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Sample records for mackenzie delta nwt

  1. Mackenzie River Delta, Canada

    NASA Technical Reports Server (NTRS)

    2007-01-01

    The Mackenzie River in the Northwest Territories, Canada, with its headstreams the Peace and Finley, is the longest river in North America at 4241 km, and drains an area of 1,805,000 square km. The large marshy delta provides habitat for migrating Snow Geese, Tundra Swans, Brant, and other waterfowl. The estuary is a calving area for Beluga whales. The Mackenzie (previously the Disappointment River) was named after Alexander Mackenzie who travelled the river while trying to reach the Pacific in 1789.

    The image was acquired on August 4, 2005, covers an area of 55.8 x 55.8 km, and is located at 68.6 degrees north latitude, 134.7 degrees west longitude.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  2. Passive acoustic derived bubble flux and applications to natural gas seepage in the Mackenzie Delta, NWT, Canada and Coal Oil Point, CA

    NASA Astrophysics Data System (ADS)

    Culling, D.; Leifer, I.; Dallimore, S.; Alcala, K.

    2012-12-01

    Minnaert equation predicts. Furthermore, bubbles from a cohesive media escaped in pulses of multiple bubbles, which caused significant inter-bubble acoustic coupling and mud-bubble interaction. The acoustic signature of subsurface bubble migration and concurrent sediment movements, including bubble pinch off, presented additional complexities. Use of passive acoustic derived flux was applied to natural gas seepage in the Mackenzie Delta in the North West Territories, Canada as well as offshore Coal Oil Point (COP), CA. Video data were used to calibrate the COP acoustic observations and showed a strong current impact for non-cohesive sediments. Seepage flux in the delta (cohesive sediments) was calibrated using a custom turbine tent that directly measured flux. Further applications of passive acoustic-derived seep fluxes include monitoring of marine pipelines for leaks, and studying biogenic wetlands ebullition as well as thermogenic and hydrate seepage.

  3. Overview of the science activities for the 2002 Mallik gas hydrate production research well program, Mackenzie Delta, N.W.T., Canada

    NASA Astrophysics Data System (ADS)

    Dallimore, S. R.; Collett, T. S.; Uchida, T.; Weber, M.

    2003-04-01

    With the completion of scientific studies undertaken as part of the 1998 Mallik 2L-38 gas hydrate research well, an international research site was established for the study of Arctic natural gas hydrates in the Mackenzie Delta of northwestern Canada. Quantitative well log analysis and core studies reveal multiple gas hydrate layers from 890 m to 1106 m depth, exceeding 110 m in total thickness. High gas hydrate saturation values, which in some cases exceed 80% of the pore volume, establish the Mallik gas hydrate field as one of the most concentrated gas hydrate reservoirs in the world. Beginning in December 2001 and continuing to the middle of March 2002, two 1188 m deep science observation wells were drilled and instrumented and a 1166 m deep production research well program was carried out. The program participants include 8 partners; The Geological Survey of Canada (GSC), The Japan National Oil Corporation (JNOC), GeoForschungsZentrum Potsdam (GFZ), United States Geological Survey (USGS), United States Department of the Energy (USDOE), India Ministry of Petroleum and Natural Gas (MOPNG)/Gas Authority of India (GAIL) and the Chevron-BP-Burlington joint venture group. In addition the project has been accepted as part of the International Scientific Continental Drilling Program. The Geological Survey of Canada is coordinating the science program for the project and JAPEX Canada Ltd. acted as the designated operator for the fieldwork. Primary objectives of the research program are to advance fundamental geological, geophysical and geochemical studies of the Mallik gas hydrate field and to undertake advanced production testing of a concentrated gas hydrate reservoir. Full-scale field experiments in the production well monitored the physical behavior of the hydrate deposits in response to depressurization and thermal stimulation. The observation wells facilitated cross-hole tomography and vertical seismic profile experiments (before and after production) as well as

  4. Proterozoic Carbonate Lithofacies Control the Distribution of Sulphides at the Gayna River Zn-Pb Camp, Mackenzie Mountains, NWT

    NASA Astrophysics Data System (ADS)

    Turner, E. C.

    2009-05-01

    Zn-Pb deposits at Gayna River, NWT are predominantly concentrated in the informal 'Grainstone formation', a dolostone of the early Neoproterozoic Little Dal Group (Mackenzie Mountains Supergroup). Previous work showed that the mineralisation (inferred 50 Mt combined from numerous zones; 5 percent combined Zn+Pb) is fracture-controlled and spatially associated with giant stromatolite reefs (500 m thick) of the underlying formation. The rheologically brittle, uncompactable and hydrologically tight reef masses are enclosed by coeval, compacted shale and deep-water limestone. A long and complex history of reef growth controlled by sea-level change resulted in a distinctive reef morphology that includes a sharp right-angle at all reef-top margins, where heterogeneous, off-reef limestone, shale and dolostone abut the rigid, lithologically homogeneous reefs. These zones of abrupt lateral facies change, between uncompactable reef and ductile, layered off-reef strata, represent the structurally weakest points in the system, where, during even subtle later tectonic events, stress would be preferentially accommodated. Brittle deformation of competent carbonate layers in this inflection zone in response to stress produced fracture haloes around reef-tops, which were then occluded by Zn-Pb sulphides. Abrupt competence contrasts appear to be necessary for the production of fractures that control the locations of sulphides at Gayna River. The dominant fractures in the Gayna River camp are those associated with reef- tops. The plan shape and location of buried reef-tops are probably the most critical controls on the distribution of hitherto undiscovered sulphide masses in the subsurface. Careful mapping of those depositional lithofacies that are characteristic of near-reef environments and of subtle, compaction-related dips in appropriate stratigraphic levels may provide vectors to as-yet unrecognised subsurface reef-margin zones favourable for Zn-Pb mineralisation. Structures and

  5. Nearshore Circulation and Storm Surge Along the Mackenzie Delta Coast

    NASA Astrophysics Data System (ADS)

    Perrie, W.; Mulligan, R. P.; Solomon, S. M.; Hoque, A.; Zhang, L.

    2008-12-01

    The Mackenzie Delta is a 150 km long section of coastline characterized by muddy sediments where the Mackenzie River outflow, dispersed over 20 distributary channels, discharges into the southern Beaufort Sea. The marine environment in this region is an important and integral part of the lives of Canadian Northerners. The area is also undergoing hydrocarbon exploration with potential development within the next decade. Changes to Arctic climate, such as increasing ice-free western Arctic Ocean and intensifying storm activity, may endanger the coastal settlements and marine environment in the Mackenzie Delta region. The low gradient of the delta and the adjacent inner shelf makes it very susceptible to flooding during storms. Field observations in the nearshore zone collected in August of 2007 and 2008 indicate strong gradients in temperature and salinity in shallow water of 2-6 m. The fluctuations are associated with the movements of warm and fresh river plumes and wind-driven upwelling of cold and saline water below the thermocline. The observations are in agreement with 3D model simulations of the nearshore delta region using Delft3D, which includes wind, tidal, storm surge, buoyancy and river forcing. The results validate the model and indicate that it can be used to hindcast the nearshore oceanographic conditions during severe Arctic storms. As a case study we present preliminary model results for an Arctic storm from late 1999 that caused extensive vegetation die-off in the outer delta. This cyclone was a mesoscale Arctic storm that developed over the NE Pacific and western Bering Sea, intensified explosively in the Gulf of Alaska and developed into a meteorological bomb. The storm made landfall at Cape Newenham, Alaska, crossed the Rocky Mountains to the Yukon and Northwest Territories and re-intensified over a zone of high sea surface temperature gradients in the southern Beaufort Sea. Using the Canadian Mesoscale Compressible Community (MC2) atmospheric

  6. Mackenzie River Delta morphological change based on Landsat time series

    NASA Astrophysics Data System (ADS)

    Vesakoski, Jenni-Mari; Alho, Petteri; Gustafsson, David; Arheimer, Berit; Isberg, Kristina

    2015-04-01

    Arctic rivers are sensitive and yet quite unexplored river systems to which the climate change will impact on. Research has not focused in detail on the fluvial geomorphology of the Arctic rivers mainly due to the remoteness and wideness of the watersheds, problems with data availability and difficult accessibility. Nowadays wide collaborative spatial databases in hydrology as well as extensive remote sensing datasets over the Arctic are available and they enable improved investigation of the Arctic watersheds. Thereby, it is also important to develop and improve methods that enable detecting the fluvio-morphological processes based on the available data. Furthermore, it is essential to reconstruct and improve the understanding of the past fluvial processes in order to better understand prevailing and future fluvial processes. In this study we sum up the fluvial geomorphological change in the Mackenzie River Delta during the last ~30 years. The Mackenzie River Delta (~13 000 km2) is situated in the North Western Territories, Canada where the Mackenzie River enters to the Beaufort Sea, Arctic Ocean near the city of Inuvik. Mackenzie River Delta is lake-rich, productive ecosystem and ecologically sensitive environment. Research objective is achieved through two sub-objectives: 1) Interpretation of the deltaic river channel planform change by applying Landsat time series. 2) Definition of the variables that have impacted the most on detected changes by applying statistics and long hydrological time series derived from Arctic-HYPE model (HYdrologic Predictions for Environment) developed by Swedish Meteorological and Hydrological Institute. According to our satellite interpretation, field observations and statistical analyses, notable spatio-temporal changes have occurred in the morphology of the river channel and delta during the past 30 years. For example, the channels have been developing in braiding and sinuosity. In addition, various linkages between the studied

  7. Mercury in the Mackenzie River delta and estuary: concentrations and fluxes during open-water conditions.

    PubMed

    Graydon, Jennifer A; Emmerton, Craig A; Lesack, Lance F W; Kelly, Erin N

    2009-04-01

    Estimates of mercury (Hg) loadings to the Arctic Ocean from circumpolar rivers have not considered biogeochemical changes that occur when river water is temporarily stored in large deltas (delta effect). There are also few data describing Hg changes across the freshwater-saltwater transition zone (FSTZ) of these rivers. We assessed temporal changes in unfiltered total mercury (THg) and methylmercury (MeHg) concentrations during open-water 2004 in the Mackenzie River upstream of the Mackenzie River delta, and in 6 floodplain lakes across an elevation gradient. These data were used to calculate Hg fluxes from the Mackenzie River and to evaluate a delta effect on Hg using an estimate of delta river water storage and a mixing analysis. Mean THg concentrations were highest in river water (9.17+/-5.51 ng/L) and decreased up the lake elevation gradient. Mean MeHg concentrations were highest in lakes periodically connected to the river (0.213+/-0.122 ng/L) and MeHg concentrations in elevated lakes showed a mid-summer peak. Results from the mixing analysis showed that the delta effect may be large enough to affect Hg loadings to the Arctic Ocean. THg concentrations exiting the delta (10.2 ng/L) were 16% lower than those entering (12.1 ng/L), whereas MeHg showed little change. We calculated 2.5-month (open-water) THg and MeHg fluxes from the Mackenzie River of 1208 and 8.4 kg. These fluxes are similar in magnitude to previous annual estimates in the arctic literature suggesting that previously published annual Hg fluxes from the Mackenzie River may be large underestimates. We also assessed changes in Mackenzie River water THg and MeHg concentrations as it crossed the FSTZ during an open-water cruise. THg decreased non-conservatively across the estuary from 3.8-0.6 ng/L, possibly due to mixing and particle settling. MeHg concentrations were variable and near detection. Our results show that the Mackenzie River estuary is a dynamic environment and may have important controls

  8. Origin of polycyclic aromatic hydrocarbons in lake sediments of the Mackenzie Delta.

    PubMed

    Headley, John V; Marsh, Philip; Akre, Christine J; Peru, Kerry M; Lesack, Lance

    2002-08-01

    The concentrations and distribution of polycyclic aromatic hydrocarbons (PAHs) were assessed in sediment cores from among 14 lakes from three regions comprising a transect across the central Mackenzie Delta. PAHs were consistently found in the lake sediments, with parent concentrations in the 20-200 ng/g range. Concentrations were generally independent of depth in the sediment cores and this pattern was similar among the 3 regions of the delta. Concentrations increased in a westerly direction among the regions. For some lakes, the concentration of PAHs decreased with decreasing flooding frequency, and decreasing sedimentation rates. For the latter, maximum concentrations occurred at shallower depths within the sediment cores as flooding frequency among the lakes decreased. The distributions of C0-C4 alkylated 2- and 3- ring PAHs were consistent with a petrogenic origin, while the corresponding distribution of 4-ring PAHs appears to be more consistent with a biogenic or pyrogenic origin. Based on relative contributions to the overall PAH budget, a petrogenic source appears to be dominant. However, the pyrene/fluoranthene ratio is more consistent with a source derived from peat. The alkylated PAH profiles are inconsistent with those in the Athabasca River system, and supports a previously published hypothesis that the contribution of PAHs from the Athabasca oil sands to the lower Mackenzie River is minimal. A double ratio plot of chrysene vs dibenzothiophene, diagnostic of weathering, suggests most weathering occurred before the sediments were deposited in the lakes, while a double ratio plot of dibenzothiophene vs phenanthrene suggests a common source of PAHs across the delta, despite differing water sources from east to west across the delta. PAH inputs to the delta appear to mirror sediment inputs documented in previous work, where high sediment input from the Mackenzie mainstem during high floods dominates the delta sediment influx and masks any influence of the

  9. Investigating the spatial distribution of water levels in the Mackenzie Delta using airborne LiDAR

    USGS Publications Warehouse

    Hopkinson, C.; Crasto, N.; Marsh, P.; Forbes, D.; Lesack, L.

    2011-01-01

    Airborne light detection and ranging (LiDAR) data were used to map water level (WL) and hydraulic gradients (??H/??x) in the Mackenzie Delta. The LiDAR WL data were validated against eight independent hydrometric gauge measurements and demonstrated mean offsets from - 0??22 to + 0??04 m (??< 0??11). LiDAR-based WL gradients could be estimated with confidence over channel lengths exceeding 5-10 km where the WL change exceeded local noise levels in the LiDAR data. For the entire Delta, the LiDAR sample coverage indicated a rate of change in longitudinal gradient (??2H/??x) of 5??5 ?? 10-10 m m-2; therefore offering a potential means to estimate average flood stage hydraulic gradient for areas of the Delta not sampled or monitored. In the Outer Delta, within-channel and terrain gradient measurements all returned a consistent estimate of - 1 ?? 10-5 m m-1, suggesting that this is a typical hydraulic gradient for the downstream end of the Delta. For short reaches (<10 km) of the Peel and Middle Channels in the middle of the Delta, significant and consistent hydraulic gradient estimates of - 5 ?? 10-5 m m-1 were observed. Evidence that hydraulic gradients can vary over short distances, however, was observed in the Peel Channel immediately upstream of Aklavik. A positive elevation anomaly (bulge) of > 0??1 m was observed at a channel constriction entering a meander bend, suggesting a localized modification of the channel hydraulics. Furthermore, water levels in the anabranch channels of the Peel River were almost 1 m higher than in Middle Channel of the Mackenzie River. This suggests: (i) the channels are elevated and have shallower bank heights in this part of the delta, leading to increased cross-delta and along-channel hydraulic gradients; and/or (ii) a proportion of the Peel River flow is lost to Middle Channel due to drainage across the delta through anastamosing channels. This study has demonstrated that airborne LiDAR data contain valuable information describing

  10. Sharing Remote and Local Information for Tracking Spring Breakup in the Mackenzie Delta and Beaufort Sea

    NASA Astrophysics Data System (ADS)

    Forbes, D. L.; Whalen, D.; Fraser, P.

    2015-12-01

    The Mackenzie Delta is the second largest on the Arctic Ocean, covering 13 000 km2. The annual flood regime in the delta is dominated by the spring snowmelt freshet and associated ice breakup, as water from the south arrives in the ice-covered delta and spreads over bottomfast and adjacent floating sea ice at the delta front. The complex processes of water-ice interaction, flow partitioning, and overbank flooding to replenish waters in 43 000 delta lakes threaten community, transportation, subsistence, and energy infrastructure in the delta. The annual breakup season is a time of rejuvenation, excitement, and anxiety for delta residents and stakeholders. To track the progress of breakup and meet the need for knowledge dissemination to the local communities, a Mackenzie-Beaufort breakup newsletter has been produced by Natural Resources Canada on a quasi-daily basis during the May-June spring flood season for 10 years, and distributed to an e-mail list that grew to over 300 subscribers. This provides near real-time tracking of water levels and breakup using on-line gauges (Environment Canada), daily MODIS satellite imagery (NASA), Landsat imagery (USGS) and intermittent radar imagery (various sources). In earlier years, information was also supplied from field programs operating in the delta during breakup, but changing priorities and funding have reduced the number of outside researchers present during these critical weeks. Meanwhile the number of local contributors has grown, providing observations and photographs to share with the local, regional and global readership. In this way the newsletter evolved into a two-way communication tool and community portal. The newsletter is a chronicle of each breakup season and a key resource for territorial and municipal managers, subsistence organizations, and emergency response agencies, with routine requests for specific imagery in areas of concern. With the completion of 10 years under the present model, we are exploring

  11. Spatial variations in geochemical characteristics of the modern Mackenzie Delta sedimentary system

    NASA Astrophysics Data System (ADS)

    Vonk, Jorien E.; Giosan, Liviu; Blusztajn, Jerzy; Montlucon, Daniel; Graf Pannatier, Elisabeth; McIntyre, Cameron; Wacker, Lukas; Macdonald, Robie W.; Yunker, Mark B.; Eglinton, Timothy I.

    2015-12-01

    The Mackenzie River in Canada is by far the largest riverine source of sediment and organic carbon (OC) to the Arctic Ocean. Therefore the transport, degradation and burial of OC along the land-to-ocean continuum for this riverine system is important to study both regionally and as a dominant representative of Arctic rivers. Here, we apply sedimentological (grain size, mineral surface area), and organic and inorganic geochemical techniques (%OC, δ13C-OC and Δ14C-OC, 143Nd/144Nd, δ2H and δ18O, major and trace elements) on particulate, bank, channel and lake surface sediments from the Mackenzie Delta, as well as on surface sediments from the Mackenzie shelf in the Beaufort Sea. Our data show a hydrodynamic sorting effect resulting in the accumulation of finer-grained sediments in lake and shelf deposits. A general decrease in organic carbon (OC) to mineral surface area ratios from river-to-sea furthermore suggests a loss of mineral-bound terrestrial OC during transport through the delta and deposition on the shelf. The net isotopic value of the terrestrial OC that is lost en route, derived from relationships between δ13C, OC and surface area, is -28.5‰ for δ13C and -417‰ for Δ14C. We calculated that OC burial efficiencies are around 55%, which are higher (∼20%) than other large river systems such as the Amazon. Old sedimentary OC ages, up to 12 14C-ky, suggest the delivery of both a petrogenic OC source (with an estimated contribution of 19 ± 9%) as well as a pre-aged terrestrial OC source. We calculated the 14C-age of this pre-aged, biogenic, component to be about 6100 yrs, or -501‰, which illustrates that terrestrial OC in the watershed can reside for millennia in soils before being released into the river. Surface sediments in lakes across the delta (n = 20) showed large variability in %OC (0.92-5.7%) and δ13C (-30.7‰ to -23.5‰). High-closure lakes, flooding only at exceptionally high water levels, hold high sedimentary OC contents (>2.5%) and

  12. Functional Carbon Processing and Its Linkage to Hydrology in Lakes of the Mackenzie River Delta

    NASA Astrophysics Data System (ADS)

    Lesack, L.; Tank, S. E.; Gareis, J.; Chateauvert, C. A.; Squires, M.; Marsh, P.

    2011-12-01

    The circumpolar arctic contains a number of large river deltas that are lake-rich because of thermokarst effects. The Mackenzie Delta is the second largest, containing 45,000 lakes within a floodplain area 1/3rd the size of Switzerland. A 20-year case study has placed the biogeochemistry of these lakes into context via analysis of 40 years of water level records, river-to-lake connectivities, and estimates of annual river-water renewal. The lakes collectively represent gradients from turbid waters to transparent, high dissolved-nutrients to low, low total dissolved organic matter (DOM) to high, high chromophoric-DOM (CDOM) to low, high inorganic content of lake sediments to high organic sediment, and low under-water ultraviolet-irradiance to higher irradiances. Super imposed on these are biotic community production gradients respectively ranging from low production of aquatic bacteria to high, low macrophytes to high, low epiphyton to high, high phytoplankton and epipelon at intermediate flooding-frequencies, low small-bodied zooplankton to high large-bodied, high fish to no fish, and moderate aquatic birds to high. All the above correspond with a gradient of lake flooding regimes with average river-to-lake connection times ranging from >150 days per year in the lowest elevation lakes maintaining near continuous connection with the river over the open-water period to <4.5 days per year in the highest elevation lakes with long and variable disconnection periods from the river. Thermokarst lakes and lake-chain systems represent special cases where lake behaviors may depart from patterns otherwise strongly linked to river-to-lake connection times. Based on work in this system thus far, we propose a new conceptual model of overall carbon processing based on functional groups of organisms and abiotic processes that govern the overall balance between recycling of carbon to the atmosphere as CO2 or CH4, or the accumulation and storage of carbon in lake biomasses, and

  13. Abundance and patterns of transparent exopolymer particles (TEP) in Arctic floodplain lakes of the Mackenzie River Delta

    NASA Astrophysics Data System (ADS)

    Chateauvert, C. Adam; Lesack, Lance F. W.; Bothwell, Max L.

    2012-12-01

    The Mackenzie River Delta is a lake-rich arctic floodplain that receives high inputs of dissolved organic matter (DOM) and suspended particulates from allochthonous and autochthonous sources, and may transfer carbon from dissolved to particulate phase via in situ formation of transparent exopolymer particles (TEP). TEP provides food for grazers, surfaces for bacteria, and increased potential for aggregation and sedimentation of organic matter. During open water 2006, we tracked TEP abundances in three Delta lakes representing gradients that include declining river-to-lake connection times, increasing levels of dissolved organic carbon (DOC), and declining chromophoric-DOM (CDOM). Unexpectedly, TEP abundances were highest immediately after the flood, when autochthonous autotrophic production was at a seasonal low and CDOM a seasonal high. Moreover, the lake with the strongest riverine influence and lowest levels of autochthonous autotrophic production had the highest mean TEP-carbon (TEP-C) concentrations among the lakes. The mean proportion of particulate organic carbon (POC) represented by TEP-C increased with increasing river connection time, and appears to represent a substantial proportion of POC in Mackenzie Delta Lakes. Unexpectedly, the TEP gradient was most strongly related to CDOM (river water source) rather than overall DOC. Variations in CDOM accounted for 53% of TEP-C variation among the lakes, indicating allochthonous matter was the most important source of TEP. DOC release from in situ macrophytes during periods of high photosynthesis may contribute to TEP formation in the lake with lowest riverine influence, but pH levels >9.5 driven by the high photosynthetic rates complicate the interpretation of results from this lake.

  14. Spring-Summer Temperatures Since AD 1780 Reconstructed from Stable Oxygen Isotope Ratios in White Spruce Tree-Rings from the Mackenzie Delta, Northwestern Canada

    NASA Technical Reports Server (NTRS)

    Porter, Trevor J.; Pisaric, Michael F. J.; Field, Robert D.; Kokelj, Steven V.; Edwards, Thomas W. D.; deMontigny, Peter; Healy, Richard; LeGrande, Allegra N.

    2013-01-01

    High-latitude delta(exp 18)O archives deriving from meteoric water (e.g., tree-rings and ice-cores) can provide valuable information on past temperature variability, but stationarity of temperature signals in these archives depends on the stability of moisture source/trajectory and precipitation seasonality, both of which can be affected by atmospheric circulation changes. A tree-ring delta(exp 18)O record (AD 1780-2003) from the Mackenzie Delta is evaluated as a temperature proxy based on linear regression diagnostics. The primary source of moisture for this region is the North Pacific and, thus, North Pacific atmospheric circulation variability could potentially affect the tree-ring delta(exp 18)O-temperature signal. Over the instrumental period (AD 1892-2003), tree-ring delta(exp 18)O explained 29% of interannual variability in April-July minimum temperatures, and the explained variability increases substantially at lower-frequencies. A split-period calibration/verification analysis found the delta(exp 18)O-temperature relation was time-stable, which supported a temperature reconstruction back to AD 1780. The stability of the delta(exp 18)O-temperature signal indirectly implies the study region is insensitive to North Pacific circulation effects, since North Pacific circulation was not constant over the calibration period. Simulations from the NASA-GISS ModelE isotope-enabled general circulation model confirm that meteoric delta(exp 18)O and precipitation seasonality in the study region are likely insensitive to North Pacific circulation effects, highlighting the paleoclimatic value of tree-ring and possibly other delta(exp 18)O records from this region. Our delta(exp 18)O-based temperature reconstruction is the first of its kind in northwestern North America, and one of few worldwide, and provides a long-term context for evaluating recent climate warming in the Mackenzie Delta region.

  15. Numerical studies of gas production from several CH4 hydrate zones at the Mallik site, Mackenzie Delta, Canada

    USGS Publications Warehouse

    Moridis, G.J.; Collett, T.S.; Dallimore, S.R.; Satoh, T.; Hancock, S.; Weatherill, B.

    2004-01-01

    The Mallik site represents an onshore permafrost-associated gas hydrate accumulation in the Mackenzie Delta, Northwest Territories, Canada. A gas hydrate research well was drilled at the site in 1998. The objective of this study is the analysis of various gas production scenarios from five methane hydrate-bearing zones at the Mallik site. In Zone #1, numerical simulations using the EOSHYDR2 model indicated that gas production from hydrates at the Mallik site was possible by depressurizing a thin free gas zone at the base of the hydrate stability field. Horizontal wells appeared to have a slight advantage over vertical wells, while multiwell systems involving a combination of depressurization and thermal stimulation offered superior performance, especially when a hot noncondensible gas was injected. Zone #2, which involved a gas hydrate layer with an underlying aquifer, could yield significant amounts of gas originating entirely from gas hydrates, the volumes of which increased with the production rate. However, large amounts of water were also produced. Zones #3, #4 and #5 were lithologically isolated gas hydrate-bearing deposits with no underlying zones of mobile gas or water. In these zones, thermal stimulation by circulating hot water in the well was used to induce dissociation. Sensitivity studies indicated that the methane release from the hydrate accumulations increased with the gas hydrate saturation, the initial formation temperature, the temperature of the circulating water in the well, and the formation thermal conductivity. Methane production appears to be less sensitive to the specific heat of the rock and of the hydrate, and to the permeability of the formation. ?? 2004 Published by Elsevier B.V.

  16. Response to Mackenzie

    ERIC Educational Resources Information Center

    Peers, Chris

    2014-01-01

    Chris Peers begins his response to Jim Mackenzie's article, "Peers on Socrates and Plato" by asking "What is the 'masculine imaginary?'" Peers defines the term "imaginary" as it is applied in his article, "Freud, Plato and Irigaray: A Morpho-Logic of Teaching and Learning" (2012) and draws…

  17. Interactions of polychlorinated biphenyls and organochlorine pesticides with sedimentary organic matter of retrogressive thaw slump-affected lakes in the tundra uplands adjacent to the Mackenzie Delta, NT, Canada

    NASA Astrophysics Data System (ADS)

    Eickmeyer, David C.; Kimpe, Linda E.; Kokelj, Steve V.; Pisaric, Michael F. J.; Smol, John P.; Sanei, Hamed; Thienpont, Joshua R.; Blais, Jules M.

    2016-02-01

    Using a comparative spatial analysis of sediment cores from eight lakes in tundra uplands adjacent to the Mackenzie Delta, NT, we examined how the presence of retrogressive thaw slumps on lake shores affected persistent organic pollutant (POPs, including polychlorinated biphenyls and organochlorine pesticides) accumulation in lake sediments. Sediments of slump-affected lakes contained higher total organic carbon (TOC)-normalized POP concentrations than nearby reference lakes that were unaffected by thaw slumps. Mean focus-corrected inorganic sedimentation rates were positively related to TOC-normalized contaminant concentrations, explaining 58-94% of the variation in POP concentrations in sediment, suggesting that reduced organic carbon in slump-affected lake water results in higher concentrations of POPs on sedimentary organic matter. This explanation was corroborated by an inverse relationship between sedimentary POP concentrations and TOC content of the lake water. Inferred chlorophyll a, S2, and S3 carbon fluxes to sediment were not significantly correlated to POP fluxes. Higher POP concentrations observed in sediment of slump-affected lakes are best explained by simple solvent switching processes of hydrophobic organic contaminants onto a smaller pool of available organic carbon when compared to neighboring lakes unaffected by thaw slump development.

  18. Towards a Cross-Cultural Program in the N.W.T.

    ERIC Educational Resources Information Center

    McPherson, Norm

    Indian education programs in Canadian Northwest Territories (NWT) are based on the philosophy of communication, local involvement, relevancy. To implement these, the NWT Education Department has developed made-in-the-NWT curriculum handbooks -- A Curriculum Guide for K-6 and Learning in the Middle Years. In the NWT's 62 schools, there are over 100…

  19. Against "Ressentiment": Response to Mackenzie

    ERIC Educational Resources Information Center

    Dahlbeck, Johan

    2016-01-01

    Johan Dahlbeck works as senior lecturer at Malmo University. His research interest is in the philosophy of education, focusing especially on ethics and the pedagogical implications of Spinoza's philosophy. In this article, he responds to Jim Mackenzie's "Dahlbeck and Pure Ontology" (EJ1105980), which was written in reply to his…

  20. Effects of Mackenzie River Discharge and Bathymetry on Sea Ice in the Beaufort Sea

    NASA Technical Reports Server (NTRS)

    Nghiem, S. V.; Hall, D. K.; Rigor, I. G; Li, P.; Neumann, G.

    2014-01-01

    Mackenzie River discharge and bathymetry effects on sea ice in the Beaufort Sea are examined in 2012 when Arctic sea ice extent hit a record low. Satellite-derived sea surface temperature revealed warmer waters closer to river mouths. By 5 July 2012, Mackenzie warm waters occupied most of an open water area about 316,000 sq km. Surface temperature in a common open water area increased by 6.5 C between 14 June and 5 July 2012, before and after the river waters broke through a recurrent landfast ice barrier formed over the shallow seafloor offshore the Mackenzie Delta. In 2012, melting by warm river waters was especially effective when the strong Beaufort Gyre fragmented sea ice into unconsolidated floes. The Mackenzie and other large rivers can transport an enormous amount of heat across immense continental watersheds into the Arctic Ocean, constituting a stark contrast to the Antarctic that has no such rivers to affect sea ice.

  1. MODFLOW-NWT, A Newton formulation for MODFLOW-2005

    USGS Publications Warehouse

    Niswonger, Richard G.; Panday, Sorab; Ibaraki, Motomu

    2011-01-01

    This report documents a Newton formulation of MODFLOW-2005, called MODFLOW-NWT. MODFLOW-NWT is a standalone program that is intended for solving problems involving drying and rewetting nonlinearities of the unconfined groundwater-flow equation. MODFLOW-NWT must be used with the Upstream-Weighting (UPW) Package for calculating intercell conductances in a different manner than is done in the Block-Centered Flow (BCF), Layer Property Flow (LPF), or Hydrogeologic-Unit Flow (HUF; Anderman and Hill, 2000) Packages. The UPW Package treats nonlinearities of cell drying and rewetting by use of a continuous function of groundwater head, rather than the discrete approach of drying and rewetting that is used by the BCF, LPF, and HUF Packages. This further enables application of the Newton formulation for unconfined groundwater-flow problems because conductance derivatives required by the Newton method are smooth over the full range of head for a model cell. The NWT linearization approach generates an asymmetric matrix, which is different from the standard MODFLOW formulation that generates a symmetric matrix. Because all linear solvers presently available for use with MODFLOW-2005 solve only symmetric matrices, MODFLOW-NWT includes two previously developed asymmetric matrix-solver options. The matrix-solver options include a generalized-minimum-residual (GMRES) Solver and an Orthomin / stabilized conjugate-gradient (CGSTAB) Solver. The GMRES Solver is documented in a previously published report, such that only a brief description and input instructions are provided in this report. However, the CGSTAB Solver (called XMD) is documented in this report. Flow-property input for the UPW Package is designed based on the LPF Package and material-property input is identical to that for the LPF Package except that the rewetting and vertical-conductance correction options of the LPF Package are not available with the UPW Package. Input files constructed for the LPF Package can be used

  2. Mercury export to the Arctic Ocean from the Mackenzie River, Canada.

    PubMed

    Emmerton, Craig A; Graydon, Jennifer A; Gareis, Jolie A L; St Louis, Vincent L; Lesack, Lance F W; Banack, Janelle K A; Hicks, Faye; Nafziger, Jennifer

    2013-07-16

    Circumpolar rivers, including the Mackenzie River in Canada, are sources of the contaminant mercury (Hg) to the Arctic Ocean, but few Hg export studies exist for these rivers. During the 2007-2010 freshet and open water seasons, we collected river water upstream and downstream of the Mackenzie River delta to quantify total mercury (THg) and methylmercury (MeHg) concentrations and export. Upstream of the delta, flow-weighted mean concentrations of bulk THg and MeHg were 14.6 ± 6.2 ng L(-1) and 0.081 ± 0.045 ng L(-1), respectively. Only 11-13% and 44-51% of bulk THg and MeHg export was in the dissolved form. Using concentration-discharge relationships, we calculated bulk THg and MeHg export into the delta of 2300-4200 kg yr(-1) and 15-23 kg yr(-1) over the course of the study. Discharge is not presently known in channels exiting the delta, so we assessed differences in river Hg concentrations upstream and downstream of the delta to estimate its influence on Hg export to the ocean. Bulk THg and MeHg concentrations decreased 19% and 11% through the delta, likely because of particle settling and other processes in the floodplain. These results suggest that northern deltas may be important accumulators of river Hg in their floodplains before export to the Arctic Ocean.

  3. Sources and circulation of water and arsenic in the Giant Mine, Yellowknife, NWT, Canada.

    PubMed

    Clark, Ian D; Raven, Kenneth G

    2004-06-01

    Recovery of gold from arsenopyrite-hosted ore in the Giant Mine camp, Yellowknife, NWT, Canada, has left a legacy of arsenic contamination that poses challenges for mine closure planning. Seepage from underground chambers storing some 237,000 tonnes of arsenic trioxide dust, has As concentrations exceeding 4000 ppm. Other potential sources and sinks of As also exist. Sources and movement of water and arsenic are traced using the isotopes of water and sulphate. Mine waters (16 ppm As; AsV/AsIII approximately 150) are a mixture of two principal water sources--locally recharged, low As groundwaters (0.5 ppm As) and Great Slave Lake (GSL; 0.004 ppm As) water, formerly used in ore processing and discharged to the northwest tailings impoundment (NWTP). Mass balance with delta18O shows that recirculation of NWTP water to the underground through faults and unsealed drillholes contributes about 60% of the mine water. Sulphate serves to trace direct infiltration to the As2O3 chambers. Sulphate in local, low As groundwaters (0.3-0.6 ppm As; delta34SSO4 approximately 4% and delta18OSO4 approximately -10%) originates from low-temperature aqueous oxidation of sulphide-rich waste rock. The high As waters gain a component of 18O-enriched sulphate derived from roaster gases (delta18OSO4) = + 3.5%), consistent with their arsenic source from the As2O3 chambers. High arsenic in NWTP water (approximately 8 ppm As; delta18OSO4 = -2%) derived from mine water, is attenuated to close to 1 ppm during infiltration back to the underground, probably by oxidation and sorption by ferrihydrite.

  4. DELTAE

    SciTech Connect

    Ward, W.C. )

    1993-11-01

    In thermoacoustic engines and refrigerators, and in many simple acoustic systems, a one dimensional wave equation determines the spatial dependence of the acoustic pressure and velocity. DELTAE numerically integrates such wave equations in the acoustic approximation, in gases or liquids, in user-defined geometries. Boundary conditions can include conventional acoustic boundary conditions of geometry and impedance, as well as temperature and thermal power in thermoacoustic systems. DELTAE can be used easily for apparatus ranging from simple duct networks and resonators to thermoacoustic engines refrigerators and combinations thereof. It can predict how a given apparatus will perform, or can allow the user to design an apparatus to achieve desired performance. DELTAE views systems as a series of segments; twenty segment types are supported. The purely acoustic segments include ducts and cones, and lumped impedances including compliances, series impedances, and endcaps. Electroacoustics tranducer segments can be defined using either frequency-independent coefficients or the conventional parameters of loudspeaker-style drivers: mass, spring constant, magnetic field strength, etc. Tranducers can be current driven, voltage driven, or connected to an electrical load impedance. Thermoacoustic segment geometries include parallel plates, circular and rectangular pores, and pin arrays. Side branches can be defined with fixed impedances, frequency-dependent radiation impedances, or as an auxiliary series of segments of any types. The user can select working fluids from among air, helium, neon, argon, hydrogen, deuterium, carbon dioxide, nitrogen, helium-argon mixtures, helium-xenon mixtures, liquid sodium, and eutectic sodium-potassium. Additional fluids and solids can be defined by the user.

  5. Offshore Beaufort-Mackenzie basin and Amauligak oil discovery

    SciTech Connect

    Sharpe, R.J.; Gurba, G.J.; Sleumer, B.H.G.

    1988-01-01

    A variety of complex structural styles and depositional environments host hydrocarbon accumulations in the offshore Beaufort-Mackenzie basin. At present, only one of these, the Amauligak field, appears large enough to serve as a lead project to spur commercial development of the area. All offshore Beaufort discoveries to date occur in sandstones ranging from Paleocene to Oligocene in age. All occur in deltaic or delta-derived sediments ranging from delta-plain deposits to submarine fan/turbidites. In the western Beaufort, sediments are deformed into a series of linear diapiric features interpreted to be thrusted anticlines, possible associated with strike-slip faulting. Similarly, the Tarsiut area immediately to the east is dominated by diapiric anticlines crosscut by a major east-west-trending fault, also possibly a strike-slip fault. In contrast, the central and eastern portions of the offshore Beaufort, where Amauligak is located, are characterized by growth faulting in the sand-rich Oligocene depocenter. To the north, in a basinward direction, unfaulted diapiric anticlines are draped by submarine fans. These structures may in part be related to the gravitational faults to the south. The Amauligak field is located in the growth fault province. It is contained with a large, south-dipping, simple fault-bounded structure in which hydrocarbons are trapped against the north-bounding listric fault. Sediments penetrated at Amauligak include more than 1,500 m of interbedded Oligocene sandstones and shales, the sandstones representing primarily delta-front deposits. Distinctive shale markers are the probable result of the switching of major deltaic lobes.

  6. Morphology and development of ice patches in NWT, Canada

    NASA Astrophysics Data System (ADS)

    Meulendyk, Thomas

    Permanent ice patches in the western Canadian Subarctic have been recently identified as sources of cryogenically preserved artifacts and biological specimens. The formation, composition and constancy of these ice patches have yet to be studied. As part of the NWT Ice Patch Study, ground-penetrating radar (GPR) and ice coring were used to examine the stratigraphy and internal structure of two ice patches. Results show the patches are composed of a core of staggered, distinct units, up to several meters thick, covered by a blanket of firn and snow. The interfaces between the layers of ice are often demarcated by thin sections of frozen caribou dung and fine sediment. A developmental model created using GPR data and radiocarbon dates (from dung extracted from ice cores) has revealed a long history for these perennial patches (up to 4400 years BP). Ice patch growth is discontinuous and occurs intermittently. Extensive time gaps exist between the units of ice indicating that summers of catastrophic melt can interrupt extended periods of net accumulation. The results of this work not only display the character of ice patch development, but also indicate the palaeoenvironmental and palaeoclimatic significance of the ice patches.

  7. Low-Altitude and Land-Based Infrared Thermography to Identify Types of Groundwater Discharge in NWT Streams

    NASA Astrophysics Data System (ADS)

    Conant, B.; Mochnacz, N. J.

    2009-05-01

    In tributaries of the Mackenzie River in the Northwest Territories (NWT), Canada, groundwater discharge provides critical fish habitat for Dolly Varden and bull trout populations by maintaining base flows, creating thermal refugia in winter, and providing stable riverbed temperatures for spawning. Where temperature contrasts exist between surface water and groundwater, infrared thermography can use heat as a tracer to locate groundwater discharge areas. Thermal images acquired from satellites and high altitude airplanes tend to be expensive, lack the resolution necessary to identify small discharge locations, and do not allow real time decisions to investigate and ground truth identified temperature anomalies. Therefore, a system was developed using a handheld FLIR ThermaCam P25 infrared camera, visual video camera, infrared video capture system, and GPS in a low flying helicopter and on the ground. The advantage of the system was its ability to inexpensively and efficiently characterize several kilometer long reaches of river and identify springs and seeps on a sub-meter scale and in real time. The different types of groundwater discharge that can occur in these streams include: deep geothermally heated groundwater; shallow groundwater; and active zone water, but differentiating them can be difficult because observed thermal anomalies can be non-unique functions of the initial groundwater temperature, magnitude of discharge, air and surface water temperatures, and temporal variations. Work performed in March and September easily detected spring and seeps of deep groundwater (8 to 13 ° C) at Smith Creek, Gibson Creek, Gayna River, and Little Fish Creek. Shallow groundwater discharge was detected (1 to 3 ° C) at White Sand Creek, Canyon Creek, and Fish Creek, but was more difficult to identify. Subtle variations from surrounding temperatures (<1 ° C) at some sites suggested seeps from the hyporheic zone or possibly the active zone. The limitations of infrared

  8. Assessing the Intellectual Ability of Indian and Metis Pupils at Ft. Simpson, N.W.T.

    ERIC Educational Resources Information Center

    MacArthur, R.S.

    The study assessed the general intellectual ability of Indian and Metis pupils of the Northwest Territory (N.W.T.), Canada. While minimizing cultural bias, an attempt was made to identify economical tests for this cultural group which would demonstrate (1) minimal loading on verbal and other culture-bound factors, (2) moderate relationship to…

  9. Introduction of the 2007-2008 JOGMEC/NRCan/Aurora Mallik Gas Hydrate Production Research Program, NWT, Canada

    NASA Astrophysics Data System (ADS)

    Yamamoto, K.; Dallimore, S. R.; Numasawa, M.; Yasuda, M.; Fujii, T.; Fujii, K.; Wright, J.; Nixon, F.

    2007-12-01

    Japan Oil, Gas and Metals National Corporation (JOGMEC) and Natural Resource Canada (NRCan) have embarked on a new research program to study the production potential of gas hydrates. The program is being carried out at the Mallik gas hydrate field in the Mackenzie Delta, a location where two previous scientific investigations have been carried in 1998 and 2002. In the 2002 program that was undertaken by seven partners from five countries, 468m3 of gas flow was measured during 124 hours of thermal stimulation using hot warm fluid. Small-scale pressure drawdown tests were also carried out using Schlumberger's Modular Dynamics Tester (MDT) wireline tool, gas flow was observed and the inferred formation permeabilities suggested the possible effectiveness of the simple depressurization method. While the testing undertaken in 2002 can be cited as the first well constrained gas production from a gas hydrate deposit, the results fell short of that required to fully calibrate reservoir simulation models or indeed establish the technical viability of long term production from gas hydrates. The objectives of the current JOGMEC/NRCan/Aurora Mallik production research program are to undertake longer term production testing to further constrain the scientific unknowns and to demonstrate the technical feasibility of sustained gas hydrate production using the depressurization method. A key priority is to accurately measure water and gas production using state-of-art production technologies. The primary production test well was established during the 2007 field season with the re-entry and deepening of JAPEX/JNOC/GSC Mallik 2L-38 well, originally drilled in 1998. Production testing was carried out in April of 2007 under a relatively low drawdown pressure condition. Flow of methane gas was measured from a 12m perforated interval of gas-hydrate-saturated sands from 1093 to 1105m. The results establish the potential of the depressurization method and provide a basis for future

  10. Monitoring ice break-up on the Mackenzie River using MODIS data

    NASA Astrophysics Data System (ADS)

    Muhammad, P.; Duguay, C.; Kang, K.-K.

    2016-03-01

    The aim of this study was to develop an approach for estimating ice break-up dates on the Mackenzie River (MR) using more than a decade of MODIS Level 3 500 m snow products (MOD/MYD10A1), complemented with 250 m Level 1B radiance products (MOD/MYD02QKM) from the Terra and Aqua satellite platforms. The analysis showed break-up began on average between days of year (DOYs) 115 and 125 and ended between DOYs 145 and 155 over 13 ice seasons (2001-2013), resulting in an average melt duration of ca. 30-40 days. Thermal processes were more important in driving ice break-up south of the MR confluence with the Liard River, while dynamically driven break-up was more important north of the Liard. A comparison of the timing of ice disappearance with snow disappearance from surrounding land areas of the MR with MODIS Level 3 snow products showed varying relationships along the river. Ice-off and snow-off timing were in sync north of the MR-Liard River confluence and over sections of the MR before it enters the Mackenzie Delta, but ice disappeared much later than snow on land in regions where thermal ice break-up processes dominated. MODIS observations revealed that channel morphology is a more important control of ice break-up patterns than previously believed with ice runs on the MR strongly influenced by channel morphology (islands and bars, confluences and channel constriction). Ice velocity estimates from feature tracking were able to be made in 2008 and 2010 and yielded 3-4-day average ice velocities of 1.21 and 1.84 m s-1 respectively, which is in agreement with estimates from previous studies. These preliminary results confirm the utility of daily MODIS data for monitoring ice break-up processes along the Mackenzie River. The addition of optical and synthetic aperture radar data from recent and upcoming satellite missions (e.g. Sentinel-1/2/3 and RADARSAT Constellation) would improve the monitoring of ice break-up in narrower sections of the MR.

  11. Remote sensing the dynamics of suspended particles in the Mackenzie River plume (Canadian Arctic Ocean)

    NASA Astrophysics Data System (ADS)

    Doxaran, D.; Ehn, J.; Bélanger, S.; Matsuoka, A.; Hooker, S.; Babin, M.

    2012-04-01

    Climate change significantly impacts Arctic shelf regions in terms of air temperature, ultraviolet radiation, melting of sea ice, precipitation, thawing of permafrost and coastal erosion. A direct consequence is an increase in Arctic river discharge with an expectation of increased delivery of organic carbon sequestered in high-latitute soils since the last glacial maximum. Monitoring the fluxes and fate of this terrigenous organic carbon is problematic in such sparsely populated regions unless remote sensing techniques can be developed to an operational stage. The main objective of this study is to develop an ocean colour algorithm to operationally monitor dynamics of suspended particulate matter (SPM) on the Mackenzie River continental shelf (Canadian Arctic Ocean) using satellite imagery. The water optical properties are documented across the study area and related to concentrations of SPM and particulate organic carbon (POC). Robust SPM and POC:SPM proxies are identified, such as the light backscattering and attenuation coefficients, and relationships are established between these optical and biogeochemical parameters. Following a semi-analytical approach, a regional SPM quantification relationship is obtained for the inversion of the water reflectance signal into SPM concentration. This relationship is validated based on independent field optical measurements. It is successfully applied to a selection of MODIS satellite data which allow estimating fluxes at the river mouth and monitoring the extension and dynamics of the Mackenzie River surface plume in 2009, 2010 and 2011. Good agreement is obtained with field observations representative of the whole water column in the river delta zone within which terrigenous SPM is mainly constrained (out of short periods of maximum river outflow). Most of the seaward export of SPM is observed to occur within the west side of the river mouth. Future work require the validation of the developed SPM regional algorithm based

  12. AmeriFlux US-NR1 Niwot Ridge Forest (LTER NWT1)

    DOE Data Explorer

    Blanken, Peter [University of Colorado

    2016-01-01

    This is the AmeriFlux version of the carbon flux data for the site US-NR1 Niwot Ridge Forest (LTER NWT1). Site Description - The Niwot Ridge AmeriFlux site is located in a subalpine forest ecosystem just below the Continental Divide near Nederland, CO. The site is located at 3050 m elevation, within 600m of the NOAA C1 long-term monitoring station, approximately 8 km east of the Continental Divide. The surrounding subalpine forest is ~97 years old and in a state of aggradation, having recovered from early twentieth century logging (Monson, et al. Global Change Biology (2002), 8 459-478).

  13. Optical Characterisation of Suspended Particles in the Mackenzie River Plume (Canadian Arctic Ocean) and Implications for Ocean Colour Remote Sensing

    NASA Technical Reports Server (NTRS)

    Doxaran, D.; Ehn, J.; Belanger, S.; Matsuoka, A.; Hooker, S.; Babin, M.

    2012-01-01

    Climate change significantly impacts Arctic shelf regions in terms of air temperature, ultraviolet radiation, melting of sea ice, precipitation, thawing of permafrost and coastal erosion. Direct consequences have been observed on the increasing Arctic river flow and a large amount of organic carbon sequestered in soils at high latitudes since the last glacial maximum can be expected to be delivered to the Arctic Ocean during the coming decade. Monitoring the fluxes and fate of this terrigenous organic carbon is problematic in such sparsely populated regions unless remote sensing techniques can be developed and proved to be operational. The main objective of this study is to develop an ocean colour algorithm to operationally monitor dynamics of suspended particulate matter (SPM) on the Mackenzie River continental shelf (Canadian Arctic Ocean) using satellite imagery. The water optical properties are documented across the study area and related to concentrations of SPM and particulate organic carbon (POC). Robust SPM and POC : SPM proxies are identified, such as the light backscattering and attenuation coefficients, and relationships are established between these optical and biogeochemical parameters. Following a semi-analytical approach, a regional SPM quantification relationship is obtained for the inversion of the water reflectance signal into SPM concentration. This relationship is reproduced based on independent field optical measurements. It is successfully applied to a selection of MODIS satellite data which allow estimating fluxes at the river mouth and monitoring the extension and dynamics of the Mackenzie River surface plume in 2009, 2010 and 2011. Good agreement is obtained with field observations representative of the whole water column in the river delta zone where terrigenous SPM is mainly constrained (out of short periods of maximum river outflow). Most of the seaward export of SPM is observed to occur within the west side of the river mouth. Future

  14. Optical characterisation of suspended particles in the Mackenzie River plume (Canadian Arctic Ocean) and implications for ocean colour remote sensing

    NASA Astrophysics Data System (ADS)

    Doxaran, D.; Ehn, J.; Bélanger, S.; Matsuoka, A.; Hooker, S.; Babin, M.

    2012-08-01

    Climate change significantly impacts Arctic shelf regions in terms of air temperature, ultraviolet radiation, melting of sea ice, precipitation, thawing of permafrost and coastal erosion. Direct consequences have been observed on the increasing Arctic river flow and a large amount of organic carbon sequestered in soils at high latitudes since the last glacial maximum can be expected to be delivered to the Arctic Ocean during the coming decade. Monitoring the fluxes and fate of this terrigenous organic carbon is problematic in such sparsely populated regions unless remote sensing techniques can be developed and proved to be operational. The main objective of this study is to develop an ocean colour algorithm to operationally monitor dynamics of suspended particulate matter (SPM) on the Mackenzie River continental shelf (Canadian Arctic Ocean) using satellite imagery. The water optical properties are documented across the study area and related to concentrations of SPM and particulate organic carbon (POC). Robust SPM and POC : SPM proxies are identified, such as the light backscattering and attenuation coefficients, and relationships are established between these optical and biogeochemical parameters. Following a semi-analytical approach, a regional SPM quantification relationship is obtained for the inversion of the water reflectance signal into SPM concentration. This relationship is reproduced based on independent field optical measurements. It is successfully applied to a selection of MODIS satellite data which allow estimating fluxes at the river mouth and monitoring the extension and dynamics of the Mackenzie River surface plume in 2009, 2010 and 2011. Good agreement is obtained with field observations representative of the whole water column in the river delta zone where terrigenous SPM is mainly constrained (out of short periods of maximum river outflow). Most of the seaward export of SPM is observed to occur within the west side of the river mouth. Future

  15. From Natural to Design River Deltas

    NASA Astrophysics Data System (ADS)

    Giosan, Liviu

    2016-04-01

    Productive and biologically diverse, deltaic lowlands attracted humans since prehistory and may have spurred the emergence of the first urban civilizations. Deltas continued to be an important nexus for economic development across the world and are currently home for over half a billion people. But recently, under the double whammy of sea level rise and inland sediment capture behind dams, they have become the most threatened coastal landscape. Here I will address several deceptively simple questions to sketch some unexpected answers using example deltas from across the world from the Arctic to the Tropics, from the Danube to the Indus, Mississippi to Godavari and Krishna, Mackenzie to Yukon. What is a river delta? What is natural and what is not in a river delta? Are the geological and human histories of a delta important for its current management? Is maintaining a delta the same to building a new one? Can we design better deltas than Nature? These answers help us see clearly that survival of deltas in the next century depends on human intervention and is neither assured nor simple to address or universally applicable. Empirical observations on the hydrology, geology, biology and biochemistry of deltas are significantly lagging behind modeling capabilities endangering the applicability of numerical-based reconstruction solutions and need to be ramped up significantly and rapidly across the world.

  16. A 50 % increase in the mass of terrestrial particles delivered by the Mackenzie River into the Beaufort Sea (Canadian Arctic Ocean) over the last 10 years

    NASA Astrophysics Data System (ADS)

    Doxaran, D.; Devred, E.; Babin, M.

    2015-06-01

    Global warming has a significant impact on the regional scale on the Arctic Ocean and surrounding coastal zones (i.e., Alaska, Canada, Greenland, Norway and Russia). The recent increase in air temperature has resulted in increased precipitation along the drainage basins of Arctic rivers. It has also directly impacted land and seawater temperatures with the consequence of melting permafrost and sea ice. An increase in freshwater discharge by main Arctic rivers has been clearly identified in time series of field observations. The freshwater discharge of the Mackenzie River has increased by 25% since 2003. This may have increased the mobilization and transport of various dissolved and particulate substances, including organic carbon, as well as their export to the ocean. The release from land to the ocean of such organic material, which has been sequestered in a frozen state since the Last Glacial Maximum, may significantly impact the Arctic Ocean carbon cycle as well as marine ecosystems. In this study we use 11 years of ocean color satellite data and field observations collected in 2009 to estimate the mass of terrestrial suspended solids and particulate organic carbon delivered by the Mackenzie River into the Beaufort Sea (Arctic Ocean). Our results show that during the summer period, the concentration of suspended solids at the river mouth, in the delta zone and in the river plume has increased by 46, 71 and 33%, respectively, since 2003. Combined with the variations observed in the freshwater discharge, this corresponds to a more than 50% increase in the particulate (terrestrial suspended particles and organic carbon) export from the Mackenzie River into the Beaufort Sea.

  17. A 50% increase in the amount of terrestrial particles delivered by the Mackenzie River into the Beaufort Sea (Canadian Arctic Ocean) over the last 10 years

    NASA Astrophysics Data System (ADS)

    Doxaran, D.; Devred, E.; Babin, M.

    2015-01-01

    Global warming has a significant impact at the regional scale on the Arctic Ocean and surrounding coastal zones (i.e., Alaska, Canada, Greenland, Norway and Russia). The recent increase in air temperature has resulted in increased precipitations along the drainage basins of Arctic Rivers. It has also directly impacted land and seawater temperatures with the consequence of melting the permafrost and sea-ice. An increase in freshwater discharge by main Arctic rivers has been clearly identified in time series of field observations. The freshwater discharge of the Mackenzie River has increased by 25% since 2003. This may have increased the mobilization and transport of various dissolved and particulate substances, including organic carbon, as well as their export to the ocean. The release from land to the ocean of such organic material, which was sequestered as frozen since the last glacial maximum, may significantly impact the Arctic Ocean carbon cycle as well as marine ecosystems. In this study we use 11 years of ocean-colour satellite data and field observations collected in 2009 to estimate the amount of terrestrial suspended solids and particulate organic carbon delivered by the Mackenzie River into the Beaufort Sea (Arctic Ocean). Our results show that during the summer period the concentration of suspended solids at the river mouth, in the delta zone and in the river plume has increased by 46, 71 and 33%, respectively, since 2003. Combined with the variations observed in the freshwater discharge, this corresponds to a more than 50% increase in the particulate (terrestrial suspended particles and organic carbon) export from the Mackenzie River into the Beaufort Sea.

  18. Microsomal enzyme activities in beluga whales from the Mackenzie River Delta, Northwest Territories, Canada

    SciTech Connect

    Lockhart, L.; Metner, D.; Muir, D.; Delorme, P.; Dahlke, L.

    1995-12-31

    On two occasions the authors have obtained samples of liver from freshly killed beluga whales harvested by Inuit hunters. The first samples were obtained from whales trapped in the Husky Lakes; with the onset of winter, ice restricted these whales to small breathing holes where they were taken by hunters. They were found to be starving, with body weights about 200 kg less than those expected for whales of their length. Liver mixed-function oxygenase activities, ethoxyresorufin-O-deethylase and aryl hydrocarbon hydroxylase, correlated closely with blubber residues of polychlorinated biphenyls. A second group of whales was taken in the summer hunt in Kugmallit Bay and showed no sign of starvation. The enzyme activities in these whales had weaker statistical relationships to PCB residues. These observations suggested that mobilization of blubber by the starving whales may have released PCBs to act pharmacologically. The authors could not test this hypothesis directly on whales, but an experiment was carried out on laboratory fish to try to examine it. Arctic char were given low dosages of PCB congener 126 and then maintained on diets of full normal ration, half-ration and quarter-ration over a period of 48 weeks, with sub-sampling at intervals. Fish receiving less than maintenance rations responded with decreases in body fat and increases in EROD activities. These laboratory results suggest that correlations between enzymatic activities and PCBs in the starving whales may indeed have been the result of the loss of blubber and concomitant release of PCBs.

  19. Alkane, terpene and polycyclic aromatic hydrocarbon geochemistry of the Mackenzie River and Mackenzie shelf: Riverine contributions to Beaufort Sea coastal sediment

    NASA Astrophysics Data System (ADS)

    Yunker, Mark B.; Macdonald, Robie W.; Cretney, Walter J.; Fowler, Brian R.; McLaughlin, Fiona A.

    1993-07-01

    To study the largest source of river sediment to the Arctic Ocean, we have collected suspended particulates from the Mackenzie River in all seasons and sediments from the Mackenzie shelf between the river mouth and the shelf edge. These samples have been analyzed for alkanes, triterpenes and polycyclic aromatic hydrocarbons (PAHs). We found that naturally occurring hydrocarbons predominate in the river and on the shelf. These hydrocarbons include biogenic alkanes and triterpenes with a higher plant/peat origin, diagenetic PAHs from peat and plant detritus, petrogenic alkanes, triterpenes and PAHs from oil seeps and/or bitumens and combustion PAHs that are likely relict in peat deposits. Because these components vary independently, the season is found to strongly influence the concentration and composition of hydrocarbons in the Mackenzie River. While essentially the same pattern of alkanes, diagenetic hopanes and alkyl PAHs is observed in all river and most shelf sediment samples, alkane and triterpene concentration variations are strongly linked to the relative amount of higher plant/peat material. Polycyclic aromatic hydrocarbon molecular-mass profiles also appear to be tied primarily to varying proportions of peat, with an additional petrogenic component which is most likely associated with lithic material mobilized by the Mackenzie River at freshet. Consistent with the general lack of alkyl PAHs in peat, the higher PAHs found in the river are probably derived from forest and tundra fires. A few anthropogenic/pyrogenic compounds are manifest only at the shelf edge, probably due to a weakening of the river influence. We take this observation of pyrogenic PAHs and the pronounced source differences between two sediment samples collected at the shelf edge as evidence of a transition from dominance by the Mackenzie River to the geochemistry prevalent in Arctic regions far removed from major rivers.

  20. Mackenzie igneous events, Canada: Middle Proterozoic hotspot magmatism associated with ocean opening

    NASA Astrophysics Data System (ADS)

    LeCheminant, A. N.; Heaman, L. M.

    1989-12-01

    U sbnd Pb ages have been obtained for the Muskox intrusion and the Mackenzie dyke swarm. The age of a pyroxenite from the layered series of the intrusion is 1270 ± 4Ma. Baddeleyite fractions from four widely-spaced Mackenzie diabases define a single discordia line with an upper intercept age of 1267 ± 2Ma. The dyke age of 1267 Ma provides a precise time-marker for much of the northwestern Canadian Shield. Mackenzie intrusive events were coeval with eruption of Coppermine River flood basalts in the Coppermine homocline. The short time-span, large volume and specific focus of Mackenzie igneous events suggest that magmatism occurred above a large hotspot caused by the presence of a mantle plume. We infer that magmatism was initiated when rifting breached a large domal uplift supported by the plume-generated hotspot. The uplift-subsidence record in the Coppermine homocline is predicted by numerical models for rifting above hot asthenospheric mantle leading to ocean opening. An array of five large gravity anomalies north of the homocline may outline a region of stretched continental crust extensively intruded by Mackenzie mafic igneous bodies.

  1. Behaviour of lithium and its isotopes during weathering in the Mackenzie Basin, Canada

    NASA Astrophysics Data System (ADS)

    Millot, Romain; Vigier, Nathalie; Gaillardet, Jérôme

    2010-07-01

    We report Li isotopic compositions, for river waters and suspended sediments, of about 40 rivers sampled within the Mackenzie River Basin in northwestern Canada. The aim of this study is to characterize the behaviour of Li and its isotopes during weathering at the scale of a large mixed lithology basin. The Mackenzie River waters display systematically heavier Li isotopic compositions relative to source rocks and suspended sediments. The range in δ 7Li is larger in dissolved load (from +9.3‰ to +29.0‰) compared to suspended sediments (from -1.7‰ to +3.2‰), which are not significantly different from δ 7Li values in bedrocks. Our study shows that dissolved Li is essentially derived from the weathering of silicates and that its isotopic composition in the dissolved load is inversely correlated with its relative mobility when compared to Na. The highest enrichment of 7Li in the dissolved load is reported when Li is not or poorly incorporated in secondary phases after its release into solution by mineral dissolution. This counterintuitive observation is interpreted by the mixing of water types derived from two different weathering regimes producing different Li isotopic compositions within the Mackenzie River Basin. The incipient weathering regime characterizing the Rocky Mountains and the Shield areas produces 7Li enrichment in the fluid phase that is most simply explained by the precipitation of oxyhydroxide phases fractionating Li isotopes. The second weathering regime is found in the lowland area and produces the lower δ 7Li waters (but still enriched in 7Li compared to bedrocks) and the most Li-depleted waters (compared to Na). Fractionation factors suggest that the incorporation of Li in clay minerals is the mechanism that explains the isotopic composition of the lowland rivers. The correlation of boron and lithium concentrations found in the dissolved load of the Mackenzie Rivers suggests that precipitation of clay minerals is favoured by the

  2. Re-Os isotopic study of the Muskox intrusion, NWT, Canada

    NASA Astrophysics Data System (ADS)

    Day, J.; Hulbert, L.; Pearson, G.; Nowell, G.

    2003-04-01

    The 1270±4Ma Muskox intrusion is one of the largest layered intrusions in the world and is the intrusive centre the giant Mackenzie-Coppermine-Muskox igneous event, widely attributed to the presence of a mantle plume beneath the north western Canadian Shield during the middle Proterozoic. We have made a detailed Re-Os isotope study of the Muskox intrusion with the aim of constraining the origin and potential triggers for precious metal mineralization in layered intrusions, assessing the role of magma recharge versus crustal assimilation and sulphide participation during mineralization. In the process of understanding these factors, direct inference can be made on the source characteristics of the reservoirs involved during magma genesis, and which feed major continental magmatism events. Re-Os isotopic analyses have been performed on 32 well characterised samples from drill core which samples the entire stratigraphy of the Muskox intrusion. Initial 187Os/188Os span a very restricted range for the ultramafic portion of the intrusion, with γOs +3 to +5.5 relative to chondrite. These values are not indicative of crustal assimilation. Os isotopic ratios also show significant shifts at platinum group element enriched horizons. Common Os concentrations show close correlation with major element indices whilst Re concentrations are less systematic and anomalously low in the ultramafic horizons, especially those which have suffered intense fluid alteration. Re-Os isotopic data will also be presented on the keel dyke feeder to the Muskox intrusion and the contemporaneous, voluminous Coppermine volcanics including an andesite glass flow.

  3. The Influence of Volcanological and Sedimentological Processes on Diamond Grade Distribution: Examples From the Ekati Diamond Mine, NWT, Canada

    NASA Astrophysics Data System (ADS)

    Porritt, L. A.; Cas, R. A.; Ailleres, L.; Oshust, P.

    2009-05-01

    The study of the diamond distribution within two kimberlite pipes, Fox and Koala, from the Ekati Diamond Mine, NWT, Canada, in conjunction with detailed facies models has shown several distinct relationships of deposit type and grade distribution. In both pipes the lithological facies represent grade units which can be distinguished from each other in terms of relative size and abundance of diamonds. Positive correlation of olivine grain size and abundance with diamond grade is seen, indicating that density sorting of fragmental kimberlites occurs both in pyroclastic and resedimented deposits. Though surface geological processes do not control the diamond potential of the erupting magma, they can be responsible for concentrating diamonds into economically significant proportions. A good understanding of the eruption, transport and depositional processes responsible for the individual lithological units and the diamond distribution within them is important for successful resource estimation and may lead to recognition of areas suitable for selective mining, making a marginal deposit economic.

  4. Nile Delta

    Atmospheric Science Data Center

    2013-04-15

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

  5. Mississippi Delta

    Atmospheric Science Data Center

    2014-05-15

    article title:  The Mississippi Delta     Left: True Color Image ... Imaging SpectroRadiometer (MISR) images of the Mississippi delta were acquired on April 26, 2000. The true color image displays the ...

  6. Volga Delta

    Atmospheric Science Data Center

    2013-04-17

    article title:  Volga Delta and the Caspian Sea     View ... appear reddish. A small cloud near the center of the delta separates into red, green, and blue components due to geometric parallax ... include several linear features located near the Volga Delta shoreline. These long, thin lines are artificially maintained shipping ...

  7. Tectonic Framework of the Beaufort-Mackenzie Margin, Canadian Arctic Ocean, from Integrated Deep Seismic and Potential-Field Studies

    NASA Astrophysics Data System (ADS)

    Helwig, J. A.; Bird, D. E.; Kumar, N.; Emmet, P. A.; Dinkelman, M.

    2012-12-01

    A five-year long, ION ArcticSPAN seismic survey program in the Canadian Beaufort Sea expands and elaborates the tectonic framework of the Canada Basin passive margin. The margin is clearly subdivided into three segments of different orientation and structure: 1) the overprinted Cordilleran-Beaufort Foldbelt segment trending west towards Alaska; 2) the transtensional Tuk segment trending northeast off the Tuktoyaktuk Peninsula; and 3) the extensional Banks segment trending north off Banks Island. From nearshore to 2500 m depth, over 20,000 km of 2D long-offset data were acquired and processed into 40 km deep PSDM profiles. The latest lines used special technology for shooting beneath first-year ice-covered areas, and 450 km of OBC data were acquired in the nearshore transition zone. From well control in the Mackenzie Delta area, a geological interpretation is extended into the late Jurassic to Recent passive margin stratigraphy as well as the varying underlying crust of both oceanic affinity, and Ellesmerian and Laurentian continental affinities. Major elements of a tectonic synthesis include: 1) deep profiles show the Tertiary detached Beaufort foldbelt overlies greatly extended continental and/or oceanic crust although the COB is obscured by the overprint; 2) oceanic crust with steep relief is found at the inferred junction of the extinct spreading center of the Canada Basin in the Mackenzie delta; 3) on the Tuk margin, thick Proterozoic and Paleozoic strata flanking the Laurentian craton are terminated at the COB by a transform fault system; and 4) architecture of the Banks segment includes late Jurassic rift structure, and a continent-ocean transition beneath the continental slope prism that includes gravitational folds down-dip of shallower extensional break-away faults and rollover folds in the Tertiary. Our tectonic framework is consistent with a rotational model for opening of the Canada Basin. The free air gravity field is dominated by a high

  8. Sir James Mackenzie: from auricular paralysis and nodal rhythm to auricular fibrillation.

    PubMed

    Lippi, Donatella; Mascia, Giuseppe; Padeletti, Luigi

    2011-09-01

    The aim of this paper is to underline the role of Sir James Mackenzie in stating that atrial fibrillation is a distinct and clinically important arrhythmia and that it is a common condition in patients with cardiac disease. Around 1900, a few clinical researchers were dealing with cardiac arrhythmias with the use of arterial and venous pulse tracings. Sir James Mackenzie, who has been one of the fathers of modern cardiology, introduced registration of the venous pulse at the bedside using the clinical polygraph he had invented. He applied the results of his experimental and clinical discoveries to the explanation of many kinds of arrhythmias before ECG introduction. In our paper, we have especially considered the three steps of his approach to atrial fibrillation, the first two developed in the pre-ECG era. The invention of an instrument of precision, the electrocardiograph, revolutionized the diagnosis of heart disease and catalyzed the formation of cardiology as a specialty. PMID:21476085

  9. Mackenzie's puzzle--the cornerstone of teaching and research in general practice.

    PubMed

    Murdoch, J C

    1997-10-01

    The new-found popularity of generalism as a political force has emphasized the need to clarify the essential philosophy that underpins its practice, teaching, and research. Drawing on the example of Sir James Mackenzie, the author seeks to clarify certain essential issues that need to be emphasized if we are to promote and develop general practice as a distinct academic discipline. Dissatisfaction, uncertainty about our role, and continuing contact with real people seems to be essential to continuing creativity.

  10. The Aoraki Mackenzie International Dark Sky Reserve and light pollution issues in New Zealand

    NASA Astrophysics Data System (ADS)

    Hearnshaw, John

    2015-08-01

    I will discuss the Aoraki Mackenzie International Dark Sky Reserve, recognized by IDA in 2012, and how the reserve is managed and promoted to the public to make them aware of light pollution issues and in order to promote star-gazing and astro-tourism. AMIDSR is the world's largest Dark Sky Reserve recognized by IDA and has gold tier status. We will have a Starlight festival in October to promote the Reserve to the public.

  11. Genetics, recruitment, and migration patterns of Arctic Cisco (Coregonus autumnalis) in the Colville River, Alaska and Mackenzie River, Canada

    USGS Publications Warehouse

    Zimmerman, Christian E.; Ramey, Andy M.; Turner, S.; Mueter, Franz J.; Murphy, S.; Nielsen, Jennifer L.

    2013-01-01

    Arctic cisco Coregonus autumnalis have a complex anadromous life history, many aspects of which remain poorly understood. Some life history traits of Arctic cisco from the Colville River, Alaska, and Mackenzie River basin, Canada, were investigated using molecular genetics, harvest data, and otolith microchemistry. The Mackenzie hypothesis, which suggests that Arctic cisco found in Alaskan waters originate from the Mackenzie River system, was tested using 11 microsatellite loci and a single mitochondrial DNA gene. No genetic differentiation was found among sample collections from the Colville River and the Mackenzie River system using molecular markers (P > 0.19 in all comparisons). Model-based clustering methods also supported genetic admixture between sample collections from the Colville River and Mackenzie River basin. A reanalysis of recruitment patterns to Alaska, which included data from recent warm periods and suspected changes in atmospheric circulation patterns, still finds that recruitment is correlated to wind conditions. Otolith microchemistry (Sr/Ca ratios) confirmed repeated, annual movements of Arctic cisco between low-salinity habitats in winter and marine waters in summer.

  12. Significant Li isotope fractionation in geochemically evolved rare element-bearing pegmatites from the Little Nahanni Pegmatite Group, NWT, Canada

    NASA Astrophysics Data System (ADS)

    Barnes, Elspeth M.; Weis, Dominique; Groat, Lee A.

    2012-02-01

    Lithium isotope signatures of whole rock pegmatite samples and mineral separates from the rare element-bearing Little Nahanni Pegmatite Group, NWT, and whole rock samples from nearby granitic intrusions were measured. Correlation of the Li isotopic values from the pegmatite dikes with whole rock trace element geochemistry, mineralogy and primary textural evidence reflect mechanisms of Li isotopic fractionation during pegmatite formation. The heavier δ 7Li signatures within the broad range measured from whole rock LNPG samples (- 0.94‰ to + 11.36‰) are related to the consolidation of the final ~ 15% melt fraction of a volatile-rich peraluminous magma in the late stages of magmatic fractionation. Rock-forming minerals (quartz, albite, spodumene and mica) display δ 7Li signatures that indicate consolidation of the dikes under variable, non-equilibrium conditions. Lithium isotope signatures of relatively cool, highly evolved peraluminous magmas reflect the build-up of fluxes (e.g., H 2O and F) and provide a qualitative assessment of the state of mineral/melt chemical equilibrium.

  13. The Large Lake Effect on Mackenzie River Flow: an Isotopic Perspective

    NASA Astrophysics Data System (ADS)

    Gibson, J. J.

    2004-05-01

    The Mackenzie Basin (1.7 million sq. km) incorporates a diverse range of geographic source regions, including eight of the fifteen ecoclimatic regions identified in Canada. The basin is mountainous in the west and relatively flat-lying in the east with strong north-south climatic gradients, and generally cold, dry climate conditions compared to other large river basins in the world. As a major contributor of freshwater discharge to the Arctic Ocean, the river is distinct due to the occurrence of several large lakes (Lake Athabasca, Great Slave Lake, Great Bear Lake) which act as flow, sedimentation, and biogeochemical regulators along its main drainage network. A detailed water sampling network was established in 2002 to support isotope hydrology studies in the basin by Environment Canada, as well as modelling efforts conducted in association with the Mackenzie GEWEX Study and the IAEA Coordinated Research Project on Rivers. Results from this survey reveal the complex evolution of the isotopic composition of river discharge from the headwaters of the Mackenzie River to the mouth, particularly the mixing of tributary inflows and the buffering effect of the large lakes. Spatially, the most depleted isotope signatures are observed for tributaries of the Western Cordillera, especially the Mackenzie Mountains, which are characterized by higher-altitude precipitation, greater snowfall, and higher runoff/precipitation ratios than other parts of the basin. In contrast, shield-dominated eastern areas and the central boreal-taiga plains tend to have enriched isotopic signatures reflecting lower altitude precipitation as well as significant contributions from evaporated lake and wetland sources. Here, rivers commonly traverse extensive string-of-lakes and bog-fen drainage networks. In addition, seasonality of the riverine isotopic signals is often pronounced, reflecting varying proportions of flow derived from snowmelt, groundwater, and surface waters during the ice

  14. Results of exploratory drilling at Point MacKenzie, Alaska, 1981

    USGS Publications Warehouse

    Patrick, Leslie

    1981-01-01

    The Matanuska-Susitna Borough anticipates industrial development near Point MacKenzie, Alaska. Because little hydrologic information is available for the area, the Borough contracted for the drilling of two test wells. It was found that: Both wells penetrated unconsolidated stratified clay, silt, sand, and gravel; each well penetrated a shallow unconfined and deeper confined aquifers; the water levels in the wells rise and fall with the tide; the chemical analyses indicate that the water quality meets the Alaska Drinking Water Standards, except for slightly high levels of manganese and pH; and the potential for saltwater intrusion should be evaluated as part of future studies. (USGS)

  15. Integrated regional assessment of global climatic change: lessons from the Mackenzie Basin Impact Study (MBIS)

    NASA Astrophysics Data System (ADS)

    Cohen, Stewart J.

    1996-04-01

    This paper outlines the potential role integrated regional assessments of global climatic change scenarios could play in building better links between science and related policy concerns. The concept is illustrated through description of an ongoing case study from Canada—the Mackenzie Basin Impact Study (MBIS). As part of the Government of Canada's Green Plan, the Global Warming Science Program includes a study of regional impacts of global warming scenarios in the Mackenzie Basin, located in northwestern Canada. The MBIS is a six-year program focussing on potential climate-induced changes in the land and water resource base, and the implications of four scenarios of global climatic change on land use and economic policies in this region. These policy issues include interjurisdictional water management, sustainability of native lifestyles, economic development opportunities (agriculture, forestry, tourism, etc.), sustainability of ecosystems and infrastructure maintenance. MBIS is due to be completed in 1997. MBIS represents an attempt to address regional impacts by incorporating a "family of integrators" into the study framework, and by directly involving stakeholders in planning and research activities. The experience in organizing and carrying out this project may provide some lessons for others interested in organizing regional or country studies.

  16. Derivation of Lake Areas and Elevations for the Mackenzie Basin Using Satellite Remote Sensing

    NASA Technical Reports Server (NTRS)

    Birkett, Charon; Kite, Geoff

    1997-01-01

    Modelling hydrological processes in large watersheds flowing to the Arctic ocean is one step towards larger-scale modelling of the global water and energy cycles. Models of the Mackenzie River Basin (Northern Canada) are currently available but omit explicit routing of river flows through the three main lakes - Athabasca, Great Slave Lake and Great Bear Lake (Kite et al, 1994). These lakes occupy an area of 65,000 sq km but little gauge information is available. The levels of the lakes are only measured at a few points on the circumferences and river flows are only measured downstream. The hydraulic relationships between level/discharge and level/area/volume are uncertain. It has been previously shown that satellite remote sensing can be utilised in providing measurements of both lake surface area using imaging techniques and lake level using radar altimetry (Birkett, 1994). Here, we explore the application of these techniques to derive the lake levels and areas for the Mackenzie Basin lakes.

  17. Sustained sulfide oxidation by physical erosion processes in the Mackenzie River basin: Climatic perspectives

    NASA Astrophysics Data System (ADS)

    Calmels, Damien; Gaillardet, Jérôme; Brenot, Agnès; France-Lanord, Christian

    2007-11-01

    The chemical weathering of rocks with sulfuric acid is usually not considered in reconstructions of the past evolution of the carbon cycle, although this reaction delivers cations and alkalinity to the ocean without involvement of atmospheric CO2. The contribution of sulfuric acid as a weathering agent is still poorly quantified; the identification of riverine sulfate sources is difficult. The use of δ34S and δ18O of dissolved sulfate allows us to demonstrate that most of the sulfate in surface waters of the Mackenzie River system, Canada, derives from pyrite oxidation (85% ± 5%) and not from sedimentary sulfate. The calculated flux of pyrite-derived sulfate is 0.13 × 1012 mol/yr, corresponding to 20%-27% of the estimated global budget. This result suggests that the modern global ocean delivery of sulfide-derived sulfate, and thus chemical weathering with sulfuric acid, may be significantly underestimated. A strong correlation between sulfide oxidation rates and mechanical erosion rates suggests that the exposure of fresh mineral surfaces is the rate-limiting factor of sulfide oxidation in the subbasins investigated. The chemical weathering budget of the Mackenzie River shows that more than half of the dissolved inorganic carbon discharged to the ocean is ancient sedimentary carbon from carbonate (62%) and not atmospheric carbon (38%). The subsequent carbonate precipitation in the ocean will thus release more CO2 in the atmosphere-ocean system than that consumed by continental weathering, typically on glacial-interglacial time scales.

  18. Commentary: Sir James Mackenzie (1853-1925): an ambiguous pioneer for research in primary care.

    PubMed

    Tudor Hart, Julian

    2012-12-01

    Sir James Mackenzie is generally accepted as the founder of research by general practitioners in Great Britain, studying their own patients where and how they actually live. His pioneering work on arrhythmias was a foundation for modern cardiology, consolidated by his pupil Thomas Lewis, Britain's first full-time clinical researcher for the Medical Research Council. Mackenzie became a dominant figure in public imagination, more widely celebrated than any later generalist. At the clinical research institute he founded at St Andrews in 1919, he hoped to set in train a permanent and growing body of longitudinal clinical research outside hospitals, by community generalists studying their own patients. This article tries to explain the failure of this project: how it influenced later research by general practitioners and others in primary care after creation of the National Health Service (NHS) in 1948 and its relevance today to primary care research policy. Such research is now becoming an urgent necessity, for the British National Health Service to survive as a public service and as a foundation for democratic development of biosciences.

  19. The brucellosis and tuberculosis status of wood bison in the Mackenzie Bison Sanctuary, Northwest Territories, Canada.

    PubMed Central

    Tessaro, S V; Gates, C C; Forbes, L B

    1993-01-01

    Postmortem examinations were done on 51 wood bison (Bison bison athabascae) killed as part of a multidisciplinary research project in the Mackenzie Bison Sanctuary, Northwest Territories, Canada, between 1986 and 1988. There was no gross, histological or bacteriological evidence of brucellosis or tuberculosis in these bison. Traumatic lesions were seen in one calf that had been attacked by wolves and a second calf that had been gored. Antibody titers to Brucella abortus were not found in sera from these 51 animals or an additional 112 wood bison that were chemically-immobilized or killed in the Sanctuary between 1986 and 1990. The combined prevalence of the diseases in the population could not have exceeded 5.95% for the necropsy survey to have missed finding at least one infected animal, and the prevalence of brucellosis in the population would have had to be less than 1.95% for the broader serological survey to have failed to find at least one reactor animal on the battery of tests. These results, and the cumulative epidemiological information on brucellosis and tuberculosis in bison, indicate that bovine brucellosis and tuberculosis are not enzootic in the wood bison population in and around the Mackenzie Bison Sanctuary, and suggest that the population is free of these diseases. However, this expanding population is at risk of contracting both diseases from the infected bison population in and around nearby Wood Buffalo National Park. PMID:8269360

  20. A crust-scale 3D structural model of the Beaufort-Mackenzie Basin (Arctic Canada)

    NASA Astrophysics Data System (ADS)

    Sippel, Judith; Scheck-Wenderoth, Magdalena; Lewerenz, Björn; Kroeger, Karsten Friedrich

    2013-04-01

    The Beaufort-Mackenzie Basin was initiated in the Early Jurassic as part of an Arctic rifted passive continental margin which soon after became overprinted by Cordilleran foreland tectonics. Decades of industrial exploration and scientific research in this petroliferous region have produced a wide spectrum of geological and geophysical data as well as geoscientific knowledge. We have integrated available grids of sedimentary horizons, well data, seismic reflection and refraction data, and the observed regional gravity field into the first crust-scale 3D structural model of the Beaufort-Mackenzie Basin. Many characteristics of this model reflect the complex geodynamic and tectonostratigraphic history of the basin. The Mesozoic-Cenozoic sedimentary part of the model comprises seven clastic units (predominantly sandy shales) of which the modelled thickness distributions allow to retrace the well-established history of the basin comprising a gradual north(east)ward shift of the main depocentres as well as diverse phases of localised erosion. As a result of this development, the present-day configuration of the basin reveals that the sedimentary units tend to be younger, more porous, and thus less dense towards the north at a constant depth level. By integrating three refraction seismic profiles and performing combined isostatic and 3D gravity modelling, we have modelled the sub-sedimentary basement of the Beaufort-Mackenzie Basin. The continental basement spans from unstretched domains (as thick as about 42 km) in the south to extremely thinned domains (of less than 5 km thickness) in the north where it probably represents transitional crust attached to the oceanic crust of the Canada Basin. The uppermost parts of the continental crust are less dense (ρ = 2710 kg/m3) and most probably made up by pre-Mesozoic meta-sediments overlying a heavier igneous and metamorphic crust (ρ = 2850 kg/m3). The presented crust-scale 3D structural model shows that the greatest

  1. From rebellious palpitations to the discovery of auricular fibrillation: contributions of Mackenzie, Lewis and Einthoven.

    PubMed

    Silverman, M E

    1994-02-15

    An irregular pulse, referred to as rebellious palpitations, delirium cordis and pulsus irregularis perpetuus, was a cause of speculation by physicians since early times. It was James Mackenzie, a Scottish general practitioner in Burnley, England, utilizing an ink-writing polygraph to record and label jugular venous pulses, who would pioneer in deciphering normal and abnormal cardiac rhythms. His key observation that the jugular "A wave" was lost in a patient who went from a normal to an irregular rhythm provided the first insight into the mechanism of auricular fibrillation. Similar jugular venous and arterial pulse findings were discovered by Cushny, Edmunds and Lewis in directly observed experimental auricular fibrillation. In 1909 Lewis in England and Rothberger and Winterberg in Vienna, taking advantage of Einthoven's newly developed string galvanometer, were the first to establish electrocardiographically that auricular fibrillation was the cause of pulsus irregularis perpetuus. PMID:8109554

  2. Monitoring ice break-up on the Mackenzie River, Canada, from MODIS Aqua and Terra observations

    NASA Astrophysics Data System (ADS)

    Muhammad, P.; Duguay, C. R.; Kang, K.

    2013-12-01

    Monitoring the response of river ice phenology to variability and changes in high-latitude climate conditions is critical for improving our understanding of northern hydrology and related impacts on geochemical and biological processes. Shorter ice cover duration, thinner ice, and earlier break-up also influence the winter road season, thereby influencing industrial development and the delivery of goods to northern communities. Increased upstream temperatures over the Mackenzie River Basin have caused shorter ice cover seasons, consequently changing the timing and severity of river ice flow in this high-latitude region. This study involves the analysis of Moderate Resolution Imaging Spectroradiometer (MODIS) Level 3 500-m snow products (Aqua and Terra), complemented with 250-m Level 1b data, to monitor ice cover during the break-up period on the Mackenzie River over the 2001-2013 period. Results from the analysis of 10 ice seasons (2003-2012) show that first day ice-off was observed between day of year (DY) 115-125 and ended between DY 145-155, resulting in average melt durations of about 30-40 days. Additional ice-on and ice-off days observed during 2003-2012 resulted from northern flowing entrained river ice that extended the break-up season until DY 155-163. Floating ice flowing northbound could therefore generate multiple periods of ice-cover and ice-free days at the same geographic location. During the ice break-up seasons from 2003-2012, ice melt was initiated by in situ melt over drainage basin (thermodynamic), especially between 61-62o N. However, ice break-up above the 62o N was more dynamically driven. In addition, ice jams were found to be largely controlled by river morphology.

  3. Stability Zone of Natural Gas Hydrates in a Permafrost-Bearing Region of the Beaufort-Mackenzie Basin: Study of a Feasible Energy Source (Geological Survey of Canada Contribution No.1999275)

    SciTech Connect

    Majorowicz, J. A. Hannigan, P. K.

    2000-03-15

    Analysis of geological and geophysical data from 150 wells in the Beaufort-Mackenzie region(study area between 68 deg. 30'-70 deg. 00'N and 131 deg. -39 deg. W) led to reinterpretation of the depth of methane hydrate stability and construction of the first contour maps displaying thickness of hydrate stability zones as well as hydrate stability zone thicknesses below permafrost. Calculations were based on construction of temperature-depth profiles incorporating regional heat-flow values, temperature at the base of ice-bearing permafrost, and models relating thermal conductivity with depth. Data analysis indicates the presence and extent of the methane hydrate stability zone is related mainly to the history of permafrost development and less so by the relatively small regional variations of temperature gradients. Analysis of well logs and other indicators in conjunction with knowledge of the hydrate stability zone allows reevaluation of the location of possible gas hydrate occurrences. Log analysis indicates that in the onshore and shallow sea area of the Beaufort-Mackenzie Basin, methane hydrate occurs in 27 wells. Fifteen of these locations coincides with underlying conventional hydrocarbon occurrences. Previous analyses place some of the hydrate occurrences at greater depths than proposed for the methane hydrate stability zone described in this study. Interpretation of geological cross sections reveals that hydrates are related mainly to sandy deltaic and delta-plain deposits in Iperk, Kugmallit, and Reindeer sequences although additional hydrate picks have been inferred in other sequences, such as Richards. Overlying permafrost may act as seal for hydrate accumulations; however, the thickness of permafrost and its related hydrate stability zone fluctuated during geological time. It is interpreted that only in the last tens of thousand of years (i.e., Sangamonian to Holocene), conditions for hydrates changed from nonstable to stable. During Early and Late

  4. Origin of the Mackenzie large igneous province and sourcing of flood basalts from layered intrusions

    NASA Astrophysics Data System (ADS)

    Day, J. M.; Pearson, D.

    2013-12-01

    The 1.27 Ga Coppermine continental flood basalt (CFB) in northern Canada represents the extrusive manifestation of the Mackenzie large igneous province (LIP) that includes the Mackenzie dyke swarm and the Muskox layered intrusion. New Re-Os isotope and highly siderophile element (HSE: Re, Pd, Pt, Ru, Ir, Os) abundance data are reported together with whole-rock major- and trace-element abundances and Nd isotopes to examine the behaviour of the HSE during magmatic differentiation and to place constraints on the extent of crustal interaction with mantle-derived melts. Mineral-chemical data are also reported for an unusual andesite glass flow (4.9 wt.% MgO) found in proximity to newly recognised picrites (>20 wt.% MgO) in the lowermost stratigraphy of the Coppermine CFB. Compositions of mineral phases in the andesite are similar to equivalent phases found in Muskox Intrusion chromitites and the melt composition is identical to Muskox chromite melt inclusions. Elevated HSE contents (e.g., 3.8 ppb Os) and the mantle-like initial Os isotope composition of this andesitic glass contrast strongly with oxygen isotope and lithophile element evidence for extensive crustal contamination. These signatures implicate an origin for the glass as a magma mingling product formed within the Muskox Intrusion during chromitite genesis. The combination of crust and mantle signatures define roles for both these reservoirs in chromitite genesis, but the HSE appear to be dominantly mantle-sourced. Combined with Nd isotope data that places the feeder for lower Coppermine CFB picrites and basalts within the Muskox Intrusion, this provides the strongest evidence yet for direct processing of some CFB within upper-crustal magma chambers. Modeling of absolute and relative HSE abundances in CFB reveal that HSE concentrations decrease with increasing fractionation for melts with <8×1 wt.% MgO in the Coppermine CFB, with picrites (>13.5wt.% MgO) from CFB having higher Os abundances than ocean island

  5. Development and application of a groundwater/surface-water flow model using MODFLOW-NWT for the Upper Fox River Basin, southeastern Wisconsin

    USGS Publications Warehouse

    Feinstein, D.T.; Fienen, M.N.; Kennedy, J.L.; Buchwald, C.A.; Greenwood, M.M.

    2012-01-01

    The Fox River is a 199-mile-long tributary to the Illinois River within the Mississippi River Basin in the states of Wisconsin and Illinois. For the purposes of this study the Upper Fox River Basin is defined as the topographic basin that extends from the upstream boundary of the Fox River Basin to a large wetland complex in south-central Waukesha County called the Vernon Marsh. The objectives for the study are to (1) develop a baseline study of groundwater conditions and groundwater/surface-water interactions in the shallow aquifer system of the Upper Fox River Basin, (2) develop a tool for evaluating possible alternative water-supply options for communities in Waukesha County, and (3) contribute to the methodology of groundwater-flow modeling by applying the recently published U.S. Geological Survey MODFLOW-NWT computer code, (a Newton formulation of MODFLOW-2005 intended for solving difficulties involving drying and rewetting nonlinearities of the unconfined groundwater-flow equation) to overcome computational problems connected with fine-scaled simulation of shallow aquifer systems by means of thin model layers. To simulate groundwater conditions, a MODFLOW grid is constructed with thin layers and small cell dimensions (125 feet per side). This nonlinear unconfined problem incorporates the streamflow/lake (SFR/LAK) packages to represent groundwater/surface-water interactions, which yields an unstable solution sensitive to initial conditions when solved using the Picard-based preconditioned-gradient (PCG2) solver. A particular problem is the presence of many isolated wet water-table cells over dry cells, causing the simulated water table to assume unrealistically high values. Attempts to work around the problem by converting to confined conditions or converting active to inactive cells introduce unacceptable bias. Application of MODFLOW-NWT overcomes numerical problem by smoothing the transition from wet to dry cells and keeps all cells active. The simulation is

  6. Mississippi Delta

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The streamers of clouds draped over the Gulf of Mexico in this true-color MODIS image from February 27, 2002, suggest that a cold, dry wind was blowing southward over the United States and began to pick up moisture over the Gulf, causing these strips of clouds. That the clouds didn't pick up until some distance from the coastline allowed MODIS to get a perfect view of the dynamic Gulf Coast environment spanning (left to right) Texas, Louisiana, Mississippi, Alabama, and Florida's Western Panhandle. The Mississippi River runs roughly down the center of the image, and is joined in Louisiana by the Red River coming in from the northwest. Over the past 7000 years, the actual delta, where the main river channel empties into the Gulf, has wandered around what we now think of as the Louisiana coast. Considering all the sediment visible in this image, it's not hard to imagine that the river carries about 2.4 billion kilograms of sediment into the Gulf each year. Deposition of some of this sediment has been building up the current delta, called the Birdfoot Delta, for obvious reasons, for about 700 years. The coastal waters are alive with microscopic organisms called phytoplankton, which contain colorful pigments, including chlorophyll, for harvesting sunlight. Beyond the sediment plume off Louisiana, the waters are very dark, which could indicate that a large amount of chlorophyll is present, absorbing lots of sunlight and causing the water to appear dark. Farther south, the waters appear bright blue, which could be a signature of coccolithophores, which use highly reflective calcium carbonate to build scaly coverings for themselves. The brighter offshore waters could also be caused by a blue-green algae called Trichodesmium, an organism that can not only harness carbon dioxide for photosynthesis, but can also take nitrogen from the air and turn it into a form that can be used by living organisms. Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

  7. Basin-Scale Exports vs. Coastal Delivery of Carbon, Nutrients and Particulates Above and Below Arctic River Deltas

    NASA Astrophysics Data System (ADS)

    Striegl, R. G.; Tank, S. E.; Weeks, G.; Holmes, R. M.; McClelland, J. W.

    2014-12-01

    Recent studies have substantially improved our understanding of water, sediment and materials exports by arctic rivers. Seasonality of exports, particularly during the spring freshet, is better quantified, as are the inland sources of water and sediment discharge and the source and chemical character of other material exports, including carbon and nutrients. Measurements on small rivers discharging directly to the Arctic Ocean and lacking complex deltas can accurately quantify local inputs to coastal regions. However, the majority of hydrologic inputs to the Arctic Ocean derive from 6 major Eurasian and North American rivers. Water, sediment, and chemical exports from these rivers are typically measured above head of tide, far inland, and commonly above large river deltas. These deltas settle particles and provide favorable environments for deposition, storage, and biogeochemical consumption, production, and transformation of aquatic carbon and nutrients. Consequently, basin exports measured above river deltas likely misrepresent actual delivery to coastal regions. In addition to accumulating sediment, observed and modeled arctic delta effects include enrichment of the organic content of suspended solids, increased dissolved organic carbon and nitrogen (DOC; DON) concentration, decreased inorganic nutrient concentration, and settling and likely increased bioavailability of particle associated contaminants, such as mercury. Increased DOC concentration in the Mackenzie River delta has also been associated with a change in DOC quality, with increased potential for biodegradation of DOC and decreased potential for photodegradation of DOC from head of tide to within the delta. For the most part, assessments of differences between head of tide basin exports and coastal delivery tend to be qualitative rather than quantitative, largely because of difficulties quantifying tidally affected flow. This points to the need to resolve data gaps, improve quantitative assessments

  8. Marine heat flow measurements across subsea permafrost limit in the eastern Mackenzie Trough, Canadian Beaufort Sea

    NASA Astrophysics Data System (ADS)

    Kim, Y. G.; Hong, J. K.; Jin, Y. K.; Riedel, M.; Melling, H.; Kang, S. G.; Dallimore, S.

    2015-12-01

    Marine heat flow measurements using a 5 m-long Ewing-type heat probe were made during Korean icebreaker R/V Araon's Arctic expeditions (ARA04C in 2013 and ARA05B in 2014) to better know the shallow subsurface thermal structure in the eastern slope of Mackenzie Trough, the Canadian Beaufort Sea, in which associative geological processes of permafrost degradation and gas hydrate dissociation occur because of long-term warming since the Last Glacial Maximum. Heat flow in the continental slope was collected for the first time and is rather higher than those from deep boreholes (up to a few km below the seafloor) in the continental shelf. However, the smaller geothermal gradient and thermal conductivity were observed from sites along a transect line across permafrost limit on the eastern slope of the trough. It is noted that geothermal gradients are relatively constant in the vicinity of permafrost limit but are much smaller (even minus) only at deeper depths with positive bottom water temperature. Reason for such distribution is unclear yet. Based on observed geothermal gradient and bottom water temperature, permafrost table shown in subbottom profile seems to be controlled not by temperature. On the other hand, our finding of permafrost evidence on the other subbottom profile located landward may support that permafrost limit in the trough is along with ~100 m isobath.

  9. Mississippi Delta

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The Mississippi River delta teems with sediment deposited by the river as it flows into the Gulf of Mexico in this true-color image captured by MODIS on October 15, 2001. The sediment, which is marked by brown swirls in the Gulf, provides nutrients for the bloom of phytoplankton visible as blue-green swirls off the coastline. In the high-resolution image the city of Memphis can be seen in the southwest corner of Tennessee, which is just to left of center at the top of the image. The brown coloration that encompasses Memphis and either side of the river, as flows north to south along the left side of the image, is the river's flood plain. Also visible, in the upper-right hand corner of the image is the southern end of the Appalachian Mountains.

  10. Analysis of the Beaufort-Mackenzie basin, Canada: Burial, thermal, and hydrocarbon histories

    SciTech Connect

    Tang, Jie; Lerche, I. )

    1991-03-01

    Using a 1-D thermal indicator tomography model, the burial, thermal, and hydrocarbon histories of the Jurassic-Tertiary sedimentary sequences are investigated in three structural zones of the Beaufort-Mackenzie basin. The specific objectives of this study are (1) to reconstruct the burial paths of Jurassic-Tertiary strata, the erosional amounts, and basement subsidence, from which the authors estimate the basin evolution, (2) to determine the thermal maturation levels of Jurassic-Tertiary source rocks, and (3) to investigate the relationship between the maturity levels of source rocks and present-day oil and gas occurrences. The reconstructed geohistories of seven wells indicate two stages of tectonics in the study area. The first stage is a rifting event from Jurassic to early Miocene. The second stage is one of post-rifting uplift and erosion as well as thermal subsidence. Associated with the tectonic activities, inversion of vitrinite reflectance data in the seven wells yielded heating episodes from around 150 to 20 m.y. ago in the Tuktoyaktuk Peninsula province and from around 60 to 10 m.y. ago in the central and western parts of the basin. Comparison of the thermal maturation patterns with oil and gas occurrences in five of the wells indicates that the oil of Cretaceous reservoirs may come vertically from the Husky Formation, while the oil and gas of Tertiary reservoirs and the gas of the Cretaceous may undergo extensive horizontal migration. The combination of thermal history, hydrocarbon generation history, and TOC of source rocks, as well as the relationship between source and reservoir rocks, indicates that exploration for oil and gas should likely concentrate on both the central part and on the Tuktoyaktuk Peninsula of the study area.

  11. Multi-decadal increases in dissolved organic carbon and alkalinity flux from the Mackenzie drainage basin to the Arctic Ocean

    NASA Astrophysics Data System (ADS)

    Tank, Suzanne E.; Striegl, Robert G.; McClelland, James W.; Kokelj, Steven V.

    2016-05-01

    Riverine exports of organic and inorganic carbon (OC, IC) to oceans are intricately linked to processes occurring on land. Across high latitudes, thawing permafrost, alteration of hydrologic flow paths, and changes in vegetation may all affect this flux, with subsequent implications for regional and global carbon (C) budgets. Using a unique, multi-decadal dataset of continuous discharge coupled with water chemistry measurements for the Mackenzie River, we show major increases in dissolved OC (DOC) and IC (as alkalinity) fluxes since the early 1970s, for a watershed that covers 1.8 M km2 of northwestern Canada, and provides substantial inputs of freshwater and biogeochemical constituents to the Arctic Ocean. Over a 39-year period of record, DOC flux at the Mackenzie mouth increased by 39.3% (44.5 ± 22.6 Gmol), while alkalinity flux increased by 12.5% (61.5 ± 60.1 Gmol). Isotopic analyses and substantial increases in sulfate flux indicate that increases in alkalinity are driven by accelerating sulfide oxidation, a process that liberates IC from rock and soils in the absence of CO2 consumption. Seasonal and sub-catchment trends suggest that permafrost thaw plays an important role in the observed increases in DOC and alkalinity: sub-catchment increases for all constituents are confined to northern, permafrost-affected regions, while observed increases in autumn to winter are consistent with documented landscape-scale changes that have resulted from changing thaw dynamics. This increase in DOC and sulfide-derived alkalinity represents a substantial intensification of land-to-ocean C mobilization, at a level that is significant within the regional C budget. The change we observe, for example, is similar to current and projected future rates of CO2 consumption by weathering in the Mackenzie basin.

  12. Delta III—an evolutionary delta growth

    NASA Astrophysics Data System (ADS)

    Arvesen, R. J.; Simpson, J. S.

    1996-03-01

    In order to remain competitive in the future and expand the McDonnell Douglas Aerospace market share, MDA has developed an expendable launch system strategy that devices cost-effective launch systems from the Delta II with a growth vehicle configuration called Delta III. The Delta III evolves from the Delta II launch system through development of a larger payload fairing (4-meter diameter), new cryogenically propelled upper stage, new first stage fuel tank, and larger strap-on solid rocket motors. We are developing the Delta III using Integrated Product Development Teams that capitalize on the experience base that has led us to a world record breaking mission success of 49 consecutive Delta II missions. The Delta III first-launch capability is currently planned for the spring of 1998 in support of our first spacecraft customer, Hughes Space and Communications International.

  13. The Delta 2 launcher

    NASA Astrophysics Data System (ADS)

    Ousley, Gilbert W., Sr.

    1991-12-01

    The utilization of the Delta 2 as the vehicle for launching Aristoteles into its near Sun synchronous orbit is addressed. Delta is NASA's most reliable launch vehicle and is well suited for placing the present Aristoteles spacecraft into a 400 m circular orbit. A summary of some of the Delta 2 flight parameters is presented. Diagrams of a typical Delta 2 two stage separation are included along with statistics on delta reliability and launch plans.

  14. Sensitivity of Arctic Permafrost Carbon in the Mackenzie River Basin: A substrate addition and incubation experiment

    NASA Astrophysics Data System (ADS)

    Hedgpeth, A.; Beilman, D.; Crow, S. E.

    2014-12-01

    Arctic soil organic matter (SOM) mineralization processes are fundamental to the functioning of high latitude soils in relation to nutrients, stability, and feedbacks to atmospheric CO2 and climate. The arctic permafrost zone covers 25% of the northern hemisphere and contains 1672Pg of soil carbon (C). 88% of this C currently resides in frozen soils that are vulnerable to environmental change. For instance, arctic growing seasons may be lengthened, resulting in an increase in plant productivity and rate of below ground labile C inputs as root exudates. Understanding controls on Arctic SOM dynamics requires recognition that labile C inputs have the potential to significantly affect mineralization of previously stable SOM, also known as 'priming effects'. We conducted a substrate addition incubation experiment to quantify and compare respiration in highly organic (42-48 %C) permafrost soils along a north-south transect in western Canada. Near surface soils (10-20 cm) were collected from permafrost peatland sites in the Mackenzie River Basin from 69.2-62.6°N. The surface soils are fairly young (Δ14C values > -140.0) and can be assumed to contain relatively reactive soil carbon. To assess whether addition of labile substrate alters SOM decomposition dynamics, 4.77-11.75 g of permafrost soil were spiked with 0.5 mg D-glucose g-1 soil and incubated at 5°C. A mass balance approach was used to determin substrate-induced respiration and preliminary results suggest a potential for positive priming in these C-rich soils. Baseline respiration rates from the three sites were similar (0.067-0.263 mg CO2 g-1 soil C) yet show some site-specific trends. The rate at which added substrate was utilized within these soils suggests that other factors besides temperature and soil C content are controlling substrate consumption and its effect on SOM decomposition. Microbial activity can be stimulated by substrate addition to such an extent that SOM turnover is enhanced, suggesting that

  15. Completing the calculation of Brodsky-Lepage-Mackenzie corrections to B{yields}X{sub s}{gamma}

    SciTech Connect

    Misiak, Mikolaj; Poradzinski, Michal

    2011-01-01

    Perturbative O({alpha}{sub s}{sup 2}) corrections to B(B{yields}X{sub s}{gamma}) in the Brodsky-Lepage-Mackenzie approximation receive contributions from two-, three-, and four-body final states. While all the two-body results are well established by now, the other ones have remained incomplete for several years. Here, we calculate the last contribution that has been missing to date, namely, the one originating from interference of the current-current and gluonic dipole operators (K{sub 18}{sup (2){beta}}{sub 0} and K{sub 28}{sup (2){beta}}{sub 0}). Moreover, we confirm all the previously known results for Brodsky-Lepage-Mackenzie corrections to the photon energy spectrum that involve the current-current operators (e.g., K{sub 22}{sup (2){beta}}{sub 0} and K{sub 27}{sup (2){beta}}{sub 0}). Finally, we also confirm the recent findings of Ferroglia and Haisch on self-interference of the gluonic dipole operator (K{sub 88}{sup (2){beta}}{sub 0}).

  16. The influence of volcanological and sedimentological processes on diamond grade distribution in kimberlites: examples from the EKATI Diamond Mine, NWT, Canada

    NASA Astrophysics Data System (ADS)

    Porritt, Lucy A.; Cas, R. A. F.; Ailleres, L.; Oshust, P.

    2011-10-01

    The distribution of diamonds within individual kimberlite pipes is poorly documented in the public domain due to the proprietary nature of the data. The study of the diamond distribution within two pipes, Fox and Koala, from the EKATI Diamond Mine, NWT, Canada, in conjunction with detailed facies models has shown several distinct relationships of deposit type and grade distribution. In both pipes, the lithological facies represent grade units which can be distinguished from each other in terms of relative size and abundance of diamonds. A positive relationship between olivine grain size and abundance with diamond size and abundance is observed, indicating that sorting of fragmental kimberlites influences diamond distribution. Though surface geological processes do not control the diamond potential of the erupting magma, they can be responsible for concentrating diamonds into economically significant proportions. A good understanding of the eruption, transport and depositional processes responsible for the individual lithological units and the diamond distribution within them is important for successful resource estimation. This may lead to recognition of areas suitable for selective mining, making a marginal deposit economic.

  17. Fan deltas and braid deltas: conceptual problems

    SciTech Connect

    McPherson, J.G.; Shanmugam, G.; Moiola, R.J.

    1986-05-01

    The concept of fan deltas has been widely misinterpreted in the geologic literature. A true fan delta is defined as an alluvial fan deposited into a standing body of water. Such sequences are of limited areal extent and are, as expected, uncommon in the rock record. By contrast, braid deltas (herein defined), formed by progradation of a braided fluvial system into a standing body of water, are a common geomorphic feature in many modern settings, and their deposits are common in the geologic record. Braid-delta sequences are often identified as fan deltas, on the false premise that coarse-grained deposits in a deltaic setting are always part of an alluvial fan complex. The authors find that most published examples of so called fan deltas contain no direct evidence for the presence of an alluvial fan. Even in examples where an alluvial fan could be documented, the authors found that, in many cases, the alluvial fan complex was far removed from the shoreline, separated by an extensive braid plain. The authors suggest that such systems are better classified as braid deltas. They consider that it is essential to distinguish the environmental setting of true fan deltas from that of braid deltas. Misclassification will lead to incorrect interpretations of expected facies, sandstone geometry, reservoir quality, and tectonic settings. Criteria based on geometry, vertical and lateral lithofacies associations, and paleocurrent patterns should be used to correctly identify and distinguish these depositional systems.

  18. Motor programming is not the only process which can influence RT: some thoughts on the Marteniuk and MacKenzie analysis.

    PubMed

    Klapp, S T

    1981-12-01

    The current status of research on the memory drum theory is evaluated with emphasis on the issues raised by Marteniuk and MacKenzie (1981). A general theme emerging from this review is that response programming is not the only process which can influence RT and that distinguishing programming from non-programming effects clarifies rather than "clouds" the issues.

  19. delta-Hexachlorocyclohexane (delta-HCH)

    Integrated Risk Information System (IRIS)

    delta - Hexachlorocyclohexane ( delta - HCH ) ; CASRN 319 - 86 - 8 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Ass

  20. Simulation of Water Sources and Precipitation Recycling for the MacKenzie, Mississippi and Amazon River Basins

    NASA Technical Reports Server (NTRS)

    Bosilovich, Michael G.; Chern, Jiun-Dar

    2005-01-01

    An atmospheric general circulation model simulation for 1948-1997 of the water budgets for the MacKenzie, Mississippi and Amazon River basins is presented. In addition to the water budget, we include passive tracers to identify the geographic sources of water for the basins, and the analysis focuses on the mechanisms contributing to precipitation recycling in each basin. While each basin s precipitation recycling has a strong dependency on evaporation during the mean annual cycle, the interannual variability of the recycling shows important relationships with the atmospheric circulation. The MacKenzie River basin has only a weak interannual dependency on evaporation, where the variations in zonal moisture transport from the Pacific Ocean can affect the basin water cycle. On the other hand, the Mississippi River basin has strong interannual dependencies on evaporation. While the precipitation recycling weakens with increased low level jet intensity, the evaporation variations exert stronger influence in providing water vapor for convective precipitation at the convective cloud base. High precipitation recycling is also found to be partly connected to warm SSTs in the tropical Pacific Ocean. The Amazon River basin evaporation exhibits small interannual variations, so that the interannual variations of precipitation recycling are related to atmospheric moisture transport from the tropical south Atlantic Ocean. Increasing SSTs over the 50-year period are causing increased easterly transport across the basin. As moisture transport increases, the Amazon precipitation recycling decreases (without real time varying vegetation changes). In addition, precipitation recycling from a bulk diagnostic method is compared to the passive tracer method used in the analysis. While the mean values are different, the interannual variations are comparable between each method. The methods also exhibit similar relationships to the terms of the basin scale water budgets.

  1. The Current Tectonics of the Yukon and Adjacent Area

    NASA Astrophysics Data System (ADS)

    Hyndman, R. D.; Leonard, L. J.

    2014-12-01

    The current tectonics across the Yukon and adjacent areas of western Northwest Territories (NWT) and northern British Columbia appear to be driven primarily by the Yakutat Terrane collision, an "indenter" in the corner of the Gulf of Alaska. GPS data show 1-10 mm/yr northward and eastward, decreasing inland. The rates from earthquake statistics are similar although there are important discrepancies. The eastern Cordillera earthquake mechanisms are mainly thrust in the Mackenzie Mountains of southwestern NWT where the Cordillera upper crust is overthrusting the craton. To the north, the mechanisms are mainly strike-slip in the Richardson Mountains that appear to lie along the edge of the craton. The deformation appears to be limited to the hot and weak Cordillera with the strong craton providing an irregular eastern boundary. For example, there is an eastward bow in the craton edge and the deformation in the Mackenzie Mountains. On the Beaufort Sea margin in the region of the Mackenzie Delta there appears to be a type of "subduction zone" with the continent very slowly overthrusting the oceanic plate, a process that has continued since at least the Cretaceous. A northward moving continental margin block is bounded by left lateral faulting in the west (Canning Displacement Zone of eastern Alaska) and right lateral faulting in the east (Richardson Mountains in eastern Yukon). There is almost no seismicity on this thrust belt but as for some other subduction zones such as Cascadia there is the potential for very infrequent great earthquakes.

  2. Paleolimnological assessment of riverine and atmospheric pathways and sources of metal deposition at a floodplain lake (Slave River Delta, Northwest Territories, Canada).

    PubMed

    MacDonald, Lauren A; Wiklund, Johan A; Elmes, Matthew C; Wolfe, Brent B; Hall, Roland I

    2016-02-15

    Growth of natural resource development in northern Canada has raised concerns about the effects on downstream aquatic ecosystems, but insufficient knowledge of pre-industrial baseline conditions continues to undermine ability of monitoring programs to distinguish industrial-derived contaminants from those supplied by natural processes. Here, we apply a novel paleolimnological approach to define pre-industrial baseline concentrations of 13 priority pollutant metals and vanadium and assess temporal changes, pathways and sources of these metals at a flood-prone lake (SD2) in the Slave River Delta (NWT, Canada) located ~500 km north of Alberta's oil sands development and ~140 km south of a former gold mine at Yellowknife, NWT. Results identify that metal concentrations, normalized to lithium concentration, are not elevated in sediments deposited during intervals of high flood influence or low flood influence since onset of oil sands development (post-1967) relative to the 1920-1967 baseline established at SD2. When compared to a previously defined baseline for the upstream Athabasca River, several metal-Li relations (Cd, Cr, Ni, Zn, V) in post-1967 sediments delivered by floodwaters appear to plot along a different trajectory, suggesting that the Peace and Slave River watersheds are important natural sources of metal deposition at the Slave River Delta. However, analysis revealed unusually high concentrations of As deposited during the 1950s, an interval of very low flood influence at SD2, which corresponded closely with emission history of the Giant Mine gold smelter indicating a legacy of far-field atmospheric pollution. Our study demonstrates the potential for paleolimnological characterization of baseline conditions and detection of pollution from multiple pathways in floodplain ecosystems, but that knowledge of paleohydrological conditions is essential for interpretation of contaminant profiles. PMID:26688053

  3. Paleolimnological assessment of riverine and atmospheric pathways and sources of metal deposition at a floodplain lake (Slave River Delta, Northwest Territories, Canada).

    PubMed

    MacDonald, Lauren A; Wiklund, Johan A; Elmes, Matthew C; Wolfe, Brent B; Hall, Roland I

    2016-02-15

    Growth of natural resource development in northern Canada has raised concerns about the effects on downstream aquatic ecosystems, but insufficient knowledge of pre-industrial baseline conditions continues to undermine ability of monitoring programs to distinguish industrial-derived contaminants from those supplied by natural processes. Here, we apply a novel paleolimnological approach to define pre-industrial baseline concentrations of 13 priority pollutant metals and vanadium and assess temporal changes, pathways and sources of these metals at a flood-prone lake (SD2) in the Slave River Delta (NWT, Canada) located ~500 km north of Alberta's oil sands development and ~140 km south of a former gold mine at Yellowknife, NWT. Results identify that metal concentrations, normalized to lithium concentration, are not elevated in sediments deposited during intervals of high flood influence or low flood influence since onset of oil sands development (post-1967) relative to the 1920-1967 baseline established at SD2. When compared to a previously defined baseline for the upstream Athabasca River, several metal-Li relations (Cd, Cr, Ni, Zn, V) in post-1967 sediments delivered by floodwaters appear to plot along a different trajectory, suggesting that the Peace and Slave River watersheds are important natural sources of metal deposition at the Slave River Delta. However, analysis revealed unusually high concentrations of As deposited during the 1950s, an interval of very low flood influence at SD2, which corresponded closely with emission history of the Giant Mine gold smelter indicating a legacy of far-field atmospheric pollution. Our study demonstrates the potential for paleolimnological characterization of baseline conditions and detection of pollution from multiple pathways in floodplain ecosystems, but that knowledge of paleohydrological conditions is essential for interpretation of contaminant profiles.

  4. Delta launcher enhanced

    NASA Astrophysics Data System (ADS)

    1987-08-01

    The next-generation, 'Delta II' version of the Delta expendable launch vehicle will be able to launch over 4000 lbs into geosynchronous transfer orbit (GTO), as required by the USAF's Navstar GPS; the current Delta 3920 configuration can loft only 2800 lbs into GEO. Three distinct growth configurations of the Delta II are planned: the 6925, whose booster propellant tanks will be extended by 12 ft; the 7925, whose improved booster engine will increase nozzle expansion ratio from 8:1 to 12:1; and the 'enhanced ' Delta II, with stretched graphite-epoxy solid rocket motor cases. In this final form, Delta II will boost 4010 lbs into GTO, or 11,110 lbs into LEO.

  5. Synoptic and time-series stable isotope surveys of the Mackenzie River from Great Slave Lake to the Arctic Ocean, 2003 to 2006

    NASA Astrophysics Data System (ADS)

    Yi, Yi; Gibson, John J.; Hélie, Jean-François; Dick, Terry A.

    2010-03-01

    SummaryWe report oxygen and hydrogen isotopic composition of river discharges in the main stem and tributaries in Mackenzie River system, Canada, based upon a synoptic survey and a time-series monitoring program undertaken between 2003 and 2006. The water isotope signals in the Mackenzie River system exhibit distinct geographic variations. Isotopic results from the comprehensive synoptic survey offset from meteoric water lines in δ18O- δ2H space, and suggest a snowmelt-driven discharge regime with mixing between heavy-isotope depleted discharge from Liard River and Mackenzie Mountains, and evaporatively-enriched water from Great Slave Lake catchment. Based upon these isotopic data in river discharge, we propose an evaporative-mixing line for the Mackenzie River system ( δ2H = 6.0 × δ18O - 40.8), which highlights the integrated effects of the two most important hydrologic processes (i.e., evaporation and mixing). Time-series investigation of water isotope signatures and river discharge at three key hydrometric stations demonstrates the isotopic response to the strong seasonality of river discharge in northern Canada. In general, isotopic compositions in river discharge tend to be negatively correlated with discharge amount, which is a typical snowmelt-driven isotope-discharge pattern. However, low flow conditions are found to be noisy with a wide range of isotopic variability. More importantly, we also observe that extreme high flow events, especially in the Liard River, appear to be unexpectedly enriched in heavy isotopes, which indicate contributions from evaporated water that are probably derived from wetland surface storage. This is a situation, which produces a reversal in the isotope-discharge pattern and marks important episodes that may impact chemical and riverine/estuarine biotic processes at times of extremely high runoff.

  6. Estimating impacts of snow cover on net ecosystem exchange near Daring Lake, NWT, Canada (65oN, 111oW)

    NASA Astrophysics Data System (ADS)

    Luus, K. A.; Kelly, R. E.; Lin, J. C.; Humphreys, E. R.; Lafleur, P.

    2010-12-01

    Arctic CO2 flux is influenced by the spatial distribution, accumulation, and phenology of snow. Regions with greater net primary productivity tend to accumulate greater snowfall, and areas receiving greater snowfall have higher soil temperatures, enabling greater rates of winter respiration. During snow melt, the spatial distributions of remaining snow influence the patterns of CO2 release. However, cryospheric influences on CO2 distributions are not typically included in models of net ecosystem exchange. The objective of this research was therefore to investigate: 1) the influence of snow cover distributions on CO2 flux during snow melt at four sites located near Daring Lake, NWT, Canada; and 2) the amount of variation in CO2 flux due to arctic land cover class and snow distributions captured by the remote sensing based Vegetation Photosysthesis and Respiration Model (VPRM), which does not contain explicit arctic land cover class or cryospheric parameterizations. Snow cover distributions were monitored twice daily throughout the 2010 snow melt period (May-June) using Moultrie I-65 game cameras over four arctic land cover classes: fen, tall shrub, short shrub and mixed tundra. At each site, CO2 flux data was collected using an open path infrared gas analyzer eddy covariance system. Initial analysis consisted of classifying snow cover locations and extent in each image. Footprint modeling was then conducted in order to assess the impact of snow cover distributions on CO2 flux during melt. In order to assess the amount of variability in net ecosystem exchange due to snow cover captured by VPRM, associations between vegetation cover, snow extents and CO2 flux were first upscaled using classification of Landsat snow cover and land cover class. VPRM was then run over the same region. VPRM output was statistically compared to upscaled CO2. Although VPRM contains few land surface parameters, it is not hindered by gaps in Landsat data due to cloud cover, or diminished

  7. Influence of increasing active-layer depth and continued permafrost degradation on carbon, water and energy fluxes over two forested permafrost landscapes in the Taiga Plains, NWT, Canada

    NASA Astrophysics Data System (ADS)

    Sonnentag, O.; Baltzer, J.; Chasmer, L. E.; Detto, M.; Marsh, P.; Quinton, W. L.

    2012-12-01

    Recent research suggests an increase in active-layer depth (ALD) in the continuous permafrost zone and degradation of the discontinuous permafrost zone into seasonally frozen. Increasing ALD and continued permafrost degradation will have far-reaching consequences for northern ecosystems including altered regional hydrology and the exposure of additional soil organic carbon (C) to microbial decomposition. These changes might cause positive or negative net feedbacks to the climate system by altering important land surface properties and/or by releasing stored soil organic C to the atmosphere as CO2 and/or CH4. Knowledge gaps exist regarding the links between increasing ALD and/or permafrost degradation, regional hydrology, vegetation composition and structure, land surface properties, and CO2 and CH4 sink-source strengths. The goal of our interdisciplinary project is to shed light on these links by providing a mechanistic understanding of permafrost-thawing consequences for hydrological, ecophysiological and biogeochemical processes at two forested permafrost landscapes in the Taiga Plains, NWT, Canada: Scotty Creek and Havikpak Creek in the discontinuous and in the continuous permafrost zones, respectively (Fig.). The sites will be equipped with identical sets of instrumentation (start: 2013), to measure landscape-scale net exchanges of CO2, CH4, water and energy with the eddy covariance technique. These measurements will be complemented by repeated surveys of surface and frost table topography and vegetation, by land cover-type specific fluxes of CO2 and CH4 measured with a static chamber technique, and by remote sensing-based footprint analysis. With this research we will address the following questions: What is the net effect of permafrost thawing-induced biophysical and biogeochemical feedbacks to the climate system? How do these two different types of feedback differ between the discontinuous and continuous permafrost zones? Is the decrease (increase) in net CO

  8. Pen Branch delta expansion

    SciTech Connect

    Nelson, E.A.; Christensen, E.J.; Mackey, H.E.; Sharitz, R.R.; Jensen, J.R.; Hodgson, M.E.

    1984-02-01

    Since 1954, cooling water discharges from K Reactor ({anti X} = 370 cfs {at} 59 C) to Pen Branch have altered vegetation and deposited sediment in the Savannah River Swamp forming the Pen Branch delta. Currently, the delta covers over 300 acres and continues to expand at a rate of about 16 acres/yr. Examination of delta expansion can provide important information on environmental impacts to wetlands exposed to elevated temperature and flow conditions. To assess the current status and predict future expansion of the Pen Branch delta, historic aerial photographs were analyzed using both basic photo interpretation and computer techniques to provide the following information: (1) past and current expansion rates; (2) location and changes of impacted areas; (3) total acreage presently affected. Delta acreage changes were then compared to historic reactor discharge temperature and flow data to see if expansion rate variations could be related to reactor operations.

  9. Delta hepatitis in Malaysia.

    PubMed

    Sinniah, M; Dimitrakakis, M; Tan, D S

    1986-06-01

    Sera from one hundred and fifty nine Malaysian individuals were screened for the prevalence of delta markers. These included 15 HBsAg positive homosexuals, 16 acute hepatitis B cases, 9 chronic hepatitis B patients, 13 healthy HBsAg carriers and 106 intravenous (i.v.) drug abusers, of whom 27 were positive for HBsAg only and the rest were anti-HBc IgG positive but HBsAg negative. The prevalence of delta markers in the homosexuals was found to be 6.7%, in the HBsAg positive drug abusers 17.8%, in acute hepatitis B cases 12.5%. No evidence of delta infection was detected in healthy HBsAg carriers, chronic hepatitis B cases and HBsAg negative i.v. drug abusers. With reference to i.v. drug abusers, the prevalence of delta markers was higher in Malays (23%) than in Chinese (7%) although the latter had a higher HBsAg carrier rate. Although the HBsAg carrier rate in the homosexuals was high, their delta prevalence rate was low as compared to drug abusers. In Malaysia, as in other non-endemic regions, hepatitis delta virus transmission appeared to occur mainly via the parenteral and sexual routes. This is the first time in Malaysia that a reservoir of delta infection has been demonstrated in certain groups of the population at high risk for hepatitis B. PMID:3787309

  10. Ecological recovery in an Arctic delta following widespread saline incursion.

    PubMed

    Lantz, Trevor C; Kokelj, Steve V; Fraser, Robert H

    2015-01-01

    Arctic ecosystems are vulnerable to the combined effects of climate change and a range of other anthropogenic perturbations. Predicting the cumulative impact of these stressors requires an improved understanding of the factors affecting ecological resilience. In September of 1999, a severe storm surge in the Mackenzie Delta flooded alluvial surfaces up to 30 km inland from the coast with saline waters, driving environmental impacts unprecedented in the last millennium. In this study we combined field monitoring of permanent sampling plots with an analysis of the Landsat archive (1986-2011) to explore the factors affecting the recovery of ecosystems to this disturbance. Soil salinization following the 1999 storm caused the abrupt dieback of more than 30,000 ha of tundra vegetation. Vegetation cover and soil chemistry show that recovery is occurring, but the rate and spatial extent are strongly dependent on vegetation type, with graminoid- and upright shrub-dominated areas showing recovery after a decade, but dwarf shrub tundra exhibiting little to no recovery over this period. Our analyses suggest that recovery from salinization has been strongly influenced by vegetation type and the frequency of freshwater flooding following the storm. With increased ocean storm activity, rising sea levels, and reduced sea ice cover, Arctic coastal ecosystems will be more likely to experience similar disturbances in the future, highlighting the importance of combining field sampling with regional-scale remote sensing in efforts to detect, understand, and anticipate environmental change.

  11. Ecological recovery in an Arctic delta following widespread saline incursion.

    PubMed

    Lantz, Trevor C; Kokelj, Steve V; Fraser, Robert H

    2015-01-01

    Arctic ecosystems are vulnerable to the combined effects of climate change and a range of other anthropogenic perturbations. Predicting the cumulative impact of these stressors requires an improved understanding of the factors affecting ecological resilience. In September of 1999, a severe storm surge in the Mackenzie Delta flooded alluvial surfaces up to 30 km inland from the coast with saline waters, driving environmental impacts unprecedented in the last millennium. In this study we combined field monitoring of permanent sampling plots with an analysis of the Landsat archive (1986-2011) to explore the factors affecting the recovery of ecosystems to this disturbance. Soil salinization following the 1999 storm caused the abrupt dieback of more than 30,000 ha of tundra vegetation. Vegetation cover and soil chemistry show that recovery is occurring, but the rate and spatial extent are strongly dependent on vegetation type, with graminoid- and upright shrub-dominated areas showing recovery after a decade, but dwarf shrub tundra exhibiting little to no recovery over this period. Our analyses suggest that recovery from salinization has been strongly influenced by vegetation type and the frequency of freshwater flooding following the storm. With increased ocean storm activity, rising sea levels, and reduced sea ice cover, Arctic coastal ecosystems will be more likely to experience similar disturbances in the future, highlighting the importance of combining field sampling with regional-scale remote sensing in efforts to detect, understand, and anticipate environmental change. PMID:26255366

  12. Delta Scuti stars: Theory

    SciTech Connect

    Guzik, J.A.

    1998-03-01

    The purpose of asteroseismology is not only to derive the internal structure of individual stars from their observed oscillation frequencies, but also to test and extend one`s understanding of the physics of matter under the extremes of temperature, density, and pressure found in stellar interiors. In this review, the author hopes to point out what one can learn about the Sun by studying {delta} Scuti stars, as well as what one can learn about stars more massive or evolved than the Sun. He discusses some of the difficulties in theoretical approaches to asteroseismology for {delta} Scuti stars, using FG Vir, {delta} Scuti, and CD-24{degree} 7599 as examples.

  13. Nile Delta, Egypt

    NASA Technical Reports Server (NTRS)

    1982-01-01

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

  14. Nile River Delta, Egypt

    NASA Technical Reports Server (NTRS)

    1984-01-01

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

  15. Modeling river delta formation.

    PubMed

    Seybold, Hansjörg; Andrade, José S; Herrmann, Hans J

    2007-10-23

    A model to simulate the time evolution of river delta formation process is presented. It is based on the continuity equation for water and sediment flow and a phenomenological sedimentation/erosion law. Different delta types are reproduced by using different parameters and erosion rules. The structures of the calculated patterns are analyzed in space and time and compared with real data patterns. Furthermore, our model is capable of simulating the rich dynamics related to the switching of the mouth of the river delta. The simulation results are then compared with geological records for the Mississippi River. PMID:17940031

  16. Man made deltas

    PubMed Central

    Maselli, Vittorio; Trincardi, Fabio

    2013-01-01

    The review of geochronological and historical data documents that the largest southern European deltas formed almost synchronously during two short intervals of enhanced anthropic pressure on landscapes, respectively during the Roman Empire and the Little Ice Age. These growth phases, that occurred under contrasting climatic regimes, were both followed by generalized delta retreat, driven by two markedly different reasons: after the Romans, the fall of the population and new afforestation let soil erosion in river catchments return to natural background levels; since the industrial revolution, instead, flow regulation through river dams overkill a still increasing sediment production in catchment basins. In this second case, furthermore, the effect of a reduced sediment flux to the coasts is amplified by the sinking of modern deltas, due to land subsidence and sea level rise, that hampers delta outbuilding and increases the vulnerability of coastal zone to marine erosion and flooding. PMID:23722597

  17. Man made deltas.

    PubMed

    Maselli, Vittorio; Trincardi, Fabio

    2013-01-01

    The review of geochronological and historical data documents that the largest southern European deltas formed almost synchronously during two short intervals of enhanced anthropic pressure on landscapes, respectively during the Roman Empire and the Little Ice Age. These growth phases, that occurred under contrasting climatic regimes, were both followed by generalized delta retreat, driven by two markedly different reasons: after the Romans, the fall of the population and new afforestation let soil erosion in river catchments return to natural background levels; since the industrial revolution, instead, flow regulation through river dams overkill a still increasing sediment production in catchment basins. In this second case, furthermore, the effect of a reduced sediment flux to the coasts is amplified by the sinking of modern deltas, due to land subsidence and sea level rise, that hampers delta outbuilding and increases the vulnerability of coastal zone to marine erosion and flooding. PMID:23722597

  18. Changing Cold Regions: Addressing Atmospheric, Cryospheric, Ecological and Hydrological Change in the Saskatchewan and Mackenzie River Basins, Canada

    NASA Astrophysics Data System (ADS)

    Pomeroy, J. W.; Wheater, H. S.; Quinton, W. L.; Stewart, R. E.

    2013-05-01

    The cold interior region of Western Canada east of the Continental Divide from the US border to the Arctic Ocean has one of the world's most extreme and variable climates and is experiencing rapid environmental change. Climate warming and precipitation change have resulted in altered patterns of snowfall and snowmelt, conversion of snowfall to rainfall, loss of glaciated area and thawing of permafrost. Effects of these changes on terrestrial ecosystems include changing alpine and arctic treelines, extreme variability in Prairie wetland extent and storage of subsurface water in soil and groundwater, "browning" of the boreal forest and prairie aspen woodlands, forest conversion to wetlands in areas of permafrost loss, increased tundra shrub height and coverage, with associated impacts on snow accumulation and melt and ground thaw regimes. These atmospheric, cryospheric and ecological changes have produced changes to water storage and cycling with lower, earlier and more variable streamflow from the Western Cordillera, earlier and more variable Prairie streamflow, more variable agricultural soil moisture, substantially earlier and sometimes higher streamflows with greater winter baseflows in the North, and indications of changes in extreme precipitation events and resulting flooding and drought. The recently formed Changing Cold Regions Network (CCRN) will investigate the integrated response of mountain, boreal forest, prairie and sub-arctic biomes to climate change at the scales of the Saskatchewan and Mackenzie River Basins and the regional climate system. The multi-prong approach will first inventory and evaluate observable recent change in the Earth system state, fluxes and variability, and then explore the complex interrelationships of changing Earth system processes through the development of improved models and their application in diagnosis and prediction at multiple scales, from small headwater basins to large river basins, major biomes and the regional

  19. Turbulent heat exchanger {Delta}T and {Delta}P

    SciTech Connect

    Steinmeyer, D.

    1996-12-31

    Optimum pressure drop ({Delta}P) and temperature difference ({Delta}T) in turbulent flow heat exchangers are presented in three frameworks: as quantitatively defined by fluid properties, the value of energy and the cost of heat exchange surface (with a little help from a relationship between [power/mass] and heat transfer); as the energy cost for heat recovery (with the {Delta}T cost being about equal to the heat exchanger cost and the {Delta}P cost being about 1/3 as great); and as the second law lost work inherent in heat exchange (with the {Delta}T loss being {approximately}3 times the {Delta}T loss).

  20. Ganges River Delta

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The Ganges River forms an extensive delta where it empties into the Bay of Bengal. The delta is largely covered with a swamp forest known as the Sunderbans, which is home to the Royal Bengal Tiger. It is also home to most of Bangladesh, one of the world's most densely populated countries. Roughly 120 million people live on the Ganges Delta under threat of repeated catastrophic floods due to heavy runoff of meltwater from the Himalayas, and due to the intense rainfall during the monsoon season. This image was acquired by Landsat 7's Enhanced Thematic Mapper plus (ETM+) sensor on February 28, 2000. This is a false-color composite image made using green, infrared, and blue wavelengths. Image provided by the USGS EROS Data Center Satellite Systems Branch

  1. Delta II Mars Pathfinder

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Final preparations for lift off of the DELTA II Mars Pathfinder Rocket are shown. Activities include loading the liquid oxygen, completing the construction of the Rover, and placing the Rover into the Lander. After the countdown, important visual events include the launch of the Delta Rocket, burnout and separation of the three Solid Rocket Boosters, and the main engine cutoff. The cutoff of the main engine marks the beginning of the second stage engine. After the completion of the second stage, the third stage engine ignites and then cuts off. Once the third stage engine cuts off spacecraft separation occurs.

  2. Origins of subcalcic garnets and their relation to diamond forming fluids—Case studies from Ekati (NWT-Canada) and Murowa (Zimbabwe)

    NASA Astrophysics Data System (ADS)

    Klein-BenDavid, Ofra; Graham Pearson, D.

    2009-02-01

    Subcalcic, high-Cr (G10) garnets are found as inclusions within diamonds and in peridotitic xenoliths. The strong spatial associations between G10 garnets and diamond make them an important tool in the investigation of diamond genesis. We present an integrated study of the major and trace element composition and oxygen-Sr-Nd-Hf isotopic ratios of eight G10 garnets from the Ekati mine (NWT-Canada) and four from the Murowa mine (Zimbabwe) in an attempt to determine their petrogenetic evolution and to further examine a possible relationship between the metasomatic agents responsible for G10 garnet signatures and diamond forming fluids. All garnets display sinusoidal to mildly sinusoidal REE patterns and have negative Ti, Sr and positive U anomalies. They have variably radiogenic 87Sr/ 86Sr (0.703261-0.731191) and non-radiogenic ɛNd values (-8.1 to -27.1), except for one sample from Murowa that has a positive ɛNd of 2.5. One Ekati sample has an extremely low ɛHf value of -61.6. The Ekati garnets we have studied all appear to come from a single depth in the Slave lithospheric mantle. On the base of Cr-Ca relations they have crystallized at 4.9 GPa and display dunitic Ca intercept values. Their δ 18O values range between +5.23‰ and +5.42‰. The Ekati G10 garnets record a complex, multi-stage metasomatic history involving the interaction of several components during their genesis. One metasomatic agent was enriched in HFSE, LREE, Sr, and depleted in Nb. This agent had the least radiogenic Sr. Another metasomatic agent had highly radiogenic Sr, and was enriched in LREE, Sr, Nb, Th and U. The G10 garnets have very low ɛNd and ɛHf values combined with radiogenic Sr, thus, they require an early lithospheric mantle enrichment event at some stage during their genesis or during the evolution of any precursor material that they formed from. The only Hf isotope composition measurable from the Ekati suite is so unradiogenic ( ɛHf = -61) that it yields a Lu/Hf model age of

  3. Cadmium and other elements in tissues from four ungulate species from the Mackenzie Mountain region of the Northwest Territories, Canada.

    PubMed

    Larter, N C; Macdonald, C R; Elkin, B T; Wang, X; Harms, N J; Gamberg, M; Muir, D C G

    2016-10-01

    Tissue samples from four ungulate species from the south Mackenzie Mountain region of the Northwest Territories (NT), Canada, were analysed for stable and radioactive elements and (15)N and (13)C stable isotopes. Elevated Cd concentrations in moose (Alces americanus) kidney have been observed in the region and are a health care concern for consumers of traditional foods. This study examined the factors associated with, and potential renal effects from, the accumulation of cadmium, and interactions with other elements in four sympatric ungulate species. Mean renal Cd concentration was highest in moose (48.3mg/kg ww), followed by mountain caribou (Rangifer tarandus caribou) (13.9mg/kg ww) and mountain goat (Oreamnos americanus) (5.78mg/kg ww). No local sources of Cd were evident and the elevated levels in moose are considered to be natural in origin. Conversely, total Hg concentration was significantly higher in mountain caribou kidney (0.21mg/kg ww) than in moose (0.011mg/kg ww). (134)Cs (t½=2.1 y) in mountain goat and Dall's sheep (Ovis dalli) muscle is evidence of deposition from the Fukushima reactor accident in 2011. (137)Cs (t½=30.2 y) in all four ungulates is primarily a remnant of the nuclear weapons tests of the 1960s. The levels of both nuclides are low and the risk to the animals and people consuming them is negligible. Stable isotope δ(15)N and δ(13)C signatures in muscle showed a separation between the mountain caribou, with a lichen-dominated diet, and moose, which browse shrubs and forbs. Isotope signatures for mountain goat and Dall's sheep showed generalist feeding patterns. Differences in elemental and radionuclide levels between species were attributed to relative levels of metal accumulation in the different food items in the diets of the respective species. Kidneys from each species showed minor histological changes in the proximal tubule and glomerulus, although glomerular changes were rare and all changes were rare in mountain goat kidney

  4. Cadmium and other elements in tissues from four ungulate species from the Mackenzie Mountain region of the Northwest Territories, Canada.

    PubMed

    Larter, N C; Macdonald, C R; Elkin, B T; Wang, X; Harms, N J; Gamberg, M; Muir, D C G

    2016-10-01

    Tissue samples from four ungulate species from the south Mackenzie Mountain region of the Northwest Territories (NT), Canada, were analysed for stable and radioactive elements and (15)N and (13)C stable isotopes. Elevated Cd concentrations in moose (Alces americanus) kidney have been observed in the region and are a health care concern for consumers of traditional foods. This study examined the factors associated with, and potential renal effects from, the accumulation of cadmium, and interactions with other elements in four sympatric ungulate species. Mean renal Cd concentration was highest in moose (48.3mg/kg ww), followed by mountain caribou (Rangifer tarandus caribou) (13.9mg/kg ww) and mountain goat (Oreamnos americanus) (5.78mg/kg ww). No local sources of Cd were evident and the elevated levels in moose are considered to be natural in origin. Conversely, total Hg concentration was significantly higher in mountain caribou kidney (0.21mg/kg ww) than in moose (0.011mg/kg ww). (134)Cs (t½=2.1 y) in mountain goat and Dall's sheep (Ovis dalli) muscle is evidence of deposition from the Fukushima reactor accident in 2011. (137)Cs (t½=30.2 y) in all four ungulates is primarily a remnant of the nuclear weapons tests of the 1960s. The levels of both nuclides are low and the risk to the animals and people consuming them is negligible. Stable isotope δ(15)N and δ(13)C signatures in muscle showed a separation between the mountain caribou, with a lichen-dominated diet, and moose, which browse shrubs and forbs. Isotope signatures for mountain goat and Dall's sheep showed generalist feeding patterns. Differences in elemental and radionuclide levels between species were attributed to relative levels of metal accumulation in the different food items in the diets of the respective species. Kidneys from each species showed minor histological changes in the proximal tubule and glomerulus, although glomerular changes were rare and all changes were rare in mountain goat kidney

  5. The Beaver River structure: A cross-strike discontinuity of possible crustal dimensions in the southern Mackenzie Fold Belt, Yukon and Northwest territories, Canada

    USGS Publications Warehouse

    Morrow, D.W.; Miles, W.C.

    2000-01-01

    A significant cross-strike structural discontinuity, the Beaver River Structure, has been recognized near the boundary between the north-central part of the Mackenzie Fold Belt and its southern part, the Liard Plateau. The Beaver River Structure is the northeast continuation of the Beaver Fault toward the confluence of the South Nahanni and Liard rivers and into the Interior Platform. It is oriented sub-parallel with the Liard Line farther south. Cumulative Laramide-aged dextral movement of 10 to 20 kilometres is inferred to have occurred along the Beaver River Structure. Small dextral offsets occur along the Beaver Fault, a possible surface manifestation of the Beaver River Structure and large, dominantly north-south oriented Laramide-aged folds and faults, such as the Kotaneelee and Liard synclines and the Nahanni Thrust Fault appear to have been locally rotated in a manner consistent with dextral strike-slip of at least 10 to 20 kilometres. The absence of Permian and Triassic strata in the Mackenzie Fold Belt north of the Beaver River Structure may indicate that uplift and erosion occurred north of the Beaver River Structure during the Early Cretaceous Columbian Orogeny. It is likely that the Beaver River Structure is an ancient, possibly Precambrian, structure that has been reactivated several times throughout Phanerozoic time.

  6. DELTA PHASE PLUTONIUM ALLOYS

    DOEpatents

    Cramer, E.M.; Ellinger, F.H.; Land. C.C.

    1960-03-22

    Delta-phase plutonium alloys were developed suitable for use as reactor fuels. The alloys consist of from 1 to 4 at.% zinc and the balance plutonium. The alloys have good neutronic, corrosion, and fabrication characteristics snd possess good dimensional characteristics throughout an operating temperature range from 300 to 490 deg C.

  7. The Devil's in the Delta

    ERIC Educational Resources Information Center

    Luyben, William L.

    2007-01-01

    Students frequently confuse and incorrectly apply the several "deltas" that are used in chemical engineering. The deltas come in three different flavors: "out minus in", "big minus little" and "now versus then." The first applies to a change in a stream property as the stream flows through a process. For example, the "[delta]H" in an energy…

  8. Delta-ALA urine test

    MedlinePlus

    Delta-aminolevulinic acid ... This test looks for an increased level of delta-ALA. It may be used to help diagnose ... An increased level of urinary delta-ALA may indicate: Lead poisoning ... level may occur with chronic (long-term) liver disease .

  9. DELTAS: A new Global Delta Sustainability Initiative (Invited)

    NASA Astrophysics Data System (ADS)

    Foufoula-Georgiou, E.

    2013-12-01

    Deltas are economic and environmental hotspots, food baskets for many nations, home to a large part of the world population, and hosts of exceptional biodiversity and rich ecosystems. Deltas, being at the land-water interface, are international, regional, and local transport hubs, thus providing the basis for intense economic activities. Yet, deltas are deteriorating at an alarming rate as 'victims' of human actions (e.g. water and sediment reduction due to upstream basin development), climatic impacts (e.g. sea level rise and flooding from rivers and intense tropical storms), and local exploration (e.g. sand or aggregates, groundwater and hydrocarbon extraction). Although many efforts exist on individual deltas around the world, a comprehensive global delta sustainability initiative that promotes awareness, science integration, data and knowledge sharing, and development of decision support tools for an effective dialogue between scientists, managers and policy makers is lacking. Recently, the international scientific community proposed to establish the International Year of Deltas (IYD) to serve as the beginning of such a Global Delta Sustainability Initiative. The IYD was proposed as a year to: (1) increase awareness and attention to the value and vulnerability of deltas worldwide; (2) promote and enhance international and regional cooperation at the scientific, policy, and stakeholder level; and (3) serve as a launching pad for a 10-year committed effort to understand deltas as complex socio-ecological systems and ensure preparedness in protecting and restoring them in a rapidly changing environment. In this talk, the vision for such an international coordinated effort on delta sustainability will be presented as developed by a large number of international experts and recently funded through the Belmont Forum International Opportunities Fund. Participating countries include: U.S., France, Germany, U.K., India, Japan, Netherlands, Norway, Brazil, Bangladesh

  10. Understanding pesticides in California's Delta

    USGS Publications Warehouse

    Kuivila, Kathryn M.; Orlando, James L.

    2012-01-01

    The Sacramento-San Joaquin River Delta (Delta) is the hub of California’s water system and also an important habitat for imperiled fish and wildlife. Aquatic organisms are exposed to mixtures of pesticides that flow through the maze of Delta water channels from sources including agricultural, landscape, and urban pest-control applications. While we do not know all of the effects pesticides have on the ecosystem, there is evidence that they cause some damage to organisms in the Delta. Decades of USGS research have provided a good understanding of when, where, and how pesticides enter the Delta. However, pesticide use is continually changing. New field studies and methods are needed so that scientists can analyze which pesticides are present in the Delta, and at what concentrations, enabling them to estimate exposure and ultimate effects on organisms. Continuing research will provide resource managers and stakeholders with crucial information to manage the Delta wisely.

  11. The Changing Cold Regions Network: Atmospheric, Cryospheric, Ecological and Hydrological Change in the Saskatchewan and Mackenzie River Basins, Canada (Invited)

    NASA Astrophysics Data System (ADS)

    Wheater, H. S.; DeBeer, C.

    2013-12-01

    The cold interior of Northwestern Canada has one of the world's most extreme and varied climates and, as with other regions across the Arctic, is experiencing rapid environmental change. The Changing Cold Regions Network (CCRN) is a new Canadian research network devoted to addressing key challenges and globally-important issues facing the Arctic by improving the understanding of past and ongoing changes in climate, land, vegetation, and water, and predicting their future integrated responses, with a geographic focus on the Saskatchewan and Mackenzie River Basins. The network is funded for 5 years (2013-18) by the Natural Sciences and Engineering Research Council of Canada, and combines the unique expertise of 36 Canadian scientists representing 8 universities and 4 Federal government agencies, as well as 15 international researchers from the United States, China, Australia, the UK, France, and Germany. The network will also involve the World Climate Research Programme, NASA, the Canadian Space Agency, and the National Center for Atmospheric Research. CCRN will integrate existing and new experimental data with modelling and remote sensing products to understand, diagnose and predict changing land, water and climate, and their interactions and feedbacks, for Northwestern Canada's cold interior. It will use a network of world class observatories to study the detailed connections among changing climate, ecosystems and water in the permafrost regions of the Sub-arctic, the Boreal Forest, the Western Cordillera, and the Prairies. Specifically, the network will: 1. Document and evaluate observed Earth system change, including hydrological, ecological, cryospheric and atmospheric components over a range of scales from local observatories to biome and regional scales; 2. Improve understanding and diagnosis of local-scale change by developing new and integrative knowledge of Earth system processes, incorporating these processes into a suite of process-based integrative

  12. Late Pleistocene ice margin fluctuations in the Nahanni National Park-UNESCO World Heritage Site and their impact on glacial lake formation and architecture of drainage systems across the Yukon-NWT continental divide

    NASA Astrophysics Data System (ADS)

    Duk-Rodkin, A.; Barendregt, R. W.

    2009-12-01

    In the late Pleistocene the southern Mackenzie region was glaciated by ice masses from a Cordilleran and continental source (Laurentide). Stratigraphic and geomorphologic evidence indicate that the two glaciers occupied this region at different times during the Late Pleistocene. The continental ice sheet advanced over the foothills and up major valleys reaching its maximum extent, ca. 30 ka. B. P. This took place when Cordilleran glaciers were in their initial stages of development. The Laurentide Ice Sheet blocked the drainage of the South Nahanni River near Virginia Falls, forming a glacial lake which inundated an area of approximately 900 km2 at its maximum stand, and had an outlet to the southwest, across the continental divide into the Yukon Territory and eventually into the Pacific Ocean. Lacustrine sediments at various sites reach thicknesses ranging from 110 to 120 metres, at an elevation of around 700 m. Cordilleran glaciers advanced eastward and approximately 5000 years later blocked this southwestward drainage, rerouting it to the east and north along the Mackenzie Mountain front. The drainage was confined between the mountains and continental ice margin where it incised major canyons into the limestone bedrock, and produced a spectacular karst landscape, which today forms part of the Nahanni National Park. During the retreat of the Laurentide and advance of Cordilleran glaciers, glacial Lake Nahanni cut an outlet to the east at First Canyon. This outlet drained into a continuous northbound network of marginal meltwater channels joining the north-flowing drainage that eventually reached the Arctic Ocean, and during further retreat of the ice sheet established the Mackenzie River in its modern location. The presence of Laurentide ice in this region is evidenced by large granite boulders carried from the Canadian Shield. Erratics are found up to 100 km west of the mountain front. Neotectonic activity in the area is interpreted from exposures such as those

  13. Mississippi River Delta

    NASA Technical Reports Server (NTRS)

    2002-01-01

    As the Mississippi River enters the Gulf of Mexico, it loses energy and dumps its load of sediment that it has carried on its journey through the mid continent. This pile of sediment, or mud, accumulates over the years building up the delta front. As one part of the delta becomes clogged with sediment, the delta front will migrate in search of new areas to grow. The area shown on this image is the currently active delta front of the Mississippi. The migratory nature of the delta forms natural traps for oil. Most of the land in the image consists of mud flats and marsh lands. There is little human settlement in this area due to the instability of the sediments. The main shipping channel of the Mississippi River is the broad stripe running northwest to southeast.

    This image was acquired on May 24, 2001 by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite. With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER will image Earth for the next 6 years to map and monitor the changing surface of our planet.

    ASTER is one of five Earth-observing instruments launched December 18,1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, California, is the U.S. Science team leader; Bjorn Eng of JPL is the project manager. The Terra mission is part of NASA's Earth Science Enterprise, a long-term research and technology program designed to examine Earth's land, oceans, atmosphere, ice and life as a total integrated system.

    The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for surface mapping

  14. The influence of the Mackenzie River plume on distribution and diversity of marine larval fish assemblages on the Canadian Beaufort Shelf

    NASA Astrophysics Data System (ADS)

    Wong, Sally; Walkusz, Wojciech; Hanson, Mark; Papst, Michael H.

    2013-11-01

    In the Beaufort Sea, freshwater input from the Mackenzie River creates a relatively warm and turbid plume across the coastal shelf region. To determine the influence of this plume on marine larval fish abundance, distribution, and assemblages, we sampled larval fish during July and August of 2007 using 500 μm bongo nets on transects across the plume gradient at three sampling stations per transect, along with oceanographic measurements. Three larval fish assemblages were identified within three distinct oceanographic zones: intense plume, diffuse plume and oceanic. The intense plume assemblage was dominated by Saffron cod (Eleginus gracilis) and Pacific herring (Clupea pallasii); the diffuse plume assemblage was dominated by the Pricklebacks (sub-family Lumpeninae); and the oceanic assemblage was dominated by Arctic cod (Boreogadus saida). Even though there were differences in relative abundance of particular species among these areas, no significant differences in total abundances of larval fish were found.

  15. Zircon (U-Th)/He thermochronology of Neoproterozoic strata from the Mackenzie Mountains, Canada: Implications for the Phanerozoic exhumation and deformation history of the northern Canadian Cordillera

    NASA Astrophysics Data System (ADS)

    Powell, Jeremy; Schneider, David; Stockli, Daniel; Fallas, Karen

    2016-03-01

    Sedimentary strata of the Neoproterozoic Mackenzie Mountains Supergroup (MMSG) and Windermere Supergroup (WSG) occupy the cores of anticlines in the Mackenzie Mountains of the Canadian Cordilleran Foreland Belt. Stratigraphic and structural evidence suggest that these rocks have undergone several episodes of burial and unroofing relatively intact. We report single-grain detrital muscovite 40Ar/39Ar and zircon (U-Th)/He (ZHe) data from a suite of samples across the fold-thrust belt and the Neoproterozoic stratigraphic record. The strata have not reached high enough temperatures to reset the muscovite 40Ar/39Ar system, and instead our detrital muscovite data refine Tonian-Cryogenian depositional ages. Single-crystal ZHe dates range from 432 ± 35 to 46 ± 4 Ma, indicating that MMSG and WSG strata have not been heated sufficiently to fully reset the ZHe system. These factors make the Neoproterozoic strata an attractive natural laboratory to test the utility of the zircon radiation damage and annealing model on the quantification of thermal histories from detrital zircon populations that have accumulated radiation damage over long geologic timescales. Thermal modeling reveals that (1) a substantial sedimentary package was deposited following the Devonian and removed during Permo-Triassic cooling, and (2) the Cordilleran deformation front propagated through the study area from the Albian to the Paleocene, with a moderate increase in cooling rates between 75-67 Ma in the southwest and 60-55 Ma at the deformation front. Ultimately, relationships between radiation damage and helium diffusion kinetics in zircon explain substantial ZHe date dispersion and elucidate the temperature-time history of the northern Canadian Cordillera.

  16. Natural processes in delta restoration: application to the Mississippi Delta.

    PubMed

    Paola, Chris; Twilley, Robert R; Edmonds, Douglas A; Kim, Wonsuck; Mohrig, David; Parker, Gary; Viparelli, Enrica; Voller, Vaughan R

    2011-01-01

    Restoration of river deltas involves diverting sediment and water from major channels into adjoining drowned areas, where the sediment can build new land and provide a platform for regenerating wetland ecosystems. Except for local engineered structures at the points of diversion, restoration mainly relies on natural delta-building processes. Present understanding of such processes is sufficient to provide a basis for determining the feasibility of restoration projects through quantitative estimates of land-building rates and sustainable wetland area under different scenarios of sediment supply, subsidence, and sea-level rise. We are not yet to the point of being able to predict the evolution of a restored delta in detail. Predictions of delta evolution are based on field studies of active deltas, deltas in mine-tailings ponds, experimental deltas, and countless natural experiments contained in the stratigraphic record. These studies provide input for a variety of mechanistic delta models, ranging from radially averaged formulations to more detailed models that can resolve channels, topography, and ecosystem processes. Especially exciting areas for future research include understanding the mechanisms by which deltaic channel networks self-organize, grow, and distribute sediment and nutrients over the delta surface and coupling these to ecosystem processes, especially the interplay of topography, network geometry, and ecosystem dynamics. PMID:21329199

  17. Pioneer Launch on Delta Vehicle

    NASA Technical Reports Server (NTRS)

    1969-01-01

    NASA launches the last in the series of interplanetary Pioneer spacecraft, Pioneer 10 from Cape Kennedy, Florida. The long-tank Delta launch vehicle placed the spacecraft in a solar orbit along the path of Earth's orbit. The spacecraft then passed inside and outside Earth's orbit, alternately speeding up and slowing down relative to Earth. The Delta launch vehicle family started development in 1959. The Delta was composed of parts from the Thor, an intermediate-range ballistic missile, as its first stage, and the Vanguard as its second. The first Delta was launched from Cape Canaveral on May 13, 1960 and was powerful enough to deliver a 100-pound spacecraft into geostationary transfer orbit. Delta has been used to launch civil, commercial, and military satellites into orbit. For more information about Delta, please see Chapter 3 in Roger Launius and Dennis Jenkins' book To Reach the High Frontier published by The University Press of Kentucky in 2002.

  18. Delta in Eberswalde

    NASA Technical Reports Server (NTRS)

    2006-01-01

    This HiRISE image covers a portion of a delta that partially fills Eberswalde crater in Margaritifer Sinus. The delta was first recognized and mapped using MOC images that revealed various features whose presence required sustained flow and deposition into a lake that once occupied the crater. The HiRISE image resolves meter-scale features that record the migration of channels and delta distributaries as the delta grew over time. Differences in grain-size of sediments within the environments on the delta enable differential erosion of the deposits. As a result, coarser channel deposits are slightly more resistant and stand in relief relative to finer-grained over-bank and more easily eroded distal delta deposits. Close examination of the relict channel deposits confirms the presence of some meter-size blocks that were likely too coarse to have been transported by water flowing within the channels. These blocks may be formed of the sand and gravel that more likely moved along the channels that was lithified and eroded. Numerous meter-scale polygonal structures are common on many surfaces, but mostly those associated with more quiescent depositional environments removed from the channels. The polygons could be the result of deposition of fine-grained sediments that were either exposed and desiccated (dried out), rich in clays that shrunk when the water was removed, turned into rock and then fractured and eroded, or some combination of these processes.

    Image PSP_001336_1560 was taken by the High Resolution Imaging Science Experiment (HiRISE) camera onboard the Mars Reconnaissance Orbiter spacecraft on November 8, 2006. The complete image is centered at -23.8 degrees latitude, 326.4 degrees East longitude. The range to the target site was 256.3 km (160.2 miles). At this distance the image scale is 25.6 cm/pixel (with 1 x 1 binning) so objects 77 cm across are resolved. The image shown here has been map-projected to 25 cm/pixel and north is up. The image was

  19. Delta II commercial space transportation

    NASA Astrophysics Data System (ADS)

    Meyers, J. F.

    1988-07-01

    Delta II is an upgraded variant of the Delta family of launch vehicles that has been in use by NASA since 1960. Among the design improvements incorporated by Delta II is a cryogenic-propellant second stage, a 2.89-m diameter satellite-protecting nose fairing, graphite/epoxy solid rocket motor cases, and 12:1 main engine expansion nozzle. The manufacturer/operator offers Delta II customers a dedicated, single satellite launch capability fully tailored to the given spacecraft's unique mission requirements.

  20. Shanghai Delta Complex

    SciTech Connect

    Hart, R.E.; Hoffman, P.F.; Parker, R.W.

    1988-01-01

    The upper Eocene Yegua Formation expands dramatically across a regional system of growth faults into an area generally 12-15 km wide, extending at least from the western edge of the Houston sale dome basin to the San Marcos arch. Within this area, the expanded Yegua trend has yielded, since 1982, at least seven noteworthy discoveries: Toro Grande and Lost Bridge fields in Jackson County, and Black Owl, Shanghai, Shanghai East, El Campo, and Phase Four fields in Wharton County. During each of several postulated Yegua sea level drops, this flexure became a focal point for deltaic deposition of excellent reservoir-quality sands. Shanghai, Shanghai East, and El Campo fields are located within what the writers have labeled the ''Shanghai delta complex.'' Integration of seismic and well data in this vicinity shows a marked increase in the expansion indices of growth faults, and moderately thick progradational sand sequences have accumulated immediately downthrow. This structural-stratigraphic pattern, as well as internal bedding characteristics and other lithologic data observed, is believed typical of deltas deposited along the Yegua shelf margin.

  1. Holden Crater Delta

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Context image for PIA03694 Holden Crater Delta

    This fan-shaped delta deposit is located in Holden Crater.

    Image information: VIS instrument. Latitude -27.3N, Longitude 324.5E. 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  2. Delta Electroproduction in 12-C

    SciTech Connect

    Steven McLauchlan

    2003-01-31

    The Delta-nucleus potential is a crucial element in the understanding of the nuclear system. Previous electroexcitation measurements in the delta region reported a Q2 dependence of the delta mass indicating that this potential is dependent on the momentum of the delta. Such a dependence is not observed for protons and neutrons in the nuclear medium. This thesis presents the experimental study of the electroexcitation of the delta resonance in 12C, performed using the high energy electron beam at the Thomas Jefferson National Accelerator Facility, and the near 4(pie) acceptance detector CLAS that enables the detection of the full reaction final state. Inclusive, semi inclusive, and exclusive cross sections were measured with an incident electron beam energy of 1.162GeV over the Q2 range 0.175-0.475 (GeV/c)2. A Q2 dependence of the delta mass was only observed in the exclusive measurements indicating that the delta-nucleus potential is affected by the momentum of the delta.

  3. Highly siderophile element behaviour during flood basalt genesis and evidence for melts from intrusive chromitite formation in the Mackenzie large igneous province

    NASA Astrophysics Data System (ADS)

    Day, James M. D.; Pearson, D. Graham; Hulbert, Larry J.

    2013-12-01

    The 1.27 Ga Coppermine continental flood basalt (CFB) province in northern Canada represents the extrusive manifestation of the 2.7 Mkm2 Mackenzie large igneous province (LIP) that includes the Mackenzie dyke swarm and the Muskox layered intrusion. New Re-Os isotope and highly siderophile element (HSE: Re, Pd, Pt, Ru, Ir, Os) abundance data are reported together with whole-rock major- and trace-element abundances and Nd isotopes to examine the behaviour of the HSE during magmatic differentiation and to place constraints on the extent of crustal interaction with mantle-derived melts. Mineral chemistry and petrography are also reported for an unusual andesite glass flow (CM19; 4.9 wt.% MgO) found in close proximity to newly recognised picrites (> 20 wt.% MgO) in the lowermost stratigraphy of the Coppermine CFB. Compositions of mineral phases in CM19 are similar to the same phases found in Muskox Intrusion chromitites and the melt composition is equivalent to inclusions trapped within Muskox chromites. The apparently conflicting elevated HSE contents (e.g., 3.8 ppb Os) and mantle-like initial 187Os/188Os (γOs = + 2.2), versus stable isotope (δ18O = + 12‰) and lithophile element evidence (εNdi = - 12.8) for extensive crustal contamination, implicate an origin for CM19 as a magma mingling product formed within the Muskox Intrusion during chromitite genesis. Combined with Nd isotope data that places the feeder for lower Coppermine CFB picrites and basalts within the Muskox Intrusion, this result provides compelling evidence for direct processing of some CFB within upper-crustal magma chambers. The Coppermine CFB defines a 187Re-187Os isochron with an age of 1263 + 16/- 20 Ma and initial γOs = + 2.2 ± 0.8. The initial Os isotope composition for the Coppermine CFB is slightly higher than the near-primitive-mantle initial 187Os/188Os for the Muskox Intrusion (γOs = + 1.2 ± 0.3). This result is interpreted to reflect greater crustal contamination in extrusive CFB

  4. Artificial delta growth

    NASA Astrophysics Data System (ADS)

    Mikeš, Daniel

    2010-05-01

    A deltaic sedimentary system has a point source; sediment is carried over the delta plain by distributary channels away from the point source and deposited at the delta front by distributary mouth bars. The established methods to describe such a sedimentary system are "bedding analysis", "facies analysis", and "basin analysis". We shall call the ambient conditions "input" and the rock record "output". There exist a number of methods to deduce input from output, e.g. "Sequence stratigraphy" (a.o. Vail et al. 1977, Catuneanu et al. 2009), "Shoreline trajectory" (a.o. Helland-Hansen & Martinsen 1996, Helland-Hansen & Hampson 2009) on the one hand and the complex use of established techniques on the other (a.o. Miall & Miall 2001, Miall & Miall 2002). None of these deductive methods seems to be sufficient. I claim that the common errors in all these attempts are the following: (1) a sedimentary system is four-dimensional (3+1) and a lesser dimensional analysis is insufficient; (2) a sedimentary system is complex and any empirical/deductive analysis is non-unique. The proper approach to the problem is therefore the theoretical/inductive analysis. To that end we performed six scenarios of a scaled version of a passive margin delta in a flume tank. The scenarios have identical stepwise tectonic subsidence and semi-cyclic sealevel, but different supply curves, i.e. supply is: constant, highly-frequent, proportional to sealevel, inversely proportional to sealevel, lagging to sealevel, ahead of sealevel. The preliminary results are indicative. Lobe-switching occurs frequently and hence locally sedimentation occurs shortly and hiatuses are substantial; therefore events in 2D (+1) cross-sections don't correlate temporally. The number of sedimentary cycles disequals the number of sealevel cycles. Lobe-switching and stepwise tectonic subsidence cause onlap/transgression. Erosional unconformities are local diachronous events, whereas maximum flooding surfaces are regional

  5. The Mackenzie River magnetic anomaly, Yukon and Northwest Territories, Canada-Evidence for Early Proterozoic magmatic arc crust at the edge of the North American craton

    USGS Publications Warehouse

    Pilkington, M.; Saltus, R.W.

    2009-01-01

    We characterize the nature of the source of the high-amplitude, long-wavelength, Mackenzie River magnetic anomaly (MRA), Yukon and Northwest Territories, Canada, based on magnetic field data collected at three different altitudes: 300??m, 3.5??km and 400??km. The MRA is the largest amplitude (13??nT) satellite magnetic anomaly over Canada. Within the extent of the MRA, source depth estimates (8-12??km) from Euler deconvolution of low-altitude aeromagnetic data show coincidence with basement depths interpreted from reflection seismic data. Inversion of high-altitude (3.5??km) aeromagnetic data produces an average magnetization of 2.5??A/m within a 15- to 35-km deep layer, a value typical of magmatic arc complexes. Early Proterozoic magmatic arc rocks have been sampled to the southeast of the MRA, within the Fort Simpson magnetic anomaly. The MRA is one of several broad-scale magnetic highs that occur along the inboard margin of the Cordillera in Canada and Alaska, which are coincident with geometric changes in the thrust front transition from the mobile belt to stable cratonic North America. The inferred early Proterozoic magmatic arc complex along the western edge of the North American craton likely influenced later tectonic evolution, by acting as a buttress along the inboard margin of the Cordilleran fold-and-thrust belt. Crown Copyright ?? 2008.

  6. Understanding Nearshore Processes Of a Large Arctic Delta Using Combined Seabed Mapping, In Situ Observations, Remote Sensing and Modeling

    NASA Astrophysics Data System (ADS)

    Solomon, S. M.; Couture, N. J.; Forbes, D. L.; Hoque, A.; Jenner, K. A.; Lintern, G.; Mulligan, R. P.; Perrie, W. A.; Stevens, C. W.; Toulany, B.; Whalen, D.

    2009-12-01

    The Mackenzie River Delta and the adjacent continental shelf in the southeastern Beaufort Sea are known to host significant quantities of hydrocarbons. Recent environmental reviews of proposed hydrocarbon development have highlighted the need for a better understanding of the processes that control sediment transport and coastal stability. Over the past several years field surveys have been undertaken in winter, spring and summer to acquire data on seabed morphology, sediment properties, sea ice, river-ocean interaction and nearshore oceanography. These data are being used to improve conceptual models of nearshore processes and to develop and validate numerical models of waves, circulation and sediment transport. The timing and location of sediment erosion, transport and deposition is complex, driven by a combination of open water season storms and spring floods. Unlike temperate counterparts, the interaction between the Mackenzie River and the Beaufort Sea during spring freshet is mediated by the presence of ice cover. Increasing discharge exceeds the under-ice flow capacity leading to flooding of the ice surface, followed by vortex drainage through the ice and scour of the seabed below (“strudel” drainage and scour). During winter months, nearshore circulation slows beneath a thickening ice canopy. Recent surveys have shown that the low gradient inner shelf is composed of extensive shoals where ice freezes to the seabed and intervening zones which are slightly deeper than the ice is thick. The duration of ice contact with the bed determines the thermal characteristics of the seabed. Analysis of cores shows that the silts comprising the shoals are up to 6 m thick. The predominantly well sorted and cross-laminated nature of the silts at the top of the cores suggests an active delta front environment. Measurements of waves, currents, conductivity, temperature and sediment concentration during spring and late summer have been acquired. During moderate August

  7. The DELTA Synchrotron Light Interferometer

    SciTech Connect

    Berges, U.

    2004-05-12

    Synchrotron radiation sources like DELTA, the Dortmund Electron Accelerator, a third generation synchrotron light source, need an optical monitoring system to measure the beam size at different points of the ring with high resolution and accuracy. These measurements also allow an investigation of the emittance of the storage ring, an important working parameter for the efficiency of working beamlines with experiments using the synchrotron radiation. The resolution limits of the different types of optical synchrotron light monitors at DELTA are investigated. The minimum measurable beamsize with the normal synchrotron light monitor using visible light at DELTA is about 80 {mu}m. Due to this a synchrotron light interferometer was built up and tested at DELTA. The interferometer uses the same beamline in the visible range. The minimum measurable beamsize is with about 8 {mu}m one order of magnitude smaller. This resolution is sufficient for the expected small vertical beamsizes at DELTA. The electron beamsize and emittance were measured with both systems at different electron beam energies of the storage ring. The theoretical values of the present optics are smaller than the measured emittance. So possible reasons for beam movements are investigated.

  8. Spatial variability of particle-attached and free-living bacterial diversity in surface waters from the Mackenzie River to the Beaufort Sea (Canadian Arctic)

    NASA Astrophysics Data System (ADS)

    Ortega-Retuerta, E.; Joux, F.; Jeffrey, W. H.; Ghiglione, J. F.

    2013-04-01

    We explored the patterns of total and active bacterial community structure in a gradient covering surface waters from the Mackenzie River to the coastal Beaufort Sea in the Canadian Arctic Ocean, with a particular focus on free-living (FL) vs. particle-attached (PA) communities. Capillary electrophoresis-single-strand conformation polymorphism (CE-SSCP) showed significant differences when comparing river, coast and open sea bacterial community structures. In contrast to the river and coastal waters, total (16S rDNA-based) and active (16S rRNA-based) communities in the open sea samples were not significantly different, suggesting that most present bacterial groups were equally active in this area. Additionally, we observed significant differences between PA and FL bacterial community structure in the open sea, but similar structure in the two fractions for coastal and river samples. Direct multivariate statistical analyses showed that total community structure was mainly driven by salinity (a proxy of dissolved organic carbon and chromophoric dissolved organic matter), suspended particles, amino acids and chlorophyll a. Pyrosequencing of 16S rRNA genes from selected samples confirmed significant differences between river, coastal and sea samples. The PA fraction was only different (15.7% similarity) from the FL one in the open sea sample. Furthermore, PA samples generally showed higher diversity (Shannon, Simpson and Chao indices) than FL samples. At the class level, Opitutae was most abundant in the PA fraction of the sea sample, followed by Flavobacteria and Gammaproteobacteria, while the FL sea sample was dominated by Alphaproteobacteria. Finally, for the coast and river samples and both PA and FL fractions, Betaproteobacteria, Alphaproteobacteria and Actinobacteria were dominant. These results highlight the coexistence of particle specialists and generalists and the role of particle quality in structuring bacterial communities in the area. These results may also

  9. Spatial variability of particle-attached and free-living bacterial diversity in surface waters from the Mackenzie River to the Beaufort Sea (Canadian Arctic)

    NASA Astrophysics Data System (ADS)

    Ortega-Retuerta, E.; Joux, F.; Jeffrey, W. H.; Ghiglione, J.-F.

    2012-12-01

    We explored the patterns of total and active bacterial community structure in a gradient covering surface waters from the Mackenzie River to the coastal Beaufort Sea, Canadian Arctic Ocean, with a particular focus on free-living vs. particle-attached communities. Capillary electrophoresis-single strand conformation polymorphism (CE-SSCP) showed significant differences when comparing river, coast and open sea bacterial community structures. In contrast to the river and coastal waters, total (16S rDNA-based) and active (16S rRNA-based) communities in the open sea samples were not significantly different, suggesting that most present bacterial groups were equally active in this area. Additionally, we observed significant differences between particle-attached (PA) and free-living (FL) bacterial communities in the open sea, but similar structure in the two fractions for coastal and river samples. Direct multivariate statistical analyses showed that total community structure was mainly driven by salinity (proxy of DOC and CDOM), suspended particles, amino acids and chlorophyll a. 16S rRNA genes pyrosequencing of selected samples confirmed these significant differences from river to sea and also between PA and FL fractions only in open sea samples, and PA samples generally showed higher diversity (Shannon, Simpson and Chao indices) than FL samples. At the class level, Opitutae was most abundant in the PA fraction of the sea sample, followed by Flavobacteria and Gammaproteobacteria, while the FL sea sample was dominated by Alphaproteobacteria. Finally, the coast and river samples, both PA and FL fractions, were dominated by Betaproteobacteria, Alphaproteobacteria and Actinobacteria. These results highlight the coexistence of particle specialists and generalists and the role of particle quality in structuring bacterial communities in the area. These results may also serve as a~basis to predict further changes in bacterial communities should climate change lead to further

  10. The Changing Cold Regions Network: Improving the Understanding and Prediction of Changing Land, Water, and Climate in the Mackenzie and Saskatchewan River Basins, Canada

    NASA Astrophysics Data System (ADS)

    DeBeer, C. M.; Wheater, H. S.; Chun, K. P.; Shook, K.; Whitfield, P. H.

    2014-12-01

    Within the cold interior of western and northern Canada, rapid and widespread environmental changes are taking place, which are of serious concern for society and have a range of implications from local to regional and global scales. From a scientific standpoint there is an urgent need to understand the changes and develop improved diagnostic and predictive modelling tools to deal with the uncertainty faced in the future. The Changing Cold Regions Network (CCRN) is a research consortium of over 50 Canadian university and government scientists and international researchers aimed at addressing these issues within the geographic domain of the Mackenzie and Saskatchewan River Basins. CCRN's primary focus is to integrate existing and new experimental data with modelling and remote sensing products to understand, diagnose and predict changing land, water and climate, and their interactions and feedbacks. To support these activities, the network utilizes a suite of 14 world-class water, ecosystem, cryosphere and climate (WECC) observatories across this region that provide exceptional opportunities to observe change, investigate processes and their dynamics, and develop and test environmental models. This talk will briefly describe the CCRN thematic components and WECC observatories, and will then describe some of the observed environmental changes and their linkages across the northern and mountainous parts of the network study domain. In particular, this will include changes in permafrost, terrestrial vegetation, snowcover, glaciers, and river discharge in relation to observed climatic changes across the region. The observations draw on a wide range of literature sources and statistical analyses of federal and provincial regional monitoring network data, while more detailed observations at some of the WECC observatories help to show how these regional changes are manifested at local scales and vice versa. A coordinated special observation and analysis period across all

  11. Delta launch vehicle inertial guidance system (DIGS)

    NASA Technical Reports Server (NTRS)

    Duck, K. I.

    1973-01-01

    The Delta inertial guidance system, part of the Delta launch vehicle improvement effort, has been flown on three launches and was found to perform as expected for a variety of mission profiles and vehicle configurations.

  12. Delta nitrogen tetroxide fueling operations

    NASA Technical Reports Server (NTRS)

    Grigsby, R. B.; Cross, T. M.; Rucci, T. D.

    1978-01-01

    The development of the Delta second stage nitrogen tetroxide fueling system is briefly summarized. The nitrogen tetroxide fueling system and the equipment used to protect the spacecraft environment from the toxic nitrogen tetroxide fumes are described. Topics covered include: the nitrogen tetroxide transfer system; loading operations; safety precautions; and chemical treatment of all toxic vapors.

  13. Spongeplant Spreading in the Delta

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Invasive, exotic aquatic plants impact a range of important economic and ecological functions in the Sacramento-San Joaquin Delta of California, and the state now spends over $5 million to control water hyacinth and Brazilian waterweed. In 2007, a new exotic floating plant South American Spongeplan...

  14. Delta launch vehicle accident investigation

    NASA Astrophysics Data System (ADS)

    1986-03-01

    The text of the testimony given by several witnesses during the House hearings on the Delta launch vehicle accident of May 3, 1986 is given. Pre-launch procedures, failure analysis, the possibility of sabotage, and design and testing are among the topics discussed.

  15. N-{Delta} weak transition

    SciTech Connect

    Graczyk, Krzysztof M.

    2011-11-23

    A short review of the Rein-Sehgal and isobar models is presented. The attention is focused on the nucleon-{Delta}(1232) weak transition form-factors. The results of the recent re-analyses of the ANL and BNL bubble chamber neutrino-deuteron scattering data are discussed.

  16. Phytoplankton fuels Delta food web

    USGS Publications Warehouse

    Jassby, Alan D.; Cloern, James E.; Muller-Solger, A. B.

    2003-01-01

    Populations of certain fishes and invertebrates in the Sacramento-San Joaquin Delta have declined in abundance in recent decades and there is evidence that food supply is partly responsible. While many sources of organic matter in the Delta could be supporting fish populations indirectly through the food web (including aquatic vegetation and decaying organic matter from agricultural drainage), a careful accounting shows that phytoplankton is the dominant food source. Phytoplankton, communities of microscopic free-floating algae, are the most important food source on a Delta-wide scale when both food quantity and quality are taken into account. These microscopic algae have declined since the late 1960s. Fertilizer and pesticide runoff do not appear to be playing a direct role in long-term phytoplankton changes; rather, species invasions, increasing water transparency and fluctuations in water transport are responsible. Although the potential toxicity of herbicides and pesticides to plank- ton in the Delta is well documented, the ecological significance remains speculative. Nutrient inputs from agricultural runoff at current levels, in combination with increasing transparency, could result in harmful al- gal blooms. 

  17. Revisiting double Dirac delta potential

    NASA Astrophysics Data System (ADS)

    Ahmed, Zafar; Kumar, Sachin; Sharma, Mayank; Sharma, Vibhu

    2016-07-01

    We study a general double Dirac delta potential to show that this is the simplest yet still versatile solvable potential to introduce double wells, avoided crossings, resonances and perfect transmission (T = 1). Perfect transmission energies turn out to be the critical property of symmetric and anti-symmetric cases wherein these discrete energies are found to correspond to the eigenvalues of a Dirac delta potential placed symmetrically between two rigid walls. For well(s) or barrier(s), perfect transmission (or zero reflectivity, R(E)) at energy E=0 is non-intuitive. However, this has been found earlier and called the ‘threshold anomaly’. Here we show that it is a critical phenomenon and we can have 0≤slant R(0)\\lt 1 when the parameters of the double delta potential satisfy an interesting condition. We also invoke a zero-energy and zero curvature eigenstate (\\psi (x)={Ax}+B) of the delta well between two symmetric rigid walls for R(0)=0. We resolve that the resonant energies and the perfect transmission energies are different and they arise differently.

  18. Maintenance of large deltas through channelization

    NASA Astrophysics Data System (ADS)

    Giosan, L.; Constatinescu, S.; Filip, F.

    2013-12-01

    A new paradigm for delta restoration is currently taking shape using primarily Mississippi delta examples. Here we propose an alternative for delta maintenance primarily envisioned for wave-influenced deltas based on Danube delta experiences. Over the last half century, while the total sediment load of the Danube dramatically decreased due to dam construction on tributaries and its mainstem, a grand experiment was inadvertently run in the Danube delta: the construction of a dense network of canals, which almost tripled the water discharge toward the interior of the delta plain. We use core-based and chart-based sedimentation rates and patterns to explore the delta transition from the natural to an anthropogenic regime, to understand the effects of far-field damming and near-field channelization, and to construct a conceptual model for delta development as a function sediment partition between the delta plain and the delta coastal fringe. We show that sediment fluxes increased to the delta plain due to channelization, counteracting sea level rise. In turn, the delta coastal fringe was most impacted by the Danube's sediment load collapse. Furthermore, we show that morphodynamic feedbacks at the river mouth are crucial in trapping sediment near the coast and constructing wave-dominated deltas or lobes or delaying their destruction. As a general conclusion, we suggest that increased channelization that mimics and enhances natural processes may provide a simple solution for keeping delta plains above sea level and that abandonment of wave-dominated lobes may be the most long term efficient solution for protecting the internal fluvial regions of deltas and provide new coastal growth downcoast.

  19. Using open hole and cased-hole resistivity logs to monitor gas hydrate dissociation during a thermal test in the mallik 5L-38 research well, Mackenzie Delta, Canada

    USGS Publications Warehouse

    Anderson, B.I.; Collett, T.S.; Lewis, R.E.; Dubourg, I.

    2008-01-01

    Gas hydrates, which are naturally occurring ice-like combinations of gas and water, have the potential to provide vast amounts of natural gas from the world's oceans and polar regions. However, producing gas economically from hydrates entails major technical challenges. Proposed recovery methods such as dissociating or melting gas hydrates by heating or depressurization are currently being tested. One such test was conducted in northern Canada by the partners in the Mallik 2002 Gas Hydrate Production Research Well Program. This paper describes how resistivity logs were used to determine the size of the annular region of gas hydrate dissociation that occurred around the wellbore during the thermal test in the Mallik 5L-38 well. An open-hole logging suite, run prior to the thermal test, included array induction, array laterolog, nuclear magnetic resonance and 1.1-GHz electromagnetic propagation logs. The reservoir saturation tool was run both before and after the thermal test to monitor formation changes. A cased-hole formation resistivity log was run after the test.Baseline resistivity values in each formation layer (Rt) were established from the deep laterolog data. The resistivity in the region of gas hydrate dissociation near the wellbore (Rxo) was determined from electromagnetic propagation and reservoir saturation tool measurements. The radius of hydrate dissociation as a function of depth was then determined by means of iterative forward modeling of cased-hole formation resistivity tool response. The solution was obtained by varying the modeled dissociation radius until the modeled log overlaid the field log. Pretest gas hydrate production computer simulations had predicted that dissociation would take place at a uniform radius over the 13-ft test interval. However, the post-test resistivity modeling showed that this was not the case. The resistivity-derived dissociation radius was greatest near the outlet of the pipe that circulated hot water in the wellbore, where the highest temperatures were recorded. The radius was smallest near the center of the test interval, where a conglomerate section with low values of porosity and permeability inhibited dissociation. The free gas volume calculated from the resistivity-derived dissociation radii yielded a value within 20 per cent of surface gauge measurements. These results show that the inversion of resistivity measurements holds promise for use in future gas hydrate monitoring. ?? 2008 Society of Petrophysicists and Well Log Analysts. All rights reserved.

  20. 27 CFR 9.96 - Mississippi Delta.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Mississippi Delta. 9.96... Mississippi Delta. (a) Name. The name of the viticultural area described in this section is “Mississippi Delta.” (b) Approved maps. The appropriate maps for determining the boundaries of the Mississippi...

  1. 27 CFR 9.96 - Mississippi Delta.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Mississippi Delta. 9.96... Mississippi Delta. (a) Name. The name of the viticultural area described in this section is “Mississippi Delta.” (b) Approved maps. The appropriate maps for determining the boundaries of the Mississippi...

  2. 27 CFR 9.96 - Mississippi Delta.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Mississippi Delta. 9.96... Mississippi Delta. (a) Name. The name of the viticultural area described in this section is “Mississippi Delta.” (b) Approved maps. The appropriate maps for determining the boundaries of the Mississippi...

  3. 27 CFR 9.96 - Mississippi Delta.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Mississippi Delta. 9.96... Mississippi Delta. (a) Name. The name of the viticultural area described in this section is “Mississippi Delta.” (b) Approved maps. The appropriate maps for determining the boundaries of the Mississippi...

  4. 27 CFR 9.96 - Mississippi Delta.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2012-04-01 2012-04-01 false Mississippi Delta. 9.96... Mississippi Delta. (a) Name. The name of the viticultural area described in this section is “Mississippi Delta.” (b) Approved maps. The appropriate maps for determining the boundaries of the Mississippi...

  5. Setting the renormalization scale in perturbative QCD: Comparisons of the principle of maximum conformality with the sequential extended Brodsky-Lepage-Mackenzie approach

    NASA Astrophysics Data System (ADS)

    Ma, Hong-Hao; Wu, Xing-Gang; Ma, Yang; Brodsky, Stanley J.; Mojaza, Matin

    2015-05-01

    A key problem in making precise perturbative QCD (pQCD) predictions is how to set the renormalization scale of the running coupling unambiguously at each finite order. The elimination of the uncertainty in setting the renormalization scale in pQCD will greatly increase the precision of collider tests of the Standard Model and the sensitivity to new phenomena. Renormalization group invariance requires that predictions for observables must also be independent on the choice of the renormalization scheme. The well-known Brodsky-Lepage-Mackenzie (BLM) approach cannot be easily extended beyond next-to-next-to-leading order of pQCD. Several suggestions have been proposed to extend the BLM approach to all orders. In this paper we discuss two distinct methods. One is based on the "Principle of Maximum Conformality" (PMC), which provides a systematic all-orders method to eliminate the scale and scheme ambiguities of pQCD. The PMC extends the BLM procedure to all orders using renormalization group methods; as an outcome, it significantly improves the pQCD convergence by eliminating renormalon divergences. An alternative method is the "sequential extended BLM" (seBLM) approach, which has been primarily designed to improve the convergence of pQCD series. The seBLM, as originally proposed, introduces auxiliary fields and follows the pattern of the β0 -expansion to fix the renormalization scale. However, the seBLM requires a recomputation of pQCD amplitudes including the auxiliary fields; due to the limited availability of calculations using these auxiliary fields, the seBLM has only been applied to a few processes at low orders. In order to avoid the complications of adding extra fields, we propose a modified version of seBLM which allows us to apply this method to higher orders. We then perform detailed numerical comparisons of the two alternative scale-setting approaches by investigating their predictions for the annihilation cross section ratio Re+e- at four-loop order in pQCD.

  6. Resilience of Arctic Permafrost Carbon in Mackenzie River Basin: An Incubation Experiment to Observe Priming Potentials and Biodegradability of Arctic Permafrost Peatlands

    NASA Astrophysics Data System (ADS)

    Hedgpeth, A.; Beilman, D.; Crow, S. E.

    2015-12-01

    Arctic permafrost zones cover 25% of the Northern Hemisphere and hold 1672Pg of soil carbon (C) with 277Pg in Arctic permafrost peatlands, which is 1/3 of the CO2 in the atmosphere. This currently protected C is a potential source for increased emissions in a warmer climate. Longer growing seasons resulting in increased plant productivity above and below ground may create new labile C inputs with the potential to affect mineralization of previously stable SOM, known as the priming effect. This study examined the response of soil respiration to labile substrate addition in carbon-rich (42-48 %C) permafrost peatland soils along a N-S transect in the central Mackenzie River Basin (69.2-62.6°N). Active layer and near surface soils (surface Δ14C values > -140.0) were collected from four sites between -10.5 and -5.2 MAT. Soils were spiked with 0.5 mg D-glucose g-1soil, and incubated at 10°C for 23 days to determine potential, short term (i.e., apparent) priming effects. On average glucose addition increased respiration in all samples. One site showed priming evidence in active layer soils despite one-way ANOVA not illustrating statistically significant differences between control and treated final cumulative CO2. Apparent priming effects were seen in two near surface permafrost samples, however cumulative increases in CO2 were not identified as significant. When all results from all sites and depths were considered, the addition of glucose showed no significant effect on total CO2 production relative to controls (p=0.957), suggesting that these sites may be resilient to increased inputs in that little priming evidence was observed. To test the idea that the soils that showed priming effects are of poorer quality, we conducted an additional incubation experiment to explore the biodegradability of these permafrost peatland soils. Soils from these four sites were inoculated and incubated for 17 days. The two sites with observed priming showed the highest biodegradability

  7. Setting the renormalization scale in pQCD: Comparisons of the principle of maximum conformality with the sequential extended Brodsky-Lepage-Mackenzie approach

    SciTech Connect

    Ma, Hong -Hao; Wu, Xing -Gang; Ma, Yang; Brodsky, Stanley J.; Mojaza, Matin

    2015-05-26

    A key problem in making precise perturbative QCD (pQCD) predictions is how to set the renormalization scale of the running coupling unambiguously at each finite order. The elimination of the uncertainty in setting the renormalization scale in pQCD will greatly increase the precision of collider tests of the Standard Model and the sensitivity to new phenomena. Renormalization group invariance requires that predictions for observables must also be independent on the choice of the renormalization scheme. The well-known Brodsky-Lepage-Mackenzie (BLM) approach cannot be easily extended beyond next-to-next-to-leading order of pQCD. Several suggestions have been proposed to extend the BLM approach to all orders. In this paper we discuss two distinct methods. One is based on the “Principle of Maximum Conformality” (PMC), which provides a systematic all-orders method to eliminate the scale and scheme ambiguities of pQCD. The PMC extends the BLM procedure to all orders using renormalization group methods; as an outcome, it significantly improves the pQCD convergence by eliminating renormalon divergences. An alternative method is the “sequential extended BLM” (seBLM) approach, which has been primarily designed to improve the convergence of pQCD series. The seBLM, as originally proposed, introduces auxiliary fields and follows the pattern of the β0-expansion to fix the renormalization scale. However, the seBLM requires a recomputation of pQCD amplitudes including the auxiliary fields; due to the limited availability of calculations using these auxiliary fields, the seBLM has only been applied to a few processes at low orders. In order to avoid the complications of adding extra fields, we propose a modified version of seBLM which allows us to apply this method to higher orders. As a result, we then perform detailed numerical comparisons of the two alternative scale-setting approaches by investigating their predictions for the annihilation cross section ratio R

  8. Shoreline change in 48 river deltas: towards indexing erosion as a criterion of delta vulnerability

    NASA Astrophysics Data System (ADS)

    Besset, Manon; Anthony, Edward; Dussouillez, Philippe; Sabatier, François

    2016-04-01

    River deltas are considered as increasingly vulnerable to environmental modifications resulting from climate change and human activities. Delta vulnerability is associated with a number of drivers, chief among which are depleted sediment supply, changes in water discharge, and pumping of underground fluids. These activities lead to accelerated subsidence and erosion, the twin mechanisms of delta destruction. A lot of attention has been focused on vulnerability resulting from accelerated subsidence. Here, we address the problem of delta erosion based on the analysis of 48 deltas, including 30 of the world's largest deltas. Using satellite images (Landsat, Spot 5, Spot 6) and aerial photographs, we determined for each delta, the change in delta protruberance area over a 30-year period, this being defined as the area of delta protrusion relative to a straight shoreline running across the delta plain and linking the delta to the adjacent non-protruding non-deltaic shoreline. We classified the deltas in terms of net area loss, gain, or stability, the last corresponding to an uncertainty threshold of _0.3% of the delta's protruberance over the 30-year period. The results show that 25 (52%) of the studied set of deltas show area loss, 11 (23%) stability, and 12 (25%) gain. Area loss is more important in deltas with a protruberance area <500 km2 (67% of small deltas) than in the largest deltas (23%), with a protruberance area >500 km2. Besides sediment supply conditions, which are a primary factor in delta erosion, eroding deltas tend to be more commonly subjected to relatively significant levels of wave energy.

  9. [delta-Aminolevulinate dehydratase deficiency].

    PubMed

    Fujita, H; Ishida, N; Akagi, R

    1995-06-01

    delta-Aminolevulinate dehydratase (ALAD: E. C. 4.2.1.24), the second enzyme in the heme biosynthetic pathway, condenses two moles of delta-aminolevulinic acid to form porphobilinogen. ALAD deficiency is well known to develop signs and symptoms of typical hepatic porphyria, and classified into three categories as follows: (i) ALAD porphyria, a genetic defect of the enzyme, (ii) tyrosinemia type I, a genetic defect of fumarylacetoacetase in the tyrosine catabolic pathway, producing succinylacetone (a potent inhibitor of ALAD), and (iii) ALAD inhibition by environmental hazards, such as lead, trichloroethylene, and styrene. In the present article, we will describe molecular and biochemical mechanisms to cause the enzyme defect to discuss the significance of ALAD defect on human health.

  10. Parana River Delta in Argentina

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The Parana River delta is a huge forested marshland about 20 miles northeast of Buenos Aires, Argentina. The area is a very popular tour destination. Guided boat tours can be taken into this vast labyrinth of marsh and trees. The Parana River delta is one of the world's greatest bird-watching destinations. This image highlights the striking contrast between dense forest and wetland marshes, and the deep blue ribbon of the Parana River. This image was acquired by Landsat 7's Enhanced Thematic Mapper plus (ETM+) sensor on May 26, 2000. This is a false-color composite image made using shortwave infrared, near infrared, and green wavelengths. Image provided by the USGS EROS Data Center Satellite Systems Branch.

  11. Deformation characteristics of {delta} phase in the delta-processed Inconel 718 alloy

    SciTech Connect

    Zhang, H.Y.; Zhang, S.H.; Cheng, M.; Li, Z.X.

    2010-01-15

    The hot working characteristics of {delta} phase in the delta-processed Inconel 718 alloy during isothermal compression deformation at temperature of 950 deg. C and strain rate of 0.005 s{sup -1}, were studied by using optical microscope, scanning electron microscope and quantitative X-ray diffraction technique. The results showed that the dissolution of plate-like {delta} phase and the precipitation of spherical {delta} phase particles coexisted during the deformation, and the content of {delta} phase decreased from 7.05 wt.% to 5.14 wt.%. As a result of deformation breakage and dissolution breakage, the plate-like {delta} phase was spheroidized and transferred to spherical {delta} phase particles. In the center with largest strain, the plate-like {delta} phase disappeared and spherical {delta} phase appeared in the interior of grains and grain boundaries.

  12. COMMD1 regulates the delta epithelial sodium channel ({delta}ENaC) through trafficking and ubiquitination

    SciTech Connect

    Chang, Tina; Ke, Ying; Ly, Kevin; McDonald, Fiona J.

    2011-08-05

    Highlights: {yields} The COMM domain of COMMD1 mediates binding to {delta}ENaC. {yields} COMMD1 reduces the cell surface population of {delta}ENaC. {yields} COMMD1 increases the population of {delta}ENaC-ubiquitin. {yields} Both endogenous and transfected {delta}ENaC localize with COMMD1 and transferrin suggesting they are located in early/recycling endosomes. -- Abstract: The delta subunit of the epithelial sodium channel ({delta}ENaC) is a member of the ENaC/degenerin family of ion channels. {delta}ENaC is distinct from the related {alpha}-, {beta}- and {gamma}ENaC subunits, known for their role in sodium homeostasis and blood pressure control, as {delta}ENaC is expressed in brain neurons and activated by external protons. COMMD1 (copper metabolism Murr1 domain 1) was previously found to associate with and downregulate {delta}ENaC activity. Here, we show that COMMD1 interacts with {delta}ENaC through its COMM domain. Co-expression of {delta}ENaC with COMMD1 significantly reduced {delta}ENaC surface expression, and led to an increase in {delta}ENaC ubiquitination. Immunocytochemical and confocal microscopy studies show that COMMD1 promoted localization of {delta}ENaC to the early/recycling endosomal pool where the two proteins were localized together. These results suggest that COMMD1 downregulates {delta}ENaC activity by reducing {delta}ENaC surface expression through promoting internalization of surface {delta}ENaC to an intracellular recycling pool, possibly via enhanced ubiquitination.

  13. Delta hepatitis agent: structural and antigenic properties of the delta-associated particle.

    PubMed Central

    Bonino, F; Hoyer, B; Shih, J W; Rizzetto, M; Purcell, R H; Gerin, J L

    1984-01-01

    Delta agent (delta) was serially passaged to a second and third hepatitis B surface antigen (HBsAg) carrier chimpanzee, using as inoculum the peak delta antigen (delta Ag) serum of an animal previously infected with human serum. The characteristics of serially transmitted delta Ag were similar to those described in first-passage animals. It was consistently detected before the development of anti-delta, in association with a 35- to 37-nm subpopulation of HBsAg particles and a unique low-molecular-weight (5.5 X 10(5)) RNA. RNase susceptibility of the delta-associated RNA and release of delta Ag activity upon treatment of delta-associated particles with detergent revealed that this particle is organized into a virion-like form with the RNA and delta Ag as internal components within a coat of HBsAg. Surface determinants of the delta-associated particle other than HBsAg were not detected by radioimmunoprecipitation experiments, using sera of humans and chimpanzees convalescent from delta hepatitis. The HBsAg-associated particle is the "candidate agent" of delta hepatitis. Images PMID:6698598

  14. Delta II development and flight results

    NASA Astrophysics Data System (ADS)

    Mihara, S. K.

    An account is given of the design modifications of the Delta launch vehicle which have resulted in its Delta II variant, together with flight results obtained with the Delta II to date. Delta II launchers feature a stretched LX tank, a larger-diameter satellite-payload fairing, and an expansion of first-stage nozzle expansion ratio from 8:1 to 12:1. The thrust-augmenting solid rocket boosters use graphite/epoxy composite motor cases. Both two-stage and three-stage launches are discussed, with attention to flights for the Navstar satellites.

  15. Comments on the slip factor and the relation Delta phi = -h Delta theta

    SciTech Connect

    Ng, K.Y.; /Fermilab

    2009-09-01

    The definition of the slip factor can be obtained from the phase equation. However, a derivation using the relation {Delta}{phi} = -h{Delta}{theta} leads to a different slip-factor definition. This apparent paradox is examined in detail and resolved. Here {Delta}{phi} is the rf phase difference and {Delta}{theta} is the azimuthal phase difference around the accelerator ring between an off-momentum particle and the synchronous particle, while h is the rf harmonic.

  16. The hepatitis delta virus and its infection

    SciTech Connect

    Rizzeto, M.; Gerin, J.L.; Purcell, R.H.

    1987-01-01

    This book contains over 50 papers. Some of the titles are: Structure and Replication of the Genome of Hepatitis Delta Virus; Clinical Significance of HDV RNA in HDV Disease; HBV DNA in Delta Chronic Carriers; Prevalance of HBV-DNA Among Anti-Hd Positive Patients; and Characterization of LKM/sub 1/ and LKM/sub 2/ Antigens.

  17. Wave-angle control of delta evolution

    NASA Astrophysics Data System (ADS)

    Ashton, Andrew D.; Giosan, Liviu

    2011-07-01

    Wave-influenced deltas, with large-scale arcuate shapes and demarcated beach ridge complexes, often display an asymmetrical form about their river channel. Here, we use a numerical model to demonstrate that the angles from which waves approach a delta can have a first-order influence upon its plan-view morphologic evolution and sedimentary architecture. The directional spread of incoming waves plays a dominant role over fluvial sediment discharge in controlling the width of an active delta lobe, which in turn affects the characteristic rates of delta progradation. Oblique wave approach (and a consequent net alongshore sediment transport) can lead to the development of morphologic asymmetry about the river in a delta's plan-view form. This plan-form asymmetry can include the development of discrete breaks in shoreline orientation and the appearance of self-organized features arising from shoreline instability along the downdrift delta flank, such as spits and migrating shoreline sand waves—features observed on natural deltas. Somewhat surprisingly, waves approaching preferentially from one direction tend to increase sediment deposition updrift of the river. This ‘morphodynamic groin effect’ occurs when the delta's plan-form aspect ratio is sufficiently large such that the orientation of the shoreline on the downdrift flank is rotated past the angle of maximum alongshore sediment transport, resulting in preferential redirection of fluvial sediment updrift of the river mouth.

  18. Electromagnetic excitation of the Delta(1232) resonance

    SciTech Connect

    V. Pascalutsa; M. Vanderhaeghen; Shin Nan Yang

    2006-09-05

    We review the description of the lowest-energy nucleon excitation--the Delta(1232)-resonance. Much of the recent effort has been focused on the precision measurements of the nucleon to Delta transition by means of electromagnetic probes. We review the results of those measurements and confront them with the state-of-the-art calculations based on chiral effective-field theories (EFT), lattice QCD, and QCD-inspired models. Some of the theoretical approaches are reviewed in detail. In particular, we describe the chiral EFT of QCD in the energy domain of the Delta-resonance, and its applications to the electromagnetic nucleon-to-Delta transition (gamma N Delta). We also describe the recent dynamical and unitary-isobar models of pion electroproduction which are extensively used in the extraction of the gamma* N Delta form factors from experiment. Furthermore, we discuss the link of the gamma* N Delta form factors to generalized parton distributions (GPDs), as well as the predictions of perturbative QCD for these transition form factors. The present status of understanding the Delta-resonance properties and the nature of its excitation is summarized.

  19. The determination of equilibrium constants, DeltaG, DeltaH and DeltaS for vapour interaction with a pharmaceutical drug, using gravimetric vapour sorption.

    PubMed

    Willson, Richard J; Beezer, Anthony E

    2003-06-01

    The application of gravimetric vapour sorption (GVS) to the characterisation of pharmaceutical drugs is often restricted to the study of gross behaviour such as a measure of hygroscopicity. Although useful in early development of a drug substance, for example, in salt selection screening exercises, such types of analysis may not contribute to a fundamental understanding of the properties of the material. This paper reports a new methodology for GVS experimentation that will allow specific sorption parameters to be calculated; equilibrium constant (K), van't Hoff enthalpy change (DeltaH(v)), Gibbs free energy for sorption (DeltaG) and the entropy change for sorption (DeltaS). Unlike other reports of such type of analysis that require the application of a specific model, this method is model free. The analysis does require that over the narrow temperature range of the study DeltaH(v) is constant and there is no change in interaction mechanism.

  20. Delta connected resonant snubber circuit

    DOEpatents

    Lai, J.S.; Peng, F.Z.; Young, R.W. Sr.; Ott, G.W. Jr.

    1998-01-20

    A delta connected, resonant snubber-based, soft switching, inverter circuit achieves lossless switching during dc-to-ac power conversion and power conditioning with minimum component count and size. Current is supplied to the resonant snubber branches solely by the dc supply voltage through the main inverter switches and the auxiliary switches. Component count and size are reduced by use of a single semiconductor switch in the resonant snubber branches. Component count is also reduced by maximizing the use of stray capacitances of the main switches as parallel resonant capacitors. Resonance charging and discharging of the parallel capacitances allows lossless, zero voltage switching. In one embodiment, circuit component size and count are minimized while achieving lossless, zero voltage switching within a three-phase inverter. 36 figs.

  1. Delta connected resonant snubber circuit

    DOEpatents

    Lai, Jih-Sheng; Peng, Fang Zheng; Young, Sr., Robert W.; Ott, Jr., George W.

    1998-01-01

    A delta connected, resonant snubber-based, soft switching, inverter circuit achieves lossless switching during dc-to-ac power conversion and power conditioning with minimum component count and size. Current is supplied to the resonant snubber branches solely by the dc supply voltage through the main inverter switches and the auxiliary switches. Component count and size are reduced by use of a single semiconductor switch in the resonant snubber branches. Component count is also reduced by maximizing the use of stray capacitances of the main switches as parallel resonant capacitors. Resonance charging and discharging of the parallel capacitances allows lossless, zero voltage switching. In one embodiment, circuit component size and count are minimized while achieving lossless, zero voltage switching within a three-phase inverter.

  2. 78 FR 53127 - Delta-Bienville Resource Advisory Committee

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-28

    ...; ] DEPARTMENT OF AGRICULTURE Forest Service Delta-Bienville Resource Advisory Committee AGENCY: Forest Service, USDA. ACTION: Notice of meeting. Date change. SUMMARY: The Delta-Bienville Resource Advisory...

  3. Differentiation of Boc-protected alpha,delta-/delta,alpha- and beta,delta-/delta,beta-hybrid peptide positional isomers by electrospray ionization tandem mass spectrometry.

    PubMed

    Raju, G; Ramesh, V; Srinivas, R; Sharma, G V M; Shoban Babu, B

    2010-06-01

    Two new series of Boc-N-alpha,delta-/delta,alpha- and beta,delta-/delta,beta-hybrid peptides containing repeats of L-Ala-delta(5)-Caa/delta(5)-Caa-L-Ala and beta(3)-Caa-delta(5)-Caa/delta(5)-Caa-beta(3)-Caa (L-Ala = L-alanine, Caa = C-linked carbo amino acid derived from D-xylose) have been differentiated by both positive and negative ion electrospray ionization (ESI) ion trap tandem mass spectrometry (MS/MS). MS(n) spectra of protonated isomeric peptides produce characteristic fragmentation involving the peptide backbone, the Boc-group, and the side chain. The dipeptide positional isomers are differentiated by the collision-induced dissociation (CID) of the protonated peptides. The loss of 2-methylprop-1-ene is more pronounced for Boc-NH-L-Ala-delta-Caa-OCH(3) (1), whereas it is totally absent for its positional isomer Boc-NH-delta-Caa-L-Ala-OCH(3) (7), instead it shows significant loss of t-butanol. On the other hand, second isomeric pair shows significant loss of t-butanol and loss of acetone for Boc-NH-delta-Caa-beta-Caa-OCH(3) (18), whereas these are insignificant for its positional isomer Boc-NH-beta-Caa-delta-Caa-OCH(3) (13). The tetra- and hexapeptide positional isomers also show significant differences in MS(2) and MS(3) CID spectra. It is observed that 'b' ions are abundant when oxazolone structures are formed through five-membered cyclic transition state and cyclization process for larger 'b' ions led to its insignificant abundance. However, b(1)(+) ion is formed in case of delta,alpha-dipeptide that may have a six-membered substituted piperidone ion structure. Furthermore, ESI negative ion MS/MS has also been found to be useful for differentiating these isomeric peptide acids. Thus, the results of MS/MS of pairs of di-, tetra-, and hexapeptide positional isomers provide peptide sequencing information and distinguish the positional isomers.

  4. Influence of different organic fertilizers on quality parameters and the delta(15)N, delta(13)C, delta(2)H, delta(34)S, and delta(18)O values of orange fruit (Citrus sinensis L. Osbeck).

    PubMed

    Rapisarda, Paolo; Camin, Federica; Fabroni, Simona; Perini, Matteo; Torrisi, Biagio; Intrigliolo, Francesco

    2010-03-24

    To investigate the influence of different types of fertilizers on quality parameters, N-containing compounds, and the delta(15)N, delta(13)C, delta(2)H, delta (34)S, and delta(18)O values of citrus fruit, a study was performed on the orange fruit cv. 'Valencia late' (Citrus sinensis L. Osbeck), which was harvested in four plots (three organic and one conventional) located on the same farm. The results demonstrated that different types of organic fertilizers containing the same amount of nitrogen did not effect important changes in orange fruit quality parameters. The levels of total N and N-containing compounds such as synephrine in fruit juice were not statistically different among the different treatments. The delta(15)N values of orange fruit grown under fertilizer derived from animal origin as well as from vegetable compost were statistically higher than those grown with mineral fertilizer. Therefore, delta(15)N values can be used as an indicator of citrus fertilization management (organic or conventional), because even when applied organic fertilizers are of different origins, the natural abundance of (15)N in organic citrus fruit remains higher than in conventional ones. These treatments also did not effect differences in the delta(13)C, delta(2)H, delta(34)S, and delta(18)O values of fruit.

  5. Understand {Delta}P and {Delta}T in turbulent flow heat exchangers

    SciTech Connect

    Steinmeyer, D.

    1996-06-01

    This article attempts to lead the reader down a clear path to the approximate optimum pressure drop ({Delta}P) and temperature difference ({Delta}T) for the most important class of heat exchangers--those with turbulent flow, no phase change, and fluids and flow rates that are similar on both the hot and cold sides. The optimum {Delta}P and {Delta}T are presented in two frameworks: equations for quantitatively estimating the {Delta}P and {Delta}T from fluid properties, the price of energy, the price of heat exchange surface, and the equivalent diameter; and ratios of the bills (i.e., costs) for the {Delta}P and {Delta}T in an optimized design to the bill (i.e., value) for incremental heat exchanger area. The equations can be used in heat exchanger specification. The ratios provide a guide for the designer when the process flowsheet is constructed. As discussed later, these ratios suggest that the engineer should consider the {Delta}P and {Delta}T costs as more important than the capital spent on the heat exchanger.

  6. Identifying hazards associated with lava deltas

    USGS Publications Warehouse

    Poland, Michael P.; Orr, Tim R.

    2014-01-01

    Lava deltas, formed where lava enters the ocean and builds a shelf of new land extending from the coastline, represent a significant local hazard, especially on populated ocean island volcanoes. Such structures are unstable and prone to collapse—events that are often accompanied by small explosions that can deposit boulders and cobbles hundreds of meters inland. Explosions that coincide with collapses of the East Lae ‘Apuki lava delta at Kīlauea Volcano, Hawai‘i, during 2005–2007 followed an evolutionary progression mirroring that of the delta itself. A collapse that occurred when the lava–ocean entry was active was associated with a blast of lithic blocks and dispersal of spatter and fine, glassy tephra. Shortly after delta growth ceased, a collapse exposed hot rock to cold ocean water, resulting in an explosion composed entirely of lithic blocks and lapilli. Further collapse of the delta after several months of inactivity, by which time it had cooled significantly, resulted in no recognizable explosion deposit. Seaward displacement and subsidence of the coastline immediately inland of the delta was measured by both satellite and ground-based sensors and occurred at rates of several centimeters per month even after the lava–ocean entry had ceased. The anomalous deformation ended only after complete collapse of the delta. Monitoring of ground deformation may therefore provide an indication of the potential for delta collapse, while the hazard associated with collapse can be inferred from the level of activity, or the time since the last activity, on the delta.

  7. Niger Delta play types, Nigeria

    SciTech Connect

    Akinpelu, A.O.

    1995-08-01

    Exploration databases can be more valuable when sorted by play type. Play specific databases provide a system to organize E & P data used in evaluating the range of values of parameters for reserve estimation and risk assessment. It is important both in focusing the knowledge base and in orienting research effort. A play in this context is any unique combination of trap, reservoir and source properties with the right dynamics of migration and preservation that results in hydrocarbon accumulation. This definitions helps us to discriminate the subtle differences found with these accumulation settings. About 20 play types were identified around the Niger Delta oil province in Nigeria. These are grouped into three parts: (1) The proven plays-constituting the bulk of exploration prospects in Nigeria today. (2) The unproven or semi-proven plays usually with some successes recorded in a few tries but where knowledge is still inadequate. (3) The unproven or analogous play concept. These are untested but geologically sound ideas which may or may not have been tried elsewhere. With classification and sub grouping of these play types into specific databases, intrinsic attributes and uniqueness of each of them with respect to the four major risk elements and the eight parameters for reserve estimation can be better understood.

  8. Novel diazabicycloalkane delta opioid agonists.

    PubMed

    Loriga, Giovanni; Lazzari, Paolo; Manca, Ilaria; Ruiu, Stefania; Falzoi, Matteo; Murineddu, Gabriele; Bottazzi, Mirko Emilio Heiner; Pinna, Giovanni; Pinna, Gérard Aimè

    2015-09-01

    Here we report the investigation of diazabicycloalkane cores as potential new scaffolds for the development of novel analogues of the previously reported diazatricyclodecane selective delta (δ) opioid agonists, as conformationally constrained homologues of the reference δ agonist (+)-4-[(αR)-α((2S,5R)-4-allyl-2,5-dimethyl-1-piperazinyl)-3-methoxybenzyl]-N,N-diethylbenzamide (SNC80). In particular, we have simplified the diazatricyclodecane motif of δ opioid agonist prototype 1a with bridged bicyclic cores. 3,6-diazabicyclo[3.1.1]heptane, 3,8-diazabicyclo[3.2.1]octane, 3,9-diazabicyclo[3.3.1]nonane, 3,9-diazabicyclo[4.2.1]nonane, and 3,10-diazabicyclo[4.3.1]decane were adopted as core motifs of the novel derivatives. The compounds were synthesized and biologically assayed as racemic (3-5) or diastereoisomeric (6,7) mixtures. All the novel compounds 3-7 showed δ agonism behaviour and remarkable affinity to δ receptors. Amongst the novel derivatives, 3,8-diazabicyclo[3.2.1]octane based compound 4 evidenced improved δ affinity and selectivity relative to SNC80.

  9. Delta-nucleus dynamics: proceedings of symposium

    SciTech Connect

    Lee, T.S.H.; Geesaman, D.F.; Schiffer, J.P.

    1983-10-01

    The appreciation of the role in nuclear physics of the first excited state of the nucleon, the delta ..delta..(1232), has grown rapidly in the past decade. The delta resonance dominates nuclear reactions induced by intermediate energy pions, nucleons, and electromagnetic probes. It is also the most important non-nucleonic degree of freedom needed to resolve many fundamental problems encountered in the study of low-energy nuclear phenomena. Clearly, a new phase of nuclear physics has emerged and conventional thinking must be extended to account for this new dimension of nuclear dynamics. The most challenging problem we are facing is how a unified theory can be developed to describe ..delta..-nucleus dynamics at all energies. In exploring this new direction, it is important to have direct discussions among researchers with different viewpoints. Separate entries were prepared for the 49 papers presented. (WHK)

  10. Contemporary depositional environments of the Omo delta.

    PubMed

    Butzer, K W

    1970-05-01

    Geomorphological and sedimentological studies of depositional environments of the modern Omo River delta and floodplain are essential to an understanding of the Pliocene to Pleistocene Mursi, Nkalabong and Kibish Formations of the Lower Omo Basin (southwestern Ethiopia).

  11. delta(13)C and delta(2)H isotope ratios in amphetamine synthesized from benzaldehyde and nitroethane.

    PubMed

    Collins, Michael; Salouros, Helen; Cawley, Adam T; Robertson, James; Heagney, Aaron C; Arenas-Queralt, Andrea

    2010-06-15

    Previous work in these laboratories and by Butzenlechner et al. and Culp et al. has demonstrated that the delta(2)H isotope value of industrial benzaldehyde produced by the catalytic oxidation of toluene is profoundly positive, usually in the range +300 per thousand to +500 per thousand. Synthetic routes leading to amphetamine, methylamphetamine or their precursors and commencing with such benzaldehyde may be expected to exhibit unusually positive delta(2)H values. Results are presented for delta(13)C and delta(2)H isotope values of 1-phenyl-2-nitropropene synthesized from an industrial source of benzaldehyde, having a positive delta(2)H isotope value, by a Knoevenagel condensation with nitroethane. Results are also presented for delta(13)C and delta(2)H isotope values for amphetamine prepared from the resulting 1-phenyl-2-nitropropene. The values obtained were compared with delta(13)C and delta(2)H isotope values obtained for an amphetamine sample prepared using a synthetic route that did not involve benzaldehyde. Finally, results are presented for samples of benzaldehyde, 1-phenyl-2-nitropropene and amphetamine that had been seized at a clandestine amphetamine laboratory.

  12. Migration in Vulnerable Deltas: A Research Strategy

    NASA Astrophysics Data System (ADS)

    Hutton, C.; Nicholls, R. J.; Allan, A.

    2015-12-01

    C. Hutton1, & R. J. Nicholls1, , 1 University of Southampton, University Road, Southampton, Hampshire, United Kingdom, SO17 1BJ. cwh@geodata. soton.ac.ukAbstractGlobally, deltas contain 500 million people and with rising sea levels often linked to large number of forced migrants are expected in the coming century. However, migration is already a major process in deltas, such as the growth of major cities such as Dhaka and Kolkata. Climate and environmental change interacts with a range of catchment and delta level drivers, which encompass a nexus of sea-level rise, storms, freshwater and sediment supply from the catchment, land degradation, subsidence, agricultural loss and socio-economic stresses. DECCMA (Deltas, Vulnerability and Climate Change: Migration and Adaptation/CARRIA) is investigating migration in the Ganges-Brahmaputra-Meghna (GBM), Mahanadi and Volta Deltas, including the influence of climate change. The research will explore migration from a range of perspectives including governance and stakeholder analysis, demographic analysis, household surveys of sending and receiving areas, macro-economic analysis, and hazards and hotspot analysis both historically and into the future. Migration under climate change will depend on other adaptation in the deltas and this will be examined. Collectively, integrated analysis will be developed to examine migration, other adaptation and development pathways with a particular focus on the implications for the poorest. This will require the development of input scenarios, including expert-derived exogenous scenarios (e.g., climate change) and endogenous scenarios of the delta developed in a participatory manner. This applied research will facilitate decision support methods for the development of deltas under climate change, with a focus on migration and other adaptation strategies.

  13. Lena River Delta formation during the Holocene

    NASA Astrophysics Data System (ADS)

    Bolshiyanov, D.; Makarov, A.; Savelieva, L.

    2014-03-01

    The Lena River Delta, the largest delta of the Arctic Ocean, differs from other deltas because it consists mainly of organomineral sediments, commonly called peat, that contain a huge organic carbon reservoir. The analysis of Delta sediment radiocarbon ages showed that they could not have formed as peat during floodplain bogging, but accumulated when Laptev Sea water level was high and green mosses and sedges grew and were deposited on the surface of flooded marshes. The Lena River Delta formed as organomineral masses and layered sediments accumulated during transgressive phases when sea level rose. In regressive phases, the islands composed of these sediments and other, more ancient islands were eroded. Each new sea transgression led to further accumulation of layered sediments. As a result of alternating transgressive and regressive phases the first alluvial-marine terrace formed, consisting of geological bodies of different ages. Determining the formation age of different areas of the first terrace and other marine terraces on the coast allowed the periods of increasing (8-6 Ka, 4.5-4 Ka, 2.5-1.5 Ka, 0.4-0.2 Ka) and decreasing (5 Ka, 3 Ka, 0.5 Ka) Laptev Sea levels to be distinguished in the Lena Delta area.

  14. Lena River delta formation during the Holocene

    NASA Astrophysics Data System (ADS)

    Bolshiyanov, D.; Makarov, A.; Savelieva, L.

    2015-01-01

    The Lena River delta, the largest delta of the Arctic Ocean, differs from other deltas because it consists mainly of organomineral sediments, commonly called peat, that contain a huge organic carbon reservoir. The analysis of delta sediment radiocarbon ages showed that they could not have formed as peat during floodplain bogging; rather, they accumulated when Laptev Sea water level was high and green mosses and sedges grew and were deposited on the surface of flooded marshes. The Lena River delta formed as organomineral masses and layered sediments accumulated during transgressive phases when sea level rose. In regressive phases, the islands composed of these sediments and other, more ancient islands were eroded. Each new sea transgression led to further accumulation of layered sediments. As a result of alternating transgressive and regressive phases, the first alluvial-marine terrace formed, consisting of geological bodies of different ages. Determining the formation age of different areas of the first terrace and other marine terraces on the coast allowed the periods of increasing (8000-6000 BP (years before present), 4500-4000, 2500-1500, and 400-200 BP) and decreasing (5000, 3000, and 500 BP) Laptev Sea levels to be distinguished in the Lena Delta area.

  15. Preparing Nimbus E on Delta Vehicle

    NASA Technical Reports Server (NTRS)

    1972-01-01

    Nimbus E, the sixth spacecraft in the Nimbus series, is shown preparing for launch on December 12, 1972 from the Western Test Range (WTR), Space Launch Complex SLC-2, West, by the Thrust- Augmented Delta vehicle. The satellite was placed in an 1100-kilometer run-synchronous nearly circular polar orbit. The spacecraft was designated Nimbus 5 upon confirmation that it had achieved successful orbit. The Delta launch vehicle family started development in 1959. The Delta is composed of parts from the Thor, an intermediate-range ballistic missile, as its first stage, and the Vanguard as its second. The first Delta was launched from Cape Canaveral on May 13, 1960 and was powerful enough to deliver a 100-pound spacecraft into geostationary transfer orbit. Delta has been used to launch civil, commercial, and military satellites into orbit. For more information about Delta, please see Chapter 3 in Roger Launius and Dennis Jenkins' book To Reach the High Frontier published by The University Press of Kentucky in 2002.

  16. Phytotaphonomy in subtropical to temperate bayhead delta

    SciTech Connect

    Gastaldo, R.A.

    1986-05-01

    Deltaic regimes act as sinks for hydrocarbon precursors of various organic origin. Most organic detritus incorporated into deltaic sediments is contributed by vegetation established in wetland environments. Processes that incorporate vegetational components in deltaic subenvironments vary, depending on the climate and geography of the sediment-receiving basin. Understanding the phytotaphonomy within the sedimentologic context of different deltas will help workers develop criteria to identify ancient deltaic subenvironments. Some subenvironments are richer in accumulated plant detritus than others; therefore, to plan exploration and exploitation programs, the relationships between sources and reservoirs must be understood. The Mobile delta, Alabama, is a bayhead delta that began prograding through a drowned Pleistocene river valley before 9.5 k.y.B.P. Plant detritus accumulated - and is presently accumulating - in parts of the upper and lower delta flood basins. In the upper delta, large quantities of detritus are deposited in abandoned distributary channels, whereas litter is recycled in clastic swamps. Organic detritus is concentrated in the lower delta in interdistributary bays and marshes. These latter sites contain more productive source sediments for future hydrocarbon resources.

  17. A novel mouse PKC{delta} splice variant, PKC{delta}IX, inhibits etoposide-induced apoptosis

    SciTech Connect

    Kim, Jung D.; Seo, Kwang W.; Lee, Eun A.; Quang, Nguyen N.; Cho, Hong R.; Kwon, Byungsuk

    2011-07-01

    Highlights: {yields} A novel PKC{delta} isoform, named PKC{delta}IX, that lacks the C1 domain and the ATP-binding site is ubiquitously expressed. {yields} PKC{delta}IX inhibits etoposide-induced apoptosis. {yields} PKC{delta}IX may function as an endogenous dominant negative isoform for PKC{delta}. -- Abstract: Protein kinase C (PKC) {delta} plays an important role in cellular proliferation and apoptosis. The catalytic fragment of PKC{delta} generated by caspase-dependent cleavage is essential for the initiation of etoposide-induced apoptosis. In this study, we identified a novel mouse PKC{delta} isoform named PKC{delta}IX (Genebank Accession No. (HQ840432)). PKC{delta}IX is generated by alternative splicing and is ubiquitously expressed, as seen in its full-length PKC{delta}. PKC{delta}IX lacks the C1 domain, the caspase 3 cleavage site, and the ATP binding site but preserves an almost intact c-terminal catalytic domain and a nuclear localization signal (NLS). The structural characteristics of PKC{delta}IX provided a possibility that this PKC{delta} isozyme functions as a novel dominant-negative form for PKC{delta} due to its lack of the ATP-binding domain that is required for the kinase activity of PKC{delta}. Indeed, overexpression of PKC{delta}IX significantly inhibited etoposide-induced apoptosis in NIH3T3 cells. In addition, an in vitro kinase assay showed that recombinant PKC{delta}IX protein could competitively inhibit the kinase activity of PKC{delta}. We conclude that PKC{delta}IX can function as a natural dominant-negative inhibitor of PKC{delta}in vivo.

  18. The Okavango: Whose Delta is it?

    NASA Astrophysics Data System (ADS)

    Magole, Lapologang; Magole, Lefatshe Innocent

    The Okavango Delta is amongst the largest Ramsar sites ( http://www.ramsar.org/sitelist.pdf) in the world and an important wetland for community livelihoods, conservation and tourism in Botswana. Over the years, the utilization of the delta has shifted from communal use to state control, with an increased use for conservation and tourism. This increased use for conservation and tourism has manifested in the physical expansion of the conservation area - Moremi Game Reserve and the formation of Wildlife Management Areas (WMAs) around the reserve, whose primary land use is wildlife utilization. The expansion of the conservation area has translated into several practical matters, including expansion of the area for non-hunting activities or photographic areas. The livelihoods of local communities of the Okavango delta who depended on fishing, hunter-gathering, livestock rearing, rain-fed agriculture and flood recession farming have been negatively affected by the expansion of conservation and tourism in the delta. The livelihoods alternatives in the form of Community Based Natural Resource Management (CBNRM) and tourism have not provided substitutes for the people as the communities are still reliant on the same old livelihood sources as in the past, albeit within smaller and restricted areas. This paper explores the ownership of the natural resources within the Okavango Delta. It asks and attempts to answer the following questions: Who owns and controls the use of the land? Who has access to other resources there in? Who makes the decisions on how the delta resources should be managed and used? Who benefits from the delta resources? We argue firstly that ownership of the delta as defined by legal parameters and demonstrated in natural resource management practice is vested on government. Secondly, government, after assuming ownership of the delta continues to sell its stake to the international community, at the expense of local ownership and access to resources. We

  19. Delta9-THC as a discriminative cue in pigeons: effects of delta8-THC, CBD, and CBN.

    PubMed

    Järbe, T U; Henriksson, B G; Ohlin, G C

    1977-07-01

    Pigeons, trained to discriminate the effects of i.m. injections of delta9-tetrahydrocannabinol (delta9-THC, 0.25 mg/kg) from the effects of the vehicle in a drug discrimination paradigm, were tested for generalization with the isomeric delta8-THC, cannabidiol (CBD) and cannabinol (CBN). When given in sufficient doses, delta8-THC and CBN were found to substitute for delta9-THC whereas CBD did not. CBD and CBN did not antagonize the stimulus effect of delta9-THC. The combination of CBN and delta9-THC rather appeared to accentuate the drug response.

  20. Model for the {Delta}(1600) resonance and {gamma}N{yields}{Delta}(1600) transition

    SciTech Connect

    Ramalho, G.; Tsushima, K.

    2010-10-01

    A covariant spectator constituent quark model is applied to study the {gamma}N{yields}{Delta}(1600) transition. Two processes are important in the transition: a photon couples to the individual quarks of the {Delta}(1600) core (quark core), and a photon couples to the intermediate pion-baryon states (pion cloud). While the quark core contributions are estimated assuming {Delta}(1600) as the first radial excitation of {Delta}(1232), the pion cloud contributions are estimated based on an analogy with the {gamma}N{yields}{Delta}(1232) transition. To estimate the pion cloud contributions in the {gamma}N{yields}{Delta}(1600) transition, we include the relevant intermediate states, {pi}N, {pi}{Delta}, {pi}N(1440) and {pi}{Delta}(1600). Dependence on the four-momentum transfer squared, Q{sup 2}, is predicted for the magnetic dipole transition form factor, G{sub M}*(Q{sup 2}), as well as the helicity amplitudes, A{sub 1/2}(Q{sup 2}) and A{sub 3/2}(Q{sup 2}). The results at Q{sup 2}=0 are compared with the existing data.

  1. A model for the Delta(1600) resonance and gamma N -> Delta(1600) transition

    SciTech Connect

    G. Ramalho, K. Tsushima

    2010-10-01

    A covariant spectator constituent quark model is applied to study the gamma N -> Delta(1600) transition. Two processes are important in the transition: a photon couples to the individual quarks of the Delta(1600) core (quark core), and a photon couples to the intermediate pion-baryon states (pion cloud). While the quark core contributions are estimated assuming Delta(1600) as the first radial excitation of Delta(1232), the pion cloud contributions are estimated based on an analogy with the gamma N -> Delta(1232) transition. To estimate the pion cloud contributions in the gamma N -> Delta(1600) transition, we include the relevant intermediate states, pi-N, pi-Delta, pi-N(1440) and pi-Delta(1600). Dependence on the four-momentum transfer squared, Q2, is predicted for the magnetic dipole transition form factor, GM*(Q2), as well as the helicity amplitudes, A_1/2(Q2) and A_3/2(Q2). The results at Q2=0 are compared with the existing data.

  2. Holocene evolution of a wave-dominated fan-delta: Godavari delta, India

    NASA Astrophysics Data System (ADS)

    Saito, Y.; Nageswara Rao, K.; Nagakumar, K.; Demudu, G.; Rajawat, A.; Kubo, S.; Li, Z.

    2013-12-01

    The Godavari delta is one of the world's largest wave-dominated deltas. The Godavari River arises in the Western Ghats near the west coast of India and drains an area of about 3.1x10^5 km^2, flowing about 1465 km southeast across the Indian peninsula to the Bay of Bengal. The Godavari delta consists of a gentle seaward slope from its apex (12 m elevation) at Rajahmundry and a coastal beach-ridge plain over a distance of about 75 km and covers ~5200 km^2 as a delta plain. The river splits into two major distributary channels, the Gautami and the Vasishta, at a barrage constructed in the mid-1800s. The coastal environment of the deltaic coast is microtidal (~1 m mean tidal range) and wave-dominated (~1.5 m mean wave height in the June-September SW monsoon season, ~0.8 m in the NE monsoon season). Models of the Holocene evolution of the Godavari delta have changed from a zonal progradation model (e.g. Nageswara Rao & Sadakata, 1993) to a truncated cuspate delta model (Nageswara Rao et al., 2005, 2012). Twelve borehole cores (340 m total length), taken in the coastal delta plain during 2010-2013, yielded more than 100 C-14 dates. Sediment facies and C-14 dates from these and previous cores and remote-sensing data support a new delta evolution model. The Holocene coastal delta plain is divided into two parts by a set of linear beach ridges 12-14 km landward from the present shoreline in the central part of the delta. The location of the main depocenter (lobe) has shifted during the Holocene from 1) the center to 2) the west, 3) east, 4) center, 5) west, and 6) east. The linear beach ridges separate the first three from the last three stages. These lobe shifts are controlled by river channel shifts near the apex. Just as the current linear shoreline of the central part of the delta and the concave-up nearshore topography are the result of coastal erosion of a cuspate delta, the linear beach ridges indicate a former eroded shoreline. An unconformity within the deltaic

  3. The DELTA MONSTER: An RPV designed to investigate the aerodynamics of a delta wing platform

    NASA Technical Reports Server (NTRS)

    Connolly, Kristen; Flynn, Mike; Gallagher, Randy; Greek, Chris; Kozlowski, Marc; Mcdonald, Brian; Mckenna, Matt; Sellar, Rich; Shearon, Andy

    1989-01-01

    The mission requirements for the performance of aerodynamic tests on a delta wind planform posed some problems, these include aerodynamic interference; structural support; data acquisition and transmission instrumentation; aircraft stability and control; and propulsion implementation. To eliminate the problems of wall interference, free stream turbulence, and the difficulty of achieving dynamic similarity between the test and actual flight aircraft that are associated with aerodynamic testing in wind tunnels, the concept of the remotely piloted vehicle which can perform a basic aerodynamic study on a delta wing was the main objective for the Green Mission - the Delta Monster. The basic aerodynamic studies were performed on a delta wing with a sweep angle greater than 45 degrees. These tests were performed at various angles of attack and Reynolds numbers. The delta wing was instrumented to determine the primary leading edge vortex formation and location, using pressure measurements and/or flow visualization. A data acquisition system was provided to collect all necessary data.

  4. Tracking Nile Delta vulnerability to Holocene change.

    PubMed

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

    2013-01-01

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

  5. {delta}-mediated pion production in nuclei

    SciTech Connect

    Praet, C.; Lalakulich, O.; Jachowicz, N.; Ryckebusch, J.

    2009-04-15

    We present a fully relativistic formalism for describing neutrino-induced {delta}-mediated single-pion production in nuclei. We assess the ambiguities stemming from the {delta} interactions and quantify the uncertainties in the axial form-factor parameters by comparing with the available bubble-chamber neutrino-scattering data. To include nuclear effects, we turn to a relativistic plane-wave impulse approximation (RPWIA) using realistic bound-state wave functions derived in the Hartree approximation to the {sigma}-{omega} Walecka model. For neutrino energies larger than 1 GeV, we show that a relativistic Fermi-gas model with appropriate binding-energy correction produces results that are comparable to the RPWIA that naturally includes Fermi motion, nuclear-binding effects, and the Pauli exclusion principle. Including {delta} medium modifications roughly halves the RPWIA cross section. Calculations for primary (prior to undergoing final-state interactions) pion production are presented for both electron- and neutrino-induced processes, and a comparison with electron-scattering data and other theoretical approaches is included. We infer that the total {delta}-production strength is underestimated by about 20 to 25%, a fraction that is due to the pionless decay modes of the {delta} in a medium. The model presented in this work can be naturally extended to include the effect of final-state interactions in a relativistic and quantum-mechanical way.

  6. The ecology of the Sacramento-San Joaquin Delta

    SciTech Connect

    Herbold, B.; Moyle, P.B. . Dept. of Wildlife and Fisheries Biology)

    1989-09-01

    This report describes an ecosystem significantly different from other delta ecosystems in North America. The Sacramento-San Joaquin Delta is one of the 60 largest river deltas in the world and is the largest river delta on the west coast. As the hub of California's water system, the delta is of immense municipal, agricultural, and industrial importance. The amount of freshwater that flows through the delta controls the delta's productivity and regulates the life cycles of many of its organisms. The vast estuary of the Sacramento and San Joaquin Rivers is one of the most highly modified and intensively managed estuaries in the world. Biological processes in the delta are obscured by the temporal dynamics of the system. Many of the most significant alterations, such as leveeing, diking, and agricultural practices, are not now recognized as such by most citizens, making conservation and protection of the delta difficult. 308 refs., 43 figs., 11 tabs.

  7. Delta capability for launch of communications satellites

    NASA Technical Reports Server (NTRS)

    Grimes, D. W.; Russell, W. A., Jr.; Kraft, J. D.

    1982-01-01

    The evolution of capabilities and the current performance levels of the Delta launch vehicle are outlined. The first payload was the Echo I passive communications satellite, weighing 179 lb, and placed in GEO in 1960. Emphasis since then has been to use off-the-shelf hardware where feasible. The latest version in the 3924 first stage, 3920 second stage, and Pam D apogee kick motor third stage. The Delta is presently equipped to place 2800 lb in GEO, as was proven with the 2717 lb Anik-D1 satellite. The GEO payload placement performance matches the Shuttle's, and work is therefore under way to enhance the Delta performance to handle more massive payloads. Installation of the Castor-IV solid motor separation system, thereby saving mass by utilizing compressed nitrogen, rather than mechanical thrusters to remove the strap-on boosters, is indicated, together with use of a higher performance propellant and a wider nose fairing.

  8. NATO-3C/Delta launch

    NASA Technical Reports Server (NTRS)

    1978-01-01

    NATO-3C, the third in a series of NATO defense-related communication satellites, is scheduled to be launched on a delta vehicle from the Eastern Test Range no earlier than November 15, 1978. NATO-3A and -3B were successfully launched by Delta vehicles in April 1976 and January 1977, respectively. The NATO-3C spacecraft will be capable of transmitting voice, data, facsimile, and telex messages among military ground stations. The launch vehicle for the NATO-3C mission will be the Delta 2914 configuration. The launch vehicle is to place the spacecraft in a synchronous transfer orbit. The spacecraft Apogee Kick motor is to be fired at fifth transfer orbit apogee to circularize its orbit at geosynchronous altitude of 35,900 km(22,260 miles) above the equator over the Atlantic Ocean somewhere between 45 and 50 degrees W longitude.

  9. Mutagenesis of the borage Delta(6) fatty acid desaturase.

    PubMed

    Sayanova, O; Beaudoin, F; Libisch, B; Shewry, P; Napier, J

    2000-12-01

    The consensus sequence of the third histidine box of a range of Delta(5), Delta(6), Delta(8) and sphingolipid desaturases differs from that of the membrane-bound non-fusion Delta(12) and Delta(15) desaturases in the presence of glutamine instead of histidine. We have used site-directed mutagenesis to determine the importance of glutamine and other residues of the third histidine box and created a chimaeric enzyme to determine the ability of the Cyt b(5) fusion domain from the plant sphingolipid desaturase to substitute for the endogenous domain of the Delta(6) desaturase. PMID:11171152

  10. DNA polymerase III accessory proteins. I. holA and holB encoding delta and delta'.

    PubMed

    Dong, Z; Onrust, R; Skangalis, M; O'Donnell, M

    1993-06-01

    The genes encoding the delta and delta' subunits of the 10-subunit Escherichia coli replicase, DNA polymerase III holoenzyme, have been identified and sequenced. The holA gene encoding delta is located downstream of rlpB at 15.2 min and predicts a 38.7 kda protein. The holB gene encoding delta' is located at 24.3 min and predicts a 36.9-kDa protein. Hence the delta and delta' subunits are unrelated proteins encoded by separate genes. The genes have been used to express and purify delta and delta' in quantity. The predicted amino acid sequence of delta' is homologous to the sequences of the tau and gamma subunits revealing a large amount of structural redundancy within the holoenzyme.

  11. Gamma-delta t-cell lymphomas.

    PubMed

    Foppoli, Marco; Ferreri, Andrés J M

    2015-03-01

    Gamma-delta T-cell lymphomas are aggressive and rare diseases originating from gamma-delta lymphocytes. These cells, which naturally play a role in the innate, non-specific immune response, develop from thymic precursor in the bone marrow, lack the major histocompatibility complex restrictions and can be divided into two subpopulations: Vdelta1, mostly represented in the intestine, and Vdelta2, prevalently located in the skin, tonsils and lymph nodes. Chronic immunosuppression such as in solid organ transplanted subjects and prolonged antigenic exposure are probably the strongest risk factors for the triggering of lymphomagenesis. Two entities are recognised by the 2008 WHO Classification: hepatosplenic gamma-delta T-cell lymphoma (HSGDTL) and primary cutaneous gamma-delta T-cell lymphoma (PCGDTL). The former is more common among young males, presenting with B symptoms, splenomegaly and thrombocytopenia, usually with the absence of nodal involvement. Natural behaviour of HSGDTL is characterised by low response rates, poor treatment tolerability, common early progression of disease and disappointing survival figures. PCGDTL accounts for <1% of all primary cutaneous lymphomas, occurring in adults with relevant comorbidities. Cutaneous lesions may vary, but its clinical behaviour is usually aggressive and long-term survival is anecdotal. Available literature on gamma-delta T-cell lymphomas is fractioned, mostly consisting of case reports or small cumulative series. Therefore, clinical suspicion and diagnosis are usually delayed, and therapeutic management remains to be established. This review critically analyses available evidence on diagnosis, staging and behaviour of gamma-delta T-cell lymphomas, provides recommendations for therapeutic management in routine practice and discusses relevant unmet clinical needs for future studies.

  12. A reduced-complexity model for river delta formation - Part 1: Modeling deltas with channel dynamics

    NASA Astrophysics Data System (ADS)

    Liang, M.; Voller, V. R.; Paola, C.

    2014-07-01

    We develop a reduced-complexity model (RCM) delta formation model, in contrast to reductionist models based on high-resolution computational fluid dynamics. The basic framework of this model (referred in this paper as "DeltaRCM") consists of stochastic parcel-based cellular routing schemes for water and sediment and a set of phenomenological rules for sediment deposition and erosion. The outputs of the model include flow field, water surface topography and bed topography that evolves in time. Results show that DeltaRCM is able to: (1) resolve a wide range of channel dynamics, including elongation, bifurcation, avulsion and migration; (2) in response to the changes in input parameters, produce different types of deltas such as alluvial fan deltas at experimental scale. We also identify three key areas of particular model sensitivity, even at the RCM level: (1) avulsion dynamics is sensitive to dynamic free-surface topography; (2) channel network structure is sensitive to instability at channel mouths which creates bars; and (3) out-of-channel sedimentation is sensitive to water surface slope along channel margins. We also demonstrate a simple stratigraphy tracking component which can display the structure of the deposit in terms of distribution of coarse and fine materials along with the age of the deposit. DeltaRCM is a useful tool for understanding the dynamics of river deltas within a relatively simple cellular representation of water and sediment transport.

  13. All optical binary delta-sigma modulator

    NASA Astrophysics Data System (ADS)

    Sayeh, Mohammad R.; Siahmakoun, Azad

    2005-09-01

    This paper describes a novel A/D converter called "Binary Delta-Sigma Modulator" (BDSM) which operates only with nonnegative signal with positive feedback and binary threshold. This important modification to the conventional delta-sigma modulator makes the high-speed (>100GHz) all-optical implementation possible. It has also the capability to modify its own sampling frequency as well as its input dynamic range. This adaptive feature helps designers to optimize the system performance under highly noisy environment and also manage the power consumption of the A/D converters.

  14. The sensitivity of the ESA DELTA model

    NASA Astrophysics Data System (ADS)

    Martin, C.; Walker, R.; Klinkrad, H.

    2004-01-01

    The debris environment long term analysis (DELTA) model, developed by QinetiQ for the European Space Agency (ESA), allows the future projection of the debris environment throughout Earth orbit. To ensure a sound basis for such future projections, and consequently for assessing the effectiveness of various mitigation measures, it is essential that the sensitivity of the model is examined. This paper discusses the sensitivity of the DELTA model to changes in key model parameters and assumptions. Specifically, the variation in future traffic rates, including the deployment of satellite constellations, and the variation in the break-up model and criteria used to simulate future explosion and collision events.

  15. How Deltas Die - a Case Study of the End of Sedimentation in Two Giant Deltas

    NASA Astrophysics Data System (ADS)

    Macdonald, D.; Robinson, P.; Nicholson, U.

    2013-12-01

    Most well-studied deltas are on passive margins (e.g. Mississippi, Rhone, Ebro), where the main tectonic control on accommodation space is thermal subsidence. As long as the main river in the sediment routing system keeps flowing, there is no particular reason for sedimentation to end, and some deltas have a history extending more than 100 Ma (e.g. Niger at 130 Ma). However, some very large deltas can build out over active margins. For example, the Amur, Orinoco, and Colorado (US) deltas all straddle strike-slip plate boundaries and are much less long-lived than their passive margin counterparts. This paper looks in detail at the end of the deltaic sedimentation in the Pliocene deltas of the Amur River on the island of Sakhalin, and the Colorado River in the Fish Creek-Vallecito Basin of southern California. In both cases the deltas are sand-rich with distant provenances in East Asia and the Colorado Plateau respectively; also they both coexist with locally derived clastic sedimentation. Despite these similarities, there are significant differences between the two deltas as a direct result of the differences in plate boundary movement rates and tectonic state. On Sakhalin, the plate boundary has moved at about 1.95 mm a-1 during the Pliocene and has been in a transpressional state. Primary deltaic sedimentation ended by a three main mechanisms: uplift of the island along the transpressional plate boundary detached the delta from the trunk stream; growth of anticlines over strands of the plate boundary disrupted the consequent delta-top drainage; and late sedimentation involved reworking of the far-travelled deltaic material. In California, where the plate boundary has moved at about 50 mm a-1 in the Pliocene, deltaic sedimentation ceased by translation of the receiving basin from the river mouth. New field and mineralogical data suggest that Colorado River sedimentation waned over a period of about 1 Ma in the Late Pliocene, and was gradually overwhelmed by locally

  16. Modeling delta growth and channel geometry on Wax Lake Delta, Louisiana. Preliminary results

    NASA Astrophysics Data System (ADS)

    Viparelli, E.; Czapiga, M. J.; Li, C.; Shaw, J. B.; Parker, G.

    2013-12-01

    A numerical model of delta growth, in which the distributary channels are assumed to have self-constructed their cross sections, is validated on Wax Lake Delta, Louisiana. As in previous laterally averaged models of delta growth, the delta is divided in a low slope delta top, a steep delta front and a low slope basement. The flow on the delta top is assumed steady, and a backwater formulation is implemented. Since one or more channels can actively transport water and sediment on the delta top during floods, we simplify the problem by assuming that the bed material is transported in one rectangular channel, with width and depth roughly equal to the sum of the active channel widths, and to the average depth of the active channels. The problem is characterized by one equation (i.e. the backwater equation) in two unknowns, the channel width and depth. Another equation is thus needed to close the problem. Under the assumptions that 1) the system is at bankfull flow, and 2) the Shields number in the channels is equal to its channel formative value, our closure relation is a channel-formative criterion. In particular, a recently derived relation to estimate the formative (bankfull) Shields number as a function of the friction slope is implemented. Recent field work on Wax Lake Delta shows that the distributary channels are incising into a relatively stiff basement. In our model we do not attempt to directly model channel incision, but we implicitly account for it with a modified formulation to compute the shoreline migration rate. In this formulation the bed material at the shoreline is trapped in the non-channelized portion of the delta front only. Measured and numerical shoreline migration rates, longitudinal profiles of delta elevation, and channel geometry, i.e. width and depth, are compared. In the relatively near future we plan to 1) use our model to estimate land-building potential of engineered diversions of the Mississippi River, and 2) couple the present model

  17. Susceptibility of Naegleria fowleri to delta 9-tetrahydrocannabinol.

    PubMed Central

    Pringle, H L; Bradley, S G; Harris, L S

    1979-01-01

    Growth of the pathogenic amoeboflagellate Naegleria fowleri is inhibited by delta 9-tetrahydrocannabinol (delta 9-THC). delta 9-THC is amoebostatic at 5 to 50 micrograms/ml. delta 9-THC prevents enflagellation and encystment, but does not impair amoeboid movement. Calf serum at 10 and 20% (vol/vol) reduces the antiamoeba activity of delta 9-THC. Only 1-methoxy delta 8-tetrahydrocannabinol, of 17 cannabinoids tested, failed to inhibit growth of N. fowleri. Antinaeglerial activity was not markedly altered by opening the pyran ring, by converting the cyclohexyl ring to an aromatic ring, or by reversing the hydroxyl and pentyl groups on the benzene ring. delta 9-THC prevented the cytopathic effect of N. fowleri on African green monkey (Vero) cells and human epithelioma (HEp-2) cells in culture. delta 9-THC afforded modest protection to mice infected with N. fowleri. Images PMID:526010

  18. Assembly of hepatitis delta virus particles.

    PubMed Central

    Ryu, W S; Bayer, M; Taylor, J

    1992-01-01

    Hepatitis delta virus (HDV) is a subviral satellite of hepatitis B virus (HBV). Since the RNA genome of HDV can replicate in cultured cells in the absence of HBV, it has been suggested that the only helper function of HBV is to supply HBV coat proteins in the assembly process of HDV particles. To examine the factors involved in such virion assembly, we transiently cotransfected cells with various hepadnavirus constructs and cDNAs of HDV and analyzed the particles released into the medium. We report that the HDV genomic RNA and the delta antigen can be packaged by coat proteins of either HBV or the related hepadnavirus woodchuck hepatitis virus (WHV). Among the three co-carboxy-terminal coat proteins of WHV, the smallest form was sufficient to package the HDV genome; even in the absence of HDV RNA, the delta antigen could be packaged by this WHV coat protein. Also, of the two co-amino-terminal forms of the delta antigen, only the larger form was essential for packaging. Images PMID:1548764

  19. Delta Scorpii unusual brightening to first magnitude

    NASA Astrophysics Data System (ADS)

    Sigismondi, Costantino

    2016-01-01

    The Be star delta Scorpii with a range of variability between 2.35 and 1.65 in visible light is having an unusual brightening to magnitude mV=0.8, as measured on 31 Jan 2016 at 3:56 UT and 5:36 UT from Lanciano, Italy.

  20. Applications of Dirac's Delta Function in Statistics

    ERIC Educational Resources Information Center

    Khuri, Andre

    2004-01-01

    The Dirac delta function has been used successfully in mathematical physics for many years. The purpose of this article is to bring attention to several useful applications of this function in mathematical statistics. Some of these applications include a unified representation of the distribution of a function (or functions) of one or several…

  1. Phi Delta Kappa at the Threshold

    ERIC Educational Resources Information Center

    Walling, Donovan R.

    2006-01-01

    Since its fraternal origins a century ago, Phi Delta Kappa (PDK) International has been foremost a society of individuals joined together in professional collegiality and dedicated to tenets of leadership, service, and research in education. As PDK crosses the threshold into its second century, that early spirit of association lit in 1906, like…

  2. Definition of the {delta} mass and width

    SciTech Connect

    Djukanovic, D.; Scherer, S.; Gegelia, J.

    2007-08-01

    In the framework of effective field theory we show that, at two-loop order, the mass and width of the {delta} resonance defined via the (relativistic) Breit-Wigner parametrization both depend on the choice of field variables. In contrast, the complex-valued position of the pole of the propagator is independent of this choice.

  3. Backwater controls of avulsion location on deltas

    NASA Astrophysics Data System (ADS)

    Chatanantavet, Phairot; Lamb, Michael P.; Nittrouer, Jeffrey A.

    2012-01-01

    River delta complexes are built in part through repeated river-channel avulsions, which often occur about a persistent spatial node creating delta lobes that form a fan-like morphology. Predicting the location of avulsions is poorly understood, but it is essential for wetland restoration, hazard mitigation, reservoir characterization, and delta morphodynamics. Following previous work, we show that the upstream distance from the river mouth where avulsions occur is coincident with the backwater length, i.e., the upstream extent of river flow that is affected by hydrodynamic processes in the receiving basin. To explain this observation we formulate a fluvial morphodynamic model that is coupled to an offshore spreading river plume and subject it to a range of river discharges. Results show that avulsion is less likely in the downstream portion of the backwater zone because, during high-flow events, the water surface is drawn down near the river mouth to match that of the offshore plume, resulting in river-bed scour and a reduced likelihood of overbank flow. Furthermore, during low-discharge events, flow deceleration near the upstream extent of backwater causes enhanced deposition locally and a reduced channel-fill timescale there. Both mechanisms favor preferential avulsion in the upstream part of the backwater zone. These dynamics are fundamentally due to variable river discharges and a coupled offshore river plume, with implications for predicting delta response to climate and sea level change, and fluvio-deltaic stratigraphy.

  4. The Delta Team: Empowering Adolescent Girls.

    ERIC Educational Resources Information Center

    Hood, Marian White

    1994-01-01

    In response to adolescent girls' concerns about teen violence, rumors, grooming, careers, and equity, four women teachers and a woman administrator at a Maryland middle school developed the Delta Program. The program provides positive learning experiences, teaches social skills and conflict management techniques, empowers girls through mentoring…

  5. Quantitative Metrics of Robustness in River Deltas

    NASA Astrophysics Data System (ADS)

    Foufoula-Georgiou, E.; Tejedor, A.; Longjas, A.; Zaliapin, I. V.

    2014-12-01

    Deltas are landforms with channels that deliver water, sediment and nutrient fluxes from rivers to oceans or inland water bodies via multiple pathways. We conceptualize a delta channel network as a rooted acyclic directed graph where channels are modeled by edges and junctions by vertices. We use spectral graph theory - mainly the geometry of the null space of the directed weighted graph Laplacian - to establish a quantitative framework for extracting important structural and dynamics-related information from river deltas. Using this information, we introduce refined metrics of system complexity, such as entropy. Entropy has been proven to be an important measure of the amount of uncertainty in stochastic systems, and therefore a surrogate of the capacity of the system to undergo changes. Here we present an entropic approach to evaluate the robustness of deltas, showing how the two components of entropy: mutual information and conditional entropy can be interpreted in this framework. We also present other metrics that include, among others, resistance distance and number of alternative paths, which quantify the structural complexity of the system. We use these metrics to better classify deltaic systems, quantify their resilience and propose possible management scenarios.

  6. Alkoxy radicals: Delta proton hyperfine couplingsa)

    NASA Astrophysics Data System (ADS)

    Budzinski, Edwin E.; Box, Harold C.

    1985-04-01

    Single crystals of rhamnose were x irradiated at 4.2 K and the ESR and ENDOR spectra taken at 1.6 K. A component of the ESR absorption arises from an alkoxy radical exhibiting an unusual delta proton hyperfine coupling. Parallels between the radiation-induced oxidation of certain carbohydrates and that of amino acids are pointed out.

  7. Faculty Salaries at Delta College. Research Report.

    ERIC Educational Resources Information Center

    Evans, John W.

    In 1989, a study was conducted of faculty salaries at California's San Joaquin Delta Community College (SJDCC). Salary results were compared with community college districts in the State of California, with two specially selected subgroups of colleges comparable to SJDCC, and with all of California's major public and private four-year…

  8. San Joaquin Delta College Student Athlete Study.

    ERIC Educational Resources Information Center

    Lewis, Merrilee R.; Marcopulos, Ernest

    In spring 1988, a study was conducted of students who participated in college athletics at San Joaquin Delta College (SJDC) between 1983-84 and 1987-88. Data collected on each student athlete included ethnicity, sport, place of residence, initial and current reading level, total grade point average (GPA), GPA in athletics and physical education…

  9. {Delta}G and {Delta}q-bar measurements at PHENIX

    SciTech Connect

    Okada, Kensuke; Collaboration: PHENIX Collaboration

    2011-12-14

    RHIC provides a unique opportunity to address the components of the proton spin. In comparison to deep inelastic scattering experiments, the gluon is the main player in proton-proton collisions. PHENIX has measured double spin asymmetries of various processes. Those contain the information of the gluon spin component ({Delta}G). In addition high energy collisions open the unique channel to access flavor dependent information of quark polarization through the real W boson production. Because of the feature of weak interaction, the parity violating process defines the helicity of quarks in the interaction. The single spin asymmetry is the observable. It is especially interesting to probe anti-quark components ({Delta}q-bar). In this article, we report the recent progress of {Delta}G and {Delta}q-bar measurements at PHENIX.

  10. Hard breakup of the deuteron into two {Delta} isobars

    SciTech Connect

    Granados, Carlos G.; Sargsian, Misak M.

    2011-05-15

    We study high-energy photodisintegration of the deuteron into two {Delta} isobars at large center of mass angles within the QCD hard rescattering model (HRM). According to the HRM, the process develops in three main steps: the photon knocks a quark from one of the nucleons in the deuteron; the struck quark rescatters off a quark from the other nucleon sharing the high energy of the photon; then the energetic quarks recombine into two outgoing baryons which have large transverse momenta. Within the HRM, the cross section is expressed through the amplitude of pn{yields}{Delta}{Delta} scattering which we evaluated based on the quark-interchange model of hard hadronic scattering. Calculations show that the angular distribution and the strength of the photodisintegration is mainly determined by the properties of the pn{yields}{Delta}{Delta} scattering. We predict that the cross section of the deuteron breakup to {Delta}{sup ++}{Delta}{sup -} is 4-5 times larger than that of the breakup to the {Delta}{sup +}{Delta}{sup 0} channel. Also, the angular distributions for these two channels are markedly different. These can be compared with the predictions based on the assumption that two hard {Delta} isobars are the result of the disintegration of the preexisting {Delta}{Delta} components of the deuteron wave function. In this case, one expects the angular distributions and cross sections of the breakup in both {Delta}{sup ++}{Delta}{sup -} and {Delta}{sup +}{Delta}{sup 0} channels to be similar.

  11. SDO Delta H Mode Design and Analysis

    NASA Technical Reports Server (NTRS)

    Mason, Paul A.; Starin, Scott R.

    2007-01-01

    While on orbit, disturbance torques on a three axis stabilized spacecraft tend to increase the system momentum, which is stored in the reaction wheels. Upon reaching the predefined momentum capacity (or maximum wheel speed) of the reaction wheel, an external torque must be used to unload the momentum. The purpose of the Delta H mode is to manage the system momentum. This is accomplished by driving the reaction wheels to a target momentum state while the attitude thrusters, which provide an external torque, are used to maintain the attitude. The Delta H mode is designed to meet the mission requirements and implement the momentum management plan. Changes in the requirements or the momentum management plan can lead to design changes in the mode. The momentum management plan defines the expected momentum buildup trend, the desired momentum state and how often the system is driven to the desired momentum state (unloaded). The desired momentum state is chosen based on wheel capacity, wheel configuration, thruster layout and thruster sizing. For the Solar Dynamics Observatory mission, the predefined wheel momentum capacity is a function of the jitter requirements, power, and maximum momentum capacity. Changes in jitter requirements or power limits can lead to changes in the desired momentum state. These changes propagate into the changes in the momentum management plan and therefore the Delta H mode design. This paper presents the analysis and design performed for the Solar Dynamics Observatory Delta H mode. In particular, the mode logic and processing needed to meet requirements is described along with the momentum distribution formulation. The Delta H mode design is validated using the Solar Dynamics Observatory High Fidelity simulator. Finally, a summary of the design is provided along with concluding remarks.

  12. Tracking Nile Delta Vulnerability to Holocene Change

    PubMed Central

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

    2013-01-01

    Understanding deltaic resilience in the face of Holocene climate change and human impacts is an important challenge for the earth sciences in characterizing the full range of present and future wetland responses to global warming. Here, we report an 8000-year mass balance record from the Nile Delta to reconstruct when and how this sedimentary basin has responded to past hydrological shifts. In a global Holocene context, the long-term decrease in Nile Delta accretion rates is consistent with insolation-driven changes in the ‘monsoon pacemaker’, attested throughout the mid-latitude tropics. Following the early to mid-Holocene growth of the Nile’s deltaic plain, sediment losses and pronounced erosion are first recorded after ~4000 years ago, the corollaries of falling sediment supply and an intensification of anthropogenic impacts from the Pharaonic period onwards. Against the backcloth of the Saharan ‘depeopling’, reduced river flow underpinned by a weakening of monsoonal precipitation appears to have been particularly conducive to the expansion of human activities on the delta by exposing productive floodplain lands for occupation and irrigation agriculture. The reconstruction suggests that the Nile Delta has a particularly long history of vulnerability to extreme events (e.g. floods and storms) and sea-level rise, although the present sediment-starved system does not have a direct Holocene analogue. This study highlights the importance of the world’s deltas as sensitive archives to investigate Holocene geosystem responses to climate change, risks and hazards, and societal interaction. PMID:23922692

  13. Genetics Home Reference: activated PI3K-delta syndrome

    MedlinePlus

    ... Health Conditions activated PI3K-delta syndrome activated PI3K-delta syndrome Enable Javascript to view the expand/collapse ... PDF Open All Close All Description Activated PI3K-delta syndrome is a disorder that impairs the immune ...

  14. 78 FR 45592 - DeltaPoint Capital IV, LP;

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-29

    ... ADMINISTRATION DeltaPoint Capital IV, LP; Notice Seeking Exemption Under Section 312 of the Small Business Investment Act, Conflicts of Interest Notice is hereby given that DeltaPoint Capital IV, L.P., 45 East Avenue... Business Administration (``SBA'') Rules and Regulations (13 CFR 107.730). DeltaPoint Capital IV,...

  15. De-Mystifying the Dirac [delta]-Function

    ERIC Educational Resources Information Center

    Lutzer, Carl V.

    2007-01-01

    In this article, we discuss an alternative method of teaching students about the Dirac [delta]-function. The method provides students with the mechanical tools they need in order to work with the [delta]-function in practice, while also fostering a sense of cohesion in the calculus curriculum by presenting the [delta]-function as an evolution of…

  16. The Niger Delta petroleum system; Niger Delta Province, Nigeria, Cameroon, and equatorial Guinea, Africa

    USGS Publications Warehouse

    Tuttle, Michele L.W.; Charpentier, Ronald R.; Brownfield, Michael E.

    1999-01-01

    In the Niger Delta province, we have identified one petroleum system--the Tertiary Niger Delta (Akata-Agbada) petroleum system. The delta formed at the site of a rift triple junction related to the opening of the southern Atlantic starting in the Late Jurassic and continuing into the Cretaceous. The delta proper began developing in the Eocene, accumulating sediments that now are over 10 kilometers thick. The primary source rock is the upper Akata Formation, the marine-shale facies of the delta, with possibly contribution from interbedded marine shale of the lowermost Agbada Formation. Oil is produced from sandstone facies within the Agbada Formation, however, turbidite sand in the upper Akata Formation is a potential target in deep water offshore and possibly beneath currently producing intervals onshore. Known oil and gas resources of the Niger Delta rank the province as the twelfth largest in the world. To date, 34.5 billion barrels of recoverable oil and 93.8 trillion cubic feet of recoverable gas have been discovered. In 1997, Nigeria was the fifth largest crude oil supplier to the United States, supplying 689,000 barrels/day of crude.

  17. 78 FR 22911 - Delta Air Lines, Inc., Reservation Sales and Customer Care Call Center, Seatac, WA; Delta Air...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-17

    ... Employment and Training Administration Delta Air Lines, Inc., Reservation Sales and Customer Care Call Center, Seatac, WA; Delta Air Lines, Inc., Reservation Sales and Customer Care Call Center, Sioux City, IA... workers and former workers of Delta Air Lines, Inc., Reservation Sales and Customer Care Call...

  18. BCAS2 Regulates Delta-Notch Signaling Activity through Delta Pre-mRNA Splicing in Drosophila Wing Development

    PubMed Central

    Huang, Chu-Wei; Chen, Po-Han; Chan, Shih-Peng; Tsao, Yeou-Ping; Lee, Hsiu-Hsiang; Wu, June-Tai; Chen, Show-Li

    2015-01-01

    Previously, we showed that BCAS2 is essential for Drosophila viability and functions in pre-mRNA splicing. In this study, we provide strong evidence that BCAS2 regulates the activity of Delta-Notch signaling via Delta pre-mRNA splicing. Depletion of dBCAS2 reduces Delta mRNA expression and leads to accumulation of Delta pre-mRNA, resulting in diminished transcriptions of Delta-Notch signaling target genes, such as cut and E(spl)m8. Furthermore, ectopic expression of human BCAS2 (hBCAS2) and Drosophila BCAS2 (dBCAS2) in a dBCAS2-deprived fly can rescue dBCAS2 depletion-induced wing damage to the normal phenotypes. These rescued phenotypes are correlated with the restoration of Delta pre-mRNA splicing, which affects Delta-Notch signaling activity. Additionally, overexpression of Delta can rescue the wing deformation by deprivation of dBCAS2; and the depletion of dBCAS2 can restore the aberrant eye associated with Delta-overexpressing retinas; providing supporting evidence for the regulation of Delta-Notch signaling by dBCAS2. Taken together, dBCAS2 participates in Delta pre-mRNA splicing that affects the regulation of Delta-Notch signaling in Drosophila wing development. PMID:26091239

  19. 78 FR 21491 - DeltaPoint Capital IV, L.P., DeltaPoint Capital IV (New York), L.P.; Notice Seeking Exemption...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-10

    ... ADMINISTRATION DeltaPoint Capital IV, L.P., DeltaPoint Capital IV (New York), L.P.; Notice Seeking Exemption... that DeltaPoint Capital IV, L.P. and DeltaPoint Capital IV (New York), L.P., 45 East Avenue, 6th Floor... Business Administration (``SBA'') Rules and Regulations (13 CFR 107.730). DeltaPoint Capital IV,...

  20. Clostridium perfringens Delta-Toxin Induces Rapid Cell Necrosis.

    PubMed

    Seike, Soshi; Miyamoto, Kazuaki; Kobayashi, Keiko; Takehara, Masaya; Nagahama, Masahiro

    2016-01-01

    Clostridium perfringens delta-toxin is a β-pore-forming toxin and a putative pathogenic agent of C. perfringens types B and C. However, the mechanism of cytotoxicity of delta-toxin remains unclear. Here, we investigated the mechanisms of cell death induced by delta-toxin in five cell lines (A549, A431, MDCK, Vero, and Caco-2). All cell lines were susceptible to delta-toxin. The toxin caused rapid ATP depletion and swelling of the cells. Delta-toxin bound and formed oligomers predominantly in plasma membrane lipid rafts. Destruction of the lipid rafts with methyl β-cyclodextrin inhibited delta-toxin-induced cytotoxicity and ATP depletion. Delta-toxin caused the release of carboxyfluorescein from sphingomyelin-cholesterol liposomes and formed oligomers; toxin binding to the liposomes declined with decreasing cholesterol content in the liposomes. Flow cytometric assays with annexin V and propidium iodide revealed that delta-toxin treatment induced an elevation in the population of annexin V-negative and propidium iodide-positive cells. Delta-toxin did not cause the fragmentation of DNA or caspase-3 activation. Furthermore, delta-toxin caused damage to mitochondrial membrane permeability and cytochrome c release. In the present study, we demonstrate that delta-toxin produces cytotoxic activity through necrosis.

  1. Clostridium perfringens Delta-Toxin Induces Rapid Cell Necrosis

    PubMed Central

    Seike, Soshi; Miyamoto, Kazuaki; Kobayashi, Keiko; Takehara, Masaya; Nagahama, Masahiro

    2016-01-01

    Clostridium perfringens delta-toxin is a β-pore-forming toxin and a putative pathogenic agent of C. perfringens types B and C. However, the mechanism of cytotoxicity of delta-toxin remains unclear. Here, we investigated the mechanisms of cell death induced by delta-toxin in five cell lines (A549, A431, MDCK, Vero, and Caco-2). All cell lines were susceptible to delta-toxin. The toxin caused rapid ATP depletion and swelling of the cells. Delta-toxin bound and formed oligomers predominantly in plasma membrane lipid rafts. Destruction of the lipid rafts with methyl β-cyclodextrin inhibited delta-toxin-induced cytotoxicity and ATP depletion. Delta-toxin caused the release of carboxyfluorescein from sphingomyelin-cholesterol liposomes and formed oligomers; toxin binding to the liposomes declined with decreasing cholesterol content in the liposomes. Flow cytometric assays with annexin V and propidium iodide revealed that delta-toxin treatment induced an elevation in the population of annexin V-negative and propidium iodide-positive cells. Delta-toxin did not cause the fragmentation of DNA or caspase-3 activation. Furthermore, delta-toxin caused damage to mitochondrial membrane permeability and cytochrome c release. In the present study, we demonstrate that delta-toxin produces cytotoxic activity through necrosis. PMID:26807591

  2. Clostridium perfringens Delta-Toxin Induces Rapid Cell Necrosis.

    PubMed

    Seike, Soshi; Miyamoto, Kazuaki; Kobayashi, Keiko; Takehara, Masaya; Nagahama, Masahiro

    2016-01-01

    Clostridium perfringens delta-toxin is a β-pore-forming toxin and a putative pathogenic agent of C. perfringens types B and C. However, the mechanism of cytotoxicity of delta-toxin remains unclear. Here, we investigated the mechanisms of cell death induced by delta-toxin in five cell lines (A549, A431, MDCK, Vero, and Caco-2). All cell lines were susceptible to delta-toxin. The toxin caused rapid ATP depletion and swelling of the cells. Delta-toxin bound and formed oligomers predominantly in plasma membrane lipid rafts. Destruction of the lipid rafts with methyl β-cyclodextrin inhibited delta-toxin-induced cytotoxicity and ATP depletion. Delta-toxin caused the release of carboxyfluorescein from sphingomyelin-cholesterol liposomes and formed oligomers; toxin binding to the liposomes declined with decreasing cholesterol content in the liposomes. Flow cytometric assays with annexin V and propidium iodide revealed that delta-toxin treatment induced an elevation in the population of annexin V-negative and propidium iodide-positive cells. Delta-toxin did not cause the fragmentation of DNA or caspase-3 activation. Furthermore, delta-toxin caused damage to mitochondrial membrane permeability and cytochrome c release. In the present study, we demonstrate that delta-toxin produces cytotoxic activity through necrosis. PMID:26807591

  3. Space Radar Image of Mississippi Delta

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This is a radar image of the Mississippi River Delta where the river enters into the Gulf of Mexico along the coast of Louisiana. This multi-frequency image demonstrates the capability of the radar to distinguish different types of wetlands surfaces in river deltas. This image was acquired by the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the space shuttle Endeavour on October 2, 1995. The image is centered on latitude 29.3 degrees North latitude and 89.28 degrees West longitude. The area shown is approximately 63 kilometers by 43 kilometers (39 miles by 26 miles). North is towards the upper right of the image. As the river enters the Gulf of Mexico, it loses energy and dumps its load of sediment that it has carried on its journey through the mid-continent. This pile of sediment, or mud, accumulates over the years building up the delta front. As one part of the delta becomes clogged with sediment, the delta front will migrate in search of new areas to grow. The area shown on this image is the currently active delta front of the Mississippi. The migratory nature of the delta forms natural traps for oil and the numerous bright spots along the outside of the delta are drilling platforms. Most of the land in the image consists of mud flats and marsh lands. There is little human settlement in this area due to the instability of the sediments. The main shipping channel of the Mississippi River is the broad red stripe running northwest to southeast down the left side of the image. The bright spots within the channel are ships. The colors in the image are assigned to different frequencies and polarizations of the radar as follows: red is L-band vertically transmitted, vertically received; green is C-band vertically transmitted, vertically received; blue is X-band vertically transmitted, vertically received. Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars

  4. On regularizations of the Dirac delta distribution

    NASA Astrophysics Data System (ADS)

    Hosseini, Bamdad; Nigam, Nilima; Stockie, John M.

    2016-01-01

    In this article we consider regularizations of the Dirac delta distribution with applications to prototypical elliptic and hyperbolic partial differential equations (PDEs). We study the convergence of a sequence of distributions SH to a singular term S as a parameter H (associated with the support size of SH) shrinks to zero. We characterize this convergence in both the weak-* topology of distributions and a weighted Sobolev norm. These notions motivate a framework for constructing regularizations of the delta distribution that includes a large class of existing methods in the literature. This framework allows different regularizations to be compared. The convergence of solutions of PDEs with these regularized source terms is then studied in various topologies such as pointwise convergence on a deleted neighborhood and weighted Sobolev norms. We also examine the lack of symmetry in tensor product regularizations and effects of dissipative error in hyperbolic problems.

  5. Resurveys of active mudslides, Mississippi Delta

    NASA Astrophysics Data System (ADS)

    Prior, David B.; Coleman, James M.

    1981-03-01

    A survey procedure using digitally acquired, scale-corrected sidescan sonar has been applied to document active submarine landslides in the Mississippi Delta region. Periodic resurveys have been completed for a 70-km2 area in water depths of 10 to 50 m. Sufficient resurvey precision allowed short-term changes in seafloor mapping to be observed. Mudslides showed enlargement by retrogression and downslope surging within a single 5-month period.

  6. Adaptive Delta Management: cultural aspects of dealing with uncertainty

    NASA Astrophysics Data System (ADS)

    Timmermans, Jos; Haasnoot, Marjolijn; Hermans, Leon; Kwakkel, Jan

    2016-04-01

    Deltas are generally recognized as vulnerable to climate change and therefore a salient topic in adaptation science. Deltas are also highly dynamic systems viewed from physical (erosion, sedimentation, subsidence), social (demographic), economic (trade), infrastructures (transport, energy, metropolization) and cultural (multi-ethnic) perspectives. This multi-faceted dynamic character of delta areas warrants the emergence of a branch of applied adaptation science, Adaptive Delta Management, which explicitly focuses on climate adaptation of such highly dynamic and deeply uncertain systems. The application of Adaptive Delta Management in the Dutch Delta Program and its active international dissemination by Dutch professionals results in the rapid dissemination of Adaptive Delta Management to deltas worldwide. This global dissemination raises concerns among professionals in delta management on its applicability in deltas with cultural conditions and historical developments quite different from those found in the Netherlands and the United Kingdom where the practices now labelled as Adaptive Delta Management first emerged. This research develops an approach and gives a first analysis of the interaction between the characteristics of different approaches in Adaptive Delta Management and their alignment with the cultural conditions encountered in various delta's globally. In this analysis, first different management theories underlying approaches to Adaptive Delta Management as encountered in both scientific and professional publications are identified and characterized on three dimensions: The characteristics dimensions used are: orientation on today, orientation on the future, and decision making (Timmermans, 2015). The different underlying management theories encountered are policy analysis, strategic management, transition management, and adaptive management. These four management theories underlying different approaches in Adaptive Delta Management are connected to

  7. WESTAR-V launch on delta

    NASA Astrophysics Data System (ADS)

    1982-01-01

    The WESTAR-V, the second in a series of second-generation, large, 24-transponder communications satellites developed for the Space Communications Company is discussed. It is scheduled to be launched on a Delta vehicle from the Eastern Space and Missile Center no earlier than June 8, 1982. The launch support for this mission will be provided by NASA, on a reimbursable basis, to the Space Communications Company for a fixed price of $25.OM. The launch vehicle for the WESTAR-V mission will be the Delta 3910 configuration which incorporates an extended long tank Thor booster, nine Castor IV strap-on motors, a TR-201 second stage, and an 8-foot fairing. The Delta launch vehicle will place the spacecraft along a suborbital trajectory. The PAM-D stage will then thrust it to a synchronous transfer orbit. Three days after launch, the spacecraft apogee kick motor will be fired to circularize its orbit at geosynchronous altitude of 19,300 NM above the equator at approxmately 75 degrees west longitude.

  8. Delta: Data Reduction for Integrated Application Workflows.

    SciTech Connect

    Lofstead, Gerald Fredrick; Jean-Baptiste, Gregory; Oldfield, Ron A.

    2015-06-01

    Integrated Application Workflows (IAWs) run multiple simulation workflow components con- currently on an HPC resource connecting these components using compute area resources and compensating for any performance or data processing rate mismatches. These IAWs require high frequency and high volume data transfers between compute nodes and staging area nodes during the lifetime of a large parallel computation. The available network band- width between the two areas may not be enough to efficiently support the data movement. As the processing power available to compute resources increases, the requirements for this data transfer will become more difficult to satisfy and perhaps will not be satisfiable at all since network capabilities are not expanding at a comparable rate. Furthermore, energy consumption in HPC environments is expected to grow by an order of magnitude as exas- cale systems become a reality. The energy cost of moving large amounts of data frequently will contribute to this issue. It is necessary to reduce the volume of data without reducing the quality of data when it is being processed and analyzed. Delta resolves the issue by addressing the lifetime data transfer operations. Delta removes subsequent identical copies of already transmitted data during transfers and restores those copies once the data has reached the destination. Delta is able to identify duplicated information and determine the most space efficient way to represent it. Initial tests show about 50% reduction in data movement while maintaining the same data quality and transmission frequency.

  9. Quantitative expression patterns of peroxisome proliferator-activated receptor-{beta}/{delta} (PPAR{beta}/{delta}) protein in mice

    SciTech Connect

    Girroir, Elizabeth E.; Hollingshead, Holly E.; He Pengfei; Zhu Bokai; Perdew, Gary H.; Peters, Jeffrey M.

    2008-07-04

    The expression patterns of PPAR{beta}/{delta} have been described, but the majority of these data are based on mRNA data. To date, there are no reports that have quantitatively examined the expression of PPAR{beta}/{delta} protein in mouse tissues. In the present study, a highly specific PPAR{beta}/{delta} antibody was developed, characterized, and used to examine tissue expression patterns of PPAR{beta}/{delta}. As compared to commercially available anti-PPAR{beta}/{delta} antibodies, one of six polyclonal anti-PPAR{beta}/{delta} antibodies developed was significantly more effective for immunoprecipitation of in vitro-translated PPAR{beta}/{delta}. This antibody was used for quantitative Western blot analysis using radioactive detection methods. Expression of PPAR{beta}/{delta} was highest in colon, small intestine, liver, and keratinocytes as compared to other tissues including heart, spleen, skeletal muscle, lung, brain, and thymus. Interestingly, PPAR{beta}/{delta} expression was localized in the nucleus and RXR{alpha} can be co-immunoprecipitated with nuclear PPAR{beta}/{delta}. Results from these studies demonstrate that PPAR{beta}/{delta} expression is highest in intestinal epithelium, liver, and keratinocytes, consistent with significant biological roles in these tissues.

  10. Explanation of the {delta}{sub 5/2{sup -}}(1930) as a {rho}{delta} bound state

    SciTech Connect

    Gonzalez, P.; Oset, E.; Vijande, J.

    2009-02-15

    We use the {rho}{delta} interaction in the hidden gauge formalism to dynamically generate N* and {delta}* resonances. We show, through a comparison of the results from this analysis and from a quark model study with data, that the {delta}{sub 5/2{sup -}}(1930), {delta}{sub 3/2{sup -}}(1940), and {delta}{sub 1/2{sup -}}(1900) resonances can be assigned to {rho}{delta} bound states. More precisely the {delta}{sub 5/2{sup -}}(1930) can be interpreted as a {rho}{delta} bound state whereas the {delta}{sub 3/2{sup -}}(1940) and {delta}{sub 1/2{sup -}}(1900) may contain an important {rho}{delta} component. This interpretation allows for a solution of a long-standing puzzle concerning the description of these resonances in constituent quark models. In addition we also obtain degenerate J{sup P}=1/2{sup -},3/2{sup -},5/2{sup -} N* states but their assignment to experimental resonances is more uncertain.

  11. Analysis, testing, and evaluation of faulted and unfaulted Wye, Delta, and open Delta connected electromechanical actuators

    NASA Technical Reports Server (NTRS)

    Nehl, T. W.; Demerdash, N. A.

    1983-01-01

    Mathematical models capable of simulating the transient, steady state, and faulted performance characteristics of various brushless dc machine-PSA (power switching assembly) configurations were developed. These systems are intended for possible future use as primemovers in EMAs (electromechanical actuators) for flight control applications. These machine-PSA configurations include wye, delta, and open-delta connected systems. The research performed under this contract was initially broken down into the following six tasks: development of mathematical models for various machine-PSA configurations; experimental validation of the model for failure modes; experimental validation of the mathematical model for shorted turn-failure modes; tradeoff study; and documentation of results and methodology.

  12. Analysis, testing, and evaluation of faulted and unfaulted Wye, Delta, and open Delta connected electromechanical actuators

    NASA Astrophysics Data System (ADS)

    Nehl, T. W.; Demerdash, N. A.

    1983-07-01

    Mathematical models capable of simulating the transient, steady state, and faulted performance characteristics of various brushless dc machine-PSA (power switching assembly) configurations were developed. These systems are intended for possible future use as primemovers in EMAs (electromechanical actuators) for flight control applications. These machine-PSA configurations include wye, delta, and open-delta connected systems. The research performed under this contract was initially broken down into the following six tasks: development of mathematical models for various machine-PSA configurations; experimental validation of the model for failure modes; experimental validation of the mathematical model for shorted turn-failure modes; tradeoff study; and documentation of results and methodology.

  13. Dual regulation of the {delta}Np63 transcriptional activity by {delta}Np63 in human nasopharyngeal carcinoma cell

    SciTech Connect

    Chu, W.-K.; Lee, K.-C.; Chow, S.-E.; Chen, J.-K. . E-mail: jkc508@mail.cgu.edu.tw

    2006-04-21

    p63 splicing variants lacking NH{sub 2}-terminal transactivating domain, known as {delta}Np63, are thought to antagonize p53 and p63 functions and are suggested to play roles in keratinocyte differentiation. Here, we show that {delta}Np63 has a dual-regulatory effect on the activity of its own promoter in NPC-076 cell. Down-regulation of the transcriptional activity is observed when {delta}Np63 is present in low levels. In contrast, up-regulation of {delta}Np63 transcriptional activity is observed when {delta}Np63 is expressed at higher levels. The down-regulation effect is abolished when the p53-binding site of the {delta}Np63 promoter is mutated. In sharp contrast, similar mutation does not affect the up-regulation of the {delta}Np63 transcriptional activity under the same experimental conditions. Further study shows that the up-regulation is correlated with the activation of the STAT3, as the blockade of STAT3 nuclear translocation abolishes the up-regulation by {delta}Np63. Thus, {delta}Np63 exerts a bidirectional regulation of the {delta}Np63 transcriptional activity in NPC-076 cell.

  14. Delta channel networks: 2. Metrics of topologic and dynamic complexity for delta comparison, physical inference, and vulnerability assessment

    NASA Astrophysics Data System (ADS)

    Tejedor, Alejandro; Longjas, Anthony; Zaliapin, Ilya; Foufoula-Georgiou, Efi

    2015-06-01

    Deltas are landforms that deliver water, sediment and nutrient fluxes from upstream rivers to the deltaic surface and eventually to oceans or inland water bodies via multiple pathways. Despite their importance, quantitative frameworks for their analysis lack behind those available for tributary networks. In a companion paper, delta channel networks were conceptualized as directed graphs and spectral graph theory was used to design a quantitative framework for exploring delta connectivity and flux dynamics. Here we use this framework to introduce a suite of graph-theoretic and entropy-based metrics, to quantify two components of a delta's complexity: (1) Topologic, imposed by the network connectivity and (2) Dynamic, dictated by the flux partitioning and distribution. The metrics are aimed to facilitate comparing, contrasting, and establishing connections between deltaic structure, process, and form. We illustrate the proposed analysis using seven deltas in diverse morphodynamic environments and of various degrees of channel complexity. By projecting deltas into a topo-dynamic space whose coordinates are given by topologic and dynamic delta complexity metrics, we show that this space provides a basis for delta comparison and physical insight into their dynamic behavior. The examined metrics are demonstrated to relate to the intuitive notion of vulnerability, measured by the impact of upstream flux changes to the shoreline flux, and reveal that complexity and vulnerability are inversely related. Finally, a spatially explicit metric, akin to a delta width function, is introduced to classify shapes of different delta types.

  15. Measuring Delta Progradation Using Delta Front Flow Patterns: A New Method of Remote Imagery Analysis on the Wax Lake Delta, Louisiana, U.S.A.

    NASA Astrophysics Data System (ADS)

    Estep, J. D.; Shaw, J.; Edmonds, D. A.

    2015-12-01

    Quantifying the progradation of the Wax Lake Delta (WLD), a sub-delta of the Mississippi River Delta, can lend valuable insight into coastal land-building patterns. Previous studies of WLD progradation have relied on subaerially-exposed land for indicating delta extent, but an inherent problem with this method lies in the high variability of exposed land due to vegetative, hydrologic, and atmospheric fluctuations. By mapping water surface films observed in remote imagery which form streaklines along flow paths in the delta, we show that the shallow delta front flow patterns are relatively unaffected by short term water level changes and can be used to evaluate WLD progradation over time. Remotely sensed imagery from multiple sources (infrared aerial photography, SPOT, UAVSAR) spanning from 1988 to 2015 was used to map streaklines from which we calculate a flow direction divergence field across the delta. Measuring the translation of this field through time, such as areas containing extreme divergence values along the delta front, quantifies the progradation over the time elapsed. Preliminary measurements of WLD progradation were subdivided into the eastern, southern, and western thirds of the delta. The eastern third prograded at 110 ±20m/yr from 1988 - 1997, 100 ±40m/yr from 1997 - 2002, and then remained relatively constant to 2015. The southern third prograded at 130 ±20m/yr from 1988 - 1997, 200 ±40m/yr from 1997 - 2002, and remained relatively constant to 2015. The western third prograded at 130 ±30m/yr from 1988 - 1997, 220 ±60 m from 1997 - 2002, and then remained relatively constant from 2002 - 2015. Also of note is the retrogradation on the average of 700 ±400m observed from January to August, 1992 which we interpret as being caused by the impact of Hurricane Andrew. The streakline methodology of evaluating WLD progradation could provide new methods for analysis of land change in other deltas around the world.

  16. Tidal river dynamics: Implications for deltas

    NASA Astrophysics Data System (ADS)

    Hoitink, A. J. F.; Jay, D. A.

    2016-03-01

    Tidal rivers are a vital and little studied nexus between physical oceanography and hydrology. It is only in the last few decades that substantial research efforts have been focused on the interactions of river discharge with tidal waves and storm surges into regions beyond the limit of salinity intrusion, a realm that can extend inland hundreds of kilometers. One key phenomenon resulting from this interaction is the emergence of large fortnightly tides, which are forced long waves with amplitudes that may increase beyond the point where astronomical tides have become extinct. These can be larger than the linear tide itself at more landward locations, and they greatly influence tidal river water levels and wetland inundation. Exploration of the spectral redistribution and attenuation of tidal energy in rivers has led to new appreciation of a wide range of consequences for fluvial and coastal sedimentology, delta evolution, wetland conservation, and salinity intrusion under the influence of sea level rise and delta subsidence. Modern research aims at unifying traditional harmonic tidal analysis, nonparametric regression techniques, and the existing understanding of tidal hydrodynamics to better predict and model tidal river dynamics both in single-thread channels and in branching channel networks. In this context, this review summarizes results from field observations and modeling studies set in tidal river environments as diverse as the Amazon in Brazil, the Columbia, Fraser and Saint Lawrence in North America, the Yangtze and Pearl in China, and the Berau and Mahakam in Indonesia. A description of state-of-the-art methods for a comprehensive analysis of water levels, wave propagation, discharges, and inundation extent in tidal rivers is provided. Implications for lowland river deltas are also discussed in terms of sedimentary deposits, channel bifurcation, avulsion, and salinity intrusion, addressing contemporary research challenges.

  17. On \\delta-derivations of n-ary algebras

    NASA Astrophysics Data System (ADS)

    Kaygorodov, Ivan B.

    2012-12-01

    We give a description of \\delta-derivations of (n+1)-dimensional n-ary Filippov algebras and, as a consequence, of simple finite-dimensional Filippov algebras over an algebraically closed field of characteristic zero. We also give new examples of non-trivial \\delta-derivations of Filippov algebras and show that there are no non-trivial \\delta-derivations of the simple ternary Mal'tsev algebra M_8.

  18. Erosional furrows on continental shelf edge, Mississippi delta region

    NASA Astrophysics Data System (ADS)

    Coleman, James M.; Prior, David B.; Adams, Charles E.

    1981-03-01

    Erosional furrows are recognized on the seafloor off the Mississippi Delta, trending downslope over the shelf edge. They occur in water depths of 150 to 380 m seaward of presently active mudslides on the delta slope. The furrows cross an area of former mudslide deposition and part of the outer shelf. Their origin is likely to be related to cross-shelf secondary helical flows, although delta-front mass movement could cause similar erosional gouging.

  19. Delta-92 Telesat-A operations summary

    NASA Technical Reports Server (NTRS)

    1972-01-01

    Telesat-A, which is the first of the Canadian Telesat satellites to be launched for the domestic satellite communications system is described. The launch vehicle, designated Delta-92 consists of a DSV 3p-11 extended long tank first stage with an MB-3 engine, augmented by low-drag Castor 2 solid motors. The spacecraft has a spin-stabilized electronic system powered by 23,000 solar cells, with sufficient on-board battery capability to provide full capacity power during eclipse of the solar cells. A 60-inch wide circular directional antenna which remains constantly aimed at Canada is included.

  20. delta-biased Josephson tunnel junctions

    SciTech Connect

    Monaco, R.; Mygind, J.; Koshelets, V. P.; Dmitriev, P.

    2010-02-01

    The behavior of a long Josephson tunnel junction drastically depends on the distribution of the dc bias current. We investigate the case in which the bias current is fed in the central point of a one-dimensional junction. Such junction configuration has been recently used to detect the persistent currents circulating in a superconducting loop. Analytical and numerical results indicate that the presence of fractional vortices leads to remarkable differences from the conventional case of uniformly distributed dc bias current. The theoretical findings are supported by detailed measurements on a number of delta-biased samples having different electrical and geometrical parameters.

  1. Investigation of television transmission using adaptive delta modulation principles

    NASA Technical Reports Server (NTRS)

    Schilling, D. L.

    1976-01-01

    The results are presented of a study on the use of the delta modulator as a digital encoder of television signals. The computer simulation of different delta modulators was studied in order to find a satisfactory delta modulator. After finding a suitable delta modulator algorithm via computer simulation, the results were analyzed and then implemented in hardware to study its ability to encode real time motion pictures from an NTSC format television camera. The effects of channel errors on the delta modulated video signal were tested along with several error correction algorithms via computer simulation. A very high speed delta modulator was built (out of ECL logic), incorporating the most promising of the correction schemes, so that it could be tested on real time motion pictures. Delta modulators were investigated which could achieve significant bandwidth reduction without regard to complexity or speed. The first scheme investigated was a real time frame to frame encoding scheme which required the assembly of fourteen, 131,000 bit long shift registers as well as a high speed delta modulator. The other schemes involved the computer simulation of two dimensional delta modulator algorithms.

  2. Delta II rocket prepared for launch of Deep Space 1

    NASA Technical Reports Server (NTRS)

    1998-01-01

    - A solid rocket booster is maneuvered into place for installation on the Boeing Delta 7326 rocket that will launch Deep Space 1 at Launch Pad 17A, Cape Canaveral Air Station. Delta II rockets are medium capacity expendable launch vehicles derived from the Delta family of rockets built and launched since 1960. Since then there have been more than 245 Delta launches. Delta's origins go back to the Thor intermediate-range ballistic missile, which was developed in the mid-1950s for the U.S. Air Force. The Thor -- a single-stage, liquid-fueled rocket -- later was modified to become the Delta launch vehicle. The Delta 7236 has three solid rocket boosters and a Star 37 upper stage. Delta IIs are manufactured in Huntington Beach, Calif. Rocketdyne, a division of The Boeing Company, builds Delta II's main engine in Canoga Park, Calif. Final assembly takes place at the Boeing facility in Pueblo, Colo. Deep Space 1, the first flight in NASA's New Millennium Program, is designed to validate 12 new technologies for scientific space missions of the next century. Onboard experiments include an ion propulsion engine and software that tracks celestial bodies so the spacecraft can make its own navigation decisions without the intervention of ground controllers. Deep Space 1 will complete most of its mission objectives within the first two months, but may also do a flyby of a near-Earth asteroid, 1992 KD, in July 1999.

  3. Elwha River Delta: Geomorphology of a Mixed-Sediment Beach

    NASA Astrophysics Data System (ADS)

    George, D. A.; Warrick, J. J.

    2007-12-01

    The Elwha River drains the Olympic Peninsula of Washington and forms a mixed grain-size delta in the Strait of Juan de Fuca. The Elwha River has been dammed for almost a century, and a pending dam removal project is expected to reconnect upstream sediment sources to the river mouth. Topographic and grain-size mapping of the delta during 1939-2007 is synthesized and the geomorphology and shoreline changes of this system are described. Data sources include historical aerial photographs, airborne LIDAR, semiannual RTK DGPS topographic surveys and grain-size analyses from digital photographs. The delta is divided into three geomorphic regions: west delta, river mouth and east delta. The river mouth is the most complex region due to the river channel movement, side-channels, and bars immediately offshore of the mouth. The east and west delta differ in beach profile and shoreline change rates. The west delta is steep, cuspate and lacks a low-tide terrace. Further, the west delta has exhibited little semi-annual or inter-annual shoreline change. In contrast, the east delta has a steep foreshore, flat low tide terrace that is dominated by cobble, and a consistent trend of erosion during the surveys. These observations can be used to track coastal changes following dam removal on the Elwha River..

  4. Three-dimensional aerodynamic shape optimization of supersonic delta wings

    NASA Technical Reports Server (NTRS)

    Burgreen, Greg W.; Baysal, Oktay

    1994-01-01

    A recently developed three-dimensional aerodynamic shape optimization procedure AeSOP(sub 3D) is described. This procedure incorporates some of the most promising concepts from the area of computational aerodynamic analysis and design, specifically, discrete sensitivity analysis, a fully implicit 3D Computational Fluid Dynamics (CFD) methodology, and 3D Bezier-Bernstein surface parameterizations. The new procedure is demonstrated in the preliminary design of supersonic delta wings. Starting from a symmetric clipped delta wing geometry, a Mach 1.62 asymmetric delta wing and two Mach 1. 5 cranked delta wings were designed subject to various aerodynamic and geometric constraints.

  5. The effect of interference on delta modulation encoded video signals

    NASA Technical Reports Server (NTRS)

    Schilling, D. L.

    1979-01-01

    The results of a study on the use of the delta modulator as a digital encoder of television signals are presented. The computer simulation was studied of different delta modulators in order to find a satisfactory delta modulator. After finding a suitable delta modulator algorithm via computer simulation, the results are analyzed and then implemented in hardware to study the ability to encode real time motion pictures from an NTSC format television camera. The effects were investigated of channel errors on the delta modulated video signal and several error correction algorithms were tested via computer simulation. A very high speed delta modulator was built (out of ECL logic), incorporating the most promising of the correction schemes, so that it could be tested on real time motion pictures. The final area of investigation concerned itself with finding delta modulators which could achieve significant bandwidth reduction without regard to complexity or speed. The first such scheme to be investigated was a real time frame to frame encoding scheme which required the assembly of fourteen, 131,000 bit long shift registers as well as a high speed delta modulator. The other schemes involved two dimensional delta modulator algorithms.

  6. Squeaking and microcracks in a delta-delta ceramic coupling: pin-on-disc study.

    PubMed

    Fukui, Kiyokazu; Kaneuji, Ayumi; Matsumoto, Tadami; Shintani, Kazuhiro

    2016-04-01

    There is a rising concern about squeaking in ceramic-on-ceramic total hip arthroplasty (THA). In pin-on-disc testing of a delta-delta coupling, we reproduced squeaking and observed microcracks on worn surfaces. We used a pin-on-disc machine and made discs and pins by cutting delta ceramic to a diameter of 40 mm (D-D). Cross-linked polyethylene was used for a comparison disc (D-P). We performed the same test using another D-D coupling specimen to confirm reproducibility. Squeaking in the D-D specimen was reproduced in wet conditions, though it was not found in the D-P specimen. Fast Fourier transform analysis showed a peak frequency for squeaking of 2794 Hz. The noise occurred at about 6.6 km of sliding distance. Scanning electron microscopy revealed that the worn surface of the pin in D-D at 10.8 km of sliding distance had some microcracks. However, there was no obvious damage to the worn surface of the pin in D-P at the same sliding distance. We confirmed the reproducibility of these findings, obtaining similar results, including squeaking, from another D-D coupling specimen. Our findings show that squeaking may occur in THA using delta ceramic bearings even if implants are placed to avoid extra-articular impingement of the femoral neck. Although the clinical relevance of microcracks is unknown, they may affect long-term outcomes in THA using delta ceramic bearings.

  7. Status Of The Synchrotron Light Source DELTA

    SciTech Connect

    Berges, U.; Friedl, J.; Hartmann, P.; Schirmer, D.; Schmidt, G.; Sternemann, C.; Tolan, M.; Weis, T.; Westphal, C.; Wille, K.

    2004-05-12

    The Dortmund Electron Accelerator DELTA, located at the University of Dortmund, changed its scope during the last years into a 1.5 GeV synchrotron light source. DELTA is now operated for 3000 h per year including 2000 h dedicated beam time for synchrotron radiation use and 1000 h for machine physics, optimization and maintenance. The status of the accelerator complex is presented together with the beam operation, the installation and commissioning of beamlines and insertion devices. To serve user demands of photon energies up to more than 10 keV a 5.3 T superconducting asymmetric multipole wiggler (SAW) with a critical energy of 7.9 keV has been installed serving three beamlines in the hard X-ray regime with also circular polarization. Two undulator beamlines for photon energies between 5 and 400 eV (U250) and between 55 and 1500 eV (U55) and several dipole beamlines up to 200 eV are under operation. The construction and operation of the different beamlines is done by various universities and laboratories in Nordrhein-Westfalen.

  8. Niger delta deepwater region petroleum potential assessment

    SciTech Connect

    Thomas, D.

    1995-12-18

    On behalf of the Nigerian Ministry of Petroleum and Natural Resources some 23,000 km of high quality 192 channel, 96 fold seismic, and associated gravity and magnetic data were acquired by TGSI-Mabon Geophysical Co. and made available to the industry in 1991. These data were collected over all deepwater blocks in conjunction with the planned 1993 license round. Later, during 1993 and 1994 TGSI with Mabon Ltd. and Stratum Petroleum Services extended the program onto the shelf (7,000 km) and into the ultra deepwater areas (6,400 km), making possible modern studies of the entire offshore delta complex. In assessing the petroleum potential of an undrilled region, it is useful to refer to analogous basins or provinces already with histories of hydrocarbon exploration and discovery. With this in mind, and using limited data from the already drilled areas of Nigeria offshore, the adjacent West Africa salt basin and Brazil in particular, an attempt is made to discuss the hydrocarbon habitat of the undrilled Niger delta deepwater offshore sedimentary sequences.

  9. In vivo metabolism of the methyl homologues of delta-8-tetrahydrocannabinol, delta-9-tetrahydrocannabinol and abn-delta-8-tetrahydrocannabinol in the mouse.

    PubMed

    Brown, N K; Harvey, D J

    1988-04-01

    Methyl-delta-8-tetrahydrocannabinol (methyl-delta-8-THC), methyl-delta-9-THC and abn-methyl-delta-8-THC were synthesized by condensation of orcinol and (1S)-cis-verbenol and were administered to male Charles River CD-1 mice. Extracted hepatic metabolites were isolated by chromatography on Sephadex LH-20 and examined by gas chromatography/mass spectrometry as trimethylsilyl (TMS), (2H9)TMS and methyl ester/TMS derivatives. In addition, metabolic fractions were reduced with lithium aluminium deuteride to convert carboxylic acids to alcohols for structural correlation. Metabolites from methyl-delta-8-THC were similar with respect to the positions substituted to those produced by higher homologues; the major metabolite was methyl-delta-8-THC-11-oic acid. abn-Methyl-delta-8-THC was metabolized in a different manner. The location of the aromatic methyl group at the position adjacent to ring fusion appeared to inhibit metabolism at C(11) to a considerable extent and also to reduce the amount of the resulting alcohol from being oxidized to a carboxylic acid. This caused other metabolic pathways to become dominant, with the result that a compound containing a hydroxy group at the gem-methyl position was the major metabolite. Hydroxylation at this position has not been confirmed with any other cannabinoid, although it is thought to result in trace concentrations of hydroxy metabolites from some compounds. Metabolism of methyl-delta-9-THC was also similar to that of the higher homologues, with the exception that less metabolism occurred at C(8) and a higher percentage of the total metabolic fraction was accounted for by the 11-oic acid metabolite. Minor metabolites were mainly dihydroxy compounds and hydroxylated derivatives of delta-9-THC-11-oic acid.

  10. Multidecadal Fluvial Sediment Fluxes to Deltas under Environmental Change Scenarios

    NASA Astrophysics Data System (ADS)

    Dunn, Frances; Darby, Stephen; Nicholls, Robert

    2016-04-01

    Sediment delivery is vital to sustain delta environments on which over half a billion people live worldwide. Due to factors such as subsidence and sea level rise, deltas sink relative to sea level if sediment is not delivered to and retained on their surfaces. Deltas which sink relative to sea level experience flooding, land degradation and loss, which endangers anthropogenic activities and populations. The future of fluvial sediment fluxes, a key mechanism for sediment delivery to deltas, is uncertain due to complex environmental changes which are predicted to occur over the coming decades. This research investigates fluvial sediment fluxes under environmental changes in order to assess the sustainability of delta environments under potential future scenarios up to 2100. Global datasets of climate change, reservoir construction, and population and GDP as proxies for anthropogenic influence through land use changes are used to drive the catchment numerical model WBMsed, which is being used to investigate the effects of these environmental changes on fluvial sediment delivery. This process produces fluvial sediment fluxes under multiple future scenarios which will be used to assess the future sustainability of a selection of 8 vulnerable deltas, although the approach can be applied to deltas worldwide. By modelling potential future scenarios of fluvial sediment flux, this research contributes to the prognosis for delta environments. The future scenarios will inform management at multiple temporal scales, and indicate the potential consequences for deltas of various anthropogenic activities. This research will both forewarn managers of potentially unsustainable deltas and indicate those anthropogenic activities which encourage or hinder the creation of sustainable delta environments.

  11. The Concentration Dependence of the (Delta)s Term in the Gibbs Free Energy Function: Application to Reversible Reactions in Biochemistry

    ERIC Educational Resources Information Center

    Gary, Ronald K.

    2004-01-01

    The concentration dependence of (delta)S term in the Gibbs free energy function is described in relation to its application to reversible reactions in biochemistry. An intuitive and non-mathematical argument for the concentration dependence of the (delta)S term in the Gibbs free energy equation is derived and the applicability of the equation to…

  12. Late Quaternary shelf-margin deltas, northwest Gulf of Mexico

    SciTech Connect

    Suter, J.R.; Berryhill, H.L. Jr.

    1985-12-01

    Interpretations of 35,000 km (21,900 mi) of single-channel, high-resolution, seismic profiles traversing the continental shelf and upper continental slope of the northwest Gulf of Mexico indicate the existence of five late Wisconsinan shelf margin deltas, including the Rio Grande and Mississippi deltas. The deltas were recognized by geomorphic pattern, high-angle clinoform seismic reflections, and associated with buried river systems. Isopach patterns show that the deltas range in size up to 5000 km/sup 2/ (1900 mi/sup 2/) and reach thicknesses of over 180 m (590 ft). The deposits are elongate parallel with depositional strike, indicating subsidence of the shelf margin as a whole. Internal reflection patterns show the deltas to be fluvially dominated. Multilobate structure resulted from both short-term eustatic sea level fluctuations and delta switching. The late Quaternary shelf-margin deltas provide models for analogous deposits in the ancient record. They are primary indicators of the position of ancient shelf margins, and are important for predicting sand occurrence in that environment as well as farther downslope. As exploration moves to the shelf edge and beyond, instability hazards posed by late Wisconsin deltas, as well as older deposits, must be understood and dealt with. 20 figures.

  13. Late quaternary shelf-margin deltas, northwest Gulf of Mexico

    SciTech Connect

    Suter, J.R.; Berryhill, H.L.

    1985-01-01

    Interpretations of 35,000 km (21,900 mi) of single-channel, high-resolution, seismic profiles traversing the continental shelf and upper continental slope of the northwest Gulf of Mexico indicate the existence of five late Wisconsinan shelf margin deltas, including the Rio Grande and Mississippi deltas. The deltas were recognized by geomorphic pattern, high-angle clinoform seismic reflections, and association with buried river systems. Isopach patterns show that the deltas range in size up to 5,000 km/sup 2/ (1,900 mi/sup 2/) and reach thicknesses of over 180 m (590 ft). The deposits are elongate parallel with depositional strike, indicating subsidence of the shelf margin as a whole. Internal reflection patterns show the deltas to be fluvially dominated. Multilobate structure resulted from both short-term eustatic sea level fluctuations and delta switching. The late Quaternary shelf-margin deltas provide models for analogous deposits in the ancient record. They are primary indicators of the position of ancient shelf margins, and are important for predicting sand occurrence in that environment as well as farther downslope. As exploration moves to the shelf edge and beyond, instability hazards posed by late Wisconsinan deltas, as well as older deposits, must be understood and dealt with.

  14. Assessments of Water Quality in Mississippi Delta Lake Watersheds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This paper summarizes watershed scale research by USDA-ARS National Sedimentation Laboratory scientists on the effects of conservation management on water quality and ecology in oxbow lakes of the Mississippi Delta Region, USA. The Mississippi Delta Region is located in the central portion of the U...

  15. Deborah Partridge Wolfe: Biography of a Kappa Delta Pi Laureate

    ERIC Educational Resources Information Center

    van Hover, Stephanie

    2005-01-01

    In 1988, Kappa Delta Pi selected Dr. Deborah Partridge Wolfe for membership in its Laureate Chapter. Wolfe, a prominent African-American social educator, dedicated her career in education to living and promoting the key ideals of Kappa Delta Pi's mission: scholarship, excellence, diversity, inquiry, reflection, and fellowship. This biography of…

  16. 1. Launch facility, delta 6, approach road and gate, pole ...

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

    1. Launch facility, delta 6, approach road and gate, pole marking the hardened intersite cable system in right center, commercial power pole outside fence in left center, view towards south - Ellsworth Air Force Base, Delta Flight, Launch Facility D-6, 4 miles north of Badlands National Park Headquarters, 4.5 miles east of Jackson County line on county road, Interior, Jackson County, SD

  17. Delta: the First Pion Nucleon Resonance - Its Discovery and Applications

    DOE R&D Accomplishments Database

    Nagle, D. E.

    1984-07-01

    It is attempted to recapture some of the fun and excitement of the pion-scattering work that led to the discovery of what is now called the delta particle. How significant this discovery was became apparent only gradually. That the delta is alive today and thriving at Los Alamos (as well as other places) is described.

  18. Emerging leadership from communities in the Lower Mississippi Delta (LMD)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Delta NIRI (Nutrition Intervention Research Initiative) team has conducted several research studies in the Lower Mississippi Delta (LMD) region employing the community-based participatory research (CBPR) model. Our collaborative work in the LMD focuses on interventions conducted in each of our c...

  19. Women in Leadership Roles in Phi Delta Kappa.

    ERIC Educational Resources Information Center

    Harder, Martha B.; And Others

    The professional and personal characteristics of the men and women in Phi Delta Kappa who hold the top elected positions in local chapters were compared, and the perceptions of these leaders of the impact of allowing women to be members of Phi Delta Kappa were assessed. A 43-item questionnaire was developed and mailed to 1,340 chapter presidents…

  20. Delta: the first pion nucleon resonance - its discovery and applications

    SciTech Connect

    Nagle, D.E.

    1984-07-01

    It is attempted to recapture some of the fun and excitement of the pion-scattering work that led to the discovery of what is now called the delta particle. How significant this discovery was became apparent only gradually. That the delta is alive today and thriving at Los Alamos (as well as other places) is described.

  1. Antinociceptive activity of Delta9-tetrahydrocannabinol non-ionic microemulsions.

    PubMed

    Lazzari, P; Fadda, P; Marchese, G; Casu, G L; Pani, L

    2010-06-30

    Delta(9)-Tetrahydrocannabinol (Delta(9)-THC), the major psychoactive constituent of Cannabis sativa L., has been widely studied for its potential pharmaceutical application in the treatment of various diseases and disturbs. This sparingly soluble terpeno-phenolic compound is not easy to handle and to be formulated in pharmaceutical preparations. The aim of this work was to develop a stable aqueous Delta(9)-THC formulation acceptable for different ways of administration, and to evaluate the therapeutic properties of the new Delta(9)-THC based preparation for pain treatment. Due to the thermodynamic stability and advantages of microemulsion based systems, the study was focused on the identification of aqueous microemulsion based systems containing Delta(9)-THC. Oil in water Delta(9)-THC microemulsions were individuated through phase diagrams construction, using the non-ionic surfactant Solutol HS15, being this surfactant acceptable for parenteral administration in human. A selected microemulsion samples containing 0.2 wt% of Delta(9)-THC, stable up to 52 degrees C, was successfully assayed on animal models of pain. Significant antinociceptive activity has been detected by both intraperitoneal and intragastric administration of the new Delta(9)-THC pharmaceutical preparation. The effect has been highlighted in shorter time if compared to a preparation of the same active principle based on previously reported conventional preparation. PMID:20399844

  2. Exploration gaps exist in Nigeria`s prolific delta

    SciTech Connect

    Thomas, D.

    1995-10-30

    The Niger delta region of the Republic of Nigeria is Africa`s largest oil producing area. It is clear that Nigeria will continue to contribute significantly to world petroleum production well into the 21st century: with increases in recoverable oil reserves in the Niger delta onshore and offshore; the promising potential of the Niger delta deepwater region; and a lesser but not insignificant contribution from the unexplored onshore Benue trough, part of the mid-African rift system, which has already proved to hold substantial oil reserves in the Doba basin of neighboring Chad. This is the first of five parts on Nigeria`s oil and gas potential. The later articles deal with Niger delta oil reserves and production, Niger delta gas reserves, the delta`s deepwater region, and the Benue trough and onshore cretaceous rift basins. This article deals with the geologic setting of the Niger delta-Benue trough region, the synrift deposits, marine sedimentation, margin evolution, geologic strata and reservoirs, reservoir character, structure and traps, hydrocarbon types, geotemperatures, and source rock quality.

  3. California's BAY-DELTA: USGS Science Supports Decision Making

    USGS Publications Warehouse

    Nickles, James; Taylor, Kimberly; Fujii, Roger

    2010-01-01

    U.S. Geological Survey (USGS) scientists are in the forefront of the effort to understand what causes changes in the hydrology, the ecology and the water quality of the Sacramento-San Joaquin River Delta and the San Francisco Bay estuary. Their scientific findings play a crucial role in how agencies manage the Bay-Delta on a daily basis.

  4. 76 FR 23970 - Delta-Bienville Resource Advisory Committee

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-29

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF AGRICULTURE Forest Service Delta-Bienville Resource Advisory Committee AGENCY: Forest Service, USDA. ACTION: Notice of meeting. SUMMARY: The Delta-Bienville Resource Advisory Committee will meet in Forest,...

  5. 75 FR 67079 - Delta-Bienville Resource Advisory Committee

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-01

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF AGRICULTURE Forest Service Delta-Bienville Resource Advisory Committee AGENCY: Forest Service, USDA. ACTION: Notice of meeting. SUMMARY: The Delta-Bienville Resource Advisory Committee will meet in Forest,...

  6. 78 FR 48647 - Delta-Bienville Resource Advisory Committee

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-09

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF AGRICULTURE Forest Service Delta-Bienville Resource Advisory Committee AGENCY: Forest Service, USDA. ACTION: Notice of meeting. SUMMARY: The Delta-Bienville Resource Advisory Committee will meet in Forest,...

  7. 76 FR 12017 - Delta-Bienville Resource Advisory Committee

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-04

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF AGRICULTURE Forest Service Delta-Bienville Resource Advisory Committee AGENCY: Forest Service, USDA. ACTION: Notice of meeting. SUMMARY: The Delta-Bienville Resource Advisory Committee will meet in Forest,...

  8. 76 FR 17105 - Delta-Bienville Resource Advisory Committee

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-28

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF AGRICULTURE Forest Service Delta-Bienville Resource Advisory Committee AGENCY: Forest Service, USDA. ACTION: Notice of meeting. SUMMARY: The Delta-Bienville Resource Advisory Committee will meet in Forest,...

  9. 77 FR 53841 - Delta-Bienville Resource Advisory Committee

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-04

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF AGRICULTURE Forest Service Delta-Bienville Resource Advisory Committee AGENCY: Forest Service, USDA. ACTION: Notice of meeting. SUMMARY: The Delta-Bienville Resource Advisory Committee will meet in Forest,...

  10. Upper-Division Student Difficulties with the Dirac Delta Function

    ERIC Educational Resources Information Center

    Wilcox, Bethany R.; Pollock, Steven J.

    2015-01-01

    The Dirac delta function is a standard mathematical tool that appears repeatedly in the undergraduate physics curriculum in multiple topical areas including electrostatics, and quantum mechanics. While Dirac delta functions are often introduced in order to simplify a problem mathematically, students still struggle to manipulate and interpret them.…

  11. 76 FR 28211 - Delta-Bienville Resource Advisory Committee

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-16

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF AGRICULTURE Forest Service Delta-Bienville Resource Advisory Committee AGENCY: Forest Service, USDA. ACTION: Notice of meeting. SUMMARY: The Delta-Bienville Resource Advisory Committee will meet in Forest,...

  12. Delta Project Planning and Implementation in the Netherlands.

    ERIC Educational Resources Information Center

    Dutt, Ashok K.; Heal, Stephen

    1979-01-01

    Describes a water management project in the Netherlands which is intended to protect the people, land, and property in the Delta Region from abnormally high floods. Presents background for initiation of the Delta Project and discusses problems encountered in the project to date. (Author/DB)

  13. The evolution of a subaqueous delta in the Anthropocene: A stratigraphic investigation of the Brazos River delta, TX USA

    NASA Astrophysics Data System (ADS)

    Carlin, Joseph A.; Dellapenna, Timothy M.

    2015-12-01

    Globally, deltas are increasingly threatened by anthropogenic activities. As a result, deltas now evolve through the combined effects of natural and human-induced processes occurring throughout the fluvial-deltaic system. The Brazos River delta, located along the Texas coast in the northwestern Gulf of Mexico, and its watershed have been impacted by direct and indirect human activities since the late 19th century. This provides an opportunity to investigate how such alterations have shaped the evolution of a delta in the Anthropocene, a time when humans are drivers of geological change. Historic alteration to the delta and watershed include extensive agricultural activity, jetty construction at the mouth in the late 1890s, mouth diversion ~10 km to the southwest in 1929, and reservoir construction throughout the early and mid 20th Century. Three subaerial deltaic geometries provided the framework to connect subaerial deltaic responses, to the anthropogenic alterations, to the resulting stratigraphic characteristics observed in the subaqueous delta. This study utilized high-resolution geophysical data (swath bathymetry, side scan sonar, CHIRP subbottom profiling) on the subaqueous delta to investigate the subaqueous delta stratigraphy and infer the processes that shaped the deltaic record over time. The results showed distinct areas across the subaqueous delta that were dominated by erosion and deposition. Erosional areas corresponded to earlier growth phase depocenters being exposed at the surface, while the depositional areas corresponded to areas with the most recent growth phase depocenter overlying the earlier depocenters. These results highlight that the subaqueous depocenter has migrated westward over time, consistent with the observed changes to the subaerial delta. Additionally, the data showed that evidence for these past growth phases and depocenters may be preserved within the subaqueous delta, even after subaerial portions of the delta returned to pre

  14. Hydrologic Modeling of a Tropical River Delta by Applying Remote Sensing Data: the Niger Delta and its Distributaries.

    NASA Astrophysics Data System (ADS)

    Hannon, M. T.; Syvitski, J. P.; Kettner, A. J.

    2008-12-01

    Delta regions offer rich resources to coastal human populations with their large upstream freshwater sources. Tropical deltas such as the Niger, Nigeria, whose drainage basin incorporates arid regions, receive a significant portion of their runoff from precipitation falling directly on the delta. Between 1970 and 2006, the Niger discharged (Lokoja station) 5000 ± 890 m3/s into upper delta. Here we apply Tropical Rainfall Measurement Mission (TRMM) based precipitation estimates (SB42), with a 0.25° x 0.25° spatial resolution (~100 grid points across the Niger Delta at 3 hourly intervals 1998-2008), and MODIS evapotranspiration (ET) estimates (MOD16), to determine the impact of massive local precipitation events on the routing of water and sediment flux through the Niger Delta's distributaries. The Niger delta receives 2275 mm/y ± 264 mm/y of rainfall with the SE area exceeding 3500 mm/y. The delta's ET varies seasonally between 45 and 65 mm/mo. The in situ generated hydrological runoff is 1675 mm/y, or an equivalent of a discharge 73% the size of the river flux entering the delta. With maximum annual daily discharge from the Niger often exceeding 15,000 m3/s, in combination with the significant in situ runoff, much of the delta's surface is seasonally under floodwaters. LandSat7 imagery indicates delta distributaries that are disconnected from the Niger River, and only drain local precipitation events. This disconnection plays into the discharge and sediment fluxes of these distributaries.

  15. Photoemission Spectroscopy of Delta- Plutonium: Experimental Review

    NASA Astrophysics Data System (ADS)

    Tobin, J. G.

    2002-03-01

    The electronic structure of Plutonium, particularly delta- Plutonium, remains ill defined and without direct experimental verification. Recently, we have embarked upon a program of study of alpha- and delta- Plutonium, using synchrotron radiation from the Advanced Light Source in Berkeley, CA, USA [1]. This work is set within the context of Plutonium Aging [2] and the complexities of Plutonium Science [3]. The resonant photoemission of delta-plutonium is in partial agreement with an atomic, localized model of resonant photoemission, which would be consistent with a correlated electronic structure. The results of our synchrotron- based studies will be compared with those of recent laboratory- based works [4,5,6]. The talk will conclude with a brief discussion of our plans for the future, such as the performance of spin-resolving and dichroic photoemission measurements of Plutonium [7] and the development of single crystal ultrathin films of Plutonium. This work was performed under the auspices of the U.S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under Contract No. W-7405-Eng-48. 1. J. Terry, R.K. Schulze, J.D. Farr, T. Zocco, K. Heinzelman, E. Rotenberg, D.K. Shuh, G. van der Laan, D.A. Arena, and J.G. Tobin, “5f Resonant Photoemission from Plutonium”, UCRL-JC-140782, Surf. Sci. Lett., accepted October 2001. 2. B.D. Wirth, A.J. Schwartz, M.J. Fluss, M.J. Caturla, M.A. Wall, and W.G. Wolfer, MRS Bulletin 26, 679 (2001). 3. S.S. Hecker, MRS Bulletin 26, 667 (2001). 4. T. Gouder, L. Havela, F. Wastin, and J. Rebizant, Europhys. Lett. 55, 705 (2001); MRS Bulletin 26, 684 (2001); Phys. Rev. Lett. 84, 3378 (2000). 5. A.J. Arko, J.J. Joyce, L. Morales, J. Wills, J. Lashley, F. Wastin, and J. Rebizant, Phys. Rev. B 62, 1773 (2000). 6. L.E. Cox, O. Eriksson, and B.R. Cooper, Phys. Rev. B 46, 13571 (1992). 7. J. Tobin, D.A. Arena, B. Chung, P. Roussel, J. Terry, R.K. Schulze, J.D. Farr, T. Zocco, K. Heinzelman, E

  16. Future capabilities of the Delta launch vehicle

    NASA Technical Reports Server (NTRS)

    Grimes, D. W.; Kraft, J. D.

    1982-01-01

    Design features and payload delivery capabilities of the Delta 3920 launch vehicle are presented. The 3920 is the 14th iteration in a series that was first launched in 1960 and has in recent years surpassed a 97 percent success rate. Capacity is 2800 lb to GEO. The second stage has a propellant capacity of 13,244 lb and a specific impulse of 319.2 sec and produces 9443 lb thrust. The first mission is the Landsat-D satellite and 27 more launches are scheduled through 1985, some associated with different upper stage configurations. The 3924 configuration delivers payload to GEO at a cost of $7500/lb. A fairing has been designed to provide back-up for Shuttle payloads, although the larger size reduces the GEO payload to 2715 lb. Performance enhancements may, however, be gained through pneumatic thrusters for the Castor IV engine separation, higher Castor IV thrust levels, increased booster thrust, and a cryogenic second stage.

  17. Head orientation prediction: delta quaternions versus quaternions.

    PubMed

    Himberg, Henry; Motai, Yuichi

    2009-12-01

    Display lag in simulation environments with helmet-mounted displays causes a loss of immersion that degrades the value of virtual/augmented reality training simulators. Simulators use predictive tracking to compensate for display lag, preparing display updates based on the anticipated head motion. This paper proposes a new method for predicting head orientation using a delta quaternion (DQ)-based extended Kalman filter (EKF) and compares the performance to a quaternion EKF. The proposed framework operates on the change in quaternion between consecutive data frames (the DQ), which avoids the heavy computational burden of the quaternion motion equation. Head velocity is estimated from the DQ by an EKF and then used to predict future head orientation. We have tested the new framework with captured head motion data and compared it with the computationally expensive quaternion filter. Experimental results indicate that the proposed DQ method provides the accuracy of the quaternion method without the heavy computational burden.

  18. Actions of delta-9-tetrahydrocannabinol in cannabis

    PubMed Central

    COOPER, ZIVA D.; HANEY, MARGARET

    2009-01-01

    Cannabis use disorders have been recently identified as a relevant clinical issue: a subset of cannabis smokers seeks treatment for their cannabis use, yet few succeed in maintaining long-term abstinence. The rewarding and positive reinforcing effects of the primary psychoactive component of smoked cannabis, delta-9-tetrahydrocannabinol (THC) are mediated by the cannabinoid CB1 receptor. The CB1 receptor has also been shown to mediate cannabinoid dependence and expression of withdrawal upon cessation of drug administration, a phenomenon verified across species. This paper will review findings implicating the CB1 receptor in the behavioural effects of exogenous cannabinoids with a focus on cannabinoid dependence and reinforcement, factors that contribute to the maintenance of chronic cannabis smoking despite negative consequences. Opioidergic modulation of these effects is also discussed. PMID:19367504

  19. Method for dissolving delta-phase plutonium

    DOEpatents

    Karraker, David G.

    1992-01-01

    A process for dissolving plutonium, and in particular, delta-phase plutonium. The process includes heating a mixture of nitric acid, hydroxylammonium nitrate (HAN) and potassium fluoride to a temperature between 40.degree. and 70.degree. C., then immersing the metal in the mixture. Preferably, the nitric acid has a concentration of not more than 2M, the HAN approximately 0.66M, and the potassium fluoride 0.1M. Additionally, a small amount of sulfamic acid, such as 0.1M can be added to assure stability of the HAN in the presence of nitric acid. The oxide layer that forms on plutonium metal may be removed with a non-oxidizing acid as a pre-treatment step.

  20. Adaptive delta modulation systems for video encoding

    NASA Technical Reports Server (NTRS)

    Lei, T.-L. R.; Scheinberg, N.; Schilling, D. L.

    1977-01-01

    This paper describes several adaptive delta modulators designed to encode video signals. One- and two-dimensional ADM algorithms are discussed and compared. Results are shown for bit rates of 2 bits/pixel, 1 bit/pixel and 0.5 bits/pixel. Pictures showing the difference between the encoded-decoded pictures and the original pictures are presented. Results are also presented to illustrate the effect of channel errors on the reconstructed picture. A two-dimensional ADM using interframe encoding is also presented. This system operates at the rate of 2 bits/pixel and produces excellent quality pictures when there is little motion. We also describe and illustrate the effect of large amounts of motion on the reconstructed picture.

  1. Quantitative metrics that describe river deltas and their channel networks

    NASA Astrophysics Data System (ADS)

    Edmonds, Douglas A.; Paola, Chris; Hoyal, David C. J. D.; Sheets, Ben A.

    2011-12-01

    Densely populated river deltas are losing land at an alarming rate and to successfully restore these environments we must understand the details of their morphology. Toward this end we present a set of five metrics that describe delta morphology: (1) the fractal dimension, (2) the distribution of island sizes, (3) the nearest-edge distance, (4) a synthetic distribution of sediment fluxes at the shoreline, and (5) the nourishment area. The nearest-edge distance is the shortest distance to channelized or unchannelized water from a given location on the delta and is analogous to the inverse of drainage density in tributary networks. The nourishment area is the downstream delta area supplied by the sediment coming through a given channel cross section and is analogous to catchment area in tributary networks. As a first step, we apply these metrics to four relatively simple, fluvially dominated delta networks. For all these deltas, the average nearest-edge distances are remarkably constant moving down delta suggesting that the network organizes itself to maintain a consistent distance to the nearest channel. Nourishment area distributions can be predicted from a river mouth bar model of delta growth, and also scale with the width of the channel and with the length of the longest channel, analogous to Hack's law for drainage basins. The four delta channel networks are fractal, but power laws and scale invariance appear to be less pervasive than in tributary networks. Thus, deltas may occupy an advantageous middle ground between complete similarity and complete dissimilarity, where morphologic differences indicate different behavior.

  2. Radioactive mineral springs in Delta County, Colorado

    USGS Publications Warehouse

    Cadigan, Robert A.; Rosholt, John N.; Felmlee, J. Karen

    1976-01-01

    The system of springs in Delta County, Colo., contains geochemical clues to the nature and location of buried uranium-mineralized rock. The springs, which occur along the Gunnison River and a principal tributary between Delta and Paonia, are regarded as evidence of a still-functioning hydrothermal system. Associated with the springs are hydrogen sulfide and sulfur dioxide gas seeps, carbon dioxide gas-powered geysers, thick travertine deposits including radioactive travertine, and a flowing warm-water (41?C) radioactive well. Geochemical study of the springs is based on surface observations, on-site water-property measurements, and sampling of water, travertine, soft precipitates, and mud. The spring deposits are mostly carbonates, sulfates, sulfides, and chlorides that locally contain notable amounts of some elements, such as arsenic, barium, lithium, and radium. Samples from five localities have somewhat different trace element assemblages even though they are related to the same hydrothermal system. All the spring waters but one are dominated by sodium chloride or sodium bicarbonate. The exception is an acid sulfate water with a pH of 2.9, which contains high concentrations of aluminum and iron. Most of the detectable radioactivity is due to the presence of radium-226, a uranium daughter product, but at least one spring precipitate contains abundant radium-228, a thorium daughter product. The 5:1 ratio of radium-228 to radium-226 suggests the proximity of a vein-type deposit as a source for the radium. The proposed locus of a thorium-uranium mineral deposit is believed to lie in the vicinity of Paonia, Colo. Exact direction and depth are not determinable from data now available.

  3. Non-V delta 2 gamma delta T lymphocytes as effectors of cancer immunotherapy

    PubMed Central

    Fisher, Jonathan; Kramer, Anne-Marijn; Gustafsson, Kenth; Anderson, John

    2014-01-01

    Gamma delta T cells (γδT) are potent mediators of antitumor cytotoxicity and have shown promising efficacy in early phase clinical trials. Most is known about the tumoricidal properties of cells bearing the Vδ2 T cell receptor chain, but recent studies have demonstrated that cells with the Vδ1 chain and those with neither Vδ1 nor Vδ2 chains have properties which may make them more attractive anticancer effectors in adoptive immunotherapy. PMID:25949890

  4. Potential exposure of larval and juvenile delta smelt to dissolved pesticides in the Sacramento-San Joaquin Delta, California

    USGS Publications Warehouse

    Kuivila, K.M.; Moon, G.E.

    2004-01-01

    The San Francisco Estuary is critical habitat for delta smelt Hypomesus transpacificus, a fish whose abundance has declined greatly since 1983 and is now listed as threatened. In addition, the estuary receives drainage from the Central Valley, an urban and agricultural region with intense and diverse pesticide usage. One possible factor of the delta smelt population decline is pesticide toxicity during vulnerable larval and juvenile stages, but pesticide concentrations are not well characterized in delta smelt spawning and nursery habitat. The objective of this study was to estimate the potential exposure of delta smelt during their early life stages to dissolved pesticides. For 3 years (1998-2000), water samples from the Sacramento-San Joaquin Delta were collected during April-June in coordination with the California Department of Fish and Game's delta smelt early life stage monitoring program. Samples were analyzed for pesticides using solid-phase extraction and gas chromatography/mass spectrometry. Water samples contained multiple pesticides, ranging from 2 to 14 pesticides in each sample. In both 1999 and 2000, elevated concentrations of pesticides overlapped in time and space with peak densities of larval and juvenile delta smelt. In contrast, high spring outflows in 1998 transported delta smelt away from the pesticide sampling sites so that exposure could not be estimated. During 2 years, larval and juvenile delta smelt were potentially exposed to a complex mixture of pesticides for a minimum of 2-3 weeks. Although the measured concentrations were well below short-term (96-h) LC50 values for individual pesticides, the combination of multiple pesticides and lengthy exposure duration could potentially have lethal or sublethal effects on delta smelt, especially during early larval development.

  5. Water and Sand Transport Pathways Through the Delta Front, Wax Lake delta, USA

    NASA Astrophysics Data System (ADS)

    Shaw, J. B.; Mohrig, D.

    2011-12-01

    The Wax Lake delta (WLD) is considered a type example of the river dominated delta due to its fan-like shape and network of bifurcating channels. We investigate the formative processes of the WLD's morphology using water and sediment data collected during the 2011 spring flood. Our study focuses on the delta front; the ~4 km wide region seaward of the subaerial delta that is characterized by (a) sub-aqueous extensions of the sub-aerial channels, and (b) broad, shallow, unchannelized zones positioned between the sub-aqueous channels. We find that while water flux is widely distributed between the channelized and non-channelized zones, the sand flux is focused in the sub-aqueous channels of the delta front. Flow is faster in the channels than non-channelized areas (0.7 versus 0.15 m/s), but the large width discrepancy (200 m wide channels vs 3500 m wide non-channelized zones) permits large water discharges in the non-channelized zones. In one measured case, we calculate that 70% of discharge (670 m3/s) bled from neighboring channels into a non-channelized zone over 3 km of sub-aqueous channel length. In contrast, sand flux distribution is focused in sub-aqueous channels and extends no further than 200 m from the channel margin. Fine sand is transported in suspension because of sufficiently high shear velocities (u* = 2-5 cm/s). Sand is not transported through unchannelized zones due to insufficient shear (u* <1.4 cm/s). Levees on either side of a sub-aqueous channel define this strong lateral convergence of sand flux. Factors controlling cross-channel flux from channels to non-channelized zones are likely to be the velocity differential, the ratio of channel depth to levee depth and change in width of the unchannelized area with downstream distance (0.75 m/m). We hypothesize that under certain conditions, lateral transport of water and sand out of channels may initiate a channel bifurcation, more in the manner of an avulsion than of flow splitting by mouth bar

  6. The Mississippi Delta Region: Past, Present, and Future

    NASA Astrophysics Data System (ADS)

    Blum, Michael D.; Roberts, Harry H.

    2012-05-01

    The Mississippi delta region of south Louisiana houses a wealth of resources within a dynamic, subsiding landscape. Foundations for the delta region reflect Neogene evolution of the depocenter, whereas details of the modern landscape reflect late Pleistocene to Holocene evolution of the alluvial-deltaic plain. The Holocene delta plain was constructed by cyclical growth of deltaic headlands, followed by avulsion and relocation of the fluvial sediment source. Abandoned headlands were then submerged and reworked while a new headland was created at the site of active fluvial sediment input. Historic-period levees have decoupled the delta plain from its fluvial sediment source at the same time global sea-level rise was accelerating, which has accelerated delta-plain submergence. Diversions of Mississippi River water and sediment are necessary to achieve delta plain sustainability, but upstream dams trap ˜50% of the total sediment load, and there is not enough supply to keep pace with subsidence and accelerated sea-level rise. The future delta region will not resemble the recent past, and significant drowning is inevitable.

  7. Ancient deltas on Mars: outstanding targets for martian habitability?

    NASA Astrophysics Data System (ADS)

    Gupta, S.; Fawdon, P.; Grindrod, P. M.; Balme, M. R.; Hauber, E.; Warner, N. H.; Muller, J. P.

    2014-12-01

    The identification of putative ancient deltaic sedimentary systems on Mars has been both exciting and controversial. Our excitement is elicted by the potential provided by deltas as evidence for standing bodies of water associated with the deltas, and the resulting implications for both the ancient climate of Mars and ancient habitability. The controversy stems from how confident can we be in the identification of ancient deltaic systems from orbital data, and how robust are our assertions about the habitability potential of such settings. Delta systems in particular are key astrobiological targets because at their distal toes fine-grained sediment (ie., clays) settle from suspension in a lower energy setting and they are commonly characterised by high rates of sedimentation. This leads to high preservation potential of biosignatures. Targeting of future Mars rovers to investigate deltaic landing sites requires better understanding of these issues to reduce exploration risk. In this presentation, we describe the key criteria that enable us to make robust interpretations of deltaic stratigraphy and constrain delta evolution for martian systems. In particular, the past 10 years has seen in a revolution in our process understanding of terrestrial delta systems through a combination of field, experimental and numerical modelling studies. Analysis of martian deltas has much to gain from these results. We go on to consider why deltaic systems offer potential as astrobiological target paleoenvironments. We use the exhumed delta system (Hypanis delta system) at the termination of Hypanis Vallis, 11.8°N, 314.96°E as a case example. This system, situated in Xanthe Terra, comprises layered sedimentary rocks with an overall multi-lobate geometry and associated inverted channel networks. The Hypanis 'delta' is a proposed landing site for the ExoMars rover and also for the NASA 2020 mission.

  8. Delta-conotoxin structure/function through a cladistic analysis.

    PubMed

    Bulaj, G; DeLaCruz, R; Azimi-Zonooz, A; West, P; Watkins, M; Yoshikami, D; Olivera, B M

    2001-11-01

    Delta-conotoxins are Conus peptides that inhibit inactivation of voltage-gated sodium channels. The suggestion that delta-conotoxins might be an essential component of the venoms of fish-hunting cone snails which rapidly immobilize their prey [Terlau, H., Shon, K., Grilley, M., Stocker, M., Stühmer, W., and Olivera, B. M. (1996) Nature 381, 148-151] has not been tested. On the basis of cDNA cloning, all of the fish-hunting Conus analyzed yielded at least one delta-conotoxin sequence. In addition, one delta-conotoxin isolated from the venom of Conus striatus had an amino acid sequence identical to that predicted from cDNA cloning. This new peptide exhibited properties of delta-conotoxins: it targeted sodium channels and potentiated action potentials by slowing channel inactivation. Homologous sequences of delta-conotoxins from two groups (clades) of related fish-hunting Conus species share consensus features but differ significantly from the two known delta-conotoxins from mollusc-hunting Conus venoms. Three large hydrophobic amino acids were conserved; analogues of the previously described delta-conotoxin PVIA with alanine substituted for the conserved amino acids F9 and I12 lost substantial biological activity. In contrast, both the T8A and K13A delta-conotoxin PVIA analogues, where substitutions were at nonconserved loci, proved to be biologically active. Taken together, our results indicate that a cladistic approach can identify amino acids critical for the activity of conotoxins and provide extensive information as to which amino acid substitutions can be made without significant functional consequences.

  9. Including the {delta}(1232) resonance in baryon chiral perturbation theory

    SciTech Connect

    Hacker, C.; Wies, N.; Scherer, S.; Gegelia, J.

    2005-11-01

    Baryon chiral perturbation theory with explicit {delta}(1232) degrees of freedom is considered. The most general interactions of pions, nucleons, and {delta} consistent with all underlying symmetries as well as with the constraint structure of higher-spin fields are constructed. By use of the extended on-mass-shell renormalization scheme, a manifestly Lorentz-invariant effective-field theory with a systematic power counting is obtained. As applications, we discuss the mass of the nucleon, the pion-nucleon {sigma} term, and the pole of the {delta} propagator.

  10. Holocene evolution of the western Orinoco Delta, Venezuela

    USGS Publications Warehouse

    Aslan, A.; White, W.A.; Warne, A.G.; Guevara, E.H.

    2003-01-01

    The pristine nature of the Orinoco Delta of eastern Venezuela provides unique opportunities to study the geologic processes and environments of a major tropical delta. Remote-sensing images, shallow cores, and radiocarbon-dating of organic remains form the basis for describing deltaic environments and interpreting the Holocene history of the delta. The Orinoco Delta can be subdivided into two major sectors. The southeast sector is dominated by the Rio Grande-the principal distributary-and complex networks of anastomosing fluvial and tidal channels. The abundance of siliciclastic deposits suggests that fluvial processes such as over-bank flooding strongly influence this part of the delta. In contrast, the northwest sector is represented by few major distributaries, and overbank sedimentation is less widespread relative to the southeast sector. Peat is abundant and occurs in herbaceous and forested swamps that are individually up to 200 km2 in area. Northwest-directed littoral currents transport large volumes of suspended sediment and produce prominent mudcapes along the northwest coast. Mapping of surface sediments, vegetation, and major landforms identified four principal geomorphic systems within the western delta plain: (1) distributary channels, (2) interdistributary flood basins, (3) fluvial-marine transitional environments, and (4) marine-influenced coastal environments. Coring and radiocarbon dating of deltaic deposits show that the northern delta shoreline has prograded 20-30 km during the late Holocene sea-level highstand. Progradation has been accomplished by a combination of distributary avulsion and mudcape progradation. This style of deltaic progradation differs markedly from other deltas such as the Mississippi where distributary avulsion leads to coastal land loss, rather than shoreline progradation. The key difference is that the Orinoco Delta coastal zone receives prodigious amounts of sediment from northwest-moving littoral currents that transport

  11. Late quaternary evolution of the Orinoco Delta, Venezuela

    USGS Publications Warehouse

    Warne, A.G.; Guevara, E.H.; Aslan, A.

    2002-01-01

    The modern Orinoco Delta is the latest of a series of stacked deltas that have infilled the Eastern Venezuelan Basin (EVB) since the Oligocene. During the late Pleistocene sea-level lowstand (20,000 to 16,000 yrs BP), bedrock control points at the position of the present delta apex prevented the river channel from incising as deeply as many other major river systems. Shallow seismic data indicate that the late Pleistocene Orinoco incised into the present continental shelf, where it formed a braided-river complex that transported sediment to a series of shelf-edge deltas. As sea level rose from 16,000 to 9,500 yrs BP, the Orinoco shoreline shifted rapidly landward, causing shallow-marine waves and currents to form a widespread transgressive sand unit. Decelerating sea-level rise and a warmer, wetter climate during the early Holocene (9,500 to 6,000 yrs BP) induced delta development within the relatively quiet-water environment of the EVB embayment. Sea level approached its present stand in the middle Holocene (6,000 to 3,000 yrs BP), and the Orinoco coast prograded, broadening the delta plain and infilling the EVB embayment. Significant quantities of Amazon sediment began to be transported to the Orinoco coast by littoral currents. Continued progradation in the late Holocene caused the constriction at Boca de Serpientes to alter nearshore and shelf hydrodynamics and subdivide the submarine delta into two distinct areas: the Atlantic shelf and the Gulf of Paria. The increased influence of littoral currents along the coast promoted mudcape development. Because most of the water and sediment were transported across the delta plain through the Rio Grande distributary in the southern delta, much of the central and northwestern delta plain became sediment starved, promoting widespread accumulation of peat deposits. Human impacts on the delta are mostly associated with the Volca??n Dam on Can??o Manamo. However, human activities have had relatively little effect on the

  12. Verification of Software Product Lines with Delta-Oriented Slicing

    NASA Astrophysics Data System (ADS)

    Bruns, Daniel; Klebanov, Vladimir; Schaefer, Ina

    Software product line (SPL) engineering is a well-known approach to develop industry-size adaptable software systems. SPL are often used in domains where high-quality software is desirable; the overwhelming product diversity, however, remains a challenge for assuring correctness. In this paper, we present delta-oriented slicing, an approach to reduce the deductive verification effort across an SPL where individual products are Java programs and their relations are described by deltas. On the specification side, we extend the delta language to deal with formal specifications. On the verification side, we combine proof slicing and similarity-guided proof reuse to ease the verification process.

  13. Altamaha River Delta, Georgia Sea Islands

    NASA Technical Reports Server (NTRS)

    2001-01-01

    The history of sea islands in the Altamaha River delta on the coast of Georgia is revealed in this image produced from data acquired by the Airborne Synthetic Aperture Radar (AIRSAR), developed and operated by NASA's Jet Propulsion Laboratory, Pasadena, Calif. The outlines of long-lost plantation rice fields, canals, dikes and other inlets are clearly defined. Salt marshes are shown in red, while dense cypress and live oak tree canopies are seen in yellow-greens.

    Agricultural development of the Altamaha delta began soon after the founding of the Georgia Colony in 1733. About 25 plantations were located on the low-lying islands and shores by the 19th century, taking advantage of the rich alluvial flow and annual inundation of water required by some crops. The first major crop was indigo; when demand for that faded, rice and cotton took its place. A major storm in 1824 destroyed much of the town of Darien (upper right) and put many of the islands under 20 feet of water. The Civil War ended the plantation system, and many of the island plantations disappeared under heavy brush and new growth pine forests. Some were used as tree farms for paper and pulp industries, while the Butler Island (center left) plantation became a wildlife conservation site growing wild sea rice for migrating ducks and other waterfowl. Margaret Mitchell is reputed to have used the former owner of the Butler Plantation as a basis for the Rhett Butler character in her novel 'Gone With The Wind,' taking the first name from Rhett's Island (lower right).

    These data were obtained during a 1994-95 campaign along the Georgia coast. AIRSAR's ability to detect vegetation canopy density, hydrological features and other topographic characteristics is a useful tool in landscape archaeology. AIRSAR flies aboard a NASA DC-8 based at NASA's Dryden Flight Research Center, Edwards, Calif. The analysis on the data shown was accomplished by Dr. Gary Mckay, Department of Archaeology and Geography, and Ian

  14. Volga Delta and the Caspian Sea

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Russia's Volga River is the largest river system in Europe, draining over 1.3 million square kilometers of catchment area into the Caspian Sea. The brackish Caspian is Earth's largest landlocked water body, and its isolation from the world's oceans has enabled the preservation of several unique animal and plant species. The Volga provides most of the Caspian's fresh water and nutrients, and also discharges large amounts of sediment and industrial waste into the relatively shallow northern part of the sea. These images of the region were captured by the Multi-angle Imaging SpectroRadiometer on October 5, 2001, during Terra orbit 9567. Each image represents an area of approximately 275 kilometers x 376 kilometers.

    The left-hand image is from MISR's nadir (vertical-viewing) camera, and shows how light is reflected at red, green, and blue wavelengths. The right-hand image is a false color composite of red-band imagery from MISR's 60-degree backward, nadir, and 60-degree forward-viewing cameras, displayed as red, green, and blue, respectively. Here, color variations indicate how light is reflected at different angles of view. Water appears blue in the right-hand image, for example, because sun glitter makes smooth, wet surfaces look brighter at the forward camera's view angle. The rougher-textured vegetated wetlands near the coast exhibit preferential backscattering, and consequently appear reddish. A small cloud near the center of the delta separates into red, green, and blue components due to geometric parallax associated with its elevation above the surface.

    Other notable features within the images include several linear features located near the Volga Delta shoreline. These long, thin lines are artificially maintained shipping channels, dredged to depths of at least 2 meters. The crescent-shaped Kulaly Island, also known as Seal Island, is visible near the right-hand edge of the images.

    MISR was built and is managed by NASA's Jet Propulsion Laboratory

  15. Birds' tails do act like delta wings but delta-wing theory does not always predict the forces they generate.

    PubMed Central

    Evans, Matthew R

    2003-01-01

    Delta-wing theory, which predicts the aerodynamics of aircraft like the Concorde, is the conventional explanation for the way in which a bird's tail operates in flight. Recently, doubt has been cast on the validity of applying a theory devised for supersonic aircraft to the small tails of slow-flying birds. By testing delta-wing models and birds' tails behind bodies with wings, I empirically show that the tails of birds produce lift in a very similar way to conventional delta-wing models. Both Perspex and birds' tail models produce lift similar to that predicted by delta-wing theory when narrowly spread and at low angles of attack. However, when widely spread and at high angles of attack, both tails and Perspex models produce much less lift than predicted, owing to vortex breakdown after which the assumptions of delta-wing theory are violated. These results indicate that birds' tails can be regarded as delta wings but that the theory predicting the forces produced by delta wings can only be applied within acceptable limits (i.e. tails spread less than 60 degrees and at angles of attack of less than 20 degrees). PMID:12965029

  16. The ISAS Synchrotron Microprobe at DELTA

    SciTech Connect

    Bohlen, Alex von; Kraemer, Markus; Hergenroeder, Roland; Berges, Ulf

    2007-01-19

    Since 2004 ISAS operates a dipole beamline at the synchrotron radiation facility DELTA at University of Dortmund. Synchrotron radiation is used at this beamline as an excellent excitation source for X-ray fluorescence spectrometry (XRF). Among others, the high brilliance of the synchrotron radiation in contrast to conventional X-ray tubes, the strong polarization of the synchrotron radiation and the low divergence of the electron beam can be applied to XRF offering several advantages for spectroscopy. These outstanding features encouraged us to develop and operate a synchrotron radiation induced X-ray micro fluorescence probe connected to a wavelength dispersive spectrometer (SR-WDXRF). A relevant characteristic of such a device, namely, good lateral resolution at high spectral resolution can be applied for single spot-, line-scan and area map analyses of a variety of objects. The instrumentation of the SR-WDXRF and the performed experiments will be presented. Main task is the detection of light elements by their fluorescence K-lines and the specification of element compounds.

  17. Status of the Synchrotron Light Source DELTA

    SciTech Connect

    Berges, U.; Sternemann, C.; Tolan, M.; Westphal, C.; Weis, T.; Wille, K.

    2007-01-19

    The Dortmund Electron Accelerator DELTA, a 1.5 GeV synchrotron light source located at University of Dortmund, is operated for 3000 h per year including 2000 h beam time for synchrotron radiation use and 1000 h for machine physics, optimisation and maintenance. The status of the synchrotron light source is presented with emphasis on the operation, commissioning and installation of beamlines and insertion devices. The soft X-ray undulator beamlines provide photon energies between 5 to 400 eV (U250) and 55 and 1500 eV (U55), respectively. One dipole beamline covers soft X-rays between 6 to 200 eV, and a second dipole beamline is used without a monochromator at 2.2 keV critical energy of the dipole spectrum. For photons in the hard X-ray regime, a superconducting asymmetric wiggler (SAW) with a field of 5.3 T and 7.9 keV critical energy was installed, providing circularly polarized X-rays in the range of 2 to 30 keV. Due to its broad radiation fan, three beamlines are simultaneously served. The first SAW-beamline with an energy range between 4 to 30 keV is in full operation, the second is under commissioning, serving the energy range between 2 to 30 keV. The third SAW beamline is near completion, additional dipole beamlines are under construction.

  18. Theoretical studies on flapped delta wings

    NASA Technical Reports Server (NTRS)

    Oh, S.; Tavella, D.; Roberts, L.

    1988-01-01

    The effects of leading edge flaps on the aerodynamic characteristics of a low aspect-ratio delta wing are studied theoretically. As an extension of the classical crossflow plane analysis and in order to include separated shear layers, an analogy between three dimensional steady conical and two dimensional unsteady self-similar flows is explored. This analogy provides a simple steady-unsteady relationship. The criteria for the validity of the steady-unsteady analogy are also examined. Two different theoretical techniques are used to represent the separated shear layers based on the steady-unsteady analogy, neglecting the trailing edge effect. In the first approach, each vortex system is represented by a pair of concentrated vortices connected to the separation points by straight feeding sheets. In the second approach, the vortex cloud method is adopted for simulating the flow field in the crossflow plane. The separated shear layers are replaced with a cloud of discrete vortices and the boundary element method is employed to represent the wing trace by a vorticity distribution. A simple merging scheme is used to model the core region of the vortical flow as a single vortex by imposing a restriction on the shear layer rotation angle. The results are compared with experiments and with results from 3-D panel calculations.

  19. The hepatitis delta virus: Replication and pathogenesis.

    PubMed

    Sureau, Camille; Negro, Francesco

    2016-04-01

    Hepatitis delta virus (HDV) is a defective virus and a satellite of the hepatitis B virus (HBV). Its RNA genome is unique among animal viruses, but it shares common features with some plant viroids, including a replication mechanism that uses a host RNA polymerase. In infected cells, HDV genome replication and formation of a nucleocapsid-like ribonucleoprotein (RNP) are independent of HBV. But the RNP cannot exit, and therefore propagate, in the absence of HBV, as the latter supplies the propagation mechanism, from coating the HDV RNP with the HBV envelope proteins for cell egress to delivery of the HDV virions to the human hepatocyte target. HDV is therefore an obligate satellite of HBV; it infects humans either concomitantly with HBV or after HBV infection. HDV affects an estimated 15 to 20 million individuals worldwide, and the clinical significance of HDV infection is more severe forms of viral hepatitis--acute or chronic--, and a higher risk of developing cirrhosis and hepatocellular carcinoma in comparison to HBV monoinfection. This review covers molecular aspects of HDV replication cycle, including its interaction with the helper HBV and the pathogenesis of infection in humans. PMID:27084031

  20. BSM Delta Qualification 2, volume 2

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This report, presented in three volumes, provides the results of a two-motor Delta Qualification 2 program conducted in 1993 to certify the following enhancements for incorporation into booster separation motor (BSM) flight hardware: vulcanized-in-place nozzle aft closure insulation; new iso-static ATJ bulk graphite throat insert material; adhesive EA 9394 for bonding the nozzle throat, igniter grain rod/centering insert/igniter case; deletion of the igniter adapter insulator ring; deletion of the igniter adapter/igniter case interface RTV; and deletion of loctite from igniter retainer plate threads. The enhancements above directly resulted from (1) the BSM total quality management (TQM) team initiatives to enhance the BSM producibility, and (2) the necessity to qualify new throat insert and adhesive systems to replace existing materials that will not be available. Testing was completed at both the component and motor levels. Component testing was accomplished to screen candidate materials (e.g., throat materials, adhesive systems) and to optimize processes (e.g., aft closure insulator vulcanization approach) prior to their incorporation into the test motors. Motor tests -- consisting of two motors, randomly selected by USBI's on-site quality personnel from production lot AAY, which were modified to accept the enhancements -- were completed to provide the final qualification of the enhancements for incorporation into flight hardware. Volume 2 details the environmental testing (vibration and shock) conducted at Marshall Space Flight Center (MSFC) to which the motors were subjected prior to static tests.

  1. Delta 2 Explosion Plume Analysis Report

    NASA Technical Reports Server (NTRS)

    Evans, Randolph J.

    2000-01-01

    A Delta II rocket exploded seconds after liftoff from Cape Canaveral Air Force Station (CCAFS) on 17 January 1997. The cloud produced by the explosion provided an opportunity to evaluate the models which are used to track potentially toxic dispersing plumes and clouds at CCAFS. The primary goal of this project was to conduct a case study of the dispersing cloud and the models used to predict the dispersion resulting from the explosion. The case study was conducted by comparing mesoscale and dispersion model results with available meteorological and plume observations. This study was funded by KSC under Applied Meteorology Unit (AMU) option hours. The models used in the study are part of the Eastern Range Dispersion Assessment System (ERDAS) and include the Regional Atmospheric Modeling System (RAMS), HYbrid Particle And Concentration Transport (HYPACT), and Rocket Exhaust Effluent Dispersion Model (REEDM). The primary observations used for explosion cloud verification of the study were from the National Weather Service's Weather Surveillance Radar 1988-Doppler (WSR-88D). Radar reflectivity measurements of the resulting cloud provided good estimates of the location and dimensions of the cloud over a four-hour period after the explosion. The results indicated that RAMS and HYPACT models performed reasonably well. Future upgrades to ERDAS are recommended.

  2. Forests fuel fish growth in freshwater deltas

    PubMed Central

    Tanentzap, Andrew J.; Szkokan-Emilson, Erik J.; Kielstra, Brian W.; Arts, Michael T.; Yan, Norman D.; Gunn, John M.

    2014-01-01

    Aquatic ecosystems are fuelled by biogeochemical inputs from surrounding lands and within-lake primary production. Disturbances that change these inputs may affect how aquatic ecosystems function and deliver services vital to humans. Here we test, using a forest cover gradient across eight separate catchments, whether disturbances that remove terrestrial biomass lower organic matter inputs into freshwater lakes, thereby reducing food web productivity. We focus on deltas formed at the stream-lake interface where terrestrial-derived particulate material is deposited. We find that organic matter export increases from more forested catchments, enhancing bacterial biomass. This transfers energy upwards through communities of heavier zooplankton, leading to a fourfold increase in weights of planktivorous young-of-the-year fish. At least 34% of fish biomass is supported by terrestrial primary production, increasing to 66% with greater forest cover. Habitat tracers confirm fish were closely associated with individual catchments, demonstrating that watershed protection and restoration increase biomass in critical life-stages of fish. PMID:24915965

  3. BSM Delta qualification 2, volume 1

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This report, presented in three volumes, provides the results of a two-motor Delta Qualification 2 program conducted in 1993 to certify the following enhancements for incorporation into Booster Separation Motor (BSM) flight hardware: (1) vulcanized-in-place nozzle aft closure insulation; (2) new isostatic ATJ bulk graphite throat insert material; (3) adhesive EA 9394 for bonding the nozzle throat, igniter grain rod/centering insert/igniter case; (4) deletion of the igniter adapter insulator ring; (5) deletion of igniter adapter/igniter case interface RTV; and (6) deletion of Loctite from igniter retainer plate threads. The enhancements above directly resulted from (1) the BSM Total Quality Management (TQM) Team initiatives to enhance the BSM producibility, and (2) the necessity to qualify new throat insert and adhesive systems to replace existing materials that will not be available. Testing was completed at both the component and motor levels. Component testing was accomplished to screen candidate materials (e.g., throat materials, adhesive systems) and to optimize processes (e.g., aft closure insulator vulcanization approach) prior to their incorporation into the test motors. Motor testing - consisting of two motors, randomly selected by USBI's onsite quality personnel from production lot AAY, which were modified to accept the enhancements - were completed to provide the final qualification of the enhancements for incorporation into flight hardware. It is concluded that all of the enhancements herein tested are qualified to be incorporated into flight hardware for the BSM.

  4. Forests fuel fish growth in freshwater deltas.

    PubMed

    Tanentzap, Andrew J; Szkokan-Emilson, Erik J; Kielstra, Brian W; Arts, Michael T; Yan, Norman D; Gunn, John M

    2014-01-01

    Aquatic ecosystems are fuelled by biogeochemical inputs from surrounding lands and within-lake primary production. Disturbances that change these inputs may affect how aquatic ecosystems function and deliver services vital to humans. Here we test, using a forest cover gradient across eight separate catchments, whether disturbances that remove terrestrial biomass lower organic matter inputs into freshwater lakes, thereby reducing food web productivity. We focus on deltas formed at the stream-lake interface where terrestrial-derived particulate material is deposited. We find that organic matter export increases from more forested catchments, enhancing bacterial biomass. This transfers energy upwards through communities of heavier zooplankton, leading to a fourfold increase in weights of planktivorous young-of-the-year fish. At least 34% of fish biomass is supported by terrestrial primary production, increasing to 66% with greater forest cover. Habitat tracers confirm fish were closely associated with individual catchments, demonstrating that watershed protection and restoration increase biomass in critical life-stages of fish. PMID:24915965

  5. The DELTA 181 lithium thionyl chloride battery

    NASA Astrophysics Data System (ADS)

    Sullivan, Ralph M.; Brown, Lawrence E.; Leigh, A. P.

    In 1986, the Johns Hopkins University/Applied Physics Laboratory (JHU/APL) undertook the development of a sensor module for the DELTA 181 spacecraft, a low earth orbit (LEO) mission of less than two months duration. A large lithium thionyl chloride battery was developed as the spacecraft's primary power source, the first known such use for this technology. The exceptionally high energy density of the lithium thionyl chloride cell was the primary driver for its use, resulting in a completed battery with a specific energy density of 120 Wh/lb. Safety requirements became the primary driver shaping all aspects of the power system design and development due to concerns about the potential hazards of this relatively new, high-energy technology. However, the program was completed without incident. The spacecraft was launched on February 8, 1988, from Kennedy Space Center (KSC) with over 60,000 Wh of battery energy. It reentered on April 2, 1988, still operating after 55 days, providing a successful, practical, and visible demonstration of the use of this technology for spacecraft applications.

  6. BSM Delta qualification 2, volume 1

    NASA Astrophysics Data System (ADS)

    1994-11-01

    This report, presented in three volumes, provides the results of a two-motor Delta Qualification 2 program conducted in 1993 to certify the following enhancements for incorporation into Booster Separation Motor (BSM) flight hardware: (1) vulcanized-in-place nozzle aft closure insulation; (2) new isostatic ATJ bulk graphite throat insert material; (3) adhesive EA 9394 for bonding the nozzle throat, igniter grain rod/centering insert/igniter case; (4) deletion of the igniter adapter insulator ring; (5) deletion of igniter adapter/igniter case interface RTV; and (6) deletion of Loctite from igniter retainer plate threads. The enhancements above directly resulted from (1) the BSM Total Quality Management (TQM) Team initiatives to enhance the BSM producibility, and (2) the necessity to qualify new throat insert and adhesive systems to replace existing materials that will not be available. Testing was completed at both the component and motor levels. Component testing was accomplished to screen candidate materials (e.g., throat materials, adhesive systems) and to optimize processes (e.g., aft closure insulator vulcanization approach) prior to their incorporation into the test motors. Motor testing - consisting of two motors, randomly selected by USBI's onsite quality personnel from production lot AAY, which were modified to accept the enhancements - were completed to provide the final qualification of the enhancements for incorporation into flight hardware. It is concluded that all of the enhancements herein tested are qualified to be incorporated into flight hardware for the BSM.

  7. BSM Delta Qualification 2, volume 2

    NASA Astrophysics Data System (ADS)

    1994-11-01

    This report, presented in three volumes, provides the results of a two-motor Delta Qualification 2 program conducted in 1993 to certify the following enhancements for incorporation into booster separation motor (BSM) flight hardware: vulcanized-in-place nozzle aft closure insulation; new iso-static ATJ bulk graphite throat insert material; adhesive EA 9394 for bonding the nozzle throat, igniter grain rod/centering insert/igniter case; deletion of the igniter adapter insulator ring; deletion of the igniter adapter/igniter case interface RTV; and deletion of loctite from igniter retainer plate threads. The enhancements above directly resulted from (1) the BSM total quality management (TQM) team initiatives to enhance the BSM producibility, and (2) the necessity to qualify new throat insert and adhesive systems to replace existing materials that will not be available. Testing was completed at both the component and motor levels. Component testing was accomplished to screen candidate materials (e.g., throat materials, adhesive systems) and to optimize processes (e.g., aft closure insulator vulcanization approach) prior to their incorporation into the test motors. Motor tests -- consisting of two motors, randomly selected by USBI's on-site quality personnel from production lot AAY, which were modified to accept the enhancements -- were completed to provide the final qualification of the enhancements for incorporation into flight hardware. Volume 2 details the environmental testing (vibration and shock) conducted at Marshall Space Flight Center (MSFC) to which the motors were subjected prior to static tests.

  8. Delta Morphodynamics Matters! Ecosystem Services, Poverty and Morphodynamic Change in the Ganges-Brahmaputra Mega-Delta

    NASA Astrophysics Data System (ADS)

    Nicholls, R. J.; Adger, N.; Allan, A.; Darby, S. E.; Hutton, C.; Matthews, Z.; Rahman, M.; Whitehead, P. G.; Wolf, J.

    2013-12-01

    The world's deltas are probably the most vulnerable type of coastal environment, and they face multiple stresses in the coming decades. These stresses include, amongst others, local drivers due to land subsidence, population growth and urbanisation within the deltas, regional drivers due to changes in catchment management (e.g. upstream land use and dam construction), as well as global climate change impacts such as sea-level rise. At the same time, the ecosystem services of river deltas support high population densities, with around 14% of the global population inhabiting deltas. A large proportion of these people experience extremes of poverty and they are therefore severely exposed to vulnerability from environmental and ecological stress and degradation. In areas close to or below the poverty boundary, both subsistence and cash elements of the economy tend to rely disproportionately heavily on ecosystem services which underpin livelihoods. Therefore, to sustainably manage delta environments they must be viewed as complex social-environmental systems where change is only partially driven by physical drivers such as sea level rise and climate change, and human-induced development activities are also critical. Here we outline a new conceptual framework for the development of methods to understand and characterise the key drivers of change in ecosystem services that affect the environment and economic status of populous deltas, focusing specifically on the Ganges-Brahmaputra-Meghna (GBM) mega-delta. The GBM delta is characterised by densely populated coastal lowlands with significant poverty, with livelihoods supported to a large extent by natural ecosystems such as the Sunderbahns (the largest mangrove forest in the world). However, the GBM delta is under severe development pressure due to many growing cities. At present the importance of ecosystems services to poverty and livelihoods is poorly understood. This is due to due to the complexity of interactions

  9. The late-Holocene progradation of the Mahakam Delta, Indonesia - A case study of tidal, tropical deltas

    NASA Astrophysics Data System (ADS)

    Dalman, R.; Ranawijaya, D.; Missiaen, T.; Kroonenberg, S.; Storms, J.

    2011-12-01

    The Mahakam Delta is an oft-cited example of a mixed fluvial-tidally influenced delta. Yet the distinct separation of the tide-dominated delta plain and the fluvial distributaries make the delta unique amongst tidally influenced deltas. The delta prograded an average of 60 km over the last 5000 years. Most sediment transport is induced by tidal currents and fluvial discharge, which resulted in a distinct, dense network of distributary and tidal channels. In order to characterize the Holocene sedimentary architecture we describe a dataset of 10 new cores and a large survey of very high-resolution, shallow seismics. The seismics are recorded using an echosounder with a novel parametric source, allowing subsurface penetration in excess of 15 m while achieving a vertical resolution of 0.2 m. Distinct sedimentary facies are described in detail for delta plain, delta front, distributary and mouthbar deposits. A notable difference in stratal pattern has been observed between the inner and outer tide-dominated delta plain facies. The inner tidal channels cut deeply into the underlying deltafront deposits and form a distinct heterogenic laterally accreting and intercutting facies. Whereas the outer tide-dominated delta plain deposits accrete conformably on the marine deltafront facies and show a much more homogenous sedimentary architecture. The continual reworking of the inner tide-dominated delta plain results in a patchwork of deposits greatly varying in thickness and age albeit with a similar silty clay lithology. The area of the present-day delta was largely flooded after the early to mid-Holocene transgression, our data indicate that a small branch of fluvial distributaries was active on the current delta plain around 5 ka. Subsequently, the northernmost fluvial distributary built out rapidly over a period of 3 kyrs. The southern distributaries built out later, from 2 ka to the present. The mouthbar deposits in the south are significantly thicker than in the northern

  10. Morphologic and stratigraphic evolution of muddy ebb-tidal deltas along a subsiding coast: Barataria Bay, Mississippi River delta

    USGS Publications Warehouse

    FitzGerald, D.M.; Kulp, M.; Penland, S.; Flocks, J.; Kindinger, J.

    2004-01-01

    The Barataria barrier coast formed between two major distributaries of the Mississippi River delta: the Plaquemines deltaic headland to the east and the Lafourche deltaic headland to the west. Rapid relative sea-level rise (1??03 cm year-1) and other erosional processes within Barataria Bay have led to substantial increases in the area of open water (> 775 km2 since 1956) and the attendant bay tidal prism. Historically, the increase in tidal discharge at inlets has produced larger channel cross-sections and prograding ebb-tidal deltas. For example, the ebb delta at Barataria Pass has built seaward > 2??2 km since the 1880s. Shoreline erosion and an increasing bay tidal prism also facilitated the formation of new inlets. Four major lithofacies characterize the Barataria coast ebb-tidal deltas and associated sedimentary environments. These include a proximal delta facies composed of massive to laminated, fine grey-brown to pale yellow sand and a distal delta facies consisting of thinly laminated, grey to pale yellow sand and silty sand with mud layers. The higher energy proximal delta deposits contain a greater percentage of sand (75-100%) compared with the distal delta sediments (60-80%). Associated sedimentary units include a nearshore facies consisting of horizontally laminated, fine to very fine grey sand with mud layers and an offshore facies that is composed of grey to dark grey, laminated sandy silt to silty clay. All facies coarsen upwards except the offshore facies, which fines upwards. An evolutionary model is presented for the stratigraphic development of the ebb-tidal deltas in a regime of increasing tidal energy resulting from coastal land loss and tidal prism growth. Ebb-tidal delta facies prograde over nearshore sediments, which interfinger with offshore facies. The seaward decrease in tidal current velocity of the ebb discharge produces a gradational contact between proximal and distal tidal delta facies. As the tidal discharge increases and the inlet

  11. Analysis and design for delta operator systems with actuator saturation

    NASA Astrophysics Data System (ADS)

    Yang, Hongjiu; Shi, Peng; Li, Zhiwei; Hua, Changchun

    2014-05-01

    This paper studies the problem of estimating the domain of attraction for delta operator systems under a pre-designed saturated linear feedback. Ellipsoids are used as the estimates of domain of attraction for delta operator systems. A condition is derived in terms of an auxiliary feedback matrix for determining if a given ellipsoid is contractive invariant. Moreover, some necessary and sufficient conditions are given for single input delta operator systems. The results are also further extended to determine the invariant sets for delta operator systems with persistent disturbances. Linear matrix inequalities based on the methods are developed for constructing feedback laws that achieve disturbance rejection with guaranteed stability requirements. Some numerical examples are given to illustrate the effectiveness of the developed techniques.

  12. 23. OWENS RIVER DELTA JUST NORTH OF CROWLEY LAKE ...

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

    23. OWENS RIVER DELTA JUST NORTH OF CROWLEY LAKE - Los Angeles Aqueduct, From Lee Vining Intake (Mammoth Lakes) to Van Norman Reservoir Complex (San Fernando Valley), Los Angeles, Los Angeles County, CA

  13. A variable-step-size robust delta modulator.

    NASA Technical Reports Server (NTRS)

    Song, C. L.; Garodnick, J.; Schilling, D. L.

    1971-01-01

    Description of an analytically obtained optimum adaptive delta modulator-demodulator configuration. The device utilizes two past samples to obtain a step size which minimizes the mean square error for a Markov-Gaussian source. The optimum system is compared, using computer simulations, with a linear delta modulator and an enhanced Abate delta modulator. In addition, the performance is compared to the rate distortion bound for a Markov source. It is shown that the optimum delta modulator is neither quantization nor slope-overload limited. The highly nonlinear equations obtained for the optimum transmitter and receiver are approximated by piecewise-linear equations in order to obtain system equations which can be transformed into hardware. The derivation of the experimental system is presented.

  14. Delta-doped imagers for UV and EUV applications

    NASA Technical Reports Server (NTRS)

    Nikzad, S.; Jones, T. J.; Cunningham, T. J.; Deelman, P. W.; Elliot, S. T.

    2000-01-01

    In this paper we will discuss performance of delta-doped CCDs in UV and EUV, our in-house thinning capability, bonding approaches for producing flat focal plane arrays, and in-house capabilities of directly applied antireflection coatings.

  15. Alternative Interpretation for the Eberswalde Delta, Holden NE Crater, Mars

    NASA Astrophysics Data System (ADS)

    Fedo, C. M.; Finkelstein, D. B.; Moersch, J. E.

    2008-03-01

    Examination of HiRISE images from the Eberswalde Delta reveal that it is hard to identify sedimentologic and stratigraphic components of a fluvio-deltaic system, leaving open alternative interpretations for the origin of the strata and geomorphpology.

  16. Aberrant accumulation of phospholipase C-delta in Alzheimer brains.

    PubMed Central

    Shimohama, S.; Homma, Y.; Suenaga, T.; Fujimoto, S.; Taniguchi, T.; Araki, W.; Yamaoka, Y.; Takenawa, T.; Kimura, J.

    1991-01-01

    Since phosphoinositide-specific phospholipase C (PLC) is one of the key molecules in signal transduction, the authors assessed its involvement in Alzheimer's disease (AD). Immunostaining of a specific antibody against the PLC isozyme, PLC-delta, demonstrated that this enzyme was abnormally accumulated in neurofibrillary tangles (NFT), the neurites surrounding senile plaque (SP) cores, and neuropil threads in AD brains. Western blot analysis confirmed that PLC-delta was concentrated in the paired helical filament (PHF)-rich fraction of AD brains. Antibodies to other PLC isozymes did not produce positive immunostaining of these pathologic structures. Moreover, diffuse and amorphous deposits of PLC-delta were found to precede the accumulation of fibrillary deposits. These results suggest that PLC-delta accumulation is a crucial event that ultimately may contribute to the formation of PHF. Images Figure 1 Figure 2 Figure 3 PMID:1928298

  17. Establishment report: Reforestation of the Pen Branch corridor and delta

    SciTech Connect

    Nelson, E.A.; Dulohery, N.J.; Bunton, C.S.; Trettin, C.C.; McKee, W.H. Jr.

    1995-12-01

    This report documents the role of the USDA Forest Service in the reforestation of the Pen Branch floodplain and delta. The report focuses upon the reforestation activities and monitoring to characterize the sites.

  18. Ecosystem Services Assessment of the Nemunas River Delta

    EPA Science Inventory

    The concept of ecosystem services recognizes the services, and benefits, provided to people by ecosystems. The Nemunas River Delta, in Lithuania, provides many ecosystem services to the people of the area, including food, fuel, transportation, climate regulation, water purificati...

  19. Quantification of sediment budgets at an arctic delta

    NASA Astrophysics Data System (ADS)

    Kroon, A.; Bendixen, M.; Sigsgaard, C.

    2012-12-01

    The impact of ice and snow and freezing temperatures make arctic polar coastal environments quite unique and different from other coastal environments for instance in temperate zones or in tropic areas. The coastal processes and the morphologic evolution of landforms in these areas are strongly influenced by common factors such as cold temperatures, (dis)continuous or sporadic permafrost, and the presence of sea ice cover. Most of these factors have a strong seasonality and the impact of classic coastal processes by waves and tides are often limited to the summer and early fall. Global climate changes induce a lot of changes along the arctic coasts. Sea-levels are rising due to an increased fresh water flux from the glaciers and land ice masses. At the same time, the ice coverage of the coastal waters decreases and the open water periods in summer extend. This might cause extra wave activity with higher erosion rates along many of the shorelines. Many fjords and open coastal stretches in North-East Greenland have deltas. The sources for the sediments for these deltas are located in the drainage basins of rivers that are fed by melting glaciers. These rivers drain pro-glacial and fluvial valleys and may also deliver additional sediment by eroding glacial and peri-glacial deposits in the present coastal plain. Minor sources of sediment transport towards the delta come from reworking of sediments on the delta slope, through lateral transport from the adjacent shores, and through stranded sediment-loaded ice out of the fjord. Losses of sediments occur through further fluvial sediment transport over the delta towards the fjord, or by reworking of delta fringes by coastal processes due to ice, waves and tides. Sandy spits and small barriers often fringe the shoreline of a delta. These features are typically formed and active in the ice-free periods when coastal processes by waves and drifting ice rework the delta front and adjacent coastal cliffs. In this presentation

  20. 31 CFR 1010.655 - Special measures against Banco Delta Asia.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 31 Money and Finance:Treasury 3 2013-07-01 2013-07-01 false Special measures against Banco Delta... Delta Asia. (a) Definitions. For purposes of this section: (1) Banco Delta Asia means all branches, offices, and subsidiaries of Banco Delta Asia operating in any jurisdiction, including its...

  1. 31 CFR 1010.655 - Special measures against Banco Delta Asia.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 31 Money and Finance:Treasury 3 2011-07-01 2011-07-01 false Special measures against Banco Delta... Delta Asia. (a) Definitions. For purposes of this section: (1) Banco Delta Asia means all branches, offices, and subsidiaries of Banco Delta Asia operating in any jurisdiction, including its...

  2. 31 CFR 1010.655 - Special measures against Banco Delta Asia.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 31 Money and Finance:Treasury 3 2012-07-01 2012-07-01 false Special measures against Banco Delta... Delta Asia. (a) Definitions. For purposes of this section: (1) Banco Delta Asia means all branches, offices, and subsidiaries of Banco Delta Asia operating in any jurisdiction, including its...

  3. 75 FR 2896 - Order of Suspension of Trading; East Delta Resources Corp.

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-19

    ... COMMISSION Order of Suspension of Trading; East Delta Resources Corp. January 13, 2010. It appears to the... securities of East Delta Resources Corp. (``East Delta'') because it has not filed any periodic reports since... protection of investors require a suspension of trading in the securities of East Delta. Therefore, it...

  4. 31 CFR 1010.655 - Special measures against Banco Delta Asia.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 31 Money and Finance:Treasury 3 2014-07-01 2014-07-01 false Special measures against Banco Delta... Delta Asia. (a) Definitions. For purposes of this section: (1) Banco Delta Asia means all branches, offices, and subsidiaries of Banco Delta Asia operating in any jurisdiction, including its...

  5. East Louisiana continental shelf sediments: a product of delta reworking

    USGS Publications Warehouse

    Brooks, Gregg R.; Kingdinger, Jack L.; Penland, Shea; Williams, S. Jeffress

    1995-01-01

    Data from 77 vibracores were integrated with 6,700 line-km of high- resolution seismic reflection profiles collected off the eastern Louisiana coast in the region of the St. Bernard Delta, the first of the Holocene highstand deltas of the Mississippi River. Seismic fades and sediment facies were integrated in order to establish the stratigraphic details within this relict delta. Results provide a regional geologic framework from which comparisons can be made with other areas. Holocene deposits in the study area overlie a heavily dissected surface interpreted to represent a lowstand erosional surface. Resting on this surface is a thin unit of relatively clean, quartz sand interpreted to have been deposited during early transgression. This unit is overlain by sediments of the St. Bernard Delta, a seaward-prograding, coarsening-upward wedge of sands and muds that contain vertically-stacked units of deltaic succession. Two or more prograding units separated by an unconformity, delineated from regional seismic profiles, may represent laterally shifting subdelta lobes. Surficial sediments consist of a thin unit of sands and muds derived from and reflecting the individual subenvirons of the underlying delta. Holocene inner-shelf development off eastern Louisiana has been controlled by relative sea-level rise and sediment supply. Sediment supply and deposition are a product of delta progradation and delta-lobe switching. The modern shelf configuration and surficial sediment distribution patterns reflect reworking of underlying deltaic deposits. The lack of modern sediment input helps to maintain the imprint of this ancient delta on the modern shelf surface.

  6. The Great Diversion: Danube Delta under Human Control (Invited)

    NASA Astrophysics Data System (ADS)

    Giosan, L.

    2009-12-01

    Many deltas around the world are suffering from sediment deficits that render them unstable to current and predicted rates of sea level rise. One solution proposed to alleviate the complete or partial drowning of such deltas is the use of river diversions to increase the quantity of sediment supplied to the delta plain to support marsh accretion. We examine the results of a half century old program of diversion in the Danube delta that led to the creation of an extensive diversion channel network akin in scope and size to a natural deltaic network. Danube’s importance as a shipping route increased after the Crimean War in the 1850s; the European Danube Commission was charged with maintaining the Sulina distributary as a shipping channel until 1940s. In the same period, several canals were dug to aid fishing in lakes and bring freshwater to brackish lagoons. After World War II, Communist authorities dramatically increased the number of canals for fishing, fish-farming and reed harvesting. New data on sedimentation rates and estimates of sediment fluxes suggest that the intensive canalization in the second half of the 20th Century led to increased sediment deposition that compensated the decreasing sediment discharge linked to damming within the internal fluvial part of the delta; however, the external marine delta has become increasingly sediment starved during the same interval. We emphasize the similarities and contrasts between the “human-controlled” and natural deltaic channel networks of the Danube delta and discuss the sustainability of the delta as a sediment budget problem within a sea level rise context.

  7. Towards the synthesis of new dideoxy delta-dicarbonyl heptoses.

    PubMed

    Pistarà, Venerando; Chiacchio, Maria Assunta; Corsaro, Antonino

    2010-07-01

    The preparation of a delta-dicarbonyl sugar thorough ring-opening, by a methoxymercuration-demercuration procedure, of a 5-spirocyclopropanated d-galactose derivative, is reported. This method constitutes a new route for the transformation of a hexose into new and interesting delta-dicarbonyl sugars, synthetic precursors of cyclitols, carba- and azasugars. Moreover this is, to our best knowledge, the first reported example of an elongation to a higher sugar starting from a spirocyclopropanated saccharide.

  8. Earthshots: Satellite images of environmental change – Ayeyarwady Delta, Myanmar

    USGS Publications Warehouse

    Adamson, Thomas

    2013-01-01

    The Ayeyarwady Delta—also called the Irrawaddy Delta—is a vast alluvial floodplain. The delta spans over 35,000 km2 (13,500 mi2) and was once home to an extensive tract of mangrove forests, but deforestation has changed the landscape. One scientific study estimated that the delta lost 1,685 km2 (651 mi2) from 1978 to 2011. This 40-year sequence of Landsat images shows the relatively rapid loss of mangrove forest.

  9. Sedimentation patterns in floodplains of the Mekong Delta - Vietnam

    NASA Astrophysics Data System (ADS)

    Van Manh, Nguyen; Merz, Bruno; Viet Dung, Nguyen; Apel, Heiko

    2013-04-01

    Quantification of floodplain sedimentation during the flood season in the Mekong Delta (MD) plays a very important role in the assessment of flood deposits for a sustainable agro-economic development. Recent studies on floodplain sedimentation in the region are restricted to small pilot sites because of the large extend of the Delta, and the complex channel. This research aims at a quantification of the sediment deposition in floodplains of the whole Mekong Delta, and to access the impacts of the upstream basin development on the sedimentation in the Delta quantitatively. To achieve this, a suspended sediment transport model is developed based on the quasi-2D hydrodynamic model of the whole Mekong Delta developed by Dung et al. (2011). The model is calibrated and validated using observed data derived from several sediment measurement campaigns in channel networks and floodplains. Measured sediment data and hydrodynamic model quantify the spatio-temporal variability of sediment depositions in different spatial units: individual dyke compartments, and the sub-regions Plain of Reeds, Long Xuyen Quadrangle and the area between Tien River and Hau River. It is shown that the distribution of sediment deposition over the delta is highly depended on the flood magnitude, that in turn drives the operation policy of flood control systems in floodplains of the Mekong Delta. Thus, the sedimentation distribution is influenced by the protection level of the dyke systems in place and the distance to the Tien River and Hau River, the main branches of the Mekong in the Delta. This corroborates the main findings derived from data analysis obtained from a small scale test site by Hung et al, (2011, 2012a). Moreover, the results obtained here underlines the importance of the main channels for the sediment transport into the floodplains, and the deposition rate in floodplains is strongly driven by the intake locations and the distance from these to the main channels as well.

  10. Temperature independent quantum well FET with delta channel doping

    NASA Technical Reports Server (NTRS)

    Young, P. G.; Mena, R. A.; Alterovitz, S. A.; Schacham, S. E.; Haugland, E. J.

    1992-01-01

    A temperature independent device is presented which uses a quantum well structure and delta doping within the channel. The device requires a high delta doping concentration within the channel to achieve a constant Hall mobility and carrier concentration across the temperature range 300-1.4 K. Transistors were RF tested using on-wafer probing and a constant G sub max and F sub max were measured over the temperature range 300-70 K.

  11. Analog Delta-Back-Propagation Neural-Network Circuitry

    NASA Technical Reports Server (NTRS)

    Eberhart, Silvio

    1990-01-01

    Changes in synapse weights due to circuit drifts suppressed. Proposed fully parallel analog version of electronic neural-network processor based on delta-back-propagation algorithm. Processor able to "learn" when provided with suitable combinations of inputs and enforced outputs. Includes programmable resistive memory elements (corresponding to synapses), conductances (synapse weights) adjusted during learning. Buffer amplifiers, summing circuits, and sample-and-hold circuits arranged in layers of electronic neurons in accordance with delta-back-propagation algorithm.

  12. Multifunction audio digitizer. [producing direct delta and pulse code modulation

    NASA Technical Reports Server (NTRS)

    Monford, L. G., Jr. (Inventor)

    1974-01-01

    An illustrative embodiment of the invention includes apparatus which simultaneously produces both direct delta modulation and pulse code modulation. An input signal, after amplification, is supplied to a window comparator which supplies a polarity control signal to gate the output of a clock to the appropriate input of a binary up-down counter. The control signals provide direct delta modulation while the up-down counter output provides pulse code modulation.

  13. A delta T-cell receptor deleting element transgenic reporter construct is rearranged in alpha beta but not gamma delta T-cell lineages.

    PubMed Central

    Shutter, J; Cain, J A; Ledbetter, S; Rogers, M D; Hockett, R D

    1995-01-01

    T cells can be divided into two groups on the basis of the expression of either alpha beta or gamma delta T-cell receptors (TCRs). Because the TCR delta chain locus lies within the larger TCR alpha chain locus, control of the utilization of these two receptors is important in T-cell development, specifically for determination of T-cell type: rearrangement of the alpha locus results in deletion of the delta coding segments and commitment to the alpha beta lineage. In the developing thymus, a relative site-specific recombination occurs by which the TCR delta chain gene segments are deleted. This deletion removes all D delta, J delta, and C delta genes and occurs on both alleles. This delta deletional mechanism is evolutionarily conserved between mice and humans. Transgenic mice which contain the human delta deleting elements and as much internal TCR delta chain coding sequence as possible without allowing the formation of a complete delta chain gene were developed. Several transgenic lines showing recombinations between deleting elements within the transgene were developed. These lines demonstrate that utilization of the delta deleting elements occurs in alpha beta T cells of the spleen and thymus. These recombinations are rare in the gamma delta population, indicating that the machinery for utilization of delta deleting elements is functional in alpha beta T cells but absent in gamma delta T cells. Furthermore, a discrete population of early thymocytes containing delta deleting element recombinations but not V alpha-to-J alpha rearrangements has been identified. These data are consistent with a model in which delta deletion contributes to the implementation of a signal by which the TCR alpha chain locus is rearranged and expressed and thus becomes an alpha beta T cell. PMID:8524269

  14. What controls {delta}{sup 13}C(CH{sub 4}) and {delta}D(CH{sub 4}) of peat gases?

    SciTech Connect

    Waldron, S.; Fallick, A.E.; Hall, A.J.

    1996-10-01

    {delta}{sup 13}C(CH{sub 4}), {delta}{sup 13}C(CO{sub 2}) and {delta}D(CH{sub 4}) of bacteriogenic CH{sub 4} and CO{sub 2} from Ellergower Moss, a raised peat bog in S.W. Scotland were measured from gas samples collected in situ, from two profiles, at 1 m intervals, from the surface to a depth of 5 m. {delta}{sup 13}C(CH{sub 4}) had a mean of -76{plus_minus}3{per_thousand}, {delta}{sup 13}C(CO{sub 2}) had a mean of 3.8{plus_minus}5.3{per_thousand}, {delta}D(CH{sub 4}) had a mean of -294{plus_minus}39{per_thousand}. In each profile {delta}{sup 13}C(CH{sub 4}), {delta}{sup 13}C(CO{sub 2}) arid {delta}D(CH{sub 4}) showed a general gradation from isotopically heavy at 5 m depth to isotopically light at the surface. {delta}D(CH{sub 4}) suggested the presence of a boundary between 2-3 m as the measured values from 3-5 m were 52{plus_minus}18{per_thousand} heavier than samples from 0-2 m. Such a difference was also observed with {delta}{sup 13}C(CH{sub 4}) and {delta}{sup 13}C(CO{sub 2}) measurements. One possibility is that the observed differences in isotopic profiles within the bog were substrate controlled. However {delta}{sup 13}C and {delta}D measurements of peat and porewater reveal this to be unlikely. Rather {delta}{sup 13}C(CH{sub 4}), {delta}{sup 13}C(CO{sub 2}) and {delta}D(CH{sub 4}) may be controlled by gas storage and release mechanisms within the bog.

  15. Loss of organic matter from riverine particles in deltas

    SciTech Connect

    Keil, R.G.; Quay, P.D.; Richey, J.E.

    1997-04-01

    In order to examine the transport and burial of terrigenous organic matter along the coastal zones of large river systems, we assessed organic matter dynamics in coupled river/delta systems using mineral surface area as a conservative tracer for discharged riverine particulate organic matter (POM). Most POM in the rivers studied (n = 6) is tightly associated with suspended mineral materiaL e.g., it is sorbed to mineral surfaces. Average organic loadings in the Amazon River (0.67 - 0.14 Mg C m{sup -2}), the river for which we have the largest dataset, are approximately twice that of sedimentary minerals from the Amazon Delta (-0.35 mg C m{sup -2}). Stable carbon isotope analysis indicate that approximately two-thirds of the total carbon on the deltaic particles is terrestrial. The combined surface-normalized, isotope-distinguished estimate is that >70% of the Amazon fluvial POM is not buried in the delta consistent with other independent evidence. Losses of terrestrial POM have also been quantified for the river/delta systems of Columbia in the USA, Fly in New Guinea. and Huange-He in China. If the losses of riverine POM observed in these river/delta systems are representative of rivers worldwide, then the surface-constrained analyses point toward a global loss of fluvial POM in delta regions of {approximately}0.1 x 10{sup 15} g C y{sup -1}. 28 refs., 2 figs., 1 tab.

  16. Structure of the [delta]-opioid receptor bound to naltrindole

    SciTech Connect

    Granier, Sébastien; Manglik, Aashish; Kruse, Andrew C.; Kobilka, Tong Sun; Thian, Foon Sun; Weis, William I.; Kobilka, Brian K.

    2012-07-11

    The opioid receptor family comprises three members, the {mu}-, {delta}- and {kappa}-opioid receptors, which respond to classical opioid alkaloids such as morphine and heroin as well as to endogenous peptide ligands like endorphins. They belong to the G-protein-coupled receptor (GPCR) superfamily, and are excellent therapeutic targets for pain control. The {delta}-opioid receptor ({delta}-OR) has a role in analgesia, as well as in other neurological functions that remain poorly understood. The structures of the {mu}-OR and {kappa}-OR have recently been solved. Here we report the crystal structure of the mouse {delta}-OR, bound to the subtype-selective antagonist naltrindole. Together with the structures of the {mu}-OR and {kappa}-OR, the {delta}-OR structure provides insights into conserved elements of opioid ligand recognition while also revealing structural features associated with ligand-subtype selectivity. The binding pocket of opioid receptors can be divided into two distinct regions. Whereas the lower part of this pocket is highly conserved among opioid receptors, the upper part contains divergent residues that confer subtype selectivity. This provides a structural explanation and validation for the 'message-address' model of opioid receptor pharmacology, in which distinct 'message' (efficacy) and 'address' (selectivity) determinants are contained within a single ligand. Comparison of the address region of the {delta}-OR with other GPCRs reveals that this structural organization may be a more general phenomenon, extending to other GPCR families as well.

  17. An integrated assessment framework for land subsidence in delta cities

    NASA Astrophysics Data System (ADS)

    Bucx, T. H. M.; van Ruiten, C. J. M.; Erkens, G.; de Lange, G.

    2015-11-01

    In many delta cities land subsidence exceeds absolute sea level rise up to a factor of ten by excessive groundwater extraction related to rapid urbanization and population growth. Without change, parts of Jakarta, Ho Chi Minh City, Bangkok and numerous other delta (and coastal) cities will sink below sea level. Increased flooding and also other widespread impacts of land subsidence result already in damage of billions of dollars per year. In order to gain insight in the complex, multi-sectoral aspects of subsidence, to raise awareness and to support decision making on appropriate adaptation strategies and measures, an Integrated Assessment Framework (IAF) for subsidence is introduced, illustrated by several (delta) case studies. Based on that a list of 10 generic key issues and possible solutions is presented in order to further develop and support a (generic) approach how to deal with subsidence in current and future subsidence-prone areas. For exchange of experiences and knowledge development.on subsidence in deltas the Delta Alliance, a knowledge network of deltas worldwide, can be supportive.

  18. Electronic Structure Calculations of delta-Pu Based Alloys

    SciTech Connect

    Landa, A; Soderlind, P; Ruban, A

    2003-11-13

    First-principles methods are employed to study the ground-state properties of {delta}-Pu-based alloys. The calculations show that an alloy component larger than {delta}-Pu has a stabilizing effect. Detailed calculations have been performed for the {delta}-Pu{sub 1-c}Am{sub c} system. Calculated density of Pu-Am alloys agrees well with the experimental data. The paramagnetic {yields} antiferromagnetic transition temperature (T{sub c}) of {delta}-Pu{sub 1-c}Am{sub c} alloys is calculated by a Monte-Carlo technique. By introducing Am into the system, one could lower T{sub c} from 548 K (pure Pu) to 372 K (Pu{sub 70}Am{sub 30}). We also found that, contrary to pure Pu where this transition destabilizes {delta}-phase, Pu{sub 3}Am compound remains stable in the antiferromagnetic phase that correlates with the recent discovery of a Curie-Weiss behavior of {delta}-Pu{sub 1-c}Am{sub c} at c {approx} 24 at. %.

  19. High-Pressure Behavior of Perovskite: FeTiO[subscript 3] Dissociation into (Fe[subscript 1-delta]Ti[subscript delta])O and Fe[subscript 1+delta]Ti[subscript 2-delta]O[subscript 5

    SciTech Connect

    Wu, X.; Steinle-Neumann, G.; Narygina, O.; Kantor, I.; McCammon, C.; Prakapenka, V.; Swamy, V.; Dubrovinsky, L.

    2009-09-15

    The stability of perovskite-structured materials at high pressure and temperature is of fundamental interest in solid-state physics, chemistry, and the geosciences. As an alternative to decomposition into oxides or transformation of the CaIrO{sub 3} postperovskite structure, we observe in situ the breakdown of FeTiO{sub 3} perovskite into a (Fe{sub 1-{delta}},Ti{sub {delta}})O+Fe{sub 1+{delta}}Ti{sub 2-{delta}}O{sub 5} assemblage beyond 53 GPa and 2000 K. The high-pressure high-temperature phase of Fe{sub 1+{delta}}Ti{sub 2-{delta}}O{sub 5} with a new structure (space group C2/c) could be preserved on decompression to 9 GPa, and amorphizes under further pressure release. Our study demonstrates that perovskite-structured materials can undergo chemical changes and form complex oxides with new structures, rather than only transform to denser polymorphs or decompose to simple oxides.

  20. Isotope ratio mass spectrometry: delta13C and delta15 N analysis for tracing the origin of illicit drugs.

    PubMed

    Galimov, E M; Sevastyanov, V S; Kulbachevskaya, E V; Golyavin, A A

    2005-01-01

    Gas chromatography/combustion/mass spectrometry (GC-C-MS) and elemental analysis/mass spectrometry (EA-MS) techniques are proposed to estimate delta(13)C and delta(15)N values in heroin, morphine, cocaine and hemp leaves, for the purposes of tracing the geographical origins of seized drugs. The values of isotope ratios for pure drugs and drugs with impurities were compared. It was demonstrated that large samples (up to 3 x 10(-6) g C) were combusted completely, so that the results obtained were valid. The data are considered to be an essential supplement to a wide-scale database designed specifically for the delta(13)C and delta(15)N values of drugs. The potential forensic and academic significance of the results is discussed.

  1. Chimeras of Delta6-fatty acid and Delta8-sphingolipid desaturases.

    PubMed

    Libisch, B; Michaelson, L V; Lewis, M J; Shewry, P R; Napier, J A

    2000-12-29

    The Borago officinalis Delta6 fatty acid desaturase (Boofd6) shares 58% identity in its amino acid sequence with Boofd8, a Delta8 sphingolipid desaturase from the same plant species. In order to localise the distinct catalytic properties of Boofd6 and Boofd8 to individual regions within them, a set of chimeras of these two enzymes were constructed and expressed in yeast. Chimera 2 is different from the other chimeras and Boofd6 in that it did not have any detectable desaturase activity on 18 carbon fatty acids. However, it desaturated C16 palmitoleic and C14 myristoleic acid, and the conversion rate for the later one was more than three times higher than that of Boofd6. These results suggest that the predicted membrane helices 1 and 2 of Boofd6 are involved in forming the substrate-binding site. This site appears to place constraints on the chain length of fatty acid substrates, which is similar to hydrophobic substrate binding pockets. PMID:11162428

  2. Correlation of magnetoelectric and delta-E effects in ferromagnetic-piezoelectric layered composites

    NASA Astrophysics Data System (ADS)

    Laletin, V. M.; Srinivasan, G.; Bichurin, M. I.

    2005-03-01

    Magnetoelectric (ME) coupling and its dependence on delta-E-effect have been studied in trilayers of ferromagnetic metals and lead zirconate titanate (PZT). Measurements on samples with PZT and Fe, Co, Ni or permendur (an alloy of Co-Fe-V) show evidence for strong ME interactions. Our theoretical model for bias magnetic field H dependence of ME effect predicts contributions due to two mechanisms: variation of piezomagnetic and compliance coefficients with H. The individual contributions from the two sources can be measured in the electromechanical resonance (EMR) region for the composite. Data on frequency dependence of ME coefficient reveal a giant coupling at electromechanical resonance (EMR), at 200-300 kHz for radial modes and at ˜2.7 MHz for thickness modes. Variation of compliance coefficients with H (delta-E-effect) results in a frequency shift of peak ME voltage coefficient. Theoretical profiles of ME coefficient vs. frequency agree with the data. These results are of importance for the design of signal processing devices that requires fine tuning. 1. M. I. Bichurin, D.A. Filippov, V. M. Petrov, V. M. Laletin, N. Paddubnaya, and G. Srinivasan, Phys. Rev. B 68, 132408 (2003). - supported by grants from the Russian Ministry of Education (Å02-3.4-278), the Universities of Russia Foundation (UNR 01.01.026) and the National Science Foundation (DMR-0302254).

  3. Phase modulated magnetoelectric delta-E effect sensor for sub-nano tesla magnetic fields

    NASA Astrophysics Data System (ADS)

    Zabel, S.; Kirchhof, C.; Yarar, E.; Meyners, D.; Quandt, E.; Faupel, F.

    2015-10-01

    We present a resonant micromechanical magnetic field sensor, which utilizes the magnetically induced change in elastic modulus, i.e., the delta-E effect. The sensor is based on magnetoelectric thin film composites, resulting in high sensitivity at room temperature and at low frequencies. The cantilever is electrically excited and read out by a 2 μm AlN piezoelectric layer. Depending on its magnetization, the 2 μm thin film of amorphous (Fe90Co10)78Si12B10 changes its elasticity, which results in a shift of the cantilever's resonance frequency. The sensor is operated in the first or second transversal bending mode at 7.6 kHz or 47.4 kHz. With a limit of detection of 140 pTHz-0.5 at 20 Hz under a magnetic bias field and 1 nTHz-0.5 without external bias field, this sensor exceeds all comparable designs by one order of magnitude.

  4. Harding Iceland spar: a new delta 18O-delta 13C carbonate standard for hydrothermal minerals.

    USGS Publications Warehouse

    Landis, G.P.

    1983-01-01

    An isotopically homogenous calcite, Iceland spar from the Iceberg claim, near the Harding pegmatite of N New Mexico, has delta 18O +11.78 + or - 0.07per mille (=+22.15per mille for CO2) and delta 13C -4.80 + or - 0.02per mille and has been prepared in quantities suitable for use as a working standard in MS.-R.A.H.

  5. A Conceptual Framework for Analyzing Deltas as Coupled Social-Ecological Systems: An example from the Amazon Delta

    NASA Astrophysics Data System (ADS)

    Brondizio, E.; Vogt, N. D.; Hetrick, S.; da Costa, S. M. F.; Anthony, E.

    2015-12-01

    At the nexus of watersheds, land, coastal areas, oceans, and human settlements, river delta regions pose specific challenges to environmental governance and sustainability. Using the Amazon Delta (AD) as our focus we reflect on the challenges created by the high degree of functional interdependencies shaping social-ecological dynamics of delta regions. The article introduces the initial design of an integrated conceptual framework to analyze delta regions as coupled social-ecological systems (SES). The first component of the framework is used to provide integrated definitions of delta regions according to a problem and/or collective action dilemma. Five different systematic components are suggested: social-economic systems, governance systems, ecosystems-resource systems, topographic-hydrological systems, and oceanic-climate systems. The second component of the framework presents a strategy for nested social ecological analysis to examine collective action situations in delta regions from local to regional and basin levels. The article provides illustrative applications of the framework to the Amazon Delta. First, it is used to define the AD region as a coupled, multi-level SES. We further proposed a definition of what we call the core SES of the AD. We then utilize the framework to diagnose an example collective action problem related to the impacts of urban growth and pollution on small-scale fishing resources. We argue that the functional interdependencies characteristic of delta regions require new approaches to understand, diagnose, and evaluate the current and future impact of social and environmental changes and potential solutions to the sustainability dilemmas characteristic of these regions.

  6. Architecture of a Coarse-Grained Upper Middle Cambrian Alluvial Delta Dominated by Braidplain and Gilbert-Style Delta Components

    NASA Astrophysics Data System (ADS)

    Pound, K. S.

    2014-12-01

    The ~500-m thick upper Middle Cambrian Lockett Conglomerate was deposited as part of an alluvial delta that includes Gilbert-type mega-crossbeds as well as braidplain conglomerates, and was constructed across an accretionary prism. Internal Lockett Conglomerate architecture indicates at least three phases of progradation are recorded by Gilbert-type, delta-front deposits that are separated by delta-top distributaries and/or braidplain deposits, all of which form discontinuous sheets and lenses, and record aggradation. Evaluation of sedimentary features (particle size and organization, bedding features) allows identification of eight facies within the Lockett Conglomerate; sedimentary features were used to infer transportational and depositional mechanisms. Conglomerate facies HL-1 - HL-8 were assigned to one or more of the following depositional associations: Beachface/shoreface, Deltafront, Alluvial fan, Braidplain (fluvial, unchannelized), Delta-top distributaries, and Mouth-bars. A series of Depositional Packages was identified, and mapped; integration with measured sections allowed development of a facies model for an alluvial delta in which the subaerial component is dominated by the braidplain association, and the subaqueous component by the (Gilbert-type) deltafront association as well as the delta-top distributary and mouthbar associations. Locally, the beachface association marks the transition between the subaqueous and subaerial components of the alluvial delta. Alluvial fan deposits are absent, but the rounded pebbles, cobbles and boulders with a new and distinctive provenance signature indicate derivation from a newly exposed igneous and metamorphic basement, and abrasion during transport through the fluvial (braidplain) system prior to deposition as part of the alluvial delta.

  7. Assessment of Factors Contributing to Health Outcomes in the Eight States of the Mississippi Delta Region

    PubMed Central

    Jovaag, Amanda; Catlin, Bridget B.; Rodock, Matthew; Park, Hyojun

    2016-01-01

    Introduction The objective of this observational study was to examine the key contributors to health outcomes and to better understand the health disparities between Delta and non-Delta counties in 8 states in the Mississippi River Delta Region. We hypothesized that a unique set of contributors to health outcomes in the Delta counties could explain the disparities between Delta and non-Delta counties. Methods Data were from the 2014 County Health Rankings for counties in 8 states (Alabama, Arkansas, Illinois, Kentucky, Louisiana, Mississippi, Missouri, and Tennessee). We used the Delta Regional Authority definition to identify the 252 Delta counties and 468 non-Delta counties or county equivalents. Information on health factors (eg, health behaviors, clinical care) and outcomes (eg, mortality) were derived from 38 measures from the 2014 County Health Rankings. The contributions of health factors to health outcomes in Delta and non-Delta counties were examined using path analysis. Results We found similarities between Delta counties and non-Delta counties in the health factors (eg, tobacco use, diet and exercise) that significantly predicted the health outcomes of self-rated health and low birthweight. The most variation was seen in predictors of mortality; however, Delta counties shared 2 of the 3 significant predictors (ie, community safety and income) of mortality with non-Delta counties. On average across all measures, values in the Delta were 16% worse than in the non-Delta and 22% worse than in the rest of the United States. Conclusion The health status of Delta counties is poorer than that of non-Delta counties because the health factors that contribute to health outcomes in the entire region are worse in the Delta counties, not because of a unique set of health predictors. PMID:26940300

  8. Recombinative events of the T cell antigen receptor delta gene in peripheral T cell lymphomas.

    PubMed Central

    Kanavaros, P; Farcet, J P; Gaulard, P; Haioun, C; Divine, M; Le Couedic, J P; Lefranc, M P; Reyes, F

    1991-01-01

    Recombinative events of the T cell antigen receptor (TCR) delta-chain gene were studied in 37 cases of peripheral T cell lymphoma (PTCL) and related to their clinical presentation and the expression of the alpha beta or gamma delta heterodimers as determined by immunostaining of frozen tissue samples. There were 22 cases of alpha beta, 5 cases of gamma delta, and 10 cases of silent TCR expressing neither the alpha beta nor gamma delta TCR. 5 different probes were used to examine the delta locus. The 22 cases of alpha beta PTCL displayed biallelic and monoallelic deletions; a monoallelic V delta 1 J delta 1 rearrangement was observed in 1 case and a monoallelic germ line configuration in 7 cases. The 5 cases of gamma delta PTCL displayed biallelic rearrangements: the productive rearrangements could be ascribed to V delta 1J delta 1 joining in 3 cases and VJ delta 1 joining in 2 cases according to the combined pattern of DNA hybridization with the appropriate probes and of cell reactivity with the TCR delta-1, delta TCS-1, and anti-V delta 2 monoclonal antibodies. In the VJ delta 1 joining, the rearranged V segments were located between V delta 1 and V delta 2. Interestingly, in the third group of 10 cases of silent PTCL, 5 cases were found to have a TCR gene configuration identical to that in the TCR alpha beta PTCL, as demonstrated by biallelic delta gene deletion. These 5 cases were CD3 positive. The 5 remaining cases showed a monoallelic delta gene rearrangement with a monoallelic germ line configuration in 4 and a monoallelic deletion in 1. Four of these cases were CD3 negative, which was consistent with an immature genotype the TCR commitent of which could not be ascertained. Finally, TCR gamma delta PTCL consisted of a distinct clinical morphological and molecular entity whereas TCR alpha beta and silent PTCL had a similar presentation. Images PMID:1991851

  9. Rearrangement by inversion of a T-cell receptor delta variable region gene located 3' of the delta constant region gene.

    PubMed Central

    Korman, A J; Maruyama, J; Raulet, D H

    1989-01-01

    We have located a T-cell receptor variable (V) delta gene segment immediately 3' of the delta constant (C) region gene and 5' to the known joining (J) alpha gene segments. This V delta gene is in the opposite transcriptional polarity to C delta and has rearranged to C delta by inversion in a gamma/delta-expressing hybridoma, DN7.3. This V delta gene is commonly rearranged in adult but not fetal gamma/delta-expressing thymocytes and has not been observed among alpha gene rearrangements reported to date. The reciprocal joining sequence isolated from this cell line contains N region nucleotides between the recombination signal sequences, in contrast to previously analyzed reciprocal joints. The results are discussed in the context of models accounting for ordered V gene usage during lymphocyte development. Images PMID:2789518

  10. Quantifying the signature of sediment composition on the topologic and dynamic complexity of river delta channel networks and inferences toward delta classification

    NASA Astrophysics Data System (ADS)

    Tejedor, Alejandro; Longjas, Anthony; Caldwell, Rebecca; Edmonds, Douglas A.; Zaliapin, Ilya; Foufoula-Georgiou, Efi

    2016-04-01

    Deltas contain complex self-organizing channel networks that nourish the surface with sediment and nutrients. Developing a quantitative understanding of how controlling physical mechanisms of delta formation relate to the channel networks they imprint on the landscape remains an open problem, hindering further progress on quantitative delta classification and understanding process from form. Here we isolate the effect of sediment composition on network structure by analyzing Delft3D river-dominated deltas within the recently introduced graph-theoretic framework for quantifying complexity of delta channel networks. We demonstrate that deltas with coarser incoming sediment tend to be more complex topologically (increased number of pathways) but simpler dynamically (reduced flux exchange between subnetworks) and that once a morphodynamic steady state is reached, complexity also achieves a steady state. By positioning simulated deltas on the so-called TopoDynamic complexity space and comparing with field deltas, we propose a quantitative framework for exploring complexity toward systematic inference and classification.

  11. A CAFE Delta Building Model With Channel Networks

    NASA Astrophysics Data System (ADS)

    Liang, M.; Voller, V. R.; Paola, C.; Edmonds, D.

    2009-12-01

    Mass balance sediment transport models based on the Exner equation are excellent at predicting the overall growth of river deltas, such as the position of the shoreline or the total area of delta as a function of time. The detailed evolution of delta growth, however, is dependent on the structure of the channel network which distributes the sediments. For example, vegetation dynamics along channel edges plays an important role in land building process. Therefore, to fully resolve the key delta growth processes, models must be able to evolve and track the channels on its surface. Current attempts to resolve channel networks in delta building models cover a wide range of scales. At small scales, solvers that resolve the three-dimensional flow field successfully simulate the formation of river mouth bar and channel bifurcation, but due to their computational demand they cannot be used to model a whole delta. At large scales, two-dimensional cellular models can crudely incorporate self-channelization but do not resolve the full channel network. In the middle, the coupling of Cellular Automata rules for channel evolution with Finite Element models of sediment transport (CAFE models) shows promise of providing physically and computationally feasible models. Here we borrow recent ideas from diffusion models of dendritic crystal structures, to develop a CAFE delta building model. We use an unstructured mesh of Delaunay triangulation with vertex nodes and two sets of rules are introduced as “building” and “aging” rules. Building rules describe the diffusional flux between adjacent nodes, essentially equivalent to a discrete solution of the PDE system describing diffusion of sediment in a fluvial delta. Channels are developed by selecting nodes in which sediment flux exceeds a given threshold. Interestingly bifurcations emerge at the shoreline, even though no rules specify their creation. Aging rules are applied to the cellular structure of channel networks to

  12. Anadromous salmonids in the Delta: New science 2006–2016

    USGS Publications Warehouse

    Perry, Russell W.; Buchanan, Rebecca A.; Brandes, Patricia L.; Burau, Jon R.; Israel, Joshua A

    2016-01-01

    As juvenile salmon enter the Sacramento–SanJoaquin River Delta (“the Delta”) they disperse among its complex channel network where they are subject to channel-specific processes that affect their rate of migration, vulnerability to predation, feeding success, growth rates, and ultimately, survival. In the decades before 2006, tools available to quantify growth, dispersal, and survival of juvenile salmon in this complex channel network were limited.Fortunately, thanks to technological advances such as acoustic telemetry and chemical and structural otolith analysis, much has been learned over the past decade about the role of the Delta in the life cycle of juvenile salmon. Here, we review new science between 2006and 2016 that sheds light on how different life stages and runs of juvenile salmon grow, move, and survive in the complex channel network of the Delta. One of the most important advances during the past decade has been the widespread adoption of acoustic telemetry techniques. Use of telemetry has shed light on how survival varies among alternative migration routes and the proportion of fish that use each migration route. Chemical and structural analysis of otoliths has provided insights about when juveniles left their natal river and provided evidence of extended rearing in the brackish or saltwater regions of the Delta. New advancements in genetics now allow individuals captured by trawls to be assigned to specific runs. Detailed information about movement and survival in the Delta has spurred development of agent-based models of juvenile salmon that are coupled to hydrodynamic models. Although much has been learned, knowledge gaps remain about how very small juvenile salmon (fry and parr) use the Delta. Understanding how all life stages of juvenile salmon grow, rear, and survive in the Delta is critical for devising management strategies that support a diversity of life history strategies.

  13. Structural Insights into Clostridium perfringens Delta Toxin Pore Formation

    PubMed Central

    Huyet, Jessica; Naylor, Claire E.; Savva, Christos G.; Gibert, Maryse; Popoff, Michel R.; Basak, Ajit K.

    2013-01-01

    Clostridium perfringens Delta toxin is one of the three hemolysin-like proteins produced by C. perfringens type C and possibly type B strains. One of the others, NetB, has been shown to be the major cause of Avian Nectrotic Enteritis, which following the reduction in use of antibiotics as growth promoters, has become an emerging disease of industrial poultry. Delta toxin itself is cytotoxic to the wide range of human and animal macrophages and platelets that present GM2 ganglioside on their membranes. It has sequence similarity with Staphylococcus aureus β-pore forming toxins and is expected to heptamerize and form pores in the lipid bilayer of host cell membranes. Nevertheless, its exact mode of action remains undetermined. Here we report the 2.4 Å crystal structure of monomeric Delta toxin. The superposition of this structure with the structure of the phospholipid-bound F component of S. aureus leucocidin (LukF) revealed that the glycerol molecules bound to Delta toxin and the phospholipids in LukF are accommodated in the same hydrophobic clefts, corresponding to where the toxin is expected to latch onto the membrane, though the binding sites show significant differences. From structure-based sequence alignment with the known structure of staphylococcal α-hemolysin, a model of the Delta toxin pore form has been built. Using electron microscopy, we have validated our model and characterized the Delta toxin pore on liposomes. These results highlight both similarities and differences in the mechanism of Delta toxin (and by extension NetB) cytotoxicity from that of the staphylococcal pore-forming toxins. PMID:23805259

  14. Surface Process Control on Stratigraphic Completeness in Simple Experimental Deltas

    NASA Astrophysics Data System (ADS)

    Hobley, D. E. J.; Tucker, G. E.; Mahon, R. C.; Barnhart, K. R.; Shaw, J.; Liang, M.; Paola, C.; Voller, V. R.

    2015-12-01

    The ability to measure and understand stratigraphic completeness is fundamental to the interpretation of the sedimentary record. It provides the epistemic basis that allows us to predict the preservation potential of input signals to sedimentary systems, and gives us a null hypothesis of sorts against which real stratigraphic sequences can be compared. Stratigraphic completeness essentially sets the resolution of a seismic section. However, despite the importance of stratigraphic completeness, significant gaps remain in our understanding, especially as regards the mechanistic underpinnings of how real geomorphic and transport processes influence completeness. Here we use a suite of reduced complexity numerical models of a delta to investigate what degree of realism in representation of surface processes is required to match measured completeness-timescale relationships in real systems. Target data is drawn from experimental deltas, where input variables are known and well constrained. We explore the extent to which surface processes - in particular, expressed as the spatial restriction of and correlation between loci of erosion and deposition on the delta top and front - control completeness, independent of the forcing parameters of sediment input and base level. We illustrate the importance of data resolution in controlling measured completeness, and demonstrate that these resolution effects can combine with trends driven by process localization on the delta top. We discuss the extent to which these two effects can or cannot be distinguished in real data. We argue that signals of localized erosion on the delta top and localized deposition on the delta front are key drivers of completeness-timescale trends, even for simple Gilbert-style deltas under elementary experimental boundary conditions.

  15. Documenting Erosion of the St. Bernard Delta: Past and Present

    NASA Astrophysics Data System (ADS)

    Pendleton, E. A.; Twichell, D. C.; Baldwin, W. E.

    2008-12-01

    The Chandeleur Islands lie off the coast of eastern Louisiana and are thought to have formed as a barrier- island arc at the maximum extent of the St. Bernard Delta Complex of the Mississippi River between 2500 and 3000 yr BP. The relatively planar, deltaic stratigraphy of this region represents a unique opportunity to approximate the volume of sediment removed since formation and identify erosional processes driving the ongoing evolution of the delta complex. Detailed mapping of the stratigraphic facies of this delta complex, which indicates the presence of distributary sands, interdistributary muds, delta-front sandy muds, prodelta clays, and barrier-island sands, was interpreted from a dense network of geophysical (seismic-reflection, sidescan-sonar, and swath-bathymetry) and vibracore data collected offshore of the Chandeleur Islands in 2006 and 2007. Truncation of deltaic units on the modern shoreface and inner continental shelf indicates that the delta-front has been eroded significantly since the islands began retreating landward. At a finer scale, subcircular and linear depressions on the modern shoreface may be indicative of recent, event-driven erosion. The subcircular features occur in delta-front deposits, range from 7 to greater than 300 meters in diameter, and are commonly associated with gas-escape structures on seismic profiles. The linear features have lengths greater than 500 m, widths less than 300 m, and occur where distributary-channel deposits crop out on the seafloor. These features suggest that different delta facies respond uniquely to landward retreat of the shoreface and oceanographic processes acting on the ravinement surface. Although, the extent of geomorphologic control imposed on the modern barrier system by the location of distributary channels in the coastal zone is not well defined, the barrier islands, in part owe their continued existence to the reworking of sand from the continental shelf by erosional processes and subsequent

  16. Domain exchange experiments in duck delta-crystallins: functional and evolutionary implications.

    PubMed Central

    Sampaleanu, L. M.; Davidson, A. R.; Graham, C.; Wistow, G. J.; Howell, P. L.

    1999-01-01

    Delta-crystallin, the major soluble protein component of the avian and reptilian eye lens, is homologous to the urea cycle enzyme argininosuccinate lyase (ASL). In duck lenses there are two delta crystallins, denoted delta1 and delta2. Duck delta2 is both a major structural protein of the lens and also the duck orthologue of ASL, an example of gene recruitment. Although 94% identical to delta2/ASL in the amino acid sequence, delta1 is enzymatically inactive. A series of hybrid proteins have been constructed to assess the role of each structural domain in the enzymatic mechanism. Five chimeras--221, 122, 121, 211, and 112, where the three numbers correspond to the three structural domains and the value of 1 or 2 represents the protein of origin, delta1 or delta2, respectively--were constructed and thermodynamically and kinetically analyzed. The kinetic analysis indicates that only domain 1 is crucial for restoring ASL activity to delta1 crystallin, and that amino acid substitutions in domain 2 may play a role in substrate binding. These results confirm the hypothesis that only one domain, domain 1, is responsible for the loss of catalytic activity in delta1. The thermodynamic characterization of human ASL (hASL) and duck delta1 and delta2 indicate that delta crystallins are slightly less stable than hASL, with the delta1 being the least stable. The deltaGs of unfolding are 57.25, 63.13, and 70.71 kcal mol(-1) for delta1, delta2, and hASL, respectively. This result was unexpected, and we speculate that delta crystallins have adapted to their structural role by adopting a slightly less stable conformation that might allow for enhanced protein-protein and protein-solvent interactions. PMID:10091655

  17. Remote Sensing Study of The Volga Delta Flooding Dynamics

    NASA Astrophysics Data System (ADS)

    Tsitsenko, K. V.; Shalygin, A. L.

    The Volga Delta is the lowest part of the Volga basin where the river divides to hun- dreds of branches of different scales, forming a great amount of islands and permanent or temporary lakes. Considerable part of these islands can be covered temporarily by the river water during the spring-flood, or for a long time by the Caspian Sea water during the high Sea level stages. The main part of the Volga runoff losses (in average about 10 km3/year) takes place in the Delta. These losses depend on the proportion of land and water areas, depending in its turn on the Caspian Sea level and on the Volga river flow phase. The rice irrigation, which requires great amounts of water, causes considerable anthropogenic runoff losses in the Delta. Remote sensing study of the Volga Delta was carried out to define the following: - The Sea border of the Delta and its dynamics depending on the Sea level; - Water surface area dynamics in the Delta depending on the Volga hydrological phase and the spring flood volume; - The inter-year and long-term landuse dynamics in the Delta. 13 digital satellite images of the Delta from 1970s - 1990s were used for realization of the study: 3 Landsat-MSS (USA, 4 spectral bands), 4 Landsat-TM (USA, 7 bands) and 6 Resource-01 (Russia, 2-4 bands), chosen on a principle of scope both all amplitude of the Sea level and various phases of the Volga hydrological regime. Classification of the images was car- ried out by means of the GIS-system ILWIS, using both original spectral bands and calculated artificial bands, such as NDVI, SWCI, LWCI, etc. From 4 to 5 bands with the least correlation were used for classification of each image. Analysis of classifica- tion results has shown that water surface in the Delta during low-flow period occupied 5-7% of the area, sharply growing (to 50%) during the spring high water. The area of half-submerged reeds, located along the Sea coast, reduced from 34% in 1970s to 20- 24% in 1980s, and by 1995 the significant part of

  18. Numerical studies of incompressible flow around delta and double-delta wings

    NASA Technical Reports Server (NTRS)

    Krause, E.; Liu, C. H.

    1989-01-01

    The subject has been jointly investigated at NASA Langley Research Center and the Aerodynamisches Institut of the RWTH Aachen over a substantial period. The aim of this investigation has been to develop numerical integration procedures for the Navier-Stokes equations - particularly for incompressible three-dimensional viscous flows about simple and double delta wings - and to study the low speed flow behavior, with its complex vortex structures on the leeward side of the wing. The low speed flight regime poses unusual problems because high incidence flight conditions may, for example, encounter symmetric and asymmetric vortex breakdown. Because of the many difficulties to be expected in solving the problem, it was divided into two - analysis of the flow without vortex breakdown and analysis of the breakdown of isolated vortices. The major results obtained so far on the two topics are briefly described.

  19. Preparing the Dutch delta for future droughts: model based support in the national Delta Programme

    NASA Astrophysics Data System (ADS)

    ter Maat, Judith; Haasnoot, Marjolijn; van der Vat, Marnix; Hunink, Joachim; Prinsen, Geert; Visser, Martijn

    2014-05-01

    Keywords: uncertainty, policymaking, adaptive policies, fresh water management, droughts, Netherlands, Dutch Deltaprogramme, physically-based complex model, theory-motivated meta-model To prepare the Dutch Delta for future droughts and water scarcity, a nation-wide 4-year project, called Delta Programme, is established to assess impacts of climate scenarios and socio-economic developments and to explore policy options. The results should contribute to a national adaptive plan that is able to adapt to future uncertain conditions, if necessary. For this purpose, we followed a model-based step-wise approach, wherein both physically-based complex models and theory-motivated meta-models were used. First step (2010-2011) was to make a quantitative problem description. This involved a sensitivity analysis of the water system for drought situations under current and future conditions. The comprehensive Dutch national hydrological instrument was used for this purpose and further developed. Secondly (2011-2012) our main focus was on making an inventory of potential actions together with stakeholders. We assessed efficacy, sell-by date of actions, and reassessed vulnerabilities and opportunities for the future water supply system if actions were (not) taken. A rapid assessment meta-model was made based on the complex model. The effects of all potential measures were included in the tool. Thirdly (2012-2013), with support of the rapid assessment model, we assessed the efficacy of policy actions over time for an ensemble of possible futures including sea level rise and climate and land use change. Last step (2013-2014) involves the selection of preferred actions from a set of promising actions that meet the defined objectives. These actions are all modeled and evaluated using the complex model. The outcome of the process will be an adaptive management plan. The adaptive plan describes a set of preferred policy pathways - sequences of policy actions - to achieve targets under

  20. DeltaA/DeltaD regulate multiple and temporally distinct phases of notch signaling during dopaminergic neurogenesis in zebrafish.

    PubMed

    Mahler, Julia; Filippi, Alida; Driever, Wolfgang

    2010-12-01

    Dopaminergic neurons develop at distinct anatomical sites to form some of the major neuromodulatory systems in the vertebrate brain. Despite their relevance in neurodegenerative diseases and the interests in reconstitutive therapies from stem cells, mechanisms of the neurogenic switch from precursor populations to dopaminergic neurons are not well understood. Here, we investigated neurogenesis of different dopaminergic and noradrenergic neuron populations in the zebrafish embryo. Birth-dating analysis by EdU (5-ethynyl-2'-deoxyuridine) incorporation revealed temporal dynamics of catecholaminergic neurogenesis. Analysis of Notch signaling mutants and stage-specific pharmacological inhibition of Notch processing revealed that dopaminergic neurons form by temporally distinct mechanisms: dopaminergic neurons of the posterior tuberculum derive directly from neural plate cells during primary neurogenesis, whereas other dopaminergic groups form in continuous or wavelike neurogenesis phases from proliferating precursor pools. Systematic analysis of Notch ligands revealed that the two zebrafish co-orthologs of mammalian Delta1, DeltaA and DeltaD, control the neurogenic switch of all early developing dopaminergic neurons in a partially redundant manner. DeltaA/D may also be involved in maintenance of dopaminergic precursor pools, as olig2 expression in ventral diencephalic dopaminergic precursors is affected in dla/dld mutants. DeltaA/D act upstream of sim1a and otpa during dopaminergic specification. However, despite the fact that both dopaminergic and corticotropin-releasing hormone neurons derive from sim1a- and otpa-expressing precursors, DeltaA/D does not act as a lineage switch between these two neuronal types. Rather, DeltaA/D limits the size of the sim1a- and otpa-expressing precursor pool from which dopaminergic neurons differentiate. PMID:21148001

  1. Hepatitis delta virus: protein composition of delta antigen and its hepatitis B virus-derived envelope.

    PubMed Central

    Bonino, F; Heermann, K H; Rizzetto, M; Gerlich, W H

    1986-01-01

    Hepatitis delta virus (HDV)-associated particles were purified from the serum of an experimentally infected chimpanzee by size chromatography and by density centrifugation. Hepatitis delta antigen (HDAg) was detected after mild detergent treatment at a column elution volume corresponding to 36-nm particles and banded at a density of 1.25 g/ml. The serum had an estimated titer of 10(9) to 10(10) HDV-associated particles and had only a 10-fold excess of hepatitis B surface antigen (HBsAg) not associated with HDAg. Therefore, HDV appears to be much more efficiently packed and secreted than is its helper virus, hepatitis B virus (HBV), which is usually accompanied by a 1,000-fold excess of HBsAg. The protein compositions of the HDAg-containing particles were analyzed by immunoblotting with HDAg-, HBsAg-, and hepatitis B core antigen-specific antisera and monoclonal antibodies to HBV surface gene products. The HBsAg envelope of HDAg contained approximately 95% P24/GP27s, 5% GP33/36s, and 1% P39/GP42s proteins. This protein composition was more similar to that of the 22-nm particles of HBsAg than to that of complete HBV. The significant amount of GP33/36s suggests that the HBsAg component of the HDV-associated particle carries the albumin receptor. Two proteins of 27 and 29 kilodaltons which specifically bound antibody to HDAg but not HBV-specific antibodies were detected in the interior of the 36-nm particle. Since these proteins were structural components of HDAg and were most likely coded for by HDV, they were designated P27d and P29d. Images PMID:3701932

  2. Hepatitis delta virus in intravenous drug users in Kuala Lumpur.

    PubMed

    Duraisamy, G; Zuridah, H; Ariffin, Y; Kek, C S

    1994-09-01

    The hepatitis delta virus (HDV) is an RNA containing virus that requires hepatitis B virus (HBV) to supply the envelope proteins. HDV only infect man in the presence of HBV, either as a coinfection or as superinfection in HBV carriers. In the presence of hepatitis B infection, the HDV may cause more severe liver damage than that caused by the hepatitis B virus alone. HDV infection was studied in 44 HBsAg positive serum samples collected from male intravenous drug users sent for screening to the Blood Services Centre (BSC), Hospital Kuala Lumpur (HKL) between 1990 and 1992. The majority (39) were in the 20 to 39 age group. The youngest was 19 years old and the oldest was 61 years old. There were 25 Malays, 13 Chinese, five Indians and one Albanian. Anti hepatitis delta antibody (Anti-HDV) was detected in 15 out of 44 (34%) of the drug addicts. These results shows an increased in delta infection in HBsAg positive intravenous drug addicts compared to the surveillance results in 1985 when no delta antibodies were detected, and the 1986 and 1989 surveillance which showed 17.8% and 20% delta antibody positivity respectively.

  3. Martian stepped-delta formation by rapid water release.

    PubMed

    Kraal, Erin R; van Dijk, Maurits; Postma, George; Kleinhans, Maarten G

    2008-02-21

    Deltas and alluvial fans preserved on the surface of Mars provide an important record of surface water flow. Understanding how surface water flow could have produced the observed morphology is fundamental to understanding the history of water on Mars. To date, morphological studies have provided only minimum time estimates for the longevity of martian hydrologic events, which range from decades to millions of years. Here we use sand flume studies to show that the distinct morphology of martian stepped (terraced) deltas could only have originated from a single basin-filling event on a timescale of tens of years. Stepped deltas therefore provide a minimum and maximum constraint on the duration and magnitude of some surface flows on Mars. We estimate that the amount of water required to fill the basin and deposit the delta is comparable to the amount of water discharged by large terrestrial rivers, such as the Mississippi. The massive discharge, short timescale, and the associated short canyon lengths favour the hypothesis that stepped fans are terraced delta deposits draped over an alluvial fan and formed by water released suddenly from subsurface storage. PMID:18288190

  4. Martian stepped-delta formation by rapid water release.

    PubMed

    Kraal, Erin R; van Dijk, Maurits; Postma, George; Kleinhans, Maarten G

    2008-02-21

    Deltas and alluvial fans preserved on the surface of Mars provide an important record of surface water flow. Understanding how surface water flow could have produced the observed morphology is fundamental to understanding the history of water on Mars. To date, morphological studies have provided only minimum time estimates for the longevity of martian hydrologic events, which range from decades to millions of years. Here we use sand flume studies to show that the distinct morphology of martian stepped (terraced) deltas could only have originated from a single basin-filling event on a timescale of tens of years. Stepped deltas therefore provide a minimum and maximum constraint on the duration and magnitude of some surface flows on Mars. We estimate that the amount of water required to fill the basin and deposit the delta is comparable to the amount of water discharged by large terrestrial rivers, such as the Mississippi. The massive discharge, short timescale, and the associated short canyon lengths favour the hypothesis that stepped fans are terraced delta deposits draped over an alluvial fan and formed by water released suddenly from subsurface storage.

  5. Delta hepatitis: molecular biology and clinical and epidemiological features.

    PubMed Central

    Polish, L B; Gallagher, M; Fields, H A; Hadler, S C

    1993-01-01

    Hepatitis delta virus, discovered in 1977, requires the help of hepatitis B virus to replicate in hepatocytes and is an important cause of acute, fulminant, and chronic liver disease in many regions of the world. Because of the helper function of hepatitis delta virus, infection with it occurs either as a coinfection with hepatitis B or as a superinfection of a carrier of hepatitis B surface antigen. Although the mechanisms of transmission are similar to those of hepatitis B virus, the patterns of transmission of delta virus vary widely around the world. In regions of the world in which hepatitis delta virus infection is not endemic, the disease is confined to groups at high risk of acquiring hepatitis B infection and high-risk hepatitis B carriers. Because of the propensity of this viral infection to cause fulminant as well as chronic liver disease, continued incursion of hepatitis delta virus into areas of the world where persistent hepatitis B infection is endemic will have serious implications. Prevention depends on the widespread use of hepatitis B vaccine. This review focuses on the molecular biology and the clinical and epidemiologic features of this important viral infection. PMID:8358704

  6. STATISTICAL PROPERTIES OF GALACTIC {delta} SCUTI STARS: REVISITED

    SciTech Connect

    Chang, S.-W.; Kim, D.-W.; Byun, Y.-I.; Protopapas, P. E-mail: kim@mpia-hd.mpg.de

    2013-05-15

    We present statistical characteristics of 1578 {delta} Scuti stars including nearby field stars and cluster member stars within the Milky Way. We obtained 46% of these stars (718 stars) from work by Rodriguez and collected the remaining 54% of stars (860 stars) from other literature. We updated the entries with the latest information of sky coordinates, color, rotational velocity, spectral type, period, amplitude, and binarity. The majority of our sample is well characterized in terms of typical period range (0.02-0.25 days), pulsation amplitudes (<0.5 mag), and spectral types (A-F type). Given this list of {delta} Scuti stars, we examined relations between their physical properties (i.e., periods, amplitudes, spectral types, and rotational velocities) for field stars and cluster members, and confirmed that the correlations of properties are not significantly different from those reported in Rodriguez's work. All the {delta} Scuti stars are cross-matched with several X-ray and UV catalogs, resulting in 27 X-ray and 41 UV-only counterparts. These counterparts are interesting targets for further study because of their uniqueness in showing {delta} Scuti-type variability and X-ray/UV emission at the same time. The compiled catalog can be accessed through the Web interface http://stardb.yonsei.ac.kr/DeltaScuti.

  7. ThemeDelta: Dynamic Segmentations over Temporal Topic Models.

    PubMed

    Gad, Samah; Javed, Waqas; Ghani, Sohaib; Elmqvist, Niklas; Ewing, Tom; Hampton, Keith N; Ramakrishnan, Naren

    2015-05-01

    We present ThemeDelta, a visual analytics system for extracting and visualizing temporal trends, clustering, and reorganization in time-indexed textual datasets. ThemeDelta is supported by a dynamic temporal segmentation algorithm that integrates with topic modeling algorithms to identify change points where significant shifts in topics occur. This algorithm detects not only the clustering and associations of keywords in a time period, but also their convergence into topics (groups of keywords) that may later diverge into new groups. The visual representation of ThemeDelta uses sinuous, variable-width lines to show this evolution on a timeline, utilizing color for categories, and line width for keyword strength. We demonstrate how interaction with ThemeDelta helps capture the rise and fall of topics by analyzing archives of historical newspapers, of U.S. presidential campaign speeches, and of social messages collected through iNeighbors, a web-based social website. ThemeDelta is evaluated using a qualitative expert user study involving three researchers from rhetoric and history using the historical newspapers corpus.

  8. On the precipitation of delta phase in ALLVAC® 718Plus

    NASA Astrophysics Data System (ADS)

    Messé, O. M.; Barnard, J. S.; Pickering, E. J.; Midgley, P. A.; Rae, C. M. F.

    2014-04-01

    ALLVAC 718Plus is a new commercial superalloy derived from Inconel 718, but possessing a higher temperature capability whilst employing the same philosophy regarding the microstructure. Many articles have been published describing various heat treatments exploiting the precipitation of intermetallic phases at grain boundaries to optimize the mechanical properties over a range of testing conditions. The requirement to further improve the mechanical properties of this alloy drives our interest in the precipitation mechanism of the delta and eta phases found in this alloy. We report the presence of finely layered structures composed of two phases, delta and eta, with distinct structures and chemistries. Possible pathways to explain this precipitation in 718Plus are considered as follows: (i) the sequential formation of the delta from eta phase and (ii) the simultaneous precipitation of both eta and delta facilitated via solute rejection. Both can result in the formation of those small delta layers observed in HRSTEM. We discuss which is most likely by comparing the relative alignment of the phases by image processing and the analysis of the HRSTEM images, and propose formation mechanisms consistent with the distinctive dislocation structures observed at the interface.

  9. Ancient Martian Deltas: Evidence for Shallow and Deep Standing Bodies of Water

    NASA Astrophysics Data System (ADS)

    Jew, C. L.; Kim, W.; Lim, Y.; Piliouras, A.

    2015-12-01

    Ancient deltas on Mars are indicative of a geologic history composed of complex fluvio-deltaic deposits. We focus on two morphologically different deltas preserved on Mars, one located in the Jezero crater and the other in the Shalbatana Valles canyon. The Jezero delta, formed during the Noachian age, is a large fluvial delta with strong channelization and a rigid shoreline resembling a terrestrial delta. In contrast, the Shalbatana Delta is a smaller scaled more briefly lived delta system, developed during the Hesperian, that is characterized by its smooth and simple planform. Evidence from previous studies on these Martian deltas such as the base level, mechanism to build sediment cohesion, estimated discharge, and time of formation offer support to ultimately discover why one delta drastically differs from the other. Based upon the observations from these two locations, we investigate through our physical experiments the conditions required to create these prograding deltas. We use carbonate precipitation in our experiments as a mechanism to increase bank stability, an alternative for any chemically driven precipitated deposits that potentially improve cohesion as vegetation does for terrestrial deltas. We found that there are differences in floodplain thickness, channelization, shoreline rugosity, and delta shape in the carbonate verse non-carbonate runs. Additionally, we conducted runs for isolating the influence that shallow and deep standing bodies of water have on prograding deltas. The experimental results suggested that the highly channelized delta (e.g., Jezero delta) rapidly prograded into a shallow body of water, covering a broader surface area and is dependent on a cohesive force for channel organization. On the contrary, Gilbert-type delta (e.g., Shalbatana delta) was best replicated when prograding into a deep standing body of water. Investigation using the experimental carbonate deltas suggests that cohesion results in better channelization (more

  10. Pen Branch stream corridor and Delta Wetlands change assessment

    SciTech Connect

    Blohm, J.D.

    1995-06-01

    Airborne multispectral scanner data from 1987 to 1991 covering the Pen Branch corridor and delta at SRS were utilized to provide a detailed change detection analysis. The multispectral data were geo-referenced to a Universal Transverse Mercator projection using finite element registration. Each year was then classified into eleven different landcover categories, and the yearly changes in each landcover category were analyzed. The decrease in operations of K Reactor in 1988 has resulted in drying of the corridor and delta. This has led to the decline of nonpersistent vegetation and the increase of persistent vegetation. Cattails, willow, and bottomland hardwoods, in particular, have grown to dominate the corridor and most of the delta.

  11. Theory for the curvature dependence of delta front progradation

    NASA Astrophysics Data System (ADS)

    Ke, Wun-Tao; Capart, Hervé

    2015-12-01

    When Gilbert-type deltas respond to uneven sediment supply or advance over irregular basin bathymetry, they develop curved, creased fronts prograding at speeds that vary with location along the shoreline. Relations governing the progradation rate, however, have so far been proposed only for simple special cases. In this paper, we exploit the special properties of solutions to the eikonal equation to derive a general progradation relation, applicable to delta fronts of finite angle of repose and arbitrary shoreline planform. In these circumstances, the theory explicitly relates the progradation rate to the local shoreline curvature. We illustrate the resulting morphodynamics with numerical and analytical solutions for a sinuous delta front. The proposed relation can be used to model deltaic evolution or deduce spanwise distributions of sediment supply rates from observations of foreset evolution.

  12. delta. sigma/sub L//(pp) and jet physics

    SciTech Connect

    Richards, D.G.

    1988-01-01

    We show that there is a positive contribution to ..delta..sigma/sub L/(pp; s) = sigma /sub tot/(p(+)p(+); s) /minus/ sigma/sub tot/(p(+)p(/minus/); s) (where the +- refer to proton helicities) associated with the pointlike scattering of fundamental constituents. Simple arguments imply that this positive contribution would, at very high s, be larger in absolute value than the negative contribution to ..delta..sigma/sub L/ predicted from the exchange of the A/sub 1/ reggeon, and furthermore may provide important insight into the shape of the spin weighted quark and gluon distributions. Measurements of ..delta..sigma/sub L/ in the energy range ..sqrt..s = 18 /minus/ 30 GeV also should help clarify theoretical ideas associated with the observations of ''minijets'' and could aid in the prediction of event structure at future high energy colliders. 24 refs. 6 figs.

  13. The Delta IV launch table begins transfer to CCAFS

    NASA Technical Reports Server (NTRS)

    2000-01-01

    A launch table, fabricated by Jered Industries in Georgia for Boeing, moves away from the turn basin and the barge that brought it to the turn basin in KSC's Launch Complex 39 Area. In the background is the Vehicle Assembly Building. The table was built in support of the Delta Evolved Expendable Launch Vehicle (EELV) program, known as Delta IV. It was floated on the barge down the Intercoastal Waterway, through the Barge Canal to the turn basin. The table is approximately 70 feet long, 40 feet wide and 50 feet high, and weighs about 600,000 pounds. It is being transferred to Launch Complex 37B, Cape Canaveral Air Force Station, the Delta IV launch site. Accompanying the launch table on the barge are flame deflectors, which are also to be erected on pad 37B.

  14. Nile delta: Recent geological evolution and human impact

    SciTech Connect

    Stanley, D.J.; Warne, A.G. )

    1993-04-30

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

  15. Ecology of delta marshes of coastal Louisiana: a community profile

    SciTech Connect

    Gosselink, J.G.

    1984-05-01

    This report reviews and synthesizes ecological information and data on the extensive marshes of the Mississippi River Deltaic Plain. Over the past 6000 years the river has built a delta onto the Continental Shelf of the Gulf of Mexico covering about 23,900 km/sup 2/. This low land is primarily marshes and represents about 22% of the total coastal wetland area of the 48 conterminous United States. The delta is notable for its high primary productivity, its valuable fishery and fur industry, and the recreational fishing and hunting it supports. The Mississippi River delta marshes are subject to the unique problem of extremely rapid marsh degradation due to a complex mixture of natural processes and human activities that include worldwide sea-level rise; subsidence; navigation and extractive industry canal dredging; flood control measures that channel the river; and pollution from domestic sewage, exotic organic chemicals, and heavy metals. 262 references, 75 figures, 34 tables.

  16. Dynamical instabilities of warm npe matter: {delta} meson effects

    SciTech Connect

    Pais, Helena; Santos, Alexandre; Providencia, Constanca

    2009-10-15

    The effects of {delta} mesons on the dynamical instabilities of cold and warm nuclear and stellar matter at subsaturation densities are studied in the framework of relativistic mean-field hadron models (NL3, NL{rho}, and NL{rho}{delta}) with the inclusion of the electromagnetic field. The distillation effect and the spinodals for all the models considered are discussed. The crust-core transition density and pressure are obtained as a function of temperature for {beta}-equilibrium matter with and without neutrino trapping. An estimation of the size of the clusters formed in the nonhomogeneous phase and the corresponding growth rates are made. It is shown that cluster sizes increase with temperature. The effects of the {delta} meson on the instability region are larger for low temperatures, very asymmetric matter, and densities close to the spinodal surface. It increases the distillation effect above {approx}0.4{rho}{sub 0} and has the opposite effect below that density.

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

    SciTech Connect

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

    1999-11-01

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

  18. The Chandra/MOST Campaign on Delta Ori A

    NASA Astrophysics Data System (ADS)

    Corcoran, Michael

    2014-11-01

    X-ray emission from massive stars is produced by shocked gas distributed throughout their unstable stellar winds. These shocks play a significant role in determining accurate stellar mass loss rates. Our current understanding of these shocks is derived from indirect indicators like line profile shapes and the f/i ratio of the He-like triplets. Here we discuss a campaign of phase-resolved Chandra grating observations and simultaneous high-precision photometry using the MOST satellite of the massive binary Delta Ori A, in an attempt to directly constrain the radial extent of the hot gas in the wind of the primary star (Delta Ori Aa) via occultation by the X-ray faint secondary (Delta Ori Ab). We present an overview of this campaign and a summary of our results.

  19. Fluvial transport on Titan: formation and evolution of river deltas

    NASA Astrophysics Data System (ADS)

    Witek, Piotr Przemyslaw; Czechowski, Leszek

    2016-10-01

    The Cassini-Huygens mission provided numerous observations indicating that processes of sediment transport are currently operating on the surface of Titan. We performed numerical simulations of flow and sediment transport on Titan with particular emphasis on formation of sedimentary landforms in Titan's lakes. We compared the morphology and evolution of landforms formed in Titanian and terrestrial conditions, under various discharges and with different dominant grain sizes. The processes are similar in both environments; in some cases we observed bifurcation of the flow and switching of the active distributaries. Such processes may lead to abandonment of some delta lobes, as hypothesized for the delta observed in Ontario Lacus on Titan. The lower gravity of Titan and higher buoyancy of the most plausible kinds of sediment result in higher efficiency of transport and generally faster evolution of the deltaic deposits. Our results suggest also that the flat, lobate river deltas may form in narrower range of parameters than on Earth.

  20. Morphology of river deltas on Titan and Earth

    NASA Astrophysics Data System (ADS)

    Witek, Piotr; Czechowski, Leszek

    2016-07-01

    The Cassini-Huygens mission is entering its final phase. The landing of Huygens on Titan and flybys performed by the Cassini probe during the last ten years revolutionized our knowledge about that moon, revealing a complex fluvio-lacustrine environment. Despite significant differences in composition, temperature and gravity, the processes of sediment transport and deposition are similar on Earth and Titan. We performed numerical simulations of development of river deltas in Titanian and terrestrial conditions, under various discharges and with different dominant grain sizes. We found that evolution of deltaic deposits is more rapid on Titan due to higher efficiency of transport, but the flat, lobate river deltas may form in narrower range of parameters than on Earth. Our results help in understanding the evolution of sedimentary deposits and may partially explain the paucity of river deltas in Titan's lakes.

  1. [Transport characteristics of air pollutants over the Yangtze Delta].

    PubMed

    Wang, Yan; Chai, Fa-He; Wang, Yong-Hong; Liu, Ming

    2008-05-01

    Meteorological field of January, April, July and October in 2004 was obtained by running MM5 with NCEP datasets. Then we used HYSPLIT 4.8 model to calculate the backward and forward trajectories of representative cities. Distributions of trajectories and the affected areas vary with seasons. Transport current affecting Yangtze River Delta is mainly from Mongolia, North China or Northeast region, via Yellow Sea area, Shandong, Jiangsu province or Shanghai. Another important transport path is current from southwest because of the Southwest monsoon. A movement of East Asia monsoon plays an important part in the mesoscale transport of pollutants in Yangtze Delta. Winter monsoon is a main mechanism which moves the air pollutants in Yangtze Delta to South China and West Pacific ocean. Another important transport system is the subtropical anticyclone over the western Pacific Ocean which controls the east coast of our country in spring and summer. This circulation system mainly affects the inland area of our country.

  2. Transgenic expression of salmon delta-5 and delta-6 desaturase in zebrafish muscle inhibits the growth of Vibrio alginolyticus and affects fish immunomodulatory activity.

    PubMed

    Wang, Yi-Da; Peng, Kuan-Chieh; Wu, Jen-Leih; Chen, Jyh-Yih

    2014-08-01

    Marine fish are an important nutritional source for highly polyunsaturated fatty acids (PUFAs). PUFA biosynthesis requires the following key enzymes: delta-4 (Δ-4) desaturase, delta-5 (Δ-5) desaturase, delta-6 (Δ-6) desaturase, delta-5 (Δ-5) elongase, and delta-6 (Δ-6) elongase. The effect of overexpressing delta-5 desaturase and/or delta-6 desaturase in zebrafish muscle has not previously been reported. Herein, we investigated the effects of these proteins on antibacterial and immunomodulatory activity in transgenic zebrafish infected with Vibrio alginolyticus. Overexpression of delta-5 and delta-6 desaturase enhanced antibacterial activity at 4 and 12 h after injection of bacteria into muscle, as compared to controls. Furthermore, expression of immune-related genes (IL-1β, IL-22, and TNF-α) was observed to be altered in transgenic fish after 4 h of bacterial infection, resulting in a significant decrease in the inflammatory response, as compared to control fish. These results demonstrate that muscle-specific expression of transgenic desaturases in zebrafish not only enhance PUFA production, but also enhance antibacterial and anti-inflammatory activity. Overall, these results identify delta-5 and delta-6 desaturase as novel candidate genes for use in aquaculture, to enhance both disease resistance and fish oil production.

  3. Mississippi Delta, Radar Image with Colored Height

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Click on the image for the animation

    About the animation: This simulated view of the potential effects of storm surge flooding on Lake Pontchartrain and the New Orleans area was generated with data from the Shuttle Radar Topography Mission. Although it is protected by levees and sea walls against storm surges of 18 to 20 feet, much of the city is below sea level, and flooding due to storm surges caused by major hurricanes is a concern. The animation shows regions that, if unprotected, would be inundated with water. The animation depicts flooding in one-meter increments.

    About the image: The geography of the New Orleans and Mississippi delta region is well shown in this radar image from the Shuttle Radar Topography Mission. In this image, bright areas show regions of high radar reflectivity, such as from urban areas, and elevations have been coded in color using height data also from the mission. Dark green colors indicate low elevations, rising through yellow and tan, to white at the highest elevations.

    New Orleans is situated along the southern shore of Lake Pontchartrain, the large, roughly circular lake near the center of the image. The line spanning the lake is the Lake Pontchartrain Causeway, the world's longest over water highway bridge. Major portions of the city of New Orleans are below sea level, and although it is protected by levees and sea walls, flooding during storm surges associated with major hurricanes is a significant concern.

    Data used in this image were acquired by the Shuttle Radar Topography Mission aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. The mission used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar that flew twice on the Space Shuttle Endeavour in 1994. The Shuttle Radar Topography Mission was designed to collect 3-D measurements of the Earth's surface. To collect the 3-D data

  4. Estimating Natural Flows into the California's Sacramento - San Joaquin Delta

    NASA Astrophysics Data System (ADS)

    Huang, G.; Kadir, T.; Chung, F. I.

    2014-12-01

    Natural flows into the California's Sacramento - San Joaquin Delta under predevelopment vegetative conditions, if and when reconstructed, can serve as a useful guide to establish minimum stream flows, restoration targets, and a basis for assessing impacts of global warming in the Bay-Delta System. Daily simulations of natural Delta flows for the period 1922-2009 were obtained using precipitation-snowmelt-runoff models for the upper watersheds that are tributaries to the California's Central Valley, and then routing the water through the Central Valley floor area using a modified version of the California Central Valley Groundwater-Surface Water Simulation Model (C2VSIM) for water years 1922 through 2009. Daily stream inflows from all major upper watersheds were simulated using 23 Soil Water Assessment Tool (SWAT) models. Historical precipitation and reference evapotranspiration data were extracted from the SIMETAW2 with the 4km gridded meteorological data. The Historical natural and riparian vegetation distributions were compiled from several pre-1900 historical vegetation maps of the Central Valley. Wetlands were dynamically simulated using interconnected lakes. Flows overtopping natural levees were simulated using flow rating curves. New estimates of potential evapotranspiration from different vegetative classes under natural conditions were also used. Sensitivity simulations demonstrate that evapotranspiration estimates, native vegetation distribution, surface-groundwater interaction parameters, extinction depth for groundwater uptake, and other physical processes play a key role in the magnitude and timing of upstream flows arriving at the Delta. Findings contradict a common misconception that the magnitude of inflows to the Delta under natural vegetative conditions is greater than those under the historical agricultural and urban land use development. The developed models also enable to study the impacts of global warming by modifying meteorological and

  5. Stable isotope deltas: tiny, yet robust signatures in nature.

    PubMed

    Brand, Willi A; Coplen, Tyler B

    2012-09-01

    Although most of them are relatively small, stable isotope deltas of naturally occurring substances are robust and enable workers in anthropology, atmospheric sciences, biology, chemistry, environmental sciences, food and drug authentication, forensic science, geochemistry, geology, oceanography, and paleoclimatology to study a variety of topics. Two fundamental processes explain the stable isotope deltas measured in most terrestrial systems: isotopic fractionation and isotope mixing. Isotopic fractionation is the result of equilibrium or kinetic physicochemical processes that fractionate isotopes because of small differences in physical or chemical properties of molecular species having different isotopes. It is shown that the mixing of radioactive and stable isotope end members can be modelled to provide information on many natural processes, including (14)C abundances in the modern atmosphere and the stable hydrogen and oxygen isotopic compositions of the oceans during glacial and interglacial times. The calculation of mixing fractions using isotope balance equations with isotope deltas can be substantially in error when substances with high concentrations of heavy isotopes (e.g. (13)C, (2)H, and (18)O ) are mixed. In such cases, calculations using mole fractions are preferred as they produce accurate mixing fractions. Isotope deltas are dimensionless quantities. In the International System of Units (SI), these quantities have the unit 1 and the usual list of prefixes is not applicable. To overcome traditional limitations with expressing orders of magnitude differences in isotope deltas, we propose the term urey (symbol Ur), after Harold C. Urey, for the unit 1. In such a manner, an isotope delta value expressed traditionally as-25 per mil can be written as-25 mUr (or-2.5 cUr or-0.25 dUr; the use of any SI prefix is possible). Likewise, very small isotopic differences often expressed in per meg 'units' are easily included (e.g. either+0.015 ‰ or+15 per meg

  6. Salinity Impacts on Agriculture and Groundwater in Delta Regions

    NASA Astrophysics Data System (ADS)

    Clarke, D.; Salehin, M.; Jairuddin, M.; Saleh, A. F. M.; Rahman, M. M.; Parks, K. E.; Haque, M. A.; Lázár, A. N.; Payo, A.

    2015-12-01

    Delta regions are attractive for high intensity agriculture due to the availability of rich sedimentary soils and of fresh water. Many of the world's tropical deltas support high population densities which are reliant on irrigated agriculture. However environmental changes such as sea level rise, tidal inundation and reduced river flows have reduced the quantity and quality of water available for successful agriculture. Additionally, anthropogenic influences such as the over abstraction of ground water and the increased use of low quality water from river inlets has resulted in the accumulation of salts in the soils which diminishes crop productivity. Communities based in these regions are usually reliant on the same water for drinking and cooking because surface water is frequently contaminated by commercial and urban pollution. The expansion of shallow tube well systems for drinking water and agricultural use over the last few decades has resulted in mobilisation of salinity in the coastal and estuarine fringes. Sustainable development in delta regions is becoming constrained by water salinity. However salinity is often studied as an independent issue by specialists working in the fields of agriculture, community water supply and groundwater. The lack of interaction between these disciplines often results in corrective actions being applied to one sector without fully assessing the effects of these actions on other sectors. This paper describes a framework for indentifying the causes and impacts of salinity in delta regions based on the source-pathway-receptor framework. It uses examples and scenarios from the Ganges-Brahmaputra-Meghna delta in Bangladesh together with field measurements and observations made in vulnerable coastal communities. The paper demonstrates the importance of creating an holistic understanding of the development and management of water resources to reduce the impact of salinity in fresh water in delta regions.

  7. The sequence stratigraphy of Upper Carboniferous deltas, western Ireland

    SciTech Connect

    Elliott, T. ); Pulham, A. )

    1991-03-01

    Upper Carboniferous deltaic cyclothems across northern Europe are defined by distinctive faunal concentrate horizons termed 'marine bands' that represent widespread transgressions. Cyclothems in the Namurian Clare basin are approximately 200 m in thickness and comprise an initial thick (up to 150 m) progradational deep-water delta front overlain by smaller scale (5-10 m) bay fills and thick (30-70 m), composite fluvial channels, capped by small to moderate scale (5-35 m) shoreline and/or shallow-water delta fronts. Sand bodies in the delta fronts include isolate, 2-3 km wide mouth-bars, implying that distributary channels were narrow and widely spaced. This contradicts the evidence of the fluvial channel complexes, which are widespread, multilateral bodies up to 25 km wide. In view of these contrasts, the fluvial channels are interpreted as incised valley fills resulting from a relative fall in sea level. The bases of these complexes are interpreted as sequence boundaries; the fluvial channels as lowstand wedges; the overlying shorelines and shallow-water deltas as transgressive systems tracts; and the marine bands as maximum flooding surfaces. Subdivision of the thicker delta fronts into highstand and lowstand components can be made in several ways. Interpretations are dependent on the significance attached to various facies surfaces in these deep-water, possibly shelf-edge delta fronts. The recognition of lowstand, Type 1 sequence boundaries extends the traditional view of the cyclothems as being defined by Frazier-Galloway type flooding surfaces and argues that erosional phases, nondepositional interfluves, and lowstand deep basin deposits should be sought throughout these Upper Carboniferous successions.

  8. Stable isotope deltas: Tiny, yet robust signatures in nature

    USGS Publications Warehouse

    Brand, Willi A.; Coplen, Tyler B.

    2012-01-01

    Although most of them are relatively small, stable isotope deltas of naturally occurring substances are robust and enable workers in anthropology, atmospheric sciences, biology, chemistry, environmental sciences, food and drug authentication, forensic science, geochemistry, geology, oceanography, and paleoclimatology to study a variety of topics. Two fundamental processes explain the stable isotope deltas measured in most terrestrial systems: isotopic fractionation and isotope mixing. Isotopic fractionation is the result of equilibrium or kinetic physicochemical processes that fractionate isotopes because of small differences in physical or chemical properties of molecular species having different isotopes. It is shown that the mixing of radioactive and stable isotope end members can be modelled to provide information on many natural processes, including 14C abundances in the modern atmosphere and the stable hydrogen and oxygen isotopic compositions of the oceans during glacial and interglacial times. The calculation of mixing fractions using isotope balance equations with isotope deltas can be substantially in error when substances with high concentrations of heavy isotopes (e.g. 13C, 2H, and 18O ) are mixed. In such cases, calculations using mole fractions are preferred as they produce accurate mixing fractions. Isotope deltas are dimensionless quantities. In the International System of Units (SI), these quantities have the unit 1 and the usual list of prefixes is not applicable. To overcome traditional limitations with expressing orders of magnitude differences in isotope deltas, we propose the term urey (symbol Ur), after Harold C. Urey, for the unit 1. In such a manner, an isotope delta value expressed traditionally as−25 per mil can be written as−25 mUr (or−2.5 cUr or−0.25 dUr; the use of any SI prefix is possible). Likewise, very small isotopic differences often expressed in per meg ‘units’ are easily included (e.g. either+0.015 ‰ or+15 per meg

  9. Stable isotope deltas: tiny, yet robust signatures in nature.

    PubMed

    Brand, Willi A; Coplen, Tyler B

    2012-09-01

    Although most of them are relatively small, stable isotope deltas of naturally occurring substances are robust and enable workers in anthropology, atmospheric sciences, biology, chemistry, environmental sciences, food and drug authentication, forensic science, geochemistry, geology, oceanography, and paleoclimatology to study a variety of topics. Two fundamental processes explain the stable isotope deltas measured in most terrestrial systems: isotopic fractionation and isotope mixing. Isotopic fractionation is the result of equilibrium or kinetic physicochemical processes that fractionate isotopes because of small differences in physical or chemical properties of molecular species having different isotopes. It is shown that the mixing of radioactive and stable isotope end members can be modelled to provide information on many natural processes, including (14)C abundances in the modern atmosphere and the stable hydrogen and oxygen isotopic compositions of the oceans during glacial and interglacial times. The calculation of mixing fractions using isotope balance equations with isotope deltas can be substantially in error when substances with high concentrations of heavy isotopes (e.g. (13)C, (2)H, and (18)O ) are mixed. In such cases, calculations using mole fractions are preferred as they produce accurate mixing fractions. Isotope deltas are dimensionless quantities. In the International System of Units (SI), these quantities have the unit 1 and the usual list of prefixes is not applicable. To overcome traditional limitations with expressing orders of magnitude differences in isotope deltas, we propose the term urey (symbol Ur), after Harold C. Urey, for the unit 1. In such a manner, an isotope delta value expressed traditionally as-25 per mil can be written as-25 mUr (or-2.5 cUr or-0.25 dUr; the use of any SI prefix is possible). Likewise, very small isotopic differences often expressed in per meg 'units' are easily included (e.g. either+0.015 ‰ or+15 per meg

  10. Hepatitis delta virus mutant: effect on RNA editing.

    PubMed

    Wu, T T; Bichko, V V; Ryu, W S; Lemon, S M; Taylor, J M

    1995-11-01

    During the replication cycle of hepatitis delta virus (HDV), RNA editing occurs at position 1012 on the 1679-nucleotide RNA genome. This changes an A to G in the amber termination codon, UAG, of the small form of the delta antigen (delta Ag). The resultant UGG codon, tryptophan, allows the translation of a larger form of the delta Ag with a 19-amino-acid C-terminal extension. Using HDV cDNA-transfected cells, we examined the editing potential of HDV RNA mutated from G to A at 1011 on the antigenome, adjacent to normal editing site at 1012. Four procedures were used to study not only the editing of the A at 1012, but also that of the new A at 1011: (i) nucleotide sequencing, (ii) a PCR-based RNA-editing assay, (iii) immunoblot assays, and (iv) immunofluorescence. Five findings are reported. (i) Even after the mutation at 1011, editing still occurred at 1012. (ii) Site 1011 itself now acted as a novel RNA-editing site. (iii) Sites 1011 and 1012 were edited independently. (iv) At later times, both sites became edited, thereby allowing the synthesis of the large form of the delta Ag (delta Ag-L). (v) Via immunofluorescence, such double editing became apparent as a stochastic event, in that groups of cells arose in which the changes had taken place. Evaluation of these findings and of those from previous studies of the stability of the HDV genomic sequence (H.J. Netter et al., J. Virol. 69:1687-1692, 1995) supports both the recent reevaluation of HDV RNA editing as occurring on antigenomic RNA (Casey and Gerin, personal communication) and the interpretation that editing occurs via the RNA-modifying enzyme known as DRADA.

  11. Mesospheric ionization and O2 1Delta(g) depletion

    NASA Technical Reports Server (NTRS)

    Spear, K. A.; Solomon, S.

    1987-01-01

    Observations of O2 1Delta(g) emission during solar proton events reveal large depletions below 80 and near 90 km. The lower-altitude depletions are believed to be due to odd hydrogen production and associated depletion of ozone, but the mechanism producing the depletion near 90 km has not yet been established. In this paper, it is proposed that an exothermic charge exchange reaction between O2(+) and O2 1Delta(g) is likely to be responsible for these high-altitude depletions. In particular, it is shown that the vertical structure of the observed change in airglow emission is consistent with this mechanism.

  12. The Delta IV launch table waits for transfer to CCAFS

    NASA Technical Reports Server (NTRS)

    2000-01-01

    In the turn basin near the Vehicle Assembly Building (left) a launch table is docked, waiting for transfer to Launch Complex 37B, Cape Canaveral Air Force Station. The table was fabricated by Jered Industries in Georgia in support of the Delta Evolved Expendable Launch Vehicle (EELV) program, known as Delta IV. It was floated on a barge down the Intercoastal Waterway, through the Barge Canal to the turn basin. The table is approximately 70 feet long, 40 feet wide and 50 feet high, and weighs about 600,000 pounds. Accompanying the launch table on the barge are flame deflectors, which are also to be erected on pad 37B.

  13. An embedded grid formulation applied to a delta wing

    NASA Technical Reports Server (NTRS)

    Krist, Sherrie L.; Thomas, James L.; Sellers, William L., III; Kjelgaard, Scott O.

    1990-01-01

    Applications using a three-dimensional embedded grid scheme are made to high angle of attack viscous flow over two bodies: a slender cone using the conical approximation and a 75 deg swept delta wing. The embedded grids are used principally to improve the numerical resolution of the separated vortical flow above the body. Detailed comparisons are made with experimental measurements of the velocity field over the delta wing. The prediction of the maximum steamwise velocity is improved using two levels of embedded grid refinement but is still less than the experimental measurements available from a laser velocimeter.

  14. Delta-baryon mass in a covariant Faddeev approach

    SciTech Connect

    Nicmorus, D.; Eichmann, G.; Krassnigg, A.; Alkofer, R.

    2009-09-01

    We present a calculation of the three-quark core contribution to the mass of the {delta} resonance in a Poincare-covariant Faddeev framework. A consistent setup for the dressed-quark propagator, the quark-quark and quark-'diquark' interactions is used, where all the ingredients are solutions of their respective Dyson-Schwinger or Bethe-Salpeter equations in rainbow-ladder truncation. We discuss the evolution of the {delta} mass with the current-quark mass and compare to the previously obtained mass of the nucleon.

  15. On the meaning of [Delta]T/T

    SciTech Connect

    Stebbins, A.

    1993-02-01

    One of the most interesting aspects of the discovery of Microwave Background Radiation (MBR) anisotropy by the COBE satellite is the ability to compare these anisotropies with the amplitude of density inhomogeneities we measure. Combining these two, we can get a unified'' view of the inhomogeneities present in our universe on a broad range of scales. To make this comparison we must be able to translate [Delta]T/T into [delta]p/[bar p], the mass overdensity. This latter quantity we may try to determine from the distribution of galaxies and their velocities.

  16. Stability analysis for delta operator systems subject to state saturation

    NASA Astrophysics Data System (ADS)

    Yang, Hongjiu; Geng, Qing; Xia, Yuanqing; Li, Li

    2016-11-01

    In this paper, we investigate the problem of stability analysis for linear delta operator systems subject to state saturation. Both full state saturation and partial state saturation are investigated for the delta operator systems. Two equivalent necessary and sufficient conditions are identified such that the system with full state saturation is globally asymptotically stable. Based on the sufficient conditions, an iterative algorithm is proposed for testing global asymptotic stability of the system with full state saturation. A new globally asymptotically stable condition is also proposed for the partial state saturation system. Two numerical examples on a ball and beam model are given to show the effectiveness of the proposed method.

  17. Identification of E2F1 as a positive transcriptional regulator for {delta}-catenin

    SciTech Connect

    Kim, Kwonseop; Oh, Minsoo; Ki, Hyunkyoung; Wang Tao; Bareiss, Sonja; Fini, M. Elizabeth.; Li Dawei; Lu Qun

    2008-05-02

    {delta}-Catenin is upregulated in human carcinomas. However, little is known about the potential transcriptional factors that regulate {delta}-catenin expression in cancer. Using a human {delta}-catenin reporter system, we have screened several nuclear signaling modulators to test whether they can affect {delta}-catenin transcription. Among {beta}-catenin/LEF-1, Notch1, and E2F1, E2F1 dramatically increased {delta}-catenin-luciferase activities while {beta}-catenin/LEF-1 induced only a marginal increase. Rb suppressed the upregulation of {delta}-catenin-luciferase activities induced by E2F1 but did not interact with {delta}-catenin. RT-PCR and Western blot analyses in 4 different prostate cancer cell lines revealed that regulation of {delta}-catenin expression is controlled mainly at the transcriptional level. Interestingly, the effects of E2F1 on {delta}-catenin expression were observed only in human cancer cells expressing abundant endogenous {delta}-catenin. These studies identify E2F1 as a positive transcriptional regulator for {delta}-catenin, but further suggest the presence of strong negative regulator(s) for {delta}-catenin in prostate cancer cells with minimal endogenous {delta}-catenin expression.

  18. Transmission of the hepatitis B virus-associated delta agent to the eastern woodchuck.

    PubMed Central

    Ponzetto, A; Cote, P J; Popper, H; Hoyer, B H; London, W T; Ford, E C; Bonino, F; Purcell, R H; Gerin, J L

    1984-01-01

    delta agent of human origin was inoculated into four woodchucks chronically infected with woodchuck hepatitis virus (WHV). The animals developed delta infections with serologic patterns similar to those previously observed in human and chimpanzee infections. delta antigen was detected transiently in serum and liver and was followed by seroconversion to anti-delta antibody. Analogous to the chimpanzee model of delta infection, serum and hepatocyte markers of WHV were suppressed in the woodchuck during acute delta infection. The suppression of WHV DNA in serum was evident only during the time of delta-antigen positivity, while the inhibition of other WHV markers was more protracted. The delta antigen in woodchuck sera circulated as an internal component of a particle similar in size to the human delta particle (36-nm diameter) and was encapsidated by the woodchuck hepatitis virus surface antigen; delta antigen from infected woodchuck and chimpanzee livers had similar biophysical properties. Histologic analysis showed that experimental delta infection is associated with a transient acute hepatitis in woodchucks and loss of hepatocytes carrying WHV antigens. The lesions differed from the conspicuous hepatitis associated with reappearance of WHV replication. Hepatitis B-like viruses, therefore, appear to provide the requisite helper functions for delta replication and the woodchuck represents a useful model for study of the virology and pathology of the delta agent. Images PMID:6585793

  19. Integrating Delta Building Physics & Economics: Optimizing the Scale of Engineered Avulsions in the Mississippi River Delta

    NASA Astrophysics Data System (ADS)

    Kenney, M. A.; Mohrig, D.; Hobbs, B. F.; Parker, G.

    2011-12-01

    Land loss in the Mississippi River Delta caused by subsidence and erosion has resulted in habitat loss, interference with human activities, and increased exposure of New Orleans and other settled areas to storm surge risks. Prior to dam and levee building and oil and gas production in the 20th century, the long term rates of land building roughly balanced land loss through subsidence. Now, however, sediment is being deposited at dramatically lower rates in shallow areas in and adjacent to the Delta, with much of the remaining sediment borne by the Mississippi being lost to the deep areas of the Gulf of Mexico. A few projects have been built in order to divert sediment from the river to areas where land can be built, and many more are under consideration as part of State of Louisiana and Federal planning processes. Most are small scale, although there have been some proposals for large engineered avulsions that would divert a significant fraction of the remaining available sediment (W. Kim, et al. 2009, EOS). However, there is debate over whether small or large diversions are the economically optimally and socially most acceptable size of such land building projects. From an economic point of view, the optimal size involves tradeoffs between scale economies in civil work construction, the relationship between depth of diversion and sediment concentration in river water, effects on navigation, and possible diminishing returns to land building at a single location as the edge of built land progresses into deeper waters. Because land building efforts could potentially involve billions of dollars of investment, it is important to gain as much benefit as possible from those expenditures. We present the result of a general analysis of scale economies in land building from engineered avulsions. The analysis addresses the question: how many projects of what size should be built at what time in order to maximize the amount of land built by a particular time? The analysis

  20. 76 FR 62055 - Mississippi Delta Energy Agency, Clarksdale Public Utilities Commission, Public Service...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-06

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Mississippi Delta Energy Agency, Clarksdale Public Utilities Commission... Practice and Procedures, and the applicable Tariff on file with the Commission, Mississippi Delta...

  1. Delta rhythm in wakefulness: evidence from intracranial recordings in human beings.

    PubMed

    Sachdev, Robert N S; Gaspard, Nicolas; Gerrard, Jason L; Hirsch, Lawrence J; Spencer, Dennis D; Zaveri, Hitten P

    2015-08-01

    A widely accepted view is that wakefulness is a state in which the entire cortical mantle is persistently activated, and therefore desynchronized. Consequently, the EEG is dominated by low-amplitude, high-frequency fluctuations. This view is currently under revision because the 1-4 Hz delta rhythm is often evident during "quiet" wakefulness in rodents and nonhuman primates. Here we used intracranial EEG recordings to assess the occurrence of delta rhythm in 18 awake human beings. Our recordings reveal rhythmic delta during wakefulness at 10% of all recording sites. Delta rhythm could be observed in a single cortical lobe or in multiple lobes. Sites with high delta could flip between high and low delta power or could be in a persistently high delta state. Finally, these sites were rarely identified as the sites of seizure onset. Thus rhythmic delta can dominate the background operation and activity of some neocortical circuits in awake human beings.

  2. 75 FR 20598 - Public Buildings Service; Prospect Island, Sacramento Delta, Solano County, CA; Transfer of Property

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-20

    ... From the Federal Register Online via the Government Publishing Office GENERAL SERVICES ADMINISTRATION Public Buildings Service; Prospect Island, Sacramento Delta, Solano County, CA; Transfer of... identified as Prospect Island, Sacramento Delta, Solano County, California to the State of...

  3. 78 FR 71634 - 60-Day Notice of Proposed Information Collection: Delta Community Capital Initiative Application...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-29

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT 60-Day Notice of Proposed Information Collection: Delta Community Capital Initiative... Collection Title of Information Collection: Delta Community Capital Initiative. OMB Approval Number:...

  4. Porous FeOx/BiVO4-deltaS0.08: highly efficient photocatalysts for the degradation of methylene blue under visible-light illumination.

    PubMed

    Zhao, Zhenxuan; Dai, Hongxing; Deng, Jiguang; Liu, Yuxi; Wang, Yuan; Li, Xinwei; Bai, Guangmei; Gao, Baozu; Au, Chak Tong

    2013-10-01

    Porous S-doped bismuth vanadate with an olive-like morphology and its supported iron oxide (y wt.% FeOx/BiVO4-deltaS0.08, y = 0.06, 0.76, and 1.40) photocatalysts were fabricated using the dodecylamine-assisted alcohol-hydrothermal and incipient wetness impregnation methods, respectively. It is shown that the y wt.% FeOx/BiVO4-deltaS0.08 photocatalysts contained a monoclinic scheetlite BiVO4 phase with a porous olive-like morphology, a surface area of 8.8-9.2 m2/g, and a bandgap energy of 2.38-2.42 eV. There was co-presence of surface Bi5+, Bi3+, V5+, V3+, Fe3+, and Fe2+ species in y wt.% FeOx/BiVO4-deltaS0.08. The 1.40 wt.% FeOx/BiVO4-deltaS0.08 sample performed the best for Methylene Blue degradation under visible-light illumination. The photocatalytic mechanism was also discussed. We believe that the sulfur and FeOx co-doping, higher oxygen adspecies concentration, and lower bandgap energy were responsible for the excellent visible-light-driven catalytic activity of 1.40 wt.% FeOx/BiVO4-deltaS0.08. PMID:24494502

  5. Changes in the areal extents of the Athabasca River, Birch River, and Cree Creek Deltas, 1950-2014, Peace-Athabasca Delta, Canada

    NASA Astrophysics Data System (ADS)

    Timoney, Kevin; Lee, Peter

    2016-04-01

    Deltas form where riverborne sediment accumulates at the interface of river mouths and their receiving water bodies. Their areal extent is determined by the net effect of processes that increase their extent, such as sediment accumulation, and processes that decrease their extent, such as erosion and subsidence. Through sequential mapping and construction of river discharge and sediment histories, this study examined changes in the subaerial extents of the Cree Creek and Athabasca River Deltas (both on the Athabasca River system) and the Birch River Delta in northern Canada over the period 1950-2014. The purpose of the study was to determine how, when, and why the deltas changed in areal extent. Temporal growth patterns were similar across the Athabasca and Birch River systems indicative of a climatic signal. Little or no areal growth occurred from 1950 to 1968; moderate growth occurred between 1968 and the early to mid-1980s; and rapid growth occurred between 1992 and 2012. Factors that affected delta progradation included dredging, sediment supply, isostatic drowning, delta front bathymetry, sediment capture efficiency, and storms. In relation to sediment delivered, areal growth rates were lowest in the Athabasca Delta, intermediate in the Birch Delta, and highest in the Cree Creek Delta. Annual sediment delivery is increasing in the Cree Creek Delta; there were no significant trends in annual sediment delivery in the Birch and Athabasca Deltas. There was a lag of up to several years between sediment delivery events and progradation. Periods of delta progradation were associated with low water levels of the receiving basins. Predicted climate-change driven declines in river discharge and lake levels may accelerate delta progradation in the region. In the changing ecosystems of northeastern Alberta, inadequate monitoring of vegetation, landforms, and sediment regimes hampers the elucidation of the nature, rate, and causality of ecosystem changes.

  6. Final Narrative Report on Nursing Ethics at Delta College.

    ERIC Educational Resources Information Center

    Pfeiffer, Raymond S.

    This four-part report describes a project undertaken by Delta College to implement two required bioethics courses for nursing students: an introductory course in ethical theories and an advanced course in applications of these theories in nursing. After Part I relates how funding for the project was secured and used, Part II delineates the…

  7. Functional and pharmacological properties of GABArho1delta51 receptors.

    PubMed

    Demuro, A; Martínez-Torres, A; Miledi, R

    2000-02-01

    Gamma-aminobutyrate is the main inhibitory neurotransmitter in the vertebrate brain, and the gamma-aminobutyric acid (GABA) receptor subunit GABArho1delta51 is an alternatively spliced form of the GABArho1 receptor that was recently isolated from human retina cDNA libraries. The rho1delta51 receptor subunit lacks 17 amino acids in the extracellular N-terminal domain and, when expressed in Xenopus oocytes, forms functional homomeric GABA receptors. Unexpectedly, even after a such a big deletion, the fundamental properties of the deleted variant receptors are very similar to those of the complete GABArho1 receptors. For example, both types of receptors are bicuculline resistant, desensitize very little, and are negatively modulated by Zn2+ and positively modulated by La3+. In spite of such similarities, the GABArho1delta51 receptors are more sensitive to GABA, to the specific GABA(C) antagonist (1,2,5,6-tetrahydropyridine-4-yl)methylphosphinic acid and to Zn2+, than the complete GABArho1 receptors. The GABArho1delta51 receptors extend the variety of inhibitory receptors in the retina. Their functional significance still remains to be determined.

  8. Novel urinary metabolite of d-delta-tocopherol in rats

    SciTech Connect

    Chiku, S.; Hamamura, K.; Nakamura, T.

    1984-01-01

    A novel metabolite of d-delta-tocopherol was isolated from the urine of rats given d-3,4-(/sup 3/H/sub 2/)-delta-tocopherol intravenously. The metabolite was collected from the urine of rats given d-delta-tocopherol in the same manner as that of the labeled compound. It was found that the metabolites consisted of sulfate conjugates. The portion of the major metabolite released with sulfatase was determined to be 2,8-dimethyl-2-(2'-carboxyethyl)-6-chromanol by infrared spectra, nuclear magnetic resonance spectra, and mass spectra. The proposed structure was confirmed by comparing the analytical results with those of a synthetically derived compound. As a result of the structural elucidation of this novel metabolite, a pathway for the biological transformation of delta-tocopherol is proposed which is different from that of alpha-tocopherol. A characteristic feature of the pathway is the absence of any opening of the chroman ring throughout the sequence.

  9. Geologic maps of the Sacramento-San Joaquin Delta, California

    USGS Publications Warehouse

    Atwater, Brian F.

    1982-01-01

    The Sacramento-San Joaquin Delta, the arm of the San Francisco Bay estuary that reaches into the Central Valley of California, differs from typical coastal-plain deltas in three important respects.  First, rather than meeting the ocean individually and directly, all major waterways of this delta discharge via a single constricted outlet into a chain of estuarine bays and straits.  Second, in the most common vertical sequence of deposits, peat and mud deposited in tidal marshes and swamps (tidal wetlands) directly overlie alluvium or eolian sand, a sequence recording a landward spread of tidal environments rather than the seaward migration of fluvial environments that is typical of coastal-plain deltas (Cosby, 1941, p. 43; Thompson, 1957, p. 12; Shlemon and Begg, 1975, p. 259; Atwater and Belknap, 1980).  Finally, intensive human use has led to a peculiar set of conflicts involving rights to water and responsibilities for flood-control levees (Kockelman and other, 1982).

  10. Dermal absorption of the insecticide lindane (1 delta, 2 delta, 3 beta, 4 delta, 5 delta, 6 beta-hexachlorocyclohexane) in rats and rhesus monkeys: effect of anatomical site.

    PubMed

    Moody, R P; Ritter, L

    1989-01-01

    Dermal absorption of the insecticide lindane (1 delta, 2 delta, 3 beta, 4 delta, 5 delta, 6 beta-hexachlorocyclohexane) was determined in rats and rhesus monkeys. Lindane is in widespread use as a 1% cream or lotion scabicide formulation and as a 1% miticide shampoo for body lice control in humans. Results obtained following our in vivo dermal absorption procedure demonstrated that 18 +/- 4.1%, 34 +/- 5.2%, and 54 +/- 26.3% of the applied dose was absorbed following topical applications at a rate of 1.5 micrograms/cm2 (6.2 micrograms/100 microliters of acetone) of the 14C-labeled pesticide to 4.2-cm2 regions of the forearm (n = 8), forehead (n = 7), and palm (n = 4) of rhesus monkeys, respectively. Dose sites were washed with soapy water 24 h posttreatment. Comparative studies in rats (n = 5) dosed middorsally demonstrated 31 +/- 9.5% absorption. Statistical analysis of the 14C excretion kinetics demonstrated slower clearance of lindane from rats than monkey forearm, forehead, or palm. Intramuscular (im) injections of 14C-lindane gave 52 +/- 7.1% recovery in monkey (n = 8) and 64 +/- 5.9% in rats (n = 5), suggesting body storage of this lipophilic chemical.

  11. Review: Advances in delta-subsidence research using satellite methods

    NASA Astrophysics Data System (ADS)

    Higgins, Stephanie A.

    2016-05-01

    Most of the world's major river deltas are sinking relative to local sea level. The effects of subsidence can include aquifer salinization, infrastructure damage, increased vulnerability to flooding and storm surges, and permanent inundation of low-lying land. Consequently, determining the relative importance of natural vs. anthropogenic pressures in driving delta subsidence is a topic of ongoing research. This article presents a review of knowledge with respect to delta surface-elevation loss. The field is rapidly advancing due to applications of space-based techniques: InSAR (interferometric synthetic aperture radar), GPS (global positioning system), and satellite ocean altimetry. These techniques have shed new light on a variety of subsidence processes, including tectonics, isostatic adjustment, and the spatial and temporal variability of sediment compaction. They also confirm that subsidence associated with fluid extraction can outpace sea-level rise by up to two orders of magnitude, resulting in effective sea-level rise that is one-hundred times faster than the global average rate. In coming years, space-based and airborne instruments will be critical in providing near-real-time monitoring to facilitate management decisions in sinking deltas. However, ground-based observations continue to be necessary for generating complete measurements of surface-elevation change. Numerical modeling should seek to simulate couplings between subsidence processes for greater predictive power.

  12. Seismic stability of the Duwamish River Delta, Seattle, Washington

    USGS Publications Warehouse

    Kayen, Robert E.; Barnhardt, Walter A.

    2007-01-01

    The delta front of the Duwamish River valley near Elliott Bay and Harbor Island is founded on young Holocene deposits shaped by sea-level rise, episodic volcanism, and seismicity. These river-mouth deposits are highly susceptible to seismic soil liquefaction and are potentially prone to submarine landsliding and disintegrative flow failure. A highly developed commercial-industrial corridor, extending from the City of Kent to the Elliott Bay/Harbor Island marine terminal facilities, is founded on the young Holocene deposits of the Duwamish River valley. The deposits of this Holocene delta have been shaped not only by relative sea-level rise but also by episodic volcanism and seismicity. Ground-penetrating radar (GPR), cores, in situ testing, and outcrops are being used to examine the delta stratigraphy and to infer how these deposits will respond to future volcanic eruptions and earthquakes in the region. A geotechnical investigation of these river-mouth deposits indicates high initial liquefaction susceptibility during earthquakes, and possibly the potential for unlimited-strain disintegrative flow failure of the delta front.

  13. Validity and reliability of the Delta Healthy Eating Attitudes Scale

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this study was to evaluate psychometric properties of an instrument developed to measure psychosocial factors related to the Dietary Guidelines for Americans for a nutrition intervention in the Lower Mississippi Delta (LMD). Social Cognitive Theory constructs social support (SS), s...

  14. The Nile Delta: climate pacing and vulnerability to Holocene change

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

    Deltas are potentially important sentinels to investigate climate-driven changes in palaeohydrology and human impacts, but, paradoxically, have often been overlooked as palaeoclimate records. In this paper, we present two time-series from the Nile Delta to probe both millennial and centennial-scale changes in deltaic hydrogeomorphology over the past 8000 years. In a global Holocene context, the long-term decrease in Nile Delta accretion rates is consistent with insolation-driven changes in the 'monsoon pacemaker', attested throughout the mid-latitude tropics. Using a second record we suggest that, at shorter timescales, many of the major phases of deltaic modification were mediated by climate events linked to El Niño Southern Oscillation- type (ENSO) variability. In the final part of the paper, we propose that following the early to mid-Holocene growth of the Nile's deltaic plain pronounced deltaic erosion is first recorded after ~4000 years ago, the corollaries of falling sediment supply and an intensification of anthropogenic impacts from the Pharaonic period onwards. The study highlights the importance of the world's deltas as sensitive archives to investigate Holocene geosystem responses to climate change, risks and hazards, and societal interaction.

  15. Ecosystem Services Assessment of the Nemunas River Delta

    EPA Science Inventory

    The concept of ecosystem services recognizes the services, and benefits, provided to people by ecosystems. The Nemunas River Delta, in Lithuania, is a valued area that can provide a range of services. We conducted a meta-analysis of existing studies done on the region to identify...

  16. Delta FUSE Fairing Installation at Launch Complex 17A

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This NASA Kennedy Space Center (KSC) video release presents footage of the June 19, 1999 installation of the fairing around the Far Ultraviolet Spectroscopic Explorer (FUSE) spacecraft. The spacecraft was previously mated to the Boeing Delta II rocket. Installation took place on Pad A of Launch Complex 17.

  17. Recent measurement of {delta}G/G at COMPASS

    SciTech Connect

    Bernet, C

    2005-10-06

    We present a preliminary measurement of the gluon polarization {delta}G/G in the nucleon, based on the spin asymmetry of quasi-real photoproduction events for which a pair of large transverse momentum hadrons is produced. The data were obtained by the COMPASS experiment at CERN using a 160 GeV polarized muon beam scattered on a large polarized 6LiD target. The preliminary helicity asymmetry for the selected events is A{sub paralle}Ll /D = 0.002 {+-} 0.019(stat.) {+-} 0.003(exp.syst.). From this value, a leading order analysis based on the model of PYTHIA leads to the gluon polarization in the nucleon {delta}G/G(xg = 0.095, {mu}2 = 3 GeV2) = 0.024 {+-} 0.089(stat.) {+-} 0.057(syst.). This value is consistent with parameterizations obtained from QCD fits to the g1 data, with a first moment {delta}G {identical_to} {integral}{sub 0}{sup 1} {delta}G(x)dx {approx_equal} 0.5, at the same scale.

  18. Dermal absorption of the insecticide lindane (1 delta, 2 delta, 3 beta, 4 delta, 5 delta, 6 beta-hexachlorocyclohexane) in rats and rhesus monkeys: Effect of anatomical site

    SciTech Connect

    Moody, R.P.; Ritter, L. )

    1989-01-01

    Dermal absorption of the insecticide lindane (1 delta, 2 delta, 3 beta, 4 delta, 5 delta, 6 beta-hexachlorocyclohexane) was determined in rats and rhesus monkeys. Lindane is in widespread use as a 1% cream or lotion scabicide formulation and as a 1% miticide shampoo for body lice control in humans. Results obtained following our in vivo dermal absorption procedure demonstrated that 18 +/- 4.1%, 34 +/- 5.2%, and 54 +/- 26.3% of the applied dose was absorbed following topical applications at a rate of 1.5 micrograms/cm2 (6.2 micrograms/100 microliters of acetone) of the 14C-labeled pesticide to 4.2-cm2 regions of the forearm (n = 8), forehead (n = 7), and palm (n = 4) of rhesus monkeys, respectively. Dose sites were washed with soapy water 24 h posttreatment. Comparative studies in rats (n = 5) dosed middorsally demonstrated 31 +/- 9.5% absorption. Statistical analysis of the 14C excretion kinetics demonstrated slower clearance of lindane from rats than monkey forearm, forehead, or palm. Intramuscular (im) injections of 14C-lindane gave 52 +/- 7.1% recovery in monkey (n = 8) and 64 +/- 5.9% in rats (n = 5), suggesting body storage of this lipophilic chemical.

  19. Quadrupolar, Triple [Delta]-Function Potential in One Dimension

    ERIC Educational Resources Information Center

    Patil, S. H.

    2009-01-01

    The energy and parity eigenstates for quadrupolar, triple [delta]-function potential are analysed. Using the analytical solutions in specific domains, simple expressions are obtained for even- and odd-parity bound-state energies. The Heisenberg uncertainty product is observed to have a minimum for a specific strength of the potential. The…

  20. The effect of interference on delta modulation encoded video signals

    NASA Technical Reports Server (NTRS)

    Schilling, D. L.

    1979-01-01

    An adaptive delta modulator which encodes composite color video signals was shown to provide a good response when operating at 16 Mb/s and near-commercial quality at 23Mb/s. The ADM was relatively immune to channel errors. The system design is discussed and circuit diagrams are included.

  1. Noise Simulation of Continuous-Time {sigma}{delta} Modulators

    SciTech Connect

    Arias, J.; Quintanilla, L.; Bisbal, D.; San Pablo, J.; Enriquez, L.; Vicente, J.; Barbolla, J.

    2005-08-25

    In this work, an approach for the simulation of the effect of noise sources in the performance of continuous-time {delta}{sigma} modulators is presented. Electrical noise including thermal noise, 1/f noise and clock jitter are included in a simulation program and their impact on the system performance is analyzed.

  2. The Problem with the Delta Cost Project Database

    ERIC Educational Resources Information Center

    Jaquette, Ozan; Parra, Edna

    2016-01-01

    The Integrated Postsecondary Education System (IPEDS) collects data on Title IV institutions. The Delta Cost Project (DCP) integrated data from multiple IPEDS survey components into a public-use longitudinal dataset. The DCP Database was the basis for dozens of journal articles and a series of influential policy reports. Unfortunately, a flaw in…

  3. Lee side flow for slender delta wings of finite thickness

    NASA Technical Reports Server (NTRS)

    Szodruch, J. G.

    1980-01-01

    An experimental and theoretical investigation carried out to determine the lee side flow field over delta wings at supersonic speeds is presented. A theoretical method to described the flow field is described, where boundary conditions as a result of the experimental study are needed. The computed flow field with shock induced separation is satisfactory.

  4. Delta XTE Spacecraft Arrives at CCAS Skid Strip

    NASA Technical Reports Server (NTRS)

    1995-01-01

    Footage shows the U.S Air Force Aircraft "Air Mobility Command" approaching, and landing at the Cape Canaveral Air Station Skid Strip (CCAS). The truck carrying the Delta XTE Spacecraft is also shown as it leaves the Air Mobility Command.

  5. Communication performance of the Intel Touchstone DELTA mesh

    SciTech Connect

    Dunigan, T.H.

    1992-01-01

    The communication performance of the i860-based Intel DELTA mesh supercomputer is compared with the Intel iPSC/860 hypercube and the Ncube 6400 hypercube. Single and multiple hop communication bandwidth and latencies are measured. Concurrent communication speeds and speed under network load are also measured. File I/O performance of the mesh-attached Concurrent File System is measured.

  6. [Forest biomass and its dynamics in Pearl River Delta].

    PubMed

    Yang, Kun; Guan, Dong-Sheng

    2007-04-01

    Based on the observation data obtained from 69 sampling sites of different age class forests, and by using biomass expansion factor function, the regression equations of stand biomass and volume of the main forest types in Pearl River Delta were built, and the regional forest biomass and its dynamics were estimated on the basis of forest inventory data. The results showed that most of the forests in Pearl River Delta were of young-medium age, which occupied 80% or more of the total forest area, and their undergrowth biomass accounted for about 33% of the total forest biomass, indicating that the regional forest biomass could be estimated more exactly if undergrowth biomass was fully concerned. In the periods of 1989-1993, 1994-1998 and 1999-2003, the forest biomass in Pearl River Delta increased by 14. 67 x 10(6) t in total, among which, Pinus massoniana forest, evergreen broadleaf forest, and conifer and deciduous mixed forest contributed about 80%. Young-medium age forest biomass accounted for 90% of the total, but the proportion was decreased gradually. The forest area in the Delta almost kept unvaried, and the forest biomass was increasing year after year, with an annual increment of about 1.2%. Better fostering and managing the existing forests is very important to have more forest biomass and better environmental effect that regional forests offered.

  7. Electroencephalographic and behavioral alterations produced by delta-1-tetrahydrocannabinol.

    PubMed

    Hockman, C H; Perrin, R G; Kalant, H

    1971-05-28

    The administration of small doses of Delta(l)-tetrahydrocannabinol to cats with indwelling electrodes produced a disruption of both the electroencephalogram and behavior. Some of these alterations, including the appearance of a high-voltage slow wave electroencephalogram in the awake and moving animal, have been observed in cats that had been administered other drugs known to cause hallucinogenic states in man.

  8. Obesity and Health Risk of Children in the Mississippi Delta

    ERIC Educational Resources Information Center

    Gamble, Abigail; Waddell, Dwight; Ford, M. Allison; Bentley, John P.; Woodyard, Catherine D.; Hallam, Jeffrey S.

    2012-01-01

    Background: Mississippi (MS) Delta adults and youth report obesity rates far exceeding those of the state and nation. State law requires in-school physical activity and nutrition practices to address childhood obesity but does not require evaluation of outcomes, specifically the impact on weight-related outcomes. This paper offers 3 things: (1)…

  9. Overcoming the Education Challenge of Poverty in the Mississippi Delta

    ERIC Educational Resources Information Center

    Rutherford, Angela S.; Hillmer, Tamara; Parker, Ashley

    2011-01-01

    Tunica County, Mississippi, in the heart of the delta, has been home to stagnant academic achievement even as federal and state funds increased. A teacher-focused professional development program through the University of Mississippi helped yield higher scores and national recognition for an elementary school. It also revealed some learnings:…

  10. Climbing Walls and Climbing Tuitions. A Delta Perspective

    ERIC Educational Resources Information Center

    Kirshstein, Rita J.; Kadamus, James A.

    2012-01-01

    High-end amenities like rock climbing walls on college campuses have become an easy target for those attempting to explain rising tuitions. This Delta Perspective looks beyond the media attention surrounding these "frills" to examine more serious questions about spending on campus facilities, college spending in general, and the real drivers of…

  11. Force Measurement on the GLAST Delta II Flight

    NASA Technical Reports Server (NTRS)

    Gordon, Scott; Kaufman, Daniel

    2009-01-01

    This viewgraph presentation reviews the interface force measurement at spacecraft separation of GLAST Delta II. The contents include: 1) Flight Force Measurement (FFM) Background; 2) Team Members; 3) GLAST Mission Overview; 4) Methodology Development; 5) Ground Test Validation; 6) Flight Data; 7) Coupled Loads Simulation (VCLA & Reconstruction); 8) Basedrive Simulation; 9) Findings; and 10) Summary and Conclusions.

  12. Flutter analysis of highly swept delta wings by conventional methods

    NASA Technical Reports Server (NTRS)

    Gibbons, M. D.; Soistmann, D. L.; Bennett, R. M.

    1988-01-01

    The flutter boundaries of six thin highly-swept delta-platform wings have been calculated. Comparisons are made between experimental data and results using several aerodynamic methods. The aerodynamic methods used include a subsonic and supersonic kernel function, second order piston theory, and a transonic small disturbance code. The dynamic equations of motion are solved using analytically calculated mode shapes and frequencies.

  13. "Delta Plots"--A New Way to Visualize Electronic Excitation.

    ERIC Educational Resources Information Center

    Morrison, Harry; And Others

    1985-01-01

    Presents procedures for obtaining and examples of delta plots (a way of illustrating electron density changes associated with electronic excitation). These plots are pedagogically useful for visualizing simple and complex transitions and provide a way of "seeing" the origin of highest occupied molecular orbital (HOMO)-dictated carbonyl…

  14. Evaluation Report: San Joaquin Delta College. Accreditation Report.

    ERIC Educational Resources Information Center

    San Joaquin Delta Coll., Stockton, CA.

    This report represents the findings of the evaluation team that visited San Joaquin Delta College on March 25-28, 1996 for the purpose of validating the college's application for reaffirmation of accreditation. Overall, the team was impressed with the high level of quality inherent throughout the college. However, the team identified a number of…

  15. Planning for the Future at San Joaquin Delta College.

    ERIC Educational Resources Information Center

    San Joaquin Delta Coll., Stockton, CA.

    This planning document provides data on current operations as of January 1994 and goals for the future at San Joaquin Delta College, in California. Section I, presents the context for planning at the college, describing the following major factors shaping the college's future: (1) the population is rapidly expanding; (2) fee increases and…

  16. Three Dimensional Morphodynamic and Vegetation Modeling of Wax Lake Delta

    NASA Astrophysics Data System (ADS)

    Khadka, A. K.; Meselhe, E. A.; Sadid, K. M.

    2013-12-01

    The Wax Lake Delta (WLD) is located at the downstream end of the Wax Lake outlet, approximately 13 miles upstream from Morgan City, Louisiana. In 1942 the United States Army Corps of Engineer (USACE) dredged Wax Lake Outlet channel from lower Atchafalaya River to reduce flood stages at Morgan City. The channel diverts 50% of Atchafalaya River water and sediment to WLD. Since 1942, the WLD has been building seaward due to the deposition of sediment at the channel mouth. Growth of this delta supports the concept of land building via river diversions. A process based morphodynamic model (Delft3D) with the ability to predict evolution of river-dominated deltas is used in this study to further our understanding of land-building and delta growth processes. Initial model bathymetry is prepared based on USACE hydrographic survey of 1998 along with LIDAR survey data for over bank areas. Two continuous gauges at Wax Lake outlet near Calumet and Atchafalaya Bay near Eugene Island are used to assign upstream inflow and outflow boundary conditions, respectively. The model is calibrated and validated for Hydrodynamics and Sediment transport through two sets of field observations for flooded and average conditions. Vertical velocity and suspended sediment profiles made in the channels of the WLD in 2000 and 2001 are used for the model calibration and validation. More comprehensive field observations are being gathered as part of an ongoing study funded by the National Science Foundation (FESD-Delta Dynamics Collaboratory). Data include mutli-beam bathymetric data, velocities, sediment, and nutrient concentrations in the channels as well as on top of the islands. The Delft3D morphodynamic model for WLD provides quantitative information regarding water and sediment distribution among the inter-connected channel bifurcations, the exchange of sediment and nutrients between the channels and islands. The model is being used to investigate the rate of land building and delta growth from

  17. The transmission of low frequency medical data using delta modulation techniques.

    NASA Technical Reports Server (NTRS)

    Arndt, G. D.; Dawson, C. T.

    1972-01-01

    The transmission of low-frequency medical data using delta modulation techniques is described. The delta modulators are used to distribute the low-frequency data into the passband of the telephone lines. Both adaptive and linear delta modulators are considered. Optimum bit rates to minimize distortion and intersymbol interference are discussed. Vibrocardiographic waves are analyzed as a function of bit rate and delta modulator configuration to determine their reproducibility for medical evaluation.

  18. Aqueous Alteration at a Delta in Eastern Libya Montes

    NASA Astrophysics Data System (ADS)

    Bishop, Janice L.; Tirsch, Daniela; Tornabene, Livio L.; Seelos, Frank P.; Erkeling, Gino; Hiesinger, Harald; Jaumann, Ralf

    2015-04-01

    Libya Montes hosts ancient Noachian basalt altered by hydrothermal action from the Isidis impact, olivine- and pyroxene-bearing lavas from the Syrtis volcanic outflows, multiple craters that have excavated these geologic units, and numerous Hesperian-Amazonian-aged fluvial features that carved channels across the surface and may have transported material downward towards Isidis. Mineralogical analyses of a delta region in Eastern Libya Montes using recently available MTR3 CRISM images have revealed the presence of carbonate in additional to Al-, Fe-, and Mg-bearing phyllosilicates. We are investigating the origins of these aqueous components through stratigraphical and morphological analyses. We hypothesize that the carbonate and Fe/Mg-phyllosilicates are alteration products of the ancient basalt and that the Al-smectite formed as a result of the delta and more recent lacustrine or fluvial processes. The Al-smectite spectral features are most consistent with beidellite, which forms at elevated temperatures compared to montmorillonite. We seek to determine if the beidellite likely formed in warm delta waters or if it may have formed via burial diagenesis and was then excavated by the delta. Newly developed CRISM parameters are being utilized for analysis of the MTR3 versions of CRISM images FRT0000B0CB and FRT0001E2F2 in the fan and delta region of eastern Libya Montes. The MTR3 images feature joined short-wavelength and long-wavelength images and improved spectral signals through new atmospheric separation and noise removal techniques. This enables better detection of spectral signatures from small outcrops of aqueous components. We have placed these new CRISM mineral maps over HRSC stereo images to evaluate the stratigraphy of the aqueous components in relation to the ancient basalt and Syrtis lavas as in previous analyses of the central Libya Montes region. Coordinated CRISM-HiRISE views are expected to provide insights into the morphologies of the aqueous units

  19. The functional significance of delta oscillations in cognitive processing.

    PubMed

    Harmony, Thalía

    2013-01-01

    Ample evidence suggests that electroencephalographic (EEG) oscillatory activity is linked to a broad variety of perceptual, sensorimotor, and cognitive operations. However, few studies have investigated the delta band (0.5-3.5 Hz) during different cognitive processes. The aim of this review is to present data and propose the hypothesis that sustained delta oscillations inhibit interferences that may affect the performance of mental tasks, possibly by modulating the activity of those networks that should be inactive to accomplish the task. It is clear that two functionally distinct and potentially competing brain networks can be broadly distinguished by their contrasting roles in attention to the external world vs. the internally directed mentation or concentration. During concentration, EEG delta (1-3.5 Hz) activity increases mainly in frontal leads in different tasks: mental calculation, semantic tasks, and the Sternberg paradigm. This last task is considered a working memory task, but in neural, as well as phenomenological, terms, working memory can be best understood as attention focused on an internal representation. In the Sternberg task, increases in power in the frequencies from 1 to 3.90 Hz in frontal regions are reported. In a Go/No-Go task, power increases at 1 Hz in both conditions were observed during 100-300 ms in central, parietal and temporal regions. However, in the No-Go condition, power increases were also observed in frontal regions, suggesting its participation in the inhibition of the motor response. Increases in delta power were also reported during semantic tasks in children. In conclusion, the results suggest that power increases of delta frequencies during mental tasks are associated with functional cortical deafferentation, or inhibition of the sensory afferences that interfere with internal concentration. These inhibitory oscillations would modulate the activity of those networks that should be inactive to accomplish the task. PMID

  20. Underground and Previously Undiscovered Rivers in the Mississippi Delta

    NASA Astrophysics Data System (ADS)

    Kolker, A.; Breaux, A.; Coleman, D.; Inniss, L. V.; Telfeyan, K.; Kim, J.; Schneider, A.; Allison, M. A.; Cable, J. E.; Johannesson, K. H.

    2013-12-01

    In this study we show that there are large, and previously undiscovered, groundwater pathways by which water from the Mississippi River is transported to the wetlands and estuaries of the Mississippi River Delta. Results from multiple methodologies suggest that the total flux of groundwater to the coastal zone in the Mississippi River Delta averages 1,000 m3 s-1, and can reach 5,000 m3 s-1 at high flow. We suggest that flow preferentially occurs through paleo-crevasse channels, relict bayous, and other buried deposits of permeable and coarse grained material. These conduits were formed during the present and previous stages of the delta cycle, which occurred in historical (102 y) and late Holocene(103 y) times, respectively. Flow is driven by the hydrological head difference between the river and the estuary, which is seasonally variable in magnitudeand can reach 5-8 m during peak river floods. This talk will present data from hydrological budgets that show a missing fraction in the Mississippi River water budget, and a missing source of fresh water to a large estuary. We will show that water levels in wells in New Orleans fluctuate with the stage of the Mississippi River. Data of Rn concentration indicate advective submarine groundwater flow, whereas Ba concentrations suggest geochemical leachates are entering the estuary. Furthermore, seismic data indicate the prevalence of paleochannels and other buried features that could carry flow. Given the importance of deltas to global geochemical budgets, we suggest that these results may be generalizable: submarine groundwater discharge in deltas may prove to be an important but understudied pathway by which dissolved materials are transported from the continents to the ocean.

  1. 78 FR 18308 - Notice of Funding Availability (NOFA) for Delta Health Care Services Grants

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-26

    ... Rural Business--Cooperative Service Notice of Funding Availability (NOFA) for Delta Health Care Services... availability of grant funds through the Delta Health Care Services Grant Program. Pursuant to the 2012 Appropriations Act, $3,000,000 is available to be competitively awarded for the Delta Health Care Services...

  2. Exposure of Delta Smelt to dissolved pesticides in 1998 and 1999

    USGS Publications Warehouse

    Moon, G. Edward; Kuivila, Kathryn; Ruhl, Catherine A.; Schoellhamer, David H.

    2000-01-01

    This article reviews delta smelt habitat and early life stages followed by an explanation of the study design for assessing pesticide exposure. Results show the co-occurrence of multiple pesticides and delta smelt in their native habitat; these results are presented within the context of possible toxic effects to delta smelt. Finally, the annual variability of pesticide distributions is discussed.

  3. 40 CFR 81.122 - Mississippi Delta Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 18 2014-07-01 2014-07-01 false Mississippi Delta Intrastate Air... Air Quality Control Regions § 81.122 Mississippi Delta Intrastate Air Quality Control Region. The Mississippi Delta Intrastate Air Quality Control Region consists of the territorial area encompassed by...

  4. 33 CFR 147.807 - West Delta 143 Platform safety zone.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false West Delta 143 Platform safety... SECURITY (CONTINUED) OUTER CONTINENTAL SHELF ACTIVITIES SAFETY ZONES § 147.807 West Delta 143 Platform safety zone. (a) Description. The West Delta 143 Platform is located at position 28°39′42″ N, 89°33′05″...

  5. 45 CFR 2532.20 - Special Demonstration Project for the Yukon-Kuskokwim Delta of Alaska.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...-Kuskokwim Delta of Alaska. 2532.20 Section 2532.20 Public Welfare Regulations Relating to Public Welfare... § 2532.20 Special Demonstration Project for the Yukon-Kuskokwim Delta of Alaska. (a) Special Demonstration Project for the Yukon-Kuskokwim Delta of Alaska. The President may award grants to, and enter...

  6. 33 CFR 147.807 - West Delta 143 Platform safety zone.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false West Delta 143 Platform safety... SECURITY (CONTINUED) OUTER CONTINENTAL SHELF ACTIVITIES SAFETY ZONES § 147.807 West Delta 143 Platform safety zone. (a) Description. The West Delta 143 Platform is located at position 28°39′42″ N, 89°33′05″...

  7. 33 CFR 147.807 - West Delta 143 Platform safety zone.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false West Delta 143 Platform safety... SECURITY (CONTINUED) OUTER CONTINENTAL SHELF ACTIVITIES SAFETY ZONES § 147.807 West Delta 143 Platform safety zone. (a) Description. The West Delta 143 Platform is located at position 28°39′42″ N, 89°33′05″...

  8. 40 CFR 81.122 - Mississippi Delta Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 18 2012-07-01 2012-07-01 false Mississippi Delta Intrastate Air... Air Quality Control Regions § 81.122 Mississippi Delta Intrastate Air Quality Control Region. The Mississippi Delta Intrastate Air Quality Control Region consists of the territorial area encompassed by...

  9. 33 CFR 147.807 - West Delta 143 Platform safety zone.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false West Delta 143 Platform safety... SECURITY (CONTINUED) OUTER CONTINENTAL SHELF ACTIVITIES SAFETY ZONES § 147.807 West Delta 143 Platform safety zone. (a) Description. The West Delta 143 Platform is located at position 28°39′42″ N, 89°33′05″...

  10. 45 CFR 2532.20 - Special Demonstration Project for the Yukon-Kuskokwim Delta of Alaska.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...-Kuskokwim Delta of Alaska. 2532.20 Section 2532.20 Public Welfare Regulations Relating to Public Welfare... § 2532.20 Special Demonstration Project for the Yukon-Kuskokwim Delta of Alaska. (a) Special Demonstration Project for the Yukon-Kuskokwim Delta of Alaska. The President may award grants to, and enter...

  11. 40 CFR 81.122 - Mississippi Delta Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 17 2011-07-01 2011-07-01 false Mississippi Delta Intrastate Air... Air Quality Control Regions § 81.122 Mississippi Delta Intrastate Air Quality Control Region. The Mississippi Delta Intrastate Air Quality Control Region consists of the territorial area encompassed by...

  12. 75 FR 33694 - Safety Zone; Delta Independence Day Foundation Celebration, Mandeville Island, CA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-15

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Delta Independence Day Foundation... Mandeville Island, CA for the Delta Independence Day Foundation Celebration Fireworks Display. This safety... the event area. Background and Purpose The Delta Independence Day Foundation will sponsor a...

  13. 76 FR 37192 - Lake Providence Port Commission-Trackage Rights Exemption-Delta Southern Railroad, Inc.

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-24

    ... Surface Transportation Board Lake Providence Port Commission--Trackage Rights Exemption--Delta Southern Railroad, Inc. Pursuant to a written trackage rights agreement dated May 26, 2011, Delta Southern Railroad... tracks at the Port with a line it will acquire from DSR. See Delta Southern R.R.--Aban. Exemption--in...

  14. 45 CFR 2532.20 - Special Demonstration Project for the Yukon-Kuskokwim Delta of Alaska.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...-Kuskokwim Delta of Alaska. 2532.20 Section 2532.20 Public Welfare Regulations Relating to Public Welfare... § 2532.20 Special Demonstration Project for the Yukon-Kuskokwim Delta of Alaska. (a) Special Demonstration Project for the Yukon-Kuskokwim Delta of Alaska. The President may award grants to, and enter...

  15. 31 CFR 103.193 - Special measures against Banco Delta Asia.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 1 2010-07-01 2010-07-01 false Special measures against Banco Delta... Law Enforcement Access to Foreign Bank Records § 103.193 Special measures against Banco Delta Asia. (a) Definitions. For purposes of this section: (1) Banco Delta Asia means all branches, offices, and...

  16. 40 CFR 81.122 - Mississippi Delta Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 17 2010-07-01 2010-07-01 false Mississippi Delta Intrastate Air... Air Quality Control Regions § 81.122 Mississippi Delta Intrastate Air Quality Control Region. The Mississippi Delta Intrastate Air Quality Control Region consists of the territorial area encompassed by...

  17. 33 CFR 147.807 - West Delta 143 Platform safety zone.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false West Delta 143 Platform safety... SECURITY (CONTINUED) OUTER CONTINENTAL SHELF ACTIVITIES SAFETY ZONES § 147.807 West Delta 143 Platform safety zone. (a) Description. The West Delta 143 Platform is located at position 28°39′42″ N, 89°33′05″...

  18. 40 CFR 81.122 - Mississippi Delta Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 18 2013-07-01 2013-07-01 false Mississippi Delta Intrastate Air... Air Quality Control Regions § 81.122 Mississippi Delta Intrastate Air Quality Control Region. The Mississippi Delta Intrastate Air Quality Control Region consists of the territorial area encompassed by...

  19. 40 CFR 180.1107 - Delta endotoxin of Bacillus thuringiensis variety kurstaki encapsulated into killed Pseudomonas...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Delta endotoxin of Bacillus... From Tolerances § 180.1107 Delta endotoxin of Bacillus thuringiensis variety kurstaki encapsulated into killed Pseudomonas fluorescens; exemption from the requirement of a tolerance. The delta endotoxin...

  20. 40 CFR 180.1107 - Delta endotoxin of Bacillus thuringiensis variety kurstaki encapsulated into killed Pseudomonas...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Delta endotoxin of Bacillus... From Tolerances § 180.1107 Delta endotoxin of Bacillus thuringiensis variety kurstaki encapsulated into killed Pseudomonas fluorescens; exemption from the requirement of a tolerance. The delta endotoxin...

  1. 45 CFR 2532.20 - Special Demonstration Project for the Yukon-Kuskokwim Delta of Alaska.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...-Kuskokwim Delta of Alaska. 2532.20 Section 2532.20 Public Welfare Regulations Relating to Public Welfare... § 2532.20 Special Demonstration Project for the Yukon-Kuskokwim Delta of Alaska. (a) Special Demonstration Project for the Yukon-Kuskokwim Delta of Alaska. The President may award grants to, and enter...

  2. 40 CFR 180.1107 - Delta endotoxin of Bacillus thuringiensis variety kurstaki encapsulated into killed Pseudomonas...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Delta endotoxin of Bacillus... From Tolerances § 180.1107 Delta endotoxin of Bacillus thuringiensis variety kurstaki encapsulated into killed Pseudomonas fluorescens; exemption from the requirement of a tolerance. The delta endotoxin...

  3. 45 CFR 2532.20 - Special Demonstration Project for the Yukon-Kuskokwim Delta of Alaska.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...-Kuskokwim Delta of Alaska. 2532.20 Section 2532.20 Public Welfare Regulations Relating to Public Welfare... § 2532.20 Special Demonstration Project for the Yukon-Kuskokwim Delta of Alaska. (a) Special Demonstration Project for the Yukon-Kuskokwim Delta of Alaska. The President may award grants to, and enter...

  4. Microstructural Evidence for Conditioning-dependent (delta) -> (alpha)' Transformations in Retained (delta)-phase Pu-Ga

    SciTech Connect

    Jeffries, J R; Blobaum, K M; Wall, M A; Schwartz, A J

    2008-06-16

    The retained {delta} phase of a Pu-1.9 at.% Ga alloy is metastable with respect to the martensitic {delta} {yields} {alpha}{prime} transformation that occurs at low temperatures. This transformation has been shown to proceed by means of an isothermal martensitic mode, but the kinetics of the transformation are atypical. The transformation exhibits a 'double-C' in a time-temperature-transformation diagram, wherein there exist two temperatures where a given amount of transformation occurs in a minimum amount of time. The cause of the double-C kinetics remains uncertain, eliciting proposals of multiple mechanisms, multiple paths, or different morphologies as possible origins. Recently, a 'conditioning' treatment was found to affect the {delta} {yields} {alpha}{prime} transformation, but the underlying mechanism by which the conditioning treatment influences the transformation has not yet been resolved. In this study, microstructural characterization as a function of temperature, time, and conditioning has been employed to illuminate the role of conditioning in the {delta} {yields} {alpha}{prime} transformation. Conditioning is found to enhance transformation in the upper-C and to enable transformation in the lower-C. The data garnered from these experiments suggest that conditioning is intimately linked to nucleation processes and of little consequence to the growth and morphology of the {alpha}{prime} product phase.

  5. Diet quality of a pregnant, primarily African American cohort residing in the Mississippi Delta: Delta Healthy Sprouts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    At no point during a woman’s life is good nutrition more important than during her reproductive years as her dietary choices affect not only her health but also that of her child. Delta Healthy Sprouts is a randomized, controlled, comparative trial testing the impact of two Maternal, Infant, and Ea...

  6. Baseline characteristics of a pregnant, primarily African American cohort residing in the Mississippi Delta: delta healthy sprouts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Inappropriate gestational weight gain (GWG) is associated with adverse maternal and infant outcomes and increased risk for childhood obesity. Interventions designed to optimize maternal GWG may be effective at improving the health of women and their infants. Delta Healthy Sprouts (DHS) is a random...

  7. The importance of large scale flood over the regular sedimentation in delta development: A case study involving Wax lake delta

    NASA Astrophysics Data System (ADS)

    Ullah, M. S.; Kolker, A.; Li, C.

    2011-12-01

    It has been widely hypothesized that catastrophic floods can play an important role in the development of a young and growing delta. This study examines the nature and rate of sediment deposition in the Wax lake delta in the Atchafalaya Basin of Louisiana during the Mississippi River flood of from April, 2011 to June, 2011. We hypothesize that the deposition rate that results from large scales floods in the Mississippi/Atchafalaya river outlets have a greater impact in the Wax lake delta development than the deposition rates that result from typical yearly sedimentation. Preliminary results from the cosmogenic 7Be counts from sediment collected from the delta show distinct regional and local sediment deposition patterns during the flood, and rates that are significantly higher when compared to the sedimentation rate of the last few decades. This application of cosmogenic 7Be to distinguish the sediment deposition rate provides a first-order understanding of the deltaic evolution and stratigraphic sequence development in a high-discharge setting.

  8. Urban growth and environmental impacts in Jing-Jin-Ji, the Yangtze, River Delta and the Pearl River Delta

    NASA Astrophysics Data System (ADS)

    Haas, Jan; Ban, Yifang

    2014-08-01

    This study investigates land cover changes, magnitude and speed of urbanization and evaluates possible impacts on the environment by the concepts of landscape metrics and ecosystem services in China's three largest and most important urban agglomerations: Jing-Jin-Ji, the Yangtze River Delta and the Pearl River Delta. Based on the classifications of six Landsat TM and HJ-1A/B remotely sensed space-borne optical satellite image mosaics with a superior random forest decision tree ensemble classifier, a total increase in urban land of about 28,000 km2 could be detected alongside a simultaneous decrease in natural land cover classes and cropland. Two urbanization indices describing both speed and magnitude of urbanization were derived and ecosystem services were calculated with a valuation scheme adapted to the Chinese market based on the classification results from 1990 and 2010 for the predominant land cover classes affected by urbanization: forest, cropland, wetlands, water and aquaculture. The speed and relative urban growth in Jing-Jin-Ji was highest, followed by the Yangtze River Delta and Pearl River Delta, resulting in a continuously fragmented landscape and substantial decreases in ecosystem service values of approximately 18.5 billion CNY with coastal wetlands and agriculture being the largest contributors. The results indicate both similarities and differences in urban-regional development trends implicating adverse effects on the natural and rural landscape, not only in the rural-urban fringe, but also in the cities' important hinterlands as a result of rapid urbanization in China.

  9. The Study of Switching Overvoltages under Power System Restoration Scenario Using Extended Delta-Bar-Delta Algorithm

    NASA Astrophysics Data System (ADS)

    Sadeghkhani, Iman; Ketabi, Abbas; Feuillet, Rene

    2013-06-01

    This paper presents an intelligent approach to evaluate switching overvoltages during power equipment energization. Switching action is one of the most important issues in power system restoration schemes. This action may lead to overvoltages that can damage some equipment and delay power system restoration. In this work, transient overvoltages caused by power equipment energization are analyzed and estimated using artificial neural network (ANN)-based approach. Three learning algorithms, delta-bar-delta (DBD), extended delta-bar-delta (EDBD), and directed random search (DRS), were used to train the ANNs. In the cases of transformer and shunt reactor energization, ANNs are trained with the worst case scenario of switching angle and remanent flux which reduce the number of required simulations for training ANN. Also, for achieving good generalization capability for developed ANN, equivalent parameters of the network are used as ANN inputs. The simulated results for a partial of 39-bus New England test system, show that the proposed technique can estimate the peak values and duration of switching overvoltages with good accuracy and EDBD algorithm presents best performance.

  10. Projecting Enrollments for Delta College: Explosive Population Growth Will Enlarge and Diversify Delta's Student Body. Research Report.

    ERIC Educational Resources Information Center

    Evans, John W.

    In 1990, a study was conducted at California's San Joaquin Delta Community College (SJDCC) to examine student enrollment trends and to analyze alternative population projections. The purpose of the study was to prepare SJDCC for the fiscal, managerial, and educational challenges which the growing, ethnically diverse population would bring.…

  11. Implications for future survival of delta smelt from four climate change scenarios for the Sacramento–San Joaquin Delta, California

    USGS Publications Warehouse

    Brown, Larry R.; Bennett, William A.; Wagner, R. Wayne; Morgan-King, Tara; Knowles, Noah; Feyrer, Frederick; Schoellhamer, David H.; Stacey, Mark T.; Dettinger, Mike

    2013-01-01

    Changes in the position of the low salinity zone, a habitat suitability index, turbidity, and water temperature modeled from four 100-year scenarios of climate change were evaluated for possible effects on delta smelt Hypomesus transpacificus, which is endemic to the Sacramento–San Joaquin Delta. The persistence of delta smelt in much of its current habitat into the next century appears uncertain. By mid-century, the position of the low salinity zone in the fall and the habitat suitability index converged on values only observed during the worst droughts of the baseline period (1969–2000). Projected higher water temperatures would render waters historically inhabited by delta smelt near the confluence of the Sacramento and San Joaquin rivers largely uninhabitable. However, the scenarios of climate change are based on assumptions that require caution in the interpretation of the results. Projections like these provide managers with a useful tool for anticipating long-term challenges to managing fish populations and possibly adapting water management to ameliorate those challenges.

  12. Ganges-Brahmaputra Delta: Balance of Subsidence, Sea level and Sedimentation in a Tectonically-Active Delta (Invited)

    NASA Astrophysics Data System (ADS)

    Steckler, M. S.; Goodbred, S. L.; Akhter, S. H.; Seeber, L.; Reitz, M. D.; Paola, C.; Nooner, S. L.; DeWolf, S.; Ferguson, E. K.; Gale, J.; Hossain, S.; Howe, M.; Kim, W.; McHugh, C. M.; Mondal, D. R.; Petter, A. L.; Pickering, J.; Sincavage, R.; Williams, L. A.; Wilson, C.; Zumberge, M. A.

    2013-12-01

    Bangladesh is vulnerable to a host of short and long-term natural hazards - widespread seasonal flooding, river erosion and channel avulsions, permanent land loss from sea level rise, natural groundwater arsenic, recurrent cyclones, landslides and huge earthquakes. These hazards derive from active fluvial processes related to the growth of the delta and the tectonics at the India-Burma-Tibet plate junctions. The Ganges and Brahmaputra rivers drain 3/4 of the Himalayas and carry ~1 GT/y of sediment, 6-8% of the total world flux. In Bangladesh, these two great rivers combine with the Meghna River to form the Ganges-Brahmaputra-Meghna Delta (GBMD). The seasonality of the rivers' water and sediment discharge is a major influence causing widespread flooding during the summer monsoon. The mass of the water is so great that it causes 5-6 cm of seasonal elastic deformation of the delta discerned by our GPS data. Over the longer-term, the rivers are also dynamic. Two centuries ago, the Brahmaputra River avulsed westward up to 100 km and has since captured other rivers. The primary mouth of the Ganges has shifted 100s of km eastward from the Hooghly River over the last 400y, finally joining the Brahmaputra in the 19th century. These avulsions are influenced by the tectonics of the delta. On the east side of Bangladesh, the >16 km thick GBMD is being overridden by the Burma Arc where the attempted subduction of such a thick sediment pile has created a huge accretionary prism. The foldbelt is up to 250-km wide and its front is buried beneath the delta. The main Himalayan thrust front is <100 km north, but adjacent to the GBMD is the Shillong Massif, a 300-km long, 2-km high block of uplifted Indian basement that is overthrusting and depressing GBMD sediments to the south. The overthrusting Shillong Massif may represent a forward jump of the Himalayan front to a new plate boundary. This area ruptured in a ~M8 1897 earthquake. Subsidence from the tectonics and differential

  13. Cloning of an emopamil-binding protein (EBP)-like protein that lacks sterol delta8-delta7 isomerase activity.

    PubMed

    Moebius, Fabian F; Fitzky, Barbara U; Wietzorrek, Georg; Haidekker, Alexander; Eder, Andrea; Glossmann, Hartmut

    2003-08-15

    EBP (emopamil-binding protein) is a high-affinity binding protein for [3H]emopamil and belongs to the family of so-called sigma receptors. Mutations that disrupt EBP's 3beta-hydroxysteroid sterol delta8-delta7 isomerase activity (EC 5.3.3.5) impair cholesterol biosynthesis and cause X-chromosomal dominant chondrodysplasia punctata. We identified a human cDNA for a novel EBPL (EBP-like protein) with a calculated mass of 23.2 kDa. Amino acid sequence alignments and phylogenetic analysis revealed that EBPL is distantly related to EBP (31% identity and 52% similarity) and found in animals but not in plants. EBPL is encoded by four exons on human chromosome 13q14.2 covering 30.7 kb, and a partially processed EBPL pseudogene was found on 16q21. The EBPL mRNA was expressed ubiquitously and most abundant in liver, lung and kidney. Upon heterologous expression in yeast EBPL had no detectable 3beta-hydroxysteroid sterol delta8-delta7 isomerase and sigma-ligand-binding activity. Nine out of ten amino acid residues essential for catalytic activity of EBP were conserved in EBPL. Replacement of the only differing residue (EBP-Y111W) reduced catalytic activity of EBP. Transfer of the divergent residue from EBP to EBPL (EBPL-W91Y) and chimaerization of EBP and EBPL at various positions failed to restore catalytic activity of EBPL. Chemical cross-linking induced homodimerization of EBPL and EBP. Whereas mevinolin increased the mRNA for EBP and DHCR7 (delta7-sterol reductase) in HepG2 cells, it had no effect on mRNAs for EBPL and sigma1 receptor, indicating that EBP and EBPL expression are not co-ordinated. We propose that EBPL has a yet-to-be-discovered function other than cholesterol biosynthesis. PMID:12760743

  14. Cloning of an emopamil-binding protein (EBP)-like protein that lacks sterol delta8-delta7 isomerase activity.

    PubMed Central

    Moebius, Fabian F; Fitzky, Barbara U; Wietzorrek, Georg; Haidekker, Alexander; Eder, Andrea; Glossmann, Hartmut

    2003-01-01

    EBP (emopamil-binding protein) is a high-affinity binding protein for [3H]emopamil and belongs to the family of so-called sigma receptors. Mutations that disrupt EBP's 3beta-hydroxysteroid sterol delta8-delta7 isomerase activity (EC 5.3.3.5) impair cholesterol biosynthesis and cause X-chromosomal dominant chondrodysplasia punctata. We identified a human cDNA for a novel EBPL (EBP-like protein) with a calculated mass of 23.2 kDa. Amino acid sequence alignments and phylogenetic analysis revealed that EBPL is distantly related to EBP (31% identity and 52% similarity) and found in animals but not in plants. EBPL is encoded by four exons on human chromosome 13q14.2 covering 30.7 kb, and a partially processed EBPL pseudogene was found on 16q21. The EBPL mRNA was expressed ubiquitously and most abundant in liver, lung and kidney. Upon heterologous expression in yeast EBPL had no detectable 3beta-hydroxysteroid sterol delta8-delta7 isomerase and sigma-ligand-binding activity. Nine out of ten amino acid residues essential for catalytic activity of EBP were conserved in EBPL. Replacement of the only differing residue (EBP-Y111W) reduced catalytic activity of EBP. Transfer of the divergent residue from EBP to EBPL (EBPL-W91Y) and chimaerization of EBP and EBPL at various positions failed to restore catalytic activity of EBPL. Chemical cross-linking induced homodimerization of EBPL and EBP. Whereas mevinolin increased the mRNA for EBP and DHCR7 (delta7-sterol reductase) in HepG2 cells, it had no effect on mRNAs for EBPL and sigma1 receptor, indicating that EBP and EBPL expression are not co-ordinated. We propose that EBPL has a yet-to-be-discovered function other than cholesterol biosynthesis. PMID:12760743

  15. Evaluating mercury biomagnification in fish from a tropical marine environment using stable isotopes (delta13C and delta15N).

    PubMed

    Al-Reasi, Hassan A; Ababneh, Fuad A; Lean, David R

    2007-08-01

    Concentrations of total mercury (T-Hg) and methylmercury (MeHg) were measured in zooplankton and 13 fish species from a coastal food web of the Gulf of Oman, an arm of the Arabian Sea between Oman and Iran. Stable isotope ratios (delta13C and delta15N) also were determined to track mercury biomagnification. The average concentration of T-Hg in zooplankton was 21 +/- 8.0 ng g(-1) with MeHg accounting 10% of T-Hg. Total mercury levels in fish species ranged from 3.0 ng g(-1) (Sardinella longiceps) to 760 ng g(-1) (Rhizoprionodon acutus) with relatively lower fraction of MeHg (72%) than that found in other studies. The average trophic difference (Deltadelta13C) between zooplankton and planktivorous fish (Selar crumenopthalmus, Rastrelliger kanagurta, and S. longiceps) was higher (3.4 per thousandth) than expected, suggesting that zooplankton may not be the main diet or direct carbon source for these fish species. However, further sampling would be required to compensate for temporal changes in zooplankton and the influence of their lipid content. Trophic position inferred by delta15N and and slopes of the regression equations (log10[T-Hg] = 0.13[delta15N] - 3.57 and log10[MeHg] = 0.14[delta15N] - 3.90) as estimates of biomagnification indicate that biomagnification of T-Hg and MeHg was lower in this tropical ocean compared to what has been observed in arctic and temperate ecosystems and tropical African lakes. The calculated daily intake of methylmercury in the diet of local people through fish consumption was well below the established World Health Organization (WHO) tolerable daily intake threshold for most of the fish species except Euthynnus affinis, Epinephelus epistictus, R. acutus, and Thunnus tonggol, illustrating safe consumption of the commonly consumed fish species.

  16. Within-canopy and ozone fumigation effects on delta13C and Delta18O in adult beech (Fagus sylvatica) trees: relation to meteorological and gas exchange parameters.

    PubMed

    Gessler, Arthur; Löw, Markus; Heerdt, Christian; de Beeck, Maarten Op; Schumacher, Johannes; Grams, Thorsten E E; Bahnweg, Günther; Ceulemans, Reinhart; Werner, Herbert; Matyssek, Rainer; Rennenberg, Heinz; Haberer, Kristine

    2009-11-01

    In this study, the effects of different light intensities either in direct sunlight or in the shade crown of adult beech (Fagus sylvatica L.) trees on delta13C and Delta18O were determined under ambient (1 x O3) and twice-ambient (2 x O3) atmospheric ozone concentrations during two consecutive years (2003 and 2004). We analysed the isotopic composition in leaf bulk, leaf cellulose, phloem and xylem material and related the results to (a) meteorological data (air temperature, T and relative humidity, RH), (b) leaf gas exchange measurements (stomatal conductance, g(s); transpiration rate, E; and maximum photosynthetic activity, A(max)) and (c) the outcome of a steady-state evaporative enrichment model. Delta13C was significantly lower in the shade than in the sun crown in all plant materials, whilst Delta18O was increased significantly in the shade than in the sun crown in bulk material and cellulose. Elevated ozone had no effect on delta13C, although Delta18O was influenced by ozone to varied degrees during single months. We observed significant seasonal changes for both parameters, especially in 2004, and also significant differences between the study years. Relating the findings to meteorological data and gas exchange parameters, we conclude that the differences in Delta18O between the sun and the shade crown were predominantly caused by the Péclet effect. This assumption was supported by the modelled Delta18O values for leaf cellulose. It was demonstrated that independent of RH, light-dependent reduction of stomatal conductance (and thus transpiration) and of A(max) can drive the pattern of Delta18O increase with the concomitant decrease of delta13C in the shade crown. The effect of doubling ozone levels on time-integrated stomatal conductance and transpiration as indicated by the combined analysis of Delta18O and delta13C was much lower than the influence caused by the light exposure. PMID:19734546

  17. Alopecia in a Viable Phospholipase C Delta 1 and Phospholipase C Delta 3 Double Mutant

    PubMed Central

    Runkel, Fabian; Hintze, Maik; Griesing, Sebastian; Michels, Marion; Blanck, Birgit; Fukami, Kiyoko; Guénet, Jean-Louis; Franz, Thomas

    2012-01-01

    Background Inositol 1,4,5trisphosphate (IP3) and diacylglycerol (DAG) are important intracellular signalling molecules in various tissues. They are generated by the phospholipase C family of enzymes, of which phospholipase C delta (PLCD) forms one class. Studies with functional inactivation of Plcd isozyme encoding genes in mice have revealed that loss of both Plcd1 and Plcd3 causes early embryonic death. Inactivation of Plcd1 alone causes loss of hair (alopecia), whereas inactivation of Plcd3 alone has no apparent phenotypic effect. To investigate a possible synergy of Plcd1 and Plcd3 in postnatal mice, novel mutations of these genes compatible with life after birth need to be found. Methodology/Principal Findings We characterise a novel mouse mutant with a spontaneously arisen mutation in Plcd3 (Plcd3mNab) that resulted from the insertion of an intracisternal A particle (IAP) into intron 2 of the Plcd3 gene. This mutation leads to the predominant expression of a truncated PLCD3 protein lacking the N-terminal PH domain. C3H mice that carry one or two mutant Plcd3mNab alleles are phenotypically normal. However, the presence of one Plcd3mNab allele exacerbates the alopecia caused by the loss of functional Plcd1 in Del(9)olt1Pas mutant mice with respect to the number of hair follicles affected and the body region involved. Mice double homozygous for both the Del(9)olt1Pas and the Plcd3mNab mutations survive for several weeks and exhibit total alopecia associated with fragile hair shafts showing altered expression of some structural genes and shortened phases of proliferation in hair follicle matrix cells. Conclusions/Significance The Plcd3mNab mutation is a novel hypomorphic mutation of Plcd3. Our investigations suggest that Plcd1 and Plcd3 have synergistic effects on the murine hair follicle in specific regions of the body surface. PMID:22723964

  18. Erosion of the Mekong delta: the role of human activities

    NASA Astrophysics Data System (ADS)

    Anthony, E.; Dussouillez, P.; Goichot, M.; Brunier, G.; Dolique, F.; Nguyen, V.; Loisel, H.; Mangin, A.; Vantrepotte, V.

    2013-12-01

    River deltas are threatened by dams, dykes, flow channelling, and aggregate extraction. These activities outweigh climate change and sea-level rise in causing delta vulnerability1, and will aggravate the impacts to be expected from these effects2. We show here from analysis of: (1) delta channel morphology and sediment budgets, and (2) satellite imagery, that the Mekong delta, considered as the world's third largest, and hitherto strongly prograding, is now in a phase of large-scale erosion. We discuss the mechanistic links involved in erosion and the way these are related to human activities. High-resolution (2.5 m) SPOT 5 images for the years 2003, 2007, 2011/12 covering 405 km of the delta shoreline show an overall retreat rate of over 8 m a year. 75% of the analysed shoreline, i.e., the muddy western sector, is now retreating at rates exceeding 50 m a year in places. The sandy river-mouth sector maintains a semblance of stability, but with strong variations. We attribute erosion to a cascade of morphosedimentary changes linked to sediment mining from the deltaic channels and upstream dam interception. We estimated from Meris satellite imagery an annual 5% decrease in surface suspended concentrations exiting at the mouths of the Mekong over the period 2003-2011 that may reflect increased trapping of mud behind dams in China. We also infer modification of river-mouth and coastal mud storage patterns resulting from a loss of ca. 200 million m3 of delta channel sediments between 1998 and 2008 from aggregate extraction. Dykes have been shown to result in increased channel flow velocities during the high-discharge monsoon season, favouring further channel deepening3. Stronger river-mouth outflow velocities during this season may be leading to export of a greater proportion of mud far offshore of the coastal longshore transport corridor that ensured mud supply to, and past progradation of, the muddy western coast. In contrast, greater seawater penetration in the

  19. Experimental evidence of a delta-shock in nonlinear chromatography

    SciTech Connect

    Gritti, Fabrice; Guiochon, Georges A

    2010-01-01

    We report about a new type of composition front in nonlinear chromatography that is called delta-shock, which has to be added to the family of classical transitions, i.e. simple waves, shocks and semi-shocks. Recently, the occurrence of delta-shocks in the case of mixed competitive-cooperative isotherms of the following type n{sub i} = H{sub i}c{sub i}/1 = K{sub 1}c{sub 1} + K{sub 2}c{sub 2} (i = 1,2), (with H{sub 2} > H{sub 1}, where components 1 and 2 have anti-Langmuir and Langmuir adsorption behavior, respectively) was predicted theoretically and their behavior was analyzed in the frame of the equilibrium theory of chromatography. The delta-shock can be viewed as a growing traveling spike superimposed to the discontinuity separating the initial and the feed state, which propagates along the column at constant speed and constant rate of growth. In this work we complement these findings from an experimental point of view. The binary system consisting of phenetole (component 1) and 4-tert-butylphenol (component 2) in methanol-water (about 2:1, v/v) on a Zorbax 300StableBond-C18 column from Agilent has been shown, through a series of overloaded pulse experiments and of frontal analysis experiments with the pure compounds, to be subject to the competitive-cooperative isotherm of the type above, up to rather large concentrations. This system does exhibit adelta-shock when the operating conditions are chosen according to theory, namely when phenetole initially saturating the column is displaced by 4-tert-butylphenol, both at high concentrations (the minimum concentrations exhibiting a fully developed delta-shock in this series of experiments were c{sub 1} = 20 g/L and c{sub 2} = 75 g/L). The propagation of the delta-shock matches the theoretical predictions in terms of both the effect of concentration and the effect of column length. This is the first experimental observation ever of adelta-shock in chromatography. It is noteworthy that the proof of the occurrence of

  20. Investigations of (Delta)14C, (delta)13C, and (delta)15N in vertebrae of white shark (Carcharodon carcharias) from the eastern North Pacific Ocean

    SciTech Connect

    Kerr, L A; Andrews, A H; Cailliet, G M; Brown, T A; Coale, K H

    2006-06-08

    The white shark (Carcharodon carcharias) has a complex life history that is characterized by large scale movements and a highly variable diet. Estimates of age and growth for the white shark from the eastern North Pacific Ocean indicate they have a slow growth rate and a relatively high longevity. Age, growth, and longevity estimates useful for stock assessment and fishery models, however, require some form of validation. By counting vertebral growth band pairs, ages can be estimated, but because not all sharks deposit annual growth bands and many are not easily discernable, it is necessary to validate growth band periodicity with an independent method. Radiocarbon ({sup 14}C) age validation uses the discrete {sup 14}C signal produced from thermonuclear testing in the 1950s and 1960s that is retained in skeletal structures as a time-specific marker. Growth band pairs in vertebrae, estimated as annual and spanning the 1930s to 1990s, were analyzed for {Delta}{sup 14}C and stable carbon and nitrogen isotopes ({delta}{sup 13}C and {delta}{sup 15}N). The aim of this study was to evaluate the utility of {sup 14}C age validation for a wide-ranging species with a complex life history and to use stable isotope measurements in vertebrae as a means of resolving complexity introduced into the {sup 14}C chronology by ontogenetic shifts in diet and habitat. Stable isotopes provided useful trophic position information; however, validation of age estimates was confounded by what may have been some combination of the dietary source of carbon to the vertebrae, large-scale movement patterns, and steep {sup 14}C gradients with depth in the eastern North Pacific Ocean.

  1. Chiral effective-field theory in the {delta}(1232) region. II. Radiative pion photoproduction

    SciTech Connect

    Pascalutsa, Vladimir; Vanderhaeghen, Marc

    2008-01-01

    We present a theoretical study of the radiative pion photoproduction on the nucleon ({gamma}N{yields}{pi}N{gamma}{sup '}) in the {delta}-resonance region, with the aim to determine the magnetic dipole moment (MDM) of the {delta}{sup +}(1232). The study is done within the framework of chiral effective-field theory, where the expansion is performed (to next-to-leading order) in the {delta} power-counting scheme, an extension of chiral perturbation theory to the {delta}-resonance energy region. We present the results for the absorptive part of the {delta} MDM, as well as perform a sensitivity study of the dependence of {gamma}N{yields}{pi}N{gamma}{sup '} observables on the real part of the {delta} MDM. We find that an asymmetry for circular polarization of the photon beam may provide a model-independent way to measure the {delta} MDM.

  2. Theoretical confirmation of a 4-Delta ground state for FeH

    NASA Technical Reports Server (NTRS)

    Bauschlicher, Charles W., Jr.; Langhoff, Stephen R.

    1988-01-01

    Large CAS SCF/multireference configuration interaction (MRCI) and modified coupled pair functional (MCPF) calculations are carried out for the 4-Delta and 6-Delta states of FeH using very large Gaussian basis sets. At the MCPF level, 3s and 3p correlation preferentially lowers the 4-Delta state by 0.10 eV. Adding this inner-shell correlation effect to our best CAS SCF/MRCI+Q valence treatment results in a 4-Delta-6 Delta separation of 0.16 eV. This supports the interpretation of the photodetachment spectra of Stevens et al. (1983) that places the 6-Delta state about 0.25 eV above the 4-Delta ground state.

  3. Casscf/ci Calculations for First Row Transition Metal Hydrides - the TIH(4-PHI), VH(5-DELTA), CRH(6-SIGMA-PLUS), MNH(7-SIGMA-PLUS), FEH(4,6-DELTA) and NIH(2-DELTA) States

    NASA Astrophysics Data System (ADS)

    Walch, S. P.; Bauschlicher, C. W., Jr.

    1983-04-01

    Calculations are performed for the predicted ground states of TiH(4-phi), VH(5-delta), CrH(6-sigma-plus), MnH(7-sigma-plus), Fett(4,6-delta) and NiH(2-delta). For FeH both the 6-delta and 4-delta states are studied, since both are likely candidates for the ground state. The ground state symmetries are predicted based on a combination of atomic coupling arguments and coupling of 4s(2)3d(n) and 4s(1)3d(n+1) terms in the molecular system. Electron correlation is included by a CASSCF/CI (SD) treatment. The CASSCF includes near-degeneracy effects, while correlation of the 3d electrons in included at the CI level.

  4. REM and delta sleep in anorexia nervosa and bulimia.

    PubMed

    Levy, A B; Dixon, K N; Schmidt, H

    1987-03-01

    Several recent investigations have suggested that neurobiological similarities may exist between patients with eating disorders and those with depression. We performed polysomnograms for two consecutive nights on nine bulimic and six anorectic patients who had no concomitant diagnosis of endogenous depression. The rapid eye movement (REM) latency, REM density, and delta sleep of these subjects on night 2 were compared to those of 10 healthy controls of similar ages. Contrary to reports of shortened REM latency and increased REM density in depressed patients, we did not find significant REM differences between eating disorder patients without endogenous depression and healthy control subjects. Low weight anorectics did appear to have less delta sleep than did controls. These findings do not support the contention that eating disorders are variants of affective disorders.

  5. An experimental investigation of apex fence flaps on delta wings

    NASA Technical Reports Server (NTRS)

    Vess, R. J.; Wahls, R. A.; Moskovitz, C. A.

    1985-01-01

    The effects on leading edge vortex formation produced by apex fences mounted on two delta wings were examined in a subsonic wind tunnel. Pressure data were collected on the upper surface of the test wings and oil flow and bubble flow visualizations were performed. The deflections studied were 74, 90 and 65 deg in one-sided and two-sided configurations. Full span and semi-span delta wing planforms were used. Relatively small, symmetrically deployed apex fences provided enhanced upper surface suction which, in some angle-of-attack situations, could lead to a pitch-up force. Asymmetrically-deployed fences showed promise for yaw control at high angles of attack, althouh the force effectiveness has yet to be quantified.

  6. Digital Pixel Sensor Array with Logarithmic Delta-Sigma Architecture

    PubMed Central

    Mahmoodi, Alireza; Li, Jing; Joseph, Dileepan

    2013-01-01

    Like the human eye, logarithmic image sensors achieve wide dynamic range easily at video rates, but, unlike the human eye, they suffer from low peak signal-to-noise-and-distortion ratios (PSNDRs). To improve the PSNDR, we propose integrating a delta-sigma analog-to-digital converter (ADC) in each pixel. An image sensor employing this architecture is designed, built and tested in 0.18 micron complementary metal-oxide-semiconductor (CMOS) technology. It achieves a PSNDR better than state-of-the-art logarithmic sensors and comparable to the human eye. As the approach concerns an array of many ADCs, we use a small-area low-power delta-sigma design. For scalability, each pixel has its own decimator. The prototype is compared to a variety of other image sensors, linear and nonlinear, from industry and academia. PMID:23959239

  7. A pilot project: Antioch Delta Cove, Antioch, California

    SciTech Connect

    Minder, M.

    1994-12-31

    The project involves the restoration of the Hickmott cannery site, comprising approximately 15 acres (three five acre parcels) located on the Delta in inter-city Antioch. Hickmott Foods, Inc., operated a fruit and vegetable cannery between 1905 and the early 1970`s, during which time tomato skins, peach and apricot pits, and asparagus butts were discharged on the site. The decaying fruit pits have caused cyanide contamination. Additionally, the site contains some petroleum hydrocarbon contamination as well as gypsum board contamination, apparently from nearby manufacturing operations. The Antioch Delta Cove Pilot shows how interested parties can work together to clean up contaminated sites and use the clean up process to stimulate technology transfer. The Antioch project is a blueprint that can be replicated at other sites across California.

  8. Search for Delta S = 2 nonleptonic hyperon decays

    SciTech Connect

    White, C.G.; Burnstein, R.A.; Chakravorty, A.; Chan, A.; Chen, Y.C.; Choong, W.S.; Clark, K.; Dukes, E.C.; Durandet, C.; Felix, J.; Gidal, G.; Gu, P.; Gustafson, H.R.; Ho, C.; Holmstrom, T.; Huang, M.; James, C.; Jenkins, C.M.; Kaplan, D.M.; Lederman, L.M.; Leros, N.; /Taiwan, Inst. Phys. /UC, Berkeley /Fermilab /Guanajuato U. /IIT, Chicago /Lausanne U. /LBL, Berkeley /Michigan U. /South Alabama U. /Virginia U.

    2005-03-01

    A sensitive search for the rare decays {Omega}{sup -} {yields} {Lambda}{pi}{sup -} and {Xi}{sup 0} {yields} p{pi}{sup -} has been performed using data from the 1997 run of the HyperCP (Fermilab E871) experiment. Limits on other such processes do not exclude the possibility of observable rates for |{Delta}S| = 2 nonleptonic hyperon decays, provided the decays occur through parity-odd operators. They obtain the branching-fraction limits {Beta}({Omega}{sup -} {yields} {Lambda}{pi}{sup -}) < 2.9 x 10{sup -6} and {Beta}({Xi}{sup 0} {yields} p{pi}{sup -}) < 8.2 x 10{sup -6}, both at 90% confidence level.

  9. The Delta IV launch table waits for transfer to CCAFS

    NASA Technical Reports Server (NTRS)

    2000-01-01

    A launch table fabricated by Jered Industries in Georgia is ready for transfer to Launch Complex 37B, Cape Canaveral Air Force Station, after being stabilized aboard the barge that brought it to the turn basin in KSC's Launch Complex 39 Area. In the background is the Vehicle Assembly Building. The table was built in support of the Delta Evolved Expendable Launch Vehicle (EELV) program, known as Delta IV. It was floated on the barge down the Intercoastal Waterway, through the Barge Canal to the turn basin. The table is approximately 70 feet long, 40 feet wide and 50 feet high, and weighs about 600,000 pounds. Accompanying the launch table on the barge are flame deflectors, which are also to be erected on pad 37B.

  10. The Delta IV launch table begins transfer to CCAFS

    NASA Technical Reports Server (NTRS)

    2000-01-01

    A launch table, fabricated by Jered Industries in Georgia for Boeing, turns the corner away from the barge that brought it to the turn basin in KSC's Launch Complex 39 Area. In the background is the Vehicle Assembly Building. The table was built in support of the Delta Evolved Expendable Launch Vehicle (EELV) program, known as Delta IV. It was floated on the barge down the Intercoastal Waterway, through the Barge Canal to the turn basin. The table, whcih is approximately 70 feet long, 40 feet wide and 50 feet high, weighing about 600,000 pounds, is being transferred to Launch Complex 37B, Cape Canaveral Air Force Station. Accompanying the launch table on the barge are flame deflectors, which are also to be erected on pad 37B.

  11. The Delta IV launch table waits for transfer to CCAFS

    NASA Technical Reports Server (NTRS)

    2000-01-01

    A launch table fabricated by Jered Industries in Georgia is ready for transfer to Launch Complex 37B, Cape Canaveral Air Force Station, after being moved off the barge that brought it to the turn basin in KSC's Launch Complex 39 Area. In the background is the Vehicle Assembly Building. The table was built in support of the Delta Evolved Expendable Launch Vehicle (EELV) program, known as Delta IV. It was floated on the barge down the Intercoastal Waterway, through the Barge Canal to the turn basin. The table is approximately 70 feet long, 40 feet wide and 50 feet high, and weighs about 600,000 pounds. Accompanying the launch table on the barge are flame deflectors, which are also to be erected on pad 37B.

  12. The Delta IV launch table waits for transfer to CCAFS

    NASA Technical Reports Server (NTRS)

    2000-01-01

    A launch table fabricated by Jered Industries in Georgia waits for transfer to Launch Complex 37B, Cape Canaveral Air Force Station, after being moved off the barge that brought it to the turn basin in KSC's Launch Complex 39 Area. In the background is the Vehicle Assembly Building. The table was built in support of the Delta Evolved Expendable Launch Vehicle (EELV) program, known as Delta IV. It was floated on the barge down the Intercoastal Waterway, through the Barge Canal to the turn basin. The table is approximately 70 feet long, 40 feet wide and 50 feet high, and weighs about 600,000 pounds. Accompanying the launch table on the barge are flame deflectors, which are also to be erected on pad 37B.

  13. Survivin isoform Delta Ex3 regulates tumor spheroid formation.

    PubMed

    Espinosa, Magali; Ceballos-Cancino, Gisela; Callaghan, Richard; Maldonado, Vilma; Patiño, Nelly; Ruíz, Víctor; Meléndez-Zajgla, Jorge

    2012-05-01

    Survivin is an important member of the Inhibitor of Apoptosis Proteins (IAPs) family and has essential roles in apoptosis and cell cycle progression. This gene is commonly upregulated in human cancer and provides an exciting diagnostic and therapeutic target. Survivin is expressed as several isoforms that are generated by alternative splicing, and some of these present antagonistic activities. Currently, information regarding the regulation of these isoforms is lacking. In this study, we sought to analyze survivin Delta Ex3 expression in a three-dimensional model of avascular tumors and its overexpression effects in processes such as proliferation, clonogenicity and apoptosis. We found a positive correlation between spheroid growth and survivin Delta Ex3 expression during the exponential phase. We demonstrated that this isoform not only decreased apoptosis but also inhibited tumor spheroid formation by decreasing proliferation and clonogenic survival. These results point toward a dual and antagonistic effect of this spliced survivin isoform in cancer development.

  14. Defect Based Spin Mediation in Delta-Phase Plutonium

    SciTech Connect

    Fluss, M J; Wirth, B D; Wall, M; Felter, T E; Caturla, M J; Kubota, A; Diaz de la Rubia, T

    2003-11-19

    We earlier reported the measured decrease of electrical resistivity during isochronal-annealing of ion irradiation damage that was accumulated at low-temperature (10 or 20K), and the temperature dependence of the resistance of defect-populations produced by low-temperature damage-accumulation and annealing in a stabilized {delta}-phase plutonium alloy, Pu(3.3 at%Ga)[1]. We noted that the temperature dependence of the resistance of defects resulting from low-temperature damage accumulation and subsequent annealing exhibits a -ln(T) temperature dependence suggestive of a Kondo impurity. A discussion of a possible ''structure-property'' effect, as it might relate to the nature of the {delta}-phase of Pu, is presented.

  15. Faster embryonic segmentation through elevated Delta-Notch signalling

    PubMed Central

    Liao, Bo-Kai; Jörg, David J.; Oates, Andrew C.

    2016-01-01

    An important step in understanding biological rhythms is the control of period. A multicellular, rhythmic patterning system termed the segmentation clock is thought to govern the sequential production of the vertebrate embryo's body segments, the somites. Several genetic loss-of-function conditions, including the Delta-Notch intercellular signalling mutants, result in slower segmentation. Here, we generate DeltaD transgenic zebrafish lines with a range of copy numbers and correspondingly increased signalling levels, and observe faster segmentation. The highest-expressing line shows an altered oscillating gene expression wave pattern and shortened segmentation period, producing embryos with more, shorter body segments. Our results reveal surprising differences in how Notch signalling strength is quantitatively interpreted in different organ systems, and suggest a role for intercellular communication in regulating the output period of the segmentation clock by altering its spatial pattern. PMID:27302627

  16. Recognizing environments in the deposits of the Niger delta

    SciTech Connect

    Oboh, F.E. )

    1991-03-01

    The paralic sediments of the Agbada Formation are the targets of commercial exploration and exploitation of oil and gas in the Niger delta. Sedimentological and microfossil data from a middle Miocene reservoir in the delta have revealed a succession of deltaic subenvironments of deposition within a prograding offlap sequence. Ten lithofacies, comprising five sandstone, three heterolithic, and two mudstone types, are recognized from grain size, sedimentary structures, and trace fossils in two cored boreholes. Fourteen palynodebris types, including amorphous organic matter, various types of palynomorphs, and wood, were identified in the sediments. These components were subjected to principal component analysis and cluster analysis. The resulting palynofacies are integrated with lithofacies and paleoecological inferences made from the palynomorph and foraminifera contents of the sediments for paleoenvironmental reconstruction. Gamma-ray log correlation of the reservoir in uncored boreholes was carried out, using information from the cores, and this has resulted in a depositional model.

  17. Vegetation mapping from ERTS imagery of the Okavango Delta. [Botswana

    NASA Technical Reports Server (NTRS)

    Willamson, D. T.

    1974-01-01

    The Okavango is Botswana's major water resource. The present study has been specifically directed at mapping vegetation types within the delta and generally concerned with finding what information of value to plant and animal ecologists could be extracted from the imagery. To date it has been found that. (1) It is possible to map broad vegetation types from the imagery. (2) Imagery of the delta records the state of the system in a manner which will facilitate long-term studies of plant succession. (3) Phenological events can be detected. (4) The imagery can be used to detect and map wild fires. This will be useful in determining the role of fire in the ecology of the region. Using the imagery it is thus possible to map existing vegetation and monitor both short and long-term changes.

  18. Mars Polar Lander is mated with Boeing Delta II rocket

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Workers mate the Mars Polar Lander (top) to the Boeing Delta II rocket at Launch Complex 17B, Cape Canaveral Air Station. The rocket is scheduled to launch Jan. 3, 1999. The lander is a solar-powered spacecraft designed to touch down on the Martian surface near the northern- most boundary of the south pole in order to study the water cycle there. The lander also will help scientists learn more about climate change and current resources on Mars, studying such things as frost, dust, water vapor and condensates in the Martian atmosphere. It is the second spacecraft to be launched in a pair of Mars Surveyor '98 missions. The first is the Mars Climate Orbiter, which was launched aboard a Delta II rocket from Launch Complex 17A on Dec. 11, 1998.

  19. Mars Polar Lander is mated with Boeing Delta II rocket

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Inside the gantry at Launch Complex 17B, Cape Canaveral Air Station, the Mars Polar Lander spacecraft is lowered to mate it with the Boeing Delta II rocket that will launch it on Jan. 3, 1999. The lander is a solar-powered spacecraft designed to touch down on the Martian surface near the northern-most boundary of the south pole in order to study the water cycle there. The lander also will help scientists learn more about climate change and current resources on Mars, studying such things as frost, dust, water vapor and condensates in the Martian atmosphere. It is the second spacecraft to be launched in a pair of Mars Surveyor'98 missions. The first is the Mars Climate Orbiter, which was launched aboard a Delta II rocket from Launch Complex 17A on Dec. 11, 1998.

  20. Mars Polar Lander is mated with Boeing Delta II rocket

    NASA Technical Reports Server (NTRS)

    1998-01-01

    At Launch Complex 17B, Cape Canaveral Air Station, workers get ready to remove the protective wrapping on the Mars Polar Lander to be launched aboard a Boeing Delta II rocket on Jan. 3, 1999. The lander is a solar-powered spacecraft designed to touch down on the Martian surface near the northern-most boundary of the south pole in order to study the water cycle there. The lander also will help scientists learn more about climate change and current resources on Mars, studying such things as frost, dust, water vapor and condensates in the Martian atmosphere. It is the second spacecraft to be launched in a pair of Mars Surveyor'98 missions. The first is the Mars Climate Orbiter, which was launched aboard a Delta II rocket from Launch Complex 17A on Dec. 11, 1998.