Age of the Earth research. Most geological samples from Earth are unable to give a direct date of the formation of Earth from the solar nebula because Earth has undergone differentiation into the core, mantle, and crust, and this has then undergone a long history of mixing and unmixing of these sample reservoirs by plate tectonics, weathering and hydrothermal circulation. All of these processes may adversely affect isotopic dating mechanisms because the sample cannot always be assumed to have remained as a closed system, by which it is meant that either the parent or daughter nuclide (a species of atom characterised by the number
Innovation and Its Discontents Innovation and Its Discontents Innovation and Its Discontents: How Our Broken Patent System Is Endangering Innovation and Progress, and What To Do About It is a book () by Adam B. Jaffe and Josh Lerner. Princeton University Press published the book in 2004. The authors of the book outline changes made to the patent system in the United States in the late 1980s and early 1990s which they say has led to a situation in which patents have become extremely powerful economic weapons, and are being issued irresponsibly and at an unreasonable rate. The end result, the authors claim, is