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The paper presents an autonomous navigation method for a spacecraft formation flying in the proximity of an asteroid. The measurements from an onboard high resolution camera and a LIDAR are used to estimate the relative position and velocity of the spacecraft with respect to the asteroid. The main innovation is the inclusion of inter-spacecraft measurements provided by the same sensors to evaluate the improvement of navigation performance. Several schemes are constructed to quantify the navigation performance affected by different combinations of measurements, which are obtained from each spacecraft within a 2-spacecraft formation. Unscented Kalman Filter (UKF) is then proposed to simultaneously estimate the position and velocity of each spacecraft with respect to the asteroid. Some examples demonstrate that a significant improvement of the navigation accuracy can be obtained by fusing the inter-spacecraft measurements with the spacecraft-to-asteroid measurements. The robustness of the proposed navigation strategy is then assessed by considering a range of different magnitudes of the noise in measurements and process. [ABSTRACT FROM AUTHOR]

Objective: To analyze retrospectively the karyotypes of amniotic fluid, and to study the relationship between the distortion of chromosome number or structure and fetal abnormalities. Methods" 1 984 pregnant women with the high risks under prenatal screening were asked to test the karyotypes of amniotic fluid in their pregnant weeks of 17 to 23, with the informed consent. Results: In 1984 cases, there were 49 cases (2.47%) with abnormal karyotypes, including 31 cases (1.56%) with the number abnormalities (27 cases with autosome number distortion and 4 cases with sex chromosome number distortion), 12 cases (0.60%) with the structural abnormalities (9 cases with the chromosome balanced translocation and 3 cases with unbalanced translocation) and 6 cases (0.30%) with chimera. There were 226 cases (11.39%) with the chromosomal polymorphism mutation, including 20 cases (1.01%) with 9 chromosome percentric inversion, 78 cases (3.93%) with the satellite and petit polymorphism mutation of D/G group chromosome, 72 cases (3.63%) with the secondary constriction polymorphism mutation and 56 cases (2.82%) with big or small Y chromosome. Conclusions: Karyotype examination of amniotic fluid is very important for the diagnosis of fetal chromosomal diseases, especially for those pregnant women with the high risks under prenatal screening. Besides, it is helpful to evaluate the pregnancy outcomes and fetal genetic health. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the clinical application of the chromosome karyotype of umbilical blood samples in genetic diagnosis. Methods: To analyze retrospectively the data of chromosome karyotype of umbilical blood samples in 2 036 newborns in our hospital from June to December 2013. The chromosome specimen was prepared by the method of conventional peripheral blood lymphocytes culture. Karyotype was analyzed by the G--banding technique. Results: Totally, there were 16 cases (0.79%) of chromosome abnormalities in 2 036 cases, including 13 cases(0.64%) with autosomal abnormalities and 3 cases(0.15%) with sex chromosome abnormalities. There were 3 cases of 21-trisomy(0.15%), a terminal deletion(0.05%), 3 cases of inversion(0.15%), a balanced translocation (0.05%), 3 cases of Robertsonian translocation (0.15%) and two cases of marker chromosome (0.10%) in those autosomal abnormalities. There were 2 cases of 47, XYY (0.10%) and a 46, XX, del (X) (0.05%) in those sex chromosome abnormalities. There were also 181 cases (8.89%) of polymorphic variation karyotypes. Conclusions: We can increase the rate of prenatal diagnosis by improving the prenatal education. Those newborns should be diagnosed early in neonatal phase if pregnant women with high risks did not get prenatal diagnosis. [ABSTRACT FROM AUTHOR]