Collision-Dependent Atom Tunnelling Rate in Bose-Einstein Condensates

We show that the interaction (cross-collision) between atoms trapped in distinct sites of a double-well potential can significantly increase the atom tunneling rate for special trap configurations leading to an effective linear Rabi regime of population oscillation between the trap wells. The inclusion of cross-collisional effects significantly extends the validity of the two-mode model approach allowing it to be alternatively employed to explain the recently observed increase of tunneling rates due to nonlinear interactions.Comment: 4 pages, 2 figures. Replaced with improved versio

On the nature of the spin-polarized hole states in a quasi-two-dimensional GaMnAs ferromagnetic layer

A self-consistent calculation of the density of states and the spectral density function is performed in a two-dimensional spin-polarized hole system based on a multiple-scattering approximation. Using parameters corresponding to GaMnAs thin layers, a wide range of Mn concentrations and hole densities have been explored to understand the nature, localized or extended, of the spin-polarized holes at the Fermi level for several values of the average magnetization of the Mn ystem. We show that, for a certain interval of Mn and hole densities, an increase on the magnetic order of the Mn ions come together with a change of the nature of the states at the Fermi level. This fact provides a delocalization of spin-polarized extended states anti-aligned to the average Mn magnetization, and a higher spin-polarization of the hole gas. These results are consistent with the occurrence of ferromagnetism with relatively high transition temperatures observed in some thin film samples and multilayered structures of this material.Comment: 3 page

Optimal Conditions for Atomic Homodyne Detection on Bose-Einstein Condensates

The dynamics of a two-mode Bose-Einstein condensate trapped in a double-well potential results approximately in an effective Rabi oscillation regime of exchange of population between both wells for sufficiently strong overlap between the modes functions. Facing this system as a temporal atomic beam splitter we show that this regime is optimal for a nondestructive atom-number measurement allowing an atomic homodyne detection, thus yielding indirect relative phase information about one of the two-mode condensates.Comment: 9 pages, 5 figure

Magnetic ordering in GaAlAs:Mn double well structure

The magnetic order in the diluted magnetic semiconductor barrier of double AlAs/GaAs: Mn quantum well structures is investigated by Monte Carlo simulations. A confinement adapted RKKY mechanism is implemented for indirect exchange between Mn ions mediated by holes. It is shown that, depending on the barrier width and the hole concentration a ferromagnetic or a spin-glass order can be established.Comment: 3 figure

Spin-polarized transport in ferromagnetic multilayered semiconductor nanostructures

The occurrence of inhomogeneous spin-density distribution in multilayered ferromagnetic diluted magnetic semiconductor nanostructures leads to strong dependence of the spin-polarized transport properties on these systems. The spin-dependent mobility, conductivity and resistivity in (Ga,Mn)As/GaAs,(Ga,Mn)N/GaN, and (Si,Mn)/Si multilayers are calculated as a function of temperature, scaled by the average magnetization of the diluted magnetic semiconductor layers. An increase of the resistivity near the transition temperature is obtained. We observed that the spin-polarized transport properties changes strongly among the three materials.Comment: 3 pages, 4 figure

Neonatal Infant Pain Scale: Cross-Cultural Adaptation and Validation in Brazil

Context: The Neonatal Infant Pain Scale (NIPS), initially developed in Canada, has been previously used but not adequately adapted and validated for use in Brazil. Objectives: The goal of the present study was to perform a cross-cultural adaptation and clinical validation of the NIPS for use in the Brazilian population. Methods: The instrument was adapted based on the method outlined by Beaton et al., including the production and combination of translated versions, back-translation, committee review, and pilot testing. The psychometric properties of the adapted instrument, including its validity, reliability, and internal consistency, were tested in a clinical validation study. The sample comprised 60 at-term newborns who were evaluated by six nurses as they experienced vaccination. Psychometric properties were evaluated using Student's t-tests, prevalence-adjusted and bias-adjusted kappa scores, the Bland-Altman method, and Cronbach's alpha coefficients. Results: The Brazilian version of the NIPS (Escala de Dor no Recém-Nascido [NIPS-Brazil]) demonstrated excellent interobserver and intraobserver reliability. Total NIPS-Brazil scores yielded prevalence-adjusted and bias-adjusted kappa scores of 0.93, whereas the Bland-Altman method revealed interobserver and intraobserver reliability values of 95% and 90%, respectively. The NIPS-Brazil had adequate internal consistency, as evidenced by a Cronbach's alpha of 0.762. Conclusion: The NIPS was successfully adapted for use in Brazil and is now available for use in the assessment of acute pain in at-term newborns in Brazil

Prevention and non-pharmacological management of pain in newborns

Objective: to describe the main non-pharmacological interventions for pain relief in newborns available in Neonatal Intensive Care Unit. Method: an exploratory search of the MedLine, Lilacs and Scielo online databases was conducted to retrieve references of studies published from 2004 to 2013. Results: several non-pharmacological interventions were shown to be effective, to represent low risk for neonates and to have a low operational cost. The ones most often discussed in the literature were: oral administration of glucose/sucrose, non-nutritive sucking, breastfeeding, skin-to-skin contact, facilitated tucking and swaddling. Conclusion: healthcare teams should be familiar with these methods and use them more effectively in Neonatal Intensive Care Unit daily routines, so as to ensure that newborns receive qualified and more human care

Melting temperature of screened Wigner crystal on helium films by molecular dynamics

Using molecular dynamics (MD) simulation, we have calculated the melting temperature of two-dimensional electron systems on $240$\AA-$500$\AA helium films supported by substrates of dielectric constants $\epsilon_{s}=2.2-11.9$ at areal densities $n$ varying from $3\times 10^{9}$ cm$^{-2}$ to $1.3\times 10^{10}$ cm$^{-2}$. Our results are in good agreement with the available theoretical and experimental results.Comment: 4 pages and 4 figure