1,589 research outputs found
El yacimiento de vertebrados de cortes de Baza I (Depresión de Guadix-Baza). Nota preliminar
En el presente trabajo se estudia un yacimiento de micromamíferos en la Depresión de Guadix-Baza. La fauna estudiada permite datar la zona de Saint Vallier. Se señalan asimismo niveles marinos cuaternarios a 680 m de altura
El yacimiento de vertebrados de cortes de Baza I (Depresión de Guadix-Baza). Nota preliminar
En el presente trabajo se estudia un yacimiento de micromamíferos en la Depresión de Guadix-Baza. La fauna estudiada permite datar la zona de Saint Vallier. Se señalan asimismo niveles marinos cuaternarios a 680 m de altura
Orbital characterization of superbolides observed from space: dynamical association with near-Earth objects, meteoroid streams and identification of hyperbolic meteoroids
There is an unceasing incoming flux of extraterrestrial materials reaching
the Earth's atmosphere. Some of these objects produce luminous columns when
they ablate during the hypersonic encounter with air molecules. A few fireballs
occur each year bright enough to be detected from space. The source of these
events is still a matter of debate, but it is generally accepted that they are
of sporadic origin. We studied the NASA-JPL Center for NEOs Studies (CNEOS)
fireball database to infer the dynamic origin of large bolides produced by
meter-sized projectiles that impacted our planet. These likely
meteorite-dropping events were recorded by the US Government satellite sensors.
We estimated the false-positive rate and analyzed the time evolution of
multiple orbit dissimilarity criteria concerning potential associations with
near-Earth objects and meteoroid streams. We found that at least 16% of the
large bolides could be associated with meteoroid streams, about 4% are likely
associated with near-Earth asteroids, and 4% may be linked to near-Earth
comets. This implies that a significant fraction of meter-sized impactors
producing large bolides may have an asteroidal or cometary origin. In addition,
we found at least three bolides having hyperbolic orbits with high tensile
strength values. Meter-sized meteoroids of interstellar origin could be more
common than previously thought, representing about 1% of the flux of large
bolides. The inferred bulk physical properties suggest that the interstellar
medium could bias these projectiles towards high strength rocks with the
ability to survive prolonged exposure to the harsh interstellar space
conditions.Comment: Accepted for publication in The Astronomical Journal (AAS38905R1
A photometric monitoring of bright high-amplitude delta Scuti stars. II. Period updates for seven stars
We present new photometric data for seven high-amplitude delta Scuti stars.
The observations were acquired between 1996 and 2002, mostly in the Johnson
photometric system. For one star (GW UMa), our observations are the first since
the discovery of its pulsational nature from the Hipparcos data.The primary
goal of this project was to update our knowledge on the period variations of
the target stars. For this, we have collected all available photometric
observations from the literature and constructed decades-long O-C diagrams of
the stars. This traditional method is useful because of the single-periodic
nature of the light variations. Text-book examples of slow period evolution (XX
Cyg, DY Her, DY Peg) and cyclic period changes due to light-time effect (LITE)
in a binary system (SZ Lyn) are updated with the new observations. For YZ Boo,
we find a period decrease instead of increase. The previously suggested
LITE-solution of BE Lyn (Kiss & Szatmary 1995) is not supported with the new
O-C diagram. Instead of that, we suspect the presence of transient light curve
shape variations mimicking small period changes.Comment: 11 pages, 15 figures, accepted for publication in A&
Dynamical Study of a Moored Vessel Using Computer Vision
[Abstract]: Wind and wave effects have a major impact on the design of mooring and anchoring systems, whose purpose is to prevent the movement of the cargo and the moored ship while optimizing the operations which have to take place in port. The dynamic behavior of a ship moored in waves has been mathematically described and interactions between ships and environmental loads have been commonly tested for different docks and mooring systems in scale models. However, the behavior of real ships in true mooring conditions has not been properly addressed in scientific literature. This paper proposes a novel computer vision technique to monitor moored ships. This approach uses the correlation of visual features in the images of the ship to estimate its movements along time. The proposed technique has been validated in laboratory conditions and applied in a real scenario to study the behavior of the ship Urania Mella in the Outer Port of A Coruña (Spain), in Punta Langosteira, obtaining very promising results.The authors wish to thank the Port Authority of A Coruña, Aquática Ingeniería Civil and Siport21 for their cooperation and technical assistance, and the Urania Mella owners and crew for the facilities on board. The development of the artificial vision algorithm was partially funded by FEDER funds and Spanish Ministry of Economy, Industry and Competitiveness, R & D National Plan, within the projects CGL2012-34688 and BIA2017- 86738-R
Taxonomy and hierarchy of psychological abuse strategies in intimate partner relationships
This study focuses on the analysis from of a psychosocial perspective of the components of psychological abuse in intimate partner relationships. Following a review of studies on the subject, the main objective that emerged was the need for a new taxonomy of strategies of psychological abuse accompanied by the corresponding operational definitions. After the proposal of this new classification, a second objective emerged that consisted of submitting it for evaluation by a group of experts through a Delphi study, in which thirty-two experts from the academic and professional worlds participated. These experts were asked to assess the suitability of the system categories, and to grade quantitatively the severity of the impact made by each of the strategies on the global phenomenon of psychological abuse in couples. The results show that the experts ratified the new classification of strategies and their operational definitions, thus endorsing their content and construct validity. In addition, they classified the strategies based on their degree of severity; those of an emotional nature were considered the severest, followed by those related to the immediate context, with those of a cognitive type in third place, and lastly, the behavioural ones. Finally, we discuss the results, and their implications.
Este estudio se centra en analizar los componentes del abuso psicológico en la violencia de pareja adulta y contra la mujer desde un enfoque psicosocial. Tras realizar una revisión de los estudios sobre el tema, se plantea como primer objetivo el proponer una nueva taxonomía de estrategias de abuso psicológico, acompañadas de sus respectivas definiciones operativas. A partir de esta nueva clasificación, se traza un segundo objetivo que se centra en someter esta clasificación al juicio de un grupo de expertos a través de un estudio Delphi, en el que han participado 32 expertos de los ámbitos académico - universitario y profesional. Estos expertos debían juzgar la adecuación del sistema de categorías, además de evaluar cuantitativamente la severidad que aporta cada una de las estrategias al fenómeno global del abuso psicológico en la pareja. Los resultados muestran que los expertos ratifican la nueva clasificación de estrategias y sus definiciones operativas, avalando así su validez de contenido y constructo. Además, jerarquizaron las estrategias de abuso, atribuyendo mayor severidad a las de tipo emocional, seguidas de las relacionadas con el contexto cercano, de las de tipo cognitivo y las de carácter conductual. Se discuten los resultados, sus limitaciones y las implicaciones que pueden derivarse de ellos
Cation-driven electrical conductivity in Ta-doped orthorhombic zirconia ceramics
This paper is devoted to the study of the electrical conductivity of tantalum-doped zirconia ceramics prepared by spark plasma sintering. In this study, the temperature dependence of conductivity in as-prepared specimens and in those previously annealed in air is determined and compared. A semi-empirical model, which is based on the oxidation states of the cations, has been developed and successfully assessed. According to this, the conductivity is basically controlled by the diffusion of tetravalent zirconium cations in both cases, although the concentration of these species varies drastically with the amount of induced oxygen vacancies. This is a quite unexpected fact, since conductivity is normally controlled by anionic diffusion in zirconia ceramics. This option is forbidden here due to the presence of substitutional pentavalent cations. Therefore, conductivity values are much lower than those reported in trivalent or divalent substitutional cation doped zirconia ceramics
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