The kHz QPOs as a probe of the X-ray color-color diagram and accretion-disk structure for the atoll source 4U 1728-34

We have taken the kHz QPOs as a tool to probe the correlation between the tracks of X-ray color-color diagram (CCD) and magnetosphere-disk positions for the atoll source 4U 1728-34, based on the assumptions that the upper kHz QPO is ascribed to the Keplerian orbital motion and the neutron star (NS) magnetosphere is defined by the dipole magnetic field. We find that from the island to the banana state, the inner accretion disk gradually approaches the NS surface with the radius decreasing from r ~33.0km to ~15.9 km, corresponding to the magnetic field from B(r) ~4.8*10^6 G to ~4.3*10^7 G. In addition, we note the characteristics of some particular radii of magnetosphere-disk -r are: firstly, the whole atoll shape of the CCD links the disk radius range of ~15.9 - 33.0 km, which is just located inside the corotation radius of 4U 1728-34 -r_co ( ~34.4 km), implying that the CCD shape is involved in the NS spin-up state. Secondly, the island and banana states of CCD correspond to the two particular boundaries: (I)-near the corotation radius at r ~27.2 - 33.0 km, where the source lies in the island state; (II)-near the NS surface at r ~15.9 - 22.3 km, where the source lies in both the island and banana states. Thirdly, the vertex of the atoll shape in CCD, where the radiation transition from the hard to soft photons occurs, is found to be near the NS surface at r ~16.4 km. The above results suggest that both the magnetic field and accretion environment are related to the CCD structure of atoll track, where the corotation radius and NS hard surface play the significant roles in the radiation distribution of atoll source.Comment: 6 pages, 3 figures, 1 table, accepted by Astronomy & Astrophysic

Learning user-specific latent influence and susceptibility from information cascades

Predicting cascade dynamics has important implications for understanding information propagation and launching viral marketing. Previous works mainly adopt a pair-wise manner, modeling the propagation probability between pairs of users using n^2 independent parameters for n users. Consequently, these models suffer from severe overfitting problem, specially for pairs of users without direct interactions, limiting their prediction accuracy. Here we propose to model the cascade dynamics by learning two low-dimensional user-specific vectors from observed cascades, capturing their influence and susceptibility respectively. This model requires much less parameters and thus could combat overfitting problem. Moreover, this model could naturally model context-dependent factors like cumulative effect in information propagation. Extensive experiments on synthetic dataset and a large-scale microblogging dataset demonstrate that this model outperforms the existing pair-wise models at predicting cascade dynamics, cascade size, and "who will be retweeted".Comment: from The 29th AAAI Conference on Artificial Intelligence (AAAI-2015

Observation of recoil-induced resonances and electromagnetically induced absorption of cold atoms in diffuse light

In this paper we report an experiment on the observation of the recoil-induced resonances (RIR) and electromagnetically induced absorption (EIA) of cold Rb87 atoms in diffuse light. The pump light of the RIR and the EIA comes from the diffuse light in an integrating sphere, which also serves the cooling light. The probe light beam is a weak laser split from the cooling laser in order to keep the cooling and probe lasers correlated. We measured the RIR and the EIA signal varying with the detuning of the diffuse laser light, and also measured the temperature of the cold atoms at the different detunings. The mechanism of RIR and EIA in the configuration with diffuse-light pumping and laser probing is discussed, and the difference of nonlinear spectra of cold atoms between in diffuse-light cooling system and in optical molasses as well as in a magneto-optical trap (MOT) are studied.Comment: 9 pages, 6 figure

Looking at both sides of leader and follower political skill on work outcomes: the mediating role of job satisfaction

Based on existing research addressing political skill and social net- works, this study explores the congruence effects of the political skills of leaders and followers on workers’job satisfaction, and the resulting effect on followers’life satisfaction and affective commitment. Using cross-level polynomial regressions and 3D response surface analysis on 305 leader and follower dyads, the results supported the congruence and effect hypothesis. Furthermore, this study has also discovered incongruence effects: when leaders’ political skills are higher than those of their followers, the degree of decline in job satisfaction, life satisfaction, and affective commitment is greater than the size of difference between the political skills of leaders and followers. This study also reveals the importance of leaders and followers possessing political skills, especially considering its important effect on work attitude and performance