126 research outputs found
Neonatal Outcome in Caesarean Births for Unexplained Fetal Distress
Background: Appropriateness of caesarean section (CS) for foetal distress (FD) is proved by neonatal status at birth. Validity is known after intervention has been done, whether justified CS or not. It provides information about delays also.Objectives: Objectives were to know burden of CS for FD in women with no apparent risk factors, factors detected during CS, accuracy of diagnosis, whether really FD or false alarm.Material Methods: Five years records of births were analysed for knowing about CS for FD in women with no obvious risk factors, neither in history, nor clinical examination or day to day investigations which could have lead to diagnosis of FD. Approval of institute’s ethics committee was taken. Analysis of records of women who had CS (2121) performed for FD as primary indication, revealed that 38.15%, (809 of 2121 CS for FD), were study subjects, no risk factor.Clinical diagnosis of unexplained FD contributed to 10.6% of CS, 15.2% of emergency CS, 3.7% of births during study period. Details of CS, intra-operative findings, status of liquor amnii, placenta, umbilical cord vessels, status of baby at birth beyond were recorded.Results: Of 809 cases, 6 (0.8%) were teenagers, 569 (70.33%) of 20-24 yrs, 705 (87.14%) were primigravida, actually 95.67% were nullipara, highly significantly (P<0.01) more primigravida than over all 45% primigravida. 11.99%, (97 of 809) CS were performed at less than 34 weeks gestation. FD was diagnosed by any one or two or all three, nonstress test, moderate or thick meconium in liquor or persisting foetal tachycardia or bradycardia. NST recorded category – III (non reassuring foetal heart) in 395 (48.83%) women, in others 48.83% (395 of 809) it was moderate or thick meconium in liquor amnii, persistent foetal bradycardia, moderate (<100 bpm) or severe (<80 bpm) in 2.6%, (21 of 809), persisting foetal tachycardia (>180 bpm) in 6.18% (50 of 809). Baby was vigorous at birth in 353 (43.63%), 427 (52.78%) required NICU admission. Of them, 241 (56.44%) improved, survived, but 186 (43.56%) died, 29 (3.58%) were still born. Overall loss of 26.5% in CBs for FD is, a matter of concern.Conclusion: Many CS were performed in women without risk factors with diagnosis of FD. In quite a few it was proved that intervention was needed and also in some delayed too, but in some it seemed to be unwanted intervention. Studies are needed to search for non-conventional or unknown risk factors for FD, also for authentic modes of knowing non-reassuring foetal status. Once diagnosed it is essential to have best outcome by quick right, interventions
Guidelines for key organizational factors for saas organizations
© 2019 Association for Computing Machinery. Software as a Service is a new model of software deployment where a provider licenses an application to customers for use as a service on demand. Due to benefits offered by it, organizations are transferring towards the SaaS delivery model. As compared to traditional organizations, SaaS organizations must consider key factors to stand out in a competitive market. This paper provides a better understanding of key factors for SaaS organization and provides guidelines for these key factors for SaaS organization. Ultimately, these guidelines will be valuable for SaaS vendors to improve SaaS application performance
SPIRITS Catalog of Infrared Variables: Identification of Extremely Luminous Long Period Variables
We present a catalog of 417 luminous infrared variable stars with periods
exceeding 250 days. These were identified in 20 nearby galaxies by the ongoing
SPIRITS survey with the Spitzer Space Telescope. Of these, 359 variables have
(phase-weighted mean magnitudes) fainter than and periods and
luminosities consistent with previously reported variables in the Large
Magellanic Cloud. However, 58 variables are more luminous than , including 11 that are brighter than with the brightest
having . Most of these bright variable sources have
quasi-periods longer than 1000 days, including four over 2000 days. We suggest
that the fundamental period-luminosity relationship, previously measured for
the Large Magellanic Cloud, extends to much higher luminosities and longer
periods in this large galaxy sample. We posit that these variables include
massive AGB stars (possibly super-AGB stars), red supergiants experiencing
exceptionally high mass-loss rates, and interacting binaries. We also present
3.6, 4.5, 5.8 and 8.0 m photometric catalogs for all sources in these 20
galaxies.Comment: 18 pages, 25 figure
Multi-wavelength observations of the obscuring wind in the radio-quiet quasar MR 2251-178
Obscuring winds driven away from active supermassive black holes are rarely
seen due to their transient nature. They have been observed with
multi-wavelength observations in a few Seyfert 1 galaxies and one broad
absorption line radio-quiet quasar so far. An X-ray obscuration event in MR
2251-178 was caught in late 2020, which triggered multi-wavelength (NIR to
X-ray) observations targeting this radio-quiet quasar. In the X-ray band, the
obscurer leads to a flux drop in the soft X-ray band from late 2020 to early
2021. X-ray obscuration events might have a quasi-period of two decades
considering earlier events in 1980 and 1996. In the UV band, a forest of weak
blueshifted absorption features emerged in the blue wing of Ly
in late 2020. Our XMM-Newton, NuSTAR, and HST/COS observations
are obtained simultaneously, hence, the transient X-ray obscuration event is
expected to account for the UV outflow, although they are not necessarily
caused by the same part of the wind. Both blueshifted and redshifted absorption
features were found for He {\sc i} , but no previous NIR spectra
are available for comparison. The X-ray observational features of MR 2251-178
shared similarities with some other type 1 AGNs with obscuring wind. However,
observational features in the UV to NIR bands are distinctly different from
those seen in other AGN with obscuring winds. A general understanding of the
observational variety and the nature of obscuring wind is still lacking.Comment: ApJ accepte
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An ASKAP Search for a Radio Counterpart to the First High-significance Neutron Star-Black Hole Merger LIGO/Virgo S190814bv
We present results from a search for a radio transient associated with the LIGO/Virgo source S190814bv, a likely neutron star-black hole (NSBH) merger, with the Australian Square Kilometre Array Pathfinder. We imaged a 30 deg2 field at ΔT = 2, 9, and 33 days post-merger at a frequency of 944 MHz, comparing them to reference images from the Rapid ASKAP Continuum Survey observed 110 days prior to the event. Each epoch of our observations covers 89% of the LIGO/Virgo localization region. We conducted an untargeted search for radio transients in this field, resulting in 21 candidates. For one of these, AT2019osy, we performed multiwavelength follow-up and ultimately ruled out the association with S190814bv. All other candidates are likely unrelated variables, but we cannot conclusively rule them out. We discuss our results in the context of model predictions for radio emission from NSBH mergers and place constrains on the circum-merger density and inclination angle of the merger. This survey is simultaneously the first large-scale radio follow-up of an NSBH merger, and the most sensitive widefield radio transients search to-date
Progenitor, Precursor and Evolution of the Dusty Remnant of the Stellar Merger M31-LRN-2015
M31-2015-LRN is a likely stellar merger discovered in the Andromeda Galaxy in 2015. We present new optical to mid-infrared photometry and optical spectroscopy for this event. The transient brightened by ∼3 mag as compared to its progenitor. The complex precursor emission, which started ∼2 years before the nova event, may be explained by the binary undergoing Roche-lobe overflow. The dynamical mass loss from the outer Lagrange point L2 creates an optically thick outflow to power the observed brightening of the system. We find two possible periods of 16±0.3 and 28.1±1.4 days at different phases of the precursor lightcurve, possibly related to the geometry of the mass-loss from the binary. Although the progenitor spectral energy distribution shows no evidence of pre-existing warm dust in system, the remnant forms an optically thick dust shell 2−4 months after the outburst peak. The optical depth of the shell increases after 1.5 years, suggesting the existence of shocks that enhance the dust formation process. We propose that the merger remnant is likely an inflated giant obscured by a cooling shell of gas with mass ∼0.2 M⊙ ejected at the onset of the common envelope phase
Design requirements for the Wide-field Infrared Transient Explorer (WINTER)
The Wide-field Infrared Transient Explorer (WINTER) is a 1x1 degree infrared survey telescope under devel- opment at MIT and Caltech, and slated for commissioning at Palomar Observatory in 2021. WINTER is a seeing-limited infrared time-domain survey and has two main science goals: (1) the discovery of IR kilonovae and r-process materials from binary neutron star mergers and (2) the study of general IR transients, including supernovae, tidal disruption events, and transiting exoplanets around low mass stars. We plan to meet these science goals with technologies that are relatively new to astrophysical research: hybridized InGaAs sensors as an alternative to traditional, but expensive, HgCdTe arrays and an IR-optimized 1-meter COTS telescope. To mitigate risk, optimize development efforts, and ensure that WINTER meets its science objectives, we use model-based systems engineering (MBSE) techniques commonly featured in aerospace engineering projects. Even as ground-based instrumentation projects grow in complexity, they do not often have the budget for a full-time systems engineer. We present one example of systems engineering for the ground-based WINTER project, featuring software tools that allow students or staff to learn the fundamentals of MBSE and capture the results in a formalized software interface. We focus on the top-level science requirements with a detailed example of how the goal of detecting kilonovae flows down to WINTER’s optical design. In particular, we discuss new methods for tolerance simulations, eliminating stray light, and maximizing image quality of a fly’s-eye design that slices the telescope’s focus onto 6 non-buttable, IR detectors. We also include a discussion of safety constraints for a robotic telescope
Progenitor, Precursor and Evolution of the Dusty Remnant of the Stellar Merger M31-LRN-2015
M31-2015-LRN is a likely stellar merger discovered in the Andromeda Galaxy in
2015. We present new optical to mid-infrared photometry and optical
spectroscopy for this event. Archival data shows that the source started to
brighten 2 years before the nova event. During this precursor phase, the
source brightened by 3 mag. The lightcurve at 6 and 1.5 months before the
main outburst may show periodicity, with periods of 160.3 and 28.11.4
days respectively. This complex emission may be explained by runaway mass loss
from the system after the binary undergoes Roche-lobe overflow, leading the
system to coalesce in tens of orbital periods. While the progenitor spectral
energy distribution shows no evidence of pre-existing warm dust in system, the
remnant forms an optically thick dust shell at 4 months after the
outburst peak. The optical depth of the shell increases dramatically after 1.5
years, suggesting the existence of shocks that enhance the dust formation
process. We propose that the merger remnant is likely an inflated giant
obscured by a cooling shell of gas with mass M ejected at
the onset of the common envelope phase.Comment: 16 pages, 10 figures. Accepted for publication in MNRA
GROWTH on S190814bv: Deep Synoptic Limits on the Optical/Near-Infrared Counterpart to a Neutron Star-Black Hole Merger
On 2019 August 14, the Advanced LIGO and Virgo interferometers detected the high-significance gravitational wave (GW) signal S190814bv. The GW data indicated that the event resulted from a neutron star–black hole (NSBH) merger, or potentially a low-mass binary BH merger. Due to the low false-alarm rate and the precise localization (23 deg2 at 90%), S190814bv presented the community with the best opportunity yet to directly observe an optical/near-infrared counterpart to an NSBH merger. To search for potential counterparts, the GROWTH Collaboration performed real-time image subtraction on six nights of public Dark Energy Camera images acquired in the 3 weeks following the merger, covering >98% of the localization probability. Using a worldwide network of follow-up facilities, we systematically undertook spectroscopy and imaging of optical counterpart candidates. Combining these data with a photometric redshift catalog, we ruled out each candidate as the counterpart to S190814bv and placed deep, uniform limits on the optical emission associated with S190814bv. For the nearest consistent GW distance, radiative transfer simulations of NSBH mergers constrain the ejecta mass of S190814bv to be M_(ej) < 0.04 M⊙ at polar viewing angles, or M_(ej) < 0.03 M⊙ if the opacity is κ < 2 cm²g⁻¹. Assuming a tidal deformability for the NS at the high end of the range compatible with GW170817 results, our limits would constrain the BH spin component aligned with the orbital momentum to be χ < 0.7 for mass ratios Q < 6, with weaker constraints for more compact NSs
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