Catalogue of the morphological features in the Spitzer Survey of Stellar Structure in Galaxies (S4^4G)

A catalogue of the morphological features for the complete Spitzer Survey of Stellar Structure in Galaxies (S$^4$G), including 2352 nearby galaxies, is presented. The measurements are made using 3.6 $\mu$m images, largely tracing the old stellar population; at this wavelength the effects of dust are also minimal. The measured features are the sizes, ellipticities, and orientations of bars, rings, ringlenses, and lenses. Measured in a similar manner are also barlenses (lens-like structures embedded in the bars), which are not lenses in the usual sense, being rather the more face-on counterparts of the boxy/peanut structures in the edge-on view. In addition, pitch angles of spiral arm segments are measured for those galaxies where they can be reliably traced. More than one pitch angle may appear for a single galaxy. All measurements are made in a human-supervised manner so that attention is paid to each galaxy. We used isophotal analysis, unsharp masking, and fitting ellipses to measured structures. We find that the sizes of the inner rings and lenses normalized to barlength correlate with the galaxy mass: the normalized sizes increase toward the less massive galaxies; it has been suggested that this is related to the larger dark matter content in the bar region in these systems. Bars in the low mass galaxies are also less concentrated, likely to be connected to the mass cut-off in the appearance of the nuclear rings and lenses. We also show observational evidence that barlenses indeed form part of the bar, and that a large fraction of the inner lenses in the non-barred galaxies could be former barlenses in which the thin outer bar component has dissolved.Comment: 17 pages, 12 figures, accepted for publication in A&

Isocausal spacetimes may have different causal boundaries

We construct an example which shows that two isocausal spacetimes, in the sense introduced by Garc\'ia-Parrado and Senovilla, may have c-boundaries which are not equal (more precisely, not equivalent, as no bijection between the completions can preserve all the binary relations induced by causality). This example also suggests that isocausality can be useful for the understanding and computation of the c-boundary.Comment: Minor modifications, including the title, which matches now with the published version. 12 pages, 3 figure

The breed concept. A epistemological approach

It is realized an approximation of the knowledge of a breed"s notion, revising its causality and the aspects that affect its conceptualization. For this, the breed’s taxonomical position and its relation with the other levels is studied, the principal anthropogenic and natural mechanisms are analyzed which, from the primitive wild substrates, generated the domestic breeds which are understood today. Lastly, when considering the processes that led to formation, their acceptance and the definitions that the different authors have made, it is considered as the best definition the following: The breeds are populations that are distinguished by a group of exteriorly visible characters, which are genetically determined and that have differentiated from others of the same species throughout the historical process, taking into account that these have originated and localized in a determined area with a common environment.Realizamos una aproximación al conocimiento de la noción de raza, revisando su causalidad y los aspectos que afectan a su conceptualización. Para ello, se estudia la posición taxonómica de la raza y su relación con los otros niveles, se analizan los principales mecanismos antropógenos y naturales que, desde los substratos primitivos salvajes, generaron a las razas domésticas tal como hoy día se entienden. Por último, ante la observación de los procesos que llevaron a la formación y al reconocimiento de las mismas y ante las definiciones que los diferentes autores han dado, se considera como la definición más adecuada la siguiente: Las razas son poblaciones que se distinguen por un conjunto de caracteres visibles exteriormente, que están determinados genéticamente y que se han diferenciado de otras de la misma especie a lo largo de proceso histórico, teniendo en cuenta que se han originado y localizado en un área determinada con un ambiente común

Invisible floral larcenies: microbial communities degrade floral nectar of bumble bee-pollinated plants

8 páginas, 4 figuras, 1 láminaThe ecology of nectarivorous microbial communities remains virtually unknown, which precludes elucidating whether these organisms play some role in plant–pollinator mutualisms beyond minor commensalism. We simultaneously assessed microbial abundance and nectar composition at the individual nectary level in flowers of three southern Spanish bumble bee-pollinated plants (Helleborus foetidus, Aquilegia vulgaris, and Aquilegia pyrenaica cazorlensis). Yeasts were frequent and abundant in nectar of all species, and variation in yeast density was correlated with drastic changes in nectar sugar concentration and composition. Yeast communities built up in nectar from early to late floral stages, at which time all nectaries contained yeasts, often at densities between 104 and 105 cells/mm3. Total sugar concentration and percentage sucrose declined, and percentage fructose increased, with increasing density of yeast cells in nectar. Among-nectary variation in microbial density accounted for 65% (H. foetidus and A. vulgaris) and 35% (A. p. cazorlensis) of intraspecific variance in nectar sugar composition, and 60% (H. foetidus) and 38% (A. vulgaris) of variance in nectar concentration. Our results provide compelling evidence that nectar microbial communities can have detrimental effects on plants and/or pollinators via extensive nectar degradation and also call for a more careful interpretation of nectar traits in the future, if uncontrolled for yeasts.Work was supported by grants 2005-RNM-156 (Consejería de Innovación, Ciencia y Empresa, Junta de Andalucía) and by CGL2006-01355 and EXPLORA CGL2007-28866-E/BOS (Ministerio de Educación y Ciencia, Gobierno de España).Peer reviewe

La polémica sobre la ubicación del altar mayor de la catedral de México y la adopción del tabernáculo-ciprés exento

La construcción de la catedral de México, en su mayor parte finalizada en 1667, dio lugar a una interesante polémica sobre el espacio idóneo para ubicar su altar mayor: en el crucero o en la cabecera, en línea esta segunda opción con las catedrales españolas. Finalmente, las autoridades eclesiásticas se inclinaron por el procedimiento tradicional, si bien, en lugar de retablo adosado al muro, se optó por un original tabernáculo eucarístico, que siguió la costumbre de algunas catedrales peninsulares construidas a partir del XVI, como la de Granada y la de Málaga. La opinión de dos importantes arquitectos cortesanos, activos en Madrid, como fueron el hermano Francisco Bautista y Sebastián de Herrera Barnuevo, resultaría determinante. El maestro Antonio Maldonado se encargaría de la construcción del tabernáculo, que resultó transformado en el siglo XVIII y desapareció finalmente a mediados del siglo XIX.A Mexico’s cathedral construction, mostly completed in bstract r1667, led to an interesting debate about the main altar ideal location: in the transept or near the apse, in accordance with the spanish cathedrals. Finally, the ecclesiastical authorities preferred the traditional method, but instead of the attached altar to the wall, they opted for an original eucharistic exempt tabernacle, which followed the tradition of some spanish cathedrals built from the sixteenth century on, like those located in Granada and Malaga. The opinion of two courtiers and important architects, active in Madrid, as brother Francisco Bautista and Sebastián de Herrera Barnuevo, was decisive.The designer and tabernacle builder was the wood carver and assembler Antonio Maldonado. During the eighteenth century the tabernacle was transformed and finally, in the mid-nineteenth century it disappeared

Sobre el origen de las razas caprinas españolas

Aún hoy, transcurridos más de 50 años desde que Aparicio Sánchez estableciera el origen de las razas caprinas españolas, su hipótesis está llena de contenido y actualidad. Las tres formas prehistóricas propuestas por este autor como troncos originarios, la Capra Prisca, la Capra Aegagrus y otra forma desconocida de procedencia africana son asumidas, así como las variedades Alpina y Pirenaica de la cabra Aegagrus anteriormente reconocida por Sanson (1903) y que fueron desarrolladas por este autor para el ámbito español. En este trabajo, matizamos las convergencias y divergencias con los autores antes mencionados, se reconoce al Íbice africano como posible forma prehistórica que intervino en la formación del sustrato a partir del cual se formaron nuestras razas y añadimos los posibles orígenes de razas actuales que no estaban caracterizadas ni reconocidas hace 50 años (Verata, Retinta Cacereña, Florida, Canaria, etc), si bien aún, no es posible determinar los orígenes de algunas de ellas ante los escasos conocimientos que se tienen de sus caracteres étnicos