Karyomorphology of three endemic plants(Brassicaceae:Euclidieae and Arabideae)from the Qinghai-Tibet Plateau and its significance

In the paper,chromosome number and karyotype of three endemic genera from China are reported for the first time.Our results show that Anzhengxia yechengnica has a karyotype formula2 n=2 x=14=6 m+8 sm and belongs to Stebbins-3 A;Shangrilaia nana karyotype formula is2 n=2 x=14=10 m+4 sm(2 sat) and belongs to Stebbins-1 A;Baimashania pulvinata karyotype formula is 2 n=2 x=16=12 m(2 sat)+4 sm and belongs to Stebbins-1 A.Anzhengxia and Shangrilaia are monospecific genera belonging to tribe Euclidieae and both have a basic chromosome x=7.Baimashania,which belongs to tribe Arabideae,has two species which have a basic chromosome x=8.The implications of these cytological data are compared with morphological support and the implications for each tribe are discussed.We also summarize chromosomal number variation and its systematic implications of two tribes from the Qinghai-Tibet Plateau.

Karyotypes of nineteen species of Asteraceae in the Hengduan Mountains and adjacent regions

The Hengduan Mountains region is a biodiversity hotspot. In this study, we report the karyotypes of 19 species(21 populations) of Asteraceae from this region, 14 of which are reported for the first time. We also examined polyploidy in Asteraceae plants and summarized karyotype data in the literature for 69 congeneric taxa. In these genera, there were five different ploidy levels in the region, though the most dominant was diploid(73.08%). There is no direct evidence that ploidy level and karyotype asymmetry are associated with the distribution of recorded Asteraceae species from the Hengduan Mountains. This suggests that polyploidy(26.92%) may not play an important role in the evolutionary history of these plants, even though, among these genera, the ratio of paleopolyploidy was high(46.15%).

A Bio-inspired Soft Robotic Arm： Kinematic Modeling and Hydrodynamic Experiments

Soft robotics has several promising properties for aquatic applications, such as safe interaction with environments, lightweight, low cost, etc. In this paper, we proposed the kinematic modeling and hydrodynamics experiments of a soft robotic arm with 3D locomotion capacity. We developed a mathematical model that incorporates the angle correction, as well as the open-loop model-based motion control. The model could precisely predict the three-dimensional （3D） movement, and the location error is less than 5.7 mm in different attitudes. Furthermore, we performed the hydrodynamic investigations and simultaneously measured the hydrodynamic forces and the wake flows at different amplitudes （50 mm, 100 mm, 150 mm, 200 mm） and frequencies （0.3 Hz, 0.4 Hz, 0.5 Hz） of the soft arm. Surprisingly, we found that the magnitudes of the hydrodynamic force （〈1 N） and the torques （〈0.08 N-m） of dynamically moving soft arm were tiny, which leads to negligible inertial effect for the underwater vehicle than those of the traditional rigid underwater manipulator. Finally, we demonstrated underwater picking and placing tasks of the soft manipulator by using a computer program that controls the tip attitude and velocity. This study may inspire future underwater manipulators that have properties of low-inertial, low power cost and can safely interact with the aauatic environments.

Linear Acceleration of an Undulatory Robotic Fish with Dynamic Morphing Median Fin under the Instantaneous Self-propelled Condition

Fish commonly execute rapid linear accelerations initiated during steady swimming,yet the function of the median fins during this process is less understood.We find that the erection/folding time(from the starting time of the linear acceleration(0 s)to the starting time of the folding movement of the fin),as well as the spreading area of the median fins,actively change during the linearacceleration of the live largemouth bass(Micropterus salmoides).To better understand the influence of the folding time and the area change of the median fins on the linear acceleration,we implemented an undulatory biomimetic robotic fish with soft median fins that can be programmed to erect and fold,just like a live fish.To characterize the acceleration performance of the robotic fish,we developed a"self-propelled"experiment technique based on the Kalman filter and Proportional-Integral-Derivative(PID)control algorithm.The experiments on the robotic fish show the acceleration induced by fully-erected median fins increases by 46.3%.Fully-erected median fins positively contribute to propulsion primarily at the onset stage of the linear acceleration while result in a significant decrease in steady swimming speed by 25%,which suggests a large drag force is induced at the steady swimming stage due to the enlarged wetted area.Parametric sweeping experiments on erection/folding time and spreading area demonstrate a proper combination of the erection/folding time and the spreading area enhances the mean linear acceleration by up to 85%.Particle Image Velocimetry(PIV)results reveal that the vortexes shed by the erected dorsal fin are stronger than those shed by the folded fin.As the acceleration process progresses,the thrust generated by the dorsal fins gradually is weakened until only resistance is generated in the end.Our findings may shed light on the realization of controllable surfaces on high performance fish-inspired robotic systems in the future.