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 $X$-ray selected candidate black holes in 51 low mass galaxies with $z\le 0.055$ {and mass up to $10^{10}$ M$_{\odot}$} 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 $37\%$ of the galaxies of our sample host { an $X$-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 $X$-ray/radio fundamental plane relation allows one to estimate the mass of the (central) candidate black holes which results to be in the range $10^{4}-2\times10^{8}$ M$_{\odot}$ (with median value of $\simeq 3\times 10^7$ M$_{\odot}$ and eight candidates having mass below $10^{7}$ M$_{\odot}$). This result, while suggesting that $X$-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 $X$-ray and radio bands, as well as in the optical, are necessary in order to confirm our resultsComment: 15 Pages, 2 Figures, 3 Table

Astrometric microlensing

Astrometric microlensing will offer in the next future a new channel for investigating the nature of both lenses and sources involved in a gravitational microlensing event. The effect, corresponding to the shift of the position of the multiple image centroid with respect to the source star location, is expected to occurr on scales from micro-arcoseconds to milli-arcoseconds depending on the characteristics of the lens-source system. Here, we consider different classes of events (single/binary lens acting on a single/binary source) also accounting for additional effects including the finite source size, the blending and orbital motion. This is particularly important in the era of Gaia observations which is making possible astrometric measurements with unprecedent quality.Comment: On IJMP D, 15 pages, 6 Figure

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

A comparison of different indicators of chaos based on the deviation vectors. Application to symplectic mappings

The aim of this research work is to compare the reliability of several variational indicators of chaos on mappings. The Lyapunov Indicator (LI); the Mean Exponential Growth factor of Nearby Orbits (MEGNO); the Smaller Alignment Index (SALI); the Fast Lyapunov Indicator (FLI); the Dynamical Spectra of stretching numbers (SSN) and the corresponding Spectral Distance (D); and the Relative Lyapunov Indicator (RLI), which is based on the evolution of the difference between two close orbits, have been included. The experiments presented herein allow us to reliably suggest a group of chaos indicators to analyze a general mapping. We show that a package composed of the FLI and the RLI (to analyze the phase portrait globally) and the MEGNO and the SALI (to analyze orbits individually) is good enough to make a description of the systems' dynamics.Comment: 25 pages, 40 figures. Celestial Mechanics and Dynamical Astronomy, in pres

Temporal pattern of Klebsiella pneumoniae carbapenemase (KPC) on surface of an intensive care unit of a large hospital

Background: Carbapenem-resistant Enterobacteriaceae are an increasing cause of healthcare-associated infections worldwide. Patients with infections caused by Klebsiella pneumoniae resistant to carbapenems (KPC) have significant increases in both allcause mortality and 30-day mortality. The aims of this study was to investigate the prevalence of KPC on environmental samples collected during and after an outbreak caused by KPC in an intensive care unit (ICU) of a teaching hospital. Methods: Between 2010 and 2014 we conducted a total of 132 environmental monitoring campaigns from different critical surface of ICU ward in a Teaching Hospital Policlinico Umberto I. Samples were collected on surfaces in patient rooms and health care area. All samples were cultured and K. pneumoniae isolates were identified by standard microbiological techniques. The presumptive colonies were confirmed and tested for antibiotic resistance by an automated system. K. pneumoniae resitant to carbapenems were tested for carbapenemase production by modified Hodge test. Results: A total of 2526 environmental samples were collected from November 2010 to July 2014. Of those, 111 resulted positive for K. pneumoniae while KPC were 95 (85.6% of all K. pneumoniae, 3.8% of total samples). KPC was recovered in all patient rooms with similar proportion (5.1-5.6%) with the exception of patient 6 bed room where it was lower (2.4%). The pathogen was not recovered in rooms dedicated to healthcare personnel and doctors. Among surfaces, the highest proportion of KPC resulted on bedrail (6.8%), more than double than other surfaces. Washbasins had nearly half of samples KPC positive (1.2%). Conclusions: Despite previous studies suggested that environment plays a minor role in the transmission of carbapenem-resistant enterobacteriaceae, our data highlighted that surfaces represents a significant reservoir for KPC possibly supporting transiently contamination of hands of healthcare workers in our ICU. Our results confirm that KPC are more likely found on surfaces closer to the patient than on those situated further away

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