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

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

CCL3 Promotes Germinal Center B Cells Sampling by Follicular Regulatory T Cells in Murine Lymph Nodes

Previous studies and our findings suggest upregulated expression of proinflammatory chemokines CCL3/4 in germinal center (GC) centrocytes. However, the role of CCL3/4 for centrocyte interactions with follicular T cells and regulation of humoral immunity is poorly understood. We found that CCL3 promotes chemotaxis of Tfr cells ex vivo. Two-photon imaging revealed that B cells-intrinsic production of CCL3 promotes their probing by follicular regulatory T cells (Tfr) within GCs of murine lymph nodes. Overall this study suggests that CCL3 facilitates direct interactions of foreign antigen-specific GC B cells and their negative regulation with Tfr cells in vivo

The CMS Outer Hadron Calorimeter

The CMS hadron calorimeter is a sampling calorimeter with brass absorber and plastic scintillator tiles with wavelength shifting fibres for carrying the light to the readout device. The barrel hadron calorimeter is complemented with a outer calorimeter to ensure high energy shower containment in CMS and thus working as a tail catcher. Fabrication, testing and calibrations of the outer hadron calorimeter are carried out keeping in mind its importance in the energy measurement of jets in view of linearity and resolution. It will provide a net improvement in missing \et measurements at LHC energies. The outer hadron calorimeter has a very good signal to background ratio even for a minimum ionising particle and can hence be used in coincidence with the Resistive Plate Chambers of the CMS detector for the muon trigger

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

Design, Performance, and Calibration of the CMS Hadron-Outer Calorimeter

The CMS hadron calorimeter is a sampling calorimeter with brass absorber and plastic scintillator tiles with wavelength shifting fibres for carrying the light to the readout device. The barrel hadron calorimeter is complemented with an outer calorimeter to ensure high energy shower containment in the calorimeter. Fabrication, testing and calibration of the outer hadron calorimeter are carried out keeping in mind its importance in the energy measurement of jets in view of linearity and resolution. It will provide a net improvement in missing \et measurements at LHC energies. The outer hadron calorimeter will also be used for the muon trigger in coincidence with other muon chambers in CMS

Effects of betaine on enumeration of airborne bacteria.

The osmoprotectant betaine was incorporated into collection fluid and enumeration medium to determine its effects on the colony-forming abilities of airborne bacteria, which were collected from three separate locations: a wastewater treatment plant, the roof of a laboratory building, and an unobstructed farmland. At all locations, addition of 2 to 5 mM betaine caused a significant increase (from 21.6 to 61.3%) in colonial outgrowth, compared with the growth rate of controls without betaine. The presence of betaine in both the collection fluid and the enumeration medium had an additive effect on the colony-forming ability of airborne bacteria compared with the presence of betaine in either one alone. The effect of various betaine concentrations on the enumeration of aerosolized Pseudomonas syringae was determined. Betaine showed a threshold for maximum effect at a concentration of 2 to 5 mM. At higher concentrations (10 to 20 mM), the effects of betaine were negligible or possibly inhibitory. The significance of these results with respect to the development of protocols for monitoring airborne microorganisms, including genetically engineered microorganisms, is discussed