Repeat pregnancy among urban adolescents: sociodemographic, family, and health factors

First-time adolescent mothers are at high risk for a repeat pregnancy. The present investigation, part of an ongoing longitudinal study, examined sociodemographic, family, and health factors associated with repeat Pregnancy in a clinic sample of urban, first-time adolescent mothers (ages 13 to 17 years). They were predominantly African-American and from low-income households. Repeat pregnancy within one year and between one and two years postpartum was determined from medical records. Summary statistics, point biserial correlations, and chi-square statistics were used to analyze the data. Results indicated that postpartum contraceptive method was associated with repeat pregnancy at Year 1; contraceptive use, maternal age, history of miscarriages, and postpartum contraceptive method were associated with repeat pregnancy at Year 2. It was concluded that efforts to prevent repeat pregnancies among first-time adolescent mothers should include the continuous monitoring of contraceptive use, as well as the promotion of long-acting contraceptives (e.g., medroxyprogesterone or progesterone implants). Further, counseling should be offered to adolescent mothers with a history offered miscarriages

Investigating the effect of precession on searches for neutron-star-black-hole binaries with Advanced LIGO

The first direct detection of neutron-star-black-hole binaries will likely be made with gravitational-wave observatories. Advanced LIGO and Advanced Virgo will be able to observe neutron-star-black-hole mergers at a maximum distance of 900Mpc. To acheive this sensitivity, gravitational-wave searches will rely on using a bank of filter waveforms that accurately model the expected gravitational-wave signal. The angular momentum of the black hole is expected to be comparable to the orbital angular momentum. This angular momentum will affect the dynamics of the inspiralling system and alter the phase evolution of the emitted gravitational-wave signal. In addition, if the black hole's angular momentum is not aligned with the orbital angular momentum it will cause the orbital plane of the system to precess. In this work we demonstrate that if the effect of the black hole's angular momentum is neglected in the waveform models used in gravitational-wave searches, the detection rate of $(10+1.4)M_{\odot}$ neutron-star--black-hole systems would be reduced by $33 - 37$. The error in this measurement is due to uncertainty in the Post-Newtonian approximations that are used to model the gravitational-wave signal of neutron-star-black-hole inspiralling binaries. We describe a new method for creating a bank of filter waveforms where the black hole has non-zero angular momentum, but is aligned with the orbital angular momentum. With this bank we find that the detection rate of $(10+1.4)M_{\odot}$ neutron-star-black-hole systems would be reduced by $26-33$. Systems that will not be detected are ones where the precession of the orbital plane causes the gravitational-wave signal to match poorly with non-precessing filter waveforms. We identify the regions of parameter space where such systems occur and suggest methods for searching for highly precessing neutron-star-black-hole binaries

Extending the PyCBC search for gravitational waves from compact binary mergers to a global network

The worldwide advanced gravitational-wave (GW) detector network has so far primarily consisted of the two Advanced LIGO observatories at Hanford and Livingston, with Advanced Virgo joining the 2016-7 O2 observation run at a relatively late stage. However Virgo has been observing alongside the LIGO detectors since the start of the O3 run; in the near future, the KAGRA detector will join the global network and a further LIGO detector in India is under construction. Gravitational-wave search methods would therefore benefit from the ability to analyse data from an arbitrary network of detectors. In this paper we extend the PyCBC offline compact binary coalescence (CBC) search analysis to three or more detectors, and describe resulting updates to the coincident search and event ranking statistic. For a three-detector network, our improved multi-detector search finds 20% more simulated signals at fixed false alarm rate in idealized colored Gaussian noise, and up to 40% more in real data, compared to the two-detector analysis previously used during O2

A 3-Year Sample of Almost 1,600 Elves Recorded Above South America by the Pierre Auger Cosmic-Ray Observatory

©2020. The Authors. Elves are a class of transient luminous events, with a radial extent typically greater than 250 km, that occur in the lower ionosphere above strong electrical storms. We report the observation of 1,598 elves, from 2014 to 2016, recorded with unprecedented time resolution (100 ns) using the fluorescence detector (FD) of the Pierre Auger Cosmic-Ray Observatory. The Auger Observatory is located in the Mendoza province of Argentina with a viewing footprint for elve observations of 3.106 km2, reaching areas above the Pacific and Atlantic Oceans, as well as the Córdoba region, which is known for severe convective thunderstorms. Primarily designed for ultrahigh energy cosmic-ray observations, the Auger FD turns out to be very sensitive to the ultraviolet emission in elves. The detector features modified Schmidt optics with large apertures resulting in a field of view that spans the horizon, and year-round operation on dark nights with low moonlight background, when the local weather is favorable. The measured light profiles of 18% of the elve events have more than one peak, compatible with intracloud activity. Within the 3-year sample, 72% of the elves correlate with the far-field radiation measurements of the World Wide Lightning Location Network. The Auger Observatory plans to continue operations until at least 2025, including elve observations and analysis. To the best of our knowledge, this observatory is the only facility on Earth that measures elves with year-round operation and full horizon coverage

A Catalog of the Highest-energy Cosmic Rays Recorded during Phase I of Operation of the Pierre Auger Observatory

A catalog containing details of the highest-energy cosmic rays recorded through the detection of extensive air showers at the Pierre Auger Observatory is presented with the aim of opening the data to detailed examination. Descriptions of the 100 showers created by the highest-energy particles recorded between 2004 January 1 and 2020 December 31 are given for cosmic rays that have energies in the range 78-166 EeV. Details are also given on a further nine very energetic events that have been used in the calibration procedure adopted to determine the energy of each primary. A sky plot of the arrival directions of the most energetic particles is shown. No interpretations of the data are offered

Testing effects of Lorentz invariance violation in the propagation of astroparticles with the Pierre Auger Observatory

Lorentz invariance violation (LIV) is often described by dispersion relations of the form E i2 = m i2+p i2+δi,n E 2+n with delta different based on particle type i, with energy E, momentum p and rest mass m. Kinematics and energy thresholds of interactions are modified once the LIV terms become comparable to the squared masses of the particles involved. Thus, the strongest constraints on the LIV coefficients δi,n tend to come from the highest energies. At sufficiently high energies, photons produced by cosmic ray interactions as they propagate through the Universe could be subluminal and unattenuated over cosmological distances. Cosmic ray interactions can also be modified and lead to detectable fingerprints in the energy spectrum and mass composition observed on Earth. The data collected at the Pierre Auger Observatory are therefore possibly sensitive to both the electromagnetic and hadronic sectors of LIV. In this article, we explore these two sectors by comparing the energy spectrum and the composition of cosmic rays and the upper limits on the photon flux from the Pierre Auger Observatory with simulations including LIV. Constraints on LIV parameters depend strongly on the mass composition of cosmic rays at the highest energies. For the electromagnetic sector, while no constraints can be obtained in the absence of protons beyond 1019 eV, we obtain δγ,0 \u3e -10-21, δγ,1 \u3e -10-40 eV-1 and δγ,2 \u3e -10-58 eV-2 in the case of a subdominant proton component up to 1020 eV. For the hadronic sector, we study the best description of the data as a function of LIV coefficients and we derive constraints in the hadronic sector such as δhad,0 \u3c 10-19, δhad,1 \u3c 10-38 eV-1 and δhad,2 \u3c 10-57 eV-2 at 5σ CL

Measurement of the Fluctuations in the Number of Muons in Extensive Air Showers with the Pierre Auger Observatory

We present the first measurement of the fluctuations in the number of muons in extensive air showers produced by ultrahigh energy cosmic rays. We find that the measured fluctuations are in good agreement with predictions from air shower simulations. This observation provides new insights into the origin of the previously reported deficit of muons in air shower simulations and constrains models of hadronic interactions at ultrahigh energies. Our measurement is compatible with the muon deficit originating from small deviations in the predictions from hadronic interaction models of particle production that accumulate as the showers develop

Design and implementation of the AMIGA embedded system for data acquisition

The Auger Muon Infill Ground Array (AMIGA) is part of the AugerPrime upgrade of the Pierre Auger Observatory. It consists of particle counters buried 2.3 m underground next to the water-Cherenkov stations that form the 23.5 km2 large infilled array. The reduced distance between detectors in this denser area allows the lowering of the energy threshold for primary cosmic ray reconstruction down to about 1017 eV. At the depth of 2.3 m the electromagnetic component of cosmic ray showers is almost entirely absorbed so that the buried scintillators provide an independent and direct measurement of the air showers muon content. This work describes the design and implementation of the AMIGA embedded system, which provides centralized control, data acquisition and environment monitoring to its detectors. The presented system was firstly tested in the engineering array phase ended in 2017, and lately selected as the final design to be installed in all new detectors of the production phase. The system was proven to be robust and reliable and has worked in a stable manner since its first deployment

Deep-learning based reconstruction of the shower maximum Xmax using the water-Cherenkov detectors of the Pierre Auger Observatory

The atmospheric depth of the air shower maximum Xmax is an observable commonly used for the determination of the nuclear mass composition of ultra-high energy cosmic rays. Direct measurements of Xmax are performed using observations of the longitudinal shower development with fluorescence telescopes. At the same time, several methods have been proposed for an indirect estimation of Xmax from the characteristics of the shower particles registered with surface detector arrays. In this paper, we present a deep neural network (DNN) for the estimation of Xmax. The reconstruction relies on the signals induced by shower particles in the ground based water-Cherenkov detectors of the Pierre Auger Observatory. The network architecture features recurrent long short-term memory layers to process the temporal structure of signals and hexagonal convolutions to exploit the symmetry of the surface detector array. We evaluate the performance of the network using air showers simulated with three different hadronic interaction models. Thereafter, we account for long-term detector effects and calibrate the reconstructed Xmax using fluorescence measurements. Finally, we show that the event-by-event resolution in the reconstruction of the shower maximum improves with increasing shower energy and reaches less than 25 g/cm2 at energies above 2×1019 eV