Antimicrobial stewardship programs typically use days of therapy to assess antimicrobial use. However, this metric does not account for the antimicrobial spectrum of activity. We applied an antibiotic spectrum index to a population of very-low-birth-weight infants to assess its utility to evaluate the impact of antimicrobial stewardship interventions.

We investigate irradiation-driven mass transfer in cataclysmic variables in the presence of shielding of the radiation by an accretion disk. We have shown that the shielding can cause a temporal drop of 3–5 magnitudes in the brightness of systems with orbital periods shorter than about 4 hr. This provides a possible explanation for the brightness variations in the VY Scl stars.

The history of astronomy has provided variable sources of unexpected kinds—from novae recorded in oriental archives, rapid radio, optical and high-energy changes in white dwarfs, neutron star and black hole binaries, to recent discoveries with satellites. A brief overview is given, as a prelude to a conference that anticipates a tidal wave of observations and discoveries to be made at all wavelengths during the next five to ten years.

Results of a high-speed photometric study of dwarf novæ in the Catalina Real-time Transient Survey are given. A population of faint dwarf novæ near the orbital period minimum is detected. At the shortest periods there is a correlation between orbital period and outburst interval.

The Business Meeting of Commission 41 was held in Sessions 2 on 5 August 2009, with Acting President Clive Ruggles (UK) in the Chair. He called for a moment of silence for those members who had passed away in the last triennium, including Prof. Xi Zezong (b. 1927, d. 2008 Dec 27) and Prof. Chen Meidong (b. 1936, d. 2008 Dec 30).

Commission 41 of the International Astronomical Union deals with all aspects of astronomical history and heritage from ancient sky knowledge to developments in modern astronomy that have occurred within living memory. It encourages and supports research in the history of astronomy and related fields such as archaeoastronomy and is also concerned with the identification, documentation and preservation of vital aspects of our astronomical heritage such as sites, artifacts, instruments and archives. Commission 41 is one of the largest Commissions in the Union, and is a member of Division XII on Union-Wide Activities.

We have developed a three-dimensional (3D) circuit integration technology that exploits the advantages of silicon-on-insulator (SOI) technology to enable wafer-level stacking and micrometer-scale electrical interconnection of fully fabricated circuit wafers. This paper describes the 3D technology and discusses some of the advanced focal plane arrays that have been built using it.

On Tuesday 22 August 2006 approximately 40 people attended the Commission 41 History of Astronomy Business Meeting at the IAU XXVI General Assembly in Prague. Commission president Alex Gurshtein opened the meeting, welcoming the commission members and calling for a moment of silence for those members who passed away in the last triennium. David DeVorkin was appointed recording secretary for the meeting, with Steven Dick as the scruitineer of the ballot. A moment of silence was then observed in the memory of members departed over the last triennium, including: Jerzy Dobrzycki (Poland), Robert Duncan (Australia), Mohammad Edalati (Iran), Philip Morrison (USA), John Perdix (Australia), Neil Porter (Ireland), Gibson Reaves (USA), Brian Robinson (Australia), and Raymond E. White (USA).

Following the Sydney General Assembly, the membership of C41 stood at 352, of whom, at the time of writing, three are known to have deceased. Since the formation of the Inter-Union Commission for the History of Astronomy (ICHA) prior to the Sydney General Assembly, C41/ICHA has subsequently acted, in effect, as an integrated Commission with a single OC. In this triennium the C41/ICHA OC made strong efforts to clarify and simplify the controversial issue of admitting non-IAU members to the ICHA. After prolonged and active consultation, the OC approved the document “Procedures for Admitting non-IAU members to the ICHA” and the OC Secretary Prof. Clive Ruggles officially presented this document to the history of astronomy community in C41/ICHA Newsletter no. 6. It is subject to ratification by the C41/ICHA Business Meeting in Prague in 2006.

Following our high speed photometric survey of faint cataclysmic variables, two CVs were recognised to be helium-transferring double degenerates; these are ES Cet (Рorb – 620.21144 s) and 2003aw (Psh= 2041.5 s). We have now observed ES Cet photometrically for over two years in order to follow the evolution of the orbital period. We oiler an alternative; explanation for the nature of V407 Vul (which was classified as an ultra-compact together with RX J0806 and ES Cet); this will take V407 Vul out of the AM CVn classification.