A convertible computer is equipped with a notebook computer function and a tablet computer function. The sensor element includes a substrate, a first planar-sensor electrode and a second planar-sensor electrode which are formed on andor in the substrate and whereon catcher molecules can be immobilised. The insertion unit is flexible and elongated. , sn of the distance s, respectively. The illustrative embodiments update a rendering of the virtual world artifact in the virtual world based on the rating score. Such non-volatile memory cell further provides two transistors for injecting negative charge into the floating gate during a programming operation, and removing negative charge from the second floating gate transistor during an erase operation.