Otto Julius Zobel (1887–1970) was a design engineer who worked for the American Telephone & Telegraph Company (AT&T) in the early part of the 20th century. Zobel's work on filter design was revolutionary and led, in conjunction with the work of John R. Carson, to significant commercial advances for AT&T in the field of frequency division multiplex (FDM) telephone transmissions. Although much of Zobel's work has been superseded by more modern filter designs, it remains the basis of filter theory and his papers are still referenced today. Zobel invented the m-derived filter and the constant-resistance filter, which remains in use. Zobel and Carson helped to establish the nature of noise in electric circuits, concluding that—contrary to mainstream belief—it is not even theoretically possible to filter out noise entirely and that noise will always be a limiting factor in what it is possible to transmit. Thus, they anticipated the later work of Claude Shannon, who showed how the theoretical information rate of a channel is related to the noise of the channel. (more...)

Recently featured: Nebula Science Fiction – Australian Cattle Dog – Warkworth Castle

• Intense Tropical Cyclone Funso stalls offshore central Mozambique, killing 15 people at sea and at least 14 others from inland flooding.
• The European Union imposes an embargo on future oil contracts with Iran.
• British novelist Salman Rushdie (pictured) cancels an appearance at the Jaipur Literature Festival in India, and four other writers leave the city after reading excerpts from The Satanic Verses, which is banned in the country.
• In a binding referendum, Croatian voters approve the country's proposed accession to the European Union.
• Boko Haram claims responsibility for a series of attacks in northern Nigeria that killed 185 people, two weeks after a similar set of assaults.