High resolution spectroscopy of the BCD galaxy Haro 15: II. Chemodynamics

We present a detailed study of the physical properties of the nebular material in four star-forming knots of the blue compact dwarf galaxy Haro 15. Using long-slit and echelle spectroscopy obtained at Las Campanas Observatory, we study the physical conditions (electron density and temperatures), ionic and total chemical abundances of several atoms, reddening and ionization structure, for the global flux and for the different kinematical components. The latter was derived by comparing the oxygen and sulphur ionic ratios to their corresponding observed emission line ratios (the $\eta$ and $\eta$' plots) in different regions of the galaxy. Applying the direct method or empirical relationships for abundance determination, we perform a comparative analysis between these regions. The similarities found in the ionization structure of the different kinematical components implies that the effective temperatures of the ionizing radiation fields are very similar in spite of some small differences in the ionization state of the different elements. Therefore the different gaseous kinematical components identified in each star forming knot are probably ionized by the same star cluster. However, the difference in the ionizing structure of the two knots with knot A showing a lower effective temperature than knot B, suggests a different evolutionary stage for them consistent with the presence of an older and more evolved stellar population in the first.Comment: 21 pages, 6 figures, 8 tables, accepted by MNRA

The Role of Large and Small Scale Hydropower for Energy and Water Security in the Spanish Duero Basin

Hydropower has been increasingly seen as a two-fold solution to the provision of renewable energy and water storage. However, the massive deployment of both large and small scale hydropower projects has been reported to cause important environmental impacts at the basin scale. This study assesses the differential contributions to regional energy and water security of large (LHP) and small (SHP) scale hydropower deployment in the Spanish Duero basin, as well as associated cumulative environmental impacts. This is performed through a selection of indicators measured in absolute and relative terms. The results suggest that LHP deployment contributes more to energy and water security, performing better in 10 of the 12 indicators. It also shows higher absolute environmental impacts on flow regime and habitat loss. Meanwhile, when analyzed in relative terms, SHP shows greater impacts in all categories as a result of cumulative effects cascading along the rivers system. These findings suggest that optimizing the use of existing hydropower infrastructure would be beneficial for energy, water and environmental security. This could be implemented by substantially reducing the number of low capacity plants with almost no impact on final energy generation, while enhancing the pumping and storage potential of higher capacity plants

Opciones terapéuticas en quistes odontogénicos. Revisión

Los huesos maxilares constituyen asiento de una gran variedad de quistes y neoplasias que pueden ser de difícil diagnóstico. De entre todos los procesos tumorales que se dan en el territorio maxilofacial, los quistes son de gran importancia debido a la frecuencia de su presentación. Los quistes maxilares tienen distinto origen y comportamiento clínico. A partir de la clasificación de la OMS de 1992, esta revisión estudia las características clínicas, radiográficas y epidemiológicas de los quistes del desarrollo odontógenos. Una adecuada exploración clínica y radiográfica por parte del odontólogo es suficiente para alcanzar un diagnóstico de presunción. Las consideraciones clínicas y terapéuticas de cada uno de estos quistes son variables, por lo que es necesario conocer el comportamiento epidemiológico de ellos. El diagnóstico de presunción, el tamaño de la lesión y la relación de esta con estructuras anatómicas vecinas condicionará el tipo de tratamiento. El diagnóstico definitivo lo dictaminará el análisis anatomopatológico

Vortex-lattice dynamics with channeled pinning potential landscapes

We have studied vortex-lattice dynamics as a function of driving force direction, in superconducting Nb films with periodic pinning arrays of magnetic dots. Square and rectangular symmetry arrays define channels that guide the vortex-lattice motion. We investigated the effect of the driving force direction on the commensurability between the vortex-lattice and dots array. We also studied the transverse depinning of the vortex-lattice as is moving longitudinally along channels. We found that transverse depinning forces are enhanced with respect to the static situation. The results are discussed in terms of the dynamical evolution of order in the vortex-lattice

Integral field spectroscopy of nitrogen overabundant blue compact dwarf galaxies

We study the spatial distribution of the physical properties and of oxygen and nitrogen abundances in three Blue Compact Dwarf Galaxiess (HS 0128+2832, HS 0837+4717 and Mrk 930) with a reported excess of N/O in order to investigate the nature of this excess and, particularly, if it is associated with Wolf-Rayet (WR) stars We have observed these BCDs by using PMAS integral field spectroscopy in the optical spectral range (3700 - 6900 {\AA}), mapping their physical-chemical properties, using both the direct method and appropriate strong-line methods. We make a statistical analysis of the resulting distributions and we compare them with the integrated properties of the galaxies. Our results indicate that outer parts of the three galaxies are placed on the "AGN-zone" of the [NII]/H{\alpha} vs. [OIII]/H{\beta} diagnostic diagram most likely due to a high N/O combined with the excitation structure in these regions. From the statistical analysis, it is assumed that a certain property can be considered as spatially homogeneous (or uniform) if a normal gaussian function fits its distribution in several regions of the galaxy. Moreover, a disagreement between the integrated properties and the mean values of the distribution usually appears when a gaussian does not fit the corresponding distribution. We find that for Mrk 930, the uniformity is found for all parameters, except for electron density and reddening. The rotation curve together with the H{\alpha} map and UV images, reveal a perturbed morphology and possible interacting processes. The N/O is found to be constant in the three studied objects at spatial scales of the order of several kpc so we conclude that the number of WR stars estimated from spectroscopy is not sufficient to pollute the ISM and to produce the observed N/O excess in these objectsComment: 17 pages, 14 figures, accepted for publication in Astronomy & Astrophysic

Influence of Connection Type and Platform Diameter on Titanium Dental Implants Fatigue: Non-Axial Loading Cyclic Test Analysis

Two-pieces dental implants must provide stability of the implant-abutment-interface. The connection type and platform diameter could influence the biomechanical resistance and stress distribution. This study aims to evaluate the fatigue for different types of connections, external and internal, and different platform diameters. Three implant designs with the same length were used: (a) external hexagon/narrow platform; (b) internal double hexagon/narrow platform; (c) internal octagon/regular platform. A fatigue test was developed to establish the number of cycles needed before fracture. A 30º oblique load with a sinusoidal function of fatigue at a frequency of 15 Hz and 10% stress variation was applied to each system. The fatigue load limit (FLL) for design (a) was 190N, being the nominal-curvature-moment (NCM) = 1.045; FLL = 150 N, with a NCM = 0.825 for (b), and FLL = 325 N, with a NCM = 1.788 for (c). The platform diameter affects the FLL, obtaining lower FLL on a narrow platform. The connection type interferes with the implant walls' width, especially in narrow implants, making internal connections more unstable at this level. Long-term clinical studies to assess the restoration's success rate and survival are mandatory

Magnetic properties of Ni nanoparticles dispersed in silica prepared by high-energy ball milling

We analyze the magnetic properties of mechanically ground nanosized Ni particles dispersed in a SiO_2 matrix. Our magnetic characterization of the as-milled samples show the occurrence of two blocking processes and that of non-monotonic milling time evolutions of the magnetic-order temperature, the high-field magnetization and the saturation coercivity. The measured coercivities exhibit giant values and a uniaxial- type temperature dependence. Thermal treatment carried out in the as-prepared samples result in a remarkable coercivity reduction and in an increase of the high-field magnetization. We conclude, on the basis of the consideration of a core (pure Ni) and shell (Ni-Si inhomogeneous alloy) particle structure, that the magnetoelastic anisotropy plays the dominant role in determining the magnetic properties of our particles

Integral field spectroscopy of H II region complexes: the outer disc of NGC 6946

This is an electronic version of an article published in Monthly Notices of the Royal Astronomical Society. García-Benito, R., Díaz, A., Hägele, G.F., Pérez-Montero, E., López, J., Vílchez, J.M., Pérez, E., Terlevich, E., Terlevich, R., D. Rosa-González. Integral field spectroscopy of H II region complexes: the outer disc of NGC 6946. Monthly Notices of the Royal Astronomical Society 408 (2010): 2234-225