WorldWideScience

Sample records for proglacial sedimentation highlights

  1. Sedimentation in arctic proglacial lakes: Mittivakkat Glacier, SE Greenland

    DEFF Research Database (Denmark)

    Hasholt, Bent; Walling, Desmond Eric; Owens, P.N.

    2000-01-01

    lake sedimentation, sediment yields, sediment sources, calcium-137, lead-210, archz, proglacial, Greenland......lake sedimentation, sediment yields, sediment sources, calcium-137, lead-210, archz, proglacial, Greenland...

  2. Streamflow response to glacier melt and related fluvial sediment transport in a proglacial Alpine river system

    Science.gov (United States)

    Morche, D.; Schuchardt, A.; Baewert, H.; Weber, M.; Faust, M.

    2016-12-01

    Glaciers in the European Alps are retreating since the end of the Little Ice Age around 1850. Where the glaciers shrink, they leave unconsolidated sediment stores (moraines, till, glacifluvial deposits). These sediment stores are highly vulnerable for being subsequently eroded and are thus a key variable (source) in the fluvial sediment budget of proglacial areas. The fluvial system in proglacial areas is more or less continuously fed with (fine) sediment by glacial melt water (glacial milk) during the ablation period and infrequently (e.g. during rainstorm events) supplied with sediment by landslides, debris flows, rock fall or fluvial transport from the slopes. A part of the sediment input is temporary stored in intermitted sinks, such as the river bed, bars or braid plains. These storages can be reworked and then become sources for fluvial sediment transport mainly during floods. These sediment transporting processes are highly variable in both, the temporal and spatial scale. A research project has been set up in the Kaunertal valley, Austrian Alps. The presented part of this joint project is focussed on the quantification of recent fluvial sediment dynamics in the proglacial Fagge River below the glacier Gepatschferner. The glacier is located in the Eastern European Alps at the south end of the Kaunertal valley covering an area of 15.7 km² (2012) and is drained by the Fagge River. During the years 2012 to 2015 the Gepatschferner has shown an accelerated glacial retreat leading to the exposure of unconsolidated sediments as well as bedrock areas. The main aim of the presented part of the joint project is the investigation of the fluvial sediment transport rates in the proglacial Fagge River in the Kaunertal valley. Sediment output of the glacial meltwater stream was measured during the ablation periods at a gauging station installed in front of the glacier outlet. Water level was recorded every 15 minutes and discharge measurements were made at different

  3. Proglacial lake sediments – a basis for uninterrupted chronicles of the Holocene glacier variations

    Directory of Open Access Journals (Sweden)

    M. Y. Alexandrin

    2015-01-01

    Full Text Available The article covers the origin of paleolimnological method in glaciology, concerns the theoretical background of the approach, and focuses on the principal methods of analysis of the lake sediments and creating the sedimentary age-depth models. Lake sediments can provide a basis for creating uninterrupted reconstructions of the Holocene glacier variations with high resolution. The fundament of paleolimnological method is based on the differences between glacial and non-glacial components of the bottom sediments of proglacial lakes. The glacial signal in the lake sediments was originally distinguished by measuring the organic content of the sediment (normally with loss-on-ignition and the magnetic properties of the sediment. Subsequent methods of analysis could yield more precision and normally include geochemical composition (with the use of high-resolution scanning x-ray fluorescence analysis, use of biogenic indicators (such as pollen and diatoms contained in the sediment and more. Obtaining the most accurate age of the sediment is a crucial question in subsequent application of the sediment parameters for reconstruction of glacier variability. The article covers various methods of dating the lake sediment – radiocarbon, Cs- and Pb-isotope dating, varve counting. Techniques of creating age-depth models are taken into account. A state-of-the-art application of sedimentary properties in paleoglaciology yields a reconstruction of a former equilibrium line altitude – ELA. The article focuses on the basis of the ELA reconstruction approach. Successful examples of reconstructions of glacier variations based on the lake sediments can be found throughout the majority of the glaciated regions of the planet. The article states the most prominent of them and gives an update on the current progress in paleolimnological research in the Caucasus Mountains.

  4. Glacier retreat and associated sediment dynamics in proglacial areas: a case study from the Silvretta Alps, Austria

    Science.gov (United States)

    Felbauer, Lucia; Pöppl, Ronald

    2016-04-01

    Global warming results in an ongoing retreat of glaciers in the Alps, leaving behind large amounts of easily erodible sediments. In addition, the debuttressing of rock-walls and the decay of permafrost in the high mountain regions facilitates mass movements of potential disastrous consequences, such as rock falls, landslides and debris flows. Therefore, it is highly important to quantify the amount of sediments that are supplied from the different compartments and to investigate how glacial retreat influences sediment dynamics in proglacial areas. In the presented work glacier retreat and associated sediment dynamics were investigated in the Kromer valley (Silvretta Alps, Austria) by analyzing remote sensing data. Glacial retreat from the period of 1950 to 2012 was documented by interpreting aerial photographs. By digitizing the different stages of the glaciers for six time frames, changes in glacier area and length were mapped and quantified. In order to identify, characterize and quantify sediment dynamics in the proglacial areas a high resolution DEM of difference (DoD) between 2007 and 2012 was created and analyzed, further differentiating between different zones (e.g. valley bottom, hillslope) and types of geomorphic processes (e.g. fluvial, gravitational). First results will be presented at the EGU General Assembly 2016.

  5. Particle Size Characteristics of Fluvial Suspended Sediment in Proglacial Streams, King George Island, South Shetland Island

    Science.gov (United States)

    Szymczak, Ewa

    2017-12-01

    In this study, the characterization of particle size distribution of suspended sediment that is transported by streams (Ornithologist Creek, Ecology Glacier Creeks, Petrified Forest Creek, Czech Creek, Vanishing Creek, Italian Creek) in the area of the Arctowski Polish Antarctic Station is presented. During the first period of the summer season, the aforementioned streams are supplied by the melting snow fields, while later on, by thawing permafrost. The water samples were collected from the streams at monthly intervals during the Antarctic summer season (January - March) of 2016. The particle size distribution was measured in the laboratory with a LISST-25X laser diffraction particle size analyser. According to Sequoia Scientific Inc., LISST-25X can measure particle sizes (Sauter Mean Diameter) between 2.50 and 500 μm. The results of particle size measurements were analysed in relation to flow velocity (0.18–0.89 m/s), the cross-sectional parameters of the streams, suspended sediment concentration (0.06–167.22 mg/dm3) and the content of particulate organic matter (9.8–84.85%). Overall, the mean particle size ranged from 28.8 to 136 μm. The grain size of well-sorted sediments ranged from 0.076 to 0.57, with the skewness and kurtosis values varying from -0.1 to 0.4, and from 0.67 to 1.3, respectively. Based on the particle size characteristics of suspended sediment, the streams were divided into two groups. For most of the streams, the sediment was very well sorted, while fine sand and very fine sand were dominant fractions displaying symmetric and platykurtic distributions, respectively. Only in two streams, the suspended sediment consisted of silt-size grains, well or moderately well sorted, with coarse-skewness and mostly mesokurtic distribution. The C-M chart suggested that the transportation processes of suspended sediment included the suspended mode only. The grain-size distribution of suspended sediment was mainly influenced by the stream runoff

  6. Holocene glacier activity on Kerguelen Island: preliminary results from a novel proglacial lake sediment record

    Science.gov (United States)

    Støren, Eivind; Bakke, Jostein; Arnaud, Fabien; Poulenard, Jérôme; Fanget, Bernard; Malet, Emmanuel; Sabatier, Pierre

    2016-04-01

    The Polar-regions are changing rapidly as greenhouse warming is continuing with huge impact on e.g. sea ice extent and snow cover. This change triggers teleconnections to low latitude areas challenging societies and human activity. We have, however, very little quantitative information of past climate in the Polar-regions that can be used to evaluate the potential responses and the response patterns to forcing changes and changes in boundary conditions. Whatever anthropogenic changes may occur in the future, they will be superimposed on, and interact with, natural climate variations due to all the forcing we are aware of. This means we need to better document past climate/environmental variability of the Polar-regions. Especially in the Southern Ocean there are few time series recording past climate due to few suitable land areas and the few Sub-Antarctic Islands is remote and has cumbersome logistics. Continuous terrestrial records from this region are therefore urgently needed for constraining future scenarios from earth system models. Glaciers and ice caps are still ubiquitous in the Polar-regions, although they are rapidly shrinking due to the on-going warming. The continuous sedimentary records produced by glaciers, which are stored in downstream lakes, represent supreme archives of past variability wherefrom quantitative information of key climate system components can be extracted. Kerguelen Island is located within the Antarctic Circumpolar Current and the Southern Westerly wind belt and contains several glaciers and smaller ice caps. Terrestrial archives recording past history of the glaciers at Kerguelen thus have a unique potential to record past changes in oceanic and atmospheric circulation patterns from southern mid-latitudes. Here we present preliminary results from the first distal glacier-fed lake that is sampled from Kerguelen Island. A 2.8 m long sediment core was obtained from Lac Guynemer (121masl.) located at the Peninsule Loranchet at the

  7. Channel morphodynamics on a small proglacial braid plain (Fagge River, Gepatschferner, Austria

    Directory of Open Access Journals (Sweden)

    D. Morche

    2015-03-01

    Full Text Available Braid plains are important sediment stores in high mountains, particularly in the glacier forefields of Alpine glaciers. Proglacial braid plains receive sediment input from glacial meltwater and proglacial sediment sources like moraines and glacio-fluvial deposits. The channel morphodynamics on the braid plains are strongly related to the sediment transport and flow regime of the proglacial river. This study deals with channel morphodynamics on a small proglacial braid plain in the European Alps. It focuses on two different time scales. Decadal channel planform changes were assessed by remote sensing approaches. The recent channel bed changes were investigated by cross-sectional surveys and particle counts in 2013. This study is part of the DFG/FWF funded interdisciplinary research project PROSA (High-resolution measurements of morphodynamics in rapidly changing PROglacial Systems of the Alps.

  8. Short-term geomorphological evolution of proglacial systems

    Science.gov (United States)

    Carrivick, Jonathan L.; Heckmann, Tobias

    2017-06-01

    Proglacial systems are amongst the most rapidly changing landscapes on Earth, as glacier mass loss, permafrost degradation and more episodes of intense rainfall progress with climate change. This review addresses the urgent need to quantitatively define proglacial systems not only in terms of spatial extent but also in terms of functional processes. It firstly provides a critical appraisal of prevailing conceptual models of proglacial systems, and uses this to justify compiling data on rates of landform change in terms of planform, horizontal motion, elevation changes and sediment budgets. These data permit us to produce novel summary conceptual diagrams that consider proglacial landscape evolution in terms of a balance of longitudinal and lateral water and sediment fluxes. Throughout, we give examples of newly emerging datasets and data processing methods because these have the potential to assist with the issues of: (i) a lack of knowledge of proglacial systems within high-mountain, arctic and polar regions, (ii) considerable inter- and intra-catchment variability in the geomorphology and functioning of proglacial systems, (iii) problems with the magnitude of short-term geomorphological changes being at the threshold of detection, (iv) separating short-term variability from longer-term trends, and (v) of the representativeness of plot-scale field measurements for regionalisation and for upscaling. We consider that understanding of future climate change effects on proglacial systems requires holistic process-based modelling to explicitly consider feedbacks and linkages, especially between hillslope and valley-floor components. Such modelling must be informed by a new generation of repeated distributed topographic surveys to detect and quantify short-term geomorphological changes.

  9. Variability of solid load in the proglacial Fagge River, Tyrol (Austria)

    Science.gov (United States)

    Baewert, Henning; Weber, Martin; Faust, Matthias; Morche, David

    2016-04-01

    Glaciers can strongly affect sediment dynamics in high-mountain basins. They receive clastic material from rock walls by gravitational processes of various magnitudes (rock slides to rockfalls) or by subglacial erosion and transport sediments downvalley like a conveyor belt. At the glacier tongue the meltwater with its accompanying river load enters the proglacial system. Fine material is moving in suspension leading to turbid meltwater. The coarse fraction of the meltwater load is rolling or sliding as bedload on the proglacial channel bed. As glaciers are vulnerable to and thus indicators of climate change the sediment transfer systems in Alpine glacier basins will respond as well. Since the end of the Little Ice Age (LIA) around 1850 glacier in the European Alps have been melting down and their front lines have been retreating. Where the glacier ice is gone large amounts unconsolidated sediments are deposited (moraines, glaciofluvial deposits) and can easily be reworked during subsequent rain storms or snowmelt. As a consequence it is of great concern whether more solid load (higher sediment availability) or less solid load (trapping effect of proglacial lakes) is transported in proglacial rivers in the near future. Due to glacier retreat the amount of unconsolidated, sparsely vegetated sediments, which are prone to rapid remobilization, is increasing. Because more of these sediments are available for fluvial sediment transport, it is generally assumed that glacier retreat leads to an increase in sediment discharge from proglacial zones. The main objective of this study is to present a budget of the fluvial sediment transport within the proglacial Fagge River for the observation period 2012 - 2014. This quantification of solid sediment transport is needed for further investigations on the way to a holistic sediment budget for the whole glaciated catchment of the Gepatschferner in Tyrol/Austria.

  10. Assessment of sediment sources throughout the proglacial area of a small Arctic catchment based on high-resolution digital elevation models

    Science.gov (United States)

    Kociuba, Waldemar

    2017-06-01

    The article presents calculations of quantitative modifications of the morphology of selected subsystems of a glacial valley through: (i) identification of the spatial distribution of important sources of sediment, (ii) assessment of the spatiotemporal variety of sediment volume and landform morphology, and (iii) assessment of the role of particular subsystems in sediment distribution. The study involved a comparison of the results of field measurements from 2010 to 2013 performed in the Scott Glacier catchment (10.1 km2) in NW Wedel Jarlsberg Land (Spitsbergen). The assessment of the landform surface changes was performed by means of a precise Terrestrial Laser Scanning (TLS) survey. The applied field and post-processing techniques for oblique laser scanning permitted the acquisition of digital elevation data at a resolution 0.01 m and density > 500 pt m- 2. This allowed the development of a detailed terrain model, and balancing spatial quantitative changes in six research test areas (10,000 m2) located within two subsystems of the catchment in a cascade arrangement. In the alluvial valley-floor subsystem, the survey covered: 1) the glacier terminus, 2) the intramarginal outwash plain, 3) the extramarginal braid-plain and 4) the alluvial fan, and in the slope subsystem: 5) the erosional-depositional slope in the gorge through terminal moraines, and 6) the solifluction slope. Three zones differing in terms of the spatiotemporal dynamics of geomorphic processes were distinguished within the two analysed valley subsystems. In the valley floor subsystem, these are: (i) the zone of basic supply (distribution throughout the melting season) and (ii) the redeposition zone (distribution particularly during floods), and in the slope subsystem: (iii) zone of periodical supply (distributed mainly in periods of increased precipitation and rapid increases in temperature in summer and during snow avalanches in winter). The glacier and the landforms of the channel and valley

  11. Groundwater hydrochemistry in the active layer of the proglacial zone, Finsterwalderbreen, Svalbard

    Science.gov (United States)

    Cooper, R.J.; Wadham, J.L.; Tranter, M.; Hodgkins, R.; Peters, N.E.

    2002-01-01

    Glacial bulk meltwaters and active-layer groundwaters were sampled from the proglacial zone of Finsterwalderbreen during a single melt season in 1999, in order to determine the geochemical processes that maintain high chemical weathering rates in the proglacial zone of this glacier. Results demonstrate that the principle means of solute acquisition is the weathering of highly reactive moraine and fluvial active-layer sediments by supra-permafrost groundwaters. Active-layer groundwater derives from the thaw of the proglacial snowpack, buried ice and glacial bulk meltwaters. Groundwater evolves by sulphide oxidation and carbonate dissolution. Evaporation- and freeze-concentration of groundwater in summer and winter, respectively produce Mg-Ca-sulphate salts on the proglacial surface. Re-dissolution of these salts in early summer produces groundwaters that are supersaturated with respect to calcite. There is a pronounced spatial pattern to the geochemical evolution of groundwater. Close to the main proglacial channel, active layer sediments are flushed diurnally by bulk meltwaters. Here, Mg-Ca-sulphate deposits become exhausted in the early season and geochemical evolution proceeds by a combination of sulphide oxidation and carbonate dissolution. At greater distances from the channel, the dissolution of Mg-Ca-sulphate salts is a major influence and dilution by the bulk meltwaters is relatively minor. The influence of sulphate salt dissolution decreases during the sampling season, as these salts are exhausted and waters become increasingly routed by subsurface flowpaths. ?? 2002 Elsevier Science B.V. All rights reserved.

  12. Magnitude and frequency in proglacial rivers: a geomorphological and sedimentological perspective

    Science.gov (United States)

    Marren, Philip M.

    2005-05-01

    Proglacial fluvial sedimentary systems receive water from a variety of sources and have variable discharges with a range of magnitudes and frequencies. Little attention has been paid to how these various magnitude and frequency regimes interact to produce a distinctive sedimentary record in modern and ancient proglacial environments. This paper reviews the concept of magnitude and frequency in relation to proglacial fluvial systems from a geomorphic and sedimentary perspective rather than a hydrological or statistical perspective. The nature of the meltwater inputs can be characterised as low-magnitude-high-frequency, primarily controlled by ablation inputs from the source glacier, or high-magnitude-low-frequency, primarily controlled by 'exceptional' inputs. The most important high-magnitude-low-frequency inputs are catastrophic outburst floods, often referred to by the term jökulhlaup (Icelandic for glacier-burst). Glacier surges are an additional form of cyclical variation impacting the proglacial environment, which briefly alter the volumes and patterns of meltwater input. The sedimentary consequences of low-magnitude-high-frequency discharges are related to frequent variations in stage, the greater directional variability that sediment will record, and the increased significance of channel confluence sedimentation. In contrast, the most significant characteristics of high-magnitude-low-frequency flooding include the presence of large flood bars and mid-channel 'jökulhlaup' bars, hyperconcentrated flows, large gravel dunes, and the formation of ice-block kettle hole structures and rip-up clasts. Glacier surges result in a redistribution of low-magnitude-high-frequency processes and products across the glacier margin, and small floods may occur at the surge termination. Criteria for distinguishing magnitude and frequency regimes in the proglacial environment are identified based on these major characteristics. Studies of Quaternary proglacial fluvial sediments

  13. Quantitative model of carbon and nitrogen isotope composition to highlight phosphorus cycling and sources in coastal sediments (Toulon Bay, France).

    Science.gov (United States)

    Dang, Duc Huy; Evans, R Douglas; Durrieu, Gael; Layglon, Nicolas; El Houssainy, Amonda; Mullot, Jean-Ulrich; Lenoble, Véronique; Mounier, Stéphane; Garnier, Cédric

    2017-12-21

    Nutrient loadings from either point or non-point sources to the environment are related to the growing global population. Subsequent negative impacts of nutrient loading to aquatic environments requires a better understanding of the biogeochemical cycling and better tools to track their sources. This study examines the carbon (C), nitrogen (N) and phosphorus (P) discharge and cycling in a Mediterranean coastal area from rivers to marine sediments and assesses the anthropogenic contributions. Carbon and N concentrations and isotope compositions in rivers particles, surface sediments, and sediment cores were investigated to build up a quantitative multiple-end-member mixing model for C and N isotopes. This model predicts the contribution of four natural and one anthropogenic sources to the sediments and highlighted the anthropogenic fraction of P based on the relationship with anthropogenic δ15N. Although P is a monoisotopic element and total P concentration has been the sole index to study P loading, this study suggests an alternative approach to differentiate anthropogenic and non-anthropogenic (diagenetic) P, revealed point and non-point sources of P, and the corresponding P loading. Also, the diagenetic P background has been calculated for the 50-cm sediment layer of the whole Bay. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. A late Holocene pollen record from proglacial Oblong Tarn, Mount Kenya.

    Directory of Open Access Journals (Sweden)

    Colin J Courtney Mustaphi

    -elevation temperature reconstruction, which supported the strong influence of uphill pollen transport from montane forest vegetation and association between temperatures and montane vegetation dynamics. Pollen accumulation rates showed some variability related to minerogenic sediment input to the lake. The Oblong Tarn pollen record provides an indication of long term vegetation change atop Mount Kenya showing some decreases in local alpine and ericaceous taxa from 5300-3100 cal yr BP and minor centennial-scale variability of montane taxa from mid elevation forests. The record highlights potentials, challenges and opportunities for the use of proglacial lacustrine sediment to examine vegetation change on prominent mountain massifs.

  15. A late Holocene pollen record from proglacial Oblong Tarn, Mount Kenya.

    Science.gov (United States)

    Courtney Mustaphi, Colin J; Gajewski, Konrad; Marchant, Rob; Rosqvist, Gunhild

    2017-01-01

    reconstruction, which supported the strong influence of uphill pollen transport from montane forest vegetation and association between temperatures and montane vegetation dynamics. Pollen accumulation rates showed some variability related to minerogenic sediment input to the lake. The Oblong Tarn pollen record provides an indication of long term vegetation change atop Mount Kenya showing some decreases in local alpine and ericaceous taxa from 5300-3100 cal yr BP and minor centennial-scale variability of montane taxa from mid elevation forests. The record highlights potentials, challenges and opportunities for the use of proglacial lacustrine sediment to examine vegetation change on prominent mountain massifs.

  16. How quickly do High Arctic coastal environments respond to rapid deglaciation and the paraglacial transformation of proglacial areas? - Answers from Spitsbergen, Svalbard Archipelago

    Science.gov (United States)

    Strzelecki, Matt; Long, Antony; Lloyd, Jerry; Zagórski, Piotr

    2014-05-01

    The coastal zone is one of the most important storage systems for sediments that are eroded and transported by rivers, wind and slope processes from deglacierised valleys and proglacial areas before reaching their final sediment sink (fjords or the open sea. The Svalbard archipelago provides an excellent location to quantify how High Arctic coasts are responding to climate warming and the associated paraglacial landscape transformations. In this paper we summarize the results of several coastal surveys carried out by our research teams along the paraglacial coasts of Spitsbergen during the last decade. We reconstruct the post-Little Ice Age development of selected coastlines in Spitsbergen to illustrate the variable coastal response to paraglacial and periglacial processes activated following the recent retreat of glaciers. Our surveys use aerial photogrammetric and GIS analyses, sedimentological classification of coastal deposits and field-based geomorphological mapping in Kongsfjorden, Billefjorden, Bellsund, Hornsund and Sørkappland. Our results document dramatic changes in sediment flux and coastal response under intervals characterized by a warming climate, retreating local ice masses, a shortened winter sea-ice season and thawing permafrost. The study highlights the need for a greater understanding of the controls on High Arctic coastal geomorphology, especially given the potential for future accelerated warming and sea-level rise.

  17. Black carbon contributes to organic matter in young soils in the Morteratsch proglacial area (Switzerland

    Directory of Open Access Journals (Sweden)

    E. Eckmeier

    2013-03-01

    Full Text Available Most glacier forefields of the European Alps are being progressively exposed since the glaciers reached their maximum expansion in the 1850s. Global warming and climate changes additionally promote the exposure of sediments in previously glaciated areas. In these proglacial areas, initial soils have started to develop so that they may offer a continuous chronosequence from 0 to 150-yr-old soils. The build-up of organic matter is an important factor of soil formation, and not only autochthonous but also distant sources might contribute to its accumulation in young soils and surfaces of glacier forefields. Only little is known about black carbon in soils that develop in glacier forefields, although charred organic matter could be an important component of organic carbon in Alpine soils. The aim of our study was to examine whether black carbon (BC is present in the initial soils of a proglacial area, and to estimate its relative contribution to soil organic matter. We investigated soil samples from 35 sites distributed over the whole proglacial area of Morteratsch (Upper Engadine, Switzerland, covering a chronosequence from 0 to 150 yr. BC concentrations were determined in fine earth using the benzene polycarboxylic acid (BPCA marker method. We found that charred organic matter occurred in the whole area, and that it was a main compound of soil organic matter in the youngest soils, where total Corg concentrations were very low. The absolute concentrations of BC in fine earth were generally low but increased in soils that had been exposed for more than 40 yr. Specific initial microbial communities may profit from this additional C source during the first years of soil evolution and potentially promote soil development in its early stage.

  18. Short term development of a recently deglaciated proglacial slope (Gepatschferner/Tyrol) using SfM and LiDAR surveys

    Science.gov (United States)

    Smithgall, K.; Schuchardt, A.; Faust, M.; Morche, D.

    2015-12-01

    Quantifying sediment fluxes of proglacial regions is an important topic both to advance research, but also regional planning. The overarching goal of this research is to monitor the development of a proglacial slope of the Gepatschferner in the Tryol region of Austria. The Gepatschferner, the second largest glacier in Austria, has been retreating since the maximum of the Little Ice Age in 1850. The constant retreat continually exposes large quantities of glacial till which is then susceptible to hillslope and fluvial transport processes. Typically, data resolution and collection time are proportional; to obtain high resolution spatial datasets require significant fieldwork as well as additional data processing time. While utilization of either terrestrial or airborne LiDAR is one of the most common methods used to determine erosion and deposition of sediment at high resolution, several studies have shown that Structure from Motion photogrammetry is another tool available to generate similar quality data with significantly reduced fieldwork. The objective of this study is to determine the suitability and accuracy of using SfM to increase frequency of observation by comparing to terrestrial laser scanning data to determine the best data collection method to obtain both detailed spatial resolution as well as high temporal resolution for data in a proglacial environment. This study is part of the PROSA (High-resolution measurements of morphodynamics in rapidly changing PROglacial Systems of the Alps) research project.

  19. Sudden disintegration of ice in the glacial-proglacial transition zone of the largest glacier in Austria

    Science.gov (United States)

    Kellerer-Pirklbauer, Andreas; Avian, Michael; Hirschmann, Simon; Lieb, Gerhard Karl; Seier, Gernot; Sulzer, Wolfgang; Wakonigg, Herwig

    2017-04-01

    Rapid deglaciation does not only reveal a landscape which is prone to rapid geomorphic changes and sediment reworking but also the glacier ice itself might be in a state of disintegration by ice melting, pressure relief, crevasse formation, ice collapse or changes in the glacier's hydrology. In this study we considered the sudden disintegration of glacier ice in the glacial-proglacial transition zone of Pasterze Glacier. Pasterze Glacier is a typical alpine valley glacier and covers currently some 16.5 km2 making it to the largest glacier in Austria. This glacier is an important site for alpine mass tourism in Austria related to a public high alpine road and a cable car which enable access to the glacier rather easily also for unexperienced mountaineers. Spatial focus in our research is given on two particular study areas where several ice-mass movement events occurred during the 2015- and 2016-melting seasons. The first study area is a crevasse field at the lower third of the glacier tongue. This lateral crevasse field has been substantially modified during the last two melting seasons particularly because of thermo-erosional effects of a glacial stream which changed at this site from subglacial (until 2015) to glacier-lateral revealing a several tens of meters high unstable ice cliff prone to ice falls of different magnitudes. The second study area is located at the proglacial area. At Pasterze Glacier the proglacial area is widely influenced by dead-ice bodies of various dimensions making this area prone to slow to sudden geomorphic changes caused by ice mass changes. A particular ice-mass movement event took place on 20.09.2016. Within less than one hour the surface of the proglacial area changed substantially by tilting, lateral shifting, and subsidence of the ground accompanied by complete ice disintegration of once-debris covered ice. To understand acting processes at both areas of interest and to quantify mass changes we used field observations, terrain

  20. Constraining Subsurface Structure and Composition Using Seismic Refraction Surveys of Proglacial Valleys in the Cordillera Blanca, Peru

    Science.gov (United States)

    Glas, R. L.; Lautz, L.; McKenzie, J. M.; Mark, B. G.; Baker, E. A.; Aubry-Wake, C.; Somers, L. D.; Wigmore, O.

    2015-12-01

    As tropical glaciers rapidly recede in response to climate change, the storage and discharge of groundwater will play an increasing role in regulating river baseflow, particularly during the dry season, when stream flow is currently sustained predominantly by glacial melt. Little is understood regarding the hydrogeologic processes controlling base flow characteristics of low-gradient proglacial valleys of the Cordillera Blanca in Northwestern Peru, which has the world's highest density of tropical glaciers. To better understand the processes of groundwater storage and discharge in proglacial meadows, we completed seismic refraction surveys in three representative valleys of the Cordillera Blanca range: the Quilcayhuanca, Yanamarey, and Pachacoto valleys. The locations of survey transects were chosen based on locations of previous sediment core sampling, GPR lines, and quantification of groundwater-surface water interaction derived from dye and temperature tracing experiments. The seismic surveys consisted of 48 vertical component geophones with 2.5 m spacing. Across the three representative valleys a total of 15 surveys were conducted, covering a distance of 1800 m in cross, down, and oblique-valley directions. Preliminary interpretation of the seismic refraction data indicates a maximum imaging depth of 16 m below land surface, and a transition from glacio-lacustrine sediments to buried saturated talus at a depth of 6 m in the Quilcayhuanca valley. The organic-rich glacio-lacustrine sediments in the Yanamarey valley have seismic velocities ranging from 300 to 800 m/s and are >16 m in thickness at mid- valley. Weathered metasedimentary bedrock in the Pachacoto valley was imaged at ~5 m below the valley surface, exhibiting a p-wave velocity of 3400 m/s. The knowledge of hydrogeologic structure derived from seismic refraction surveys will provide crucial boundary conditions for future groundwater models of the valleys of the Cordillera Blanca.

  1. Climatic control on extreme sediment transfer from Dokriani Glacier ...

    Indian Academy of Sciences (India)

    The heavy sediment load from the glaciers affects the hydropower generation, irrigation and drinking water supply. Therefore, to understand the sediment delivery from glaciated basins, characteristics and variation of the suspended sediment concentrations in the proglacial meltwater stream, Dokriani Glacier, have been ...

  2. Formation and Demise of an Icing-Dammed Proglacial Lake on Bylot Island, Nunavut, Canada

    Science.gov (United States)

    Blade, M. K.; Moorman, B.

    2016-12-01

    In Sirmilik National Park on Bylot Island, Nunavut, Canada, an icing forms each winter at the terminus of Fountain Glacier. The icing is most likely fed by a spring that discharges year-round through an unfrozen talik within the proglacial permafrost. In the summer, portions of the icing melt as a result of increased solar radiation, warm air temperatures, and an influx of meltwater. In the winter, a proglacial lake often forms dammed by the upvalley glacier, underlying permafrost, and downvalley icing. The objectives of this project were to: 1) characterize water flow through the proglacial area; 2) measure degradation of the icing through July 2014 and its impact on the lake; and 3) infer the 2014 proglacial lake formation history. The methods employed were DGPS mapping of the surficial ice and lake bathymetry, time-lapse photography of the hydrological activity, and dye tracing to identify hydrological connectivity. Results indicate that: 1) water flowed into, out of, and through the proglacial lake area through pathways established during the lake area formation. Water sources feeding the lake include: a spring, supra-glacial runoff, subglacial discharge, lateral stream, terrestrial stream, and meltwater from floating lake ice. 2) Icing degradation was most rapid at the marginal stream contact with running water resulting in a 0.8 metre lowering of lake water level. 3) The proglacial lake formed due to persistence of unfrozen water upvalley of the icing from the groundwater spring continuous water supply.

  3. Origin and Distribution of Methane Entrapped in Calcareous Alpine Proglacial Soil

    Science.gov (United States)

    Zhu, Biqing; Schroth, Martin H.; Henneberger, Ruth; Kübler, Manuel; Zeyer, Josef

    2017-04-01

    Methane (CH4) is an important greenhouse gas. The atmospheric methane concentration has been increasing in recent years, which is caused by imbalance between sources and sinks. Methane has been recently discovered to be entrapped in calcareous Swiss Alpine proglacial soil. This CH4 can be released upon mechanical impact and acidification. However, the amount, distribution and environmental fate of this entrapped CH4 in proglacial environment remain unknown. The entrapped CH4 in proglacial soil may be of modern or ancient origin. Modern origin includes ongoing or recent microbial CH4 production (methanogenesis) in subglacial or proglacial environments. An ancient origin mainly refers to CH4 produced thermogenically. This soil entrapped CH4 might be a common phenomenon along the entire glacial forefield, or it might only be present at few locations and depth. We present results of studies from two Swiss Alpine Glacier catchments, Wildstrubel Glacier (Canton Valais) and the Griessfirn Glacier (Canton Uri). Our main goals were 1) to assess the origin of CH4 entrapped in various glacial environments (subglacial, proglacial and supraglacial, soil and bedrocks) using geochemical and microbiological evidence; 2) to assess the spatial distribution of entrapped CH4. We performed geochemical analysis (CH4 content, gas wetness ([C1]/[C2-C3] alkane ratio), CH4 stable 13C- and 2H-isotopes, TOC) on subglacial, proglacial, and supraglacial soil samples collected from well-aerated and water-logged locations. Geochemical analysis was also selectively conducted on pore-water samples and on rock samples collected from different geological formations along the catchments. We also performed batch incubations on soil samples collected from subglacial, proglacial water-logged and supraglacial zones. In addition, for the aforementioned three types of samples, we also performed molecular analyses targeting the mcrA gene, which encodes the α-subunit of the enzyme methyl-coenzyme M reductase

  4. Pro-glacial soil variability and geomorphic activity - the case of three Swiss valleys

    NARCIS (Netherlands)

    Temme, A.J.A.M.; Lange, de K.

    2014-01-01

    Soils in pro-glacial areas are often approached from a chronosequence viewpoint. In the chronosequence approach, the objective is to derive rates of soil formation from differences in properties between soils of different age. For this reason, in chronosequence studies, soils are sampled in

  5. BBG Highlights

    Data.gov (United States)

    Broadcasting Board of Governors — BBG Highlights is a monthly summary of the BBG's accomplishments and news and developments affecting the Agency's work. Now, for the first time, this monthly update...

  6. Hydrologic exchange and chemical weathering in a proglacial watershed near Kangerlussuaq, west Greenland

    Science.gov (United States)

    Deuerling, Kelly M.; Martin, Jonathan B.; Martin, Ellen E.; Scribner, Cecilia A.

    2018-01-01

    The exchange of proglacial river water with active layer pore water could alter water chemical compositions in glacial outwash plains and oceanic solute fluxes. To evaluate effects of this exchange, we sampled Watson River and adjacent pore water during the 2013 melt season at two sandurs in western Greenland; one in Sandflugtdalen and the other near the confluence with Søndre Strømfjord. We measured temperature, specific conductivity, and head gradients between the river and bank over a week-long period at Sandflugtdalen, as well as sediment hydraulic conductivity and chemical compositions of waters from both sites. Specific conductivity of pore water is four to ten times greater than river water as solutes are concentrated from weathering reactions, cryoconcentration, and evaporation. Pore water compositions are predominantly altered by carbonate dissolution and sulfide mineral oxidation. High concentrations of HCO3 and SO4 result from solute recycling and dissolution of secondary Ca-Mg carbonate/sulfate salts initially formed by near-surface evaporation in the summer and at depth by freeze-in of the active layer and cryoconcentration in the winter. High hydraulic conductivity (10-5 to 10-4 m/s) and diurnal fluctuations of river stage during our study caused exchange of river and pore water immediately adjacent to the river channel, with a net loss of river water to the bank. Pore water >6 m from the river continuously flowed away from the river. Approximately 1-8% of the river discharge through the Sandflugtdalen was lost to the river bank during our 6.75 day study based on calculations using Darcy's Law. Although not sampled, some of this water should discharge to the river during low river stage early and late in the melt season. Elevated pore water solute concentrations in sandurs and water exchange at diurnal and seasonal frequency should impact fluxes of solutes to the ocean, although understanding the magnitude of this effect will require long

  7. Evidence for the assimilation of ancient glacier organic carbon in a proglacial stream food web

    Science.gov (United States)

    Fellman, Jason; Hood, Eran; Raymond, Peter A.; Hudson, J.H.; Bozeman, Maura; Arimitsu, Mayumi L.

    2015-01-01

    We used natural abundance δ13C, δ15N, and Δ14C to compare trophic linkages between potential carbon sources (leaf litter, epilithic biofilm, and particulate organic matter) and consumers (aquatic macroinvertebrates and fish) in a nonglacial stream and two reaches of the heavily glaciated Herbert River. We tested the hypothesis that proglacial stream food webs are sustained by organic carbon released from glacial ecosystems. Carbon sources and consumers in the nonglacial stream had carbon isotope values that ranged from -30‰ to -25‰ for δ13C and from -14‰ to 53‰ for Δ14C reflecting a food web sustained mainly on contemporary primary production. In contrast, biofilm in the two glacial stream sites was highly Δ14C-depleted (-215‰ to 175‰) relative to the nonglacial stream consistent with the assimilation of ancient glacier organic carbon. IsoSource modeling showed that in upper Herbert River, macroinvertebrates (Δ14C = -171‰ to 22‰) and juvenile salmonids (Δ14C = −102‰ to 17‰) reflected a feeding history of both biofilm (~ 56%) and leaf litter (~ 40%). We estimate that in upper Herbert River on average 36% of the carbon incorporated into consumer biomass is derived from the glacier ecosystem. Thus, 14C-depleted glacial organic carbon was likely transferred to higher trophic levels through a feeding history of bacterial uptake of dissolved organic carbon and subsequent consumption of 14C-depleted biofilm by invertebrates and ultimately fish. Our findings show that the metazoan food web is sustained in part by glacial organic carbon such that future changes in glacial runoff could influence the stability and trophic structure of proglacial aquatic ecosystems.

  8. Infrared Imaging and Modeling of Proglacial Stream Temperature in the Cordillera Blanca, Peru

    Science.gov (United States)

    Baker, E. A.; Lautz, L.; McKenzie, J. M.; Aubry-Wake, C.; Somers, L. D.; Wigmore, O.; Glose, A.; Glas, R. L.; Mark, B. G.

    2015-12-01

    In the tropical Andes, glacial meltwater is an important water resource for downstream communities, especially during the dry season. Due to climate change, glacial retreat is accelerating and straining already limited water resources in the region. It is hypothesized that groundwater storage and discharge will play a critical role in sustaining future river flows. To improve our understanding of the hydrologic fluxes in proglacial valleys of the tropical Andes, we monitored a ~1.2 km reach of the Quilcayhuanca River, in the Cordillera Blanca, Peru, using a high resolution infrared (IR) camera and in-stream temperature sensors. We positioned the IR camera on the southern valley wall, 96 m above the valley floor, and collected >700 IR images at 10 minute intervals over 5 days. We deployed 40 temperature sensors along the stream at ~25 m intervals and 10 sensors at additional control points throughout the surrounding valley, recording temperature at 10 minute intervals. Groundwater temperature was recorded in 6 wells in the study area. The reach had diurnal temperature fluctuations from ~4 to 13°C, but did not exhibit large longitudinal temperature differences. Stream temperature profiles within the water column show stream water is well mixed, improving the ability of the IR camera to accurately observe the stream temperature at this research site. Temperature sensors in 4 reach tributaries recorded warmer temperatures than the main channel. The daily temperatures of one tributary fluctuated within the range of the groundwater temperature (~9 to 11°C), while another tributary exhibited a range of ~18°C. A weather station in the study area recorded climate data (air temperature, humidity, wind speed, solar radiation) at 10 minute intervals. We used this field data as input for a spatial and temporal energy balance model of the reach. Our model demonstrates the utility of IR imagery to monitor stream temperatures and improves our understanding of energy fluxes in

  9. Water and Sediment Discharges from a Glacier-covered Basin under Maritime Climate in Kamchatka Peninsula, Russia

    OpenAIRE

    Matsumoto, Takane; Chikita, Kazuhisa A.

    2004-01-01

    In order to clarify the characteristics of water and sediment discharges from glacier-covered basins under maritime climate, hydrological observations were carried out within a drainage basin which contains Koryto Glacier in Kamchatka Peninsula, Russia. Water discharge of a proglacial stream near the glacier terminus varied between 3 and 12 m^3 s^[-1] during the summer of 2000. Variation in suspended sediment concentration was positively correlated with water discharge, and values of sediment...

  10. Competing roles of air temperature and summer precipitation events on proglacial stream discharges in Chhota Shigri Glacier catchment, Indian Himalaya

    Science.gov (United States)

    AL, R.

    2016-12-01

    It has been widely recognized that western Himalayan region depends heavily on glacier and snow melt for its water needs. This is true especially for the Chenab sub-basin and more generally for other sub-catchments of the mighty Indus catering to the water demands of millions of stake holders who depend on this water resource. However, there are very few studies available to understand high altitude glaciated catchments, the climatic controls over their flow regimes, and their dependency on glacier mass balances, mainly because of poor access. Hence, the proglacial stream discharges from Chhota Shigri Glacier, a representative glacier of western Himalayan region has been analyzed for understanding the impact of rising air temperatures and highly variable summer precipitation events on discharges that are sourced majorly from snow melt and glacier wastage. This study, for the first time attempts to understand the factors influencing the interannual, subseasonal, and the diurnal variability observed in this representative catchment over four ablation seasons (2010-2013), by monitoring solar radiation, air temperature, summer precipitation, albedo and transient snow cover. The proglacial discharge is governed by air temperatures and albedo-enhancing summer precipitation events, which also enhances transient snow cover. While, the positive mass balance years gave rise to lesser proglacial discharges in comparison to negative mass balance years, lesser winter accumulation was compensated by the lower ablation resulting summer snowfall events in some years. While rising summer air temperatures give rise to glacier wastage, the role of melting transient snow cover on stream discharge is highly significant, especially for positive mass balance years. The pronounced interannual variations and the decreased proglacial discharge in comparison to 1980s suggest that Chhota Shigri Glacier is possibly wasting its way to reach equilibrium to the changed climatic conditions of the

  11. Development of Adygine glacier complex (glacier and proglacial lakes) and its link to outburst hazard

    Science.gov (United States)

    Falatkova, Kristyna; Schöner, Wolfgang; Häusler, Hermann; Reisenhofer, Stefan; Neureiter, Anton; Sobr, Miroslav; Jansky, Bohumir

    2017-04-01

    Mountain glacier retreat has a well-known impact on life of local population - besides anxiety over water supply for agriculture, industry, or households, it has proved to have a direct influence on glacier hazard occurrence. The paper focuses on lake outburst hazard specifically, and aims to describe the previous and future development of Adygine glacier complex and identify its relationship to the hazard. The observed glacier is situated in the Northern Tien Shan, with an area of 4 km2 in northern exposition at an elevation range of 3,500-4,200 m a.s.l. The study glacier ranks in the group of small-sized glaciers, therefore we expect it to respond faster to changes of the climate compared to larger ones. Below the glacier there is a three-level cascade of proglacial lakes at different stages of development. The site has been observed sporadically since 1960s, however, closer study has been carried out since 2007. Past development of the glacier-lake complex is analyzed by combination of satellite imagery interpretations and on-site measurements (geodetic and bathymetric survey). A glacier mass balance model is used to simulate future development of the glacier resulting from climate scenarios. We used the simulated future glacier extent and the glacier base topography provided by GPR survey to assess potential for future lake formation. This enables us to assess the outburst hazard for the three selected lakes with an outlook for possible/probable hazard changes linked to further complex succession/progression (originating from climate change scenarios). Considering the proximity of the capital Bishkek, spreading settlements, and increased demand for tourism-related infrastructure within the main valley, it is of high importance to identify the present and possible future hazards that have a potential to affect this region.

  12. Mapping Glacier Dynamics and Proglacial Wetlands with a Multispectral UAV at 5000m in the Cordillera Blanca, Peru

    Science.gov (United States)

    Wigmore, O.; Mark, B. G.

    2015-12-01

    The glaciers of the Cordillera Blanca, Peru are rapidly retreating as a result of rising temperatures, transforming the hydrology and impacting the socio-economic and environmental systems of the Rio Santa basin. Documenting the heterogeneous spatial patterns of these changes to understand processes of water storage and flow is hindered by technologic and logistic challenges. Highly complex topography, cloud cover and coarse spatial resolution limit the application of satellite data while airborne data collection remains costly and potentially dangerous. However, recent developments have made Unmanned Aerial Vehicle (UAV) technology a viable and potentially transformative method for studying glacier dynamics and proglacial hydrology. The extreme altitudes (4000-6700m) of the Cordillera Blanca limit the use of 'off the shelf' UAVs. Therefore we developed a low cost multispectral (visible, near-infrared and thermal infrared) multirotor UAV capable of conducting fully autonomous aerial surveys at elevations over 5000m within the glacial valleys of the Cordillera Blanca. Using this platform we have completed repeat aerial surveys (in 2014 and 2015) of the debris covered Llaca Glacier, generating highly accurate 10-20cm DEM's and 5cm orthomosaics using a structure from motion workflow. Analysis of these data reveals a highly dynamic system with some areas of the glacier losing as much as 16m of vertical elevation, while other areas have gained up to 5m of elevation over one year. The magnitude and direction of these changes appears to be associated with the presence of debris free ice faces and meltwater ponds. Additionally, we have mapped proglacial meadow and wetland systems. Thermal mosaics at 10-20cm resolution are providing novel insights into the hydrologic pathways of glacier meltwater including mapping the distribution of artesian springs that feed these wetland systems. The high spatial resolution of these UAV datasets facilitates a better understanding of the

  13. Observations of runoff and sediment and dissolved loads from the Greenland Ice Sheet at Kangerlussuaq, West Greenland, 2007 to 2010

    DEFF Research Database (Denmark)

    Hasholt, Bent; Mikkelsen, Andreas Peter Bech; Nielsen, Morten Holtegaard

    2012-01-01

    Observations from 2007 to 2010 of runoff, sediment and solute delivery from a segment of the Greenland Ice Sheet (GrIS) and the proglacial landscape draining into the fjord at Kangerlussuaq are presented. The observations include at least three jökulhlaups and extreme recordings from 2010...... previously published for 2007 and 2008. The average effective erosion from the catchment was 0.28 mm (min. 0.18 and max. 0.45 mm). The erosion is larger than indicated from most other locations along the GrIS, but in the same order of magnitude as erosion in other glaciated areas at the same latitude, e.......g. Norway. The sandur in the proglacial area acts as a sediment sink for a lot of the sediments from the GrIS....

  14. Monitoring of jökulhlaups and element fluxes in proglacial Icelandic rivers using osmotic samplers

    Science.gov (United States)

    Jones, Morgan T.; Gałeczka, Iwona M.; Gkritzalis-Papadopoulos, Athanasios; Palmer, Martin R.; Mowlem, Matthew C.; Vogfjörð, Kristín; Jónsson, Þorsteinn; Gislason, Sigurður R.

    2015-01-01

    The quantification of volatile emissions from volcanoes is an integral part of understanding magmatic systems, with the exsolution and extent of volcanic degassing having a large impact on the nature of an eruption. Measurements of volatiles have traditionally focused on gas emissions into the atmosphere, but volatiles can also become dissolved in proximal water bodies en route to the surface. Thus the monitoring of rivers draining active volcanic areas can provide insights to identifying changes in activity. This process is particularly important for sub-glacial volcanoes in Iceland, where much of the volatile release is transported within glacial outbreak floods, termed jökulhlaups. Monitoring and characterising these phenomena is hampered by the dependence on spot sampling of stochastic events under challenging field conditions, which often leads to bias in the collected data. A recent technological advance is the osmotic sampler, an electricity-free pump that continuously collects water that can subsequently be divided into time-averaged samples. This technique allows for continued and unsupervised deployment of a sampler for weeks to months, representing a cost-efficient form of chemical monitoring. In this study we deployed osmotic samplers in two rivers in southern Iceland. Skálm is a proglacial river from Mýrdalsjökull glacier and Katla volcano, while Skaftá is a larger drainage system from the western part of Vatnajökull glacier. Both rivers are prone to jökulhlaups from geothermal and volcanic sources, and a small jökulhlaup of geothermal origin occurred during the second deployment in Skaftá in January 2014. The two deployments show that osmotic samplers are capable of delivering accurate chemical data in turbulent conditions for several key elements. Total dissolved fluxes for the deployment at Skaftá are calculated to be Na = 9.9 tonnes/day, Mg = 10.5 t/d, Si = 34.7 t/d, Cl = 11.0 t/d, Ca = 31.6 t/d, DIC = 50.8 t/d, and SO4 = 28.3 t/d, with

  15. Highlights from PHENIX - I

    OpenAIRE

    Franz, A.; Collaboration, for the PHENIX

    2008-01-01

    This contribution highlights recent results from the PHENIX Collaboration at RHIC. It covers global variables, flow and 2--particle correlations. A second contribution in this issue, by T.C.Awes, covers PHENIX results on heavy quarks, leptons and photons.

  16. A long-term multi-proxy record of varved sediments highlights climate-induced mixing-regime shift in a large hard-water lake ~5000 years ago

    Directory of Open Access Journals (Sweden)

    Walter Finsinger

    2014-06-01

    Full Text Available The long-term terrestrial and aquatic ecosystem dynamics spanning between approximately 6200 and 4800 cal BP were investigated using pollen, diatoms, pigments, charcoal, and geochemistry from varved sediments collected in a large stratified perialpine lake, Lago Grande di Avigliana, in the Italian Alps. Marked changes were detected in diatom and pigment assemblages and in sediment composition at ~4900 cal BP. Organic matter rapidly increased and diatom assemblages shifted from oligotrophic to oligo-mesotrophic planktonic assemblages suggesting that nutrients increased at that time. Because land cover, erosion, and fire frequency did not change significantly, external nutrient sources were possibly not essential in controlling the lake-ecosystem dynamics. This is also supported by redundancy analysis, which showed that variables explaining significant amounts of variance in the diatom data were not the ones related to changes in the catchment. Instead, the broad coincidence between the phytoplankton dynamics and rising lake-levels, cooler temperatures, and stronger spring winds in the northern Mediterranean borderlands possibly points to the effects of climate change on the nutrient recycling in the lake by means of the control that climate can exert on mixing depth. We hypothesize that the increased P-release rates and higher organic-matter accumulation rates, proceeded by enhanced precipitation of iron sulphides, were possibly caused by deeper and stronger mixing leading to enhanced input of nutrients from the anoxic hypolimnion into the epilimnion. Although we cannot completely rule out the influence of minor land-cover changes due to human activities, it may be hypothesized that climate-induced cumulative effects related to mixing regime and P-recycling from sediments influenced the aquatic-ecosystem dynamics.

  17. Temperature signal in suspended sediment export from an Alpine catchment

    Science.gov (United States)

    Costa, Anna; Molnar, Peter; Stutenbecker, Laura; Bakker, Maarten; Silva, Tiago A.; Schlunegger, Fritz; Lane, Stuart N.; Loizeau, Jean-Luc; Girardclos, Stéphanie

    2018-01-01

    Suspended sediment export from large Alpine catchments ( > 1000 km2) over decadal timescales is sensitive to a number of factors, including long-term variations in climate, the activation-deactivation of different sediment sources (proglacial areas, hillslopes, etc.), transport through the fluvial system, and potential anthropogenic impacts on the sediment flux (e.g. through impoundments and flow regulation). Here, we report on a marked increase in suspended sediment concentrations observed near the outlet of the upper Rhône River Basin in the mid-1980s. This increase coincides with a statistically significant step-like increase in basin-wide mean air temperature. We explore the possible explanations of the suspended sediment rise in terms of changes in water discharge (transport capacity), and the activation of different potential sources of fine sediment (sediment supply) in the catchment by hydroclimatic forcing. Time series of precipitation and temperature-driven snowmelt, snow cover, and ice melt simulated with a spatially distributed degree-day model, together with erosive rainfall on snow-free surfaces, are tested to explore possible reasons for the rise in suspended sediment concentration. We show that the abrupt change in air temperature reduced snow cover and the contribution of snowmelt, and enhanced ice melt. The results of statistical tests show that the onset of increased ice melt was likely to play a dominant role in the suspended sediment concentration rise in the mid-1980s. Temperature-driven enhanced melting of glaciers, which cover about 10 % of the catchment surface, can increase suspended sediment yields through an increased contribution of sediment-rich glacial meltwater, increased sediment availability due to glacier recession, and increased runoff from sediment-rich proglacial areas. The reduced extent and duration of snow cover in the catchment are also potential contributors to the rise in suspended sediment concentration through

  18. Proglacial vs postglacial depostional environments, the opposing processes that filled the southern North Sea tunnel valleys

    DEFF Research Database (Denmark)

    Moreau, Julien; Huuse, Mads

    prograding north in opposing direction to the former ice flows whose south­ward flowing meltwater excavated the valleys. The first hypothesis, by analogy with some small eskers introduced the concept of backfilling where the eroded sediments upstream is deposited directly below the ice margin, in a conveyor...... challenged by new observations on the architecture of the valleys and their infill sediments which appear to show many similarities in common with deltaic clinoforms observed in the pre­glacial succession of the southern North Sea. The new model states that the incision and the filling of the valleys...... stratigraphic scheme is immense and a long run project, it would be unique for this period in the region. We intend to solve part of the problem by numerically reconstructing the local landscape with the ice sheet and its isostatic depression. This allows to represent a type-sequence helping the understanding...

  19. ATLAS Outreach Highlights

    CERN Document Server

    Cheatham, Susan; The ATLAS collaboration

    2016-01-01

    The ATLAS outreach team is very active, promoting particle physics to a broad range of audiences including physicists, general public, policy makers, students and teachers, and media. A selection of current outreach activities and new projects will be presented. Recent highlights include the new ATLAS public website and ATLAS Open Data, the very recent public release of 1 fb-1 of ATLAS data.

  20. Clinical highlights from Amsterdam

    Directory of Open Access Journals (Sweden)

    Jouke T. Annema

    2016-07-01

    Full Text Available This article contains highlights and a selection of the scientific advances from the Clinical Assembly that were presented at the 2015 European Respiratory Society International Congress in Amsterdam, the Netherlands. The most relevant topics for clinicians will be discussed, covering a wide range of areas including interventional pulmonology, rehabilitation and chronic care, thoracic imaging, diffuse and parenchymal lung diseases, and general practice and primary care. In this comprehensive review, exciting novel data will be discussed and put into perspective.

  1. FY 2016 Research Highlights

    Energy Technology Data Exchange (ETDEWEB)

    2017-03-23

    This fact sheet summarizes the research highlights for the Clean Energy Manufacturing Analysis Center (CEMAC) for Fiscal Year 2106. Topics covered include additive manufacturing for the wind industry, biomass-based chemicals substitutions, carbon fiber manufacturing facility siting, geothermal power plant turbines, hydrogen refueling stations, hydropower turbines, LEDs and lighting, light-duty automotive lithium-ion cells, magnetocaloric refrigeration, silicon carbide power electronics for variable frequency motor drives, solar photovoltaics, and wide bandgap semiconductor opportunities in power electronics.

  2. Highlights from PHENIX

    Science.gov (United States)

    Drees, Axel

    2016-12-01

    This talk presents highlights from the PHENIX experiment. These include results from the beam energy scan at √{sNN} = 7.7 to 200 GeV, yield and anisotropy of low pT direct photon emission in Au+Au, results on the e+e- pair continuum measured with the hadron blind detector (HBD), separation of charm and bottom energy loss using the PHENIX vertex tracker (VTX), and evidence for strongly coupled matter in small systems.

  3. Highlights from ATLAS

    CERN Document Server

    Charlton, D; The ATLAS collaboration

    2013-01-01

    Highlights of recent results from ATLAS were presented. The data collected to date, the detector and physics performance, and measurements of previously established Standard Model processes were reviewed briefly before summarising the latest ATLAS results in the Brout-Englert-Higgs sector, where big progress has been made in the year since the discovery. Finally, selected prospects for measurements including the data from the HL-LHC luminosity upgrade were presented, for both ATLAS and CMS. Many of the results mentioned are preliminary. These proceedings reflect only a brief summary of the material presented, and the status at the time of the conference is reported.

  4. Science Highlights from SOFIA

    Science.gov (United States)

    Young, Erick T.

    2017-06-01

    SOFIA, the Stratospheric Observatory for Infrared Astronomy, is a joint project between NASA and the German Aerospace Center DLR to provide infrared and sub-millimeter observing capabilities to the worldwide astronomical community. With a wide range of instruments that cover both imaging and spectroscopy, SOFIA has produced unique scientific results that could not be obtained with a ground-based facility. In this talk, I will describe highlights from a range of areas in astronomy. A particular strength of SOFIA is high resolution spectroscopy. In the mid-infrared, the instrument EXES has enabled velocity-resolved observations of solar system, interstellar, and star forming regions. The heterodyne spectrometer GREAT has been a particularly productive instrument on SOFIA, with high resolution studies of the gas in the interstellar medium. With its extremely high spectral resolution, GREAT has allowed dynamical studies of clouds and their interactions. I will highlight observations that demonstrate the infall of material in star-forming regions. SOFIA can go to where the science is. This mobility is important for localized events such as occultations. Results from the recent Pluto occultation campaign will be discussed.

  5. Fall Meeting Hydrology Highlights

    Science.gov (United States)

    Bales, Roger

    The AGU 1992 Fall Meeting in San Francisco offered the full range of subjects represented by the Hydrology Section's technical committees. The total number of papers was double the number of just 4 years ago. Sessions were well attended. The following highlights were prepared from material written by session organizers.There were 3 full days of papers on snow, ice, and permafrost. One highlight was the special session on new developments in glacier mass-balance studies, which was organized to compare existing methods and examine new techniques for assessing changes in ice mass of the polar ice sheets and alpine glaciers. Current methods for assessing mass change of the ice sheets include satellite laser altimetry to detect surface-elevation changes, surface-based control volume methods to determine net ice flux in a region, and ice-shelf melting and iceberg calving to determine mass loss from the ice sheet. Using these techniques, it is difficult to tell whether the ice sheet is gaining or losing mass. Methods that use drainage basin inputs/outputs indicate a net mass increase, whereas methods that emphasize oceanographic estimates of ice-shelf melting suggest a net mass decrease and estimates based on satellite altimetry are equivocal.

  6. Scientific Highlights from ROMIC

    Science.gov (United States)

    Lübken, Franz-Josef

    2017-04-01

    The German Federal Ministry of Education and Research (Bundesministerium für Bildung und Forschung, BMBF) has launched a research initiative in 2013/2014 called ROMIC (Role of the Middle Atmosphere in Climate). The aim of ROMIC is to improve our understanding of long term variations in the stratosphere, mesosphere, and lower thermosphere and to investigate their potential role for climate changes in the troposphere. This includes to study coupling mechanisms between various layers and the relative importance of anthropogenic and natural forcing, e. g., by the Sun. Scientists at a total of 15 research institutes in Germany are involved and cover a large range of experimental and theoretical topics relevant for ROMIC. Some scientific highlights from the research projects within ROMIC will be presented.

  7. PSI scientific highlights 2012

    Energy Technology Data Exchange (ETDEWEB)

    Piwnicki, P.; Dury, T. (eds.)

    2013-05-15

    This comprehensive report issued by the Paul Scherrer Institute (PSI) reviews research in various areas carried out by the institute in 2012. Also, the various facilities to be found at the institute are described. Research focus and highlights are discussed. These include work done using synchrotron light, neutrons and muons as well as work done in the particle physics, microtechnology and nanotechnology areas. Further areas of research include biomolecular research, radiopharmacy, radiochemistry and environmental chemistry. Other areas covered include general energy research and work done at the Competence Center for Energy and Mobility CCEM, work done on nuclear energy safety as well as systems analysis in the environmental and energy areas. The report is concluded with facts and figures on the PSI, its Advisory Board and its organisational structures.

  8. PSI scientific highlights 2011

    Energy Technology Data Exchange (ETDEWEB)

    Piwnicki, P. (ed.)

    2012-04-15

    This comprehensive report for the Swiss Federal Office of Energy (SFOE) presents the major highlights of the work done at the Paul Scherrer Institute, Switzerland, in 2011. According to the institute's director, work was concerned with the design and analysis of advanced materials with new functionalities, for application in fields as diverse as communications and energy technology, transportation, construction and medicine. Of particular topical interest are research projects on materials for application in the field of energy, for example for improving batteries for future electrically powered vehicles. Another example is in the field of catalysts. Environmentally harmful compounds, such as nitrogen oxide and sulphur dioxide produced in an engine, are transformed into nontoxic gases through catalytic conversion. Work progress on the SwissFEL installation is noted, including a breakthrough for SwissFEL main Linac C-band accelerating systems. Further topics in relation to the SwissFEL system are noted. Planning of the initial set of experimental stations at the SwissFEL is discussed and close collaboration with growing number of user communities is noted. Cross-Correlation Scattering, and a theoretical framework for this method is being developed and experimentally verified, using artificial nanostructures and synchrotron radiation. Highlights of further research work are discussed, including topics such as Synchrotron light, work done on neutrons and muons, particle physics, micro and nanotechnology as well as on biomolecular research and radiopharmacy. Large research facilities are discussed as is the PSI proton therapy installation. General energy topics are looked at, as are nuclear energy and safety aspects and environmental and energy systems analysis. Various further work includes factors causing glacier retreat and aerosols. User facilities are listed, including accelerators, the SLS light source, the SINQ neutron source, the UCN ultra-cold neutron

  9. RESEARCH HIGHLIGHTS IN IAS

    Directory of Open Access Journals (Sweden)

    Marko Kreft

    2017-03-01

    Full Text Available We are reviewing and commenting highlights of the research published in Image Analysis and Stereology journal (IAS, volume 35, where 16 original research papers on image analysis, computer vision, modelling, and other approaches were published. We have reported on the precision of curve length estimation in the plane. Further, a focus was on a robust estimation technique for 3D point cloud registration. Next contribution in computer vision was on the accuracy of stereo matching algorithm based on illumination control. An attempt was also made to automatically diagnose prenatal cleft lip with representative key points and identify the type of defect in three-dimensional ultrasonography. Similarly, a new report is presenting estimation of torsion of digital curves in 3D images and next, the nuchal translucency by ultrasound is being analyzed. Also in ophthalmology, image analysis may help physicians to establish a correct diagnosis, which is supported by a new approach to measure tortuosity of retinal vessel. Another report of medical significance analyzed correlation of the shape parameters for characterization of images of corneal endothelium cells. Shape analysis is also an important topic in material science, e.g. in analyzing fine aggregates in concrete. As in concrete, in fiber reinforced composites image analysis may aid in improved quality, where the direction of fibers have decisive impact on properties. Automatic defect detection using a computer vision system improves productivity quality in industrial production, hence we report of a new Haar wavelet-based approach.

  10. ESO Highlights in 2008

    Science.gov (United States)

    2009-01-01

    As is now the tradition, the European Southern Observatory looks back at the exciting moments of last year. 2008 was in several aspects an exceptionally good year. Over the year, ESO's telescopes provided data for more than 700 scientific publications in refereed journals, making ESO the most productive ground-based observatory in the world. ESO PR Highlights 2008 ESO PR Photo 01a/09 The image above is a clickable map. These are only some of the press releases issued by ESO in 2008. For a full listing, please go to ESO 2008 page. Austria signed the agreement to join the other 13 ESO member states (ESO 11/08 and 20/08), while the year marked the 10th anniversary of first light for ESO's "perfect science machine", the Very Large Telescope (ESO 16/08 and 17/08). The ALMA project, for which ESO is the European partner, had a major milestone in December, as the observatory was equipped with its first antenna (ESO 49/08). Also the Atacama Pathfinder Experiment (APEX) telescope impressed this year with some very impressive and publicly visible results. Highlights came in many fields: Astronomers for instance used the Very Large Telescope (VLT) to discover and image a probable giant planet long sought around the star Beta Pictoris (ESO 42/08). This is now the eighth extrasolar planet to have been imaged since the VLT imaged the first extrasolar planet in 2004 (three of eight were imaged with VLT). The VLT also enabled three students to confirm the nature of a unique planet (ESO 45/08). This extraordinary find, which turned up during their research project, is a planet about five times as massive as Jupiter. This is the first planet discovered orbiting a fast-rotating hot star. The world's foremost planet-hunting instrument, HARPS, located at ESO's La Silla observatory, scored a new first, finding a system of three super-Earths around a star (ESO 19/08). Based on the complete HARPS sample, astronomers now think that one Sun-like star out of three harbours short orbit, low

  11. Implications of sediment transport by subglacial water flow for interpreting contemporary glacial erosion rates

    Science.gov (United States)

    Beaud, Flavien; Flowers, Gwenn E.; Venditti, Jeremy G.

    2017-04-01

    of the channel by sediment storage leads to enhanced shear stresses and transport rates. As a result, assuming a constant sediment input and a seasonal water forcing sediment delivery to the proglacial environment undergoes two phases determined by a combination of meltwater discharge and channel development. In the stage of the melt season dominated by channel growth and increasing discharge, the sediment yield is virtually constant and matches the input. In contrast, during the stage dominated by channel closure and decreasing discharge the sediment yield exhibits daily fluctuations caused by temporary sediment storage in the channel. Our findings thus suggest that contemporary sediment yields may be controlled by the dynamics of subglacial water flow in the vicinity of the terminus. This provides a new perspective for the interpretation of proglacial sediment fluxes, fluxes which are central to refining glacial erosion laws utilized in landscape evolution models.

  12. Determination of the bedload transport rate in a small proglacial High Arctic stream using direct, semi-continuous measurement

    Science.gov (United States)

    Kociuba, Waldemar

    2017-06-01

    The article presents the results of a 34-day series of direct semi-continuous measurements of the bedload transport, performed during the melt season 2013 in the Scott River catchment (NW part of the Wedel-Jarlsberg Land, Spitsbergen). The daily variability of the bedload transport rates and its relation to the dissolved and suspended load were analysed in two cross-sections located in the lower course of a proglacial gravel-bed river. The bedload flux was measured by means of two 4-module sets of River Bedload Traps (RBT). In the research period, a total of 34 day-long samples of bedload and 34 water samples for the determination of the dissolved and suspended load were collected in each of the two cross-sections, 200 m apart. The measurements showed longitudinal and temporal variability of bedload flux and the remaining components (solutions, suspensions) corresponding with changes in water discharge. The mean daily bedload flux QB in consecutive measurement cross-sections XS amounted to 124 kg d- 1XS I and 59 kg d- 1XS II, respectively, and showed high variability and an evident relationship with temperature. The unequal bedload flux of the two measuring stations XS I and XS II suggests aggradation within the alluvial fan that separates the two reaches. The volume and rate of bedload flux were determined by the frequency of the occurrence of flood flows during which approximately from 59% XS I to 77% XS II of total bedload was discharged. The highest recorded daily values constituted 12% of total bedload flux. Through the cross-section below the alluvial fan, the river discharged approximately 6 million cubic meters (M m3) of water, 3 t of bedload Lb, 2238 t of suspended load Ls, and 613 t of dissolved load Ld. The relationships between the three components of the load suggest a 500-fold excess of suspended load, and a 100-fold excess of dissolved load in relation to bedload flux. High temporal and latitudinal variability of the bedload transport rate resulted

  13. The Role of Ice Blocks in the Creation of Distinctive Proglacial Landscapes During and Following the November 1996 Glacier-Outburst Flood \\(j\\H{o}kulhlaup\\), Skeidararsandur, Southern Iceland.

    Science.gov (United States)

    Fay, H.

    2001-12-01

    form kettle-scours produced by partial burial and scour during the flood and in situ ice block melt after the flood recedes. Rapid sediment deposition around ice blocks, followed by a lack of reworking, results in the formation of entirely aggradational ice block obstacle shadows and hummocky topography. On radial outwash fans where topography is unconfined, kettle holes and obstacle marks occur in distinct clusters. In areas of high j\\H{o}kulhlaup sediment flux, kettle holes form by the in situ melt of (1) progressively buried ice blocks and (2) small flow incorporated ice blocks. In locations subjected to a high sediment flux and high flow velocities, ice block melt-out till is superimposed onto obstacle marks and kettle holes. This study will provide a better understanding of j\\H{o}kulhlaup impact, which will, in turn, lead to improved j j\\H{o}kulhlaup prediction. Knowledge of associations between ice blocks and the bedforms and facies produced during and following a j\\H{o}kulhlaup will aid j\\H{o}kulhlaup identification and reconstruction in ancient proglacial areas including flood identification within the stratigraphic record.

  14. Sediment impacts on marine sponges.

    Science.gov (United States)

    Bell, James J; McGrath, Emily; Biggerstaff, Andrew; Bates, Tracey; Bennett, Holly; Marlow, Joseph; Shaffer, Megan

    2015-05-15

    Changes in sediment input to marine systems can influence benthic environments in many ways. Sponges are important components of benthic ecosystems world-wide and as sessile suspension feeders are likely to be impacted by changes in sediment levels. Despite this, little is known about how sponges respond to changes in settled and suspended sediment. Here we review the known impacts of sedimentation on sponges and their adaptive capabilities, whilst highlighting gaps in our understanding of sediment impacts on sponges. Although the literature clearly shows that sponges are influenced by sediment in a variety of ways, most studies confer that sponges are able to tolerate, and in some cases thrive, in sedimented environments. Critical gaps exist in our understanding of the physiological responses of sponges to sediment, adaptive mechanisms, tolerance limits, and the particularly the effect of sediment on early life history stages. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Substantial export of suspended sediment to the global oceans from glacial erosion in Greenland

    Science.gov (United States)

    Overeem, I.; Hudson, B. D.; Syvitski, J. P. M.; Mikkelsen, A. B.; Hasholt, B.; van den Broeke, M. R.; Noël, B. P. Y.; Morlighem, M.

    2017-11-01

    Limited measurements along Greenland's remote coastline hamper quantification of the sediment and associated nutrients draining the Greenland ice sheet, despite the potential influence of river-transported suspended sediment on phytoplankton blooms and carbon sequestration. Here we calibrate satellite imagery to estimate suspended sediment concentration for 160 proglacial rivers across Greenland. Combining these suspended sediment reconstructions with numerical calculations of meltwater runoff, we quantify the amount and spatial pattern of sediment export from the ice sheet. We find that, although runoff from Greenland represents only 1.1% of the Earth's freshwater flux, the Greenland ice sheet produces approximately 8% of the modern fluvial export of suspended sediment to the global ocean. Sediment loads are highly variable between rivers, consistent with observed differences in ice dynamics and thus with control by glacial erosion. Rivers that originate from deeply incised, fast-moving glacial tongues form distinct sediment-export hotspots: just 15% of Greenland's rivers transport 80% of the total sediment load of the ice sheet. We conclude that future acceleration of melt and ice sheet flow may increase sediment delivery from Greenland to its fjords and the nearby ocean.

  16. Dinâmica Glacial e Características Sedimentares Resultantes na Zona Proglacial da Geleira Ecology-Baía do Almirantado, Ilha Rei George Antártica.

    Directory of Open Access Journals (Sweden)

    Kátia Kellem Rosa

    2006-12-01

    Full Text Available A geleira Ecology, localizada na ilha Rei George, ilhas Shetlands do Sul, está sofrendo um processo de rápida retração ao longo das últimas décadas, sendo que no período de 1956 a 1992/95 a geleira retrocedeu 0,37 Km2. Isto gerou um ambiente de deglaciação, com a exposição de várias geoformas na zona proglacial. Este trabalho objetiva estudar o ambiente de deglaciação da zona proglacial da geleira Ecology e seus respectivos depósitos na zona proglacial, além de inferir o regime termo-basal desta geleira. O produto resultante deste trabalho é a criação de um modelo geomorfológico para a zona proglacial da geleira, o qual pode ser usado para comparar com zonas proglaciais de outras geleiras.

  17. Highlighting Impact and the Impact of Highlighting: PRB Editors' Suggestions

    OpenAIRE

    Antonoyiannakis, Manolis

    2016-01-01

    Associate Editor Manolis Antonoyiannakis discusses the highlighting, as Editors' Suggestions, of a small percentage of the papers published each week. We highlight papers primarily for their importance and impact in their respective fields, or because we find them particularly interesting or elegant. It turns out that the additional layer of scrutiny involved in the selection of papers as Editors' Suggestions is associated with a significantly elevated and sustained citation impact.

  18. Temperature signal in suspended sediment export from an Alpine catchment

    Directory of Open Access Journals (Sweden)

    A. Costa

    2018-01-01

    Full Text Available Suspended sediment export from large Alpine catchments ( >  1000 km2 over decadal timescales is sensitive to a number of factors, including long-term variations in climate, the activation–deactivation of different sediment sources (proglacial areas, hillslopes, etc., transport through the fluvial system, and potential anthropogenic impacts on the sediment flux (e.g. through impoundments and flow regulation. Here, we report on a marked increase in suspended sediment concentrations observed near the outlet of the upper Rhône River Basin in the mid-1980s. This increase coincides with a statistically significant step-like increase in basin-wide mean air temperature. We explore the possible explanations of the suspended sediment rise in terms of changes in water discharge (transport capacity, and the activation of different potential sources of fine sediment (sediment supply in the catchment by hydroclimatic forcing. Time series of precipitation and temperature-driven snowmelt, snow cover, and ice melt simulated with a spatially distributed degree-day model, together with erosive rainfall on snow-free surfaces, are tested to explore possible reasons for the rise in suspended sediment concentration. We show that the abrupt change in air temperature reduced snow cover and the contribution of snowmelt, and enhanced ice melt. The results of statistical tests show that the onset of increased ice melt was likely to play a dominant role in the suspended sediment concentration rise in the mid-1980s. Temperature-driven enhanced melting of glaciers, which cover about 10 % of the catchment surface, can increase suspended sediment yields through an increased contribution of sediment-rich glacial meltwater, increased sediment availability due to glacier recession, and increased runoff from sediment-rich proglacial areas. The reduced extent and duration of snow cover in the catchment are also potential contributors to the rise in suspended sediment

  19. Research highlights: impacts of microplastics on plankton.

    Science.gov (United States)

    Lin, Vivian S

    2016-02-01

    Each year, millions of metric tons of the plastic produced for food packaging, personal care products, fishing gear, and other human activities end up in lakes, rivers, and the ocean. The breakdown of these primary plastics in the environment results in microplastics, small fragments of plastic typically less than 1-5 mm in size. These synthetic particles have been detected in all of the world's oceans and also in many freshwater systems, accumulating in sediment, on shorelines, suspended in surface waters, and being ingested by plankton, fish, birds, and marine mammals. While the occurrence of plastics in surface waters has been surveyed in a number of studies, the impacts of microplastics on marine organisms are still being elucidated. This highlight features three recent publications that explore the interactions of microplastics with planktonic organisms to clarify the effects of these pollutants on some of the ocean's smallest and most important inhabitants.

  20. Depositional environment of a fan delta in a Vistulian proglacial lake (Skaliska Basin, north-eastern Poland

    Directory of Open Access Journals (Sweden)

    Woronko Barbara

    2013-06-01

    Full Text Available The study reconstructed the environment of a fan delta filling the vast end depression of the Skaliska Basin, and its overlying aeolian deposits. The formation of the large fan delta is associated with the presence of an ice-dammed lake functioning during the retreat of the Vistulian Glaciation (MIS 2. The examined material was collected from five boreholes. Sediments were analysed for their granulometric composition and subjected to analyses of frosting and rounding of quartz grains. Grain size analysis showed that the fan delta deposits are built of sand sediments of very low lateral and vertical variability. The fan delta was supplied with fluvioglacial sediments. Accumulation of sediments occurred in shallow water with a very low-gradient slope. The exposed fan delta became a site conducive to aeolian processes after the lake waters fell and the Skaliska Basin depression dried. Dune deposits overlying the fan were affected by short-distance transport so they did not acquire features typical for aeolian deposits.

  1. High-resolution measurements of morphodynamics in rapidly changing PROglacial Systems of the Alps - results from the PROSA project

    Science.gov (United States)

    Hilger, Ludwig; Dusik, Jana-Marie; Heckmann, Tobias; Haas, Florian; Näher, Martin; Philipp, Rumohr; Philipp, Glira; Lucas, Vehling; Michael, Becht

    2016-04-01

    In June 2012, the PROSA-project was initiated with the goal to construct a sediment budget of the Upper Kaunertal Valley, Ötztal Alps, Austria. A unique feature of the project being the dedicated usage of study-area wide multi-volume LiDAR survey data of relatively high density on a meso-scale catchment resulting in a data base of over 4 billion LiDAR measurement points. A high effort was undertaken to produce classified point data as a methodological backbone of the project. Both ALS and georeferenced TLS data as well as other remote sensing and mapping products were used in addition to extensive fieldwork as basis for a regionalization of monitoring-site based measurements to arrive at basin-wide sediment production rates and identification of sediment pathways. Results can now be presented for: Rock fall (plot-based measurement and subsequent model-based regionalization), debris flows (study area-wide direct measurement from LiDAR and analysis of historical orthophotos), rock glaciers (feature-tracking and direct differencing), hillslope channels (plot-based measurements and model-based regionalization) and avalanches (sample site measurement, mapping and extrapolation). Sediment budgets were subsequently constructed for different representative subsystems within the 62.5 km2 catchment. Although also glacier and main channel transport was looked into by the PROSA-project, the presentation will focus on the processes mentioned above.

  2. New age constraints for the Saalian glaciation in northern central Europe: Implications for the extent of ice sheets and related proglacial lake systems

    Science.gov (United States)

    Lang, Jörg; Lauer, Tobias; Winsemann, Jutta

    2018-01-01

    A comprehensive palaeogeographic reconstruction of ice sheets and related proglacial lake systems for the older Saalian glaciation in northern central Europe is presented, which is based on the integration of palaeo-ice flow data, till provenance, facies analysis, geomorphology and new luminescence ages of ice-marginal deposits. Three major ice advances with different ice-advance directions and source areas are indicated by palaeo-ice flow directions and till provenance. The first ice advance was characterised by a southwards directed ice flow and a dominance of clasts derived from southern Sweden. The second ice advance was initially characterised by an ice flow towards the southwest. Clasts are mainly derived from southern and central Sweden. The latest stage in the study area (third ice advance) was characterised by ice streaming (Hondsrug ice stream) in the west and a re-advance in the east. Clasts of this stage are mainly derived from eastern Fennoscandia. Numerical ages for the first ice advance are sparse, but may indicate a correlation with MIS 8 or early MIS 6. New pIRIR290 luminescence ages of ice-marginal deposits attributed to the second ice advance range from 175 ± 10 to 156 ± 24 ka and correlate with MIS 6. The ice sheets repeatedly blocked the main river-drainage pathways and led to the formation of extensive ice-dammed lakes. The formation of proglacial lakes was mainly controlled by ice-damming of river valleys and major bedrock spillways; therefore the lake levels and extends were very similar throughout the repeated ice advances. During deglaciation the lakes commonly increased in size and eventually drained successively towards the west and northwest into the Lower Rhine Embayment and the North Sea. Catastrophic lake-drainage events occurred when large overspill channels were suddenly opened. Ice-streaming at the end of the older Saalian glaciation was probably triggered by major lake-drainage events.

  3. Coastal sedimentation

    Science.gov (United States)

    Schubel, J. R.

    1980-01-01

    Several important coastal sedimentation problems are identified. Application of existing or anticipated remote sensing techniques to examine these problems is considered. Specifically, coastal fine particle sediment systems, floods and hy hurricanes and sedimentation f of coastal systems, routes and rates of sediment transport on continental shelves, and dredging and dredged material disposal are discussed.

  4. The impact of climate change on sediment delivery from the Jostedalsbreen ice cap, Southern Norway

    Science.gov (United States)

    Bogen, Jim; Xu, Mengzhen; Melvold, Kjetil

    2015-04-01

    one small overdeepening has been observed beneath Nigardsbreen. Hence, sediment transport of this glacier will not be affected notecably. However, calving will become an important factor contributing to ablation for many other glaciers, for example, Tunsbergdalsbreen, Supphellebreen, Bøyabreen, etc. During calving, all the sediment in the glacier sole will melt out. However, a large amount of the sediment will be trapped in the proglacial lakes and not be delivered to the rivers downstream of the lakes. Keywords: climate change, glacial sediment transport, proglacial lakes, glacier hydrology

  5. Southeast Alaska forests: inventory highlights.

    Science.gov (United States)

    Sally Campbell; Willem W.S. van Hees; Bert. Mead

    2004-01-01

    This publication presents highlights of a recent southeast Alaska inventory and analysis conducted by the Pacific Northwest Research Station Forest Inventory and Analysis Program (USDA Forest Service). Southeast Alaska has about 22.9 million acres, of which two-thirds are vegetated. Almost 11 million acres are forest land and about 4 million acres have nonforest...

  6. Energy Policy. Highlights. 2013 Edition

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-07-01

    Energy Policy Highlights showcases recent developments in energy policies among all 28 IEA member countries. Each contribution underscores the changing nature of both global and domestic energy challenges, as well as the commonality of energy concerns among member countries. The policies highlighted in this publication identify an urgent need to reduce greenhouse gas (GHG) emissions as a clear policy objective. Electricity, enhancing energy efficiency and increasing the share of renewables in the energy mix in a cost effective manner are likewise areas of common focus. On the end-user side, increasing public awareness of domestic energy policies through improved transparency and engagement is an important facet of policy support among IEA member countries. The successful implementation of policies and other initiatives benefitted from efforts to inform the public.

  7. Highlights of Spanish Astrophysics VII

    Science.gov (United States)

    Guirado, J. C.; Lara, L. M.; Quilis, V.; Gorgas, J.

    2013-05-01

    "Highlights of Astronomy and Astrophysics VII" contains the Proceedings of the biannual meeting of the Spanish Astronomical Society held in Valencia from July 9 to 13, 2012. Over 300 astronomer, both national and international researchers, attended to the conference covering a wide variety of astrophysical topics: Galaxies and Cosmology, The Milky Way and Its Components, Planetary Sciences, Solar Physics, Instrumentation and Computation, and Teaching and Outreach of Astronomy.

  8. LHC Results Highlights (CLASHEP 2013)

    CERN Document Server

    Gonzalez, O.

    2015-05-22

    The good performance of the LHC provided enough data at 7 TeV and 8 TeV to allow the experiments to perform very competitive measurements and to expand the knowledge about the fundamental interaction far beyond that from previous colliders. This report summarizes the highlights of the results obtained with these data samples by the four large experiments, covering all the topics of the physics program and focusing on those exploiting the possibilities of the LHC.

  9. Optical highlighter molecules in neurobiology.

    Science.gov (United States)

    Datta, Sandeep Robert; Patterson, George H

    2012-02-01

    The development of advanced optical methods has played a key role in propelling progress in neurobiology. Genetically-encoded fluorescent molecules found in nature have enabled labeling of individual neurons to study their physiology and anatomy. Here we discuss the recent use of both native and synthetic optical highlighter proteins to address key problems in neurobiology, including questions relevant to synaptic function, neuroanatomy, and the organization of neural circuits. Copyright © 2011 Elsevier Ltd. All rights reserved.

  10. ESO PR Highlights in 2003

    Science.gov (United States)

    2004-01-01

    Among the many astronomical highlights of 2003, the Transit of Mercury certainly attracted great attention as shown by the record number of hits the ESO web page received on that day. But this was a mere rehearsal of an even bigger event we will enjoy in 2004: the Venus Transit. ESO, in partnership with several institutions, is organising a major educational event in connection with it. During 2003, the ESO Educational Office was also involved in various other programmes. They included the web-based "Catch a Star!" and the "Physics and Life" projects, organised with EC sponsorship in connection with the 2003 European Science and Technology Week. The ALMA project, an European-North American collaboration to build an array of 64 12-m submillimetre antennas, moved forward with the signature of the agreement between ESO and the NSF and with the Ground-breaking at Chajnantor. Conceptual studies of a 100-m optical/infrared telescope (OWL) also proceeded well. Several new instruments were installed at ESO telescopes, e.g. HARPS . And the VLT Interferometer (VLTI) received a powerful Adaptive Optics System and made the first detection through infrared interferometry of an extragalactic object. A rapidly increasing number of new scientific results were obtained on the basis of data from ESO telescopes, some of which were highlighted in ESO Press Releases. A number of beautiful images were published. Many of these developments are described in ESO's Press Releases, most with Press Photos, cf. the 2003 PR Index. Some of last year's ESO PR highlights may be accessed directly via the clickable image above.

  11. Highlights of DAMA/LIBRA

    OpenAIRE

    Bernabei R.; Belli P.; d’Angelo A.; d’Angelo S.; Di Marco A.; Montecchia F.; Incicchitti A.; Cappella F.; Caracciolo V.; Cerulli R.; Dai C.J.; He H.L.; Kuang H.H.; Ma X.H.; Sheng X.D.

    2016-01-01

    The DAMA project develops and uses new/improved low background scintillation detectors to investigate the Dark Matter (DM) particle component(s) in the galactic halo and rare processes deep underground at the Gran Sasso National Laboratory (LNGS) of the I.N.F.N.. Here some highlights of DAMA/LIBRA (Large sodium Iodide Bulk for Rare processes) as a unique apparatus in direct DM investigation for its full sensitive mass, target material, intrinsic radio-purity, methodological approach and all t...

  12. PHYSICS FOR HEALTH: CONFERENCE HIGHLIGHTS

    CERN Multimedia

    2016-01-01

    Highlights of ICTR-PHE 2016 - International Conference on Translational Research in Radio-Oncology and Physics for Health -, co organized by CERN, aims at developing new strategies to better diagnose and treat cancer, by uniting biology and physics with clinics. Through the various sessions and symposia, the scientific programme offers the delegates the opportunity to discuss, in a friendly atmosphere, the latest progress in physics breakthroughs for health applications. The third edition of this conference took place at CICG (Centre International de Conférence Genève) from 15 to 19 Feb 2016.

  13. Temporal dynamics of suspended sediment transport in a glacierized Andean basin

    Science.gov (United States)

    Mao, Luca; Carrillo, Ricardo

    2017-06-01

    Suspended sediment transport can affect water quality and aquatic ecosystems, and its quantification is of the highest importance for river and watershed management. Suspended sediment concentration (SSC) and discharge were measured at two locations in the Estero Morales, a Chilean Andean stream draining a small basin (27 km2) hosting glacierized areas of about 1.8 km2. Approximately half of the suspended sediment yield (470 t year- 1 km- 2) was transported during the snowmelt period and half during glacier melting. The hysteresis patterns between discharge and SSC were calculated for each daily hydrograph and were analysed to shed light on the location and activity of different sediment sources at the basin scale. During snowmelt, an unlimited supply of fine sediments is provided in the lower and middle part of the basin and hysteresis patterns tend to be clockwise as the peaks in SSC precede the peak of discharge in daily hydrographs. Instead, during glacier melting the source of fine sediments is the proglacial area, producing counterclockwise hysteresis. It is suggested that the analysis of hysteretic patterns over time provides a simple concept for interpreting variability of location and activity of sediment sources at the basin scale.

  14. Highlighting inconsistencies regarding metal biosorption.

    Science.gov (United States)

    Robalds, Artis; Naja, Ghinwa Melodie; Klavins, Maris

    2016-03-05

    Thousands of articles have been devoted to examine different types of biosorbents and their use in cleaning polluted waters. An important objective of some studies has been the identification of the biosorption mechanisms. This type of investigation is not always performed, as it can only be done if scientists are aware of all mechanisms that, at least theoretically, control the removal of the target substances. Mistakes are often made, even in highly cited review articles, where biosorption mechanisms are named and/or grouped. The aim of this article is to highlight errors and inaccuracies as well as to discuss different classification systems of the biosorption mechanisms. This article serves as a guide, as well as a platform for discussion among researchers involved in the investigation of biosorbents, in an effort to avoid reproducing errors in subsequent articles. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Highlights in pathogenesis of vitiligo

    Science.gov (United States)

    Mohammed, Ghada F; Gomaa, Amal HA; Al-Dhubaibi, Mohammed Saleh

    2015-01-01

    Vitiligo is a common pigmentary disorder. Many studies across decades and all over the world have attempted to illustrate the pathogenesis behind it; however, the pathogenesis of vitiligo remains elusive. This review article, we present the findings behind the most and updated theories behind this psychologically debilitating and disfiguring disease. The discussion begun with the role of genetic predisposition followed by neural theory first proposed in the 1950s. We highlight the autoimmune hypothesis, followed by the reactive oxygen species model, zinc-α2-glycoprotein deficiency hypothesis, viral theory, intrinsic theory and biochemical, molecular and cellular alterations accounting for loss of functioning melanocytes in vitiligo. Many theories were elaborated to clarify vitiligo pathogenesis. It is a multifactorial disease involving the interplay of several factors. Future research is needed to clarify the interaction of these factors for better understanding of vitiligo pathogenesis and subsequent successful treatment. PMID:25789295

  16. Evolution of ice-dammed proglacial lakes in Última Esperanza, Chile: implications from the late-glacial R1 eruption of Reclús volcano, Andean Austral Volcanic Zone Evolución de lagos proglaciales embalsados por hielo en Última Esperanza, Chile: Implicancias de la explosión volcánica tardiglacial R1 del volcán Reclús, Zona Volcánica Austral Andina

    Directory of Open Access Journals (Sweden)

    Charles R Stern

    2011-01-01

    Full Text Available Newly described outerops, excavations and sediment cores from the region of Última Esperanza, Magallanes, contain tephra derived from the large late-glacial explosive Rl eruption of the Reclús volcano in the Andean Austral Volcanic Zone. New radiocarbon dates associated to these deposits refine previous estimates of the age, to 14.9 cal kyrs BP (12,670±240 14C yrs BP, and volume, to >5 km³, of this tephra. The geographic and stratigraphic distribution of Rl also place constraints on the evolution of the ice-dammed proglacial lake that existed east of the cordillera in this area between the termination of the Last Glacial Maximum (LGM and the Holocene. This proglacial lake generated wave-cut terraces, and also caves, such as the Cueva de Milodón, along the highest prominent terrace. The current elevation of these terraces depends on the total amount of post-glacial isostatic rebound, which is unknown. Due to differential rebound, the highest prominent lake terraces decrease in height from west-to-east, from -170 m a.s.l. on Península Antonio Varas west of Seno Ultima Esperanza, to-150 m a.s.l. aroundLago Sofía, anddownto-125 m a.s.l. along their easternmost margin. The presence of thick deposits of Rl tephra in some of the caves around Lago Sofía implies that the proglacial lake had already dropped below its highest level prior to the time of this eruption, and, in fact, even earlier, prior to 16.1 cal kyrs BP (13,560±180 14C yrs BP, when land mammals first oceupied these caves. The depositional environment of Rl in a core from Dumestre bog suggests that the lake level was in fact 70 m a.s.l. until 12.8 cal kyrs BP (10,695±40 14C yrs BP. However, a 14.2 cal kyrs BP (12,125±85 14C yrs BF Mylodon pelvis from a nearby site, located at only -7 m a.s.l., suggests that the lake could have emptied, for at least a brief period, to this low level at this time. This latter datum, combined with the lack of any prominent terraces between the

  17. Highlights in pathogenic fungal biofilms.

    Science.gov (United States)

    Sardi, Janaina De Cássia Orlandi; Pitangui, Nayla De Souza; Rodríguez-Arellanes, Gabriela; Taylor, Maria Lucia; Fusco-Almeida, Ana Maria; Mendes-Giannini, Maria José Soares

    2014-01-01

    A wide variety of fungi have demonstrated the ability to colonize surfaces and form biofilms. Most studies on fungal biofilms have focused on Candida albicans and more recently, several authors have reported the involvement of other genera of yeasts and Candida species, as well as of filamentous fungi in the formation of biofilms, including: Cryptococcus neoformans, Cryptococcus gattii, Rhodotorula species, Aspergillus fumigatus, Malassezia pachydermatis, Histoplasma capsulatum, Paracoccidioides brasiliensis, Pneumocystis species, Coccidioides immitis, Fusarium species, Saccharomyces cerevisiae, Trichosporon asahii, Mucorales and Blastoschizomyces. There is a current interest in describing the particular characteristics of the biofilm formation by of these fungi. A major concern is the control of biofilms, requiring knowledge of the biofilm mechanisms. However, our knowledge of these microbial communities is limited, due to the complexity of these systems and metabolic interactions that remain unknown. This mini-review aims to highlight recently discovered fungal biofilms and to compare them with the current knowledge on biofilms. This manuscript is part of the series of works presented at the "V International Workshop: Molecular genetic approaches to the study of human pathogenic fungi" (Oaxaca, Mexico, 2012). Copyright © 2013 Revista Iberoamericana de Micología. Published by Elsevier Espana. All rights reserved.

  18. Highlights from the CMS Experiment

    CERN Document Server

    Alcaraz Maestre, Juan

    2017-01-01

    We discuss the status and some recent results of the CMS experiment at the LHC. The performance of the detector is assessed using a luminosity of $\\approx 5~\\mathrm{fb}^{-1}$ recorded in the first part of the 2017 data-taking period. Run~2 physics studies use data collected at a center-of-mass energy of $\\sqrt{s}=13~\\mathrm{TeV}$, corresponding to an integrated luminosity of $36~\\mathrm{fb}^{-1}$. Highlights from studies in the Higgs sector are the first observation of its decay into tau leptons by a single experiment, the most precise measurement of its mass, $\\mathrm{m_H} = 125.26 \\pm 0.21~\\mathrm{GeV}$ and a first search for the $\\mathrm{H}\\to\\mathrm{b\\overline{b}}$ decay in a phase space region that is sensitive to the gluon-fusion production mechanism. In the electroweak sector, CMS provides the currently most precise measurement of the effective weak mixing angle at the LHC: $\\sin\\theta^{\\rm lept}_{\\rm eff} = 0.23101\\pm 0.00052$, using an integrated luminosity of $\\approx 20~\\mathrm{fb}^{-1}$ at $\\sqr...

  19. Highlights of DAMA/LIBRA

    Directory of Open Access Journals (Sweden)

    Bernabei R.

    2016-01-01

    Full Text Available The DAMA project develops and uses new/improved low background scintillation detectors to investigate the Dark Matter (DM particle component(s in the galactic halo and rare processes deep underground at the Gran Sasso National Laboratory (LNGS of the I.N.F.N.. Here some highlights of DAMA/LIBRA (Large sodium Iodide Bulk for Rare processes as a unique apparatus in direct DM investigation for its full sensitive mass, target material, intrinsic radio-purity, methodological approach and all the controls performed on the experimental parameters are outlined. The DAMA/LIBRA–phase1 and the former DAMA/NaI data (cumulative exposure 1.33 ton × yr, corresponding to 14 annual cycles have reached a model-independent evidence at 9.3 σ C.L. for the presence of DM particles in the galactic halo exploiting the DM annual modulation signature with highly radio-pure NaI(Tl target. Some of the perspectives of the presently running DAMA/LIBRA–phase2 are summarised and the powerful tools offered by a model independent strategy of DM investigation are pointed out.

  20. ESO PR Highlights in 2004

    Science.gov (United States)

    2005-01-01

    new interesting scientific results on the basis of data from ESO telescopes, including several results from the unmatched interferometer mode of the VLT, the VLTI, some of which were highlighted in ESO Press Releases. Certainly worth noting is the possible first ever bona-fide image of an exoplanet and the discovery of the lightest known exoplanet . At the beginning of the year, Paranal welcomed the first Auxiliary Telescope, while on the instrument side as well, 2004 was a good year: we saw the arrival of SINFONI on the VLT, of AMBER on the VLTI, and the installation at the NACO Adaptive Optics instrument of the " Simultaneous Differential Imager (SDI)" to detect exoplanets. And the first prototype of the Astrophysical Virtual Observatory was able to provide unprecedented results on the existence of Type-2 quasars by discovering an entire population of obscured, powerful supermassive black holes. Many of these developments are described in ESO's Press Releases, most with Press Photos, cf. the 2004 PR Index. Some of last year's ESO PR highlights may be accessed directly via the clickable image above.

  1. Sediment Transport

    DEFF Research Database (Denmark)

    Liu, Zhou

    Flow and sediment transport are important in relation to several engineering topics, e.g. erosion around structures, backfilling of dredged channels and nearshore morphological change. The purpose of the present book is to describe both the basic hydrodynamics and the basic sediment transport...... mechanics. Chapter 1 deals with fundamentals in fluid mechanics with emphasis on bed shear stress by currents, while chapter 3 discusses wave boundary layer theory. They are both written with a view to sediment transport. Sediment transport in rivers, cross-shore and longshore are dealt with in chapters 2...

  2. Cassini's Grand Finale Science Highlights

    Science.gov (United States)

    Spilker, Linda

    2017-10-01

    After 13 years in orbit, the Cassini-Huygens Mission to Saturn ended in a science-rich blaze of glory. Cassini returned its final bits of unique science data on September 15, 2017, as it plunged into Saturn's atmosphere satisfying planetary protection requirements. Cassini's Grand Finale covered a period of roughly five months and ended with the first time exploration of the region between the rings and planet.The final close flyby of Titan in late April 2017 propelled Cassini across Saturn’s main rings and into its Grand Finale orbits; 22 orbits that repeatedly dove between Saturn’s innermost rings and upper atmosphere making Cassini the first spacecraft to explore this region. The last orbit turned the spacecraft into the first Saturn upper atmospheric probe.The Grand Finale orbits provided highest resolution observations of both the rings and Saturn, and in-situ sampling of the ring particle composition, Saturn's atmosphere, plasma, and innermost radiation belts. The gravitational field was measured to unprecedented accuracy, providing information on the interior structure of the planet, winds in the deeper atmosphere, and mass of the rings. The magnetic field provided insight into the physical nature of the magnetic dynamo and structure of the internal magnetic field. The ion and neutral mass spectrometer sampled the upper atmosphere for molecules that escape the atmosphere in addition to molecules originating from the rings. The cosmic dust analyzer directly sampled the composition from different parts of the main rings for the first time. Fields and particles instruments directly measured the plasma environment between the rings and planet.Science highlights and new mysteries gleaned to date from the Grand Finale orbits will be discussed.The research described in this paper was carried out in part at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. Copyright 2017

  3. ESO PR Highlights in 2005

    Science.gov (United States)

    2006-01-01

    2005 was the year of Physics. It was thus also in part the year of astronomy and this is clearly illustrated by the numerous breakthroughs that were achieved, in particular using ESO's telescopes. One of the highlights was without any doubt the confirmation of the first image of an exoplanet , around the star 2M1207 (see ESO PR 12/05). ESO's telescopes also found a Neptune-mass exoplanet around a small star ( PR 30/05) - a discovery that proves crucial in the census of other planetary systems, and imaged a tiny companion in the close vicinity of the star GQ Lupi, a very young object still surrounded by a disc, with an age between 100,000 and 2 million years ( PR 09/05). Moreover, using a new high-contrast adaptive optics camera on the VLT, the NACO Simultaneous Differential Imager, or NACO SDI, astronomers were able for the first time to image a companion 120 times fainter than its star , very near the star AB Doradus A. This companion appears to be almost twice as heavy as theory predicts it to be ( PR 02/05). ESO's telescopes proved very useful in helping to solve a 30-year old puzzle . Astronomers have for the first time observed the visible light from a short gamma-ray burst (GRB). Using the 1.5m Danish telescope at La Silla (Chile), they showed that these short, intense bursts of gamma-ray emission most likely originate from the violent collision of two merging neutron stars ( PR 26/05). Additional evidence came from witnessing another event with the VLT ( PR 32/05). Also in this field, astronomers found the farthest known gamma-ray burst with ESO's VLT, observing an object with a redshift 6.3, i.e. that is seen when the Universe was less than 900 million years old ( PR 22/05). On July 4, NASA's Deep Impact spacecraft plunged onto Comet 9P/Tempel 1 with the aim to create a crater and expose pristine material from beneath the surface. For two days before and six days after, all major ESO telescopes have been observing the comet, in a coordinated fashion and in

  4. Release of PCBs from Silvretta glacier (Switzerland) investigated in lake sediments and meltwater.

    Science.gov (United States)

    Pavlova, P A; Zennegg, M; Anselmetti, F S; Schmid, P; Bogdal, C; Steinlin, C; Jäggi, M; Schwikowski, M

    2016-06-01

    This study is part of our investigations about the release of persistent organic pollutants from melting Alpine glaciers and the relevance of the glaciers as secondary sources of legacy pollutants. Here, we studied the melt-related release of polychlorinated biphenyls (PCBs) in proglacial lakes and glacier streams of the catchment of the Silvretta glacier, located in the Swiss Alps. To explore a spatial and temporal distribution of chemicals in glacier melt, we combined two approaches: (1) analysing a sediment record as an archive of past remobilization and (2) passive water sampling to capture the current release of PCBs during melt period. In addition, we determined PCBs in a non-glacier-fed stream as a reference for the background pollutant level in the area. The PCBs in the sediment core from the Silvretta lake generally complied with trends of PCB emissions into the environment. Elevated concentrations during the most recent ten years, comparable in level with times of the highest atmospheric input, were attributed to accelerated melting of the glacier. This interpretation is supported by the detected PCB fractionation pattern towards heavier, less volatile congeners, and by increased activity concentrations of the radioactive tracer (137)Cs in this part of the sediment core. In contrast, PCB concentrations were not elevated in the stream water, since no significant difference between pollutant concentrations in the glacier-fed and the non-glacier-fed streams was detected. In stream water, no current decrease of the PCBs with distance from the glacier was observed. Thus, according to our data, an influence of PCBs release due to accelerated glacier melt was only detected in the proglacial lake, but not in the other compartments of the Silvretta catchment.

  5. Atmospheric Research 2014 Technical Highlights

    Science.gov (United States)

    Platnick, Steven

    2015-01-01

    Earth Sciences Division in atmospheric science research. Figure 1.1 shows the 20-year record of peer-reviewed publications and proposals among the various Laboratories. This data shows that the scientific work being conducted in the Laboratories is competitive with the work being done elsewhere in universities and other government agencies. The office of Deputy Director for Atmospheric Research will strive to maintain this record by rigorously monitoring and promoting quality while emphasizing coordination and integration among atmospheric disciplines. Also, an appropriate balance will be maintained between the scientists' responsibility for large collaborative projects and missions and their need to carry out active science research as a principal investigator. This balance allows members of the Laboratories to improve their scientific credentials, and develop leadership potentials. Interdisciplinary research is carried out in collaboration with other laboratories and research groups within the Earth Sciences Division, across the Sciences and Exploration Directorate, and with partners in universities and other government agencies. Members of the Laboratories interact with the general public to support a wide range of interests in the atmospheric sciences. Among other activities, the Laboratories raise the public's awareness of atmospheric science by presenting public lectures and demonstrations, by making scientific data available to wide audiences, by teaching, and by mentoring students and teachers. The Atmosphere Laboratories make substantial efforts to attract and recruit new scientists to the various areas of atmospheric research. We strongly encourage the establishment of partnerships with Federal and state agencies that have operational responsibilities to promote the societal application of our science products. This report describes our role in NASA's mission, provides highlights of our research scope and activities, and summarizes our scientists' major

  6. The analysis of remote sensing data to delineate landsystem tracts in proglacial valleys in the Río Santa Basin, Cordillera Blanca, Perú

    Science.gov (United States)

    Narro Perez, R. A.; Eyles, C.

    2016-12-01

    The Río Santa Basin is an important glacially-influenced basin of social, economic and cultural importance to the country of Perú. It produces a large portion of Peru's hydroelectricity, is an important agricultural area, and hosts two major mining complexes. The Río Santa receives its water from precipitation, glacial runoff from over 450 glaciers draining the Cordillera Blanca, and groundwater discharge. Despite being the largest tropical glacier ice field in the world, the area of glacial coverage in the Cordillera Blanca has decreased from 825 km2 in 1930 to 528 km2 in 2003. It is estimated that glacial runoff contributes 10-20% of the Río Santa's annual flow but during the dry season it can contribute up to 66% of water flow with groundwater supplying the remainder. The contribution of glacial meltwater makes the Río Santa less susceptible to discharge variability caused by inter-annual variation in precipitation. Due to decreased meltwater contributions, the urban centers and rural communities in the basin are expected to face severe water scarcity in the future, especially during the dry season. This poster will show the results of a remote sensing survey, using Google Earth and LiDAR data, to delineate landsystem tracts and components in several proglacial valleys in the Cordillera Blanca. The results of this survey allow detailed documentation of the geomorphological evolution of the landscape which will in turn allow a better understanding of the glacial history and subsurface geology of the area. These findings will better inform current hydrogeological models used to determine the sustainability of water resources in the Río Santa basin. Understanding the landsystem architecture, sedimentology and subsurface stratigraphy of the basin will also allow these models to more accurately predict the impact that future climate change will have on water resources and the people of the Río Santa basin.

  7. Towards a sediment budget estimation of the Gepatschferner glacier (Tyrol, Austria) - Approaches and first results

    Science.gov (United States)

    Faust, Matthias; Baewert, Henning; Morche, David

    2015-04-01

    Sediment production, storage and transport in glacial systems are spatially and temporally variable. Due to the ongoing global warming an accelerated glacial retreat is expected, leading to an exposure of unconsolidated sediments. Additionally, a higher sediment production from destabilised rock walls caused by permafrost degradation and glacial debuttressing is expected. At least those paraglacial processes become more important in alpine catchments in the near future. But, there is still a knowledge gap on the quantification of sediment transporting processes in those regions. The research questions we are focussing on are part of the PROSA project ("High-resolution measurements of morphodynamics in rapidly changing Proglacial Systems of the Alps") and are investigated at the Gepatschferner glacier. The Gepatschferner is located in the Eastern European Alps at the south end of the Kaunertal valley. It is the second largest glacier in Austria (15.7 km², 2012). The Gepatschferner is drained by the Fagge River. In this presentation we will focus on two main components of the sediment budget of the Gepatschferner: the input to and the output from the glacier system. The sediment input from the surrounding rockwalls to the glacier is observed by comparing multi-temporal airborne LiDAR DEMs (2006, July 2012, September 2012) to determine sediment delivery by rockfall. In 2012 a gauging station was installed at the Fagge River in front of the glacier outlet in oreder to determine the glacio-fluvial output of sediment from the glacier system. During the ablation periods from 2012 to 2014 the water level was recorded. At different stages the discharge was measured and a reliable stage-discharge relation could be established. That relation was used in combination with the recorded stage for the computation of the hydrograph in each season. Additionally, the solid sediment output was estimated using the discharge data as well as suspended sediment concentration from several

  8. ESO PR Highlights in 2007

    Science.gov (United States)

    2008-01-01

    Another great year went by for ESO, the European Organisation for Astronomical Research in the Southern Hemisphere. From 1 January 2007, with the official joining of the Czech Republic, ESO has 13 member states, and since September, ESO has a new Director General, Tim de Zeeuw (ESO 03/07 and 38/07). Many scientific discoveries were made possible with ESO's telescopes. Arguably, the most important is the discovery of the first Earth-like planet in the habitable zone of a low-mass red dwarf (ESO 22/07). If there is water on this planet, then it should be liquid! ESO PR Highlights 2007 This is a clickable map. These are only some of the press releases issued by ESO in 2007. For a full listing, please go to ESO 2007 page. In our own Solar System also, astronomers made stunning breakthroughs with ESO's telescopes, observing the effect of the light from the Sun on an asteroid's rotation (ESO 11/07), describing in unprecedented detail the double asteroid Antiope (ESO 18/07), peering at the rings of Uranus (ESO 37/07), discovering a warm south pole on Neptune (ESO 41/07), showing a widespread and persistent morning drizzle of methane over the western foothills of Titan's major continent (ESO 47/07), and studying in the greatest details the wonderful Comet McNaught (ESO 05/07 and 07/07). In the study of objects slightly more massive than planets, the VLT found that brown dwarfs form in a similar manner to normal stars (ESO 24/07). The VLT made it also possible to measure the age of a fossil star that was clearly born at the dawn of time (ESO 23/07). Other discoveries included reconstructing the site of a flare on a solar-like star (ESO 53/07), catching a star smoking (ESO 34/07), revealing a reservoir of dust around an elderly star (ESO 43/07), uncovering a flat, nearly edge-on disc of silicates in the heart of the magnificent Ant Nebula (ESO 42/07), finding material around a star before it exploded (ESO 31/07), fingerprinting the Milky Way (ESO 15/07), revealing a rich

  9. ESO PR Highlights in 2006

    Science.gov (United States)

    2007-01-01

    Last year proved to be another exceptional year for the European organisation for ground-based astronomy. ESO should begin the New Year with two new member states: Spain (PR 05/06) and the Czech Republic (PR 52/06). ESO PR Highlights 2006 2006 was a year of renovation and revolution in the world of planets. A new Earth-like exoplanet has been discovered (PR 03/06) using a network of telescopes from all over the world (including the Danish 1.54-m one at ESO La Silla). It is not the only child of this fruitful year: thanks to the combined use of ESO's Very Large Telescope (VLT) and La Silla instruments, a surprising system of twin giant exoplanets was found (PR 29/06), and a trio of Neptune-like planets hosted by a nearby star were identified (PR 18/06). These results open new perspectives on the search for habitable zones and on the understanding of the mechanism of planet formation. The VISIR instrument on the VLT has been providing unique information to answer this last question, by supplying a high resolution view of a planet-forming disc (PR 36/06). There are not only new members in the planets' register: during the General Assembly of the International Astronomical Union held in Prague (Czech Republic), it was decided that Pluto is not a planet anymore but a 'dwarf planet'. Whatever its status, Pluto still has a satellite, Charon, whose radius and density have been measured more accurately by observing a rare occultation from different sites, including Cerro Paranal (PR 02/06). The scientific community dedicated 2006 to the great physicist James Clerk Maxwell (it was the 175th anniversary of the birth): without his electromagnetic theory of light, none of the astonishing discoveries of modern physics could have been achieved. Nowadays we can look at distant galaxies in great detail: the GIRAFFE spectrograph on the VLT revealed that galaxies 6 billion years ago had the same amount of dark matter relative to stars than nowadays (PR 10/06), while SINFONI gave an

  10. Time-transgressive tunnel valley formation indicated by infill sediment structure, North Sea - the role of glaciohydraulic supercooling

    DEFF Research Database (Denmark)

    Kristensen, Thomas Bojer; Piotrowski, Jan; Huuse, Mads

    2008-01-01

    , the volumetrically most important and structurally most distinct, is composed of clinoform reflections downlapping axially up-valley (up-ice), Facies II is composed of near-horizontal, continuous and well layered reflections onlapping the clinoform reflections and the valley walls and Facies III is composed...... of clinoform reflections downlapping axially down-valley (down-ice). A model of formation of this sediment architecture is proposed, in which valley incision and infill are causally linked. It is proposed that Facies I is related to glaciohydraulic supercooling of subglacial meltwater in the distal parts...... of tunnel valleys. The valleys formed time-transgressively during ice retreat, whereby sediment eroded further up-ice was re-deposited along adverse subglacial slopes of the valleys close to the ice margin. The formation of Facies II and III is related to the deposition in proglacial basins during final...

  11. Sediment Acoustics

    National Research Council Canada - National Science Library

    Stoll, R

    2001-01-01

    ... variables such as porosity and grain-size distribution. The model is based on the classical Biot theory extended to take into account various mechanisms of energy loss that are known to be important in marine sediments...

  12. Visual Sedimentation

    OpenAIRE

    Huron, Samuel; Vuillemot, Romain; Fekete, Jean-Daniel

    2013-01-01

    International audience; We introduce Visual Sedimentation, a novel design metaphor for visualizing data streams directly inspired by the physical process of sedimentation. Visualizing data streams (e. g., Tweets, RSS, Emails) is challenging as incoming data arrive at unpredictable rates and have to remain readable. For data streams, clearly expressing chronological order while avoiding clutter, and keeping aging data visible, are important. The metaphor is drawn from the real-world sedimentat...

  13. Evolution of ice-dammed proglacial lakes in Última Esperanza, Chile: implications from the late-glacial R1 eruption of Reclús volcano, Andean Austral Volcanic Zone Evolución de lagos proglaciales embalsados por hielo en Última Esperanza, Chile: Implicancias de la explosión volcánica tardiglacial R1 del volcán Reclús, Zona Volcánica Austral Andina

    National Research Council Canada - National Science Library

    Charles R Stern; Patricio I Moreno; Rodrigo Villa-Martínez; Esteban A Sagredo; Alfredo Prieto; Rafael Labarca

    2011-01-01

    .... The geographic and stratigraphic distribution of Rl also place constraints on the evolution of the ice-dammed proglacial lake that existed east of the cordillera in this area between the termination...

  14. Fluvial sediment transport in a glacier-fed high-mountain river (Riffler Bach, Austrian Alps)

    Science.gov (United States)

    Morche, David; Weber, Martin; Faust, Matthias; Schuchardt, Anne; Baewert, Henning

    2017-04-01

    High-alpine environments are strongly affected by glacier retreat since the Little Ice Age (LIA). Due to ongoing climate change the hydrology of proglacial rivers is also influenced. It is expected that the growing proportions of snow melt and rainfall events will change runoff characteristics of proglacial rivers. Additionally, the importance of paraglacial sediment sources in recently deglaciating glacier forefields is increasing, while the role of glacial erosion is declining. Thus complex environmental conditions leading to a complex pattern of fluvial sediment transport in partly glaciated catchments of the European Alps. Under the umbrella of the joint PROSA-project the fluvial sediment transport of the river Riffler Bach (Kaunertal, Tyrol, Austria) was studied in 3 consecutive ablation seasons in order to quantify sediment yields. In June 2012 a probe for water level and an automatic water sampler (AWS) were installed at the outlet of the catchment (20km2). In order to calculate annual stage-discharge-relations by the rating-curve approach, discharge (Q) was repeatedly measured with current meters and by salt dilution. Concurrent to the discharge measurements bed load was collected using a portable Helley-Smith sampler. Bed load samples were weighted and sieved in the laboratory to gain annual bed load rating curves and grain size distributions. In total 564 (2012: 154, 2013: 209, 2014: 201) water samples were collected and subsequently filtered to quantify suspended sediment concentrations (SSC). Q-SSC-relations were calculated for single flood events due to the high variability of suspended sediment transport. The results show a high inter- and intra-annual variability of solid fluvial sediment transport, which can be explained by the characteristics of suspended sediment transport. Only 13 of 22 event-based Q-SSC-relations show causal dependency. In 2012, during a period with multiple pluvial-induced peak discharges most sediment was transported. On the

  15. The Effects of Vegetation Succession and Landscape on the Evolution of Soil Properties: A Chronosequence Study Along the Proglacial Area of Skaftafellsjökull Glacier, SE Iceland

    Science.gov (United States)

    Vilmundardóttir, O. K.; Gísladóttir, G.; Lal, R.

    2014-12-01

    On young soils developing along the recessional path left by the Skaftafellsjökull glacier, SE-Iceland, we investigated the soil development, vegetation succession and landscape representing an age chronosequence of 120 years. In total, 54 sampling sites were distributed along three moraines representing surfaces exposed for 8, 65 and 120 years. For comparison, soil samples were collected from nearby birch woodlands, representing soils in a mature ecosystem likely to establish on the moraines in the future. The youngest moraines were sparsely vegetated with only 10% cover of mosses and grasses. The plant cover increased to 67% after 120 years, and was characterized by mosses (38%), dwarf shrubs (20%) and low growing birch (3.5%). Consequently, the soil formed over 120 years contained 1.1 kg C m-2 in the surface layer (0-10 cm), or about one third of the 3.2 kg C m-2 in soil under the woodlands. The N stock was estimated at 0.06 kg N m-2after 120 yrs, almost one fourth of that under the woodlands. The data suggest that landscape affects vegetation establishment and in turn, both landscape and vegetation affect soil development. Thus, concentrations of soil organic carbon (SOC), N and noncrystalline oxalate extractable Al and Fe were higher within depressions than on ridges and slopes. The comparison of SOC stock in the moraine-derived soils with that under the birch woodlands showed that the young proglacial soils still have a large potential to accrete SOC within the developing pedosphere. With the observed accrual rate of 9.1 g C m-2 yr-1in the top 10 cm, it may take the moraine soils an additional 220 yrs to accrue SOC stocks comparable with those under the birch forest. Given the fact that all Icelandic glaciers are receding, assessing SOC sequestration in new soil formation may be important to off-setting some of anthropogenic emissions. The research is funded by the University of Iceland Doctoral Fund, the University of Iceland Trust Fund, the Landsvirkjun

  16. Using an Electronic Highlighter to Eliminate the Negative Effects of Pre-Existing, Inappropriate Highlighting

    Science.gov (United States)

    Gier, Vicki; Kreiner, David; Hudnell, Jason; Montoya, Jodi; Herring, Daniel

    2011-01-01

    The purpose of the present experiment was to determine whether using an active learning technique, electronic highlighting, can eliminate the negative effects of pre-existing, poor highlighting on reading comprehension. Participants read passages containing no highlighting, appropriate highlighting, or inappropriate highlighting. We hypothesized…

  17. Laboratory for Atmospheres: 2006 Technical Highlights

    Science.gov (United States)

    Stewart, Richard W.

    2007-01-01

    The 2006 Technical Highlights describes the efforts of all members of the Laboratory for Atmospheres. Their dedication to advancing Earth science through conducting research, developing and running models, designing instruments, managing projects, running field campaigns, and numerous other activities, are highlighted in this report.

  18. Sediment Acoustics.

    Science.gov (United States)

    1980-04-02

    approximately one grain size (0.35 mm) out of 600 grain size total. The experiment was repeated with a 2.54 cm thick layer of water filled polyurethane foam ...Kaolinite Clay for Shear Waves 70 it vi .- m -77- I. INTRODUCTION A determination of the viscoelastic properties of ocean sediments can be made by...temperature of these additional viscoelastic properties have not been studied in detail. This section contains shear wave and compressional wave data

  19. Using Highlighting to Train Attentional Expertise.

    Science.gov (United States)

    Roads, Brett; Mozer, Michael C; Busey, Thomas A

    2016-01-01

    Acquiring expertise in complex visual tasks is time consuming. To facilitate the efficient training of novices on where to look in these tasks, we propose an attentional highlighting paradigm. Highlighting involves dynamically modulating the saliency of a visual image to guide attention along the fixation path of a domain expert who had previously viewed the same image. In Experiment 1, we trained naive subjects via attentional highlighting on a fingerprint-matching task. Before and after training, we asked subjects to freely inspect images containing pairs of prints and determine whether the prints matched. Fixation sequences were automatically scored for the degree of expertise exhibited using a Bayesian discriminative model of novice and expert gaze behavior. Highlighted training causes gaze behavior to become more expert-like not only on the trained images but also on transfer images, indicating generalization of learning. In Experiment 2, to control for the possibility that the increase in expertise is due to mere exposure, we trained subjects via highlighting of fixation sequences from novices, not experts, and observed no transition toward expertise. In Experiment 3, to determine the specificity of the training effect, we trained subjects with expert fixation sequences from images other than the one being viewed, which preserves coarse-scale statistics of expert gaze but provides no information about fine-grain features. Observing at least a partial transition toward expertise, we obtain only weak evidence that the highlighting procedure facilitates the learning of critical local features. We discuss possible improvements to the highlighting procedure.

  20. Highlight: Knowledge-sharing meeting examines sustainability ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    2016-04-14

    sharing meeting on September 30, 2015 to highlight the major findings of the IDRC-supported project "Improving food and livelihood security in Punjab through water-energy-agriculture management under climate change and ...

  1. Highlight: Knowledge-sharing meeting examines sustainability ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    2015-09-30

    sharing meeting on September 30, 2015 to highlight the major findings of the IDRC-supported project "Improving food and livelihood security in Punjab through water-energy-agriculture management under climate change and ...

  2. Wood Machining Highlights, 1972 and 1973

    Science.gov (United States)

    C.W. McMillin

    1975-01-01

    Important wood machining research published during 1972 and 1973 is highlighted to provide the reader with a concise summary of activity in 17 fields of endeavor. The review is based on 427 references and contains 154 citations.

  3. Study Highlights the Beauty Industry's Ugly Side

    Science.gov (United States)

    ... html Study Highlights the Beauty Industry's Ugly Side Cosmetics, personal care products get little regulatory scrutiny To ... found that's not always the case. And, because cosmetics are woefully underregulated in the United States, and ...

  4. Last millenium environmental changes in Lake Bertrand sediments, Chilean Patagonia

    Science.gov (United States)

    Sacré, V.; Fagel, N.; Schmidt, S.; Alvarez, D.; Araneda, A.; Urrutia, R.

    2012-04-01

    Our study focuses on a multiproxy analysis of sedimentary records from Lago Bertrand (area 50 km2; 227 masl; 46°55'S 72°50'W). Three cores were retrieved during fieldtrips in 2009 and 2011 with an Uwitec gravity corer. One core was collected in the main lake (LBt09, 102 cm) and two others in a lateral extension (LBb11-A, 162 cm and LBb11-B, 156 cm). Data 210Pb and 137Cs give average sedimentation rates of 2 mm/yr for the upper core section from the main lake, allowing a decennial resolution. Our aim is to document the climatic variability during the last millennium in Northern Patagonia and its impact on the environment. Lago Bertrand is separated from a pro-glacial lake (Lago Plomo) by a morainic barrier. The sediments of this lake are mainly composed of clayed silts and very few sandy silts. In the cores from the Eastern branch of Lago Bertrand, X-ray radiographies and magnetic susceptibility profiles evidence well-defined pluri-millimetric laminations with organic-rich layers, especially in the central core section. In the main lake, X-ray radiographies show diffuse pluri-millimetric laminations while magnetic susceptibility profiles do not confirm it. The sediments of the main lake appear more homogeneous with less organic-rich layers. They are characterized by low C/N ratio (10), supporting an important aquatic productivity; high inorganic content (90-95% of the bulk sediment); two peaks in the biological silica profile; and abundant diatoms (50-100 µm). According to the age model, the changes in aquatic productivity occurred between 1700 and 1850 AD. The cores from the Eastern branch of Lago Bertrand are under investigation to confirm the extension of the sedimentological changes observed in the main lake. The main sedimentological change observed in Lago Bertrand occurs during an interval equivalent to a part of the Little Ice Age. A similar biogenic silica-rich layer was also recorded in another relatively distant lake (Lago Thompson at 45°30'S, 72°47

  5. Using Highlighting to Train Attentional Expertise.

    Directory of Open Access Journals (Sweden)

    Brett Roads

    Full Text Available Acquiring expertise in complex visual tasks is time consuming. To facilitate the efficient training of novices on where to look in these tasks, we propose an attentional highlighting paradigm. Highlighting involves dynamically modulating the saliency of a visual image to guide attention along the fixation path of a domain expert who had previously viewed the same image. In Experiment 1, we trained naive subjects via attentional highlighting on a fingerprint-matching task. Before and after training, we asked subjects to freely inspect images containing pairs of prints and determine whether the prints matched. Fixation sequences were automatically scored for the degree of expertise exhibited using a Bayesian discriminative model of novice and expert gaze behavior. Highlighted training causes gaze behavior to become more expert-like not only on the trained images but also on transfer images, indicating generalization of learning. In Experiment 2, to control for the possibility that the increase in expertise is due to mere exposure, we trained subjects via highlighting of fixation sequences from novices, not experts, and observed no transition toward expertise. In Experiment 3, to determine the specificity of the training effect, we trained subjects with expert fixation sequences from images other than the one being viewed, which preserves coarse-scale statistics of expert gaze but provides no information about fine-grain features. Observing at least a partial transition toward expertise, we obtain only weak evidence that the highlighting procedure facilitates the learning of critical local features. We discuss possible improvements to the highlighting procedure.

  6. Remote effects of highlights on gloss perception.

    Science.gov (United States)

    Berzhanskaya, Julia; Swaminathan, Gurumurthy; Beck, Jacob; Mingolla, Ennio

    2005-01-01

    The perception of a glossy surface in a static monochromatic image can occur when a bright highlight is embedded in a compatible context of shading and a bounding contour. Some images naturally give rise to the impression that a surface has a uniform reflectance, characteristic of a shiny object, even though the highlight may only cover a small portion of the surface. Nonetheless, an observer's impression of gloss may be partial and nonuniform at image regions outside of a highlight. A rating scale and small probe points indicating image locations were used to investigate the differential perception of gloss within a single object. Gloss ratings given by observers were not uniform across a surface, but decreased as a function of distance from a highlight. When, by design, the distance from a highlight was uncoupled from the luminance value at corresponding probe points, the decrease in rated gloss correlated more with distance than with luminance change. Experiments also indicated that gloss ratings may change as a function of estimated surface distance, rather than as a function of image distance. Surface continuity affected gloss ratings, suggesting that surface and gloss processing are closely related.

  7. EM international activities. February 1997 highlights

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-02-01

    EM International Highlights is a brief summary of on-going international projects within the Department of Energy`s Office of Environmental Management (EM). This document contains sections on: Global Issues, activities in Western Europe, activities in central and Eastern Europe, activities in Russia, activities in Asia and the Pacific Rim, activities in South America, activities in North America, and International Organizations.

  8. Naval Postgraduate School Historical Highlights 2010

    OpenAIRE

    Sanders, John

    2010-01-01

    The Dudley Knox Library provides historical highlights for the monthly publication, Update NPS. These "caption stories" blend archival photos and documents into a concise storyline to showcase the origin and evolution of NPS as well as achievements of the institution's leaders, faculy and alumni.

  9. Naval Postgraduate School Historical Highlights 2009

    OpenAIRE

    Sanders, John

    2009-01-01

    The Dudley Knox Library provides historical highlights for the monthly publication, Update NPS. These "caption stories" blend archival photos and documents into a concise storyline to showcase the origin and evolution of NPS as well as achievements of the institution's leaders, faculy and alumni.

  10. Naval Postgraduate School Historical Highlights 2008

    OpenAIRE

    Sanders, John

    2008-01-01

    The Dudley Knox Library provides historical highlights for the monthly publication, Update NPS. These "caption stories" blend archival photos and documents into a concise storyline to showcase the origin and evolution of NPS as well as achievements of the institution's leaders, faculy and alumni.

  11. Naval Postgraduate School Historical Highlights 2012

    OpenAIRE

    Sanders, John

    2012-01-01

    The Dudley Knox Library provides historical highlights for the monthly publication, Update NPS. These "caption stories" blend archival photos and documents into a concise storyline to showcase the origin and evolution of NPS as well as achievements of the institution's leaders, faculy and alumni.

  12. Palliativedrugs.com therapeutic highlights: gabapentin

    Directory of Open Access Journals (Sweden)

    Twycross Robert

    2003-01-01

    Full Text Available This is the second in a series of highlights drawn from the www.palliativedrugs.com website. The website provides free access to the Palliative Care Formulary, a monthly newsletter and a bulletin board for advice to be given and received. With almost 10,000 professional members it is the largest palliative care resource of its kind.

  13. Research highlights: printing the future of microfabrication.

    Science.gov (United States)

    Tseng, Peter; Murray, Coleman; Kim, Donghyuk; Di Carlo, Dino

    2014-05-07

    In this issue we highlight emerging microfabrication approaches suitable for microfluidic systems with a focus on "additive manufacturing" processes (i.e. printing). In parallel with the now-wider availability of low cost consumer-grade 3D printers (as evidenced by at least three brands of 3D printers for sale in a recent visit to an electronics store in Akihabara, Tokyo), commercial-grade 3D printers are ramping to higher and higher resolution with new capabilities, such as printing of multiple materials of different transparency, and with different mechanical and electrical properties. We highlight new work showing that 3D printing (stereolithography approaches in particular) has now risen as a viable technology to print whole microfluidic devices. Printing on 2D surfaces such as paper is an everyday experience, and has been used widely in analytical chemistry for printing conductive materials on paper strips for glucose and other electrochemical sensors. We highlight recent work using electrodes printed on paper for digital microfluidic droplet actuation. Finally, we highlight recent work in which printing of membrane-bound droplets that interconnect through bilayer membranes may open up an entirely new approach to microfluidic manufacturing of soft devices that mimic physiological systems.

  14. Brookhaven highlights - Brookhaven National Laboratory 1995

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-09-01

    This report highlights research conducted at Brookhaven National Laboratory in the following areas: alternating gradient synchrotron; physics; biology; national synchrotron light source; department of applied science; medical; chemistry; department of advanced technology; reactor; safety and environmental protection; instrumentation; and computing and communications.

  15. South-central Alaska forests: inventory highlights.

    Science.gov (United States)

    Sally Campbell; Willem W.S. van Hees; Bert. Mead

    2005-01-01

    This publication presents highlights of a recent south-central Alaska inventory conducted by the Pacific Northwest Research Station Forest Inventory and Analysis Program (USDA Forest Service). South-central Alaska has about 18.5 million acres, of which one-fifth (4 million acres) is forested. Species diversity is greatest in closed and open Sitka spruce forests, spruce...

  16. Brookhaven highlights, October 1979-September 1980

    Energy Technology Data Exchange (ETDEWEB)

    1980-01-01

    Highlights are given for the research areas of the Brookhaven National Laboratory. These areas include high energy physics, physics and chemistry, life sciences, applied energy science (energy and environment, and nuclear energy), and support activities (including mathematics, instrumentation, reactors, and safety). (GHT)

  17. 2013 Ukraine Enterprise Survey : Country Highlights

    OpenAIRE

    World Bank; International Finance Corporation

    2014-01-01

    The World Bank interviewed a representative sample of the private sector, composed of 1,002 establishments, between January and November 2013. The enterprise survey covers several aspects of the business environment as well as performance measures for each firm. This report presents following highlights from the survey: firm performance indicators point to a significant deterioration over ...

  18. Hillslope failure and paraglacial reworking of sediments in response to glacier retreat, Fox Valley, New Zealand.

    Science.gov (United States)

    McColl, Samuel T.; Fuller, Ian C.; Anderson, Brian; Tate, Rosie

    2017-04-01

    Climate and glacier fluctuations influence sediment supply to glacier forelands, which in turn influences down-valley hazards to infrastructure and tourism within glacier forelands. At Fox Glacier, one of New Zealand's most iconic and popular glaciers, rapid retreat has initiated a range of hillslope and valley floor responses, that present a cascade of hazards and changes that need to be carefully managed. Fox Glacier has retreated many kilometres historically, with 2.6 km of retreat since the mid-20th century, and a phase of rapid retreat of 50-340 m per year since 2009. To study the system response to past and ongoing glacial retreat at the Fox valley, morphological changes are being observed using time-lapse photography and the annual collection of high-resolution digital elevation models (DEMs) and orthophoto mosaics. The DEMs are being produced using Structure from Motion photogrammetry from UAV/RPAS and helicopter platforms, and are being used, along with manual ground surveying, to produce ground surface change models (DoDs; DEMs of Difference) and sediment budgets for the valley. Results from time-lapse photography and DoDs show that glacial retreat has initiated destabilisation and (mostly chronic) mass movement of surficial glacial sediments on the valley slopes near the glacier terminus. Alluvial fans farther down valley are actively growing, reworking glacial and landslide sediments from tributary catchments. These paraglacial sediments being delivered to the proglacial river from the glacier terminus and alluvial fans are driving aggradation of the valley floor of decimetres to metres per year and maintaining a highly dynamic braid plain. Valley floor changes also include the melting of buried dead ice, which are causing localised subsidence at the carpark and one of the alluvial fans. The unstable slopes and active debris fans, aggrading and highly active river channel, ground subsidence, add to the spectacle but also the hazards of the Fox valley

  19. Trends and highlights of VCI 2004

    CERN Document Server

    Fabjan, Christian Wolfgang

    2004-01-01

    This report attempts to summarize the presentations given at this conference. Topics related to R&D of gaseous and solid state detectors clearly point to several trends in particle physics instrumentation. More established techniques are represented by reports on recent experiments and facilities which can be considered the highlights in this research field. The extension of these techniques to space, arctic ice and deep sea are opening new frontiers of particle physics.

  20. Highlights from the LHC Energy frontier

    CERN Document Server

    Su, Dong; The ATLAS collaboration

    2017-01-01

    This presentation at the Lake Louise Winter Institute 2017 opening session will introduce the highlights of the recent ATLAS and CMS physics results during the 2015-2016 Run 2 at 13 TeV. The physics topics include electroweak physics, top quark, new physics searches and Higgs physics to lead out the sessions to follow on these topics. As the opening talk, brief status of LHC and the ATLAS and CMS experiments will also be included.

  1. Physics highlights of a tau charm factory

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Romero, E.M. (CIEMAT Investigacion Basica, Div. Fisica de Particulas, Madrid (Spain))

    1993-06-07

    After the very recent proposal from the Spanish Government to build a Tau-Charm Factory, in this talk, I give a fast overview of the characteristics and experimental conditions available in such a laboratory. Some of the more relevant measurements unique to this facility are highlighted for the three main fields of experimentation: Tau physics, Charmed mesons physics and the J/[Psi] and [Psi]' resonances. (orig.)

  2. Action Classification and Highlighting in Videos

    OpenAIRE

    Torabi, Atousa; Sigal, Leonid

    2017-01-01

    Inspired by recent advances in neural machine translation, that jointly align and translate using encoder-decoder networks equipped with attention, we propose an attentionbased LSTM model for human activity recognition. Our model jointly learns to classify actions and highlight frames associated with the action, by attending to salient visual information through a jointly learned soft-attention networks. We explore attention informed by various forms of visual semantic features, including tho...

  3. Selected Highlights from Precision Studies in ATLAS

    CERN Document Server

    Beck, Hans Peter; The ATLAS collaboration

    2014-01-01

    Recent highlights on precision measurements in proton-proton collisions at 7 and 8 TeV with the ATLAS detector are presented: the production cross section of jets, W and Z bosons, multi-bosons and top quark pairs, as well as single top production. Furthermore, the production of W and Z bosons and top quarks in association with jets is discussed and compared to state-of-art theory calculations. The latest measurements of the top quark mass and other properties, together with Standard Model parameters, will be reviewed.

  4. Highlights and Perspectives from the CMS Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Butler, Joel Nathan [Fermilab

    2017-09-09

    In 2016, the Large Hadron Collider provided proton-proton collisions at 13 TeV center-of-mass energy and achieved very high luminosity and reliability. The performance of the CMS Experiment in this running period and a selection of recent physics results are presented. These include precision measurements and searches for new particles. The status and prospects for data-taking in 2017 and a brief summary of the highlights of the High Luminosity (HL-LHC) upgrade of the CMS detector are also presented.

  5. Astonishing the wild pigs highlights of technology

    CERN Document Server

    Trueb, Lucien F; Stuber, Fred A

    2015-01-01

    A hydraulic machine for astonishing wild pigs was one of the many technological highlights the author encountered in the course of his career as a research scientist and science writer. Writing a book about them, never taking more (or less) than two printed pages for each of 146 subjects was a very special challenge. The book covers fundamentally important achievements of technology that directly impacted mankind or even profoundly changed it. Many of those highlights are quite new, at least one of them (power generation by nuclear fusion) is not available yet. But particularly ingenious things dating way back were also included, as they are the base of our technical civilization Good examples are ceramics as well as copper, bronze and iron; whole periods of history have been named for the latter three. The analog computer of Antikythera used for stellar navigation was made some 2100 years ago, gunpowder was used in China as early as 1044 A.D., the astronomical clock in the Strasburg cathedral was built in th...

  6. The missing piece: sediment records in remote Mountain lakes confirm glaciers being secondary sources of persistent organic pollutants.

    Science.gov (United States)

    Schmid, Peter; Bogdal, Christian; Blüthgen, Nancy; Anselmetti, Flavio S; Zwyssig, Alois; Hungerbühler, Konrad

    2011-01-01

    After atmospheric deposition and storage in the ice, glaciers are temporary reservoirs of persistent organic pollutants (POPs). Recently, the hypothesis that melting glaciers represent secondary sources of these pollutants has been introduced by investigations of the historical trend of POPs in a dated sediment core from the proglacial Alpine Lake Oberaar. Here, the hypothesis is further confirmed by the comparison of sediment data gathered from two Alpine lakes with a glaciated and a nonglaciated hydrological catchment. The two lakes (Lake Engstlen and Lake Stein in the Bernese Alps in Switzerland) are situated only 8 km apart at similar altitude and in the same meteorological catchment. In the nonglacial lake sediment of Lake Engstlen, PCBs and DDT (polychlorinated biphenyls and dichlorodiphenyl trichloroethane) levels culminated with the historic usage of these chemicals some 30-50 years ago. In the glacial Lake Stein, this peak was followed by a reincrease in the 1990s, which goes along with the accelerated melting of the adjacent glacier. This study confirms the hypothesis of glaciers being a secondary source of these pollutants and is in accordance with the earlier findings in Lake Oberaar.

  7. Rock magnetic properties of sediments from Lake Sanabria and its catchment (NW Spain): paleoenvironmental implications

    Science.gov (United States)

    Larrasoaña, J. C.; Borruel, V.; Gómez-Paccard, M.; Rico, M.; Valero-Garces, B.; Moreno-Caballud, A.; Soto, R.

    2013-12-01

    Lake Sanabria is located in the NW Spanish mountains at 1000 m a.s.l., and constitutes the largest lake of glacial origin in the Iberian Peninsula. Here we present an environmental magnetic study of a Late Pleistocene-Holocene sediment core from Lake Sanabria and from different lithologies that crop out in its catchment, which includes Paleozoic plutonic, metamorphic and vulcanosedimentary rocks, and Quaternary deposits of glacial origin. This study was designed to complement sedimentologic and geochemical studies aimed at unraveling the climatic evolution of the NW Iberian Peninsula during the last deglaciation. Our results indicate that magnetite and pyrrhotite dominate the magnetic assemblage of both the sediments from the lower half of the studied sequence (25.6 - 13 cal kyr BP) deposited in a proglacial environment, and the Paleozoic rocks that make up most of the catchment of the lake. The occurrence of these minerals both in the catchment rocks and in the lake sediments indicates that sedimentation was then driven by the erosion of a glacial flour, which suffered minimal chemical transformation in response to a rapid and short routing to the lake. Sediments from the upper half of the studied sequence, accumulated after 12.4 cal kyr BP in a fluviolacustrine environment, contain magnetite and greigite. This points to a prominent role of post-depositional reductive dissolution, driven by a sharp increase in the accumulation of organic matter into the lake and the creation of anoxic conditions in the sediments, in shaping the magnetic assemblage of Holocene sediments. Pyrrhotite is stable under reducing conditions as opposed to magnetite, which is unstable. We therefore interpret that previous pedogenic processes occurred in the then deglaciated catchment of the lake were responsible for the oxidation of pyrrhotite and authigenic formation of magnetite, which survived subsequent reductive diagenesis given its initial larger concentrations. This interpretation is

  8. Monitoring of metals in Tilapia nilotica tissues, bottom sediments ...

    African Journals Online (AJOL)

    Tilapia (Tilapia nilotica), bottom sediments and water were collected from Nworie River and Oguta Lake. The muscle, liver and gills of the fish as well as the bottom sediments and water were analysed for Al, Cr, Cd, Pb, As, Zn, Mn, Co, Se, Cu, Ni and Fe using atomic absorption spectrophotometer to highlight the importance ...

  9. Acoustic architecture of glaciolacustrine sediments deformed during zonal stagnation of the Laurentide Ice Sheet; Mazinaw Lake, Ontario, Canada

    Science.gov (United States)

    Eyles, Nicholas; Doughty, Mike; Boyce, Joseph I.; Mullins, Henry T.; Halfman, John D.; Koseoglu, Berkant

    2003-03-01

    In North America, the last (Laurentide) Ice Sheet retreated from much of the Canadian Shield by 'zonal stagnation'. Masses of dead ice, severed from the main ice sheet by emerging bedrock highs, downwasted in situ within valleys and lake basins and were commonly buried by sediment. Consequently, the flat sediment floors of many valleys and lakes are now pitted by steep-sided, enclosed depressions (kettle basins) that record the melt of stagnant ice blocks and collapse of sediment. At Mazinaw Lake in eastern Ontario, Canada, high-resolution seismic reflection, magnetic and bathymetric surveys, integrated with onland outcrop and hammer seismic investigations, were conducted to identify the types of structural disturbance associated with the formation of kettle basins in glaciolacustrine sediments. Basins formed as a result of ice blocks being trapped within a regionally extensive proglacial lake (Glacial Lake Iroquois ˜12,500 to 11,400 years BP) that flooded eastern Ontario during deglaciation. Kettles occur within a thick (>30 m) succession of parallel, high-frequency acoustic facies consisting of rhythmically laminated (varved?) Iroquois silty-clays. Iroquois strata underlying and surrounding kettle basins show large-scale normal faults, fractures, rotational failures and incoherent chaotically bedded sediment formed by slumping and collapse. Mazinaw Lake lies along part of the Ottawa Graben and while neotectonic earthquake activity cannot be entirely dismissed, deformation is most likely to have occurred as a result of the rapid melt of buried ice blocks. Seismic data do not fully penetrate the entire basin sediment fill but the structure and topography of bedrock can be inferred from magnetometer data. The location and shape of buried ice masses was closely controlled by the graben-like form of the underlying bedrock surface.

  10. High-resolution multitemporal measurement of rockglacier dynamics and periglacial sediment storage in the eastern Alps, Austria

    Science.gov (United States)

    Dusik, Jana-Marie; Haas, Florian; Heckmann, Tobias; Hilger, Ludwig; Neugirg, Fabian; Leopold, Matthias; Becht, Michael

    2013-04-01

    High alpine environments are subject to rapid change due to melting glaciers and permafrost. As a consequence, rockwalls and moraines experience destabilization and increased mobilization of sediment. The work presented here is part of the joint project PROSA (High-resolution measurements of morphodynamics in rapidly changing PROglacial Systems of the Alps) which deals with the calculation and quantification of the sediment budget for an alpine catchment situated in the Kaunertal, Austrian Alps. Rockglaciers are frequently appearing landforms in the Kaunertal and represent large sediment storages. Usually the sediment flux of rockglaciers is rather small, depending on their activity status. All activity forms of rockglaciers (active, inactive and relict) are present in the catchment area. Besides the highly active and well-known Ölgrube rockglacier, this work deals especially with the examination of the Riffeltal rockglacier which is situated on the opposite valley side. The activity status of the Riffeltal rockglacier is assessed and compared to the Ölgrube rockglacier with respect to the local parameters aspect, altitude, existence/absence of glaciers, geology and catchment area. Furthermore sediment volumes of both rockglaciers, their rates of movement and therefore their contribution to the sediment budget of the Kaunertal-catchment area is estimated. The internal structure of the Riffeltal rockglacier was inferred from geophysical measurements (refraction seismics, ground penetrating radar and electrical resistivity tomography). Temperature loggers were placed on and around the rockglacier before the first snowfall to measure the bottom temperature of snowcover (BTS) once per hour during winter, and BTS measurements will be performed with a probe in February, March and April to infer permafrost probability. Rockglacier dynamics are identified with the analysis of multitemporal orthophotos and digital elevation models, derived from high-resolution airborne

  11. LHC INAUGURATION, LHC Fest highlights: exhibition time!

    CERN Multimedia

    2008-01-01

    David Gross, one of the twenty-one Nobel Laureates who have participated in the project.Tuesday 21 October 2008 Accelerating Nobels Colliding Charm, Atomic Cuisine, The Good Anomaly, A Quark Somewhere on the White Paper, Wire Proliferation, A Tale of Two Liquids … these are just some of the titles given to artworks by Physics Nobel Laureates who agreed to make drawings of their prize-winning discoveries (more or less reluctantly) during a special photo session. Science photographer Volker Steger made portraits of Physics Nobel Laureates and before the photo sessions he asked them to make a drawing of their most important discovery. The result is "Accelerating Nobels", an exhibition that combines unusual portraits of and original drawings by twenty-one Nobel laureates in physics whose work is closely related to CERN and the LHC. This exhibition will be one of the highlights of the LHC celebrations on 21 October in the SM18 hall b...

  12. FY 1996 Congressional budget request: Budget highlights

    Energy Technology Data Exchange (ETDEWEB)

    1995-02-01

    The FY 1996 budget presentation is organized by the Department`s major business lines. An accompanying chart displays the request for new budget authority. The report compares the budget request for FY 1996 with the appropriated FY 1995 funding levels displayed on a comparable basis. The FY 1996 budget represents the first year of a five year plan in which the Department will reduce its spending by $15.8 billion in budget authority and by $14.1 billion in outlays. FY 1996 is a transition year as the Department embarks on its multiyear effort to do more with less. The Budget Highlights are presented by business line; however, the fifth business line, Economic Productivity, which is described in the Policy Overview section, cuts across multiple organizational missions, funding levels and activities and is therefore included in the discussion of the other four business lines.

  13. Highlights from the 9th Cachexia Conference.

    Science.gov (United States)

    Ebner, Nicole; von Haehling, Stephan

    2017-06-01

    This article highlights updates of pathways as well as pre-clinical and clinical studies into the field of wasting disorders that were presented at the 9th Cachexia Conference held in Berlin, Germany, December 2016. This year, some interesting results from clinical trials and different new therapeutic targets were shown. This article presents the biological and clinical significance of different markers and new diagnostic tools and cut-offs of detecting skeletal muscle wasting. Effective treatments of cachexia and wasting disorders are urgently needed in order to improve the patients' quality of life and their survival. © 2017 The Authors. Journal of Cachexia, Sarcopenia and Muscle published by John Wiley & Sons Ltd on behalf of the Society on Sarcopenia, Cachexia and Wasting Disorders.

  14. Physical Sciences 2007 Science & Technology Highlights

    Energy Technology Data Exchange (ETDEWEB)

    Hazi, A U

    2008-04-07

    The Physical Sciences Directorate applies frontier physics and technology to grand challenges in national security. Our highly integrated and multidisciplinary research program involves collaborations throughout Lawrence Livermore National Laboratory, the National Nuclear Security Administration, the Department of Energy, and with academic and industrial partners. The Directorate has a budget of approximately $150 million, and a staff of approximately 350 employees. Our scientists provide expertise in condensed matter and high-pressure physics, plasma physics, high-energy-density science, fusion energy science and technology, nuclear and particle physics, accelerator physics, radiation detection, optical science, biotechnology, and astrophysics. This document highlights the outstanding research and development activities in the Physical Sciences Directorate that made news in 2007. It also summarizes the awards and recognition received by members of the Directorate in 2007.

  15. Highlights from NuFact05

    CERN Multimedia

    CERN. Geneva; Landua, Rolf

    2005-01-01

    The 7th International Workshop on Neutrino Factories and Superbeams was held in Frascati in June 2005 with nearly 200 participants. The most recent progress in the design of future neutrino facilities was described, including novel ideas in detectors, and many issues were raised. The International Scoping Study (ISS) for a future Neutrino Facility which would incorporate a Neutrino Factory and/or a high intensity Neutrino Superbeam was launched at that occasion. Built upon previous studies in the USA, Europe and Japan, it will aim to i) define the physics case and a baseline design for such a facility including the related neutrino detection systems, ii) identify the required research and development programme and iii) perform comparisons with other options such as beta beams. The highlights of the meeting and the upcoming studies will be presented.

  16. LHC Highlights, from dream to reality

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    The idea of the Large Hadron Collider (LHC) was born in the early 1980s. Although LEP (CERN’s previous large accelerator) was still under construction at that time, scientists were already starting to think about re-using the 27-kilometre ring for an even more powerful machine. Turning this ambitious scientific plan into reality proved to be an immensely complex task. Civil engineering work, state-of-the-art technologies, a new approach to data storage and analysis: many people worked hard for many years to accomplish all this.   Here are some of the highlights: 1984. A symposium organized in Lausanne, Switzerland, is the official starting point for the LHC. LHC prototype of the two beam pipes (1992). 1989. The first embryonic collaborations begin. 1992. A meeting in Evian, France, marks the beginning of the LHC experiments. 1994. The CERN Council approves the construction of the LHC accelerator. 1995. Japan becomes an Observer of CERN and announces a financial contribution to ...

  17. Research highlights: microfluidically-fabricated materials.

    Science.gov (United States)

    Koh, Jaekyung; Wu, Chueh-Yu; Kittur, Harsha; Di Carlo, Dino

    2015-10-07

    Polymer particles with precise shapes or chemistries are finding unique uses in a variety of applications, including tissue engineering, drug delivery, barcoding, and diagnostic imaging. Microfluidic systems have been and are continuing to play a large role in enabling the precision synthesis of designer particles in a uniform manner. To expand the impact of these microfluidic-fabricated materials additional fundamental capabilities should still be developed. The capability to fabricate microparticles with complex three-dimensional shapes and increase the production rate of particles to an industrial scale will allow evaluation of shaped particles in a range of new applications to enhance biological, magnetic, optical, surface wetting, as well as other interfacial or mechanical properties of materials. Here we highlight work applying large collections of simple spherical microgels, with unique surface chemistry that allows in situ particle-particle annealing, to form microporous injectable scaffolds for accelerated tissue regeneration. We also report on two other techniques that are addressing the ability to create 3D-shaped microparticles by first sculpting a fluid precursor stream, and increasing the rate of production of particles using contact lithography to millions of particles per hour. The combination of these capabilities and the applications they will enable suggest a bright future for microfluidics in making the next materials.

  18. STS-114 Flight Day 9 Highlights

    Science.gov (United States)

    2005-01-01

    The highlight of Day 9 is the third extravehicular activity (EVA) of the STS-114 mission (Commander Eileen Collins, Pilot James Kelly, Mission Specialists Soichi Noguchi, Stephen Robinson, Andrew Thomas, Wendy Lawrence, and Charles Camarda). Astronauts Noguchi and Robinson are seen preparing for the EVA in the closed payload bay of Space Shuttle Discovery; on the EVA they install on the International Space Station (ISS) a Materials on the International Space Station Experiments (MISSE) unit, an External Stowage Platform (ESP-2), and a wireless antenna. The astronauts are seen working on the ISS under different lighting conditions, and use a pistol-grip tool to remove ESP-2 from the shuttle payload bay. The Space Station Remote Manipulator System then carries Robinson to the underside of the Discovery orbiter, where he communicates with Mission Control during the delicate and unprecedented removal of gap fillers from between the shuttle's tiles. Before and the after the EVA the video includes views of a damaged thermal blanket beneath the shuttle cockpit window. Other views of the shuttle include pans along the underside and topside by the Orbiter Boom Sensor System. The video also includes a view from orbit of Kazakhstan.

  19. Highlights from past and future physics

    CERN Multimedia

    Daisy Yuhas

    2009-01-01

    A two-day symposium was held at CERN on 3 and 4 December in celebration of the fiftieth anniversary of the Proton Synchrotron and the twentieth anniversary of LEP. The symposium, entitled “From the Proton Synchrotron to the Large Hadron Collider- 50 Years of Nobel Memories in High-Energy Physics”, included a series of seminars reflecting on the past fifty years in particle physics and an exhibition highlighting CERN’s research over this period.   Lyn Evans, LHC project leader, addressing the audience gathered in the Main Auditorium during the symposium that celebrated the 50 years of the PS and the 20 years of LEP.  The events were well attended on both days. Thursday’s reception, to which the Director-General invited everyone working at CERN, attracted over 1200 people. The seminars drew about 500 people to the Main Auditorium and the Council Chamber each day, with at least as many on-line attendees. The symposium speakers, including thirteen No...

  20. AGILE Highlights after Six Years in Orbit

    Directory of Open Access Journals (Sweden)

    Carlotta Pittori

    2014-12-01

    Full Text Available AGILE is an ASI space mission in collaboration with INAF, INFN and CIFS, dedicated to the observation of the gamma-ray Universe in the 30 MeV - 50 GeV energy range, with simultaneous X-ray imaging capability in the 18-60 keV band. The AGILE satellite was launched on April 23rd, 2007, and produced several important scientic results, among which the unexpected discovery of strong ares from the Crab Nebula. This discovery won to the AGILE PI and the AGILE Team the Bruno Rossi Prize for 2012 by the High Energy Astrophysics division of the American Astronomical Society. Thanks to its sky monitoring capability and fast ground segment alert system, AGILE detected many Galactic and extragalactic sources: among other results AGILE discovered gamma-ray emission from the microquasar Cygnus X-3, detected many bright blazars, discovered several new gamma-ray pulsars, and discovered emission up to 100 MeV from Terrestrial Gamma-Ray Flashes. We present an overview of the main AGILE Data Center activities and the AGILE scientic highlights after 6 years of operations.

  1. STS-114 Flight Day 3 Highlights

    Science.gov (United States)

    2005-01-01

    Video coverage of Day 3 includes highlights of STS-114 during the approach and docking of Discovery with the International Space Station (ISS). The Return to Flight continues with space shuttle crew members (Commander Eileen Collins, Pilot James Kelly, Mission Specialists Soichi Noguchi, Stephen Robinson, Andrew Thomas, Wendy Lawrence, and Charles Camarda) seen in onboard activities on the fore and aft portions of the flight deck during the orbiter's approach. Camarda sends a greeting to his family, and Collins maneuvers Discovery as the ISS appears steadily closer in sequential still video from the centerline camera of the Orbiter Docking System. The approach includes video of Discovery from the ISS during the orbiter's Rendezvous Pitch Maneuver, giving the ISS a clear view of the thermal protection systems underneath the orbiter. Discovery docks with the Destiny Laboratory of the ISS, and the shuttle crew greets the Expedition 11 crew (Commander Sergei Krikalev and NASA ISS Science Officer and Flight Engineer John Phillips) of the ISS onboard the station. Finally, the Space Station Remote Manipulator System hands the Orbiter Boom Sensor System to its counterpart, the Shuttle Remote Manipulator System.

  2. Highlights from BNL and RHIC 2015

    CERN Document Server

    Tannenbaum, M J

    2016-01-01

    Highlights of news from Brookhaven National Laboratory (BNL) and results from the Relativistic Heavy Ion Collider (RHIC) in the period July 2014-June 2015 are presented. The news this year was mostly very positive. The major event at BNL was the startup and dedication of the new NSLS II, "the World's brightest Synchrotron Light Source". The operation of RHIC was outstanding with a polarized p+p run at $\\sqrt{s}=200$ GeV with integrated luminosity that exceeded the sum of all previous p+p integrated luminosity at this $\\sqrt{s}$. For the first time at RHIC asymmetric p+Au and p+Al runs were made but the p+Al run caused damage in the PHENIX forward detectors from quenches that were inadequately shielded for this first p+A run. This was also the 10th anniversary of the 2005 announcement of the Perfect Liquid Quark Gluon Plasma at RHIC and a review is presented of the discoveries leading to this claim. A new result on net-charge fluctuations (with no particle identification) from PHENIX based on previous scans ov...

  3. Sediment reworking rates in deep sediments of the Mediterranean Sea

    Energy Technology Data Exchange (ETDEWEB)

    Barsanti, M., E-mail: mattia.barsanti@enea.it [ENEA, Marine Environment Research Centre, La Spezia (Italy); Delbono, I., E-mail: ivana.delbono@enea.it [ENEA, Marine Environment Research Centre, La Spezia (Italy); Schirone, A., E-mail: antonio.schirone@enea.it [ENEA, Marine Environment Research Centre, La Spezia (Italy); Langone, L., E-mail: leonardo.langone@bo.ismar.cnr.it [CNR, ISMAR Istituto di Scienze Marine, U.O.S. Bologna (Italy); Miserocchi, S., E-mail: stefano.miserocchi@bo.ismar.cnr.it [CNR, ISMAR Istituto di Scienze Marine, U.O.S. Bologna (Italy); Salvi, S., E-mail: stefano.salvi@enea.it [ENEA, Research Centre Brasimone, Camugnano (Italy); Delfanti, R., E-mail: roberta.delfanti@enea.it [ENEA, Marine Environment Research Centre, La Spezia (Italy)

    2011-07-01

    Different pelagic areas of the Mediterranean Sea have been investigated in order to quantify physical and biological mixing processes in deep sea sediments. Herein, results of eleven sediment cores sampled at different deep areas (> 2000 m) of the Western and Eastern Mediterranean Sea are presented. {sup 210}Pb{sub xs} and {sup 137}Cs vertical profiles, together with {sup 14}C dating, are used to identify the main processes characterising the different areas and, finally, controlling mixing depths (SML) and bioturbation coefficients (D{sub b}). Radionuclide vertical profiles and inventories indicate that bioturbation processes are the dominant processes responsible for sediment reworking in deep sea environments. Results show significant differences in sediment mixing depths and bioturbation coefficients among areas of the Mediterranean Sea characterised by different trophic regimes. In particular, in the Oran Rise area, where the Almeria-Oran Front induces frequent phytoplankton blooms, we calculate the highest values of sediment mixing layers (13 cm) and bioturbation coefficients (0.187 cm{sup 2} yr{sup -1}), and the highest values of {sup 210}Pb{sub xs} and {sup 137}Cs inventories. Intermediate values of SML and D{sub b} ({approx} 6 cm and {approx} 0.040 cm{sup 2} yr{sup -1}, respectively) characterise the mesothrophic Algero-Balearic basin, while in the Southern Tyrrhenian Sea mixing parameters (SML of 3 cm and D{sub b} of 0.011 cm{sup 2} yr{sup -1}) are similar to those calculated for the oligotrophic Eastern Mediterranean (SML of 2 cm and D{sub b} of {approx} 0.005 cm{sup 2} yr{sup -1}). - Research highlights: {yields} Physical and biological mixing processes in the Mediterranean Sea are investigated. {yields} Results of 11 sediment cores in deep areas of the Mediterranean Sea are shown. {yields} {sup 210}Pb{sub xs} and {sup 137}Cs vertical profiles are analysed. {yields} New data on {sup 210}Pb and {sup 137}Cs inventories of Mediterranean deep sediments are

  4. Center for Contaminated Sediments

    Data.gov (United States)

    Federal Laboratory Consortium — The U.S. Army Corps of Engineers Center for Contaminated Sediments serves as a clearinghouse for technology and expertise concerned with contaminated sediments. The...

  5. Superfund: Contaminated Sediments

    Science.gov (United States)

    Contaminated sediments are a significant environmental problem and contribute to the over 3,200 fish consumption advisories nationwide. The Superfund program cleans up sediment sites that present an unacceptable risk to human health or the environment.

  6. Indicators: Sediment Enzymes

    Science.gov (United States)

    Sediment enzymes are proteins that are produced by microorganisms living in the sediment or soil. They are indicators of key ecosystem processes and can help determine which nutrients are affecting the biological community of a waterbody.

  7. Ocean Sediment Thickness Contours

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Ocean sediment thickness contours in 200 meter intervals for water depths ranging from 0 - 18,000 meters. These contours were derived from a global sediment...

  8. National Geochemical Database: Sediment

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Geochemical analysis of sediment samples from the National Geochemical Database. Primarily inorganic elemental concentrations, most samples are of stream sediment in...

  9. Laboratory for Atmospheres 2008 Technical Highlights

    Science.gov (United States)

    Cote, Charles E.

    2009-01-01

    The 2008 Technical Highlights describes the efforts of all members of the Laboratory for Atmospheres. Their dedication to advancing Earth Science through conducting research, developing and running models, designing instruments, managing projects, running field campaigns, and numerous other activities, is highlighted in this report. The Laboratory for Atmospheres (Code 613) is part of the Earth Sciences Division (Code 610), formerly the Earth Sun Exploration Division, under the Sciences and Exploration Directorate (Code 600) based at NASA s Goddard Space Flight Center in Greenbelt, Maryland. In line with NASA s Exploration Initiative, the Laboratory executes a comprehensive research and technology development program dedicated to advancing knowledge and understanding of the atmospheres of Earth and other planets. The research program is aimed at understanding the influence of solar variability on the Earth s climate; predicting the weather and climate of Earth; understanding the structure, dynamics, and radiative properties of precipitation, clouds, and aerosols; understanding atmospheric chemistry, especially the role of natural and anthropogenic trace species on the ozone balance in the stratosphere and the troposphere; and advancing our understanding of physical properties of Earth s atmosphere. The research program identifies problems and requirements for atmospheric observations via satellite missions. Laboratory scientists conceive, design, develop, and implement ultraviolet, infrared, optical, radar, laser, and lidar technology for remote sensing of the atmosphere. Laboratory members conduct field measurements for satellite data calibration and validation, and carry out numerous modeling activities. These modeling activities include climate model simulations, modeling the chemistry and transport of trace species on regional-to-global scales, cloud-resolving models, and development of next-generation Earth system models. Interdisciplinary research is carried

  10. Mars geologic mapping program: Review and highlights

    Science.gov (United States)

    Scott, David H.

    1991-06-01

    The Mars Geologic Mapping (MGM) Program was introduced by NASA in 1987 as a new initiative in the Planetary Geology and Geophysics (PGG) Program. The overall purpose of the program is to support research on topical science problems that address specific questions. Among the objectives of the project are: (1) to produce highly detailed geologic maps that will greatly increase the knowledge of the materials and processes that have contributed to the evolutionary history of Mars; (2) to define areas of special interest for possible future investigation by planned missions (Mars Observer, Mars Sample Return); and (3) to maintain the interest of the planetary community in the development of new concepts and the re-evaluation of Martian geology as new data in usable form become available. Some interesting highlights of the geologic mapping indicate that multiple flood episodes occurred at different times during the Hesperian Period in both Kasei and Maja Valles. Studies of small channels in the Memnonia, Mangala, and Tharsis regions show that fluvial events appear to have occurred during the Amazonian Period at equatorial latitudes. Flood waters occurred during the Amazonian Period at equatorial latitudes. Flood waters from Mangala Valles may have seeped into surficial materials with the subsequent development of numerous sapping channels and debris flows; this suggests that the ancient highland terrain consists of relatively unconsolidated materials. Multiple layers were observed for the first time in the ridged plains lava flows covering large areas of Lunae Planum; some wrinkle ridges in this area are associated with grabens and collapse volcanic units at Hadriaca and Tyrrhena Paterae indicates that the units may have been emplaced by gravity-driven pyroclastic flows. Unlike the north polar layered deposits, those in the south polar region show no angular unconformities or evidence of faulting and folding. Water ice in the south polar layered deposits may be protected

  11. ESR (Erythrocyte Sedimentation Rate) Test

    Science.gov (United States)

    ... products and services. Advertising & Sponsorship: Policy | Opportunities Erythrocyte Sedimentation Rate (ESR) Share this page: Was this page helpful? Also known as: Sed Rate; Sedimentation Rate; Westergren Sedimentation Rate Formal name: Erythrocyte Sedimentation ...

  12. Reservoir Sedimentation and Upstream Sediment Sources: Perspectives and Future Research Needs on Streambank and Gully Erosion.

    Science.gov (United States)

    Fox, G A; Sheshukov, A; Cruse, R; Kolar, R L; Guertault, L; Gesch, K R; Dutnell, R C

    2016-05-01

    The future reliance on water supply and flood control reservoirs across the globe will continue to expand, especially under a variable climate. As the inventory of new potential dam sites is shrinking, construction of additional reservoirs is less likely compared to simultaneous flow and sediment management in existing reservoirs. One aspect of this sediment management is related to the control of upstream sediment sources. However, key research questions remain regarding upstream sediment loading rates. Highlighted in this article are research needs relative to measuring and predicting sediment transport rates and loading due to streambank and gully erosion within a watershed. For example, additional instream sediment transport and reservoir sedimentation rate measurements are needed across a range of watershed conditions, reservoir sizes, and geographical locations. More research is needed to understand the intricate linkage between upland practices and instream response. A need still exists to clarify the benefit of restoration or stabilization of a small reach within a channel system or maturing gully on total watershed sediment load. We need to better understand the intricate interactions between hydrological and erosion processes to improve prediction, location, and timing of streambank erosion and failure and gully formation. Also, improved process-based measurement and prediction techniques are needed that balance data requirements regarding cohesive soil erodibility and stability as compared to simpler topographic indices for gullies or stream classification systems. Such techniques will allow the research community to address the benefit of various conservation and/or stabilization practices at targeted locations within watersheds.

  13. Electrodialytic remediation of sediments

    DEFF Research Database (Denmark)

    Jensen, Pernille Erland

    often hinders this usage. Hence, for both types of sediments, expensive deposition at hazardous waste landfills is required. Electrodialysis is presently being developed as an alternative method for treatment of such contaminated sediments. Heavy metals are removed by treating the sediments...

  14. Cassini's Grand Finale and Recent Science Highlights

    Science.gov (United States)

    Spilker, Linda J.

    2017-06-01

    After almost 13 years in Saturn orbit, the Cassini-Huygens mission has entered its final year of data collection. Cassini will return its final bits of unique data on 15 September 2017 as it plunges into Saturn’s atmosphere, vaporizing and satisfying planetary protection requirements.Since early 2016 Cassini’s orbital inclination was slowly increased towards its final inclination. In November Cassini transitioned to a series of 20 orbits with periapses just outside Saturn's F ring that included some of the closest flybys of the tiny ring moons and excellent views of the F ring and outer A ring.Cassini's final close flyby of Titan in April 2017 propelled it across Saturn’s main rings and into its final orbits. Cassini's Grand Finale began in April 2017 and is comprised of 22 orbits at an inclination of 63 degrees. Cassini is repeatedly diving between the innermost ring and Saturn's upper atmosphere providing insights into fundamental questions unattainable during the rest of the mission. It is the first spacecraft to explore this region.These close orbits provide the highest resolution observations of both the rings and Saturn, and direct in situ sampling of the ring particles' composition, plasma, Saturn's exosphere and the innermost radiation belts. Saturn's gravitational field will be measured to unprecedented accuracy, providing information on Saturn's interior structure and mass distribution in the rings. Probing the magnetic field will give insight into the nature of the magnetic dynamo and the true rotation rate of Saturn's interior. The ion and neutral mass spectrometer will sniff the exosphere and upper atmosphere and examine water-based molecules originating from the rings. The cosmic dust analyzer will sample particle composition from different parts of the main rings.Recent science highlights and science objectives from Cassini’s final orbits will be discussed.This work was carried out in part at the Jet Propulsion Laboratory, California

  15. A {approx}180,000 years sedimentation history of a perialpine overdeepened glacial trough (Wehntal, N-Switzerland)

    Energy Technology Data Exchange (ETDEWEB)

    Anselmetti, F. S. [Eawag, Swiss Federal Institute of Aquatic Science and Technology, Duebendorf (Switzerland); Drescher-Schneider, R. [Institut fuer Pflanzenwissenschaften, Karl-Fanzen-Universitaet Graz, Graz (Austria); Furrer, H. [Palaeontologisches Institut und Museum, Universitaet Zuerich, Zuerich (Switzerland); Graf, H. R. [Matousek, Baumann und Niggli AG, Baden (Switzerland); Lowick, S. E.; Preusser, F. [Institut fuer Geologie, Universitaet Bern, Bern (Switzerland); Riedi, M. A. [Marc A. Riedi, Susenbuehlstrasse 41, Chur (Switzerland)

    2010-11-15

    A 30 m-deep drill core from a glacially overdeepened trough in Northern Switzerland recovered a {approx} 180 ka old sedimentary succession that provides new insights into the timing and nature of erosion-sedimentation processes in the Swiss lowlands. The luminescence-dated stratigraphic succession starts at the bottom of the core with laminated carbonate-rich lake sediments reflecting deposition in a proglacial lake between {approx} 180 and 130 ka ago (Marine Isotope Stage MIS 6). Anomalies in geotechnical properties and the occurrence of deformation structures suggest temporary ice contact around 140 ka. Up-core, organic content increases in the lake deposits indicating a warming of climate. These sediments are overlain by a peat deposit characterised by pollen assemblages typical of the late Eemian (MIS 5e). An abrupt transition following this interglacial encompasses a likely hiatus and probably marks a sudden lowering of the water level. The peat unit is overlain by deposits of a cold unproductive lake dated to late MIS 5 and MIS 4, which do not show any direct influence from glaciers. An upper peat unit, the so-called {sup M}ammoth peat{sup ,} previously encountered in construction pits, interrupts this cold lacustrine phase and marks more temperate climatic conditions between 60 and 45 ka (MIS 3). In the upper part of the core, a succession of fluvial and alluvial deposits documents the Late Glacial and Holocene sedimentation in the basin. The sedimentary succession at Wehntal confirms that the glaciation during MIS 6 did not apparently cause the overdeepening of the valley, as the lacustrine basin fill covering most of MIS 6 is still preserved. Consequently, erosion of the basin is most likely linked to an older glaciation. This study shows that new dating techniques combined with paleoenvironmental interpretations of sediments from such overdeepened troughs provide valuable insights into the past glacial history. (authors)

  16. Highlights from Johannesburg, Gauteng Province, South Africa

    Science.gov (United States)

    2002-01-01

    Although the extraction of mineral wealth has been the major influence in the history of Johannesburg and the surrounding Witwatersrand regions (with about 45% of all gold ever mined coming from there), the discovery of now-famous hominid fossils at the Sterkfontein Caves, and the convening of the world's largest-ever conference on environment and development, are setting a new stage for the future. The United Nations began the second Development and Environment Conference in Johannesburg on August 26, 2002. This meeting addresses the implementation of international goals to fight poverty and protect the global environment that were established at the first such conference held in Rio de Janeiro in 1992. The Johannesburg summit involves about forty thousand participants, and perhaps 100 world leaders. One of several official opening ceremonies for the conference was held at the Sterkfontein Caves to recognize the outstanding universal value of the paleo-anthropological fossils found there.These views from the Multi-angle Imaging SpectroRadiometer (MISR) highlight a number of the land use, vegetation, and geological features found within Gauteng Province (including the urban center of Johannesburg and the capital city Pretoria) and parts of the North West and Free State Provinces. The image on the right displays vegetation in red hues and is a false-color view utilizing data from MISR's near-infrared, red and blue bands. Both the natural-color view (left) and the false-color version were acquired by MISR's nadir camera on June 16, 2002. The urban areas appear as gray-colored pixels in the natural-color view, and exhibit colors corresponding with the relative abundance of vegetation found in the urban parts of this arid region.The mountains trending east-west near the center of the images extend from Pretoria in the east to Rustenberg in the west. These ranges, the Magaliesberg and Witwatersberg, separate the low-lying, hotter bushveld to the north from the cooler

  17. Electric transport in the Netherlands. Highlights 2012; Elektrisch vervoer in Nederland. Highlights 2012

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-03-15

    Businesses, social and educational institutions and governmental institutes work together to accelerate electric transport and to discover and exploit economic opportunities. In 2012, many activities were carried out and results achieved, of which the highlights are presented in this brochure [Dutch] Bedrijfsleven, maatschappelijke- en kennisinstellingen en overheden werken samen aan versnelling van elektrisch vervoer en het ontdekken en benutten van economische kansen. In 2012 werden veel activiteiten uitgevoerd en resultaten geboekt, waarvan in deze brochure verslag wordt gedaan.

  18. Hydraulics characteristics of tipping sediment flushing gate.

    Science.gov (United States)

    Bong, C H J; Lau, T L; Ab Ghani, A

    2013-01-01

    This paper highlights a preliminary study on the potential of a tipping flush gate to be used in an open storm drain to remove sediment. The investigation was carried out by using a plasboard model of the tipping flush gate installed in a rectangular flume. A steady flow experiment was carried out to determine the discharge coefficients and also the outflow relationship of the tipping flush gate. The velocity produced by the gate at various distances downstream of the gate during flushing operation was measured using a flowmeter and the velocity at all the points was higher than the recommended self-cleansing design available in the literature. A preliminary experiment on the efficiency of flushing was conducted using uniform sediment with d50 sizes of 0.81, 1.53 and 4.78 mm. Results generally showed that the number of flushes required to totally remove the sediment from the initial position by a distance of 1 m increased by an average of 1.50 times as the sediment deposit bed thickness doubled. An equation relating the number of flushes required to totally remove the sediment bed for 1 m with the sediment bed deposit thickness was also developed for the current study.

  19. Prediction of bedload sediment transport for heterogeneous sediments in shape

    Science.gov (United States)

    Durafour, Marine; Jarno, Armelle; Le Bot, Sophie; Lafite, Robert; Marin, François

    2015-04-01

    Key words: Particle shape, in-situ measurements, bedload transport, heterogeneous sediments Bedload sediment transport in the coastal area is a dynamic process mainly influenced by the type of hydrodynamic forcings involved (current and/or waves), the flow properties (velocity, viscosity, depth) and sediment heterogeneity (particle size, density, shape). Although particle shape is recognized to be a significant factor in the hydrodynamic behavior of grains, this parameter is not currently implemented in bedload transport formulations: firstly because the mechanisms of initiation of motion according to particle shape are still not fully understood, and secondly due to the difficulties in defining common shape parameters. In March 2011, a large panel of in-situ instruments was deployed on two sites in the Eastern English Channel, during the sea campaign MESFLUX11. Samples of the sediment cover available for transport are collected, during a slack period, per 2cm thick strata by divers and by using a Shipeck grab. Bedload discharges along a tidal cycle are also collected with a Delft Nile Sampler (DNS; Gaweesh and Van Rijn, 1992, 1994) on both sites. The first one is characterized by a sandy bed with a low size dispersion, while the other study area implies graded sediments from fine sands to granules. A detailed analysis of the data is performed to follow the evolution of in-situ bedload fluxes on the seabed for a single current. In-situ measurements are compared to existing formulations according to a single fraction approach, using the median diameter of the mixture, and a fractionwise approach, involving a discretization of the grading curve. Results emphasize the interest to oscillate between these two methods according to the dispersion in size of the site considered. The need to apply a hiding/exposure coefficient (Egiazaroff, 1965) and a hindrance factor (Kleinhans and Van Rijn, 2002) for size heterogeneous sediments is also clearly highlighted. A really good

  20. Towards a Moon Village : Community Workshops Highlights

    Science.gov (United States)

    Foing, Bernard H.

    2016-07-01

    . References: [1] http://sci.esa.int/ilewg/ and https://ildwg.wordpress.com/ [2] Foing B. Moon exploration highlights and Moon Village introduction. [3] Young Lunar Explorers Report ESTEC Moon village sessions with community and young professionals.

  1. A manual to identify sources of fluvial sediment

    Science.gov (United States)

    Gellis, Allen C.; Fitzpatrick, Faith A.; Schubauer-Berigan, Joseph

    2016-01-01

    Sediment is an important pollutant of concern that can degrade and alter aquatic habitat. A sediment budget is an accounting of the sources, storage, and export of sediment over a defined spatial and temporal scale. This manual focuses on field approaches to estimate a sediment budget. We also highlight the sediment fingerprinting approach to attribute sediment to different watershed sources. Determining the sources and sinks of sediment is important in developing strategies to reduce sediment loads to water bodies impaired by sediment. Therefore, this manual can be used when developing a sediment TMDL requiring identification of sediment sources.The manual takes the user through the seven necessary steps to construct a sediment budget:Decision-making for watershed scale and time period of interestFamiliarization with the watershed by conducting a literature review, compiling background information and maps relevant to study questions, conducting a reconnaissance of the watershedDeveloping partnerships with landowners and jurisdictionsCharacterization of watershed geomorphic settingDevelopment of a sediment budget designData collectionInterpretation and construction of the sediment budgetGenerating products (maps, reports, and presentations) to communicate findings.Sediment budget construction begins with examining the question(s) being asked and whether a sediment budget is necessary to answer these question(s). If undertaking a sediment budget analysis is a viable option, the next step is to define the spatial scale of the watershed and the time scale needed to answer the question(s). Of course, we understand that monetary constraints play a big role in any decision.Early in the sediment budget development process, we suggest getting to know your watershed by conducting a reconnaissance and meeting with local stakeholders. The reconnaissance aids in understanding the geomorphic setting of the watershed and potential sources of sediment. Identifying the potential

  2. GPR-derived architecture of jökulhlaup sediments, Gígjökull, Iceland

    Science.gov (United States)

    Harrison, Devin; Ross, Neil; Russell, Andrew; Dunning, Stuart

    2017-04-01

    A warming global climate has implications for glacial retreat and meltwater generation. In Iceland, the potential frequency and magnitude of jökulhlaup (glacial outburst flood) hazards from ice-dammed and moraine-dammed lakes may be increased by: (i) increased glacial meltwater production; and (ii) the glacio-isostatic response of the mantle driven by deglaciation, which is hypothesised to increase volcanic activity. The high peak-discharges of volcanically-induced jökulhlaups in Iceland have the ability to deposit significant volumes of sediment, causing major geomorphic change and societal impacts. Understanding geomorphological process associated with jökulhlaups can assist in predicting and evaluating future jökulhlaup behaviour and impacts. The 2010 Eyjafjallajökull eruption produced multiple jökulhlaups resulting in major sediment deposition and proglacial aggradation. Observations of the timing, scale and hydraulic properties of these jökulhlaups during the eruption have provided a unique opportunity to investigate the impact of ice-rich meltwater flows on the proglacial environment. Using low-frequency (40 MHz) ground penetrating radar (GPR) and differential GPS (dGPS) surveys of the Gígjökull basin, this study has: (1) geophysically characterised the thick sequence of sedimentary deposits associated with the Eyjafjallajökull eruption, to test conceptual models of jökulhlaup deposition; and (2) quantified post-depositional (2010-2016) elevation change, to evaluate the role of buried ice on post-jökulhlaup landscape response and recovery. The jökulhlaup deposits are characterised by three prominent sediment sub-units, delimited by strong continuous reflectors, and displaying discontinuous undulating reflections (indicating the presence of dunes or anti-dunes). The structures within these sub-units provide insight into the fluvial processes associated with multiple high-magnitude flood events and their relation to the hydraulic properties and

  3. Sediment Core Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Provides instrumentation and expertise for physical and geoacoustic characterization of marine sediments.DESCRIPTION: The multisensor core logger measures...

  4. Dynamics of Cohesive Sediments

    DEFF Research Database (Denmark)

    Johansen, Claus

    The present thesis considers the transport processes of cohesive sediments. The cohesive sediment used in the laboratory experiments was kaolinite, a clay mineral, in order to be able to reproduce the individual experiments. In the first part of the thesis, the theoretical considerations regarding...... the nature of the cohesive sediment with respect to the transport processes is presented. In addition, the flocculation process and the rheological behaviour of cohesive sediments is outlined. The second part contains the laboratory experiments. The laboratory experiments were conducted with respect...

  5. Sediment supply to beaches

    DEFF Research Database (Denmark)

    Aagaard, Troels

    2014-01-01

    Many beaches have been built by an onshore supply of sand from the shoreface, and future long-term coastal evolution critically depends on cross-shore sediment exchange between the upper and the lower shorefaces. Even so, cross-shore sediment supply remains poorly known in quantitative terms...... and this reduces confidence in predictions of long-term shoreline change. In this paper, field measurements of suspended sediment load and cross-shore transport on the lower shoreface are used to derive a model for sediment supply from the lower to the upper shoreface at large spatial and temporal scales. Data...

  6. Three decades of monitoring in the Rio Cordon instrumented basin: Sediment budget and temporal trend of sediment yield

    Science.gov (United States)

    Rainato, R.; Mao, L.; García-Rama, A.; Picco, L.; Cesca, M.; Vianello, A.; Preciso, E.; Scussel, G. R.; Lenzi, M. A.

    2017-08-01

    This paper investigates nearly 30 years of monitoring of sediment fluxes in an instrumented Alpine basin (Rio Cordon, Italy). The collected bedload and suspended sediment transport data allows sediment dynamics to be analyzed at different time scales, ranging from short- (single event) to long-term (three decades). The Rio Cordon monitoring station has been operating since 1986, continuously recording water discharge, bedload and suspended load. At the flood event scale, a good relationship was found between peak discharges (Qpeak) and sediment load (bedload and suspended load). The inter-annual sediment yields were analyzed, also assessing the contribution of the single floods to the total sediment budget. The annual suspended load ranges from 10 to 2524 t yr- 1, while the bedload varies from 0 to 1543 t yr- 1. The higher annual yields were recorded in the years when large floods occurred, highlighting that the sediment budget in the Rio Cordon is strongly controlled by the occurrence of high magnitude events. Investigation of the seasonal suspended load contribution demonstrated that from 1986 to 1993 most fine sediments were transported during the snowmelt/summer seasons, while autumn and snowmelt were the dominant seasons contributing to sediment yield in the periods 1994-2002 and 2003-2014, respectively. The mean annual sediment yield from 1986 to 2014 is equal to 103 t km- 2 yr- 1, and overall, bedload accounts for 21% of the total sediment yield. The ratio between the sediment transport and the effective runoff of the events allowed the temporal trends of transport efficiency to be inferred, highlighting the existence of periods characterized by different sediment availability. In particular, despite no significant changes in the hydrological variables (i.e. rainfall), nearly a decade (1994-2002) with high transport efficiency appears to have occurred after an exceptional event (recurrence interval > 100 years). This event affected the sediment availability

  7. A script to highlight hydrophobicity and charge on protein surfaces

    Directory of Open Access Journals (Sweden)

    Dominique eHagemans

    2015-10-01

    Full Text Available The composition of protein surfaces determines both affinity and specificity of protein-protein interactions. Matching of hydrophobic contacts and charged groups on both sites of the interface are crucial to ensure specificity. Here, we propose a highlighting scheme, YRB, which highlights both hydrophobicity and charges in protein structures. YRB highlighting visualises hydrophobicity by highlighting all carbon atoms that are not bound to nitrogen and oxygen atoms. The charged oxygens of glutamate and aspartate are highlighted red and the charged nitrogens of arginine and lysine are highlighted blue. For a set of representative examples, we demonstrate that YRB highlighting intuitively visualises segments on protein surfaces that contribute to specificity in protein-protein interfaces, including Hsp90/co-chaperone complexes, SNARE complex and a transmembrane domain. We provide YRB highlighting in form of a script that runs using the software PyMOL.

  8. Analytical Ultracentrifugation: Sedimentation Velocity and Sedimentation Equilibrium

    Science.gov (United States)

    Cole, James L.; Lary, Jeffrey W.; Moody, Thomas; Laue, Thomas M.

    2009-01-01

    Analytical ultracentrifugation (AUC) is a versatile and powerful method for the quantitative analysis of macromolecules in solution. AUC has broad applications for the study of biomacromolecules in a wide range of solvents and over a wide range of solute concentrations. Three optical systems are available for the analytical ultracentrifuge (absorbance, interference and fluorescence) that permit precise and selective observation of sedimentation in real time. In particular, the fluorescence system provides a new way to extend the scope of AUC to probe the behavior of biological molecules in complex mixtures and at high solute concentrations. In sedimentation velocity, the movement of solutes in high centrifugal fields is interpreted using hydrodynamic theory to define the size, shape and interactions of macromolecules. Sedimentation equilibrium is a thermodynamic method where equilibrium concentration gradients at lower centrifugal fields are analyzed to define molecule mass, assembly stoichiometry, association constants and solution nonideality. Using specialized sample cells and modern analysis software, researchers can use sedimentation velocity to determine the homogeneity of a sample and define whether it undergoes concentration-dependent association reactions. Subsequently, more thorough model-dependent analysis of velocity and equilibrium experiments can provide a detailed picture of the nature of the species present in solution and their interactions. PMID:17964931

  9. Testing lagoonal sediments with early life stages of the copepod Acartia tonsa (Dana): An approach to assess sediment toxicity in the Venice Lagoon

    DEFF Research Database (Denmark)

    Picone, Marco; Bergamin, Martina; Delaney, Eugenia

    2018-01-01

    with sea urchin and bivalves embryos. Sediment toxicity data highlighted the high sensitivity and the clear ability of the larval development to discriminate among sediments characterized by different levels of contamination. The data of the definitive study evidenced that inhibition of the larval...

  10. Coral morphology and sedimentation.

    Science.gov (United States)

    Duckworth, Alan; Giofre, Natalie; Jones, Ross

    2017-08-29

    The sediment rejection ability of 8 coral species of 5 families and 3 morphologies were assessed in a series of short term exposure tests over a sedimentation range of 0.5-40mgcm(-2)d(-1) and one longer term exposure test of 235mgcm(-2). Sediment accumulation rates on live corals and dead (enamel-covered) skeletons varied between morphologies, with branching species often more adept at self-cleaning. Flow rates (0-17cms(-1)) significantly affected sediment-shedding ability as did differences in particle sizes, with coarse silt rejected faster than fine silt, but only at very high (235mgcm(-2)) deposition rates. Siliciclastic sediment was rejected faster than carbonate sediments and smothering for many days by mms of low organic content carbonate sediment resulted in bleaching, but no mortality. The findings are discussed with respect to turbidity generated in natural and dredging-related resuspension events and in the context for impact prediction for dredging projects. Copyright © 2017. Published by Elsevier Ltd.

  11. Thermal structure of proglacial lakes in Patagonia

    National Research Council Canada - National Science Library

    Sugiyama, Shin; Minowa, Masahiro; Sakakibara, Daiki; Skvarca, Pedro; Sawagaki, Takanobu; Ohashi, Yoshihiko; Naito, Nozomu; Chikita, Kazuhisa

    2016-01-01

    .... To better understand ice‐water interactions at the front of freshwater calving glaciers, we measured lakewater temperature, turbidity, and bathymetry near Glaciar Perito Moreno, Upsala, and Viedma, large calving glaciers...

  12. Inertial Screening in Sedimentation

    OpenAIRE

    Segre, P. N.

    2007-01-01

    We use particle image velocimetry to measure the sedimentation dynamics of a semi-dilute suspension of non-Brownian spheres at Reynolds numbers, $0.001\\le Re\\le 2.3$, extending from the Stokes to the moderately inertial regime. We find that the onset of inertial corrections to Stokes sedimentation occurs when the inertial screening length $l=a/Re$ becomes similar to the Stokes sedimentation length $\\xi_0$, at $Re_c= a/\\xi_0\\approx 0.05$. For $Re>Re_c$, inertial screening significantly reduces...

  13. The contribution of bank and surface sediments to fluvial sediment ...

    African Journals Online (AJOL)

    Sediment source studies involving a simple mixing model was undertaken in the Pra River Basin in Ghana using a single tracer 210Pb to determine the relative contribution of surface and bank sediments to the fluvial sediment transport. Sediment source tracing was performed on the basis of sub-basins by comparing the ...

  14. A ~20,000 year history of glacial variability in the tropical Andes recorded in lake sediments from the Cordillera Blanca, Peru

    Science.gov (United States)

    Stansell, N.; Rodbell, D. T.; Moy, C. M.

    2010-12-01

    Pro-glacial lake sediments from the Cordillera Blanca, Peru contain continuous records of climate variability spanning the Last Glacial Maximum to present day. Here we present results from two alpine lake basins in the Queshgue Valley (9.8°S, 77.3°W) that contain high-resolution records of clastic sediment deposition for the last ~20,000 years. Radiocarbon-dated sediment cores were scanned at 0.5 to 1.0 cm resolution using a profiling x-ray fluorescence scanner for major and minor element distributions. In addition, we measured down-core variations in magnetic susceptibility, organic carbon, biogenic silica and calcium carbonate. Samples of bedrock and sediments from glacial moraines in the Queshgue watershed were analyzed using an ICP-MS in order to fingerprint and trace the source of glacial sediments deposited in the lakes. The bedrock is dominated by a combination of granodiorite with high Sr concentrations and meta-sedimentary rocks with high Zr values. Because the glacial sediments proximal to the modern glacier terminus are composed mostly of the granodiorite end-member, we interpret changes in Sr and clastic sediment concentrations in the lake sediment profiles as proxies for past glacial variability. Preliminary results indicate that glaciers retreated soon after ~14,500 cal yr BP and remained less extensive during the remaining late Glacial Stage and early Holocene. Gradually increasing clastic sediments through the middle and late Holocene indicate that glaciers became progressively larger, or more erosive towards present day. However, this overall Holocene trend of increasing glacier extent was interrupted by multiple periods of centennial- to millennial-scale ice margin retreat. For example, relative peaks in clastic sediments occurred from ~14,500 to 6000, 5600 to 5000, 4600 to 4200, 3600 to 3200, 2800 to 2700, 2400 to 2200, 1750 to 1550, 1100 to 900 cal yr BP, and during the Little Ice Age (~700 to 50 cal yr BP), while periods of low clastic

  15. Highlight detection for video content analysis through double filters

    Science.gov (United States)

    Sun, Zhonghua; Chen, Hexin; Chen, Mianshu

    2005-07-01

    Highlight detection is a form of video summarization techniques aiming at including the most expressive or attracting parts in the video. Most video highlights selection research work has been performed on sports video, detecting certain objects or events such as goals in soccer video, touch down in football and others. In this paper, we present a highlight detection method for film video. Highlight section in a film video is not like that in sports video that usually has certain objects or events. The methods to determine a highlight part in a film video can exhibit as three aspects: (a) locating obvious audio event, (b) detecting expressive visual content around the obvious audio location, (c) selecting the preferred portion of the extracted audio-visual highlight segments. We define a double filters model to detect the potential highlights in video. First obvious audio location is determined through filtering the obvious audio features, and then we perform the potential visual salience detection around the potential audio highlight location. Finally the production from the audio-visual double filters is compared with a preference threshold to determine the final highlights. The user study results indicate that the double filters detection approach is an effective method for highlight detection for video content analysis.

  16. Sediment Temperature, 2015

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data table contains summary data for temperature time series in near-surface sediments in high and low tidal marsh at 7 sites during 2015. These data support...

  17. Sediment Resuspension Data

    Data.gov (United States)

    U.S. Environmental Protection Agency — The full report on sediment resuspension in drinking water storage tanks and a link to an animation of results. This dataset is associated with the following...

  18. Offshore Surficial Sediment

    Data.gov (United States)

    California Department of Resources — This data layer (PAC_EXT.txt and PAC_PRS.txt) represents two of five point coverages of known sediment samples, inspections, and probes from the usSEABED data...

  19. Analytical Ultracentrifugation: Sedimentation Velocity and Sedimentation Equilibrium

    OpenAIRE

    Cole, James L.; Lary, Jeffrey W.; Moody, Thomas; Thomas M Laue

    2008-01-01

    Analytical ultracentrifugation (AUC) is a versatile and powerful method for the quantitative analysis of macromolecules in solution. AUC has broad applications for the study of biomacromolecules in a wide range of solvents and over a wide range of solute concentrations. Three optical systems are available for the analytical ultracentrifuge (absorbance, interference and fluorescence) that permit precise and selective observation of sedimentation in real time. In particular, the fluorescence sy...

  20. Site-specific features influence sediment stability of intertidal flats

    Science.gov (United States)

    Defew, Emma C.; Tolhurst, Trevor J.; Paterson, David M.

    The factors that influence the sediment stability and the transport of estuarine mudflats are not yet fully understood but knowledge of them is essential in coastal engineering applications and pollution ecology studies. The suggestion that variation in predictive models of sediment stability might be due to site-specific characteristics is investigated using data from four estuarine mudflats (Eden Estuary, Scotland, the Biezelingsche Ham, Zandkreek, and Molenplaat mudflats in The Netherlands). These estuaries differ in their environmental conditions, macrofaunal species composition and local features (e.g. Enteromorpha mats, migratory biofilms). Stable and unstable sediments were compared, and mean chlorophyll-a concentrations and granulometry of the sediments were significantly different between the two groups. Step-wise multiple linear regressions were applied to the sediment stability data of all sites to establish the influences on erosion threshold of microphytobenthic biomass, water content, granulometry, organic carbon content and the abundance of dominant macrofaunal species. The stability of each site was influenced by different factors. Sediment stability of the Eden Estuary was affected by the Enteromorpha bloom; Biezelingsche Ham was influenced by the highly migratory nature of the diatom biofilms and the abundance of Corophium volutator; the polychaete worm Arenicola marina had a net negative effect on sediment stability of the Zandkreek; and the Molenplaat was influenced by microphytobenthic biomass. This research highlights the need for site-specific calibration of models and suggests that a universal proxy parameter for sediment stability is unlikely to be obtained.

  1. Towards Visual Sedimentation

    OpenAIRE

    Huron, Samuel; Vuillemot, Romain; Fekete, Jean-Daniel

    2012-01-01

    This Poster receive the Best Poster award from the IEEE INFOVIS committee.; International audience; We present Visual Sedimentation, a new design metaphor for visualizing streaming data inspired by the geological process of sedimentation. Our work started by early experiments visualiz- ing political Twitter streams during the French 2012 presidential elections, and social interactions during a TV show. In both cases, the positive feedback we received expressed an unexpectedly high level of en...

  2. Underwater Sediment Sampling Research

    Science.gov (United States)

    2017-01-01

    aggressive mixing imparted energy to the oil /sediment/water mixtures, and essentially set up a multi- phase system that was not in physio-chemical...This is necessary because variation in ROV design leaves many essential details unknown (e.g., electromechanical control cable vs. optical control...volatility, etc.). The aggressive mixing imparted energy to the oil /sediment/water mixtures, and essentially set up a multi- phase system that was

  3. Community Sediment Transport Model

    Science.gov (United States)

    2007-01-01

    with IKONOS imagery). The tidal-residual circulation (arrows, right panel) in the CSTM simulations generates sediment transport consistent with...method for estimating surface sediment concentrations from AVHRR using the method described in Myint and Walker (2002). Water quality parameters for...frequencies. A model with a spectral wave driver has a better convergence rate than a monochromatic wave driver. Optimized coupling frequencies are

  4. Brookhaven highlights, October 1, 1989--September 30, 1990

    Energy Technology Data Exchange (ETDEWEB)

    Rowe, M.S.; Cohen, A.; Greenberg, D.; Seubert, L.; Kuper, J.B.H. (eds.)

    1990-01-01

    This report discusses research being conducted at Brookhaven National Laboratory. Highlights from all the department are illustrated. The main topics are on accelerator development and applications. (LSP)

  5. Contemporary suspended sediment dynamics within two partly glacierized mountain drainage basins in western Norway (Erdalen and Bødalen, inner Nordfjord)

    Science.gov (United States)

    Beylich, Achim A.; Laute, Katja; Storms, Joep E. A.

    2017-06-01

    the drainage basin surface area) as compared to Erdalen (18% of the drainage basin surface area) and by a significantly higher sediment yield from the glacierized area of the Bødalen drainage basin compared to the glacierized surface area in Erdalen. When looking at the total annual mass of suspended sediments being fluvially exported from both entire drainage basin systems, the total amount of suspended sediments coming from the ice-free drainage basin surface areas altogether dominates over the total amount of suspended sediments coming from the glacierized surface area of both drainage basins. Drainage-basin wide annual suspended sediment yields are rather low when compared with yields of other partly glacierized drainage basin systems in Norway and in other cold climate environments worldwide, which is mainly due to the high resistance of the predominant gneisses towards glacial erosion and weathering, the altogether only small amounts of sediments being available within the entire drainage basin systems, the stable and nearly closed vegetation cover in the ice-free surface areas with sedimentary covers, and the efficiency of proglacial lakes in trapping sediments supplied by defined outlet glaciers. Both contemporary and long-term suspended sediment yields are altogether supply-limited. Contemporary suspended sediment transport accounts for nearly two-thirds of the total fluvial transport and, accordingly, plays an important role within the sedimentary budgets of the entire Erdalen and Bødalen drainage basins.

  6. Analytical Ultracentrifugation of Inorganic Colloids; Sedimentation Velocity of Interacting and Non-Interacting Particles

    NARCIS (Netherlands)

    Planken, K.L.

    2008-01-01

    Several case studies of the sedimentation velocity of non-interacting, attractive and repulsive colloids are discussed. After a brief introduction that highlights historical facts, basic analytical ultracentrifugation theory, some instrument issues and experiments are reviewed. The existence of

  7. Small Drinking Water Systems Communication and Outreach Highlights

    Science.gov (United States)

    As part of our small drinking water systems efforts, this poster highlights several communications and outreach highlights that EPA's Office of Research and Development and Office of Water have been undertaking in collaboration with states and the Association of State Drinking Wa...

  8. Operational considerations for implementing regional sediment management plans in the northern Gulf of Mexico

    Science.gov (United States)

    Underwood, Steven G.; Khalil, Syed M.; Byrnes, Mark R.; Steyer, Gregory D.; Raynie, Richard C

    2015-01-01

    Development of a comprehensive and stakeholder-driven Regional Sediment Management plan can provide the basis for long-term sustainable resource use and protection. This paper highlights three operational components that can positively influence sediment management at a regional scale, including (1) integration of an operational sediment budget, (2) development of a monitoring and adaptive management plan, and (3) development of a regional sediment availability and allocation program. These components seek to incorporate science and adaptive management through implementation of an organized and well-documented decision making process. They represent a coordinated framework that could serve as a guide for unifying financial investments in regional sediment management plans. Collectively, they establish an integrated process for addressing uncertainties about future system change in light of shrinking federal and state budgets, competing demands for sediment resources within riverine and marine waters, and policy considerations related to sediment/water use (e.g., navigation and commerce versus environmental management).

  9. Estimating floodplain sedimentation in the Laguna de Santa Rosa, Sonoma County, CA

    Science.gov (United States)

    Curtis, Jennifer A.; Flint, Lorraine E.; Hupp, Cliff R.

    2013-01-01

    We present a conceptual and analytical framework for predicting the spatial distribution of floodplain sedimentation for the Laguna de Santa Rosa, Sonoma County, CA. We assess the role of the floodplain as a sink for fine-grained sediment and investigate concerns regarding the potential loss of flood storage capacity due to historic sedimentation. We characterized the spatial distribution of sedimentation during a post-flood survey and developed a spatially distributed sediment deposition potential map that highlights zones of floodplain sedimentation. The sediment deposition potential map, built using raster files that describe the spatial distribution of relevant hydrologic and landscape variables, was calibrated using 2 years of measured overbank sedimentation data and verified using longer-term rates determined using dendrochronology. The calibrated floodplain deposition potential relation was used to estimate an average annual floodplain sedimentation rate (3.6 mm/year) for the ~11 km2 floodplain. This study documents the development of a conceptual model of overbank sedimentation, describes a methodology to estimate the potential for various parts of a floodplain complex to accumulate sediment over time, and provides estimates of short and long-term overbank sedimentation rates that can be used for ecosystem management and prioritization of restoration activities.

  10. Heavy metals in surface sediments of the Jialu River, China: Their relations to environmental factors

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Jie [State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210093 (China); Environmental Engineering Program, Department of Civil Engineering, Auburn University, Auburn, AL 36849 (United States); Zhao, Changpo [State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210093 (China); Luo, Yupeng [Department of Mathematics and Statistics, Auburn University, Auburn, AL 36849 (United States); Liu, Chunsheng, E-mail: liuchunshengidid@126.com [College of Fisheries, Huazhong Agricultural University, Wuhan 430070 (China); Kyzas, George Z. [Laboratory of General and Inorganic Chemical Technology, Department of Chemistry, Aristotle University of Thessaloniki, Thessaloniki 54124 (Greece); Luo, Yin [State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210093 (China); Zhao, Dongye [Environmental Engineering Program, Department of Civil Engineering, Auburn University, Auburn, AL 36849 (United States); An, Shuqing [State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210093 (China); Zhu, Hailiang, E-mail: zhuhl@nju.edu.cn [State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210093 (China)

    2014-04-01

    Highlights: • Zhengzhou City had major effect on the pollution of the Jialu River. • TN, OP, TP and COD{sub Mn} in water drove heavy metals to deposit in sediments. • B-IBI was sensitive to the adverse effect of heavy metals in sediments. - Abstract: This work investigated heavy metal pollution in surface sediments of the Jialu River, China. Sediment samples were collected at 19 sites along the river in connection with field surveys and the total concentrations were determined using atomic fluorescence spectrometer and inductively coupled plasma optical emission spectrometer. Sediment samples with higher metal concentrations were collected from the upper reach of the river, while sediments in the middle and lower reaches had relatively lower metal concentrations. Multivariate techniques including Pearson correlation, hierarchical cluster and principal components analysis were used to evaluate the metal sources. The ecological risk associated with the heavy metals in sediments was rated as moderate based on the assessments using methods of consensus-based Sediment Quality Guidelines, Potential Ecological Risk Index and Geo-accumulation Index. The relations between heavy metals and various environmental factors (i.e., chemical properties of sediments, water quality indices and aquatic organism indices) were also studied. Nitrate nitrogen, total nitrogen, and total polycyclic aromatic hydrocarbons concentrations in sediments showed a co-release behavior with heavy metals. Ammonia nitrogen, total nitrogen, orthophosphate, total phosphate and permanganate index in water were found to be related to metal sedimentation. Heavy metals in sediments posed a potential impact on the benthos community.

  11. Influenza-Sediment Interactions

    Science.gov (United States)

    Trusiak, A.; Block, K. A.; Katz, A.; Gottlieb, P.; Alimova, A.; Galarza, J.; Wei, H.; Steiner, J. C.

    2013-12-01

    A typical water fowl can secrete 1012 influenza virions per day. Therefore it is not unexpected that influenza virions interact with sediments in the water column. The influence of sediments on avian influenza virions is not known. With the threat of avian influenza emerging into the human population, it is crucial to understand virus survivability and residence time in a body of water. Influenza and clay sediments are colloidal particles and thus aggregate as explained by DLVO (Derjaguin & Landau, Verwey & Overbeek) theory. Of great importance is an understanding of the types of particulate or macromolecular components that bind the virus particles, and whether the virus remains biologically active. We present results of hetero-aggregation and transmission electron microscopy experiments performed with influenza A/PR8/38. Influenza particles are suspended with sediment and minimal nutrients for several days, after which the components are evaluated to determine influenza concentration and survivability. Transmission electron microscopy results are reported on the influenza-sediment aggregates to elucidate structure and morphology of the components.

  12. Is Domain Highlighting Actually Helpful in Identifying Phishing Web Pages?

    Science.gov (United States)

    Xiong, Aiping; Proctor, Robert W; Yang, Weining; Li, Ninghui

    2017-06-01

    To evaluate the effectiveness of domain highlighting in helping users identify whether Web pages are legitimate or spurious. As a component of the URL, a domain name can be overlooked. Consequently, browsers highlight the domain name to help users identify which Web site they are visiting. Nevertheless, few studies have assessed the effectiveness of domain highlighting, and the only formal study confounded highlighting with instructions to look at the address bar. We conducted two phishing detection experiments. Experiment 1 was run online: Participants judged the legitimacy of Web pages in two phases. In Phase 1, participants were to judge the legitimacy based on any information on the Web page, whereas in Phase 2, they were to focus on the address bar. Whether the domain was highlighted was also varied. Experiment 2 was conducted similarly but with participants in a laboratory setting, which allowed tracking of fixations. Participants differentiated the legitimate and fraudulent Web pages better than chance. There was some benefit of attending to the address bar, but domain highlighting did not provide effective protection against phishing attacks. Analysis of eye-gaze fixation measures was in agreement with the task performance, but heat-map results revealed that participants' visual attention was attracted by the highlighted domains. Failure to detect many fraudulent Web pages even when the domain was highlighted implies that users lacked knowledge of Web page security cues or how to use those cues. Potential applications include development of phishing prevention training incorporating domain highlighting with other methods to help users identify phishing Web pages.

  13. Transition logo detection for sports videos highlight extraction

    Science.gov (United States)

    Su, Po-Chyi; Wang, Yu-Wei; Chen, Chien-Chang

    2006-10-01

    This paper presents a highlight extraction scheme for sports videos. The approach makes use of the transition logos inserted preceding and following the slow motion replays by the broadcaster, which demonstrate highlights of the game. First, the features of a MPEG compressed video are retrieved for subsequent processing. After the shot boundary detection procedure, the processing units are formed and the units with fast moving scenes are then selected. Finally, the detection of overlaying objects is performed to signal the appearance of a transition logo. Experimental results show the feasibility of this promising method for sports videos highlight extraction.

  14. Copper in the sediment

    DEFF Research Database (Denmark)

    Nielsen, Søren Laurentius; Banta, Gary Thomas; Khan, Farhan

    2017-01-01

    route between sediment and water. Measured endpoints were Cu accumulation in root and leaves, relative growth rate, leaf mortality, chlorophyll concentration, and maximum photosynthetic quantum yield. Cu accumulation from the sediment was translocated to all parts of the plant, while Cu taken up from...... the water showed a tendency to remain in leaves. Effects on relative growth rate and leaf mortality were found only following uptake of Cu from the sediment. We tested effects of different salinities, acting as multiple stressors, together with Cu, but found only weak effects with little interaction with Cu......Eelgrass (Zostera marina L.) is an important organism in coastal marine waters and is highly likely to encounter exposure to multiple stressors, both anthropogenic contaminants and natural stressors. Here, we exposed eelgrass to a range of Cu concentrations and salinities, and also varied exposure...

  15. Sediment transport mechanics

    Science.gov (United States)

    Ballio, Francesco; Tait, Simon

    2012-12-01

    The Editor of Acta Geophysica and the Guest Editors wish to dedicate this Topical Issue on Sediment Transport Mechanics to the memory of Stephen Coleman, who died recently. During his career, Stephen had made an outstanding scientific contribution to the topic of Sediment Transport. The level of his contribution is demonstrated in the paper by Aberle, Coleman, and Nikora included in this issue, on which he started working before becoming aware of the illness that led to his untimely death. For scholars and colleagues Stephen remains an example of intellectual honesty and scientific insight.

  16. FY17 Transportation and Hydrogen Systems Center Journal Publication Highlights

    Energy Technology Data Exchange (ETDEWEB)

    2017-12-08

    NREL's Transportation and Hydrogen Systems Center published 39 journal articles in fiscal year 2017 highlighting recent research in advanced vehicle technology, alternative fuels, and hydrogen systems.

  17. EMSL Quarterly Highlights Report: 1st Quarter, Fiscal Year 2009

    Energy Technology Data Exchange (ETDEWEB)

    Showalter, Mary Ann; Kathmann, Loel E.; Manke, Kristin L.

    2009-02-02

    The EMSL Quarterly Highlights Report covers the science, staff and user recognition, and publication activities that occurred during the 1st quarter (October 2008 - December 2008) of Fiscal Year 2009.

  18. Physical and Life Sciences 2008 Science & Technology Highlights

    Energy Technology Data Exchange (ETDEWEB)

    Correll, D L; Hazi, A U

    2009-05-06

    This document highlights the outstanding research and development activities in the Physical and Life Sciences Directorate that made news in 2008. It also summarizes the awards and recognition received by members of the Directorate in 2008.

  19. EMSL Quarterly Highlights Report: FY 2008, 3rd Quarter

    Energy Technology Data Exchange (ETDEWEB)

    Showalter, Mary Ann

    2008-09-16

    The EMSL Quarterly Highlights Report covers the science, staff and user recognition, and publication activities that occurred during the 1st quarter (October 2007 - December 2007) of Fiscal Year 2008.

  20. EMSL Quarterly Highlights Report: 1st Quarter, FY08

    Energy Technology Data Exchange (ETDEWEB)

    Showalter, Mary Ann

    2008-01-28

    The EMSL Quarterly Highlights Report covers the science, staff and user recognition, and publication activities that occurred during the 1st quarter (October 2007 - December 2007) of Fiscal Year 2008.

  1. Cascade dams influence on sediment characteristics and phosphorus distribution.

    Science.gov (United States)

    Rapin, Anne; Mourier, Brice; Rabiet, Marion; Malgorzata, Grybos; Kestens, Tim; Deluchat, Veronique

    2017-04-01

    Massive river artificialisation by dam construction, responding to the steadily increasing human demand of water and electricity leads to several environmental consequences, including alteration of hydrological dynamic and sediment discontinuity. Important decreases of water flows and sediment transport downstream impact phosphorus (P) flux to the ocean and its cycle, due to P sediment storage in dam reservoir. Moreover, the release of P from sediments may enhance eutrophication processes in dam reservoir. Our study focused on the influence of cascade dams on physical and chemical characteristics of sediments and particularly on P sedimentary speciation along river continuum. Considering these results, the potential of P release from dam reservoir sediments was appraised and compared to un-impacted river parts. In addition, key parameters controlling P release at sediment/water interface were evaluated. Champsanglard, Chézelles and Age are three consecutive hydroelectric reservoirs on Creuse River (France; respective surfaces area of 55 ha, 23 ha, 38 ha and approximative height of 20 m each) subjected to seasonal cyanobacterial blooms. Surface sediments (17 samples) were collected in dams and free-flow river sections (on a stretch of 17 km); chemical composition (Fe, Al, Ca, Mn and P), organic matter (OM) content, particle size distribution and P fractionation were analysed. An abrupt change in sediment granulometry from a coarse-medium sand to silt texture going through free-flow river to dam reservoirs was observed. The same assessment was made in regard to OM content (from 3 ± 3% in river parts to 18 ± 3% in dams) and total P (0.27 ± 0.11 mgP/g DW in river parts to 1.8 ± 0.3 mgP/gDW in dams). P enrichment in sediment from dam reservoir is due to the retention of fine size particles. Relation between total P content and sediment grain size within each dam reservoir highlighted the role of slowdown river flow occurring in dams. In Champsanglard reservoir

  2. Reservoir sedimentation research at the National Sedimentation Laboratory

    Science.gov (United States)

    Researchers at the National Sedimentation Laboratory have made important contributions to reservoir sedimentation research for most of the 50 years that the laboratory has existed. Early publications from the mid 1960s to the mid 1970s reported work on the development of gamma ray sediment measurem...

  3. Sediments of a retting yard

    Digital Repository Service at National Institute of Oceanography (India)

    Remani, K.N.; Venugopal, P.; Devi, K.S.; Unnithan, R.V.

    Sediments of a coconut husk retting yard and a reference station in Cochin backwaters, Kerala, India were studied for 1 yr. Effects of monsoon were found significant Organic carbon and organic matter showed enrichment in the retting ground sediments...

  4. Soils and organic sediments

    Energy Technology Data Exchange (ETDEWEB)

    Head, M.J. [University of Wollongong, Wollongong, NSW (Australia). School of Geosciences

    1999-11-01

    The organic component of soils is basically made up of substances of an individual nature (fats, waxes, resins, proteins, tannic substances, and many others), and humic substances (Kononova, 1966). These are complex polymers formed from breakdown products of the chemical and biological degradation of plant and animal residues. They are dark coloured, acidic, predominantly aromatic compounds ranging in molecular weight from less than one thousand to tens of thousands (Schnitzer, 1977). They can be partitioned into three main fractions:(i) Humic acid, which is soluble in dilute alkaline solution, but can be precipitated by acidification of the alkaline extract.(ii) Fulvic acid, which is soluble in alkaline solution, but is also soluble on acidification.(iii) Humin that cannot be extracted from the soil or sediment by dilute acid or alkaline solutions. It has mostly been assumed that the humic and fulvic acid components of the soil are part of the mobile, or `active` component, and the humin component is part of the `passive` component. Other types of organic sediments are likely to contain chemical breakdown products of plant material, plant fragments and material brought in from outside sources. The outside material can be contemporaneous with sediment deposition, can be older material, or younger material incorporated into the sediment long after deposition. Recognition of `foreign` material is essential for dating, but is not an easy task. Examples of separation techniques for humic and non humic components are evaluated for their efficiency 18 refs.

  5. Sulfur diagenesis in marine sediments

    Science.gov (United States)

    Goldhaber, M.

    1985-01-01

    Bacterial sulfate reduction occurs in all marine sediments that contain organic matter. Aqueous sulfide (HS-, H2S), one of the initial products of bacterial sulfide reduction, is extremely reactive with iron bearing minerals: sulfur is fixed into sediments as iron sulfide (first FeS and then Fe2S2). A working definition is given of sulfur diagenesis in marine sediments. Controls and consequences of sulfate reduction rates in marine sediments are examined.

  6. Deconvolving the process-origin of sediments on volcanic mountains and implications for paleoclimatic reconstruction: Mt Ruapehu area, New Zealand

    Science.gov (United States)

    Brook, Martin; Winkler, Stefan

    2016-04-01

    Glaciation on the central North Island of New Zealand is limited to the volcanoes of Tongariro National Park, including Mt Ruapehu, the largest and most active andesitic stratovolcano on the North Island. At 2797 m asl, Mt Ruapehu represents the only peak in the North Island to currently intercept the permanent snowline, with small cirque glaciers descending to an altitude of ~2300 m. During the last glacial maximum (LGM), small ice-caps existed on Mt Ruapehu and the Tongariro Massif (15 km to the NNE of Ruapehu), with a series of small (clast roundness, clast shape and textural characteristics associated with active and former glaciers on Mt Ruaephu and the Tongariro Massif, in order to assist in classifying the process-origin of sediments on glaciated volcanic mountains. Supraglacial inputs include rockfall, tephra, and avalanche material delivered to the surface of glaciers. Basal debris, where observed at the terminus of active cirque glaciers, consists mainly of incorporated fluvial material. Following deposition, reworking is mainly by proglacial streams, debris flows and lahars. Within the vicinity of glaciers, the dominant facies appear to be: (i) bouldery gravel with angular clasts on steep slopes surrounding glaciers, (ii) silty-sandy boulder gravel, with mainly subangular clasts, forming lateral moraines, (iii) boulder/cobble gravel with mainly subrounded clasts and associated laminated sediments representing fluvially-reworked material; and (iv) debris-avalanche deposits including fragmental rock clasts with an unsorted inter-clast matrix. As some of these deposits appear to include unambiguous indicators of glacial transport, interpretation of unconsolidated debris ridges on volcanic mountains should not necessarily exclude the contribution of glacial processes.

  7. Deep-water sediment bypass

    NARCIS (Netherlands)

    Stevenson, Christopher J.; Jackson, Christopher A L; Hodgson, David M.; Hubbard, Stephen M.; Eggenhuisen, Joris T.|info:eu-repo/dai/nl/322850274

    Submarine gravity flows are a key process for transporting large volumes of sediment from the continents to the deep sea. The location, volume, and character of the sediment bypassed by these flows dictates the areal extent and thickness of the associated deposits. Despite its importance, sediment

  8. Sediment contamination and associates laboratory-measured bioaccumulation in New York/New Jersey waterways

    Energy Technology Data Exchange (ETDEWEB)

    Rosman, L.B. [Army Corps of Engineers, New York, NY (United States); Barrows, E.S. [Battelle/Marine Sciences Lab., Sequim, WA (United States)

    1995-12-31

    Sediments from 10 New York/New Jersey waterways within the Hudson-Raritan Estuary and Long Island Sound were collected to depths representative of dredging activity. Composited core sediments representing each waterway were analyzed for metals, PAHs, PCBs, and pesticides. To assess bioaccumulation, sand worms (Nereis virens) and blunt-nose clams (Macoma nasuta) were exposed for 28 days to sediment composites and to New York Bight sediment. Tissues were analyzed for the same constituents as the sediment samples. The results highlight the range and magnitude of sediment contamination in NY/NJ waterways. Concentrations of some metals in sediments, compared with NY Bight sediment, were at least 10 times higher. Total PAHs reached 30,000 {micro}g/kg (dry weight). The sum of DDT, DDD, and DDE, the dominant pesticides, exceeded 3,000{micro}g/kg (dry weight). Total PCBs approached 3,000 {micro}g/kg (dry weight). Tissues exposed to sediments from several waterways bioaccumulated organic compounds at concentrations 10 times greater than those exposed to New York Bight sediments. Metals were bioaccumulated to a lesser degree. The presence and extent of bioaccumulated contaminants, along with sediment chemistry and benthic toxicity, create a profile characterizing each waterway.

  9. The effect of particle size on sorption of estrogens, androgens and progestagens in aquatic sediment

    Energy Technology Data Exchange (ETDEWEB)

    Sangster, Jodi L.; Oke, Hugues; Zhang, Yun; Bartelt-Hunt, Shannon L., E-mail: sbartelt2@unl.edu

    2015-12-15

    Highlights: • Two sediments were used to evaluate the effects of particle size on steroid sorption. • Sorption capacity did not increase with decreasing particle size for all steroids. • Particle interactions affect the distribution of steroids within the whole sediments. • Preferential sorption to fine particles was observed. - Abstract: There is growing concern about the biologic effects of steroid hormones in impacted waterways. There is increasing evidence of enhanced transport and biological effects stemming from steroid hormones associated with soils or sediments; however, there are limited studies evaluating how steroid hormone distribution between various particle sizes within whole sediments affects steroid fate. In this study, sorption of 17β-estradiol, estrone, progesterone, and testosterone was evaluated to different size fractions of two natural sediments, a silty loam and a sandy sediment, to determine the steroid sorption capacity to each fraction and distribution within the whole sediment. Sorption isotherms for all steroid hormones fit linear sorption models. Sorption capacity was influenced more by organic carbon content than particle size. Interactions between size fractions were found to affect the distribution of steroids within the whole sediments. All four steroids preferentially sorbed to the clay and colloids in the silty loam sediment at the lowest aqueous concentration (1 ng/L) and as aqueous concentration increased, the distribution of sorbed steroid was similar to the distribution by weight of each size fraction within the whole sediment. In the sandy sediment, preferential sorption to fine particles was observed.

  10. Establishing age constraints for Middle Pleistocene glaciofluvial sediments in the European Alpine foreland - new insights from luminescence dating

    Science.gov (United States)

    Lüthgens, Christopher; Rades, Eike F.; Bickel, Lukas; Fiebig, Markus

    2017-04-01

    This presentation summarises the outcome of a project funded by the Austrian Science Fund (FWF) which aimed at establishing new age constraints of deposits and landforms (glaciofluvial terraces) of the northern Alpine foreland (NAF) usually assigned to the Middle Pleistocene. The sediments under investigation were mostly deposited when large piedmont glaciers reached far into the Alpine foreland. Based on the concept of four Quaternary glacial advances to the NAF, which was already developed at the beginning of the 20th century by Penck and Brückner, specific morphostratigraphic units which can spatially be connected over the complete NAF area have been assigned to different glacial cycles and were subsequently correlated with the marine isotope record. However, numerical dating of the respective sediments had only been conducted to a limited extent, and previous studies report several methodological issues that limited the outcome with respect to the geochronological and chronostratigraphical value. In the course of the project, it became clear that the applicability of different optically stimulated luminescence (OSL) dating techniques for the targeted sediments was strongly dependent on the varying luminescence properties for samples from different catchment areas. By conducting a comparative luminescence dating approach, using different luminescence signals (quartz OSL, and feldspar infrared stimulated luminescence at 50°C (IR50) as well as post IR infrared stimulated luminescence at an elevated temperature (225°C, pIRIR225)), as well as using single aliquot and single grain dating techniques, it was i) possible to confirm but also to overcome prior problems of luminescence dating with the respective sediments ii) discern between samples that were well bleached prior to deposition and samples for which the luminescence signals were not properly reset, and iii) possible to establish reliable geochronological age constraints for the deposition of the sediments

  11. Site-specific features influence sediment stability of intertidal flats

    Directory of Open Access Journals (Sweden)

    E. C. Defew

    2002-01-01

    Full Text Available The factors that influence the sediment stability and the transport of estuarine mudflats are not yet fully understood but knowledge of them is essential in coastal engineering applications and pollution ecology studies. The suggestion that variation in predictive models of sediment stability might be due to site-specific characteristics is investigated using data from four estuarine mudflats (Eden Estuary, Scotland, the Biezelingsche Ham, Zandkreek, and Molenplaat mudflats in The Netherlands. These estuaries differ in their environmental conditions, macrofaunal species composition and local features (e.g. Enteromorpha mats, migratory biofilms. Stable and unstable sediments were compared, and mean chlorophyll-a concentrations and granulometry of the sediments were significantly different between the two groups. Step-wise multiple linear regressions were applied to the sediment stability data of all sites to establish the influences on erosion threshold of microphytobenthic biomass, water content, granulometry, organic carbon content and the abundance of dominant macrofaunal species. The stability of each site was influenced by different factors. Sediment stability of the Eden Estuary was affected by the Enteromorpha bloom; Biezelingsche Ham was influenced by the highly migratory nature of the diatom biofilms and the abundance of Corophium volutator; the polychaete worm Arenicola marina had a net negative effect on sediment stability of the Zandkreek; and the Molenplaat was influenced by microphytobenthic biomass. This research highlights the need for site-specific calibration of models and suggests that a universal proxy parameter for sediment stability is unlikely to be obtained. Keywords: sediment stability; erosion threshold; cohesive strength meter; microphytobenthos; Enteromorpha spp.

  12. Highlight summarization in golf videos using audio signals

    Science.gov (United States)

    Kim, Hyoung-Gook; Kim, Jin Young

    2008-01-01

    In this paper, we present an automatic summarization of highlights in golf videos based on audio information alone without video information. The proposed highlight summarization system is carried out based on semantic audio segmentation and detection on action units from audio signals. Studio speech, field speech, music, and applause are segmented by means of sound classification. Swing is detected by the methods of impulse onset detection. Sounds like swing and applause form a complete action unit, while studio speech and music parts are used to anchor the program structure. With the advantage of highly precise detection of applause, highlights are extracted effectively. Our experimental results obtain high classification precision on 18 golf games. It proves that the proposed system is very effective and computationally efficient to apply the technology to embedded consumer electronic devices.

  13. Sediment problems in reservoirs. Control of sediment deposits

    Energy Technology Data Exchange (ETDEWEB)

    Jacobsen, Tom

    1997-12-31

    When a reservoir is formed on a river, sediment will deposit in the reservoir. Such processes are unfortunate, for instance, for the implementation of hydroelectric energy. This thesis studies the problem of reservoir sedimentation and discusses methods of removing the sediments. Various aspects of reservoir sedimentation are discussed. Anthropogenic impacts seem to greatly affect the erosion processes. Temporal distribution is uneven, mainly because of the very large flood events. A world map showing the Reservoir Capacity: Annual Sediment Inflow ratio for reservoirs with volume equal to 10% of annual inflow has been prepared. The map shows that sedimentation is severe in the western parts of North and South America, eastern, southern and northern Africa, parts of Australia and most of Asia. The development of medium-sized reservoirs is difficult, as they are too large for conventional flushing technique and too small to store the sediment that accumulates during their economic lifetime. A computer model, SSIIM, was used with good results in a case study of two flood drawdown trials in Lake Roxburg, New Zealand. Two techniques have been developed that permits controlled suction of sediment and water into a pipe: the Slotted Pipe Sediment Sluicer (SPSS) and the Saxophone Sediment Sluicer (SSS). The techniques exploit the inflow pattern in through a slot in a pipe. An equation describing this inflow pattern was derived and verified experimentally. The SPSS is fixed near the reservoir bed, and sediment that deposits on top of it is removed in the sluicing process. The SSS sluices sediment from the surface of the sediment deposits. Some technical and economic conditions affecting the economics of sediment removal from reservoirs have been identified and studied. 79 refs., 112 figs., 14 tabs.

  14. Quantifying the dominant sources of sediment in a drained lowland agricultural catchment: The application of a thorium-based particle size correction in sediment fingerprinting

    Science.gov (United States)

    Foucher, Anthony; Laceby, Patrick J.; Salvador-Blanes, Sébastien; Evrard, Olivier; Le Gall, Marion; Lefèvre, Irène; Cerdan, Olivier; Rajkumar, Vignesh; Desmet, Marc

    2015-12-01

    Soil erosion is one of the main factors influencing land degradation and water quality at the global scale. Identifying the main sediment sources is therefore essential for the implementation of appropriate soil erosion mitigation measures. Accordingly, caesium-137 (137Cs) concentrations were used to determine the relative contribution of surface and subsurface erosion sources in a lowland drained catchment in France. As 137Cs concentrations are often dependent on particle size, specific surface area (SSA) and novel thorium (Th) based particle size corrections were applied. Surface and subsurface samples were collected to characterize the radionuclide properties of potential sources. Sediment samples were collected during one hydrological year and a sediment core was sampled to represent sediment accumulated over a longer temporal period. Additionally, sediment from tile drains was sampled to determine the radionuclide properties of sediment exported from the drainage network. A distribution modelling approach was used to quantify the relative sediment contributions from surface and subsurface sources. The results highlight a substantial enrichment in fine particles and associated 137Cs concentrations between the sources and the sediment. The application of both correction factors reduced this difference, with the Th correction providing a more accurate comparison of source and sediment samples than the SSA correction. Modelling results clearly indicate the dominance of surface sources during the flood events and in the sediment core. Sediment exported from the drainage network was modelled to originate predominantly from surface sources. This study demonstrates the potential of Th to correct for 137Cs particle size enrichment. More importantly, this research indicates that drainage networks may significantly increase the connectivity of surface sources to stream networks. Managing sediment transferred through drainage networks may reduce the deleterious effects of

  15. Highlighting material structure with transmission electron diffraction correlation coefficient maps.

    Science.gov (United States)

    Kiss, Ákos K; Rauch, Edgar F; Lábár, János L

    2016-04-01

    Correlation coefficient maps are constructed by computing the differences between neighboring diffraction patterns collected in a transmission electron microscope in scanning mode. The maps are shown to highlight material structural features like grain boundaries, second phase particles or dislocations. The inclination of the inner crystal interfaces are directly deduced from the resulting contrast. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Mental Health Disorders. Adolescent Health Highlight. Publication #2013-1

    Science.gov (United States)

    Murphey, David; Barry, Megan; Vaughn, Brigitte

    2013-01-01

    Mental disorders are diagnosable conditions characterized by changes in thinking, mood, or behavior (or some combination of these) that can cause a person to feel stressed out and impair his or her ability to function. These disorders are common in adolescence. This "Adolescent Health Highlight" presents the warning signs of mental disorders;…

  17. The Shortcomings of Medical Education Highlighted through Film

    Science.gov (United States)

    Mahajan, Pranav

    2012-01-01

    The aims of this report are to highlight the shortcomings in medical education. To use a student made short film as an example of how issues that cause medical student distress can be displayed. To show that the process of film-making is a useful tool in reflection. To display that film is an effective device in raising awareness. (Contains 3…

  18. Center Overview and UAV Highlights at NASA Ames Research Center

    Science.gov (United States)

    Feng, Deborah; Yan, Jerry Chi Yiu

    2017-01-01

    The PowerPoint presentation gives an overview of NASA Ames Research Center and its core competencies, as well as some of the highlights of Unmanned Aerial Vehicle (UAV) and Unmanned Aircraft Systems (UAS) accomplishments and innovations by researchers at Ames.

  19. Geothermal Today: 2003 Geothermal Technologies Program Highlights (Revised)

    Energy Technology Data Exchange (ETDEWEB)

    2004-05-01

    This outreach publication highlights milestones and accomplishments of the DOE Geothermal Technologies Program for 2003. Included in this publication are discussions of geothermal fundamentals, enhanced geothermal systems, direct-use applications, geothermal potential in Idaho, coating technology, energy conversion R&D, and the GeoPowering the West initiative.

  20. Tobacco Use. Adolescent Health Highlight. Publication #2012-33

    Science.gov (United States)

    Murphey, David; Barry, Megan; Vaughn, Brigitte; Terzian, Mary

    2012-01-01

    Cigarette smoking has steadily declined among adolescents during the last fifteen years, although use of some tobacco products, like cigars, has seen recent increases. However, large numbers of teens continue to use tobacco products. This "Adolescent Health Highlight" presents key research findings; describes prevalence and trends; illustrates…

  1. Students' reflections in a portfolio pilot: Highlighting professional issues.

    OpenAIRE

    Haffling, Ann-Christin; Beckman, Anders; Pahlmblad, Annika; Edgren, Gudrun

    2010-01-01

    Background: Portfolios are highlighted as potential assessment tools for professional competence. Although students' self-reflections are considered to be central in the portfolio, the content of reflections in practice-based portfolios is seldom analysed. Aim: To investigate whether students' reflections include sufficient dimensions of professional competence, notwithstanding a standardized portfolio format, and to evaluate students' satisfaction with the portfolio. Methods: Thi...

  2. Highlights of SK Mitra's Life-long Achievements

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 5; Issue 7. Highlights of S K Mitra's Life-long Achievements. M K Das Gupta. Article-in-a-Box Volume 5 Issue 7 July 2000 pp 5-5. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/005/07/0005-0005 ...

  3. Highlight: Youth summit in Senegal on unemployment and insecurity ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    2016-07-07

    Highlight: Youth summit in Senegal on unemployment and insecurity. July 07, 2016. An international forum for Francophone youth was held in Dakar, Senegal in mid-October, ahead of the 15th Sommet de la Francophonie to be held November 29-30, 2014. Some 250 youth debated their own futures during the two-day ...

  4. Advanced Education and Technology Business Plan, 2009-12. Highlights

    Science.gov (United States)

    Alberta Advanced Education and Technology, 2009

    2009-01-01

    Advanced Education and Technology provides strategic leadership for the development of the next generation economy in Alberta through the provision of accessible, affordable and quality learning opportunities for all Albertans and support for a dynamic and integrated innovation system. This paper provides the highlights of the business plan of the…

  5. Advanced Education and Technology Business Plan, 2010-13. Highlights

    Science.gov (United States)

    Alberta Advanced Education and Technology, 2010

    2010-01-01

    The Ministry of Advanced Education and Technology envisions Alberta's prosperity through innovation and lifelong learning. Advanced Education and Technology's mission is to lead the development of a knowledge-driven future through a dynamic and integrated advanced learning and innovation system. This paper presents the highlights of the business…

  6. HIV and Cancer Interaction Highlights Need to Address Disease Stigma

    Science.gov (United States)

    The global landscape of disease highlights disparities that exist between nations. An estimated 36 million people worldwide live with HIV and AIDS, of which only 1 million are located within the United States. While the diagnosis of a life-threatening disease can be devastating, individuals with HIV and AIDS frequently bear an additional burden of stigma and discrimination.

  7. Highlight: Canadian High Commissioners call IDRC a catalyst for ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    2016-04-15

    Apr 15, 2016 ... IDRC highlighted the issues of child marriage and health systems responses to early and forced marriages in Pakistan, including the IDRC-supported work of Shirkat Gah - Women Resource Centre. The Commissioners commended IDRC on the catalytic and transformative role it plays in the regions.

  8. Highlights of the 8th International Veterinary Immunology Symposium

    Science.gov (United States)

    Veterinary immunologists have expanded understanding of the immune systems for our companion animals and developed new vaccines and therapeutics. This manuscript summarizes the highlights of the 8th International Veterinary Immunology Symposium (8 th IVIS) held August 15th-19th, 2007, in Ouro Preto,...

  9. Trace element contamination in the nearshore sediments of the Tamiraparani estuary, Southeast coast of India.

    Science.gov (United States)

    Magesh, N S; Chandrasekar, N; Krishnakumar, S; Simon Peter, T

    2017-03-15

    The present study focused on the elemental distribution of nearshore environment and to understand the interrelationship between different parameters such as trace elements, organic matter, calcium carbonate and sediment texture. For this purpose, 24 surface samples were collected from the nearshore environment using a stainless steel Van Veen grab sampler. The above said parameters indicate that nearshore sediment transport, contaminants from estuarine source and anthropogenic activities deteriorates the sediment quality in the nearshore area. The enrichment factor reveals that the sediments are enriched with Pb, Co, Ni and Cr, whereas the geoaccumulation index highlights that the sediments are polluted with Pb, Ni and Co. The elevated concentration of Pb in the nearshore sediments are possibly from the port activities and thermal power plants situated in the north of the study area. Proper management of industrial effluents is needed to curb further metal pollution in the nearshore environment off Tamiraparani estuary. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Petrophysics of Palaeogene sediments

    DEFF Research Database (Denmark)

    Awadalkarim, Ahmed

    the in-situ vertical effective stress. The primary objectives of this Ph.D. study were: 1) to investigate and evaluate the influence of mineralogical composition, depositional texture and burial depth on petrophysical properties of Palaeogene sediments and to find out how the physical properties...... were obtained. A new approach for deriving reliable and accurate porosity of siliceous ooze is proposed here. The true density porosity was calculated by taking the number of electrons per unit volume into account. The true density porosity is similar to the corrected neutron porosity which indicates...... that the proposed interpretation is consistent. The proposed approach can be applied elsewhere and could be useful for petrophysicis comunity. The studied siliceous ooze intervals apparently do not contain hydrocarbons. X-ray diffraction (XRD) analyses and surface area by BET method have been done on 116 sediment...

  11. Sedimentation of active particles

    OpenAIRE

    Vachier, Jérémy; Marco G. Mazza

    2017-01-01

    Active particles convert energy from chemical, biochemical, or other processes into motion. Their collective motion has attracted enormous interest on account of the technological applications of artificial and biological particles. By combining theoretical arguments, and molecular dynamics simulations we explore the collective behavior of active particles under a gravity field in three dimensions. Dilute systems exhibit sedimentation, which we study with two approaches. Firstly, we solve ana...

  12. Sedimentation in Eelgrass

    OpenAIRE

    Ottosen, Mathias

    2015-01-01

    Protection of coastal areas has been a major political issue over the last decades. The coastline is in many places eroded by waves and current, and mechanical structures have been build to prevent the erosion. The abundance of the ma- rine flowering plant eelgrass (Zostera marina) has decline over the last century because of natural and anthropological reasons. Scientists have for many years thought that eelgrass enhances sedimentation by attenuating waves and cur- rent. Th...

  13. Magnetism of quaternary sediments

    Science.gov (United States)

    Heller, Friedrich

    Magnetism of Quaternary sediments was the topic of a well-attended symposium held during the 13th INQUA (International Union of Quaternary Research) congress in Beijing, China, August 2-9. More than 40 papers were delivered by scientists from Belgium, England, France, Germany, Japan, New Zealand, Sweden, Switzerland, Taiwan, the United States, the Soviet Union, Yugoslavia, and other countries. The host country contributed to a productive session that was part of the first large scientific meeting to take place in Beijing after the June 4, 1989, upheaval.Nearly half of the studies focused on paleomagnetic and rock magnetic properties of loess in Alaska, Central Asia, China, and New Zealand. Magnetostratigraphic polarity dating was done at some sections in the western (Shaw et al.) and central Chinese loess plateau (Bai and Hus; Wang and Evans; Yue). The interpretation of the polarity pattern found in the western loess plateau still is not unambiguous. In the central part, certain polarity boundaries, such as the Brunhes/Matuyama (B/M) boundary, are found in slightly different stratigraphic positions (Hus et al.; Yue). In deep-sea sediments the lock-in depth of natural remanent magnetization (NRM) at the B/M boundary seems to be a linear function of sedimentation rate (de Menocal et al.). Although the magnetization process in the Chinese loess is not well understood, detailed records of polarity transitions have been reported for the B/M and the Jaramillo R→N transition (Ma et al.; Rolph).

  14. Monitoring Large-Scale Sediment Transport Dynamics with Multibeam Sonar

    Science.gov (United States)

    Parsons, D. R.; Simmons, S. M.; Best, J. L.; Keevil, G. M.; Oberg, K.; Czuba, J. A.

    2009-05-01

    Multibeam Echo-Sounder systems have developed rapidly over recent decades and are routinely deployed to provide high-resolution bathymetric information in and range of environments. Modern data handling and storage technologies now facilitate the logging of the raw acoustic back-scatter information that was previously discarded by these systems. This paper describes methodologies that exploit this logging capability to quantify both the concentration and dynamics of suspended sediment within the water column. This development provides a multi-purpose tool for the holistic surveying of sediment transport dynamics by imaging suspended sediment concentration, the associated flows and providing concurrent high-resolution bathymetry. Results obtained a RESON 7125 MBES are presented from both well constrained dock-side testing and full field deployment over dune bedforms in the Mississippi. The capacity of the system to image suspended sediment structures is demonstrated and a novel methodology for estimating 2D flow velocities, based on frame cross-correlation methods, is introduced. The results demonstrate the capability of MBES systems to successfully map spatial and temporal variations in suspended sediment concentration throughout a 2D swath and application of the velocity estimation algorithms allow real-time holistic monitoring of turbulent flow processes and suspended sediment fluxes at a scale previously unrealisable. Turbulent flow over a natural dune bedform on the Mississippi is used to highlight the process information provided and the insights that can be gleaned for this technical development.

  15. Preferential sequestration of terrestrial organic matter in boreal lake sediments

    Science.gov (United States)

    Guillemette, François; von Wachenfeldt, Eddie; Kothawala, Dolly N.; Bastviken, David; Tranvik, Lars J.

    2017-04-01

    The molecular composition and origin has recently been demonstrated to play a critical role in the persistence of organic matter in lake water, but it is unclear to what degree chemical attributes and sources may also control settling and burial of organic matter in lake sediments. Here we compared the annual contribution of allochthonous and autochthonous sources to the organic matter settling in the water column and present in the sediments of 12 boreal lakes. We used the fluorescence properties and elemental composition of the organic matter to trace its origin and found a consistent pattern of increasing contribution of terrestrial compounds in the sediments as compared to the settling matter, with an annual average allochthony of 87% and 57%, respectively. Seasonal data revealed a predominance of in-lake-produced compounds sinking in the water column in summer. Yet only a slight concurrent decrease in the contribution of terrestrial C to lake sediments was observed during the same period, and sediment allochthony increased again to high levels in autumn. Our results reveal a preferential preservation of allochthonous matter in the sediments and highlight the role of lakes as sequesters of organic carbon primarily originating from the surrounding landscape.

  16. Effects of clay minerals and organic matter in formulated sediments on the bioavailability of sediment-associated uranium to the freshwater midge, Chironomus dilutus

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, Sarah E., E-mail: sarah.crawford@usask.ca [Toxicology Centre, University of Saskatchewan, 44 Campus Drive, Saskatoon, SK S7N 5B3 (Canada); Liber, Karsten, E-mail: karsten.liber@usask.ca [Toxicology Centre, University of Saskatchewan, 44 Campus Drive, Saskatoon, SK S7N 5B3 (Canada); School of Environment and Sustainability, 117 Science Place, University of Saskatchewan, Saskatoon, SK S7N 5C8 (Canada); Institute of Loess Plateau, 92 Wucheng Road, Shanxi University, Taiyuan, Shanxi 030006 (China)

    2015-11-01

    It is well established that bioavailability influences metal toxicity in aquatic ecosystems. However, the factors and mechanisms that influence uranium (U) bioavailability and toxicity in sediment have not been thoroughly evaluated, despite evidence that suggests different sediment components can influence the sorption and interaction of some metals. Given that dissolved U is generally accepted as being the primary bioavailable fraction of U, it is hypothesized that adsorption and interaction of U with different sediment components will influence the bioavailability of U in sediment. We investigated the effects of key sediment physicochemical properties on the bioavailability of U to a model freshwater benthic invertebrate, Chironomus dilutus. Several 10-day spiked sediment bioaccumulation experiments were performed, exposing C. dilutus larvae to a variety of formulated sediments spiked with different concentrations of U (5, 50 and/or 200 mg U/kg d.w.). Mean accumulation of U in C. dilutus larvae decreased significantly from 1195 to 10 mg U/kg d.w. as kaolin clay content increased from 0% to 60% in sediment spiked with 50 mg U/kg d.w. Similarly, higher organic matter content also resulted in a significant reduction of U bioaccumulation in C. dilutus larvae, indicating a reduction in U bioavailability. Concentrations of U in both the overlying water and sediment pore water displayed a strong positive relationship to U bioaccumulation in C. dilutus larvae (r{sup 2} = 0.77, p < 0.001 and r{sup 2} = 0.57, p < 0.001, respectively) for all experiments, while total U concentrations in the sediment had a poor relationship to U bioaccumulation (r{sup 2} = 0.10, p = 0.028). Results from this research confirm that sediment clay and organic matter content play a significant role in altering U bioavailability, which is important in informing risk assessments of U contaminated sites and in the development of site-specific sediment quality guidelines for U. - Highlights: • We

  17. Muddy marine sediments are gels

    Science.gov (United States)

    Dorgan, K. M.; Clemo, W. C.; Barry, M. A.; Johnson, B.

    2016-02-01

    Marine sediments cover 70% of the earth's surface, are important sites of carbon burial and nutrient regeneration, and provide habitat for diverse and abundant infaunal communities. The majority of these sediments are muds, in which bioturbation affects sediment structure and geochemical gradients. How infaunal activites result in particle mixing depends on the mechanical properties of muddy sediments. At the scale of burrowing animals, muds are elastic solids. Animals move through these elastic muds by extending crack-shaped burrows by fracture. The underlying mechanism driving this elasticity, however, has not been explicitly illustrated. Here, we test the hypothesis that the elastic behavior of muddy sediments is disrupted by removal of organic material by measuring fracture toughness and stiffness of manipulated and control sediments. Our results indicate that the mechanical responses of sediments to forces are governed by the muco-polymeric matrix of organic material. Similar effects of organic material oxidation were not observed in sands, indicating a clear mechanical distinction between fine- and coarse-grained sediments. Muddy sediments are gels, not fluids or granular materials, and models of how sediments respond to forces imposed by, e.g., organisms, gases, and ambient water should explicitly consider the role of organic material.

  18. Pleistocene glacitectonic landforms and sediments around central Magellan Strait, southernmost Chile: evidence for fast outlet glaciers with cold-based margins

    Science.gov (United States)

    Benn, Douglas I.; Clapperton, Chalmers M.

    2000-02-01

    Proglacial and subglacial glacitectonic sediments and landforms around the margins of the Strait of Magellan, southernmost Chile, record the advance and retreat of outlet glaciers of the Patagonian ice cap during the last glacial cycle. The spatial arrangement of glacitectonic landforms in the area is inferred to have resulted from the advance of ice lobes with cold-based margins and wet-based interiors. As the ice advanced, subglacial basins were excavated beneath the glacier margins and the eroded material was pushed up into thrust moraines, probably because frozen-bed conditions formed a thermal dam against the free drainage of subglacial meltwater. These ice-marginal glacitectonic landforms were then overridden and streamlined into drumlins and flutes as thicker, wet-based ice passed over the area. Evidence for permafrost near sea level in Patagonia during the last glaciation suggests that mean annual temperatures were several degrees lower than indicated by recent modelling studies. The results indicate that future modelling experiments should incorporate more realistic basal boundary conditions, particularly the presence of a weak deforming layer at the glacier bed, to improve climatic reconstructions of southern South America.

  19. Highlights of articles published in annals of nuclear medicine 2016

    Energy Technology Data Exchange (ETDEWEB)

    Jadvar, Hossein [University of Southern California, Division of Nuclear Medicine, Department of Radiology, Keck School of Medicine, Los Angeles, CA (United States)

    2017-10-15

    This article is the first installment of highlights of selected articles published during 2016 in the Annals of Nuclear Medicine, an official peer-reviewed journal of the Japanese Society of Nuclear Medicine. A companion article highlighting selected articles published during 2016 in the European Journal of Nuclear Medicine and Molecular Imaging, which is the official peer-reviewed journal of the European Association of Nuclear Medicine, will also appear in the Annals Nuclear Medicine. This new initiative by the respective journals will continue as an annual endeavor and is anticipated to not only enhance the scientific collaboration between Europe and Japan but also facilitate global partnership in the field of nuclear medicine and molecular imaging. (orig.)

  20. Using publication metrics to highlight academic productivity and research impact.

    Science.gov (United States)

    Carpenter, Christopher R; Cone, David C; Sarli, Cathy C

    2014-10-01

    This article provides a broad overview of widely available measures of academic productivity and impact using publication data and highlights uses of these metrics for various purposes. Metrics based on publication data include measures such as number of publications, number of citations, the journal impact factor score, and the h-index, as well as emerging metrics based on document-level metrics. Publication metrics can be used for a variety of purposes for tenure and promotion, grant applications and renewal reports, benchmarking, recruiting efforts, and administrative purposes for departmental or university performance reports. The authors also highlight practical applications of measuring and reporting academic productivity and impact to emphasize and promote individual investigators, grant applications, or department output. © 2014 by the Society for Academic Emergency Medicine.

  1. Automatic Segmentation and Inpainting of Specular Highlights for Endoscopic Imaging

    Directory of Open Access Journals (Sweden)

    Arnold Mirko

    2010-01-01

    Full Text Available Minimally invasive medical procedures have become increasingly common in today's healthcare practice. Images taken during such procedures largely show tissues of human organs, such as the mucosa of the gastrointestinal tract. These surfaces usually have a glossy appearance showing specular highlights. For many visual analysis algorithms, these distinct and bright visual features can become a significant source of error. In this article, we propose two methods to address this problem: (a a segmentation method based on nonlinear filtering and colour image thresholding and (b an efficient inpainting method. The inpainting algorithm eliminates the negative effect of specular highlights on other image analysis algorithms and also gives a visually pleasing result. The methods compare favourably to the existing approaches reported for endoscopic imaging. Furthermore, in contrast to the existing approaches, the proposed segmentation method is applicable to the widely used sequential RGB image acquisition systems.

  2. Spring Research Festival Highlighted on WHAG-TV | Poster

    Science.gov (United States)

    WHAG-TV (Hagerstown, Md.) visited Fort Detrick to highlight the 2015 Spring Research Festival (SRF), sponsored by the National Interagency Confederation for Biological Research (NICBR). Visit the WHAG-TV website to see the video broadcast, which aired May 6. The video was produced by WHAG Reporter Mallory Sofastaii. The video featured Linganore High School senior Rebecca Matthews, a Werner H. Kirsten student intern in the Human Retrovirus Pathogenesis Section, Vaccine Branch, NCI Center for Cancer Research; Lanessa Hill, public affairs specialist,

  3. Tourette syndrome research highlights 2015 [version 1; referees: 3 approved

    Directory of Open Access Journals (Sweden)

    Cheryl A. Richards

    2016-06-01

    Full Text Available We present selected highlights from research that appeared during 2015 on Tourette syndrome and other tic disorders. Topics include phenomenology, comorbidities, developmental course, genetics, animal models, neuroimaging, electrophysiology, pharmacology, and treatment. We briefly summarize articles whose results we believe may lead to new treatments, additional research or modifications in current models of TS.

  4. Recent results and highlights from the ATLAS experiment

    CERN Document Server

    Caforio, Davide; The ATLAS collaboration

    2016-01-01

    After a 2-year stop for the upgrade of the detector, since 2015 the ATLAS collaboration has collected data for over 20 fb-1 at 13 TeV centre-of-mass energy of pp collisions at the LHC. In this talk a summary of recent measurements of Higgs boson properties, BSM Higgs searches and the situation with the resonance at 750 GeV will be presented. Also some of most recent SM and Electroweak results will be highlighted.

  5. Recent results and highlights from the ATLAS experiment

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00211911; The ATLAS collaboration

    2016-01-01

    After a 2-year stop for the upgrade of the detector, since 2015 the ATLAS collaboration has collected data for over 20 fb$^{-1}$ at 13 TeV centre-of-mass energy of pp collisions at the LHC. In this talk a summary of recent measurements of Higgs boson properties, BSM Higgs searches and the status with the resonance at 750 GeV will be presented. Also some of most recent SM and electroweak results will be highlighted.

  6. Mercury contaminated sediment sites—An evaluation of remedial options

    Energy Technology Data Exchange (ETDEWEB)

    Randall, Paul M., E-mail: randall.paul@epa.gov [U.S. Environmental Protection Agency, Office of Research and Development, National Risk Management Research Laboratory, 26 West Martin Luther King Drive, Cincinnati, OH 45268 (United States); Chattopadhyay, Sandip, E-mail: Sandip.Chattopadhyay@tetratech.com [Tetra Tech, Inc., 250 West Court Street, Suite 200W, Cincinnati, OH 45202 (United States)

    2013-08-15

    Mercury (Hg) is a naturally-occurring element that is ubiquitous in the aquatic environment. Though efforts have been made in recent years to decrease Hg emissions, historically-emitted Hg can be retained in the sediments of aquatic bodies where they may be slowly converted to methylmercury (MeHg). Consequently, Hg in historically-contaminated sediments can result in high levels of significant exposure for aquatic species, wildlife and human populations consuming fish. Even if source control of contaminated wastewater is achievable, it may take a very long time, perhaps decades, for Hg-contaminated aquatic systems to reach relatively safe Hg levels in both water and surface sediment naturally. It may take even longer if Hg is present at higher concentration levels in deep sediment. Hg contaminated sediment results from previous releases or ongoing contributions from sources that are difficult to identify. Due to human activities or physical, chemical, or biological processes (e.g. hydrodynamic flows, bioturbation, molecular diffusion, and chemical transformation), the buried Hg can be remobilized into the overlying water. Hg speciation in the water column and sediments critically affect the reactivity (i.e. conversion of inorganic Hg(II) to MeHg), transport, and its exposure to living organisms. Also, geochemical conditions affect the activity of methylating bacteria and its availability for methylation. This review paper discusses remedial considerations (e.g. key chemical factors in fate and transport of Hg, source characterization and control, environmental management procedures, remediation options, modeling tools) and includes practical case studies for cleaning up Hg-contaminated sediment sites. -- Highlights: ► Managing mercury-contaminated sediment sites are challenging to remediate. ► Remediation technologies are making a difference in managing these sites. ► Partitioning plays a dominant role in the distribution of mercury species. ► Mathematical

  7. Consistency between 2D-3D Sediment Transport models

    Science.gov (United States)

    Villaret, Catherine; Jodeau, Magali

    2017-04-01

    Sediment transport models have been developed and applied by the engineering community to estimate transport rates and morphodynamic bed evolutions in river flows, coastal and estuarine conditions. Environmental modelling systems like the open-source Telemac modelling system include a hierarchy of models from 1D (Mascaret), 2D (Telemac-2D/Sisyphe) and 3D (Telemac-3D/Sedi-3D) and include a wide range of processes to represent sediment flow interactions under more and more complex situations (cohesive, non-cohesive and mixed sediment). Despite some tremendous progresses in the numerical techniques and computing resources, the quality/accuracy of model results mainly depend on the numerous choices and skills of the modeler. In complex situations involving stratification effects, complex geometry, recirculating flows… 2D model assumptions are no longer valid. A full 3D turbulent flow model is then required in order to capture the vertical mixing processes and to represent accurately the coupled flow/sediment distribution. However a number of theoretical and numerical difficulties arise when dealing with sediment transport modelling in 3D which will be high-lighted : (1) Dependency of model results to the vertical grid refinement and choice of boundary conditions and numerical scheme (2) The choice of turbulence model determines also the sediment vertical distribution which is governed by a balance between the downward settling term and upward turbulent diffusion. (3) The use of different numerical schemes for both hydrodynamics (mean and turbulent flow) and sediment transport modelling can lead to some inconsistency including a mismatch in the definition of numerical cells and definition of boundary conditions. We discuss here those present issues and present some detailed comparison between 2D and 3D simulations on a set of validation test cases which are available in the Telemac 7.2 release using both cohesive and non-cohesive sediments.

  8. Identifying sediment sources in a drained lowland agricultural catchment: the application of a novel thorium-based particle size correction in sediment fingerprinting

    Science.gov (United States)

    Laceby, J. P.; Le Gall, M.; Foucher, A.; Salvador-Blanes, S.; Evrard, O.; Lefèvre, I.; Cerdan, O.; Desmet, M.

    2015-12-01

    Soil erosion is one of the main processes influencing land and water degradation at the global scale. Identifying the main sediment sources is therefore essential for effective soil erosion management. Accordingly, caesium-137 (137Cs) concentrations were used to quantify the relative contribution of surface and subsurface erosion sources in a lowland drained catchment in France. As 137Cs concentrations are often dependent on particle size, specific surface area (SSA) and novel Thorium (Th) based particle size corrections were applied. Surface and subsurface samples were collected to characterize the radionuclide properties of potential sources. Sediment samples were collected during one hydrological year and a sediment core was sampled to represent sediment accumulated over a longer temporal period. Additionally, sediment from tile drains was sampled to determine the radionuclide properties of sediment exported from the drainage network. The results highlight a substantial enrichment in fine particles and associated 137Cs concentrations between the sources and the sediment. The application of both correction factors reduced this difference, with the Th correction providing a more accurate comparison of source and sediment samples than the SSA correction. Modelling results clearly indicate the dominance of surface sources during the flood events and in the sediment core. Sediment exported from the drainage network was modelled to originate predominantly from surface sources. This study demonstrates the potential of Th to correct for 137Cs particle size enrichment. More importantly, this research indicates that drainage networks may significantly increase the connectivity of surface sources to stream networks. Managing sediment transferred through drainage networks may reduce the deleterious effects of suspended sediment loads on riverine systems in similar lowland drained agricultural catchments.

  9. Maximum Recoverable Gas from Hydrate Bearing Sediments by Depressurization

    KAUST Repository

    Terzariol, Marco

    2017-11-13

    The estimation of gas production rates from hydrate bearing sediments requires complex numerical simulations. This manuscript presents a set of simple and robust analytical solutions to estimate the maximum depressurization-driven recoverable gas. These limiting-equilibrium solutions are established when the dissociation front reaches steady state conditions and ceases to expand further. Analytical solutions show the relevance of (1) relative permeabilities between the hydrate free sediment, the hydrate bearing sediment, and the aquitard layers, and (2) the extent of depressurization in terms of the fluid pressures at the well, at the phase boundary, and in the far field. Close form solutions for the size of the produced zone allow for expeditious financial analyses; results highlight the need for innovative production strategies in order to make hydrate accumulations an economically-viable energy resource. Horizontal directional drilling and multi-wellpoint seafloor dewatering installations may lead to advantageous production strategies in shallow seafloor reservoirs.

  10. Sediment Geo-Probe System

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Provides wideband in situ measurement capability of compressional wave speed and attenuation and their spatial variability in marine sediments.DESCRIPTION:...

  11. Glacimarine environments: processes and sediments

    National Research Council Canada - National Science Library

    Dowdeswell, J. A; Scourse, James D

    1990-01-01

    .... Sediments released from glaciers grounded in tidewater, floating ice shelves, ice tongues, icebergs and sea ice form complex sequences governed by glaciological, oceanographic, sedimentary and biogenic controls...

  12. Seasonal sediment dynamics on the Barcelona inner shelf (NW Mediterranean): A small Mediterranean river- and wave-dominated system

    Science.gov (United States)

    López, L.; Guillén, J.; Palanques, A.; Grifoll, M.

    2017-08-01

    The seasonal pattern of sediment dynamics on an inner shelf characterized by the presence of sediment delivered by a small, mountainous river (with a ;flash-flood; regime) was investigated. Near-bottom suspended sediment fluxes across the shelf (i.e. 20, 30 and 40 m water depth) were estimated using observations from three benthic tripods deployed from September 2007 to June 2008. Near-bottom sediment resuspension was controlled by wave-induced currents and river-born sediment availability, whereas the shelf currents played a secondary role. Fourteen sediment transport events were identified (eight in autumn, two in winter and four in spring), with transport rates according to storm intensity and sediment availability. These few energetic events induced a large percentage of the cumulative sediment transport near the bottom. However, the lack of proportionality between suspended sediment transport rates and the combined wave-current bottom shear stress in some events highlights the importance of the sequence of events in sediment dynamics. Since wave activity, hydrography and river discharges display a strong seasonal pattern in the NW Mediterranean, the resulting sediment dynamics across the shelf also correspond to a seasonal cycle. This seasonal variability leads to a temporal evolution of the bottom grain size (coarser in winter) and the near-bottom sediment transport rates (higher in spring and autumn) which is consistent with the seasonal pattern of the hydrodynamic events and the river discharge load.

  13. Climate variability, soil conservation, and reservoir sedimentation

    Science.gov (United States)

    Rivers carry sediments which, upon entering a reservoir, settle to the bottom. The process of deposition and gradual accumulation of sediments in the reservoir is referred to as reservoir sedimentation. As reservoir sedimentation progresses, the storage capacity allocated for sediment deposition wil...

  14. Clinical highlights from the 2016 European Respiratory Society International Congress

    Directory of Open Access Journals (Sweden)

    Nicolas Kahn

    2017-04-01

    Full Text Available This article contains highlights and a selection of the scientific advances from the European Respiratory Society (ERS Clinical Assembly (Assembly 1 and its six respective groups (Groups 1.1–1.6 that were presented at the 2016 ERS International Congress in London, UK. The most relevant topics for clinicians will be discussed, covering a wide range of areas including clinical problems, rehabilitation and chronic care, thoracic imaging, interventional pulmonology, diffuse and parenchymal lung diseases, and general practice and primary care. In this comprehensive review, the newest research and actual data will be discussed and put into perspective.

  15. Realizing a Clean Energy Future: Highlights of NREL Analysis (Brochure)

    Energy Technology Data Exchange (ETDEWEB)

    2013-12-01

    Profound energy system transformation is underway. In Hawaiian mythology, Maui set out to lasso the sun in order to capture its energy. He succeeded. That may have been the most dramatic leap forward in clean energy systems that the world has known. Until now. Today, another profound transformation is underway. A combination of forces is taking us from a carbon-centric, inefficient energy system to one that draws from diverse energy sources - including the sun. NREL analysis is helping guide energy systems policy and investment decisions through this transformation. This brochure highlights NREL analysis accomplishments in the context of four thematic storylines.

  16. Hot subluminous stars: Highlights from the MUCHFUSS and Kepler missions

    Directory of Open Access Journals (Sweden)

    Geier S.

    2013-03-01

    Full Text Available Research into hot subdwarf stars is progressing rapidly. We present recent important discoveries. First we review the knowledge about magnetic fields in hot subdwarfs and highlight the first detection of a highly-magnetic, helium-rich sdO star. We briefly summarize recent discoveries based on Kepler light curves and finally introduce the closest known sdB+WD binary discovered by the MUCHFUSS project and discuss its relevance as a progenitor of a double-detonation type Ia supernova.

  17. Annual scientific meeting--American Headache Society Washington 2011--highlights.

    Science.gov (United States)

    Purdy, R Allan

    2012-05-01

    The 53rd Annual Scientific Meeting of the American Headache Society was held in Washington from June 2 to 5, 2011. Important clinical and basic science information was presented at this meeting. This is a review of the highlights of that meeting dealing in many areas of headache medicine. Once again, this meeting, which is the premier scientific meeting of the American Headache Society, provided lots of new and exciting information about multiple facets of migraine headache and other disorders. © 2012 American Headache Society.

  18. Status, performance and scientific highlights from the MAGIC telescope system

    Energy Technology Data Exchange (ETDEWEB)

    Doert, Marlene [Technische Universitaet Dortmund (Germany); Ruhr-Universitaet Bochum (Germany); Collaboration: MAGIC-Collaboration

    2015-07-01

    The MAGIC telescopes are a system of two 17 m Imaging Air Cherenkov Telescopes, which are located at 2200 m above sea level at the Roque de Los Muchachos Observatory on the Canary Island of La Palma. In this presentation, we report on recent scientific highlights gained from MAGIC observations in the galactic and the extragalactic regime. We also present the current status and performance of the MAGIC system after major hardware upgrades in the years 2011 to 2014 and give an overview of future plans.

  19. Prediction of sediment load by sediment rating curve and neural ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Earth System Science; Volume 122; Issue 5. Prediction of sediment load by sediment rating curve and neural network (ANN) in El Kebir catchment, Algeria. Z A Boukhrissa K Khanchoul Y Le Bissonnais M Tourki. Volume 122 Issue 5 October 2013 pp 1303-1312 ...

  20. Optical sedimentation recorder

    Science.gov (United States)

    Bishop, James K.B.

    2014-05-06

    A robotic optical sedimentation recorder is described for the recordation of carbon flux in the oceans wherein both POC and PIC particles are captured at the open end of a submersible sampling platform, the captured particles allowed to drift down onto a collection plate where they can be imaged over time. The particles are imaged using three separate light sources, activated in sequence, one source being a back light, a second source being a side light to provide dark field illumination, and a third source comprising a cross polarized light source to illuminate birefringent particles. The recorder in one embodiment is attached to a buoyancy unit which is capable upon command for bringing the sedimentation recorder to a programmed depth below the ocean surface during recordation mode, and on command returning the unit to the ocean surface for transmission of recorded data and receipt of new instructions. The combined unit is provided with its own power source and is designed to operate autonomously in the ocean for extended periods of time.

  1. Towards science-based sediment quality standards—Effects of field-collected sediments in rainbow trout (Oncorhynchus mykiss)

    Energy Technology Data Exchange (ETDEWEB)

    Brinkmann, Markus, E-mail: markus.brinkmann@bio5.rwth-aachen.de [Department of Ecosystem Analysis, Institute for Environmental Research, RWTH Aachen University, Worringerweg 1, 52074 Aachen (Germany); Eichbaum, Kathrin; Reininghaus, Mathias; Koglin, Sven [Department of Ecosystem Analysis, Institute for Environmental Research, RWTH Aachen University, Worringerweg 1, 52074 Aachen (Germany); Kammann, Ulrike [Thünen-Institute of Fisheries Ecology, Palmaille 9, 22767 Hamburg (Germany); Baumann, Lisa; Segner, Helmut [Centre for Fish and Wildlife Health, Vetsuisse Faculty, University of Bern, Länggassstr. 122, 3012 Bern (Switzerland); Zennegg, Markus [Swiss Federal Institute for Materials Science and Technology (Empa), Laboratory for Advanced Analytical Technologies, Überlandstrasse 129, 8600 Dübendorf (Switzerland); Buchinger, Sebastian; Reifferscheid, Georg [Department G3: Biochemistry, Ecotoxicology, Federal Institute of Hydrology (BFG), Am Mainzer Tor 1, 56068 Koblenz (Germany); Hollert, Henner, E-mail: henner.hollert@bio5.rwth-aachen.de [Department of Ecosystem Analysis, Institute for Environmental Research, RWTH Aachen University, Worringerweg 1, 52074 Aachen (Germany); College of Resources and Environmental Science, Chongqing University, 1 Tiansheng Road Beibei, Chongqing 400715 (China); College of Environmental Science and Engineering and State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, 1239 Siping Road, Shanghai (China); State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University (China)

    2015-09-15

    Highlights: • Particle-bound DLCs were readily bioavailable during re-suspension of sediments. • DLC uptake and effects in fish were proportional to the concentration in sediments. • Responses of biomarkers reflected the contamination levels of different sediments. • Cyp1a mRNA expression and EROD activity in livers of fish responded immediately. • Histopathological lesions were strong indicators of potential long-term effects. - Abstract: Sediments can act as long-term sinks for environmental pollutants. Within the past decades, dioxin-like compounds (DLCs) such as polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs) have attracted significant attention in the scientific community. To investigate the time- and concentration-dependent uptake of DLCs and PAHs in rainbow trout (Oncorhynchus mykiss) and their associated toxicological effects, we conducted exposure experiments using suspensions of three field-collected sediments from the rivers Rhine and Elbe, which were chosen to represent different contamination levels. Five serial dilutions of contaminated sediments were tested; these originated from the Prossen and Zollelbe sampling sites (both in the river Elbe, Germany) and from Ehrenbreitstein (Rhine, Germany), with lower levels of contamination. Fish were exposed to suspensions of these dilutions under semi-static conditions for 90 days. Analysis of muscle tissue by high resolution gas chromatography and mass spectrometry and of bile liquid by high-performance liquid chromatography showed that particle-bound PCDD/Fs, PCBs and PAHs were readily bioavailable from re-suspended sediments. Uptake of these contaminants and the associated toxicological effects in fish were largely proportional to their sediment concentrations. The changes in the investigated biomarkers closely reflected the different sediment contamination levels: cytochrome P450 1A m

  2. CO2 Emissions From Fuel Combustion. Highlights. 2013 Edition

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-07-01

    In the lead-up to the UN climate negotiations in Warsaw, the latest information on the level and growth of CO2 emissions, their source and geographic distribution will be essential to lay the foundation for a global agreement. To provide input to and support for the UN process, the IEA is making available for free download the ''Highlights'' version of CO2 Emissions from Fuel Combustion now for sale on IEA Bookshop. This annual publication contains, for more than 140 countries and regions: estimates of CO2 emissions from 1971 to 2011; selected indicators such as CO2/GDP, CO2/capita, CO2/TPES and CO2/kWh; a decomposition of CO2 emissions into driving factors; and CO2emissions from international marine and aviation bunkers, key sources, and other relevant information. The nineteenth session of the Conference of the Parties to the Climate Change Convention (COP-19), in conjunction with the ninth meeting of the Parties to the Kyoto Protocol (CMP 9), met in Warsaw, Poland from 11 to 22 November 2013. This volume of ''Highlights'', drawn from the full-scale study, was specially designed for delegations and observers of the meeting in Warsaw.

  3. Princeton Plasma Physics Laboratory FY2003 Annual Highlights

    Energy Technology Data Exchange (ETDEWEB)

    Editors: Carol A. Phillips; Anthony R. DeMeo

    2004-08-23

    The Princeton Plasma Physics Laboratory FY2003 Annual Highlights report provides a summary of the activities at the Laboratory for the fiscal year--1 October 2002 through 30 September 2003. The report includes the Laboratory's Mission and Vision Statements, a message ''From the Director,'' summaries of the research and engineering activities by project, and sections on Technology Transfer, the Graduate and Science Education Programs, Awards and Honors garnered by the Laboratory and the employees, and the Year in Pictures. There is also a listing of the Laboratory's publications for the year and a section of the abbreviations, acronyms, and symbols used throughout the report. In the PDF document, links have been created from the Table of Contents to each section. You can also return to the Table of Contents from the beginning page of each section. The PPPL Highlights for fiscal year 2003 is also available in hardcopy format. To obtain a copy e-mail Publications and Reports at: pub-reports@pppl.gov. Be sure to include your complete mailing address

  4. Sediment flux and the Anthropocene.

    Science.gov (United States)

    Syvitski, James P M; Kettner, Albert

    2011-03-13

    Data and computer simulations are reviewed to help better define the timing and magnitude of human influence on sediment flux--the Anthropocene epoch. Impacts on the Earth surface processes are not spatially or temporally homogeneous. Human influences on this sediment flux have a secondary effect on floodplain and delta-plain functions and sediment dispersal into the coastal ocean. Human impact on sediment production began 3000 years ago but accelerated more widely 1000 years ago. By the sixteenth century, societies were already engineering their environment. Early twentieth century mechanization has led to global signals of increased sediment flux in most large rivers. By the 1950s, this sediment disturbance signal reversed for many rivers owing to the proliferation of dams, and sediment load reduction below pristine conditions is the dominant signal today. A delta subsidence signal began in the 1930s and is now a dominant signal in terms of sea level for many coastal environments, overwhelming even the global warming imprint on sea level. Humans have engineered how most water and sediment are discharged into the coastal ocean. Hyperpycnal flow events have become more common for some rivers, and less common for other rivers. Bottom trawling is now widespread, suggesting that even continental shelves have received a significant but as yet quantified Anthropocene impact. The Anthropocene attains the level of a geological climate event, such as that seen in the transition between the Pleistocene and the Holocene.

  5. Intensive landfarming of contaminated sediments

    NARCIS (Netherlands)

    Wieggers, H.J.J.; Bezemer, H.W.

    1995-01-01

    The biodegradation of polycyclic aromatic hydrocarbons (PAH) and mineral oil was investigated in heavily and normally polluted sediments. The aims of the research were: to improve the knowledge of dewatering and ripening of sediments in an open land-farm, to quantify the biodegradation in two

  6. Reservoir sedimentation; a literature survey

    NARCIS (Netherlands)

    Sloff, C.J.

    1991-01-01

    A survey of literature is made on reservoir sedimentation, one of the most threatening processes for world-wide reservoir performance. The sedimentation processes, their impacts, and their controlling factors are assessed from a hydraulic engineering point of view with special emphasis on

  7. Landscape-scale analysis of wetland sediment deposition from four tropical cyclone events.

    Directory of Open Access Journals (Sweden)

    Andrew W Tweel

    Full Text Available Hurricanes Katrina, Rita, Gustav, and Ike deposited large quantities of sediment on coastal wetlands after making landfall in the northern Gulf of Mexico. We sampled sediments deposited on the wetland surface throughout the entire Louisiana and Texas depositional surfaces of Hurricanes Katrina, Rita, Gustav, and the Louisiana portion of Hurricane Ike. We used spatial interpolation to model the total amount and spatial distribution of inorganic sediment deposition from each storm. The sediment deposition on coastal wetlands was an estimated 68, 48, and 21 million metric tons from Hurricanes Katrina, Rita, and Gustav, respectively. The spatial distribution decreased in a similar manner with distance from the coast for all hurricanes, but the relationship with distance from the storm track was more variable between events. The southeast-facing Breton Sound estuary had significant storm-derived sediment deposition west of the storm track, whereas sediment deposition along the south-facing coastline occurred primarily east of the storm track. Sediment organic content, bulk density, and grain size also decreased significantly with distance from the coast, but were also more variable with respect to distance from the track. On average, eighty percent of the mineral deposition occurred within 20 km from the coast, and 58% was within 50 km of the track. These results highlight an important link between tropical cyclone events and coastal wetland sedimentation, and are useful in identifying a more complete sediment budget for coastal wetland soils.

  8. The influence of turbulent bursting on sediment resuspension under unidirectional currents

    Directory of Open Access Journals (Sweden)

    S. Salim

    2017-07-01

    Full Text Available Laboratory experiments were conducted in an open channel flume with a flat sandy bed to examine the role of turbulence on sediment resuspension. An acoustic Doppler velocimeter (ADV was used to measure the instantaneous three-dimensional velocity components and acoustic backscatter as a proxy to suspended sediment concentration. Estimates of sediment transport assume that there is a mean critical velocity that needs to be exceeded before sediment transport is initiated. This approach does not consider the turbulent flow field that may initiate sediment resuspension through event-based processes such as the bursting phenomenon. In this paper, laboratory measurements were used to examine the sediment resuspension processes below and above the mean critical velocity. The results within a range above and below the measured mean critical velocity suggested that (1 the contribution of turbulent bursting events remained identical in both experimental conditions, (2 ejection and sweep events contributed more to the total sediment flux than up-acceleration and down-deceleration events, and (3 wavelet transform revealed a correlation between the momentum and sediment flux in both test conditions. Such similarities in conditions above and below the measured mean critical velocity highlight the need to re-evaluate the accuracy of a single time-averaged mean critical velocity for the initiation of sediment entrainment.

  9. Landscape-scale analysis of wetland sediment deposition from four tropical cyclone events.

    Science.gov (United States)

    Tweel, Andrew W; Turner, R Eugene

    2012-01-01

    Hurricanes Katrina, Rita, Gustav, and Ike deposited large quantities of sediment on coastal wetlands after making landfall in the northern Gulf of Mexico. We sampled sediments deposited on the wetland surface throughout the entire Louisiana and Texas depositional surfaces of Hurricanes Katrina, Rita, Gustav, and the Louisiana portion of Hurricane Ike. We used spatial interpolation to model the total amount and spatial distribution of inorganic sediment deposition from each storm. The sediment deposition on coastal wetlands was an estimated 68, 48, and 21 million metric tons from Hurricanes Katrina, Rita, and Gustav, respectively. The spatial distribution decreased in a similar manner with distance from the coast for all hurricanes, but the relationship with distance from the storm track was more variable between events. The southeast-facing Breton Sound estuary had significant storm-derived sediment deposition west of the storm track, whereas sediment deposition along the south-facing coastline occurred primarily east of the storm track. Sediment organic content, bulk density, and grain size also decreased significantly with distance from the coast, but were also more variable with respect to distance from the track. On average, eighty percent of the mineral deposition occurred within 20 km from the coast, and 58% was within 50 km of the track. These results highlight an important link between tropical cyclone events and coastal wetland sedimentation, and are useful in identifying a more complete sediment budget for coastal wetland soils.

  10. The kinetics of denitrification in permeable sediments

    DEFF Research Database (Denmark)

    Evrard, Victor; Glud, Ronnie N.; Cook, Perran L. M.

    2013-01-01

    Permeable sediments comprise the majority of shelf sediments, yet the rates of denitrification remain highly uncertain in these environments. Computational models are increasingly being used to understand the dynamics of denitrification in permeable sediments, which are complex environments to st...

  11. DESIGN CONSIDERATION INVOLVING ACTIVE SEDIMENT CAPS (PRESENTATION)

    Science.gov (United States)

    When contaminated sediments pose unacceptable risks to human health and the environment, management activities such as removal, treatment, or isolation of contaminated sediments may be required. Various capping designs are being considered for isolating contaminated sediment are...

  12. DESIGN CONSIDERATION INVOLVING ACTIVE SEDIMENT CAPS

    Science.gov (United States)

    When contaminated sediments pose unacceptable risks to human health and the environment, management activities such as removal, treatment, or isolation of contaminated sediments may be required. Various capping designs are being considered for isolating contaminated sediment are...

  13. SOFIA: first science highlights and future science potential

    Science.gov (United States)

    Zinnecker, H.

    2013-06-01

    SOFIA, the Stratospheric Observatory for Infrared Astronomy, is a joint project between NASA and the German Aerospace Agency (DLR) to develop and operate a 2.5 m airborne telescope in a highly modified Boeing 747SP aircraft that can fly as high as 45 000 feet (13.7 km). This is above 99.8 % of the precipitable water vapor which blocks much of the mid- and far-infrared radiation from reaching ground-based telescopes. In this review, we briefly discuss the characteristics of the Observatory and present a number of early science highlights obtained with the FORCAST camera in 5-40 micron spectral region and with the GREAT heterodyne spectrometer in the 130-240 micron spectral region. The FORCAST images in Orion show the discovery of a new high-mass protostar (IRc4), while GREAT observations at 1 km s-1 velocity resolution detected velocity-resolved, redshifted ammonia spectra at 1.81 THz in absorption against several strong far-infrared dust continuum sources, clear evidence of substantial protostellar infall onto massive (non-ionizing) protostars. These powerful new data allow us to determine how massive stars form in our Galaxy. Another highlight is the stunning image taken by FORCAST that reveals the transient circumnuclear 1.5 pc radius (dust) ring around our Galactic center, heated by hundreds of massive stars in the young nuclear star cluster. The GREAT heterodyne spectrometer also observed the circumnuclear ring in highly excited CO rotational lines, indicative of emission from warm dense molecular gas with broad velocity structure, perhaps due to local shock heating. GREAT also made superb mapping observations of the [C II] fine structure cooling line at 158 microns, for example in M17-SW molecular cloud-star cluster interface, observations which disprove the simple canonical photodissociation models. The much better baseline stability of the GREAT receivers (compared to Herschel HIFI) allows efficient on-the-fly mapping of extended [C II] emission in our

  14. Ensemble Modeling of Suspended Sediment in Steep Mountain Catchments

    Science.gov (United States)

    Stewart, J.; Raseman, W. J.; Kasprzyk, J. R.; Livneh, B.

    2016-12-01

    Climatic and land cover changes present important uncertainties into the rates of soil erosion and sedimentation in watersheds. Soil erosion adds constituents to streams, altering water chemistry and streambed morphology, which can adversely affect aquatic life and poses a critical challenge for water treatment and reservoir management. The goal of this research is to establish estimates of sediment transport within large-scale mountainous catchments (>1000 km2). As sedimentation rates are impacted by numerous physical processes including soil, land cover, slope and climate; the results from seven models will be presented to quantify uncertainty and improve predictability. A broader inquiry made here is into the efficacy of model structure under different conditions. We present the results from empirical, stochastic, conceptual and physical models. These include empirical models: monovariate rating curve, multivariate regression and the Modified Universal Soil Loss Equation (MUSLE), to models with conceptual components: Soil Water Assessment Tool (SWAT) to more physically based models: Water Erosion Prediction Project (WEPP), Precipitation Runoff Modeling System (PRMS) and Distributed Hydrology Soil Vegetation Model (DHSVM). Key uncertainties will be characterized resulting from forcing inputs, parameter selection, scale discretization, and model structure. Calibration results from a multi-objective optimization routine will be presented that optimize parameters and identify performance trade-offs that will be used to develop uncertainty estimates in both streamflow and sediment projections. The outcomes of this research will highlight critical issues relevant to large-scale hydrologic and suspended sediment prediction initiatives.

  15. Hindered erosion: The biological mediation of noncohesive sediment behavior

    Science.gov (United States)

    Chen, X. D.; Zhang, C. K.; Paterson, D. M.; Thompson, C. E. L.; Townend, I. H.; Gong, Z.; Zhou, Z.; Feng, Q.

    2017-06-01

    Extracellular polymeric substances (EPS) are ubiquitous on tidal flats but their impact on sediment erosion has not been fully understood. Laboratory-controlled sediment beds were incubated with Bacillus subtilis for 5, 10, 16, and 22 days before the erosion experiments, to study the temporal and spatial variations in sediment stability caused by the bacterial secreted EPS. We found the biosedimentary systems showed different erosional behavior related to biofilm maturity and EPS distribution. In the first stage (5 days), the biosedimentary bed was more easily eroded than the clean sediment. With increasing growth period, bound EPS became more widely distributed over the vertical profile resulting in bed stabilization. After 22 days, the bound EPS was highly concentrated within a surface biofilm, but a relatively high content also extended to a depth of 5 mm and then decayed sharply with depth. The biofilm increased the critical shear stress of the bed and furthermore, it enabled the bed to withstand threshold conditions for an increased period of time as the biofilm degraded before eroding. After the loss of biofilm protection, the high EPS content in the sublayers continued to stabilize the sediment (hindered erosion) by binding individual grains, as visualized by electron microscopy. Consequently, the bed strength did not immediately revert to the abiotic condition but progressively adjusted, reflecting the depth profile of the EPS. Our experiments highlight the need to treat the EPS-sediment conditioning as a bed-age associated and depth-dependent variable that should be included in the next generation of sediment transport models.

  16. Mycophagous rove beetles highlight diverse mushrooms in the Cretaceous

    Science.gov (United States)

    Cai, Chenyang; Leschen, Richard A. B.; Hibbett, David S; Xia, Fangyuan; Huang, Diying

    2017-01-01

    Agaricomycetes, or mushrooms, are familiar, conspicuous and morphologically diverse Fungi. Most Agaricomycete fruiting bodies are ephemeral, and their fossil record is limited. Here we report diverse gilled mushrooms (Agaricales) and mycophagous rove beetles (Staphylinidae) from mid-Cretaceous Burmese amber, the latter belonging to Oxyporinae, modern members of which exhibit an obligate association with soft-textured mushrooms. The discovery of four mushroom forms, most with a complete intact cap containing distinct gills and a stalk, suggests evolutionary stasis of body form for ∼99 Myr and highlights the palaeodiversity of Agaricomycetes. The mouthparts of early oxyporines, including enlarged mandibles and greatly enlarged apical labial palpomeres with dense specialized sensory organs, match those of modern taxa and suggest that they had a mushroom feeding biology. Diverse and morphologically specialized oxyporines from the Early Cretaceous suggests the existence of diverse Agaricomycetes and a specialized trophic interaction and ecological community structure by this early date. PMID:28300055

  17. Replication data collection highlights value in diversity of replication attempts.

    Science.gov (United States)

    DeSoto, K Andrew; Schweinsberg, Martin

    2017-03-14

    Researchers agree that replicability and reproducibility are key aspects of science. A collection of Data Descriptors published in Scientific Data presents data obtained in the process of attempting to replicate previously published research. These new replication data describe published and unpublished projects. The different papers in this collection highlight the many ways that scientific replications can be conducted, and they reveal the benefits and challenges of crucial replication research. The organizers of this collection encourage scientists to reuse the data contained in the collection for their own work, and also believe that these replication examples can serve as educational resources for students, early-career researchers, and experienced scientists alike who are interested in learning more about the process of replication.

  18. CO2 Emissions from Fuel Combustion - 2012 Highlights

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-07-01

    How much CO2 are countries emitting? Where is it coming from? In the lead-up to the UN climate negotiations in Doha, the latest information on the level and growth of CO2 emissions, their source and geographic distribution will be essential to lay the foundation for a global agreement. To provide input to and support for the UN process the IEA is making available for free download the 'Highlights' version of CO2 Emissions from Fuel Combustion. This annual publication contains: estimates of CO2 emissions by country from 1971 to 2010; selected indicators such as CO2/GDP, CO2/capita, CO2/TPES and CO2/kWh; and CO2 emissions from international marine and aviation bunkers, and other relevant information.

  19. Wildlife studies on the Hanford Site: 1993 Highlights report

    Energy Technology Data Exchange (ETDEWEB)

    Cadwell, L.L. [ed.

    1994-04-01

    The Pacific Northwest Laboratory (PNL) Wildlife Resources Monitoring Project was initiated by DOE to track the status of wildlife populations to determine whether Hanford operations affected them. The project continues to conduct a census of wildlife populations that are highly visible, economically or aesthetically important, and rare or otherwise considered sensitive. Examples of long-term data collected and maintained through the Wildlife Resources Monitoring Project include annual goose nesting surveys conducted on islands in the Hanford Reach, wintering bald eagle surveys, and fall Chinook salmon redd (nest) surveys. The report highlights activities related to salmon and mollusks on the Hanford Reach of the Columbia River; describes efforts to map vegetation on the Site and efforts to survey species of concern; provides descriptions of shrub-steppe bird surveys, including bald eagles, Canada geese, and hawks; outlines efforts to monitor mule deer and elk populations on the Site; and describes development of a biological database management system.

  20. FY 1995 research highlights: PNL accomplishments in OER programs

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-10-01

    Pacific Northwest Laboratory (PNL) conducts fundamental and applied research in support of the US Department of Energy`s (DOE) core missions in science and technology, environmental quality, energy resources, and national security. Much of this research is funded by the program offices of DOE`s Office of Energy Research (DOE-ER), primarily the Office of Basic Energy Sciences (BES) and the Office of Health and Environmental Research (OHER), and by PNL`s Laboratory Directed Research and Development (LDRD) Program. This document is a collection of research highlights that describe PNL`s accomplishments in DOE-ER funded programs during Fiscal Year 1995. Included are accomplishments in research funded by OHER`s Analytical Technologies, Environmental Research, Health Effects, General Life Sciences, and Carbon Dioxide Research programs; BES`s Materials Science, Chemical Sciences, Engineering and Geoscience, and Applied Mathematical Sciences programs; and PNL`s LDRD Program. Summaries are given for 70 projects.

  1. Highlights of top quark cross-section measurements at ATLAS

    Directory of Open Access Journals (Sweden)

    Berta Peter

    2017-01-01

    Full Text Available The highlights of the measurements of top quark production in proton-proton collisions at the Large Hadron Collider with the ATLAS detector are presented. The inclusive measurements of the top-pair production cross section have reached high precision and are compared to the best available theoretical calculations. The differential cross section measurements, including results using boosted top quarks, probe our understanding of top-pair production in the TeV regime. The results are compared to Monte Carlo generators implementing LO and NLO matrix elements matched with parton showers. Measurements of the single top quark production cross section are presented in the t-channel and s-channel, and with associated production with a W boson. For the t-channel production, results on the ratio between top quark and antitop quark production cross sections and differential measurements are also included.

  2. Mobile learning and high-lighting language education

    DEFF Research Database (Denmark)

    Vinther, Jane

    advantage of the social side in their application. The aim has been to make language classes attractive and relevant and to highlight the attractiveness and fun in learning through web 2.0 and mobile units. The overall project was supported by the Danish ministry of education as well as the individual......-line and individually to assess the effect of the projects on student motivation and autonomy. The investigation throws light on personal experiences as well as the generally perceived image and status of foreign language learning in upper secondary school. The results of the study are not fully analysed at the present......Mobile learning and high-profiling language education. The number of students learning a second or foreign language and participating in instruction in languages other than English has been in decline for some time. There seems to be such a general tendency across nations albeit for a variety...

  3. Women in evolution - highlighting the changing face of evolutionary biology.

    Science.gov (United States)

    Wellenreuther, Maren; Otto, Sarah

    2016-01-01

    The face of science has changed. Women now feature alongside men at the forefront of many fields, and this is particularly true in evolutionary biology. This special issue celebrates the outstanding achievements and contributions of women in evolutionary biology, by highlighting a sample of their research and accomplishments. In addition to original research contributions, this collection of articles contains personal reflections to provide perspective and advice on succeeding as a woman in science. By showcasing the diversity and research excellence of women and drawing on their experiences, we wish to enhance the visibility of female scientists and provide inspiration as well as role models. These are exciting times for evolutionary biology, and the field is richer and stronger for the diversity of voices contributing to the field.

  4. Technology meets research 60 years of CERN technology : selected highlights

    CERN Document Server

    Taylor, Thomas; Treille, Daniel; Wenninger, Horst

    2017-01-01

    "Big" science and advanced technology are known to cross-fertilize. This book emphasizes the interplay between particle physics and technology at CERN that has led to breakthroughs in both research and technology over the laboratory's first 60 years. The innovations, often the work of individuals or by small teams, are illustrated with highlights describing selected technologies from the domains of accelerators and detectors. The book also presents the framework and conditions prevailing at CERN that enabled spectacular advances in technology and contributed to propel the European organization into the league of leading research laboratories in the world. While the book is specifically aimed at providing information for the technically interested general public, more expert readers may also appreciate the broad variety of subjects presented. Ample references are given for those who wish to further explore a given topic.

  5. SUPPORTING LEARNING THROUGH EPISTEMIC SCAFFOLDS EMBEDDED IN A HIGHLIGHTER TOOL

    Directory of Open Access Journals (Sweden)

    Jan Erik Dahl

    2016-11-01

    Full Text Available This article explores the use of epistemic scaffolds embedded in a digital highlighter tool that was used to support students’ readings and discussions of research articles. The use of annotation technologies in education is increasing, and annotations can play a wide variety of epistemic roles; e.g., they can facilitate a deeper level of engagement, support critical thinking, develop cognitive and metacognitive skills and introduce practices that can support knowledge building and independent learning. However, research has shown that the actual tool use often deviates from the underlying knowledge model in the tools. Hence, the situated and mediated nature of these tools is still poorly understood. Research also tends to study the tools as a passed on resource rather than being co-constructed between students and teachers. The researcher argues that approaching these resources as co-constructed can be more productive and can create new spaces for teacher–student dialogues, students’ agency and self-scaffolding.

  6. CO2 Emissions from Fuel Combustion 2011: Highlights

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-01

    How much CO2 are countries emitting? Where is it coming from? In the lead-up to the UN climate negotiations in Durban, the latest information on the level and growth of CO2 emissions, their source and geographic distribution will be essential to lay the foundation for a global agreement. To provide input to and support for the UN process the IEA is making available for free download the 'Highlights' version of CO2 Emissions from Fuel Combustion. This annual publication contains: - estimates of CO2 emissions by country from 1971 to 2009; - selected indicators such as CO2/GDP, CO2/capita, CO2/TPES and CO2/kWh; - CO2 emissions from international marine and aviation bunkers, and other relevant information. These estimates have been calculated using the IEA energy databases and the default methods and emission factors from the Revised 1996 IPCC Guidelines for National Greenhouse Gas Inventories.

  7. Highlights of top quark cross-section measurements at ATLAS

    CERN Document Server

    Berta, Peter; The ATLAS collaboration

    2017-01-01

    The highlights of the measurements of top quark production in proton-proton collisions at the Large Hadron Collider with the ATLAS detector are presented. The inclusive measurements of the top-pair production cross section have reached high precision and are compared to the best available theoretical calculations. The differential cross section measurements, including results using boosted top quarks, probe our understanding of top-pair production in the TeV regime. The results are compared to Monte Carlo generators implementing LO and NLO matrix elements matched with parton showers. Measurements of the single top quark production cross section are presented in the t-channel and s-channel, and with associated production with a W boson. For the t-channel production, results on the ratio between top quark and antitop quark production cross sections and differential measurements are also included.

  8. Ancient hyaenas highlight the old problem of estimating evolutionary rates.

    Science.gov (United States)

    Shapiro, Beth; Ho, Simon Y W

    2014-02-01

    Phylogenetic analyses of ancient DNA data can provide a timeline for evolutionary change even in the absence of fossils. The power to infer the evolutionary rate is, however, highly dependent on the number and age of samples, the information content of the sequence data and the demographic history of the sampled population. In this issue of Molecular Ecology, Sheng et al. (2014) analysed mitochondrial DNA sequences isolated from a combination of ancient and present-day hyaenas, including three Pleistocene samples from China. Using an evolutionary rate inferred from the ages of the ancient sequences, they recalibrated the timing of hyaena diversification and suggest a much more recent evolutionary history than was believed previously. Their results highlight the importance of accurately estimating the evolutionary rate when inferring timescales of geographical and evolutionary diversification. © 2013 John Wiley & Sons Ltd.

  9. The MeteoMet2 project—highlights and results

    Science.gov (United States)

    Merlone, A.; Sanna, F.; Beges, G.; Bell, S.; Beltramino, G.; Bojkovski, J.; Brunet, M.; del Campo, D.; Castrillo, A.; Chiodo, N.; Colli, M.; Coppa, G.; Cuccaro, R.; Dobre, M.; Drnovsek, J.; Ebert, V.; Fernicola, V.; Garcia-Benadí, A.; Garcia-Izquierdo, C.; Gardiner, T.; Georgin, E.; Gonzalez, A.; Groselj, D.; Heinonen, M.; Hernandez, S.; Högström, R.; Hudoklin, D.; Kalemci, M.; Kowal, A.; Lanza, L.; Miao, P.; Musacchio, C.; Nielsen, J.; Nogueras-Cervera, M.; Oguz Aytekin, S.; Pavlasek, P.; de Podesta, M.; Rasmussen, M. K.; del-Río-Fernández, J.; Rosso, L.; Sairanen, H.; Salminen, J.; Sestan, D.; Šindelářová, L.; Smorgon, D.; Sparasci, F.; Strnad, R.; Underwood, R.; Uytun, A.; Voldan, M.

    2018-02-01

    Launched in 2011 within the European Metrology Research Programme (EMRP) of EURAMET, the joint research project ‘MeteoMet’—Metrology for Meteorology—is the largest EMRP consortium; national metrology institutes, universities, meteorological and climate agencies, research institutes, collaborators and manufacturers are working together, developing new metrological techniques, as well as improving existing ones, for use in meteorological observations and climate records. The project focuses on humidity in the upper and surface atmosphere, air temperature, surface and deep-sea temperatures, soil moisture, salinity, permafrost temperature, precipitation, and the snow albedo effect on air temperature. All tasks are performed using a rigorous metrological approach and include the design and study of new sensors, new calibration facilities, the investigation of sensor characteristics, improved techniques for measurements of essential climate variables with uncertainty evaluation, traceability, laboratory proficiency and the inclusion of field influencing parameters, long-lasting measurements, and campaigns in remote and extreme areas. The vision for MeteoMet is to take a step further towards establishing full data comparability, coherency, consistency, and long-term continuity, through a comprehensive evaluation of the measurement uncertainties for the quantities involved in the global climate observing systems and the derived observations. The improvement in quality of essential climate variables records, through the inclusion of measurement uncertainty budgets, will also highlight possible strategies for the reduction of the uncertainty. This contribution presents selected highlights of the MeteoMet project and reviews the main ongoing activities, tasks and deliverables, with a view to its possible future evolution and extended impact.

  10. Acoustical Properties of Sediments.

    Science.gov (United States)

    1981-05-11

    SEDIMENT AS A FUNCTION OF GLYCERIN CONCENTRATION IN THE PORE FLUID AR LUT AS-S81430 DJS - GA 4-16-81 45 IWOo 6 I- 0 Ju w > 40 -- -OTHEORY oLEAST SQUARES...0024 Pot YrvtflU MSt4 INTO) LAIPY9 p 0639 62r4 96 ?4 LIIA A xflVrjl j 116 00639 62F6 25 0 E IIC) doP? )I- 17=1 W; T" [)1? 00640 62FS 20 1118 HWiA OIl ...TI1E’ 00IN iX? Oil A VGVSH 0)019 AV(’i rtj 0(1 A X70UI 0OJ1M XSCRCH l J (C *YSCRCH OnIlE X 3 0 1?2U NECF*LU b 1 ??) X K k’no Q ( 0 0 3. XOIlVM!) flj4

  11. Dating of sediments and determination of sedimentation rate. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Illus, E. [ed.

    1998-08-01

    The Second NKS (Nordic Nuclear Safety Research)/EKO-1 Seminar was held at the Finnish Centre for Radiation and Nuclear Safety (STUK) on April 2-3, 1997. The work of the NKS is based on 4-year programmes; the current programme having been planned for the years 1994-1997. The programme comprises 3 major fields, one of them being environmental effects (EKO). Under this umbrella there are 4 main projects. The EKO-1 project deals with marine radioecology, in particular bottom sediments and sediment processes. The programme of the second seminar consisted of 8 invited lecturers and 6 other scientific presentations. Dating of sediments and determination of sedimentation rate are important in all types of sedimentological study and model calculations of fluxes of substances in the aquatic environment. In many cases these tasks have been closely related to radioecological studies undertaken in marine and fresh water environments, because they are often based on measured depth profiles of certain natural or artificial radionuclides present in the sediments. During recent decades Pb-210 has proved to be very useful in dating of sediments, but some other radionuclides have also been successfully used, e.g. Pu-239,240, Am-241 and Cs-137. The difficulties existing and problems involved in dating of sediments, as well as solutions for resolving these problems are discussed in the presentations

  12. RESULTS OF SOLID PHASE SEDIMENT TOXICITY TESTS WITH REDUCED SEDIMENT VOLUMES FOR SEDIMENT TOXICITY

    Science.gov (United States)

    Development and standardization of sediment toxicity test methods for freshwater organisms have been underway for several years. Both EPA and ASTM have published methods for assessing the short-term (e.g., 10-d) toxicity of sediments to two benthic freshwater organisms (Hyalella ...

  13. Development and application of freshwater sediment-toxicity benchmarks for currently used pesticides

    Energy Technology Data Exchange (ETDEWEB)

    Nowell, Lisa H., E-mail: lhnowell@usgs.gov [U.S. Geological Survey, California Water Science Center, Placer Hall, 6000 J Street, Sacramento, CA 95819 (United States); Norman, Julia E., E-mail: jnorman@usgs.gov [U.S. Geological Survey, Oregon Water Science Center, 2130 SW 5" t" h Avenue, Portland, OR 97201 (United States); Ingersoll, Christopher G., E-mail: cingersoll@usgs.gov [U.S. Geological Survey, Columbia Environmental Research Center, 4200 New Haven Road, Columbia, MO 65021 (United States); Moran, Patrick W., E-mail: pwmoran@usgs.gov [U.S. Geological Survey, Washington Water Science Center, 934 Broadway, Suite 300, Tacoma, WA 98402 (United States)

    2016-04-15

    of sediment, and uncertainty in TEB values. Additional evaluations of benchmarks in relation to sediment chemistry and toxicity are ongoing. - Highlights: • Sediment-toxicity benchmarks are developed for 129 pesticides in whole sediment. • Benchmarks can be used to predict or interpret pesticide toxicity in whole sediment. • Benchmarks are based on spiked-sediment bioassays or equilibrium partitioning. • Benchmarks correctly predicted amphipod toxicity in 74% of samples in a case study. • Whole-sediment benchmarks may not always represent bioavailable concentrations.

  14. History highlights and future trends of infrared sensors

    Science.gov (United States)

    Corsi, Carlo

    2010-10-01

    Infrared (IR) technologies (materials, devices and systems) represent an area of excellence in science and technology and, even if they have been generally confined to a selected scientific community, they have achieved technological and scientific highlights constituting 'innovation drivers' for neighbouring disciplines, especially in the sensors field. The development of IR sensors, initially linked to astronomical observations, since World War II and for many years has been fostered essentially by defence applications, particularly thermo-vision and, later on, smart vision and detection, for surveillance and warning. Only in the last few decades, the impact of silicon technology has changed the development of IR detectors dramatically, with the advent of integrated signal read-outs and the opening of civilian markets (EO communications, biomedical, environmental, transport and energy applications). The history of infrared sensors contains examples of real breakthroughs, particularly true in the case of focal plane arrays that first appeared in the late 1970s, when the superiority of bi-dimensional arrays for most applications pushed the development of technologies providing the highest number of pixels. An impressive impulse was given to the development of FPA arrays by integration with charge coupled devices (CCD), with strong competition from different technologies (high-efficiency photon sensors, Schottky diodes, multi-quantum wells and, later on, room temperature microbolometers/cantilevers). This breakthrough allowed the development of high performance IR systems of small size, light weight and low cost - and therefore suitable for civil applications - thanks to the elimination of the mechanical scanning system and the progressive reduction of cooling requirements (up to the advent of microbolometers, capable of working at room temperature). In particular, the elimination of cryogenic cooling allowed the development and commercialisation of IR Smart Sensors

  15. Highlights lecture EANM 2015: the search for nuclear medicine's superheroes.

    Science.gov (United States)

    Buck, Andreas; Decristoforo, Clemens

    2016-09-01

    contributions focused on cardiac inflammation, cardiac sarcoidosis, and specific imaging of large vessel vasculitis. The physics and instrumentation track included many highlights such as novel, high resolution scanners. The most noteworthy news and developments of this meeting were summarized in the highlights lecture. Only 55 scientific contributions were mentioned, and hence they represent only a brief summary, which is outlined in this article. For a more detailed view, all presentations can be accessed by the online version of the European Journal of Nuclear Medicine and Molecular Imaging (Volume 42, Supplement 1).

  16. Highlighting Entanglement of Cultures via Ranking of Multilingual Wikipedia Articles

    Science.gov (United States)

    Eom, Young-Ho; Shepelyansky, Dima L.

    2013-01-01

    How different cultures evaluate a person? Is an important person in one culture is also important in the other culture? We address these questions via ranking of multilingual Wikipedia articles. With three ranking algorithms based on network structure of Wikipedia, we assign ranking to all articles in 9 multilingual editions of Wikipedia and investigate general ranking structure of PageRank, CheiRank and 2DRank. In particular, we focus on articles related to persons, identify top 30 persons for each rank among different editions and analyze distinctions of their distributions over activity fields such as politics, art, science, religion, sport for each edition. We find that local heroes are dominant but also global heroes exist and create an effective network representing entanglement of cultures. The Google matrix analysis of network of cultures shows signs of the Zipf law distribution. This approach allows to examine diversity and shared characteristics of knowledge organization between cultures. The developed computational, data driven approach highlights cultural interconnections in a new perspective. Dated: June 26, 2013 PMID:24098338

  17. Pre-accidental situations highlighted by RECUPERARE method and data

    Energy Technology Data Exchange (ETDEWEB)

    Matahri, N. [Institut de Radioprotection et de Surete Nucleaire (IRSN), 92 - Fontenay-aux-Roses (France)

    2006-07-01

    RECUPERARE method has been developed for operating feedback analysis and built on the French Human Reliability Analysis (HRA) principles. It is used to study the causes of human errors or technical failures occurred in French PWRs and the recovery process of events. Based on an event classification (6 categories) model according to the nature of the link between failure and recovery, the identified and recorded data are: the causes of the defects (technical, human, organizational) and the context in which they appear; the factors of the recovery performance (depending on technical and organizational aspects); a chronological analysis, designed to collect delays between failures and their detection/recovery for each event. About 3600 events reported in French PWRs (1997-2003) had been reviewed through this model. Initially, the weight of factors and the most important factors, which influenced the detection and recovery delay, are defined. For this purpose, the regression Partial Least Square (PLS) is used. Then, to link RECUPERARE results with pre-accidental data, conditional probabilities of events linked between them by a cause and effect relationship are calculated. For this, the Bayesian method with the Bayesian network is built with the PLS obtained results and applied. This constitutes a first approach to take into account in HRA the human and organizational factors highlighted by operating feedback. (author)

  18. Highlighting entanglement of cultures via ranking of multilingual Wikipedia articles.

    Directory of Open Access Journals (Sweden)

    Young-Ho Eom

    Full Text Available How different cultures evaluate a person? Is an important person in one culture is also important in the other culture? We address these questions via ranking of multilingual Wikipedia articles. With three ranking algorithms based on network structure of Wikipedia, we assign ranking to all articles in 9 multilingual editions of Wikipedia and investigate general ranking structure of PageRank, CheiRank and 2DRank. In particular, we focus on articles related to persons, identify top 30 persons for each rank among different editions and analyze distinctions of their distributions over activity fields such as politics, art, science, religion, sport for each edition. We find that local heroes are dominant but also global heroes exist and create an effective network representing entanglement of cultures. The Google matrix analysis of network of cultures shows signs of the Zipf law distribution. This approach allows to examine diversity and shared characteristics of knowledge organization between cultures. The developed computational, data driven approach highlights cultural interconnections in a new perspective. Dated: June 26, 2013.

  19. Highlighting entanglement of cultures via ranking of multilingual Wikipedia articles.

    Science.gov (United States)

    Eom, Young-Ho; Shepelyansky, Dima L

    2013-01-01

    How different cultures evaluate a person? Is an important person in one culture is also important in the other culture? We address these questions via ranking of multilingual Wikipedia articles. With three ranking algorithms based on network structure of Wikipedia, we assign ranking to all articles in 9 multilingual editions of Wikipedia and investigate general ranking structure of PageRank, CheiRank and 2DRank. In particular, we focus on articles related to persons, identify top 30 persons for each rank among different editions and analyze distinctions of their distributions over activity fields such as politics, art, science, religion, sport for each edition. We find that local heroes are dominant but also global heroes exist and create an effective network representing entanglement of cultures. The Google matrix analysis of network of cultures shows signs of the Zipf law distribution. This approach allows to examine diversity and shared characteristics of knowledge organization between cultures. The developed computational, data driven approach highlights cultural interconnections in a new perspective. Dated: June 26, 2013.

  20. Highlighting Interleukin-36 Signalling in Plaque Psoriasis and Pustular Psoriasis.

    Science.gov (United States)

    Furue, Kazuhisa; Yamamura, Kazuhiko; Tsuji, Gaku; Mitoma, Chikage; Uchi, Hiroshi; Nakahara, Takeshi; Kido-Nakahara, Makiko; Kadono, Takafumi; Furue, Masutaka

    2018-01-12

    Plaque psoriasis and pustular psoriasis are overlapping, but distinct, disorders. The therapeutic response to biologics supports the pivotal role of the tumour necrosis alpha (TNF-?)/ interleukin (IL)-23/IL-17/IL-22 axis in the pathogenesis of these disorders. Recently, functional activation of the IL-36 receptor (IL-36R) was discovered to be another driving force in the pathogenesis of psoriasis. This was first highlighted by the discovery that a loss-of-function mutation of the IL-36R antagonist (IL-36Ra) causes pustular psoriasis. Although the TNF-?/IL-23/IL-17/IL-22 axis and the functional activation of IL-36R are fundamentally involved in plaque psoriasis and pustular psoriasis, respectively, the 2 pathways are closely related and mutually reinforced, resulting in full-blown clinical manifestations. This review summarizes current topics on how IL-36 agonists (IL-36?, IL-36?, IL-36?) signal IL-36R, the pathological expression of IL-36 agonists and IL-36Ra in plaque and pustular psoriatic lesions, and the cross-talk between the TNF-?/IL-23/IL-17/IL-22 axis and the functional activation of IL-36R in the epidermal milieu.

  1. Satellite tracking of manta rays highlights challenges to their conservation.

    Directory of Open Access Journals (Sweden)

    Rachel T Graham

    Full Text Available We describe the real-time movements of the last of the marine mega-vertebrate taxa to be satellite tracked - the giant manta ray (or devil fish, Manta birostris, the world's largest ray at over 6 m disc width. Almost nothing is known about manta ray movements and their environmental preferences, making them one of the least understood of the marine mega-vertebrates. Red listed by the International Union for the Conservation of Nature as 'Vulnerable' to extinction, manta rays are known to be subject to direct and incidental capture and some populations are declining. Satellite-tracked manta rays associated with seasonal upwelling events and thermal fronts off the Yucatan peninsula, Mexico, and made short-range shuttling movements, foraging along and between them. The majority of locations were received from waters shallower than 50 m deep, representing thermally dynamic and productive waters. Manta rays remained in the Mexican Exclusive Economic Zone for the duration of tracking but only 12% of tracking locations were received from within Marine Protected Areas (MPAs. Our results on the spatio-temporal distribution of these enigmatic rays highlight opportunities and challenges to management efforts.

  2. Satellite tracking of manta rays highlights challenges to their conservation.

    Science.gov (United States)

    Graham, Rachel T; Witt, Matthew J; Castellanos, Dan W; Remolina, Francisco; Maxwell, Sara; Godley, Brendan J; Hawkes, Lucy A

    2012-01-01

    We describe the real-time movements of the last of the marine mega-vertebrate taxa to be satellite tracked - the giant manta ray (or devil fish, Manta birostris), the world's largest ray at over 6 m disc width. Almost nothing is known about manta ray movements and their environmental preferences, making them one of the least understood of the marine mega-vertebrates. Red listed by the International Union for the Conservation of Nature as 'Vulnerable' to extinction, manta rays are known to be subject to direct and incidental capture and some populations are declining. Satellite-tracked manta rays associated with seasonal upwelling events and thermal fronts off the Yucatan peninsula, Mexico, and made short-range shuttling movements, foraging along and between them. The majority of locations were received from waters shallower than 50 m deep, representing thermally dynamic and productive waters. Manta rays remained in the Mexican Exclusive Economic Zone for the duration of tracking but only 12% of tracking locations were received from within Marine Protected Areas (MPAs). Our results on the spatio-temporal distribution of these enigmatic rays highlight opportunities and challenges to management efforts.

  3. Highlights in peptide nanoparticle carriers intended to oral diseases.

    Science.gov (United States)

    Benergossi, Jéssica; Calixto, Giovana; Fonseca-Santos, Bruno; Aida, Kelly Limi; de Cássia Negrini, Thais; Duque, Cristiane; Gremião, Maria Palmira Daflon; Chorilli, Marlus

    2015-01-01

    New biocompatible nanomaterials are leading to a range of emerging health treatments. Thus, peptide drugs present in oral diseases, such as caries, periodontal diseases and oral cancer, are highlighting into clinical practice because the peptides can have an influence the growth of tumor cells or microorganisms and its can exhibit direct cytotoxic activity towards cancer cells or microbial cells. Therefore, it is interesting to speculate what are the natural or synthetic peptides that can be used to develop novel strategies to fight cancer diseases or microbial cells, and so, to represent a novel family of anticancer or antimicrobial agents. The use of buccal drug delivery systems, especially nanoparticles, to carrier peptides shows to be very interesting, because these systems can protect the peptide against enzymatic degradation, in addition to target inaccessible sites. However, this peptide delivery system seems to be unexplored by researchers. On the hand, the application of drug delivery systems for oral diseases could be a proposed treatment for these diseases, including the treatment or co-treatment with other therapies, such as photodynamic therapy, of antimicrobial, periodontal diseases and cancer, or even in the early diagnosis of cancer. The objective of this study is to present a systematic review of nanotechnology-based peptides delivery systems intended to oral diseases.

  4. Radio Astronomy at TIFR, some highlights and reminiscences

    Science.gov (United States)

    Swarup, G.

    Radio astronomy research was initiated at TIFR fifty years ago. In this historical article, I firstly trace my initiation in the field of radio astronomy during 1953-55 in the Radio Physics Laboratory of CSIRO in Australia and later during 1956-63 in USA. In September 1961, four radio astronomers working abroad wrote to a number of scientific organizations in India with their desire to start radio astronomy research in India. Soon thereafter Dr. Homi Bhabha, the founder Director of TIFR, approved the formation of a radio astronomy group therein. I joined TIFR in April 1963. During the last 50 years, TIFR has built two of the world's largest radio telescopes, namely the 530m long and 30 m wide parabolic cylinder equatorially mounted on a hill at Ooty in South India during 1960s and the Giant Metrewave Radio Telescope near Pune, consisting of 30 nos. of fully steerable parabolic dishes of 45 m diameters during 1990s. Fifty years of radio astronomy research at TIFR is briefly highlighted here.

  5. Wildlife studies on the Hanford site: 1994 Highlights report

    Energy Technology Data Exchange (ETDEWEB)

    Cadwell, L.L. [ed.

    1995-04-01

    The purposes of the project are to monitor and report trends in wildlife populations; conduct surveys to identify, record, and map populations of threatened, endangered, and sensitive plant and animal species; and cooperate with Washington State and federal and private agencies to help ensure the protection afforded by law to native species and their habitats. Census data and results of surveys and special study topics are shared freely among cooperating agencies. Special studies are also conducted as needed to provide additional information that may be required to assess, protect, or manage wildlife resources at Hanford. This report describes highlights of wildlife studies on the Site in 1994. Redd counts of fall chinook salmon in the Hanford Reach suggest that harvest restrictions directed at protecting Snake River salmon may have helped Columbia River stocks as well. The 1994 count (5619) was nearly double that of 1993 and about 63% of the 1989 high of approximately 9000. A habitat map showing major vegetation and land use cover types for the Hanford Site was completed in 1993. During 1994, stochastic simulation was used to estimate shrub characteristics (height, density, and canopy cover) across the previously mapped Hanford landscape. The information provided will be available for use in determining habitat quality for sensitive wildlife species. Mapping Site locations of plant species of concern continued during 1994. Additional sensitive plant species data from surveys conducted by TNC were archived. The 10 nesting pairs of ferruginous hawks that used the Hanford Site in 1993 represented approximately 25% of the Washington State population.

  6. Recent highlights from the PHENIX heavy ion program

    Directory of Open Access Journals (Sweden)

    Hill J.C.

    2015-01-01

    Full Text Available It is accepted that a QGP can be formed in relativistic collisions of heavy nuclei (A+A. Recently long-range correlations have been observed in p+A collisions at the LHC in high multiplicity events. PHENIX has carried out a series of studies of d+Au collisions at 200 GeV to see if such correlations persist at lower energies compared to those at the LHC. Results of a study of long-range correlations and flow are presented for d+Au collisions. Data from Au+Au collisions collected during the beam energy scan (BES was used to determine both quark and nucleon number scaling. The HBT method was used to determine radii of the fireball at kinetic freezeout. Implications for the nuclear EOS are discussed. Also results of a search for “dark photons” are presented. Recent PHENIX highlights on heavy flavor, electromagnetic probes, spin and plans for PHENIX upgrades were presented in other talks at this conference.

  7. Can Chimpanzee Biology Highlight Human Origin and Evolution?

    Science.gov (United States)

    Roffman, Itai; Nevo, Eviatar

    2010-01-01

    The closest living relatives of humans are their chimpanzee/bonobo (Pan) sister species, members of the same subfamily “Homininae”. This classification is supported by over 50 years of research in the fields of chimpanzee cultural diversity, language competency, genomics, anatomy, high cognition, psychology, society, self-consciousness and relation to others, tool use/production, as well as Homo level emotions, symbolic competency, memory recollection, complex multifaceted problem-solving capabilities, and interspecies communication. Language competence and symbolism can be continuously bridged from chimpanzee to man. Emotions, intercommunity aggression, body language, gestures, facial expressions, and vocalization of intonations seem to parallel between the sister taxa Homo and Pan. The shared suite of traits between Pan and Homo genus demonstrated in this article integrates old and new information on human–chimpanzee evolution, bilateral informational and cross-cultural exchange, promoting the urgent need for Pan cultures in the wild to be protected, as they are part of the cultural heritage of mankind. Also, we suggest that bonobos, Pan paniscus, based on shared traits with Australopithecus, need to be included in Australopithecine’s subgenus, and may even represent living-fossil Australopithecines. Unfolding bonobo and chimpanzee biology highlights our common genetic and cultural evolutionary origins. PMID:23908781

  8. AGILE DATA CENTER AT ASDC AND AGILE HIGHLIGHTS

    Directory of Open Access Journals (Sweden)

    Carlotta Pittori

    2013-12-01

    Full Text Available We present an overview of the main AGILE Data Center activities and the AGILE scientific highlights during the first 5 years of operations. AGILE is an ASI space mission in joint collaboration with INAF, INFN and CIFS, dedicated to the observation of the gamma-ray Universe. The AGILE satellite was launched on April 23rd, 2007, and is devoted to gamma-ray astrophysics in the 30MeV ÷ 50 GeV energy range, with simultaneous X-ray imaging capability in the 18 ÷ 60 keV band. Despite the small size and budget, AGILE has produced several important scientific results, including the unexpected discovery of strong and rapid gamma-ray flares from the Crab Nebula over daily timescales. This discovery won AGILE PI and the AGILE Team the prestigious Bruno Rossi Prize for 2012, an international award in the field of high energy astrophysics. Thanks to its sky monitoring capability and fast ground segment alert system, AGILE is substantially improving our knowledge of the gamma-ray sky, also making a crucial contribution to the study of the terrestrial gamma-ray flashes (TGFs detected in the Earth atmosphere. The AGILE Data Center, part of the ASI Science Data Center (ASDC located in Frascati, Italy, is in charge of all the science oriented activities related to the analysis, archiving and distribution of AGILE data.

  9. Can Chimpanzee Biology Highlight Human Origin and Evolution?

    Directory of Open Access Journals (Sweden)

    Itai Roffman

    2010-07-01

    Full Text Available The closest living relatives of humans are their chimpanzee/bonobo (Pan sister species, members of the same subfamily “Homininae”. This classification is supported by over 50 years of research in the fields of chimpanzee cultural diversity, language competency, genomics, anatomy, high cognition, psychology, society, self-consciousness and relation to others, tool use/production, as well as Homo level emotions, symbolic competency, memory recollection, complex multifaceted problem-solving capabilities, and interspecies communication. Language competence and symbolism can be continuously bridged from chimpanzee to man. Emotions, intercommunity aggression, body language, gestures, facial expressions, and vocalization of intonations seem to parallel between the sister taxa Homo and Pan. The shared suite of traits between Pan and Homo genus demonstrated in this article integrates old and new information on human–chimpanzee evolution, bilateral informational and cross-cultural exchange, promoting the urgent need for Pan cultures in the wild to be protected, as they are part of the cultural heritage of mankind. Also, we suggest that bonobos, Pan paniscus, based on shared traits with Australopithecus, need to be included in Australopithecine’s subgenus, and may even represent living-fossil Australopithecines. Unfolding bonobo and chimpanzee biology highlights our common genetic and cultural evolutionary origins.

  10. Highlights on Hevea brasiliensis (pro)hevein proteins.

    Science.gov (United States)

    Berthelot, Karine; Peruch, Frédéric; Lecomte, Sophie

    2016-08-01

    Hevein, from Hevea brasiliensis (rubber tree), was identified in 1960. It is the most abundant soluble protein (22%) found in latex. Hevein is formed from a larger protein called prohevein. The 187 amino-acid prohevein is cleaved into two fragments: the N-terminal 43 amino-acid hevein, a lectin bearing a chitin-binding motif with antifungal properties, and a C-terminal domain (C-ter), which possesses amyloid properties. Hevein-like proteins are also widely represented in the plant kingdom and belong to a larger family related to stress and pathogenic responses. During the last 55 years, these proteins have attracted the interest of numerous specialists from the fields of plant physiology, genetics, molecular and structural biology, and physico-chemistry to allergology. This review highlights various aspects of hevein, prohevein, and C-ter from the point of view of these various fields, and examines their potential roles in latex as well as their beneficial and negative biological effects (e.g. wound sealing and resistance to pathogens which is mediated by agglutination, antimicrobial activity, and/or allergenicity). It covers results and observations from 1960 up to the most recent research. Copyright © 2016 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.

  11. Research highlights: microfluidic-enabled single-cell epigenetics.

    Science.gov (United States)

    Dhar, Manjima; Khojah, Reem; Tay, Andy; Di Carlo, Dino

    2015-11-07

    Individual cells are the fundamental unit of life with diverse functions from metabolism to motility. In multicellular organisms, a single genome can give rise to tremendous variability across tissues at the single-cell level due to epigenetic differences in the genes that are expressed. Signals from the local environment or a history of signals can drive these variations, and tissues have many cell types that play separate roles. This epigenetic heterogeneity is of biological importance in normal functions such as tissue morphogenesis and can contribute to development or resistance of cancer, or other disease states. Therefore, an improved understanding of variations at the single cell level are fundamental to understanding biology and developing new approaches to combating disease. Traditional approaches to characterize epigenetic modifications of chromatin or the transcriptome of cells have often focused on blended responses of many cells in a tissue; however, such bulk measures lose spatial and temporal differences that occur from cell to cell, and cannot uncover novel or rare populations of cells. Here we highlight a flurry of recent activity to identify the mRNA profiles from thousands of single-cells as well as chromatin accessibility and histone marks on single to few hundreds of cells. Microfluidics and microfabrication have played a central role in the range of new techniques, and will likely continue to impact their further development towards routine single-cell epigenetic analysis.

  12. Highlights of the advances in basic immunology in 2011.

    Science.gov (United States)

    Liu, Juan; Liu, Shuxun; Cao, Xuetao

    2012-05-01

    In this review, we summarize the major fundamental advances in immunological research reported in 2011. The highlights focus on the improved understanding of key questions in basic immunology, including the initiation and activation of innate responses as well as mechanisms for the development and function of various T-cell subsets. The research includes the identification of novel cytosolic RNA and DNA sensors as well as the identification of the novel regulators of the Toll-like receptor (TLR) and retinoic acid-inducible gene I (RIG-I)-like receptor (RLR) signaling pathway. Moreover, remarkable advances have been made in the developmental and functional properties of innate lymphoid cells (ILCs). Helper T cells and regulatory T (Treg) cells play indispensable roles in orchestrating adaptive immunity. There have been exciting discoveries regarding the regulatory mechanisms of the development of distinct T-cell subsets, particularly Th17 cells and Treg cells. The emerging roles of microRNAs (miRNAs) in T cell immunity are discussed, as is the recent identification of a novel T-cell subset referred to as follicular regulatory T (TFR) cells.

  13. Coastal sediment dynamics in Spitsbergen

    Science.gov (United States)

    Deloffre, J.; Lafite, R.; Baltzer, A.; Marlin, C.; Delangle, E.; Dethleff, D.; Petit, F.

    2010-12-01

    In arctic knowledge on coastal sediment dynamics and sedimentary processes is limited. The studied area is located in the microtidal Kongsfjorden glacial fjord on the North-western coast of Spitsbergen in the Artic Ocean (79°N). In this area sediment contributions to the coastal zone is provided by small temporary rivers that flows into the fjord. The objectives of this study are to (i) assess the origin and fate of fine-grained particles (ice cover on sediment dynamics. The sampling strategy is based on characterization of sediment and SPM (grain-size, X-rays diffraction, SEM images, carbonates and organic matter contents) from the glacier to the coastal zone completed by a bottom-sediment map on the nearshore using side-scan sonar validated with Ekman binge sampling. River inputs (i.e. river plumes) to the coastal zone were punctually followed using CTD (conductivity, temperature, depth and turbidity) profiles. OBS (water level, temperature and turbidity) operating at high-frequency and during at least 1 years (including under sea ice cover) was settled at the mouth of rivers at 10m depth. In the coastal zone the fine-grained sediment deposit is limited to mud patches located at river mouths that originate the piedmont glacier. However a significant amount of sediment originates the coastal glacier located in the eastern part of the fjord via two processes: direct transfer and ice-drop. Results from turbidity measurements show that the sediment dynamics is controlled by river inputs in particular during melting period. During winter sediment resuspension can occurs directly linked to significant wind-events. When the sea ice cover is present (January to April) no sediment dynamics is observed. Sediment processes in the coastal zone of arctic fjords is significant however only a small amount of SPM that originates the river plume settles in the coastal zone; only the coarser material settles at the mouth of the river while the finer one is deposited further (in

  14. SEDIMENTATION BROKEN IN INCLINED SEOIMENTADORES

    OpenAIRE

    Lama-Ramirez, R.; Facultad de Química e Ingeniería Química, Departamento Académico de Operaciones Unitarias,Universidad Nacional Mayor de San Marcos,Lima,Perú.; Condorhuamán-Ccorimanya, C.; Facultad de Química e Ingeniería Química, Departamento Académico de Operaciones Unitarias,Universidad Nacional Mayor de San Marcos,Lima,Perú.

    2014-01-01

    We have studied the batch sedimentation of aqueous suspensions of precipitated calcium carbonate, barium sulfate and lead oxide settlers inclined rectangular and circular cross section. The énguio tilt with respect to the horizontal between 35 ° and 75 °, to suspensions that vary in strength between 39.4 and 1070 g / l.Las obtained apparent sedimentation velocities ranging from 0.071 to 17.6 cm / min. the apparent sedimentation rate has been correlated using a modified version of the equation...

  15. ESA `Huygens and Mars Express' science highlights - call to press

    Science.gov (United States)

    2005-11-01

    Almost one year has passed since ESA’s Huygens probe landed on Saturn’s largest moon, Titan. Today, a set of new wide-ranging results from the probe’s two-and-a-half hour descent and landing, part of the extraordinary NASA/ESA/ASI Cassini-Huygens mission to Saturn and its moons, is ready for release. At the same time, ESA’s Mars Express mission is continuing its investigations of Mars, painting a new picture of the 'red planet'. This includes the first ever probing below the surface of Mars, new geological clues with implications for the climate, newly-discovered surface and atmospheric features and, above all, traces of the presence of water on this world. These and other exciting findings from just one year of observations and data analysis - in the context of ESA’s overall scientific achievements - will be the focus of a press conference to be held at ESA Headquarters in Paris at 16:00 on 30 November 2005. Media interested in attending are invited to complete the following registration form. Press conference programme Space Science Highlights 2005 From Huygens to Mars Express 30 November 2005, 16:00 hrs Room 137, European Space Agency Headquarters 8-10 Rue Mario-Nikis, F-75738 Paris Cedex, France 15:30 - Registration 16:00 - A Year of European Space Science Successes Prof. David Southwood, ESA Director of Science Programme 16:10 - Highlights of the Huygens Mission Results Jean-Pierre Lebreton, ESA Huygens Project Scientist 16:15 - Robin Duttaroy, Co-Investigator, Doppler Wind Experiment, University of Bonn, Germany 16:20 - Marcello Fulchignoni , Principal Investigator, Huygens Atmospheric Structure Instrument, Université de Paris 7, France 16:25 - John Zarnecki, Principal Investigator, Surface Science Package, Open University, UK 16:30 - François Raulin, Co-Investigator, Gas Chromatograph Mass Spectrometer, Université de Paris 12 - Créteil, France 16:35 - Guy Israel, Principal Investigator, Aerosol Collector and Pyrolyser, Service d

  16. Highlights from Hitomi observations of non-Perseus targets

    Science.gov (United States)

    Yamaguchi, Hiroya; Bamba, Aya; Ishida, Manabu; Katsuda, Satoru; Hughes, John Patrick; Madejski, Greg; Fukazawa, Yasushi; Hitomi Collaboration

    2017-01-01

    Before the tragic loss of the spacecraft due to attitude control problems, Hitomi observed three supernova remnants (SNR), N132D, G21.5-0.9, and the Crab Nebula, with the main purpose of initial in-orbit calibration. Here we present some scientific highlights of these observations.N132D is a middle-aged, core-collapse SNR in the Large Magellanic Cloud (LMC). It was observed after the Perseus cluster. Even though the exposure was very short, the SXS clearly resolves the fine structure of He-like S K-shell emission. We detect a significant redshift that is consistent with the line-of-sight velocity of the LMC. Fe K emission is redshifted even more significantly, with a corresponding velocity of ~2000 km/s. This suggests a non-uniform velocity distribution of the Fe ejecta, probably due to an asymmetric supernova explosion.G21.5-0.9 is a young plerionic composite-type SNR. Powered by the 62 ms rotation-powered pulsar J1833-1034, the SNR is dominated by non-thermal emission from the pulsar wind nebula, with extended limb-brightening and knots of X-ray emission. The Hitomi SXS, SXI, and HXI observations provide a high-statistics wide-band spectrum from a single satellite. We are currently searching for 1) emission or absorption line features, 2) a spectral break in the continuum, and 3) the pulse period. The status of the analysis and results will be presented.The Crab was observed after all the instruments aboard Hitomi were turned on. We successfully obtain the pulse profile with all of the instruments. The X-ray polarization is being studied with the HXI and SGD. We also search for emission/absorption lines with the SXS, but no features have so far been significantly detected. We discuss the results in light of constraining the nature of the Crab's progenitor explosion.

  17. Overview of NSTX Upgrade initial results and modelling highlights

    Science.gov (United States)

    Menard, J. E.; Allain, J. P.; Battaglia, D. J.; Bedoya, F.; Bell, R. E.; Belova, E.; Berkery, J. W.; Boyer, M. D.; Crocker, N.; Diallo, A.; Ebrahimi, F.; Ferraro, N.; Fredrickson, E.; Frerichs, H.; Gerhardt, S.; Gorelenkov, N.; Guttenfelder, W.; Heidbrink, W.; Kaita, R.; Kaye, S. M.; Kriete, D. M.; Kubota, S.; LeBlanc, B. P.; Liu, D.; Lunsford, R.; Mueller, D.; Myers, C. E.; Ono, M.; Park, J.-K.; Podesta, M.; Raman, R.; Reinke, M.; Ren, Y.; Sabbagh, S. A.; Schmitz, O.; Scotti, F.; Sechrest, Y.; Skinner, C. H.; Smith, D. R.; Soukhanovskii, V.; Stoltzfus-Dueck, T.; Yuh, H.; Wang, Z.; Waters, I.; Ahn, J.-W.; Andre, R.; Barchfeld, R.; Beiersdorfer, P.; Bertelli, N.; Bhattacharjee, A.; Brennan, D.; Buttery, R.; Capece, A.; Canal, G.; Canik, J.; Chang, C. S.; Darrow, D.; Delgado-Aparicio, L.; Domier, C.; Ethier, S.; Evans, T.; Ferron, J.; Finkenthal, M.; Fonck, R.; Gan, K.; Gates, D.; Goumiri, I.; Gray, T.; Hosea, J.; Humphreys, D.; Jarboe, T.; Jardin, S.; Jaworski, M. A.; Koel, B.; Kolemen, E.; Ku, S.; La Haye, R. J.; Levinton, F.; Luhmann, N.; Maingi, R.; Maqueda, R.; McKee, G.; Meier, E.; Myra, J.; Perkins, R.; Poli, F.; Rhodes, T.; Riquezes, J.; Rowley, C.; Russell, D.; Schuster, E.; Stratton, B.; Stutman, D.; Taylor, G.; Tritz, K.; Wang, W.; Wirth, B.; Zweben, S. J.

    2017-10-01

    The National Spherical Torus Experiment (NSTX) has undergone a major upgrade, and the NSTX Upgrade (NSTX-U) Project was completed in the summer of 2015. NSTX-U first plasma was subsequently achieved, diagnostic and control systems have been commissioned, the H-mode accessed, magnetic error fields identified and mitigated, and the first physics research campaign carried out. During ten run weeks of operation, NSTX-U surpassed NSTX record pulse-durations and toroidal fields (TF), and high-performance ~1 MA H-mode plasmas comparable to the best of NSTX have been sustained near and slightly above the n  =  1 no-wall stability limit and with H-mode confinement multiplier H98y,2 above 1. Transport and turbulence studies in L-mode plasmas have identified the coexistence of at least two ion-gyro-scale turbulent micro-instabilities near the same radial location but propagating in opposite (i.e. ion and electron diamagnetic) directions. These modes have the characteristics of ion-temperature gradient and micro-tearing modes, respectively, and the role of these modes in contributing to thermal transport is under active investigation. The new second more tangential neutral beam injection was observed to significantly modify the stability of two types of Alfven eigenmodes. Improvements in offline disruption forecasting were made in the areas of identification of rotating MHD modes and other macroscopic instabilities using the disruption event characterization and forecasting code. Lastly, the materials analysis and particle probe was utilized on NSTX-U for the first time and enabled assessments of the correlation between boronized wall conditions and plasma performance. These and other highlights from the first run campaign of NSTX-U are described.

  18. Structure-activity relationship of nerve-highlighting fluorophores.

    Directory of Open Access Journals (Sweden)

    Summer L Gibbs

    Full Text Available Nerve damage is a major morbidity associated with numerous surgical interventions. Yet, nerve visualization continues to challenge even the most experienced surgeons. A nerve-specific fluorescent contrast agent, especially one with near-infrared (NIR absorption and emission, would be of immediate benefit to patients and surgeons. Currently, there are only three classes of small molecule organic fluorophores that penetrate the blood nerve barrier and bind to nerve tissue when administered systemically. Of these three classes, the distyrylbenzenes (DSBs are particularly attractive for further study. Although not presently in the NIR range, DSB fluorophores highlight all nerve tissue in mice, rats, and pigs after intravenous administration. The purpose of the current study was to define the pharmacophore responsible for nerve-specific uptake and retention, which would enable future molecules to be optimized for NIR optical properties. Structural analogs of the DSB class of small molecules were synthesized using combinatorial solid phase synthesis and commercially available building blocks, which yielded more than 200 unique DSB fluorophores. The nerve-specific properties of all DSB analogs were quantified using an ex vivo nerve-specific fluorescence assay on pig and human sciatic nerve. Results were used to perform quantitative structure-activity relationship (QSAR modeling and to define the nerve-specific pharmacophore. All DSB analogs with positive ex vivo fluorescence were tested for in vivo nerve specificity in mice to assess the effect of biodistribution and clearance on nerve fluorescence signal. Two new DSB fluorophores with the highest nerve to muscle ratio were tested in pigs to confirm scalability.

  19. Students' reflections in a portfolio pilot: highlighting professional issues.

    Science.gov (United States)

    Haffling, Ann-Christin; Beckman, Anders; Pahlmblad, Annika; Edgren, Gudrun

    2010-01-01

    Portfolios are highlighted as potential assessment tools for professional competence. Although students' self-reflections are considered to be central in the portfolio, the content of reflections in practice-based portfolios is seldom analysed. To investigate whether students' reflections include sufficient dimensions of professional competence, notwithstanding a standardized portfolio format, and to evaluate students' satisfaction with the portfolio. Thirty-five voluntary final-year medical students piloted a standardized portfolio in a general practice (GP) attachment at Lund University, Sweden. Students' portfolio reflections were based upon documentary evidence from practice, and aimed to demonstrate students' learning. The reflections were qualitatively analysed, using a framework approach. Students' evaluations of the portfolio were subjected to quantitative and qualitative analysis. Among professional issues, an integration of cognitive, affective and practical dimensions in clinical practice was provided by students' reflections. The findings suggested an emphasis on affective issues, particularly on self-awareness of feelings, attitudes and concerns. In addition, ethical problems, clinical reasoning strategies and future communication skills training were subjects of several reflective commentaries. Students' reflections on their consultation skills demonstrated their endeavour to achieve structure in the medical interview by negotiation of an agenda for the consultation, keeping the interview on track, and using internal summarizing. The importance of active listening and exploration of patient's perspective was also emphasized. In students' case summaries, illustrating characteristic attributes of GP, the dominating theme was 'patient-centred care', including the patient-doctor relationship, holistic modelling and longitudinal continuity. Students were satisfied with the portfolio, but improved instructions were needed. A standardized portfolio in a

  20. BRITICE-CHRONO: The project and highlights so far

    Science.gov (United States)

    Fabel, D.; Clark, C.; Chiverrell, R. C.; O'Cofaigh, C.; Scourse, J. D.; Hindmarsh, R. C. A.

    2015-12-01

    BRITICE-CHRONO is a five-year Natural Environment Research Council (NERC) funded consortium of more than 40 researchers comprising glaciologists, marine and terrestrial Quaternary scientists and ice sheet-modellers, with the specific aim to systematically collect and date material to constrain the timing and rates of change of the marine-influenced sectors of the collapsing British Irish Ice Sheet (http://britice-chrono.org/). At the halfway point of the project we have completed two 40-day research cruises circumnavigating the British Isles and Ireland, and over 300 person-days of terrestrial fieldwork, yieldeding around 15 tonnes of samples for dating by optically stimulated luminescence-, surface exposure-, and radiocarbon methods. By March 2016 we expect to have generated about 850 new dates from landforms associated with the deglaciation of the last British and Irish ice-sheet. The success of the project will in part depend on the team being able to provide ice-sheet modellers with robust chronological markers against which the ice-sheet models can be tested. The decision-making process in deciding robustness of ages derived from multiple samples and different Quaternary geochronological methods will be discussed. Some geochronological highlights thus far are that deglaciation of the northwest sector of the ice-sheet was in progress at 28ka, well before the global LGM, and the northern tip of mainland Scotland was ice free by 25ka. At the same time the Irish Sea ice stream in the south appears to have been advancing towards its maximum extend. Although deglaciation in the south commences much later, both the main southern and northern ice streams appear to have persisted for at least 10ka with final retreat onto the mainland occurring at approximately the same time (16ka).

  1. Inertial Screening in Sedimentation

    Science.gov (United States)

    Segre, P. N.; Curreri, Peter A. (Technical Monitor)

    2001-01-01

    Using particle image velocimetry we have measured the sedimentation dynamics of non-Brownian spheres over a wide range of Reynolds numbers (Re) between 0.001 and 2.5. Particle velocity fluctuations about the mean settling velocity show large-scale correlations whose spatial extent and magnitude Delta V/V are independent of Re up to a critical value Re less than Re(sub c). For Re greater than Re(sub c) the fluctuations substantially diminish with increasing Reynolds number due to inertial screening of the long-range hydrodynamic interactions (HI). The onset of inertial affects is found to occur when the Oseen length l(sub o)=v/V becomes of order the correlation length. In the inertial regime, the velocity fluctuations follow -(Delta V/V)(sup 2) approaching ln(Re), in agreement with an integration of the (l/r) HI over a narrow region extending up to the Oseen length l(sub o). A simple "blob" model connects the measured correlation lengths to the magnitudes of the velocity fluctuations.

  2. Haw River sediment quality assessment

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report documents an evaluation of chemical contaminants in, and toxicity of, sediments collected from impoundments created by dams on the Haw River in Alamance...

  3. Cable Bacteria in Freshwater Sediments

    DEFF Research Database (Denmark)

    Risgaard-Petersen, Nils; Kristiansen, Michael; Frederiksen, Rasmus

    2015-01-01

    In marine sediments cathodic oxygen reduction at the sediment surface can be coupled to anodic sulfide oxidation in deeper anoxic layers through electrical currents mediated by filamentous, multicellular bacteria of the Desulfobulbaceae family, the so-called cable bacteria. Until now, cable...... bacteria have only been reported from marine environments. In this study, we demonstrate that cable bacteria also occur in freshwater sediments. In a first step, homogenized sediment collected from the freshwater stream Giber Å, Denmark, was incubated in the laboratory. After 2 weeks, pH signatures...... marine cable bacteria, with the genus Desulfobulbus as the closest cultured lineage. The results of the present study indicate that electric currents mediated by cable bacteria could be important for the biogeochemistry in many more environments than anticipated thus far and suggest a common evolutionary...

  4. Hydrodynamic separator sediment retention testing.

    Science.gov (United States)

    2010-03-01

    Hydrodynamic separators are widely used in urban areas for removal of suspended sediments and floatables from : stormwater due to limited land availability for the installation of above ground stormwater best management : practices (BMPs). Hydrodynam...

  5. Kanawha River Basin Sediment Data

    Data.gov (United States)

    U.S. Environmental Protection Agency — This data set contains sediment size data collected at research sites using a Wolman Pebble Count method. This dataset is associated with the following publication:...

  6. The microbial nitrogen cycling potential in marine sediments is impacted by polyaromatic hydrocarbon pollution

    Directory of Open Access Journals (Sweden)

    Nicole M Scott

    2014-03-01

    Full Text Available During petroleum hydrocarbon exposure the composition and functional dynamics of marine microbial communities are altered, favoring bacteria that can utilize this rich carbon source. Initial exposure of high levels of hydrocarbons in aerobic surface sediments can enrich growth of heterotrophic microorganisms having hydrocarbon degradation capacity. As a result, there can be a localized reduction in oxygen potential, if the sediments are aerobic, within the surface layer of marine sediments resulting in anaerobic zones. We hypothesized that increasing exposure to elevated hydrocarbon concentrations would positively correlate with an increase in denitrification processes and the net accumulation of dinitrogen. This hypothesis was tested by comparing the relative abundance of genes associated with nitrogen metabolism and nitrogen cycling identified in 6 metagenomes from sediments contaminated by polyaromatic hydrocarbons from the Deepwater Horizon oil spill in the Gulf of Mexico, and 3 metagenomes from sediments associated with natural oil seeps in the Santa Barbara Channel. An additional 8 metagenomes from uncontaminated sediments from the Gulf of Mexico were analyzed for comparison. We predicted relative changes in metabolite turnover as a function of the differential microbial gene abundances, which showed predicted accumulation of metabolites associated with denitrification processes, including anammox, in the contaminated samples compared to uncontaminated sediments, with the magnitude of this change being positively correlated to the hydrocarbon concentration and exposure duration. These data highlight the potential impact of hydrocarbon inputs on N cycling processes in marine sediments and provide information relevant for system scale models of nitrogen metabolism in affected ecosystems.

  7. Influence of Wastewater Discharge on the Metabolic Potential of the Microbial Community in River Sediments

    KAUST Repository

    Li, Dong

    2015-09-24

    To reveal the variation of microbial community functions during water filtration process in river sediments, which has been utilized widely in natural water treatment systems, this study investigates the influence of municipal wastewater discharge to streams on the phylotype and metabolic potential of the microbiome in upstream and particularly various depths of downstream river sediments. Cluster analyses based on both microbial phylogenetic and functional data collectively revealed that shallow upstream sediments grouped with those from deeper subsurface downstream regions. These sediment samples were distinct from those found in shallow downstream sediments. Functional genes associated with carbohydrate, xenobiotic, and certain amino acid metabolisms were overrepresented in upstream and deep downstream samples. In contrast, the more immediate contact with wastewater discharge in shallow downstream samples resulted in an increase in the relative abundance of genes associated with nitrogen, sulfur, purine and pyrimidine metabolisms, as well as restriction–modification systems. More diverse bacterial phyla were associated with upstream and deep downstream sediments, mainly including Actinobacteria, Planctomycetes, and Firmicutes. In contrast, in shallow downstream sediments, genera affiliated with Betaproteobacteria and Gammaproteobacteria were enriched with putative functions that included ammonia and sulfur oxidation, polyphosphate accumulation, and methylotrophic bacteria. Collectively, these results highlight the enhanced capabilities of microbial communities residing in deeper stream sediments for the transformation of water contaminants and thus provide a foundation for better design of natural water treatment systems to further improve the removal of contaminants. © 2015, Springer Science+Business Media New York.

  8. Gravitational sedimentation of gold nanoparticles.

    Science.gov (United States)

    Alexander, Colleen M; Dabrowiak, James C; Goodisman, Jerry

    2013-04-15

    We study the gravitational sedimentation of citrate- or ascorbate-capped spherical gold nanoparticles (AuNP) by measuring the absorption-vs.-time curve produced as the particles sediment through the optical beam of a spectrophotometer, and comparing the results with a calculated sedimentation curve. TEM showed the AuNP had gold-core diameters of 12.1±0.6, 65.0±5.2, 82.5±5.2 or 91.8±6.2 nm, and gave diameter distribution histograms. The Mason-Weaver sedimentation-diffusion equation was solved for various particle diameters and the solutions were weighted with the TEM histogram and the size-dependent extinction coefficient, for comparison with absorbance-vs.-time curve obtained from freshly prepared suspensions of the AuNP. For particles having average gold-core diameters of 12.1±0.6, 65.0±5.2 and 82.5±5.2 nm, very good agreement exists between the theoretical and observed curves, showing that the particles sediment individually and that the diameter of the gold core is the important factor controlling sedimentation. For the largest particles, observed and calculated curves generally agree, but the former shows random effects consistent with non-homogeneous domains in the sample. Unlike TEM, the simple and unambiguous sedimentation experiment detects all the particles in the sample and can in principle be used to derive the true size histogram. It avoids artifacts of TEM sampling and shear forces of ultracentrifugation. We also show how information about the size histogram can be obtained from the sedimentation curve. Copyright © 2013 Elsevier Inc. All rights reserved.

  9. Sediment Transport by Turbidity Currents

    OpenAIRE

    Winslow, Kyle T.

    2001-01-01

    Complete field equations have been established for turbidity current flow. A Modified Three Equation Model has been developed to predict the fate of turbidity currents. Particular attention has focused on the impacts of increased sediment concentration on the field equations and the numerical predictions. Functional relationships for closure hypotheses have been chosen after careful review. Previous investigations have invoked the dilute suspension approximation for sediment concent...

  10. Mathematical theory of sedimentation analysis

    CERN Document Server

    Fujita, Hiroshi; Van Rysselberghe, P

    1962-01-01

    Mathematical Theory of Sedimentation Analysis presents the flow equations for the ultracentrifuge. This book is organized into two parts encompassing six chapters that evaluate the systems of reacting components, the differential equations for the ultracentrifuge, and the case of negligible diffusion. The first chapters consider the Archibald method for molecular weight determination; pressure-dependent sedimentation; expressions for the refractive index and its gradient; relation between refractive index and concentration; and the analysis of Gaussian distribution. Other chapters deal with th

  11. Testing lagoonal sediments with early life stages of the copepod Acartia tonsa (Dana): An approach to assess sediment toxicity in the Venice Lagoon.

    Science.gov (United States)

    Picone, Marco; Bergamin, Martina; Delaney, Eugenia; Ghirardini, Annamaria Volpi; Kusk, Kresten Ole

    2018-01-01

    The early-life stages of development of the calanoid copepod Acartia tonsa from egg to copepodite I is proposed as an endpoint for assessing sediment toxicity by exposing newly released eggs directly onto the sediment-water interface. A preliminary study of 5 sediment samples collected in the lagoon of Venice highlighted that the larval development rate (LDR) and the early-life stages (ELS) mortality endpoints with A. tonsa are more sensitive than the standard amphipod mortality test; moreover LDR resulted in a more reliable endpoint than ELS mortality, due to the interference of the sediment with the recovery of unhatched eggs and dead larvae. The LDR data collected in a definitive study of 48 sediment samples from the Venice Lagoon has been analysed together with the preliminary data to evaluate the statistical performances of the bioassay (among replicate variance and minimum significant difference between samples and control) and to investigate the possible correlation with sediment chemistry and physical properties. The results showed that statistical performances of the LDR test with A. tonsa correspond with the outcomes of other tests applied to the sediment-water interface (Strongylocentrotus purpuratus embryotoxicity test), sediments (Neanthes arenaceodentata survival and growth test) and porewater (S. purpuratus); the LDR endpoint did, however, show a slightly higher variance as compared with other tests used in the Lagoon of Venice, such as 10-d amphipod lethality test and larval development with sea urchin and bivalves embryos. Sediment toxicity data highlighted the high sensitivity and the clear ability of the larval development to discriminate among sediments characterized by different levels of contamination. The data of the definitive study evidenced that inhibition of the larval development was not affected by grain-size and the organic carbon content of the sediment; in contrast, a strong correlation between inhibition of the larval development

  12. Fluvial bar dynamics in large meandering rivers with different sediment supply in the Amazon River basin

    Science.gov (United States)

    Monegaglia, Federico; Zolezzi, Guido; Tubino, Marco; Henshaw, Alex

    2017-04-01

    Sediments in the large meandering rivers of the Amazon basin are known to be supplied by sources providing highly different magnitudes of sediment input and storage, ranging from the sediment-rich Andean region to the sediment-poor Central Trough. Recent observations have highlighted how such differences in sediment supply have an important, net effect on the rates of planform activity of meandering rivers in the basin, in terms of meander migration and frequency of cutoffs. In this work we quantify and discuss the effect of sediment supply on the organization of macroscale sediment bedforms on several large meandering rivers in the Amazon basin, and we link our findings with those regarding the rates of planform activity. Our analysis is conducted through the newly developed software PyRIS, which enables us to perform extensive multitemporal analysis of river morphodynamics from multispectral remotely sensed Landsat imagery in a fully automated fashion. We show that large rivers with low sediment supply tend to develop alternate bars that consistently migrate through long reaches, characterized at the same time by limited planform development. On the contrary, high sediment supply is associated with the development of point bars that are well-attached to the evolving meander bends and that follow temporal oscillations around the bend apexes, which in turn show rapid evlution towards complex meander shapes. Finally, rivers with intermediate rates of sediment supply develop rather steady point bars associated with slowly migrating, regular meanders. We finally discuss the results of the image analysis in the light of the properties of river planform metrics (like channel curvature and width) for the examined classes of river reaches with different sediment supply rates.

  13. Towards integrated assessment of the northern Adriatic Sea sediment budget using remote sensing

    Science.gov (United States)

    Taramelli, A.; Filipponi, F.; Valentini, E.; Zucca, F.; Gutierrez, O. Q.; Liberti, L.; Cordella, M.

    2014-12-01

    temporal pattern variability highlighted the presence of seasonal sediment dynamics linked to the seasonal cycle in river discharge and wind stress. Results suggest that sediment fluxes generate geomorphological variations in northern Adriatic Sea, which are mainly controlled by river discharge rates and modulated by the winds.

  14. Evaluation of in situ capping with clean soils to control phosphate release from sediments

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Di [State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008 (China); Ding, Shiming, E-mail: smding@niglas.ac.cn [State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008 (China); Sun, Qin [College of Environmental Science and Engineering, Hohai University, Nanjing (China); Zhong, Jicheng [State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008 (China); Wu, Wei; Jia, Fei [College of Environmental Science and Engineering, Hohai University, Nanjing (China)

    2012-11-01

    Evaluation of in situ capping with clean soils to control phosphate release from the sediments of a eutrophic bay in Lake Taihu was performed after 18 months of capping. The concentrations of dissolved reactive phosphate (DRP) in pore waters and DRP resupply from native sediments and capped sediments were determined using high-resolution dialysis (HR-Peeper) and a Zr-oxide diffusive gradients in thin films (Zr-oxide DGT) technique. The adsorption isotherm of these sediments was further investigated using a modified Langmuir model. The results showed low concentrations of DRP in pore waters with a low resupply from the sediments for sustaining pore water DRP concentration after capping. The calculated flux to the overlying water following the capping treatment was approximately half of that for the native sediments, implying that the capping reduced the release of phosphate from the sediments. The low resupply of the sediments after capping was further demonstrated by larger partitioning coefficient (K{sub p}) values and greater adsorption capacity (Q{sub max}) values, while zero equilibrium concentrations (EPC{sub 0}s) were similar to those in native sediments. The larger K{sub p} and Q{sub max} were attributed to higher active Fe and Al introduced by the capping, indicating that the binding of phosphate onto the active Fe and Al played a critical role in reducing the internal loading of phosphorous. Highlights: Black-Right-Pointing-Pointer Evaluation of capping with soils was performed through high-resolution sampling. Black-Right-Pointing-Pointer Capping decreased the concentrations of DRP in pore waters and its release to waters. Black-Right-Pointing-Pointer Capping decreased the resupply of pore water DRP from the sediments. Black-Right-Pointing-Pointer Capped sediments had stronger abilities to adsorb and retain P. Black-Right-Pointing-Pointer Active Fe and Al introduced by capping played a critical role.

  15. Human-associated fungi in deep subseafloor sediment?

    Science.gov (United States)

    Fulfer, V. M.; Kirkpatrick, J. B.; D'Hondt, S.

    2015-12-01

    Recent studies have reported fungi in marine sediment samples from depths as great as 1740 meters below seafloor (mbsf) (Rédou et al., 2014). Such studies have utilized a variety of techniques to identify fungi, including cultivation of isolates, amplicon sequencing, and metagenomics. Six recent studies of marine sediment collectively identify nearly 100 fungal taxa at the genus and species levels (Damare et al., 2006; Lai et al., 2007; Edgcomb et al., 2010; Singh et al., 2010; Orsi et al., 2013; Rédou et al., 2014). Known marine taxa are rarely identified by these studies. For individual studies with more than two taxa, between 16% and 57% of the fungal taxa are human microflora or associated with human environments (e.g., human skin or indoor air). For example, three of the six studies identified Malassezia species that are common skin inhabitants of humans and dogs. Although human-associated taxa have been identified in both shallow and deep sediment, they pose a particularly acute problem for deep subseafloor samples, where claims of a eukaryotic deep biosphere are most striking; depending on the study, 25% to 38% of species identified in sediment taken at depths greater than 40 meters are human-associated. Only one to three species have been reported from each of the four samples taken at depths greater than one km (eight species total; Rédou et al., 2014). Of these eight species, three are human-associated. This ubiquity of human-associated microflora is very problematic for interpretations of an indigenous deep subseafloor fungal community; either human-associated taxa comprise a large fraction of marine sedimentary fungi, or sample and analytical contamination is so widespread that the extent and ubiquity of a deep subseafloor fungal community remains uncertain. This highlights the need for stringent quality control measures throughout coring, sampling, and recovery of marine sediment, and when cultivating, extracting, and/or sequencing fungi from

  16. Measuring hypoxia induced metal release from highly contaminated estuarine sediments during a 40 day laboratory incubation experiment

    Energy Technology Data Exchange (ETDEWEB)

    Banks, Joanne L., E-mail: jlbanks@student.unimelb.edu.au [Department of Zoology, University of Melbourne, Victoria, 3010 Australia (Australia); Ross, D. Jeff, E-mail: Jeff.Ross@utas.edu.au [Institute of Marine and Antarctic Studies, Nubeena Crescent, Taroona, Tasmania, 7053 Australia (Australia); Keough, Michael J., E-mail: mjkeough@unimelb.edu.au [Department of Zoology, University of Melbourne, Victoria, 3010 Australia (Australia); Eyre, Bradley D., E-mail: bradley.eyre@scu.edu.au [Centre for Coastal Biogeochemistry, School of Environmental Science and Management, Southern Cross University, PO Box 157, Lismore, NSW, 2480 Australia (Australia); Macleod, Catriona K., E-mail: Catriona.Macleod@utas.edu.au [Institute of Marine and Antarctic Studies, Nubeena Crescent, Taroona, Tasmania, 7053 Australia (Australia)

    2012-03-15

    Nutrient inputs to estuarine and coastal waters worldwide are increasing and this in turn is increasing the prevalence of eutrophication and hypoxic and anoxic episodes in these systems. Many urbanised estuaries are also subject to high levels of anthropogenic metal contamination. Environmental O{sub 2} levels may influence whether sediments act as sinks or sources of metals. In this study we investigated the effect of an extended O{sub 2} depletion event (40 days) on fluxes of trace metals (and the metalloid As) across the sediment-water interface in sediments from a highly metal contaminated estuary in S.E. Tasmania, Australia. We collected sediments from three sites that spanned a range of contamination and measured total metal concentration in the overlying water using sealed core incubations. Manganese and iron, which are known to regulate the release of other divalent cations from sub-oxic sediments, were released from sediments at all sites as hypoxia developed. In contrast, the release of arsenic, cadmium, copper and zinc was comparatively low, most likely due to inherent stability of these elements within the sediments, perhaps as a result of their refractory origin, their association with fine-grained sediments or their being bound in stable sulphide complexes. Metal release was not sustained due to the powerful effect of metal-sulphide precipitation of dissolved metals back into sediments. The limited mobilisation of sediment bound metals during hypoxia is encouraging, nevertheless the results highlight particular problems for management in areas where hypoxia might occur, such as the release of metals exacerbating already high loads or resulting in localised toxicity. - Highlights: Black-Right-Pointing-Pointer Metal contaminated sediments exposed to long-term hypoxia released Mn and Fe pulses. Black-Right-Pointing-Pointer As flux increased under anoxic conditions Cd, Cu and Zn fluxes occurred only during the first week of hypoxia. Black

  17. Sediment dynamics in Alpine basins

    Science.gov (United States)

    Habersack, Helmut; Liébault, Fred; Comiti, Francesco

    2017-08-01

    In rivers and streams and of the European Alps, sediment transport processes are of great relevance due to their ecological (e.g. aquatic habitats), energy (e.g. reservoir sedimentation) and risk-related (floods and debris flows) consequences. In fact, sediment fluxes are crucial to maintain a good ecological status of watercourses (required by the EU ;Water Framework Directive;, WFD, 2000), as they provide the hydromorphological conditions supporting dynamic aquatic ecosystems (Fryirs and Brierley, 2013; Wohl et al., 2015; Gurnell et al., 2016). Indeed, the key issue to ameliorate river hydrogeomorphological - and thus ecological - status and to comply with WFD provisions lies in allowing the natural processes of sediment and wood supply and transport to take place as much as possible, given the constraints imposed by the non-eliminable uses of each river (Comiti, 2012; Liébault et al., 2013). Specifically river continuity is mentioned in the WFD not only for biota but also sediments, which is hardly discussed in river management so far and almost no concrete measures to improve sediment continuity have been implemented so far (Habersack et al., 2016).

  18. NASA Soil Moisture Active Passive Mission Status and Science Highlights

    Science.gov (United States)

    Yueh, Simon; Entekhabi, Dara; O'Neill, Peggy; Entin, Jared

    2017-01-01

    The Soil Moisture Active Passive (SMAP) observatory was launched January 31, 2015, and its L-band radiometer and radar instruments became operational during April 2015. This paper provides a summary of the quality assessment of its baseline soil moisture and freeze/thaw products as well as an overview of new products. The first new product explores the Backus Gilbert optimum interpolation based on the oversampling characteristics of the SMAP radiometer. The second one investigates the disaggregation of the SMAP radiometer data using the European Space Agency's Sentinel-1 C-band synthetic aperture radar (SAR) data to obtain soil moisture products at about 1 to 3 km resolution. In addition, SMAPs L-band data have been found useful for many scientific applications, including depictions of water cycles, vegetation opacity, ocean surface salinity and hurricane ocean surface wind mapping. Highlights of these new applications will be provided.The SMAP soil moisture, freeze/taw state and SSSprovide a synergistic view of water cycle. For example, Fig.7 illustrates the transition of freeze/thaw state, change of soilmoisture near the pole and SSS in the Arctic Ocean fromApril to October in 2015 and 2016. In April, most parts ofAlaska, Canada, and Siberia remained frozen. Melt onsetstarted in May. Alaska, Canada, and a big part of Siberia havebecome thawed at the end of May; some freshwater dischargecould be found near the mouth of Mackenzie in 2016, but notin 2015. The soil moisture appeared to be higher in the Oband Yenisei river basins in Siberia in 2015. As a result,freshwater discharge was more widespread in the Kara Seanear the mouths of both rivers in June 2015 than in 2016. TheNorth America and Siberia have become completely thawedin July. After June, the freshwater discharge from other riversinto the Arctic, indicated by blue, also became visible. Thefreeze-up started in September and the high latitude regionsin North America and Eurasia became frozen. Comparing

  19. Local controls on sediment accumulation and distribution in a fjord in the West Antarctic Peninsula: implications for palaeoenvironmental interpretations

    Directory of Open Access Journals (Sweden)

    Yuribia P. Munoz

    2016-08-01

    Full Text Available We analyse surface sediment and its distribution in Flandres Bay, West Antarctic Peninsula, in order to understand modern day sediment dispersal patterns in a fjord with retreating, tidewater glaciers. The surface sediment descriptions of 41 cores are included in this study. The sediment facies described include muddy diatomaceous ooze, diatomaceous mud, pebbly mud, sandy mud and mud, with scattered pebbles present in most samples. In contrast to a traditional conceptual model of glacial sediment distribution in fjords, grain size in Flandres Bay generally coarsens from the inner to outer bay. The smallest grain size sediments were found in the bay head and are interpreted as fine-grained deposits resulting from meltwater plumes and sediment gravity flows occurring close to the glacier front. The middle of the bay is characterized by a high silt percentage, which correlates to diatom-rich sediments. Sediments in the outer bay have a high component of coarse material, which is interpreted as being the result of winnowing from currents moving from the Bellingshausen Sea into the Gerlache Strait. Palaeoenvironmental reconstructions of glacial environments often use grain size as an indicator of proximity to the ice margin. After a detailed analysis of a large number of cores collected in the study area, our findings highlight the variability in sedimentation patterns within a fjord and provide a valuable evidence of the complexity that may occur in the sedimentary record.

  20. Polycyclic Aromatic Hydrocarbons in Urban Stream Sediments

    Directory of Open Access Journals (Sweden)

    Jejal Reddy Bathi

    2012-01-01

    Full Text Available Polycyclic aromatic hydrocarbons (PAHs are persistent organic pollutants of high environmental concern with known carcinogenic activity. Although literature documents PAH fate in urban runoff, little is known about their distribution on sediment sizes, which is essential for determining their treatability and fate in receiving waters. This paper has quantified the concentrations of selected PAHs in urban creek sediments and examined possible relationships between sediment PAH content and sediment characteristics, such as particle size, volatile organic content (VOC, and sediment chemical oxygen demand (SCOD. SCOD, VOC, and PAH concentrations of sediments showed a bimodal distribution by particle size. The large diameter sediments had the highest VOC and also had the highest PAH concentrations. The spatial variation of PAH content by sediment sizes also was statistically significant; however, the mass of the PAH material was significantly affected by the relative abundance of the different particle size classes in the sediment mixtures.

  1. Regional Sediment Analysis of Mississippi River Sediment Transport and Hydrographic Survey Data

    National Research Council Canada - National Science Library

    Thorne, Colin

    2002-01-01

    ...s. Sediments generated through channel instability are carried downstream to cause sedimentation problems in flood control channels, destroy wetlands and lakes, adversely impact fish and wildlife...

  2. The analysis of macromolecular interactions by sedimentation equilibrium.

    Science.gov (United States)

    Ghirlando, Rodolfo

    2011-05-01

    The study of macromolecular interactions by sedimentation equilibrium is a highly technical method that requires great care in both the experimental design and data analysis. The complexity of the interacting system that can be analyzed is only limited by the ability to deconvolute the exponential contributions of each of the species to the overall concentration gradient. This is achieved in part through the use of multi-signal data collection and the implementation of soft mass conservation. We illustrate the use of these constraints in SEDPHAT through the study of an A+B+B⇌AB+B⇌ABB system and highlight some of the technical challenges that arise. We show that both the multi-signal analysis and mass conservation result in a precise and robust data analysis and discuss improvements that can be obtained through the inclusion of data from other methods such as sedimentation velocity and isothermal titration calorimetry. Published by Elsevier Inc.

  3. The analysis of macromolecular interactions by sedimentation equilibrium

    Science.gov (United States)

    Ghirlando, Rodolfo

    2010-01-01

    The study of macromolecular interactions by sedimentation equilibrium is a highly technical method that requires great care in both the experimental design and data analysis. The complexity of the interacting system that can be analyzed is only limited by the ability to deconvolute the exponential contributions of each of the species to the overall concentration gradient. This is achieved in part through the use of multi-signal data collection and the implementation of soft mass conservation. We illustrate the use of these constraints in SEDPHAT through the study of an A + B + B ⇌ AB + B ⇌ ABB system and highlight some of the technical challenges that arise. We show that both the multi-signal analysis and mass conservation result in a precise and robust data analysis and discuss improvements that can be obtained through the inclusion of data from other methods such as sedimentation velocity and isothermal titration calorimetry. PMID:21167941

  4. Sediment composition influences spatial variation in the abundance of human pathogen indicator bacteria within an estuarine environment.

    Directory of Open Access Journals (Sweden)

    Tracy L Perkins

    Full Text Available Faecal contamination of estuarine and coastal waters can pose a risk to human health, particularly in areas used for shellfish production or recreation. Routine microbiological water quality testing highlights areas of faecal indicator bacteria (FIB contamination within the water column, but fails to consider the abundance of FIB in sediments, which under certain hydrodynamic conditions can become resuspended. Sediments can enhance the survival of FIB in estuarine environments, but the influence of sediment composition on the ecology and abundance of FIB is poorly understood. To determine the relationship between sediment composition (grain size and organic matter and the abundance of pathogen indicator bacteria (PIB, sediments were collected from four transverse transects of the Conwy estuary, UK. The abundance of culturable Escherichia coli, total coliforms, enterococci, Campylobacter, Salmonella and Vibrio spp. in sediments was determined in relation to sediment grain size, organic matter content, salinity, depth and temperature. Sediments that contained higher proportions of silt and/or clay and associated organic matter content showed significant positive correlations with the abundance of PIB. Furthermore, the abundance of each bacterial group was positively correlated with the presence of all other groups enumerated. Campylobacter spp. were not isolated from estuarine sediments. Comparisons of the number of culturable E. coli, total coliforms and Vibrio spp. in sediments and the water column revealed that their abundance was 281, 433 and 58-fold greater in sediments (colony forming units (CFU/100g when compared with the water column (CFU/100ml, respectively. These data provide important insights into sediment compositions that promote the abundance of PIB in estuarine environments, with important implications for the modelling and prediction of public health risk based on sediment resuspension and transport.

  5. Sediment composition influences spatial variation in the abundance of human pathogen indicator bacteria within an estuarine environment.

    Science.gov (United States)

    Perkins, Tracy L; Clements, Katie; Baas, Jaco H; Jago, Colin F; Jones, Davey L; Malham, Shelagh K; McDonald, James E

    2014-01-01

    Faecal contamination of estuarine and coastal waters can pose a risk to human health, particularly in areas used for shellfish production or recreation. Routine microbiological water quality testing highlights areas of faecal indicator bacteria (FIB) contamination within the water column, but fails to consider the abundance of FIB in sediments, which under certain hydrodynamic conditions can become resuspended. Sediments can enhance the survival of FIB in estuarine environments, but the influence of sediment composition on the ecology and abundance of FIB is poorly understood. To determine the relationship between sediment composition (grain size and organic matter) and the abundance of pathogen indicator bacteria (PIB), sediments were collected from four transverse transects of the Conwy estuary, UK. The abundance of culturable Escherichia coli, total coliforms, enterococci, Campylobacter, Salmonella and Vibrio spp. in sediments was determined in relation to sediment grain size, organic matter content, salinity, depth and temperature. Sediments that contained higher proportions of silt and/or clay and associated organic matter content showed significant positive correlations with the abundance of PIB. Furthermore, the abundance of each bacterial group was positively correlated with the presence of all other groups enumerated. Campylobacter spp. were not isolated from estuarine sediments. Comparisons of the number of culturable E. coli, total coliforms and Vibrio spp. in sediments and the water column revealed that their abundance was 281, 433 and 58-fold greater in sediments (colony forming units (CFU)/100g) when compared with the water column (CFU/100ml), respectively. These data provide important insights into sediment compositions that promote the abundance of PIB in estuarine environments, with important implications for the modelling and prediction of public health risk based on sediment resuspension and transport.

  6. Spatial and temporal patterns of turbidity, sediment concentration and load across nested scales in an urban watershed

    Science.gov (United States)

    Kemper, J. T.; Welty, C.; Miller, A. J.

    2016-12-01

    In a highly regulated area such as the Chesapeake Bay watershed, suspended sediment is a matter of primary concern. However, there are few continuous sediment-concentration records available to quantify urban sediment loads. Near real-time turbidity and discharge data have been collected continuously for more than three years at six stream gages representing three nested watershed scales (1-2 sq km, 5-6 sq km, 14 sq km) in the highly impervious Dead Run watershed, located in Baltimore County, MD. Suspended sediment point samples have been collected for multiple storm events at five of the six sites, to establish provisional relationships between turbidity and suspended sediment concentrations. Using these calculated relationships and USGS discharge data, we can quantify sediment loads at each station. Turbidity-discharge relationships vary both spatially and temporally, highlighting the extreme heterogeneity of an urban watershed. Spatially, relationships change from headwaters to mouth, potentially suggesting a variation in sediment sources. Temporally, relationships change both seasonally and annually. The lowest turbidity values are consistently seen in the fall, while values in winter, spring, and summer display a high inter-annual variability. Sediment loads and yields calculated for four representative storms are compared across nested watershed scales to assess evidence for sources or sinks at different locations within the drainage network. Yields at the mouth of the watershed (DRKR) for large storms were higher than an area-weighted average of the two contributing sites (DR3, DR4), potentially suggesting additional source areas of sediment within the watershed. This highlights the ability of near real-time data to assist in developing more effective approaches in mitigating sediment transport by helping to identifying consistent trends, locations of hot spots, and patterns of sediment arrival.

  7. The impact of feeding Cyprinids on river bed sediment structures and grain entrainment

    Science.gov (United States)

    Pledger, A.; Rice, S. P.; Millett, J.

    2012-04-01

    In gravel-bed rivers, between bed-mobilising flood events, surface sediment particles are rearranged by moderate flows, generally into more stable "water-worked" positions characterised by structures of various types, including imbrication and pebble clusters. This surface layer of structured, relatively coarse particles moderates the availability of finer sub-surface sediment and the transfer of mobile material from upstream. The work reported here is focused on understanding how benthic feeding fish (Cyprinids and Salmonids) dismantle surface structures, making particles less stable and potentially rendering vulnerable sub-surface material more mobile. An increase in available, transportable sediment has implications for sediment transport fluxes, reach-scale sediment loads, channel morphology and aquatic habitat. However, almost nothing is known about the impacts of feeding fish on bed sediment structures, entrainment and sediment fluxes. A series of flume experiments will quantify the effects of six different species of fish on sediment structure and grain entrainment. The experiments will consider 1) topographic variations between pre- and post-feeding substrates using DEMs interpolated from laser scans and 2) differences in sediment entrainment from water-worked substrates exposed to feeding fish and control substrates, without fish. Using interpolated DEMs, a variety of structural parameters will be extracted (e.g. imbrication indices) to quantify the impact of each species whilst feeding. Underwater videography techniques will be used to establish entrainment thresholds and transport rates under low critical shear stresses. A second set of flume experiments are planned using a large outdoor flume to investigate the effects of feeding Barbel Barbus barbus on surface structure, to assess how disturbance and sediment mobility vary as a function of species size and shoal density. A final set of field experiments will consider the large-scale, geomorphological

  8. Modeling Loess Sedimentation

    Science.gov (United States)

    Mason, J. A.

    2009-12-01

    modern observations. I also considered patterns of deposition rate and grain size integrated over typical wind speed distributions. The results are dependent on the assumed relationship between wind conditions and dust production at the source. Assuming that dust production rate is proportional to the horizontal saltating particle flux and increases with friction velocity cubed, then the pattern of downwind dispersion is largely controlled by the high-velocity tail of the wind speed distribution, mainly associated with strong cyclones and especially cold fronts in the midlatitude settings of most major loess deposits. Ongoing work is directed toward effects of varying wind direction and irregular or shifting sink-source boundaries. Beyond the inherent limitations of a steady-state modeling approach, one major difficulty is that the dust grain size distribution at the source is unknown, although large changes in that distribution result in relatively modest change in downwind sedimentation patterns. Other important sources of uncertainty include the use of typical fully dispersed particle size analyses, despite evidence that some loess was transported as aggregates, and the effects of spatially variable post-depositional erosion and compaction on observed patterns of loess thickness.

  9. Reactive iron in marine sediments

    Science.gov (United States)

    Canfield, Donald E.

    1989-01-01

    The influence of reactive iron oxides on sediment pore-water chemistry is considered in detail. A carefully calibrated extraction scheme is used to determine the depth distributions of reactive iron phases at two very different localities: the relatively iron-rich Mississippi Delta and the relatively iron-poor FOAM site in Long Island Sound. Closed system incubations are used to characterize the rates of reaction between sulfide and both naturally occurring and pure iron mineral phases. Rates of iron liberation to pore solution are measured in the presence and absence of sulfate reduction, and the origin of dissolved iron in organic-rich sediments is speculated upon.

  10. Installing Piezometers in Deepwater Sediments

    Science.gov (United States)

    Lee, David R.; Harvey, F. Edwin

    1996-04-01

    A new method has been developed for installing piezometers in the sediments of deep harbors and lakes, where it has been difficult to measure hydrogeological parameters and collect pore waters for geochemical analyses. Using an underwater hammer operated from the surface, piezometers have been installed as much as 12 m below the water-sediment interface. The piezometer screen is held in place by barbs on the drive head and is connected to the water surface via flexible tubing. These piezometers have been installed from boats and from ice cover in water up to 30 m deep. However, installation in water more than 100 m deep should be possible.

  11. Dredged sediments as a resource for brick production: Possibilities and barriers from a consumers’ perspective

    Energy Technology Data Exchange (ETDEWEB)

    Cappuyns, Valérie, E-mail: valerie.cappuyns@kuleuven.be; Deweirt, Valentine; Rousseau, Sandra

    2015-04-15

    Highlights: • Consumers are suspicious towards bricks produced from dredged sediments. • Technical quality, safety and environmental impacts are considered key characteristics. • Public has insufficient knowledge on bricks produced from dredged sediments. • Sensitization and provision of information to customers are of primary importance. - Abstract: A possible solution for the oversupply of dredged sediments is their use as a raw material in brick production. Despite the fact that several examples (e.g., Agostini et al., 2007; Hamer and Karius, 2002; Xu et al., 2014) show that this application is feasible, some economic, technical and social limitations interfere with the development of a market of dredged materials in brick production in Flanders. While we describe the main characteristics of the supply side, we focus on the limitations and barriers from the demand side in the present study. Based on a consumers survey we analyze consumers’ risk perceptions and attitudes towards bricks produced from dredged sediments. Consumers in Flanders are rather suspicious with respect to bricks produced from dredged sediments and their risk perception is mainly determined by the possibility of a bad bargain (brick of inferior quality) and the connotation with chemical contamination. The willingness to pay for bricks made from dredged sediments is mainly influenced by the age of the respondents, as well environmental awareness, and the respondents’ belief in their ability to influence environmental problems. Sensitization and information of customers seems to be of primary importance to make dredged-sediment-derived bricks a successful product.

  12. Does bioleaching represent a biotechnological strategy for remediation of contaminated sediments?

    Energy Technology Data Exchange (ETDEWEB)

    Fonti, Viviana, E-mail: v.fonti@univpm.it; Dell' Anno, Antonio; Beolchini, Francesca

    2016-09-01

    Bioleaching is a consolidated biotechnology in the mining industry and in bio-hydrometallurgy, where microorganisms mediate the solubilisation of metals and semi-metals from mineral ores and concentrates. Bioleaching also has the potential for ex-situ/on-site remediation of aquatic sediments that are contaminated with metals, which represent a key environmental issue of global concern. By eliminating or reducing (semi-)metal contamination of aquatic sediments, bioleaching may represent an environmentally friendly and low-cost strategy for management of contaminated dredged sediments. Nevertheless, the efficiency of bioleaching in this context is greatly influenced by several abiotic and biotic factors. These factors need to be carefully taken into account before selecting bioleaching as a suitable remediation strategy. Here we review the application of bioleaching for sediment bioremediation, and provide a critical view of the main factors that affect its performance. We also discuss future research needs to improve bioleaching strategies for contaminated aquatic sediments, in view of large-scale applications. - Highlights: • Bioleaching may represent a sustainable strategy for contaminated dredged sediments • The performance is greatly influenced by several abiotic and biotic factors • Geochemical characteristics and metal partitioning have a key role • Sulphide minerals in the sediment are a favorable element • Microorganisms other than Fe/S oxidisers may open new perspectives.

  13. The microbial nitrogen cycling potential is impacted by polyaromatic hydrocarbon pollution of marine sediments

    Energy Technology Data Exchange (ETDEWEB)

    Scott, Nicole M.; Hess, Matthias; Bouskill, Nick J.; Mason, Olivia U.; Jansson, Janet K.; Gilbert, Jack A.

    2014-03-25

    During hydrocarbon exposure, the composition and functional dynamics of marine microbial communities are altered, favoring bacteria that can utilize this rich carbon source. Initial exposure of high levels of hydrocarbons in aerobic surface sediments can enrich growth of heterotrophic microorganisms having hydrocarbon degradation capacity. As a result, there can be a localized reduction in oxygen potential within the surface layer of marine sediments causing anaerobic zones. We hypothesized that increasing exposure to elevated hydrocarbon concentrations would positively correlate with an increase in denitrification processes and the net accumulation of dinitrogen. This hypothesis was tested by comparing the relative abundance of genes associated with nitrogen metabolism and nitrogen cycling identified in 6 metagenomes from sediments contaminated by polyaromatic hydrocarbons from the Deepwater Horizon (DWH) oil spill in the Gulf of Mexico, and 3 metagenomes from sediments associated with natural oil seeps in the Santa Barbara Channel. An additional 8 metagenomes from uncontaminated sediments from the Gulf of Mexico were analyzed for comparison. We predicted relative changes in metabolite turnover as a function of the differential microbial gene abundances, which showed predicted accumulation of metabolites associated with denitrification processes, including anammox, in the contaminated samples compared to uncontaminated sediments, with the magnitude of this change being positively correlated to the hydrocarbon concentration and exposure duration. These data highlight the potential impact of hydrocarbon inputs on N cycling processes in marine sediments and provide information relevant for system scale models of nitrogen metabolism in affected ecosystems

  14. Abundant Atribacteria in deep marine sediment from the Adélie Basin, Antarctica

    Directory of Open Access Journals (Sweden)

    Stephanie Ann Carr

    2015-08-01

    Full Text Available Bacteria belonging to the newly classified candidate phylum Atribacteria (formerly referred to as OP9 and JS1 are common in anoxic methane-rich sediments. However, the metabolic functions and biogeochemical role of these microorganisms in the subsurface remains unrealized due to the lack of pure culture representatives. In this study of deep sediment from Antarctica's Adélie Basin, collected during Expedition 318 of the Integrated Ocean Drilling Program (IODP, Atribacteria-related sequences of the 16S rRNA gene were abundant (up to 51% of the sequences and steadily increased in relative abundance with depth throughout the methane-rich zones. To better understand the metabolic potential of Atribacteria within this environment, and to compare with phylogenetically distinct Atribacteria from non-deep-sea environments, individual cells were sorted for single cell genomics from sediment collected from 97.41 meters below the seafloor from IODP Hole U1357C. As observed for non-marine Atribacteria, a partial single cell genome suggests a heterotrophic metabolism, with Atribacteria potentially producing fermentation products such as acetate, ethanol and CO2. These products may in turn support methanogens within the sediment microbial community and explain the frequent occurrence of Atribacteria in anoxic methane-rich sediments. This first report of a single cell genome from deep sediment broadens the known diversity within the Atribacteria phylum and highlights the potential role of Atribacteria in carbon cycling in deep sediment.

  15. Ancient DNA from lake sediments: Bridging the gap between paleoecology and genetics

    Directory of Open Access Journals (Sweden)

    Lumibao Candice Y

    2011-01-01

    Full Text Available Abstract Background Quaternary plant ecology in much of the world has historically relied on morphological identification of macro- and microfossils from sediments of small freshwater lakes. Here, we report new protocols that reliably yield DNA sequence data from Holocene plant macrofossils and bulk lake sediment used to infer ecological change. This will allow changes in census populations, estimated from fossils and associated sediment, to be directly associated with population genetic changes. Results We successfully sequenced DNA from 64 samples (out of 126 comprised of bulk sediment and seeds, leaf fragments, budscales, and samaras extracted from Holocene lake sediments in the western Great Lakes region of North America. Overall, DNA yields were low. However, we were able to reliably amplify samples with as few as 10 copies of a short cpDNA fragment with little detectable PCR inhibition. Our success rate was highest for sediments Conclusions An ability to extract ancient DNA from Holocene sediments potentially allows exciting new insights into the genetic consequences of long-term environmental change. The low DNA copy numbers we found in fossil material and the discovery of multiple sequence variants from single macrofossil extractions highlight the need for careful experimental and laboratory protocols. Further application of these protocols should lead to better understanding of the ecological and evolutionary consequences of environmental change.

  16. Prediction of sediment load by sediment rating curve and neural ...

    Indian Academy of Sciences (India)

    well planning studies on soil and water resources development (Yenigun et al. 2008). The estimation of this sediment load ... quickly change the rate of flow of a river. If the sampling is too infrequent, these events may be .... used a single ANN approach to establish sediment– discharge relationship and found that the ANN.

  17. Sea-level responses to sediment transport over the last ice age cycle

    Science.gov (United States)

    Ferrier, K.; Mitrovica, J. X.

    2013-12-01

    most of the Indus sediment may have been deposited during the glacial period preceding the Holocene. These simulations highlight the role that massive continent-to-ocean sediment fluxes can play in driving sea-level patterns over thousands of years. References: Dalca A.V., Ferrier K.L., Mitrovica J.X., Perron J.T., Milne G.A., Creveling J.R., 2013. On postglacial sea level - III: Incorporating sediment redistribution. Geophys. J. Int., doi: 10.1093/gji/ggt089.

  18. Environmental impact of ongoing sources of metal contamination on remediated sediments

    Energy Technology Data Exchange (ETDEWEB)

    Knox, Anna Sophia, E-mail: anna.knox@srn.doe.gov [Savannah River National Laboratory, Aiken, SC 29808 (United States); Paller, Michael H., E-mail: michael.paller@srnl.doe.gov [Savannah River National Laboratory, Aiken, SC 29808 (United States); Milliken, Charles E., E-mail: charles.milliken@srnl.doe.gov [Savannah River National Laboratory, Aiken, SC 29808 (United States); Redder, Todd M., E-mail: tredder@limno.com [LimnoTech, Ann Arbor, Minnesota 48108 (United States); Wolfe, John R., E-mail: jwolfe@limno.com [LimnoTech, Ann Arbor, Minnesota 48108 (United States); Seaman, John, E-mail: seaman@srel.uga.edu [Savannah River Ecology Laboratory, University of Georgia, Aiken, SC 29802 (United States)

    2016-09-01

    aquatic organisms, and enhance remedial effectiveness. - Highlights: • Ongoing sources of contamination are a challenge to sediment remedial methods • Active caps removed metals from ongoing sources and reduced their bioavailability • Metals from ongoing sources contaminated uncapped sediment and passive caps • Whole-body metal concentrations were lower in Lumbriculus from active caps • Active caps can protect remediated sediments from continuing contaminant influxes.

  19. Biomarker responsiveness in different tissues of caged Ruditapes philippinarum and its use within an integrated sediment quality assessment

    Energy Technology Data Exchange (ETDEWEB)

    Ramos-Gomez, Julia, E-mail: julia.ramosgomez@uca.es [UNITWIN/UNESCO/WiCoP, Departamento de Quimica Fisica, Universidad de Cadiz, Facultad de Ciencias del Mar y Ambientales, Campus Universitario de Puerto Real, 11510 Puerto Real, Cadiz (Spain); Coz, Alberto; Viguri, Javier R. [Dpto. Ingenieria Quimica y Quimica Inorganica, ETSIIT, Universidad de Cantabria, Avda. los Castros, s/n 39005 Santander (Spain); Luque, Angel [Departamento de Biologia, Universidad de Las Palmas de Gran Canaria, 35017 Las Palmas de Gran Canaria, Gran Canaria, The Canary Islands (Spain); Martin-Diaz, M. Laura [UNITWIN/UNESCO/WiCoP, Departamento de Quimica Fisica, Universidad de Cadiz, Facultad de Ciencias del Mar y Ambientales, Campus Universitario de Puerto Real, 11510 Puerto Real, Cadiz (Spain); Centro Andaluz de Ciencia y Tecnologia Marinas (CACYTMAR), Universidad de Cadiz, Campus Universitario de Puerto Real, 11510 Puerto Real, Cadiz (Spain); DelValls, T. Angel [UNITWIN/UNESCO/WiCoP, Departamento de Quimica Fisica, Universidad de Cadiz, Facultad de Ciencias del Mar y Ambientales, Campus Universitario de Puerto Real, 11510 Puerto Real, Cadiz (Spain)

    2011-07-15

    Biomarkers comprising activities of biotransformation enzymes (ethoxyresorufin-O-deethylase -EROD-, dibenzylfluorescein dealkylase -DBF-, glutathione S-transferase -GST), antioxidant enzymes (glutathione reductase -GR- and glutathione peroxidase -GPX), lipid peroxidation -LPO- and DNA strand breaks were analyzed in the clam Ruditapes philippinarum caged at Cadiz Bay, Santander Bay and Las Palmas de Gran Canaria (LPGC) Port (Spain). Sediments were characterized. Digestive gland was the most sensitive tissue to sediment contamination. In Cadiz Bay, changes in LPO regarding day 0 were related with metals. In LPGC Port, DBF, EROD, and GST activity responses suggested the presence of undetermined contaminants which might have led to DNA damage. In Santander Bay, PAHs were related with EROD activity, organic and metal contamination was found to be associated with GR and GST activities and DNA damage presented significant (p < 0.05) induction. R. philippinarum was sensitive to sediment contamination at biochemical level. Biomarkers allowed chemical exposure and sediment quality assessment. - Highlights: > Ruditapes philippinarum is sensitive to sediment contamination at biochemical level. > Digestive gland biomarkers showed the best correlations with sediment contaminants. > Presence of potentially toxic chemicals not analyzed in this research was unmasked. > Multivariate analysis allowed the identification of toxic xenobiotic and possible sources. > Inner area of Santander Bay presented the highest sediment toxicity. - Integration of Ruditapes philippinarum biomarker results and sediment chemistry distinguished xenobiotic exposure and sediment toxicity in coastal areas of Spain.

  20. Current Methods in Sedimentation Velocity and Sedimentation Equilibrium Analytical Ultracentrifugation

    Science.gov (United States)

    Zhao, Huaying; Brautigam, Chad A.; Ghirlando, Rodolfo; Schuck, Peter

    2013-01-01

    Significant progress in the interpretation of analytical ultracentrifugation (AUC) data in the last decade has led to profound changes in the practice of AUC, both for sedimentation velocity (SV) and sedimentation equilibrium (SE). Modern computational strategies have allowed for the direct modeling of the sedimentation process of heterogeneous mixtures, resulting in SV size-distribution analyses with significantly improved detection limits and strongly enhanced resolution. These advances have transformed the practice of SV, rendering it the primary method of choice for most existing applications of AUC, such as the study of protein self- and hetero-association, the study of membrane proteins, and applications in biotechnology. New global multi-signal modeling and mass conservation approaches in SV and SE, in conjunction with the effective-particle framework for interpreting the sedimentation boundary structure of interacting systems, as well as tools for explicit modeling of the reaction/diffusion/sedimentation equations to experimental data, have led to more robust and more powerful strategies for the study of reversible protein interactions and multi-protein complexes. Furthermore, modern mathematical modeling capabilities have allowed for a detailed description of many experimental aspects of the acquired data, thus enabling novel experimental opportunities, with important implications for both sample preparation and data acquisition. The goal of the current commentary is to supplement previous AUC protocols, Current Protocols in Protein Science 20.3 (1999) and 20.7 (2003), and 7.12 (2008), and provide an update describing the current tools for the study of soluble proteins, detergent-solubilized membrane proteins and their interactions by SV and SE. PMID:23377850

  1. Dynamics of suspended sediment concentration, flow discharge and sediment particle size interdependency to identify sediment source

    Science.gov (United States)

    Sadeghi, Seyed Hamidreza; Singh, Vijay P.

    2017-11-01

    Spatiotemporal behavior of sediment yield is a key for proper watershed management. This study analyzed statistical characteristics and trends of suspended sediment concentration (SCS), flow discharge (FD) and sediment particle sizes using data from 24 gage stations scattered throughout the United States. Analysis showed significant time- and location-specific differences of these variables. The median values of SSC, FD and percentage of particle sizes smaller than 63 μm (P63) for all 24 gage stations were found to be 510.236 mg l-1 (right skewed), 45.406 m3 s-1 (left skewed) and 78.648% (right skewed), respectively. Most of the stations exhibited significant trends (P management practices which may call for local or regional planning based on natural (i.e., precipitation amount, type and erosivity, watershed area, and soil erodibility) and human-affected (i.e., land use and hydraulic structures and water resources management) factors governing the study variables.

  2. Sedimentation in a river dominated estuary

    CSIR Research Space (South Africa)

    Cooper, JAG

    1993-10-01

    Full Text Available is restricted to a small flood tidal delta. Sequential aerial photography, sediment sampling and topographical surveys reveal a cyclial pattern of sedimentation that is mediated by severe fluvial floods which exceed normal energy thresholds. During severe floods...

  3. Longshore sediment transport along the Indian coast

    Digital Repository Service at National Institute of Oceanography (India)

    Chandramohan, P.; Nayak, B.U.

    An empirical sediment transport model has been developed based on longshore energy flux equation. Ship reported waves, published in Indian Daily Weather Reports, are compiled for 19 y and used for estimation of sediment transport. Annual gross...

  4. Thermodynamics of sedimentation in paucidisperse systems

    NARCIS (Netherlands)

    Hooyman, G.J.

    1956-01-01

    The previously given treatment of sedimentation phenomena in monodisperse uncharged systems with the help of thermodynamics of irreversible processes is extended to paucidisperse systems. The sedimentation rates of the components are derived by neglecting transverse effects and by introducing the

  5. Biota-Sediment Accumulation Factor Data

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Biota-Sediment Accumulation Factor contains approximately 20,000 biota-sediment accumulation factors (BSAFs) from 20 locations (mostly Superfund sites) for...

  6. Green PCB Remediation from Sediment Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The GPRSS technology is an in situ remediation technique for PCB-contaminated sediments. The technique provides an effective and safe method for sediment cleanup...

  7. Luminescence dating of delta sediments

    NARCIS (Netherlands)

    Chamberlain, Elizabeth L.; Wallinga, Jakob; Reimann, Tony; Goodbred, Steven L.; Steckler, Michael S.; Shen, Zhixiong; Sincavage, Ryan

    2017-01-01

    Deltas where luminescence dating is most essential due to organic-poor geologic records are also those where it is often most challenging due to unsuitable luminescence properties of quartz grains, associated with rapid production of young clastic sediment. One example is the

  8. Identification of carotenals in sediments

    NARCIS (Netherlands)

    Hopmans, E.C.; Schouten, S.; Rijpstra, W.I.C.; Sinninghe Damsté, J.S.

    2005-01-01

    High performance liquid chromatography with photodiode array UV–Vis detection and atmospheric pressure chemical ionization mass spectrometry was used to analyze sediment samples from the meromictic Ace Lake (Antarctica), as well as a Pliocene sapropel from the Mediterranean Sea and a Miocene marl

  9. Sediment reduction through watershed rehabilitation

    Science.gov (United States)

    Edward L. Noble

    1963-01-01

    History is replete with stories recounting the failures of man to recognize, control, and conquer the devastating effects of sediments from steep mountainous lands. Learned men have documented the reasons for the tragic downfall of highly developed civilizations in Mesopotamia, Israel, Egypt, and elsewhere. Most agree that it was not conquest of the land by an invader...

  10. Black carbon in marine sediments

    NARCIS (Netherlands)

    Middelburg, J.J.; Nieuwenhuize, J.; Van Breugel, P.

    1999-01-01

    Concentrations of black carbon were determined for a number of marine sediments. A comparison of black carbon based on thermal oxidation and hot concentrated nitric acid pretreatments revealed that the latter significantly overestimates combustion derived carbon phases. Black carbon accounts for

  11. Sediment transport under breaking waves

    DEFF Research Database (Denmark)

    Christensen, Erik Damgaard; Hjelmager Jensen, Jacob; Mayer, Stefan

    2000-01-01

    generated at the surface where the wave breaks as well as the turbulence generated near the bed due to the wave-motion and the undertow. In general, the levels of turbulent kinetic energy are found to be higher than experiments show. This results in an over prediction of the sediment transport. Nevertheless...

  12. Flocculation Dynamics of cohesive sediment

    NARCIS (Netherlands)

    Maggi, F.

    2005-01-01

    Cohesive sediment suspended in natural waters is subject not only to transport and deposition processes but also to reactions of flocculation, \\textit{i.e.} aggregation of fine particles, and breakup of aggregates. Although aggregation and breakup occur at small and very small length scales compared

  13. CHWAKA BAY MANGROVE SEDIMENTS, ZANZIBAR

    African Journals Online (AJOL)

    there was little spatial and seasonal variation in DW rates in the creek. Coupled nitrification-denitrfieation (Dn) was found to be low, but within the range measured in other mangrove sediments. Average values ranged from 0.01 to 0.45 uM Nm'Zh'I and showed strong spatial variations. The low denitrification rates observed ...

  14. Surface sedimentation at permeable pavement systems

    DEFF Research Database (Denmark)

    Støvring, Jan; Dam, Torben; Jensen, Marina Bergen

    2018-01-01

    Newly installed permeable pavement (PP) systems provide high surface infiltration capacity, but the accumulation of sediments causes a decrease in capacity over time, eventually leading to surface clogging. With the aim of investigating local sedimentation processes and the importance of restorat......Newly installed permeable pavement (PP) systems provide high surface infiltration capacity, but the accumulation of sediments causes a decrease in capacity over time, eventually leading to surface clogging. With the aim of investigating local sedimentation processes and the importance...

  15. Reservoir Sedimentation Based on Uncertainty Analysis

    OpenAIRE

    Farhad Imanshoar; Afshin Jahangirzadeh; Hossein Basser; Shatirah Akib; Babak Kamali; Tabatabaei, Mohammad Reza M.; Masoud Kakouei

    2013-01-01

    Reservoir sedimentation can result in loss of much needed reservoir storage capacity, reducing the useful life of dams. Thus, sufficient sediment storage capacity should be provided for the reservoir design stage to ensure that sediment accumulation will not impair the functioning of the reservoir during the useful operational-economic life of the project. However, an important issue to consider when estimating reservoir sedimentation and accumulation is the uncertainty involved in reservoir ...

  16. Regional Models for Sediment Toxicity Assessment

    Science.gov (United States)

    This paper investigates the use of empirical models to predict the toxicity of sediment samples within a region to laboratory test organisms based on sediment chemistry. In earlier work, we used a large nationwide database of matching sediment chemistry and marine amphipod sedim...

  17. SEDIMENT MANAGEMENT IN FLOOD CONTROL DAMS

    OpenAIRE

    Pattanapanchai, Maneechit; Shah, Farhed A.; Annandale, George

    2002-01-01

    Reservoir sedimentation reduces economic value and longevity of flood control dams. Periodic sediment removal allows extension of reservoir life. An optimal control model is developed to evaluate alternative sediment management strategies for flood control dams. An illustrative empirical analysis shows that sustainable management is economically desirable for a wide range of parameter values.

  18. South African Climates: Highlights From International Ocean Discovery Program Expedition 361

    Science.gov (United States)

    Hemming, S. R.; Hall, I. R.; LeVay, L.

    2016-12-01

    International Ocean Discovery Program Expedition 361 drilled six sites on the southeast African margin and in the Indian-Atlantic ocean gateway, southwest Indian Ocean, from 30 January to 31 March 2016. In total, 5175 m of core was recovered, with an average recovery of 102%, during 29.7 days of on-site operations. The sites, situated in the Mozambique Channel, at locations directly influenced by discharge from the Zambezi and Limpopo River catchments, the Natal Valley, the Agulhas Plateau, and the Cape Basin were targeted to reconstruct the history of the Greater Agulhas Current System over the past 5 Ma. The Agulhas Current transports 70 Sv of warm and saline surface waters from the tropical Indian Ocean along the East African margin to the tip of Africa. Exchanges of heat and moisture with the atmosphere influence southern African rainfall patterns. Recent ocean model and paleoceanographic data further point at a potential role of the Agulhas Current in controlling the strength and mode of the Atlantic Meridional Overturning Circulation (AMOC) during the Late Pleistocene. The main objectives of the expedition were to document the oceanographic properties of the Agulhas Current through tectonic and climatic changes during the Plio-Pleistocene, to determine the dynamics of the Indian-Atlantic gateway circulation during this time, to examine the connection of the Agulhas leakage and AMOC, to address the influence of the Agulhas Current on African terrestrial climates and potential links to Human evolution. Additionally, the Expedition set out to fulfill the needs of the Ancillary Project Letter, consisting of high-resolution interstitial water samples that will, and to constrain the temperature and salinity profiles of the ocean during the Last Glacial Maximum. Here we highlight some of the expedition successes and show how it has made major strides toward fulfilling each of these objectives. The recovered sequences allowed complete spliced stratigraphic sections

  19. Highlights 1993

    Energy Technology Data Exchange (ETDEWEB)

    1993-11-01

    Current research programs at Lawrence Berkeley Laboratory are presented. The topics include: the genetic basis for breast cancer, the Advanced Light Source, selenium characterization in soils via x-ray absorption spectroscopy, automated colony sorting in efforts of map the human genome, cancer drugs, the Sudbury Neutrino Observatory (SNO), atomic force microscopes (AFM), mapping the radon risk in homes, ketene research, tracking B mesons and the search for the top quark, computerized scientific visualization, technology transfer efforts, and astronomy in the classroom.

  20. HAWC highlights

    Energy Technology Data Exchange (ETDEWEB)

    Jardin-Blicq, Armelle [Max Planck Institut fuer Kernphysik (Germany); Collaboration: HAWC-Collaboration

    2016-07-01

    The High-Altitude Water Cherenkov (HAWC) Observatory was completed and began full operation on March 20, 2015. The detector consists of an array of 300 water tanks, each containing 200 tons of purified water and instrumented with 4 PMTs. Located at an elevation of 4100m a.s.l. near the Sierra Negra volcano in central Mexico, HAWC observes gamma rays in the 0.1-100 TeV range and has a sensitivity to TeV-scale gamma-ray sources an order of magnitude better than previous air-shower arrays. It has 2 sr field-of-view and >90% duty cycle make HAWC an ideal instrument for surveying the high-energy sky. We describe the HAWC detector and its performance characteristics and report initial results from the first months of operation.

  1. AGARD Highlights.

    Science.gov (United States)

    1980-09-01

    m) IT ala (1) a freccia ES sensacion (r) artificial ES indicador (m) tipo A NE pillvleugel FR I sensation MI artificielle FR indicateur (m) type A...visualizzatore (m) tipo A TU W tipi kanat fT sensirie Nf errificiale NE A-scharmt iro) NE kunstmastig I stuurkracht) gevroel In) PO dcran Wm tipo A 10596...tique - Multivariable Analysis and Design Techniques - Techniques de Conception et d’Analyse i Variables Multiples - Fatigue Testing Methodology

  2. AGARD Highlights.

    Science.gov (United States)

    1979-03-01

    mu s ’ uu d uuug h !ru ’ .t ’I I t ul ’ is ’ us i is - Jack Bi iuii l i _ iri: graslua tesi lu t t~ ~—l . t s ’s’c’i ’ iuuug .1I).it lis’i~u m it t...u wIt , I )r K ,hta niermt f ’ cmmi e l am uc h de’h erie uraf io’m atid u mm u it ceum itb at reac h imt e ’ss - l ime’ uuuupi us’ , c’ I )u 1) 1

  3. Brookhaven highlights

    Energy Technology Data Exchange (ETDEWEB)

    Rowe, M.S.; Cohen, A.; Greenberg, D.; Seubert, L. (eds.)

    1992-01-01

    This publication provides a broad overview of the research programs and efforts being conducted, built, designed, and planned at Brookhaven National Laboratory. This work covers a broad range of scientific disciplines. Major facilities include the Alternating Gradient Synchrotron (AGS), with its newly completed booster, the National Synchrotron Light Source (NSLS), the High Flux Beam Reactor (HFBR), and the RHIC, which is under construction. Departments within the laboratory include the AGS department, accelerator development, physics, chemistry, biology, NSLS, medical, nuclear energy, and interdepartmental research efforts. Research ranges from the pure sciences, in nuclear physics and high energy physics as one example, to environmental work in applied science to study climatic effects, from efforts in biology which are a component of the human genome project to the study, production, and characterization of new materials. The paper provides an overview of the laboratory operations during 1992, including staffing, research, honors, funding, and general laboratory plans for the future.

  4. Highlights 2005

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-02-15

    This document summarizes a year of activities for the ESRF (European synchrotron radiation facilities), this facility serves 31 beamlines that represent 34 end stations that can be run independently. This document is organized into 9 parts. Part 1: 'high resolution and resonance scattering' deals with surface science and magnetism at high pressure, in particular results are presented for samarium and europium chalcogenides. A cross-section of a variety of applications are presented, they range from glass physics to the understanding of thermoelectric materials. Part 2: 'materials sciences' deals with material behaviour under extreme conditions (metallic sulfur above 100 GPa,...) general applications of X-ray diffraction : stress and strain studies, assessment of excess free volume in metallic glasses, or grain nucleation and growth kinetics during solidification. Part 3: 'soft condensed matter'. Part 4: 'structural biology'. Part 5: 'surface and interface science' (at ESRF surfaces and interfaces are studied at about 50% of all beamlines). A study shows the existence of ordered SiGe domains in the interior of the small Ge islands in Si, whereas bulk SiGe alloy is disordered. Other studies shed light on the surprisingly different magnetic behaviour of ultra-thin cobalt and nickel films on a platinum surface. Part 6 : 'X-ray absorption and magnetic scattering'. Many of the studies push the limits of methods using high pressure, high magnetic fields, high and low temperature with absorption and scattering techniques. There are also examples of measurements on the femtosecond time scale using the core-hole clock method and on femto-meter length scale in magnetostriction measurements. Part 7: 'X-ray imaging and optics'. Part 8: 'the X-ray source'. Part 9: 'facts and figures'. (A.C.)

  5. MAGIC highlights

    Directory of Open Access Journals (Sweden)

    López-Coto Rubén

    2016-01-01

    Full Text Available The present generation of Imaging Air Cherenkov Telescopes (IACTs has greatly improved our knowledge on the Very High Energy (VHE side of our Universe. The MAGIC IACTs operate since 2004 with one telescope and since 2009 as a two telescope stereoscopic system. I will outline a few of our latest and most relevant results: the discovery of pulsed emission from the Crab pulsar at VHE, recently found to extend up to 400 GeV and along the “bridge” of the light curve, the measurement of the Crab nebula spectrum over three decades of energy, the discovery of VHE γ-ray emission from the PWN 3C 58, the very rapid emission of IC 310, in addition to dark matter studies. The results that will be described here and the planned deep observations in the next years will pave the path for the future generation of IACTs.

  6. OPERA HIGHLIGHTS

    Directory of Open Access Journals (Sweden)

    Thomas Strauss

    2013-12-01

    Full Text Available The OPERA experiment is a long baseline neutrino oscillation  experiment aimed at observing the νμ → ντ neutrino oscillation in the CERN neutrino to Gran Sasso beamline in the appearance mode by detecting the τ-decay. Here I will summarize the results from the run years 2008–10 with an update on observed rare decay topologies and the results of the neutrino velocity measurements.

  7. Influence of Sedimentation Rate on the Metal Contamination in Sediments of Bohai Bay, China.

    Science.gov (United States)

    Zhang, Yan; Lu, Xueqiang; Shao, Xiaolong; Liu, Honglei; Xing, Meinan; Zhao, Feng; Li, Xiaojuan; Yuan, Min

    2015-10-01

    Metal concentration in marine sediments is influenced by sedimentation rate. In this study, the metal concentration in sediments of Bohai Bay, China, was adjusted by sedimentation rate, which was derived from the radionuclide dating method. The results showed that the sedimentation rate of Bohai Bay sediments increased from 0.3 to 0.55 g/a over time, especially in the last 30 years since the economic reform in China. The sequence of metal concentrations (mg/kg) is: Cr(97.41) > Zn(73.14) > Cu(20.59) > Pb(16.42) > Cd(0.49). Through the adjustment, the change of metal concentration in sediment cores increased obviously from bottom to surface sediments. It indicated that the increasing sedimentation rate of Bohai Bay in recent years diluted the metal concentration in the sediment.

  8. Influence of Chironomus riparius (Diptera, Chironomidae) and Tubifex tubifex (Annelida, Oligochaeta) on oxygen uptake by sediments. Consequences of uranium contamination

    Energy Technology Data Exchange (ETDEWEB)

    Lagauzere, S. [Laboratoire de Radioecologie et d' Ecotoxicologie, Institut de Radioprotection et de Surete Nucleaire (IRSN), DEI/SECRE/LRE, Cadarache 186, BP 3, F-13115 Cedex, Saint Paul Lez Durance (France)], E-mail: lagauzere@gmail.com; Pischedda, L.; Cuny, P. [Laboratoire de Microbiologie, Geochimie et Ecologie Marines, UMR 6117 CNRS/COM/Universite de la Mediterranee, Campus de Luminy, Case 901, F-13288 Cedex 09, Marseille (France); Gilbert, F. [EcoLab, Laboratoire d' Ecologie Fonctionnelle, UMR 5245 CNRS/INP/Universite Paul Sabatier, 29 Rue Jeanne Marvig, F-31055 Cedex 4, Toulouse (France); Stora, G. [Laboratoire de Microbiologie, Geochimie et Ecologie Marines, UMR 6117 CNRS/COM/Universite de la Mediterranee, Campus de Luminy, Case 901, F-13288 Cedex 09, Marseille (France); Bonzom, J.-M. [Laboratoire de Radioecologie et d' Ecotoxicologie, Institut de Radioprotection et de Surete Nucleaire (IRSN), DEI/SECRE/LRE, Cadarache 186, BP 3, F-13115 Cedex, Saint Paul Lez Durance (France)

    2009-04-15

    The diffusive oxygen uptake (DOU) of sediments inhabited by Chironomus riparius and Tubifex tubifex was investigated using a planar oxygen optode device, and complemented by measurements of bioturbation activity. Additional experiments were performed within contaminated sediments to assess the impact of uranium on these processes. After 72 h, the two invertebrate species significantly increased the DOU of sediments (13-14%), and no temporal variation occurred afterwards. Within contaminated sediments, it was already 24% higher before the introduction of the organisms, suggesting that uranium modified the sediment biogeochemistry. Although the two species firstly reacted by avoidance of contaminated sediment, they finally colonized it. Their bioturbation activity was reduced but, for T. tubifex, it remained sufficient to induce a release of uranium to the water column and an increase of the DOU (53%). These results highlight the necessity of further investigations to take into account the interactions between bioturbation, microbial metabolism and pollutants. - This study highlights the ecological importance of bioturbation in metal-contaminated sediments.

  9. Effects of cadmium accumulation from suspended sediments and phytoplankton on the Oyster Saccostrea glomerata

    Energy Technology Data Exchange (ETDEWEB)

    Schmitz, Helena A.; Maher, William A., E-mail: bill.maher@canberra.edu.au; Taylor, Anne M.; Krikowa, Frank

    2015-03-15

    Highlights: • Saccostrea glomerata accumulated cadmium from sediments and phytoplankton. • Effects were similar for both pathways. • Antioxidant capacity, lipid peroxidation and lysosomal destabilisation were affected. • Clear exposure–dose–response relationships were demonstrated. - Abstract: Metals are accumulated by filter feeding organisms via water, ingestion of suspended sediments or food. The uptake pathway can affect metal toxicity. Saccostrea glomerata were exposed to cadmium through cadmium-spiked suspended sediments (19 and 93 μg/g dry mass) and cadmium-enriched phytoplankton (1.6–3 μg/g dry mass) and cadmium uptake and effects measured. Oysters accumulated appreciable amounts of cadmium from both low and high cadmium spiked suspended sediment treatments (5.9 ± 0.4 μg/g and 23 ± 2 μg/g respectively compared to controls 0.97 ± 0.05 μg/g dry mass). Only a small amount of cadmium was accumulated by ingestion of cadmium-enriched phytoplankton (1.9 ± 0.1 μg/g compared to controls 1.2 ± 0.1 μg/g). In the cadmium spiked suspended sediment experiments, most cadmium was desorbed from sediments and cadmium concentrations in S. glomerata were significantly related to dissolved cadmium concentrations (4–21 μg/L) in the overlying water. In the phytoplankton feeding experiment cadmium concentrations in overlying water were <0.01 μg/L. In both exposure experiments, cadmium-exposed oysters showed a significant reduction in total antioxidant capacity and significantly increased lipid peroxidation and percentage of destabilised lysosomes. Destabilised lysosomes in the suspended sediments experiments also resulted from stress of exposure to the suspended sediments. The study demonstrated that exposure to cadmium via suspended sediments and to low concentrations of cadmium through the ingestion of phytoplankton, can cause sublethal stress to S. glomerata.

  10. Sources of fine sediment stored in agricultural lowland streams, Midwest, USA

    Science.gov (United States)

    Lamba, Jasmeet; Thompson, Anita M.; Karthikeyan, K.G.; Fitzpatrick, Faith A.

    2015-01-01

    Agricultural activities can accelerate the offsite transport of productive soil from fields leading to stream water quality degradation. Identification of the nature and relative contribution of different sources to fine-grained sediment (e.g., silts, clays) in streams is important to effectively focus agricultural best management practices in watersheds. Sediment fingerprinting techniques through the use of geochemical tracers are commonly used to differentiate relative contribution from various sources. Research was conducted in lowland streams in the Pleasant Valley watershed in South Central Wisconsin (USA) to identify provenance of fine-grained sediment deposits and evaluate the impact of land use on relative contributions from the following potential sources: cropland, pasture, woodland, and eroding stream banks. Results show that both agriculture (croplands and pastures) and eroding stream banks are primary sources to fine sediment deposits on the stream bed with contributions ranging from 19 to 100% and 0 to 81%, respectively. The increase in area under agricultural land use within a subwatershed results in greater contribution from agriculture (R2 = 0.846, p = 0.0034). Relative contributions from eroding stream banks increased with increasing area under grasslands and woodlands within a subwatershed (R2 = 0.814, p = 0.0055). Subwatersheds with greater mass of fine sediment deposited on the stream bed per unit area should be prioritized for best management practices. The conservation practices should be targeted to stream banks or croplands depending on the dominant source of fine sediment within a subwatershed. Site specific changes in relative contributions from different sources to fine-grained sediment in this watershed highlights the complexities involved in sediment transport dynamics. The nested sampling sites helped determine that sediment dynamics at the subwatershed scale need to be considered for application of targeted conservation

  11. Hydrocarbon biodegradation in intertidal wetland sediments.

    Science.gov (United States)

    McGenity, Terry J

    2014-06-01

    Intertidal wetlands, primarily salt marsh, mangrove and mudflats, which provide many essential ecosystem services, are under threat on numerous fronts; a situation that is made worse by crude-oil pollution. Microbes are the main vehicle for remediation of such sediments, and new discoveries, such as novel biodegradation pathways, means of accessing oil, multi-species interactions, and community-level responses to oil addition, are helping us to understand, predict and monitor the fate of oil. Despite this, there are many challenges, not least because of the heterogeneity of these ecosystems and the complexity of crude oil. For example, there is growing awareness about the toxicity of the oxygenated products that result from crude-oil weathering, which are difficult to degrade. This review highlights how developments in areas as diverse as systems biology, microbiology, ecology, biogeochemistry and analytical chemistry are enhancing our understanding of hydrocarbon biodegradation and thus bioremediation of oil-polluted intertidal wetlands. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. Old River Control Complex Sedimentation Investigation

    Science.gov (United States)

    2015-06-01

    In an alluvial river, the transport of sediment is tied very closely to the reservoir of sediment available in the sediment bed. Therefore, the...ER D C/ CH L TR -1 5- 8 Old River Control Complex Sedimentation Investigation Co as ta l a nd H yd ra ul ic s La bo ra to ry...acwc.sdp.sirsi.net/client/default. ERDC/CHL TR-15-8 June 2015 Old River Control Complex Sedimentation Investigation Ronald E. Heath, Gary L. Brown

  13. A Sediment Budget Case Study: Comparing Watershed Scale Erosion Estimates to Modeled and Empirical Sediment Loads

    Science.gov (United States)

    McDavitt, B.; O'Connor, M.

    2003-12-01

    The Pacific Lumber Company Habitat Conservation Plan requires watershed analyses to be conducted on their property. This paper summarizes a portion of that analysis focusing on erosion and sedimentation processes and rates coupled with downstream sediment routing in the Freshwater Creek watershed in northwest California. Watershed scale erosion sources from hillslopes, roads, and channel banks were quantified using field surveys, aerial photo interpretation, and empirical modeling approaches for different elements of the study. Sediment transport rates for bedload were modeled, and sediment transport rates for suspended sediment were estimated based on size distribution of sediment inputs in relation to sizes transported in suspension. Recent short-term, high-quality estimates of suspended sediment yield that a community watershed group collected with technical assistance from the US Forest Service were used to validate the resulting sediment budget. Bedload yield data from an adjacent watershed, Jacoby Creek, provided another check on the sediment budget. The sediment budget techniques and bedload routing models used for this study generated sediment yield estimates that are in good agreement with available data. These results suggest that sediment budget techniques that require moderate levels of fieldwork can be used to provide relatively accurate technical assessments. Ongoing monitoring of sediment sources coupled with sediment routing models and reach scale field data allows for predictions to be made regarding in-channel sediment storage.

  14. {sup 137}Cs in marine sediments of Admiralty Bay, King George Island, Antarctica

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Paulo Alves de Lima [Instituto Oceanográfico, Universidade de São Paulo (IO-USP), Pça. do Oceanográfico, 191, Butantã, SP, 05508 900 (Brazil); Ribeiro, Andreza Portella, E-mail: andrezpr@usp.br [Instituto Oceanográfico, Universidade de São Paulo (IO-USP), Pça. do Oceanográfico, 191, Butantã, SP, 05508 900 (Brazil); Mestrado de Gestão Ambiental e Sustentabilidade, Universidade Nove de Julho (UNINOVE), Avenida Francisco Matarazzo, 612, prédio C, andar térreo, Água Branca, São Paulo, SP, 05001 100 (Brazil); Nascimento, Mylene Giseli do; Martins, Cesar de Castro [Centro de Estudos do Mar, Universidade Federal do Paraná (CEM-UFPR), Av. Beira-mar, no number, Balneário Pontal do Sul, Pontal do Paraná, PR, 83255 971 (Brazil); Mahiques, Michel Michaelovitch de; Montone, Rosalinda Carmelo; Figueira, Rubens Cesar Lopes [Instituto Oceanográfico, Universidade de São Paulo (IO-USP), Pça. do Oceanográfico, 191, Butantã, SP, 05508 900 (Brazil)

    2013-01-15

    The radionuclide cesium-137 ({sup 137}Cs) is produced exclusively by anthropogenic processes and primarily by nuclear explosions. This study determined the reference inventory that is {sup 137}Cs associated with the element's original input, and utilized the levels of activity of this radionuclide previously measured in five sediment profiles collected from Admiralty Bay, Antarctica, to investigate the mobility of this element in the environment. {sup 137}Cs has a half-life of 30 years. Because of this, it is environmentally persistent and has been shown to accumulate in marine organisms. The mean reference inventory of this radionuclide in Admiralty Bay sediments, determined using high resolution gamma ray spectrometry, was 20.23 ± 8.94 Bq m{sup −2}, and within the ambient {sup 137}Cs activity range. A model of {sup 137}Cs diffusion–convection was applied to data collected from 1 cm intervals in sediment cores with the aim of providing insights with respect to this element's behavior in sediments. Model results showed a significant correlation between measured and modeled values using the concentrations of {sup 137}Cs, and estimated input into the system from the global fallout of past nuclear tests and expected values based on local sedimentation rates. Results highlight the importance of accounting for the vertical diffusion of {sup 137}Cs in marine sediments when used as a tracer for environmental processes and for assessing potential bioavailability. - Highlights: ► Cesium-137 ({sup 137}Cs) is produced exclusively by anthropogenic processes. ► A model of diffusion–convection simulated {sup 137}Cs environmental behavior. ► This is important for assessing the bioavailability of this toxic element. ► In Antarctica ice cover influenced the input to the sediments.

  15. Potential risks of metal toxicity in contaminated sediments of Deule river in Northern France

    Energy Technology Data Exchange (ETDEWEB)

    Lourino-Cabana, Beatriz; Lesven, Ludovic; Charriau, Adeline [Equipe de Chimie Analytique et Marine, Universite de Lille 1, FRE CNRS Geosystemes 3298, Bat. C8, 59655 Villeneuve d' Ascq (France); Billon, Gabriel, E-mail: gabriel.billon@univ-lille1.fr [Equipe de Chimie Analytique et Marine, Universite de Lille 1, FRE CNRS Geosystemes 3298, Bat. C8, 59655 Villeneuve d' Ascq (France); Ouddane, Baghdad [Equipe de Chimie Analytique et Marine, Universite de Lille 1, FRE CNRS Geosystemes 3298, Bat. C8, 59655 Villeneuve d' Ascq (France); Boughriet, Abdel [Universite Lille Nord de France, Rue de l' Universite, P.O. Box 819, 62408 Bethune (France)

    2011-02-28

    Research highlights: {yields} A historical environmental pollution is evidenced with reference to background levels. {yields} Sedimentary trace metals partitioning is examined under undisturbed conditions. {yields} Anoxia and diagenetic processes induce geochemical and mineralogical variabilities. {yields} Do metals present in particles and pore waters exhibit a potential toxicity risk? {yields} Behaviour of binding fractions contributes to trace metals scavenging. - Abstract: The aim of this paper was to evaluate the potential sediment cumulative damage and toxicity due to metal contamination in a polluted zone of Deule river (in northern France) from nearby two smelters. Metal-enrichment factors and geoaccumulation indices measured with sediment depth revealed that - compared to background levels either in local reference soils or in world rivers sediments/suspended particulate matter - Cd contributed to the highest pollution levels, followed by Zn, Pb and to a much lesser extent Cu and Ni. A comparison of the vertical distribution of AVS (acid volatile sulfides), SEM (simultaneously extracted metals), TMC (total metal concentrations), TOC (total organic carbon) and interstitial water-metal concentrations in the sediment allowed us to highlight the extent of toxicity caused by Cd, Pb, Zn, Ni and Cu and to raise the possibility of their association with certain geochemical phases. To assess the actual environmental impacts of these metals in Deule river, numerical sediment quality guidelines were further used in the present work. Sedimentary Pb, Zn, and Cd contents largely exceeded PEC (probable effect concentration) values reported as consensus-based sediment quality guidelines for freshwater ecosystems. As for risks of toxicity from pore waters, metal concentrations reached their maxima at the surficial layers of the sediment (1-3 cm) and IWCTU (Interstitial Water Criteria Toxicity Unit) observed for Pb and to a lesser extent Cd, violated the corresponding water

  16. Sediment unmixing using detrital geochronology

    Science.gov (United States)

    Sharman, Glenn R.; Johnstone, Samuel

    2017-01-01

    Sediment mixing within sediment routing systems can exert a strong influence on the preservation of provenance signals that yield insight into the influence of environmental forcings (e.g., tectonism, climate) on the earth’s surface. Here we discuss two approaches to unmixing detrital geochronologic data in an effort to characterize complex changes in the sedimentary record. First we summarize ‘top-down’ mixing, which has been successfully employed in the past to characterize the different fractions of prescribed source distributions (‘parents’) that characterize a derived sample or set of samples (‘daughters’). Second we propose the use of ‘bottom-up’ methods, previously used primarily for grain size distributions, to model parent distributions and the abundances of these parents within a set of daughters. We demonstrate the utility of both top-down and bottom-up approaches to unmixing detrital geochronologic data within a well-constrained sediment routing system in central California. Use of a variety of goodness-of-fit metrics in top-down modeling reveals the importance of considering the range of allowable mixtures over any single best-fit mixture calculation. Bottom-up modeling of 12 daughter samples from beaches and submarine canyons yields modeled parent distributions that are remarkably similar to those expected from the geologic context of the sediment-routing system. In general, mixture modeling has potential to supplement more widely applied approaches in comparing detrital geochronologic data by casting differences between samples as differing proportions of geologically meaningful end-member provenance categories.

  17. Monitoring of pollution in sediments

    Directory of Open Access Journals (Sweden)

    Renee I. Abdallah

    2016-03-01

    Full Text Available Polycyclic aromatic hydrocarbons (PAHs and aliphatic hydrocarbons (AHs were analyzed in surface sediments collected from Suez till Hurgharda coasts to establish baseline levels for various types of organic pollutants before the anticipated identification of anthropogenic activities, petrogenic and biogenic. AHs for all samples were dominated by unresolved complex mixture (UCM, and petrogenic mixed with biogenic sources. Results also revealed that sedimentary PAHs mainly originated from pyrolysis sources.

  18. Sediment unmixing using detrital geochronology

    Science.gov (United States)

    Sharman, Glenn R.; Johnstone, Samuel A.

    2017-11-01

    Sediment mixing within sediment routing systems can exert a strong influence on the preservation of provenance signals that yield insight into the effect of environmental forcing (e.g., tectonism, climate) on the Earth's surface. Here, we discuss two approaches to unmixing detrital geochronologic data in an effort to characterize complex changes in the sedimentary record. First, we summarize 'top-down' mixing, which has been successfully employed in the past to characterize the different fractions of prescribed source distributions ('parents') that characterize a derived sample or set of samples ('daughters'). Second, we propose the use of 'bottom-up' methods, previously used primarily for grain size distributions, to model parent distributions and the abundances of these parents within a set of daughters. We demonstrate the utility of both top-down and bottom-up approaches to unmixing detrital geochronologic data within a well-constrained sediment routing system in central California. Use of a variety of goodness-of-fit metrics in top-down modeling reveals the importance of considering the range of allowable that is well mixed over any single best-fit mixture calculation. Bottom-up modeling of 12 daughter samples from beaches and submarine canyons yields modeled parent distributions that are remarkably similar to those expected from the geologic context of the sediment-routing system. In general, mixture modeling has the potential to supplement more widely applied approaches in comparing detrital geochronologic data by casting differences between samples as differing proportions of geologically meaningful end-member provenance categories.

  19. In situ oxygen dynamics and carbon turnover in an intertidal sediment (Skallingen, Denmark)

    DEFF Research Database (Denmark)

    Walpersdorf, Eva Christine; Kühl, Michael; Elberling, Bo

    2017-01-01

    Intertidal areas are considered to be productive habitats, but due to the challenging and dynamic environment, in situ assessments of their performance remain scarce. Here, we aimed to quantify the production and turnover of organic material in an intertidal sediment across several consecutive diel...... activity during the target autumn period was net heterotrophic with an average net ecosystem metabolism of −2.21 (span: −7.93 to 1.48) mmol O2 m−2 d−1. This study highlights the extreme temporal and spatial variation of intertidal sediments and the importance of accounting for natural in situ dynamics...

  20. Coastal hypoxia and sediment biogeochemistry

    Directory of Open Access Journals (Sweden)

    J. J. Middelburg

    2009-07-01

    Full Text Available The intensity, duration and frequency of coastal hypoxia (oxygen concentration <63 μM are increasing due to human alteration of coastal ecosystems and changes in oceanographic conditions due to global warming. Here we provide a concise review of the consequences of coastal hypoxia for sediment biogeochemistry. Changes in bottom-water oxygen levels have consequences for early diagenetic pathways (more anaerobic at expense of aerobic pathways, the efficiency of re-oxidation of reduced metabolites and the nature, direction and magnitude of sediment-water exchange fluxes. Hypoxia may also lead to more organic matter accumulation and burial and the organic matter eventually buried is also of higher quality, i.e. less degraded. Bottom-water oxygen levels also affect the organisms involved in organic matter processing with the contribution of metazoans decreasing as oxygen levels drop. Hypoxia has a significant effect on benthic animals with the consequences that ecosystem functions related to macrofauna such as bio-irrigation and bioturbation are significantly affected by hypoxia as well. Since many microbes and microbial-mediated biogeochemical processes depend on animal-induced transport processes (e.g. re-oxidation of particulate reduced sulphur and denitrification, there are indirect hypoxia effects on biogeochemistry via the benthos. Severe long-lasting hypoxia and anoxia may result in the accumulation of reduced compounds in sediments and elimination of macrobenthic communities with the consequences that biogeochemical properties during trajectories of decreasing and increasing oxygen may be different (hysteresis with consequences for coastal ecosystem dynamics.

  1. Organotin persistence in contaminated marine sediments and porewaters: In situ degradation study using species-specific stable isotopic tracers

    Energy Technology Data Exchange (ETDEWEB)

    Furdek, Martina; Mikac, Nevenka [Division for Marine and Environmental Research, Rudjer Boskovic Institute, Bijenicka 54, Zagreb (Croatia); Bueno, Maite; Tessier, Emmanuel; Cavalheiro, Joana [Laboratoire de Chimie Analytique Bio-inorganique et Environnement, Institut Pluridisciplinaire de Recherche sur l’Environnement et les Matériaux, CNRS UMR 5254, Université de Pau et des Pays de l’Adour, Hélioparc Pau Pyrénées, 2, Av. P. Angot, 64053 Pau Cedex 9 (France); Monperrus, Mathilde, E-mail: mathilde.monperrus@univ-pau.fr [Laboratoire de Chimie Analytique Bio-inorganique et Environnement, Institut Pluridisciplinaire de Recherche sur l’Environnement et les Matériaux, CNRS UMR 5254, Université de Pau et des Pays de l’Adour, Hélioparc Pau Pyrénées, 2, Av. P. Angot, 64053 Pau Cedex 9 (France)

    2016-04-15

    Highlights: • Limiting step in OTC degradation in sediments is their desorption into porewater. • TBT persistence in contaminated sediments increases in sediments rich in organic matter. • DBT does not accumulate in sediments as degradation product of TBT. • TBT and DBT degradation in porewaters occurs with half-lives from 2.9 to 9.2 days. • PhTs degradation is slower than BuTs degradation in oxic porewaters. - Abstract: This paper provides a comprehensive study of the persistence of butyltins and phenyltins in contaminated marine sediments and presents the first data on their degradation potentials in porewaters. The study’s aim was to explain the different degradation efficiencies of organotin compounds (OTC) in contaminated sediments. The transformation processes of OTC in sediments and porewaters were investigated in a field experiment using species-specific, isotopically enriched organotin tracers. Sediment characteristics (organic carbon content and grain size) were determined to elucidate their influence on the degradation processes. The results of this study strongly suggest that a limiting step in OTC degradation in marine sediments is their desorption into porewaters because their degradation in porewaters occurs notably fast with half-lives of 9.2 days for tributyltin (TBT) in oxic porewaters and 2.9 ± 0.1 and 9.1 ± 0.9 days for dibutyltin (DBT) in oxic and anoxic porewaters, respectively. By controlling the desorption process, organic matter influences the TBT degradation efficiency and consequently defines its persistence in contaminated sediments, which thus increases in sediments rich in organic matter.

  2. Calcium isotopes in a proglacial weathering environment: Damma glacier, Switzerland

    Science.gov (United States)

    Hindshaw, Ruth S.; Reynolds, Ben C.; Wiederhold, Jan G.; Kretzschmar, Ruben; Bourdon, Bernard

    2010-05-01

    Calcium is a key element in global biogeochemical cycles. It is an essential nutrient and the dissolution of Ca from silicate minerals is intimately linked to the global carbon cycle. Yet relatively few studies have utilized the potential of stable Ca isotopes to directly investigate (as opposed to using Sr isotopes) processes affecting Ca during initial weathering and subsequent cycling within the ecosystem. The Damma glacier fieldsite (Central Swiss Alps) provides an ideal opportunity to study the early stages of silicate weathering processes and is the site of a larger multidisciplinary research project (BigLink). The catchment is underlain by Central Aar granite, which does not contain detectable carbonates. The Damma is a small, glacial catchment (10.7 km2) where the glacier has retreatred since 1850 creating a 1.5 km long chronosequence which spans approximately 150 years of soil development and exhibits a strong vegetation gradient along its length. In order to investigate the biogeochemical Ca cycle in the forefield, extensive sampling of the main reservoirs of Ca was undertaken. Soil samples from two different depths (0-5 and 5-10 cm) were collected at 23 randomly selected sites across the forefield in addition to six bulk rock samples. To further investigate potential fractionation between different soil pools, sequential extractions were performed. Stream water was collected at three different locations in the forefield on a biweekly basis throughout the sampling season, in addition to precipitation (snow and rain) and porewater samples. To investigate the effect of biological cycling on Ca, leaves from Rhododendron ferrugineum were also analysed. Analyses of all samples were performed using a Triton TIMS with a 43Ca-46Ca double spike, after a 4-step chromatographic separation procedure. During this very early stage of weathering, the young soils which have formed were isotopically identical in δ44-42Ca to the rock from which they were derived, indicating that primary dissolution of the bulk rock does not strongly fractionate Ca isotopes. This is further corroborated by the analyses of the streamwaters which were within error of the average soil. Only one time point, coinciding with the end of the main snow melt period, was significantly different in δ44-42Ca from bulk rock. The only Ca pool which was significantly fractionated from bulk rock was vegetation, which exhibited an enrichment of light Ca isotopes. Significant calcium isotope fractionation between bulk rock and soils is likely to only occur where the soils are no longer buffered by primary mineral dissolution and secondary processes such as biological cycling and secondary mineral precipitation become dominant.

  3. Physical properties of muddy sediments from French Guiana

    Science.gov (United States)

    Caillaud, J.; Lesourd, L.; Philippe, S.; Gontharet, S.; Sarrazin, M.; Gardel, A.

    2017-01-01

    The North West migration of long and discontinuous mud banks along the French Guiana coast has been extensively studied during the past years, in particular with a large-scale vision, which consequently has integrated morpho and hydrodynamic data. The aims of the present paper were to use intrinsic sediment properties (grain-size, mineralogy, concentration, and cohesion) to (1) highlight the sedimentary conditions during the consolidation processes from fluid deposit to vegetation development, and (2) verify the apparent homogeneously derived sedimentary facies. Two intertidal transects, Macouria and Cayenne, were compared from the coast to offshore. Their altitude averages of 1 m and 2.8 m above mean sea level, respectively, were different enough to compare the influence of the hydrodynamic impact and emersion time on their sediment properties. The latter, i.e. grain size distribution, mineralogical content, mud concentration, and shear strength (cohesion), were determined from sampled surface sediments (first cm) and along sediment cores (20-30 cm depth) from each transect. A specific X-ray technique was applied to the whole core to differentiate clearly its thin layers. On both intertidal sites, the grain size dominated by the fine silt fraction (2-20 μm) and the bulk mineralogy characterized by five major minerals (quartz, feldspars, chlorite, illite, and kaolinite) appeared homogeneous along both transects and cores. In spite of this apparent uniformity of particle size and mineralogical parameters, as well as for visual observation along the core, high precision X-rays still showed a cyclic sedimentation at a micro-scale level. This cyclicity with intercalation of fine layers was related to distinct dynamic deposits marked by both tidal processes and hydrodynamic factors (swell propagation). The cohesion and concentration results were dependent on the topography, where high topography was characterized by sediments with high cohesion and concentration values

  4. Glider observations and modeling of sediment transport in Hurricane Sandy

    Science.gov (United States)

    Miles, Travis; Seroka, Greg; Kohut, Josh; Schofield, Oscar; Glenn, Scott

    2015-03-01

    Regional sediment resuspension and transport are examined as Hurricane Sandy made landfall on the Mid-Atlantic Bight (MAB) in October 2012. A Teledyne-Webb Slocum glider, equipped with a Nortek Aquadopp current profiler, was deployed on the continental shelf ahead of the storm, and is used to validate sediment transport routines coupled to the Regional Ocean Modeling System (ROMS). The glider was deployed on 25 October, 5 days before Sandy made landfall in southern New Jersey (NJ) and flew along the 40 m isobath south of the Hudson Shelf Valley. We used optical and acoustic backscatter to compare with two modeled size classes along the glider track, 0.1 and 0.4 mm sand, respectively. Observations and modeling revealed full water column resuspension for both size classes for over 24 h during peak waves and currents, with transport oriented along-shelf toward the southwest. Regional model predictions showed over 3 cm of sediment eroded on the northern portion of the NJ shelf where waves and currents were the highest. As the storm passed and winds reversed from onshore to offshore on the southern portion of the domain waves and subsequently orbital velocities necessary for resuspension were reduced leading to over 3 cm of deposition across the entire shelf, just north of Delaware Bay. This study highlights the utility of gliders as a new asset in support of the development and verification of regional sediment resuspension and transport models, particularly during large tropical and extratropical cyclones when in situ data sets are not readily available.

  5. The impact of sediment bioturbation by secondary organisms on metal bioavailability, bioaccumulation and toxicity to target organisms in benthic bioassays: Implications for sediment quality assessment.

    Science.gov (United States)

    Remaili, Timothy M; Simpson, Stuart L; Amato, Elvio D; Spadaro, David A; Jarolimek, Chad V; Jolley, Dianne F

    2016-01-01

    Bioturbation alters the properties of sediments and modifies contaminant bioavailability to benthic organisms. These naturally occurring disturbances are seldom considered during the assessment of sediment quality. We investigated how the presence (High bioturbation) and absence (Low bioturbation) of a strongly bioturbating amphipod within three different sediments influenced metal bioavailability, survival and bioaccumulation of metals to the bivalve Tellina deltoidalis. The concentrations of dissolved copper decreased and manganese increased with increased bioturbation. For copper a strong correlation was observed between increased bivalve survival (53-100%) and dissolved concentrations in the overlying water. Increased bioturbation intensity resulted in greater tissue concentrations for chromium and zinc in some test sediments. Overall, the results highlight the strong influence that the natural bioturbation activities from one organism may have on the risk contaminants pose to other organisms within the local environment. The characterisation of field-based exposure conditions concerning the biotic or abiotic resuspension of sediments and the rate of attenuation of released contaminants through dilution or readsorption may enable laboratory-based bioassay designs to be adapted to better match those of the assessed environment. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Nearshore sediment thickness, Fire Island, New York

    Science.gov (United States)

    Locker, Stanley D.; Miselis, Jennifer L.; Buster, Noreen A.; Hapke, Cheryl J.; Wadman, Heidi M.; McNinch, Jesse E.; Forde, Arnell S.; Stalk, Chelsea A.

    2017-04-03

    Investigations of coastal change at Fire Island, New York (N.Y.), sought to characterize sediment budgets and determine geologic framework controls on coastal processes. Nearshore sediment thickness is critical for assessing coastal system sediment availability, but it is largely unquantified due to the difficulty of conducting geological or geophysical surveys across the nearshore. This study used an amphibious vessel to acquire chirp subbottom profiles. These profiles were used to characterize nearshore geology and provide an assessment of nearshore sediment volume. Two resulting sediment-thickness maps are provided: total Holocene sediment thickness and the thickness of the active shoreface. The Holocene sediment section represents deposition above the maximum flooding surface that is related to the most recent marine transgression. The active shoreface section is the uppermost Holocene sediment, which is interpreted to represent the portion of the shoreface thought to contribute to present and future coastal behavior. The sediment distribution patterns correspond to previously defined zones of erosion, accretion, and stability along the island, demonstrating the importance of sediment availability in the coastal response to storms and seasonal variability. The eastern zone has a thin nearshore sediment thickness, except for an ebb-tidal deposit at the wilderness breach caused by Hurricane Sandy. Thicker sediment is found along a central zone that includes shoreface-attached sand ridges, which is consistent with a stable or accretional coastline in this area. The thickest overall Holocene section is found in the western zone of the study, where a thicker lower section of Holocene sediment appears related to the westward migration of Fire Island Inlet over several hundred years.

  7. Sediment supply versus local hydraulic controls on sediment transport and storage in a river with large sediment loads

    Science.gov (United States)

    Dean, David J.; Topping, David J.; Schmidt, John C.; Griffiths, Ronald E.; Sabol, Thomas A.

    2016-01-01

    The Rio Grande in the Big Bend region of Texas, USA, and Chihuahua and Coahuila, Mexico, undergoes rapid geomorphic changes as a result of its large sediment supply and variable hydrology; thus, it is a useful natural laboratory to investigate the relative importance of flow strength and sediment supply in controlling alluvial channel change. We analyzed a suite of sediment transport and geomorphic data to determine the cumulative influence of different flood types on changing channel form. In this study, physically based analyses suggest that channel change in the Rio Grande is controlled by both changes in flow strength and sediment supply over different spatial and temporal scales. Channel narrowing is primarily caused by substantial deposition of sediment supplied to the Rio Grande during tributary-sourced flash floods. Tributary floods have large suspended-sediment concentrations, occur for short durations, and attenuate rapidly downstream in the Rio Grande, depositing much of their sediment in downstream reaches. Long-duration floods on the mainstem have the capacity to enlarge the Rio Grande, and these floods, released from upstream dams, can either erode or deposit sediment in the Rio Grande depending upon the antecedent in-channel sediment supply and the magnitude and duration of the flood. Geomorphic and sediment transport analyses show that the locations and rates of sand erosion and deposition during long-duration floods are most strongly controlled by spatial changes in flow strength, largely through changes in channel slope. However, spatial differences in the in-channel sediment supply regulate sediment evacuation or accumulation over time in long reaches (greater than a kilometer).

  8. Clonal growth strategy, diversity and structure: A spatiotemporal response to sedimentation in tropical Cyperus papyrus swamps.

    Science.gov (United States)

    Geremew, Addisie; Stiers, Iris; Sierens, Tim; Kefalew, Alemayehu; Triest, Ludwig

    2018-01-01

    Land degradation and soil erosion in the upper catchments of tropical lakes fringed by papyrus vegetation can result in a sediment load gradient from land to lakeward. Understanding the dynamics of clonal modules (ramets and genets) and growth strategies of plants on such a gradient in both space and time is critical for exploring a species adaptation and processes regulating population structure and differentiation. We assessed the spatial and temporal dynamics in clonal growth, diversity, and structure of an emergent macrophyte, Cyperus papyrus (papyrus), in response to two contrasting sedimentation regimes by combining morphological traits and genotype data using 20 microsatellite markers. A total of 636 ramets from six permanent plots (18 x 30 m) in three Ethiopian papyrus swamps, each with discrete sedimentation regimes (high vs. low) were sampled for two years. We found that ramets under the high sedimentation regime (HSR) were significantly clumped and denser than the sparse and spreading ramets under the low sedimentation regime (LSR). The HSR resulted in significantly different ramets with short culm height and girth diameter as compared to the LSR. These results indicated that C. papyrus ameliorates the effect of sedimentation by shifting clonal growth strategy from guerrilla (in LSR) to phalanx (in HSR). Clonal richness, size, dominance, and clonal subrange differed significantly between sediment regimes and studied time periods. Each swamp under HSR revealed a significantly high clonal richness (R = 0.80) as compared to the LSR (R = 0.48). Such discrepancy in clonal richness reflected the occurrence of initial and repeated seedling recruitment strategies as a response to different sedimentation regimes. Overall, our spatial and short-term temporal observations highlighted that HSR enhances clonal richness and decreases clonal subrange owing to repeated seedling recruitment and genets turnover.

  9. Clonal growth strategy, diversity and structure: A spatiotemporal response to sedimentation in tropical Cyperus papyrus swamps.

    Directory of Open Access Journals (Sweden)

    Addisie Geremew

    Full Text Available Land degradation and soil erosion in the upper catchments of tropical lakes fringed by papyrus vegetation can result in a sediment load gradient from land to lakeward. Understanding the dynamics of clonal modules (ramets and genets and growth strategies of plants on such a gradient in both space and time is critical for exploring a species adaptation and processes regulating population structure and differentiation. We assessed the spatial and temporal dynamics in clonal growth, diversity, and structure of an emergent macrophyte, Cyperus papyrus (papyrus, in response to two contrasting sedimentation regimes by combining morphological traits and genotype data using 20 microsatellite markers. A total of 636 ramets from six permanent plots (18 x 30 m in three Ethiopian papyrus swamps, each with discrete sedimentation regimes (high vs. low were sampled for two years. We found that ramets under the high sedimentation regime (HSR were significantly clumped and denser than the sparse and spreading ramets under the low sedimentation regime (LSR. The HSR resulted in significantly different ramets with short culm height and girth diameter as compared to the LSR. These results indicated that C. papyrus ameliorates the effect of sedimentation by shifting clonal growth strategy from guerrilla (in LSR to phalanx (in HSR. Clonal richness, size, dominance, and clonal subrange differed significantly between sediment regimes and studied time periods. Each swamp under HSR revealed a significantly high clonal richness (R = 0.80 as compared to the LSR (R = 0.48. Such discrepancy in clonal richness reflected the occurrence of initial and repeated seedling recruitment strategies as a response to different sedimentation regimes. Overall, our spatial and short-term temporal observations highlighted that HSR enhances clonal richness and decreases clonal subrange owing to repeated seedling recruitment and genets turnover.

  10. Estuarine Suspended Sediment Dynamics: Observations Derived from over a Decade of Satellite Data

    Directory of Open Access Journals (Sweden)

    Anthony Reisinger

    2017-12-01

    Full Text Available Suspended sediment dynamics of Corpus Christi Bay, Texas, USA, a shallow-water wind-driven estuary, were investigated by combining field and satellite measurements of total suspended solids (TSS. An algorithm was developed to transform 500-m Moderate Resolution Imaging Spectroradiometer (MODIS Aqua satellite reflectance data into estimated TSS values. The algorithm was developed using a reflectance ratio regression of MODIS Band 1 (red and Band 3 (green with TSS measurements (n = 54 collected by the Texas Commission on Environmental Quality for Corpus Christi Bay and other Texas estuaries. The algorithm was validated by independently collected TSS measurements during the period of 2011–2014 with an uncertainty estimate of 13%. The algorithm was applied to the period of 2002–2014 to create a synoptic time series of TSS for Corpus Christi Bay. Potential drivers of long-term variability in suspended sediment were investigated. Median and IQR composites of suspended sediments were generated for seasonal wind regimes. From this analysis it was determined that long-term, spatial patterns of suspended sediment in the estuary are related to wind-wave resuspension during the predominant northerly and prevalent southeasterly seasonal wind regimes. The impact of dredging is also apparent in long-term patterns of Corpus Christi Bay as concentrations of suspended sediments over dredge spoil disposal sites are higher and more variable than surrounding areas, which is most likely due to their less consolidated sediments and shallower depths requiring less wave energy for sediment resuspension. This study highlights the advantage of how long-synoptic time series of TSS can be used to elucidate the major drivers of suspended sediments in estuaries.

  11. Source identification of fine-grained suspended sediment in the Kharaa River basin, northern Mongolia

    Energy Technology Data Exchange (ETDEWEB)

    Theuring, Philipp [Department of Aquatic Ecosystem Analysis and Management — ASAM, Helmholtz Centre for Environmental Research — UFZ, Brückstrasse 3a, D-39114 Magdeburg (Germany); Collins, Adrian L. [Sustainable Soils and Grassland Systems Department, Rothamsted Research, North Wyke, Okehampton, Devon EX20 2SB (United Kingdom); Rode, Michael [Department of Aquatic Ecosystem Analysis and Management — ASAM, Helmholtz Centre for Environmental Research — UFZ, Brückstrasse 3a, D-39114 Magdeburg (Germany)

    2015-09-01

    Fine sediment inputs into river systems can be a major source of nutrients and heavy metals and have a strong impact on water quality and ecosystem functions of rivers and lakes, including those in semiarid regions. However, little is known to date about the spatial distribution of sediment sources in most large scale river basins in Central Asia. Accordingly, a sediment source fingerprinting technique was used to assess the spatial sources of fine-grained (< 10 μm) sediment in the 15 000 km{sup 2} Kharaa River basin in northern Mongolia. Variation in geochemical composition (e.g. in Ti, Sn, Mo, Mn, As, Sr, B, U, Ca and Sb) was used for sediment source discrimination with geochemical composite fingerprints based on Genetic Algorithm (GA)-driven Discriminant Function Analysis, the Kruskal–Wallis H-test and Principal Component Analysis. All composite fingerprints yielded a satisfactory GOF (> 0.97) and were subsequently used for numerical mass balance modelling with uncertainty analysis. The contributions of the individual sub-catchment spatial sediment sources varied from 6.4% (the headwater sub-catchment of Sugnugur Gol) to 36.2% (the Kharaa II sub-catchment in the middle reaches of the study basin), generally showing higher contributions from the sub-catchments in the middle, rather than the upstream, portions of the study area. The importance of river bank erosion is shown to increase from upstream to midstream tributaries. The source tracing procedure provides results in reasonable accordance with previous findings in the study region and demonstrates the applicability and associated uncertainties of the approach for fine-grained sediment source investigation in large scale semi-arid catchments. - Highlights: • Applied statistical approach for selecting composite fingerprints in Mongolia. • Geochemical fingerprinting for the definition of source areas in semiarid catchment. • Test of applicability of sediment sourcing in large scale semi-arid catchments

  12. Sediments deposition due to soil erosion in the watershed region of Mangla dam.

    Science.gov (United States)

    Butt, Mohsin Jamil; Mahmood, Rashed; Waqas, Ahmad

    2011-10-01

    Soil erosion is the most important reason of sedimentation load of water reservoirs in the world. In Pakistan, Mangla dam is one of the most important water reservoirs used for the production of electricity and for the supply of water for irrigation purposes. However, the capacity of Mangla dam reservoir has reduced by more than 20% since its construction. This study highlights the impact of rainfall on soil erosion and consequently on sedimentation deposition in Mangla dam reservoir. Sedimentation, annual rainfall, and normal rainfall data of 39 years were used in this study. Shuttle Radar Topographic Mission data were used to calculate the total drainage area of the Mangla watershed region. The sedimentation data of Mangla reservoir from 1967 to 2005 were retrieved from Water and Power Development Authority in Pakistan. The meteorological observatories in the Mangla watershed region are identified. Annual rainfall data from 1967 to 2005 for the meteorological observatories in the Mangla watershed regions were retrieved from Pakistan Meteorological Department (PMD). In addition, normal rainfall data for the years 1949 to 1978 and for the years 1979 to 2008 were also retrieved from PMD. The impact of annual rainfall is observed on sedimentation load in Mangla dam. The correlation coefficient between annual rainfall and sedimentation load is 0.94. This study shows that with an increase in rainfall, the soil erosion of the area increases which subsequently is responsible for the increase in the rate of sedimentation load in Mangla dam. This study further demonstrates that better soil management can reduce the sedimentation load in the Mangla reservoir.

  13. The use of novel wooden structures to manage flooding and coarse sediment problems in responsive upland headwater catchments

    Science.gov (United States)

    Wilkinson, Mark; Addy, Steve; Ghimire, Sohan; Watson, Helen; Stutter, Marc

    2014-05-01

    Over the past decade economic losses from floods have greatly increased, with sediment related impacts as a key feature of such events. Impacts include changes in river channel course, scour of river banks, sedimentation of infrastructure (e.g. bridges), and deposition of sand and gravel on farmland. Sediment deposition can in turn reduce conveyance capacity and lead to further increased flood risk. The EU Water Framework Directive and Floods Directive highlights that sustainable approaches to flood risk reduction should be used alongside and, where possible, replace traditional structural flood defences and activities that address sediment problems. Natural Flood Management(NFM) is promoted as a method that can reduce flood risk and manage sediment by incorporating natural hydrological and morphological processes. As such, NFM measures are designed to use these fluvial processes to manage the sources and pathways of flood waters and sediments. Techniques include the restoration, enhancement and alteration of natural features and characteristics, but exclude traditional flood defence engineering that works against or disrupts these natural processes. Here we aim to assess the effectiveness of novel flood mitigation measures for reducing flood risk and capturing coarse sediment in rapidly responding headwater catchments. We present preliminary research findings from a densely instrumented research site (Bowmont catchment, Scotland (85km2)) which regularly experiences flood events with associated coarse sediment problems. NFM measures have been installed to capture course sediment and to store water more effectively on the flood plains during these flood events. For example, novel engineered wooden structures ('bar apex log jams') constructed in the river corridor are designed to trap sediment and log bank protection structures have been installed to stop bank erosion. Within a tributary catchment of the Bowmont (0.7km2), new flow restrictors have been installed on a

  14. On luminescence bleaching of tidal channel sediments

    DEFF Research Database (Denmark)

    Fruergaard, Mikkel; Pejrup, Morten; Murray, Andrew S.

    2015-01-01

    We investigate the processes responsible for bleaching of the quartz OSL signal from tidal channel sediment. Tidal dynamics are expected to play an important role for complete bleaching of tidal sediments. However, no studies have examined the amount of reworking occurring in tidal channels...... and on tidal flats due to the mixing caused by currents and waves. We apply bed level data to evaluate the amount of vertical sediment reworking in modern tidal channels and at a tidal flat. Cycles of deposition and erosion are measured with a bed level sensor, and the results show that gross sedimentation...... was several times higher than net sedimentation. We propose that tidal channel sediment is bleached either on the tidal flat before it is transported to the tidal channels and incorporated in channel-fill successions or, alternatively, on the shallow intertidal part of the channel banks. Based...

  15. Sediment measurement in estuarine and coastal areas

    Science.gov (United States)

    Shelley, P. E.

    1976-01-01

    A survey of uses of estuarine and coastal areas is given. Problems associated with these uses are discussed, and data needs for intelligent management of these valuable areas are outlined. Suspended sediment measurements are seen to be one of the greatest needs. To help understand the complexity of the problem, a brief discussion of sediment mechanics is given, including sediment sources, characteristics, and transport. The impact of sediment mechanics on its direct measurement (sampling and analysis) is indicated, along with recommendations for directly obtaining representative data. Indirect measurement of suspended sediment by remote sensors is discussed both theoretically and in the light of some recent experiences. The need for an integrated, multidisciplinary program to solve the problem of quantitatively measuring suspended sediment with remote sensors is stressed, and several important considerations of such a program and benefits to be derived therefrom are briefly addressed.

  16. Sulfate reduction and methanogenesis in marine sediments

    Science.gov (United States)

    Oremland, R. S.; Taylor, B. F.

    1978-01-01

    Methanogenesis and sulfate-reduction were followed in laboratory incubations of sediments taken from tropical seagrass beds. Methanogenesis and sulfate-reduction occurred simultaneously in sediments incubated under N2, thereby indicating that the two processes are not mutually exclusive. Sediments incubated under an atmosphere of H2 developed negative pressures due to the oxidation of H2 by sulfate-respiring bacteria. H2 also stimulated methanogenesis, but methanogenic bacteria could not compete for H2 with the sulfate-respiring bacteria.

  17. Analysis of sedimentation of canals

    Directory of Open Access Journals (Sweden)

    Agunwamba, J.C.,

    2013-03-01

    Full Text Available The dredged canals in the Niger Delta coastal flood plain are being threatened by siltation. This study is limited to those canals in Rivers State of Nigeria, which are under the influence of tidal waves. A total of eight canals were considered with four each from Ekulama and Cawthorne Channel. Different approaches were used to carry out this study, which includes field reconnaissance survey, hydrographic survey, soil sample analysis and collection of all available data and information. The typical bed materials size (D50 is approximately 0.01mm; which gives a settling velocity of 0.09mm/sec using stroke’s law. Hydrographic survey of the canals from 1992 to 1996 revealed an average siltation rate of 2.35m/yr. A regression equation was also derived which relates the cost of dredging to canal area, rate of siltation and average aggregation. A plot of canal centre profile; entrance, middle and end cross sections showing sediment distribution along the canal profile, shows that majority of the particles that form the sediment enter the canal from the rivers. The sedimentation is caused by the reduction in water current, which has average value of 0.0145m/sec. The bathyorographical check on the canals revealed that the sum of the two exterior angles of the canal with the river at the point of connection has to lie within 1800 + 50 for an effective flow that will minimize settlement of particles. In addition, the canals should be constructed to start and terminate on a moving water body, to avoid dead ends. A regression equation was determined which relates the cost of dredging to canal area, rate of siltation and average aggradations.

  18. Dewatering of contaminated river sediments

    Science.gov (United States)

    Church, Ronald H.; Smith, Carl W.; Scheiner, Bernard J.

    1994-01-01

    Dewatering of slurries has been successfully accomplished by the proper use of polymers in flocculating the fine particulate matter suspended in mineral processing streams. The U.S. Bureau of Mines (USBM) entered into a cooperative research effort with the U.S. Army Corps of Engineers (Corps) for the purpose of testing and demonstrating the applicability of mining flocculation technology to dredging activities associated with the removal of sediments from navigable waterways. The Corps has the responsibility for maintaining the navigable waterways in the United States. Current technology relies primarily on dredging operations which excavate the material from the bottom of waterways. The Corps is testing new dredging technology which may reduce resuspension of sediments by the dredging operation. Pilot plant dredging equipment was tested by the Corps which generated larger quantities of water when compared to conventional equipment, such as the clam shell. The transportation of this 'excess' water adds to the cost of sediment removal. The process developed by the USBM consists of feed material from the barge being pumped through a 4-in line by a centrifugal pump and exiting through a 4-in PVC delivery system. A 1,000-gal fiberglass tank was used to mix the polymer concentrate. The polymer was pumped through a 1-in line using a variable speed progressive cavity pump and introduced to the 4-in feed line prior to passing through a 6-in by 2-ft static mixer. The polymer/feed slurry travels to the clarifying tank where the flocculated material settled to the bottom and allowed 'clean' water to exit the overflow. A pilot scale flocculation unit was operated on-site at the Corps' 'Confined Disposal Facility' in Buffalo, NY.

  19. Sedimentation

    Digital Repository Service at National Institute of Oceanography (India)

    Rixen, T.; Guptha, M.V.S.; Ittekkot, V.

    by a factor two in Arabian Sea. The organic carbon burial rates in Arabian Sea related to primary production and carbonate accumulation reveal an acceptable agreement on a global scale except at sea floor spreading zones and continental margins....

  20. Rapid Sediment Characterization of PCB With Elisa: An Immunoassay Technique a Rapid Sediment Characterization (RSC) Tool

    National Research Council Canada - National Science Library

    Ta, Nick

    2001-01-01

    ...) immunoassay test kits for screening of PCBs in sediment samples. Traditional sampling and analysis methods of marine ecosystems, namely sediment, do not always provide the information needed in a timely and cost effective manner...

  1. Anthropogenic effects on sediment quality offshore southwestern Taiwan: Assessing the sediment core geochemical record

    Digital Repository Service at National Institute of Oceanography (India)

    Selvaraj, K.; Parthiban, G.; Chen, C.T.A.; Lou, J.Y.

    Slag material was dumped in two sites off southwestern Taiwan by the China Steel Corporation during 1984-1995. By geochemically analyzing four sediment cores, the impact of slag on the sediment chemistry is investigated. Elemental profiles from...

  2. Origin of Stability in Sedimentation

    Science.gov (United States)

    Segre, P. N.

    2003-01-01

    Velocity fluctuations and particle concentrations are studied in a liquid fluidized bed to investigate the origin of steady state sedimentation. Both the velocity fluctuations and the particle concentrations are found to strongly depend on height. A flux balance model shows why the bed is stable: velocity fluctuations drive a downward particle flux that is compensated by an upward particle flux stemming from an excess flow velocity due to the stratification in concentration. Our results show that in steady state the magnitudes of the fluctuations are related to the degree of stratification.

  3. Chronology and processes of late Quaternary hillslope sedimentation in the eastern South Island, New Zealand

    DEFF Research Database (Denmark)

    Borella, Josh; Quigley, Mark; Sohbati, Reza

    2016-01-01

    Optical and radiocarbon dating of loessic hillslope sediments in New Zealand’s South Island is used to constrain the timing of prehistoric rockfalls and associated seismic events, and quantify spatial and temporal patterns of hillslope sedimentation including responses to seismic and anthropogenic...... of Polynesians (ca. AD 1280) and Europeans (ca. AD 1800) in New Zealand, and suggest loess accumulation was continuing at the study site until 12–13 ka. Large (>5m3) prehistoric rockfall boulders preserve an important record of Holocene hillslope sedimentation by creating local traps (i.e. accommodation space......-mantled hillslopes in New Zealand’s South Island into a longer temporal framework and highlights the roles of earthquakes and humans on hillslope surface process....

  4. Leaching properties of estuarine harbor sediment before and after electrodialytic remediation

    DEFF Research Database (Denmark)

    Gardner, Kevin H.; Nystrøm, Gunvor Marie; Aulisio, D.A.

    2007-01-01

    . pH-dependent leaching tests were used to evaluate changes in leaching properties of treated and control sediments. Significant fractions of total concentrations were removed during treatment (35-95% with an average of 75% for all sediments and elements investigated). The release of elements in p......H-dependent leaching tests, however, demonstrated equal or greater leaching from treated sediments in the neutral pH range. Dissolved organic carbon appears to be a significant contributor to post-treatment increases in leaching, and dissolution of significant iron and aluminum sorption sites is hypothesized to also...... play a role. This research highlights the importance of understanding contaminant speciation and availability, as total metals concentrations, in this particular case, do not relate to estimates of the environmental availability of metals (total concentrations were typically two to three orders...

  5. Chlorobiphenhyls in marine sediments: guidelines for determination

    National Research Council Canada - National Science Library

    Smedes, F; de Boer, J

    1998-01-01

    The analysis of chlorinated biphenyls in sediments generally includes extraction with organic solvents, clean-up, removal of sulphur, column fractionation and gas chromatographic separation, mostly...

  6. Reservoir Sedimentation Based on Uncertainty Analysis

    Directory of Open Access Journals (Sweden)

    Farhad Imanshoar

    2014-01-01

    Full Text Available Reservoir sedimentation can result in loss of much needed reservoir storage capacity, reducing the useful life of dams. Thus, sufficient sediment storage capacity should be provided for the reservoir design stage to ensure that sediment accumulation will not impair the functioning of the reservoir during the useful operational-economic life of the project. However, an important issue to consider when estimating reservoir sedimentation and accumulation is the uncertainty involved in reservoir sedimentation. In this paper, the basic factors influencing the density of sediments deposited in reservoirs are discussed, and uncertainties in reservoir sedimentation have been determined using the Delta method. Further, Kenny Reservoir in the White River Basin in northwestern Colorado was selected to determine the density of deposits in the reservoir and the coefficient of variation. The results of this investigation have indicated that by using the Delta method in the case of Kenny Reservoir, the uncertainty regarding accumulated sediment density, expressed by the coefficient of variation for a period of 50 years of reservoir operation, could be reduced to about 10%. Results of the Delta method suggest an applicable approach for dead storage planning via interfacing with uncertainties associated with reservoir sedimentation.

  7. Suspended sediments limit coral sperm availability

    Science.gov (United States)

    Ricardo, Gerard F.; Jones, Ross J.; Clode, Peta L.; Humanes, Adriana; Negri, Andrew P.

    2015-01-01

    Suspended sediment from dredging activities and natural resuspension events represent a risk to the reproductive processes of coral, and therefore the ongoing maintenance of reefal populations. To investigate the underlying mechanisms that could reduce the fertilisation success in turbid water, we conducted several experiments exposing gametes of the corals Acropora tenuis and A. millepora to two sediment types. Sperm limitation was identified in the presence of siliciclastic sediment (230 and ~700 mg L−1), with 2–37 fold more sperm required to achieve maximum fertilisation rates, when compared with sediment-free treatments. This effect was more pronounced at sub-optimum sperm concentrations. Considerable (>45%) decreases in sperm concentration at the water’s surface was recorded in the presence of siliciclastic sediment and a >20% decrease for carbonate sediment. Electron microscopy then confirmed sediment entangled sperm and we propose entrapment and sinking is the primary mechanism reducing sperm available to the egg. Longer exposure to suspended sediments and gamete aging further decreased fertilisation success when compared with a shorter exposure. Collectively, these findings demonstrate that high concentrations of suspended sediments effectively remove sperm from the water’s surface during coral spawning events, reducing the window for fertilisation with potential subsequent flow-on effects for recruitment. PMID:26659008

  8. Sediment reservoirs and sediment fluxes in high mountain environments: how does sediment move through the system at the decadal scale?

    Science.gov (United States)

    Micheletti, Natan; Lambiel, Christophe; Lane, Stuart N.

    2016-04-01

    Faced with rapid climate warming over recent decades, high mountain systems are likely to respond dramatically because of: (1) the vulnerability of permafrost, glacial and nival processes to temperature and precipitation changes; (2) the ample availability of unconsolidated, potentially mobile sediments left after deglaciation; and (3) steep slopes, that potentially aid sediment mobilization. We no surprisingly know little about these processes over the decadal scale because the geomorphic response is often complex, spatially and temporally, and there is little history of decadal scale measurement of these systems. In this paper, we focus upon a number of basins in the Southern Swiss Alps, with a wide range of primary sediment transfer mechanisms and altitude ranges up to 1,800 to 3,600 m asl. We are able to combine a set of unique data on: (1) erosion/deposition processes (derived from combined geomorphological maps and photogrammetrically-derived Digital Elevation Models); (2) sediment flux based upon tracking sediment using image correlation; (3) sediment connection quantified using a new approach to handle DEM noise; (4) changing stream sediment transport capacity derived from hydrodynamic modeling applied to long time series of river flow; and (5) sediment export measured at intakes flushed periodically as part of hydropower management. Results suggest a distinct landscape response to climatic forcing. A progressive acceleration of surface displacements for different landforms is observed throughout the last five decades. We observed that, with the beginning of a warmer period in the 1980s, glacier retreat and enhanced snowmelt caused water yield to increase considerably for various watersheds. This translates into enhancement of sediment transport capacities, which in combination with the intensification of landscape dynamics (greater erosion rates) explains the increase flushing frequency and hence sediment export registered in the basins. However, whilst

  9. Impact of sediments resuspension on metal solubilization and water quality during recurrent reservoir sluicing management

    Energy Technology Data Exchange (ETDEWEB)

    Frémion, Franck; Courtin-Nomade, Alexandra [Groupement de Recherche Eau Sol Environnement, Université de Limoges, 123 avenue Albert Thomas, 87060 Limoges Cedex (France); Bordas, François, E-mail: francois.bordas@unilim.fr [Groupement de Recherche Eau Sol Environnement, Université de Limoges, 123 avenue Albert Thomas, 87060 Limoges Cedex (France); Lenain, Jean-François [Groupement de Recherche Eau Sol Environnement, Université de Limoges, 123 avenue Albert Thomas, 87060 Limoges Cedex (France); Jugé, Philippe [CETU – ELMIS Ingénieries, Université François Rabelais, , 60 Rue du Plat d' Étain, 37000 Tours (France); Kestens, Tim [EDF – DPIH, Unité de Production Centre, 19 bis avenue de la Révolution, BP 406, 87012 Limoges Cedex (France); Mourier, Brice [Groupement de Recherche Eau Sol Environnement, Université de Limoges, 123 avenue Albert Thomas, 87060 Limoges Cedex (France)

    2016-08-15

    In dam contexts, sluicing operations can be performed to reestablish sediments continuity, as proposed by the EU Water Framework Directive, as well as to preserve the reservoirs' water storage capacity. Such management permits the rapid release of high quantities of reservoir sediments through the opening of dam bottom valves. This work aims to study the impact of such operation on the evolution of environmental physicochemical conditions notably changes in dissolved metallic elements concentrations (Al, As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Zn) through field and laboratory investigations. Results were interpreted in terms of concentrations and fluxes, and compared with data collected on an annual basis regarding both suspended matter and metallic elements. The release of high quantities of sediments (4,500 tons dry weight in 24 h), with concentrations representing up to 300 times the inter-annual mean suspended sediments discharge, significantly modified water parameters, notably solid/liquid (S/L) ratio, pH and redox conditions. Despite the fact that they are mainly trapped in stable phases, a clear increase of the solubilized metals content was measured, representing up to 60 times the maximum values of current exploitation. This solubilization is related to desorption phenomena from sediments through changes in chemical equilibriums as highlighted by laboratory characterizations and experiments. These chemical modifications are mainly attributed to S/L ratio variations. Indeed, the low S/L ratios (≤ 1.3 g·L{sup −1}) measured in situ are typically the ones for which metals solubilization is the highest, as shown by laboratory experiments. Additional thermodynamic modeling highlighted that the decrease in pH measured during the operation favors the release of the free forms of metallic elements (Al and Cu), and decreases the OM complexation influence. These changes, either in term of physical conditions or speciation, increasing metals long term

  10. Hawaii Regional Sediment Management: Regional Sediment Budget for the Poipu Region of Kauai, HI

    Science.gov (United States)

    2013-06-01

    Beach cell consists of primarily terrigenous sediment . Use of the coefficient K at the other cells with calcareous beaches may not be valid, and...originator. Hawaii Regional Sediment Management: Regional Sediment Budget for the Poipu Region of Kauai, HI Edited by Jessica H. Podoski PURPOSE...This Coastal and Hydraulics Engineering Technical Note (CHETN) reviews the development of a regional sediment budget for the Poipu Region on the

  11. Contaminants in surface water and sediments near the Tynagh silver mine site, County Galway, Ireland

    Energy Technology Data Exchange (ETDEWEB)

    O' Neill, A. [School of Planning, Architecture and Civil Engineering, Queen' s University of Belfast, Belfast, Northern Ireland (United Kingdom); Phillips, D.H., E-mail: d.phillips@qub.ac.uk [School of Planning, Architecture and Civil Engineering, Queen' s University of Belfast, Belfast, Northern Ireland (United Kingdom); Bowen, J. [School of Planning, Architecture and Civil Engineering, Queen' s University of Belfast, Belfast, Northern Ireland (United Kingdom); Sen Gupta, B. [School of the Built Environment, Hariot-Watt University, Edinburgh, Scotland (United Kingdom)

    2015-04-15

    A former silver mine in Tynagh, Co. Galway, Ireland is one of the most contaminated mine sites in Europe with maximum concentrations of Zn, As, Pb, Mn, Ni, Cu, and Cd far exceeding guideline values for water and sediment. The aims of this research were to 1) further assess the contamination, particularly metals, in surface water and sediment around the site, and 2) determine if the contamination has increased 10 years after the Environmental Protection Agency Ireland (EPAI) identified off-site contamination. Site pH is alkaline to neutral because CaCO{sub 3}-rich sediment and rock material buffer the exposed acid generating sulphide-rich ore. When this study was compared to the previous EPAI study conducted 10 years earlier, it appeared that further weathering of exposed surface sediment had increased concentrations of As and other potentially toxic elements. Water samples from the tailings ponds and adjacent Barnacullia Stream had concentrations of Al, Cd, Mn, Zn and Pb above guideline values. Lead and Zn concentrations from the tailings pond sediment were 16 and 5 times higher, respectively, than concentrations reported 10 years earlier. Pb and Zn levels in most sediment samples exceeded the Expert Group (EGS) guidelines of 1000 and 5000 mg/kg, respectively. Arsenic concentrations were as high as 6238 mg/kg in the tailings ponds sediment, which is 62 and 862 times greater than the EGS and Canadian Soil Quality Guidelines (CSQG), respectively. Cadmium, Cu, Fe, Mn, Pb and Zn concentrations in water and sediment were above guideline values downstream of the site. Additionally, Fe, Mn and organic matter (OM) were strongly correlated and correlated to Zn, Pb, As, Cd, Cu and Ni in stream sediment. Therefore, the nearby Barnacullia Stream is also a significant pathway for contaminant transport to downstream areas. Further rehabilitation of the site may decrease the contamination around the area. - Highlights: • Tynagh silver mine in Co. Galway, Ireland is a source of

  12. Dating sediment in a fast sedimentation reservoir using 137Cs and 210Pb

    Science.gov (United States)

    Over 10,000 reservoirs have been constructed in agricultural watersheds in the United States since the 1940s to control floods and sediments. Reservoir sedimentation records provide a unique opportunity to retrospectively study the effects of land use changes and climate variations on sediment produ...

  13. Next generation sequencing reveals distinct fecal pollution signatures in aquatic sediments across gradients of anthropogenic influence

    Directory of Open Access Journals (Sweden)

    Gian Marco Luna

    2016-11-01

    Full Text Available Aquatic sediments are the repository of a variety of anthropogenic pollutants, including bacteria of fecal origin, that reach the aquatic environment from a variety of sources. Although fecal bacteria can survive for long periods of time in aquatic sediments, the microbiological quality of sediments is almost entirely neglected when performing quality assessments of aquatic ecosystems. Here we investigated the relative abundance, patterns and diversity of fecal bacterial populations in two coastal areas in the Northern Adriatic Sea (Italy: the Po river prodelta (PRP, an estuarine area receiving significant contaminant discharge from one of the largest European rivers and the Lagoon of Venice (LV, a transitional environment impacted by a multitude of anthropogenic stressors. From both areas, several indicators of fecal and sewage contamination were determined in the sediments using Next Generation Sequencing (NGS of 16S rDNA amplicons. At both areas, fecal contamination was high, with fecal bacteria accounting for up to 3.96% and 1.12% of the sediment bacterial assemblages in PRP and LV, respectively. The magnitude of the fecal signature was highest in the PRP site, highlighting the major role of the Po river in spreading microbial contaminants into the adjacent coastal area. In the LV site, fecal pollution was highest in the urban area, and almost disappeared when moving to the open sea. Our analysis revealed a large number of fecal Operational Taxonomic Units (OTU, 960 and 181 in PRP and LV, respectively and showed a different fecal signature in the two areas, suggesting a diverse contribution of human and non-human sources of contamination. These results highlight the potential of NGS techniques to gain insights into the origin and fate of different fecal bacteria populations in aquatic sediments.

  14. Highlights Eurosites insights; highlights on image, implementation, interpretation and integration of Natura 2000 in European perspective; United Kingdom, Sweden, Spain, France and Hungary

    NARCIS (Netherlands)

    Neven, M.G.G.; Kistenkas, F.H.

    2005-01-01

    Highlighting the main report Eurosites Insights this comparative study analyses Natura 2000 nature conservation (EU Birds- and Habitats Directives) alongside the key issues of image, implementation, interpretation and integration. Having quick scanned the EU25, five member states have been selected

  15. Suspended sediment yield in Texas watersheds

    Science.gov (United States)

    Coonrod, Julia Ellen Allred

    The Texas Water Development Board collected suspended sediment samples across the state of Texas for approximately 60 years. Until this research, no comprehensive analysis of the data had been conducted. This study compiles the suspended sediment data along with corresponding streamflow and rainfall. GIS programs are developed which characterize watersheds corresponding to the sediment gauging stations. The watersheds are characterized according to topography, climate, soils, and land use. All of the data is combined to form several SAS data sets which can subsequently be analyzed using regression. Annual data for all of the stations across the state are classified temporally and spatially to determine trends in the sediment yield. In general, the suspended sediment load increases with increasing runoff but no correlation exists with rainfall. However, the annual average rainfall can be used to classify the watersheds according to climate, which improves the correlation between sediment load and runoff. The watersheds with no dams have higher sediment loads than watersheds with dams. Dams in the drier parts of Texas reduce the sediment load more than dams in the wetter part of the state. Sediment rating curves are developed separately for each basin in Texas. All but one of the curves fall into a band which varies by about two orders of magnitude. The study analyzes daily time series data for the Lavaca River near Edna station. USGS data are used to improve the sediment rating curve by the addition of physically related variables and interaction terms. The model can explain an additional 41% of the variability in sediment concentration compared to a simple bivariate regression of sediment load and flow. The TWDB daily data for the Lavaca River near Edna station are used to quantify temporal trends. There is a high correlation between sediment load and flowrate for the Lavaca River. The correlation can be improved by considering a flow-squared term and by

  16. Accumulation of heavy metals and trace elements in fluvial sediments received effluents from traditional and semiconductor industries.

    Science.gov (United States)

    Hsu, Liang-Ching; Huang, Ching-Yi; Chuang, Yen-Hsun; Chen, Ho-Wen; Chan, Ya-Ting; Teah, Heng Yi; Chen, Tsan-Yao; Chang, Chiung-Fen; Liu, Yu-Ting; Tzou, Yu-Min

    2016-09-29

    Metal accumulation in sediments threatens adjacent ecosystems due to the potential of metal mobilization and the subsequent uptake into food webs. Here, contents of heavy metals (Cd, Cr, Cu, Ni, Pb, and Zn) and trace elements (Ga, In, Mo, and Se) were determined for river waters and bed sediments that received sewage discharged from traditional and semiconductor industries. We used principal component analysis (PCA) to determine the metal distribution in relation to environmental factors such as pH, EC, and organic matter (OM) contents in the river basin. While water PCA categorized discharged metals into three groups that implied potential origins of contamination, sediment PCA only indicated a correlation between metal accumulation and OM contents. Such discrepancy in metal distribution between river water and bed sediment highlighted the significance of physical-chemical properties of sediment, especially OM, in metal retention. Moreover, we used Se XANES as an example to test the species transformation during metal transportation from effluent outlets to bed sediments and found a portion of Se inventory shifted from less soluble elemental Se to the high soluble and toxic selenite and selenate. The consideration of environmental factors is required to develop pollution managements and assess environmental risks for bed sediments.

  17. Sinks and sources: Assessing microplastic abundance in river sediment and deposit feeders in an Austral temperate urban river system.

    Science.gov (United States)

    Nel, Holly A; Dalu, Tatenda; Wasserman, Ryan J

    2018-01-15

    Microplastics are important novel pollutants in freshwaters but their behaviour in river sediments is poorly understood due to the large amounts of coloured dissolved organic matter that impede sample processing. The present study aimed to 1.) estimate the microplastic pollution dynamics in an urban river system experiencing temporal differences in river flow, and 2.) investigate the potential use of chironomids as indicators of microplastic pollution levels in degraded freshwater environments. Microplastic levels were estimated from sediment and Chironomus spp. larvae collected from various sites along the Bloukrans River system, in the Eastern Cape South Africa during the summer and winter season. River flow, water depth, channel width, substrate embeddedness and sediment organic matter were simultaneously collected from each site. The winter season was characterised by elevated microplastic abundances, likely as a result of lower energy and increased sediment deposition associated with reduced river flow. In addition, results showed that particle distribution may be governed by various other external factors, such as substrate type and sediment organic matter. The study further highlighted that deposit feeders associated with the benthic river habitats, namely Chironomus spp. ingest microplastics and that the seasonal differences in sediment microplastic dynamics were reflected in chironomid microplastic abundance. There was a positive, though weakly significant relationship between deposit feeders and sediment suggesting that deposit feeders such as Chironomus spp. larvae could serve as an important indicator of microplastic loads within freshwater ecosystems. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Accumulation of heavy metals and trace elements in fluvial sediments received effluents from traditional and semiconductor industries

    Science.gov (United States)

    Hsu, Liang-Ching; Huang, Ching-Yi; Chuang, Yen-Hsun; Chen, Ho-Wen; Chan, Ya-Ting; Teah, Heng Yi; Chen, Tsan-Yao; Chang, Chiung-Fen; Liu, Yu-Ting; Tzou, Yu-Min

    2016-09-01

    Metal accumulation in sediments threatens adjacent ecosystems due to the potential of metal mobilization and the subsequent uptake into food webs. Here, contents of heavy metals (Cd, Cr, Cu, Ni, Pb, and Zn) and trace elements (Ga, In, Mo, and Se) were determined for river waters and bed sediments that received sewage discharged from traditional and semiconductor industries. We used principal component analysis (PCA) to determine the metal distribution in relation to environmental factors such as pH, EC, and organic matter (OM) contents in the river basin. While water PCA categorized discharged metals into three groups that implied potential origins of contamination, sediment PCA only indicated a correlation between metal accumulation and OM contents. Such discrepancy in metal distribution between river water and bed sediment highlighted the significance of physical-chemical properties of sediment, especially OM, in metal retention. Moreover, we used Se XANES as an example to test the species transformation during metal transportation from effluent outlets to bed sediments and found a portion of Se inventory shifted from less soluble elemental Se to the high soluble and toxic selenite and selenate. The consideration of environmental factors is required to develop pollution managements and assess environmental risks for bed sediments.

  19. An evaluation of temporal changes in sediment accumulation and impacts on carbon burial in Mobile Bay, Alabama, USA

    Science.gov (United States)

    Smith, Christopher G.; Osterman, Lisa E.

    2014-01-01

    The estuarine environment can serve as either a source or sink of carbon relative to the coastal ocean carbon budget. A variety of time-dependent processes such as sedimentation, carbon supply, and productivity dictate how estuarine systems operate, and Mobile Bay is a system that has experienced both natural and anthropogenic perturbations that influenced depositional processes and carbon cycling. Sediments from eight box cores provide a record of change in bulk sediment accumulation and carbon burial over the past 110 years. Accumulation rates in the central part of the basin (0.09 g cm−2) were 60–80 % less than those observed at the head (0.361 g cm−2) and mouth (0.564 g cm−2) of the bay. Sediment accumulation in the central bay decreased during the past 90 years in response to both anthropogenic (causeway construction) and natural (tropical cyclones) perturbations. Sediment accumulation inevitably increased the residence time of organic carbon in the oxic zone, as observed in modeled remineralization rates, and reduced the overall carbon burial. Such observations highlight the critical balance among sediment accumulation, carbon remineralization, and carbon burial in dynamic coastal environments. Time-series analysis based solely on short-term observation would not capture the long-term effects of changes in sedimentation on carbon cycling. Identifying these relationships over longer timescales (multi-annual to decadal) will provide a far better evaluation of coastal ocean carbon budgets.

  20. Variability of in situ sediment strength and pore pressure behavior of tidal estuary surface sediments

    Science.gov (United States)

    Lucking, Greg; Stark, Nina; Lippmann, Thomas; Smyth, Stephen

    2017-10-01

    Tidal estuaries feature spatially and temporally varying sediment dynamics and characteristics. Particularly, the variability of geotechnical sediment parameters is still poorly understood, limiting the prediction of long-term sediment stability and dynamics. This paper presents results from an in situ investigation of surficial sediments (≤50 cm) in a tidal estuary in New Hampshire (USA), using a portable free fall penetrometer. The aim is to investigate variations in sediment strength and pore pressure behavior with regard to sediment type and seabed morphology. The study also provides a detailed analysis of high velocity impact pore pressure data to derive information about sediment type and permeability. The penetrometer was deployed 227 times, and the findings are correlated to 78 sediment samples. Differences in sediment strength and type were found when transitioning from tidal flats to the deeper channels. Finer-grained sediments located predominantly on the tidal flats appeared well consolidated with noticeable and spatially consistent sediment strength (reflected in an estimate of quasi-static bearing capacity qsbcmax 10 kPa). Sediments with higher sand content (>75%) showed more variations in strength relating to differences in gradation, and likely represent loose and poorly consolidated sands (qsbcmax 10-55 kPa). The rate at which the recorded excess pore pressures approached equilibrium after penetration was classified and related to sediment type. The data indicate that the development of excess pore pressures upon impact and during penetration may provide additional insight into the nature and layering of bed material, such as identifying a desiccated or over-consolidated dilative surficial layer. In summary, with varying sediment grain size distributions, bulk densities and morphology, sediment strength and pore pressure behavior can vary significantly within a tidal estuary.

  1. Moving beyond Text Highlights: Inferring Users' Interests to Improve the Relevance of Retrieval

    Science.gov (United States)

    Balakrishnan, Vimala; Mehmood, Yasir; Nagappan, Yoganathan

    2016-01-01

    Introduction: Studies have indicated that users' text highlighting behaviour can be further manipulated to improve the relevance of retrieved results. This article reports on a study that examined users' text highlight frequency, length and users' copy-paste actions. Method: A binary voting mechanism was employed to determine the weights for the…

  2. North-American Conference Highlights the Treatment of Trauma Utilizing Guided Imagery and Music

    DEFF Research Database (Denmark)

    Scott-Montcrieff, Suzannah; Beck, Bolette Daniels; Montgomery, Erin

    2015-01-01

    A report on the 2015 Association for Music and Imagery conference highlights papers that address clinical practice and research using Guided Imagery and Music for the treatment of trauma.......A report on the 2015 Association for Music and Imagery conference highlights papers that address clinical practice and research using Guided Imagery and Music for the treatment of trauma....

  3. Quantifying sediment sources in a lowland agricultural catchment pond using {sup 137}Cs activities and radiogenic {sup 87}Sr/{sup 86}Sr ratios

    Energy Technology Data Exchange (ETDEWEB)

    Le Gall, Marion; Evrard, Olivier [Laboratoire des Sciences et de l' Environnement, UMR 8212 (CEA/CNRS/UVSQ), Université Paris-Saclay, Domaine du CNRS, Avenue de la Terrasse, 91198 Gif-sur-Yvette Cedex (France); Foucher, Anthony [E.A 6293, Laboratoire GéoHydrosystèmes Continentaux (GéHCO), Université F. Rabelais de Tours, Faculté des Sciences et Techniques, Parc de Grandmont, 37200 Tours (France); Laceby, J. Patrick [Laboratoire des Sciences et de l' Environnement, UMR 8212 (CEA/CNRS/UVSQ), Université Paris-Saclay, Domaine du CNRS, Avenue de la Terrasse, 91198 Gif-sur-Yvette Cedex (France); Salvador-Blanes, Sébastien [E.A 6293, Laboratoire GéoHydrosystèmes Continentaux (GéHCO), Université F. Rabelais de Tours, Faculté des Sciences et Techniques, Parc de Grandmont, 37200 Tours (France); Thil, François; Dapoigny, Arnaud; Lefèvre, Irène [Laboratoire des Sciences et de l' Environnement, UMR 8212 (CEA/CNRS/UVSQ), Université Paris-Saclay, Domaine du CNRS, Avenue de la Terrasse, 91198 Gif-sur-Yvette Cedex (France); Cerdan, Olivier [Département Risques et Prévention, Bureau de Recherches Géologiques et Minières, 3 avenue Claude Guillemin, 45060 Orléans (France); and others

    2016-10-01

    the pond. This original sediment fingerprinting study demonstrates the potential of combining radionuclide and strontium isotopic geochemistry measurements to quantify sediment sources in cultivated catchments. - Highlights: • Surface sources supplied the majority of pond and core sediment. • Lithological sources were well mixed in surface pond sediment. • Lithological sources varied through time in the sediment core. • Temporal lithological fluctuations likely resulted from landscape modifications. • Understanding sediment dynamics is important in agricultural drained catchments.

  4. Developing a biomonitoring tool for fine sediment

    Science.gov (United States)

    Turley, Matt; Bilotta, Gary; Brazier, Richard; Extence, Chris

    2014-05-01

    Sediment is an essential component of freshwater ecosystems; however anthropogenic activities can lead to elevated sediment delivery which can impact on the physical, chemical and biological characteristics of these ecosystems. Ultimately, this can result in a loss of ecosystem services worth more than 1.7 trillion per annum. As such it is important that sediment, which is one of the most commonly attributed causes of water quality impairment globally, is managed in order to minimise these impacts. The current EU environmental quality standard for sediment (monitored in the form of suspended solids) is 25 mg L-1 for all environments. It is widely recognised that this standard is unsuitable and not ecologically relevant. Furthermore, it requires a substantial resource investment to monitor sediment in this form as part of national and international water resource legislation. In recognition of this the development of sediment-specific biomonitoring tools is receiving increasing attention. The Proportion of Sediment-Sensitive Invertebrates (PSI) index is one such tool that is designed to indicate levels of fine sediment (

  5. Laboratory theory and methods for sediment analysis

    Science.gov (United States)

    Guy, Harold P.

    1969-01-01

    The diverse character of fluvial sediments makes the choice of laboratory analysis somewhat arbitrary and the pressing of sediment samples difficult. This report presents some theories and methods used by the Water Resources Division for analysis of fluvial sediments to determine the concentration of suspended-sediment samples and the particle-size distribution of both suspended-sediment and bed-material samples. Other analyses related to these determinations may include particle shape, mineral content, and specific gravity, the organic matter and dissolved solids of samples, and the specific weight of soils. The merits and techniques of both the evaporation and filtration methods for concentration analysis are discussed. Methods used for particle-size analysis of suspended-sediment samples may include the sieve pipet, the VA tube-pipet, or the BW tube-VA tube depending on the equipment available, the concentration and approximate size of sediment in the sample, and the settling medium used. The choice of method for most bed-material samples is usually limited to procedures suitable for sand or to some type of visual analysis for large sizes. Several tested forms are presented to help insure a well-ordered system in the laboratory to handle the samples, to help determine the kind of analysis required for each, to conduct the required processes, and to assist in the required computations. Use of the manual should further 'standardize' methods of fluvial sediment analysis among the many laboratories and thereby help to achieve uniformity and precision of the data.

  6. Sedimentation in Brackwasserhäfen

    OpenAIRE

    Nasner, Horst; Pieper, Rainer; Torn, Patrick

    2015-01-01

    Das Heft 150 der Mitteilungsreihe des Instituts für Wasserbau und Wasserwirtschaft der TU Darmstadt behandelt das Thema "Sedimentation in Brackwasserhäfen". Insbesondere spielt dabei das Mobilitätscerhalten feinkörniger und zum Teil auch kohäsiver Sedimente eine zentrale Rolle.

  7. Experiments on sediment pulses in mountain rivers

    Science.gov (United States)

    Y. Cui; T. E. Lisle; J. E. Pizzuto; G. Parker

    1998-01-01

    Pulses of sediment can be introduced into mountain rivers from such mechanisms as debris flows, landslides and fans at tributary confluences. These processes can be natural or associated with the activities of humans, as in the case of a pulse created by sediment derived from timber harvest or the removal of a dam. How does the river digest these pulses?

  8. Distribution of calcareous nannoplankton in surface sediments ...

    African Journals Online (AJOL)

    Distribution of calcareous nannoplankton in surface sediments along the northern KwaZulu-Natal Bight, South Africa. ... African Journal of Marine Science ... The coccolith assemblages from seafloor sediments over the inner shelf in the northern region of the KwaZulu- Natal Bight on the east coast of South Africa were ...

  9. Bioavailability of Metals in Contaminated Sediments

    Directory of Open Access Journals (Sweden)

    Paller M. H.

    2013-04-01

    Full Text Available Bioavailability controls the transfer of metals from sediments to ecological receptors and humans. It can rarely be predicted from total metal concentrations because it is affected by metal geochemistry in sediments as well as the biochemistry, physiology, and behavior of benthic organisms. There is no single approach for including bioavailability in risk assessments because of variability in site specific conditions and the difficulty of validating methods. Acid-volatile sulfide and simultaneously extracted metals are useful in predicting bioavailability in anoxic sediments containing sulfides that react to form insoluble metal complexes. This method can be improved by adjusting for organic carbon and other ligands that also bind free metals. Site-specific desorption Kd values calculated by sequential extraction methods can be useful in predicting bioavailable metal fractions in oxic and anoxic sediments. A modified desorption distribution coefficient (Kdg can be calculated by extraction with the digestive gut fluids of sediment feeding organisms to account for the effects of ingestion on metal release from sediments. Recently developed in situ measurement technologies can accumulate dissolved metals in a controlled fashion that may correspond with bioavailable metal fractions in sediment. Successful evaluation of bioavailability requires the selection of methods suitable for the organisms and sediment environments under consideration. A weight-of-evidence approach that incorporates multiple lines of evidence can help address uncertainties and increase the likelihood of incorporating bioavailability into remedial decisions.

  10. Suspended sediment concentration and particle size distribution ...

    Indian Academy of Sciences (India)

    face area, shape, minerals and source) and conse- quent interaction with heavy metal concentrations. (HMCs). Recent studies have shown a growing awareness of the wider environmental significance of the suspended sediment loads transported by rivers and streams. This includes the importance of fine grain sediment in ...

  11. Vegetation and sedimentation on coastal foredunes

    NARCIS (Netherlands)

    Keijsers, J.G.S.; Groot, de A.V.; Riksen, M.J.P.M.

    2015-01-01

    On a timescale of years to decades, vegetated foredunes may show various modes of morphological development. Vegetation is one of the factors that determine the sedimentation pattern and thus morphology on the foredune. In turn, the vegetation pattern may be controlled by the sedimentation pattern.

  12. Estimation of suspended sediment concentration by acoustic ...

    African Journals Online (AJOL)

    However, the acoustic properties of natural sediments vary and depend on many parameters such as particle size, shape, mineralogy and distribution of those parameters in sample. Therefore, this study was conducted to determine the possibility of soil sediment concentration with the f and equations, which were obtained ...

  13. Luminescence dating of storm-surge sediment

    NARCIS (Netherlands)

    Cunningham, A.C.

    2011-01-01

    Geological evidence of storm surges has the potential to provide vital information on storm-surge risk. Sediment from the coastal dunes of the Netherlands contains evidence of extreme floods that occurred before reliable measurements of water level began. For these sediments to be useful in

  14. Investigation of relationship between sediment characteristics and ...

    African Journals Online (AJOL)

    The presence and concentration of heavy metals in water bodies may be influenced by human activities. Sediments are the final sink of heavy metals in the water body. This study examined the concentration of heavy metals in the sediments across the outlet of the Forcados. This was intended to examine the relationship ...

  15. GEOCHEMICAL ASSESSMENT OF SEDIMENT IN CAPE TOWN ...

    African Journals Online (AJOL)

    Preferred Customer

    Sample preparation and XRPD analysis. The XRPD instrument was used to determine the solid/mineral phases of the sediments. 1 g (±. 0.0001 g) of the surface sediment sample was weighed. This sample was ground to powder using mortar and pestle. Each powdered sample was sieved through a 40 µm mesh in order to.

  16. Climate variations, soil conservation and reservoir sedimentation

    Science.gov (United States)

    The integrated effects of soil conservation and a wetter climate on reservoir sedimentation were investigated for the Fort Cobb Reservoir watershed in west-central Oklahoma. A 12% wetter climate since the mid-1980s led to an increase in soil erosion and downstream sediment yield that offset the redu...

  17. Trends in the occurrence of human and veterinary antibiotics in the sediments of the Yellow River, Hai River and Liao River in northern China

    Energy Technology Data Exchange (ETDEWEB)

    Zhou Lijun [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Ying Guangguo, E-mail: guang-guo.ying@gig.ac.cn [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Zhao Jianliang [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Yang Jifeng [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Chemistry and Chemical Engineering Department, Hunan University of Arts and Science, Changde 415000 (China); Wang Li; Yang Bin; Liu Shan [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China)

    2011-07-15

    The occurrence of four classes of 17 commonly used antibiotics (including fluoroquinolones, tetracycline, sulfonamides, and macrolides) was investigated in the sediments of the Yellow River, Hai River and Liao River in northern China by using rapid resolution liquid chromatography-tandem mass spectrometry. Higher concentrations were detected for most antibiotics in the sediments of the Hai River than in the sediments of the other rivers. Norfloxacin, ofloxacin, ciprofloxacin and oxytetracycline in the three rivers were most frequently detected with concentrations up to 5770, 1290, 653 and 652 ng/g, respectively. High frequencies and concentrations of the detected antibiotics were often found in the downstream of large cities and areas influenced by feedlot and fish ponds. Good fitted linear regression equations between antibiotic concentration and sediment physicochemical properties (TOC, texture and pH) were also found, indicating that sediment properties are important factors influencing the distribution of antibiotics in the sediment of rivers. - Highlights: > Presence of four classes of commonly used antibiotics in the river sediments. > Higher concentrations in the Hai River than in the Liao River and Yellow River. > Norfloxacin, ofloxacin, ciprofloxacin and oxytetracycline most frequently detected. > High antibiotic concentrations often found in the downstream of large cities. > River sediments are an important reservoir of antibiotics. - Higher concentrations of selected antibiotics were determined in the sediments of the Hai River than in the Liao River and Yellow River.

  18. Design of a marine sediment trap and accessories

    Digital Repository Service at National Institute of Oceanography (India)

    Janakiraman, G.; Fernando, V.; Venkatesan, R.; Rajaraman, V.S.

    The marine sediment trap and the mooring accessories were developed indigenously and were used successfully for the collection of settling sediments in the Arabian Sea The experience gained in using sediment trap and further improvements...

  19. Erythrocyte Sedimentation Rate (ESR): MedlinePlus Lab Test Information

    Science.gov (United States)

    ... this page: https://medlineplus.gov/labtests/erythrocytesedimentationrateesr.html Erythrocyte Sedimentation Rate (ESR) To use the sharing features ... this page, please enable JavaScript. What is an Erythrocyte Sedimentation Rate (ESR)? An erythrocyte sedimentation rate (ESR) ...

  20. Characterization of organic matter in surface sediments of the Mackenzie River Basin, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Carrie, Jesse; Stern, Gary [Department of Environment and Geography, University of Manitoba, Winnipeg, MB (Canada)]|[Freshwater Institute, Department of Fisheries and Oceans, 501 University Crescent, Winnipeg, MB (Canada); Sanei, Hamed; Goodarzi, Fariborz [Geological Survey of Canada-Calgary, 3303 33rd St. NW, Calgary, AB (Canada); Wang, Feiyue [Department of Environment and Geography, University of Manitoba, Winnipeg, MB (Canada)]|[Department of Chemistry, University of Manitoba, Winnipeg, MB (Canada)

    2009-01-31

    The particulate organic matter in < 63 {mu}m surface sediments from the Mackenzie River and its main tributaries was studied using Rock-Eval pyrolysis and organic petrology. The organic matter in the sediments is dominated by refractory residual organic carbon (RC) of mainly terrigenous nature, as indicated by abundant inertinite, vitrinite, and type III kerogen. Sediments from the tributaries contained significantly more algal-derived organic matter than from the main channel of the river, highlighting the importance of low-energy system dynamics in the tributaries, which allows modest algal production, more accumulation, and better preservation of autochthonous organic matter. This is particularly true for tributaries fed by lacustrine systems, which showed the highest S1 and S2 fractions, and consequently higher total particulate organic carbon (POC) in the basin. Organic petrology of the sediment samples confirms abundant liptinitic materials (i.e., fat-rich structured algae, spores and pollen, cuticles, and resins). Forest fire and coal deposits are also confirmed to contribute to the basin. Assuming that suspended and fine surfacial sediments have a similar OC composition, the Mackenzie River is estimated to deliver a total POC flux of 1.1 Mt C/yr to its delta, of which 85% is residual carbon with liptinitic OC (S1 + S2) and S3 accounting for another 9% and 6%, respectively. (author)

  1. Analysis of Antarctic glacigenic sediment provenance through geochemical and petrologic applications

    Science.gov (United States)

    Licht, Kathy J.; Hemming, Sidney R.

    2017-05-01

    The number of provenance studies of glacigenic sediments in Antarctica has increased dramatically over the past decade, providing an enhanced understanding of ice sheet history and dynamics, along with the broader geologic history. Such data have been used to assess glacial erosion patterns at the catchment scale, flow path reconstructions over a wide range of scales, and ice sheet fluctuations indicated by iceberg rafted debris in circumantarctic glacial marine sediments. It is notable that even though most of the bedrock of the continent is ice covered and inaccessible, provenance data can provide such valuable information about Antarctic ice and can even be used to infer buried rock types along with their geo- and thermochronologic history. Glacigenic sediments provide a broader array of provenance analysis opportunities than any other sediment type because of their wide range of grain sizes, and in this paper we review methods and examples from all size fractions that have been applied to the Antarctic glacigenic sedimentary record. Interpretations of these records must take careful consideration of the choice of analytical methods, uneven patterns of erosion, and spatial variability in sediment transport and rock types, which all may lead to a preferential identification of different elements of sources in the provenance analyses. Because of this, we advocate a multi-proxy approach and highlight studies that demonstrate the value of selecting complementary provenance methods.

  2. Nano-TiO2 affects Cu speciation, extracellular enzyme activity, and bacterial communities in sediments.

    Science.gov (United States)

    Fan, Wenhong; Liu, Tong; Li, Xiaomin; Peng, Ruishuang; Zhang, Yilin

    2016-11-01

    In aquatic ecosystems, titanium dioxide nanoparticles (nano-TiO2) coexist with heavy metals and influence the existing forms and toxicities of the metal in water. However, limited information is available regarding the ecological risk of this coexistence in sediments. In this study, the effect of nano-TiO2 on Cu speciation in sediments was investigated using sequential extraction. The microcosm approach was also employed to analyze the effects of the coexistence of nano-TiO2 and Cu on extracellular enzyme activity and bacterial communities in sediments. Results showed that nano-TiO2 decreased the organic matter-bound fraction of Cu and increased the corresponding residual fraction Cu. As a result, speciation of exogenous Cu in sediments changed. During the course of the 30-day experiment, the presence of nano-TiO2 did not affect Cu-induced changes in bacterial community structure. However, the coexistence of nano-TiO2 and Cu restrained the activity of bacterial extracellular enzymes, such as alkaline phosphatase and β-glucosidase. The degree of inhibition also varied because of the different properties of extracellular enzymes. This research highlighted the importance of understanding and predicting the effects of the coexistence of nanomaterials and other pollutants in sediments. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Feedbacks between bivalve density, flow, and suspended sediment concentration on patch stable states.

    Science.gov (United States)

    Coco, Giovanni; Thrush, Simon F; Green, Malcolm O; Hewitt, Judi E

    2006-11-01

    We explore the role of biophysical feedbacks occurring at the patch scale (spatial scale of tens of meters) that influence bivalve physiological condition and affect patch stability by developing a numerical model for the pinnid bivalve, Atrina zelandica, in cohesive sediments. Simulated feedbacks involve bivalve density, flow conditions (assumed to be primarily influenced by local water depth and peak current speed), suspended sediment concentration (evaluated through a balance between background concentration, deposition, and erosion), and changes in the physiology of Atrina derived from empirical study. The model demonstrates that high bivalve density can lead to skimming flow and to a concomitant decrease in resuspension that will affect suspended sediment concentration over the patch directly feeding back on bivalve physiology. Consequently, for a given flow and background suspended sediment load, the stability of a patch directly depends on the size and density of bivalves in the patch. Although under a range of conditions patch stability is ensured independently of bivalve density, simulations clearly indicate that sudden changes in bivalve density or suspended sediment concentration can substantially affect patch structure and lead to different stable states. The model highlights the role of interactions between organisms, flow, and broader scale environmental conditions in providing a mechanistic explanation for the patchy occurrence of benthic suspension feeders.

  4. Multi-scale factors affecting composition, diversity, and abundance of sediment denitrifying microorganisms in Yangtze lakes.

    Science.gov (United States)

    Jiang, Xiaoliang; Yao, Lu; Guo, Laodong; Liu, Guihua; Liu, Wenzhi

    2017-11-01

    Sediment denitrification is the dominant nitrogen removal pathway in many aquatic habitats and can be regulated by local-, landscape-, and regional-scale factors. However, the mechanisms for how these multiple scale factors and their interactions affect the sediment denitrifying communities remain poorly understood. In this study, we investigated the community composition, diversity, and abundance of nitrite reductase genes (nirK and nirS)-encoding denitrifiers in 74 sediment samples from 22 Yangtze lakes using clone library and quantitative PCR techniques. Information of location, climate, catchment land use, water quality, sediment properties, and plant communities at each sampling site was analyzed to elucidate the effects of regional, landscape, and local factors on the characteristics of sediment denitrifying communities. Results of canonical correspondence analysis indicated that local factors were the key determinants of denitrifying community composition, accounting for over 20% of the total variation. Additionally, certain regional and landscape factors, including elevation and catchment built-up land, were also significantly related to the composition of denitrifying communities. Variance partitioning analyses revealed that diversity and abundance in the nirK denitrifier community were largely influenced by local factors, while those in the nirS community were controlled by both local and regional factors. Our findings highlight the importance of using different scale factors to explain adequately the composition and structure of denitrifying communities in aquatic environments.

  5. Analysis of Sedimentation in Wonogiri Reservoir

    Directory of Open Access Journals (Sweden)

    Tri Joko Inti Budi Santosa

    2016-01-01

    Full Text Available The Wonogiri reservoir which has 730 million cubic meters of total storage, 90 square kilometers of water area, and 1260 square kilometers of catchment area, is located in the Wonogiri Regency, Central Java Province. It was first established in 1981 and began its operation in 1982 with the expectation that it would last for about 100 years. Today (2002 the reservoir has got a serious problem of sedimentation. The sedimentation is so large that it would decrease the capacity storage of the reservoir and would shorten the length of operation. Therefore, it is necessary to predict the sediment that comes into the reservoir. This research would be based on the total sediment calculation of the sedimentation, through some methods, such as echo sounding measured data, land erosion (USLE, the calculation of the sediment in rivers. This research calculates the sediment capacities based on the water flow data and the sediment rating curves in rivers of Keduang, Tirtomoyo, Temon, upstream reach of Bengawan Solo, Alang, and Wuryantoro. The suspended load was calculated based on the sediment rating curves, whereas the bed load was computed as the percentage of the suspended load. The sum of both calculation results would be the total sediment. The calculation result showed that the total sediment which has come into the reservoir is 6.68 million cubic meters per year. As a comparison, the writer noted that the former researcher using echo sounding method done by the Faculty of Geography of the Universitas Gadjah Mada in 1985, it found that the total sediment capacity which came into the reservoir was 6.60 million cubic meters per year or 5.40 mm per year of sheet erosion. The other research using echo sounding method done by JICA in 2000 found that the total sediment which had come into the reservoir was 4.50 million cubic meters per year or 3.50 mm per year of sheet erosion. By knowing the results of calculation of the total sediment, we can learn that

  6. Geochemistry of sediments in cores and sediment traps from Bear Lake, Utah and Idaho

    Science.gov (United States)

    Bischoff, James L.; Cummins, Kathleen; Shamp, Donald D.

    2005-01-01

    The present study of Bear Lake began in 1998. Initially, the study utilized sediments from three long cores (up to 5 m) previously collected in 1996 and short cores (up to 40 cm) collected in 1998. The short cores were specifically acquired to preserve the uppermost layers of sediment that may have been lost in the long cores. In addition, three arrays of sediment traps were deployed during the summer of 1998, and sediment from these traps was collected during the summers of 1999 and 2000 (see Dean and others, 2005, for core and sediment trap locations). The cores and sediment traps were sampled, and splits were distributed to various investigators for analyses of a wide variety of sediment parameters. The chemical composition of the acid-soluble component of the sediments is presented in this report. HCl or HNO3 treatment of the sediment quantitatively dissolves the authigenic component of the sediment, a component that includes carbonates, sulfates, and iron-mono sulfides. In the case of Bear Lake, CaCO3 is the major component of the sediment today and for most of the Holocene (Dean and others 2005). The chemical composition of the acid-soluble fraction gives important information on this component and, therefore, insight into the chemical conditions of the lake at the time of carbonate deposition.

  7. Water-sediment flow models for river reaches sediment related pollution control.

    Science.gov (United States)

    Sil, Briti Sundar; Choudhury, Parthasarathi

    2012-07-01

    Hybrid water-sediment flow models for river reaches have been for predicting sediment and sediment related pollutions in water courses. The models are developed by combining sediment rating model and the Muskingum model applicable for a reach. The models incorporate sediment concentration and water discharge variables for a river reach; allow defining downstream sediment rating curve in terms of upstream water discharges. The model is useful in generating sediment concentration graph for a station having no water discharge records. The hybrid models provide forecasting forms that can be used to forecast downstream sediment concentration/water discharges 2kx time unit ahead. The forecasting models are useful for applications in real time namely, in the real time management of sediment related pollution in water courses and in issuing flood warning. Integration of sediment rating model and the Muskingum model increases model parameters and nonlinearity requiring efficient estimation technique for parameter identification. To identify parameters in the hybrid models genetic algorithm (GA) based optimization technique can be used. The new model relies on the Muskingum model, obey continuity requirement and the parameters can be used in the Muskingum model with water discharges to estimate/predict downstream water discharge values. The proposed model formulations are demonstrated for simulating and forecasting sediment concentration and water discharges in the Mississippi River Basin, USA. Model parameters are estimated using non-dominated sorting Genetic Algorithm II (NSGA-II). Model results show satisfactory model performances.

  8. Algal bloom sedimentation induces variable control of lake eutrophication by phosphorus inactivating agents

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Changhui [State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008 (China); Bai, Leilei [State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008 (China); Graduate University of Chinese Academy of Sciences (China); Jiang, He-Long, E-mail: hljiang@niglas.ac.cn [State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008 (China); Xu, Huacheng [State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008 (China)

    2016-07-01

    Lake eutrophication typically occurs with a syndrome of algae breeding and biomass accumulation (e.g., algal blooms). Therefore, the effect of algal bloom sedimentation on eutrophication control by phosphorus (P) inactivating agents was assessed herein. Three commercial products, including aluminum (Al) sulfate, iron (Fe) sulfate, and a lanthanum-modified clay (Phoslock®), as well as one easily available by-product, drinking water treatment residue (DWTR), were selected. The most important finding was that during algae sedimentation, P immobilization from the overlying water by Al, Phoslock®, and DWTR was dominated by a long-term slow phase (> 150 d), while Fe has limited effectiveness on the immobilization. Further analysis indicated that the algae sedimentation effect was mainly due to the slow release of P from algae, leading to relatively limited P available for the inactivating agents. Then, a more unfavorable effect on the P immobilization capability of inactivating agents was caused by the induced anaerobic conditions, the released organic matter from algae, and the increased sulfide in the overlying water and sediments during sedimentation. Overall, algae sedimentation induced variable control of eutrophication by P inactivating agents. Accordingly, recommendations for future works about algal lake restoration were also proposed. - Highlights: • A long-term P immobilization by Phoslock®, DWTR, and Al was observed. • Fe had limited effectiveness on P pollution control for overlying water. • Al and Fe enhanced sulfur reduction, while DWTR and Phoslock® had minor effect. • The sedimentation reduced Al and La release from agents, but enhanced Fe release. • The agents changed organic matter compositions and structures in water columns.

  9. Development of autochthonous microbial consortia for enhanced phytoremediation of salt-marsh sediments contaminated with cadmium

    Energy Technology Data Exchange (ETDEWEB)

    Teixeira, Catarina [Centro Interdisciplinar de Investigação Marinha e Ambiental (CIIMAR/CIMAR), Universidade do Porto, Rua dos Bragas, 289, 4050-123 Porto (Portugal); Laboratório de Hidrobiologia e Ecologia, Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313 Porto (Portugal); Almeida, C. Marisa R.; Nunes da Silva, Marta [Centro Interdisciplinar de Investigação Marinha e Ambiental (CIIMAR/CIMAR), Universidade do Porto, Rua dos Bragas, 289, 4050-123 Porto (Portugal); Bordalo, Adriano A. [Centro Interdisciplinar de Investigação Marinha e Ambiental (CIIMAR/CIMAR), Universidade do Porto, Rua dos Bragas, 289, 4050-123 Porto (Portugal); Laboratório de Hidrobiologia e Ecologia, Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313 Porto (Portugal); Mucha, Ana P., E-mail: amucha@ciimar.up.pt [Centro Interdisciplinar de Investigação Marinha e Ambiental (CIIMAR/CIMAR), Universidade do Porto, Rua dos Bragas, 289, 4050-123 Porto (Portugal)

    2014-09-15

    Microbial assisted phytoremediation is a promising, though yet poorly explored, new remediation technique. The aim of this study was to develop autochthonous microbial consortia resistant to cadmium that could enhance phytoremediation of salt-marsh sediments contaminated with this metal. The microbial consortia were selectively enriched from rhizosediments colonized by Juncus maritimus and Phragmites australis. The obtained consortia presented similar microbial abundance but a fairly different community structure, showing that the microbial community was a function of the sediment from which the consortia were enriched. The effect of the bioaugmentation with the developed consortia on cadmium uptake, and the microbial community structure associated to the different sediments were assessed using a microcosm experiment. Our results showed that the addition of the cadmium resistant microbial consortia increased J. maritimus metal phytostabilization capacity. On the other hand, in P. australis, microbial consortia amendment promoted metal phytoextraction. The addition of the consortia did not alter the bacterial structure present in the sediments at the end of the experiments. This study provides new evidences that the development of autochthonous microbial consortia for enhanced phytoremediation of salt-marsh sediments contaminated with cadmium might be a simple, efficient, and environmental friendly remediation procedure. Capsule abstract: Development of autochthonous microbial consortia resistant to cadmium that enhanced phytoremediation by salt-marsh plants, without a long term effect on sediment bacterial diversity. - Highlights: • Cd resistant microbial consortia were developed and applied to salt-marsh sediments. • In Phragmites australis the consortia amendment promoted metal phytoextraction. • The consortia addition increased Juncus maritimus phytostabilization capacity. • No long term changes on the rhizosediment bacterial structure were observed.

  10. Dynamic linear models to explore time-varying suspended sediment-discharge rating curves

    Science.gov (United States)

    Ahn, Kuk-Hyun; Yellen, Brian; Steinschneider, Scott

    2017-06-01

    This study presents a new method to examine long-term dynamics in sediment yield using time-varying sediment-discharge rating curves. Dynamic linear models (DLMs) are introduced as a time series filter that can assess how the relationship between streamflow and sediment concentration or load changes over time in response to a wide variety of natural and anthropogenic watershed disturbances or long-term changes. The filter operates by updating parameter values using a recursive Bayesian design that responds to 1 day-ahead forecast errors while also accounting for observational noise. The estimated time series of rating curve parameters can then be used to diagnose multiscale (daily-decadal) variability in sediment yield after accounting for fluctuations in streamflow. The technique is applied in a case study examining changes in turbidity load, a proxy for sediment load, in the Esopus Creek watershed, part of the New York City drinking water supply system. The results show that turbidity load exhibits a complex array of variability across time scales. The DLM highlights flood event-driven positive hysteresis, where turbidity load remained elevated for months after large flood events, as a major component of dynamic behavior in the rating curve relationship. The DLM also produces more accurate 1 day-ahead loading forecasts compared to other static and time-varying rating curve methods. The results suggest that DLMs provide a useful tool for diagnosing changes in sediment-discharge relationships over time and may help identify variability in sediment concentrations and loads that can be used to inform dynamic water quality management.

  11. Effects of oil sands sediments on fish

    Energy Technology Data Exchange (ETDEWEB)

    Parrott, J.; Colavecchia, M.; Hewitt, L.; Sherry, J.; Headley, J. [Environment Canada, Ottawa, ON (Canada); Turcotte, D.; Liber, K. [Saskatchewan Univ., Regina, SK (Canada)

    2010-07-01

    This paper described a collaborative project organized by Natural Resources Canada (NRCan) Panel of Energy Research and Development (PERD) with researchers from Environment Canada and the University of Saskatchewan. The 4-year study was conducted to assess the toxicity of oil sands sediments and river waters, and reclamation ponds and sediments on laboratory-raised fish. Three sediments from rivers were evaluated for their potential to cause adverse impacts on fathead minnow eggs and larvae for a period of 18 days. The study monitored hatching, larval survival, development, and growth. Naphthenic acids (NA), polycyclic aromatic hydrocarbons (PAHs) and metals were measured in the sediments to determine if the compounds can be correlated with observed toxicity. The study will also assess walleye eggs exposed to sediments, and in situ fish exposures. Toxicity identification and evaluation (TIE) studies will be conducted to isolate the fractions that may affect fish development and growth.

  12. Uncertainty in tsunami sediment transport modeling

    Science.gov (United States)

    Jaffe, Bruce E.; Goto, Kazuhisa; Sugawara, Daisuke; Gelfenbaum, Guy R.; La Selle, SeanPaul M.

    2016-01-01

    Erosion and deposition from tsunamis record information about tsunami hydrodynamics and size that can be interpreted to improve tsunami hazard assessment. We explore sources and methods for quantifying uncertainty in tsunami sediment transport modeling. Uncertainty varies with tsunami, study site, available input data, sediment grain size, and model. Although uncertainty has the potential to be large, published case studies indicate that both forward and inverse tsunami sediment transport models perform well enough to be useful for deciphering tsunami characteristics, including size, from deposits. New techniques for quantifying uncertainty, such as Ensemble Kalman Filtering inversion, and more rigorous reporting of uncertainties will advance the science of tsunami sediment transport modeling. Uncertainty may be decreased with additional laboratory studies that increase our understanding of the semi-empirical parameters and physics of tsunami sediment transport, standardized benchmark tests to assess model performance, and development of hybrid modeling approaches to exploit the strengths of forward and inverse models.

  13. Assessing the potential toxicity of resuspended sediment

    Energy Technology Data Exchange (ETDEWEB)

    Bonnet, C.; Babut, M.; Ferard, J.F.; Martel, L.; Garric, J.

    2000-05-01

    Two moderately contaminated freshwater sediments (Sorel Harbour, St. Lawrence River, Canada) were subjected to a suspension event. The objective was to assess the environmental impact of the disposal of dredged material in water, in particular, the short-term effects of dumping on the water column and the long-term effects of dredged sediment deposits. In a series of microcosms, the sediments were left to stand for 25 d under flow-through conditions. In a second series of microcosms, sediments were vigorously suspended for 15 min before being left to settle and were submitted to the same treatment as reference sediments during the following 25 d. Physicochemical and biological parameters (Daphnia magna and Hydra attenuata survival) were measured in overlying water throughout the experiment. Sediment toxicity was assessed with Chironomus tentans and Hyalella azteca exposed to sediments collected at both the beginning and end of the 25-d period. Pore-water toxicity was evaluated with D. magna. During the suspension process, in the Sorel Harbour mixed sediment overlying water, the authors observed effects on H. attenuata survival and ammonia and metals (chromium, copper, and zinc) releases. Meanwhile, in reference (nonmixed) and mixed sediments as well as in associated pore waters, there were no significant chemical modifications no biological effects after the 25-d experiments. The developed approach, which attempts to simulate a dumping process, aims at allowing the assessment of the short- and long-term hazards resulting from a resuspension process in overlying water and in resettled sediments using both chemical and biological measurements.

  14. Fluctuations and Instability in Sedimentation

    KAUST Repository

    Guazzelli, Élisabeth

    2011-01-21

    This review concentrates on the fluctuations of the velocities of sedimenting spheres, and on the structural instability of a suspension of settling fibers. For many years, theoretical estimates and numerical simulations predicted the fluctuations of the velocities of spheres to increase with the size of the container, whereas experiments found no such variation. Two ideas have increased our understanding. First, the correlation length of the velocity fluctuations was found experimentally to be 20 interparticle separations. Second, in dilute suspensions, a vertical variation in the concentration due to the spreading of the front with the clear fluid can inhibit the velocity fluctuations. In a very dilute regime, a homogeneous suspension of fibers suffers a spontaneous instability in which fast descending fiber-rich columns are separated by rising fiber-sparse columns. In a semidilute regime, the settling is hindered, more so than for spheres. © 2011 by Annual Reviews. All rights reserved.

  15. Relationship of Bacterial Richness to Organic Degradation Rate and Sediment Age in Subseafloor Sediment.

    Science.gov (United States)

    Walsh, Emily A; Kirkpatrick, John B; Pockalny, Robert; Sauvage, Justine; Spivack, Arthur J; Murray, Richard W; Sogin, Mitchell L; D'Hondt, Steven

    2016-08-15

    Subseafloor sediment hosts a large, taxonomically rich, and metabolically diverse microbial ecosystem. However, the factors that control microbial diversity in subseafloor sediment have rarely been explored. Here, we show that bacterial richness varies with organic degradation rate and sediment age. At three open-ocean sites (in the Bering Sea and equatorial Pacific) and one continental margin site (Indian Ocean), richness decreases exponentially with increasing sediment depth. The rate of decrease in richness with increasing depth varies from site to site. The vertical succession of predominant terminal electron acceptors correlates with abundance-weighted community composition but does not drive the vertical decrease in richness. Vertical patterns of richness at the open-ocean sites closely match organic degradation rates; both properties are highest near the seafloor and decline together as sediment depth increases. This relationship suggests that (i) total catabolic activity and/or electron donor diversity exerts a primary influence on bacterial richness in marine sediment and (ii) many bacterial taxa that are poorly adapted for subseafloor sedimentary conditions are degraded in the geologically young sediment, where respiration rates are high. Richness consistently takes a few hundred thousand years to decline from near-seafloor values to much lower values in deep anoxic subseafloor sediment, regardless of sedimentation rate, predominant terminal electron acceptor, or oceanographic context. Subseafloor sediment provides a wonderful opportunity to investigate the drivers of microbial diversity in communities that may have been isolated for millions of years. Our paper shows the impact of in situ conditions on bacterial community structure in subseafloor sediment. Specifically, it shows that bacterial richness in subseafloor sediment declines exponentially with sediment age, and in parallel with organic-fueled oxidation rate. This result suggests that

  16. Importance of measuring discharge and sediment transport in lesser tributaries when closing sediment budgets

    Science.gov (United States)

    Griffiths, Ronald E.; Topping, David J.

    2017-11-01

    Sediment budgets are an important tool for understanding how riverine ecosystems respond to perturbations. Changes in the quantity and grain size distribution of sediment within river systems affect the channel morphology and related habitat resources. It is therefore important for resource managers to know if a river reach is in a state of sediment accumulation, deficit or stasis. Many sediment-budget studies have estimated the sediment loads of ungaged tributaries using regional sediment-yield equations or other similar techniques. While these approaches may be valid in regions where rainfall and geology are uniform over large areas, use of sediment-yield equations may lead to poor estimations of loads in regions where rainfall events, contributing geology, and vegetation have large spatial and/or temporal variability. Previous estimates of the combined mean-annual sediment load of all ungaged tributaries to the Colorado River downstream from Glen Canyon Dam vary by over a factor of three; this range in estimated sediment loads has resulted in different researchers reaching opposite conclusions on the sign (accumulation or deficit) of the sediment budget for particular reaches of the Colorado River. To better evaluate the supply of fine sediment (sand, silt, and clay) from these tributaries to the Colorado River, eight gages were established on previously ungaged tributaries in Glen, Marble, and Grand canyons. Results from this sediment-monitoring network show that previous estimates of the annual sediment loads of these tributaries were too high and that the sediment budget for the Colorado River below Glen Canyon Dam is more negative than previously calculated by most researchers. As a result of locally intense rainfall events with footprints smaller than the receiving basin, floods from a single tributary in semi-arid regions can have large (≥ 10 ×) differences in sediment concentrations between equal magnitude flows. Because sediment loads do not

  17. Sediments study of lake Martignano

    Energy Technology Data Exchange (ETDEWEB)

    Calace, N.; Marino, S.; Petronio, B.M. [Rome Univ. La Sapienza, Rome (Italy). Dept. of Chemistry; Pietroletti, M.; Tartari, G. [Water Research Institute, National Research Council, Brugherio, MI (Italy)

    2000-10-01

    The aim of this research is to determine heavy metal concentration and their different chemical species in sediments of Lake Martignano, in different periods of the year and in the different sediment layers. Initially were considered twelve stations situated along a transept, then the experimentation was carried out on three stations located at different depths. It's possible to observe a trend, particularly for manganese, to accumulate in the deeper zone of the lake. Most of the elements are present as stable species indicating that the lake Martignano is an unpolluted environment; manganese is present overall in mobile form. This high level of mobile manganese depends on redox potential conditions, so MnO{sub 2} can be reduced and solubilized. Noticeable seasonal variations are not observed, except for manganese in central zone of the lake. The variations observed for manganese can be attributable to an imperfect correspondence of sampling point rather than a seasonal phenomenon. [Italian] Scopo della ricerca e' stato quello di determinare la concentrazione totale e le forme chimiche di alcuni metalli pesanti nei sedimenti del lago di Martignano, prendendo in considerazione piu' strati di sedimento ed effettuando i campionamenti in diversi periodi dell'anno. Inizialmente sono state prese in esame dodici stazioni poste lungo un transetto, in seguito la sperimentazione e' proseguita su tre stazioni. Si e' osservato un accumulo di metalli, in particolare manganese, nella zona centrale del lago. Gran parte dei metalli sono presenti in forme stabili, mentre il manganese si trova in forma mobile. Gli elevati livelli di manganese in forma mobile sono da attribuirsi alle condizioni redox del sistema. Non si sono osservate variazioni stagionali; fa eccezione il manganese nella zona centrale del lago ma le differenze osservate possono essere attribuite alla non omogeneita' del sedimento.

  18. Hanford contaminated sediment stabilization studies

    Energy Technology Data Exchange (ETDEWEB)

    Bruns, L.E.; Key, K.T.; Higley, B.A.

    1977-03-01

    The major problems with radionuclide waste sites in the 200 Area plateau on the Hanford Reservation is the high degree of toxicity or Hazard Index (HI). Transport Factors (TF) are fortunately low but can increase with time and certainly with episodic events such as explosions or earthquakes. Two major tests involving surface affixation were sponsored by the Atlantic Richfield Hanford Company, one by Dowell using M-166 and the other by Battelle-Northwest comparing many different surface affixants. The latex emulsion, M-166, appeared to be well suited for the Hanford desert type area. Of the many surface affixants tested by Battelle-Northwest, Coherex and Aerospray appeared to be the best. As an emergency precaution, 200 barrels of M-166 were purchased for surface affixation in case of a range fire. The subsurface affixants laboratory and field tests include organic polymers, asphalt emulsions, concrete, AM-9, and sodium silicate-calcium chloride-foramide grouts. The applications were second containment (or leak prevention) of subsurface waste tanks and piping, grouting water wells to prevent contamination leaking to the water table, and encompassing cribs, trenches, burial grounds, and other subsurface sediment contaminations. Organic polymers added strength to the soil, but penetration of the viscous liquid was not as deep as desired; it may be good for situations requiring only a few inches penetration, such as well grouting. The asphalt emulsion looked promising as an easily injected well grouting material and it may also be good for encompassing subsurface contaminated sediment plumes. The sodium silicate-calcium chloride-foramide affixant appeared best for second containment of waste tanks but may require the help of asphalt emulsion to ensure good coverage.

  19. Uptake, translocation and elimination in sediment-rooted macrophytes: A model-supported analysis of whole sediment toxicity test data

    NARCIS (Netherlands)

    Diepens, N.J.; Arts, G.H.P.; Focks, A.; Koelmans, A.A.

    2014-01-01

    Understanding bioaccumulation in sediment-rooted macrophytes is crucial for the development of sediment toxicity tests using macrophytes. Here we explore bioaccumulation in sediment-rooted macrophytes by tracking and modelling chemical flows of chlorpyrifos, linuron, and six PCBs in

  20. Ubiquitous presence and novel diversity of anaerobic alkane degraders in cold marine sediments

    Directory of Open Access Journals (Sweden)

    Antje eGittel

    2015-12-01

    Full Text Available Alkanes are major constituents of crude oil and are released to the marine environment by natural seepage and from anthropogenic sources. Due to their chemical inertness, their removal from anoxic marine sediments is primarily controlled by the activity of anaerobic alkane-degrading microorganisms. To conduct a comprehensive cultivation-independent survey of the diversity and distribution of anaerobic alkane degraders, we designed novel PCR primers that cover all known diversity of the 1-methylalkyl succinate synthase gene (masD/assA, which catalyzes the initial activation of alkanes. We studied masD/assA gene diversity in pristine and seepage-impacted Danish coastal sediments, as well as in sediments and alkane-degrading enrichment cultures from the Middle Valley (MV hydrothermal vent system in the Pacific Northwest. MasD/assA genes were ubiquitously present, and the primers captured the diversity of both known and previously undiscovered masD/assA gene diversity. Seepage sediments were dominated by a single masD/assA gene cluster, which is presumably indicative of a substrate-adapted community, while pristine sediments harbored a diverse range of masD/assA phylotypes including those present in seepage sediments. This rare biosphere of anaerobic alkane degraders will likely increase in abundance in the event of seepage or accidental oil spillage. Nanomolar concentrations of short-chain alkanes (SCA were detected in pristine and seepage sediments. Interestingly, anaerobic alkane degraders closely related to strain BuS5, the only SCA degrader in pure culture, were found in mesophilic MV enrichments, but not in cold sediments from Danish waters. We propose that the new masD/assA gene lineages in these sediments represent novel phylotypes that are either fueled by naturally occurring low levels of SCA or that metabolize medium- to long-chain alkanes. Our study highlights that masD/assA genes are a relevant diagnostic marker to identify seepage and

  1. Selecting Color-based Tracers and Classifying Sediment Sources in the Assessment of Sediment Dynamics Using Sediment Source Fingerprinting.

    Science.gov (United States)

    Barthod, Louise R M; Liu, Kui; Lobb, David A; Owens, Philip N; Martínez-Carreras, Núria; Koiter, Alexander J; Petticrew, Ellen L; McCullough, Gregory K; Liu, Cenwei; Gaspar, Leticia

    2015-09-01

    The use of sediment color as a fingerprint property to determine sediment sources is an emerging technique that can provide a rapid and inexpensive means of investigating sediment sources. The present study aims to test the feasibility of color fingerprint properties to apportion sediment sources within the South Tobacco Creek Watershed (74 km) in Manitoba, Canada. Suspended sediment from 2009 to 2011 at six monitoring stations and potential source samples along the main stem of the creek were collected. Reflectance spectra of sediments and source materials were quantified using a diffuse reflectance spectrometry, and 16 color coefficients were derived from several color space models. Canonical discriminant analysis was used to reclassify and downsize sediment source groups. After the linear additive test and stepwise discriminant function analysis, four color coefficients were chosen to fit the Stable Isotope Analysis in R model. Consistent with the conventional fingerprinting approach, the color fingerprint results demonstrated a switch in the dominant sediment source between the headwaters and the outlet of the watershed, with the main sources being topsoil in the upper reaches, whereas outcrop shale and stream bank materials dominated in the lower reaches. The color fingerprinting approach can be integrated with conventional fingerprints (e.g., geochemical and fallout radionuclide properties) to improve source discrimination, which is a key component for source ascription modeling. We concluded that the use of color fingerprints is a promising, cost-effective technique for sediment source fingerprinting. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  2. Light-dependant biostabilisation of sediments by stromatolite assemblages.

    Science.gov (United States)

    Paterson, David M; Aspden, Rebecca J; Visscher, Pieter T; Consalvey, Mireille; Andres, Miriam S; Decho, Alan W; Stolz, John; Reid, R Pamela

    2008-09-10

    For the first time we have investigated the natural ecosystem engineering capacity of stromatolitic microbial assemblages. Stromatolites are laminated sedimentary structures formed by microbial activity and are considered to have dominated the shallows of the Precambrian oceans. Their fossilised remains are the most ancient unambiguous record of early life on earth. Stromatolites can therefore be considered as the first recognisable ecosystems on the planet. However, while many discussions have taken place over their structure and form, we have very little information on their functional ecology and how such assemblages persisted despite strong eternal forcing from wind and waves. The capture and binding of sediment is clearly a critical feature for the formation and persistence of stromatolite assemblages. Here, we investigated the ecosystem engineering capacity of stromatolitic microbial assemblages with respect to their ability to stabilise sediment using material from one of the few remaining living stromatolite systems (Highborne Cay, Bahamas). It was shown that the most effective assemblages could produce a rapid (12-24 h) and significant increase in sediment stability that continued in a linear fashion over the period of the experimentation (228 h). Importantly, it was also found that light was required for the assemblages to produce this stabilisation effect and that removal of assemblage into darkness could lead to a partial reversal of the stabilisation. This was attributed to the breakdown of extracellular polymeric substances under anaerobic conditions. These data were supported by microelectrode profiling of oxygen and calcium. The structure of the assemblages as they formed was visualised by low-temperature scanning electron microscopy and confocal laser microscopy. These results have implications for the understanding of early stromatolite development and highlight the potential importance of the evolution of photosynthesis in the mat forming process

  3. Sediment Mobilization in Ravines Draining Minnesota Cropland

    Science.gov (United States)

    Choquette, A. W.; Triplett, L.; Gran, K. B.

    2013-12-01

    In recent years, studies have found that Lake Pepin, a naturally-dammed lake on the Mississippi River on the border of Minnesota and Wisconsin, is filling in with sediment at an alarming rate. Most of this sediment comes from the Minnesota River, which contributes about 80% of all the sediment being deposited in Lake Pepin, even though it contains only 35% of the upstream area. This study focuses on understanding sediment derived from ravine erosion in a tributary of the Minnesota River basin through event monitoring of two ravines in the Le Sueur River watershed. Ravines represent one of the key sediment sources in the Le Sueur watershed, with sediment mobilized through ravine widening and headcutting. In addition, sediment may be mobilized through riverbank and bluff erosion and erosion of the topsoil. A major effort is underway to reduce the amount of sediment in the Minnesota River and Lake Pepin, so we must discover what is causing the sediment to be mobilized and when. Dominant land use in the area is agricultural with over 90% of the crops consisting of row crops. Field drainage in these agricultural areas is heavily influenced by the installation of drainage ditches and drain tile. While this has increased crop yield, it has altered the natural drainage of the area. Southern Minnesota is covered by a thick layer of glacial till allowing the landscape to rapidly respond to hydrologic conditions within a relatively short amount of time, and those changes could include ravine widening or elongation. To better understand how ravines respond to different hydrologic events, we monitored ravines over the course of one monitoring season. From April-October 2013, three Sigma 930 automated samplers measured discharge and collected water samples for total suspended sediment analysis at three sites in two ravines. We tested whether the volume, intensity or seasonality of precipitation events is most important in mobilizing sediment in the ravines. Data are being

  4. Controls on flood and sediment wave propagation

    Science.gov (United States)

    Bakker, Maarten; Lane, Stuart N.; Costa, Anna; Molnar, Peter

    2015-04-01

    The understanding of flood wave propagation - celerity and transformation - through a fluvial system is of generic importance for flood forecasting/mitigation. In association with flood wave propagation, sediment wave propagation may induce local erosion and sedimentation, which will affect infrastructure and riparian natural habitats. Through analysing flood and sediment wave propagation, we gain insight in temporal changes in transport capacity (the flood wave) and sediment availability and transport (the sediment wave) along the river channel. Heidel (1956) was amongst the first to discuss the progressive lag of sediment concentration behind the corresponding flood wave based on field measurements. Since then this type of hysteresis has been characterized in a number of studies, but these were often based on limited amount of floods and measurement sites, giving insufficient insight into associated forcing mechanisms. Here, as part of a project concerned with the hydrological and geomorphic forcing of sediment transfer processes in alpine environments, we model the downstream propagation of short duration, high frequency releases of water and sediment (purges) from a flow intake in the Borgne d'Arolla River in south-west Switzerland. A total of >50 events were measured at 1 minute time intervals using pressure transducers and turbidity probes at a number of sites along the river. We show that flood and sediment wave propagation can be well represented through simple convection diffusion models. The models are calibrated/validated to describe the set of measured waves and used to explain the observed variation in wave celerity and diffusion. In addition we explore the effects of controlling factors including initial flow depth, flood height, flood duration, bed roughness, bed slope and initial sediment concentration, on the wave propagation processes. We show that the effects of forcing mechanisms on flood and sediment wave propagation will lead to different

  5. Temporal variability of suspended sediment sources in an alpine catchment combining river/rainfall monitoring and sediment fingerprinting

    OpenAIRE

    Navratil, O.; Evrard, O.; Esteves, Michel; Legout, C.; Ayrault, S.; Nemery, J.; Mate-Marin, A.; Ahmadi, M.; Lefevre, I.; Poirel, A.; Bonte, P.

    2012-01-01

    Influence of the rainfall regime on erosion and transfer of suspended sediment in a 905-km(2) mountainous catchment of the southern French Alps was investigated by combining sediment monitoring, rainfall data, and sediment fingerprinting (based on geochemistry and radionuclide concentrations). Suspended sediment yields were monitored between October 2007 and December 2009 in four subcatchments (22-713km(2)). Automatic sediment sampling was triggered during floods to trace the sediment origin ...

  6. The hydraulic conductivity of sediments: A pore size perspective

    KAUST Repository

    Ren, X.W.

    2017-12-06

    This article presents an analysis of previously published hydraulic conductivity data for a wide range of sediments. All soils exhibit a prevalent power trend between the hydraulic conductivity and void ratio. Data trends span 12 orders of magnitude in hydraulic conductivity and collapse onto a single narrow trend when the hydraulic conductivity data are plotted versus the mean pore size, estimated using void ratio and specific surface area measurements. The sensitivity of hydraulic conductivity to changes in the void ratio is higher than the theoretical value due to two concurrent phenomena: 1) percolating large pores are responsible for most of the flow, and 2) the larger pores close first during compaction. The prediction of hydraulic conductivity based on macroscale index parameters in this and similar previous studies has reached an asymptote in the range of kmeas/5≤kpredict≤5kmeas. The remaining uncertainty underscores the important role of underlying sediment characteristics such as pore size distribution, shape, and connectivity that are not measured with index properties. Furthermore, the anisotropy in hydraulic conductivity cannot be recovered from scalar parameters such as index properties. Overall, results highlight the robustness of the physics inspired data scrutiny based Hagen–Poiseuille and Kozeny-Carman analyses.

  7. Shifts in coastal sediment oxygenation cause pronounced changes in microbial community composition and associated metabolism.

    Science.gov (United States)

    Broman, Elias; Sjöstedt, Johanna; Pinhassi, Jarone; Dopson, Mark

    2017-08-09

    A key characteristic of eutrophication in coastal seas is the expansion of hypoxic bottom waters, often referred to as 'dead zones'. One proposed remediation strategy for coastal dead zones in the Baltic Sea is to mix the water column using pump stations, circulating oxygenated water to the sea bottom. Although microbial metabolism in the sediment surface is recognized as key in regulating bulk chemical fluxes, it remains unknown how the microbial community and its metabolic processes are influenced by shifts in oxygen availability. Here, coastal Baltic Sea sediments sampled from oxic and anoxic sites, plus an intermediate area subjected to episodic oxygenation, were experimentally exposed to oxygen shifts. Chemical, 16S rRNA gene, metagenomic, and metatranscriptomic analyses were conducted to investigate changes in chemistry fluxes, microbial community structure, and metabolic functions in the sediment surface. Compared to anoxic controls, oxygenation of anoxic sediment resulted in a proliferation of bacterial populations in the facultative anaerobic genus Sulfurovum that are capable of oxidizing toxic sulfide. Furthermore, the oxygenated sediment had higher amounts of RNA transcripts annotated as sqr, fccB, and dsrA involved in sulfide oxidation. In addition, the importance of cryptic sulfur cycling was highlighted by the oxidative genes listed above as well as dsvA, ttrB, dmsA, and ddhAB that encode reductive processes being identified in anoxic and intermediate sediments turned oxic. In particular, the intermediate site sediments responded differently upon oxygenation compared to the anoxic and oxic site sediments. This included a microbial community composition with more habitat generalists, lower amounts of RNA transcripts attributed to methane oxidation, and a reduced rate of organic matter degradation. These novel data emphasize that genetic expression analyses has the power to identify key molecular mechanisms that regulate microbial community responses

  8. Artificialized land characteristics and sediment connectivity explain muddy flood hazard in Wallonia

    Science.gov (United States)

    de Walque, Baptiste; Bielders, Charles; Degré, Aurore; Maugnard, Alexandre

    2017-04-01

    Muddy flood occurrence is an off-site erosion problem of growing interest in Europe and in particular in the loess belt and Condroz regions of Wallonia (Belgium). In order to assess the probability of occurrence of muddy floods in specific places, a muddy flood hazard prediction model has been built. It was used to test 11 different explanatory variables in simple and multiple logistic regressions approaches. A database of 442 muddy flood-affected sites and an equal number of homologous non flooded sites was used. For each site, relief, land use, sediment production and sediment connectivity of the contributing area were extracted. To assess the prediction quality of the model, we proceeded to a validation using 48 new pairs of homologous sites. Based on Akaïke Information Criterion (AIC), we determined that the best muddy flood hazard assessment model requires a total of 6 explanatory variable as inputs: the spatial aggregation of the artificialized land, the sediment connectivity, the artificialized land proximity to the outlet, the proportion of artificialized land, the mean slope and the Gravelius index of compactness of the contributive area. The artificialized land properties listed above showed to improve substantially the model quality (p-values from 10e-10 to 10e-4). All of the 3 properties showed negative correlation with the muddy flood hazard. These results highlight the importance of considering the artificialized land characteristics in the sediment transport assessment models. Indeed, artificialized land such as roads may dramatically deviate flows and influence the connectivity in the landscape. Besides the artificialized land properties, the sediment connectivity showed significant explanatory power (p-value of 10e-11). A positive correlation between the sediment connectivity and the muddy flood hazard was found, ranging from 0.3 to 0.45 depending on the sediment connectivity index. Several studies already have highlighted the importance of this

  9. Sediment Resuspension and Deposition on Seagrass Leaves Impedes Internal Plant Aeration and Promotes Phytotoxic H2S Intrusion

    Directory of Open Access Journals (Sweden)

    Kasper E. Brodersen

    2017-05-01

    Full Text Available HIGHLIGHTS:Sedimentation of fine sediment particles onto seagrass leaves severely hampers the plants' performance in both light and darkness, due to inadequate internal plant aeration and intrusion of phytotoxic H2S.Anthropogenic activities leading to sediment re-suspension can have adverse effects on adjacent seagrass meadows, owing to reduced light availability and the settling of suspended particles onto seagrass leaves potentially impeding gas exchange with the surrounding water. We used microsensors to determine O2 fluxes and diffusive boundary layer (DBL thickness on leaves of the seagrass Zostera muelleri with and without fine sediment particles, and combined these laboratory measurements with in situ microsensor measurements of tissue O2 and H2S concentrations. Net photosynthesis rates in leaves with fine sediment particles were down to ~20% of controls without particles, and the compensation photon irradiance increased from a span of 20–53 to 109–145 μmol photons m−2 s−1. An ~2.5-fold thicker DBL around leaves with fine sediment particles impeded O2 influx into the leaves during darkness. In situ leaf meristematic O2 concentrations of plants exposed to fine sediment particles were lower than in control plants and exhibited long time periods of complete meristematic anoxia during night-time. Insufficient internal aeration resulted in H2S intrusion into the leaf meristematic tissues when exposed to sediment resuspension even at relatively high night-time water-column O2 concentrations. Fine sediment particles that settle on seagrass leaves thus negatively affect internal tissue aeration and thereby the plants' resilience against H2S intrusion.

  10. Understanding Sediment Sources, Pathways, and Sinks in Regional Sediment Management: Application of Wash Load and Bed-Material Load Concept

    National Research Council Canada - National Science Library

    Biedenham, David S; Hubbard, Lisa C; Thome, Colin R; Watson, Chester C

    2006-01-01

    ... through the fluvial system for sediments derived from various bed, bank, gully, and catchment sources thereby providing a reliable analytical foundation for effective regional sediment management...

  11. Prokaryotic Community Composition in Arctic Kongsfjorden and Sub-Arctic Northern Bering Sea Sediments As Revealed by 454 Pyrosequencing

    Directory of Open Access Journals (Sweden)

    Yin-Xin Zeng

    2017-12-01

    abundance of particular archaeal species (e.g., Candidatus Nitrosopumilus and Methanococcoides or bacterial species (e.g., Sulfurimonas, Sulfurovum, and Desulfobulbaceae involved in biogeochemical cycles were also observed among sediment samples. At the same time, despite the community variation, some phylotypes (e.g., Marinicella were dominant in all sediments. This study indicates diverse microbial communities inhabiting pan-arctic marine sediments, and highlights potential roles for Archaea and Bacteria in global biogeochemical cycles in these environments.

  12. Dense colloidal fluids form denser amorphous sediments.

    Science.gov (United States)

    Liber, Shir R; Borohovich, Shai; Butenko, Alexander V; Schofield, Andrew B; Sloutskin, Eli

    2013-04-09

    We relate, by simple analytical centrifugation experiments, the density of colloidal fluids with the nature of their randomly packed solid sediments. We demonstrate that the most dilute fluids of colloidal hard spheres form loosely packed sediments, where the volume fraction of the particles approaches in frictional systems the random loose packing limit, ϕRLP = 0.55. The dense fluids of the same spheres form denser sediments, approaching the so-called random close packing limit, ϕRCP = 0.64. Our experiments, where particle sedimentation in a centrifuge is sufficiently rapid to avoid crystallization, demonstrate that the density of the sediments varies monotonically with the volume fraction of the initial suspension. We reproduce our experimental data by simple computer simulations, where structural reorganizations are prohibited, such that the rate of sedimentation is irrelevant. This suggests that in colloidal systems, where viscous forces dominate, the structure of randomly close-packed and randomly loose-packed sediments is determined by the well-known structure of the initial fluids of simple hard spheres, provided that the crystallization is fully suppressed.

  13. Equilibrium Partitioning Sediment Benchmarks (ESBs) for the ...

    Science.gov (United States)

    This document describes procedures to determine the concentrations of nonionic organic chemicals in sediment interstitial waters. In previous ESB documents, the general equilibrium partitioning (EqP) approach was chosen for the derivation of sediment benchmarks because it accounts for the varying bioavailability of chemicals in different sediments and allows for the incorporation of the appropriate biological effects concentration. This provides for the derivation of benchmarks that are causally linked to the specific chemical, applicable across sediments, and appropriately protective of benthic organisms.  This equilibrium partitioning sediment benchmark (ESB) document was prepared by scientists from the Atlantic Ecology Division, Mid-Continent Ecology Division, and Western Ecology Division, the Office of Water, and private consultants. The document describes procedures to determine the interstitial water concentrations of nonionic organic chemicals in contaminated sediments. Based on these concentrations, guidance is provided on the derivation of toxic units to assess whether the sediments are likely to cause adverse effects to benthic organisms. The equilibrium partitioning (EqP) approach was chosen because it is based on the concentrations of chemical(s) that are known to be harmful and bioavailable in the environment.  This document, and five others published over the last nine years, will be useful for the Program Offices, including Superfund, a

  14. Assessing contamination in Great Lakes sediments using benthic invertebrate communities and the sediment quality triad approach

    Science.gov (United States)

    Canfield, Timothy J.; Dwyer, F. James; Fairchild, James F.; Haverland, Pamela S.; Ingersoll, Christopher G.; Kemble, Nile E.; Mount, David R.; La Point, Thomas W.; Burton, G. Allen; Swift, M. C.

    1996-01-01

    Sediments in many Great Lakes harbors and tributary rivers are contaminated. As part of the USEPA's Assessment and Remediation of Contaminated Sediment (ARCS) program, a number of studies were conducted to determine the nature and extent of sediment contamination in Great Lakes Areas of Concern (AOC). This paper describes the composition of benthic invertebrate communities in contaminated sediments and is one in a series of papers describing studies conducted to evaluate sediment toxicity from three AOC's (Buffalo River, NY; Indiana Harbor, IN; Saginaw River, MI), as part of the ARCS Program. Oligochaeta (worms) and Chironomidae (midge) comprised over 90% of the benthic invertebrate numbers in samples collected from depositional areas. Worms and midge consisted of taxa identified as primarily contaminant tolerant organisms. Structural deformities of mouthparts in midge larvae were pronounced in many of the samples. Good concurrence was evident between measures of laboratory toxicity, sediment contaminant concentration, and benthic invertebrate community composition in extremely contaminated samples. However, in moderately contaminated samples, less concordance was observed between the benthos community composition and either laboratory toxicity test results or sediment contaminant concentration. Laboratory sediment toxicity tests may better identify chemical contamination in sediments than many commonly used measures of benthic invertebrate community composition. Benthic measures may also reflect other factors such as habitat alteration. Evaluation of non-contaminant factors are needed to better interpret the response of benthic invertebrates to sediment contamination.

  15. Assessment of contaminated sediments with an indoor freshwater/sediment microcosm assay.

    Science.gov (United States)

    Triffault-Bouchet, Gaëlle; Clément, Bernard; Blake, Gérard

    2005-09-01

    This study was conducted to assess the feasibility of using a 2-L, indoor microcosm assay to evaluate five contaminated sediments (A, B, C, D, and E). Toxic potential was deduced in the light of general contamination of sediments, pollutant partitioning in microcosms, and biological responses of species (Pseudokirchneriella subcapitata, Lemna minor, Daphnia magna, Hyalella azteca, Chironomus riparius): E > A > B > C > D. Sediments mainly were contaminated by metals (lead and zinc). Organic pollutant contents varied among the sediments. The major polycyclic aromatic hydrocarbon (PAH) compounds were pyrene, fluoranthene, and phenanthrene. Sediments A, B, and C highly stimulated duckweed growth (> 700%) and impaired daphnid (< 20%) and amphipod survival (< 30%). Sediment D had no significant effect on pelagic and benthic organisms. Finally, sediment E, the most toxic, limited duckweed growth (inhibition of 82%) and impaired daphnid survival (0% of survival). Amphipods were impaired dramatically by this sediment (0% of survival), in contrast with chironomids, for which no toxic effect was measured. The 2-L, indoor microcosm assay successfully was applied to the assessment of those five contaminated sediments. Sediments A, B, C, and E should not be deposited in gravel quarries, and new, more sensitive endpoint measurements should be developed.

  16. Suspended-sediment loads and reservoir sediment trap efficiency for Clinton Lake, Kansas, 2010-12

    Science.gov (United States)

    Juracek, Kyle E.

    2013-01-01

    Continuous streamflow and turbidity data collected from October 1, 2010, to September 30, 2012, at a site upstream and downstream from Clinton Lake, Kansas, were used to compute the total suspended-sediment load delivered to and released from the reservoir as well as the sediment trap efficiency for the reservoir. Ongoing sedimentation is inhibiting the ability of Clinton Lake to serve several purposes including flood control, water supply, and recreation. The inflow suspended-sediment load was substantially larger than the outflow load and most of the suspended-sediment load was delivered during short-term, high-discharge periods. Respectively, the total 2-year inflow and outflow suspended-sediment loads were computed to be 44.4 and 1.49 million pounds. Sediment trap efficiency for the reservoir was estimated to be 97 percent. The mean annual suspended-sediment yield from the upstream basin was estimated to be 60,500 pounds per square mile. Because this study was completed during a drought, the estimated inflow suspended-sediment load and suspended-sediment yield likely are substantially less than what would occur during a period of average or above average precipitation and runoff.

  17. Estuarine Sediment Dissolved Organic Matter Dynamics in an Enhanced Sediment Flux Model

    Science.gov (United States)

    Clark, J. Blake; Long, Wen; Hood, Raleigh R.

    2017-10-01

    Sediment derived dissolved organic matter (DOM) can comprise a substantial portion of the organic carbon budget in coastal bottom waters, yet it is often neglected in coastal carbon cycle models. In most modern sediment-water column flux models, biologically mediated reactions that remineralize particulate organic matter (POM) into inorganic compounds are simplified. In reality, organic matter remineralization is a complex suite of reactions that include DOM intermediate compounds. To better represent the sequential breakdown of POM and remineralization of DOM, a DOM state variable was built into a widely used sediment flux model. In the model, DOM is created in the sediment by hydrolysis of POM, and all organic matter passes through the DOM pool before remineralization. The model was run for 11 years and tuned to reproduce observed sediment flux data collected in Chesapeake Bay and then used to assess the role of DOM in sediment organic matter dynamics. Sediment-water column fluxes of DOM are highly variable both on seasonal and interannual scales, with substantial variability among stations in both magnitude and flux direction. Across all stations, semilabile and inert DOM is lost and labile DOM is taken up into the reactive first layer of the modeled sediment, with the net flux a balance of the two processes. The improved sediment flux model can be utilized to better understand the role of sediment biogeochemistry in the estuarine and coastal carbon cycle and shed light on difficult to measure processes involving DOM intermediate compounds.

  18. Tourette syndrome research highlights from 2016 [version 2; referees: 4 approved

    Directory of Open Access Journals (Sweden)

    Kevin J. Black

    2017-11-01

    Full Text Available This article presents highlights chosen from research that appeared during 2016 on Tourette syndrome and other tic disorders. Selected articles felt to represent meaningful advances in the field are briefly summarized.

  19. Tourette syndrome research highlights from 2016 [version 1; referees: 2 approved, 1 approved with reservations

    Directory of Open Access Journals (Sweden)

    Kevin J. Black

    2017-08-01

    Full Text Available This article presents highlights chosen from research that appeared during 2016 on Tourette syndrome and other tic disorders. Selected articles felt to represent meaningful advances in the field are briefly summarized.

  20. Symposium on Highlights from 14 years of LEAR Physics : "AD Project" by S. Maury

    CERN Multimedia

    1998-01-01

    Symposium on Highlights from 14 years of LEAR Physics hold at CERN, commemorating the closure of LEAR and giving a topical review of the impact of experiments with low energy antiprotons in their respective fields: S. Maury "AD Project"