Factors That Could Impact on Liver Fibrosis Staging by Transient Elastography.

PublishedReviewTransient elastography (TE) based on liver stiffness measurement (LSM) is one of the most validated noninvasive methods for liver fibrosis staging in patients with chronic liver diseases. This method is painless, has no potential complications, is rapid (100 exams), in a 3-hour fasting status, and its results should be handled by specialist clinicians that are aware of the limitations of this method.This work was supported by funding from Newton Fund RCUK-CONFAP Research Partnerships Call, Fundac¸ao Car- ˜ los Chagas Filho de Amparo a Pesquisa do Estado do Rio ` de Janeiro (FAPERJ) under Grant E-26/170.021/2015 (Brazil), and Medical Research Council (MRC) Grant reference MR/ M026515/1 (UK); from Conselho Nacional de Desenvolvimento Cient´ıfico e Tecnologico (CNPq)/Bolsa Jovem Talento ´ (BJT) under Grant 301520/2014-3; from FAPERJ under Grant E-26/110.268/2014; and from Fundac¸ao para Desenvolvi- ˜ mento Cientifico e Tecnologico em Sa ´ ude (FioTec), Rio de ´ Janeiro, Brazil

Finiteness and orbifold Vertex Operator Algebras

In this paper, I investigate the ascending chain condition of right ideals in the case of vertex operator algebras satisfying a finiteness and/or a simplicity condition. Possible applications to the study of finiteness of orbifold VOAs is discussed.Comment: 12 pages, comments are welcom

On classical finite and affine W-algebras

This paper is meant to be a short review and summary of recent results on the structure of finite and affine classical W-algebras, and the application of the latter to the theory of generalized Drinfeld-Sokolov hierarchies.Comment: 12 page

On the crossing relation in the presence of defects

The OPE of local operators in the presence of defect lines is considered both in the rational CFT and the $c>25$ Virasoro (Liouville) theory. The duality transformation of the 4-point function with inserted defect operators is explicitly computed. The two channels of the correlator reproduce the expectation values of the Wilson and 't Hooft operators, recently discussed in Liouville theory in relation to the AGT conjecture.Comment: TEX file with harvmac; v3: JHEP versio

Anomalous diffusion in polymers: long-time behaviour

We study the Dirichlet boundary value problem for viscoelastic diffusion in polymers. We show that its weak solutions generate a dissipative semiflow. We construct the minimal trajectory attractor and the global attractor for this problem.Comment: 13 page

Homological algebra for osp(1/2n)

We discuss several topics of homological algebra for the Lie superalgebra osp(1|2n). First we focus on Bott-Kostant cohomology, which yields classical results although the cohomology is not given by the kernel of the Kostant quabla operator. Based on this cohomology we can derive strong Bernstein-Gelfand-Gelfand resolutions for finite dimensional osp(1|2n)-modules. Then we state the Bott-Borel-Weil theorem which follows immediately from the Bott-Kostant cohomology by using the Peter-Weyl theorem for osp(1|2n). Finally we calculate the projective dimension of irreducible and Verma modules in the category O

Lunin-Maldacena backgrounds from the classical Yang-Baxter equation -- Towards the gravity/CYBE correspondence

We consider \gamma-deformations of the AdS_5xS^5 superstring as Yang-Baxter sigma models with classical r-matrices satisfying the classical Yang-Baxter equation (CYBE). An essential point is that the classical r-matrices are composed of Cartan generators only and then generate abelian twists. We present examples of the r-matrices that lead to real \gamma-deformations of the AdS_5xS^5 superstring. Finally we discuss a possible classification of integrable deformations and the corresponding gravity solution in terms of solutions of CYBE. This classification may be called the gravity/CYBE correspondence.Comment: 18 pages, no figure, LaTeX, v2:references and further clarifications adde

Optimization of resource allocation for V2X security communication based on multi-agent reinforcement learning

In order to address the data security and communication efficiency of vehicles during high-speed mobile communication, this paper investigates the problem of secure in-vehicle communication resource allocation based on slow-variable large-scale fading channel information, to meet the quality of service requirements of vehicular communication, i.e., to ensure the reliability of V2V communication and the time delay while maximizing the transmission rate of the cellular link. And an eavesdropping model is introduced to ensure the secure delivery of link information. Considering that the high mobility of vehicles causes rapid channel changes, we model the problem as a Markov decision process and propose a resource allocation optimization framework based on the Multi-Agent Reinforcement Learning Algorithm (MARL-DDQN), in which a large-scale neural network model is built to train vehicular to learn the optimal resource allocation strategy for optimal communication performance and security performance. Simulation results show that the load successful delivery rate and confidentiality performance of the vehicular communication network are effectively improved compared to the baseline and MADDPG strategies while ensuring link security. This study provides useful references and practical value for the optimization of secure communication resource allocation in vehicular networking

Mesons from global Anti-de Sitter space

In the context of gauge/gravity duality, we study both probe D7-- and probe D5--branes in global Anti-de Sitter space. The dual field theory is N=4 theory on R x S^3 with added flavour. The branes undergo a geometrical phase transition in this geometry as function of the bare quark mass m_q in units of 1/R with R the S^3 radius. The meson spectra are obtained from fluctuations of the brane probes. First, we study them numerically for finite quark mass through the phase transition. Moreover, at zero quark mass we calculate the meson spectra analytically both in supergravity and in free field theory on R x S^3 and find that the results match: For the chiral primaries, the lowest level is given by the zero point energy or by the scaling dimension of the operator corresponding to the fluctuations, respectively. The higher levels are equidistant. Similar results apply to the descendents. Our results confirm the physical interpretation that the mesons cannot pair-produce any further when their zero-point energy exceeds their binding energy.Comment: 43 pages, 8 figures, references edited, few typos corrected, updated to match the published versio