207 research outputs found
Adicción al deporte: el peligro de la sobredosis de ejercicio
La práctica deportiva forma parte del estilo de vida de los seres humanos postmodernos, pudiendo convertirse en una obsesión cuando su uso es excesivo, continuo, constante e intenso, pudiendo dar lugar a la adicción o dependencia al ejercicio. Actualmente son pocos los estudios e investigaciones hechos al respecto, por ello nuestro objetivo es analizar el estado de la cuestión, sus características psicológicas y psicopatológicas, y elaborar un cuestionario que permita evaluar la adicción al ejercicio, así como establecer su fiabilidad y validez para su detección y manejo clínico. Tras la elaboración del cuestionario, SAS, hemos pretendido observar cómo se manifiesta la adicción a nivel físico, psicológico y social. En este artículo presentamos los primeros resultados analizados tras un estudio exploratorio piloto a una muestra pequeña, N=33, compuesta por 16 mujeres y 17 hombres, que contestaron de forma voluntaria el cuestionario, compuesto por 40 ítems sencillos de respuesta dicotómica, (NO; SI). Aunque es una muestra limitada, la fiabilidad de dicho cuestionario es buena, con un Alpha de Cronbach superior a 0.8. Algunos de los enunciados del mismo han resultado ser muy específicos para la detección de la adicción, y asimismo, la edad y las horas dedicadas a la práctica de ejercicio físico tienen especial relevancia. Como conclusión se propone la primera escala española (SAS) para la detección de la adicción o dependencia al deporte, cuya fiabilidad y validez será analizada en estudios posteriores
Isotopic Composition of Light Nuclei in Cosmic Rays: Results from AMS-01
The variety of isotopes in cosmic rays allows us to study different aspects
of the processes that cosmic rays undergo between the time they are produced
and the time of their arrival in the heliosphere. In this paper we present
measurements of the isotopic ratios 2H/4He, 3He/4He, 6Li/7Li, 7Be/(9Be+10Be)
and 10B/11B in the range 0.2-1.4 GeV of kinetic energy per nucleon. The
measurements are based on the data collected by the Alpha Magnetic
Spectrometer, AMS-01, during the STS-91 flight in 1998 June.Comment: To appear in ApJ. 12 pages, 11 figures, 6 table
Precision Measurement of the Boron to Carbon Flux Ratio in Cosmic Rays from 1.9 GV to 2.6 TV with the Alpha Magnetic Spectrometer on the International Space Station
Knowledge of the rigidity dependence of the boron to carbon flux ratio (B/C) is important in understanding the propagation of cosmic rays. The precise measurement of the B/C ratio from 1.9 GV to 2.6 TV, based on 2.3 million boron and 8.3 million carbon nuclei collected by AMS during the first 5 years of operation, is presented. The detailed variation with rigidity of the B/C spectral index is reported for the first time. The B/C ratio does not show any significant structures in contrast to many cosmic ray models that require such structures at high rigidities. Remarkably, above 65 GV, the B/C ratio is well described by a single power law R[superscript Δ] with index Δ=-0.333±0.014(fit)±0.005(syst), in good agreement with the Kolmogorov theory of turbulence which predicts Δ=-1/3 asymptotically.National Science Foundation (U.S.) (Grants 1455202 and 1551980)Wyle Research (Firm) (Grant 2014/T72497)United States. National Aeronautics and Space Administration (NASA Earth and Space Science Fellowship Grant HELIO15F-0005
Relative Composition and Energy Spectra of Light Nuclei in Cosmic Rays: Results from AMS-01
Measurement of the chemical and isotopic composition of cosmic rays is essential for the precise understanding of their propagation in the galaxy. While the model parameters are mainly determined using the B/C ratio, the study of extended sets of ratios can provide stronger constraints on the propagation models. In this paper, the relative abundances of light-nuclei lithium, beryllium, boron, and carbon are presented. The secondary-to-primary ratios Li/C, Be/C, and B/C have been measured in the kinetic energy range 0.35-45 GeV nucleon[superscript –1]. The isotopic ratio [superscript 7]Li/[superscript 6]Li is also determined in the magnetic rigidity interval 2.5-6.3 GV. The secondary-to-secondary ratios Li/Be, Li/B, and Be/B are also reported. These measurements are based on the data collected by the Alpha Magnetic Spectrometer AMS-01 during the STS-91 space shuttle flight in 1998 June. Our experimental results are in substantial agreement with other measurements, where they exist. We describe our light-nuclei data with a diffusive-reacceleration model. A 10%-15% overproduction of Be is found in the model predictions and can be attributed to uncertainties in the production cross-section data
Solar energetic electron events measured by MESSENGER and Solar Orbiter. Peak intensity and energy spectrum radial dependences: statistical analysis
Context/Aims: We present a list of 61 solar energetic electron (SEE) events
measured by the MESSENGER mission and the radial dependences of the electron
peak intensity and the peak-intensity energy spectrum. The analysis comprises
the period from 2010 to 2015, when MESSENGER heliocentric distance varied
between 0.31 and 0.47 au. We also show the radial dependencies for a shorter
list of 12 SEE events measured in February and March 2022 by spacecraft near 1
au and by Solar Orbiter around its first close perihelion at 0.32 au.
Results: Due to the elevated background intensity level of the particle
instrument on board MESSENGER, the SEE events measured by this mission are
necessarily large and intense; most of them accompanied by a CME-driven shock,
being widespread in heliolongitude, and displaying relativistic (1 MeV)
electron intensity enhancements. The two main conclusions derived from the
analysis of the large SEE events measured by MESSENGER, which are generally
supported by Solar Orbiter's data results, are: (1) There is a wide variability
in the radial dependence of the electron peak intensity between 0.3 au
and 1 au, but the peak intensities of the energetic electrons decrease
with radial distance from the Sun in 27 out of 28 events. On average and within
the uncertainties, we find a radial dependence consistent with . (2)
The electron spectral index found in the energy range around 200 keV
(200) of the backward-scattered population near 0.3 au measured by
MESSENGER is harder in 19 out of 20 (15 out of 18) events by a median factor of
20% (10%) when comparing to the anti-sunward propagating beam
(backward-scattered population) near 1 au.Comment: 20 pages, 13 figure
On the relevance of preprocessing in predictive maintenance for dynamic systems
The complexity involved in the process of real-time data-driven monitoring dynamic systems for predicted maintenance is usually huge. With more or less in-depth any data-driven approach is sensitive to data preprocessing, understood as any data treatment prior to the application of the monitoring model, being sometimes crucial for the final development of the employed monitoring technique. The aim of this work is to quantify the sensitiveness of data-driven predictive maintenance models in dynamic systems in an exhaustive way.
We consider a couple of predictive maintenance scenarios, each of them defined by some public available data. For each scenario, we consider its properties and apply several techniques for each of the successive preprocessing steps, e.g. data cleaning, missing values treatment, outlier detection, feature selection, or imbalance compensation. The pretreatment configurations, i.e. sequential combinations of techniques from different preprocessing steps, are considered together with different monitoring approaches, in order to determine the relevance of data preprocessing for predictive maintenance in dynamical systems
First near-relativistic solar electron events observed by EPD onboard Solar Orbiter
Context. Solar Orbiter, launched in February 2020, started its cruise phase in June 2020, in coincidence with its first perihelion at 0.51 au from the
Sun. The in situ instruments onboard, including the Energetic Particle Detector (EPD), operate continuously during the cruise phase enabling the
observation of solar energetic particles.
Aims. In situ measurements of the first near-relativistic solar electron events observed in July 2020 by EPD are analyzed and the solar origins and
the conditions for the interplanetary transport of these particles investigated.
Methods. Electron observations from keV energies to the near-relativistic range were combined with the detection of type III radio bursts and
extreme ultraviolet (EUV) observations from multiple spacecraft in order to identify the solar origin of the electron events. Electron anisotropies
and timing as well as the plasma and magnetic field environment were evaluated to characterize the interplanetary transport conditions.
Results. All electron events were clearly associated with type III radio bursts. EUV jets were also found in association with all of them except
one. A diversity of time profiles and pitch-angle distributions was observed. Different source locations and different magnetic connectivity and
transport conditions were likely involved. The July 11 event was also detected by Wind, separated 107 degrees in longitude from Solar Orbiter.
For the July 22 event, the Suprathermal Electron and Proton (STEP) sensor of EPD allowed for us to not only resolve multiple electron injections
at low energies, but it also provided an exceptionally high pitch-angle resolution of a very anisotropic beam. This, together with radio observations
of local Langmuir waves suggest a very good magnetic connection during the July 22 event. This scenario is challenged by a high-frequency
occultation of the type III radio burst and a nominally non-direct connection to the source; therefore, magnetic connectivity requires further
investigation
Advances in energetic particle physics with Solar Orbiter
The Sun drives a supersonic wind which inflates a giant plasma bubble in our very local interstellar neighborhood, the heliosphere. Its boundaries and the turbulent magnetic field shield the solar system from much of the interstellar medium as well as the low-energy portion of galactic cosmic rays (GCRs) which are accelerated primarily by super-nova-driven shocks in our galaxy. The heliosphere is bathed in an extremely variable background of energetic ions and electrons which originate from a number of sources. Solar energetic particles (SEPs) are accelerated in the vicinity of the Sun, whereas shocks driven by solar disturbances are observed to accelerate energetic storm particles (ESPs). Moreover, a dilute population with a distinct composition forms the anomalous cosmic rays (ACRs) which are of a mixed interstellar-heliospheric origin. Particles are also accelerated at planetary bow shocks.
In February 2020, the European Space Agency (ESA) launched Solar Orbiter, a science mission to answer the question how the Sun creates and controls the heliosphere. Its orbit brings it within 0.3 astronomical units (au) from the Sun and will also reach moderately high solar latitudes to allow to understand why solar activity changes with time. The spacecraft carries instruments which observe the Sun and its surrounding remotely, others that measure the local environment, and some can track solar disturbances as they travel away from the Sun.
The Energetic Particle Detector (EPD) on Solar Orbiter measures suprathermal and energetic particles in the energy range from a few keV up to (near-) relativistic energies (tens of MeV for
electrons and about >100 MeV/nuc for ions). Together with the other sophisticated instruments on Solar Orbiter it is designed to unravel how solar eruptions produce energetic particle radiation that fills the heliosphere
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