Abstract: Method for mediating the effects of light on melatonin rhythmicity in mammals and a method of mediating circadian rhythms, effected by the administration of a compound or compounds effective at a 5-HT2c serotonin receptor site. By administration of selected doses of the 5-HT2c receptor active compound it is possible to advance or delay circadian rhythms as measured by the rate of melatonin production or moderation of core body temperature rhythms.

Abstract: A pixel comprises a Field Effect Transistor formed on a gallium arsenide substrate wherein a source (1) of the field effect transistor is a photoresponsive element, a gate of the field effect transistor is shielded from light and acts as a switch to enable/disable readout and a drain (4) of the field effect transistor is connected to a readout line. Also disclosed an X-Y imager formed on a gallium arsenide substrate from a plurality of pixels and a processing area wherein each pixel comprises a photoresponsive source (1), a gate formed from a plurality of metal fingers (7) across the source (1), a drain (4) connected to a readout line and a gate resistor (12) connected in series with the fingers (7). The arrangement of fingers (7) across the source (1) in co-operation with the gate resistor (12) produces an enhanced optical gain.

Abstract: A fluorometer probe head and a method of operating a probe to overcome problems of reflectance.A preferred embodiment for determination of chlorophyll in plant leaves uses a red LED and a green LED consecutively directed to a particular target spot and a photodiode records fluoresced and reflected signals to provide an accurate result.