’Eyes free’ in-car assistance: parent and child passenger collaboration during phone calls

This paper examines routine family car journeys, looking specifically at how passengers assist during a mobile telephone call while the drivers address the competing demands of handling the vehicle, interacting with various artefacts and controls in the cabin, and engage in co-located and remote conversations while navigating through busy city roads. Based on an analysis of video fragments, we see how drivers and child passengers form their conversations and requests around the call so as to be meaningful and paced to the demands, knowledge and abilities of their cooccupants, and how the conditions of the road and emergent traffic are oriented to and negotiated in the context of the social interaction that they exist alongside. The study provides implications for the design of car-based collaborative media and considers how hands- and eyesfree natural interfaces could be tailored to the complexity of activities in the car and on the road

Covariant spectator theory of np scattering: Phase shifts obtained from precision fits to data below 350 MeV

Using the covariant spectator theory (CST), we present two one boson exchange kernels that have been successfully adjusted to fit the 2007 world np data (containing 3788 data) below 350 MeV. One model (which we designate WJC-1) has 27 parameters and fits with a chi2/N = 1.06. The other model (designated WJC-2) has only 15 parameters and fits with a chi2/N = 1.12. Both of these models also reproduce the experimental triton binding energy without introducing additional irreducible three-nucleon forces. One result of this work is a new phase shift analysis, updated for all data until 2006, which is useful even if one does not work within the CST. In carrying out these fits we have reviewed the entire data base, adding new data not previously used in other high precision fits and restoring some data omitted in previous fits. A full discussion and evaluation of the 2007 data base is presented.Comment: 43 pages, 27 figures, and 13 table

The ground state energy of a massive scalar field in the background of a semi-transparent spherical shell

We calculate the zero point energy of a massive scalar field in the background of an infinitely thin spherical shell given by a potential of the delta function type. We use zeta functional regularization and express the regularized ground state energy in terms of the Jost function of the related scattering problem. Then we find the corresponding heat kernel coefficients and perform the renormalization, imposing the normalization condition that the ground state energy vanishes when the mass of the quantum field becomes large. Finally the ground state energy is calculated numerically. Corresponding plots are given for different values of the strength of the background potential, for both attractive and repulsive potentials.Comment: 15 pages, 5 figure

Observation of the March Maximum in the Daemon Flux from Neos in the Year 2005: New Efforts and New Effects

The experiments of 2005 aimed at detection of low-velocity (~10-15 km s-1) daemons falling on to the Earth's surface from Near-Earth, Almost Circular Heliocentric Orbits (NEACHOs) have corroborated once more the existence of the March maximum in their flux by raising its confidence level to 99.99%. In addition, these experiments permitted us to identify several FEU-167-1-type PM tubes, with a few times thicker inner Al coating, which appear to be capable to detect, without any scintillator, the crossing of negatively charged daemons. As a result, detection efficiency increases tens of times, thus raising the measured level of the March daemon flux to f > 0.5E-7 cm-2s-1.Comment: 14 page

Inverse Scattering and Acousto-Optic Imaging

We propose a tomographic method to reconstruct the optical properties of a highly-scattering medium from incoherent acousto-optic measurements. The method is based on the solution to an inverse problem for the diffusion equation and makes use of the principle of interior control of boundary measurements by an external wave field.Comment: 10 page

Phase transition in the globalization of trade

Globalization processes interweave economic structures at a worldwide scale, trade playing a central role as one of the elemental channels of interaction among countries. Despite the significance of such phenomena, measuring economic globalization still remains an open problem. More quantitative treatments could improve the understanding of globalization at the same time that help a formal basis for comparative economic history. In this letter, we investigate the time evolution of the statistical properties of bilateral trade imbalances between countries in the trade system. We measure their cumulative probability distribution at different moments in time to discover a sudden transition circa 1960 from a regime where the distribution was always represented by a steady characteristic function to a new state where the distribution dilates as time goes on. This suggests that the rule that was governing the statistical behavior of bilateral trade imbalances until the 60's abruptly changed to a new form persistent in the last decades. In the new regime, the figures for the different years collapse into a universal master curve when rescaled by the corresponding global gross domestic product value. This coupling points to an increased interdependence of world economies and its onset corresponds in time with the starting of the last globalization wave.Comment: Final versio

Coherent spin manipulation in an exchange-only qubit

Initialization, manipulation, and measurement of a three-spin qubit are demonstrated using a few-electron triple quantum dot, where all operations can be driven by tuning the nearest-neighbor exchange interaction. Multiplexed reflectometry, applied to two nearby charge sensors, allows for qubit readout. Decoherence is found to be consistent with predictions based on gate voltage noise with a uniform power spectrum. The theory of the exchange-only qubit is developed and it is shown that initialization of only two spins suffices for operation. Requirements for full multi-qubit control using only exchange and electrostatic interactions are outlined.Comment: related work at http://marcuslab.harvard.ed