830 research outputs found

    La «Centesimus Annus»: una guía para el futuro

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    La doctrina social de la Iglesia: perspectivas de futuro

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    Rapid Decreasing in the Orbital Period of the Detached White Dwarf?main Sequence Binary SDSS J143547.87+373338.5

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    SDSS J143547.87+373338.5 is a detached eclipsing binary that contains a white dwarf with a mass of 0.5 M⊙ and a fully convective star with a mass of 0.21 M⊙. The eclipsing binary was monitored photometrically from 2009 March 24 to 2015 April 10, by using two 2.4-m telescopes in China and in Thailand. The changes in the orbital period are analyzed based on eight newly determined eclipse times together with those compiled from the literature. It is found that the observed?calculated (O?C) diagram shows a downward parabolic change that reveals a continuous period decrease at a rate of dot{P}=-8.04× {10}-11 s s‑1. According to the standard theory of cataclysmic variables, angular momentum loss (AML) via magnetic braking (MB) is stopped for fully convective stars. However, this period decrease is too large to be caused by AML via gravitational radiation (GR), indicating that there could be some extra source of AML beyond GR, but the predicted mass-loss rates from MB seem unrealistically large. The other possibility is that the O?C diagram may show a cyclic oscillation with a period of 7.72 years and a small amplitude of 0.ͩ000525. The cyclic change can be explained as the light-travel-time effect via the presence of a third body because the required energy for the magnetic activity cycle is much larger than that radiated from the secondary in a whole cycle. The mass of the potential third body is determined to be {M}3{sin}{i}prime =0.0189(+/- 0.0016) M⊙ when a total mass of 0.71 M⊙ for SDSS J143547.87+373338.5 is adopted. For orbital inclinations {i}prime ≥slant 15uildrel{circ}over{.} 9, it would be below the stable hydrogen-burning limit of M3 ∼ 0.072 M⊙, and thus the third body would be a brown dwarf.Fil: Qian, S. B.. Chinese Academy of Sciences; República de ChinaFil: Han, Z. T.. Chinese Academy of Sciences; República de ChinaFil: Soonthornthum, B.. National Astronomical Research Institute of Thailand; TailandiaFil: Zhu, L. Y.. Chinese Academy of Sciences; República de ChinaFil: He, J. J.. Chinese Academy of Sciences; República de ChinaFil: Rattanasoon, S.. National Astronomical Research Institute of Thailand; TailandiaFil: Aukkaravittayapun, S.. National Astronomical Research Institute of Thailand; TailandiaFil: Liao, W. P.. Chinese Academy of Sciences; República de ChinaFil: Zhao, E. G.. Chinese Academy of Sciences; República de ChinaFil: Zhang, J.. Chinese Academy of Sciences; República de ChinaFil: Fernandez Lajus, Eduardo Eusebio. Universidad Nacional de la Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica la Plata; Argentin

    Fractura avulsión aislada del ligamento cruzado posterior de la rodilla

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    La fractura avulsión aislada del ligamento cruzado posterior es una lesión infrecuente, que en ocasiones puede estar enmascarada por otras lesiones asociadas, y que desencadena un cuadro de inestabilidad de rodilla si no se trata adecuadamente. El tratamiento quirúrgico es el de elección en la mayoría de los casos. Presentamos 14 casos tratados en nuestro servicio, 3 de ellos conservadoramente y el resto mediante reducción abierta y fijación con tornillo, con buenos resultados funcionales.Isolated avulsion fracture of the posterior cruciate ligament is a rare injury which can be masked by associated injuries, leaving an unstable knee if not properly treated. Surgery is the elective treatment in many cases. Fourteen cases were managed, three of them nonoperative, and the others with open reduction and internal fixation with screw. Good functional results were obtained

    Highly fluorinated erbium(III) complexes for emission in the C-band

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    Two highly fluorinated Er3+ complexes with three 6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionate (fod) groups and either bipyridine (bipy) or bathophenantholine (bath) as the ancillary ligand emitting at the C-band (third communication window for fiber transmission) are presented. These complexes are the result of a design process aimed at decreasing the vibrational quenching from high frequency oscillators. The structure of [Er(fod)3(bipy)] has been elucidated by single-crystal X-ray diffraction, while Sparkle/PM6 and Sparkle/PM7 semi-empirical calculations have been used to model the ground state geometry for [Er(fod)3(bath)]. Photoluminescence studies confirm sensitization of the Er3+ ions by antenna effect, leading to NIR emission at 1.53 μm. This energy transfer proves to be more efficient for [Er(fod)3(bath)] as a result of the bulkier and more rigid structure of bath diimide. The good thermal stability of the materials up to over 200 °C allows envisaging their use in erbium-doped waveguides, NIR-OLEDs or other optoelectronic devices

    ESA’s Soil Moisture and Ocean Salinity Mission - An overview on the mission’s performance and scientific results

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    European Geosciences Union General Assembly 2014 (EGU2014), 27 april - 2 may 2014, Vienna, Austria.-- 1 pageThe Soil Moisture and Ocean Salinity (SMOS) mission, launched on 2 November 2009, is the European Space Agency’s (ESA) second Earth Explorer Opportunity mission. The scientific objectives of the SMOS mission directly respond to the need for global observations of soil moisture and ocean salinity, two key variables used in predictive hydrological, oceanographic and atmospheric models. SMOS observations also provide information on the characterisation of ice and snow covered surfaces and the sea ice effect on ocean-atmosphere heat fluxes and dynamics, which affects large-scale processes of the Earth’s climate system. This paper will provide an overview on the various aspects of the SMOS mission, such as 1. The performance of the mission after more than 5 years in orbit: The SMOS mission has been in routine operations since May 2010, following the successful completion of the 6-months commissioning phase. The paper will summarise the technical and scientific status of the mission, including the status of the RFI detection and mitigation and its effect on the data products. SMOS has so far provided very reliable instrument operations, data processing and dissemination to users. The paper will also provide an overview on the MIRAS instrument performance, including the instrument calibration and level 1 brightness temperature data processing. 2. An overview on the SMOS data products: SMOS provides continuously level 1 (brightness temperature) and level 2 (soil moisture and ocean salinity) to its scientific user community since summer 2010. SMOS also provides brightness temperature data (level 1 data) to ECMWF in near-real time (NRT), who assimilates the data into their forecasting system. New services have been established to deliver a tailored NRT data product via the WMO’s GTS and EUMETSAT’s EUMETCast data dissemination systems to other operational agencies. This will open up new operational applications for SMOS data. Other data products are under development, responding to the requirements of the science community in particular in the area of hydrology, climate, land use and ship routing, namely a frozen soil indicator, data products for freeze/thaw periods, sea ice thickness and vegetation water content. 3. Provide an update on the overall validation approach and recent activities: SMOS data products are continuously improved and approach the scientific mission objectives. Validation activities are essential to ensure high data quality. ESA in collaboration with national agencies and institutions maintains a frame for validation activities such as reference sites, ground based observations as well as campaigns. The paper will provide an update on recent activities, such as the activities at DOME-C. 4. Summarise the collaboration with other space-borne L-band sensors, such as NASA’s Aquarius and SMAP missionsPeer Reviewe
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