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The solar photon flux distribution was measured in the range from 400 to 1100 nm under a twin-span glasshouse and under the same glasshouse with blanked roof, external shading net and internal aluminized shade-screen. Measurements were also carried out under a twin-span polyethylene greenhouse, a multi-span greenhouse with fibreglass and a polyethylene tunnel. For each greenhouse configuration, the measured solar photon flux spectra were used to calculate the solar transmission for the photosynthetically active radiation waveband (PAR), from 400 to 700 nm, the near infrared waveband (NIR), from 700 to 1100 nm, and the whole waveband (TOTAL), from 400 to 1100 nm. Other parameters having a physiological interest were also determined: the broadband PAR to TOTAL photon flux ratio and PAR to NIR photon flux ratio; and the morphogenesis-related parameters, such as the red to far red photon flux ratio, the phytochrome equilibrium, the relative cycling rate, the blue to red photon flux ratio and the blue to far red photon flux ratio. The results provided a better insight on the quantitative and qualitative properties of the light environment under each greenhouse configuration. Some significant differences in the values of blue light quality related parameters were found between greenhouses. Minor changes were observed on the PAR:TOTAL and PAR:NIR photon flux ratios, but indicated that glass and blanking tend to enrich the PAR content of the transmitted light, while the two plastic cover materials have the opposite effect, enriching the NIR content. These results stressed the need for a more precise characterization of modifications in light quality induced by greenhouse materials or shading devices as plant photosynthetic and photomorphogenetic responses may be significantly influenced by these modifications.

Une étude par distribution spectrale dans les sous-espaces définis par leur nombre de quasi-particules a été effectuée dans les isotopes pairs de plomb. La comparaison avec des résultats obtenus dans les isotopes d'étain montre que le recouvrement entre les différents sous-espaces est fortement lié à l'interaction résiduelle utilisée. En particulier des états à grand nombre de quasi-particules sont présents à basse énergie. Le problème des états spurieux inhérent à cette méthode, qui sont responsables d'une surestimation du couplage, est abordé et différentes corrections sont proposées aussi bien sur les dimensions, les centroïdes et les largeurs des sous-espaces.

International audience; (Signal-shape processing in analytical chemistry.) When signal evolution (e.g., spectra) has to be detected or measured, shape processing can be useful. The distribution function method enables all the information in the signal shape to be utilized, by working with normalized integrals. The concept of shape also helps in estimating resolution parameters of overlapped peaks. The principles are outlined and some applications in chromatography and Mössbauer spectrography are summarized.