RESUMO
Data on the reaction γpâK^{+}Λ from the CLAS experiments are used to derive the leading multipoles, E_{0+}, M_{1-}, E_{1+}, and M_{1+}, from the production threshold to 2180 MeV in 24 slices of the invariant mass. The four multipoles are determined without any constraints. The multipoles are fitted using a multichannel L+P model that allows us to search for singularities and to extract the positions of poles on the complex energy plane in an almost model-independent method. The multipoles are also used as additional constraints in an energy-dependent analysis of a large body of pion and photoinduced reactions within the Bonn-Gatchina partial wave analysis. The study confirms the existence of poles due to nucleon resonances with spin parity J^{P}=1/2^{-}, 1/2^{+}, and 3/2^{+} in the region at about 1.9 GeV.
RESUMO
Evidence is reported for the existence of a parity doublet of Delta resonances with total angular momentum J=3/2 from photoproduction of the ppi;{0}eta final state. The two parity partners Delta(1920)P33 and Delta(1940)D33 make significant contributions to the reaction. Cascades of resonances into Delta(1232)eta, N(1535)pi, and Na0(980) are clearly observed.
RESUMO
Barley (Hordeum vulgare), corn (Zea mays), bean (Phaseolus vulgaris), and radish (Raphanus sativus) seedlings were continuously irradiated under a lighting device for 5-10 d at an increased ultraviolet (UV)-B fluence rate. In their growth parameters, composition, and leaf surface, these four species responded differently to the increased UV-B exposure. Bean seedlings suffered the most serious effects, radish and barley less, and corn was hardly influenced at all. In all plant species, the fresh weight, the leaf area, the amounts of chlorophylls, carotenoids and the galactolipids of the chloroplasts were reduced. The lipid content of the corn and bean seedlings also diminished. But all the irradiated plants showed a rise in their protein content compared to the control plants. The content of flavonoids increased in barley and radish seedlings by about 50%. The effects on growth parameters and composition were more extensive with increasing UV-B fluence rates, at least as shown in the case of barley seedlings. The fresh weights fell proportionally with the chlorophylls and carotenoids. In contrast, the flavonoid content of barley leaves rose parallel to the increasing UV-B fluence rates and reached 180% of the value in the control plants with the highest UV-B fluence rate. Scorching appeared regularly in the form of bronze leaf discoloration at the highest UV-B fluence rates. Scanning electron micrographs of the leaf surface of UV-B irradiated plants showed deformed epidermal structures.