It contains minerals such as pyroxene, amphibole, feldspar and 63-68 percent silica. The eruption temperature for dacitic lava is 1,500 to 1,800 degrees Fahrenheit. Dacitic to rhyolitic lava is so dangerous because it contains a high amount of crystals. Mt. Vesuvius erupts according to the Plinian model of eruption.
Nightmares-whether they are just dreams or a sleep disorder-may disrupt normal sleep-wake cycle and create a perception of inadequate sleep or insomnia. There are a lot factors that may trigger insomnia or prevent it from resolving quickly (like temporary jet leg insomnia).ightmares usually occur during REM or dream sleep whereas night terrors usually occur during deeper stages of sleep and may be associated with screaming. Except for the connections noted above there is generally no association between nightmares and night terrors and insomnia.
No one knows why some people have frequent bad dreams. Anxiety, depression, sleep deprivation, post traumatic stress disorder (PTSD), sleep apnea and restless leg syndrome (RLS) have all been blamed. One factor that is often overlooked is medication. A surprising number of drugs can trigger nightmares. People susceptible to this side effect can lose sleep because of their prescriptions. Unfortunately, this complication is not always mentioned. Doctors often think of bad dreams as relatively unimportant, because they are not life threatening.