6,057 research outputs found
The Optical Velocity of the Antlia Dwarf Galaxy
We present the results of a VLT observing program carried out in service mode
using FORS1 on ANTU in Long Slit mode to determine the optical velocities of
nearby low surface brightness galaxies. Outlying Local Group galaxies are of
paramount importance in placing constraints the dynamics and thus on both the
age and the total mass of the Local Group. Optical velocities are also
necessary to determine if the observations of HI gas in and around these
systems are the result of gas associated with these galaxies or a chance
superposition with high velocity HI clouds or the Magellanic Stream. The data
were of sufficient signal-to-noise to obtain a reliable result in one of the
galaxies we observed - Antlia - for which we have found an optical
helio-centric radial velocity of 351 15 km/s.Comment: 11 pages, 4 figures, 5 tables MNRAS, in pres
Sleep and inflammation in resilient aging.
Sleep quality is important to health, and increasingly viewed as critical in promoting successful, resilient aging. In this review, the interplay between sleep and mental and physical health is considered with a focus on the role of inflammation as a biological pathway that translates the effects of sleep on risk of depression, pain and chronic disease risk in aging. Given that sleep regulates inflammatory biologic mechanisms with effects on mental and physical health outcomes, the potential of interventions that target sleep to reduce inflammation and promote health in aging is also discussed
Learning to Rank Using Localized Geometric Mean Metrics
Many learning-to-rank (LtR) algorithms focus on query-independent model, in
which query and document do not lie in the same feature space, and the rankers
rely on the feature ensemble about query-document pair instead of the
similarity between query instance and documents. However, existing algorithms
do not consider local structures in query-document feature space, and are
fragile to irrelevant noise features. In this paper, we propose a novel
Riemannian metric learning algorithm to capture the local structures and
develop a robust LtR algorithm. First, we design a concept called \textit{ideal
candidate document} to introduce metric learning algorithm to query-independent
model. Previous metric learning algorithms aiming to find an optimal metric
space are only suitable for query-dependent model, in which query instance and
documents belong to the same feature space and the similarity is directly
computed from the metric space. Then we extend the new and extremely fast
global Geometric Mean Metric Learning (GMML) algorithm to develop a localized
GMML, namely L-GMML. Based on the combination of local learned metrics, we
employ the popular Normalized Discounted Cumulative Gain~(NDCG) scorer and
Weighted Approximate Rank Pairwise (WARP) loss to optimize the \textit{ideal
candidate document} for each query candidate set. Finally, we can quickly
evaluate all candidates via the similarity between the \textit{ideal candidate
document} and other candidates. By leveraging the ability of metric learning
algorithms to describe the complex structural information, our approach gives
us a principled and efficient way to perform LtR tasks. The experiments on
real-world datasets demonstrate that our proposed L-GMML algorithm outperforms
the state-of-the-art metric learning to rank methods and the stylish
query-independent LtR algorithms regarding accuracy and computational
efficiency.Comment: To appear in SIGIR'1
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Mindfulness meditation and improvement in depressive symptoms among Spanish- and English speaking adults: A randomized, controlled, comparative efficacy trial.
ObjectiveLatino immigrants experience acculturative stress and increased depression risk. Mindfulness meditation improves depressive symptoms, yet the vast majority of research has focused on English speaking populations.MethodsIn this randomized clinical trial with 2 parallel treatment groups, adults with moderate levels of perceived stress (n = 76) were recruited from the Los Angeles community from October 2015 to March 2016, stratified into Spanish- (n = 36) and English speaking (n = 40) language groups, and randomized for 6 weeks of treatment with standardized mindful awareness practices (MAPs) or health education (HE). Main outcome measure was depressive symptoms, measured by the Beck Depression Inventory.ResultsUsing an intent-to-treat analysis, the primary outcome, depressive symptoms as indexed by the Beck Depression Inventory, showed greater improvement in MAPs vs. HE, with a between-group post-intervention mean difference of -2.2 (95% CI -4.4 - -0.07) and effect size of 0.28; similar effect sizes were found in the the Spanish- (0.29) and English speaking (0.30) groups. MAPs showed significant improvement relative to HE on secondary outcome of mindfulness with between group difference of 10.7 (95% CI4.5-16.9), but not perceived stress.ConclusionThe comparable efficacy of Spanish and English formats of mindfulness meditation in improving depressive symptoms suggests that this community based intervention may mitigate depression risk in Latino adults who are experiencing social adversity.Trial registrationClinicalTrials.gov NCT03545074
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