect, being encountered three distinct lesions: blue nevus, melanosis and malignant melanoma. Recognition and correct classification of each of these three entities is fundamental, concerning the clinical and prognosis implications. PMID:20809037

  9. Voyager 1 'Blue Movie'

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This is the original Voyager 'Blue Movie' (so named because it was built from Blue filter images). It records the approach of Voyager 1 during a period of over 60 Jupiter days. Notice the difference in speed and direction of the various zones of the atmosphere. The interaction of the atmospheric clouds and storms shows how dynamic the Jovian atmosphere is.

    As Voyager 1 approached Jupiter in 1979, it took images of the planet at regular intervals. This sequence is made from 66 images taken once every Jupiter rotation period (about 10 hours). This time-lapse movie uses images taken every time Jupiter longitude 68W passed under the spacecraft. These images were acquired in the Blue filter from Jan. 6 to Feb. 3 1979. The spacecraft flew from 58 million kilometers to 31 million kilometers from Jupiter during that time.

    This time-lapse movie was produced at JPL by the Image Processing Laboratory in 1979.

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

    NASA Astrophysics Data System (ADS)

    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

  11. VecTest as diagnostic and surveillance tool for West Nile virus in dead birds.

    PubMed

    Stone, Ward B; Okoniewski, Joseph C; Therrien, Joseph E; Kramer, Laura D; Kauffman, Elizabeth B; Eidson, Millicent

    2004-12-01

    The VecTest antigen-capture assay for West Nile virus was performed on oral and tissue swabs from dead birds in New York State from April 2003 through July 2004. Results were compared with those from real-time reverse transcriptase-polymerase chain reaction of kidney or brain. Oral VecTest sensitivity is adequate for surveillance in American Crows (Corvus brachyrhynchos) (87%), Blue Jays (Cyanocitta cristata) (80%), and House Sparrows (Passer domesticus) (76%). Oral VecTest performed well for small samples of American Kestrels (Falco sparverius), Northern Cardinals (Cardinalis cardinalis), Common Grackles (Quiscalus quiscula), and House Finches (Carpodacus mexicanus). Poor sensitivity occurred in most raptors, Mourning Doves (Zenaida macroura), Fish Crows (Corvus ossifragus), and American Robins (Turdus migratorius). Specificity was excellent (98%), except for false-positive results that occurred mostly in Gray Catbirds (Dumatella carolinensis), Green Herons (Butorides virescens), and tests of blood and tissues. Feather pulp and kidney may be useful for VecTest assays in corvids. PMID:15663856

  12. VecTest as Diagnostic and Surveillance Tool for West Nile Virus in Dead Birds

    PubMed Central

    Okoniewski, Joseph C.; Therrien, Joseph E.; Kramer, Laura D.; Kauffman, Elizabeth B.; Eidson, Millicent

    2004-01-01

    The VecTest antigen-capture assay for West Nile virus was performed on oral and tissue swabs from dead birds in New York State from April 2003 through July 2004. Results were compared with those from real-time reverse transcriptase–polymerase chain reaction of kidney or brain. Oral VecTest sensitivity is adequate for surveillance in American Crows (Corvus brachyrhynchos) (87%), Blue Jays (Cyanocitta cristata) (80%), and House Sparrows (Passer domesticus) (76%). Oral VecTest performed well for small samples of American Kestrels (Falco sparverius), Northern Cardinals (Cardinalis cardinalis), Common Grackles (Quiscalus quiscula), and House Finches (Carpodacus mexicanus). Poor sensitivity occurred in most raptors, Mourning Doves (Zenaida macroura), Fish Crows (Corvus ossifragus), and American Robins (Turdus migratorius). Specificity was excellent (98%), except for false-positive results that occurred mostly in Gray Catbirds (Dumatella carolinensis), Green Herons (Butorides virescens), and tests of blood and tissues. Feather pulp and kidney may be useful for VecTest assays in corvids. PMID:15663856

  13. The Blue Marble

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This spectacular Moderate Resolution Imaging Spectroradiometer (MODIS) 'blue marble' image is based on the most detailed collection of true-color imagery of the entire Earth to date. Using a collection of satellite-based observations, scientists and visualizers stitched together months of observations of the land surface, oceans, sea ice, and clouds into a seamless, true-color mosaic of every square kilometer (.386 square mile) of our planet. Most of the information contained in this image came from MODIS, illustrating MODIS' outstanding capacity to act as an integrated tool for observing a variety of terrestrial, oceanic, and atmospheric features of the Earth. The land and coastal ocean portions of this image is based on surface observations collected from June through September 2001 and combined, or composited, every eight days to compensate for clouds that might block the satellite's view on any single day. Global ocean color (or chlorophyll) data was used to simulate the ocean surface. MODIS doesn't measure 3-D features of the Earth, so the surface observations were draped over topographic data provided by the U.S. Geological Survey EROS Data Center. MODIS observations of polar sea ice were combined with observations of Antarctica made by the National Oceanic and Atmospheric Administration's AVHRR sensor-the Advanced Very High Resolution Radiometer. The cloud image is a composite of two days of MODIS imagery collected in visible light wavelengths and a third day of thermal infra-red imagery over the poles. A large collection of imagery based on the blue marble in a variety of sizes and formats, including animations and the full (1 km) resolution imagery, is available at the Blue Marble page. Image by Reto Stockli, Render by Robert Simmon. Based on data from the MODIS Science Team

  14. Blue ocean leadership.

    PubMed

    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

  15. Blue emitting undecaplatinum clusters

    NASA Astrophysics Data System (ADS)

    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

  16. Clinical Manifestations and Outcomes of West Nile Virus Infection

    PubMed Central

    Sejvar, James J.

    2014-01-01

    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. PMID:24509812

  17. Recent progress in West Nile virus diagnosis and vaccination

    PubMed Central

    2012-01-01

    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. PMID:22380523

  18. Monitoring the urbanization of the Nile Delta, Egypt.

    SciTech Connect

    Sultan, M.; Fiske, M.; Stein, T.; Gamal, M.; El Araby, H.; Madani, A.; Mehanee, S.; Becker, R.; Environmental Research; Washington Univ.; Cairo Univ. Center for Environmental Hazard Mitigation

    1999-11-01

    Comparisons of satellite images of the Nile Delta, acquired in 1972, 1984 and 1990, indicate that urban growth is endangering Egypt's agricultural productivity. Urban areas occupied a minimum of 3.6%, 4.7% and 5.7% of the Delta in 1972, 1984 and 1990, respectively, an increase of 58% in 18 years. Approximately half of this increase occurred between 1984 and 1990. If this trend continues, Egypt could lose 12% of its total agricultural area to urbanization by 2010. Despite the fact that growth is pronounced around the cities, it is the growth around the thousands of small villages that poses the largest threat to the agricultural productivity of the Nile Delta. The cumulative growth rate for the cities and large villages between 1972 and 1990 is 37%, and that for the small villages is 77% for the same time period.

  19. Alexander the Great and West Nile Virus Encephalitis

    PubMed Central

    Marr, John S.

    2003-01-01

    Alexander the Great died in Babylon in 323 BC. His death at age 32 followed a 2-week febrile illness. Speculated causes of death have included poisoning, assassination, and a number of infectious diseases. One incident, mentioned by Plutarch but not considered by previous investigators, may shed light on the cause of Alexander’s death. The incident, which occurred as he entered Babylon, involved a flock of ravens exhibiting unusual behavior and subsequently dying at his feet. The inexplicable behavior of ravens is reminiscent of avian illness and death weeks before the first human cases of West Nile virus infection were identified in the United States. We posit that Alexander may have died of West Nile encephalitis. PMID:14725285

  20. A Security Guard With West Nile Virus Encephalitis.

    PubMed

    Smith, Letha

    2016-01-01

    A 57-year-old male working as a security supervisor in an office building was seen for return to work by the on-site occupational health nurse. He was observed to have slow gait as he entered the clinic waiting area, was pale, diaphoretic, and slow in responding to questions. His return to work note stated he was recovering from West Nile Virus (WNV). Implications for return to work are presented. PMID:26245464

  1. Propagation and Titration of West Nile Virus on Vero Cells.

    PubMed

    McAuley, Alexander J; Beasley, David W C

    2016-01-01

    The propagation and titration of viruses are key virological techniques. Unlike other flaviviruses, such as the dengue viruses, West Nile virus (WNV) grows and plaques very efficiently on Vero cells, usually inducing strong cytopathic effect (CPE) and forming clear plaques. Here, we outline the steps for propagating WNV from culture supernatant stocks and homogenized organ/mosquito samples, as well as for determining virus titers in samples by serial-dilution plaque assay using neutral red or crystal violet stains. PMID:27188547

  2. Nile River, Lake Nasser, Aswan High Dam, Egypt, Africa

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Lake Nasser, (24.0N, 33.0E) at the Aswan High Dam on the Nile River, in Egypt is the world's second largest artificial lake, extending 500 km, in length and about 5000 sq. km. in area. The lake has a storage capacity sufficient to irrigate farms in Egypt and Sudan year round allowing up to three harvests per year. Other benefits include year round river navagation, hydroelectric power, more fish harvests, reduced flooding and more industrial employment. opportunites.

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

    NASA Astrophysics Data System (ADS)

    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.

  4. Ecology of West Nile Virus in North America

    PubMed Central

    Reisen, William K.

    2013-01-01

    The introduction, dispersal and establishment of West Nile virus in North America were reviewed, focusing on factors that may have enhanced receptivity and enabled the invasion process. The overwintering persistence of this tropical virus within temperate latitudes was unexpected, but was key in the transition from invasion to endemic establishment. The cascade of temporal events allowing sporadic amplification to outbreak levels was discussed within a future perspective. PMID:24008376

  5. The Influence of Atmospheric Aerosols on Air Quality Status of the Egyptian Nile Delta

    NASA Astrophysics Data System (ADS)

    El-Askary, H. M.; Zakey, A.

    2014-12-01

    Due to the combination of natural and anthropogenic sources of emission over the Nile Delta region, the air quality status is very poor and has a significant health hazards impacts on the population. Here we focused on the optical and chemical characterizations of atmospheric aerosols in the Nile Delta using the online integrated Environmental-Climate Aerosols model (EnvClimA) during a 10 year period 2000-2010. Observations from MODIS and SeaWiFS measurements supplemented by CALIPSO and some ground-based data from AERONET, are used to validate the EnvClimA model and to illustrate the aerosol characteristics and their sources. CALIPSO measurements were used to characterize the vertical structure of aerosols and their shapes (spherical and non-spherical) for major dust storms and biomass burning events. In this study we discussed the synoptic patterns and features, which are associated with either the dust storm or high pollution events. We used MODIS derived aerosol parameters to study seasonal changes in aerosol parameters due to the influence of dust storms, anthropogenic pollution and biomass (crop residue) burning. MODIS derived deep blue AOD provided better representation of aerosol loading over north Africa (Sahara region) along with dark-target AOD and related parameters. AERONET data provided aerosol optical depth, angstrom, fine mode fraction, size fraction, volume, effective radius, refractive index, single scattering albedo, and radiative forcing during different seasons dominated by dust storms, anthropogenic pollution and biomass burning (black cloud phenomena). The results indicated that the observed AOD decreases in the summer and increases again in the fall due to agricultural burning events. Ground-based AERONET data support the "Dark Product" MODIS retrievals, as they typically show a fall peak in the 500 nm region. The number of dust distribution frequencies over Egypt has more frequency in the southeast and northwest of Egypt (5-7.5 days

  6. Transplantation of Adrenal Cortical Progenitor Cells Enriched by Nile Red

    PubMed Central

    Dunn, James C.Y.; Chu, Yinting; Qin, Harry H.; Zupekan, Tatiana

    2009-01-01

    Background The adrenal cortex may contain progenitor cells useful for tissue regeneration. Currently there are no established methods to isolate these cells. Material and Methods Murine adrenal cells were sorted into a Nile-Red-bright (NRbright) and a Nile-Red-dim (NRdim) population of cells according to their degree of cholesterol content revealed by Nile Red fluorescence. The cells were transplanted under the renal capsule to determine their ability for regeneration. Results The NRbright cells contained an abundance of lipid droplets, whereas the NRdim cells contained little. The NRbright cells expressed Sf1 and the more differentiated adrenal cortical genes including Cyp11a1, Cyp11b1, and Cyp11b2, whereas the NRdim cells expressed Sf1 but not the more differentiated adrenal cortical genes. After 56 days of implantation in unilateral adrenalectomized mice, the NRdim cells expressed Sf1 and the more differentiated adrenal cortical genes, whereas the NRbright cells ceased to express Sf1 as well as the more differentiated adrenal cortical genes. NRdim cells also proliferated in the presence of basic fibroblast growth factor. Conclusions The population of NRdim cells contained adrenal cortical progenitor cells that can proliferate and give rise to differentiated daughter cells. These cells may be useful for adrenal cortical regeneration. PMID:19592014

  7. Lack of detection of West Nile virus in an islander population of chelonians during a West Nile virus outbreak.

    PubMed

    Di Girolamo, Nicola; Selleri, Paolo; Di Gennaro, Annapia; Maldera, Marco; Nardini, Giordano; Morandi, Benedetto; Muzzeddu, Marco; Origgi, Francesco; Savini, Giovanni

    2016-06-30

    In 2011, several outbreaks of West Nile disease occurred in Sardinia (Italy). The region hosts several chelonian species. Because of the increasing concern on the potential role that ectotherms may play in the ecology of West Nile virus (WNV), in October 2011 blood samples were collected from 41 endemic Sardinian chelonians and tested for the presence of active WNV infection or neutralizing antibodies by real time polymerase chain reaction (RT-PCR) and serumneutralisation, respectively. Neither WNV neutralising antibodies (0%; 95% CI: 0‑8.4%) nor WNV RNA (0%; 95% CI: 0‑6.8%) were found in the tested samples. According to the results of this screening survey, it is unlikely that chelonians are involved in the epidemiology of the 2011 WNV outbreaks in Sardinia. PMID:27393879

  8. Wetland vegetation in Manzala lagoon, Nile Delta coast, Egypt: Rapid responses of pollen to altered nile hydrology and land use

    USGS Publications Warehouse

    Bernhardt, C.E.; Stanley, J.-D.; Horton, B.P.

    2011-01-01

    The pollen record in a sediment core from Manzala lagoon on the Nile delta coastal margin of Egypt, deposited from ca. AD 1860 to 1990, indicates rapid coastal wetland vegetation responses to two primary periods of human activity. These are associated with artificially altered Nile hydrologic regimes in proximal areas and distal sectors located to ???1200 km south of Manzala. Freshwater wetland plants that were dominant, such as Typha and Phragmites, decreased rapidly, whereas in the early 1900s, brackish water wetland species (e.g., Amaranthaceae) increased. This change occurred after closure of the Aswan Low Dam in 1902. The second major modification in the pollen record occurred in the early 1970s, after Aswan High Dam closure from 1965 to 1970, when Typha pollen abundance increased rapidly. Massive population growth occurred along the Nile during the 130 years represented by the core section. During this time, the total volume of lagoon water decreased because of conversion of wetland areas to agricultural land, and input of organic-rich sediment, sewage (municipal, agricultural, industrial), and fertilizer in Manzala lagoon increased markedly. Although the wetland plant community has continued to respond to increasingly intensified and varied human-induced pressures in proximal sectors, the two most marked changes in Manzala pollen best correlate with distal events (i.e., closure of the two dams at Aswan). The study also shows that the two major vegetation changes in Manzala lagoon each occurred less than 10 years after closure upriver of the Low and High dams that markedly altered the Nile regime from Upper Egypt to the coast. ?? 2011, the Coastal Education & Research Foundation (CERF).

  9. Pluto’s Blue Haze

    NASA Video Gallery

    The sky on Pluto is blue! Kind of. This is Pluto in an Minute. So it’s not exactly the case that the sky on Pluto is blue, rather, what the New Horizons science team has found in recent images do...

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

    PubMed Central

    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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  12. 78 FR 16505 - Prospective Grant of Exclusive License: Chimeric West Nile/Dengue Viruses

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-15

    ...: Chimeric West Nile/Dengue Viruses AGENCY: Centers for Disease Control and Prevention (CDC), Department of... license, in the field of use of in vitro diagnostics for dengue virus infection, to practice the... Application 61/049,342, filed 4/30/2008, entitled ``Engineered, Chimeric West Nile/Dengue Viruses;''...

  13. Comparison of Immunohistochemistry and Virus Isolation for Diagnosis of West Nile Virus

    PubMed Central

    Ellis, Angela E.; Mead, Daniel G.; Allison, Andrew B.; Gibbs, Samantha E. J.; Gottdenker, Nicole L.; Stallknecht, David E.; Howerth, Elizabeth W.

    2005-01-01

    Immunohistochemistry and virus isolation were performed on 1,057 birds. Immunohistochemistry, virus isolation, or both found 325 birds to be West Nile virus positive. Of these, 271 were positive by both methods. These results indicate that virus isolation and immunohistochemistry are approximately equal in their ability to detect West Nile virus. PMID:15956415

  14. Explaining and Forecasting Interannual Variability in the Flow of the Nile River

    NASA Astrophysics Data System (ADS)

    Eltahir, E. A.; Siam, M.

    2013-12-01

    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. 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 (60oE-90oE and 25oS-35oS) 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 indices of the SST in the Eastern Pacific and Southern Indian Oceans.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

    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

  17. Lake Nasser on Nile River in Egypt as seen from the Apollo 7 spacecraft

    NASA Technical Reports Server (NTRS)

    1968-01-01

    Lake Nasser on the Nile River in southeastern United Arab Republic (Egypt) as seen from the Apollo 7 spacecraft during its 10th revolution of the earth. Photographed from an altitude of 130 nautical miles, at ground elapsed time of 14 hours and 56 minutes. Lake Nasser was created by the contruction of the Aswan Dam on the Nile.

  18. Identification and expression profiles of multiple genes in Nile tilapia in response to bacterial infections

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To understand the molecular mechanisms involved in response of Nile tilapia (Oreochromis niloticus) to bacterial infection, suppression subtractive cDNA hybridization technique was used to identify upregulated genes in the posterior kidney of Nile tilapia at 6h post infection with Aeromonas hydrophi...

  19. A GIS Tool To Estimate West Nile Virus Risk based On A Degree-Day Model

    Technology Transfer Automated Retrieval System (TEKTRAN)

    West Nile virus(Flaviviridae: Flavivirus) is a serious infectious disease that recently spread across the North America continent. A spatial analysis tool was developed on the ARCMap 9.x platform to estimate potential West Nile virus activitiy using a spatially explicit degree-day model. The mdoel...

  20. Blue ellipticals in compact groups

    NASA Technical Reports Server (NTRS)

    Zepf, Stephen E.; Whitmore, Bradley C.

    1990-01-01

    By studying galaxies in compact groups, the authors examine the hypothesis that mergers of spiral galaxies make elliptical galaxies. The authors combine dynamical models of the merger-rich compact group environment with stellar evolution models and predict that roughly 15 percent of compact group ellipticals should be 0.15 mag bluer in B - R color than normal ellipticals. The published colors of these galaxies suggest the existence of this predicted blue population, but a normal distribution with large random errors can not be ruled out based on these data alone. However, the authors have new ultraviolet blue visual data which confirm the blue color of the two ellipticals with blue B - R colors for which they have their own colors. This confirmation of a population of blue ellipticals indicates that interactions are occurring in compact groups, but a blue color in one index alone does not require that these ellipticals are recent products of the merger of two spirals. The authors demonstrate how optical spectroscopy in the blue may distinguish between a true spiral + spiral merger and the swallowing of a gas-rich system by an already formed elliptical. The authors also show that the sum of the luminosity of the galaxies in each group is consistent with the hypothesis that the final stage in the evolution of compact group is an elliptical galaxy.

  1. Blue moons and Martian sunsets.

    PubMed

    Ehlers, Kurt; Chakrabarty, Rajan; Moosmüller, Hans

    2014-03-20

    The familiar yellow or orange disks of the moon and sun, especially when they are low in the sky, and brilliant red sunsets are a result of the selective extinction (scattering plus absorption) of blue light by atmospheric gas molecules and small aerosols, a phenomenon explainable using the Rayleigh scattering approximation. On rare occasions, dust or smoke aerosols can cause the extinction of red light to exceed that for blue, resulting in the disks of the sun and moon to appear as blue. Unlike Earth, the atmosphere of Mars is dominated by micron-size dust aerosols, and the sky during sunset takes on a bluish glow. Here we investigate the role of dust aerosols in the blue Martian sunsets and the occasional blue moons and suns on Earth. We use the Mie theory and the Debye series to calculate the wavelength-dependent optical properties of dust aerosols most commonly found on Mars. Our findings show that while wavelength selective extinction can cause the sun's disk to appear blue, the color of the glow surrounding the sun as observed from Mars is due to the dominance of near-forward scattering of blue light by dust particles and cannot be explained by a simple, Rayleigh-like selective extinction explanation. PMID:24663457

  2. Neuropsychological Impact of West Nile Virus Infection: An Extensive Neuropsychiatric Assessment of 49 Cases in Canada

    PubMed Central

    Samaan, Zainab; McDermid Vaz, Stephanie; Bawor, Monica; Potter, Tammy Hlywka; Eskandarian, Sasha; Loeb, Mark

    2016-01-01

    Background West Nile virus emerged as an important human pathogen in North America and continues to pose a risk to public health. It can cause a highly variable range of clinical manifestations ranging from asymptomatic to severe illness. Neuroinvasive disease due to West Nile virus can lead to long-term neurological deficits and psychological impairment. However, these deficits have not been well described. The objective of this study was to characterize the neuropsychological manifestations of West Nile virus infection with a focus on neuroinvasive status and time since infection. Methods Patients from Ontario Canada with a diagnosis of neuroinvasive disease (meningitis, encephalitis, or acute flaccid paralysis) and non-neuroinvasive disease who had participated in a cohort study were enrolled. Clinical and laboratory were collected, as well as demographics and medical history. Cognitive functioning was assessed using a comprehensive battery of neuropsychological tests. Results Data from 49 individuals (32 with West Nile fever and 17 with West Nile neuroinvasive disease) were included in the present cross-sectional analysis. Patterns of neuropsychological impairment were comparable across participants with both neuroinvasive and non-neuroinvasive West Nile virus infection on all cognitive measures. Neuropsychiatric impairment was also observed more frequently at two to four years post-infection compared to earlier stages of illness. Conclusions Our data provide objective evidence for cognitive difficulties among patients who were infected with West Nile virus; these deficits appear to manifest regardless of severity of West Nile virus infection (West Nile fever vs. West Nile neuroinvasive disease), and are more prevalent with increasing illness duration (2–4 years vs. 1 month). Data from this study will help inform patients and healthcare providers about the expected course of recovery, as well as the need to implement effective treatment strategies that

  3. Blue upconversion thulium laser

    SciTech Connect

    Nguyen, D.C.; Faulkner, G.E.; Weber, M.E.; Dulick, M.

    1990-01-01

    Upconversion has been an active area of research for at least two decades, mainly because of its wide ranging applications from infrared quantum counters, visible-emitting phosphors, to upconversion lasers. The upconversion lasers have recently become attractive with the advent of semiconductor laser diodes as the pump source. In an upconversion laser, the laser active ion is excited by internal upconversion of near-ir or red light via multiphoton excitation or cooperative processes and emits anti-Stokes visible light. Since the laser diode output wavelength can be composition turned to match the upconversion laser ion absorption lines, a substantial fraction of the ions can be driven into higher energy levels, thus enhancing the upconversion process. These upconversion solid-state lasers offer a potentially simple and compact source of visible coherent light with semiconductor laser diode excitation. We recently reported a novel upconversion thulium laser that emits blue light at 77 K. In this paper additional data on this 77 K upconversion laser as well as preliminary results on the room temperature upconversion laser are presented. In these demonstrations, dye lasers were used instead of diode lasers because they were more readily available than high power semiconductor laser diodes and their wavelengths could be adjusted easily. 14 refs., 5 figs., 1 tab.

  4. Blue metal complex pigments involved in blue flower color

    PubMed Central

    Takeda, Kosaku

    2006-01-01

    The blue pigment of cornflower, protocyanin, has been investigated for a long time, but its precise structure was not entirely explained until recently. The molecular structure of the pigment was recently shown to be a metal complex of six molecules each of anthocyanin and flavone glycoside, with one ferric iron, one magnesium and two calcium ions by X-ray crystallographic analysis. The studies provided the answer to the question posed in the early part of the last century, “why is the cornflower blue and rose red when both flowers contain the same anthocyanin?” This work was achieved on the basis of the results of long years of the studies made by many researchers. In this review, the author focuses on the investigations of the blue metal complex pigments involved in the bluing of flowers, commelinin from Commelina commusis, protocyanin from Centaurea cyanus, protodelphin from Salvia patens and hydrangea blue pigment. PMID:25792777

  5. Hazards of solar blue light

    SciTech Connect

    Okuno, Tsutomu

    2008-06-01

    Short-wavelength visible light (blue light) of the Sun has caused retinal damage in people who have stared fixedly at the Sun without adequate protection. The author quantified the blue-light hazard of the Sun according to the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines by measuring the spectral radiance of the Sun. The results showed that the exposure limit for blue light can be easily exceeded when people view the Sun and that the solar blue-light hazard generally increases with solar elevation, which is in accordance with a model of the atmospheric extinction of sunlight. Viewing the Sun can be very hazardous and therefore should be avoided except at very low solar elevations.

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

    PubMed

    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

  7. West Nile Virus Infection in the Central Nervous System

    PubMed Central

    Winkelmann, Evandro R.; Luo, Huanle; Wang, Tian

    2016-01-01

    West Nile virus (WNV), a neurotropic single-stranded flavivirus has been the leading cause of arboviral encephalitis worldwide.  Up to 50% of WNV convalescent patients in the United States were reported to have long-term neurological sequelae.  Neither antiviral drugs nor vaccines are available for humans.  Animal models have been used to investigate WNV pathogenesis and host immune response in humans.  In this review, we will discuss recent findings from studies in animal models of WNV infection, and provide new insights on WNV pathogenesis and WNV-induced host immunity in the central nervous system. PMID:26918172

  8. Nile River, Lake Nasser, Aswan High Dam, Egypt

    NASA Technical Reports Server (NTRS)

    1992-01-01

    The Aswan High Dam, 2.5 miles across and 364 feet high, (24.0N, 33.0E) completed in 1971, was constructed to supply cheap hydroelectric power to both Egypt and Sudan by impounding, controling and regulating the flood waters of the Nile River in Lake Nasser, the world's second largest artifical lake. The lake extends over 500 miles in length, covers an area of some 2,000 square miles and is as much as 350 feet deep at the face of the dam.

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

    PubMed

    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. PMID:26790946

  10. West Nile Virus in Europe and Safety of Blood Transfusion

    PubMed Central

    Pisani, Giulio; Cristiano, Karen; Pupella, Simonetta; Liumbruno, Giancarlo Maria

    2016-01-01

    Summary West Nile virus (WNV) has become an increasing issue in the transfusion setting since 2002, when it was firstly shown in the USA that it can be transmitted through blood transfusion. Since then, several precautionary measures have been introduced in Europe in order to reduce the possible risk of transmission via transfusion/solid organ transplantation. In addition, the epidemiological surveillance has been tightened and the network for communication of human WNV cases strengthened. This review will focus on WNV circulation and the safety of blood in Europe. PMID:27403087

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

    USGS Publications Warehouse

    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.

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

    PubMed Central

    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

  13. Amyloid fibrillogenesis of lysozyme is suppressed by a food additive brilliant blue FCF.

    PubMed

    Chen, Yu-Han; Tseng, Chia-Ping; How, Su-Chun; Lo, Chun-Hsien; Chou, Wei-Lung; Wang, Steven S-S

    2016-06-01

    At least 30 different human proteins can fold abnormally to form the amyloid deposits that are associated with a number of degenerative diseases. The research presented here aimed at understanding the inhibitory potency of a food additive, brilliant blue FCF (BBF), on the amyloid fibril formation of lysozyme. Our results demonstrated that BBF was able to suppress the formation of lysozyme fibrils in a dose-dependent fashion. In addition, the structural features and conformational changes in the lysozyme samples upon the addition of BBF were further characterized using circular dichroism spectroscopy, nile red fluorescence spectroscopy, turbidity assay, and sodium dodecyl sulfate electrophoresis. Through molecular docking and molecular dynamics simulations, BBF's mechanism of action in lysozyme fibrillogenesis inhibition was found to be initiated by binding with the aggregation-prone region of the lysozyme. We believe the results from this research may contribute to the development of effective therapeutics for amyloidoses. PMID:26970823

  14. Kupffer cell structure in the juvenile Nile crocodile, Crocodylus niloticus.

    PubMed

    van Wilpe, Erna; Groenewald, Hermanus Bernardus

    2014-01-01

    The morphology of Kupffer cells was examined in the liver of the juvenile Nile crocodile using light microscopy and transmission electron microscopy. Pleomorphic Kupffer cells were located in the sinusoids, in the space of Disse, in the hepatic parenchyma and often connected adjacent sinusoids. The cell surfaces were irregular due to the presence of filopodia and lamelliapodia with phagocytosis of white blood cells, red blood cells and thrombocytes being evident. The cells were in close contact with endothelial cells and pit cells in the sinusoidal lumen and with stellate cells in the space of Disse. The cytoplasm contained large phagosomes comprising a combination of ceroid pigment, melanosomes and siderosomes. The nuclei were often indented and eccentrically placed due to the presence of the phagosomes. Conspicuous clusters of membrane-bound tubular organelles with a filamentous or crystalline interior were observed in the cytoplasm. The clusters were sometimes separated into smaller groups around phagosomes. A clear zone existed between the limiting membrane and the interior of these tubular organelles with the electron-dense interior profiles being, respectively, circular, angular or divided. The tubular organelles have not previously been described in Kupffer cells and possibly represent lysosomes with specialized functions. Mitochondria, microtubules, Golgi profiles, granular and smooth endoplasmic reticulum, and a few cytoplasmic lipid droplets were also present. The presence of the tubular organelles and the occurrence of the Kupffer cells in different locations in the liver of the juvenile Nile crocodile are indicative of particularly active and mobile cells. PMID:24142864

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

    USGS Publications Warehouse

    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.

  16. Facies analysis of Nile delta continental shelf sediments off Egypt

    NASA Astrophysics Data System (ADS)

    Frihy, Omran E.; Gamai, Ibrahim H.

    This study evaluates the texture and coarse fraction composition of 108 bottom samples from the Nile delta continental shelf. In total 19 petrological variables were considered for each of the samples, and Q-mode factor analysis of the textural and mineralogical variables yielded 4 factors (facies groups): Facies I. Fine and very fine sands, light minerals, heavy minerals and 'glauconite', extending from the shoreline to the inner shelf and decreasing away from the shoreline. Facies II. Silty sand rich in biogenic components occupies the entire outer shelf and its contiguous lower terraces. Facies III. Mud (silt plus clay), mica and 'glauconite', covering the middle shelf and the upper terraces. Facies IV. Fine to coarse-grained sediments and 'glauconite', locally distributed along the coast off lake ldku, Burullus headland, and Damietta promontory and El Gamil. The configuration patterns of facies I (delta-front), facies III (prodelta) and facies IV (distributary mouth bar or progradational coastal sand) help identify delta lobes related to former distributary branches of the Nile river (Canopic, Saitic, Sebennitic, Atribic and Mendisian). The 4 facies-forming shelf sediments have resulted from sediment dynamics, sea-level fluctuation and differences in sediment input and provenance.

  17. Experimental Infection of Raccoons (Procyon lotor) with West Nile Virus

    PubMed Central

    Root, J. Jeffrey; Bentler, Kevin T.; Nemeth, Nicole M.; Gidlewski, Thomas; Spraker, Terry R.; Franklin, Alan B.

    2010-01-01

    To characterize the responses of raccoons to West Nile virus (WNV) infection, we subcutaneously exposed them to WNV. Moderately high viremia titers (≤ 104.6 plaque forming units [PFU]/mL of serum) were noted in select individuals; however, peak viremia titers were variable and viremia was detectable in some individuals as late as 10 days post-inoculation (DPI). In addition, fecal shedding was prolonged in some animals (e.g., between 6 and 13 DPI in one individual), with up to105.0 PFU/fecal swab detected. West Nile virus was not detected in tissues collected on 10 or 16 DPI, and no histologic lesions attributable to WNV infection were observed. Overall, viremia profiles suggest that raccoons are unlikely to be important WNV amplifying hosts. However, this species may occasionally shed significant quantities of virus in feces. Considering their behavioral ecology, including repeated use of same-site latrines, high levels of fecal shedding could potentially lead to interspecies fecal-oral WNV transmission. PMID:20889868

  18. Epidemiological history and phylogeography of West Nile virus lineage 2.

    PubMed

    Ciccozzi, Massimo; Peletto, Simone; Cella, Eleonora; Giovanetti, Marta; Lai, Alessia; Gabanelli, Elena; Acutis, Pier Luigi; Modesto, Paola; Rezza, Giovanni; Platonov, Alexander E; Lo Presti, Alessandra; Zehender, Gianguglielmo

    2013-07-01

    West Nile virus (WNV) was first isolated in Uganda. In Europe WNV was sporadically detected until 1996, since then the virus has been regularly isolated from birds and mosquitoes and caused several outbreaks in horses and humans. Phylogenetic analysis showed two main different WNV lineages. The lineage 1 is widespread and segregates into different subclades (1a-c). WNV-1a includes numerous strains from Africa, America, and Eurasia. The spatio-temporal history of WNV-1a in Europe was recently described, identifying two main routes of dispersion, one in Eastern and the second in Western Europe. The West Nile lineage 2 (WNV-2) is mainly present in sub-Saharan Africa but has been recently emerged in Eastern and Western European countries. In this study we reconstruct the phylogeny of WNV-2 on a spatio-temporal scale in order to estimate the time of origin and patterns of geographical dispersal of the different isolates, particularly in Europe. Phylogeography findings obtained from E and NS5 gene analyses suggest that there were at least two separate introductions of WNV-2 from the African continent dated back approximately to the year 1999 (Central Europe) and 2000 (Russia), respectively. The epidemiological implications and clinical consequences of lineage 1 and 2 cocirculation deserve further investigations. PMID:23542457

  19. Methylene blue related sterile endophthalmitis.

    PubMed

    Lim, A K E; Ulagantheran V, V; Siow, Y C; Lim, K S

    2008-08-01

    To report a case of methylene blue related endophthalmitis. Observational case report. Review of clinical record, photographs. A 60 year old man developed endophthalmitis after methylene blue was accidentally used to stain the anterior capsule during phacoemulsification of cataract. His left visual acuity deteriorated from 6/12 to 6/36 two weeks after the operation. Despite intensive treatment with topical and intravitreal antibiotics, his condition deteriorated. A vitrectomy and silicone oil injection eventually managed to control the progression of the disease and salvage the eye. However the visual outcome remained poor due to corneal decompensation and retinal ischemia. Both vitreous tap and vitreous biopsy were negative for any organism. Methylene blue is extremely toxic to ocular structures and should not be used intraocularly. PMID:19248701

  20. Migratory birds and spread of West Nile virus in the Western Hemisphere.

    PubMed Central

    Rappole, J. H.; Derrickson, S. R.; Hubálek, Z.

    2000-01-01

    West Nile virus, an Old World flavivirus related to St. Louis encephalitis virus, was first recorded in the New World during August 1999 in the borough of Queens, New York City. Through October 1999, 62 patients, 7 of whom died, had confirmed infections with the virus. Ornithophilic mosquitoes are the principal vectors of West Nile virus in the Old World, and birds of several species, chiefly migrants, appear to be the major introductory or amplifying hosts. If transovarial transmission or survival in overwintering mosquitoes were the principal means for its persistence, West Nile virus might not become established in the New World because of aggressive mosquito suppression campaigns conducted in the New York area. However, the pattern of outbreaks in southern Europe suggests that viremic migratory birds may also contribute to movement of the virus. If so, West Nile virus has the potential to cause outbreaks throughout both temperate and tropical regions of the Western Hemisphere. PMID:10905964

  1. Detection of West Nile virus in mosquitoes by RT-PCR.

    PubMed

    Hadfield, T L; Turell, M; Dempsey, M P; David, J; Park, E J

    2001-06-01

    A reverse transcriptase-polymerase chain reaction (RT-PCR) assay employing detection technology was developed to identify West Nile virus in experimentally infected mosquitoes. The specificity of the assay was evaluated with the following viruses: eastern equine encephalitis, Ilheus, West Nile and yellow fever viruses. The limits of detection were determined using West Nile viral RNA extracted from serial dilutions of virus culture in infected mosquitoes. Limit of detection was 5 PFU from extracted mosquitoes. We were able to detect the presence of one infected mosquito in a pool of 50 repeatedly. When the RT-PCR was used with coded samples of intrathoracically-infected and uninfected mosquitoes, the assay detected the virus in all infected mosquitoes. Analytic sensitivity and specificity were 100%. This assay offers an efficient and rapid method of identifying West Nile virus in infected mosquitoes or cell culture. PMID:11352595

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

    PubMed

    Lovely, C J; Pittman, J M; Leslie, A J

    2007-09-01

    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. PMID:18237036

  3. Enhanced mortality in Nile tilapia, Oreochromis niloticus following coinfections with ichthyophthiriasis and streptococcosis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ichthyophthirius multifiliis Fouquet (Ich) and Streptococcus iniae are two common pathogens of cultured Nile tilapia, Oreochromis niloticus (L). Two trials were conducted to determine whether parasitism in tilapia with Ich increased mortality following immersion infection with S. iniae. Results of...

  4. Protective immunity of Nile tilapia against Ichthyophthirius multifiliis post immunization with live theronts and sonicated trophonts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two immunization trials were conducted to evaluate host protection of Nile tilapia, Oreochromis niloticus against Ichthyophthirius multifiliis (Ich). Immunizations were done with live theronts or sonicated trophonts by bath immersion and intraperitoneal (IP) injection. The immunized fish were challe...

  5. 15. VIEW OF THE ORIGINAL 10TON OVERHEAD NILES TRAVELING CRANE. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. VIEW OF THE ORIGINAL 10-TON OVERHEAD NILES TRAVELING CRANE. - Washington Water Power Company Post Falls Power Plant, Middle Channel Powerhouse & Dam, West of intersection of Spokane & Fourth Streets, Post Falls, Kootenai County, ID

  6. The blue-collar brain.

    PubMed

    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

  7. Blue-green upconversion laser

    DOEpatents

    Nguyen, D.C.; Faulkner, G.E.

    1990-08-14

    A blue-green laser (450--550 nm) uses a host crystal doped with Tm[sup 3+]. The Tm[sup 3+] is excited through upconversion by a red pumping laser and an IR pumping laser to a state which transitions to a relatively lower energy level through emissions in the blue-green band, e.g., 450.20 nm at 75 K. The exciting laser may be tunable dye lasers or may be solid-state semiconductor laser, e.g., GaAlAs and InGaAlP. 3 figs.

  8. Crater Lake: blue through time

    USGS Publications Warehouse

    Larson, Gary L.; Buktenica, Mark; Collier, Robert

    2003-01-01

    Blue is the color of constancy, hence the term true blue. The unearthly blueness of Crater Lake reflects its pristine character and gives scientists a focal point for studying human impacts on aquatic environments over long periods of time. Scientists with the U.S. Geological Survey (USGS), National Park Service, and Oregon State University have systematically studied the lake for the last two decades. Long-term monitoring of this lake is a priority of Crater Lake National Park and will continue far into the future.

  9. The Blue-Collar Brain

    PubMed Central

    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

  10. Blue-green upconversion laser

    DOEpatents

    Nguyen, Dinh C.; Faulkner, George E.

    1990-01-01

    A blue-green laser (450-550 nm) uses a host crystal doped with Tm.sup.3+. The Tm.sup.+ is excited through upconversion by a red pumping laser and an IR pumping laser to a state which transitions to a relatively lower energy level through emissions in the blue-green band, e.g., 450.20 nm at 75 K. The exciting laser may be tunable dye lasers or may be solid-state semiconductor laser, e.g., GaAlAs and InGaAlP.

  11. Blue light emitting thiogallate phosphor

    DOEpatents

    Dye, Robert C.; Smith, David C.; King, Christopher N.; Tuenge, Richard T.

    1998-01-01

    A crystalline blue emitting thiogallate phosphor of the formula RGa.sub.2 S.sub.4 :Ce.sub.x where R is selected from the group consisting of calcium, strontium, barium and zinc, and x is from about 1 to 10 atomic percent, the phosphor characterized as having a crystalline microstructure on the size order of from about 100 .ANG. to about 10,000 .ANG. is provided together with a process of preparing a crystalline blue emitting thiogallate phosphor by depositing on a substrate by CVD and resultant thin film electroluminescent devices including a layer of such deposited phosphor on an ordinary glass substrate.

  12. Production of oocytes of Nile tilapia (Oreochromis niloticus) for in vitro fertilization via hormonal treatments.

    PubMed

    Fernandes, A F A; Alvarenga, É R; Oliveira, D A A; Aleixo, C G; Prado, S A; Luz, R K; Sarmento, N L A F; Teixeira, E A; Luz, M R; Turra, E M

    2013-12-01

    Only a few studies have described hormonal treatments for induction of synchronicity and gamete collection in Nile tilapia (Oreochromis niloticus), both important for assortative matings in breeding programmes and essential for polyploidy technologies. In this study, we compared the effectiveness of carp pituitary extract (CPE), Nile tilapia pituitary extract (TPE), human chorionic gonadotropin (hCG) and gonadotropin-releasing hormone (GnRH) protocols on the induction of spawning and egg production in Nile tilapia. Among the hormonal treatments analysed, only hCG was effective for producing viable gametes for in vitro fertilization. To verify the viability of this hormonal treatment, hCG was tested using different doses (1000, 2000, 3000, 4000 and 5000 IU/kg) in a large number of females (208 animals) from two Nile tilapia lines. The results indicated that hCG doses between 1000 and 5000 IU/kg could be used to induce final oocyte maturation in Nile tilapia with collection of stripped oocytes. This is the first study to report differential reproductive responses to hormonal treatment between tilapia lines: line 1 was more efficient at producing eggs and post-hatching larvae after hCG induction than line 2. In conclusion, we demonstrated that the hCG protocol may be applied on a large scale to induce final oocyte maturation in Nile tilapia. The development of a protocol for in vitro fertilization in Nile tilapia may aid in breeding programmes and biotechnological assays for the development of genetically modified lines of Nile tilapia. PMID:23834584

  13. Human case of West Nile neuroinvasive disease in Portugal, summer 2015.

    PubMed

    Zé-Zé, Líbia; Proença, Paula; Osório, Hugo C; Gomes, Salomé; Luz, Teresa; Parreira, Paulo; Fevereiro, Miguel; Alves, Maria João

    2015-01-01

    A case of West Nile virus (WNV) infection was reported in the Algarve region, Portugal, in the first week of September 2015. WNV is known to circulate in Portugal, with occasional reports in horses and birds (2004 to 2011) and very sporadically human cases (in 2004 and in 2010). Here we present the clinical and laboratory aspects related to the first human case of West Nile neuroinvasive disease reported in Portugal. PMID:26535915

  14. Clinical and pathologic features of West Nile virus infection in native North American owls (Family strigidae).

    PubMed

    Fitzgerald, S D; Patterson, J S; Kiupel, M; Simmons, H A; Grimes, S D; Sarver, C F; Fulton, R M; Steficek, B A; Cooley, T M; Massey, J P; Sikarskie, J G

    2003-01-01

    Since the initial report of West Nile virus in the northeastern United States in 1999, the virus has spread rapidly westward and southward across the country. In the summer of 2002, several midwestern states reported increased cases of neurologic disease and mortality associated with West Nile virus infection in various native North American owl species. This report summarizes the clinical and pathologic findings for 13 captive and free-ranging owls. Affected species were all in the family Strigidae and included seven snowy owls (Nyctea scandiaca), four great-horned owls (Bubo virginianus), a barred owl (Strix varia), and a short-eared owl (Asio flammeus). Neurologic signs identified included head tilt, uncoordinated flight, paralysis, tremors, and seizures. Owls that died were screened for flaviviral proteins by immunohistochemical staining of formalin-fixed tissues, followed by specific polymerase chain reaction assay to confirm West Nile virus with fresh tissues when available. Microscopic lesions were widespread, involving brain, heart, liver, kidney, and spleen, and were typically nonsuppurative with infiltration by predominantly lymphocytes and plasma cells. Lesions in owls were much more severe than those previously reported in corvids such as crows, which are considered highly susceptible to infection and are routinely used as sentinel species for monitoring for the presence and spread of West Nile virus. This report is the first detailed description of the pathology of West Nile virus infection in Strigiformes and indicates that this bird family is susceptible to natural infection with West Nile virus. PMID:14562887

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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. Blue light hazard and aniridia.

    PubMed Central

    Abadi, R. V.; Dickinson, C. M.

    1985-01-01

    The fundi of three patients with aniridia were photographed with a 470 nm illuminating light source. No apparent change in contrast was observable throughout the macular region. This would suggest an absence of the macular pigment. The likelihood of aniridics being more susceptible than normal persons to blue light damage is discussed. Images PMID:3978071

  17. Singing' the Black and Blues

    ERIC Educational Resources Information Center

    Fisher, Diane

    2004-01-01

    It is so obvious that the sky is blue in the daytime and black at night, but it took the smartest humans thousands of years of observation, thought, discussion, conjecture, and analysis to finally come up with answers that make scientific sense as to why the sky is these colors. This article discusses light and the scientific research…

  18. Flying the Blue Ribbon Flag.

    ERIC Educational Resources Information Center

    McDaniel, Lynda

    2000-01-01

    Guntersville Elementary School, a preK-2 school in Alabama, earned the U.S. Department of Education's Blue Ribbon Schools award through creative programs addressing school readiness, parent education, and the need for extended-day and summer activities; a progressive curriculum; and various community partnerships. (SV)

  19. The Taos Blue Lake Ceremony.

    ERIC Educational Resources Information Center

    Bodine, John J.

    1988-01-01

    Describes the Blue Lake Ceremony of the Taos Pueblo Indians of New Mexico. Reproduces the 1906 account of the ceremony by anthropologist Matilda Coxe Stevenson and notes modern verification and change. Discusses the importance of this annual August pilgrimage and initiation rite to the preservation of Taos culture. (SV)

  20. Nobel Prize for blue LEDs

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed

    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

  2. Progress on the Development of Therapeutics against West Nile Virus

    PubMed Central

    Diamond, Michael S

    2009-01-01

    A decade has passed since the appearance of West Nile virus (WNV) in humans in the Western Hemisphere in New York City. During this interval, WNV spread inexorably throughout North and South America and caused millions of infections ranging from a sub-clinical illness, to a self-limiting febrile syndrome or lethal neuroinvasive disease. Its entry into the United States triggered intensive research into the basic biology of WNV and the elements that comprise a protective host immune response. Although no therapy is currently approved for use in humans, several strategies are being pursued to develop effective prophylaxis and treatments. This review describes the current state of knowledge on epidemiology, clinical presentation, pathogenesis, and immunobiology of WNV infection, and highlights progress toward an effective therapy. PMID:19501622

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

    PubMed

    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

  4. The relationships between West Nile and Kunjin viruses.

    PubMed Central

    Scherret, J. H.; Poidinger, M.; Mackenzie, J. S.; Broom, A. K.; Deubel, V.; Lipkin, W. I.; Briese, T.; Gould, E. A.; Hall, R. A.

    2001-01-01

    Until recently, West Nile (WN) and Kunjin (KUN) viruses were classified as distinct types in the Flavivirus genus. However, genetic and antigenic studies on isolates of these two viruses indicate that the relationship between them is more complex. To better define this relationship, we performed sequence analyses on 32 isolates of KUN virus and 28 isolates of WN virus from different geographic areas, including a WN isolate from the recent outbreak in New York. Sequence comparisons showed that the KUN virus isolates from Australia were tightly grouped but that the WN virus isolates exhibited substantial divergence and could be differentiated into four distinct groups. KUN virus isolates from Australia were antigenically homologous and distinct from the WN isolates and a Malaysian KUN virus. Our results suggest that KUN and WN viruses comprise a group of closely related viruses that can be differentiated into subgroups on the basis of genetic and antigenic analyses. PMID:11585535

  5. West Nile virus epizootiology in the southeastern United States, 2001.

    PubMed

    Godsey, Marvin S; Blackmore, Mark S; Panella, Nicholas A; Burkhalter, Kristen; Gottfried, Kristy; Halsey, Lawrence A; Rutledge, Roxanne; Langevin, Stanley A; Gates, Robert; Lamonte, Karen M; Lambert, Amy; Lanciotti, Robert S; Blackmore, Carina G M; Loyless, Tom; Stark, Lillian; Oliveri, Robin; Conti, Lisa; Komar, Nicholas

    2005-01-01

    We investigated mosquito and bird involvement in West Nile virus (WNV) transmission in July 2001 in Jefferson County, FL, and Lowndes County, GA. We detected 16 WNV-infected pools from Culex quinquefasciatus, Cx. salinarius, Cx. nigripalpus, and Culiseta melanura. In Florida, 11% of 353 bird sera neutralized WNV. Antibody prevalence was greatest in northern cardinal (Cardinalis cardinalis, 75%), northern mockingbird (Mimus polyglottus, 50%), common ground-dove (Columbina passerina, 25%), common grackle (Quiscalus quiscula, 15%), domestic chicken (Gallus gallus, 16%), and house sparrow (Passer domesticus, 11%). Antibody-positive birds were detected in nine of 11 locations, among which prevalence in chickens ranged from 0% to 100%. Seropositive chickens were detected in Georgia as well. The primary transmission cycle of WNV in the southeastern United States apparently involves Culex mosquitoes and passerine birds. Chickens are frequently infected and may serve as effective sentinels in this region. PMID:15815153

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

    PubMed Central

    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

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

    PubMed

    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

  8. Ixodid and Argasid Tick Species and West Nile Virus

    PubMed Central

    Uzcátegui, Nathalie Yumari; Gould, Ernest Andrew; Nuttall, Patricia Anne

    2004-01-01

    Control of West Nile virus (WNV) can only be effective if the vectors and reservoirs of the virus are identified and controlled. Although mosquitoes are the primary vectors, WNV has repeatedly been isolated from ticks. Therefore tick-borne transmission studies were performed with an ixodid (Ixodes ricinus) and an argasid tick species (Ornithodoros moubata). Both species became infected after feeding upon viremic hosts, but I. ricinus ticks were unable to maintain the virus. In contrast, O. moubata ticks were infected for at least 132 days, and the infection was maintained through molting and a second bloodmeal. Infected O. moubata ticks transmitted the virus to rodent hosts, albeit at a low level. Moreover, the virus was nonsystemically transmitted between infected and uninfected O. moubata ticks co-fed upon uninfected hosts. Although ticks are unlikely to play a major role in WNV transmission, our findings suggest that some species have the potential to act as reservoirs for the virus. PMID:15200855

  9. The Global Ecology and Epidemiology of West Nile Virus

    PubMed Central

    Rios, Maria

    2015-01-01

    Since its initial isolation in Uganda in 1937 through the present, West Nile virus (WNV) has become an important cause of human and animal disease worldwide. WNV, an enveloped virus of the genus Flavivirus, is naturally maintained in an enzootic cycle between birds and mosquitoes, with occasional epizootic spillover causing disease in humans and horses. The mosquito vectors for WNV are widely distributed worldwide, and the known geographic range of WNV transmission and disease has continued to increase over the past 77 years. While most human infections with WNV are asymptomatic, severe neurological disease may develop resulting in long-term sequelae or death. Surveillance and preventive measures are an ongoing need to reduce the public health impact of WNV in areas with the potential for transmission. PMID:25866777

  10. Avian Hosts of West Nile Virus in Arizona

    PubMed Central

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

    2013-01-01

    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

  11. Reconciling West Nile virus with the autophagic pathway

    PubMed Central

    Martín-Acebes, Miguel A; Blázquez, Ana-Belén; Saiz, Juan-Carlos

    2015-01-01

    West Nile virus (WNV) is a neurotropic mosquito-borne flavivirus responsible for recurrent outbreaks of meningitis and encephalitis. Several studies analyzing the interactions of this pathogen with the autophagic pathway have reported opposite results with evidence for and against the upregulation of autophagy in infected cells. In this regard, we have recently reported that minimal genetic changes (single amino acid substitutions) in nonstructural proteins of WNV can modify the ability of the virus to induce autophagic features such as LC3 modification and aggregation in infected cells. We think that these results could help explain some of the previously reported discrepancies. These findings could also aid in deciphering the interactions of this pathogen with the autophagic pathway at the molecular level aimed to develop feasible antiviral strategies to combat this pathogen, and other related flaviviruses. PMID:25946067

  12. Current Trends in West Nile Virus Vaccine Development

    PubMed Central

    Amanna, Ian J.; Slifka, Mark K.

    2014-01-01

    West Nile virus (WNV) is a mosquito-borne flavivirus that has become endemic in the United States. From 1999-2012, there have been 37,088 reported cases of WNV and 1,549 deaths, resulting in a 4.2% case-fatality rate. Despite development of effective WNV vaccines for horses, there is no vaccine to prevent human WNV infection. Several vaccines have been tested in preclinical studies and to date there have been 8 clinical trials, with promising results in terms of safety and induction of antiviral immunity. Although mass vaccination is unlikely to be cost-effective, implementation of a targeted vaccine program may be feasible if a safe and effective vaccine can be brought to market. Further evaluation of new and advanced vaccine candidates is strongly encouraged. PMID:24689659

  13. Epidemiology and Transmission Dynamics of West Nile Virus Disease

    PubMed Central

    Komar, Nicholas; Nasci, Roger S.; Montgomery, Susan P.; O'Leary, Daniel R.; Campbell, Grant L.

    2005-01-01

    From 1937 until 1999, West Nile virus (WNV) garnered scant medical attention as the cause of febrile illness and sporadic encephalitis in parts of Africa, Asia, and Europe. After the surprising detection of WNV in New York City in 1999, the virus has spread dramatically westward across the United States, southward into Central America and the Caribbean, and northward into Canada, resulting in the largest epidemics of neuroinvasive WNV disease ever reported. From 1999 to 2004, >7,000 neuroinvasive WNV disease cases were reported in the United States. In 2002, WNV transmission through blood transfusion and organ transplantation was described for the first time, intrauterine transmission was first documented, and possible transmission through breastfeeding was reported. This review highlights new information regarding the epidemiology and dynamics of WNV transmission, providing a new platform for further research into preventing and controlling WNV disease. PMID:16102302

  14. Characterization of Virulent West Nile Virus Kunjin Strain, Australia, 2011

    PubMed Central

    Frost, Melinda J.; Zhang, Jing; Edmonds, Judith H.; Prow, Natalie A.; Gu, Xingnian; Davis, Rodney; Hornitzky, Christine; Arzey, Kathleen E.; Finlaison, Deborah; Hick, Paul; Read, Andrew; Hobson-Peters, Jody; May, Fiona J.; Doggett, Stephen L.; Haniotis, John; Russell, Richard C.; Hall, Roy A.; Khromykh, Alexander A.

    2012-01-01

    To determine the cause of an unprecedented outbreak of encephalitis among horses in New South Wales, Australia, in 2011, we performed genomic sequencing of viruses isolated from affected horses and mosquitoes. Results showed that most of the cases were caused by a variant West Nile virus (WNV) strain, WNVNSW2011, that is most closely related to WNV Kunjin (WNVKUN), the indigenous WNV strain in Australia. Studies in mouse models for WNV pathogenesis showed that WNVNSW2011 is substantially more neuroinvasive than the prototype WNVKUN strain. In WNVNSW2011, this apparent increase in virulence over that of the prototype strain correlated with at least 2 known markers of WNV virulence that are not found in WNVKUN. Additional studies are needed to determine the relationship of the WNVNSW2011 strain to currently and previously circulating WNVKUN strains and to confirm the cause of the increased virulence of this emerging WNV strain. PMID:22516173

  15. Megalocytivirus infection in cultured Nile tilapia Oreochromis niloticus.

    PubMed

    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

  16. Experimental Infections of Wild Birds with West Nile Virus

    PubMed Central

    Pérez-Ramírez, Elisa; Llorente, Francisco; Jiménez-Clavero, Miguel Ángel

    2014-01-01

    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. PMID:24531334

  17. Diversification of West Nile virus in a subtropical region

    PubMed Central

    Chisenhall, Daniel M; Mores, Christopher N

    2009-01-01

    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 antigenicity of the homodimer. Taken

  18. Autonomic Nervous Dysfunction in Hamsters Infected with West Nile Virus

    PubMed Central

    Wang, Hong; Siddharthan, Venkatraman; Hall, Jeffery O.; Morrey, John D.

    2011-01-01

    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 hyperplarization-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. PMID:21573009

  19. Environmental predictors of West Nile fever risk in Europe

    PubMed Central

    2014-01-01

    Background West Nile virus (WNV) is a mosquito-borne pathogen of global public health importance. Transmission of WNV is determined by abiotic and biotic factors. The objective of this study was to examine environmental variables as predictors of WNV risk in Europe and neighboring countries, considering the anomalies of remotely sensed water and vegetation indices and of temperature at the locations of West Nile fever (WNF) outbreaks reported in humans between 2002 and 2013. Methods The status of infection by WNV in relationship to environmental and climatic risk factors was analyzed at the district level using logistic regression models. Temperature, remotely sensed Normalized Difference Vegetation Index (NDVI) and Modified Normalized Difference Water Index (MNDWI) anomalies, as well as population, birds’ migratory routes, and presence of wetlands were considered as explanatory variables. Results The anomalies of temperature in July, of MNDWI in early June, the presence of wetlands, the location under migratory routes, and the occurrence of a WNF outbreak the previous year were identified as risk factors. The best statistical model according to the Akaike Information Criterion was used to map WNF risk areas in 2012 and 2013. Model validations showed a good level of prediction: area under Receiver Operator Characteristic curve = 0.854 (95% Confidence Interval 0.850-0.856) for internal validation and 0.819 (95% Confidence Interval 0.814-0.823) (2012) and 0.853 (95% Confidence Interval 0.850-0.855) (2013) for external validations, respectively. Conclusions WNF incidence is increasing in Europe and WNV is expanding into new areas where it had never been observed before. Our model can be used to direct surveillance activities and public health interventions for the upcoming WNF season. PMID:24986363

  20. West Nile virus in Tunisia, 2014: First isolation from mosquitoes.

    PubMed

    Wasfi, F; Dachraoui, K; Cherni, S; Bosworth, A; Barhoumi, W; Dowall, S; Chelbi, I; Derbali, M; Zoghlami, Z; Beier, J C; Zhioua, E

    2016-07-01

    Several outbreaks of human West Nile virus (WNV) infections were reported in Tunisia during the last two decades. Serological studies on humans as well as on equine showed intensive circulation of WNV in Tunisia. However, no virus screening of mosquitoes for WNV has been performed in Tunisia. In the present study, we collected mosquito samples from Central Tunisia to be examined for the presence of flaviviruses. A total of 102 Culex pipiens mosquitoes were collected in September 2014 from Central Tunisia. Mosquitoes were pooled according to the collection site, date and sex with a maximum of 5 specimens per pool and tested for the presence of flaviviruses by conventional reverse transcription heminested PCR and by a specific West Nile virus real time reverse transcription PCR. Of a total of 21 pools tested, 7 were positive for WNV and no other flavivirus could be evidenced in mosquito pools. In addition, WNV was isolated on Vero cells. Phylogenetic analysis showed that recent Tunisian WNV strains belong to lineage 1 WNV and are closely related to the Tunisian strain 1997 (PAH 001). This is the first detection and isolation of WNV from mosquitoes in Tunisia. Some areas of Tunisia are at high risk for human WNV infections. WNV is likely to cause future sporadic and foreseeable outbreaks. Therefore, it is of major epidemiological importance to set up an entomological surveillance as an early alert system. Timely detection of WNV should prompt vector control to prevent future outbreaks. In addition, education of people to protect themselves from mosquito bites is of major epidemiological importance as preventive measure against WNV infection. PMID:27038557

  1. The Blues Poetry of Langston Hughes

    ERIC Educational Resources Information Center

    Waldron, Edward E.

    1971-01-01

    The author discusses the criteria of the blues as an American art form. He then shows how Langston Hughes captures the mood, the feeling, the rhythm and the impact of the blues in his poetry. (Author/LF)

  2. Practical utility of the blue spectral region

    NASA Technical Reports Server (NTRS)

    Ross, D. S.

    1972-01-01

    Some aspects of multispectral photography in the blue region are discussed briefly, and sample images are submitted to demonstrate the potential utility of the blue multispectral record for oceanography.

  3. 21 CFR 73.50 - Ultramarine blue.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... ultramarine blue is a blue pigment obtained by calcining a mixture of kaolin, sulfur, sodium carbonate, and... order to vary the shade. The pigment is a complex sodium aluminum sulfo-silicate having the...

  4. 21 CFR 73.50 - Ultramarine blue.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... ultramarine blue is a blue pigment obtained by calcining a mixture of kaolin, sulfur, sodium carbonate, and... order to vary the shade. The pigment is a complex sodium aluminum sulfo-silicate having the...

  5. 21 CFR 73.50 - Ultramarine blue.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... ultramarine blue is a blue pigment obtained by calcining a mixture of kaolin, sulfur, sodium carbonate, and... order to vary the shade. The pigment is a complex sodium aluminum sulfo-silicate having the...

  6. 21 CFR 73.50 - Ultramarine blue.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... ultramarine blue is a blue pigment obtained by calcining a mixture of kaolin, sulfur, sodium carbonate, and... order to vary the shade. The pigment is a complex sodium aluminum sulfo-silicate having the...

  7. 21 CFR 73.50 - Ultramarine blue.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... ultramarine blue is a blue pigment obtained by calcining a mixture of kaolin, sulfur, sodium carbonate, and... order to vary the shade. The pigment is a complex sodium aluminum sulfo-silicate having the...

  8. On Seeing Reddish Green and Yellowish Blue.

    ERIC Educational Resources Information Center

    Crane, Hewitt D.; Piantanida, Thomas P.

    1983-01-01

    Stabilization of the retinal image of the boundary between a pair of red/green or yellow/blue stripes, but not their outer edges, results in the entire region being perceived simultaneously as both red/green or yellow/blue. This suggests that the percepts of reddish-green/yellowish-blue apparently are possible in corticocortical color vision…

  9. 75 FR 65525 - Anthem Blue Cross Blue Shield, Claim Management Services, Inc. Operations, a Division of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-25

    ... on September 3, 2010 (75 FR 54187). The workers supply claims processing services and customer... Employment and Training Administration Anthem Blue Cross Blue Shield, Claim Management Services, Inc... Adjustment Assistance (TAA), applicable to workers and former workers of Anthem Blue Cross Blue Shield,...

  10. An ancient icon reveals new mysteries: mummy DNA resurrects a cryptic species within the Nile crocodile.

    PubMed

    Hekkala, Evon; Shirley, Matthew H; Amato, George; Austin, James D; Charter, Suellen; Thorbjarnarson, John; Vliet, Kent A; Houck, Marlys L; Desalle, Rob; Blum, Michael J

    2011-10-01

    The Nile crocodile (Crocodylus niloticus) is an ancient icon of both cultural and scientific interest. The species is emblematic of the great civilizations of the Nile River valley and serves as a model for international wildlife conservation. Despite its familiarity, a centuries-long dispute over the taxonomic status of the Nile crocodile remains unresolved. This dispute not only confounds our understanding of the origins and biogeography of the 'true crocodiles' of the crown genus Crocodylus, but also complicates conservation and management of this commercially valuable species. We have taken a total evidence approach involving phylogenetic analysis of mitochondrial and nuclear markers, as well as karyotype analysis of chromosome number and structure, to assess the monophyletic status of the Nile crocodile. Samples were collected from throughout Africa, covering all major bioregions. We also utilized specimens from museum collections, including mummified crocodiles from the ancient Egyptian temples at Thebes and the Grottes de Samoun, to reconstruct the genetic profiles of extirpated populations. Our analyses reveal a cryptic evolutionary lineage within the Nile crocodile that elucidates the biogeographic history of the genus and clarifies long-standing arguments over the species' taxonomic identity and conservation status. An examination of crocodile mummy haplotypes indicates that the cryptic lineage corresponds to an earlier description of C. suchus and suggests that both African Crocodylus lineages historically inhabited the Nile River. Recent survey efforts indicate that C. suchus is declining or extirpated throughout much of its distribution. Without proper recognition of this cryptic species, current sustainable use-based management policies for the Nile crocodile may do more harm than good. PMID:21906195

  11. Status of Blue Ridge Reservoir

    SciTech Connect

    Not Available

    1990-09-01

    This is one in a series of reports prepared by the Tennessee Valley Authority (TVA) for those interested in the conditions of TVA reservoirs. This overview of Blue Ridge Reservoir summarizes reservoir and watershed characteristics, reservoir uses and use impairments, water quality and aquatic biological conditions, and activities of reservoir management agencies. This information was extracted from the most current reports and data available, as well as interview with water resource professionals in various federal, state, and local agencies. Blue Ridge Reservoir is a single-purpose hydropower generating project. When consistent with this primary objective, the reservoir is also operated to benefit secondary objectives including water quality, recreation, fish and aquatic habitat, development of shoreline, aesthetic quality, and other public and private uses that support overall regional economic growth and development. 8 refs., 1 fig.

  12. The Physics of the Blues

    NASA Astrophysics Data System (ADS)

    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.

  13. Food habits of blue grouse

    USGS Publications Warehouse

    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.

  14. Ol' Blue Eyes, in Focus

    ERIC Educational Resources Information Center

    Nelson, Michael

    2009-01-01

    Scholarly books with "identity" and "culture" in the title have loomed large on academic publishing lists for several years. Scholarly books with "Sinatra" in the title are a more recent phenomenon. Despite his six-decade career as the Voice (the 1940s), the Chairman of the Board (the 50s and 60s), and Ol' Blue Eyes (the 70s through his death, in…

  15. Models of Individual Blue Stragglers

    NASA Astrophysics Data System (ADS)

    Sills, Alison

    This chapter describes the current state of models of individual blue stragglers. Stellar collisions, binary mergers (or coalescence), and partial or ongoing mass transfer have all been studied in some detail. The products of stellar collisions retain memory of their parent stars and are not fully mixed. Very high initial rotation rates must be reduced by an unknown process to allow the stars to collapse to the main sequence. The more massive collision products have shorter lifetimes than normal stars of the same mass, while products between low mass stars are long-lived and look very much like normal stars of their mass. Mass transfer can result in a merger, or can produce another binary system with a blue straggler and the remnant of the original primary. The products of binary mass transfer cover a larger portion of the colour-magnitude diagram than collision products for two reasons: there are more possible configurations which produce blue stragglers, and there are differing contributions to the blended light of the system. The effects of rotation may be substantial in both collision and merger products, and could result in significant mixing unless angular momentum is lost shortly after the formation event. Surface abundances may provide ways to distinguish between the formation mechanisms, but care must be taken to model the various mixing mechanisms properly before drawing strong conclusions. Avenues for future work are outlined.

  16. The Cryptochrome Blue Light Receptors.

    PubMed

    Yu, Xuhong; Liu, Hongtao; Klejnot, John; Lin, Chentao

    2010-09-23

    Cryptochromes are photolyase-like blue light receptors originally discovered in Arabidopsis but later found in other plants, microbes, and animals. Arabidopsis has two cryptochromes, CRY1 and CRY2, which mediate primarily blue light inhibition of hypocotyl elongation and photoperiodic control of floral initiation, respectively. In addition, cryptochromes also regulate over a dozen other light responses, including circadian rhythms, tropic growth, stomata opening, guard cell development, root development, bacterial and viral pathogen responses, abiotic stress responses, cell cycles, programmed cell death, apical dominance, fruit and ovule development, seed dormancy, and magnetoreception. Cryptochromes have two domains, the N-terminal PHR (Photolyase-Homologous Region) domain that bind the chromophore FAD (flavin adenine dinucleotide), and the CCE (CRY C-terminal Extension) domain that appears intrinsically unstructured but critical to the function and regulation of cryptochromes. Most cryptochromes accumulate in the nucleus, and they undergo blue light-dependent phosphorylation or ubiquitination. It is hypothesized that photons excite electrons of the flavin molecule, resulting in redox reaction or circular electron shuttle and conformational changes of the photoreceptors. The photoexcited cryptochrome are phosphorylated to adopt an open conformation, which interacts with signaling partner proteins to alter gene expression at both transcriptional and posttranslational levels and consequently the metabolic and developmental programs of plants. PMID:21841916

  17. Uncovering Blue Diffuse Dwarf Galaxies

    NASA Astrophysics Data System (ADS)

    James, Bethan; Koposov, Sergey; Stark, Daniel; Belokurov, Vasily; Pettini, Max; Olszewski, Edward W.

    2015-01-01

    Extremely metal-poor galaxies (XMPs) and the star-formation within their chemically pristine environments are fundamental to our understanding of the galaxy formation process at early times. However, traditional emission-line surveys detect only the brightest metal-poor galaxies where star-formation occurs in compact, starbursting environments, and thereby give us only a partial view of the dwarf galaxy population. To avoid such biases, we have developed a new search algorithm based on the morphological, rather then spectral, properties of XMPs and have applied to the Sloan Digital Sky Survey database of images. Using this novel approach, we have discovered ~100 previously undetected, faint blue galaxies, each with isolated HII regions embedded in a diffuse continuum. In this talk I will present the first results from follow-up optical spectroscopy of this sample, which reveals these blue diffuse dwarfs (BDDs) to be young, very metal-poor and actively forming stars despite their intrinsically low luminosities. I will present evidence showing that BDDs appear to bridge the gap between quiescent dwarf irregular (dIrr) galaxies and blue compact galaxies (BCDs) and as such offer an ideal opportunity to assess how star-formation occurs in more `normal' metal-poor systems.

  18. Localized Eruptive Blue Nevi after Herpes Zoster

    PubMed Central

    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

  19. Inflation and alternatives with blue tensor spectra

    SciTech Connect

    Wang, Yi; Xue, Wei E-mail: wei.xue@sissa.it

    2014-10-01

    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.

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

    PubMed

    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

  1. IMMERSION VACCINATION OF NEWLY HATCHED AND SEX REVERSED NILE TILAPIA (Oreochromis niloticus) USING A STREPTOCOCCUS INIAE VACCINE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this investigation was to assess immersion Streptococcus iniae vaccination of newly hatched and sex reversed Nile tilapia fry against S. iniae. Nile tilapia (Oreochromis niloticus; 0.01 g wet weight; 160,000 fish/1500 L) were immunized by bath immersion using a 1/500 dilution of m...

  2. Interaction of Human Cytochrome P450 3A4 with Hydrophobicity Probe Nile Red Shows Heterogeneous, Strong Binding

    NASA Astrophysics Data System (ADS)

    Hansen, Jennifer; Guengerich, F.; Martin, Martha; Marsch, Glenn

    2009-03-01

    Human cytochrome P450 3A4 (CYP 3A4) binds an unusually wide variety of substrates, and metabolizes about 50% of all drugs. Steady-state fluorescence spectra were acquired for complexes of CYP 3A4 and the fluorescence probe Nile Red. Difference fluorescence spectra and Hill plots were generated, and Hill coefficients were determined. The fluorescence from multiple Nile Red bound states was observed, with all bound states having higher emission energies than the fluorescence from free Nile Red. Nile Red was titrated into 150nM CYP 3A4, and fluorescence difference spectra showed the quenching of CYP 3A4 tryptophan fluorescence by Nile Red. CYP 3A4 was also added to Nile Red, and changes in the Nile Red fluorescence spectra were monitored. The dissociation constant showed tight binding, with Kd = 44nM. Good fits to the Hill plots were obtained with n = 1, suggesting non-cooperative binding. This study revealed strong, heterogeneous, non-cooperative binding of Nile Red to CYP 3A4.

  3. CHIMERIC WEST NILE/DENGUE VIRUS VACCINE CANDIDATE: PRECLINICAL EVALUATION IN MICE, GEESE, AND MONKEYS FOR SAFETY AND IMMUNOGENICITY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A live attenuated virus vaccine is being developed to protect against West Nile virus (WN) disease in humans. Previously, it was found that chimeric West Nile/dengue viruses (WN/DEN4 and WN/DEN4-delta-30) bearing the membrane precursor and envelope protein genes of WN on a backbone of dengue type 4 ...

  4. BIOLOG MICROLOG® IDENTIFICATION OF Lactococcus garvieae INFECTION IN NILE TILAPIA Oreochromis niloticus AND PINTADO Pseudoplathystoma corruscans FROM BRAZIL

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lactococcus garvieae infection in cultured Nile tilapia, Oreochromis niloticus, and pintado, Pseudoplathystoma corruscans from Brazil is reported. This is the first evidence of the presence of this pathogen from Brazilian fish and the first report of L. garvieae infection in either Nile tilapia or ...

  5. Identification and transcriptional profile of multiple genes in the posterior kidney of Nile tilapia at 6h post bacterial infections

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To understand the molecular mechanisms involved in response of Nile tilapia (Oreochromis niloticus) to bacterial infection, suppression subtractive cDNA hybridization technique was used to identify upregulated genes in the posterior kidney of Nile tilapia at 6h post infection with Aeromonas hydrophi...

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

    NASA Astrophysics Data System (ADS)

    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.

  7. Long-term neurological outcomes in West Nile virus-infected patients: an observational study.

    PubMed

    Weatherhead, Jill E; Miller, Vicki E; Garcia, Melissa N; Hasbun, Rodrigo; Salazar, Lucrecia; Dimachkie, Mazen M; Murray, Kristy O

    2015-05-01

    The Houston West Nile Cohort (HWNC) was founded in 2002 when West Nile virus (WNV) reached Houston, TX. The long-term outcomes following WNV infection are still mostly unknown, though neurological abnormalities up to 1 year postinfection have been documented. We report an observational study of neurological abnormalities at 1-3 and 8-11 years following WNV infection in the HWNC. We conducted standard neurological examinations at two separate time points to assess changes in neurological status over time. The majority of patients (86%, 30/35) with encephalitis had abnormal neurological exam findings at the time of the first assessment compared with uncomplicated fever (27%, 3/11) and meningitis (36%, 5/14) cases. At the time of the second assessment, 57% (4/7) of West Nile fever (WNF), 33% (2/6) of West Nile meningitis (WNM), and 36% (5/14) of West Nile encephalitis (WNE) had developed new neurological complications. The most common abnormalities noted were tandem gait, hearing loss, abnormal reflexes, and muscle weakness. Long-term neurological abnormalities were most commonly found in patients who experienced primary WNV encephalitis. New abnormalities may develop over time regardless of initial clinical infection. Future studies should aim to differentiate neurological consequences due to WNV neuroinvasive infection versus neurological decline related to comorbid conditions. PMID:25802426

  8. Yard flooding by irrigation canals increased the risk of West Nile disease in El Paso, Texas

    PubMed Central

    Cardenas, Victor M.; Jaime, Javier; Ford, Paula B.; Gonzalez, Fernando J.; Carrillo, Irma; Gallegos, Jorge E.; Watts, Douglas M.

    2011-01-01

    Purpose To investigate the effects of use of water from irrigation canals to flood residential yards on the risk of West Nile disease in El Paso, Texas. Methods West Nile disease confirmed cases in 2009–2010 were compared with a random sample of 50 residents of the county according to access to and use of water from irrigation canals by subjects or their neighbors, as well as geo-referenced closest distance between their home address and the nearest irrigation canal. A windshield survey of 600 meters around the study subjects’ home address recorded the presence of irrigation canals. The distance from the residence of 182 confirmed cases of West Nile disease reported in 2003–2010 to canals was compared to that of the centroids of 182 blocks selected at random. Results Cases were more likely than controls to report their neighbors flooded their yards with water from canals. Irrigation canals were more often observed in neighborhoods of cases than of controls. Using the set of addresses of 182 confirmed cases and 182 hypothetic controls the authors found a statistically significant inverse relation with risk of West Nile disease. Conclusions Flooding of yards with water from canals increased the risk of West Nile disease. PMID:21943648

  9. Egyptian mummies record increasing aridity in the Nile valley from 5500 to 1500 yr before present

    NASA Astrophysics Data System (ADS)

    Touzeau, Alexandra; Blichert-Toft, Janne; Amiot, Romain; Fourel, François; Martineau, François; Cockitt, Jenefer; Hall, Keith; Flandrois, Jean-Pierre; Lécuyer, Christophe

    2013-08-01

    Oxygen isotope compositions were measured in teeth (n=29) and bones (n=41) from Egyptian mummies of humans (n=48) in order to track the δ18O evolution of the Nile from 5500 to 1500 B.P. The combination of δ18O values of apatite carbonate and phosphate was used to filter the database for post mortem alteration of bioapatites, while 87Sr/86Sr ratios were used to detect potential allochthonous people buried in the various archeological sites located along the Nile. This approach led to only five apatite samples out of seventy to be discarded from the database. The remaining oxygen isotope compositions of both tooth and bone phosphates from ancient Egyptians were converted into the composition of ingested water ultimately originating from the Nile. It was found that δ18O of Nile waters increases progressively from -1.6 to +1.5 (‰ VSMOW) from the Predynastic (∼5500 B.P.) through the Late Period (∼2550 B.P.). This trend towards higher Nile δ18O values acquired in more recent times is coherent with a general drying trend in Northeast Africa, which was not limited to a drying spell at the end of the Nabtian Pluvial (ca. 12,000 B.P. -ca. 6000 B.P.), but extended far into the following millennia nearly to the beginning of the Common Era (1950 B.P.).

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

    SciTech Connect

    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.

  11. European Surveillance for West Nile Virus in Mosquito Populations

    PubMed Central

    Engler, Olivier; Savini, Giovanni; Papa, Anna; Figuerola, Jordi; Groschup, Martin H.; Kampen, Helge; Medlock, Jolyon; Vaux, Alexander; Wilson, Anthony J.; Werner, Doreen; Jöst, Hanna; Goffredo, Maria; Capelli, Gioia; Federici, Valentina; Tonolla, Mauro; Patocchi, Nicola; Flacio, Eleonora; Portmann, Jasmine; Rossi-Pedruzzi, Anya; Mourelatos, Spiros; Ruiz, Santiago; Vázquez, Ana; Calzolari, Mattia; Bonilauri, Paolo; Dottori, Michele; Schaffner, Francis; Mathis, Alexander; Johnson, Nicholas

    2013-01-01

    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 current status of

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

    ERIC Educational Resources Information Center

    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…

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

    NASA Astrophysics Data System (ADS)

    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

  14. Adsorption of Methylene Blue, Bromophenol Blue, and Coomassie Brilliant Blue by α-chitin nanoparticles.

    PubMed

    Dhananasekaran, Solairaj; Palanivel, Rameshthangam; Pappu, Srinivasan

    2016-01-01

    Expelling of dyestuff into water resource system causes major thread to the environment. Adsorption is the cost effective and potential method to remove the dyes from the effluents. Therefore, an attempt was made to study the adsorption of dyestuff (Methylene Blue (MB), Bromophenol Blue (BPB) and Coomassie Brilliant Blue (CBB)) by α-chitin nanoparticles (CNP) prepared from Penaeus monodon (Fabricius, 1798) shell waste. On contrary to the most recognizable adsorption studies using chitin, this is the first study using unique nanoparticles of ⩽50 nm used for the dye adsorption process. The results showed that the adsorption process increased with increase in the concentration of CNP, contact time and temperature with the dyestuff, whereas the adsorption process decreased with increase in the initial dye concentration and strong acidic pH. The results from Fourier transform infrared (FTIR) spectroscopy confirmed that the interaction between dyestuff and CNP involved physical adsorption. The adsorption process obeys Langmuir isotherm (R (2) values were 0.992, 0.999 and 0.992 for MB, BPB and CBB, and RL value lies between 0 and 1 for all the three dyes) and pseudo second order kinetics (R (2) values were 0.996, 0.999 and 0.996 for MB, BPB and CBB) more effectively. The isotherm and kinetic models confirmed that CNP can be used as a suitable adsorbent material for the removal of dyestuff from effluents. PMID:26843977

  15. Adsorption of Methylene Blue, Bromophenol Blue, and Coomassie Brilliant Blue by α-chitin nanoparticles

    PubMed Central

    Dhananasekaran, Solairaj; Palanivel, Rameshthangam; Pappu, Srinivasan

    2015-01-01

    Expelling of dyestuff into water resource system causes major thread to the environment. Adsorption is the cost effective and potential method to remove the dyes from the effluents. Therefore, an attempt was made to study the adsorption of dyestuff (Methylene Blue (MB), Bromophenol Blue (BPB) and Coomassie Brilliant Blue (CBB)) by α-chitin nanoparticles (CNP) prepared from Penaeus monodon (Fabricius, 1798) shell waste. On contrary to the most recognizable adsorption studies using chitin, this is the first study using unique nanoparticles of ⩽50 nm used for the dye adsorption process. The results showed that the adsorption process increased with increase in the concentration of CNP, contact time and temperature with the dyestuff, whereas the adsorption process decreased with increase in the initial dye concentration and strong acidic pH. The results from Fourier transform infrared (FTIR) spectroscopy confirmed that the interaction between dyestuff and CNP involved physical adsorption. The adsorption process obeys Langmuir isotherm (R2 values were 0.992, 0.999 and 0.992 for MB, BPB and CBB, and RL value lies between 0 and 1 for all the three dyes) and pseudo second order kinetics (R2 values were 0.996, 0.999 and 0.996 for MB, BPB and CBB) more effectively. The isotherm and kinetic models confirmed that CNP can be used as a suitable adsorbent material for the removal of dyestuff from effluents. PMID:26843977

  16. Pre-Pliocene history and depositional facies, Nile Delta, Egypt

    SciTech Connect

    Harms, J.C.; Wray, J.L.

    1988-08-01

    The Nile delta area has a long history of subsidence and deposition that is inferred to extend back to Jurassic or earlier times. Depositional environments, rates of subsidence, and structural events are quite varied during this time span. Deposition was dominated by platform-to-basin carbonate facies from Jurassic to Eocene time and by detrital sediments from the Oligocene onward. Deposits are truly deltaic, in the sense of representing focused deposition at the shoreline by a large integrated river, only from latest Miocene time onward. A probable transition from continental to oceanic crust typical of the southern Mediterranean margin is overlain in the delta area by Mesozoic platform carbonates that appear to change in seismic data northward into slope and basinal facies. This platform margin, which trends east-west through the central delta, is reflected in later stratigraphic and structural characteristics; very thick Tertiary deposits, bathyal facies of Oligocene to Pliocene age, and large rotated fault blocks of Miocene strata occur only north of this margin.

  17. Economic conditions predict prevalence of West Nile virus.

    PubMed

    Harrigan, Ryan J; Thomassen, Henri A; Buermann, Wolfgang; Cummings, Robert F; Kahn, Matthew E; Smith, Thomas B

    2010-01-01

    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. PMID:21103053

  18. West Nile Virus in Mosquitoes of Iranian Wetlands.

    PubMed

    Bagheri, Masoomeh; Terenius, Olle; Oshaghi, Mohammad Ali; Motazakker, Morteza; Asgari, Sassan; Dabiri, Farrokh; Vatandoost, Hassan; Mohammadi Bavani, Mulood; Chavshin, Ali Reza

    2015-12-01

    The West Nile virus (WNV) transmission cycle includes a wide range of migratory wetland birds as reservoirs, mosquitoes as biological vectors, and equines and humans as dead-end hosts. Despite the presence of potential vector species, there is no information about the existence of WNV in mosquito vectors in Iran. The Iranian West Azerbaijan Province is located in the northwestern part of Iran and has borders with Turkey, Iraq, Armenia, and the Republic of Azerbaijan. The current study was conducted to identify the wetland mosquitoes of the West Azerbaijan Province and their infection with WNV. In this study, 2143 specimens were collected, comprising 1541 adults and 602 larvae. Six species belonging to four genera were collected and identified: Anopheles maculipennis sensu lato (s.l.), Culex (Cx.) hortensis, Cx. pipiens s.l., Cx. theileri, Culiseta longiareolata, and Aedes (Ae.) (Ochlerotatus) caspius. In total, 45 pools of mosquitoes were examined. Two of the adult pools collected from the same location showed the presence of WNV in Ae. (Och.) caspius, from Sangar, Makoo County, as confirmed by PCR and sequencing. Due to the discovery of WNV in the mosquito population of the region, and the presence of wetlands and significant populations of migratory birds, the health sector should carefully monitor the factors involved in the cycle of this disease. PMID:26565610

  19. West Nile Virus outbreak in Sardinia, Italy, in 2011.

    PubMed

    Spissu, Nicoletta; Panichi, Giovanni; Montisci, Antonio; Fiore, Filippo

    2013-01-01

    West Nile Virus (WNV) is an enveloped, positive-sense RNA virus belonging to the genus Flavivirus, antigenically related to the Japanese encephalitis complex in the family Flaviviridae. The principal vectors are mosquitoes, in particular Culex spp, and virus amplification seems to occur in susceptible birds that are the principal vertebrate reservoir hosts, whereas humans, horses and other vertebrates are considered incidental or dead-end hosts. The first Italian equine outbreak was reported in late summer of 1998 in Tuscany, in the area surrounding the Fucecchio marshes, where 14 clinical cases of WND in housed equines were recorded. In 2011 WNV appeared for the first time in Sardinia, representing the first clinical cases in equines in Italy in 2011. The outbreak occurred both in humans and in equines. The serological survey performed on 253 equines living in the province of Oristano detected a total of 87 IgG-positive subjects. Among them, 46 horses showed neurological signs such as ataxia, paresis, paralysis, hyperesthesia, muscle fasciculations, seizures, or fever. Nine of them died or were euthanized. In forthcoming years, surveillance of wild birds and insects will be used to forecast the extension and spread of WNV. The information gathered will be used to direct or optimise strategies intended to prevent virus transmission. PMID:23324814

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

    PubMed

    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

  1. Clinical Sentinel Surveillance of Equine West Nile Fever, Spain.

    PubMed

    Saegerman, C; Alba-Casals, A; García-Bocanegra, I; Dal Pozzo, F; van Galen, G

    2016-04-01

    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 data issued from a passive epidemiosurveillance network from September 2010 to December 2011 on horses in Spain were statistically compared and used to develop a predictive diagnostic decision tree, both with the aim to improve the early clinical detection of WNF in horses. Although clinical signs were variable in horses affected by WNF, four clinical signs and the month of occurrence were identified as useful indicators to distinguish between WNF-related and WNF-unrelated cases. The signs that pointed out a presumptive diagnosis of WNF in horses were cranial nerves deficits, limb paralysis, photophobia and nasal discharge. Clinical examination of horses with neurological signs that are not vaccinated against WNV could provide important clues for the early clinical detection of WNF and therefore serve as an alert for possible human viral infections. The study of the clinical pattern of WNF in horses is of importance to enhance awareness and better understanding and to optimize surveillance designs for clinical detection of WNF in horses in advance of epidemic activity affecting humans. PMID:24899369

  2. Predicting human West Nile virus infections with mosquito surveillance data.

    PubMed

    Kilpatrick, A Marm; Pape, W John

    2013-09-01

    West Nile virus (WNV) has become established across the Americas with recent heightened activity causing significant human illness. Surveillance methods to predict the risk of human infection are urgently needed to initiate timely preventative measures and justify the expense of implementing costly or unpopular control measures, such as aerial spraying or curfews. We quantified the links between mosquito surveillance data and the spatiotemporal patterns of 3,827 human WNV cases reported over 5 years in Colorado from 2003 to 2007. Mosquito data were strongly predictive of variation in the number of human WNV infections several weeks in advance in both a spatiotemporal statewide analysis and temporal variation within counties with substantial numbers of human cases. We outline several ways to further improve the predictive power of these data and we quantify the loss of information if no funds are available for testing mosquitoes for WNV. These results demonstrate that mosquito surveillance provides a valuable public health tool for assessing the risk of human arboviral infections, allocating limited public health resources, and justifying emergency control actions. PMID:23825164

  3. West Nile virus: A re-emerging pathogen revisited

    PubMed Central

    Martín-Acebes, Miguel A; Saiz, Juan-Carlos

    2012-01-01

    West Nile virus (WNV), a flavivirus of the Flaviviridae family, is maintained in nature in an enzootic transmission cycle between avian hosts and ornithophilic mosquito vectors, although the virus occasionally infects other vertebrates. WNV causes sporadic disease outbreaks in horses and humans, which may result in febrile illness, meningitis, encephalitis and flaccid paralysis. Until recently, its medical and veterinary health concern was relatively low; however, the number, frequency and severity of outbreaks with neurological consequences in humans and horses have lately increased in Europe and the Mediterranean basin. Since its introduction in the Americas, the virus spread across the continent with worrisome consequences in bird mortality and a considerable number of outbreaks among humans and horses, which have resulted in the largest epidemics of neuroinvasive WNV disease ever documented. Surprisingly, its incidence in human and animal health is very different in Central and South America, and the reasons for it are not yet understood. Even though great advances have been obtained lately regarding WNV infection, and although efficient equine vaccines are available, no specific treatments or vaccines for human use are on the market. This review updates the most recent investigations in different aspects of WNV life cycle: molecular virology, transmission dynamics, host range, clinical presentations, epidemiology, ecology, diagnosis, control, and prevention, and highlights some aspects that certainly require further research. PMID:24175211

  4. Experimental Infection of Horses with West Nile virus

    PubMed Central

    Bowen, Richard A.; Cropp, Bruce C.; Sullivan, Kevin G.; Davis, Brent S.; Komar, Nieholas; Godsey, Marvin; Baker, Dale; Hettler, Danielle L.; Holmes, Derek A.; Biggerstaff, Brad J.; Mitchell, Carl J.

    2002-01-01

    A total of 12 horses of different breeds and ages were infected with West Nile virus (WNV) via the bites of infected Aedes albopictus mosquitoes. Half the horses were infected with a viral isolate from the brain of a horse (BC787), and half were infected with an isolate from crow brain (NY99-6625); both were NY99 isolates. Postinfection, uninfected female Ae. albopictus fed on eight of the infected horses. In the first trial, Nt antibody titers reached >1:320, 1:20, 1:160, and 1:80 for horses 1 to 4, respectively. In the second trial, the seven horses with subclinical infections developed Nt antibody titers >1:10 between days 7 and 11 post infection. The highest viremia level in horses fed upon by the recipient mosquitoes was approximately 460 Vero cell PFU/mL. All mosquitoes that fed upon viremic horses were negative for the virus. Horses infected with the NY99 strain of WNV develop low viremia levels of short duration; therefore, infected horses are unlikely to serve as important amplifying hosts for WNV in nature. PMID:11971771

  5. West Nile Virus in Resident Birds from Yucatan, Mexico.

    PubMed

    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

  6. West Nile Virus Outbreak in North American Owls, Ontario, 2002

    PubMed Central

    Barker, Ian K.; Lindsay, Robbin; Dibernardo, Antonia; McKeever, Katherine; Hunter, Bruce

    2004-01-01

    From July to September 2002, an outbreak of West Nile virus (WNV) caused a high number of deaths in captive owls at the Owl Foundation, Vineland, Ontario, Canada. Peak death rates occurred in mid-August, and the epidemiologic curve resembled that of corvids in the surrounding Niagara region. The outbreak occurred in the midst of a louse fly (Icosta americana, family Hippoboscidae) infestation. Of the flies tested, 16 (88.9 %) of 18 contained WNV RNA. Species with northern native breeding range and birds >1 year of age were at significantly higher risk for WNV-related deaths. Species with northern native breeding range and of medium-to-large body size were at significantly higher risk for exposure to WNV. Taxonomic relations (at the subfamily level) did not significantly affect exposure to WNV or WNV-related deaths. Northern native breeding range and medium-to-large body size were associated with earlier death within the outbreak period. Of the survivors, 69 (75.8 %) of 91 were seropositive for WNV. PMID:15663850

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

    PubMed

    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

  8. Functional Analysis of West Nile Virus Proteins in Human Cells.

    PubMed

    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

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

    PubMed

    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

  10. Does reservoir host mortality enhance transmission of West Nile virus?

    PubMed Central

    Foppa, Ivo M; Spielman, Andrew

    2007-01-01

    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. PMID:17498307

  11. Hydroclimatic Assessment of West Nile Virus Occurrence Across Continental US

    NASA Astrophysics Data System (ADS)

    Billian, H. E.; Jutla, A.; Colwell, R. R.

    2014-12-01

    West Nile virus (WNV) is the most widely infections from arbovirus in mid-latitudes, having reached the Western Hemisphere in 1999. As a vector-borne disease, WNV is primarily spread by mosquitoes; the disease is predominantly found in tropical and temperate regions of the world, and is now considered an endemic pathogen in the United States, Africa, Asia, Australia, the Middle East, and Europe. Environmental processes play a vital role in the trigger of WNV. Here, using logistical regression models, we quantified relationships between hydroclimatic processes and mosquito abundance for WNV across the continental USA using precipitation and temperature at different spatial and temporal scales. It will be shown that reported cases of this disease are more prevalent during spring and summer months in the entire country, when there is more precipitation and higher surface air temperatures for 2003 to 2013. The key impacts of this research are those related to the improvement of human health, and a means to predict mosquito breeding patterns long term as they relate to the prevalence of vector-borne illnesses.

  12. West Nile virus transmission and ecology in birds

    USGS Publications Warehouse

    McLean, R.G.; Ubico, S.R.; Docherty, D.E.; Hansen, W.R.; Sileo, L.; Mcnamara, T.S.

    2001-01-01

    The ecology of the strain of West Nile virus (WNV) introduced into the United States in 1999 has similarities to the native flavivirus, St. Louis encephalitis (SLE) virus, but has unique features not observed with SLE virus or with WNV in the old world. The primary route of transmission for most of the arboviruses in North America is by mosquito, and infected native birds usually do not suffer morbidity or mortality. An exception to this pattern is eastern equine encephalitis virus, which has an alternate direct route of transmission among nonnative birds, and some mortality of native bird species occurs. The strain of WNV circulating in the northeastern United States is unique in that it causes significant mortality in exotic and native bird species, especially in the American crow (Corvus brachyrhynchos). Because of the lack of information on the susceptibility and pathogenesis of WNV for this species, experimental studies were conducted at the USGS National Wildlife Health Center. In two separate studies, crows were inoculated with a 1999 New York strain of WNV, and all experimentally infected crows died. In one of the studies, control crows in regular contact with experimentally inoculated crows in the same room but not inoculated with WNV succumbed to infection. The direct transmission between crows was most likely by the oral route. Inoculated crows were viremic before death, and high titers of virus were isolated from a variety of tissues. The significance of the experimental direct transmission among captive crows is unknown.

  13. Economic Conditions Predict Prevalence of West Nile Virus

    PubMed Central

    Buermann, Wolfgang; Cummings, Robert F.; Kahn, Matthew E.; Smith, Thomas B.

    2010-01-01

    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. PMID:21103053

  14. West Nile Virus Encephalitis in a Patient with Neuroendocrine Carcinoma

    PubMed Central

    2016-01-01

    Importance. Oftentimes, when patients with metastatic cancer present with acute encephalopathy, it is suspected to be secondary to their underlying malignancy. However, there are multiple causes of delirium such as central nervous system (CNS) infections, electrolyte abnormalities, and drug adverse reactions. Because West Nile Virus (WNV) neuroinvasive disease has a high mortality rate in immunosuppressed patients, a high index of suspicion is required in patients who present with fever, altered mental status, and other neurological symptoms. Observations. Our case report details a single patient with brain metastases who presented with unexplained fever, encephalopathy, and new-onset tremors. Initially, it was assumed that his symptoms were due to his underlying malignancy or seizures. However, because his unexplained fevers persisted, lumbar puncture was pursued. Cerebrospinal fluid analysis included WNV polymerase chain reaction and serologies were ordered which eventually led to diagnosis of WNV encephalitis. Conclusions and Relevance. Patients with metastatic cancer who present with encephalopathy are often evaluated with assumption that malignancy is the underlying etiology. This can lead to delays in diagnosis and possible mistreatment. Our case highlights the importance of maintaining a broad differential diagnosis and an important diagnostic consideration of WNV encephalitis in patients with cancer. PMID:27516915

  15. West Nile virus detection in nonvascular feathers from avian carcasses.

    PubMed

    Nemeth, Nicole M; Young, Ginger R; Burkhalter, Kristen L; Brault, Aaron C; Reisen, William K; Komar, Nicholas

    2009-09-01

    West Nile virus (WNV) is a public health threat and has caused the death of thousands of North American birds. As such, surveillance for WNV has been ongoing, utilizing numerous biological specimens and testing methods. Nonvascular (i.e., fully grown) feathers would provide a simple method of collection from either dead or live birds of all ages and molt cycles, with presumably less biosafety risk compared with other specimen types, including feather pulp. The current study evaluates WNV detection in nonvascular feathers removed from naturally infected avian carcasses of several species groups. Feathers of corvid passeriforms had the highest sensitivity of detection (64%), followed by noncorvid passeriforms (43%), columbiforms (33%), and falconiforms (31%). Storing feathers for 1 year at -20 degrees C or at ambient room temperature resulted in detection rates of infectious WNV of 16% and zero, respectively, but had no effect on detection rates of WNV RNA in a subset of matched feather pairs (47% for both storage temperatures). The efficacy of WNV detection in nonvascular feathers is greatly enhanced by testing multiple feathers. The advantages of using nonvascular feathers over other tissues may outweigh the relatively low detectability of WNV RNA in certain situations such as remote areas lacking resources for acquiring other types of samples or maintaining the cold chain. PMID:19737756

  16. Uncovering blue diffuse dwarf galaxies

    NASA Astrophysics Data System (ADS)

    James, Bethan L.; Koposov, Sergey; Stark, Daniel P.; Belokurov, Vasily; Pettini, Max; Olszewski, Edward W.

    2015-04-01

    Extremely metal poor (XMP) galaxies are known to be very rare, despite the large numbers of low-mass galaxies predicted by the local galaxy luminosity function. This paper presents a subsample of galaxies that were selected via a morphology-based search on Sloan Digital Sky Survey images with the aim of finding these elusive XMP galaxies. By using the recently discovered XMP galaxy, Leo P, as a guide, we obtained a collection of faint, blue systems, each with isolated H II regions embedded in a diffuse continuum, that have remained optically undetected until now. Here we show the first results from optical spectroscopic follow-up observations of 12 of ˜100 of these blue diffuse dwarf (BDD) galaxies yielded by our search algorithm. Oxygen abundances were obtained via the direct method for eight galaxies, and found to be in the range 7.45 < 12 + log (O/H) < 8.0, with two galaxies being classified as XMPs. All BDDs were found to currently have a young star-forming population (<10 Myr) and relatively high ionization parameters of their H II regions. Despite their low luminosities (-11 ≲ MB ≲ -18) and low surface brightnesses (˜23-25 mag arcsec-2), the galaxies were found to be actively star forming, with current star formation rates between 0.0003 and 0.078 M⊙ yr-1. From our current subsample, BDD galaxies appear to be a population of non-quiescent dwarf irregular galaxies, or the diffuse counterparts to blue compact galaxies and as such may bridge the gap between these two populations. Our search algorithm demonstrates that morphology-based searches are successful in uncovering more diffuse metal-poor star-forming galaxies, which traditional emission-line-based searches overlook.

  17. Reconstructing the late-Holocene fluvial dynamics of the River Nile in central Egypt

    NASA Astrophysics Data System (ADS)

    Verstraeten, G.; Willems, H.; Notebaert, B.; Dusar, B.; de Laet, V.; Marinova, E.; Kaniewski, D.

    2009-04-01

    From 2004 on, geoarchaeological research is being carried out in the Nile floodplain near Dayr al Bershah, an important ancient Egyptian funeral site in central Egypt covering burial sites from the Old to the New Kingdom. The reconstruction of the ancient Nilotic landscape and human-environment interactions alongside the transition from the lower desert to the Nile floodplain was approached multidisciplinarily. On the one hand, in the floodplain more than 300 detailed hand augerings up to 6 m depth were made, and compared with electrical resistivity imaging profiles with lengths up to 1200 m and depths from 20-45 m. These data were complemented with information obtained from historical map analysis, remote sensing imagery (ASTER, Quickbird, Corona) and digital elevation models (SRTM). Preliminary results show good correspondence between the sedimentological analysis of the hand augerings and the electrical resistivity values: sandy paleochannel deposits show high resistivity values, whereas silty to clay-rich floodplain deposits show very low ER-values. All information sources show several Nile branches being active prior to the closure of the Aswan Dam in 1964, and most branches can also be traced applying topographical analysis, confirming the sedimentological and ER analyses. However, one major branch relatively close to the eastern edge of the floodplain and the current village of Dayr al Bershah could only be traced by coring and ER as it is no longer topographically visible. First dating results suggest this Nile branch being at least 600 years old and some parts being active up to 2000 years ago. Moreover, several radiocarbon dates from the Nile floodplain show there is no clear age-depth relationship present within the floodplain sediments, as a strong negative exponential relationship between the sedimentation rate in mm.a-1 and the sediment age has been proven. This indicates large parts of the floodplain near Dayr al Bershah have been reworked over the

  18. Climate-based models for West Nile Culex mosquito vectors in the Northeastern US

    NASA Astrophysics Data System (ADS)

    Gong, Hongfei; Degaetano, Arthur T.; Harrington, Laura C.

    2011-05-01

    Climate-based models simulating Culex mosquito population abundance in the Northeastern US were developed. Two West Nile vector species, Culex pipiens and Culex restuans, were included in model simulations. The model was optimized by a parameter-space search within biological bounds. Mosquito population dynamics were driven by major environmental factors including temperature, rainfall, evaporation rate and photoperiod. The results show a strong correlation between the timing of early population increases (as early warning of West Nile virus risk) and decreases in late summer. Simulated abundance was highly correlated with actual mosquito capture in New Jersey light traps and validated with field data. This climate-based model simulates the population dynamics of both the adult and immature mosquito life stage of Culex arbovirus vectors in the Northeastern US. It is expected to have direct and practical application for mosquito control and West Nile prevention programs.

  19. West Nile Virus Outbreak in Horses, Southern France, 2000: Results of a Serosurvey

    PubMed Central

    Chevalier, Véronique; Pouillot, Régis; Labie, Jacques; Marendat, Ingrid; Murgue, Bernadette; Zeller, Hervé; Zientara, Stéphan

    2002-01-01

    During late summer and autumn 2000, a West Nile fever outbreak in southern France resulted in 76 equine clinical cases; 21 horses died. We report the results of a large serosurvey of all equines within a 10-km radius of laboratory-confirmed cases. Blood samples were obtained from 5,107 equines, distributed in groups of 1 to 91 animals. West Nile virus immunoglobulin (Ig) G antibodies were found in 8.5% of animals (n=432). Forty-two percent of the IgG-positive animals were also IgM positive. Horses living in small groups were more affected than those in large groups. The results suggest that West Nile virus is not endemic in the affected area, the Camargue; rather, sporadic outbreaks are separated by long silent periods. PMID:12141961

  20. High-latitude eruptions cast shadow over the African monsoon and the flow of the Nile

    NASA Astrophysics Data System (ADS)

    Oman, Luke; Robock, Alan; Stenchikov, Georgiy L.; Thordarson, Thorvaldur

    2006-09-01

    Nile River records indicate very low flow following the 1783-1784 Laki volcanic eruption, as well as after other high-latitude volcanic eruptions. As shown by climate model simulations of the Laki eruption, significant cooling (-1° to -3°C) of the Northern Hemisphere land masses during the boreal summer of 1783 resulted in a strong dynamical effect of weakening the African and Indian monsoon circulations, with precipitation anomalies of -1 to -3 mm/day over the Sahel of Africa, thus producing the low Nile flow. Future high-latitude eruptions would significantly impact the food and water supplies in these areas. Using observations of the flow of the Nile River, this new understanding is used to support a date of 939 for the beginning of the eruption of the Eldgjá volcano in Iceland, the largest high-latitude eruption of the past 1500 years.

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

    PubMed

    Myburgh, Jan G; Huchzermeyer, Fritz W; Soley, John T; Booyse, Dirk G; Groenewald, Herman B; Bekker, Lizette C; Iguchi, Taisen; 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 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. PMID:23327128

  2. The mixing of blue stragglers

    NASA Astrophysics Data System (ADS)

    Kafka, Stella; De Propris, Roberto

    2012-08-01

    We propose to obtain high resolution spectroscopy for a sample of 17 blue stragglers in M67, in order to measure abundances of Beryllium, Carbon, Oxygen and the Carbon isotope (13C/12C) abundance ratio. The main aim of this project is to measure indications of deep mixing and therefore elucidate the processes responsible for the formation of these stars, whether stellar collisions, WUMa type mass transfer or Algol-like binary evolution. The data will also allow us to measure the importance of magnetic fields and search for faint companions via their effect on other spectral lines

  3. Purification and crystallization of dengue and West Nile virus NS2B–NS3 complexes

    SciTech Connect

    D’Arcy, Allan Chaillet, Maxime; Schiering, Nikolaus; Villard, Frederic; Lim, Siew Pheng; Lefeuvre, Peggy; Erbel, Paul

    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.

  4. Decadal biogeochemical history of the south east Levantine basin: Simulations of the river Nile regimes

    NASA Astrophysics Data System (ADS)

    Suari, Yair; Brenner, Steve

    2015-08-01

    The south eastern Mediterranean is characterized by antiestuarine circulation which leads to extreme oligotrophic conditions. The Nile river that used to transport fresh water and nutrients into the basin was dammed in 1964 which led to a drastic reduction of fresh water fluxes, and later, changes in Egyptian agriculture and diet led to increased nutrient fluxes. In this paper we present the results of simulations with a biogeochemical model of the south eastern Mediterranean. Four experiments were conducted: (1) present day without riverine inputs; (2) Nile before damming (pre-1964); (3) post-damming 1995 Nile; and (4) fresh water and nutrient discharges of Israeli coastal streams. The present day input simulation (control run) successfully reproduced measured nutrient concentrations, with the exception of simulated chlorophyll concentrations which were slightly higher than observed. The pre-1964 Nile simulation showed a salinity reduction of 2 psu near the Egyptian coast and 0.5 psu along the Israeli coast, as well as elevated chlorophyll a concentrations mostly east of the Nile delta and north to Cyprus. The spring bloom extended from its present peak during February-March to a peak during February-May. The 1995 Nile simulation showed increased chlorophyll a concentrations close to the Egyptian coast. The Israeli coastal stream simulation showed that the effect of the Israeli coastal stream winter flow on chlorophyll converged to control concentrations within about one month, demonstrating the stability and sensitivity of the model to external forcing. The results of this study demonstrate the significance of fresh water fluxes in maintaining marine productivity, which may have large scale effects on the marine ecosystem.

  5. Yellow fever vector live-virus vaccines: West Nile virus vaccine development.

    PubMed

    Arroyo, J; Miller, C A; Catalan, J; Monath, T P

    2001-08-01

    By combining molecular-biological techniques with our increased understanding of the effect of gene sequence modification on viral function, yellow fever 17D, a positive-strand RNA virus vaccine, has been manipulated to induce a protective immune response against viruses of the same family (e.g. Japanese encephalitis and dengue viruses). Triggered by the emergence of West Nile virus infections in the New World afflicting humans, horses and birds, the success of this recombinant technology has prompted the rapid development of a live-virus attenuated candidate vaccine against West Nile virus. PMID:11516995

  6. Diatoms from the Quaternary sediments of the Nile Delta, Egypt, and their palaeoecological significance

    NASA Astrophysics Data System (ADS)

    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.

  7. Meningitis-Retention Syndrome as a Presentation of West Nile Virus Meningitis

    PubMed Central

    Laengvejkal, Pavis; Argueta, Erwin; Limsuwat, Chok; Nugent, Kenneth

    2013-01-01

    A 26-year-old previously healthy man presented with fever, urinary retention, nuchal rigidity, and hyperreflexia but with a clear sensorium. His initial spinal fluid results were consistent with aseptic meningitis from West Nile virus infection, and this was confirmed by serological studies on blood and cerebrospinal fluid. Computed tomography and magnetic resonance imaging studies were unremarkable. He received supportive care and urinary catheterization to prevent bladder injury from overdistension. He was discharged home without recurrence of urinary retention after five days of hospitalization. Therefore, this case report describes the first case of West Nile virus meningitis in a patient with the meningitis-retention syndrome. PMID:23983716

  8. Mosquitoes and the Environment in Nile Delta Villages with Previous Rift Valley Fever Activity.

    PubMed

    Zayed, Abdelbaset B; Britch, Seth C; Soliman, Mohamed I; Linthicum, Kenneth J

    2015-06-01

    Egypt is affected by serious human and animal mosquito-borne diseases such as Rift Valley fever (RVF). We investigated how potential RVF virus mosquito vector populations are affected by environmental conditions in the Nile Delta region of Egypt by collecting mosquitoes and environmental data from 3 key governorates before and after 2012 seasonal flooding. We found that environmental effects varied among species, life stages, pre- and postflood groupings, and geographic populations of the same species, and that mosquito community composition could change after flooding. Our study provides preliminary data for modeling mosquitoes and mosquito-borne diseases in the Nile Delta region. PMID:26181689

  9. Nile Red Detection of Bacterial Hydrocarbons and Ketones in a High-Throughput Format

    SciTech Connect

    Pinzon, NM; Aukema, KG; Gralnick, JA; Wackett, LP

    2011-06-28

    A method for use in high-throughput screening of bacteria for the production of long-chain hydrocarbons and ketones by monitoring fluorescent light emission in the presence of Nile red is described. Nile red has previously been used to screen for polyhydroxybutyrate (PHB) and fatty acid esters, but this is the first report of screening for recombinant bacteria making hydrocarbons or ketones. The microtiter plate assay was evaluated using wild-type and recombinant strains of Shewanella oneidensis and Escherichia coli expressing the enzyme OleA, previously shown to initiate hydrocarbon biosynthesis. The strains expressing exogenous Stenotrophomonas maltophilia oleA, with increased levels of ketone production as determined by gas chromatography-mass spectrometry, were distinguished with Nile red fluorescence. Confocal microscopy images of S. oneidensis oleA-expressing strains stained with Nile red were consistent with a membrane localization of the ketones. This differed from Nile red staining of bacterial PHB or algal lipid droplets that showed intracellular inclusion bodies. These results demonstrated the applicability of Nile red in a high-throughput technique for the detection of bacterial hydrocarbons and ketones. IMPORTANCE In recent years, there has been renewed interest in advanced biofuel sources such as bacterial hydrocarbon production. Previous studies used solvent extraction of bacterial cultures followed by gas chromatography-mass spectrometry (GC-MS) to detect and quantify ketones and hydrocarbons (Beller HR, Goh EB, Keasling JD, Appl. Environ. Microbiol. 76: 1212-1223, 2010; Sukovich DJ, Seffernick JL, Richman JE, Gralnick JA, Wackett LP, Appl. Environ. Microbiol. 76: 3850-3862, 2010). While these analyses are powerful and accurate, their labor-intensive nature makes them intractable to high-throughput screening; therefore, methods for rapid identification of bacterial strains that are overproducing hydrocarbons are needed. The use of high

  10. A 7500-year strontium isotope record from the northwestern Nile delta (Maryut lagoon, Egypt)

    NASA Astrophysics Data System (ADS)

    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

  11. Geothermal Technologies Program Blue Ribbon Panel Recommendations

    SciTech Connect

    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

  12. The Blue Marble 43 Years Later

    Atmospheric Science Data Center

    2016-02-18

    article title:  The Blue Marble 43 Years Later View larger image Here ... points over more than four decades apart. The iconic "Blue Marble" view on the left was taken 43 years ago on December 7, 1972 from Apollo ... points over more than four decades apart. The iconic "Blue Marble" view on the left was taken 43 years ago on December 7, 1972 from Apollo ...

  13. The Blue Dots Initiative and Roadmapping Exercise

    NASA Astrophysics Data System (ADS)

    Coudé du Foresto, V.

    2010-10-01

    The Blue Dots initiative (a grassroot effort to build a scientific community in Europe around the exoplanet theme) is introduced. The Blue Dots activities include the elaboration of a roadmap towards the spectroscopic characterization of habitable exoplanets, a summary of which is presented here. While the roadmap will need to be updated regularly, it is expected that the methodology developed within Blue Dots will provide a durable framework for the elaboration of future revisions.

  14. Comprehensive mapping of common immunodominant epitopes in the West Nile virus nonstructural protein 1 recognized by avian antibody responses.

    PubMed

    Sun, Encheng; Zhao, Jing; Liu, Nihong; Yang, Tao; Xu, Qingyuan; Qin, Yongli; Bu, Zhigao; Yang, Yinhui; Lunt, Ross A; Wang, Linfa; Wu, Donglai

    2012-01-01

    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 subunit vaccines

  15. The Risk of West Nile Virus Infection Is Associated with Combined Sewer Overflow Streams in Urban Atlanta, Georgia, USA

    PubMed Central

    Vazquez-Prokopec, Gonzalo M.; Vanden Eng, Jodi L.; Kelly, Rosmarie; Mead, Daniel G.; Kolhe, Priti; Howgate, James; Kitron, Uriel; Burkot, Thomas R.

    2010-01-01

    Background At present, the factors favoring transmission and amplification of West Nile Virus (WNV) within urban environments are poorly understood. In urban Atlanta, Georgia, the highly polluted waters of streams affected by combined sewer overflow (CSO) represent significant habitats for the WNV mosquito vector Culex quinquefasciatus. However, their contribution to the risk of WNV infection in humans and birds remains unclear. Objectives Our goals were to describe and quantify the spatial distribution of WNV infection in mosquitoes, humans, and corvids, such as blue jays and American crows that are particularly susceptible to WNV infection, and to assess the relationship between WNV infection and proximity to CSO-affected streams in the city of Atlanta, Georgia. Materials and methods We applied spatial statistics to human, corvid, and mosquito WNV surveillance data from 2001 through 2007. Multimodel analysis was used to estimate associations of WNV infection in Cx. quinquefasciatus, humans, and dead corvids with selected risk factors including distance to CSO streams and catch basins, land cover, median household income, and housing characteristics. Results We found that WNV infection in mosquitoes, corvids, and humans was spatially clustered and statistically associated with CSO-affected streams. WNV infection in Cx. quinquefasciatus was significantly higher in CSO compared with non-CSO streams, and WNV infection rates among humans and corvids were significantly associated with proximity to CSO-affected streams, the extent of tree cover, and median household income. Conclusions Our study strongly suggests that CSO-affected streams are significant sources of Cx. quinquefasciatus mosquitoes that may facilitate WNV transmission to humans within urban environments. Our findings may have direct implications for the surveillance and control of WNV in other urban centers that continue to use CSO systems as a waste management practice. PMID:20529765

  16. Morphological responses of wheat to blue light

    NASA Technical Reports Server (NTRS)

    Barnes, C.; Bugbee, B.

    1992-01-01

    Blue light significantly increased tillering in wheat (Triticum aestivum L.) plants grown at the same photosynthetic photon flux (PPF). Plants were grown under two levels of blue light (400-500 nm) in a controlled environment with continuous irradiation. Plants received either 50 micromoles m-2 s-1 of blue light or 2 micromoles m-2 s-1 blue light from filtered metal halide lamps at a total irradiance of 200 micromoles m-2 s-1 PPF (400-700 nm). Plants tillered an average of 25% more under the higher level of blue light. Blue light also caused a small, but consistent, increase in main culm development, measured as Haun stage. Leaf length was reduced by higher levels of blue light, while plant dry-mass was not significantly affected by blue light. Applying the principle of equivalent light action, the results suggest that tillering and leaf elongation are mediated by the blue-UV light receptor(s) because phytochrome photoequilibrium for each treatment were nearly identical.

  17. Polymer stabilized and dispersed blue phases

    NASA Astrophysics Data System (ADS)

    Kemiklioglu, Emine

    Blue phase liquid crystal (BPLC) materials have potential for advanced applications of display material and technology based on their optical behaviors, such as field-induced birefringence and sub-millisecond response time, which is at least one order of magnitude faster than the present nematic liquid crystal based displays. Since blue phases appear in the narrow temperature range between the chiral nematic and the isotropic phases, there is a temperature range limitation for the application of blue phase liquid crystal. In this dissertation, we have developed blue phase liquid crystal materials with a wide temperature range and low driving voltage. The first goal was to develop wide-temperature range blue phase liquid crystal materials using several stabilization methods notably polymer stabilization, doping of carbon-nanotubes and bent-core molecules. The temperature range could be expanded more than 54°C via the polymer stabilization. The second goal was to explore the polymer dispersed blue phase liquid crystal combining the advantages of the polymer dispersion method and blue phase materials. Polymer encapsulated blue phase films showed a large Kerr constant, low switching voltage and fast response time. Moreover, the temperature range of encapsulated blue phase films were successfully expanded from 9°C to 54°C .

  18. Optically tuneable blue phase photonic band gaps

    SciTech Connect

    Liu, H.-Y.; Wang, C.-T.; Hsu, C.-Y.; Lin, T.-H.; Liu, J.-H.

    2010-03-22

    This study investigates an optically switchable band gap of photonic crystal that is based on an azobenzene-doped liquid crystal blue phase. The trans-cis photoisomerization of azobenzene deforms the cubic unit cell of the blue phase and shifts the photonic band gap. The fast back-isomerization of azobenzene was induced by irradiation with different wavelengths light. The crystal structure is verified using Kossel diffraction diagram. An optically addressable blue phase display, based on Bragg reflection from the photonic band gap, is also demonstrated. The tunable ranges are around red, green, and blue wavelengths and exhibit a bright saturated color.

  19. Detection and sequencing of West Nile virus RNA from human urine and serum samples during the 2014 seasonal period.

    PubMed

    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

  20. A phylogenetic approach to following West Nile virus in Connecticut

    PubMed Central

    Anderson, John F.; Vossbrinck, Charles R.; Andreadis, Theodore G.; Iton, Anthony; Beckwith, William H.; Mayo, Donald R.

    2001-01-01

    The 1999 outbreak of West Nile (WN) virus in the northeastern United States was the first known natural occurrence of this flavivirus in the Western Hemisphere. In 1999 and 2000, 82 independent Connecticut WN virus isolates were cultured from nine species of birds, five species of mosquitoes, and one striped skunk. Nucleotide sequences obtained from these isolates identified 30 genetic changes, compared with WN-NY99, in a 921-nt region of the viral genome beginning at nucleotide position 205 and ending at 1125. This region encodes portions of the nucleocapsid and envelope proteins and includes the entire coding regions for the premembrane and membrane proteins. Amino acid changes occurred at seven loci in six isolates relative to the WN-NY99 strain. Although 34 of the isolates showed sequences identical to the WN-NY99 isolate, we were able to show geographical-based clusters of mutations. In particular, 26 isolates were characterized by mutation of C to T at position 858. This group apparently originated in Stamford, CT and disseminated to sites located as far as 54 miles from Stamford. Sequences of WN virus isolated from both brain and heart tissues from the same avian host were identical in all 14 tested individual birds, suggesting that the mutations we have documented are real and not caused by culture, RNA extraction, or PCR procedures. We conclude that this portion of the viral genome will enable us to follow the geographical and temporal movement of variant WN virus strains as they adapt to North America. PMID:11606791

  1. First isolation of West Nile virus from a dromedary camel

    PubMed Central

    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

  2. Hydrologic variability and the dynamics of West Nile virus transmission

    NASA Astrophysics Data System (ADS)

    Shaman, J. L.

    2011-12-01

    West Nile virus (WNV) first emerged in North America in New York City during 1999 and since that time has spread throughout the continent and settled into a pattern of local endemicity in which outbreaks of variable size develop in some years but not others. Predicting where and when these outbreaks will develop is an issue of considerable public health importance. Spillover transmission of WNV to humans typically occurs when infection rates among vector mosquitoes are elevated. Mosquito infection rates are not constant through time but instead increase when newly emergent mosquitoes can more readily acquire WNV by blood-meal feeding on available, infected animal hosts. Such an increase of vector mosquito infection rates is termed amplification and is facilitated for WNV by intense zoonotic transmission of the virus among vector mosquitoes and avian hosts. Theory, observation and model simulations indicate that amplification is favored when mosquito breeding habitats and bird nesting and roosting habitats overlap. Both vector mosquitoes and vertebrate hosts depend on water resources; mosquitoes are critically dependent on the availability of standing water, as the first 3 stages of the mosquito life cycle, egg, larvae, pupae, are aquatic. Here it is shown that hydrologic variability often determines where and when vector mosquitoes and avian hosts congregate together, and when the amplification of WNV is more likely. Measures of land surface wetness and pooling, from ground observation, satellite observation, or numerical modeling, can provide reliable estimates of where and when WNV transmission hotspots will arise. Examples of this linkage between hydrology and WNV activity are given for Florida, Colorado and New York, and an operational system for monitoring and forecasting WNV risk in space and time is presented for Florida.

  3. West Nile virus methyltransferase domain interacts with protein kinase G

    PubMed Central

    2013-01-01

    Background The flaviviral nonstructural protein 5 (NS5) is a phosphoprotein, though the precise identities and roles of many specific phosphorylations remain unknown. Protein kinase G (PKG), a cGMP-dependent protein kinase, has previously been shown to phosphorylate dengue virus NS5. Methods We used mass spectrometry to specifically identify NS5 phosphosites. Co-immunoprecipitation assays were used to study protein-protein interactions. Effects on viral replication were measured via replicon system and plaque assay titering. Results We identified multiple sites in West Nile virus (WNV) NS5 that are phosphorylated during a WNV infection, and showed that the N-terminal methyltransferase domain of WNV NS5 can be specifically phosphorylated by PKG in vitro. Expressing PKG in cell culture led to an enhancement of WNV viral production. We hypothesized this effect on replication could be caused by factors beyond the specific phosphorylations of NS5. Here we show for the first time that PKG is also able to stably interact with a viral substrate, WNV NS5, in cell culture and in vitro. While the mosquito-borne WNV NS5 interacted with PKG, tick-borne Langat virus NS5 did not. The methyltransferase domain of NS5 is able to mediate the interaction between NS5 and PKG, and mutating positive residues in the αE region of the methyltransferase interrupts the interaction. These same mutations completely inhibited WNV replication. Conclusions PKG is not required for WNV replication, but does make a stable interaction with NS5. While the consequence of the NS5:PKG interaction when it occurs is unclear, mutational data demonstrates that this interaction occurs in a region of NS5 that is otherwise necessary for replication. Overall, the results identify an interaction between virus and a cellular kinase and suggest a role for a host kinase in enhancing flaviviral replication. PMID:23876037

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

    NASA Astrophysics Data System (ADS)

    Onyutha, C.; Willems, P.

    2015-05-01

    Spatiotemporal variability in annual and seasonal rainfall totals were assessed at 37 locations of the Nile Basin in Africa using quantile perturbation method (QPM). To get insight into the spatial difference in rainfall statistics, the stations were grouped based on the pattern of the long-term mean (LTM) 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 (SLP) and sea surface temperature (SST). Further investigations to support the obtained correlations were made using a total of 10 climate indices. It was possible to obtain three 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 from 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 Ocean 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-September rainfall of group B has strong connection to the influence from the Indian Ocean. For the March-May (October-February) rainfall of group A (C), possible links to the Atlantic and Indian oceans were found.

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

    NASA Astrophysics Data System (ADS)

    Onyutha, C.; Willems, P.

    2014-10-01

    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.

  6. Detection of West Nile virus in large pools of mosquitoes.

    PubMed

    Sutherland, Genevieve L; Nasci, Roger S

    2007-12-01

    We conducted a laboratory evaluation of the ability of commercial antigen-capture assays, the Rapid Analyte Measurement Platform (RAMP) and the VecTest wicking assay, as well as Real Time reverse transcriptase polymerase chain reaction (RT-PCR, Taqman) and Vero cell plaque assay to detect West Nile virus (WNV) in large mosquito pools. Real-Time PCR (Taqman) was the most sensitive, detecting WNV ribonucleic acid (RNA) in 100% of samples containing a single infected mosquito in pool sizes of up to 500 mosquitoes. Mosquito body tissues minimally impacted the ability of Real Time RT-PCR to detect WNV in a pool size of 500, reducing sensitivity by 0.6 log10 plaque-forming units (PFU)/ml. Vero cell plaque assay detected live virus from a single infected mosquito in 100% of pools containing up to 200 mosquitoes, but was unreliable at larger pool sizes. VecTest detected 100% of positive pools containing 50 mosquitoes with 5.8 log10 PFU/ml virus, 100 mosquitoes with 5.9 log10 PFU/ml, and 200 mosquitoes with 5.2 log10 PFU/ ml. The RAMP assay detected 100% of positive pools containing 50 mosquitoes with 3.3 log10 PFU/ml virus, 100 mosquitoes with 3.7 log10 PFU/ml, and 200 mosquitoes with 4.0 log10 PFU/ml. Results indicate that WNV can be reliably detected by all 4 assays in pools of mosquitoes exceeding 50 specimens, though there is some loss of sensitivity with very large pool sizes. PMID:18240515

  7. DIFFERENTIAL IMPACT OF WEST NILE VIRUS ON CALIFORNIA BIRDS

    PubMed Central

    Wheeler, Sarah S.; Barker, Christopher M.; Fang, Ying; Armijos, M. Veronica; Carroll, Brian D.; Husted, Stan; Johnson, Wesley O.; Reisen, William K.

    2010-01-01

    The strain of West Nile virus (WNV) currently epidemic in North America contains a genetic mutation elevating its virulence in birds, especially species in the family Corvidae. Although dead American Crows (Corvus brachyrhynchos) have been the hallmark of the epidemic, the overall impact of WNV on North America’s avifauna remains poorly understood and has not been addressed thoroughly in California. Here, we evaluate variation by species in the effect of WNV on California birds from 2004 to 2007 by using (1) seroprevalence in free-ranging birds, (2) percentage of carcasses of each species reported by the public that tested positive for WNV, (3) mortality determined from experimental infections, and (4) population declines detected by trend analysis of Breeding Bird Survey (BBS) data. Using Bayesian linear models, we extrapolate trends in BBS data from 1980–2003 (pre-WNV) to 2004–2007 (post-WNV). We attribute significant declines from expected abundance trends in areas supporting epiornitics to WNV transmission. We combine risk assessed from each of the four data sets to generate an overall score describing WNV risk by species. The susceptibility of California avifauna to WNV varies widely, with overall risk scores ranging from low for the refractory Rock Pigeon (Columba livia) through high for the susceptible American Crow. Other species at high risk include, in descending order, the House Finch (Carpodacus mexicanus), Black-crowned Night-Heron (Nycticorax nycticorax), Western Scrub-Jay (Aphelocoma californica), and Yellow-billed Magpie (Pica nuttalli). Our analyses emphasize the importance of multiple data sources in assessing the effect of an invading pathogen. PMID:20589226

  8. Peptide inhibitors of dengue virus and West Nile virus infectivity

    PubMed Central

    Hrobowski, Yancey M; Garry, Robert F; Michael, Scott F

    2005-01-01

    Viral fusion proteins mediate cell entry by undergoing a series of conformational changes that result in virion-target cell membrane fusion. Class I viral fusion proteins, such as those encoded by influenza virus and human immunodeficiency virus (HIV), contain two prominent alpha helices. Peptides that mimic portions of these alpha helices inhibit structural rearrangements of the fusion proteins and prevent viral infection. The envelope glycoprotein (E) of flaviviruses, such as West Nile virus (WNV) and dengue virus (DENV), are class II viral fusion proteins comprised predominantly of beta sheets. We used a physio-chemical algorithm, the Wimley-White interfacial hydrophobicity scale (WWIHS) [1] in combination with known structural data to identify potential peptide inhibitors of WNV and DENV infectivity that target the viral E protein. Viral inhibition assays confirm that several of these peptides specifically interfere with target virus entry with 50% inhibitory concentration (IC50) in the 10 μM range. Inhibitory peptides similar in sequence to domains with a significant WWIHS scores, including domain II (IIb), and the stem domain, were detected. DN59, a peptide corresponding to the stem domain of DENV, inhibited infection by DENV (>99% inhibition of plaque formation at a concentrations of <25 μM) and cross-inhibition of WNV fusion/infectivity (>99% inhibition at <25 μM) was also demonstrated with DN59. However, a potent WNV inhibitory peptide, WN83, which corresponds to WNV E domain IIb, did not inhibit infectivity by DENV. Additional results suggest that these inhibitory peptides are noncytotoxic and act in a sequence specific manner. The inhibitory peptides identified here can serve as lead compounds for the development of peptide drugs for flavivirus infection. PMID:15927084

  9. Ensemble Evaporation Predictions from Remote Sensing in the Nile Basin

    NASA Astrophysics Data System (ADS)

    Bastiaanssen, W. G.; Hofste, R.; Senay, G. B.; Anderson, M. C.; van Dijk, A.; Pelgrum, H.; Seid, A. H.; Miralles, D.; Hurk, B. V. D.; Wada, Y.; Rebelo, L. M.; Smakhtin, V.

    2014-12-01

    Water scarcity is increasing globally and is most evident in arid zones. Most rainfall is evaporated and runoff coefficients of 5 to 10% are common in arid zone river basins. Evaporation is the most important hydrological process, not only because of its magnitude, but also because it can be managed and regulated by withdrawals, irrigation equipment, agricultural practices, land use changes and soil treatments. Hence, evaporation can be modified and the looming water crisis prompt us to think more careful on how water is consumed and the services and benefits we render on return in terms of agricultural production, ecosystem services, hydropower, leisure etc. Several lead research groups have developed global evaporation products, at least for the African continent. Most of these products have a pixel size varying between 1 to 3 km, and this is a reasonable tradeoff between what is technically preferred (evaporation by land use class) and what can be operationally inferred from the newest earth observation satellites (100 to 1000 m pixels with revisit time of 1 to 5 days). The evaporation variability from monthly SSEBop, ALEXI, CMRSET, NBI version of MOD16, GLEAM and LandSAF model outputs for the main land use classes of the Nile will be demonstrated for the period 2005 to 2012. For 2007, there is also an evaporation data set from ETLook available. The largest variabilities occur on irrigated land, open water bodies and flood plains. The evaporation predictions are compared against flux tower data, and the water balance of paired catchments in Ethiopia and Southern Sudan. It is proposed to use ensemble averages and spreads of actual evaporation values for applications in water management, rather than using one single value and one single model. Some first thoughts on ensemble averaging will be provided. Ensemble evaporation values will be applied in the Water Accounting Plus (WA+) system, being a new analytical framework for water resources assessment reporting

  10. Remotely Sensed Terrestrial Water Balance of the Nile Basin

    NASA Astrophysics Data System (ADS)

    Smith, T. T.; Zaitchik, B. F.; Anderson, M. C.; Yilmaz, M. T.; Alo, C. A.; Rodell, M.

    2011-12-01

    Satellite-derived estimates of precipitation, evapotranspiration (ET), and water storage have transformed our understanding of hydrological dynamics at the basin scale. At the same time, the profusion of satellite and model-generated hydrological estimates has demonstrated that there is still considerable uncertainty associated with the quantification of hydrologic states and fluxes at basin scale: the use of different combinations of data products can lead to dramatically different conclusions regarding water balance partitioning as well as variability and trends in water storage. Including multiple independent products in studies of basin-scale hydrology makes it possible to evaluate known uncertainties in satellite estimates of each component of the hydrological cycle, to assess the influence of these uncertainties on our ability to address hydrological questions of interest, and to identify critical data needs for future satellite missions. Here we present results of a basin-scale water balance analyses of the Nile River basin over the time period of 2007-2010. Multiple satellite-derived and model-based precipitation, ET, and terrestrial water storage products are included in order to characterize absolute and relative uncertainties for each variable of the terrestrial water balance equation. Monthly runoff values are estimated as the residual of the basin water balance. These runoff values are then compared with historical river gauge data to assess the utility of each data combination for estimating river flow and flow variability. Tested products include: the Tropical Rainfall Measurement Mission (TRMM) Multisensor Precipitation Analysis and Climate Prediction Center operational Africa Rainfall Estimates (RFE 2) for precipitation; the Atmospheric-Land Exchange Inverse (ALEXI) model and offline Land Surface Models (LSMs) for ET; and Gravity Recovery and Climate Experiment (GRACE) terrestrial water storage anomaly, merged thermal and microwave derived soil

  11. First isolation of West Nile virus from a dromedary camel.

    PubMed

    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

  12. Monitoring of West Nile virus infections in Germany.

    PubMed

    Ziegler, U; Seidowski, D; Angenvoort, J; Eiden, M; Müller, K; Nowotny, N; Groschup, M H

    2012-09-01

    West Nile virus (WNV) is a flavivirus that is maintained in an enzootic cycle between ornithophilic mosquitoes, mainly of the Culex genus, and certain wild bird species. Other bird species like ravens, jays and raptors are highly susceptible to the infection and may develop deadly encephalitis, while further species of birds are only going through subclinical infection. The objective of this study was to continue in years 2009-2011 the serological and molecular surveillance in wild birds in Germany (see Vector Borne Zoonotic Dis. 10, 639) and to expand these investigations for the first time also to sera from domestic poultry and horses collected between 2005 and 2009. All three cohorts function as indicators for the endemic circulation of WNV. The presence of WNV-specific antibodies was detected in all samples by virus neutralization test (VNT), indirect immunofluorescence test (IFT) and/or enzyme-linked immunosorbent assay (ELISA). The presence of WNV genomes was monitored in relevant sera using two qRT-PCRs that amplify lineage 1 and 2 strains. A total of 364 migratory and resident wild bird serum samples (with emphasis on Passeriformes and Falconiformes) as well as 1119 serum samples from domestic poultry and 1282 sera from horses were analysed. With the exception of one hooded crow, antibody carriers were exclusively found in migratory birds, but not in resident birds/domestic poultry or in local horses. Crows are facultative, short-distance winter migrants in Germany. WNV-specific nucleic acids could not be demonstrated in any of the samples. According to these data, there is no convincing evidence for indigenous WNV infections in equines and in wild/domestic birds in Germany. However, since a few years, WNV infections are endemic in other European countries such as Austria, Hungary, Greece and Italy, a state-of-the-art surveillance system for the detection of incursions of WNV into Germany deems mandatory. PMID:22958253

  13. Conservation and Variability of West Nile Virus Proteins

    PubMed Central

    Jung, Keun-Ok; Ramdas, Shweta; Miotto, Olivo; Tan, Tin Wee; Brusic, Vladimir; Salmon, Jerome; August, J. Thomas

    2009-01-01

    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 ≤1). The representation (frequency) of nonamers variant to the predominant peptide at these stable positions was, generally, low (≤10% of the WNV sequences analyzed). Eighty-eight fragments of length 9–29 amino acids, representing ∼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 therapeutic applications, for

  14. Evaluating the Use of Commercial West Nile Virus Antigens as Positive Controls in the Rapid Analyte Measurement Platform West Nile Virus Assay.

    PubMed

    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

  15. Long-persistence blue phosphors

    NASA Technical Reports Server (NTRS)

    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.

  16. Ecological Risk Assessment of Metal Pollution along Greater Cairo Sector of the River Nile, Egypt, Using Nile Tilapia, Oreochromis niloticus, as Bioindicator

    PubMed Central

    Omar, Wael A.; Mikhail, Wafai Z. A.; Abdo, Hanaa M.; Abou El Defan, Tarek A.; Poraas, Mamdouh M.

    2015-01-01

    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. PMID:26617637

  17. SAR Interferometry as a Tool for Monitoring Coastal Changes in the Nile River Delta of Egypt

    NASA Technical Reports Server (NTRS)

    Aly, Mohamed H.; Klein, Andrew G.; Giardino, John R.

    2005-01-01

    The Nile River Delta is experiencing rapid rates of coastal change. The rate of both coastal retreat and accretion in the Eastern Nile Delta requires regular, accurate detection and measurement. Current techniques used to monitor coastal changes in the delta are point measurements and, thus, they provide a spatially limited view of the ongoing coastal changes. SAR interferometry can provide measurements of subtle coastal change at a significantly improved spatial resolution and over large areas (100 sq km). Using data provided by the ERS-1&2 satellites, monitoring can be accomplished as frequently as every 35 days when needed. Radar interferometry is employed in this study to detect segments of erosion and accretion during the 1993-2000 period. The average rates of erosion and accretion in the Eastern Nile Delta are measured to be -11.64 m/yr and +5.12 m/yr, respectively. The results of this interferometric study can be used effectively for coastal zone management and integrated sustainable development for the Nile River Delta.

  18. West Nile Virus Activity--United States, October 13-19, 2004.

    PubMed

    2004-10-22

    During October 13-19, a total of 200 cases of human West Nile virus (WNV) illness were reported from 20 states (Arizona, Arkansas, California, Colorado, Illinois, Indiana, Iowa, Kansas, Maryland, Michigan, Mississippi, Missouri, Nevada, New Mexico, North Carolina, Oklahoma, Pennsylvania, South Dakota, Wisconsin, and Wyoming). PMID:15499683

  19. Vector competence of the stable fly (Diptera: Muscidae)for West Nile virus.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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. ...

  20. Influence of Tricaine Methanesulfonate on Streptococcus agalactiae vaccination of Nile tilapia (Oreochromis niloticus)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  1. Optimizing fish meal-free commercial diets for Nile Tilapia, Oreochromis niloticus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  2. Occurrence of pesticides in fish tissues, water and soil sediment from Manzala Lake and River Nile.

    PubMed

    Osfor, M M; Abd el Wahab, A M; el Dessouki, S A

    1998-02-01

    Pesticides constitute the major source of potential environmental hazard to man and animal as they are present and concentrated in the food chain. This study was conducted on 136 samples of water, sediment and fish for detection and determination of pesticide residues in this ecosystem. Highly significant differences were found in levels of Indian, heptachlor, endrin, dieldrin, P,P'-DDE and propoxur in River Nile water when compared with that of Manzala Lake. Levels of Indian, endrin, malathion and diazinon were significantly higher in soil sediment of Manzala Lake, while the levels of heptachlor, aldrine, P,P'-DDE, DDT, parathion, propoxur and zectran were significantly higher in soil sediment of River Nile. Boury fish of Manzala Lake contained higher levels of heptachlor, aldrin, P,P'-DDE and malathion, while boury fish of River Nile contained a higher level of zectran only. This survey, thus indicated that Manzala Lake and even the River Nile which was used as control are heavily contaminated with chlorinated hydrocarbons (Indian, heptachlor, aldrin, endrin, dieldrin, P,P'-DDE and DDT), organic phosphorus compounds (malathion, dimethoat, diazinon and parathion) and carbamate pesticides (propoxur and zectran). PMID:9584277

  3. West Nile virus isolated from a Virginia opossum (Didelphis virginiana) in northwestern Missouri, USA, 2012.

    PubMed

    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 from Blood Donors, Vertebrates, and Mosquitoes, Puerto Rico, 2007

    PubMed Central

    McElroy, Kate L.; Bessoff, Kovi; Colón, Candimar; Barrera, Roberto; Muñoz-Jordán, Jorge L.

    2009-01-01

    West Nile virus (WNV) was isolated from a human blood donor, a dead falcon, and mosquitoes in Puerto Rico in 2007. Phylogenetic analysis of the 4 isolates suggests a recent introduction of lineage I WNV that is closely related to WNV currently circulating in North America. PMID:19751597

  5. Fecal strings Associated with Streptococcus agalactiae Infection in Nile Tilapia, Oreochromis niloticus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  6. Efficacy of an experimentally inactivated Streptococcus agalactiae vaccine in Nile tilapia (Oreochromis niloticus) reared in Brazil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  7. Detection by Enzyme-Linked Immunosorbent Assay of Antibodies to West Nile virus in Birds

    PubMed Central

    Dupuis, Alan P.; Nicholas, David; Young, Donna; Maffei, Joseph; Kramer, Laura D.

    2002-01-01

    We adapted an indirect immunoglobulin G enzyme-linked immunosorbent assay to facilitate studies of West Nile virus (WNV) and evaluated its application to taxonomically diverse avian species. Anti-WNV antibodies were detected in 23 bird species, including many exotic species, demonstrating its value in studies of WNV epizootiology. PMID:12194778

  8. Anatomy of a river drainage reversal in the Neogene Kivu Nile Rift

    NASA Astrophysics Data System (ADS)

    Holzförster, F.; Schmidt, U.

    2007-07-01

    The Neogene geological history of East Africa is characterised by the doming and extension in the course of development of the East African Rift System with its eastern and western branches. In the centre of the Western Rift Rise Rwanda is situated on Proterozoic basement rocks exposed in the strongly uplifted eastern rift shoulder of the Kivu-Nile Rift segment, where clastic sedimentation is largely restricted to the rift axis itself. A small, volcanically and tectonically controlled depository in northwestern Rwanda preserved the only Neogene sediments known from the extremely uplifted rift shoulder. Those (?)Pliocene to Pleistocene/Holocene fluvio-lacustrine muds and sands of the Palaeo-Nyabarongo River record the influence of Virunga volcanism on the major drainage reversal that affected East Africa in the Plio-/Pleistocene, when the originally rift-parallel upper Nile drainage system became diverted to the East in order to enter the Nile system via Lake Victoria. Sedimentary facies development, heavy mineral distributions and palaeobiological controls, including hominid artefacts, signal a short time interval of <300-350 ka to complete this major event for the sediment supply system of the Kivu-Nile Rift segment.

  9. HYPOXIA INDUCES HSP 70 PRODUCTION IN JUVENILE NILE TILAPIA, OREOCHROMIS NILOTICUS (L.)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Enzyme linked immunosorbent assay (ELISA) was used to determine levels of the inducible heat shock protein 70 (hsp70) in response to prolonged anoxic conditions in juvenile Nile tilapia. This protein was detected in brain, liver, muscle and head kidney. A significant difference between treatments (...

  10. West Nile Virus Documented in Indonesia from Acute Febrile Illness Specimens

    PubMed Central

    Myint, Khin Saw Aye; Kosasih, Herman; Artika, I. Made; Perkasa, Aditya; Puspita, Mita; Ma'roef, Chairin Nisa; Antonjaya, Ungke; Ledermann, Jeremy P.; Powers, Ann M.; Alisjahbana, Bachti

    2014-01-01

    We report the presence of West Nile virus in a cryopreserved, dengue-negative serum specimen collected from an acute fever case on Java in 2004–2005. The strain belongs to genotype lineage 2, which has recently been implicated in human outbreaks in Europe. PMID:24420775

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

    USGS Publications Warehouse

    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.

  12. Spatially explicit West Nile virus risk modeling in Santa Clara County, California

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A previously created Geographic Information Systems model designed to identify regions of West Nile virus (WNV) transmission risk is tested and calibrated in Santa Clara County, California. American Crows that died from WNV infection in 2005 provide the spatial and temporal ground truth. Model param...

  13. Spatially Explicit West Nile Virus Risk Modeling in Santa Clara County, CA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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. Evaluation of the link between gyrodactylosis and streptococcosis of Nile tilapia, Oreochromis niloticus (L.)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Streptococcus iniae and Gyrodactylus niloticus are two common pathogens of cultured Nile tilapia,Oreochromis niloticus. Trials were conducted to study concurrent infection of tilapia by G. niloticus and S. iniae and evaluated whether parasitism in tilapia with Gyrodactylus increased susceptibility ...

  16. Effect of parasitism on vaccine efficacy against Streptococcus iniae in Nile tilapia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  17. Surveillance for West Nile Virus in Clinic-admitted Raptors, Colorado

    PubMed Central

    Kratz, Gail; Edwards, Eric; Scherpelz, Judy; Bowen, Richard; Komar, Nicholas

    2007-01-01

    In 2005, 13.5% of clinic-admitted raptors in northern Colorado tested positive for West Nile virus (WNV). Clinic-admitted–raptor surveillance detected WNV activity nearly 14 weeks earlier than other surveillance systems. WNV surveillance using live raptor admissions to rehabilitation clinics may offer a novel surveillance method and should be considered along with other techniques already in use. PMID:17479898

  18. Mosquitoes and the environment in Nile Delta villages with previous rift valley fever activity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Egypt is affected by serious human and animal mosquito-borne diseases such as Rift Valley fever (RVF). We investigated how potential RVF virus mosquito vector populations are affected by environmental conditions in the Nile Delta region of Egypt by collecting mosquitoes and environmental data from t...

  19. Aggression and mortality among Nile tilapia (Oreochromis niloticus) maintained in the laboratory at different densities

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  20. Trichinella zimbabwensis in wild Nile crocodiles (Crocodylus niloticus) of South Africa.

    PubMed

    La Grange, Louis J; Marucci, Gianluca; Pozio, Edoardo

    2009-04-01

    Recent discovery of Trichinella zimbabwensis in crocodiles from Zimbabwe, Lake Cahora Basa, Mozambique, and from lake Abaja, Ethiopia, prompted strict control measures to curb the possible spread of the infection to humans and also to prevent its introduction to other countries, which were considered free of this pathogen. In 2006, the Chief Directorate Veterinary Services of Mpumalanga Province of South Africa launched a survey to investigate the status of wild and commercial breeding crocodiles in the province. To evaluate if T. zimbabwensis was circulating in the environments where crocodiles are living in South Africa, 9 fish, 36 reptiles (including 27 Nile crocodiles) and 4 mammals have been investigated to detect Trichinella sp. larvae in their muscles. In January 2008, a Nile crocodile from Komatipoort, sampled by means of a tail biopsy, tested positive for Trichinella larvae. In June-July 2008, Trichinella sp. larvae were also detected in four other Nile crocodiles from the Olifants River Gorge. The prevalence of Trichinella infection in the investigated wild Nile crocodiles from South Africa is 38.5%. The larvae were identified as belonging to T. zimbabwensis by multiplex-PCR. These are the first reports of T. zimbabwensis in South Africa and suggest that the distribution area of this parasite species is wider than that believed in the past. PMID:19167165

  1. West Nile Virus Isolated from a Virginia Opossum (Didelphis virginiana) in Northwestern Missouri, USA, 2012

    PubMed Central

    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

    2016-01-01

    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

  2. Early-season avian deaths from West Nile virus as warnings of human infection

    USGS Publications Warehouse

    Guptill, S.C.; Julian, K.G.; Campbell, G.L.; Price, S.D.; Marfin, A.A.

    2003-01-01

    An analysis of 2001 and 2002 West Nile virus (WNV) surveillance data shows that counties that report WNV-infected dead birds early in the transmission season are more likely to report subsequent WNV disease cases in humans than are counties that do not report early WNV-infected dead birds.

  3. Tradeoff Analysis Between Economic Development and Climate Change Adaptation Strategies for River Nile Basin Water Resources

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Recent Intergovernmental Panel on Climate Change (IPCC) briefings have declared that the growing population in the Nile river basin region (about 160 million, or 57% of the entire population of the basin’s ten riparian countries) is at risk of water scarcity. Adjustment strategies in response to cl...

  4. Immune response and host protection of Nile tilapia against parasite Ichthyophthirius multifiliis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ichthyophthirius multifiliis (Ich) is one of the virulent ciliated parasites and causes heavy economic loss in freshwater fish. Two immunization trials were conducted to evaluate host protection of Nile tilapia, Oreochromis niloticus against Ich. Immunizations were done with live theronts or sonicat...

  5. Domestic goose as a model for West Nile virus vaccine efficacy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    West Nile virus (WNV) is an emergent pathogen in the Americas, first reported in New York during 1999, and has since spread across the United States (USA), Central and South America causing neurological disease in humans, horses and some bird species, including domestic geese. No WNV vaccines are li...

  6. Fatal clostridial enterotoxemia (Clostridium glycolicum) in an ornate Nile monitor (Varanus ornatus).

    PubMed

    Bertelsen, Mads F; Weese, J Scott

    2006-03-01

    Enterotoxemia caused by Clostridium glycolicum was identified as the cause of circulatory collapse and death in a female, 3-yr-old, captive-bred ornate Nile monitor (Varanus ornatus). Anaerobic culture of fecal samples from 12 other monitor lizards from the collection failed to demonstrate the presence of this pathogen. PMID:17312813

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

    NASA Astrophysics Data System (ADS)

    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.

  8. A Journey on Three Rivers: The Nile, The Rhine, The Mississippi.

    ERIC Educational Resources Information Center

    Allen, Anita

    1996-01-01

    Focuses on the Nile, the Rhine, and the Mississippi, the greatest rivers of Africa, Europe, and North America, respectively. Highlights the rich diversity of subjects associated with rivers including geography, history, literature, and art. Includes 12 learning activities for each river. (MJP)

  9. Complete genome sequence of a virulent Streptococcus agalactiae strain 138P isolated from diseased Nile tilapia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  10. West Nile virus from blood donors, vertebrates, and mosquitoes, Puerto Rico, 2007.

    PubMed

    Hunsperger, Elizabeth A; McElroy, Kate L; Bessoff, Kovi; Colón, Candimar; Barrera, Roberto; Muñoz-Jordán, Jorge L

    2009-08-01

    West Nile virus (WNV) was isolated from a human blood donor, a dead falcon, and mosquitoes in Puerto Rico in 2007. Phylogenetic analysis of the 4 isolates suggests a recent introduction of lineage I WNV that is closely related to WNV currently circulating in North America. PMID:19751597

  11. Mutation in West Nile Virus Structural Protein prM during Human Infection

    PubMed Central

    Lanciotti, Robert S.; Hindiyeh, Musa; Keller, Nathan; Milo, Ron; Mayan, Shlomo; Mendelson, Ella

    2016-01-01

    A mutation leading to substitution of a key amino acid in the prM protein of West Nile virus (WNV) occurred during persistent infection of an immunocompetent patient. WNV RNA persisted in the patient’s urine and serum in the presence of low-level neutralizing antibodies. This case demonstrates active replication of WNV during persistent infection. PMID:27322782

  12. Mosquito and West Nile virus surveillance in northeast Montana, U.S.A., 2005-2006

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mosquito and West Nile virus surveillance was conducted on a National Wildlife Refuge in northeast Montana, 2005-2006, during which outbreaks of WNV in a colony of American white pelicans (Pelecanus erythrorhynchos Gmelin) resulted in juvenile mortality rates of 30 and 31%. During both years, flood...

  13. Occurrence of West Nile Virus Antibodies in Wild Birds, Horses, and Humans in Poland

    PubMed Central

    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

  14. Mutation in West Nile Virus Structural Protein prM during Human Infection.

    PubMed

    Lustig, Yaniv; Lanciotti, Robert S; Hindiyeh, Musa; Keller, Nathan; Milo, Ron; Mayan, Shlomo; Mendelson, Ella

    2016-09-01

    A mutation leading to substitution of a key amino acid in the prM protein of West Nile virus (WNV) occurred during persistent infection of an immunocompetent patient. WNV RNA persisted in the patient's urine and serum in the presence of low-level neutralizing antibodies. This case demonstrates active replication of WNV during persistent infection. PMID:27322782

  15. West Nile virus isolated from Virginia opossum (Didelphis virginiana) in Northwest Missouri 2012

    DOE PAGESBeta

    Bosco-Lauth, Angela; Harmon, Jessica; Lash, R. Ryan; Weiss, Sonja; Langevin, Stanley; Savage, Harry; Marvin S. Godsey, Jr.; Burkhalter, Kristen; Root, J. Jeffrey; Gidlewski, Thomas; et al

    2014-12-01

    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. Furthermore, sequencing determined that the virus was related to lineage 1a WNV02 strains. We discuss the role of wildlife in WNV disease epidemiology.

  16. Occurrence of West Nile virus antibodies in wild birds, horses, and humans in Poland.

    PubMed

    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. Water in the face of afforestation in the Nile Basin (Invited)

    NASA Astrophysics Data System (ADS)

    Gebrehiwot, S. G.

    2013-12-01

    Abstract The Nile is the longest river in the world with catchment area of more than 3 × 106 km2 that is home to a fast growing population of some 2 × 107 people. The specific runoff of the River Nile is far less than that of other major world rivers. Much of the rain falling on the catchment, ca 86%, is lost to evapotranspiration which in turn account for the relatively low specific runoff. Afforestation in the Nile Basin is one the major developmental activities in Africa with more than 80% the continent's tree plantation located in the basin. National and continental greening programs, biofuel production, land acquisition and carbon trade are some of the reasons behind the large scale afforestation. Given the complex relationship between forests and water availability, afforestation program needs to give proper consideration to their influence on water availability. Background studies in the Basin indicate that the low flow is highly dependent on the availability of grassland and woodland land covers; while the concurrent biofuel plantation and land investments have been carried out in the areas of grasslands and woodlands, as remote sensing analysis shown. The same studies on the Basin, as well as other studies from similar areas elsewhere in the world suggest that forest impacts on hydrology tend to be localized, where there may also be regional climatic impacts. So, afforestation programs in the Nile Basin need to embrace local impacts with special focus to grasslands and woodlands.

  18. Bacterial distribution and tissue targets following experimental Edwardsiella ictaluri infection in nile tilapia Oreochromis niloticus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  19. Utilization of diets containing graded levels of ethanol production co-products by Nile Tilapia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A feeding trial was performed to investigate levels of distillers dried grains with solubles (DDGS) as a supplemental nutrient source for juvenile Nile tilapia Oreochromis niloticus. Six isocaloric (4.43 ± 0.20 kcal/g), isonitrogenous (39.3 ± 0.4% protein) experimental diets were formulated to conta...

  20. Blue enhanced light sources: opportunities and risks

    NASA Astrophysics Data System (ADS)

    Lang, Dieter

    2012-03-01

    Natural daylight is characterized by high proportions of blue light. By proof of a third type of photoreceptor in the human eye which is only sensitive in this spectral region and by subsequent studies it has become obvious that these blue proportions are essential for human health and well being. In various studies beneficial effects of indoor lighting with higher blue spectral proportions have been proven. On the other hand with increasing use of light sources having enhanced blue light for indoor illumination questions are arising about potential health risks attributed to blue light. Especially LED are showing distinct emission characteristics in the blue. Recently the French agency for food, environmental and occupational health & safety ANSES have raised the question on health issues related to LED light sources and have claimed to avoid use of LED for lighting in schools. In this paper parameters which are relevant for potential health risks will be shown and their contribution to risk factors will quantitatively be discussed. It will be shown how to differentiate between photometric parameters for assessment of beneficial as well as hazardous effects. Guidelines will be discussed how blue enhanced light sources can be used in applications to optimally support human health and well being and simultaneously avoid any risks attributed to blue light by a proper design of lighting parameters. In the conclusion it will be shown that no inherent health risks are related to LED lighting with a proper lighting design.

  1. Blue Skies, Coffee Creamer, and Rayleigh Scattering

    ERIC Educational Resources Information Center

    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…

  2. Blue collection bag after ileal diversion.

    PubMed

    Hildreth, T A; Cass, A S

    1978-02-01

    Five children with ileal diversions have shown asymptomatic blue staining of the urine collection bags. A tryptophan derivative (indican) in the urine that oxidizes to indigo blue on exposure to air is thought to be the cause of this benign transient phenomenon. PMID:628994

  3. Delta Blues Scholarship and Imperialist Nostalgia.

    ERIC Educational Resources Information Center

    Nye, William P.

    When Delta blues are considered to be "folk music," the genre is inextricably tied to the neocolonial, sharecropping system of cotton production characteristic of the Mississippi Delta region between the Civil War and World War II. "Imperialist nostalgia," then, arises in accounts which pay primary and positive tribute to blues performances…

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

    NASA Astrophysics Data System (ADS)

    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

  5. Featured Molecules: Ascorbic Acid and Methylene Blue

    NASA Astrophysics Data System (ADS)

    Coleman, William F.; Wildman, Randall J.

    2003-05-01

    The WebWare molecules of the month for May are featured in several articles in this issue. "Arsenic: Not So Evil After All?" discusses the pharmaceutical uses of methylene blue and its development as the first synthetic drug used against a specific disease. The JCE Classroom Activity "Out of the Blue" and the article "Greening the Blue Bottle" feature methylene blue and ascorbic acid as two key ingredients in the formulation of the blue bottle. You can also see a colorful example of these two molecules in action on the cover. "Sailing on the 'C': A Vitamin Titration with a Twist" describes an experiment to determine the vitamin C (ascorbic acid) content of citrus fruits and challenges students, as eighteenth-century sea captains, to decide the best fruit to take on a long voyage. Fully manipulable (Chime) versions of these and other molecules are available at Only@JCE Online.

  6. Elementary theorems regarding blue isocurvature perturbations

    NASA Astrophysics Data System (ADS)

    Chung, Daniel J. H.; Yoo, Hojin

    2015-04-01

    Blue CDM-photon isocurvature perturbations are attractive in terms of observability and may be typical from the perspective of generic mass relations in supergravity. We present and apply three theorems useful for blue isocurvature perturbations arising from linear spectator scalar fields. In the process, we give a more precise formula for the blue spectrum associated with the axion model of Kasuya and Kawasaki [Axion Isocurvature Fluctuations with Extremely Blue Spectrum, Phys. Rev. D 80, 023516 (2009).], which can in a parametric corner give a factor of O (10 ) correction. We explain how a conserved current associated with Peccei-Quinn symmetry plays a crucial role and explicitly plot several example spectra including the breaks in the spectra. We also resolve a little puzzle arising from a naive multiplication of isocurvature expression that sheds light on the gravitational imprint of the adiabatic perturbations on the fields responsible for blue isocurvature fluctuations.

  7. Vulnerability of the Nile Delta coastal areas to inundation by sea level rise.

    PubMed

    Hassaan, M A; Abdrabo, M A

    2013-08-01

    Sea level changes are typically caused by several natural phenomena, including ocean thermal expansion, glacial melt from Greenland and Antarctica. Global average sea level is expected to rise, through the twenty-first century, according to the IPCC projections by between 0.18 and 0.59 cm. Such a rise in sea level will significantly impact coastal area of the Nile Delta, consisting generally of lowland and is densely populated areas and accommodates significant proportion of Egypt's economic activities and built-up areas. The Nile Delta has been examined in several previous studies, which worked under various hypothetical sea level rise (SLR) scenarios and provided different estimates of areas susceptible to inundation due to SLR. The paper intends, in this respect, to identify areas, as well as land use/land cover, susceptible to inundation by SLR based upon most recent scenarios of SLR, by the year 2100 using GIS. The results indicate that about 22.49, 42.18, and 49.22 % of the total area of coastal governorates of the Nile Delta would be susceptible to inundation under different scenarios of SLR. Also, it was found that 15.56 % of the total areas of the Nile Delta that would be vulnerable to inundation due to land subsidence only, even in the absence of any rise in sea level. Moreover, it was found that a considerable proportion of these areas (ranging between 32.32 and 53.66 %) are currently either wetland or undeveloped areas. Furthermore, natural and/or man-made structures, such as the banks of the International Coastal Highway, were found to provide unintended protection to some of these areas. This suggests that the inundation impact of SLR on the Nile Delta is less than previously reported. PMID:23271694

  8. Pathline-calibrated groundwater flow models of Nile Valley aquifers, Esna, upper Egypt

    NASA Astrophysics Data System (ADS)

    Brikowski, Tom H.; Faid, Abdallah

    2006-06-01

    Strongly concentrated agriculture along the River Nile in Egypt, combined with hydrologic changes related to the construction of the Aswan High Dam in the 1970's, has led to increasing salinization and waterlogging of agricultural areas. Successful control and remediation of these problems requires accurate understanding of the shallow Quaternary aquifers within the Nile Valley. While extensive conceptual models have been developed by the Egyptian RIGW, published numerical models have yet to incorporate all features of the conceptual model. In particular, marine affinity of some shallow groundwaters within the valley (Cl -as the predominant anion) indicates significant leakage from deeper Cretaceous aquifers into the shallow Quaternary aquifers, a feature that is not present in current models. In this study, groundwater profile modeling incorporating the bedrock leakage demonstrates that its shallow appearance requires hydraulic separation of surficial from deep-recharged zones of the Quaternary aquifer. This separation occurs near the boundary between reclaimed and traditional agricultural lands, which is also the primary site of waterlogging. Apparently, excessive recharge presumed to occur beneath the reclaimed lands does not penetrate deeply, and therefore might be easily remediated with shallow drains. Profound similarities exist between the Nile Valley salinization cases and the occurrence of shallow 'nuisance water' in desert southwestern U.S. cities (e.g. Las Vegas). The U.S. experience with this problem may provide useful guidance in addressing Nile Valley salinization and waterlogging issues in the future. In general, irrigation-related recharge from the reclaimed lands in the Nile Valley may have a much more localized impact on traditional lands than previously thought.

  9. Metals in Nile perch (Lates niloticus) and suspended particulate matter from Lake Victoria, Tanzania.

    PubMed

    Machiwa, John F

    2005-01-01

    A study was conducted to assess the levels of pollutant metals in suspended particulate matter and Nile perch from Lake Victoria. The metals in particulate matter were determined to ascertain their concentrations at the base of the food chain. Nile perch samples were collected in September 2003 from five major fish processing factories at the shores of Lake Victoria in Mwanza and Musoma. The concentrations of total Hg, Pb, Cd, and Cu were generally low in particulate matter and in most locations were close to or below their limits of detection. The concentrations of Zn were high in suspended particulate matter, the highest being 219.4 +/- 153.0 microg L(-1) found in particulate matter from Nungwe Bay in the southern part of Lake Victoria. Nile perch generally contained low levels of heavy metals; the range for Pb was <0.01-0.08 microg g(-1) ww, Cd was <0.001-0.04 microg g(-1) ww, Cu was 0.01-0.97 microg g(-1) ww, and Zn was <0.01-18.94 microg g(-1) ww. The concentration of total mercury ranged between 31.0 and 684.2 ng g(-1) ww; generally, it was below the Food and Agriculture Organization of the United Nations/World Health Organization (1000 ng total Hg g(-1) ww for piscivorous fish species) maximum allowable level. Indeed, all Nile perch samples that weighed less than 10 kg had less than 200 ng total Hg g(-1) ww and therefore are safe for regular consumption by at-risk groups such as children and pregnant women. Levels of mercury and other heavy metals in Nile perch at present is, therefore, not a severe environmental issue; however, urgent regulatory measures should be taken to minimize metal input into the lake to maintain the current levels in the fish. PMID:16134370

  10. Molecular structure, distribution, and immunology function of TNFSF13B (BAFF) in Nile tilapia (Oreochromis niloticus).

    PubMed

    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

  11. Differential pathogenicity of five Streptococcus agalactiae isolates of diverse geographic origin in Nile tilapia (Oreochromis niloticus L.)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  12. Cytochrome B Analysis of Mosquito Blood Meals: Identifying Wildlife Hosts of West Nile Virus Mosquito Vectors in Wyoming, USA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Female mosquitoes commonly exhibit patterns of blood feeding from vertebrate hosts, a behavior that strongly influences mosquito pathogen infection and transmission. The vertebrate host dynamics of the mosquito transmitted arbovirus, West Nile virus (family Flaviviridae, genus Flavivirus, WNV) in sa...

  13. Cool Stars Sing the Blues

    NASA Astrophysics Data System (ADS)

    Luttermoser, D. G.

    2005-12-01

    A high-dispersion spectral atlas of cool red giant stars in the blue and violet is presented. The spectra were obtained over a six-year time period with the stellar spectrograph of the McMath-Pierce Telescope on Kitt Peak. Both N-type carbon stars and M-type oxygen-rich stars are presented from 3900 to 4600 Å, with the M-type stars containing both semiregular and Mira-type variables. The dominant absorption features in these stars at these wavelength result primarily from neutral metals, especially iron, and the CH and CN diatomic molecules. The Miras also show strong emission lines during some of their pulsation cycle. Many of these emission lines result from fluorescence from the Mg II h & k lines in the UV. For these fluoresced features, comparisons are made between the Miras and the semiregular carbon-rich and oxygen-rich variables. Where the oxygen-rich semiregulars show no hint of fluorescence in these features, the carbon stars show a definite ``filling-in'' of the absorption lines.

  14. Gyrodactylus malalai sp. nov. (Monogenea, Gyrodactylidae) from Nile tilapia, Oreochromis niloticus (L.) and Redbelly tilapia, Tilapia zillii (Gervais) (Teleostei, Cichlidae) in the Lake Turkana, Kenya.

    PubMed

    Přikrylová, Iva; Radim, Blažek; Gelnar, Milan

    2012-06-01

    Gyrodactylus malalai sp. nov. is described from the fin surface of cichlid fishes Oreochromis niloticus (L.) and Tilapia zillii (Gervais) caught in Lake Turkana (Kenya). The new species morphologically resembles Gyrodactylus nyanzae Paperna, 1973, but can be readily distinguished by the shape of the marginal hook sickles and the size of its hamuli. The sequence data of rDNA spanning partial 18S, internal transcribe spacer 1 and 2 and the 5.8S gene is unique within GenBank. Genetically, as most similar Gyrodactylus ergensi Přikrylová, Matějusová, Musilová et Gelnar, 2009 was found (97.5%). Moreover, a specimen of G. cichlidarum from O. niloticus, and a specimen G. ergensi from Sarotherodon galilaeus (L.) were collected during sampling in Kenya. Likewise, additional sampling of O. niloticus from the Blue Nile in Sudan revealed the presence of the newly described species. These findings represent the first records of gyrodactylids in both African countries. PMID:22807048

  15. Host feeding pattern of Culex quinquefasciatus (Diptera: Culicidae) and its role in transmission of West Nile virus in Harris County, Texas.

    PubMed

    Molaei, Goudarz; Andreadis, Theodore G; Armstrong, Philip M; Bueno, Rudy; Dennett, James A; Real, Susan V; Sargent, Chris; Bala, Adilelkhidir; Randle, Yvonne; Guzman, Hilda; Travassos da Rosa, Amelia; Wuithiranyagool, Taweesak; Tesh, Robert B

    2007-07-01

    The vertebrate hosts of 672 blood-engorged Culex quinquefasciatus Say, collected in Harris County, Texas, during 2005, were identified by nucleotide sequencing PCR products of the cytochrome b gene. Analysis revealed that 39.1% had acquired blood from birds, 52.5% from mammals, and 8.3% were mixed avian and mammalian blood meals. Most frequent vertebrate hosts were dog (41.0%), mourning dove (18.3%), domestic cat (8.8%), white-winged dove (4.3%), house sparrow (3.2%), house finch (3.0%), gray catbird (3.0%), and American robin (2.5%). Results are interpreted in conjunction with concurrent avian and mosquito West Nile virus (WNV) surveillance activities in Harris County. We conclude that Cx. quinquefasciatus is an opportunistic feeder and principal mosquito vector of WNV in this metropolitan area; however, transmission by other mosquito species or by other modes of infection, such as ingestion, must account for the high WNV infection rates among local blue jays and American crows. PMID:17620633

  16. Phenological and liver antioxidant profiles of adult Nile tilapia (Oreochromis niloticus) exposed to toxic live cyanobacterium (Microcystis aeruginosa Kützing) cells.

    PubMed

    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

  17. Understanding the hydrologic sources and sinks in the Nile Basin using multisource climate and remote sensing data sets

    NASA Astrophysics Data System (ADS)

    Senay, Gabriel B.; Velpuri, Naga Manohar; Bohms, Stefanie; Demissie, Yonas; Gebremichael, Mekonnen

    2014-11-01

    In this study, we integrated satellite-drived precipitation and modeled evapotranspiration data (2000-2012) to describe spatial variability of hydrologic sources and sinks in the Nile Basin. Over 2000-2012 period, 4 out of 11 countries (Ethiopia, Tanzania, Kenya, and Uganda) in the Nile Basin showed a positive water balance while three downstream countries (South Sudan, Sudan, and Egypt) showed a negative balance. Gravity Recovery and Climate Experiment (GRACE) mass deviation in storage data analysis showed that at annual timescales, the Nile Basin storage change is substantial while over longer time periods, it is minimal (<1% of basin precipitation). We also used long-term gridded runoff and river discharge data (1869-1984) to understand the discrepancy in the observed and expected flow along the Nile River. The top three countries that contribute most to the flow are Ethiopia, Tanzania, and Kenya. The study revealed that ˜85% of the runoff generated in the equatorial region is lost in an interstation basin that includes the Sudd wetlands in South Sudan; this proportion is higher than the literature reported loss of 50% at the Sudd wetlands alone. The loss in runoff and flow volume at different sections of the river tend to be more than what can be explained by evaporation losses, suggesting a potential recharge to deeper aquifers that are not connected to the Nile channel systems. On the other hand, we also found that the expected average annual Nile flow at Aswan is greater (97 km3) than the reported amount (84 km3). Due to the large variations of the reported Nile flow at different locations and time periods, the study results indicate the need for increased hydrometeorological instrumentation of the basin. The study also helped improve our understanding of the spatial dynamics of water sources and sinks in the Nile Basin and identified emerging hydrologic questions that require further attention.

  18. Fatal human eosinophilic meningo-encephalitis caused by CNS co-infection with Halicephalobus gingivalis and West Nile virus.

    PubMed

    Anwar, M A; Gokozan, H N; Ball, M K; Otero, J; McGwire, B S

    2015-10-01

    The saprophytic nematode Halicephalobus is a rare cause of fatal human meningo-encephalitis, and West Nile virus is neurotropic flavivirus implicated in a variety of clinical neurologic syndromes. Here we report a case of rapidly progressive CNS encephalopathy and death. Serologic, immuno-histochemical, histopathologic and nucleic acid studies demonstrate the presence of active Halicephalobus and West Nile virus in the CNS tissue. This is the first reported case of co-infection with these neurotropic pathogens. PMID:26050925

  19. The geomorphological map of Lake Tana basin (Ethiopia)

    NASA Astrophysics Data System (ADS)

    Poppe, Ludwin; Nyssen, Jan; Poesen, Jean; Admasu, Teshager; Dessie, Mekete; Adgo, Enyew; Deckers, Jozef; Frankl, Amaury

    2013-04-01

    The geomorphological map of Lake Tana basin (15 077 km², Nile basin, Ethiopia) was prepared from fieldwork data, maps and satellite data that were processed in a GIS system. It contains four major components: (i) hydrography, (ii) morphology and -metry, (iii) materials and (iv) processes. The scale is 1:500 000. The geomorphological setting of the basin consists of lavas that erupted from fissures or (shield) volcanoes during the Tertiary and Quaternary eras, were uplifted and ultimately sculpted by (mainly water) erosion. Lake Tana emerged by the combination of a lava barrier blocking the Blue Nile to the south and by epirogenetic subsidence. Since the time that the lake reached its maximum extent, extensive floodplains were created, river valleys have been filled with sediment and higher laying topography has been eroded. Today, the lake plays a lesser role in landscape formation because of a decreased lake extent (3041 km² now) as compared to the ancient maximum (6602 km²). Dominant processes today are merely fluvial and denudative. Recent (1886-2010) changes in lake coast are small with exception of the delta of the major feeding river, Gilgel Abay, which increased disproportionally the last 15 years. This indicates a large input of sediment which is mainly due to rivers flowing through Quaternary lavas. The recent sediment input increase is most probably related to human induced land-use changes.

  20. Semiconducting layered blue phosphorus: a computational study.

    PubMed

    Zhu, Zhen; Tománek, David

    2014-05-01

    We investigate a previously unknown phase of phosphorus that shares its layered structure and high stability with the black phosphorus allotrope. We find the in-plane hexagonal structure and bulk layer stacking of this structure, which we call "blue phosphorus," to be related to graphite. Unlike graphite and black phosphorus, blue phosphorus displays a wide fundamental band gap. Still, it should exfoliate easily to form quasi-two-dimensional structures suitable for electronic applications. We study a likely transformation pathway from black to blue phosphorus and discuss possible ways to synthesize the new structure. PMID:24836265

  1. Retinal Effects Of Blue Light Exposure

    NASA Astrophysics Data System (ADS)

    Ham, William T.; Mueller, Harold A.; Ruffolo, J. J.

    1980-10-01

    Recent research has shown that blue light exposure is an important factor in certain types of retinal injury. The mammalian ocular media transmits the spectral band 400-1400 nm to the retina. The short wavelengths (400-550 nm) produce a photochemical or actinic type of damage, while the longer wavelengths (550-1400 nm) produce thermal damage. Distinction between the two types of retinal damage are discussed briefly and the importance of the blue light effect for solar retinitis and eclipse blindness is emphasized. The significance of blue light retinal injury is summarized for various environmental and occupational exposures.

  2. Blue jays nest in an unusual structure

    USGS Publications Warehouse

    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.

  3. Blue outliers among intermediate redshift quasars

    NASA Astrophysics Data System (ADS)

    Marziani, P.; Sulentic, J. W.; Stirpe, G. M.; Dultzin, D.; Del Olmo, A.; Martínez-Carballo, M. A.

    2016-01-01

    [OIII]λ 5007 "blue outliers"—that are suggestive of outflows in the narrow line region of quasars—appear to be much more common at intermediate z (high luminosity) than at low z. About 40~% of quasars in a Hamburg ESO intermediate z sample of 52 sources qualify as "blue outliers" (i.e., quasars with [OIII]λλ 4959,5007 lines showing large systematic blueshifts with respect to rest frame). We discuss major findings on what has become an intriguing field in active galactic nuclei research and stress the relevance of "blue outliers" to feedback and host galaxy evolution.

  4. Effects of habitat on mercury concentrations in fish: a case study of Nile perch (Lates niloticus) in Lake Nabugabo, Uganda.

    PubMed

    Hanna, D E L; Buck, D G; Chapman, L J

    2016-01-01

    This study focused on variation in fish mercury (Hg) concentrations in 185 Nile perch (Lates niloticus) samples collected across four different habitat types in Lake Nabugabo, Uganda, a tropical lake located proximate to Lake Victoria. We quantified the stomach contents of Nile perch using the % index of relative importance, as well as, nitrogen and carbon isotopic concentrations to assess the role of diet and trophic level on Hg concentrations. In each habitat, we also evaluated a suite of chemical and physical characteristics that are commonly associated with variation in Hg bioavailability in temperate systems. Using linear mixed models and ANOVA, we demonstrate that habitat of capture is an important predictor of Hg concentrations in Nile perch from Lake Nabugabo and that the relationship between habitat and Hg is size and diet dependent. Nile perch diet as well as dissolved oxygen concentration and pH were also correlated with observed differences in fish Hg. Overall, Hg concentrations in Nile perch were all well below the WHO/FAO recommended guideline of 500 ng/g (mean 13.6 ± 0.4 ng/g wet weight; range 4.9 and 29.3 ng/g wet weight). This work contributes to a growing awareness of intra-lake divergence in Nile perch, as well as, divergence in Hg concentrations between varying aquatic habitat types, particularly wetlands. PMID:26520435

  5. Optimization of a Nile Red method for rapid lipid determination in autotrophic, marine microalgae is species dependent.

    PubMed

    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. PMID:26388510

  6. Hydro-environmental status and soil management of the River Nile Delta, Egypt

    NASA Astrophysics Data System (ADS)

    Elewa, H. H.; El Nahry, A. H.

    2009-04-01

    The sea level rise has its own-bearing on the coastal recession and hydro-environmental degradation of the River Nile Delta. Attempts are made here to use remote sensing to detect the coastal recession in some selected parts and delineating the chemistry of groundwater aquifers and surface water, which lie along south-mid-northern and coastal zone of the Nile Delta. Eight water samples from groundwater monitoring wells and 13 water samples from surface water were collected and analyzed for various hydrochemical parameters. The groundwater samples are classified into five hydrochemical facies on Hill-Piper trilinear diagram based on the dominance of different cations and anions: facies 1: Ca-Mg-Na-HCO3-Cl-SO4 type I; facies 2: Na-Cl-HCO3 type II; facies 3: Na-Ca-Mg-Cl type III, facies 4: Ca-Na-Mg-Cl-HCO3 type IV and facies 5: Na-Mg-Cl type V. The hydrochemical facies showed that the majority of samples were enriched in sodium, bicarbonate and chloride types and, which reflected that the sea water and tidal channel play a major role in controlling the groundwater chemical composition in the Quaternary shallow aquifers, with a severe degradation going north of Nile Delta. Also, the relationship between the dissolved chloride (Cl, mmol/l), as a variable, and other major ion combinations (in mmol/l) were considered as another criterion for chemical classification system. The low and medium chloride groundwater occurs in southern and mid Nile Delta (Classes A and B), whereas the high and very high chloride (classes D and C) almost covers the northern parts of the Nile Delta indicating the severe effect of sea water intrusion. Other facets of hydro-environmental degradation are reflected through monitoring the soil degradation process within the last two decades in the northern part of Nile Delta. Land degradation was assessed by adopting new approach through the integration of GLASOD/FAO approach and Remote Sensing/GIS techniques. The main types of human induced soil

  7. Prussian Blue as a Prebiotic Reagent

    NASA Astrophysics Data System (ADS)

    Ruiz-Bermejo, M.; Menor-Salván, C.; Osuna-Esteban, S.; Veintemillas-Verdaguer, S.

    2009-12-01

    Ferrocyanide has been proposed as a potential prebiotic reagent and the complex salt Prussian Blue, Fe4[Fe(CN)6]3, might be an important reservoir of HCN, in the early Earth. HCN is considered the main precursor of amino acids and purine and pyrimidine bases under prebiotic conditions. Recently, we observed the formation of Prussian Blue in spark discharge experiments using saline solutions of ferrous chloride, FeCl2. Using Prussian Blue as starting material in ammonium suspensions, we obtained organic compounds containing nitrogen. These results seem to indicate that Prussian Blue could have been first, a sink of HCN, and then in subsequent reactions, triggered by pH fluctuations, it might have lead to organic life precursors.

  8. Blue Origin Conducts Pad Escape Test

    NASA Video Gallery

    Blue Origin conducted a successful pad escape test Oct. 19 at the company's West Texas launch site, firing its pusher escape motor and launching a full-scale suborbital crew capsule from a simulate...

  9. Blue Ribbon Panel Report - BRP - Cancer Moonshot

    Cancer.gov

    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.

  10. Blue Origin Tests BE-3 Engine

    NASA Video Gallery

    Blue Origin successfully fires the thrust chamber assembly for its new 100,000 pound thrust BE-3 liquid oxygen, liquid hydrogen rocket engine. As part of the company's Reusable Booster System (RBS)...

  11. Blue Ribbon Panel 2016 Video Playlist

    Cancer.gov

    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.

  12. Blue Ribbon Commission Tour of Hanford Site

    ScienceCinema

    Paul Saueressig

    2010-09-01

    The Blue Ribbon Commission on America's Nuclear Future toured the Department of Energy's Hanford Site on July 14, 2010. Commission members, invited guests, and members of the public visited facilities that store high-level, radioactive waste.

  13. Blue irradiance intercomparison in the medical field

    NASA Astrophysics Data System (ADS)

    Ferreira, Antonio F. G.

    2012-10-01

    This work presents the results of a blue irradiance intercomparison among industrial laboratories of medical devices companies. This intercomparison aims to support the metrological issues of medical equipment manufactures regarding the blue irradiance infant phototherapy equipment requirements on the international standard IEC 60601-2-50:2000. The results showed a low agreement of participants' measurements according to normalized error criterion. The major explanation for this result is associated to an incorrect equipment choice and long recalibration period.

  14. Studies on plasma processing of blue dust

    NASA Astrophysics Data System (ADS)

    Samal, S. K.; P, Sindhoora L.; Mishra, S. C.; Mishra, B.

    2015-02-01

    Plasma smelting was carried out using blue dust and petroleum coke mixtures for five different compositions. By altering percentage of reductant and type of plasma forming gas, recovery rate and degree of metallization were calculated in order to examine the extent of reduction of blue dust. The products were characterized by XRD and optical microscopy techniques. The results of these investigations exhibited that highest degree of metallization and recovery rate of about 98% and 86% respectively, were achieved for nitrogen plasma smelted products.

  15. Barium Enhancement in NGC 6819 Blue Stragglers

    NASA Astrophysics Data System (ADS)

    Milliman, Katelyn; Mathieu, Robert D.; Schuler, Simon C.

    2015-01-01

    Possible formation pathways for blue straggler stars include mergers in hierarchical triple systems, stellar collisions during dynamical encounters, and mass transfer from a giant companion. Extensive work on the blue stragglers in the old open cluster NGC 188 (7 Gyr) has led to exciting discoveries including a binary secondary mass distribution peaked at 0.5 MSolar and the detection of three young white dwarf binary companions. These indicate that mass transfer from an asymptotic giant branch star is the dominant mechanism for blue straggler formation in open clusters. Such mass transfer events should pollute the surface abundance of the blue straggler with nucleosynthesis products from the evolved donor. The other formation pathways, mergers and collisions, are predicted to produce no such enhancements. In an effort to move beyond NGC 188 and into other open clusters we present the first results of a surface abundance study of the blue stragglers in the intermediate-aged open cluster NGC 6819 (2.5 Gyr) using the Hydra multi-object spectrograph on the WIYN 3.5 m telescope. This part of our study centers on the s-process element barium as a tracer of formation via mass transfer. We compare the blue straggler surface abundance of barium to that of a sample of main-sequence stars in NGC 6819 and find multiple blue stragglers with anomalous abundances. Surprising, most of the blue stragglers with barium anomalies show no radial-velocity evidence for a companion. We gratefully acknowledge funding from the National Science Foundation under grant AST- 0908082 and the Wisconsin Space Grant Consortium.

  16. Axion isocurvature fluctuations with extremely blue spectrum

    SciTech Connect

    Kasuya, Shinta; Kawasaki, Masahiro

    2009-07-15

    We construct an axion model for generating isocurvature fluctuations with blue spectrum, n{sub iso}=2-4, which is suggested by recent analyses of admixture of adiabatic and isocurvature perturbations with independent spectral indices, n{sub ad}{ne}n{sub iso}. The distinctive feature of the model is that the spectrum is blue at large scales while scale invariant at small scales. This is naturally realized by the dynamics of the Peccei-Quinn scalar field.

  17. Stylish or safe blue-block eyewear

    NASA Astrophysics Data System (ADS)

    Ciosek, Jerzy

    1998-10-01

    The subject of modern, save and stylish eyewear is entertaining not only to people with unwell eyesight. Many people use glasses with anti-UV or blue-block coatings, glasses for driving or working with a computer. There were investigated the blue-block eyewear. There were analyzed reflected radiation at 300 - 400 nm wavelengths with cross- incidence. The traditional eyewear with classical or stylish frame may not protect sight against the UV radiation.

  18. MitoBlue: a nontoxic and photostable blue-emitting dye that selectively labels functional mitochondria.

    PubMed

    Sánchez, Mateo I; Martínez-Costas, José; Mascareñas, José L; Vázquez, M Eugenio

    2014-12-19

    We report the discovery of a fluorogenic dye, N(1),N(3)-di(2-aminidonaphthalen-6-yl) propane-1,3-diamine, MitoBlue, which selectively stains functional mitochondria while displaying low toxicity, bright blue emission, and high resistance to photobleaching. Additionally, we show that a biotin-labeled MitoBlue derivative can be used as a handle for the delivery of streptavidin-tagged species to the mitochondria. PMID:25325672

  19. MitoBlue: A Nontoxic and Photostable Blue-Emitting Dye That Selectively Labels Functional Mitochondria

    PubMed Central

    2014-01-01

    We report the discovery of a fluorogenic dye, N1,N3-di(2-aminidonaphthalen-6-yl) propane-1,3-diamine, MitoBlue, which selectively stains functional mitochondria while displaying low toxicity, bright blue emission, and high resistance to photobleaching. Additionally, we show that a biotin-labeled MitoBlue derivative can be used as a handle for the delivery of streptavidin-tagged species to the mitochondria. PMID:25325672

  20. Blue-white screening liquid can eliminate false positives in blue-white colony screening.

    PubMed

    Zhang, Y S

    2016-01-01

    Although blue-white screening based on α-complementation has been widely used in the screening of genetically modified bacteria, only a single blue-white screening is typically not enough to eliminate false positives. Sometimes, a secondary blue-white screening for the target colonies is required. In this study, two methods were used to investigate the feasibility of secondary blue-white screening for target colonies on lysogeny broth (LB)-ampicillin agar plates. The first method consisted of covering the target colonies grown on LB-ampicillin plate medium with a sterilized filter paper soaked in a solution of 60 μL 20 mg/mL X-gal and 8 μL 20% IPTG. The second method was that blue and white colonies were randomly selected from the blue-white screening plate medium and then re-streaked onto the blue-white screening medium. The colonies were then treated by two methods and incubated at 37°C for 12 h. The results showed that some of the white colonies treated by the two methods showed results similar to the colonies grown on the blue-white screening medium. These results indicate that the target colonies grown on blue-white screening medium can still be used to carry out a secondary blue-white screening. Thus, a blue-white screening liquid was successfully developed. Using the blue-white screening liquid, false positives can be eliminated directly based on the color of the target colonies. This will greatly improve the screening efficiency of positive clones and has important practical implications. PMID:27323169

  1. Blue space geographies: Enabling health in place.

    PubMed

    Foley, Ronan; Kistemann, Thomas

    2015-09-01

    Drawing from research on therapeutic landscapes and relationships between environment, health and wellbeing, we propose the idea of 'healthy blue space' as an important new development Complementing research on healthy green space, blue space is defined as; 'health-enabling places and spaces, where water is at the centre of a range of environments with identifiable potential for the promotion of human wellbeing'. Using theoretical ideas from emotional and relational geographies and critical understandings of salutogenesis, the value of blue space to health and wellbeing is recognised and evaluated. Six individual papers from five different countries consider how health can be enabled in mixed blue space settings. Four sub-themes; embodiment, inter-subjectivity, activity and meaning, document multiple experiences within a range of healthy blue spaces. Finally, we suggest a considerable research agenda - theoretical, methodological and applied - for future work within different forms of blue space. All are suggested as having public health policy relevance in social and public space. PMID:26238330

  2. Blue-phase liquid crystal droplets

    PubMed Central

    Martínez-González, José A.; Zhou, Ye; Rahimi, Mohammad; Bukusoglu, Emre; Abbott, Nicholas L.; de Pablo, Juan J.

    2015-01-01

    Blue phases of liquid crystals represent unique ordered states of matter in which arrays of defects are organized into striking patterns. Most studies of blue phases to date have focused on bulk properties. In this work, we present a systematic study of blue phases confined into spherical droplets. It is found that, in addition to the so-called blue phases I and II, several new morphologies arise under confinement, with a complexity that increases with the chirality of the medium and with a nature that can be altered by surface anchoring. Through a combination of simulations and experiments, it is also found that one can control the wavelength at which blue-phase droplets absorb light by manipulating either their size or the strength of the anchoring, thereby providing a liquid–state analog of nanoparticles, where dimensions are used to control absorbance or emission. The results presented in this work also suggest that there are conditions where confinement increases the range of stability of blue phases, thereby providing intriguing prospects for applications. PMID:26460039

  3. Safe thyroidectomy with intraoperative methylene blue spraying

    PubMed Central

    2012-01-01

    Background We aimed to minimalize operative complications by spraying of methylene blue stain on thyroid glands and the perithyroidal area. Material and methods The intra-operative methylene blue spraying technique was used prospectively on a total of 56 patients who had undergone primary (not recurrent) thyroid surgery for a variety of thyroid diseases. Bilateral total thyroidectomy was performed in all cases. After superior but before inferior pole ligation, 0.5ml of methylene blue was sprayed over the thyroid lobe and perilober area. Tissues, especially parathyroides, the recurrent laryngeal nerve, and the inferior thyroid artery, were identified and evaluated. Results Recurrent laryngeal nerve and arteries were not stained and thus they remained white in all cases while all other tissues were stained blue. Within three minutes parathyroid glands washed out the blue stain and the original yellow color was regained. Thyroid tissue wash-out time was not less than 15 minutes; perithyroideal muscles, tendinous and lipoid structures took no less than 25 minutes. Conclusion The safety of intravascular methylene blue guidance on thyroid surgery is known. This research demonstrates the effectiveness of the spraying technique, a new technique which ensures not only identification of parathyroid glands within three minutes, but also identification of recurrent laryngeal nerves and inferior thyroid arteries. PMID:23148801

  4. New insights into hydrologic sources and sinks in the Nile Basin: A multi-source satellite data analysis

    NASA Astrophysics Data System (ADS)

    Senay, G. B.; Velpuri, N. M.; Bohms, S.; Demissie, Y.; Gebremichael, M.

    2014-12-01

    The Nile River is the longest in the world with a length of 6,800 km. However, the contrast between the length of the river or the size of the basin and the comparatively small volume of basin runoff generated is a unique feature of the Nile Basin. Due to non-availability of in-situ hydrologic data, we do not clearly understand the spatial distribution of hydrologic sources and sinks and how much they control input-output dynamics? In this study, we integrated satellite-derived precipitation, and modeled evapotranspiration data (2000-2012) to describe spatial variability of hydrologic sources and sinks in the Nile Basin. We also used long-term gridded runoff and river discharge data (1869-1984) to understand the discrepancy in the observed and expected flow along the Nile River. Results indicate that over 2000-2012 period, 4 out of 11 countries (Ethiopia, Tanzania, Kenya, and Uganda) in the Nile basin showed a positive water balance while three downstream countries (South Sudan, Sudan, and Egypt) showed a negative balance. The top three countries that contribute most to the flow are Ethiopia, Tanzania and Kenya. The study revealed that ~85% of the runoff generated in the Equatorial region is lost in an inter-station basin that includes the Sudd wetlands in South Sudan; this proportion is higher than the reported loss of 50% at the Sudd wetlands alone. The loss in runoff and flow volume at different sections of the river tend to be more than what can be explained by evaporation losses, suggesting a potential recharge to deeper aquifers that are not connected to the Nile channel systems. On the other hand, we also found that the expected average annual Nile flow at Aswan is larger (97 km3) than the reported amount (84 km3). Gravity Recovery and Climate Experiment (GRACE) mass deviation in storage data analysis showed that at annual time-scales, the Nile Basin shows storage change is substantial while over longer-time periods, it is minimal (<1% of basin precipitation

  5. Molecular Epidemiology and Evolution of West Nile Virus in North America

    PubMed Central

    Mann, Brian R.; McMullen, Allison R.; Swetnam, Daniele M.; Barrett, Alan D. T.

    2013-01-01

    West Nile virus (WNV) was introduced to New York in 1999 and rapidly spread throughout North America and into parts of Central and South America. Displacement of the original New York (NY99) genotype by the North America/West Nile 2002 (NA/WN02) genotype occurred in 2002 with subsequent identification of a novel genotype in 2003 in isolates collected from the southwestern Unites States region (SW/WN03 genotype). Both genotypes co-circulate to date. Subsequent WNV surveillance studies have confirmed additional genotypes in the United States that have become extinct due to lack of a selective advantage or stochastic effect; however, the dynamic emergence, displacement, and extinction of multiple WNV genotypes in the US from 1999–2012 indicates the continued evolution of WNV in North America. PMID:24135819

  6. Subsidence in the northeastern nile delta: rapid rates, possible causes, and consequences.

    PubMed

    Stanley, D J

    1988-04-22

    Holocene fluvial and marine deposits have accumulated in a graben-like structure on the northeastern margin of the Nile delta. This part of the delta, which includes Lake Manzala, Port Said, and the northern Suez Canal, has subsided rapidly at rates of up to 0.5 centimeter per year since about 7500 years ago. This subsidence has diverted at last four major distributaries of the Nile River into this region. The combined effects of continued subsidence and sea level rise may flood a large part of the northern delta plain by as much as 1 meter by the year 2100. The impact of continued subsidence, now occurring when sediment input along the coast has been sharply reduced because of the Aswan High Dam, is likely to be substantial, particularly in the Port Said area and as far inland as south of Lake Manzala. PMID:17784071

  7. Investigation of acute toxicity of chlorpyrifos-methyl on Nile tilapia (Oreochromis niloticus L.) larvae.

    PubMed

    Gül, Ali

    2005-04-01

    Chlorpyrifos-methyl, a wide-spectrum organophosphorus insecticide and potential toxic pollutant contaminating aquatic ecosystems, was investigated for acute toxicity. Larvae of the freshwater fish Nile tilapia (Oreochromis niloticus L.) were selected for the bioassay experiments. The experiments were repeated three times and the 96 h LC50 was determined for the larvae. The static test method for assessing acute toxicity was used. Water temperature was maintained at 25+/-1 degrees C. In addition, behavioral changes at each chlorpyrifos-methyl concentration were observed for the individual fish. Data obtained from the chlorpyrifos-methyl acute toxicity tests were evaluated using Finney's probit analysis statistical method. The 96 h LC50 value for Nile tilapia larvae was calculated to be 1.57 mg/l. PMID:15722087

  8. Evaluating red-cockaded woodpeckers for exposure to West Nile Virus and blood parasites

    USGS Publications Warehouse

    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.

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

    PubMed Central

    Chevalier, Véronique; Tran, Annelise; Durand, Benoit

    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 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

  10. Surveillance for West Nile Virus in American White Pelicans, Montana, USA, 2006–2007

    PubMed Central

    Nemeth, Nicole; Hale, Kristina; Lindsey, Nicole; Panella, Nicholas; Komar, Nicholas

    2010-01-01

    West Nile virus (WNV)–associated deaths of American white pelican (Pelecanus erythrorhynchos) chicks have been recognized at various nesting colonies in the United States since 2002. We evaluated American white pelican nesting colonies in Sheridan County, Montana, USA, for an association between WNV-positive pelican carcasses and human West Nile neuroinvasive disease. Persons in counties hosting affected colonies had a 5× higher risk for disease than those in counties with unaffected colonies. We also investigated WNV infection and blood meal source among mosquitoes and pelican tissue type for greatest WNV detection efficacy in carcasses. WNV-infected Culex tarsalis mosquitoes were detected and blood-engorged Cx. tarsalis contained pelican DNA. Viral loads and detection consistency among pelican tissues were greatest in feather pulp, brain, heart, and skin. Given the risks posed to wildlife and human health, coordinated efforts among wildlife and public health authorities to monitor these pelican colonies for WNV activity are potentially useful. PMID:20202414

  11. Surveillance for West Nile virus in American white pelicans, Montana, USA, 2006-2007.

    PubMed

    Johnson, Gregory; Nemeth, Nicole; Hale, Kristina; Lindsey, Nicole; Panella, Nicholas; Komar, Nicholas

    2010-03-01

    West Nile virus (WNV)-associated deaths of American white pelican (Pelecanus erythrorhynchos) chicks have been recognized at various nesting colonies in the United States since 2002. We evaluated American white pelican nesting colonies in Sheridan County, Montana, USA, for an association between WNV-positive pelican carcasses and human West Nile neuroinvasive disease. Persons in counties hosting affected colonies had a 5x higher risk for disease than those in counties with unaffected colonies. We also investigated WNV infection and blood meal source among mosquitoes and pelican tissue type for greatest WNV detection efficacy in carcasses. WNV-infected Culex tarsalis mosquitoes were detected and blood-engorged Cx. tarsalis contained pelican DNA. Viral loads and detection consistency among pelican tissues were greatest in feather pulp, brain, heart, and skin. Given the risks posed to wildlife and human health, coordinated efforts among wildlife and public health authorities to monitor these pelican colonies for WNV activity are potentially useful. PMID:20202414

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

    NASA Astrophysics Data System (ADS)

    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.

  13. An overview on selected Middle Miocene slope channel complexes, offshore east Nile Delta of Egypt

    NASA Astrophysics Data System (ADS)

    F. Sharaf, Essam; Khaled, Khaled A.; Abushady, Ahmed I.

    2015-12-01

    Middle Miocene turbidite channel reservoirs offshore Nile Delta of Egypt are difficult to develop efficiently. The depositional mechanism of these channels defines sand bodies with variable thickness and quality over short distances. Akhen Field is a turbidite high pressure and high temperature reservoir offshore in the East Nile Delta, Egypt. The turbidite deposits at Akhen area reflect varied depositional fabrics from poorly to moderately sorted and non-graded to graded. Well logs and core data suggest at least 3 sand packages in a cyclic pattern. Each package exhibits variable sedimentological and petrophysical properties and forms a separate reservoir, sealed by shale. A conceptual geologic model showing facies geometry based on 3D seismic mapping and core analysis was used for evaluation of the reservoir quality of the Field. Integrating sedimentologic and other subsurface data such as seismic attributes, pressure data, core analysis, was crucial to predict the fluid flow between the different reservoir units.

  14. STS-56 view of freeflying SPARTAN-201 and Earth observation of Nile River,Egypt

    NASA Technical Reports Server (NTRS)

    1993-01-01

    During STS-56, the Shuttle Pointed Autonomous Research Tool for Astronomy 201 (SPARTAN-201), a freeflying payload, is captured as it orbits the Earth above the Nile River Valley in Egypt. This synoptic view taken aboard Discovery, Orbiter Vehicle (OV) 103, reveals the landscapes of the Sinai and the Gulf of Suez on the left and the Qatara Depression on the right. The Nile River Valley and the base of the delta feature are in the center. The leaf-like appearance of El Fayum is clearly seen. The city of Cairo is also easily recognized at the base of the delta. SPARTAN-201 was later captured by OV-103's remote manipulator system (RMS) and returned to Earth with the astronaut crew.

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

    The western bank of the river Nile in the Luxor region (Egypt) separates New Kingdom divine temple complexes in the central axis of the river valley from contemporaneous sites on the desert edge and limestone plateau. The intermediate Nile floodplain features relatively few known archaeological sites, but played an important role in the ancient ritual landscape by connecting the focal region of the living (floodplain) with that of the dead (desert). All Royal Funerary Temple Complexes of the New Kingdom period (1539-1077 BCE), which played a central role in the cosmogonical landscape, are positioned within a confined 3.5 km long strip of land on the western edge of the present floodplain. This preferential location, together with contemporary textual sources and tomb scenes suggesting the nearby presence of canals, have led to the hypothesis that natural and human-made waterways may have once connected the main channel of the Nile with the desert edge. Until the present research took place, no detailed study of pre-existing channel networks existed in the region, leaving a gap in current knowledge on the configuration and use of the ancient floodplain. This study presents the results of a multi-disciplinary study aimed at mapping and dating ancient waterways in the Theban region and aims to find evidence for the natural or human origin of such channels. Boreholes and Electric Resistivity Tomography (ERT) were carried out along a transect that connects the edge of the Holocene floodplain with the current position of the river Nile. Satellite imagery and textual sources were also used to augment the fieldwork. The data indicate the presence of an infilled abandoned channel of the Nile in the western distal part of the current floodplain, adjoining the Funerary Temple complexes. Over 2100 ceramic fragments were analysed from the sedimentary infilling of the silted-up river course, dating it to the end of the New Kingdom, and indicating that the channel and temples

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

    PubMed

    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

  17. 49 CFR 218.23 - Blue signal display.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Blue signal display. 218.23 Section 218.23..., DEPARTMENT OF TRANSPORTATION RAILROAD OPERATING PRACTICES Blue Signal Protection of Workers § 218.23 Blue signal display. (a) Blue signals displayed in accordance with § 218.25, 218.27, or 218.29 signify...

  18. 49 CFR 218.23 - Blue signal display.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Blue signal display. 218.23 Section 218.23..., DEPARTMENT OF TRANSPORTATION RAILROAD OPERATING PRACTICES Blue Signal Protection of Workers § 218.23 Blue signal display. (a) Blue signals displayed in accordance with § 218.25, 218.27, or 218.29 signify...

  19. Interferon-λ restricts West Nile virus neuroinvasion by tightening the blood-brain barrier

    PubMed Central

    Lazear, Helen M.; Daniels, Brian P.; Pinto, Amelia K.; Huang, Albert C.; Vick, Sarah C.; Doyle, Sean E.; Gale, Michael; Klein, Robyn S.; Diamond, Michael S.

    2015-01-01

    Although interferon-λ [also known as type III interferon or interleukin-28 (IL-28)/IL-29] restricts infection by several viruses, its inhibitory mechanism has remained uncertain. We used recombinant interferon-λ and mice lacking the interferon-λ receptor (IFNLR1) to evaluate the effect of interferon-λ on infection with West Nile virus, an encephalitic flavivirus. Cell culture studies in mouse keratinocytes and dendritic cells showed no direct antiviral effect of exogenous interferon-λ, even though expression of interferon-stimulated genes was induced. We observed no differences in West Nile virus burden between wild-type and Ifnlr1−/− mice in the draining lymph nodes, spleen, or blood. We detected increased West Nile virus infection in the brain and spinal cord of Ifnlr1−/− mice, yet this was not associated with a direct antiviral effect in mouse neurons. Instead, we observed an increase in blood-brain barrier permeability in Ifnlr1−/− mice. Treatment of mice with pegylated interferon-λ2 resulted in decreased blood-brain barrier permeability, reduced West Nile virus infection in the brain without affecting viremia, and improved survival against lethal virus challenge. An in vitro model of the blood-brain barrier showed that interferon-λ signaling in mouse brain microvascular endothelial cells increased transendothelial electrical resistance, decreased virus movement across the barrier, and modulated tight junction protein localization in a protein synthesis– and signal transducer and activator of transcription 1 (STAT1)–independent manner. Our data establish an indirect antiviral function of interferon-λ in which noncanonical signaling through IFNLR1 tightens the blood-brain barrier and restricts viral neuroinvasion and pathogenesis. PMID:25904743

  20. Measurement of radioactivity levels in soil in the Nile Delta and middle Egypt.

    PubMed

    Ibrahiem, N M; Abd el Ghani, A H; Shawky, S M; Ashraf, E M; Farouk, M A

    1993-06-01

    Concentrations of radionuclides in surface soil across the Nile Delta, the north coast of Egypt, and Middle Egypt have been measured using a hyperpure germanium spectrometer. The concentrations obtained for 40K, the 232Th series, and the 226Ra series are expressed in Bq kg-1 of dry weight, and the exposure rates are expressed in nGy h-1 of wet weight. The activity concentrations of 137Cs in soil are expressed in Bq m-2. PMID:8491618