Radioactive tracer such as a cell or tissue, or as a flow tracer to track fluid flow. Radioactive tracers are also used to determine the location of fractures created by hydraulic fracturing in natural gas production. Radioactive tracers form the basis of a variety of imaging systems, such as, PET scans, SPECT scans and technetium scans. Radiocarbon dating uses the naturally occurring carbon-14 isotope as an isotopic label. Isotopes of a chemical element differ only in the mass number. For example, the isotopes of hydrogen can be written as H, H and H, with the mass number at top left. When the
Ixcateopan (archaeological site) de productos derivados del algodón, materia prima que debió ser la principal fuente de abasto y de culto en la región. The archaeological zone consists of a series of overlays built on a natural elevation of the terrain, which occupies approximately 5 thousand square meters. Construction materials employed include: stone slabs, marble, limestone, boulders; and stucco and red paint used for finishing. Ceramic artifacts are a large and important group of samples found, generally mentioned in archaeological reports, serve to describe as well as chronological placement of sites, although seldom are investigation and study specific subjects The typical ceramics used