84 research outputs found

    Bright microwave pulses from PSR B0531+21 observed with a prototype transient survey receiver

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    Recent discoveries of transient radio events have renewed interest in time-variable astrophysical phenomena. Many radio transient events are rare, requiring long observing times for reliable statistical study. The National Aeronautics and Space Administration/Jet Propulsion Laboratory\u27s Deep Space Network (DSN) tracks spacecraft nearly continuously with 13 large-aperture, low system temperature radio antennas. During normal spacecraft operations, the DSN processes only a small fraction of the pre-detection bandwidth available from these antennas; any information in the remaining bandwidth, e.g., from an astronomical source in the same antenna beam as the spacecraft, is currently ignored. As a firmware modification to the standard DSN tracking receiver, we built a prototype receiver that could be used for astronomical transient surveys. Here, we demonstrate the receiver\u27s utility through observations of bright pulses from the Crab pulsar and describe attributes of potential transient survey observations piggybacking on operational DSN tracks. © 2014. The American Astronomical Society. All rights reserved.

    Trends and area variations in Potentially Preventable Admissions for COPD in Spain (2002-2013): A significant decline and convergence between areas

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    Background: Potentially Preventable Hospitalizations (PPH) are hospital admissions for conditions which are preventable with timely and appropriate outpatient care being Chronic Obstructive Pulmonary Disease (COPD) admissions one of the most relevant PPH. We estimate the population age-sex standardized relative risk of admission for COPD-PPH by year and area of residence in the Spanish National Health System (sNHS) during the period 2002–2013. Methods: The study was conducted in the 203 Hospital Service Areas of the sNHS, using the 2002 to 2013 hospital admissions for a COPD-PPH condition of patients aged 20 and over. We use conventional small area variation statistics and a Bayesian hierarchical approach to model the different risk structures of dependence in both space and time. Results: COPD-PPH admissions declined from 24.5 to 15.5 per 10, 000 persons-year (Men: from 40.6 to 25.1; Women: from 9.1 to 6.4). The relative risk declined from 1.19 (19 % above 2002–2013 average) in 2002 to 0.77 (30 % below average) in 2013. Both the starting point and the slope were different for the different regions. Variation among admission rates between extreme areas dropped from 6.7 times higher in 2002 to 4.6 times higher in 2013. Conclusions: COPD-PPH conditions in Spain have undergone a strong decline and a reduction in geographical variation in the last 12 years, suggesting a general improvement in health policies and health care over time. Variability among areas still remains, with a substantial room for improvement

    GW150914: First search for the electromagnetic counterpart of a gravitational-wave event by the TOROS collaboration

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    We present the results of the optical follow-up conducted by the TOROS collaboration of the first gravitational-wave event GW150914. We conducted unfiltered CCD observations (0.35-1 micron) with the 1.5-m telescope at Bosque Alegre starting ~2.5 days after the alarm. Given our limited field of view (~100 square arcmin), we targeted 14 nearby galaxies that were observable from the site and were located within the area of higher localization probability. We analyzed the observations using two independent implementations of difference-imaging algorithms, followed by a Random-Forest-based algorithm to discriminate between real and bogus transients. We did not find any bona fide transient event in the surveyed area down to a 5-sigma limiting magnitude of r=21.7 mag (AB). Our result is consistent with the LIGO detection of a binary black hole merger, for which no electromagnetic counterparts are expected, and with the expected rates of other astrophysical transients.Comment: ApJ Letters, in pres

    Molecular subtypes of breast cancer: prognostic implications and clinical and immunohistochemical characteristics

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    Fundamento. Los carcinomas de mama representan un grupo heterogéneo de tumores, tanto en su comportamiento clínico como pronóstico. El objetivo del presente trabajo es clasificar los carcinomas de mama en subtipos moleculares mediante marcadores inmunohistoquímicos y analizar las características clinicopatológicas e inmunohistoquímicas y los patrones de supervivencia y recaída de los distintos subtipos. Material y métodos. Se han clasificado 272 pacientes con diagnóstico de carcinoma de mama en cinco subtipos: carcinomas de mama de tipo basal, de tipo HER2, de tipo luminal A, de tipo luminal B y normal. Resultados. Los carcinomas de mama más frecuentes fueron los de tipo luminal A (62,5%), carcinomas de tipo luminal B (18%), carcinomas de tipo HER2 (9,9%), carcinomas de tipo basal (8,4%) y los de fenotipo normal (1,4%). Los carcinomas de mama de tipo luminal mostraron ser, con mayor frecuencia, de forma significativa, tumores bien diferenciados, de pequeño tamaño tumoral, con ganglios axilares negativos, estadio precoz en el momento del diagnóstico, niveles altos de BCL-2 y bajo índice de proliferación con Ki-67. En cambio, los carcinomas de mama de tipo basal y HER2 presentaban tumores de mayor tamaño, pobremente diferenciados, mayor compromiso ganglionar y estadios más avanzados en el momento del diagnóstico. Expresaban con mayor frecuencia índices de proliferación altos con Ki 67 y fueron los subtipos que en curvas de supervivencia global y de supervivencia libre de progresión mostraron un peor pronóstico. Conclusión. La clasificación del cáncer de mama basada en parámetros inmunohistoquímicos (IHQ) permite una mejor definición pronóstica. Tanto los carcinomas de mama de tipo basal como HER2 presentan características histopatológicas e IHQ más desfavorables así como peor supervivencia y menor tiempo de recaída mientras que los carcinomas de mama de tipo luminal manifiestan características más benignas y mejor pronóstico.Background. Breast carcinomas are a heterogeneous group of tumours, in both their clinical behavior and their prognosis. The aim of this article is to classify breast carcinomas according to molecular subtypes by means of immunohistochemical markers and to analyse the clinicopathological and immunohistochemical characteristics and the patterns of survival and relapse of the different subtypes. Methods. Two hundred and seventy-two patients diagnosed with breast cancer were classified into five subtypes: breast carcinomas of the basal type, HER2 type, luminal A type, luminal B type and normal. Results. The most frequent breast carcinomas were: luminal A type carcinomas (62.5%), luminal B type carcinomas (18%), HER2 type carcinomas (9.9%), basal type carcinomas (8.4%) and normal phenotype carcinomas (1.4%). Significantly and with greater frequency, the luminal type breast carcinomas proved to be well differentiated tumours, of small tumoral size, with negative axillary lymph nodes, at an early stage at the time of diagnosis, with high levels of BCL- 2 and a low Ki-67 proliferation index. On the contrary, the basal type and HER2 carcinomas presented larger tumours, poorly differentiated, greater ganglionar involvement and more advanced stages at the time of diagnosis. They expressed high Ki-67 proliferation indexes with greater frequency and were the subtypes that showed a worse prognosis on global survival and progression-free survival curves. Conclusion. Breast cancer classification based on immunohistochemical (IHC) parameters makes a better prognostic definition possible. Both the basal type and the HER2 type breast carcinomas present more unfavourable histopathological and IHC characteristics, as well as a worse survival and less relapse time, while the luminal type breast carcinomas show more benign characteristics and a better prognosis

    Observations of the First Electromagnetic Counterpart to a Gravitational-wave Source by the TOROS Collaboration

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    We present the results of prompt optical follow-up of the electromagnetic counterpart of the gravitational-wave event GW170817 by the Transient Optical Robotic Observatory of the South Collaboration. We detected highly significant dimming in the light curves of the counterpart (Δg = 0.17 ± 0.03 mag, Δr = 0.14 ± 0.02 mag, Δi = 0.10 ± 0.03 mag) over the course of only 80 minutes of observations obtained ∼35 hr after the trigger with the T80-South telescope. A second epoch of observations, obtained ∼59 hr after the event with the EABA 1.5 m telescope, confirms the fast fading nature of the transient. The observed colors of the counterpart suggest that this event was a \ blue kilonova\ relatively free of lanthanides
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