121 research outputs found
New data on the ichthyosaur Platypterygius hercynicus and its implications for the validity of the genus
The description of a nearly complete skull from the late Albian of northwestern France
reveals previously unknown anatomical features of Platypterygius hercynicus (Kuhn 1946),
and of European Cretaceous ichthyosaurs in general. These include a wide frontal forming the
anteromedial border of the supratemporal fenestra, a parietal excluded from the parietal
foramen, and the likely presence of a squamosal, inferred from a very large and deep facet on
the quadratojugal. The absence of a squamosal has been considered as an autapomorphy of
the genus Platypterygius for more than ten years and has been applied to all known species by
default, but the described specimen casts doubt on this putative autapomorphy. Actually, it is
shown that all characters that have been proposed previously as autapomorphic for the genus
Platypterygius are either not found in all the species currently referred to this genus, or are
also present in other Ophthalmosauridae. Consequently, the genus Platypterygius must be
completely revised.Peer reviewe
The Model for the Agricultural Informationalization Benefit Analysis
International audienceBased on the assessment of Agricultural Informationalization level, this paper proposed a model for the Agricultural Informationalization benefit analysis whit the Cobb-Douglas production function, to reveal the connection between agri-information index and the agricultural output, and also we made an empirical analysis of Shandong province. It is proved that the Agricultural Informationalization and the farming population both have a direct and positive impact on the development of rural economy in Shandong Province, especially, the development of the Agricultural Informationalization level has a significant influence on the increase of the rural economy in Shandong province , while the impact brought by agricultural fixed asset investment remains limited. By 1% increase of Agricultural Informationalization level, the rural economy increases by 0.565%, which indicates that Agricultural Informationalization is quite beneficial for the development of Shandong’s agricultural economy
Existence of solutions in continuous-time optimal growth models
Existence of solutions, Optimization, Continuous time, Optimal growth, C61, D91, E13,
Upregulation of two ripening-related genes from a non-climacteric plant (pepper) in a transgenic climacteric plant (tomato)
Activities of promoters from the capsanthin/capsorubin synthase and fibrillin genes, which are molecular markers for ripening in the non-climacteric pepper fruits, have been studied in transgenic tomato plants that produce fruits of the climacteric type (characterized by an increase in respiration and ethylene production). The promoters of both genes were strongly upregulated during tomato fruit ripening in a manner similar to the induction of these genes in pepper fruits. Induction occurred at the mature green stage preceding ripening (a stage when ethylene production and respiration are known to rise in tomato fruits). Ethylene positively influenced the expression of both genes in tomato. Other plant growth regulators, namely abscisic acid, auxin and polyamines, did not alter gene expression. In contrast, water loss strongly induced both promoters. This dehydration-mediated gene induction was inhibited by mitochondrial respiration inhibitors (mainly of the alternative oxidase). A slight positive effect with light, apparently not linked to normal photosynthesis but rather to photooxidative stress, was also observed. Taken together, the data indicate that activation of oxidase systems, leading to changes in the cellular redox balance, mediates the induction of both genes in tomato. Various cellular compartments are likely to be contributors to this process, which leads to the developmental regulation of nuclear genes encoding plastid-located proteins
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