6,421 research outputs found
The BSL Sentence Reproduction Test: Exploring age of acquisition effects in British deaf adults
Here we present initial findings from a BSL sentence reproduction test, adapted from a test originally created for ASL (Hauser et al., 2008), with the aim of creating a screen that can be used to distinguish signers with native-like vs. non-native-like skills. The stimulus items, based on a set of 49 sentences from Hauser et al. (2008), included 40 BSL sentences varying in length and complexity, presented on video by a deaf native BSL signer. Participants were instructed to copy the signed sentence to camera, exactly as they saw it, regardless of phonological or lexical variants for the same concepts that they might prefer. Participants were 20 deaf adults: 10 deaf native signers, 5 deaf early learners first exposed to BSL between ages 2 and 6, and 5 late learners first exposed to BSL at age 11 or later. Responses were scored by a team of deaf and hearing sign language researchers. Responses which were agreed by all scorers as identical to the stimulus were given a score of 1; responses which included any phonological, morphological, lexical or syntactic deviations were given a score of 0 (except for a few specific, agreed-upon acceptable deviations). Results indicate that native signers scored significantly higher than non-native signers. For non-native signers there was no significant differences between early and late learners. We explore implications of these findings for use of the BSL-SRT as a screening test for assessing fluency in deaf adults and for exploring age-of-acquisition effects more generally. Hauser, P., Paludneviciene, R., Supalla, T., & Bavelier, D. (2008). American Sign Language – Sentence Reproduction Test: Development & Implications. In R. M. d. Quadros (Ed.), Sign Languages: Spinning and Unraveling the Past, Present and Future. TISLR 9, Forty-five Papers and Three Posters from the 9th Theoretical Issues in Sign Language Research Conference (pp. 155-167). Petrópolis/RJ. Brazil: Editora Arara Azul
Using conversational data to determine lexical frequency in British Sign Language: The influence of text type
This paper presents findings from an objective lexical frequency study in British Sign Language (BSL) based on 24,823 tokens collected as part of the BSL Corpus Project. The BSL study is only the fourth objective frequency study involving sign languages to be reported and is also the first study for any sign language to be based on entirely on spontaneous conversational data. When compared to previous frequency studies (both spoken and signed), some similarities can be observed although differences that may be attributed to text type are also recorded. When compared with subjective frequency ratings collected for BSL, a positive relationship is reported (similar to what has been observed for spoken languages). This is in contrast to a previous study which suggested a much weaker relationship between the two; however, this conclusion was based on a frequency count derived from narratives. These differences highlight the importance of using frequency measures derived from natural and spontaneous data, an opinion that has been emphasised in the spoken language literature
Interference effects in two-photon ATI by multiple orders high harmonics with random or locked phases
We numerically study 2-photon processes using a set of harmonics from a
Ti:Sapphire laser and in particular interference effects in the Above Threshold
Ionization spectra. We compare the situation where the harmonic phases are
assumed locked to the case where they have a random distribution. Suggestions
for possible experiments, using realistic parameters are discussed.Comment: 11 pages, 13 figures, LaTe
Time-dependent calculation of ionization in Potassium at mid-infrared wavelengths
We study the dynamics of the Potassium atom in the mid-infrared, high
intensity, short laser pulse regime. We ascertain numerical convergence by
comparing the results obtained by the direct expansion of the time-dependent
Schroedinger equation onto B-Splines, to those obtained by the eigenbasis
expansion method. We present ionization curves in the 12-, 13-, and 14-photon
ionization range for Potassium. The ionization curve of a scaled system, namely
Hydrogen starting from the 2s, is compared to the 12-photon results. In the
13-photon regime, a dynamic resonance is found and analyzed in some detail. The
results for all wavelengths and intensities, including Hydrogen, display a
clear plateau in the peak-heights of the low energy part of the Above Threshold
Ionization (ATI) spectrum, which scales with the ponderomotive energy Up, and
extends to 2.8 +- 0.5 Up.Comment: 15 two-column pages with 15 figures, 3 tables. Accepted for
publication in Phys. Rev A. Improved figures, language and punctuation, and
made minor corrections. We also added a comparison to the ADK theor
Mid-J CO Emission in Nearby Seyfert Galaxies
We study for the first time the complete sub-millimeter spectra (450 GHz to
1550 GHz) of a sample of nearby active galaxies observed with the SPIRE Fourier
Transform Spectrometer (SPIRE/FTS) onboard Herschel. The CO ladder (from Jup =
4 to 12) is the most prominent spectral feature in this range. These CO lines
probe warm molecular gas that can be heated by ultraviolet photons, shocks, or
X-rays originated in the active galactic nucleus or in young star-forming
regions. In these proceedings we investigate the physical origin of the CO
emission using the averaged CO spectral line energy distribution (SLED) of six
Seyfert galaxies. We use a radiative transfer model assuming an isothermal
homogeneous medium to estimate the molecular gas conditions. We also compare
this CO SLED with the predictions of photon and X-ray dominated region (PDR and
XDR) models.Comment: Proceedings of the Torus Workshop 2012 held at the University of
Texas at San Antonio, 5-7 December 2012. C. Packham, R. Mason, and A.
Alonso-Herrero (eds.); 6 pages, 3 figure
Full-disc CO(1-0) mapping across nearby galaxies of the EMPIRE survey and the CO-to-H conversion factor
Carbon monoxide (CO) provides crucial information about the molecular gas
properties of galaxies. While CO has been targeted extensively,
isotopologues such as CO have the advantage of being less optically
thick and observations have recently become accessible across full galaxy
discs. We present a comprehensive new dataset of CO(1-0) observations
with the IRAM 30-m telescope of the full discs of 9 nearby spiral galaxies from
the EMPIRE survey at a spatial resolution of 1.5kpc. CO(1-0) is
mapped out to and detected at high signal-to-noise throughout our
maps. We analyse the CO(1-0)-to-CO(1-0) ratio () as a
function of galactocentric radius and other parameters such as the
CO(2-1)-to-CO(1-0) intensity ratio, the 70-to-160m flux
density ratio, the star-formation rate surface density, the star-formation
efficiency, and the CO-to-H conversion factor. We find that varies by
a factor of 2 at most within and amongst galaxies, with a median value of 11
and larger variations in the galaxy centres than in the discs. We argue that
optical depth effects, most likely due to changes in the mixture of
diffuse/dense gas, are favored explanations for the observed variations,
while abundance changes may also be at play. We calculate a spatially-resolved
CO(1-0)-to-H conversion factor and find an average value of
cm (K.km/s) over our sample with a standard
deviation of a factor of 2. We find that CO(1-0) does not appear to be a
good predictor of the bulk molecular gas mass in normal galaxy discs due to the
presence of a large diffuse phase, but it may be a better tracer of the mass
than CO(1-0) in the galaxy centres where the fraction of dense gas is
larger.Comment: accepted for publication in MNRA
Insights into gas heating and cooling in the disc of NGC 891 from Herschel far-infrared spectroscopy
We present Herschel PACS and SPIRE spectroscopy of the most important
far-infrared cooling lines in the nearby edge-on spiral galaxy, NGC 891: [CII]
158 m, [NII] 122, 205 m, [OI] 63, 145 m, and [OIII] 88 m.
We find that the photoelectric heating efficiency of the gas, traced via the
([CII]+[OII]63)/ ratio, varies from a mean of
3.510 in the centre up to 810 at increasing
radial and vertical distances in the disc. A decrease in
([CII]+[OII]63)/ but constant
([CII]+[OI]63)/ with increasing FIR colour suggests that
polycyclic aromatic hydrocarbons (PAHs) may become important for gas heating in
the central regions. We compare the observed flux of the FIR cooling lines and
total IR emission with the predicted flux from a PDR model to determine the gas
density, surface temperature and the strength of the incident far-ultraviolet
(FUV) radiation field, . Resolving details on physical scales of ~0.6
kpc, a pixel-by-pixel analysis reveals that the majority of the PDRs in NGC
891's disc have hydrogen densities of 1 < log (/cm) < 3.5
experiencing an incident FUV radiation field with strengths of 1.7 < log
< 3. Although these values we derive for most of the disc are consistent with
the gas properties found in PDRs in the spiral arms and inter-arm regions of
M51, observed radial trends in and are shown to be sensitive to
varying optical thickness in the lines, demonstrating the importance of
accurately accounting for optical depth effects when interpreting observations
of high inclination systems. With an empirical relationship between the MIPS 24
m and [NII] 205 m emission, we estimate an enhancement of the FUV
radiation field strength in the far north-eastern side of the disc.Comment: Accepted for publication in A&A. 25 pages, including 17 figures and 3
tables, abstract abridged for arXi
Adaptation of a Vocabulary Test from British Sign Language to American Sign Language
This study describes the adaptation process of a vocabulary knowledge test for British Sign Language (BSL) into American Sign Language (ASL) and presents results from the first round of pilot testing with twenty deaf native ASL signers. The web-based test assesses the strength of deaf children’s vocabulary knowledge by means of different mappings of phonological form and meaning of signs. The adaptation from BSL to ASL involved nine stages, which included forming a panel of deaf/hearing experts, developing a set of new items and revising/replacing items considered ineffective, and piloting the new version. Results provide new evidence in support of the use of this methodology for assessing sign language, making a useful contribution toward the availability of tests to assess deaf children’s signed
language skills
Two--Electron Atoms in Short Intense Laser Pulses
We discuss a method of solving the time dependent Schrodinger equation for
atoms with two active electrons in a strong laser field, which we used in a
previous paper [A. Scrinzi and B. Piraux, Phys. Rev. A 56, R13 (1997)] to
calculate ionization, double excitation and harmonic generation in Helium by
short laser pulses. The method employs complex scaling and an expansion in an
explicitly correlated basis. Convergence of the calculations is documented and
error estimates are provided. The results for Helium at peak intensities up to
10^15 W/cm^2 and wave length 248 nm are accurate to at least 10 %. Similarly
accurate calculations are presented for electron detachment and double
excitation of the negative hydrogen ion.Comment: 14 pages, including figure
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