If scientists had sacred objects, this would be one of them: a single, closely guarded 137-year-old cylinder of metal, housed in a vault outside of Paris. It is a prototype that precisely defines a ...

The world’s measurement system will be based on updated values for four fundamental constants of nature. A revised SI ( the International System of Units ) based fully on accurate values of these ...

This is a preview. Log in through your library . Journal Information The oldest mathematics journal in the Western Hemisphere in continuous publication, the American Journal of Mathematics ranks as ...

Charter schools, Teach For America, and the Knowledge Is Power Program may have their merits, but they are not whole-system reform. The latter is about improving every classroom, every school, and ...

Nick van Remortel demystifies natural unit systems — and advises what to do when you see a mass expressed in GeV. Several unit systems for describing the natural world exist. The International System ...

We have investigated the fundamental characteristics of unit injectors and pump-line-nozzle systems theoretically by a graphical analysis of characteristic lines. We have confirmed the higher ...