Uncertainties in gas kinematics arising from stellar continuum modelling in integral field spectroscopy data: the case of NGC2906 observed with MUSE/VLT

We study how the use of several stellar subtraction methods and line fitting approaches can affect the derivation of the main kinematic parameters (velocity and velocity dispersion fields) of the ionized gas component. The target of this work is the nearby galaxy NGC 2906, observed with the MUSE instrument at Very Large Telescope. A sample of twelve spectra is selected from the inner (nucleus) and outer (spiral arms) regions, characterized by different ionization mechanisms. We compare three different methods to subtract the stellar continuum (FIT3D, STARLIGHT and pPXF), combined with one of the following stellar libraries: MILES, STELIB and GRANADA+MILES. The choice of the stellar subtraction method is the most important ingredient affecting the derivation of the gas kinematics, followed by the choice of the stellar library and by the line fitting approach. In our data, typical uncertainties in the observed wavelength and width of the H\alpha and [NII] lines are of the order of _rms \sim 0.1\AA\ and _rms \sim 0.2\AA\ (\sim 5 and 10km/s, respectively). The results obtained from the [NII] line seem to be slightly more robust, as it is less affected by stellar absorption than H\alpha. All methods considered yield statistically consistent measurements once a mean systemic contribution \Delta\bar\lambda=\Delta\bar\sigma=0.2xDelta_{MUSE} is added in quadrature to the line fitting errors, where \Delta_{MUSE} = 1.1\AA\ \sim 50 km/s denotes the instrumental resolution of the MUSE spectra. Although the subtraction of the stellar continuum is critical in order to recover line fluxes, any method (including none) can be used in order to measure the gas kinematics, as long as an additional component of 0.2 x Delta_MUSE is added to the error budget.Comment: 20 pages, 14 figure

Improved wear performance of ultra high molecular weight polyethylene coated with hydrogenated diamond like carbon

Hydrogenated diamond like carbon (DLCH) thin films were deposited on medical grade ultra high molecular weight polyethylene (UHMWPE) by radio frequency plasma enhanced chemical vapor deposition. The DLCH coating thicknesses ranged from 250 to 700. nm. The substrates were disks made of UHMWPEs typically used for soft components in artificial joints, namely virgin GUR 1050 and highly crosslinked (gamma irradiated in air to 100. kGy) UHMWPEs. Mechanical and tribological properties under bovine serum lubrication at body temperature were assessed on coated and uncoated polyethylenes by means of nano-hardness and ball-on-disk tests, respectively. Morphological features of the worn surfaces were obtained by confocal microscopy and scanning electron microscopy. This study confirms an increase in surface hardness and good wear resistance for coated materials after 24. h of sliding test compared to uncoated polyethylene. These results point out that to coat UHMWPE with DLCH films could be a potential method to reduce backside wear in total hip and knee arthroplasties.Ministerio de Ciencia y Educación MAT2006-12603- C02-01, CSD2008-0002

Determination of Valanis model parameters in a bolted lap joint: Experimental and numerical analyses of frictional dissipation

In this work, Valanis model parameters, and their variation with bolt preload, were determined for a bolted lap joint, which consisted in two steel plates held together by a metric 12 screw. For this purpose, a series of transitory non-linear analyses were performed on the basis of a three dimensional finite element model of the bolted lap joint subjected to varying bolt preloads and tangential displacements. Curve fitting of hysteresis cycles obtained from numerical simulations allowed determination of Valanis model parameters as well as assessment of bolt preload influence on these parameters. In addition, the present numerical simulations provided information about the evolution of the contact state from stick to slip regimes between the bolted plates, reflecting the non-linear behaviour of the joint. Quasi-static tests at several preloads and tangential displacements conditions were conducted to validate Valanis model parameters previously obtained from numerical simulations. The present findings provided detailed information about the evolution of the aforementioned Valanis parameters with bolt preload. Thus, we confirmed that equivalent stiffness values corresponding to the macro-slip regime as well as the upper limit of the sticking regime (Et and σ0, respectively) are highly influenced by bolt preload levels. These results may prove useful to appropriately design bolted joints to be used under specific stiffness and damping criteria, and therefore reducing the vibration response of the joint.This work has been funded with project MYCT/FEDER Ref. BIA2006-15266-C02-02, and by Diputación General de Aragón (Grant no. G.C.I.A. 2011.T67).Peer Reviewe

The Brightest Cluster Galaxy in Abell 85: The Largest Core Known so far

We have found that the brightest cluster galaxy (BCG) in Abell~85, Holm 15A, displays the largest core so far known. Its cusp radius, $r_{\gamma} = 4.57 \pm 0.06$ kpc ($4.26^{\prime\prime}\pm 0.06^{\prime\prime}$), is more than 18 times larger than the mean for BCGs, and $\geq1$ kpc larger than A2261-BCG, hitherto the largest-cored BCG (Postman, Lauer, Donahue, et al. 2012) Holm 15A hosts the luminous amorphous radio source 0039-095B and has the optical signature of a LINER. Scaling laws indicate that this core could host a supermassive black hole (SMBH) of mass $M_{\bullet}\thicksim (10^{9}-10^{11})\,M_{\odot}$. We suggest that cores this large represent a relatively short phase in the evolution of BCGs, whereas the masses of their associated SBMH might be set by initial conditions.Comment: 14 pages, 3 figure, 2 tables, accepted for publication in ApJ Letters on October 6th, 2014, replacement of previous manuscript submitted on May 30th, 2014 to astro-p

Trajes, armas, escudos y banderas de todas las naciones de Europa o Etnología europea

Tít. de antep.: "Etnología europea"Es el Tomo primero, único publicad

Inflammatory Mediators in Vascular Disease: Identifying Promising Targets for Intracranial Aneurysm Research

Inflammatory processes are implicated in many diseases of the vasculature and have been shown to play a key role in the formation of intracranial aneurysms (IAs). Although the specific mechanisms underlying these processes have been thoroughly investigated in related pathologies, such as atherosclerosis, there remains a paucity of information regarding the immunopathology of IA. Cells such as macrophages and lymphocytes and their effector molecules have been suggested to be players in IA, but their specific interactions and the role of other components of the inflammatory response have yet to be determined. Drawing parallels between the pathogenesis of IA and other vascular disorders could provide a roadmap for developing a mechanistic understanding of the immunopathology of IA and uncovering useful targets for therapeutic intervention. Future research should address the presence and function of leukocyte subsets, mechanisms of leukocyte recruitment and activation, and the role of damage-associated molecular patterns in IA

Metallic and molecular orbital concepts in XMg8 clusters, X = Be-F

The electronic structure and stability of the XMg8 clusters (X = Be, B, C, N, O, and F) are studied using first principles theoretical calculations to understand the variation in bonding in heteroatomic clusters which mix simple divalent metals with main group dopants. We examine these progressions with two competing models, the first is a distorted nearly free electron gas model and the second is a molecular orbital picture examining the orbital overlap between the dopant and the cluster. OMg8 is found to be the most energetically stable cluster due to strong bonding of O with the Mg8 cluster. BeMg8 has the largest HOMO-LUMO gap due to strong hybridization between the Mg8 and the Be dopant states that form a delocalized pool of 18 valence electrons with a closed electronic shell due to crystal field effects. Be, B, and C are best described by the nearly free electron gas model, while N, O, and F are best described through molecular orbital concepts

Estudio de laboratorio sobre utilización de zeolita natural versus zeolita sintética en la fabricación de mezclas semicalientes

Zeolite can be used as an ingredient in warm bituminous mixes to reduce manufacturing temperatures. The zeolite for this purpose is usually synthetic, but natural zeolite can also be used. The research presented in this paper analyzed the use of natural zeolite from Cuba in the form of sand and filler as an additive in warm asphalt mixes and compared it to asphalt mixes with synthetic zeolite. The mixes were given the Marshall tests, and their moisture sensitivity and stiffness modulus values were also obtained. The results showed that both types of mix had a similar performance, which was only slightly lower than that of the reference mix. The use of different dosages of natural zeolite in the mixes gave the best results when the zeolite was incorporated as filler. This study demonstrated that the use of natural zeolite is an effective way of reducing the temperature of bituminous mixes.Las mezclas semicalientes permiten una reducción de la temperatura de fabricación respecto a las mezclas tradicionales, mediante la modificación del proceso de producción en planta o el empleo de aditivos. En esta investigación se analiza el empleo de zeolita natural procedente de Cuba como aditivo para la fabricación de mezclas semicalientes, en comparación con el empleo de zeolitas artificiales. Para ello, a través de pruebas de estabilidad Marshall, sensibilidad al agua y módulos de rigidez se realiza un estudio comparativo. El resultado obtenido mostró un comportamiento similar entre las mezclas con zeolita natural y la sintética, resultando en ambos casos ligeramente inferior al obtenido por la mezcla patrón. Además, se evaluó la influencia de la adición de zeolita natural a la mezcla en diferentes porcentajes, como filler o como arena, obteniendo mejores resultados con la incorporación en la fracción filler

Clústeres cinematográficos: ¿una estrategia para el desarrollo urbano y regional?

The film industry seems to have developed most strongly in specific cities/regions around the world. Based mainly on a review of the literature on urban and regional development in places where the film industry has usually been highly concentrated, this article:1) explains why this concentration has occurred, 2) describes common trends in the industry’s international development, 3) examines the film industry’s overall economic impact and its contribution to cities/regions, 4) reveals the shared characteristics of film cluster production systems around the world, 5) and presents a model for governments interested in economically enhancing their cities/regions through the formation and development of a film industry-based cluster as a strategy for regional development.La industria del cine parece haberse desarrollado más robustamente en ciertas ciudades/regiones alrededor del mundo. A partir de un repaso de la bibliografía sobre el desarrollo urbano y regional en lugares donde la industria cinematográfica suele tener altos niveles de concentración, este artículo: 1) explica por qué ocurre este proceso de concentración, 2) describe tendencias comunes en el desarrollo internacional de la industria, 3) examina el impacto económico general de la industria del cine y su contribución a distintas ciudades/regiones, 4) expone las características que comparten los sistemas de producción de clústeres cinematográficos alrededor del mundo y 5) presenta un modelo dirigido a gobiernos interesados en mejorar económicamente su ciudad/región a través de la formación y del desarrollo de un clúster cinematográfico pensado como una estrategia para el desarrollo regional