1,462 research outputs found
Structural phase transitions of vortex matter in an optical lattice
We consider the vortex structure of a rapidly rotating trapped atomic
Bose-Einstein condensate in the presence of a co-rotating periodic optical
lattice potential. We observe a rich variety of structural phases which reflect
the interplay of the vortex-vortex and vortex-lattice interactions. The lattice
structure is very sensitive to the ratio of vortices to pinning sites and we
observe structural phase transitions and domain formation as this ratio is
varied.Comment: 4 pages, 3 figure
High rate production of polarized 3He with meta-stability exchange method
Keywords: polarized 3He, meta-stability exchange, infrared laserComment: 4 figures, submitted to J. Phys. Soc. Jpn
Atmospheric frontal zone studies
The research supported by this contract and directed Activities in the inversion and interpretation of data produced by the Nimbus-7 scanning multichannel microwave radiometer (SMMR) are reported. There were five principal subjects: (1) modeling of the emissivity of foam patches on the ocean surface; (2) inversion of radiometric data by a multidimensional algorithm; (3) an operational water vapor retrieval algorithm; (4) inference of Antarctic firm accumulation rates; and (5) inference of water vapor over the Arctic sea ice
Controlling quasiparticle excitations in a trapped Bose-Einstein condensate
We describe an approach to quantum control of the quasiparticle excitations
in a trapped Bose-Einstein condensate based on adiabatic and diabatic changes
in the trap anisotropy. We describe our approach in the context of Landau-Zener
transition at the avoided crossings in the quasiparticle excitation spectrum.
We show that there can be population oscillation between different modes at the
specific aspect ratios of the trapping potential at which the mode energies are
almost degenerate. These effects may have implications in the expansion of an
excited condensate as well as the dynamics of a moving condensate in an atomic
wave guide with a varying width
Is arrhythmogenicity related to the speed of reperfusion during thrombolysis for myocardial infarction?
The objective of this study was to relate the number of ventricular arrhythmias (VA) to the normalization time of the ST segment during thrombolysis for acute myocardial infarction. The 24 h Holter recordings, begun on start of intravenous thrombolytic therapy, and the 12-lead electrocardiograms of 41 patients with a patent infarct-related artery according to coronary angiography were analysed. The mean time from onset of chest pain to angiography was 30.5Ā±3.1 h, ā„24 h in 59%. The normalization time of the ST segment, assessed by the time of decrease of ST segment elevation from start of Holter recording to normal or steady state was ā„60 min in 13 patients (group 1), 60 to 180 min in 15 patients (group 2) and > 180 min in 13 patients (group 3). The incidence of VA was similar in all groups, except for ventricular tachycardias (VT) >15 beats (group 1:69%, group 2:13%, group 3:15%, P=0.002) The frequency of accelerated idioventricular rhythms (AIVR), early AIVR (ā¤6 h) and of VT was significantly higher in group 1 than in group 3 with a 8-, 30- and 6- fold increase, respectively (back transformed mean). We conclude that the number of V As is related to the normalization time of the ST segment during reperfusion. This may suggest that faster reflow is more arrhythmogeni
Watching a superfluid untwist itself: Recurrence of Rabi oscillations in a Bose-Einstein condensate
The order parameter of a condensate with two internal states can continuously
distort in such a way as to remove twists that have been imposed along its
length. We observe this effect experimentally in the collapse and recurrence of
Rabi oscillations in a magnetically trapped, two-component Bose-Einstein
condensate of ^87Rb
A Comprehensive GCāMS Sub-Microscale Assay for Fatty Acids and its Applications
Fatty acid analysis is essential to a broad range of applications including those associated with the nascent algal biofuel and algal bioproduct industries. Current fatty acid profiling methods require lengthy, sequential extraction and transesterification steps necessitating significant quantities of analyte. We report the development of a rapid, microscale, single-step, in situ protocol for GCāMS lipid analysis that requires only 250Ā Ī¼g dry mass per sample. We furthermore demonstrate the broad applications of this technique by profiling the fatty acids of several algal species, small aquatic organisms, insects and terrestrial plant material. When combined with fluorescent techniques utilizing the BODIPY dye family and flow cytometry, this micro-assay serves as a powerful tool for analyzing fatty acids in laboratory and field collected samples, for high-throughput screening, and for crop assessment. Additionally, the high sensitivity of the technique allows for population analyses across a wide variety of taxa
Observation of anomalous spin-state segregation in a trapped ultra-cold vapor
We observe counter-intuitive spin segregation in an inhomogeneous sample of
ultra-cold, non-condensed Rubidium atoms in a magnetic trap. We use spatially
selective microwave spectroscopy to verify a model that accounts for the
differential forces on two internal spin states. In any simple understanding of
the cloud dynamics, the forces are far too small to account for the dramatic
transient spin polarizations observed. The underlying mechanism remains to be
elucidated.Comment: 5 pages, 3 figure
- ā¦