نتایج جستجو برای: epoch

تعداد نتایج: 10565  

Journal: :Geological Magazine 1867

Journal: :Archives of pediatrics & adolescent medicine 2009
Pamela K Donohue Renee D Boss Jennifer Shepard Ernest Graham Marilee C Allen

OBJECTIVE To investigate prenatal management and outcome of infants born at the border of viability during 2 periods, 2001 to 2003 (late epoch) and 1993 to 1995 (early epoch). DESIGN Cohort study. SETTING Single academic, high-risk perinatal referral center. PARTICIPANTS All 160 women admitted to labor and delivery with a live fetus who delivered at an estimated gestational age of 220/7 w...

Journal: :Азия и Африка сегодня 2018

2007
John Langford Tong Zhang

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...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 1997
D N Spergel S J Lilly C Steidel

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...

Journal: :BMJ 2004
Paul Aylin Alex Bottle Brian Jarman Paul Elliott

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...

1998
S. Cole C. S. Frenk

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...

2005
Roy Choudhury P. Serra A. Ferrara

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 ...

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.

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