Discrete Mathematics/Functions and relations. This article examines the concepts of the function and the relation. A relation is any association or link between elements of one set, called the domain or (less formally) the set of inputs, and another set, called the range or set of outputs.
Sleep deprivation. Sleep deprivation is the condition of not having enough sleep; it can be either chronic or acute. A chronic sleep-restricted state can cause fatigue, daytime sleepiness, clumsiness and weight loss or weight gain. It adversely affects the brain and cognitive function.
Sleep Apnea Overview. Sleep apnea occurs when your breathing is disrupted during sleep. Men, overweight people, and people over 40 are at greater risk for sleep apnea. Untreated sleep apnea can cause hypertension, stroke, or heart failure. Erectile Dysfunction and Sleep Apnea.