See Also: Disorder, seasonal affective (SAD)(health)
seasonal affective disorder(dictionary)
seasonal affective disorder (SAD)(encyclopedia)
seasonal affective disorder(medicine)
Affective disorder, seasonal (SAD)(health)
affective disorder(encyclopedia)
affective personality disorder(medicine)
Bipolar affective disorder(health)
seasonal(dictionary)
seasonal(dictionary)

engine (sh) and seasonal affective disorder (medicine)


engine (sh)




Machine that can convert any of various forms of energy into mechanical power or motion.

The steam engines developed during the Industrial Revolution to power stationary machinery were modified in the 19th century to propel locomotives and ships, and were joined later by steam turbines. Internal-combustion engines were developed by Nikolaus Otto and Rudolf Diesel in the late 19th century. Gas turbines and rocket engines came into use in the later 20th century. See also diesel engine, gasoline engine, jet engine, rocket, and rotary engine.


seasonal affective disorder (medicine)


seasonal affective disorder


A syndrome characterised by depressions that recur annually at the same time each year, usually during the winter months. Other symptoms include anxiety, irritability, decreased energy, increased appetite (carbohydrate cravings), increased duration of sleep, and weight gain. Sad (seasonal affective disorder) can be treated by daily exposure to bright artificial lights (phototherapy), during the season of recurrence.