Matter-Antimatter Asymmetry Induced by a Running Vacuum Coupling

We show that a CP-violating interaction induced by a derivative coupling between the running vacuum and a non-conserving baryon current may dynamically break CPT and trigger baryogenesis through an effective chemical potential. By assuming a non-singular class of running vacuum cosmologies which provides a complete cosmic history (from an early inflationary de Sitter stage to the present day quasi-de Sitter acceleration), it is found that an acceptable baryon asymmetry is generated for many different choices of the model parameters. It is interesting that the same ingredient (running vacuum energy density) addresses several open cosmological questions/problems: avoids the initial singularity, provides a smooth exit for primordial inflation, alleviates both the coincidence and the cosmological constant problems, and, finally, is also capable of explaining the generation of matter-antimatter asymmetry in the very early Universe.Comment: 6 pages two column format, 1 table. Published version EPJ

Challenges in Timed Languages: From Applied Theory to Basic Theory

The Concurrency Column, by Luca Aceto. Partially based on the invited talk at FORMATS'03 workshopCurrent state and perspectives of development of the theory of timed languages are analyzed. A large list of open problems is suggested

Generalized Finite Algorithms for Constructing Hermitian Matrices with Prescribed Diagonal and Spectrum

In this paper, we present new algorithms that can replace the diagonal entries of a Hermitian matrix by any set of diagonal entries that majorize the original set without altering the eigenvalues of the matrix. They perform this feat by applying a sequence of (N-1) or fewer plane rotations, where N is the dimension of the matrix. Both the Bendel-Mickey and the Chan-Li algorithms are special cases of the proposed procedures. Using the fact that a positive semidefinite matrix can always be factored as \mtx{X^\adj X}, we also provide more efficient versions of the algorithms that can directly construct factors with specified singular values and column norms. We conclude with some open problems related to the construction of Hermitian matrices with joint diagonal and spectral properties

Thoracoscopic spine surgery for decompression and stabilization of the anterolateral thoracolumbar spine

Journal ArticleThe anterior thoracolumbar spine can be exposed via a variety of approaches. Historically, open anterolateral or posterolateral approaches have been used to gain access to the anterior thoracolumbar spinal column. Although the exposure is excellent, open approaches are associated with significant pain and respiratory problems, substantial blood loss, poor cosmesis, and prolonged hospitalization. With the increasing use of the endoscope in surgical procedures and recent advances in video-assisted thoracoscopic surgery, minimally invasive thoracoscopic spine surgery has been developed to decrease the morbidity associated with open thoracotomy. The purpose of this article is to illustrate the surgical technique of a minimally invasive thoracoscopic approach to the anterolateral thoracolumbar spine and to discuss its potential indications and contraindications in patients with diseases involving the anterior thoracic and lumbar regions

Logic on words

First published in the Bulletin of the European Association of Theoretical Computer Science 54 (1994), 145-165.This dialog between Quisani, Yuri Gurevich's imaginary student, and the author, was published in the "Logic in Computer Science Column" of the EATCS Bulletin. It is first addressed to logicians. This dialog is an occasion to present the connections between Büchi's sequential calculus and the theory of finite automata. In particular, the essential role of first order formulæ is emphasized. The quantifier hierarchies on these formulæ are an occasion to present open problems