692 research outputs found
The LHC Logging Service : Handling terabytes of on-line data
Based on previous experience with LEP, a long-term data logging service for the LHC was developed and put in place in 2003, several years before beam operation. The scope of the logging service covers the evolution over time of data acquisitions on accelerator equipment and beam related parameters. The intention is to keep all this time-series data on-line for the lifetime of LHC, allowing easy data comparisons with previous years. The LHC hardware commissioning has used this service extensively prior to the first beams in 2008 and even more so in 2009. Current data writing rates exceed 15TB/year and continue to increase. The high data volumes and throughput rates, in writing as well as in reading, require special arrangements on data organization and data access methods
Deflection and Rotation of CMEs from Active Region 11158
Between the 13 and 16 of February 2011 a series of coronal mass ejections
(CMEs) erupted from multiple polarity inversion lines within active region
11158. For seven of these CMEs we use the Graduated Cylindrical Shell (GCS)
flux rope model to determine the CME trajectory using both Solar Terrestrial
Relations Observatory (STEREO) extreme ultraviolet (EUV) and coronagraph
images. We then use the Forecasting a CME's Altered Trajectory (ForeCAT) model
for nonradial CME dynamics driven by magnetic forces, to simulate the
deflection and rotation of the seven CMEs. We find good agreement between the
ForeCAT results and the reconstructed CME positions and orientations. The CME
deflections range in magnitude between 10 degrees and 30 degrees. All CMEs
deflect to the north but we find variations in the direction of the
longitudinal deflection. The rotations range between 5\mydeg and 50\mydeg with
both clockwise and counterclockwise rotations occurring. Three of the CMEs
begin with initial positions within 2 degrees of one another. These three CMEs
all deflect primarily northward, with some minor eastward deflection, and
rotate counterclockwise. Their final positions and orientations, however,
respectively differ by 20 degrees and 30 degrees. This variation in deflection
and rotation results from differences in the CME expansion and radial
propagation close to the Sun, as well as the CME mass. Ultimately, only one of
these seven CMEs yielded discernible in situ signatures near Earth, despite the
active region facing near Earth throughout the eruptions. We suggest that the
differences in the deflection and rotation of the CMEs can explain whether each
CME impacted or missed the Earth.Comment: 18 pages, 6 figures, accepted in Solar Physic
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
Dynamic model of wind energy conversion systems with variable speed synchronous generator and full-size power converter for large-scale power system stability studies
Se inscribe dentro de la línea de investigación de Integración en red de sistemas eólicos. Se presenta un modelo informático en plataforma PSS/E para sistemas de generación eólica de velocidad variable del tipo Síncrono con Convertidor de plena potencia, capaz de simular el comportamuiento dinámico de estos sistemas en estudios de estabilidad del sistema eléctric
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=186.180.11 pc;
590-790 Myr), UGC J08451066+2148171 (L1.50.5) and UGCS J083019352003293
(no spectroscopic classification). We resolved UGCS J084510662148171 into a
binary system in the near-infrared, with a -band wavelength flux ratio of
0.890.04, a projected separation of 60.31.3 mas (11.20.7 au;
1). We also resolved UGCS J083019352003293 into a binary system with
a flux ratio of 0.460.03 and a separation of 62.50.9 mas. Assuming
zero eccentricity, we estimate minimum orbital periods of 100 years for
both systems. According to theoretical evolutionary models, we derive masses in
the range of 0.074-0.078 M and 0.072-0.076 M for the
primary and secondary of UGCS J084510662148171 for an age of 700100
Myr. In the case of UGCS J083019352003293, the primary is a low-mass star at
the stellar/substellar boundary (0.070-0.078 M) while the companion
candidate might be a brown dwarf (0.051-0.065 M). 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
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