Harnessing heterogeneous social networks for better recommendations: A grey relational analysis approach

Most of the extant studies in social recommender system are based on explicit social relationships, while the potential of implicit relationships in the heterogeneous social networks remains largely unexplored. This study proposes a new approach to designing a recommender system by employing grey relational analysis on the heterogeneous social networks. It starts with the establishment of heterogeneous social networks through the user-item bipartite graph, user social network graph and user-attribute bipartite graph; and then uses grey relational analysis to identify implicit social relationships, which are then incorporated into the matrix factorization model. Five experiments were conducted to test the performance of our approach against four state-of-the-art baseline methods. The results show that compared with the baseline methods, our approach can effectively alleviate the sparsity problem, because the heterogeneous social network provides richer information. In addition, the grey relational analysis method has the advantage of low requirements for data size and efficiently relieves the cold start problem. Furthermore, our approach saves processing time, thus increases recommendation efficiency. Overall, the proposed approach can effectively improve the accuracy of rating prediction in social recommendations and provide accurate and efficient recommendation service for users

LL-valley electron gg factor in bulk GaAs and AlAs

We study the Land\'e $g$-factor of conduction electrons in the $L$-valley of bulk GaAs and AlAs by using a three-band $\mathbf{k}\cdot\mathbf{p}$ model together with the tight-binding model. We find that the $L$-valley $g$-factor is highly anisotropic, and can be characterized by two components, $g_{\perp}$ and $g_{\|}$. $g_{\perp}$ is close to the free electron Land\'e factor but $g_{\|}$ is strongly affected by the remote bands. The contribution from remote bands on $g_{\|}$ depends on how the remote bands are treated. However, when the magnetic field is in the Voigt configuration, which is widely used in the experiments, different models give almost identical $g$-factor.Comment: 4 pages, 1 figure, To be published in J. App. Phys. 104, 200

Entanglement renormalization of anisotropic XY model

The renormalization group flows of the one-dimensional anisotropic XY model and quantum Ising model under a transverse field are obtained by different multiscale entanglement renormalization ansatz schemes. It is shown that the optimized disentangler removes the short-range entanglement by rotating the system in the parameter space spanned by the anisotropy and the magnetic field. It is understood from the study that the disentangler reduces the entanglement by mapping the system to another one in the same universality class but with smaller short range entanglement. The phase boundary and corresponding critical exponents are calculated using different schemes with different block sizes, look-ahead steps and truncation dimensions. It is shown that larger truncation dimension leads to more accurate results and that using larger block size or look-ahead step improve the overall calculation consistency.Comment: 5 pages, 3 figure

Immunohistochemical evidence: testicular and scented glandular androgen synthesis in muskrats (Ondatra zibethicus) during the breeding season

In order to elucidate the relationship between androgens and the function of the muskrat (Ondatra zibethicus) scented glands during the breeding season, we investigated immunolocalization of steroidogenic enzymes P450scc, 3βHSD and P450c17 in the muskrat testes and scented glands. Nine adult muskrats were obtained in March (n=3), May (n=3) and July (n=3) 2010. Steroidogenic enzymes were immunolocalized using polyclonal antisera raised against bovine adrenal P450scc, human placental 3βHSD and porcine testicular P450c17. Histologically, all types of spermatogenic cells including mature-phase spermatozoa in seminiferous tubules were observed in all testes. Glandular cells, interstitial cells, epithelial cells and excretory tubules were identified in scented glands during the breeding season. P450scc, 3βHSD and P450c17 were only identified in Leydig cells during the breeding season; P450scc and P450c17 were observed in glandular cells of scented glands, however, 3βHSD was not found in scented glands during the breeding season. These novel findings provide the first evidence showing that scented glands of the muskrats are capable of locally synthesizing androgens and androgens acting via an endocrine, autocrine or paracrine manner may play an important role in scented gland function during the breeding season