Casuística y manejo en las infecciones intrahospitalarias

El uso indiscriminado de cefalosporinas de tercera generación y quinolonas incide directamente en la aparición de enterobacterias portadoras de betalactamasas de espectro extendido (BLEE). Las infecciones causadas por estas últimas deben ser tratadas casi exclusivamente, en la mayoría de los casos, por antibióticos carbapenemes. A partir del aumento de utilización de estos antimicrobianos, que se considera en el ámbito intrahospitalario como de uso restringido, aparecen los microorganismos con mayor resistencia aún. Este es el mejor ejemplo de cómo cuando se desafían a las bacterias con diferentes antibióticos, éstas tienen la capacidad de adquirir cada vez mas mecanismos de resistencia que se tornan redundantes y aditivos, dejando a los profesionales, sin alternativa terapéutica. Es indispensable reservar y preservar los antibióticos que aún tenemos disponibles, ya que tratar las infecciones por gérmenes multirresistentes es cada vez mas complicado.Facultad de Ciencias Veterinaria

Casuística y manejo en las infecciones intrahospitalarias

El uso indiscriminado de cefalosporinas de tercera generación y quinolonas incide directamente en la aparición de enterobacterias portadoras de betalactamasas de espectro extendido (BLEE). Las infecciones causadas por estas últimas deben ser tratadas casi exclusivamente, en la mayoría de los casos, por antibióticos carbapenemes. A partir del aumento de utilización de estos antimicrobianos, que se considera en el ámbito intrahospitalario como de uso restringido, aparecen los microorganismos con mayor resistencia aún. Este es el mejor ejemplo de cómo cuando se desafían a las bacterias con diferentes antibióticos, éstas tienen la capacidad de adquirir cada vez mas mecanismos de resistencia que se tornan redundantes y aditivos, dejando a los profesionales, sin alternativa terapéutica. Es indispensable reservar y preservar los antibióticos que aún tenemos disponibles, ya que tratar las infecciones por gérmenes multirresistentes es cada vez mas complicado.Facultad de Ciencias Veterinaria

Casuística y manejo en las infecciones intrahospitalarias

El uso indiscriminado de cefalosporinas de tercera generación y quinolonas incide directamente en la aparición de enterobacterias portadoras de betalactamasas de espectro extendido (BLEE). Las infecciones causadas por estas últimas deben ser tratadas casi exclusivamente, en la mayoría de los casos, por antibióticos carbapenemes. A partir del aumento de utilización de estos antimicrobianos, que se considera en el ámbito intrahospitalario como de uso restringido, aparecen los microorganismos con mayor resistencia aún. Este es el mejor ejemplo de cómo cuando se desafían a las bacterias con diferentes antibióticos, éstas tienen la capacidad de adquirir cada vez mas mecanismos de resistencia que se tornan redundantes y aditivos, dejando a los profesionales, sin alternativa terapéutica. Es indispensable reservar y preservar los antibióticos que aún tenemos disponibles, ya que tratar las infecciones por gérmenes multirresistentes es cada vez mas complicado.Facultad de Ciencias Veterinaria

Self-consistent method to extract non-linearities from pulsating stars light curves I. Combination frequencies

Combination frequencies are not solutions of the perturbed stellar structure equations. In dense power spectra from a light curve of a given multi-periodic pulsating star, they can compromise the mode identification in an asteroseismic analysis, hence they must be treated as spurious frequencies and conveniently removed. In this paper, a method based on fitting the set of frequencies that best describe a general non-linear model, like the Volterra series, is presented. The method allows to extract these frequencies from the power spectrum, so helping to improve the frequency analysis enabling hidden frequencies to emerge from the initially considered as noise. Moreover, the method yields frequencies with uncertainties several orders of magnitude smaller than the Rayleigh dispersion, usually taken as the present error in a standard frequency analysis. Furthermore, it is compatible with the classical counting cycles method, the so-called O-C method, which is valid only for mono-periodic stars. The method opens the possibility to characterise the non-linear behaviour of a given pulsating star by studying in detail the complex generalised transfer functions.Comment: 10 pages, 4 figures. Submitted to MNRA

Impact of gaps in the asteroseismic characterization of pulsating stars. I. On the efficiency of pre-whitening

It is known that the observed distribution of frequencies in CoRoT and Kepler {\delta} Scuti stars has no parallelism with any theoretical model. Pre-whitening is a widespread technique in the analysis of time series with gaps from pulsating stars located in the classical instability strip such as {\delta} Scuti stars. However, some studies have pointed out that this technique might introduce biases in the results of the frequency analysis. This work aims at studying the biases that can result from pre-whitening in asteroseismology. The results will depend on the intrinsic range and distribution of frequencies of the stars. The periodic nature of the gaps in CoRoT observations, just in the range of the pulsational frequency content of the {\delta} Scuti stars, is shown to be crucial to determine their oscillation frequencies, the first step to perform asteroseismolgy of these objects. Hence, here we focus on the impact of pre-whitening on the asteroseismic characterization of {\delta} Scuti stars. We select a sample of 15 {\delta} Scuti stars observed by the CoRoT satellite, for which ultra-high quality photometric data have been obtained by its seismic channel. In order to study the impact on the asteroseismic characterization of {\delta} Scuti stars we perform the pre-whitening procedure on three datasets: gapped data, linearly interpolated data, and ARMA interpolated data. The different results obtained show that at least in some cases pre-whitening is not an efficient procedure for the deconvolution of the spectral window. therefore, in order to reduce the effect of the spectral window to the minimum it is necessary to interpolate with an algorithm that is aimed to preserve the original frequency content, and not only to perform a pre-whitening of the data.Comment: 27 pages, 47 figures Tables and typos fixe

Primary pulmonary melanoma: the unexpected tumour

A 62-year-old woman was referred to our pulmonology team with exertional dyspnoea and chest tightness of 2 months duration. Her medical history included cervical cancer and thyroid nodules. Imaging studies showed collapse of left upper lobe. Fiberoptic bronchoscopy unveiled an endoluminal lesion and bronchial biopsy displayed features of melanoma. She denied a history of melanoma or excision of lesions of skin, mucous membranes or the eye. A thorough evaluation including combined positron emission tomography with CT scan excluded other possible sites of primary melanoma, but there was a metastasis in a thoracic vertebra. Palliative radiotherapy of the spine was performed. Chemotherapy initiation with dacarbazine was postponed by the appearance of a malignant pleural effusion, confirmed by pleural fluid cytology. After four cycles chemotherapy was discontinued due to disease progression. The patient is still alive with a follow-up of 12 months, currently on best supportive care

Properties of satellite galaxies in the SDSS photometric survey: luminosities, colours and projected number density profiles

We analyze photometric data in SDSS-DR7 to infer statistical properties of faint satellites associated to isolated bright galaxies (M_r<-20.5) in the redshift range 0.03<z<0.1. The mean projected radial profile shows an excess of companions in the photometric sample around the primaries, with approximately a power law shape that extends up to ~700kpc. Given this overdensity signal, a suitable background subtraction method is used to study the statistical properties of the population of bound satellites, down to magnitude M_r=-14.5, in the projected radial distance range 100 < r_p/kpc < 3 R_{vir}. We have also considered a color cut consistent with the observed colors of spectroscopic satellites in nearby galaxies so that distant redshifted galaxies do not dominate the statistics. We have tested the implementation of this procedure using a mock catalog. We find that the method is effective in reproducing the true projected radial satellite number density profile and luminosity distributions, providing confidence in the results derived from SDSS data. The spatial extent of satellites is larger for bright, red primaries. Also, we find a larger spatial distribution of blue satellites. For the different samples analyzed, we derive the average number of satellites and their luminosity distributions down to M_r=-14.5. The mean number of satellites depends very strongly on host luminosity. Bright primaries (M_r<-21.5) host on average ~6 satellites with M_r<-14.5, while primaries with -21.5<M_r<-20.5 have less than 1 satellite per host. We provide Schechter function fits to the luminosity distributions of satellite galaxies with faint-end slopes -1.3+/-0.2. This shows that satellites of bright primaries lack an excess population of faint objects, in agreement with the results in the Milky Way and nearby galaxies.Comment: 14 pages, 13 figures. Accepted for publication in Astronomical Journa