New Results on Bs Mixing from LEP

The phenomenology of B_s^0 oscillations is reviewed along with the experimental strategy for observing them. Results of studies from ALEPH, DELPHI, and OPAL experiments are summarized with an emphasis on recent new results from ALEPH.Comment: 9 pages, 7 figures, submitted to Proceedings of Flavour Physics and CP Violation 200

Chip level simulation of fault tolerant computers

Chip level modeling techniques, functional fault simulation, simulation software development, a more efficient, high level version of GSP, and a parallel architecture for functional simulation are discussed

Traveling wave oscillations in the optical region: a theoretical examination

The interaction of an electron beam with the optical field of a periodically perturbed dielectric thin-film waveguide is considered. When the electron velocity is nearly equal to that of one of the spatial harmonics of the field, a coherent exchange of energy can take place. This interaction, which can lead in principle to a voltage-tunable optical oscillation, is examined in the light of presently available thin-film techniques. An estimate of the oscillation threshold is made

Is FIRST J102347.6+003841 Really a Cataclysmic Binary?

The radio source FIRST J102347.6+003841 was presented as the first radio-selected cataclysmic. In the discovery paper, Bond et al. (2002) show a spectrum consistent with a magnetic AM Her-type system and a light curve with rapid, irregular flickering. In contrast, Woudt, Warner, and Pretorius (2004) found a smoothly-varying light curve with a period near 4.75 h and one minimum per orbit, indicating a dramatic change. We present time-resolved spectra showing a superficially normal, mid-G type photosphere, with no detectable emission lines. The absorption-line radial velocity varies sinusoidally, with semi-amplitude 268 +- 4 km/s, on the orbital period, which is refined to 0.198094(2) d. At this orbital period the secondary's spectral type is atypically early, suggesting an unusual evolutionary history. We also obtained BVI photometry around the orbit. The light curve resembles that given by Woudt et al., and the color modulation is consistent with a heating effect. A simple illumination model matches the observations strikingly well with a Roche-lobe filling secondary near 5650 kelvin being illuminated by a primary giving out around 2 solar luminosities. The modest amplitude of the observed modulation constrains the orbital inclination to be less than about 55 deg, unless the gravity darkening is artificially reduced. The resulting primary star mass is above the Chandrasekhar limit (assuming conventional gravity darkening). We examine the possibility that the compact object in this system is not a white dwarf, in which case this is not actually a cataclysmic variable. On close examination, FIRST J102347.6+003841 defies easy classification.Comment: 24 pages, 5 postscript and two JPG figures; Astronomical Journal, accepte

Operating injection lasers by fast square current pulses of variable amplitude

A simple solid state circuit was used to drive GaAs injection lasers by fast (∼100 nsec) square pulses of variable amplitude (0–25 A). The amplitudes of the current pulses and the corresponding emitted light pulses were measured by a dual peak detector circuit. Using these circuits we were able to plot automatically the current vs light curve and determine the threshold current of the laser diodes

Fast, high current, high repetition rate pulse generator for injection lasers

The circuit described is capable of generating high‐current (2–50 A), fast‐rise‐time (10 nsec), square‐wave pulses into a 50‐Ω load. This circuit may be used for driving injection lasers at high repetition rates (up to 1.5 kHz) when connected to coaxial cables

Forecasting for Marketing

Research on forecasting is extensive and includes many studies that have tested alternative methods in order to determine which ones are most effective. We review this evidence in order to provide guidelines for forecasting for marketing. The coverage includes intentions, Delphi, role playing, conjoint analysis, judgmental bootstrapping, analogies, extrapolation, rule-based forecasting, expert systems, and econometric methods. We discuss research about which methods are most appropriate to forecast market size, actions of decision makers, market share, sales, and financial outcomes. In general, there is a need for statistical methods that incorporate the manager's domain knowledge. This includes rule-based forecasting, expert systems, and econometric methods. We describe how to choose a forecasting method and provide guidelines for the effective use of forecasts including such procedures as scenarios.forecasting, marketing

JointZone: users' view of an adaptive online learning resource for rheumatology

This paper describes an online learning resource for rheumatology that was designed for a wide constituency of users including primarily undergraduate medical students and health professionals. Although the online resources afford an informal learning environment, the site was pedagogically designed to comply with the general recommendations of the Standing Committee on Training and Education of EULAR (European League Against Rheumatism) for a rheumatology core curriculum. Any Internet user may freely browse the site content with optional registration providing access to adaptive features that personalize the user’s view, for example, providing a reading history and targeted support based on scores from completed case studies. The site has now been available since early 2003, and an online survey of site registrants indicates that well structured pedagogical materials that reflect a learners’ dominant ‘community of practice’ appear to be a successful aid to informal learning

Nano-Hertz Gravitational Waves Searches with Interferometric Pulsar Timing Experiments

We estimate the sensitivity to nano-Hertz gravitational waves of pulsar timing experiments in which two highly-stable millisecond pulsars are tracked simultaneously with two neighboring radio telescopes that are referenced to the same time-keeping subsystem (i.e. "the clock"). By taking the difference of the two time-of-arrival residual data streams we can exactly cancel the clock noise in the combined data set, thereby enhancing the sensitivity to gravitational waves. We estimate that, in the band ($10^{-9} - 10^{-8}$) Hz, this "interferometric" pulsar timing technique can potentially improve the sensitivity to gravitational radiation by almost two orders of magnitude over that of single-telescopes. Interferometric pulsar timing experiments could be performed with neighboring pairs of antennas of the forthcoming large arraying projects.Comment: Paper submitted to Phys. Rev. Letters. It is 9 pages long, and includes 2 figure

Exomoon Habitability and Tidal Evolution in Low-Mass Star Systems

Discoveries of extrasolar planets in the habitable zone (HZ) of their parent star lead to questions about the habitability of massive moons orbiting planets in the HZ. Around low-mass stars, the HZ is much closer to the star than for Sun-like stars. For a planet-moon binary in such a HZ, the proximity of the star forces a close orbit for the moon to remain gravitationally bound to the planet. Under these conditions the effects of tidal heating, distortion torques, and stellar perturbations become important considerations for exomoon habitability. Utilizing a model that considers both dynamical and tidal interactions simultaneously, we performed a computational investigation into exomoon evolution for systems in the HZ of low-mass stars ($\lesssim 0.6\ M_{\odot}$). We show that dwarf stars with masses $\lesssim 0.2\ M_{\odot}$ cannot host habitable exomoons within the stellar HZ due to extreme tidal heating in the moon. Perturbations from a central star may continue to have deleterious effects in the HZ up to $\approx 0.5\ M_{\odot}$, depending on the host planet's mass and its location in the HZ, amongst others. In addition to heating concerns, torques due to tidal and spin distortion can lead to the relatively rapid inward spiraling of a moon. Therefore, moons of giant planets in HZs around the most abundant type of star are unlikely to have habitable surfaces. In cases with lower intensity tidal heating the stellar perturbations may have a positive influence on exomoon habitability by promoting long-term heating and possibly extending the HZ for exomoons.Comment: accepted by MNRAS, 20 pages, 8 figures in main text (7 col, 1 b/w