Based on the annual frequency data of tropical cyclones from 1960 to 2005 and by the polynomial fit and statistical analysis, this work has discovered that TC activity in the 46a exhibits significant decadal-scale var...Based on the annual frequency data of tropical cyclones from 1960 to 2005 and by the polynomial fit and statistical analysis, this work has discovered that TC activity in the 46a exhibits significant decadal-scale variability. It has two high frequency periods (HFP) and two low frequency periods (LFP). Significant differences in the number of TCs between HFP and LFP are found in active TC seasons from July to October. Differences of large-scale circulation during HFP and LFP have been investigated with NCEP/NOAA data for the season. In HFP, the condition includes not only higher sea surface temperature, lower sea level pressure, larger divergence of upper air, larger relative vorticity at low levels and smaller vertical shear, but also 500-hPa wind vector being more available for TC activity and moving to western North Pacific, the position of the subtropical anticyclone over the western Pacific shifting more northward, and South Asian Anticyclone at 100-hPa being much smaller than that in LFP. The precipitation of western North Pacific has no clear influence on TC activity.展开更多
Objective:To investigate the clinical effects of applying the magnetic resonance double mismatch technique to endovascular treatment of acute anterior circulation,large vessel occlusion with cerebral infarction in an ...Objective:To investigate the clinical effects of applying the magnetic resonance double mismatch technique to endovascular treatment of acute anterior circulation,large vessel occlusion with cerebral infarction in an unknown time window.Methods:The research work was carried out in our hospital,the work was carried out from November 2018 to November 2019,the patients with acute anterior circulation large vessel occlusion with cerebral infarction who were treated in our hospital during this period,100 patients,50 patients with an unknown time window and 50 patients with definite time window were selected,and they were named as the experimental and control groups,given different examination methods,were given to investigate the clinical treatment effect.Results:Patients’data on HIHSS score before treatment,the incidence of intracranial hemorrhage and rate of Mrs≤2 rating after 90 days of treatment were not significantly different(P>0.05),which was not meaningful.The differences in data between the two groups concerning HIHSS scores were relatively significant before,and after treatment(P<0.05).Conclusion:The magnetic resonance double mismatch technique will be applied in the endovascular treatment of acute anterior circulation large vessel occlusion with cerebral infarction of unknown time window.展开更多
When large-scale circulating fluidized bed(CFB)boilers are working under a 1ow load condition.severe bed pressure swing often occurs and poses a serious threat to boiler stability and safety.Up to now,there are not en...When large-scale circulating fluidized bed(CFB)boilers are working under a 1ow load condition.severe bed pressure swing often occurs and poses a serious threat to boiler stability and safety.Up to now,there are not enough theoretical studies on the bed pressure swing phenomenon.展开更多
A comprehensive understanding of the hydrological cycle is essential for Earth system science and climate change research.The Water Cycle Intensity(WCI)is defined as the sum of precipitation and actual evapotranspirat...A comprehensive understanding of the hydrological cycle is essential for Earth system science and climate change research.The Water Cycle Intensity(WCI)is defined as the sum of precipitation and actual evapotranspiration within a landscape unit.It is a widely used metric to quantify the impact of climate change on the global distribution of water resources.The WCI in the Pamir Plateau,located at the heart of Asian Water Towers,has received little attention.Understanding this aspect is crucial for assessing the impact of climate change on the hydrological cycle and devising strategies to adapt to these changes.Our study assessed the spatiotemporal variation in WCI on the Pamir Plateau from 1980 to 2019 using the WCI framework.Additionally,we explored the teleconnection mechanisms linking the WCI with the Indian Ocean Dipole Mode Index(DMI),canonical El Niño-Southern Oscillation(ENSO),and El Niño Modoki(EMI)using the wavelet analysis method.The findings showed that the WCI of the Pamir Plateau experienced a statistically insignificant increase from 1980 to 2019,particularly after 2003.Spatially,the eastern Pamir Plateau WCI increased significantly,whereas the western region showed a non-significant downward trend.This study found that the WCI in the Pamir Plateau is significantly influenced by atmospheric circulation patterns,and the variation in the WCI in the Pamir Plateau is mainly affected by the canonical ENSO,as well as by the coupling effect of canonical ENSO,and EMI.In addition,based on the characteristics of the regional hydrological cycle,we developed water resource management policies targeting flood risks in the northern Pamir Plateau and drought trends in the southwestern region.These insights not only deepen our understanding of changes in terrestrial hydrological cycles and their underlying mechanisms under climate change but also provide important references for water resource management in the mountainous regions of Central Asia.展开更多
This study analyzed the heaviest snowfalls or icy-rainfalls occurring in southern China from January to the beginning of February 2008.The results are summarized as follows：the disaster was induced by the persistent ...This study analyzed the heaviest snowfalls or icy-rainfalls occurring in southern China from January to the beginning of February 2008.The results are summarized as follows：the disaster was induced by the persistent front of warm/cold air masses in southern China,which displayed an interaction between the weather systems in higher and lower latitudes.There was an adjustment for circulation at hemisphere scale during mid January by a variation of sign of the Arctic Oscillation（AO）index from negative to positive.The long lasting precipitation well coincided with a blocking situation centered near 80°E from mid January to the beginning of February.A diagnostic analysis indicates that stationary waves with an energy dispersion accompanying the blocking high propagated from upstream region in high latitudes to the south of the Yangtze River,which formed a maintaining energy source for the cyclonic circulation in situ.This resulted in that the large mass of cold air in high latitudes could not easily invade into the south but slowly shifted southward.On the other hand,the sea surface temperature（SST）over the warm pool of the western Pacific increased with a new history record due to the effect of the strong La Nina episode,which also blocked the cold air mass from the north.The blocking high collapsed around 30 January and the energy source for the local cyclonic circulation was cut off.Thus,the precipitation in southern China ceased after 1 February.展开更多
Background Despite successful reperfusion after thrombectomy for large vessel occlusion(LVO)stroke,up to half of patients are dependent or dead at 3-month follow-up.The aim of the current study is to demonstrate safet...Background Despite successful reperfusion after thrombectomy for large vessel occlusion(LVO)stroke,up to half of patients are dependent or dead at 3-month follow-up.The aim of the current study is to demonstrate safety and efficacy of administering adjunct intra-arterial(IA)tenecteplase in anterior circulation LVO patients who have achieved successful reperfusion defined as eTICI 2b50 to 3.Methods ANGEL-TNK is a multicentre,open-label,assessor-blinded endpoint,prospective randomised,controlled trial that will enrol up to 256 patients.Patients who meet inclusion criteria with anterior circulation LVO stroke and successful reperfusion will be randomised to receive IA tenecteplase or best medical management at 1:1 ratio.Results The primary endpoint is a 90-day excellent outcome defined as modified Rankin Scale(mRS)0–1.The primary safety endpoint is symptomatic intracranial haemorrhage within 48 hours from randomisation.Secondary endpoints include 90-day ordinal mRS,mRS 0–2,mRS 0–3,all-cause mortality and any intracranial haemorrhage.Conclusion In patients with anterior circulation LVO stroke,the ANGEL-TNK trial will inform whether adjunct IA tenecteplase administered after successful thrombectomy reperfusion improves patient outcomes.Trial registration number NCT05624190.展开更多
A fourth-order finite difference method is proposed and studied for the primitive equations(PEs)of large-scale atmospheric and oceanic flow based on mean vorticity formulation.Since the vertical average of the horizon...A fourth-order finite difference method is proposed and studied for the primitive equations(PEs)of large-scale atmospheric and oceanic flow based on mean vorticity formulation.Since the vertical average of the horizontal velocity field is divergence-free,we can introduce mean vorticity and mean stream function which are connected by a 2-D Poisson equation.As a result,the PEs can be reformulated such that the prognostic equation for the horizontal velocity is replaced by evolutionary equations for the mean vorticity field and the vertical derivative of the horizontal velocity.The mean vorticity equation is approximated by a compact difference scheme due to the difficulty of the mean vorticity boundary condition,while fourth-order long-stencil approximations are utilized to deal with transport type equations for computational convenience.The numerical values for the total velocity field(both horizontal and vertical)are statically determined by a discrete realization of a differential equation at each fixed horizontal point.The method is highly efficient and is capable of producing highly resolved solutions at a reasonable computational cost.The full fourth-order accuracy is checked by an example of the reformulated PEs with force terms.Additionally,numerical results of a large-scale oceanic circulation are presented.展开更多
基金National Key Fundamental Research and Development Plan of China (2004CB418303)Natural Science Foundation of China (40425009 40233028)
文摘Based on the annual frequency data of tropical cyclones from 1960 to 2005 and by the polynomial fit and statistical analysis, this work has discovered that TC activity in the 46a exhibits significant decadal-scale variability. It has two high frequency periods (HFP) and two low frequency periods (LFP). Significant differences in the number of TCs between HFP and LFP are found in active TC seasons from July to October. Differences of large-scale circulation during HFP and LFP have been investigated with NCEP/NOAA data for the season. In HFP, the condition includes not only higher sea surface temperature, lower sea level pressure, larger divergence of upper air, larger relative vorticity at low levels and smaller vertical shear, but also 500-hPa wind vector being more available for TC activity and moving to western North Pacific, the position of the subtropical anticyclone over the western Pacific shifting more northward, and South Asian Anticyclone at 100-hPa being much smaller than that in LFP. The precipitation of western North Pacific has no clear influence on TC activity.
文摘Objective:To investigate the clinical effects of applying the magnetic resonance double mismatch technique to endovascular treatment of acute anterior circulation,large vessel occlusion with cerebral infarction in an unknown time window.Methods:The research work was carried out in our hospital,the work was carried out from November 2018 to November 2019,the patients with acute anterior circulation large vessel occlusion with cerebral infarction who were treated in our hospital during this period,100 patients,50 patients with an unknown time window and 50 patients with definite time window were selected,and they were named as the experimental and control groups,given different examination methods,were given to investigate the clinical treatment effect.Results:Patients’data on HIHSS score before treatment,the incidence of intracranial hemorrhage and rate of Mrs≤2 rating after 90 days of treatment were not significantly different(P>0.05),which was not meaningful.The differences in data between the two groups concerning HIHSS scores were relatively significant before,and after treatment(P<0.05).Conclusion:The magnetic resonance double mismatch technique will be applied in the endovascular treatment of acute anterior circulation large vessel occlusion with cerebral infarction of unknown time window.
文摘When large-scale circulating fluidized bed(CFB)boilers are working under a 1ow load condition.severe bed pressure swing often occurs and poses a serious threat to boiler stability and safety.Up to now,there are not enough theoretical studies on the bed pressure swing phenomenon.
基金funded by the National Key R&D Program of China(No.2023YFE0103700).
文摘A comprehensive understanding of the hydrological cycle is essential for Earth system science and climate change research.The Water Cycle Intensity(WCI)is defined as the sum of precipitation and actual evapotranspiration within a landscape unit.It is a widely used metric to quantify the impact of climate change on the global distribution of water resources.The WCI in the Pamir Plateau,located at the heart of Asian Water Towers,has received little attention.Understanding this aspect is crucial for assessing the impact of climate change on the hydrological cycle and devising strategies to adapt to these changes.Our study assessed the spatiotemporal variation in WCI on the Pamir Plateau from 1980 to 2019 using the WCI framework.Additionally,we explored the teleconnection mechanisms linking the WCI with the Indian Ocean Dipole Mode Index(DMI),canonical El Niño-Southern Oscillation(ENSO),and El Niño Modoki(EMI)using the wavelet analysis method.The findings showed that the WCI of the Pamir Plateau experienced a statistically insignificant increase from 1980 to 2019,particularly after 2003.Spatially,the eastern Pamir Plateau WCI increased significantly,whereas the western region showed a non-significant downward trend.This study found that the WCI in the Pamir Plateau is significantly influenced by atmospheric circulation patterns,and the variation in the WCI in the Pamir Plateau is mainly affected by the canonical ENSO,as well as by the coupling effect of canonical ENSO,and EMI.In addition,based on the characteristics of the regional hydrological cycle,we developed water resource management policies targeting flood risks in the northern Pamir Plateau and drought trends in the southwestern region.These insights not only deepen our understanding of changes in terrestrial hydrological cycles and their underlying mechanisms under climate change but also provide important references for water resource management in the mountainous regions of Central Asia.
基金the National Natural Science Foundation of China under Grant No.40675034China-Japan intergovernmental cooperation program of the Japan International Cooperation Agency under 2009LASWZF04the program of Ministry of Science and Technology of China under 2009DFB20540
文摘This study analyzed the heaviest snowfalls or icy-rainfalls occurring in southern China from January to the beginning of February 2008.The results are summarized as follows：the disaster was induced by the persistent front of warm/cold air masses in southern China,which displayed an interaction between the weather systems in higher and lower latitudes.There was an adjustment for circulation at hemisphere scale during mid January by a variation of sign of the Arctic Oscillation（AO）index from negative to positive.The long lasting precipitation well coincided with a blocking situation centered near 80°E from mid January to the beginning of February.A diagnostic analysis indicates that stationary waves with an energy dispersion accompanying the blocking high propagated from upstream region in high latitudes to the south of the Yangtze River,which formed a maintaining energy source for the cyclonic circulation in situ.This resulted in that the large mass of cold air in high latitudes could not easily invade into the south but slowly shifted southward.On the other hand,the sea surface temperature（SST）over the warm pool of the western Pacific increased with a new history record due to the effect of the strong La Nina episode,which also blocked the cold air mass from the north.The blocking high collapsed around 30 January and the energy source for the local cyclonic circulation was cut off.Thus,the precipitation in southern China ceased after 1 February.
文摘Background Despite successful reperfusion after thrombectomy for large vessel occlusion(LVO)stroke,up to half of patients are dependent or dead at 3-month follow-up.The aim of the current study is to demonstrate safety and efficacy of administering adjunct intra-arterial(IA)tenecteplase in anterior circulation LVO patients who have achieved successful reperfusion defined as eTICI 2b50 to 3.Methods ANGEL-TNK is a multicentre,open-label,assessor-blinded endpoint,prospective randomised,controlled trial that will enrol up to 256 patients.Patients who meet inclusion criteria with anterior circulation LVO stroke and successful reperfusion will be randomised to receive IA tenecteplase or best medical management at 1:1 ratio.Results The primary endpoint is a 90-day excellent outcome defined as modified Rankin Scale(mRS)0–1.The primary safety endpoint is symptomatic intracranial haemorrhage within 48 hours from randomisation.Secondary endpoints include 90-day ordinal mRS,mRS 0–2,mRS 0–3,all-cause mortality and any intracranial haemorrhage.Conclusion In patients with anterior circulation LVO stroke,the ANGEL-TNK trial will inform whether adjunct IA tenecteplase administered after successful thrombectomy reperfusion improves patient outcomes.Trial registration number NCT05624190.
文摘A fourth-order finite difference method is proposed and studied for the primitive equations(PEs)of large-scale atmospheric and oceanic flow based on mean vorticity formulation.Since the vertical average of the horizontal velocity field is divergence-free,we can introduce mean vorticity and mean stream function which are connected by a 2-D Poisson equation.As a result,the PEs can be reformulated such that the prognostic equation for the horizontal velocity is replaced by evolutionary equations for the mean vorticity field and the vertical derivative of the horizontal velocity.The mean vorticity equation is approximated by a compact difference scheme due to the difficulty of the mean vorticity boundary condition,while fourth-order long-stencil approximations are utilized to deal with transport type equations for computational convenience.The numerical values for the total velocity field(both horizontal and vertical)are statically determined by a discrete realization of a differential equation at each fixed horizontal point.The method is highly efficient and is capable of producing highly resolved solutions at a reasonable computational cost.The full fourth-order accuracy is checked by an example of the reformulated PEs with force terms.Additionally,numerical results of a large-scale oceanic circulation are presented.
