Room temperature ammonia gas sensing characteristics of Co3O4

Room temperature ammonia gas-sensing characteristics of Co3O4 pellet sensor are reported in this paper. For this purpose, Co3O4 powder is prepared by a route of simple precipitation + heating at 800° C/2 hr. The as-prepared powder is characterized by using X-ray diffraction and scanning electron microscopy. The ammonia gas-sensing properties of Co3O4 pellets made at various loads of 3, 5, 7 & 9 ton and at constant time 4 min. are measured using home-built static gas sensing system. The characterization studies revealed that the cobalt oxide particles formed are cubic spinel Co3O4, highly pure and spherical in shape. The particle size distribution is found to be nearly uniform with average particle size ~ 1 μm. The ammonia gas sensing properties of Co3O4 pellet sensor are found to be good. The highest sensitivities – S.F. 175 and 358 are found at ~ 25 ppm and 250 ppm concentrations of ammonia gas respectively for the Co3O4 pellet sensor made at the load 3 ton. Further, an admirable repeatability and reversibility in the ammonia gas sensing characteristics are observed for all the Co3O4 pellet sensors. The average response time of 4.0 min. and recovery time of 3.0 min. are obtained for all the Co3O4 pellet sensors. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2785

Search for Gravitational Waves Associated with Gamma-Ray Bursts Detected by Fermi and Swift during the LIGO-Virgo Run O3b

We search for gravitational-wave signals associated with gamma-ray bursts (GRBs) detected by the Fermi and Swift satellites during the second half of the third observing run of Advanced LIGO and Advanced Virgo (2019 November 1 15:00 UTC-2020 March 27 17:00 UTC). We conduct two independent searches: A generic gravitational-wave transients search to analyze 86 GRBs and an analysis to target binary mergers with at least one neutron star as short GRB progenitors for 17 events. We find no significant evidence for gravitational-wave signals associated with any of these GRBs. A weighted binomial test of the combined results finds no evidence for subthreshold gravitational-wave signals associated with this GRB ensemble either. We use several source types and signal morphologies during the searches, resulting in lower bounds on the estimated distance to each GRB. Finally, we constrain the population of low-luminosity short GRBs using results from the first to the third observing runs of Advanced LIGO and Advanced Virgo. The resulting population is in accordance with the local binary neutron star merger rate. © 2022. The Author(s). Published by the American Astronomical Society

Narrowband Searches for Continuous and Long-duration Transient Gravitational Waves from Known Pulsars in the LIGO-Virgo Third Observing Run

Isolated neutron stars that are asymmetric with respect to their spin axis are possible sources of detectable continuous gravitational waves. This paper presents a fully coherent search for such signals from eighteen pulsars in data from LIGO and Virgo's third observing run (O3). For known pulsars, efficient and sensitive matched-filter searches can be carried out if one assumes the gravitational radiation is phase-locked to the electromagnetic emission. In the search presented here, we relax this assumption and allow both the frequency and the time derivative of the frequency of the gravitational waves to vary in a small range around those inferred from electromagnetic observations. We find no evidence for continuous gravitational waves, and set upper limits on the strain amplitude for each target. These limits are more constraining for seven of the targets than the spin-down limit defined by ascribing all rotational energy loss to gravitational radiation. In an additional search, we look in O3 data for long-duration (hours-months) transient gravitational waves in the aftermath of pulsar glitches for six targets with a total of nine glitches. We report two marginal outliers from this search, but find no clear evidence for such emission either. The resulting duration-dependent strain upper limits do not surpass indirect energy constraints for any of these targets. © 2022. The Author(s). Published by the American Astronomical Society

GW190814: gravitational waves from the coalescence of a 23 solar mass black hole with a 2.6 solar mass compact object

We report the observation of a compact binary coalescence involving a 22.2–24.3 Me black hole and a compact object with a mass of 2.50–2.67 Me (all measurements quoted at the 90% credible level). The gravitational-wave signal, GW190814, was observed during LIGO’s and Virgo’s third observing run on 2019 August 14 at 21:10:39 UTC and has a signal-to-noise ratio of 25 in the three-detector network. The source was localized to 18.5 deg2 at a distance of - + 241 45 41 Mpc; no electromagnetic counterpart has been confirmed to date. The source has the most unequal mass ratio yet measured with gravitational waves, - + 0.112 0.009 0.008, and its secondary component is either the lightest black hole or the heaviest neutron star ever discovered in a double compact-object system. The dimensionless spin of the primary black hole is tightly constrained to �0.07. Tests of general relativity reveal no measurable deviations from the theory, and its prediction of higher-multipole emission is confirmed at high confidence. We estimate a merger rate density of 1–23 Gpc−3 yr−1 for the new class of binary coalescence sources that GW190814 represents. Astrophysical models predict that binaries with mass ratios similar to this event can form through several channels, but are unlikely to have formed in globular clusters. However, the combination of mass ratio, component masses, and the inferred merger rate for this event challenges all current models of the formation and mass distribution of compact-object binaries

Open data from the third observing run of LIGO, Virgo, KAGRA, and GEO

The global network of gravitational-wave observatories now includes five detectors, namely LIGO Hanford, LIGO Livingston, Virgo, KAGRA, and GEO 600. These detectors collected data during their third observing run, O3, composed of three phases: O3a starting in 2019 April and lasting six months, O3b starting in 2019 November and lasting five months, and O3GK starting in 2020 April and lasting two weeks. In this paper we describe these data and various other science products that can be freely accessed through the Gravitational Wave Open Science Center at https://gwosc.org. The main data set, consisting of the gravitational-wave strain time series that contains the astrophysical signals, is released together with supporting data useful for their analysis and documentation, tutorials, as well as analysis software packages

Search for gravitational-wave transients associated with magnetar bursts in advanced LIGO and advanced Virgo data from the third observing run

Gravitational waves are expected to be produced from neutron star oscillations associated with magnetar giant f lares and short bursts. We present the results of a search for short-duration (milliseconds to seconds) and longduration (∼100 s) transient gravitational waves from 13 magnetar short bursts observed during Advanced LIGO, Advanced Virgo, and KAGRA’s third observation run. These 13 bursts come from two magnetars, SGR1935 +2154 and SwiftJ1818.0−1607. We also include three other electromagnetic burst events detected by FermiGBM which were identified as likely coming from one or more magnetars, but they have no association with a known magnetar. No magnetar giant flares were detected during the analysis period. We find no evidence of gravitational waves associated with any of these 16 bursts. We place upper limits on the rms of the integrated incident gravitational-wave strain that reach 3.6 × 10−²³ Hz at 100 Hz for the short-duration search and 1.1 ×10−²² Hz at 450 Hz for the long-duration search. For a ringdown signal at 1590 Hz targeted by the short-duration search the limit is set to 2.3 × 10−²² Hz. Using the estimated distance to each magnetar, we derive upper limits upper limits on the emitted gravitational-wave energy of 1.5 × 1044 erg (1.0 × 1044 erg) for SGR 1935+2154 and 9.4 × 10^43 erg (1.3 × 1044 erg) for Swift J1818.0−1607, for the short-duration (long-duration) search. Assuming isotropic emission of electromagnetic radiation of the burst fluences, we constrain the ratio of gravitational-wave energy to electromagnetic energy for bursts from SGR 1935+2154 with the available fluence information. The lowest of these ratios is 4.5 × 103

Constraints on the cosmic expansion history from GWTC–3

We use 47 gravitational wave sources from the Third LIGO–Virgo–Kamioka Gravitational Wave Detector Gravitational Wave Transient Catalog (GWTC–3) to estimate the Hubble parameter H(z), including its current value, the Hubble constant H0. Each gravitational wave (GW) signal provides the luminosity distance to the source, and we estimate the corresponding redshift using two methods: the redshifted masses and a galaxy catalog. Using the binary black hole (BBH) redshifted masses, we simultaneously infer the source mass distribution and H(z). The source mass distribution displays a peak around 34 M⊙, followed by a drop-off. Assuming this mass scale does not evolve with the redshift results in a H(z) measurement, yielding ${H}_{0}={68}_{-8}^{+12}\,\mathrm{km}\ \,\ {{\rm{s}}}^{-1}\,{\mathrm{Mpc}}^{-1}$ (68% credible interval) when combined with the H0 measurement from GW170817 and its electromagnetic counterpart. This represents an improvement of 17% with respect to the H0 estimate from GWTC–1. The second method associates each GW event with its probable host galaxy in the catalog GLADE+, statistically marginalizing over the redshifts of each event's potential hosts. Assuming a fixed BBH population, we estimate a value of ${H}_{0}={68}_{-6}^{+8}\,\mathrm{km}\ \,\ {{\rm{s}}}^{-1}\,{\mathrm{Mpc}}^{-1}$ with the galaxy catalog method, an improvement of 42% with respect to our GWTC–1 result and 20% with respect to recent H0 studies using GWTC–2 events. However, we show that this result is strongly impacted by assumptions about the BBH source mass distribution; the only event which is not strongly impacted by such assumptions (and is thus informative about H0) is the well-localized event GW190814

A joint Fermi-GBM and Swift-BAT analysis of gravitational-wave candidates from the third gravitational-wave observing run

We present Fermi Gamma-ray Burst Monitor (Fermi-GBM) and Swift Burst Alert Telescope (Swift-BAT) searches for gamma-ray/X-ray counterparts to gravitational-wave (GW) candidate events identified during the third observing run of the Advanced LIGO and Advanced Virgo detectors. Using Fermi-GBM onboard triggers and subthreshold gamma-ray burst (GRB) candidates found in the Fermi-GBM ground analyses, the Targeted Search and the Untargeted Search, we investigate whether there are any coincident GRBs associated with the GWs. We also search the Swift-BAT rate data around the GW times to determine whether a GRB counterpart is present. No counterparts are found. Using both the Fermi-GBM Targeted Search and the Swift-BAT search, we calculate flux upper limits and present joint upper limits on the gamma-ray luminosity of each GW. Given these limits, we constrain theoretical models for the emission of gamma rays from binary black hole mergers

Acceptability, Feasibility and Feedback Analysis of Perception for Objective Structured Practical Examination As an Assessment Tool in Undergraduate in Competency Based Medical Education

Background: There is an increasing tendency to use Objective Structured Practical examination (OSPE) as an evaluation tool of practical performance in medical education. Aim and Objectives: The objective of the present study was to determine the acceptability and feasibility of OSPE as an assessment tool of formative examination by feedback analysis in the microbiology nd subject in 2 year MBBS undergraduate students and to discuss the pros and cons of OSPE method. Material and Methods: A well organized comprehensive ten OSPE stations were arranged to assess the practical nd skills of 2 year MBBS students in the department of microbiology. The practical performance skill of 50 second year undergraduate MBBS students were assessed by OSPE for microbiology subject by creating 10 structured stations of OSPE. The stations were written so as to cover major important practical nd microbiology topics of 2 year MBBS. The practical tasks chosen for the OSPE were mapped as per learning objectives of the course and the expected level of learning of the students. Results: A qualitative feedback from the examiners/ observers and the students was taken to assess acceptability feasibility of OSPE assessment. The examiners and the students were asked to rate OSPE by five point Likert scale Questionnaires. For the majority of students (92%) and examiners/ observers (100%) OSPE session was acceptable (p < 0.001). All examiners perceived OSPE method as feasible assessment tool (p < 0.001). Majority of the examiners and the students were in agreement or strongly in agreement in Likert scale rating for feedback analysis of OSPE session. There was no significant statistical difference among students and examiners/observers (Chi-squre:1.5184; DF:5; p= 0.8234). Conclusions: The OSPE is reliable and reproducible practical assessment tool and yields dependable information about the practical performance capabilities and competence of individual student and can be used as an additional assessing tool in competency based medical education. We favor introduction of OSPE method of evaluation in our setup as it covers all domains and different aspects

Co-infection of Hepatitis A and Hepatitis E Viruses among the Acute Viral Hepatitis Cases in Tertiary Care Hospital –A Four Years Retrospective Study

Acute viral hepatitis(AVH) is caused by Hepatitis A (HAV) and Hepatitis E(HEV). It is major health burden in India. Both the viruses HAV and HEV are primarily transmitted via the faeco-oral course. Study was conducted to determine the seroprevalence of HAV, HEV and rate of co-infection in AVH patients attending rural tertiary care centre. A retrospective laboratory record based study was carried out in rural tertiary health care center located in Western Maharashtra. Laboratory and Medical records of suspected acute viral infection patients were analyzed during study. Study period was June 2014 to July 2018. Commercially available ELISA kits of IgM anti-HAV and IgM anti-HEV were used to analyze serum samples of suspected study participants. Tests were carried out as per the manufacturer’s instructions. A total of 778 acute viral hepatitis cases were included in the study from July 2014 to July 2018 among which 85/778 (10.9 %) detected positive for HAV and 121/778 (15.6%) detected positive for HEV. Co-infection was identified in 6/778(0.8 %). Jaundice, fever fatigue and hepatomegaly were common clinical presentation in HAV, HEV and confection with both viruses in acute viral hepatitis patients. Study indicated low exposure to HAV in childhood bellow 16 years. Co-infection rate was detected high in 16-25 years age group. Vaccination policy against HAV in adolescent age group needed as there is change epidemiological shift of HAV which has been observed in the current study. These data will helps for planning future vaccination strategies, better implementation sanitation program, and safe water supply in this geographic area