Hawking radiation, W-infinity algebra and trace anomalies

We apply the "trace anomaly method" to the calculation of moments of the Hawking radiation of a Schwarzschild black hole. We show that they can be explained as the fluxes of chiral currents forming a W-infinity algebra. Then we construct the covariant version of these currents and verify that up to order 6 they are not affected by any trace anomaly. Using cohomological methods we show that actually, for the fourth order current, no trace anomalies can exist. The results reported here are strictly valid in two dimensions.Comment: 22 pages, typos correcte

Hawking Fluxes, Back reaction and Covariant Anomalies

Starting from the chiral covariant effective action approach of Banerjee and Kulkarni [Phys. Lett. B 659, 827(2008)], we provide a derivation of the Hawking radiation from a charged black hole in the presence of gravitational back reaction. The modified expressions for charge and energy flux, due to effect of one loop back reaction are obtained.Comment: 6 pages, no figures, minor changes and references added, to appear in Classical and Quantum Gravit

Hawking radiation from the Schwarzschild black hole with a global monopole via gravitational anomaly

Hawking flux from the Schwarzschild black hole with a global monopole is obtained by using Robinson and Wilczek's method. Adopting a dimension reduction technique, the effective quantum field in the (3+1)--dimensional global monopole background can be described by an infinite collection of the (1+1)--dimensional massless fields if neglecting the ingoing modes near the horizon, where the gravitational anomaly can be cancelled by the (1+1)--dimensional black body radiation at the Hawking temperature.Comment: 4 pages, no figure, 3nd revsion with one reference adde

Anomalies and Hawking radiation from the Reissner-Nordstr\"om black hole with a global monopole

We extend the work by S. Iso, H. Umetsu and F. Wilczek [Phys. Rev. Lett. 96 (2006) 151302] to derive the Hawking flux via gauge and gravitational anomalies of a most general two-dimensional non-extremal black hole space-time with the determinant of its diagonal metric differing from the unity ($\sqrt{-g} \neq 1$) and use it to investigate Hawking radiation from the Reissner-Nordstrom black hole with a global monopole by requiring the cancellation of anomalies at the horizon. It is shown that the compensating energy momentum and gauge fluxes required to cancel gravitational and gauge anomalies at the horizon are precisely equivalent to the $(1+1)$-dimensional thermal fluxes associated with Hawking radiation emanating from the horizon at the Hawking temperature. These fluxes are universally determined by the value of anomalies at the horizon.Comment: 18 pages, 0 figure. 1 footnote and 4 new reference adde

Effect of Chinese medical herbs- burn liniment on deep second degree burn in rats

Background: Burn Liniment (BL) is a popular traditional Chinese medicine formula consisting five herbal medicines (Flos Lonicerae, Rhizoma Polygoni Cuspidati, Pericarpium Granati,Terminalia chebula Retz. and Galla Chinensis), that has been used in China for centuries to cure burn. This study investigated the healing effect of BL on deep second degree burn wounds in rats.Materials and methods: The animals were divided into four groups including control group, model group,1% silver sulfadiazine (SSD) group and BL group. On days 0,3,7,14 and 21,animal weight, wound area as well as histo-pathological observations of the skin were evaluated in different groups. Serum anti-intercellular adhesion molecule 1(ICAM-1), IL-10 levels and myeloperoxidase (MPO) activity were measured on the 21st day. HPLC chromatography of BL was prepared and concentrations of active constituents were determined. Antibacterial test and toxicological test were also performed.Results: The average wound area of BL treatment group was also significantly smaller than model control rats on days 14 and 21. Serum anti-intercellular adhesion molecule 1(ICAM-1) levels and myeloperoxidase (MPO) activity of BL group decreased significantly than in model rats on day 21 while IL-10 level of BL group increased remarkably than in model rats on the 21st day, showing that BL has strong anti-inflammatory activity on burned rats. The histological studies indicated that inflammatory cells disappeared significantly and were replaced by new granulation tissue, and epithelialization progressed quickly and was treated with BL on the 21st day. Meanwhile, HPLC chromatography of BL was prepared and concentration of Chlorogenic acid, Polydatin and Gallic acid from BL were determined. Antibacterial test revealed that the MIC of BL on Staphyloccocus aureus, Pseudomonas aeruginosa and Escherichia coli were 1.56, 6.25 and 1.56 mg·mL-1 respectively. Toxicological test showed that BL does not induce skin irritation or sensitivity signs and has no acute toxicity reaction.Conclusions: Our study revealed that BL could enhance cutaneous burn wound healing effectively. It also showed strong anti-inflammatory and antibacterial activity in rats.Keywords: Burn Liniment; Deep second degree; Burn wound; Anti-inflammatory; Antibacterial; Toxicological tes

Fermions tunnelling from the charged dilatonic black holes

Kerner and Mann's recent work shows that, for an uncharged and non-rotating black hole, its Hawking temperature can be exactly derived by fermions tunnelling from its horizons. In this paper, our main work is to improve the analysis to deal with charged fermion tunnelling from the general dilatonic black holes, specifically including the charged, spherically symmetric dilatonic black hole, the rotating Einstein-Maxwell-Dilaton-Axion (EMDA) black hole and the rotating Kaluza-Klein (KK) black hole. As a result, the correct Hawking temperatures are well recovered by charged fermions tunnelling from these black holes.Comment: 16 pages, revised version to appear in Class. Quant. Gra

Back reaction, covariant anomaly and effective action

In the presence of back reaction, we first produce the one-loop corrections for the event horizon and Hawking temperature of the Reissner-Nordstr\"om black hole. Then, based on the covariant anomaly cancelation method and the effective action technique, the modified expressions for the fluxes of gauge current and energy momentum tensor, due to the effect of back reaction, are obtained. The results are consistent with the Hawking fluxes of a (1+1)-dimensional blackbody at the temperature with quantum corrections, thus confirming the robustness of the covariant anomaly cancelation method and the effective action technique for black holes with back reaction.Comment: 17 page

Enhancing Transport Efficiency by Hybrid Routing Strategy

Traffic is essential for many dynamic processes on real networks, such as internet and urban traffic systems. The transport efficiency of the traffic system can be improved by taking full advantage of the resources in the system. In this paper, we propose a dual-strategy routing model for network traffic system, to realize the plenary utility of the whole network. The packets are delivered according to different "efficient routing strategies" [Yan, et al, Phys. Rev. E 73, 046108 (2006)]. We introduce the accumulate rate of packets, {\eta} to measure the performance of traffic system in the congested phase, and propose the so-called equivalent generation rate of packet to analyze the jamming processes. From analytical and numerical results, we find that, for suitable selection of strategies, the dual- strategy system performs better than the single-strategy system in a broad region of strategy mixing ratio. The analytical solution to the jamming processes is verified by estimating the number of jammed nodes, which coincides well with the result from simulation.Comment: 6 pages, 3 figure

The effect of secondhand smoke exposure on self-satisfaction and perceived freedom of life choice

Objective: The present study aims to examine whether secondhand smoke exposure (SHSE) in university students can affect three indices of self-satisfaction related to depression as indiced by appearance, weight, and freedom of life choice. Participants: We collected data from 740 nonsmoking students in the summer of 2018, of which 57.84% were exposed to secondhand smoke. Methods: Depressive symptoms, SHSE, smoking status, weight satisfaction, appearance satisfaction, and freedom of life choice were self-reported via a questionnaire. Results: The generalized linear analyses revealed that SHSE was linked to lower scores of perceived freedom of life choice but not significantly associated with weight nor appearance satisfaction. The mediation analyses indicated that perceived freedom of life choice fully mediated the association between SHSE and depressive symptoms. Conclusions: These findings shed light on the importance of SHSE and its effects on mental health in university students. Preventive strategies should therefore locally target university campuses