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[en] Vascular function after irradiation must depend not only on bulk cell survival, but also on the extent of disruption of the vascular network. The authors describe a model for radiation response in the vasculature which takes into account 1) the average length of the blood vessels at risk for radiation damage, and 2) the degree of arborization of the vascular net. Functional response in the vasculature through a course of fractionated radiation is calculated, assuming equal effect per exposure and a linear-quadratic survival curve for the target vascular cells. The model predicts that 1) large irradiated fields are more sensitive overall to radiation than small fields (volume effect) and 2) sensitivity to dose per exposure in a multi-exposure schedule increases with field size (dose fractionation effect). Depending on the values of the relative vascular lengths and arborization coefficients, the shape of the dose-response curve for vascular function can approximate either the linear-quadratic model or the n,D/sub o/ model for radiation response. The analysis shows that the structural organization of the vasculature can cause an increased sensitivity to dose fractionation even if the individual cells are not as fractionation sensitive. This may be related to the observed greater fractionation sensitivity for late vs acute radiation effects

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[en] A recently proposed novel technique for the detection of cosmic rays with arrays of Imaging Atmospheric Cherenkov Telescopes is applied to data from the High Energy Stereoscopic System (H.E.S.S.). The method relies on the ground-based detection of Cherenkov light emitted from the primary particle prior to its first interaction in the atmosphere. The charge of the primary particle (Z) can be estimated from the intensity of this light, since it is proportional to Z². Using H.E.S.S. data, an energy spectrum for cosmic-ray iron nuclei in the energy range 13-200 TeV is derived. The reconstructed spectrum is consistent with previous direct measurements and is one of the most precise so far in this energy range

[en] This paper presents an original integration of polycrystalline SiGe-based quantum dots superlattices (QDSL) into Thermoelectric (TE) planar infrared microsensors (μSIR) fabricated using a CMOS technology. The nanostructuration in QDSL results into a considerably reduced thermal conductivity by a factor up to 10 compared to the one of standard polysilicon layers that are usually used for IR sensor applications. A presentation of several TE layers, QDSL and polysilicon, is given before to describe the fabrication of the thermopile-based sensors. The theoretical values of the sensitivity to irradiance of μSIR can be predicted thanks to an analytical model. These findings are used to interpret the experimental measurements versus the nature of the TE layer exploited in the devices. The use of nanostructured QDSL as the main material in μSIR thermopile has brought a sensitivity improvement of about 28% consistent with theoretical predictions. The impact of QDSL low thermal conductivity is damped by the contribution of the thermal conductivity of all the other sub-layers that build up the device.

[en] Absolute photodetachment cross sections of two anions of astrophysical importance CN^– and C₃N^– were measured to be (1.18 ± (0.03)_stat(0.17)_sys) × 10^–17 cm² and (1.43 ± (0.14)_stat(0.37)_sys) × 10^–17 cm², respectively, at the ultraviolet (UV) wavelength of 266 nm (4.66 eV). These relatively large values of the cross sections imply that photodetachment can play a major role in the destruction mechanisms of these anions particularly in photon-dominated regions. We have therefore carried out model calculations using the newly measured cross sections to investigate the abundance of these molecular anions in the cirumstellar envelope of the carbon-rich star IRC+10216. The model predicts the relative importance of the various mechanisms of formation and destruction of these species in different regions of the envelope. UV photodetachment was found to be the major destruction mechanism for both CN^– and C₃N^– anions in those regions of the envelope, where they occur in peak abundance. It was also found that photodetachment plays a crucial role in the degradation of these anions throughout the circumstellar envelope