3,877 research outputs found
Enhanced quantized current driven by surface acoustic waves
We present the experimental realization of different approaches to increase
the amount of quantized current which is driven by surface acoustic waves
through split gate structures in a two dimensional electron gas. Samples with
driving frequencies of up to 4.7 GHz have been fabricated without a
deterioration of the precision of the current steps, and a parallelization of
two channels with correspondingly doubled current values have been achieved. We
discuss theoretical and technological limitations of these approaches for
metrological applications as well as for quantum logics.Comment: 3pages, 4eps-figure
First ALMA Observation of a Solar Plasmoid Ejection from an X-ray Bright Point
Eruptive phenomena such as plasmoid ejections or jets are an important
feature of solar activity with the potential for improving our understanding of
the dynamics of the solar atmosphere. Such ejections are often thought to be
signatures of the outflows expected in regions of fast magnetic reconnection.
The 304 A EUV line of Helium, formed at around 10^5 K, is found to be a
reliable tracer of such phenomena, but the determination of physical parameters
from such observations is not straightforward. We have observed a plasmoid
ejection from an X-ray bright point simultaneously at millimeter wavelengths
with ALMA, at EUV wavelengths with AIA, in soft X-rays with Hinode/XRT. This
paper reports the physical parameters of the plasmoid obtained by combining the
radio, EUV and X-ray data. As a result, we conclude that the plasmoid can
consist either of (approximately) isothermal 10^5 K plasma that is optically
thin at 100 GHz, or else a 10^4 K core with a hot envelope. The analysis
demonstrates the value of the additional temperature and density constraints
that ALMA provides, and future science observations with ALMA will be able to
match the spatial resolution of space-borne and other high-resolution
telescopes.Comment: 10 page, 5 figures, accepted for publication in Astrophysical Journal
Letter. The movie can be seen at the following link:
http://hinode.nao.ac.jp/user/shimojo/data_area/plasmoid/movie5.mp
Entanglement Witnesses for Graph States: General Theory and Examples
We present a general theory for the construction of witnesses that detect
genuine multipartite entanglement in graph states. First, we present explicit
witnesses for all graph states of up to six qubits which are better than all
criteria so far. Therefore, lower fidelities are required in experiments that
aim at the preparation of graph states. Building on these results, we develop
analytical methods to construct two different types of entanglement witnesses
for general graph states. For many classes of states, these operators exhibit
white noise tolerances that converge to one when increasing the number of
particles. We illustrate our approach for states such as the linear and the 2D
cluster state. Finally, we study an entanglement monotone motivated by our
approach for graph states.Comment: 12 pages + appendix, 7 figure
The effect of spatial resolution on optical and near-IR studies of stellar clusters: Implications for the origin of the red excess
Recent ground based near-IR studies of stellar clusters in nearby galaxies
have suggested that young clusters remain embedded for 7-10Myr in their
progenitor molecular cloud, in conflict with optical based studies which find
that clusters are exposed after 1-3Myr. Here, we investigate the role that
spatial resolution plays in this apparent conflict. We use a recent catalogue
of young (~\msun) clusters in the nearby spiral
galaxy, M83, along with Hubble Space Telescope (HST) imaging in the optical and
near-IR, and ground based near-IR imaging, to see how the colours (and hence
estimated properties such as age and extinction) are affected by the aperture
size employed, in order to simulate studies of differing resolution. We find
that the near-IR is heavily affected by the resolution, and when aperture sizes
~pc are used, all young/blue clusters move red-ward in colour space, which
results in their appearance as heavily extincted clusters. However, this is due
to contamination from nearby sources and nebular emission, and is not an
extinction effect. Optical colours are much less affected by resolution. Due to
the larger affect of contamination in the near-IR, we find that, in some cases,
clusters will appear to show near-IR excess when large (~pc) apertures are
used. Our results explain why few young (~Myr), low extinction (\av <
1~mag) clusters have been found in recent ground based near-IR studies of
cluster populations, while many such clusters have been found in higher
resolution HST based studies. Additionally, resolution effects appear to (at
least partially) explain the origin of the near-IR excess that has been found
in a number of extragalactic YMCs.Comment: 8 pages, 5 figures, accepted for publication in MNRA
Long-term outcome after traumatic anterior dislocation of the hip
Introduction: Traumatic anterior dislocation of the hip joint is rare. Additional injuries to the hip due to dislocation are even more infrequent. Outcome is limited by osteoarthritic joint degeneration or the occurrence of avascular necrosis of the femoral head. Method: Anterior hip dislocation occurred in ten of 100 patients with traumatic hip dislocations (8 men, mean age: 43, 22-62years) at two major trauma centres, between January 2001 and December 2008. Four patients had impaction fractures of the femoral head and three patients had fractures of the anterior acetabular wall. One patient presented with an open dislocation. In three of the ten patients surgical treatment was necessary. Results: Nine patients were evaluated retrospectively at a follow-up of 4.8±2.3years (mean±SD). The mean scores were 88±19 (Harris Hip-Score), 15±23 (WOMAC-Score), level 6 (UCLA-Score). Four cases presented with only fair clinical or radiological results according to Epstein. AVN with collapse of the femoral head was observed in one. Conclusion: Traumatic anterior hip dislocations presented in six of the ten cases with additional injuries to the hip. Surgical treatment in cases with deep impaction fractures of the femoral head or with large fragments of the acetabulum may improve the outcom
Zakat Program Application For Calculation Using Visual Basic Programming Languages
Computerization on the calculation of Zakat is one of the new breakthrough in theapplication of Islamic teachings and obligations is expected to tithe is not a burden tosociety is but become a habit that can ditumbuh developed so as to create a society ofmutual help and decreases the existing social inequalities
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