Resolving the internal magnetic structure of the solar network

We analyze the spectral asymmetry of Stokes V (circularly polarized) profiles of an individual network patch in the quiet Sun observed by Sunrise/IMaX. At a spatial resolution of 0.15"-0.18", the network elements contain substructure which is revealed by the spatial distribution of Stokes V asymmetries. The area asymmetry between the red and blue lobes of Stokes V increases from nearly zero at the core of the structure to values close to unity at its edges (one-lobed profiles). Such a distribution of the area asymmetry is consistent with magnetic fields expanding with height, i.e., an expanding magnetic canopy (which is required to fulfill pressure balance and flux conservation in the solar atmosphere). Inversion of the Stokes I and V profiles of the patch confirms this picture, revealing a decreasing field strength and increasing height of the canopy base from the core to the periphery of the network patch. However, the non-roundish shape of the structure and the presence of negative area and amplitude asymmetries reveal that the scenario is more complex than a canonical flux tube expanding with height surrounded by downflows.Comment: accepted for publication in ApJ Letter

Maltose-binding protein is a potential carrier for oral immunizations

In humans and most animal species such as pigs, vaccination via the oral route is a prerequisite for induction of a protective immunity against enteropathogens. Hereto, live attenuated microorganisms can be used. However, these microorganisms often are either too attenuated to induce sufficient intestinal immunity or are still too virulent resulting in clinical signs. We previously demonstrated that it is possible to induce immunity against enteropathogens by targeting antigen towards enterocytes. Maltose-binding protein (MBP) is part of the maltose/maltodextrin system of Escherichia coli. MBP is a relatively small protein (42.5 kDa) approximately 3 × 4 × 6.5 nm in size with surface residues capable of both hydrogen bonding interactions and hydrophobic interactions. Recombinant proteins are often fused to MPB to improve their yield and to increase their solubility. In mice, these fusion proteins showed an enhanced immunogenicity following systemic immunization. More recently, this has been attributed to interaction of MBP with TLR4 on dendritic cells (DCs). TLR4 is also expressed in the enterocytes of the gut. Therefore, we examined if oral administration of MPB-FedF to 4-week-old pigs could be used to induce an immune response against F18+ verotoxigenic E. coli in pigs. Also we examined if the oral administration of MBP to pigs is able to induce an immune response. In both experiments cholera toxin was used as oral adjuvant

Orphan penumbrae: Submerging horizontal fields

We investigate the properties of orphan penumbrae, which are photospheric filamentary structures observed in active regions near polarity inversion lines that resemble the penumbra of regular sunspots but are not connected to any umbra. We use Hinode data from the Solar Optical Telescope to determine the properties of orphan penumbrae. Spectropolarimetric data are employed to obtain the vector magnetic field and line-of-sight velocities in the photosphere. Magnetograms are used to study the overall evolution of these structures, and G-band and Ca II H filtergrams are to investigate their brightness and apparent horizontal motions. Orphan penumbrae form between regions of opposite polarity in places with horizontal magnetic fields. Their magnetic configuration is that of $\Omega$-shaped flux ropes. In the two cases studied here, the opposite-polarity regions approach each other with time and the whole structure submerges as the penumbral filaments disappear. Orphan penumbrae are very similar to regular penumbrae, including the existence of strong gas flows. Therefore, they could have a similar origin. The main difference between them is the absence of a "background" magnetic field in orphan penumbrae. This could explain most of the observed differences. The fast flows we detect in orphan penumbrae may be caused by the siphon flow mechanism. Based on the similarities between orphan and regular penumbrae, we propose that the Evershed flow is also a manifestation of siphon flows.Comment: 15 pages, 15 figure

Abastament d'aigua en comunitats rurals de El Salvador: Propostes per a la sostenibilitat social.

El capítulo de ejecución puede significar el 80% de la asignación presupuestaria en los proyectos de infraestructura en general, y los de abastecimiento y saneamiento de agua en particular. Sin embargo, factores como seguimiento, evaluación, capacitación, legalización, o sensibilización, a menudo de difícil -si no imposible- justificación económica ante financiadores y donantes, pueden llegar a constituir entre el 80% y el 90% de las causas de fracaso de los proyectos. Este artículo expone la metodología que Ingeniería Sin Fronteras Cataluña (ESF) y la Asociación de Desarrollo Comunal –El Salvador (CORDES) han desarrollado desde el año 1999 en áreas rurales de El Salvador en los aspectos no puramente técnicos de los proyectos que garanticen su sostenibilidad social. Pretende que resulte de utilidad para otros profesionales u organizaciones que trabajen también en el campo del agua en comunidades rurales.El capítol d'execució pot significar el 80% de l'assignació pressupostària en els projectes d'infrastructura en general, i en els d'abastament i sanejament d'aigua en particular. No obstant, factors com ara el seguiment, avaluació, capacitació, legalització, o sensibilització, sovint de difícil -si no impossible- justificació econòmica davant de finançadors i donants, poden arribar a constituir entre el 80% i el 90% de les causes de fracàs dels projectes. Aquest article exposa la metodologia que Enginyeria Sense Fronteres Catalunya (ESF) i l'Associació de Desenvolupament Comunal –El Salvador (CORDES) han desenvolupat des de l'any 1999 en àrees rurals del Salvador en els aspectes no purament tècnics dels projectes que garanteixin la seva sostenibilitat social. Pretén resultar d'utilitat per a altres professionals o organitzacions que treballen també al sector de l'aigua en comunitats rurals.Peer Reviewe

Granular-Scale Elementary Flux Emergence Episodes in a Solar Active Region

We analyze data from Hinode spacecraft taken over two 54-minute periods during the emergence of AR 11024. We focus on small-scale portions within the observed solar active region and discover the appearance of very distinctive small-scale and short-lived dark features in Ca II H chromospheric filtergrams and Stokes I images. The features appear in regions with close-to-zero longitudinal magnetic field, and are observed to increase in length before they eventually disappear. Energy release in the low chromospheric line is detected while the dark features are fading. In time series of magnetograms a diverging bipolar configuration is observed accompanying the appearance of the dark features and the brightenings. The observed phenomena are explained as evidencing elementary flux emergence in the solar atmosphere, i.e small-scale arch filament systems rising up from the photosphere to the lower chromosphere with a length scale of a few solar granules. Brightenings are explained as being the signatures of chromospheric heating triggered by reconnection of the rising loops (once they reached chromospheric heights) with pre-existing magnetic fields as well as to reconnection/cancellation events in U-loop segments of emerging serpentine fields. We study the temporal evolution and dynamics of the events and compare them with the emergence of magnetic loops detected in quiet sun regions and serpentine flux emergence signatures in active regions. Incorporating the novel features of granular-scale flux emergence presented in this study we advance the scenario for serpentine flux emergence.Comment: 24 pages, 9 figures. Accepted for publication in Solar Physic

Imaging Spectropolarimetry with IBIS: Evolution of Bright Points in the Quiet Sun

We present the results from first spectropolarimetric observations of the solar photosphere acquired at the Dunn Solar Telescope with the Interferometric Bidimensional Spectrometer. Full Stokes profiles were measured in the Fe I 630.15 nm and Fe I 630.25 nm lines with high spatial and spectral resolutions for 53 minutes, with a Stokes V noise of 0.003 the continuum intensity level. The dataset allows us to study the evolution of several magnetic features associated with G-band bright points in the quiet Sun. Here we focus on the analysis of three distinct processes, namely the coalescence, fragmentation and cancellation of G-band bright points. Our analysis is based on a SIR inversion of the Stokes I and V profiles of both Fe I lines. The high spatial resolution of the G-band images combined with the inversion results helps to interpret the undergoing physical processes. The appearance (dissolution) of high-contrast G-band bright points is found to be related to the local increase (decrease) of the magnetic filling factor, without appreciable changes in the field strength. The cancellation of opposite-polarity bright points can be the signature of either magnetic reconnection or the emergence/submergence of magnetic loops.Comment: 4 pages, 5 figures, accepted for publication in ApJ Letter