The Functional Resonance Analysis Method for a systemic risk based environmental auditing in a sinter plant: A semi-quantitative approach

DOE Office of Scientific and Technical Information (OSTI.GOV)

Patriarca, Riccardo, E-mail: riccardo.patriarca@uniroma1.it; Di Gravio, Giulio; Costantino, Francesco

Environmental auditing is a main issue for any production plant and assessing environmental performance is crucial to identify risks factors. The complexity of current plants arises from interactions among technological, human and organizational system components, which are often transient and not easily detectable. The auditing thus requires a systemic perspective, rather than focusing on individual behaviors, as emerged in recent research in the safety domain for socio-technical systems. We explore the significance of modeling the interactions of system components in everyday work, by the application of a recent systemic method, i.e. the Functional Resonance Analysis Method (FRAM), in order tomore » define dynamically the system structure. We present also an innovative evolution of traditional FRAM following a semi-quantitative approach based on Monte Carlo simulation. This paper represents the first contribution related to the application of FRAM in the environmental context, moreover considering a consistent evolution based on Monte Carlo simulation. The case study of an environmental risk auditing in a sinter plant validates the research, showing the benefits in terms of identifying potential critical activities, related mitigating actions and comprehensive environmental monitoring indicators. - Highlights: • We discuss the relevance of a systemic risk based environmental audit. • We present FRAM to represent functional interactions of the system. • We develop a semi-quantitative FRAM framework to assess environmental risks. • We apply the semi-quantitative FRAM framework to build a model for a sinter plant.« less

Impacts of Changed Extratropical Storm Tracks on Arctic Sea Ice Export through Fram Strait

NASA Astrophysics Data System (ADS)

Wei, J.; Zhang, X.; Wang, Z.

2017-12-01

Studies have indicated a poleward shift of extratropical storm tracks and intensification of Arctic storm activities, in particular on the North Atlantic side of the Arctic Ocean. To improve understanding of dynamic effect on changes in Arctic sea ice mass balance, we examined the impacts of the changed storm tracks and activities on Arctic sea ice export through Fram Strait through ocean-sea ice model simulations. The model employed is the high-resolution Massachusetts Institute of Technology general circulation model (MITgcm), which was forced by the Japanese 25-year Reanalysis (JRA-25) dataset. The results show that storm-induced strong northerly wind stress can cause simultaneous response of daily sea ice export and, in turn, exert cumulative effects on interannual variability and long-term changes of sea ice export. Further analysis indicates that storm impact on sea ice export is spatially dependent. The storms occurring southeast of Fram Strait exhibit the largest impacts. The weakened intensity of winter storms in this region after 1994/95 could be responsible for the decrease of total winter sea ice export during the same time period.

Arctic Ocean outflow and glacier-ocean interactions modify water over the Wandel Sea shelf (northeastern Greenland)

NASA Astrophysics Data System (ADS)

Dmitrenko, Igor A.; Kirillov, Sergey A.; Rudels, Bert; Babb, David G.; Toudal Pedersen, Leif; Rysgaard, Søren; Kristoffersen, Yngve; Barber, David G.

2017-12-01

The first-ever conductivity-temperature-depth (CTD) observations on the Wandel Sea shelf in northeastern Greenland were collected in April-May 2015. They were complemented by CTDs taken along the continental slope during the Norwegian FRAM 2014-2015 drift. The CTD profiles are used to reveal the origin of water masses and interactions with ambient water from the continental slope and the tidewater glacier outlet. The subsurface water is associated with the Pacific water outflow from the Arctic Ocean. The underlying halocline separates the Pacific water from a deeper layer of polar water that has interacted with the warm Atlantic water outflow through the Fram Strait, recorded below 140 m. Over the outer shelf, the halocline shows numerous cold density-compensated intrusions indicating lateral interaction with an ambient polar water mass across the continental slope. At the front of the tidewater glacier outlet, colder and turbid water intrusions were observed at the base of the halocline. On the temperature-salinity plots these stations indicate a mixing line that is different from the ambient water and seems to be conditioned by the ocean-glacier interaction. Our observations of Pacific water are set within the context of upstream observations in the Beaufort Sea and downstream observations from the Northeast Water Polynya, and clearly show the modification of Pacific water during its advection across the Arctic Ocean. Moreover, ambient water over the Wandel Sea slope shows different thermohaline structures indicating the different origin and pathways of the on-shore and off-shore branches of the Arctic Ocean outflow through the western Fram Strait.

The compositional change of Fluorescent Dissolved Organic Matter across Fram Strait assessed with use of a multi channel in situ fluorometer.

NASA Astrophysics Data System (ADS)

Raczkowska, A.; Kowalczuk, P.; Sagan, S.; Zabłocka, M.; Pavlov, A. K.; Granskog, M. A.; Stedmon, C. A.

2016-02-01

Observations of Colored Dissolved Organic Matter absorption (CDOM) and fluorescence (FDOM) from water samples and an in situ fluorometer and of Inherent Optical Properties (IOP; light absorption and scattering) were carried out along a section across Fram Strait at 79°N. A 3 channel Wetlabs Wetstar fluorometer was deployed, with channels for humic- and protein-like DOM and used to assess distribution of different FDOM fractions. A relationship between fluorescence intensity of the protein-like fraction of FDOM and chlorophyll a fluorescence was found and indicated the importance of phytoplankton biomass in West Spitsbergen Current waters as a significant source of protein-like FDOM. East Greenland Current waters has low concentration of chlorophyll a, and were characterized by high humic-like FDOM fluorescence. An empirical relationship between humic-like FDOM fluorescence intensity and CDOM absorption was derived and confirms the dominance of terrigenous like CDOM on the composition of DOM in the East Greenland Current. These high resolution profile data offer a simple approach to fractionate the contribution of these two DOM source to DOM across the Fram Strait and may help refine estimates of DOC fluxes in and out of the Arctic through this region.

Linkages between atmospheric blocking, sea ice export through Fram Strait and the Atlantic Meridional Overturning Circulation

PubMed Central

Ionita, M.; Scholz, P.; Lohmann, G.; Dima, M.; Prange, M.

2016-01-01

As a key persistent component of the atmospheric dynamics, the North Atlantic blocking activity has been linked to extreme climatic phenomena in the European sector. It has also been linked to Atlantic multidecadal ocean variability, but its potential links to rapid oceanic changes have not been investigated. Using a global ocean-sea ice model forced with atmospheric reanalysis data, here it is shown that the 1962–1966 period of enhanced blocking activity over Greenland resulted in anomalous sea ice accumulation in the Arctic and ended with a sea ice flush from the Arctic into the North Atlantic Ocean through Fram Strait. This event induced a significant decrease of Labrador Sea water surface salinity and an abrupt weakening of the Atlantic Meridional Overturning Circulation (AMOC) during the 1970s. These results have implications for the prediction of rapid AMOC changes and indicate that an important part of the atmosphere-ocean dynamics at mid- and high latitudes requires a proper representation of the Fram Strait sea ice transport and of the synoptic scale variability such as atmospheric blocking, which is a challenge for current coupled climate models. PMID:27619955

Linkages between atmospheric blocking, sea ice export through Fram Strait and the Atlantic Meridional Overturning Circulation.

PubMed

Ionita, M; Scholz, P; Lohmann, G; Dima, M; Prange, M

2016-09-13

As a key persistent component of the atmospheric dynamics, the North Atlantic blocking activity has been linked to extreme climatic phenomena in the European sector. It has also been linked to Atlantic multidecadal ocean variability, but its potential links to rapid oceanic changes have not been investigated. Using a global ocean-sea ice model forced with atmospheric reanalysis data, here it is shown that the 1962-1966 period of enhanced blocking activity over Greenland resulted in anomalous sea ice accumulation in the Arctic and ended with a sea ice flush from the Arctic into the North Atlantic Ocean through Fram Strait. This event induced a significant decrease of Labrador Sea water surface salinity and an abrupt weakening of the Atlantic Meridional Overturning Circulation (AMOC) during the 1970s. These results have implications for the prediction of rapid AMOC changes and indicate that an important part of the atmosphere-ocean dynamics at mid- and high latitudes requires a proper representation of the Fram Strait sea ice transport and of the synoptic scale variability such as atmospheric blocking, which is a challenge for current coupled climate models.

Impacts of extratropical storm tracks on Arctic sea ice export through Fram Strait

NASA Astrophysics Data System (ADS)

Wei, Jianfen; Zhang, Xiangdong; Wang, Zhaomin

2018-05-01

Studies have indicated regime shifts in atmospheric circulation, and associated changes in extratropical storm tracks and Arctic storm activity, in particular on the North Atlantic side of the Arctic Ocean. To improve understanding of changes in Arctic sea ice mass balance, we examined the impacts of the changed storm tracks and cyclone activity on Arctic sea ice export through Fram Strait by using a high resolution global ocean-sea ice model, MITgcm-ECCO2. The model was forced by the Japanese 25-year Reanalysis (JRA-25) dataset. The results show that storm-induced strong northerly wind stress can cause simultaneous response of daily sea ice export and, in turn, exert cumulative effects on interannual variability and long-term changes of sea ice export. Further analysis indicates that storm impact on sea ice export is spatially dependent. The storms occurring southeast of Fram Strait exhibit the largest impacts. The weakened intensity of winter (in this study winter is defined as October-March and summer as April-September) storms in this region after 1994/95 could be responsible for the decrease of total winter sea ice export during the same time period.

Atlantic water heat transfer through the Arctic Gateway (Fram Strait) during the Last Interglacial

NASA Astrophysics Data System (ADS)

Zhuravleva, Anastasia; Bauch, Henning A.; Spielhagen, Robert F.

2017-10-01

The Last Interglacial in the Arctic region is often described as a time with warmer conditions and significantly less summer sea ice than today. The role of Atlantic water (AW) as the main oceanic heat flux agent into the Arctic Ocean remains, however, unclear. Using high-resolution stable isotope and faunal records from the only deep Arctic Gateway, the Fram Strait, we note for the upper water column a diminished influence of AW and generally colder-than-Holocene surface ocean conditions. After the main Saalian deglaciation had terminated, a first intensification of northward-advected AW happened ( 124 ka). However, an intermittent sea surface cooling, triggered by meltwater release at 122 ka, caused a regional delay in the further development towards peak interglacial conditions. Maximum AW heat advection occurred during late MIS 5e (118.5-116 ka) and interrupted a longer-term cooling trend at the sea surface that started from about 120 ka on. Such a late occurrence of the major AW-derived near-surface warming in the Fram Strait - this is in stark contrast to an early warm peak in the Holocene - compares well in time with upstream records from the Norwegian Sea, altogether implying a coherent development of south-to-north ocean heat transfer through the eastern Nordic Seas and into the high Arctic during the Last Interglacial.

The freshwater export from the Arctic Ocean and the circulation of liquid freshwater around Greenland - constraints, interactions & consequences

NASA Astrophysics Data System (ADS)

Rudels, Bert

2010-05-01

The freshwater added to the Arctic Ocean is stored as sea ice and as liquid freshwater residing primarily in the upper layers. This allows for simple zero order estimates of the liquid freshwater content and export based on rotationally controlled baroclinic flow. At present the freshwater outflow occurs on both sides of Greenland. In Fram Strait the sea ice export in the East Greenland Current is significantly larger than the liquid freshwater outflow, while the liquid freshwater export dominates in the Canadian Arctic Archipelago. Although the outflow in the upper layer and the freshwater export respond to short periodic wind events and longer periodic atmospheric circulation patterns, the long-term trend is controlled by the net freshwater supply - the freshwater input minus the ice export. As the ice formation and ice export are expected to diminish in a warmer climate the Canadian Arctic Archipelago, comprising several passages, should gradually carry more of the total Arctic Ocean freshwater outflow. However, the channels in the Canadian Arctic Archipelago discharge into the restricted Baffin, which also receives a part of the Fram Strait freshwater export via the West Greenland Current. In a situation with increased glacial melting and freshwater discharge from Greenland the density of the upper layer in Baffin Bay may decrease considerably. This would reduce the sea level difference between the Arctic Ocean and Baffin Bay and thus weaken the outflow through the Canadian Arctic Archipelago, in extreme cases perhaps even reverse the flow. This would shift the main Arctic Ocean liquid freshwater export from The Canadian Arctic Archipelago to Fram Strait. The zero order dynamics of the exchanges through the Canadian Arctic Archipelago and Baffin Bay are described and the possibility for a weakening of the outflow is examined.

Remote sensing of the Fram Strait marginal ice zone

USGS Publications Warehouse

Shuchman, R.A.; Burns, B.A.; Johannessen, O.M.; Josberger, E.G.; Campbell, W.J.; Manley, T.O.; Lannelongue, N.

1987-01-01

Sequential remote sensing images of the Fram Strait marginal ice zone played a key role in elucidating the complex interactions of the atmosphere, ocean, and sea ice. Analysis of a subset of these images covering a 1-week period provided quantitative data on the mesoscale ice morphology, including ice edge positions, ice concentrations, floe size distribution, and ice kinematics. The analysis showed that, under light to moderate wind conditions, the morphology of the marginal ice zone reflects the underlying ocean circulation. High-resolution radar observations showed the location and size of ocean eddies near the ice edge. Ice kinematics from sequential radar images revealed an ocean eddy beneath the interior pack ice that was verified by in situ oceanographic measurements.

'Fram' in Color

NASA Technical Reports Server (NTRS)

2004-01-01

[figure removed for brevity, see original site] Click on the image for 'Fram' in Color (QTVR)

This view in approximately true color reveals details in an impact crater informally named 'Fram' in the Meridian Planum region of Mars. The picture is a mosaic of frames taken by the panoramic camera on NASA's Mars Exploration Rover Opportunity during the rover's 88th martian day on Mars, on April 23, 2004. The crater spans about 8 meters (26 feet) in diameter. Opportunity paused beside it while traveling from the rover's landing site toward a larger crater farther east. This view combines images taken using three of the camera's filters for different wavelengths of light: 750 nanometers, 530 nanometers and 430 nanometers.

Dissolved Organophosphate Esters and Polybrominated Diphenyl Ethers in Remote Marine Environments: Arctic Surface Water Distributions and Net Transport through Fram Strait.

PubMed

McDonough, Carrie A; De Silva, Amila O; Sun, Caoxin; Cabrerizo, Ana; Adelman, David; Soltwedel, Thomas; Bauerfeind, Eduard; Muir, Derek C G; Lohmann, Rainer

2018-06-05

Organophosphate esters (OPEs) have been found in remote environments at unexpectedly high concentrations, but very few measurements of OPE concentrations in seawater are available, and none are available in subsurface seawater. In this study, passive polyethylene samplers (PEs) deployed on deep-water moorings in the Fram Strait and in surface waters of Canadian Arctic lakes and coastal sites were analyzed for a suite of common OPEs. Total OPEs ( ∑ 11 OPE) at deep-water sites were dominated by chlorinated OPEs, and ranged from 6.3 to 440 pg/L. Concentrations were similar in eastern and western Fram Strait. Chlorinated OPEs were also dominant in Canadian Arctic surface waters (mean concentration ranged from < DL to 4400 pg/L), while nonhalogenated alkyl/aryl-substituted OPEs remained low (1.3-55 pg/L), possibly due to the greater long-range transport potential of chlorinated OPEs. Polybrominated diphenyl ethers (PBDEs) were found at much lower concentrations than OPEs (

Vertically Free-Standing Ordered Pb(Zr0.52Ti0.48)O3 Nanocup Arrays by Template-Assisted Ion Beam Etching

NASA Astrophysics Data System (ADS)

Zhang, Xiaoyan; Tang, Dan; Huang, Kangrong; Hu, Die; Zhang, Fengyuan; Gao, Xingsen; Lu, Xubing; Zhou, Guofu; Zhang, Zhang; Liu, Junming

2016-04-01

In this report, vertically free-standing lead zirconate titanate Pb(Zr0.52Ti0.48)O3 (PZT) nanocup arrays with good ordering and high density (1.3 × 1010 cm-2) were demonstrated. By a template-assisted ion beam etching (IBE) strategy, the PZT formed in the pore-through anodic aluminum oxide (AAO) membrane on the Pt/Si substrate was with a cup-like nanostructure. The mean diameter and height of the PZT nanocups (NCs) was about 80 and 100 nm, respectively, and the wall thickness of NCs was about 20 nm with a hole depth of about 80 nm. Uppermost, the nanocup structure with low aspect ratio realized vertically free-standing arrays when losing the mechanical support from templates, avoiding the collapse or bundling when compared to the typical nanotube arrays. X-ray diffraction (XRD) and Raman spectrum revealed that the as-prepared PZT NCs were in a perovskite phase. By the vertical piezoresponse force microscopy (VPFM) measurements, the vertically free-standing ordered ferroelectric PZT NCs showed well-defined ring-like piezoresponse phase and hysteresis loops, which indicated that the high-density PZT nanocup arrays could have potential applications in ultra-high non-volatile ferroelectric memories (NV-FRAM) or other nanoelectronic devices.

Fram Strait sea ice outflow

NASA Technical Reports Server (NTRS)

Kwok, R.; Cunningham, G. F.; Pang, S. S.

2004-01-01

We summarize 24 years of ice export estimates and examine, over a 9-year record, the associated variability in the time-varying upward-looking sonar (ULS) thickness distributions of the Fram Strait. A more thorough assessment of the PMW (passive microwave) ice motion with 5 years of synthetic aperture radar (SAR)observations shows the uncertainties to be consistent with that found by Kwok and Rothrock [1999], giving greater confidence to the record of ice flux calculations.

Models for Total-Dose Radiation Effects in Non-Volatile Memory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Campbell, Philip Montgomery; Wix, Steven D.

The objective of this work is to develop models to predict radiation effects in non- volatile memory: flash memory and ferroelectric RAM. In flash memory experiments have found that the internal high-voltage generators (charge pumps) are the most sensitive to radiation damage. Models are presented for radiation effects in charge pumps that demonstrate the experimental results. Floating gate models are developed for the memory cell in two types of flash memory devices by Intel and Samsung. These models utilize Fowler-Nordheim tunneling and hot electron injection to charge and erase the floating gate. Erase times are calculated from the models andmore » compared with experimental results for different radiation doses. FRAM is less sensitive to radiation than flash memory, but measurements show that above 100 Krad FRAM suffers from a large increase in leakage current. A model for this effect is developed which compares closely with the measurements.« less

Bathymetric patterns in standing stock and diversity of deep-sea nematodes at the long-term ecological research observatory HAUSGARTEN (Fram Strait)

NASA Astrophysics Data System (ADS)

Grzelak, Katarzyna; Kotwicki, Lech; Hasemann, Christiane; Soltwedel, Thomas

2017-08-01

Bathymetric patterns in standing stocks and diversity are a major topic of investigation in deep-sea biology. From the literature, responses of metazoan meiofauna and nematodes to bathymetric gradients are well studied, with a general decrease in biomass and abundance with increasing water depth, while bathymetric diversity gradients often, although it is not a rule, show a unimodal pattern. Spatial distribution patterns of nematode communities along bathymetric gradients are coupled with surface-water processes and interacting physical and biological factors within the benthic system. We studied the nematode communities at the Long-Term Ecological Research (LTER) observatory HAUSGARTEN, located in the Fram Strait at the Marginal Ice Zone, with respect to their standing stocks as well as structural and functional diversity. We evaluated whether nematode density, biomass and diversity indices, such as H0, Hinf, EG(50), Θ- 1, are linked with environmental conditions along a bathymetric transect spanning from 1200 m to 5500 m water depth. Nematode abundance, biomass and diversity, as well as food availability from phytodetritus sedimentation (indicated by chloroplastic pigments in the sediments), were higher at the stations located at upper bathyal depths (1200-2000 m) and tended to decrease with increasing water depth. A faunal shift was found below 3500 m water depth, where genus composition and trophic structure changed significantly and structural diversity indices markedly decreased. A strong dominance of very few genera and its high turnover particularly at the abyssal stations (4000-5500 m) suggests that environmental conditions were rather unfavorable for most genera. Despite the high concentrations of sediment-bound chloroplastic pigments and elevated standing stocks found at the deepest station (5500 m), nematode genus diversity remained the lowest compared to all other stations. This study provides a further insight into the knowledge of deep-sea nematodes, their diversity patterns and a deeper understanding of the environmental factors shaping nematodes communities at bathyal and abyssal depths.

TRISTEN/FRAM II Cruise Report, East Arctic, April 1980.

DTIC Science & Technology

1981-04-13

is not readily accessible by air from Alaska. The Eurasia Basin contains the Arctic Midoceanic Ridge, which extends in a straight line for 2000 km...13 6 Bottom Refraction - Shot- Lines Overlain on FRAM II Positions 14 7 Waterfall Display of Successive Spectral Estimates of Single...Northeast leg of the array was oriented 341T and the NW leg 304 ’T. After a windstorm and flow break-up on 16 April, hydrophones 11 and 12 and 21-24 were

­­­­Submarine Mass Wasting on Hovgaard Ridge, Fram Strait, European Arctic

NASA Astrophysics Data System (ADS)

Forwick, M.; Laberg, J. S.; Husum, K.; Gales, J. A.

2015-12-01

Hovgaard Ridge is an 1800 m high bathymetric high in the Fram Strait, the only deep-water gateway between the Arctic Ocean and the other World's oceans. The slopes of the ridge provide evidence of various types of sediment reworking, including 1) up to 12 km wide single and merged slide scars with maximum ~30 m high headwalls and some secondary escarpments; 2) maximum 3 km wide and 130 m deep slide scars with irregular internal morphology, partly narrowing towards the foot of the slope; 3) up to 130 m deep, 1.5 km wide and maximum 8 km long channels/gullies originating from areas of increasing slope angle at the margins of a plateau on top of the ridge. Most slide scars result presumably from retrogressive failure related to weak layers in contourites or ash. The most likely trigger mechanism is seismicity related to tectonic activity within the nearby mid-ocean fracture zone. Gully/channel formation is suggested to result from cascading water masses and/or from sediment gravity flows originating from failure at the slope break after winnowing on the plateau of the ridge.

Vertically Free-Standing Ordered Pb(Zr0.52Ti0.48)O3 Nanocup Arrays by Template-Assisted Ion Beam Etching.

PubMed

Zhang, Xiaoyan; Tang, Dan; Huang, Kangrong; Hu, Die; Zhang, Fengyuan; Gao, Xingsen; Lu, Xubing; Zhou, Guofu; Zhang, Zhang; Liu, Junming

2016-12-01

In this report, vertically free-standing lead zirconate titanate Pb(Zr0.52Ti0.48)O3 (PZT) nanocup arrays with good ordering and high density (1.3 × 10(10) cm(-2)) were demonstrated. By a template-assisted ion beam etching (IBE) strategy, the PZT formed in the pore-through anodic aluminum oxide (AAO) membrane on the Pt/Si substrate was with a cup-like nanostructure. The mean diameter and height of the PZT nanocups (NCs) was about 80 and 100 nm, respectively, and the wall thickness of NCs was about 20 nm with a hole depth of about 80 nm. Uppermost, the nanocup structure with low aspect ratio realized vertically free-standing arrays when losing the mechanical support from templates, avoiding the collapse or bundling when compared to the typical nanotube arrays. X-ray diffraction (XRD) and Raman spectrum revealed that the as-prepared PZT NCs were in a perovskite phase. By the vertical piezoresponse force microscopy (VPFM) measurements, the vertically free-standing ordered ferroelectric PZT NCs showed well-defined ring-like piezoresponse phase and hysteresis loops, which indicated that the high-density PZT nanocup arrays could have potential applications in ultra-high non-volatile ferroelectric memories (NV-FRAM) or other nanoelectronic devices.

Toward self-assembled ferroelectric random access memories: hard-wired switching capacitor arrays with almost Tb/in.(2) densities.

PubMed

Evans, Paul R; Zhu, Xinhau; Baxter, Paul; McMillen, Mark; McPhillips, John; Morrison, Finlay D; Scott, James F; Pollard, Robert J; Bowman, Robert M; Gregg, J Marty

2007-05-01

We report on the successful fabrication of arrays of switchable nanocapacitors made by harnessing the self-assembly of materials. The structures are composed of arrays of 20-40 nm diameter Pt nanowires, spaced 50-100 nm apart, electrodeposited through nanoporous alumina onto a thin film lower electrode on a silicon wafer. A thin film ferroelectric (both barium titanate (BTO) and lead zirconium titanate (PZT)) has been deposited on top of the nanowire array, followed by the deposition of thin film upper electrodes. The PZT nanocapacitors exhibit hysteresis loops with substantial remnant polarizations, while although the switching performance was inferior, the low-field characteristics of the BTO nanocapacitors show dielectric behavior comparable to conventional thin film heterostructures. While registration is not sufficient for commercial RAM production, this is nevertheless an embryonic form of the highest density hard-wired FRAM capacitor array reported to date and compares favorably with atomic force microscopy read-write densities.

FRAM-2012: Norwegians return to the High Arctic with a Hovercraft for Marine Geophysical Research

NASA Astrophysics Data System (ADS)

Hall, J. K.; Kristoffersen, Y.; Brekke, H.; Hope, G.

2012-12-01

After four years of testing methods, craft reliability, and innovative equipment, the R/H SABVABAA has embarked on its first FRAM-201x expedition to the highest Arctic. Named after the Inupiaq word for 'flows swiftly over it', the 12m by 6m hovercraft has been home-based in Longyearbyen, Svalbard since June 2008. In this, its fifth summer of work on the ice pack north of 81N, the craft is supported by the Norwegian Petroleum Directorate (NPD) via the Nansen Environmental and Remote Sensing Center (NERSC) in Bergen, and the Norwegian Scientific Academy for Polar Research. FRAM-2012 represents renewed Norwegian interest in returning to the highest Arctic some 116 years after the 1893-96 drift of Fridtjof Nansen's ship FRAM, the first serious scientific investigation of the Arctic. When replenished by air or icebreaker, the hovercraft Sabvabaa offers a hospitable scientific platform with crew of two, capable of marine geophysical, geological and oceanographic observations over long periods with relative mobility on the ice pack. FRAM-2012 is the first step towards this goal, accompanying the Swedish icebreaker ODEN to the Lomonosov Ridge, north of Greenland, as part of the LOMROG III expedition. The science plan called for an initial drive from the ice edge to Gakkel Ridge at 85N where micro-earthquakes would be monitored, and then to continue north to a geological sampling area on the Lomonosov Ridge at about 88N, 65W. The micro-earthquake monitoring is part of Gaute Hope's MSc thesis and entails five hydrophones in a WiFi-connected hydrophone array deployed over the Gakkel Rift Valley, drifting with the ice at up to 0.4 knots. On August 3 the hovercraft was refueled from icebreaker ODEN at 84-21'N and both vessels proceeded north. The progress of the hovercraft was hampered by insufficient visibility for safe driving and time consuming maneuvering in and around larger fields of rubble ice impassable by the hovercraft, but of little concern to the icebreaker. It became clear that to compensate for delayed rendezvous would take up substantially more icebreaker time than initially agreed to. It was therefore decided that the hovercraft would remain in the Gakkel Ridge survey area while the icebreaker would concentrate on its primary mission objective, a Danish UNCLOS survey. The two vessels would rejoin for the return journey to Svalbard in early September. The hovercraft has made continuous ice thickness measurements along its track by a front-mounted electromagnetic survey instrument in combination with a sonic height measuring device. The poster will present the findings of the expedition, and a short video is under preparation.

Enhanced energy harvesting in commercial ferroelectric materials

NASA Astrophysics Data System (ADS)

Patel, Satyanarayan; Chauhan, Aditya; Vaish, Rahul

2014-04-01

Ferroelectric materials are used in a number of applications ranging from simple sensors and actuators to ferroelectric random access memories (FRAMs), transducers, health monitoring system and microelectronics. The multiphysical coupling ability possessed by these materials has been established to be useful for energy harvesting applications. However, conventional energy harvesting techniques employing ferroelectric materials possess low energy density. This has prevented the successful commercialization of ferroelectric based energy harvesting systems. In this context, the present study aims at proposing a novel approach for enhanced energy harvesting using commercially available ferroelectric materials. This technique was simulated to be used for two commercially available piezoelectric materials namely PKI-552 and APCI-840, soft and hard lead-zirconate-titanate (PZT) pervoskite ceramics, respectively. It was observed that a maximum energy density of 348 kJm-3cycle-1 can be obtained for cycle parameters of (0-1 ton compressive stress and 1-25 kV.cm-1 electric field) using APCI-840. The reported energy density is several hundred times larger than the maximum energy density reported in the literature for vibration harvesting systems.

Fluorescent Random Amplified Microsatellites (F-RAMS) analysis of mushrooms as a forensic investigative tool.

PubMed

Kallifatidis, Beatrice; Borovička, Jan; Stránská, Jana; Drábek, Jiří; Mills, Deetta K

2014-03-01

The capability of Fluorescent Random Amplified Microsatellites (F-RAMS) to profile hallucinogenic mushrooms to species and sub-species level was assessed. Fifteen samples of Amanita rubescens and 22 samples of other hallucinogenic and non-hallucinogenic mushrooms of the genera Amanita and Psilocybe were profiled using two fluorescently-labeled, 5'degenerate primers, 5'-6FAM-SpC3-DD (CCA)5 and 5'-6FAM-SpC3-DHB (CGA)5, which target different microsatellite repeat regions. Among the two primers, 5'-6FAM-SpC3-DHB (CGA)5 provided more reliable data for identification purposes, by grouping samples of the same species and clustering closely related species together in a dendrogram based on amplicon similarities. A high degree of intra-specific variation between the 15 A. rubescens samples was shown with both primers and the amplicons generated for all A. rubescens samples were organized into three classes of amplicons (discriminant, private, and marker) based on their individualizing potential. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Nondestructive Analysis of MET-5 Paint Can at TA35 Building 2 A-Wing Vault

DOE Office of Scientific and Technical Information (OSTI.GOV)

Desimone, David J.; Vo, Duc Ta

In Building 2 A-wing vault MET-5 has some drums and other packages they wanted NEN-1 help identifying nondestructively. Measurements using a mechanically cooled portable high-purity germanium HPGe Ortec detective were taken of a paint can container labeled DU-2A to determine if any radioactive material was inside. The HPGe detector measures the gamma rays emitted by radioactive material and displays it as a spectrum. The spectrum is used to identify this radioactive material by using appropriate analysis software and identifying the gamma ray peaks. A paint can container, DU-2A, was analyzed with PeakEasy 4.84 and FRAM 5.2. The FRAM report ismore » shown. The enrichment is 0.091% U235 and 99.907% U238. This material is depleted uranium. The measurement was performed in the near field, and to extract a mass a far field measurement will need to be taken.« less

The large-scale freshwater cycle of the Arctic

NASA Astrophysics Data System (ADS)

Serreze, Mark C.; Barrett, Andrew P.; Slater, Andrew G.; Woodgate, Rebecca A.; Aagaard, Knut; Lammers, Richard B.; Steele, Michael; Moritz, Richard; Meredith, Michael; Lee, Craig M.

2006-11-01

This paper synthesizes our understanding of the Arctic's large-scale freshwater cycle. It combines terrestrial and oceanic observations with insights gained from the ERA-40 reanalysis and land surface and ice-ocean models. Annual mean freshwater input to the Arctic Ocean is dominated by river discharge (38%), inflow through Bering Strait (30%), and net precipitation (24%). Total freshwater export from the Arctic Ocean to the North Atlantic is dominated by transports through the Canadian Arctic Archipelago (35%) and via Fram Strait as liquid (26%) and sea ice (25%). All terms are computed relative to a reference salinity of 34.8. Compared to earlier estimates, our budget features larger import of freshwater through Bering Strait and larger liquid phase export through Fram Strait. While there is no reason to expect a steady state, error analysis indicates that the difference between annual mean oceanic inflows and outflows (˜8% of the total inflow) is indistinguishable from zero. Freshwater in the Arctic Ocean has a mean residence time of about a decade. This is understood in that annual freshwater input, while large (˜8500 km3), is an order of magnitude smaller than oceanic freshwater storage of ˜84,000 km3. Freshwater in the atmosphere, as water vapor, has a residence time of about a week. Seasonality in Arctic Ocean freshwater storage is nevertheless highly uncertain, reflecting both sparse hydrographic data and insufficient information on sea ice volume. Uncertainties mask seasonal storage changes forced by freshwater fluxes. Of flux terms with sufficient data for analysis, Fram Strait ice outflow shows the largest interannual variability.

Clinical Investigation Program Annual Progress Report.

DTIC Science & Technology

1984-09-30

145 80/201 Camparison of Cardiac Output and Left Ventricular Stroke Work Before and After Standard Anesthesia Induction of Patients Unrergoing...Role of Minimal Surgical Debridement in the Treatment of Vesicant Extravasations. (O)(PR) ....... 159 84/200 Prevention of Macular Injury frm High...fram or Help Prevent Bone Injury .(C)(P)(PR) .................... 171 80/302 Rapid Detection of Bacterial Antigens in Patient Specimens Using

Spatial and temporal scales of sea ice protists and phytoplankton distribution from the gateway Fram Strait into the Central Arctic Ocean

NASA Astrophysics Data System (ADS)

Peeken, I.; Hardge, K.; Krumpen, T.; Metfies, K.; Nöthig, E. M.; Rabe, B.; von Appen, W. J.; Vernet, M.

2016-02-01

The Arctic Ocean is currently one of the key regions where the effect of climate change is most pronounced. Sea ice is an important interface in this region by representing a unique habitat for many organisms. Massive reduction of sea ice thickness and extent, which have been recorded over the last twenty years, is anticipated to cause large cascading changes in the entire Arctic ecosystem. Most sea ice is formed on the Eurasian shelves and transported via the Transpolardrift to the western Fram Strait and out of the Arctic Ocean with the cold East Greenland Current (EGC). Warm Atlantic water enters the Arctic Ocean with the West Spitsbergen Current (WSC) via eastern Fram Strait. Here, we focus on the spatial spreading of protists from the Atlantic water masses, and their occurrences over the deep basins of the Central Arctic and the relationship amongst them in water and sea ice. Communities were analyzed by using pigments, flow cytometer and ARISA fingerprints during several cruises with the RV Polarstern to the Fram Strait, the Greenland Sea and the Central Arctic Ocean. By comparing these data sets we are able to demonstrate that the origin of the studied sea ice floes is more important for the biodiversity found in the sea ice communities then the respective underlying water mass. In contrast, biodiversity in the water column is mainly governed by the occurring water masses and the presence or absence of sea ice. However, overall the development of standing stocks in both biomes was governed by the availability of nutrients. To get a temporal perspective of the recent results, the study will be embedded in a long-term data set of phytoplankton biomass obtained during several cruises over the last twenty years.

Current Pattern Change in the Fram Strait at the Pliocene/Pleistocene Boundary

NASA Astrophysics Data System (ADS)

Gebhardt, C.; Geissler, W. H.; Matthiessen, J. J.; Jokat, W.

2014-12-01

Thick packages of drift-type sediments were identified in the northwestern and central part of the Fram Strait, mainly along the western Yermak Plateau flank, but also in the central, flat part of the Fram Strait. A large-scale field of sediment waves was found north of 80.5°, along the Yermak Plateau rise. This field separates two drift bodies, a deeper one towards west and a shallower one towards east. The drift bodies were deposited by bottom currents, most likely by the northbound Yermak Branch of the West Spitsbergen Current, but an influence of a southbound current on the westren drift body cannot be ruled out. Within the drift bodies and even more pronounced withing the sediment waves, a stratigraphic boundary is clearly visible. It separates a lower package of waves migrating upslope at a low angle of ~5° from an upper package with significantly increased wave crest migration at ~16.5°. Using the seismic network, this stratigraphic boundary could be tracked to ODP Leg 151, Site 911, where it corresponds to the lithostratigraphic boundary between units IA and IB dated to 2.7 Ma. The increase in wave-crest migration angle points at a shift towards higher sedimentation rates at 2.7 Ma. This corresponds to the intensification of the Northern Hemisphere glaciation with a major expansion of the Scandinavian, northern Barents Sea, North American and Greenland ice sheets. The Barents Shelf that was subaerially exposed and the expansion of the northern Barents Sea ice sheet (as well as Svalbard) are the likely sources for enhanced erosion and fluvial input along the pathway of the West Spitsbergen Current, resulting in higher sedimentation rates in the Fram Strait.

Biogeographic patterns of bacterial microdiversity in Arctic deep-sea sediments (HAUSGARTEN, Fram Strait)

PubMed Central

Buttigieg, Pier Luigi; Ramette, Alban

2015-01-01

Marine bacteria colonizing deep-sea sediments beneath the Arctic ocean, a rapidly changing ecosystem, have been shown to exhibit significant biogeographic patterns along transects spanning tens of kilometers and across water depths of several thousand meters (Jacob et al., 2013). Jacob et al. (2013) adopted what has become a classical view of microbial diversity – based on operational taxonomic units clustered at the 97% sequence identity level of the 16S rRNA gene – and observed a very large microbial community replacement at the HAUSGARTEN Long Term Ecological Research station (Eastern Fram Strait). Here, we revisited these data using the oligotyping approach and aimed to obtain new insight into ecological and biogeographic patterns associated with bacterial microdiversity in marine sediments. We also assessed the level of concordance of these insights with previously obtained results. Variation in oligotype dispersal range, relative abundance, co-occurrence, and taxonomic identity were related to environmental parameters such as water depth, biomass, and sedimentary pigment concentration. This study assesses ecological implications of the new microdiversity-based technique using a well-characterized dataset of high relevance for global change biology. PMID:25601856

Ice-tethered measurement platforms in the Arctic Ocean: a contribution by the FRAM infrastructure program

NASA Astrophysics Data System (ADS)

Hoppmann, Mario; Nicolaus, Marcel; Rabe, Benjamin; Wenzhöfer, Frank; Katlein, Christian; Scholz, Daniel

2016-04-01

The Arctic Ocean has been in the focus of many studies during recent years, investigating the state, the causes and the implications of the observed rapid transition towards a thinner and younger sea-ice cover. However, consistent observational datasets of sea ice, ocean and atmosphere are still sparse due to the limited accessibility and harsh environmental conditions. One important tool to fill this gap has become more and more feasible during recent years: autonomous, ice-tethered measurement platforms (buoys). These drifting instruments independently transmit their data via satellites, and enable observations over larger areas and over longer time periods than manned expeditions, even throughout the winter. One aim of the newly established FRAM (FRontiers in Arctic marine Monitoring) infrastructure program at the Alfred-Wegener-Institute is to realize and maintain an interdisciplinary network of buoys in the Arctic Ocean, contributing to an integrated, Arctic-wide observatory. The additional buoy infrastructure, ship-time, and developments provided by FRAM are critical elements in the ongoing international effort to fill the large data gaps in a rapidly changing Arctic Ocean. Our focus is the particularly underrepresented Eurasian Basin. Types of instruments range from snow depth beacons and ice mass balance buoys for monitoring ice growth and snow accumulation, over radiation and weather stations for energy budget estimates, to ice-tethered profiling systems for upper ocean monitoring. Further, development of new bio-optical and biogeochemical buoys is expected to enhance our understanding of bio-physical processes associated with Arctic sea ice. The first set of FRAM buoys was deployed in September 2015 from RV Polarstern. All datasets are publicly available on dedicated web portals. Near real time data are reported into international initiatives, such as the Global Telecommunication System (GTS) and the International Arctic Buoy Programme (IABP). The additional data acquired by FRAM buoys facilitate the validation of model results and remote sensing products, play an important role in understanding the linkages between the atmosphere, sea ice and upper ocean, and help assess the physical, biological and biogeochemical states of the future Arctic Ocean. Here we present our recent work and future plans, but are also aiming for additional collaborations, especially on technical developments, scientific questions and deployment logistics.

Performance Enhancement Of A Low Cost Multimode Fiber Optic Rotation Sensor

NASA Astrophysics Data System (ADS)

Fredricks, Ronald J.; Johnson, Dean R.

1989-02-01

Several fiber optic Sagnac interferometers employing multimode fiber of both high and ffedimiNrrumbers and simple LED light sources, have been designed and built by the authors over the past two years. New results showing improved performance fran that reported at the August '87 SPIE are given in this paper. The ratios of maximum unambiguous rate signal to random 3a drift signal are now in the range 50-150 a performance enhancement of between 4 and 10. We have found that a step index ring rather than a grajled Index one is necess for good driftperformance and that best results are obtained when all the other ring elements (PZT coary il and I/O slitter are also fabricated fram step index fiber. The 3a drifts in our 200 meter 10 cm diameter breadboards, in particular, are around 1°/sec. Using high V number fiber (100 pm/0.29 NA) no static mode mixers are required to desensitize this relatively short sense coil fram environmental pertubations. With unambiguous maxi rum rates on the order of ±200°/sec using simple detection of the MT fundamental signal the performance of these breadboard systems is now as good or better than many law cost "Coriolis" type rate sensors on the market.

Arctic sea ice thickness characteristics in winter 2004 and 2007 from submarine sonar transects

NASA Astrophysics Data System (ADS)

Wadhams, Peter; Hughes, Nick; Rodrigues, JoãO.

2011-08-01

A transect of the Arctic Ocean by the British submarine Tireless in March 2007 enabled the thickness characteristics of the ice cover to be measured during the winter immediately preceding the exceptional retreat of summer 2007. In this paper we report on mean and modal drafts, probability density functions of draft, and the frequency and depth distribution of pressure ridges, and we compare results with those from an earlier submarine cruise in winter 2004 which covered part of the same area. In the region from north of Fram Strait to Ellesmere Island (about 85°N, 0-70°W) we find no change in mean drafts between 2004 and 2007 though there is a change in ice composition, with more ridging in 2007 but a lesser modal draft. This agrees with the observations of younger ice being driven toward Fram Strait in 2007. The region north of Ellesmere Island continues to be a "redoubt" containing more thick deformed multiyear ice than any other part of the transect. In the west the submarine profiled extensively under the SEDNA ice camp at 73°N 145°W. This is in the same location as the 1976 AIDJEX ice camp and a sonar survey done by a U.S. submarine in April 1976. We found that a large decrease in mean draft had occurred (32%) over 31 years and that in 2007 the SEDNA region contained the thinnest ice of any part of the Arctic surveyed by the submarine; this was a region from which the ice completely retreated during the subsequent summer of 2007.

30 years of Arctic sea ice thickness measurements by Royal Navy submarines

NASA Astrophysics Data System (ADS)

Wadhams, P.; Hughes, N.; Rodrigues, J. M.; Toberg, N.

2009-12-01

Royal Navy submarines fitted with upward-looking sonars have been collecting sea ice thickness data in the Arctic Ocean since the early 1970s. These data sets provide unique information on the Arctic sea ice thickness distribution and the way it has been changing in the past decades. In March 2007 HMS Tireless conducted a transect of the Arctic Ocean from Fram Strait to the western Beaufort Sea which gave the opportunity to measure the thickness of the sea ice cover during the winter immediately preceding the exceptional retreat of summer 2007. Three years earlier, in April 2004, a voyage by the same submarine took sea ice thickness data in the regions of Fram Strait, the Lincoln Sea and the North Pole. We report on the ice draft, pressure ridge and lead distributions obtained in these two cruises and analyse the evolution of the ice cover from 2004 to 2007 in areas of coincident tracks. In the region from north of Fram Strait to Ellesmere Island (about 85°N, 0-70°W) we find no change in mean drafts between 2004 and 2007 although there is a change in ice composition, with more ridging in 2007 and a slight reduction of modal draft. This agrees with the concept of young ice being driven towards Fram Strait. The region north of Ellesmere Island continues to be a "redoubt" of very thick deformed multiyear ice. In 2007 the submarine profiled extensively under the DAMOCLES ice camp at about 85°N 64°W and under the SEDNA ice camp at about 73°N 145°W. The latter is in the same location as the 1976 AIDJEX ice camp and a sonar survey done by a US submarine in April 1976. We found that a large decrease in mean draft had occurred (32%) over 31 years and that in 2007 the SEDNA region contained the thinnest ice of any part of the Arctic surveyed by the submarine. Under the DAMOCLES ice camp about 200km of topographic sea ice data were gathered with a Kongsberg EM3002 multibeam (MB) sonar, making this the largest continuous data set of its kind. The MB data produce high resolution three-dimensional images of the sea ice underside allowing for rapid demarcation of first and multi-year ice regimes along with pressure ridge classification and orientation. In order to estimate the rate of thinning of the Arctic sea ice we compare the ice thickness distributions of 2004 and 2007 with those derived from similar types of sonars that have been fitted to UK submarines on cruises since 1976. Of these, ice draft data obtained during a cruise in April 1991, and re-processing to the same standard as 2004 and 2007, has special significance because of the vast amount of data collected in Fram Strait, on the way to the Pole along the prime meridian and a survey of a region of the Arctic Ocean north of Svalbard and Franz Joseph Land.

Using fluorescent dissolved organic matter to trace and distinguish the origin of Arctic surface waters

PubMed Central

Gonçalves-Araujo, Rafael; Granskog, Mats A.; Bracher, Astrid; Azetsu-Scott, Kumiko; Dodd, Paul A.; Stedmon, Colin A.

2016-01-01

Climate change affects the Arctic with regards to permafrost thaw, sea-ice melt, alterations to the freshwater budget and increased export of terrestrial material to the Arctic Ocean. The Fram and Davis Straits represent the major gateways connecting the Arctic and Atlantic. Oceanographic surveys were performed in the Fram and Davis Straits, and on the east Greenland Shelf (EGS), in late summer 2012/2013. Meteoric (fmw), sea-ice melt, Atlantic and Pacific water fractions were determined and the fluorescence properties of dissolved organic matter (FDOM) were characterized. In Fram Strait and EGS, a robust correlation between visible wavelength fluorescence and fmw was apparent, suggesting it as a reliable tracer of polar waters. However, a pattern was observed which linked the organic matter characteristics to the origin of polar waters. At depth in Davis Strait, visible wavelength FDOM was correlated to apparent oxygen utilization (AOU) and traced deep-water DOM turnover. In surface waters FDOM characteristics could distinguish between surface waters from eastern (Atlantic + modified polar waters) and western (Canada-basin polar waters) Arctic sectors. The findings highlight the potential of designing in situ multi-channel DOM fluorometers to trace the freshwater origins and decipher water mass mixing dynamics in the region without laborious samples analyses. PMID:27667721

Fabrication and characterization of lead-free BaTiO3 thin film for storage device applications

NASA Astrophysics Data System (ADS)

Sharma, Hakikat; Negi, N. S.

2018-05-01

The lead-free BaTiO3 (BT) thin film solution has been prepared by sol-gel method. The prepared solution spin coated on Pt/TiO2/SiO2/ Si substrate. The fabricated thin film was analyzed by XRD and Raman spectrometer for structural conformation. Uniformity of thin film was examined by Atomic force microscope (AFM). Thickness of the film was measured by cross sectional FESEM. Activation energies for both positive and negative biasing have been calculated from temperature dependent leakage current density as a function of electric field. For ferroelectric memory devices such as FRAM the hysteresis loop plays important role. Electric filed dependent polarization of BT thin film measured at different switching voltages. With increasing voltage maximum polarization increases.

Development and characterization of a ferroelectric non-volatile memory for flexible electronics

NASA Astrophysics Data System (ADS)

Mao, Duo

Flexible electronics have received significant attention recently because of the potential applications in displays, sensors, radio frequency identification (RFID) tags and other integrated circuits. Electrically addressable non-volatile memory is a key component for these applications. The major challenges are to fabricate the memory at a low temperature compatible with plastic substrates while maintaining good device reliability, by being compatible with process as needed to integrate with other electronic components for system-on-chip applications. In this work, ferroelectric capacitors fabricated at low temperature were developed. Based on that, a ferroelectric random access memory (FRAM) for flexible electronics was developed and characterized. Poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] copolymer was used as a ferroelectric material and a photolithographic process was developed to fabricate ferroelectric capacitors. Different characterization methods including atomic force microscopy, x-ray diffraction and Fourier-transform infrared reflection-absorption spectroscopy were used to study the material properties of the P(VDF-TrFE) film. The material properties were correlated with the electrical characteristics of the ferroelectric capacitors. To understand the polarization switching behavior of the P(VDF-TrFE) ferroelectric capacitors, a Nucleation-Limited-Switching (NLS) model was used to study the switching kinetics. The switching kinetics were characterized over the temperature range from -60 °C to 100 °C. Fatigue characteristics were studied at different electrical stress voltages and frequencies to evaluate the reliability of the ferroelectric capacitor. The degradation mechanism is attributed to the increase of the activation field and the suppression of the switchable polarization. To develop a FRAM circuit for flexible electronics, an n-channel thin film transistor (TFT) based on CdS as the semiconductor was integrated with a P(VDF-TrFE) ferroelectric capacitor for a one-transistor-one-capacitor (1T1C) memory cell. The 1T1C devices were fabricated at low temperature and demonstrated a memory window (DeltaVBL) of 2.3 V and 3.5 V, depending on the device dimensions. Next, FRAM arrays (4-bit, 16-bit and 64-bit) based on the two-transistor-two-capacitor (2T2C) memory cell architecture were designed and fabricated using a photolithographic process with 9 masks. The fabricated FRAM arrays were packaged in 28-pin ceramic packages. The read/write schemes were developed and the FRAM arrays show successful program and erase with a memory window of approximately 1 V at the output of the sense amplifier.

Arctic sea ice variability during the last deglaciation: a biomarker approach

NASA Astrophysics Data System (ADS)

Müller, J.; Stein, R. H.

2014-12-01

The last transition from full glacial to current interglacial conditions was accompanied by distinct short-term climate fluctuations caused by changes in the global ocean circulation system. Most palaeoceanographic studies focus on the documentation of the behaviour of the Atlantic Meridional Overturning Circulation (AMOC) during the last deglaciation in response to freshwater forcing events. In this respect, the role of Arctic sea ice remained relatively unconsidered - primarily because of the difficulty of its reconstruction. Here we present new proxy data on late glacial (including the Last Glacial Maximum; LGM) and deglacial sea ice variability in the Arctic Ocean and its main gateway - the Fram Strait - and how these changes in sea ice coverage contributed to AMOC perturbations observed during Heinrich Event 1 and the Younger Dryas. Recurrent short-term advances and retreats of sea ice in Fram Strait, prior and during the LGM, are in line with a variable (or intermittent) North Atlantic heat flow along the eastern corridor of the Nordic Seas. Possibly in direct response to the initial freshwater discharge from melting continental ice-sheets, a permanent sea ice cover established only at about 19 ka BP (i.e. post-LGM) and lasted until 17.6 ka BP, when an abrupt break-up of this thick ice cover and a sudden discharge of huge amounts of sea ice and icebergs through Fram Strait coincided with the weakening of the AMOC during Heinrich Event 1. Similarly, another sea ice maximum at about 12.8 ka BP is associated with the slowdown of the AMOC during the Younger Dryas. The new data sets clearly highlight the important role of Arctic sea ice for the re-organisation of the oceanographic setting in the North Atlantic during the last deglaciation. Further studies and sensitivity experiments to identify crucial driving (and feedback) mechanisms within the High Latitude ice-ocean-atmosphere system will contribute the understanding of rapid climate changes.

A comparison of radiation budgets in the Fram Strait marginal ice zone

NASA Technical Reports Server (NTRS)

Francis, Jennifer A.; Katsaros, Kristina B.; Ackerman, Thomas P.; Lind, Richard J.; Davidson, Kenneth L.

1991-01-01

Results are presented from calculations of radiation budgets for the sea-ice and the open-water regimes in the marginal ice zone (MIZ) of the Fram Strait, from measurements of surface irradiances and meteorological conditions made during the 1984 Marginal Ice Zone Experiment. Simultaneous measurements on either side of the ice edge allowed a comparison of the open-water and the sea-ice environments. The results show significant differences between the radiation budgets of the two regimes in the MIZ. The open water absorbed twice as much radiation as did the ice, and the mean cooling rate of the atmosphere over water was approximately 15 percent larger than that over ice. Calculated fluxes and atmospheric cooling rates were found to compare well with available literature data.

Variability in pteropod sedimentation and corresponding aragonite flux at the Arctic deep-sea long-term observatory HAUSGARTEN in the eastern Fram Strait from 2000 to 2009

NASA Astrophysics Data System (ADS)

Bauerfeind, E.; Nöthig, E.-M.; Pauls, B.; Kraft, A.; Beszczynska-Möller, A.

2014-04-01

Pteropods are an important component of the zooplankton community and hence of the food web in the Fram Strait. They have a calcareous (aragonite) shell and are thus sensitive in particular to the effects of the increasing CO2 concentration in the atmosphere and the associated changes of pH and temperature in the ocean. In the eastern Fram Strait, two species of thecosome pteropods occur, the cold water-adapted Limacina helicina and the subarctic boreal species Limacina retroversa. Both species were regularly observed in year-round moored sediment traps at ~ 200-300 m depth in the deep-sea long-term observatory HAUSGARTEN (79°N, 4°E). The flux of all pteropods found in the trap samples varied from < 20 to ~ 870 specimen m- 2 d- 1 in the years 2000-2009, being lower during the period 2000-2006. At the beginning of the time series, pteropods were dominated by the cold-water-adapted L. helicina, whereas the subarctic boreal L. retroversa was only occasionally found in large quantities (> 50 m- 2 d- 1). This picture completely changed after 2005/6 when L. retroversa became dominant and total pteropod numbers in the trap samples increased significantly. Concomitant to this shift in species composition, a warming event occurred in 2005/6 and persisted until the end of the study in 2009, despite a slight cooling in the upper water layer after 2007/8. Sedimentation of pteropods showed a strong seasonality, with elevated fluxes of L. helicina from August to November. Numbers of L. retroversa usually increased later, during September/October, with a maximum at the end of the season during December/January. In terms of carbonate export, aragonite shells of pteropods contributed with 11-77% to the annual total CaCO3 flux in Fram Strait. The highest share was found in the period 2007 to 2009, predominantly during sedimentation events at the end of the year. Results obtained by sediment traps occasionally installed on a benthic lander revealed that pteropods also arrive at the seafloor (~ 2550 m) almost simultaneous with their occurrence in the shallower traps. This indicates a rapid downward transport of calcareous shells, which provides food particles for the deep-sea benthos during winter when other production in the upper water column is shut down. The results of our study highlight the great importance of pteropods for the biological carbon pump as well as for the carbonate system in Fram Strait at present, and indicate modifications within the zooplankton community. The results further emphasize the importance of long-term investigation to disclose such changes.

Demographic patterns of postfire regeneration in mediterranean-climate shrublands of California

USGS Publications Warehouse

Keeley, J.E.; Fotheringham, C.J.; Baer-Keeley, M.

2006-01-01

Eggs of captive black ducks fed diets containing DDE at 10 and 30 ppm (dry weight) experienced significant shell thinning and an increase in shell cracking when compared to eggs of untreated black ducks. Eggshells from dosed ducks were: 18-24 percent thinner at the equator than shells from undosed ducks; 28-31 percent thinner at the cap; and 29-38 percent thinner at the apex. Shell cracking averaged 21 percent among eggs fram the 30 ppm DDE dosage and 10 percent among eggs from the 10 ppm dosage. Only 2 percent of the eggs from untreated black ducks were cracked. Survival of ducklings fram dosed parents in terms of 'percentage of 21-day ducklings of embryonated eggs' was 40-76 percent lower than survival of ducklings from undosed parents. Average DDE residues (wet weight) in eggs from hens fed 10 and 30 ppm DDE were 46 ppm and 144 ppm, respectively.

Ice Sheet and Sea Ice Observations from Unmanned Aircraft Systems

NASA Astrophysics Data System (ADS)

Crocker, R. I.; Maslanik, J. A.

2011-12-01

A suite of sensors has been assembled to map ice sheet and sea ice surface topography with fine-resolution from small unmanned aircraft systems (UAS). This payload is optimized to provide coincident surface elevation and imagery data, and with its low cost and ease of reproduction, it has the potential to become a widely-distributed observational resource to complement polar manned-aircraft and satellite missions. To date, it has been deployed to map ice sheet elevations near Jakobshavn Isbræ in Greenland, and to measure sea ice freeboard and roughness in Fram Strait off the coast of Svalbard. Data collected during these campaigns have facilitate a detailed assessment of the system's surface elevation measurement accuracy, and provide a glimpse of the summer 2009 Fram Strait sea ice conditions. These findings are presented, along with a brief overview of our future Arctic UAS operations.

Sea ice studies in the Spitsbergen-Greenland area

NASA Technical Reports Server (NTRS)

Vinje, T. E. (Principal Investigator)

1976-01-01

The author has identified the following significant results. Data showed unexpected great variations in the drift velocity of the ice in the Fram Strait. Land map improvements were achieved by LANDSAT in the eastern part of the Svalbard archipelago.

Arctic Deep Water Ferromanganese-Oxide Deposits Reflect the Unique Characteristics of the Arctic Ocean

NASA Astrophysics Data System (ADS)

Hein, James R.; Konstantinova, Natalia; Mikesell, Mariah; Mizell, Kira; Fitzsimmons, Jessica N.; Lam, Phoebe J.; Jensen, Laramie T.; Xiang, Yang; Gartman, Amy; Cherkashov, Georgy; Hutchinson, Deborah R.; Till, Claire P.

2017-11-01

Little is known about marine mineral deposits in the Arctic Ocean, an ocean dominated by continental shelf and basins semi-closed to deep-water circulation. Here, we present data for ferromanganese crusts and nodules collected from the Amerasia Arctic Ocean in 2008, 2009, and 2012 (HLY0805, HLY0905, and HLY1202). We determined mineral and chemical compositions of the crusts and nodules and the onset of their formation. Water column samples from the GEOTRACES program were analyzed for dissolved and particulate scandium concentrations, an element uniquely enriched in these deposits. The Arctic crusts and nodules are characterized by unique mineral and chemical compositions with atypically high growth rates, detrital contents, Fe/Mn ratios, and low Si/Al ratios, compared to deposits found elsewhere. High detritus reflects erosion of submarine outcrops and North America and Siberia cratons, transport by rivers and glaciers to the sea, and distribution by sea ice, brines, and currents. Uniquely high Fe/Mn ratios are attributed to expansive continental shelves, where diagenetic cycling releases Fe to bottom waters, and density flows transport shelf bottom water to the open Arctic Ocean. Low Mn contents reflect the lack of a mid-water oxygen minimum zone that would act as a reservoir for dissolved Mn. The potential host phases and sources for elements with uniquely high contents are discussed with an emphasis on scandium. Scandium sorption onto Fe oxyhydroxides and Sc-rich detritus account for atypically high scandium contents. The opening of Fram Strait in the Miocene and ventilation of the deep basins initiated Fe-Mn crust growth ˜15 Myr ago.

Arctic deep-water ferromanganese-oxide deposits reflect the unique characteristics of the Arctic Ocean

USGS Publications Warehouse

Hein, James; Konstantinova, Natalia; Mikesell, Mariah; Mizell, Kira; Fitzsimmons, Jessica N.; Lam, Phoebe; Jensen, Laramie T.; Xiang, Yang; Gartman, Amy; Cherkashov, Georgy; Hutchinson, Deborah; Till, Claire P.

2017-01-01

Little is known about marine mineral deposits in the Arctic Ocean, an ocean dominated by continental shelf and basins semi-closed to deep-water circulation. Here, we present data for ferromanganese crusts and nodules collected from the Amerasia Arctic Ocean in 2008, 2009, and 2012 (HLY0805, HLY0905, HLY1202). We determined mineral and chemical compositions of the crusts and nodules and the onset of their formation. Water column samples from the GEOTRACES program were analyzed for dissolved and particulate scandium concentrations, an element uniquely enriched in these deposits.The Arctic crusts and nodules are characterized by unique mineral and chemical compositions with atypically high growth rates, detrital contents, Fe/Mn ratios, and low Si/Al ratios, compared to deposits found elsewhere. High detritus reflects erosion of submarine outcrops and North America and Siberia cratons, transport by rivers and glaciers to the sea, and distribution by sea ice, brines, and currents. Uniquely high Fe/Mn ratios are attributed to expansive continental shelves, where diagenetic cycling releases Fe to bottom waters, and density flows transport shelf bottom water to the open Arctic Ocean. Low Mn contents reflect the lack of a mid-water oxygen minimum zone that would act as a reservoir for dissolved Mn. The potential host phases and sources for elements with uniquely high contents are discussed with an emphasis on scandium. Scandium sorption onto Fe oxyhydroxides and Sc-rich detritus account for atypically high scandium contents. The opening of Fram Strait in the Miocene and ventilation of the deep basins initiated Fe-Mn crust growth ∼15 Myr ago.

A MODELLING FRAMEWORK FOR MERCURY CYCLING IN LAKE MICHIGAN

EPA Science Inventory

A time-dependent mercury model was developed to describe mercury cycling in Lake Michigan. The model addresses dynamic relationships between net mercury loadings and the resulting concentrations of mercury species in the water and sediment. The simplified predictive modeling fram...

MEMS-based flexible reflective analog modulators (FRAM) for projection displays: a technology review and scale-down study

NASA Astrophysics Data System (ADS)

Picard, Francis; Ilias, Samir; Asselin, Daniel; Boucher, Marc-André; Duchesne, François; Jacob, Michel; Larouche, Carl; Vachon, Carl; Niall, Keith K.; Jerominek, Hubert

2011-02-01

A MEMS based technology for projection display is reviewed. This technology relies on mechanically flexible and reflective microbridges made of aluminum alloy. A linear array of such micromirrors is combined with illumination and Schlieren optics to produce a pixels line. Each microbridge in the array is individually controlled using electrostatic actuation to adjust the pixels intensities. Results of the simulation, fabrication and characterization of these microdevices are presented. Activation voltages below 250 V with response times below 10 μs were obtained for 25 μm × 25 μm micromirrors. With appropriate actuation voltage waveforms, response times of 5 μs and less are achievable. A damage threshold of the mirrors above 8 kW/cm2 has been evaluated. Development of the technology has produced projector engines demonstrating this light modulation principle. The most recent of these engines is DVI compatible and displays VGA video streams at 60 Hz. Recently applications have emerged that impose more stringent requirements on the dimensions of the MEMS array and associated optical system. This triggered a scale down study to evaluate the minimum micromirror size achievable, the impact of this reduced size on the damage threshold and the achievable minimum size of the associated optical system. Preliminary results of this scale down study are reported. FRAM with active surface as small as 5 μm × 5 μm have been investigated. Simulations have shown that such micromirrors could be activated with 107 V to achieve f-number of 1.25. The damage threshold has been estimated for various FRAM sizes. Finally, design of a conceptual miniaturized projector based on 1000×1 array of 5 μm × 5 μm micromirrors is presented. The volume of this projector concept is about 12 cm3.

Fram Strait: Atmospheric Forcing of The Sea Ice Flux

NASA Astrophysics Data System (ADS)

Widell, K.; Østerhus, S.; Gammelsrød, T.

Measuring the magnitude and variability of the ice and freshwater flux through Fram Strait is an important element in understanding climate variability in the Arctic. Since the major part of the ice and freshwater that leaves the Arctic passes through Fram Strait, this passage can be considered a key area for estimating the net ice production in the Arctic Ocean. In 1990, the Norwegian Polar Institute (NPI) started a monitoring program in the strait, most years by means of two moorings with Upward Looking Sonars (ULS) measuring ice draft. From 1995 and on, these moorings were also equipped with Doppler Current Meters (DCM) to measure the ice velocity. These measurements give an opportunity to investigate the different forces affecting ice motion in the strait. Maximum correlation coefficient between atmospheric sea level pressure (from NCEP/NCAR reanalysed data) and southward ice velocity is found when using the cross strait pressure difference along 80N between 10W and 5E (R = 0.72) consider- ing monthly means. Subtracting current velocity at 50 m depth (also measured by the DCM) from ice velocity improves the correlation to R = 0.84. This gives insight in the relative importance of current and wind on the ice motion, and indicates that pressure data can be used to make fairly good estimates of the ice velocity in the strait. In combination with data on ice thickness and ice stream width, this result is used to calculate the ice volume transport. By making assumptions on the parameters in- volved, the time series is extended back to 1948, the start of the pressure record. This time series will be presented and compared to literature, and annual and seasonal vari- ation of the ice flux will be discussed.

Deep ocean ventilation in the Central Fram Strait during the past 35 kyr

NASA Astrophysics Data System (ADS)

Ezat, M.; Rasmussen, T. L.; Skinner, L.; Zamelczyk, K.

2017-12-01

Ocean ventilation in the Arctic Mediterranean via transformation of northward inflowing warm Atlantic surface water into cold deep water affects regional climate, large-scale atmospheric circulation and carbon storage in the deep ocean. Radiocarbon dating of benthic foraminifera has been used to suggest a near-cessation of Arctic Ocean ventilation during the Last Glacial Maximum. During the last deglaciation episodic surges of this Arctic `aged' glacial deep water into the Nordic Seas and the subpolar North Atlantic Ocean may have occurred (Thornalley et al., 2011, 2015; Science). A recent study from the SE Norwegian Sea and the Iceland Basin has revealed large radiocarbon age differences between different benthic foraminiferal species during the last deglaciation (Ezat et al., 2017; Paleoceanography), which arguments for a re-evaluation of previous bottom-water radiocarbon ventilation age reconstructions from the region. Here, we present new species-specific benthic and planktic foraminiferal radiocarbon dates from the central Fram Strait and the SE Norwegian Sea for the past 35 kyr. Several lines of evidence in this new dataset demonstrate that the previously suggested `extreme aging' of >6000 14C years in the Arctic Mediterranean is most likely erroneous. In addition, benthic-planktic age offsets in the deep central Fram Strait display a remarkable decrease from 1300-2300 14C years in late Marine Isotope Stage (MIS) 3 to 0-500 14C year in MIS 2, which correlates with a decrease in benthic d13C and reduction in the benthic-planktic d18O gradient. We are in the process of compiling/screening published ventilation age reconstructions from the Arctic Mediterranean and the subpolar North Atlantic in the light of our new results in order to establish a basin-scale evolution of ocean ventilation since late MIS 3 in this region.

Stochastic Simulation Using @ Risk for Dairy Business Investment Decisions

USDA-ARS?s Scientific Manuscript database

A dynamic, stochastic, mechanistic simulation model of a dairy business was developed to evaluate the cost and benefit streams coinciding with technology investments. The model was constructed to embody the biological and economical complexities of a dairy farm system within a partial budgeting fram...

The SEURAT-1 Approach towards Animal Free Human Safety Assessment

EPA Science Inventory

SEURAT-1 is a European public-private research consortium that is working towards animal-free testing of chemical compounds and the highest level of consumer protection. A research strategy was formulated based on the guiding principle to adopt a toxicological mode-of-action fram...

Watershed Central: An Integrated Watershed Assessment and Management Website (Columbus, OH workshop).

EPA Science Inventory

The U.S.EPA’s Office of Water (OW), Office of Research and Development (ORD), and Office of Environmental Information (OEI) have teamed together with other Federal Agencies, state and local agencies, tribal agencies, and non-government organizations, to develop an integrated fram...

Training a Joint and Expeditionary Mindset

DTIC Science & Technology

2006-12-01

associated with the JEM constructs and for using them to create effective computer-mediated training scenarios. The pedagogic model enables development of...ensure the instructional rigor of scenarios and provide a sound basis for determining performance indicators. The pedagogical model enables development...and Subordinate Constructs ........................................................................... 3 Pedagogical Fram ew ork

A conceptual framework that links pollinator foraging behavior to gene flow

USDA-ARS?s Scientific Manuscript database

In insect-pollinated crops such as alfalfa, a better understanding of how pollinator foraging behavior affects gene flow could lead to the development of management strategies to reduce gene flow and facilitate the coexistence of distinct seed-production markets. Here, we introduce a conceptual fram...

The role of summer surface wind anomalies in the summer Arctic sea ice extent in 2010 and 2011

NASA Astrophysics Data System (ADS)

Ogi, M.; Wallace, J. M.

2012-12-01

Masayo Ogi 1 and John M. Wallace 2 masayo.ogi@jamstec.go.jp wallace@atmos.washington.edu 1Japan Agency for Marine-Earth Science and Technology, Yokohama, Japan 2 Department of Atmospheric Sciences, University of Washington, Seattle, Washington The seasonal evolutions of Arctic sea ice extent (SIE) during the summers of 2010 and 2011 are contrasted with that in 2007. The June SIE in 2010 was lower than that in 2007 and was the lowest for that calendar month in the 32-year (1979-2010) record. The September SIE in 2010 would have set a new record low had it not been for the fact that the ice retreated more slowly during the summer months in that year than it did in 2007. Hence from early July onward, the SIE in 2010 remained at levels above those observed in 2007. The SIE minimum in September 2010 proved to be the third lowest on record, eclipsed by values in both 2007 and 2008. In spring and summer of 2011, the Arctic SIE was as low as it was in 2007, but the SIE in September 2011 did not reach record low levels. The SIE minimum in 2011 proved to be the second lowest on record for the period of 1979-2011. Summertime atmospheric conditions play an important role in controlling the variations in Arctic SIE. In a previous study based on statistical analysis of data collected prior to 2007, we showed that anticyclonic summertime circulation anomalies over the Arctic Ocean during the summer months favor low September SIE. We also found that the record-low ice summer year 2007 was characterized by a strong anticyclonic circulation anomaly, accompanied by an Ekman drift of ice out of the marginal seas toward the central Arctic and eventually toward the Fram Strait, as evidenced by the tracks of drifting buoys. Here we assess the extent to which year-to-year differences in summer winds over the Arctic might have contributed to the differing rates of retreat of ice during the summers of 2007, 2010, and 2011. Our results show that the May-June (MJ) pattern in 2010 is characterized by strong anticyclonic wind anomalies over the Arctic Ocean. The corresponding pattern for July-August-September (JAS) is dominated by a cyclonic gyre centered over the Kara Sea. The corresponding patterns for 2007 are weak in MJ and strongly anticyclonic in JAS. The JJA pattern in 2011 is characterized by anticyclonic wind anomalies over the Arctic directed toward the Fram Strait, whereas the September pattern exhibits wind anomalies directed away from the Fram Strait across the central Arctic Ocean toward the Chukchi Sea. The corresponding patterns for 2007 are strongly anticyclonic and directed toward the Fram Strait in both JJA and September. In the absence of the late season push by the winds, the ice did not retreat quite as far in 2011 as it did in 2007. We have shown evidence that low level winds over the Arctic play an important role in mediating the rate of retreat of sea ice during summer. Anomalous anticyclonic flow over the interior of the Arctic directed toward the Fram Strait favors rapid retreat and vice versa. We have argued that the relative rankings of the September SIE for the years 2007, 2010 and 2011 are largely attributable to the differing rates of decrease of SIE during these summers, which are a consequence of year-to-year differences in the seasonal evolution of summertime winds over the Arctic.

Sea Ice, Climate and Fram Strait

NASA Technical Reports Server (NTRS)

Hunkins, K.

1984-01-01

When sea ice is formed the albedo of the ocean surface increases from its open water value of about 0.1 to a value as high as 0.8. This albedo change effects the radiation balance and thus has the potential to alter climate. Sea ice also partially seals off the ocean from the atmosphere, reducing the exchange of gases such as carbon dioxide. This is another possible mechanism by which climate might be affected. The Marginal Ice Zone Experiment (MIZEX 83 to 84) is an international, multidisciplinary study of processes controlling the edge of the ice pack in that area including the interactions between sea, air and ice.

ToxPlorerTM: A Comprehensive Knowledgebase of Toxicity Pathways Using Ontology-driven Information Extraction

EPA Science Inventory

Realizing the potential of pathway-based toxicity testing requires a fresh look at how we describe phenomena leading to adverse effects in vivo, how we assess them in vitro and how we extrapolate them in silico across chemicals, doses and species. We developed the ToxPlorer™ fram...

The role of simulated small-scale ocean variability in inverse computations for ocean acoustic tomography.

PubMed

Dushaw, Brian D; Sagen, Hanne

2017-12-01

Ocean acoustic tomography depends on a suitable reference ocean environment with which to set the basic parameters of the inverse problem. Some inverse problems may require a reference ocean that includes the small-scale variations from internal waves, small mesoscale, or spice. Tomographic inversions that employ data of stable shadow zone arrivals, such as those that have been observed in the North Pacific and Canary Basin, are an example. Estimating temperature from the unique acoustic data that have been obtained in Fram Strait is another example. The addition of small-scale variability to augment a smooth reference ocean is essential to understanding the acoustic forward problem in these cases. Rather than a hindrance, the stochastic influences of the small scale can be exploited to obtain accurate inverse estimates. Inverse solutions are readily obtained, and they give computed arrival patterns that matched the observations. The approach is not ad hoc, but universal, and it has allowed inverse estimates for ocean temperature variations in Fram Strait to be readily computed on several acoustic paths for which tomographic data were obtained.

Multiple slope failures shaped the lower continental slope offshore NW Svalbard in the Fram Strait

NASA Astrophysics Data System (ADS)

Osti, Giacomo; Mienert, Jürgen; Forwick, Matthias; Sverre Laberg, Jan

2016-04-01

Bathymetry data show that the lower slope (between 1300 m and 3000 m water depth) of the NW-Svalbard passive margin has been affected by multiple slope failure events. The single events differ in terms of extension, volume of mobilized sediments, morphology of the slide scar, run-out distance and age. As for several mega-scale and minor Arctic slides, the trigger mechanism is still speculative and may include high sedimentation rates, dissociation of gas hydrates, excess pore pressure, or earthquakes caused by isostatic rebound. In this study, we discuss the potential trigger mechanisms that have led to the multiple slope failure events within what we suggest to be named the Fram Strait Slide Complex. The slide complex lies in proximity to the tectonically active Spitsbergen Fracture Zone where earthquakes events, occurrences of potential weak layers in the sediment column, low sedimentation rates, and extended gas hydrate-bearing sediments may all have contributed to the causes leading to multiple slope failures. Preliminary results obtained from 14C dating on N. pachyderma sin. from sediment cores from the Spitsbergen Fracture Zone slides (SFZS 1 and 2), coupled with sub-bottom profiler data (frequency 9 to 15 KHz) show that the two shallowest glide planes within one of the observed slide scars failed ~100,000 and ~115,000 yr BP. Whilst SFZS 1 affected an area of 750 km2 mobilizing a total sediment volume of 40 km3, SFZS 2 moved an area of 230 km2 with a sediment volume of 4.5 km3.

Results of the Sea Ice Model Intercomparison Project: Evaluation of sea ice rheology schemes for use in climate simulations

NASA Astrophysics Data System (ADS)

Kreyscher, Martin; Harder, Markus; Lemke, Peter; Flato, Gregory M.

2000-05-01

A hierarchy of sea ice rheologies is evaluated on the basis of a comprehensive set of observational data. The investigations are part of the Sea Ice Model Intercomparison Project (SIMIP). Four different sea ice rheology schemes are compared: a viscous-plastic rheology, a cavitating-fluid model, a compressible Newtonian fluid, and a simple free drift approach with velocity correction. The same grid, land boundaries, and forcing fields are applied to all models. As verification data, there are (1) ice thickness data from upward looking sonars (ULS), (2) ice concentration data from the passive microwave radiometers SMMR and SSM/I, (3) daily buoy drift data obtained by the International Arctic Buoy Program (IABP), and (4) satellite-derived ice drift fields based on the 85 GHz channel of SSM/I. All models are optimized individually with respect to mean drift speed and daily drift speed statistics. The impact of ice strength on the ice cover is best revealed by the spatial pattern of ice thickness, ice drift on different timescales, daily drift speed statistics, and the drift velocities in Fram Strait. Overall, the viscous-plastic rheology yields the most realistic simulation. In contrast, the results of the very simple free-drift model with velocity correction clearly show large errors in simulated ice drift as well as in ice thicknesses and ice export through Fram Strait compared to observation. The compressible Newtonian fluid cannot prevent excessive ice thickness buildup in the central Arctic and overestimates the internal forces in Fram Strait. Because of the lack of shear strength, the cavitating-fluid model shows marked differences to the statistics of observed ice drift and the observed spatial pattern of ice thickness. Comparison of required computer resources demonstrates that the additional cost for the viscous-plastic sea ice rheology is minor compared with the atmospheric and oceanic model components in global climate simulations.

Regional and inter-annual variability in Atlantic zooplankton en route to the Arctic Ocean: potential effects of multi-path Atlantic water advection through Fram Strait and the Barents Sea

NASA Astrophysics Data System (ADS)

Kwasniewski, Slawomir; Gluchowska, Marta; Trudnowska, Emilia; Ormanczyk, Mateusz; Walczowski, Waldemar; Beszczynska-Moeller, Agnieszka

2016-04-01

The Arctic is among the regions where the climate change effects on ecosystem will be the most rapid and consequential, with Arctic amplification recognized as an integral part of the process. Great part of the changes are forced by advection of warm waters from the North Atlantic and the expected modifications of Arctic marine ecosystem will be induced not only by changing environmental conditions but also as a result of introducing Atlantic biota. Thus, the knowledge of physical and biological heterogeneity of Atlantic inflow is requisite for understanding the effects of climate change on biological diversity and ecosystem functioning in the Arctic. The complex and variable two-branched structure of the Atlantic Water flow via Fram Strait and the Barents Sea most likely has a strong influence on the ocean biology in these regions, especially in the pelagic realm. Zooplankton are key components of marine ecosystems which form essential links between primary producers and grazer/predator consumers, thus they are important for functioning of the biological carbon pump. Changes in zooplankton distribution and abundance may have cascading effects on ecosystem functioning, with regulatory effects on climate. Based on data collected in summers of 2012-2014, within the scope of the Polish-Norwegian PAVE research project, we investigate zooplankton distribution, abundance and selected structural characteristics of communities, in relation to water mass properties in the Atlantic Water complex flow to the Arctic Ocean. The main questions addressed here are: what are the differences in zooplankton patterns between the Fram Strait and Barents Sea branches, and how does the inter-annual variability of Atlantic Water advection relate to changes in zooplankton? The results of the investigation are precondition for foreseeing changes in the pelagic realm in the Arctic Ocean and are necessary for constructing and tuning plankton components of ecosystem models.

The Very Late Eocene Opening of Fram Strait between the Arctic Ocean and the Nordic Seas: Linkages with the Popigai Impact

NASA Astrophysics Data System (ADS)

Hillaire-Marcel, C.; Poirier, A.

2013-12-01

The transition from the Eocene Arctic Lake to the Arctic Ocean through the opening of Fram Strait, initially dated at ca. 18 Ma based on palynological inferences (Moran et al., 2004, Nature 441, 601-605), has been recently assigned to the very late Eocene (~ 36 Ma) based on Os-isotope stratigraphy and Re-Os isochron ages of sediments from the IODP-ACEX core (Lomonosov Ridge) (Poirier & Hillaire-Marcel, 2011, GRL 38, L14607). Here, we examine the potential linkages of this event with the Popigai meteoritic impact from northeastern Siberia, which has been dated independently at 35.7×0.2 Ma (Bottomley et al. 1997, Nature 338, 365-368). Noteworthy is the fact that in the earliest marine sediments of the ACEX core, the Os-isotope stratigraphy records an isotopic excursion which we tentatively assigned to the chondritic impactor of Popigai. Sr and Pb isotope signatures of detrital sediments (i.e., following the removal of exchangeable fractions) were thus used to further document the sources of terrigenous sediments deposited before, during, and after the transition episode. Above and below the lacustrine/marine boundary, we note relatively constant source provenances (or mixture of sources), implying that relative contributions from regional detrital sedimentary sources, thus relative erosion rates over surrounding continents, did not change much at a Ma-long time scale. On the other hand, a sharp change highlights the lacustrine/marine transition, with an abrupt shift to low values in 87Sr/88Sr, also marked by a (smaller) excursion in all three 204Pb-normalised lead isotopes values (corrected for in-situ decay of U). This isotopic excursion might also be due to the Popigai chondritic Impactor. The impact-related ejection over basaltic target materials would have produced the particulate matter of suitable composition (Wooden et al. 1993, GCA 57, 3677-3704) to account for the isotopic excursion observed. A first order estimate of the Popigai impact yields a value of ~ 10^8 megatons, resulting in a potential seismic event in the Fram Strait area with a magnitude > 10, likely to have resulted in major faulting in the area, thus possibly leading to the opening of the Strait. This very late Eocene opening of Fram Strait, would suggest a potential role of the Arctic basin in the inception of the Atlantic Meridional Overturning Circulation. With this new chronology, the entry of the Earth in the "cold house" system of the Early Oligocene, and the early indices for ice-rafting, might have being nearly synchronous in the Arctic and the circum-Antarctica.

A modelling study of the influence of anomalous wind forcing over the Barents Sea on the Atlantic water flow to the Arctic Ocean in the period 1979-2004

NASA Astrophysics Data System (ADS)

Marciniak, Jakub; Schlichtholz, Pawel; Maslowski, Wieslaw

2016-04-01

Arctic climate system is influenced by oceanic heat transport with the Atlantic water (AW) streaming towards the Arctic Ocean in two branches, through the deep Fram Strait and the shallow Barents Sea. In Fram Strait, the AW submerges below the Polar surface water and then flows cyclonically along the margin of the Arctic Ocean as a subsurface water mass in the Arctic Slope Current. In contrast to the Fram Strait branch, which is the major source of heat for the Arctic Ocean, most of the heat influx to the Barents Sea through the Barents Sea opening (BSO) is passed to the atmosphere. Only cold remnants of AW outflow to the Arctic Ocean through the northeastern gate of the Barents Sea. Some AW entering the Barents Sea recirculates westward, contributing to an outflow from the Barents Sea through the BSO along the shelf slope south of Bear Island, in the Bear Island Slope Current. Even though the two-branched AW flow toward the Arctic Ocean has been known for more than a century, little is known about co-variability of heat fluxes in the two branches, its mechanisms and climatic implications. Recent studies indicate that the Bear Island Slope Current may play a role in this co-variability. Here, co-variability of the flow through the BSO and Fram Strait is investigated using a pan-Arctic coupled ice-ocean hindcast model run for the period 1979-2004 and forced with daily atmospheric data from the ECMWF. Significant wintertime co-variability between the volume transport in the Bear Island and Arctic slope currents and its link to wind forcing over the Barents Sea is confirmed. It is found that the volume transports in these currents are, however, not correlated in the annual mean and that the wintertime co-variability of these currents has no immediate effect on either the net heat flux through the BSO or the net heat flux divergence in the Barents Sea. It is shown that the main climatic effect of wind forcing over the northern Barents Sea shelf is to induce temperature anomalies in the Murman/West Novaya Zemlya current system on the eastern side of the Barents Sea. These anomalies affect sea ice in the eastern Barents Sea 1-3 months later, but are not completely lost on the interactions with the sea ice and local atmosphere. Statistically significant subsurface temperature anomalies driven by anomalous winds over the Barents Sea join, on their exit to the Arctic Ocean through St. Anna Trough, the Arctic Slope Current, in which they persist for several years.

CHAMPUS (Civilian Health and Medical Program of the Uniformed Services) Reform: Will It Work? An Analysis of the CHAMPUS Reform Initiative.

DTIC Science & Technology

1987-12-01

eterinarians, optometrists, podiatrists, pharmacists , psycologists, nurse practitioners, rhvsician assistants, and others. In addition, over 146,000 enlisted...and the uti -lization data needed for ood resource C. CONTROL OF HEALTH CARE COSTS 1-,- la c ot- regional fixed-price contracts is set forth by the fram

The Coast Artillery Journal. Volume 72, Number 2, February 1930

DTIC Science & Technology

1930-02-01

hmlisfar further study alang this line, we shall also.co.nfine ourselvesto the "cantact" effect of this agent, as distinguished fram what we may call its...study alang the lines we are nGW cansidering. Mustard is an aily liquid af abo.utthe cam-listencyaf heavy lubricating oil. Dispersed either by artillery

Innovations in the Assay of Un-Segregated Multi-Isotopic Grade TRU Waste Boxes with SuperHENC and FRAM Technology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simpson, A. P.; Barber, S.; Abdurrahman, N. M.

2006-07-01

The Super High Efficiency Neutron Coincidence Counter (SuperHENC) was originally developed by BIL Solutions Inc., Los Alamos National Laboratory (LANL) and Rocky Flats Environmental Technology Site (RFETS) for assay of transuranic (TRU) waste in Standard Waste Boxes (SWB) at Rocky Flats. This mobile system was a key component in the shipment of over 4,000 SWBs to the Waste Isolation Pilot Plant (WIPP) in Carlsbad, New Mexico. The system was WIPP certified in 2001 and operated at the site for four years. The success of this system, a passive neutron coincidence counter combined with high resolution gamma spectroscopy, led to themore » order of two new units, delivered to Hanford in 2004. Several new challenges were faced at Hanford: For example, the original RFETS system was calibrated for segregated waste streams such that metals, plastics, wet combustibles and dry combustibles were separated by 'Item Description Codes' prior to assay. Furthermore, the RFETS mission of handling only weapons grade plutonium, enabled the original SuperHENC to benefit from the use of known Pu isotopics. Operations at Hanford, as with most other DOE sites, generate un-segregated waste streams, with a wide diversity of Pu isotopics. Consequently, the new SuperHENCs are required to deal with new technical challenges. The neutron system's software and calibration methodology have been modified to encompass these new requirements. In addition, PC-FRAM software has been added to the gamma system, providing a robust isotopic measurement capability. Finally a new software package has been developed that integrates the neutron and gamma data to provide a final assay results and analysis report. The new system's performance has been rigorously tested and validated against WIPP quality requirements. These modifications, together with the mobile platform, make the new SuperHENC far more versatile in handling diverse waste streams and allow for rapid redeployment around the DOE complex. (authors)« less

Cenozoic pre-glacial tectonostratigraphy and erosion estimates for the northwestern Barents Sea

NASA Astrophysics Data System (ADS)

Lasabuda, Amando; Sverre Laberg, Jan; Knutsen, Stig-Morten

2017-04-01

The northwestern Barents Sea continental margin is located between Bjørnøya and Svalbard. It is a structurally complex area characterized by a series of highs and basins influenced by: 1) the formation of the Spitsbergen fold-and-thrust belt towards the north and the pull-apart basin, the Vestbakken Volcanic Province, to the south, and 2) the rifting and opening of the Fram Strait, the deep-water gateway connecting the Norwegian - Greenland Sea and the Arctic Ocean. This study incorporate newly available 2D seismic data as well as magnetic data, and aim to improve the understanding of the Cenozoic evolution of this area, including better constrain of the timing of the main sedimentation events of the Cenozoic basins and estimates of the volume of sediments involved and the corresponding rates of erosion of the drainage area. The Cenozoic development of this area is strongly related to the rifting and opening of the Norwegian-Greenland Sea. During the Paleocene-Eocene, the northwestern Barents Sea margin were subjected to compression/transpression when Greenland drifted towards Svalbard that led to uplift and the development of fold-and-thrust belt on Svalbard. Subsequently, from the Oligocene, a tectonic plate reorganization occurred, leading to crustal extension, sea floor spreading and opening of the Fram Strait west of Svalbard. The seismic data shows a pronounced sequence of Early - Mid Cenozoic, pre-glacial sediments overlying the oceanic crust west of Svalbard while to the east, the Svalbard platform and the Stappen High were subjected to erosion and probably acted as the main sediment source for the northwestern Barents Sea margin. The amount of erosion will be estimated from the study of the deposited sediment volumes and their inferred source area. We will then compare the sedimentation and erosion rates to rates from other parts of the Norwegian - Barents Sea - Svalbard margin as well as relevant modern systems. Furthermore, the Cenozoic paleo-geography will be reconstructed.

Chemical Stockpile Disposal Program. Chemical Weapons Movement History Compilation.

DTIC Science & Technology

1987-06-12

Arsenal, Edgewood Arsenal, and Dugway Proving Ground . (2) The Army has transferred agent fram certain munitions into other containers or munitions...Aberdeen Proving Ground , Maryland (Historical Volume). - ~ - - - - -.. , 27. Sea Dump of 700 Tons of Lewisite and Mustard , NAD, Concord, California, 1958... Proving Ground , Maryland (Historical Volumes). 42. SITREP File, SFTCM II, 1980; Chemical Agent Identification Sets (CAIS) Historical File; Information

Prediction of exercise-mediated changes in metabolic markers by gene polymorphism.

PubMed

Kahara, Toshio; Takamura, Toshinari; Hayakawa, Tetsuo; Nagai, Yukihiro; Yamaguchi, Hiromi; Katsuki, Tatsuo; Katsuki, Ken-ichi; Katsuki, Michio; Kobayashi, Ken-ichi

2002-08-01

The effects of regular physical exercise on obesity-associated metabolic abnormalities vary for each individual. In this study, we investigated whether genotypes of genes associated with obesity can predict the effects of exercise on changes in metabolic markers in healthy men. Healthy Japanese men (n=106) performed the exercise program at 50% of their maximal heart rate for 20-60 min a day, 2-3 days each week for 3 months. The levels of fasting plasma glucose (FPG) and serum leptin significantly decreased after the exercise program. Polymorphisms of the beta3-adrenergic receptor (beta3AR) and uncoupling protein-1 (UCP-1) genes were analyzed with RFLP methods. In the Trp/Trp genotype of the beta3AR gene, the levels of serum leptin, FPG and fructosamine (FrAm) decreased significantly after the exercise program, but not in the Arg/Arg genotype. In the AG heterozygote and the GG homozygote of the UCP-1 gene, FPG and FrAm levels were significantly reduced, respectively. In conclusion, gene polymorphism of the beta3AR and UCP-1 was found to be associated with the exercise-mediated improvement in glucose tolerance and leptin resistance in healthy Japanese men.

Evaluation of Data Retention Characteristics for Ferroelectric Random Access Memories (FRAMs)

NASA Technical Reports Server (NTRS)

Sharma, Ashok K.; Teverovsky, Alexander

2001-01-01

Data retention and fatigue characteristics of 64 Kb lead zirconate titanate (PZT)-based Ferroelectric Random Access Memories (FRAMs) microcircuits manufactured by Ramtron were examined over temperature range from -85 C to +310 C for ceramic packaged parts and from -85 C to +175 C for plastic parts, during retention periods up to several thousand hours. Intrinsic failures, which were caused by a thermal degradation of the ferroelectric cells, occurred in ceramic parts after tens or hundreds hours of aging at temperatures above 200 C. The activation energy of the retention test failures was 1.05 eV and the extrapolated mean-time-to-failure (MTTF) at room temperature was estimated to be more than 280 years. Multiple write-read cycling (up to 3x10(exp 7)) during the fatigue testing of plastic and ceramic parts did not result in any parametric or functional failures. However, operational currents linearly decreased with the logarithm of number of cycles thus indicating fatigue process in PZT films. Plastic parts, that had more recent date code as compared to ceramic parts, appeared to be using die with improved process technology and showed significantly smaller changes in operational currents and data access times.

Arctic Ocean circulation during the anoxic Eocene Azolla event

NASA Astrophysics Data System (ADS)

Speelman, Eveline; Sinninghe Damsté, Jaap; März, Christian; Brumsack, Hans; Reichart, Gert-Jan

2010-05-01

The Azolla interval, as encountered in Eocene sediments from the Arctic Ocean, is characterized by organic rich sediments ( 4wt% Corg). In general, high levels of organic matter may be caused by increased productivity, i.e. extensive growth of Azolla, and/or enhanced preservation of organic matter, or a combination of both. Anoxic (bottom) water conditions, expanded oxygen minimum zones, or increased sedimentation rates all potentially increase organic matter preservation. According to plate tectonic, bathymetric, and paleogeographic reconstructions, the Arctic Ocean was a virtually isolated shallow basin, with one possible deeper connection to the Nordic Seas represented by a still shallow Fram Strait (Jakobsson et al., 2007), hampering ventilation of the Arctic Basin. During the Azolla interval surface waters freshened, while at the same time bottom waters appear to have remained saline, indicating that the Arctic was highly stratified. The restricted ventilation and stratification in concert with ongoing export of organic matter most likely resulted in the development of anoxic conditions in the lower part of the water column. Whereas the excess precipitation over evaporation maintained the freshwater lid, sustained input of Nordic Sea water is needed to keep the deeper waters saline. To which degree the Arctic Ocean exchanged with the Nordic Seas is, however, still largely unknown. Here we present a high-resolution trace metal record (ICP-MS and ICP-OES) for the expanded Early/Middle Eocene section capturing the Azolla interval from Integrated Ocean Drilling Program (IODP) Expedition 302 (ACEX) drilled on the Lomonosov Ridge, central Arctic Ocean. Euxinic conditions throughout the interval resulted in the efficient removal of redox sensitive trace metals from the water column. Using the sedimentary trace metal record we also constrained circulation in the Arctic Ocean by assessing the relative importance of trace metal input sources (i.e. fluvial, eolian, and through seawater inflow). Excess vanadium accumulation during the Azolla event (80 ppm), basin volume and surface area, average vanadium sea (1.8 ppb) and river water (1.0 ppb) concentrations, together indicate that an inflow of Nordic Sea water of 0.2 Sv is needed to sustain vanadium levels. The same calculation using molybdenum gives an inflow of only 0.02 Sv. These low inflow rates imply Arctic Ocean (deep) water residence times of 2000 - 20000 years, respectively. Based on climate modeling we calculated a summed net amount of precipitation for the Eocene Arctic Basin (Precipitation - Evaporation + Runoff) of 0.46 Sv. Together these notions indicate that a compensating inflow of saline North Atlantic water occurred, accompanied by an outflow of more fresh waters, resulting in a bi-directional, two-layer flow through the (proto-) Fram Strait. Consequently, the limited exchange of water through the Fram Strait implies that a relatively low export productivity would have been sufficient to render Arctic bottom waters anoxic. Jakobsson, M., Backman, J., Rudels, B., Nycander, J., Frank, M., Mayer, L., Jokat, W., Sangiorgi, F., O'Regan, M., Brinkhuis, H., King, J., Moran, K. (2007). The early Miocene onset of a ventilated circulation regimen in the Arctic Ocean. Nature 447, 986-990.

Variations in the structural and functional diversity of zooplankton over vertical and horizontal environmental gradients en route to the Arctic Ocean through the Fram Strait.

PubMed

Gluchowska, Marta; Trudnowska, Emilia; Goszczko, Ilona; Kubiszyn, Anna Maria; Blachowiak-Samolyk, Katarzyna; Walczowski, Waldemar; Kwasniewski, Slawomir

2017-01-01

A multi-scale approach was used to evaluate which spatial gradient of environmental variability is the most important in structuring zooplankton diversity in the West Spitsbergen Current (WSC). The WSC is the main conveyor of warm and biologically rich Atlantic water to the Arctic Ocean through the Fram Strait. The data set included 85 stratified vertical zooplankton samples (obtained from depths up to 1000 metres) covering two latitudinal sections (76°30'N and 79°N) located across the multi-path WSC system. The results indicate that the most important environmental variables shaping the zooplankton structural and functional diversity and standing stock variability are those associated with depth, whereas variables acting in the horizontal dimension are of lesser importance. Multivariate analysis of the zooplankton assemblages, together with different univariate descriptors of zooplankton diversity, clearly illustrated the segregation of zooplankton taxa in the vertical plane. The epipelagic zone (upper 200 m) hosted plentiful, Oithona similis-dominated assemblages with a high proportion of filter-feeding zooplankton. Although total zooplankton abundance declined in the mesopelagic zone (200-1000 m), zooplankton assemblages in that zone were more diverse and more evenly distributed, with high contributions from both herbivorous and carnivorous taxa. The vertical distribution of integrated biomass (mg DW m-2) indicated that the total zooplankton biomass in the epipelagic and mesopelagic zones was comparable. Environmental gradients acting in the horizontal plane, such as the ones associated with different ice cover and timing of the spring bloom, were reflected in the latitudinal variability in protist community structure and probably caused differences in succession in the zooplankton community. High abundances of Calanus finmarchicus in the WSC core branch suggest the existence of mechanisms advantageous for higher productivity or/and responsible for physical concentration of zooplankton. Our results indicate that regional hydrography plays a primary role in shaping zooplankton variability in the WSC on the way to the Arctic Ocean, with additional effects caused by biological factors related to seasonality in pelagic ecosystem development, resulting in regional differences in food availability or biological production between the continental slope and the deep ocean regions.

Ferroelectric memory evaluation and development system

NASA Astrophysics Data System (ADS)

Bondurant, David W.

Attention is given to the Ramtron FEDS-1, an IBM PC/AT compatible single-board 16-b microcomputer with 8-kbyte program/data memory implemented with nonvolatile ferroelectric dynamic RAM. This is the first demonstration of a new type of solid state nonvolatile read/write memory, the ferroelectric RAM (FRAM). It is suggested that this memory technology will have a significant impact on avionics system performance and reliability.

Connecting Polar Literature with Contemporary Research

NASA Astrophysics Data System (ADS)

Pfirman, S.; Bell, R.; Fowler, C.

2006-12-01

The public is fascinated with polar research, especially when it is linked with exploration, discovery, adventure, isolation, self-reliance, hardship, and exotic landscapes and biota. A powerful way to engage the public in appreciating current research is to link it with accounts of historical expeditions. We have been doing this at Barnard College, Columbia University, since 2003 through "Exploring the Poles," a First Year Seminar. The class investigates polar exploration at the turn of the last century by reading "Farthest North" by Nansen about his adventure with the Fram, "The Last Place on Earth" by Huntford about Scott and Amundsen's race to the South Pole, and "Endurance" by Lansing about Shackleton's journey. To bring polar conditions home for the students, they are assigned to expedition teams for specific years and the fates of the student "expeditions" are based on the actual environmental conditions as well as their own decisions. For example, in the Arctic, student teams navigate satellite images of coastal ice and then freeze their ships into the sea ice north of Siberia, where they then drift with the ice across the pole, re-creating the transit of the Fram. Because the conditions are based on actual data, natural variability causes different outcomes for different years, creating an element of suspense. Fates of the teams vary tremendously: some teams emerge safely as Nansen did at Fram Strait or reach Elephant Island as happened with Shackleton, while others nearly become hopelessly lost in the Arctic Beaufort Gyre or drift out to sea into the Antarctic Circumpolar Current. Interweaving history, science, and stories of past and present expeditions provides a meaningful connection with the otherwise remote polar regions. Evaluation shows that combining historical texts with current data and simulations is an extremely powerful way of engaging non-scientists in science, and explaining the role of science and the environment in decision- making. Students come to understand issues faced by leaders as they deal with environmental uncertainty, and they become interested in science as they find themselves at the mercy of the elements. The interaction between current research and historical experience as well as the physical and social environments has applications in both formal and informal educational venues.

MIZEX. A Program for Mesoscale Air-Ice-Ocean Interaction Experiments in Arctic Marginal Ice Zones. II. A Science Plan for a Summer Marginal Ice Zone Experiment in the Fram Strait/Greenland Sea: 1984.

DTIC Science & Technology

1983-05-01

size and thickness characteris- tics. N’ore complete analysis will require combin- ing ice data with data obtained by the oceano - graphic... sol concentration and microwave brightness tem- perature. A long-range aircraft and a light aircraft Hying from Spitzbergen will study mesoscale

Extraction of Late Summer Sea Ice Properties from Polarimetric SAR Features in C- and X-Band

NASA Astrophysics Data System (ADS)

Fors, Ane S.; Brekke, Camilla; Gerland, Sebastian; Doulgeris, Anthony P.; Eltoft, Torbjørn

2015-04-01

In this study we examine the potential use of six polarimetric features for interpretation of late summer sea ice types. Five high-resolution C and X-band scenes were recorded in the Fram Strait covering fast first-year and old sea ice. In addition sea ice thickness, surface roughness and melt pond fraction were collected during a helicopter flight at the study area. From the SAR scenes, six polarimetric features were extracted. Along sections of the track of the helicopter flight, the mean of the SAR features were compared to mean values of the properties measured during the helicopter flight. The results reveal relations between several of the SAR features and the geophysical properties measured in C-band, and weak relations in X-band.

LA-ICP-MS as Tool for Provenance Analyses in Arctic Marine Sediments

NASA Astrophysics Data System (ADS)

Wildau, Antje; Garbe-Schönberg, Dieter

2015-04-01

The hydraulic transport of sediments is a major geological process in terrestrial and marine systems and is responsible for the loss, redistribution and accumulation of minerals. Provenance analyses are a powerful tool for assessing the origin and dispersion of material in ancient and modern fluvial and marine sediments. Provenance-specific heavy minerals (e.g., zircon, rutile, tourmaline) can therefore be used to provide valuable information on the formation of ore deposits (placer deposits), and the reconstruction of paleogeography, hydrology, climate conditions and developments. The application of provenances analyses for the latter reason is of specific interest, since there is need for research on the progressing climate change, and heavy minerals represent good proxies for the evaluation of recent and past changes in the climate. The study of these fine particles provides information about potential regional or long distance transport paths, glacial / ice drift and current flows, freezing and melting events as well as depositional centers for the released sediments. Classic methods applied for provenance analyses are mapping of the presence / absence of diagnostic minerals, their grain size distribution, modal mineralogy and the analysis of variations in ratio of two or more heavy minerals. Electron microprobe has been established to discover changes in mineral chemistry of individual mineral phases, which can indicate fluctuations or differences in the provenance. All these methods bear the potential of high errors that lower the validity of the provenance analyses. These are for example the misclassification of mineral species due to undistinguishable optical properties or the limitations in the detection / variations of trace elements using the election microprobe. For this case study, marine sediments from the Arctic Ocean have been selected to test if LA-ICP-MS can be established as a key technique for precise and reliable provenance analyses. The Laptev Sea is known to be a "sea ice formation factory" and represents a perfect source area with numerous sediment loaded rivers draining into the Arctic Ocean. Mineral grains become trapped in the sea ice, which is transported to the Fram Strait, the outflow area of the Transpolar Drift System. Thus, minerals in the Fram Strait and in the Laptev Sea should have the same provenance. In both areas zircon, garnet, ilmenite, magnetite, tourmaline, pyroxene and amphibole were identified (amongst others). The vast majority of potential source areas and the widespread occurrence of these accessory and rock forming minerals result in the absolute need for a highly sensitive and precise method such as LA-ICP-MS. We report new data on the eligibility of selected heavy minerals for provenance analyses in the Arctic Ocean. Based on the individual trace element composition, REE-pattern and isotopic ratios, reflecting the conditions during formation, we report individual fingerprints for single mineral species. This enables us to allocate specific minerals from Fram Strait and from Laptev Sea to one provenance. Furthermore we evaluate the eligibility of different heavy minerals as a geochemical proxy in Arctic sediments for provenance analyses using LA-ICP-MS.

Comparison of Envisat ASAR and Submarine Sea Ice Thickness Statistics

NASA Astrophysics Data System (ADS)

Hughes, Nicolas E.; Rodrigues, Joao; Wadhams, Peter

2010-12-01

In April 2004 and March 2007 the Royal Navy sent the submarine HMS Tireless on missions into the Arctic Ocean. On both occasions the submarine traversed the area of remaining multi-year sea ice at latitude 85°N north of Greenland acquiring ice draft measurements using upward-looking sonar. The area is outside of the "Gore Box" used for the release of U.S. Submarine data and was beyond the latitude range of the radar altimeter satellites available at that time. This paper compares ice draft statistics with contemporary data from Envisat ASAR to evaluate the level of correlation between SAR backscatter and sea ice thickness. The decline in sea ice volume over the past decade has predominantly been caused by the loss of old multi-year ice due to increased outflow through Fram Strait. Although Tireless found little decrease in the overall ice thickness between 2004 and 2007, the ice rheology was significantly changed with greatly increased quantities of first- and second-year ice in 2007 than had been encountered in 2004. These are evident in changes to the ice draft probability density functions (PDFs) and the ice appearance as seen by the SAR, and presented here.

The Holocene Record of the Arctic Oscillation and a Possible Link to Solar Variability

NASA Astrophysics Data System (ADS)

Rand, J.; Darby, D. A.; Ortiz, J.; Cook, M. Y.; Keigwin, L.

2007-12-01

Detailed Fe grain provenance for a 19.9 meter long piston core (HLY02-JPC16) with about 17.5 m of Holocene sediment provides a sub-century scale resolution of the Arctic Oscillation (AO). The presence of Fe grains matched to Russian shelves fluctuates throughout this core, located 125 km north of Alaska in 1300 m water depth. High amounts of these Fe grains indicate a strong positive AO. While century scale fluctuations occur in the influx of Russian ice-rafted grains at this core site, a significant periodicity of about 1500 years exists that is similar to that of Be-10 in the Greenland ice cores. This begs the question as to how the AO might be linked to solar variations, especially such weak ones. The sources of sea ice rafting throughout the Holocene are compared to Modern sea ice samples and there is generally a good match. There is much greater heterogeneity in sources based on Fe grain provenance than other techniques for sourcing sea ice today. While the Laptev Sea is certainly an important sea ice entrainment area, it is by no means the only one and not even the most important over the long term. This distinction lies with northern Canadian sources, especially the Queen Elizabeth Islands facing the Arctic Ocean. The AO plays a major role in mixing sea ice from Russian and North American sources, especially during ++AO events. At these times, not only does the Trans Polar Drift swing closer to North America introducing sea ice from the Russian shelves such as the Laptev Sea to the Beaufort Gyre (BG), but it also aids in dragging some of the BG ice toward Fram Strait. This BG ice is a mix of North American and Russian ice and thus it is not surprising to find sediment from both sources in ice along the drift path of this ice moving toward Fram Strait.

Issues of Commonality. Volume II. Issue Analysis.

DTIC Science & Technology

1980-12-01

lubricating oil, and residual oil. 68 ° B Diesel fuel and kerosene make up what are known as the middle distillates. Jet fuels are blends from this...group of distillates which include some gasoline and some heavier oils. The range of hydrocarbons selected for this blending determines the "cut" of...the fuel. Wide-cut fuels are blended fram a wide range of hydrocarbons; narrow-cut fuels include only a small range of hydrocarbons from the

Radiation-Induced Gastrointestinal Death in the Monkey

DTIC Science & Technology

1959-06-01

muscularis mucosa FIGURE 9 could be identified in the histologic prep- One of the more severe cases of atrophic gastritis . arations. The bodies of the glands...sources into position and then was lowered rapidly The histologic preparations examined in this into the center of the field. The dose rate was 803 r...tributed over a spherical wire fram%. 𔄀 inches and one from the rectum. All histologic inter- in diameter. The dose rate at the center of pretations were

Toward Quantifying the Impact of Atmospheric Forcing on Arctic Sea Ice Variability Using the NPS 1/12 Degree Pan-Arctic Coupled Ice-Ocean Model

DTIC Science & Technology

2010-03-01

strong while the temperatures over Scandinavia and Europe (eastern Arctic) are warmer and winds are weaker than average (Serreze and Barry 2005...than the Fram Strait branch than previously thought. This could facilitate an increase in the frequency of storms reaching higher latitudes...REFERENCES Ackerman, J. T., 2008: Climate Change, National Security, and the Quadrennial Defense Review: Avoiding the Perfect Storm . Strategic Studies

US-ROK Action Sheet 34: Safeguards Application of a Hand-held Mechanically Cooled Germanium Spectrometer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dreyer, J.; Burks, M.; Ham, Y.

2015-10-20

This report summarizes results of Action Sheet 34 - for the cooperative efforts on the field testing and evaluation of a high-resolution, hand-held, gamma-ray spectrometer, known as SPG (Spectroscopic Planar Germanium), for safeguards application such as short notice inspections, UF6 analysis, enrichment determination, and other potential applications. The Spectroscopic Planar Germanium (SPG) has been demonstrated IAEA Physical Inventory Verification (PIV) in South Korea. This field test was a success and the feedback provided by KINAC, IAEA, and national laboratory staff was used to direct efforts to improve the instrument this year. Key points in this report include measurement results frommore » PIV, analysis of spectra with commercially available Ortec U235 and PC-FRAM, and completion of tripod and tungsten collimator and integration of user feedback.« less

Regional- and local-scale variations in benthic megafaunal composition at the Arctic deep-sea observatory HAUSGARTEN

NASA Astrophysics Data System (ADS)

Taylor, J.; Krumpen, T.; Soltwedel, T.; Gutt, J.; Bergmann, M.

2016-02-01

The Long-Term Ecological Research (LTER) observatory HAUSGARTEN, in the eastern Fram Strait, provides us the valuable ability to study the composition of benthic megafaunal communities through the analysis of seafloor photographs. This, in combination with extensive sampling campaigns, which have yielded a unique data set on faunal, bacterial, biogeochemical and geological properties, as well as on hydrography and sedimentation patterns, allows us to address the question of why variations in megafaunal community structure and species distribution exist within regional (60-110 km) and local (<4 km) scales. Here, we present first results from the latitudinal HAUSGARTEN gradient, consisting of three different stations (N3, HG-IV, S3) between 78°30‧N and 79°45‧N (2351-2788 m depth), obtained via the analysis of images acquired by a towed camera (OFOS-Ocean Floor Observation System) in 2011. We assess variability in megafaunal densities, species composition and diversity as well as biotic and biogenic habitat features, which may cause the patterns observed. While there were significant regional-scale differences in megafaunal composition and densities between the stations (N3=26.74±0.63; HG-IV=11.21±0.25; S3=18.34±0.39 individuals m-2), significant local differences were only found at HG-IV. Regional-scale variations may be due to the significant differences in ice coverage at each station as well as the different quantities of protein available, whereas local-scale differences at HG-IV may be a result of variation in bottom topography or factors not yet identified.

Image Understanding Research and Its Application to Cartography and Computer-Based Analysis of Aerial Imagery

DTIC Science & Technology

1983-05-01

Parallel Computation that Assign Canonical Object-Based Frames of Refer- ence," Proc. 7th it. .nt. Onf. on Artifcial Intellig nce (IJCAI-81), Vol. 2...Perception of Linear Struc- ture in Imaged Data ." TN 276, Artiflci!.a Intelligence Center, SRI International, Feb. 1983. [Fram75] J.P. Frain and E.S...1983 May 1983 D C By: Martin A. Fischler, Program Director S ELECTE Principal Investigator, (415)859-5106 MAY 2 21990 Artificial Intelligence Center

Arctic Physical Oceanography.

DTIC Science & Technology

1984-07-01

series of fluActuations. a 1 ate velocity was recorded -’ith bot "h fixed and rofig current meter systems . Current v eters eaere rigidly attached to 750-r...with the U.S. Navy Transit satellite navigation system two per hour. II _20. 00 " 00 Ice slotion - 5i 850 FRAM-I drill frock 0F 1500 Monned floe o...kilometers of such survey line was flown. system . In addition 200 km of continuous aeromagnetic lines Both sea ice and water were sampled for later were

Impact of Greenland orography on the Atlantic Meridional Overturning Circulation

NASA Astrophysics Data System (ADS)

Davini, Paolo; von Hardenberg, Jost; Filippi, Luca; Provenzale, Antonello

2015-04-01

We show that the absence of the Greenland Ice Sheet would have important consequences on the North Atlantic Ocean circulation, even without taking into account the effect of the freshwater input from ice melting. These effects are investigated in a 200-year long coupled ocean-atmosphere simulation with the high-resolution global climate model EC-Earth 3.0.1. Once a new equilibrium is established, cooling of Eurasia and of the North Atlantic and poleward shift of the subtropical jet are observed. These hemispheric changes are ascribed to a weakening of the Atlantic Meridional Overturning Circulation (AMOC) by about 20%. Such slowdown is associated to the freshening of the Arctic basin and to the related reduction in the freshwater export through the Fram Strait, as a result of the new wind pattern generated by the lower orography. This idealized experiment reveals the possibility of decreasing the AMOC by locally changing the surface winds.

Results and Implications of Mineralogical Models for Chemical Sediments at Meridiani Planum

NASA Technical Reports Server (NTRS)

Clark, B. C.; McLennan, S. M.; Morris, R. V.; Gellert, R.; Jolliff, B.; Knoll, A.; Lowenstein, T. K.; Ming, D. W.; Tosca, N. J.; Christensen, P. R.

2005-01-01

The Mars Exploration Rover (MER) "Opportunity" has explored chemically-enriched sedimentary outcrops at Meridiani Planum, Mars. In its first year, three different crater sites - Eagle, Fram and Endurance - have been explored. Nineteen high-interest outcrop rocks were investigated by first grinding a hole to reach the interior (using the Rock Abrasion Tool, RAT), and then conducting APXS (alpha particle x-ray spectrometry) analysis, MB (M ssbauer) analysis, and close up imaging (MI, microscopic imager). Sixteen elements and four Fe-bearing minerals were assayed to good accuracy in each sample, producing 380 compositional data points. The Miniature Thermal Emission Spectrometer (Mini- TES) obtained spectra on outcrop materials which provide direct indication of several mineral classes. Preliminary reports on Eagle crater and three RAT samples have been published. Chemical trends and a derived mineralogical model for all RAT d outcrop samples to date has been developed.

Ku band airborne radar altimeter observations of marginal sea ice during the 1984 Marginal Ice Zone Experiment

NASA Technical Reports Server (NTRS)

Drinkwater, Mark R.

1991-01-01

Pulse-limited, airborne radar data taken in June and July 1984 with a 13.8-GHz altimeter over the Fram Strait marginal ice zone are analyzed with the aid of large-format aerial photography, airborne synthetic aperture radar data, and surface observations. Variations in the radar return pulse waveforms are quantified and correlated with ice properties recorded during the Marginal Ice Zone Experiment. Results indicate that the wide-beam altimeter is a flexible instrument, capable of identifying the ice edge with a high degree of accuracy, calculating the ice concentration, and discriminating a number of different ice classes. This suggests that microwave radar altimeters have a sensitivity to sea ice which has not yet been fully exploited. When fused with SSM/I, AVHRR and ERS-1 synthetic aperture radar imagery, future ERS-1 altimeter data are expected to provide some missing pieces to the sea ice geophysics puzzle.

Multisensor comparison of ice concentration estimates in the marginal ice zone

NASA Technical Reports Server (NTRS)

Burns, B. A.; Cavalieri, D. J.; Gloersen, P.; Keller, M. R.; Campbell, W. J.

1987-01-01

Aircraft remote sensing data collected during the 1984 summer Marginal Ice Zone Experiment in the Fram Strait are used to compare ice concentration estimates derived from synthetic aperture radar (SAR) imagery, passive microwave imagery at several frequencies, aerial photography, and spectral photometer data. The comparison is carried out not only to evaluate SAR performance against more established techniques but also to investigate how ice surface conditions, imaging geometry, and choice of algorithm parameters affect estimates made by each sensor.Active and passive microwave sensor estimates of ice concentration derived using similar algorithms show an rms difference of 13 percent. Agreement between each microwave sensor and near-simultaneous aerial photography is approximately the same (14 percent). The availability of high-resolution microwave imagery makes it possible to ascribe the discrepancies in the concentration estimates to variations in ice surface signatures in the scene.

Variations of mesoscale and large-scale sea ice morphology in the 1984 Marginal Ice Zone Experiment as observed by microwave remote sensing

NASA Technical Reports Server (NTRS)

Campbell, W. J.; Josberger, E. G.; Gloersen, P.; Johannessen, O. M.; Guest, P. S.

1987-01-01

The data acquired during the summer 1984 Marginal Ice Zone Experiment in the Fram Strait-Greenland Sea marginal ice zone, using airborne active and passive microwave sensors and the Nimbus 7 SMMR, were analyzed to compile a sequential description of the mesoscale and large-scale ice morphology variations during the period of June 6 - July 16, 1984. Throughout the experiment, the long ice edge between northwest Svalbard and central Greenland meandered; eddies were repeatedly formed, moved, and disappeared but the ice edge remained within a 100-km-wide zone. The ice pack behind this alternately diffuse and compact edge underwent rapid and pronounced variations in ice concentration over a 200-km-wide zone. The high-resolution ice concentration distributions obtained in the aircraft images agree well with the low-resolution distributions of SMMR images.

Branching of Atlantic Water within the Greenland-Spitsbergen Passage: An estimate of recirculation

NASA Astrophysics Data System (ADS)

Manley, T. O.

1995-10-01

Atlantic Water (AW) supplies the largest source of heat, mass, and salt to the Arctic Ocean via Fram Strait (Greenland-Spitsbergen Passage), yet it represents only a fraction of the Atlantic Water that resides in the Greenland, Iceland, Norwegian, and Barents Seas. This is a result of both the branching of the central core of AW along its northward flow and the modification of its T-S signature through air-sea-ice interactions and internal mixing. This paper addresses the quantitative analysis of the three dominant Atlantic Water cores within Fram Strait and north of 76°N using an 11-year (1977 to 1987) hydrographic database. Spatial variations of heat, volume, and salt along its flow path of some 600 km showed that the major core of Atlantic Water that directly enters the Arctic Ocean (Svalbard branch) did not extend past 20°E. Of the 9719 km3 of Atlantic Water existing within the region, one third resided within the Svalbard branch; the remainder, 22% and 45%, were held within the Return Atlantic Current and the Yermak branches, respectively. Restricting the analysis to a southern limit of 79°N effectively removed the Return Atlantic Current and showed a nearly equal split between the two remaining branches. Work completed by Bourke et al. (1988) indicated that the Yermak branch is largely recirculated to the south; if true, this analysis supports Rudels' (1987) model estimate of a 50% recirculation of AW within this region.

Arctic Ocean Freshwater: How Robust are Model Simulations

NASA Technical Reports Server (NTRS)

Jahn, A.; Aksenov, Y.; deCuevas, B. A.; deSteur, L.; Haekkinen, S.; Hansen, E.; Herbaut, C.; Houssais, M.-N.; Karcher, M.; Kauker, F.;

Agglutinated Foraminifera indicate a deep bottom current over the Hovgaard Ridge, West of Spitsbergen

NASA Astrophysics Data System (ADS)

Kaminski, Michael; Frank, Niessen

2015-04-01

The Hovgård Ridge is situated in Fram Strait, west of Spitsbergen. The ridge either represents a submerged fragment of continental crust or an upwarped fragmant of ocean crust within the Fram Strait. Its crest rises to a water depth of approx. 1170 m. During Expedition 87 of the Icebreaker POLARSTERN in August 2014, a sediment-echosounding profile was recorded and a boxcore station was collected from the crest of Hovgård Ridge at 1169 m water depth. The surficial sediment at this station consists of dark yellowish brown pebbly-sandy mud with a minor admixture of biogenic components in the coarse fraction. Patches of large tubular foraminifera and isolated pebbles were clearly visible on the sediment surface. The sediment surface of the boxcore was covered with patches of large (>1 mm diameter) large tubular astrorhizids belonging mostly to the species Astrorhiza crassatina Brady, with smaller numbers of Saccorhiza, Hyperammina, and Psammosiphonella. Non-tubular species consist mainly of opportunistic forms such as Psammosphaera and Reophax. The presence of large suspension-feeding tubular genera as well as opportunistic forms, as well as sediment winnowing, point to the presence of a deep current at this locality that is strong enough to disturb the benthic fauna. This is confirmed by data obtained from sediment echosounding, which exhibit lateral variation of relative sedimentation rates within the Pleistocene sedimentary drape covering the ridge indicative of winnowing in a south-easterly direction.

Operation of a Hovercraft Scientific Platform Over Sea Ice in the Arctic Ocean Transpolar Drift (81 - 85N): The FRAM-2012 Experience

NASA Astrophysics Data System (ADS)

Hall, J. K.; Kristoffersen, Y.

2013-12-01

We have tested the feasibility of hovercraft travel through predominantly first year ice of the Transpolar Drift between 81°N - 85°N north of Svalbard. With 2-9 ridges per kilometer, our hovercraft (Griffon TD2000 Mark II), with an effective hover height of about 0.5 m, had to travel a distance 1.3 times the great circle distance between the point of origin and the final destination. Instantaneous speeds were mostly 5-7 knots. Two weeks later icebreaker Oden completed the same transit under conditions with no significant pressure in the ice at a speed mostly 1 knot higher than the hovercraft and travelled 1.2 times the great circle distance. The hovercraft spent 25 days monitoring micro-earthquake activity of the Arctic Mid-Ocean Ridge at a section of the spreading center where no seismicity has been recorded by the global seismograph network. More than ten small earthquake events per day were recorded. Visibility appears to be the most critical factor to hovercraft travel in polar pack ice. Improved control of hovercraft motion would substantially increase the potential usefulness of hovercraft in the sea ice environment. University of Bergen graduate student Gaute Hope emplacing one of the hydrophones in the triangular array used to locate small earthquakes over the Gakkel Ridge rift valley around 85N during FRAM-2012. The research hovercraft R/H SABVABAA is in the background.

A 26 million year gap in the central Arctic record at the greenhouse-icehouse transition: Looking for clues

USGS Publications Warehouse

Sangiorgi, F.; Brumsack, H.-J.; Willard, D.A.; Schouten, S.; Stickley, C.E.; O'Regan, M.; Reichart, G.-J.; Sinninghe, Damste J.S.; Brinkhuis, H.

2008-01-01

The Cenozoic record of the Lomonosov Ridge (central Arctic Ocean) recovered during Integrated Ocean Drilling Program (IODP) Expedition 302 revealed an unexpected 26 Ma hiatus, separating middle Eocene (???44.4 Ma) from lower Miocene sediments (???18.2 Ma). To elucidate the nature of this unconformity, we performed a multiproxy palynological (dinoflagellate cysts, pollen, and spores), micropaleontological (siliceous microfossils), inorganic, and organic (Tetra Ether Index of lipids with 86 carbon atoms (TEX86) and Branched and Isoprenoid Tetraether (BIT)) geochemical analysis of the sediments from ???5 m below to ???7 m above the hiatus. Four main paleoenvironmental. phases (A-D) are recognized in the sediments encompassing the unconformity, two below (A-B) and two above (C-D): (A) Below the hiatus, proxies show relatively warm temperatures, with Sea Surface Temperatures (TEX86-derived SSTs) of about 8??C and high fresh to brackish water influence. (B) Approaching the hiatus, proxies indicate a cooling trend (TEX86-derived SSTs of ???5??C), increased freshwater influence, and progressive shoaling of the Lomonosov Ridge drilling site, located close to or at sea level. (C) The interval directly above the unconformity contains sparse reworked Cretaceous to Oligocene dinoflagellate cysts. Sediments were deposited in a relatively shallow, restricted marine environment. Proxies show the simultaneous influence of both fresh and marine waters, with alternating oxic and anoxic conditions. Pollen indicates a relatively cold climate. Intriguingly, TEX86-derived SSTs are unexpectedly high, ???15-19??C. Such warm surface waters may be partially explained by the ingression of warmer North Atlantic waters after the opening of the Fram Strait during the early Miocene. (D) Sediments of the uppermost interval indicate a phase of extreme oxic conditions, and a well-ventilated environment, which occurred after the complete opening of the Fram Strait. Importantly, and in contrast with classical postrifting thermal subsidence models for passive margins, our data suggest that sediment erosion and/or nondeposition that generated the hiatus was likely due to a progressive shoaling of the Lomonosov Ridge. A shallow water setting both before and after the hiatus suggests that the Lomonosov Ridge remained at or near sea level for the duration of the gap in the sedimentary record. Interacting sea level changes and/ or tectonic activity (possibly uplift) must be invoked as possible causes for such a long hiatus. Copyright 2008 by the American Geophysical Union.

Pliocene-Pleistocene changes in Arctic sea-ice cover: New biomarker records from Fram Strait/Yermak Plateau (ODP Sites 911 and 912)

NASA Astrophysics Data System (ADS)

Stein, Ruediger; Fahl, Kirsten

2013-04-01

Recently, a novel and promising biomarker proxy for reconstruction of Arctic sea-ice conditions was developed and is based on the determination of a highly branched isoprenoid with 25 carbons (IP25; Belt et al., 2007). Following this pioneer IP25 study by Belt and colleagues, several IP25 studies of marine surface sediments and sediment cores as well as sediment trap samples from northpolar areas were carried out successfully and allowed detailed reconstruction of modern and late Quaternary sea ice variability in these regions (e.g., Massé et al., 2008; Müller et al., 2009, 2011; Vare et al., 2009; Belt et al., 2010; Fahl and Stein, 2012; for review see Stein et al., 2012). Here, we present new (low-resolution) biomarker records from Ocean Drilling Program (ODP) Sites 911 and 912, representing the Pliocene-Pleistocene time interval (including the interval of major intensification of Northern Hemisphere Glaciation near 2.7 Ma). These data indicate that sea ice of variable extent was present in the Fram Strait/southern Yermak Plateau area during most of the time period under investigation. In general, an increase in sea-ice cover seems to correlate with phases of extended late Pliocene-Pleistocene continental ice-sheets. At ODP Site 912, a significant increase in sea-ice extension occurred near 1.2 Ma (Stein and Fahl, 2012). Furthermore, our data support the idea that a combination of IP25 and open water, phytoplankton biomarker data ("PIP25 index"; Müller et al., 2011) may give more reliable and quantitative estimates of past sea-ice cover (at least for the study area). This study reveals that the novel IP25/PIP25 biomarker approach has potential for semi-quantitative paleo-sea ice studies covering the entire Quaternary and motivate to carry out further detailed high-resolution research on ODP/IODP material using this proxy. References Belt, S.T., Massé, G., Rowland, S.J., Poulin, M., Michel, C., LeBlanc, B., 2007. A novel chemical fossil of palaeo sea ice: IP25. Organic Geochemistry 38, 16-27. Belt, S.T., Vare, L.L., Massé, G., Manners, H.R., Price, J.C., MacLachlan, S.E., Andrews, J.T., Schmidt, S., 2010. Striking similarities in temporal changes to spring sea ice occurrence across the central Canadian Arctic Archipelago over the last 7000 years. Quaternary Science Reviews 29, 3489-3504. Fahl, K. and Stein, R., 2012. Modern seasonal variability and deglacial/Holocene change of central Arctic Ocean sea-ice cover: New insights from biomarker proxy records. Earth Planetary Science Letters 351-352C, 123-133, doi:10.1016/j.epsl.2012.07.009. Massé, G., Rowland, S.J., Sicre, M.-A., Jacob, J., Jansen, E., Belt, S.T., 2008. Abrupt climate changes for Iceland during the last millennium: Evidence from high resolution sea ice reconstructions. Earth Planetary Science Letters 269, 565-569. Müller, J., Massé, G., Stein, R., Belt, S.T., 2009. Variability of sea-ice conditions in the Fram Strait over the past 30,000 years. Nature Geoscience 2, 772-776. Müller, J., Wagner, A., Fahl, K., Stein, R., Prange, M., Lohmann, G., 2011. Towards quantitative sea ice reconstructions in the northern North Atlantic: A combined biomarker and numerical modelling approach. Earth Planetary Science Letters 306, 137-148. Stein, R. and Fahl, K., 2012. Biomarker proxy IP25 shows potential for studying entire Quaternary Arctic sea-ice history. Organic Geochemistry; doi: 10.1016/j.orggeochem.2012.11.005. Stein, R., Fahl, K., and Müller, J., 2012. Proxy reconstruction of Arctic Ocean sea ice history: "From IRD to IP25". Polarforschung 82, 37-71. Vare, L.L., Massé, G., Gregory, T.R., Smart, C.W., Belt, S.T., 2009. Sea ice variations in the central Canadian Arctic Archipelago during the Holocene. Quaternary Science Reviews 28, 1354-1366.

OPALS: A COTS-based Tech Demo of Optical Communications

NASA Technical Reports Server (NTRS)

Oaida, Bogdan

2012-01-01

I. Objective: Deliver video from ISS to optical ground terminal via an optical communications link. a) JPL Phaeton/Early Career Hire (ECH) training project. b) Implemented as Class-D payload. c) Downlink at approx.30Mb/s. II. Flight System a) Optical Head Beacon Acquisition Camera. Downlink Transmitter. 2-axis Gimbal. b) Sealed Container Laser Avionics Power distribution Digital I/O board III. Implementation: a) Ground Station - Optical Communications Telescope Laboratory at Table Mountain Facility b) Flight System mounted to ISS FRAM as standard I/F. Attached externally on Express Logistics Carrier.

Unmanned Aircraft Systems For CryoSat-2 Validation

NASA Astrophysics Data System (ADS)

Crocker, Roger Ian; Maslanik, James A.

2011-02-01

A suite of sensors has been assembled to map surface elevation with fine-resolution from small unmanned aircraft systems (UAS). The sensor package consists of a light detecting and ranging (LIDAR) instrument, an inertial measurement unit (IMU), a GPS module, and digital still and video cameras. It has been utilized to map ice sheet topography in Greenland and to measure sea ice freeboard and roughness in Fram Strait. Data collected during these campaigns illustrate its potential to compliment ongoing CryoSat-2 (CS-2) calibration and validation efforts.

Opportunity's Travels

NASA Technical Reports Server (NTRS)

2004-01-01

This overview map made from Mars Orbiter camera images illustrates the path that the Mars Exploration Rover Opportunity has taken from its first sol on the red planet through its 87th sol. After thoroughly examining its 'Eagle Crater' landing-site, the rover moved onto the plains of Meridiani Planum, stopping to examine a curious trough and a target within it called 'Anatolia.' Following that, Opportunity approached and remotely studied the rocky dish called 'Fram Crater.' As of its 91st sol (April 26, 2004), the rover sits 160 meters (about 525 feet) from the rim of 'Endurance Crater.'

Nonvolatile Memory Technology for Space Applications

NASA Technical Reports Server (NTRS)

Oldham, Timothy R.; Irom, Farokh; Friendlich, Mark; Nguyen, Duc; Kim, Hak; Berg, Melanie; LaBel, Kenneth A.

2010-01-01

This slide presentation reviews several forms of nonvolatile memory for use in space applications. The intent is to: (1) Determine inherent radiation tolerance and sensitivities, (2) Identify challenges for future radiation hardening efforts, (3) Investigate new failure modes and effects, and technology modeling programs. Testing includes total dose, single event (proton, laser, heavy ion), and proton damage (where appropriate). Test vehicles are expected to be a variety of non-volatile memory devices as available including Flash (NAND and NOR), Charge Trap, Nanocrystal Flash, Magnetic Memory (MRAM), Phase Change--Chalcogenide, (CRAM), Ferroelectric (FRAM), CNT, and Resistive RAM.

Purification of the Alpha Glycerophosphate Oxidase from African Trypanosomes

DTIC Science & Technology

1988-02-02

remo~val of all unattached enzymes , the GPO would be eluted with a buffer containing the substrate a- GP. Cyancqen bromide activated Sepharose 4B was...released upon eluticn with a buffer cm-xtaining 100 rm of a-GP. Unfortunately, in these experiments, trypan blue was eluted from the colmn and the enzyme ...borate buffer (pH 8.0), there was no leakage of the ligand but the GPO was not released fram the colun when eluted with 10aM c-GP. Enzyme assays of the

Thiosulfate as an Antidote to Mustard Poisoning, A Review of the Literature.

DTIC Science & Technology

1982-09-01

FRANCISCO CA UNCLASSIFIED K D MCKINLEY ET AL. SEP 82 LRIR-127 F/G 61209 N MENOMONEE NONIEhhhhhhhhhEND 1168 UL 1.0. * 1.25 I 1,1.6 MICROCOPY RESOLUTION TEST...ORGANIZATION NAME AND ADDRESS 10. PRORA ELEMENT. PROJECT, TASK AREA &J’WORC UNIT N UMSIERS Division of Research Support, Letterman ArmyPojN/3124A7 Institute...block 2,If different fram Report) I& SUPPLI111ENTARY NOTES I9. KEY WORDS (Centinue n reverse side If natessy and identlity5 b ock number) Sodium

dfnWorks: A discrete fracture network framework for modeling subsurface flow and transport

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hyman, Jeffrey D.; Karra, Satish; Makedonska, Nataliia

DFNWORKS is a parallelized computational suite to generate three-dimensional discrete fracture networks (DFN) and simulate flow and transport. Developed at Los Alamos National Laboratory over the past five years, it has been used to study flow and transport in fractured media at scales ranging from millimeters to kilometers. The networks are created and meshed using DFNGEN, which combines FRAM (the feature rejection algorithm for meshing) methodology to stochastically generate three-dimensional DFNs with the LaGriT meshing toolbox to create a high-quality computational mesh representation. The representation produces a conforming Delaunay triangulation suitable for high performance computing finite volume solvers in anmore » intrinsically parallel fashion. Flow through the network is simulated in dfnFlow, which utilizes the massively parallel subsurface flow and reactive transport finite volume code PFLOTRAN. A Lagrangian approach to simulating transport through the DFN is adopted within DFNTRANS to determine pathlines and solute transport through the DFN. Example applications of this suite in the areas of nuclear waste repository science, hydraulic fracturing and CO 2 sequestration are also included.« less

dfnWorks: A discrete fracture network framework for modeling subsurface flow and transport

DOE PAGES

Hyman, Jeffrey D.; Karra, Satish; Makedonska, Nataliia; ...

2015-11-01

DFNWORKS is a parallelized computational suite to generate three-dimensional discrete fracture networks (DFN) and simulate flow and transport. Developed at Los Alamos National Laboratory over the past five years, it has been used to study flow and transport in fractured media at scales ranging from millimeters to kilometers. The networks are created and meshed using DFNGEN, which combines FRAM (the feature rejection algorithm for meshing) methodology to stochastically generate three-dimensional DFNs with the LaGriT meshing toolbox to create a high-quality computational mesh representation. The representation produces a conforming Delaunay triangulation suitable for high performance computing finite volume solvers in anmore » intrinsically parallel fashion. Flow through the network is simulated in dfnFlow, which utilizes the massively parallel subsurface flow and reactive transport finite volume code PFLOTRAN. A Lagrangian approach to simulating transport through the DFN is adopted within DFNTRANS to determine pathlines and solute transport through the DFN. Example applications of this suite in the areas of nuclear waste repository science, hydraulic fracturing and CO 2 sequestration are also included.« less

Variations in freshwater pathways from the Arctic Ocean into the North Atlantic Ocean

NASA Astrophysics Data System (ADS)

Wang, Zeliang; Hamilton, James; Su, Jie

2017-06-01

Understanding the mechanisms that drive exchanges between the Arctic Ocean and adjacent oceans is critical to building our knowledge of how the Arctic is reacting to a warming climate, and how potential changes in Arctic Ocean freshwater export may impact the AMOC (Atlantic Meridional Overturning Circulation). Here, freshwater pathways from the Arctic Ocean to the North Atlantic are investigated using a 1 degree global model. An EOF analysis of modeled sea surface height (SSH) demonstrates that while the second mode accounts for only 15% of the variability, the associated geostrophic currents are strongly correlated with freshwater exports through CAA (Canadian Arctic Archipelago; r = 0.75), Nares Strait (r = 0.77) and Fram Strait (r = -0.60). Separation of sea level into contributing parts allows us to show that the EOF1 is primarily a barotropic mode reflecting variability in bottom pressure equivalent sea level, while the EOF2 mode reflects changes in steric height in the Arctic Basin. This second mode is linked to momentum wind driven surface current, and dominates the Arctic Ocean freshwater exports. Both the Arctic Oscillation and Arctic Dipole atmospheric indices are shown to be linked to Arctic Ocean freshwater exports, with the forcing associated with the Arctic Dipole reflecting the out-of-phase relationship between transports through the CAA and those through Fram Strait. Finally, observed freshwater transport variation through the CAA is found to be strongly correlated with tide gauge data from the Beaufort Sea coast (r = 0.81), and with the EOF2 mode of GRACE bottom pressure data (r = 0.85) on inter-annual timescales.

Microzooplankton abundance, composition and trophic interactions with phytoplankton and pelagic copepods in the ice-covered and open waters of the Eastern Fram Strait.

NASA Astrophysics Data System (ADS)

Franzè, G.; Lavrentyev, P.; Svensen, C.; Moore, F. B.

2016-02-01

Microzooplankton distribution and trophodynamics were examined in the Fram Strait in May and September 2014 as part of the Carbon Bridge multidisciplinary program focused on the biological effects of the Atlantic water transfer to the Arctic Ocean. Samples of microzooplankton were collected along three longitudinal transects from the slope to the ice edge and crossed the Western Spitzbergen Current (WSC). Integrated microzooplankton biomass in the upper 50 m ranged from 0.19 mg C m-2 above the slope to 3.22 mg C m-2 within WSC. Mixotrophic oligotrich ciliates from the genus Strombidium comprised most of the biomass and reached their subsurface maximum of 78,000 cells L-1 and 206 µg C L-1 in the Atlantic water. This is the highest volumetric biomass of microzooplankton reported from the polar seas so far. Large heterotrophic dinoflagellates Gyrodinium and Protoperidinium were also abundant at several stations. Microzooplankton herbivory rates measured in shipboard dilution experiments ranged from non-detectable within the bloom of Phaeocystis pouchetii to >100% of phytoplankton growth. Overall, the herbivory and production rates were nearly matched and increased from 0.2 d-1 in May to > 1.0 d-1 in September. The Atlantic copepod Calanus finmarchicus showed a clear preference for ciliates under the ice and obtained nearly 80% of its carbon-based diet from microzooplankton. These preliminary results support the idea that the microbial food web plays a central role in the marine carbon cycle in the Arctic.

Seasonal and Interannual Variations of Sea Ice Mass Balance From the Central Arctic to the Greenland Sea

NASA Astrophysics Data System (ADS)

Lei, Ruibo; Cheng, Bin; Heil, Petra; Vihma, Timo; Wang, Jia; Ji, Qing; Zhang, Zhanhai

2018-04-01

The seasonal evolution of sea ice mass balance between the Central Arctic and Fram Strait, as well as the underlying driving forces, remain largely unknown because of a lack of observations. In this study, two and three buoys were deployed in the Central Arctic during the summers of 2010 and 2012, respectively. It was established that basal ice growth commenced between mid-October and early December. Annual basal ice growth, ranging from 0.21 to 1.14 m, was determined mainly by initial ice thickness, air temperature, and oceanic heat flux during winter. An analytic thermodynamic model indicated that climate warming reduces the winter growth rate of thin ice more than for thick ice because of the weak thermal inertia of the former. Oceanic heat flux during the freezing season was 2-4 W m-2, which accounted for 18-31% of the basal ice energy balance. We identified two mechanisms that modified the oceanic heat flux, i.e., solar energy absorbed by the upper ocean during summer, and interaction with warm waters south of Fram Strait; the latter resulted in basal ice melt, even in winter. In summer 2010, ice loss in the Central Arctic was considerable, which led to increased oceanic heat flux into winter and delayed ice growth. The Transpolar Drift Stream was relatively weak in summer 2013. This reduced sea ice advection out of the Arctic Ocean, and it restrained ice melt because of the cool atmospheric conditions, weakened albedo feedback, and relatively small oceanic heat flux in the north.

Similar on the Inside (pre-grinding)

NASA Technical Reports Server (NTRS)

2004-01-01

This approximate true-color image taken by the panoramic camera on the Mars Exploration Rover Opportunity show the rock called 'Pilbara' located in the small crater dubbed 'Fram.' The rock appears to be dotted with the same 'blueberries,' or spherules, found at 'Eagle Crater.' Spirit drilled into this rock with its rock abrasion tool. After analyzing the hole with the rover's scientific instruments, scientists concluded that Pilbara has a similar chemical make-up, and thus watery past, to rocks studied at Eagle Crater. This image was taken with the panoramic camera's 480-, 530- and 600-nanometer filters.

Similar on the Inside (post-grinding)

NASA Technical Reports Server (NTRS)

2004-01-01

This approximate true-color image taken by the panoramic camera on the Mars Exploration Rover Opportunity show the hole drilled into the rock called 'Pilbara,' which is located in the small crater dubbed 'Fram.' Spirit drilled into this rock with its rock abrasion tool. The rock appears to be dotted with the same 'blueberries,' or spherules, found at 'Eagle Crater.' After analyzing the hole with the rover's scientific instruments, scientists concluded that Pilbara has a similar chemical make-up, and thus watery past, to rocks studied at Eagle Crater. This image was taken with the panoramic camera's 480-, 530- and 600-nanometer filters.

Annual Report on the Activities and Publications of the DHS-DNDO-NTNFC Sponsored Post-doctoral Fellow at Los Alamos National Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rim, Jung Ho; Tandon, Lav

This report is a summary of the projects Jung Rim is working on as a DHS postdoctoral fellow at Los Alamos National Laboratory. These research projects are designed to explore different radioanalytical methods to support nuclear forensics applications. The current projects discussed here include development of alpha spectroscopy method for 240/239Pu Isotopic ratio measurement, non-destructive uranium assay method using gamma spectroscopy, and 236U non-destructive uranium analysis using FRAM code. This report documents the work that has been performed since the start of the postdoctoral appointment.

MIZEX: A Program for Mesoscale Air-Ice-Ocean Interaction Experiments in Arctic Marginal Ice Zones. VIII. A Science Plan for a Winter Marginal Ice Zone Experiment in the Fram Strait/Greenland Sea: 1987/89,

DTIC Science & Technology

1986-04-01

forward modeling, with the pa- be telemetered via the ARGOS system for real - rameter changes needed to bring the predictions time evaluation, and the...integrated en ’i- rtinnental measurement svs fern. quisition system to the Winter MIZEX in I-ram To control and direct the experiment, real - time Strait...to measure, under- Electromagnetic sensing via aircraft and satellites stand, and model: will be employed in real time to identify eddy " Changes in

Impact of Greenland orography on the Atlantic Meridional Overturning Circulation

NASA Astrophysics Data System (ADS)

Davini, P.; Hardenberg, J.; Filippi, L.; Provenzale, A.

2015-02-01

We show that the absence of the Greenland ice sheet would have important consequences on the North Atlantic Ocean circulation, even without taking into account the effect of the freshwater input to the ocean from ice melting. These effects are investigated in a 600year long coupled ocean-atmosphere simulation with the high-resolution global climate model EC-Earth 3.0.1. Once a new equilibrium is established, a cooling of Eurasia and of the North Atlantic and a poleward shift of the subtropical jet are observed. These hemispheric changes are ascribed to a weakening of the Atlantic Meridional Overturning Circulation (AMOC) by about 12%. We attribute this slowdown to a reduction in salinity of the Arctic basin and to the related change of the mass and salt transport through the Fram Strait—a consequence of the new surface wind pattern over the lower orography. This idealized experiment illustrates the sensitivity of the AMOC to local surface winds.

Fluid-Evaporation Records Preserved in Meridiani Rocks

NASA Technical Reports Server (NTRS)

Rao, M. N.; Nyquist, Laurence E.; Sutton, S. R.

2009-01-01

We have shown earlier that the high SO3/Cl ratios found in secondary mineral assemblages in shergottite GRIM glasses (Gas-Rich Impact-Melt) likely resulted from interactions of regolith materials with sulfate-rich (and Cl-poor) solutions. The low SO3/Cl ratios determined in secondary salts in nakhalite fracture-fillings presumably formed by rock interactions with chloride-rich (and SO4-poor) solutions near Mars surface. The SO3 and Cl abundances determined by APXS in abraded rocks (RAT) from Endurance, Fram and Eagle craters indicate that these salt assemblages likely formed by evaporative concentration of brine fluids at Meridiani. The SO3/Cl ratios in the abraded rocks are examined here, instead of their absolute abundances, because the abundance ratios might provide better guide-lines for tracking the evolution of evaporating fluids at Meridiani. The SO3/Cl ratios in these samples, in turn, might provide clues for the mobile element ratios of the altering fluids that infiltrated into the Meridiani rocks.

The Last Interglacial Labrador Sea: A Pervasive Millennial Oscillation In Surface Water Conditions Without Labrador Sea Water Formation

NASA Astrophysics Data System (ADS)

Hillaire-Marcel, C.; de Vernal, A.

A multi-proxy approach was developed to document secular to millenial changes of potential density in surface, mesopelagic, and bottom waters of the Labrador Sea, thus allowing to reconstruct situations when winter convection with intermediate or deep water formation occurred in the basin. This approach relies on dinocyst-transfer functions providing estimates of sea-surface temperature and salinity that are used to calibrate past-relationships between oxygen 18 contents in calcite and potential density gradients. The oxygen isotope compositions of epipelagic (Globigerina bul- loides), deeper-dwelling (Neogloboquadrina pachyderma, left coiling), and benthic (Uvigerina peregrina and Cibicides wuellerstorfi) foraminifera, then allow to extrap- olate density gradients between the corresponding water layers. This approach has been tested in surface sediments in reference to modern hydrographic conditions at several sites from the NW North Atlantic, then used to reconstruct past conditions from high resolution studies of cores raised from the southern Greenland Rise (off Cape Farewell). Results indicate that the modern-like regime established during the early Holocene and full developed after 7 ka only. It is marked by weak density gradi- ents between the surface and intermediate water masses, allowing winter convection down to a lower pycnocline between intermediate and deep-water masses, thus the formation of intermediate Labrador Sea Water (LSW). Contrasting with the middle to late Holocene situation, since the last interglacial and throughout the last climatic cycle, a single and dense water mass seems to have occupied the water column below a generally low-density surface water layer, thus preventing deep convection. There- fore, the production of LSW seems to be feature specific to the present interglacial interval that could soon cease to exist, due to global warming, as suggested by recent ocean model experiments and by the fact that it never occurred during the last inter- glacial. We think that the mechanism for the eventual shut-down in LSW formation involves an enhanced freshwater export from the Arctic into the Labrador Sea, as a consequence of both an enhanced hydrological cycle in a warmer mean climate, and a lesser sea-ice extend in the Canadian Arctic Archipelago. Both the last interglacial and the Holocene depict large amplitude millenial oscillations in surface water conditions and in density gradients with the underlying water mass. During the last 11 ka, six 1 of these oscillations are recorded, and those that occurred since ca. 7 ka BP probably resulted in large amplitude changes in LSW-production rate. These oscillations pos- sibly correspond to the Holocene "pervasive millennial cycle" observed by Bond and others in a few North Atlantic records. We hypothesize that they are related to sea ice conditions in the Arctic Ocean and to the relative routing of outflowing freshwaters through either the Canadian Arctic Archipelago or Fram Strait, into the North Atlantic. These oscillations would probably maintain after an eventual collapse of LSW forma- tion, as suggested by the last interglacial reconstructions, but their impact on future thermohaline circulation in the North Atlantic is unclear. 2

Storm-driven Mixing and Potential Impact on the Arctic Ocean

NASA Technical Reports Server (NTRS)

Yang, Jiayan; Comiso, Josefino; Walsh, David; Krishfield, Richard; Honjo, Susumu; Koblinsky, Chester J. (Technical Monitor)

2001-01-01

Observations of the ocean, atmosphere, and ice made by Ice-Ocean Environmental Buoys (IOEBs) indicate that mixing events reaching the depth of the halocline have occurred in various regions in the Arctic Ocean. Our analysis suggests that these mixing events were mechanically forced by intense storms moving across the buoy sites. In this study, we analyzed these mixing events in the context of storm developments that occurred in the Beaufort Sea and in the general area just north of Fram Strait, two areas with quite different hydrographic structures. The Beaufort Sea is strongly influenced by inflow of Pacific water through Bering Strait, while the area north of Fram Strait is directly affected by the inflow of warm and salty North Atlantic water. Our analyses of the basin-wide evolution of the surface pressure and geostrophic wind fields indicate that the characteristics of the storms could be very different. The buoy-observed mixing occurred only in the spring and winter seasons when the stratification was relatively weak. This indicates the importance of stratification, although the mixing itself was mechanically driven. We also analyze the distribution of storms, both the long-term climatology as well as the patterns for each year in the last two decades. The frequency of storms is also shown to be correlated- (but not strongly) to Arctic Oscillation indices. This study indicates that the formation of new ice that leads to brine rejection is unlikely the mechanism that results in the type of mixing that could overturn the halocline. On the other hand, synoptic-scale storms can force mixing deep enough to the halocline and thermocline layer. Despite a very stable stratification associated with the Arctic halocline, the warm subsurface thermocline water is not always insulated from the mixed layer.

A 26 million year gap in the central Arctic record at the greenhouse-icehouse transition: Looking for clues

USGS Publications Warehouse

Sangiorgi, Francesca; Brumsack, Hans-Juergen; Willard, Debra A.; Schouten, Stefan; Stickley, Catherine E.; O'Regan, Matthew; Reichart, Gert-Jan; Damste, Jaap S. Sinninghe; Brinkhuis, Henk

2008-01-01

The Cenozoic record of the Lomonosov Ridge (central Arctic Ocean) recovered during Integrated Ocean Drilling Program (IODP) Expedition 302 revealed an unexpected 26 Ma hiatus, separating middle Eocene (∼44.4 Ma) from lower Miocene sediments (∼18.2 Ma). To elucidate the nature of this unconformity, we performed a multiproxy palynological (dinoflagellate cysts, pollen, and spores), micropaleontological (siliceous microfossils), inorganic, and organic (Tetra Ether Index of lipids with 86 carbon atoms (TEX86) and Branched and Isoprenoid Tetraether (BIT)) geochemical analysis of the sediments from ∼5 m below to ∼7 m above the hiatus. Four main paleoenvironmental phases (A–D) are recognized in the sediments encompassing the unconformity, two below (A–B) and two above (C–D): (A) Below the hiatus, proxies show relatively warm temperatures, with Sea Surface Temperatures (TEX86‐derived SSTs) of about 8°C and high fresh to brackish water influence. (B) Approaching the hiatus, proxies indicate a cooling trend (TEX86‐derived SSTs of ∼5°C), increased freshwater influence, and progressive shoaling of the Lomonosov Ridge drilling site, located close to or at sea level. (C) The interval directly above the unconformity contains sparse reworked Cretaceous to Oligocene dinoflagellate cysts. Sediments were deposited in a relatively shallow, restricted marine environment. Proxies show the simultaneous influence of both fresh and marine waters, with alternating oxic and anoxic conditions. Pollen indicates a relatively cold climate. Intriguingly, TEX86‐derived SSTs are unexpectedly high, ∼15–19°C. Such warm surface waters may be partially explained by the ingression of warmer North Atlantic waters after the opening of the Fram Strait during the early Miocene. (D) Sediments of the uppermost interval indicate a phase of extreme oxic conditions, and a well‐ventilated environment, which occurred after the complete opening of the Fram Strait. Importantly, and in contrast with classical postrifting thermal subsidence models for passive margins, our data suggest that sediment erosion and/or nondeposition that generated the hiatus was likely due to a progressive shoaling of the Lomonosov Ridge. A shallow water setting both before and after the hiatus suggests that the Lomonosov Ridge remained at or near sea level for the duration of the gap in the sedimentary record. Interacting sea level changes and/or tectonic activity (possibly uplift) must be invoked as possible causes for such a long hiatus.

Arctic Ocean Pathways in the 21st century

NASA Astrophysics Data System (ADS)

Aksenov, Yevgeny; van Gennip, Simon J.; Kelly, Stephen J.; Popova, Ekaterina E.; Yool, Andrew

2017-04-01

In the last three decades, changes in the Arctic environment have been occurring at an increasing rate. The opening up of large areas of previously sea ice-covered ocean affects the marine environment with potential impacts on Arctic ecosystems, including through changes in Arctic access, industries and societies. Changes to sea ice and surface winds result in large-scale shifts in ocean circulation and oceanic pathways. This study presents a high-resolution analysis of the projected ocean circulation and pathways of the Arctic water masses across the 21st century. The analysis is based on an eddy-permitting high-resolution global simulation of the ocean general circulation model NEMO (Nucleus for European Modelling of the Ocean) at the 1/4-degree horizontal resolution. The atmospheric forcing is from HadGEM2-ES model output from IPCC Assessment Report 5 (AR5) simulations performed for Coupled Model Intercomparison Project 5 (CMIP5), and follow the Representative Concentration Pathway 8.5 (RCP8.5) scenario. During the 21st century the AO experiences a significant warming, with sea surface temperature increased by in excess of 4 deg. C. Annual mean Arctic sea ice thickness drops to less than 0.5m, and the Arctic Ocean is ice-free in summer from the mid-century. We use an off-line tracer technique to investigate Arctic pathways of the Atlantic and Pacific waters (AW and PW respectively) under this future climate. The AW tracers have been released in the eastern Fram Strait and in the western Barents Sea, whereas the PW tracer has been seeded in the Bering Strait. In the second half of the century the upper 1000 m ocean circulation shows a reduction in the eastward AW flow along the continental slopes towards the Makarov and Canada basins and a deviation of the PW flow away from the Beaufort Sea towards the Siberian coast. Strengthening of Arctic boundary current and intensification of the cyclonic gyre in the Nansen basin of the Arctic Ocean is accompanied by weakening of the current and an anti-cyclonic gyre spin-up in the Makarov Basin. This presents a shift of the Arctic circulation "dipole" and of the Transpolar Drift, with the consequence that the PW flow towards Fram Strait is significantly reduced by the end of the century, weakening the Pacific-Atlantic connection via the Arctic Ocean, and reducing the Arctic freshwater outflow into the North Atlantic. Examination of the simulations suggests that these circulation changes are primarily due to the shift in the wind.

The not-so-silent world: Measuring Arctic, Equatorial, and Antarctic soundscapes in the Atlantic Ocean

NASA Astrophysics Data System (ADS)

Haver, Samara M.; Klinck, Holger; Nieukirk, Sharon L.; Matsumoto, Haru; Dziak, Robert P.; Miksis-Olds, Jennifer L.

2017-04-01

Anthropogenic noise in the ocean has been shown, under certain conditions, to influence the behavior and health of marine mammals. Noise from human activities may interfere with the low-frequency acoustic communication of many Mysticete species, including blue (Balaenoptera musculus) and fin whales (B. physalus). This study analyzed three soundscapes in the Atlantic Ocean, from the Arctic to the Antarctic, to document ambient sound. For 16 months beginning in August 2009, acoustic data (15-100 Hz) were collected in the Fram Strait (79°N, 5.5°E), near Ascension Island (8°S, 14.4°W) and in the Bransfield Strait (62°S, 55.5°W). Results indicate (1) the highest overall sound levels were measured in the equatorial Atlantic, in association with high levels of seismic oil and gas exploration, (2) compared to the tropics, ambient sound levels in polar regions are more seasonally variable, and (3) individual elements beget the seasonal and annual variability of ambient sound levels in high latitudes. Understanding how the variability of natural and man-made contributors to sound may elicit differences in ocean soundscapes is essential to developing strategies to manage and conserve marine ecosystems and animals.

Arctic Sea Ice Export Through Fram Strait and Atmospheric Planetary Waves

NASA Technical Reports Server (NTRS)

Cavalieri, Donald J.; Koblinsky, Chester (Technical Monitor)

2001-01-01

A link is found between the variability of Arctic sea ice export through Ram Strait and the phase of the longest atmospheric planetary wave (zonal wave 1) in SLP for the period 1958-1997. Previous studies have identified a link between From Strait ice export and the North Atlantic Oscillation (NAO), but this link has been described as unstable because of a lack of consistency over time scales longer than the last two decades. Inconsistent and low correlations are also found between From Strait ice export and the Arctic Oscillation (AD) index. This paper shows that the phase of zonal wave 1 explains 60% - 70% of the simulated From Strait ice export variance over the Goodyear period 1958 - 1997. Unlike the NAB and AD links, these high variances are consistent for both the first and second halves of the Goodyear period. This consistency is attributed to the sensitivity of the wave I phase at high latitudes to the presence of secondary low pressure systems in the Barents Sea that serve to drive sea ice southward through From Strait. These results provide further evidence that the phase of zonal wave 1 in SLP at high latitudes drives regional as well as hemispheric low frequency Arctic Ocean and sea ice variability.

China Macroeconomic: Documentation Data Banks. Volume 3. Foreign Trade.

DTIC Science & Technology

1984-11-15

1983 data from Chlnese "Cmtan, Statistics," Econmic Infomation and Agency, THoE ong Pr ious years from CIA "International Trade Statistics" Load fram...204,097 145,564 515,062 1984 N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A 6 Sources, see below 19F, 1983 data from Chinese "Customs Statistics," Econmic ...Statistics," EconmIc Information and Agency, F org Previous years fran CIA "Internationl Trade Statistics" Load from rw 12 to row 54 -.96 - A B C D E F G H

Fridtjof Nansen - Scientist, Diplomat and Humanist

NASA Astrophysics Data System (ADS)

Gjelsvik, Tore

In my opinion, no Norwegian has made a deeper impression upon his contemporaries than Fridtjof Nansen. Even today, more than 60 years after he passed away, young people who want to make an extraordinary physical effort talk about walking in his footsteps - or skiing in his ski tracks. References to Nansen's humanitarian efforts after the first world war can be read almost daily in Norwegian newspapers in articles discussing aid to refugees, starving populations or ethnic minorities threatened with extermination. More than 200,000 people, many of them foreigners, visit Nansen's famous polar ship FRAM, housed on the peninsula Bygdøy, on the outskirt of Oslo.

Carbon flows in the benthic food web at the deep-sea observatory HAUSGARTEN (Fram Strait)

NASA Astrophysics Data System (ADS)

van Oevelen, Dick; Bergmann, Melanie; Soetaert, Karline; Bauerfeind, Eduard; Hasemann, Christiane; Klages, Michael; Schewe, Ingo; Soltwedel, Thomas; Budaeva, Nataliya E.

2011-11-01

The HAUSGARTEN observatory is located in the eastern Fram Strait (Arctic Ocean) and used as long-term monitoring site to follow changes in the Arctic benthic ecosystem. Linear inverse modelling was applied to decipher carbon flows among the compartments of the benthic food web at the central HAUSGARTEN station (2500 m) based on an empirical data set consisting of data on biomass, prokaryote production, total carbon deposition and community respiration. The model resolved 99 carbon flows among 4 abiotic and 10 biotic compartments, ranging from prokaryotes up to megafauna. Total carbon input was 3.78±0.31 mmol C m -2 d -1, which is a comparatively small fraction of total primary production in the area. The community respiration of 3.26±0.20 mmol C m -2 d -1 is dominated by prokaryotes (93%) and has lower contributions from surface-deposit feeding macro- (1.7%) and suspension feeding megafauna (1.9%), whereas contributions from nematode and other macro- and megabenthic compartments were limited to <1%. The high prokaryotic contribution to carbon processing suggests that functioning of the benthic food web at the central HAUSGARTEN station is comparable to abyssal plain sediments that are characterised by strong energy limitation. Faunal diet compositions suggest that labile detritus is important for deposit-feeding nematodes (24% of their diet) and surface-deposit feeding macrofauna (˜44%), but that semi-labile detritus is more important in the diets of deposit-feeding macro- and megafauna. Dependency indices on these food sources were also calculated as these integrate direct (i.e. direct grazing and predator-prey interactions) and indirect (i.e. longer loops in the food web) pathways in the food web. Projected sea-ice retreats for the Arctic Ocean typically anticipate a decrease in the labile detritus flux to the already food-limited benthic food web. The dependency indices indicate that faunal compartments depend similarly on labile and semi-labile detritus, which suggests that the benthic biota may be more sensitive to changes in labile detritus inputs than when assessed from diet composition alone. Species-specific responses to different types of labile detritus inputs, e.g. pelagic algae versus sympagic algae, however, are presently unknown and are needed to assess the vulnerability of individual components of the benthic food web.

Helicopter- and ship-based measurements of mesoscale ocean color and thermal features in the marginal ice zone

NASA Astrophysics Data System (ADS)

Tanis, Fred J.; Manley, Thomas O.; Mitchell, Brian G.

1990-09-01

Eddies along the Polar Front/Marginal Ice Zone (MIZ) in Fram Strait are thought to make important contributions to nutrient flux and stimulation of primary productivity. During the Coordinated Eastern Arctic Regional Experiment (CEAREX) helicopter-based measurements of upwelling radiance were made in four visible spectral bands and in the thermal IR across mesoscale features associated with the MIZ. These structures were mapped by flying a grid pattern over the ocean surface to define eddy boundaries. Subsequently, the area was also sampled vertically with CTD and spectral radiometer profilers. Data obtained from a single structure were integrated to construct a three dimensional picture of physical and optical properties. Volume modeling of temperature, salinity, and density fields obtained from CTD survey define the subsurface eddy structure and are in good agreement with infrared derived characteristics. Maximum temperature in the core was found to be four degrees higher than the surrounding water. Volume modeling further indicates that a subsurface layer of Arctic Intermediate Water is intrinsically associated with the surface expression of the eddy. The ratio of upwelling radiances, L(44l)/L(565), was found to be correlated to surface chlorophyll, particulate absorption coefficient, and in water determinations of L using the optical profiling system. The remote sensing reflectance ratio along with the IR sea surface temperature were found to be useful to detect the surface expression of the eddy and to indicate near surface biological and physical processes.

Inter-annual variability of transparent exopolymer particles in the Arctic Ocean reveals high sensitivity to ecosystem changes.

PubMed

Engel, Anja; Piontek, Judith; Metfies, Katja; Endres, Sonja; Sprong, Pim; Peeken, Ilka; Gäbler-Schwarz, Steffi; Nöthig, Eva-Maria

2017-06-23

Transparent exopolymer particles (TEP) are a class of marine gel particles and important links between surface ocean biology and atmospheric processes. Derived from marine microorganisms, these particles can facilitate the biological pumping of carbon dioxide to the deep sea, or act as cloud condensation and ice nucleation particles in the atmosphere. Yet, environmental controls on TEP abundance in the ocean are poorly known. Here, we investigated some of these controls during the first multiyear time-series on TEP abundance for the Fram Strait, the Atlantic gateway to the Central Arctic Ocean. Data collected at the Long-Term Ecological Research observatory HAUSGARTEN during 2009 to 2014 indicate a strong biological control with highest abundance co-occurring with the prymnesiophyte Phaeocystis pouchetii. Higher occurrence of P. pouchetii in the Arctic Ocean has previously been related to northward advection of warmer Atlantic waters, which is expected to increase in the future. Our study highlights the role of plankton key species in driving climate relevant processes; thus, changes in plankton distribution need to be accounted for when estimating the ocean's biogeochemical response to global change.

Generation of Volatile Organic Compounds from Dissolved Organic Matter in far North Atlantic Surface Ocean Waters.

NASA Astrophysics Data System (ADS)

Hudson, E. D.; Ariya, P. A.

2005-12-01

The photochemical degradation of dissolved organic matter (DOM) in surface ocean waters is thought to be a source of volatile organic compounds (VOC) (including non-methane hydrocarbons and low MW carbonyl compounds) to the remote marine troposphere. We report on the characterization of DOM sampled at over 30 sites in the far North Atlantic (Greenland and Norwegian seas, Fram strait) during the summer of 2004, and on experiments to identify factors responsible for the photochemical generation of VOCs in these samples. The results will be discussed in the context of VOC profiles of whole air samples taken to match the seawater samples in time and space.

Opportunity's Travels During its First 205 Martian Days

NASA Technical Reports Server (NTRS)

2004-01-01

This map shows the traverse of NASA's Mars Exploration Rover Opportunity through the rover's 205th martian day, or sol (Aug. 21, 2004). The background image is from the rover's descent imaging camera. Images inset along the route are from Opportunity's navigation camera. Opportunity began its exploration inside 'Eagle' crater near the left edge of the map. Following completion of its study of the outcrop there, it traversed eastward to a small crater ('Fram' crater) before driving southeastward to the rim of 'Endurance' crater. After a survey partly around the south rim of Endurance crater, Opportunity drove inside the southwest rim of Endurance crater and began a systematic study of outcrops exposed on the crater's inner slope.

Continued Development and Implementation of the Universal Network Interface Device (UNID) II in the Digital Engineering Laboratory Network (DELNET). Volume 2.

DTIC Science & Technology

1984-12-01

PACKET LO-ATED IN TABLE LCNTTB. INPUT < THE INDUT IS A TWO CHARACTER ASCII VALUE INDICATING THE TABLE REQUIRING EVALUATION . > PROCESSING THIS PROCEDURE...INTO OHANYE A (2). I NPUT THE INPUT IS AN INTEGER VA UE INDICATING’ THE TAlN’LE LOCATI’ OF THE FRAmE TO BE EVALUATED . PROC--SSING THIS PROCEDURE LOU-S AT...GOOD AEXICdLFCL ~N IS NuT rC:L I VED LY THE END OF THE WAIT PER ICOH, I r I S fx>Sit-..) ACAI N UPION IriL NE.XT CflLL THRJOH THIS IRROCEDURE. A [ RAMC OF

Remote sensing of the marginal ice zone during Marginal Ice Zone Experiment (MIZEX) 83

NASA Technical Reports Server (NTRS)

Shuchman, R. A.; Campbell, W. J.; Burns, B. A.; Ellingsen, E.; Farrelly, B. A.; Gloersen, P.; Grenfell, T. C.; Hollinger, J.; Horn, D.; Johannessen, J. A.

1984-01-01

The remote sensing techniques utilized in the Marginal Ice Zone Experiment (MIZEX) to study the physical characteristics and geophysical processes of the Fram Strait Region of the Greenland Sea are described. The studies, which utilized satellites, aircraft, helicopters, and ship and ground-based remote sensors, focused on the use of microwave remote sensors. Results indicate that remote sensors can provide marginal ice zone characteristics which include ice edge and ice boundary locations, ice types and concentration, ice deformation, ice kinematics, gravity waves and swell (in the water and the ice), location of internal wave fields, location of eddies and current boundaries, surface currents and sea surface winds.

Reconstruction of sea-ice cover and primary production on the East Greenland Shelf (73°N) during the last 5200 years

NASA Astrophysics Data System (ADS)

Kolling, Henriette Marie; Stein, Rüdiger; Fahl, Kirsten; Perner, Kerstin; Moros, Matthias

2016-04-01

Over the last decades the extent and thickness of Arctic sea ice has changed dramatically and much more rapidly than predicted by climate models. Thus, high-resolution sea-ice reconstructions from pre-anthropogenic times are useful and needed in order to better understand the processes controlling the natural sea-ice variability. Here, we present the first high-resolution biomarker (IP25, sterols) approach over the last 5.2 ka from the East Greenland Shelf (for background about the biomarker approach see Belt et al., 2007; Müller et al., 2009, 2011). This area is highly sensitive to sea-ice changes, as it underlies the pathway of the East Greenland Current, the main exporter of Arctic freshwater and sea ice that affects the environmental conditions on the East Greenland Shelf and deep-water formation/ convection in the Northern North Atlantic. After rather stable sea-ice conditions in the mid-Holocene we found a strong increase in sea ice, cumulating around 1.5 ka and associated with the Neoglacial cooling. The general trend especially during the last 1ka is interrupted by several short-lived events such as the prominent Medieval Warm Period and Little Ice Age, characterized by minimum and maximum sea-ice extent, respectively. Using a spectral analysis, we could identify several cyclicites, e.g. a 45-year cyclicity for cold events. A comparison to similar records from the eastern Fram Strait revealed a slight time lag in the onset of the Neoglacial, but also suggesting the direct link of the East Greenland Shelf area to the Arctic sea-ice/freahwater outflow. A comparison of the biomarker data with a new foraminiferal record obtained from the same site (Perner et al., 2015) suggests that IP25 and foraminifera assemblages are probably controlled by rather different processes within the oceanographic systems, such as the sea-ice conditions and, for the foraminifera, water-mass changes and nutrient supply. References: Belt. S.T., Massé, G., Rowland, S.J., Poulin, M., Michel, C., LeBlanc B., 2007. A novel chemical fossil of palaeo sea ice: IP25. Organic Geochemistry 38 (2007) 16-27 Müller, J., Massé, G., Stein, R., Belt, S.T., 2009. Variability of sea-ice conditons in the Fram Strait over the past 30,000 years. Nature Geoscience Vol 2 (2009), 772-776 Müller, J., Wagner, A., Fahl, K., Stein, R., Prange, M., Lohmann, G., 2011. Towards quantitative sea ice reconstructions in the northern North Atlantic: A combines biomarker and numerical modelling approach. East and Planetrary Science Letters 306 (2011) 137-148 Perner, K., Moros, M., Lloyd, J.M., Jansen, E., Stein, R., 2015. Mid to late Holocene strengthening of the East Greenland Current linked to warm subsurface Atlantic water. Quaternary Science Reviews 129 (2015) 296-307

Picoeukaryote plankton composition off West Spitsbergen at the entrance to the Arctic Ocean.

PubMed

Kilias, Estelle S; Nöthig, Eva-Maria; Wolf, Christian; Metfies, Katja

2014-01-01

Investigation of marine eukaryotic picoplankton composition is limited by missing morphological features for appropriate identification. Consequently, molecular methods are required. In this study, we used 454-pyrosequencing to study picoplankton communities at four stations in the West Spitsbergen Current (WSC; Fram Strait). High abundances of Micromonas pusilla were detected in the station situated closest to Spitsbergen, as seen in surveys of picoplankton assemblages in the Beaufort Sea. At the other three stations, other phylotypes, affiliating with Phaeocystis pouchetii and Syndiniales in the phylogenetic tree, were present in high numbers, dominating most of them. The picoplankton community structures at three of the stations, all with similar salinity and temperature, were alike. At the fourth station, the influence of the East Spitsbergen Current, transporting cold water from the Barents Sea around Spitsbergen, causes different abiotic parameters that result in a significantly different picoeukaryote community composition, which is dominated by M. pusilla. This observation is particularly interesting with regard to ongoing environmental changes in the Arctic. Ongoing warming of the WSC could convey a new picoplankton assemblage into the Arctic Ocean, which may come to affect the dominance of M. pusilla. © 2014 The Author(s) Journal of Eukaryotic Microbiology © 2014 International Society of Protistologists.

Baroclinic stabilization effect of the Atlantic-Arctic water exchange simulated by the eddy-permitting ocean model and global atmosphere-ocean model

NASA Astrophysics Data System (ADS)

Moshonkin, Sergey; Bagno, Alexey; Gritsun, Andrey; Gusev, Anatoly

2017-04-01

Numerical experiments were performed with the global atmosphere-ocean model INMCM5 (for version of the international project CMIP6, resolution for atmosphere is 2°x1.5°, 21 level) and with the three-dimensional, free surface, sigma coordinate eddy-permitting ocean circulation model for Atlantic (from 30°S) - Arctic and Bering sea domain (0.25 degrees resolution, Institute of Numerical Mathematics Ocean Model or INMOM). Spatial resolution of the INMCM5 oceanic component is 0.5°x0.25°. Both models have 40 s-levels in ocean. Previously, the simulations were carried out for INMCM5 to generate climatic system stable state. Then model was run for 180 years. In the experiment with INMOM, CORE-II data for 1948-2009 were used. As the goal for comparing results of two these numerical models, we selected evolution of the density and velocity anomalies in the 0-300m active ocean layer near Fram Strait in the Greenland Sea, where oceanic cyclonic circulation influences Atlantic-Arctic water exchange. Anomalies were count without climatic seasonal cycle for time scales smaller than 30 years. We use Singular Value Decomposition analysis (SVD) for density-velocity anomalies with time lag from minus one to six months. Both models perform identical stable physical result. They reveal that changes of heat and salt transports by West Spitsbergen and East Greenland currents, caused by atmospheric forcing, produce the baroclinic modes of velocity anomalies in 0-300m layer, thereby stabilizing ocean response on the atmospheric forcing, which stimulates keeping water exchange between the North Atlantic and Arctic Ocean at the certain climatological level. The first SVD-mode of density-velocity anomalies is responsible for the cyclonic circulation variability. The second and third SVD-modes stabilize existing ocean circulation by the anticyclonic vorticity generation. The second and third SVD-modes give 35% of the input to the total dispersion of density anomalies and 16-18% of the input to the total dispersion of velocity anomalies for numerical results as in INMCM5 so in INMOM models. Input to the total dispersion of velocity anomalies for the first SVD-mode is equal to 50% for INMCM5 and only 19% for INMOM. The research was done in the INM RAS. The model INMOM was supported by Russian Foundation for Basic Research (grant №16-05-00534), and the model INMCM was supported by the Russian Scientific Foundation (grant №14-27-00126).

The Life-Cycle of a Polar Low Observed with Research Aircraft Dropsondes

NASA Astrophysics Data System (ADS)

Saetra, O.; Linders, T.

2008-12-01

The structure and life cycle of a polar low that formed over the ocean south of the Fram Strait on 3 and 4 March 2008 is described using GPS dropsondes from the DLR Falcon research aircraft and by AVHRR satellite images. Data from three successive flights during the life cycle of the polar low will be presented. The Norwegian IPY-THORPEX project carried out a field experiment between February and May 2008, aiming at investigating adverse weather in the Arctic. During the campaign period, the DLR Falcon aircraft was stationed at Andoya Airport in Northern Norway. On the evening 2 March the synoptic scale flow triggered a cold-air outbreak in the Fram Strait and the western Barents Sea. The weather analysis from the Norwegian weather service (met.no)indicated strong reversed shear flow (warm air to the left) and favorable conditions for the formations of polar lows. A flight for the next morning was planned. At the time of departure AVHRR satellite images of deep-convective clouds revealed the presence of an Arctic front in the northerly winds between Greenland and the Svalbard islands. During this flight 18 dropsondes were successfully released. A second flight was carried out later the same day, 3 March. At this time a meso-scale cyclone had formed at the southern tip of the Arctic Front. The cyclone was measured in three cross-sections with 14 successful sondes released. The night between 3 and 4 March the cyclone intensified and by the third flight a mature polar low was located outside the coast of Trondelag in Norway. The last flight was carried out, staring on the morning 4 March, making 4 cross-sections with 20 dropsondes. On the evening 4 March, shortly after the third flight, the polar low made landfall and faded rapidly.

Exploring Science Through Polar Exploration

NASA Astrophysics Data System (ADS)

Pfirman, S. L.; Bell, R. E.; Zadoff, L.; Kelsey, R.

2003-12-01

Exploring the Poles is a First Year Seminar course taught at Barnard College, Columbia University. First Year Seminars are required of incoming students and are designed to encourage critical analysis in a small class setting with focused discussion. The class links historical polar exploration with current research in order to: introduce non-scientists to the value of environmental science through polar literature; discuss issues related to venturing into the unknown that are of relevance to any discipline: self-reliance, leadership, preparation, decisions under uncertainty; show students the human face of science; change attitudes about science and scientists; use data to engage students in exploring/understanding the environment and help them learn to draw conclusions from data; integrate research and education. These goals are met by bringing analysis of early exploration efforts together with a modern understanding of the polar environment. To date to class has followed the efforts of Nansen in the Fram, Scott and Amundsen in their race to the pole, and Shackleton's Endurance. As students read turn-of-the-century expedition journals, expedition progress is progressively revealed on an interactive map showing the environmental context. To bring the exploration process to life, students are assigned to expedition teams for specific years and the fates of the student "expeditions" are based on their own decisions. For example, in the Arctic, they navigate coastal sea ice and become frozen into the ice north of Siberia, re-creating Nansen's polar drift. Fates of the teams varied tremendously: some safely emerged at Fram Strait in 4 years, while others nearly became hopelessly lost in the Beaufort Gyre. Students thus learn about variability in the current polar environment through first hand experience, enabling them to appreciate the experiences, decisions, and, in some cases, the luck, of polar explorers. Evaluation by the Columbia Center for New Media, Teaching and Learning shows that combining historical texts with current data/simulations is an extremely powerful way of engaging non-scientists in science, and explaining the role of science and the environment in decision-making.

Bottom melting of Arctic Sea Ice in the Nansen Basin due to Atlantic Water influence

NASA Astrophysics Data System (ADS)

Muilwijk, Morven; Smedsrud, Lars H.; Meyer, Amelie

2016-04-01

Our global climate is warming, and a shrinking Arctic sea ice cover remains one of the most visible signs of this warming. Sea Ice loss is now visible for all months in all regions of the Arctic. Hydrographic and current observations from a region north of Svalbard collected during the Norwegian Young Sea Ice Cruise (N-ICE2015) are presented here. Comparison with historical data shows that the new observations from January through June fill major gaps in available observations, and help describing important processes linking changes in regional Atlantic Water (AW) heat transport and sea ice. Warm and salty AW originating in the North Atlantic enters the Arctic Ocean through the Fram Strait and is present below the Arctic Sea Ice cover throughout the Arctic. However, the depth of AW varies by region and over time. In the region north of Svalbard, we assume that depth could be governed primarily by local processes, by upstream conditions of the ice cover (Northwards), or by upstream conditions of the AW (Southwards). AW carries heat corresponding to the volume transport of approximately 9 SV through Fram Strait, varying seasonally from 28 TW in winter to 46 TW in summer. Some heat is recirculated, but the net annual heat flux into the Arctic Ocean from AW is estimated to be around 40 TW. The Atlantic Water layer temperature at intermediate depths (150-900m) has increased in recent years. Until recently, maximum temperatures have been found to be 2-3 C in the Nansen Basin. Studies have shown that for example, in the West Spitsbergen Current the upper 50-200m shows an overall AW warming of 1.1 C since 1979. In general we expect efficient melting when AW is close to the surface. Previously the AW entering through Fram Strait has been considered as less important because changes in the sea ice cover have been connected to greater inflow of Pacific Water through Bering Strait and atmospheric forcing. Conversely it is now suggested that AW has direct impact on melting of sea ice. Because of the large increase in AW temperature over the last 30 years we assume that perturbations in the AW are important drivers of location of AW in this region, and that the sea ice and polar water above is passively responding to the AW variability. Previously it has been argued that the warming of AW could not contribute to increased ice melting because of the strong stratification. Our observations show an ice cover around 2 m, but with active ice formation in between the larger and thicker floes. The ongoing freezing drives brine release and subsequent convection, contributing to the deep ~100 m mixed layer observed in the area until mid-May. Onwards from May solar heating is stratifying the upper layer by adding heat. Data analysis is ongoing but indicates that location of AW is an important factor in bottom melting in the area north of Svalbard. Location of AW and related bottom melting will be evaluated using simulations from a fully coupled climate model.

Cascading off the West Greenland Shelf: A numerical perspective

NASA Astrophysics Data System (ADS)

Marson, Juliana M.; Myers, Paul G.; Hu, Xianmin; Petrie, Brian; Azetsu-Scott, Kumiko; Lee, Craig M.

2017-07-01

Cascading of dense water from the shelf to deeper layers of the adjacent ocean basin has been observed in several locations around the world. The West Greenland Shelf (WGS), however, is a region where this process has never been documented. In this study, we use a numerical model with a 1/4° resolution to determine (i) if cascading could happen from the WGS; (ii) where and when it could take place; (iii) the forcings that induce or halt this process; and (iv) the path of the dense plume. Results show cascading happening off the WGS at Davis Strait. Dense waters form there due to brine rejection and slide down the slope during spring. Once the dense plume leaves the shelf, it gradually mixes with waters of similar density and moves northward into Baffin Bay. Our simulation showed events happening between 2003-2006 and during 2014; but no plume was observed in the simulation between 2007 and 2013. We suggest that the reason why cascading was halted in this period is related to: the increased freshwater transport from the Arctic Ocean through Fram Strait; the additional sea ice melting in the region; and the reduced presence of Irminger Water at Davis Strait during fall/early winter. Although observations at Davis Strait show that our simulation usually overestimates the seasonal range of temperature and salinity, they agree with the overall variability captured by the model. This suggests that cascades have the potential to develop on the WGS, albeit less dense than the ones estimated by the simulation.

Programmable Logic Application Notes

NASA Technical Reports Server (NTRS)

Katz, Richard

2000-01-01

This column will be provided each quarter as a source for reliability, radiation results, NASA capabilities, and other information on programmable logic devices and related applications. This quarter will continue a series of notes concentrating on analysis techniques with this issue's section discussing: Digital Timing Analysis Tools and Techniques. Articles in this issue include: SX and SX-A Series Devices Power Sequencing; JTAG and SXISX-AISX-S Series Devices; Analysis Techniques (i.e., notes on digital timing analysis tools and techniques); Status of the Radiation Hard reconfigurable Field Programmable Gate Array Program, Input Transition Times; Apollo Guidance Computer Logic Study; RT54SX32S Prototype Data Sets; A54SX32A - 0.22 micron/UMC Test Results; Ramtron FM1608 FRAM; and Analysis of VHDL Code and Synthesizer Output.

Evolution of microwave sea ice signatures during early summer and midsummer in the marginal ice zone

NASA Technical Reports Server (NTRS)

Onstott, R. G.; Grenfell, T. C.; Matzler, C.; Luther, C. A.; Svendsen, E. A.

1987-01-01

Emissivities at frequencies from 5 to 94 GHz and backscatter at frequencies from 1 to 17 GHz were measured from sea ice in Fram Strait during the marginal Ice Zone Experiment in June and July of 1983 and 1984. The ice observed was primarily multiyear; the remainder, first-year ice, was often deformed. Results from this active and passive microwave study include the description of the evolution of the sea ice during early summer and midsummer; the absorption properties of summer snow; the interrelationship between ice thickness and the state and thickness of snow; and the modulation of the microwave signature, especially at the highest frequencies, by the freezing of the upper few centimeters of the ice.

Cold-seep ostracods from the western Svalbard margin: direct palaeo-indicator for methane seepage?

NASA Astrophysics Data System (ADS)

Yasuhara, Moriaki; Sztybor, Kamila; Rasmussen, Tine L.; Okahashi, Hisayo; Sato, Runa; Tanaka, Hayato

2018-01-01

Despite their high abundance and diversity, microfossil taxa adapted to a particular chemosynthetic environment have rarely been studied and are therefore poorly known. Here we report on an ostracod species, Rosaliella svalbardensis gen. et sp. nov., from a cold methane seep site at the western Svalbard margin, Fram Strait. The new species shows a distinct morphology, different from other eucytherurine ostracod genera. It has a marked similarity to Xylocythere, an ostracod genus known from chemosynthetic environments of wood falls and hydrothermal vents. Rosaliella svalbardensis is probably an endemic species or genus linked to methane seeps. We speculate that the surface ornamentation of pore clusters, secondary reticulation, and pit clusters may be related to ectosymbiosis with chemoautotrophic bacteria. This new discovery of specialized microfossil taxa is important because they can be used as an indicator species for past and present seep environments (http://zoobank.org/urn:lsid:zoobank.org:pub:6075FF30-29D5-4DAB-9141-AE722CD3A69B).

VizieR Online Data Catalog: New minima timings and RVs for 3 eclipsing binaries (Zasche+, 2017)

NASA Astrophysics Data System (ADS)

Zasche, P.; Jurysek, J.; Nemravova, J.; Uhlar, R.; Svoboda, P.; Wolf, M.; Honkova, K.; Masek, M.; Prouza, M.; Cechura, J.; Korcakova, D.; Slechta, M.

2018-04-01

Spectroscopy was obtained in two observatories. Most of the data points for these systems came from the Ondrejov observatory and its 2 m telescope (resolution R~12500). Additionally, data on BR Ind and some data on QS Aql were obtained with the FEROS instrument mounted on the 2.2 m MPG telescope located in La Silla Observatory in Chile (R~48000). Photometry for these three systems was collected over the time span of 2008 to 2016. Owing to the relatively high brightness of the targets, only rather small telescopes were used for these photometric observations. The system V773 Cas was observed (by one of the authors, PS) with a 34 mm refractor at a private observatory in Brno, Czech Republic, using an SBIG ST-7XME CCD camera. The star QS Aql was monitored (by one of the authors, RU) with a similar instrument at a private observatory in Jilove u Prahy, Czech Republic, using a G2-0402 CCD camera. The only southern star, BR Ind, was observed with the FRAM telescope (Prouza et al. 2010AdAst2010E..31P), installed and operated at the Pierre Auger Observatory at Malargue, Argentina. (2 data files).

A propagating freshwater mode in the Arctic Ocean with multidecadal time scale

NASA Astrophysics Data System (ADS)

Schmith, Torben; Malskær Olsen, Steffen; Margrethe Ringgaard, Ida

2017-04-01

We apply Principal Oscillatory Pattern analysis to the Arctic Ocean fresh water content as simulated in a 500 year long control run with constant preindustrial forcing with the EC-Earth global climate model. Two modes emerge from this analysis. One mode is a standing mode with decadal time scale describing accumulation and release of fresh water in the Beaufort Gyre, known in the literature as the Beaufort Gyre flywheel. In addition, we identify a propagating mode with a time scale around 80 years, propagating along the rim of the Canadian Basin. This mode has maximum variability of the fresh water content in the Transpolar Drift and represents the bulk of the total variability of the fresh water content in the Arctic Ocean and also projects on the fresh water through the Fram Strait. Therefore, potentially, it can introduce a multidecadal variability to the Atlantic meridional overturning circulation. We will discuss the physical origin of this propagating mode. This include planetary-scale internal Rossby waves with multidecadal time scale, due to the slow variation of the Coriolis parameter at these high latitudes, as well as topographic steering of these Rossby waves.

AUV based study on physical and ecological processes at fronts

NASA Astrophysics Data System (ADS)

Tippenhauer, Sandra; Wulff, Thorben; Von Appen, Wilken-Jon

2017-04-01

Small-scale processes and their effects get more and more attention when it comes to understanding processes and changes in the (Arctic) ocean. Here we present a study on physical processes and ecological responses at submesoscale frontal systems in the Fram Strait investigated using an autonomous underwater vehicle (AUV). The AUV is equipped with physical and biogeochemical sensors such as an acoustic Doppler current profiler, a turbulence probe, a conductivity-temperature-depth probe, and sensors for Oxygen, Nitrate, Chlorophyll a, and photosynthetically active radiation (PAR). The study is designed such that the AUV covers tracks of several kilometers length in cross-frontal direction with the front roughly located in the middle of the track. On its way, the AUV records high-resolution vertical or zigzag profiles of the physical and biogeochemical properties in the upper 50 m which includes the euphotic zone. In both, physical and biogeochemical terms, the measurements revealed a complex structure of the water column. At the fronts the distribution of phytoplankton and nutrients was highly inhomogeneous, possibly due to wind-driven frontogenesis or the growth of mixed layer eddies. To set the observations into a larger context we also examine ship-based and satellite data. We investigate how the observed patterns of the potential vorticity and the biogeochemical properties may be formed and which processes could lead to a smoothing of the observed gradients.

Collection of LAI and FPAR Data Over The Terra Core Sites

NASA Technical Reports Server (NTRS)

Myneni, Ranga B.; Knjazihhin, J.; Tian, Y.; Wang, Y.

2001-01-01

The objective of our effort was to collect and archive data on LAI (leaf area index) and FPAR (Fraction of Photosynthetically active Radiation absorbed by vegetation) at the EOS Core validation sites as well as to validate and evaluate global fields of LAI and FPAR derived from atmospherically corrected MODIS (Moderate Resolution Imaging Spectrometer) surface reflectance data by comparing these fields with the EOS Core validation data set. The above has been accomplished by: (a) the participation in selected field campaigns within the EOS Validation Program; (b) the processing of the collected data so that suitable comparison between field measurements and the MODIS LAI/FPAR fields can be made; (c) the comparison of the MODAS LAI/FRAM fields with the EOS Terra Core validation data set.

Active/passive microwave sensor comparison of MIZ-ice concentration estimates. [Marginal Ice Zone (MIZ)

NASA Technical Reports Server (NTRS)

Burns, B. A.; Cavalieri, D. J.; Keller, M. R.

1986-01-01

Active and passive microwave data collected during the 1984 summer Marginal Ice Zone Experiment in the Fram Strait (MIZEX 84) are used to compare ice concentration estimates derived from synthetic aperture radar (SAR) data to those obtained from passive microwave imagery at several frequencies. The comparison is carried out to evaluate SAR performance against the more established passive microwave technique, and to investigate discrepancies in terms of how ice surface conditions, imaging geometry, and choice of algorithm parameters affect each sensor. Active and passive estimates of ice concentration agree on average to within 12%. Estimates from the multichannel passive microwave data show best agreement with the SAR estimates because the multichannel algorithm effectively accounts for the range in ice floe brightness temperatures observed in the MIZ.

Observation of variations in the composition of sea ice in the Greenland MIZ during early summer 1983 with the Nimbus-7 SMMR. [Marginal Ice Zone (MIZ); Scanning Multichannel Microwave radiometer (SMMR)

NASA Technical Reports Server (NTRS)

Gloersen, P.; Campbell, W. J.

1984-01-01

Data acquired with the Scanning Multichannel Microwave Radiometer (SMMR) on board the Nimbus-7 Satellite for a six-week period in Fram Strait were analyzed with a procedure for calculating sea ice concentration, multiyear fraction, and ice temperature. Calculations were compared with independent observations made on the surface and from aircraft to check the validity of the calculations based on SMMR data. The calculation of multiyear fraction, which was known to be invalid near the melting point of sea ice, is discussed. The indication of multiyear ice is found to disappear a number of times, presumably corresponding to freeze/thaw cycles which occurred in this time period.

Nonlinear dead water resistance at subcritical speed

NASA Astrophysics Data System (ADS)

Grue, John

2015-08-01

The dead water resistance F 1 = /1 2 C d w ρ S U 2 (ρ fluid density, U ship speed, S wetted body surface, Cdw resistance coefficient) on a ship moving at subcritical speed along the upper layer of a two-layer fluid is calculated by a strongly nonlinear method assuming potential flow in each layer. The ship dimensions correspond to those of the Polar ship Fram. The ship draught, b0, is varied in the range 0.25h0-0.9h0 (h0 the upper layer depth). The calculations show that Cdw/(b0/h0)2 depends on the Froude number only, in the range close to critical speed, Fr = U/c0 ˜ 0.875-1.125 (c0 the linear internal long wave speed), irrespective of the ship draught. The function Cdw/(b0/h0)2 attains a maximum at subcritical Froude number depending on the draught. Maximum Cdw/(b0/h0)2 becomes 0.15 for Fr = 0.76, b0/h0 = 0.9, and 0.16 for Fr = 0.74, b0/h0 = 1, where the latter extrapolated value of the dead water resistance coefficient is about 60 times higher than the frictional drag coefficient and relevant for the historical dead water observations. The nonlinear Cdw significantly exceeds linear theory (Fr < 0.85). The ship generated waves have a wave height comparable to the upper layer depth. Calculations of three-dimensional wave patterns at critical speed compare well to available laboratory experiments. Upstream solitary waves are generated in a wave tank of finite width, when the layer depths differ, causing an oscillation of the force. In a wide ocean, a very wide wave system develops at critical speed. The force approaches a constant value for increasing time.

Implementation of the high-order schemes QUICK and LECUSSO in the COMMIX-1C Program

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sakai, K.; Sun, J.G.; Sha, W.T.

Multidimensional analysis computer programs based on the finite volume method, such as COMMIX-1C, have been commonly used to simulate thermal-hydraulic phenomena in engineering systems such as nuclear reactors. In COMMIX-1C, the first-order schemes with respect to both space and time are used. In many situations such as flow recirculations and stratifications with steep gradient of velocity and temperature fields, however, high-order difference schemes are necessary for an accurate prediction of the fields. For these reasons, two second-order finite difference numerical schemes, QUICK (Quadratic Upstream Interpolation for Convective Kinematics) and LECUSSO (Local Exact Consistent Upwind Scheme of Second Order), have beenmore » implemented in the COMMIX-1C computer code. The formulations were derived for general three-dimensional flows with nonuniform grid sizes. Numerical oscillation analyses for QUICK and LECUSSO were performed. To damp the unphysical oscillations which occur in calculations with high-order schemes at high mesh Reynolds numbers, a new FRAM (Filtering Remedy and Methodology) scheme was developed and implemented. To be consistent with the high-order schemes, the pressure equation and the boundary conditions for all the conservation equations were also modified to be of second order. The new capabilities in the code are listed. Test calculations were performed to validate the implementation of the high-order schemes. They include the test of the one-dimensional nonlinear Burgers equation, two-dimensional scalar transport in two impinging streams, von Karmann vortex shedding, shear driven cavity flow, Couette flow, and circular pipe flow. The calculated results were compared with available data; the agreement is good.« less

Exploring Arctic history through scientific drilling

NASA Astrophysics Data System (ADS)

ODP Leg 151 Shipboard Scientific Party

During the brief Arctic summer of 1993, the Ocean Drilling Program's research vessel JOIDES Resolution recovered the first scientific drill cores from the eastern Arctic Ocean. Dodging rafts of pack ice shed from the Arctic ice cap, the science party sampled sediments north of 80°N latitude from the Yermak Plateau, as well as from sites in Fram Strait, the northeastern Greenland margin, and the Iceland Plateau (Figure 1).The sediments collected reveal the earliest history of the connection between the North Atlantic and Arctic Oceans through the Nordic Seas. The region between Greenland and Norway first formed a series of isolated basins, sometimes with restricted deep circulation, that eventually joined and allowed deep and surface Arctic Ocean water to invade the region. A record was also retrieved that shows major glaciation in the region began about 2.5 m.y.a.

Late summer sea ice segmentation with multi-polarisation SAR features in C- and X-band

NASA Astrophysics Data System (ADS)

Fors, A. S.; Brekke, C.; Doulgeris, A. P.; Eltoft, T.; Renner, A. H. H.; Gerland, S.

2015-09-01

In this study we investigate the potential of sea ice segmentation by C- and X-band multi-polarisation synthetic aperture radar (SAR) features during late summer. Five high-resolution satellite SAR scenes were recorded in the Fram Strait covering iceberg-fast first-year and old sea ice during a week with air temperatures varying around zero degrees Celsius. In situ data consisting of sea ice thickness, surface roughness and aerial photographs were collected during a helicopter flight at the site. Six polarimetric SAR features were extracted for each of the scenes. The ability of the individual SAR features to discriminate between sea ice types and their temporally consistency were examined. All SAR features were found to add value to sea ice type discrimination. Relative kurtosis, geometric brightness, cross-polarisation ratio and co-polarisation correlation angle were found to be temporally consistent in the investigated period, while co-polarisation ratio and co-polarisation correlation magnitude were found to be temporally inconsistent. An automatic feature-based segmentation algorithm was tested both for a full SAR feature set, and for a reduced SAR feature set limited to temporally consistent features. In general, the algorithm produces a good late summer sea ice segmentation. Excluding temporally inconsistent SAR features improved the segmentation at air temperatures above zero degrees Celcius.

APPROACHING CRYOGENIC GE PERFORMANCE WITH PELTIER COOLED CDTE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khusainov, A. K.; Iwanczyk, J. S.; Patt, B. E.

A new class of hand-held, portable spectrometers based on large area (lcm2) CdTe detectors of thickness up to 3mm has been demonstrated to produce energy resolution of between 0.3 and 0.5% FWHM at 662 keV. The system uses a charge loss correction circuit for improved efficiency, and detector temperature stabilization to ensure consistent operation of the detector during field measurements over a wide range of ambient temperature. The system can operate continuously for up to 8hrs on rechargeable batteries. The signal output from the charge loss corrector is compatible with most analog and digital spectroscopy amplifiers and multi channel analyzers.more » Using a detector measuring 11.2 by 9.1 by 2.13 mm3, we have recently been able to obtain the first wide-range plutonium gamma-ray isotopic analysis with other than a cryogenically cooled germanium spectrometer. The CdTe spectrometer is capable of measuring small plutonium reference samples in about one hour, covering the range from low to high burnup. The isotopic analysis software used to obtain these results was FRAM, Version 4 from LANL. The new spectrometer is expected to be useful for low-grade assay, as well as for some in-situ plutonium gamma-ray isotopics in lieu of cryogenically cooled Ge.« less

Ice Fog and Light Snow Measurements Using a High-Resolution Camera System

NASA Astrophysics Data System (ADS)

Kuhn, Thomas; Gultepe, Ismail

2016-09-01

Ice fog, diamond dust, and light snow usually form over extremely cold weather conditions, and they affect both visibility and Earth's radiative energy budget. Prediction of these hydrometeors using models is difficult because of limited knowledge of the microphysical properties at the small size ranges due to measurement issues. These phenomena need to be better represented in forecast and climate models; therefore, in addition to remote sensing accurate measurements using ground-based instrumentation are required. An imaging instrument, aimed at measuring ice fog and light snow particles, has been built and is presented here. The ice crystal imaging (ICI) probe samples ice particles into a vertical, tapered inlet with an inlet flow rate of 11 L min-1. A laser beam across the vertical air flow containing the ice crystals allows for their detection by a photodetector collecting the scattered light. Detected particles are then imaged with high optical resolution. An illuminating LED flash and image capturing are triggered by the photodetector. In this work, ICI measurements collected during the fog remote sensing and modeling (FRAM) project, which took place during Winter of 2010-2011 in Yellowknife, NWT, Canada, are summarized and challenges related to measuring small ice particles are described. The majority of ice particles during the 2-month-long campaign had sizes between 300 and 800 μm. During ice fog events the size distribution measured had a lower mode diameter of 300 μm compared to the overall campaign average with mode at 500 μm.

Atlantic Water Advection and Ice Sheet-Ocean Feedbacks in the Arctic Ocean During the Last 200 ky

NASA Astrophysics Data System (ADS)

Spielhagen, R. F.; Mackensen, A.; Stein, R. H.

2016-12-01

Earlier work on Arctic deep-sea cores from the eastern Lomonosov Ridge and the Morris Jesup Rise had revealed that large-scale Eurasian ice sheet growth was initiated at times with seasonally open waters in the Arctic Ocean, indicating a role for the ocean in nearby ice sheet development in the last 200 ky. Here we present microfossil and geochemical data from new sediment cores obtained from the western and easternmost Lomonosov Ridge during the PS87 expedition (2014) of RV Polarstern, amended by data from refined analyses of the older cores. They allow to investigate in more detail the feedbacks between Atlantic Water (AW) advection, sea ice, and ice sheets. In all cores, high microfossil abundances are found just below layers rich in iceberg-rafted detritus, supporting the hypothesis of Arctic Ocean moisture supply for the growth of Eurasian ice sheets. On the other hand, the new microfaunal results suggest that the decay of the ice sheets and the enhanced freshwater discharge to the Arctic may have influenced the routing of subsurface AW in the Arctic Ocean, at least during marine isotope (sub)stages (MIS) 5a and 5e. In the early part of these relatively mild climatic intervals, faunal and isotopic data suggest a noticable advection of Atlantic Water, yet of rather low temperature and likely at depths comparable to the modern distribution (i.e., below 150 m) or even deeper. This may be explained by a more southerly position of AW cooling and submergence than today, caused by a thick layer of low saline waters near the surface which stemmed from the slow melting of ice sheet remnants on the Eurasian continent and shelves. In the second half of both MIS 5a and 5e, AW advection was significantly stronger and may have occurred at shallower depths, as indicated by unusually large amounts of small subpolar planktic foraminifers in central Arctic sediments. AW was apparently diverted northward from the Fram Strait and spread eastward along the Lomonosov Ridge. A possible explanation is the persistence of a water mass of similarly high density in the upper Eurasian Basin, possibly replenished by intensive sea ice formation and brine rejection. The results suggest a rather long-lasting influence of continental ice on the Arctic Ocean which led to a current pattern in MIS 5a and 5e significantly different from the Holocene style.

Sea ice studies in the Spitsbergen-Greenland area

NASA Technical Reports Server (NTRS)

Vinje, T. E. (Principal Investigator)

1976-01-01

The author has identified the following significant results. Detailed information on the outflow through the Fram Strait of ice from the Polar Ocean over shorter periods was obtained. It is found that the speed of the outflow may vary about 100% over periods of a few days. The core of the East Greenland Current is found between 2 deg E and 4 deg W. The speed of the surface water at 81 deg N is for a calm period estimated to be about 10 cm/s. A new surging glacier was discovered and new fronts of several glaciers were determined. The variation of the snow line with respect to distance from the coast was for the first time determined for the southern part of Spitsbergen. Great variations were observed, from 200 m in east to 550 m in the central area of the island.

Pteropods counter mechanical damage and dissolution through extensive shell repair.

PubMed

Peck, Victoria L; Oakes, Rosie L; Harper, Elizabeth M; Manno, Clara; Tarling, Geraint A

2018-01-17

The dissolution of the delicate shells of sea butterflies, or pteropods, has epitomised discussions regarding ecosystem vulnerability to ocean acidification over the last decade. However, a recent demonstration that the organic coating of the shell, the periostracum, is effective in inhibiting dissolution suggests that pteropod shells may not be as susceptible to ocean acidification as previously thought. Here we use micro-CT technology to show how, despite losing the entire thickness of the original shell in localised areas, specimens of polar species Limacina helicina maintain shell integrity by thickening the inner shell wall. One specimen collected within Fram Strait with a history of mechanical and dissolution damage generated four times the thickness of the original shell in repair material. The ability of pteropods to repair and maintain their shells, despite progressive loss, demonstrates a further resilience of these organisms to ocean acidification but at a likely metabolic cost.

An FPGA-Based Test-Bed for Reliability and Endurance Characterization of Non-Volatile Memory

NASA Technical Reports Server (NTRS)

Rao, Vikram; Patel, Jagdish; Patel, Janak; Namkung, Jeffrey

2001-01-01

Memory technologies are divided into two categories. The first category, nonvolatile memories, are traditionally used in read-only or read-mostly applications because of limited write endurance and slow write speed. These memories are derivatives of read only memory (ROM) technology, which includes erasable programmable ROM (EPROM), electrically-erasable programmable ROM (EEPROM), Flash, and more recent ferroelectric non-volatile memory technology. Nonvolatile memories are able to retain data in the absence of power. The second category, volatile memories, are random access memory (RAM) devices including SRAM and DRAM. Writing to these memories is fast and write endurance is unlimited, so they are most often used to store data that change frequently, but they cannot store data in the absence of power. Nonvolatile memory technologies with better future potential are FRAM, Chalcogenide, GMRAM, Tunneling MRAM, and Silicon-Oxide-Nitride-Oxide-Silicon (SONOS) EEPROM.

Enhanced sea-ice export from the Arctic during the Younger Dryas.

PubMed

Not, Christelle; Hillaire-Marcel, Claude

2012-01-31

The Younger Dryas cold spell of the last deglaciation and related slowing of the Atlantic meridional overturning circulation have been linked to a large array of processes, notably an influx of fresh water into the North Atlantic related to partial drainage of glacial Lake Agassiz. Here we observe a major drainage event, in marine sediment cores raised from the Lomonosov Ridge, in the central Arctic Ocean marked by a pulse in detrital dolomitic-limestones. This points to an Arctic-Canadian sediment source area with about fivefold higher Younger Dryas ice-rafting deposition rate, in comparison with the Holocene. Our findings thus support the hypothesis of a glacial drainage event in the Canadian Arctic area, at the onset of the Younger Dryas, enhancing sea-ice production and drifting through the Arctic, then export through Fram Strait, towards Atlantic meridional overturning circulation sites of the northern North Atlantic.

Microwave and physical properties of sea ice in the winter marginal ice zone

NASA Technical Reports Server (NTRS)

Tucker, W. B., III; Perovich, D. K.; Gow, A. J.; Grenfell, T. C.; Onstott, R. G.

1991-01-01

Surface-based active and passive microwave measurements were made in conjunction with ice property measurements for several distinct ice types in the Fram Strait during March and April 1987. Synthesis aperture radar imagery downlinked from an aircraft was used to select study sites. The surface-based radar scattering cross section and emissivity spectra generally support previously inferred qualitative relationships between ice types, exhibiting expected separation between young, first-year and multiyear ice. Gradient ratios, calculated for both active and passive data, appear to allow clear separation of ice types when used jointly. Surface flooding of multiyear floes, resulting from excessive loading and perhaps wave action, causes both active and passive signatures to resemble those of first-year ice. This effect could possibly cause estimates of ice type percentages in the marginal ice zone to be in error when derived from aircraft- or satellite-born sensors.

Space/Time Statistics of Polar Ice Motion

NASA Technical Reports Server (NTRS)

Emery, William J.; Fowler, Charles; Maslanik, James A.

2003-01-01

Ice motions have been computed from passive microwave imagery (SMMR and SSM/I) on a daily basis for both Polar Regions. In the Arctic these daily motions have been merged with daily motions from AVHRR imagery and the Arctic buoy program. In the Antarctic motion only from the AVHRR were available for merging with the passive microwave vectors. Long-term means, monthly means and weekly means have all been computed from the resulting 22-year time series of polar ice motion. Papers are in preparation that present the long term (22 year) means, their variability and show animations of the monthly means over this time period for both Polar Regions. These papers will have links to "enhanced objects" that allow the reader to view the animations as part of the paper. The first paper presents the ice motion results from each of the Polar Regions. The second paper looks only at ice motion in the Arctic in order to develop a time series of ice age in the Arctic. Starting with the first full SMMR year in 1979 we keep track of each individual "ice element" (resolution of the sensor) and track it in the subsequent monthly time series. After a year we "age" each "particle" and we thus can keep track of the age of the ice starting in 1979. We keep track of ice age classes between one and five years and thus we can see the evolution of the ice as it ages after the initial 5-year period. This calculation shows how we are losing the older ice through Fram Strait at a rather alarming rate particularly in the past 15 years. This loss of older ice has resulted in an overall decrease in the thickest, oldest ice, which is now limited to a region just north of the Canadian Archipelago with tongues extending out across the pole towards the Siberian Shelf. This loss of old ice is consistent with the effects of global warming which provides the heat needed to melt, move and disperse this oldest ice through Fram Strait. This is the first step in a progression that may eventually open the Arctic ice pack and lead to an ice-free Arctic Ocean.

Late Pliocene/Pleistocene changes in Arctic sea-ice cover: Biomarker and dinoflagellate records from Fram Strait/Yermak Plateau (ODP Sites 911 and 912)

NASA Astrophysics Data System (ADS)

Stein, Ruediger; Fahl, Kirsten; Matthiessen, Jens

2014-05-01

Sea ice is a critical component in the (global) climate system that contributes to changes in the Earth's albedo (heat reduction) and biological processes (primary productivity), as well as deep-water formation, a driving mechanism for global thermohaline circulation. Thus, understanding the processes controlling Arctic sea ice variability is of overall interest and significance. Recently, a novel and promising biomarker proxy for reconstruction of Arctic sea-ice conditions was developed and is based on the determination of a highly-branched isoprenoid with 25 carbons (IP25; Belt et al., 2007; PIP25 when combined with open-water phytoplankton biomarkers; Müller et al., 2011). Here, we present biomarker data from Ocean Drilling Program (ODP) Sites 911 and 912, recovered from the southern Yermak Plateau and representing information of sea-ice variability, changes in primary productivity and terrigenous input during the last about 3.5 Ma. As Sites 911 and 912 are close to the modern sea-ice edge, their sedimentary records seem to be optimal for studying past variability in sea-ice coverage and testing the applicability of IP25 and PIP25 in older sedimentary sequences. In general, our biomarker records correlate quite well with other climate and sea-ice proxies (e.g., dinoflagellates, IRD, etc.). The main results can be summarized as follows: (1) The novel IP25/PIP25 biomarker approach has potential for semi-quantitative paleo-sea ice studies covering at least the last 3.5 Ma, i.e., the time interval including the onset (intensification) of major Northern Hemisphere Glaciation (NHG). (2) These data indicate that sea ice of variable extent was present in the Fram Strait/southern Yermak Plateau area during most of the time period under investigation. (3) Elevated IP25/PIP25 values indicative for an extended spring sea-ice cover, already occurred between 3.6 and 2.9 Ma, i.e., prior to the onset of major NHG. This may suggest that sea-ice and related albedo effects might have been important for general cooling and ice-sheet build-up. (4) Maxima in sea ice occurred near 3.3, 2.7, 2.1, 1.7 and during the last 1.2 Ma whereas between about 2.6 and 2.2 Ma the sea-ice cover was surprisingly reduced. The IP25 maxima are similar to those determined for the late Holocene. (5) Both, dinoflagellate and IP25/PIP25 data indicate that also during the Late Pliocene Warming Event at least occasionally sea ice must have occurred. (6) This low-resolution pilot study motivates to carry out further detailed high-resolution sea-ice biomarker research on ODP/IODP material in order to prove or disprove these preliminary interpretations. References Belt, S.T., Massé, G., Rowland, S.J., Poulin, M., Michel, C., LeBlanc, B., 2007. A novel chemical fossil of palaeo sea ice: IP25. Organic Geochemistry 38, 16-27. Müller, J., Wagner, A., Fahl, K., Stein, R., Prange, M., Lohmann, G., 2011. Towards quantitative sea ice reconstructions in the northern North Atlantic: A combined biomarker and numerical modelling approach. Earth Planetary Science Letters 306, 137-148.

Data report on variations in the composition of sea ice during MIZEX/East'83 with the Nimbus-7 SMMR

NASA Technical Reports Server (NTRS)

Gloersen, P.

1984-01-01

Data acquired with the scanning multichannel microwave radiometer (SMMR) on board the Nimbus-7 satellite for a six-week period including the 1983 MIZEX in Fram Strait were analyzed with the use of a previously developed procedure for calculating sea ice concentration, multiyear fraction, and ice temperature. These calculations can compared with independent observations made on the surface and from aircraft in order to check the validity of the calculations based on SMMR data. The calculation of multiyear fraction, which was known earlier to be invalid near the melting point of sea ice, was of particular interest during this period. The indication of multiyear ice was found to disappear a number of times, presumably corresponding to freeze/thaw cycles which occurred in this time period. Both grid-print maps and grey-scale images of total sea ice concentration and multiyear sea ice fraction for the entire period are included.

MIZEX, 1984, NASA CV-990 flight report

NASA Technical Reports Server (NTRS)

1985-01-01

During June/July 1984, the NASA CV-990 Airborne Laboratory was utilized in a mission to overly the Fram Strait/East Greenland Sea marginal ice zone (MIZ) during the main summer marginal ice zone experiment (MIZEX '84). The eight data flights were coordinated where possible with overpasses of the Nimbus-7 satellite, and with measurement of sea ice, open ocean, and atmospheric properties at the surface. The surface research teams were based on seven research vessels, some with helicopters: (1) M/V Kvitbjorn, (2) M/V Polarqueen; (3) M/S Haakon Mosby; (4) a M/S H.U. Sverdrup, all from Norway; (5) F/S Polarstern from the Federal Republic of Germany; and (6) the USNS Lynch from the USA. There were also coordinated flights with the NRL P3, NOAA P3, Canadian CV580, and the French B-17 during the overlap portions of their respective missions. Analysis of the real-time data acquired during the mission and uncalibrated data stored on tape has served to indicate the mission was over 90% successful.

Satellite Test of Radiation Impact on Ramtron 512K FRAM

NASA Technical Reports Server (NTRS)

MacLeod, Todd C.; Sayyah, Rana; Sims, W. Herb; Varnavas, Kosta A.; Ho, Fat D.

2009-01-01

The Memory Test Experiment is a space test of a ferroelectric memory device on a low Earth orbit satellite. The test consists of writing and reading data with a ferroelectric based memory device. Any errors are detected and are stored on board the satellite. The data is send to the ground through telemetry once a day. Analysis of the data can determine the kind of error that was found and will lead to a better understanding of the effects of space radiation on memory systems. The test will be one of the first flight demonstrations of ferroelectric memory in a near polar orbit which allows testing in a varied radiation environment. The memory devices being tested is a Ramtron Inc. 512K memory device. This paper details the goals and purpose of this experiment as well as the development process. The process for analyzing the data to gain the maximum understanding of the performance of the ferroelectric memory device is detailed.

Ice fog and light snow measurements using a high resolution camera system

NASA Astrophysics Data System (ADS)

Kuhn, Thomas; Gultepe, Ismail

2016-04-01

In this presentation, measurements collected by the ice crystal imaging (ICI) probe employed during FRAM (Fog Remote Sensing and Modeling) project for the Winter of 2010-2011 in Yellowknife, NWT, Canada are analysed to study small ice crystal impact on aviation operations. Ice fog, diamond dust, and light snow form during cold weather conditions and they affect aviation operations through visibility and deposition over the surfaces. In addition, these events influence the local heat budget through radiative cooling. Prediction of these hydrometeors using models is difficult because of limited knowledge of the microphysical properties at the small size ranges. These phenomena need to be better represented in forecast and climate models and this can only be done using accurate measurements from ground-based instrumentation. Imaging of ice particles' properties can complement other in-situ measurements being collected routinely. The newly developed ICI probe, aimed at measuring ice fog and light snow particles, is presented here. The ICI probe samples ice particles through a vertical inlet, where a laser beam and photodetector detect ice crystals contained in the flow. The detected particles are then imaged with high optical resolution between 10 to 1000 micron size range. An illuminating LED flash and image capturing for measurements are triggered by the photodetector. The results suggested that the majority of ice particles during the two-month long campaign were small with sizes between 300 μm and 800 μm. During ice fog events, the size distribution measured had a lower mode diameter of 300 μm compared to the overall campaign average with mode at 500 μm. In this presentation, challenges and issues related to small ice crystals are described and their importance for aviation operations and climate change are discussed.

Arctic lead detection using a waveform unmixing algorithm from CryoSat-2 data

NASA Astrophysics Data System (ADS)

Lee, S.; Im, J.

2016-12-01

Arctic areas consist of ice floes, leads, and polynyas. While leads and polynyas account for small parts in the Arctic Ocean, they play a key role in exchanging heat flux, moisture, and momentum between the atmosphere and ocean in wintertime because of their huge temperature difference In this study, a linear waveform unmixing approach was proposed to detect lead fraction. CryoSat-2 waveforms for pure leads, sea ice, and ocean were used as end-members based on visual interpretation of MODIS images coincident with CryoSat-2 data. The unmixing model produced lead, sea ice, and ocean abundances and a threshold (> 0.7) was applied to make a binary classification between lead and sea ice. The unmixing model produced better results than the existing models in the literature, which are based on simple thresholding approaches. The results were also comparable with our previous research using machine learning based models (i.e., decision trees and random forest). A monthly lead fraction was calculated, dividing the number of detected leads by the total number of measurements. The lead fraction around Beaufort Sea and Fram strait was high due to the anti-cyclonic rotation of Beaufort Gyre and the outflows of sea ice to the Atlantic. The lead fraction maps produced in this study were matched well with monthly lead fraction maps in the literature. The areas with thin sea ice identified from our previous research correspond to the high lead fraction areas in the present study. Furthermore, sea ice roughness from ASCAT scatterometer was compared to a lead fraction map to see the relationship between surface roughness and lead distribution.

An Arctic Ocean freshwater event as the trigger of the Younger Dryas stadial? Answers from Arctic deep-sea sediment cores

NASA Astrophysics Data System (ADS)

Spielhagen, Robert F.

2017-04-01

At ca. 12.8-11.5 ka the northern hemisphere climate experienced a dramatic fall-back to quasi-glacial conditions. Since the late 1980s, a major meltwater ejection to the North Atlantic through the Gulf of St.Lawrence was considered the most likely trigger for this "Younger Dryas event". It may have caused a slowdown of the Atlantic meridional overturning circulation (AMOC) and a diminished heat transport to the northern latitudes. However, field evidence from the potential meltwater route in North America has been discussed controversially in the last years, and the detection of a freshwater signal in marine sediments off the St.Lawrence river rendered difficult. More recently, the idea of an "Arctic route" of meltwater originating from proglacial lake Agassiz was put forward (Tarasov & Peltier, Nature 2005) and has gained further attraction through evidence from radiogenic isotopes (Not and Hillaire-Marcel; Nature Comm., 2012) and through modelling results of Condron and Winsor (PNAS, 2012) which showed that only a freshwater outflow through Fram Strait was capable of triggering a climate perturbation like the Younger Dryas. Here I present a review of isotopic records from the Arctic Ocean, the Fram Strait, and the Greenland Sea in search of evidence for a strong freshwater event in the Arctic Ocean at the onset of the Younger Dryas, supporting an Arctic origin of the trigger. A number of Arctic cores show a light planktic oxygen isotope spike at 13 ka. For several of them the age model is detailed enough to exclude a confusion with other deglacial spikes. On the central Arctic Lomonosov Ridge there is even evidence for a diminshed intermediate/bottom water circulation immediately following the freshwater event. On the other hand, there are many records which do not show a meltwater spike in the critical time interval, most likely because of low temporal resolution, a thick ice cover and/or a habitat change of the planktic foraminifers. The largest uncertainty is introduced by arguable reservoir corrections which may need to be applied to radiocarbon datings from the last glacial termination. Nevertheless, since isotopic evidence for a freshwater event at ca. 13 ka is found also in the Greenland Sea, support for an "Arctic trigger" weakening the AMOC is accumulating and may add to the establishment of a new paradigm for the origin of the Younger Dryas cold event.

Late-summer sea ice segmentation with multi-polarisation SAR features in C and X band

NASA Astrophysics Data System (ADS)

Fors, Ane S.; Brekke, Camilla; Doulgeris, Anthony P.; Eltoft, Torbjørn; Renner, Angelika H. H.; Gerland, Sebastian

2016-02-01

In this study, we investigate the potential of sea ice segmentation by C- and X-band multi-polarisation synthetic aperture radar (SAR) features during late summer. Five high-resolution satellite SAR scenes were recorded in the Fram Strait covering iceberg-fast first-year and old sea ice during a week with air temperatures varying around 0 °C. Sea ice thickness, surface roughness and aerial photographs were collected during a helicopter flight at the site. Six polarimetric SAR features were extracted for each of the scenes. The ability of the individual SAR features to discriminate between sea ice types and their temporal consistency were examined. All SAR features were found to add value to sea ice type discrimination. Relative kurtosis, geometric brightness, cross-polarisation ratio and co-polarisation correlation angle were found to be temporally consistent in the investigated period, while co-polarisation ratio and co-polarisation correlation magnitude were found to be temporally inconsistent. An automatic feature-based segmentation algorithm was tested both for a full SAR feature set and for a reduced SAR feature set limited to temporally consistent features. In C band, the algorithm produced a good late-summer sea ice segmentation, separating the scenes into segments that could be associated with different sea ice types in the next step. The X-band performance was slightly poorer. Excluding temporally inconsistent SAR features improved the segmentation in one of the X-band scenes.

Measurement of Arctic sea-ice thickness by submarine 5 years after SCICEX

NASA Astrophysics Data System (ADS)

Hughes, Nicholas E.; Wadhams, Peter

In April 2004 the Royal Navy submarine HMS Tireless became the first UK submarine to conduct environmental monitoring in the Arctic Ocean since 1996. As the last US SCICEX (Scientific Ice Expeditions) cruise was in 2000, this has been the only opportunity for a civilian scientist to carry out measurement of ice draft and oceanography over a wide area of the Arctic. This paper presents preliminary results and compares them with similar investigations in the 1970s-90s. The route of Tireless covered a large area of the European sector of the Arctic from 5° E to 62° W. Transects were carried out from the marginal ice zone in Fram Strait up to the North Pole and along the 85° N parallel north of Greenland. As part of work for the European Commission IRIS project, image intensity from the advanced synthetic aperture radar instrument on the European Space Agency's Envisat satellite has been compared with ice draft from the submarine. The raw data were found to be highly variable, so a moving average was applied, producing a correlation of 0.79. Tireless carried a full oceanographic sensor suite and expendable probes for investigation into changes in the Arctic Ocean. The results from these show further erosion of the Arctic cold halocline layer by advancing Atlantic Water compared to previous climatologies and fieldwork expeditions. Preliminary ice-draft data from 85° N show deeper ice keels than those encountered by a submarine on the same route in 1987.

Evaluation of double-layer density modulated Si thin films as Li-ion battery anodes

NASA Astrophysics Data System (ADS)

Taha Demirkan, Muhammed; Yurukcu, Mesut; Dursun, Burcu; Demir-Cakan, Rezan; Karabacak, Tansel

2017-10-01

Double-layer density modulated silicon thin films which contain alternating low and high density Si film layers were fabricated by magnetron sputtering. Two different samples consisting of alternating layers of high-density/low-density and low-density/high-density Si thin film layers were investigated as anode electrodes in Li-ion batteries. Si thin film in which the terminating layer at the top is low density Si layer-quoted as low-density/high-density film (LD/HD)- exhibits better performance than Si thin film that has high density layer at the top, -quoted as high-density/low-density (HD/LD). A highly stabilized cycling performance with the specific charge capacities of 2000 mAh g-1 at the 150th cycle at C/2 current density, and 1200 mAh g-1 at the 240th cycle at 10 C current density were observed for the LD/HD Si anode in the presence of fluoroethylene carbonate (FEC) electrolyte additive.

High-resolution Ceres LAMO atlas derived from Dawn FC images

NASA Astrophysics Data System (ADS)

Roatsch, T.; Kersten, E.; Matz, K. D.; Preusker, F.; Scholten, F.; Jaumann, R.; Raymond, C. A.; Russell, C.

2016-12-01

Introduction: NASA's Dawn spacecraft has been orbiting the dwarf planet Ceres since December 2015 in LAMO (High Altitude Mapping Orbit) with an altitude of about 400 km to characterize for instance the geology, topography, and shape of Ceres. One of the major goals of this mission phase is the global high-resolution mapping of Ceres. Data: The Dawn mission is equipped with a fram-ing camera (FC). The framing camera took until the time of writing about 27,500 clear filter images in LAMO with a resolution of about 30 m/pixel and dif-ferent viewing angles and different illumination condi-tions. Data Processing: The first step of the processing chain towards the cartographic products is to ortho-rectify the images to the proper scale and map projec-tion type. This process requires detailed information of the Dawn orbit and attitude data and of the topography of the target. A high-resolution shape model was provided by stereo processing of the HAMO dataset, orbit and attitude data are available as reconstructed SPICE data. Ceres' HAMO shape model is used for the calculation of the ray intersection points while the map projection itself was done onto a reference sphere of Ceres. The final step is the controlled mosaicking of all nadir images to a global mosaic of Ceres, the so called basemap. Ceres map tiles: The Ceres atlas will be produced in a scale of 1:250,000 and will consist of 62 tiles that conforms to the quadrangle schema for Venus at 1:5,000,000. A map scale of 1:250,000 is a compro-mise between the very high resolution in LAMO and a proper map sheet size of the single tiles. Nomenclature: The Dawn team proposed to the International Astronomical Union (IAU) to use the names of gods and goddesses of agriculture and vege-tation from world mythology as names for the craters and to use names of agricultural festivals of the world for other geological features. This proposal was ac-cepted by the IAU and the team proposed 92 names for geological features to the IAU based on the LAMO mosaic. These feature names will be applied to the map tiles.

Extreme diversity in the songs of Spitsbergen's bowhead whales.

PubMed

Stafford, K M; Lydersen, C; Wiig, Ø; Kovacs, K M

2018-04-01

Almost all mammals communicate using sound, but few species produce complex songs. Two baleen whales sing complex songs that change annually, though only the humpback whale ( Megaptera novaeangliae ) has received much research attention. This study focuses on the other baleen whale singer, the bowhead whale ( Balaena mysticetus ). Members of the Spitsbergen bowhead whale population produced 184 different song types over a 3-year period, based on duty-cycled recordings from a site in Fram Strait in the northeast Atlantic. Distinct song types were recorded over short periods, lasting at most some months. This song diversity could be the result of population expansion, or immigration of animals from other populations that are no longer isolated from each other by heavy sea ice. However, this explanation does not account for the within season and annual shifting of song types. Other possible explanations for the extraordinary diversity in songs could be that it results either from weak selection pressure for interspecific identification or for maintenance of song characteristics or, alternatively, from strong pressure for novelty in a small population. © 2018 The Authors.

CoNNeCT Antenna Positioning System Dynamic Simulator Modal Model Correlation

NASA Technical Reports Server (NTRS)

Jones, Tevor M.; McNelis, Mark E.; Staab, Lucas D.; Akers, James C.; Suarez, Vicente

2012-01-01

The National Aeronautics and Space Administration (NASA) developed an on-orbit, adaptable, Software Defined Radios (SDR)/Space Telecommunications Radio System (STRS)-based testbed facility to conduct a suite of experiments to advance technologies, reduce risk, and enable future mission capabilities on the International Space Station (ISS). The Communications, Navigation, and Networking reConfigurable Testbed (CoNNeCT) Project will provide NASA, industry, other Government agencies, and academic partners the opportunity to develop and field communications, navigation, and networking technologies in both the laboratory and space environment based on reconfigurable, software-defined radio platforms and the STRS Architecture. The CoNNeCT Payload Operations Nomenclature is "SCAN Testbed," and this nomenclature will be used in all ISS integration, safety, verification, and operations documentation. The SCAN Testbed (payload) is a Flight Releasable Attachment Mechanism (FRAM) based payload that will launch aboard the Japanese H-II Transfer Vehicle (HTV) Multipurpose Exposed Pallet (EP-MP) to the International Space Station (ISS), and will be transferred to the Express Logistics Carrier 3 (ELC3) via Extravehicular Robotics (EVR). The SCAN Testbed will operate on-orbit for a minimum of two years.

Changes in compensatory eye movements associated with simulated stimulus conditions of spaceflight

NASA Technical Reports Server (NTRS)

Harm, Deborah L.; Zografos, Linda M.; Skinner, Noel C.; Parker, Donald E.

1993-01-01

Compensatory vertical eye movement gain (CVEMG) was recorded during pitch oscillation in darkness before, during, and immediately after exposures to the stimulus rearrangement produced by the Preflight Adaptation Trainer (PAT) Tilt-Translation Device (TTD). The TTD is designed to elicit adaptive responses that are similar to those observed in microgravity-adapted astronauts. The data from Experiment 1 yielded a statistically significant CVEMG decrease following 15 min of exposure to a stimulus rearrangement condition where the phase angle between subject pitch tilt and visual scene translation was 270 deg; statistically significant gain decreases were not observed following exposures either to a condition where the phase angle between subject pitch and scene translation was 90 deg or to a no-stimulus-rearrangement condition. Experiment 2 replicated the 270-deg-phase condition from Experiment 1 and extended the exposure duration from 30 to 45 min. Statistically significant additional changes in CVEMG associated with the increased exposure duration were not observed. The adaptation time constant estimated fram the combined data from Experiments 1 and 2 was 29 min.

CoNNeCT Antenna Positioning System Dynamic Simulator Modal Model Correlation

NASA Technical Reports Server (NTRS)

Jones, Trevor M.; McNelis, Mark E.; Staab, Lucas D.; Akers, James C.; Suarez, Vicente J.

2012-01-01

The National Aeronautics and Space Administration (NASA) developed an on-orbit, adaptable, Software Defined Radios (SDR)/Space Telecommunications Radio System (STRS)-based testbed facility to conduct a suite of experiments to advance technologies, reduce risk, and enable future mission capabilities on the International Space Station (ISS). The Communications, Navigation, and Networking reConfigurable Testbed (CoNNeCT) Project will provide NASA, industry, other Government agencies, and academic partners the opportunity to develop and field communications, navigation, and networking technologies in both the laboratory and space environment based on reconfigurable, software-defined radio platforms and the STRS Architecture. The CoNNeCT Payload Operations Nomenclature is SCAN Testbed, and this nomenclature will be used in all ISS integration, safety, verification, and operations documentation. The SCAN Testbed (payload) is a Flight Releasable Attachment Mechanism (FRAM) based payload that will launch aboard the Japanese H-II Transfer Vehicle (HTV) Multipurpose Exposed Pallet (EP-MP) to the International Space Station (ISS), and will be transferred to the Express Logistics Carrier 3 (ELC3) via Extravehicular Robotics (EVR). The SCAN Testbed will operate on-orbit for a minimum of two years.

The pressure ridge distribution in the Arctic Ocean from submarine sonar data

NASA Astrophysics Data System (ADS)

Rodrigues, Joao; Wadhams, Peter

2010-05-01

The profiling of the underside of the sea ice with upward-looking sonars fitted to submarines is the best method of studying the large scale distribution of morphological features such as pressure ridges and leads. We present the statistical analysis of the distributions of pressure ridge spacings and heights, and lead spacings and widths observed during two Arctic cruises by the Royal Navy submarine HMS Tireless in the winters of 2004 and 2007 in which more than 10000km of sea ice draft data were collected. We briefly describe the main characteristics of the full ice draft distribution in the several regions of the Arctic Ocean visited by the submarine and discuss the most significant differences between 2004 and 2007. In the area of heavily ridged ice north of Greenland and Ellesmere Island we found an increase in ridge density (number of ridges per unit track length) accompanied by a decrease in modal ice draft, leaving the mean ice thickness essentially unchanged, between 2004 and 2007. This area is likely to be the only one in the Arctic Ocean where the sea ice thickness may not be in decline. We investigate the causes of this invariance in the context of an Arctic Ocean in transition from a multi-year to a first-year ice cover and discuss its relation with the strengthening of the transpolar drift and consequent accumulation of ice north of Greenland and increase in ice export through Fram Strait. Our analysis shows that the number of deep ridges per km is well described by a Poisson distribution while the corresponding distribution for shallow ridges is more complicated. The tail of the distribution of the pressure ridge heights is approximately a negative exponential, in agreement with similar observations made in previous cruises. We pay special attention to the uncertainties and biases in the measurement of the ice draft. Specifically, we discuss the effects of the finite beamwidth of the single-beam sonars traditionally used in British submarines on the determination of sea ice draft, which may have been underestimated in previous work.

Liver lipase and high-density lipoprotein. Lipoprotein changes after incubation of human serum with rat liver lipase.

PubMed

Groot, P H; Scheek, L M; Jansen, H

1983-05-16

Human sera were incubated with rat liver lipase after inactivation of lecithin:cholesterol acyltransferase, and the changes in serum lipoprotein composition were measured. In the presence of liver lipase serum triacylglycerol and phosphatidylcholine were hydrolyzed. The main changes in the concentrations of these lipids were found in the high-density lipoprotein fraction. Subfractionation of high-density lipoprotein by rate-zonal ultracentrifugation showed a prominent decrease in all constituents of high-density lipoprotein2, a smaller decrease in the 'light' high-density lipoprotein3 and an increase in the 'heavy' high-density lipoprotein3. These data support a concept in which liver lipase is involved in high-density lipoprotein2 phospholipid and triacylglycerol catabolism and suggest that as a result of this action high-density lipoprotein2 is converted into high-density lipoprotein3.

Interpretation of time series (salinity and temperature) layers in North Atlantic from 1950 to 2011

NASA Astrophysics Data System (ADS)

Rubchenia, A.; Popov, A.; Fedorova, A.; Lebedev, N.

2012-04-01

On the basis of long period data series (1950-2011) form various sources (National Oceanographic Data Center (NOAD) (www.nodc.noaa.gov), WOD09 database and data from ARGO project) 10 boxes in North Atlantic were selected. Location of boxes was determined by circulation pattern in North Atlantic and Euro-Arctic Seas. For further analysis two "seasons" was selected: "cold season" (October-May) and "warm season" (June-September). Data verification was made. Analysis of data series clearly show the "Great Salinity Anomaly" (so-called GSA) in 1960-70th, 1980th and 1990th. Trends of salinity and temperature data series were calculated. Spectral analysis allow us to calculate periodicity from 2 to 22 years. Boxes situated in regions with Arctic waters have singularity showed through domination of high frequency oscillation during propagation to South. In Fram Strait salinity fluctuates with periods 9..11 and 20 years, the same period was calculated using temperature data series. In Denmark Strait there are oscillations of temperature with specific period from 4 to 7 years. Range of variability vary. For salinity it is 0.4..4.6 psu, for temperature it is 0.04..5.5C. In salinity data series from boxes with surface Arctic waters noticed clear minimums connected with GSAs. Trends in Denmark Strait and Fram strait in the end of 2000th are negative at different levels. Since 1975 to 2001 salinity near the southern part of Greenland was increased, since 2001 - decreased. But temperature was raised from 0.04 in 1989 to 5.59 in 2010. Thermohaline characteristics of water masses which has Atlantic origin oscillated with period near 20 years. Salinity near Newfoundland was decreased since 2005. In Farrero-Shetland straits salinity trend is positive since at 100m level, Salinity rising from 1970th to 2006 is about 0.3 psu were noticed. Oscillations with period 2..4 years is weak. But at 800m layer salinity oscillations are different, since 1990 there is not significant oscillations at all. Temperature trend at this level is negative since 1950th. Salinity at 100-300 level at Station M area described with negative trend since 1960 to 1993, in both "seasons". Next, up to 2010 salinity is increasing, but in 2011 salinity dramatically decreased. Main oscillations have periods 2..3 years, 4..5 years and 20 years. At 800m level oscillations are very weak. Temperature is increased since 1995 in surface layer and since 2002 in deeper levels. At all levels temperature dramatically decreased after 2010. In central part of Greenland Sea ("Cupola area") dominated oscillations with period 4 years (1950-60th), 5..7 years (1970th) and 9 years (after 1979). In "cold season" oscillation with 11 years traced. Salinity trend is positive at all levels during last 10-15 years. Salinity and temperature were increased at 800m level up to 2006. It could lead to termination of deep water formation. Since 2006 temperature decreased, especially in "cold season". Salinity trend in West Spitsbergen Current is positive since 1996 at surface and sine 1978 at deeper levels. Temperature was increased since 1965 to 2006 in surface layer, but since 2006 in "warm season" temperature is decreasing at all layers. Main oscillations is 4..5 years, 6..7 years and 9..11 years.

Post-glacial variations of sea ice cover and river discharge in the western Laptev Sea (Arctic Ocean) - a high-resolution study over the last 18 ka

NASA Astrophysics Data System (ADS)

Hörner, Tanja; Stein, Ruediger; Fahl, Kirsten

2015-04-01

Here, we provide a high-resolution reconstruction of sea-ice cover variations in the western Laptev Sea, a crucial area in terms of sea-ice production in the Arctic Ocean and a region characterized by huge river discharge. Furthermore, the shallow Laptev Sea was strongly influenced by the post-glacial sea-level rise that should also be reflected in the sedimentary records. The sea Ice Proxy IP25 (Highly-branched mono-isoprenoid produced by sea-ice algae; Belt et al., 2007) was measured in two sediment cores from the western Laptev Sea (PS51/154, PS51/159) that offer a high-resolution composite record over the last 18 ka. In addition, sterols are applied as indicator for marine productivity (brassicasterol, dinosterol) and input of terrigenous organic matter by river discharge into the ocean (campesterol, ß-sitosterol). The sea-ice cover varies distinctly during the whole time period and shows a general increase in the Late Holocene. A maximum in IP25 concentration can be found during the Younger Dryas. This sharp increase can be observed in the whole circumarctic realm (Chukchi Sea, Bering Sea, Fram Strait and Laptev Sea). Interestingly, there is no correlation between elevated numbers of ice-rafted debris (IRD) interpreted as local ice-cap expansions (Taldenkova et al. 2010), and sea ice cover distribution. The transgression and flooding of the shelf sea that occurred over the last 16 ka in this region, is reflected by decreasing terrigenous (riverine) input, reflected in the strong decrease in sterol (ß-sitosterol and campesterol) concentrations. References Belt, S.T., Massé, G., Rowland, S.J., Poulin, M., Michel, C., LeBlanc, B., 2007. A novel chemical fossil of palaeo sea ice: IP25. Organic Geochemistry 38 (1), 16e27. Taldenkova, E., Bauch, H.A., Gottschalk, J., Nikolaev, S., Rostovtseva, Yu., Pogodina, I., Ya, Ovsepyan, Kandiano, E., 2010. History of ice-rafting and water mass evolution at the northern Siberian continental margin (Laptev Sea) during Late Glacial and Holocene times. Quaternary Science Reviews 29 (27-28), 3919-3935.

High-resolution record of last post-glacial variations of sea-ice cover and river discharge in the western Laptev Sea (Arctic Ocean)

NASA Astrophysics Data System (ADS)

Stein, R. H.; Hörner, T.; Fahl, K.

2014-12-01

Here, we provide a high-resolution reconstruction of sea-ice cover variations in the western Laptev Sea, a crucial area in terms of sea-ice production in the Arctic Ocean and a region characterized by huge river discharge. Furthermore, the shallow Laptev Sea was strongly influenced by the post-glacial sea-level rise that should also be reflected in the sedimentary records. The sea Ice Proxy IP25 (Highly-branched mono-isoprenoid produced by sea-ice algae; Belt et al., 2007) was measured in two sediment cores from the western Laptev Sea (PS51/154, PS51/159) that offer a high-resolution composite record over the last 18 ka. In addition, sterols are applied as indicator for marine productivity (brassicasterol, dinosterol) and input of terrigenous organic matter by river discharge into the ocean (campesterol, ß-sitosterol). The sea-ice cover varies distinctly during the whole time period and shows a general increase in the Late Holocene. A maximum in IP25 concentration can be found during the Younger Dryas. This sharp increase can be observed in the whole circumarctic realm (Chukchi Sea, Bering Sea, Fram Strait and Laptev Sea). Interestingly, there is no correlation between elevated numbers of ice-rafted debris (IRD) interpreted as local ice-cap expansions (Taldenkova et al. 2010), and sea ice cover distribution. The transgression and flooding of the shelf sea that occurred over the last 16 ka in this region, is reflected by decreasing terrigenous (riverine) input, reflected in the strong decrease in sterol (ß-sitosterol and campesterol) concentrations. ReferencesBelt, S.T., Massé, G., Rowland, S.J., Poulin, M., Michel, C., LeBlanc, B., 2007. A novel chemical fossil of palaeo sea ice: IP25. Organic Geochemistry 38 (1), 16e27. Taldenkova, E., Bauch, H.A., Gottschalk, J., Nikolaev, S., Rostovtseva, Yu., Pogodina, I., Ya, Ovsepyan, Kandiano, E., 2010. History of ice-rafting and water mass evolution at the northern Siberian continental margin (Laptev Sea) during Late Glacial and Holocene times. Quaternary Science Reviews 29 (27-28), 3919-3935.

Optimization of ISOCS Parameters for Quantitative Non-Destructive Analysis of Uranium in Bulk Form

NASA Astrophysics Data System (ADS)

Kutniy, D.; Vanzha, S.; Mikhaylov, V.; Belkin, F.

2011-12-01

Quantitative calculation of the isotopic masses of fissionable U and Pu is important for forensic analysis of nuclear materials. γ-spectrometry is the most commonly applied tool for qualitative detection and analysis of key radionuclides in nuclear materials. Relative isotopic measurement of U and Pu may be obtained from γ-spectra through application of special software such as MGAU (Multi-Group Analysis for Uranium, LLNL) or FRAM (Fixed-Energy Response Function Analysis with Multiple Efficiency, LANL). If the concentration of U/Pu in the matrix is unknown, however, isotopic masses cannot be calculated. At present, active neutron interrogation is the only practical alternative for non-destructive quantification of fissionable isotopes of U and Pu. An active well coincidence counter (AWCC), an alternative for analyses of uranium materials, has the following disadvantages: 1) The detection of small quantities (≤100 g) of 235U is not possible in many models; 2) Representative standards that capture the geometry, density and chemical composition of the analyzed unknown are required for precise analysis; and 3) Specimen size is severely restricted by the size of the measuring chamber. These problems may be addressed using modified γ-spectrometry techniques based on a coaxial HPGe-detector and ISOCS software (In Situ Object Counting System software, Canberra). We present data testing a new gamma-spectrometry method uniting actinide detection with commonly utilized software, modified for application in determining the masses of the fissionable isotopes in unknown samples of nuclear materials. The ISOCS software, widely used in radiation monitoring, calculates the detector efficiency curve in a specified geometry and range of photon energies. In describing the geometry of the source-detector, it is necessary to clearly describe the distance between the source and the detector, the material and the thickness of the walls of the container, as well as material, density and chemical composition of the matrix of the specimen. Obviously, not all parameters can be characterized when measuring samples of unknown composition or uranium in bulk form. Because of this, and especially for uranium materials, the IAEA developed an ISOCS optimization procedure. The target values for the optimization are Μmatrixfixed, the matrix mass determined by weighing with a known mass container, and Εfixed, the 235U enrichment, determined by MGAU. Target values are fitted by varying the matrix density (ρ), and the concentration of uranium in the matrix of the unknown (w). For each (ρi, wi), an efficiency curve is generated, and the masses of uranium isotopes, Μ235Ui and Μ238Ui, determined using spectral activity data and known specific activities for U. Finally, fitted parameters are obtained for Μmatrixi = Μmatrixfixed ± 1σ, Εi = Εfixed ± 1σ, as well as important parameters (ρi, wi, Μ235Ui, Μ238Ui, ΜUi). We examined multiple forms of uranium (powdered, pressed, and scrap UO2 and U3O8) to test this method for its utility in accurately identifying the mass and enrichment of uranium materials, and will present the results of this research.

Experimental study of high density foods for the Space Operations Center

NASA Technical Reports Server (NTRS)

Ahmed, S. M.

1981-01-01

The experimental study of high density foods for the Space Operations Center is described. A sensory evaluation of the high density foods was conducted first to test the acceptability of the products. A shelf-life study of the high density foods was also conducted for three different time lengths at three different temperatures. The nutritional analysis of the high density foods is at present incomplete.

Alkenone-based reconstructions reveal four-phase Holocene temperature evolution for High Arctic Svalbard

NASA Astrophysics Data System (ADS)

van der Bilt, Willem G. M.; D'Andrea, William J.; Bakke, Jostein; Balascio, Nicholas L.; Werner, Johannes P.; Gjerde, Marthe; Bradley, Raymond S.

2018-03-01

Situated at the crossroads of major oceanic and atmospheric circulation patterns, the Arctic is a key component of Earth's climate system. Compounded by sea-ice feedbacks, even modest shifts in the region's heat budget drive large climate responses. This is highlighted by the observed amplified response of the Arctic to global warming. Assessing the imprint and signature of underlying forcing mechanisms require paleoclimate records, allowing us to expand our knowledge beyond the short instrumental period and contextualize ongoing warming. However, such datasets are scarce and sparse in the Arctic, limiting our ability to address these issues. Here, we present two quantitative Holocene-length paleotemperature records from the High Arctic Svalbard archipelago, situated in the climatically sensitive Arctic North Atlantic. Temperature estimates are based on U37K unsaturation ratios from sediment cores of two lakes. Our data reveal a dynamic Holocene temperature evolution, with reconstructed summer lake water temperatures spanning a range of ∼6-8 °C, and characterized by four phases. The Early Holocene was marked by an early onset (∼10.5 ka cal. BP) of insolation-driven Hypsithermal conditions, likely compounded by strengthening oceanic heat transport. This warm interval was interrupted by cooling between ∼10.5-8.3 ka cal. BP that we attribute to cooling effects from the melting Northern Hemisphere ice sheets. Temperatures declined throughout the Middle Holocene, following a gradual trend that was accentuated by two cooling steps between ∼7.8-7 ka cal. BP and around ∼4.4-4.3 ka cal. BP. These transitions coincide with a strengthening influence of Arctic water and sea-ice in the adjacent Fram Strait. During the Late Holocene (past 4 ka), temperature change decoupled from the still-declining insolation, and fluctuated around comparatively cold mean conditions. By showing that Holocene Svalbard temperatures were governed by an alternation of forcings, this study improves our understanding of Arctic climate dynamics.

A hybrid electrochemical device based on a synergetic inner combination of Li ion battery and Li ion capacitor for energy storage.

PubMed

Zheng, Jun-Sheng; Zhang, Lei; Shellikeri, Annadanesh; Cao, Wanjun; Wu, Qiang; Zheng, Jim P

2017-02-07

Li ion battery (LIB) and electrochemical capacitor (EC) are considered as the most widely used energy storage systems (ESSs) because they can produce a high energy density or a high power density, but it is a huge challenge to achieve both the demands of a high energy density as well as a high power density on their own. A new hybrid Li ion capacitor (HyLIC), which combines the advantages of LIB and Li ion capacitor (LIC), is proposed. This device can successfully realize a potential match between LIB and LIC and can avoid the excessive depletion of electrolyte during the charge process. The galvanostatic charge-discharge cycling tests reveal that at low current, the HyLIC exhibits a high energy density, while at high current, it demonstrates a high power density. Ragone plot confirms that this device can make a synergetic balance between energy and power and achieve a highest energy density in the power density range of 80 to 300 W kg -1 . The cycle life test proves that HyLIC exhibits a good cycle life and an excellent coulombic efficiency. The present study shows that HyLIC, which is capable of achieving a high energy density, a long cycle life and an excellent power density, has the potential to achieve the winning combination of a high energy and power density.

A hybrid electrochemical device based on a synergetic inner combination of Li ion battery and Li ion capacitor for energy storage

PubMed Central

Zheng, Jun-Sheng; Zhang, Lei; Shellikeri, Annadanesh; Cao, Wanjun; Wu, Qiang; Zheng, Jim P.

2017-01-01

Li ion battery (LIB) and electrochemical capacitor (EC) are considered as the most widely used energy storage systems (ESSs) because they can produce a high energy density or a high power density, but it is a huge challenge to achieve both the demands of a high energy density as well as a high power density on their own. A new hybrid Li ion capacitor (HyLIC), which combines the advantages of LIB and Li ion capacitor (LIC), is proposed. This device can successfully realize a potential match between LIB and LIC and can avoid the excessive depletion of electrolyte during the charge process. The galvanostatic charge-discharge cycling tests reveal that at low current, the HyLIC exhibits a high energy density, while at high current, it demonstrates a high power density. Ragone plot confirms that this device can make a synergetic balance between energy and power and achieve a highest energy density in the power density range of 80 to 300 W kg−1. The cycle life test proves that HyLIC exhibits a good cycle life and an excellent coulombic efficiency. The present study shows that HyLIC, which is capable of achieving a high energy density, a long cycle life and an excellent power density, has the potential to achieve the winning combination of a high energy and power density. PMID:28169329

The Effect of a Three-Week Adaptation to a Low Carbohydrate/High Fat Diet on Metabolism and Cognitive Performance

DTIC Science & Technology

1990-04-11

triglycerides , insulin, glucagon, cholesterol (total, high density lipoprotein ( HDL ), low density lipoprotein (LDL)I, cortisol, thyroid hormone...thyroid function, triglycerides , total cholesterol , high density lipoprotein cholesterol ( HDL ), low density lipoprotein cholesterol (LDL), ketone... density lipoprotein ( HDL ) fraction of cholesterol was

Densities and temperatures in the polar thermosphere

NASA Technical Reports Server (NTRS)

Gardner, L. J.

1977-01-01

The atomic oxygen density at 120 km, the 630 nm airglow temperature, the helium density at 300 km and the molecular nitrogen density near 400 km were examined as functions of geomagnetic latitude, geomagnetic time, season and magnetic activity level. The long-term averages of these quantities were examined so as to provide a baseline of these thermospheric parameters from which future studies may be made for comparison. The hours around magnetic noon are characterized by low temperatures, high 0 and He densities, and median nitrogen densities. The pre-midnight hours exhibit high temperatures, high He density, low nitrogen density and median 0 densities. The post-midnight sector shows low 0 and He densities, median temperatures and high nitrogen densities. These results are compared to recent models and observations and are discussed with respect to their causes due to divergence of the wind field and energy deposition in the thermosphere.

Silicon-Based Lithium-Ion Capacitor for High Energy and High Power Application

NASA Technical Reports Server (NTRS)

Wu, James J.; Demattia, Brianne; Loyselle, Patricia; Reid, Concha; Kohout, Lisa

2017-01-01

Si-based Li-ion capacitor has been developed and demonstrated. The results show it is feasible to improve both power density and energy density in this configuration. The applied current density impacts the power and energy density: low current favors energy density while high current favors power density. Active carbon has a better rate capability than Si. Next StepsFuture Directions. Si electrode needs to be further studied and improved. Further optimization of SiAC ratio and evaluation of its impact on energy density and power density.

Evaluation of Arctic Sea Ice Thickness Simulated by AOMIP Models

NASA Technical Reports Server (NTRS)

Johnson, Mark; Proshutinsky, Andrey; Aksenov, Yevgeny; Nguyen, An T.; Lindsay, Ron; Haas, Christian; Zhang, Jinlun; Diansky, Nimolay; Kwok, Ron; Maslowski, Wieslaw;

Initial Results from On-Orbit Testing of the Fram Memory Test Experiment on the Fastsat Micro-Satellite

NASA Technical Reports Server (NTRS)

MacLeond, Todd C.; Sims, W. Herb; Varnavas,Kosta A.; Ho, Fat D.

2011-01-01

The Memory Test Experiment is a space test of a ferroelectric memory device on a low Earth orbit satellite that launched in November 2010. The memory device being tested is a commercial Ramtron Inc. 512K memory device. The circuit was designed into the satellite avionics and is not used to control the satellite. The test consists of writing and reading data with the ferroelectric based memory device. Any errors are detected and are stored on board the satellite. The data is sent to the ground through telemetry once a day. Analysis of the data can determine the kind of error that was found and will lead to a better understanding of the effects of space radiation on memory systems. The test is one of the first flight demonstrations of ferroelectric memory in a near polar orbit which allows testing in a varied radiation environment. The initial data from the test is presented. This paper details the goals and purpose of this experiment as well as the development process. The process for analyzing the data to gain the maximum understanding of the performance of the ferroelectric memory device is detailed.

Late Eocene to present isotopic (Sr-Nd-Pb) and geochemical evolution of sediments from the Lomonosov Ridge, Arctic Ocean: Implications for continental sources and linkage with the North Atlantic Ocean

NASA Astrophysics Data System (ADS)

Stevenson, Ross; Poirier, André; Véron, Alain; Carignan, Jean; Hillaire-Marcel, Claude

2015-09-01

New geochemical and isotopic (Sr, Nd, Pb) data are presented for a composite sedimentary record encompassing the past 50 Ma of history of sedimentation on the Lomonosov Ridge in the Arctic Ocean. The sampled sediments encompass the transition of the Arctic basin from an enclosed anoxic basin to an open and ventilated oxidized ocean basin. The transition from anoxic basin to open ventilated ocean is accompanied by at least three geochemical and isotopic shifts and an increase in elements (e.g., K/Al) controlled by detrital minerals highlighting significant changes in sediment types and sources. The isotopic compositions of the sediments prior to ventilation are more variable but indicate a predominance of older crustal contributions consistent with sources from the Canadian Shield. Following ventilation, the isotopic compositions are more stable and indicate an increased contribution from younger material consistent with Eurasian and Pan-African crustal sources. The waxing and waning of these sources in conjunction with the passage of water through Fram Strait underlines the importance of the exchange of water mass between the Arctic and North Atlantic Oceans.

Plasma-Assisted Dry Etching of Ferroelectric Capacitor Modules and Application to a 32M Ferroelectric Random Access Memory Devices with Submicron Feature Sizes

NASA Astrophysics Data System (ADS)

Lee, Sang-Woo; Joo, Suk-Ho; Cho, Sung Lae; Son, Yoon-Ho; Lee, Kyu-Mann; Nam, Sang-Don; Park, Kun-Sang; Lee, Yong-Tak; Seo, Jung-Suk; Kim, Young-Dae; An, Hyeong-Geun; Kim, Hyoung-Joon; Jung, Yong-Ju; Heo, Jang-Eun; Lee, Moon-Sook; Park, Soon-Oh; Chung, U-In; Moon, Joo-Tae

2002-11-01

In the manufacturing of a 32M ferroelectric random access memory (FRAM) device on the basis of 0.25 design rule (D/R), one of the most difficult processes is to pattern a submicron capacitor module while retaining good ferroelectric properties. In this paper, we report the ferroelectric property of patterned submicron capacitor modules with a stack height of 380 nm, where the 100 nm-thick Pb(Zr, Ti)O3 (PZT) films were prepared by the sol-gel method. After patterning, overall sidewall slope was approximately 70° and cell-to-cell node separation was made to be 80 nm to prevent possible twin-bit failure in the device. Finally, several heat treatment conditions were investigated to retain the ferroelectric property of the patterned capacitor. It was found that rapid thermal processing (RTP) treatment yields better properties than conventional furnace annealing. This result is directly related to the near-surface chemistry of the PZT films, as confirmed by X-ray photoelectron spectroscopy (XPS) analysis. The resultant switching polarization value of the submicron capacitor was approximately 30 μC/cm2 measured at 3 V.

Pathways of Atlantic Waters in the Nordic seas: locally eddy-permitting ocean simulation in a global setup

NASA Astrophysics Data System (ADS)

Wekerle, C.; Wang, Q.; Danilov, S.; Jung, T.; Schourup-Kristensen, V.

2016-02-01

Atlantic Water (AW) passes through the Nordic Seas and enters the Arctic Ocean through the shallow Barents Sea and the deep Fram Strait. Since the 1990's, observations indicate a series of anomalously warm pulses of Atlantic Water that entered the Arctic Ocean. In fact, poleward oceanic heat transport may even increase in the future, which might have implications for the heat uptake in the Arctic Ocean as well as for the sea ice cover. The ability of models to faithfully simulate the pathway of the AW and accompanying dynamics is thus of high climate relevance. In this study, we explore the potential of a global multi-resolution sea ice-ocean model with a locally eddy-permitting resolution (around 4.5 km) in the Nordic seas region and Arctic Ocean in improving the representation of Atlantic Water inflow, and more broadly, the dynamics of the circulation in the Northern North Atlantic and Arctic. The simulation covers the time period 1969-2009. We find that locally increased resolution improves the localization and thickness of the Atlantic Water layer in the Nordic seas, compared with a 20 km resolution reference simulation. In particular, the inflow of Atlantic Waters through the Greenland Scotland Ridge and the narrow branches of the Norwegian Atlantic Current can be realistically represented. Lateral spreading due to simulated eddies essentially reduces the bias in the surface temperature. In addition, a qualitatively good agreement of the simulated eddy kinetic energy field with observations can be achieved. This study indicates that a substantial improvement in representing local ocean dynamics can be reached through the local refinement, which requires a rather moderate computational effort. The successful model assessment allows us to further investigate the variability and mechanisms behind Atlantic Water transport into the Arctic Ocean.

The smallest Gliders in the Ocean- Temperature Recordings from Pteropods using SIMS

NASA Astrophysics Data System (ADS)

Keul, N.; Orland, I. J.; Valley, J. W.; Kozdon, R.; deMenocal, P. B.

2016-02-01

During the last few decades, the development, refinement and application of geochemical methods have lead to the establishment of new proxies to estimate global change. The oxygen isotope composition of carbonate shells formed by marine organisms is a widely used proxy for past ocean temperatures. Secondary ion mass spectrometry (SIMS) is a high spatial-resolution in situ technique, allowing oxygen isotope measurements on very small samples (down to 3 μm spot size). Pteropods are pelagic mollusks, producing shells made out of aragonite, which is more soluble than calcite in seawater, making them one of the first responders to climate change. They calcify closely at the aragonite- seawater equilibrium and are therefor ideal candidates to reconstruct temperatures based on their d18O. The oxygen isotopic composition of pteropod shells from sediment traps, net tows and a culture study from the Fram Strait will be presented. Specimens travelled in the Westspitsbergen Current prior to sinking into the sediment. During this transport specimens continue to grow, sequentially adding aragonite to the shell. We show that when using traditional (whole shell) δ18O measurements, the isotopic signatures of whole shells reflect the latitudinal gradient. Combining this with SIMS-derived δ18O measurements on individual shell parts, however, reveals that this is only half the story: Comparing δ18O of earlier (produced further South) and later shell parts (produced further North) shows that pteropods calcify in sequentially shallower water depths, overriding the latitudinal South to North temperature gradient. Combining traditional and novel δ18O measurements can potentially not only allow the reconstruction of temperature/ global warming, but also to assess ecological key parameters, such as habitat depth, at the same time.

High current density cathode for electrorefining in molten electrolyte

DOEpatents

Li, Shelly X.

2010-06-29

A high current density cathode for electrorefining in a molten electrolyte for the continuous production and collection of loose dendritic or powdery deposits. The high current density cathode eliminates the requirement for mechanical scraping and electrochemical stripping of the deposits from the cathode in an anode/cathode module. The high current density cathode comprises a perforated electrical insulated material coating such that the current density is up to 3 A/cm.sup.2.

High-resolution Ceres HAMO Atlas derived from Dawn FC Images

NASA Astrophysics Data System (ADS)

Roatsch, T.; Kersten, E.; Matz, K. D.; Preusker, F.; Scholten, F.; Jaumann, R.; Raymond, C. A.; Russell, C. T.

2015-12-01

Introduction: NASA's Dawn spacecraft will orbit the dwarf planet Ceres in August and September 2015 in HAMO (High Altitude Mapping Orbit) with an altitude of about 1,500 km to characterize for instance the geology, topography, and shape of Ceres before it will be transferred to the lowest orbit. One of the major goals of this mission phase is the global mapping of Ceres. Data: The Dawn mission is equipped with a fram-ing camera (FC). The framing camera will take about 2600 clear filter images with a resolution of about 120 m/pixel and different viewing angles and different illumination conditions. Data Processing: The first step of the processing chain towards the cartographic products is to ortho-rectify the images to the proper scale and map projec-tion type. This process requires detailed information of the Dawn orbit and attitude data and of the topography of the target. Both, improved orientation and high-resolution shape models, are provided by stereo processing of the HAMO dataset. Ceres' HAMO shape model is used for the calculation of the ray intersection points while the map projection itself will be done onto a reference sphere for Ceres. The final step is the controlled mosaicking of all nadir images to a global mosaic of Ceres, the so called basemap. Ceres map tiles: The Ceres atlas will be produced in a scale of 1:750,000 and will consist of 15 tiles that conform to the quadrangle schema for small planets and medium size Icy satellites. A map scale of 1:750,000 guarantees a mapping at the highest availa-ble Dawn resolution in HAMO. Nomenclature: The Dawn team proposed to the International Astronomical Union (IAU) to use the names of gods and goddesses of agriculture and vege-tation from world mythology as names for the craters. This proposal was accepted by the IAU and the team proposed names for geological features to the IAU based on the HAMO mosaic. These feature names will be applied to the map tiles.

Variation in food availability mediate the impact of density on cannibalism, growth, and survival in larval yellow spotted mountain newts (Neurergus microspilotus): Implications for captive breeding programs.

PubMed

Vaissi, Somaye; Sharifi, Mozafar

2016-11-01

In this study, we examined cannibalistic behavior, growth, metamorphosis, and survival in larval and post-metamorph endangered yellow spotted mountain newts Neurergus microspilotus hatched and reared in a captive breeding facility. We designed a 2 × 2 factorial experiment, crossing two levels of food with two levels of density including high food/high density, high food/low density, low food/high density, and low food/low density. The level of cannibalistic behavior (including the loss of fore and hind limbs, missing toes, tail, gills, body damage, and whole body consumption) changed as the larvae grew, from a low level during the first 4 weeks, peaking from weeks 7 to 12, and then dropped during weeks 14-52. Both food level and density had a significant effect on cannibalism. The highest frequency of cannibalism was recorded for larvae reared in the low food/high density and lowest in high food/low density treatments. Growth, percent of larval metamorphosed, and survival were all highest in the high food/low density and lowest in low food/high density treatment. Food level had a significant effect on growth, metamorphosis, and survival. However, the two levels of density did not influence growth and metamorphosis but showed a significant effect on survival. Similarly, combined effects of food level and density showed significant effects on growth, metamorphosis, and survival over time. Information obtained from current experiment could improve productivity of captive breeding facilities to ensure the release of adequate numbers of individuals for reintroduction programs. Zoo Biol. 35:513-521, 2016. © 2016 The Authors. Zoo Biology published by Wiley Periodicals, Inc. © 2016 The Authors. Zoo Biology published by Wiley Periodicals, Inc.

Effects of low-dose monophasic levonorgestrel with ethinyl estradiol preparation on serum lipid levels: A twenty-four month clinical trial.

PubMed

Young, R L; DelConte, A

1999-11-01

The aim of this 24-cycle study was to evaluate the effects on serum lipid concentrations of an oral contraceptive preparation containing 100 microg levonorgestrel and 20 microg ethinyl estradiol. Forty-two healthy women were enrolled in a study designed to evaluate the effects on serum lipid concentrations of an oral contraceptive containing 100 microg levonorgestrel and 20 microg ethinyl estradiol. Lipid data were evaluated for 28 women who completed 24 cycles of treatment with a preparation of 100 microg levonorgestrel with 20 microg ethinyl estradiol for 21 days followed by placebo for 7 days. Concentrations of triglycerides, total cholesterol, high-density lipoprotein cholesterol, high-density lipoprotein cholesterol subfractions 2 and 3, low-density lipoprotein cholesterol, and apolipoproteins A-I and B were analyzed. Mean percentage changes from baseline were tested for significance by means of paired Student t tests. Total cholesterol, high-density lipoprotein cholesterol, high-density lipoprotein subfraction 2, and apolipoprotein A-I concentrations were not significantly changed from baseline. Neither was the ratio of high-density lipoprotein subfraction 2 to high-density lipoprotein subfraction 3. Mean percentage increases in concentrations of triglyceride, high-density lipoprotein subfraction 3, apolipoprotein B, and low-density lipoprotein cholesterol and increases in the ratios of total cholesterol to high-density lipoprotein cholesterol, low-density lipoprotein cholesterol to high-density lipoprotein cholesterol, and apolipoprotein B to apolipoprotein A-I were significant (P <.05) at >/=1 cycle. By cycle 24, however, only the concentration of high-density lipoprotein subfraction 3 remained significantly elevated. Changes in the plasma lipid profiles among women receiving monophasic 100 microg levonorgestrel with 20 microg ethinyl estradiol were similar to those seen with other low-dose oral contraceptives, but by cycle 24 only 1 of 7 mean values remained significantly different from baseline.

Effects of high density on spacing behaviour and reproduction in Akodon azarae: A fencing experiment

NASA Astrophysics Data System (ADS)

Ávila, Belén; Bonatto, Florencia; Priotto, José; Steinmann, Andrea R.

2016-01-01

We studied the short term spacing behavioural responses of Pampean grassland mouse (Akodon azarae) with regard to population density in four 0.25 ha enclosures (two control and two experimental) in the 2011 breeding season. Based on the hypothesis that A. azarae breeding females exhibit spacing behaviour, and breeding males show a fusion spatial response, we tested the following predictions: (1) home range size and intrasexual overlap degree of females are independent of population density values; (2) at high population density, home range size of males decreases and the intrasexual home range overlap degree increases. To determine if female reproductive success decreases at high population density, we analyzed pregnancy rate, size and weight of litters, and period until fecundation in both low and high enclosure population density. We found that both males and females varied their home range size in relation to population density. Although male home ranges were always bigger than those of females in populations with high density, home range sizes of both sexes decreased. Females kept exclusive home ranges independent of density values meanwhile males decreased home range overlap in high breeding density populations. Although females produced litters of similar size in both treatments, weight of litter, pregnant rate and period until fecundation varied in relation to population density. Our results did not support the hypothesis that at high density females of A. azarae exhibit spacing behaviour neither that males exhibit a fusion spatial response.

Electron dynamics in high energy density plasma bunch generation driven by intense picosecond laser pulse

NASA Astrophysics Data System (ADS)

Li, M.; Yuan, T.; Xu, Y. X.; Luo, S. N.

2018-05-01

When an intense picosecond laser pulse is loaded upon a dense plasma, a high energy density plasma bunch, including electron bunch and ion bunch, can be generated in the target. We simulate this process through one-dimensional particle-in-cell simulation and find that the electron bunch generation is mainly due to a local high energy density electron sphere originated in the plasma skin layer. Once generated the sphere rapidly expands to compress the surrounding electrons and induce high density electron layer, coupled with that, hot electrons are efficiently triggered in the local sphere and traveling in the whole target. Under the compressions of light pressure, forward-running and backward-running hot electrons, a high energy density electron bunch generates. The bunch energy density is as high as TJ/m3 order of magnitude in our conditions, which is significant in laser driven dynamic high pressure generation and may find applications in high energy density physics.

Zooplankton in the Arctic outflow

NASA Astrophysics Data System (ADS)

Soloviev, K. A.; Dritz, A. V.; Nikishina, A. B.

2009-04-01

Climate changes in the Arctic cause the changes in the current system that may have cascading effect on the structure of plankton community and consequently on the interlinked and delicately balanced food web. Zooplankton species are by definition incapable to perform horizontal moving. Their transport is connected with flowing water. There are zooplankton species specific for the definite water masses and they can be used as markers for the different currents. That allows us to consider zooplankton community composition as a result of water mixing in the studied area. Little is known however about the mechanisms by which spatial and temporal variability in advection affect dynamics of local populations. Ice conditions are also very important in the function of pelagic communities. Melting time is the trigger to all "plankton blooming" processes, and the duration of ice-free conditions determines the food web development in the future. Fram Strait is one of the key regions for the Arctic: the cold water outflow comes through it with the East Greenland Current and meets warm Atlantic water, the West Spitsbergen Current, producing complicated hydrological situation. During 2007 and 2008 we investigated the structure functional characteristics of zooplankton community in the Fram Strait region onboard KV "Svalbard" (April 2007, April and May 2008) and RV "Jan Mayen" (May 2007, August 2008). This study was conducted in frame of iAOOS Norway project "Closing the loop", which, in turn, was a part of IPY. During this cruises multidisciplinary investigations were performed, including sea-ice observations, CTD and ADCP profiling, carbon flux, nutrients and primary production measurements, phytoplankton sampling. Zooplankton was collected with the Hydro-Bios WP2 net and MultiNet Zooplankton Sampler, (mouth area 0.25 m2, mesh size 180 um).Samples were taken from the depth strata of 2000-1500, 1500-1000, 1000-500,500-200, 200-100, 100-60, 60-30, 30-0 m. Gut fluorescence content were measured in dominant species to investigate effect of Chl a concentration and phytoplankton composition on ingestion rate. Egg production experiments were carried out under different food conditions. Rare deep water zooplankton species were also investigated to increase our knowledge in the Arctic biodiversity. Copepods Calanus finmarchicus is known as a marker of the Atlantic water mass, Calanus glacialis and Calanus hyperboreus, vice versa, are the coldwater Arctic species. In our study we investigated three Calanus species distribution and analyzed their ecological status. Changes in zooplankton composition results in the alteration of energy transfer within the pelagic food web ("cold" and "warm" scenarios) with potential consequences for growth and survival of seabirds Little Auk (Alle alle) and Black-legged kittiwake (Rissa tridactyla). We discuss the advection effect on the zooplankton community, compare the population development phases with phytoplankton bloom phases (match-mismatch), estimate grazing impact on phytoplankton community and consider different life strategies for the three different Calanus species.

Late Quaternary sea-ice history of northern Fram Strait/Arctic Ocean

NASA Astrophysics Data System (ADS)

Kremer, Anne; Stein, Rüdiger; Fahl, Kirsten; Matthießen, Jens; Forwick, Matthias; O'Regan, Matt

2016-04-01

One of the main characteristics of the Arctic Ocean is its seasonal to perennial sea-ice cover. Variations of sea-ice conditions affect the Earth's albedo, primary production, rate of deep-water etc.. During the last decades, a drastic decrease in sea ice has been recorded, and the causes of which, i.e., natural vs. anthropogenic forcings, and their relevance within the global climate system, are subject of intense scientific and societal debate. In this context, records of past sea-ice conditions going beyond instrumental records are of major significance. These records may help to better understand the processes controlling natural sea-ice variability and to improve models for forecasts of future climatic conditions. During RV Polarstern Cruise PS92 in summer 2015, a 860 cm long sediment core (PS92/039-2) was recovered from the eastern flank of Yermak Plateau north of the Svalbard archipelago (Peeken, 2015). Based on a preliminary age model, this sediment core probably represents the time interval from MIS 6 to MIS 1. This core, located close to the modern summer ice edge, has been selected for reconstruction of past Arctic sea-ice variability based on specific biomarkers. In this context, we have determined the ice-algae-derived sea-ice proxy IP25 (Belt et al., 2007), in combination with other biomarkers indicative for open-water conditions (cf., Müller et al., 2009, 2011). Furthermore, organic carbon fluxes were differentiated using specific biomarkers indicative for marine primary production (brassicasterol, dinosterol) and terrigenous input (campesterol, β-sitosterol). In this poster, preliminary results of our organic-geochemical and sedimentological investigations are presented. Distinct fluctuations of these biomarkers indicate several major, partly abrupt changes in sea-ice cover in the Yermak Plateau area during the late Quaternary. These changes are probably linked to changes in the inflow of Atlantic Water along the western coastline of Svalbard into the Arctic Ocean. Furthermore, the repetitive advance and retreat of the Svalbard Barents Sea Ice Sheet might have influenced the terrigenous input and the environmental setting north of Svalbard, as reflected in the sediment composition of Core PS92/039-2. References Belt, S.T., Massé, G., Rowland, S.J., Poulin, M., Michel, C., LeBlanc, B., 2007. A novel chemical fossil of paleo sea ice: IP25. Organic Geochemistry 38, 16-27. Müller, J., Massé, G., Stein, R., Belt, S.T., 2009. Variability of sea-ice conditions in the Fram Strait over the past 30,000 years. Nature Geoscience 2 (11), 772-776. Müller, J., Wagner, A., Fahl, K., Stein, R., Prange, M., Lohmann, G., 2011. Towards quantitative sea ice reconstructions in the northern North Atlantic: a combined biomarker and numerical modelling approach. Earth and Planetary Science Letters 306 (3,4), 137-148. Peeken, I. (Ed.), 2015. Cruise report of Arctic Expedition PS92: TRANSSIZ Cruise from Bremerhaven to Longyearbyen (19.05.2015 - 28.06.2015), in preparation.

Activation of lipoprotein lipase by lipoprotein fractions of human serum.

PubMed

Bier, D M; Havel, R J

1970-11-01

Triglycerides in fat emulsions are hydrolyzed by lipoprotein lipase only when they are "activated" by serum lipoproteins. The contribution of different lipoprotein fractions to hydrolysis of triglycerides in soybean oil emulsion was assessed by determining the quantity of lipoprotein fraction required to give half-maximal hydrolysis. Most of the activator property of whole serum from normolipidemic, postabsorptive subjects was in high density lipoproteins. Low density lipoproteins and serum from which all lipoprotein classes were removed had little or no activity. Also, little activator was present in guinea pig serum or in very low density poor serum from an individual with lecithin:cholesterol acyltransferase deficiency, both of which are deficient in high density lipoproteins. Human very low density lipoproteins are potent activators and are much more active than predicted from their content of high density lipoprotein-protein. Per unit weight of protein, very low density lipoproteins had 13 times the activity of high density lipoproteins. These observations suggest that one or more of the major apoproteins of very low density lipoproteins, present as a minor constituent of high density lipoproteins, may be required for the activation process.

High-power-density, high-energy-density fluorinated graphene for primary lithium batteries

NASA Astrophysics Data System (ADS)

Zhong, Guiming; Chen, Huixin; Huang, Xingkang; Yue, Hongjun; Lu, Canzhong

2018-03-01

Li/CFx is one of the highest-energy-density primary batteries; however, poor rate capability hinders its practical applications in high-power devices. Here we report a preparation of fluorinated graphene (GFx) with superior performance through a direct gas fluorination. We find that the so-called “semi-ionic” C-F bond content in all C-F bonds presents a more critical impact on rate performance of the GFx in comparison with sp2 C content in the GFx, morphology, structure, and specific surface area of the materials. The rate capability remains excellent before the semi-ionic C-F bond proportion in the GFx decreases. Thus, by optimizing semi-ionic C-F content in our GFx, we obtain the optimal x of 0.8, with which the GF0.8 exhibits a very high energy density of 1073 Wh kg-1 and an excellent power density of 21460 W kg-1 at a high current density of 10 A g-1. More importantly, our approach opens a new avenue to obtain fluorinated carbon with high energy densities without compromising high power densities.

All 2D materials as electrodes for high power hybrid energy storage applications

NASA Astrophysics Data System (ADS)

Kato, Keiko; Sayed, Farheen N.; Babu, Ganguli; Ajayan, Pulickel M.

2018-04-01

Achieving both high energy and power densities from energy storage devices is a core strategy to meet the increasing demands of high performance portable electronics and electric transportation systems. Li-ion capacitor is a promising hybrid technology that strategically exploits high energy density from a Li-ion battery electrode and high power density from a supercapacitor electrode. However, the performance and safety of hybrid devices are still major concerns due to the use of graphite anodes which form passivation layers with organic electrolytes at lower potentials. Here, we explore 2D nanosheets as both anode and cathode electrodes to build a high power system without compromising energy density. Owing to the high electrical conductivity and multivalent redox activity at higher potentials, the Li-ion intercalation electrode is capable of maintaining large energy density at higher current rates with less safety risk than conventional systems. Hybrid devices consisting of all in all 2D electrodes deliver energy density as high as 121 Wh g-1 (at 240 W kg-1) and retains 29 Wh g-1 at high power density of 3600 W kg-1.

Nonlinear dielectric thin films for high-power electric storage with energy density comparable with electrochemical supercapacitors.

PubMed

Yao, Kui; Chen, Shuting; Rahimabady, Mojtaba; Mirshekarloo, Meysam Sharifzadeh; Yu, Shuhui; Tay, Francis Eng Hock; Sritharan, Thirumany; Lu, Li

2011-09-01

Although batteries possess high energy storage density, their output power is limited by the slow movement of charge carriers, and thus capacitors are often required to deliver high power output. Dielectric capacitors have high power density with fast discharge rate, but their energy density is typically much lower than electrochemical supercapacitors. Increasing the energy density of dielectric materials is highly desired to extend their applications in many emerging power system applications. In this paper, we review the mechanisms and major characteristics of electric energy storage with electrochemical supercapacitors and dielectric capacitors. Three types of in-house-produced ferroic nonlinear dielectric thin film materials with high energy density are described, including (Pb(0.97)La(0.02))(Zr(0.90)Sn(0.05)Ti(0.05))O(3) (PLZST) antiferroelectric ceramic thin films, Pb(Zn(1/3)Nb(2/3))O(3-)Pb(Mg(1/3)Nb(2/3))O(3-)PbTiO(3) (PZN-PMN-PT) relaxor ferroelectric ceramic thin films, and poly(vinylidene fluoride) (PVDF)-based polymer blend thin films. The results showed that these thin film materials are promising for electric storage with outstandingly high power density and fairly high energy density, comparable with electrochemical supercapacitors.

Electrode/Dielectric Strip For High-Energy-Density Capacitor

NASA Technical Reports Server (NTRS)

Yen, Shiao-Ping S.

1994-01-01

Improved unitary electrode/dielectric strip serves as winding in high-energy-density capacitor in pulsed power supply. Offers combination of qualities essential for high energy density: high permittivity of dielectric layers, thinness, and high resistance to breakdown of dielectric at high electric fields. Capacitors with strip material not impregnated with liquid.

76 FR 80993 - Self-Regulatory Organizations; The NASDAQ Stock Market LLC; Notice of Filing and Immediate...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-27

... option of obtaining several cabinet sizes and power densities. The co-located customer may obtain a half cabinet, a low density cabinet, a medium density cabinet, a medium-high density cabinet and a high density...-location customer may obtain more power by choosing a combination of lower power density cabinets. However...

76 FR 80995 - Self-Regulatory Organizations; NASDAQ OMX PHLX LLC; Notice of Filing and Immediate Effectiveness...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-27

... cabinet sizes and power densities. The co-located customer may obtain a half cabinet, a low density cabinet, a medium density cabinet, a medium-high density cabinet and a high density cabinet. Each cabinet... obtain more power by choosing a combination of lower power density cabinets. However, the Exchange is...

76 FR 80996 - Self-Regulatory Organizations; NASDAQ OMX BX, Inc.; Notice of Filing and Immediate Effectiveness...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-27

... power densities. The co-located customer may obtain a half cabinet, a low density cabinet, a medium density cabinet, a medium-high density cabinet and a high density cabinet.\\3\\ Each cabinet may vary in... by choosing a combination of lower power density cabinets. However, the Exchange is providing a...

Density-dependent natural selection and trade-offs in life history traits.

PubMed

Mueller, L D; Guo, P Z; Ayala, F J

1991-07-26

Theories of density-dependent natural selection state that at extreme population densities evolution produces alternative life histories due to trade-offs. The trade-offs are presumed to arise because those genotypes with highest fitness at high population densities will not also have high fitness at low density and vice-versa. These predictions were tested by taking samples from six populations of Drosophila melanogaster kept at low population densities (r-populations) for nearly 200 generations and placing them in crowded cultures (K-populations). After 25 generations in the crowded cultures, the derived K-populations showed growth rate and productivity that at high densities were elevated relative to the controls, but at low density were depressed.

High-density marker imputation accuracy in sixteen French cattle breeds.

PubMed

Hozé, Chris; Fouilloux, Marie-Noëlle; Venot, Eric; Guillaume, François; Dassonneville, Romain; Fritz, Sébastien; Ducrocq, Vincent; Phocas, Florence; Boichard, Didier; Croiseau, Pascal

2013-09-03

Genotyping with the medium-density Bovine SNP50 BeadChip® (50K) is now standard in cattle. The high-density BovineHD BeadChip®, which contains 777,609 single nucleotide polymorphisms (SNPs), was developed in 2010. Increasing marker density increases the level of linkage disequilibrium between quantitative trait loci (QTL) and SNPs and the accuracy of QTL localization and genomic selection. However, re-genotyping all animals with the high-density chip is not economically feasible. An alternative strategy is to genotype part of the animals with the high-density chip and to impute high-density genotypes for animals already genotyped with the 50K chip. Thus, it is necessary to investigate the error rate when imputing from the 50K to the high-density chip. Five thousand one hundred and fifty three animals from 16 breeds (89 to 788 per breed) were genotyped with the high-density chip. Imputation error rates from the 50K to the high-density chip were computed for each breed with a validation set that included the 20% youngest animals. Marker genotypes were masked for animals in the validation population in order to mimic 50K genotypes. Imputation was carried out using the Beagle 3.3.0 software. Mean allele imputation error rates ranged from 0.31% to 2.41% depending on the breed. In total, 1980 SNPs had high imputation error rates in several breeds, which is probably due to genome assembly errors, and we recommend to discard these in future studies. Differences in imputation accuracy between breeds were related to the high-density-genotyped sample size and to the genetic relationship between reference and validation populations, whereas differences in effective population size and level of linkage disequilibrium showed limited effects. Accordingly, imputation accuracy was higher in breeds with large populations and in dairy breeds than in beef breeds. More than 99% of the alleles were correctly imputed if more than 300 animals were genotyped at high-density. No improvement was observed when multi-breed imputation was performed. In all breeds, imputation accuracy was higher than 97%, which indicates that imputation to the high-density chip was accurate. Imputation accuracy depends mainly on the size of the reference population and the relationship between reference and target populations.

High-density marker imputation accuracy in sixteen French cattle breeds

PubMed Central

2013-01-01

Background Genotyping with the medium-density Bovine SNP50 BeadChip® (50K) is now standard in cattle. The high-density BovineHD BeadChip®, which contains 777 609 single nucleotide polymorphisms (SNPs), was developed in 2010. Increasing marker density increases the level of linkage disequilibrium between quantitative trait loci (QTL) and SNPs and the accuracy of QTL localization and genomic selection. However, re-genotyping all animals with the high-density chip is not economically feasible. An alternative strategy is to genotype part of the animals with the high-density chip and to impute high-density genotypes for animals already genotyped with the 50K chip. Thus, it is necessary to investigate the error rate when imputing from the 50K to the high-density chip. Methods Five thousand one hundred and fifty three animals from 16 breeds (89 to 788 per breed) were genotyped with the high-density chip. Imputation error rates from the 50K to the high-density chip were computed for each breed with a validation set that included the 20% youngest animals. Marker genotypes were masked for animals in the validation population in order to mimic 50K genotypes. Imputation was carried out using the Beagle 3.3.0 software. Results Mean allele imputation error rates ranged from 0.31% to 2.41% depending on the breed. In total, 1980 SNPs had high imputation error rates in several breeds, which is probably due to genome assembly errors, and we recommend to discard these in future studies. Differences in imputation accuracy between breeds were related to the high-density-genotyped sample size and to the genetic relationship between reference and validation populations, whereas differences in effective population size and level of linkage disequilibrium showed limited effects. Accordingly, imputation accuracy was higher in breeds with large populations and in dairy breeds than in beef breeds. More than 99% of the alleles were correctly imputed if more than 300 animals were genotyped at high-density. No improvement was observed when multi-breed imputation was performed. Conclusion In all breeds, imputation accuracy was higher than 97%, which indicates that imputation to the high-density chip was accurate. Imputation accuracy depends mainly on the size of the reference population and the relationship between reference and target populations. PMID:24004563

Complete reduction of high-density UO2 to metallic U in molten Li2O-LiCl

NASA Astrophysics Data System (ADS)

Choi, Eun-Young; Lee, Jeong

2017-10-01

The large size and high density of spent fuel pellets make it difficult to use the pellets directly in electrolytic reduction (also called as oxide reduction, OR) for pyroprocessing owing to the slow diffusion of molten Li2O-LiCl salt electrolyte into the pellets. In this study, we investigated complete OR of high-density UO2 to metallic U without any remaining UO2. Only partial reductions near the surface of high-density UO2 pellets were observed under operation conditions employing fast electrolysis rate that allowed previously complete reduction of low-density UO2 pellets. Complete reduction of high-density UO2 pellets was observed at fast electrolysis rate when the pellet size was reduced. The complete reduction of high-density UO2 pellets without size reduction was achieved at slow electrolysis rate, which allowed sufficient chemical reduction of UO2 with the lithium metal generated by the cathode reaction.

Feedback controlled, reactor relevant, high-density, high-confinement scenarios at ASDEX Upgrade

NASA Astrophysics Data System (ADS)

Lang, P. T.; Blanken, T. C.; Dunne, M.; McDermott, R. M.; Wolfrum, E.; Bobkov, V.; Felici, F.; Fischer, R.; Janky, F.; Kallenbach, A.; Kardaun, O.; Kudlacek, O.; Mertens, V.; Mlynek, A.; Ploeckl, B.; Stober, J. K.; Treutterer, W.; Zohm, H.; ASDEX Upgrade Team

2018-03-01

One main programme topic at the ASDEX Upgrade all-metal-wall tokamak is development of a high-density regime with central densities at reactor grade level while retaining high-confinement properties. This required development of appropriate control techniques capable of coping with the pellet tool, a powerful means of fuelling but one which presented challenges to the control system for handling of related perturbations. Real-time density profile control was demonstrated, raising the core density well above the Greenwald density while retaining the edge density in order to avoid confinement losses. Recently, a new model-based approach was implemented that allows direct control of the central density. Investigations focussed first on the N-seeding scenario owing to its proven potential to yield confinement enhancements. Combining pellets and N seeding was found to improve the divertor buffering further and enhance the operational range accessible. For core densities up to about the Greenwald density, a clear improvement with respect to the non-seeding reference was achieved; however, at higher densities this benefit is reduced. This behaviour is attributed to recurrence of an outward shift of the edge density profile, resulting in a reduced peeling-ballooning stability. This is similar to the shift seen during strong gas puffing, which is required to prevent impurity influx in ASDEX Upgrade. First tests indicate that highly-shaped plasma configurations like the ITER base-line scenario, respond very well to pellet injection, showing efficient fuelling with no measurable impact on the edge density profile.

Platelet density per monocyte predicts adverse events in patients after percutaneous coronary intervention.

PubMed

Rutten, Bert; Roest, Mark; McClellan, Elizabeth A; Sels, Jan W; Stubbs, Andrew; Jukema, J Wouter; Doevendans, Pieter A; Waltenberger, Johannes; van Zonneveld, Anton-Jan; Pasterkamp, Gerard; De Groot, Philip G; Hoefer, Imo E

2016-01-01

Monocyte recruitment to damaged endothelium is enhanced by platelet binding to monocytes and contributes to vascular repair. Therefore, we studied whether the number of platelets per monocyte affects the recurrence of adverse events in patients after percutaneous coronary intervention (PCI). Platelet-monocytes complexes with high and low median fluorescence intensities (MFI) of the platelet marker CD42b were isolated using cell sorting. Microscopic analysis revealed that a high platelet marker MFI on monocytes corresponded with a high platelet density per monocyte while a low platelet marker MFI corresponded with a low platelet density per monocyte (3.4 ± 0.7 vs 1.4 ± 0.1 platelets per monocyte, P=0.01). Using real-time video microscopy, we observed increased recruitment of high platelet density monocytes to endothelial cells as compared with low platelet density monocytes (P=0.01). Next, we classified PCI scheduled patients (N=263) into groups with high, medium and low platelet densities per monocyte and assessed the recurrence of adverse events. After multivariate adjustment for potential confounders, we observed a 2.5-fold reduction in the recurrence of adverse events in patients with a high platelet density per monocyte as compared with a low platelet density per monocyte [hazard ratio=0.4 (95% confidence interval, 0.2-0.8), P=0.01]. We show that a high platelet density per monocyte increases monocyte recruitment to endothelial cells and predicts a reduction in the recurrence of adverse events in patients after PCI. These findings may imply that a high platelet density per monocyte protects against recurrence of adverse events.

Evaluating Approaches to Rendering Braille Text on a High-Density Pin Display.

PubMed

Morash, Valerie S; Russomanno, Alexander; Gillespie, R Brent; OModhrain, Sile

2017-10-13

Refreshable displays for tactile graphics are typically composed of pins that have smaller diameters and spacing than standard braille dots. We investigated configurations of high-density pins to form braille text on such displays using non-refreshable stimuli produced with a 3D printer. Normal dot braille (diameter 1.5 mm) was compared to high-density dot braille (diameter 0.75 mm) wherein each normal dot was rendered by high-density simulated pins alone or in a cluster of pins configured in a diamond, X, or square; and to "blobs" that could result from covering normal braille and high-density multi-pin configurations with a thin membrane. Twelve blind participants read MNREAD sentences displayed in these conditions. For high-density simulated pins, single pins were as quickly and easily read as normal braille, but diamond, X, and square multi-pin configurations were slower and/or harder to read than normal braille. We therefore conclude that as long as center-to-center dot spacing and dot placement is maintained, the dot diameter may be open to variability for rendering braille on a high density tactile display.

Anthropogenically-Mediated Density Dependence in a Declining Farmland Bird

PubMed Central

Dunn, Jenny C.; Hamer, Keith C.; Benton, Tim G.

2015-01-01

Land management intrinsically influences the distribution of animals and can consequently alter the potential for density-dependent processes to act within populations. For declining species, high densities of breeding territories are typically considered to represent productive populations. However, as density-dependent effects of food limitation or predator pressure may occur (especially when species are dependent upon separate nesting and foraging habitats), high territory density may limit per-capita productivity. Here, we use a declining but widespread European farmland bird, the yellowhammer Emberiza citrinella L., as a model system to test whether higher territory densities result in lower fledging success, parental provisioning rates or nestling growth rates compared to lower densities. Organic landscapes held higher territory densities, but nests on organic farms fledged fewer nestlings, translating to a 5 times higher rate of population shrinkage on organic farms compared to conventional. In addition, when parental provisioning behaviour was not restricted by predation risk (i.e., at times of low corvid activity), nestling provisioning rates were higher at lower territory densities, resulting in a much greater increase in nestling mass in low density areas, suggesting that food limitation occurred at high densities. These findings in turn suggest an ecological trap, whereby preferred nesting habitat does not provide sufficient food for rearing nestlings at high population density, creating a population sink. Habitat management for farmland birds should focus not simply on creating a high nesting density, but also on ensuring heterogeneous habitats to provide food resources in close proximity to nesting birds, even if this occurs through potentially restricting overall nest density but increasing population-level breeding success. PMID:26431173

Expansion of Endothelial Progenitor Cells in High Density Dot Culture of Rat Bone Marrow Cells

PubMed Central

Wang, Ling; Kretlow, James D.; Zhou, Guangdong; Cao, Yilin; Liu, Wei; Zhang, Wen Jie

2014-01-01

In vitro expansion of endothelial progenitor cells (EPCs) remains a challenge in stem cell research and its application. We hypothesize that high density culture is able to expand EPCs from bone marrow by mimicking cell-cell interactions of the bone marrow niche. To test the hypothesis, rat bone marrow cells were either cultured in high density (2×105 cells/cm2) by seeding total 9×105 cells into six high density dots or cultured in regular density (1.6×104 cells/cm2) with the same total number of cells. Flow cytometric analyses of the cells cultured for 15 days showed that high density cells exhibited smaller cell size and higher levels of marker expression related to EPCs when compared to regular density cultured cells. Functionally, these cells exhibited strong angiogenic potentials with better tubal formation in vitro and potent rescue of mouse ischemic limbs in vivo with their integration into neo-capillary structure. Global gene chip and ELISA analyses revealed up-regulated gene expression of adhesion molecules and enhanced protein release of pro-angiogenic growth factors in high density cultured cells. In summary, high density cell culture promotes expansion of bone marrow contained EPCs that are able to enhance tissue angiogenesis via paracrine growth factors and direct differentiation into endothelial cells. PMID:25254487

High density laser-driven target

DOEpatents

Lindl, John D.

1981-01-01

A high density target for implosion by laser energy composed of a central quantity of fuel surrounded by a high-Z pusher shell with a low-Z ablator-pusher shell spaced therefrom forming a region filled with low-density material.

High density, optically corrected, micro-channel cooled, v-groove monolithic laser diode array

DOEpatents

Freitas, Barry L.

1998-01-01

An optically corrected, micro-channel cooled, high density laser diode array achieves stacking pitches to 33 bars/cm by mounting laser diodes into V-shaped grooves. This design will deliver>4kW/cm2 of directional pulsed laser power. This optically corrected, micro-channel cooled, high density laser is usable in all solid state laser systems which require efficient, directional, narrow bandwidth, high optical power density pump sources.

High performance direct methanol fuel cell with thin electrolyte membrane

NASA Astrophysics Data System (ADS)

Wan, Nianfang

2017-06-01

A high performance direct methanol fuel cell is achieved with thin electrolyte membrane. 320 mW cm-2 of peak power density and over 260 mW cm-2 at 0.4 V are obtained when working at 90 °C with normal pressure air supply. It is revealed that the increased anode half-cell performance with temperature contributes primarily to the enhanced performance at elevated temperature. From the comparison of iR-compensated cathode potential of methanol/air with that of H2/air fuel cell, the impact of methanol crossover on cathode performance decreases with current density and becomes negligible at high current density. Current density is found to influence fuel efficiency and methanol crossover significantly from the measurement of fuel efficiency at different current density. At high current density, high fuel efficiency can be achieved even at high temperature, indicating decreased methanol crossover.

High-density carbon ablator ignition path with low-density gas-filled rugby hohlraum

NASA Astrophysics Data System (ADS)

Amendt, Peter; Ho, Darwin D.; Jones, Ogden S.

2015-04-01

A recent low gas-fill density (0.6 mg/cc 4He) cylindrical hohlraum experiment on the National Ignition Facility has shown high laser-coupling efficiency (>96%), reduced phenomenological laser drive corrections, and improved high-density carbon capsule implosion symmetry [Jones et al., Bull. Am. Phys. Soc. 59(15), 66 (2014)]. In this Letter, an ignition design using a large rugby-shaped hohlraum [Amendt et al., Phys. Plasmas 21, 112703 (2014)] for high energetics efficiency and symmetry control with the same low gas-fill density (0.6 mg/cc 4He) is developed as a potentially robust platform for demonstrating thermonuclear burn. The companion high-density carbon capsule for this hohlraum design is driven by an adiabat-shaped [Betti et al., Phys. Plasmas 9, 2277 (2002)] 4-shock drive profile for robust high gain (>10) 1-D ignition performance and large margin to 2-D perturbation growth.

Synthetic high-density lipoprotein nanoconjugate targets neuroblastoma stem cells, blocking migration and self-renewal.

PubMed

Subramanian, Chitra; White, Peter T; Kuai, Rui; Kalidindi, Avinaash; Castle, Valerie P; Moon, James J; Timmermann, Barbara N; Schwendeman, Anna; Cohen, Mark S

2018-05-09

Pathways critical for neuroblastoma cancer stem cell function are targeted by 4,19,27-triacetyl withalongolide A (WGA-TA). Because neuroblastoma cells and their cancer stem cells highly overexpress the scavenger receptor class B type 1 receptor that binds to synthetic high-density lipoprotein, we hypothesized that a novel mimetic synthetic high-density lipoprotein nanoparticle would be an ideal carrier for the delivery of 4,19,27-triacetyl withalongolide to neuroblastoma and neuroblastoma cancer stem cells. Expression of scavenger receptor class B type 1 in validated human neuroblastoma cells was evaluated by quantitative polymerase chain reaction (qPCR) and Western blot. In vitro cellular uptake of synthetic high-density lipoprotein nanoparticles was observed with a fluorescence microscope. In vivo biodistribution of synthetic high-density lipoprotein nanoparticles was investigated with IVIS imaging. Self-renewal and migration/invasion were assessed by sphere formation and Boyden chamber assays, respectively. Viability was analyzed by CellTiter-Glo assay. Cancer stem cell markers were evaluated by flow cytometry. qPCR and Western blot analysis revealed a higher level of scavenger receptor class B type 1 expression and drug uptake in N-myc amplified neuroblastoma cells. In vitro uptake of synthetic high-density lipoprotein was almost completely blocked by excess synthetic high-density lipoprotein. The synthetic high-density lipoprotein nanoparticles mainly accumulated in the tumor and liver, but not in other organs. Synthetic HDL-4,19,27-triacetyl withalongolide showed a 1,000-fold higher potency than the carrier (synthetic high-density lipoprotein) alone (P < .01) to kill neuroblastoma cells. Additionally, a dose-dependent decrease in sphere formation, invasion, migration, and cancer stem cell markers was observed after treatment of neuroblastoma cells with synthetic high-density lipoprotein-4,19,27-triacetyl withalongolide A. Synthetic high-density lipoprotein is a promising platform to improve the delivery of anticancer drug 4,19,27-triacetyl withalongolide A to neuroblastomas and neuroblastoma cancer stem cells through SR-B1 targeting in vitro and in vivo. Copyright © 2018 Elsevier Inc. All rights reserved.

Lianas escape self-thinning: Experimental evidence of positive density dependence in temperate lianas Celastrus orbiculatus and C. scandens

USGS Publications Warehouse

Leicht-Young, S. A.; Latimer, A.M.; Silander, J.A.

2011-01-01

The neighborhood density of plants strongly affects their growth, reproduction, and survival. In most cases, high density increases competition and negatively affects a focal plant in predictable ways, leading to the self-thinning law. There are, however, situations in which high densities of plants facilitate focal plant performance, resulting in positive density dependence. Despite their importance in forest gap dynamics and distinctive growth form, there have been very few studies of the effect of density on lianas or vines. We grew an invasive (Celastrus orbiculatus) and a native (Celastrus scandens) liana species together in three different density treatments, while also manipulating the light and support availability. We found that across treatment conditions, C. orbiculatus always out-performed C. scandens, showing greater relative growth rate in height and diameter, greater biomass and higher survival. Both species responded similarly to the density treatments: with plants in high density not showing a decrease in relative height growth rate compared to medium density. Aboveground biomass for C. scandens was not affected by density, while for C. orbiculatus, the most massive plants were growing in medium density without support. More surprisingly, survival analysis indicated that the two species both had significantly lower mortality rates in the highest density treatment; this trend held true across the other treatments of light and supports. More generally, this study demonstrates that these lianas can escape the consequences of high density and thus the self-thinning law that affects self-supporting plants. This suggests a broader hypothesis about lianas in general: their greater flexibility in allocating growth resources allows them to grow taller and thinner without collapsing and thereby potentially escape shading and mortality even at high densities.

Sexual segregation in North American elk: the role of density dependence

PubMed Central

Stewart, Kelley M; Walsh, Danielle R; Kie, John G; Dick, Brian L; Bowyer, R Terry

2015-01-01

We investigated how density-dependent processes and subsequent variation in nutritional condition of individuals influenced both timing and duration of sexual segregation and selection of resources. During 1999–2001, we experimentally created two population densities of North American elk (Cervus elaphus), a high-density population at 20 elk/km2, and a low-density population at 4 elk/km2 to test hypotheses relative to timing and duration of sexual segregation and variation in selection of resources. We used multi-response permutation procedures to investigate patterns of sexual segregation, and resource selection functions to document differences in selection of resources by individuals in high- and low-density populations during sexual segregation and aggregation. The duration of sexual segregation was 2 months longer in the high-density population and likely was influenced by individuals in poorer nutritional condition, which corresponded with later conception and parturition, than at low density. Males and females in the high-density population overlapped in selection of resources to a greater extent than in the low-density population, probably resulting from density-dependent effects of increased intraspecific competition and lower availability of resources. PMID:25691992

High density harp for SSCL linac. [Suerconducting Super Collider Laboratory (SSCL)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fritsche, C.T.; Krogh, M.L.; Crist, C.E.

1993-05-01

AlliedSignal Inc., Kansas City Division, and the Superconducting Super Collider Laboratory (SSCL) are collaboratively developing a high density harp for the SSCL linac. This harp is designed using hybrid microcircuit (HMC) technology to obtain a higher wire density than previously available. The developed harp contains one hundred twenty-eight 33-micron-diameter carbon wires on 0.38-mm centers. The harp features an onboard broken wire detection circuit. Carbon wire preparation and attachment processes were developed. High density surface mount connectors were located. The status of high density harp development will be presented along with planned future activities.

High density harp for SSCL linac

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fritsche, C.T.; Krogh, M.L.; Crist, C.E.

1993-05-01

AlliedSignal Inc., Kansas City Division, and the Superconducting Super Collider Laboratory (SSCL) are collaboratively developing a high density harp for the SSCL linac. This harp is designed using hybrid microcircuit (HMC) technology to obtain a higher wire density than previously available. The developed harp contains one hundred twenty-eight 33-micron-diameter carbon wires on 0.38-mm centers. The harp features an onboard broken wire detection circuit. Carbon wire preparation and attachment processes were developed. High density surface mount connectors were located. The status of high density harp development will be presented along with planned future activities.

An Asymmetric Supercapacitor with Both Ultra-High Gravimetric and Volumetric Energy Density Based on 3D Ni(OH)2/MnO2@Carbon Nanotube and Activated Polyaniline-Derived Carbon.

PubMed

Shen, Juanjuan; Li, Xiaocheng; Wan, Liu; Liang, Kun; Tay, Beng Kang; Kong, Lingbin; Yan, Xingbin

2017-01-11

Development of a supercapacitor device with both high gravimetric and volumetric energy density is one of the most important requirements for their practical application in energy storage/conversion systems. Currently, improvement of the gravimetric/volumetric energy density of a supercapacitor is restricted by the insufficient utilization of positive materials at high loading density and the inferior capacitive behavior of negative electrodes. To solve these problems, we elaborately designed and prepared a 3D core-shell structured Ni(OH) 2 /MnO 2 @carbon nanotube (CNT) composite via a facile solvothermal process by using the thermal chemical vapor deposition grown-CNTs as support. Owing to the superiorities of core-shell architecture in improving the service efficiency of pseudocapacitive materials at high loading density, the prepared Ni(OH) 2 /MnO 2 @CNT electrode demonstrated a high capacitance value of 2648 F g -1 (1 A g -1 ) at a high loading density of 6.52 mg cm -2 . Coupled with high-performance activated polyaniline-derived carbon (APDC, 400 F g -1 at 1 A g -1 ), the assembled Ni(OH) 2 /MnO 2 @CNT//APDC asymmetric device delivered both high gravimetric and volumetric energy density (126.4 Wh kg -1 and 10.9 mWh cm -3 , respectively), together with superb rate performance and cycling lifetime. Moreover, we demonstrate an effective approach for building a high-performance supercapacitor with high gravimetric/volumetric energy density.

High Precision 2-D Grating Groove Density Measurement

NASA Astrophysics Data System (ADS)

Zhang, Ningxiao; McEntaffer, Randall; Tedesco, Ross

2017-08-01

Our research group at Penn State University is working on producing X-ray reflection gratings with high spectral resolving power and high diffraction efficiency. To estimate our fabrication accuracy, we apply a precise 2-D grating groove density measurement to plot groove density distributions of gratings on 6-inch wafers. In addition to plotting a fixed groove density distribution, this method is also sensitive to measuring the variation of the groove density simultaneously. This system can reach a measuring accuracy (ΔN/N) of 10-3. Here we present this groove density measurement and some applications.

Fine-scale habitat use of reintroduced black-footed ferrets on prairie dog colonies in New Mexico

USGS Publications Warehouse

Chipault, Jennifer G.; Biggins, Dean E.; Detling, James K.; Long, Dustin H.; Reich, Robin M.

2012-01-01

Black-footed ferrets (Mustela nigripes) are among the most endangered animals in North America. Reintroductions of captive-born ferrets onto prairie dog (Cynomys spp.) colonies are crucial to the conservation of the species. In September 2007, captive-born ferrets were released on a black-tailed prairie dog (Cynomys ludovicianus) colony at the Vermejo Park Ranch, New Mexico. Ferret kits experimentally released in areas of comparatively low and high prairie dog burrow densities were located via spotlight surveys. Some maturing ferret kits were subsequently translocated to areas of low and high burrow densities on nearby prairie dog colonies. For 2 months, fine-scale habitat use was quantified by mapping all burrow openings within a 30-m radius of each ferret location. Spatial statistics accounted for autocorrelation in the burrow densities in areas used by ferrets. It was hypothesized that ferrets would select areas of high burrow densities within colonies; however, burrow densities in areas used by ferrets were generally similar to the available burrow densities. Because ferrets used areas with burrow densities similar to densities available at the colony level and because of the potential energetic benefits for ferrets using areas with high burrow densities, releasing ferrets on colonies with high burrow densities might increase reintroduction success.

The low density type III ELMy H-mode regime on JET-ILW: a low density H-mode compatible with a tungsten divertor?

NASA Astrophysics Data System (ADS)

Delabie, E.; Hillesheim, J. C.; Mailloux, J.; Maggi, C. F.; Rimini, F.; Solano, E. R.; JET contributors Team

2016-10-01

The threshold power to access H-mode on JET-ILW has a minimum as function of density. Power ramps in the low and high density branch show qualitatively very different behavior above threshold. In the high density branch, edge density and temperature abruptly increase after the L-H transition, and the plasma evolves into a type I ELMy H-mode. Transitions in the low density branch are gradual and lead to the formation of a temperature pedestal, without increase in edge density. These characteristics are reminiscent of the I-mode regime, but with high frequency ELM activity. The small ELMs allow stable H-mode operation with tolerable tungsten contamination, as long as both density and power stay below the type I ELM boundary. The density range in which the low density branch can be accessed scales favourably with toroidal field but unfavourably with isotope mass. At BT=3.4T, a stable H-mode has been obtained at = 2.9 1019 m-3 with up to 15 MW of heating power at H98y 0.9. Better knowledge of the operational boundaries of this high frequency ELM regime could provide insight in how to sustain it at higher heating power for high temperature scenarios. Work supported, in part, by the US DOE under Contract No. DE-AC05-00OR22725.

Difference in distribution of membrane proteins between low- and high-density secretory granules in parotid acinar cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fujita-Yoshigaki, Junko; Katsumata, Osamu; Matsuki, Miwako

Secretory granules (SGs) are considered to be generated as immature granules and to mature by condensation of their contents. In this study, SGs of parotid gland were separated into low-, medium-, and high-density granule fractions by Percoll-density gradient centrifugation, since it was proposed that the density corresponds to the degree of maturation. The observation with electron microscopy showed that granules in the three fractions were very similar. The average diameter of high-density granules was a little but significantly larger than that of low-density granules. Although the three fractions contained amylase, suggesting that they are all SGs, distribution of membrane proteinsmore » was markedly different. Syntaxin6 and VAMP4 were localized in the low-density granule fraction, while VAMP2 was concentrated in the high-density granule fraction. Immunoprecipitation with anti-syntaxin6 antibody caused coprecipitation of VAMP2 from the medium-density granule fraction without solubilization, but not from Triton X-100-solubilized fraction, while VAMP4 was coprecipitated from both fractions. Therefore, VAMP2 is present on the same granules, but is separated from syntaxin6 and VAMP4, which are expected to be removed from immature granules. These results suggest that the medium-density granules are intermediates from low- to high-density granules, and that the membrane components of SGs dynamically change by budding and fusion during maturation.« less

β-Cobalt sulfide nanoparticles decorated graphene composite electrodes for high capacity and power supercapacitors

NASA Astrophysics Data System (ADS)

Qu, Baihua; Chen, Yuejiao; Zhang, Ming; Hu, Lingling; Lei, Danni; Lu, Bingan; Li, Qiuhong; Wang, Yanguo; Chen, Libao; Wang, Taihong

2012-11-01

Electrochemical supercapacitors have drawn much attention because of their high power and reasonably high energy densities. However, their performances still do not reach the demand of energy storage. In this paper β-cobalt sulfide nanoparticles were homogeneously distributed on a highly conductive graphene (CS-G) nanocomposite, which was confirmed by transmission electron microscopy analysis, and exhibit excellent electrochemical performances including extremely high values of specific capacitance (~1535 F g-1) at a current density of 2 A g-1, high-power density (11.98 kW kg-1) at a discharge current density of 40 A g-1 and excellent cyclic stability. The excellent electrochemical performances could be attributed to the graphene nanosheets (GNSs) which could maintain the mechanical integrity. Also the CS-G nanocomposite electrodes have high electrical conductivity. These results indicate that high electronic conductivity of graphene nanocomposite materials is crucial to achieving high power and energy density for supercapacitors.

β-Cobalt sulfide nanoparticles decorated graphene composite electrodes for high capacity and power supercapacitors.

PubMed

Qu, Baihua; Chen, Yuejiao; Zhang, Ming; Hu, Lingling; Lei, Danni; Lu, Bingan; Li, Qiuhong; Wang, Yanguo; Chen, Libao; Wang, Taihong

2012-12-21

Electrochemical supercapacitors have drawn much attention because of their high power and reasonably high energy densities. However, their performances still do not reach the demand of energy storage. In this paper β-cobalt sulfide nanoparticles were homogeneously distributed on a highly conductive graphene (CS-G) nanocomposite, which was confirmed by transmission electron microscopy analysis, and exhibit excellent electrochemical performances including extremely high values of specific capacitance (~1535 F g(-1)) at a current density of 2 A g(-1), high-power density (11.98 kW kg(-1)) at a discharge current density of 40 A g(-1) and excellent cyclic stability. The excellent electrochemical performances could be attributed to the graphene nanosheets (GNSs) which could maintain the mechanical integrity. Also the CS-G nanocomposite electrodes have high electrical conductivity. These results indicate that high electronic conductivity of graphene nanocomposite materials is crucial to achieving high power and energy density for supercapacitors.

CD3+/CD8+ T-cell density and tumoral PD-L1 predict survival irrespective of rituximab treatment in Chinese diffuse large B-cell lymphoma patients.

PubMed

Shi, Yunfei; Deng, Lijuan; Song, Yuqin; Lin, Dongmei; Lai, Yumei; Zhou, LiXin; Yang, Lei; Li, Xianghong

2018-05-10

To investigate the prognostic value of tumor-infiltrating T-cell density and programmed cell death ligand-1 (PD-L1) expression in diffuse large B cell lymphoma (DLBCL). One-hundred-twenty-five Chinese DLBCL patients were enrolled in our study and provided samples; 76 of all cases were treated with rituximab (R). Tumor tissues were immunostained and analyzed for CD3+ and CD8+ tumor-infiltrating T-cell density, tumoral PD-L1, and microenvironmental PD-L1 (mPD-L1). The density of CD3 was rated as high in 33.6% cases, while 64.0% of DLBCLs were classified as high CD8 density. Of all cases, 16.8% were PD-L1+. Of the remaining PD-L1-DLBCLs, 29.8% positively expressed mPD-L1. Both CD3 high density and CD8 high density were associated with mPD-L1 positivity (P = 0.001 and P = 0.0001). In multivariate analysis, independently, high CD3 density predicted better OS (P = 0.023), while CD8 high density and PD-L1 positivity were both associated with prolonged PFS (P = 0.013 and P = 0.036, respectively). Even in the subgroup treated with R, univariate analyses indicated that high CD3 density and PD-L1 positivity were associated with better OS (P = 0.041) and PFS (P = 0.033), respectively. The infiltrating densities of CD3+ T-cells, CD8+ T-cells, and PD-L1 expression are predictive of survival in DLBCLs, irrespective of R usage.

High density, optically corrected, micro-channel cooled, v-groove monolithic laser diode array

DOEpatents

Freitas, B.L.

1998-10-27

An optically corrected, micro-channel cooled, high density laser diode array achieves stacking pitches to 33 bars/cm by mounting laser diodes into V-shaped grooves. This design will deliver > 4kW/cm{sup 2} of directional pulsed laser power. This optically corrected, micro-channel cooled, high density laser is usable in all solid state laser systems which require efficient, directional, narrow bandwidth, high optical power density pump sources. 13 figs.

Competition between harvester ants and rodents in the cold desert

DOE Office of Scientific and Technical Information (OSTI.GOV)

Landeen, D.S.; Jorgensen, C.D.; Smith, H.D.

1979-09-30

Local distribution patterns of three rodent species (Perognathus parvus, Peromyscus maniculatus, Reithrodontomys megalotis) were studied in areas of high and low densities of harvester ants (Pogonomyrmex owyheei) in Raft River Valley, Idaho. Numbers of rodents were greatest in areas of high ant-density during May, but partially reduced in August; whereas, the trend was reversed in areas of low ant-density. Seed abundance was probably not the factor limiting changes in rodent populations, because seed densities of annual plants were always greater in areas of high ant-density. Differences in seasonal population distributions of rodents between areas of high and low ant-densities weremore » probably due to interactions of seed availability, rodent energetics, and predation.« less

Breast density estimation from high spectral and spatial resolution MRI

PubMed Central

Li, Hui; Weiss, William A.; Medved, Milica; Abe, Hiroyuki; Newstead, Gillian M.; Karczmar, Gregory S.; Giger, Maryellen L.

2016-01-01

Abstract. A three-dimensional breast density estimation method is presented for high spectral and spatial resolution (HiSS) MR imaging. Twenty-two patients were recruited (under an Institutional Review Board--approved Health Insurance Portability and Accountability Act-compliant protocol) for high-risk breast cancer screening. Each patient received standard-of-care clinical digital x-ray mammograms and MR scans, as well as HiSS scans. The algorithm for breast density estimation includes breast mask generating, breast skin removal, and breast percentage density calculation. The inter- and intra-user variabilities of the HiSS-based density estimation were determined using correlation analysis and limits of agreement. Correlation analysis was also performed between the HiSS-based density estimation and radiologists’ breast imaging-reporting and data system (BI-RADS) density ratings. A correlation coefficient of 0.91 (p<0.0001) was obtained between left and right breast density estimations. An interclass correlation coefficient of 0.99 (p<0.0001) indicated high reliability for the inter-user variability of the HiSS-based breast density estimations. A moderate correlation coefficient of 0.55 (p=0.0076) was observed between HiSS-based breast density estimations and radiologists’ BI-RADS. In summary, an objective density estimation method using HiSS spectral data from breast MRI was developed. The high reproducibility with low inter- and low intra-user variabilities shown in this preliminary study suggest that such a HiSS-based density metric may be potentially beneficial in programs requiring breast density such as in breast cancer risk assessment and monitoring effects of therapy. PMID:28042590

Biomimetic porous high-density polyethylene/polyethylene- grafted-maleic anhydride scaffold with improved in vitro cytocompatibility.

PubMed

Sharma, Swati; Bhaskar, Nitu; Bose, Surjasarathi; Basu, Bikaramjit

2018-05-01

A major challenge for tissue engineering is to design and to develop a porous biocompatible scaffold, which can mimic the properties of natural tissue. As a first step towards this endeavour, we here demonstrate a distinct methodology in biomimetically synthesized porous high-density polyethylene scaffolds. Co-extrusion approach was adopted, whereby high-density polyethylene was melt mixed with polyethylene oxide to form an immiscible binary blend. Selective dissolution of polyethylene oxide from the biphasic system revealed droplet-matrix-type morphology. An attempt to stabilize such morphology against thermal and shear effects was made by the addition of polyethylene- grafted-maleic anhydride as a compatibilizer. A maximum ultimate tensile strength of 7 MPa and elastic modulus of 370 MPa were displayed by the high-density polyethylene/polyethylene oxide binary blend with 5% maleated polyethylene during uniaxial tensile loading. The cell culture experiments with murine myoblast C2C12 cell line indicated that compared to neat high-density polyethylene and high-density polyethylene/polyethylene oxide, the high-density polyethylene/polyethylene oxide with 5% polyethylene- grafted-maleic anhydride scaffold significantly increased muscle cell attachment and proliferation with distinct elongated threadlike appearance and highly stained nuclei, in vitro. This has been partly attributed to the change in surface wettability property with a reduced contact angle (∼72°) for 5% PE- g-MA blends. These findings suggest that the high-density polyethylene/polyethylene oxide with 5% polyethylene- grafted-maleic anhydride can be treated as a cell growth substrate in bioengineering applications.

The effect of a single or repeated period of high stocking density on the behavior and response to stimuli in broiler chickens.

PubMed

Andrews, S M; Omed, H M; Phillips, C J

1997-12-01

Broiler chickens are normally housed at a fixed number per unit area throughout their life, which reduces their opportunity for movement during the later stages of rearing. An experiment is described that exposed broilers to a high stocking density either once or twice in the rearing period, and investigated the effects on the birds' behavior, and the response to other birds and humans after the second exposure to high or low stocking density. The stocking density was increased from a low level (1.7 kg/m2) to a high level (14 kg/m2) for the 2nd and/or 4th wk of rearing, or left unchanged at the low level. When stocked at the low rate, the birds spent more time walking and sitting and less time dozing and sleeping. They pecked more at inanimate objects and interacted more with other birds, but this did not include aggressive interaction. The effects of stocking density on behavior were greater in Week 4 than in Week 2, but there was no evidence that exposure to a high stocking density in Week 2 influenced the birds' behavioral response to a high stocking density in Week 4. Where stocking density did affect behavior in both Weeks 2 and 4, there was evidence of the response being cumulative. The activity of birds in the presence of another bird restrained in an open field arena was greatest when they had been stocked at the low density throughout the experiment. When a familiar person was in the arena, the birds that had been stocked at the high density in Week 2 were most active, but these birds showed the longest tonic immobility when inverted in a cradle. It is concluded that a high stocking density reduces activity in broiler chickens, and that birds stocked at a high density early in the rearing period are most active in the presence of people and show the longest tonic immobility in response to a fearful stimulus.

Associations of Breast Density With Demographic, Reproductive, and Lifestyle Factors in a Developing Southeast Asian Population.

PubMed

Dung Yun Trieu, Phuong; Mello-Thoms, Claudia; Peat, Jennifer K; Doan Do, Thuan; Brennan, Patrick C

2017-07-01

The aim of this study was to investigate how breast density interacted with demographic, reproductive, and lifestyle features among Vietnamese women. Mammographic density and established risk factors for breast cancer were collected from 1651 women (345 cancer cases and 1306 normal cases) in Vietnam. The association of breast density categories with potential risk factors was investigated using Spearman's test for continuous variables and χ 2 tests for categorical variables. Independent factors associated with high breast density and breast cancer in specific density groupings were assessed using logistic regression. Results showed that high breast density was significantly associated with young age, low body mass index, low number of children, early age at having the last child, premenopausal status, and increased vegetable consumption. Reproductive factors were key agents associated with breast cancer for women with high breast density, which was not so evident for women with low breast density.

Flying-plate detonator using a high-density high explosive

DOEpatents

Stroud, John R.; Ornellas, Donald L.

1988-01-01

A flying-plate detonator containing a high-density high explosive such as benzotrifuroxan (BTF). The detonator involves the electrical explosion of a thin metal foil which punches out a flyer from a layer overlying the foil, and the flyer striking a high-density explosive pellet of BTF, which is more thermally stable than the conventional detonator using pentaerythritol tetranitrate (PETN).

Development of a High Energy Density Capacitor for Plasma Thrusters.

DTIC Science & Technology

1980-10-01

AD-A091 839 MAXWELL LAOS INC SAN DIEGO CA FIG 81/3 DEVELOPMENT OF A HIGH ENERGY DENSITY CAPACITOR FOR PLASMA THRUS--ETC(U) OCT 80 A RAMRUS FO*611-77...of the program was the investigation of certain capacitor impregnants and their influence on high energy density capacitors which are employed in...PERIOD 1704,60~ 13 DEVELOPMENT OF A HIGH ENERGY DENSITY CAPA- Final Technical Report CITOR FOR PLASMA THRUSTERS July 1977 - May 1980 6 PERFORMING

Device and method for electron beam heating of a high density plasma

DOEpatents

Thode, L.E.

A device and method for relativistic electron beam heating of a high density plasma in a small localized region are described. A relativistic electron beam generator produces a high voltage electron beam which propagates along a vacuum drift tube and is modulated to initiate electron bunching within the beam. The beam is then directed through a low density gas chamber which provides isolation between the vacuum modulator and the relativistic electron beam target. The relativistic beam is then applied to a high density target plasma which typically comprises DT, DD, hydrogen boron or similar thermonuclear gas at a density of 10/sup 17/ to 10/sup 20/.

High-Stacking-Density, Superior-Roughness LDH Bridged with Vertically Aligned Graphene for High-Performance Asymmetric Supercapacitors.

PubMed

Guo, Wei; Yu, Chang; Li, Shaofeng; Yang, Juan; Liu, Zhibin; Zhao, Changtai; Huang, Huawei; Zhang, Mengdi; Han, Xiaotong; Niu, Yingying; Qiu, Jieshan

2017-10-01

The high-performance electrode materials with tuned surface and interface structure and functionalities are highly demanded for advanced supercapacitors. A novel strategy is presented to conFigure high-stacking-density, superior-roughness nickel manganese layered double hydroxide (LDH) bridged by vertically aligned graphene (VG) with nickel foam (NF) as the conductive collector, yielding the LDH-NF@VG hybrids for asymmetric supercapacitors. The VG nanosheets provide numerous electron transfer channels for quick redox reactions, and well-developed open structure for fast mass transport. Moreover, the high-stacking-density LDH grown and assembled on VG nanosheets result in a superior hydrophilicity derived from the tuned nano/microstructures, especially microroughness. Such a high stacking density with abundant active sites and superior wettability can be easily accessed by aqueous electrolytes. Benefitting from the above features, the LDH-NF@VG can deliver a high capacitance of 2920 F g -1 at a current density of 2 A g -1 , and the asymmetric supercapacitor with the LDH-NF@VG as positive electrode and activated carbon as negative electrode can deliver a high energy density of 56.8 Wh kg -1 at a power density of 260 W kg -1 , with a high specific capacitance retention rate of 87% even after 10 000 cycles. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Exploring organisational competences in Human Factors and UX project work: managing careers, project tactics and organisational strategy.

PubMed

Furniss, Dominic; Curzon, Paul; Blandford, Ann

2018-06-01

Organisational competence in Human Factors and UX (user experience) has not been looked at before despite its relevance to project success. We define organisational competence as the collective competence of the individuals, bringing together their complementary abilities to deliver an outcome that is typically more than the sum of its parts. Twenty-two UX and Human Factors practitioners were interviewed about their project work in two contrasting domains: web design and safety-critical systems to explore organisational competences. Through doing a FRAM analysis, 29 functions and 6 main areas of competences were identified: the central project process; the process of learning about the problem; maintaining and developing client relations; staff development; evolving practices; and the management of documentation for audit and quality control. These dynamic and situated competences form a web of interactions. Managing competences is essential for project success. Implications for managing careers, project tactics and organisational strategy are discussed. Practitioner Summary: Organisational competences impact how routine and non-routine project work is performed, but these have received little attention in the literature. Six key areas of competences in Human Factors and UX project work were identified from practitioner interviews. Managing combinations of adaptive competences is important for developing careers, project tactics and organisational strategies.

'Endurance' Goal Across the Plains

NASA Technical Reports Server (NTRS)

2004-01-01

This mosaic image from the Mars Exploration Rover Opportunity's panoramic camera provides an overview of the rover's drive direction toward 'Endurance Crater,' which is in the upper right corner of image.

The plains appear to be uniform in character from the rovers current position all the way to Endurance Crater. Granules of various sizes blanket the plains. Spherical granules fancifully called blueberries are present some intact and some broken. Larger granules pave the surface, while smaller grains, including broken blueberries, form small dunes. Randomly distributed 1-centimeter (0.4 inch) sized pebbles (as seen just left of center in the foreground of the image) make up a third type of feature on the plains. The pebbles' composition remains to be determined. Scientists plan to examine these in the coming sols.

Examination of this part of Mars by NASA's Mars Global Surveyor orbiter revealed the presence of hematite, which led NASA to choose Meridiani Planum as Opportunity's landing site. The rover science conducted on the plains of Meridiani Planum serves to integrate what the rovers are seeing on the ground with what orbital data have shown.

Opportunity will make stop at a small crater called 'Fram' (seen in the upper left, with relatively large rocks nearby) before heading to the rim of Endurance Crater.

Arctic pathways of Pacific Water: Arctic Ocean Model Intercomparison experiments.

PubMed

Aksenov, Yevgeny; Karcher, Michael; Proshutinsky, Andrey; Gerdes, Rüdiger; de Cuevas, Beverly; Golubeva, Elena; Kauker, Frank; Nguyen, An T; Platov, Gennady A; Wadley, Martin; Watanabe, Eiji; Coward, Andrew C; Nurser, A J George

2016-01-01

Pacific Water (PW) enters the Arctic Ocean through Bering Strait and brings in heat, fresh water, and nutrients from the northern Bering Sea. The circulation of PW in the central Arctic Ocean is only partially understood due to the lack of observations. In this paper, pathways of PW are investigated using simulations with six state-of-the art regional and global Ocean General Circulation Models (OGCMs). In the simulations, PW is tracked by a passive tracer, released in Bering Strait. Simulated PW spreads from the Bering Strait region in three major branches. One of them starts in the Barrow Canyon, bringing PW along the continental slope of Alaska into the Canadian Straits and then into Baffin Bay. The second begins in the vicinity of the Herald Canyon and transports PW along the continental slope of the East Siberian Sea into the Transpolar Drift, and then through Fram Strait and the Greenland Sea. The third branch begins near the Herald Shoal and the central Chukchi shelf and brings PW into the Beaufort Gyre. In the models, the wind, acting via Ekman pumping, drives the seasonal and interannual variability of PW in the Canadian Basin of the Arctic Ocean. The wind affects the simulated PW pathways by changing the vertical shear of the relative vorticity of the ocean flow in the Canada Basin.

The relationship between high residential density in student dormitories and anxiety, binge eating and Internet addiction: a study of Chinese college students.

PubMed

Tao, Zhuoli; Wu, Gao; Wang, Zeyuan

2016-01-01

Although various studies have indicated that high residential density may affect health and psychological outcomes, to our knowledge, there have been no studies regarding the predictive nature of crowded living conditions on binge eating and the use of the Internet as coping strategies. A total of 1048 Chinese college students (540 males and 508 females) were randomly selected and asked to complete a battery of questionnaires that included the Zung's Self-Rating Anxiety Scale, the Internet Addiction Test, and Rosenbaum's Self-Control Scale. Binge eating behaviors and compensatory behaviors were also reported, and variables about residential density were measured. Among female participants, binge eating scores were significantly predicted by anxiety caused by high-density living conditions (P = 0.008), and similarly, the frequency of compensatory behaviors was significantly predicted by anxiety caused by high-density living conditions (P = 0.000) and self-control (P = 0.003). Furthermore, the Internet Addiction Test scores were significantly predicted by the anxiety caused by high -density living conditions (P = 0.000) and self-control (P = 0.000). Among male participants, not only were the binge eating scores significantly predicted by the anxiety caused by high-density living conditions (P = 0.000) and self-control (P = 0.000), but the frequency of compensatory behaviors was also significantly predicted by the anxiety caused by high-density living conditions (P = 0.000) and self-control (P = 0.01). Furthermore, Internet Addiction Test scores were significantly predicted by anxiety caused by high-density living conditions (P = 0.000) and self-control (P = 0.000). It was further found that for both genders, subjective factors such as self-control, and the anxiety caused by high-density living conditions had a stronger impact on Internet addiction than objective factors, such as the size of the student's dormitory room. Moreover, self-control was found to act as a moderator in the relationship between anxiety and Internet addiction among male participants. Binge eating and Internet use could be considered coping strategies for Chinese college students facing high residential density in their dormitories.

Beyond an Equation

ERIC Educational Resources Information Center

Wilcox, Jesse; Kruse, Jerrid; Herman, Benjamin

2015-01-01

Even though density is taught in middle school, high school students often struggle to understand that the density of a substance is consistent regardless of amount. This is because many high school students know density = mass/volume, but do not have the conceptual understanding necessary to explain density-related phenomena. The scaffolded…

Flexible asymmetric supercapacitors with high energy and high power density in aqueous electrolytes

NASA Astrophysics Data System (ADS)

Cheng, Yingwen; Zhang, Hongbo; Lu, Songtao; Varanasi, Chakrapani V.; Liu, Jie

2013-01-01

Supercapacitors with both high energy and high power densities are critical for many practical applications. In this paper, we discuss the design and demonstrate the fabrication of flexible asymmetric supercapacitors based on nanocomposite electrodes of MnO2, activated carbon, carbon nanotubes and graphene. The combined unique properties of each of these components enable highly flexible and mechanically strong films that can serve as electrodes directly without using any current collectors or binders. Using these flexible electrodes and a roll-up approach, asymmetric supercapacitors with 2 V working voltage were successfully fabricated. The fabricated device showed excellent rate capability, with 78% of the original capacitance retained when the scan rate was increased from 2 mV s-1 to 500 mV s-1. Owing to the unique composite structure, these supercapacitors were able to deliver high energy density (24 W h kg-1) under high power density (7.8 kW kg-1) conditions. These features could enable supercapacitor based energy storage systems to be very attractive for a variety of critical applications, such as the power sources in hybrid electric vehicles and the back-up powers for wind and solar energy, where both high energy density and high power density are required.Supercapacitors with both high energy and high power densities are critical for many practical applications. In this paper, we discuss the design and demonstrate the fabrication of flexible asymmetric supercapacitors based on nanocomposite electrodes of MnO2, activated carbon, carbon nanotubes and graphene. The combined unique properties of each of these components enable highly flexible and mechanically strong films that can serve as electrodes directly without using any current collectors or binders. Using these flexible electrodes and a roll-up approach, asymmetric supercapacitors with 2 V working voltage were successfully fabricated. The fabricated device showed excellent rate capability, with 78% of the original capacitance retained when the scan rate was increased from 2 mV s-1 to 500 mV s-1. Owing to the unique composite structure, these supercapacitors were able to deliver high energy density (24 W h kg-1) under high power density (7.8 kW kg-1) conditions. These features could enable supercapacitor based energy storage systems to be very attractive for a variety of critical applications, such as the power sources in hybrid electric vehicles and the back-up powers for wind and solar energy, where both high energy density and high power density are required. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr33136e

Bust economics: foragers choose high quality habitats in lean times

PubMed Central

Dickman, Christopher R.

2016-01-01

In environments where food resources are spatially variable and temporarily impoverished, consumers that encounter habitat patches with different food density should focus their foraging initially where food density is highest before they move to patches where food density is lower. Increasing missed opportunity costs should drive individuals progressively to patches with lower food density as resources in the initially high food density patches deplete. To test these expectations, we assessed the foraging decisions of two species of dasyurid marsupials (dunnarts: Sminthopsis hirtipes and S. youngsoni) during a deep drought, or bust period, in the Simpson Desert of central Australia. Dunnarts were allowed access to three patches containing different food densities using an interview chamber experiment. Both species exhibited clear preference for the high density over the lower food density patches as measured in total harvested resources. Similarly, when measuring the proportion of resources harvested within the patches, we observed a marginal preference for patches with initially high densities. Models analyzing behavioral choices at the population level found no differences in behavior between the two species, but models analyzing choices at the individual level uncovered some variation. We conclude that dunnarts can distinguish between habitat patches with different densities of food and preferentially exploit the most valuable. As our observations were made during bust conditions, experiments should be repeated during boom times to assess the foraging economics of dunnarts when environmental resources are high. PMID:26839751

A promising high-energy-density material.

PubMed

Zhang, Wenquan; Zhang, Jiaheng; Deng, Mucong; Qi, Xiujuan; Nie, Fude; Zhang, Qinghua

2017-08-03

High-energy density materials represent a significant class of advanced materials and have been the focus of energetic materials community. The main challenge in this field is to design and synthesize energetic compounds with a highest possible density and a maximum possible chemical stability. Here we show an energetic compound, [2,2'-bi(1,3,4-oxadiazole)]-5,5'-dinitramide, is synthesized through a two-step reaction from commercially available reagents. It exhibits a surprisingly high density (1.99 g cm -3 at 298 K), poor solubility in water and most organic solvents, decent thermal stability, a positive heat of formation and excellent detonation properties. The solid-state structural features of the synthesized compound are also investigated via X-ray diffraction and several theoretical techniques. The energetic and sensitivity properties of the explosive compound are similar to those of 2, 4, 6, 8, 10, 12-(hexanitrohexaaza)cyclododecane (CL-20), and the developed compound shows a great promise for potential applications as a high-energy density material.High energy density materials are of interest, but density is the limiting factor for many organic compounds. Here the authors show the formation of a high density energetic compound from a two-step reaction between commercially available compounds that exhibit good heat thermal stability and detonation properties.

Evidence of low-density and high-density liquid phases and isochore end point for water confined to carbon nanotube

PubMed Central

Nomura, Kentaro; Kaneko, Toshihiro; Bai, Jaeil; Francisco, Joseph S.; Yasuoka, Kenji; Zeng, Xiao Cheng

2017-01-01

Possible transition between two phases of supercooled liquid water, namely the low- and high-density liquid water, has been only predicted to occur below 230 K from molecular dynamics (MD) simulation. However, such a phase transition cannot be detected in the laboratory because of the so-called “no-man’s land” under deeply supercooled condition, where only crystalline ices have been observed. Here, we show MD simulation evidence that, inside an isolated carbon nanotube (CNT) with a diameter of 1.25 nm, both low- and high-density liquid water states can be detected near ambient temperature and above ambient pressure. In the temperature–pressure phase diagram, the low- and high-density liquid water phases are separated by the hexagonal ice nanotube (hINT) phase, and the melting line terminates at the isochore end point near 292 K because of the retracting melting line from 292 to 278 K. Beyond the isochore end point (292 K), low- and high-density liquid becomes indistinguishable. When the pressure is increased from 10 to 600 MPa along the 280-K isotherm, we observe that water inside the 1.25-nm-diameter CNT can undergo low-density liquid to hINT to high-density liquid reentrant first-order transitions. PMID:28373562

An Electrochemical Capacitor with Applicable Energy Density of 7.4 Wh/kg at Average Power Density of 3000 W/kg.

PubMed

Zhai, Teng; Lu, Xihong; Wang, Hanyu; Wang, Gongming; Mathis, Tyler; Liu, Tianyu; Li, Cheng; Tong, Yexiang; Li, Yat

2015-05-13

Electrochemical capacitors represent a new class of charge storage devices that can simultaneously achieve high energy density and high power density. Previous reports have been primarily focused on the development of high performance capacitor electrodes. Although these electrodes have achieved excellent specific capacitance based on per unit mass of active materials, the gravimetric energy densities calculated based on the weight of entire capacitor device were fairly small. This is mainly due to the large mass ratio between current collector and active material. We aimed to address this issue by a 2-fold approach of minimizing the mass of current collector and increasing the electrode performance. Here we report an electrochemical capacitor using 3D graphene hollow structure as current collector, vanadium sulfide and manganese oxide as anode and cathode materials, respectively. 3D graphene hollow structure provides a lightweight and highly conductive scaffold for deposition of pseudocapacitive materials. The device achieves an excellent active material ratio of 24%. Significantly, it delivers a remarkable energy density of 7.4 Wh/kg (based on the weight of entire device) at the average power density of 3000 W/kg. This is the highest gravimetric energy density reported for asymmetric electrochemical capacitors at such a high power density.

Behavioural and physiological effects of population density on domesticated Zebra Finches (Taeniopygia guttata) held in aviaries.

PubMed

Poot, Hanneke; ter Maat, Andries; Trost, Lisa; Schwabl, Ingrid; Jansen, René F; Gahr, Manfred

2012-02-01

Zebra Finches (Taeniopygia guttata) are highly social and monogamous birds that display relatively low levels of aggression and coordinate group life mainly by means of vocal communication. In the wild, small groups may congregate to larger flocks of up to 150-350 birds. Little is known, however, about possible effects of population density on development in captivity. Investigating density effects on physiology and behaviour might be helpful in identifying optimal group size, in order to optimise Zebra Finch wellbeing. A direct effect of population density on development and reproduction was found: birds in lower density conditions produced significantly more and larger (body mass, tarsus length) surviving offspring than birds in high density conditions. Furthermore, offspring in low density aviaries produced slightly longer song motifs and more different syllables than their tutors, whereas offspring in high density aviaries produced shorter motifs and a smaller or similar number of different syllables than their tutors. Aggression levels within the populations were low throughout the experiment, but the number of aggressive interactions was significantly higher in high density aviaries. Baseline corticosterone levels did not differ significantly between high- and low density aviaries for either adult or offspring birds. On day 15 post hatching, brood size and baseline corticosterone levels were positively correlated. On days 60 and 100 post hatching this correlation was no longer present. The results of this study prove that population density affects various aspects of Zebra Finch development, with birds living in low population density conditions having an advantage over those living under higher population density conditions. Copyright © 2011 Elsevier Inc. All rights reserved.

Immigration Rates during Population Density Reduction in a Coral Reef Fish

PubMed Central

Turgeon, Katrine; Kramer, Donald L.

2016-01-01

Although the importance of density-dependent dispersal has been recognized in theory, few empirical studies have examined how immigration changes over a wide range of densities. In a replicated experiment using a novel approach allowing within-site comparison, we examined changes in immigration rate following the gradual removal of territorial damselfish from a limited area within a much larger patch of continuous habitat. In all sites, immigration occurred at intermediate densities but did not occur before the start of removals and only rarely as density approached zero. In the combined data and in 5 of 7 sites, the number of immigrants was a hump-shaped function of density. This is the first experimental evidence for hump-shaped, density-dependent immigration. This pattern may be more widespread than previously recognized because studies over more limited density ranges have identified positive density dependence at low densities and negative density dependence at high densities. Positive density dependence at low density can arise from limits to the number of potential immigrants and from behavioral preferences for settling near conspecifics. Negative density dependence at high density can arise from competition for resources, especially high quality territories. The potential for non-linear effects of local density on immigration needs to be recognized for robust predictions of conservation reserve function, harvest impacts, pest control, and the dynamics of fragmented populations. PMID:27271081

Integration of high capacity materials into interdigitated mesostructured electrodes for high energy and high power density primary microbatteries

NASA Astrophysics Data System (ADS)

Pikul, James H.; Liu, Jinyun; Braun, Paul V.; King, William P.

2016-05-01

Microbatteries are increasingly important for powering electronic systems, however, the volumetric energy density of microbatteries lags behind that of conventional format batteries. This paper reports a primary microbattery with energy density 45.5 μWh cm-2 μm-1 and peak power 5300 μW cm-2 μm-1, enabled by the integration of large volume fractions of high capacity anode and cathode chemistry into porous micro-architectures. The interdigitated battery electrodes consist of a lithium metal anode and a mesoporous manganese oxide cathode. The key enabler of the high energy and power density is the integration of the high capacity manganese oxide conversion chemistry into a mesostructured high power interdigitated bicontinuous cathode architecture and an electrodeposited dense lithium metal anode. The resultant energy density is greater than previously reported three-dimensional microbatteries and is comparable to commercial conventional format lithium-based batteries.

Efficient Suppression of Defects and Charge Trapping in High Density In-Sn-Zn-O Thin Film Transistor Prepared using Microwave-Assisted Sputter.

PubMed

Goh, Youngin; Ahn, Jaehan; Lee, Jeong Rak; Park, Wan Woo; Ko Park, Sang-Hee; Jeon, Sanghun

2017-10-25

Amorphous oxide semiconductor-based thin film transistors (TFTs) have been considered as excellent switching elements for driving active-matrix organic light-emitting diodes (AMOLED) owing to their high mobility and process compatibility. However, oxide semiconductors have inherent defects, causing fast transient charge trapping and device instability. For the next-generation displays such as flexible, wearable, or transparent displays, an active semiconductor layer with ultrahigh mobility and high reliability at low deposition temperature is required. Therefore, we introduced high density plasma microwave-assisted (MWA) sputtering method as a promising deposition tool for the formation of high density and high-performance oxide semiconductor films. In this paper, we present the effect of the MWA sputtering method on the defects and fast charge trapping in In-Sn-Zn-O (ITZO) TFTs using various AC device characterization methodologies including fast I-V, pulsed I-V, transient current, low frequency noise, and discharge current analysis. Using these methods, we were able to analyze the charge trapping mechanism and intrinsic electrical characteristics, and extract the subgap density of the states of oxide TFTs quantitatively. In comparison to conventional sputtered ITZO, high density plasma MWA-sputtered ITZO exhibits outstanding electrical performance, negligible charge trapping characteristics and low subgap density of states. High-density plasma MWA sputtering method has high deposition rate even at low working pressure and control the ion bombardment energy, resulting in forming low defect generation in ITZO and presenting high performance ITZO TFT. We expect the proposed high density plasma sputtering method to be applicable to a wide range of oxide semiconductor device applications.

Ground-state properties of light kaonic nuclei signaling symmetry energy at high densities

NASA Astrophysics Data System (ADS)

Yang, Rongyao; Wei, Sina; Jiang, Weizhou

2018-01-01

A sensitive correlation between the ground-state properties of light kaonic nuclei and the symmetry energy at high densities is constructed under the framework of relativistic mean-field theory. Taking oxygen isotopes as an example, we see that a high-density core is produced in kaonic oxygen nuclei, due to the strongly attractive antikaon-nucleon interaction. It is found that the 1{S}1/2 state energy in the high-density core of kaonic nuclei can directly probe the variation of the symmetry energy at supranormal nuclear density, and a sensitive correlation between the neutron skin thickness and the symmetry energy at supranormal density is established directly. Meanwhile, the sensitivity of the neutron skin thickness to the low-density slope of the symmetry energy is greatly increased in the corresponding kaonic nuclei. These sensitive relationships are established upon the fact that the isovector potential in the central region of kaonic nuclei becomes very sensitive to the variation of the symmetry energy. These findings might provide another perspective to constrain high-density symmetry energy, and await experimental verification in the future. Supported by National Natural Science Foundation of China (11775049, 11275048) and the China Jiangsu Provincial Natural Science Foundation (BK20131286)

Proteomic Markers of Functional Sperm Population in Bovines: Comparison of Low- and High-Density Spermatozoa Following Cryopreservation.

PubMed

D'Amours, Olivier; Frenette, Gilles; Bourassa, Sylvie; Calvo, Ézéchiel; Blondin, Patrick; Sullivan, Robert

2018-01-05

Mammalian semen contains a heterogeneous population of sperm cells. This heterogeneity results from variability in the complex processes of cell differentiation in the testis, biochemical modifications undergone by spermatozoa during transit along the male reproductive tract, interactions with secretions from accessory sex glands at ejaculation, and, in the context of reproductive technologies, in the ability of ejaculated spermatozoa to resist damage associated with freeze-thaw procedures. When submitted to density gradient centrifugation, ejaculated spermatozoa distribute themselves into two distinct populations: a low-density population characterized by low motility parameters, and a high-density population with high motility characteristics. To understand the origin of ejaculated spermatozoa heterogeneity, cryopreserved semen samples from bulls used by the artificial insemination (A.I.) industry were submitted to Percoll gradient centrifugation. Proteins from low and high density spermatozoa were then extracted with sodium deoxycholate and submitted to proteomic analysis using iTRAQ (isobaric tag for relative and absolute quantitation) methodologies. Quantification of selected sperm proteins was confirmed by multiple reaction monitoring (MRM). Overall, 31 different proteins were more abundant in low-density spermatozoa, while 80 different proteins were more abundant in the high-density subpopulation. Proteins enriched in high-density spermatozoa were markers of sperm functionality such as the glycolytic process, binding to the egg zona pellucida, and motility. Low-density spermatozoa were not solely characterized by loss of proteins and their associated functions. Chaperonin-containing TCP1s and chaperones are hallmarks of the low-density subpopulation. iTRAQ analysis revealed that other proteins such as binder of sperm proteins, histone, GPX5, ELSPBP1, and clusterin are overexpressed in low-density spermatozoa suggesting that these proteins represent defects occurring at different steps during the sperm journey. These differences contribute to the sperm cell heterogeneity present in mammalian semen.

High-Capacity Cathode Material with High Voltage for Li-Ion Batteries

DOE PAGES

Shi, Ji -Lei; Xiao, Dong -Dong; Ge, Mingyuan; ...

2018-01-15

Electrochemical energy storage devices with a high energy density are an important technology in modern society, especially for electric vehicles. The most effective approach to improve the energy density of batteries is to search for high-capacity electrode materials. According to the concept of energy quality, a high-voltage battery delivers a highly useful energy, thus providing a new insight to improve energy density. Based on this concept, a novel and successful strategy to increase the energy density and energy quality by increasing the discharge voltage of cathode materials and preserving high capacity is proposed. The proposal is realized in high-capacity Li-richmore » cathode materials. The average discharge voltage is increased from 3.5 to 3.8 V by increasing the nickel content and applying a simple after-treatment, and the specific energy is improved from 912 to 1033 Wh kg-1. The current work provides an insightful universal principle for developing, designing, and screening electrode materials for high energy density and energy quality.« less

High-Capacity Cathode Material with High Voltage for Li-Ion Batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shi, Ji -Lei; Xiao, Dong -Dong; Ge, Mingyuan

Electrochemical energy storage devices with a high energy density are an important technology in modern society, especially for electric vehicles. The most effective approach to improve the energy density of batteries is to search for high-capacity electrode materials. According to the concept of energy quality, a high-voltage battery delivers a highly useful energy, thus providing a new insight to improve energy density. Based on this concept, a novel and successful strategy to increase the energy density and energy quality by increasing the discharge voltage of cathode materials and preserving high capacity is proposed. The proposal is realized in high-capacity Li-richmore » cathode materials. The average discharge voltage is increased from 3.5 to 3.8 V by increasing the nickel content and applying a simple after-treatment, and the specific energy is improved from 912 to 1033 Wh kg-1. The current work provides an insightful universal principle for developing, designing, and screening electrode materials for high energy density and energy quality.« less

Future Road Density

EPA Pesticide Factsheets

Road density is generally highly correlated with amount of developed land cover. High road densities usually indicate high levels of ecological disturbance. More information about these resources, including the variables used in this study, may be found here: https://edg.epa.gov/data/Public/ORD/NERL/ReVA/ReVA_Data.zip.

Road density

EPA Pesticide Factsheets

Road density is generally highly correlated with amount of developed land cover. High road densities usually indicate high levels of ecological disturbance. More information about these resources, including the variables used in this study, may be found here: https://edg.epa.gov/data/Public/ORD/NERL/ReVA/ReVA_Data.zip.

The Effects of Density in a High-Rise Residence Hall on Helping Behavior and Social Interaction

ERIC Educational Resources Information Center

Stoner, Kenneth L.; Thurman, Christopher W.

1978-01-01

Focuses on the effects of high-density housing on the helping behaviors and social interactions of the residents living within such buildings. Concludes by recommending ways to overcome some of the negative effects of high-density housing. (Author)

High bandwidth vapor density diagnostic system

DOEpatents

Globig, Michael A.; Story, Thomas W.

1992-01-01

A high bandwidth vapor density diagnostic system for measuring the density of an atomic vapor during one or more photoionization events. The system translates the measurements from a low frequency region to a high frequency, relatively noise-free region in the spectrum to provide improved signal to noise ratio.

Screen-detected versus interval cancers: Effect of imaging modality and breast density in the Flemish Breast Cancer Screening Programme.

PubMed

Timmermans, Lore; Bleyen, Luc; Bacher, Klaus; Van Herck, Koen; Lemmens, Kim; Van Ongeval, Chantal; Van Steen, Andre; Martens, Patrick; De Brabander, Isabel; Goossens, Mathieu; Thierens, Hubert

2017-09-01

To investigate if direct radiography (DR) performs better than screen-film mammography (SF) and computed radiography (CR) in dense breasts in a decentralized organised Breast Cancer Screening Programme. To this end, screen-detected versus interval cancers were studied in different BI-RADS density classes for these imaging modalities. The study cohort consisted of 351,532 women who participated in the Flemish Breast Cancer Screening Programme in 2009 and 2010. Information on screen-detected and interval cancers, breast density scores of radiologist second readers, and imaging modality was obtained by linkage of the databases of the Centre of Cancer Detection and the Belgian Cancer Registry. Overall, 67% of occurring breast cancers are screen detected and 33% are interval cancers, with DR performing better than SF and CR. The interval cancer rate increases gradually with breast density, regardless of modality. In the high-density class, the interval cancer rate exceeds the cancer detection rate for SF and CR, but not for DR. DR is superior to SF and CR with respect to cancer detection rates for high-density breasts. To reduce the high interval cancer rate in dense breasts, use of an additional imaging technique in screening can be taken into consideration. • Interval cancer rate increases gradually with breast density, regardless of modality. • Cancer detection rate in high-density breasts is superior in DR. • IC rate exceeds CDR for SF and CR in high-density breasts. • DR performs better in high-density breasts for third readings and false-positives.

Device and method for electron beam heating of a high density plasma

DOEpatents

Thode, Lester E.

1981-01-01

A device and method for relativistic electron beam heating of a high density plasma in a small localized region. A relativistic electron beam generator produces a high voltage electron beam which propagates along a vacuum drift tube and is modulated to initiate electron bunching within the beam. The beam is then directed through a low density gas chamber which provides isolation between the vacuum modulator and the relativistic electron beam target. The relativistic beam is then applied to a high density target plasma which typically comprises DT, DD, hydrogen boron or similar thermonuclear gas at a density of 10.sup.17 to 10.sup.20 electrons per cubic centimeter. The target plasma is ionized prior to application of the electron beam by means of a laser or other preionization source. Utilizing a relativistic electron beam with an individual particle energy exceeding 3 MeV, classical scattering by relativistic electrons passing through isolation foils is negligible. As a result, relativistic streaming instabilities are initiated within the high density target plasma causing the relativistic electron beam to efficiently deposit its energy into a small localized region within the high density plasma target.

Identification of the trypanocidal factor in normal human serum: high density lipoprotein.

PubMed Central

Rifkin, M R

1978-01-01

The differentiation of Trypanosoma brucei from T. rhodesiense, the causative agent of human sleeping sickness, depends on their relative sensitivities to the cytotoxic effects of normal human serum. The molecule responsible for the specific lysis of T. brucei has now been isolated. Serum lipoproteins were fractionated and purified by ultracentrifugal flotation and chromatography on Bio-Gel A-5m. Trypanocidal activity was recovered in the high density lipoprotein fraction (density, 1.063-1.216 g/ml). Contamination by other serum proteins was checked by crossed immunoelectrophoresis and sodium dodecyl sulfate/acrylamide gel electrophoresis. Only a trace of beta-lipoprotein was found. The trypanocidal activity of pure human high density lipoprotein was identical to that of unfractionated serum when the following were tested: (i) time course of in vitro lysis of T. bruceli; (ii) in vivo destruction of T. brucei; (iii) relative resistance of T. rhodesiense to lysis. Rat or rabbit high density lipoprotein had no trypanocidal activity. Identification of the trypanocidal factor as high density lipoprotein was confirmed by the finding that serum from patients with Tangier disease, an autosomal recessive disorder characterized by a severe deficiency of high density lipoprotein, had no trypanocidal activity. Images PMID:210461

Does the prediction of breast cancer improve using a combination of mammographic density measures compared to individual measures alone?

NASA Astrophysics Data System (ADS)

Wong Sik Hee, Joseph Ryan; Harkness, Elaine F.; Gadde, Soujanya; Lim, Yit Y.; Maxwell, Anthony J.; Evans, D. Gareth; Howell, Anthony; Astley, Susan M.

2017-03-01

High mammographic density is associated with an increased risk of breast cancer, however whether the association is stronger when there is agreement across measures is unclear. This study investigates whether a combination of density measures is a better predictor of breast cancer risk than individual methods alone. Women recruited to the Predicting Risk of Cancer At Screening (PROCAS) study and with mammographic density assessed using three different methods were included (n=33,304). Density was assessed visually using Visual Analogue Scales (VAS) and by two fully automated methods, Quantra and Volpara. Percentage breast density was divided into (high, medium and low) and combinations of measures were used to further categorise individuals (e.g. `all high'). A total of 667 breast cancers were identified and logistic regression was used to determine the relationship between breast density and breast cancer risk. In total, 44% of individuals were in the same tertile for all three measures, 8.6% were in non-adjacent (high and low) or mixed categories (high, medium and low). For individual methods the strongest association with breast cancer risk was for medium and high tertiles of VAS with odds ratios (OR) adjusted for age and BMI of 1.63 (95% CI 1.31-2.03) and 2.33 (1.87-2.90) respectively. For the combination of density methods the strongest association was for `all high' (OR 2.42, 1.77-3.31) followed by "two high" (OR 1.90, 1.35-3.31) and "two medium" (OR 1.88, 1.40-2.52). Combining density measures did not affect the magnitude of risk compared to using individual methods.

Electron density profile measurements at a self-focusing ion beam with high current density and low energy extracted through concave electrodes.

PubMed

Fujiwara, Y; Hirano, Y; Kiyama, S; Nakamiya, A; Koguchi, H; Sakakita, H

2014-02-01

The self-focusing phenomenon has been observed in a high current density and low energy ion beam. In order to study the mechanism of this phenomenon, a special designed double probe to measure the electron density and temperature is installed into the chamber where the high current density ion beam is injected. Electron density profile is successfully measured without the influence of the ion beam components. Estimated electron temperature and density are ∼0.9 eV and ∼8 × 10(8) cm(-3) at the center of ion beam cross section, respectively. It was found that a large amount of electrons are spontaneously accumulated in the ion beam line in the case of self-forcing state.

HIGH STAR FORMATION RATES IN TURBULENT ATOMIC-DOMINATED GAS IN THE INTERACTING GALAXIES IC 2163 AND NGC 2207

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elmegreen, Bruce G.; Kaufman, Michele; Bournaud, Frédéric

CO observations of the interacting galaxies IC 2163 and NGC 2207 are combined with HI, H α , and 24 μ m observations to study the star formation rate (SFR) surface density as a function of the gas surface density. More than half of the high-SFR regions are HI dominated. When compared to other galaxies, these HI-dominated regions have excess SFRs relative to their molecular gas surface densities but normal SFRs relative to their total gas surface densities. The HI-dominated regions are mostly located in the outer part of NGC 2207 where the HI velocity dispersion is high, 40–50 kmmore » s{sup −1}. We suggest that the star-forming clouds in these regions have envelopes at lower densities than normal, making them predominantly atomic, and cores at higher densities than normal because of the high turbulent Mach numbers. This is consistent with theoretical predictions of a flattening in the density probability distribution function for compressive, high Mach number turbulence.« less

Three-Dimensional Expanded Graphene-Metal Oxide Film via Solid-State Microwave Irradiation for Aqueous Asymmetric Supercapacitors.

PubMed

Yang, MinHo; Lee, Kyoung G; Lee, Seok Jae; Lee, Sang Bok; Han, Young-Kyu; Choi, Bong Gill

2015-10-14

Carbon-based electrochemical double-layer capacitors and pseudocapacitors, consisting of a symmetric configuration of electrodes, can deliver much higher power densities than batteries, but they suffer from low energy densities. Herein, we report the development of high energy and power density supercapacitors using an asymmetric configuration of Fe2O3 and MnO2 nanoparticles incorporated into 3D macroporous graphene film electrodes that can be operated in a safe and low-cost aqueous electrolyte. The gap in working potential windows of Fe2O3 and MnO2 enables the stable expansion of the cell voltage up to 1.8 V, which is responsible for the high energy density (41.7 Wh kg(-1)). We employ a household microwave oven to simultaneously create conductivity, porosity, and the deposition of metal oxides on graphene films toward 3D hybrid architectures, which lead to a high power density (13.5 kW kg(-1)). Such high energy and power densities are maintained for over 5000 cycles, even during cycling at a high current density of 16.9 A g(-1).

14 CFR 93.129 - Additional operations.

Code of Federal Regulations, 2010 CFR

2010-01-01

...) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES High Density Traffic Airports § 93... under IFR at a designated high density traffic airport without regard to the maximum number of operations allocated for that airport if the operation is not a scheduled operation to or from a high density...

75 FR 72858 - Agency Information Collection Activities: Requests for Comments; Clearance of Renewed Approval of...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-26

... Activities: Requests for Comments; Clearance of Renewed Approval of Information Collection: High Density... records of slot transfers at High Density Traffic Airports. The information is provided by air carriers and commuter operators, or other persons holding a slot at High Density Airports. DATES: Written...

75 FR 52802 - Agency Information Collection Activities: Requests for Comments; Clearance of Renewed Approval of...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-27

... Activities: Requests for Comments; Clearance of Renewed Approval of Information Collection: High Density... maintain accurate records of slot transfers at High Density Traffic Airports. The information is provided by air carriers and commuter operators, or other persons holding a slot at High Density Airports...

14 CFR 93.129 - Additional operations.

Code of Federal Regulations, 2014 CFR

2014-01-01

...) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES High Density Traffic Airports § 93... under IFR at a designated high density traffic airport without regard to the maximum number of operations allocated for that airport if the operation is not a scheduled operation to or from a high density...

14 CFR 93.129 - Additional operations.

Code of Federal Regulations, 2013 CFR

2013-01-01

...) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES High Density Traffic Airports § 93... under IFR at a designated high density traffic airport without regard to the maximum number of operations allocated for that airport if the operation is not a scheduled operation to or from a high density...

14 CFR 93.129 - Additional operations.

Code of Federal Regulations, 2011 CFR

2011-01-01

...) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES High Density Traffic Airports § 93... under IFR at a designated high density traffic airport without regard to the maximum number of operations allocated for that airport if the operation is not a scheduled operation to or from a high density...

14 CFR 93.129 - Additional operations.

Code of Federal Regulations, 2012 CFR

2012-01-01

...) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES High Density Traffic Airports § 93... under IFR at a designated high density traffic airport without regard to the maximum number of operations allocated for that airport if the operation is not a scheduled operation to or from a high density...

Reactor coolant pump flywheel

DOEpatents

Finegan, John Raymond; Kreke, Francis Joseph; Casamassa, John Joseph

2013-11-26

A flywheel for a pump, and in particular a flywheel having a number of high density segments for use in a nuclear reactor coolant pump. The flywheel includes an inner member and an outer member. A number of high density segments are provided between the inner and outer members. The high density segments may be formed from a tungsten based alloy. A preselected gap is provided between each of the number of high density segments. The gap accommodates thermal expansion of each of the number of segments and resists the hoop stress effect/keystoning of the segments.

High-density QCD phase transitions inside neutron stars: Glitches and gravitational waves

NASA Astrophysics Data System (ADS)

Srivastava, A. M.; Bagchi, P.; Das, A.; Layek, B.

2017-10-01

We discuss physics of exotic high baryon density QCD phases which are believed to exist in the core of a neutron star. This can provide a laboratory for exploring exotic physics such as axion emission, KK graviton production etc. Much of the physics of these high-density phases is model-dependent and not very well understood, especially the densities expected to occur inside neutron stars. We follow a different approach and use primarily universal aspects of the physics of different high-density phases and associated phase transitions. We study effects of density fluctuations during transitions with and without topological defect production and study the effect on pulsar timings due to changing moment of inertia of the star. We also discuss gravitational wave production due to rapidly changing quadrupole moment of the star due to these fluctuations.

High-density carbon nanotube buckypapers with superior transport and mechanical properties.

PubMed

Zhang, Ling; Zhang, Guang; Liu, Changhong; Fan, Shoushan

2012-09-12

High-density buckypapers were obtained by using well-aligned carbon nanotube arrays. The density of the buckypapers was as high as 1.39 g cm(-3), which is close to the ultimate density of ideal buckypapers. Then we measured the transport and mechanical properties of the buckypapers. Our results demonstrated that its electrical and thermal conductivities could be almost linearly improved by increasing its density. In particular, its superior thermal conductivity is nearly twice that of common metals, which enables it a lightweight and more efficient heat-transfer materials. The Young's modulus of the buckypapers could reach a magnitude over 2 GPa, which is greatly improved compared with previous reported results. In view of this, our work provided a simple and convenient method to prepare high-density buckypapers with excellent transport and mechanical properties.

The Three-part Structure of a Filament-unrelated Solar Coronal Mass Ejection

NASA Astrophysics Data System (ADS)

Song, H. Q.; Cheng, X.; Chen, Y.; Zhang, J.; Wang, B.; Li, L. P.; Li, B.; Hu, Q.; Li, G.

2017-10-01

Coronal mass ejections (CMEs) often exhibit the typical three-part structure in the corona when observed with white-light coronagraphs, I.e., the bright leading front, dark cavity, and bright core, corresponding to a high-low-high density sequence. As CMEs result from eruptions of magnetic flux ropes (MFRs), which can possess either lower (e.g., coronal-cavity MFRs) or higher (e.g., hot-channel MFRs) density compared to their surroundings in the corona, the traditional opinion regards the three-part structure as the manifestations of coronal plasma pileup (high density), coronal-cavity MFR (low density), and filament (high density) contained in the trailing part of MFR, respectively. In this paper, we demonstrate that filament-unrelated CMEs can also exhibit the classical three-part structure. The observations were made from different perspectives through an event that occurred on 2011 October 4. The CME cavity corresponds to the low-density zone between the leading front and the high-density core, and it is obvious in the low corona and gradually becomes fuzzy when propagating outward. The bright core corresponds to a high-density structure that is suggested to be an erupting MFR. The MFR is recorded from both edge-on and face-on perspectives, exhibiting different morphologies that are due to projection effects. We stress that the zone (MFR) with lower (higher) density in comparison to the surroundings can appear as the dark cavity (bright core) when observed through white-light coronagraphs, which is not necessarily the coronal-cavity MFR (erupted filament).

Influence of stocking density on growth, body composition and energy budget of Atlantic salmon Salmo salar L. in recirculating aquaculture systems

NASA Astrophysics Data System (ADS)

Liu, Baoliang; Liu, Ying; Liu, Ziyi; Qiu, Denggao; Sun, Guoxiang; Li, Xian

2014-09-01

Atlantic salmon Salmo salar were reared at four stocking densities—high density D 1 (final density ˜39 kg/m3), medium densities D 2 (˜29 kg/m3) and D 3 (˜19 kg/m3), and low density D 4 (˜12 kg/m3)—for 40 days to investigate the effect of stocking density on their growth performance, body composition and energy budgets. Stocking density did not significantly affect specific growth rate in terms of weight (SGRw) but did affect specific growth rate in terms of energy (SGRe). Stocking density significantly influenced the ration level (RLw and RLe), feed conversion ratio (FCRw and FCRe) and apparent digestibility rate (ADR). Ration level and FCRw tended to increase with increasing density. Fish at the highest density D 1 and lowest density D 4 showed lower FCRe and higher ADR than at medium densities. Stocking density significantly affected protein and energy contents of the body but did not affect its moisture, lipid, or ash contents. The expenditure of energy for metabolism in the low-density and high-density groups was lower than that in the medium-density groups. Stocking density affected energy utilization from the feces but had no effect on excretion rate. The greater energy allocation to growth at high density and low density may be attributed to reduced metabolic rate and increased apparent digestibility rate. These findings provide information that will assist selection of suitable stocking densities in the Atlantic-salmon-farming industry.

Triglycerides, total cholesterol, high density lipoprotein cholesterol and low density lipoprotein cholesterol in rats exposed to premium motor spirit fumes.

PubMed

Aberare, Ogbevire L; Okuonghae, Patrick; Mukoro, Nathaniel; Dirisu, John O; Osazuwa, Favour; Odigie, Elvis; Omoregie, Richard

2011-06-01

Deliberate and regular exposure to premium motor spirit fumes is common and could be a risk factor for liver disease in those who are occupationally exposed. A possible association between premium motor spirit fumes and plasma levels of triglyceride, total cholesterol, high density lipoprotein cholesterol and low density lipoprotein cholesterol using a rodent model could provide new insights in the pathology of diseases where cellular dysfunction is an established risk factor. The aim of this study was to evaluate the possible effect of premium motor spirit fumes on lipids and lipoproteins in workers occupationally exposed to premium motor spirit fumes using rodent model. Twenty-five Wister albino rats (of both sexes) were used for this study between the 4(th) of August and 7(th) of September, 2010. The rats were divided into five groups of five rats each. Group 1 rats were not exposed to premium motor spirit fumes (control group), group 2 rats were exposed for 1 hour daily, group 3 for 3 hours daily, group 4 for 5 hours daily and group 5 for 7 hours daily. The experiment lasted for a period of 4 weeks. Blood samples obtained from all the groups after 4 weeks of exposure were used for the estimation of plasma levels of triglyceride, total cholesterol, high density lipoprotein- cholesterol and low density lipoprotein- cholesterol. Results showed significant increase in means of plasma total cholesterol and low density lipoprotein levels (P<0.05). The mean triglyceride and total body weight were significantly lower (P<0.05) in the exposed group when compared with the unexposed. The plasma level of high density lipoprotein, the ratio of low density lipoprotein to high density lipoprotein and the ratio of total cholesterol to high density lipoprotein did not differ significantly in exposed subjects when compared with the control group. These results showed that frequent exposure to petrol fumes may be highly deleterious to the liver cells.

A high plant density reduces the ability of maize to use soil nitrogen

PubMed Central

Yan, Peng; Pan, Junxiao; Zhang, Wenjie; Shi, Junfang; Chen, Xinping; Cui, Zhenling

2017-01-01

Understanding the physiological changes associated with high grain yield and high N use efficiency (NUE) is important when increasing the plant density and N rate to develop optimal agronomic management. We tested the hypothesis that high plant densities resulting in crowding stress reduce the ability of plants to use the N supply post-silking, thus decreasing the grain yield and NUE. In 2013 and 2014, a field experiment, with five N-application rates and three plant densities (6.0, 7.5, and 9.0 plants m–2), was conducted in the North China Plain (NCP). The calculated maximum grain yield and agronomic use efficiency (AEN) at a density of 7.5 plants m–2 were 12.4 Mg ha–1 and 39.3 kg kg–1, respectively, which were significantly higher than the values obtained at densities of 6.0 (11.3 Mg ha–1 and 30.2 kg kg–1) and 9.0 plant m–2 (11.7 Mg ha–1 and 27.8 kg kg–1). A high plant density of 9.0 plants m–2 decreased the post-silking N accumulation, leaf N concentration and net photosynthesis, which reduced the post-silking dry matter production, resulting in a low yield and NUE. Although a relatively low grain yield was observed at a density of 9.0 plants m–2, the optimal N rate increased from 150 to 186 kg N ha-1 at a density of 7.5 plants m–2. These results indicate that high plant densities with crowding stress reduce the ability of plants to use soil N during the post-silking period, and high rate of N fertilizer was needed to increase grain yield. We conclude that selecting the appropriate plant density combined with optimal N management could increase grain yields and the NUE in the NCP. PMID:28234970

Mercury Slovenian soils: High, medium and low sample density geochemical maps

NASA Astrophysics Data System (ADS)

Gosar, Mateja; Šajn, Robert; Teršič, Tamara

2017-04-01

Regional geochemical survey was conducted in whole territory of Slovenia (20273 km2). High, medium and low sample density surveys were compared. High sample density represented the regional geochemical data set supplemented by local high-density sampling data (irregular grid, n=2835). Medium-density soil sampling was performed in a 5 x 5 km grid (n=817) and low-density geochemical survey was conducted in a sampling grid 25 x 25 km (n=54). Mercury distribution in Slovenian soils was determined with models of mercury distribution in soil using all three data sets. A distinct Hg anomaly in western part of Slovenia is evident on all three models. It is a consequence of 500-years of mining and ore processing in the second largest mercury mine in the world, the Idrija mine. The determined mercury concentrations revealed an important difference between the western and the eastern parts of the country. For the medium scale geochemical mapping is the median value (0.151 mg /kg) for western Slovenia almost 2-fold higher than the median value (0.083 mg/kg) in eastern Slovenia. Besides the Hg median for the western part of Slovenia exceeds the Hg median for European soil by a factor of 4 (Gosar et al., 2016). Comparing these sample density surveys, it was shown that high sampling density allows the identification and characterization of anthropogenic influences on a local scale, while medium- and low-density sampling reveal general trends in the mercury spatial distribution, but are not appropriate for identifying local contamination in industrial regions and urban areas. The resolution of the pattern generated is the best when the high-density survey on a regional scale is supplemented with the geochemical data of the high-density surveys on a local scale. References: Gosar, M, Šajn, R, Teršič, T. Distribution pattern of mercury in the Slovenian soil: geochemical mapping based on multiple geochemical datasets. Journal of geochemical exploration, 2016, 167/38-48.

Relationship between Depressive Symptoms and Cardiovascular Disease Risk Factors in African American Individuals

DTIC Science & Technology

2011-01-01

cholesterol , triglycerides , high - density cholesterol (HDL), and calculated low- density lipoprotein (LDL)), and blood glucose level. 2.3. Assessments 2.3.1...separately; BP: blood pressure; HDL: high - density lipoprotein ; LDL: low- density lipoprotein . at or above threshold with those who do not among a group of...261, 2001. [11] G. R. Warnick, R. H. Knopp, V. Fitzpatrick, and L. Branson, “Estimating low- density lipoprotein

Aggressive and foraging behavioral interactions among ruffe

USGS Publications Warehouse

Savino, Jacqueline F.; Kostich, Melissa J.

2000-01-01

The ruffe, Gymnocephalus cernuus, is a nonindigenous percid in the Great Lakes. Ruffe are aggressive benthivores and forage over soft substrates. Laboratory studies in pools (100 cm in diameter, 15 cm water depth) were conducted to determine whether fish density (low = 2, medium = 4, high = 6 ruffe per pool) changed foraging and aggressive behaviors with a limited food supply of chironomid larvae. All fish densities demonstrated a hierarchy based on aggressive interactions, but ruffe were most aggressive at low and high fish densities. Time spent in foraging was lowest at the low fish density. The best forager at the low fish density was the most aggressive individual, but the second most aggressive fish at the medium and high fish density was the best forager and also the one chased most frequently. A medium fish density offered the best energetic benefits to ruffe by providing the lowest ratio of time spent in aggression to that spent foraging. Based on our results, ruffe should grow best at an intermediate density. With high ruffe densities, we would also expect disparity in size as the more aggressive fish are able to garner a disproportionate amount of the resources. Alternatively, as the Great Lakes are a fairly open system, ruffe could migrate out of one area to colonize another as populations exceed optimal densities.

High Discharge Energy Density at Low Electric Field Using an Aligned Titanium Dioxide/Lead Zirconate Titanate Nanowire Array.

PubMed

Zhang, Dou; Liu, Weiwei; Guo, Ru; Zhou, Kechao; Luo, Hang

2018-02-01

Polymer-based capacitors with high energy density have attracted significant attention in recent years due to their wide range of potential applications in electronic devices. However, the obtained high energy density is predominantly dependent on high applied electric field, e.g., 400-600 kV mm -1 , which may bring more challenges relating to the failure probability. Here, a simple two-step method for synthesizing titanium dioxide/lead zirconate titanate nanowire arrays is exploited and a demonstration of their ability to achieve high discharge energy density capacitors for low operating voltage applications is provided. A high discharge energy density of 6.9 J cm -3 is achieved at low electric fields, i.e., 143 kV mm -1 , which is attributed to the high relative permittivity of 218.9 at 1 kHz and high polarization of 23.35 µC cm -2 at this electric field. The discharge energy density obtained in this work is the highest known for a ceramic/polymer nanocomposite at such a low electric field. The novel nanowire arrays used in this work are applicable to a wide range of fields, such as energy harvesting, energy storage, and photocatalysis.

Population density predicts outcome from out-of-hospital cardiac arrest in Victoria, Australia.

PubMed

Nehme, Ziad; Andrew, Emily; Cameron, Peter A; Bray, Janet E; Bernard, Stephen A; Meredith, Ian T; Smith, Karen

2014-05-05

To examine the impact of population density on incidence and outcome of out-of-hospital cardiac arrest (OHCA). Data were extracted from the Victorian Ambulance Cardiac Arrest Registry for all adult OHCA cases of presumed cardiac aetiology attended by the emergency medical service (EMS) between 1 January 2003 and 31 December 2011. Cases were allocated into one of five population density groups according to their statistical local area: very low density (≤ 10 people/km(2)), low density (11-200 people/km(2)), medium density (201-1000 people/km(2)), high density (1001-3000 people/km(2)), and very high density (> 3000 people/km(2)). Survival to hospital and survival to hospital discharge. The EMS attended 27 705 adult presumed cardiac OHCA cases across 204 Victorian regions. In 12 007 of these (43.3%), resuscitation was attempted by the EMS. Incidence was lower and arrest characteristics were consistently less favourable for lower population density groups. Survival outcomes, including return of spontaneous circulation, survival to hospital and survival to hospital discharge, were significantly poorer in less densely populated groups (P < 0.001 for all comparisons). When compared with very low density populations, the risk-adjusted odds ratios of surviving to hospital discharge were: low density, 1.88 (95% CI, 1.15-3.07); medium density, 2.49 (95% CI, 1.55-4.02); high density, 3.47 (95% CI, 2.20-5.48) and very high density, 4.32 (95% CI, 2.67-6.99). Population density is independently associated with survival after OHCA, and significant variation in the incidence and characteristics of these events are observed across the state.

Investigation of physical processes limiting plasma density in H-mode on DIII-D

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maingi, R.; Mahdavi, M.A.; Jernigan, T.C.

1996-12-01

A series of experiments was conducted on the DIII-D tokamak to investigate the physical processes which limit density in high confinement mode (H-mode) discharges. The typical H-mode to low confinement mode (L-mode) transition limit at high density near the empirical Greenwald density limit was avoided by divertor pumping, which reduced divertor neutral pressure and prevented formation of a high density, intense radiation zone (MARFE) near the X-point. It was determined that the density decay time after pellet injection was independent of density relative to the Greenwald limit and increased non-linearly with the plasma current. Magnetohydrodynamic (MHD) activity in pellet-fueled plasmasmore » was observed at all power levels, and often caused unacceptable confinement degradation, except when the neutral beam injected (NBI) power was {le} 3 MW. Formation of MARFEs on closed field lines was avoided with low safety factor (q) operation but was observed at high q, qualitatively consistent with theory. By using pellet fueling and optimizing discharge parameters to avoid each of these limits, an operational space was accessed in which density {approximately} 1.5 {times} Greenwald limit was achieved for 600 ms, and good H-mode confinement was maintained for 300 ms of the density flattop. More significantly, the density was successfully increased to the limit where a central radiative collapse was observed, the most fundamental density limit in tokamaks.« less

Density-dependent regulation of growth of BSC-1 cells in cell culture: control of growth by serum factors.

PubMed Central

Holley, R W; Armour, R; Baldwin, J H; Brown, K D; Yeh, Y C

1977-01-01

BSC-1 cells grow slowly, to high cell density, in medium with 0.1% calf serum. An increase in the serum concentration increases both the growth rate of the cells and the final cell density. The serum can be replaced to some extent by epidermal growth factor (EGF). Initiation of DNA synthesis in BSC-1 cells that have spread into a "wound" in a crowded cell layer requires the addition of a trace of serum or EGF, if the cells have previously been deprived of serum. The binding of 125I-labeled EGF to low-density and high-density BSC-1 cells has been studied. Binding is faster to low-density cells. Cells at low cell density also bind much more EGF per cell than cells at high cell density. The fraction of bound 125I-labeled EGF that is present on the cell surface as intact EGF is larger at low than at high cell density. The results indicate that the number of available EGF receptors per cell decreases drastically as the cell density increases. It is suggested that a decrease in the number of available EGF receptor sites per cell, and the accompanying decrease in sensitivity of the cells to EGF, contributes to density-dependent regulation of growth of these cells. Images PMID:303774

Density of jadeite melt under upper mantle conditions from in-situ X-ray micro-tomography measurements

NASA Astrophysics Data System (ADS)

Jing, Z.; Xu, M.; Jiang, P.; Yu, T.; Wang, Y.

2017-12-01

Knowledge of the density of silicate melts under high pressure conditions is important to our understanding of the stability and migration of melt layers in the Earth's deep mantle. A wide range of silicate melts have been studied at high pressures using the sink/float technique (e.g., Agee and Walker, 1988) and the X-ray absorption technique (e.g., Sakamaki et al, 2009). However, the effect of the Na2O component on high-pressure melt density has not been fully quantified, despite its likely presence in mantle melts. This is partly due to the experimental challenges that the Na-bearing melts often have relatively low density but high viscosity, both of which make it difficult to study using the above-mentioned techniques. In this study, we have developed a new technique based on X-ray micro-tomography to determine the density of melts at high pressures. In this technique, the volume of a melt is directly measured from the reconstructed 3-D images of the sample using computed X-ray micro-tomography. If the mass of the sample is measured using a balance or estimated from a reference density, then the density of the melt at high pressures can be calculated. Using this technique, we determined the density of jadeite melt (NaAlSi2O6) at high pressures up to 4 GPa in a Paris-Edinburg cell that can be rotated for 180 degrees under pressure. Results show that the Na2O component significantly decreases both the density and bulk modulus of silicate melts at high pressures. These data can be incorporated into a hard-sphere equation of state (Jing and Karato, 2011) to model the effect of the Na2O component on the potential density crossovers between melts produced in the mantle and the residual solid.

Prognostic Value of Tumor-Infiltrating Lymphocyte Density Assessed Using a Standardized Method Based on Molecular Subtypes and Adjuvant Chemotherapy in Invasive Breast Cancer.

PubMed

Jang, Nuri; Kwon, Hee Jung; Park, Min Hui; Kang, Su Hwan; Bae, Young Kyung

2018-04-01

This study investigated the prognostic value of tumor-infiltrating lymphocyte (TIL) density as determined by molecular subtype and receipt of adjuvant chemotherapy in invasive breast cancer (IBC). Stromal TIL densities were evaluated in 1489 IBC samples using recommendations proposed by the International TILs Working Group. Cases were allocated to high- and low-TIL density groups using a cutoff of 10%. Of the 1489 IBC patients, 427 (28.7%) were assigned to the high-TIL group and 1062 (71.3%) to the low-TIL group. High TIL density was found to be significantly associated with large tumor size (p = 0.001), high histologic grade (p < 0.001), and high Ki-67 labeling index (p < 0.001). Triple-negative and human epidermal growth factor receptor 2 (HER2)-positive subtypes had significantly higher TIL densities than luminal A or B (HER2-negative) subtypes (p < 0.001). High TIL density was significantly associated with prolonged disease-free survival (DFS) by univariate (p < 0.001) and multivariate (p < 0.001) analyses. In the low-TIL-density group, the patients who did not receive adjuvant chemotherapy showed better DFS (p < 0.001), but no such survival difference was observed in the high-TIL group (p = 0.222). For the patients who received adjuvant anthracycline, high-TIL density was found to be an independent prognostic factor of favorable DFS in the luminal B (HER2-negative; p = 0.003), HER2-positive (p = 0.019), and triple-negative (p = 0.017) subtypes. Measurements of TIL density in routine clinical practice could give useful prognostic information for the triple-negative, HER2-positive, and luminal B (HER2-negative) IBC subtypes, especially for patients administered adjuvant anthracycline.

Modeling the influence of atmospheric leading modes on the variability of the Arctic freshwater cycle

NASA Astrophysics Data System (ADS)

Niederdrenk, L.; Sein, D.; Mikolajewicz, U.

2013-12-01

Global general circulation models show remarkable differences in modeling the Arctic freshwater cycle. While they agree on the general sinks and sources of the freshwater budget, they differ largely in the magnitude of the mean values as well as in the variability of the freshwater terms. Regional models can better resolve the complex topography and small scale processes, but they are often uncoupled, thus missing the air-sea interaction. Additionally, regional models mostly use some kind of salinity restoring or flux correction, thus disturbing the freshwater budget. Our approach to investigate the Arctic hydrologic cycle and its variability is a regional atmosphere-ocean model setup, consisting of the global ocean model MPIOM with high resolution in the Arctic coupled to the regional atmosphere model REMO. The domain of the atmosphere model covers all catchment areas of the rivers draining into the Arctic. To account for all sinks and sources of freshwater in the Arctic, we include a discharge model providing terrestrial lateral waterflows. We run the model without salinity restoring but with freshwater correction, which is set to zero in the Arctic. This allows for the analysis of a closed freshwater budget in the Artic region. We perform experiments for the second half of the 20th century and use data from the global model MPIOM/ECHAM5 performed with historical conditions, that was used within the 4th Assessment Report of the IPCC, as forcing for our regional model. With this setup, we investigate how the dominant modes of large-scale atmospheric variability impact the variability in the freshwater components. We focus on the two leading empirical orthogonal functions of winter mean sea level pressure, as well as on the North Atlantic Oscillation and the Siberian High. These modes have a large impact on the Arctic Ocean circulation as well as on the solid and liquid export through Fram Strait and through the Canadian archipelago. However, they cannot explain the variability in river runoff. We find that not only winter conditions are responsible for increased river runoff, but also an enhanced summer cyclone activity, especially over Eurasia.

Satellite/Submarine Arctic Sea Ice Remote Sensing in 2004 and 2007

NASA Astrophysics Data System (ADS)

Hughes, N. E.; Wadhams, P.; Rodrigues, J.

2007-12-01

After an interlude of 8 years the U.K. Royal Navy returned to the Arctic Ocean with an under-ice mission by the submarine shape HMS Tireless in April 2004. A full environmental monitoring programme in which U.K. civilian scientists were allowed to participate was integrated into the mission. This was subsequently followed by a second expedition, in March 2007, which allowed further measurements to be acquired. These have so far been the only opportunities for civilian scientists to utilise navy submarines in the Arctic since the demise of the U.S. SCICEX programme in 2000. This paper presents some of the data collected on these new missions and uses it for validation of sea ice information derived from coincident acquisitions by modern satellite sensors such as the ESA Envisat ASAR and NASA MODIS. In both the 2004 and 2007 expeditions shape Tireless took a track north of Greenland along the latitude 85° N. This was similar to the route used for an earlier submarine-aircraft combined survey in April 1987 with which our results shall be compared. In all three missions the submarine was equipped with a standard upward-looking echosounder and sidescan for ice observations and a full range of satellite-borne, or airborne in the case of the earlier mission, microwave and optical sensors were available for validation. In this study we concentrate on the submarine track north of Greenland from the Marginal Ice Zone (MIZ) in Fram Strait through to the Lincoln Sea around 65° W. This transect encompasses a wide range of differing sea ice conditions, from the highly mobile mixture of first year and multi year ice being transported on the trans-polar drift through to the highly deformed ice north of Greenland and Ellesmere Island. The combination of submarine measurements of ice thickness and satellite/aircraft top-side measurements gives an accurate indication of how changes in the ice regime are taking place and allows the potential development of multi-sensor data fusion algorithms for improved sea ice classification and estimation of thickness.

Diagnostic Validity of High-Density Barium Sulfate in Gastric Cancer Screening: Follow-up of Screenees by Record Linkage with the Osaka Cancer Registry

PubMed Central

Yamamoto, Kenyu; Yamazaki, Hideo; Kuroda, Chikazumi; Kubo, Tsugio; Oshima, Akira; Katsuda, Toshizo; Kuwano, Tadao; Takeda, Yoshihiro

2010-01-01

Background The use of high-density barium sulfate was recommended by the Japan Society of Gastroenterological Cancer Screening (JSGCS) in 2004. We evaluated the diagnostic validity of gastric cancer screening that used high-density barium sulfate. Methods The study subjects were 171 833 residents of Osaka, Japan who underwent gastric cancer screening tests at the Osaka Cancer Prevention and Detection Center during the period from 1 January 2000 through 31 December 2001. Screening was conducted using either high-density barium sulfate (n = 48 336) or moderate-density barium sulfate (n = 123 497). The subjects were followed up and their medical records were linked to those of the Osaka Cancer Registry through 31 December 2002. The results of follow-up during 1 year were defined as the gold standard, and test performance values were calculated. Results The sensitivity and specificity of the screening test using moderate-density barium sulfate were 92.3% and 91.0%, respectively, while the sensitivity and specificity of the high-density barium test were 91.8% and 91.4%, respectively. The results of area under receiver-operating-characteristic (ROC) curve analysis revealed no significant difference between the 2 screening tests. Conclusions Screening tests using high- and moderate-density barium sulfate had similar validity, as determined by sensitivity, specificity, and ROC curve analysis. PMID:20551581

Non-high-density lipoprotein cholesterol: an important predictor of stroke and diabetes-related mortality in Japanese elderly diabetic patients.

PubMed

Araki, Atsushi; Iimuro, Satoshi; Sakurai, Takashi; Umegaki, Hiroyuki; Iijima, Katsuya; Nakano, Hiroshi; Oba, Kenzo; Yokono, Koichi; Sone, Hirohito; Yamada, Nobuhiro; Ako, Junya; Kozaki, Koichi; Miura, Hisayuki; Kashiwagi, Atsunori; Kikkawa, Ryuichi; Yoshimura, Yukio; Nakano, Tadasumi; Ohashi, Yasuo; Ito, Hideki

2012-04-01

To evaluate the association of low-density lipoprotein, high-density lipoprotein and non-high-density lipoprotein cholesterol with the risk of stroke, diabetes-related vascular events and mortality in elderly diabetes patients. This study was carried out as a post-hoc landmark analysis of a randomized, controlled, multicenter, prospective intervention trial. We included 1173 elderly type 2 diabetes patients (aged ≥ 65 years) from 39 Japanese institutions who were enrolled in the Japanese elderly diabetes intervention trial study and who could be followed up for 1 year. A landmark survival analysis was carried out in which follow up was set to start 1 year after the initial time of entry. During 6 years of follow up, there were 38 cardiovascular events, 50 strokes, 21 diabetes-related deaths and 113 diabetes-related events. High low-density lipoprotein cholesterol was associated with incident cardiovascular events, and high glycated hemoglobin was associated with strokes. After adjustment for possible covariables, non-high-density lipoprotein cholesterol showed a significant association with increased risk of stroke, diabetes-related mortality and total events. The adjusted hazard ratios (95% confidence intervals) of non-high-density lipoprotein cholesterol were 1.010 (1.001-1.018, P = 0.029) for stroke, 1.019 (1.007-1.031, P < 0.001) for diabetes-related death and 1.008 (1.002-1.014; P < 0.001) for total diabetes-related events. Higher non-high-density lipoprotein cholesterol was associated with an increased risk of stroke, diabetes-related mortality and total events in elderly diabetes patients. © 2012 Japan Geriatrics Society.

Time-resolved compression of a capsule with a cone to high density for fast-ignition laser fusion

DOE PAGES

Theobald, W.; Solodov, A. A.; Stoeckl, C.; ...

2014-12-12

The advent of high-intensity lasers enables us to recreate and study the behaviour of matter under the extreme densities and pressures that exist in many astrophysical objects. It may also enable us to develop a power source based on laser-driven nuclear fusion. Achieving such conditions usually requires a target that is highly uniform and spherically symmetric. Here we show that it is possible to generate high densities in a so-called fast-ignition target that consists of a thin shell whose spherical symmetry is interrupted by the inclusion of a metal cone. Using picosecond-time-resolved X-ray radiography, we show that we can achievemore » areal densities in excess of 300 mg cm -2 with a nanosecond-duration compression pulse -- the highest areal density ever reported for a cone-in-shell target. Such densities are high enough to stop MeV electrons, which is necessary for igniting the fuel with a subsequent picosecond pulse focused into the resulting plasma.« less

Time-resolved compression of a capsule with a cone to high density for fast-ignition laser fusion.

PubMed

Theobald, W; Solodov, A A; Stoeckl, C; Anderson, K S; Beg, F N; Epstein, R; Fiksel, G; Giraldez, E M; Glebov, V Yu; Habara, H; Ivancic, S; Jarrott, L C; Marshall, F J; McKiernan, G; McLean, H S; Mileham, C; Nilson, P M; Patel, P K; Pérez, F; Sangster, T C; Santos, J J; Sawada, H; Shvydky, A; Stephens, R B; Wei, M S

2014-12-12

The advent of high-intensity lasers enables us to recreate and study the behaviour of matter under the extreme densities and pressures that exist in many astrophysical objects. It may also enable us to develop a power source based on laser-driven nuclear fusion. Achieving such conditions usually requires a target that is highly uniform and spherically symmetric. Here we show that it is possible to generate high densities in a so-called fast-ignition target that consists of a thin shell whose spherical symmetry is interrupted by the inclusion of a metal cone. Using picosecond-time-resolved X-ray radiography, we show that we can achieve areal densities in excess of 300 mg cm(-2) with a nanosecond-duration compression pulse--the highest areal density ever reported for a cone-in-shell target. Such densities are high enough to stop MeV electrons, which is necessary for igniting the fuel with a subsequent picosecond pulse focused into the resulting plasma.

Research Investigation on Dense Scintillation Glass for Use in Total Absorption Nuclear Cascade Detectors

NASA Technical Reports Server (NTRS)

Hensler, J. R.

1973-01-01

Three approaches to the development of a high density scintillation glass were investigated: They include the increase of density of glass systems containing cerium - the only systems which were known to show scintillation, the testing of a novel silicate glass system containing significant concentrations of silver produced by ion exchange and never tested previously, and the hot pressing of a diphasic compact of low density scintillation glass with high density passive glass. In first two cases, while ultraviolet excited fluorescence was maintained in the glasses showing high density, scintillation response to high energy particles was not retained in the case of the cerium containing glasses or developed in the case of the silver containing glasses. In the case of the compacts, the extremely long path length caused by the multiple internal reflections which occur in such a body resulted in attenuation even with glasses of high specific transmission. It is not clear why the scintillation efficiency is not maintained in the higher density cerium containing glasses.

14 CFR 93.227 - Slot use and loss.

Code of Federal Regulations, 2010 CFR

2010-01-01

... Operations at High Density Traffic Airports § 93.227 Slot use and loss. (a) Except as provided in paragraphs... commuter operator or other person holding a slot at a high density airport shall, within 14 days after the... High Density Traffic Airport on Thanksgiving Day, the Friday following Thanksgiving Day, and the period...

14 CFR 93.227 - Slot use and loss.

Code of Federal Regulations, 2011 CFR

2011-01-01

... Operations at High Density Traffic Airports § 93.227 Slot use and loss. (a) Except as provided in paragraphs... commuter operator or other person holding a slot at a high density airport shall, within 14 days after the... High Density Traffic Airport on Thanksgiving Day, the Friday following Thanksgiving Day, and the period...

14 CFR 93.227 - Slot use and loss.

Code of Federal Regulations, 2014 CFR

2014-01-01

... Operations at High Density Traffic Airports § 93.227 Slot use and loss. (a) Except as provided in paragraphs... commuter operator or other person holding a slot at a high density airport shall, within 14 days after the... High Density Traffic Airport on Thanksgiving Day, the Friday following Thanksgiving Day, and the period...

14 CFR 93.227 - Slot use and loss.

Code of Federal Regulations, 2012 CFR

2012-01-01

... Operations at High Density Traffic Airports § 93.227 Slot use and loss. (a) Except as provided in paragraphs... commuter operator or other person holding a slot at a high density airport shall, within 14 days after the... High Density Traffic Airport on Thanksgiving Day, the Friday following Thanksgiving Day, and the period...

14 CFR 93.227 - Slot use and loss.

Code of Federal Regulations, 2013 CFR

2013-01-01

... Operations at High Density Traffic Airports § 93.227 Slot use and loss. (a) Except as provided in paragraphs... commuter operator or other person holding a slot at a high density airport shall, within 14 days after the... High Density Traffic Airport on Thanksgiving Day, the Friday following Thanksgiving Day, and the period...

Flexible asymmetric supercapacitors with high energy and high power density in aqueous electrolytes.

PubMed

Cheng, Yingwen; Zhang, Hongbo; Lu, Songtao; Varanasi, Chakrapani V; Liu, Jie

2013-02-07

Supercapacitors with both high energy and high power densities are critical for many practical applications. In this paper, we discuss the design and demonstrate the fabrication of flexible asymmetric supercapacitors based on nanocomposite electrodes of MnO(2), activated carbon, carbon nanotubes and graphene. The combined unique properties of each of these components enable highly flexible and mechanically strong films that can serve as electrodes directly without using any current collectors or binders. Using these flexible electrodes and a roll-up approach, asymmetric supercapacitors with 2 V working voltage were successfully fabricated. The fabricated device showed excellent rate capability, with 78% of the original capacitance retained when the scan rate was increased from 2 mV s(-1) to 500 mV s(-1). Owing to the unique composite structure, these supercapacitors were able to deliver high energy density (24 W h kg(-1)) under high power density (7.8 kW kg(-1)) conditions. These features could enable supercapacitor based energy storage systems to be very attractive for a variety of critical applications, such as the power sources in hybrid electric vehicles and the back-up powers for wind and solar energy, where both high energy density and high power density are required.

Elastic Behavior and Platelet Retraction in Low- and High-Density Fibrin Gels

PubMed Central

Wufsus, Adam R.; Rana, Kuldeepsinh; Brown, Andrea; Dorgan, John R.; Liberatore, Matthew W.; Neeves, Keith B.

2015-01-01

Fibrin is a biopolymer that gives thrombi the mechanical strength to withstand the forces imparted on them by blood flow. Importantly, fibrin is highly extensible, but strain hardens at low deformation rates. The density of fibrin in clots, especially arterial clots, is higher than that in gels made at plasma concentrations of fibrinogen (3–10 mg/mL), where most rheology studies have been conducted. Our objective in this study was to measure and characterize the elastic regimes of low (3–10 mg/mL) and high (30–100 mg/mL) density fibrin gels using shear and extensional rheology. Confocal microscopy of the gels shows that fiber density increases with fibrinogen concentration. At low strains, fibrin gels act as thermal networks independent of fibrinogen concentration. Within the low-strain regime, one can predict the mesh size of fibrin gels by the elastic modulus using semiflexible polymer theory. Significantly, this provides a link between gel mechanics and interstitial fluid flow. At moderate strains, we find that low-density fibrin gels act as nonaffine mechanical networks and transition to affine mechanical networks with increasing strains within the moderate regime, whereas high-density fibrin gels only act as affine mechanical networks. At high strains, the backbone of individual fibrin fibers stretches for all fibrin gels. Platelets can retract low-density gels by >80% of their initial volumes, but retraction is attenuated in high-density fibrin gels and with decreasing platelet density. Taken together, these results show that the nature of fibrin deformation is a strong function of fibrin fiber density, which has ramifications for the growth, embolization, and lysis of thrombi. PMID:25564864

Serum osteoprotegerin levels and mammographic density among high-risk women.

PubMed

Moran, Olivia; Zaman, Tasnim; Eisen, Andrea; Demsky, Rochelle; Blackmore, Kristina; Knight, Julia A; Elser, Christine; Ginsburg, Ophira; Zbuk, Kevin; Yaffe, Martin; Narod, Steven A; Salmena, Leonardo; Kotsopoulos, Joanne

2018-06-01

Mammographic density is a risk factor for breast cancer but the mechanism behind this association is unclear. The receptor activator of nuclear factor κB (RANK)/RANK ligand (RANKL) pathway has been implicated in the development of breast cancer. Given the role of RANK signaling in mammary epithelial cell proliferation, we hypothesized this pathway may also be associated with mammographic density. Osteoprotegerin (OPG), a decoy receptor for RANKL, is known to inhibit RANK signaling. Thus, it is of interest to evaluate whether OPG levels modify breast cancer risk through mammographic density. We quantified serum OPG levels in 57 premenopausal and 43 postmenopausal women using an enzyme-linked immunosorbent assay (ELISA). Cumulus was used to measure percent density, dense area, and non-dense area for each mammographic image. Subjects were classified into high versus low OPG levels based on the median serum OPG level in the entire cohort (115.1 pg/mL). Multivariate models were used to assess the relationship between serum OPG levels and the measures of mammographic density. Serum OPG levels were not associated with mammographic density among premenopausal women (P ≥ 0.42). Among postmenopausal women, those with low serum OPG levels had higher mean percent mammographic density (20.9% vs. 13.7%; P = 0.04) and mean dense area (23.4 cm 2 vs. 15.2 cm 2 ; P = 0.02) compared to those with high serum OPG levels after covariate adjustment. These findings suggest that low OPG levels may be associated with high mammographic density, particularly in postmenopausal women. Targeting RANK signaling may represent a plausible, non-surgical prevention option for high-risk women with high mammographic density, especially those with low circulating OPG levels.

Departure Mechanisms for Host Search on High-Density Patches by the Meteorus pulchricornis

PubMed Central

Sheng, Sheng; Feng, Sufang; Meng, Ling; Li, Baoping

2014-01-01

Abstract Less attention has been paid to the parasitoid–host system in which the host occurs in considerably high density with a hierarchical patch structure in studies on time allocation strategies of parasitoids. This study used the parasitoid Meteorus pulchricornis (Wesmael) (Hymenoptera: Braconidae) and the Oriental leafworm, Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae) as the parasitoids–host model system to investigate patch-leaving mechanisms as affected by the high-host density, hierarchical patch structure, and foraging behaviors on both former and current patches. The results showed that three out of eight covariates tested had significant effects on the patch-leaving tendency, including the host density, ovipositor insertion, and host rejection on the current patch. The parasitoid paid more visits to the patch with high-density hosts. While the patch with higher host densities decreased the leaving tendency, the spatial distribution of hosts examined had no effect on the leaving tendency. Both oviposition and host rejection decreased the patch-leaving tendency. The variables associated with the former patch, such as the host density and number of ovipositor insertions, however, did not have an effect on the leaving tendency. Our study suggested that M. pulchricornis females may use an incremental mechanism to exploit high-density patches to the fullest. PMID:25502040

Series asymmetric supercapacitors based on free-standing inner-connection electrodes for high energy density and high output voltage

NASA Astrophysics Data System (ADS)

Tao, Jiayou; Liu, Nishuang; Rao, Jiangyu; Ding, Longwei; Al Bahrani, Majid Raissan; Li, Luying; Su, Jun; Gao, Yihua

2014-11-01

Asymmetric supercapacitors (ASCs) based on free-standing membranes with high energy density and high output voltage are reported. MnO2 nanowire/carbon nanotube (CNT) composites and MoO3 nanobelt/CNT composites are selected as the anode and the cathode materials of the devices, respectively. The ASC has a high volumetric capacitance of 50.2 F cm-3 at a scan rate of 2 mV s-1 and a high operation voltage window of 2.0 V. Especially, after a middle layer with an inner-connection structure was inserted between the anode and the cathode, the output voltage of the whole device can achieve 4.0 V. The full cell of series ASCs (SASC) with an inner-connection middle layer has a high energy density of 28.6 mW h cm-3 at a power density of 261.4 mW cm-3, and exhibits excellent cycling performance of 99.6% capacitance retention over 10 000 cycles. This strategy of designing the hybridized structure for SASCs provides a promising route for next-generation SCs with high energy density and high output voltage.Asymmetric supercapacitors (ASCs) based on free-standing membranes with high energy density and high output voltage are reported. MnO2 nanowire/carbon nanotube (CNT) composites and MoO3 nanobelt/CNT composites are selected as the anode and the cathode materials of the devices, respectively. The ASC has a high volumetric capacitance of 50.2 F cm-3 at a scan rate of 2 mV s-1 and a high operation voltage window of 2.0 V. Especially, after a middle layer with an inner-connection structure was inserted between the anode and the cathode, the output voltage of the whole device can achieve 4.0 V. The full cell of series ASCs (SASC) with an inner-connection middle layer has a high energy density of 28.6 mW h cm-3 at a power density of 261.4 mW cm-3, and exhibits excellent cycling performance of 99.6% capacitance retention over 10 000 cycles. This strategy of designing the hybridized structure for SASCs provides a promising route for next-generation SCs with high energy density and high output voltage. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr04819a

Implementing an Inexpensive and Accurate Introductory Gas Density Activity with High School Students

ERIC Educational Resources Information Center

Cunningham, W. Patrick; Joseph, Christopher; Morey, Samantha; Santos Romo, Ana; Shope, Cullen; Strang, Jonathan; Yang, Kevin

2015-01-01

A simplified activity examined gas density while employing cost-efficient syringes in place of traditional glass bulbs. The exercise measured the density of methane, with very good accuracy and precision, in both first-year high school and AP chemistry settings. The participating students were tasked with finding the density of a gas. The…

High speed FPGA-based Phasemeter for the far-infrared laser interferometers on EAST

NASA Astrophysics Data System (ADS)

Yao, Y.; Liu, H.; Zou, Z.; Li, W.; Lian, H.; Jie, Y.

2017-12-01

The far-infrared laser-based HCN interferometer and POlarimeter/INTerferometer\\break (POINT) system are important diagnostics for plasma density measurement on EAST tokamak. Both HCN and POINT provide high spatial and temporal resolution of electron density measurement and used for plasma density feedback control. The density is calculated by measuring the real-time phase difference between the reference beams and the probe beams. For long-pulse operations on EAST, the calculation of density has to meet the requirements of Real-Time and high precision. In this paper, a Phasemeter for far-infrared laser-based interferometers will be introduced. The FPGA-based Phasemeter leverages fast ADCs to obtain the three-frequency signals from VDI planar-diode Mixers, and realizes digital filters and an FFT algorithm in FPGA to provide real-time, high precision electron density output. Implementation of the Phasemeter will be helpful for the future plasma real-time feedback control in long-pulse discharge.

Benign Breast Disease, Mammographic Breast Density, and the Risk of Breast Cancer

PubMed Central

2013-01-01

Background Benign breast disease and high breast density are prevalent, strong risk factors for breast cancer. Women with both risk factors may be at very high risk. Methods We included 42818 women participating in the Breast Cancer Surveillance Consortium who had no prior diagnosis of breast cancer and had undergone at least one benign breast biopsy and mammogram; 1359 women developed incident breast cancer in 6.1 years of follow-up (78.1% invasive, 21.9% ductal carcinoma in situ). We calculated hazard ratios (HRs) using Cox regression analysis. The referent group was women with nonproliferative changes and average density. All P values are two-sided. Results Benign breast disease and breast density were independently associated with breast cancer. The combination of atypical hyperplasia and very high density was uncommon (0.6% of biopsies) but was associated with the highest risk for breast cancer (HR = 5.34; 95% confidence interval [CI] = 3.52 to 8.09, P < .001). Proliferative disease without atypia (25.6% of biopsies) was associated with elevated risk that varied little across levels of density: average (HR = 1.37; 95% CI = 1.11 to 1.69, P = .003), high (HR = 2.02; 95% CI = 1.68 to 2.44, P < .001), or very high (HR = 2.05; 95% CI = 1.54 to 2.72, P < .001). Low breast density (4.5% of biopsies) was associated with low risk (HRs <1) for all benign pathology diagnoses. Conclusions Women with high breast density and proliferative benign breast disease are at very high risk for future breast cancer. Women with low breast density are at low risk, regardless of their benign pathologic diagnosis. PMID:23744877

Benign breast disease, mammographic breast density, and the risk of breast cancer.

PubMed

Tice, Jeffrey A; O'Meara, Ellen S; Weaver, Donald L; Vachon, Celine; Ballard-Barbash, Rachel; Kerlikowske, Karla

2013-07-17

Benign breast disease and high breast density are prevalent, strong risk factors for breast cancer. Women with both risk factors may be at very high risk. We included 42818 women participating in the Breast Cancer Surveillance Consortium who had no prior diagnosis of breast cancer and had undergone at least one benign breast biopsy and mammogram; 1359 women developed incident breast cancer in 6.1 years of follow-up (78.1% invasive, 21.9% ductal carcinoma in situ). We calculated hazard ratios (HRs) using Cox regression analysis. The referent group was women with nonproliferative changes and average density. All P values are two-sided. Benign breast disease and breast density were independently associated with breast cancer. The combination of atypical hyperplasia and very high density was uncommon (0.6% of biopsies) but was associated with the highest risk for breast cancer (HR = 5.34; 95% confidence interval [CI] = 3.52 to 8.09, P < .001). Proliferative disease without atypia (25.6% of biopsies) was associated with elevated risk that varied little across levels of density: average (HR = 1.37; 95% CI = 1.11 to 1.69, P = .003), high (HR = 2.02; 95% CI = 1.68 to 2.44, P < .001), or very high (HR = 2.05; 95% CI = 1.54 to 2.72, P < .001). Low breast density (4.5% of biopsies) was associated with low risk (HRs <1) for all benign pathology diagnoses. Women with high breast density and proliferative benign breast disease are at very high risk for future breast cancer. Women with low breast density are at low risk, regardless of their benign pathologic diagnosis.

The Three-part Structure of a Filament-unrelated Solar Coronal Mass Ejection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Song, H. Q.; Chen, Y.; Wang, B.

Coronal mass ejections (CMEs) often exhibit the typical three-part structure in the corona when observed with white-light coronagraphs, i.e., the bright leading front, dark cavity, and bright core, corresponding to a high-low-high density sequence. As CMEs result from eruptions of magnetic flux ropes (MFRs), which can possess either lower (e.g., coronal-cavity MFRs) or higher (e.g., hot-channel MFRs) density compared to their surroundings in the corona, the traditional opinion regards the three-part structure as the manifestations of coronal plasma pileup (high density), coronal-cavity MFR (low density), and filament (high density) contained in the trailing part of MFR, respectively. In this paper,more » we demonstrate that filament-unrelated CMEs can also exhibit the classical three-part structure. The observations were made from different perspectives through an event that occurred on 2011 October 4. The CME cavity corresponds to the low-density zone between the leading front and the high-density core, and it is obvious in the low corona and gradually becomes fuzzy when propagating outward. The bright core corresponds to a high-density structure that is suggested to be an erupting MFR. The MFR is recorded from both edge-on and face-on perspectives, exhibiting different morphologies that are due to projection effects. We stress that the zone (MFR) with lower (higher) density in comparison to the surroundings can appear as the dark cavity (bright core) when observed through white-light coronagraphs, which is not necessarily the coronal-cavity MFR (erupted filament).« less

Concrete density estimation by rebound hammer method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ismail, Mohamad Pauzi bin, E-mail: pauzi@nm.gov.my; Masenwat, Noor Azreen bin; Sani, Suhairy bin

Concrete is the most common and cheap material for radiation shielding. Compressive strength is the main parameter checked for determining concrete quality. However, for shielding purposes density is the parameter that needs to be considered. X- and -gamma radiations are effectively absorbed by a material with high atomic number and high density such as concrete. The high strength normally implies to higher density in concrete but this is not always true. This paper explains and discusses the correlation between rebound hammer testing and density for concrete containing hematite aggregates. A comparison is also made with normal concrete i.e. concrete containingmore » crushed granite.« less

Increasing leaf vein density by mutagenesis: laying the foundations for C4 rice.

PubMed

Feldman, Aryo B; Murchie, Erik H; Leung, Hei; Baraoidan, Marietta; Coe, Robert; Yu, Su-May; Lo, Shuen-Fang; Quick, William P

2014-01-01

A high leaf vein density is both an essential feature of C4 photosynthesis and a foundation trait to C4 evolution, ensuring the optimal proportion and proximity of mesophyll and bundle sheath cells for permitting the rapid exchange of photosynthates. Two rice mutant populations, a deletion mutant library with a cv. IR64 background (12,470 lines) and a T-DNA insertion mutant library with a cv. Tainung 67 background (10,830 lines), were screened for increases in vein density. A high throughput method with handheld microscopes was developed and its accuracy was supported by more rigorous microscopy analysis. Eight lines with significantly increased leaf vein densities were identified to be used as genetic stock for the global C4 Rice Consortium. The candidate population was shown to include both shared and independent mutations and so more than one gene controlled the high vein density phenotype. The high vein density trait was found to be linked to a narrow leaf width trait but the linkage was incomplete. The more genetically robust narrow leaf width trait was proposed to be used as a reliable phenotypic marker for finding high vein density variants in rice in future screens.

A multi-emitter fitting algorithm for potential live cell super-resolution imaging over a wide range of molecular densities.

PubMed

Takeshima, T; Takahashi, T; Yamashita, J; Okada, Y; Watanabe, S

2018-05-25

Multi-emitter fitting algorithms have been developed to improve the temporal resolution of single-molecule switching nanoscopy, but the molecular density range they can analyse is narrow and the computation required is intensive, significantly limiting their practical application. Here, we propose a computationally fast method, wedged template matching (WTM), an algorithm that uses a template matching technique to localise molecules at any overlapping molecular density from sparse to ultrahigh density with subdiffraction resolution. WTM achieves the localization of overlapping molecules at densities up to 600 molecules μm -2 with a high detection sensitivity and fast computational speed. WTM also shows localization precision comparable with that of DAOSTORM (an algorithm for high-density super-resolution microscopy), at densities up to 20 molecules μm -2 , and better than DAOSTORM at higher molecular densities. The application of WTM to a high-density biological sample image demonstrated that it resolved protein dynamics from live cell images with subdiffraction resolution and a temporal resolution of several hundred milliseconds or less through a significant reduction in the number of camera images required for a high-density reconstruction. WTM algorithm is a computationally fast, multi-emitter fitting algorithm that can analyse over a wide range of molecular densities. The algorithm is available through the website. https://doi.org/10.17632/bf3z6xpn5j.1. © 2018 The Authors. Journal of Microscopy published by JohnWiley & Sons Ltd on behalf of Royal Microscopical Society.

Initial glenoid fixation using two different reverse shoulder designs with an equivalent center of rotation in a low-density and high-density bone substitute.

PubMed

Stroud, Nicholas J; DiPaola, Matthew J; Martin, Brian L; Steiler, Cindy A; Flurin, Pierre-Henri; Wright, Thomas W; Zuckerman, Joseph D; Roche, Christopher P

2013-11-01

Numerous glenoid implant designs have been introduced into the global marketplace in recent years; however, little comparative biomechanical data exist to substantiate one design consideration over another. This study dynamically evaluated reverse shoulder glenoid baseplate fixation and compared the initial fixation associated with 2 reverse shoulder designs having an equivalent center of rotation in low-density and high-density bone substitute substrates. Significant differences in fixation were observed between implant designs, where the circular-porous reverse shoulder was associated with approximately twice the micromotion per equivalent test than the oblong-grit-blasted design. Additionally, 6 of the 7 circular-porous reverse shoulders failed catastrophically in the low-density bone model at an average of 2603 ± 981 cycles. None of the oblong-grit-blasted designs failed in the low-or high-density bone models and none of the circular-porous designs failed in the high-density bone models after 10,000 cycles of loading. These results demonstrate that significant differences in initial fixation exist between reverse shoulder implants having an equivalent center of rotation and suggest that design parameters, other than the position of the center of rotation, significantly affect fixation in low-density and high-density polyurethane bone substitutes. Subtle changes in glenoid baseplate design can dramatically affect fixation, particularly in low-density bone substitutes that are intended to simulate the bone quality of the recipient population for reverse shoulders. Copyright © 2013 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.

Serum cholesterol and risk of lower urinary tract symptoms progression: Results from the Reduction by Dutasteride of Prostate Cancer Events study.

PubMed

Feng, Tom; Howard, Lauren E; Vidal, Adriana C; Moreira, Daniel M; Castro-Santamaria, Ramiro; Andriole, Gerald L; Freedland, Stephen J

2017-02-01

To determine if cholesterol is a risk factor for the development of lower urinary tract symptoms in asymptomatic men. A post-hoc analysis of the Reduction by Dutasteride of Prostate Cancer Events (REDUCE) study was carried out in 2323 men with baseline International Prostate Symptom Score <8 and not taking benign prostatic hyperplasia or cholesterol medications. Cox proportion models were used to test the association between cholesterol, high-density lipoprotein, low-density lipoprotein and the cholesterol : high-density lipoprotein ratio with incident lower urinary tract symptoms, defined as first report of medical treatment, surgery or two reports of an International Prostate Symptom Score >14. A total of 253 men (10.9%) developed incident lower urinary tract symptoms. On crude analysis, higher high-density lipoprotein was associated with a decreased lower urinary tract symptoms risk (hazard ratio 0.89, P = 0.024), whereas total cholesterol and low-density lipoprotein showed no association. After multivariable adjustment, the association between high-density lipoprotein and incident lower urinary tract symptoms remained significant (hazard ratio 0.89, P = 0.044), whereas no association was observed for low-density lipoprotein (P = 0.611). There was a trend for higher cholesterol to be linked with higher lower urinary tract symptoms risk, though this was not statistically significant (hazard ratio 1.04, P = 0.054). A higher cholesterol : high-density lipoprotein ratio was associated with increased lower urinary tract symptoms risk on crude (hazard ratio 1.11, P = 0.016) and adjusted models (hazard ratio 1.12, P = 0.012). Among asymptomatic men participating in the REDUCE study, higher cholesterol was associated with increased incident lower urinary tract symptoms risk, though the association was not significant. A higher cholesterol : high-density lipoprotein ratio was associated with increased incident lower urinary tract symptoms, whereas higher high-density lipoprotein was protective. These findings suggest dyslipidemia might play a role in lower urinary tract symptoms progression. © 2016 The Japanese Urological Association.

Seed-predator satiation and Janzen-Connell effects vary with spatial scales for seed-feeding insects.

PubMed

Xiao, Zhishu; Mi, Xiangcheng; Holyoak, Marcel; Xie, Wenhua; Cao, Ke; Yang, Xifu; Huang, Xiaoqun; Krebs, Charles J

2017-01-01

The Janzen-Connell model predicts that common species suffer high seed predation from specialized natural enemies as a function of distance from parent trees, and consequently as a function of conspecific density, whereas the predator satiation hypothesis predicts that seed attack is reduced due to predator satiation at high seed densities. Pre-dispersal predation by insects was studied while seeds are still on parent trees, which represents a frequently overlooked stage in which seed predation occurs. Reproductive tree density and seed production were investigated from ten Quercus serrata populations located in south-west China, quantifying density-dependent pre-dispersal seed predation over two years by three insect groups. Acorn infestation was nearly twice as high in the low-seed year as that in the high-seed year, with considerable spatio-temporal variation in the direction and magnitude of density-dependent pre-dispersal seed predation evident. Across whole populations of trees, a high density of reproductive trees caused predator satiation and reduced insect attack in the high-seed year. Within individual trees, and consistent with the Janzen-Connell model, overall insect seed predation was positively correlated with seed production in the low-seed year. In addition, there was variation among insect taxa, with positive density-dependent seed predation by Curculio weevils in the high-seed year and moths in the low-seed year, but apparent density independence by Cyllorhynchites weevils in both years. The overall trend of negative density-dependent, pre-dispersal seed predation suggests that predator satiation limited the occurrence of Janzen-Connell effects across Q. serrata populations. Such effects may have large impacts on plant population dynamics and tree diversity, depending on the extent to which they are reduced by counteracting positive density-dependent predation for seeds on individual trees and other factors affecting successful recruitment. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Energy storage device with large charge separation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holme, Timothy P.; Prinz, Friedrich B.; Iancu, Andrei T.

High density energy storage in semiconductor devices is provided. There are two main aspects of the present approach. The first aspect is to provide high density energy storage in semiconductor devices based on formation of a plasma in the semiconductor. The second aspect is to provide high density energy storage based on charge separation in a p-n junction.

Fitness, Heart Disease, and High-Density Lipoproteins: A Look at the Relationships.

ERIC Educational Resources Information Center

McCunney, Robert J.

1987-01-01

The role of fitness in preventing coronary heart disease is explored. Research on high-density lipoprotein, which has been found to be one of the most critical determinants of risk, is reviewed. The relationship between fitness, high-density lipoprotein, and coronary heart disease is assessed, and clinical implications are spelled out. (MT)

Energy storage device with large charge separation

DOEpatents

Holme, Timothy P.; Prinz, Friedrich B.; Iancu, Andrei

2016-04-12

High density energy storage in semiconductor devices is provided. There are two main aspects of the present approach. The first aspect is to provide high density energy storage in semiconductor devices based on formation of a plasma in the semiconductor. The second aspect is to provide high density energy storage based on charge separation in a p-n junction.

7 CFR 319.8-8 - Lint, linters, and waste.

Code of Federal Regulations, 2012 CFR

2012-01-01

... Importation and Entry of Cotton and Covers § 319.8-8 Lint, linters, and waste. (a) Compressed to high density. (1)(i) Entry of lint, linters, and waste, compressed to high density, will be authorized subject to... to high density arriving at a port in the State of California where there are no approved fumigation...

Metabolic active-high density VERO cell cultures on microcarriers following apoptosis prevention by galactose/glutamine feeding.

PubMed

Mendonça, Ronaldo Z; Arrózio, Sara J; Antoniazzi, Marta M; Ferreira, Jorge M C; Pereira, Carlos A

2002-07-17

The control of cell death occurring in high density cultures performed in bioreactors is an important factor in production processes. In this work, medium nutrient removal or feeding was used to determine at which extension apoptosis could be, respectively, involved or prevented in VERO cell cultures on microcarriers. Glutamine and galactose present in the VERO cell culture medium was consumed after, respectively, 6 and 12 days of culture. Kinetics studies showed that fresh medium replacement and, to some extent, galactose or glutamine depleted-fresh medium replacement provided a nutritional environment, allowing the VERO cell cultures to attain high densities. Galactose was shown to be a more critical nutrient when cultures reached a high density. In agreement with that, VERO cell cultures supplemented with galactose and/or glutamine were shown to confirm previous findings and, again at high densities, galactose was shown to be a critical nutrient for VERO cell growth. These observations also indicated that in VERO cell cultures, for feeding purposes, the glutamine could be replaced by galactose. The inverse was not true and led, at high densities, to a decrease of cell viability. In the absence of glutamine and galactose, apoptosis was observed in VERO cell cultures by cytofluorometry, Acridine orange staining or light and electron microscopy, reaching high levels when compared to cultures performed with complete medium. VERO cells apoptosis process could be prevented by the galactose and/or glutamine feeding and, at high densities, galactose was more efficient in protecting the cultures. These cultures, prevented from apoptosis, were shown to synthesize high levels of measles virus following infection. Our data show that apoptosis prevention by glutamine/galactose feeding, led to high productive and metabolic active VERO cell cultures, as indicated by the high cell density obtained and the virus multiplication leading to higher virus titers.

Prior-knowledge-based spectral mixture analysis for impervious surface mapping

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Jinshui; He, Chunyang; Zhou, Yuyu

2014-01-03

In this study, we developed a prior-knowledge-based spectral mixture analysis (PKSMA) to map impervious surfaces by using endmembers derived separately for high- and low-density urban regions. First, an urban area was categorized into high- and low-density urban areas, using a multi-step classification method. Next, in high-density urban areas that were assumed to have only vegetation and impervious surfaces (ISs), the Vegetation-Impervious model (V-I) was used in a spectral mixture analysis (SMA) with three endmembers: vegetation, high albedo, and low albedo. In low-density urban areas, the Vegetation-Impervious-Soil model (V-I-S) was used in an SMA analysis with four endmembers: high albedo, lowmore » albedo, soil, and vegetation. The fraction of IS with high and low albedo in each pixel was combined to produce the final IS map. The root mean-square error (RMSE) of the IS map produced using PKSMA was about 11.0%, compared to 14.52% using four-endmember SMA. Particularly in high-density urban areas, PKSMA (RMSE = 6.47%) showed better performance than four-endmember (15.91%). The results indicate that PKSMA can improve IS mapping compared to traditional SMA by using appropriately selected endmembers and is particularly strong in high-density urban areas.« less

Effects of Biomass Accessibility and Klason Lignin Contents during Consolidated Bioprocessing in Populus trichocarpa

DOE Office of Scientific and Technical Information (OSTI.GOV)

Akinosho, Hannah; Dumitrache, Alexandru; Natzke, Jace

The bacterium Clostridium thermocellum offers a distinct and integrated approach to ethanol production through consolidated bioprocessing (CBP). The Simons’ stain technique, which assays the accessibility of lignocellulosic biomass, has been traditionally applied to fungal cellulase systems; however, its application to CBP has not been fully explored. For this reason, the structural properties of eight Populus trichocarpa with either high or low biomass densities were compared in this paper to determine bioconversion differences during separate hydrolysis and fermentation (SHF) and CBP with C. thermocellum. Simons’ staining generally identifies low density poplar as more accessible than high density poplar. Additionally, low densitymore » P. trichocarpa generally contained less Klason lignin than high density poplar. SHF and CBP treatments consistently identified BESC-7 (high density, low accessibility, low surface roughness) as a low ethanol yielding biomass and GW-9914 (low density, high accessibility, high surface roughness) as a high ethanol yielding biomass. Upon further investigation, BESC-7 also contained a high Klason lignin content (~25%), while GW-9914 had a low lignin content (~20%). Cellulose degree of polymerization (DP) measurements exhibited a weak linear correlation with accessibility (r 2 = 0.17). Finally, therefore, the ethanol yields were correlated with accessibility and lignin content extremes but not cellulose DP.« less

Effects of Biomass Accessibility and Klason Lignin Contents during Consolidated Bioprocessing in Populus trichocarpa

DOE PAGES

Akinosho, Hannah; Dumitrache, Alexandru; Natzke, Jace; ...

2017-04-26

The bacterium Clostridium thermocellum offers a distinct and integrated approach to ethanol production through consolidated bioprocessing (CBP). The Simons’ stain technique, which assays the accessibility of lignocellulosic biomass, has been traditionally applied to fungal cellulase systems; however, its application to CBP has not been fully explored. For this reason, the structural properties of eight Populus trichocarpa with either high or low biomass densities were compared in this paper to determine bioconversion differences during separate hydrolysis and fermentation (SHF) and CBP with C. thermocellum. Simons’ staining generally identifies low density poplar as more accessible than high density poplar. Additionally, low densitymore » P. trichocarpa generally contained less Klason lignin than high density poplar. SHF and CBP treatments consistently identified BESC-7 (high density, low accessibility, low surface roughness) as a low ethanol yielding biomass and GW-9914 (low density, high accessibility, high surface roughness) as a high ethanol yielding biomass. Upon further investigation, BESC-7 also contained a high Klason lignin content (~25%), while GW-9914 had a low lignin content (~20%). Cellulose degree of polymerization (DP) measurements exhibited a weak linear correlation with accessibility (r 2 = 0.17). Finally, therefore, the ethanol yields were correlated with accessibility and lignin content extremes but not cellulose DP.« less

High Discharge Energy Density at Low Electric Field Using an Aligned Titanium Dioxide/Lead Zirconate Titanate Nanowire Array

PubMed Central

Zhang, Dou; Liu, Weiwei; Guo, Ru; Zhou, Kechao

2017-01-01

Abstract Polymer‐based capacitors with high energy density have attracted significant attention in recent years due to their wide range of potential applications in electronic devices. However, the obtained high energy density is predominantly dependent on high applied electric field, e.g., 400–600 kV mm−1, which may bring more challenges relating to the failure probability. Here, a simple two‐step method for synthesizing titanium dioxide/lead zirconate titanate nanowire arrays is exploited and a demonstration of their ability to achieve high discharge energy density capacitors for low operating voltage applications is provided. A high discharge energy density of 6.9 J cm−3 is achieved at low electric fields, i.e., 143 kV mm−1, which is attributed to the high relative permittivity of 218.9 at 1 kHz and high polarization of 23.35 µC cm−2 at this electric field. The discharge energy density obtained in this work is the highest known for a ceramic/polymer nanocomposite at such a low electric field. The novel nanowire arrays used in this work are applicable to a wide range of fields, such as energy harvesting, energy storage, and photocatalysis. PMID:29610724

Facilitation in Caribbean coral reefs: high densities of staghorn coral foster greater coral condition and reef fish composition.

PubMed

Huntington, Brittany E; Miller, Margaret W; Pausch, Rachel; Richter, Lee

2017-05-01

Recovery of the threatened staghorn coral (Acropora cervicornis) is posited to play a key role in Caribbean reef resilience. At four Caribbean locations (including one restored and three extant populations), we quantified characteristics of contemporary staghorn coral across increasing conspecific densities, and investigated a hypothesis of facilitation between staghorn coral and reef fishes. High staghorn densities in the Dry Tortugas exhibited significantly less partial mortality, higher branch growth, and supported greater fish abundances compared to lower densities within the same population. In contrast, partial mortality, branch growth, and fish community composition did not vary with staghorn density at the three other study locations where staghorn densities were lower overall. This suggests that density-dependent effects between the coral and fish community may only manifest at high staghorn densities. We then evaluated one facilitative mechanism for such density-dependence, whereby abundant fishes sheltering in dense staghorn aggregations deliver nutrients back to the coral, fueling faster coral growth, thereby creating more fish habitat. Indeed, dense staghorn aggregations within the Dry Tortugas exhibited significantly higher growth rates, tissue nitrogen, and zooxanthellae densities than sparse aggregations. Similarly, higher tissue nitrogen was induced in a macroalgae bioassay outplanted into the same dense and sparse aggregations, confirming greater bioavailability of nutrients at high staghorn densities. Our findings inform staghorn restoration efforts, suggesting that the most effective targets may be higher coral densities than previously thought. These coral-dense aggregations may reap the benefits of positive facilitation between the staghorn and fish community, favoring the growth and survivorship of this threatened species.

Ocular anatomy, ganglion cell distribution and retinal resolution of a killer whale (Orcinus orca).

PubMed

Mass, Alla M; Supin, Alexander Y; Abramov, Andrey V; Mukhametov, Lev M; Rozanova, Elena I

2013-01-01

Retinal topography, cell density and sizes of ganglion cells in the killer whale (Orcinus orca) were analyzed in retinal whole mounts stained with cresyl violet. A distinctive feature of the killer whale's retina is the large size of ganglion cells and low cell density compared to terrestrial mammals. The ganglion cell diameter ranged from 8 to 100 µm, with the majority of cells within a range of 20-40 µm. The topographic distribution of ganglion cells displayed two spots of high cell density located in the temporal and nasal quadrants, 20 mm from the optic disk. The high-density areas were connected by a horizontal belt-like area passing below the optic disk of the retina. Peak cell densities in these areas were evaluated. Mean peak cell densities were 334 and 288 cells/mm(2) in the temporal and nasal high-density areas, respectively. With a posterior nodal distance of 19.5 mm, these high-density data predict a retinal resolution of 9.6' (3.1 cycles/deg.) and 12.6' (2.4 cycles/deg.) in the temporal and nasal areas, respectively, in water. Copyright © 2012 S. Karger AG, Basel.

Numerical Study on Density Gradient Carbon-Carbon Composite for Vertical Launching System

NASA Astrophysics Data System (ADS)

Yoon, Jin-Young; Kim, Chun-Gon; Lim, Juhwan

2018-04-01

This study presents new carbon-carbon (C/C) composite that has a density gradient within single material, and estimates its heat conduction performance by a numerical method. To address the high heat conduction of a high-density C/C, which can cause adhesion separation in the steel structures of vertical launching systems, density gradient carbon-carbon (DGCC) composite is proposed due to its exhibiting low thermal conductivity as well as excellent ablative resistance. DGCC is manufactured by hybridizing two different carbonization processes into a single carbon preform. One part exhibits a low density using phenolic resin carbonization to reduce heat conduction, and the other exhibits a high density using thermal gradient-chemical vapor infiltration for excellent ablative resistance. Numerical analysis for DGCC is performed with a heat conduction problem, and internal temperature distributions are estimated by the forward finite difference method. Material properties of the transition density layer, which is inevitably formed during DGCC manufacturing, are assumed to a combination of two density layers for numerical analysis. By comparing numerical results with experimental data, we validate that DGCC exhibits a low thermal conductivity, and it can serve as highly effective ablative material for vertical launching systems.

The relation between high-density and very-high-density amorphous ice.

PubMed

Loerting, Thomas; Salzmann, Christoph G; Winkel, Katrin; Mayer, Erwin

2006-06-28

The exact nature of the relationship between high-density (HDA) and very-high-density (VHDA) amorphous ice is unknown at present. Here we review the relation between HDA and VHDA, concentrating on experimental aspects and discuss these with respect to the relation between low-density amorphous ice (LDA) and HDA. On compressing LDA at 125 K up to 1.5 GPa, two distinct density steps are observable in the pressure-density curves which correspond to the LDA --> HDA and HDA --> VHDA conversion. This stepwise formation process LDA --> HDA --> VHDA at 125 K is the first unambiguous observation of a stepwise amorphous-amorphous-amorphous transformation sequence. Density values of amorphous ice obtained in situ between 0.3 and 1.9 GPa on isobaric heating up to the temperatures of crystallization show a pronounced change of slope at ca. 0.8 GPa which could indicate formation of a distinct phase. We infer that the relation between HDA and VHDA is very similar to that between LDA and HDA except for a higher activation barrier between the former. We further discuss the two options of thermodynamic phase transition versus kinetic densification for the HDA --> VHDA conversion.

[Dietary patterns in college freshmen and its relation to bone mineral density].

PubMed

Wang, Sufang; Mu, Min; Zhao, Yan; Wang, Xiaoqin; Shu, Long; Li, Qingyan; Li, Yingchun

2012-07-01

In order to investigate the bone density of freshmen, and to analyze the association between dietary pattern and bone mineral density (BMD). A questionnaire survey on the situation of dietary pattern was conducted in 1414 freshmen. Effective dietary survey questionnaires and bone mineral density measurements were completed for 1319 participants. Bone mass was assessed by using an Ultrasound Bone Densitometer on the right calcaneus (CM-200, Furuno Electric Corporation, Japan), and the speed of sound (SOS, m/s) was used as an indicator for bone density. Factor analysis with varimax rotation was used to identify the dietary patterns. After adjusting for confounders, covariance with Bonferroni's was used to further examine the associations between dietary patterns and bone mineral density (BMD). (1) Four major dietary patterns were noticed. Western food pattern (high consumption in hamburger, fried food, nuts, biscuit, chocolate, cola, coffee, sugars). Animal protein pattern (high consumption in pork, mutton, beef, poultry meat, animal liver). Calcium pattern (high consumption in fresh fruits, eggs, fish and shrimps, kelp laver and sea fish, milk and dairy products, beans and bean products). Traditional Chinese pattern (high consumption in rice and grain, fresh fruits, fresh vegetables, pork). (2) No association was observed between the western food pattern and bone mineral density. High animal protein pattern showed lower SOS value compared with low animal protein pattern. High calcium pattern showed higher SOS value compared with low calcium pattern. High traditional Chinese pattern showed higher SOS value compared with the low traditional Chinese pattern. Dietary patterns are closely related with bone mineral density (BMD) of freshmen.

Device and method for relativistic electron beam heating of a high-density plasma to drive fast liners

DOEpatents

Thode, Lester E.

1981-01-01

A device and method for relativistic electron beam heating of a high-density plasma in a small localized region. A relativistic electron beam generator or accelerator produces a high-voltage electron beam which propagates along a vacuum drift tube and is modulated to initiate electron bunching within the beam. The beam is then directed through a low-density gas chamber which provides isolation between the vacuum modulator and the relativistic electron beam target. The relativistic beam is then applied to a high-density target plasma which typically comprises DT, DD, hydrogen boron or similar thermonuclear gas at a density of 10.sup.17 to 10.sup.20 electrons per cubic centimeter. The target gas is ionized prior to application of the electron beam by means of a laser or other preionization source to form a plasma. Utilizing a relativistic electron beam with an individual particle energy exceeding 3 MeV, classical scattering by relativistic electrons passing through isolation foils is negligible. As a result, relativistic streaming instabilities are initiated within the high-density target plasma causing the relativistic electron beam to efficiently deposit its energy and momentum into a small localized region of the high-density plasma target. Fast liners disposed in the high-density target plasma are explosively or ablatively driven to implosion by a heated annular plasma surrounding the fast liner which is generated by an annular relativistic electron beam. An azimuthal magnetic field produced by axial current flow in the annular plasma, causes the energy in the heated annular plasma to converge on the fast liner.

Exploration of peripapillary vessel density in highly myopic eyes with peripapillary intrachoroidal cavitation and its relationship with ocular parameters using optical coherence tomography angiography.

PubMed

Chen, Qiuying; He, Jiangnan; Hua, Yihong; Fan, Ying

2017-12-01

Identifying changes of peripapillary vessel density in highly myopic eyes with peripapillary intrachoroidal cavitation by optical coherence tomography angiography. To investigate peripapillary vessel density and its relationship with other ocular parameters in highly myopic eyes with peripapillary intrachoroidal cavitation. Hospital-based, cross-sectional study. Thirty-five highly myopic eyes with peripapillary intrachoroidal cavitation, 46 highly myopic eyes without peripapillary intrachoroidal cavitation and 36 normal eyes were included in this study. All participants underwent optical coherence tomography angiography to image the retinal vasculature in the peripapillary areas, including the radial peripapillary capillaries and optic nerve head layer. Correlations between vessel density and ocular metrics were analysed. Peripapillary vessel density. In highly myopic eyes, vessel density was significantly lower in eyes with peripapillary intrachoroidal cavitation than in those without in peripapillary (P = 0.014, P = 0.037), inferotemporal (P < 0.001, P < 0.001) and superotemporal (P = 0.014, P = 0.009) areas. In the radial peripapillary capillaries layer, vessel density was negatively correlated with peripapillary atrophy area (P = 0.012) and myopic maculopathy (P = 0.002), and in the optic nerve head layer, it was negatively associated with a diagnosis of peripapillary intrachoroidal cavitation (P = 0.012) and myopic maculopathy (P < 0.001). In addition, it was positively correlated with retinal nerve fibre layer thickness in both layers (P < 0.001). Highly myopic eyes with peripapillary intrachoroidal cavitation had lower peripapillary vessel densities, especially in the temporal area, than those without. © 2017 Royal Australian and New Zealand College of Ophthalmologists.

Habitual Diet and Avocado Trial

ClinicalTrials.gov

2018-06-19

Intra-abdominal Fat; Metabolic Syndrome; High Cholesterol; Triglycerides High; Diet Habit; High Blood Sugar; Liver Fat; Dietary Modification; HDL Cholesterol, Low Serum; Cardiovascular Diseases; High Density Lipoprotein Deficiency; Low-density-lipoprotein-type; Cardiovascular Risk Factor; Diabetes

TIME-DEPENDENT DENSITY DIAGNOSTICS OF SOLAR FLARE PLASMAS USING SDO/EVE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Milligan, Ryan O.; Kennedy, Michael B.; Mathioudakis, Mihalis

2012-08-10

Temporally resolved electron density measurements of solar flare plasmas are presented using data from the EUV Variability Experiment (EVE) on board the Solar Dynamics Observatory. The EVE spectral range contains emission lines formed between 10{sup 4} and 10{sup 7} K, including transitions from highly ionized iron ({approx}>10 MK). Using three density-sensitive Fe XXI ratios, peak electron densities of 10{sup 11.2}-10{sup 12.1} cm{sup -3} were found during four X-class flares. While previous measurements of densities at such high temperatures were made at only one point during a flaring event, EVE now allows the temporal evolution of these high-temperature densities to bemore » determined at 10 s cadence. A comparison with GOES data revealed that the peak of the density time profiles for each line ratio correlated well with that of the emission measure time profile for each of the events studied.« less

High Efficiency, High Density Terrestrial Panel. [for solar cell modules

NASA Technical Reports Server (NTRS)

Wohlgemuth, J.; Wihl, M.; Rosenfield, T.

1979-01-01

Terrestrial panels were fabricated using rectangular cells. Packing densities in excess of 90% with panel conversion efficiencies greater than 13% were obtained. Higher density panels can be produced on a cost competitive basis with the standard salami panels.

High energy density electrochemical cell

NASA Technical Reports Server (NTRS)

Byrne, J. J.; Williams, D. L.

1970-01-01

Primary cell has an anode of lithium, a cathode containing dihaloisocyanuric acid, and a nonaqueous electrolyte comprised of a solution of lithium perchlorate in methyl formate. It produces an energy density of 213 watt hrs/lb and can achieve a high current density.

The onset of stress response in rainbow trout Oncorhynchus mykiss embryos subjected to density and handling.

PubMed

Ghaedi, Gholamreza; Falahatkar, Bahram; Yavari, Vahid; Sheibani, Mohammad T; Broujeni, Gholamreza Nikbakht

2015-04-01

The present study made an attempt to measure the cortisol content, as an indicator of stress response, in rainbow trout embryos which were exposed to different densities and handling stress (air exposure) during incubation. The three densities of experimental embryos at early development stages were considered as 2.55 embryos/cm(2) (low density), 5.10 embryos/cm(2) (normal density) and 7.65 embryos/cm(2) (high density). The cortisol content of eggs (5.09 ± 0.12 ng/g) decreased to 3.68 ± 0.14 ng/g in newly fertilized eggs. Resting level of cortisol dropped at three densities by day 18 of post fertilization. Then, cortisol increased at hatching stage to 1.16 ± 0.11, 1.20 ± 0.12 and 1.21 ± 0.14 ng/g at low, normal and high densities, respectively. There were no statistically significant differences between cortisol concentrations in three densities. The acute handling stress test (5-min out-of-water), conducted on embryos (48 h post fertilization, organogenesis and eyed stage) in three densities, revealed no differences in whole-body cortisol levels between stressed and unstressed experimental groups. At hatching stage in low-density group, level of cortisol increased but the difference with the pre-stress levels was not statistically significant. Furthermore, significant differences in cortisol levels of stressed and unstressed embryos were detected on hatching in normal and high density groups [1.20 ± 0.12 at time 0-1.49 ± 0.11 ng/g at 1 hps (hours post stress) and from 1.21 ± 0.14 at time 0 to 1.53 ± 0.10 ng/g at 3 hps, respectively]. The results showed no difference in profile of cortisol in different densities, but acute stress conducted on embryos, incubated in different densities, revealed differences in cortisol stress response at hatching between normal and high density, which lead to cortisol increase at hatching time. It indicates that the lag time in the cortisol response to stressors immediately after hatching does not occur when the siblings were stressed during the embryo stage. Results, finally, indicated that hypothalamus-pituitary-interrenal axis was active and responded to an acute stressor under normal and high density, but it is unresponsive to a stressor around hatching under low density.

A high-performance supercapacitor electrode based on N-doped porous graphene

NASA Astrophysics Data System (ADS)

Dai, Shuge; Liu, Zhen; Zhao, Bote; Zeng, Jianhuang; Hu, Hao; Zhang, Qiaobao; Chen, Dongchang; Qu, Chong; Dang, Dai; Liu, Meilin

2018-05-01

The development of high-performance supercapacitors (SCs) often faces some contradictory and competing requirements such as excellent rate capability, long cycling life, and high energy density. One effective strategy is to explore electrode materials of high capacitance, electrode architectures of fast charge and mass transfer, and electrolytes of wide voltage window. Here we report a facile and readily scalable strategy to produce high-performance N-doped graphene with a high specific capacitance (∼390 F g-1). A symmetric SC device with a wide voltage window of 3.5 V is also successfully fabricated based on the N-doped graphene electrode. More importantly, the as-assembled symmetric SC delivers a high energy density of 55 Wh kg-1 at a power density of 1800 W kg-1 while maintaining superior cycling life (retaining 96.6% of the initial capacitance after 20,000 cycles). Even at a power density as high as 8800 W kg-1, it still retains an energy density of 29 Wh kg-1, higher than those of previously reported graphene-based symmetric SCs.

Physical conditions in molecular clouds

NASA Technical Reports Server (NTRS)

Evans, Neal J., II

1989-01-01

Recent developments have complicated the picture of the physical conditions in molecular clouds. The discoveries of widespread emission from high-J lines of CD and 12-micron IRAS emission have revealed the presence of considerably hotter gas and dust near the surfaces of molecular clouds. These components can complicate interpretation of the bulk of the cloud gas. Commonly assumed relations between column density or mean density and cloud size are called into question by conflicting results and by consideration of selection effects. Analysis of density and density structure through molecular excitation has shown that very high densities exist in star formation regions, but unresolved structure and possible chemical effects complicate the interpretation. High resolution far-IR and submillimeter observations offer a complementary approach and are beginning to test theoretical predictions of density gradients in clouds.

An analytic model for limiting high density LH transition by the onset of the tertiary instability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singh, Raghvendra, E-mail: rsingh129@gmail.com; Jhang, Hogun; Kaang, Helen H.

2016-07-15

We perform an analytic study of the tertiary instability driven by a strong excitation of zonal flows during high density low to high (LH) mode transition. The drift resistive ballooning mode is assumed to be a dominant edge turbulence driver. The analysis reproduces main qualitative features of early computational results [Rogers and Drake, Phys. Rev. Lett. 81, 4396 (1998); Guzdar et al., Phys. Plasmas 14, 020701 (2007)], as well as new characteristics of the maximum edge density due to the onset of the tertiary instability. An analytical scaling indicates that the density scaling of LH transition power may be determinedmore » by the onset condition of the tertiary instability when the operating density approaches to the Greenwald density.« less

Alternative reproductive tactics and inverse size-assortment in a high-density fish spawning aggregation.

PubMed

Karkarey, Rucha; Zambre, Amod; Isvaran, Kavita; Arthur, Rohan

2017-02-28

At high densities, terrestrial and marine species often employ alternate reproductive tactics (ARTs) to maximize reproductive benefits. We describe ARTs in a high-density and unfished spawning aggregation of the squaretail grouper (Plectropomus areolatus) in Lakshadweep, India. As previously reported for this species, territorial males engage in pair-courtship, which is associated with a pair-spawning tactic. Here, we document a previously unreported school-courtship tactic; where territorial males court multiple females in mid-water schools, which appears to culminate in a unique 'school-spawning' tactic. Courtship tactics were conditional on body size, local mate density and habitat, likely associated with changing trade-offs between potential mating opportunities and intra-sexual competition. Counter-intuitively, the aggregation showed a habitat-specific inverse size-assortment: large males courted small females on the reef slope while small males courted equal-sized or larger females on the shelf. These patterns remained stable across two years of observation at high, unfished densities. These unique density-dependent behaviours may disappear from this aggregation as overall densities decline due to increasing commercial fishing pressure, with potentially large consequences for demographics and fitness.

Relations between sinkhole density and anthropogenic contaminants in selected carbonate aquifers in the eastern United States

USGS Publications Warehouse

Lindsey, Bruce D.; Katz, Brian G.; Berndt, Marian P.; Ardis, Ann F.; Skach, Kenneth A.

2009-01-01

The relation between sinkhole density and water quality was investigated in seven selected carbonate aquifers in the eastern United States. Sinkhole density for these aquifers was grouped into high (>25 sinkholes/100 km2), medium (1–25 sinkholes/100 km2), or low (2) categories using a geographical information system that included four independent databases covering parts of Alabama, Florida, Missouri, Pennsylvania, and Tennessee. Field measurements and concentrations of major ions, nitrate, and selected pesticides in samples from 451 wells and 70 springs were included in the water-quality database. Data were collected as a part of the US Geological Survey (USGS) National Water-Quality Assessment (NAWQA) Program. Areas with high and medium sinkhole density had the greatest well depths and depths to water, the lowest concentrations of total dissolved solids and bicarbonate, the highest concentrations of dissolved oxygen, and the lowest partial pressure of CO2 compared to areas with low sinkhole density. These chemical indicators are consistent conceptually with a conduit-flow-dominated system in areas with a high density of sinkholes and a diffuse-flow-dominated system in areas with a low density of sinkholes. Higher cave density and spring discharge in Pennsylvania also support the concept that the high sinkhole density areas are dominated by conduit-flow systems. Concentrations of nitrate-N were significantly higher (p < 0.05) in areas with high and medium sinkhole density than in low sinkhole-density areas; when accounting for the variations in land use near the sampling sites, the high sinkhole-density area still had higher concentrations of nitrate-N than the low sinkhole-density area. Detection frequencies of atrazine, simazine, metolachlor, prometon, and the atrazine degradate deethylatrazine indicated a pattern similar to nitrate; highest pesticide detections were associated with high sinkhole-density areas. These patterns generally persisted when analyzing the detection frequency by land-use groups, particularly for agricultural land-use areas where pesticide use would be expected to be higher and more uniform areally compared to urban and forested areas. Although areas with agricultural land use and a high sinkhole density were most vulnerable (median nitrate-N concentration was 3.7 mg/L, 11% of samples exceeded 10 mg/L, and had the highest frequencies of pesticide detection), areas with agricultural land use and low sinkhole density still were vulnerable to contamination (median nitrate-N concentration was 1.5 mg/L, 8% of samples exceeded 10 mg/L, and had some of the highest frequencies of detections of pesticides). This may be due in part to incomplete or missing data regarding karst features (such as buried sinkholes, low-permeability material in bottom of sinkholes) that do not show up at the scales used for regional mapping and to inconsistent methods among states in karst feature delineation.

Nanostructured Electrode Materials Derived from Metal-Organic Framework Xerogels for High-Energy-Density Asymmetric Supercapacitor.

PubMed

Mahmood, Asif; Zou, Ruqiang; Wang, Qingfei; Xia, Wei; Tabassum, Hassina; Qiu, Bin; Zhao, Ruo

2016-01-27

This work successfully demonstrates metal-organic framework (MOF) derived strategy to prepare nanoporous carbon (NPC) with or without Fe3O4/Fe nanoparticles by the optimization of calcination temperature as highly active electrode materials for asymmetric supercapacitors (ASC). The nanostructured Fe3O4/Fe/C hybrid shows high specific capacitance of 600 F/g at a current density of 1 A/g and excellent capacitance retention up to 500 F/g at 8 A/g. Furthermore, hierarchically NPC with high surface area also obtained from MOF gels displays excellent electrochemical performance of 272 F/g at 2 mV/s. Considering practical applications, aqueous ASC (aASC) was also assembled, which shows high energy density of 17.496 Wh/kg at the power density of 388.8 W/kg. The high energy density and excellent capacity retention of the developed materials show great promise for the practical utilization of these energy storage devices.

High population density of black-handed spider monkeys (Ateles geoffroyi) in Costa Rican lowland wet forest.

PubMed

Weghorst, Jennifer A

2007-04-01

The main objective of this study was to estimate the population density and demographic structure of spider monkeys living in wet forest in the vicinity of Sirena Biological Station, Corcovado National Park, Costa Rica. Results of a 14-month line-transect survey showed that spider monkeys of Sirena have one of the highest population densities ever recorded for this genus. Density estimates varied, however, depending on the method chosen to estimate transect width. Data from behavioral monitoring were available to compare density estimates derived from the survey, providing a check of the survey's accuracy. A combination of factors has most probably contributed to the high density of Ateles, including habitat protection within a national park and high diversity of trees of the fig family, Moraceae. Although natural densities of spider monkeys at Sirena are substantially higher than those recorded at most other sites and in previous studies at this site, mean subgroup size and age ratios were similar to those determined in previous studies. Sex ratios were similar to those of other sites with high productivity. Although high densities of preferred fruit trees in the wet, productive forests of Sirena may support a dense population of spider monkeys, other demographic traits recorded at Sirena fall well within the range of values recorded elsewhere for the species.

Departure mechanisms for host search on high-density patches by the Meteorus pulchricornis.

PubMed

Sheng, Sheng; Feng, Sufang; Meng, Ling; Li, Baoping

2014-01-01

Less attention has been paid to the parasitoid-host system in which the host occurs in considerably high density with a hierarchical patch structure in studies on time allocation strategies of parasitoids. This study used the parasitoid Meteorus pulchricornis (Wesmael) (Hymenoptera: Braconidae) and the Oriental leafworm, Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae) as the parasitoids-host model system to investigate patch-leaving mechanisms as affected by the high-host density, hierarchical patch structure, and foraging behaviors on both former and current patches. The results showed that three out of eight covariates tested had significant effects on the patch-leaving tendency, including the host density, ovipositor insertion, and host rejection on the current patch. The parasitoid paid more visits to the patch with high-density hosts. While the patch with higher host densities decreased the leaving tendency, the spatial distribution of hosts examined had no effect on the leaving tendency. Both oviposition and host rejection decreased the patch-leaving tendency. The variables associated with the former patch, such as the host density and number of ovipositor insertions, however, did not have an effect on the leaving tendency. Our study suggested that M. pulchricornis females may use an incremental mechanism to exploit high-density patches to the fullest. © The Author 2014. Published by Oxford University Press on behalf of the Entomological Society of America.

Effect of stocking density on performances of juvenile turbot ( Scophthalmus maximus) in recirculating aquaculture systems

NASA Astrophysics Data System (ADS)

Li, Xian; Liu, Ying; Blancheton, Jean-Paul

2013-05-01

Limited information has been available about the influence of loading density on the performances of Scophthalmus maximus, especially in recirculating aquaculture systems (RAS). In this study, turbot (13.84±2.74 g; average weight±SD) were reared at four different initial densities (low 0.66, medium 1.26, sub-high 2.56, high 4.00 kg/m2) for 10 weeks in RAS at 23±1°C. Final densities were 4.67, 7.25, 14.16, and 17.47 kg/m2, respectively, which translate to 82, 108, 214, and 282 percent coverage of the tank bottom. Density had both negative and independent impacts on growth. The final mean weight, specific growth rate (SGR), and voluntary feed intake significantly decreased and the coefficient of variation (CV) of final body weight increased with increase in stocking density. The medium and sub-high density groups did not differ significantly in SGR, mean weight, CV, food conversion rate (FCR), feed intake, blood parameters, and digestive enzymes. The protease activities of the digestive tract at pH 7, 8.5, 9, and 10 were significantly higher for the highest density group, but tended to be lower (not significantly) at pH 4 and 8.5 for the lowest density group. The intensity of protease activity was inversely related to feed intake at the different densities. Catalase activity was higher (but not significantly) at the highest density, perhaps because high density started to induce an oxidative effect in turbot. In conclusion, turbot can be cultured in RAS at a density of less than 17.47 kg/m2. With good water quality and no feed limitation, initial density between 1.26 and 2.56 kg/m2 (final: 7.25 and 14.16 kg/m2) would not negatively affect the turbot cultured in RAS. For culture at higher density, multi-level feeding devices are suggested to ease feeding competition.

TEMPO-based catholyte for high-energy density nonaqueous redox flow batteries.

PubMed

Wei, Xiaoliang; Xu, Wu; Vijayakumar, Murugesan; Cosimbescu, Lelia; Liu, Tianbiao; Sprenkle, Vincent; Wang, Wei

2014-12-03

A TEMPO-based non-aqueous electrolyte with the TEMPO concentration as high as 2.0 m is demonstrated as a high-energy-density catholyte for redox flow battery applications. With a hybrid anode, Li|TEMPO flow cells using this electrolyte deliver an energy efficiency of ca. 70% and an impressively high energy density of 126 W h L(-1) . © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Radiation source

DOEpatents

Thode, Lester E.

1981-01-01

A device and method for relativistic electron beam heating of a high-density plasma in a small localized region. A relativistic electron beam generator or accelerator produces a high-voltage electron beam which propagates along a vacuum drift tube and is modulated to initiate electron bunching within the beam. The beam is then directed through a low-density gas chamber which provides isolation between the vacuum modulator and the relativistic electron beam target. The relativistic beam is then applied to a high-density target plasma which typically comprises DT, DD, or similar thermonuclear gas at a density of 10.sup.17 to 10.sup.20 electrons per cubic centimeter. The target gas is ionized prior to application of the relativistic electron beam by means of a laser or other preionization source to form a plasma. Utilizing a relativistic electron beam with an individual particle energy exceeding 3 MeV, classical scattering by relativistic electrons passing through isolation foils is negligible. As a result, relativistic streaming instabilities are initiated within the high-density target plasma causing the relativistic electron beam to efficiently deposit its energy into a small localized region of the high-density plasma target.

High density diffusion-free nanowell arrays.

PubMed

Takulapalli, Bharath R; Qiu, Ji; Magee, D Mitchell; Kahn, Peter; Brunner, Al; Barker, Kristi; Means, Steven; Miersch, Shane; Bian, Xiaofang; Mendoza, Alex; Festa, Fernanda; Syal, Karan; Park, Jin G; LaBaer, Joshua; Wiktor, Peter

2012-08-03

Proteomics aspires to elucidate the functions of all proteins. Protein microarrays provide an important step by enabling high-throughput studies of displayed proteins. However, many functional assays of proteins include untethered intermediates or products, which could frustrate the use of planar arrays at very high densities because of diffusion to neighboring features. The nucleic acid programmable protein array (NAPPA) is a robust in situ synthesis method for producing functional proteins just-in-time, which includes steps with diffusible intermediates. We determined that diffusion of expressed proteins led to cross-binding at neighboring spots at very high densities with reduced interspot spacing. To address this limitation, we have developed an innovative platform using photolithographically etched discrete silicon nanowells and used NAPPA as a test case. This arrested protein diffusion and cross-binding. We present confined high density protein expression and display, as well as functional protein-protein interactions, in 8000 nanowell arrays. This is the highest density of individual proteins in nanovessels demonstrated on a single slide. We further present proof of principle results on ultrahigh density protein arrays capable of up to 24000 nanowells on a single slide.

The Google High Power Density Inverter Prize: Innovation in PV Inverter Power Density: Cooperative Research and Development Final Report, CRADA Number: CRD-14-568

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lundstrom, Blake

Google is encouraging development of advanced photovoltaic inverters with high power density by holding a public competition and offering a prize for the best performing high power developed. NREL will perform the performance and validation for all inverters entered into the competition and provide results to Google.

77 FR 27819 - Self-Regulatory Organizations; NASDAQ OMX PHLX LLC; Notice of Filing and Immediate Effectiveness...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-11

... Change To Modify the Pricing Schedule Regarding the Co-Location Super High Density Cabinet Monthly Fee... super high-density cabinet monthly fee. The Exchange will implement the proposed change on May 1, 2012... Schedule at Section X(a) to reduce the co-location super high-density cabinet on-going monthly fee from $15...

77 FR 28414 - Self-Regulatory Organizations; NASDAQ OMX BX, Inc.; Notice of Filing and Immediate Effectiveness...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-14

... Modify the Exchange's Co-Location Super High Density Cabinet Monthly Fee May 8, 2012. Pursuant to Section... Change The Exchange proposes to modify the Exchange's co-location super high-density cabinet monthly fee... modifying Rule 7034(a) by reducing its co-location super high-density cabinet on-going monthly fee from $15...

Insights Into Upland Cotton (Gossypium hirsutum L.) Genetic Recombination Based on 3 High-Density Single-Nucleotide Polymorphism and a Consensus Map Developed Independently With Common Parents. Genomics Insights

USDA-ARS?s Scientific Manuscript database

High-density linkage maps are vital to supporting the correct placement of scaffolds and gene sequences on chromosomes and fundamental to contemporary organismal research and scientific approaches to genetic improvement; high-density linkage maps are especially important in paleopolyploids with exce...

High-Density Near-Field Readout over 50 GB Capacity Using Solid Immersion Lens with High Refractive Index

NASA Astrophysics Data System (ADS)

Shinoda, Masataka; Saito, Kimihiro; Kondo, Takao; Ishimoto, Tsutomu; Nakaoki, Ariyoshi

2003-02-01

We have investigated high-density near-field readout using a solid immersion lens with a high refractive index. By using a glass material with a high refractive index of 2.08, we developed an optical pick-up with the effective numerical aperture of 1.8. We could observe a clear eye pattern for a 50 GB capacity disc in 120 mm diameter. We confirmed that the near-field readout system is promising method of realizing a high-density optical disc system.

Ambipolar zinc-polyiodide electrolyte for a high-energy density aqueous redox flow battery

DOE PAGES

Li, Bin; Nie, Zimin; Vijayakumar, M.; ...

2015-02-24

Large-scale energy storage systems are crucial for substantial deployment of renewable energy sources. Energy storage systems with high energy density, high safety, and low cost and environmental friendliness are desired. To overcome the major limitations of the current aqueous redox flow battery systems, namely lower energy density (~25 Wh L -1) and presence of strong acids and/or other hazardous, a high energy density aqueous zinc/polyiodide flow battery (ZIB) is designed with near neutral ZnI 2 solutions as catholytes. The energy density of ZIB could reach 322 Wh L -1 at the solubility limit of ZnI 2 in water (~7 M).more » We demonstrate charge and discharge energy densities of 245.9 Wh/L and 166.7 Wh L-1 with ZnI 2 electrolyte at 5.0 M, respectively. The addition of ethanol (EtOH) in ZnI 2 electrolyte can effectively mitigate the growth of zinc dendrite at the anode and improve the stability of catholytes with wider temperature window (-20 to 50°C), which enable ZIB system to be a promising alternative as a high-energy and high- safety stationary energy storage system.« less

Characterization of the high density plasma etching process of CCTO thin films for the fabrication of very high density capacitors

NASA Astrophysics Data System (ADS)

Altamore, C.; Tringali, C.; Sparta', N.; Di Marco, S.; Grasso, A.; Ravesi, S.

2010-02-01

In this work the feasibility of CCTO (Calcium Copper Titanate) patterning by etching process is demonstrated and fully characterized in a hard to etch materials etcher. CCTO sintered in powder shows a giant relative dielectric constant (105) measured at 1 MHz at room temperature. This feature is furthermore coupled with stability from 101 Hz to 106 Hz in a wide temperature range (100K - 600K). In principle, this property can allow to fabricate very high capacitance density condenser. Due to its perovskite multi-component structure, CCTO can be considered a hard to etch material. For high density capacitor fabrication, CCTO anisotropic etching is requested by using high density plasma. The behavior of etched CCTO was studied in a HRe- (High Density Reflected electron) plasma etcher using Cl2/Ar chemistry. The relationship between the etch rate and the Cl2/Ar ratio was also studied. The effects of RF MHz, KHz Power and pressure variation, the impact of HBr addiction to the Cl2/Ar chemistry on the CCTO etch rate and on its selectivity to Pt and photo resist was investigated.

High Density Diffusion-Free Nanowell Arrays

PubMed Central

Takulapalli, Bharath R; Qiu, Ji; Magee, D. Mitchell; Kahn, Peter; Brunner, Al; Barker, Kristi; Means, Steven; Miersch, Shane; Bian, Xiaofang; Mendoza, Alex; Festa, Fernanda; Syal, Karan; Park, Jin; LaBaer, Joshua; Wiktor, Peter

2012-01-01

Proteomics aspires to elucidate the functions of all proteins. Protein microarrays provide an important step by enabling high-throughput studies of displayed proteins. However, many functional assays of proteins include untethered intermediates or products, which could frustrate the use of planar arrays at very high densities because of diffusion to neighboring features. The nucleic acid programmable protein array (NAPPA), is a robust, in situ synthesis method for producing functional proteins just-in-time, which includes steps with diffusible intermediates. We determined that diffusion of expressed proteins led to cross-binding at neighboring spots at very high densities with reduced inter-spot spacing. To address this limitation, we have developed an innovative platform using photolithographically-etched discrete silicon nanowells and used NAPPA as a test case. This arrested protein diffusion and cross-binding. We present confined high density protein expression and display, as well as functional protein-protein interactions, in 8,000 nanowell arrays. This is the highest density of individual proteins in nano-vessels demonstrated on a single slide. We further present proof of principle results on ultra-high density protein arrays capable of up to 24,000 nanowells on a single slide. PMID:22742968

The effects of oil-in-water nanoemulsion polyethylene glycol surface density on intracellular stability, pharmacokinetics, and biodistribution in tumor bearing mice.

PubMed

Hak, Sjoerd; Garaiova, Zuzana; Olsen, Linda Therese; Nilsen, Asbjørn Magne; de Lange Davies, Catharina

2015-04-01

Lipid-based nanoparticles are extensively studied for drug delivery. These nanoparticles are often surface-coated with polyethylene glycol (PEG) to improve their biodistribution. Until now, the effects of varying PEG surface density have been studied in a narrow and low range. Here, the effects of high and a broad range of PEG surface densities on the in vivo performance of lipid-based nanoparticles were studied. Oil-in-water nanoemulsions were prepared with PEG surface densities of 5-50 mol%. Confocal microscopy was used to assess intracellular disintegration in vitro. In vivo pharmacokinetics and biodistribution in tumor bearing mice were studied using a small animal optical imager. PEG surface density did not affect intracellular nanoemulsion stability. Surprisingly, circulation half-lives decreased with increasing PEG surface density. A plausible explanation was that nanoemulsion with high (50 mol%) PEG surface density activated the complement in a whole blood assay, whereas nanoemulsion with low (5 mol%) PEG density did not. In vivo, nanoemulsion with low PEG surface density was mostly confined to the tumor and organs of the mononuclear phagocyte system, whereas nanoemulsion with high PEG density accumulated throughout the mouse. Optimal PEG surface density of lipid-based nanoparticles for tumor targeting was found to be below 10 mol%.

Neighbourhood walkability, road density and socio-economic status in Sydney, Australia.

PubMed

Cowie, Christine T; Ding, Ding; Rolfe, Margaret I; Mayne, Darren J; Jalaludin, Bin; Bauman, Adrian; Morgan, Geoffrey G

2016-04-27

Planning and transport agencies play a vital role in influencing the design of townscapes, travel modes and travel behaviors, which in turn impact on the walkability of neighbourhoods and residents' physical activity opportunities. Optimising neighbourhood walkability is desirable in built environments, however, the population health benefits of walkability may be offset by increased exposure to traffic related air pollution. This paper describes the spatial distribution of neighbourhood walkability and weighted road density, a marker for traffic related air pollution, in Sydney, Australia. As exposure to air pollution is related to socio-economic status in some cities, this paper also examines the spatial distribution of weighted road density and walkability by socio-economic status (SES). We calculated walkability, weighted road density (as a measure of traffic related air pollution) and SES, using predefined and validated measures, for 5858 Sydney neighbourhoods, representing 3.6 million population. We overlaid tertiles of walkability and weighted road density to define "sweet-spots" (high walkability-low weighted road density), and "sour- spots" (low walkability-high weighted road density) neighbourhoods. We also examined the distribution of walkability and weighted road density by SES quintiles. Walkability and weighted road density showed a clear east-west gradient across the region. Our study found that only 4 % of Sydney's population lived in sweet-spot" neighbourhoods with high walkability and low weighted road density (desirable), and these tended to be located closer to the city centre. A greater proportion of neighbourhoods had health limiting attributes of high weighted road density or low walkability (about 20 % each), and over 5 % of the population lived in "sour-spot" neighbourhoods with low walkability and high weighted road density (least desirable). These neighbourhoods were more distant from the city centre and scattered more widely. There were no linear trends between walkability/weighted road density and neighbourhood SES. Our walkability and weighted road density maps and associated analyses by SES can help identify neighbourhoods with inequalities in health-promoting or health-limiting environments. Planning agencies should seek out opportunities for increased neighbourhood walkability through improved urban development and transport planning, which simultaneously minimizes exposure to traffic related air pollution.

High density of tree-cavities and snags in tropical dry forest of western Mexico raises questions for a latitudinal gradient.

PubMed

Vázquez, Leopoldo; Renton, Katherine

2015-01-01

It has been suggested that a latitudinal gradient exists of a low density of snags and high density of naturally-formed tree-cavities in tropical vs. temperate forests, though few cavities may have characteristics suitable for nesting by birds. We determined snag and cavity density, characteristics, and suitability for birds in a tropical dry forest biome of western Mexico, and evaluated whether our data fits the trend of snag and cavity density typically found in tropical moist and wet forests. We established five 0.25-ha transects to survey and measure tree-cavities and snags in each of three vegetation types of deciduous, semi-deciduous, and mono-dominant Piranhea mexicana forest, comprising a total of 3.75 ha. We found a high density of 77 cavities/ha, with 37 cavities suitable for birds/ha, where density, and characteristics of cavities varied significantly among vegetation types. Lowest abundance of cavities occurred in deciduous forest, and these were in smaller trees, at a lower height, and with a narrower entrance diameter. Only 8.6% of cavities were excavated by woodpeckers, and only 11% of cavities were occupied, mainly by arthropods, though 52% of all cavities were unsuitable for birds. We also found a high density of 56 snags/ha, with greatest density in deciduous forest (70 snags/ha), though these were of significantly smaller diameter, and snags of larger diameter were more likely to contain cavities. The Chamela-Cuixmala tropical dry forest had the highest density of snags recorded for any tropical or temperate forest, and while snag density was significantly correlated with mean snag dbh, neither latitude nor mean dbh predicted snag density in ten forest sites. The high spatial aggregation of snag and cavity resources in tropical dry forest may limit their availability, particularly for large-bodied cavity adopters, and highlights the importance of habitat heterogeneity in providing resources for primary and secondary cavity-nesters.

High Density of Tree-Cavities and Snags in Tropical Dry Forest of Western Mexico Raises Questions for a Latitudinal Gradient

PubMed Central

Vázquez, Leopoldo; Renton, Katherine

2015-01-01

It has been suggested that a latitudinal gradient exists of a low density of snags and high density of naturally-formed tree-cavities in tropical vs. temperate forests, though few cavities may have characteristics suitable for nesting by birds. We determined snag and cavity density, characteristics, and suitability for birds in a tropical dry forest biome of western Mexico, and evaluated whether our data fits the trend of snag and cavity density typically found in tropical moist and wet forests. We established five 0.25-ha transects to survey and measure tree-cavities and snags in each of three vegetation types of deciduous, semi-deciduous, and mono-dominant Piranhea mexicana forest, comprising a total of 3.75 ha. We found a high density of 77 cavities/ha, with 37 cavities suitable for birds/ha, where density, and characteristics of cavities varied significantly among vegetation types. Lowest abundance of cavities occurred in deciduous forest, and these were in smaller trees, at a lower height, and with a narrower entrance diameter. Only 8.6% of cavities were excavated by woodpeckers, and only 11% of cavities were occupied, mainly by arthropods, though 52% of all cavities were unsuitable for birds. We also found a high density of 56 snags/ha, with greatest density in deciduous forest (70 snags/ha), though these were of significantly smaller diameter, and snags of larger diameter were more likely to contain cavities. The Chamela-Cuixmala tropical dry forest had the highest density of snags recorded for any tropical or temperate forest, and while snag density was significantly correlated with mean snag dbh, neither latitude nor mean dbh predicted snag density in ten forest sites. The high spatial aggregation of snag and cavity resources in tropical dry forest may limit their availability, particularly for large-bodied cavity adopters, and highlights the importance of habitat heterogeneity in providing resources for primary and secondary cavity-nesters. PMID:25615612

Dissepiments, density bands and signatures of thermal stress in Porites skeletons

NASA Astrophysics Data System (ADS)

DeCarlo, Thomas M.; Cohen, Anne L.

2017-09-01

The skeletons of many reef-building corals are accreted with rhythmic structural patterns that serve as valuable sclerochronometers. Annual high- and low-density band couplets, visible in X-radiographs or computed tomography scans, are used to construct age models for paleoclimate reconstructions and to track variability in coral growth over time. In some corals, discrete, anomalously high-density bands, called "stress bands," preserve information about coral bleaching. However, the mechanisms underlying the formation of coral skeletal density banding remain unclear. Dissepiments—thin, horizontal sheets of calcium carbonate accreted by the coral to support the living polyp—play a key role in the upward growth of the colony. Here, we first conducted a vital staining experiment to test whether dissepiments were accreted with lunar periodicity in Porites coral skeleton, as previously hypothesized. Over 6, 15, and 21 months, dissepiments consistently formed in a 1:1 ratio to the number of full moons elapsed over each study period. We measured dissepiment spacing to reconstruct multiple years of monthly skeletal extension rates in two Porites colonies from Palmyra Atoll and in another from Palau that bleached in 1998 under anomalously high sea temperatures. Spacing between successive dissepiments exhibited strong seasonality in corals containing annual density bands, with narrow (wide) spacing associated with high (low) density, respectively. A high-density "stress band" accreted during the 1998 bleaching event was associated with anomalously low dissepiment spacing and missed dissepiments, implying that thermal stress disrupts skeletal extension. Further, uranium/calcium ratios increased within stress bands, indicating a reduction in the carbonate ion concentration of the coral's calcifying fluid under stress. Our study verifies the lunar periodicity of dissepiments, provides a mechanistic basis for the formation of annual density bands in Porites, and reveals the underlying cause of high-density stress bands.

Effects of chronic high stocking density on liver proteome of rainbow trout (Oncorhynchus mykiss).

PubMed

Naderi, Mahdi; Keyvanshokooh, Saeed; Salati, Amir Parviz; Ghaedi, Alireza

2017-10-01

The main aim of the present study was to assess the effects of chronic high stocking density on liver proteome of rainbow trout. Rainbow trout juveniles (42.6 ± 2.3 g average body weight) were randomly distributed into six tanks at two stocking densities (low stocking density (LD) = 20 kg m -3 and high stocking density (HD) = 80 kg m -3 ). Both treatments were performed in triplicate tanks for a period of 60 days. High stocking density caused a reduction in the growth performance compared with LD fish. Lysozyme activity increased with stocking density, while serum complement activity presented the opposite pattern. Serum cortisol and total protein levels did not show significant differences (P > 0.05) between experimental groups. The fish reared at high stocking density showed significantly lower osmolality and globulin values but higher albumin level. The HD group had significantly higher activities of catalase, glutathione peroxidase and superoxide dismutase, and malondialdehyde content in the liver when compared to the LD group. Comparative proteomics was used to determine the proteomic responses in livers of rainbow trout reared at high stocking density for 60 days. Out of nine protein spots showing altered abundance (>1.5-folds, P < 0.05), eight spots were successfully identified. Two proteins including apolipoprotein A-I-2 precursor and mitochondrial stress-70 protein were found to increase in HD group. The spots found to decrease in the HD group were identified as follows: 2-peptidylprolyl isomerase A, two isoforms of glyceraldehydes-3-phosphate dehydrogenase, an unnamed protein product similar to fructose-bisphosphate aldolase, 78 kDa glucose-regulated protein, and serum albumin 1 protein.

Depositional History of the Western Amundsen Basin, Arctic Ocean, and Implications for Neogene Climate and Oceanographic Conditions

NASA Astrophysics Data System (ADS)

Hopper, J. R.; Castro, C. F.; Knutz, P. C.; Funck, T.

2017-12-01

Seismic reflection data collected in the western Amundsen Basin as part of the Law of the Sea program for the Kingdom of Denmark show a uniform and continuous cover of sediments over oceanic basement. An interpretation of seismic facies units shows that the depositional history of the basin reflects changing tectonic, climatic, and oceanographic conditions throughout the Cenozoic. In this contribution, the Miocene to present history is summarized. Two distinct changes in the depositional environment are proposed, first in response to the development of a deep water connection between the Arctic and North Atlantic, and the second in response to the onset of perennial sea ice cover in the Arctic. In the early to mid-Miocene, a buildup of contourite deposits indicates a distinct change in sedimentation that is particularly well developed near the flank of the Lomonosov Ridge. It is suggested that this is a response to the opening of the Fram Strait and the establishment of geostrophic bottom currents that flowed from the Laptev Sea towards Greenland. These deposits are overlain by a seismic facies unit characterized by buried channels and erosional features. These include prominent basinward levee systems that suggest a channel morphology maintained by overbank deposition of muddy sediments carried by suspension currents periodically spilling over the channel pathway. These deposits indicate a change to a much higher energy environment that is proposed to be a response to brine formation associated with the onset of perennial sea ice cover in the Arctic Ocean. This interpretation implies that the development of extensive sea ice cover results in a significant change in the energy environment of the ocean that is reflected in the depositional and erosional patterns observed. The lack of similar high energy erosional features and the presence of contourite deposits throughout most of the Miocene may indicate the Arctic Ocean was relatively ice-free until the very latest Miocene.

Status and Impacts of Arctic Freshwater Export

NASA Astrophysics Data System (ADS)

Haine, T. W. N.

2017-12-01

Large freshwater anomalies clearly exist in the Arctic Ocean. For example, liquid freshwater has accumulated in the Beaufort Gyre in the decade of the 2000s compared to 1980-2000, with an extra ≈5000 km3—about 25%—being stored. The sources of freshwater to the Arctic from precipitation and runoff have increased between these periods (most of the evidence comes from models). Despite flux increases from 2001 to 2011, it is uncertain if the marine freshwater source through Bering Strait for the 2000s has changed, as observations in the 1980s and 1990s are incomplete. The marine freshwater fluxes draining the Arctic through Fram and Davis straits are also insignificantly different. In this way, the balance of sources and sinks of freshwater to the Arctic, Canadian Arctic Archipelago (CAA), and Baffin Bay shifted to about 1200±730 km3yr-1 freshening the region, on average, during the 2000s. The observed accumulation of liquid freshwater is consistent with this increased supply and the loss of freshwater from sea ice (Figure, right). Evidence exists that such discharges can impact the Atlantic meridional overturning circulation, and hence Atlantic sector climate. Nevertheless, it appears that the observed AMOC variability since 2004, when high quality measurements began, is not attributable to anthropogenic influence. This work is based on, and updated from, Haine et al. (2015), Carmack et al. (2016), and Haine (2016). Haine, T. W. N. Ocean science: Vagaries of Atlantic overturning. Nature Geoscience, 9, 479-480, 10.1038/ngeo2748, 2016. T. W. N. Haine et al., Arctic Freshwater Export: Status, Mechanisms, and Prospects, Global Planetary Change, 125, 13-35, 10.1016/j.glopacha.2014.11.013, 2015. E. Carmack et al., Fresh water and its role in the Arctic Marine System: sources, disposition, storage, export, and physical and biogeochemical consequences in the Arctic and global oceans. J. G. Res. Biogeosciences, 10.1002/2015JG003140, 2016.

DOE Office of Scientific and Technical Information (OSTI.GOV)

N, Gwilliam M; J, Collins D; O, Leach M

Purpose: To assess the feasibility of accurately quantifying the concentration of MRI contrast agent (CA) in pulsatile flowing blood by measuring its T{sub 1}, as is common for the purposes of obtaining a patientspecific arterial input function (AIF). Dynamic contrast enhanced (DCE) - MRI and pharmacokinetic (PK) modelling is widely used to produce measures of vascular function but accurate measurement of the AIF undermines their accuracy. A proposed solution is to measure the T{sub 1} of blood in a large vessel using the Fram double flip angle method during the passage of a bolus of CA. This work expands onmore » previous work by assessing pulsatile flow and the changes in T{sub 1} seen with a CA bolus. Methods: A phantom was developed which used a physiological pump to pass fluid of a known T{sub 1} (812ms) through the centre of a head coil of a clinical 1.5T MRI scanner. Measurements were made using high temporal resolution sequences suitable for DCE-MRI and were used to validate a virtual phantom that simulated the expected errors due to pulsatile flow and bolus of CA concentration changes typically found in patients. Results: : Measured and virtual results showed similar trends, although there were differences that may be attributed to the virtual phantom not accurately simulating the spin history of the fluid before entering the imaging volume. The relationship between T{sub 1} measurement and flow speed was non-linear. T{sub 1} measurement is compromised by new spins flowing into the imaging volume, not being subject to enough excitations to have reached steady-state. The virtual phantom demonstrated a range of recorded T{sub 1} for various simulated T{sub 1} / flow rates. Conclusion: T{sub 1} measurement of flowing blood using standard DCE-MRI sequences is very challenging. Measurement error is non-linear with relation to instantaneous flow speed. Optimising sequence parameters and lowering baseline T{sub 1} of blood should be considered.« less

Automated connectionist-geostatistical classification as an approach to identify sea ice and land ice types, properties and provinces

NASA Astrophysics Data System (ADS)

Goetz-Weiss, L. R.; Herzfeld, U. C.; Trantow, T.; Hunke, E. C.; Maslanik, J. A.; Crocker, R. I.

2016-12-01

An important problem in model-data comparison is the identification of parameters that can be extracted from observational data as well as used in numerical models, which are typically based on idealized physical processes. Here, we present a suite of approaches to characterization and classification of sea ice and land ice types, properties and provinces based on several types of remote-sensing data. Applications will be given to not only illustrate the approach, but employ it in model evaluation and understanding of physical processes. (1) In a geostatistical characterization, spatial sea-ice properties in the Chukchi and Beaufort Sea and in Elsoon Lagoon are derived from analysis of RADARSAT and ERS-2 SAR data. (2) The analysis is taken further by utilizing multi-parameter feature vectors as inputs for unsupervised and supervised statistical classification, which facilitates classification of different sea-ice types. (3) Characteristic sea-ice parameters, as resultant from the classification, can then be applied in model evaluation, as demonstrated for the ridging scheme of the Los Alamos sea ice model, CICE, using high-resolution altimeter and image data collected from unmanned aircraft over Fram Strait during the Characterization of Arctic Sea Ice Experiment (CASIE). The characteristic parameters chosen in this application are directly related to deformation processes, which also underly the ridging scheme. (4) The method that is capable of the most complex classification tasks is the connectionist-geostatistical classification method. This approach has been developed to identify currently up to 18 different crevasse types in order to map progression of the surge through the complex Bering-Bagley Glacier System, Alaska, in 2011-2014. The analysis utilizes airborne altimeter data and video image data and satellite image data. Results of the crevasse classification are compare to fracture modeling and found to match.

Comparison of dual-energy X-ray absorptiometry and magnetic resonance imaging-measured adipose tissue depots in HIV-infected and control subjects.

PubMed

Scherzer, Rebecca; Shen, Wei; Bacchetti, Peter; Kotler, Donald; Lewis, Cora E; Shlipak, Michael G; Punyanitya, Mark; Heymsfield, Steven B; Grunfeld, Carl

2008-10-01

Studies in persons without HIV infection have compared adipose tissue measured by dual-energy X-ray absorptiometry (DXA) and magnetic resonance imaging (MRI), but no such study has been conducted in HIV-infected (HIV+) subjects, who have a high prevalence of regional fat loss. We compared DXA- with MRI-measured trunk, leg, arm, and total fat in HIV+ and control subjects. A cross-sectional analysis was conducted in 877 HIV+ subjects and 260 control subjects in FRAM (Study of Fat Redistribution and Metabolic Change in HIV Infection), stratified by sex and HIV status. Univariate associations of DXA with MRI were strongest for total and trunk fat (r > or = 0.92) and slightly weaker for leg (r > or = 0.87) and arm (r > or = 0.71) fat. The average estimated limb fat was substantially greater for DXA than for MRI for HIV+ and control men and women (all P < 0.0001). Less of a difference was observed in trunk fat measured by DXA and MRI, but the difference was still statistically significant (P < 0.0001). Bland-Altman plots showed increasing differences and variability. Greater average limb fat in control and HIV+ subjects (both P < 0.0001) was associated with greater differences between DXA and MRI measurements. Because the control subjects had more limb fat than did the HIV+ subjects, greater amounts of fat were measured by DXA than by MRI when control subjects were compared with HIV+ subjects. More HIV+ subjects had leg fat in the bottom decile of the control subjects by DXA than by MRI (P < 0.0001). Although DXA- and MRI-measured adipose tissue depots correlate strongly in HIV+ and control subjects, differences increase as average fat increases, particularly for limb fat. DXA may estimate a higher prevalence of peripheral lipoatrophy than does MRI in HIV+ subjects.

Superior performance asymmetric supercapacitors based on a directly grown commercial mass 3D Co3O4@Ni(OH)2 core-shell electrode.

PubMed

Tang, Chun-hua; Yin, Xuesong; Gong, Hao

2013-11-13

Pseudocapacitors based on fast surface Faradaic reactions can achieve high energy densities together with high power densities. Usually, researchers develop a thin layer of active materials to increase the energy density by enhancing the surface area; meanwhile, this sacrifices the mass loading. In this work, we developed a novel 3D core-shell Co3O4@Ni(OH)2 electrode that can provide high energy density with very high mass loading. Core-shell porous nanowires (Co3O4@Ni(OH)2) were directly grown on a Ni current collector as an integrated electrode/collector for the supercapacitor anode. This Co3O4@Ni(OH)2 core-shell nanoarchitectured electrode exhibits an ultrahigh areal capacitance of 15.83 F cm(-2). The asymmetric supercapacitor prototypes, assembled using Co3O4@Ni(OH)2 as the anode, reduced graphene oxide (RGO) or active carbon (AC) as the cathode, and 6 M aqueous KOH as the electrolyte, exhibit very high energy densities falling into the energy-density range of Li-ion batteries. Because of the large mass loading and high energy density, the prototypes can drive a minifan or light a bulb even though the size is very small. These results indicate that our asymmetric supercapacitors have outstanding potential in commercial applications. Systematic study and scientific understanding were carried out.

Fluorescent Fe K Emission from High Density Accretion Disks

NASA Astrophysics Data System (ADS)

Bautista, Manuel; Mendoza, Claudio; Garcia, Javier; Kallman, Timothy R.; Palmeri, Patrick; Deprince, Jerome; Quinet, Pascal

2018-06-01

Iron K-shell lines emitted by gas closely orbiting black holes are observed to be grossly broadened and skewed by Doppler effects and gravitational redshift. Accordingly, models for line profiles are widely used to measure the spin (i.e., the angular momentum) of astrophysical black holes. The accuracy of these spin estimates is called into question because fitting the data requires very high iron abundances, several times the solar value. Meanwhile, no plausible physical explanation has been proffered for why these black hole systems should be so iron rich. The most likely explanation for the super-solar iron abundances is a deficiency in the models, and the leading candidate cause is that current models are inapplicable at densities above 1018 cm-3. We study the effects of high densities on the atomic parameters and on the spectral models for iron ions. At high densities, Debye plasma can affect the effective atomic potential of the ions, leading to observable changes in energy levels and atomic rates with respect to the low density case. High densities also have the effec of lowering energy the atomic continuum and reducing the recombination rate coefficients. On the spectral modeling side, high densities drive level populations toward a Boltzman distribution and very large numbers of excited atomic levels, typically accounted for in theoretical spectral models, may contribute to the K-shell spectrum.

Series asymmetric supercapacitors based on free-standing inner-connection electrodes for high energy density and high output voltage.

PubMed

Tao, Jiayou; Liu, Nishuang; Rao, Jiangyu; Ding, Longwei; Al Bahrani, Majid Raissan; Li, Luying; Su, Jun; Gao, Yihua

2014-12-21

Asymmetric supercapacitors (ASCs) based on free-standing membranes with high energy density and high output voltage are reported. MnO(2) nanowire/carbon nanotube (CNT) composites and MoO(3) nanobelt/CNT composites are selected as the anode and the cathode materials of the devices, respectively. The ASC has a high volumetric capacitance of 50.2 F cm(-3) at a scan rate of 2 mV s(-1) and a high operation voltage window of 2.0 V. Especially, after a middle layer with an inner-connection structure was inserted between the anode and the cathode, the output voltage of the whole device can achieve 4.0 V. The full cell of series ASCs (SASC) with an inner-connection middle layer has a high energy density of 28.6 mW h cm(-3) at a power density of 261.4 mW cm(-3), and exhibits excellent cycling performance of 99.6% capacitance retention over 10,000 cycles. This strategy of designing the hybridized structure for SASCs provides a promising route for next-generation SCs with high energy density and high output voltage.

Ambipolar zinc-polyiodide electrolyte for a high-energy density aqueous redox flow battery

PubMed Central

Li, Bin; Nie, Zimin; Vijayakumar, M.; Li, Guosheng; Liu, Jun; Sprenkle, Vincent; Wang, Wei

2015-01-01

Redox flow batteries are receiving wide attention for electrochemical energy storage due to their unique architecture and advantages, but progress has so far been limited by their low energy density (~25 Wh l−1). Here we report a high-energy density aqueous zinc-polyiodide flow battery. Using the highly soluble iodide/triiodide redox couple, a discharge energy density of 167 Wh l−1 is demonstrated with a near-neutral 5.0 M ZnI2 electrolyte. Nuclear magnetic resonance study and density functional theory-based simulation along with flow test data indicate that the addition of an alcohol (ethanol) induces ligand formation between oxygen on the hydroxyl group and the zinc ions, which expands the stable electrolyte temperature window to from −20 to 50 °C, while ameliorating the zinc dendrite. With the high-energy density and its benign nature free from strong acids and corrosive components, zinc-polyiodide flow battery is a promising candidate for various energy storage applications. PMID:25709083

Coaxial wet-spun yarn supercapacitors for high-energy density and safe wearable electronics

NASA Astrophysics Data System (ADS)

Kou, Liang; Huang, Tieqi; Zheng, Bingna; Han, Yi; Zhao, Xiaoli; Gopalsamy, Karthikeyan; Sun, Haiyan; Gao, Chao

2014-05-01

Yarn supercapacitors have great potential in future portable and wearable electronics because of their tiny volume, flexibility and weavability. However, low-energy density limits their development in the area of wearable high-energy density devices. How to enhance their energy densities while retaining their high-power densities is a critical challenge for yarn supercapacitor development. Here we propose a coaxial wet-spinning assembly approach to continuously spin polyelectrolyte-wrapped graphene/carbon nanotube core-sheath fibres, which are used directly as safe electrodes to assembly two-ply yarn supercapacitors. The yarn supercapacitors using liquid and solid electrolytes show ultra-high capacitances of 269 and 177 mF cm-2 and energy densities of 5.91 and 3.84 μWh cm-2, respectively. A cloth supercapacitor superior to commercial capacitor is further interwoven from two individual 40-cm-long coaxial fibres. The combination of scalable coaxial wet-spinning technology and excellent performance of yarn supercapacitors paves the way to wearable and safe electronics.

Coaxial wet-spun yarn supercapacitors for high-energy density and safe wearable electronics

PubMed Central

Kou, Liang; Huang, Tieqi; Zheng, Bingna; Han, Yi; Zhao, Xiaoli; Gopalsamy, Karthikeyan; Sun, Haiyan; Gao, Chao

2014-01-01

Yarn supercapacitors have great potential in future portable and wearable electronics because of their tiny volume, flexibility and weavability. However, low-energy density limits their development in the area of wearable high-energy density devices. How to enhance their energy densities while retaining their high-power densities is a critical challenge for yarn supercapacitor development. Here we propose a coaxial wet-spinning assembly approach to continuously spin polyelectrolyte-wrapped graphene/carbon nanotube core-sheath fibres, which are used directly as safe electrodes to assembly two-ply yarn supercapacitors. The yarn supercapacitors using liquid and solid electrolytes show ultra-high capacitances of 269 and 177 mF cm−2 and energy densities of 5.91 and 3.84 μWh cm−2, respectively. A cloth supercapacitor superior to commercial capacitor is further interwoven from two individual 40-cm-long coaxial fibres. The combination of scalable coaxial wet-spinning technology and excellent performance of yarn supercapacitors paves the way to wearable and safe electronics. PMID:24786366

Ambipolar zinc-polyiodide electrolyte for a high-energy density aqueous redox flow battery.

PubMed

Li, Bin; Nie, Zimin; Vijayakumar, M; Li, Guosheng; Liu, Jun; Sprenkle, Vincent; Wang, Wei

2015-02-24

Redox flow batteries are receiving wide attention for electrochemical energy storage due to their unique architecture and advantages, but progress has so far been limited by their low energy density (~25 Wh l(-1)). Here we report a high-energy density aqueous zinc-polyiodide flow battery. Using the highly soluble iodide/triiodide redox couple, a discharge energy density of 167 Wh l(-1) is demonstrated with a near-neutral 5.0 M ZnI2 electrolyte. Nuclear magnetic resonance study and density functional theory-based simulation along with flow test data indicate that the addition of an alcohol (ethanol) induces ligand formation between oxygen on the hydroxyl group and the zinc ions, which expands the stable electrolyte temperature window to from -20 to 50 °C, while ameliorating the zinc dendrite. With the high-energy density and its benign nature free from strong acids and corrosive components, zinc-polyiodide flow battery is a promising candidate for various energy storage applications.

THEMIS two‐point measurements of the cross‐tail current density: A thick bifurcated current sheet in the near‐Earth plasma sheet

PubMed Central

2015-01-01

Abstract The basic properties of the near‐Earth current sheet from 8 RE to 12 RE were determined based on Time History of Events and Macroscale Interactions during Substorms (THEMIS) observations from 2007 to 2013. Ampere's law was used to estimate the current density when the locations of two spacecraft were suitable for the calculation. A total of 3838 current density observations were obtained to study the vertical profile. For typical solar wind conditions, the current density near (off) the central plane of the current sheet ranged from 1 to 2 nA/m2 (1 to 8 nA/m2). All the high current densities appeared off the central plane of the current sheet, indicating the formation of a bifurcated current sheet structure when the current density increased above 2 nA/m2. The median profile also showed a bifurcated structure, in which the half thickness was about 3 RE. The distance between the peak of the current density and the central plane of the current sheet was 0.5 to 1 RE. High current densities above 4 nA/m2 were observed in some cases that occurred preferentially during substorms, but they also occurred in quiet times. In contrast to the commonly accepted picture, these high current densities can form without a high solar wind dynamic pressure. In addition, these high current densities can appear in two magnetic configurations: tail‐like and dipolar structures. At least two mechanisms, magnetic flux depletion and new current system formation during the expansion phase, other than plasma sheet compression are responsible for the formation of the bifurcated current sheets. PMID:27722039

Breast density in multiethnic women presenting for screening mammography.

PubMed

Oppong, Bridget A; Dash, Chiranjeev; O'Neill, Suzanne; Li, Yinan; Makambi, Kepher; Pien, Edward; Makariou, Erini; Coleman, Tesha; Adams-Campbell, Lucile L

2018-05-01

Data on ethnic variations in breast density are limited and often not inclusive of underrepresented minorities. As breast density is associated with elevated breast cancer risk, investigating racial and ethnic difference may elucidate the observed differences in breast cancer risk among different populations. We reviewed breast density from initial screening of women from the Capital Breast Care Center and Georgetown University Hospital from 2010 to 2014. Patient demographics including race, age at screening, education, menopausal status, and body mass index were abstracted. We recorded the BI-RADS density categories: (1) "fatty," (2) "scattered fibroglandular densities," (3) "heterogeneously dense," and (4) "extremely dense." Multivariable unconditional logistic regression was used to identify predictors of breast density. Density categorization was recorded for 2146 women over the 5-year period, comprising Blacks (n = 940), Hispanics (n = 893), and Whites (n = 314). Analysis of subject characteristics by breast density showed that high category is observed in younger, Hispanic, nulliparous, premenopausal, and nonobese women (t-test or chi-square test, P-values <.0001). Obese women are 70% less likely to have high density. Being Hispanic, premenopausal, and nonobese were predictive of high density on logistic regression. In this analysis of density distribution in a diverse sample, Hispanic women have the highest breast density, followed by Blacks and Whites. Unique in our findings is women who identify as Hispanic have the highest breast density and lower rates of obesity. Further investigation of the impact of obesity on breast density, especially in the understudied Hispanic group is needed. © 2017 Wiley Periodicals, Inc.

Adolescent intake of animal fat and red meat in relation to premenopausal mammographic density

PubMed Central

Bertrand, Kimberly A.; Burian, Rosemarie A.; Eliassen, A. Heather; Willett, Walter C.; Tamimi, Rulla M.

2016-01-01

Purpose Adolescence is hypothesized to be a time period of particular susceptibility to breast cancer risk factors. Red meat and fat intake during high school was positively associated with risk of breast cancer among premenopausal women in the Nurses’ Health Study II (NHSII). High mammographic density is a strong predictor of breast cancer risk but there is limited research on dietary factors associated with breast density. To test the hypothesis that high intake of animal fat or red meat during adolescence is associated with mammographic density, we analyzed data from premenopausal women in the NHSII. Methods Participants recalled adolescent diet on a high school food frequency questionnaire. We assessed absolute and percent mammographic density on digitized analog film mammograms for 687 premenopausal women with no history of cancer. We used generalized linear regression to quantify associations of adolescent animal fat and red meat intake with mammographic density, adjusting for age, body mass index, and other predictors of mammographic density. Results Adolescent animal fat intake was significantly positively associated with premenopausal mammographic density, with a mean percent density of 39.2% in the lowest quartile of adolescent animal fat intake vs. 43.1% in the highest quartile (p-trend: 0.03). A non-significant positive association was also observed for adolescent red meat intake (p-trend: 0.14). Conclusions These findings suggest that higher adolescent animal fat intake is weakly associated with percent mammographic density in premenopausal women. PMID:26791521

Lack of effect of dietary fiber on serum lipids, glucose, and insulin in healthy young men fed high starch diets.

PubMed

Ullrich, I H; Albrink, M J

1982-07-01

Eight healthy young men were fed a 72% carbohydrate high starch diet either high or low in dietary fiber for 4 days in a double cross-over design. Both groups showed a slight transient increase in plasma triglyceride level and a decrease in total and high-density lipoprotein cholesterol. There were few differences in glucose and insulin levels after glucose and meal tolerance tests after each diet. Fasting triglycerides and high-density lipoprotein cholesterol were inversely related at base-line; insulin response to oral glucose was inversely related to high-density lipoprotein cholesterol levels at the end of the study. We conclude that a high carbohydrate high starch diet, whether high or low in fiber, caused little increase in triglycerides, with little difference between the high and low fiber diets. Dietary fiber did not influence the fall in plasma cholesterol or high-density lipoprotein cholesterol concentrations over and above that seen after the low fiber diet.

Linear Stability Analysis of Gravitational Effects on a Low-Density Gas Jet Injected into a High-Density Medium

NASA Technical Reports Server (NTRS)

Lawson, Anthony L.; Parthasarathy, Ramkumar N.

2005-01-01

The objective of this study was to determine the effects of buoyancy on the absolute instability of low-density gas jets injected into high-density gas mediums. Most of the existing analyses of low-density gas jets injected into a high-density ambient have been carried out neglecting effects of gravity. In order to investigate the influence of gravity on the near-injector development of the flow, a spatio-temporal stability analysis of a low-density round jet injected into a high-density ambient gas was performed. The flow was assumed to be isothermal and locally parallel; viscous and diffusive effects were ignored. The variables were represented as the sum of the mean value and a normal-mode small disturbance. An ordinary differential equation governing the amplitude of the pressure disturbance was derived. The velocity and density profiles in the shear layer, and the Froude number (signifying the effects of gravity) were the three important parameters in this equation. Together with the boundary conditions, an eigenvalue problem was formulated. Assuming that the velocity and density profiles in the shear layer to be represented by hyperbolic tangent functions, the eigenvalue problem was solved for various values of Froude number. The Briggs-Bers criterion was combined with the spatio-temporal stability analysis to determine the nature of the absolute instability of the jet whether absolutely or convectively unstable. The roles of the density ratio, Froude number, Schmidt number, and the lateral shift between the density and velocity profiles on the absolute instability of the jet were determined. Comparisons of the results with previous experimental studies show good agreement when the effects of these variables are combined together. Thus, the combination of these variables determines how absolutely unstable the jet will be.

Stabilization of electron-scale turbulence by electron density gradient in national spherical torus experiment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ruiz Ruiz, J.; White, A. E.; Ren, Y.

2015-12-15

Theory and experiments have shown that electron temperature gradient (ETG) turbulence on the electron gyro-scale, k{sub ⊥}ρ{sub e} ≲ 1, can be responsible for anomalous electron thermal transport in NSTX. Electron scale (high-k) turbulence is diagnosed in NSTX with a high-k microwave scattering system [D. R. Smith et al., Rev. Sci. Instrum. 79, 123501 (2008)]. Here we report on stabilization effects of the electron density gradient on electron-scale density fluctuations in a set of neutral beam injection heated H-mode plasmas. We found that the absence of high-k density fluctuations from measurements is correlated with large equilibrium density gradient, which ismore » shown to be consistent with linear stabilization of ETG modes due to the density gradient using the analytical ETG linear threshold in F. Jenko et al. [Phys. Plasmas 8, 4096 (2001)] and linear gyrokinetic simulations with GS2 [M. Kotschenreuther et al., Comput. Phys. Commun. 88, 128 (1995)]. We also found that the observed power of electron-scale turbulence (when it exists) is anti-correlated with the equilibrium density gradient, suggesting density gradient as a nonlinear stabilizing mechanism. Higher density gradients give rise to lower values of the plasma frame frequency, calculated based on the Doppler shift of the measured density fluctuations. Linear gyrokinetic simulations show that higher values of the electron density gradient reduce the value of the real frequency, in agreement with experimental observation. Nonlinear electron-scale gyrokinetic simulations show that high electron density gradient reduces electron heat flux and stiffness, and increases the ETG nonlinear threshold, consistent with experimental observations.« less

Population-Level Density Dependence Influences the Origin and Maintenance of Parental Care

PubMed Central

Reyes, Elijah; Thrasher, Patsy; Bonsall, Michael B.; Klug, Hope

2016-01-01

Parental care is a defining feature of animal breeding systems. We now know that both basic life-history characteristics and ecological factors influence the evolution of care. However, relatively little is known about how these factors interact to influence the origin and maintenance of care. Here, we expand upon previous work and explore the relationship between basic life-history characteristics (stage-specific rates of mortality and maturation) and the fitness benefits associated with the origin and the maintenance of parental care for two broad ecological scenarios: the scenario in which egg survival is density dependent and the case in which adult survival is density dependent. Our findings suggest that high offspring need is likely critical in driving the origin, but not the maintenance, of parental care regardless of whether density dependence acts on egg or adult survival. In general, parental care is more likely to result in greater fitness benefits when baseline adult mortality is low if 1) egg survival is density dependent or 2) adult mortality is density dependent and mutant density is relatively high. When density dependence acts on egg mortality, low rates of egg maturation and high egg densities are less likely to lead to strong fitness benefits of care. However, when density dependence acts on adult mortality, high levels of egg maturation and increasing adult densities are less likely to maintain care. Juvenile survival has relatively little, if any, effect on the origin and maintenance of egg-only care. More generally, our results suggest that the evolution of parental care will be influenced by an organism’s entire life history characteristics, the stage at which density dependence acts, and whether care is originating or being maintained. PMID:27093056

Z-Scan Analysis: a New Method to Determine the Oxidative State of Low-Density Lipoprotein and Its Association with Multiple Cardiometabolic Biomarkers

NASA Astrophysics Data System (ADS)

de Freitas, Maria Camila Pruper; Figueiredo Neto, Antonio Martins; Giampaoli, Viviane; da Conceição Quintaneiro Aubin, Elisete; de Araújo Lima Barbosa, Milena Maria; Damasceno, Nágila Raquel Teixeira

2016-04-01

The great atherogenic potential of oxidized low-density lipoprotein has been widely described in the literature. The objective of this study was to investigate whether the state of oxidized low-density lipoprotein in human plasma measured by the Z-scan technique has an association with different cardiometabolic biomarkers. Total cholesterol, high-density lipoprotein cholesterol, triacylglycerols, apolipoprotein A-I and apolipoprotein B, paraoxonase-1, and glucose were analyzed using standard commercial kits, and low-density lipoprotein cholesterol was estimated using the Friedewald equation. A sandwich enzyme-linked immunosorbent assay was used to detect electronegative low-density lipoprotein. Low-density lipoprotein and high-density lipoprotein sizes were determined by Lipoprint® system. The Z-scan technique was used to measure the non-linear optical response of low-density lipoprotein solution. Principal component analysis and correlations were used respectively to resize the data from the sample and test association between the θ parameter, measured with the Z-scan technique, and the principal component. A total of 63 individuals, from both sexes, with mean age 52 years (±11), being overweight and having high levels of total cholesterol and low levels of high-density lipoprotein cholesterol, were enrolled in this study. A positive correlation between the θ parameter and more anti-atherogenic pattern for cardiometabolic biomarkers together with a negative correlation for an atherogenic pattern was found. Regarding the parameters related with an atherogenic low-density lipoprotein profile, the θ parameter was negatively correlated with a more atherogenic pattern. By using Z-scan measurements, we were able to find an association between oxidized low-density lipoprotein state and multiple cardiometabolic biomarkers in samples from individuals with different cardiovascular risk factors.

Scalable high-power redox capacitors with aligned nanoforests of crystalline MnO₂ nanorods by high voltage electrophoretic deposition.

PubMed

Santhanagopalan, Sunand; Balram, Anirudh; Meng, Dennis Desheng

2013-03-26

It is commonly perceived that reduction-oxidation (redox) capacitors have to sacrifice power density to achieve higher energy density than carbon-based electric double layer capacitors. In this work, we report the synergetic advantages of combining the high crystallinity of hydrothermally synthesized α-MnO2 nanorods with alignment for high performance redox capacitors. Such an approach is enabled by high voltage electrophoretic deposition (HVEPD) technology which can obtain vertically aligned nanoforests with great process versatility. The scalable nanomanufacturing process is demonstrated by roll-printing an aligned forest of α-MnO2 nanorods on a large flexible substrate (1 inch by 1 foot). The electrodes show very high power density (340 kW/kg at an energy density of 4.7 Wh/kg) and excellent cyclability (over 92% capacitance retention over 2000 cycles). Pretreatment of the substrate and use of a conductive holding layer have also been shown to significantly reduce the contact resistance between the aligned nanoforests and the substrates. High areal specific capacitances of around 8500 μF/cm(2) have been obtained for each electrode with a two-electrode device configuration. Over 93% capacitance retention was observed when the cycling current densities were increased from 0.25 to 10 mA/cm(2), indicating high rate capabilities of the fabricated electrodes and resulting in the very high attainable power density. The high performance of the electrodes is attributed to the crystallographic structure, 1D morphology, aligned orientation, and low contact resistance.

A review of low density porous materials used in laser plasma experiments

NASA Astrophysics Data System (ADS)

Nagai, Keiji; Musgrave, Christopher S. A.; Nazarov, Wigen

2018-03-01

This review describes and categorizes the synthesis and properties of low density porous materials, which are commonly referred to as foams and are utilized for laser plasma experiments. By focusing a high-power laser on a small target composed of these materials, high energy and density states can be produced. In the past decade or so, various new target fabrication techniques have been developed by many laboratories that use high energy lasers and consequently, many publications and reviews followed these developments. However, the emphasis so far has been on targets that did not utilize low density porous materials. This review therefore, attempts to redress this balance and endeavors to review low density materials used in laser plasma experiments in recent years. The emphasis of this review will be on aspects of low density materials that are of relevance to high energy laser plasma experiments. Aspects of low density materials such as densities, elemental compositions, macroscopic structures, nanostructures, and characterization of these materials will be covered. Also, there will be a brief mention of how these aspects affect the results in laser plasma experiments and the constrictions that these requirements put on the fabrication of low density materials relevant to this field. This review is written from the chemists' point of view to aid physicists and the new comers to this field.

Significantly Enhanced Energy Storage Density by Modulating the Aspect Ratio of BaTiO3 Nanofibers

PubMed Central

Zhang, Dou; Zhou, Xuefan; Roscow, James; Zhou, Kechao; Wang, Lu; Luo, Hang; Bowen, Chris R.

2017-01-01

There is a growing need for high energy density capacitors in modern electric power supplies. The creation of nanocomposite systems based on one-dimensional nanofibers has shown great potential in achieving a high energy density since they can optimize the energy density by exploiting both the high permittivity of ceramic fillers and the high breakdown strength of the polymer matrix. In this paper, BaTiO3 nanofibers (NFs) with different aspect ratio were synthesized by a two-step hydrothermal method and the permittivity and energy storage of the P(VDF-HFP) nanocomposites were investigated. It is found that as the BaTiO3 NF aspect ratio and volume fraction increased the permittivity and maximum electric displacement of the nanocomposites increased, while the breakdown strength decreased. The nanocomposites with the highest aspect ratio BaTiO3 NFs exhibited the highest energy storage density at the same electric field. However, the nanocomposites with the lowest aspect ratio BaTiO3 NFs achieved the maximal energy storage density of 15.48 J/cm3 due to its higher breakdown strength. This contribution provides a potential route to prepare and tailor the properties of high energy density capacitor nanocomposites. PMID:28332636

Significantly Enhanced Energy Storage Density by Modulating the Aspect Ratio of BaTiO3 Nanofibers

NASA Astrophysics Data System (ADS)

Zhang, Dou; Zhou, Xuefan; Roscow, James; Zhou, Kechao; Wang, Lu; Luo, Hang; Bowen, Chris R.

2017-03-01

There is a growing need for high energy density capacitors in modern electric power supplies. The creation of nanocomposite systems based on one-dimensional nanofibers has shown great potential in achieving a high energy density since they can optimize the energy density by exploiting both the high permittivity of ceramic fillers and the high breakdown strength of the polymer matrix. In this paper, BaTiO3 nanofibers (NFs) with different aspect ratio were synthesized by a two-step hydrothermal method and the permittivity and energy storage of the P(VDF-HFP) nanocomposites were investigated. It is found that as the BaTiO3 NF aspect ratio and volume fraction increased the permittivity and maximum electric displacement of the nanocomposites increased, while the breakdown strength decreased. The nanocomposites with the highest aspect ratio BaTiO3 NFs exhibited the highest energy storage density at the same electric field. However, the nanocomposites with the lowest aspect ratio BaTiO3 NFs achieved the maximal energy storage density of 15.48 J/cm3 due to its higher breakdown strength. This contribution provides a potential route to prepare and tailor the properties of high energy density capacitor nanocomposites.

Significantly Enhanced Energy Storage Density by Modulating the Aspect Ratio of BaTiO3 Nanofibers.

PubMed

Zhang, Dou; Zhou, Xuefan; Roscow, James; Zhou, Kechao; Wang, Lu; Luo, Hang; Bowen, Chris R

2017-03-23

There is a growing need for high energy density capacitors in modern electric power supplies. The creation of nanocomposite systems based on one-dimensional nanofibers has shown great potential in achieving a high energy density since they can optimize the energy density by exploiting both the high permittivity of ceramic fillers and the high breakdown strength of the polymer matrix. In this paper, BaTiO 3 nanofibers (NFs) with different aspect ratio were synthesized by a two-step hydrothermal method and the permittivity and energy storage of the P(VDF-HFP) nanocomposites were investigated. It is found that as the BaTiO 3 NF aspect ratio and volume fraction increased the permittivity and maximum electric displacement of the nanocomposites increased, while the breakdown strength decreased. The nanocomposites with the highest aspect ratio BaTiO 3 NFs exhibited the highest energy storage density at the same electric field. However, the nanocomposites with the lowest aspect ratio BaTiO 3 NFs achieved the maximal energy storage density of 15.48 J/cm 3 due to its higher breakdown strength. This contribution provides a potential route to prepare and tailor the properties of high energy density capacitor nanocomposites.

Compaction of AWBA fuel pellets without binders (AWBA Development Program)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, R.G.R.

1982-08-01

Highly active oxide fuel powders, composed of UO/sub 2/, UO/sub 2/-ThO/sub 2/, or ThO/sub 2/, were compacted into ultra-high density pellets without the use of binders. The objective of the study was to select the optimum die lubricant for compacting these powders into pellets in preparation for sintering to densities in excess of 97% Theoretical Density. The results showed that sintered density was a function of both the lubricant bulk density and concentration with the lowest bulk density lubricant giving the highest sintered densities with a lubricant concentration of 0.1 weight percent. Five calcium and zinc stearates were evaluated withmore » a calcium stearate with a 15 lb/ft/sup 3/ bulk density being the best lubricant.« less

High-Performance Supercapacitors from Niobium Nanowire Yarns.

PubMed

Mirvakili, Seyed M; Mirvakili, Mehr Negar; Englezos, Peter; Madden, John D W; Hunter, Ian W

2015-07-01

The large-ion-accessible surface area of carbon nanotubes (CNTs) and graphene sheets formed as yarns, forests, and films enables miniature high-performance supercapacitors with power densities exceeding those of electrolytics while achieving energy densities equaling those of batteries. Capacitance and energy density can be enhanced by depositing highly pseudocapacitive materials such as conductive polymers on them. Yarns formed from carbon nanotubes are proposed for use in wearable supercapacitors. In this work, we show that high power, energy density, and capacitance in yarn form are not unique to carbon materials, and we introduce niobium nanowires as an alternative. These yarns show higher capacitance and energy per volume and are stronger and 100 times more conductive than similarly spun carbon multiwalled nanotube (MWNT) and graphene yarns. The long niobium nanowires, formed by repeated extrusion and drawing, achieve device volumetric peak power and energy densities of 55 MW·m(-3) (55 W·cm(-3)) and 25 MJ·m(-3) (7 mWh·cm(-3)), 2 and 5 times higher than that for state-of-the-art CNT yarns, respectively. The capacitance per volume of Nb nanowire yarn is lower than the 158 MF·m(-3) (158 F·cm(-3)) reported for carbon-based materials such as reduced graphene oxide (RGO) and CNT wet-spun yarns, but the peak power and energy densities are 200 and 2 times higher, respectively. Achieving high power in long yarns is made possible by the high conductivity of the metal, and achievement of high energy density is possible thanks to the high internal surface area. No additional metal backing is needed, unlike for CNT yarns and supercapacitors in general, saving substantial space. As the yarn is infiltrated with pseudocapacitive materials such as poly(3,4-ethylenedioxythiophene) (PEDOT), the energy density is further increased to 10 MJ·m(-3) (2.8 mWh·cm(-3)). Similar to CNT yarns, niobium nanowire yarns are highly flexible and show potential for weaving into textiles and use in wearable devices.

On the Origin of the High Column Density Turnover in the HI Column Density Distribution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Erkal, Denis; Gnedin, Nickolay Y.; Kravtsov, Andrey V.

We study the high column density regime of the HI column density distribution function and argue that there are two distinct features: a turnover at NHI ~ 10^21 cm^-2 which is present at both z=0 and z ~ 3, and a lack of systems above NHI ~ 10^22 cm^-2 at z=0. Using observations of the column density distribution, we argue that the HI-H2 transition does not cause the turnover at NHI ~ 10^21 cm^-2, but can plausibly explain the turnover at NHI > 10^22 cm^-2. We compute the HI column density distribution of individual galaxies in the THINGS sample andmore » show that the turnover column density depends only weakly on metallicity. Furthermore, we show that the column density distribution of galaxies, corrected for inclination, is insensitive to the resolution of the HI map or to averaging in radial shells. Our results indicate that the similarity of HI column density distributions at z=3 and z=0 is due to the similarity of the maximum HI surface densities of high-z and low-z disks, set presumably by universal processes that shape properties of the gaseous disks of galaxies. Using fully cosmological simulations, we explore other candidate physical mechanisms that could produce a turnover in the column density distribution. We show that while turbulence within GMCs cannot affect the DLA column density distribution, stellar feedback can affect it significantly if the feedback is sufficiently effective in removing gas from the central 2-3 kpc of high-redshift galaxies. Finally, we argue that it is meaningful to compare column densities averaged over ~ kpc scales with those estimated from quasar spectra which probe sub-pc scales due to the steep power spectrum of HI column density fluctuations observed in nearby galaxies.« less

Impact of Te and ne on edge current density profiles in ELM mitigated regimes on ASDEX Upgrade

NASA Astrophysics Data System (ADS)

Dunne, M. G.; Rathgeber, S.; Burckhart, A.; Fischer, R.; Giannone, L.; McCarthy, P. J.; Schneider, P. A.; Wolfrum, E.; the ASDEX Upgrade Team

2015-01-01

ELM resolved edge current density profiles are reconstructed using the CLISTE equilibrium code. As input, highly spatially and temporally resolved edge electron temperature and density profiles are used in addition to data from the extensive set of external poloidal field measurements available at ASDEX Upgrade, flux loop difference measurements, and current measurements in the scrape-off layer. Both the local and flux surface averaged current density profiles are analysed for several ELM mitigation regimes. The focus throughout is on the impact of altered temperature and density profiles on the current density. In particular, many ELM mitigation regimes rely on operation at high density. Two reference plasmas with type-I ELMs are analysed, one with a deuterium gas puff and one without, in order to provide a reference for the behaviour in type-II ELMy regimes and high density ELM mitigation with external magnetic perturbations at ASDEX Upgrade. For type-II ELMs it is found that while a similar pedestal top pressure is sustained at the higher density, the temperature gradient decreases in the pedestal. This results in lower local and flux surface averaged current densities in these phases, which reduces the drive for the peeling mode. No significant differences between the current density measured in the type-I phase and ELM mitigated phase is seen when external perturbations are applied, though the pedestal top density was increased. Finally, ELMs during the nitrogen seeded phase of a high performance discharge are analysed and compared to ELMs in the reference phase. An increased pedestal pressure gradient, which is the source of confinement improvement in impurity seeded discharges, causes a local current density increase. However, the increased Zeff in the pedestal acts to reduce the flux surface averaged current density. This dichotomy, which is not observed in other mitigation regimes, could act to stabilize both the ballooning mode and the peeling mode at the same time.

Pharmacological Regulation of Peroxisome Number in Glia

DTIC Science & Technology

2008-09-01

histone deacetylase HDL high - density lipoprotein LXR liver X receptor NPC Niemann Pick type C disease PBD peroxisome...transporters ABCA1 and ABCG1 with lipoproteins in the extracellular space, such as apoE; transportation to the liver occurs via high density lipoprotein ...mechanisms involved in the athero-protective effect of high density lipoproteins . Journal of internal medicine, 263, 256-273. Tobin, K. A., Steineger, H

Institute for High Energy Density Science

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wootton, Alan

The project objective was for the Institute of High Energy Density Science (IHEDS) at the University of Texas at Austin to help grow the High Energy Density (HED) science community, by connecting academia with the Z Facility (Z) and associated staff at Sandia National Laboratories (SNL). IHEDS was originally motivated by common interests and complementary capabilities at SNL and the University of Texas System (UTX), in 2008.

Multi-species genetic connectivity in a terrestrial habitat network.

PubMed

Marrotte, Robby R; Bowman, Jeff; Brown, Michael G C; Cordes, Chad; Morris, Kimberley Y; Prentice, Melanie B; Wilson, Paul J

2017-01-01

Habitat fragmentation reduces genetic connectivity for multiple species, yet conservation efforts tend to rely heavily on single-species connectivity estimates to inform land-use planning. Such conservation activities may benefit from multi-species connectivity estimates, which provide a simple and practical means to mitigate the effects of habitat fragmentation for a larger number of species. To test the validity of a multi-species connectivity model, we used neutral microsatellite genetic datasets of Canada lynx ( Lynx canadensis ), American marten ( Martes americana ), fisher ( Pekania pennanti ), and southern flying squirrel ( Glaucomys volans ) to evaluate multi-species genetic connectivity across Ontario, Canada. We used linear models to compare node-based estimates of genetic connectivity for each species to point-based estimates of landscape connectivity (current density) derived from circuit theory. To our knowledge, we are the first to evaluate current density as a measure of genetic connectivity. Our results depended on landscape context: habitat amount was more important than current density in explaining multi-species genetic connectivity in the northern part of our study area, where habitat was abundant and fragmentation was low. In the south however, where fragmentation was prevalent, genetic connectivity was correlated with current density. Contrary to our expectations however, locations with a high probability of movement as reflected by high current density were negatively associated with gene flow. Subsequent analyses of circuit theory outputs showed that high current density was also associated with high effective resistance, underscoring that the presence of pinch points is not necessarily indicative of gene flow. Overall, our study appears to provide support for the hypothesis that landscape pattern is important when habitat amount is low. We also conclude that while current density is proportional to the probability of movement per unit area, this does not imply increased gene flow, since high current density tends to be a result of neighbouring pixels with high cost of movement (e.g., low habitat amount). In other words, pinch points with high current density appear to constrict gene flow.

Effective reduction of LDL cholesterol by indigenous plant product.

PubMed

Bhardwaj, P K; Dasgupta, D J; Prashar, B S; Kaushal, S S

1994-03-01

A herbal powder containing guar gum, methi, tundika and meshasringi was administered to 30 control and 30 type 2 (non-insulin dependent) diabetes mellitus patients for a month. Total serum cholesterol and its fractions eg, high density lipoprotein, low density lipoproteins, very low density lipoproteins and serum triglyceride were determined before and after the trial period. Total and low density lipoprotein (LDL) cholesterols were reduced significantly after the therapy. There were no significant changes in high density lipoproteins (HDL), very low density lipoproteins (VLDL) or triglyceride levels. Side-effects eg, mild flatulence and looseness of bowel were noticed in less than 40% cases.

[CT diagnosis of hemorrhagic renal cysts].

PubMed

Wu, Y Z; Li, D T; Luo, J G

2001-06-28

CT signs of nineteen cases of hemorrhagic renal cysts that surgically and pathologically proved were analyzed. 8 of the 19 cases revealed as high density hemorrhagic lesion. CT signs in those 8 patients include low density rim sign, cyst immerging sign, and perirenal fascia thickening. The other 11 of 19 cases revealed as low density lesion. CT signs include thickened cyst wall and inhomogeneous density of the cystic content. The hounsfield unit of the lesion is correlated with the duration of disease. It is suggested that CT is valuable in diagnosis of high density hemorrhagic renal cysts, and it gives a clue to the diagnosis of low density hemorrhagic renal cysts.

Spatial variation and density-dependent dispersal in competitive coexistence.

PubMed Central

Amarasekare, Priyanga

2004-01-01

It is well known that dispersal from localities favourable to a species' growth and reproduction (sources) can prevent competitive exclusion in unfavourable localities (sinks). What is perhaps less well known is that too much emigration can undermine the viability of sources and cause regional competitive exclusion. Here, I investigate two biological mechanisms that reduce the cost of dispersal to source communities. The first involves increasing the spatial variation in the strength of competition such that sources can withstand high rates of emigration; the second involves reducing emigration from sources via density-dependent dispersal. I compare how different forms of spatial variation and modes of dispersal influence source viability, and hence source-sink coexistence, under dominance and pre-emptive competition. A key finding is that, while spatial variation substantially reduces dispersal costs under both types of competition, density-dependent dispersal does so only under dominance competition. For instance, when spatial variation in the strength of competition is high, coexistence is possible (regardless of the type of competition) even when sources experience high emigration rates; when spatial variation is low, coexistence is restricted even under low emigration rates. Under dominance competition, density-dependent dispersal has a strong effect on coexistence. For instance, when the emigration rate increases with density at an accelerating rate (Type III density-dependent dispersal), coexistence is possible even when spatial variation is quite low; when the emigration rate increases with density at a decelerating rate (Type II density-dependent dispersal), coexistence is restricted even when spatial variation is quite high. Under pre-emptive competition, density-dependent dispersal has only a marginal effect on coexistence. Thus, the diversity-reducing effects of high dispersal rates persist under pre-emptive competition even when dispersal is density dependent, but can be significantly mitigated under dominance competition if density-dependent dispersal is Type III rather than Type II. These results lead to testable predictions about source-sink coexistence under different regimes of competition, spatial variation and dispersal. They identify situations in which density-independent dispersal provides a reasonable approximation to species' dispersal patterns, and those under which consideration of density-dependent dispersal is crucial to predicting long-term coexistence. PMID:15306322

PREPARATION OF HIGH-DENSITY THORIUM OXIDE SPHERES

DOEpatents

McNees, R.A. Jr.; Taylor, A.J.

1963-12-31

A method of preparing high-density thorium oxide spheres for use in pellet beds in nuclear reactors is presented. Sinterable thorium oxide is first converted to free-flowing granules by means such as compression into a compact and comminution of the compact. The granules are then compressed into cubes having a density of 5.0 to 5.3 grams per cubic centimeter. The cubes are tumbled to form spheres by attrition, and the spheres are then fired at 1250 to 1350 deg C. The fired spheres are then polished and fired at a temperature above 1650 deg C to obtain high density. Spherical pellets produced by this method are highly resistant to mechanical attrition hy water. (AEC)

Design of Ultra-High-Power-Density Machine Optimized for Future Aircraft

NASA Technical Reports Server (NTRS)

Choi, Benjamin B.

2004-01-01

The NASA Glenn Research Center's Structural Mechanics and Dynamics Branch is developing a compact, nonpolluting, bearingless electric machine with electric power supplied by fuel cells for future "more-electric" aircraft with specific power in the projected range of 50 hp/lb, whereas conventional electric machines generate usually 0.2 hp/lb. The use of such electric drives for propulsive fans or propellers depends on the successful development of ultra-high-power-density machines. One possible candidate for such ultra-high-power-density machines, a round-rotor synchronous machine with an engineering current density as high as 20,000 A/sq cm, was selected to investigate how much torque and power can be produced.

Effects of population density on corticosterone levels of prairie voles in the field

PubMed Central

Blondel, Dimitri V.; Wallace, Gerard N.; Calderone, Stefanie; Gorinshteyn, Marija; St. Mary, Colette M.; Phelps, Steven M.

2015-01-01

High population density is often associated with increased levels of stress-related hormones, such as corticosterone (CORT). Prairie voles (Microtus ochrogaster) are a socially monogamous species known for their large population density fluctuations in the wild. Although CORT influences the social behavior of prairie voles in the lab, the effect of population density on CORT has not previously been quantified in this species in the field. We validated a non-invasive hormone assay for measuring CORT metabolites in prairie vole feces. We then used semi-natural enclosures to experimentally manipulate population density, and measured density effects on male space use and fecal CORT levels. Our enclosures generated patterns of space use and social interaction that were consistent with previous prairie vole field studies. Contrary to the positive relationship between CORT and density typical of other taxa, we found that lower population densities (80 animals/ha) produced higher fecal CORT than high densities (240/ha). Combined with prior work in the lab and field, the data suggest that high prairie vole population densities indicate favorable environments, perhaps through reduced predation risk. Lastly, we found that field animals had lower fecal CORT levels than laboratory-living animals. The data emphasize the usefulness of prairie voles as models for integrating ecological, evolutionary and mechanistic questions in social behavior. PMID:26342968

Hybrid system for rechargeable magnesium battery with high energy density

NASA Astrophysics Data System (ADS)

Chang, Zheng; Yang, Yaqiong; Wang, Xiaowei; Li, Minxia; Fu, Zhengwen; Wu, Yuping; Holze, Rudolf

2015-07-01

One of the main challenges of electrical energy storage (EES) is the development of environmentally friendly battery systems with high safety and high energy density. Rechargeable Mg batteries have been long considered as one highly promising system due to the use of low cost and dendrite-free magnesium metal. The bottleneck for traditional Mg batteries is to achieve high energy density since their output voltage is below 2.0 V. Here, we report a magnesium battery using Mg in Grignard reagent-based electrolyte as the negative electrode, a lithium intercalation compound in aqueous solution as the positive electrode, and a solid electrolyte as a separator. Its average discharge voltage is 2.1 V with stable discharge platform and good cycling life. The calculated energy density based on the two electrodes is high. These findings open another door to rechargeable magnesium batteries.

Spatial analysis of rural land development

Treesearch

Seong-Hoon Cho; David H. Newman

2005-01-01

This article examines patterns of rural land development and density using spatial econometric models with the application of Geographical Information System (GIS). The cluster patterns of both development and high-density development indicate that the spatially continuous expansions of development and high-density development exist in relatively remote rural areas....

Bonding Unidirectional Carbon Nanotube with Carbon for High Performance

DTIC Science & Technology

2015-06-24

the longest time of 80 minutes had an aerogel -like density, with CNT packing density lower than even the as-grown CNT array. This highly porous nature...nanotube foams with ultralow densities. Unlike other routes for fabrication of CNT aerogels , foam and sponges, this processing method allows the fast

Effects of maximal doses of atorvastatin versus rosuvastatin on small dense low-density lipoprotein cholesterol levels

USDA-ARS?s Scientific Manuscript database

Maximal doses of atorvastatin and rosuvastatin are highly effective in lowering low-density lipoprotein (LDL) cholesterol and triglyceride levels; however, rosuvastatin has been shown to be significantly more effective than atorvastatin in lowering LDL cholesterol and in increasing high-density lipo...

39 CFR Appendix A to Subpart A of... - Mail Classification Schedule

Code of Federal Regulations, 2012 CFR

2012-07-01

... Density and Saturation Letters High Density and Saturation Flats/Parcels Carrier Route Letters Flats Not... Package Services Single-Piece Parcel Post Inbound Surface Parcel Post (at UPU rates) Bound Printed Matter... Single-Piece First-Class Mail International Standard Mail (Regular and Nonprofit) High Density and...

Aligning Solution-Derived Carbon Nanotube Film with Full Surface Coverage for High-Performance Electronics Applications.

PubMed

Zhu, Ma-Guang; Si, Jia; Zhang, Zhiyong; Peng, Lian-Mao

2018-06-01

The main challenge for application of solution-derived carbon nanotubes (CNTs) in high performance field-effect transistor (FET) is how to align CNTs into an array with high density and full surface coverage. A directional shrinking transfer method is developed to realize high density aligned array based on randomly orientated CNT network film. Through transferring a solution-derived CNT network film onto a stretched retractable film followed by a shrinking process, alignment degree and density of CNT film increase with the shrinking multiple. The quadruply shrunk CNT films present well alignment, which is identified by the polarized Raman spectroscopy and electrical transport measurements. Based on the high quality and high density aligned CNT array, the fabricated FETs with channel length of 300 nm present ultrahigh performance including on-state current I on of 290 µA µm -1 (V ds = -1.5 V and V gs = -2 V) and peak transconductance g m of 150 µS µm -1 , which are, respectively, among the highest corresponding values in the reported CNT array FETs. High quality and high semiconducting purity CNT arrays with high density and full coverage obtained through this method promote the development of high performance CNT-based electronics. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The fate of a toxigenic strain of Staphylococcus aureus in vacuum-packaged bacon.

PubMed

Dempster, J F; Kelly, W R

1973-09-01

Pork was cured by (a) the Wiltshire method and (b) a hygienic sweet cure process. Representative samples of both bacons were inoculated at ;low' density (10(3) organisms/g.) and ;high' density (10(6) organisms/g.) with a toxin-producing strain of Staphylococcus aureus, ;High' and ;low' density samples of both bacons were each stored at 5 degrees C. for 42 days and 15 degrees C. for 21 days.Results indicated that the test organism at high inoculum density grew slowly in both bacons at 5 degrees C. The organism survived at 5 degrees C. in both ;low density' bacons. At 15 degrees C. the test organism grew; growth being more pronounced in the ;hygienic' than in Wiltshire bacon.

PGC1α is required for the induction of contact inhibition by suppressing ROS.

PubMed

Yang, Seungyeon; Hwang, Sunsook; Jang, Jiho; Kim, Minjoong; Gwak, Jihye; Jeong, Seung Min

2018-05-16

Contact inhibition (CI) is an important tumor-suppressive mechanism that arrests cell cycle when cells reach high density. Indeed, CI is aberrantly absent in cancer cells and the dysregulation of this can contribute to tumorigenesis. Previously, it has been shown that reactive oxygen species (ROS) levels are repressed at high cell density, which is required for CI, but no molecular mechanism of this ROS regulation has been reported. Here, we show that PGC1α regulates cell density-dependent CI. PGC1α is markedly induced in response to high cell density and suppresses ROS production. Although cellular ROS levels are progressively decreased with increasing cell density, knockdown of PGC1α results in a defect of density-dependent ROS suppression. Importantly, PGC1α knockdown cells become less sensitive to high cell density and exhibit loss of CI. Mechanistically, PGC1α represses ROS production by inducing mitochondrial SIRT3, and thus SIRT3 overexpression rescues the defects of CI by PGC1α knockdown. These results demonstrate that mitochondrial ROS production is a crucial regulator of cell proliferation and identify a new role of PGC1α in CI. Copyright © 2018 Elsevier Inc. All rights reserved.

High-Current-Density Vertical-Tunneling Transistors from Graphene/Highly Doped Silicon Heterostructures.

PubMed

Liu, Yuan; Sheng, Jiming; Wu, Hao; He, Qiyuan; Cheng, Hung-Chieh; Shakir, Muhammad Imran; Huang, Yu; Duan, Xiangfeng

2016-06-01

Scalable fabrication of vertical-tunneling transistors is presented based on heterostructures formed between graphene, highly doped silicon, and its native oxide. Benefiting from the large density of states of highly doped silicon, the tunneling transistors can deliver a current density over 20 A cm(-2) . This study demonstrates that the interfacial native oxide plays a crucial role in governing the carrier transport in graphene-silicon heterostructures. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effects of working pressure and annealing on bulk density and nanopore structures in amorphous In-Ga-Zn-O thin-film transistors

NASA Astrophysics Data System (ADS)

Ide, Keisuke; Kikuchi, Mitsuho; Ota, Masato; Sasase, Masato; Hiramatsu, Hidenori; Kumomi, Hideya; Hosono, Hideo; Kamiya, Toshio

2017-03-01

Microstructures of amorphous In-Ga-Zn-O (a-IGZO) thin films of different densities were analyzed. Device-quality a-IGZO films were deposited under optimum conditions, e.g., the total pressure P tot = 0.55 Pa produced high film densities of ˜6.1 g/cm3, while a very high P tot = 5.0 Pa produced low film densities of 5.5 g/cm3. Both films formed uniform high-density layers in the vicinity of the glass substrate, 10-20 nm in thickness depending on P tot, while their growth mode changed to a sparse columnar structure in thicker regions. X-ray reflectivity and in situ spectroscopic ellipsometry provided different results on densification by post deposition thermal annealing; i.e., the latter has a higher sensitivity. High-Z-contrast images obtained by high-angle annular dark-field scanning transmission electron microscopy were also useful for detecting nanometer-size non uniformity even in device-quality a-IGZO films.

Local epitaxial growth of ZrO2 on Ge (100) substrates by atomic layer epitaxy

NASA Astrophysics Data System (ADS)

Kim, Hyoungsub; Chui, Chi On; Saraswat, Krishna C.; McIntyre, Paul C.

2003-09-01

High-k dielectric deposition processes for gate dielectric preparation on Si surfaces usually result in the unavoidable and uncontrolled formation of a thin interfacial oxide layer. Atomic layer deposition of ˜55-Å ZrO2 film on a Ge (100) substrate using ZrCl4 and H2O at 300 °C was found to produce local epitaxial growth [(001) Ge//(001) ZrO2 and [100] Ge//[100] ZrO2] without a distinct interfacial layer, unlike the situation observed when ZrO2 is deposited using the same method on Si. Relatively large lattice mismatch (˜10%) between ZrO2 and Ge produced a high areal density of interfacial misfit dislocations. Large hysteresis (>200 mV) and high frequency dispersion were observed in capacitance-voltage measurements due to the high density of interface states. However, a low leakage current density, comparable to values obtained on Si substrates, was observed with the same capacitance density regardless of the high defect density.

Aphid vector population density determines the emergence of necrogenic satellite RNAs in populations of cucumber mosaic virus.

PubMed

Betancourt, Mónica; Fraile, Aurora; Milgroom, Michael G; García-Arenal, Fernando

2016-06-01

The satellite RNAs of cucumber mosaic virus (CMV) that induce systemic necrosis in tomato plants (N-satRNA) multiply to high levels in the infected host while severely depressing CMV accumulation and, hence, its aphid transmission efficiency. As N-satRNAs are transmitted into CMV particles, the conditions for N-satRNA emergence are not obvious. Model analyses with realistic parameter values have predicted that N-satRNAs would invade CMV populations only when transmission rates are high. Here, we tested this hypothesis experimentally by passaging CMV or CMV+N-satRNAs at low or high aphid densities (2 or 8 aphids/plant). As predicted, high aphid densities were required for N-satRNA emergence. The results showed that at low aphid densities, random effects due to population bottlenecks during transmission dominate the epidemiological dynamics of CMV/CMV+N-satRNA. The results suggest that maintaining aphid populations at low density will prevent the emergence of highly virulent CMV+N-satRNA isolates.

Nano-Magnets and Additive Manufacturing for Electric Motors

NASA Technical Reports Server (NTRS)

Misra, Ajay K.

2014-01-01

High power density is required for application of electric motors in hybrid electric propulsion. Potential path to achieve high power density in electric motors include advanced materials, lightweight thermal management, lightweight structural concepts, high power density power electronics, and advanced manufacturing. This presentation will focus on two key technologies for achieving high power density, advanced magnets and additive manufacturing. The maximum energy product in current magnets is reaching their theoretical limits as a result of material and process improvements. Future improvements in the maximum energy product for magnets can be achieved through development of nanocomposite magnets combining the hard magnetic phase and soft magnetic phase at the nanoscale level. The presentation will provide an overview of the current state of development for nanocomposite magnets and the future path for doubling the maximum energy product. The other part of the presentation will focus on the role of additive manufacturing in fabrication of high power density electric motors. The presentation will highlight the potential opportunities for applying additive manufacturing to fabricate electric motors.

STED Imaging of Golgi Dynamics with Cer-SiR: A Two-Component, Photostable, High-Density Lipid Probe for Live Cells.

PubMed

Erdmann, Roman S; Toomre, Derek; Schepartz, Alanna

2017-01-01

Long time-lapse super-resolution imaging in live cells requires a labeling strategy that combines a bright, photostable fluorophore with a high-density localization probe. Lipids are ideal high-density localization probes, as they are >100 times more abundant than most membrane-bound proteins and simultaneously demark the boundaries of cellular organelles. Here, we describe Cer-SiR, a two-component, high-density lipid probe that is exceptionally photostable. Cer-SiR is generated in cells via a bioorthogonal reaction of two components: a ceramide lipid tagged with trans-cyclooctene (Cer-TCO) and a reactive, photostable Si-rhodamine dye (SiR-Tz). These components assemble within the Golgi apparatus of live cells to form Cer-SiR. Cer-SiR is benign to cellular function, localizes within the Golgi at a high density, and is sufficiently photostable to enable visualization of Golgi structure and dynamics by 3D confocal or long time-lapse STED microscopy.

Observations of the diurnal dependence of the high-latitude F region ion density by DMSP satellites

NASA Technical Reports Server (NTRS)

Sojka, J. J.; Raitt, W. J.; Schunk, R. W.; Rich, F. J.; Sagalyn, R. C.

1982-01-01

Data from the DMSP F2 and F4 satellites for the period December 5-10, 1979, have been used to study the diurnal dependence of the high-latitude ion density at 800-km altitude. A 24-hour periodicity in the minimum orbital density (MOD) during a crossing of the high-latitude region is observed in both the winter and summer hemispheres. The phase of the variation in MOD is such that it has a minimum during the 24-hour period between 0700 and 0900 UT. Both the long-term variation of the high-latitude ion density on a time scale of days, and the orbit-by-orbit variations at the same geomagnetic location in the northern (winter) hemisphere for the magnetically quiet time period chosen, show good qualitative agreement with the diurnal dependence predicted by a theoretical model of the ionospheric density at high latitudes under conditions of low convection speeds (Sojka et al., 1981).

Nanoscale investigation of the piezoelectric properties of perovskite ferroelectrics and III-nitrides

NASA Astrophysics Data System (ADS)

Rodriguez, Brian Joseph

Nanoscale characterization of the piezoelectric and polarization related properties of III-Nitrides by piezoresponse force microscopy (PFM), electrostatic force microscopy (EFM) and scanning Kelvin probe microscopy (SKPM) resulted in the measurement of piezoelectric constants, surface charge and surface potential. Photo-electron emission microscopy (PEEM) was used to determine the local electronic band structure of a GaN-based lateral polarity heterostructure (GaN-LPH). Nanoscale characterization of the imprint and switching behavior of ferroelectric thin films by PFM resulted in the observation of domain pinning, while nanoscale characterization of the spatial variations in the imprint and switching behavior of integrated (111)-oriented PZT-based ferroelectric random access memory (FRAM) capacitors by PFM have revealed a significant difference in imprint and switching behavior between the inner and outer parts of capacitors. The inner regions of the capacitors are typically negatively imprinted and consequently tend to switch back after being poled by a positive bias, while regions at the edge of the capacitors tend to exhibit more symmetric hysteresis behavior. Evidence was obtained indicating that mechanical stress conditions in the central regions of the capacitors can lead to incomplete switching. A combination of vertical and lateral piezoresponse force microscopy (VPFM and LPFM, respectively) has been used to map the out-of-plane and in-plane polarization distribution, respectively, of integrated (111)-oriented PZT-based capacitors, which revealed poled capacitors are in a polydomain state.

Arctic pathways of Pacific Water: Arctic Ocean Model Intercomparison experiments

PubMed Central

Karcher, Michael; Proshutinsky, Andrey; Gerdes, Rüdiger; de Cuevas, Beverly; Golubeva, Elena; Kauker, Frank; Nguyen, An T.; Platov, Gennady A.; Wadley, Martin; Watanabe, Eiji; Coward, Andrew C.; Nurser, A. J. George

2016-01-01

Abstract Pacific Water (PW) enters the Arctic Ocean through Bering Strait and brings in heat, fresh water, and nutrients from the northern Bering Sea. The circulation of PW in the central Arctic Ocean is only partially understood due to the lack of observations. In this paper, pathways of PW are investigated using simulations with six state‐of‐the art regional and global Ocean General Circulation Models (OGCMs). In the simulations, PW is tracked by a passive tracer, released in Bering Strait. Simulated PW spreads from the Bering Strait region in three major branches. One of them starts in the Barrow Canyon, bringing PW along the continental slope of Alaska into the Canadian Straits and then into Baffin Bay. The second begins in the vicinity of the Herald Canyon and transports PW along the continental slope of the East Siberian Sea into the Transpolar Drift, and then through Fram Strait and the Greenland Sea. The third branch begins near the Herald Shoal and the central Chukchi shelf and brings PW into the Beaufort Gyre. In the models, the wind, acting via Ekman pumping, drives the seasonal and interannual variability of PW in the Canadian Basin of the Arctic Ocean. The wind affects the simulated PW pathways by changing the vertical shear of the relative vorticity of the ocean flow in the Canada Basin. PMID:27818853

Bacterial communities in Arctic first-year drift ice during the winter/spring transition.

PubMed

Eronen-Rasimus, Eeva; Piiparinen, Jonna; Karkman, Antti; Lyra, Christina; Gerland, Sebastian; Kaartokallio, Hermanni

2016-08-01

Horizontal and vertical variability of first-year drift-ice bacterial communities was investigated along a North-South transect in the Fram Strait during the winter/spring transition. Two different developmental stages were captured along the transect based on the prevailing environmental conditions and the differences in bacterial community composition. The differences in the bacterial communities were likely driven by the changes in sea-ice algal biomass (2.6-5.6 fold differences in chl-a concentrations). Copiotrophic genera common in late spring/summer sea ice, such as Polaribacter, Octadecabacter and Glaciecola, dominated the bacterial communities, supporting the conclusion that the increase in the sea-ice algal biomass was possibly reflected in the sea-ice bacterial communities. Of the dominating bacterial genera, Polaribacter seemed to benefit the most from the increase in algal biomass, since they covered approximately 39% of the total community at the southernmost stations with higher (>6 μg l(-1) ) chl-a concentrations and only 9% at the northernmost station with lower chl-a concentrations (<6 μg l(-1) ). The sea-ice bacterial communities also varied between the ice horizons at all three stations and thus we recommend that for future studies multiple ice horizons be sampled to cover the variability in sea-ice bacterial communities in spring. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

Ikaite crystals in melting sea ice - implications for pCO2 and pH levels in Arctic surface waters

NASA Astrophysics Data System (ADS)

Rysgaard, S.; Glud, R. N.; Lennert, K.; Cooper, M.; Halden, N.; Leakey, R. J. G.; Hawthorne, F. C.; Barber, D.

2012-03-01

A major issue of Arctic marine science is to understand whether the Arctic Ocean is, or will be, a source or sink for air-sea CO2 exchange. This has been complicated by the recent discoveries of ikaite (CaCO3·6H2O) in Arctic and Antarctic sea ice, which indicate that multiple chemical transformations occur in sea ice with a possible effect on CO2 and pH conditions in surface waters. Here we report on biogeochemical conditions, microscopic examinations and x-ray diffraction analysis of single crystals from an actively melting 1.7 km2 (0.5-1 m thick) drifting ice floe in the Fram Strait during summer. Our findings show that ikaite crystals are present throughout the sea ice but with larger crystals appearing in the upper ice layers. Ikaite crystals placed at elevated temperatures gradually disintegrated into smaller crystallites and dissolved. During our field campaign in late June, melt reduced the ice flow thickness by ca. 0.2 m per week and resulted in an estimated 1.6 ppm decrease of pCO2 in the ocean surface mixed layer. This corresponds to an air-sea CO2 uptake of 11 mmol m-2 sea ice d-1 or to 3.5 ton km-2 ice floe week-1.

Laser Scribed Graphene Cathode for Next Generation of High Performance Hybrid Supercapacitors.

PubMed

Lee, Seung-Hwan; Kim, Jin Hyeon; Yoon, Jung-Rag

2018-05-25

Hybrid supercapacitors have been regarded as next-generation energy storage devices due to their outstanding performances. However, hybrid supercapacitors remain a great challenge to enhance the energy density of hybrid supercapacitors. Herein, a novel approach for high-energy density hybrid supercapacitors based on a laser scribed graphene cathode and AlPO 4 -carbon hybrid coated H 2 Ti 12 O 25 (LSG/H-HTO) was designed. Benefiting from high-energy laser scribed graphene and high-power H-HTO, it was demonstrated that LSG/H-HTO delivers superior energy and power densities with excellent cyclability. Compared to previous reports on other hybrid supercapacitors, LSG/H-HTO electrode composition shows extraordinary energy densities of ~70.8 Wh/kg and power densities of ~5191.9 W/kg. Therefore, LSG/H-HTO can be regarded as a promising milestone in hybrid supercapacitors.

High volumetric supercapacitor with a long life span based on polymer dots and graphene sheets

NASA Astrophysics Data System (ADS)

Wei, Ji-Shi; Chen, Jie; Ding, Hui; Zhang, Peng; Wang, Yong-Gang; Xiong, Huan-Ming

2017-10-01

A series of polymer dots/graphene sheets composites with high densities are prepared and tested for supercapacitors. Polymer dots (PDs) are synthesized by one-step method at room temperature. They can effectively increase surface areas of the composites (almost 10 times), and the functional groups from PDs produce high pseudocapacitance, so that the samples exhibit high specific capacitances (e. g., 364.2 F cm-3 at 1 A g-1) and high cycling stability (e. g., more than 95% of the initial capacity retention over 10 000 cycles at different current densities). The optimal sample is employed to fabricate a symmetric supercapacitor, which exhibits an energy density up to 8 Wh L-1 and a power density up to 11 800 W L-1, respectively.

Improvements in processing characteristics and engineering properties of wood flour-filled high density polyethylene composite sheeting in the presence of hollow glass microspheres

Treesearch

Baris Yalcin; Steve E Amos; Andrew S D Souza; Craig M Clemons; I Sedat Gunes; Troy K Ista

2012-01-01

Hollow glass microspheres were introduced into wood flour/high density polyethylene composites by melt compounding in a twin-screw extruder. The prepared composites were subsequently converted to extruded profiles in order to obtain composite sheeting. The presence of hollow glass microspheres highly reduced the density of the extruded sheets down to 0.9 g/cc, while...

Associations of Education Level and Bone Density Tests among Cognitively Intact Elderly White Women in Managed Medicare

PubMed Central

Shi, Di; Yin, Michael T.; Shi, Qiuhu; Hoover, Donald R.

2012-01-01

Objectives. To examine associations between having bone density tests and level of education among white elderly women in managed Medicare. Method. Data from the ninth through twelfth cohort (2006–2009) of the Medicare Health Outcome Survey (HOS) of managed Medicare plans were analyzed; 239331 white elderly women were included. Respondents were grouped by education level and the percentages of respondents who had lifetime bone density testing done among each group were analyzed. Results. 62.7% of respondents with less than a high school education reported previously taking a bone density test. This was lower than the 73.8% for respondents who completed high school and the 81.0% for respondents with more than a high school education. When potential confounding factors such as age, body mass index, marital status, smoking history, year of HOS survey, and region were factored in, the odds ratios of having a bone density test when compared to respondents with less than a high school education were 1.61 and 2.39, respectively, for those with just a high school education and more than a high school education (P < 0.001). Conclusion. Higher education was independently associated with greater use of bone density test in these elderly white women. PMID:23056041

High-Performance Microsupercapacitors Based on Bioinspired Graphene Microfibers.

PubMed

Pan, Hui; Wang, Dawei; Peng, Qingfa; Ma, Jun; Meng, Xin; Zhang, Yaopeng; Ma, Yuning; Zhu, Shenmin; Zhang, Di

2018-03-28

The miniaturization of portable electronic devices has fueled the development of microsupercapacitors that hold great potential to complement or even replace microbatteries and electrolytic capacitors. In spite of recent developments taking advantage of printing and lithography, it remains a great challenge to attain a high energy density without sacrificing the power density. Herein, a new protocol mimicking the spider's spinning process is developed to create highly oriented microfibers from graphene-based composites via a purpose-designed microfluidic chip. The orientation provides the microfibers with an electrical conductivity of ∼3 × 10 4 S m -1 , which leads to a high power density; the energy density is sustained by nanocarbons and high-purity metallic molybdenum disulfide. The microfibers are patterned in-plane to fabricate asymmetric microsupercapacitors for flexible and on-chip energy storage. The on-chip microsupercapacitor with a high pattern resolution of 100 μm delivers energy density up to the order of 10 -2 W h cm -3 and retains an ultrahigh power density exceeding 100 W cm -3 in an aqueous electrolyte. This work provides new design of flexible and on-chip asymmetric microsupercapacitors based on microfibers. The unique biomimetic microfluidic fabrication of graphene microfibers for energy storage may also stimulate thinking of the bionic design in many other fields.

CT of abdominal tuberculosis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Epstein, B.M.; Mann, J.H.

1982-11-01

Intraabdominal tuberculosis (TB) presents with a wide variety of clinical and radiologic features. Besides the reported computed tomographic (CT) finding of high-density ascites in tuberculous peritonitis, this report describes additional CT features highly suggestive of abdominal tuberculosis in eight cases: (1) irregular soft-tissue densities in the omental area; (2) low-density masses surrounded by thick solid rims; (3) a disorganized appearance of soft-tissue densities, fluid, and bowel loops forming a poorly defined mass; (4) low-density lymph nodes with a multilocular appearance after intravenous contrast administration; and (5) possibly high-density ascites. The differential diagnosis of these features include lymphoma, various forms ofmore » peritonitis, peritoneal carcinomatosis, and peritoneal mesothelioma. It is important that the CT features of intraabdominal tuberculosis be recognized in order that laparotomy be avoided and less invasive procedures (e.g., laparoscopy, biopsy, or a trial of antituberculous therapy) be instituted.« less

Moiré deflectometry using the Talbot-Lau interferometer as refraction diagnostic for High Energy Density plasmas at energies below 10 keV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Valdivia, M. P.; Stutman, D.; Finkenthal, M.

2014-07-15

The highly localized density gradients expected in High Energy Density (HED) plasma experiments can be characterized by x-ray phase-contrast imaging in addition to conventional attenuation radiography. Moiré deflectometry using the Talbot-Lau grating interferometer setup is an attractive HED diagnostic due to its high sensitivity to refraction induced phase shifts. We report on the adaptation of such a system for operation in the sub-10 keV range by using a combination of free standing and ultrathin Talbot gratings. This new x-ray energy explored matches well the current x-ray backlighters used for HED experiments, while also enhancing phase effects at lower electron densities.more » We studied the performance of the high magnification, low energy Talbot-Lau interferometer, for single image phase retrieval using Moiré fringe deflectometry. Our laboratory and simulation studies indicate that such a device is able to retrieve object electron densities from phase shift measurements. Using laboratory x-ray sources from 7 to 15 μm size we obtained accurate simultaneous measurements of refraction and attenuation for both sharp and mild electron density gradients.« less

Moiré deflectometry using the Talbot-Lau interferometer as refraction diagnostic for high energy density plasmas at energies below 10 keV.

PubMed

Valdivia, M P; Stutman, D; Finkenthal, M

2014-07-01

The highly localized density gradients expected in High Energy Density (HED) plasma experiments can be characterized by x-ray phase-contrast imaging in addition to conventional attenuation radiography. Moiré deflectometry using the Talbot-Lau grating interferometer setup is an attractive HED diagnostic due to its high sensitivity to refraction induced phase shifts. We report on the adaptation of such a system for operation in the sub-10 keV range by using a combination of free standing and ultrathin Talbot gratings. This new x-ray energy explored matches well the current x-ray backlighters used for HED experiments, while also enhancing phase effects at lower electron densities. We studied the performance of the high magnification, low energy Talbot-Lau interferometer, for single image phase retrieval using Moiré fringe deflectometry. Our laboratory and simulation studies indicate that such a device is able to retrieve object electron densities from phase shift measurements. Using laboratory x-ray sources from 7 to 15 μm size we obtained accurate simultaneous measurements of refraction and attenuation for both sharp and mild electron density gradients.

Effects of plant density on recombinant hemagglutinin yields in an Agrobacterium-mediated transient gene expression system using Nicotiana benthamiana plants.

PubMed

Fujiuchi, Naomichi; Matsuda, Ryo; Matoba, Nobuyuki; Fujiwara, Kazuhiro

2017-08-01

Agrobacterium-mediated transient expression systems enable plants to rapidly produce a wide range of recombinant proteins. To achieve economically feasible upstream production and downstream processing, it is beneficial to obtain high levels of two yield-related quantities of upstream production: recombinant protein content per fresh mass of harvested biomass (g gFM -1 ) and recombinant protein productivity per unit area-time (g m -2 /month). Here, we report that the density of Nicotiana benthamiana plants during upstream production had significant impacts on the yield-related quantities of recombinant hemagglutinin (HA). The two quantities were smaller at a high plant density of 400 plants m -2 than at a low plant density of 100 plants m -2 . The smaller quantities at the high plant density were attributed to: (i) a lower HA content in young leaves, which usually have high HA accumulation potentials; (ii) a lower biomass allocation to the young leaves; and (iii) a high area-time requirement for plants. Thus, plant density is a key factor for improving upstream production in Agrobacterium-mediated transient expression systems. Biotechnol. Bioeng. 2017;114: 1762-1770. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Plasma devices to guide and collimate a high density of MeV electrons.

PubMed

Kodama, R; Sentoku, Y; Chen, Z L; Kumar, G R; Hatchett, S P; Toyama, Y; Cowan, T E; Freeman, R R; Fuchs, J; Izawa, Y; Key, M H; Kitagawa, Y; Kondo, K; Matsuoka, T; Nakamura, H; Nakatsutsumi, M; Norreys, P A; Norimatsu, T; Snavely, R A; Stephens, R B; Tampo, M; Tanaka, K A; Yabuuchi, T

2004-12-23

The development of ultra-intense lasers has facilitated new studies in laboratory astrophysics and high-density nuclear science, including laser fusion. Such research relies on the efficient generation of enormous numbers of high-energy charged particles. For example, laser-matter interactions at petawatt (10(15) W) power levels can create pulses of MeV electrons with current densities as large as 10(12) A cm(-2). However, the divergence of these particle beams usually reduces the current density to a few times 10(6) A cm(-2) at distances of the order of centimetres from the source. The invention of devices that can direct such intense, pulsed energetic beams will revolutionize their applications. Here we report high-conductivity devices consisting of transient plasmas that increase the energy density of MeV electrons generated in laser-matter interactions by more than one order of magnitude. A plasma fibre created on a hollow-cone target guides and collimates electrons in a manner akin to the control of light by an optical fibre and collimator. Such plasma devices hold promise for applications using high energy-density particles and should trigger growth in charged particle optics.

[Research on electron density in DC needle-plate corona discharge at atmospheric pressure].

PubMed

Liu, Zhi-Qiang; Guo, Wei; Liu, Tao-Tao; Wu, Wen-Shuo; Liu, Shu-Min

2013-11-01

Using needle-plate discharge device, corona discharge experiment was done in the atmosphere. Through photo of spot size of light-emitting area, the relationship between the voltage and thickness of corona layer was discussed. When the distance between tip and plate is fixed, the thickness of corona layer increases with the increase in voltage; when the voltage is fixed, the thickness of corona layer decreases with the increase in the distance between tip and plate. As spectral intensity of N2 (C3pi(u)) (337.1 nm)reflects high energy electron density, it was measured with emission spectrometry. The results show that high energy electron density is the biggest near the needle tip and the relationship between high energy electron density and voltage is basically linear increasing. Fixing voltage, high energy electron density decreases with the increase in the distance between tip and plate. When the voltage and the distance between tip and plate are fixed, the high energy electron density increases with the decrease in the curvature radius of needle tip. These results are of great importance for the study of plasma parameters of corona discharge.

Dissection of the genetic architecture underlying the plant density response by mapping plant height-related traits in maize (Zea mays L.).

PubMed

Ku, Lixia; Zhang, Liangkun; Tian, Zhiqiang; Guo, Shulei; Su, Huihui; Ren, Zhenzhen; Wang, Zhiyong; Li, Guohui; Wang, Xiaobo; Zhu, Yuguang; Zhou, Jinlong; Chen, Yanhui

2015-08-01

Plant height is one of the most heritable traits in maize (Zea mays L.). Understanding the genetic control of plant height is important for elucidating the molecular mechanisms that regulate maize development. To investigate the genetic basis of the plant height response to density in maize, we evaluated the effects of two different plant densities (60,000 and 120,000 plant/hm(2)) on three plant height-related traits (plant height, ear height, and ear height-to-plant height ratio) using four sets of recombinant inbred line populations. The phenotypes observed under the two-plant density treatments indicated that high plant density increased the phenotypic performance values of the three measured traits. Twenty-three quantitative trait loci (QTLs) were detected under the two-plant density treatments, and five QTL clusters were located. Nine QTLs were detected under the low plant density treatment, and seven QTLs were detected under the high plant density treatment. Our results suggested that plant height may be controlled mainly by a common set of genes that could be influenced by additional genetic mechanisms when the plants were grown under high plant density. Fine mapping for genetic regions of the stable QTLs across different plant density environments may provide additional information about their different responses to density. The results presented here provide useful information for further research and will help to reveal the molecular mechanisms related to plant height in response to density.

Unimodal relationship between small-scale barnacle recruitment and the density of pre-existing barnacle adults.

PubMed

Scrosati, Ricardo A; Ellrich, Julius A

2017-01-01

Recruitment is a key demographic process for population persistence. This paper focuses on barnacle ( Semibalanus balanoides ) recruitment. In rocky intertidal habitats from the Gulf of St. Lawrence coast of Nova Scotia (Canada), ice scour is common during the winter. At the onset of intertidal barnacle recruitment in early May (after sea ice has fully melted), mostly only adult barnacles and bare substrate are visible at high elevations in wave-exposed habitats. We conducted a multiannual study to investigate if small-scale barnacle recruitment could be predicted from the density of pre-existing adult barnacles. In a year that exhibited a wide adult density range (ca. 0-130 individuals dm -2 ), the relationship between adult density and recruit density (scaled to the available area for recruitment, which excluded adult barnacles) was unimodal. In years that exhibited a lower adult density range (ca. 0-40/50 individuals dm -2 ), the relationship between adult and recruit density was positive and resembled the lower half of the unimodal relationship. Overall, adult barnacle density was able to explain 26-40% of the observed variation in recruit density. The unimodal adult-recruit relationship is consistent with previously documented intraspecific interactions. Between low and intermediate adult densities, the positive nature of the relationship relates to the previously documented fact that settlement-seeking larvae are chemically and visually attracted to adults, which might be important for local population persistence. Between intermediate and high adult densities, where population persistence may be less compromised and the abundant adults may limit recruit growth and survival, the negative nature of the relationship suggests that adult barnacles at increasingly high densities stimulate larvae to settle elsewhere. The unimodal pattern may be especially common on shores with moderate rates of larval supply to the shore, because high rates of larval supply may swamp the coast with settlers, decoupling recruit density from local adult abundance.

Talbot-Lau x-ray deflectometry phase-retrieval methods for electron density diagnostics in high-energy density experiments.

PubMed

Valdivia, Maria Pia; Stutman, Dan; Stoeckl, Christian; Mileham, Chad; Begishev, Ildar A; Bromage, Jake; Regan, Sean P

2018-01-10

Talbot-Lau x-ray interferometry uses incoherent x-ray sources to measure refraction index changes in matter. These measurements can provide accurate electron density mapping through phase retrieval. An adaptation of the interferometer has been developed in order to meet the specific requirements of high-energy density experiments. This adaptation is known as a moiré deflectometer, which allows for single-shot capabilities in the form of interferometric fringe patterns. The moiré x-ray deflectometry technique requires a set of object and reference images in order to provide electron density maps, which can be costly in the high-energy density environment. In particular, synthetic reference phase images obtained ex situ through a phase-scan procedure, can provide a feasible solution. To test this procedure, an object phase map was retrieved from a single-shot moiré image obtained from a plasma-produced x-ray source. A reference phase map was then obtained from phase-stepping measurements using a continuous x-ray tube source in a small laboratory setting. The two phase maps were used to retrieve an electron density map. A comparison of the moiré and phase-stepping phase-retrieval methods was performed to evaluate single-exposure plasma electron density mapping for high-energy density and other transient plasma experiments. It was found that a combination of phase-retrieval methods can deliver accurate refraction angle mapping. Once x-ray backlighter quality is optimized, the ex situ method is expected to deliver electron density mapping with improved resolution. The steps necessary for improved diagnostic performance are discussed.

A single-walled carbon nanotubes/poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate)/copper hexacyanoferrate hybrid film for high-volumetric performance flexible supercapacitors

NASA Astrophysics Data System (ADS)

Li, Jianmin; Li, Haizeng; Li, Jiahui; Wu, Guiqing; Shao, Yuanlong; Li, Yaogang; Zhang, Qinghong; Wang, Hongzhi

2018-05-01

Volumetric energy density is generally considered to be detrimental to the actual application of supercapacitors, which has provoked a range of research work on increasing the packing density of electrodes. Herein, we fabricate a free-standing single-walled carbon nanotubes (SWCNTs)/poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS)/copper hexacyanoferrate (CuHCF) nanoparticles (NPs) composite supercapacitor electrode, with a high packing density of 2.67 g cm-3. The pseudocapacitive CuHCF NPs are decorated onto the SWCNTs/PEDOT:PSS networks and filled in interspace to increase both of packing density and specific capacitance. This hybrid electrode exhibits a series of outstanding performances, such as high electric conductivity, ultrahigh areal and volumetric capacitances (969.8 mF cm-2 and 775.2 F cm-3 at scan rate of 5 mV s-1), long cycle life and superior rate capability. The asymmetric supercapacitor built by using the SWCNTs/PEDOT:PSS/CuHCF film as positive electrode and Mo-doped WO3/SWCNTs film as negative electrode, can deliver a high energy density of 30.08 Wh L-1 with a power density of 4.25 kW L-1 based on the total volume of the device. The approach unveiled in this study could provide important insights to improving the volumetric performance of energy storage devices and help to reach the critical targets for high rate and high power density demand applications.

Diffusive dynamics during the high-to-low density transition in amorphous ice

DOE PAGES

Perakis, Fivos; Amann-Winkel, Katrin; Lehmkuhler, Felix; ...

2017-06-26

Water exists in high- and low-density amorphous ice forms (HDA and LDA), which could correspond to the glassy states of high- (HDL) and low-density liquid (LDL) in the metastable part of the phase diagram. However, the nature of both the glass transition and the high-to-low-density transition are debated and new experimental evidence is needed. Here we combine wide-angle X-ray scattering (WAXS) with X-ray photon-correlation spectroscopy (XPCS) in the small-angle X-ray scattering (SAXS) geometry to probe both the structural and dynamical properties during the high-to-low-density transition in amorphous ice at 1 bar. By analyzing the structure factor and the radial distributionmore » function, the coexistence of two structurally distinct domains is observed at T = 125 K. XPCS probes the dynamics in momentum space, which in the SAXS geometry reflects structural relaxation on the nanometer length scale. The dynamics of HDA are characterized by a slow component with a large time constant, arising from viscoelastic relaxation and stress release from nanometer-sized heterogeneities. Above 110 K a faster, strongly temperature-dependent component appears, with momentum transfer dependence pointing toward nanoscale diffusion. This dynamical component slows down after transition into the low-density form at 130 K, but remains diffusive. In conclusion, the diffusive character of both the high- and low-density forms is discussed among different interpretations and the results are most consistent with the hypothesis of a liquid–liquid transition in the ultraviscous regime.« less

Diffusive dynamics during the high-to-low density transition in amorphous ice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Perakis, Fivos; Amann-Winkel, Katrin; Lehmkuhler, Felix

Water exists in high- and low-density amorphous ice forms (HDA and LDA), which could correspond to the glassy states of high- (HDL) and low-density liquid (LDL) in the metastable part of the phase diagram. However, the nature of both the glass transition and the high-to-low-density transition are debated and new experimental evidence is needed. Here we combine wide-angle X-ray scattering (WAXS) with X-ray photon-correlation spectroscopy (XPCS) in the small-angle X-ray scattering (SAXS) geometry to probe both the structural and dynamical properties during the high-to-low-density transition in amorphous ice at 1 bar. By analyzing the structure factor and the radial distributionmore » function, the coexistence of two structurally distinct domains is observed at T = 125 K. XPCS probes the dynamics in momentum space, which in the SAXS geometry reflects structural relaxation on the nanometer length scale. The dynamics of HDA are characterized by a slow component with a large time constant, arising from viscoelastic relaxation and stress release from nanometer-sized heterogeneities. Above 110 K a faster, strongly temperature-dependent component appears, with momentum transfer dependence pointing toward nanoscale diffusion. This dynamical component slows down after transition into the low-density form at 130 K, but remains diffusive. In conclusion, the diffusive character of both the high- and low-density forms is discussed among different interpretations and the results are most consistent with the hypothesis of a liquid–liquid transition in the ultraviscous regime.« less

Diffusive dynamics during the high-to-low density transition in amorphous ice

NASA Astrophysics Data System (ADS)

Perakis, Fivos; Amann-Winkel, Katrin; Lehmkühler, Felix; Sprung, Michael; Mariedahl, Daniel; Sellberg, Jonas A.; Pathak, Harshad; Späh, Alexander; Cavalca, Filippo; Schlesinger, Daniel; Ricci, Alessandro; Jain, Avni; Massani, Bernhard; Aubree, Flora; Benmore, Chris J.; Loerting, Thomas; Grübel, Gerhard; Pettersson, Lars G. M.; Nilsson, Anders

2017-08-01

Water exists in high- and low-density amorphous ice forms (HDA and LDA), which could correspond to the glassy states of high- (HDL) and low-density liquid (LDL) in the metastable part of the phase diagram. However, the nature of both the glass transition and the high-to-low-density transition are debated and new experimental evidence is needed. Here we combine wide-angle X-ray scattering (WAXS) with X-ray photon-correlation spectroscopy (XPCS) in the small-angle X-ray scattering (SAXS) geometry to probe both the structural and dynamical properties during the high-to-low-density transition in amorphous ice at 1 bar. By analyzing the structure factor and the radial distribution function, the coexistence of two structurally distinct domains is observed at T = 125 K. XPCS probes the dynamics in momentum space, which in the SAXS geometry reflects structural relaxation on the nanometer length scale. The dynamics of HDA are characterized by a slow component with a large time constant, arising from viscoelastic relaxation and stress release from nanometer-sized heterogeneities. Above 110 K a faster, strongly temperature-dependent component appears, with momentum transfer dependence pointing toward nanoscale diffusion. This dynamical component slows down after transition into the low-density form at 130 K, but remains diffusive. The diffusive character of both the high- and low-density forms is discussed among different interpretations and the results are most consistent with the hypothesis of a liquid-liquid transition in the ultraviscous regime.

High performance all-solid-state symmetric supercapacitor based on porous carbon made from a metal-organic framework compound

NASA Astrophysics Data System (ADS)

Yu, Feng; Wang, Teng; Wen, Zubiao; Wang, Hongxia

2017-10-01

In this work, we demonstrate the synthesis of porous carbon material with high specific surface area by using metal-organic framework (MOF) as precursor. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) have confirmed that the material was amorphous and consisted of nanoparticles (5-6 nm) and hierarchical distribution of pores. The characterization of the material by N2 adsorption/desorption isotherm measurement have shown that the material had a high specific surface area reaching to 2618.7 m2 g-1 and abundant porosity with pore size less than 10 nm. The investigation of the electrochemical properties of the material has shown the porous carbon electrode possessed excellent rate performance with high specific capacitances of 150.8 F g-1 at a current density of 5 A g-1, and 133.6 F g-1 at a current density of 50 A g-1, respectively. An all-solid-state symmetric supercapacitor assembled using the as-prepared porous carbon as electrodes and Na2SO4/PVA gel as an electrolyte delivered a high power density of 13 516.4 W kg-1 with an energy density of 8.26 Wh kg-1. A high energy density of 17.37 Wh kg-1 was obtained at discharge current density of 1 A g-1. In addition, the device exhibited superior cycling performance with 94.8% retention rate after 10 000 cycles at a current density of 10 A g-1.

Soft magnetic characteristics of laminated magnetic block cores assembled with a high Bs nanocrystalline alloy

NASA Astrophysics Data System (ADS)

Yao, Atsushi; Inoue, Masaki; Tsukada, Kouhei; Fujisaki, Keisuke

2018-05-01

This paper focuses on an evaluation of core losses in laminated magnetic block cores assembled with a high Bs nanocrystalline alloy in high magnetic flux density region. To discuss the soft magnetic properties of the high Bs block cores, the comparison with amorphous (SA1) block cores is also performed. In the high Bs block core, both low core losses and high saturation flux densities Bs are satisfied in the low frequency region. Furthermore, in the laminated block core made of the high Bs alloy, the rate of increase of iron losses as a function of the magnetic flux density remains small up to around 1.6 T, which cannot be realized in conventional laminated block cores based on amorphous alloy. The block core made of the high Bs alloy exhibits comparable core loss with that of amorphous alloy core in the high-frequency region. Thus, it is expected that this laminated high Bs block core can achieve low core losses and high saturation flux densities in the high-frequency region.

Probing nuclear symmetry energy at high densities using pion, kaon, eta and photon productions in heavy-ion collisions

NASA Astrophysics Data System (ADS)

Xiao, Zhi-Gang; Yong, Gao-Chan; Chen, Lie-Wen; Li, Bao-An; Zhang, Ming; Xiao, Guo-Qing; Xu, Nu

2014-02-01

The high-density behavior of nuclear symmetry energy is among the most uncertain properties of dense neutron-rich matter. Its accurate determination has significant ramifications in understanding not only the reaction dynamics of heavy-ion reactions, especially those induced by radioactive beams, but also many interesting phenomena in astrophysics, such as the explosion mechanism of supernova and the properties of neutron stars. The heavy-ion physics community has devoted much effort during the last few years to constrain the high-density symmetry using various probes. In particular, the / ratio has been most extensively studied both theoretically and experimentally. All models have consistently predicted qualitatively that the / ratio is a sensitive probe of the high-density symmetry energy especially with beam energies near the pion production threshold. However, the predicted values of the / ratio are still quite model dependent mostly because of the complexity of modeling pion production and reabsorption dynamics in heavy-ion collisions, leading to currently still controversial conclusions regarding the high-density behavior of nuclear symmetry energy from comparing various model calculations with available experimental data. As more / data become available and a deeper understanding about the pion dynamics in heavy-ion reactions is obtained, more penetrating probes, such as the K +/ K 0 ratio, meson and high-energy photons are also being investigated or planned at several facilities. Here, we review some of our recent contributions to the community effort of constraining the high-density behavior of nuclear symmetry energy in heavy-ion collisions. In addition, the status of some worldwide experiments for studying the high-density symmetry energy, including the HIRFL-CSR external target experiment (CEE) are briefly introduced.

Enhancement of antioxidative activity and cardiovascular protection in hamsters by camellia oil and soybean-camellia blended oil.

PubMed

Chou, Ting-Yi; Lu, Yi-Fa; Inbaraj, Baskaran Stephen; Chen, Bing-Huei

2018-02-07

The aim of this study was to examine the effects of several vegetable oils and blended oil composed of soybean and camellia oils on blood lipid reduction and antioxidative activity. Forty male hamsters were fed an AIN-93 G diet for 1 wk, followed by dividing into five groups: control group-1 was fed a low-fat diet containing 5% oil for 6 wk, and the other four groups were fed high-fat diets with group-2 containing 14% palm oil, group-3 containing 14% camellia oil, group-4 containing 14% soybean oil, and group-5 containing 14% blended oil (8.4% soybean oil and 5.6% camellia oil) along with 0.2% cholesterol and 0.1% bile acid. High-fat diets raised serum triacylglycerol, total cholesterol, and aspartate aminotransferase in hamsters without affecting alanine aminotransferase. Compared with palm oil-containing diet, the other three high-fat diets reduced serum total cholesterol, low-density lipoprotein cholesterol, and the ratio of low-density lipoprotein to high-density lipoprotein cholesterol with an opposite trend for liver total cholesterol. However, compared with the control group, the serum high-density lipoprotein cholesterol level was raised for all four high-fat diets. The higher the degree of oil unsaturation, the higher the serum thiobarbituric acid reactive substances and the lower the liver triacylglycerol level and activities of fatty acid synthase, glucose 6-phosphate dehydrogenase, and malic enzymes. Both soybean and blended oils lowered the antioxidative activity of liver. Camellia and blended oils were more efficient than soybean oil in elevating serum high-density lipoprotein cholesterol and decreasing the ratio of low-density lipoprotein to high-density lipoprotein cholesterol in hamsters. Copyright © 2018 Elsevier Inc. All rights reserved.

Regulation of the seasonal population patterns of Helicoverpa armigera moths by Bt cotton planting.

PubMed

Gao, Yu-Lin; Feng, Hong-Qiang; Wu, Kong-Ming

2010-08-01

Transgenic cotton expressing the Bacillus thuringiensis (Bt) Cry1Ac toxin has been commercially cultivated in China since 1997, and by 2000 Bt cotton had almost completely replaced non-transgenic cotton cultivars. To evaluate the impact of Bt cotton planting on the seasonal population patterns of cotton bollworm, Helicoverpa armigera, the dynamics of H. armigera moths were monitored with light traps from four locations (Xiajin, Linqing and Dingtao of Shandong Province; Guantao of Hebei Province) in high Bt density region and five locations (Anci and Xinji of Hebei Province; Dancheng and Fengqiu of Henan Province; Gaomi of Shandong Province) in low Bt density region from 1996 to 2008. A negative correlation was found between moth densities of H. armigera and the planting years of Bt cotton in both high and low Bt density areas. These data indicate that the moth population density of H. armigera was reduced with the introduction of Bt cotton in northern China. Three generations of moths occurred between early June and late September in the cotton regions. Interestingly, second-generation moths decreased and seemed to vanish in recent years in high Bt density region, but this tendency was not found in low Bt density region. The data suggest that the planting of Bt cotton in high Bt density region was effective in controlling the population density of second-generation moths. Furthermore, the seasonal change of moth patterns associated with Bt cotton planting may regulate the regional occurrence and population development of this migratory insect.

Lipopolysaccharide effects on the proliferation of NRK52E cells via alternations in gap-junction function.

PubMed

Hei, Ziqing; Zhang, Ailan; Wei, Jing; Gan, Xiaoliang; Wang, Yanling; Luo, Gangjian; Li, Xiaoyun

2012-07-01

Gap junctions regulate proper kidney function by facilitating intercellular communication, vascular conduction, and tubular purinergic signaling. However, no clear relationship has been described between gap-junction function and acute kidney injury induced by the endotoxin lipopolysaccharide (LPS). Normal rat kidney epithelial cells (NRK52E cells) were seeded at high and low densities to promote or impede gap-junction formation, respectively, and establish distinctive levels of intercellular communication in culture. Cells were then challenged with LPS at various concentrations (10-1,000 ng/mL). LPS-induced formation and function of gap junctions were assessed by measuring changes in cell proliferation and colony-forming rates, fluorescent dye transmission to adjacent cells, expression levels of connexin43, and repositioning of confluent cells in response to the gap junction inhibitor oleamide or agonist retinoic acid. The cell proliferation rate and colony-forming rate of high- and low-density NRK52E cells were decreased upon LPS challenge, in a dose-dependent manner. The colony-forming rate of confluent high-density cells was significantly lower than that of low-density cells. Oleamide treatment raised the LPS-induced colony-forming rate of high-density cells, whereas retinoic acid decreased the rate. Neither oleamide nor retinoic acid significantly affected the LPS-induced colony-forming rate of low-density cells. Fluorescence transmission of high-density cells was reduced by LPS challenge, in a dose-dependent manner, but inclusion of retinoic acid increased the LPS-induced transmission of fluorescence. LPS challenge of either high- or low-density NRK52E cells resulted in down-regulated connexin43 expression. Gap-junction function plays an important role in concentration-dependent cytotoxic effect of LPS on normal rat kidney cells in vitro.

Effects of dietary live and heat-inactive baker's yeast on growth, gut health, and disease resistance of Nile tilapia under high rearing density.

PubMed

Ran, Chao; Huang, Lu; Hu, Jun; Tacon, Philippe; He, Suxu; Li, Zhimin; Wang, Yibing; Liu, Zhi; Xu, Li; Yang, Yalin; Zhou, Zhigang

2016-09-01

In this study, the effects of baker's yeast as probiotics was evaluated in Nile tilapia reared at high density. Juvenile tilapia were distributed to tanks at high density (436 fish/m(3)) and fed with basal diet (CK) or diets supplemented with live (LY) or heat-inactivated yeast (HIY). Another group of fish reared at low density (218 fish/m(3)) and fed with basal diet was also included (LowCK). After 8 weeks of feeding, growth, feed utilization, gut microvilli morphology, digestive enzymes, and expressions of hsp70 and inflammation-related cytokines in the intestine were assessed. Intestinal microbiota was investigated using 16S rRNA gene pyrosequencing. Fish were challenged with Aeromonas hydrophila to evaluate disease resistance. High rearing density significantly decreased the growth, feed utilization, microvilli length, and disease resistance of fish (CK versus LowCK). Moreover, the intestinal hsp70 expression was increased in fish reared at high density, supporting a stress condition. Compared to CK group, supplementation of live yeast significantly increased gut microvilli length and trypsin activity, decreased intestinal hsp70 expression, and enhanced resistance of fish against A. hydrophila (reflected by reduced intestinal alkaline phosphatase activity 24 h post infection). The gut microbiota was not markedly influenced by either rearing density or yeast supplementation. Heat-inactivated yeast (HIY) didn't display the beneficial effects observed in LY except an increase in gut trypsin activity, suggesting the importance of yeast viability and thus secretory metabolites of yeast. In conclusion, live baker's yeast may alleviate the negative effects induced by crowding stress, and has the potential to be used as probiotics for tilapia reared at high density. Copyright © 2016 Elsevier Ltd. All rights reserved.

Direct Laser Writing of Low-Density Interdigitated Foams for Plasma Drive Shaping [Direct Laser Writing of Low Density Nanostitched Foams for Plasma Drive Shaping

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oakdale, James S.; Smith, Raymond F.; Forien, Jean -Baptiste

Monolithic porous bulk materials have many promising applications ranging from energy storage and catalysis to high energy density physics. High resolution additive manufacturing techniques, such as direct laser writing via two photon polymerization (DLW-TPP), now enable the fabrication of highly porous microlattices with deterministic morphology control. In this work, DLW-TPP is used to print millimeter-sized foam reservoirs (down to 0.06 g cm –3) with tailored density-gradient profiles, where density is varied by over an order of magnitude (for instance from 0.6 to 0.06 g cm –3) along a length of <100 µm. Taking full advantage of this technology, however, ismore » a multiscale materials design problem that requires detailed understanding of how the different length scales, from the molecular level to the macroscopic dimensions, affect each other. The design of these 3D-printed foams is based on the brickwork arrangement of 100 × 100 × 16 µm 3 log-pile blocks constructed from sub-micrometer scale features. A block-to-block interdigitated stitching strategy is introduced for obtaining high density uniformity at all length scales. Lastly, these materials are used to shape plasma-piston drives during ramp-compression of targets under high energy density conditions created at the OMEGA Laser Facility.« less

Direct Laser Writing of Low-Density Interdigitated Foams for Plasma Drive Shaping [Direct Laser Writing of Low Density Nanostitched Foams for Plasma Drive Shaping

DOE PAGES

Oakdale, James S.; Smith, Raymond F.; Forien, Jean -Baptiste; ...

2017-09-27

Monolithic porous bulk materials have many promising applications ranging from energy storage and catalysis to high energy density physics. High resolution additive manufacturing techniques, such as direct laser writing via two photon polymerization (DLW-TPP), now enable the fabrication of highly porous microlattices with deterministic morphology control. In this work, DLW-TPP is used to print millimeter-sized foam reservoirs (down to 0.06 g cm –3) with tailored density-gradient profiles, where density is varied by over an order of magnitude (for instance from 0.6 to 0.06 g cm –3) along a length of <100 µm. Taking full advantage of this technology, however, ismore » a multiscale materials design problem that requires detailed understanding of how the different length scales, from the molecular level to the macroscopic dimensions, affect each other. The design of these 3D-printed foams is based on the brickwork arrangement of 100 × 100 × 16 µm 3 log-pile blocks constructed from sub-micrometer scale features. A block-to-block interdigitated stitching strategy is introduced for obtaining high density uniformity at all length scales. Lastly, these materials are used to shape plasma-piston drives during ramp-compression of targets under high energy density conditions created at the OMEGA Laser Facility.« less

High quality InP-on-Si for solar cell applications

NASA Technical Reports Server (NTRS)

Shellenbarger, Zane A.; Goodwin, Thomas A.; Collins, Sandra R.; Dinetta, Louis C.

1994-01-01

InP on Si solar cells combine the low-cost and high-strength of Si with the high efficiency and radiation tolerance of InP. The main obstacle in the growth of single crystal InP-on-Si is the high residual strain and high dislocation density of the heteroepitaxial InP films. The dislocations result from the large differences in lattice constant and thermal expansion mismatch of InP and Si. Adjusting the size and geometry of the growth area is one possible method of addressing this problem. In this work, we conducted a material quality study of liquid phase epitaxy overgrowth layers on selective area InP grown by a proprietary vapor phase epitaxy technique on Si. The relationship between growth area and dislocation density was quantified using etch pit density measurements. Material quality of the InP on Si improved both with reduced growth area and increased aspect ratio (length/width) of the selective area. Areas with etch pit density as low as 1.6 x 10(exp 4) sq cm were obtained. Assuming dislocation density is an order of magnitude greater than etch pit density, solar cells made with this material could achieve the maximum theoretical efficiency of 23% at AMO. Etch pit density dependence on the orientation of the selective areas on the substrate was also studied.

Molecular design and property prediction of high density polynitro[3.3.3]-propellane-derivatized frameworks as potential high explosives.

PubMed

Zhang, Qinghua; Zhang, Jiaheng; Qi, Xiujuan; Shreeve, Jean'ne M

2014-11-13

Research in energetic materials is now heavily focused on the design and synthesis of novel insensitive high explosives (IHEs) for specialized applications. As an effective and time-saving tool for screening potential explosive structures, computer simulation has been widely used for the prediction of detonation properties of energetic molecules with relatively high precision. In this work, a series of new polynitrotetraoxopentaaza[3.3.3]-propellane molecules with tricyclic structures were designed. Their properties as potential high explosives including density, heats of formation, detonation properties, impact sensitivity, etc., have been extensively evaluated using volume-based thermodynamic calculations and density functional theory (DFT).These new energetic molecules exhibit high densities of >1.82 g cm(-3), in which 1 gives the highest density of 2.04 g cm(-3). Moreover, most new materials show good detonation properties and acceptable impact sensitivities, in which 5 displays much higher detonation velocity (9482 m s(-1)) and pressure (43.9 GPa) than HMX and has a h50 value of 11 cm. These results are expected to facilitate the experimental synthesis of new-generation nitramine-based high explosives.

Genome-wide association studies identified novel loci for non-high-density lipoprotein cholesterol and its postprandial lipemic response

USDA-ARS?s Scientific Manuscript database

Non-high-density lipoprotein cholesterol (NHDL) is an independent and superior predictor of CVD risk as compared to low-density lipoprotein alone. It represents a spectrum of atherogenic lipid fractions with possibly a distinct genomic signature. We performed genome-wide association studies (GWAS) t...

High-energy side-peak emission of exciton-polariton condensates in high density regime

PubMed Central

Horikiri, Tomoyuki; Yamaguchi, Makoto; Kamide, Kenji; Matsuo, Yasuhiro; Byrnes, Tim; Ishida, Natsuko; Löffler, Andreas; Höfling, Sven; Shikano, Yutaka; Ogawa, Tetsuo; Forchel, Alfred; Yamamoto, Yoshihisa

2016-01-01

In a standard semiconductor laser, electrons and holes recombine via stimulated emission to emit coherent light, in a process that is far from thermal equilibrium. Exciton-polariton condensates–sharing the same basic device structure as a semiconductor laser, consisting of quantum wells coupled to a microcavity–have been investigated primarily at densities far below the Mott density for signatures of Bose-Einstein condensation. At high densities approaching the Mott density, exciton-polariton condensates are generally thought to revert to a standard semiconductor laser, with the loss of strong coupling. Here, we report the observation of a photoluminescence sideband at high densities that cannot be accounted for by conventional semiconductor lasing. This also differs from an upper-polariton peak by the observation of the excitation power dependence in the peak-energy separation. Our interpretation as a persistent coherent electron-hole-photon coupling captures several features of this sideband, although a complete understanding of the experimental data is lacking. A full understanding of the observations should lead to a development in non-equilibrium many-body physics. PMID:27193700

Supercapacitors based on self-assembled graphene organogel.

PubMed

Sun, Yiqing; Wu, Qiong; Shi, Gaoquan

2011-10-14

Self-assembled graphene organogel (SGO) with 3-dimensional (3D) macrostructure was prepared by solvothermal reduction of a graphene oxide (GO) dispersion in propylene carbonate (PC). This SGO was used as an electrode material for fabricating supercapacitors with a PC electrolyte. The supercapacitor can be operated in a wide voltage range of 0-3 V and exhibits a high specific capacitance of 140 F g(-1) at a discharge current density of 1 A g(-1). Furthermore, it can still keep a specific capacitance of 90 F g(-1) at a high current density of 30 A g(-1). The maximum energy density of the SGO based supercapacitor was tested to be 43.5 Wh kg(-1), and this value is higher than those of the graphene based supercapacitors with aqueous or PC electrolytes reported previously. Furthermore, at a high discharge current density of 30 A g(-1), the energy and power densities of the supercapacitor were measured to be 15.4 Wh kg(-1) and 16,300 W kg(-1), respectively. These results indicate that the supercapacitor has a high specific capacitance and power density, and excellent rate capability.

Spatial Patterns of Plasmodium falciparum Clinical Incidence, Asymptomatic Parasite Carriage and Anopheles Density in Two Villages in Mali

PubMed Central

Sissoko, Mahamadou S.; van den Hoogen, Lotus L.; Samake, Yacouba; Tapily, Amadou; Diarra, Adama Z.; Coulibaly, Maimouna; Bouare, Madama; Gaudart, Jean; Knight, Philip; Sauerwein, Robert W.; Takken, Willem; Bousema, Teun; Doumbo, Ogobara K.

2015-01-01

Heterogeneity in malaria exposure is most readily recognized in areas with low-transmission patterns. By comparison, little research has been done on spatial patterns in malaria exposure in high-endemic settings. We determined the spatial clustering of clinical malaria incidence, asymptomatic parasite carriage, and Anopheles density in two villages in Mali exposed to low- and mesoendemic-malaria transmission. In the two study areas that were < 1 km2 in size, we observed evidence for spatial clustering of Anopheles densities or malaria parasite carriage during the dry season. Anopheles density and malaria prevalence appeared associated in some of our detected hotspots. However, many households with high parasite prevalence or high Anopheles densities were located outside the identified hotspots. Our findings indicate that within small villages exposed to low- or mesoendemic-malaria transmission, spatial patterns in mosquito densities and parasite carriage are best detected in the dry season. Considering the high prevalence of parasite carriage outside detected hotspots, the suitability of the area for targeting control efforts to households or areas of more intense malaria transmission may be limited. PMID:26324728

Neutral-depletion-induced axially asymmetric density in a helicon source and imparted thrust

NASA Astrophysics Data System (ADS)

Takahashi, Kazunori; Takao, Yoshinori; Ando, Akira

2016-02-01

The high plasma density downstream of the source is observed to be sustained only for a few hundreds of microsecond at the initial phase of the discharge, when pulsing the radiofrequency power of a helicon plasma thruster. Measured relative density of argon neutrals inside the source implies that the neutrals are significantly depleted there. A position giving a maximum plasma density temporally moves to the upstream side of the source due to the neutral depletion and then the exhausted plasma density significantly decreases. The direct thrust measurement demonstrates that the higher thrust-to-power ratio is obtained by using only the initial phase of the high density plasma, compared with the steady-state operation.

Crumpled Nitrogen-Doped Graphene for Supercapacitors with High Gravimetric and Volumetric Performances.

PubMed

Wang, Jie; Ding, Bing; Xu, Yunling; Shen, Laifa; Dou, Hui; Zhang, Xiaogang

2015-10-14

Graphene is considered a promising electrochemical capacitors electrode material due to its high surface area and high electrical conductivity. However, restacking interactions between graphene nanosheets significantly decrease the ion-accessible surface area and impede electronic and ionic transfer. This would, in turn, severely hinder the realization of high energy density. Herein, we report a strategy for preparation of few-layer graphene material with abundant crumples and high-level nitrogen doping. The two-dimensional graphene nanosheets (CNG) feature high ion-available surface area, excellent electronic and ion transfer properties, and high packing density, permitting the CNG electrode to exhibit excellent electrochemical performance. In ionic liquid electrolyte, the CNG electrode exhibits gravimetric and volumetric capacitances of 128 F g(-1) and 98 F cm(-3), respectively, achieving gravimetric and volumetric energy densities of 56 Wh kg(-1) and 43 Wh L(-1). The preparation strategy described here provides a new approach for developing a graphene-based supercapacitor with high gravimetric and volumetric energy densities.

Hybrid system for rechargeable magnesium battery with high energy density

PubMed Central

Chang, Zheng; Yang, Yaqiong; Wang, Xiaowei; Li, Minxia; Fu, Zhengwen; Wu, Yuping; Holze, Rudolf

2015-01-01

One of the main challenges of electrical energy storage (EES) is the development of environmentally friendly battery systems with high safety and high energy density. Rechargeable Mg batteries have been long considered as one highly promising system due to the use of low cost and dendrite-free magnesium metal. The bottleneck for traditional Mg batteries is to achieve high energy density since their output voltage is below 2.0 V. Here, we report a magnesium battery using Mg in Grignard reagent-based electrolyte as the negative electrode, a lithium intercalation compound in aqueous solution as the positive electrode, and a solid electrolyte as a separator. Its average discharge voltage is 2.1 V with stable discharge platform and good cycling life. The calculated energy density based on the two electrodes is high. These findings open another door to rechargeable magnesium batteries. PMID:26173624

1 μm-thickness ultra-flexible and high electrode-density surface electromyogram measurement sheet with 2 V organic transistors for prosthetic hand control.

PubMed

Fuketa, Hiroshi; Yoshioka, Kazuaki; Shinozuka, Yasuhiro; Ishida, Koichi; Yokota, Tomoyuki; Matsuhisa, Naoji; Inoue, Yusuke; Sekino, Masaki; Sekitani, Tsuyoshi; Takamiya, Makoto; Someya, Takao; Sakurai, Takayasu

2014-12-01

A 64-channel surface electromyogram (EMG) measurement sheet (SEMS) with 2 V organic transistors on a 1 μm-thick ultra-flexible polyethylene naphthalate (PEN) film is developed for prosthetic hand control. The surface EMG electrodes must satisfy the following three requirements; high mechanical flexibility, high electrode density and high signal integrity. To achieve high electrode density and high signal integrity, a distributed and shared amplifier (DSA) architecture is proposed, which enables an in-situ amplification of the myoelectric signal with a fourfold increase in EMG electrode density. In addition, a post-fabrication select-and-connect (SAC) method is proposed to cope with the large mismatch of organic transistors. The proposed SAC method reduces the area and the power overhead by 96% and 98.2%, respectively, compared with the use of conventional parallel transistors to reduce the transistor mismatch by a factor of 10.

High population density enhances recruitment and survival of a harvested coral reef fish.

PubMed

Wormald, Clare L; Steele, Mark A; Forrester, Graham E

2013-03-01

A negative relationship between population growth and population density (direct density dependence) is necessary for population regulation and is assumed in most models of harvested populations. Experimental tests for density dependence are lacking for large-bodied, harvested fish because of the difficulty of manipulating population density over large areas. We studied a harvested coral reef fish, Lutjanus apodus (schoolmaster snapper), using eight large, isolated natural reefs (0.4-1.6 ha) in the Bahamas as replicates. An initial observational test for density dependence was followed by a manipulation of population density. The manipulation weakened an association between density and shelter-providing habitat features and revealed a positive effect of population density on recruitment and survival (inverse density dependence), but no effect of density on somatic growth. The snappers on an individual reef were organized into a few shoals, and we hypothesize that large shoals on high-density reefs were less vulnerable to large piscivores (groupers and barracudas) than the small shoals on low-density reefs. Reductions in predation risk for individuals in large social groups are well documented, but because snapper shoals occupied reefs the size of small marine reserves, these ecological interactions may influence the outcome of management actions.

Genetic structure, spatial organization, and dispersal in two populations of bat-eared foxes

PubMed Central

Kamler, Jan F; Gray, Melissa M; Oh, Annie; Macdonald, David W

2013-01-01

We incorporated radio-telemetry data with genetic analysis of bat-eared foxes (Otocyon megalotis) from individuals in 32 different groups to examine relatedness and spatial organization in two populations in South Africa that differed in density, home-range sizes, and group sizes. Kin clustering occurred only for female dyads in the high-density population. Relatedness was negatively correlated with distance only for female dyads in the high-density population, and for male and mixed-sex dyads in the low-density population. Home-range overlap of neighboring female dyads was significantly greater in the high compared to low-density population, whereas overlap within other dyads was similar between populations. Amount of home-range overlap between neighbors was positively correlated with genetic relatedness for all dyad-site combinations, except for female and male dyads in the low-density population. Foxes from all age and sex classes dispersed, although females (mostly adults) dispersed farther than males. Yearlings dispersed later in the high-density population, and overall exhibited a male-biased dispersal pattern. Our results indicated that genetic structure within populations of bat-eared foxes was sex-biased, and was interrelated to density and group sizes, as well as sex-biases in philopatry and dispersal distances. We conclude that a combination of male-biased dispersal rates, adult dispersals, and sex-biased dispersal distances likely helped to facilitate inbreeding avoidance in this evolutionarily unique species of Canidae. PMID:24101981

A stencil printed, high energy density silver oxide battery using a novel photopolymerizable poly(acrylic acid) separator.

PubMed

Braam, Kyle; Subramanian, Vivek

2015-01-27

A novel photopolymerized poly(acrylic acid) separator is demonstrated in a printed, high-energy-density silver oxide battery. The printed battery demonstrates a high capacity of 5.4 mA h cm(-2) at a discharge current density of 2.75 mA cm(-2) (C/2 rate) while delivering good mechanical flexibility and robustness. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Interpreting Multiple Logistic Regression Coefficients in Prospective Observational Studies

DTIC Science & Technology

1982-11-01

TG HDL -C Males T-C 50-80 MRW pɘ.05 pɘ.10 1HDL-C = high density lipoprotein cholesterol MRW...consider a more complete analy- sis, attempting to uncover the relationship between CHD and TG controlling for covariables such a high density ...for T-C can be re- duced, when among older individuals, elevated T-C may increase the capacity to carry cholesterol in the high density lipoprotein

Operation Everest II. Plasma Lipid and Hormonal Responses

DTIC Science & Technology

1988-01-01

cholesterol [TC] and high density lipoprotein cholesterol [ HDL -C] concentrations are shown in Fig 2. Pre-ascent...of altitude on fasting total cholesterol and high density lipoprotein ( HDL ) cholesterol concentrations. ** = p<O.Ol from 760 Torr Figure 3: The effect...157.7*9.7 mg/dl, decreased by 25% to .6 118.3*13.5 mg/dl following the 40-day exposure (p<O.Ol). High density lipoprotein [ HDL -C] levels

Fifth International Conference on High Energy Density Physics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beg, Farhat

The Fifth International Conference on High Energy Density Physics (ICHED 2015) was held in the Catamaran Hotel in San Diego from August 23-27, 2015. This meeting was the fifth in a series which began in 2008 in conjunction with the April meeting of the American Physical Society (APS). The main goal of this conference has been to bring together researchers from all fields of High Energy Density Science (HEDS) into one, unified meeting.

A High Density Electrophysiological Data Analysis System for a Peripheral Nerve Interface Communicating with Individual Neurons in the Brain

DTIC Science & Technology

2016-11-14

necessary capability to build a high density communication highway between 86 billion brain neurons and intelligent vehicles or robots . With this...build a high density communication highway between brain neurons and intelligent vehicles or robots . The final outcome of the INI using TDT system...will be beneficial to wounded warriors suffering from loss of limb function, so that, using sophisticated bidirectional robotic limbs, these

High power density dc/dc converter: Component selection and design

NASA Technical Reports Server (NTRS)

Divan, Deepakraj M.

1989-01-01

Further work pertaining to design considerations for the new high power, high frequency dc/dc converters is discussed. The goal of the project is the development of high power, high power density dc/dc converters at power levels in the multi-kilowatt to megawatt range for aerospace applications. The prototype converter is rated for 50 kW at a switching frequency of 50 kHz, with an input voltage of 200 Vdc and an output of 2000 Vdc. The overall power density must be in the vicinity of 0.2 to 0.3 kg/kW.

SiN sub x passivation of silicon surfaces

NASA Technical Reports Server (NTRS)

Olsen, L. C.

1986-01-01

The objectives were to perform surface characterization of high efficiency n+/p and p+/n silicon cells, to relate surface density to substrate dopant concentration, and to identify dominant current loss mechanisms in high efficiency cells. The approach was to measure density of states on homogeneously doped substrates with high frequency C-V and Al/SiN sub x/Si structures; to investigate density of states and photoresponse of high efficiency N+/P and P+/N cells; and to conduct I-V-T studies to identify current loss nechanisms in high efficiency cells. Results are given in tables and graphs.

Collagen Matrix Density Drives the Metabolic Shift in Breast Cancer Cells.

PubMed

Morris, Brett A; Burkel, Brian; Ponik, Suzanne M; Fan, Jing; Condeelis, John S; Aguirre-Ghiso, Julio A; Castracane, James; Denu, John M; Keely, Patricia J

2016-11-01

Increased breast density attributed to collagen I deposition is associated with a 4-6 fold increased risk of developing breast cancer. Here, we assessed cellular metabolic reprogramming of mammary carcinoma cells in response to increased collagen matrix density using an in vitro 3D model. Our initial observations demonstrated changes in functional metabolism in both normal mammary epithelial cells and mammary carcinoma cells in response to changes in matrix density. Further, mammary carcinoma cells grown in high density collagen matrices displayed decreased oxygen consumption and glucose metabolism via the tricarboxylic acid (TCA) cycle compared to cells cultured in low density matrices. Despite decreased glucose entry into the TCA cycle, levels of glucose uptake, cell viability, and ROS were not different between high and low density matrices. Interestingly, under high density conditions the contribution of glutamine as a fuel source to drive the TCA cycle was significantly enhanced. These alterations in functional metabolism mirrored significant changes in the expression of metabolic genes involved in glycolysis, oxidative phosphorylation, and the serine synthesis pathway. This study highlights the broad importance of the collagen microenvironment to cellular expression profiles, and shows that changes in density of the collagen microenvironment can modulate metabolic shifts of cancer cells. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Growth and wood/bark properties of Abies faxoniana seedlings as affected by elevated CO2.

PubMed

Qiao, Yun-Zhou; Zhang, Yuan-Bin; Wang, Kai-Yun; Wang, Qian; Tian, Qi-Zhuo

2008-03-01

Growth and wood and bark properties of Abies faxoniana seedlings after one year's exposure to elevated CO2 concentration (ambient + 350 (+/- 25) micromol/mol) under two planting densities (28 or 84 plants/m(2)) were investigated in closed-top chambers. Tree height, stem diameter and cross-sectional area, and total biomass were enhanced under elevated CO2 concentration, and reduced under high planting density. Most traits of stem bark were improved under elevated CO2 concentration and reduced under high planting density. Stem wood production was significantly increased in volume under elevated CO2 concentration under both densities, and the stem wood density decreased under elevated CO2 concentration and increased under high planting density. These results suggest that the response of stem wood and bark to elevated CO2 concentration is density dependent. This may be of great importance in a future CO2 enriched world in natural forests where plant density varies considerably. The results also show that the bark/wood ratio in diameter, stem cross-sectional area and dry weight are not proportionally affected by elevated CO2 concentration under the two contrasting planting densities. This indicates that the response magnitude of stem bark and stem wood to elevated CO2 concentration are different but their response directions are the same.

Sensitivity of condition indices to changing density in a white-tailed deer population

USGS Publications Warehouse

Sams, M.G.; Lochmiller, R.L.; Qualls, C.W.; Leslie, David M.

1998-01-01

The ways in which comprehensive condition profiles, incorporating morphometric, histologic, physiologic, and diet quality indices, responded to changes in density of a white-tailed deer (Odocoileus virginianus) population were examined. Changes in these condition indices were monitored in a northeastern Oklahoma deer herd as density declined from peaks of 80 and 72 deer/km2 in 1989 and 1990 (high-density) to lows of 39 and 41 deer/km2 in 1991 and 1992 (reduced-density), respectively. Compared to a reference population (6 deer/km2), deer sampled during high-density exhibited classic signs of nutritional stress such as low body and visceral organ masses (except elevated adrenal gland mass), low fecal nitrogen levels, reduced concentrations of serum albumin, elevated serum creatinine concentrations, and a high prevalence of parasitic infections. Although density declined by one half over the 4-yr study, gross indices of condition (in particular body mass and size) remained largely unchanged. However, selected organ masses, serum albumin and non-protein nitrogen constituents, and fecal nitrogen indices reflected improvements in nutritional status with reductions in density. Many commonly used indices of deer condition (fat reserves, hematocrit, total serum protein, and blood urea nitrogen) were not responsive to fluctuations in density. ?? Wildlife Disease Association 1998.

Neighbourhood density and genetic relatedness interact to determine fruit set and abortion rates in a continuous tropical tree population

PubMed Central

Jones, F.A; Comita, L.S

2008-01-01

Tropical trees may show positive density dependence in fruit set and maturation due to pollen limitation in low-density populations. However, pollen from closely related individuals in the local neighbourhood might reduce fruit set or increase fruit abortion in self-incompatible tree species. We investigated the role of neighbourhood density and genetic relatedness on individual fruit set and abortion in the neotropical tree Jacaranda copaia in a large forest plot in central Panama. Using nested neighbourhood models, we found a strong positive effect of increased conspecific density on fruit set and maturation. However, high neighbourhood genetic relatedness interacted with density to reduce total fruit set and increase the proportion of aborted fruit. Our results imply a fitness advantage for individuals growing in high densities as measured by fruit set, but realized fruit set is lowered by increased neighbourhood relatedness. We hypothesize that the mechanism involved is increased visitation by density-dependent invertebrate pollinators in high-density populations, which increases pollen quantity and carry-over and increases fruit set and maturation, coupled with self-incompatibility at early and late stages due to biparental inbreeding that lowers fruit set and increases fruit abortion. Implications for the reproductive ecology and conservation of tropical tree communities in continuous and fragmented habitats are discussed. PMID:18713714

FALCON: fast and unbiased reconstruction of high-density super-resolution microscopy data

NASA Astrophysics Data System (ADS)

Min, Junhong; Vonesch, Cédric; Kirshner, Hagai; Carlini, Lina; Olivier, Nicolas; Holden, Seamus; Manley, Suliana; Ye, Jong Chul; Unser, Michael

2014-04-01

Super resolution microscopy such as STORM and (F)PALM is now a well known method for biological studies at the nanometer scale. However, conventional imaging schemes based on sparse activation of photo-switchable fluorescent probes have inherently slow temporal resolution which is a serious limitation when investigating live-cell dynamics. Here, we present an algorithm for high-density super-resolution microscopy which combines a sparsity-promoting formulation with a Taylor series approximation of the PSF. Our algorithm is designed to provide unbiased localization on continuous space and high recall rates for high-density imaging, and to have orders-of-magnitude shorter run times compared to previous high-density algorithms. We validated our algorithm on both simulated and experimental data, and demonstrated live-cell imaging with temporal resolution of 2.5 seconds by recovering fast ER dynamics.

FALCON: fast and unbiased reconstruction of high-density super-resolution microscopy data

PubMed Central

Min, Junhong; Vonesch, Cédric; Kirshner, Hagai; Carlini, Lina; Olivier, Nicolas; Holden, Seamus; Manley, Suliana; Ye, Jong Chul; Unser, Michael

2014-01-01

Super resolution microscopy such as STORM and (F)PALM is now a well known method for biological studies at the nanometer scale. However, conventional imaging schemes based on sparse activation of photo-switchable fluorescent probes have inherently slow temporal resolution which is a serious limitation when investigating live-cell dynamics. Here, we present an algorithm for high-density super-resolution microscopy which combines a sparsity-promoting formulation with a Taylor series approximation of the PSF. Our algorithm is designed to provide unbiased localization on continuous space and high recall rates for high-density imaging, and to have orders-of-magnitude shorter run times compared to previous high-density algorithms. We validated our algorithm on both simulated and experimental data, and demonstrated live-cell imaging with temporal resolution of 2.5 seconds by recovering fast ER dynamics. PMID:24694686

Engineering of a hybrid nanoparticle-based nicotine nanovaccine as a next-generation immunotherapeutic strategy against nicotine addiction: A focus on hapten density.

PubMed

Zhao, Zongmin; Powers, Kristen; Hu, Yun; Raleigh, Michael; Pentel, Paul; Zhang, Chenming

2017-04-01

Although vaccination is a promising way to combat nicotine addiction, most traditional hapten-protein conjugate nicotine vaccines only show limited efficacy due to their poor recognition and uptake by immune cells. This study aimed to develop a hybrid nanoparticle-based nicotine vaccine with improved efficacy. The focus was to study the impact of hapten density on the immunological efficacy of the proposed hybrid nanovaccine. It was shown that the nanovaccine nanoparticles were taken up by the dendritic cells more efficiently than the conjugate vaccine, regardless of the hapten density on the nanoparticles. At a similar hapten density, the nanovaccine induced a significantly stronger immune response against nicotine than the conjugate vaccine in mice. Moreover, the high- and medium-density nanovaccines resulted in significantly higher anti-nicotine antibody titers than their low-density counterpart. Specifically, the high-density nanovaccine exhibited better immunogenic efficacy, resulting in higher anti-nicotine antibody titers and lower anti-carrier protein antibody titers than the medium- and low-density versions. The high-density nanovaccine also had the best ability to retain nicotine in serum and to block nicotine from entering the brain. These results suggest that the hybrid nanoparticle-based nicotine vaccine can elicit strong immunogenicity by modulating the hapten density, thereby providing a promising next-generation immunotherapeutic strategy against nicotine addiction. Copyright © 2017 Elsevier Ltd. All rights reserved.