Haosheng Li

The political thought of both Popper and Oakeshott are embodied in how each criticizes rationalist politics. There are two fundamental crises in rationalist politics: The utopianism of seeking perfect ideals and the technical politics of abridging political practices into social engineering. Popper holds a view of “critical rationalism” to recall rational critique to rescue rationalism, then puts forwards a project called “Piecemeal Social Engineering.” Oakeshott takes a view of “intimation in tradition,” and then presents a project named “Civil Association.” Both of Piecemeal Social Engineering and Civil Association overcome the first crisis successfully, but the latter addresses a more effective articulation of the second crisis. Therefore, Civil Association can avoid the plight of rationalist politics more thoroughly than Piecemeal Social Engineering.

Knowledge of three-dimensional structures of each individual particles of asymmetric and flexible proteins is essential in understanding those proteins' functions; but their structures are difficult to determine. Electron tomography provides a tool for imaging a single and unique biological object from a series of tilted angles, but it is challenging to image a single protein for three-dimensional reconstruction due to the imperfect mechanical control capability of the specimen goniometer under both a medium to high magnification and an optimized beam coherence condition. Here, we report a fully mechanical control method for automating ET data acquisition without using beam tilt/shift processes. This method could reduce the accumulation of beam tilt/shift that used to compensate the error from the mechanical control, but downgraded the beam coherence. Our method was developed by minimizing the error of the target object center during the tilting process through a closed-loop proportional-integral control algorithm. The validations by both negative staining and cryo-electron microscopy suggest that this method has a comparable capability to other ET methods in tracking target proteins while maintaining optimized beam coherence conditions for imaging.