435 research outputs found
Doppler images of II Pegasi for 2004-2010
Aims. We study the spot activity of II Peg during the years 2004-2010 to
determine long- and short-term changes in the magnetic activity. In a previous
study, we detected a persistent active longitude, as well as major changes in
the spot configuration occurring on a timescale of shorter than a year. The
main objective of this study is to determine whether the same phenomena persist
in the star during these six years of spectroscopic monitoring.
Methods. The observations were collected with the high-resolution SOFIN
spectrograph at the Nordic Optical Telescope. The temperature maps were
calculated using a Doppler imaging code based on Tikhonov regularization.
Results. We present 12 new temperature maps that show spots distributed
mainly over high and intermediate latitudes. In each image, 1-3 main active
regions can be identified. The activity level of the star is clearly lower than
during our previous study for the years 1994-2002. In contrast to the previous
observations, we detect no clear drift of the active regions with respect to
the rotation of the star.
Conclusions. Having shown a systematic longitudinal drift of the
spot-generating mechanism during 1994-2002, the star has clearly switched to a
low-activity state for 2004-2010, during which the spot locations appear more
random over phase space. It could be that the star is near to a minimum of its
activity cycle.Comment: Accepted for publication in Astron. and Astrophys., 8 pages, 5
figure
“I Did It My Way”: Moving Away from the Tyranny of Turn-by-Turn Pedestrian Navigation
No abstract available
How are biodiversity and dispersal of species affected by the management of roadsides? A systematic map protocol
Background: In many parts of the world, roadsides are regularly managed for traffic-safety reasons. Hence, there are similarities between roadsides and certain other managed habitats, such as wooded pastures and mown or grazed grasslands. In contrast to roadsides, the latter habitats have declined rapidly in Europe during the last century, and today only a fraction of their former extent remains. For many species historically associated with these habitats, roadsides may therefore function as new primary habitats or as dispersal corridors in fragmented landscapes. Current recommendations for roadside management to promote conservation values are largely based on studies of plants in semi-natural grasslands, although such areas often differ from roadsides in terms of environmental factors and impacts. Moreover, roadsides provide habitats not only for plants but also for many insects, especially if they are sandy and exposed to the sun. For these reasons, stakeholders in Sweden have emphasised the need for more targeted management recommendations, based on actual studies of roadside biodiversity.
Methods: The proposed systematic map is intended to provide an overview of the available evidence on how biodiversity is affected by various forms of roadside management, and how such management influences the dispersal of species along roads or roadsides. Relevant interventions include e.g. mowing, shrub removal, control of invasive/nuisance species, sowing or planting, burning, grazing by livestock, scraping and ditching. Non-intervention or alternative forms of roadside management will be used as comparators. Relevant outcomes include measures of species or genetic diversity, the abundance of individual species or groups of organisms, species distribution patterns, and movement rates of individuals or propagules. Searches will be made for peer-reviewed and grey literature in English and several other languages. No geographical restrictions will be applied, and all species and species groups will be considered
Statistical geometry in scalar turbulence
A general link between geometry and intermittency in passive scalar
turbulence is established. Intermittency is qualitatively traced back to events
where tracer particles stay for anomalousy long times in degenerate geometries
characterized by strong clustering. The quantitative counterpart is the
existence of special functions of particle configurations which are
statistically invariant under the flow. These are the statistical integrals of
motion controlling the scalar statistics at small scales and responsible for
the breaking of scale invariance associated to intermittency.Comment: 4 pages, 5 figure
Direction distributions of neutrons and reference values of the personal dose equivalent in workplace fields
Within the EC project EVIDOS, double-differential (energy and direction) fluence spectra were determined by means of novel direction spectrometers. By folding the spectra with fluence-to-dose equivalent conversion coefficients, contributions to H*(10) for 14 directions, and values of the personal dose equivalent Hp(10) and the effective dose E for 6 directions of a person's orientation in the field were determined. The results of the measurements and calculations obtained within the EVIDOS project in workplace fields in nuclear installations in Europe, i.e., at Krümmel (boiling water reactor and transport cask), at Mol (Venus research reactor and fuel facility Belgonucléaire) and at Ringhals (pressurised reactor and transport cask) are presente
An Analysis of Tennessee Agri-Tourism Visitors’ Preferences and Expenditures
Agri-tourism is a relatively new concept in the United States and Tennessee, but it is gaining popularity with agri-business owners as a source of additional income. Because agri-tourism is new, much is left to be understood about what motivates visitors to agri-tourism attractions. This thesis analyzes the results of a visitor survey of 6 agritourism attractions in Tennessee, with a focus on understanding the factors that are motivating people to visit agri-tourism attractions. It was found that the reasons for visitors to attend agri-tourism attractions encompass a complex web of both economic and social motives. Visitors who attend agri-tourism attractions also have an economic effect directly and indirectly on the Tennessee economy
Evaluation of individual dosimetry in mixed neutron and photon radiation fields (EVIDOS). Part II: conclusions and recommendations
The paper presents the main conclusions and recommendations derived from the EVIDOS project, which is supported by the European Commission within the 5th Framework Programme. EVIDOS aims at evaluating state of the art neutron dosimetry techniques in representative workplaces of the nuclear industry with complex mixed neutron-photon radiation fields. This analysis complements a series of individual papers which present detailed results and it summarises the main findings from a practical point of view. Conclusions and recommendations are given concerning characterisation of radiation fields, methods to derive radiation protection quantities and dosemeter result
Neutron area survey instrument measurements in the EVIDOS project
Neutron survey instruments have been exposed at all the measurement locations used in the EVIDOS project. These results have an important impact in the interpretation of the results from the project, since operationally the survey instrument will be used for an initial assessment of and routine monitoring of the ambient dose equivalent dose rate. Additionally, since the response of these instruments is in some cases very well characterised, their systematic deviations from the reference quantities provide an important verification of the determination of those quantitie
Summary of personal neutron dosemeter results obtained within the EVIDOS project
Within the EC project EVIDOS (‘Evaluation of Individual Dosimetry in Mixed Neutron and Photon Radiation Fields'), different types of active neutron personal dosemeters (and some passive ones) were tested in workplace fields at nuclear installations in Europe. The results of the measurements which have been performed up to now are summarised and compared to our currently best estimates of the personal dose equivalent Hp(10). Under- and over-readings by more than a factor of two for the same dosemeter in different workplace fields indicate that in most cases the use of field-specific correction factors is require
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