Abstract: Guanidine derivatives are provided useful for promoting growth, repair and regeneration of a neuronal axon and for treating neuropathies and myopathies. The compounds have the formula: ##STR1## wherein R.sub.1 is an isopropyl radical, a benzyl radical which is optionally substituted by one or more (C.sub.1 -C.sub.6)alkoxy radicals or a radical: ##STR2## R.sub.2, R.sub.3 and R.sub.

Abstract: Compounds are provided useful for promoting growth, repair and regeneration of a neuronal axon and for treating neuropathies and myopathies having formula I ##STR1## wherein R.sub.2, R.sub.3 and R.sub.4 together with the nitrogen atoms to which they are attached forms a heterocyclic ring.

Abstract: A method and apparatus for automatically actuating roving bobbin exchange operations in a textile yarn spinning apparatus. The spinning stations are divided into equal groups and a roving bobbin exchange operation is actuated at each group by a suitable control system, e.g. a microprocessor, as a function of the number of spinning stations of the group identified as down with uncorrectable yarn breaks and as a further function of the total elapsed operating time of the group since the last bobbin exchange operation.

Abstract: The steering or control force for operating a steering column in an aircraft, especially in a rotary wing aircraft, is stabilized. The steering column influences through an articulated steering or control linkage the elevator assembly or the rotor blade adjustment, whereby a signal is employed which is dependent on the measured flight speed. It is necessary to signal to the pilot at all times how the steering column must be moved. Such signalling must be definite and free of any disturbing influences and the pilot must receive such signalling through the steering column manual force which is a force reacting to the operation of the steering column. For this purpose a speed dependent signal is supplied to a servomotor. This signal rises with the flight speed at least above a preselectable threshold value. The servomotor in turn controls the tensioning state of a spring which is pivoted at one end to the steering column and at the other end to the displacement member of the servomotor.

Abstract: The control of the longitudinal or pitching stability of aircraft is imprd by providing a corrected control characteristic for the correction adjustment drive which is interposed between the pilot operated control stick and the main control drive, for example for the blade angle adjustment in a helicopter or for the elevator adjustment in fixed wing aircraft. A control linkage (2) is connected on one end to a main control drive (4) for the elevator or rotor blade adjustment and at its other end to the control stick (1). The correction adjustment drive (3) is interposed in the control linkage (2). A displacement pickup (5) measures the control displacement of the control linkage (2) and a flight speed pickup (6) measures the flight speed.

Abstract: Control force errors are automatically eliminated in aircraft, especially licopters. Such errors may occur because of disturbing forces that act on a control stick (1) for the elevator and/or rotor blade adjustment. The following features are combined. A main control drive (3) for the adjusting of the elevators and/or rotor blades is connected through a control linkage (2) with the control stick (1). A spring box (5) with a pretensioned spring (17) is connected through a control rod (14) to the control stick (2) and to one end of the spring box (5). A trimming rod (15) of a trimming motor (4) is operatively connected to the other end of the spring box (5). To compensate the disturbing forces caused by the inertial mass forces acting upon the control stick (1) as much as possible there are further provided two displacement pickups (6) and (7) or a single displacement difference forming pickup (16). A first summing circuit (8) receives the output signals from the two pickups (6, 7).

Abstract: A flight control system including a mechanical control link (10) may have herent destabilizing characteristics. Such inherent characteristics may be caused by play in the mechanical control link of the system, by friction losses, by elasticity phenomena, and by hysteresis effects. For neutralizing such inherent effects a flight control system is provided with an internal control circuit (20) having an integration stage (36) followed by an amplifier (38) providing a control correction signal (y) at its output. The control correction signal (y) is supplied to an electro-hydraulic control drive (40) which applies the correction signal (y) to a signal combining stage (42) at the input of the mechanical control link (10).