10,715 research outputs found
Dose Administration Aid system in the elderly: testing student active participation in the implementation of a new service for community pharmacy
Poster presented at the 9th PCNE (Pharmaceutical Care Network Europe) Working Conference
Rotating Hele-Shaw cells with ferrofluids
We investigate the flow of two immiscible, viscous fluids in a rotating
Hele-Shaw cell, when one of the fluids is a ferrofluid and an external magnetic
field is applied. The interplay between centrifugal and magnetic forces in
determining the instability of the fluid-fluid interface is analyzed. The
linear stability analysis of the problem shows that a non-uniform, azimuthal
magnetic field, applied tangential to the cell, tends to stabilize the
interface. We verify that maximum growth rate selection of initial patterns is
influenced by the applied field, which tends to decrease the number of
interface ripples. We contrast these results with the situation in which a
uniform magnetic field is applied normally to the plane defined by the rotating
Hele-Shaw cell.Comment: 12 pages, 3 ps figures, RevTe
Enhanced solar anti-neutrino flux in random magnetic fields
We discuss the impact of the recent KamLAND constraint on the solar
anti-neutrino flux on the analysis of solar neutrino data in the presence of
Majorana neutrino transition magnetic moments and solar magnetic fields. We
consider different stationary solar magnetic field models, both regular and
random, highlighting the strong enhancement in the anti-neutrino production
rates that characterize turbulent solar magnetic field models. Moreover, we
show that for such magnetic fields inside the Sun, one can constrain the
intrinsic neutrino magnetic moment down to the level of mu_nu lessthan few
times 10^-12 x mu_B irrespective of details of the underlying turbulence model.
This limit is more stringent than all current experimental sensitivities, and
similar to the most stringent bounds obtained from stellar cooling. We also
comment on the robustness of this limit and show that at most it might be
weakened by one order of magnitude, under very unlikely circumstances.Comment: 25 pages, 5 figures; final version to appear in Phys. Rev.
Unparticle physics and neutrino phenomenology
We have constrained unparticle interactions with neutrinos and electrons
using available data on neutrino-electron elastic scattering and the four CERN
LEP experiments data on mono photon production. We have found that, for
neutrino-electron elastic scattering, the MUNU experiment gives better
constraints than previous reported limits in the region d>1.5. The results are
compared with the current astrophysical limits, pointing out the cases where
these limits may or may not apply. We also discuss the sensitivity of future
experiments to unparticle physics. In particular, we show that the measurement
of coherent reactor neutrino scattering off nuclei could provide a good
sensitivity to the couplings of unparticle interaction with neutrinos and
quarks. We also discuss the case of future neutrino-electron experiments as
well as the International Linear Collider.Comment: 20 pages, 5 figures. Minor changes, final versio
Observation of slow light in the noise spectrum of a vertical external cavity surface emitting laser
The role of coherent population oscillations is evidenced in the noise
spectrum of an ultra-low noise lasers. This effect is isolated in the intensity
noise spectrum of an optimized single-frequency vertical external cavity
surface emitting laser. The coherent population oscillations induced by the
lasing mode manifest themselves through their associated dispersion that leads
to slow light effects probed by the spontaneous emission present in the
non-lasing side modes.Comment: accepted for publication in Phys. Rev. Let
Numerical and analytical modeling of unsteady viscoelastic flows: the start-up and pulsating test case problems
In this paper two test cases adequate for the assessment of viscoelastic flow codes under unsteady flow conditions are investigated. For one of them an analytical solution is also derived.
First, the start-up of planar Poiseuille flow between two parallel plates was tackled. For upper-convected Maxwell and Oldroyd-B models there exist analytical solutions making it possible to evaluate exactly the discretization errors of the transient numerical method. Good agreement was found between the
present numerical results and those analytical solutions, especially for “shock” propagation. For the UCM
fluid, small numerical oscillations were observed at points where the time derivative of velocity was discontinuous, but for the Oldroyd-B fluid a smooth development of the transient evolution was obtained. Results with the PTT model without solvent viscosity and the FENE fluids were also obtained and, as expected, the behaviour was similar to that found for the UCM and Oldroyd-B fluids, respectively.
Then, a pulsating flowproblemwas studied. In this test case the flow is generated by a periodic ressure gradient
superimposed on a constant Poiseuille flow. The analytical solution for pulsatile Oldroyd-B flow in a channel was derived as part of the work and, again, difficulties in obtaining accurate numerical solutions with the UCM model were encountered, being necessary to employ extremely refined meshes. For the Oldroyd-B fluid no difficulties were found and the accuracy tended to improve with larger solvent viscosity parameter
Symmetry breaking effects upon bipartite and multipartite entanglement in the XY model
We analyze the bipartite and multipartite entanglement for the ground state
of the one-dimensional XY model in a transverse magnetic field in the
thermodynamical limit. We explicitly take into account the spontaneous symmetry
breaking in order to explore the relation between entanglement and quantum
phase transitions. As a result we show that while both bipartite and
multipartite entanglement can be enhanced by spontaneous symmetry breaking deep
into the ferromagnetic phase, only the latter is affected by it in the vicinity
of the critical point. This result adds to the evidence that multipartite, and
not bipartite, entanglement is the fundamental indicator of long range
correlations in quantum phase transitions.Comment: 13 pages, 19 figures, comments welcome. V2: small changes, published
versio
Gravity-driven instability in a spherical Hele-Shaw cell
A pair of concentric spheres separated by a small gap form a spherical
Hele-Shaw cell. In this cell an interfacial instability arises when two
immiscible fluids flow. We derive the equation of motion for the interface
perturbation amplitudes, including both pressure and gravity drivings, using a
mode coupling approach. Linear stability analysis shows that mode growth rates
depend upon interface perimeter and gravitational force. Mode coupling analysis
reveals the formation of fingering structures presenting a tendency toward
finger tip-sharpening.Comment: 13 pages, 4 ps figures, RevTex, to appear in Physical Review
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