Related terms: PVD, peripheral arterial disease, PAD, venous thrombosis, deep vein thrombosis, DVT. Peripheral vascular disease (PVD) involves damage to or blockage in the blood vessels distant from your heartâthe peripheral arteries and veins.Your peripheral arteries and veins carry blood to and from your arm and leg muscles and the organs in and below your stomach area.hen PVD affects only the arteries and not the veins, it is called peripheral arterial disease (PAD). The main forms that PVD may take include blood clots (for example, deep vein thrombosis or DVT), swelling (inflammation), or narrowing and blockage of the blood vessels.
THE VELOCITY OF LIGHT AND MAXWELL'S CONSTANT. The use of the velocity of light, or more generally, the velocity of propagation in vacuum of the electromagnetic waves as a fundamental constant, comes from James Maxwell's Electromagnetic Theory.
The conclusion is that a photon with rest mass of zero and speed of c can have any value of energy. This is what is observed (you can have a low energy radio-frequency photon or a high energy x-ray photon but they all have zero rest mass and travel at the same speed).