Concurrency in Play 2.1 or above

I've read a few tutorials on how to deal with concurrency in Play and found some examples:

Asynchronous Job

import scala.concurrent.{ExecutionContext, future}

def sendEmailAsync(from: String, to: String, subject: String, body: String) = {
  import ExecutionContext.Implicits.global // in scala.concurrent

  future {
    EmailHelper.sendEmail(from, to, subject, body)
  }
}

Scheduled Job

import play.api.libs.concurrent.{Akka, Execution}

def sendEmailOnSchedule(from: String, to: String, subject: String, body: String) = {
  import scala.concurrent.duration._
  import Execution.Implicits.defaultContext // in play.api.libs.concurrent

  Akka.system.scheduler.scheduleOnce(10 seconds) {
    EmailHelper.sendEmail(from, to, subject, body)
  }
}

Well, I'm a bit confused... the first example uses scala.concurrent.ExecutionContext.Implicits.global while the second example uses play.api.libs.concurrent.Execution.Implicits.defaultContext. Why? Could someone explain me what is going on behind the scene?