The WEBT BL Lacertae Campaign 2001 and its extension : Optical light curves and colour analysis 1994–2002

BL Lacertae has been the target of four observing campaigns by the Whole Earth Blazar Telescope (WEBT) collaboration. In this paper we present UBVRI light curves obtained by theWEBT from 1994 to 2002, including the last, extended BL Lac 2001 campaign. A total of about 7500 optical observations performed by 31 telescopes from Japan to Mexico have been collected, to be added to the ∼15 600 observations of the BL Lac Campaign 2000. All these data allow one to follow the source optical emission behaviour with unprecedented detail. The analysis of the colour indices reveals that the flux variability can be interpreted in terms of two components: longer-term variations occurring on a fewday time scale appear as mildly-chromatic events, while a strong bluer-when-brighter chromatism characterizes very fast (intraday) flares. By decoupling the two components, we quantify the degree of chromatism inferring that longer-term flux changes imply moving along a ∼0.1 bluerwhen- brighter slope in the B − R versus R plane; a steeper slope of ∼0.4 would distinguish the shorter-term variations. This means that, when considering the long-term trend, the B-band flux level is related to the R-band one according to a power law of index ∼1.1. Doppler factor variations on a “convex” spectrum could be the mechanism accounting for both the long-term variations and their slight chromatism.Reig Torres, Pablo, [email protected]

Multi-frequency monitoring of γ-ray loud blazars I. Light curves and spectral energy distributions

Context: Being dominated by non-thermal emission from aligned relativistic jets, blazars allow us to elucidate the physics of extragalactic jets, and, ltimately, how the energy is extracted from the central black hole in radio-loud active galactic nuclei. Aims: Crucial information is provided by broad-band spectral energy distributions (SEDs), their trends with luminosity and correlated multi-frequency variability. With this study we plan to obtain a database of contemporaneous radio-to-optical spectra of a sample of blazars, which are and will be observed by current and future high-energy satellites. Methods: Since December 2004 we are performing a monthly multi-frequency radio monitoring of a sample of 35 blazars at the antennas in Medicina and Noto. Contemporaneous near-IR and optical observations for all our observing epochs are organised. Results: Until June 2006 about 4000 radio measurements and 5500 near-IR and optical measurements were obtained. Most of the sources show significant variability in all observing bands. Here we present the multi-frequency data acquired during the first eighteen months of the project, and construct the SEDs for the best-sampled sources

Multifrequency variability of the blazar AO 0235+164 the WEBT campaign in 2004-2005 and long-term SED analysis

A huge multiwavelength campaign targeting the blazar AO 0235+164 was organized by the Whole Earth Blazar Telescope (WEBT) in 2003-2005 to study the variability properties of the source. Monitoring observations were carried out at cm and mm wavelengths, and in the near-IR and optical bands, while three pointings by the XMM-Newton satellite provided information on the X-ray and UV emission. We present the data acquired during the second observing season, 2004-2005, by 27 radio-to-optical telescopes. They reveal an increased near-IR and optical activity with respect to the previous season. Increased variability is also found at the higher radio frequencies, down to 15 GHz, but not at the lower ones. The radio (and optical) outburst predicted to peak around February-March 2004 on the basis of the previously observed 5-6 yr quasi-periodicity did not occur. The analysis of the optical light curves reveals now a longer characteristic time scale of 8 yr, which is also present in the radio data. The spectral energy distributions corresponding to the XMM-Newton observations performed during the WEBT campaign are compared with those pertaining to previous pointings of X-ray satellites. Bright, soft X-ray spectra can be described in terms of an extra component, which appears also when the source is faint through a hard UV spectrum and a curvature of the X-ray spectrum. Finally, there might be a correlation between the X-ray and optical bright states with a long time delay of about 5 yr, which would require a geometrical interpretation

The structure and emission model of the relativistic jet in the quasar 3C279 inferred from radio to high-energy γ-ray observations in 2008-2010

We present time-resolved broadband observations of the quasar 3C279 obtained from multi-wavelength campaigns conducted during the first two years of the Fermi Gamma-ray Space Telescope mission. While investigating the previously reported γ-ray/optical flare accompanied by a change in optical polarization, we found that the optical emission appears to be delayed with respect to the γ-ray emission by about 10days. X-ray observations reveal a pair of "isolated" flares separated by 90 days, with only weak γ-ray/optical counterparts. The spectral structure measured by Spitzer reveals a synchrotron component peaking in the mid-infrared band with a sharp break at the far-infrared band during the γ-ray flare, while the peak appears in the millimeter (mm)/submillimeter (sub-mm) band in the low state. Selected spectral energy distributions are fitted with leptonic models including Comptonization of external radiation produced in a dusty torus or the broad-line region. Adopting the interpretation of the polarization swing involving propagation of the emitting region along a curved trajectory, we can explain the evolution of the broadband spectra during the γ-ray flaring event by a shift of its location from 1pc to 4pc from the central black hole. On the other hand, if the γ-ray flare is generated instead at sub-pc distance from the central black hole, the far-infrared break can be explained by synchrotron self-absorption. We also model the low spectral state, dominated by the mm/sub-mm peaking synchrotron component, and suggest that the corresponding inverse-Compton component explains the steady X-ray emission. © 2012. The American Astronomical Society. All rights reserved.

Multi-wavelength observations of blazar AO 0235+164 in the 2008-2009 flaring state

The blazar AO 0235+164 (z = 0.94) has been one of the most active objects observed by Fermi Large Area Telescope (LAT) since its launch in Summer 2008. In addition to the continuous coverage by Fermi, contemporaneous observations were carried out from the radio to γ-ray bands between 2008 September and 2009 February. In this paper, we summarize the rich multi-wavelength data collected during the campaign (including F-GAMMA, GASP-WEBT, Kanata, OVRO, RXTE, SMARTS, Swift, and other instruments), examine the cross-correlation between the light curves measured in the different energy bands, and interpret the resulting spectral energy distributions in the context of well-known blazar emission models. We find that the γ-ray activity is well correlated with a series of near-IR/optical flares, accompanied by an increase in the optical polarization degree. On the other hand, the X-ray light curve shows a distinct 20 day high state of unusually soft spectrum, which does not match the extrapolation of the optical/UV synchrotron spectrum. We tentatively interpret this feature as the bulk Compton emission by cold electrons contained in the jet, which requires an accretion disk corona with an effective covering factor of 19% at a distance of 100 R g. We model the broadband spectra with a leptonic model with external radiation dominated by the infrared emission from the dusty torus. © 2012. The American Astronomical Society. All rights reserved

Insights into the high-energy γ-ray emission of Markarian 501 from extensive multifrequency observations in the Fermi era

We report on the γ-ray activity of the blazar Mrk 501 during the first 480 days of Fermi operation. We find that the average Large Area Telescope (LAT) γ-ray spectrum of Mrk 501 can be well described by a single power-law function with a photon index of 1.78 ± 0.03. While we observe relatively mild flux variations with the Fermi-LAT (within less than a factor of two), we detect remarkable spectral variability where the hardest observed spectral index within the LAT energy range is 1.52 ± 0.14, and the softest one is 2.51 ± 0.20. These unexpected spectral changes do not correlate with the measured flux variations above 0.3 GeV. In this paper, we also present the first results from the 4.5 month long multifrequency campaign (2009 March 15-August 1) on Mrk 501, which included the Very Long Baseline Array (VLBA), Swift, RXTE, MAGIC, and VERITAS, the F-GAMMA, GASP-WEBT, and other collaborations and instruments which provided excellent temporal and energy coverage of the source throughout the entire campaign. The extensive radio to TeV data set from this campaign provides us with the most detailed spectral energy distribution yet collected for this source during its relatively low activity. The average spectral energy distribution of Mrk 501 is well described by the standard one-zone synchrotron self-Compton (SSC) model. In the framework of this model, we find that the dominant emission region is characterized by a size ≲0.1 pc (comparable within a factor of few to the size of the partially resolved VLBA core at 15-43 GHz), and that the total jet power (≃1044 erg s-1) constitutes only a small fraction (∼10-3) of the Eddington luminosity. The energy distribution of the freshly accelerated radiating electrons required to fit the time-averaged data has a broken power-law form in the energy range 0.3 GeV-10 TeV, with spectral indices 2.2 and 2.7 below and above the break energy of 20 GeV. We argue that such a form is consistent with a scenario in which the bulk of the energy dissipation within the dominant emission zone of Mrk 501 is due to relativistic, proton-mediated shocks. We find that the ultrarelativistic electrons and mildly relativistic protons within the blazar zone, if comparable in number, are in approximate energy equipartition, with their energy dominating the jet magnetic field energy by about two orders of magnitude. © 2011. The American Astronomical Society

A comparative study of the effectiveness of regimens for the treatment of calicivirus infection in cats-a comparative study

© 2020, Veterinary Practitioner. All rights reserved. Feline calicivirus (FCV) is a frequent pathogen in cats. In most cases, it causes mild, self-limited acute diseases of the oral cavity and the upper respiratory tract or chronic diseases of the oral cavity. In recent years, virulent strains of FCV have been registered that cause severe, systemic diseases in cats, with a high mortality rate, and are not preventable with modern vaccines. This study aims to evaluate the effectiveness of various methods for the treatment of calicivirus infection in cats. The research was conducted on 30 stray cats with calicivirus infection. The animals were divided into three groups. We developed several treatment regimens based on antibacterial drugs (clindamycin and amoxicillin), as well as immune modulators, such as Phosprenyl and Maxidin. Additionally, globulin Globfel-4 was administered to the animals of the third group. Clinical signs and general health condition were recorded daily during 14 days, and again on days 20 and 30. Feline calicivirus presence was tested by quantitative polymerase chain reaction (qPCR) on days 0, 10, and 30. It was found that the inclusion of a specific globulin in the complex therapy, namely Globfel-4, allows reducing the convalescence period and eliminating the pathogen

Changes in the functionality of tear film and autorefractometry reading after instillations of artificial tear products of different viscosity

V.V. Brzheskiy1, E.L. Efimova1, M.A. Kopylova1, P.V. Kocharina1, A.A. Primak1, V.P. Nikolaenko2 1St. Petersburg State Pediatric Medical University, Saint-Petersburg, Russian Federation 2St. Petersburg State University, Saint-Petersburg, Russian Federation Aim: to study the changes in the critical parameters of tear film stability and autorefractometry in patients with mild dry eye syndrome (DES) after instilling artificial tear products of different viscosity. Patients and Methods: thirty patients aged 23–70 with mild bilateral DES were examined using the Visionix VX120+Dry Eye multi-diagnostic unit equipped with the TF-Scan to fix and assess tear film stability and tear breakup time (TBUT). The critical refraction and tear film parameters were evaluated by keratometry, corneal topography, TBUT, and tear meniscus height measurements. Next, an artificial tear product was instilled, i.e., group 1 (14 patients, 28 eyes) received a 0.15% sodium hyaluronate-based preparation, and group 2 (16 patients, 32 eyes) received a 0.4% sodium hyaluronate-based preparation. The examination was repeated after 30 sec and 5 min. Controls were seven healthy individuals (14 eyes). Results: in DES, breaks in the tear film appeared earlier and affected greater corneal surface area. A "Destabilized tear film area" parameter of the Visionix VX120+Dry Eye contributed significantly to the knowledge of tear film functionality, thereby empowering the diagnostic armamentarium in DES. As early as 30 sec after instillation of both artificial tear preparations, breakup-free time tended to increase, while the area of tear film destabilization tended to reduce. After 5 min, this trend continued to increase, particularly after instilling 0.15% sodium hyaluronate-based preparation. At the same time, changes in keratometry readings (i.e., sphere and cylinder) and astigmatism axis orientation were reported. Corneal refractive power (more in the flattest axis) increased, in particular, after the instillations of 0.15% hyaluronic acid. The range of changes was 0.00–0.75 D for the sphere power, 0.00–0.50 D for the cylinder power, and 0–69 degrees f or astigmatism axis orientation. Conclusions: our findings with the Visionix VX120+Dry Eye multi-diagnostic unit demonstrate a significant variation of autorefractometry readings in DES depending on the extent of ocular surface hydration. These phenomena raise questions about the accuracy of autorefractometry readings. Therefore, autorefractometry should be performed after normalizing tear film volume and stability. Keywords: dry eye syndrome, Visionix®, autorefractometry, tearscopy, the effect of artificial tears on results. For citation: Brzheskiy V.V., Efimova E.L., Kopylova M.A. et al. Changes in the functionality of tear film and autorefractometry reading after instillations of artificial tear products of different viscosity. Russian Journal of Clinical Ophthalmology. 2021;21(4):200–204 (in Russ.). DOI: 10.32364/2311-7729-2021-21-4-200-204. <br

Bacillus pumilus ribonuclease rescues mice infected by double-stranded RNA-containing reovirus serotype 1

© 2020 Elsevier B.V. Reoviruses (respiratory enteric orphan viruses) are nonenveloped viruses with segmented dsRNA genome. Viruses in the family Reoviridae are quite stable in the environment. Recently, they have been identified with various pathologies and physiologic dysfunctions in a wide range of organs and tissues, including the hepatobiliary system, the myocardium, lungs, and endocrine tissues. Although most cases of reovirus infection are mild or subclinical diseases, the prevention measures are currently needed, especially for young children suffering from dehydrating gastroenteritis. To inhibit viral replication, different RNases targeting viral RNA are proposed. Here, we first have shown that RNase from Bacillus pumilus (binase) acts as an antiviral agent at the level of the whole animal organism infected by Mammalian orthoreovirus 1 strain Lang (TL1). The results obtained on the mice model infected with 10 LD50 and 20 LD50 doses of reovirus indicate the restoration of mice physiological parameters under binase treatment at the dose of 50 μg/mouse. Thus, our research supports the relevance of binase as a promising antiviral agent that affects viral RNA

Molecular detection of Coxiella burnetii and Borrelia burgdorferi in ticks infesting goats in North-Eastern states of India

© 2020 Informa UK Limited, trading as Taylor & Francis Group. Coxiella burnetii: and Borrelia burgdorferi sensu lato are intracellular bacteria of great zoonotic importance. To detect these two pathogensin ticks as well as in blood samples, a nested PCR and conventional PCR was used. A total of 525 ticks were collected randomly from infected goats. Blood samples were also collected from tick-infested goats. Both samples were assessed for the presence of these organisms using Polymerase chain reaction (PCR) assays targeting a fragment of 16S rRNA, superoxide dismutase (SOD) of C. burnetii and ospA gene of B. burgdorferi s.l. Sequence analysis of the amplified fragment was used to confirm PCR findings. The PCR products were purified, cloned and custom sequenced. A few blood samples were found positive for both C. burnetii and B. Burgdorferi sensu lato. A total of 12 isolates of the 16S rRNA gene fragment and one isolate of the SOD gene fragment of C. burnetii were obtained. The sequences were aligned and a phylogenetic tree was made with other published C. burnetii sequences. Our finding indicated that ticks were infesting goats as well as blood samples harbour C. burnetii and B. burgdorferi sensu lato providing possible zoonotic transmission of these bacteria from animals to humans through ticks