264 research outputs found
Evaluation Framework for Understanding Sensitive Attribute Association Bias in Latent Factor Recommendation Algorithms
We present a novel evaluation framework for representation bias in latent
factor recommendation (LFR) algorithms. Our framework introduces the concept of
attribute association bias in recommendations allowing practitioners to explore
how recommendation systems can introduce or amplify stakeholder representation
harm. Attribute association bias (AAB) occurs when sensitive attributes become
semantically captured or entangled in the trained recommendation latent space.
This bias can result in the recommender reinforcing harmful stereotypes, which
may result in downstream representation harms to system consumer and provider
stakeholders. LFR models are at risk of experiencing AAB due to their ability
to entangle explicit and implicit attributes into the trained latent space.
Understanding this phenomenon is essential due to the increasingly common use
of entity vectors as attributes in downstream components in hybrid industry
recommendation systems. We provide practitioners with a framework for executing
disaggregated evaluations of AAB within broader algorithmic auditing
frameworks. Inspired by research in natural language processing (NLP) observing
gender bias in word embeddings, our framework introduces AAB evaluation methods
specifically for recommendation entity vectors. We present four evaluation
strategies for sensitive AAB in LFR models: attribute bias directions,
attribute association bias metrics, classification for explaining bias, and
latent space visualization. We demonstrate the utility of our framework by
evaluating user gender AAB regarding podcast genres with an industry case study
of a production-level DNN recommendation model. We uncover significant levels
of user gender AAB when user gender is used and removed as a model feature
during training, pointing to the potential for systematic bias in LFR model
outputs
Parsing with Multilingual BERT, a Small Corpus, and a Small Treebank
Pretrained multilingual contextual representations have shown great success,
but due to the limits of their pretraining data, their benefits do not apply
equally to all language varieties. This presents a challenge for language
varieties unfamiliar to these models, whose labeled \emph{and unlabeled} data
is too limited to train a monolingual model effectively. We propose the use of
additional language-specific pretraining and vocabulary augmentation to adapt
multilingual models to low-resource settings. Using dependency parsing of four
diverse low-resource language varieties as a case study, we show that these
methods significantly improve performance over baselines, especially in the
lowest-resource cases, and demonstrate the importance of the relationship
between such models' pretraining data and target language varieties.Comment: In Findings of EMNLP 202
KOI 1224, a Fourth Bloated Hot White Dwarf Companion Found With Kepler
We present an analysis and interpretation of the Kepler binary system KOI
1224. This is the fourth binary found with Kepler that consists of a thermally
bloated, hot white dwarf in a close orbit with a more or less normal star of
spectral class A or F. As we show, KOI 1224 contains a white dwarf with Teff =
14400 +/- 1100 K, mass = 0.20 +/- 0.02 Msun, and radius = 0.103 +/- 0.004 Rsun,
and an F-star companion of mass = 1.59 +/- 0.07 Msun that is somewhat beyond
its terminal-age main sequence. The orbital period is quite short at 2.69802
days. The ingredients that are used in the analysis are the Kepler binary light
curve, including the detection of the Doppler boosting effect; the NUV and FUV
fluxes from the Galex images of this object; an estimate of the spectral type
of the F-star companion; and evolutionary models of the companion designed to
match its effective temperature and mean density. The light curve is modelled
with a new code named Icarus which we describe in detail. Its features include
the full treatment of orbital phase-resolved spectroscopy, Doppler boosting,
irradiation effects and transits/eclipses, which are particularly suited to
irradiated eclipsing binaries. We interpret the KOI 1224 system in terms of its
likely evolutionary history. We infer that this type of system, containing a
bloated hot white dwarf, is the direct descendant of an Algol-type binary. In
spite of this basic understanding of the origin of KOI 1224, we discuss a
number of problems associated with producing this type of system with this
short of an short orbital period.Comment: 14 pages, 8 figures, 2 tables, submitted to Ap
CD94-NKG2A recognition of human leukocyte antigen (HLA)-E bound to an HLA class I leader sequence
The recognition of human leukocyte antigen (HLA)-E by the heterodimeric CD94-NKG2 natural killer (NK) receptor family is a central innate mechanism by which NK cells monitor the expression of other HLA molecules, yet the structural basis of this highly specific interaction is unclear. Here, we describe the crystal structure of CD94-NKG2A in complex with HLA-E bound to a peptide derived from the leader sequence of HLA-G. The CD94 subunit dominated the interaction with HLA-E, whereas the NKG2A subunit was more peripheral to the interface. Moreover, the invariant CD94 subunit dominated the peptide-mediated contacts, albeit with poor surface and chemical complementarity. This unusual binding mode was consistent with mutagenesis data at the CD94-NKG2A–HLA-E interface. There were few conformational changes in either CD94-NKG2A or HLA-E upon ligation, and such a “lock and key” interaction is typical of innate receptor–ligand interactions. Nevertheless, the structure also provided insight into how this interaction can be modulated by subtle changes in the peptide ligand or by the pairing of CD94 with other members of the NKG2 family. Differences in the docking strategies used by the NKG2D and CD94-NKG2A receptors provided a basis for understanding the promiscuous nature of ligand recognition by NKG2D compared with the fidelity of the CD94-NKG2 receptors
WASP-42 b and WASP-49 b: two new transiting sub-Jupiters
We report the discovery of two new transiting planets from the WASP survey.
WASP-42 b is a 0.500 +/- 0.035 M_jup planet orbiting a K1 star at a separation
of 0.0548 +/- 0.0017 AU with a period of 4.9816872 +/- 7.3 x 10^-6 days. The
radius of WASP-42 b is 1.080 +/- 0.057 R_jup while its equilibrium temperature
is T_eq = 995 +/- 34 K. We detect some evidence for a small but non-zero
eccentricity of e=0.060 +/- 0.013. WASP-49 b is a 0.378 +/- 0.027 M_jup planet
around an old G6 star. It has a period of 2.7817387 +/- 5.6 x 10^-6 days and a
separation of 0.0379 +/- 0.0011 AU. This planet is slightly bloated, having a
radius of 1.115 +/- 0.047 R_jup and an equilibrium temperature of T_eq = 1369
+/- 39 K. Both planets have been followed up photometrically, and in total we
have obtained 5 full and one partial transit light curves of WASP-42 and 4 full
and one partial light curves of WASP-49 using the Euler-Swiss, TRAPPIST and
Faulkes South telescopes
Rossiter-McLaughlin Effect Measurements for WASP-16, WASP-25 and WASP-31
We present new measurements of the Rossiter-McLaughlin (RM) effect for three
WASP planetary systems, WASP-16, WASP-25 and WASP-31, from a combined analysis
of their complete sets of photometric and spectroscopic data. We find a low
amplitude RM effect for WASP-16 (Teff = 5700 \pm 150K), suggesting that the
star is a slow rotator and thus of an advanced age, and obtain a projected
alignment angle of lambda = -4.2 degrees +11.0 -13.9. For WASP-25 (Teff =
5750\pm100K) we detect a projected spin-orbit angle of lambda = 14.6 degrees
\pm6.7. WASP-31 (Teff = 6300\pm100K) is found to be well-aligned, with a
projected spin-orbit angle of lambda = 2.8degrees \pm3.1. A circular orbit is
consistent with the data for all three systems, in agreement with their
respective discovery papers. We consider the results for these systems in the
context of the ensemble of RM measurements made to date. We find that whilst
WASP-16 fits the hypothesis of Winn et al. (2010) that 'cool' stars (Teff <
6250K) are preferentially aligned, WASP-31 has little impact on the proposed
trend. We bring the total distribution of the true spin-orbit alignment angle,
psi, up to date, noting that recent results have improved the agreement with
the theory of Fabrycky & Tremaine (2007) at mid-range angles. We also suggest a
new test for judging misalignment using the Bayesian Information Criterion,
according to which WASP-25 b's orbit should be considered to be aligned.Comment: 20 pages, 14 tables, 10 figures. Accepted to MNRA
Ethnomedical survey of plants used by the Orang Asli in Kampung Bawong, Perak, West Malaysia
<p>Abstract</p> <p>Background</p> <p>A qualitative ethnomedical survey was carried out among a local Orang Asli tribe to gather information on the use of medicinal plants in the region of Kampung Bawong, Perak of West Malaysia in order to evaluate the potential medicinal uses of local plants used in curing different diseases and illnesses.</p> <p>Methods</p> <p>Sixteen informants ranging in age from 35 to 65 years were interviewed. A total of 62 species of plants used by Orang Asli are described in this study based on field surveys and direct face to face communication. These plants belonged to 36 families and are used to treat a wide range of discomforts and diseases.</p> <p>Results</p> <p>The results of this study showed that majority of the Orang Asli, of Kampung Bawong are still dependent on local plants as their primary source of medication. As the first ethnomedical study in this area, publishing this work is expected to open up more studies to identify and assess the pharmacological and toxicological action of the plants from this region.</p> <p>Conclusions</p> <p>Preservation and recording of ethnobotanical and ethnomedical uses of traditional medicinal plants is an indispensable obligation for sustaining the medicinal and cultural resource of mankind. Extensive research on such traditional plants is of prime importance to scientifically validate their ethnomedical claims.</p
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