681 research outputs found
Genetic Variation and Geographical Differentiation of \u3cem\u3eElymus nutans\u3c/em\u3e (Poaceae: Triticeae) from West China
Elymus nutans Griseb. is not only an important alpine forage grass, but also as a crucial gene pool for improving cereal crops. Understanding and maintaining the genetic diversity of the species are essential for both conservation strategy and breeding programs. However, little is known about its genetic and geographical differentiation patterns. E. nutans is a perennial, caespitose and allohexaploid (2n=6x=42) species that contains the St, H and Y genomes. It is native to temperate and tropical Asia, ranging from western and central Asia in the west to China and Mongolia in the east, from Russia in the north to India and the Himalayas areas in the south (Clayton et al. 2006). It is distributed in the north, northwest and southwest China, particularly in the Qinghai-Tibet Plateau. E. nutans is a valuable forage grass in the alpine regions that is resistant to cold, drought and pests, which can be used to improve cereal crops. In addition, it can play an important role in the restoration of disturbed grasslands and the establishment of artificial grasslands, especially at altitudes from 3,000 to 4,500 m (Chen and Jia 2000). During recent decades, its distribution has contracted because of over-exploitation, habitat destruction and fragmentation. Therefore, it is urgent to understand and monitor the genetic and geographical differentiation of wild germplams of E. nutans
Artefacts in geometric phase analysis of compound materials
The geometric phase analysis (GPA) algorithm is known as a robust and
straightforward technique that can be used to measure lattice strains in high
resolution transmission electron microscope (TEM) images. It is also attractive
for analysis of aberration-corrected scanning TEM (ac-STEM) images that resolve
every atom column, since it uses Fourier transforms and does not require
real-space peak detection and assignment to appropriate sublattices. Here it is
demonstrated that in ac-STEM images of compound materials (i.e. with more than
one atom per unit cell) an additional phase is present in the Fourier
transform. If the structure changes from one area to another in the image (e.g.
across an interface), the change in this additional phase will appear as a
strain in conventional GPA, even if there is no lattice strain. Strategies to
avoid this pitfall are outlined.Comment: 9 pages, 7 figures, Preprint before review, submitted to
Ultramicroscopy 7 April 201
1-(3,5-Dimethoxybenzyl)-1H-pyrrole
The title compound, C13H15NO2, was synthesized from 3,5-dimethoxybenzaldehyde. The dihedral angle between the pyrrole and benzene rings is 89.91 (5)°. In the crystal, weak C—H⋯O and C—H⋯π interactions link the molecules into a three-dimensional network
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