641 research outputs found
Techniques for flexible radio-over-fibre networks
Radio-over-fibre systems can efficiently deliver broadband wireless services in access and in-building networks. RoF signal transport and routing techniques are presented which are robust against fibre dispersion and provide capacity-on-demand for high-capacity multi-tone radio signals
Non-relativistic limit of Randall-Sundrum model: solutions, applications and constraints
In the Randall-Sundrum model with one brane, we found the approximate and
exact solutions for gravitational potentials and accelerations of test bodies
in these potentials for different geometrical configurations. We applied these
formulas for calculation of the gravitational interaction between two spheres
and found the approximate and exact expressions for the relative force
corrections to the Newton's gravitational force. We demonstrated that the
difference between relative force corrections for the approximate and exact
cases increases with the parameter (for the fixed distance between
centers of the spheres). On the other hand, this difference increases with
decreasing of the distance between the centers of the spheres (for the fixed
curvature scale parameter ). We got the upper limit for the curvature scale
parameter m. For these values of , the difference
between the approximate and exact solutions is negligible.Comment: LaTex 11 pages, 3 figure
Precision measurement of solar neutrino oscillation parameters by a long-baseline reactor neutrino experiment in Europe
We consider the determination of the solar neutrino oscillation parameters
and by studying oscillations of reactor
anti-neutrinos emitted by nuclear power plants (located mainly in France) with
a detector installed in the Frejus underground laboratory. The performances of
a water Cerenkov detector of 147 kt fiducial mass doped with 0.1% of Gadolinium
(MEMPHYS-Gd) and of a 50 kt scale liquid scintillator detector (LENA) are
compared. In both cases 3 uncertainties below 3% on
and of about 20% on can be obtained after one year of data
taking. The Gadolinium doped Super-Kamiokande detector (SK-Gd) in Japan can
reach a similar precision if the SK/MEMPHYS fiducial mass ratio of 1 to 7 is
compensated by a longer SK-Gd data taking time. Several years of reactor
neutrino data collected by MEMPHYS-Gd or LENA would allow a determination of
and with uncertainties of approximately
1% and 10% at 3, respectively. These accuracies are comparable to those
that can be reached in the measurement of the atmospheric neutrino oscillation
parameters and in long-baseline superbeam
experiments.Comment: 16 pages, 6 figure
Correlation structure in nondipole photoionization
The nondipole parameters that characterize the angular disribution of the
photoelectrons from the 3d subshell of Cs are found to be altered qualitatively
by the inclusion of correlation in the form of interchannel coupling between
the and photoionization channels. A prominent
characteristic maximum is predicted only in the parameters for
photoionization, while the effect for is rather weak. The results
are obtained within the framework of the Generalized Random Phase Approximation
with Exchange (GRPAE), which in addition to the RPAE effects takes into account
the rearrangement of all atomic electrons due to the creation of a 3d vacancy
Tropical dry woodland loss occurs disproportionately in areas of highest conservation value
Tropical and subtropical dry woodlands are rich in biodiversity and carbon. Yet, many of these woodlands are under high deforestation pressure and remain weakly protected. Here, we assessed how deforestation dynamics relate to areas of woodland protection and to conservation priorities across the world's tropical dry woodlands. Specifically, we characterized different types of deforestation frontier from 2000 to 2020 and compared them to protected areas (PAs), Indigenous Peoples' lands and conservation areas for biodiversity, carbon and water. We found that global conservation priorities were always overrepresented in tropical dry woodlands compared to the rest of the globe (between 4% and 96% more than expected, depending on the type of conservation priority). Moreover, about 41% of all dry woodlands were characterized as deforestation frontiers, and these frontiers have been falling disproportionately in areas with important regional (i.e. tropical dry woodland) conservation assets. While deforestation frontiers were identified within all tropical dry woodland classes of woodland protection, they were lower than the average within protected areas coinciding with Indigenous Peoples' lands (23%), and within other PAs (28%). However, within PAs, deforestation frontiers have also been disproportionately affecting regional conservation assets. Many emerging deforestation frontiers were identified outside but close to PAs, highlighting a growing threat that the conserved areas of dry woodland will become isolated. Understanding how deforestation frontiers coincide with major types of current woodland protection can help target context-specific conservation policies and interventions to tropical dry woodland conservation assets (e.g. PAs in which deforestation is rampant require stronger enforcement, inactive deforestation frontiers could benefit from restoration). Our analyses also identify recurring patterns that can be used to test the transferability of governance approaches and promote learning across social–ecological contexts
Amplitude measurements of Faraday waves
A light reflection technique is used to measure quantitatively the surface
elevation of Faraday waves. The performed measurements cover a wide parameter
range of driving frequencies and sample viscosities. In the capillary wave
regime the bifurcation diagrams exhibit a frequency independent scaling
proportional to the wavelength. We also provide numerical simulations of the
full Navier-Stokes equations, which are in quantitative agreement up to
supercritical drive amplitudes of 20%. The validity of an existing perturbation
analysis is found to be limited to 2.5% overcriticaly.Comment: 7 figure
Brane world corrections to Newton's law
We discuss possible variations of the effective gravitational constant with
length scale, predicted by most of alternative theories of gravity and unified
models of physical interactions. After a brief general exposition, we review in
more detail the predicted corrections to Newton's law of gravity in diverse
brane world models. We consider various configurations in 5 dimensions (flat,
de Sitter and AdS branes in Einstein and Einstein-Gauss-Bonnet theories, with
and without induced gravity and possible incomplete graviton localization), 5D
multi-brane systems and some models in higher dimensions. A common feature of
all models considered is the existence of corrections to Newton's law at small
radii comparable with the bulk characteristic length: at such radii, gravity on
the brane becomes effectively multidimensional. Many models contain superlight
perturbation modes, which modify gravity at large scale and may be important
for astrophysics and cosmology.Comment: Brief review, 16 pages, 92 references. Some description and
references adde
A New Solution to the Relative Orientation Problem using only 3 Points and the Vertical Direction
This paper presents a new method to recover the relative pose between two
images, using three points and the vertical direction information. The vertical
direction can be determined in two ways: 1- using direct physical measurement
like IMU (inertial measurement unit), 2- using vertical vanishing point. This
knowledge of the vertical direction solves 2 unknowns among the 3 parameters of
the relative rotation, so that only 3 homologous points are requested to
position a couple of images. Rewriting the coplanarity equations leads to a
simpler solution. The remaining unknowns resolution is performed by an
algebraic method using Grobner bases. The elements necessary to build a
specific algebraic solver are given in this paper, allowing for a real-time
implementation. The results on real and synthetic data show the efficiency of
this method
Search for Third Generation Vector Leptoquarks in p anti-p Collisions at sqrt(s) = 1.96 TeV
We describe a search for a third generation vector leptoquark (VLQ3) that
decays to a b quark and tau lepton using the CDF II detector and 322 pb^(-1) of
integrated luminosity from the Fermilab Tevatron. Vector leptoquarks have been
proposed in many extensions of the standard model (SM). Observing a number of
events in agreement with SM expectations, assuming Yang-Mills (minimal)
couplings, we obtain the most stringent upper limit on the VLQ3 pair production
cross section of 344 fb (493 fb) and lower limit on the VLQ3 mass of 317
GeV/c^2 (251 GeV/c^2) at 95% C.L.Comment: 7 pages, 2 figures, submitted to PR
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