常微分方程生物动力系统正性及耗散性研究方法

常微分方程生物动力系统解的正不变性和耗散性是对该类型动力行为刻画的先决条件,具有重要的基础作用.针对常微分方程生物动力系统这些共性问题的研究方法进行系统的归纳,分别对Kolmogorov型及非Kolmogorov型常微分方程生物动力系统典型实例的正不变性和耗散性研究进行全面总结,并应用于近年来生物动力系统前沿领域的相关研究.

关于非线性互惠共存生物动力系统解的性态

本文研究了非线性互惠共存生物动力系统在周期环境中解的性态，运用了比较原理，Ｂｒｏｕｗｅｒ不动点定理，锥域上的单调、强正、强凹算子等方法，得到周期解的存在唯一性，并证明了该周期解是全局一致渐近稳定的。

一类水域生物动力系统的定性分析

对由水域中浮游生物和为其提供营养的生物之间相互作用构成的动力系统进行了研究,得到了该系统在R2+内有唯一渐近稳定的平衡点且无周期轨道,做出了该系统轨线的全局结构,给出了所得结论的生物意义.

一类非线性周期种群系统的最优收获控制

研究一类具有周期系数和年龄结构的生物动力系统的最优收获问题 .应用冻结系数法和不动点原理讨论了状态系统的适定性 .借助法锥概念得到了控制问题的Pontryagin极值原理 。

Vibration control of pedestrian-bridge vertical dynamic coupling interaction based on biodynamic model

The human-induced vertical vibration serviceability of low-frequency and lightweight footbridges is studied based on the moving mass-spring-damper（MMSD） biodynamic model, and the mass damper（TMD） with different optimal model parameters being used to control the vertical vibration.First, the MMSD biodynamic model is employed to simulate the pedestrians, and the time-varying control equations of the vertical dynamic coupling system of the pedestrian-bridgeTMD are established with the consideration of pedestrianbridge dynamic interaction; and the equations are solved by using the Runge-Kutta-Felhberg integral method with variable step size. Secondly, the footbridge dynamic response is calculated under the model of pedestrian-structure dynamic interaction and the model of moving load when the pedestrian pace frequency is consistent with the natural frequency of footbridge. Finally, a comparative study and analysis are made on the control effects of the vertical dynamic coupling system in different optimal models of the TMD. The calculation results show that the pedestrian-bridge dynamic interaction cannot be ignored when the vertical human-induced vibration serviceability of low-frequency and light-weight footbridge is evaluated. The TMD can effectively reduce the vibration under the resonance of pedestrian-bridge, and TMD parameters are recommended for the determination by the Warburton optimization model.

庞国萍

庞国萍 女，广西陆川县人。现任玉林师范学院数学与计算机科学系主任，教授，理学博士，广西师范大学硕士研究生导师。主要从事非线性微分方程及生物动力系统的研究。近年来，主持和参与的科研项目12项，其中国家自然科学基金项目2项，广西自然科学基金项目1项，广西教育厅科研项目4项，院级科研项目5项。

Modeling water and carbon fluxes above summer maize field in North China Plain with back-propagation neural networks

In this work, datasets of water and carbon fluxes measured with eddy covariance technique above a summer maize field in the North China Plain were simulated with artificial neural networks (ANNs) to explore the fluxes responses to local environmental variables. The results showed that photosynthetically active radiation (PAR), vapor pressure deficit (VPD), air temperature (T) and leaf area index (LAI) were primary factors regulating both water vapor and carbon dioxide fluxes. Three-layer back-propagation neural networks (BP) could be applied to model fluxes exchange between cropland surface and atmosphere without using detailed physiological information or specific parameters of the plant.

Evaluation of Biological Assets： Problems and Solutions

The chief production elements of an agricultural enterprise are its biological assets and the choice and practical application of the evaluation methods, as the assets directly affect many aspects： decision making of economic character by the financial statement user, indicators of financial operation analysis, inter-comparison of sector enterprises, assessment of the company value and taxes on its economic activity, and statistical data of the agricultural sector. The authors have used the discounted cash flow （DCF） as an alternative method and a model of system dynamics. Such a system dynamics method has not been used for assessment of biological assets so far. In the operating process, the company acquires or loses possession of the resources. It is vital to analyze the resources to see whether they comply with the concept of the assets and the terms of recognition. It is necessary for the same company as well as for external users of financial statements to get true information about the business and the value of money. Biological assets may be recognized in the company＇s accounting only when it is predictable that future benefits associated with these assets will flow into the enterprise. It is also important that the fair value or the cost can be measured reliably.

Microbial Removal from Secondary Treated Wastewater Using a Hybrid System of Ultrafiltration and Reverse Osmosis

The efficiency of advanced membranes towards removal of general and specific microbes from wastewater was investigated. The treatment included a subsequent system of activated sludge, ultrafiltration （hollow fibre membranes with 100 kDa cut-off, and spiral wound membranes with 20 kDa cut-off）, and RO （reverse osmosis）. The removal evaluation of screened microbes present in treated wastewater showed that hollow fibre membrane rejected only 1 log （90% rejection） of the TPC （total microbial count）, TC （total coliforms）, and FC （faecal coliforms）. A higher effectiveness was observed with spiral wound, removing 2-3 logs （99%-99.9%） of TPC and complete rejection of TC and FC. The RO system was successful in total rejection of all received bacteria. The removal evaluation of inoculated specific types of bacteria showed that the hollow membranes removed 2 logs （99%） of inoculated E. coli （10^7-10^8 cfu/mL inoculum）, 2-3 logs （99%-99.9%） of Enterococus spp. （10^7-10^10 cfu/mL inoculum）, 1-2 logs （90%-99%） of Salmonella （10^8-10^10 cfu/mL inoculum） and 1-2 logs （90%-99%） of Shigella （10^5-10^6 cfu/mL inoculum）. The spiral wound was significantly efficient in rejecting further 3 logs of E. coil, 5 logs of Enterococus spp., 4 logs of Salmonella, and a complete rejection of all received bacteria was accomplished by RO membrane. The results indicate that Gram positive bacteria were removed much more efficiently compared to the Gram negative ones, the rationale behind such behaviour is based on cell walls elasticity.

Dynamical Criticality:Overview and Open Questions

Systems that exhibit complex behaviours are often found in a particular dynamical con- dition, poised between order and disorder. This observation is at the core of the so-called criticality hypothesis, which states that systems in a dynamical regime between order and disorder attain the highest level of computational capabilities and achieve an optimal trade-off between robustness and flexibility. Recent results in cellular and evolutionary biology, ueuroscience and computer science have revitalised the interest in the criticality hypothesis, emphasising its role as a viable candidate general law in adaptive complex systems. This paper provides an overview of the works on dynamical criticality that are -- To the best of our knowledge -- Particularly relevant for the criticality hypothesis. The authors review the main contributions concerning dynamics and information processing at the edge of chaos, and illustrate the main achievements in the study of critical dynamics in biological systems. Finally, the authors discuss open questions and propose an agenda for future work.

Recent advances in self-propelled particles

"Active" components can be introduced into a passive system to completely change its physical behavior from its typical behavior at thermodynamic equilibrium. To reveal the interaction mechanisms between individuals, researchers have designed unique self-propelled particles to mimic the collective behavior of biological systems. This review focuses on recent theoretical and experimental advances in the study of self-propelled particle systems and their individual and collective behaviors. The potential applications of active particles in chemical, biological and environmental sensing and single particle imaging are discussed.

Bifurcation behaviors analysis of a plankton model with multiple delays

A mathematical model describing the dynamics of toxin producing phytoplankton- zooplankton interaction with instantaneous nutrient recycling is proposed. We have explored the dynamics of plankton ecosystem with multiple delays; one due to gestation period in the growth of phytoplankton population and second due to the delay in toxin liberated by TPP. It is established that a sequence of Hopf bifurcations occurs at the interior equilibrium as the delay increases through its critical value. The direction of the Hopf bifurcation and the stability of the bifurcating periodic solutions are determined using the theory of normal form and center manifold. Meanwhile, effect of toxin on the stability of delayed plankton system is also established numerically. Finally, numerical simulations are carried out to support and supplement the analytical findings.

Progress in femtochemistry and femtobiology

Femtoscience offers a unique way to understand the dynamics in physics, chemistry and biology. This subject focuses on the process happening at femto-to pico-second time scale by femtosecond optical methods. Widely used in chemistry it reveals chemical reactions, including bond breaking, forming, and stretching, which happens at an ultrafast time scale. Femtoscience is also important in the biological system, for example, light harvesting system and vision system. Femtoscience in physics is also widely used, but it is not studied in this paper. Instead, we report new advances in femtochemistry and femtobiology, including structural dynamics, coherent control, enzyme function dynamics and hydration in the protein system. We also introduce attosecond science, focusing on electron dynamics at an extreme short time scale.

From foraging to autonoetic consciousness： The primal self as a consequence of embodied prospective foraging

The capacity to adapt to resource distributions by modulating the frequency of exploratory and exploitative behaviors is common across metazoans and is arguably a principal selective force in the evolution of cognition. Here we （I） review recent work investigating behavioral and biological commonalities between external foraging in space and internal foraging over envi- ronments specified by cognitive representations, and （2） explore the implications of these commonalities for understanding the origins of the self. Behavioural commonalities include the capacity for what is known as area-restricted search in the ecological literature： this is search focussed around locations where resources have been found in the past, but moving away from locations where few resources arc found, and capable of producing movement pattems mimicking L6vy flights. Area-restricted search shares a neural basis across metazoans, and these biological commonalities in vertebrates suggest an evolutionary homology be- tween external and internal foraging. Internal foraging, and in particular a form we call embodied prospective foraging, makes available additional capacities for prediction based on search through a cognitive representation of the external environment, and allows predictions about outcomes of possible future actions. We demonstrate that cognitive systems that use embodied prospec- tive foraging require a primitive sense of self, needed to distinguish actual from simulated action. This relationship has implica- tions for understanding the evolution of autonoetic consciousness and self-awareness.

Tectonomicrobiology:A new paradigm for geobiological research

Geomicrobiology is a sub-discipline of geobiology and emphasizes the interaction between microorganisms and their environment on Earth. There is a need to explicitly emphasize the biogeochemical processes performed by microorganisms associated with Earth's tectonic activities, especially under the framework of the modern theory of plate tectonics. Tectonomicrobiology aims to create a better synergy between microbial and active tectonic processes. This explicit synergy should also foster better communications between solid Earth scientists and life scientists in terms of holistic Earth system dynamics at both tectonic and micro-scales.

Stability analysis of combined project of fish, broiler and ducks： Dynamical system in imprecise environment

In this paper, we consider three species harvesting model and develop a solution proce- dure which is able to calculate the equilibrium points of the model where some biological parameters of the model are interval numbers. A parametric mathematical program is formulated to find the biological equilibrium of the model for different values of parame- ters. This interval-valued problem is converted into equivalent crisp model using interval operations. The main advantage of the proposed procedure is that we can present dif- ferent characteristics of the model in a single framework. Analytically, the existence of steady state and stabilities are looked into. Using mathematical software, the model is illustrated and the results are obtained and presented in tabular and graphical forms.

IMPULSIVE CONTROL IN MICROORGANISMS CONTINUOUS FERMENTATION

This work presents the nonlinear dynamical system of continuous fermentation from glycerol to 1,3-propanediol. The impulsive control scheme of continuous culture is intro- duced. By employing impulsive control, Lyapunov＇s method and comparison technique, sufficient conditions are established for the asymptotical stability and synchronization of the dynamical system of continuous fermentation. The upper bound of the impulse interval is also estimated. An example will illustrate the effectiveness of the results in Sec. 4.

MODELING AND PARAMETER IDENTIFICATION FOR MULTISTAGE SIMULATION OF MICROBIAL BIOCONVERSION IN BATCH CULTURE

The bioconversion of glycerol to 1,3-propanediol is a complex bioprocess. The item of product inhibition in the equation of Specific rate of cell growth is overlapped in [L. Wang, J. X. Ye, E. M. Feng and Z. L. Xiu, An improved model for multistage simula- tion of glycerol fermentation in batch culture and its parameter identification, Nonlinear Anal. Hybrid Syst. 3（4） （2009） 455462]. Therefore, in this work, the specific rate of cell growth is modified by the mechanism of multistage simulation of microbial bioconversion and the previous time-dependent model is converted to the autonomous standard form. The properties of the solutions for the nonlinear dynamic system are discussed and the identifiability of the parameters is proved. Finally the feasible optimization algorithm is constructed to find the optimal parameters for the system. Numerical result shows that the improved model with identified parameters can describe the batch culture better, compared with the previous results.