Yang-Yang thermodynamics on an atom chip

We investigate the behavior of a weakly interacting nearly one-dimensional (1D) trapped Bose gas at finite temperature. We perform in situ measurements of spatial density profiles and show that they are very well described by a model based on exact solutions obtained using the Yang-Yang thermodynamic formalism, in a regime where other, approximate theoretical approaches fail. We use Bose-gas focusing [Shvarchuck etal., Phys. Rev. Lett. 89, 270404 (2002)] to probe the axial momentum distribution of the gas, and find good agreement with the in situ results.Comment: extended introduction and conclusions, and minor changes throughout; accepted for publication in Phys. Rev. Let

A Comparison of Self-Administered Proprioceptive Neuromuscular Facilitation To Static Stretching On Range of Motion and Flexibility

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'Appreciating' Drainage Assets in New Zealand Cities: Rain Garden Treatment and Hydraulic Performance

Despite recognising rain gardens as a best management practice (BMP) to mitigate urban stormwater runoff, there is a dearth of knowledge about their treatment and infiltration performance. It is believed that organic substrates may enhance some contaminant removal but hinder hydraulic throughput although data showing this is sparse. In order to evaluate the influence of substrate composition on bioinfiltrative system effectiveness, mesocosm-scale (180 L, 0.17 m2) laboratory rain gardens were established. Saturated (constant head) hydraulic conductivity was determined before and after the experimental treatment tests that employed stormwater collected from a neighbouring catchment to investigate contaminant removal efficiencies. The principal contaminant (Zn, Cu, Pb and nutrients) removal efficiencies were investigated for three substrates comprising various proportions of organic topsoil. All total metal concentrations in the effluent were <50% of influent concentrations, with the exception of copper in the topsoil-only system that had negligible reduction due to a high dissolved fraction. The system comprising topsoil only had the lowest saturated hydraulic conductivity of 162 mm/hr and demonstrated the poorest metal (Cu, Zn) removal efficiencies. Interestingly, the system with a combination of sand and topsoil demonstrated most promising metal removal of Cu (53%), Zn (81.2%) and Pb (89.1%) with adequate hydraulic performance (296 mm/hr) required for a stormwater infiltrative system. Overall, metal removal was greater at an effluent pH of 7.38 compared to the 6.24 pH provided in the raw stormwater. Some pH buffering was provided by the calcareous sand in two of the systems, whereas the topsoil-only system lacked such buffering potential to facilitate adequate metal removal. These data highlight the influence of organic topsoil on pH that clearly governs metal speciation and hence removal efficacy in bioinfiltrative systems. Nitrate was net exported from all the systems, especially topsoil contrary to what is believed to be easily removed

Sprinting Velocity Increases Through Postactivation Potentiation with a Hex-Bar Farmers Walk

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Yang-Yang thermodynamics on an atom chip

We investigate the behavior of a weakly interacting nearly one-dimensional (1D) trapped Bose gas at finite temperature. We perform in situ measurements of spatial density profiles and show that they are very well described by a model based on exact solutions obtained using the Yang-Yang thermodynamic formalism, in a regime where other, approximate theoretical approaches fail. We use Bose-gas focusing [Shvarchuck etal., Phys. Rev. Lett. 89, 270404 (2002)] to probe the axial momentum distribution of the gas, and find good agreement with the in situ results.Comment: extended introduction and conclusions, and minor changes throughout; accepted for publication in Phys. Rev. Let

Stability and electronic structure of the complex K2_2PtCl6_6 structure-type hydrides

The stability and bonding of the ternary complex K$_2$PtCl$_6$ structure hydrides is discussed using first principles density functional calculations. The cohesion is dominated by ionic contributions, but ligand field effects are important, and are responsible for the 18-electron rule. Similarities to oxides are discussed in terms of the electronic structure. However, phonon calculations for Sr$_2$RuH$_6$ also show differences, particularly in the polarizability of the RuH$_6$ octahedra. Nevertheless, the yet to be made compounds Pb$_2$RuH$_6$ and Be$_2$FeH$_6$ are possible ferroelectrics. The electronic structure and magnetic properties of the decomposition product, FeBe$_2$ are reported. Implications of the results for H storage are discussed

Box traps on an atom chip for one-dimensional quantum gases

We present the implementation of tailored trapping potentials for ultracold gases on an atom chip. We realize highly elongated traps with box-like confinement along the long, axial direction combined with conventional harmonic confinement along the two radial directions. The design, fabrication and characterization of the atom chip and the box traps is described. We load ultracold ($\lesssim1 \mu$K) clouds of $^{87}$Rb in a box trap, and demonstrate Bose-gas focusing as a means to characterize these atomic clouds in arbitrarily shaped potentials. Our results show that box-like axial potentials on atom chips are very promising for studies of one-dimensional quantum gases.Comment: 9 pages 4 figure