123 research outputs found

    Tomographic findings and mortality in patients with severe and critical pneumonia with COVID-19 diagnosis

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    Introduction: A high percentage of patients with non-severe (17.9%) and severe (2.9%) atypical pneumonia do not display pulmonary tomographic findings upon hospital admission; furthermore, lesion associated with COVI-19 are peripherally distributed in a multifocal ground-glass pattern, as well as displaying an irregular consolidation pattern, with a posterior or lower lobe predilection. The main objective of this study was to identify the pulmonary radiological patterns in patients diagnosed with SARS-CoV-2 pneumonia, the factors associated with the need for mechanical ventilation, as well as their survival rates at 30 days. Methods: We report the pulmonary tomographic findings of 490 consecutive patients with severe and critical pneumonia due to SARS-CoV-2. The patients were classified according to the tomography and demographic findings, sepsis severity prognostic scales, Charlson comorbidity index (CCI), the Sequential Organ Failure Assessment (SOFA), and the Acute Physiology and Chronic Health Evaluation (APACHE IV). The Kaplan-Meier method was used to calculate survival distributions. Results: 89.80% of patients had ground-glass opacities, 81.63% radiologic consolidation sign, 42.45% vascular thickening pattern, 37.55% lymphadenopathies, 14.90% pleural effusion, and 2.65% pulmonary thrombosis; meanwhile, 91.02% had bilateral lesions, 85.51% had peripheral lesions, and 75.92% had basal lobe lesions. APACHE IV (HR, 1.191, 95% CI [1.126, 1.260]), SOFA (HR, 5.178, 95%CI [3.103, 8.641]), and CCI (HR, 0.673, 95%CI [0.510, 0.889]), as well as the pulmonary damage severity index (HR, 1.282, 95%CI [1.151, 1.428]), predict the need for invasive mechanical ventilation. Only moderate ARDS patients with mild and severe lung disease showed different 30-day mortality distributions (χ2 = 7.00, p = 0.008). Discussion: Although the survival distributions did not vary significantly, an overwhelming majority of patients (i.e., 84.35%) with a higher pulmonary damage severity index (i.e., 23>) died within 30 days of hospital admission, while only 25.91% with moderate lung damage and 2.42% with mild lung damage

    Persistent and occasional: searching for the variable population of the ZTF/4MOST sky using ZTF data release 11

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    We present a variability, color and morphology based classifier, designed to identify transients, persistently variable, and non-variable sources, from the Zwicky Transient Facility (ZTF) Data Release 11 (DR11) light curves of extended and point sources. The main motivation to develop this model was to identify active galactic nuclei (AGN) at different redshift ranges to be observed by the 4MOST ChANGES project. Still, it serves as a more general time-domain astronomy study. The model uses nine colors computed from CatWISE and PS1, a morphology score from PS1, and 61 single-band variability features computed from the ZTF DR11 g and r light curves. We trained two versions of the model, one for each ZTF band. We used a hierarchical local classifier per parent node approach, where each node was composed of a balanced random forest model. We adopted a 17-class taxonomy, including non-variable stars and galaxies, three transient classes, five classes of stochastic variables, and seven classes of periodic variables. The macro averaged precision, recall and F1-score are 0.61, 0.75, and 0.62 for the g-band model, and 0.60, 0.74, and 0.61, for the r-band model. When grouping the four AGN classes into one single class, its precision, recall, and F1-score are 1.00, 0.95, and 0.97, respectively, for both the g and r bands. We applied the model to all the sources in the ZTF/4MOST overlapping sky, avoiding ZTF fields covering the Galactic bulge, including 86,576,577 light curves in the g-band and 140,409,824 in the r-band. Only 0.73\% of the g-band light curves and 2.62\% of the r-band light curves were classified as stochastic, periodic, or transient with high probability (Pinit0.9P_{init}\geq0.9). We found that, in general, more reliable results are obtained when using the g-band model. Using the latter, we identified 384,242 AGN candidates, 287,156 of which have Pinit0.9P_{init}\geq0.9.Comment: Accepted for publication in Astronomy & Astrophysics. Abstract shortened for arXiv. Tables containing the classifications and features for the ZTF g and r bands, and the labeled sets will be available at CDS. Individual catalogs per class and band, as well as the labeled set catalogs, can be downloaded at Zenodo DOI:10.5281/zenodo.782604

    Multiwavelength monitoring of the nucleus in PBC J2333.9-2343: the giant radio galaxy with a blazar-like core

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    PBC J2333.9-2343 is a giant radio galaxy at z = 0.047 with a bright central core associated to a blazar nucleus. If the nuclear blazar jet is a new phase of the jet activity, then the small orientation angle suggest a dramatic change of the jet direction. We present observations obtained between September 2018 and January 2019 (cadence larger than three days) with Effeslberg, SMARTS-1.3m, ZTF, ATLAS, Swift, and Fermi-LAT, and between April-July 2019 (daily cadence) with SMARTS-1.3m and ATLAS. Large (>2x) flux increases are observed on timescales shorter than a month, which are interpreted as flaring events. The cross correlation between the SMARTS-1.3m monitoring in the NIR and optical shows that these data do not show significant time lag within the measured errors. A comparison of the optical variability properties between non-blazars and blazars AGN shows that PBC J2333.9-2343 has properties more comparable to the latter. The SED of the nucleus shows two peaks, that were fitted with a one zone leptonic model. Our data and modelling shows that the high energy peak is dominated by External Compton from the dusty torus with mild contribution from Inverse Compton from the jet. The derived jet angle of 3 degrees is also typical of a blazar. Therefore, we confirm the presence of a blazar-like core in the center of this giant radio galaxy, likely a Flat Spectrum Radio Quasar with peculiar properties.Comment: Accepted for publication in MNRAS. 15 pages, 6 figures, 2 appendix including tables and figure

    Brote de Alta Mortalidad en Terneros Lecheros por Diarrea Neonatal Producida por Cryptosporidium sp Asociado a Bacteriemia en un Establo Lechero de Lima

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    This paper presents and discusses the clinical and pathological findings of an outbreak of neonatal diarrhea that caused a high mortality in a dairy farm in Lima, Peru. The diarrheas did not respond to antibiotics and occurred in calves less than one month old. The animals showed signs of dehydration, fluid feces, fever and marked depression of sensory. They were negative for coronavirus and rotavirus but were positive for Criptosporidium sp. In the post mortem study, a severe diffuse acute mucohemorrhagic enterocolitis was found and the histopathological diagnosis corroborated that it was a severe acute diffuse catarrhal enteritis associated with Cryptosporidium sp and bacterial nests. In the barn was found deficiencies in the management of colostrum and hygiene of the containers in which the milk was offered to the calves. The problem was solved introducing a series of good practices in calf handling.En el presente trabajo se presenta y discute los hallazgos clínicos y patológicos de un brote de diarrea neonatal que causó una alta mortalidad en un establo lechero de Lima, Perú. Los cuadros de diarrea no respondían a la antibioterapia y se presentaron en terneros menores de un mes de edad. Los animales presentaban signos de deshidratación, heces líquidas, fiebre y marcada depresión de sensorio. Fueron negativos a coronavirus y rotavirus, pero fueron positivos a Criptosporidium sp. Al estudio posmortem se encontró una severa enterocolitis mucohemorrágica difusa aguda y al diagnóstico histopatológico se corroboró que se trataba de una severa enteritis catarral difusa aguda asociada a Cryptosporidium sp y nidos bacterianos. En el establo se encontró deficiencias en el manejo del calostro e higiene de los recipientes en los que se ofrecía la leche a los terneros. El problema fue solucionado introduciendo una serie de buenas prácticas de manejo del terneraje

    Ordered magnetism in the intrinsically decorated jeff = 1 2 α-CoV3O8

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    The antiferromagnetic mixed valence ternary oxide α\alpha-CoV3_{3}O8_{8} displays disorder on the Co2+^{2+} site that is inherent to the IbamIbam space group. The zero field structural and dynamic properties of α\alpha-CoV3_{3}O8_{8}~have been investigated using a combination of neutron and x-ray diffraction, DC susceptibility, and neutron spectroscopy. The low temperature magnetic and structural properties are consistent with a random macroscopic distribution of Co2+^{2+} over the 16kk metal sites. However, by applying the sum rules of neutron scattering we observe the collective magnetic excitations are parameterized with an ordered Co2+^{2+} arrangement and critical scattering consistent with a three dimensional Ising universality class. The low energy spectrum is well-described by Co2+^{2+} cations coupled viavia a three dimensional network composed of competing ferromagnetic and stronger antiferromagnetic superexchange within the abab plane and along cc, respectively. While the extrapolated Weiss temperature is near zero, the 3D dimensionality results in long range antiferromagnetic order at TNT\rm{_{N}}\sim 19 K. A crystal field analysis finds two bands of excitations separated in energy at ω\hbar \omega \sim 5 meV and 25 meV, consistent with a jeff=12j\rm{_{eff}}=\frac{1}{2} ground state with little mixing between spin-orbit split Kramers doublets. A comparison of our results to the random 3D Ising magnets and other compounds where spin-orbit coupling is present indicate that the presence of an orbital degree of freedom, in combination with strong crystal field effects and well-separated jeffj\rm{_{eff}} manifolds may play a key role in making the dynamics largely insensitive to disorder.Comment: 25 pages, 8 figures, 1 figure in Appendi

    The extreme HBL behaviour of Markarian 501 during 2012

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    A multiwavelength campaign was organized to take place between March and July of 2012. Excellent temporal coverage was obtained with more than 25 instruments, including the MAGIC, FACT and VERITAS Cherenkov telescopes, the instruments on board the Swift and Fermi spacecraft, and the telescopes operated by the GASP-WEBT collaboration. Mrk 501 showed a very high energy (VHE) gamma-ray flux above 0.2 TeV of \sim0.5 times the Crab Nebula flux (CU) for most of the campaign. The highest activity occurred on 2012 June 9, when the VHE flux was \sim3 CU, and the peak of the high-energy spectral component was found to be at \sim2 TeV. This study reports very hard X-ray spectra, and the hardest VHE spectra measured to date for Mrk 501. The fractional variability was found to increase with energy, with the highest variability occurring at VHE, and a significant correlation between the X-ray and VHE bands. The unprecedentedly hard X-ray and VHE spectra measured imply that their low- and high-energy components peaked above 5 keV and 0.5 TeV, respectively, during a large fraction of the observing campaign, and hence that Mrk 501 behaved like an extreme high-frequency- peaked blazar (EHBL) throughout the 2012 observing season. This suggests that being an EHBL may not be a permanent characteristic of a blazar, but rather a state which may change over time. The one-zone synchrotron self-Compton (SSC) scenario can successfully describe the segments of the SED where most energy is emitted, with a significant correlation between the electron energy density and the VHE gamma-ray activity, suggesting that most of the variability may be explained by the injection of high-energy electrons. The one-zone SSC scenario used reproduces the behaviour seen between the measured X-ray and VHE gamma-ray fluxes, and predicts that the correlation becomes stronger with increasing energy of the X-rays

    Forest Biodiversity Assessment in Peruvian Andean Montane Cloud Forest

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    Cloud forests are unusual and fragile habitats, being one of the least studied and least understood ecosystems. The tropical Andean dominion is considered one of the most significant places in the world as rega rds biological diversity, with a very high level of endemism. The biodiversity was analysed in an isolated remnant area of a tropical montane cloud forest known as the ?Bosque de Neblina de Cuyas?, in the North of the Peruvian Andean range. Composition, structure and dead wood were measured or estimated. The values obtained were compared with other cloud forests. The study revealed a high level of forest biodiversity, although the level of biodiversity differs from one area to another: in the inner areas, where human pressure is almost inexistent, the biodiversity values increase. The high species richness and the low dominance among species bear testimony to this montane cloud forest as a real enclave of biodiversity
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