With RRMS, the patient experiences relapses (attacks, exacerbations, or flare-ups) during which there are increased symptoms and/or a worsening of neurologic function, followed by partial or complete recovery (or remission). Much more common: RRMS is much more common than progressive courses of MS, which only affect 10% to 15% of patients.
Vapor density is the density of a vapour in relation to that of hydrogen.It may be defined as mass of a certain volume of a substance divided by mass of same volume of hydrogen. vapor density = mass of n molecules of gas / mass of n molecules of hydrogen.Therefore:vapour density = molar mass of gas / molar mass of H 2.or example, acetone has a vapour density of 2 in relation to air. That means acetone vapour is twice as heavy as air. This can be seen by dividing the molecular weight of Acetone, 58.1 by that of air, 28.97, which equals 2.
What do cosmologists mean by the critical density of the Universe? Critical density is the value at which the Universe is at balance, and expansion is stopped. This value is estimated as (1-3) * 10^-26 kg/m^3. This is related to the cosmic density parameter in many ways; this term describes the ratio of the actual density value of the Universe to the critical density value. If the ratio is one, then the Universe is at balance, and the Universe is flat.