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  • 1
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    PANGAEA
    In:  Supplement to: Clough, Lisa; Ambrose, William G Jr; Cochran, James R; Barnes, C; Renaud, Paul E; Aller, Robert C (1997): Infaunal density, biomass and bioturbation in the sediments of the Arctic Ocean. Deep Sea Research Part II: Topical Studies in Oceanography, 44(8), 1683-1704, https://doi.org/10.1016/S0967-0645(97)00052-0
    Publication Date: 2023-09-19
    Description: Little is known about the benthic communities of the Arctic Ocean's slope and abyssal plains. Here we report on benthic data collected from box cores along a transect from Alaska to the Barents Abyssal Plain during the Arctic Ocean Section of 1994. We determined: (1) density and biomass of the polychaetes, foraminifera and total infauna; (2) concentrations of potential sources of food (pigment concentration and percent organic carbon) in the sediments; (3) surficial particle mixing depths and rates using downcore 210Pb profiles; and (4) surficial porewater irrigation using NaBr as an inert tracer. Metazoan density and biomass vary by almost three orders of magnitude from the shelf to the deep basins (e.g. 47 403 individuals m**-2 on the Chukchi Shelf to 95 individuals m**-2 in the Barents Abyssal Plain). Water depth is the primary determinant of infaunal density, explaining 39% of the total variability. Potential food concentration varies by almost two orders of magnitude during the late summer season (e.g. the phaeopigment concentration integrated to 10 cm varies from 36.16 mg m**-2 on the Chukchi Shelf to 0.94 mg m**-2 in the Siberia Abyssal Plain) but is not significantly correlated with density or biomass of the metazoa. Most stations show evidence of particle mixing, with mixing limited to 〈=3 cm below the sediment-water interface, and enhanced pore water irrigation occurs at seven of the nine stations examined. Particle mixing depths may be related to metazoan biomass, while enhanced pore water irrigation (beyond what is expected from diffusion alone) appears to be related to total phaeopigment concentration. The data presented here indicate that Arctic benthic ecosystems are quite variable, but all stations sampled contained infauna and most stations had indications of active processing of the sediment by the associated infauna.
    Keywords: ADEPD; ADEPDCruises; AOS94_1; AOS94_12; AOS94_13; AOS94_16; AOS94_17; AOS94_19; AOS94_21; AOS94_23; AOS94_24; AOS94_25; AOS94_26; AOS94_28; AOS94_30; AOS94_31; AOS94_32; AOS94_33; AOS94_6; AOS94_7; AOS94_8; Arlis Plateau; Atlantic Data Base for Exchange Processes at the Deep Sea Floor; Barents abyssal plain; BC; Box corer; Chukchi Abyssal Plain; Chukchi shelf; Chukchi solpe; Lomonosov Ridge, Arctic Ocean; Mendeleev Ridge, Arctic Ocean; Mendeleev slope; North Pole; Siberia Abyssal Plain; Wrangel Abyssal Plain
    Type: Dataset
    Format: application/zip, 3 datasets
    Location Call Number Limitation Availability
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  • 2
    Publication Date: 2023-09-19
    Keywords: ADEPD; ADEPDCruises; AOS94_1; AOS94_13; AOS94_16; AOS94_17; AOS94_19; AOS94_21; AOS94_23; AOS94_24; AOS94_25; AOS94_26; AOS94_28; AOS94_30; AOS94_31; AOS94_32; AOS94_33; AOS94_6; AOS94_7; AOS94_8; Arlis Plateau; Atlantic Data Base for Exchange Processes at the Deep Sea Floor; Barents abyssal plain; BC; Box corer; Chukchi Abyssal Plain; Chukchi shelf; Chukchi solpe; DEPTH, sediment/rock; Elevation of event; Event label; Latitude of event; Lomonosov Ridge, Arctic Ocean; Longitude of event; Mendeleev Ridge, Arctic Ocean; Mendeleev slope; Mixing, enhanced irrigation; Mixing depth; Mixing rate; Mode, grain size; North Pole; Porosity; Siberia Abyssal Plain; Wrangel Abyssal Plain
    Type: Dataset
    Format: text/tab-separated-values, 83 data points
    Location Call Number Limitation Availability
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  • 3
    Publication Date: 2023-09-19
    Keywords: ADEPD; ADEPDCruises; AOS94_1; AOS94_12; AOS94_13; AOS94_16; AOS94_17; AOS94_19; AOS94_21; AOS94_23; AOS94_24; AOS94_25; AOS94_26; AOS94_28; AOS94_30; AOS94_31; AOS94_32; AOS94_33; AOS94_6; AOS94_7; AOS94_8; Arlis Plateau; Atlantic Data Base for Exchange Processes at the Deep Sea Floor; Barents abyssal plain; BC; Box corer; Chukchi Abyssal Plain; Chukchi shelf; Chukchi solpe; Counting 〉250 µm fraction; DEPTH, sediment/rock; Event label; Foraminifera, benthic; Foraminifera, benthic, biomass as carbon; Infauna; Infauna, biomass as carbon; Lomonosov Ridge, Arctic Ocean; Meiofauna, abundance of metazoa; Meiofauna, metazoa, biomass as carbon; Mendeleev Ridge, Arctic Ocean; Mendeleev slope; North Pole; Polychaeta; Polychaeta, biomass as carbon; Siberia Abyssal Plain; Wrangel Abyssal Plain
    Type: Dataset
    Format: text/tab-separated-values, 150 data points
    Location Call Number Limitation Availability
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  • 4
    Publication Date: 2024-01-08
    Keywords: ADEPD; ADEPDCruises; AOS94_1; AOS94_12; AOS94_13; AOS94_16; AOS94_17; AOS94_19; AOS94_21; AOS94_23; AOS94_24; AOS94_25; AOS94_26; AOS94_28; AOS94_30; AOS94_31; AOS94_32; AOS94_33; AOS94_6; AOS94_7; AOS94_8; Arlis Plateau; Atlantic Data Base for Exchange Processes at the Deep Sea Floor; Barents abyssal plain; BC; Box corer; Calculated; Carbon, organic, total; Chlorophyll a, areal concentration; Chukchi Abyssal Plain; Chukchi shelf; Chukchi solpe; DEPTH, sediment/rock; Element analyser CHN, LECO; Elevation of event; Event label; Fluorometric assay of acetone extraction (GF/F filtered); Latitude of event; Lomonosov Ridge, Arctic Ocean; Longitude of event; Mendeleev Ridge, Arctic Ocean; Mendeleev slope; Mixing depth; North Pole; Phaeopigments, areal concentration; Siberia Abyssal Plain; Wrangel Abyssal Plain
    Type: Dataset
    Format: text/tab-separated-values, 134 data points
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  • 5
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 110 (1999), S. 11390-11398 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We examine the distribution of normal-mode coordinates (defined via the eigenvectors of a chain of harmonic oscillators) for a system of purely repulsive hard rods in one dimension. We obtain an exact solution for the singlet density distribution, and separately for the covariances of the normal-mode coordinates. The hard-rod behavior is examined in terms of its deviation from the corresponding distributions for the system of harmonic oscillators. All off-diagonal covariances are zero in the hard-rod system, and the (on-diagonal) variances vary with the normal-mode wave number exactly as in the harmonic system. The detailed singlet normal-mode density distributions are very smooth but nonanalytic, and they differ from the (Gaussian) distributions of the corresponding harmonic system. However, all of the normal-mode coordinate distributions differ in roughly the same way when properly scaled by the distribution variance, and the differences vanish as 1/N in the thermodynamic limit of an infinite number of particles N. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Biochemistry 20 (1981), S. 6446-6457 
    ISSN: 1520-4995
    Source: ACS Legacy Archives
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 60 (1986), S. 1131-1134 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have examined the properties of (InGa)As/GaAs strained-layer superlattices (SLSs) that have been disordered by implantation of 5×1015/cm2, 250 keV 64Zn+ followed by controlled atmosphere annealing at 680 °C for 30 min. Ion channeling techniques indicate that the Zn-disordered regions of the SLS contain extensive crystalline damage after annealing. Simulations of the disordering process using an analytic ion range code predict that the electrical junction resulting from the implantation process is located outside the disordered region of the SLS in both the vertical and the lateral directions. Junction electroluminescence intensity for given drive current densities from the Zn-disordered SLS devices is comparable to that from reference Be-implantation-doped (SLS retained) devices and greatly exceeds that from heavily dislocated grown-junction mesa diodes in the homogeneous alloy of the average SLS composition; this result is consistent with the results of the simulations. This study demonstrates that implantation disordering can be as useful for strained-layer systems as for less severely mismatched heterojunction systems.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Radiography is a heavily used tool for diagnosing laser-based hydrodynamic experiments. A successful experiment relies on the gathering of data over a time window where the relevant physics occurs and on an accurate analysis of those data. Comparison of this experimental data to theory is often best done by generating simulated images from hydrodynamic calculations, including all necessary and important experimental details. Care must be taken to treat both the experimental and theoretical images identically in the analysis. Frequently, image filtering and enhancement routines are used to obtain interface location and perturbation information from the radiographic image. Previous techniques were found to be too sensitive to global image details. New procedures have been developed which utilize local operators that provide better edge or interface identification without bias. These procedures are benchmarked and validated using static radiographic targets of known configuration that mock up experimental situations of interest. The experiment and the image analysis development are described, including discussion of key contributions to the uncertainty of the results.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: This project developed an automated controller based on an artificial neural network and evaluated its applicability in a real-time environment. This capability was developed within the context of a small angle negative ion source on the Discharge Test Stand at Los Alamos. The controller processes information obtained from the beam current wave form, developing a figure of merit (fom) to determine the ion source operating conditions. The fom is composed of the magnitude of the beam current, the stability of operation, and the quietness of the beam. Using no knowledge of operating conditions, the controller begins by making of rough scan of the four-dimensional operating surface. This surface uses as independent variables the anode and cathode temperatures, the hydrogen flow rate, and the arc voltage. The dependent variable is the fom described above. Once the rough approximation of the surface has been determined, the network formulates a model from which it determines the best operating point. The controller takes the ion source to that operating point for a reality check. As real data is fed in, the model of the operating surface is updated until the neural network's model agrees with reality. The controller then uses a gradient ascent method to optimize the operation of the ion source. Initial tests of the controller indicate that it is remarkably capable. It has optimized the operation of the ion source on six different occasions bringing the beam to excellent quality and stability.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 85 (1999), S. 6682-6685 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have investigated the magnetization reversal and magnetoresistance (MR) behavior of a lateral spin-injection device. The device consists of a two-dimensional electron gas (2DEG) system in an InAs quantum well and two ferromagnetic (Ni80Fe20) contacts: an injector (source) and a detector (drain). Spin-polarized electrons are injected from the first contact and propagating through InAs are collected by the second contact. By engineering the shape of the permalloy film distinct switching fields (Hc) from the injector and the collector have been observed by scanning Kerr microscopy and MR measurements. Magneto-optic Kerr effect (MOKE) hysteresis loops demonstrate that there is a range of magnetic field (20–60 Oe), at room temperature, over which magnetization in one contact is aligned antiparallel to that in the other. The MOKE results are consistent with the variation of the magnetoresistance in the spin-injection device. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
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