1 For best results from your flask, before use, pre-fill for about 3 minutes, using either hot water for hot drinks or cold water for chilled drinks. 2  Never use a microwave or conventional oven to pre-heat your flask.  If your flask has not been used for some time, rinse with warm water to remove any residual odours.
2. : the degree to which something is prevalent; especially: the percentage of a population that is affected with a particular disease at a given time.
Prevalence is the number of people in a population that have a condition relative to all of the people in the population. Prevalence is typically shown as a percent (e.g. 1%) or a proportion (e.g. 1 in 100). E-mail Your Friends. Children with autism spectrum disorder are not being diagnosed as early as they could be.