2,918 research outputs found
Entanglement of a three-level atom interacting with two-modes field in a cavity
The dynamics of the interaction between an atom of three levels interacting
with a quantized field of two modes in a cavity is studied within the rotating
wave approximation, by taking into account experimental values of the
accessible hyperfine levels of alkaline atoms. An equal detuning is considered
to determine the matter-field entanglement, the statistical properties of the
photons, and the occupation probabilities of the atom. For a large detuning or
weak dipolar strength appear the Raman condition, that is, the suppression of
one of his atomic transitions. Analytic expression for the time evolution
operator allows to have also explicit closed expressions for the field and
matter observables.Comment: 37 pages, 9 figure
First insights on Lake General Carrera/Buenos Aires/Chelenko water balance
Lago General Carrera (Chile) also called Lago Buenos Aires (Argentina) or originally Chelenko by the native habitants of the region is located in Patagonia on the Chilean-Argentinean border. It is the largest lake in Chile with a surface area of 1850 km<sup>2</sup>. The lake is of glacial/tectonic origin and surrounded by the Andes mountain range. The lake drains primarily to the Pacific Ocean to the west, through the Baker River (one of Chile's largest rivers), and intermittently eastward to the Atlantic Ocean. We report ongoing results from an investigation of the seasonal hydrological cycle of the lake basin. The contribution by river input through snowmelt from the Andes is of primary importance, though the lack of water input by ungaged rivers is also critical. We present the main variables involved in the water balance of Lake General Carrera/Buenos Aires/Chelenko, such as influent and effluent river flows, precipitation, and evaporation, all this based mostly in in-situ information
Determination in soils of PAH produced by combustion of biomass under different conditions
4 pages, 2 figures, 2 tables, 25 references.-- Instituto de Recursos Naturales y Agrobiologia, C.S.I.C., Apartado 1052, E-41080 Sevilla, SpainThe nature and concentrations in soils of polynuclear aromatic hydrocarbons (PAH) generated by combustion of pine biomass under different conditions was determined by gas chromatography-mass spectrometry after their enrichment by a simple clean-up procedure. The patterns of pyrogenic PAH, presumably generated by thermal aromatization of biogenic precursors, vary for each sample. When burned at moderate temperature for a long period of time the most abundant homologues generated were alkylated derivatives of naphthalene, whereas phenanthrene alkyl derivatives were predominant after a forest wildfire, where higher temperatures are reached in less time. More condensed PAH included in well-known priority pollutant lists were detected only in minor amounts. No long persistence of PAH was observed in some soil samples analysed.Peer reviewe
Exponential dynamical localization for the almost Mathieu operator
We prove that the exponential moments of the position operator stay bounded
for the supercritical almost Mathieu operator with Diophantine frequency
New characterizations of the region of complete localization for random Schr\"odinger operators
We study the region of complete localization in a class of random operators
which includes random Schr\"odinger operators with Anderson-type potentials and
classical wave operators in random media, as well as the Anderson tight-binding
model. We establish new characterizations or criteria for this region of
complete localization, given either by the decay of eigenfunction correlations
or by the decay of Fermi projections. (These are necessary and sufficient
conditions for the random operator to exhibit complete localization in this
energy region.) Using the first type of characterization we prove that in the
region of complete localization the random operator has eigenvalues with finite
multiplicity
Electromiograph Parameters in Thedysfunctional Patient with Open Bite
INTRODUCTION: Open bite is an occlusal problem that appears in 0.5% of the population, and is more frequent in women. There is correlation between open bite and dysfunctional syndrome with TMJ disorders.
AIM OF THE STUDY: We attempted to analyze muscular parameters in patients with open bite treated with an occlusal splint by EMG recordings.
MATERIAL AND METHODS: Myotronics K6 electromiograph can provide information in the following situations: maximum force bite, lateral and protrusion movements, with and without an occlusal splint.
RESULTS: In maximum force bite with the occlusal splint more activity was found in the elevator muscles with a lack of dygastric activity. There was less EMG activity in protrusive and lateral
movements with occlusal splint.
CONCLUSION: With better support between the dental arches (occlusal splint) more activity was obtained in the elevators when biting, and when interferences were eliminated activity in the contralateral muscles was reduced
Spectral and Localization Properties for the One-Dimensional Bernoulli Discrete Dirac Operator
A 1D Dirac tight-binding model is considered and it is shown that its
nonrelativistic limit is the 1D discrete Schr?odinger model. For random
Bernoulli potentials taking two values (without correlations), for typical
realizations and for all values of the mass, it is shown that its spectrum is
pure point, whereas the zero mass case presents dynamical delocalization for
specific values of the energy. The massive case presents dynamical localization
(excluding some particular values of the energy). Finally, for general
potentials the dynamical moments for distinct masses are compared, especially
the massless and massive Bernoulli cases.Comment: no figure; 24 pages; to appear in Journal of Mathematical Physic
- …