A
bstract
Soft hair of black hole has been proposed recently to play an important role in the resolution of the black hole information paradox. Recent work has emphasized that the soft modes cannot ...affect the black hole S-matrix due to Weinberg soft theorems. However as soft hair is generated by supertranslation of geometry which involves an angular dependent shift of time, it must have non-trivial quantum effects. We consider supertranslation of the Vaidya black hole and construct a non-spherical symmetric dynamical spacetime with soft hair. We show that this spacetime admits a trapping horizon and is a dynamical black hole. We find that Hawking radiation is emitted from the trapping horizon of the dynamical black hole. The Hawking radiation has a spectrum which depends on the soft hair of the black hole and this is consistent with the factorization property of the black hole S-matrix.
A
bstract
According to Witten 1, the conformal boundary condition of gravity, which specifies the conformal geometry of the boundary and the trace of the extrinsic curvature, is elliptic and leads to ...well-defined perturbation theory of gravity about any classical solution. The conformal boundary condition was previously considered in 2, 3 in the context of AdS/BCFT, wherein the equation of motion of the end-of-the-world was derived and emphasized. In this paper, we investigate further other consequences of the conformal boundary condition in AdS/BCFT. We derive the boundary central charges of the holographic Weyl anomaly and show that they are exactly the same for conformal boundary condition and Dirichlet boundary condition. We analysis the metric perturbation with conformal boundary condition (CBC), Dirichlet boundary condition (DBC) and Neumann boundary condition (NBC) imposed on the end-of-the-world brane and show that they admit an interpretation as the fluctuation of the extrinsic curvature (case of CBC and DBC) and the induced metric (case of NBC) of
Q
respectively. In all cases, the fluctuation modes are massive, which are closely relevant to the massive island formation in the literature. Our results reveal that there are non-trivial gravitational dynamics from extrinsic curvatures on the conformal and Dirichlet branes, which may have interesting applications to the island. We also discuss, in passing, the localization of gravitons in brane world theory. We find that, contrary to NBC, the graviton for CBC/DBC is located on the brane with non-positive tension instead of non-negative tension.
A
bstract
We study the entanglement entropy for time-like subsystem in two-dimensional boundary conformal field theory (BCFT) both from the field theory and holographic point of view. In field ...theory, we compute the time-like entanglement entropy of a pure time-like interval at zero and finite temperature using the replica technique and analytical continuation. We find that, similar to the ordinary space-like entanglement entropy in BCFT, the time-like entropy also has a bulk phase and a boundary phase which corresponds respectively to the dominance of the identity block in the bulk and boundary OPE channels. However, we find that in Lorentzian BCFT, the time-like entanglement entropy posses a third
Regge phase
which arises in the Regge limit of the interval, when one endpoint of the time interval approaches the light cone of the mirror image of the other endpoint. We determine the phase diagram for the time-like entanglement entropy. We find that while the time-like entropy is complex in the bulk phase and has a boundary term in the boundary phase, there is no boundary entropy in the Regge phase. Moreover, it can be real or complex depending on which side the Regge limit is approached from. On the gravity side, we obtain the holographic time-like entanglement entropy from the corresponding bulk dual geometries and find exact agreement with the field theory results. The time-like entanglement entropy may be useful to describe the entanglement of a quantum dot on a half line.
A
bstract
Recently, it is found that when an external magnetic field parallel to the boundary is applied, Weyl anomaly gives rises to a new anomalous current transport in the vicinity of the ...boundary. At the leading order of closeness from the boundary, the current is determined universally by the central charge of the theory. In this paper, we give a holographic proof for the existence and universality for this transport phenomena. We show that the current is independent of boundary conditions in four dimensions while it depends on boundary conditions in other dimensions. We also study the backreaction of the bulk Maxwell fields on the AdS spacetime and obtain the holographic Weyl anomaly for 5d BCFTs in presence of the background field strength.
Despite an enormous research effort, most cases of late-onset Alzheimer's disease (LOAD) still remain unexplained and the current biomedical science is still a long way from the ultimate goal of ...revealing clear risk factors that can help in the diagnosis, prevention and treatment of the disease. Current theories about the development of LOAD hinge on the premise that Alzheimer's arises mainly from heritable causes. Yet, the complex, non-Mendelian disease etiology suggests that an epigenetic component could be involved. Using MALDI-TOF mass spectrometry in post-mortem brain samples and lymphocytes, we have performed an analysis of DNA methylation across 12 potential Alzheimer's susceptibility loci. In the LOAD brain samples we identified a notably age-specific epigenetic drift, supporting a potential role of epigenetic effects in the development of the disease. Additionally, we found that some genes that participate in amyloid-beta processing (PSEN1, APOE) and methylation homeostasis (MTHFR, DNMT1) show a significant interindividual epigenetic variability, which may contribute to LOAD predisposition. The APOE gene was found to be of bimodal structure, with a hypomethylated CpG-poor promoter and a fully methylated 3'-CpG-island, that contains the sequences for the epsilon4-haplotype, which is the only undisputed genetic risk factor for LOAD. Aberrant epigenetic control in this CpG-island may contribute to LOAD pathology. We propose that epigenetic drift is likely to be a substantial mechanism predisposing individuals to LOAD and contributing to the course of disease.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
We propose a candidate c-function in arbitrary dimensional quantum field theories with broken Lorentz and rotational symmetry. For holographic theories we derive the necessary and sufficient ...conditions on the geometric background for these c-functions to satisfy the c-theorem. We obtain the null energy conditions for anisotropic background to show that they do not themselves assure the c-theorem. By employing them, we find that it is possible to impose conditions on the UV data that are enough to guarantee at least one monotonic c-function along the RG flow. These UV conditions can be used as building blocks for the construction of anisotropic monotonic RG flows. Finally, we apply our results to several known anisotropic theories and identify the region in the parameter space of the metric where the c-theorem holds for our proposed c-function.
•Feedback and redundancy in RTK signaling complicate cancer treatment.•Co-targeting primary oncogenic signaling and feedback can block drug resistance.•Treatment strategies need to take into account ...the complexity of signaling networks.
Mammalian cells have multiple regulatory mechanisms to deal with perturbations in cellular homeostasis, including feedback loops and crosstalk between the major signaling pathways. While these mechanisms are critically required to help cells survive under dynamic physiological circumstances, they also pose an impediment to the effective treatment of cancer. In this review, we describe what has been learned about interactions between receptor tyrosine kinase-dependent signaling pathways, and how this knowledge can be used to design rational and more effective combination therapies for cancer.
A
bstract
We reveal elegant relations between the shape dependence of the Casimir effects and Weyl anomaly in boundary conformal field theories (BCFT). We show that for any BCFT which has a ...description in terms of an effective action, the near boundary divergent behavior of the renormalized stress tensor is completely determined by the central charges of the theory. These relations are verified by free BCFTs. We also test them with holographic models of BCFT and find exact agreement. We propose that these relations between Casimir coefficients and central charges hold for any BCFT. With the holographic models, we reproduce not only the precise form of the near boundary divergent behavior of the stress tensor, but also the surface counter term that is needed to make the total energy finite. As they are proportional to the central charges, the near boundary divergence of the stress tensor must be physical and cannot be dropped by further artificial renormalization. Our results thus provide affirmative support on the physical nature of the divergent energy density near the boundary, whose reality has been a long-standing controversy in the literature.
Apoptosis shapes brain structure and function during early life. However, aberrant apoptosis, including that associated with the general anaesthetic propofol, is undesirable. Dexmedetomidine (DEX) ...provides potential neuroprotection against apoptosis, but the underlying mechanism remains unknown. We exposed neonatal rodent hippocampal astrocytes to propofol alone and in combination with DEX and yohimbine (an α2‐adrenergic receptor antagonist), then evaluated cell viability using the MTT assay. The underlying regulatory mechanism associated with apoptosis‐related genes was detected using a combinational strategy including double immunofluorescent staining, real‐time reverse transcription polymerase chain reaction (RT‐PCR), western blot, and flow cytometry. Propofol reduced matrix metallopeptidase 9 (MMP9) in cultured astrocytes, and activated the rno‐miR‐665/Bcl2‐like 1 (Bcl2l1)/cleaved caspase 9 (CC9)/cleaved caspase 3 (CC3) pathway. Combinations incorporating propofol with A–1155463 (a selective Bcl2l1 inhibitor) or MMP9 antagomir reduced Bcl2l1 and promoted apoptosis. Co‐culture of propofol with Bcl2l1 or with MMP9 agomir was sufficient to decrease the pro‐apoptotic effects of propofol. Interestingly, DEX alone had no significant effect on apoptosis. When combined with propofol, however, the negative effects of propofol on the MMP9 and apoptosis‐related genes (Bcl2l1, CC9, and CC3) were reduced. Furthermore, yohimbine pretreatment blocked the neuroprotective effects of DEX. Rno‐miR‐665 was also found to reduce MMP9 expression in propofol‐treated hippocampal astrocytes. Taken together, the results indicate that DEX pretreatment reduces propofol‐associated pro‐apoptosis in developing astrocytes via downregulation of anti‐apoptotic signalling mediated by Bcl2l1.
Dexmedetomidine decreases propofol‐induced apoptosis via attenuation of the decrease of Bcl2l1 and astrocyte‐derived MMP9 through the Bcl2l1/cleaved caspase 9/cleaved caspase 3‐mediated apoptotic signalling pathway in healthy developing hippocampal astrocytes in vitro.
On new proposal for holographic BCFT Chu, Chong-Sun; Miao, Rong-Xin; Guo, Wu-Zhong
The journal of high energy physics,
04/2017, Letnik:
2017, Številka:
4
Journal Article
Recenzirano
Odprti dostop
A
bstract
This paper is an extended version of our short letter on a new proposal for holographic boundary conformal field, i.e., BCFT. By using the Penrose-Brown-Henneaux (PBH) transformation, we ...successfully obtain the expected boundary Weyl anomaly. The obtained boundary central charges satisfy naturally a c-like theorem holographically. We then develop an approach of holographic renormalization for BCFT, and reproduce the correct boundary Weyl anomaly. This provides a non-trivial check of our proposal. We also investigate the holographic entanglement entropy of BCFT and find that our proposal gives the expected orthogonal condition that the minimal surface must be normal to the spacetime boundaries if they intersect. This is another support for our proposal. We also find that the entanglement entropy depends on the boundary conditions of BCFT and the distance to the boundary; and that the entanglement wedge behaves a phase transition, which is important for the self-consistency of AdS/BCFT. Finally, we show that the proposal of
arXiv:1105.5165
is too restrictive that it always make vanishing some of the boundary central charges.
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