Factors related to children's caries: a structural equation modeling approach

published_or_final_versio

General theory of decoy-state quantum cryptography with source errors

The existing theory of decoy-state quantum cryptography assumes the exact control of each states from Alice's source. Such exact control is impossible in practice. We develop the theory of decoy-state method so that it is unconditionally secure even there are state errors of sources, if the range of a few parameters in the states are known. This theory simplifies the practical implementation of the decoy-state quantum key distribution because the unconditional security can be achieved with a slightly shortened final key, even though the small errors of pulses are not corrected.Comment: Our results can be used securely for any source of diagonal states, including the Plug-&-Play protocol with whatever error pattern, if we know the ranges of errors of a few parameter

Effects of ac-field amplitude on the dielectric susceptibility of relaxors

The thermally activated flips of the local spontaneous polarization in relaxors were simulated to investigate the effects of the applied-ac-field amplitude on the dielectric susceptibility. It was observed that the susceptibility increases with increasing the amplitude at low temperatures. At high temperatures, the susceptibility experiences a plateau and then drops. The maximum in the temperature dependence of susceptibility shifts to lower temperatures when the amplitude increases. A similarity was found between the effects of the amplitude and frequency on the susceptibility.Comment: 8 pages, 7 figures, Phys. Rev. B (in July 1st

A Close Binary Star Resolved from Occultation by 87 Sylvia

The star BD+29 1748 was resolved to be a close binary from its occultation by the asteroid 87 Sylvia on 2006 December 18 UT. Four telescopes were used to observe this event at two sites separated by some 80 km apart. Two flux drops were observed at one site, whereas only one flux drop was detected at the other. From the long-term variation of Sylvia, we inferred the probable shape of the shadow during the occultation, and this in turn constrains the binary parameters: the two components of BD+29 1748 have a projected separation of 0.097" to 0.110" on the sky with a position angle 104 deg to 107 deg. The asteroid was clearly resolved with a size scale ranging from 130 to 290 km, as projected onto the occultation direction. No occultation was detected for either of the two known moonlets of 87 Sylvia.Comment: 12 pages, 4 figures, 2 tables; submitted to the PAS

Magneto-optical visualization of vortices penetration into Ba(Fe1.8Co0.2)As2

Vortices penetration into oxygen-free superconducting compounds FeAs-122 system is of interest in understanding superconductivity. This work studies the vortices motion in Ba(Fe1.8Co0.2)As2 single crystal by means of magneto-optical imaging technique in zero field cooled and field cooled conditions. The captured magneto-optical images and corresponding flux profiles show that, at zero field cooled condition, vortices penetrate into the crystal from the edges as external magnetic field increases. A vortices-free region is observed at the center of sample as applied field is less than full penetration field. In field cooled condition, the introduced vortices leave the sample at the edges as field decreases and polarization of the vortices at the edges are opposite as decreasing field approaches to zero. The pinning strength decreases with increasing temperature. The observed vortex behavior is very similar to that in high Tc superconducting materials with strong pinning strength

Search for the decay J/ψ→γ+invisibleJ/\psi\to\gamma + \rm {invisible}

We search for $J/\psi$ radiative decays into a weakly interacting neutral particle, namely an invisible particle, using the $J/\psi$ produced through the process $\psi(3686)\to\pi^+\pi^-J/\psi$ in a data sample of $(448.1\pm2.9)\times 10^6$ $\psi(3686)$ decays collected by the BESIII detector at BEPCII. No significant signal is observed. Using a modified frequentist method, upper limits on the branching fractions are set under different assumptions of invisible particle masses up to 1.2 $\mathrm{\ Ge\kern -0.1em V}/c^2$. The upper limit corresponding to an invisible particle with zero mass is 7.0$\times 10^{-7}$ at the 90\% confidence level

On the Optimum Long Baseline for the Next Generation Neutrino Oscillation Experiments

For high energy long baseline neutrino oscillation experiments, we propose a Figure of Merit criterion to compare the statistical quality of experiments at various oscillation distances under the condition of identical detectors and a given neutrino beam. We take into account all possible experimental errors under general consideration. In this way the Figure of Merit is closely related to the usual statistical criterion of number of sigmas. We use a realistic neutrino beam for an entry level neutrino factory and a possible superbeam from a meson source and a 100 kt detector for the calculation. We considered in detail four oscillation distances, 300 km, 700 km, 2100 km and 3000 km, in the neutrino energy range of 0.5-20 GeV for a 20 GeV entry level neutrino factory and a 50 GeV superbeam. We found that the very long baselines of 2100 km and 3000 km are preferred for the neutrino factory according to the figure of merit criterion. Our results also show that, for a neutrino factory, lower primary muon energies such as 20 GeV are preferred rather than higher ones such as 30 or 50 GeV. For the superbeam, the combination of a long baseline such as 300 km and a very long baseline like 2100 km will form a complete measurement of the oscillation parameters besides the CP phase. To measure the CP phase in a superbeam, a larger detector (a factor 3 beyond what is considered in this article) and/or a higher intensity beam will be needed to put some significant constraints on the size of the CP angle.Comment: 21 LaTeX pages, 13 PS figures, typos corrected, references adde

Modeling realistic Earth matter density for CP violation in neutrino oscillation

We examine the effect of a more realistic Earth matter density model which takes into account of the local density variations along the baseline of a possi ble 2100 km very long baseline neutrino oscillation experiment. Its influence to the measurement of CP violation is investigated and a comparison with the commonly used global density models made. Significant differences are found in the comparison of the results of the different density models.Comment: 16 pages, 8 figure

Mesoscale modeling and simulation of microstructure evolution during dynamic recrystallization of a Ni-based superalloy

Microstructural evolution and plastic flow characteristics of a Ni-based superalloy were investigated using a simulative model that couples the basic metallurgical principle of dynamic recrystallization (DRX) with the twodimensional (2D) cellular automaton (CA). Variation of dislocation density with local strain of deformation is considered for accurate determination of the microstructural evolution during DRX. The grain topography, the grain size and the recrystallized fraction can be well predicted by using the developed CA model, which enables to the establishment of the relationship between the flow stress, dislocation density, recrystallized fraction volume, recrystallized grain size and the thermomechanical parameters