82 research outputs found

    What 'outliers' tell us about missed opportunities for tuberculosis control: a cross-sectional study of patients in Mumbai, India

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    BACKGROUND: India's Revised National Tuberculosis Control Programme (RNTCP) is deemed highly successful in terms of detection and cure rates. However, some patients experience delays in accessing diagnosis and treatment. Patients falling between the 96th and 100th percentiles for these access indicators are often ignored as atypical 'outliers' when assessing programme performance. They may, however, provide clues to understanding why some patients never reach the programme. This paper examines the underlying vulnerabilities of patients with extreme values for delays in accessing the RNTCP in Mumbai city, India. METHODS: We conducted a cross-sectional study with 266 new sputum positive patients registered with the RNTCP in Mumbai. Patients were classified as 'outliers' if patient, provider and system delays were beyond the 95th percentile for the respective variable. Case profiles of 'outliers' for patient, provider and system delays were examined and compared with the rest of the sample to identify key factors responsible for delays. RESULTS: Forty-two patients were 'outliers' on one or more of the delay variables. All 'outliers' had a significantly lower per capita income than the remaining sample. The lack of economic resources was compounded by social, structural and environmental vulnerabilities. Longer patient delays were related to patients' perception of symptoms as non-serious. Provider delays were incurred as a result of private providers' failure to respond to tuberculosis in a timely manner. Diagnostic and treatment delays were minimal, however, analysis of the 'outliers' revealed the importance of social support in enabling access to the programme. CONCLUSION: A proxy for those who fail to reach the programme, these case profiles highlight unique vulnerabilities that need innovative approaches by the RNTCP. The focus on 'outliers' provides a less resource- and time-intensive alternative to community-based studies for understanding the barriers to reaching public health programmes

    Search for continuous gravitational wave emission from the Milky Way center in O3 LIGO--Virgo data

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    We present a directed search for continuous gravitational wave (CW) signals emitted by spinning neutron stars located in the inner parsecs of the Galactic Center (GC). Compelling evidence for the presence of a numerous population of neutron stars has been reported in the literature, turning this region into a very interesting place to look for CWs. In this search, data from the full O3 LIGO--Virgo run in the detector frequency band [10,2000] Hz[10,2000]\rm~Hz have been used. No significant detection was found and 95%\% confidence level upper limits on the signal strain amplitude were computed, over the full search band, with the deepest limit of about 7.6×10267.6\times 10^{-26} at 142 Hz\simeq 142\rm~Hz. These results are significantly more constraining than those reported in previous searches. We use these limits to put constraints on the fiducial neutron star ellipticity and r-mode amplitude. These limits can be also translated into constraints in the black hole mass -- boson mass plane for a hypothetical population of boson clouds around spinning black holes located in the GC.Comment: 25 pages, 5 figure

    Search for subsolar-mass binaries in the first half of Advanced LIGO’s and Advanced Virgo’s third observing run

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    We report on a search for compact binary coalescences where at least one binary component has a mass between 0.2 M_\odot and 1.0 M_\odot in Advanced LIGO and Advanced Virgo data collected between 1 April 2019 1500 UTC and 1 October 2019 1500 UTC. We extend previous analyses in two main ways: we include data from the Virgo detector and we allow for more unequal mass systems, with mass ratio q \geq 0.1. We do not report any gravitational-wave candidates. The most significant trigger has a false alarm rate of 0.14 \mathrm{yr}^-1. This implies an upper limit on the merger rate of subsolar binaries in the range [220–24200] \mathrm{Gpc}^{-3} \, \mathrm{yr}^{-1}, depending on the chirp mass of the binary. We use this upper limit to derive astrophysical constraints on two phenomenological models that could produce subsolar-mass compact objects. One is an isotropic distribution of equal-mass primordial black holes. Using this model, we find that the fraction of dark matter in primordial black holes is f_\mathrm{PBH}\equiv \Omega_\mathrm{PBH}/\Omega_\mathrm{DM}\lesssim 6\%. The other is a dissipative dark matter model, in which fermionic dark matter can collapse and form black holes. The upper limit on the fraction of dark matter black holes depends on the minimum mass of the black holes that can be formed: the most constraining result is obtained at M_\mathrm{min}=1 M_\odot, where f_\mathrm{DBH}\equiv \Omega_\mathrm{PBH}/\Omega_\mathrm{DM}\lesssim 0.003\%. These are the tightest limits on spinning subsolar-mass binaries to date

    All-sky search for gravitational wave emission from scalar boson clouds around spinning black holes in LIGO O3 data

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    This paper describes the first all-sky search for long-duration, quasimonochromatic gravitational-wave signals emitted by ultralight scalar boson clouds around spinning black holes using data from the third observing run of Advanced LIGO. We analyze the frequency range from 20 to 610 Hz, over a small frequency derivative range around zero, and use multiple frequency resolutions to be robust towards possible signal frequency wanderings. Outliers from this search are followed up using two different methods, one more suitable for nearly monochromatic signals, and the other more robust towards frequency fluctuations. We do not find any evidence for such signals and set upper limits on the signal strain amplitude, the most stringent being ≈10−25 at around 130 Hz. We interpret these upper limits as both an “exclusion region” in the boson mass/black hole mass plane and the maximum detectable distance for a given boson mass, based on an assumption of the age of the black hole/boson cloud system

    Lowering of relaxor transition temperature in lead-based perovskites under pressure13;

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    The dielectric constants of lead iron niobate (PFN) and 40% lead zinc niobate (PZN) added to lead iron niobate (PFNo.6-PZNo.4) have been measured as a function of pressure up to 6 GPa under isothermal conditions between room temperature and 348 K. The relaxor transition temperature measured at 1 kHz excitation frequency varies at a rate -24.5 K/GPa for PFN and at a rate of -28.8 KiGPa for the PrIVo.6 -PZNo.4 composition
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