266 research outputs found

    Cronología de la erupción dentaria en caninos superiores e inferiores

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    Objectives: To establish the chronological sequence of the dental eruption in canines, carrying out various investigations in different studies that indicate, according to their analyzes, that there is a direct relationship with the factors that cause their eruption to be altered. Methods: A bibliographic review was carried out from October to December 2020, using the following search strategy in the database: Scielo, Repository, Medical journals, within which 22 articles related to the subject were considered, taking into account that 90% of the publications and bibliographic reviews were from 2010-2020. Results: In different studies a close relationship was found in the different factors that tend to cause the advance or delay in its appearance. That is why it is necessary to consider investigating the biological factors that can affect the development of the tooth bud. Conclusion: All the information that has been obtained in this investigation, we conclude that the order of eruption of the mentioned teeth, whether they are upper and lower canines, is affected and is influenced by components such as malnutrition, geographical environment, climate, race, factor environmental, sex and age.Objetivos: Establecer la secuencia cronolog√≠a de la erupci√≥n dentaria en caninos, realizando diversas investigaciones en diferentes estudios que indican seg√ļn sus an√°lisis que existe relaci√≥n directa con los factores que hacen que su erupci√≥n se vea alterada. M√©todos: Se realiz√≥ una revisi√≥n bibliogr√°fica a partir de octubre hasta diciembre del 2020, empleando la siguiente estrategia de b√ļsqueda en la base de datos: Scielo, Repositorio, Revistas m√©dicas dentro de los cuales se consider√≥ 22 art√≠culos relacionados con el tema, tomando en cuenta que el 90% de las publicaciones y revisiones bibliogr√°ficas fueron del 2010 ‚Äď 2020. Resultados: En diferentes estudios se encontraron una estrecha relaci√≥n en los diferentes factores que tienden a provocar el adelanto o retraso en su aparici√≥n. Es por ello que se necesita considerar investigar los factores biol√≥gicos que pueden afectar el desarrollo del brote de los dientes. Conclusi√≥n: Toda la informaci√≥n que se ha podido obtener en esta investigaci√≥n, concluimos que el orden de erupci√≥n de los dientes mencionados, sean caninos superiores e inferiores se ve afectada e influyen los componentes como la desnutrici√≥n, el medio geogr√°fico, el clima, la raza, factor ambiental, sexo y edad

    Computational thinking and robotics in education

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    After the computational thinking sessions in the previous 2016-2018 editions of TEEM Conference, the fourth edition of this track has been organized in the current 2019 edition. Computational thinking is still a very significant topic, especially, but not only, in pre-university education. In this edition, the robotic has a special role in the track, with a strength relationship with the STEM and STEAM education of children at the pre-university levels, seeding the future of our society

    All-particle cosmic ray energy spectrum measured by the HAWC experiment from 10 to 500 TeV

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    We report on the measurement of the all-particle cosmic ray energy spectrum with the High Altitude Water Cherenkov (HAWC) Observatory in the energy range 10 to 500 TeV. HAWC is a ground based air-shower array deployed on the slopes of Volcan Sierra Negra in the state of Puebla, Mexico, and is sensitive to gamma rays and cosmic rays at TeV energies. The data used in this work were taken from 234 days between June 2016 to February 2017. The primary cosmic-ray energy is determined with a maximum likelihood approach using the particle density as a function of distance to the shower core. Introducing quality cuts to isolate events with shower cores landing on the array, the reconstructed energy distribution is unfolded iteratively. The measured all-particle spectrum is consistent with a broken power law with an index of ‚ąí2.49¬Ī0.01-2.49\pm0.01 prior to a break at (45.7¬Ī0.1(45.7\pm0.1) TeV, followed by an index of ‚ąí2.71¬Ī0.01-2.71\pm0.01. The spectrum also respresents a single measurement that spans the energy range between direct detection and ground based experiments. As a verification of the detector response, the energy scale and angular resolution are validated by observation of the cosmic ray Moon shadow's dependence on energy.Comment: 16 pages, 11 figures, 4 tables, submission to Physical Review

    Constraining the pňČ/p\bar{p}/p Ratio in TeV Cosmic Rays with Observations of the Moon Shadow by HAWC

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    An indirect measurement of the antiproton flux in cosmic rays is possible as the particles undergo deflection by the geomagnetic field. This effect can be measured by studying the deficit in the flux, or shadow, created by the Moon as it absorbs cosmic rays that are headed towards the Earth. The shadow is displaced from the actual position of the Moon due to geomagnetic deflection, which is a function of the energy and charge of the cosmic rays. The displacement provides a natural tool for momentum/charge discrimination that can be used to study the composition of cosmic rays. Using 33 months of data comprising more than 80 billion cosmic rays measured by the High Altitude Water Cherenkov (HAWC) observatory, we have analyzed the Moon shadow to search for TeV antiprotons in cosmic rays. We present our first upper limits on the pňČ/p\bar{p}/p fraction, which in the absence of any direct measurements, provide the tightest available constraints of ‚ąľ1%\sim1\% on the antiproton fraction for energies between 1 and 10 TeV.Comment: 10 pages, 5 figures. Accepted by Physical Review

    Search for very-high-energy emission from Gamma-ray Bursts using the first 18 months of data from the HAWC Gamma-ray Observatory

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    The High Altitude Water Cherenkov (HAWC) Gamma-ray Observatory is an extensive air shower detector operating in central Mexico, which has recently completed its first two years of full operations. If for a burst like GRB 130427A at a redshift of 0.34 and a high-energy component following a power law with index -1.66, the high-energy component is extended to higher energies with no cut-off other than from extragalactic background light attenuation, HAWC would observe gamma rays with a peak energy of ‚ąľ\sim300 GeV. This paper reports the results of HAWC observations of 64 gamma-ray bursts (GRBs) detected by Swift\mathit{Swift} and Fermi\mathit{Fermi}, including three GRBs that were also detected by the Large Area Telescope (Fermi\mathit{Fermi}-LAT). An ON/OFF analysis method is employed, searching on the time scale given by the observed light curve at keV-MeV energies and also on extended time scales. For all GRBs and time scales, no statistically significant excess of counts is found and upper limits on the number of gamma rays and the gamma-ray flux are calculated. GRB 170206A, the third brightest short GRB detected by the Gamma-ray Burst Monitor on board the Fermi\mathit{Fermi} satellite (Fermi\mathit{Fermi}-GBM) and also detected by the LAT, occurred very close to zenith. The LAT measurements can neither exclude the presence of a synchrotron self-Compton (SSC) component nor constrain its spectrum. Instead, the HAWC upper limits constrain the expected cut-off in an additional high-energy component to be less than 100¬†GeV100~\rm{GeV} for reasonable assumptions about the energetics and redshift of the burst.Comment: 19 pages, 6 figures, published in Ap

    Very high energy particle acceleration powered by the jets of the microquasar SS 433

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    SS 433 is a binary system containing a supergiant star that is overflowing its Roche lobe with matter accreting onto a compact object (either a black hole or neutron star). Two jets of ionized matter with a bulk velocity of ‚ąľ0.26c\sim0.26c extend from the binary, perpendicular to the line of sight, and terminate inside W50, a supernova remnant that is being distorted by the jets. SS 433 differs from other microquasars in that the accretion is believed to be super-Eddington, and the luminosity of the system is ‚ąľ1040\sim10^{40} erg s‚ąí1^{-1}. The lobes of W50 in which the jets terminate, about 40 pc from the central source, are expected to accelerate charged particles, and indeed radio and X-ray emission consistent with electron synchrotron emission in a magnetic field have been observed. At higher energies (>100 GeV), the particle fluxes of ő≥\gamma rays from X-ray hotspots around SS 433 have been reported as flux upper limits. In this energy regime, it has been unclear whether the emission is dominated by electrons that are interacting with photons from the cosmic microwave background through inverse-Compton scattering or by protons interacting with the ambient gas. Here we report TeV ő≥\gamma-ray observations of the SS 433/W50 system where the lobes are spatially resolved. The TeV emission is localized to structures in the lobes, far from the center of the system where the jets are formed. We have measured photon energies of at least 25 TeV, and these are certainly not Doppler boosted, because of the viewing geometry. We conclude that the emission from radio to TeV energies is consistent with a single population of electrons with energies extending to at least hundreds of TeV in a magnetic field of ‚ąľ16\sim16~micro-Gauss.Comment: Preprint version of Nature paper. Contacts: S. BenZvi, B. Dingus, K. Fang, C.D. Rho , H. Zhang, H. Zho
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