Fast and optimal solution to the Rankine-Hugoniot problem

A new, definitive, reliable and fast iterative method is described for determining the geometrical properties of a shock (i.e., theta sub Bn, yields N, V sub s and M sub A), the conservation constants and the self-consistent asymptotic magnetofluid variables, that uses the three dimensional magnetic field and plasma observations. The method is well conditioned and reliable at all theta sub Bn angles regardless of the shock strength or geometry. Explicit proof of uniqueness of the shock geometry solution by either analytical or graphical methods is given. The method is applied to synthetic and real shocks, including a bow shock event and the results are then compared with those determined by preaveraging methods and other iterative schemes. A complete analysis of the confidence region and error bounds of the solution is also presented

The inner edge of the plasma sheet and the diffuse aurora

Three dimensional measurements from the ISEE-1 low energy electron spectrometer are used to map the location of the inner edge of the plasma sheet and study the anisotropies in the electron distribution function associated with this boundary. Lower energy plasma sheet electrons have inner edges closer to the Earth than higher energies with the separations at different energies being larger near dawn and after dusk than at midnight. Lowest energy inner edges are frequently located adjacent to the plasmapause in the dawn hemisphere but are often separated from it in the dusk hemisphere by a gap of at least several Re. The energy dispersion is minimal in the afternoon quadrant where the inner edge is near the magnetopause and frequently oscillating on a time scale of minutes. The location of the inner edge is probably determined primarily by the motion of electrons in the existing electric and magnetic fields rather than by strong diffusion as has sometimes been supposed

Access to diagnosis and treatment of Chagas disease/infection in endemic and non-endemic countries in the XXI century.

In this article, Médicos Sin Fronteras (MSF) Spain faces the challenge of selecting, piecing together, and conveying in the clearest possible way, the main lessons learnt over the course of the last seven years in the world of medical care for Chagas disease. More than two thousand children under the age of 14 have been treated; the majority of whom come from rural Latin American areas with difficult access. It is based on these lessons learnt, through mistakes and successes, that MSF advocates that medical care for patients with Chagas disease be a reality, in a manner which is inclusive (not exclusive), integrated (with medical, psychological, social, and educational components), and in which the patient is actively followed. This must be a multi-disease approach with permanent quality controls in place based on primary health care (PHC). Rapid diagnostic tests and new medications should be available, as well as therapeutic plans and patient management (including side effects) with standardised flows for medical care for patients within PHC in relation to secondary and tertiary level, inclusive of epidemiological surveillance systems

Educación Inclusiva del Alumnado Inmigrante: Lecciones desde Estados Unidos, Canadá y Australia

Muchos programas, en España o Europa, entienden al alumnado inmigrante como un colectivo homogéneo, aplicando soluciones iguales a todos, sin lograr promover su inclusión socio-educativa. Sin embargo, algunos países anglosajones observan diferencias en este grupo que influyen en su éxito educativo e inclusión social y cuyo conocimiento puede ayudar a promover actuaciones que atiendan mejor a esta población. El artículo describe y analiza el concepto de estudiante con escolaridad formal limitada o interrumpida y discute los factores que la escuela tiene en cuenta para fomentar su inclusión socio-educativa, abogando por una intervención holística que tenga en cuenta este alumnado necesita mucho más que centrar su aprendizaje únicamente el nuevo idioma, por ejemplo el apoyo social para superar los problemas socioemocionales que les acompañan. Resulta especialmente relevante para España y Europa, pues recientemente acuden cada vez más alumnos con estas características a nuestras escuelas. Many programs, in Spain or Europe, understand immigrant students as a homogeneous group, applying equal solutions to all, without being able to promote their socio-educational inclusion. However, some Anglophone countries observe differences within this group that may influence their educational success and social inclusion and whose knowledge can help to promote actions that better serve this population. The article describes and analyzes the concept of a student with limited or interrupted formal education and discusses the factors that schools may consider for promoting their socio-educational inclusion, advocating a holistic intervention that takes into account this students' needs which go beyond focusing their learning only on the new language, for example social support to overcome the socio-emotional problems that accompany them. It is especially relevant for Spain and Europe, as more and more students with these characteristics are arriving to our schools

Personalized Optical Designs and Manipulating Optics: Applications on the Anterior Segment of the Eye

The image-forming properties of the eye can be described in terms of wave aberration. Understanding the link between aberrations and the anterior segment geometry is therefore of crucial importance for (i) comprehending how the eye works, (ii) modelling the optics of individual eyes, (iii) optimizing optical solutions, or (iv) designing surgical strategies. The eye has many innate adaptations that minimize optical aberrations. In most normal young eyes, the magnitude of aberrations of the cornea is significantly larger than for the whole eye, indicating a significant role of the crystalline lens in compensating corneal aberrations. However, due to geometrical and structural changes, this ocular compensation gets disturbed in different anterior segment conditions, such as keratoconus, presbyopia, or cataract. Keratoconus progressively degrades the corneal shape and, consequently, vision in the adolescence, with a prevalence of 0.05% in the general population. Meanwhile, presbyopia and cataract are conditions related to aging that affect the structure of the crystalline lens, one referring to a loss in accommodative amplitude (presbyopia) and the other to a progressive loss of transparency (cataract). Presbyopia affects 100% of the population older than 45¿years of age, ..

The First in situ Observation of Kelvin-Helmholtz Waves at High-Latitude Magnetopause during Strongly Dawnward Interplanetary Magnetic Field Conditions

We report the first in situ observation of high-latitude magnetopause (near the northern duskward cusp) Kelvin-Helmholtz waves (KHW) by Cluster on January 12, 2003, under strongly dawnward interplanetary magnetic field (IMF) conditions. The fluctuations unstable to Kelvin-Helmholtz instability (KHI) are found to propagate mostly tailward, i.e., along the direction almost 90 deg. to both the magnetosheath and geomagnetic fields, which lowers the threshold of the KHI. The magnetic configuration across the boundary layer near the northern duskward cusp region during dawnward IMF is similar to that in the low-latitude boundary layer under northward IMF, in that (1) both magnetosheath and magnetospheric fields across the local boundary layer constitute the lowest magnetic shear and (2) the tailward propagation of the KHW is perpendicular to both fields. Approximately 3-hour-long periods of the KHW during dawnward IMF are followed by the rapid expansion of the dayside magnetosphere associated with the passage of an IMF discontinuity that characterizes an abrupt change in IMF cone angle, Phi = acos (B(sub x) / absolute value of Beta), from approx. 90 to approx. 10. Cluster, which was on its outbound trajectory, continued observing the boundary waves at the northern evening-side magnetopause during sunward IMF conditions following the passage of the IMF discontinuity. By comparing the signatures of boundary fluctuations before and after the IMF discontinuity, we report that the frequencies of the most unstable KH modes increased after the discontinuity passed. This result demonstrates that differences in IMF orientations (especially in f) are associated with the properties of KHW at the high-latitude magnetopause due to variations in thickness of the boundary layer, and/or width of the KH-unstable band on the surface of the dayside magnetopause

Acceleration of Solar Wind Ions by Nearby Interplanetary Shocks: Comparison of Monte Carlo Simulations with Ulysses Observations

The most stringent test of theoretical models of the first-order Fermi mechanism at collisionless astrophysical shocks is a comparison of the theoretical predictions with observational data on particle populations. Such comparisons have yielded good agreement between observations at the quasi-parallel portion of the Earth's bow shock and three theoretical approaches, including Monte Carlo kinetic simulations. This paper extends such model testing to the realm of oblique interplanetary shocks: here observations of proton and alpha particle distributions made by the SWICS ion mass spectrometer on Ulysses at nearby interplanetary shocks are compared with test particle Monte Carlo simulation predictions of accelerated populations. The plasma parameters used in the simulation are obtained from measurements of solar wind particles and the magnetic field upstream of individual shocks. Good agreement between downstream spectral measurements and the simulation predictions are obtained for two shocks by allowing the the ratio of the mean-free scattering length to the ionic gyroradius, to vary in an optimization of the fit to the data. Generally small values of this ratio are obtained, corresponding to the case of strong scattering. The acceleration process appears to be roughly independent of the mass or charge of the species.Comment: 26 pages, 6 figures, AASTeX format, to appear in the Astrophysical Journal, February 20, 199