Search for X-ray emission from subdwarf B stars with compact companion candidates

Stellar evolutionary models predict that most of the early type subdwarf stars in close binary systems have white dwarf companions. More massive companions, such as neutron stars or black holes, are also expected in some cases. The presence of compact stars in these systems can be revealed by the detection of X-rays powered by accretion of the subdwarf's stellar wind or by surface thermal emission. Using the Swift satellite, we carried out a systematic search for X-ray emission from a sample of twelve subdwarf B stars which, based on optical studies, have been suggested to have degenerate companions. None of our targets was detected, but the derived upper limits provide one of the few observational constraints on the stellar winds of early type subdwarfs. If the presence of neutron star companions is confirmed, our results constrain the mass loss rates of some of these subdwarf B stars to values <10^{-13}-10^{-12} Msun/yr.Comment: Accepted for publication in Astronomy and Astrophysic

Two new catalogs of blazar candidates in the WISE infrared sky

We present two catalogs of radio-loud candidate blazars whose WISE mid-infrared colors are selected to be consistent with the colors of confirmed gamma-ray emitting blazars. The first catalog is the improved and expanded release of the WIBRaLS catalog presented by D'Abrusco et al. (2014): it includes sources detected in all four WISE filters, spatially cross-matched with radio source in one of three radio surveys and radio-loud based on their q22 spectral parameter. WIBRaLS2 includes 9541 sources classified as BL Lacs, FSRQs or mixed candidates based on their WISE colors. The second catalog, called KDEBLLACS, based on a new selection technique, contains 5579 candidate BL Lacs extracted from the population of WISE sources detected in the first three WISE passbands ([3.4], [4.6] and [12]) only, whose mid-infrared colors are similar to those of confirmed, gamma-ray BL Lacs. KDBLLACS members area also required to have a radio counterpart and be radio-loud based on the parameter q12, defined similarly to q22 used for the WIBRaLS2. We describe the properties of these catalogs and compare them with the largest samples of confirmed and candidate blazars in the literature. We crossmatch the two new catalogs with the most recent catalogs of gamma-ray sources detected by Fermi LAT instrument. Since spectroscopic observations of candidate blazars from the first WIBRaLS catalog within the uncertainty regions of gamma-ray unassociated sources confirmed that ~90% of these candidates are blazars, we anticipate that these new catalogs will play again an important role in the identification of the gamma-ray sky.Comment: 20 pages, 7 figures. Accepted for publication in The Astrophysical Journal Supplement Serie

Catecholamine-induced Takotsubo syndrome: a case series

Background: Catecholamine-induced Takotsubo Syndrome (cat-TS) is a type of secondary Takotsubo syndrome, characterized by rapid onset of symptoms, high rate of complications during the acute phase, good short-term prognosis, and frequent apical sparing at echocardiogram. We present two clinical cases of cat-TS treated in our department. Case summary: Case one: 78-year-old man, admitted to Ear Nose and Throat Unit for surgical removal of oral squamous cellular carcinoma. During surgery, the occurrence of hypotensive episode was treated with catecholamines. After surgery, the occurrence of atrial fibrillation was followed by evidence of phasic increase of troponin levels and akinesia of midventricular segments. Angiography showed the absence of significant coronary stenoses, and during hospital stay, we observed rapid recovery of wall motion abnormalities. Case two: 64-year-old woman, admitted for hysteropexy surgery, during which cardiac arrest occurred, treated with epinephrine i.v.1 mg and DC shock. Two hours after resuscitation, the patient developed pulmonary oedema, troponin levels increased progressively, and the echocardiogram demonstrated hypokinesia in all midventricular segments with apical sparing. Afterwards, an urgent angiography highlighted normal coronary anatomy. Cardiac magnetic resonance imaging (MRI) revealed oedema corresponding to hypokinetic areas. On the seventh day, echocardiogram showed a complete remission of wall motion abnormalities. Discussion: These cases warn the physicians about the importance of routinely screening myocardial impairment through clinical assessment, electrocardiogram (ECG) monitoring, and serial cardiac troponin testing after catecholamine i.v. bolus administration. In case of alterations of these exams, performing a prompt echocardiogram allows early detection of cat-TS, to provide immediate suitable medical support and avoid complications

The Highly Energetic Expansion of SN2010bh Associated with GRB 100316D

We present the spectroscopic and photometric evolution of the nearby (z = 0.059) spectroscopically confirmed type Ic supernova, SN 2010bh, associated with the soft, long-duration gamma-ray burst (X-ray flash) GRB 100316D. Intensive follow-up observations of SN 2010bh were performed at the ESO Very Large Telescope (VLT) using the X-shooter and FORS2 instruments. Owing to the detailed temporal coverage and the extended wavelength range (3000--24800 A), we obtained an unprecedentedly rich spectral sequence among the hypernovae, making SN 2010bh one of the best studied representatives of this SN class. We find that SN 2010bh has a more rapid rise to maximum brightness (8.0 +/- 1.0 rest-frame days) and a fainter absolute peak luminosity (L_bol~3e42 erg/s) than previously observed SN events associated with GRBs. Our estimate of the ejected (56)Ni mass is 0.12 +/- 0.02 Msun. From the broad spectral features we measure expansion velocities up to 47,000 km/s, higher than those of SNe 1998bw (GRB 980425) and 2006aj (GRB 060218). Helium absorption lines He I lambda5876 and He I 1.083 microm, blueshifted by ~20,000--30,000 km/s and ~28,000--38,000 km/s, respectively, may be present in the optical spectra. However, the lack of coverage of the He I 2.058 microm line prevents us from confirming such identifications. The nebular spectrum, taken at ~186 days after the explosion, shows a broad but faint [O I] emission at 6340 A. The light-curve shape and photospheric expansion velocities of SN 2010bh suggest that we witnessed a highly energetic explosion with a small ejected mass (E_k ~ 1e52 erg and M_ej ~ 3 Msun). The observed properties of SN 2010bh further extend the heterogeneity of the class of GRB supernovae.Comment: 37 pages and 12 figures (one-column pre-print format), accepted for publication in Ap

Long-Term Outcome and Risk Stratification in Dilated Cardiolaminopathies

n/

PixDD: a multi-pixel silicon drift detector for high-throughput spectral-timing studies

The Pixelated silicon Drift Detector (PixDD) is a two-dimensional multi-pixel X-ray sensor based on the technology of Silicon Drift Detectors, designed to solve the dead time and pile-up issues of photon-integrating imaging detectors. Read out by a two-dimensional self-triggering Application-Specific Integrated Circuit named RIGEL, to which the sensor is bump-bonded, it operates in the 0:5 — 15 keV energy range and is designed to achieve single-photon sensitivity and good spectroscopic capabilities even at room temperature or with mild cooling (< 150 eV resolution at 6 keV at 0 °C). The paper reports on the design and performance tests of the 128-pixel prototype of the fully integrated system

Big Earth Data for Cultural Heritage in the Copernicus Era

Digital data is stepping in its golden age characterized by an increasing growth of both classical and emerging big earth data along with trans- and multidisciplinary methodological approaches and services addressed to the study, preservation and sustainable exploitation of cultural heritage (CH). The availability of new digital technologies has opened new possibilities, unthinkable only a few years ago for cultural heritage. The currently available digital data, tools and services with particular reference to Copernicus initiatives make possible to characterize and understand the state of conservation of CH for preventive restoration and opened up a frontier of possibilities for the discovery of archaeological sites from above and also for supporting their excavation, monitoring and preservation. The different areas of intervention require the availability and integration of rigorous information from different sources for improving knowledge and interpretation, risk assessment and management in order to make more successful all the actions oriented to the preservation of cultural properties. One of the biggest challenges is to fully involve the citizen also from an emotional point of view connecting “pixels with people” and “bridging” remote sensing and social sensing

Virological and immunological features of SARS-CoV-2-infected children who develop neutralizing antibodies

As the global COVID-19 pandemic progresses, it is paramount to gain knowledge on adaptive immunity to SARS-CoV-2 in children to define immune correlates of protection upon immunization or infection. We analyzed anti-SARS-CoV-2 antibodies and their neutralizing activity (PRNT) in 66 COVID-19-infected children at 7 (\ub12) days after symptom onset. Individuals with specific humoral responses presented faster virus clearance and lower viral load associated with a reduced in&nbsp;vitro infectivity. We demonstrated that the frequencies of SARS-CoV-2-specific CD4+CD40L+ T&nbsp;cells and Spike-specific B cells were associated with the anti-SARS-CoV-2 antibodies and the magnitude of neutralizing activity. The plasma proteome confirmed the association between cellular and humoral SARS-CoV-2 immunity, and PRNT+ patients show higher viral signal transduction molecules (SLAMF1, CD244, CLEC4G). This work sheds lights on cellular and humoral anti-SARS-CoV-2 responses in children, which may drive future vaccination trial endpoints and quarantine measures policies

Distribution, Population Biology, and Trophic Ecology of the Deepwater Demersal Fish Halosauropsis macrochir (Pisces: Halosauridae) on the Mid-Atlantic Ridge

Halosauropsis macrochir ranked amongst the most abundant and widespread demersal fishes on the mid-Atlantic Ridge of the North Atlantic (Iceland-Azores) with greatest abundance at 1700–3500 m. All sizes, ranging from 10–76 cm total length, occurred in the area without any apparent spatial pattern or depth trend. Using otolith sections displaying growth increments assumed to represent annuli, the age range recorded was 2–36 years, but most individuals were <20 years. Length and weight at age data were used to fit growth models. No differences between sexes in length and weight at age were observed. The majority of samples had a surplus of males. Diet analysis showed that H. macrochir feeds on Crustacea, Teleostei, Polychaeta, and Cephalopoda, but few prey could be identified to lower taxonomical levels. The mid-Atlantic Ridge constitutes a major portion of the North Atlantic living space of the abyssal halosaur where it completes its full life cycle, primarily as an actively foraging euryophagous micronekton/epibenthos and infauna feeder, becoming a partial piscivore with increasing size