Direct measurement of the quantum state of photons in a cavity

We propose a scheme to measure the quantum state of photons in a cavity. The proposal is based on the concept of quantum weak values and applies equally well to both the solid-state circuit and atomic cavity quantum electrodynamics (QED) systems. The proposed scheme allows us to access directly the superposition components in Fock state basis, rather than the Wigner function as usual in phase space. Moreover, the separate access feature held in the direct scheme does not require a global reconstruction for the quantum state, which provides a particular advantage beyond the conventional method of quantum state tomography.Comment: 6 pages, 2 figure

Modeling the clustering in citation networks

For the study of citation networks, a challenging problem is modeling the high clustering. Existing studies indicate that the promising way to model the high clustering is a copying strategy, i.e., a paper copies the references of its neighbour as its own references. However, the line of models highly underestimates the number of abundant triangles observed in real citation networks and thus cannot well model the high clustering. In this paper, we point out that the failure of existing models lies in that they do not capture the connecting patterns among existing papers. By leveraging the knowledge indicated by such connecting patterns, we further propose a new model for the high clustering in citation networks. Experiments on two real world citation networks, respectively from a special research area and a multidisciplinary research area, demonstrate that our model can reproduce not only the power-law degree distribution as traditional models but also the number of triangles, the high clustering coefficient and the size distribution of co-citation clusters as observed in these real networks

Bridgeness: A Local Index on Edge Significance in Maintaining Global Connectivity

Edges in a network can be divided into two kinds according to their different roles: some enhance the locality like the ones inside a cluster while others contribute to the global connectivity like the ones connecting two clusters. A recent study by Onnela et al uncovered the weak ties effects in mobile communication. In this article, we provide complementary results on document networks, that is, the edges connecting less similar nodes in content are more significant in maintaining the global connectivity. We propose an index named bridgeness to quantify the edge significance in maintaining connectivity, which only depends on local information of network topology. We compare the bridgeness with content similarity and some other structural indices according to an edge percolation process. Experimental results on document networks show that the bridgeness outperforms content similarity in characterizing the edge significance. Furthermore, extensive numerical results on disparate networks indicate that the bridgeness is also better than some well-known indices on edge significance, including the Jaccard coefficient, degree product and betweenness centrality.Comment: 10 pages, 4 figures, 1 tabl

Direct fiber vector eigenmode multiplexing transmission seeded by integrated optical vortex emitters

Spatial modes have received substantial attention over the last decades and are used in optical communication applications. In fiber-optic communications, the employed linearly polarized modes and phase vortex modes carrying orbital angular momentum can be synthesized by fiber vector eigenmodes. To improve the transmission capacity and miniaturize the communication system, straightforward fiber vector eigenmode multiplexing and generation of fiber-eigenmode-like polarization vortices (vector vortex modes) using photonic integrated devices are of substantial interest. Here, we propose and demonstrate direct fiber vector eigenmode multiplexing transmission seeded by integrated optical vortex emitters. By exploiting vector vortex modes (radially and azimuthally polarized beams) generated from silicon microring resonators etched with angular gratings, we report data-carrying fiber vector eigenmode multiplexing transmission through a 2-km large-core fiber, showing low-level mode crosstalk and favorable link performance. These demonstrations may open up added capacity scaling opportunities by directly accessing multiple vector eigenmodes in the fiber and provide compact solutions to replace bulky diffractive optical elements for generating various optical vector beams

White, Man, and Highly Followed: Gender and Race Inequalities in Twitter

Social media is considered a democratic space in which people connect and interact with each other regardless of their gender, race, or any other demographic factor. Despite numerous efforts that explore demographic factors in social media, it is still unclear whether social media perpetuates old inequalities from the offline world. In this paper, we attempt to identify gender and race of Twitter users located in U.S. using advanced image processing algorithms from Face++. Then, we investigate how different demographic groups (i.e. male/female, Asian/Black/White) connect with other. We quantify to what extent one group follow and interact with each other and the extent to which these connections and interactions reflect in inequalities in Twitter. Our analysis shows that users identified as White and male tend to attain higher positions in Twitter, in terms of the number of followers and number of times in user's lists. We hope our effort can stimulate the development of new theories of demographic information in the online space.Comment: In Proceedings of the IEEE/WIC/ACM International Conference on Web Intelligence (WI'17). Leipzig, Germany. August 201

Sleep-disordered breathing is associated with depletion of circulating endothelial progenitor cells and elevation in pulmonary arterial pressure in patients with decompensated systolic heart failure

BACKGROUND: Sleep-disordered breathing (SDB) is known to occur frequently in and may predict worsening progression of patients with congestive heart failure (CHF). SDB is also known to play an important role in the development of idiopathic pulmonary arterial hypertension (PAH) via inducing endothelial dysfunction and vascular remodeling, a pathological process that can be significantly influenced by factors such as osteoprotegerin (OPG) and endothelial progenitor cells (EPCs). The objective of this study is to determine if CHF with SDB is associated with changes in OPG, EPCs, and PAH. METHODS: EPCs were isolated, cultured, and quantified from CHF patients with SDB (n = 52), or without SDB (n = 68). OPG and N-terminal pro-brain natriuretic peptide (NT-proBNP) from each group was analyzed and correlated with EPCs and the mean pulmonary artery pressure (mPAP) measured by right heart catheterization. RESULTS: A significant decrease in circulating EPCs (29.30 ± 9.01 vs. 45.17 ± 10.51 EPCs/× 200 field; P < 0.05) was found in CHF patients with SDB compared to those without SDB. Both OPG (789.83 ± 89.38 vs. 551.29 ± 42.12 pg/mL; P < 0.05) and NT-proBNP (5946.50 ± 1434.50 vs. 3028.60 ± 811.90 ng/mL; P < 0.05) were also significantly elevated in SDB CHF patients who also had significantly elevated mPAP (50.2 ± 9.5 vs. 36.4 ± 4.1 mm Hg; P < 0.05). EPC numbers correlated inversely with the episodes of apnea and hypopnea per hour (RDI, r = -0.45, P = 0.037) and blood level of OPG (r = -0.53, P = 0.011). Although NT-proBNP was also increased significantly in patients with SDB, it had no correlation with either EPCs or RDI. CONCLUSIONS: SDB due to hypoxemia from decompensated CHF is associated with (1) OPG elevation, (2) EPC depletion, and (3) mPAP elevation. The inverse relationship of circulating OPG with EPCs suggests a likely mechanism for hypoxemia and OPG in the development of pulmonary vascular dysfunction via depleting EPCs, thus worsening prognosis of CHF

Serum γ-glutamyltransferase and uric acid levels are associated with impaired fasting glucose in adults from Inner Mongolia, China

BACKGROUND: Serum γ-glutamyltransferase (GGT) and uric acid (UA) levels are elevated in patients with diabetes or cardiovascular disease. Prediabetes, characterized by impaired glucose tolerance, is an important risk factor for overt diabetes as well as cardiovascular disease. Therefore, the aim of this study was to explore the relationship between GGT, UA and prediabetes in a Chinese population, and provide a scientific basis for the early prevention and treatment of diabetes. METHODS: We performed a cross-sectional population-based study in a cohort of 2694 subjects (1211 men and 1483 women, aged 35–86 years). Questionnaires and physical examinations were performed using standardized procedures. Fasting blood was collected to measure glucose and other biochemical parameters. The subjects were divided into two groups with either normal fasting glucose (NFG) or impaired fasting glucose (IFG), according to international diagnostic criteria. Logistic regression analysis was performed to estimate odds ratios (OR) and 95% confidence intervals. RESULTS: Compared with the NFG group, the IFG group had significantly higher blood pressure but lower high-density lipoprotein–cholesterol in women. Body mass index, waist circumference, triglyceride, glucose, GGT, and UA levels were significantly higher in males and females in the IFG group than those in the NFG group. Logistic regression analysis revealed that the OR for prediabetes increased with increasing serum GGT quartiles and UA quartiles. GGT and UA were positively associated with prediabetes in men and women, independent of age, ethnicity, smoking, alcohol consumption, blood pressure, physical labor, and other confounders. CONCLUSIONS: We found that serum GGT and UA levels were positively associated with prediabetes in men and women living in areas inhabited by Chinese ethnic minorities. As elevated GGT and UA levels were associated with significantly increased risk of prediabetes, they may be used as sensitive biological markers of prediabetes