65,468 research outputs found
New Cosmological Structures on Medium Angular Scales Detected with the Tenerife Experiments
We present observations at 10 and 15 GHz taken with the Tenerife experiments
in a band of the sky at Dec.=+35 degrees. These experiments are sensitive to
multipoles in the range l=10-30. The sensitivity per beam is 56 and 20 microK
for the 10 and the 15 GHz data, respectively. After subtraction of the
prediction of known radio-sources, the analysis of the data at 15 GHz at high
Galactic latitude shows the presence of a signal with amplitude Delta Trms ~ 32
microK. In the case of a Harrison-Zeldovich spectrum for the primordial
fluctuations, a likelihood analysis shows that this signal corresponds to a
quadrupole amplitude Q_rms-ps=20.1+7.1-5.4 microK, in agreement with our
previous results at Dec.+=40 degrees and with the results of the COBE DMR.
There is clear evidence for the presence of individual features in the RA range
190 degrees to 250 degrees with a peak to peak amplitude of ~110 microK. A
preliminary comparison between our results and COBE DMR predictions for the
Tenerife experiments clearly indicates the presence of individual features
common to both. The constancy in amplitude over such a large range in frequency
(10-90 GHz) is strongly indicative of an intrinsic cosmological origin for
these structures.Comment: ApJ Letters accepted, 13 pages Latex (uses AASTEX) and 4 encapsulated
postscript figures
Tadpole renormalization and relativistic corrections in lattice NRQCD
We make a comparison of two tadpole renormalization schemes in the context of
the quarkonium hyperfine splittings in lattice NRQCD. Improved gauge-field and
NRQCD actions are analyzed using the mean-link in Landau gauge, and
using the fourth root of the average plaquette . Simulations are done
for , , and systems. The hyperfine splittings are
computed both at leading and at next-to-leading order in the relativistic
expansion. Results are obtained at lattice spacings in the range of about
0.14~fm to 0.38~fm. A number of features emerge, all of which favor tadpole
renormalization using . This includes much better scaling behavior of
the hyperfine splittings in the three quarkonium systems when is
used. We also find that relativistic corrections to the spin splittings are
smaller when is used, particularly for the and
systems. We also see signs of a breakdown in the NRQCD expansion when the bare
quark mass falls below about one in lattice units. Simulations with
also appear to be better behaved in this context: the bare quark masses turn
out to be larger when is used, compared to when is used on
lattices with comparable spacings. These results also demonstrate the need to
go beyond tree-level tadpole improvement for precision simulations.Comment: 14 pages, 7 figures (minor changes to some phraseology and
references
Raised cortisol excretion rate in urine and contamination by topical steroids
No abstract available
Precise determination of the lattice spacing in full lattice QCD
We compare three different methods to determine the lattice spacing in
lattice QCD and give results from calculations on the MILC ensembles of
configurations that include the effect of , and sea quarks. It is
useful, for ensemble to ensemble comparison, to express the results as giving a
physical value for , a parameter from the heavy quark potential. Combining
the three methods gives a value for in the continuum limit of
0.3133(23)(3) fm. Using the MILC values for , this corresponds to a
value for the parameter of 0.4661(38) fm. We also discuss how to use the
for determining the lattice spacing and tuning the -quark mass
accurately, by giving values for (0.6858(40) GeV) and
(0.1815(10) GeV).Comment: 15 page
Improved impact performance of marine sandwich panels using through-thickness reinforcement: Experimental results
This paper presents results from a test developed to simulate the water impact
(slamming) loading of sandwich boat structures. A weighted elastomer ball is
dropped from increasing heights onto rigidly supported panels until damage is
detected. Results from this test indicate that honeycomb core sandwich panels,
the most widely used material for racing yacht hulls, start to damage due to
core crushing at impact energies around 550 J. Sandwich panels of the same areal
weight and with the same carbon/epoxy facings but using a novel foam core
reinforced in the thickness direction with pultruded carbon fibre pins, do not
show signs of damage until above 1200 J impact energy. This suggests that these
will offer significantly improved resistance to wave impact. Quasi-static test
results cannot be used to predict impact resistance here as the crush strength
of the pinned foam is more sensitive to loading rate than that of the honeycomb
core
So what do we do with the rest of the day? Going beyond the pre-shot routine in professional golf
Optimally focused attention has been shown to be a key psychological characteristic for peak performance in golf; a feature commonly achieved with a pre-shot routine. However, research to date has yet to address how a golfer’s attention should best shift across the broader period of a whole game, or even including pre-event preparations, to support the pre-shot process and, ultimately, performance. Reflecting this knowledge gap, the present review aims to clarify current conceptual understanding and best practice against this wider perspective on attentional control, as well as highlight areas which must be considered for advances to be made. Specifically, research is required on the cognitive, behavioral, and temporal elements of routines used between shots and holes. Furthermore, to manage the attentional demands of the entire golf performance experience, such investigation also needs to explore the critical role of the support team and pre-tournament planning
Magnetoconductance switching in an array of oval quantum dots
Employing oval shaped quantum billiards connected by quantum wires as the
building blocks of a linear quantum dot array, we calculate the ballistic
magnetoconductance in the linear response regime. Optimizing the geometry of
the billiards, we aim at a maximal finite- over zero-field ratio of the
magnetoconductance. This switching effect arises from a relative phase change
of scattering states in the oval quantum dot through the applied magnetic
field, which lifts a suppression of the transmission characteristic for a
certain range of geometry parameters. It is shown that a sustainable switching
ratio is reached for a very low field strength, which is multiplied by
connecting only a second dot to the single one. The impact of disorder is
addressed in the form of remote impurity scattering, which poses a temperature
dependent lower bound for the switching ratio, showing that this effect should
be readily observable in experiments.Comment: 11 pages, 8 figure
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