5,439 research outputs found

    Global aspects of gravitomagnetism

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    We consider global properties of gravitomagnetism by investigating the gravitomagnetic field of a rotating cosmic string. We show that although the gravitomagnetic field produced by such a configuration of matter vanishes locally, it can be detected globally. In this context we discuss the gravitational analogue of the Aharonov-Bohm effect.Comment: 10 pages - Typeset using REVTE

    The GREATS Hβ\beta+[OIII] Luminosity Function and Galaxy Properties at z8\mathbf{z\sim8}: Walking the Way of JWST

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    The James Webb Space Telescope will allow to spectroscopically study an unprecedented number of galaxies deep into the reionization era, notably by detecting [OIII] and Hβ\beta nebular emission lines. To efficiently prepare such observations, we photometrically select a large sample of galaxies at z8z\sim8 and study their rest-frame optical emission lines. Combining data from the GOODS Re-ionization Era wide-Area Treasury from Spitzer (GREATS) survey and from HST, we perform spectral energy distribution (SED) fitting, using synthetic SEDs from a large grid of photoionization models. The deep Spitzer/IRAC data combined with our models exploring a large parameter space enables to constrain the [OIII]+Hβ\beta fluxes and equivalent widths for our sample, as well as the average physical properties of z8z\sim8 galaxies, such as the ionizing photon production efficiency with log(ξion/erg1Hz)25.77\log(\xi_\mathrm{ion}/\mathrm{erg}^{-1}\hspace{1mm}\mathrm{Hz})\geq25.77. We find a relatively tight correlation between the [OIII]+Hβ\beta and UV luminosity, which we use to derive for the first time the [OIII]+Hβ\beta luminosity function (LF) at z8z\sim8. The z8z\sim8 [OIII]+Hβ\beta LF is higher at all luminosities compared to lower redshift, as opposed to the UV LF, due to an increase of the [OIII]+Hβ\beta luminosity at a given UV luminosity from z3z\sim3 to z8z\sim8. Finally, using the [OIII]+Hβ\beta LF, we make predictions for JWST/NIRSpec number counts of z8z\sim8 galaxies. We find that the current wide-area extragalactic legacy fields are too shallow to use JWST at maximal efficiency for z8z\sim8 spectroscopy even at 1hr depth and JWST pre-imaging to 30\gtrsim30 mag will be required.Comment: 13 pages, 9 figures, accepted for publication in MNRA

    Intensificação ecológica da agricultura: uma opção para a preservação ambiental com lucratividade.

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    As perspectivas futuras sugerem que uma verdadeira revolução nos processos de produção agrícola terá que acontecer. Se por um lado o modelo produtivista, oriundo da revolução verde, tem mostrado seus limites, principalmente no que diz respeito ao uso insustentável de recursos naturais e nos impactos negativos que causam ao meio ambiente, por outro, estima-se que a população mundial deverá chegar a 9 bilhões de pessoas em 2050, aumentando assim a demanda por alimentos, fibras, madeiras e, junte-se a essa lista: biocombustíveis. Esse aumento na demanda será ainda maior do que uma simples progressão do aumento populacional, já que uma substancial melhora na qualidade de vida das populações menos favorecidas é esperada. Essa melhora na qualidade de vida terá que passar, inevitavelmente, por um maior uso per capta de produtos provenientes da agricultura.bitstream/item/123090/1/Intensificacao-Ecologica.pd

    New optimal tests of quantum nonlocality

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    We explore correlation polytopes to derive a set of all Boole-Bell type conditions of possible classical experience which are both maximal and complete. These are compared with the respective quantum expressions for the Greenberger-Horne-Zeilinger (GHZ) case and for two particles with spin state measurements along three directions.Comment: 10 page

    Calagem melhora a disponibilidade de cálcio no solo e a produtividade de Ilex paraguariensis St. Hil.

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    Avaliou-se a influência da calagem na disponibilidade de Ca2+ no solo, produtividade e teor foliar de Ca e Al em erva-mate. Instalaram-se experimentos em três locais, avaliando-se cinco doses superficiais de calcário dolomítico para atingir 50 % das seguintes saturações por bases: 0, 30, 60, 90 e 120 %. Após 18 meses, avaliou-se: teor de Ca2+ no solo em três profundidades; teor foliar de Ca e Al e produtividade de erva-mate comercial (ECOM). A calagem, não alterou o teor foliar de Ca, mas, reduziu o de Al. A calagem, aumentou o teor de Ca 2+ no solo e, a produtividade de ECOM entre 21 e 27 %. Em solos com baixa disponibilidade natural de Ca 2+, a calagem deve disponibilizá-lo entre 4,0-4,5 cmol c dm-3 na profundidade de 0-5 cm, já em solos com alta disponibilidade de Ca 2+, a calagem deve disponibilizar o nutriente até 6,0 cmolc dm-3 para o cultivo da erva-mate

    Adubação potássica e intervalos de colheita influenciam o potássio do solo e a produtividade de cultivos de erva-mate.

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    O trabalho objetivou avaliar a adubação potássica e intervalos de colheita na disponibilidade de potássio, produtividade e distribuição do conteúdo de potássio na massa colhida da erva-mate. Avaliaram-se doses de 0, 20, 40, 80, 160 e 320 kg ha-1 de K2O para colheitas com intervalos de 12, 18 e 24 meses. Quantificou-se a disponibilidade de potássio em duas profundidades do solo e a produtividade de erva-mate comercial (ECOM) e galho grosso (GG) e distribuição do conteúdo de K nesses componentes. A adubação potássica aumentou a disponibilidade de potássio no solo e aumentou a produtividade da erva-mate. Para cultivos em solos com disponibilidade em nível baixo de potássio, recomenda-se doses próximas a 190, 270 e 320 kg ha-1 de K2O, respectivamente, para colheitas com intervalos de 12, 18 e 24 meses. Na retirada do GG da área, requer adubação de reposição do potássio adicional entre 20 a 30 %

    A transit timing analysis of nine RISE light curves of the exoplanet system TrES-3

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    We present nine newly observed transits of TrES-3, taken as part of a transit timing program using the RISE instrument on the Liverpool Telescope. A Markov-Chain Monte-Carlo analysis was used to determine the planet-star radius ratio and inclination of the system, which were found to be Rp/Rstar=0.1664^{+0.0011}_{-0.0018} and i = 81.73^{+0.13}_{-0.04} respectively, consistent with previous results. The central transit times and uncertainties were also calculated, using a residual-permutation algorithm as an independent check on the errors. A re-analysis of eight previously published TrES-3 light curves was conducted to determine the transit times and uncertainties using consistent techniques. Whilst the transit times were not found to be in agreement with a linear ephemeris, giving chi^2 = 35.07 for 15 degrees of freedom, we interpret this to be the result of systematics in the light curves rather than a real transit timing variation. This is because the light curves that show the largest deviation from a constant period either have relatively little out-of-transit coverage, or have clear systematics. A new ephemeris was calculated using the transit times, and was found to be T_c(0) = 2454632.62610 +- 0.00006 HJD and P = 1.3061864 +- 0.0000005 days. The transit times were then used to place upper mass limits as a function of the period ratio of a potential perturbing planet, showing that our data are sufficiently sensitive to have probed for sub-Earth mass planets in both interior and exterior 2:1 resonances, assuming the additional planet is in an initially circular orbit.Comment: 21 pages, 4 figures, Accepted for publication in Ap

    Mist and Edge Computing Cyber-Physical Human-Centered Systems for Industry 5.0: A Cost-Effective IoT Thermal Imaging Safety System

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    While many companies worldwide are still striving to adjust to Industry 4.0 principles, the transition to Industry 5.0 is already underway. Under such a paradigm, Cyber-Physical Human-centered Systems (CPHSs) have emerged to leverage operator capabilities in order to meet the goals of complex manufacturing systems towards human-centricity, resilience and sustainability. This article first describes the essential concepts for the development of Industry 5.0 CPHSs and then analyzes the latest CPHSs, identifying their main design requirements and key implementation components. Moreover, the major challenges for the development of such CPHSs are outlined. Next, to illustrate the previously described concepts, a real-world Industry 5.0 CPHS is presented. Such a CPHS enables increased operator safety and operation tracking in manufacturing processes that rely on collaborative robots and heavy machinery. Specifically, the proposed use case consists of a workshop where a smarter use of resources is required, and human proximity detection determines when machinery should be working or not in order to avoid incidents or accidents involving such machinery. The proposed CPHS makes use of a hybrid edge computing architecture with smart mist computing nodes that processes thermal images and reacts to prevent industrial safety issues. The performed experiments show that, in the selected real-world scenario, the developed CPHS algorithms are able to detect human presence with low-power devices (with a Raspberry Pi 3B) in a fast and accurate way (in less than 10 ms with a 97.04% accuracy), thus being an effective solution that can be integrated into many Industry 5.0 applications. Finally, this article provides specific guidelines that will help future developers and managers to overcome the challenges that will arise when deploying the next generation of CPHSs for smart and sustainable manufacturing.Comment: 32 page
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