On the Spatial Coherence of Magnetic Ejecta: Measurements of Coronal Mass Ejections by Multiple Spacecraft Longitudinally Separated by 0.01 AU

Measurements of coronal mass ejections (CMEs) by multiple spacecraft at small radial separations but larger longitudinal separations is one of the ways to learn about the three-dimensional structure of CMEs. Here, we take advantage of the orbit of the Wind spacecraft that ventured to distances of up to 0.012 astronomical units (au) from the Sun-Earth line during the years 2000 to 2002. Combined with measurements from ACE, which is in a tight halo orbit around L1, the multipoint measurements allow us to investigate how the magnetic field inside magnetic ejecta (MEs) changes on scales of 0.005 - 0.012 au. We identify 21 CMEs measured by these two spacecraft for longitudinal separations of 0.007 au or more. We find that the time-shifted correlation between 30-minute averages of the non-radial magnetic field components measured at the two spacecraft is systematically above 0.97 when the separation is 0.008 au or less, but is on average 0.89 for greater separations. Overall, these newly analyzed measurements, combined with 14 additional ones when the spacecraft separation is smaller, point towards a scale length of longitudinal magnetic coherence inside MEs of 0.25 - 0.35 au for the magnitude of the magnetic field but 0.06 - 0.12 au for the magnetic field components. This finding raises questions about the very nature of MEs. It also highlights the need for additional "mesoscale" multi-point measurements of CMEs with longitudinal separations of 0.01 - 0.2 au.Comment: Published in ApJL, 6 page

Topical Issue in Solar Physics: Flux-rope Structure of Coronal Mass Ejections Preface

This Topical Issue of Solar Physics, devoted to the study of flux-rope structure in coronal mass ejections (CMEs), is based on two Coordinated Data Analysis Workshops (CDAWs) held in 2010 (20 - 23 September in Dan Diego, California, USA) and 2011 (September 5-9 in Alcala, Spain). The primary purpose of the CDAWs was to address the question: Do all CMEs have flux rope structure? There are 18 papers om this topical issue, including this preface.Comment: 4 page

FACTORES DE RIESGO RELACIONADOS CON DEPRESIÓN POSPARTO

El presente trabajo determinó factores de riesgo relacionados con la depresión post-parto en gestantes que asistieron al Hospital San Juan de Dios de Pamplona, durante el primer periodo académico del 2012. Para el logro de esta investigación se emplearon los principales conceptos teóricos de Cheril Tatano Back a través de la aplicación de instrumentos validados, tales como: Escala de Ansiedad, Depresión de Goldberg, Apgar familiar, Cuestionario de Apoyo social de Duke-UNC, Escala de Autoestima de Rosenberg, y la Escala de Depresión Postparto de Edimburgo a pacientes conscientes y orientados que accedieron voluntariamente a participar, gracias a esto se encontraron factores de riesgo que no fueron significativos para que las gestantes padeciesen depresión post-parto

FACTORES DE RIESGO PARA EMBARAZO EN ADOLESCENTES DE LOS ESTRATOS 1 Y 2 DE LA CIUDAD DE PAMPLONA NORTE DE SANTANDER DURANTE EL SEGUNDO PERIODO DE 2012

Objetivo: Identificar los Factores de Riesgo para embarazo en adolescentes de los estratos 1 y 2 de la cuidad de Pamplona, Norte de Santander, en el segundo periodo del año 2012. Materiales y métodos: En el periodo comprendido de septiembre a diciembre del año 2012, se realizó el presente estudio. Los casos fueron adolescentes primigestas con edades entre 14 y 19 años, de cualquier edad gestacional que asisten al control en un Hospital de la ciudad, mientras que los controles fueron adolescentes escolares de estratos 1 y 2 de la ciudad de Pamplona. El tamaño de la muestra calculado fue de 135 adolescentes con una relación caso-control de 1:2. Se calcularon los OR para obtener asociaciones con un IC al 95%; y se realizaron ajustes por edad. Resultados: Se encontró asociación entre el conocimiento de los métodos anticonceptivos y el uso de estos métodos como factor protector para el desarrollo de embarazo, no se encontró relación entre la edad en que la madre tuvo su primer hijo, la religión o el consumo de drogas, se realizo un ajuste por edad donde se encontró que independiente de la edad las personas que usan y conocen los métodos anticonceptivos disminuyen la posibilidad tener un embarazo. Conclusiones: El conocimiento y uso de los métodos anticonceptivos es un factor protector para el embarazo, lo que indica que se deben realizar estrategias para que los jóvenes conozcan estos métodos y así disminuir la cantidad de embarazos adolescentes

Two close binaries across the hydrogen-burning limit in the Praesepe open cluster

We present Keck I/OSIRIS and Keck II/NIRC2 adaptive optics imaging of two member candidates of the Praesepe stellar cluster (d=186.18$\pm$0.11 pc; 590-790 Myr), UGC J08451066+2148171 (L1.5$\pm$0.5) and UGCS J08301935$+$2003293 (no spectroscopic classification). We resolved UGCS J08451066$+$2148171 into a binary system in the near-infrared, with a $K$-band wavelength flux ratio of 0.89$\pm$0.04, a projected separation of 60.3$\pm$1.3 mas (11.2$\pm$0.7 au; 1$\sigma$). We also resolved UGCS J08301935$+$2003293 into a binary system with a flux ratio of 0.46$\pm$0.03 and a separation of 62.5$\pm$0.9 mas. Assuming zero eccentricity, we estimate minimum orbital periods of $\sim$100 years for both systems. According to theoretical evolutionary models, we derive masses in the range of 0.074-0.078 M$_{\odot}$ and 0.072-0.076 M$_{\odot}$ for the primary and secondary of UGCS J08451066$+$2148171 for an age of 700$\pm$100 Myr. In the case of UGCS J08301935$+$2003293, the primary is a low-mass star at the stellar/substellar boundary (0.070-0.078 M$_{\odot}$) while the companion candidate might be a brown dwarf (0.051-0.065 M$_{\odot}$). These are the first two binaries composed of L dwarfs in Praesepe. They are benchmark systems to derive the location of the substellar limit at the age and metallicity of Praesepe, determine the age of the cluster based on the lithium depletion boundary test, derive dynamical masses, and improve low-mass stellar and substellar evolutionary models at a well-known age and metallicity.Comment: 12 pages, 5 figures, 3 tables, accepted for publication in MNRA

Solar Energetic Particles Produced by a Slow Coronal Mass Ejection at ∼0.25 au

We present an analysis of Parker Solar Probe (PSP) IS⊙IS observations of ~30–300 keV n⁻¹ ions on 2018 November 11 when PSP was about 0.25 au from the Sun. Five hours before the onset of a solar energetic particle (SEP) event, a coronal mass ejection (CME) was observed by STEREO-A/COR2, which crossed PSP about a day later. No shock was observed locally at PSP, but the CME may have driven a weak shock earlier. The SEP event was dispersive, with higher energy ions arriving before the lower energy ones. Timing suggests the particles originated at the CME when it was at ~7.4R_⊙. SEP intensities increased gradually from their onset over a few hours, reaching a peak, and then decreased gradually before the CME arrived at PSP. The event was weak, having a very soft energy spectrum (−4 to −5 spectral index). The earliest arriving particles were anisotropic, moving outward from the Sun, but later, the distribution was observed to be more isotropic. We present numerical solutions of the Parker transport equation for the transport of 30–300 keV n⁻¹ ions assuming a source comoving with the CME. Our model agrees well with the observations. The SEP event is consistent with ion acceleration at a weak shock driven briefly by the CME close to the Sun, which later dissipated before arriving at PSP, followed by the transport of ions in the interplanetary magnetic field