This study was conducted on the spatial distribution characteristics of surface tidal currents in the southwestern Taiwan Strait based on the quasi-harmonic analysis of current data obtained by two high frequency surf...This study was conducted on the spatial distribution characteristics of surface tidal currents in the southwestern Taiwan Strait based on the quasi-harmonic analysis of current data obtained by two high frequency surface wave radar(HFSWR) systems. The analysis shows that the tidal current pattern in the southwestern Taiwan Strait is primarily semi-diurnal and influenced significantly by shallow water constituents. The spatial distribution of tidal current ellipses of M2 is probably affected by the interaction between two different systems of tide wave, one from the northern mouth of Taiwan Strait and the other from the Bashi Channel. The directions of the major axes of M2 tidal current ellipses coincide roughly with the axis of the Taiwan Strait. The spatial distribution of the magnitudes of the probable maximum current velocity(PMCS) shows gradual increase of the velocity from northeast to southwest, which is in accordance with the spatial distribution of the measured maximum current velocity(MMCS). The directions of the residual currents are in accordance with the direction of the prevailing monsoon wind at the Taiwan Strait and the direction of the Taiwan warm current during summer. The bathymetry also shows a significant effect on the spatial distribution characteristics of tidal currents.展开更多
By the aftershock frequency estimation method based on the calculation of coseismic static Coulomb stress changes and rate-and state-dependent fault constitutive law,we calculate the frequency of "direct "af...By the aftershock frequency estimation method based on the calculation of coseismic static Coulomb stress changes and rate-and state-dependent fault constitutive law,we calculate the frequency of "direct "aftershocks of the Wenchuan earthquake related to coseismic static Coulomb stress changes in its aftershock zone and the areas nearby.It shows that the frequency is significantly lower than the truth in the main rupture zone,especially in the southern rupture zone,due to the decrease of stress level on the rupture plane of the main shock resulting from coseismic Coulomb stress change.The study also shows that the effect of the Coulomb stress change on the duration of aftershock activity is associated with the lower limit magnitude.The duration is about 15-16 months for aftershocks above ML4.0,and close to 60 months for aftershocks above ML3.5.In this period,the ratio of the"direct"aftershocks caused by coseismic Coulomb stress change ranges between 44.7% to48.6%,which suggests that,even in the "effective"period of coseismic Coulomb stress changes,about half of the aftershocks on the main shock rupture plane are independent of coseismic Coulomb stress changes.It is pointed out that those aftershocks may be related to the afterslip or the viscoelastic relaxation,which are time dependent cases.展开更多
Background SCN1A is the most well-recognized and commonly mutated gene related to epilepsy.This study analyzed the characteristic spatial and frequency distributions of SCN1A mutations,aiming to provide important insi...Background SCN1A is the most well-recognized and commonly mutated gene related to epilepsy.This study analyzed the characteristic spatial and frequency distributions of SCN1A mutations,aiming to provide important insight into the mutagenesis etiopathology of SCN1A-associated epilepsy.Methods Epilepsy-associated SCN1A variants were retrieved from the SCN1A mutation database,the HGMD database,and literature reviews.The base substitutions,mutation frequencies in CpG dinucleotides,and spatial distributions of mutations in terms of exons and structural domains were analyzed.Results A total of 2621 SCN1A variants were identifed in 5106 unrelated cases.The most common type was missense mutation,followed by frameshift mutations and splice site mutations.Among the missense mutations,transitions within CpG dinucleotides were much more recurrently identifed than transitions within non-CpG dinucleotides,and the most common type was the G>A transition.Among the nonsense mutations,the most predominant type of single-base substitution was the C>T transition,among which 75.3%(235/312)were within CpG sites.The most common“hotspot”codons for missense mutations were codons 101,946,and 1783;while for nonsense mutations it was codon 712.One-base deletion or insertion was the most common type of frameshift mutation,causing protein truncation.The three most common frameshift mutations were c.5536_5539delAAAC,c.4554dupA,and c.5010_5013delGTTT.Splice mutations were the most frequently identifed in exon 4 with a hotspot site c.602+1G>A.The spatial distribution of missense mutations showed that exons 22 and 4 had the highest mutation density(111 and 84 mutations per 100 bp,respectively),and exon 12 had the lowest mutation density,with 4 mutations per 100 bp.Further distribution analysis of the protein domains revealed that missense mutations were more common in the pore region and voltage sensor(231 mutations per 100 amino acids,respectively),and the protein truncation mutations were distributed evenly among the domains.Conclusions SCN1A mutations tend to cluster at distinct sites,depending on the characteristic CpG dinucleotides,exons,and functional domains.Higher mutation density in particular regions,such as exon 22 and exon 4,ofers promising targets for therapeutic genetic interventions.展开更多
Bulk power systems show increasingly significant frequency spatial distribution characteristics(FSDCs),leading to a huge difference in the frequency response between regions.Existing uniform-frequency models based on ...Bulk power systems show increasingly significant frequency spatial distribution characteristics(FSDCs),leading to a huge difference in the frequency response between regions.Existing uniform-frequency models based on analytical methods are no longer applicable.This paper develops a reduced-order bus frequency response(BFR)model to preserve the FSDC and describe the frequency response of all buses.Its mathematical equation is proved to be isomorphic to the forced vibration of a mass-spring-damper system,and the closed-form solution(CFS)of the BFR model is derived by the modal analysis method and forced decoupling method in vibration mechanics.The correla tion between its mathematical equation and the state equation for small-signal stability analysis is discussed,and related pa rameters in the CFS are defined by the eigen-analysis method without any additional devices or tools.Case studies show that the proposed reduced-order BFR model and its CFS can im prove the solution accuracy while keeping the solution speed within milliseconds,which can preserve the significant FSDC of bulk power systems and represent a normalized mathematical description of distinct-frequency models.展开更多
基金supported by the National High Technology Research and Development Program (‘863’ Program) of China under contract No. 2012AA091701the Fundamental Research Fund for the Central University of China under the contract No. 2012212020211
文摘This study was conducted on the spatial distribution characteristics of surface tidal currents in the southwestern Taiwan Strait based on the quasi-harmonic analysis of current data obtained by two high frequency surface wave radar(HFSWR) systems. The analysis shows that the tidal current pattern in the southwestern Taiwan Strait is primarily semi-diurnal and influenced significantly by shallow water constituents. The spatial distribution of tidal current ellipses of M2 is probably affected by the interaction between two different systems of tide wave, one from the northern mouth of Taiwan Strait and the other from the Bashi Channel. The directions of the major axes of M2 tidal current ellipses coincide roughly with the axis of the Taiwan Strait. The spatial distribution of the magnitudes of the probable maximum current velocity(PMCS) shows gradual increase of the velocity from northeast to southwest, which is in accordance with the spatial distribution of the measured maximum current velocity(MMCS). The directions of the residual currents are in accordance with the direction of the prevailing monsoon wind at the Taiwan Strait and the direction of the Taiwan warm current during summer. The bathymetry also shows a significant effect on the spatial distribution characteristics of tidal currents.
基金funded by the special project of the National Science&Technology Pillar Program during the Twelfth "Five-year Plan" Period(2012BAK19B02-05-02)
文摘By the aftershock frequency estimation method based on the calculation of coseismic static Coulomb stress changes and rate-and state-dependent fault constitutive law,we calculate the frequency of "direct "aftershocks of the Wenchuan earthquake related to coseismic static Coulomb stress changes in its aftershock zone and the areas nearby.It shows that the frequency is significantly lower than the truth in the main rupture zone,especially in the southern rupture zone,due to the decrease of stress level on the rupture plane of the main shock resulting from coseismic Coulomb stress change.The study also shows that the effect of the Coulomb stress change on the duration of aftershock activity is associated with the lower limit magnitude.The duration is about 15-16 months for aftershocks above ML4.0,and close to 60 months for aftershocks above ML3.5.In this period,the ratio of the"direct"aftershocks caused by coseismic Coulomb stress change ranges between 44.7% to48.6%,which suggests that,even in the "effective"period of coseismic Coulomb stress changes,about half of the aftershocks on the main shock rupture plane are independent of coseismic Coulomb stress changes.It is pointed out that those aftershocks may be related to the afterslip or the viscoelastic relaxation,which are time dependent cases.
基金funded by Research Foundation of China Association Against Epilepsy(CU-2024-042)Medical Scientifc Research Foundation of Guangdong Province(A2024536)+1 种基金the National Natural Science Foundation of China(Grant No.82071548,Grant No.82301639 and Grant No.82201609)Guangzhou Medical University Student Innovation Ability Promoting Program(Grant No.2022A045 and Grant No.02-408-240603131135).
文摘Background SCN1A is the most well-recognized and commonly mutated gene related to epilepsy.This study analyzed the characteristic spatial and frequency distributions of SCN1A mutations,aiming to provide important insight into the mutagenesis etiopathology of SCN1A-associated epilepsy.Methods Epilepsy-associated SCN1A variants were retrieved from the SCN1A mutation database,the HGMD database,and literature reviews.The base substitutions,mutation frequencies in CpG dinucleotides,and spatial distributions of mutations in terms of exons and structural domains were analyzed.Results A total of 2621 SCN1A variants were identifed in 5106 unrelated cases.The most common type was missense mutation,followed by frameshift mutations and splice site mutations.Among the missense mutations,transitions within CpG dinucleotides were much more recurrently identifed than transitions within non-CpG dinucleotides,and the most common type was the G>A transition.Among the nonsense mutations,the most predominant type of single-base substitution was the C>T transition,among which 75.3%(235/312)were within CpG sites.The most common“hotspot”codons for missense mutations were codons 101,946,and 1783;while for nonsense mutations it was codon 712.One-base deletion or insertion was the most common type of frameshift mutation,causing protein truncation.The three most common frameshift mutations were c.5536_5539delAAAC,c.4554dupA,and c.5010_5013delGTTT.Splice mutations were the most frequently identifed in exon 4 with a hotspot site c.602+1G>A.The spatial distribution of missense mutations showed that exons 22 and 4 had the highest mutation density(111 and 84 mutations per 100 bp,respectively),and exon 12 had the lowest mutation density,with 4 mutations per 100 bp.Further distribution analysis of the protein domains revealed that missense mutations were more common in the pore region and voltage sensor(231 mutations per 100 amino acids,respectively),and the protein truncation mutations were distributed evenly among the domains.Conclusions SCN1A mutations tend to cluster at distinct sites,depending on the characteristic CpG dinucleotides,exons,and functional domains.Higher mutation density in particular regions,such as exon 22 and exon 4,ofers promising targets for therapeutic genetic interventions.
基金supported in part by the National Natural Science Foundation of China(No.U22A20223).
文摘Bulk power systems show increasingly significant frequency spatial distribution characteristics(FSDCs),leading to a huge difference in the frequency response between regions.Existing uniform-frequency models based on analytical methods are no longer applicable.This paper develops a reduced-order bus frequency response(BFR)model to preserve the FSDC and describe the frequency response of all buses.Its mathematical equation is proved to be isomorphic to the forced vibration of a mass-spring-damper system,and the closed-form solution(CFS)of the BFR model is derived by the modal analysis method and forced decoupling method in vibration mechanics.The correla tion between its mathematical equation and the state equation for small-signal stability analysis is discussed,and related pa rameters in the CFS are defined by the eigen-analysis method without any additional devices or tools.Case studies show that the proposed reduced-order BFR model and its CFS can im prove the solution accuracy while keeping the solution speed within milliseconds,which can preserve the significant FSDC of bulk power systems and represent a normalized mathematical description of distinct-frequency models.
