Evolution of small-scale magnetic elements in the vicinity of granular-size swirl convective motions

Advances in solar instrumentation have led to a widespread usage of time series to study the dynamics of solar features, specially at small spatial scales and at very fast cadences. Physical processes at such scales are determinant as building blocks for many others occurring from the lower to the upper layers of the solar atmosphere and beyond, ultimately for understanding the bigger picture of solar activity. Ground-based (SST) and space-borne (Hinode) high-resolution solar data are analyzed in a quiet Sun region displaying negative polarity small-scale magnetic concentrations and a cluster of bright points observed in G-band and Ca II H images. The studied region is characterized by the presence of two small-scale convective vortex-type plasma motions, one of which appears to be affecting the dynamics of both, magnetic features and bright points in its vicinity and therefore the main target of our investigations. We followed the evolution of bright points, intensity variations at different atmospheric heights and magnetic evolution for a set of interesting selected regions. A description of the evolution of the photospheric plasma motions in the region nearby the convective vortex is shown, as well as some plausible cases for convective collapse detected in Stokes profiles.Comment: 9 figure

Comment on current correlators in QCD at finite temperature

We address some criticisms by Eletsky and Ioffe on the extension of QCD sum rules to finite temperature. We argue that this extension is possible, provided the Operator Product Expansion and QCD-hadron duality remain valid at non-zero temperature. We discuss evidence in support of this from QCD, and from the exactly solvable two- dimensional sigma model O(N) in the large N limit, and the Schwinger model.Comment: 10 pages, LATEX file, UCT-TP-208/94, April 199

Theory of extraordinary transmission of light through quasiperiodic arrays of subwavelength holes

By using a theoretical formalism able to work in both real and k-spaces, the physical origin of the phenomenon of extraordinary transmission of light through quasi-periodic arrays of holes is revealed. Long-range order present in a quasiperiodic array selects the wavevector(s) of the surface electromagnetic mode(s) that allows an efficient transmission of light through subwavelength holes.Comment: 4 pages, 4 figure

Fossil group origins: VIII RXJ075243.6+455653 a transitionary fossil group

It is thought that fossil systems are relics of structure formation in the primitive Universe. They are galaxy aggregations that have assembled their mass at high redshift with few or no subsequent accretion. Observationally these systems are selected by large magnitude gaps between their 1st and 2nd ranked galaxies. Nevertheless, there is still debate over whether or not this observational criterium selects dynamically evolved ancient systems. We have studied the properties of the nearby fossil group RXJ075243.6+455653 in order to understand the mass assembly of this system. Deep spectroscopic observations allow us to construct the galaxy luminosity function (LF) of RXJ075243.6+455653 down to M*+ 6. The analysis of the faint-end of the LF in groups and clusters provides valuable information about the mass assembly of the system. In addition, we have analyzed the nearby large-scale structure around this group. We identified 26 group members within r200=0.9 Mpc. The LF of the group shows a flat faint-end slope ( -1.08 +/- 0.33). This low density of dwarf galaxies is confirmed by the low value of the dwarf-to-giant ratio (DGR = 0.99 +/- 0.49) for this system. Both the lack of dwarf galaxies and the low luminosity of the BGG suggests that RXJ075243.6+455653 still has to accrete mass from its nearby environment. This mass accretion will be achieved because it is the dominant structure of a rich environment formed by several groups of galaxies (15) within 7 Mpc from the group center and with +/- 1000$ km/s. RXJ075243.6+455653 is a group of galaxies that has not yet completed the process of its mass assembly. This new mass accretion will change the fossil state of the group. This group is an example of a galaxy aggregation selected by a large magnitude gap but still in the process of the accretion of its mass (Abridged).Comment: 9 pages, 9 figures, accepted in A&

Magyarcarcinidae new family (Crustacea: Decapoda: Goneplacoidea), and description of Magyarcarcinus yebraensisnew species, from the Bartonian (Middle Eocene) of the Jaca basin, south-central Pyrenees (Aragón, N Spain)

Magyarcarcinidae, nova família (Crustacea: Decapoda: Goneplacoidea), i descripció de Magyarcarcinus yebraensis nova espècie del Bartonià (Eocè mitjà) de la conca de Jaca, Pirineus centrals (Aragó, N d’Espanya)Es proposa la nova família Magyarcarcinidae per tal d’acomodar-hi el gènere Magyarcarcinus. S’erigeix una nova espècie, Magyarcarcinus yebraensis, en base a exemplars procedents de nivells del Bartonià de la Formació Margasde Arguís a Yebra de Basa (Aragó, N d’Espanya). Al mateix temps es fa una detallada comparació amb totes les famílies de Goneplacoidea i altres tàxons relacionats. També es confirma la relació entre la fauna de decàpodes de l’Eocè mitjà de les illes britàniques i la del marge occidental del Tetis, així com les possibles vies migratòries.Magyarcarcinidae is proposed as a new family to accommodate the genus Magyarcarcinus. A new species, Magyarcarcinus yebraensisis erected after specimens from Bartonian levels of the Margas de Arguís Formation at Yebra de Basa (Aragón, N Spain). A detailed comparison with all the Goneplacoidea families and related taxa is presented. Relationship between both Tethyan and British Middle Eocene decapod faunas are herein confirmed, as well as their migration paths.Magyarcarcinidae, nueva familia (Crustacea: Decapoda: Goneplacoidea), y descripción de Magyarcarcinus yebraensisn. sp. del Bartoniense (Eoceno medio) de la cuenca de Jaca, Pirineo central (Aragón, N de España)Se propone la nueva familia Magyarcarcinidae, para acomodar el género Magyarcarcinus. En base a especímenes de niveles del Bartoniense de la Formación Margas de Arguís en Yebra de Basa (Aragón, N de España),se erige una nueva especie, Magyarcarcinus yebraensis. Asimismo, se realiza una detallada comparación con todas las familias de Goneplacoidea así como con otros taxones relacionados. También se confirma la relación entre la fauna de decápodos del Eoceno medio de las islas británicas y la del margen occidental del Tetis, así como las posibles vías migratorias

Electromagnetic proton form factors in large NcN_{c} QCD

The electromagnetic form factors of the proton are obtained using a particular realization of QCD in the large $N_c$ limit (${QCD}_{\infty}$), which sums up the infinite number of zero-width resonances to yield an Euler's Beta function (Dual-${QCD}_{\infty}$). The form factors $F_1(q^2)$ and $F_2(q^2)$, as well as $G_M(q^2)$ agree very well with reanalyzed space-like data in the whole range of momentum transfer. In addition, the predicted ratio $\mu_p G_E/G_M$ is in good agreement with recent polarization transfer measurements at Jefferson Lab.Comment: 10 page