11,911 research outputs found
Recommended from our members
Cardiac Memory-induced T-wave Inversions
Introduction: Cardiac memory refers to T-wave inversions that result when normal ventricular activation resumes following a period of abnormal ventricular activation.Case Report: We present a case of a 29-year-old man with a pacemaker who presented with new, deep symmetric T-wave inversions caused by cardiac memory.Discussion: Abnormal ventricular activation is most commonly induced by ventricular pacing but can also occur in the setting of transient left bundle branch blocks, ventricular tachycardia, and intermittent ventricular pre-excitation.Conclusion: Recognition of this phenomenon may help to reduce unnecessary admissions, cardiac testing, and cardiac catheterizations
A catalogue sample of low mass galaxies observed in X-rays with central candidate black holes
We present a sample of -ray selected candidate black holes in 51 low mass
galaxies with {and mass up to M} obtained by
cross-correlating the NASA-SLOAN Atlas with the 3XMM catalogue. {We have also
searched in the available catalogues for radio counterparts of the black hole
candidates and find that 19 of the previously selected sources have also a
radio counterpart.} Our results show that about of the galaxies of our
sample host { an -ray source} (associated to a radio counterpart) spatially
coincident with the galaxy center, in agreement with { other recent works}. For
these {\it nuclear} sources, the -ray/radio fundamental plane relation
allows one to estimate the mass of the (central) candidate black holes which
results to be in the range M (with median
value of M and eight candidates having mass
below M). This result, while suggesting that -ray
emitting black holes in low-mass galaxies may have had a key role in the
evolution of such systems, makes even more urgent to explain how such massive
objects formed in galaxies. {Of course, dedicated follow-up observations both
in the -ray and radio bands, as well as in the optical, are necessary in
order to confirm our resultsComment: 15 Pages, 2 Figures, 3 Table
IIR Adaptive Filters for Detection of Gravitational Waves from Coalescing Binaries
In this paper we propose a new strategy for gravitational waves detection
from coalescing binaries, using IIR Adaptive Line Enhancer (ALE) filters. This
strategy is a classical hierarchical strategy in which the ALE filters have the
role of triggers, used to select data chunks which may contain gravitational
events, to be further analyzed with more refined optimal techniques, like the
the classical Matched Filter Technique. After a direct comparison of the
performances of ALE filters with the Wiener-Komolgoroff optimum filters
(matched filters), necessary to discuss their performance and to evaluate the
statistical limitation in their use as triggers, we performed a series of
tests, demonstrating that these filters are quite promising both for the
relatively small computational power needed and for the robustness of the
algorithms used. The performed tests have shown a weak point of ALE filters,
that we fixed by introducing a further strategy, based on a dynamic bank of ALE
filters, running simultaneously, but started after fixed delay times. The
results of this global trigger strategy seems to be very promising, and can be
already used in the present interferometers, since it has the great advantage
of requiring a quite small computational power and can easily run in real-time,
in parallel with other data analysis algorithms.Comment: Accepted at SPIE: "Astronomical Telescopes and Instrumentation". 9
pages, 3 figure
Estenosis esofágica benigna en un felino asociada a la administración oral de doxiciclina. Terapéutica endoscópica
Se presenta un caso de estenosis esofágica en un felino, asociada a la administración oral de doxiciclina. Se describe su tratamiento endoscópico.
Efficient photosynthesis of carbon monoxide from CO2 using perovskite photovoltaics
Artificial photosynthesis, mimicking nature in its efforts to store solar energy, has received considerable attention from the research community. Most of these attempts target the production of H2 as a fuel and our group recently demonstrated solar-to-hydrogen conversion at 12.3% efficiency. Here, in an effort to take this approach closer to real photosynthesis, which is based on the conversion of CO2, we demonstrate the efficient reduction of CO2 to carbon monoxide driven solely by simulated sunlight using water as the electron source. Employing series-connected perovskite photovoltaics and high-performance catalyst electrodes, we reach a solar-to-CO efficiency exceeding 6.5%, which represents a new benchmark in sunlight-driven CO2 conversion. Considering hydrogen as a secondary product, an efficiency exceeding 7% is observed. Furthermore, this study represents one of the first demonstrations of extended, stable operation of perovskite photovoltaics, whose large open-circuit voltage is shown to be particularly suited for this process
Ku & C Band solid state switch matrix for satellite payloads using LTCC multilayer substrate
This paper describes the design and development of Ku and C band solid state switch matrix for multimedia satellite payloads. The design, through the use of advanced packaging techniques, allows significant savings on mass and volume with respect to traditional electromechanical switches while guaranteeing a comparable reliability
Metric Versus Topological Receptive Entropy of Semigroup Actions
We study the receptive metric entropy for semigroup actions on probability spaces, inspired by a similar notion of topological entropy introduced by Hofmann and Stoyanov (Adv Math 115:54\u201398, 1995). We analyze its basic properties and its relation with the classical metric entropy. In the case of semigroup actions on compact metric spaces we compare the receptive metric entropy with the receptive topological entropy looking for a Variational Principle. With this aim we propose several characterizations of the receptive topological entropy. Finally we introduce a receptive local metric entropy inspired by a notion by Bowen generalized in the classical setting of amenable group actions by Zheng and Chen, and we prove partial versions of the Brin\u2013Katok Formula and the local Variational Principle
- …