Constraints on redshifts of blazars from extragalactic background light attenuation using Fermi-LAT data

The extragalactic high-energy $\gamma$-ray sky is dominated by blazars, which are active galactic nuclei with their jets pointing towards us. Distance measurements are of fundamental importance yet for some of these sources are challenging because any spectral signature from the host galaxy may be outshone by the non-thermal emission from the jet. In this paper, we present a method to constrain redshifts for these sources that relies only on data from the Large Area Telescope on board the Fermi Gamma-ray Space Telescope. This method takes advantage of the signatures that the pair-production interaction between photons with energies larger than approximately 10 GeV and the extragalactic background light leaves on $\gamma$-ray spectra. We find upper limits for the distances of 303 $\gamma$-ray blazars, classified as 157 BL Lacertae objects, 145 of uncertain class, and 1 flat-spectrum-radio quasar, whose redshifts are otherwise unknown. These derivations can be useful for planning observations with imaging atmospheric Cherenkov telescopes and also for testing theories of supermassive black hole evolution. Our results are applied to estimate the detectability of these blazars with the future Cherenkov Telescope Array, finding that at least 21 of them could be studied in a reasonable exposure of 20 h.Comment: 13 pages, 7 figures, 1 table; Accepted by MNRA

The Global Campaign (GC) to Reduce the Burden of Headache Worldwide. The International Team for Specialist Education (ITSE).

The social perception of headache, everywhere at low levels in industrialised countries, becomes totally absent in developing ones. Headache disorders came into the World Health Organization\u27s strategic priorities after publication of the 2001 World Health Report. Among the leading causes of disability, migraine was ranked 19th for adults of both sexes together and 12th for females. The Global Campaign (GC) to Reduce the Burden of Headache Worldwide was planned by the major international headache organizations together with WHO in order to identify and remove those cultural, social and educational barriers recognised as responsible factors for the inadequate treatment of headache disorders worldwide. Within the GC activities, the education of the medical body will represents a central pillar. An International Team for Specialist Education (ITSE) has been created to train physicians from all over the world through the acquisition of a university level Master Degree in Headache Medicine. Once trained as headache specialists, physicians will become trainers, offering education in this field to other health care providers in their own countries. In this way they will give life to a cultural chain raising awareness locally of headache, its burden and its medical control

The headache under-response to treatment (HURT) questionnaire, an outcome measure to guide follow-up in primary care: development, psychometric evaluation and assessment of utility

Background: Headache disorders are both common and burdensome but, given the many people affected, provision of health care to all is challenging. Structured headache services based in primary care are the most efficient, equitable and cost-effective solution but place responsibility for managing most patients on health-care providers with limited training in headache care. The development of practical management aids for primary care is therefore a purpose of the Global Campaign against Headache. This manuscript presents an outcome measure, the Headache Under-Response to Treatment (HURT) questionnaire, describing its purpose, development, psychometric evaluation and assessment for clinical utility. The objective was a simple-to-use instrument that would both assess outcome and provide guidance to improving outcome, having utility across the range of headache disorders, across clinical settings and across countries and cultures. Methods: After literature review, an expert consensus group drawn from all six world regions formulated HURT through item development and item reduction using item-response theory. Using the American Migraine Prevalence and Prevention Study’s general-population respondent panel, two mailed surveys assessed the psychometric properties of HURT, comparing it with other instruments as external validators. Reliability was assessed in patients in two culturally-contrasting clinical settings: headache specialist centres in Europe (n = 159) and primary-care centres in Saudi Arabia (n = 40). Clinical utility was assessed in similar settings (Europe n = 201; Saudi Arabia n = 342). Results: The final instrument, an 8-item self-administered questionnaire, addressed headache frequency, disability, medication use and effect, patients’ perceptions of headache “control” and their understanding of their diagnoses. Psychometric evaluation revealed a two-factor model (headache frequency, disability and medication use; and medication efficacy and headache control), with scale properties apparently stable across disorders and correlating well and in the expected directions with external validators. The literature review found few instruments linking assessment to clinical advice or suggested actions: HURT appeared to fill this gap. In European specialist care, it showed utility as an outcome measure across headache disorders. In Saudi Arabian primary care, HURT (translated into Arabic) was reliable and responsive to clinical change. Conclusions: With demonstrated validity and clinical utility across disorders, cultures and settings, HURT is available for clinical and research purposes

CGRP en migraña: de la fisiopatología a la terapéutica

Introducción En los últimos años se ha observado que moléculas como el péptido relacionado con el gen de la calcitonina (CGRP) y, en menor grado, el péptido activador de la adenilato-ciclasa pituitaria estaban elevadas durante los ataques de migraña y en la migraña crónica tanto en líquido cefalorraquídeo como en suero y que su reducción farmacológica tenía una significación clínica con una mejoría en la migraña de los pacientes. Es lógico por tanto que una de las principales líneas de investigación en migraña se base en el papel del CGRP en la fisiopatología de esta entidad. Desarrollo Desde el Grupo de Estudio de Cefaleas de la Sociedad Española de Neurología nos planteamos la redacción de este documento, cuyo objetivo es abordar, basándonos en la evidencia publicada, cuestiones tan importantes como el papel del CGRP en la fisiopatología de la migraña, el mecanismo de acción de los anticuerpos monoclonales y de los gepantes, el análisis crítico de los resultados de los diferentes estudios, el perfil del paciente que podría ser candidato al tratamiento con anticuerpos monoclonales y su impacto en términos de farmacoeconomía. Conclusiones El desarrollo clínico de los gepantes, antagonistas del CGRP, para el tratamiento agudo del ataque de migraña y de los anticuerpos monoclonales contra ligando y contra el receptor del CGRP ofrecen resultados esperanzadores para nuestros pacientes. Introduction It has been observed in recent years that levels of such molecules as calcitonin gene–related peptide (CGRP) and, to a lesser extent, the pituitary adenylate cyclase–activating peptide are elevated during migraine attacks and in chronic migraine, both in the cerebrospinal fluid and in the serum. Pharmacological reduction of these proteins is clinically significant, with an improvement in patients’ migraines. It therefore seems logical that one of the main lines of migraine research should be based on the role of CGRP in the pathophysiology of this entity. Development The Spanish Society of Neurology''s Headache Study Group decided to draft this document in order to address the evidence on such important issues as the role of CGRP in the pathophysiology of migraine and the mechanism of action of monoclonal antibodies and gepants; and to critically analyse the results of different studies and the profile of patients eligible for treatment with monoclonal antibodies, and the impact in terms of pharmacoeconomics. Conclusions The clinical development of gepants, which are CGRP antagonists, for the acute treatment of migraine attacks, and CGRP ligand and receptor monoclonal antibodies offer promising results for these patients

Constraints on axion-like particles with the Perseus Galaxy Cluster with MAGIC

Axion-like particles (ALPs) are pseudo-Nambu-Goldstone bosons that emerge in various theories beyond the standard model. These particles can interact with high-energy photons in external magnetic fields, influencing the observed gamma-ray spectrum. This study analyzes 41.3 hrs of observational data from the Perseus Galaxy Cluster collected with the MAGIC telescopes. We focused on the spectra the radio galaxy in the center of the cluster: NGC 1275. By modeling the magnetic field surrounding this target, we searched for spectral indications of ALP presence. Despite finding no statistical evidence of ALP signatures, we were able to exclude ALP models in the sub-micro electronvolt range. Our analysis improved upon previous work by calculating the full likelihood and statistical coverage for all considered models across the parameter space. Consequently, we achieved the most stringent limits to date for ALP masses around 50 neV, with cross sections down to $g_{a\gamma} = 3 \times 10^{-12}$ GeV$^{-1}$.Comment: 25 pages, 10 figures, accepted for publication in Physics of the Dark Univers

The variability patterns of the TeV blazar PG 1553+113 from a decade of MAGIC and multi-band observations

PG 1553+113 is one of the few blazars with a convincing quasi-periodic emission in the gamma-ray band. The source is also a very high-energy (VHE; >100 GeV) gamma-ray emitter. To better understand its properties and identify the underlying physical processes driving its variability, the MAGIC Collaboration initiated a multiyear, multiwavelength monitoring campaign in 2015 involving the OVRO 40-m and Medicina radio telescopes, REM, KVA, and the MAGIC telescopes, Swift and Fermi satellites, and the WEBT network. The analysis presented in this paper uses data until 2017 and focuses on the characterization of the variability. The gamma-ray data show a (hint of a) periodic signal compatible with literature, but the X-ray and VHE gamma-ray data do not show statistical evidence for a periodic signal. In other bands, the data are compatible with the gamma-ray period, but with a relatively high p-value. The complex connection between the low and high-energy emission and the non-monochromatic modulation and changes in flux suggests that a simple one-zone model is unable to explain all the variability. Instead, a model including a periodic component along with multiple emission zones is required.Comment: Accepted for publication in Monthly Notices of the Royal Astronomical Society. 19 pages, 9 figures. Corresponding authors: Elisa Prandini, Antonio Stamerra, Talvikki Hovatt

Multi-year characterisation of the broad-band emission from the intermittent extreme BL Lac 1ES~2344+514

The BL Lac 1ES 2344+514 is known for temporary extreme properties (e.g., a shift of the synchrotron SED peak energy $\nu_{synch,p}$ above 1keV). While those extreme states were so far observed only during high flux levels, additional multi-year observing campaigns are required to achieve a coherent picture. Here, we report the longest investigation of the source from radio to VHE performed so far, focusing on a systematic characterisation of the intermittent extreme states. While our results confirm that 1ES 2344+514 typically exhibits $\nu_{synch,p}>$1keV during elevated flux periods, we also find periods where the extreme state coincides with low flux activity. A strong spectral variability thus happens in the quiescent state, and is likely caused by an increase of the electron acceleration efficiency without a change in the electron injection luminosity. We also report a strong X-ray flare (among the brightest for 1ES 2344+514) without a significant shift of $\nu_{synch,p}$. During this particular flare, the X-ray spectrum is among the softest of the campaign. It unveils complexity in the spectral evolution, where the common harder-when-brighter trend observed in BL Lacs is violated. During a low and hard X-ray state, we find an excess of the UV flux with respect to an extrapolation of the X-ray spectrum to lower energies. This UV excess implies that at least two regions contribute significantly to the infrared/optical/ultraviolet/X-ray emission. Using the simultaneous MAGIC, XMM-Newton, NuSTAR, and AstroSat observations, we argue that a region possibly associated with the 10 GHz radio core may explain such an excess. Finally, we investigate a VHE flare, showing an absence of simultaneous variability in the 0.3-2keV band. Using a time-dependent leptonic modelling, we show that this behaviour, in contradiction to single-zone scenarios, can instead be explained by a two-component model.Comment: Accepted for publication in Astronomy & Astrophysic

Sensitivity of the Cherenkov Telescope Array to spectral signatures of hadronic PeVatrons with application to Galactic Supernova Remnants

The local Cosmic Ray (CR) energy spectrum exhibits a spectral softening at energies around 3~PeV. Sources which are capable of accelerating hadrons to such energies are called hadronic PeVatrons. However, hadronic PeVatrons have not yet been firmly identified within the Galaxy. Several source classes, including Galactic Supernova Remnants (SNRs), have been proposed as PeVatron candidates. The potential to search for hadronic PeVatrons with the Cherenkov Telescope Array (CTA) is assessed. The focus is on the usage of very high energy $\gamma$-ray spectral signatures for the identification of PeVatrons. Assuming that SNRs can accelerate CRs up to knee energies, the number of Galactic SNRs which can be identified as PeVatrons with CTA is estimated within a model for the evolution of SNRs. Additionally, the potential of a follow-up observation strategy under moonlight conditions for PeVatron searches is investigated. Statistical methods for the identification of PeVatrons are introduced, and realistic Monte--Carlo simulations of the response of the CTA observatory to the emission spectra from hadronic PeVatrons are performed. Based on simulations of a simplified model for the evolution for SNRs, the detection of a $\gamma$-ray signal from in average 9 Galactic PeVatron SNRs is expected to result from the scan of the Galactic plane with CTA after 10 hours of exposure. CTA is also shown to have excellent potential to confirm these sources as PeVatrons in deep observations with $\mathcal{O}(100)$ hours of exposure per source.Comment: 34 pages, 16 figures, Accepted for publication in Astroparticle Physic

Italian guidelines for primary headaches: 2012 revised version

The first edition of the Italian diagnostic and therapeutic guidelines for primary headaches in adults was published in J Headache Pain 2(Suppl. 1):105–190 (2001). Ten years later, the guideline committee of the Italian Society for the Study of Headaches (SISC) decided it was time to update therapeutic guidelines. A literature search was carried out on Medline database, and all articles on primary headache treatments in English, German, French and Italian published from February 2001 to December 2011 were taken into account. Only randomized controlled trials (RCT) and meta-analyses were analysed for each drug. If RCT were lacking, open studies and case series were also examined. According to the previous edition, four levels of recommendation were defined on the basis of levels of evidence, scientific strength of evidence and clinical effectiveness. Recommendations for symptomatic and prophylactic treatment of migraine and cluster headache were therefore revised with respect to previous 2001 guidelines and a section was dedicated to non-pharmacological treatment. This article reports a summary of the revised version published in extenso in an Italian version

Chronic migraine plus medication overuse headache: two entities or not?

Chronic migraine (CM) represents migraine natural evolution from its episodic form. It is realized through a chronicization phase that may require months or years and varies from patient to patient. The transition to more frequent attacks pattern is influenced by lifestyle, life events, comorbid conditions and personal genetic terrain, and it often leads to acute drugs overuse. Medication overuse headache (MOH) may complicate every type of headache and all the drugs employed for headache treatment can cause MOH. The first step in the management of CM complicated by medication overuse must be the withdrawal of the overused drugs and a detoxification treatment. The goal is not only to detoxify the patient and stop the chronic headache but also to improve responsiveness to acute or prophylactic drugs. Different methods have been suggested: gradual or abrupt withdrawal; home treatment, hospitalization, or a day-hospital setting; re-prophylaxes performed immediately or at the end of the wash-out period. Up to now, only topiramate and local injection of onabotulinumtoxinA have shown efficacy as therapeutic agents for re-prophylaxis after detoxification in patients with CM with and without medication overuse. Although the two treatments showed similar efficacy, onabotulinumtoxinA is associated with a better adverse events profile. Recently, the Phase III Research Evaluating Migraine Prophylaxis Therapy (PREEMPT) clinical program proved that patients with CM, even those with MOH, are the ones most likely to benefit from onabotulinumtoxinA treatment. Furthermore, it provided an injection paradigm that can be used as a guide for a correct administration of onabotulinumtoxinA