Wheat is regarded as one of the most important West Asian domesticates that were introduced into Late Neolithic/Early Bronze Age China. Despite a growing body of archaeological data, the timing and routes of its dispersal remain controversial. New radiocarbon (C) dating evidence from six archaeological sites in the Shandong and Liaoning Peninsulas and Bayesian modelling of available C data from China suggest that wheat appeared in the lower Yellow River around 2600 Before Common Era (BCE), followed by Gansu and Xinjiang around 1900 BCE and finally occurred in the middle Yellow River and Tibet regions by 1600 BCE. These results neither support long-standing hypotheses of a progressive spread of wheat agriculture from Xinjiang or Gansu to eastern China nor suggest a nearly synchronous appearance in this vast zone, but corroborate transmission to lower Yellow River elites as an exotic good through cultural interactions with the Eurasian steppe along north-south routes.

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This paper investigates the stabilization of a class of chaotic systems with both model uncertainty and external disturbance. By combining the dynamic feedback control method, and the uncertainty and disturbance estimator (UDE)-based control method, a new UDE-based control method is developed. By using this method, the system stabilization can be achieved by three steps. Illustrative examples using numerical simulations verify the soundness and effectiveness of the proposed method.

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This paper investigates the adaptive finite-time robust control problem of a class of nonlinear time-delay Hamiltonian systems via the Lyapunov-Krasovskii (L-K) method, and proposes some delay-dependent results on the issue. Different from existing works, this paper first presents a time-varying finite-time stability (FTS) criterion via an L-K functional approach, and obtains two FTS conditions by constructing specific L-K functionals. Then, the adaptive finite-time robust control problem is investigated for nonlinear time-delay port-controlled Hamiltonian (PCH) systems, and a control design procedure is presented. Finally, the effectiveness of the results is demonstrated by an illustrative example.

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(S)-2,15-Cl2-DHTP–boron complex catalyst for the asymmetric Diels–Alder cycloaddition of 2′-hydroxychalcones and dienes was developed and tested. The resulting cyclohexenes with three chiral centers were obtained in high yields (up to 98%) with excellent stereoselectivities (up to >20:1 endo/exo, >99% ee). This catalytic system features high efficiency, broad substrate scopes, and mild reaction conditions. In addition, a DFT study was performed to explain the stereochemical course of the asymmetric induction.