Eternal Nature: Spiritual Haven——The Function of Nature in Rip Van Winkle

Rip Van Winkle is one of the most enduring stories of Washington Irving. It is a fantasy tale about a man who somehow "stepped outside of the mainstream of life" (Chang Yao-xin, 1991: 62). Rip Van Winkle lived in a village near the Hudson River north of New York City. He was a simple, good-natured man; he was, moreover, a kind neighbor and an obedient hen-pecked husband. Yet Rip was lazy and this kept him in constant trouble with his wife. His two favorite past-times were sitting in front of the inn, chatting with his friends, and wandering through the mountains with his dog, Wolf. On one of these trips he met a strange dwarf who invited him to join him and other strange-looking dwarfs in a drinking party and a game called nine-pins, in a remote valley. Rip drank too much of beverage and fell asleep. When he woke up, he found that during just one night, twenty years had vanished and strangers were everywhere. His scolding wife had died, and his son, every bit his counterpart in appearance and personality had grown up to replace him. At last he was reunited with a married daughter and began to live a life the same as before.

Maneuvering target state estimation based on separate model-ing of target trajectory shape and dynamic characteristics

The state estimation of a maneuvering target,of which the trajectory shape is independent on dynamic characteristics,is studied.The conventional motion models in Cartesian coordinates imply that the trajectory of a target is completely determined by its dynamic characteristics.However,this is not true in the applications of road-target,sea-route-target or flight route-target tracking,where target trajectory shape is uncoupled with target velocity properties.In this paper,a new estimation algorithm based on separate modeling of target trajectory shape and dynamic characteristics is proposed.The trajectory of a target over a sliding window is described by a linear function of the arc length.To determine the unknown target trajectory,an augmented system is derived by denoting the unknown coefficients of the function as states in mileage coordinates.At every estimation cycle except the first one,the interaction(mixing)stage of the proposed algorithm starts from the latest estimated base state and a recalculated parameter vector,which is determined by the least squares(LS).Numerical experiments are conducted to assess the performance of the proposed algorithm.Simulation results show that the proposed algorithm can achieve better performance than the conventional coupled model-based algorithms in the presence of target maneuvers.

A meshless model for transient heat conduction analyses of 3D axisymmetric functionally graded solids

A meshless numerical model is developed for analyzing transient heat conductions in three-dimensional （3D） axisymmetric continuously nonhomogeneous functionally graded materials （FGMs）. Axial symmetry of geometry and boundary conditions reduces the original 3D initial-boundary value problem into a two-dimensional （2D） problem. Local weak forms are derived for small polygonal sub-domains which surround nodal points distributed over the cross section. In order to simplify the treatment of the essential boundary conditions, spatial variations of the temperature and heat flux at discrete time instants are interpolated by the natural neighbor interpolation. Moreover, the using of three-node triangular finite element method （FEM） shape functions as test functions reduces the orders of integrands involved in domain integrals. The semi-discrete heat conduction equation is solved numerically with the traditional two-point difference technique in the time domain. Two numerical examples are investigated and excellent results are obtained, demonstrating the potential application of the proposed approach.

Variation of the Energy Field of Longmenshan Fault Zone before the Wenchuan M_S 8. 0 Earthquake

During the process of preparation and occurrence of a large earthquake, the stress-strain state along the fault zone has close relation with the weak seismicity around the fault zone. The seismic energy release near the fault zone before an earthquake can better reflect the dynamic process of earthquake preparation. Thus, in this paper, the method of natural orthogonal function expansion has been adopted to discuss the time variation about the energy field of the seismic activity along the Longmenshan fault zone before the Wenchuan MsS. 0 earthquake, 2008. The results show that evident short-term rise changes appeared in the time factors of the typical field corresponding to several key eigenvalues of the energy field along the Longmenshan fault zone before the Wenchuan earthquake, probably being the short-term anomaly message for this earthquake. Through contrastive analysis of earthquake examples such as the 1976 Tangshan earthquake, the authors think that the study of time variation of energy field of seismicity along active fault zone will be helpful for conducting intentional and intensive earthquake monitoring and forecast in active fault regions with high seismic risk based on medium- and long-term earthquake trend judgment.

Gut Microbiota Brings a Novel Way to Illuminate Mechanisms of Natural Products in vivo

Poor bioavailability and undefined major/direct targets are two major obstacles for herbal medicines and natural products（NPs） to elucidate their precise mechanisms in vivo. Gut microbiota is an important bridge between eukayotic body and environment, which can interact with a majority of medicines with poor bioavailability and mediate their in vivo pharmacological activities. There are two main modes through which gut microbiota may mediate the pharmacological effects of NPs. First, gut microbiota catabolizes the NPs in herbal medicines into secondary metabolites with higher bioavialability and/or higher activity, facilitating the NPs enter circulation and exert beneficial impact at the pathological spot. Second, herbal medicines and NPs can favorably shift the compositional structure of gut microbiota, thereby performing remote functions to diseased organs/tissues via the systemic impaction of gut microbiota. In this review, the potential pathways were summarized through which gut microbes facilitate the pharmacological functions of herbal medicines and NPs and highlight the significance of gut microbiota in clarifying the in vivo mechanisms of herbal medicines and NPs.

Genes functional identification and synthetic biology of natural products

Synthetic biology is one of the rapid developing scientific fields in recent years. Through synthetic biology,we have a better understanding of the natural synthesis process of natural products, which provides a favorable method to research the diversity of natural products, and also provides new tools for us to create new approach for producing natural products, we can synthesize compounds with different structures by artificial combination of different synthesis modules.