Cosmic rays from trans-relativistic supernovae

We derive constraints that must be satisfied by the sources of ~10^{15} to ~10^{18} eV cosmic rays, under the assumption that the sources are Galactic. We show that while these constraints are not satisfied by ordinary supernovae (SNe), which are believed to be the sources of <10^{15} eV cosmic rays, they may be satisfied by the recently discovered class of trans-relativistic supernovae (TRSNe), which were observed in association with gamma-ray bursts. We define TRSNe as SNe that deposit a large fraction, f_R>10^{-2}, of their kinetic energy in mildly relativistic, \gamma\beta>1, ejecta. The high velocity ejecta enable particle acceleration to ~10^{18} eV, and the large value of f_R (compared to f_R~10^{-7} for ordinary SNe) ensures that if TRSNe produce the observed ~10^{18} eV cosmic ray flux, they do not overproduce the flux at lower energies. This, combined with the estimated rate and energy production of TRSNe, imply that Galactic TRSNe may be the sources of cosmic rays with energies up to ~10^{18}eV .Comment: Accepted to ApJ. Expanded abstract, introduction, discussio

Magnetic field dissipation in neutron star crusts: from magnetars to isolated neutron stars

We study the non--linear evolution of magnetic fields in neutron star crusts with special attention to the influence of the Hall drift. Our goal is to understand the conditions for fast dissipation due to the Hall term in the induction equation. We study the interplay of Ohmic dissipation and Hall drift in order to find a timescale for the overall crustal field decay. We solve numerically the Hall induction equation by means of a hybrid method (spectral in angles but finite differences in the radial coordinate). The microphysical input consists of the most modern available crustal equation of state, composition and electrical conductivities. We present the first long term simulations of the non--linear magnetic field evolution in realistic neutron star crusts with a stratified electron number density and temperature dependent conductivity. We show that Hall drift influenced Ohmic dissipation takes place in neutron star crusts on a timescale of 1 Myr. When the initial magnetic field has magnetar strength, the fast Hall drift results in an initial rapid dissipation stage that lasts 10-50 kyr. The interplay of the Hall drift with the temporal variation and spatial gradient of conductivity tends to favor the displacement of toroidal fields toward the inner crust, where stable configurations can last for 1 Myr. We show that the thermally emitting isolated neutron stars, as the Magnificent Seven, are very likely descendants of neutron stars born as magnetars.Comment: 14 pages, 10 figure

Applying logic to pulmonary artery catheter use

Mansour and colleagues recommend not routinely using the pulmonary artery catheter to guide hemodynamic management in the intensive care unit, because the perceived benefits are largely intangible [1]. Pulmonary artery catheter monitoring of the right ventricular ejection fraction (RVef) and of the right ventricular end-diastolic volume (EDV), however, reflects powerful yet underutilized relationships that assess right ventricular performance. Since the cardiac output equals the product of the RVef, the EDV and the heart rate, one can assess the RVef to EDV relations as direct measures of right ventricular performance. A series of RVef, EDV and heart rate combinations can give the same cardiac output (Figure 1); monitoring or targeting cardiac output alone ignores this reality. For example, in hypovolemia the EDV is low and the RVef is increased

Crashdynamics with DYNA3D: Capabilities and research directions

The application of the explicit nonlinear finite element analysis code DYNA3D to crashworthiness problems is discussed. Emphasized in the first part of this work are the most important capabilities of an explicit code for crashworthiness analyses. The areas with significant research promise for the computational simulation of crash events are then addressed

International connections within the national government : Brazilian public legal careers and international circulation (2008–2018)

Taking into account the relation between the international circulation of legal elites and the legitimization of institutional models in Brazil, this study comparatively analyzes international leaves of three categories of legal careers between 2008 and 2018: Federal prosecutors, attorneys for Brazil and federal agencies, and federal commissioners. Analysis of the international destinations of these categories al lowed us to identify associations established with foreign agencies that disseminate different models of law and contribute to the reinforcement of autonomous corporations in the national space. Our data is built from the mapping of cooperation networks that connect Brazilian prosecutors, attorneys for Brazil and federal agencies, and commissioners with their counterparts in the United States and in international organizations. These connections have contributed to the strengthening of apolitical protagonism of these categories in the Brazilian legal space in recent decades