1,070 research outputs found
Nanotechnologies and health: juridical and philosophical implications
Although their applications have not yet extended widely due to their incipient state, nano-technologies and nano-medicines may be presumed to be at the origin of the next great technological revolution, foreseeably contributing to a new stage with respect to evolutions in mankind’s progress. Their possibilities are truly immense in enormously varied spheres, but the risks and uncertainties they engender are enormous too. Because access and use of the unceasingly increasing mega-quantity of information they generate will place further strain on the protection of personal life, privacy, the exercise of freedom, as well as the safeguarding of other fundamental principles and rights
An Approach to Publish Spatial Data on the Web: The GeoLinked Data Case
In this paper we report on an ongoing process aimed at publishing hydrographical data on the Web with a Spanish GeoLinked Data Use Case. Moreover, we discuss the process we followed, and propose methodological guidelines for all the activities involved within the process
Detection of the onset of nanocrystallization by calorimetric and magnetic measurements
It is generally accepted that measurements of the magnetic properties are more sensitive than measurements of the enthalpy changes in the detection of the onset of crystallization of ferromagnetic phases emerging from a paramagnetic amorphous alloy. In this work, it is shown that the formation of a very fine nanocrystalline microstructure can make this assumption incorrect. Under some circumstances, the nanocrystallization onset temperature obtained from magnetic techniques is higher than the one obtained from enthalpy changes. The phenomenon is explained in terms of the superparamagnetic behavior of the uncoupled nanocrystals at the very early stages of nanocrystallizatio
Antibiotic resistance in hospital infections: the role of newer cephalosporins
Pla general de les obres de l'AVE a l'estació
la Sagrera
Evidence for intermediate-age stellar populations in early-type galaxies from K-band spectroscopy
The study of stellar populations in early-type galaxies in different
environments is a powerful tool for constraining their star formation
histories. This study has been traditionally restricted to the optical range,
where dwarfs around the turn-off and stars at the base of the RGB dominate the
integrated light at all ages. The near-infrared spectral range is especially
interesting since in the presence of an intermediate-age population, AGB stars
are the main contributors. In this letter, we measure the near-infrared indices
NaI and D for a sample of 12 early-type galaxies in low density
environments and compare them with the Fornax galaxy sample presented by Silva
et al. (2008). The analysis of these indices in combination with Lick/IDS
indices in the optical range reveals i) the NaI index is a metallicity
indicator as good as C4668 in the optical range, and ii) D is a
tracer of intermediate-age stellar populations. We find that low-mass galaxies
in low density environments show higher NaI and D than those located
in Fornax cluster, which points towards a late stage of star formation for the
galaxies in less dense environments, in agreement with results from other
studies using independent methods.Comment: 7 pages, 3 figures, accepted for publication in ApJ
Influence of Milling Time on the Homogeneity and Magnetism of a Fe70Zr30 Partially Amorphous Alloy: Distribution of Curie Temperatures
In this work, the mechanically alloyed Fe70Zr30 (at. %) composition has been used to study the influence of milling time on its homogeneity and magnetic properties. The microstructure and Fe environment results show the formation of an almost fully amorphous alloy after 50 h of milling in a mixture of pure 70 at. % Fe and 30 at. % Zr. The soft magnetic behavior of the samples enhances with the increase of the milling time, which is ascribed to the averaging out of the magnetocrystalline anisotropy as the crystal size decreases and the amorphous fraction increases. The formation of a non-perfectly homogenous system leads to a certain compositional heterogeneity, motivating the existence of a distribution of Curie temperatures. The parameters of the distribution (the average Curie temperature, T C ¯ , and the broadening of the distribution, ∆ T C ) have been obtained using a recently reported procedure, based on the analysis of the approach towards the saturation curves and the magnetocaloric effect. The decrease of ∆ T C and the increase of T C ¯ with the milling time are in agreement with the microstructural results. As the remaining α-Fe phase decreases, the amorphous matrix is enriched in Fe atoms, enhancing its magnetic response.AEI/FEDER-UE Project MAT 2016-77265-
On the Environmental Dependence of Cluster Galaxy Assembly Timescale
We present estimates of CN and Mg overabundances with respect to Fe for
early-type galaxies in 8 clusters over a range of richness and morphology.
Spectra were taken from the Sloan Digital Sky Survey (SDSS) DR1, and from WHT
and CAHA observations. Abundances were derived from absorption lines and single
burst population models, by comparing galaxy spectra with appropriately
broadened synthetic model spectra. We detect correlations between [Mg/CN] and
[CN/Fe] and cluster X-ray luminosity. No correlation is observed for [Mg/Fe].
We also see a clear trend with the richness and morphology of the clusters.
This is interpreted given varying formation timescales for CN, Mg and Fe, and a
varying star formation history in early-type galaxies as a function of their
environment: intermediate-mass early-type galaxies in more massive clusters are
assembled on shorter timescales than in less massive clusters, with an upper
limit of ~1 Gyr.Comment: Accepted for publication in ApJ Letter
Derivatización de nanoclústeres de oro protegidos por tioprina
II Encuentro sobre nanociencia y nanotecnología de investigadores y tecnólogos de la Universidad de Córdoba. NANOUC
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