Let {Xi,πki,ω} be an inverse sequence and X -- lim{Xi,πki,ω）. If each Xi is hereditarily （resp. metaLindelSf, σ-metaLindelSf, σ-orthocompact, weakly suborthocompact, δθ-refinable, weakly θ-refinable, weakly...Let {Xi,πki,ω} be an inverse sequence and X -- lim{Xi,πki,ω）. If each Xi is hereditarily （resp. metaLindelSf, σ-metaLindelSf, σ-orthocompact, weakly suborthocompact, δθ-refinable, weakly θ-refinable, weakly δθ-refinable）, then so is X.展开更多
The implication of the revelation of the inverse leaf aging sequence（ILAS） of wheat needs to be probed in theory and practice.Since 2005,the comparison experiment of the ILAS and the conventional leaf aging sequence...The implication of the revelation of the inverse leaf aging sequence（ILAS） of wheat needs to be probed in theory and practice.Since 2005,the comparison experiment of the ILAS and the conventional leaf aging sequence（CLAS） has been carried out to measure the canopy temperature and some important biological parameters of wheat.In nature,there existed the phenomenon that the wheat leaves aged in an sequence opposite to the conventional sequence and some of the leaves of ILAS wheat aged sequentially differed from those of CLAS wheat,i.e.,the penultimate leaves rather than the flag leaves aged last among the leaves at different leaf positions;in correspondence with the inverse leaf aging sequence,there appeared an unconventional leaf color structure at the late fruiting stage,which had yellow upper leaves and green lower leaves,opposite to the conventional leaf color structure that had green upper leaves and yellow lower leaves;the chlorophyll concentrations,soluble protein concentrations,transpiration rates,and net photosynthetic rates of the penultimate leaves of ILAS wheat unconventionally surpassed those of their flag leaves as their growth moved forward from one stage to another stage,and the ILAS wheat characteristically presented cold canopy temperature,i.e.,a cold tail canopy temperature at the late fruiting stage,or a cold canopy temperature at the whole fruiting stage;because ILAS wheat was unique in physiological process,its kernel weights were obviously higher than those of CLAS wheat,which closely related to the ＂relay＂ kernel-filling mode,which was different from the kernel-filling mode of CLAS wheat under which the flag leaves act as the main nutrient supply source at the whole fruiting stage.This study provided a new idea and approach for the theoretical exploration on wheat fruiting and aging,wheat yield further improvement,and cold type wheat and cold tail wheat breeding.展开更多
Assume that a convergent matrix sequence{A<sub>n</sub>}:A<sub>n</sub>→A（n→∞）, A<sub>n</sub>,A∈C<sup>3×3</sup>.We want to form a new matrix sequence {H<sub&...Assume that a convergent matrix sequence{A<sub>n</sub>}:A<sub>n</sub>→A（n→∞）, A<sub>n</sub>,A∈C<sup>3×3</sup>.We want to form a new matrix sequence {H<sub>n</sub>}, derived from {A<sub>n</sub>}, which has also A aslimit and whose convergence is faster than the of {A<sub>n</sub>}. Three rational extrapolation meth-ods for accelerating the convergence of matrix sequences {A<sub>n</sub>} are presented in this paper.The underlying methods are based on the generalized inverse for matrices which is展开更多
Background and purpose The low-field MRI is a promising tool to accurately diagnose strokes.We here report our study on the accuracy of a 0.23-Tesla(0.23-T)MRI using the haematoma enhanced inversion recovery(HEIR)sequ...Background and purpose The low-field MRI is a promising tool to accurately diagnose strokes.We here report our study on the accuracy of a 0.23-Tesla(0.23-T)MRI using the haematoma enhanced inversion recovery(HEIR)sequence to detect acute ischaemic stroke(AIS)and intracerebral haemorrhage(ICH)within 24 hours of symptom onset.Methods A novel HEIR sequence based on fluid-attenuated inversion recovery T1-weighted,with a scanning time of 1 min and 17 s,was developed using an ICH and AIS pig model on a 0.23-T MRI.Images of the pig model were obtained hourly for 24 hours in order to monitor value changes on T1/T2 and verify the differential diagnosis of AIS and ICH.Then,30 patients with AIS and 30 patients with ICH with confirmed diagnoses by 3T-MRI/CT were included.Diagnostic criteria on a 0.23-T MRI for ICH was the hyperintensity signal on both the diffusion-weighted imaging(DWI)and HEIR sequence,while for AIS was the hyperintensity on DWI and isointensity on the HEIR sequence.Two blinded raters independently assessed the images obtained by the 0.23-T MRI for the presence of ICH/AIS.Results In the pig model,setting the inversion time to 800 ms enabled clear differentiation of ICH from brain parenchymal tissue and AIS.In real patients,a correct 0.23-T MRI diagnosis of either an AIS or ICH was made in all 60 patients within 24 hours of symptom onset(100%overall accuracy).No adverse events occurred.Conclusions The 0.23-T MRI may have the potential to differentiate cerebral haemorrhage from cerebral infarction with both speed and accuracy,making brain MRI scans easier,faster and cheaper.It might be possible to improve the screening imaging process for strokes in the emergency room.Further multicentre studies are needed to validate our findings.展开更多
文摘Let {Xi,πki,ω} be an inverse sequence and X -- lim{Xi,πki,ω）. If each Xi is hereditarily （resp. metaLindelSf, σ-metaLindelSf, σ-orthocompact, weakly suborthocompact, δθ-refinable, weakly θ-refinable, weakly δθ-refinable）, then so is X.
基金supported by the National Natural Science Foundation of China (30270766,30470333)
文摘The implication of the revelation of the inverse leaf aging sequence（ILAS） of wheat needs to be probed in theory and practice.Since 2005,the comparison experiment of the ILAS and the conventional leaf aging sequence（CLAS） has been carried out to measure the canopy temperature and some important biological parameters of wheat.In nature,there existed the phenomenon that the wheat leaves aged in an sequence opposite to the conventional sequence and some of the leaves of ILAS wheat aged sequentially differed from those of CLAS wheat,i.e.,the penultimate leaves rather than the flag leaves aged last among the leaves at different leaf positions;in correspondence with the inverse leaf aging sequence,there appeared an unconventional leaf color structure at the late fruiting stage,which had yellow upper leaves and green lower leaves,opposite to the conventional leaf color structure that had green upper leaves and yellow lower leaves;the chlorophyll concentrations,soluble protein concentrations,transpiration rates,and net photosynthetic rates of the penultimate leaves of ILAS wheat unconventionally surpassed those of their flag leaves as their growth moved forward from one stage to another stage,and the ILAS wheat characteristically presented cold canopy temperature,i.e.,a cold tail canopy temperature at the late fruiting stage,or a cold canopy temperature at the whole fruiting stage;because ILAS wheat was unique in physiological process,its kernel weights were obviously higher than those of CLAS wheat,which closely related to the ＂relay＂ kernel-filling mode,which was different from the kernel-filling mode of CLAS wheat under which the flag leaves act as the main nutrient supply source at the whole fruiting stage.This study provided a new idea and approach for the theoretical exploration on wheat fruiting and aging,wheat yield further improvement,and cold type wheat and cold tail wheat breeding.
基金The works is supported by the National Natural Science Foundation of China(19871054)
文摘Assume that a convergent matrix sequence{A<sub>n</sub>}:A<sub>n</sub>→A（n→∞）, A<sub>n</sub>,A∈C<sup>3×3</sup>.We want to form a new matrix sequence {H<sub>n</sub>}, derived from {A<sub>n</sub>}, which has also A aslimit and whose convergence is faster than the of {A<sub>n</sub>}. Three rational extrapolation meth-ods for accelerating the convergence of matrix sequences {A<sub>n</sub>} are presented in this paper.The underlying methods are based on the generalized inverse for matrices which is
基金National Natural Science Foundation of China(grant no.82271329grant no.82471356).
文摘Background and purpose The low-field MRI is a promising tool to accurately diagnose strokes.We here report our study on the accuracy of a 0.23-Tesla(0.23-T)MRI using the haematoma enhanced inversion recovery(HEIR)sequence to detect acute ischaemic stroke(AIS)and intracerebral haemorrhage(ICH)within 24 hours of symptom onset.Methods A novel HEIR sequence based on fluid-attenuated inversion recovery T1-weighted,with a scanning time of 1 min and 17 s,was developed using an ICH and AIS pig model on a 0.23-T MRI.Images of the pig model were obtained hourly for 24 hours in order to monitor value changes on T1/T2 and verify the differential diagnosis of AIS and ICH.Then,30 patients with AIS and 30 patients with ICH with confirmed diagnoses by 3T-MRI/CT were included.Diagnostic criteria on a 0.23-T MRI for ICH was the hyperintensity signal on both the diffusion-weighted imaging(DWI)and HEIR sequence,while for AIS was the hyperintensity on DWI and isointensity on the HEIR sequence.Two blinded raters independently assessed the images obtained by the 0.23-T MRI for the presence of ICH/AIS.Results In the pig model,setting the inversion time to 800 ms enabled clear differentiation of ICH from brain parenchymal tissue and AIS.In real patients,a correct 0.23-T MRI diagnosis of either an AIS or ICH was made in all 60 patients within 24 hours of symptom onset(100%overall accuracy).No adverse events occurred.Conclusions The 0.23-T MRI may have the potential to differentiate cerebral haemorrhage from cerebral infarction with both speed and accuracy,making brain MRI scans easier,faster and cheaper.It might be possible to improve the screening imaging process for strokes in the emergency room.Further multicentre studies are needed to validate our findings.
