The lower Paleogene shallow-water limestones in the Tethyan Himalaya of Tibet and their implications for larger foraminiferal evolution, India-Asia collision and PETM-CIE

Fossiliferous limestones in shallow marine environments are important archives for the studies of paleontology, biostratigraphy, paleoenvironment and paleoclimatology as well as geodynamic evolution of their sedimentary basins. In the eastern Tethyan Himalaya, two areas, Tingri and Gamba, expose the best outcrops of the lower Paleogene larger foraminiferal limestones in Tibet. Based on studies of the limestones, ~70 species and ~20 genera of the Paleocene-Early Eocene larger foraminifera have been identified. Following the Oppel Zone s principle, ten Shallow Benthic Zones (SBZs) ranging from SBZ 1 to 10 have been divided at Tingri, and five SBZs comprising SBZ 2, 3, 4, 5, and 7 are recognized at Gamba. A high-resolution Carbon Isotope Excursion (CIE) curve and the SBZ from the same section at Tingri reveal that the Paleocene-Eocene (P-E) boundary in the shallow marine environment is located in the upper part of SBZ 5, where no evident biotic turnover of benthic foraminiferal communities happened. Notably, a transient but distinct Larger Foraminiferal Extinction and Origination (LFEO) event, marking the boundary between SBZ 5 and 6 in Tibet, occurred at the onset of the CIE recovery. Furthermore, based on studies of the larger foraminifera together with other published data in the Tethyan Himalaya, we propose the initial India-Asia continental collision in Tibet took place at the P-E boundary. Interestingly, the high-resolution CIE curve at Tingri shows similar patterns to the most representative one (from ODP 690) from the deep ocean, however, the magnitude is evidently larger in the shallow marine environment than in the deep sea. It reveals that the CIE in the entire ocean had followed certain regular steps to reach the lowest carbon isotope values during the PETM, and the magnitude of the negative CIE may increase from the deep seas to shallow marine environments. However, the mechanisms causing these phenomena are still enigmatic

Correlation between Aphids, Aphidiinae and Hyperparasitoids in Different Habitats

Aphids are one of the major pests of economical crops in China. Field surveys showed that Macrosiphum avence, Rhopalosiphum padi, Schizaphis graminum, Myzus persicae, Aphis glycines and Lipaphis erysimi are the main aphid species found in agricultural fields. Besides lady beetles and spiders, aphidiine braconids also play an important role in controlling aphids, including Ephedrus plagiator, E. nacheri, Aphidius euenae, Diaeretiella rapae, A. ervi, and A. picipes. However, Aphidiinae are also attacked by many hyperparasitoids, which include Aphidencyrtus aphidivorus, Pachyneuron aphidis, Asaphes vulgaris, Lygocerus koebelai and Figites sp.Originating text in Chinese.Citation: Zhang, Guoan, Guan, Yue, Wang, Qinghai. (2000). Correlation between Aphids, Aphidiinae and Hyperparasitoids in Different Habitats. 8th National Biological Control Conference, Symposium on Insect Control by Microbiology, 29-29

Minimally 3-restricted edge connected graphs

AbstractFor a connected graph G=(V,E), an edge set S⊂E is a 3-restricted edge cut if G−S is disconnected and every component of G−S has order at least three. The cardinality of a minimum 3-restricted edge cut of G is the 3-restricted edge connectivity of G, denoted by λ3(G). A graph G is called minimally 3-restricted edge connected if λ3(G−e)<λ3(G) for each edge e∈E. A graph G is λ3-optimal if λ3(G)=ξ3(G), where ξ3(G)=max{ω(U):U⊂V(G),G[U] is connected,|U|=3}, ω(U) is the number of edges between U and V∖U, and G[U] is the subgraph of G induced by vertex set U. We show in this paper that a minimally 3-restricted edge connected graph is always λ3-optimal except the 3-cube

A fourth-order unfitted characteristic finite element method for solving the advection-diffusion equation on time-varying domains

We propose a fourth-order unfitted characteristic finite element method to solve the advection-diffusion equation on time-varying domains. Based on a characteristic-Galerkin formulation, our method combines the cubic MARS method for interface tracking, the fourth-order backward differentiation formula for temporal integration, and an unfitted finite element method for spatial discretization. Our convergence analysis includes errors of discretely representing the moving boundary, tracing boundary markers, and the spatial discretization and the temporal integration of the governing equation. Numerical experiments are performed on a rotating domain and a severely deformed domain to verify our theoretical results and to demonstrate the optimal convergence of the proposed method