12,786 research outputs found

    Aspects of Warped AdS3_3/CFT2_2 Correspondence

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    In this paper we apply the thermodynamics method to investigate the holographic pictures for the BTZ black hole, the spacelike and the null warped black holes in three-dimensional topologically massive gravity (TMG) and new massive gravity (NMG). Even though there are higher derivative terms in these theories, the thermodynamics method is still effective. It gives consistent results with the ones obtained by using asymptotical symmetry group (ASG) analysis. In doing the ASG analysis we develop a brute-force realization of the Barnich-Brandt-Compere formalism with Mathematica code, which also allows us to calculate the masses and the angular momenta of the black holes. In particular, we propose the warped AdS3_3/CFT2_2 correspondence in the new massive gravity, which states that quantum gravity in the warped spacetime could holographically dual to a two-dimensional CFT with c_R=c_L=\f{24}{Gm\b^2\sr{2(21-4\b^2)}}.Comment: 22 pages, references added, published version, link of Mathematica code changed to https://s.yunio.com/Mtus0z or http://pan.baidu.com/s/1mToF

    Board diversity and firm performance: impact of ESG activities in China

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    The investigation of association between board diversity and the firm performance is the subject of many studies. However, the empirical results presented in the extant literature are inconclusive at best. The inconclusive empirical results could be due to several factors and one of them could be that the relationship is contingent on some key factors. Given the rising trend of Environmental, Social and Governance (ESG) activities, in this paper the relationship between board diversity and the firm performance is tested in the context of ESG activities. The subject of examination in this study is the listed Chinese firms. The sample period spans for 6 years and is collected from 2014 to 2019. This work uses a dynamic approach to modelling relationships. The generalised method of moments (GMM) is used in a two-step system. An endogeneity-free estimate may be achieved by using this strategy. We can learn a great deal from these hypotheses. There is a positive and substantial correlation between board diversity and the firm’s success, which suggests that diverse boards are beneficial to businesses. Both ESG activities and a positive coefficient on company performance are significant. This shows investors appreciate companies that are involved in ESG activities because they see this as an investment that pays off. Last but not least, the report shows that board diversity has a negative and considerable impact on ESG efforts. According to the results, board diversity and ESG efforts are not necessary for a company’s success. According to the data, board diversity is not particularly beneficial in the context of significant ESG initiatives. Board diversity really hurts a company’s success when it engages in high ESG activities. The study also discusses the work’s policy ramifications. Finally, the work lays out a clear path for further study

    BMP9-Induced Osteogenetic Differentiation and Bone Formation of Muscle-Derived Stem Cells

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    Efficient osteogenetic differentiation and bone formation from muscle-derived stem cells (MDSCs) should have potential clinical applications in treating nonunion fracture healing or bone defects. Here, we investigate osteogenetic differentiation ability of MDSCs induced by bone morphogenetic protein 9 (BMP9) in vitro and bone formation ability in rabbit radius defects repairing model. Rabbit's MDSCs were extracted by type I collagenase and trypsin methods, and BMP9 was introduced into MDSCs by infection with recombinant adenovirus. Effects of BMP9-induced osteogenetic differentiation of MDSCs were identified with alkaline phosphatase (ALP) activity and expression of later marker. In stem-cell implantation assay, MDSCs have also shown valuable potential bone formation ability induced by BMP9 in rabbit radius defects repairing test. Taken together, our findings suggest that MDSCs are potentiated osteogenetic stem cells which can be induced by BMP9 to treat large segmental bone defects, nonunion fracture, and/or osteoporotic fracture

    Discovery of gamma-ray emission from a strongly lobe-dominated quasar 3C 275.1

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    We systematically analyze the 6-year {\it Fermi}/LAT data of the lobe-dominated quasars (LDQs) in the complete LDQ sample from 3CRR survey and report the discovery of high-energy γ\gamma-ray emission from 3C 275.1. The γ\gamma-ray emission of 3C 207 is confirmed and significant variability of the lightcurve is identified. We do not find statistically significant γ\gamma-ray emission from other LDQs. 3C 275.1 is the known γ\gamma-ray quasar with the lowest core dominance parameter (i.e., R=0.11R=0.11). We also show that both the northern radio hotspot and parsec jet models can reasonably reproduce the γ\gamma-ray data. The parsec jet model, however, is favored by the potential γ\gamma-ray variability at the timescale of months. We suggest that some dimmer γ\gamma-ray LDQs will be detected in the future and LDQs could contribute non-negligibly to the extragalactic γ\gamma-ray background.Comment: 26 pages, 10 figures, 3 tables; ApJ in pres

    Experimental study on penetration of dental implants into the maxillary sinus in different depths

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    The exposing of dental implant into the maxillary sinus combined with membrane perforation might increase risks of implant failure and sinus complications. Objective: The purpose of this study was to investigate the effects of the dental implant penetration into the maxillary sinus cavity in different depths on osseointegration and sinus health in a dog model. Material and Methods: Sixteen titanium implants were placed in the bilateral maxillary molar areas of eight adult mongrel dogs, which were randomly divided into four groups according to the different penetrating extents of implants into the sinus cavities (group A: 0 mm; group B: 1 mm; group C: 2 mm; group D: 3 mm). The block biopsies were harvested five months after surgery and evaluated by radiographic observation and histological analysis. Results: No signs of inflammatory reactions were observed in any maxillary sinus of the eight dogs. The tips of the implants with penetrating depth of 1 mm and 2 mm were found to be fully covered with newly formed membrane and partially with new bone. The tips of the implants with penetrating depth over 3 mm were exposed in the sinus cavity and showed no membrane or bone coverage. No significant differences were found among groups regarding implant stability, bone-to-implant contact (BIC) and bone area in the implant threads (BA). Conclusions: Despite the protrusion extents, penetration of dental implant into the maxillary sinus with membrane perforation does not compromise the sinus health and the implant osseointegration in canine
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