Describes how COPD, or chronic obstructive pulmonary disease, is a progressive disease that makes it hard to breathe. Details the symptoms of COPD. Shows how the disease works in the lungs. Explains how progress of the disease can be slowed.
Eratosthenes of Cyrene was a Greek mathematician, geographer, poet, astronomer, and music theorist. He was a man of learning, becoming the chief librarian at the Library of Alexandria. He invented the discipline of geography, including the terminology used today. He is best known for being the first person to calculate the circumference of the Earth, which he did by comparing altitudes of the mid-day sun at two places a known North-South distance apart. His calculation was remarkably accurate. H
Copernicus adapted physics to the demands of astronomy, believing that the principles of Ptolemy's system were incorrect, not the math or observations. He was the first person in history to create a complete and general system, combining mathematics, physics, and cosmology. (Ptolemy, for instance, had treated each planet separately.) Copernicus's system was taught in some universities in the 1500s but had not permeated the academic world until approximately 1600.