Modelling Annual Scintillation Velocity Variations of FRB 20201124A

Compact radio sources exhibit scintillation, an interference pattern arising from propagation through inhomogeneous plasma, where scintillation patterns encode the relative distances and velocities of the source, scattering material, and Earth. In Main et al. 2022, we showed that the scintillation velocity of the repeating fast radio burst FRB20201124A can be measured by correlating pairs of burst spectra, and suggested that the scattering was nearby the Earth at $\sim0.4\,$kpc from the low values of the scintillation velocity and scattering timescale. In this work, we have measured the scintillation velocity at 10 epochs spanning a year, observing an annual variation which strongly implies the screen is within the Milky Way. Modelling the annual variation with a 1D anisotropic or 2D isotropic screen results in a screen distance $d_{l} = 0.24\pm0.04\,$pc or $d_{l} = 0.37\pm0.07\,$pc from Earth respectively, possibly associated with the Local Bubble or the edge of the Orion-Eridanus Superbubble. Continued monitoring, and using measurements from other telescopes particularly at times of low effective velocity will help probe changes in screen properties, and distinguish between screen models. Where scintillation of an FRB originates in its host galaxy or local environment, these techniques could be used to detect orbital motion, and probe the FRB's local ionized environment.Comment: 5 pages, 5 Figures, submitted to MNRAS Letter

Scintillation of PSR B1508+55 -- the view from a 10,000-km baseline

We report on the simultaneous Giant Metrewave Radio Telescope (GMRT) and Algonquin Radio Observatory (ARO) observations at 550-750 MHz of the scintillation of PSR B1508+55, resulting in a $\sim$10,000-km baseline. This regime of measurement lies between the shorter few 100-1000~km baselines of earlier multi-station observations and the much longer earth-space baselines. We measure a scintillation cross-correlation coefficient of $0.22$, offset from zero time lag due to a $\sim 45$~s traversal time of the scintillation pattern. The scintillation time of 135~s is $3\times$ longer, ruling out isotropic as well as strictly 1D scattering. Hence, the low cross-correlation coefficient is indicative of highly anisotropic but 2D scattering. The common scintillation detected on the baseline is confined to low delays of $\lesssim 1 \mu$s, suggesting that this correlation may not be associated with the parabolic scintillation arc detected at the GMRT. Detection of pulsed echoes and their direct imaging with the Low Frequency Array (LOFAR) by a different group enable them to measure a distance of 125~pc to the screen causing these echoes. These previous measurements, alongside our observations, lead us to propose that there are at least two scattering screens: the closer 125 pc screen causing the scintillation arc detected at GMRT, and a screen further beyond causing the scintillation detected on the GMRT-ARO baseline. We advance the hypothesis that the 125-pc screen partially resolves the speckle images on the screen beyond leading to loss of coherence in the scintillation dynamic spectrum, to explain the low cross-correlation coefficient.Comment: 10 pages, 8 figures, accepted for publication in MNRA

Alveolar macrophage- derived extracellular vesicles inhibit endosomal fusion of influenza virus

Alveolar macrophages (AMs) and epithelial cells (ECs) are the lone resident lung cells positioned to respond to pathogens at early stages of infection. Extracellular vesicles (EVs) are important vectors of paracrine signaling implicated in a range of (patho)physiologic contexts. Here we demonstrate that AMs, but not ECs, constitutively secrete paracrine activity localized to EVs which inhibits influenza infection of ECs in vitro and in vivo. AMs exposed to cigarette smoke extract lost the inhibitory activity of their secreted EVs. Influenza strains varied in their susceptibility to inhibition by AM- EVs. Only those exhibiting early endosomal escape and high pH of fusion were inhibited via a reduction in endosomal pH. By contrast, strains exhibiting later endosomal escape and lower fusion pH proved resistant to inhibition. These results extend our understanding of how resident AMs participate in host defense and have broader implications in the defense and treatment of pathogens internalized within endosomes.SynopsisExtracellular vesicles are emerging as homeostatic vectors, but poorly understood in influenza infection. Here, alveolar macrophage- derived extracellular vesicles inhibit influenza- endosome fusion in a strain- specific, and pH- dependent manner.Following initial infection of epithelial cells, the influenza virus traffics within host cell endosomes which undergo progressive acidification.Prior to gaining entry into the nucleus for its replication, influenza virus must fuse with endosome membranes- an event initiated at a strain- specific pH.Alveolar macrophages secrete extracellular vesicles which, when internalized by epithelial cells, lead to accelerated acidification of endosomes.Infection of epithelial cells by influenza strains which preferentially fuse with endosome membranes at high pH is inhibited by extracellular vesicles. Infection by influenza strains which fuse at low pH is unaffected by extracellular vesicles.Extracellular vesicles secreted from alveolar macrophages can promote acidification of endosomes in influenza virus- infected epithelial cells to inhibit viral replication.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/156477/5/embj2020105057-sup-0002-EVFigs.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156477/4/embj2020105057_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156477/3/embj2020105057.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156477/2/embj2020105057-sup-0001-Appendix.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156477/1/embj2020105057.reviewer_comments.pd

Origine sociale et comportement politique

Les conséquences politiques de la mobilité sociale intergénérationnelle sur les comportements et les attitudes politiques des individus ont fait l'objet, depuis une vingtaine d'années, d'une série de recherches en particulier aux Etats-Unis et en Angleterre. A la suite de ces travaux une conclusion majeure semble s'imposer : les « mobiles sociaux » adopteraient un comportement politique intermédiaire entre leur groupe d'origine et leur groupe d'arrivée. Dans cette recherche, qui se fonde sur l'analyse d'un échantillon représentatif de cadres moyens et supérieurs, l'origine sociale paraît effectivement déterminer pour partie les comportements et attitudes politiques des individus appartenant aux couches moyennes salariées. Toutefois, une étude plus précise de ce mécanisme montre que l'effet de l'origine sociale sur le comportement et les attitudes politiques n'est pas seulement fonction de la distance entre la position sociale du père et celle du fils mais se diversifie également selon la nature et les conditions du trajet social effectué par l'individu.The political consequences of intergenerational social mobility on individuals' political attitudes and behavior have been studied in a series of inquiries over the past twenty years, especially in the United States and England. As a result of this work, it seems that one major conclusion may be drawn: the "socially mobile" seem to adopt a political behavior which is intermediate to that of the group from which they started out and that into which they are arriving. In this study based on a representative sample of middle — and upper — level executives, social origin indeed seems to be in part a determining factor in the political behavior and attitudes of individuals belonging to the middle range of the wage scale. However, a closer study of this mechanism shows that the effect of social origin upon political behavior and attitudes is not only a function of the distance between the father's and the son's social positions, but also differs according to the nature and conditions of the individual's social ascension

TiEMPO: Open-source time-dependent end-to-end model for simulating ground-based submillimeter astronomical observations

The next technological breakthrough in millimeter-submillimeter astronomy is 3D imaging spectrometry with wide instantaneous spectral bandwidths and wide fields of view. The total optimization of the focal-plane instrument, the telescope, the observing strategy, and the signal-processing software must enable efficient removal of foreground emission from the Earth's atmosphere, which is time-dependent and highly nonlinear in frequency. Here we present TiEMPO: Time-Dependent End-to-End Model for Post-process Optimization of the DESHIMA Spectrometer. TiEMPO utilizes a dynamical model of the atmosphere and parametrized models of the astronomical source, the telescope, the instrument, and the detector. The output of TiEMPO is a time-stream of sky brightness temperature and detected power, which can be analyzed by standard signal-processing software. We first compare TiEMPO simulations with an on-sky measurement by the wideband DESHIMA spectrometer and find good agreement in the noise power spectral density and sensitivity. We then use TiEMPO to simulate the detection of a line emission spectrum of a high-redshift galaxy using the DESHIMA 2.0 spectrometer in development. The TiEMPO model is open source. Its modular and parametrized design enables users to adapt it to design and optimize the end-to-end performance of spectroscopic and photometric instruments on existing and future telescopes.Comment: Presented at SPIE Astronomical Telescopes + Instrumentation 2020. Full published paper, poster and video available at https://doi.org/10.1117/12.2561014 Open-source Python package of TiEMPO: https://pypi.org/project/tiempo-deshima/ Open-source code of TiEMPO: https://zenodo.org/record/4279086#.X_jAsdhKg2

Enterovirus D68 and other enterovirus serotypes identified in South African patients with severe acute respiratory illness, 2009-2011

BACKGROUND : Human enteroviruses (EV) have been associated with severe acute respiratory illness (SARI) in South Africa. OBJECTIVES : We aimed to describe the molecular epidemiology of EV serotypes among patients hospitalized with SARI during 2009-2011. PATIENTS/METHODS : Study samples from patients were tested for the presence of enterovirus using a polymerase chain reaction assay. RESULTS : 8.2% (842/10 260) of SARI cases tested positive for enterovirus; 16% (7/45) were species EV-A, 44% (20/45) EV-B, 18% (8/45) EV-C and 22% (10/45) EV-D. Seventeen different EV serotypes were identified within EV-A to EV-D, of which EV-D68 (22%; 10/45) and Echovirus 3 (11%; 5/45) were the most prevalent. CONCLUSIONS : EV-D68 should be monitored in South Africa to assess the emergence of highly pathogenic strains.The United States Centers for Disease Control and Prevention, Atlanta, Georgia, USA (co-operative agreement number: 5U51IP000155).http://www.wileyonlinelibrary.com/journal/irvhttp://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1750-2659am2018Medical Virolog

The role of influenza, RSV and other common respiratory viruses in severe acute respiratory infections and influenza-like illness in a population with a high HIV sero-prevalence, South Africa, 2012-2015

BACKGROUND : Viruses detected in patients with acute respiratory infections may be the cause of illness or colonizers. METHODS : We compared the prevalence of 10 common respiratory viruses (influenza A and B viruses, parainfluenza virus 1, 2, and 3; respiratory syncytial virus (RSV); adenovirus, rhinovirus, human metapneumovirus (hMPV) and enterovirus) in patients hospitalized with severe acute respiratory illness (SARI), outpatients with influenza-like illness (ILI), and control subjects who did not report any febrile, respiratory or gastrointestinal illness during 2012-2015 in South Africa. We estimated the attributable fraction (AF) and the detection rate attributable to illness for each of the different respiratory viruses. RESULTS : We enrolled 1959 SARI, 3784 ILI and 1793 controls. Influenza virus (AF: 86.3%; 95%CI: 77.7%-91.6%), hMPV (AF: 85.6%%; 95%CI: 72.0%-92.6%), and RSV (AF: 83.7%; 95%CI: 77.5%-88.2%) infections were highly associated with severe disease, while rhinovirus (AF: 46.9%; 95%CI: 37.6%-56.5%) and adenovirus (AF: 36.4%; 95%CI: 20.6%-49.0%) were only moderately associated. The estimated detection rate associated with severe disease was: 20.2% for rhinovirus, 16.7% for RSV, 7.0% for adenovirus, 4.9% for influenza virus and 3.8% for hMPV. Similar patterns were observed for patients with ILI. CONCLUSIONS : Influenza, RSV and hMPV can be considered likely pathogens if detected in patients with ILI and SARI while rhinovirus and adenovirus were commonly identified also among controls suggesting that they may cause only a proportion of clinical disease observed in positive patients. Nonetheless, given their high estimated detection rate attributable to illness, they may be important contributors to disease.Co-operative agreement 5U51/IP000155 with the Centers for Disease Control and Prevention, Atlanta, Georgia, USA.http://www.elsevier.com/locate/jcv2017-02-28hb2016Medical Virolog

Simultaneous and panchromatic observations of the fast radio burst FRB 20180916B

Aims. Fast radio bursts are bright radio transients whose origins are not yet understood. The search for a multi-wavelength counterpart of those events can set a tight constraint on the emission mechanism and the progenitor source.Methods. We conducted a multi-wavelength observational campaign on FRB 20180916B between October 2020 and August 2021 over eight activity cycles of the source. Observations were carried out in the radio band by the SRT both at 336 and 1547 MHz and the uGMRT at 400 MHz. Simultaneous observations were conducted by the optical telescopes Asiago (Galileo and Copernico), CMO SAI MSU, CAHA 2.2 m, RTT-150 and TNG, and X/?-ray detectors on board the AGILE, Insight-HXMT, INTEGRAL, and Swift satellites.Results. We present the detection of 14 new radio bursts detected with the SRT at 336 MHz and seven new bursts with the uGMRT from this source. We provide the deepest prompt upper limits in the optical band for FRB 20180916B to date. In fact, the TNG/SiFAP2 observation simultaneous to a burst detection by uGMRT gives an upper limit E-optical/E-radio < 1.3 x 10(2). Another burst detected by the SRT at 336 MHz was also co-observed by Insight-HXMT. The non-detection in the X-rays yields an upper limit (1 - 30 keV band) of EX - ray/E-radio in the range of (0.9 - 1.3) x 10(7), depending on the model that is considered for the X-ray emission

Simultaneous and panchromatic observations of the Fast Radio Burst FRB 20180916B

Aims. Fast Radio Bursts are bright radio transients whose origin has not yet explained. The search for a multi-wavelength counterpart of those events can put a tight constrain on the emission mechanism and the progenitor source. Methods. We conducted a multi-wavelength observational campaign on FRB 20180916B between October 2020 and August 2021 during eight activity cycles of the source. Observations were led in the radio band by the SRT both at 336 MHz and 1547 MHz and the uGMRT at 400 MHz. Simultaneous observations have been conducted by the optical telescopes Asiago (Galileo and Copernico), CMO SAI MSU, CAHA 2.2m, RTT-150 and TNG, and X/Gamma-ray detectors on board the AGILE, Insight-HXMT, INTEGRAL and Swift satellites. Results. We present the detection of 14 new bursts detected with the SRT at 336 MHz and seven new bursts with the uGMRT from this source. We provide the deepest prompt upper limits in the optical band fro FRB 20180916B to date. In fact, the TNG/SiFAP2 observation simultaneous to a burst detection by uGMRT gives an upper limit E_optical / E_radio < 1.3 x 10^2. Another burst detected by the SRT at 336 MHz was also co-observed by Insight-HMXT. The non-detection in the X-rays yields an upper limit (1-30 keV band) of E_X-ray / E_radio in the range of (0.9-1.3) x 10^7, depending on which model is considered for the X-ray emission.Comment: A&A accepte

Mortality in children aged <5 years with severe acute respiratory illness in a high HIV-prevalence urban and rural areas of South Africa, 2009–2013

BACKGROUND: Severe acute respiratory illness (SARI) is an important cause of mortality in young children, especially in children living with HIV infection. Disparities in SARI death in children aged <5 years exist in urban and rural areas. OBJECTIVE: To compare the factors associated with in-hospital death among children aged <5 years hospitalized with SARI in an urban vs. a rural setting in South Africa from 2009–2013. METHODS: Data were collected from hospitalized children with SARI in one urban and two rural sentinel surveillance hospitals. Nasopharyngeal aspirates were tested for ten respiratory viruses and blood for pneumococcal DNA using polymerase chain reaction. We used multivariable logistic regression to identify patient and clinical characteristics associated with in-hospital death. RESULTS: From 2009 through 2013, 5,297 children aged <5 years with SARI-associated hospital admission were enrolled; 3,811 (72%) in the urban and 1,486 (28%) in the rural hospitals. In-hospital case-fatality proportion (CFP) was higher in the rural hospitals (6.9%) than the urban hospital (1.3%, p<0.001), and among HIV-infected than the HIV-uninfected children (9.6% vs. 1.6%, p<0.001). In the urban hospital, HIV infection (odds ratio (OR):11.4, 95% confidence interval (CI):5.4–24.1) and presence of any other underlying illness (OR: 3.0, 95% CI: 1.0–9.2) were the only factors independently associated with death. In the rural hospitals, HIV infection (OR: 4.1, 95% CI: 2.3–7.1) and age <1 year (OR: 3.7, 95% CI: 1.9– 7.2) were independently associated with death, whereas duration of hospitalization ≥ 5 days (OR: 0.5, 95% CI: 0.3–0.8) and any respiratory virus detection (OR: 0.4, 95% CI: 0.3–0.8) were negatively associated with death. CONCLUSION: We found that the case-fatality proportion was substantially higher among children admitted to rural hospitals and HIV infected children with SARI in South Africa. While efforts to prevent and treat HIV infections in children may reduce SARI deaths, further efforts to address health care inequality in rural populations are needed.http://www.plosone.orgpm2022Medical Virolog