A letter to the editor

The goal of this letter is to point out that the fastest way to weaken any society and its business model, including the IEEE and its reader-pays stance, is to lose your professional integrity

Hopf algebras up to homotopy and the Bockstein spectral sequence

Anick proved that every q-mild Hopf algebra up to homotopy is isomorphic to a primitively-generated chain Hopf algebra. We provide a new proof, that involves extensive use of the Bockstein spectral sequence.Comment: Published by Algebraic and Geometric Topology at http://www.maths.warwick.ac.uk/agt/AGTVol5/agt-5-7.abs.htm

The engineers that time forgot

You and I, dear reader of IEEE Microwave Magazine, are set to become more valuable day by day. Let me see if I can paint a picture of why

Electronics: A potted history and a glimpse of the future

Keynote Speech. New Zealand has a thriving electronics industry with a long history. The renowned Kiwi ingenuity fits in well with the creative, understanding-based aspects of electronics, a discipline that is both an art and a science. However, the face of electronics is changing with the passing decades

3D-printed Acoustic Directional Couplers

Acoustic Directional Couplers permit separation of forward and reverse sound pressure waves. This separation opens the way to traceable precision acoustic reflection measurements. In order to span the audio frequency range, multiple couplers will be required, as each operates over a frequency range of slightly more than one octave. To reach 20kHz or above requires vary small, mechanically precise construction. We achieve this by 3D printing techniques. We manufactured two otherwise-identical couplers, one made with a powder-type 3D printer with photopolymer support structure, the other made with an ABS-filament thermoplastic-type 3D printer. We compare the measured acoustic performance of these two couplers. The wavelength of sound at 20 kHz is comparable to that encountered at a microwave frequency of 18 GHz. We expect to be able to fabricate couplers that reach 55 kHz where the wavelength is 6 mm, corresponding to a frequency of 50 GHz in the electromagnetic spectrum

Twisting structures and strongly homotopy morphisms

In an application of the notion of twisting structures introduced by Hess and Lack, we define twisted composition products of symmetric sequences of chain complexes that are degreewise projective and finitely generated. Let Q be a cooperad and let BP be the bar construction on the operad P. To each morphism of cooperads g from Q to BP is associated a P-co-ring, K(g), which generalizes the two-sided Koszul and bar constructions. When the co-unit from K(g) to P is a quasi-isomorphism, we show that the Kleisli category for K(g) is isomorphic to the category of P-algebras and of their morphisms up to strong homotopy, and we give the classifying morphisms for both strict and homotopy P-algebras. Parametrized morphisms of (co)associative chain (co)algebras up to strong homotopy are also introduced and studied, and a general existence theorem is proved. In the appendix, we study the particular case of the two-sided Koszul resolution of the associative operad.Comment: 54 page

A Place to Call Home: What Immigrants Say Now About Life in America

Examines immigrants' views on opportunities in the United States, discrimination against immigrants, ties to their countries of origin, U.S. citizenship, and immigration policy. Analyzes variations from 2002 and by country of origin, religion, and age