An analogue of Ryser's Theorem for partial Sudoku squares

In 1956 Ryser gave a necessary and sufficient condition for a partial latin rectangle to be completable to a latin square. In 1990 Hilton and Johnson showed that Ryser's condition could be reformulated in terms of Hall's Condition for partial latin squares. Thus Ryser's Theorem can be interpreted as saying that any partial latin rectangle $R$ can be completed if and only if $R$ satisfies Hall's Condition for partial latin squares. We define Hall's Condition for partial Sudoku squares and show that Hall's Condition for partial Sudoku squares gives a criterion for the completion of partial Sudoku rectangles that is both necessary and sufficient. In the particular case where $n=pq$, $p|r$, $q|s$, the result is especially simple, as we show that any $r \times s$ partial $(p,q)$-Sudoku rectangle can be completed (no further condition being necessary).Comment: 19 pages, 10 figure

The effect of operations on the ground noise footprints associated with a large multibladed, nonbanging helicopter

In order to expand the data base of helicopter external noise characteristics, a flyover noise measurement program was conducted utilizing the NASA Civil Helicopter Research Aircraft. The remotely operated multiple array acoustics range (ROMAAR) and a 2560-m linear microphone array were utilized for the purpose of documenting the noise characteristics of the test helicopter during flyby and landing operations. By utilizing both ROMAAR concept and the linear array, the data necessary to plot the ground noise footprints and noise radiation patterns were obtained. Examples of the measured noise signature of the test helicopter, the ground noise footprint or contours, and the directivity patterns measured during level flyby and landing operations of a large, multibladed, nonbanging helicopter, the CH-53, are presented

Noise measurement evaluations of various takeoff-climbout profiles of a four-engine turbojet transport airplane

Noise measurement evaluations of various takeoff-climbout profiles of four engine turbojet transport airplan

M dwarf stars in the light of (future) exoplanet searches

We present a brief overview of a splinter session on M dwarf stars as planet hosts that was organized as part of the Cool Stars 17 conference. The session was devoted to reviewing our current knowledge of M dwarf stars and exoplanets in order to prepare for current and future exoplanet searches focusing in low mass stars. We review the observational and theoretical challenges to characterize M dwarf stars and the importance of accurate fundamental parameters for the proper characterization of their exoplanets and our understanding on planet formation.Comment: 4 pages, 1 figure. Summary of the splinter session "M dwarf stars in the light of (future) exoplanet searches" held at the 17th Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun, June 28th 2012, Barcelona, Spain. Submitted for publication in Astronomische Nachrichten - Astronomical Notes (AN) 334, Issue 1-2, Eds Klaus Strassmeier and Mercedes L\'opez-Morale

Strongly quadrature-dependent noise in superconducting micro-resonators measured at the vacuum-noise limit

We measure frequency- and dissipation-quadrature noise in superconducting lithographed microwave resonators with sensitivity near the vacuum noise level using a Josephson parametric amplifier. At an excitation power of 100~nW, these resonators show significant frequency noise caused by two-level systems. No excess dissipation-quadrature noise (above the vacuum noise) is observed to our measurement sensitivity. These measurements demonstrate that the excess dissipation-quadrature noise is negligible compared to vacuum fluctuations, at typical readout powers used in micro-resonator applications. Our results have important implications for resonant readout of various devices such as detectors, qubits and nano-mechanical oscillators.Comment: 13 pages, 4 figure