518 research outputs found
Effectiveness of the ADEC as a level 2 screening test for young children with suspected autism spectrum disorders in a clinical setting
Background The Autism Detection in Early Childhood (ADEC) is a clinician-administered, Level 2 screening tool. A retrospective file audit was used to investigate its clinical effectiveness.
Method Toddlers referred to an Australian child development service between 2008 and 2010 (N?=?53, M age?=?32.2 months) were screened with the ADEC. Their medical records were reviewed in 2013 when their mean age was 74.5 months, and the original ADEC screening results were compared with later diagnostic outcomes.
Results The ADEC had good sensitivity (87.5%) and moderate specificity (62%). Three behaviours predicted autism spectrum disorders (ASDs): response to name, gaze switching, and gaze monitoring (p???.001).
Conclusions The ADEC shows promise as a screening tool that can discriminate between young children with ASDs and those who have specific communication disorders or developmental delays that persist into middle childhood but who do not meet the criteria for ASDs
The Continuing Search to Find a More Effective and Less Intimidating Way to Teach Research Methods in Higher Education
Existing literature examining the teaching of research methods highlights difficulties students face when developing research competencies. Studies of student-centered teaching approaches have found increased student performance and improved confidence in undertaking research projects. To develop a student-centered approach, it could be beneficial to teach students through active participation, with the development of their research agendas as the basis for progression. To develop this goal, the research methods module for graduate students at a UK business school was restructured into a two-week block utilizing a student-centered approach. The performance of the students was then compared to the performance of students who undertook the same course material presented in a traditional semester-long module and the results were then statistically analyzed. The results of this study provide new and interesting evidence of increased student achievement and understanding through the new format and provide new avenues for future research
Erasmus Language students in a British University – a case study
Students’ assessment of their academic experience is actively sought by Higher Education institutions, as evidenced in the National Student Survey introduced in 2005. Erasmus students, despite their growing numbers, tend to be excluded from these satisfaction surveys, even though they, too, are primary customers of a University. This study aims to present results from bespoke questionnaires and semi-structured interviews with a sample of Erasmus students studying languages in a British University. These methods allow us insight into the experience of these students and their assessment as a primary customer, with a focus on language learning and teaching, university facilities and student support. It investigates to what extent these factors influence their levels of satisfaction and what costs of adaptation if any, they encounter. Although excellent levels of satisfaction were found, some costs affect their experience. They relate to difficulties in adapting to a learning methodology based on a low number of hours and independent learning and to a guidance and support system seen as too stifling. The results portray this cohort’s British University as a well-equipped and well-meaning but ultimately overbearing institution, which may indicate that minimising costs can eliminate some sources of dissatisfaction
Broadband Meter-Wavelength Observations of Ionospheric Scintillation
Intensity scintillations of cosmic radio sources are used to study
astrophysical plasmas like the ionosphere, the solar wind, and the interstellar
medium. Normally these observations are relatively narrow band. With Low
Frequency Array (LOFAR) technology at the Kilpisj\"arvi Atmospheric Imaging
Receiver Array (KAIRA) station in northern Finland we have observed
scintillations over a 3 octave bandwidth. ``Parabolic arcs'', which were
discovered in interstellar scintillations of pulsars, can provide precise
estimates of the distance and velocity of the scattering plasma. Here we report
the first observations of such arcs in the ionosphere and the first broad-band
observations of arcs anywhere, raising hopes that study of the phenomenon may
similarly improve the analysis of ionospheric scintillations. These
observations were made of the strong natural radio source Cygnus-A and covered
the entire 30-250\,MHz band of KAIRA. Well-defined parabolic arcs were seen
early in the observations, before transit, and disappeared after transit
although scintillations continued to be obvious during the entire observation.
We show that this can be attributed to the structure of Cygnus-A. Initial
results from modeling these scintillation arcs are consistent with simultaneous
ionospheric soundings taken with other instruments, and indicate that
scattering is most likely to be associated more with the topside ionosphere
than the F-region peak altitude. Further modeling and possible extension to
interferometric observations, using international LOFAR stations, are
discussed.Comment: 11 pages, 17 figure
Results from a Low-Energy Analysis of the CDMS II Germanium Data
We report results from a reanalysis of data from the Cryogenic Dark Matter
Search (CDMS II) experiment at the Soudan Underground Laboratory. Data taken
between October 2006 and September 2008 using eight germanium detectors are
reanalyzed with a lowered, 2 keV recoil-energy threshold, to give increased
sensitivity to interactions from Weakly Interacting Massive Particles (WIMPs)
with masses below ~10 GeV/c^2. This analysis provides stronger constraints than
previous CDMS II results for WIMP masses below 9 GeV/c^2 and excludes parameter
space associated with possible low-mass WIMP signals from the DAMA/LIBRA and
CoGeNT experiments.Comment: 9 pages, 8 figures. Supplemental material included as ancillary
files. v3) Added appendix with additional details regarding energy scale and
background
LOFAR tied-array imaging and spectroscopy of solar S bursts
Context. The Sun is an active source of radio emission that is often associated with energetic phenomena ranging from nanoflares to coronal mass ejections (CMEs). At low radio frequencies (<100 MHz), numerous millisecond duration radio bursts have been reported, such as radio spikes or solar S bursts (where S stands for short). To date, these have neither been studied extensively nor imaged because of the instrumental limitations of previous radio telescopes.
Aims. Here, LOw Frequency ARray (LOFAR) observations were used to study the spectral and spatial characteristics of a multitude of S bursts, as well as their origin and possible emission mechanisms.
Methods. We used 170 simultaneous tied-array beams for spectroscopy and imaging of S bursts. Since S bursts have short timescales and fine frequency structures, high cadence (~50 ms) tied-array images were used instead of standard interferometric imaging, that is currently limited to one image per second.
Results. On 9 July 2013, over 3000 S bursts were observed over a time period of ~8 h. S bursts were found to appear as groups of short-lived (<1 s) and narrow-bandwidth (~2.5 MHz) features, the majority drifting at ~3.5 MHz s-1 and a wide range of circular polarisation degrees (2−8 times more polarised than the accompanying Type III bursts). Extrapolation of the photospheric magnetic field using the potential field source surface (PFSS) model suggests that S bursts are associated with a trans-equatorial loop system that connects an active region in the southern hemisphere to a bipolar region of plage in the northern hemisphere.
Conclusions. We have identified polarised, short-lived solar radio bursts that have never been imaged before. They are observed at a height and frequency range where plasma emission is the dominant emission mechanism, however, they possess some of the characteristics of electron-cyclotron maser emission
LOFAR Sparse Image Reconstruction
Context. The LOw Frequency ARray (LOFAR) radio telescope is a giant digital
phased array interferometer with multiple antennas distributed in Europe. It
provides discrete sets of Fourier components of the sky brightness. Recovering
the original brightness distribution with aperture synthesis forms an inverse
problem that can be solved by various deconvolution and minimization methods
Aims. Recent papers have established a clear link between the discrete nature
of radio interferometry measurement and the "compressed sensing" (CS) theory,
which supports sparse reconstruction methods to form an image from the measured
visibilities. Empowered by proximal theory, CS offers a sound framework for
efficient global minimization and sparse data representation using fast
algorithms. Combined with instrumental direction-dependent effects (DDE) in the
scope of a real instrument, we developed and validated a new method based on
this framework Methods. We implemented a sparse reconstruction method in the
standard LOFAR imaging tool and compared the photometric and resolution
performance of this new imager with that of CLEAN-based methods (CLEAN and
MS-CLEAN) with simulated and real LOFAR data Results. We show that i) sparse
reconstruction performs as well as CLEAN in recovering the flux of point
sources; ii) performs much better on extended objects (the root mean square
error is reduced by a factor of up to 10); and iii) provides a solution with an
effective angular resolution 2-3 times better than the CLEAN images.
Conclusions. Sparse recovery gives a correct photometry on high dynamic and
wide-field images and improved realistic structures of extended sources (of
simulated and real LOFAR datasets). This sparse reconstruction method is
compatible with modern interferometric imagers that handle DDE corrections (A-
and W-projections) required for current and future instruments such as LOFAR
and SKAComment: Published in A&A, 19 pages, 9 figure
CDMSlite: A Search for Low-Mass WIMPs using Voltage-Assisted Calorimetric Ionization Detection in the SuperCDMS Experiment
SuperCDMS is an experiment designed to directly detect Weakly Interacting
Massive Particles (WIMPs), a favored candidate for dark matter ubiquitous in
the Universe. In this paper, we present WIMP-search results using a
calorimetric technique we call CDMSlite, which relies on voltage- assisted
Luke-Neganov amplification of the ionization energy deposited by particle
interactions. The data were collected with a single 0.6 kg germanium detector
running for 10 live days at the Soudan Underground Laboratory. A low energy
threshold of 170 eVee (electron equivalent) was obtained, which allows us to
constrain new WIMP-nucleon spin-independent parameter space for WIMP masses
below 6 GeV/c2.Comment: 7 pages, 4 figure
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