Evolution characteristics of the network core in the facebook

Statistical properties of the static networks have been extensively studied. However, online social networks are evolving dynamically, understanding the evolving characteristics of the core is one of major concerns in online social networks. In this paper, we empirically investigate the evolving characteristics of the Facebook core. Firstly, we separate the Facebook-link(FL) and Facebook-wall(FW) datasets into 28 snapshots in terms of timestamps. By employing the k-core decomposition method to identify the core of each snapshot, we find that the core sizes of the FL and FW networks approximately contain about 672 and 373 nodes regardless of the exponential growth of the network sizes. Secondly, we analyze evolving topological properties of the core, including the k-core value, assortative coefficient, clustering coefficient and the average shortest path length. Empirical results show that nodes in the core are getting more interconnected in the evolving process. Thirdly, we investigate the life span of nodes belonging to the core. More than 50% nodes stay in the core for more than one year, and 19% nodes always stay in the core from the first snapshot. Finally, we analyze the connections between the core and the whole network, and find that nodes belonging to the core prefer to connect nodes with high k-core values, rather than the high degrees ones. This work could provide new insights into the online social network analysis

Entanglement measurement based on two-particle interference

We propose a simple and realizable method using a two-particle interferometer for the experimental measurement of pairwise entanglement, assuming some prior knowledge about the quantum state. The basic idea is that the properties of the density matrix can be revealed by the single- and two-particle interference patterns. The scheme can easily be implemented with polarized entangled photons.Comment: 5 pages, 1 figur

Effects of Drying Methods on Physico-Chemical Properties and Antioxidant Activity of Shiitake Mushrooms (Lentinus Edodes)

The effects of different drying methods including natural air-drying (ND), hot air drying (HD), vacuum drying (VD), microwave drying (MD), infra-red drying (ID), and freeze drying (FD) on physico-chemical properties and antioxidant activities of shiitake mushroom were investigated in this paper. The results showed that drying methods had obvious effects on the color, proximate chemical compositions, total phenolics, antioxidant activity of shiitake mushroom. The FD and ND products exhibited the best rehydration and shrinkage ratio; the effect of FD on color was the least, followed by ND, while MD and ID influenced significantly the color of mushroom; six drying methods had no effects on the content of ash, crude fat and carbohydrate of shiitake mushroom. Drying resulted in the decrease of total phenolic content and antioxidant activity of shiitake mushroom. Among them, the mushroom dried with FD had no obvious changes compared with fresh mushroom