Vector Fields in Maple. A vector field is described by a function that takes each point of the plane to a vector. > with(linalg): > F := (x,y) -> [-y,x]; We can evaluate this function at a point by plugging in values for x and y , just like we do with functions whose values are scalars.
The survey of U.S. parents finds that out of children participating in Fall and Winter sports, just 60 percent are wearing mouth guards. Taking a closer look at mouth guard usage for some higher-impact sports, the survey shows that for football, just 32 percent of parents report their child wears a mouth guard, for field hockey, just 14 percent. Lacrosse and ice hockey both fall at 11 percent, alongside volleyball. The complete list can be found here.
While all children who use playgrounds are at risk for injury, girls sustain injuries (55%) slightly more often than boys (45%) (Tinsworth 2001). Children ages 5 to 9 have higher rates of emergency department visits for playground injuries than any other age group. Most of these injuries occur at school (Phelan 2001).