AGN spiral galaxies in groups: effects of bars

AIMS: We explore properties of barred active spiral galaxies in groups and clusters selected from the Sloan Digital Sky Survey data release 7 (SDSS-DR7), with the aim of assessing the effects of bars on active galactic nuclei (AGN) and the role of the high density environment. METHODS: We identified barred active galaxies that reside in groups and clusters by cross-correlating the total barred AGN sample with the SDSS-DR7 group catalog. With the goal of providing a suitable quantification of the effects of bars, a reliable control sample of unbarred active galaxies in high density environments with similar redshift, magnitude, morphology, and bulge size distributions was also constructed. RESULTS: We found that the fraction of barred AGN galaxies in groups and clusters (≈38%) is higher than those in the total barred AGN sample (≈28%), indicating that AGN spiral galaxies in groups are more likely to be barred than those in the field. We also found that barred AGN galaxies are more concentrated towards the group centers than the other unbarred AGN group members. In addition, barred AGN host galaxies show an excess of population dominated by red colors, with respect to the control sample, suggesting that bars produce an important effect on galaxy colors of AGN hosts. The groups of AGN galaxies with and without bars show similar virial masses; however, the host groups of the barred AGN exhibit a larger fraction of red colors than the host groups of the corresponding unbarred active galaxies in the control sample. Color-magnitude relations of both host groups of AGN differ significantly: the host group colors of barred active galaxies display distributions spreading toward red populations, at the same (Mr)Group, with respect to the host groups of the unbarred AGN objects. This trend is more significant in less massive groups than in groups with MVirial> 1013.5M⊙. Barred active galaxies show an excess of nuclear activity compared to galaxies without bars in the control sample. We found that barred active galaxies located farther from the group-center have stronger Lum[OIII], while the nuclear activity in AGN galaxies without bars remain approximately constant with the group-centric distance. In addition, for both AGN samples, nuclear activity increases in bluer host groups however, barred active objects systematically show higher Lum[OIII] values, irrespective of the global group colors. Our findings suggest that the efficiency of bars to transport material towards the more central regions of the AGN galaxies in high density environments reveals an important dependence on the localization of objects within the group/cluster and on the host group colors.Fil: Alonso Giraldes, Maria Sol. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Coldwell Lloveras, Georgina Vanesa. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Garcia Lambas, Diego Rodolfo. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; Argentin

Biología reproductiva de Astragalus gines-lopezii Talavera et al.

Astragalus gines-lopezii Talavera et al. se encuentra incluido en la Lista Roja 2008 en la categoría En Peligro (EN). Es un endemismo de área de distribución muy reducida, que tan solo cuenta con 2 poblaciones y un escaso número de ejemplares (menos que 1000). Con el objetivo de detectar posibles amenazas, hemos estudiado diferentes aspectos de su biología reproductiva: 1.- Capacidad de producir semillas viables. De 50 individuos hemos contamos, in situ, el nº de inflorescencias y el nº de flores de cada una. Posteriormente colectamos las legumbres maduras y contamos, medimos y pesamos sus semillas. En laboratorio realizamos ensayos de germinación 2.- Análisis de la capacidad germinativa de la especie en su conjunto y de cada una de sus poblaciones Las semillas se incubaron a las Tas alternas 25/15ºC, fotoperiodo de 16 h/luz y 8/oscuridad. Unas, sin ningún tratamiento previo, alcanzaron porcentajes de germinación entre 0 % y 60 %, según los diferentes individuos; sin embargo, las escarificadas alcanzaron porcentajes finales entre 60 y 100 %. En conclusión, se puede afirmar que las semillas de Astragalus gines-lopezii presentan dormición física debida a su cubierta dura e impermeable al agua. En condiciones naturales, el progresivo desgaste de la cubierta seminal por diversos factores (erosión, microorganismos, variación de temperaturas, etc.) permiten la germinación de las semillas de esta especie de forma gradual

Census, reproductive biology, and germination of Astragalus gines-lopezii (Fabaceae),a narrow and endangered endemic species of SW Spain.

Astragalus gines-lopezii Talavera, Podlech, Devesa & F.M.Vazquez (Fabaceae) is a threatened endemic species with a distribution restricted to a very small area in Badajoz Province (Extremadura Region, SW Spain) and only 2 populations are known.This species was catalogued in the "Endangered" category in the 2008 Red List and the 2010 Threatened Spanish Vascular Flora List. Despite its status as an endangered species, at present very little is known about the distribution, census, and reproductive biology of this species. In this study we have carried out anexhaustive census of A. gines-lopezii, and we have evaluated the production of flowers, fruits, and seeds and the existence or not of intra- and interpopulation variability in seed germination. Results have highlighted the high reproductive capacity of this species on the basis of a high production of flowers, fruits, and seeds. Mechanical scarification of seeds was effective for increasing germination. Thus, initial germination (22%-60%) was increased to 97%-99% when seeds were rubbed with sandpapers. A high intra- and interpopulation variability in seed germination was found in this species. A. gines-lopezii produces seeds with different degrees of physical dormancy, varying this grade among different individuals within a population

Evaluation of reproductive success in Senecio coincyi Rouy, a threatened species from Spain

Senecio coincyi Rouy (Asteraceae) is a threatened endemic species from the mountains of Sierra de Gredos, centraf western Spain. This species is protected by the Autonomous Community of Castile and León (Spain) and is included in the "In danger of extinction" category in the protected flora catalogue of that region. It was later catalogued as Vulnerable (VU) on the Red List of Threatened Spanish Vascular Flora (Moreno et al., 2008). In this paper, the results of a two-year investigation of S. coincyi population biology are shown. The aim of this work was to study several aspects of S. coincyi reproductive biology

Seed production and germination of the endangered species Astragalus gines-lopezii

Astragalus gines-lopeziiTalavera era/. {Fabaceae} is an endemic species from southwest Spain with a very limited area of distribution. There are only two known populations of this species, totaling less than 1000 individuals. This species was included on the Red List of Threatened Spanish Vascular Flora in 2008 in the category Endangered (EN) (Moreno 2008). The restricted area of distribution, limited number of individuals and their population structure could represent a high risk for survival of this species. Therefore, in order to detect potential threats, we have studied some key aspects of its reproductive biology. Fructification success and seed production were evaluated, and morphological and physiological seed variability were also studied

On the relation between Seyfert 2 accretion rate and environment at z < 0.1

We analyse different properties of the small-scale environment of Seyfert 2 for two samples selected according to the accretion rate parameter, R, from the Sloan Digital Sky Survey, Data Release 7 survey. We compare the results with two control samples of non-active galaxies that cover the same redshift range, luminosity, colours, morphology, age and stellar mass content. Our study shows that both high and low accretion rate subsamples reside in bluer and lower density environments than the control samples. However, we find that this difference is at least two times stronger for the low accretion rate Seyferts. In the vicinity of Seyfert 2, red galaxies have systematically lower values of stellar mass as compared with corresponding control samples. The lower values of stellar mass for red neighbours is more significant at higher density environments and it is more evident for low accretion rate Seyfert. We also find that this effect is independent of the host's stellar mass. Our results are consistent with a scenario where active galactic nucleus occurrence is higher in lower/medium density environments with a higher merger rate and a lack of a dense intergalactic medium (that can strip gas from these systems) that provide suitable conditions for the central black hole feeding. We find this particularly evident for the low accretion rate Seyferts that could compensate through the intergalactic medium the lack of gas of their hosts.Fil: Coldwell Lloveras, Georgina Vanesa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Instituto de Ciencias Astronómicas, de la Tierra y del Espacio. Universidad Nacional de San Juan. Instituto de Ciencias Astronómicas, de la Tierra y del Espacio; Argentina. Universidad Nacional de San Juan; ArgentinaFil: Gurovich, Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; ArgentinaFil: Diaz Tello, Jorge Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; ArgentinaFil: Söchting, Ilona K.. University of Oxford; Reino UnidoFil: Garcia Lambas, Diego Rodolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; Argentin

Is it appropriate protective figure "Plant Micro-Reserves" to protect tree species? The example of Betula pendula subsp. fontqueri in "La Garganta de los Caballeros" (Ávila)

The figure of protection "micro-reserves" was created in the Region of Valencia (ANONYMOUS, 1994) with the aim of protecting endangered plant species. This is one of the areas of greatest floristic richness and uniqueness of the western Mediterranean. In this area rare, endemic or threatened vascular flora has a peculiar distribution: they appear to form small fragments spread over the entire region (LAGUNA, 1994; LAGUNA, 2001) The protection of every these small populations of great scientific value has significant challenges. It doesn´t try to protect every species that set out in Annex IV of the by then existing Law 4 / 1989 (repealed in 2007), or to protect to the most ecological level with the creation of Natural Protected Area but an intermediate level: the plant community of small size. According to the decree: “as Micro-Reserve will be declared the natural parcels of land under 20 hectares that contain a high concentration of rare plants, endemic, threatened or of high scientific interest” (ANONYMOUS, 1994) . Of course, the statement of an area as micro-reserve carries certain prohibitions that are harmful to the vegetal communit

Evidència de forçament climàtic natural i antròpic durant l'últim mil·lenni

Unidad de excelencia María de Maeztu MdM-2015-0552Un equip d'investigació multidisciplinar ha aconseguit un avanç important en el coneixement de les respostes terrestres i oceàniques a la variabilitat climàtica durant l'últim mil·lenni, incloent l'era industrial. Dos registres marins recuperats a la conca de la mar d'Alboran i analitzats a molt alta resolució han permès la reconstrucció de les condicions climàtiques i oceanogràfiques, així com la identificació d'influència antròpica a la regió més occidental de la Mediterrània durant aquest període de temps.A multidisciplinary international team has advanced in the understanding of the terrestrial and ocean responses to climate variability in the western Mediterranean during the past millennium including the industrial era. Two high-resolution deep-sea records from the Alboran Sea basin enabled the reconstruction of climate and oceanographic conditions as well as the identification of human fingerprints during this period

Caracterización ecológica de Astragalus gines-lopezii, un endemismo extremeño En Peligro (EN, LR2008)

Astragalus gines-lopezii Talavera et al. es un endemismo de la provincia de Badajoz que cuenta con menos de 1000 ejemplares en 2 poblaciones: la más importante está en la Sª de Mª Andrés, en un matorral dominado por Cistus albidus, con Genista hirsuta, Cistus monspeliensis, Teucrium gr. polium, Retama sphaerocarpa, Quercus coccifera, etc. y pies dispersos de encina (Quercus ilex ssp. ballota) y acebuches (Olea europaea var. sylvestris). La población de la Sª Calera, se encuentra en medios más antropizados: en un olivar y como ruderal. Los sustratos presentan pH en agua claramente básicos (entre 7,9 y 8,37) y en KCl oscila entre 7,3 y 7,6; ligados a unos contenidos significativos de carbonatos procedentes de rocas calizas compactas cuasi marmóreas. También destacan los contenidos de materia orgánica (entre 1,33 % y 3,56 %,) así como unos valores de nitrógeno total entre 0,31% y 0,15%. Se trata por tanto de suelos con altas tasas de descomposición de la materia orgánica (C/N ¿ 8). Desde el punto de vista físico presentan significativos contenidos de elementos gruesos (% elementos mayor que 2 mm ¿ 48 ) y con texturas en las que tiende a predominar la fracción limosa (% limo ¿ 50) Clima. La precipitación total anual oscila entre 754 y 650 mm y la temperatura media anual entre 16,2 y 15,3 ºC. Las medias de las máximas del mes más cálido 33,9 y las mínimas del mes más frío 3,48 º

Modelado, análisis y control dinámico de un reformador de etanol en tres etapas para aplicaciones en pilas de combustible

This thesis presents results related to the design, modeling and control of a low temperature ethanol reformer as a source of hydrogen designed to feed a fuel cell (PEMFC). As fuel, ethanol has been selected as one of the renewable energy sources currently under study due to its interest for scientific and economic fields. The reformer has been separated into three stages in order to guarantee the maximum production of H2 and the minimum production of CO. SnO2 and Co(Fe)Na+/ZnO catalytic monoliths have been used, where in the first stage ethanol is dehydrogenated over SnO2 and, in the second stage, the reforming of acetaldehyde over Co(Fe)Na+/ZnO takes place under the presence of hydrogen, generated in stage 1. Then we add a third stage with a Fe2O3-Cr2O3 commercial catalyst to complete the WGS reaction. In addition to ensure a reducing environment in the reforming step, this configuration also allows optimizing the conditions of each stage of the reaction. Constant pressure has been imposed as a condition of the reformer design, but the variation of temperatures in each stage has been considered. In this thesis dynamic models have been developed for the reformer of ethanol with vapour at low temperatures described previously, the stationary and dynamic response has been analysed and controllers have been designed to meet the requirements of the system. Up until now there have only been a few works that address the design and implementation of controllers for fuel reformers, and none of these have used ethanol fuel. Some are in the area of automatic control and have been applied to tubular reformers but consider other type of fuel, not ethanol, for its alimentation In this thesis the mathematical model used to represent the state of the monolithic reformer has been presented, considered and implemented. Through a study of the stationary state one can validate the different hypothesis of assumed design and through an analysis of the parametric sensitivity the operational conditions for the reform process are discussed. This way the mathematic model of the reactor can be used to explore other alternatives for the operation of the reformer putting an emphasis on the influence of temperature in the second stage as this is a variable. Afterwards a study is made of the control of the models based on the balance of mass and linearised energy. In order to realise the control study the mathematic tools RGA, MRI and CN have been used. Through this analysis the control structures have been selected which will be most suitable for design controllers which can guarantee the requirements for the fuel cell