: Methane is emitted during the production and transport of coal, natural gas, and oil. Methane emissions also result from livestock and other agricultural practices and by the decay of organic waste in municipal solid waste landfills.
Traumatic Brain Injury (TBI) - Levels of Severity. Mild TBI. Loss of consciousness is very brief, usually a few seconds or minutes. Loss of consciousness does not have to occur - the person may be dazed or confused. Testing and scans of the brain may appear normal. Most common: 75%-85% of all brain injuries are mild.
When the results of a head injury are worse than mild TBI, or concussion, the injury may be classified as moderate or severe TBI. The factors used to define moderate TBI are: 1  A loss of consciousness that lasts for more than 30 minutes but less than 24 hours. 2  Memory loss after the traumatic event, called post-traumatic amnesia or PTA, lasting for 24 hours to seven days.