Unveiling radio halos in galaxy clusters in the LOFAR era

Giant radio halos are mega-parsec scale synchrotron sources detected in a fraction of massive and merging galaxy clusters. Radio halos provide one of the most important pieces of evidence for non-thermal components in large scale structure. Statistics of their properties can be used to discriminate among various models for their origin. Therefore, theoretical predictions of the occurrence of radio halos are important as several new radio telescopes are about to begin to survey the sky at low frequencies with unprecedented sensitivity. In this paper we carry out Monte Carlo simulations to model the formation and evolution of radio halos in a cosmological framework. We extend previous works on the statistical properties of radio halos in the context of the turbulent re-acceleration model. First we compute the fraction of galaxy clusters that show radio halos and derive the luminosity function of radio halos. Then, we derive differential and integrated number count distributions of radio halos at low radio frequencies with the main goal to explore the potential of the upcoming LOFAR surveys. By restricting to the case of clusters at redshifts <0.6, we find that the planned LOFAR all sky survey at 120 MHz is expected to detect about 350 giant radio halos. About half of these halos have spectral indices larger than 1.9 and substantially brighten at lower frequencies. If detected they will allow for a confirmation that turbulence accelerates the emitting particles. We expect that also commissioning surveys, such as MSSS, have the potential to detect about 60 radio halos in clusters of the ROSAT Brightest Cluster Sample and its extension (eBCS). These surveys will allow us to constrain how the rate of formation of radio halos in these clusters depends on cluster mass.Comment: 12 pages, 12 figures, accepted for publication in Astronomy and Astrophysic

First evidence of diffuse ultra-steep-spectrum radio emission surrounding the cool core of a cluster

Diffuse synchrotron radio emission from cosmic-ray electrons is observed at the center of a number of galaxy clusters. These sources can be classified either as giant radio halos, which occur in merging clusters, or as mini halos, which are found only in cool-core clusters. In this paper, we present the first discovery of a cool-core cluster with an associated mini halo that also shows ultra-steep-spectrum emission extending well beyond the core that resembles radio halo emission. The large-scale component is discovered thanks to LOFAR observations at 144 MHz. We also analyse GMRT observations at 610 MHz to characterise the spectrum of the radio emission. An X-ray analysis reveals that the cluster is slightly disturbed, and we suggest that the steep-spectrum radio emission outside the core could be produced by a minor merger that powers electron re-acceleration without disrupting the cool core. This discovery suggests that, under particular circumstances, both a mini and giant halo could co-exist in a single cluster, opening new perspectives for particle acceleration mechanisms in galaxy clusters

Anxious to see you: Neuroendocrine mechanisms of social vigilance and anxiety during adolescence.

Social vigilance is a behavioral strategy commonly used in adverse or changing social environments. In animals, a combination of avoidance and vigilance allows an individual to evade potentially dangerous confrontations while monitoring the social environment to identify favorable changes. However, prolonged use of this behavioral strategy in humans is associated with increased risk of anxiety disorders, a major burden for human health. Elucidating the mechanisms of social vigilance in animals could provide important clues for new treatment strategies for social anxiety. Importantly, during adolescence the prevalence of social anxiety increases significantly. We hypothesize that many of the actions typically characterized as anxiety behaviors begin to emerge during this time as strategies for navigating more complex social structures. Here, we consider how the social environment and the pubertal transition shape neural circuits that modulate social vigilance, focusing on the bed nucleus of the stria terminalis and prefrontal cortex. The emergence of gonadal hormone secretion during adolescence has important effects on the function and structure of these circuits, and may play a role in the emergence of a notable sex difference in anxiety rates across adolescence. However, the significance of these changes in the context of anxiety is still uncertain, as not enough studies are sufficiently powered to evaluate sex as a biological variable. We conclude that greater integration between human and animal models will aid the development of more effective strategies for treating social anxiety

Approximation-Based Fault Tolerance in Image Processing Applications

Image processing applications exhibit an intrinsic degree of fault tolerance due to i) the redundant nature of images, and ii) the possible ability of the consumers of the application output to effectively carry out their task even when it is slightly corrupted. In this application scenario the classical Duplication with Comparison (DWC) scheme, that rejects images (and requires re-executions) when the two replicas' outputs differ in a per-pixel comparison, may be over-conservative. In this article, we propose a novel lightweight fault tolerant scheme specifically tailored for image processing applications. The proposed scheme enhances the state-of-the-art by: i) improving the DWC scheme by replacing one of the two exact replicas with an approximated counterpart, and ii) allowing to distinguish between usable and unusable images instead of corrupted and uncorrupted ones by means of a Convolutional Neural Network-based checker. To tune the proposed scheme we introduce a specific design methodology that optimizes both execution time and fault detection capability of the hardened system. We report the results of the application of the proposed approach on two case studies; our proposal achieves an average execution time reduction larger than 30% w.r.t. the DWC with re-execution, and less than 4% misclassified unusable images

An unusual case of unilateral sinus disease may reveal the presence of a retained foreign body

Introduction: Differential diagnosis of unilateral sinus disease (USD) is important in clinical practice as it can be broad, and for which timely and effective treatment is important. With this report we would like to present a case of a patient with a foreign body retained in the left maxillary sinus for eight years. Presentation of case: A 50-year-old gardener referred to have been injured on the job in 2010. Even though he was wearing his safety helmet with face shield and earmuffs, he had the sensation to have been hit by an object coming from the soil, while he was using his grass trimmer. However, the patient was asymptomatic with no complications. After eight years, the man started experiencing left nasal obstruction associated with purulent discharge and ipsilateral headache. A fetid odor coming from inside the nose and described as “the carcass of a dog” led him to seek medical attention. The patient underwent a functional endoscopic sinus surgery (FESS) with septoplasty and a foreign body, consisting of a metal nail, was retrieved. Discussion: This case highlights a two key learning points. The first one concerns occupational safety measures; full-face shield helmets are the best option and should be employed in order to avoid the penetration of any possibly dangerous materials. Secondly, grass trimmers with more sophisticated designs are required in order to prevent injuries like this. Conclusions: Besides being peculiar because of the onset of clinical symptoms, this case report highlights the importance of full-face shield helmets and certified machinery

once weekly administration of high dosage etanercept in patients with plaque psoriasis results of a pilot experience power study

Abstract Etanercept is a soluble tumour necrosis factor receptor fusion protein which is approved for the treatment of plaque psoriasis at the dose of either 25mg twice weekly (BIW) or, for the initial 12 weeks, 50mg BIW. Alternative dosing regimens have not been evaluated in psoriasis. In this study, we compare the efficacy and tolerability of two etanercept dosing regimens--50mg BIW and 100mg once weekly (OW)--for 12 weeks in 108 patients with moderate-to-severe recalcitrant psoriasis. Efficacy measures included Psoriasis Area and Severity Index (PASI), severity of pruritus recorded on a visual analogue scale (VAS) and the influence on quality of life assessed by means of Dermatology Life Quality Index (DLQI). Both etanercept regimens caused a significant change in all the efficacy parameters after 4 weeks and 12 weeks, at a comparable rate. At week 12, a PASI improvement of at least 50% from baseline (PASI 50) was achieved by 74% of patients treated with 50mg BIW and 78% of patients treated with 100mg OW. A PASI 75 response was obtained in 54% and 50% of patients treated with 50mg BIW and 100mg OW, respectively. Treatment was well tolerated with similar type and frequency of adverse events between the two groups

COVID-19: what happened to all of the otolaryngology emergencies?

To the Editor, COVID-19 is a global pandemic caused by the novel coronavirus SARS-CoV-2, and Italy was the first European country to experience a large-scale outbreak. With this, every aspect of healthcare, the economy, and society has been deeply affected in Italy, so much so that fundamental changes are expected in the post-COVID-19 era. One aspect is that access to emergency care in Otolaryngology (ORL) patients has already changed in the month following the onset of the COVID-19 outbreak, and, seemingly, many non-COVID illnesses have been disappearing. Although the government did not enact any limitations or prohibitions to emergency access for patients afflicted by acute ORL pathologies, the number of daily urgent consultations to the ORL Departments in Bari and Foggia University Hospitals has significantly reduced and, on some days, was even zero. One possible reason for this change may be patients’ fear of acquiring a nosocomial COVID-19 infection. Even so, it is difficult to believe that some acute diseases, such as massive epistaxis, otitis, or pharyngotonsillitis, could have occurred so rarely or not at all or, alternately, could have been treated at home by patients or their families. Rather, most certainly, primary care physicians, who have been performing telehealth consultations in accordance with the guidelines from the Higher Institute of Health (ISS), have been providing an invaluable service [1]; it is posited that patients who received primary care services this way may have been able to delay or even forego specialist evaluation. This telehealth treatment has not only helped to keep patients at home but has provided other benefits and should be considered in the future. Table ​Table11 shows data regarding the number of emergency department consultations by diagnosis in the 30 days preceding (from February 8th to March 8th, 2020) and 30 days following (from March 9th to April 9th, 2020) the onset of the COVID-19 outbreak at the two main tertiary referral centers in the Puglia region, as well as the percentage reduction for each diagnosis. The data revealed an overall decrease in the number of ORL emergency consultations by 80.8%. Of note, reductions were noted across all subspecialties. Although some illnesses, such as rhinitis, sinusitis, uvular edema, and tinnitus, do not usually require immediate attention, it is more difficult to explain the large reduction, ranging from 80.2% to 88.9%, of other diagnoses, such as vertigo, epistaxis, sudden hearing loss, otitis media, and peritonsillar abscesses, which often merit urgent ORL consultations. The reduction of some diagnoses may be the consequence of national lockdown orders. For example, the 84.6% reduction in the number of nasal bone fractures may be related to the near-absence of motor vehicle accidents reported during this time. In contrast, it is more difficult to explain the reduction of other acute diseases such as sudden hearing loss, whose frequency decreased 83.3%, especially when compared to non-disease conditions, such as cerumen impaction, whose reduction in presentation, interestingly, was slightly more modest at 73.7%. A reduction in the number of emergency ORL consultations by 80.8% during the COVID-19 pandemic creates new paradigms for the future. Over the past few decades, the workload performed by healthcare personnel in emergency departments has increased, and some have even noted a reduction in morale and job satisfaction, as their responsibilities include intervening in not only true emergencies but also managing many patients with non-acute complaints. One possible exacerbating factor is the length of waitlists to access outpatient care in the Italian National Healthcare System (NHS), as some patients may have to wait for months to see an otolaryngologist. This situation has motivated many to seek care in the emergency department to skip wait times and receive specialty evaluation and treatment without charge. Decreasing the utilization of emergency department services by improving access to primary care services has been a long-term aim, articulated since at least 1958, when physicians working at Hartford Hospital published a pioneering piece in The New England Journal of Medicine [2] that showed that only a minimum number of patients who visited the emergency department required inpatient care. At that time, proposed solutions were to increase utilization of outpatient care and to educate patients to seek a preliminary triage consultation with their family physicians; it is possible that the COVID-19 outbreak is pushing our current society in a similar direction. Certainly, the priority now is to fight the pandemic, but in time, many aspects of healthcare should be reviewed and better organization through telemedicine sought [3]. Hopefully, patients will have learnt to more appropriately utilize the numerous resources offered by the Italian NHS for all of its patients

Signatures from a merging galaxy cluster and its AGN population : LOFAR observations of Abell 1682

Reproduced with permission from Astronomy & Astrophysics. © 2019 ESOWe present LOFAR data from 110-180 MHz of the merging galaxy cluster Abell 1682, alongside archival optical, radio, and X-ray data. Our images of 6 arcsec in resolution at low frequencies reveal new structures associated with numerous radio galaxies in the cluster. At a resolution of 20 arcsec we see diffuse emission throughout the cluster over hundreds of kiloparsecs, indicating particle acceleration mechanisms are in play as a result of the cluster merger event and powerful active galactic nuclei. We show that a significant part of the cluster emission is from an old radio galaxy with very steep spectrum emission (having a spectral index of α < -2.5). Furthermore, we identify a new region of diffuse steep-spectrum emission (α < -1.1) as a candidate for a radio halo which is co-spatial with the centre of the cluster merger. We suggest its origin as a population of old and mildly relativistic electrons left over from radio galaxies throughout the cluster which have been re-accelerated to higher energies by shocks and turbulence induced by the cluster merger event. We also note the discovery of six new giant radio galaxies in the vicinity of Abell 1682.Peer reviewedFinal Accepted Versio

KAP1 targets actively transcribed genomic loci to exert pleomorphic effects on RNA polymerase II activity

KAP1 (KRAB-associated protein 1) is best known as a co-repressor responsible for inducing heterochromatin formation, notably at transposable elements. However, it has also been observed to bind the transcription start site of actively expressed genes. To address this paradox, we characterized the protein interactome of KAP1 in the human K562 erythro-leukaemia cell line. We found that the regulator can associate with a wide range of nucleic acid binding proteins, nucleosome remodellers, chromatin modifiers and other transcription modulators. We further determined that KAP1 is recruited at actively transcribed polymerase II promoters, where its depletion resulted in pleomorphic effects, whether expression of these genes was normally constitutive or inducible, consistent with the breadth of possible KAP1 interactors. This article is part of a discussion meeting issue 'Crossroads between transposons and gene regulation'

Entropy perturbations and large-scale magnetic fields

An appropriate gauge-invariant framework for the treatment of magnetized curvature and entropy modes is developed. It is shown that large-scale magnetic fields, present after neutrino decoupling, affect curvature and entropy perturbations. The evolution of different magnetized modes is then studied across the matter-radiation transition both analytically and numerically. From the observation that, after equality (but before decoupling) the (scalar) Sachs-Wolfe contribution must be (predominantly) adiabatic, constraints on the magnetic power spectra are deduced. The present results motivate the experimental analysis of more general initial conditions of CMB anisotropies (i.e. mixtures of magnetized adiabatic and isocurvature modes during the pre-decoupling phase). The role of the possible correlations between the different components of the fluctuations is partially discussed.Comment: 43 pages, 9 figure