1,392 research outputs found
AX J0049.4-7323 - a close look at a neutron star interacting with a circumstellar disk
Detailed evidence on the system AX J0049.4-7323 is presented here to show how
the passage of the neutron star in the binary system disrupts the circumstellar
disk of the mass donor Be star. A similar effect is noted in three other
Be/X-ray binary systems. Together the observational data should provide
valuable tools for modelling these complex interactions.Comment: 4 pages, accepted for publication in MNRA
A major outburst from the X-ray binary RX J0520.5-6932
We report on the analysis of 8 years of MAssive Compact Halo Objects (MACHO)
data for the source RX J0520.5-6932. A regular period of 24.4 days has been
confirmed, however this is manifest almost entirely in the red part of the
spectrum. A major outburst, lasting approximately 200 days, was observed which
increased the apparent brightness of the object by approximately 0.15
magnitudes without significantly altering its V-R colour index. This outburst
was also seen in X-ray data. The evidence from this analysis points to the
identification of this object as a Be/X-ray binary with a periodically variable
circumstellar disk and a very early optical counterpart.Comment: Paper has been accepted by MNRA
On the periodicities present in the optical light curves of SMC Be/X-ray binaries
We present a comprehensive study of the periodic variations observed in OGLE
I-band light curves of SMC Be/X-ray binaries, discovering new optical
periodicities in 9 systems. We find that these periodicities derive from a
number of mechanisms, notably disturbance of the decretion disk on the orbital
period of the system, and aliased non-radial pulsations. We develop metrics
that allow these mechanisms to be distinguished on the basis of the shape of
the folded optical light curve, and use these metrics to categorise the
periodicities present in \sim 50 SMC binary systems. We conclude that extreme
care must be taken in the interpretation of the OGLE light curves since only
around 30% of the periodicities present can be unambiguously attributed to
orbital periods.Comment: 16 pages, 17 figures, accepted for publication in MNRA
Phonological Iconicity
The arbitrariness of the linguistic sign is a fundamental assumption in modern
linguistic theory. In recent years, however, a growing amount of research has
investigated the nature of non-arbitrary relations between linguistic sounds
and semantics. This review aims at illustrating the amount of findings
obtained so far and to organize and evaluate different lines of research
dedicated to the issue of phonological iconicity. In particular, we summarize
findings on the processing of onomatopoetic expressions, ideophones, and
phonaesthemes, relations between syntactic classes and phonology, as well as
sound-shape and sound-affect correspondences at the level of phonemic
contrasts. Many of these findings have been obtained across a range of
different languages suggesting an internal relation between sublexical units
and attributes as a potentially universal pattern
FUSE Spectra of the Black Hole Binary LMC X-3
Far-ultraviolet spectra of LMC X-3 were taken covering photometric phases
0.47 to 0.74 in the 1.7-day orbital period of the black-hole binary (phase zero
being superior conjunction of the X-ray source). The continuum is faint and
flat, but appears to vary significantly during the observations. Concurrent
RXTE/ASM observations show the system was in its most luminous X-ray state
during the FUSE observations. The FUV spectrum contains strong terrestrial
airglow emission lines, while the only stellar lines clearly present are
emissions from the O VI resonance doublet. Their flux does not change
significantly during the FUSE observations. These lines are modelled as two
asymmetrical profiles, including the local ISM absorptions due to C II and
possibly O VI. Velocity variations of O VI emission are consistent with the
orbital velocity of the black hole and provide a new constraint on its mass.Comment: 12 pages including 1 table, 4 diagrams To appear in A
Exploring Processing of Affective Lexical Semantics in the Visual and Auditory Modalities
While research on affective word processing in adults witnesses increasing
interest, the present paper looks at another group of participants that have
been neglected so far: pupils (age range: 6–12 years). Introducing a variant
of the Berlin Affective Wordlist (BAWL) especially adapted for children of
that age group, the “kidBAWL,” we examined to what extent pupils process
affective lexical semantics similarly to adults. In three experiments using
rating and valence decision tasks in both the visual and auditory modality, it
was established that children show the two ubiquitous phenomena observed in
adults with emotional word material: the asymmetric U-shaped function relating
valence to arousal ratings, and the inversely U-shaped function relating
response times to valence decision latencies. The results for both modalities
show large structural similarities between pupil and adult data (taken from
previous studies) indicating that in the present age range, the affective
lexicon and the dynamic interplay between language and emotion is already
well-developed. Differential effects show that younger children tend to choose
less extreme ratings than older children and that rating latencies decrease
with age. Overall, our study should help to develop more realistic models of
word recognition and reading that include affective processes and offer a
methodology for exploring the roots of pleasant literary experiences and ludic
reading
Orbital Period Determinations for Four SMC Be/X-ray Binaries
We present an optical and X-ray study of four Be/X-ray binaries located in
the Small Magellanic Cloud (SMC). OGLE I-band data of up to 11 years of
semi-continuous monitoring has been analysed for SMC X-2, SXP172 and SXP202B,
providing both a measurement of the orbital period (Porb = 18.62, 68.90, and
229.9 days for the pulsars respectively) and a detailed optical orbital profile
for each pulsar. For SXP172 this has allowed a direct comparison of the optical
and X-ray emission seen through regular RXTE monitoring, revealing that the
X-ray outbursts precede the optical by around 7 days. Recent X-ray studies by
XMM-Newton have identified a new source in the vicinity of SXP15.3 raising
doubt on the identification of the optical counterpart to this X-ray pulsar.
Here we present a discussion of the observations that led to the proposal of
the original counterpart and a detailed optical analysis of the counterpart to
the new X-ray source, identifying a 21.7 d periodicity in the OGLE I-band data.
The optical characteristics of this star are consistent with that of a SMC
Be/X-ray binary. However, this star was rejected as the counterpart to SXP15.3
in previous studies due to the lack of H{\alpha} emission.Comment: Accepted for publication in MNRAS, 11 pages, 17 figure
An Investigation of Be/X-ray Pulsars with OGLE-III Data
We have studied five seasons of OGLE-III data for eight SMC Be/X-ray pulsars
for which no other survey data were available. We have determined orbital
periods for four of these binary systems, one of which also shows nonradial
pulsations. Optical identification of SMC X-2 is reconsidered, but no periods
were found for either of the two possible candidates
Tc-Glutathione Complex (Tc -GSH) : Labelling, Chemical Characterization and Biodistribution in Rats
The chemical structure of 99mTc-GSH has been estabilished using the 99Tc
isotope.
Labeling of glutathione with technetium in the presence of stanous chloride gave a high yield
result. In a comparative study between 99Tc
and 99Tc
glutathione, the Tc-GSH complex obtained
was purified and characterized by uv, visible spectroscopy, HPLC, Biogel chromatography, mass
and NMR spectroscopy. Stoichiometric analysis showed a 2 : 1 molar ratio of GSH/Tc for the
reaction. The molecular mass assessed by mass spectroscopy was 727 Da corresponding to an
oxo(bis) glutathione technetate. NMR studies demonstrated that each glutathione molecule was
coordinated to technetium via cysteinyl sulfur and nitrogen atoms. The biodistribution of the
complex was studied in normal rats. Blood clearance was rapid during the first hour involving a
biexponential curve ( t1/2
(1) : 50 min, t1/2
(2) : 400 min ). No radioactive accumulation was found in
any specific organ except kidney and bladder. All the activity excreted was found unchanged in
urine. In conclusion, Tc-GSH displayed an anionic dimer form as GSH-Tc-GSH. We assume that the
complex is a tetradentate (2N,2S) complex containing a pentavalent technetium coordinated by two
thiol and nitrogen atoms of both GSH ligands, and an apical oxo group
The use of commitment techniques to support weight loss maintenance in obese adolescents
Objectives:
Obesity is a rising problem in adolescents related to unhealthy behaviours. Commitment devises are one type of behavioural intervention that may help people change their behaviours. The current pilot trial tests whether commitment devices delivered via text message help adolescents maintain their recent weight loss.
Methods:
During a 12-week pilot trial adolescents who attended a weight loss camp were randomly assigned to either received text messages that contained only information, i.e., advice, about weight loss management (n=13) or asked for them to commit to following the same advise (n=14).
Results:
The BMI of the adolescents in the commitment group did not change. In contrast, the BMI of adolescents in the information group increased. A linear regression revealed that group was a significant predictor of BMI change. A logistic regression revealed that adolescents in the information group were nearly eight times more likely to regain weight than those in the commitment group.
Conclusions:
This is the first study with adolescents to show weight maintenance using a commitment device. The results suggest that commitment devices can help adolescents maintain their recent weight loss
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