Isolated elliptical galaxies in the local Universe

We have studied a sample of 89 very isolated, elliptical galaxies at z < 0.08 and compared their properties with elliptical galaxies located in a high-density environment such as the Coma supercluster. Our aim is to probe the role of environment on the morphological transformation and quenching of elliptical galaxies as a function of mass. In addition, we elucidate the nature of a particular set of blue and star-forming isolated ellipticals identified here. We study physical properties of ellipticals such as color, specific star formation rate, galaxy size, and stellar age, as a function of stellar mass and environment based on SDSS data. We analyze the blue star-forming isolated ellipticals in more detail, through photometric characterization using GALFIT, and infer their star formation history using STARLIGHT. Among the isolated ellipticals ~ 20% are blue, 8% are star forming, and ~ 10% are recently quenched, while among the Coma ellipticals ~ 8% are blue and just <= 1% are star forming or recently quenched. There are four isolated galaxies (~ 4.5%) that are blue and star forming at the same time. These galaxies, with masses between 7 x 10^9 and 2 x 10^10 h-2 M_sun, are also the youngest galaxies with light-weighted stellar ages <= 1 Gyr and exhibit bluer colors toward the galaxy center. Around 30-60% of their present-day luminosity, but only < 5% of their present-day mass, is due to star formation in the last 1 Gyr. The processes of morphological transformation and quenching seem to be in general independent of environment since most of elliptical galaxies are 'red and dead', although the transition to the red sequence should be faster for isolated ellipticals. In some cases, the isolated environment seems to propitiate the rejuvenation of ellipticals by recent (< 1 Gyr) cold gas accretion.Comment: 23 pages, 15 figures (16 pages and 9 figures without appendices). A&A, in pres

Mid Holocene paludal deposits in the littoral plains of the Ter River (Baix Empordà, Girona)

Se analiza un conjunto de materiales palustres situados en la zona de contacto entre el corredor de Palafrugell y la llanura litoral del río Ter (Baix Ter), relacionados con un sistema de derrame de aguas surgentes ricas en carbonato cálcico. Las secuencias estudiadas se caracterizan por la presencia de un nivel de lutitas negruzcas con abundante malacofauna. El registro malacológico incluye especies propias de medios acuáticos de aguas tranquilas y de ambientes terrestres húmedos. Aparecen también algunas especies terrestres características de medios abiertos y secos que denotan las condiciones ambientales de las áreas circundantes a las zonas pantanosas. Las dataciones 14C fechan estos materiales en ca. 7.000 a. BP, por lo que se inscriben dentro de la fase holocena de relleno de la depresión del Baix Ter. Los coluviones que recubren los sedimentos palustres presentan una malacofauna terrestre, típica de ambientes abiertos y secos, idéntica a la que coloniza hoy en día la llanura del Empordà.The paludal deposits presented here belong to a geomorphological unit identified between Palafrugell Corridor and the littoral plains of Ter River (Baix Ter), associated to a carbonate-rich spring system. The sections show a distintic clay level, mixed with black silts, very rich in snail remains. The malacological assemblage contained stillwaters species (Bithynia leachii, Galba truncatula, Pisidium milium, Radix peregra) along with damp species (Monacha cartusiana, Oxyloma elegans, Succinea putris, Succinella oblonga, Vallonia pulchella, Vertigo sp.). Some open-dry species are also present (Cernuella virgata, Eobania vermiculata, Pomatias elegans, Rumina decollata) revailing a mosaic-like landscape. Radiocarbon dates place this level ca. 7.000BPwithin the Holocene sequence of the Baix Ter basin. Colluvial deposits on top of these paludal levels have a typical open-dry malacological assemblage (Cernuella virgata, Cochlicella acuta, Eobania vermiculata, Pomatias elegans, Rumina decollata, Trochoidea ele - gans) the same assemblage that inhabits the Empordà littoral plains nowadays

Invirtiendo en capital natural: un marco para integrar la sostenibilidad ambiental en las políticas de cooperación

Tomando en cuenta la magnitud de la crisis ambiental que afecta al planeta y los estrechos vínculos existentes entre la conservación de los ecosistemas y la lucha contra la pobreza, cabría preguntarse por qué los temas de protección del medio ambiente continúan teniendo un peso relativo tan bajo en las agendas y prioridades de las agencias de cooperación internacional. En este artículo, se analizan las razones de este desequilibrio y se propone un marco conceptual con base socio-ecológica para facilitar una verdadera integración de la sostenibilidad ambiental como prioridad estratégica en las políticas y herramientas de ayuda oficial al desarrollo. Varios paradigmas y principios fundamentales emanan de este nuevo marco conceptual, que considera a los ecosistemas funcionales como un capital natural que, adecuadamente gestionado, es capaz de producir un rico y variado flujo de servicios sobre los cuales es posible construir un proceso de desarrollo social, económica y ambientalmente sostenible, además de justo en términos de equidad intra e intergeneracional

Solution landscapes in nematic microfluidics

We study the static equilibria of a simplified Leslie–Ericksen model for a unidirectional uniaxial nematic flow in a prototype microfluidic channel, as a function of the pressure gradient G and inverse anchoring strength, B. We numerically find multiple static equilibria for admissible pairs (G,B) and classify them according to their winding numbers and stability. The case G=0 is analytically tractable and we numerically study how the solution landscape is transformed as G increases. We study the one-dimensional dynamical model, the sensitivity of the dynamic solutions to initial conditions and the rate of change of G and B. We provide a physically interesting example of how the time delay between the applications of G and B can determine the selection of the final steady state

Decision-making tools to manage the microbiology of drinking water distribution systems

This paper uses a two-fold multi-criteria decision-making (MCDM) approach applied for the first time to the field of microbial management of drinking water distribution systems (DWDS). Specifically, the decision-making trial and evaluation laboratory (DEMATEL) was applied removing the need for reliance on expert judgement, and analysed interdependencies among water quality parameters and microbiological characteristics of DWDS composed of different pipe materials. In addition, the fuzzy technique for order preference by similarity to ideal solution (FTOPSIS) ranked the most common bacteria identified during trials in a DWDS according to their relative abundance while managing vagueness affecting the measurements. The novel integrated approach presented and proven here for an initial real world data set provides new insights in the interdependence of environmental conditions and microbial populations. Specifically, the application shows as the bacteria having associated the most significant microbial impact may not be the most abundant. This offers the potential for integrated management strategies to promote favourable microbial conditions to help safeguard drinking water quality

Seyfert's Sextet: A Slowly Dissolving Stephan's Quintet?

We present a multiwavelength study of the highly evolved compact galaxy group known as Seyfert's Sextet (HCG79: SS). We interpret SS as a 2-3 Gyr more evolved analog of Stephan's Quintet (HCG92: SQ). We postulate that SS formed by sequential acquisition of 4-5 primarily late-type field galaxies. Four of the five galaxies show an early-type morphology which is likely the result of secular evolution driven by gas stripping. Stellar stripping has produced a massive/luminous halo and embedded galaxies that are overluminous for their size. These are interpreted as remnant bulges of the accreted spirals. H79d could be interpreted as the most recent intruder being the only galaxy with an intact ISM and uncertain evidence for tidal perturbation. In addition to stripping activity we find evidence for past accretion events. H79b (NGC6027) shows a strong counter-rotating emission line component interpreted as an accreted dwarf spiral. H79a shows evidence for an infalling component of gas representing feedback or possible cross fueling by H79d. The biggest challenge to this scenario involves the low gas fraction in the group. If SS formed from normal field spirals then much of the gas is missing. Finally, despite its advanced stage of evolution, we find no evidence for major mergers and infer that SS (and SQ) are telling us that such groups coalesce via slow dissolution.Comment: 70 pages, 19 figures, 15 tables - accepted for publication in the Astronomical Journa