4,313 research outputs found
Carabus (Coleoptera: Carabidae) assemblages of native forests and non-native plantations in Northern China
The effects of non-native plantation established after clear-cutting were studied in Dongling Mountain region, Northern China. Pitfall catches of Carabus beetles from a non-native larch plantation were compared with those from two native forests, an oak forest and a mixed broad-leaved forest. More individuals were captured from the mixed broad-leaved forest and the larch plantation than from the oak forest. For the threemost abundant species in this area, C. crassesculptus peaked in abundance in the mixed broad-leaved forest; C. manifestus peaked in the larch plantation, and C. sculptipennis in the oak forest. Measured by PcoAusing Bray-Curtis index of dissimilarity, species composition of the larch plantation was different from the two native forests, but overlapped remarkably with them. All the three abundant species showed a similar positive relationship between local distribution and abundance. Captures of abundant species were clumped within the forest, but the extent of aggregation among forests was different. Monthly catches of total Carabus, and C. crassesculptus alone, peaked in June–August in all the three forests, but C. manifestus peaked in June and again in August. Our results suggest that the planting of non-native larch does not have a detrimental effect on Carabus assemblages in general, but it changes the spatial distribution and abundance compared to the native forests
Habitat associations and seasonal activity of carabid beetles (Coleoptera: Carabidae) in Dongling Mountain, North China
Habitat distribution and seasonal occurrence of carabid beetles were determined using pitfall traps in 1999 and 2000 in the temperate forest zone of the Dongling Mountain, North China. Eight sites differing in vegetation and moisture were selected so as to represent four habitat types. Carabid assemblages of the six forested habitats (lowland, upland and coppice) weremore similar to each other than to the two shrub assemblages. Lowland forest had the highest species richness, and coppice forest had the highest diversity (H’) and equitability (J). Of the 41 species caught, the 18 most abundant species were divided into four distribution types: habitat generalists, forest generalists, forest specialists, and shrub (or coppice) specialists. Mean catches of all beetles showed clear peaks from May to August in nearly all habitats. The catches of the six most abundant species were more or less positively correlated during the two study years, suggesting their similar habitat preferences
Magnetic Borophenes from an Evolutionary Search
A computational methodology based on ab initio evolutionary algorithms and spin-polarized density functional theory was developed to predict two-dimensional magnetic materials. Its application to a model system borophene reveals an unexpected rich magnetism and polymorphism. A metastable borophene with nonzero thickness is an antiferromagnetic semiconductor from first-principles calculations, and can be further tuned into a half-metal by finite electron doping. In this borophene, the buckling and coupling among three atomic layers are not only responsible for magnetism, but also result in an out-of-plane negative Poisson\u27s ratio under uniaxial tension, making it the first elemental material possessing auxetic and magnetic properties simultaneously
Whole Grain Food Standard System Construction Status and Development Direction
Existing studies have clearly demonstrated that people eating more whole grains have reduced risks of many chronic metabolic diseases compared to those eating less. In the past 20 years, the whole grain industry has developed so rapidly in major developed countries and regions. In recent years, whole grains have also attracted extensive attention in our country. The research and development efforts of the whole grain standards in China have been strengthened. This paper introduced the progress of the global definition consensus of whole grain and whole grain food, summarized the international development status of whole grain raw materials and whole grain food related standards in many countries and institutions, such as the Working Group of ISO Whole Grain, the United States, Canada, the Netherlands, Codex Alimentarius Commission, and so on. This paper also reviewed the present situation of definition of the whole grain and whole grain food related standards in China. More than 20 relevant raw materials, food related standards and production technical regulations and the publishment situation of other whole grain standards in China, including national standards and industry standards and local standards and group standards, were summarized, and some whole grain related standards under formulation were also introduced. Finally, the paper puts forward the development direction and suggestions for the construction of whole grain standard system in China, including fully combining with the actual production situation of China’s whole grain food industry, integrating with international standards, and combining standard testing and certification. On the whole, the gradual improvement of the standard system of the whole grain food industry will help guide and regulate the high-quality and healthy development of the whole grain industry in China, and promote the creation of a diversified and healthy grain food ecology, and provide a technical basis for the development of the whole grain industry
- …