There is expounded the theory of＂gravitational＂ wave propagation from the volcano crater （magma） under changing density of magma mass inside the volcano. It was revealed that while the abruptly accelerated magma m...There is expounded the theory of＂gravitational＂ wave propagation from the volcano crater （magma） under changing density of magma mass inside the volcano. It was revealed that while the abruptly accelerated magma movement during starting period began eruption, the registered ＂gravitational＂ waves were being emitted and were propagating with the velocity greater than that of sound and seismic waves velocity. Alteration of ＂gravitational＂ waves velocity under the magma movement can be additional feature in prognosis of the start time of volcano eruption. The considered method might be effective when making up prognoses of underwater volcano eruption.展开更多
The roles of androgens on cardiovascular physiology and pathophysiology are controversial as both beneficial and detrimental effects have been reported. Although the reasons for this discrepancy are unclear, multiple ...The roles of androgens on cardiovascular physiology and pathophysiology are controversial as both beneficial and detrimental effects have been reported. Although the reasons for this discrepancy are unclear, multiple factors such as genetic and epigenetic variation, sex-specificity, hormone interactions, drug preparation and route of administration may contribute. Recently, growing evidence suggests that androgens exhibit beneficial effects on cardiovascular function though the mechanism remains to be elucidated. Endothelial cells （ECs） which line the interior surface of blood vessels are distributed throughout the circulatory system, and play a crucial role in cardiovascular function. Endothelial progenitor cells （EPCs） are considered an indispensable element for the reconstitution and maintenance of an intact endothelial layer. Endothelial dysfunction is regarded as an initiating step in development of atherosclerosis and cardiovascular diseases. The modulation of endothelial functions by androgens through either genornic or nongenomic signal pathways is one possible mechanism by which androgens act on the cardiovascular system. Obtaining insight into the mechanisms by which androgens affect EC and EPC functions will allow us to determine whether androgens possess beneficial effects on the cardiovascular system. This in turn may be critical in the prevention and therapy of cardiovascular diseases. This article seeks to review recent progress in androgen regulation of endothelial function, the sex-specificity of androgen actions, and its clinical applications in the cardiovascular system.展开更多
To simulate the dynamic responses of the multibody system with a floating base when the upper parts spread with a certain sequence and relative speed, the homogeneous matrix method is employed to model and simulate a ...To simulate the dynamic responses of the multibody system with a floating base when the upper parts spread with a certain sequence and relative speed, the homogeneous matrix method is employed to model and simulate a four-body system with a floating base and the motions are analyzed when the upper parts are spread sequentially or synchronously. The rolling, swaying and heaving temporal variations are obtained when the multibody system is under the conditions of the static water along with the wave loads and the mean wind loads or the single pulse wind loads, respectively. The moment variations of each joint under the single pulse wind load are also gained. The numerical results showed that the swaying of the floating base is almost not influenced by the spreading time or form when the upper parts spread sequentially or synchronously, while the rolling and the heaving mainly depend on the spreading time and forms. The swaying and heaving motions are influenced significantly by the mean wind loads. The single pulse wind load also has influences on the dynamic responses. The torque of joint 3 and joint 4 in the single pulse wind environment may be twice that in the windless environment when the system spreads with 60 s duration.展开更多
Chaotic genetic patchiness （CGP） refers to surprising patterns of spatial and temporal genetic structure observed in some marine species at a scale where genetic variation should be efficiently homogenized by gene f...Chaotic genetic patchiness （CGP） refers to surprising patterns of spatial and temporal genetic structure observed in some marine species at a scale where genetic variation should be efficiently homogenized by gene flow via larval dispersal. Here we review and discuss 4 mechanisms that could generate such unexpected patterns： selection, sweepstakes reproductive success, collective dispersal, and temporal shifts in local population dynamics. First, we review examples where genetic differentiation at specific loci was driven by diversifying selection, which was historically the first process invoked to explain CGP. Second, we turn to neutral demographic processes that may drive genome-wide effects, and whose effects on CGP may be enhanced when they act together. We discuss how sweepstakes reproductive success accelerates genetic drift and can thus generate genetic structure, provided that gene flow is not too strong. Collective dispersal is another mechanism whereby genetic structure can be maintained regardless of dispersal intensity, because it may prevent larval cohorts from becoming entirely mixed. Theoretical analyses of both the sweepstakes and the collective dispersal ideas are presented. Finally, we discuss an idea that has received less attention than the other ones just mentioned, namely temporal shifts in local population dynamics.展开更多
The transmission dynamics of Buruli ulcer （BU） largely depends on environmental changes. In this paper a deterministic model for the transmission of BU in fluctuating environments is proposed. The model incorporates...The transmission dynamics of Buruli ulcer （BU） largely depends on environmental changes. In this paper a deterministic model for the transmission of BU in fluctuating environments is proposed. The model incorporates periodicity in the disease transmission pathways and the Mycobacterium ulcerans density that are thought to vary seasonally. Two reproduction numbers, the time-averaged reproduction number [R0l and the basic reproduction number R0, are determined and compared. It is shown that the time-averaged reproduction underestimates the number of infections. Numerical simulations confirmed that if R0 〉 1 the infection is sustained seasonally. The model outcome suggests that environmental fluctuations should be taken into consideration in designing policies aimed at BU control and management.展开更多
The coupling effects of rib heights and fluid properties on turbulent convective heat transfer of kerosene flow through the rectangular duct on the ribbed bottom wall are studied numerically in this paper.The numerica...The coupling effects of rib heights and fluid properties on turbulent convective heat transfer of kerosene flow through the rectangular duct on the ribbed bottom wall are studied numerically in this paper.The numerical simulation is based on the ten components surrogate model of kerosene and the Reynolds average method combined with the re-normalized group(RNG)k-εturbulence model.The turbulent vortex structures and heat transfer characteristics of kerosene flowing over rectangular ribs of different heights are obtained.The results show that three dimensional vortices are generated by the ribs,and the vortices alter local flow significantly,leading to both enhanced and reduced convective heat transfer at different locations near the ribs.In addition,it is found that with the increase of rib height,the average Nusselt number and the wall friction factor on the ribbed wall also increase.For the present study,the maximum heat transfer enhancement rate of kerosene flow is 72.16%,and the ratio of rib-to-duct height is 0.75.展开更多
In this paper, we investigate the effects of variable viscosity and thermal conductivity on peristaltic flow of Jeffrey fluid in an asymmetric channel. The inclined magnetic field, viscous dissipation and Joule heatin...In this paper, we investigate the effects of variable viscosity and thermal conductivity on peristaltic flow of Jeffrey fluid in an asymmetric channel. The inclined magnetic field, viscous dissipation and Joule heating are also considered. Wave frame and long wave-length approximations are made to formulate the problem. Pressure gradient, pressure drop per wavelength, velocity and temperature profiles are calculated analytically and discussed graphically. Comparison is made with the previous work for reliability.展开更多
文摘There is expounded the theory of＂gravitational＂ wave propagation from the volcano crater （magma） under changing density of magma mass inside the volcano. It was revealed that while the abruptly accelerated magma movement during starting period began eruption, the registered ＂gravitational＂ waves were being emitted and were propagating with the velocity greater than that of sound and seismic waves velocity. Alteration of ＂gravitational＂ waves velocity under the magma movement can be additional feature in prognosis of the start time of volcano eruption. The considered method might be effective when making up prognoses of underwater volcano eruption.
基金The researches described in this article were partially supported by grants from the National Natural Science Foundation of China （No. 81570271 and 81400357） and NIH （UL1 RR024996）. We are very grateful to John R Lee （Assistant Professor of Medicine, Weill Comell Medical College, New York）, and Jeff J Zhu （Research Manager, Weill Comell Medical College, New York） for critical review of the article. The authors have nothing to disclosure.
文摘The roles of androgens on cardiovascular physiology and pathophysiology are controversial as both beneficial and detrimental effects have been reported. Although the reasons for this discrepancy are unclear, multiple factors such as genetic and epigenetic variation, sex-specificity, hormone interactions, drug preparation and route of administration may contribute. Recently, growing evidence suggests that androgens exhibit beneficial effects on cardiovascular function though the mechanism remains to be elucidated. Endothelial cells （ECs） which line the interior surface of blood vessels are distributed throughout the circulatory system, and play a crucial role in cardiovascular function. Endothelial progenitor cells （EPCs） are considered an indispensable element for the reconstitution and maintenance of an intact endothelial layer. Endothelial dysfunction is regarded as an initiating step in development of atherosclerosis and cardiovascular diseases. The modulation of endothelial functions by androgens through either genornic or nongenomic signal pathways is one possible mechanism by which androgens act on the cardiovascular system. Obtaining insight into the mechanisms by which androgens affect EC and EPC functions will allow us to determine whether androgens possess beneficial effects on the cardiovascular system. This in turn may be critical in the prevention and therapy of cardiovascular diseases. This article seeks to review recent progress in androgen regulation of endothelial function, the sex-specificity of androgen actions, and its clinical applications in the cardiovascular system.
基金the National Natural Science Foundation of China，Major State Basic Research Development Program of China （973 Program）
文摘To simulate the dynamic responses of the multibody system with a floating base when the upper parts spread with a certain sequence and relative speed, the homogeneous matrix method is employed to model and simulate a four-body system with a floating base and the motions are analyzed when the upper parts are spread sequentially or synchronously. The rolling, swaying and heaving temporal variations are obtained when the multibody system is under the conditions of the static water along with the wave loads and the mean wind loads or the single pulse wind loads, respectively. The moment variations of each joint under the single pulse wind load are also gained. The numerical results showed that the swaying of the floating base is almost not influenced by the spreading time or form when the upper parts spread sequentially or synchronously, while the rolling and the heaving mainly depend on the spreading time and forms. The swaying and heaving motions are influenced significantly by the mean wind loads. The single pulse wind load also has influences on the dynamic responses. The torque of joint 3 and joint 4 in the single pulse wind environment may be twice that in the windless environment when the system spreads with 60 s duration.
文摘Chaotic genetic patchiness （CGP） refers to surprising patterns of spatial and temporal genetic structure observed in some marine species at a scale where genetic variation should be efficiently homogenized by gene flow via larval dispersal. Here we review and discuss 4 mechanisms that could generate such unexpected patterns： selection, sweepstakes reproductive success, collective dispersal, and temporal shifts in local population dynamics. First, we review examples where genetic differentiation at specific loci was driven by diversifying selection, which was historically the first process invoked to explain CGP. Second, we turn to neutral demographic processes that may drive genome-wide effects, and whose effects on CGP may be enhanced when they act together. We discuss how sweepstakes reproductive success accelerates genetic drift and can thus generate genetic structure, provided that gene flow is not too strong. Collective dispersal is another mechanism whereby genetic structure can be maintained regardless of dispersal intensity, because it may prevent larval cohorts from becoming entirely mixed. Theoretical analyses of both the sweepstakes and the collective dispersal ideas are presented. Finally, we discuss an idea that has received less attention than the other ones just mentioned, namely temporal shifts in local population dynamics.
文摘The transmission dynamics of Buruli ulcer （BU） largely depends on environmental changes. In this paper a deterministic model for the transmission of BU in fluctuating environments is proposed. The model incorporates periodicity in the disease transmission pathways and the Mycobacterium ulcerans density that are thought to vary seasonally. Two reproduction numbers, the time-averaged reproduction number [R0l and the basic reproduction number R0, are determined and compared. It is shown that the time-averaged reproduction underestimates the number of infections. Numerical simulations confirmed that if R0 〉 1 the infection is sustained seasonally. The model outcome suggests that environmental fluctuations should be taken into consideration in designing policies aimed at BU control and management.
基金supported by the National Natural Science Foundation of China(Grant Nos.12072351 and 11872367).
文摘The coupling effects of rib heights and fluid properties on turbulent convective heat transfer of kerosene flow through the rectangular duct on the ribbed bottom wall are studied numerically in this paper.The numerical simulation is based on the ten components surrogate model of kerosene and the Reynolds average method combined with the re-normalized group(RNG)k-εturbulence model.The turbulent vortex structures and heat transfer characteristics of kerosene flowing over rectangular ribs of different heights are obtained.The results show that three dimensional vortices are generated by the ribs,and the vortices alter local flow significantly,leading to both enhanced and reduced convective heat transfer at different locations near the ribs.In addition,it is found that with the increase of rib height,the average Nusselt number and the wall friction factor on the ribbed wall also increase.For the present study,the maximum heat transfer enhancement rate of kerosene flow is 72.16%,and the ratio of rib-to-duct height is 0.75.
文摘In this paper, we investigate the effects of variable viscosity and thermal conductivity on peristaltic flow of Jeffrey fluid in an asymmetric channel. The inclined magnetic field, viscous dissipation and Joule heating are also considered. Wave frame and long wave-length approximations are made to formulate the problem. Pressure gradient, pressure drop per wavelength, velocity and temperature profiles are calculated analytically and discussed graphically. Comparison is made with the previous work for reliability.
