4,146 research outputs found

    Concept of a court or tribunal under the reference for a preliminary ruling : who can refer questions to the Court of Justice of the EU?

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    Who can refer a question on the interpretation and validity of EU law to the Court of Justice of the EU (CJEU)? The most evident answer is a court or tribunal from a Member State, as it is established in the EU Treaties. The CJEU has developed a European concept of a court or tribunal through case law, but the EU Member States have diverse legal systems and there is no uniformity on the consideration of some bodies as a court or tribunal. Furthermore, the CJEU has had some problems with the interpretation of what a court or tribunal is, has added new criteria and has departed from some positions. On top of that, the EU has been growing and each enlargement has brought and will bring countries with more diverse legal systems. Because of that, the case law of the CJEU should be firm in order to avoid legal uncertainty aboutwho is truly empowered to use the procedure. The aim of this study is to analyse the concept of a court or tribunal through the relevant case law where the criteria have been set and where certain particular bodies which do not exercise a pure judicial function have been considered competent to raise questions

    Exploring Content Management Issues in Air Force On-Line Communities of Practice: A Multiple Case Study Approach

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    The practice of content management attempts regardless of platform to ensure that pertinent information is current, relevant, and presented in a usable manner. The Air Force Communities of Practice (CoPs) are hosted by AFMC/DRW, The purpose of these CoPs is to facilitate and promote an environment of capturing and sharing knowledge among members of a particular field task or common practice. As the host for these CoPs AFMC/DRW desires to increase CoP participation efficiency and effectiveness. Addressing existing or potential content management issues will help do so. This multiple-case study research observed and interviewed managers and members of eight active CoPs busted by AFMC/DRW. This research suggested that the interviewed CoPs currently use no formally documented content management processes. Some CoP members indicated developing formal content management processes and procedures establishing a good taxonomy and better defining roles and responsibilities of content owners may help solve future content management Issues

    Short dynamic fibrils in sunspot chromospheres

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    Sunspot chromospheres display vigorous oscillatory signature when observed in chromospheric diagnostics like the strong Ca II lines and H-alpha. New high-resolution sunspot observations from the Swedish 1-m Solar Telescope show the ubiquitous presence of small-scale periodic jet-like features that move up and down. This phenomenon has not been described before. Their typical width is about 0.3 arcsec and they display clear parabolic trajectories in space-time diagrams. The maximum extension of the top of the jets is lowest in the umbra, a few 100 km, and progressively longer further away from the umbra in the penumbra, with the longest more than 1000 km. These jets resemble dynamic fibrils found in plage regions but at smaller extensions. LTE inversion of spectro-polarimetric Ca II 8542 observations enabled for a comparison of the magnetic field inclination and the properties of these short jets. We find that the most extended of these jets also have longer periods and tend to be located in regions with more horizontal magnetic fields. This is a direct observational confirmation of the mechanism of long-period waves propagating along inclined magnetic fields into the solar chromosphere. This mechanism was identified earlier as the driver of dynamic fibrils in plage, part of the mottles in quiet Sun, and type I spicules at the limb. The sunspot dynamic fibrils that we report here represent a new class of manifestation of this mechanism. They are not the same as the transient penumbral and umbral micro-jets reported earlier.Comment: animations of figures can be found at http://folk.uio.no/rouppe/dfsunspot

    Is the sky the limit? Performance of the revamped Swedish 1-m Solar Telescope and its blue- and red-beam re-imaging systems

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    We demonstrate that for data recorded with a solar telescope that uses adaptive optics and/or post-processing to compensate for many low- and high-order aberrations, the RMS granulation contrast is directly proportional to the Strehl ratio calculated from the residual (small-scale) wavefront error. We demonstrate that the wings of the high-order compensated PSF for SST are likely to extend to a radius of not more than about 2 arcsec, consistent with earlier conclusions drawn from straylight compensation of sunspot images. We report on simultaneous measurements of seeing and solar granulation contrast averaged over 2 sec time intervals at several wavelengths from 525 nm to 853.6 nm on the red-beam (CRISP beam) and wavelengths from 395 nm to 484 nm on the blue-beam (CHROMIS beam). These data were recorded with the Swedish 1-m Solar Telescope (SST) that has been revamped with an 85-electrode adaptive mirror and a new tip-tilt mirror, both of which were polished to exceptionally high optical quality. The highest 2-sec average image contrast measured in April 2015 through 0.3-0.9 nm interference filters at 525 nm, 557 nm, 630 nm and 853.5 nm with compensation only for the diffraction limited point spread function of SST is 11.8%, 11.8%, 10.2% and 7.2% respectively. Similarly, the highest 2-sec contrast measured at 395 nm, 400 nm and 484 nm in May 2016 through 0.37-1.3 nm filters is 16%, 16% and 12.5% respectively. The granulation contrast observed with SST compares favorably with that of other telescopes. Simultaneously with the above wideband red-beam data, we also recorded narrow-band continuum images with the CRISP imaging spectropolarimeter. We find that contrasts measured with CRISP are entirely consistent with the corresponding wide-band contrasts, demonstrating that any additional image degradation by the CRISP etalons and telecentric optical system is marginal or even insignificant.Comment: In press in Astronomy & Astrophysic

    Una actividad física eficiente ante el reto de una sociedad de jóvenes influenciada por el modernismo y la tecnología

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    Actualmente los jóvenes se encuentran influenciados por un estilo de vida dominado por la modernidad y los avances tecnológicos, lo que deriva en una vida sedentaria que produce efectos nocivos en todos los sentidos y todos los ámbitos. Esto, aunado a los programas de un sistema institucional educativo y deportivo con innumerables carencias, nos lleva a una situación más complicada, en la que se añaden factores perjudiciales que abarcan la ignorancia, la incapacidad y los intereses personales, que no nos ayudan a edificar alternativas que comiencen a funcionar. Es primordial el establecimiento de una solución pronta y efectiva, encaminada a sistematizar una actividad física adecuada, basada en argumentos científicos y métodos acordes, que nos provean los diversos beneficios que su práctica otorga y nos ayuden a detener el proceso de deterioro físico, al cual el ritmo de vida actual no arroja

    Chromospheric condensations and magnetic field in a C3.6-class flare studied via He I D3 spectro-polarimetry

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    Context. Magnetic reconnection during flares takes place in the corona but a substantial part of flare energy is deposited in the chromosphere. However, high-resolution spectro-polarimetric chromospheric observations of flares are very rare. The most used observables are Ca II 8542 {\AA} and He I 10830 {\AA}. Aims. We aim to study the chromosphere during a C3.6 class flare via spectro-polarimetric observations of the He I D3 line. Methods. We present the first SST/CRISP spectro-polarimetric observations of He I D3. We analyze the data using the inversion code HAZEL, and estimate the LOS velocity and the magnetic field vector. Results. Strong He I D3 emission at the flare footpoints, as well as strong He I D3 absorption profiles tracing the flaring loops are observed during the flare. The He I D3 traveling emission kernels at the flare footpoints exhibit strong chromospheric condensations of up to \sim 60 km/s at their leading edge. Our observations suggest that such condensations result in shocking the deep chromosphere, causing broad and modestly blueshifted He I D3 profiles indicating subsequent upflows. A strong and rather vertical magnetic field of up to \sim 2500 G is measured in the flare footpoints, confirming that the He I D3 line is likely formed in the deep chromosphere at those locations. We provide chromospheric line-of-sight velocity and magnetic field maps obtained via He I D3 inversions. We propose a fan-spine configuration as the flare magnetic field topology. Conclusions. The He I D3 line is an excellent diagnostic to study the chromosphere during flares. The impact of strong condensations on the deep chromosphere has been observed. Detailed maps of the flare dynamics and the magnetic field are obtained.Comment: Accepted for publication in A&

    Fan-shaped jets above the light bridge of a sunspot driven by reconnection

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    We report on a fan-shaped set of high-speed jets above a strongly magnetized light bridge (LB) of a sunspot observed in the Hα\alpha line. We study the origin, dynamics and thermal properties of the jets using high-resolution imaging spectroscopy in Hα\alpha from the Swedish 1-m Solar Telescope and data from the Solar Dynamics Observatory and Hinode. The Hα\alpha jets have lengths of 7-38 Mm, are impulsively accelerated to a speed of 100\sim 100 km/s close to photospheric footpoints in the LB, and exhibit a constant deceleration consistent with solar effective gravity. They are predominantly launched from one edge of the light bridge, and their footpoints appear bright in the Hα\alpha wings. AIA data indicates elongated brightenings that are nearly co-spatial with the Hα\alpha jets. We interpret them as jets of at least transition region temperatures. The magnetic field in the light bridge has a strength of 0.820.8-2 kG and it is nearly horizontal. All jet properties are consistent with magnetic reconnection as the driver.Comment: Accepted for publication in A&

    A Hot Downflowing Model Atmosphere For Umbral Flashes And The Physical Properties Of Their Dark Fibrils

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    We perform NLTE inversions in a large set of umbral flashes, including the dark fibrils visible within them, and in the quiescent umbra by using the inversion code NICOLE on a set of full Stokes high-resolution Ca II 8542 A observations of a sunspot at disk center. We find that the dark structures have Stokes profiles that are distinct from those of the quiescent and flashed regions. They are best reproduced by atmospheres that are more similar to the flashed atmosphere in terms of velocities, even if with reduced amplitudes. We also find two sets of solutions that finely fit the flashed profiles: a set that is upflowing, featuring a transition region that is deeper than in the quiescent case and preceded by a slight dip in temperature, and a second solution with a hotter atmosphere in the chromosphere but featuring downflows close to the speed of sound at such heights. Such downflows may be related, or even dependent, on the presence of coronal loops, rooted in the umbra of sunspots, as is the case in the region analyzed. Similar loops have been recently observed to have supersonic downflows in the transition region and are consistent with the earlier "sunspot plumes" which were invariably found to display strong downflows in sunspots. Finally we find, on average, a magnetic field reduction in the flashed areas, suggesting that the shock pressure is moving field lines in the upper layers.Comment: Accepted in June for publication at ApJ. Comments to [email protected] or [email protected]
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