546 research outputs found
First-Person Perspectives on Dual Diagnosis Anonymous (DDA): A Qualitative Study
Objective: People dually diagnosed with substance abuse and mental illnesses often feel alienated at traditional 12-step meetings, yet they need the peer support provided by such groups. Dual Diagnosis Anonymous (DDA) is a peer-support program specifically for people with co-occurring disorders, which addresses many of the factors that members find alienating about traditional 12-step groups. This study aimed to elicit first-person perspectives on DDA. Methods: Occupational therapy students conducted 13 focus groups with 106 DDA members in three settings: the community (6 groups, n = 36), correctional facilities (5 groups, n = 53), and the state psychiatric hospital (2 groups, n = 17). Researchers inductively analyzed focus group transcripts to identify prominent themes. Results: The vast majority of participants were between the ages of 18 and 49 (n = 87, 82.1%) and were non-Hispanic/White (n = 82, 77.4%). Most participants had been using substances for more than 10 years and had been diagnosed with a mental illness for more than 10 years. The most common substance of choice among those in the community and corrections setting was multiple substances, while those in the state hospital identified alcohol most often. Bipolar disorder was the most common mental illness diagnosis among participants in the state hospital, but depression and anxiety were the two most common diagnoses in the community and corrections participants. Four primary themes emerged from the qualitative analysis: (1) feeling accepted by others in the group, (2) acceptance within the group of mental illness and substance abuse together, (3) the structure of DDA meetings compared to other 12-step meetings, and (4) a focus on hope and recovery from both illnesses. Conclusions: DDA provides a helpful alternative for individuals who do not feel comfortable at traditional 12-step groups due to their mental illness. Members value the acceptance, understanding, discussion, and hope in DDA meetings
Lessons learnt, and still to learn, in first in human stem cell trials
Developing cellular therapies is not straightforward. This Perspective summarizes the experience of a group of academic stem cell investigators working in different clinical areas and aims to share insight into what we wished we knew before starting. These include (1) choosing the stem cell line and assessing the genome of both the starting and final product, (2) familiarity with GMP manufacturing, reagent validation, and supply chain management, (3) product delivery issues and the additional regulatory challenges, (4) the relationship between clinical trial design and preclinical studies, and (5) the market approval requirements, pathways, and partnerships needed
A Widely-Separated, Highly-Occluded Companion to the Nearby Low-Mass T Tauri Star TWA 30
We report the discovery of TWA 30B, a wide (~3400 AU), co-moving M dwarf
companion to the nearby (~42 pc) young star TWA 30. Companionship is confirmed
from their statistically consistent proper motions and radial velocities, as
well as a chance alignment probability of only 0.08%. Like TWA 30A, the
spectrum of TWA 30B shows signatures of an actively accreting disk (H I and
alkali line emission) and forbidden emission lines tracing outflowing material
([O I], [O II], [O III], [S II], and [N II]). We have also detected [C I]
emission in the optical data, marking the first such detection of this line in
a pre-main sequence star. Negligible radial velocity shifts in the emission
lines relative to the stellar frame of rest (Delta V < 30 km/s) indicate that
the outflows are viewed in the plane of the sky and that the corresponding
circumstellar disk is viewed edge-on. Indeed, TWA 30B appears to be heavily
obscured by its disk, given that it is 5 magnitudes fainter than TWA 30A at
K-band despite having a slightly earlier spectral type (M4 versus M5). The
near-infrared spectrum of TWA 30B also evinces an excess that varies on day
timescales, with colors that follow classical T Tauri tracks as opposed to
variable reddening (as is the case for TWA 30A). Multi-epoch data show this
excess to be well-modeled by a blackbody component with temperatures ranging
from 630 to 880 K and emitting areas that scale inversely with the temperature.
The variable excess may arise from disk structure such as a rim or a warp at
the inner disk edge located at a radial distance of ~3-5 R_sun. As the second
and third closest actively accreting and outflowing stars to the Sun (after TWA
3), TWA 30AB presents an ideal system for detailed study of star and planetary
formation processes at the low-mass end of the hydrogen-burning spectrum.Comment: 34 pages, 6 figures, AJ in press; Replaced Figure 4 with a better
color version, added 3 references and slightly amended Section 3.2.
YSOVAR: Six pre-main-sequence eclipsing binaries in the Orion Nebula Cluster
Eclipsing binaries (EBs) provide critical laboratories for empirically
testing predictions of theoretical models of stellar structure and evolution.
Pre-main-sequence (PMS) EBs are particularly valuable, both due to their rarity
and the highly dynamic nature of PMS evolution, such that a dense grid of PMS
EBs is required to properly calibrate theoretical PMS models. Analyzing
multi-epoch, multi-color light curves for 2400 candidateOrion Nebula Cluster
(ONC) members from our Warm Spitzer Exploration Science Program YSOVAR, we have
identified 12 stars whose light curves show eclipse features. Four of these 12
EBs are previously known. Supplementing our light curves with follow-up optical
and near-infrared spectroscopy, we establish two of the candidates as likely
field EBs lying behind the ONC. We confirm the remaining six candidate systems,
however, as newly identified ONC PMS EBs. These systems increase the number of
known PMS EBs by over 50% and include the highest mass (Theta1 Ori E, for which
we provide a complete set of well-determined parameters including component
masses of 2.807 and 2.797 solar masses) and longest period (ISOY
J053505.71-052354.1, P \sim 20 days) PMS EBs currently known. In two cases
(Theta1 Ori E and ISOY J053526.88-044730.7), enough photometric and
spectroscopic data exist to attempt an orbit solution and derive the system
parameters. For the remaining systems, we combine our data with literature
information to provide a preliminary characterization sufficient to guide
follow-up investigations of these rare, benchmark systems.Comment: Accepted by Ap
The Enigmatic Young Low-Mass Variable TWA 30
TWA 30 is a remarkable young (7+/-3 Myr), low-mass (0.12+/-0.04 Msun),
late-type star (M5+/-1) residing 42+/-2 pc away from the sun in the TW Hydrae
Association. It shows strong outflow spectral signatures such as [S II], [O I],
[O II], [O III], and Mg I], while exhibiting weak Halpha emission (-6.8+/-1.2
Angstroms). Emission lines of [S II] and [O I] are common to T Tauri stars
still residing in their natal molecular clouds, while [O III] and Mg I]
emission lines are incredibly rare in this same population; in the case of TWA
30, these latter lines may arise from new outflow material colliding into older
outflow fronts. The weak Halpha emission and small radial velocity shifts of
line emission relative to the stellar frame of rest (generally <=10 km/s)
suggest that the disk is viewed close to edge-on and that the stellar axis may
be inclined to the disk, similar to the AA Tau system, based on its temporal
changes in emission/absorption line strengths/profiles and variable reddening
(A_V=1.5-9.0). The strong Li absorption (0.61+/-0.13 Angstroms) and common
kinematics with members of the TWA confirm its age and membership to the
association. Given the properties of this system such as its proximity, low
mass, remarkable outflow signatures, variability, and edge-on configuration,
this system is a unique case study at a critical time in disk evolution and
planet-building processes.Comment: ApJ in press, 51 pages, 8 tables, 12 figures; converted to preprint
style since emulateapj version cut off Tables 4-
Evolving, dynamic clustering of spatio/spectro-temporal data in 3D spiking neural network models and a case study on EEG data
Clustering is a fundamental data processing technique. While clustering of static (vector based) data and of fixed window size time series have been well explored, dynamic clustering of spatiotemporal data has been little researched if at all. Especially when patterns of changes (events) in the data across space and time have to be captured and understood. The paper presents novel methods for clustering of spatiotemporal data using the NeuCube spiking neural network (SNN) architecture. Clusters of spatiotemporal data were created and modified on-line in a continuous, incremental way, where spatiotemporal relationships of changes in variables are incrementally learned in a 3D SNN model and the model connectivity and spiking activity are incrementally clustered. Two clustering methods were proposed for SNN, one performed during unsupervised and one—during supervised learning models. Before submitted to the models, the data is encoded as spike trains, a spike representing a change in the variable value (an event). During the unsupervised learning, the cluster centres were predefined by the spatial locations of the input data variables in a 3D SNN model. Then clusters are evolving during the learning, i.e. they are adapted continuously over time reflecting the dynamics of the changes in the data. In the supervised learning, clusters represent the dynamic sequence of neuron spiking activities in a trained SNN model, specific for a particular class of data or for an individual instance. We illustrate the proposed clustering method on a real case study of spatiotemporal EEG data, recorded from three groups of subjects during a cognitive task. The clusters were referred back to the brain data for a better understanding of the data and the processes that generated it. The cluster analysis allowed to discover and understand differences on temporal sequences and spatial involvement of brain regions in response to a cognitive task
YSOVAR: Mid-infrared Variability Among YSOs in the Star Formation Region GGD 12-15
S. J. Wolk, et al., “YSOVAR: Mid-infrared Variability Among YSOs in the Star Formation Region GGD 12-15”, The Astronomical Journal, Vol. 150(5), October 2015. © 2015. The American Astronomical Society. All rights reserved.We present an IR-monitoring survey with the Space Telescope of the star forming region GGD 12-15. Over 1000 objects were monitored including about 350 objects within the central 5 arcminutes which is found to be especially dense in cluster members. The monitoring took place over 38 days and is part of the Young Stellar Object VARiability (YSOVAR) project. The region was also the subject of a contemporaneous 67ks observation. The field includes 119 previously identified pre-main sequence star candidates. X-rays are detected from 164 objects, 90 of which are identified with cluster members. Overall, we find that about half the objects in the central 5 arcminutes are young stellar objects based on a combination of their spectral energy distribution, IR variability and X-ray emission. Most of the stars with IR excess relative to a photosphere show large amplitude (>0.1 mag) mid-IR variability. There are 39 periodic sources, all but one of these is found to be a cluster member. Almost half of the periodic sources do not show IR excesses. Overall, more than 85% of the Class I, flat spectrum, and Class II sources are found to vary. The amplitude of the variability is larger in more embedded young stellar objects. Most of the Class~I/II objects exhibit redder colors in a fainter state, compatible with time-variable extinction. A few become bluer when fainter, which can be explained with significant changes in the structure of the inner disk. A search for changes in the IR due to X-ray events is carried out, but the low number of flares prevented an analysis of the direct impact of X-ray flares on the IR lightcurves. However, we find that X-ray detected Class II sources have longer timescales for change in the mid-IR than a similar set of non-X-ray detected Class IIs.Peer reviewe
Systematic review and meta-analysis of the diagnostic accuracy of ultrasonography for deep vein thrombosis
Background
Ultrasound (US) has largely replaced contrast venography as the definitive diagnostic test for deep vein thrombosis (DVT). We aimed to derive a definitive estimate of the diagnostic accuracy of US for clinically suspected DVT and identify study-level factors that might predict accuracy.
Methods
We undertook a systematic review, meta-analysis and meta-regression of diagnostic cohort studies that compared US to contrast venography in patients with suspected DVT. We searched Medline, EMBASE, CINAHL, Web of Science, Cochrane Database of Systematic Reviews, Cochrane Controlled Trials Register, Database of Reviews of Effectiveness, the ACP Journal Club, and citation lists (1966 to April 2004). Random effects meta-analysis was used to derive pooled estimates of sensitivity and specificity. Random effects meta-regression was used to identify study-level covariates that predicted diagnostic performance.
Results
We identified 100 cohorts comparing US to venography in patients with suspected DVT. Overall sensitivity for proximal DVT (95% confidence interval) was 94.2% (93.2 to 95.0), for distal DVT was 63.5% (59.8 to 67.0), and specificity was 93.8% (93.1 to 94.4). Duplex US had pooled sensitivity of 96.5% (95.1 to 97.6) for proximal DVT, 71.2% (64.6 to 77.2) for distal DVT and specificity of 94.0% (92.8 to 95.1). Triplex US had pooled sensitivity of 96.4% (94.4 to 97.1%) for proximal DVT, 75.2% (67.7 to 81.6) for distal DVT and specificity of 94.3% (92.5 to 95.8). Compression US alone had pooled sensitivity of 93.8 % (92.0 to 95.3%) for proximal DVT, 56.8% (49.0 to 66.4) for distal DVT and specificity of 97.8% (97.0 to 98.4). Sensitivity was higher in more recently published studies and in cohorts with higher prevalence of DVT and more proximal DVT, and was lower in cohorts that reported interpretation by a radiologist. Specificity was higher in cohorts that excluded patients with previous DVT. No studies were identified that compared repeat US to venography in all patients. Repeat US appears to have a positive yield of 1.3%, with 89% of these being confirmed by venography.
Conclusion
Combined colour-doppler US techniques have optimal sensitivity, while compression US has optimal specificity for DVT. However, all estimates are subject to substantial unexplained heterogeneity. The role of repeat scanning is very uncertain and based upon limited data
Dynamical Masses of Young Stars I:Discordant Model Ages of Upper Scorpius
We present the results of a long term orbit monitoring program, using sparse
aperture masking observations taken with NIRC2 on the Keck-II telescope, of
seven G to M-type members of the Upper Scorpius subgroup of the Sco-Cen OB
association. We present astrometry and derived orbital elements of the binary
systems we have monitored, and also determine the age, component masses,
distance and reddening for each system using the orbital solutions and
multi-band photometry, including Hubble Space Telescope photometry, and a
Bayesian fitting procedure. We find that the models can be forced into
agreement with any individual system by assuming an age, but that age is not
consistent across the mass range of our sample. The G-type binary systems in
our sample have model ages of ~11.5 Myr, which is consistent with the latest
age estimates for Upper Scorpius, while the M-type binary systems have
significantly younger model ages of ~7 Myr. Based on our fits, this age
discrepancy in the models corresponds to a luminosity under-prediction of
0.8-0.15 dex, or equivalently an effective temperature over-prediction of
100-300 K for M-type stars at a given premain-sequence age. We also find that
the M-type binary system RXJ 1550.0-2312 has an age (~16 Myr) and distance (~90
pc) indicating that it is either a nearby young binary system or a member of
the Upper-Centaurus-Lupus subgroup with a 57% probability of membership.Comment: 16 pages, 8 figures, 9 tables, accepted for publication in Ap
Plant Diversity Changes during the Postglacial in East Asia: Insights from Forest Refugia on Halla Volcano, Jeju Island
Understanding how past climate changes affected biodiversity is a key issue in contemporary ecology and conservation biology. These diversity changes are, however, difficult to reconstruct from paleoecological sources alone, because macrofossil and pollen records do not provide complete information about species assemblages. Ecologists therefore use information from modern analogues of past communities in order to get a better understanding of past diversity changes. Here we compare plant diversity, species traits and environment between late-glacial Abies, early-Holocene Quercus, and mid-Holocene warm-temperate Carpinus forest refugia on Jeju Island, Korea in order to provide insights into postglacial changes associated with their replacement. Based on detailed study of relict communities, we propose that the late-glacial open-canopy conifer forests in southern part of Korean Peninsula were rich in vascular plants, in particular of heliophilous herbs, whose dramatic decline was caused by the early Holocene invasion of dwarf bamboo into the understory of Quercus forests, followed by mid-Holocene expansion of strongly shading trees such as maple and hornbeam. This diversity loss was partly compensated in the Carpinus forests by an increase in shade-tolerant evergreen trees, shrubs and lianas. However, the pool of these species is much smaller than that of light-demanding herbs, and hence the total species richness is lower, both locally and in the whole area of the Carpinus and Quercus forests. The strongly shading tree species dominating in the hornbeam forests have higher leaf tissue N and P concentrations and smaller leaf dry matter content, which enhances litter decomposition and nutrient cycling and in turn favored the selection of highly competitive species in the shrub layer. This further reduced available light and caused almost complete disappearance of understory herbs, including dwarf bamboo
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