Comparison of codes assessing galactic cosmic radiation exposure of aircraft crew

The assessment of the exposure to cosmic radiation onboard aircraft is one of the preoccupations of bodies responsible for radiation protection. Cosmic particle flux is significantly higher onboard aircraft than at ground level and its intensity depends on the solar activity. The dose is usually estimated using codes validated by the experimental data. In this paper, a comparison of various codes is presented, some of them are used routinely, to assess the dose received by the aircraft crew caused by the galactic cosmic radiation. Results are provided for periods close to solar maximum and minimum and for selected flights covering major commercial routes in the world. The overall agreement between the codes, particularly for those routinely used for aircraft crew dosimetry, was better than ±20 % from the median in all but two cases. The agreement within the codes is considered to be fully satisfactory for radiation protection purpose

Morphological and Geochemical Evidence of Eumelanin Preservation in the Feathers of the Early Cretaceous Bird, Gansus yumenensis

Recent studies have shown evidence for the preservation of colour in fossilized soft tissues by imaging melanosomes, melanin pigment containing organelles. This study combines geochemical analyses with morphological observations to investigate the preservation of melanosomes and melanin within feathers of the Early Cretaceous bird, Gansus yumenensis. Scanning electron microscopy reveals structures concordant with those previously identified as eumelanosomes within visually dark areas of the feathers but not in lighter areas or sedimentary matrices. Fourier transform infrared analyses show different spectra for the feathers and their matrices; melanic functional groups appear in the feather including carboxylic acid and ketone groups that are not seen in the matrix. When mapped, the carboxylic acid group absorption faithfully replicates the visually dark areas of the feathers. Electron Paramagnetic Resonance spectroscopy of one specimen demonstrates the presence of organic signals but proved too insensitive to resolve melanin. Pyrolysis gas chromatography mass spectrometry shows a similar distribution of aliphatic material within both feathers that are different from those of their respective matrices. In combination, these techniques strongly suggest that not only do the feathers contain endogenous organic material, but that both geochemical and morphological evidence supports the preservation of original eumelanic pigment residue

Wall fluxes of reactive oxygen species of an rf atmospheric-pressure plasma and their dependence on sheath dynamics

This article was published in the serial, Journal of Physics D: Applied Physics [© IOP Publishing Ltd]. The definitive version is available at: http://dx.doi.org/10.1088/0022-3727/45/30/305205A radio-frequency (rf) atmospheric-pressure discharge in He–O2 mixture is studied using a fluid model for its wall fluxes and their dependence on electron and chemical kinetics in the sheath region. It is shown that ground-state O, O+2 and O− are the dominant wall fluxes of neutral species, cations and anions, respectively. Detailed analysis of particle transport shows that wall fluxes are supplied from a boundary layer of 3–300μm immediately next to an electrode, a fraction of the thickness of the sheath region. The width of the boundary layer mirrors the effective excursion distance during lifetime of plasma species, and is a result of much reduced length scale of particle transport at elevated gas pressures. As a result, plasma species supplying their wall fluxes are produced locally within the boundary layer and the chemical composition of the overall wall flux depends critically on spatio-temporal characteristics of electron temperature and density within the sheath. Wall fluxes of cations and ions are found to consist of a train of nanosecond pulses, whereas wall fluxes of neutral species are largely time-invariant

Agricultural terraces in the Sowie Mountains

Creation or agricultural terraces is one of the main method of anti-erosional protection in the mountain regions. In the Sudetes Mountains the terraces are in many places relict landforms, which developed during previous centuries, when the extent of settlements and agricultural land use was much more widespread. The article presents the agricultural terraces in the Sowie Mts in the context of other, very few studies, which were conductcd in the Sudetes referring to agricultural terraces. Terracing leads to changes of slope longitudinal profiles, dividing them into separate units with erosion dominating in their upper parts and accumulation in lower parts, behind the upper edge of every terrace. The steeper and the longer is the slope, the higher is the terrace. Also the thickness of agricultural sandy-silty layer, which originates from slope wash and ploughing, and accumulates over the terrace edge, increases according to the increase or slope inclination and slope length. The material which is stored within the terraces is enriched with fine-grained particles (sandy-silty), due to the selective character or surface wash. In contrast, the upper parts of slope are left more coarsegrained. The material accumulated within the terraces allows for estimation of the minimum anthropogenic denudation from slopes under present or former ploughing. The values of denudation for the Sudetes range from 0,09 to 2,7 mm year⁻¹ and depend strongly on lithology, slope inclination and length

Towers and viewing points in Kłodzko Land landscape

Increasing belief that former forms of touristic management, with simultaneous interest of self-governments and social organizations, in development of various form of tourism based on searching for new "touristic products" which can be sold with a profit caused a surprisingly high interest in viewing towers so characteristic for the Sudeten. The apogee of their creation was on the brink of the 19th and 20th century. Only a few of them which were erected at that time were preserved until now in good technical shape and serve the initial purpose. Most of them were devastated or completely disappeared from the landscape. Others lost their viewing value because of the growth of trees surrounding them. Many self-governments from the Sudeten region are presently planning (most commonly basing on expected European Union resources) rebuilding or more often building viewing towers in their areas. The problem increases, especially if we take into consideration the fact that each tower is a far-reaching intrusion on the landscape, regularly already protected by law or deserving such protection. Even an open-worked, light tower becomes a landscape dominant mark, due to its location at altitude. To control the situation and direct such tendencies an attempt was made, in co-operation with self-governments, to define the scale of the problem and pointing out possible locations of towers and viewing points in the area of Kłodzko Land with use of the objects which already exist, both managed and those which were not exploited up to now

Effect of Laser Radiation on Free Radicals in Human Cancer G361 Cells

EPR spectroscopy was used to the examination of free radicals evolution in cancer G361 cells during photodynamic therapy. The cancer cells were cultured with photosensitizer ALA and irradiated with 635 nm light by laser. The number of cells was determined microscopically. The decrease in the cell number and the increase in free radicals, obtained for G361 cells cultured with ALA and irradiated with laser, were stronger than relevant changes for the cells which were only irradiated with laser. The studied melanotic cells susceptible for photodynamic therapy differ from the other melanotic SK human cancer cells by fast spin-lattice relaxation processes. Slow spin-lattice relaxation processes exist in the studied earlier non susceptible for photodynamic therapy SK cells