[en] The electromagnetic polarizabilities of the nucleon are fundamental nucleon-structure observables that characterize its response to external electromagnetic fields. The neutron polarizabilities can be accessed from Compton-scattering data on light nuclear targets. Recent measurements of the differential cross section for Compton scattering on the deuteron below the pion-production threshold have decreased the uncertainties in the neutron polarizabilities, yet the proton polarizabilities remain known substantially more accurately. As the sensitivity of the cross section to the polarizabilities increases with incident photon energy, measurements above the pion threshold may offer a way for an improved determination of the neutron polarizabilities. In this work, the first measurement of the cross section for Compton scattering on the deuteron above the pion-production threshold is presented.

[en] In chiral perturbation theory, the leading-order contribution to reactions with pions in the sector of odd intrinsic parity is defined by the Wess-Zumino-Witten structure. This structure is supplemented by a simple vector-meson Lagrangian where the vector mesons are described by antisymmetric tensor fields. With the rho-omega-pion coupling as the only parameter in the sector of odd intrinsic parity, i.e. without additional contact terms, one can achieve a proper description of the single- and double-virtual pion transition form factor and the three-pion production in electron-positron collisions. (authors)

[en] Fine particles are formed in a variety of processes, both natural and anthropogenic. Epidemiological studies have shown an association between exposure to particulate matter and adverse health effects. Airborne particles contain a variety of compounds, including polycyclic aromatic hydrocarbons (PAHs), and several of the PAHs are known or suspected carcinogens. In this study, stationary measurements of PM_2.5 were performed in the residences of 20 study participants along with simultaneous monitoring at an urban background site. The collected particle mass was then analyzed for its content of some particle-bound PAHs using GC-MS. The median level of PM_2.5 indoors was 7.3 μg/m³ and in urban background 5.3 μg/m³. For benzo(a)pyrene (B(a)P) the corresponding results were 10 pg/m³ and 35 pg/m³, respectively. There were significant correlations between indoor and ambient levels for both PM_2.5 (r_s=0.58, p=0.02) and B(a)P (r_s=0.67, p=0.007). No significant correlation was, however, found between the concentration of PM_2.5 and the associated levels of the investigated PAH compounds. This finding implies that exposure to B(a)P or other particle-bound PAH components needs to be separately assessed.

[en] An experiment that aims to measure the π"− photoproduction cross-section σ(E) on the deuteron γ + "2H → π"− + 2p near threshold is discussed. The main concepts of the experimental technique are presented alongside some preliminary signals.

[en] Highlights: • The aim was to investigate the effect of herbicides in an agro-ecosystem setting. • The levels of glyphosate in the field were estimated by measuring a dye tracer. • The deposition of glyphosate decreased rapidly with increasing distance. • Glyphosate had a significantly negative effect on the cumulative number of flowers. • Glyphosate did not affect the flowering time on any of the species significantly. Recent studies have shown that sub-lethal doses of herbicides may affect plant flowering, however, no study has established a direct relationship between the concentrations of deposited herbicide and plant flowering. Here the aim was to investigate the relationship between herbicide spray drift deposited on non-target plants and plant flowering in a realistic agro-ecosystem setting. The concentrations of the herbicide glyphosate deposited on plants were estimated by measuring the concentration of a dye tracer applied together with the herbicide. The estimated maximal and average deposition of glyphosate within the experimental area corresponded to 30 g glyphosate/ha (2.08% of the label rate of 1440 g a.i./ha) and 2.4 g glyphosate/ha (0.15% label rate), respectively, and the concentrations decreased rapidly with increasing distance from the spraying track. However, there were not a unique relation between distance and deposition, which indicate that heterogeneities of turbulence, wind speed and/or direction can strongly influence the deposition from 1 min to another during spraying. The effects of glyphosate on cumulative flower numbers and flowering time were modelled using Gompertz growth models on four non-target species. Glyphosate had a significantly negative effect on the cumulative number of flowers on Trifolium pratense and Lotus corniculatus, whereas there were no significant effects on Trifolium repens, and a positive, but non-significant, effect on number of flowers on Cichorium intybus. Glyphosate did not affect the flowering time of any of the four species significantly. Lack of floral resources is known to be of major importance for pollinator declines. The implications of the presented results for pesticide risk assessment are discussed.

[en] Declining plant diversity and abundance have been widely reported in agro-ecosystems of North America and Europe. Intensive use of herbicides within cropfields and the associated drift in adjacent habitats are partly responsible for this change. The objectives of this work were to quantify the phenological stages of non-target plants in in-situ field situations during herbicide spray and to compare plant susceptibility at different phenological stages. Results demonstrated that a large number of non-target plants had reached reproductive stages during herbicide spray events in woodlots and hedgerows, both in Canada and Denmark where vegetation varies considerably. In addition, delays in flowering and reduced seed production occurred widely on plants sprayed at the seedling stage or at later reproductive periods, with plants sprayed at reproductive stages often exhibiting more sensitivity than those sprayed as seedlings. Ecological risk assessments need to include reproductive endpoints. -- Highlights: • Many non-target plants have reached reproductive stages at herbicide spray time. • Delay and reduction in reproduction occurred on plants sprayed at seedling stage. • Reproduction was often reduced on plants sprayed during reproductive periods. • Reproductive stages often exhibited more sensitivity than the seedling stage. • Ecological risk assessment should include tests with reproductive endpoints. -- Herbicides delayed/reduced reproduction of non-target plants when sprayed at seedling and reproductive stages; flower and seed production are sensitive endpoints

[en] High-statistics measurements of the photon asymmetry Σ for the vector γp → π"0p reaction have been made in the center-of-mass energy range W = 1214-1450 MeV. The data were measured with the MAMI A2 real photon beam and Crystal Ball/TAPS detector systems in Mainz, Germany. The results significantly improve the existing world data and are shown to be in good agreement with previous measurements, and with the MAID, SAID, and Bonn-Gatchina predictions. We have also combined the photon asymmetry results with recent cross-section measurements from Mainz to calculate the profile functions, Σ (= σ_0Σ), and perform a moment analysis. Comparison with calculations from the Bonn-Gatchina model shows that the precision of the data is good enough to further constrain the higher partial waves, and there is an indication of interference between the very small F-waves and the N(1520)3/2"- and N(1535)1/2"- resonances. (orig.)