Thermopower induced by a supercurrent in superconductor-normal-metal structures

We examine the thermopower Q of a mesoscopic normal-metal (N) wire in contact to superconducting (S) segments and show that even with electron-hole symmetry, Q may become finite due to the presence of supercurrents. Moreover, we show how the dominant part of Q can be directly related to the equilibrium supercurrents in the structure. In general, a finite thermopower appears both between the N reservoirs and the superconductors, and between the N reservoirs themselves. The latter, however, strongly depends on the geometrical symmetry of the structure.Comment: 4 pages, 4 figures; text compacted and material adde

Long-term adherence to healthy dietary guidelines and chronic inflammation in the prospective Whitehall II study

Background Inflammation plays an important role in the cause of cardiovascular diseases and may contribute to the association linking an unhealthy diet to chronic age-related diseases. However, to date the long-term associations between diet and inflammation have been poorly described. Our aim was to assess the extent to which adherence to a healthy diet and dietary improvements over a 6-year exposure period prevented subsequent chronic inflammation over a 5-year follow-up in a large British population of men and women. Methods Data were drawn from 4600 adults (mean ± standard deviation, age 49.6 ± 6.1 years, 28% were women) from the prospective Whitehall cohort II study. Adherence to a healthy diet was measured using Alternative Healthy Eating Index (AHEI) scores in 1991-1993 (50.7 ± 11.9 points) and 1997-1999 (51.6 ± 12.4 points). Chronic inflammation, defined as average levels of serum interleukin-6 from 2 measures 5 years apart, was assessed in 1997-1999 and 2002-2004. Results After adjustment for sociodemographic factors, health behaviors, and health status, participants who maintained a high AHEI score (ie, a healthy diet, n = 1736, 37.7%) and those who improved this score over time (n = 681, 14.8%) showed significantly lower mean levels of interleukin-6 (1.84 pg/mL, 95% confidence interval [CI], 1.71-1.98 and 1.84 pg/mL, 95% CI, 1.70-1.99, respectively) than those who had a low AHEI score (n = 1594, 34.6%) over the 6-year exposure period (2.01 pg/mL, 95% CI, 1.87-2.17). Conclusions These data suggest that maintaining and improving adherence to healthy dietary recommendations may reduce the risk of long-term inflammation.</p

Nonequilibrium characteristics in all-superconducting tunnel structures

We study the nonequilibrium characteristics of superconducting tunnel structures in the case when one of the superconductors is a small island confined between large superconductors. The state of this island can be probed for example via the supercurrent flowing through it. We study both the far-from-equilibrium limit when the rate of injection for the electrons into the island exceeds the energy relaxation inside it, and the quasiequilibrium limit when the electrons equilibrate between themselves. We also address the crossover between these limits employing the collision integral derived for the superconducting case. The clearest signatures of the nonequilibrium limit are the anomalous heating effects seen as a supercurrent suppression at low voltages, and the hysteresis at voltages close to the gap edge $2\Delta/e$, resulting from the peculiar form of the nonequilibrium distribution function.Comment: 8 pages, 10 figure

Comparison of mean-field theories for vortices in trapped Bose-Einstein condensates

We compute structures of vortex configurations in a harmonically trapped Bose-Einstein condensed atom gas within three different gapless self-consistent mean-field theories. Outside the vortex core region, the density profiles for the condensate and the thermal gas are found to differ only by a few percent between the Hartree-Fock-Bogoliubov-Popov theory and two of its recently proposed gapless extensions. In the core region, however, the differences in the density profiles are substantial. The structural differences are reflected in the energies of the quasiparticle states localized near the vortex core. Especially, the predictions for the energy of the lowest quasiparticle excitation differ considerably between the theoretical models investigated.Comment: 4 pages, 2 figure

Sorption competition and kinetics of trivalent cations (Eu, Y and Cm) on corundum (alpha-Al2O3 ) : A batch sorption and TRLFS study

Abstract In this study we have combined batch sorption and laser spectroscopic investigations to study the sorption of Eu(III) and Cm(III), on the aluminum oxide corundum in single- and multi-metal systems. Experiments were performed using a constant equilibrium time as a function of pH (pH-edges) or at constant pH as a function of equilibrium time (kinetic experiments) in 0.01 M NaClO4 and carbonate free conditions. The objective was to investigate how the sorption behavior of trivalent actinides and lanthanides is affected by the presence of another trivalent metal, Y(III). Our hypothesis was that the addition of higher concentrations of trivalent Y(III) together with a chemically similar trivalent metal, Eu(III) or Cm(III), would affect the sorption behavior of that metal. Batch experiments show that when the concentration of competing Y(III) is high enough (1 × 10−4 M) to occupy most of the surface sites, there is a clear shift in the position of the Eu(III) pH-edge to higher pH. Spectroscopic studies using time-resolved laser fluorescence spectroscopy (TRLFS) clearly confirm sorption competition between the trivalent metals Cm(III) and Y(III), but they also indicate a change in the surface speciation of the trivalent actinide in the presence of the competing metal if the concentration of that competing metal is high enough.Peer reviewe

RydIQule: A Graph-based Paradigm for Modelling Rydberg and Atomic Systems

We describe a numerical technique and accompanying open-source Python software package called RydIQule. RydIQule uses a directional graph, relying on adjacency matrices and path-finding to generate a Hamiltonian for multi-level atomic systems. RydIQule then constructs semi-classical equations of motion (Bloch equations) into a tensor which can store an entire simulation consisting of varied system parameters. Using this framework, RydIQule returns solutions significantly faster than typical for interpreted programming languages. RydIQule extends beyond the capabilities of currently-available tools, facilitating rapid development in atomic and Rydberg spectroscopy. To demonstrate its utility, we use RydIQule to simulate a Doppler-broadened Rydberg atomic sensor that simultaneously demodulates five rf tones spanning from 1.7 to 116 GHz. Using RydIQule, this simulation can be solved in several hours on a commercial off-the-shelf desktop computer.Comment: 5 pages, 3 figure

Palaeoecological evidence of changes in vegetation and climate during the Holocene in the pre-Polar Urals, northeast European Russia

This study investigated Holocene tree-line history and climatic change in the pre-Polar Urals, northeast European Russia. A sediment core from Mezhgornoe Lake situated at the present-day alpine tree-line was studied for pollen, plant macrofossils, Cladocera and diatoms. A peat section from Vangyr Mire in the nearby mixed mountain taiga zone was analysed for pollen. The results suggest that the study area experienced a climatic optimum in the early Holocene and that summer temperatures were at least 2°C warmer than today. Tree birch immigrated to the Mezhgornoe Lake area at the onset of the Holocene. Mixed spruce forests followed at ca. 9500-9000 14C yr BP. Climate was moist and the water level of Mezhgornoe Lake rose rapidly. The hypsithermal phase lasted until ca. 5500-4500 14C yr BP, after which the mixed forest withdrew from the Mezhgornoe catchment as a result of the climate cooling. The gradual altitudinal downward shift of vegetation zones resulted in the present situation, with larch forming the tree-line

Stability of multiquantum vortices in dilute Bose-Einstein condensates

Multiply quantized vortices in trapped Bose-Einstein condensates are studied using the Bogoliubov theory. Suitable combinations of a localized pinning potential and external rotation of the system are found to energetically stabilize, both locally and globally, vortices with multiple circulation quanta. We present a phase diagram for stable multiply quantized vortices in terms of the angular rotation frequency and the width of the pinning potential. We argue that multiquantum vortices could be experimentally created using these two expedients.Comment: 5 pages, 4 figure

Primary Sequences of Protein-Like Copolymers: Levy Flight Type Long Range Correlations

We consider the statistical properties of primary sequences of two-letter HP copolymers (H for hydrophobic and P for polar) designed to have water soluble globular conformations with H monomers shielded from water inside the shell of P monomers. We show, both by computer simulations and by exact analytical calculation, that for large globules and flexible polymers such sequences exhibit long-range correlations which can be described by Levy-flight statistics.Comment: 4 pages, including 2 figures; several references added, some formulations improve