4,093 research outputs found
Computation of Integral Bases
Let be a Dedekind domain, the fraction field of , and
a monic irreducible separable polynomial. For a given non-zero prime ideal
of we present in this paper a new method to compute a
-integral basis of the extension of determined by . Our
method is based on the use of simple multipliers that can be constructed with
the data that occurs along the flow of the Montes Algorithm. Our construction
of a -integral basis is significantly faster than the similar
approach from and provides in many cases a priori a triangular basis.Comment: 22 pages, 4 figure
The impact of climatic and atmospheric teleconnections on the brine inventory over the Laptev Sea shelf between 2007 and 2011
Export of brine-enriched water from Siberian shelves is thought to be a key parameter in
maintaining the Arctic Halocline, which isolates the fresh and cold surface water from the warm Atlantic water and thus prevent dramatic change in the Arctic sea-ice
thermodynamic. In this study, we used five years of oxygen isotope and hydrological
summer surveys to better understand the factors controlling the brine inventory and
distribution over the Laptev Sea shelf. The inventory was maximal in 2011 and 2007 and
minimal in 2010. The brine inventory interannual variations are coherent with the winter Arctic Oscillation index that was maximal in 2011 and 2007 and minimal in 2010, which is known to modulate Arctic winds and sea-ice export pattern. While we should remain
cautious since our record is limited to 5-years, our results suggest that the combined
effect of the Arctic Oscillation and of the Arctic Dipole is the main factor controlling the
annual variations in the inventory of brine-enriched waters from the Laptev Sea shelf
between 2007 and 2011, especially during extreme negative Arctic Oscillation and Arctic
Dipole conditions as in 2010
Electronic correlations in double ionization of atoms in pump-probe experiments
The ionization dynamics of a two-electron atom in an attosecond XUV-infrared
pump-probe experiment is simulated by solving the time-dependent two-electron
Schr\"odinger equation. A dramatic change of the double ionization (DI) yield
with variation of the pump-probe delay is reported and the governing role of
electron-electron correlations is shown. The results allow for a direct control
of the DI yield and of the relative strength of double and single ionization
Noise properties of nanoscale YBCO Josephson junctions
We present electric noise measurements of nanoscale biepitaxial YBa2Cu3O(7-x)
(YBCO) Josephson junctions fabricated by two different lithographic methods.
The first (conventional) technique defines the junctions directly by ion
milling etching through an amorphous carbon mask. The second (soft patterning)
method makes use of the phase competition between the superconducting YBCO
(Y123) and the insulating Y2BaCuO5 (Y211) phase at the grain boundary interface
on MgO (110) substrates. The voltage noise properties of the two methods are
compared in this study. For all junctions (having a thickness of 100 nm and
widths of 250-500 nm) we see a significant amount of individual charge traps.
We have extracted an approximate value for the effective area of the charge
traps from the noise data. From the noise measurements we infer that the soft
patterned junctions with a grain boundary (GB) interface manifesting a large
c-axis tunneling component have a uniform barrier and a SIS like behavior. The
noise properties of soft patterned junctions having a GB interface dominated by
transport parallel to the ab-planes are in accordance with a resonant tunneling
barrier model. The conventionally patterned junctions, instead, have suppressed
superconducting transport channels with an area much less than the nominal
junction area. These findings are important for the implementation of nanosized
Josephson junctions in quantum circuits.Comment: 11 Pages, 10 figure
Role of word-of-mouth for programs of voluntary vaccination: A game-theoretic approach
We propose a model describing the synergetic feedback between word-of-mouth
(WoM) and epidemic dynamics controlled by voluntary vaccination. We combine a
game-theoretic model for the spread of WoM and a compartmental model describing
disease dynamics in the presence of a program of voluntary vaccination.
We evaluate and compare two scenarios, depending on what WoM disseminates: (1)
vaccine advertising, which may occur whether or not an epidemic is ongoing and
(2) epidemic status, notably disease prevalence. Understanding the synergy
between the two strategies could be particularly important for organizing
voluntary vaccination campaigns. We find that, in the initial phase of an
epidemic, vaccination uptake is determined more by vaccine advertising than the
epidemic status. As the epidemic progresses, epidemic status become
increasingly important for vaccination uptake, considerably accelerating
vaccination uptake toward a stable vaccination coverage.Comment: 10 pages, 2 figure
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