130 research outputs found
Neural Mechanisms of Language Development in Infancy
Understanding the neural processes underpinning individual differences in early language development is of increasing interest, as it is known to vary in typical development and to be quite heterogeneous in neurodevelopmental conditions. However, few studies to date have tested whether early brain measures are indicative of the developmental trajectory of language, as opposed to language outcomes at specific ages. We combined recordings from two longitudinal studies, including typically developing infants without a family history of autism, and infants with increased likelihood of developing autism (infant-siblings) (N = 191). Electroencephalograms (EEG) were recorded at 6 months, and behavioral assessments at 6, 12, 18, 24 and 36 months of age. Using a growth curve model, we tested whether absolute EEG spectral power at 6 months was associated with concurrent language abilities, and developmental change in language between 6 and 36 months. We found evidence of an association between 6-month alpha-band power and concurrent, but not developmental change in, expressive language ability in both infant-siblings and control infants. The observed association between 6-month alpha-band power and 6-month expressive language was not moderated by group status, suggesting some continuity in neural mechanisms
Trigonometric Parallaxes of Massive Star-Forming Regions. IX. The Outer Arm in the First Quadrant
We report a trigonometric parallax measurement with the Very Long Baseline
Array for the water maser in the distant high-mass star-forming region
G75.30+1.32. This source has a heliocentric distance of 9.25+-0.45 kpc, which
places it in the Outer arm in the first Galactic quadrant. It lies 200 pc above
the Galactic plane and is associated with a substantial HI enhancement at the
border of a large molecular cloud. At a Galactocentric radius of 10.7 kpc,
G75.30+1.32 is in a region of the Galaxy where the disk is significantly warped
toward the North Galactic Pole. While the star-forming region has an
instantaneous Galactic orbit that is nearly circular, it displays a significant
motion of 18 km/s toward the Galactic plane. The present results, when combined
with two previous maser studies in the Outer arm, yield a pitch angle of about
12 degrees for a large section of the arm extending from the first quadrant to
the third.Comment: 19 pages, 5 figures, 4 tables, accepted by The Astrophysical Journa
Nuclear Disks of Gas and Dust in Early Type Galaxies and the Hunt for Massive Black Holes: Hubble Space Telescope Observations of NGC 6251
We discuss Hubble Space Telescope optical images and spectra of NGC 6251, a
giant E2 galaxy and powerful radio source at a distance of 106 Mpc (for H_0 =
70 km/s/Mpc). The galaxy is known to host a very well defined dust disk (O'Neil
et al. 1994); the exceptional resolution of our V and I images allows a
detailed study of the disk structure. Furthermore, narrow band images centered
on the Halpha+[NII] emission lines, reveal the presence of ionized gas in the
inner 0.3 arcsec of the disk. We used the HST/Faint Object Spectrograph with
the 0.09 arcsec aperture to study the velocity structure of the disk. Dynamical
models were constructed for two extreme (in terms of central concentration)
analytical representations of the stellar surface brightness profile, from
which the mass density and corresponding rotational velocity are derived
assuming a constant mass-to-light ratio (M/L)_V ~ 8.5 M_solar/L_solar. For both
representations of the stellar component, the models show that the gas is in
Keplerian motion around a central mass ~ 4 - 8 X 10^8 solar masses, and that
the contribution of radial flows to the velocity field is negligible.Comment: 45 pages, submitted to Ap
Two rapid assays for screening of patulin biodegradation
ArtĂculo sobre distintos ensayos para comprobar la biodegradaciĂłn de la patulinaThe mycotoxin patulin is produced by the blue
mould pathogen Penicillium expansum in rotting apples
during postharvest storage. Patulin is toxic to a wide range
of organisms, including humans, animals, fungi and bacteria.
Wash water from apple packing and processing
houses often harbours patulin and fungal spores, which can
contaminate the environment. Ubiquitous epiphytic yeasts,
such as Rhodosporidium kratochvilovae strain LS11 which
is a biocontrol agent of P. expansum in apples, have the
capacity to resist the toxicity of patulin and to biodegrade
it. Two non-toxic products are formed. One is desoxypatulinic
acid. The aim of the work was to develop rapid,
high-throughput bioassays for monitoring patulin degradation
in multiple samples. Escherichia coli was highly
sensitive to patulin, but insensitive to desoxypatulinic acid.
This was utilized to develop a detection test for patulin,
replacing time-consuming thin layer chromatography or
high-performance liquid chromatography. Two assays for patulin degradation were developed, one in liquid medium
and the other in semi-solid medium. Both assays allow the
contemporary screening of a large number of samples. The
liquid medium assay utilizes 96-well microtiter plates and
was optimized for using a minimum of patulin. The semisolid
medium assay has the added advantage of slowing
down the biodegradation, which allows the study and isolation
of transient degradation products. The two assays are
complementary and have several areas of utilization, from
screening a bank of microorganisms for biodegradation
ability to the study of biodegradation pathways
[CII] 158 micron line detection of the warm ionized medium in the Scutum--Crux spiral arm tangency
HIFI GOT C+ Galactic plane [CII] spectral survey has detected strong emission
at the spiral arm tangencies. We use the unique viewing geometry of the
Scutum-Crux (S-C) tangency near i = 30degs to detect the warm ionized medium
(WIM) component traced by [CII] and to study the effects of spiral density
waves on Interstellar Medium (ISM) gas. We compare [CII] velocity features with
ancillary HI, 12CO and 13CO data near tangent velocities at each longitude to
separate the cold neutral medium and the warm neutral + ionized components in
the S-C tangency, then we identify [CII] emission at the highest velocities
without any contribution from 12CO clouds, as WIM. We present the GOT C+
results for the S-C tangency. We interpret the diffuse and extended excess
[CII] emission at and above the tangent velocities as arising in the
electron-dominated warm ionized gas in the WIM. We derive an electron density
in the range of 0.2 - 0.9 cm^-3 at each longitude, a factor of several higher
than the average value from Halpha and pulsar dispersion. We interpret the
excess [CII] in S-C tangency as shock compression of the WIM induced by the
spiral density waves.Comment: 5 pages, 3 figures and 1 Tabl
Socio-demographic disparities in receipt of clinical health care services during the COVID-19 pandemic for Canadian children with disability
Background: Little is known about the experience of receiving in-person and virtual clinical health care services during the COVID-19 pandemic for Canadian children with developmental disabilities and delays facing multiple layers of vulnerability (e.g., low income, low educational attainment families). We examined the relationship between socio-demographic factors and the receipt of these services (physical and mental health services) during COVID-19 for Canadian children with these conditions. Methods: Data collected in Canada for the Global Report on Developmental Delays, Disorders and Disabilities were used. The survey: (1) was developed and disseminated in collaboration with caregivers of children with disabilities, (2) included topics such as response to the pandemic and receipt of services and supports, and (3) documented the experiences of a non-random convenience sample of caregivers of children (any age) with these conditions during and prior to the pandemic. We used four logistic regression models to assess the association between socio-demographic factors and receipt of services. Results: Being a single parent, having low educational attainment (high school or less), having low income (making less than $40,000 per year), working less than full time (working part-time, working reduced hours due to COVID, retired, stay home parent or student), as well as male gender and older age of the child with disability were factors associated with decreased likelihood of receiving services. Conclusion: Our findings point to the need for tailoring services for families of children with disabilities, particularly low socioeconomic status families, to ensure continuity of care during public health emergencies
Inefficacy of different strategies to improve guideline awareness – 5-year follow-up of the hypertension evaluation project (HEP)
<p>Abstract</p> <p>Background</p> <p>In spite of numerous guidelines for evidence based diagnostic and therapy adequate knowledge of current recommendations is disappointingly low. In the Hypertension Evaluation Project (HEP I) we showed that awareness of national hypertension guidelines under German practitioners was less than 25% in the year 2000. This indicates the need for efficient strategies to relevantly improve guideline awareness.</p> <p>Methods</p> <p>To asses different tools for amending guideline knowledge we used three strategies (guideline in print, interactive guideline, expert seminars) to train 8325 randomised physicians, who had participated in the HEP I trial. Guideline knowledge of the trained physicians was again tested with the HEP questionnaire and compared to a control group of HEP I physicians.</p> <p>Results</p> <p>The return rate of questionnaires was 57.9% without a significant distinction between the groups. Overall guideline awareness was still low but remarkably improved compared to the results of HEP I (37.1% vs. 23.7%, p < 0.0001). There was no difference between the trained physicians and the control group (35.8% and 35.9% vs. 39.7%, p = n.s.).</p> <p>Conclusion</p> <p>We investigated the influence of different strategies to improve guideline awareness among German physicians. None of our interventions (guideline in print, interactive guideline, expert seminars) brought a notable benefit compared to control group. However, overall knowledge of guideline contents increased from 23.7% to 37.1% over five years. Therefore, other probably multimodal interventions are necessary to significantly improve guideline awareness beyond spontaneous advancement.</p> <p>Trial Registration</p> <p>ISRCTN53383289</p
High-speed, energy-resolved, STJ observations of the AM Her system V2301 Oph
We present high time-resolution optical energy-resolved photometry of the
eclipsing cataclysmic variable V2301 Oph made using the ESA S-Cam detector, an
array of photon counting super-conducting tunnel junction (STJ) devices with
intrinsic energy resolution. Three eclipses were observed, revealing
considerable variation in the eclipse shape, particularly during ingress. The
eclipse shape is shown to be understood in terms of AM Her accretion via a
bright stream, with very little contribution from the white dwarf photosphere
and/or hotspot. About two thirds of the eclipsed light arises in the threading
region. Variation in the extent of the threading region can account for most of
the variations observed between cycles. Spectral fits to the data reveal a
10,000K blackbody continuum with strong, time-varying emission lines of
hydrogen and helium. This is the first time that stellar emission lines have
been detected in the optical band using a non-dispersive photon-counting
system.Comment: Accepted A&
Quasi-periodic oscillations in accreting magnetic white dwarfs II. The asset of numerical modelling for interpreting observations
Magnetic cataclysmic variables are close binary systems containing a strongly
magnetized white dwarf that accretes matter coming from an M-dwarf companion.
High-energy radiation coming from those objects is emitted from the accretion
column close to the white dwarf photosphere at the impact region. Its
properties depend on the characteristics of the white dwarf and an accurate
accretion column model allows the properties of the binary system to be
inferred, such as the white dwarf mass, its magnetic field, and the accretion
rate. We study the temporal and spectral behaviour of the accretion region and
use the tools we developed to accurately connect the simulation results to the
X-ray and optical astronomical observations. The radiation hydrodynamics code
Hades was adapted to simulate this specific accretion phenomena. Classical
approaches were used to model the radiative losses of the two main radiative
processes: bremsstrahlung and cyclotron. The oscillation frequencies and
amplitudes in the X-ray and optical domains are studied to compare those
numerical results to observational ones. Different dimensional formulae were
developed to complete the numerical evaluations. The complete characterization
of the emitting region is described for the two main radiative regimes: when
only the bremsstrahlung losses and when both cyclotron and bremsstrahlung
losses are considered. The effect of the non-linear cooling in- stability
regime on the accretion column behaviour is analysed. Variation in luminosity
on short timescales (~ 1 s quasi-periodic oscillations) is an expected
consequence of this specific dynamic. The importance of secondary shock
instability on the quasi-periodic oscillation phenomenon is discussed. The
stabilization effect of the cyclotron process is confirmed by our numerical
simulations, as well as the power distribution in the various modes of
oscillation.Comment: 13 pages, 13 figures, 2 tables. Accepted for publication in A&
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