Productos de alfarería de Cerro Macareno, Sevilla : naturaleza y procedencia de las ánforas y otros objetos cerámicos. Siglos VIII al III a. J.C.

Son muchos los métodos empleados para el estudio de las arcillas y de los productos cerámicos, contribuyendo de distinta manera, aunque complementaria, en el conocimiento de la composición, procedencia de los materiales, tecnología empleada en su elaboración y en general en todos aquellos procesos que se pudieron seguir en la tibricación del objeto cerámico. Estos métodos pueden ser, bien destructivos, aunque utilizando cantidades muy pequeñas de muestra, o bien no destructivos, cada vez más empleados en la investigación moderna. En el estudio de los materiales cerámicos, bien sea el soporte, o bien sea la pintura que ha servido para decorarlo, se emplea el análisisq\límico tradicional cualitativo y cuantitativo. Para este último se emplea cada \leimás la técnica de la absorción atómica. Asimismo, se emplean los siguientes métodos de análisis por vía física: La espectroscopía de emisión en el ultravioleta, que permite obtener un espectro de emisión en el que la parte más frecuentemente utilizada se sitúa entre 200 y 400 nm (ultravioleta). La espectrometría de fluorescencia de rayos X es una técnica desde hace tiempo utilizada. El método tiene poca sensibilidad para elementos tales como el cobre, níquel, cinc o hierro, a causa del «ruido de fondo» que el mismo aparato emite. La microfluorescencia permite operar directamente sobre una capa de pintura y su análisis no es destructivo. La microsonda electrónica es una aplicación de los principios y de la técnica de la espectrografía de emisión de rayos X. Su poder separador es infinitamente superior al del mejor instrumento óptico. La activación por neutrones, que precisa de una fuente generadora de estas radiaciones (pila atómica), es, por tanto, de muy difícil empleo. En España se utiliza la pila atómica de la Junta de Energía Nuclear. Este análisis permite determinar los elementos mayores, menores y trazas existentes en los objetos cerámicos y en los pigmentos. Es de un gran interés para conocer la procedencia de los materiales empleados, detectando el posible o posibles yacimientos de las arcillas utilizadas. La difracción de rayos X determina la estructura cristalina de los elementos y compuestos químicos ya sean orgánicos o inorgánicos, si bien la técnica no es válida para los compuestos amorfos. Para el estudio de aquellos materiales en los que la pintura se encuentre unida al soporte mediante lacas, gomas o barnices se emplean métodos de absorción en el infrarrojo, así como la cromatografía en fase gaseosa. Los métodos seguidos que se enumeran en el siguiente apartado nos han permitido identificar la procedencia y naturaleza de las arcillas utilizadas en los objetos cerámicos objeto de este estudio.Peer reviewe

Materias primas y datos tecnológicos de piezas cerámicas antiguas del yacimiento arqueológico de Cerro Macareno (Sevilla)

14 páginas, 5 figuras, 7 tablas, 7 referencias.[EN]: A study of twenty eight fragments of amphoras from the archaeological bed of Cerro Macareno (Sevilla) has been done by chemical, physicochemical, X-ray diffraction and thermal methods, in order to establish the nature and provenance of the raw materials and the technological aspects of their fabrication. All the data lead to the conclusion that four of the pieces were probably imported from the Palestine-Phoenicie; the rest were made out of raw materials from the surrounding areas of Cerro Macareno. Most of the pieces were fired below 700°C, only four of them at about 700-750°C, and the other seven, probably from 800-850°C.[ES]: Se estudian la composición química y mineralógica, contenido en determinados elementos escasos, materias primas y temperaturas probables de cocción empleadas en la fabricación de un conjunto de 25 fragmentos de ánforas del yacimiento arqueológico de Cerro Macareno (Sevilla). Los métodos empleados fueron análisis químico, difracción de rayos-X, A.T.D., análisis por activación neutrónica y pruebas de cocción intermitente por calentamiento de cien en cien grados, desde 400° a 1.100° C seguido en cada caso de estudios por difracción de rayos-X y de observación de los cambios de color y aspecto de los cortes de las piezas. De todo ello se concluye que cuatro de las piezas estudiadas son de origen importado (Palesti-na-Fenicia), estando fabricadas las restantes con materiales procedentes de los aluviones del Guadalquivir, en las inmediaciones del Cerro Macareno. Del total de las piezas, 17 se cocieron probablemente a temperaturas inferiores a 700°C, cuatro a 700-750° C y siete a 800-850°C.Peer reviewe

Histone Mutants Separate R Loop Formation from Genome Instability Induction

R loops have positive physiological roles, but they can also be deleterious by causing genome instability, and the mechanisms for this are unknown. Here we identified yeast histone H3 and H4 mutations that facilitate R loops but do not cause instability. R loops containing single-stranded DNA (ssDNA), versus RNA-DNA hybrids alone, were demonstrated using ssDNA-specific human AID and bisulfite. Notably, they are similar size regardless of whether or not they induce genome instability. Contrary to mutants causing R loop-mediated instability, these histone mutants do not accumulate H3 serine-10 phosphate (H3S10-P). We propose a two-step mechanism in which, first, an altered chromatin facilitates R loops, and second, chromatin is modified, including H3S10-P, as a requisite for compromising genome integrity. Consistently, these histone mutations suppress the high H3S10 phosphorylation and genomic instability of hpr1 and sen1 mutants. Therefore, contrary to what was previously believed, R loops do not cause genome instability by themselves.European Research Council ERC2014 AdG669898Ministerio de Economía y Competitividad BFU2013-42918-P, BFU2016-75058-

Generation of rotationally dominated galaxies by mergers of pressure-supported progenitors

Through the analysis of a set of numerical simulations of major mergers between initially non-rotating, pressure supported progenitor galaxies with a range of central mass concentrations, we have shown that: (1) it is possible to generate elliptical-like galaxies, with v/sigma > 1 outside one effective radius, as a result of the conversion of orbital- into internal-angular momentum; (2) the outer regions acquire part of the angular momentum first; (3) both the baryonic and the dark matter components of the remnant galaxy acquire part of the angular momentum, the relative fractions depend on the initial concentration of the merging galaxies. For this conversion to occur the initial baryonic component must be sufficiently dense and/or the encounter should take place on a orbit with high angular momentum. Systems with these hybrid properties have been recently observed through a combination of stellar absorption lines and planetary nebulae for kinematic studies of early-type galaxies. Our results are in qualitative agreement with such observations and demonstrate that even mergers composed of non-rotating, pressure-supported progenitor galaxies can produce early-type galaxies with significant rotation at large radii.Comment: 5 pages, 6 figures, 2 tables. Accepted for publication in A&A Letter

Predictability of the resonance frequency analysis in the survival of dental implants placed in the anterior non-atrophied edentulous mandible

Background: Dental primary implant stability is considered essential in the success of the osseointegration process. The recent advent of the resonance frequency analysis (RFA) seems to effectively measure primary implant stability, although its relationship with implant survival has to be further established. Patients and Methods: Seventy patients with complete mandibular edentulism underwent dental implant rehabilitation by means of the placement of 68 dental implants within the interforaminal region and subsequent placement of an overdenture. Primary implant stability was measured by means of RFA and it was expressed in terms of implant stability quotient (ISQ) on the day of the implant insertion and at the time of the healing abutment placement in a conventional implant two-stage surgical procedure. Results: Overall implant survival rate was 97.1% at the end of the follow-up period. The mean ISQ value for 3.75 and 4.25 mm diameter implants was 78.4 ± 5.46 and 80.83 ± 5.35 respectively, at the time of the implant placement; and 76.68 ± 4.34 and 78.22 ± 6.87 respectively, at the second surgical stage. No statistical differences were observed in relation to changes in mean ISQ value along the healing process Conclusions: No statistical differences in terms of primary and secondary implant stability measured by RFA exists between 3.75 mm and 4.25 mm diameter implants in the conventional implant two-stage surgical procedure in patients with non-atrophied edentulous mandible being restored with an overdenture. Furthermore, no statistical association between RFA and the implant insertion torque was observed for endosseous dental implant placement at the first surgical stage. © Medicina Oral

Las imágenes de la historia en la obra de Stanley Kubrick.

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The names of southwestern european goats: Is iberian ibex the best common name for capra pyrenaica?

The names of southwestern European goats: is Iberian ibex the best common name for Capra pyrenaica? The common name designated to a species is important because it connects specialists with non–experts. The matter of the correct common name is relevant to the conservation and management of conspicuous or flag species. The English name "Spanish ibex" to designate Capra pyrenaica is extensive in the scientific literature, and some have defended its appropriateness. However, in our opinion, it is not the best term to designate this species. We propose that "Iberian wild goat" should be used. Herein, we review the etymology, history, taxonomy and public use of the names used to designate goats (domestic and wild) in southwestern Europe during the last two millennia. Used first by Pliny the Elder, the name "ibex" has been applied most often for the Alpine wild goat (C. ibex), and few authors applied this name to C. pyrenaica until the 20th century when some influential works extended its use in the scientific literature. Adult males of C. pyrenaica have lyre–shaped, and typically smooth horns that do not match the ibex morphotype, which has scimitar–shaped knotted horns. Although C. pyrenaica and C. ibex are probably phylogenetically close, their common names do not necessarily have to match. The rules of common names differ from those of scientific names. Cabra montés or cabra brava (wild goat) is the common name used by most authors in the Iberian peninsula. This name is deeply entrenched in the Iberian languages and has been used since the earliest references to the species in mediaeval times. We propose the adoption of "Iberian wild goat" for legal and scientific communication and when interacting with the media