MAGIC observations of very high energy gamma-rays from HESS J1813-178

Recently, the HESS collaboration has reported the detection of gamma-ray emission above a few hundred GeV from eight new sources located close to the Galactic Plane. The source HESS J1813-178 has sparked particular interest, as subsequent radio observations imply an association with SNR G12.82-0.02. Triggered by the detection in VHE gamma-rays, a positionally coincident source has also been found in INTEGRAL and ASCA data. In this Letter we present MAGIC observations of HESS J1813-178, resulting in the detection of a differential gamma-ray flux consistent with a hard-slope power law, described as dN/(dA dt dE) = (3.3+/-0.5)*10^{-12} (E/TeV)^{-2.1+/-0.2} cm^(-2)s^(-1)TeV^(-1). We briefly discuss the observational technique used, the procedure implemented for the data analysis, and put this detection in the perspective of multifrequency observations.Comment: Accepted by ApJ Letter

Small-scale solar magnetic fields

As we resolve ever smaller structures in the solar atmosphere, it has become clear that magnetism is an important component of those small structures. Small-scale magnetism holds the key to many poorly understood facets of solar magnetism on all scales, such as the existence of a local dynamo, chromospheric heating, and flux emergence, to name a few. Here, we review our knowledge of small-scale photospheric fields, with particular emphasis on quiet-sun field, and discuss the implications of several results obtained recently using new instruments, as well as future prospects in this field of research.Comment: 43 pages, 18 figure

Fingolimod: therapeutic mechanisms and ocular adverse effects.

Fingolimod is an oral immunomodulating drug used in the management of relapsing-remitting multiple sclerosis (RRMS). We aim to review the published literature on ocular manifestations of fingolimod therapy and their possible underlying mechanisms. The therapeutic effects of fingolimod are mediated via sphingosine receptors, which are found ubiquitously in various organs, including lymphoid cells, central nervous system, cardiac myocytes, and smooth muscle cells. Fingolimod-associated macular oedema (FAME) is the most common ocular side effect but retinal haemorrhages and retinal vein occlusion can occur. The visual consequences appear to be mild and, in cases of FAME, resolution is often attained with discontinuation of therapy. However, in cases of retinal vein occlusion, discontinuation of fingolimod alone may not be sufficient and intra-vitreal therapy may be required. We also propose a pragmatic service pathway for monitoring patients on fingolimod therapy, which includes stratifying them by risk and visual acuity

Variable Very High Energy Gamma-ray Emission from the Microquasar LS I +61 303

Microquasars are binary star systems with relativistic radio-emitting jets. They are potential sources of cosmic rays and laboratories for elucidating the physics of relativistic jets. Here we report the detection of variable gamma-ray emission above 100 gigaelectron volts from the microquasar LS I +61 303. Six orbital cycles were recorded. Several detections occur at a similar orbital phase, suggesting the emission is periodic. The strongest gamma-ray emission is not observed when the two stars are closest to one another, implying a strong orbital modulation of the emission or the absorption processes.Comment: 11 pages with 4 figure

Variable Very High Energy Gamma-ray Emission from the Microquasar LS I +61 303

Microquasars are binary star systems with relativistic radio-emitting jets. They are potential sources of cosmic rays and laboratories for elucidating the physics of relativistic jets. Here we report the detection of variable gamma-ray emission above 100 gigaelectron volts from the microquasar LS I +61 303. Six orbital cycles were recorded. Several detections occur at a similar orbital phase, suggesting the emission is periodic. The strongest gamma-ray emission is not observed when the two stars are closest to one another, implying a strong orbital modulation of the emission or the absorption processes.Comment: 11 pages with 4 figure

Observations of Mkn 421 with the MAGIC Telescope

The MAGIC telescope took data of very high energy gamma-ray emission from the blazar Markarian 421 (Mkn 421) between November 2004 and April 2005. We present a combined analysis of data samples recorded under different observational conditions, down to gamma-ray energies of 100 GeV. The flux was found to vary between 0.5 -- 2 Crab units (integrated above 200 GeV), considered a low state when compared to known data. Although the flux varied on a day-by-day basis, no short-term variability was observed, although there is some indication that not all nights are in an equally quiescent state. The results at higher energies were found to be consistent with previous observations. A clear correlation is observed between gamma-rays and X-rays fluxes, whereas no significant correlation between gamma-rays and optical data is seen. The spectral energy distribution between 100 GeV and 3 TeV shows a clear deviation from a power law, more clearly and at lower flux than previous observations at higher energies. The deviation persists after correcting for the effect of attenuation by the extragalactic background light, and most likely is source-inherent. There is a rather clear indication of an inverse Compton peak around 100 GeV. The spectral energy distribution of Mkn 421 can be fitted by a one-zone synchrotron self-compton model suggesting once again a leptonic origin of the very high energy gamma-ray emission from this blazar.Comment: ApJ accepted, 14 pages, 16 figures, 4 tables. updated figures 10, 11, and 12 and one referenc

Can serum hyaluronic acid replace simple non-invasive indexes to predict liver fibrosis in HIV/Hepatitis C coinfected patients?

<p>Abstract</p> <p>Background</p> <p>Hyaluronic acid (HA) serum levels correlate with the histological stages of liver fibrosis in hepatitis C virus (HCV) monoinfected patients, and HA alone has shown very good diagnostic accuracy as a non-invasive assessment of fibrosis and cirrhosis. The aim of this study was to evaluate serum HA levels as a simple non-invasive diagnostic test to predict hepatic fibrosis in HIV/HCV-coinfected patients and to compare its diagnostic performance with other previously published simple non-invasive indexes consisting of routine parameters (HGM-1, HGM-2, Forns, APRI, and FIB-4).</p> <p>Methods</p> <p>We carried out a cross-sectional study on 201 patients who all underwent liver biopsies and had not previously received interferon therapy. Liver fibrosis was determined via METAVIR score. The diagnostic accuracy of HA was assessed by area under the receiver operating characteristic curves (AUROCs).</p> <p>Results</p> <p>The distribution of liver fibrosis in our cohort was 58.2% with significant fibrosis (F≥2), 31.8% with advanced fibrosis (F≥3), and 11.4% with cirrhosis (F4). Values for the AUROC of HA levels corresponding to significant fibrosis (F≥2), advanced fibrosis (F≥3) and cirrhosis (F4) were 0.676, 0.772, and 0.863, respectively. The AUROC values for HA were similar to those for HGM-1, HGM-2, FIB-4, APRI, and Forns indexes. The best diagnostic accuracy of HA was found for the diagnosis of cirrhosis (F4): the value of HA at the low cut-off (1182 ng/mL) excluded cirrhosis (F4) with a negative predictive value of 99% and at the high cut-off (2400 ng/mL) confirmed cirrhosis (F4) with a positive predictive value of 55%. By utilizing these low and high cut-off points for cirrhosis, biopsies could have theoretically been avoided in 52.2% (111/201) of the patients.</p> <p>Conclusions</p> <p>The diagnostic accuracy of serum HA levels increases gradually with the hepatic fibrosis stage. However, HA is better than other simple non-invasive indexes using parameters easily available in routine clinical practice only for the diagnosing of cirrhosis.</p

Observation of VHE gamma-ray emission from the Active Galactic Nucleus 1ES1959+650 using the MAGIC telecope

The MAGIC Cherenkov telescope has observed very high energy (VHE) gamma-ray emission from the Active Galactic Nucleus 1ES1959+650 during six hours in September and October 2004. The observations were carried out alternated with the Crab Nebula, whose data were used as reference source for optimizing gamma/hadron separation and for flux comparison. The data analysis shows VHE gamma-ray emission of 1ES1959+650 with ~ 8 sigma significance, at a time of low activity in both optical and X-ray wavelengths. An integral flux above ~ 180 GeV of about 20% of the Crab was obtained. The light curve, sampled over 7 days, shows no significant variations. The differential energy spectrum between 180 GeV and 2 TeV can be fitted with a power law of index -2.72 +/- 0.14. The spectrum is consistent with the slightly steeper spectrum seen by HEGRA at higher energies, also during periods of low X-ray activity.Comment: 16 pages, 6 figure

Observation of Gamma Rays from the Galactic Center with the MAGIC Telescope

Recently, the Galactic Center has been reported to be a source of very high energy (VHE) gamma-rays by the VERITAS, CANGAROO and HESS experiments. The energy spectra as measured by these experiments show substantial differences. In this Letter we present MAGIC observations of the Galactic Center, resulting in the detection of a differential gamma-ray flux consistent with a steady, hard-slope power law, described as dN/(dA dt dE) = (2.9+/-0.6)*10^{-12} (E/TeV)^{-2.2+/-0.2} cm^{-2}s^{-1}TeV^{-1}. The gamma-ray source is centered at (Ra, Dec)=(17h 45m 20s, -29deg 2'. This result confirms the previous measurements by the HESS experiment and indicates a steady source of TeV gamma-rays. We briefly describe the observational technique used, the procedure implemented for the data analysis, and discuss the results in the perspective of different models proposed for the acceleration of the VHE gamma-rays.Comment: ApJL submitte

Balancing the immune response in the brain: IL-10 and its regulation

Background: The inflammatory response is critical to fight insults, such as pathogen invasion or tissue damage, but if not resolved often becomes detrimental to the host. A growing body of evidence places non-resolved inflammation at the core of various pathologies, from cancer to neurodegenerative diseases. It is therefore not surprising that the immune system has evolved several regulatory mechanisms to achieve maximum protection in the absence of pathology. Main body: The production of the anti-inflammatory cytokine interleukin (IL)-10 is one of the most important mechanisms evolved by many immune cells to counteract damage driven by excessive inflammation. Innate immune cells of the central nervous system, notably microglia, are no exception and produce IL-10 downstream of pattern recognition receptors activation. However, whereas the molecular mechanisms regulating IL-10 expression by innate and acquired immune cells of the periphery have been extensively addressed, our knowledge on the modulation of IL-10 expression by central nervous cells is much scattered. This review addresses the current understanding on the molecular mechanisms regulating IL-10 expression by innate immune cells of the brain and the implications of IL-10 modulation in neurodegenerative disorders. Conclusion: The regulation of IL-10 production by central nervous cells remains a challenging field. Answering the many remaining outstanding questions will contribute to the design of targeted approaches aiming at controlling deleterious inflammation in the brain.We acknowledge the Portuguese Foundation for Science and Technology (FCT) for providing a PhD grant to DLS (SFRH/BD/88081/2012) and a post-doctoral fellowship to SR (SFRH/BPD/72710/2010). DS, AGC and SR were funded by FEDER through the Competitiveness Factors Operational Programme (COMPETE) and National Funds through FCT under the scope of the project POCI-01-0145-FEDER007038; and by the project NORTE-01-0145-FEDER-000013, supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF). The MS lab was financed by Fundo Europeu de Desenvolvimento Regional (FEDER) funds through the COMPETE 2020—Operacional Programme for Competitiveness and Internationalisation (POCI), Portugal 2020, and by Portuguese funds through FCT in the framework of the project “Institute for Research and Innovation in Health Sciences ” (POCI-01-0145-FEDER-007274). MS is a FCT Associate Investigator. The funding body had no role in the design of the study and collection, analysis, and interpretation of the data and in writing the manuscript