Strong-field gravitational-wave emission in Schwarzschild and Kerr geometries: some general considerations

We show how the concurrent implementation of the exact solutions of the Einstein equations, of the equations of motion of the test particles, and of the relativistic estimate of the emission of gravitational waves from test particles, can establish a priori constraints on the possible phenomena occurring in Nature. Two examples of test particles starting at infinite distance or from finite distance in a circular orbit around a Kerr black hole are considered: the first leads to a well defined gravitational wave burst the second to a smooth merging into the black hole. This analysis is necessary for the study of the waveforms in merging binary systems.Comment: Resubmitted to PRD after Referee repor

Healthcare is the most breached industry : how do we change that?

Healthcare is the most breached industry in the United States. Health records are now fetching more money on the black market than credit card numbers. Threats to Healthcare data security come from criminal hackers, hacktivists, state-sponsored hackers, malicious employees with perhaps the greatest threat coming from accidental or negligent disclosure by employees. Most information security related investments are driven by the need to meet Health Insurance Portability and Accountability Act (HIPAA) requirements. Typically, these investments are characterized by heavy reliance on technology, outsourcing security activities, and risk transfer (Cyber Liability Policy). As a result of this compliance focused security spending, little headway is made in reducing the number of breaches in healthcare. Two important weaknesses that will continue to inhibit progress in protecting health information are: the industry lacks a culture of security, and there is a lack of strong leadership among those tasked with overseeing information security.Informatio

Analysis of a chemo-repulsion model with nonlinear production: The continuous problem and unconditionally energy stable fully discrete schemes

We consider the following repulsive-productive chemotaxis model: Let $p\in (1,2)$, find $u \geq 0$, the cell density, and $v \geq 0$, the chemical concentration, satisfying \begin{equation}\label{C5:Am} \left\{ \begin{array} [c]{lll} \partial_t u - \Delta u - \nabla\cdot (u\nabla v)=0 \ \ \mbox{in}\ \Omega,\ t>0,\\ \partial_t v - \Delta v + v = u^p \ \ \mbox{in}\ \Omega,\ t>0, \end{array} \right. \end{equation} in a bounded domain $\Omega\subseteq \mathbb{R}^d$, $d=2,3$. By using a regularization technique, we prove the existence of solutions of this problem. Moreover, we propose three fully discrete Finite Element (FE) nonlinear approximations, where the first one is defined in the variables $(u,v)$, and the second and third ones by introducing ${\boldsymbol\sigma}=\nabla v$ as an auxiliary variable. We prove some unconditional properties such as mass-conservation, energy-stability and solvability of the schemes. Finally, we compare the behavior of the schemes throughout several numerical simulations and give some conclusions.Comment: arXiv admin note: substantial text overlap with arXiv:1807.0111

Luxación congénita de cadera: nuestra experiencia

La luxación congénita de cadera (L.C.C.) representa, aún hoy día, un auténtico problema dentro de la ortopedia infantil por su frecuencia y sobre todo por las secuelas invalidantes que un diagnóstico tardío puede condicionar. Basados en nuestra experiencia y revisión de un total de 334 casos, exponemos y valoramos los resultados obtenidos y propugnamos una íntima colaboración entre tocólogos, pediatras y ortopedas para evitar que la displasia luxante del recién nacido se transforme en una verdadera luxación del niño que ya ha comenzado a caminar. Ante la luxación ya establecida rechazamos cualquier intento de reducción forzada bajo anestesia general e inmovilización en yesos sucesivos de Lorenz, y proponemos una metodología basada en la reducción lenta por tracción continua en abducción progresiva, artrografía, limbectomía si fuese necesaria y posterior osteotomía desrotadora subtrocantérea, a veces con varización. Por encima de los 4 años pueden ser necesarias las acetabuloplastias.Congenital hip dislocation represents, even today, an authenti c problem within the pediatric orthopaedic field due to its frequency, and above all, becaus e of the negative results of a late diagnosis. Based on our experience and review of a total of 334 cases, they must recommend based on those cases an increased colaboration between Tocologists, Pediatricians and Ortopedics to avoid that displasia dislocation in newborns become s a true dislocation in a child that has begun to walk. Unde r established cases of dislocation, they are against the forced reduction unde r general anesthesia and succesive-continued inmovilization with Lorenz Casts. They recommend treatment based on slow reduction by continous captive traction, arthrography, if necessary limbectonomy with posterior. De-Rotational subtrochanteric osteotomy, sometimes Varus-Producing. For children 4 year s or older acetabuloplasty may be necessary