In the early 1990s, China stepped into the stage of rapid urbanization with a flourishing economy and new technological development. Surplus labor from rural areas flooded into cities and became the ...main force of urban development. However some severe threats to human survival emerged from urbanization, such as over-extensive urban development, excessive resource consumption, ecological degradation, food security and safety risks and social crises. It has become an imperative to balance urban and rural development to achieve greater harmony between nature and society. This paper firstly tried to focus on public dietary change, agricultural industry development, institutional guarantee, ecological restoration, as well as cultural tourism in urban and peri-urban agricultural heritage sites. Then, it established a development model, balanced the urbanization and urban-supported agriculture. This paper proposed “Agricultural heritage systems” as an entry point for balancing the development of urban areas and rural areas. Agricultural heritage systems can inherit local traditional culture, keep the green and organic agriculture cultivation systems, exploit the distinct landscape tourism, and the like for diversified development; In addition, agricultural heritage systems can take full advantage of abundant funds, firm the institutional guarantee and advanced technologies from the nearby urban complex for regurgitation-feeding of rural enterprises. With the help of these strategies, we can achieve the harmony of “Ecological Urban” and “Garden Countryside”.
Eighteen microsatellite markers were used to determine the genetic distances between the parental gametophyte clones of 14 Laminaria hybrids, which were then used to establish a linear relationship ...with the heterosis (hybrid vigor) of economic traits including yield, mean blade try weight, mean blade fresh weight, blade length, blade width and mean blade thickness using regression analysis. Significant regression was found between the genetic distance (x) and the heterosis (y) of yield (y = 115.10x - 77.97, r = 0.8151, p = 0.00038), mean blade dry weight (y = 115.23x -77.97, r = 0.8154, p = 0.00038), mean blade fresh weight (y = 100.08x - 57.85, r = 0.7306, p = 0.0030) and blade length (y = 204.11x - 46.77, r = 0.6963, p = 0.00566). The prediction of the heterosis of Laminaria hybrids with the genetic distance between parental gametophyte clones will facilitate the selection of elite Laminaria hybrids by avoiding the time-consuming and labor-intensive trait evaluation of a large number of hybridization combinations.
We propose CoNSAL (Combining Neural networks and Symbolic regression for Analytical Lyapunov function) to construct analytical Lyapunov functions for nonlinear dynamic systems. This framework ...contains a neural Lyapunov function and a symbolic regression component, where symbolic regression is applied to distill the neural network to precise analytical forms. Our approach utilizes symbolic regression not only as a tool for translation but also as a means to uncover counterexamples. This procedure terminates when no counterexamples are found in the analytical formulation. Compared with previous results, CoNSAL directly produces an analytical form of the Lyapunov function with improved interpretability in both the learning process and the final results. We apply CoNSAL to 2-D inverted pendulum, path following, Van Der Pol Oscillator, 3-D trig dynamics, 4-D rotating wheel pendulum, 6-D 3-bus power system, and demonstrate that our algorithm successfully finds their valid Lyapunov functions. Code examples are available at https://github.com/HaohanZou/CoNSAL.
Neural operator approximations of the gain kernels in PDE backstepping has emerged as a viable method for implementing controllers in real time. With such an approach, one approximates the gain ...kernel, which maps the plant coefficient into the solution of a PDE, with a neural operator. It is in adaptive control that the benefit of the neural operator is realized, as the kernel PDE solution needs to be computed online, for every updated estimate of the plant coefficient. We extend the neural operator methodology from adaptive control of a hyperbolic PDE to adaptive control of a benchmark parabolic PDE (a reaction-diffusion equation with a spatially-varying and unknown reaction coefficient). We prove global stability and asymptotic regulation of the plant state for a Lyapunov design of parameter adaptation. The key technical challenge of the result is handling the 2D nature of the gain kernels and proving that the target system with two distinct sources of perturbation terms, due to the parameter estimation error and due to the neural approximation error, is Lyapunov stable. To verify our theoretical result, we present simulations achieving calculation speedups up to 45x relative to the traditional finite difference solvers for every timestep in the simulation trajectory.
This paper develops a risk-aware net demand forecasting product for virtual power plants, which helps reduce the risk of high operation costs. At the training phase, a bilevel program for parameter ...estimation is formulated, where the upper level optimizes over the forecast model parameter to minimize the conditional value-at-risk (a risk metric) of operation costs. The lower level solves the operation problems given the forecast. Leveraging the specific structure of the operation problem, we show that the bilevel program is equivalent to a convex program when the forecast model is linear. Numerical results show that our approach effectively reduces the risk of high costs compared to the forecasting approach developed for risk-neutral decision makers.
Diabetic patients have a twofold to fourfold increased risk of cardiovascular disease. Despite a vast amount of research, the underlying mechanisms that predispose individuals with diabetes to the ...development of cardiovascular disease are unclear. To further our understanding of how diabetes promotes atherosclerosis, we have established, characterized, and manipulated a new model of hyperglycemia-induced atherosclerosis: the apolipoprotein E–deficient ( ApoE−/− ): Ins2+/Akita mouse. All mice were fed a standard chow diet. Male ApoE−/− : Ins2+/Akita mice developed chronic hyperglycemia, which significantly accelerated atherosclerosis. Female ApoE−/− : Ins2+/Akita mice presented hyperglycemia that normalized by 15 weeks of age. Despite the transient hyperglycemia, advanced atherosclerosis was observed at 15 weeks of age compared with ApoE−/− females. To better understand these differences, subsets of mice were castrated or ovariectomized at 5 weeks of age. Castrated ApoE−/− : Ins2+/Akita mice showed a reduction in blood glucose levels that correlated with the amelioration of atherosclerosis. Interestingly, castrated normoglycemic ApoE−/− mice developed larger atherosclerotic lesions than sham–operated on controls. Ovariectomized ApoE−/− : Ins2+/Akita mice presented chronic hyperglycemia, and atherosclerosis appeared to be advanced. We have characterized the distinctive sex-specific phenotypes exhibited by the ApoE−/− : Ins2+/Akita mouse model and present evidence for the action of sex hormones on pancreatic β-cell function and the vasculature that affect the regulation of blood glucose levels and the development of atherosclerosis. This model will provide a test bed to further delineate these effects.
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