Do quasi-regular structures really exist in the solar photosphere? I. Observational evidence

Two series of solar-granulation images -- the La Palma series of 5 June 1993 and the SOHO MDI series of 17--18 January 1997 -- are analysed both qualitatively and quantitatively. New evidence is presented for the existence of long-lived, quasi-regular structures (first reported by Getling and Brandt (2002)), which no longer appear unusual in images averaged over 1--2-h time intervals. Such structures appear as families of light and dark concentric rings or families of light and dark parallel strips (``ridges'' and ``trenches'' in the brightness distributions). In some cases, rings are combined with radial ``spokes'' and can thus form ``web'' patterns. The characteristic width of a ridge or trench is somewhat larger than the typical size of granules. Running-average movies constructed from the series of images are used to seek such structures. An algorithm is developed to obtain, for automatically selected centres, the radial distributions of the azimuthally averaged intensity, which highlight the concentric-ring patterns. We also present a time-averaged granulation image processed with a software package intended for the detection of geological structures in aerospace images. A technique of running-average-based correlations between the brightness variations at various points of the granular field is developed and indications are found for a dynamical link between the emergence and sinking of hot and cool parcels of the solar plasma. In particular, such a correlation analysis confirms our suggestion that granules -- overheated blobs -- may repeatedly emerge on the solar surface. Based on our study, the critical remarks by Rast (2002) on the original paper by Getling and Brandt (2002) can be dismissed.Comment: 21 page, 8 figures; accepted by "Solar Physics

Comparisons of Supergranule Characteristics During the Solar Minima of Cycles 22/23 and 23/24

Supergranulation is a component of solar convection that manifests itself on the photosphere as a cellular network of around 35 Mm across, with a turnover lifetime of 1-2 days. It is strongly linked to the structure of the magnetic field. The horizontal, divergent flows within supergranule cells carry local field lines to the cell boundaries, while the rotational properties of supergranule upflows may contribute to the restoration of the poloidal field as part of the dynamo mechanism that controls the solar cycle. The solar minimum at the transition from cycle 23 to 24 was notable for its low level of activity and its extended length. It is of interest to study whether the convective phenomena that influences the solar magnetic field during this time differed in character to periods of previous minima. This study investigates three characteristics (velocity components, sizes and lifetimes) of solar supergranulation. Comparisons of these characteristics are made between the minima of cycles 22/23 and 23/24 using MDI Doppler data from 1996 and 2008, respectively. It is found that whereas the lifetimes are equal during both epochs (around 18 h), the sizes are larger in 1996 (35.9 +/- 0.3 Mm) than in 2008 (35.0 +/- 0.3 Mm), while the dominant horizontal velocity flows are weaker (139 +/- 1 m/s in 1996; 141 +/- 1 m/s in 2008). Although numerical differences are seen, they are not conclusive proof of the most recent minimum being inherently unusual.Comment: 22 pages, 5 figures. Solar Physics, in pres

Modeling the Subsurface Structure of Sunspots

While sunspots are easily observed at the solar surface, determining their subsurface structure is not trivial. There are two main hypotheses for the subsurface structure of sunspots: the monolithic model and the cluster model. Local helioseismology is the only means by which we can investigate subphotospheric structure. However, as current linear inversion techniques do not yet allow helioseismology to probe the internal structure with sufficient confidence to distinguish between the monolith and cluster models, the development of physically realistic sunspot models are a priority for helioseismologists. This is because they are not only important indicators of the variety of physical effects that may influence helioseismic inferences in active regions, but they also enable detailed assessments of the validity of helioseismic interpretations through numerical forward modeling. In this paper, we provide a critical review of the existing sunspot models and an overview of numerical methods employed to model wave propagation through model sunspots. We then carry out an helioseismic analysis of the sunspot in Active Region 9787 and address the serious inconsistencies uncovered by \citeauthor{gizonetal2009}~(\citeyear{gizonetal2009,gizonetal2009a}). We find that this sunspot is most probably associated with a shallow, positive wave-speed perturbation (unlike the traditional two-layer model) and that travel-time measurements are consistent with a horizontal outflow in the surrounding moat.Comment: 73 pages, 19 figures, accepted by Solar Physic

Whole genome analysis of a schistosomiasis-transmitting freshwater snail

Biomphalaria snails are instrumental in transmission of the human blood fluke Schistosoma mansoni. With the World Health Organization's goal to eliminate schistosomiasis as a global health problem by 2025, there is now renewed emphasis on snail control. Here, we characterize the genome of Biomphalaria glabrata, a lophotrochozoan protostome, and provide timely and important information on snail biology. We describe aspects of phero-perception, stress responses, immune function and regulation of gene expression that support the persistence of B. glabrata in the field and may define this species as a suitable snail host for S. mansoni. We identify several potential targets for developing novel control measures aimed at reducing snail-mediated transmission of schistosomiasis

Post-translational protein deimination signatures in sea lamprey (<i>Petromyzon marinus</i>) plasma and plasma-extracellular vesicles

Lampreys are a jawless vertebrate species belonging to an ancient vertebrate lineage that diverged from a common ancestor with humans ~500 million years ago. The sea lamprey (Petromyzon marinus) has a filter feeding ammocoete larval stage that metamorphoses into a parasitic adult, feeding both on teleost and elasmobranch fish. Lampreys are a valuable comparative model species for vertebrate immunity and physiology due to their unique phylogenetic position, unusual adaptive immune system, and physiological adaptions such as tolerance to salinity changes and urea. Peptidylarginine deiminases (PADs) are a phylogenetically conserved enzyme family which catalyses post-translational deimination/citrullination in target proteins, enabling proteins to gain new functions (moonlighting). The identification of deiminated protein targets in species across phylogeny may provide novel insights into post-translational regulation of physiological and pathophysiological processes. Extracellular vesicles (EVs) are membrane vesicles released from cells that carry cargos of small molecules and proteins for cellular communication, involved in both normal and pathological processes. The current study identified deimination signatures in proteins of both total plasma and plasma-EVs in sea lamprey and furthermore reports the first characterisation of plasma-EVs in lamprey. EVs were poly-dispersed in the size range of 40-500 nm, similar to what is observed in other taxa, positive for CD63 and Flotillin-1. Plasma-EV morphology was confirmed by transmission electron microscopy. Assessment of deimination/citrullination signatures in lamprey plasma and plasma-EVs, revealed 72 deimination target proteins involved in immunity, metabolism and gene regulation in whole plasma, and 37 target proteins in EVs, whereof 24 were shared targets. Furthermore, the presence of deiminated histone H3, indicative of gene-regulatory mechanisms and also a marker of neutrophil extracellular trap formation (NETosis), was confirmed in lamprey plasma. Functional protein network analysis revealed some differences in KEGG and GO pathways of deiminated proteins in whole plasma compared with plasma-EVs. For example, while common STRING network clusters in plasma and plasma-EVs included Peptide chain elongation, Viral mRNA translation, Glycolysis and gluconeogenesis, STRING network clusters specific for EVs only included: Cellular response to heat stress, Muscle protein and striated muscle thin filament, Nucleosome, Protein processing in endoplasmic reticulum, Nucleosome and histone deacetylase complex. STRING network clusters specific for plasma were: Adipokinetic hormone receptor activity, Fibrinogen alpha/beta chain family, peptidase S1A, Glutathione synthesis and recycling-arginine, Fructose 1,6-bisphosphate metabolic process, Carbon metabolism and lactate dehydrogenase activity, Post-translational protein phosphorylation, Regulation of insulin-like growth factor transport and clotting cascade. Overall, for the EV citrullinome, five STRING network clusters, 10 KEGG pathways, 15 molecular GO pathways and 29 Reactome pathways were identified, compared with nine STRING network clusters, six KEGG pathways, two Molecular GO pathways and one Reactome pathway specific for whole plasma; while further pathways were shared. The reported findings indicate that major pathways relevant for immunity and metabolism are targets of deimination in lamprey plasma and plasma-EVs, with some differences, and may help elucidating roles for the conserved PAD enzyme family in regulation of immune and metabolic function throughout phylogeny

La Tombe d'Arégonde. Nouvelles analyses en laboratoire du mobilier métallique et des restes organiques de la défunte du sarcophage 49 de la basilique de Saint-Denis

Ayant repris en 1957 les fouilles d'Edouard Salin dans le sous-sol de la basilique de Saint-Denis, Michel Fleury mit au jour en 1959 un sarcophage (N° 49) contenant une inhumation féminine exceptionnelle par la qualité de son mobilier funéraire et la conservation des restes organiques correspondant à ses vêtements. Grâce à une bague en or portant le nom ARNEGVNDIS et un monogramme central lu comme REGINE, la défunte fut identifiée à la reine Arégonde, mentionnée par Grégoire de Tours comme l'une des épouses de Clotaire Ier (511-561) et la mère de Chilpéric Ier. Compte tenu de la date de naissance de ce dernier, placée en 539 (en réalité en 534), et d'une estimation anthropologique vers 45 ans de l'âge de décès de la défunte, sa mort fut fixée vers 565/570. Cette datation ne s'accordant pas à celle du mobilier funéraire, sensiblement plus récent, plusieurs chercheurs doutèrent que la défunte ait bien été le personnage historique cité par Grégoire de Tours. La redécouverte récente du squelette de la défunte de la tombe 49 ainsi que des restes organiques végétaux et animaux qui l'accompagnaient, disparus depuis une trentaine d'années, a permis de rouvrir ce dossier. Ainsi, il est désormais acquis que la défunte, âgée de 61 ans (plus ou moins trois ans) est morte vers 580, ce qui correspond mieux à la datation archéologique du mobilier funéraire et donc à l'identification historique de la défunte. Pour sa part, le réexamen des restes organiques met largement en cause la reconstitution du costume d'Arégonde par Michel Fleury et Albert France-Lanord. Enfin, les analyses menées au Centre de Recherche et de Restauration des Musées de France (C2RMF) sur les objets métalliques en or et en argent de la tombe d'Arégonde, ainsi que sur les grenats pouvant les orner, ont considérablement modifié les acquis antérieurs, qu'il s'agisse des alliages utilisés ou de la provenance des grenats

La Tombe d'Arégonde. Nouvelles analyses en laboratoire du mobilier métallique et des restes organiques de la défunte du sarcophage 49 de la basilique de Saint-Denis

Ayant repris en 1957 les fouilles d'Edouard Salin dans le sous-sol de la basilique de Saint-Denis, Michel Fleury mit au jour en 1959 un sarcophage (N° 49) contenant une inhumation féminine exceptionnelle par la qualité de son mobilier funéraire et la conservation des restes organiques correspondant à ses vêtements. Grâce à une bague en or portant le nom ARNEGVNDIS et un monogramme central lu comme REGINE, la défunte fut identifiée à la reine Arégonde, mentionnée par Grégoire de Tours comme l'une des épouses de Clotaire Ier (511-561) et la mère de Chilpéric Ier. Compte tenu de la date de naissance de ce dernier, placée en 539 (en réalité en 534), et d'une estimation anthropologique vers 45 ans de l'âge de décès de la défunte, sa mort fut fixée vers 565/570. Cette datation ne s'accordant pas à celle du mobilier funéraire, sensiblement plus récent, plusieurs chercheurs doutèrent que la défunte ait bien été le personnage historique cité par Grégoire de Tours. La redécouverte récente du squelette de la défunte de la tombe 49 ainsi que des restes organiques végétaux et animaux qui l'accompagnaient, disparus depuis une trentaine d'années, a permis de rouvrir ce dossier. Ainsi, il est désormais acquis que la défunte, âgée de 61 ans (plus ou moins trois ans) est morte vers 580, ce qui correspond mieux à la datation archéologique du mobilier funéraire et donc à l'identification historique de la défunte. Pour sa part, le réexamen des restes organiques met largement en cause la reconstitution du costume d'Arégonde par Michel Fleury et Albert France-Lanord. Enfin, les analyses menées au Centre de Recherche et de Restauration des Musées de France (C2RMF) sur les objets métalliques en or et en argent de la tombe d'Arégonde, ainsi que sur les grenats pouvant les orner, ont considérablement modifié les acquis antérieurs, qu'il s'agisse des alliages utilisés ou de la provenance des grenats