1,700 research outputs found
Psychotropic drug prescriptions in hospitalized ederly psychiatric patients: comparison with adult psychiatric patients
RÉSUMÉ
Comparaison dés habitudes de prescription de médicaments psychotropes dans des cliniques de psychiatrie adulte et de psychogériatrie
Afin de pouvoir comparer l'utilisation de médicaments psychotropes et non psychotropes, la proportion des nouveaux et celle des anciens antidépresseurs ou antipsychotiques, ce travail a eu pour but d'étudier les prescriptions médicamenteuses dans deux groupes de patients hospitalisés, l'un en milieu psychiatrique adulte (de 18 à 64 ans), l'autre en milieu psychogériatrique (plus de 64 ans).
Lors d'un jour de référence en Mai 2000, toutes les prescriptions médicamenteuses dans deux hôpitaux psychiatriques universitaires abritant l'un une population adulte, l'autre gériatrique, ont été relevées chez tous les patients. Le coût financier total par patient a été comparé en tenant compte de la proportion des médicaments non psychotropes.
La médication de 61 patients adultes et de 82 patients gériatriques a ainsi été analysée. Le nombre moyen de médicaments non psychotropes par patient était plus élevé dans la population âgée (p< 0.001), ce qui se reflète également par une prescription totale de médicaments par patient en moyenne plus élevée dans cette population (p<0.001). L'utilisation de benzodiazépines était inférieure dans là population psychogériatrique (p<0.001), même si l'on y additionne celle en association avec les antidépresseurs (p<0.001). Le coût financier du traitement pharmacologique quotidien d'un patient adulte était significativement inférieur à celui d'un patient gériatrique dont la comédication somatique est nécessairement plus importante (9.3 ± 7.2 CHF/patient contre 14.1 ± 9.5 CHF/patient) (p<0.009).
En conclusion, cette étude confirme l'importance des habitudes locales dans la prescription médicamenteuse par les médecins, à l'exception de l'utilisation des benzodiazépines pour lesquelles les psychogériâtres semblent moins favorables
Quantum ballistic experiment on antihydrogen fall
We study an interferometric approach to measure gravitational mass of
antihydrogen. The method consists of preparing a coherent superposition of
antihydrogen quantum state localized near a material surface in the
gravitational field of the Earth, and then observing the time distribution of
annihilation events followed after the free fall of an initially prepared
superposition from a given height to the detector plate. We show that a
corresponding time distribution is related to the momentum distribution in the
initial state that allows its precise measurement. This approach is combined
with a method of production of a coherent superposition of gravitational states
by inducing a resonant transition using oscillating gradient magnetic field. We
estimate an accuracy of measuring the gravitational mass of antihydrogen atom
which could be deduced from such a measurement.Comment: arXiv admin note: text overlap with arXiv:1403.478
Casimir-Polder shifts on quantum levitation states
An ultracold atom above a horizontal mirror experiences quantum reflection
from the attractive Casimir-Polder interaction, which holds it against gravity
and leads to quantum levitation states. We analyze this system by using a
Liouville transformation of the Schr\"odinger equation and a Langer coordinate
adapted to problems with a classical turning point. Reflection on the
Casimir-Polder attractive well is replaced by reflection on a repulsive wall
and the problem is then viewed as an ultracold atom trapped inside a cavity
with gravity and Casimir-Polder potentials acting respectively as top and
bottom mirrors. We calculate numerically Casimir-Polder shifts of the energies
of the cavity resonances and propose a new approximate treatment which is
precise enough to discuss spectroscopy experiments aiming at tests of the weak
equivalence principle on antihydrogen. We also discuss the lifetimes by
calculating complex energies associated with cavity resonances.Comment: Accepted in PR
Gravity tests in the solar system and the Pioneer anomaly
We build up a new phenomenological framework associated with a minimal
generalization of Einsteinian gravitation theory. When linearity, stationarity
and isotropy are assumed, tests in the solar system are characterized by two
potentials which generalize respectively the Newton potential and the parameter
of parametrized post-Newtonian formalism. The new framework seems to
have the capability to account for the Pioneer anomaly besides other gravity
tests.Comment: 5 pages. Accepted version, to appear in Modern Physics Letters
Quantum reflection of antihydrogen from nanoporous media
We study quantum reflection of antihydrogen atoms from nanoporous media due
to the Casimir-Polder (CP) potential. Using a simple effective medium model, we
show a dramatic increase of the probability of quantum reflection of
antihydrogen atoms if the porosity of the medium increases. We discuss the
limiting case of reflections at small energies, which have interesting
applications for trapping and guiding antihydrogen using material walls
A practical mode system for recursive definitions
In call-by-value languages, some mutually-recursive value definitions can be
safely evaluated to build recursive functions or cyclic data structures, but
some definitions (let rec x = x + 1) contain vicious circles and their
evaluation fails at runtime. We propose a new static analysis to check the
absence of such runtime failures.
We present a set of declarative inference rules, prove its soundness with
respect to the reference source-level semantics of Nordlander, Carlsson, and
Gill (2008), and show that it can be (right-to-left) directed into an
algorithmic check in a surprisingly simple way.
Our implementation of this new check replaced the existing check used by the
OCaml programming language, a fragile syntactic/grammatical criterion which let
several subtle bugs slip through as the language kept evolving. We document
some issues that arise when advanced features of a real-world functional
language (exceptions in first-class modules, GADTs, etc.) interact with safety
checking for recursive definitions
Transitional forms between the three domains of life and evolutionary implications
The question as to the origin and relationship between the three domains of life is lodged in a phylogenetic impasse. The dominant paradigm is to see the three domains as separated. However, the recently characterized bacterial species have suggested continuity between the three domains. Here, we review the evidence in support of this hypothesis and evaluate the implications for and against the models of the origin of the three domains of life. The existence of intermediate steps between the three domains discards the need for fusion to explain eukaryogenesis and suggests that the last universal common ancestor was complex. We propose a scenario in which the ancestor of the current bacterial Planctomycetes, Verrucomicrobiae and Chlamydiae superphylum was related to the last archaeal and eukaryotic common ancestor, thus providing a way out of the phylogenetic impasse
Quantum reflection of antihydrogen from Casimir potential above matter slabs
We study quantum reflection of antihydrogen atoms from matter slabs due to
the van der Waals/Casimir-Polder (vdW/CP) potential. By taking into account the
specificities of antihydrogen and the optical properties and width of the slabs
we calculate realistic estimates for the potential and quantum reflection
amplitudes. Next we discuss the paradoxical result of larger reflection
coefficients estimated for weaker potentials in terms of the Schwarzian
derivative. We analyze the limiting case of reflections at small energies,
which are characterized by a scattering length and have interesting
applications for trapping and guiding antihydrogen using material walls
Whispering Gallery States of Antihydrogen
We study theoretically interference of the long-living quasistationary
quantum states of antihydrogen atoms, localized near a concave material
surface. Such states are an antimatter analog of the whispering gallery states
of neutrons and matter atoms, and similar to the whispering gallery modes of
sound and electro-magnetic waves. Quantum states of antihydrogen are formed by
the combined effect of quantum reflection from van der Waals/Casimir-Polder
(vdW/CP) potential of the surface and the centrifugal potential. We point out a
method for precision studies of quantum reflection of antiatoms from vdW/CP
potential; this method uses interference of the whispering gallery states of
antihydrogen.Comment: 13 pages 7 figure
Casimir effect with rough metallic mirrors
We calculate the second order roughness correction to the Casimir energy for
two parallel metallic mirrors. Our results may also be applied to the
plane-sphere geometry used in most experiments. The metallic mirrors are
described by the plasma model, with arbitrary values for the plasma wavelength,
the mirror separation and the roughness correlation length, with the roughness
amplitude remaining the smallest length scale for perturbation theory to hold.
From the analysis of the intracavity field fluctuations, we obtain the
Casimir energy correction in terms of generalized reflection operators, which
account for diffraction and polarization coupling in the scattering by the
rough surfaces. We present simple analytical expressions for several limiting
cases, as well as numerical results that allow for a reliable calculation of
the roughness correction in real experiments. The correction is larger than the
result of the Proximity Force Approximation, which is obtained from our theory
as a limiting case (very smooth surfaces).Comment: 16 page
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