10,352 research outputs found
A VLBI polarization study of SiO masers towards VY CMa
Maser emission from the SiO molecule has been widely observed in the
near-circumstellar envelopes of late-type, evolved stars. VLBI images can
resolve individual SiO maser spots, providing information about the kinematics
and magnetic field in the extended atmospheres of these stars. This poster
presents full polarization images of several SiO maser lines towards the
supergiant star VY CMa. VY CMa is a particularly strong SiO maser source and
allows observations of a wide range of maser transitions. We discuss
implications of these observations for VY CMa morphology, polarization, and
pumping models.Comment: 3 pages, 1 figure: based on a poster paper at IAU Symposium 242:
Astrophysical masers and their environments, held at Alice Springs
(Australia), from March 12-16, 200
Detection of spin reversal and nutations through current measurements
The dynamics of a single spin embedded in a the tunnel junction between
ferromagnetic contacts is strongly affected by the exchange coupling to the
tunneling electrons. Moment reversal of the local spin induced by the bias
voltage across the junction is shown to have a measurable effect on the
tunneling current. Furthermore, the frequency of a harmonic bias voltage is
picked up by the local spin dynamics and transferred back to the current
generating a double frequency component.Comment: 5 pages, 5 figures; published version (with minor corrections
The angular power spectrum of radio emission at 2.3 GHz
We have analysed the Rhodes/HartRAO survey at 2326 MHz and derived the global
angular power spectrum of Galactic continuum emission. In order to measure the
angular power spectrum of the diffuse component, point sources were removed
from the map by median filtering. A least-square fit to the angular power
spectrum of the entire survey with a power law spectrum C_l proportional to
l^{-alpha}, gives alpha = 2.43 +/- 0.01 for l = 2-100. The angular power
spectrum of radio emission appears to steepen at high Galactic latitudes and
for observed regions with |b| > 20 deg, the fitted spectral index is alpha =
2.92 +/- 0.07. We have extrapolated this result to 30 GHz (the lowest frequency
channel of Planck) and estimate that no significant contribution to the sky
temperature fluctuation is likely to come from synchrotron at degree-angular
scalesComment: 10 pages, 10 figures, accepted for publication by Astronomy &
Astrophysic
Network Structure Explains the Impact of Attitudes on Voting Decisions
Attitudes can have a profound impact on socially relevant behaviours, such as
voting. However, this effect is not uniform across situations or individuals,
and it is at present difficult to predict whether attitudes will predict
behaviour in any given circumstance. Using a network model, we demonstrate that
(a) more strongly connected attitude networks have a stronger impact on
behaviour, and (b) within any given attitude network, the most central attitude
elements have the strongest impact. We test these hypotheses using data on
voting and attitudes toward presidential candidates in the US presidential
elections from 1980 to 2012. These analyses confirm that the predictive value
of attitude networks depends almost entirely on their level of connectivity,
with more central attitude elements having stronger impact. The impact of
attitudes on voting behaviour can thus be reliably determined before elections
take place by using network analyses.Comment: Final version published in Scientific Report
Detecting Vanishing Dimensions Via Primordial Gravitational Wave Astronomy
Lower-dimensionality at higher energies has manifold theoretical advantages
as recently pointed out. Moreover, it appears that experimental evidence may
already exists for it - a statistically significant planar alignment of events
with energies higher than TeV has been observed in some earlier cosmic ray
experiments. We propose a robust and independent test for this new paradigm.
Since (2+1)-dimensional spacetimes have no gravitational degrees of freedom,
gravity waves cannot be produced in that epoch. This places a universal maximum
frequency at which primordial waves can propagate, marked by the transition
between dimensions. We show that this cut-off frequency may be accessible to
future gravitational wave detectors such as LISA.Comment: Somewhat expanded version with discussions that could not fit into
the PRL version; references adde
Magnetic Switching of Phase-Slip Dissipation in NbSe2 Nanobelts
The stability of the superconducting dissipationless and resistive states in
single-crystalline NbSe2 nanobelts is characterized by transport measurements
in an external magnetic field (H). Current-driven electrical measurements show
voltage steps, indicating the nucleation of phase-slip structures. Well below
the critical temperature, the position of the voltage steps exhibits a sharp,
periodic dependence as a function of H. This phenomenon is discussed in the
context of two possible mechanisms: the interference of the order parameter and
the periodic rearrangement of the vortex lattice within the nanobelt.Comment: 4 figure
Phase 1 Safety and Tolerability Study of BMP-7 in Symptomatic Knee Osteoarthritis
BACKGROUND: There are no proven therapies that modify the structural changes associated with osteoarthritis (OA). Preclinical data suggests that intra-articular recombinant human BMP-7 (bone morphogenetic protein-7) has reparative effects on cartilage, as well as on symptoms of joint pain. The objective of this study was to determine the safety and tolerability as well as dose-limiting toxicity and maximal tolerated dose of intra-articular BMP-7. The secondary objectives were to determine the effect on symptomatic responses through 24 weeks. METHODS: This was a Phase 1, double-blind, randomized, multi-center, placebo-controlled, single-dose escalation safety study consisting of 4 dosing cohorts in participants with knee OA. Each cohort was to consist of 8 treated participants, with treatment allocation in a 3:1 active (intra-articular BMP-7) to placebo ratio. Eligible participants were persons with symptomatic radiographic knee OA over the age of 40. The primary objective of this study was to determine the safety and tolerability of BMP-7 including laboratory assessments, immunogenicity data and radiographic assessments. Secondary objectives were to determine the proportion of participants with a 20%, 50%, and 70% improvement in the WOMAC pain and function subscales at 4, 8, 12, and 24 weeks. Other secondary outcomes included the change from baseline to 4, 8, 12, and 24 weeks for the OARSI responder criteria. RESULTS: The mean age of participants was 60 years and 73% were female. All 33 participants who were enrolled completed the study and most adverse events were mild or moderate and were similar in placebo and BMP-7 groups. The 1 mg BMP-7 group showed a higher frequency of injection site pain and there was no ectopic bone formation seen on plain x-rays. By week 12, most participants in both the BMP-7 and placebo groups experienced a 20% improvement in pain and overall the BMP-7 group was similar to placebo with regard to this measurement. In the participants who received 0.1 mg and 0.3 mg BMP-7, there was a trend toward greater symptomatic improvement than placebo. The other secondary endpoints showed similar trends including the OARSI responder criteria for which the BMP-7 groups had more responders than placebo. CONCLUSIONS: There was no dose limiting toxicity identified in this study. The suggestion of a symptom response, together with the lack of dose limiting toxicity provide further support for the continued development of this product for the treatment of osteoarthritis.ARC Future Fellowship; Stryker Biotec
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