We present Epoch-Greedy, an algorithm for contextual multi-armed bandits (also known as bandits with side information). Epoch-Greedy has the following properties: 1. No knowledge of a time horizon T is necessary. 2. The regret incurred by Epoch-Greedy is controlled by a sample complexity bound for a hypothesis class. 3. The regret scales asO(T S) or better (sometimes, much better). Here S is th...

Recent advances in technology have enabled astronomers to observe fainter, and more distant, galaxies and to study the processes of galaxy formation and evolution. Recent observations suggest that the bulk of the stars in the universe formed between z 5 3 (;1 3 109 years after the big bang) and the present. The star formation rate appears to have peaked at z; 1–2 (; 2–43 109 years after the big...

OBJECTIVE To describe trends in mortality of open cardiac surgery in children in Bristol and England since 1991. DESIGN Retrospective analysis of hospital episode statistics data. SETTING All open cardiac surgery of children in England. POPULATION Patients younger than 16 undergoing open cardiac surgical procedures in England between April 1991 and March 2002. Three time periods were defi...

We use a semi-analytic model of galaxy formation in hierarchical clustering theories to interpret recent data on galaxy formation and evolution, focussing primarily on the recently discovered population of Lyman-break galaxies at z ≃ 3. For a variety of cold dark matter (CDM) cosmologies we construct mock galaxy catalogues subject to identical selection criteria to those applied to the real dat...

The recent observations of cross temperature-polarization power spectra of the Cosmic Microwave Background (CMB) made by the WMAP satellite are in better agreement with a high value of the Thomson scattering optical depth τ ≈ 0.17. This value is close to τ = 0.3, which is taken as the upper limit in the parameter extraction analysis made by the WMAP team. However, models with τ ∼ 0.3 provide a ...

Los Guindos scheelite (±Zn, Bi, Sn, Ag) skarn presents mineral assemblages and a chemistry similar to other worldwide strongly reduced W deposits. Its nature is defined based on the predominance of subcalcic garnets, Mo-free absence magnetite. Both prograde retrograde stages are evident at skarn. The characterized by three zones: A zone I garnet + helvine (Gr57Sps24Ad19Alm8 - Sps50Alm24Gr22Ad3;...

New evidence gained by the study of Foraminifera from Khuzestan province in southwest Iran reveals that the basal limit of the genus Heterostegina is not restricted to the Eocene epoch. By introducing a new species of this genus (H. rezvaninejadi), this study shows that the early appearance of this genus should be lowered down further still, at least, into the Middle Paleocene.