Electron microscopes have certain advantages over optical microscopes: The biggest advantage is that they have a higher resolution and are therefore also able of a higher magnification (up to 2 million times). Light microscopes can show a useful magnification only up to 1000-2000 times. This is a physical limit imposed by the wavelength of the light. Electron microscopes therefore allow for the visualization of structures that would normally be not visible by optical microscopy.
berm (plural berms) A narrow ledge or shelf, as along the top or bottom of a slope. A raised bank or path, especially the bank of a canal opposite the towpath. A terrace formed by wave action along a beach. A mound or bank of earth, used especially as a barrier or to provide insulation.
More complex ones have a sturdy substrate made out of rocks or gravel, topped by clay and finally packed with soil. This type of more permanent berm is often used to contain floodwaters, provide a barrier between land belonging to different people, or to keep livestock confined.When well maintained, they can last for centuries and have a profound shaping impact on the landscape that they are constructed in.erm is also the word used to describe the banked turns on dirt tracks for off-road vehicle racing such as Moto-Cross and BMX racing.