Stephen Levy

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BABAR, the detector for the SLAC PEP-II asymmetric e þ e À B Factory operating at the Uð4SÞ resonance, was designed to allow comprehensive studies of CP-violation in B-meson decays. Charged particle tracks are measured in a multi-layer silicon vertex tracker surrounded by a cylindrical wire drift chamber. Electromagnetic showers from electrons and photons(More)
The BaBar Silicon Vertex Tracker is a five layers, double sided AC-coupled silicon microstrip detector operating on the PEP-II storage ring at the Stanford Linear Accelerator Center. The performance of the SVT after 4 years of running is described. Results from radiation hardness tests are presented and the implications of the absorbed radiation dose on the(More)
We present a measurement of the time-dependent CP-violating (CPV) asymmetries in B0-->K(0)(S)pi(0) decays based on 124x10(6) Upsilon(4S)-->BB decays collected with the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC. In a sample containing 122+/-16 signal decays, we obtain the magnitudes of the direct CPV asymmetry(More)
There was more than athletic talent being pressed to peak performance at the 1984 Olympic Games in Los Angeles. Behind the scenes, a multilingual Olympic Message System ran round-the-clock keeping more than 10,000 athletes and officials in contact with families and friends, both far and near.
Rendezvous is a conference call solution that leverages Voice over IP, enterprise calendaring, instant messaging, and rich client functionality to enhance the user experience and effectiveness of distributed meetings. We describe the service, and two of its user experience innovations -- the conference call proxy and iHelp -- which function as digital(More)
<b>Two applications reveal the key challenges in makingcontext-aware computing a reality.</b><br>As mobile computing devices and a variety of sensors becomeubiquitous, new resources for applications and services - oftencollectively referred to under the rubric of context-awarecomputing - are becoming available to designers and developers. Inthis article, we(More)
We present an updated measurement of time-dependent CP-violating asymmetries in neutral B decays with the BABAR detector at the PEP-II asymmetric B Factory at SLAC. This result uses an additional sample of Upsilon(4S) decays collected in 2001, bringing the data available to 32 x 10(6) BB macro pairs. We select events in which one neutral B meson is fully(More)
IBM Enhanced Audio Conferencing (IEAC) is a VoIP-based audio conferencing system that, like several other systems, provides a visualization showing who is present and their states (e.g., speaking, muted). This paper presents the first study of the use of such a system. Drawing on log files collected over six weeks of use by over 1300 corporate employees,(More)
We experimentally investigated the equilibrium conformation and dynamics of single DNA molecules in slitlike nanochannels. We measured the in-plane radius of gyration (R)), diffusivity (D), and longest relaxation time (τ) of λ-DNA (48.5 kbp) as functions of the slit height using fluorescence microscopy. Our results show that the in-plane radius of gyration(More)