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Khoja, Leila, Christy Mitchinson, Damien Brown, Cong Zhou, Karen Morris, Derek O'Reilly, Rahul Deshpande, et al. "Pancreatic circulating tumor cells: Where are they?" Journal of Clinical Oncology 30, no. 15_suppl (May 20, 2012): e21037-e21037. http://dx.doi.org/10.1200/jco.2012.30.15_suppl.e21037.
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e21037 Background: We previously demonstrated that circulating tumor cell (CTC) numbers in advanced pancreatic carcinoma were low in contrast to other epithelial carcinomas. We hypothesized that pancreatic CTCs may sequest in the liver and conceived a study to explore CTC number in the peripheral and portal circulations of patients undergoing Whipple’s surgery. Methods: Seventeen patients undergoing Whipple’s surgery were recruited prospectively after informed written consent. Blood was collected intra-operatively from the portal vein prior to tumor mobilization and from the peripheral circulation. Paired samples were analysed for CTC number (CellSearch system, Veridex, USA), and M30/M65 biomarkers of cell death. Results: Of 17 patients 6 had cholangiocarcinomas and 11 had pancreatic adenocarcinomas (5 inoperable). CTC number in the portal circulation was consistently higher than in the peripheral circulation. All patients with cholangiocarcinoma had no CTCs in the peripheral circulation but two patients had 139 and 21 CTCs in the portal circulation. Five patients with pancreatic carcinoma had no CTCs in the peripheral circulation but 1 CTC in 2 patients, 4 CTCs in 2 patients and 32 and 731 CTCs were seen in 2 other patients in the portal circulation. Five patients had no CTCs in both circulations and the remaining patient had 1 CTC in the peripheral circulation and 4 CTCs in the portal circulation. Where present, circulating tumour microemboli were detected in the portal circulation only. M65 levels were higher in the portal circulation indicating higher levels of cell death. M30 levels did not differ significantly between circulations but appeared to correlate with portal CTC number. Conclusions: This is the first study to enumerate CTCs in peripheral and portal circulations in pancreato-biliary carcinomas. Higher CTC numbers are present in the portal circulation suggesting CTC sequestration in the liver. Five patients with pancreatic cancer (2 of whom were inoperable) had no CTCs in either circulation, a finding consistent with the poor vascularity and dense stromal characteristics of this carcinoma. Nonetheless the portal circulation may be a potential source for CTC characterisation including genomic analysis to further define tumor biology.
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Miao, Yucong, Shuhua Liu, Yijia Zheng, Shu Wang, and Bicheng Chen. "Numerical Study of the Effects of Topography and Urbanization on the Local Atmospheric Circulations over the Beijing-Tianjin-Hebei, China." Advances in Meteorology 2015 (2015): 1–16. http://dx.doi.org/10.1155/2015/397070.
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The effects of the topography and urbanization on the local atmospheric circulations over the Beijing-Tianjin-Hebei (BTH) region were studied by the weather research and forecasting (WRF) model, as well as the interactions among these local atmospheric circulations. It was found that, in the summer day time, the multiscale thermally induced local atmospheric circulations may exist and interact in the same time over the BTH region; the topography played a role in the strengthening of the sea breeze circulations; after sunset, the inland progress of sea breeze was slowed down by the opposite mountain breeze; when the land breeze circulation dominated the Bohai bay, the mountain breeze circulation can couple with the land breeze circulation to form a large circulation ranging from the coastline to the mountains. And the presence of cities cannot change the general state of the sea-land breeze (SLB) circulation and mountain-valley breeze (MVB) circulation but acted to modify these local circulations slightly. Meanwhile, the development of the urban heat island (UHI) circulation was also strongly influenced by the nearby SLB circulation and MVB circulation.
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Plesca, Elina, Verena Grützun, and Stefan A. Buehler. "How Robust Is the Weakening of the Pacific Walker Circulation in CMIP5 Idealized Transient Climate Simulations?" Journal of Climate 31, no. 1 (December 8, 2017): 81–97. http://dx.doi.org/10.1175/jcli-d-17-0151.1.
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Abstract The tropical overturning circulations are likely weakening under increased CO2 forcing. However, insufficient understanding of the circulations’ dynamics diminishes the full confidence in such a response. Based on a CMIP5 idealized climate experiment, this study investigates the changes in the Pacific Walker circulation under anthropogenic forcing and the sensitivity of its weakening response to internal variability, general circulation model (GCM) configuration, and indexing method. The sensitivity to internal variability is analyzed by using a 68-member ensemble of the MPI-ESM-LR model, and the influence of model physics is analyzed by using the 28-member CMIP5 ensemble. Three simple circulation indices—based on mean sea level pressure, 500-hPa vertical velocity, and 200-hPa velocity potential—are computed for each member of the two ensembles. The study uses the output of the CMIP5 idealized transient climate simulations with 1% yr−1 CO2 increase from preindustrial level, and investigates the detected circulation response until the moment of CO2 doubling (70 yr). Depending on the indexing method, it is found that 50%–93% of the MPI-ESM-LR and 54%–75% of the CMIP5 ensemble members project significant negative trends in the circulation’s intensity. This large spread in the ensembles reduces the confidence that a weakening circulation is a robust feature of climate change. Furthermore, the similar magnitude of the spread in both ensembles shows that the Walker circulation response is strongly influenced by natural variability, even over a 70-yr period.
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Leete, Art, Elo-Hanna Seljamaa, and Laur Vallikivi. "A Few Impressions and Reflections American Anthropological Association: 109th Annual Meeting. November 17–21, 2010. New Orleans." Folklore: Electronic Journal of Folklore 47 (2011): 185–90. http://dx.doi.org/10.7592/fejf2011.47.circulation.
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Jin, Xin, Shiru Huang, and Xue Lei. "Research on the Impact Mechanism of Green Innovation in Marine Science and Technology Enabling Dual Economic Circulations." Sustainability 16, no. 19 (September 27, 2024): 8421. http://dx.doi.org/10.3390/su16198421.
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Currently, accelerating the construction of a new development pattern with dual economic circulations is strategically significant for enhancing the autonomy and sustainability of China’s economic development. First of all, this paper, from the perspective of green innovation in marine science and technology, measures its efficiency using the SBM super-efficiency model. Then, a coupling coordination model calculates the coordination degree of dual economic circulations after measuring the domestic and international economic circulations based on the TOPSIS method. Secondly, a two-way fixed effects model is employed to examine the impact of green innovation in marine science and technology on domestic economic circulation, international economic circulation, and dual economic circulations. The study finds that green innovation in marine science and technology effectively promotes domestic economic circulation, international economic circulation, and the dual economic circulations. Additionally, green innovation in marine science and technology mitigates the impact of inter-regional resource misalignment on domestic economic circulation and influences international economic circulation by promoting the high-quality development of the marine economy. Finally, it is discovered that green innovation in marine science and technology exhibits a single-threshold heterogeneous effect on domestic economic circulation and international economic circulation.
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Waalewijn, R. A. "Problemen met de circulatie (C: Circulation)." Bijblijven 19, no. 7 (July 2003): 287–95. http://dx.doi.org/10.1007/bf03059727.
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Cunningham, Stuart A. "Southern Ocean circulation." Archives of Natural History 32, no. 2 (October 2005): 265–80. http://dx.doi.org/10.3366/anh.2005.32.2.265.
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The Discovery Investigations of the 1930s provided a compelling description of the main elements of the Southern Ocean circulation. Over the intervening years, this has been extended to include ideas on ocean dynamics based on physical principles. In the modern description, the Southern Ocean has two main circulations that are intimately linked: a zonal (west-east) circumpolar circulation and a meridional (north-south) overturning circulation. The Antarctic Circumpolar Current transports around 140 million cubic metres per second west to east around Antarctica. This zonal circulation connects the Atlantic, Indian and Pacific Oceans, transferring and blending water masses and properties from one ocean basin to another. For the meridional circulation, a key feature is the ascent of waters from depths of around 2,000 metres north of the Antarctic Circumpolar Current to the surface south of the Current. In so doing, this circulation connects deep ocean layers directly to the atmosphere. The circumpolar zonal currents are not stable: meanders grow and separate, creating eddies and these eddies are critical to the dynamics of the Southern Ocean, linking the zonal circumpolar and meridional circulations. As a result of this connection, a global three-dimensional ocean circulation exists in which the Southern Ocean plays a central role in regulating the Earth's climate.
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Lenz, T., G. D. James, J. H. Laragh, and J. E. Sealey. "Prorenin secretion from human placenta perfused in vitro." American Journal of Physiology-Endocrinology and Metabolism 260, no. 6 (June 1, 1991): E876—E882. http://dx.doi.org/10.1152/ajpendo.1991.260.6.e876.
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We examined whether renin (prorenin plus renin) is secreted from the human placenta into the maternal or fetal circulation and compared the secretion rate to that of human chorionic gonadotropin (hCG), progesterone, and estradiol. While estradiol and progesterone passed into both circulations, renin (mostly prorenin) and hCG were secreted predominantly into the maternal circulation. To examine if prorenin passed from the maternal to the fetal circulation and vice versa, we perfused both circuits separately with exogenous recombinant human prorenin. No prorenin passed from maternal to fetal circulations, but a small amount (less than 10%) slowly passed from fetal to maternal, beginning 15 min after the addition of prorenin. Exogenous prorenin was not converted to renin in either circulation. Perfusate total renin had close to 10% active renin, whereas that of tissue extracts was closer to 50%. In conclusion, the results are consistent with some tissue activation of prorenin, either in vitro or in vivo, but no activation in the maternal or fetal circulations. The human placenta may secrete prorenin into the maternal but not into the fetal circulation. The possibility that the placenta may secrete a small amount of active renin into the maternal circulation was not ruled out.
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Aquino-Martínez, Lourdes P., Arturo I. Quintanar, Carlos A. Ochoa-Moya, Erika Danaé López-Espinoza, David K. Adams, and Aron Jazcilevich-Diamant. "Urban-Induced Changes on Local Circulation in Complex Terrain: Central Mexico Basin." Atmosphere 12, no. 7 (July 14, 2021): 904. http://dx.doi.org/10.3390/atmos12070904.
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Land use land cover (LULC) significantly impacts local circulation in the Mexico Basin, particularly wind field circulations such as gap winds, convergence lines, and thermally induced upslope/downslope wind. A case study with a high-pressure system over the Mexico Basin isolates the influence of large-scale synoptic forcing. Numerical simulations reveal a wind system composed of meridional circulation and a zonal component. Thermal pressure gradients between the Mexico basin and its colder surroundings create near-surface convergence lines as part of the meridional circulation. Experiments show that the intensity and organization of meridional circulations and downslope winds increase when LULC changes from natural and cultivated land to urban. Zonal circulation exhibits a typical circulation pattern with the upslope flow and descending motion in the middle of the basin. Large values of moist static energy are near the surface where air parcels pick up energy from the surface either as fluxes of enthalpy or latent heat. Surface heat fluxes and stored energy in the ground are drivers of local circulation, which is more evident in zonal circulation patterns.
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Hickey, Joanne V. "Cerebral Circulation Demystified." AACN Advanced Critical Care 2, no. 4 (November 1, 1991): 657–64. http://dx.doi.org/10.4037/15597768-1991-4005.
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Basic anatomic and physiologic concepts related to cerebral circulation are summarized. The arterial blood supply is traced from its origins to the major divisions of anterior and posterior circulation. The circle of Willis, the major arterial vessels and territories, and the peculiarities of the cerebral venous circulation are discussed. Finally, concepts of cerebral circulations are applied to clinical practice to assist the nurse in accurately assessing, monitoring, and predicting human responses to alterations in cerebral blood supply
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Walker, Christopher C., and Tapio Schneider. "Eddy Influences on Hadley Circulations: Simulations with an Idealized GCM." Journal of the Atmospheric Sciences 63, no. 12 (December 2006): 3333–50. http://dx.doi.org/10.1175/jas3821.1.
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An idealized GCM is used to investigate how the strength and meridional extent of the Hadley circulation depend on the planet radius, rotation rate, and thermal driving. Over wide parameter ranges, the strength and meridional extent of the Hadley circulation display clear scaling relations with regime transitions, which are not predicted by existing theories of axisymmetric Hadley circulations. For example, the scaling of the strength as a function of the radiative-equilibrium equator-to-pole temperature contrast exhibits a regime transition corresponding to a regime transition in scaling laws of baroclinic eddy fluxes. The scaling of the strength of the cross-equatorial Hadley cell as a function of the latitude of maximum radiative-equilibrium temperature exhibits a regime transition from a regime in which eddy momentum fluxes strongly influence the strength to a regime in which the influence of eddy momentum fluxes is weak. Over a wide range of flow parameters, albeit not always, the Hadley circulation strength is directly related to the eddy momentum flux divergence at the latitude of the streamfunction extremum. Simulations with hemispherically symmetric thermal driving span circulations with local Rossby numbers in the horizontal upper branch of the Hadley circulation between 0.1 and 0.8, indicating that neither nonlinear nearly inviscid theories, valid for Ro → 1, nor linear theories, valid for Ro → 0, of axisymmetric Hadley circulations can be expected to be generally adequate. Nonlinear theories of axisymmetric Hadley circulations may account for aspects of the circulation when the maximum radiative-equilibrium temperature is displaced sufficiently far away from the equator, which results in cross-equatorial Hadley cells with nearly angular momentum-conserving upper branches. The dependence of the Hadley circulation on eddy fluxes, which are themselves dependent on extratropical circulation characteristics such as meridional temperature gradients, suggests that tropical circulations depend on the extratropical climate.
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Ryu, Young-Hee, and Jong-Jin Baik. "Daytime Local Circulations and Their Interactions in the Seoul Metropolitan Area." Journal of Applied Meteorology and Climatology 52, no. 4 (April 2013): 784–801. http://dx.doi.org/10.1175/jamc-d-12-0157.1.
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AbstractDaytime local circulations and their interactions in the Seoul, South Korea, metropolitan area are investigated using a high-resolution mesoscale model. It is found that the urban-breeze circulation interacts strongly with other local circulations, such as sea-breeze, cross-valley, and river-breeze circulations. Inland penetration of the sea breeze is retarded in the morning when moving over the coastal urban area because of the increased surface roughness but is accelerated in the afternoon after passing through the urban area as a result of the landward-convergent flow induced by urban heat islands in the inland urban areas. In the valley region, the cross-valley circulation prevails in the morning and the urban-breeze circulation prevails in the afternoon. The mountainside urban-breeze circulation weakens because of the cross-valley circulation in the opposite direction. On the other hand, the plainside urban-breeze circulation away from the mountain increases in strength as a result of the combined effect of heating from the urban surface and subsidence heating associated with the cross-valley circulation. This strengthened urban breeze acts to inhibit penetration of the sea breeze farther inland, causing the sea breeze to stagnate in Seoul. In the vicinity of the Han River, convergence zones with strong updrafts are formed as a result of the interaction between the urban breeze and the river breeze. When the sea-breeze front encounters the strong updrafts, the vertical velocity of the front at the intersection points increases.
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Wei, Liu, Zheng Xueli, Li Yunhan, Li Xia, and Liu Li. "Research on the impact effect of multimodal transport on domestic and international dual circulation: Evidence from China’s railway and water transport." PLOS One 20, no. 4 (April 25, 2025): e0319982. https://doi.org/10.1371/journal.pone.0319982.
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As an important part of the modern integrated transportation system, multimodal transport can promote changes in the transportation structure and serve as a crucial lever for upgrading the logistics industry and promoting domestic and international economic and trade development. Based on panel data from 31 provinces in China from 2017 to 2023, a fixed-effects model was constructed to empirically test the mechanism and impact of multimodal transport on domestic and international dual circulation. The findings reveal that the development of multimodal transport has a positive effect on both domestic and international circulations, with a more significant impact on the latter. Specifically, waterway multimodal transport significantly promotes both circulations, while railway multimodal transport only significantly affects the domestic circulation. Furthermore, the impact of multimodal transport on domestic and international dual circulations exhibits notable regional heterogeneity, with multimodal transport in eastern regions having a stronger effect on international circulations and that in central regions having a stronger effect on domestic circulations. This paper analyzes the theory of the multimodal transport’s impact on domestic and international dual circulation, provides a practical basis and reference for further research on the development of multimodal transport in relation to domestic and international dual circulation.
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Yokoyama, Chie, Edward J. Zipser, and Chuntao Liu. "TRMM-Observed Shallow versus Deep Convection in the Eastern Pacific Related to Large-Scale Circulations in Reanalysis Datasets." Journal of Climate 27, no. 14 (July 10, 2014): 5575–92. http://dx.doi.org/10.1175/jcli-d-13-00315.1.
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Abstract Over the eastern Pacific, recent studies have shown that a shallow large-scale meridional circulation with its return flow just above the boundary layer coexists with a deep Hadley circulation. This study examines how the vertical structure of large-scale circulations is related to satellite-observed individual precipitation properties over the eastern Pacific in boreal autumn. Three reanalysis datasets are used to describe differences in their behavior. The results are compared among reanalyses and three distinctly different convection periods, which are defined according to their radar echo depths. Shallow and deep circulations are shown to often coexist for each of the three periods, resulting in the multicell circulation structure. Deep (shallow) circulations preferentially appear in the mostly deep (shallow) convection period of radar echo depths. Thus, depth of convection basically corresponds to which circulation branch is dominant. This anticipated relationship between the circulation structure and depths of convection is common in all three reanalyses. Notable differences among reanalyses are found in the mid- to upper troposphere in either the time-mean state or the composite analysis based on the convection periods. Reanalyses have large variations in characteristics associated with deep circulations such as the upper-tropospheric divergence and outflows and the midlevel inflows, which are consistent with their different profiles of latent heating in the mid- to upper troposphere. On the other hand, discrepancies in shallow circulations and shallow convection are also found, but they are not as large as those in deep ones.
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Kim, Hye-Ryeom, Kyung-Ja Ha, Suyeon Moon, Hyoeun Oh, and Sahil Sharma. "Impact of the Indo-Pacific Warm Pool on the Hadley, Walker, and Monsoon Circulations." Atmosphere 11, no. 10 (September 24, 2020): 1030. http://dx.doi.org/10.3390/atmos11101030.
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The Indo-Pacific warm pool (IPWP) is enclosed by a 28 °C isotherm and plays a vital role in controlling atmospheric circulations. However, the effects of changes in regional warm pool sea surface temperatures (SSTs) remain unexplored. We divided the IPWP into the Indian and Pacific sectors and distinguished their responses to natural variability and global warming. Furthermore, we examined the impacts of the interannual variability (IAV) in warm pool SST on the tropical Hadley, Walker, and monsoon circulations. The Hadley circulation was affected by warm pool SST warming, i.e., warmer SSTs over the warm pool strengthened the upward branch of Hadley circulation, whereas the downward branch was respectively weakened and strengthened in the Northern and Southern Hemispheres. Walker circulation was strengthened (weakened) in the warming (natural) mode. Consequently, the Walker circulation is weakened since the natural variability of warm pool SST plays a more dominant role rather than the warming trend of SSTs over the warm pool. Furthermore, our analysis displays that warm pool warming has little impact on the monsoon circulation. Our findings highlight the different roles of the IAV of warm pool regions in each tropical circulation as part of the warming trend and natural variability.
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Wills, Robert C., Xavier J. Levine, and Tapio Schneider. "Local Energetic Constraints on Walker Circulation Strength." Journal of the Atmospheric Sciences 74, no. 6 (May 22, 2017): 1907–22. http://dx.doi.org/10.1175/jas-d-16-0219.1.
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Abstract The weakening of tropical overturning circulations is a robust response to global warming in climate models and observations. However, there remain open questions on the causes of this change and the extent to which this weakening affects individual circulation features such as the Walker circulation. The study presents idealized GCM simulations of a Walker circulation forced by prescribed ocean heat flux convergence in a slab ocean, where the longwave opacity of the atmosphere is varied to simulate a wide range of climates. The weakening of the Walker circulation with warming results from an increase in gross moist stability (GMS), a measure of the tropospheric moist static energy (MSE) stratification, which provides an effective static stability for tropical circulations. Baroclinic mode theory is used to determine changes in GMS in terms of the tropical-mean profiles of temperature and MSE. The GMS increases with warming, owing primarily to the rise in tropopause height, decreasing the sensitivity of the Walker circulation to zonally anomalous net energy input. In the absence of large changes in net energy input, this results in a rapid weakening of the Walker circulation with global warming.
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Endre Nagy, Tibor. "Human blood circulation model based on flow laws of intensity and continuity in relation to earth’s surface gravity." Journal of Lung, Pulmonary & Respiratory Research 10, no. 2 (June 8, 2023): 46–54. http://dx.doi.org/10.15406/jlprr.2023.10.00301.
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With the help of the physical laws of flow, it is possible to describe the entire human blood circulation. However, this requires precise knowledge of the individual parameters. Within this, the determination of the flow rate included in the law of continuity is essential. Together with the data of the heart and circulation examination procedures, in order to establish the average human blood circulation, an intermediate velocity value must be selected, which is located in the middle between the two extreme velocities of the blood circulation. Another important factor from the point of view of the structure and operation of the model is the value of the earth's surface gravity. By finding the average flow speed value and using ‘g’, a torus-shaped circulation can be created, which can actually reflect the circulation conditions. By further refining the model, the pulmonary and systemic circulations can be separated and a ‘folded figure eight’ model can be formed. This realistically reflects the different sizes, flow and pressure conditions of the two blood circulations, as well as the work of the left and right sides of the heart.
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Wu, Yutian, and Olivier Pauluis. "Examination of Isentropic Circulation Response to a Doubling of Carbon Dioxide Using Statistical Transformed Eulerian Mean*." Journal of the Atmospheric Sciences 70, no. 6 (May 29, 2013): 1649–67. http://dx.doi.org/10.1175/jas-d-12-0235.1.
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Abstract Responses of the atmospheric circulation to a doubling of CO2 are examined in a global climate model, focusing on the circulation on both dry and moist isentropes. The isentropic circulations are reconstructed using the statistical transformed Eulerian mean (STEM), which approximates the isentropic flow from the Eulerian-mean and second-order moments. This approach also makes it possible to decompose the changes in the circulation into changes in zonal mean and eddy statistics. It is found that, as a consequence of CO2 doubling, the dry isentropic circulation weakens across all latitudes. The weaker circulation in the tropics is a result of the reduction in mean meridional circulation while the reduction in eddy sensible heat flux largely contributes to the slowdown of the circulation in the midlatitudes. The heat transport on dry isentropes, however, increases in the tropics because of the increase in dry effective stratification whereas it decreases in the extratropics following the reduction in eddy sensible heat transport. Distinct features are found on moist isentropes. In the tropics, the circulation weakens, but without much change in heat transport. The extratropical circulation shifts poleward with an intensification (weakening) on the poleward (equatorward) flank, primarily because of the change in eddy latent heat transport. The total heat transport in the midlatitudes also shows a poleward shift but is of smaller magnitude. The differences between the dry and moist circulations reveal that in a warming world the increase in midlatitude eddy moisture transport is associated with an increase in warm moist air exported from the subtropics into the midlatitude storm tracks.
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French, Michael M., Howard B. Bluestein, David C. Dowell, Louis J. Wicker, Matthew R. Kramar, and Andrew L. Pazmany. "High-Resolution, Mobile Doppler Radar Observations of Cyclic Mesocyclogenesis in a Supercell." Monthly Weather Review 136, no. 12 (December 1, 2008): 4997–5016. http://dx.doi.org/10.1175/2008mwr2407.1.
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Abstract On 15 May 2003, two ground-based, mobile, Doppler radars scanned a supercell that moved through the Texas Panhandle and cyclically produced mesocyclones. The two radars collected data from the storm during a rapid cyclic mesocyclogenesis stage and a more slowly evolving tornadic period. A 3-cm-wavelength radar scanned the supercell continuously for a short time after it was cyclic but close to the time of tornadogenesis. A 5-cm-wavelength radar scanned the supercell the entire time it exhibited cyclic behavior and for an additional 30 min after that. The volumetric data obtained with the 5-cm-wavelength radar allowed for the individual circulations to be analyzed at multiple levels in the supercell. Most of the circulations that eventually dissipated moved rearward with respect to storm motion and were located at distances progressively farther away from the region of rear-flank outflow. The circulations associated with a tornado did not move nearly as far rearward relative to the storm. The mean circulation diameters were approximately 1–4 km and had lifetimes of 10–30 min. Circulation dissipation often, but not always, occurred following decreases in circulation diameter, while changes in maximum radial wind shear were not reliable indicators of circulation dissipation. In one instance, a pair of circulations rotated cyclonically around, and moved toward, each other; the two circulations then combined to form one circulation. Single-Doppler radial velocities from both radars were used to assess the differences between the pretornadic circulations and the tornadic circulations. Storm outflow in the rear flank of the storm increased notably during the time cyclic mesocyclogenesis slowed and tornado formation commenced. Large storm-relative inflow likely advected the pretornadic circulations rearward in the absence of organized outflow. The development of strong outflow in the rear flank probably balanced the strong inflow, allowing the tornadic circulations to stay in areas rich in vertical vorticity generation.
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Wang, Yafei, Jianzhao Qin, and Lijuan Zhu. "The Okhotsk-Japan Circulation Pattern and the Heavy Rainfall in Beijing in 2012 Summer." Advances in Meteorology 2015 (2015): 1–10. http://dx.doi.org/10.1155/2015/483970.
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Using station precipitation and reanalysis data, we examined the evolution of the large-scale circulations associated with the heavy rainfall event that occurred around July 21, 2012 (721 heavy rainfall). This study focuses on a role that the large-scale circulations named “the Okhotsk-Japan (OKJ) circulation pattern” played in causing the heavy rainfall case. We found that the 721 heavy rainfall occurred under a background of the OKJ circulation that persisted for about 10 days. However, the pattern was different from the normal OKJ circulation, for this circulation pattern accompanied a blocking high between the Ural Mountains and the Baikal Lake. This difference resulted from the seasonal change of the basic flow. The related Rossby wave propagated eastward during the persisting period of the dominated OKJ pattern. This caused the development of a low-pressure system around the Baikal Lake and the weakening of a ridge around the Okhotsk Sea. The slow evolution of the OKJ circulation created a favorable environment for the moisture transport to northern China, assisting in the generation of the 721 heavy rainfall.
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Jiang, Yunyan, Jinyuan Xin, Ying Wang, Guiqian Tang, Yuxin Zhao, Danjie Jia, Dandan Zhao, et al. "The thermodynamic structures of the planetary boundary layer dominated by synoptic circulations and the regular effect on air pollution in Beijing." Atmospheric Chemistry and Physics 21, no. 8 (April 23, 2021): 6111–28. http://dx.doi.org/10.5194/acp-21-6111-2021.
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Abstract. To investigate the impacts of multiscale circulations on the planetary boundary layer (PBL), we have carried out the PBL thermodynamic structure field experiment with a Doppler wind profile lidar, a microwave radiometer, and a ceilometer from January 2018 to December 2019 in Beijing. We found that the direct regulatory effect of synoptic circulation worked through transporting and accumulating pollutants in front of mountains in the daytime, while the indirect effect of multiscale circulations worked through coupling mechanisms in the nighttime. The horizontal coupling of different-direction winds produced a severe pollution convergent zone. The vertical coupling of upper environmental winds and lower regional breezes regulated the mixing and diffusion of pollutants by generating dynamic wind shear and advective temperature inversion. We also found that the dominating synoptic circulations led to great differences in PBL thermodynamic structure and pollution. The cyclonic circulation resulted in a typical multilayer PBL characterized by high vertical shear (600 m), temperature inversion (900 m), and an inhomogeneous stratification. Meanwhile, strong regional breezes pushed the pollution convergent zone to the south of Beijing. The southwesterly circulation resulted in a mono-layer PBL characterized by low vertical shear (400 m) and inversion (200 m). The westerly circulation led to a hybrid-structure PBL, and the advective inversion was generated by the vertical shear of zonal winds. Strong environmental winds of southwesterly and westerly circulations pushed the severe-pollution zone to the front of mountains. There was no distinct PBL structure under the anticyclone circulation. The study systematically revealed the appreciable effects of synoptic and regional circulations on PBL structure and air quality, which enriched the prediction theory of atmospheric pollution in the complex terrain.
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Pasquier, Benoît, Mark Holzer, Matthew A. Chamberlain, Richard J. Matear, Nathaniel L. Bindoff, and François W. Primeau. "Optimal parameters for the ocean's nutrient, carbon, and oxygen cycles compensate for circulation biases but replumb the biological pump." Biogeosciences 20, no. 14 (July 26, 2023): 2985–3009. http://dx.doi.org/10.5194/bg-20-2985-2023.
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Abstract. Accurate predictive modeling of the ocean's global carbon and oxygen cycles is challenging because of uncertainties in both biogeochemistry and ocean circulation. Advances over the last decade have made parameter optimization feasible, allowing models to better match observed biogeochemical fields. However, does fitting a biogeochemical model to observed tracers using a circulation with known biases robustly capture the inner workings of the biological pump? Here we embed a mechanistic model of the ocean's coupled nutrient, carbon, and oxygen cycles into two circulations for the current climate. To assess the effects of biases, one circulation (ACCESS-M) is derived from a climate model and the other from data assimilation of observations (OCIM2). We find that parameter optimization compensates for circulation biases at the expense of altering how the biological pump operates. Tracer observations constrain pump strength and regenerated inventories for both circulations, but ACCESS-M export production optimizes to twice that of OCIM2 to compensate for ACCESS-M having lower sequestration efficiencies driven by less efficient particle transfer and shorter residence times. Idealized simulations forcing complete Southern Ocean nutrient utilization show that the response of the optimized system is sensitive to the embedding circulation. In ACCESS-M, Southern Ocean nutrient and dissolved inorganic carbon (DIC) trapping is partially short circuited by unrealistically deep mixed layers. For both circulations, intense Southern Ocean production deoxygenates Southern-Ocean-sourced deep waters, muting the imprint of circulation biases on oxygen. Our findings highlight that the biological pump's plumbing needs careful assessment to predict the biogeochemical response to ecological changes, even when optimally matching observations.
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Fernández-Rodriguez, Conrado M., Ignacio R. Prada, Jesús Prieto, Luis M. Montuenga, Ted Elsasser, Jorge Quiroga, Mercedes Moreiras, Amalia Andrade, and Frank Cuttitta. "Circulating adrenomedullin in cirrhosis: relationship to hyperdynamic circulation." Journal of Hepatology 29, no. 2 (August 1998): 250–56. http://dx.doi.org/10.1016/s0168-8278(98)80010-x.
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Jiao, Fangyi, Dongchao Zhang, and Xiyue Zheng. "A study on the mechanisms of building a new development pattern through new urbanization from the perspective of industrial capital circulation." China Political Economy 7, no. 1 (November 22, 2024): 33–46. http://dx.doi.org/10.1108/cpe-06-2024-039.
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PurposeThis paper analyzes and discusses the fundamental role of new urbanization in the construction of a new development pattern based on the specific practice of China’s new urbanization construction, combining the classical Marxist ideas in urbanization and the theory of the industrial capital circulation, and proposes to remove blockages in the domestic and international circulations through developing new urbanization and construct a new development pattern with the domestic circulation as the mainstay and the domestic and international circulations promoting each other, thereby achieving high-quality national economic operation.Design/methodology/approachBased on the theory of industrial capital circulation, this paper elucidates the general process of domestic and international economic circulations, critically examines the bottlenecks and challenges in economic circulation, and emphasizes the mechanisms through which new urbanization contributes to the formation of a new development pattern.FindingsThe people-centered new urbanization can effectively release domestic demand, optimize investment supply, and stabilize market participants’ expectations, linking the national economic circulation from production to consumption and alleviating supply and demand mismatches, which has a fundamental role in building the new development pattern.Originality/valueWe should focus on creating a comprehensive domestic demand system based on counties while fostering a unified domestic market led by urban clusters and metropolitan areas to stabilize and enhance the expectations of both domestic and international market participants.
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Kuznetsova, Daria, Thibaut Dauhut, and Jean-Pierre Chaboureau. "The Three Atmospheric Circulations over the Indian Ocean and the Maritime Continent and Their Modulation by the Passage of the MJO." Journal of the Atmospheric Sciences 76, no. 2 (February 1, 2019): 517–31. http://dx.doi.org/10.1175/jas-d-18-0188.1.
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Abstract The passage of the Madden–Julian oscillation (MJO) over the Indian Ocean and the Maritime Continent is investigated during the episode of 23–30 November 2011. A Meso-NH convection-permitting simulation with a horizontal grid spacing of 4 km is examined. The simulation reproduces the MJO signal correctly, showing the eastward propagation of the primary rain activity. The atmospheric overturning is analyzed using the isentropic method, which separates the ascending air with high equivalent potential temperature from the subsiding air with low equivalent potential temperature. Three key circulations are found. The first two circulations are a tropospheric deep circulation spanning from the surface to an altitude of 14 km and an overshoot circulation within the tropical tropopause layer. As expected for circulations associated with deep convection, their intensities, as well as their diabatic tendencies, increase during the active phase of the MJO, while their entrainment rates decrease. The third circulation is characterized by a rising of air with low equivalent potential temperature in the lower free troposphere. The intensity of the circulation, as well as its depth, varies with the MJO activity. During the suppressed phase, this circulation is associated with a dry air intrusion from the subtropical region into the tropical band and shows a strong drying of the lower to middle troposphere.
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Kriest, Iris, Paul Kähler, Wolfgang Koeve, Karin Kvale, Volkmar Sauerland, and Andreas Oschlies. "One size fits all? Calibrating an ocean biogeochemistry model for different circulations." Biogeosciences 17, no. 12 (June 18, 2020): 3057–82. http://dx.doi.org/10.5194/bg-17-3057-2020.
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Abstract. Global biogeochemical ocean models are often tuned to match the observed distributions and fluxes of inorganic and organic quantities. This tuning is typically carried out “by hand”. However, this rather subjective approach might not yield the best fit to observations, is closely linked to the circulation employed and is thus influenced by its specific features and even its faults. We here investigate the effect of model tuning, via objective optimisation, of one biogeochemical model of intermediate complexity when simulated in five different offline circulations. For each circulation, three of six model parameters have been adjusted to characteristic features of the respective circulation. The values of these three parameters – namely, the oxygen utilisation of remineralisation, the particle flux parameter and potential nitrogen fixation rate – correlate significantly with deep mixing and ideal age of North Atlantic Deep Water (NADW) and the outcrop area of Antarctic Intermediate Waters (AAIW) and Subantarctic Mode Water (SAMW) in the Southern Ocean. The clear relationship between these parameters and circulation characteristics, which can be easily diagnosed from global models, can provide guidance when tuning global biogeochemistry within any new circulation model. The results from 20 global cross-validation experiments show that parameter sets optimised for a specific circulation can be transferred between similar circulations without losing too much of the model's fit to observed quantities. When compared to model intercomparisons of subjectively tuned, global coupled biogeochemistry–circulation models, each with different circulation and/or biogeochemistry, our results show a much lower range of oxygen inventory, oxygen minimum zone (OMZ) volume and global biogeochemical fluxes. Export production depends to a large extent on the circulation applied, while deep particle flux is mostly determined by the particle flux parameter. Oxygen inventory, OMZ volume, primary production and fixed-nitrogen turnover depend more or less equally on both factors, with OMZ volume showing the highest sensitivity, and residual variability. These results show a beneficial effect of optimisation, even when a biogeochemical model is first optimised in a relatively coarse circulation and then transferred to a different finer-resolution circulation model.
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Suzuki, Nobuhiro. "On the physical mechanisms of the two-way coupling between a surface wave field and a circulation consisting of a roll and streak." Journal of Fluid Mechanics 881 (October 25, 2019): 906–50. http://dx.doi.org/10.1017/jfm.2019.752.
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The governing equations of a surface wave field and a coexisting roll–streak circulation typical of Langmuir circulations or submesoscale frontal circulations are derived to better describe their two-way interactions. The gradients and vertical velocities of the roll–streak circulation induce wave refraction, amplitude modulation and higher-order waves. These changes then produce wave–wave nonlinear forces and divergence of the wave-induced mass transport, both of which in turn affect the circulation. To accurately represent these processes, both a wave theory and a wave-averaged theory are developed without relying on any extrapolation, any spatiotemporal mapping or an approximation that treats the wave-induced mass divergence as being concentrated at the surface. This wave theory finds seven types of current-induced higher-order wave motions. It also determines the wave dynamics such as the governing equation of the wave action density valid in the presence of the complex circulation. The evolution of the wave action density is clearly affected by the upwelling or downwelling. The new wave-averaged theory presents the governing equations of the wave-averaged circulation which satisfies the wave-averaged mass conservation. This circulation is different from the circulation considered to satisfy the mass conservation in the Craik–Leibovich theory, and the difference becomes critical when the wave field evolves due to refraction. In this case, compared to the Craik–Leibovich theory, long waves are more important and also the rolls are more weakly forced.
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Lian, Yuchen, Adam P. Showman, Xianyu Tan, and Yongyun Hu. "Influences of Internal Forcing on Atmospheric Circulations of Irradiated Giant Planets." Astrophysical Journal 928, no. 2 (April 1, 2022): 166. http://dx.doi.org/10.3847/1538-4357/ac5598.
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Abstract Close-in giant planets with strong stellar irradiation show atmospheric circulation patterns with strong equatorial jets and global-scale stationary waves. So far, almost all modeling works on atmospheric circulations of such giant planets have mainly considered external radiation alone, without taking into account the role of internal heat fluxes or just treating it in very simplified ways. Here, we study atmospheric circulations of strongly irradiated giant planets by considering the effect of internal forcing, which is characterized by small-scale stochastic interior thermal perturbations, using a three-dimensional atmospheric general circulation model. We show that the perturbation-excited waves can largely modify atmospheric circulation patterns in the presence of relatively strong internal forcing. Specifically, our simulations demonstrate three circulation regimes: a superrotation regime, a midlatitude-jet regime, and a quasi-periodic oscillation regime, depending on the relative importance of external and internal forcings. It is also found that strong internal forcing can cause noticeable modifications of the thermal phase curves.
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Nagao, Shigeto. "Structures and Interactions of Quantum Particles Based on the Energy Circulation Theory." Reports in Advances of Physical Sciences 03, no. 01 (March 2019): 1950001. http://dx.doi.org/10.1142/s2424942419500014.
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Although the quark model is widely accepted, it is unknown what the origin of the electric charge of a quark is and why the charge magnitudes are fractional and different among the [Formula: see text] and [Formula: see text] quarks. Here we propose a novel scheme for quantum particles independent of quantum chromodynamics and quarks. We previously reported the energy circulation theory, in which the fundamental force works between antiparallel energy movements based on momentums, and forms an energy circulation. The electric charge is the momentum in the hidden dimension of an energy circulation in hidden–space dimensions. In this paper, we examine the interactions between energy circulations precisely covering the whole range of distance, and derive formulas for strong and weak nuclear interactions. The strong force is an inter-circulation interaction by the fundamental force. The weak interaction is an orthogonal separation of an energy circulation in space–space dimensions to two halves. A quantum particle consists of one or plural energy circulations in a unit space of radius of the lowest-frequency hidden dimension. We propose the respective compositions of energy circulations for major particles so that they as much conform to reported decays, spin and rest-mass values. This new model of particles provides potential solutions to unexplained issues from the Standard Model as follows: The new model presents the theoretical origin of the electric charge and its elementary charge. Because elementary components of hadrons are energy circulations instead of quarks, it is not required to introduce a fractional electric charge. A composition of elementary energy circulations for a quantum particle shows its electric charge and mass (rest energy) by the addition of those of elements. Furthermore, the model successfully exhibits strong and weak nuclear interactions as well as the electric force.
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Yang, Xuanyuan, and Yifa Sheng. "Research on MMC Circulation Suppression Technology." Journal of Physics: Conference Series 2479, no. 1 (April 1, 2023): 012058. http://dx.doi.org/10.1088/1742-6596/2479/1/012058.
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Abstract Modular multilevel converters (MMCs) are extensively used in flexible high-voltage DC transmission systems. As an important part of them, it plays an important role in the normal use of MMCs. The main additional loss in the system is generated by the second harmonic in the circulating current. By summarizing and comparing current circulation control strategies. Based on the current research status of circulation suppression, we prospect the research direction of the MMC circulating current suppression.
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Nair, Anish Kumar M., K. V. Sambhu Namboodiri, Mahesh C., and Dileep P. K. "Cyclonic and anticyclonic circulations of 850 hPa over India and adjoining areas based on highly packed hand drawn streamline charts : part 1 - characteristics." MAUSAM 76, no. 2 (March 28, 2025): 553–68. https://doi.org/10.54302/mausam.v76i2.5906.
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Cyclonic (‘C’) and Anticyclonic (‘A’) circulations play a decisive role in deciding the weather of a region. Therefore, understanding the characteristics of circulation and their spatio-temporal distribution has become important. The present exploratory study characterizes circulations of 850 hPa pressure level over India and adjoining regions. Highly packed wind streamlines are drawn for 850 hPa integrating wind data from satellites, radiosondes, pilot balloons and Doppler Weather Radars. ‘C’ and ‘A’ circulations centre points are identified and the characteristics of their distribution are explored spatially on seasonal, long-term and monthly time scale over the Indian and surrounding regions for 2014 to 2020. Several meteorological significant features are visually manifested in ‘C’ and (‘A’) circulations and their role in dynamics is discussed in the manuscript. Frequency distribution shows wide-spread and large numbers of (‘C’) circulations are present over the north and northwest India, the Indo-Gangetic plain, and in the east equatorial Indian Ocean region. Seasonal analysis reveals an association with the southwest monsoon trough, the head Bay of Bengal lows, heat lows over land and in the southern peninsula. (‘A’) circulation centre point distribution is concentrated further south of the trough region and concentrated mainly on the land. The winter season has noticeably more (‘A’) circulation which could be attributed to the descending limb of the Hadley Cell. Spatial distribution of circulation shows land-sea contrast. The analysis has several applications, including operational weather forecasting, aviation and ballistic meteorology and scope for advanced research.
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Ji, Shengxian, Fei Xiao, Guisheng Jie, Shan Gao, and Jiamin Ye. "A Power Circulating Suppression Method for Parallel Transient Inverters with Instantaneous Phase Angle Compensation." Energies 17, no. 17 (September 1, 2024): 4368. http://dx.doi.org/10.3390/en17174368.
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A unidirectional link is typically incorporated into the DC input side of an inverter to ensure the reliability and stability of the microgrid power supply. Due to impedance and control variations among inverters, circulating currents may rapidly arise during the operation of parallel transient inverters. Nonetheless, the unidirectional power circulating in a DC unidirectional link results in energy accumulation on the DC side, causing DC bus voltage pumping and affecting MGs’ operation safety and stability. This paper proposes a non-communication-based circulation suppression strategy to suppress power circulation in parallel transients based on the local information of inverters. First, a parallel transient is modeled, and the power circulation phenomenon and its influencing factors are analyzed. Then, the instantaneous power and absorbed active energy are calculated to adjust the phase of the inverter output voltage and suppress power circulation. Moreover, the output frequency is adjusted to balance the DC-side voltage of each inverter. Then, the stability of the parallel system after adding the circulation suppression control strategy is verified using the Lyapunov function method. Finally, simulation and experimental results verify the effectiveness of the proposed power circulation suppression strategy.
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Suresh, Karthik, and Larissa A. Shimoda. "Lung Circulation." Comprehensive Physiology 6, no. 2 (April 2016): 897–943. https://doi.org/10.1002/j.2040-4603.2016.tb00688.x.
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ABSTRACTThe circulation of the lung is unique both in volume and function. For example, it is the only organ with two circulations: the pulmonary circulation, the main function of which is gas exchange, and the bronchial circulation, a systemic vascular supply that provides oxygenated blood to the walls of the conducting airways, pulmonary arteries and veins. The pulmonary circulation accommodates the entire cardiac output, maintaining high blood flow at low intravascular arterial pressure. As compared with the systemic circulation, pulmonary arteries have thinner walls with much less vascular smooth muscle and a relative lack of basal tone. Factors controlling pulmonary blood flow include vascular structure, gravity, mechanical effects of breathing, and the influence of neural and humoral factors. Pulmonary vascular tone is also altered by hypoxia, which causes pulmonary vasoconstriction. If the hypoxic stimulus persists for a prolonged period, contraction is accompanied by remodeling of the vasculature, resulting in pulmonary hypertension. In addition, genetic and environmental factors can also confer susceptibility to development of pulmonary hypertension. Under normal conditions, the endothelium forms a tight barrier, actively regulating interstitial fluid homeostasis. Infection and inflammation compromise normal barrier homeostasis, resulting in increased permeability and edema formation. This article focuses on reviewing the basics of the lung circulation (pulmonary and bronchial), normal development and transition at birth and vasoregulation. Mechanisms contributing to pathological conditions in the pulmonary circulation, in particular when barrier function is disrupted and during development of pulmonary hypertension, will also be discussed. © 2016 American Physiological Society. Compr Physiol 6:897‐943, 2016.
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Chung, Cheng-Ta, Chien-Hsun Wu, and Yi-Hsuan Hung. "Effects of Electric Circulation on the Energy Efficiency of the Power Split e-CVT Hybrid Systems." Energies 11, no. 9 (September 5, 2018): 2342. http://dx.doi.org/10.3390/en11092342.
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This paper aims at investigating the fundamental characteristics of energy efficiency for power split electronic-continuously-variable-transmission (e-CVT) hybrid systems under the operation of electric circulation, i.e., circulating part of the engine power through the generator and motor in form of electric energy to improve system efficiency as well as perform the continuously-variable-transmission (CVT) functionality. The relations of kinematics and energy conservation for each power component are constructed and analyzed to classify how the operating points of the engine in term of torque and rotational speed may vary under different degrees of electric circulation indicated by a parameter called ratio of circulating power. Thereby, power split e-CVT hybrid systems can be classified into three types: upward circulation, downward circulation, and neutral circulation. Accordingly, two power split e-CVT hybrid systems, one of input split type and the other of output split type, are selected to be analyzed regarding their operating characteristics and simulated on their performances of energy efficiency. As a result, the former is a type of downward circulation in favor of driving at low speed and high driving load, while the latter is a type of upward circulation with an advantage of driving at high speed and low driving load. Thereby, applying this analysis to investigate the effects of electric circulation on power split e-CVT systems may help the developers implement suitable energy management and control strategy in accordance with their corresponding operating characteristics of energy efficiency.
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Kang, Chuyan, Sijia Huo, Yingbo Yue, Haoyang Cui, Cheng Yang, Rongqiang Feng, Weibang Li, and Xin He. "Analysis of MMC Circulation Phase Sequence Separation and Research on Flexible Sliding Mode Circulation Suppression Method." Energies 18, no. 4 (February 17, 2025): 960. https://doi.org/10.3390/en18040960.
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Modular multilevel converter (MMC) circulating current suppression is an effective method in improving power conversion quality. However, due to the complex composition of circulation under a three-phase imbalanced state, as well as the limitations of existing sliding mode circulation suppression methods that can easily cause high-frequency oscillation in the system, the circulation suppression effectiveness still needs to be further improved. Firstly, this article clarifies the phase sequence law and key control factors of the circulation by separating the MMC circulation phase sequence and decoupling the model. Secondly, the generalized proportional integral sliding surface and the hyperbolic tangent convergence law are introduced into sliding mode control to improve the system’s ability to flexibly suppress the circulating current. Then, the proposed method is evaluated using the system power quality and insulated-gate bipolar transistor (IGBT) junction temperature amplitude. The results show that the proposed method reduces the total harmonic distortion of the bridge arm current to 1.28% and 1.03%, respectively, under three-phase balanced and imbalanced states, and effectively smooths the IGBT junction temperature fluctuation of submodules. It also improves the stability and robustness of MMC system to circulation suppression gain variations, sudden load changes, and switching failures. This article provides an effective method for the synchronous implementation of MMC circulation suppression and IGBT junction temperature smoothing under complex and variable operating conditions.
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Ferrari, Raffaele, Louis-Philippe Nadeau, David P. Marshall, Lesley C. Allison, and Helen L. Johnson. "A Model of the Ocean Overturning Circulation with Two Closed Basins and a Reentrant Channel." Journal of Physical Oceanography 47, no. 12 (December 2017): 2887–906. http://dx.doi.org/10.1175/jpo-d-16-0223.1.
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AbstractZonally averaged models of the ocean overturning circulation miss important zonal exchanges of waters between the Atlantic and Indo-Pacific Oceans. A two-layer, two-basin model that accounts for these exchanges is introduced and suggests that in the present-day climate the overturning circulation is best described as the combination of three circulations: an adiabatic overturning circulation in the Atlantic Ocean associated with transformation of intermediate to deep waters in the north, a diabatic overturning circulation in the Indo-Pacific Ocean associated with transformation of abyssal to deep waters by mixing, and an interbasin circulation that exchanges waters geostrophically between the two oceans through the Southern Ocean. These results are supported both by theoretical analysis of the two-layer, two-basin model and by numerical simulations of a three-dimensional ocean model.
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Yang, Xingtuan, Yanfei Sun, Zhiyong Liu, and Shengyao Jiang. "Natural Circulation Characteristics of a Symmetric Loop under Inclined Conditions." Science and Technology of Nuclear Installations 2014 (2014): 1–8. http://dx.doi.org/10.1155/2014/925760.
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Natural circulation is an important process for primary loops of some marine integrated reactors. The reactor works under inclined conditions when severe accidents happen to the ship. In this paper, to investigate the characteristics of natural circulation, experiments were conducted in a symmetric loop under the inclined angle of 0~45°. A CFD model was also set up to predict the behaviors of the loop beyond the experimental scope. Total circulation flow rate decreases with the increase of inclined angle. Meanwhile one circulation is depressed while the other is enhanced, and accordingly the disparity between the branch circulations arises and increases with the increase of inclined angle. Circulation only takes place in one branch circuit at large inclined angle. Also based on the CFD model, the influences of flow resistance distribution and loop configuration on natural circulation are predicted. The numerical results show that to design the loop with the configuration of big altitude difference and small width, it is favorable to reduce the influence of inclination; however too small loop width will cause severe reduction of circulation ability at large angle inclination.
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Kim, Dong Wan, and Sukyoung Lee. "The Role of Latent Heating Anomalies in Exciting the Summertime Eurasian Circulation Trend Pattern and High Surface Temperature." Journal of Climate 35, no. 2 (January 15, 2022): 801–14. http://dx.doi.org/10.1175/jcli-d-21-0392.1.
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Abstract Dynamical mechanisms for the summer Eurasian circulation trend pattern are investigated by analyzing reanalysis data and conducting numerical model simulations. The daily circulations that resemble the Eurasian circulation trend pattern are identified and categorized into two groups based on surface warming signal over central and eastern Europe. In the group with large warm anomaly, the upper-level circulation takes on a wave packet form over Eurasia, and there are enhanced latent heating anomalies centered over the North Sea and suppressed latent heating anomalies over the Caspian Sea. The numerical model calculations indicate that these latent heating anomalies can excite an upper-level circulation response that resembles the Eurasian circulation trend pattern. Additional analysis indicates that trends of these two latent heating centers contribute to the long-term circulation trend. In the weak warm anomaly group, the circulation pattern takes on a circumglobal teleconnection (CGT) pattern, and there is no heating signal that reinforces the circulation. These results indicate that not all CGT-like patterns excite temperature anomalies that are persistent and in phase with the trend pattern, and that quasi-stationary forcings, such as the latent heating anomalies, play an important role in driving the boreal summer circulation anomaly that accompanies the strong and persistent surface temperature signal.
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giusti, sandra. "closing remarks." Cardiology in the Young 14, S3 (October 2004): 97. http://dx.doi.org/10.1017/s1047951104006675.
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in the 17th century, william harvey discovered the circulation of the blood, describing at this time the pumping function of the heart and the “in series” disposition of the pulmonary and systemic circulations. these concepts provided the foundation for the development of modern cardiac physiology. during the three centuries that followed the discovery of circulation, many scientists studied and expanded our knowledge of cardiac and pulmonary function. with the description of complex congenital cardiac diseases, in particular functionally univentricular hearts, and with the development of their palliative surgical treatment, we have uncovered another type of cardiac physiology. in these cases, the circulation of the blood is characterized by an “in parallel” disposition of the pulmonary and systemic circulations, with direct venous–arterial connections in the absence of one pumping ventricle.
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Kelly, L., J. Kolbe, W. Mitzner, E. W. Spannhake, B. Bromberger-Barnea, and H. Menkes. "Bronchial blood flow affects recovery from constriction in dog lung periphery." Journal of Applied Physiology 60, no. 6 (June 1, 1986): 1954–59. http://dx.doi.org/10.1152/jappl.1986.60.6.1954.
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We investigated the effect of eliminating the bronchial circulation on recovery time from intravenous histamine challenge in canine lung periphery. Results from animals with intact bronchial circulations were compared with a second group in which the left lower lobe was isolated in situ. The pulmonary artery to this lobe was perfused and a bronchoscope was wedged in a small airway, which provided an index of resistance to airflow through the collateral system. The lobe was challenged with intravenous histamine, and the time constant of recovery (tau) from bronchoconstriction was measured. With or without pulmonary blood flow, elimination of the bronchial circulation increased tau 44.4 and 48.5%, respectively. This increase was similar to that found by stopping pulmonary blood flow alone (56.5%). Histamine challenges were also performed in sympathectomized or vagotomized animals with intact bronchial circulations. Neither of these conditions increased tau. We conclude that blood flow through the bronchial circulation affects the recovery time from intravenous histamine challenge in the lung periphery to a degree similar to that of the pulmonary circulation.
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Pottroff, Christy L. "Circulation." Early American Studies: An Interdisciplinary Journal 16, no. 4 (2018): 621–27. http://dx.doi.org/10.1353/eam.2018.0026.
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Hartroft, W. S. "Circulation." Annals of the New York Academy of Sciences 111, no. 1 (December 15, 2006): 534–37. http://dx.doi.org/10.1111/j.1749-6632.1963.tb36993.x.
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Agathocleous, Tanya, and Jason R. Rudy. "Circulation." Victorian Literature and Culture 46, no. 3-4 (2018): 621–25. http://dx.doi.org/10.1017/s1060150318000402.
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Wear, Andrew. "Circulation." Lancet 364, no. 9437 (September 2004): 835. http://dx.doi.org/10.1016/s0140-6736(04)16962-6.
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Kountchev, Jordan. "Circulation." Lancet 364, no. 9448 (November 2004): 1856. http://dx.doi.org/10.1016/s0140-6736(04)17437-0.
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Galcerà-Tomás, J., J. A. Nuño ade la Rosa, P. Rodriguez, G. Seller, G. Torres, M. Brù, T. Garcia-Paredes, et al. "Circulation." Intensive Care Medicine 18, S2 (October 1992): S115—S116. http://dx.doi.org/10.1007/bf03216350.
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Sealy, Jon. "Circulation." Appalachian Heritage 46, no. 2 (2018): 88–102. http://dx.doi.org/10.1353/aph.2018.0008.
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Lee, Thomas N., and Leonard J. Pietrafesa. "Circulation." Progress in Oceanography 19, no. 3-4 (January 1987): 267–312. http://dx.doi.org/10.1016/0079-6611(87)90011-5.
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Eff, Carine, and Isabelle Saint-Saëns. "liberté de circulation vs circulation libérale." Vacarme 41, no. 4 (2007): 84. http://dx.doi.org/10.3917/vaca.041.0084.
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Ronco, Claudio, and Rinaldo Bellomo. "Central Circulation, Peripheral Circulation and Recirculation." Blood Purification 15, no. 4-6 (1997): 334–45. http://dx.doi.org/10.1159/000170352.
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