The seismic wave consists of many seismic phases, which contain rich geophysical information from the hypocenter, medium of seismic wave passing through and so on. It is very important to detect and pick these seismic...The seismic wave consists of many seismic phases, which contain rich geophysical information from the hypocenter, medium of seismic wave passing through and so on. It is very important to detect and pick these seismic phases for understanding the mechanism of earthquake, the Earth structure and property of seismic waves. In order to reduce or avoid the loss resulted from the earthquake, one of the important goals of seismic event detecting is to obtain its related information before and after it occurs. Because of the particularity of P wave and S wave the seismic event detecting focuses on distinguishing P and S waves and picking their onset time, it has been becoming one of the research hotspots for many geophysicists to pick the P and S wave arrival accurately and effectively.展开更多
This paper using the dataset of BBFs (bursty bulk flows) observed by two Cluster satellites C1 and C4 studies the difference between onset times of BBFs observed by C1 and C4. It is found that the onset time differenc...This paper using the dataset of BBFs (bursty bulk flows) observed by two Cluster satellites C1 and C4 studies the difference between onset times of BBFs observed by C1 and C4. It is found that the onset time differences of most of BBFs observed by C1 and C4 are smaller than 60 s. The average onset time difference of BBFs of C1 and C4 is 68.5 s. The probabilities of onset time difference of BBFs of C1 and C4 larger than 30 60 90 and 120 s are respectively 55% 35% 27% and 23%. The largest onset time difference of BBFs of C1 and C4 decreases with the increase of earthward component of maximum velocities of BBFs. The onset time difference of BBFs of C1 and C4 results from the velocity inhomogeneity inside the flow channel of BBF which may be produced in propagation path and/or in source region of BBFs. Such a wide range of onset time difference of BBFs suggests that the velocity inhomogeneity inside the flow channel of BBF is various. These results are very important to the current study of substorm research based on THEMIS data because they indicate that it is impossible to determine the onset time of BBF with a single satellite.展开更多
We investigate the onset and the decay of Taylor-Couette flow in finite cylinders, and we report the estimated time scales in the azimuthal section of the flow state transition between the super-critical state and the...We investigate the onset and the decay of Taylor-Couette flow in finite cylinders, and we report the estimated time scales in the azimuthal section of the flow state transition between the super-critical state and the sub-critical state by fitting the numerical result to the solution of the Stuart-Landau equation. The inner cylinder rotates, and the outer cylinder and both end walls of the cylinders are stationary. Near the end walls of the cylinders, the value of the time scale is small. In the inner region, the radial velocity component has a large time scale near the center of the vortices, while the axial velocity component has a large time scale between the vortices.展开更多
Background: The timing of elective repeat cesarean delivery at 38 weeks versus 39 weeks is still a debatable subject, both regarding maternal and neonatal outcomes. In the Saudi context, there is lack of local data to...Background: The timing of elective repeat cesarean delivery at 38 weeks versus 39 weeks is still a debatable subject, both regarding maternal and neonatal outcomes. In the Saudi context, there is lack of local data to aid decision-making regarding the timing of elective repeat cesarean delivery. Objectives: To estimate the rate of spontaneous onset of labor before the planned gestational age for repeat cesarean section in women who were booked at gestational age of (39 0/7 - 39 6/7) weeks (W39) versus (38 0/7 - 38 6/7) weeks (W38) and to compare the rate of maternal composite outcome between these groups. Design: Retrospective cohort. Setting: This study was conducted at King Abdulaziz Medical City, Jeddah, KSA. Method: Delivery registry books were reviewed to identify all deliveries from 1 January 2014 to 31 December 2016 (3 years). All low-risk pregnant women who had 2 or more cesarean deliveries and who met the inclusion criteria were included. Results: A total of 440 women were included of whom 318 (72.3%) were planned for elective cesarean section at W38 gestational age and 122 women at W39 gestational age. Mothers planned at W39 had higher rate of emergency cesarean deliveries versus those planned at W38 (18.0% versus 10.4%, p = 0.030;RR = 13.06), most frequently due to early onset of contractions (16.4% versus 8.2%, p = 0.012;RR = 12.17) or cervical dilatation (11.6% versus 5.4%, p = 0.024, RR = 16.15). No difference in the incidence of individual or composite maternal complications was noted between the two groups. Mother’s age (OR 0.93, p = 0.018) and schedule date at W39 (OR = 1.94, p = 0.028) were independently associated with spontaneous onset of labor before the scheduled gestational age, while no association was found with parity, previous number of spontaneous vaginal deliveries, number of previous cesarean deliveries or interval from last cesarean delivery. Conclusion: Elective cesarean section scheduled at 39 weeks of gestation or beyond carries a higher risk of emergency cesarean section, with no significant increase in maternal complications. The identification of factors associated with spontaneous onset of labor before the planned gestational age should be carefully identified to determine the optimal timing.展开更多
RegCM4.3, a high-resolution regional climate model, which includes five kinds of aerosols(dust, sea salt,sulfate, black carbon and organic carbon), is employed to simulate the East Asian summer monsoon(EASM) from 1995...RegCM4.3, a high-resolution regional climate model, which includes five kinds of aerosols(dust, sea salt,sulfate, black carbon and organic carbon), is employed to simulate the East Asian summer monsoon(EASM) from 1995 to 2010 and the simulation data are used to study the possible impact of natural and anthropogenic aerosols on EASM.The results show that the regional climate model can well simulate the EASM and the spatial and temporal distribution of aerosols. The EASM index is reduced by about 5% by the natural and anthropogenic aerosols and the monsoon onset time is also delayed by about a pentad except for Southeast China. The aerosols heat the middle atmosphere through absorbing solar radiation and the air column expands in Southeast China and its offshore areas. As a result, the geopotential height decreases and a cyclonic circulation anomaly is generated in the lower atmosphere. Northerly wind located in the west of cyclonic circulation weakens the low-level southerly wind in the EASM region. Negative surface radiative forcing due to aerosols causes downward motion and an indirect meridional circulation is formed with the low-level northerly wind and high-level southerly wind anomaly in the north of 25° N in the monsoon area, which weakens the vertical circulation of EASM. The summer precipitation of the monsoon region is significantly reduced,especially in North and Southwest China where the value of moisture flux divergence increases.展开更多
Prevalent cohort studies involve screening a sample of individuals from a population for disease, recruiting affected individuals, and prospectively following the cohort of individuals to record the occurrence of dise...Prevalent cohort studies involve screening a sample of individuals from a population for disease, recruiting affected individuals, and prospectively following the cohort of individuals to record the occurrence of disease-related complications or death. This design features a response-biased sampling scheme since individuals living a long time with the disease are preferentially sampled, so naive analysis of the time from disease onset to death will over-estimate survival probabilities. Unconditional and conditional analyses of the resulting data can yield consistent estimates of the survival distribution subject to the validity of their respective model assumptions. The time of disease onset is retrospectively reported by sampled individuals, however, this is often associated with measurement error. In this article we present a framework for studying the effect of measurement error in disease onset times in prevalent cohort studies, report on empirical studies of the effect in each framework of analysis, and describe likelihood-based methods to address such a measurement error.展开更多
The apolipoprotein E gene ε4 allele is considered a negative factor for neural regeneration in late-onset Alzheimer＇s disease cases. The aim of this study was to establish a non-invasive, rapid method to genotype ap...The apolipoprotein E gene ε4 allele is considered a negative factor for neural regeneration in late-onset Alzheimer＇s disease cases. The aim of this study was to establish a non-invasive, rapid method to genotype apolipoprotein E gene polymorphisms. Genomic DNA from mouth swab specimens was extracted using magnetic nanoparticles, and genotyping was performed by real-time PCR using TaqMan-BHQ probes. Genotyping accuracy was validated by DNA se- quencing. Our results demonstrate 100% correlation to DNA sequencing, indicating reliability of our protocol. Thus, the method we have developed for apolipoprotein E genotyping is accurate and reliable, and also suitable for genotyping large samples, which may help determine the role of the apolipoprotein E ε4 allele in neural regeneration in late-onset Alzheimer＇s disease cases.展开更多
文摘The seismic wave consists of many seismic phases, which contain rich geophysical information from the hypocenter, medium of seismic wave passing through and so on. It is very important to detect and pick these seismic phases for understanding the mechanism of earthquake, the Earth structure and property of seismic waves. In order to reduce or avoid the loss resulted from the earthquake, one of the important goals of seismic event detecting is to obtain its related information before and after it occurs. Because of the particularity of P wave and S wave the seismic event detecting focuses on distinguishing P and S waves and picking their onset time, it has been becoming one of the research hotspots for many geophysicists to pick the P and S wave arrival accurately and effectively.
基金supported by the National Natural Science Foundation of China (Grant Nos. 40931054 and 41174141)National Basic Research Program of China ("973" Program) (Grant No. 2011CB811404)
文摘This paper using the dataset of BBFs (bursty bulk flows) observed by two Cluster satellites C1 and C4 studies the difference between onset times of BBFs observed by C1 and C4. It is found that the onset time differences of most of BBFs observed by C1 and C4 are smaller than 60 s. The average onset time difference of BBFs of C1 and C4 is 68.5 s. The probabilities of onset time difference of BBFs of C1 and C4 larger than 30 60 90 and 120 s are respectively 55% 35% 27% and 23%. The largest onset time difference of BBFs of C1 and C4 decreases with the increase of earthward component of maximum velocities of BBFs. The onset time difference of BBFs of C1 and C4 results from the velocity inhomogeneity inside the flow channel of BBF which may be produced in propagation path and/or in source region of BBFs. Such a wide range of onset time difference of BBFs suggests that the velocity inhomogeneity inside the flow channel of BBF is various. These results are very important to the current study of substorm research based on THEMIS data because they indicate that it is impossible to determine the onset time of BBF with a single satellite.
文摘We investigate the onset and the decay of Taylor-Couette flow in finite cylinders, and we report the estimated time scales in the azimuthal section of the flow state transition between the super-critical state and the sub-critical state by fitting the numerical result to the solution of the Stuart-Landau equation. The inner cylinder rotates, and the outer cylinder and both end walls of the cylinders are stationary. Near the end walls of the cylinders, the value of the time scale is small. In the inner region, the radial velocity component has a large time scale near the center of the vortices, while the axial velocity component has a large time scale between the vortices.
文摘Background: The timing of elective repeat cesarean delivery at 38 weeks versus 39 weeks is still a debatable subject, both regarding maternal and neonatal outcomes. In the Saudi context, there is lack of local data to aid decision-making regarding the timing of elective repeat cesarean delivery. Objectives: To estimate the rate of spontaneous onset of labor before the planned gestational age for repeat cesarean section in women who were booked at gestational age of (39 0/7 - 39 6/7) weeks (W39) versus (38 0/7 - 38 6/7) weeks (W38) and to compare the rate of maternal composite outcome between these groups. Design: Retrospective cohort. Setting: This study was conducted at King Abdulaziz Medical City, Jeddah, KSA. Method: Delivery registry books were reviewed to identify all deliveries from 1 January 2014 to 31 December 2016 (3 years). All low-risk pregnant women who had 2 or more cesarean deliveries and who met the inclusion criteria were included. Results: A total of 440 women were included of whom 318 (72.3%) were planned for elective cesarean section at W38 gestational age and 122 women at W39 gestational age. Mothers planned at W39 had higher rate of emergency cesarean deliveries versus those planned at W38 (18.0% versus 10.4%, p = 0.030;RR = 13.06), most frequently due to early onset of contractions (16.4% versus 8.2%, p = 0.012;RR = 12.17) or cervical dilatation (11.6% versus 5.4%, p = 0.024, RR = 16.15). No difference in the incidence of individual or composite maternal complications was noted between the two groups. Mother’s age (OR 0.93, p = 0.018) and schedule date at W39 (OR = 1.94, p = 0.028) were independently associated with spontaneous onset of labor before the scheduled gestational age, while no association was found with parity, previous number of spontaneous vaginal deliveries, number of previous cesarean deliveries or interval from last cesarean delivery. Conclusion: Elective cesarean section scheduled at 39 weeks of gestation or beyond carries a higher risk of emergency cesarean section, with no significant increase in maternal complications. The identification of factors associated with spontaneous onset of labor before the planned gestational age should be carefully identified to determine the optimal timing.
基金National Key Project of Ministry of Science and Technology of China(2016YFC0203301)National Key Basic Research and Development Project of China(2015CB453201,2013CB430103)+1 种基金National Natural Science Foundation of China(41375058,41530427)Jiangsu Natural Science Key Project of China(BK20150062)
文摘RegCM4.3, a high-resolution regional climate model, which includes five kinds of aerosols(dust, sea salt,sulfate, black carbon and organic carbon), is employed to simulate the East Asian summer monsoon(EASM) from 1995 to 2010 and the simulation data are used to study the possible impact of natural and anthropogenic aerosols on EASM.The results show that the regional climate model can well simulate the EASM and the spatial and temporal distribution of aerosols. The EASM index is reduced by about 5% by the natural and anthropogenic aerosols and the monsoon onset time is also delayed by about a pentad except for Southeast China. The aerosols heat the middle atmosphere through absorbing solar radiation and the air column expands in Southeast China and its offshore areas. As a result, the geopotential height decreases and a cyclonic circulation anomaly is generated in the lower atmosphere. Northerly wind located in the west of cyclonic circulation weakens the low-level southerly wind in the EASM region. Negative surface radiative forcing due to aerosols causes downward motion and an indirect meridional circulation is formed with the low-level northerly wind and high-level southerly wind anomaly in the north of 25° N in the monsoon area, which weakens the vertical circulation of EASM. The summer precipitation of the monsoon region is significantly reduced,especially in North and Southwest China where the value of moisture flux divergence increases.
文摘Prevalent cohort studies involve screening a sample of individuals from a population for disease, recruiting affected individuals, and prospectively following the cohort of individuals to record the occurrence of disease-related complications or death. This design features a response-biased sampling scheme since individuals living a long time with the disease are preferentially sampled, so naive analysis of the time from disease onset to death will over-estimate survival probabilities. Unconditional and conditional analyses of the resulting data can yield consistent estimates of the survival distribution subject to the validity of their respective model assumptions. The time of disease onset is retrospectively reported by sampled individuals, however, this is often associated with measurement error. In this article we present a framework for studying the effect of measurement error in disease onset times in prevalent cohort studies, report on empirical studies of the effect in each framework of analysis, and describe likelihood-based methods to address such a measurement error.
基金supported by two grants from Science,Industry,Trade and Information Technology Commission of Shenzhen Municipality in China,grant No.201002063,JC20110518075 7A
文摘The apolipoprotein E gene ε4 allele is considered a negative factor for neural regeneration in late-onset Alzheimer＇s disease cases. The aim of this study was to establish a non-invasive, rapid method to genotype apolipoprotein E gene polymorphisms. Genomic DNA from mouth swab specimens was extracted using magnetic nanoparticles, and genotyping was performed by real-time PCR using TaqMan-BHQ probes. Genotyping accuracy was validated by DNA se- quencing. Our results demonstrate 100% correlation to DNA sequencing, indicating reliability of our protocol. Thus, the method we have developed for apolipoprotein E genotyping is accurate and reliable, and also suitable for genotyping large samples, which may help determine the role of the apolipoprotein E ε4 allele in neural regeneration in late-onset Alzheimer＇s disease cases.
