4,833 research outputs found
La lectura irreverente o la educación descuidada. Un episodio de historia cultural.
En este artÃculo se reflexiona, a partir del episodio protagonizado en 1843 por la Condesa de Mina durante un paseo en carruaje con Isabel II, sobre las distintas formas de entender la lectura en la España del siglo XIX y las tensiones entre una lectura individual y silenciosa y una lectura oral y compartida, como dos dimensiones de la transformación de las prácticas culturales y educativas de su tiempo
Automatic diagnosis of strict left bundle branch block using a wavelet-based approach
Patients with left bundle branch block (LBBB) are known to have a good clinical response to cardiac resynchronization therapy. However, the high number of false positive diagnosis obtained with the conventional LBBB criteria limits the effectiveness of this therapy, which has yielded to the definition of new stricter criteria. They require prolonged QRS duration, a QS or rS pattern in the QRS complexes at leads V1 and V2 and the presence of mid-QRS notch/slurs in 2 leads within V1, V2, V5, V6, I and aVL. The aim of this work was to develop and assess a fully-automatic algorithm for strict LBBB diagnosis based on the wavelet transform. Twelve-lead, high-resolution, 10-second ECGs from 602 patients enrolled in the MADIT-CRT trial were available. Data were labelled for strict LBBB by 2 independent experts and divided into training (n = 300) and validation sets (n = 302) for assessing algorithm performance. After QRS detection, a wavelet-based delineator was used to detect individual QRS waves (Q, R, S), QRS onsets and ends, and to identify the morphological QRS pattern on each standard lead. Then, multilead QRS boundaries were defined in order to compute the global QRS duration. Finally, an automatic algorithm for notch/slur detection within the QRS complex was applied based on the same wavelet approach used for delineation. In the validation set, LBBB was diagnosed with a sensitivity and specificity of Se = 92.9% and Sp = 65.1% (Acc = 79.5%, PPV = 74% and NPV = 89.6%). The results confirmed that diagnosis of strict LBBB can be done based on a fully automatic extraction of temporal and morphological QRS features. However, it became evident that consensus in the definition of QRS duration as well as notch and slurs definitions is necessary in order to guarantee accurate and repeatable diagnosis of complete LBBB
A work of by the Leprince at Royal Chapel of the Cathedral of Seville
En el Altar Mayor de la Real Capilla de Nuestra Señora de los Reyes de la Catedral de Sevilla se encuentra un juego de cruz y candeleros del que hasta hoy se ignoraba la autorÃa. Nuevos documentos han permitido atribuirlos a los broncistas franceses Leprince y conocer que las piezas fueron un regalo del rey Fernando VII para dicha Capilla.In the Main Altar of Our Lady of the Kings’ Royal Chapel in the Cathedral of Seville there is a set consisting of a cross and several candlesticks of unknown author until now. New documents allow us to claim that the authors were the french bronzemakers Leprince. These documents also show that the pieces were a present from the king Ferdinand VII to that Chapel
Entanglement of Dirac fields in an expanding spacetime
We study the entanglement generated between Dirac modes in a 2-dimensional
conformally flat Robertson-Walker universe. We find radical qualitative
differences between the bosonic and fermionic entanglement generated by the
expansion. The particular way in which fermionic fields get entangled encodes
more information about the underlying space-time than the bosonic case, thereby
allowing us to reconstruct the parameters of the history of the expansion. This
highlights the importance of bosonic/fermionic statistics to account for
relativistic effects on the entanglement of quantum fields.Comment: revtex4, 7 figures, I.F. previously published as Fuentes-Guridi and
Fuentes-Schuller. Journal reference update
Mechanical systems subjected to generalized nonholonomic constraints
We study mechanical systems subject to constraint functions that can be
dependent at some points and independent at the rest. Such systems are modelled
by means of generalized codistributions. We discuss how the constraint force
can transmit an impulse to the motion at the points of dependence and derive an
explicit formula to obtain the ``post-impact'' momentum in terms of the
``pre-impact'' momentum.Comment: 24 pages, no figure
Interactions, star formation and extended nebulae in SDSS type 2 quasars at 0.3<~ z <~ 0.6
We present long-slit spectroscopy and imaging data obtained with FORS2 on the
Very Large Telescope of 13 optically selected type 2 quasars at z~0.3-0.6 from
the original sample of Zakamska et al. (2003). The sample is likely to be
affected by different selection biases. We investigate the evidence for: a)
mergers/interactions b) star formation activity in the neighborhood of the
quasars and c) extended emission line regions and their nature. Evidence for
mergers/interactions is found in 5/13 objects. This is a lower limit for our
sample, given the shallowness of most of our continuum images. Although AGN
photoionization cannot be totally discarded, line ratios consistent with
stellar photoionization are found in general in companion galaxies/knots/nuclei
near these same objects. On the contrary, the gas in the neighborhood of the
quasar nucleus shows line ratios inconsistent with HII galaxies and typical of
AGN photoionized nebulae. A natural scenario to explain the observations is
that star formation is ongoing in companion galaxies/knots/nuclei, possibly
triggered by the interactions. These systems are, therefore, composite in their
emission line properties showing a combination of AGN and star formation
features.
Extended emission line regions (EELRs) have been found in 7/13 objects,
although this fraction might be higher if a complete spatial coverage around
the quasars was performed. The sizes vary between few and up to 64 kpc. In
general, the EELRs apparently consist of an extended nebula associated with the
quasar. In at least one case the EELR is associated with ionized tidal
features.Comment: Accepted for publication in MNRAS. 19 pages, 30 figure
Numerical explicit analysis of hole flanging by single-stage incremental forming
The use of Single-Point Incremental Forming (SPIF) technology in hole flanging operations using multi-stages strategies have been widely studied in the last few years. However, these strategies are very time-consuming, limiting its industrial application.In a very recent work of the authors, the capability of SPIF process to successfully perform hole-flanges using a single-stage strategy has been experimentally investigated. The aim of the present work is to develop a numerical model of this process to beable to predict the sheet failure as a function of the size of the pre-cut hole. The numerical results are compared and discussed in the light of experimental tests over AA7075-O metal sheets with 1.6mm thickness.Ministerio de EconomÃa y Competitividad DPI2015-64047-
Integral field spectroscopy of type-II QSOs at z=0.3-0.4
We present and analyse integral-field observations of six type-II QSOs with
z=0.3-0.4, selected from the Sloan Digital Sky Survey (SDSS). Two of our sample
are found to be surrounded by a nebula of warm ionized gas, with the largest
nebula extending across 8" (40 kpc). Some regions of the extended nebulae show
kinematics that are consistent with gravitational motion, while other regions
show relatively perturbed kinematics: velocity shifts and line widths too large
to be readily explained by gravitational motion. We propose that a ~20 kpc x20
kpc outflow is present in one of the galaxies. Possible mechanisms for
triggering the outflow are discussed. In this object, we also find evidence for
ionization both by shocks and the radiation field of the AGN.Comment: 6 pages, 5 figures, accepted by MNRAS Letter
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