1,762 research outputs found
Transport of positrons in the interstellar medium
This work investigates some aspects of the transport of low-energy positrons
in the interstellar medium (ISM). We consider resonance interactions with
magnetohydrodynamic waves above the resonance threshold. Below the threshold,
collisions take over and deflect positrons in their motion parallel to
magnetic-field lines. Using Monte-Carlo simulations, we model the propagation
and energy losses of positrons in the different phases of the ISM until they
annihilate. We suggest that positrons produced in the disk by an old population
of stars, with initial kinetic energies below 1 MeV, and propagating in the
spiral magnetic field of the disk, can probably not penetrate the Galactic
bulge.Comment: 4 pages, 3 figures, accepted for publication in the proceeding of the
6th INTEGRAL worksho
The effect of nitrogen and phosphorus supply on the competition between Cenchrus buflorus and Alysicarpus ovalifolius
Efficiency of Photodynamic Therapy in the Treatment of Diffuse Facial Viral Warts in an Immunosuppressed Patient: Towards a Gold Standard?
A 64-year-old man with a pulmonary transplant developed diffuse verrucae vulgares of the neck. After the failure of multiple cryotherapy treatments, 3 sessions of photodynamic therapy resulted in rapid therapeutic clinical success. This moderately painful and well-tolerated treatment is reproducible and can be very useful in treating papillomavirus infections in the immunosuppressed patient
Differential expression of GABAA receptor α-subunits in rat brain during development
AbstractUnique cytoplasmic loop regions of the α1, α2, α3 and α5 subunits of the GABAA receptor have been expressed in E. coli and used to generate polyclonal antisera specific for these subunits. The antibodies identify proteins by SDS-polyacrylamide gel electrophoresis and western blotting of molecular size 51 kDa, 53 kDa, 59 kDa and 55 kDa, respectively, which show differential patterns of expression during development. Whereas the α2 and α3 subunits are present at early stages, the expression of α1 and α5 subunits is low at birth and increases with age. This differential expression could be correlated with previous studies examining the developmental expression of BZ1 and BZ2 benzodiazepine binding sites
The all-sky distribution of 511 keV electron-positron annihilation emission
We present a map of 511 keV electron-positron annihilation emission, based on
data accumulated with the SPI spectrometer aboard ESA's INTEGRAL gamma-ray
observatory, that covers approximately 95% of the celestial sphere. 511 keV
line emission is significantly detected towards the galactic bulge region and,
at a very low level, from the galactic disk. The bulge emission is highly
symmetric and is centred on the galactic centre with an extension of 8 deg. The
emission is equally well described by models that represent the stellar bulge
or halo populations. The disk morphology is only weakly constrained by the
present data, being compatible with both the distribution of young and old
stellar populations. The 511 keV line flux from the bulge and disk components
is 1.05e-3 ph cm-2 s-1 and 0.7e-3 ph cm-2 s-1, respectively, corresponding to a
bulge-to-disk flux ratio in the range 1-3. Assuming a positronium fraction of
0.93 this translates into annihilation rates of 1.5e43 s-1 and 3e42 s-1,
respectively. The ratio of the bulge luminosity to that of the disk is in the
range 3-9. We find no evidence for a point-like source in addition to the
diffuse emission, down to a typical flux limit of 1e-4 ph cm-2 s-1. We also
find no evidence for the positive latitude enhancement that has been reported
from OSSE measurements; our 3 sigma upper flux limit for this feature is 1.5e-4
ph cm-2 s-1. The disk emission can be attributed to the beta+ decay of the
radioactive species 26Al and 44Ti. The bulge emission arises from a different
source which has only a weak or no disk component. We suggest that Type Ia
supernovae and/or low-mass X-ray binaries are the prime candidates for the
source of the galactic bulge positrons. Light dark matter annihilation could
also explain the observed 511 keV bulge emission characteristics.Comment: accepted for publication in A&
Effect of the use of a video tutorial in addition to simulation in learning the maneuvers for shoulder dystocia
The development of video tutorials is flourishing and may make it possible to maintain knowledge learned during instruction with simulation. The aim of this study was to assess the effect of adding a video tutorial to a lecture and simulation for learning the maneuvers and protocol for the management of shoulder dystocia. Student midwives and medical students attended a lecture class including instruction about maneuvers and a presentation of an algorithm for the management of shoulder dystocia. They were randomized into two groups. The video group was reminded every two weeks to watch a short tutorial. The control group was reminded to consult the slide show. At the end of two months, they were evaluated by graders. The practice, theory, and global scores of the students in the video group were significantly higher than those of the students in the control group (14.8 vs. 10.4; 5.6 vs. 3.4; and 9.3 vs. 7.0, P<0.001). The scores for the video group improved at the second simulation session, compared with the first (14.8 vs. 9.9; 5.6 vs. 2.9; and 9.3 vs. 7, P<0.001). The addition of a video tutorial improved learning compared to a standard lecture and simulation session alone
Unit-cell for dual-circular polarisation reflectarrays
International audience—A new unit-cell composed of two layers for dual-CP reflectarrays is proposed for the first time with the unique capability to reflect independently and simultaneously the two incident circular polarisations at the same frequency. The experimental results demonstrate that this unit-cell exhibits a 3.8% bandwidth around 8.4 GHz for a phase resolution better than 1.92 bits in LHCP and in RHCP. As a first step towards a reflectarray in dual-CP, this innovative unit-cell is studied in an array configuration. To increase the value of the maximum incidence angle up to 30°, a matching dielectric layer is placed over the cell
Dimerization of hub protein DYNLL1 and bZIP transcription factor CREB3L1 enhances transcriptional activation of CREB3L1 target genes like arginine vasopressin
bZIP transcription factors can function as homodimers or heterodimers through interactions with their disordered coiled-coil domain. Such dimer assemblies are known to influence DNA-binding specificity and/or the recruitment of binding partners, which can cause a functional switch of a transcription factor from being an activator to a repressor. We recently identified the genomic targets of a bZIP transcription factor called CREB3L1 in rat hypothalamic supraoptic nucleus by ChIP-seq. The objective of this study was to investigate the CREB3L1 protein-to-protein interactome of which little is known. For this approach, we created and screened a rat supraoptic nucleus yeast two-hybrid prey library with the bZIP region of rat CREB3L1 as the bait. Our yeast two-hybrid approach captured five putative CREB3L1 interacting prey proteins in the supraoptic nucleus. One interactor was selected by bioinformatic analyses for more detailed investigation by co-immunoprecipitation, immunofluorescent cellular localisation, and reporter assays in vitro. Here we identify dimerisation hub protein Dynein Light Chain LC8-Type 1 as a CREB3L1 interacting protein that in vitro enhances CREB3L1 activation of target genes
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