437 research outputs found
Surveys as a Social Experience: The Lingering Effects of Survey Design Choices on Respondents' Survey Experience and Subsequent Optimizing Behavior
We propose that the design of earlier survey sections affects respondents’ response strategy to later unrelated questions. We hypothesize that the structure of the survey is socially construed, and when earlier survey design features are respectful of the rules of social conversation, individuals are more likely to optimize their responses later on and express more satisfaction in end-of-survey evaluations. We find evidence supporting these expectations from two experiments, but more research is needed to sort out the causal mechanism responsible for these effects
Risk of root intrusion by tree and shrub species into sewer pipes in Swedish urban areas
Blockages in sewer pipes caused by roots are very common and several tree and shrub species are reported to be particularly likely to cause root intrusion. This study examined the relative ability of roots of different species to intrude into urban sewer pipes.
Data on root-intruded pipes and the woody plants surrounding these pipes were collected from two Swedish cities, Malmö and Skövde. Plant material, location data and closed-circuit television (CCTV) inspections on root-intruded pipes with a total length of 33.7 km, containing 2180 different points of root intrusion, were examined. An inventory of 4107 woody plants was compiled.
The results showed that broad-leaved trees dominated as a cause of root intrusion, but that conifers and a number of shrubs, e.g. the genera Ligustrum, Spiraea and Syringa, were also likely to have caused root intrusion. Malus floribunda Van Houtte was found to have the highest mean share of root intrusions per estimated number of pipe joints when all joints and all root intrusions within a 10 m radius from trees were calculated (0.694, maximum number of intrusions per joint 1.0), while Populus canadensis ‘Robusta’ Moench had the second highest, with 0.456 intrusions per estimated joint. However, other Malus and Populus species and cultivars had a much lower mean share of root intrusions.
Most species seemed capable of causing root intrusion, and not only species of the genera Populus and Salix that were previously seen as the species most likely to cause damage to stormwater and sewer systems. There were differences in the frequency of joint intrusion by roots of different species, but the reasons for these differences were not identified and further research in the area is needed
A MUSE map of the central Orion Nebula (M 42)
We present a new integral-field spectroscopic dataset of the central part of
the Orion Nebula (M 42), observed with the MUSE instrument at the ESO VLT. We
reduced the data with the public MUSE pipeline. The output products are two
FITS cubes with a spatial size of ~5.9'x4.9' (corresponding to ~0.76 pc x 0.63
pc) and a contiguous wavelength coverage of 4595...9366 Angstrom, spatially
sampled at 0.2". We provide two versions with a sampling of 1.25 Angstrom and
0.85 Angstrom in dispersion direction. Together with variance cubes these files
have a size of 75 and 110 GiB on disk. They represent one of the largest
integral field mosaics to date in terms of information content. We make them
available for use in the community. To validate this dataset, we compare world
coordinates, reconstructed magnitudes, velocities, and absolute and relative
emission line fluxes to the literature and find excellent agreement. We derive
a two-dimensional map of extinction and present de-reddened flux maps of
several individual emission lines and of diagnostic line ratios. We estimate
physical properties of the Orion Nebula, using the emission line ratios [N II]
and [S III] (for the electron temperature ) and [S II] and [Cl III] (for
the electron density ), and show two-dimensional images of the velocity
measured from several bright emission lines.Comment: Resubmitted to A&A after incorporating referee comments; access to
full dataset via http://muse-vlt.eu/science/data-release
Decontamination efficiency and waste generation for the decontamination of radioactively contaminated urban and rural environments
A radioactive fallout following a nuclear accident can result in contamination of large areas of land. In order to protect human health against ionizing radiation, large-scale decontamination that includes multiple sets of clean-up measures may be necessary. Sweden lacks national experience of this type of large-scale decontamination. There are thus great uncertainties in the effect of such a decontamination which is dependent on the efficiency and waste generation of the individual remediation measures. In this report, the results from a literature review of the Japanese experience of decontamination after the nuclear accident in Fukushima-Daiichi, 2011, are highlighted. We show that the Japanese decontamination efficiency was on average about 12 percentage points lower than the decontamination efficiencies listed in reference literature on radioactive material decontamination. Removed contaminated soil is by far the largest contribution to radioactive waste production during decontamination. There is a positive correlation between reduced radiation dose rate and amount of soil removed during decontamination. Over time, however, ecological processes contribute by far the most to reduced radiation dose rates. The results can be an important contribution to current decontamination strategies and valuable for responsible agencies and authorities in the case of nuclear fallout incident
Model-based phase velocity and attenuation estimation in wideband ultrasonic measurement systems
δ13C – A useful tool of source characterization of the carbonaceous aerosol at rural measurement sites?
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