293 results match your criteria Astroparticle Physics[Journal]

Scattering Searches for Dark Matter in Subhalos: Neutron Stars, Cosmic Rays, and Old Rocks.

Phys Rev Lett 2022 Jun;128(23):231801

TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada.

In many cosmologies dark matter clusters on subkiloparsec scales and forms compact subhalos, in which the majority of Galactic dark matter could reside. Null results in direct detection experiments since their advent four decades ago could then be the result of extremely rare encounters between the Earth and these subhalos. We investigate alternative and promising means to identify subhalo dark matter interacting with standard model particles: (1) subhalo collisions with old neutron stars can transfer kinetic energy and brighten the latter to luminosities within the reach of imminent infrared, optical, and ultraviolet telescopes; we identify new detection strategies involving single-star measurements and Galactic disk surveys, and obtain the first bounds on self-interacting dark matter in subhalos from the coldest known pulsar, PSR J2144-3933; (2) subhalo dark matter scattering with cosmic rays results in detectable effects; (3) historic Earth-subhalo encounters can leave dark matter tracks in Paleolithic minerals deep underground. Read More

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Sharp Signals of Boson Clouds in Black Hole Binary Inspirals.

Phys Rev Lett 2022 Jun;128(22):221102

Gravitation Astroparticle Physics Amsterdam (GRAPPA), University of Amsterdam, Amsterdam 1098 XH, Netherlands.

Gravitational waves (GWs) are an exciting new probe of physics beyond the standard models of gravity and particle physics. One interesting possibility is provided by the so-called "gravitational atom," wherein a superradiant instability spontaneously forms a cloud of ultralight bosons around a rotating black hole. The presence of these boson clouds affects the dynamics of black hole binary inspirals and their associated GW signals. Read More

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Uranium: an overview of physicochemical properties, exposure assessment methodologies, and health effects of environmental and occupational exposure.

Environ Geochem Health 2022 Jun 16. Epub 2022 Jun 16.

Department of Geoscience and Geological Engineering, Queen's University, 99 University Avenue, Kingston, ON, K7L 3N6, Canada.

Uranium is chemo- and radiotoxic element which can cause multifactorial health hazards. Natural and anthropogenic uranium contamination raises concerns about potential public health problems. Natural contamination plays a significant role with regard to uranium exposure in the general population, whereas anthropogenic contamination leads to occupational uranium exposure, particularly in nuclear industry workers. Read More

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Monopoles from an Atmospheric Fixed Target Experiment.

Phys Rev Lett 2022 May;128(20):201101

Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo Institutes for Advanced Study, The University of Tokyo, Kashiwa 277-8583, Japan.

Magnetic monopoles have a long history of theoretical predictions and experimental searches, carrying direct implications for fundamental concepts such as electric charge quantization. We analyze in detail for the first time magnetic monopole production from collisions of cosmic rays bombarding the atmosphere. This source of monopoles is independent of cosmology, has been active throughout Earth's history, and supplies an irreducible monopole flux for all terrestrial experiments. Read More

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µRA-A New Compact Easy-to-Use Raman System for All Hydrogen Isotopologues.

Sensors (Basel) 2022 May 23;22(10). Epub 2022 May 23.

Tritium Laboratory Karlsruhe, Institute for Astroparticle Physics, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany.

We have developed a new compact and cost-efficient Laser-Raman system for the simultaneous measurement of all six hydrogen isotopologues. The focus of this research was set on producing a tool that can be implemented in virtually any existing setup providing in situ process control and analytics. The "micro Raman (µRA)" system is completely fiber-coupled for an easy setup consisting of (i) a spectrometer/CCD unit, (ii) a 532 nm laser, and (iii) a commercial Raman head coupled with a newly developed, tritium-compatible all-metal sealed DN16CF flange/Raman window serving as the process interface. Read More

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Impact of Dark Compton Scattering on Direct Dark Matter Absorption Searches.

Phys Rev Lett 2022 May;128(19):191801

Department of Physics, Stanford University, Stanford, California 94305, USA.

Direct detection experiments are gaining in mass reach. Here we show that the inclusion of dark Compton scattering, which has typically been neglected in absorption searches, has a substantial impact on the reach and discovery potential of direct detection experiments at high bosonic cold dark matter masses. We demonstrate this for relic dark photons and axionlike particles: we improve expected reach across materials, and further use results from SuperCDMS, EDELWEISS, and GERDA to place enhanced limits on dark matter parameter space. Read More

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Emerging applications of high-precision Cu isotopic analysis by MC-ICP-MS.

Sci Total Environ 2022 Sep 20;838(Pt 2):156084. Epub 2022 May 20.

Department of Geological Sciences and Geological Engineering, Queens University, Kingston, ON, Canada; Arthur B. McDonald Canadian Astroparticle Physics Research Institute, Department of Physics, Engineering Physics & Astronomy, Queen's University, Kingston, Ontario, Canada.

As a component of many minerals and an essential trace element in most aerobic organisms, the transition metal element Cu is important for studying reduction-oxidation (redox) interactions and metal cycling in the total environment (lithosphere, atmosphere, biosphere, hydrosphere, and anthroposphere). The "fractionation" or relative partitioning of the naturally occurring "heavy" (Cu) and "light" (Cu) isotope between two coexisting phases in a system occurs according to bonding environment and/or as a result of a slight difference in the rate at which these isotopes take part in physical processes and chemical reactions (in absence of equilibrium). Due to this behaviour, Cu isotopic analysis can be used to study a range of geochemical and biological processes that cannot be elucidated with Cu concentrations alone. Read More

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September 2022

Polarization of Λ and Λ[over ¯] Hyperons along the Beam Direction in Pb-Pb Collisions at sqrt[s]_{NN}=5.02  TeV.

Phys Rev Lett 2022 Apr;128(17):172005

Nikhef, National institute for subatomic physics, Amsterdam, Netherlands.

The polarization of the Λ and Λ[over ¯] hyperons along the beam (z) direction, P_{z}, has been measured in Pb-Pb collisions at sqrt[s_{NN}]=5.02  TeV recorded with ALICE at the Large Hadron Collider (LHC). The main contribution to P_{z} comes from elliptic flow-induced vorticity and can be characterized by the second Fourier sine coefficient P_{z,s2}=⟨P_{z}sin(2φ-2Ψ_{2})⟩, where φ is the hyperon azimuthal emission angle and Ψ_{2} is the elliptic flow plane angle. Read More

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X-ray detection of a nova in the fireball phase.

Nature 2022 05 11;605(7909):248-250. Epub 2022 May 11.

Institut für Astronomie und Astrophysik, Kepler Center for Astro and Particle Physics, Eberhard Karls Universität, Tübingen, Germany.

Novae are caused by runaway thermonuclear burning in the hydrogen-rich envelopes of accreting white dwarfs, which leads to a rapid expansion of the envelope and the ejection of most of its mass. Theory has predicted the existence of a 'fireball' phase following directly on from the runaway fusion, which should be observable as a short, bright and soft X-ray flash before the nova becomes visible in the optical. Here we report observations of a bright and soft X-ray flash associated with the classical Galactic nova YZ Reticuli 11 h before its 9 mag optical brightening. Read More

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Simple and statistically sound recommendations for analysing physical theories.

Rep Prog Phys 2022 Apr 29;85(5). Epub 2022 Apr 29.

Department of Physics, Shahid Beheshti University, Tehran, Iran.

Physical theories that depend on many parameters or are tested against data from many different experiments pose unique challenges to statistical inference. Many models in particle physics, astrophysics and cosmology fall into one or both of these categories. These issues are often sidestepped with statistically unsound ad hoc methods, involving intersection of parameter intervals estimated by multiple experiments, and random or grid sampling of model parameters. Read More

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Single-exposure X-ray phase imaging microscopy with a grating interferometer.

J Synchrotron Radiat 2022 May 15;29(Pt 3):794-806. Epub 2022 Mar 15.

Erlangen Centre for Astroparticle Physics (ECAP), Friedrich-Alexander-Universität Erlangen-Nürnberg, Erwin-Rommel-Strasse 1, D-91058 Erlangen, Germany.

The advent of hard X-ray free-electron lasers enables nanoscopic X-ray imaging with sub-picosecond temporal resolution. X-ray grating interferometry offers a phase-sensitive full-field imaging technique where the phase retrieval can be carried out from a single exposure alone. Thus, the method is attractive for imaging applications at X-ray free-electron lasers where intrinsic pulse-to-pulse fluctuations pose a major challenge. Read More

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Growth, structure, and temperature dependent emission processes in emerging metal hexachloride scintillators CsHfCl and CsZrCl.

Dalton Trans 2022 May 3;51(17):6944-6954. Epub 2022 May 3.

Lviv Polytechnic National University, 12 Bandera Str., Lviv 79013, Ukraine.

Crystals of metal hexachlorides CsMCl (M = Hf or Zr) have recently emerged as promising materials for scintillation applications due to their excellent energy resolution. In this work, we investigated the crystal structure and scintillation properties of CsHfCl and CsZrCl crystals in the broad temperature range from 9 to 300 K. X-ray diffraction data confirmed the same cubic structure (space group ) for CsHfCl and CsZrCl over the entire examined temperature range. Read More

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Direct Measurement of the Nickel Spectrum in Cosmic Rays in the Energy Range from 8.8  GeV/n to 240  GeV/n with CALET on the International Space Station.

Phys Rev Lett 2022 Apr;128(13):131103

National Institute of Polar Research, 10-3, Midori-cho, Tachikawa, Tokyo 190-8518, Japan.

The relative abundance of cosmic ray nickel nuclei with respect to iron is by far larger than for all other transiron elements; therefore it provides a favorable opportunity for a low background measurement of its spectrum. Since nickel, as well as iron, is one of the most stable nuclei, the nickel energy spectrum and its relative abundance with respect to iron provide important information to estimate the abundances at the cosmic ray source and to model the Galactic propagation of heavy nuclei. However, only a few direct measurements of cosmic-ray nickel at energy larger than ∼3  GeV/n are available at present in the literature, and they are affected by strong limitations in both energy reach and statistics. Read More

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Detecting Subsolar-Mass Primordial Black Holes in Extreme Mass-Ratio Inspirals with LISA and Einstein Telescope.

Phys Rev Lett 2022 Mar;128(11):111104

Dipartimento di Fisica, Sapienza Università di Roma, Piazzale Aldo Moro 5, 00185 Roma, Italy.

Primordial black holes possibly formed in the early Universe could provide a significant fraction of the dark matter and would be unique probes of inflation. A smoking gun for their discovery would be the detection of a subsolar mass compact object. We argue that extreme mass-ratio inspirals will be ideal to search for subsolar-mass black holes not only with LISA but also with third-generation ground-based detectors such as Cosmic Explorer and the Einstein Telescope. Read More

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Measurement of the Groomed Jet Radius and Momentum Splitting Fraction in pp and Pb-Pb Collisions at sqrt[s_{NN}]=5.02  TeV.

Phys Rev Lett 2022 Mar;128(10):102001

Nikhef, National institute for subatomic physics, Amsterdam, Netherlands.

This article presents groomed jet substructure measurements in pp and Pb-Pb collisions at sqrt[s_{NN}]=5.02  TeV with the ALICE detector. The soft drop grooming algorithm provides access to the hard parton splittings inside a jet by removing soft wide-angle radiation. Read More

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A new generation of scintillation detectors with identification of events undergoing multiple interactions for gamma-ray imaging and spectroscopy.

Appl Radiat Isot 2022 Jun 9;184:110189. Epub 2022 Mar 9.

Dept. of Medico-Surgical Sciences and Biotechnologies, Sapienza University of Rome, P.le Aldo Moro 5, 00185, Rome, Italy.

The present work deals with a scintillation detector made of a LuYAP:Ce array coupled to a position-sensitive photo-multiplier tube, whose structure is well suitable for SPECT and PET, but also in nuclear physics, astrophysics, astroparticle physics, homeland security, and non-proliferation. The response was investigated under Co-57, Ba-133, Cs-137 gamma-ray irradiation, and with Lu-176 self-activity. The investigation, based on the 2-D charge-profiles spread, provides means for identifying and rejecting multiple-interactions in the crystal-array, like Lu X-ray escape photons, and Compton-scattered ones. Read More

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A new benchmark of soft X-ray transition energies of , , and : paving a pathway towards ppm accuracy.

Eur Phys J D At Mol Opt Phys 2022 1;76(3):38. Epub 2022 Mar 1.

NASA Goddard Space Flight Center, 8800 Greenbelt Rd., Greenbelt, MD 20771 USA.

Abstract: A key requirement for the correct interpretation of high-resolution X-ray spectra is that transition energies are known with high accuracy and precision. We investigate the K-shell features of , , and gases, by measuring their photo ion-yield spectra at the BESSY II synchrotron facility simultaneously with the 1s-p fluorescence emission of He-like ions produced in the Polar-X EBIT. Accurate calculations of transitions in these ions provide the basis of the calibration. Read More

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Time-resolved hadronic particle acceleration in the recurrent nova RS Ophiuchi.

Science 2022 04 10;376(6588):77-80. Epub 2022 Mar 10.

Institut für Astronomie und Astrophysik, Universität Tübingen, Sand 1, D 72076 Tübingen, Germany.

Recurrent novae are repeating thermonuclear explosions in the outer layers of white dwarfs, due to the accretion of fresh material from a binary companion. The shock generated when ejected material slams into the companion star's wind can accelerate particles. We report very-high-energy (VHE; [Formula: see text]) gamma rays from the recurrent nova RS Ophiuchi, up to 1 month after its 2021 outburst, observed using the High Energy Stereoscopic System (H. Read More

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The effect of mission duration on LISA science objectives.

Gen Relativ Gravit 2022 27;54(1). Epub 2021 Dec 27.

Dipartimento di Fisica, "Sapienza" Università di Roma and Sezione INFN Roma1, Piazzale Aldo Moro 5, 00185 Rome, Italy.

The science objectives of the LISA mission have been defined under the implicit assumption of a 4-years continuous data stream. Based on the performance of LISA Pathfinder, it is now expected that LISA will have a duty cycle of , which would reduce the effective span of usable data to 3 years. This paper reports the results of a study by the LISA Science Group, which was charged with assessing the additional science return of increasing the mission lifetime. Read More

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December 2021

Direct detection of dark matter-APPEC committee report.

Rep Prog Phys 2022 Apr 29;85(5). Epub 2022 Apr 29.

Institute of Physics, University of Freiburg, Freiburg, Germany.

This report provides an extensive review of the experimental programme of direct detection searches of particle dark matter. It focuses mostly on European efforts, both current and planned, but does it within a broader context of a worldwide activity in the field. It aims at identifying the virtues, opportunities and challenges associated with the different experimental approaches and search techniques. Read More

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Dilepton Rapidity Distribution in Drell-Yan Production to Third Order in QCD.

Phys Rev Lett 2022 Feb;128(5):052001

Zhejiang Institute of Modern Physics, Department of Physics, Zhejiang University, Hangzhou, 310027, China.

We compute for the first time the lepton-pair rapidity distribution in the photon-mediated Drell-Yan process to next-to-next-to-next-to-leading order in QCD. The calculation is based on the q_{T}-subtraction method, suitably extended to this order for quark-antiquark initiated Born processes. Our results display sizeable QCD corrections at next-to-next-to-next-to-leading order over the full rapidity region and provide a fully independent confirmation of the recent results for the total Drell-Yan cross section at this order. Read More

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February 2022

Search for Relativistic Magnetic Monopoles with Eight Years of IceCube Data.

Phys Rev Lett 2022 Feb;128(5):051101

Department of Physics, University of Maryland, College Park, Maryland 20742, USA.

We present an all-sky 90% confidence level upper limit on the cosmic flux of relativistic magnetic monopoles using 2886 days of IceCube data. The analysis was optimized for monopole speeds between 0.750c and 0. Read More

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February 2022

Synergies of THESEUS with the large facilities of the 2030s and guest observer opportunities.

Exp Astron (Dordr) 2021 7;52(3):407-437. Epub 2021 Jul 7.

Physics Department, Gubkin Russian State University, 65 Leninsky Prospekt, Moscow, 119991 Russian Federation.

The proposed THESEUS mission will vastly expand the capabilities to monitor the high-energy sky. It will specifically exploit large samples of gamma-ray bursts to probe the early universe back to the first generation of stars, and to advance multi-messenger astrophysics by detecting and localizing the counterparts of gravitational waves and cosmic neutrino sources. The combination and coordination of these activities with multi-wavelength, multi-messenger facilities expected to be operating in the 2030s will open new avenues of exploration in many areas of astrophysics, cosmology and fundamental physics, thus adding considerable strength to the overall scientific impact of THESEUS and these facilities. Read More

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Unsupervised pseudo CT generation using heterogenous multicentric CT/MR images and CycleGAN: Dosimetric assessment for 3D conformal radiotherapy.

Comput Biol Med 2022 Jan 31;143:105277. Epub 2022 Jan 31.

Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, CH-1211, Geneva 4, Switzerland; Geneva University Neurocenter, Geneva University, Geneva, Switzerland; Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, Netherlands; Department of Nuclear Medicine, University of Southern Denmark, Odense, Denmark.

Purpose: Absorbed dose calculation in magnetic resonance-guided radiation therapy (MRgRT) is commonly based on pseudo CT (pCT) images. This study investigated the feasibility of unsupervised pCT generation from MRI using a cycle generative adversarial network (CycleGAN) and a heterogenous multicentric dataset. A dosimetric analysis in three-dimensional conformal radiotherapy (3DCRT) planning was also performed. Read More

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January 2022

First Direct Detection Constraints on Planck-Scale Mass Dark Matter with Multiple-Scatter Signatures Using the DEAP-3600 Detector.

Phys Rev Lett 2022 Jan;128(1):011801

Department of Physics, Carleton University, Ottawa, Ontario, K1S 5B6, Canada.

Dark matter with Planck-scale mass (≃10^{19}  GeV/c^{2}) arises in well-motivated theories and could be produced by several cosmological mechanisms. A search for multiscatter signals from supermassive dark matter was performed with a blind analysis of data collected over a 813 d live time with DEAP-3600, a 3.3 t single-phase liquid argon-based detector at SNOLAB. Read More

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January 2022

Measurement of Prompt D^{0}, Λ_{c}^{+}, and Σ_{c}^{0,++}(2455) Production in Proton-Proton Collisions at sqrt[s]=13  TeV.

Phys Rev Lett 2022 Jan;128(1):012001

Horia Hulubei National Institute of Physics and Nuclear Engineering, Bucharest, Romania.

The p_{T}-differential production cross sections of prompt D^{0}, Λ_{c}^{+}, and Σ_{c}^{0,++}(2455) charmed hadrons are measured at midrapidity (|y|<0.5) in pp collisions at sqrt[s]=13  TeV. This is the first measurement of Σ_{c}^{0,++} production in hadronic collisions. Read More

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January 2022

Measurement of the Cross Sections of Ξ_{c}^{0} and Ξ_{c}^{+} Baryons and of the Branching-Fraction Ratio BR(Ξ_{c}^{0}→Ξ^{-}e^{+}ν_{e})/BR(Ξ_{c}^{0}→Ξ^{-}π^{+}) in pp Collisions at sqrt[s]=13  TeV.

Phys Rev Lett 2021 Dec;127(27):272001

Horia Hulubei National Institute of Physics and Nuclear Engineering, Bucharest, Romania.

The p_{T}-differential cross sections of prompt charm-strange baryons Ξ_{c}^{0} and Ξ_{c}^{+} were measured at midrapidity (|y|<0.5) in proton-proton (pp) collisions at a center-of-mass energy sqrt[s]=13  TeV with the ALICE detector at the LHC. The Ξ_{c}^{0} baryon was reconstructed via both the semileptonic decay (Ξ^{-}e^{+}ν_{e}) and the hadronic decay (Ξ^{-}π^{+}) channels. Read More

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December 2021

Risk of Subsequent Stroke Among Patients Receiving Outpatient vs Inpatient Care for Transient Ischemic Attack: A Systematic Review and Meta-analysis.

JAMA Netw Open 2022 01 4;5(1):e2136644. Epub 2022 Jan 4.

Neurology Department, Neuroscience Institute, Geisinger Health System, Danville, Pennsylvania.

Importance: Transient ischemic attack (TIA) often indicates a high risk of subsequent cerebral ischemic events. Timely preventive measures improve the outcome.

Objective: To estimate and compare the risk of subsequent ischemic stroke among patients with TIA or minor ischemic stroke (mIS) by care setting. Read More

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January 2022

Regimes of cosmic-ray diffusion in Galactic turbulence.

SN Appl Sci 2022 11;4(1):15. Epub 2021 Dec 11.

Department of Physics, University of Wisconsin-Madison, Madison, WI 53706 USA.

Cosmic-ray transport in astrophysical environments is often dominated by the diffusion of particles in a magnetic field composed of both a turbulent and a mean component. This process, which is two-fold turbulent mixing in that the particle motion is stochastic with respect to the field lines, needs to be understood in order to properly model cosmic-ray signatures. One of the most important aspects in the modeling of cosmic-ray diffusion is that fully resonant scattering, the most effective such process, is only possible if the wave spectrum covers the entire range of propagation angles. Read More

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December 2021

Artificial Intelligence: A Shifting Paradigm in Cardio-Cerebrovascular Medicine.

J Clin Med 2021 Dec 6;10(23). Epub 2021 Dec 6.

Geisinger Neuroscience Institute, Geisinger Health System, Danville, PA 17822, USA.

The future of healthcare is an organic blend of technology, innovation, and human connection. As artificial intelligence (AI) is gradually becoming a go-to technology in healthcare to improve efficiency and outcomes, we must understand our limitations. We should realize that our goal is not only to provide faster and more efficient care, but also to deliver an integrated solution to ensure that the care is fair and not biased to a group of sub-population. Read More

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December 2021