213 research outputs found
Phasic alertness and multisensory integration contribute to visual awareness of weak visual targets in audio-visual stimulation under Continuous Flash Suppression
This work was supported by the Biotechnology and Biological Sciences Research Council(BBSRC) [grant number BB/M010996/1].Peer reviewedPublisher PD
Low availability of carnitine precursors as a possible reason for the diminished plasma carnitine concentrations in pregnant women
<p>Abstract</p> <p>Background</p> <p>It has been shown that plasma carnitine concentrations decrease markedly during gestation. A recent study performed with a low number of subjects suggested that this effect could be due to a low iron status which leads to an impairment of carnitine synthesis. The present study aimed to confirm this finding in a greater number of subjects. It was moreover intended to find out whether low carnitine concentrations during pregnancy could be due to a reduced availability of precursors of carnitine synthesis, namely trimethyllysine (TML) and γ-butyrobetaine (BB).</p> <p>Methods</p> <p>Blood samples of 79 healthy pregnant women collected at delivery were used for this study.</p> <p>Results</p> <p>There was only a weak, non-significant (P > 0.05), correlation between plasma concentration of ferritin and those of free and total carnitine. There was no correlation between other parameters of iron status (plasma iron concentration, hemoglobin, MCV, MCH) and plasma concentration of free and total carnitine. There were, however, significant (P < 0.05) positive correlations between concentrations of TML and BB and those of free and total carnitine in plasma.</p> <p>Conclusions</p> <p>The results of this study suggest that an insufficient iron status is not the reason for low plasma carnitine concentrations observed in pregnant women. It is rather indicated that low plasma carnitine concentrations are caused by a low availability of precursors for carnitine synthesis during gestation.</p
New infrared star clusters in the Northern and Equatorial Milky Way with 2MASS
We carried out a survey of infrared star clusters and stellar groups on the
2MASS J, H and K_s all-sky release Atlas in the Northern and Equatorial Milky
Way (350 < l < 360, 0 < l < 230). The search in this zone complements that in
the Southern Milky Way (Dutra et al. 2003a). The method concentrates efforts on
the directions of known optical and radio nebulae. The present study provides
167 new infrared clusters, stellar groups and candidates. Combining the two
studies for the whole Milky Way, 346 infrared clusters, stellar groups and
candidates were discovered, whereas 315 objects were previously known. They
constitute an important new sample for future detailed studies.Comment: Accepted to Astronomy and Astrophysic
Maximal-intensity exercise does not fully restore muscle pyruvate dehydrogenase complex activation after 3 days of high-fat dietary intake
Background & aims: Exercise activates muscle pyruvate dehydrogenase complex (PDC), but moderate intensity exercise fails to fully activate muscle PDC after high-fat diet [1]. We investigated whether maximal intensity exercise overcomes this inhibition.
Methods: Quadriceps femoris muscle biopsy samples were obtained from healthy males at rest, and after 46 and 92 electrically-evoked maximal intermittent isometric contractions, which were preceded by 3 days of either low- (18%) or high- (69%) isocaloric dietary fat intake (LFD and HFD, respectively).
Results: The ratio of PDCa (active form) to total PDCt (fully activated) at rest was 50% less after HFD (0.32 ± 0.01 vs 0.15 ± 0.01; P<0.05). This ratio increased to 0.77 ± 0.06 after 46 contractions (P<0.001) and to 0.98 ± 0.07 after 92 contractions (P<0.001) in LFD. The corresponding values after HFD were less (0.54 ± 0.06; P<0.01 and 0.70 ± 0.07; P<0.01, respectively). Resting muscle acetyl-CoA and acetylcarnitine content was greater after HFD than LFD (both P<0.05), but their rate of accumulation in the former was reduced during contraction. Muscle lactate content after 92 contractions was 30% greater after HFD (P<0.05). Muscle force generation during contraction was no different between interventions, but HFD lengthened muscle relaxation time (P<0.05). Daily urinary total carnitine excretion after HFD was 2.5-fold greater than after LFD (P<0.01).
Conclusions: A bout of maximal intense exercise did not overcome dietary fat-mediated inhibition of muscle pyruvate dehydrogenase complex activation, and was associated with greater muscle lactate accumulation, as a result of lower PDC flux, and increased muscle relaxation time
Warm dusty discs: Exploring the A star 24um debris population
(Abridged) Studies of debris discs have shown that most systems are analogous
to the EKB. In this study we aim to determine how many IRAS 25um excesses
towards A stars are real, and investigate where the dust lies. We observe with
TIMMI2, VISIR, Michelle and TReCS a sample of A and B-type main sequence stars
reported as having mid-IR excess. We constrain the location of the debris
through combined modelling of the emission spectrum and a modelling technique
designed to constrain the radial extent of emission in mid-IR imaging. We
independently confirm the presence of warm dust around 3 of the candidates:
HD3003, HD80950 and eta Tel. For the binary HD3003 a stability analysis
indicates the dust is either circumstellar and lying at ~4 AU with the binary
orbiting at >14AU, or the dust lies in an unstable location; there is some
evidence for temporal evolution of its excess emission on a ~20 year timescale.
For 7 of the targets we present quantitative limits on the location of dust
around the star. We demonstrate that the disc around HD71155 must have
spatially distinct components at 2 and 60AU. We model the limits of current
instrumentation and show that most of the known A star debris discs which could
be readily resolved at 18um on 8m instruments have been resolved. Limits from
unresolved imaging can help distinguish between competing models of the disc
emission, but resolved imaging is key to the determination of the disc
location. Modelling of the detection limits for extended emission can be useful
for targeting future observational campaigns. MIRI on the JWST will be able to
resolve most of the known A star debris disc population. METIS on the E-ELT
will provide the opportunity to explore the hot disc population more thoroughly
by detecting extended emission where calibration accuracy limits disc detection
through photometry, reaching levels below 1 zodi for stars at <10pc.Comment: Accepted for publication in Astronomy and Astrophysic
Clumpy filaments of the Chamaeleon I cloud: C18O mapping with the SEST
The Chamaeleon I dark cloud (Cha I} has been mapped in C18O J=1-0 with an
angular resolution of 1 arcmin using the SEST telescope. The large scale
structures previously observed with lower spatial resolution in the cloud turn
into a network of clumpy filaments. The automatic Clumpfind routine developed
by Williams et al. 1994 is used to identify individual clumps in a consistent
way. Altogether 71 clumps were found and the total mass of these clumps is 230
Mo. The dense 'cores' detected with the NANTEN telescope (Mizuno et al. 1999)
and the very cold cores detected in the ISOPHOT serendipity survey (Toth et al.
2000) form parts of these filaments but decompose into numerous 'clumps' The
filaments are preferentially oriented at right angles to the large-scale
magnetic field in the region. We discuss the cloud structure, the physical
characteristics of the clumps and the distribution of young stars. The observed
clump mass spectrum is compared with the predictions of the turbulent
fragmentation model of Padoan & Nordlund 2002. An agreement is found if
fragmentation has been driven by very large-scale hypersonic turbulence, and if
it has had time to dissipate into modestly supersonic turbulence in the
interclump gas by the present time.Comment: 15 pages, 11 figures, 1 table, to be published in A&A (Accepted
The mental health of populations directly and indirectly exposed to violent conflict in Indonesia
Background
Large disasters affect people who live both near and far from the areas in which they occur. The mental health impact is expected to be similar to a ripple effect, where the risk of mental health consequences generally decreases with increasing distance from the disaster center. However, we have not been able to identify studies of the ripple effect of man-made disaster on mental health in low-income countries.
Objectives
The objective was to examine the hypothesis of a ripple effect on the mental health consequences in populations exposed to man-made disasters in a developing country context, through a comparison of two different populations living in different proximities from the center of disaster in Mollucas.
Methods
Cross-sectional longitudinal data were collected from 510 Internally Displaced Persons (IDPs) living in Ambon, who were directly exposed to the violence, and non-IDPs living in remote villages in Mollucas, Indonesia, who had never been directly exposed to violence in Mollucas. Data were collected during home visits and statistical comparisons were conducted by using chi square tests, t-test and logistic regression.
Results
There was significantly more psychological distress "caseness" in IDPs than non-IDPs. The mental health consequences of the violent conflict in Ambon supported the ripple effect hypothesis as displacement status appears to be a strong risk factor for distress, both as a main effect and interaction effect. Significantly higher percentages of IDPs experienced traumatic events than non-IDPs in all six event types reported.
Conclusions
This study indicates that the conflict had an impact on mental health and economic conditions far beyond the area where the actual violent events took place, in a diminishing pattern in line with the hypothesis of a ripple effect
New infrared star clusters in the southern Milky Way with 2MASS
We carried out a 2MASS J, H and K_s survey of infrared star clusters in the
Milky Way sector 230 350. This zone was the
least studied in the literature, previously including only 12 infrared clusters
or stellar groups with 10, according to the recent catalogue
by Bica et al. (2003). We concentrated efforts on embedded clusters, which are
those expected in the areas of known radio and optical nebulae. The present
study provides 179 new infrared clusters and stellar groups, which are
interesting targets for detailed future infrared studies. The sample of
catalogued infrared clusters and stellar groups in the Galaxy is now increased
by 63%.Comment: 8 pages, 10 figures, accepted to A&A. Tables 3 and 4 available in
eletronic form at CD
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