1,026 research outputs found
Visualising Time
This study investigates the visualisation of temporal relationships between objects. A popular method employed for such information visualisations is the time line consisting of a single horizontal axis along which temporal events or objects are depicted at specific points or intervals. The orientation of the temporal progression along the axis line will generally coincide with the orientation of the literary writing progression of the culture and language. For example a time line visualised in a Western culture with English as its literary base will exhibit a temporal progression orientation of early/left, later/right whereas Arabian culture with an Arabic literary base will exhibit the reverse temporal progression orientation. In both cultures and languages temporal metaphor use spatial concepts to describe temporal relationships with no discourse to transversal orientation. This is reflected by never hearing the phrase “the months to the right” but rather “the months ahead”. In science, Einstein showed via his special and general theories of relativity that time and space are interlinked. The scientific rationalisation of time and space along with the use of spatial concepts as temporal metaphor implies that the underlying perception of time is spatial. Information visualisations are the externalisations of our perceptions. Therefore temporal information visualisations should employ spatial visualisation techniques.
This study evaluated spatial visualisation techniques for temporal information visualisations via a web survey. The spatial temporal information visualisations used in the survey employed no temporal cues such as time or date stamps but conferred all temporal progression via spatial cues. The findings from the analysis of the participant responses to the survey showed that spatial cues do impart temporal cues for temporal relationships
The Ends of the Earth: Defining an Australian Sense of an Ending
Both Patrick White and D. H. Lawrence are writers obsessed with the of an ending. Critics have already begup to explore the primary function of apocalypse in much of their respective work; thematically and structurally, it is not hard to see that both authors were haunted (or hounded) by Christian eschatology, and that the apocalyptic types are major sources for interpreting their works
A research methodology study to map the process of initiating and operating a randomised controlled trial of podoconiosis treatment in Northern Ethiopia
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Field Results from Three Campaigns to Validate the Performance of the Miniaturized Laser Heterodyne Radiometer (MiniLHR) for Measuring Carbon Dioxide and Methane in the Atmospheric Column
In a collaboration between NASA GSFC and GWU, a low-cost, surface instrument is being developed that can continuously monitor key carbon cycle gases in the atmospheric column: carbon dioxide (CO2) and methane (CH4). The instrument is based on a miniaturized, laser heterodyne radiometer (LHR) using near infrared (NIR) telecom lasers. Despite relatively weak absorption line strengths in this spectral region, spectrallyresolved atmospheric column absorptions for these two molecules fall in the range of 60-80% and thus sensitive and precise measurements of column concentrations are possible. In the last year, the instrument was deployed for field measurements at Park Falls, Wisconsin; Castle Airport near Atwater, California; and at the NOAA Mauna Loa Observatory in Hawaii. For each subsequent campaign, improvement in the figures of merit for the instrument has been observed. In the latest work the absorbance noise is approaching 0.002 optical density (OD) noise on a 1.8 OD signal. An overview of the measurement campaigns and the data retrieval algorithm for the calculation of column concentrations will be presented. For light transmission through the atmosphere, it is necessary to account for variation of pressure, temperature, composition, and refractive index through the atmosphere that are all functions of latitude, longitude, time of day, altitude, etc. For temperature, pressure, and humidity profiles with altitude we use the Modern-Era Retrospective Analysis for Research and Applications (MERRA) data. Spectral simulation is accomplished by integrating short-path segments along the trajectory using the SpecSyn spectral simulation suite developed at GW. Column concentrations are extracted by minimizing residuals between observed and modeled spectrum using the Nelder-Mead simplex algorithm. We will also present an assessment of uncertainty in the reported concentrations from assumptions made in the meteorological data, LHR instrument and tracker noise, and radio frequency bandwidth and describe additional future goals in instrument development and deployment targe
The crime drop and the security hypothesis
Major crime drops were experienced in the United States and most other industrialised countries for a decade from the early to mid-1990s. Yet there is little agreement over explanation or lessons for policy. Here it is proposed that change in the quantity and quality of security was a key driver of the crime drop. From evidence relating to vehicle theft in two countries it is concluded that electronic immobilisers and central locking were particularly effective. It is suggested that reduced car theft may have induced drops in other crime including violence. From this platform a broader security hypothesis, linked to routine activity and opportunity theory, is outlined
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The impact of local sources and long-range transport on aerosol properties over the northeast U.S. region during INTEX-NA
We use data collected aboard the NASA DC-8 aircraft during the summer 2004, Intercontinental Transport and Chemical Evolution Experiment over North America (INTEX-NA) field campaign to examine the origin, composition, physical and optical properties of aerosols within air masses sampled over and downwind of the northeastern U.S. We note that aerosol concentrations within the region exhibited steep vertical gradients and significant variability in both time and space. An examination of air mass chemical signatures and backward trajectories indicates that transport from four, significantly different source regions contributed to the variability: the subtropical Atlantic Ocean (AO); the U.S. west coast and eastern Pacific (WCP); the U.S. east coast and Midwestern states (EC); and northwest Canada and Alaska (CA). AO air masses were typically confined to below 2 km altitude, exhibited low pollutant contents, contained enhanced levels of sea salt, and were typically observed when the Bermuda High strengthened. The most common air mass present in the upper troposphere, WCP air often contained weak dust and aged pollution enhances from convective input occurring over the central part of the continent. CA air exhibited enhancements in anthropogenic pollution tracers below 2 km and contained some black-carbon rich haze layers between 3 and 5 km that could be traced to forest fires burning in western Canada and Alaska. EC air was prevalent at lower elevations throughout the study area and exhibited enhanced scattering along with elevated levels of sulfate aerosols and combustion tracers. There is an overall balance between the observed cations and anions for all cases, except EC air mass below 4 km
Are the Faraday Rotating Magnetic Fields Local to Intracluster Radio Galaxies?
We investigate the origin of the high Faraday rotation measures (RMs) found
for polarized radio galaxies in clusters. The two most likely origins are,
magnetic fields local to the source, or magnetic fields located in the
foreground intra-cluster medium (ICM). The latter is identified as the null
hypothesis. Rudnick & Blundell (2003) have recently suggested that the presence
of magnetic fields local to the source may be revealed in correlations of the
position angles (PAs) of the source intrinsic linear polarization and the RMs.
We investigate the claim of Rudnick & Blundell to have found a relationship
between the intrinsic PA0 of the radio source PKS 1246-410 and its RM, by
testing the clustering strength of the PA0-RM scatter plot. We show that the
claimed relationship is an artifact of an improperly performed null-experiment.
We describe a gradient alignment statistic aimed at finding correlations
between PA0 and RM maps. This statistic does not require any null-experiment
since it gives a unique (zero) result in the case of uncorrelated maps. We
apply it to a number of extended radio sources in galaxy clusters (PKS
1246-410, Cygnus A, Hydra A, and 3C465). In no case is a significant
large-scale alignment of PA0 and RM maps detected. We find significant
small-scale co-alignment in all cases, but we are able to fully identify this
with map making artifacts through a suitable statistical test. We conclude that
there is presently no existing evidence for Faraday rotation local to radio
lobes. Given the existing independent pieces of evidence, we favor the null
hypothesis that the observed Faraday screens are produced by intracluster
magnetic fields.Comment: accepted by ApJ, 8 pages, 1 figure, minor style improvement
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