Large atom number Bose-Einstein condensate of sodium

We describe the setup to create a large Bose-Einstein condensate containing more than 120x10^6 atoms. In the experiment a thermal beam is slowed by a Zeeman slower and captured in a dark-spot magneto-optical trap (MOT). A typical dark-spot MOT in our experiments contains 2.0x10^10 atoms with a temperature of 320 microK and a density of about 1.0x10^11 atoms/cm^3. The sample is spin polarized in a high magnetic field, before the atoms are loaded in the magnetic trap. Spin polarizing in a high magnetic field results in an increase in the transfer efficiency by a factor of 2 compared to experiments without spin polarizing. In the magnetic trap the cloud is cooled to degeneracy in 50 s by evaporative cooling. To suppress the 3-body losses at the end of the evaporation the magnetic trap is decompressed in the axial direction.Comment: 11 pages, 12 figures, submitted to Review Of Scientific Instrument

Quantum properties of classical Fisher information

The Fisher information of a quantum observable is shown to be proportional to both (i) the difference of a quantum and a classical variance, thus providing a measure of nonclassicality; and (ii) the rate of entropy increase under Gaussian diffusion, thus providing a measure of robustness. The joint nonclassicality of position and momentum observables is shown to be complementary to their joint robustness in an exact sense.Comment: 16 page

Asymptotic expansions for renewal measures in the plane

Let P be a distribution in the plane and define the renewal measure R=ΣP *n where * denotes convolution. The main results of this paper are three term asymptotic expansions for R far from the origin. As an application, expansions are obtained for distributions in linear boundary crossing problems.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47655/1/440_2004_Article_BF00348749.pd

Growth Diagrams for Individual Finger Strength in Children Measured with the RIHM

Background: Although grip and pinch strength provide a more global measure of a large number of digits and muscles, measuring strength of individual fingers or the thumb can provide additional and more detailed information regarding hand strength. Questions/purposes: We developed growth diagrams for individual finger strength in children. Patients and Methods: We measured thumb palmar abduction, thumb opposition, and thumb flexion in the metacarpophalangeal joint, and abduction of the index and little fingers in 101 children (4-12 years old) using a myometer. We recorded hand dominance, gender, height, and weight. All measurements were performed in a randomized order by the same researcher. We developed statistical models for drawing growth diagrams using estimated percentiles for each strength measurement. Separate models for dominant and nondominant hands of boys and girls were developed, in addition to a combined model. Results: Because there was no difference in strength between boys and girls and between dominant and nondominant hands, both hands and genders were combined in one growth diagram for each measurement. The normative data were presented in a table format and in growth diagrams for each myometer measurement. Conclusions: These diagrams can be used for pediatric patients such as patients with congenital malformations or neuromuscular disorders who receive interventions or therapy aimed at function of the hand, fingers, or thumb. The growth diagrams facilitate distinguishing between the effects of growth and intervention on strength development

Early Active Motion versus Immobilization after Tendon Transfer for Foot Drop Deformity: A Randomized Clinical Trial

Background: Immobilization after tendon transfers has been the conventional postoperative management. Several recent studies suggest early mobilization does not increase tendon pullout. Questions/purposes: To confirm those studies we determined whether when compared with immobilization early active mobilization after a tendon transfer for foot-drop correction would (1) have a similar low rate of tendon insertion pullout, (2) reduce rehabilitation time, and (3) result in similar functional outcomes (active ankle dorsiflexion, plantar flexion, ROM, walking ability, Stanmore score, and resolution of functional problems. Methods: We randomized 24 patients with surgically corrected foot-drop deformities to postoperative treatment with early mobilization with active motion at 5 days (n = 13) or 4 weeks of immobilization with active motion at 29 days (n = 11). In both groups, the tibialis posterior tendon was transferred to the extensor hallucis longus and extensors digitorum communis for foot-drop correction. Rehabilitation time was defined as the time from surgery until discharge from rehabilitation with independent walking. The minimum followup was 16 months (mean, 19 months; range, 16-38 months) in both groups. Results: We observed no case of tendon pullout in either group. Rehabilitation time in the mobilized group was reduced by an average of 15 days. The various functional outcomes were similar in the two groups. Conclusion: In patients with Hansen's disease, an early active mobilization protocol for foot-drop correction has no added risk of tendon pullout and provides similar functional outcomes compared with immobilization. Early mobilization had the advantage of earlier restoration of independent walking. Level of Evidence: Level I, therapeutic study. See Guidelines for Authors for a complete description of levels of evidenc

Test your surrogate data before you test for nonlinearity

The schemes for the generation of surrogate data in order to test the null hypothesis of linear stochastic process undergoing nonlinear static transform are investigated as to their consistency in representing the null hypothesis. In particular, we pinpoint some important caveats of the prominent algorithm of amplitude adjusted Fourier transform surrogates (AAFT) and compare it to the iterated AAFT (IAAFT), which is more consistent in representing the null hypothesis. It turns out that in many applications with real data the inferences of nonlinearity after marginal rejection of the null hypothesis were premature and have to be re-investigated taken into account the inaccuracies in the AAFT algorithm, mainly concerning the mismatching of the linear correlations. In order to deal with such inaccuracies we propose the use of linear together with nonlinear polynomials as discriminating statistics. The application of this setup to some well-known real data sets cautions against the use of the AAFT algorithm.Comment: 14 pages, 15 figures, submitted to Physical Review

Minimal Model for Sand Dunes

We propose a minimal model for aeolian sand dunes. It combines an analytical description of the turbulent wind velocity field above the dune with a continuum saltation model that allows for saturation transients in the sand flux. The model provides a qualitative understanding of important features of real dunes, such as their longitudinal shape and aspect ratio, the formation of a slip face, the breaking of scale invariance, and the existence of a minimum dune size.Comment: 4 pages, 4 figures, replaced with publishd versio

A gauge invariant and string independent fermion correlator in the Schwinger model

We introduce a gauge invariant and string independent two-point fermion correlator which is analyzed in the context of the Schwinger model (QED_2). We also derive an effective infrared worldline action for this correlator, thus enabling the computation of its infrared behavior. Finally, we briefly discuss possible perspectives for the string independent correlator in the QED_3 effective models for the normal state of HTc superconductors.Comment: 14 pages, LaTe