Oil price shocks, road transport pollution emissions and residents' health losses in China

China's rapid economic growth resulted in serious air pollution, which caused substantial losses to economic development and residents' health. In particular, the road transport sector has been blamed to be one of the major emitters. During the past decades, fluctuation in the international oil prices has imposed significant impacts on the China's road transport sector. Therefore, we propose an assumption that China's provincial economies are independent "economic entities". Based on this assumption, we investigate the China's road transport fuel (i.e., gasoline and diesel) demand system by using the panel data of all 31 Chinese provinces except Hong Kong, Macau and Taiwan. To connect the fuel demand system and the air pollution emissions, we propose the concept of pollution emissions elasticities to estimate the air pollution emissions from the road transport sector, and residents' health losses by a simplified approach consisting of air pollution concentrations and health loss assessment models under different scenarios based on real-world oil price fluctuations. Our framework, to the best of our knowledge, is the first attempt to address the transmission mechanism between the fuel demand system in road transport sector and residents' health losses in the transitional China

Large-scale stable interacting dark energy model: Cosmological perturbations and observational constraints

Dark energy might interact with cold dark matter in a direct, nongravitational way. However, the usual interacting dark energy models (with constant $w$) suffer from some catastrophic difficulties. For example, the $Q\propto\rho_{\rm c}$ model leads to an early-time large-scale instability, and the $Q\propto\rho_{\rm de}$ model gives rise to the future unphysical result for cold dark matter density (in the case of a positive coupling). In order to overcome these fatal flaws, we propose in this paper an interacting dark energy model (with constant $w$) in which the interaction term is carefully designed to realize that $Q\propto\rho_{\rm de}$ at the early times and $Q\propto\rho_{\rm c}$ in the future, simultaneously solving the early-time superhorizon instability and future unphysical $\rho_{\rm c}$ problems. The concrete form of the interaction term in this model is $Q=3\beta H \frac{\rho_{\rm{de}}\rho_{\rm{c}}}{\rho_{\rm{de}}+\rho_{\rm{c}}}$, where $\beta$ is the dimensionless coupling constant. We show that this model is actually equivalent to the decomposed new generalized Chaplygin gas (NGCG) model, with the relation $\beta=-\alpha w$. We calculate the cosmological perturbations in this model in a gauge-invariant way and show that the cosmological perturbations are stable during the whole expansion history provided that $\beta>0$. Furthermore, we use the Planck data in conjunction with other astrophysical data to place stringent constraints on this model (with eight parameters), and we find that indeed $\beta>0$ is supported by the joint constraint at more than 1$\sigma$ level. The excellent theoretical features and the support from observations all indicate that the decomposed NGCG model deserves more attention and further investigation.Comment: 13 pages, 3 figures; V2: appendix B (including a new figure) added; version accepted by Physical Review D; V3: matching the publication versio

(2+1)(2+1)-dimensional regular black holes with nonlinear electrodynamics sources

On the basis of two requirements: the avoidance of the curvature singularity and the Maxwell theory as the weak field limit of the nonlinear electrodynamics, we find two restricted conditions on the metric function of $(2+1)$-dimensional regular black hole in general relativity coupled with nonlinear electrodynamics sources. By the use of the two conditions, we obtain a general approach to construct $(2+1)$-dimensional regular black holes. In this manner, we construct four $(2+1)$-dimensional regular black holes as examples. We also study the thermodynamic properties of the regular black holes and verify the first law of black hole thermodynamics.Comment: 13 pages, 4 figures. in press in PL

Disorder-Driven Superconductor-Insulator Transition in d-Wave Superconducting Ultrathin Films

We study the superconductor-insulator transition (SIT) in $d$-wave superconducting ultrathin films. By means of the kernel polynomial method, the Bogoliubov-de Gennes equations are solved for square lattices with up to $360\times 360$ unit cells self-consistently, making it possible to observe fully the nanoscale spatial fluctuations of the superconducting order parameters and discriminate accurately the localized quasiparticle states from the extended ones by the lattice-size scaling of the generalized inverse participation ratio. It is shown that Anderson localization can not entirely inhibit the occurrence of the local superconductivity in strongly-disordered $d$-wave superconductors. Separated by an insulating 'sea' completely, a few isolated superconducting 'islands' with significant enhancement of the local superconducting order parameters can survive across the SIT. The disorder-driven SIT, therefore, is a transition from a $d$-wave superconductor to a Bose insulator which consists of localized Cooper pairs. Unlike an $s$-wave superconductor which presents a robust single-particle gap across the SIT, the optical conductivity of a $d$-wave superconductor reveals a gapless insulating phase, where the SIT can be detected by observing the disappearance of the Drude weight with the increasing disorder.Comment: 8 pages, 6 figure

Evacuation simulation considering action of the guard in an artificial attack

To investigate the evacuation behaviors of pedestrians considering action of the guard and develop an effective evacuation strategy in the artificial attack, an extended floor field model was proposed. In this model, the assault on pedestrians, the death of pedestrians and the capture of the guard were involved simultaneously. An alternative evacuation strategy which can largely reduce the number of death was developed and effects of several key parameters such as the deterrence radius and capture distance on evacuation dynamics were studied. Results show that congestion near the exit has dual effects. More specially, the guard could catch all attackers in a short time because the attackers would have more concentrated distribution, but more casualties would happen because pedestrians are hard to escape the attack due to congestion. In contrast, when pedestrians have more preference of approaching the guard, although the guard would take more time to capture the attackers result from the dispersion of attackers, the death toll would decrease. One of the reason is the dispersal of the crowd and the decrease in congestion would be beneficial for escape. Another is the attackers would be killed before launching the attack to the people those are around the guard, in other words, the guard would protect a large number of pedestrians from being killed. Moreover, increasing capture distance of the guard can effectively reduce the casualties and the catch time. As the deterrence radius reflecting the tendency of escaping from the guard for attackers rises, it would become more difficult for the guard to catch the attackers and more casualties are caused. However, when the deterrence radius reaches a certain level, the number of deaths would be reduced because the attackers would prefer to stay as far away as possible from instead of the position where they could attack more people.Comment: 20 pages, 12 figures and 1 tabl

Derivative coupling of inflaton to R(3)R^{(3)}

We study the inflation scenario with the non-minimally derivative coupling $XR^{(3)}$, where $X=\nabla_\mu\phi \nabla^\mu\phi$, $\phi$ is the inflaton and $R^{(3)}$ is the 3-dimensional intrinsic Ricci scalar on the spacelike hypersurface, and analytically calculate the corrections of $XR^{(3)}$ on the power spectra of primordial perturbations. It is found that for the $\phi^2$ inflation model, the corresponding predictions can be driven to the best-fit region of the $n_s$-$r$ diagram.Comment: 14 pages, 3 figure

On some new global existence result of 3D Magnetohydrodynamic equations

This paper is devoted to the incompressible Magenetohydrodynamic equations in $\R^3$. We prove that if the difference between the magnetic field and the velocity is small initially then it will remain forever, thus results in global strong solution without smallness restriction on the size of initial velocity or magnetic field. In other words, magnetic field can indeed regularize the Navier-Stokes equations, due to cancelation.Comment: 11 page

Voltage induced by Coriolis force: a new sensing scheme for rotation velocity

We study the motion of the charged particles between a pair of conductor plates in the non-inertial reference frame. It is found that there exists a stable voltage between the two conductor plates, which is proportional to the rotation velocity of the non-inertial system. This effect is similar to the Hall effect as the result of the Lorenz force. As an application, we propose a rotation velocity measurement scheme based on this Coriolis force -induced effect.Comment: 3 pages, 3 figures, comments are welcom

Activity Analyses for Solar-Type Stars Observed With Kepler. I. Proxies of Magnetic Activity

Light curves of solar-type stars often show gradual fluctuations due to rotational modulation by magnetic features (starspots and faculae) on stellar surfaces. Two quantitative measures of modulated light curves are employed as the proxies of magnetic activity for solar-type stars observed with Kepler telescope. The first is named autocorrelation index $i_{AC}$, which describes the degree of periodicity of the light curve, the second is the effective fluctuation range of the light curve $R_{eff}$, which reflects the depth of rotational modulation. The two measures are complementary and depict different aspects of magnetic activities on solar-type stars. By using the two proxies $i_{AC}$ and $R_{eff}$, we analyzed activity properties of two carefully selected solar-type stars observed with Kepler (Kepler ID: 9766237 and 10864581), which have distinct rotational periods (14.7 vs. 6.0 days). We also applied the two measures to the Sun for a comparative study. The result shows that both the measures can reveal cyclic activity variations (referred to as $i_{AC}$-cycle and $R_{eff}$-cycle) on the two Kepler stars and the Sun. For the Kepler star with the faster rotation rate, $i_{AC}$-cycle and $R_{eff}$-cycle are in the same phase, while for the Sun (slower rotator), they are in the opposite phase. By comparing the solar light curve with simultaneous photospheric magnetograms, it is identified that the magnetic feature that causes the periodic light curve during solar minima is the faculae of the enhanced network region, which can also be a candidate of magnetic features that dominate the periodic light curves on the two Kepler stars.Comment: 46 pages, 14 figures, 6 table

MUSE: Modularizing Unsupervised Sense Embeddings

This paper proposes to address the word sense ambiguity issue in an unsupervised manner, where word sense representations are learned along a word sense selection mechanism given contexts. Prior work focused on designing a single model to deliver both mechanisms, and thus suffered from either coarse-grained representation learning or inefficient sense selection. The proposed modular approach, MUSE, implements flexible modules to optimize distinct mechanisms, achieving the first purely sense-level representation learning system with linear-time sense selection. We leverage reinforcement learning to enable joint training on the proposed modules, and introduce various exploration techniques on sense selection for better robustness. The experiments on benchmark data show that the proposed approach achieves the state-of-the-art performance on synonym selection as well as on contextual word similarities in terms of MaxSimC