Brans-Dicke geometry

We reveal the non-metric geometry underlying omega-->0 Brans-Dicke theory by unifying the metric and scalar field into a single geometric structure. Taking this structure seriously as the geometry to which matter universally couples, we show that the theory is fully consistent with solar system tests. This is in striking constrast with the standard metric coupling, which grossly violates post-Newtonian experimental constraints.Comment: 8 pages, v2 with additional comment and reference

Geometry for the accelerating universe

The Lorentzian spacetime metric is replaced by an area metric which naturally emerges as a generalized geometry in quantum string and gauge theory. Employing the area metric curvature scalar, the gravitational Einstein-Hilbert action is re-interpreted as dynamics for an area metric. Without the need for dark energy or fine-tuning, area metric cosmology explains the observed small acceleration of the late Universe.Comment: 4 pages, 1 figur

Monitoring Social Media to Identify Environmental Crimes through NLP - A Preliminary Study

This paper presents the results of research carried out on the UNIOR Eye corpus, a corpus which has been built by downloading tweets related to environmental crimes. The corpus is made up of 228,412 tweets organized into four different subsections, each one concerning a specific environmental crime. For the current study we focused on the subsection of waste crimes, composed of 86,206 tweets which were tagged according to the two labels alert and no alert. The aim is to build a model able to detect which class a tweet belongs to

Massive motion in Brans-Dicke geometry and beyond

Gravity theories that can be viewed as dynamics for area metric manifolds, for which Brans-Dicke theory presents a recently studied example, require for their physical interpretation the identification of the distinguished curves that serve as the trajectories of light and massive matter. Complementing previous results on the propagation of light, we study effective massive point particle motion. We show that the relevant geometrical structure is a special Finsler norm determined by the area metric, and that massive point particles follow Finsler geodesics.Comment: 12 page

Geometry and stability of dynamical systems

We reconsider both the global and local stability of solutions of continuously evolving dynamical systems from a geometric perspective. We clarify that an unambiguous definition of stability generally requires the choice of additional geometric structure that is not intrinsic to the dynamical system itself. While global Lyapunov stability is based on the choice of seminorms on the vector bundle of perturbations, we propose a definition of local stability based on the choice of a linear connection. We show how this definition reproduces known stability criteria for second order dynamical systems. In contrast to the general case, the special geometry of Lagrangian systems provides completely intrinsic notions of global and local stability. We demonstrate that these do not suffer from the limitations occurring in the analysis of the Maupertuis-Jacobi geodesics associated to natural Lagrangian systems.Comment: 22 pages, 2 figure

Psoriatic arthritis: epidemiological and clinical aspects in a cohort of 1.306 italian patients

Because there is the impression that psoriatic arthritis is a composite disorder with mild forms close to more severe and aggressive ones, we conducted a multicenter study with the aim of characterizing disease expression in a large cohort of Italian patients. One-thousand-three-hundred-six patients fulfilled inclusion criteria and were analyzed in this study. Psoriasis antedated the onset of arthritis in the majority of the cases (67.7%). More rare was inverse or simultaneous onset which occurred in 17.3% and 15.0% of the cases, respectively. Peripheral articular involvement (mono-oligo or polyarthritis) was recorded in 88.7% of the cases while spondylitis occurred in 11.3%. Peripheral enthesopathies were found in 28.1% of the cases with a marked occurrence in patients with axial involvement (64.5% vs 35.5% in oligo or polyarthritis). Abnormal levels of ESR and CRP respectively occurred in 52.2% and in 52.6% of the cases, while rheumatoid factor was detected in 5.0% of the cases. On the basis of distribution of joint involvement, symmetry and presence of peripheral enthesopathies we recognized three clusters of arthritis. Patients included in Cluster 1 and Cluster 2 showed a severe form of polyarthritis in most of the cases (82.9%), with increased serum levels of inflammatory indices in more than 85% of the cases. Almost all the hospitalized patients (97.1%) were included in this two clusters. They markedly assumed steroids and methotrexate or another DMARD. About half of the patients (51.1%) included in Cluster 3 showed mono-oligo articular involvement. Serum inflammatory indices were increased in 20.8% of the cases while hospitalization occurred only in 2.9% of the cases and NSAIDs were the treatment of choice. The evidence in our country of a large prevalence of severe forms of arthritis needing specific and aggressive approach outlines the requirement of an intense educational action aimed at increasing the awareness of this condition

Area metric gravity and accelerating cosmology

Area metric manifolds emerge as effective classical backgrounds in quantum string theory and quantum gauge theory, and present a true generalization of metric geometry. Here, we consider area metric manifolds in their own right, and develop in detail the foundations of area metric differential geometry. Based on the construction of an area metric curvature scalar, which reduces in the metric-induced case to the Ricci scalar, we re-interpret the Einstein-Hilbert action as dynamics for an area metric spacetime. In contrast to modifications of general relativity based on metric geometry, no continuous deformation scale needs to be introduced; the extension to area geometry is purely structural and thus rigid. We present an intriguing prediction of area metric gravity: without dark energy or fine-tuning, the late universe exhibits a small acceleration.Comment: 52 pages, 1 figure, companion paper to hep-th/061213

Propagation of light in area metric backgrounds

The propagation of light in area metric spacetimes, which naturally emerge as refined backgrounds in quantum electrodynamics and quantum gravity, is studied from first principles. In the geometric-optical limit, light rays are found to follow geodesics in a Finslerian geometry, with the Finsler norm being determined by the area metric tensor. Based on this result, and an understanding of the non-linear relation between ray vectors and wave covectors in such refined backgrounds, we study light deflection in spherically symmetric situations, and obtain experimental bounds on the non-metricity of spacetime in the solar system.Comment: 18pp, no figures, Journal versio