Reliable end-to-end messaging in which tracking and acknowledgement information are contained in the electronic message that is visible to layers above the transport layer, thereby being independent of what transport protocols, and whether different transport protocols, are used to communicate between the two end points. The second curling unit is for curling a sheet which has passed the first curling unit in a second direction which is opposite to the first direction. The actuatorblocking device includes a body configured to move between a first position in the SAFE arrangement and a second position in the FIRE arrangement, an aperture extending through the body, and an actuator. The budgetary ledger may further include a core to enable generation of the budgetary ledger document, and an extension to define rules associated with generation of the budgetary ledger document. , subzones, and one of subzones is selected. At least a portion of the mobile kerogen-based product is recovered.