Variability in cardiovascular spectra was first described by Stephan Hales in 1733.Traube and Hering initially noted respirophasic variation of the arterial pressure waveform in 1865 and Sigmund Mayer noted a lower fr...Variability in cardiovascular spectra was first described by Stephan Hales in 1733.Traube and Hering initially noted respirophasic variation of the arterial pressure waveform in 1865 and Sigmund Mayer noted a lower frequency oscillation of the same in anesthetized rabbits in 1876.Very low frequency oscillations were noted by Barcroft and Nisimaru in 1932,likely representing vasogenic autorhythmicity.While the origins of Traube Hering and very low frequency oscillatory variability in cardiovascular spectra are well described,genesis mechanisms and functional significance of Mayer waves remain in controversy.Various theories have posited baroreflex and central supraspinal mechanisms for genesis of Mayer waves.Several studies have demonstrated the persistence of Mayer waves following high cervical transection,indicating a spinal capacity for genesis of these oscillations.We suggest a general tendency for central sympathetic neurons to oscillate at the Mayer wave frequency,the presence of multiple Mayer wave oscillators throughout the brainstem and spinal cord,and possible contemporaneous genesis by baroreflex and vasomotor mechanisms.展开更多
We study graph weights which naturally occur in Mayer’s theory and Ree-Hoover’s theory for the virial expansion in the context of an imperfect gas. We pay particular attention to the Mayer weight and Ree-Hoover weig...We study graph weights which naturally occur in Mayer’s theory and Ree-Hoover’s theory for the virial expansion in the context of an imperfect gas. We pay particular attention to the Mayer weight and Ree-Hoover weight of a 2-connected graph in the case of the hard-core continuum gas in one dimension. These weights are calculated from signed volumes of convex polytopes associated with the graph. In the present paper, we use the method of graph homomorphisms, to develop other explicit formulas of Mayer weights and Ree-Hoover weights for infinite families of 2-connected graphs.展开更多
The virial expansion, in statistical mechanics, makes use of the sums of the Mayer weight of all 2-connected graphs on n vertices. We study the Second Mayer weight ωM(c) and the Ree-Hoover weight ωRH(c) of a 2-conne...The virial expansion, in statistical mechanics, makes use of the sums of the Mayer weight of all 2-connected graphs on n vertices. We study the Second Mayer weight ωM(c) and the Ree-Hoover weight ωRH(c) of a 2-connected graph c which arise from the hard-core continuum gas in one dimension. These weights are computed using signed volumes of convex polytopes naturally associated with the graph c. In the present work, we use the method of graph homomorphisms, to give new formulas of Mayer and Ree-Hoover weights for special infinite families of 2-connected graphs.展开更多
Karl Mayer公司在ITMA’91上展出了9种新近改进的经编机,还有一个弹性纱整经车间和另一个长丝纱整经车间,使经轴准备装置的系列趋于完备.经编的各种应用以资料、装饰花样及产品的方式被展现出来.主要产品有高质量花边、窗帘及服装用超...Karl Mayer公司在ITMA’91上展出了9种新近改进的经编机,还有一个弹性纱整经车间和另一个长丝纱整经车间,使经轴准备装置的系列趋于完备.经编的各种应用以资料、装饰花样及产品的方式被展现出来.主要产品有高质量花边、窗帘及服装用超细纤维经编织物.另外还有汽车内用装饰织物、包装袋及工业用纺织品.在Karl Mayer经编机上,使用CNC技术的花型控制系统几乎完全取代了所有的常规系统.目前。展开更多
文摘Variability in cardiovascular spectra was first described by Stephan Hales in 1733.Traube and Hering initially noted respirophasic variation of the arterial pressure waveform in 1865 and Sigmund Mayer noted a lower frequency oscillation of the same in anesthetized rabbits in 1876.Very low frequency oscillations were noted by Barcroft and Nisimaru in 1932,likely representing vasogenic autorhythmicity.While the origins of Traube Hering and very low frequency oscillatory variability in cardiovascular spectra are well described,genesis mechanisms and functional significance of Mayer waves remain in controversy.Various theories have posited baroreflex and central supraspinal mechanisms for genesis of Mayer waves.Several studies have demonstrated the persistence of Mayer waves following high cervical transection,indicating a spinal capacity for genesis of these oscillations.We suggest a general tendency for central sympathetic neurons to oscillate at the Mayer wave frequency,the presence of multiple Mayer wave oscillators throughout the brainstem and spinal cord,and possible contemporaneous genesis by baroreflex and vasomotor mechanisms.
文摘We study graph weights which naturally occur in Mayer’s theory and Ree-Hoover’s theory for the virial expansion in the context of an imperfect gas. We pay particular attention to the Mayer weight and Ree-Hoover weight of a 2-connected graph in the case of the hard-core continuum gas in one dimension. These weights are calculated from signed volumes of convex polytopes associated with the graph. In the present paper, we use the method of graph homomorphisms, to develop other explicit formulas of Mayer weights and Ree-Hoover weights for infinite families of 2-connected graphs.
文摘The virial expansion, in statistical mechanics, makes use of the sums of the Mayer weight of all 2-connected graphs on n vertices. We study the Second Mayer weight ωM(c) and the Ree-Hoover weight ωRH(c) of a 2-connected graph c which arise from the hard-core continuum gas in one dimension. These weights are computed using signed volumes of convex polytopes naturally associated with the graph c. In the present work, we use the method of graph homomorphisms, to give new formulas of Mayer and Ree-Hoover weights for special infinite families of 2-connected graphs.