Institution
Centro Federal de Educação Tecnológica Celso Suckow da Fonseca
Education•Rio de Janeiro, Brazil•
About: Centro Federal de Educação Tecnológica Celso Suckow da Fonseca is a education organization based out in Rio de Janeiro, Brazil. It is known for research contribution in the topics: Cosmic ray & Pierre Auger Observatory. The organization has 788 authors who have published 998 publications receiving 5546 citations.
Topics: Cosmic ray, Pierre Auger Observatory, Ultimate tensile strength, Observatory, Context (language use)
Papers published on a yearly basis
Papers
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TL;DR: In this paper, a new analysis of the data set from the Pierre Auger Observatory provides evidence for anisotropy in the arrival directions of ultra-high-energy cosmic rays on an intermediate angular scale, which is indicative of excess arrivals from strong, nearby sources.
Abstract: A new analysis of the data set from the Pierre Auger Observatory provides evidence for anisotropy in the arrival directions of ultra-high-energy cosmic rays on an intermediate angular scale, which is indicative of excess arrivals from strong, nearby sources. The data consist of 5514 events above 20 EeV with zenith angles up to 80 recorded before 2017 April 30. Sky models have been created for two distinct populations of extragalactic gamma-ray emitters: active galactic nuclei from the second catalog of hard Fermi-LAT sources (2FHL) and starburst galaxies from a sample that was examined with Fermi-LAT. Flux-limited samples, which include all types of galaxies from the Swift-BAT and 2MASS surveys, have been investigated for comparison. The sky model of cosmic-ray density constructed using each catalog has two free parameters, the fraction of events correlating with astrophysical objects, and an angular scale characterizing the clustering of cosmic rays around extragalactic sources. A maximum-likelihood ratio test is used to evaluate the best values of these parameters and to quantify the strength of each model by contrast with isotropy. It is found that the starburst model fits the data better than the hypothesis of isotropy with a statistical significance of 4.0σ, the highest value of the test statistic being for energies above 39 EeV. The three alternative models are favored against isotropy with 2.7σ-3.2σ significance. The origin of the indicated deviation from isotropy is examined and prospects for more sensitive future studies are discussed.
243 citations
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TL;DR: The presence of microplastics in different organs of the crab supports the assumption that these particles have the potential to harm marine invertebrates.
192 citations
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TL;DR: In this paper, the authors search for high-energy neutrinos from the binary neutron star merger in the GeV-EeV energy range using the Antares, IceCube, and Pierre Auger Observatories.
Abstract: The Advanced LIGO and Advanced Virgo observatories recently discovered gravitational waves from a binary neutron star inspiral. A short gamma-ray burst (GRB) that followed the merger of this binary was also recorded by the Fermi Gamma-ray Burst Monitor (Fermi-GBM), and the Anti-Coincidence Shield for the Spectrometer for the International Gamma-Ray Astrophysics Laboratory (INTEGRAL), indicating particle acceleration by the source. The precise location of the event was determined by optical detections of emission following the merger. We searched for high-energy neutrinos from the merger in the GeV–EeV energy range using the Antares, IceCube, and Pierre Auger Observatories. No neutrinos directionally coincident with the source were detected within ±500 s around the merger time. Additionally, no MeV neutrino burst signal was detected coincident with the merger. We further carried out an extended search in the direction of the source for high-energy neutrinos within the 14 day period following the merger, but found no evidence of emission. We used these results to probe dissipation mechanisms in relativistic outflows driven by the binary neutron star merger. The non-detection is consistent with model predictions of short GRBs observed at a large off-axis angle.
189 citations
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TL;DR: In this paper, the authors combine previous work on quantifying the greenhouse gas value of ecosystems with models of the effects of biophysical processes to produce an integrated metric of climate-regulation services.
Abstract: This study combines previous work on quantifying the greenhouse gas value of ecosystems with models of the effects of biophysical processes to produce an integrated metric of climate-regulation services. The approach is used to quantify climate-regulation values of natural and managed ecosystems across the Western Hemisphere.
186 citations
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TL;DR: Both press-focusing and application of a lens proved to be useful beam focusing methods for high frequency transducers and under equal gain schemes, the LiNbO/sub 3/ and PbTiO/ sub 3/ transducers provided better image contrast than the other materials.
Abstract: The performance of high frequency, single-element transducers depends greatly on the mechanical and electrical properties of the piezoelectric materials used. This study compares the design and performance of transducers incorporating different materials. The materials investigated include 1-3 lead zirconate titanate (PZT) fiber composite, lead titanate (PbTiO/sub 3/) ceramic, poly(vinylidene fluoride) (PVDF) film, and lithium niobate (LiNbO/sub 3/) single crystal. All transducers were constructed with a 3-mm aperture size and an f-number between 2 and 3. Backing and matching materials were selected based on design goals and fabrication limitations. A simplified coaxial cable tuning method was employed to match the transducer impedance to 50 /spl Omega/ for the PZT fiber composite and PbTiO/sub 3/ ceramic transducers. Transducers were tested for two-way loss and -6 dB bandwidth using the pulse/echo response from a flat quartz target. Two-way loss varied from 21 to 46 dB, and bandwidths measured were in the range from 47 to 118%. In vitro ultrasonic backscatter microscope (UBM) images of an excised human eye were obtained for each device and used to compare imaging performance. Both press-focusing and application of a lens proved to be useful beam focusing methods for high frequency. Under equal gain schemes, the LiNbO/sub 3/ and PbTiO/sub 3/ transducers provided better image contrast than the other materials.
120 citations
Authors
Showing all 795 results
Name | H-index | Papers | Citations |
---|---|---|---|
Shankar P. Bhattacharyya | 43 | 290 | 9724 |
Mariana D. Banea | 35 | 98 | 4189 |
Sérgio Souto Maior Tavares | 31 | 178 | 2975 |
Claudio J. A. Mota | 27 | 108 | 2826 |
Eduardo Ogasawara | 22 | 124 | 1817 |
Juan Manuel Pardal | 20 | 103 | 1523 |
Marcelo Franco | 18 | 89 | 848 |
A. L. F. de Barros | 16 | 61 | 795 |
Pedro Manuel Calas Lopes Pacheco | 15 | 59 | 967 |
Vilma A. Oliveira | 15 | 106 | 825 |
S. de Barros | 13 | 32 | 659 |
Alessandro Jacoud Peixoto | 13 | 56 | 515 |
Davy William Hidalgo Chávez | 12 | 29 | 264 |
R. Suresh Babu | 12 | 20 | 495 |
Diego B. Haddad | 11 | 80 | 337 |