The robustness and breakup of spiral wave in a two-dimensional lattice networks of neurons are investigated. The effect of small- world type connection is often simplified with local regular connection and the long-ra...The robustness and breakup of spiral wave in a two-dimensional lattice networks of neurons are investigated. The effect of small- world type connection is often simplified with local regular connection and the long-range connection with certain probability. The network effect on the development of spiral wave can be better described by local regular connection and changeable long-range connection probability than fixed long-range connection probability because the long-range probability could be changeable in realistic biological system. The effect from the changeable probability for long-range connection is simplified by multiplicative noise. At first, a stable rotating spiral wave is developed by using appropriate initial values, parameters and no-flux boundary conditions, and then the effect of networks is investigated. Extensive numerical studies show that spiral wave keeps its alive and robust when the intensity of multiplicative noise is below a certain threshold, otherwise, the breakup of spiral wave occurs. A statistical factor of synchronization in two-dimensional array is defined to study the phase transition of spiral wave by checking the membrane potentials of all neurons corresponding to the critical parameters(the intensity of noise or forcing current)in the curve for factor of synchronization. The Hindmarsh-Rose model is investigated, the Hodgkin-Huxley neuron model in the presence of the channel noise is also studied to check the model independence of our conclusions. And it is found that breakup of spiral wave is easier to be induced by the multiplicative noise in presence of channel noise.展开更多
目的基于特征图谱整体性表征中药组分群的优势,研究玳玳黄酮滴丸药效组分群的体外溶出行为,评价组分群的同步释药情况。方法建立HPLC特征图谱法及特征活性成分测定法,并采用转篮法评价玳玳黄酮滴丸组分群在4种不同p H值溶出介质(p H 1....目的基于特征图谱整体性表征中药组分群的优势,研究玳玳黄酮滴丸药效组分群的体外溶出行为,评价组分群的同步释药情况。方法建立HPLC特征图谱法及特征活性成分测定法,并采用转篮法评价玳玳黄酮滴丸组分群在4种不同p H值溶出介质(p H 1.2的盐酸溶液、p H 4.5的醋酸-醋酸钠缓冲液、p H 6.8的磷酸盐缓冲液和蒸馏水)中的溶出度及释药特性,分别运用单指数方程模型、威布尔方程模型、对数分布方程模型拟合溶出曲线。结果玳玳黄酮滴丸特征图谱中的9个共有峰成分溶出曲线的相似因子(f2)均大于50,且特征药效成分新橙皮苷及柚皮苷溶出曲线的f2为94.86,表明玳玳黄酮滴丸组分群具有相似的溶出曲线及同步释药特性,特征图谱的9个共有峰活性成分组分群较符合威布尔方程模型的溶出机制。结论所建立的基于特征图谱评价中药有效部位制备的玳玳黄酮滴丸组分群的溶出及同步释药特性的方法可行,为提高其内在质量评价奠定了实验基础。展开更多
In this article, we propose a novel, multilevel, dynamic factor model, to determine endogenously clustered regions for the investigation of regional clustering and synchronization of provincial business fluctuations i...In this article, we propose a novel, multilevel, dynamic factor model, to determine endogenously clustered regions for the investigation of regional clustering and synchronization of provincial business fluctuations in China. The parameter identification and model estimation was conducted using the Markov Chain Monte Carlo method. We then conducted an empirical study of the provincial business fluctuations in China(31 Chinese provinces are considered except Hong Kong, Macao, and Taiwan due to the data unavailability), which were sampled from January 2000 to December 2015. Our results indicated that these provinces could be clustered into four regions: leading, coincident, lagging, and overshooting. In comparison with traditional geographical divisions, this novel clustering into four regions enabled the regional business cycle synchronization to be more accurately captured. Within the four regional clusters it was possible to identify substantial heterogeneities among regional business cycle fluctuations, especially during the periods of the 2008 financial crisis and the ‘four-trillion economic stimulus plan'.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. 10747005, 30670529 and 10875049)the Key Project of MOE (Grant No. 108096)the Natural Science of Lanzhou University of Technology (Grant No. Q200706)
文摘The robustness and breakup of spiral wave in a two-dimensional lattice networks of neurons are investigated. The effect of small- world type connection is often simplified with local regular connection and the long-range connection with certain probability. The network effect on the development of spiral wave can be better described by local regular connection and changeable long-range connection probability than fixed long-range connection probability because the long-range probability could be changeable in realistic biological system. The effect from the changeable probability for long-range connection is simplified by multiplicative noise. At first, a stable rotating spiral wave is developed by using appropriate initial values, parameters and no-flux boundary conditions, and then the effect of networks is investigated. Extensive numerical studies show that spiral wave keeps its alive and robust when the intensity of multiplicative noise is below a certain threshold, otherwise, the breakup of spiral wave occurs. A statistical factor of synchronization in two-dimensional array is defined to study the phase transition of spiral wave by checking the membrane potentials of all neurons corresponding to the critical parameters(the intensity of noise or forcing current)in the curve for factor of synchronization. The Hindmarsh-Rose model is investigated, the Hodgkin-Huxley neuron model in the presence of the channel noise is also studied to check the model independence of our conclusions. And it is found that breakup of spiral wave is easier to be induced by the multiplicative noise in presence of channel noise.
文摘目的基于特征图谱整体性表征中药组分群的优势,研究玳玳黄酮滴丸药效组分群的体外溶出行为,评价组分群的同步释药情况。方法建立HPLC特征图谱法及特征活性成分测定法,并采用转篮法评价玳玳黄酮滴丸组分群在4种不同p H值溶出介质(p H 1.2的盐酸溶液、p H 4.5的醋酸-醋酸钠缓冲液、p H 6.8的磷酸盐缓冲液和蒸馏水)中的溶出度及释药特性,分别运用单指数方程模型、威布尔方程模型、对数分布方程模型拟合溶出曲线。结果玳玳黄酮滴丸特征图谱中的9个共有峰成分溶出曲线的相似因子(f2)均大于50,且特征药效成分新橙皮苷及柚皮苷溶出曲线的f2为94.86,表明玳玳黄酮滴丸组分群具有相似的溶出曲线及同步释药特性,特征图谱的9个共有峰活性成分组分群较符合威布尔方程模型的溶出机制。结论所建立的基于特征图谱评价中药有效部位制备的玳玳黄酮滴丸组分群的溶出及同步释药特性的方法可行,为提高其内在质量评价奠定了实验基础。
基金Under the auspices of the National Natural Science Foundation of China(No.71371160)the Program for Changjiang Youth Scholars(No.Q2016131)the Program for New Century Excellent Talents in University(No.NCET-13-0509)
文摘In this article, we propose a novel, multilevel, dynamic factor model, to determine endogenously clustered regions for the investigation of regional clustering and synchronization of provincial business fluctuations in China. The parameter identification and model estimation was conducted using the Markov Chain Monte Carlo method. We then conducted an empirical study of the provincial business fluctuations in China(31 Chinese provinces are considered except Hong Kong, Macao, and Taiwan due to the data unavailability), which were sampled from January 2000 to December 2015. Our results indicated that these provinces could be clustered into four regions: leading, coincident, lagging, and overshooting. In comparison with traditional geographical divisions, this novel clustering into four regions enabled the regional business cycle synchronization to be more accurately captured. Within the four regional clusters it was possible to identify substantial heterogeneities among regional business cycle fluctuations, especially during the periods of the 2008 financial crisis and the ‘four-trillion economic stimulus plan'.
