• Title/Summary/Keyword: University of Oxford

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Feedback-regulated star formation and escape of LyC photons from mini-haloes during reionization

  • Kimm, Taysun;Katz, Harley;Haehnelt, Martin;Rosdahl, Joakim;Devriendt, Julien;Slyz, Adrianne
    • The Bulletin of The Korean Astronomical Society
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    • v.43 no.1
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    • pp.57.1-57.1
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    • 2018
  • Reionisation in the early Universe is likely driven by dwarf galaxies. Using cosmological RHD simulations, we study star formation and the escape of Lyman continuum (LyC) photons from mini-haloes with Mhalo<108Msun. We find that feedback reduces star formation very efficiently in mini-haloes, resulting in the stellar mass consistent with the empirical stellar mass-to-halo mass relation derived in the local Universe. Because star formation is stochastic and dominated by a few gas clumps, the escape fraction in mini-haloes is generally determined by photo-ionization, rather than supernova explosions. We find that the photon number-weighted mean escape fraction in mini-haloes is higher (20-40%) than that in atomic-cooling haloes. Despite their high escape fractions, LyC photons from mini-haloes are of minor importance for reionization due to inefficient star formation. We confirm previous claims that stars in atomic-cooling haloes with masses $10^8M_{sun}$$10^{11}M_{sun}$ are likely to be the most important source of reionization.

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Beyond halo mass: the role of vorticity-rich filaments in quenching galaxy mass assembly

  • Song, Hyunmi;Laigle, Clotilde;Hwang, Ho Seong;Devriendt, Julien;Dubois, Yohan;Kraljic, Katarina;Pichon, Christophe;Slyz, Adrianne;Smith, Rory
    • The Bulletin of The Korean Astronomical Society
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    • v.45 no.1
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    • pp.39.1-39.1
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    • 2020
  • We examine how the mass assembly of central galaxies depends on their location in the cosmic web. The HORIZON-AGN simulation is analysed at z~2 using the DISPERSE code to extract multi-scale cosmic filaments. We find that the dependency of galaxy properties on large-scale environment is mostly inherited from the (large-scale) environmental dependency of their host halo mass. When adopting a residual analysis that removes the host halo mass effect, we detect a direct and non-negligible influence of cosmic filaments. Proximity to filaments enhances the build-up of stellar mass, a result in agreement with previous studies. However, our multi-scale analysis also reveals that, at the edge of filaments, star formation is suppressed. In addition, we find clues for compaction of the stellar distribution at close proximity to filaments. We suggest that gas transfer from the outside to the inside of the haloes (where galaxies reside) becomes less efficient closer to filaments, due to high angular momentum supply at the vorticity-rich edge of filaments. This quenching mechanism may partly explain the larger fraction of passive galaxies in filaments, as inferred from observations at lower redshifts.

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Horizon-AGN virtual observatory: SED-fitting performance and forecasts for future imaging surveys

  • Laigle, Clotilde;Davidzon, I.;Ilbert, O.;Devriendt, J.;Kashino, D.;Capak, P.;Arnouts, S.;De la Torre, S.;Dubois, Y.;Gozaliasl, G.;Leborgne, D.;McCracken, H.J.;Pichon, C.
    • The Bulletin of The Korean Astronomical Society
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    • v.43 no.2
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    • pp.32.3-32.3
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    • 2018
  • We use the synthetic light-cone from the cosmological hydrodynamical simulation Horizon-AGN to produce a mock photometric galaxy catalogue on the redshift range 0

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LOW ORDER TERMS OF AUTOMORPHISMS OF QUADRIC CR MANIFOLDS

  • Park, Won K.
    • Journal of the Chungcheong Mathematical Society
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    • v.9 no.1
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    • pp.27-60
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    • 1996
  • We compute low order terms of automorphisms of a quadric CR manifold defined by $v^a$ =< $A^az$, z > where there is a real vector ${\kappa}{\in}R^m$ such that $det({\kappa}{\cdot}A){\neq}0$.

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Recognition of Dog Breeds based on Deep Learning using a Random-Label and Web Image Mining (웹 이미지 마이닝과 랜덤 레이블을 이용한 딥러닝 기반 개 품종 인식)

  • Kang, Min-Seok;Hong, Kwang-Seok
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2018.10a
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    • pp.201-202
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    • 2018
  • In this paper, a dog breed image provided by Dataset of existing ImageNet and Oxford-IIIT Pet Image is combined with a dog breed image obtained through data mining on Internet and a random-label is added. this paper introduces to recognize 122 classes of dog breeds and 1 class that is not dog breeds. The recognition rate of dog breeds using both conventional DB and collection DB was improved 1.5% over Top-1 compared to recognition rate of dog breeds using only existing DB. The image recognition rate about non-dog image, was 93% recognition rate in case of 10000 random DBs.

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Comparison of COVID-19 Vaccines Introduced in Korea

  • Lee, Chang-Gun;Lee, Dongsup
    • Biomedical Science Letters
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    • v.28 no.2
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    • pp.67-82
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    • 2022
  • The prevalence of SARS-CoV-2 led to inconsistent public health policies that resulted in COVID-19 containment failure. These factors resulted in increased hospitalization and death. To prevent viral spread and achieve herd immunity, the only safe and effective measure is to provide to vaccinates. Ever since the release of the SARS-CoV-2 nucleotide sequence in January of 2020, research centers and pharmaceutical companies from many countries have developed different types of vaccines including mRNA, recombinant protein, and viral vector vaccines. Prior to initiating vaccinations, phase 3 clinical trials are necessary. However, no vaccine has yet to complete a phase 3 clinical trial. Many products obtained "emergency use authorization" from governmental agencies such as WHO, FDA etc. The Korean government authorized the use of five different vaccines. The viral vector vaccine of Oxford/AstraZeneca and the Janssen showed effectiveness of 76% and 66.9%, respectively. The mRNA vaccine of Pfizer-BioNTech and Moderna showed effectiveness of 95% and 94.1%, respectively. The protein recombinant vaccine of Novavax showed an effectiveness of 90.4%. In this review, we compared the characteristics, production platform, synthesis principles, authorization, protective effects, immune responses, clinical trials and adverse effects of five different vaccines currently used in Korea. Through this review, we conceptualize the importance of selecting the optimal vaccine to prevent the COVID-19 pandemic.

Wilde the "Pervert": Oscar and Transnational (Roman Catholic) Religion

  • McCormack, Jerusha
    • Journal of English Language & Literature
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    • v.60 no.2
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    • pp.211-232
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    • 2014
  • In late Victorian England, a "pervert" meant two things. One meaning designated a person who "turned" or converted from one sect of Christianity to another. In Wilde's time this referred specifically to converts from the established state Church of England to the transnational Roman Catholic Church. The other, newer meaning designated someone who turned from conventional heterosexual relations to a (as yet unnamed) homosexual orientation. In the context of the late Victorian empire, both were considered dangerous. The rising social and political influence of Roman Catholicism appeared threatening as a transnational Church invading a national one. For the Anglican Church of England, this crisis was played out what came to be known as the Oxford Movement, still influential during Wilde's time as a student there from 1874 to 1878. What is interesting in Wilde's life, as in his work, is the way he himself played with the dangerous transgressions inherent in being a "pervert." Sexually, he was converted to same-sex love while still a married man. In terms of religion, he remained fascinated with Catholicism, allegedly converting on his death-bed. But what is provocative is way that Wilde used one "perversion" to play into another: so that in such works as The Picture of Dorian Gray and Salome, his version of a kind of anti-Catholic Catholicism becomes a site of sexual desire, and sexual desire expression for that kind of spirituality, which, as unrequited longing, can ultimately n find no object adequate to its imagination.

Intracellular pH Regulation in Cardiac Myocytes

  • Lee, Chae-Hun;Vaughan-Jones, Richard D.
    • Proceedings of the Korean Biophysical Society Conference
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    • 1999.06a
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    • pp.24-25
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    • 1999
  • Intracellular pH(pH$_{i}$) regulation is very important to regulate the cellular functions of cardiac myocytes such as contractility, signal transduction, ion regulation, cell volume, and energy production etc. The resting pH$_{i}$ was maintained at about 7.07 and strictly regulated within the range of $\pm$0.1.(omitted)ted)

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