3,056 research outputs found
The Peculiar Chemical Inventory of NGC 2419: an Extreme Outer Halo "Globular Cluster"
NGC 2419 is a massive outer halo Galactic globular cluster (GC) whose stars have previously been shown to have
somewhat peculiar abundance patterns. We have observed seven luminous giants that are members of NGC 2419
with Keck/HIRES at reasonable signal-to-noise ratio. One of these giants is very peculiar, with an extremely low
[Mg/Fe] and high [K/Fe] but normal abundances of most other elements. The abundance pattern does not match
the nucleosynthetic yields of any supernova model. The other six stars show abundance ratios typical of inner halo
Galactic GCs, represented here by a sample of giants in the nearby GC M30. Although our measurements show
that NGC 2419 is unusual in some respects, its bulk properties do not provide compelling evidence for a difference between inner and outer halo GCs
How Do Fairness Definitions Fare? Examining Public Attitudes Towards Algorithmic Definitions of Fairness
What is the best way to define algorithmic fairness? While many definitions
of fairness have been proposed in the computer science literature, there is no
clear agreement over a particular definition. In this work, we investigate
ordinary people's perceptions of three of these fairness definitions. Across
two online experiments, we test which definitions people perceive to be the
fairest in the context of loan decisions, and whether fairness perceptions
change with the addition of sensitive information (i.e., race of the loan
applicants). Overall, one definition (calibrated fairness) tends to be more
preferred than the others, and the results also provide support for the
principle of affirmative action.Comment: To appear at AI Ethics and Society (AIES) 201
Humans need not label more humans: Occlusion Copy & Paste for Occluded Human Instance Segmentation
Modern object detection and instance segmentation networks stumble when
picking out humans in crowded or highly occluded scenes. Yet, these are often
scenarios where we require our detectors to work well. Many works have
approached this problem with model-centric improvements. While they have been
shown to work to some extent, these supervised methods still need sufficient
relevant examples (i.e. occluded humans) during training for the improvements
to be maximised. In our work, we propose a simple yet effective data-centric
approach, Occlusion Copy & Paste, to introduce occluded examples to models
during training - we tailor the general copy & paste augmentation approach to
tackle the difficult problem of same-class occlusion. It improves instance
segmentation performance on occluded scenarios for "free" just by leveraging on
existing large-scale datasets, without additional data or manual labelling
needed. In a principled study, we show whether various proposed add-ons to the
copy & paste augmentation indeed contribute to better performance. Our
Occlusion Copy & Paste augmentation is easily interoperable with any models: by
simply applying it to a recent generic instance segmentation model without
explicit model architectural design to tackle occlusion, we achieve
state-of-the-art instance segmentation performance on the very challenging
OCHuman dataset. Source code is available at
https://github.com/levan92/occlusion-copy-paste.Comment: 13 pages, 5 figures, BMVC 202
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Exploring tourists’ slow food experience: perspectives from slow tourism
This paper aims to explore tourists’ slow food experience from slow tourism perspective, including authenticity, slowness, and environmental consciousness. Data will be collect in March 2021
The Struggle of the Rubiniumite Wars
The Struggle of the Rubiniumite Warsis a browser-based, one- to two-player, simultaneous turn-based strategy game set amongst the stars. It uses WebGL and Three.js for 3D graphics in the browser, Node.js for game engine and artificial intelligence design on the backend, and Socket.io for networking using websockets. The development group’s inspiration, motivation, and reflections are discussed. Additionally, details on the development of the game engine, database integration with Parse, user registration with Nodemailer, graphics with Three.js and HTML/CSS, and audio with HTML5
On slice pretzel links
A link is called slice if it bounds a smooth properly embedded surface
in the 4-ball with no closed components and Euler characteristic 1. If a link
has a single component, then it is slice if and only if it is slice. One
motivation for studying such links is that the double cover of the 3-sphere
branched along a nonzero determinant slice link is a rational homology
3-sphere that bounds a rational homology 4-ball. This article aims to
generalize known results about the sliceness of pretzel knots to the
sliceness of pretzel links. In particular, we completely classify
positive and negative pretzel links that are slice, and obtain partial
classifications of 3-stranded and 4-stranded pretzel links that are
slice. As a consequence, we obtain infinite families of Seifert fiber
spaces that bound rational homology 4-balls
A New Model For Including Galactic Winds in Simulations of Galaxy Formation II: Implementation of PhEW in Cosmological Simulations
Although galactic winds play a critical role in regulating galaxy formation,
hydrodynamic cosmological simulations do not resolve the scales that govern the
interaction between winds and the ambient circumgalactic medium (CGM). We
implement the Physically Evolved Wind (PhEW) model of Huang et al. (2020) in
the GIZMO hydrodynamics code and perform test cosmological simulations with
different choices of model parameters and numerical resolution. PhEW adopts an
explicit subgrid model that treats each wind particle as a collection of clouds
that exchange mass, metals, and momentum with their surroundings and evaporate
by conduction and hydrodynamic instabilities as calibrated on much higher
resolution cloud scale simulations. In contrast to a conventional wind
algorithm, we find that PhEW results are robust to numerical resolution and
implementation details because the small scale interactions are defined by the
model itself. Compared to conventional wind simulations with the same
resolution, our PhEW simulations produce similar galaxy stellar mass functions
at but are in better agreement with low-redshift observations at because PhEW particles shed mass to the CGM before escaping
low mass halos. PhEW radically alters the CGM metal distribution because PhEW
particles disperse metals to the ambient medium as their clouds dissipate,
producing a CGM metallicity distribution that is skewed but unimodal and is
similar between cold and hot gas. While the temperature distributions and
radial profiles of gaseous halos are similar in simulations with PhEW and
conventional winds, these changes in metal distribution will affect their
predicted UV/X-ray properties in absorption and emission.Comment: 23 pages, 17 figures, MNRAS accepte
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