A compound of formula M-L-M wherein L is a linker and each M is independently a group of formula is useful in therapy, e. A peripheral interface circuit for an inputoutput node of a computer system includes a first buffer circuit, a second buffer circuit and a bus interface circuit. The access operations of both processors to these memories are coordinated on the basis of the content of the input and output control information memories. Moreover, degree of freedom in a configuration of the support area increases. Upon receiving an approval message sent by the payment control center via the server when the payment control center has successfully completed arrangements for the payment of the product, the portable transaction device generates a printed delivery receipt, and sends delivery confirmation to the server via the communications link when the delivery of the product is completed. The method comprises displaying an animation that indicates to the user when to breathe in and breathe out, receiving a signal from a sensor responsive to the heart beat of the user, processing the received signal to determine heart beat intervals of the user and calculating a measure of heart rate variability of the user from the processed heart beat intervals.