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Wyszukujesz frazę "Zhao, Q. X." wg kryterium: Autor


Wyświetlanie 1-3 z 3
Tytuł:
Ontogenetic stages of ceratopsian dinosaur Psittacosaurus in bone histology
Autorzy:
Zhao, Q.
Benton, M.J.
Hayashi, S.
Xu, X.
Powiązania:
https://bibliotekanauki.pl/articles/20498.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Opis:
The early ceratopsians Psittacosaurus and Protoceratops have provided important information on dinosaurian development because of abundant specimens of adults, subadults, juveniles, and even hatchlings. Here we present new data and methods for identifying key growth stages from bone histology. Previous studies on Psittacosaurus lujiatunensis from the Early Cretaceous Jehol Biota of China did not present in-depth analysis of growth patterns. Based on a histological study of 43 thin sections from 17 individuals of this species, we recognize four histological ontogenetic stages, i.e., hatchling, juvenile, sub-adult, and adult, but no fully-grown stage. We estimate life history and longevity from diaphyseal growth line counts and other features of histology. We show that P. lujiatunensis grew fast in early stages (hatchling, juvenile, and subadult), according to the density of vascular canals and the different type of bone tissue; the deposition of parallel fibred bone tissue in the outer cortex of the subadult stage indicates that growth rate was slowing down. We introduce a new graphical method to estimate the occurrence and volumes of vascular canals from thin sections more accurately than current two-dimensional approaches.
Źródło:
Acta Palaeontologica Polonica; 2019, 64, 2
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Juvenile-only clusters and behaviour of the Early Cretaceous dinosaur Psittacosaurus
Autorzy:
Zhao, Q.
Benton, M.J.
Xu, X.
Sander, P.M.
Powiązania:
https://bibliotekanauki.pl/articles/21989.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Opis:
It has hitherto been hard to prove that any association of juvenile dinosaurs represents original behaviour rather than sedimentary accumulation, and it has been hard also to determine the ages of such juveniles. A previously described specimen, which consists of an “adult” Psittacosaurus with 34 fully articulated juveniles, turns out to be a composite: the “adult” skull probably has been added, and in any case it is below breeding age. Other juvenile-only clusters have been reported, but the best examples that likely reflect behaviour rather than sedimentary accumulation are specimens from the Early Cretaceous Lujiatun beds in NE China, which were entombed beneath pyroclastic flow deposits. A remarkable juvenile-only cluster of Psittacosaurus shows clear evidence of different ages (five 2-year olds and one 3-year old) based on bone histological analysis. These juveniles may have associated together as a close-knit, mixed-age herd either for protection, to enhance their foraging, or as putative helpers at the parental nest.
Źródło:
Acta Palaeontologica Polonica; 2014, 59, 4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Improvements in timber production of Chinese fir (Cunninghamia lanceolata) per unit forest area in China via tree breeding: Status and challenges
Autorzy:
Zhou, B.
Peng, D.
Zhao, Q.
Yangnan, S.
Yang, S.
Yang, F.
Qu, G.
Tang, W.
Ou, J.
Xiang, W.
Xiang, J.
Deng, X.
Powiązania:
https://bibliotekanauki.pl/articles/2077649.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Instytut Dendrologii PAN
Tematy:
Cunninghamia lanceolata
genetic improvement
timber volumes per unit forest area
wood properties
proposals
recommendations
Opis:
Chinese fir [Cunninghamia lanceolata (Lamb.) Hook] is a fast-growing tree species that is widely planted for timber production in southern China. Many high-quality breeding systems for Chinese fir have been developed using genetic methods. Here, we systematically review progress in increasing Chinese fir timber volumes per unit forest area in China, using genetic methods. We comprehensively assess the objec- tives, strategies, and primary accomplishments of the first to fourth generations of a Chinese fir breeding program. Furthermore, we propose a genetic improvement program and protocol for Chinese fir, and out- line several recommendations with respect to the main challenges associated with using genetic methods to increase timber yields. Finally, we present a series of proposals to increase Chinese fir timber production in China. This review offers insight into genetic improvements that have increased timber volumes of Chi- nese fir over four generations of breeding, and provides direction for future genetic improvements to wood properties.
Źródło:
Dendrobiology; 2020, 83; 43-51
1641-1307
Pojawia się w:
Dendrobiology
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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