Some exact solutions with torsion in 5-D Einstein-Gauss-Bonnet gravity

Exact solutions with torsion in Einstein-Gauss-Bonnet gravity are derived. These solutions have a cross product structure of two constant curvature manifolds. The equations of motion give a relation for the coupling constants of the theory in order to have solutions with nontrivial torsion. This relation is not the Chern-Simons combination. One of the solutions has a $AdS_2\times S^3$ structure and is so the purely gravitational analogue of the Bertotti-Robinson space-time where the torsion can be seen as the dual of the covariantly constant electromagnetic field.Comment: 19 pages, LaTex, no figures. References added, notation clarified. Accepted for publication on Physical Review

Integrals of motion and the shape of the attractor for the Lorenz model

In this paper, we consider three-dimensional dynamical systems, as for example the Lorenz model. For these systems, we introduce a method for obtaining families of two-dimensional surfaces such that trajectories cross each surface of the family in the same direction. For obtaining these surfaces, we are guided by the integrals of motion that exist for particular values of the parameters of the system. Nonetheless families of surfaces are obtained for arbitrary values of these parameters. Only a bounded region of the phase space is not filled by these surfaces. The global attractor of the system must be contained in this region. In this way, we obtain information on the shape and location of the global attractor. These results are more restrictive than similar bounds that have been recently found by the method of Lyapunov functions.Comment: 17 pages,12 figures. PACS numbers : 05.45.+b / 02.30.Hq Accepted for publication in Physics Letters A. e-mails : [email protected] & [email protected]

Experimental Realization of Optimal Noise Estimation for a General Pauli Channel

We present the experimental realization of the optimal estimation protocol for a Pauli noisy channel. The method is based on the generation of 2-qubit Bell states and the introduction of quantum noise in a controlled way on one of the state subsystems. The efficiency of the optimal estimation, achieved by a Bell measurement, is shown to outperform quantum process tomography

On the number of limit cycles of the Lienard equation

In this paper, we study a Lienard system of the form dot{x}=y-F(x), dot{y}=-x, where F(x) is an odd polynomial. We introduce a method that gives a sequence of algebraic approximations to the equation of each limit cycle of the system. This sequence seems to converge to the exact equation of each limit cycle. We obtain also a sequence of polynomials R_n(x) whose roots of odd multiplicity are related to the number and location of the limit cycles of the system.Comment: 10 pages, 5 figures. Submitted to Physical Review

Machine learning and multidrug-resistant gram-negative bacteria: An interesting combination for current and future research

The dissemination of multidrug-resistant Gram-negative bacteria (MDR-GNB) is associated with increased morbidity and mortality in several countries. Machine learning (ML) is a branch of artificial intelligence that consists of conferring on computers the ability to learn from data. In this narrative review, we discuss three existing examples of the application of ML algorithms for assessing three different types of risk: (i) the risk of developing a MDR-GNB infection, (ii) the risk of MDR-GNB etiology in patients with an already clinically evident infection, and (iii) the risk of anticipating the emergence of MDR in GNB through the misuse of antibiotics. In the next few years, we expect to witness an increasingly large number of research studies perfecting the application of ML techniques in the field of MDR-GNB infections. Very importantly, this cannot be separated from the availability of a continuously refined and updated ethical framework allowing an appropriate use of the large datasets of medical data needed to build efficient ML-based support systems that could be shared through appropriate standard infrastructures

Is executive function associatedwith symptom severity in schizophrenia?

Abstract.: This paper reports on a study that was designed to investigate the relationship between psychopathology and executive functions in schizophrenia. Correlations were sparse and mostly weak. The most robust finding was the association between letter fluency and negative symptoms; however, most other applied tasks were not associated with symptom level. Our results support previous findings of differential relationships between impaired executive functions and symptom leve

Surgical management of rhinosinusitis in onco-hematological patients

ObjectivesIn onco-hematological diseases, the incidence of paranasal sinuses infection dramatically increase and requires a combination of medical and surgical therapy. Balloon dilatation surgery (DS) is a minimally invasive, tissue preserving procedure. The study evaluates the results of DS for rhinosinusitis in immunocompromised patients.MethodsA retrospective chart review was conducted in 110 hematologic patients with rhinosinusitis. Twenty-five patients were treated with DS technique and 85 patients with endoscopic sinus surgery (ESS). We considered the type of anesthesia and the extent of intra- and postoperative bleeding. Patients underwent Sino-Nasal Outcome Test (SNOT-20) to evaluate changes in subjective symptoms and global patient assessment (GPA) questionnaire to value patient satisfaction.ResultsLocal anesthesia was employed in 8 cases of DS and in 15 of ESS. In 50 ESS patients, an anterior nasal packing was placed and in 12 cases a repacking was necessary. In the DS group, nasal packing was required in 8 cases and in 2 cases a repacking was placed (P=0.019 and P=0.422, respectively). The SNOT-20 change score showed significant improvement of health status in both groups. However the DS group showed a major improvement in 3 voices: need to blow nose, runny nose, and facial pain/pressure. The 3-month follow-up GPA questionnaire showed an higher satisfaction of DS group.ConclusionBalloon DS represents a potentially low aggressive treatment and appears to be relatively safe and effective in onco-hematologic patients. All these remarks may lead the surgeon to consider a larger number of candidates for surgical procedure