The American black bear lived during the same period as short-faced bears (Arctodus simus and A. pristinus) and the Florida spectacled bear (Tremarctos floridanus). These Tremarctine bears evolved from bears that had emigrated from Asia to North America 7â8 ma.
A plenum space is a part of a building that can facilitate air circulation for heating and air conditioning systems, by providing pathways for either heated/conditioned or return airflows, usually at greater than atmospheric pressure.
1 Plenum chamber, a chamber intended to contain air, gas, or liquid at positive pressure. 2  Plenism, or Horror vacui (physics) the concept that nature abhors a vacuum.3  Plenum (meeting) , a meeting of a deliberative assembly in which all members are present; contrast with quorum.lenum may refer to: 1  Plenum chamber, a chamber intended to contain air, gas, or liquid at positive pressure. 2  Plenism, or Horror vacui (physics) the concept that nature abhors a vacuum.