The Thomson scattering cross section in a magnetized, high density plasma

We calculate the Thomson scattering cross section in a non-relativistic, magnetized, high density plasma -- in a regime where collective excitations can be described by magnetohydrodynamics. We show that, in addition to cyclotron resonances and an elastic peak, the cross section exhibits two pairs of peaks associated with slow and fast magnetosonic waves; by contrast, the cross section arising in pure hydrodynamics possesses just a single pair of Brillouin peaks. Both the position and the width of these magnetosonic-wave peaks depend on the ambient magnetic field and temperature, as well as transport and thermodynamic coefficients, and so can therefore serve as a diagnostic tool for plasma properties that are otherwise challenging to measure.Comment: Main paper: pp 1-8. Appendix: pp 8-10. 2 figure

First Case of Systemic Coronavirus Infection in a Domestic Ferret (Mustela putorius furo) in Peru.

A domestic ferret from Lima, Peru, died after ten days of non-specific clinical signs. Based on pathology, immunohistochemistry and molecular analysis, ferret systemic coronavirus (FRSCV)-associated disease was diagnosed for the first time in South America. This report highlights the potential spread of pathogens by the international pet trade

Constrained-Transport Magnetohydrodynamics with Adaptive-Mesh-Refinement in CHARM

We present the implementation of a three-dimensional, second order accurate Godunov-type algorithm for magneto-hydrodynamic (MHD), in the adaptive-mesh-refinement (AMR) cosmological code {\tt CHARM}. The algorithm is based on the full 12-solve spatially unsplit Corner-Transport-Upwind (CTU) scheme. The fluid quantities are cell-centered and are updated using the Piecewise-Parabolic-Method (PPM), while the magnetic field variables are face-centered and are evolved through application of the Stokes theorem on cell edges via a Constrained-Transport (CT) method. The multidimensional MHD source terms required in the predictor step for high-order accuracy are applied in a simplified form which reduces their complexity in three dimensions without loss of accuracy or robustness. The algorithm is implemented on an AMR framework which requires specific synchronization steps across refinement levels. These include face-centered restriction and prolongation operations and a {\it reflux-curl} operation, which maintains a solenoidal magnetic field across refinement boundaries. The code is tested against a large suite of test problems, including convergence tests in smooth flows, shock-tube tests, classical two- and three-dimensional MHD tests, a three-dimensional shock-cloud interaction problem and the formation of a cluster of galaxies in a fully cosmological context. The magnetic field divergence is shown to remain negligible throughout.Comment: 53 pages, 17 figs, under review by ApJ

Proton imaging of stochastic magnetic fields

Recent laser-plasma experiments report the existence of dynamically significant magnetic fields, whose statistical characterisation is essential for understanding the physical processes these experiments are attempting to investigate. In this paper, we show how a proton imaging diagnostic can be used to determine a range of relevant magnetic field statistics, including the magnetic-energy spectrum. To achieve this goal, we explore the properties of an analytic relation between a stochastic magnetic field and the image-flux distribution created upon imaging that field. We conclude that features of the beam's final image-flux distribution often display a universal character determined by a single, field-scale dependent parameter - the contrast parameter - which quantifies the relative size of the correlation length of the stochastic field, proton displacements due to magnetic deflections, and the image magnification. For stochastic magnetic fields, we establish the existence of four contrast regimes - linear, nonlinear injective, caustic and diffusive - under which proton-flux images relate to their parent fields in a qualitatively distinct manner. As a consequence, it is demonstrated that in the linear or nonlinear injective regimes, the path-integrated magnetic field experienced by the beam can be extracted uniquely, as can the magnetic-energy spectrum under a further statistical assumption of isotropy. This is no longer the case in the caustic or diffusive regimes. We also discuss complications to the contrast-regime characterisation arising for inhomogeneous, multi-scale stochastic fields, as well as limitations currently placed by experimental capabilities on extracting magnetic field statistics. The results presented in this paper provide a comprehensive description of proton images of stochastic magnetic fields, with applications for improved analysis of given proton-flux images.Comment: Main paper pp. 1-29; appendices pp. 30-84. 24 figures, 2 table

Follia e civiltà: Pope e l’ira di Achille

The essay investigates Alexander Pope's translation of Homer's Iliad, with special regard to his understanding of the idea of "menis", "anger", as martial madness. The essay focuses particularly on Pope's treatment of Achilles as a furious and raving soldier who eventually redeems himself through rational repentance. Achilles is seen as the prototype of the belligerent hero who societal rules compel to leave floor to the bureaucrat and civil servan

Correlators between Wilson loop and chiral operators in N=2 conformal gauge theories

We consider conformal N=2 super Yang-Mills theories with gauge group SU(N) and Nf=2N fundamental hypermultiplets in presence of a circular 1/2-BPS Wilson loop. It is natural to conjecture that the matrix model which describes the expectation value of this system also encodes the one-point functions of chiral scalar operators in presence of the Wilson loop. We obtain evidence of this conjecture by successfully comparing, at finite N and at the two-loop order, the one-point functions computed in field theory with the vacuum expectation values of the corresponding normal-ordered operators in the matrix model. For the part of these expressions with transcendentality zeta(3), we also obtain results in the large-N limit that are exact in the 't Hooft coupling lambda.Comment: 37 pages, 10 figures. v2: typo corrected, 3 references added. Version to appear on JHE

Open reduction and internal fixation combined with hinged elbow fixator in capitellum and trochlea fractures: a retrospective study of 15 patients followed for 29 months

Background and purpose The current surgical treatment for displaced fracture of the capitellum and trochlea is open reduction and internal fixation (ORIF), but the results are often unsatisfactory, particularly with complex fractures. Furthermore, the surgical approach, the kind of osteosynthesis, and postoperative management are controversial. We evaluated the results of internal fixation combined with hinged external fixation. Methods We analyzed 15 patients with a mean age of 47 (18-65) years. Based on the Bryan-Morrey-McKee classification, the fractures were identified as type I in 6 cases and type IV in 9. Active and passive motion was started and activities of daily living were permitted on the second postoperative day. The mean follow-up time was 29 (12-49) months. Results In 13 cases, functional range of motion was obtained within 6 weeks of surgery. At final follow-up, 14 patients had a stable, pain-free elbow with a mean active range of motion of 13° to 140°. The average score on the Mayo elbow performance score was 98. Interpretation The use of the hinged fixator allows early motion of the elbow while preserving joint stability. It may have additional value in complex articular fractures when stable internal fixation cannot be obtained with ORIF, and in the presence of severe ligamentous injuries

Foreign Bodies Causing Asphyxiation in Children: The Experience of the Buenos Aires Paediatric ORL Clinic

Inhalation or aspiration of a foreign body (FB) occurs relatively frequently in young children. The size, shape, type and site of arrest of the FB lead to variability in the clinical picture. The present study included data from 65 cases of FB inhalation presenting over 1 year at the Children's Hospital Gutierrez, Buenos Aires, Argentina, compared with information from four well-known published case series chosen as representative of other cultural and geographical backgrounds: the USA, Europe, North Africa (Egypt) and Asia (India). The mean age of children studied was 4.03 years. Injuries happened mainly at home (53 cases [81.54%]) and under adult supervision (59 cases [90.77%]). The most frequently inhaled FB was nuts, however, in contrast to previous reports, the majority of incidents involved inhalation of an inorganic, rather than an organic (food) FB. Complications included pneumonia (three cases), atelectasis (two cases) and pneumonitis (one case). No deaths were recorded. These data suggest that children play with objects inappropriate for their age, such as pins and nails, that adults may not be aware of the choking risks, and that more effort is required in educating caregivers about these risks

Plastic Deformation in Laser-Induced Shock Compression of Monocrystalline Copper

Copper monocrystals were subjected to shock compression at pressures of 10–60 GPa by a short (3 ns initial) duration laser pulse. Transmission electron microscopy revealed features consistent with previous observations of shock-compressed copper, albeit at pulse durations in the µs regime. The results suggest that the defect structure is generated at the shock front. A mechanism for dislocation generation is presented, providing a realistic prediction of dislocation density as a function of pressure. The threshold stress for deformation twinning in shock compression is calculated from the constitutive equations for slip, twinning, and the Swegle-Grady relationship