Blastocyst transfer is advocated to reduce the risk of multiple gestations in pregnancies by assisted reproduction. Nevertheless, there remains the rare inherit possibility of embryo splitting that can result in monoz...Blastocyst transfer is advocated to reduce the risk of multiple gestations in pregnancies by assisted reproduction. Nevertheless, there remains the rare inherit possibility of embryo splitting that can result in monozygotic twins leading to high-order multiples. Also, when a patient is found to have a higher gestation than the number of embryos transferred it calls into question the IVF facility’s competency and credibility. The case report presented such a rare phenomenon of embryo splitting and the clinical consequences precipitated from it. In the patient, two blastocysts were transferred 5 days after transvaginal oocyte retrieval. The pregnancy confirming hCG test did not predict high-order multiples in this case. Early ultrasonography documented trichorionic-quadramnionic gestation. Selective reduction of the monochorionic twins was done at 11 weeks. Dichorionic twin gestation continued uneventful until 22 weeks at which point the patient experienced preterm premature rupture of membranes with subsequent delivery. The pathology report confirmed trichorionic-quadramnionic gestation. The mode of splitting was different for the two embryos one leading to monozygotic dichorionic and the other to monozygotic monochorionic. Furthermore, the implantation was also apparently asynchronous with one implanted considerable later than the other. The first β-hCG value seemingly did not represent the entire initial implementation events otherwise the value would be higher carrying the early signal of high-order multiple.展开更多
MAYBE even rarer than an Elvis sighting in Beijing, eleven sets of quadruplets from eight cities, provinces and autonomous regions gathered together for the first time in Shanghai in May of 1997. Entitled "Let Af...MAYBE even rarer than an Elvis sighting in Beijing, eleven sets of quadruplets from eight cities, provinces and autonomous regions gathered together for the first time in Shanghai in May of 1997. Entitled "Let Affection Fill China--Reunion of Chinese Quadruplets," the sets of four came from Shanghai, Jiangsu, Zhejiang, Fujian, Hunan, Shandong, Ningxia and Hebei. The eldest quadruplets are the four Wei sisters from Shanghai, aged 35;展开更多
ON January 16, 1993, I received a letter from Shan Jiazhi, professor of gynecology and obstetrics at Shandong Provincial Hospital. In his letter, Shan informed me that a woman would soon give birth to quadruplets and ...ON January 16, 1993, I received a letter from Shan Jiazhi, professor of gynecology and obstetrics at Shandong Provincial Hospital. In his letter, Shan informed me that a woman would soon give birth to quadruplets and asked me to quickly come to the hospital. In his office, Professor Shan produced two X-rays of the lying-in woman. "This woman, Su Lixin, is a worker with the Jinan No. 1 Machine Tool Factory. Since she was hospitalized, we’ve applied modern comprehensive measures to control the occurrence of complications and have striven for international standards for the gestational period reaching or surpassing 37 weeks." He then told me that in the United States,展开更多
Traditional hand-crafted features for representing local image patches are evolving into current data-driven and learning-based image feature, but learning a robust and discriminative descriptor which is capable of co...Traditional hand-crafted features for representing local image patches are evolving into current data-driven and learning-based image feature, but learning a robust and discriminative descriptor which is capable of controlling various patch-level computer vision tasks is still an open problem. In this work, we propose a novel deep convolutional neural network(CNN) to learn local feature descriptors. We utilize the quadruplets with positive and negative training samples, together with a constraint to restrict the intra-class variance, to learn good discriminative CNN representations. Compared with previous works, our model reduces the overlap in feature space between corresponding and non-corresponding patch pairs, and mitigates margin varying problem caused by commonly used triplet loss. We demonstrate that our method achieves better embedding result than some latest works, like PN-Net and TN-TG, on benchmark dataset.展开更多
Image distortion caused by the angular misalignment of quadrupole magnets in high-energy electron radiography has been studied systematically.We propose that the distortion originates from the coupling of the electron...Image distortion caused by the angular misalignment of quadrupole magnets in high-energy electron radiography has been studied systematically.We propose that the distortion originates from the coupling of the electron motions in the transverse directions,based on a theoretical analysis and the transfer-matrix method.The relative angular rotation between the second and third magnetic quadrupoles was identified as the main contributor to image distortion.This was verified by both a beam-dynamics simulation and experiments.Different strategies to mitigate this image distortion are also explored,including magnets online tuning,higher beam energy and larger magnification factor.This study provides criteria for designing experiments and paves the way for achieving higher image precision.展开更多
The studies in China on the formation of the summertime subtropical anticyclone on the climate timescale are reviewed. New insights in resent studies are introduced. It is stressed that either in the free atmosphere o...The studies in China on the formation of the summertime subtropical anticyclone on the climate timescale are reviewed. New insights in resent studies are introduced. It is stressed that either in the free atmosphere or in the planetary boundary, the descending arm of the Hadley cell cannot be considered as a mechanism for the formation of the subtropical anticyclone. Then the theories of thermal adaptation of the atmosphere to external thermal forcing and the potential vorticity forcing are developed to understand the formation of the subtropical anticyclone in the three-dimensional domain. Numerical experiments are designed to verify these theories. Results show that in the boreal summer, the formation of the strong South Asian High in the upper troposphere and the subtropical anticyclone over the western Pacific in the middle and lower troposphere is, to a great extent, due to the convective latent heating associated with the Asian monsoon, but affected by orography and the surface sensible heating over the continents. On the other hand, the formation of the subtropical anticyclone at the surface over the northern Pacific and in the upper troposphere over North America is mainly due to the strong surface sensible heating over North America, but affected by radiation cooling over the eastern North Pacific. Moreover, in the real atmosphere such individual thermal forcing is well organized. By considering the different diabatic heating in synthesis, a quadruple heating pattern is found over each subtropical continent and its adjacent oceans in summer. A distinct circulation pattern accompanies this heating pattern. The global summer subtropical heating and circulation may be viewed as 'mosaics' of such quadruplet heating and circulation patterns respectively. At last, some important issues for further research in understanding and predicting the variations of the subtropical anticyclone are raised.展开更多
文摘Blastocyst transfer is advocated to reduce the risk of multiple gestations in pregnancies by assisted reproduction. Nevertheless, there remains the rare inherit possibility of embryo splitting that can result in monozygotic twins leading to high-order multiples. Also, when a patient is found to have a higher gestation than the number of embryos transferred it calls into question the IVF facility’s competency and credibility. The case report presented such a rare phenomenon of embryo splitting and the clinical consequences precipitated from it. In the patient, two blastocysts were transferred 5 days after transvaginal oocyte retrieval. The pregnancy confirming hCG test did not predict high-order multiples in this case. Early ultrasonography documented trichorionic-quadramnionic gestation. Selective reduction of the monochorionic twins was done at 11 weeks. Dichorionic twin gestation continued uneventful until 22 weeks at which point the patient experienced preterm premature rupture of membranes with subsequent delivery. The pathology report confirmed trichorionic-quadramnionic gestation. The mode of splitting was different for the two embryos one leading to monozygotic dichorionic and the other to monozygotic monochorionic. Furthermore, the implantation was also apparently asynchronous with one implanted considerable later than the other. The first β-hCG value seemingly did not represent the entire initial implementation events otherwise the value would be higher carrying the early signal of high-order multiple.
文摘MAYBE even rarer than an Elvis sighting in Beijing, eleven sets of quadruplets from eight cities, provinces and autonomous regions gathered together for the first time in Shanghai in May of 1997. Entitled "Let Affection Fill China--Reunion of Chinese Quadruplets," the sets of four came from Shanghai, Jiangsu, Zhejiang, Fujian, Hunan, Shandong, Ningxia and Hebei. The eldest quadruplets are the four Wei sisters from Shanghai, aged 35;
文摘ON January 16, 1993, I received a letter from Shan Jiazhi, professor of gynecology and obstetrics at Shandong Provincial Hospital. In his letter, Shan informed me that a woman would soon give birth to quadruplets and asked me to quickly come to the hospital. In his office, Professor Shan produced two X-rays of the lying-in woman. "This woman, Su Lixin, is a worker with the Jinan No. 1 Machine Tool Factory. Since she was hospitalized, we’ve applied modern comprehensive measures to control the occurrence of complications and have striven for international standards for the gestational period reaching or surpassing 37 weeks." He then told me that in the United States,
基金supported by the Natural Science Foundation of Zhejiang Province(No.Y16F020023)
文摘Traditional hand-crafted features for representing local image patches are evolving into current data-driven and learning-based image feature, but learning a robust and discriminative descriptor which is capable of controlling various patch-level computer vision tasks is still an open problem. In this work, we propose a novel deep convolutional neural network(CNN) to learn local feature descriptors. We utilize the quadruplets with positive and negative training samples, together with a constraint to restrict the intra-class variance, to learn good discriminative CNN representations. Compared with previous works, our model reduces the overlap in feature space between corresponding and non-corresponding patch pairs, and mitigates margin varying problem caused by commonly used triplet loss. We demonstrate that our method achieves better embedding result than some latest works, like PN-Net and TN-TG, on benchmark dataset.
基金supported by the National Natural Science Foundation of China(Nos.12005211,12075192).
文摘Image distortion caused by the angular misalignment of quadrupole magnets in high-energy electron radiography has been studied systematically.We propose that the distortion originates from the coupling of the electron motions in the transverse directions,based on a theoretical analysis and the transfer-matrix method.The relative angular rotation between the second and third magnetic quadrupoles was identified as the main contributor to image distortion.This was verified by both a beam-dynamics simulation and experiments.Different strategies to mitigate this image distortion are also explored,including magnets online tuning,higher beam energy and larger magnification factor.This study provides criteria for designing experiments and paves the way for achieving higher image precision.
基金supported by the Chinese Academy of Sciences(Grant No.ZKCX2 SW-210)the National Natural Science Foundation of China(Grant Nos.40135020,40221503,and 40023001).
文摘The studies in China on the formation of the summertime subtropical anticyclone on the climate timescale are reviewed. New insights in resent studies are introduced. It is stressed that either in the free atmosphere or in the planetary boundary, the descending arm of the Hadley cell cannot be considered as a mechanism for the formation of the subtropical anticyclone. Then the theories of thermal adaptation of the atmosphere to external thermal forcing and the potential vorticity forcing are developed to understand the formation of the subtropical anticyclone in the three-dimensional domain. Numerical experiments are designed to verify these theories. Results show that in the boreal summer, the formation of the strong South Asian High in the upper troposphere and the subtropical anticyclone over the western Pacific in the middle and lower troposphere is, to a great extent, due to the convective latent heating associated with the Asian monsoon, but affected by orography and the surface sensible heating over the continents. On the other hand, the formation of the subtropical anticyclone at the surface over the northern Pacific and in the upper troposphere over North America is mainly due to the strong surface sensible heating over North America, but affected by radiation cooling over the eastern North Pacific. Moreover, in the real atmosphere such individual thermal forcing is well organized. By considering the different diabatic heating in synthesis, a quadruple heating pattern is found over each subtropical continent and its adjacent oceans in summer. A distinct circulation pattern accompanies this heating pattern. The global summer subtropical heating and circulation may be viewed as 'mosaics' of such quadruplet heating and circulation patterns respectively. At last, some important issues for further research in understanding and predicting the variations of the subtropical anticyclone are raised.
