Numerical Simulation of Hot Accretion Flows (III): Revisiting wind properties using trajectory approach

Previous MHD simulations have shown that wind must exist in black hole hot accretion flows. In this paper, we continue our study by investigating the detailed properties of wind, such as mass flux and poloidal speed, and the mechanism of wind production. For this aim, we make use of a three dimensional GRMHD simulation of hot accretion flows around a Schwarzschild black hole. The simulation is designed so that the magnetic flux is not accumulated significantly around the black hole. To distinguish real wind from turbulent outflows, we track the trajectories of the virtual Largrangian particles from simulation data. We find two types of real outflows, i.e., a quasi-relativistic jet close to the axis and a sub-relativistic wind subtending a much larger solid angle. Most of the wind originates from the surface layer of the accretion flow. The poloidal wind speed almost remains constant once they are produced, but the flux-weighted wind speed roughly follows $v_{\rm p, wind}(r)\approx 0.25 v_k(r)$. The mass flux of jet is much lower but the speed is much higher, $v_{\rm p,jet}\sim (0.3-0.4) c$. Consequently, both the energy and momentum fluxes of the wind are much larger than those of the jet. We find that the wind is produced and accelerated primarily by the combination of centrifugal force and magnetic pressure gradient, while the jet is mainly accelerated by magnetic pressure gradient. Finally, we find that the wind production efficiency $\epsilon_{\rm wind}\equiv\dot{E}_{\rm wind}/\dot{M}_{\rm BH}c^2\sim 1/1000$, in good agreement with the value required from large-scale galaxy simulations with AGN feedback.Comment: 13 pages, 13 figures; submitted to Ap

Factors associated with older people’s long-term care needs: a case study adopting the expanded version of the Anderson Model in China

2016-2017 > Academic research: refereed > Publication in refereed journal201804_a bcmapublished_fina

Deep Virtual-to-Real Distillation for Pedestrian Crossing Prediction

Pedestrian crossing is one of the most typical behavior which conflicts with natural driving behavior of vehicles. Consequently, pedestrian crossing prediction is one of the primary task that influences the vehicle planning for safe driving. However, current methods that rely on the practically collected data in real driving scenes cannot depict and cover all kinds of scene condition in real traffic world. To this end, we formulate a deep virtual to real distillation framework by introducing the synthetic data that can be generated conveniently, and borrow the abundant information of pedestrian movement in synthetic videos for the pedestrian crossing prediction in real data with a simple and lightweight implementation. In order to verify this framework, we construct a benchmark with 4667 virtual videos owning about 745k frames (called Virtual-PedCross-4667), and evaluate the proposed method on two challenging datasets collected in real driving situations, i.e., JAAD and PIE datasets. State-of-the-art performance of this framework is demonstrated by exhaustive experiment analysis. The dataset and code can be downloaded from the website \url{http://www.lotvs.net/code_data/}.Comment: Accepted by ITSC 202

Multi-Task Learning in Conditional Random Fields for Chunking in Shallow Semantic Parsing

PACLIC 23 / City University of Hong Kong / 3-5 December 200

PAP: A Privacy-Preserving Authentication Scheme with Anonymous Payment for V2G Networks

Vehicle-to-grid (V2G) networks, as an emerging smart grid paradigm, can be integrated with renewable energy resources to provide power services and manage electricity demands. When accessing electricity services, an electric vehicle(EV) typically provides authentication or/and payment information containing identifying data to a service provider, which raises privacy concerns as malicious entities might trace EV activity or exploit personal information. Although numerous anonymous authentication and payment schemes have been presented for V2G networks, no such privacy-preserving scheme supports authentication and payment simultaneously. Therefore, this paper is the first to present a privacy-preserving authentication scheme with anonymous payment for V2G networks (PAP, for short). In addition, this scheme also supports accountability and revocability, which are practical features to prevent malicious behavior; minimal attribute disclosure, which maximizes the privacy of EV when responding to the service provider\u27s flexible access policies; payment binding, which guarantees the accountability in the payment phase; user-controlled linkability, which enables EV to decide whether different authentication sessions are linkable for continuous services. On the performance side, we implement PAP with the pairing cryptography library, then evaluate it on different hardware platforms, showing that it is essential for V2G applications

Dynamic Evolution of Eukaryotic Mitochondrial and Nuclear Genomes: A Case Study in the Gourmet Pine Mushroom Tricholoma matsutake

Fungi, as eukaryotic organisms, contain two genomes, the mitochondrial genome and the nuclear genome, in their cells. How the two genomes evolve and correlate to each other is debated. Herein, taking the gourmet pine mushroom Tricholoma matsutake as an example, we performed comparative mitogenomic analysis using samples collected from diverse locations and compared the evolution of the two genomes. The T. matsutake mitogenome encodes 49 genes and is rich of repetitive and non-coding DNAs. Six genes were invaded by up to 11 group I introns, with one cox1 intron cox1P372 showing presence/absence dynamics among different samples. Bioinformatic analyses suggested limited or no evidence of mitochondrial heteroplasmy. Interestingly, hundreds of mitochondrial DNA fragments were found in the nuclear genome, with several larger than 500 nt confirmed by PCR assays and read count comparisons, indicating clear evidence of transfer of mitochondrial DNA into the nuclear genome. Nuclear DNA of T. matsutake showed a higher mutation rate than mitochondrial DNA. Furthermore, we found evidence of incongruence between phylogenetic trees derived from mitogenome and nuclear DNA sequences. Together, our results reveal the dynamic genome evolution of the gourmet pine mushroom.Peer reviewe

Patient perception of treatment efficacy, disability and health satisfaction

Abstract published in Rheumatology, Volume 55 (Suppl 1), April 2016, page i123

Molecular characterization of the envelope gene of dengue virus type 3 newly isolated in Guangzhou, China, during 2009–2010

SummaryBackgroundAfter an absence of 29 years, dengue virus type 3 (DENV-3) re-emerged in Guangzhou in 2009 and again in 2010. However, the geographical route by which the virus entered the city, and how it has changed genetically, remain unclear. Therefore, we carried out a comprehensive investigation into the molecular characteristics of the DENV-3 involved.MethodsThe envelope (E) genes of viruses isolated from dengue patients during the 2009–2010 epidemics were sequenced and compared with previously published E gene sequences of global representative DENV-3 strains available in GenBank, including isolates circulating in other provinces of China.ResultsA total of 13 isolates (seven from 2009 and six from 2010) were obtained from human serum samples. Phylogenetic analysis revealed that the isolates were grouped into three genotypes (I, III, and V) and then two clades within genotype III (genotype I from Indonesia, genotype III clade A from Côte d’Ivoire, genotype III clade B from Tanzania, and genotype V from Philippines). In addition, there were 1.3–9.0% and 0.5–3.9% differences in the nucleic and deduced amino acid sequences between the 2009 and 2010 strains, respectively.ConclusionsThe DENV-3 viruses from the period 2009–2010 were not from the continuous spread of an epidemic strain or the re-emergence of the 2009 strains in the 2-year period. The introduction of different DENV-3 genotypes following more than one geographical route was an important contributing factor to the 2009–2010 dengue epidemics in Guangzhou

Association Between Vitamin D Receptor Gene Polymorphisms and Polycystic Ovary Syndrome Risk: A Meta-Analysis

Objective: Published studies have demonstrated a closer association between vitamin D receptor (VDR) gene polymorphisms and polycystic ovary syndrome (PCOS) risk, but the results were inconsistent. We therefore performed this meta-analysis to explore the precise associations between VDR gene polymorphisms and PCOS risk.Methods: Five online electronic databases (PubMed, Embase, SCI index, CNKI and Wanfang) were searched. Odds ratios (ORs) with 95% confidence interval (CIs) were calculated to assess the association between VDR Fok I C/T (rs10735810), BsmI A/G (rs1544410), ApaI A/C (rs7975232), and TaqI T/C (rs731236) polymorphisms and PCOS risk. In addition, heterogeneity, accumulative/sensitivity analysis and publication bias were conducted to check the statistical power.Results: Overall, 10 publications (31 independent case-control studies) involving 1,531 patients and 1,174 controls were identified. We found that the C mutation of ApaI A/C was a risk factor for PCOS (C vs. A: OR = 1.20, 95%CI = 1.06–1.35, P < 0.01, I2 = 29.7%; CC vs. AA: OR = 1.49, 95%CI = 1.17–1.91, P < 0.01, I2 = 0%; CC vs. AA+AC: OR = 1.36, 95%CI = 1.09–1.69, P = 0.01, I2 = 12.8%). Moreover, the BsmI A/G polymorphism also showed a dangerous risk for PCOS in Asian population (G vs. A: OR = 1.62, 95%CI = 1.24–2.11, P < 0.01, I2 = 0%; AG vs. AA: OR = 2.08, 95%CI = 1.26–3.20, P < 0.01, I2 = 0%; GG vs. AA: OR = 2.21, 95%CI = 1.29–3.77, P < 0.01, I2 = 0%; AG+GG vs. AA: OR = 2.12, 95%CI = 1.42–3.16, P < 0.01, I2 = 0%). In addition, no significant association of Fok I C/T, and TaqI T/C polymorphisms was observed.Conclusions: In summary, our meta-analysis suggested that VDR gene polymorphisms contribute to PCOS development, especially in Asian populations