General existence proof for rest frame systems in asymptotically flat space-time

We report a new result on the nice section construction used in the definition of rest frame systems in general relativity. This construction is needed in the study of non trivial gravitational radiating systems. We prove existence, regularity and non-self-crossing property of solutions of the nice section equation for general asymptotically flat space times. This proves a conjecture enunciated in a previous work.Comment: 14 pages, no figures, LaTeX 2

On computations of angular momentum and its flux in numerical relativity

The purpose of this note is to point out ambiguities that appear in the calculation of angular momentum and its radiated counterpart when some simple formulae are used to compute them. We illustrate, in two simple different examples, how incorrect results can be obtained with them. Additionally, we discuss the magnitude of possible errors in well known situations.Comment: 8 pages. Minor improvements . To appear in Class. Quantum Gra

The Goldberg-Sachs theorem in linearized gravity

The Goldberg-Sachs theorem has been very useful in constructing algebraically special exact solutions of Einstein vacuum equation. Most of the physical meaningful vacuum exact solutions are algebraically special. We show that the Goldberg-Sachs theorem is not true in linearized gravity. This is a remarkable result, which gives light on the understanding of the physical meaning of the linearized solutions.Comment: 6 pages, no figures, LaTeX 2

Gravitational lens optical scalars in terms of energy-momentum distributions

This is a general work on gravitational lensing. We present new expressions for the optical scalars and the deflection angle in terms of the energy-momentum tensor components of matter distributions. Our work generalizes standard references in the literature where normally stringent assumptions are made on the sources. The new expressions are manifestly gauge invariant, since they are presented in terms of curvature components. We also present a method of approximation for solving the lens equations, that can be applied to any order.Comment: 17 pages, 2 figures. Titled changed. Small improvements. References added. Final version published in Phys.Rev.

Spin and Center of Mass in Axially Symmetric Einstein-Maxwell Spacetimes

We give a definition and derive the equations of motion for the center of mass and angular momentum of an axially symmetric, isolated system that emits gravitational and electromagnetic radiation. A central feature of this formulation is the use of Newman-Unti cuts at null infinity that are generated by worldlines of the spacetime. We analyze some consequences of the results and comment on the generalization of this work to general asymptotically flat spacetimes.Comment: 20 page

The PKU & ME study: A qualitative exploration, through co-creative sessions, of attitudes and experience of the disease among adults with phenylketonuria in Italy

Background: Phenylketonuria (PKU) is a hereditary metabolic disease that can be diagnosed and successfully treated from birth with a lifelong phenylalanine-restricted dietary regimen. However, optimal adherence to diet remains an issue and often progressively decreases after adolescence. The study aimed to explore the experience of adults living with PKU in order to gain insights related to their adherence to diet and engagement in managing their condition. Methods: The study adopted a qualitative methodology in sessions that combined specifically designed co- creation exercises with focus group discussion. Adults with early-treated classic PKU were enrolled for 2 different sessions - one for adherent and one for non-adherent patients. The verbatim notes of both sessions and focus group were analyzed using content analysis. Results: Twelve adherent and nine non-adherent adults with PKU participated. Besides the behavioral dictates of following a strict diet, adherent adults reported a positive mental approach and organizational rigor; they seemed aware of the consequences of high-phenylalanine levels, reporting that it can affect mood and conse- quently social interactions which they value highly. In the non-adherent group, the individuals seemed to not fully accept their disease: they were aware of the consequences of non-adherence in children but not in adults, they felt the management of PKU was an individual burden and they experienced a feeling of \u2018diversity\u2019 in the social context (related to eating) that caused emotional distress. PKU seemed a very influential element of the identity both for adherent and non-adherent adults, but with different consequences for the two groups. Finally, all participants reported the desire to be assisted in a healthcare setting dedicated to adults. Conclusions: The findings expand the understanding of the psychological experience of adult patients with PKU in relation to their disease and its dietary requirements, highlighting specific factors that might drive tailored educational or psychological intervention to improve adherence and engagement in the care process

Smooth null hypersurfaces near the horizon in the presence of tails

We show that the power-law decay modes found in linear perturbations of Schwarzschild black holes, generally called tails, do not produce caustics on a naturally defined family of null surfaces in the neighborhood of i+ of a black hole horizon

Intrinsic angular momentum for radiating spacetimes which agrees with the Komar integral in the axisymmetric case

Here, we present a new definition of intrinsic angular momentum at future null infinity, based on the charge-integral approach. This definition is suitable for the general case of radiating spacetimes without symmetries, which does not suffer from supertranslation ambiguities. In the case of axial symmetry, this new definition agrees with the Komar integral.publishedVersionFil: Gallo, Emanuel. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina.Fil: Gallo, Emanuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Física Enrique Gaviola; Argentina.Fil: Moreschi, Osvaldo Mario. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina.Fil: Moreschi, Osvaldo Mario. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Física Enrique Gaviola; Argentina.Física de Partículas y Campo

Determinants of surgeon choice in cases of suspected implant rupture following mastectomy or aesthetic breast surgery: Clinical implications

Implant ruptures may be diagnosed by physical examination, ultrasound (US), and magnetic resonance imaging (MRI). The absence of standard guidelines to approach to implant ruptures may cause unnecessary surgical revisions in the absence of radiological confirmation of prosthetic damages.The purpose of this study was to analyze the diagnostic procedures applied to patients with suspected prosthetic rupture and surgeon choices to perform a revision or to plan a clinical and radiological follow-up.We conducted a retrospective study on 62 women submitted to revision surgery due to radiological diagnosis of suspected implant rupture, following mastectomy or aesthetic reconstruction, and admitted to a Plastic Surgery Department between 2008 and 2018.Seventy-three implants, believed to be ruptured, were explanted. One-third of these were intact and unnecessarily explanted. US associated with MRI evaluation resulted in the most helpful diagnostical method.A standardized clinical and radiological approach is essential to manage breast implant ruptures successfully. An innovative protocol is proposed in order to: ensure the appropriate management of implant ruptures and prevent unnecessary surgical revisions; reduce the risk of claims for medical malpractice in cases of unsatisfactory final aesthetic results or worse than before