Development and Synergetic Evolution of the Water–energy–food Nexus System in the Yellow River Basin

The water–energy–food nexus is a complex system which is especially difficult to achieve as a trade-off in resource-deficient areas. As an area where the shortage of water leads to water–energy–food conflict, investigating the evolution state and spatial characteristics of water–energy–food in the Yellow River Basin is essential for the resource management and sustainable development orientation of the region’s water–energy–food nexus system. This study proposed an integrated assessment framework by using synergy theory and the integrated index system method. The improved Lotka–Volterra symbiotic model was used to elucidate the development and synergy evolution status of the water–energy–food nexus system in prefecture-level cities in the Yellow River Basin between 2004 and 2019. The results show that the development level of water and energy subsystems in the Yellow River Basin increased by 0.12 and 0.42 on average respectively, whereas that of the food subsystem only increased by approximately 0.004 on average compared to the initial year. Furthermore, most prefecture-level cities experienced subsystem degradation for one or two subsystems during the system evolution of the water–energy–food nexus. Based on the uniqueness and evolution process of each city, there are eight possibilities for system evolution and three types of feedback state between each pair of subsystems, which may lead to a certain spatial aggregation. Additionally, the interaction and competition states are more common than synergy states in the water–energy–food nexus system of the Yellow River Basin. This study provides an important basis and suggestions for the internal relationship and sustainable orientation of water–energy–food nexus systems in such water-deficient areas.

Brain regulatory program predates central nervous system evolution

Understanding if bilaterian centralized nervous systems (CNS) evolved once or multiple times has been debated for over a century. Recent efforts determined that the nerve chords found in bilaterian CNSs likely evolved independently, but the origin(s) of brains remains debatable. Developing brains are regionalized by stripes of gene expression along the anteroposterior axis. Gene homologs are expressed in the same relative order in disparate species, which has been interpreted as evidence for homology. However, regionalization programs resemble anteroposterior axial patterning programs, which supports an alternative model by which conserved expression in brains arose convergently through the independent co-option of deeply conserved axial patterning programs. To begin resolving these hypotheses, we sought to determine when the neurogenic role for axial programs evolved. Here we show that the nerve net in the cnidarian Nematostella vectensis and bilaterian brain are regionalized by the same molecular programs, which indicates nervous system regionalization predates the emergence of bilaterians and CNSs altogether. This argues that shared regionalization mechanisms are insufficient to support the homology of brains and supports the notion that axial programs were able to be co-opted multiple times during evolution of brains.

Symbiotic Exploration of Silage Machinery Based on Technological System Evolution

In order to make each functional module of silage machinery have a high degree of adaptability and meet the market demand of coordinated operation of each functional module, this paper preliminarily explores the symbiosis concept in the field of silage equipment, and applies the technology system evolution theory to the symbiotic design of silage equipment. In the design stage, the designers divide the functional modules of the silage machinery according to the market and user needs, and then analyze the symbiosis of the interrelated modules and screen out the functional modules with weak adaptability, so as to carry out the technical system evolution and optimize each functional module, and then establish the layout scheme between modules, so that the various functional modules of the silage machinery have strong adaptability, improve product quality, reduce design costs, shorten the design cycle, and realize the user’s demand for the coordinated operation of multi-functional silage machinery.

Sol-gel system evolution control for the synthesis of gas-sensitive nanomaterials based on semiconductor oxides

The article analyzes conditions for the occurrence of spinodal decomposition in sol-gel systems based on semiconductor oxide precursors, resulting in labyrinthine structures. Such materials are promising for use in chemoresistive gas sensors with increased sensory response. It is shown that system evolution towards these structures is possible due to sol cooling, or increased its maturation time.