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Articles 1 - 9 of 9
Full-Text Articles in Physical Sciences and Mathematics
Viewing A Graph In A Virtual Reality Display Is Three Times As Good As A 2d Diagram, Colin Ware, Glenn Franck
Viewing A Graph In A Virtual Reality Display Is Three Times As Good As A 2d Diagram, Colin Ware, Glenn Franck
Center for Coastal and Ocean Mapping
An experiment is reported which tests whether network information is more effectively displayed in a three dimensional space than in a two dimensional space. The experimental task is to trace a path in a network and the experiment is carried out in 2D, in a 3D stereo view, in a 2D view with head coupled perspective, and in a 3D stereo view with head coupled perspective; this last condition creates a localized virtual reality display. The results show that the motion parallax obtained from the head coupling of perspective is more important than stereopsis in revealing structural information. Overall the …
Representing Nodes And Arcs In 3d Networks, Glenn Franck, Colin Ware
Representing Nodes And Arcs In 3d Networks, Glenn Franck, Colin Ware
Center for Coastal and Ocean Mapping
This paper introduces six graphical principles for 30 network displays. These are justified with examples from GraphVisualizer3D, a system developed by the authors to investigate the problems of 30 visualization of information networks. GraphVisualizer3D enables the exploration of sulface color, surface texture, object shape, arc shape and labeling conventions.
Temporal Alternation Between Light- And Nutrient-Limitation Of Phytoplankton Production In A Coastal Plain Estuary., Jonathan Pennock, Jonathan H. Sharp
Temporal Alternation Between Light- And Nutrient-Limitation Of Phytoplankton Production In A Coastal Plain Estuary., Jonathan Pennock, Jonathan H. Sharp
School of Marine Science and Ocean Engineering
ABSTRACT: The potential for Light- and nutrient-limitation of phytoplankton production was examined in the Delaware Estuary, USA, by combining a hierarchy of expenmental approaches including smallscale bioassay experiments, ecosystem-level analysis of nutrient concentration and stoichiometric ratios, and light-limitation modeling. Light was found to be the predominate regulator of phytoplankton growth throughout the estuary during the winter period as a result of high turbidity and a wellmixed water column. However, during late spring, phosphorus (P) was found to limit growth. This observation was confirmed at each of the experimental levels, and was related to several factors, including elevated input ratios (230:l) …
Soluble Acidic Species In Air And Snow At Summit, Greenland, Jack E. Dibb, R. Talbot, M H. Bergin
Soluble Acidic Species In Air And Snow At Summit, Greenland, Jack E. Dibb, R. Talbot, M H. Bergin
Earth Sciences
Simultaneous measurements of the concentrations of soluble acidic species in the gas, aerosol and snow phases at Summit, Greenland were made during summer 1993. Mean concentrations of gas phase HCOOH, CH3COOH, and HNO3 (49±28, 32±17 and 0.9±0.6 nmol m−3 STP, respectively) exceeded the concentrations of aerosol-associated HCOO−, CH3COO−, and NO3−by 1–3 orders of magnitude. On average, SO2 concentrations (0.9±0.6 nmol m−3 STP) were approximately 1/3 those of aerosol SO4=, but this ratio varied widely due largely to changes in the concentration of …
Estimation Of Stratospheric Input To The Arctic Troposphere: 7be And 10be In Aerosols At Alert, Canada, Jack E. Dibb, David Meeker, R C. Finkel, J Southon, Marc W. Caffee, Leonard A. Barrie
Estimation Of Stratospheric Input To The Arctic Troposphere: 7be And 10be In Aerosols At Alert, Canada, Jack E. Dibb, David Meeker, R C. Finkel, J Southon, Marc W. Caffee, Leonard A. Barrie
Earth Sciences
Concentrations of 7Be and 210Pb in 2 years of weekly high-volume aerosol samples collected at Alert, Northwest Territories, Canada, showed pronounced seasonal variations. We observed a broad winter peak in 210Pb concentration and a spring peak in 7Be. These peaks were similar in magnitude and duration to previously reported results for a number of stations in the Arctic Basin. Beryllium 10 concentrations (determined only during the first year of this study) were well correlated with those of 7Be; the atom ratio 10Be/7Be was nearly constant at 2.2 throughout the year. This relatively high value of 10Be/7Be indicates that the stratosphere …
Application Of A Maximum Likelihood Processor To Acoustic Backscatter For The Estimation Of Seafloor Roughness Parameters, Zoi-Heleni Michalopoulou, Christian De Moustier
Application Of A Maximum Likelihood Processor To Acoustic Backscatter For The Estimation Of Seafloor Roughness Parameters, Zoi-Heleni Michalopoulou, Christian De Moustier
Center for Coastal and Ocean Mapping
Maximum likelihood (ML) estimation is used to extract seafloor roughness parameters from records of acoustic backscatter. The method relies on the Helmholtz–Kirchhoff approximation under the assumption of a power‐law roughness spectrum and on the statistical modeling of bottom reverberation. The result is a globally optimum, highly automated technique that is a useful tool in the context of seafloor classification via remote acoustic sensing. The general geometry of the Sea Beam bathymetric system is incorporated into the design of the ML processor in order to make it applicable to real acoustic data collected by this system. The processor is initially tested …
Sulfate And Msa In The Air And Snow On The Greenland Ice Sheet, J L. Jaffrezo, C Davidson, M Legrand, Jack E. Dibb
Sulfate And Msa In The Air And Snow On The Greenland Ice Sheet, J L. Jaffrezo, C Davidson, M Legrand, Jack E. Dibb
Earth Sciences
Sulfate and methanesulfonic acid (MSA) concentrations in aerosol, surface snow, and snowpit samples have been measured at two sites on the Greenland Ice Sheet. Seasonal variations of the concentrations observed for these chemical species in the atmosphere are reproduced in the surface snow and preserved in the snowpit sequence. The amplitude of the variations over a year are smaller in the snow than in the air, but the ratios of the concentrations are comparable. The seasonal variations for sulfate are different at the altitude of the Ice Sheet compared to those observed at sea level, with low concentrations in winter …
137cs Gamma-Ray Detection At Summit, Greenland, P. P. Dunphy, Jack E. Dibb
137cs Gamma-Ray Detection At Summit, Greenland, P. P. Dunphy, Jack E. Dibb
Earth Sciences
Global fall-out from atmospheric testing of thermonuclear weapons produced horizon markers corresponding to the initiation of testing in 1953 and the maximum fall-out in 1963. The radioactive isotope 137Cs associated with these events has a half-life of 30.2 years. Therefore, with the appropriate radiation detectors, this fall-out can be used as a long-term temporal indicator in glaciers and snowpack. A prototype γ-ray detector system was successfully tested and was used to make in-situ measurements of the 137Cs marker in a borehole at Summit, Greenland. The system consisted of a 7.6 cm by 7.6 cm NaI (Tl) scintillation crystal/photomultiplier detector, commercial …
An Ice-Core-Based Record Of Biomass Burning In The Arctic And Subarctic, 1750-1980, Sallie I. Whitlow, Paul A. Mayewski, Jack E. Dibb, Mark S. Twickler, G Holdsworth
An Ice-Core-Based Record Of Biomass Burning In The Arctic And Subarctic, 1750-1980, Sallie I. Whitlow, Paul A. Mayewski, Jack E. Dibb, Mark S. Twickler, G Holdsworth
Earth Sciences
No abstract provided.