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
Mayer-Rokitansky-Kuster-Hauser Syndrome (MRKH) is a rare disease characterized by total or partial vagina agenesis, karyotype 46, XX with normal secondary sexual characters. Still, it is the second leading cause of pr...Mayer-Rokitansky-Kuster-Hauser Syndrome (MRKH) is a rare disease characterized by total or partial vagina agenesis, karyotype 46, XX with normal secondary sexual characters. Still, it is the second leading cause of primary amenorrhea. The absence of obvious signs and symptoms often causes the syndrome to be diagnosed only after puberty. The case presented here highlights exactly this difficulty of early diagnosis, which meets the objective of the study, and is precisely to provide reliable material that facilitates the diagnosis and management of patients with MRKH syndrome.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.
文摘Mayer-Rokitansky-Kuster-Hauser Syndrome (MRKH) is a rare disease characterized by total or partial vagina agenesis, karyotype 46, XX with normal secondary sexual characters. Still, it is the second leading cause of primary amenorrhea. The absence of obvious signs and symptoms often causes the syndrome to be diagnosed only after puberty. The case presented here highlights exactly this difficulty of early diagnosis, which meets the objective of the study, and is precisely to provide reliable material that facilitates the diagnosis and management of patients with MRKH syndrome.
