Polarization (waves)
Polarization (also polarisation) is a property applying to transverse waves that specifies the geometrical orientation of the oscillations. In a transverse wave, the direction of the oscillation is perpendicular to the direction of motion of the wave. A simple example of a polarized transverse wave is vibrations traveling along a taut string "(see image)"; for example, in a musical instrument like a guitar string. Depending on how the string is plucked, the vibrations can be in a vertical direction, horizontal direction, or at any angle perpendicular to the string. In contrast, in longitudinal waves, such as sound waves in a liquid or gas, the displacement of the particles in the oscillation is always in the direction of propagation, so these waves do not exhibit polarization. Transverse waves that exhibit polarization include electromagnetic waves such as light and radio waves, gravitational waves, and transverse sound waves (shear waves) in solids. In some types of transverse waves, the wave displacement is limited to a single direction, so these also do not exhibit polarization; for example, in surface waves in liquids (gravity waves), the wave displacement of the particles is always in a vertical plane.
Polarization (economics)
Because polarization appears similar in 16 European countries as well as the U.S. it seems likely that similar forces affect these shared economic developments. Loss of American manufacturing jobs to overseas global competitors has removed many middle skill jobs. Structural changes with more investment in robotics has removed other middle skill jobs globally, but not the lowest skill or the highest skill. As computers become more competent, this may change. Changes in education in the Third World, with increased education levels in the rest of the world compared to levels in industrial nations, has affected highly industrial economies. Unionization has mixed effects on polarization, since it tends to raise wages at all levels, but reduces the differences between managerial and other employees. The decline in unionization in America may increase polarization slightly. Globalization also lowers wages across the board.The most powerful causes are the redistributive effects of government, through laws such as those that discourage unionization, determine corporate governance, and limit the extent of monopoly rents. These laws generally are plutocratic and accrue benefit to those at the top, at the expense of those in the middle, driving many of the latter into the bottom. As an example of how polarization is affected by labor demand, rather than skill distributions, changing patterns of employment and earnings show strong correlations between wages and the proportion of a skill group employed. When fewer are employed, the wages go down rather than up as simple supply and demand would predict. Another factor is the levelling off of the supply of college graduates after the 1970s in the US and the consequent increase in the wage gap between college graduates and high school graduates. Whether this is also occurring in other industrial countries is not so clear.