235 results match your criteria Astroparticle Physics[Journal]

Revealing x-ray and gamma ray temporal and spectral similarities in the GRB 190829A afterglow.

Science 2021 06;372(6546):1081-1085

Department of Physics and Electrical Engineering, Linnaeus University, 351 95 Växjö, Sweden.

Gamma-ray bursts (GRBs), which are bright flashes of gamma rays from extragalactic sources followed by fading afterglow emission, are associated with stellar core collapse events. We report the detection of very-high-energy (VHE) gamma rays from the afterglow of GRB 190829A, between 4 and 56 hours after the trigger, using the High Energy Stereoscopic System (H.E. Read More

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New Limit for Neutrinoless Double-Beta Decay of ^{100}Mo from the CUPID-Mo Experiment.

Phys Rev Lett 2021 May;126(18):181802

Dipartimento di Fisica, Università di Milano-Bicocca, I-20126 Milano, Italy.

The CUPID-Mo experiment at the Laboratoire Souterrain de Modane (France) is a demonstrator for CUPID, the next-generation ton-scale bolometric 0νββ experiment. It consists of a 4.2 kg array of 20 enriched Li_{2}^{100}MoO_{4} scintillating bolometers to search for the lepton-number-violating process of 0νββ decay in ^{100}Mo. Read More

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Seasonal variation and sources of carbonaceous species and elements in PM and PM over the eastern Himalaya.

Environ Sci Pollut Res Int 2021 May 14. Epub 2021 May 14.

CSIR-National Physical Laboratory, Dr. K. S. Krishnan Road, New Delhi, 110 012, India.

The study represents the seasonal characteristics (carbonaceous aerosols and elements) and the contribution of prominent sources of PM and PM in the high altitude of the eastern Himalaya (Darjeeling) during August 2018-July 2019. Carbonaceous aerosols [organic carbon (OC), elemental carbon (EC), and water soluble organic carbon (WSOC)] and elements (Al, Fe, Ti, Cu, Zn, Mn, Cr, Ni, Mo, Cl, P, S, K, Zr, Pb, Na, Mg, Ca, and B) in PM and PM were analyzed to estimate their possible sources. The annual concentrations of PM and PM were computed as 37±12 μg m and 58±18 μg m, respectively. Read More

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Zinc stable isotope analysis reveals Zn dyshomeostasis in benign tumours, breast cancer, and adjacent histologically normal tissue.

Metallomics 2021 May;13(6)

Department of Earth Science & Engineering, Imperial College London, Exhibition Road, London SW7 2AZ, UK.

The disruption of Zn homeostasis has been linked with breast cancer development and progression. To enhance our understanding of changes in Zn homeostasis both inside and around the tumour microenvironment, Zn concentrations and isotopic compositions (δ66Zn) were determined in benign (BT) and malignant (MT) tumours, healthy tissue from reduction mammoplasty (HT), and histologically normal tissue adjacent to benign (NAT(BT)) and malignant tumours (NAT(MT)). Mean Zn concentrations in NAT(BT) are 5. Read More

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Elliptic Flow of Electrons from Beauty-Hadron Decays in Pb-Pb Collisions at sqrt[s_{NN}]=5.02  TeV.

Phys Rev Lett 2021 Apr;126(16):162001

Central China Normal University, Wuhan, China.

The elliptic flow of electrons from beauty hadron decays at midrapidity (|y|<0.8) is measured in Pb-Pb collisions at sqrt[s_{NN}]=5.02  TeV with the ALICE detector at the LHC. Read More

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Exoplanets as Sub-GeV Dark Matter Detectors.

Phys Rev Lett 2021 Apr;126(16):161101

Center for Cosmology and AstroParticle Physics (CCAPP), The Ohio State University, Columbus, Ohio 43210, USA.

We present exoplanets as new targets to discover dark matter (DM). Throughout the Milky Way, DM can scatter, become captured, deposit annihilation energy, and increase the heat flow within exoplanets. We estimate upcoming infrared telescope sensitivity to this scenario, finding actionable discovery or exclusion searches. Read More

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The novel Mechanical Ventilator Milano for the COVID-19 pandemic.

Phys Fluids (1994) 2021 Mar 23;33(3):037122. Epub 2021 Mar 23.

Camozzi Group S.p.A., Brescia BS 25126, Italy.

This paper presents the Mechanical Ventilator Milano (MVM), a novel intensive therapy mechanical ventilator designed for rapid, large-scale, low-cost production for the COVID-19 pandemic. Free of moving mechanical parts and requiring only a source of compressed oxygen and medical air to operate, the MVM is designed to support the long-term invasive ventilation often required for COVID-19 patients and operates in pressure-regulated ventilation modes, which minimize the risk of furthering lung trauma. The MVM was extensively tested against ISO standards in the laboratory using a breathing simulator, with good agreement between input and measured breathing parameters and performing correctly in response to fault conditions and stability tests. Read More

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Cosmic ray flux and lockdown due to COVID-19 in Kolkata - Any correlation?

Pramana 2021 17;95(2):64. Epub 2021 Apr 17.

Department of Physics and Centre for Astroparticle Physics and Space Science, Bose Institute, EN-80, Sector V, Kolkata, 700 091 India.

Cosmic ray muon flux is measured by the coincidence technique using plastic scintillation detectors in the High Energy Physics Detector Laboratory at Bose Institute, Kolkata. Due to the COVID-19 outbreak and nationwide complete lockdown, the laboratory was closed from the end of March 2020 till the end of May 2020. After lockdown, although the city is not in its normal state, we still were able to take data on some days. Read More

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Dark Energy Survey Year 1 Results: Cosmological Constraints from Cluster Abundances, Weak Lensing, and Galaxy Correlations.

Phys Rev Lett 2021 Apr;126(14):141301

Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.

We present the first joint analysis of cluster abundances and auto or cross-correlations of three cosmic tracer fields: galaxy density, weak gravitational lensing shear, and cluster density split by optical richness. From a joint analysis (4×2pt+N) of cluster abundances, three cluster cross-correlations, and the auto correlations of the galaxy density measured from the first year data of the Dark Energy Survey, we obtain Ω_{m}=0.305_{-0. Read More

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SARS-CoV-2 Is a Culprit for Some, but Not All Acute Ischemic Strokes: A Report from the Multinational COVID-19 Stroke Study Group.

J Clin Med 2021 Mar 1;10(5). Epub 2021 Mar 1.

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

Background: SARS-CoV-2 infected patients are suggested to have a higher incidence of thrombotic events such as acute ischemic strokes (AIS). This study aimed at exploring vascular comorbidity patterns among SARS-CoV-2 infected patients with subsequent stroke. We also investigated whether the comorbidities and their frequencies under each subclass of TOAST criteria were similar to the AIS population studies prior to the pandemic. Read More

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Detectable Environmental Effects in GW190521-like Black-Hole Binaries with LISA.

Phys Rev Lett 2021 Mar;126(10):101105

Max-Planck-Institut für Gravitationsphysik, Albert-Einstein-Institut, Am Mühlenberg 1,14476 Potsdam-Golm, Germany.

GW190521 is the compact binary with the largest masses observed to date, with at least one black hole in the pair-instability gap. This event has also been claimed to be associated with an optical flare observed by the Zwicky Transient Facility in an active galactic nucleus (AGN), possibly due to the postmerger motion of the merger remnant in the AGN gaseous disk. The Laser Interferometer Space Antenna (LISA) may detect up to ten such gas-rich black-hole binaries months to years before their detection by Laser Interferometer Gravitational Wave Observatory or Virgo-like interferometers, localizing them in the sky within ≈1°^{2}. Read More

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Search for Coherent Elastic Scattering of Solar ^{8}B Neutrinos in the XENON1T Dark Matter Experiment.

Phys Rev Lett 2021 Mar;126(9):091301

Institute for Astroparticle Physics, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany.

We report on a search for nuclear recoil signals from solar ^{8}B neutrinos elastically scattering off xenon nuclei in XENON1T data, lowering the energy threshold from 2.6 to 1.6  keV. Read More

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Bound on 3+1 Active-Sterile Neutrino Mixing from the First Four-Week Science Run of KATRIN.

Phys Rev Lett 2021 Mar;126(9):091803

Center for Experimental Nuclear Physics and Astrophysics, and Deptartment of Physics, University of Washington, Seattle, Washington 98195, USA.

We report on the light sterile neutrino search from the first four-week science run of the KATRIN experiment in 2019. Beta-decay electrons from a high-purity gaseous molecular tritium source are analyzed by a high-resolution MAC-E filter down to 40 eV below the endpoint at 18.57 keV. Read More

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A flexible framework for anomaly Detection via dimensionality reduction.

Neural Comput Appl 2021 Mar 11:1-11. Epub 2021 Mar 11.

Département de Physique Théorique and Center for Astroparticle Physics, University of Geneva, Geneva, Switzerland.

Anomaly detection is challenging, especially for large datasets in high dimensions. Here, we explore a general anomaly detection framework based on dimensionality reduction and unsupervised clustering. DRAMA is released as a general python package that implements the general framework with a wide range of built-in options. Read More

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Unusual Near-Horizon Cosmic-Ray-like Events Observed by ANITA-IV.

Phys Rev Lett 2021 Feb;126(7):071103

Department of Physics and Astronomy, University of Hawaii, Manoa, Hawaii 96822, USA.

ANITA's fourth long-duration balloon flight in 2016 detected 29 cosmic-ray (CR)-like events on a background of 0.37_{-0.17}^{+0. Read More

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February 2021

Three-dimensional imaging of xylem at cell wall level through near field nano holotomography.

Sci Rep 2021 Feb 25;11(1):4574. Epub 2021 Feb 25.

Thünen-Institute of Wood Research, Leuschnerstraße 91, Hamburg-Bergedorf, 21031, Hamburg, Germany.

Detailed imaging of the three-dimensionally complex architecture of xylary plants is important for studying biological and mechanical functions of woody plants. Apart from common two-dimensional microscopy, X-ray micro-computed tomography has been established as a three-dimensional (3D) imaging method for studying the hydraulic function of wooden plants. However, this X-ray imaging method can barely reach the resolution needed to see the minute structures (e. Read More

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February 2021

GW190521 Mass Gap Event and the Primordial Black Hole Scenario.

Phys Rev Lett 2021 Feb;126(5):051101

Département de Physique Théorique and Centre for Astroparticle Physics (CAP), Université de Genève, 24 quai E. Ansermet, CH-1211 Geneva, Switzerland.

The LIGO/Virgo Collaboration has recently observed GW190521, the first binary black hole merger with at least the primary component mass in the mass gap predicted by the pair-instability supernova theory. This observation disfavors the standard stellar-origin formation scenario for the heavier black hole, motivating alternative hypotheses. We show that GW190521 cannot be explained within the primordial black hole (PBH) scenario if PBHs do not accrete during their cosmological evolution, since this would require an abundance which is already in tension with current constraints. Read More

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February 2021

Cygnus X-1 contains a 21-solar mass black hole-Implications for massive star winds.

Science 2021 03 18;371(6533):1046-1049. Epub 2021 Feb 18.

Dr. Karl Remeis-Sternwarte and Erlangen Centre for Astroparticle Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg, 96049 Bamberg, Germany.

The evolution of massive stars is influenced by the mass lost to stellar winds over their lifetimes. These winds limit the masses of the stellar remnants (such as black holes) that the stars ultimately produce. We used radio astrometry to refine the distance to the black hole x-ray binary Cygnus X-1, which we found to be [Formula: see text] kiloparsecs. Read More

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NANOGrav Data Hints at Primordial Black Holes as Dark Matter.

Phys Rev Lett 2021 Jan;126(4):041303

Département de Physique Théorique and Centre for Astroparticle Physics (CAP), Université de Genève, 24 quai Ernest Ansermet, CH-1211 Geneva, Switzerland.

The NANOGrav Collaboration has recently published strong evidence for a stochastic common-spectrum process that may be interpreted as a stochastic gravitational wave background. We show that such a signal can be explained by second-order gravitational waves produced during the formation of primordial black holes from the collapse of sizeable scalar perturbations generated during inflation. This possibility has two predictions: (i) the primordial black holes may comprise the totality of the dark matter with the dominant contribution to their mass function falling in the range (10^{-15}÷10^{-11})M_{⊙} and (ii) the gravitational wave stochastic background will be seen as well by the Laser Interferometer Space Antenna experiment. Read More

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January 2021

Potential Gravitational Wave Signatures of Quantum Gravity.

Phys Rev Lett 2021 Jan;126(4):041302

Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803-4001, USA.

We show that gravitational wave astronomy has the potential to inform us on quantum aspects of black holes. Based on Bekenstein's quantization, we find that black hole area discretization could impart observable imprints to the gravitational wave signal from a pair of merging black holes, affecting their absorption properties during inspiral and their late-time relaxation after merger. In contrast with previous results, we find that black hole rotation, ubiquitous in astrophysics, improves our ability to probe quantum effects. Read More

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January 2021

Direct Measurement of the Cosmic-Ray Carbon and Oxygen Spectra from 10  GeV/n to 2.2  TeV/n with the Calorimetric Electron Telescope on the International Space Station.

Phys Rev Lett 2020 Dec;125(25):251102

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

In this paper, we present the measurement of the energy spectra of carbon and oxygen in cosmic rays based on observations with the Calorimetric Electron Telescope on the International Space Station from October 2015 to October 2019. Analysis, including the detailed assessment of systematic uncertainties, and results are reported. The energy spectra are measured in kinetic energy per nucleon from 10  GeV/n to 2. Read More

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December 2020

High-Precision Determination of Oxygen K_{α} Transition Energy Excludes Incongruent Motion of Interstellar Oxygen.

Phys Rev Lett 2020 Dec;125(24):243001

Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany.

We demonstrate a widely applicable technique to absolutely calibrate the energy scale of x-ray spectra with experimentally well-known and accurately calculable transitions of highly charged ions, allowing us to measure the K-shell Rydberg spectrum of molecular O_{2} with 8 meV uncertainty. We reveal a systematic ∼450  meV shift from previous literature values, and settle an extraordinary discrepancy between astrophysical and laboratory measurements of neutral atomic oxygen, the latter being calibrated against the aforementioned O_{2} literature values. Because of the widespread use of such, now deprecated, references, our method impacts on many branches of x-ray absorption spectroscopy. Read More

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December 2020

Detection of large-scale X-ray bubbles in the Milky Way halo.

Nature 2020 12 9;588(7837):227-231. Epub 2020 Dec 9.

Dr. Karl-Remeis-Sternwarte Bamberg and Erlangen Centre for Astroparticle Physics, Universität Erlangen-Nürnberg, Bamberg, Germany.

The halo of the Milky Way provides a laboratory to study the properties of the shocked hot gas that is predicted by models of galaxy formation. There is observational evidence of energy injection into the halo from past activity in the nucleus of the Milky Way; however, the origin of this energy (star formation or supermassive-black-hole activity) is uncertain, and the causal connection between nuclear structures and large-scale features has not been established unequivocally. Here we report soft-X-ray-emitting bubbles that extend approximately 14 kiloparsecs above and below the Galactic centre and include a structure in the southern sky analogous to the North Polar Spur. Read More

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December 2020

Spectroscopic Studies on the Biomolecular Recognition of Toluidine Blue: Key Information Towards Development of a Non-Contact, Non-Invasive Device for Oral Cancer Detection.

Front Oncol 2020 27;10:529132. Epub 2020 Oct 27.

Technical Research Centre, S. N. Bose National Centre for Basic Sciences, Kolkata, India.

Molecular interaction of aromatic dyes with biological macromolecules are important for the development of minimally invasive disease diagnostic biotechnologies. In the present work, we have used Toluidine Blue (TB) as a model dye, which is a well-known staining agent for the diagnosis of oral cancer and have studied the interaction of various biological macromolecules (protein and DNA) with the dye at different pH. Our spectroscopic studies confirm that TB interacts with Human Serum Albumin (HSA), a model protein at very high pH conditions which is very hard to achieve physiologically. Read More

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October 2020

Measurement of the Low-Energy Antideuteron Inelastic Cross Section.

Phys Rev Lett 2020 Oct;125(16):162001

Central China Normal University, Wuhan, China.

In this Letter, we report the first measurement of the inelastic cross section for antideuteron-nucleus interactions at low particle momenta, covering a range of 0.3≤p<4  GeV/c. The measurement is carried out using p-Pb collisions at a center-of-mass energy per nucleon-nucleon pair of sqrt[s_{NN}]=5. Read More

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October 2020

eV-Scale Sterile Neutrino Search Using Eight Years of Atmospheric Muon Neutrino Data from the IceCube Neutrino Observatory.

Phys Rev Lett 2020 Oct;125(14):141801

Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627, USA.

The results of a 3+1 sterile neutrino search using eight years of data from the IceCube Neutrino Observatory are presented. A total of 305 735 muon neutrino events are analyzed in reconstructed energy-zenith space to test for signatures of a matter-enhanced oscillation that would occur given a sterile neutrino state with a mass-squared differences between 0.01 and 100  eV^{2}. Read More

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October 2020

Gravitational Test beyond the First Post-Newtonian Order with the Shadow of the M87 Black Hole.

Phys Rev Lett 2020 Oct;125(14):141104

Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030, People's Republic of China.

The 2017 Event Horizon Telescope (EHT) observations of the central source in M87 have led to the first measurement of the size of a black-hole shadow. This observation offers a new and clean gravitational test of the black-hole metric in the strong-field regime. We show analytically that spacetimes that deviate from the Kerr metric but satisfy weak-field tests can lead to large deviations in the predicted black-hole shadows that are inconsistent with even the current EHT measurements. Read More

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October 2020

New Freezeout Mechanism for Strongly Interacting Dark Matter.

Phys Rev Lett 2020 Sep;125(13):131301

Center for Cosmology and AstroParticle Physics (CCAPP), The Ohio State University, Columbus, Ohio 43210, USA.

We present a new mechanism for thermally produced dark matter, based on a semi-annihilation-like process, χ+χ+SM→χ+SM, with intriguing consequences for the properties of dark matter. First, its mass is low, ≲1  GeV (but ≳5  keV to avoid structure-formation constraints). Second, it is strongly interacting, leading to kinetic equilibrium between the dark and visible sectors, avoiding the structure-formation problems of χ+χ+χ→χ+χ models. Read More

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September 2020