3,658 research outputs found
Building an adaptive brain across development: targets for neurorehabilitation must begin in infancy
Much progress has been made toward behavioural and pharmacological intervention in intellectual disability, which was once thought too difficult to treat. Down syndrome research has shown rapid advances, and clinical trials are currently underway, with more on the horizon. Here, we review the literature on the emergent profile of cognitive development in Down syndrome, emphasizing that treatment approaches must consider how some âend stateâ impairments, such as language deficits, may develop from early alterations in neural systems beginning in infancy. Specifically, we highlight evidence suggesting that there are pre- and early postnatal alterations in brain structure and function in Down syndrome, resulting in disturbed network function across development. We stress that these early alterations are likely amplified by Alzheimerâs disease progression and poor sleep. Focusing on three network hubs (prefrontal cortex, hippocampus, and cerebellum), we discuss how these regions may relate to evolving deficits in cognitive function in individuals with Down syndrome, and to their language profile in particular
Executive Control Goes to School: Implications of Preschool Executive Performance for Observed Elementary Classroom Learning Engagement
The transition to elementary school is accompanied by increasing demands for children to regulate their attention and behavior within the classroom setting. Executive control (EC) may be critical for meeting these demands; however, few studies have rigorously examined the association between EC and observed classroom behavior. This study examined EC in preschool (age 5 years, 3 months) as a predictor of classroom learning engagement behaviors in first grade, using a battery of performance-based EC tasks and live classroom observations in a longitudinal sample of 313 children. Multilevel modeling results indicated that stronger EC predicted more focused engagement and fewer task management and competing responses, controlling for socioeconomic status, child sex, and age at observations. Results suggest that early EC may support subsequent classroom engagement behaviors that are critical for successful transition to elementary school and long-term learning trajectories
Does Familial Non-Medullary Thyroid Cancer Adversely Affect Survival?
Background: Familial non-medullary thyroid cancer (FNMTC) is associated with a higher rate of multifocality and a higher recurrence rate than sporadic thyroid cancer. However, the effect of FNMTC on life expectancy is unknown. Material and Methods: Using data from our FNMTC database, we calculated life expectancy and survival rates after diagnosis of FNMTC and compared the results with the rates for unaffected family members and for the standard US population. Overall life expectancy and survival rates were calculated using the Kaplan-Meier method. We compared patients from families with 2 affected members with patients from families with â„3 affected members. We also compared patients diagnosed in a known familial setting (index cases and subsequent cases) with patients diagnosed before the familial setting was recognized. Results: There were 139 affected patients with 757 unaffected family members. The mean age at diagnosis was 40.8 ± 13.9 years and the mean follow-up time was 9.4 ± 11.7 years. Ten patients died of thyroid cancer during follow-up. The life expectancy of patients with FNMTC was similar to that of their unaffected family members. Survival was significantly shorter for patients with 3 or more affected family members, for patients diagnosed before the familial setting was recognized, and for patients with anaplastic cancer. Conclusions: Our results suggest that FNMTC may be more aggressive than sporadic thyroid cancer, particularly in families with 3 or more affected members. However, when recognized and treated appropriately, it does not significantly shorten the overall life expectancy of the affected patient
Promising Findings that the Cultivating Healthy Intentional Mindful Educatorsâ Program (CHIME) Strengthens Early Childhood Teachersâ Emotional Resources: An Iterative Study
Findings suggest that an eight-week mindfulness compassion-based program, Cultivating Healthy Intentional Mindful Educators (CHIME), is a feasible professional development intervention for early childhood (EC) teachers to support their emotion regulation and psychological and workplace well-being. We offer preliminary evidence that learning about mindfulness, self-compassion, and social-emotional learning supports EC teachers in strengthening their knowledge and application of practices to be more mindful and less emotionally reactive and emotionally exhausted at work. In analyzing both EC teacher feedback and survey data from two pilot studies, there was promising evidence that participating in CHIME enhanced awareness of emotions and the development of strategies to manage emotions. As CHIME is further developed and refined it will be integral to have collaborative engagement and participation from EC teachers and programs to ensure that learning these practices are relevant, helpful, meaningful, and sustainable
Dimension- and Context-Specific Expression of Preschoolersâ Disruptive Behaviors Associated with Prenatal Tobacco Exposure
ObjectiveâPrecise phenotypic characterization of prenatal tobacco exposure (PTE) ârelated disruptive behavior (DB) that integrates nuanced measures of both exposures and outcomes is optimal for elucidating underlying mechanisms. Using this approach, our goals were to identify dimensions of DB most sensitive to PTE prior to school entry and assess contextual variation in these dimensions.
MethodsâA community obstetric sample of N=369 women (79.2% lifetime smokers; 70.2% pregnancy smokers) from two Midwestern cities were assessed for PTE using cotinine-calibrated interview-based reports at 16, 28, and 40 weeks of gestation. A subset of n=244 who completed observational assessments with their 5-year-old children in a subsequent preschool follow-up study constitute the analytic sample. Using two developmentally-meaningful dimensions previously associated with emergent clinical risk for DBâirritability and noncomplianceâwe assessed children with 2 parent-report scales: the Multidimensional Assessment Profile of Disruptive Behavior (MAP-DB) and the Early Childhood Inventory (ECI). We also assessed children by direct observation across 3 interactional contexts with the Disruptive Behavior Diagnostic Observation Schedule (DB-DOS). We used generalized linear models to examine between-child variability across behavioral dimensions, and mixed effects models to examine directly observed within-child variability by interactional context.
ResultsâIncreasing PTE predicted increasing impairment in preschoolersâ modulation of negative affect (irritability), but not negative behavior (noncompliance) across reported (MAP-DB) and observed (DB-DOS) dimensional measures. Moreover, childrenâs PTE-related irritability was more pronounced when observed with parents than with the examiner. The ECI did not detect PTE-related irritability nor noncompliance.
ConclusionsâNuanced, dimension- and context-specific characterization of PTE-related DB described can optimize early identification of at-risk children
A search for counterparts to massive X-ray binaries using photometric catalogues
(abridged) INTEGRAL has discovered large numbers of new hard X-ray sources,
many of which are believed to be high mass X-ray binaries. However, for a
significant fraction, their counterparts remain unidentified. We explore the
use of photometric catalogues to find optical counterparts to high mass X-ray
binaries. Candidates were selected from 2MASS photometry by means of a
reddening free Q parameter. Sufficiently bright candidates were
spectroscopically observed. Many of the candidates selected turned out to be
moderately reddened late A or early F stars, but our method is able to identify
the counterpart to IGR J16207-5129, confirmed by a Chandra localisation. We
classify this object as a B0 supergiant. In the field of AX J1820.5-1434, we
find a mid or early B-type star, but we cannot confirm it as the counterpart.
For AX J1700.2-4220, we do not find any suitable candidate within the ASCA
error circle. We classify HD 153295, a marginal candidate to be the
counterpart, as B0.5IVe, and find a distance compatible with membership in Sco
OB1. We derive a spectral type B0IIIe for HD100199, previously identified as
the counterpart to IGR J11305-6256. In the case of IGR J17091-3624, the object
associated with a variable radio source in the field is a late F star. The
procedure used is able to correctly identify OB stars and, in about one third
of the cases, may lead to the localisation of the correct counterpart. However,
the majority of INTEGRAL error circles do not contain any suitable optically
visible counterpart. Deep infrared searches are going to be necessary in order
to locate the counterparts to these sources.Comment: 10 pages, 6 figures; Accepted for publication in Astronomy &
Astrophysics (Sept 25th
Individual variation in undergraduate student metacognitive monitoring and error detection during biology model evaluation
IntroductionModels are a primary mode of science communication and preparing university students to evaluate models will allow students to better construct models and predict phenomena. Model evaluation relies on studentsâ subject-specific knowledge, perception of model characteristics, and confidence in their knowledge structures.MethodsFifty first-year college biology students evaluated models of concepts from varying biology subject areas with and without intentionally introduced errors. Students responded with âerrorâ or âno errorâ and âconfidentâ or ânot confidentâ in their response.ResultsOverall, students accurately evaluated 65% of models and were confident in 67% of their responses. Students were more likely to respond accurately when models were drawn or schematic (as opposed to a box-and-arrow format), when models had no intentional errors, and when they expressed confidence. Subject area did not affect the accuracy of responses.DiscussionVariation in response patterns to specific models reflects variation in model evaluation abilities and suggests ways that pedagogy can support student metacognitive monitoring during model-based reasoning. Error detection is a necessary step towards modeling competence that will facilitate student evaluation of scientific models and support their transition from novice to expert scientists
The population of OB supergiants in the starburst cluster Westerlund 1
Context. After leaving the main sequence, massive stars undergo complex evolution, a process that is still poorly understood. With a population of hundreds of OB stars, the starburst cluster Westerlund 1 offers an unparallelled environment to study their evolutionary tracks.
Aims. We characterise a large sample of evolved OB stars in the cluster, with the aim of determining cluster parameters and place stars in an evolutionary sequence.
Methods. We used the FORS2 instrument on the VLT to obtain intermediate-resolution spectroscopy over the range 5800-9000 Ă
of about a hundred stars selected as likely members of the cluster based on their photometry. We developed criteria for their spectral classification using only spectral features in the range observed. We discuss these criteria, useful for spectral classification of early-type stars in the GAIA spectral region, in the appendix. Using these criteria, we obtain spectral classifications, probably accurate to one subtype, for 57 objects, most of which had no previous classification or a generic classification.
Results. We identify more than 50 objects as OB supergiants. We find almost 30 luminous early-B supergiants and a number of less luminous late-O supergiants. In addition, we find a few mid B supergiants with very high luminosity, some of them displaying signs of heavy mass loss. All these stars form a sequence compatible with theoretical evolutionary tracks. In addition, two early B supergiants also show indication of heavy mass loss and may represent the evolutionary phase immediately prior to the Wolf-Rayet stage. We investigate cluster properties using the spectral types and existing photometry. We find that the reddening law to the cluster does not deviate strongly from standard, even though extinction is quite variable, with an average value AV=10.8. Though evolutionary tracks for high-mass stars are subject to large uncertainties, our data support an age of âł 5 Myr and a distance d â5 kpc for Westerlund 1.
Conclusions. The spectral types observed are compatible with a single burst of star formation (the age range is very unlikely to be >1 Myr). Westerlund 1 shows its potentiality as a laboratory for massive star evolution, which can be fulfilled by detailed study of the population presented here.
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On the massive stellar population of the Super Star Cluster Westerlund 1
We present new spectroscopic and photometric observations of the young
Galactic open cluster Westerlund 1 (Wd 1) that reveal a unique population of
massive evolved stars. We identify ~200 cluster members and present
spectroscopic classifications for ~25% of these. We find that all stars so
classified are unambiguously post-Main Sequence objects, consistent with an
apparent lack of an identifiable Main Sequence in our photometric data to V~20.
We are able to identify rich populations of Wolf Rayet stars, OB supergiants
and short lived transitional objects. Of these, the latter group consists of
both hot (Luminous Blue Variable and extreme B supergiants) and cool (Yellow
Hypergiant and Red Supergiant) objects - we find that half the known Galactic
population of YHGs resides within Wd1. We obtain a mean V-M_V ~25 mag from the
cluster Yellow Hypergiants, implying a Main Sequence turnoff at or below M_V
=-5 (O7 V or later). Based solely on the masses inferred for the 53
spectroscopically classified stars, we determine an absolute minimum mass of
\~1.5 x 10^3 Msun for Wd 1. However, considering the complete photometrically
and spectroscopically selected cluster population and adopting a Kroupa IMF we
infer a likely mass for Wd 1 of ~10^5 Msun, noting that inevitable source
confusion and incompleteness are likely to render this an underestimate. As
such, Wd 1 is the most massive compact young cluster yet identified in the
Local Group, with a mass exceeding that of Galactic Centre clusters such as the
Arches and Quintuplet. Indeed, the luminosity, inferred mass and compact nature
of Wd 1 are comparable with those of Super Star Clusters - previously
identified only in external galaxies - and is consistent with expectations for
a Globular Cluster progenitor.Comment: A&A in press, 24 pages with 19 figures. For full resolution version
see http://www.edpsciences.org/articles/aa/pdf/press-releases/PRAA200506.pdf
(now correct url
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