Search results for "Point source"
showing 5 items of 45 documents
A nonstationary cylinder-based model describing group dispersal in a fragmented habitat
2014
International audience; A doubly nonstationary cylinder-based model is built to describe the dispersal of a population from a point source. In this model, each cylinder represents a fraction of the population, i.e., a group. Two contexts are considered: The dispersal can occur in a uniform habitat or in a fragmented habitat described by a conditional Boolean model. After the construction of the models, we investigate their properties: the first and second order moments, the probability that the population vanishes, and the distribution of the spatial extent of the population.
Extending the search for neutrino point sources with iceCube above the horizon
2009
Point source searches with the IceCube neutrino telescope have been restricted to one hemisphere, due to the exclusive selection of upward going events as a way of rejecting the atmospheric muon background. We show that the region above the horizon can be included by suppressing the background through energy-sensitive cuts. This approach improves the sensitivity above PeV energies, previously not accessible for declinations of more than a few degrees below the horizon due to the absorption of neutrinos in Earth. We present results based on data collected with 22 strings of IceCube, extending its field of view and energy reach for point source searches. No significant excess above the atmosp…
Neutrinos below 100 TeV from the southern sky employing refined veto techniques to IceCube data
2020
Many Galactic sources of gamma rays, such as supernova remnants, are expected to produce neutrinos with a typical energy cutoff well below 100 TeV. For the IceCube Neutrino Observatory located at the South Pole, the southern sky, containing the inner part of the Galactic plane and the Galactic Center, is a particularly challenging region at these energies, because of the large background of atmospheric muons. In this paper, we present recent advancements in data selection strategies for track-like muon neutrino events with energies below 100 TeV from the southern sky. The strategies utilize the outer detector regions as veto and features of the signal pattern to reduce the background of atm…
Wpływ punktowych źródeł zanieczyszczeń na jakość wód dolnego biegu Nysy Kłodzkiej
2000
Toxicity of waste dump leachates and sugar factory effluents and their impact on groundwater and surface water quality in the Opole Province in Poland
2000
A battery of Toxkit microbiotests with 4 aquatic species from different trophic levels has been used to evaluate the toxicity of 2 types of point source pollution in the Voivoidship of Opole in Poland: percolating waters from drainage systems of 4 municipal waste dumps and the effluents of a sugar factory. In addition, the toxicity of groundwaters from 2 wells near 2 waste dumps was also assessed. All the drainage waters of the waste dumps and the groundwaters near one dump (an unprotected landfill) showed toxic effects on all the test species, for samples taken in spring as well as in autumn. The well water of the (more recent) waste dump of the City of Opole in turn did not show any toxic…