4,495 research outputs found
Comparing Measures of Linguistic Diversity Across Social Media Language Data and Census Data at Subnational Geographic Areas
This paper describes a preliminary study on the comparative linguistic
ecology of online spaces (i.e., social media language data) and real-world
spaces in Aotearoa New Zealand (i.e., subnational administrative areas). We
compare measures of linguistic diversity between these different spaces and
discuss how social media users align with real-world populations. The results
from the current study suggests that there is potential to use online social
media language data to observe spatial and temporal changes in linguistic
diversity at subnational geographic areas; however, further work is required to
understand how well social media represents real-world behaviour
cantnlp@LT-EDI@RANLP-2023: Homophobia/Transphobia Detection in Social Media Comments using Spatio-Temporally Retrained Language Models
This paper describes our multiclass classification system developed as part
of the LTEDI@RANLP-2023 shared task. We used a BERT-based language model to
detect homophobic and transphobic content in social media comments across five
language conditions: English, Spanish, Hindi, Malayalam, and Tamil. We
retrained a transformer-based crosslanguage pretrained language model,
XLMRoBERTa, with spatially and temporally relevant social media language data.
We also retrained a subset of models with simulated script-mixed social media
language data with varied performance. We developed the best performing
seven-label classification system for Malayalam based on weighted macro
averaged F1 score (ranked first out of six) with variable performance for other
language and class-label conditions. We found the inclusion of this
spatio-temporal data improved the classification performance for all language
and task conditions when compared with the baseline. The results suggests that
transformer-based language classification systems are sensitive to
register-specific and language-specific retraining
The Role of Stress in the Pathogenesis and Maintenance of Obsessive-Compulsive Disorder
Individuals with obsessive-compulsive disorder often identify psychosocial stress as a factor that exacerbates their symptoms, and many trace the onset of symptoms to a stressful period of life or a discrete traumatic incident. However, the pathophysiological relationship between stress and obsessive-compulsive disorder remains poorly characterized: it is unclear whether trauma or stress is an independent cause of obsessive-compulsive disorder symptoms, a triggering factor that interacts with a preexisting diathesis, or simply a nonspecific factor that can exacerbate obsessive-compulsive disorder along with other aspects of psychiatric symptomatology. Nonetheless, preclinical research has demonstrated that stress has conspicuous effects on corticostriatal and limbic circuitry. Specifically, stress can lead to neuronal atrophy in frontal cortices (particularly the medial prefrontal cortex), the dorsomedial striatum (caudate), and the hippocampus. Stress can also result in neuronal hypertrophy in the dorsolateral striatum (putamen) and amygdala. These neurobiological effects mirror reported neural abnormalities in obsessive-compulsive disorder and may contribute to an imbalance between goal-directed and habitual behavior, an imbalance that is implicated in the pathogenesis and expression of obsessive-compulsive disorder symptomatology. The modulation of corticostriatal and limbic circuits by stress and the resultant imbalance between habit and goal-directed learning and behavior offers a framework for investigating how stress may exacerbate or trigger obsessive-compulsive disorder symptomatology
Correlation between the spatial distribution of circumstellar disks and massive stars in the young open cluster NGC 6611. II: Cluster members selected with Spitzer/IRAC
Context: the observations of the proplyds in the Orion Nebula Cluster,
showing clear evidence of ongoing photoevaporation, have provided a clear proof
about the role of the externally induced photoevaporation in the evolution of
circumstellar disks. NGC 6611 is an open cluster suitable to study disk
photoevaporation, thanks to its large population of massive members and of
stars with disk. In a previous work, we obtained evidence of the influence of
the strong UV field generated by the massive cluster members on the evolution
of disks around low-mass Pre-Main Sequence members. That work was based on a
multi-band BVIJHK and X-ray catalog purposely compiled to select the cluster
members with and without disk. Aims: in this paper we complete the list of
candidate cluster members, using data at longer wavelengths obtained with
Spitzer/IRAC, and we revisit the issue of the effects of UV radiation on the
evolution of disks in NGC 6611. Methods: we select the candidate members with
disks of NGC 6611, in a field of view of 33'x34' centered on the cluster, using
IRAC color-color diagrams and suitable reddening-free color indices. Besides,
using the X-ray data to select Class III cluster members, we estimate the disks
frequency vs. the intensity of the incident radiation emitted by massive
members. Results: we identify 458 candidate members with circumstellar disks,
among which 146 had not been revealed in our previous work. Comparing of the
various color indices we used to select the cluster members with disk, we claim
that they detect the excesses due to the emission of the same physical region
of the disk: the inner rim at the dust sublimation radius. Our new results
confirm that UV radiation from massive stars affects the evolution of nearby
circumstellar disks.Comment: Accepted for publication at Astronomy & Astrophysic
Degenerate dispersive equations arising in the study of magma dynamics
An outstanding problem in Earth science is understanding the method of
transport of magma in the Earth's mantle. Models for this process, transport in
a viscously deformable porous media, give rise to scalar degenerate,
dispersive, nonlinear wave equations. We establish a general local
well-posedness for a physical class of data (roughly ) via fixed point
methods. The strategy requires positive lower bounds on the solution. This is
extended to global existence for a subset of possible nonlinearities by making
use of certain conservation laws associated with the equations. Furthermore, we
construct a Lyapunov energy functional, which is locally convex about the
uniform state, and prove (global in time) nonlinear dynamic stability of the
uniform state for any choice of nonlinearity. We compare the dynamics to that
of other problems and discuss open questions concerning a larger range of
nonlinearities, for which we conjecture global existence.Comment: 27 Pages, 7 figures are not present in this version. See
http://www.columbia.edu/~grs2103/ for a PDF with figures. Submitted to
Nonlinearit
Reliability and Criterion Validity of the Assess2Perform Bar Sensei
The Assess2Perform Bar Sensei is a device used to measure barbell velocity for velocity-based training that has not yet been validated. The purpose of this study was to determine criterion validity and reliability of the Assess2Perform Bar Sensei in barbell back squats by comparing it against the GymAware PowerTool, a previously validated instrument. Sixteen injury-free, resistance-trained subjects (eleven males and five females) were recruited. Subjects were tested for their back squat one repetition maximum (1RM). Then, on two separate days, subjects performed two sets of three repetitions at loads of 45%, 60% and 75% 1RM. The GymAware PowerTool and Bar Sensei were attached to the barbell in similar locations for concurrent collection of mean concentric velocity (MCV) and peak concentric velocity (PCV). The Bar Sensei and PowerTool showed generally fair to poor agreement for MCV and PCV when subjects lifted 45% of 1RM (intraclass correlation;ICC 0.4–0.59), and they showed poor agreement when subjects lifted 60% and 75% of 1RM (ICC 0.3–0.4). Inter-repetition/within-set reliability for the Bar Sensei ranged between ICC = 0.273–0.451 for MCV and PCV compared to the far more reliable PowerTool (ICC = 0.651–0.793). Currently, the Bar Sensei is not a reliable or valid tool for measuring barbell velocity in back squats
Embedded Stellar Populations towards Young Massive Star Formation Regions I. G305.2+0.2
We present deep, wide-field J, H and Ks images taken with IRIS2 on the Anglo
Australian Telescope, towards the massive star formation region G305.2+0.2.
Combined with 3.6, 4.5, 5.8 and 8.0 micron data from the GLIMPSE survey on the
Spitzer Space Telescope, we investigate the properties of the embedded stellar
populations. After removing contamination from foreground stars we separate the
sources based on their IR colour. Strong extended emission in the GLIMPSE
images hampers investigation of the most embedded sources towards the known
sites of massive star formation. However, we find a sizeable population of IR
excess sources in the surrounding region free from these completeness effects.
Investigation reveals the recent star formation activity in the region is more
widespread than previously known.
Stellar density plots show the embedded cluster in the region, G305.24+0.204,
is offset from the dust emission. We discuss the effect of this cluster on the
surrounding area and argue it may have played a role in triggering sites of
star formation within the region. Finally, we investigate the distribution of
IR excess sources towards the cluster, in particular their apparent lack
towards the centre compared with its immediate environs.Comment: 16 pages, 16 figures (significantly size reduced), 2 tables, accepted
MNRA
Domain decomposition for implicit solvation models
International audienceThis article is the first of a series of papers dealing with domain decomposition algorithms for implicit solvent models. We show that, in the framework of the COSMO model, with van der Waals molecular cavities and classical charge distributions, the electrostatic energy contribution to the solvation energy, usually computed by solving an integral equation on the whole surface of the molecular cavity, can be computed more efficiently by using an integral equation formulation of Schwarz's domain decomposition method for boundary value problems. In addition, the so-obtained potential energy surface is smooth, which is a critical property to perform geometry optimization and molecular dynamics simulations. The purpose of this first article is to detail the methodology, set up the theoretical foundations of the approach, and study the accuracies and convergence rates of the resulting algorithms. The full efficiency of the method and its applicability to large molecular systems of biological interest is demonstrated elsewhere
Investigating the efficiency limitations of GaN-based emitters
In this study low temperature and high pressure techniques have been used to investigate the recombination processes taking place in InGaN-based quantum well light emitting diodes (LEDs) which have emission across the blue-green region. Despite relatively high peak efficiencies of the GaN-based emitters, there remain issues relating to the strong efficiency reduction at higher currents that are required for normal operation in most applications. It is observed that there is a relative reduction in efficiency as injection current is increased in a phenonmenon which is known as efficiency droop. There are three main arguments for the cause of efficiency droop that are discussed in the literature: non-radiative Auger recombination, carrier leakage and a defect-related loss mechanism. In spite of extensive research to date, there is little agreement on the cause of efficiency droop as most experiments can only measure the overall efficiency behaviour leading to difficulties in determining the individual contributions from the different loss mechanisms
Chronology of star formation and disk evolution in the Eagle Nebula
Massive SFR are characterized by intense ionizing fluxes, strong stellar
winds and supernovae explosions, all of which have important effects on the
surrounding media, on the star-formation (SF) process and on the evolution of
YSOs and their disks. We present a multiband study of the massive young cluster
NGC6611 and M16, to study how OB stars affect the early stellar evolution and
the SF. We search for evidence of triggered SF by OB stars in NGC6611 on a
large spatial scale (~10 pc) and how the efficiency of disks photoevaporation
depends on the central stars mass. We assemble a multiband catalog with
photometric data, from B band to 8.0micron, and X-ray data obtained with 2 new
and 1 archival ACIS-I observation. We select the stars with disks from IR
photometry and disk-less from X-ray emission, both in NGC6611 and the outer
region of M16. We study induced photoevaporation searching for the spatial
variation of disk frequency for distinct stellar mass ranges. The triggering of
SF by OB stars has been investigated by deriving the history of SF across the
nebula. We find evidence of sequential SF in the Eagle Nebula going from the SE
(2.6 Myrs) to the NW (0.3 Myrs), with the median age of ~1 Myear. We observe a
drop of the disk frequency close to OB stars (up to an average distance of 1
pc), without effects at larger distances. Furthermore, disks are more frequent
around low-mass stars (<1 M(solar)) than in high-mass stars, regardless of the
distance from OB stars. The SF chronology in M16 does not support the
hypothesis of a large-scale SF triggered by OB stars in NGC6611. Instead, we
speculate that it was triggered by the encounter (~3 Myrs ago) with a giant
molecular shell created ~6 Myrs ago.Comment: Accepted for publication at Astronomy and Astrophysic
- …