A nonparametric analysis of consumer expenditure patterns suggests that Engel curves require quadratic terms in the logarithm of expenditure. While popular models of demand such as the Translog or the ...

Learn more about how Waterfall works, what projects the methodology is best suited for and how it compares with Agile, another project management method.

Nonlinear optics articles from across Nature Portfolio Nonlinear optics is the study of how intense light interacts with matter. The optical response of a material usually scales linearly with the ...

One part of understanding the difference between external reality and mental life involves the ability to differentiate what is seen from what is known. This research investigated the development of ...

Use BBC.com or the new BBC App to listen to BBC podcasts, Radio 4 and the World Service outside the UK. Find out how to listen to other BBC stations ...